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Q494; 野生动物应激水平的非损伤性评估是了解野生动物对景观条件产生生理反应的重要方法.粪便皮质醇代谢产物(faecal cortisol metabolites,FCM)水平被认为是评价动物压力的潜在生物标志物.影响濒危东北马鹿(Cervus elaphus xanthopygus)应激的环境因子可能包括道路、植被、人为干扰和海拔等,因此采用酶联免疫分析法(ELISA)分析内蒙古高格斯台罕乌拉国家级自然保护区东北马鹿种群的粪便皮质醇激素数据,利用多元线性回归模型构建东北马鹿粪便皮质醇激素与环境因子的线性关系,探索环境因子影响东北马鹿粪便皮质醇激素的变化情况.结果表明:82只不同东北马鹿个体粪便皮质醇激素水平为 2.05～114.3 ng/g,平均水平为(37.56±24.25)ng/g.距道路距离、归一化植被指数(normalized difference vegetation index,NDVI)和海拔是驱动皮质醇激素水平变化的主要因子.马鹿粪便皮质醇激素水平与距道路距离、NDVI呈负相关,与海拔呈正相关.随着海拔的升高,马鹿平均粪便皮质醇水平呈上升趋势.测量粪便皮质醇激素为评估环境压力下应激源对野生动物的影响提供了一种无损伤性监测策略.了解环境因子对东北马鹿粪便皮质醇的影响,可以为制定保护区管理政策和保护策略提供理论基础.

目的探讨人骨髓间充质干细胞（hBMSCs）定向血管内皮细胞诱导分化前后内皮型一氧化氮合酶（eNOS）基因表达、活性及其代谢产物的差异。方法建立hBMSCs定向血管内皮细胞诱导分化系统。应用倒置显微镜观察细胞形态的改变,Transwell实验检测细胞的迁移能力,细胞免疫荧光及Western blot检测eNOS的蛋白表达,ELISA法检测eNOS的活性,硝酸还原法检测细胞培养上清液NO含量。结果与未分化组相比,分化后的细胞形态发生明显改变;细胞的迁移能力增强238.10%（73.000±7.002 vs.21.000±4.359,P〈0.05）;eNOS蛋白的表达增加114.72%（0.423±0.011 vs.0.197±0.079,P〈0.05）;eNOS的活性增强157.49%（4.967±0.073 vs.1.929±0.103,P〈0.05）;NO合成与释放增加155.67%（184.909±1.853 vs.72.323±0.426,P〈0.05）。结论 hBMSCs定向内皮细胞诱导分化后eNOS基因表达增加、活性增强,其代谢产物NO的合成与释放增加。本结果可能为干细胞在心血管疾病等防治提供依据。

背景与目的国外研究表明不论以何种方式用烟草特有亚硝胺4-（甲基亚硝胺）-1-（3-吡啶）-1-丁酮[4-（methylnitrosamino）-1-（3-pyridyl）-1-butanone，NNK]处理小鼠均能特异地诱发小鼠肺癌，且多为肺腺癌，NNK是公认的吸烟者患肺癌的一个病因。本研究的目的是通过测定吸烟者尿中NNK的代谢产物4-（甲基亚硝胺）-1-（3-吡啶）-1-丁醇[4-（methylnitrosamino）-1-（3-pyridyl）-1-butanol，NNAL]及其解毒产物4-（甲基亚硝胺）-1-（3-吡啶-N-氧化物）-1-丁醇E4-（methylnitrosamino）-1-（3-pyridyl—N—oxide）一1一butanol，NNAL-Gluc]的含量及NNAL，Gluc／NNAL比值来了解NNK特异的致肺癌性。方法 用高压液相色谱仪（HPLC）和气相色谱-双极质谱联用仪（GC—Ms／MS）对10例吸烟肺癌患者、8例健康吸烟者和4例健康不吸烟者的24h尿样进行分析。结果 不吸烟者的尿中未测到NNAL和NNAL-Gluc，健康吸烟者尿中平均NNAL-Gluc／NNAL比值为4．95，吸烟肺癌患者为0．5。结论 建立了在吸烟者尿中测定NNK代谢产物NNAL及NNAL-Gluc的方法。初步研究显示健康吸烟者对NNK的解毒能力明显大于吸烟肺癌患者，为在吸烟人群中筛选肺癌高危人群提供了检测手段。

Urine samples were collected from seven farmers before and after applying 20% amitraz EC to pear and citrus fields. Amitraz and its metabolites including BTS-27919, BTS-27271, and 2,4-dimethylaniline were eluted with n-hexane, dichloromethane and methanol in sequence from SPE-C18 cartridge by loading 5 mL of urine before GC-MSD determination. The mean recoveries of amitraz, BTS- 27919, BTS-27271 and 2,4-dimethylaniline were 75.7 ± 4.2 , 81.3 ± 2.4 , 87.7 ± 3.7 and 83.3 ± 1.8%, respectively. Neither amitraz nor metabolites were detected in any of the seven farmers’ urine samples.

