Candida tropicalis is an opportunistic human pathogen with an ability to cause superficial as well as systemic infections in immunocompromised patients. The formation of biofilm by C. tropicalis can cause dreadful and persistent infections which are difficult to treat due to acquired resistance. Presently, available anti-Candida drugs exhibit a high frequency of resistance, low specificity and toxicity at a higher dosage. In addition, the discovery of natural or synthetic anti-Candida drugs is slow paced and often does not pass clinical trials. Citral, a monoterpene aldehyde, has shown effective antimicrobial activities against various microorganisms. However, only few studies have elaborated the action of citral against the biofilm of C. tropicalis. In the present work, the aim was to study the fungicidal effect, differential expression of proteome and changes in extracellular matrix in response to the sub-lethal concentration (16 µg/mL) of citral. The administration of citral on C. tropicalis biofilm leads to a fungicidal effect. Furthermore, the differential expression of proteome has revealed twenty-five proteins in C. tropicalis biofilm, which were differentially expressed in the presence of citral. Among these, amino acid biosynthesis (Met6p, Gln1p, Pha2p); nucleotide biosynthesis (Xpt1p); carbohydrate metabolism (Eno1p, Fba1p, Gpm1p); sterol biosynthesis (Mvd1p/Erg19p, Hem13p); energy metabolism (Dnm1p, Coa1p, Ndk1p, Atp2p, Atp4p, Hts1p); oxidative stress (Hda2p, Gre22p, Tsa1p, Pst2p, Sod2p) and biofilm-specific (Adh1p, Ape1p, Gsp1p) proteins were identified. The overexpression of oxidative stress–related proteins indicates the response of biofilm cell to combating oxidative stress during citral treatment. Moreover, the upregulation of Adh1p is of particular interest because it subsidizes the biofilm inhibition through ethanol production as a cellular response. The augmented expression of Mvd1p/Erg19p signifies the effect of citral on ergosterol biosynthesis. The presence of citral has also shown an increment in hexosamine and ergosterol component in extracellular matrix of C. tropicalis biofilm. Hence, it is indicated that the cellular response towards citral acts through multifactorial processes. This study will further help in the interpretation of the effect of citral on C. tropicalis biofilm and development of novel antifungal agents against these potential protein targets.

热带念珠菌是一种机会性人类病原体，能够在免疫功能低下的患者中引起表面感染和全身感染。热带梭状芽孢杆菌形成的生物膜会导致可怕的持续感染，由于获得性抗性而难以治疗。目前，可用的抗念珠菌药物在较高剂量下表现出高频率的耐药性、低特异性和毒性。此外，天然或合成抗念珠菌药物的发现步伐缓慢，通常无法通过临床试验。柠檬醛是一种单萜醛，对各种微生物显示出有效的抗菌活性。然而，只有少数研究阐述了柠檬醛对生物膜的作用。C.热带。在目前的工作中，目的是研究柠檬醛在亚致死浓度（16 µg/mL）下的杀菌效果、蛋白质组的差异表达和细胞外基质的变化。在热带梭状芽孢杆菌生物膜上施用柠檬醛会产生杀真菌效果。此外，蛋白质组的差异表达揭示了热带假丝酵母中的 25 种蛋白质。生物膜，在柠檬醛存在下差异表达。其中，氨基酸生物合成（Met6p、Gln1p、Pha2p）；核苷酸生物合成（Xpt1p）；碳水化合物代谢（Eno1p、Fba1p、Gpm1p）；甾醇生物合成（Mvd1p/Erg19p，Hem13p）；能量代谢（Dnm1p、Coa1p、Ndk1p、Atp2p、Atp4p、Hts1p）；鉴定了氧化应激（Hda2p、Gre22p、Tsa1p、Pst2p、Sod2p）和生物膜特异性（Adh1p、Ape1p、Gsp1p）蛋白。氧化应激相关蛋白的过表达表明生物膜细胞在柠檬醛处理期间对抗氧化应激的反应。此外，Adh1p 的上调特别令人感兴趣，因为它通过乙醇产生作为细胞反应来补贴生物膜抑制。Mvd1p/Erg19p 的增强表达表明柠檬醛对麦角甾醇生物合成的影响。C.tropicalis生物膜。因此，表明对柠檬醛的细胞反应通过多因素过程起作用。该研究将进一步有助于解释柠檬醛对热带梭状芽孢杆菌生物膜的影响，以及开发针对这些潜在蛋白质靶点的新型抗真菌剂。