旅游干扰下水质对大鲵繁殖行为与繁殖力的影响

通过控制大鲵仿生态繁育池进水量模拟旅游干扰下的水质溶解氧特征,采用红外数字监控系统研究大鲵繁殖行为(产卵与护卵)及繁殖力(相对产卵量、受精率与孵化率)特点,分析它们与水质的关系,探讨旅游干扰导致的水质变化对大鲵繁殖行为及繁殖力的影响.结果 表明:与对照组相比,旅游干扰下大鲵的产卵行为与繁殖力未受到显著影响,但雄鲵护卵行...     

Lyciumamide A,a dimer of phenolic amide,protects against NMDA-induced neurotoxicity and potential mechanisms in vitro

Journal of Molecular Histology - Currently, the excessive activation of N-methyl-D-aspartate receptors (NMDARs) is considered to be a crucial mechanism of brain injury. Lycium barbarum A (LyA) is a...     

不同光照强度对兴安落叶松几种主要防御蛋白活力的影响

林木组成抗性对抵御害虫危害发挥着重要作用。为了研究环境因子对其组成抗虫性的影响,以兴安落叶松幼苗为试验材料,通过搭建遮阳棚设置3个光照强度(自然光照作为对照、50%和25%自然光照强度),模拟森林幼苗生长的林缘、林窗和林下3种不同的光环境,分析不同光照强度对其针叶内与植物抗虫性有关的几种主要防御蛋白活力的影响。研究结果表明,不同光照强度对针叶内主要防御蛋白活力有显著影响(P<0.05)。50%和25%光照强度下,POD、SOD、PAL、PPO和CI的活性显著高于自然光照下的(P<0.05),POD和CI的活性在50%光照强度下最高,SOD、PAL和PPO的活性在25%光照强度下最高;自然光照条件下CAT的活性显著高于50%和25%光照强度下的(P<0.05);遮荫处理对TI的活性有显著影响(P<0.05),但在不同月份中波动较大,规律性不明显。相同的光照强度条件下,主要防御蛋白活力在3个月中也有显著变化(P<0.05)。7月和8月份保护性酶POD和CAT的活性显著高于6月(P<0.05);防御性酶PAL、PPO以及蛋白酶抑制剂CI的活性在6月份最高。综合以上研究结果,光照可影响兴安落叶松针叶中几种主要防御蛋白活力,这也说明在较荫蔽的光照环境下,兴安落叶松有较强的抗性。其中SOD、CAT、PAL、PPO和POD是植物次生物质生成过程中的关键酶,其活性的改变在一定程度上表征着植物防御体系在变化。研究环境因子与植物防御之间的关系具有重要的理论和实际应用价值。     

植物种群自疏过程中构件生物量与密度的关系

不论是在对植物种群自疏规律还是在对能量守衡法则的研究中,个体大小(M)大多针对植物地上部分生物量,地下部分和构件生物量及其动态十分重要又多被忽视。以1年生植物荞麦为材料研究了自疏种群地下部分生物量、包括地下部分的个体总生物量以及各构件生物量与密度的关系。结果表明:平均地上生物量和个体总生物量与密度的异速关系指数(γabove-ground和γindividual)分别为-1.293和-1.253,与-4/3无显著性差异(P>0.05),为-4/3自疏法则提供了有力证据;平均根生物量-密度异速指数γroot(-1.128)与-1无显著性差异(P>0.05),与最终产量恒定法则一致;平均茎生物量-密度异速指数γstem(-1.263)接近-4/3(P>0.05),平均叶生物量-密度异速指数γleaf(-1.524)接近-3/2(P>0.05),分别符合-4/3自疏法则与-3/2自疏法则;而繁殖生物量与密度的异速关系指数γreproductive(-2.005)显著小于-3/2、-4/3或-1(P<0.001)。因此,不存在一个对植物不同构件普适的生物量-密度之间的关系。光合产物在地上和地下构件的生物量分配格局以及构件生物量与地上生物量之间特异的异速生长关系导致不同构件具有不同的自疏指数。无论对于地上生物量还是个体总生物量,荞麦种群能量均守衡,而对于地下生物量,荞麦种群能量不守衡。     