Dibenzoylmethane (DBM), a curcumin-related β-diketone analogue, has been reported to exhibit a remarkable inhibitory effect on 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary tumorigenesis in Sencar mice. Investigation of the underlying mechanisms of DBM in the prevention of mammary tumorigenesis implied its role as an effector of Phase I enzymatic system. In this report, the metabolic fate of DBM by NADPH-dependent cytochrome P450 enzymes in mouse liver microsomes was demonstrated. Isolation of the major reductive metabolites of DBM (DBMH2), together with several minor metabolites identified by NMR, GC and LC-MS, explained the potential role of DBM as a modulator of the cytochrome P450 reductase that is required for the function of oxidase to metabolize DMBA. These might also contribute to the result of the inhibitory effect of DBM on DMBA-induced mouse mammary tumorigenesis.

Methanogenic archaea reside primarily in the rumen and the lower segments of the intestines of ruminants, where they utilize the reducing equivalents derived from rumen fermentation to reduce carbon dioxide, formic acid, or methylamines to methane（CH_4）. Research on methanogens in the rumen has attracted great interest in the last decade because CH_4 emission from ruminants contributes to global greenhouse gas emission and represents a loss of feed energy. Some DNA-based phylogenetic studies have depicted a diverse and dynamic community of methanogens in the rumen. In the past decade, researchers have focused on elucidating the underpinning that determines and affects the diversity, composition, structure, and dynamics of methanogen community of the rumen. Concurrently, many researchers have attempted to develop and evaluate interventions to mitigate enteric CH_4 emission. Although much work has been done using plant secondary metabolites, other approaches such as using nitrate and 3-nitrooxy propanol have also yielded promising results. Most of these antimethanogenic compounds or substances often show inconsistent results among studies and also lead to adverse effects on feed intake and digestion and other aspects of rumen fermentation when fed at doses high enough to achieve effective mitigation. This review provides a brief overview of the rumen methanogens and then an appraisal of most of the antimethanogenic compounds and substances that have been evaluated both in vitro and in vivo. Knowledge gaps and future research needs are also discussed with a focus on methanogens and methane mitigation.

Intestinal bacterial metabolites are an important communication tool between the host immune sys tem and the commensal microbiota to establish mutualism. In a recent paper published in Science, Wendy Garrett and her colleagues report an exciting role of the three most abundant microbial-derived short chain fatty acids （SCFA）, acetic acid, propionic acid and butyric acid, in colonic regulatory T cell （cTreg） ho meostasis.

This study analyzed the effects of ecological factors on secondary metabolites of Scutellaria baicalensis using two sources： 92 individual roots of S. baicalensis from all over China, and secondary metabolites, medicinal materials and inorganic element contents obtained from the testing of 92 S. baicalensis rhizosphere soil samples. The study used environmental data from the Genuine Medicinal Material Spatial Analysis Database. Most of the chemical constituents of S. baicalensis were negatively correlated to latitude and positively correlated to temperature; generally, the contents of 21 chemical constituents were higher at low latitudes than that at high latitudes. By gradual regression analysis, it was found that the content of baicalin in S. bai- calensis was negatively correlated to latitude and generally the content of inorganic elements in soil was excessively high （ex- cluding Mg and Ca）, which has a negative effect on the accumulation of chemical constituents in S. baicalensis. Based on the cluster analysis of 21 constituents, S. baicalensis from different places of origin was divided into two groups, and S. bai- calensis was not genuine only in a specific small region. Within the zone from Chifeng, Inner Mongolia to Taibai, Shaanxi is suitable for accumulation of secondary metabolites of S. baicalensis and such a zone represents a suitable distribution and po- tential genuine producing area.

Although methylenetetrahydrofolate reductase, a folate enzyme gene, has been associated with idiopathic male infertility, few studies have examined other folate-related metabolites and genes. We investigated whether idiopathic male infertility is associated with variants in folate, vitamin B12 （B12） and total homocysteine （tHcy）-related genes and measured these metabolites in blood. We conducted a case-control study that included 153 men with idiopathic infertility and 184 fertile male controls recruited at the Fertility Center and Antenatal Care Center, University Hospital, Malmo and Lund, Sweden. Serum folate, red cell folate （RCF）, serum B12, plasma tHcy and semen quality were measured. Subjects were genotyped for 20 common variants in 12 genes related to folate/B12/ homocysteine metabolism. Metabolite concentrations and genotype distributions were compared between cases and controls using linear and logistic regression with adjustment for covariates. The phosphatidylethanolamine N-methyltransferase （PEMT） M 175V and TCblR rs173665 polymorphisms were significantly associated with infertility （P=0.01 and P=0.009, respectively）, but not with semen quality. Among non-users of supplements, infertile men had lower serum folate concentrations than fertile men （12.89 vs. 14.73 nmoll^- 1 P=0.02）, but there were no significant differences in RCF, B 12 or tHcy. Folate, B 12 and tHcy concentrations were not correlated with any semen parameters. This study provides little support for low folate or B12 status in the pathogenesis of idiopathic male infertility. Although additional data are needed to confirm these initial findings, our results suggest that PEMTand TCbIR, genes involved in choline and B12 metabolism, merit further investigation in idiopathic male infertility.

Antibiotics are most important compounds in microbial secondary metabolites.As we know,streptomycetes are a particularly abundant source of antibiotics and related compounds,providing more than half of medically important antimicrobial and antitumor agents.Various environmental and physiological conditions influence the onset and level of antibiotic production.Because of improper use and abuse of antibiotics as well as the horizontal transfer of antibiotic resistance genes between bacteria by conjugation,transduction or transformation, these have led to the appearance of antibiotic resistance and the loss of antibiotic native efficiency.