Effect of Euphorbia esula on Sheep Rumen Microbial Activity and Mass In Vitro

Most large herbivores avoid the invasive weed leafy spurge (Euphorbia esula L.), possibly because the plant contains secondary compounds including terpenoids and condensed tannins. On the other hand, E. esula has high nutritive value based on traditional measures such as crude protein, fiber, and dry matter disappearance and is consumed by sheep and goats. Our objective was to determine if material from undefoliated and previously defoliated E. esula shoots, mixed in different proportions with grass hay, adversely affects sheep rumen microbial activity and mass in vitro. Material from undefoliated and previously defoliated E. esula shoots was collected in June, July, and August 1994 near Grass Range, Montana. Usually, increasing levels of E. esula leaves and flowers in the mixtures increased in vitro dry matter and neutral detergent fiber disappearances (DMD, NDFD), microbial gas production, and microbial purine concentrations. In contrast, increasing levels of E. esula stems in the mixtures decreased DMD, NDFD, microbial gas production, and microbial purine concentrations. Rumen microbial gas production and purine concentrations were higher with leaves from previously defoliated than undefoliated shoots. In contrast, rumen microbial gas production and DMD were lowest for stems from previously defoliated shoots; these responses correlated with high concentrations of condensed tannins in stems of previously defoliated plants. In early summer, the high nutritive value of E. esula appears to offset any potential negative effects associated with secondary compounds. In late summer, microbial response appears more sensitive to the presence of secondary compounds, when nutritive value of this plant is declining.     

Evaluating the In Vitro Metabolism of Docosahexaenoic Acid in Sheep Rumen Fluid

Rumen metabolism (e.g., biohydrogenation) of dietary unsaturated fatty acids (FA) is one of the main reasons why ruminant fats tend to be highly saturated and contain many isomerized FA intermediates. The process by which long-chain (20- to 24-carbon FA) polyunsaturated FA (LC-PUFA) are metabolized by rumen bacteria is not as well understood as that of linoleic or linolenic acids. In order to better understand the fate of LC-PUFA in the rumen several concentrations of docosahexaenoic acid (DHA) were evaluated in in vitro batch incubations ranging from 100 to 1,500 μg per 6 mL of incubation volume using rumen fluid from sheep and incubated for 0, 1, 2, 3, and 6 h. From the results, it was shown that DHA was extensively metabolized at low (100 to 300 μg/6 mL incubation volume), but not at high level of inclusion (800 μg). At 300 μg of DHA most of the depleted DHA was recovered as LC-DHA metabolites within the first 6 h of incubation, and at the lowest levels (100 μg of incubation volume) further metabolism is apparent at 6 h. Using SP-2560 GC columns several LC-DHA metabolites were shown to elute after 24:0 and just past DHA, a region generally free of interfering FA. The present in vitro study would appear to be a useful method to evaluate the production of DHA metabolites in combination with its depletion.     

枯草芽孢杆菌对黑土中可培养微生物的生态效应

研究了微生物农药枯草芽孢杆菌对东北黑土中可培养微生物的生态影响.其动态变化表明:低质量分数枯草芽孢杆菌对细菌总数没有明显影响,较高质量分数枯草芽孢杆菌町促进细菌总数的显著增加,其中质量分数在3200 mg/kg时,枯草芽孢杆菌对细菌的刺激强度最高,为对照的11倍.枯草芽孢杆菌对土壤中的放线菌也有刺激作用,刺激强度最高时,放线菌数量可增至对照的8.3倍左右.枯草芽孢杆菌对真菌的敏感性较低,只有质量分数高达3200 mg/kg时,才对真菌产生明显刺激作用,最高刺激强度为同时期对照的29倍.     

