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  • Targeting nuclear proteins for control of viral replication
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2019-01-21
    Wen Meng; Xiao-Jia Wang; Hwa-Chain Robert Wang

    Viruses are obligate intracellular parasites that exploit host cell machineries for replication. In this review, we focus on the current understanding of host cell nuclear proteins whose translocation from the nucleus to cytoplasm is induced and utilized by viruses to support viral replication and infection. Utilization of nuclear proteins for viral replication and infection involves disruption of nuclear import, enhancement of nuclear export, removal of nuclear localization signal (NLS) from nuclear proteins and alteration of nuclear pore complexes (NPCs) to cooperatively support viral replication. Understanding of nucleo-cytoplasmic transport system, and associated mechanisms, utilized by viruses will advance therapeutic development of strategies to produce optimal antiviral agents effective in control of viral diseases.

    更新日期:2020-01-04
  • An update on possible pathogenic mechanisms of periodontal pathogens on renal dysfunction
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2019-02-07
    Aditi Chopra; Karthik Sivaraman

    Periodontitis is a potential source of permanent systemic inflammation that initiates renal dysfunction and contributes to the development of chronic kidney diseases (CKDs). Although numerous studies have confirmed the bidirectional role of periodontal infection and renal inflammation, no literature has yet highlighted the sophisticated pathogenic mechanisms by which periodontal pathogens, particularly Porphynomonas Gingivalis, induce renal dysfunction and contributed in the development of CKDs. The present review aims to critically analyze and highlight the novel pathogenesis of periodontitis induced CKDs.

    更新日期:2020-01-04
  • Bacterial translocation in acute pancreatitis
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2019-12-18
    Jinbo Liu; Lin Huang; Ming Luo; Xianming Xia

    Bacterial translocation is a phenomenon in which live bacteria or their products cross the intestinal barrier to other organs or the circulatory system. Gut translocation of bacteria has been reported in both animal models, and clinical trials often accompany acute pancreatitis and are believed to be linked to patient outcome, especially in severe acute pancreatitis. Therefore, the mechanisms of intestinal bacterial translocation in acute pancreatitis have become a topic of interest in recent years. This review discusses Bacterial translocation in acute pancreatitis, identifies possible mechanisms of action, and provides an overview of the methods used to detect Bacterial translocation in acute pancreatitis. This review also highlights areas that require further research.

    更新日期:2020-01-04
  • Rewiring of transcriptional networks as a major event leading to the diversity of asexual multicellularity in fungi
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2019-07-03
    Oier Etxebeste; Ainara Otamendi; Aitor Garzia; Eduardo A. Espeso; Marc S. Cortese

    Complex multicellularity (CM) is characterized by the generation of three-dimensional structures that follow a genetically controlled program. CM emerged at least five times in evolution, one of them in fungi. There are two types of CM programs in fungi, leading, respectively, to the formation of sexual or asexual spores. Asexual spores foment the spread of mycoses, as they are the main vehicle for dispersion. In spite of this key dependence, there is great morphological diversity of asexual multicellular structures in fungi. To advance the understanding of the mechanisms that control initiation and progression of asexual CM and how they can lead to such a remarkable morphological diversification, we studied 503 fungal proteomes, representing all phyla and subphyla, and most known classes. Conservation analyses of 33 regulators of asexual development suggest stepwise emergence of transcription factors. While velvet proteins constitute one of the most ancient systems, the central regulator BrlA emerged late in evolution (with the class Eurotiomycetes). Some factors, such as MoConX4, seem to be species-specific. These observations suggest that the emergence and evolution of transcriptional regulators rewire transcriptional networks. This process could reach the species level, resulting in a vast diversity of morphologies.

    更新日期:2020-01-04
  • Non-antibiotic microbial solutions for bovine mastitis – live biotherapeutics, bacteriophage, and phage lysins
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2019-08-12
    Angeliki Angelopoulou; Alicja K. Warda; Colin Hill; R. Paul Ross

    Bovine mastitis is a disease with a multi-etiological nature, defined as an inflammation of the udder. The main treatment for mastitis is the administration of antibiotics – usually directly to the udder. There is an urgent need for novel therapies to treat and prevent the disease, given the widespread emergence of antibiotic resistance and concomitant problems in the treatment of human and animal infections. We provide an overview of treatments for bovine mastitis, with emphasis on probiotics, bacteriocins, bacteriophages (phages), and phage endolysins. Probiotics have in recent years proved to be particularly efficacious in bovine mastitis treatment and prevention. In this case, the mode of action is most likely to be due to stimulation of the host immune response which clears the mastitis pathogen. Bacteriocins have the potential to be incorporated into teat washes and wipes, thus preventing pathogen spread on the farm. Phage therapy is limited by the inability of some phages to replicate in raw milk, as reported for some staphylococcal phages, and by their narrow host specificity. The use of phage endolysins is more promising, by enabling the development of broad host range potent antimicrobials, but additional research is required in terms of efficacy, safety and production.

    更新日期:2020-01-04
  • Roles of HSV-1 infection-induced microglial immune responses in CNS diseases: friends or foes?
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2019-09-12
    Yiliang Wang; Jiaoyan Jia; Yun Wang; Feng Li; Xiaowei Song; Shurong Qin; Zhaoyang Wang; Kaio Kitazato; Yifei Wang

    Microglia, as brain-resident macrophages, are the first line of defense against brain invading pathogens. Further, their dysfunction has been recognized to be closely associated with mounting CNS diseases. Of note, chronic HSV-1 infection leads to the persistent activation of microglia, which elicit a comprehensive response by generating certain factors with neurotoxic and neuroprotective effects. CNS infection with HSV-1 results in herpes simplex encephalitis and herpes simplex keratitis. Microglial immune response plays a crucial role in the development of these diseases. Moreover, HSV-1 infection is strongly associated with several CNS diseases, especially Alzheimer’s disease and schizophrenia. These CNS diseases can be effectively ameliorated by eliciting an appropriate immune response, such as inhibition of microglial proliferation and activation. Therefore, it is crucial to reassess the positive and negative roles of microglia in HSV-1 CNS infection for a more comprehensive and detailed understanding of the relationship between microglia and CNS diseases. Hence, the present review focuses on the dual roles of microglia in mediating HSV-1 CNS infection, as well as on the strategy of targeting microglia to ameliorate CNS diseases. Further research in this field can help comprehensively elucidate the dual role of the microglial immune response in HSV-1 CNS infection, providing a theoretical basis for identifying therapeutic targets against overactive microglia in CNS diseases and HSV-1 infection.

    更新日期:2020-01-04
  • Otitis media pathogens – A life entrapped in biofilm communities
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2019-09-10
    Maria Daniela Silva; Sanna Sillankorva

    Otitis media is a group of inflammatory diseases of the middle ear with great impact on children worldwide. The most common reported bacterial pathogens are Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis. Over the last years, the role of biofilms formed by otopathogens that contribute to otitis media recurrence and chronicity has been established. An improved understanding of the properties of biofilms formed by these bacteria, which factors influence them, and how these affect the host inflammatory response is important for the development of novel strategies for the treatment of otitis media. This review focuses on the biofilm nature that the most prevalent otopathogens adopt in otitis media infections. In addition, new treatment approaches targeting biofilms are highlighted.

