The present study deals with a current arising problem of landless farmers and a challenge in solving an age-long difficulty of silk farmers: feeding of larvae during rainy season. On feeding wet mulberry leaves, the mortality rate of larvae increases, as a result of which productivity decreases. Biogenic synthesized silver nanoparticles were found to be effective in preserving mulberry leaves at the post-harvest stage. A major threat during preservation is the decline in the protein content of leaves, putting a negative impact over productivity, as leaf protein content is a major contributor towards silk gland development. Another threat resides with the generation of excessive reactive oxygen species (ROS), causing cellular damage and thereby enhancing senescence. SDS (sodium dodecyl sulphate) gel analysis of mulberry leaf protein reflects the preservative potential of nanosilver solution. Leaves preserved in nanosilver solution showed gel banding pattern almost constant till the entire duration of preservation, i.e. for 7 days, and the banding pattern was more prominent and invariable than the banding pattern showed by leaf protein preserved in silver nitrate and distilled water. SDS banding pattern of silkworm larvae fed with nanosilver-preserved leaves appeared almost similar to that of larvae fed with fresh leaves, which also reflects a high preservative potential of nanosilver solution. Through isozyme profiling, superoxide dismutase (SOD) and catalase (CAT) activity was found to be active in both nanosilver-preserved mulberry leaves and silk gland of larvae fed with the same preserved leaves;also, this up-regulated peroxidase activity was observed in preserved leaves. Isozyme profiling reflects the presence of sufficient defensive activity to protect against damage caused by ROS accumulation. OHR-LCMS profiled proteins through string analysis detected involvement of photosynthesis-associated proteins and stress-inhibiting proteins, helping to prevent senescence and thus enhancing shelf life.

中文翻译：

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纳米银保藏桑叶及饲喂相同叶片的蚕幼虫的蛋白质谱研究

本研究解决了当前出现的无地农民问题，以及解决丝绸农民长期存在的难题的挑战：在雨季喂养幼虫。饲喂湿桑叶时，幼虫的死亡率增加，其结果是生产力降低。发现生物合成的银纳米颗粒在收获后的阶段可有效地保存桑叶。保存过程中的主要威胁是叶片中蛋白质含量的下降，这对生产率产生了负面影响，因为叶片蛋白质含量是蚕丝腺发育的主要因素。另一个威胁在于过量的活性氧（ROS）的产生，从而引起细胞损伤，从而增强衰老。桑叶蛋白的SDS（十二烷基硫酸钠）凝胶分析反映了纳米银溶液的防腐潜力。在纳米银溶液中保存的叶片在整个保存过程中（即7天）都显示出几乎恒定的凝胶条带模式，与在硝酸银和蒸馏水中保存的叶蛋白所显示的条带模式相比，条带模式更加突出和不变。饲喂纳米银保鲜叶片的家蚕幼虫的SDS谱带显示与饲喂新鲜叶片的幼虫几乎相似，这也反映了纳米银溶液的高防腐潜力。通过同工酶分析，发现超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性在纳米银保存的桑叶和用相同保存的叶饲喂的幼虫的丝腺中均具有活性；此外，在保留的叶子中观察到这种上调的过氧化物酶活性。同工酶分析表明存在足够的防御活性，可以防止由ROS积累引起的损害。通过字符串分析对OHR-LCMS进行分析的蛋白可以检测到光合作用相关蛋白和压力抑制蛋白的参与，从而有助于防止衰老，从而延长了保质期。