The antibacterial lectin RegIIIgamma promotes the spatial segregation of microbiota and host in the intestine

The mammalian intestine is home to ~100 trillion bacteria that perform important metabolic functions for their hosts. The proximity of vast numbers of bacteria to host intestinal tissues raises the question of how symbiotic host-bacterial relationships are maintained without eliciting potentially harmful immune responses. Here, we show that RegIIIγ, a secreted antibacterial lectin, is essential for maintaining a ~50-micrometer zone that physically separates the microbiota from the small intestinal epithelial surface. Loss of host-bacterial segregation in RegIIIγ(-/-) mice was coupled to increased bacterial colonization of the intestinal epithelial surface and enhanced activation of intestinal adaptive immune responses by the microbiota. Together, our findings reveal that RegIIIγ is a fundamental immune mechanism that promotes host-bacterial mutualism by regulating the spatial relationships between microbiota and host.     

益生菌在肥胖及其代谢综合症中的潜在作用

肥胖以及相关的代谢综合症已经成为全球性的公共健康问题.大量的研究表明,肥胖形成以及减肥过程均与肠道茵群密切相关且相互影响.肠道茵群以及弱炎症反应成为肥胖以及相关代谢综合症的两大重要影响因素.文章综述了近几年来,肠道菌群失调对宿主能量储存以及新陈代谢的影响,以及弱炎症反应对肥胖引起的代谢综合症的影响.大量的研究证明,益生...     

PHYSIOLOGY OF THE AMINO ACIDS

We have followed the amino acids from their entrance into the alimentary tract in the form of food proteins through the successive steps of digestion, absorption into the blood stream and passage from the blood stream into the tissues, where they are concentrated by some unknown mechanism to many times their concentration in the blood plasma. We have seen something of the way in which certain of the amino acids can be transformed into one another in the body or synthesized from ammonia and keto acids. However, we have had to admit that our bodies can form in such ways only about half of the different amino acids that are required, and that the other half must be made for us by plants, bacteria or other organisms which have greater synthetic powers than we. And finally we have seen something of the manifold fates of the amino acids after they have entered our tissues; how they may be destroyed and their nitrogenous parts turned into urea in the liver before it is possible to put them to their more specialized uses, how their carbon fractions can be used to form glucose, how they may sacrifice themselves to protect us from toxic products, how they can serve as source material for certain vitamins, hormones and other compounds with physiological functions still to be identified, and how finally those amino acids which are not deflected to these various fates may enter into the proteins of the tissues and become for a time parts of our living structures.     

Is it time for a metagenomic basis of therapeutics?

The trillions of microbes associated with the human body are a key part of a comprehensive view of pharmacology. A mechanistic understanding of how the gut microbiota directly and indirectly affects drug metabolism is beginning to emerge.     

Diet drives convergence in gut microbiome functions across mammalian phylogeny and within humans

Coevolution of mammals and their gut microbiota has profoundly affected their radiation into myriad habitats. We used shotgun sequencing of microbial community DNA and targeted sequencing of bacterial 16S ribosomal RNA genes to gain an understanding of how microbial communities adapt to extremes of diet. We sampled fecal DNA from 33 mammalian species and 18 humans who kept detailed diet records, and we found that the adaptation of the microbiota to diet is similar across different mammalian lineages. Functional repertoires of microbiome genes, such as those encoding carbohydrate-active enzymes and proteases, can be predicted from bacterial species assemblages. These results illustrate the value of characterizing vertebrate gut microbiomes to understand host evolutionary histories at a supraorganismal level.     

A genomic view of the human-Bacteroides thetaiotaomicron symbiosis

The human gut is colonized with a vast community of indigenous microorganisms that help shape our biology. Here, we present the complete genome sequence of the Gram-negative anaerobe Bacteroides thetaiotaomicron, a dominant member of our normal distal intestinal microbiota. Its 4779-member proteome includes an elaborate apparatus for acquiring and hydrolyzing otherwise indigestible dietary polysaccharides and an associated environment-sensing system consisting of a large repertoire of extracytoplasmic function sigma factors and one- and two-component signal transduction systems. These and other expanded paralogous groups shed light on the molecular mechanisms underlying symbiotic host-bacterial relationships in our intestine.     

Genetics. L1 retrotransposons shape the mammalian genome

What are all of those retrotransposons doing buzzing about in our genome? According to Kazazian, in his Perspective this week, these mobile pieces of DNA are busy reshaping our genome, making it more diverse and enabling us to survive and thrive through the vagaries of evolution. And just how do they do this?...zip to page 1152 to find out.     

