Periplaneta americana peptide decreases apoptosis of pig-ovary granulosa cells induced by H2O2 through FoxO1

Oxidative stress can induce apoptosis of granulosa cells and lead to follicular atresia, thereby reducing the number of pigs giving birth. The aim of this study was to investigate the protective effect of Periplaneta americana peptide (PAP) on the apoptosis of the granulosa cells of pig ovaries (PGCs) induced by hydrogen peroxide (H₂O₂) via FoxO1. PGCs were treated with H₂O₂ to establish a cell apoptosis model. Cell viability was measured using the cell counting kit-8 (CCK-8) assay, and cell apoptosis was detected using flow cytometry. The malondialdehyde (MDA) level and nitric oxide (NO) content were detected to reflect the oxidative stress. Western blotting, qRT-PCR and overexpression were undertaken to determine the expression of FoxO1 and caspase-3, and immunofluorescence was used to detect FoxO1 in the nucleus and cytoplasm. PGCs were treated with 100 μM H₂O₂ for 6 hr, which resulted in oxidative damage and apoptosis and an apoptosis rate for PGCs of 32.95%. Next, PGCs were treated with 400 μg/ml PAP for 24 hr to repair the apoptosis induced by H₂O₂. PAP improved cell viability in H₂O₂-stimulated PGCs, the increased MDA level and NO content caused by H₂O₂ stimulation were reversed and the apoptotic rate of PGCs was reduced. The qRT-PCR and Western blotting results indicated that PAP decreased the H₂O₂-induced apoptosis and the expression of FoxO1 and caspase-3 in PGCs. The effect of PAP was the same following FoxO1 overexpression. FoxO1 was expressed in the nucleus when stimulated by H₂O₂ or overexpression; however, it migrated to the cytoplasm following PAP treatment. PAP decreased the apoptosis of PGCs induced by H₂O₂ by regulating FoxO1 expression and nuclear translocation.     

虾肽肥料对酸性土壤的改良效果

[目的]针对热带地区土壤酸化和养分含量低的问题,探索一种适宜的土壤改良方法。[方法]研究了施用虾肽肥料对热带地区土壤p H与养分含量的影响。[结果]与单施虾肽土壤调理剂相比,虾肽土壤调理剂与虾肽根宝配合施用可提高土壤p H与土壤有机质、全氮、碱解氮、有效磷和速效钾等养分含量。[结论]虾肽土壤调理剂可以在热带地区用于土壤改良。     

猪轮状病毒VP7蛋白模拟表位的噬菌体展示技术筛选与鉴定

猪轮状病毒(Po RV)是引起仔猪腹泻的重要病原之一,其主要结构蛋白衣壳蛋白VP7可诱导机体产生中和抗体。文章以制备的抗Po RV VP7单克隆抗体(MAb)3B6作为靶分子,利用噬菌体十二肽库展示技术对其模拟表位进行筛选。四轮筛选后随机挑取阳性克隆扩增后进行ELISA鉴定,同时提取其基因组DNA测序,10个阳性噬菌体亲和肽拥有共同的外源肽序列"VPLGTDNGDIWV",而且与靶分子有很高亲和力。阳性噬菌体亲和肽与VP7蛋白进行序列比对,结果表明,十二肽中有4个氨基酸(第167位P、第178位T、第179位D和第184位W)与VP7蛋白167~184位氨基酸有一定的相似性。竞争抑制ELISA证明亲和多肽降低Po RV与抗VP7单克隆抗体之间的作用,病毒竞争抑制试验表明亲和多肽可以竞争性地抑制Po RV感染细胞。因此由这4个氨基酸构成的基序很有可能作为猪轮状病毒VP7蛋白的一个模拟表位。     

花生非淀粉多糖和抗氧化肽同步提取技术研究

研究米曲霉和酿酒酵母混合固态发酵热榨花生粕同步提取花生非淀粉多糖和抗氧化肽,为花生粕的高值化利用提供理论基础。以发酵产物的可溶性氮浓度、1,1-二苯基苦基苯肼(DPPH)自由基清除率、羟自由基清除率和非淀粉多糖得率为考察指标,研究了菌种比例、接种量、营养盐溶液量、发酵温度、发酵时间、水浴温度和水浴时间对发酵效果的影响,确定最佳工艺条件为:菌种比例1∶2,接种量3mL,营养盐溶液添加量30mL,发酵温度33℃,发酵时间42h,水浴温度40℃,水浴时间6h。此工艺下发酵产物的可溶性氮浓度为46.32mg/mL、DPPH自由基清除率为71.90%、羟自由基清除率为96.96%、非淀粉多糖得率为4.36%。发酵产物经乙醇沉淀和超滤分离得到的花生非淀粉多糖和抗氧化肽产品具有清除自由基、抑制脂质过氧化、金属离子螯合力和还原力等4大类抗氧化活性。     

苏云金芽胞杆菌BRC-HZP7杀虫晶体蛋白多样性分析

分离自武夷山土壤的苏云金芽胞杆菌BRC-HZP7菌株对小菜蛾和甜菜夜蛾幼虫有较好的毒杀作用.对该菌株进行了生理生化测定、cry基因的PCR-RFLP检测,以及通过SDS-PAGE检测晶体蛋白,并对蛋白点进行肽段指纹图谱鉴定.结果表明该菌株含有cry1Aa、cry1 Ba、cry1 Ia、cry2Ab、cry2Ac、cr...     

