内毒素对仔鸡血浆SOD活性及MDA水平的影响

为了探讨大肠埃希菌O55∶B5的内毒素(LPS)对仔鸡的损伤机理,将168只仔鸡随机分成4组(n=42),即对照组,100 mg/kgLPS组,200 mg/kg LPS组,300 mg/kg LPS组。灌服内毒素后,分别于2,4,8,12,24,48 h和72 h处死鸡(各时间点均为6只),测定血浆SOD活性和MDA浓度。结果表明,与对照组相比,各剂量组鸡血浆SOD活性均明显降低,MDA含量均明显升高(P<0.05)。且各剂量组之间SOD活性随攻毒剂量的增加而降低,随时间的延长先降低后升高;MDA含量随攻毒剂量的增加而升高,随时间的延长先升高后降低。表明一定量内毒素能诱发鸡体内氧自由基的产生,显著降低机体中SOD的活性和提高MDA的含量。     

乡村旅游综合发展优势及协调性研究——以华中地区乡村旅游重点村为例

乡村旅游是实现乡村振兴,推动乡村高质量发展的重要途径。为促进乡村旅游的高质量发展,本研究以华中地区124个乡村旅游重点村为研究对象,运用地理探测器量化多个影响因素对华中地区乡村旅游重点村空间分布的影响效果,构建综合优势度模型评价华中地区乡村旅游综合优势度,并结合重点村分布和综合优势度分布构建耦合协调度模型,以评估乡村旅游重点村发展的协调效果。研究结果表明：1）华中地区乡村旅游重点村呈现多核心的集聚分布,受多维影响因素综合影响,各因素间协同影响作用突出;2）综合优势度分析显示,华中地区乡村旅游综合发展优势总体上表现为河南省＞湖北省＞湖南省,与重点村空间分布高度耦合,且耦合协调类型与综合优势度成正相关;3）乡村旅游重点村的发展优势受各因素协调效果的制约,资源禀赋是选址的首要考虑指标,而交通条件是持续发展的必要条件。本研究可为乡村旅游创新提质和产业升级提供理论依据和实践经验。     

小型南瓜棚室高产栽培技术

南瓜品种类型多样,不同品种南瓜高产栽培技术不同,现就小型南瓜品种棚室高产栽培技术进行阐述.     

中国西部茶业的现状和可持续发展之路

中国西部茶区包括云南、四川、贵州、广西、重庆、陕西、甘肃、西藏等省(市、区),自改革开放特别是国家实施西部大开发战略以来,茶叶发展迅速,2004年西部茶叶种植面积已超过全国总面积的1/3,茶叶产量约为全国总产量的30%,产值约为全国总产值的1/4,茶叶出口快速增长.     

浅析我国植物检疫领域标准样品研究现状

本文介绍了标准样品研制工作在我国植物检疫领域的发展历程,梳理分析了已发布/立项标准样品的相关数据,结合作者单位在该领域研制标准样品实践经验,对植物检疫领域标准样品存在的问题进行了讨论,以供今后工作参考.     

新形势下纵深推进长汀水土流失治理的实践与探索

近年来,长汀县水土流失治理取得了关键性胜利,规模化成片治理基本结束.随着治理工作向纵深推进,显现出治理主体单一、流失斑块分散、治理资金不足、成效亮点不足以及治理成果巩固难等突出问题.为补齐治理短板,2019年以来,长汀县以项目化推进水土流失精准治理深层治理为抓手,强化工作举措,推动全县水土流失治理取得了决定性胜利,持续...     

A Novel Gelatinase from Marine Flocculibacter collagenilyticus SM1988: Characterization and Potential Application in Collagen Oligopeptide-Rich Hydrolysate Preparation