    更新日期:2020-01-04
  • Microbial transmission from mother to child: improving infant intestinal microbiota development by identifying the obstacles
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2019-12-20
    Emmy Van Daele; Jan Knol; Clara Belzer

    (2019). Microbial transmission from mother to child: improving infant intestinal microbiota development by identifying the obstacles. Critical Reviews in Microbiology: Vol. 45, No. 5-6, pp. 613-648.

    更新日期:2020-01-04
  • Betaproteobacteria are predominant in drinking water: are there reasons for concern?
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2019-11-05
    Pompeyo Ferro; Ivone Vaz-Moreira; Célia M. Manaia

    Betaproteobacteria include some of the most abundant and ubiquitous bacterial genera that can be found in drinking water, including mineral water. The combination of physiology and ecology traits place some Betaproteobacteria in the list of potential, yet sometimes neglected, opportunistic pathogens that can be transmitted by water or aqueous solutions. Indeed, some drinking water Betaproteobacteria with intrinsic and sometimes acquired antibiotic resistance, harbouring virulence factors and often found in biofilm structures, can persist after water disinfection and reach the consumer. This literature review summarises and discusses the current knowledge about the occurrence and implications of Betaproteobacteria in drinking water. Although the sparse knowledge on the ecology and physiology of Betaproteobacteria thriving in tap or bottled natural mineral/spring drinking water (DW) is an evidence of this review, it is demonstrated that DW holds a high diversity of Betaproteobacteria, whose presence may not be innocuous. Frequently belonging to genera also found in humans, DW Betaproteobacteria are ubiquitous in different habitats, have the potential to resist antibiotics either due to intrinsic or acquired mechanisms, and hold different virulence factors. The combination of these factors places DW Betaproteobacteria in the list of candidates of emerging opportunistic pathogens. Improved bacterial identification of clinical isolates associated with opportunistic infections and additional genomic and physiological studies may contribute to elucidate the potential impact of these bacteria.

    更新日期:2020-01-04
  • mNGS in clinical microbiology laboratories: on the road to maturity
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2019-11-06
    Dongsheng Han; Ziyang Li; Rui Li; Ping Tan; Rui Zhang; Jinming Li

    Metagenomic next-generation sequencing (mNGS) is increasingly being applied in clinical laboratories for unbiased culture-independent diagnosis. Whether it can be a next routine pathogen identification tool has become a topic of concern. We review the current implementation of this new technology for infectious disease diagnostics and discuss the feasibility of transforming mNGS into a routine diagnostic test. Since 2008, numerous studies from over 20 countries have revealed the practicality of mNGS in the work-up of undiagnosed infectious diseases. mNGS performs well in identifying rare, novel, difficult-to-detect and coinfected pathogens directly from clinical samples and presents great potential in resistance prediction by sequencing the antibiotic resistance genes, providing new diagnostic evidence that can be used to guide treatment options and improve antibiotic stewardship. Many physicians recognized mNGS as a last resort method to address clinical infection problems. Although several hurdles, such as workflow validation, quality control, method standardisation, and data interpretation, remain before mNGS can be implemented routinely in clinical laboratories, they are temporary and can be overcome by rapidly evolving technologies. With more validated workflows, lower cost and turnaround time, and simplified interpretation criteria, mNGS will be widely accepted in clinical practice. Overall, mNGS is transforming the landscape of clinical microbiology laboratories, and to ensure that it is properly utilised in clinical diagnosis, both physicians and microbiologists should have a thorough understanding of the power and limitations of this method.

    更新日期:2020-01-04
  • Fungi in archives, libraries, and museums: a review on paper conservation and human health
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2019-12-09
    Ana Catarina Pinheiro; Sílvia Oliveira Sequeira; Maria Filomena Macedo

    The action of fungi on books, documents, maps, and works of art on paper can result in inestimable cultural losses. Plus, some of the fungi present in paper documents, surfaces and air from archives, libraries and museums are also a threat to human health. This work aims to review the literature on the most important and frequent microfungal populations found in paper-based collections all over the world, and correlate these data with human health risks. A total of 71 studies, dating between 1997 and 2018 were reviewed and organized. From 27 different countries, 207 fungal genera and 580 species were reported. Chaetomium sp. and Fusarium sp. were found to be special contaminants in the air of archives and have been associated with paper biodeterioration. The most common fungi reported (e.g. Penicillium, Aspergillus, and Alternaria species) have an impact on paper conservation but can also cause adverse human health effects. The most frequent fungal species retrieved from discoloured paper materials are discussed in greater detail. Considerations on methods of identification and quantification of fungal contamination are also presented. Finally, the authors acknowledge an urgent need for standardizing research in this area and further studies are proposed.

    更新日期:2020-01-04
  • Phages amid antimicrobial resistance
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2019-11-27
    Juliet Roshini Mohan Raj; Indrani Karunasagar

    Increasing levels of resistance to antimicrobial agents have created chaos in the health sector, with several infections not responding to antibiotic treatments. Search for alternative strategies has looked at bacteriophages as potential therapeutics and in the last couple of years. There are reports of phages being successfully used to treat life-threatening infections. Phages are also mobile elements that exchange genes between and within different bacterial species and account significantly for strain differences across and within a species. A gap in metagenomics analysis and conservative methods of detection have failed to give an accurate account of the role of bacteriophages in antimicrobial resistance. Recent studies have focussed on the role of bacteriophages in the adaptation of pathogens to new hosts and the emergence of multidrug-resistance, which are a significant concern against phage therapy. This article presents a comprehensive account of weighing the odds of phage therapy verses phage-mediated antimicrobial resistance.

    更新日期:2020-01-04
  • Pseudomonas aeruginosa and Staphylococcus aureus communication in biofilm infections: insights through network and database construction
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2019-12-13
    Andreia Patrícia Magalhães; Paula Jorge; Maria Olívia Pereira

    The polymicrobial nature of most infections is often characterized by complex biofilm communities, where pathogen interactions promote infection progression and severity. Quorum-sensing, the major regulator of virulence and inter-species communication, is a promising target for new anti-infective strategies. This study aimed at collecting and analysing experimental information on the molecular basis of Pseudomonas aeruginosa and Staphylococcus aureus interactions in biofilms. Data were systematically annotated from relevant full-text papers optimally retrieved from PubMed, reconstructed as networks and integrated with specialized databases to identify promising antimicrobial targets. Network analysis revealed key entities regulating P. aeruginosa/S. aureus interactions, for instance the PqsABCDE/PqsR quorum-sensing system, which affects S. aureus growth and biofilm formation. By identifying the most reported P. aeruginosa virulence factors affecting S. aureus, for example, HQNO and siderophores, a list of experimentally validated agents affecting those factors, ranging from synthetic drugs to natural plant extracts, was constructed. The complex experimental data on P. aeruginosa/S. aureus interactions were for the first time systematically organized and made publically available in the new Inter-Species CrossTalk Database (www.ceb.uminho.pt/ISCTD).