Chemical Synthesis and Structure-Activity Relationship Study Yield Desotamide a Analogues with Improved Antibacterial Activity

Desotamides A, a cyclohexapeptide produced by the deep-sea-derived Streptomyces scopuliridis SCSIO ZJ46, displays notable antibacterial activities against strains of Streptococcus pnuemoniae, Staphylococcus aureus, and methicillin-resistant Staphylococcus epidermidis (MRSE). In this study, to further explore its antibacterial potential and reveal the antibacterial structure-activity relationship of desotamides, 13 cyclopeptides including 10 new synthetic desotamide A analogues and wollamides B/B1/B2 were synthesized and evaluated for their antibacterial activities against a panel of Gram-positive and -negative pathogens. The bioactivity data reveal that residues at position II and VI greatly impact antibacterial activity. The most potent antibacterial analogues are desotamide A4 (13) and A6 (15) where l-allo-Ile at position II was substituted with l-Ile and Gly at position VI was simultaneously replaced by d-Lys or d-Arg; desotamides A4 (13) and A6 (15) showed a 2–4-fold increase of antibacterial activities against a series of Gram-positive pathogens including the prevalent clinical drug-resistant pathogen methicillin-resistant Staphylococcus aureus (MRSA) with MIC values of 8–32 μg/mL compared to the original desotamide A. The enhanced antibacterial activity, broad antibacterial spectrum of desotamides A4 and A6 highlighted their potential as new antibiotic leads for further development.     

革胡子鲶生长激素成熟肽cDNA克隆及其在大肠杆菌中的表达

[目的]构建革胡子鲶生长激素基因原核表达体系。[方法]采用PCR方法,扩增得到了革胡子鲶生长激素基因成熟肽的cDNA序列,将该序列克隆至原核表达载体pRSET-A,构建重组质粒pRSET-mGH,并在大肠杆菌BL21(DE3)pLysS中进行表达。[结果]革胡子鲶生长激素成熟肽cDNA序列全长534 bp,编码1个由178个氨基酸残基组成的生长激素成熟肽,分子量为20.28 kDa,等电点为5.93。SDS-PAGE和Western blot分析表明,表达的目的融合蛋白分子量为27.41 kDa,主要以非可溶性的包涵体形式存在于菌体沉淀中。目的融合蛋白的表达量高达细菌沉淀蛋白总量的36.8%。[结论]该研究为革胡子鲶生长激素的产业化开发和应用奠定了基础。     

大豆降压肽的生产工艺研究

应用4种蛋白酶酶解大豆分离蛋白,研究其水解效果和降压活性。实验选定碱性蛋白酶为生产大豆降压肽的最适酶,并对其酶解条件进行了优化,确定生产大豆降压肽的最佳条件为：温度60℃,pH8.0,底物浓度4%,碱性蛋白酶浓度4%,水解度14.4%,优化后的ACE抑制率可达到84.1%。     

利用噬菌体随机肽库筛选胰腺癌特异性血清标志物

目的探讨利用噬菌体随机肽库筛选胰腺癌特异性血清标志物的可行性。方法纯化40例正常人和40例首次确诊的胰腺癌患者的血清免疫球蛋白,进行3轮噬菌体随机肽库的亲和筛选,并随机挑选20个克隆进行阳性鉴定,对阳性克隆进行DNA测序和对比分析。结果通过正常对照的阴性排除和3轮亲和筛选,噬菌体随机12肽回收率提高了500倍。随机挑选的20个克隆中有10个阳性克隆,经DNA测序分析获得4条多肽。阳性克隆的敏感性为100%,特异性为95%,阳性预测值为95.2%,阴性预测值为100%,准确性为97.5%。结论利用噬菌体随机肽库能够成功筛选出胰腺癌患者特异性血清标志物。     

以合成肽为抗原建立口蹄疫病毒非结构蛋白抗体检测ELISA试剂盒

【目的】建立合成多肽抗原检测FMD NSP抗体的ELISA方法。【方法】固相法合成特异性FMDV NSP B细胞表位肽,将其偶联在BSA载体蛋白上,作为抗原包被在ELISA板上,制备检测抗FMDV NSP抗体的ELISA试剂盒,并对该试剂盒进行方法考核。【结果】抗原包被浓度选择2.5μg·mL-1;检测199份血清标本,与美国UBI商品试剂盒符合率达到96.48%,与国产3ABC ELISA比较,符合率为97.48%,显示极好的一致性。【结论】该合成肽ELISA试剂盒可以用以检测NSP抗体,从而鉴别FMD的自然感染与疫苗免疫,试剂盒特异性强,重复性好、稳定性高,操作简便。