不同干扰类型下滇西北高寒草甸土壤化学计量特征

为了解不同干扰类型对土壤养分的影响,本研究以云南迪庆州高寒草甸为对象,分析了封育?+?火烧、封育?+施肥、封育和放牧4种不同干扰类型下的土壤碳(C)、氮(N)、磷(P)、钾(K)化学计量特征.结果表明:1)在同一类型干扰下,土壤C、N、P、K浓度随着土层深度的增加而降低.土壤C、N、P、K浓度与土层深度表现为负相关关系...     

LPS-TLR4/MD-2–TNF-α signaling mediates alcohol-induced liver fibrosis in rats

Liver fibrosis results from liver inflammation and progresses to liver cirrhosis or liver cancer. It is known that nonalcoholic liver disease is mediated by the Toll-like receptor 4 (TLR4)/myeloid differentiation factor-2 (MD-2)–tumor necrosis factor-alpha (TNF-α) signaling pathway. This study aimed to investigate whether alcoholic liver disease is also mediated by this pathway. To this end, we first established rat models of liver fibrosis by administering alcohol. Next, the rats were injected with anti-TLR4 and anti-MD-2 antibodies. Real Time Quantitative PCR (RT-qPCR) and Western blotting were used to detect the activation of the TLR4/MD-2–TNF-α signaling pathway and hepatic stellate cells (HSCs). Moreover, the expression of molecules related to liver fibrosis was estimated. The morphology of rat liver tissue was observed through hematoxylin–eosin staining and Masson staining. For in vitro studies, Kupffer cells (KCs) isolated from the liver were transfected with si-TLR4 and si-MD-2 and co-cultured with HSCs to determine the activity of HSCs. It was found that alcohol treatment activated the TLR4/MD-2–TNF-α signaling pathway and upregulated the molecules associated with liver fibrosis. However, inhibition of TLR4 and MD-2 partially reversed this trend. Notably, in vitro studies indicated that knockdown of TLR4 and MD-2 in KCs partially inhibited LPS-induced activation of KCs and HSCs. Overall, this study showed that alcohol induces liver fibrosis via the LPS-TLR4/MD-2–TNF-α signaling pathway.     

官方兽医涉嫌犯动植物检疫徇私舞弊罪的解析

官方兽医是维护兽医卫生正常秩序的"保卫者",关系到动物疫病防控效果、养殖业健康发展和公共卫生安全。但近期频繁出现官方兽医的违法案例,其中涉嫌犯动植物检疫徇私舞弊罪的案例占了很大比例。本文通过对动植物检疫徇私舞弊罪的概念和构成要件进行分析,解析了官方兽医涉嫌犯动植物检疫徇私舞弊罪的若干方面内容。     

色质联用（GC／MS）研究天祝微孔草草籽油中的脂肪酸

采用色谱－质谱二联仪研究天祝微孔草草籽油的化学成分。共分离鉴定出１１种化合物，占油样总量的９９．９２％，主要是亚油酸，油酸，α－亚麻酸，顺－１１－二十碳烯酸，软脂酸，γ－亚麻酸，硬脂酸。饱和脂肪酸４种，不饱和脂肪酸７种，含量分别占总量的１３．５４％和８６．４６％。γ－亚麻酸含量为６．３７％，种子含油４３．５％。     

Sulfadiazine pharmacokinetics in grass carp (Ctenopharyngodon idellus) receiving oral and intravenous administrations