    更新日期:2020-01-04
  • The current novel therapeutic regimens for Clostridium difficile infection (CDI) and the potentials of Traditional Chinese Medicine in treatment of CDI
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2019-12-14
    Yan Gao; Hui Li; Hongjun Yang; Jianrong Su; Luqi Huang

    Clostridium difficile infection (CDI) is featured as the dysbiosis of gut microbiota and consequent mild diarrhoea or severe pseudomembranous colitis. However, the frequent recurrence of CDI following treatment course challenged the antibiotic therapy. Currently, to address the relapse of CDI, several novel therapeutic approaches have emerged, including Bezlotoxumab, SYN-004 (Ribaxamase), RBX2660, and faecal microbial transplant. Traditional Chinese Medicine (TCM) is an old medical system accumulated for thousands of years. Orientated by syndrome-based treatment, TCM functions in a multicomponent and multitarget mode. This old medical system showed superiority over conventional medical treatment, particularly in the treatment of complex disorders, including CDI. In the present review, we will elaborate the TCM intervention in the management of CDI and others disorders via restoring the gut microbiota dysbiosis. We hope that this review will deepen our understanding of TCM as an alternative to CDI treatment. However, more rigorously designed basic researches and randomised controlled trials need to conduct to appraise the function mechanisms and effects of TCM. Finally, it is concluded that the combined therapeutic potentials of TCM and western medicine could be harness to resolve the recurrence and improve the outcome of CDI.

    更新日期:2020-01-04
  • Steering soil microbiome to enhance soil system resilience
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2019-12-13
    Likun Wang; Xiaofang Li

    Pathogens in soil play a tremendous role in soil health and subsequent food production. Soil-borne pathogens can cause serious losses to global harvest and are considered as a difficult problem to manage worldwide. The emergence of soil disease is largely dependent on the pathogen-host-environment complex, which can be employed to generate pathogen control strategies. Usually, the resources of resistant plant varieties are limited, and chemical control is insufficiently effective with possible secondary soil pollution. Therefore, there is now a compulsory need to enhance the ability of soil per se to defend against invading pathogens (i.e. soil immunity). Soil immunity is normally attributed to the activities of the functional microbiome. In the meanwhile, pathogen-microbiome interactions in soil are sensitive to soil contaminants which would filter out unique groups of microbial communities. Steering functional soil microbiome will not only limit disease development, but also reduce the level of soil pollution. It is thus of great importance to develop microbiome-based techniques to improve soil immunity and resilience. This review provided an up-to-date understanding of the mechanisms for microbiome-based disease suppression and potential management strategies for better sustainable agricultural system.

    更新日期:2020-01-04
  • Phages amid antimicrobial resistance.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : null
    Juliet Roshini Mohan Raj,Indrani Karunasagar

    Increasing levels of resistance to antimicrobial agents have created chaos in the health sector, with several infections not responding to antibiotic treatments. Search for alternative strategies has looked at bacteriophages as potential therapeutics and in the last couple of years. There are reports of phages being successfully used to treat life-threatening infections. Phages are also mobile elements that exchange genes between and within different bacterial species and account significantly for strain differences across and within a species. A gap in metagenomics analysis and conservative methods of detection have failed to give an accurate account of the role of bacteriophages in antimicrobial resistance. Recent studies have focussed on the role of bacteriophages in the adaptation of pathogens to new hosts and the emergence of multidrug-resistance, which are a significant concern against phage therapy. This article presents a comprehensive account of weighing the odds of phage therapy verses phage-mediated antimicrobial resistance.

    更新日期:2019-11-01
  • Treatment of colored effluents with lignin-degrading enzymes: an emerging role of marine-derived fungi.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2008-11-13
    Chandralata Raghukumar,Donna D'Souza-Ticlo,Ashutosh Kumar Verma

    Some of the industries that discharge highly colored effluents are paper and pulp mills, textiles and dye-making industries, alcohol distilleries, and leather industries. Terrestrial white-rot basidiomycetous fungi and their lignin-degrading enzymes laccase, manganese-peroxidase and lignin peroxidases are useful in the treatment of colored industrial effluents and other xenobiotics. Free mycelia, mycelial pellets, immobilized fungi or their lignin-degrading enzymes from terrestrial fungi have been reported in treatment of several effluents. Marine obligate or facultative (marine-derived) fungi may have unique properties but have not been explored sufficiently for this purpose. This article presents a critical review of bioremediation potential of such fungi and their lignin-degrading enzymes in comparison with the state-of-the-art in terrestrial white-rot fungi.

    更新日期:2019-11-01
  • The properties and functions of virus encoded microRNA, siRNA, and other small noncoding RNAs.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2008-10-31
    Shunmin He,Zhen Yang,Geir Skogerbo,Fei Ren,Hongliang Cui,Haitao Zhao,Runsheng Chen,Yi Zhao

    microRNAs (miRNAs) represent a class of noncoding RNA species, believed to be regulating gene expression by binding to complementary sites in the 3'UTRs of target mRNAs. They play important regulatory roles in various metabolic pathways in most eukaryotes. The recent discovery of virus encoded miRNAs suggests that viruses may be using them to regulate host and viral gene expression. Another class of closely related small interfering RNAs (siRNAs) also has been found within the HIV-1 genome and shown to be exerting a limited impact on virus reproduction. Additionally, an additional type of viral noncoding RNAs named small noncoding RNAs (sncRNAs) ranging from a few tens to a few hundred nucleotides in length, has also been identified. sncRNAs have a wide phylogenesis and high levels of expression, suggesting they may play an important roles in different species. Here we discuss the genomic organization, expression, conservation as well as potential function of virally encoded miRNA, siRNA, and sncRNAs.

    更新日期:2019-11-01
  • Ecology of E. coli O157:H7 and Salmonella enterica in the primary vegetable production chain.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2008-08-30
    Eelco Franz,Ariena H C van Bruggen

    There is an increased concern that plants might be more important as a carrier for human enteric pathogens like E. coli O157:H7 and Salmonella enterica serovars than previously thought. This review summarizes the knowledge available on the ecology of E. coli O157:H7 and Salmonella enterica in the primary production chain of leafy green vegetables (in particular lettuce), including manure, manure-amended soil, and crop. Based on the available literature, suggestions are made for the control of these pathogens. The suggested approach of oligotrophication of agro-ecosystems fits in the wider approach to lower environmental emissions of nutrients from manure application and to enhance the suppression against plant pathogens.

    更新日期:2019-11-01
  • Pneumococcal surface adhesin A (PsaA): a review.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2008-08-30
    Gowrisankar Rajam,Julie M Anderton,George M Carlone,Jacquelyn S Sampson,Edwin W Ades

    Pneumococcal surface adhesin A (PsaA) is a surface-exposed common 37-kilodalton multi-functional lipoprotein detected on all known serotypes of Streptococcus pneumoniae. This lipoprotein belongs to the ABC-type transport protein complex that transports Mn2+; it is also an adhesin that plays a major role in pneumococcal attachment to the host cell and virulence. PsaA is immunogenic and natural nasopharyngeal colonization of pneumococci elicits an increase in antibody towards PsaA. Hence, PsaA is being actively evaluated as a component of a vaccine in formulations composed of pneumococcal common proteins. PsaA has been expressed as an E. coli recombinant protein, purified, and evaluated in a phase one clinical trial. This article reviews PsaA, its structure and role in pneumococcal virulence, immunogenicity, and potential to reduce nasopharyngeal colonization (a major prerequisite for pneumococcal pathogenesis) as a component of a common pneumococcal protein vaccine.