枯草芽孢杆菌对土壤呼吸作用和脲酶活性的影响

通过模拟实验研究了微生物农药枯草芽孢杆菌对黑土的呼吸作用和脲酶活性的生态毒理效应.结果表明:枯草芽孢杆菌各质量分数处理均表现为对土壤呼吸作用的刺激效应,并且土壤巾枯草芽孢杆菌质量分数越大,对土壤呼吸强度的刺激作用越大,其中最高质量分数(3200 mg/kg干土)处理在第42天时达到最大刺激强度,刺激率为69.1%.与对照相比,除第1天外,所有处理(32～3200 mg/kg干土)对土壤脲酶均表现出刺激效应,其中最高质量分数(3200 mg/kg干土)处理在第28天脲酶活性上升到最高,刺激率达到101.1%.     

丹参酮体外抗氧化活性研究

用Schaal烘箱法、邻苯三酚法、水杨酸法测定丹参酮对油脂抗氧化能力、清除超氧阴离子(O2-.)及清除羟自由基(.OH)能力。结果表明丹参酮对三种食用油脂均有良好的抗氧化效果,且抗氧化作用具有剂量效应关系;VC、柠檬酸及酒石酸对丹参酮的抗氧化作用均有协同增效作用;丹参酮对超氧阴离子(O2-.)和羟自由基(.OH)有良好的清除作用,且清除作用具有剂量效应关系。丹参酮具有良好的抗氧化活性,可将其作为一种天然的抗氧化剂用于抗衰老、抗肿瘤等药物研究中,进一步开发其药用价值。     

不同肟类N－甲基氨基甲酸酯的杀虫活性和离体胆碱酯酶抑制作用的研究

文中测定了一系列α－氰基甲酮肟和三氟甲基苯基甲酮肟类Ｎ－甲基氨基甲酸酯的杀虫活性和抑制胆碱酯酶活性。α－氰基烷基甲酮肟类Ｎ－甲基氨基甲酸酯具有极好的杀虫活性和抑制胆碱酯酶活性，而α－氰基苯基甲酮肟类衍生物仅仅呈现抑制胆碱酯酶活性。三氟甲基苯基甲酮肟类Ｎ－甲基氨基甲酸酯具有有力的杀虫活性和胆碱酯酶抑制活性。     

羧甲基槲皮素的体外抑菌活性研究

考察了槲皮素的水溶性衍生物3′-羧甲基槲皮素钠及4′-羧甲基槲皮素钠的体外抑菌活性。方法:用培养基将3′-羧甲基槲皮素钠及4′-羧甲基槲皮素钠进行倍比稀释,加入菌液至终浓度为107 cfu.mL-1,通过比浊法测定加药后细菌的生长情况。结果是3′-羧甲基槲皮素钠对金黄色葡萄球菌Staphylococcus aureus、金黄色葡萄球菌Wright、肺炎克雷伯菌、大肠杆菌、中间普氏菌的最小抑菌浓度分别为0.05,0.1,0.8 mg.mL-1,1.6,0.05 mg.mL-1;最小抑菌浓度下的抑菌率分别为98.8%,87.3%,83.9%,100.0%,100.0%。4′-羧甲基槲皮素钠对金黄色葡萄球菌、带荚膜的金黄色葡萄球菌、肺炎克雷伯菌、大肠杆菌、中间普氏菌的最小抑菌浓度分别为0.05,0.1,0.8,1.6,0.05 mg.mL-1;最小抑菌浓度下的抑菌率分别为92.4%,78.6%,87.5%,97.9%,99.8%。结论:3′-羧甲基槲皮素钠及4′-羧甲基槲皮素钠对革兰阳性菌、革兰阴性菌及厌氧菌均有良好的抑菌作用。     

Coevolution of Rumen Epithelial circRNAs with Their Microbiota and Metabolites in Response to Cold-Season Nutritional Stress in Tibetan Sheep