This study aimed to examine the bioavailability (BA) and pharmacokinetic (PK) characteristics of sulfadiazine (SDZ) in grass carp (Ctenopharyngodon idellus) after oral and intravenous administrations. Blood samples were collected at predetermined time points of 0.083, 0.17, 0.5, 1, 2, 4, 8, 16, 24, 48, 72, and 96 hr (n = 6). The samples were extracted and purified by organic reagents and determined by the ultra‐performance liquid chromatography. The software named 3P97 was used to calculate relevant PK parameters. The results demonstrated that the concentration–time profile of SDZ was best described by a one‐compartmental open model with first‐order absorption after a single oral dose. The main PK parameters of the absorption rate constant (K_α), the absorption half‐life (t_{1/2 Kα}), the elimination rate constant (K_e), the elimination half‐life (t_1/2Ke), and the area under concentration–time profile (AUC_0‐∞) were 0.3 1/h, 2.29 hr, 0.039 1/h, 17.64 hr, and 855.78 mg.h/L, respectively. Following intravenous administration, the concentration–time curve fitted to a two‐compartmental open model without absorption. The primary PK parameters of the distribution rate constant (α), the elimination rate constant (β), the distribution half‐life (t_1/2α), the elimination half‐life (t_1/2β), the apparent distribution volume (V_SS), the total clearance (CL), and AUC_0‐∞ were 9.62 1/hr, 0.039 1/hr, 0.072 hr, 17.71 hr, 0.33 L/kg, 0.013 L h^?1 kg^?1, and 386.23 mg.h/L, respectively. Finally, the BA was calculated to be 22.16%. Overall, this study will provide some fundamental information on PK properties in the development of a new formulation SDZ in the future and is partially beneficial for the appropriate usage of SDZ in aquaculture.     

水稻瘤矮病—广东湛江新发生的一种水稻病毒病

 广东新发生的水稻瘤矮病于1981~1982年在广东湛江地区的信宜、高州和化州县发生流行。室内用叶蝉接种2叶龄的稻苗,在10~11月广州温室温度约为土9~23℃下,潜育期为13~28天,主要症状为病苗矮缩,叶片浓绿色,叶背及叶鞘上长有若干个淡黄绿色近圆形小瘤(0.1~1.2毫米直径)。病毒粒子球状,直径约60毫微米。昆虫介体为电光叶蝉(Recilia dorsalis Motsch.)和黑尾叶蝉(Nephotettix cinticeps Uhler.)。褐稻虱(Nilaparvata lugens Stal.)和白背飞虱(Sagatella furcifera Horvath.)不能传病。二点黑尾叶蝉(N.virescence Distant.)和大斑黑尾叶蝉(N.apicalis Motsch)还有待进一步研究决定。电光叶蝉的最短获毒饲育期少于24小时。潜育期在平均室温22~23℃下为13~24天。保毒虫能终生传毒。根据上述实验结果,初步认为本病与泰国和马来西亚报道的水稻瘤矮病相同。     

彪虎防除小麦田杂草的效果

兴化市地处江苏里下河中心地区,麦田草害较重。受爱利思达生物化学品有限公司委托,对该公司生产的70%彪虎WG防除小麦田杂草的效果进行了试验。1材料与方法1.1供试药剂供试药剂有:70%彪虎WG、彪虎专用助剂、彪虎新专用助剂(以上均为爱利思达生物化学品有限公司提供)、885助剂(无锡友联精细化工有限公司产品)、6.9%骠马EW(拜耳作物科学公司产品)、6.9%新骠EW(江阴青阳农药有限公司产品)、10%苯磺隆WP(扬农化工集团产品)、20%使它隆EC(美国陶氏益农公司产品)。1.2试验方法试验分冬季与春季两次进行,冬季设8个处理:70%彪虎WG 2 g/667m2、7…     

A molecular mechanism of resistance to streptomycin in <Emphasis Type="Italic">Xanthomonas oryzae</Emphasis> pv. <Emphasis Type="Italic">oryzicola</Emphasis>