    更新日期:2019-11-01
  • Thermotolerant hydrogenases: biological diversity, properties, and biotechnological applications.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2008-08-30
    Jed O Eberly,Roger L Ely

    Hydrogenases are metalloproteins that catalyze the oxidation and reduction of molecular hydrogen and play a crucial role in many microbial metabolic processes. A subset of hydrogenases capable of functioning at temperatures from 50 to 125 degrees C is found in thermophilic microorganisms. Most known thermotolerant hydrogenases contain a [NiFe] active site and are either bidirectional or uptake type. Although no exhaustive survey has been done of the ecological diversity of thermophilic hydrogen-reducing or oxidizing bacteria, they appear to exist in virtually every thermophilic environment examined to date. Thermotolerant hydrogenases share many similarities with their mesophilic counterparts, but they have several features in addition to thermotolerance that make them especially well suited for biotechnological applications. Ongoing research is focused on potential applications of thermotolerant H2 ases in biosynthesis, H2 production, bioremediation, and biosensors.

    更新日期:2019-11-01
  • Properties and applications of antimicrobial peptides in biodefense against biological warfare threat agents.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2008-06-24
    Raymond Murray Dawson,Chun-Qiang Liu

    Recent advances in knowledge of the properties of antimicrobial peptides (AMPs) are reviewed. AMPs are typically small, positively charged, amphipathic peptides that interact electrostatically and non-stereospecifically with the bacterial cell membrane, resulting in its permeabilization and cell death. Classes of AMPs, their mechanisms of action, hemolytic activity, and cytotoxicity towards host cells are discussed. A particular focus is AMPs with potential for use in defense against biological warfare agents. Some AMPs cytotoxic to Bacillus anthracis have been described. Synthesis of these peptides in multivalent form leads to a synergistic increase in antibacterial activity. Strategies to enhance the potency, stability, and selectivity of AMPs are discussed.

    更新日期:2019-11-01
  • A perspective on the biotechnological potential of microalgae.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2008-06-24
    R Raja,S Hemaiswarya,N Ashok Kumar,S Sridhar,R Rengasamy

    Microalgae are the untapped resource with more than 25,000 species of which only 15 are in use. In recent years, microalgal culture technology is a business oriented line owing to their different practical applications. Innovative processes and products have been introduced in microalgal biotechnology to produce vitamins, proteins, cosmetics, and health foods. For most of these applications, the market is still developing and the biotechnological use of microalgae will extend into new areas. With the development of sophisticated culture and screening techniques, microalgal biotechnology can meet the challenging demands of both the food and pharmaceutical industries. Genetic improvement should also play an important role in the future development of algal industries. Based on the preliminary research, several therapeutic benefits have been claimed for commercially produced microalgae including AIDS, cancer, and Cerebro vascular diseases. In near future, algal biomass will serve as a renewable energy source through commercial production of hydrocarbon by Botryococcus throughout the world.

    更新日期:2019-11-01
  • False-negative results in nucleic acid amplification tests-do we need to routinely use two genetic targets in all assays to overcome problems caused by sequence variation?
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2008-06-24
    D M Whiley,S B Lambert,S Bialasiewicz,N Goire,M D Nissen,T P Sloots

    Nucleic acid amplification tests (NAATs) have numerous advantages over traditional diagnostic techniques and so are now widely used by diagnostic laboratories for routine detection of infectious agents. However, there is some concern over the increasing numbers of reports of NAAT false-negative results caused by sequence variation. Highly conserved NAAT target sequences have been reported for many organisms, yet sequence-related problems continue to be observed in commercial and in-house assays targeting a broad range of microbial pathogens. In light of these ongoing problems, it may be time to consider the use of two genetic targets in NAAT methods to reduce the potential for sequence-related false-negative results.

    更新日期:2019-11-01
  • Nanotechnology and water treatment: applications and emerging opportunities.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2008-02-09
    J Theron,J A Walker,T E Cloete

    Nanotechnology, the engineering and art of manipulating matter at the nanoscale (1-100 nm), offers the potential of novel nanomaterials for treatment of surface water, groundwater, and wastewater contaminated by toxic metal ions, organic and inorganic solutes, and microorganisms. Due to their unique activity toward recalcitrant contaminants and application flexibility, many nanomaterials are under active research and development. Accordingly, literature about current research on different nanomaterials (nanostructured catalytic membranes, nanosorbents, nanocatalysts, and bioactive nanoparticles) and their application in water treatment, purification and disinfection is reviewed in this article. Moreover, knowledge regarding toxicological effects of engineered nanomaterials on humans and the environment is presented.

    更新日期:2019-11-01
  • Diagnosis in periodontology: a further aid through microbiological tests.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2008-02-09
    Simonetta D'Ercole,Giovanni Catamo,Raffaele Piccolomini

    Most of the current knowledge of the complex microbiology of oral biofilms, which initiates and maintains periodontal lesions, has been facilitated by the introduction of molecular techniques. Several studies exalt the high sensitivity and specificity of molecular tests in the detection and quantification of periodontal pathogens. Although they have large a diffusion, the old method of bacterial culture remains nowadays the gold standard when determining the utility of a new microbial test. Moreover, cultures have the important advantage of allowing an antibiotic sensitivity test and this is much more important during the treatment of patients with aggressive periodontitis.

    更新日期:2019-11-01
  • Biodegradation of aromatic compounds: an overview of meta-fission product hydrolases.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2008-02-09
    Syed Khajamohiddin,Elisha Raju Repalle,Aleem Basha Pinjari,Mike Merrick,Dayananda Siddavattam

    Meta fission product (MFP) hydrolases catalyze hydrolysis of a low reactive carbon-carbon bond found in meta-fission products, generated during biodegradation of various aromatic compounds. These enzymes belong to the alpha/beta hydrolase super family and show structural conservation despite having poor sequence similarity. MFP-hydrolases are substrate specific and studies have indicated that this substrate specificity plays a key role in the determination of the organism's ability to degrade a particular substrate. In this concise review of MFP-hydrolases we discuss their classification, biochemical properties, the molecular basis of their substrate specificity, their catalytic mechanism, and evolutionary significance.

    更新日期:2019-11-01
  • Microbiological risk assessment in stem cell manipulation.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2008-02-09
    Augusto Pessina,Arianna Bonomi,Carolina Baglio,Loredana Cavicchini,Francesca Sisto,Maria Grazia Neri,Laura Gribaldo

    Cell therapy based on the use of human stem cells is more complicated than transfusion or organ transplantation because cells may undergo many additional manipulations due to different treatments for isolation, expansion, differentiation, and other types of biological changes. These manipulations require the approval of regulatory agencies (other than ethical) and the processes must be monitored with more tests than the ones applied for minimally manipulated cells. The clinical safety and efficacy of transplanted cells depend on several factors such as homologous or non-homologous sources, extent of manipulation, and culture conditions. Moreover, the kind of information needed to address these issues may differ depending on whether the cells are to be used for tissue reconstruction or repair, or to recover metabolic functions. Also anatomical site, functional integration as well as duration of therapy, are crucial points that indirectly can influence safety. Many important assays have been suggested for environmental monitoring as well as to standardize microbiological controls in stem cell banks to prevent contamination. In order to guarantee safety two main aspects must be considered: one is related to the source of cells (the donor) and the other is depending on cell collection and processing. In this review we critically analyze the steps of the processes (from collection to banking) and consider the main factors involved in the clinical research (continuously in evolution) by suggesting a standardized facsimile form to use in the laboratory for the assessment of the microbiological risk related to the cell manipulations.