Changing dendritic field size of mouse retinal ganglion cells in early postnatal development

During early postnatal development, dendrites of retinal ganglion cells (RGCs) extend and branch in the inner plexiform layer to establish the adult level of stratification, pattern of branching, and coverage. Many studies have described the branching patterns, transient features, and regulatory factors of stratification of the RGCs. The rate of RGC dendritic field (DF) expansion relative to the growing retina has not been systematically investigated. In this study, we used two methods to examine the relative expansion of RGC DFs. First, we measured the size of RGC DFs and the diameters of the eyeballs at several postnatal stages. We compared the measurements with the RGC DF sizes calculated from difference of the eyeball sizes based on a linear expansion assumption. Second, we used the number of cholinergic amacrine cells (SACs) circumscribed by the DFs of RGCs at corresponding time points as an internal ruler to assess the size of DFs. We found most RGCs exhibit a phase of faster expansion relative to the retina between postnatal day 8 (P8) and P13, followed by a phase of retraction between P13 and adulthood. The morphological α cells showed the faster growing phase but not the retraction phase, whereas the morphological ON–OFF direction selective ganglion cells expanded in the same pace as the growing retina. These findings indicate different RGCs show different modes of growth, whereas most subtypes exhibit a fast expansion followed by a retraction phase to reach the adult size. © 2009 Wiley Periodicals, Inc. Develop Neurobiol 70: 397–407, 2010     

海洋真菌产抗菌物质培养基及其性质研究

目的:海洋真菌Fy-04产抗菌物质培养基及性质研究.方法:管碟法测定抑菌效果确定海洋真菌Fy-04产抗菌物质的培养基及其性质.结果:海洋真菌Fy-04产抗菌物质对金黄色葡萄球菌抑菌最佳培养基组成为:马铃薯海水浸出液60%,葡萄糖2%,蛋白胨1%,酵母膏0.1%,抑菌圈直径34.6mm;对大肠杆菌抑菌最佳培养基组成为:葡萄糖2%,蛋白胨0.7%,酵母膏0.1%,FePO4 0.04%,抑菌圈直径21.6mm;抗菌物质80℃处理1h,残留活性60%以上,pH稳定范围在pH 6.0～10.0.结论:该菌株代谢产物对细菌有较好的抑菌效果,并能溶于乙醚、三氯甲烷中等极性的有机溶剂中.     

随机SNP在全基因组关联研究人群分层分析中的应用

在复杂疾病的全基因组关联研究中,人群分层现象会增加结果的假阳性率,因此考虑人群遗传结构、控制人群分层是很有必要的。而在人群分层研究中,使用随机选择的SNP的效果还有待进一步探讨。文章利用HapMap Phase2人群中无关个体的Affymetrix SNP 6.0芯片分型数据,在全基因组上随机均匀选择不同数量的SNP,同时利用f值和Fisher精确检验方法筛选祖先信息标记（Ancestry Informative Markers,AIMs）。然后利用HapMap Phase3中的无关个体的数据,以F-statistics和STRUCTURE分析两种方法评估所选出的不同SNP组合对人群的区分效果。研究发现,随机均匀分布于全基因组的SNP可用于识别人群内部存在的遗传结构。文章进一步提示,在全基因组关联研究中,当没有针对特定人群的AIMs时,可在全基因组上随机选择3000以上均匀分布的SNP来控制人群分层。     

Patterning of diverse mammalian cell types in serum free medium with photoablation