This study explores the effects of the coevolution of the host genome (the first genome) and gut microbiome (the second genome) on nutrition stress in Tibetan sheep during the cold season. The rumen epithelial tissue of six Tibetan sheep (Oula-type) was collected as experimental samples during the cold and warm seasons and the study lasted for half a year. The cDNA library was constructed and subjected to high-throughput sequencing. The circRNAs with significant differential expression were identified through bioinformatics analysis and functional prediction, and verified by real-time quantitative PCR (qRT-PCR). The results showed that a total of 56 differentially expressed (DE) circRNAs of rumen epithelial tissue were identified using RNA-seq technology, among which 29 were significantly upregulated in the cold season. The circRNA-miRNA regulatory network showed that DE circRNAs promoted the adaptation of Tibetan sheep in the cold season by targeting miR-150 and oar-miR-370-3p. The results of correlation analysis among circRNAs, microbiota, and metabolites showed that the circRNA {"type":"entrez-nucleotide","attrs":{"text":"NC_040275.1","term_id":"1562187472","term_text":"NC_040275.1"}}NC_040275.1:28680890|28683112 had a very significant positive correlation with acetate, propionate, butyrate, and total volatile fatty acid (VFA) (p < 0.01), and had a significant positive correlation with Ruminococcus-1 (p < 0.05). In addition, circRNA {"type":"entrez-nucleotide","attrs":{"text":"NC_040256.1","term_id":"1562187491","term_text":"NC_040256.1"}}NC_040256.1:78451819|78454934 and metabolites were enriched in the same KEGG pathway biosynthesis of amino acids (ko01230). In conclusion, the host genome and rumen microbiome of Tibetan sheep co-encoded a certain glycoside hydrolase (β-glucosidase) and coevolved efficient VFA transport functions and amino acid anabolic processes; thus, helping Tibetan sheep adapt to nutrient stress in the cold season in high-altitude areas.     

倍半萜类化合物的抑菌活性测定

二氢沉香呋喃倍半萜具有杀虫、抗炎、抗肿瘤等多种生物活性。我们由山道年出发,开拓了一条全新的、简洁的合成二氢沉香呋喃倍半萜骨架的方法,获得了一系列新化合物。采用菌丝生长速率测定法,初步研究表明,桉烷类倍半萜化合物对瓜果腐霉菌、辣椒疫霉菌、茄子立枯病菌、瓜类枯萎病菌、番茄灰霉病菌等植物病原真菌均有一定的生物活性。SH106和SH107号化合物在200mg／L时对瓜果腐霉菌的抑制活性高于90％,如果进一步进行结构改造,有望开发成为一类新型仿生合成的杀菌剂。     

丙烷脒类似物抑菌活性研究

以番茄灰霉病菌和白菜黑斑病菌等植物病原菌作为供试生物,用抑制菌丝生长速率法测定了合成的10个丙烷脒类似物的抑菌活性。结果表明：在供试浓度为10mg／L时,化合物A1-A5对番茄灰霉病菌、白菜黑斑病菌、苹果干腐病菌和烟草赤星病菌菌丝生长抑制率均在80％以上;化合物B5对小麦纹枯病菌菌丝生长抑制率为82．2％,值得进一步研究。     

重金属对活性污泥微生物活性的影响

本研究采用简单活性污泥法,使用对重金属中毒较为敏感的脱氢酶活性和更贴近活性污泥实际情况的耗氧速率作为活性污泥微生物中毒的评价指标,研究了铅、汞、铜、锌、铬(Ⅲ)五种重金属对活性污泥中微生物活性的影响。研究结果表明,五种重金属对活性污泥中微生物活性均有抑制作用,当重金属浓度达到45 mg/L时,五种重金属对活性污泥有机物降解能力的抑制率分别达到45.52%,50.44%,61.51%,27.94%,26.19%;对活性污泥脱氢酶活性抑制率分别达到62.49%,82.43%,79.17%,60.41%,62.39%。五种重金属对活性污泥的毒性大小为:铜汞铅铬锌。     

油橄榄酒体外抗氧化作用研究

利用Fenton反应、连苯三酚自氧化产生羟自由基（·OH）和超氧阴离子自由基（·Of），采用分光光度法研究了油橄榄酒活性物对自由基的清除作用，实验结果表明，橄榄酒能较好清除·OH、·02-自由基，清除效果接近于Vc。     

腐植酸肥对土壤养分与微生物活性的影响

本试验进行了腐植酸肥对土壤微生物活性与土壤速效养分影响的研究。试验在温室条件下,采用盆栽饲草高粱法,设腐植酸肥、化肥和对照（CK）3个处理。试验表明：抽穗期,腐植酸肥处理的土壤细菌数比化肥处理高4558％;拔节期和抽穗期,腐植酸肥处理的土壤放线菌数比化肥处理高2857％和4358％,土壤真菌数比化肥处理高弱26％－20...     