    更新日期:2019-11-01
  • The brucellae and their success as pathogens.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2007-11-23
    Humberto Guerra

    Brucellae are tiny, aerobic, slow growing, catalase and oxidase positive Gram negative coccobacilli or small rods, which may reach man through exposure to tissues of mammalian hosts via cuts or aerosols, or as food infections mostly through dairy products. As parasites brucellae are extraordinarily successful, causing very long-lasting infections in all mammalian social animals, such as ungulates, canids, and rodents; recently they have been found to also cause disease in pinnipeds and cetaceans. Brucellae as members of the alpha Proteobacteria, have suffered major losses of genomic material as they adapted to their facultative intracellular parasite role, and are able to initiate infection with minimal disturbance of the innate immune system, thus reaching a privileged intracellular niche where they multiply. Brucellae are likely to be among the toughest organisms to control through public health and agricultural policies, even involving detection-slaughter strategies.

    更新日期:2019-11-01
  • Lyssaviruses.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2007-11-23
    Louis H Nel,Wanda Markotter

    Lyssaviruses are the etiological agents of rabies, one of the oldest viral diseases known to man and a disease that has persisted over many centuries. Together with sound diagnostic methods and efficacious vaccines--both of which had been available for many decades, an understanding of the epidemiology of the disease have enabled its control and even elimination in some specific reservoir species in North America and Western Europe. However, worldwide rabies still radiates into new host species and geographical domains and has become vastly underestimated throughout the developing world through lack of awareness, apathy and poor surveillance. As a result, this disease is now more of a global public and veterinary health threat than it has ever been.

    更新日期:2019-11-01
  • The human/animal interface: emergence and resurgence of zoonotic infectious diseases.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2007-11-23
    Michael Greger

    Emerging infectious diseases, most of which are considered zoonotic in origin, continue to exact a significant toll on society. The origins of major human infectious diseases are reviewed and the factors underlying disease emergence explored. Anthropogenic changes, largely in land use and agriculture, are implicated in the apparent increased frequency of emergence and re-emergence of zoonoses in recent decades. Special emphasis is placed on the pathogen with likely the greatest zoonotic potential, influenza virus A.

    更新日期:2019-11-01
  • Ecological origins of novel human pathogens.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2007-11-23
    Mark Woolhouse,Eleanor Gaunt

    A systematic literature survey suggests that there are 1399 species of human pathogen. Of these, 87 were first reported in humans in the years since 1980. The new species are disproportionately viruses, have a global distribution, and are mostly associated with animal reservoirs. Their emergence is often driven by ecological changes, especially with how human populations interact with animal reservoirs. Here, we review the process of pathogen emergence over both ecological and evolutionary time scales by reference to the "pathogen pyramid." We also consider the public health implications of the continuing emergence of new pathogens, focusing on the importance of international surveillance.

    更新日期:2019-11-01
  • Microbial production of C13-norisoprenoids and other aroma compounds via carotenoid cleavage.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2007-07-27
    E Rodríguez-Bustamante,S Sánchez

    Carotenoids are important precursors of a variety of compounds: the C(20)-retinoids, the C(15)-phytohormones, and the C(9)- to C(13)-aromas. Among the last type, C(13)-carotenoid-derived compounds (norterpenoids/norisoprenoids) such as ionones and damascones, constitute an essential aroma note in tea, grapes, roses, tobacco, and wine. Extraction of carotenoid-derived aroma compounds from plant sources is not economically realistic or considerably expensive. The biotechnological production of aroma compounds represents a feasible alternative and offers the production of enantiomerically pure molecules which can be labeled as "natural." To date, research in the production of ionones or the C(10)-compound, safranal, has mainly been focused on plant dioxygenases that cleave carotenoids in the positions between carbons 9 and 10 (9'-10') or 7 and 8 (7'-8'), respectively. Although relatively little is known about the microbial conversion of carotenoids into compounds with aroma due to the well known advantages of manipulating microorganisms, the aim of this work is to review the current state of the research in microbial production of norisoprenoids and other aroma compounds derived from carotenoid cleavage.

    更新日期:2019-11-01
  • Microbial extremophiles at the limits of life.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2007-07-27
    Elena V Pikuta,Richard B Hoover,Jane Tang

    Prokaryotic extremophiles were the first representatives of life on Earth and they are responsible for the genesis of geological structures during the evolution and creation of all currently known ecosystems. Flexibility of the genome probably allowed life to adapt to a wide spectrum of extreme environments. As a result, modern prokaryotic diversity formed in a framework of physico-chemical factors, and it is composed of: thermophilic, psychrophilic, acidophilic, alkaliphilic, halophilic, barophilic, and radioresistant species. This artificial systematics cannot reflect the multiple actions of different environmental factors since one organism could unite characteristics of several extreme-groups. In this review we show the current status of studies in all fields of extremophiles and summarize the limits of life for different species of microbial extremophiles. We also discuss the finding of extremophiles from unusual places such as soils, and briefly review recent studies of microfossils in meteorites in the context of the significance of microbial extremophiles to Astrobiology.

    更新日期:2019-11-01
  • The seminal literature of anthrax research.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2007-07-27
    Ronald N Kostoff,Stephen A Morse,Serkan Oncu

    A chronically weak area in research papers, reports, and reviews is the complete identification of seminal background documents that formed the building blocks for these papers. A method for systematically determining these seminal references is presented. Citation-Assisted Background (CAB) is based on the assumption that seminal documents tend to be highly cited. Application of CAB to the field of Anthrax research is presented. While CAB is a highly systematic approach for identifying seminal references, it is not a substitute for the judgment of the researchers, and serves as a supplement.

    更新日期:2019-11-01
  • A new model for the transmission of Helicobacter pylori: role of environmental reservoirs as gene pools to increase strain diversity.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2007-07-27
    N F Azevedo,N Guimarães,C Figueiredo,C W Keevil,M J Vieira

    Twenty-five years after the first successful cultivation and isolation of Helicobacter pylori, the scientific community is still struggling to understand the way(s) this bacterium is transmitted among the human population. Here, both epidemiologic and microbiologic evidence addressing this matter is reviewed and explored to conclude that most H. pylori successful colonizations are derived from direct person-to-person contact and that even though exposure of humans to H. pylori from environmental sources is a very common event, in most occasions the host is able to fight off infection. In addition, under a new model developed here, we propose that the near elimination of environmental reservoirs is the main responsible for the lower prevalence observed in the more industrialized countries by acting on two levels: by decreasing the number of direct infections and by diminishing the number of intraspecies recombination events for producing strain variation within H. pylori.

    更新日期:2019-11-01
  • Phosphoinositide signaling in unicellular eukaryotes.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2007-07-27
    Irina V Shemarova

    The review considers the up to date achievements in the role of membrane phosphoinositides and keys enzymes of the lipid branch of the phosphoinositide signal pathway (PI-pathway) in unicellular eukaryotes. Particular attention is paid to mechanisms of phospholipase C (PLC) activation and the PLC interaction both with cell surface receptors and with the effector cytoplasm targets. The role of protein kinase C (PKC) in intracellular signaling and the relationship of the PI-pathway key enzymes with protein tyrosine kinases (PTK)-signaling and cAMP-protein kinase A (PKA) pathway are discussed.