Xanthomonas oryzae pv. oryzicola, the causal agent of rice leaf streak disease, was found to be sensitive to streptomycin (an aminocyclitol glycoside antibiotic), by inhibition of protein synthesis resulting from interference with translational proofreading. This study aimed to determine the molecular resistance mechanism of X. oryzae pv. oryzicola to streptomycin. Seven streptomycin-resistant mutants were obtained by UV induction or streptomycin selection. These mutants can grow at 100 μg ml⁻¹ of streptomycin while the wild-type strain (RS105) cannot grow at 5 μg ml⁻¹. Sequencing indicated that the rpsL gene encoding ribosomal protein S12 has 375 bp encoding 125 amino acid residues. In all resistant strains, a mutation in which AAG was substituted for AGG (Lys→Arg) occurred either at codon 43 or 88. Two plasmids, pUFRRS and pUFRRX, were constructed by ligating the rpsL gene into the cosmid pUFR034. The plasmids pUFRRS and pUFRRX containing the Lys→Arg mutation of the rpsL gene conferred streptomycin resistance to the sensitive wild-type strain by electroporation. Both transformants, RS1 and RS2, could grow in the medium containing 50 μg ml⁻¹ of streptomycin. A mutation at codon 43 or 88 in rpsL can result in resistance of Xanthomonas oryzae pv. oryzicola to streptomycin.     

氯虫苯甲酰胺和氟虫双酰胺对不同虫态甜菜夜蛾的毒力作用

采用浸叶法、点滴法、夹毒叶片法、成虫药膜法、饲喂毒营养液法测定了氯虫苯甲酰胺、氟虫双酰胺对甜菜夜蛾卵、2~4龄幼虫、成虫的活性和对4龄幼虫的拒食活性,以明确氯虫苯甲酰胺和氟虫双酰胺对不同虫态甜菜夜蛾的毒力作用。结果表明,两种杀虫剂均不具有杀卵活性,但可以明显降低初孵幼虫存活率;氯虫苯甲酰胺、氟虫双酰胺均对2龄幼虫活性最高,分别为3龄幼虫的1.50、6.17倍和4龄幼虫的22.25、44.95倍,对4龄幼虫胃毒活性分别为触杀活性的14.10、8.44倍;氯虫苯甲酰胺对甜菜夜蛾成虫毒力为氟虫双酰胺的25.53~34.19倍。氯虫苯甲酰胺、氟虫双酰胺对甜菜夜蛾幼虫表现出较强的拒食作用, 至处理后48 h拒食率达到最高, 分别为 82.73%、84.15%,显著高于对照药剂甲维盐各浓度处理,处理试虫虫体皱缩、体节缩短,体重增加率明显低于对照和甲维盐各处理。     

Diet composition, herbage intake and digestibility in Inner Mongolian Cashmere goats grazing on native Leymus chinensis plant communities

The botanical composition, intake and digestibility of the diet selected by Inner Mongolian Cashmere goats grazing on a native Leymus chinensis plant community were measured in two grazing periods (June and August) using the n-alkane markers. In each grazing period, 48 Inner Mongolian Cashmere goats (24 wethers and 24 does with an average live weight of 22.1 ± 1.2 kg and 19.6 ± 0.8 kg, respectively) were divided in two groups (G1: grazing group; G2: cage-fed group) of 24 animals each. Based on the observation of G1 grazing behaviour, G2 goats were fed on herbage obtained by a simulative method and were housed in metabolism cages to determine the alkane faecal recoveries. Diet composition was estimated by comparing the odd-chain n-alkane pattern (C₂₅–C₃₅) of the selected plant species with the n-alkane faecal concentrations, corrected for their incomplete faecal recovery. The alkane pair C₃₂:C₃₃ and C₃₆ alkane were used to estimate intake and diet digestibility, respectively. The results showed that the increase of herbage availability from June to August, resulted in higher (P < 0.05) DM, CP, ME, ADF and NDF intake of both wethers and does, with no evident changes in ADF and NDF intake in does., The intake of nutrients differed significantly between wethers and does in both experimental periods, except for NDF in EP1 and ME in EP2. Differences between grazing seasons and goats' sex in nutrients digestibility were not observed. Diet composition indicated seasonal differences, being Sonchus brachyotus, Artemisia frigida and Phragmites communis the main components of the diet in June. However, Suaeda corniculata, Chloris virgata, Xanthium sibiricum and Echinochloa crusgalli became the main diet components in August. Moreover, the sex affected significantly the diet choices in both grazing periods.