Integration of living cells with novel microdevices requires the development of innovative technologies for manipulating cells. Chemical surface patterning has been proven as an effective method to control the attachment and growth of diverse cell populations. Patterning polyelectrolyte multilayers through the combination of layer‐by‐layer self‐assembly technique and photolithography offer a simple, versatile, and silicon compatible approach that overcomes chemical surface patterning limitations, such as short‐term stability and low‐protein adsorption resistance. In this study, direct photolithographic patterning of two types of multilayers, PAA (poly acrylic acid)/PAAm (poly acryl amide) and PAA/PAH (poly allyl amine hydrochloride), were developed to pattern mammalian neuronal, skeletal, and cardiac muscle cells. For all studied cell types, PAA/PAAm multilayers behaved as a cytophobic surface, completely preventing cell attachment. In contrast, PAA/PAH multilayers have shown a cell‐selective behavior, promoting the attachment and growth of neuronal cells (embryonic rat hippocampal and NG108‐15 cells) to a greater extent, while providing little attachment for neonatal rat cardiac and skeletal muscle cells (C2C12 cell line). PAA/PAAm multilayer cellular patterns have also shown a remarkable protein adsorption resistance. Protein adsorption protocols commonly used for surface treatment in cell culture did not compromise the cell attachment inhibiting feature of the PAA/PAAm multilayer patterns. The combination of polyelectrolyte multilayer patterns with different adsorbed proteins could expand the applicability of this technology to cell types that require specific proteins either on the surface or in the medium for attachment or differentiation, and could not be patterned using the traditional methods. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009     

The Composition of Microbiome in Larynx and the Throat Biodiversity between Laryngeal Squamous Cell Carcinoma Patients and Control Population

The throat is an ecological assemblage involved human cells and microbiota, and the colonizing bacteria are important factors in balancing this environment. However, this bacterial community profile has thus been poorly investigated. The purpose of this study was to investigate the microbial biology of the larynx and to analyze the throat biodiversity in laryngeal carcinoma patients compared to a control population in a case-control study. Barcoded pyrosequencing analysis of the 16S rRNA gene was used. We collected tissue samples from 29 patients with laryngeal carcinoma and 31 control patients with vocal cord polyps. The findings of high-quality sequence datasets revealed 218 genera from 13 phyla in the laryngeal mucosa. The predominant communities of phyla in the larynx were Firmicutes (54%), Fusobacteria (17%), Bacteroidetes (15%), Proteobacteria (11%), and Actinobacteria (3%). The leading genera were Streptococcus (36%), Fusobacterium (15%), Prevotella (12%), Neisseria (6%), and Gemella (4%). The throat bacterial compositions were highly different between laryngeal carcinoma subjects and control population (p = 0.006). The abundance of the 26 genera was significantly different between the laryngeal cancer and control groups by metastats analysis (p<0.05). Fifteen genera may be associated with laryngeal carcinoma by partial least squares discriminant analysis (p<0.001). In summary, this study revealed the microbiota profiles in laryngeal mucosa from tissue specimens. The compositions of bacteria community in throat were different between laryngeal cancer patients and controls, and probably were related with this carcinoma. The disruption of this bio-ecological niche might be a risk factor for laryngeal carcinoma.     

Identification and Effect Decomposition of Risk Factors for Brucella Contamination of Raw Whole Milk in China

Background

Lack of clear risk factor identification is the main reason for the persistence of brucellosis infection in the Chinese population, and there has been little assessment of the factors contributing to Brucella contamination of raw whole milk. The purpose of this study was to identify risk factors affecting Brucella contamination of raw milk, and to evaluate effective measures for disease reduction in order to determine preventive strategies.

Methods and Findings

A nationwide survey was conducted and samples were obtained from 5211 cows corresponding to 25 sampling locations throughout 15 provinces in China. The prevalence of Brucella in the raw milk samples averaged 1.07% over the 15 Chinese provinces, while the prevalence of positive areas within these regions ranged from 0.23–3.84% among the nine provinces with positive samples. The survey examined factors that supposedly influence Brucella contamination of raw whole milk, such as management style, herd size, abortion rate, hygiene and disease control practices. A binary logistic regression analysis was carried out to determine the association between risk factors for Brucella and contamination of milk samples. Furthermore, a relative effect decomposition study was conducted to determine effective strategies for reducing the risk of Brucella contamination of raw whole milk. Our data indicate that disease prevention and control measures, abortion rate, and animal polyculture are the most important risk factors. Meanwhile, culling after quarantine was identified as an effective protective measure in the current Chinese dairy situation.

Conclusions

These results indicate that, although there is a low risk of contamination of milk with Brucella nationwide in China, there are individual regions where contamination is a significant problem. Controlling three factors–culling after quarantine, maintaining a low abortion rate, and avoiding mixing groups of cattle and small ruminants–could effectively reduce the risk of Brucella contamination of raw whole milk.