    更新日期:2019-11-01
  • Acetoin metabolism in bacteria.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2007-06-15
    Zijun Xiao,Ping Xu

    Acetoin is an important physiological metabolite excreted by many microorganisms. The excretion of acetoin, which can be diagnosed by the Voges Proskauer test and serves as a microbial classification marker, has its vital physiological meanings to these microbes mainly including avoiding acification, participating in the regulation of NAD/NADH ratio, and storaging carbon. The well-known anabolism of acetoin involves alpha-acetolactat synthase and alpha-acetolactate decarboxylase; yet its catabolism still contains some differing views, although much attention has been focused on it and great advances have been achieved. Current findings in catabolite control protein A (CcpA) mediated carbon catabolite repression may provide a fuller understanding of the control mechanism in bacteria. In this review, we first examine the acetoin synthesis pathways and its physiological meanings and relevancies; then we discuss the relationship between the two conflicting acetoin cleavage pathways, the enzymes of the acetoin dehydrogenase enzyme system, major genes involved in acetoin degradation, and the CcpA mediated acetoin catabolite repression pathway; in the end we discuss the genetic engineering progresses concerning applications. To date, this is the first integrated review on acetoin metabolism in bacteria, especially with regard to catabolic aspects. The apperception of the generation and dissimilation of acetoin in bacteria will help provide a better understanding of microbial strategies in the struggle for resources, which will consequently better serve the utilization of these microbes.

    更新日期:2019-11-01
  • Botulism diagnostics: from clinical symptoms to in vitro assays.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2007-06-15
    Shuowei Cai,Bal Ram Singh,Shashi Sharma

    Botulinum neurotoxin (BoNT), which cause the deadly neuroparalytic disease, botulism, is the most toxic substance known to man. BoNT can be used as potential bioterrorism agents, and therefore, pose great threat to national security and public health. Rapid and sensitive detection of BoNTs using molecular and biochemical techniques is an essential component in the diagnosis of botulism, and is yet to be achieved. The most sensitive and widely accepted assay method for BoNTs is mouse bioassay, which takes 4 days to complete. This clearly can not meet the need for clinical diagnosis of botulism, botulinum detection in field conditions, and screening of large scale samples. Consequently, the clinical diagnosis of botulism relies on the clinical symptom development, thus limiting the effectiveness of antitoxin treatment. In response to this critical need, many in vitro methods for BoNT detection are under development. This review is focused on recently developed in vitro detection methods for BoNTs, and emerging new technologies with potential for sensitive and rapid in vitro diagnostics for botulism.

    更新日期:2019-11-01
  • Survival and inactivation of Arcobacter spp., a current status and future prospect.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2007-06-15
    Libor Cervenka

    Arcobacter spp. has been isolated from food of animal origin (particularly meats) and from various kind of water. Despite its phylogenetically related neighbor Campylobacter, Arcobacter is regarded as an emerging foodborne pathogen. Since Arcobacter differs in its phenotypic characteristics, the physical and chemical treatments designed for elimination of campylobacters from food and environment needs to be verified. This review focuses on the occurrence, and mainly on susceptibility to various physical and chemical treatments for inactivation of Arcobacter spp. The existing studies have been critically discussed and new challenges were proposed for further studies.

    更新日期:2019-11-01
  • Issues for microbial regulation: Aeromonas as a model.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2007-04-25
    Stephen C Edberg,Frederick A Browne,Martin J Allen

    The decision by public health agencies to regulate specific microorganisms that may be found in drinking water can only be made if specific criteria find that a microorganism poses a health risk. These criteria should include: (1) there is a clinical history of an organism causing disease from the ingestion of drinking water; (2) there is epidemiological evidence that drinking water rather than food or other vectors is a major source of disease; (3) there is sufficient evidence that the target organism, if found in water, possesses virulence factors capable of causing disease in humans; (4) there is sufficient evidence that the target organism is not readily removed or inactivated by multi-barrier conventional water treatment process (e.g., coagulation-filtration-disinfection); (5) there is sufficient evidence that the target organism, if surviving conventional treatment, will be viable, virulent, and present in sufficient numbers to cause disease; (6) there are robust analytical methods for the target organism which have acceptable sensitivity, specificity, and reproducibility to measure accurately the presence of the target organism in treated water; and (7) the performance criteria of analytical method(s) for the target organism have been certified by the appropriate public health agency, and there is intra-laboratory field-test performance data to base this certification.

    更新日期:2019-11-01
  • The non-O157 shiga-toxigenic (verocytotoxigenic) Escherichia coli; under-rated pathogens.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2007-04-25
    Karl A Bettelheim

    Following a brief review of the ecology of Escherichia coli in general, the role of Shiga-Toxigenic (Verocytotoxigenic) E. coli (STEC) as pathogens is addressed. While STEC belonging to the serogroup O157 have been extensively studied and shown to be involved in many cases and outbreaks of human disease, the importance of STEC belonging to other serogroups has not been recognized as much. This review addresses the problems associated with these pathogens, demonstrating that increasing the awareness of them is a major part of the problem. This review then demonstrates how widespread isolations especially from food animals and human disease have been, discussing in particular STEC belonging to serogroups O8, O26, O103, O111, O113 and O128. The animal host-specificity of these STEC is also reviewed. In conclusion some methods of improving isolation of these pathogens is addressed.

    更新日期:2019-11-01
  • Leprosy and tuberculosis: an insight-review.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2007-04-25
    Tahziba Hussain

    A quick glance at this review article provides an insight into the common and different features of M. leprae and M. tuberculosis and the diseases caused by these organisms. Table I provides the popular names, history, stigma, description of the disease, clinical features, classification and the types of disease manifestations, who are affected, Signs and Symptoms, Clinical examination, treatment regimens, reactions, relapses, immunity, infectiousness, risk groups, deformities, sequelae, transmission, prevention, complications, vaccination, laboratory studies, days of importance for both the diseases. Table II provides information regarding the causative organisms, M. leprae and M. tuberculosis, their size, genome, protein coding region, lost genes, pseudogenes, classification, predilection, incubation period, ecology, cell structure, metabolism, resistance, bacterial index, growth in vitro, experimental animals, etc. Table III provides figures of M. leprae and M. tuberculosis, their genome, Lepromin and Tuberculin testing, Global scenario, Indian scenario, colonies of M. leprae and M. tuberculosis, drugs for treatment of tuberculosis and leprosy (MDT blister pack), and so on.

    更新日期:2019-11-01
  • Regulation of sugar catabolism in Lactococcus lactis.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2007-04-25
    Magdalena Kowalczyk,Jacek Bardowski

    The increasing number of genomic and post-genomic studies on Gram-positive organisms and especially on lactic acid bacteria brings a lot of information on sugar catabolism in these bacteria. Like for many other bacteria, glucose is the most preferred source of carbon and energy for Lactococcus lactis. Other carbon sources can induce their own utilization in the absence of well-metabolized sugar. These processes engage numbers of genes and undergo complex mechanisms of regulation. In this review, we discuss various biochemical and genetic control mechanisms involved in sugar catabolism, like regulation by repressors, activators, antiterminators or carbon catabolite repression control.