双脱氢枞基酰胺化合物的合成与体外抑菌活性

以脱氢枞酸为原料,在二氯甲烷溶剂中与二氯亚砜制备脱氢枞酰氯,再以无水碳酸钠作缚酸剂,脱氢枞酰氯与脱氢枞胺在四氢呋喃溶剂中回流生成双脱氢枞基酰胺化合物,收率46.3％.产物结构经核磁共振氢谱、碳谱及红外光谱确证.采用琼脂二倍稀释法对产物进行金黄色葡萄球菌、粪肠球菌、肺炎链球菌、铜绿假单胞菌、大肠埃希菌和阴沟肠杆菌6个菌种的体外抑菌活性实验,结果表明双脱氢枞基酰胺化合物对6个菌种的体外最低抑菌浓度(MIC)为8～128μg/mL,其中,对肺炎链球菌、阴沟肠杆菌的最低抑菌浓度(MIC)均为8μg/mL.     

单宁酸磷酸酯的合成及其抗氧化性能评价

以单宁酸为原料、三聚磷酸钠为磷酰化试剂、尿素为催化剂进行磷酸化反应合成单宁酸磷酸酯。通过正交实验优化最佳合成工艺,并利用磷含量计算产率,通过傅里叶红外光谱(FT-IR)、紫外光谱(UV)表征其结构。研究了单宁酸磷酸酯的电导性,并利用其对羟基自由基(·OH)和超氧阴离子自由基(·O_2~-)的清除能力评价了抗氧化性能。结果表明,最佳合成工艺条件为n(单宁酸)∶n(三聚磷酸钠)=1∶1、反应时间为18 h、反应温度为65℃,在此条件下的产率可达86.02%。产物的电导率与其质量浓度呈显著正相关,并在一定浓度下电导率比相应单宁酸高出10~15倍;当质量浓度为1 g/L时,产物与单宁酸对·OH和·O_2~-清除率分别为75%和55%。结果证明,在优化的最佳条件下产率较高,所合成的单宁酸磷酸酯具有较好的抗氧化活性。     

竹荪多糖的提取工艺及其体外抗氧化性研究进展

竹荪多糖是竹荪发挥保健作用的主要物质,对于多种人体疾病的预防和治疗有重要意义.综述了竹荪多糖的主要提取方法及其体外抗氧化性研究进展,为工业生产在提高竹荪多糖产率与降低成本等方面提供理论依据.     

血管活性肠肽的固相合成及其体外抗菌活性研究

采用Na-芴甲氧羰基（FMOC）作为α-氨基的保护基,以逐个延伸的固相合成法合成了血管活性肠肽,以最小抑菌浓度（MIC）评价其体外抗菌活性。高效液相色谱和质谱分析表明,所合成的血管活性肠肽的纯度为95.2%,相对分子质量为3326.5。血管活性肠肽对几种革兰氏阳性菌和革兰氏阴性菌有不同程度的抑制活性,其中对E.coli和P.aeruginosa的抑制效果最好。     

植物样品成分的体外抗氧化活性方法研究进展

综述了植物样品中成分的体外抗氧化活性评价方法,采用一种方法来评价具有多种功能多种类型的植物样品的抗氧化活性是不全面的,文中重点介绍了DPPH法、ABTs法、羟自由基（.OH）清除法、清除超氧阴离子自由基法和FRAP法等方法及采用这些方法取得的研究成果,以期为更好评价样品抗氧化活性提供理论依据。