Although the S8 family in the MEROPS database contains many peptidases, only a few S8 peptidases have been applied in the preparation of bioactive oligopeptides. Bovine bone collagen is a good source for preparing collagen oligopeptides, but has been so far rarely applied in collagen peptide preparation. Here, we characterized a novel S8 gelatinase, Aa2_1884, from marine bacterium Flocculibacter collagenilyticus SM1988^T, and evaluated its potential application in the preparation of collagen oligopeptides from bovine bone collagen. Aa2_1884 is a multimodular S8 peptidase with a distinct domain architecture from other reported peptidases. The recombinant Aa2_1884 over-expressed in Escherichia coli showed high activity toward gelatin and denatured collagens, but no activity toward natural collagens, indicating that Aa2_1884 is a gelatinase. To evaluate the potential of Aa2_1884 in the preparation of collagen oligopeptides from bovine bone collagen, three enzymatic hydrolysis parameters, hydrolysis temperature, hydrolysis time and enzyme-substrate ratio (E/S), were optimized by single factor experiments, and the optimal hydrolysis conditions were determined to be reaction at 60 ℃ for 3 h with an E/S of 400 U/g. Under these conditions, the hydrolysis efficiency of bovine bone collagen by Aa2_1884 reached 95.3%. The resultant hydrolysate contained 97.8% peptides, in which peptides with a molecular weight lower than 1000 Da and 500 Da accounted for 55.1% and 39.5%, respectively, indicating that the hydrolysate was rich in oligopeptides. These results indicate that Aa2_1884 likely has a promising potential application in the preparation of collagen oligopeptide-rich hydrolysate from bovine bone collagen, which may provide a feasible way for the high-value utilization of bovine bone collagen.     

Antiplatelet and Antithrombotic Effects of Isaridin E Isolated from the Marine-Derived Fungus via Downregulating the PI3K/Akt Signaling Pathway

Isaridin E, a cyclodepsipeptide isolated from the marine-derived fungus Amphichorda felina (syn. Beauveria felina) SYSU-MS7908, has been demonstrated to possess anti-inflammatory and insecticidal activities. Here, we first found that isaridin E concentration-dependently inhibited ADP-induced platelet aggregation, activation, and secretion in vitro, but did not affect collagen- or thrombin-induced platelet aggregation. Furthermore, isaridin E dose-dependently reduced thrombosis formation in an FeCl₃-induced mouse carotid model without increasing the bleeding time. Mechanistically, isaridin E significantly decreased the ADP-mediated phosphorylation of PI3K and Akt. In conclusion, these results suggest that isaridin E exerts potent antithrombotic effects in vivo without increasing the risk of bleeding, which may be due to its important role in inhibiting ADP-induced platelet activation, secretion and aggregation via the PI3K/Akt pathways.     

软枣猕猴桃新品系—‘蜜玉’的选育

‘蜜玉’是从混合实生后代中筛选出的优良资源,经无性繁殖系统选育出的软枣猕猴桃新品系。果实椭圆形,果皮绿色,光滑无毛,平均单果重12.1 g。果肉绿色,可溶性固形22.5 %,总糖13.4 %,总酸1.06 %,维生素C1050.0 mg?kg-1。口感较甜,香气浓郁,抗寒、抗病能力较强。在吉林左家地区,6月中旬开花,9月初成熟。果实在常温条件下第7天开始软熟,低温（2～4℃）条件下第24天开始软熟。     

极小种群植物“川柿”生物学特性及种子萌发方法研究

摘 要：【目的】为了保护和发展极小种群植物川柿,开展此研究。【方法】采用观测法,连续3年对其生物学特性研究;种子萌发方法：（1）后熟0、30、45、60天,剥离清洗播种;（2）后熟60天,以GA300、600、1000 mg/L溶液浸种1h;播种基质为河沙（保持一定湿度）,放置室内,统计萌发时间和出苗率。【结果】（1）川柿花期4-5月,10月为果熟期,单果直径32.7±5.80mm,单果重23.0±5.30g;种子肾形、千粒重1070g;成年植株呈隔年开花、结果现象;（2）种子经“后熟+河沙播种”,可萌发,其中以后熟60天的出苗率较高,为65%;直接播种种子,出苗率5%;“后熟+GA溶液浸种+河沙播种”,出苗率均高于65%,其中以GA600mg/L浸泡1h处理,出苗率最高为83.3%。【结论】极小种群植物川柿为常绿叶乔木,有隔年开花、结果现象; “果后熟60天+GA600mg/L浸泡种子1h +室内河沙播种”可提高种子萌发率,为川柿种子繁殖提供参考。