    更新日期:2019-11-01
  • The contribution of cytolethal distending toxin to bacterial pathogenesis.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2006-11-25
    James L Smith,Darrell O Bayles

    Cytolethal distending toxin (CDT) is a bacterial toxin that initiates a eukaryotic cell cycle block at the G2 stage prior to mitosis. CDT is produced by a number of bacterial pathogens including: Campylobacter species, Escherichia coli, Salmonella enterica serovar Typhi, Shigella dystenteriae, enterohepatic Helicobacter species, Actinobacillus actinomycetemcomitans (the cause of aggressive periodontitis), and Haemophilus ducreyi (the cause of chancroid). The functional toxin is composed of three proteins; CdtB potentiates a cascade leading to cell cycle block, and CdtA and CdtC function as dimeric subunits, which bind CdtB and delivers it to the mammalian cell interior. Once inside the cell, CdtB enters the nucleus and exhibits a DNase I-like activity that results in DNA double-strand breaks. The eukaryotic cell responds to the DNA double-strand breaks by initiating a regulatory cascade that results in cell cycle arrest, cellular distension, and cell death. Mutations in CdtABC that cause any of the three subunits to lose function prevent the bacterial cell from inducing cytotoxicity. The result of CDT activity can differ somewhat depending on the eukaryotic cell types affected. Epithelial cells, endothelial cells, and keratinocytes undergo G2 cell cycle arrest, cellular distension, and death; fibroblasts undergo G1 and G2 arrest, cellular distension, and death; and immune cells undergo G2 arrest followed by apoptosis. CDT contributes to pathogenesis by inhibiting both cellular and humoral immunity via apoptosis of immune response cells, and by generating necrosis of epithelial-type cells and fibroblasts involved in the repair of lesions produced by pathogens resulting in slow healing and production of disease symptoms. Thus, CDT may function as a virulence factor in pathogens that produce the toxin.

    更新日期:2019-11-01
  • Candida species adhesion to oral epithelium: factors involved and experimental methodology used.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2006-11-25
    Mariana Henriques,Joana Azeredo,Rosário Oliveira

    Due to the increasing prevalence and emergence of Non-Candida albicans Candida (NCAC) species, especially in immunosupressed patients, it is becoming urgent to deepen the current knowledge about virulence factors of these species. Adhesion of cells to epithelium is considered one of the major virulence factors of Candida species. However, relatively little is known concerning the adhesion mechanisms of NCAC species to epithelium, as well as about the factors affecting the adhesion process. This review focuses both the mechanisms that regulate the adhesion interactions and the factors involved and the description of the experimental methodology that has been used to perform the adhesion assays.

    更新日期:2019-11-01
  • High-pressure homogenization as a non-thermal technique for the inactivation of microorganisms.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2006-11-25
    Ann M J Diels,Chris W Michiels

    In the pharmaceutical, cosmetic, chemical, and food industries high-pressure homogenization is used for the preparation or stabilization of emulsions and suspensions, or for creating physical changes, such as viscosity changes, in products. Another well-known application is cell disruption of yeasts or bacteria in order to release intracellular products such as recombinant proteins. The development over the last few years of homogenizing equipment that operates at increasingly higher pressures has also stimulated research into the possible application of high-pressure homogenization as a unit process for microbial load reduction of liquid products. Several studies have indicated that gram-negative bacteria are more sensitive to high-pressure homogenization than gram-positive bacteria supporting the widely held belief that high-pressure homogenization kills vegetative bacteria mainly through mechanical disruption. However, controversy exists in the literature regarding the exact cause(s) of cell disruption by high-pressure homogenization. The causes that have been proposed include spatial pressure and velocity gradients, turbulence, cavitation, impact with solid surfaces, and extensional stress. The purpose of this review is to give an overview of the existing literature about microbial inactivation by high-pressure homogenization. Particular attention will be devoted to the different proposed microbial inactivation mechanisms. Further, the different parameters that influence the microbial inactivation by high-pressure homogenization will be scrutinized.

    更新日期:2019-11-01
  • Diversity of the parachlamydiae in the environment.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2006-11-25
    Daniele Corsaro,Danielle Venditti

    Chlamydiae are obligate intracellular bacteria, parasites of a variety of eukaryotes ranging from amoebae to humans. Among them, the family Parachlamydiaceae comprises endosymbionts of amoebae, mainly Acanthamoeba, currently investigated as emerging pathogens of humans and other vertebrates. 16S rDNA-based PCR culture-independent studies in environmental samples have demonstrated the presence of Chlamydiales in various types of nonmedical habitats. Here we reviewed the biology of the Parachlamydiaceae, and more particularly those studies reporting molecular evidences for their presence in the environment, with a re-analysis of the 16S rDNA phylotypes.

    更新日期:2019-11-01
  • Amino acid catabolic pathways of lactic acid bacteria.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2006-08-09
    María Fernández,Manuel Zúñiga

    Lactic acid bacteria (LAB) constitute a diverse group of Gram positive obligately fermentative microorganisms which include both beneficial and pathogenic strains. LAB generally have complex nutritional requirements and therefore they are usually associated with nutrient-rich environments such as animal bodies, plants and foodstuffs. Amino acids represent an important resource for LAB and their utilization serves a number of physiological roles such as intracellular pH control, generation of metabolic energy or redox power, and resistance to stress. As a consequence, the regulation of amino acid catabolism involves a wide set of both general and specific regulators and shows significant differences among LAB. Moreover, due to their fermentative metabolism, LAB amino acid catabolic pathways in some cases differ significantly from those described in best studied prokaryotic model organisms such as Escherichia coli or Bacillus subtilis. Thus, LAB amino acid catabolism constitutes an interesting case for the study of metabolic pathways. Furthermore, LAB are involved in the production of a great variety of fermented products so that the products of amino acid catabolism are also relevant for the safety and the quality of fermented products.

    更新日期:2019-11-01
  • Streptococcus pneumoniae protein vaccine candidates: properties, activities and animal studies.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2006-08-09
    Stanley S Tai

    Streptococcus pneumoniae is a causative agent for community acquired pneumonia, bacteremia, acute otitis media, and meningitis. Recent emergence of multi-drug resistant clinical isolates prompts the need of effective vaccine for the prevention of disease. The licensed polysaccharide-based pneumococcal vaccines only elicit protective antibodies against the infection of serotypes that are included in the vaccine. To broaden the protection, the use of pneumococcal proteins will be a feasible and preferable alternative. This communication provides a review on the biochemical properties of these protein candidates, their immunization results in animal studies, and perspectives on the development of protein-based pneumococcal vaccine.

    更新日期:2019-11-01
  • Cyanobacteria metal interactions: requirements, toxicity, and ecological implications.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2006-08-09
    Mafalda S Baptista,M Teresa Vasconcelos

    The environmental health-related relevance of cyanobacteria is primarily related to their ability to produce a wide range of toxins, which are known to be hazardous to many organisms, including human beings. The occurrence of cyanobacterial blooms has been related to eutrophic surface water. In the bloom-forming process the levels of phosphorus and nitrogen have been well documented but information regarding concentrations of other chemicals (inorganic, organo-metallic, and organic) is still incipient. Several contaminants, like trace metals, elicit a variety of acute and chronic toxicity effects, but cyanobacteria also have the capability to accumulate, detoxify, or metabolize such substances, to some extent. The role of cyanobacterial exudates has been proved a means of both nutrient acquisition and detoxification. In addition, cyanobacteria are effective biological metal sorbents, representing an important sink for metals in aquatic environment. Understanding the fundamental physicochemical mechanisms of trace metal bio-uptake by cyanobacteria in natural systems is a step towards identifying under what conditions cyanobacterial growth is favored and to ascertain the mechanisms by which blooms (and toxin production) are triggered. In this review the cyanobacterial interactions with metals will be discussed, focusing on freshwater systems.

    更新日期:2019-11-01
  • Bioconversions of ferulic acid, an hydroxycinnamic acid.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2006-08-09
    Sindhu Mathew,T Emilia Abraham

    Ferulic acid is the most abundant hydroxycinnamic acid in the plant world and is ester linked to arabinose, in various plant polysaccharides such as arabinoxylans and pectins. It is a precursor to vanillin, one of the most important aromatic flavor compound used in foods, beverages, pharmaceuticals, and perfumes. This article presents an overview of the various biocatalytic routes, focusing on the relevant biotransformations of ferulic acid using plant sources, microorganisms, and enzymes.

    更新日期:2019-11-01
  • Resilience of microbial systems towards disturbances.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2006-07-21
    S Botton,M van Heusden,J R Parsons,H Smidt,N van Straalen

    In this paper we aim at summarizing the current definitions of resilience in systems ecology with particular attention towards microbial systems. The recent advances of biomolecular techniques have provided scientists with new tools to investigate these systems in greater detail and with higher resolution. Therefore existing concepts and hypotheses have been revisited and discussed with respect to their applicability for ecosystems ruled by microbial processes. This review has also led to some reflections on the suitability of the term "resilience" as a general goal in environmental policies.

    更新日期:2019-11-01
  • Role of poly-galacturonase inhibiting protein in plant defense.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2006-07-01
    Cuixia Di,Manxiao Zhang,Shijian Xu,Tuo Cheng,Lizhe An

    Polygalacturonase-inhibiting proteins (PGIPs) are plant proteins believed to play an important role in the defense against plant pathogen fungals. PGIPs are glycoproteins located in plant cell wall which reduce the hydrolytic activity of polygalacturonases (PGs), limit the growth of plant pathogens, and also elicit defense responses in plant. Furthermore, PGIPs belong to the super family of leucine reach repeat (LRR) proteins which also include the products of several plant resistance genes. Many of the studies show the PGIP properties, molecular characteristics, and PGIP gene expression induced by some elicitors. Some of the studies review individual PGIP gene expression in different signal transduction pathways. This article summarizes the properties, different signal transduction mechanisms, detecting methods, transgenic plants, and function of PGIP. It also presents PGIP gene expression in different stages of maturity, tissues, and varieties. The review especially reports the particular PGIP gene expression induced by different biotic and abiotic stresses, offers some questions, and prospects the future study, which are needed in order to develop efficient strategies for disease-resistant plants. They may be useful for genetic engineering to obtain transgenic plants with increased tolerance to fungal infection, which decrease the use of insecticide.

    更新日期:2019-11-01
  • Unidirectional movement of flares of cells of Myxococcus xanthus.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2006-07-01
    Arthur L Koch

    Amongst other modes, Myxococcal cells move in swarms that are flares or columns of cells. It has been argued that this is a strategy allowing a large enough number of them to encounter food bacteria. Then, the combined large amount of extracellular lytic enzymes from the mass of cells can provide adequate nutrient resources from the food bacteria for all the myxococci of the swarm. However, how they move as a coherent column has not been adequately explained. Here based on the idea that a rare cell can experience a special mutation such that it moves only unidirectionally, a proposal to account for this aspect of Myxococcus cell movement is suggested. Although wild type individual organisms of this species engage in forward and back movements, a mutant cell that moves unidirectionally can bias the movement of associated wild type cells and lead to the formation of a column of cells, headed by such a unique mutated cell. The non-mutated cells follow along it is suggested because of the S-motility (or social motility) system. This may link them to this single unidirectionally moving mutant cell to give a coherent movement to the column. This proposed type of mutation back mutates to wild type and the column no longer functions as such and only wild-type cells are present.

    更新日期:2019-11-01
  • Environmental stress response in wine lactic acid bacteria: beyond Bacillus subtilis.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2006-07-01
    G Spano,S Massa

    Lactic acid bacteria (LAB) constitute a heterogeneous group of bacteria that are traditionally used to produce fermented foods. The industrialization of food transformations has increased the economical importance of LAB, as they play a crucial role in the development of the organoleptic and hygienic quality of fermented products. However, the strains selected for industrial purposes, should tolerate adverse conditions encountered in industrial processes, either during starter handling and storage (freeze-drying, freezing, or spray-drying) or during food processing in which abiotic stresses such as heat, cold, acidity, and high concentration of NaCl or ethanol are common. Wine LAB have to deal with several stresses including an acidic pH, a high alcoholic content, non optimal growth temperatures, and growth-inhibitory compounds such as fatty acids and tannins, originated from yeast and bacteria metabolism. Wine LAB have developed several mechanisms to escape or to tolerate wine conditions. They carry out a malolactic fermentation in this stressful environment. In addition to the regulation of the expression of specific genes, bacteria have evolved adaptive networks to face the challenges of a changing environment and to survive under conditions of stress. The so called Global Regulatory Systems control the simultaneous expression of a large number of genes in response to a variety of environmental stress factors. CIRCE sequences able to bind the HrcA repressor, sigma(B) dependent promoters and CtsR regulatory elements have been observed in several genes identified from wine LAB. Improved knowledge of regulators and a better understanding of LAB stress responses could constitute a basis of comparison with the well known model microorganisms, Escherichia coli and Bacillus subtilis. Moreover, it can provide an important insight into improving current industrial starter strains.

    更新日期:2019-11-01
  • IdeR in mycobacteria: from target recognition to physiological function.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2006-07-01
    Sarita Ranjan,Sailu Yellaboina,Akash Ranjan

    In mycobacteria, iron dependent transcription regulator (IdeR) regulates transcription of genes in response to iron levels. The IdeR regulated genes have been investigated mostly in M. tuberculosis, M. smegmatis, and in few of the other related species. Recent advances in crystal structure solution and computational as well as experimental identification of IdeR targets has provided insight into IdeR structure and function. Here in this review we take stock of current state of knowledge on IdeR and its targets to understand the underlying design of the IdeR regulon and its role in mycobacterial physiology.

    更新日期:2019-11-01
  • What non-proliferation policy for the Soviet anti-plague system?
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2006-04-14
    Sonia Ben Ouagrham-Gormley,Alexander Melikishvili,Raymond A Zilinskas

    This article analyzes the proliferation challenges posed by the Soviet AP system and discusses possible nonproliferation strategies to prevent these threats.

    更新日期:2019-11-01
  • The anti-plague system and the Soviet biological warfare program.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2006-04-14
    Raymond A Zilinskas

    The USSR possessed a unique national public health system that included an agency named "anti-plague system." Its mission was to protect the country from highly dangerous diseases of either natural or laboratory etiology. During the 1960s, the anti-plague system became the lead agency of a program to defend against biological warfare, codenamed Project 5. This responsibility grew and by the middle 1970s came to include undertaking tasks for the offensive biological warfare program, codenamed Ferment. This article describes the anti-plague system's activities relevant to both aspects of the Soviet Union's biological warfare program, offense and defense, and analyzes its contributions to each.

    更新日期:2019-11-01
  • Growth of the anti-plague system during the Soviet period.
    Crit. Rev. Microbiol. (IF 5.697) Pub Date : 2006-04-14
    Sonia Ben Ouagrham-Gormley

    The Anti-plague system experienced a dramatic expansion in Soviet times. From the dozen facilities created in the Russian Empire, it grew during the Soviet period to include over 100 facilities engaged in public health activities as well as BW-related work. This article describes how this highly responsive public health system, created to respond to natural outbreaks of dangerous diseases, became a critical adjunct to the Soviet BW program.

    更新日期:2019-11-01
Contents have been reproduced by permission of the publishers.
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