我国家庭旅馆业的发展现状及管理对策

我国旅游业在国家政策的大力支持下,取得了突飞猛进的发展。而作为旅游业的三大支柱产业食、住、行之一的住宿业该如何根据我国旅游业整体发展的需要,既能取得较大的发展,又能突出自身特色,是摆在我们面前的重要课题。文章在介绍国内外家庭旅馆业发展的基础上,分析说明了我国家庭旅馆业产生的必然性、发展现状及存在的问题,并就此有针对性的提出了一些管理对策,以供借鉴和参考。     

Successful transmission of a retrovirus depends on the commensal microbiota

To establish chronic infections, viruses must develop strategies to evade the host's immune responses. Many retroviruses, including mouse mammary tumor virus (MMTV), are transmitted most efficiently through mucosal surfaces rich in microbiota. We found that MMTV, when ingested by newborn mice, stimulates a state of unresponsiveness toward viral antigens. This process required the intestinal microbiota, as antibiotic-treated mice or germ-free mice did not transmit infectious virus to their offspring. MMTV-bound bacterial lipopolysaccharide triggered Toll-like receptor 4 and subsequent interleukin-6 (IL-6)-dependent induction of the inhibitory cytokine IL-10. Thus, MMTV has evolved to rely on the interaction with the microbiota to induce an immune evasion pathway. Together, these findings reveal the fundamental importance of commensal microbiota in viral infections.     

中国高等农业教育新农科建设的若干思考

中国迈向强国之路的冲锋号已经吹响。农业强国梦是中国梦的坚强支撑。中国高等农业教育站在了重要的历史节点上,处于一个新的历史机遇期,需要我们"农林人"思考如何建设好人民满意的高等农业教育。这就要求我们进一步解放思想,转变以往注重服务产业经济、培养专业技术人才的教育观念,深化教育教学改革,通过4个根本性的转变（从偏重服务产业经济向促进学生全面发展转变,从单学科割裂独立发展向多学科交叉融合发展转变,从专注专业教育向专业教育与通识教育高度融合转变,从专注知识本位向侧重个人本位转变）,探索实现农科学生全面发展与人生价值的新农科建设之路。     

Death and the ecological crisis

In this essay I discuss the ways in which not recognizing that the death of organisms plays a part in our food producing systems, distances us from life’s ecological processes and explore how this plays a role in devaluing the sources of our food. I argue that modern society’s deep separation from our agricultural systems play a part in our current ecological illiteracy.     

深化实验教学改革培养学生创新能力

本文分析了当前实验教学的现状及和存在的问题，阐述了更新教育观念、深化实验教学改革的必要性，提出了新型实验教学体系的构建步骤，并结合本校实际，就实验教学改革的具体做法及改革效果进行了分析和探讨。     

Neural mechanisms of visual attention: how top-down feedback highlights relevant locations

Attention helps us process potentially important objects by selectively increasing the activity of sensory neurons that represent the relevant locations and features of our environment. This selection process requires top-down feedback about what is important in our environment. We investigated how parietal cortical output influences neural activity in early sensory areas. Neural recordings were made simultaneously from the posterior parietal cortex and an earlier area in the visual pathway, the medial temporal area, of macaques performing a visual matching task. When the monkey selectively attended to a location, the timing of activities in the two regions became synchronized, with the parietal cortex leading the medial temporal area. Parietal neurons may thus selectively increase activity in earlier sensory areas to enable focused spatial attention.     

Why we don't get sick: the within-host population dynamics of bacterial infections

To pathogenic microparasites (viruses, bacteria, protozoa, or fungi), we and other mammals (living organisms at large) are little more than soft, thin-walled flasks of culture media. Almost every time we eat, brush our teeth, scrape our skin, have sex, get bitten by insects, and inhale, we are confronted with populations of microbes that are capable of colonizing the mucosa lining our orifices and alimentary tract and proliferating in fluids and cells within us. Nevertheless, we rarely get sick, much less succumb to these infections. The massive numbers of bacteria and other micro- and not-so-micro organisms that abound and replicate in our alimentary tract and cover our skin and the mucosa lining our orifices normally maintain their communities in seemingly peaceful coexistence with the somatic cells that define us. Why don't these microbes invade and proliferate in the culture media within the soft, thin-walled flask that envelops us? Why don't they cause disease and lead to our rapid demise?     

微博、微信在民办高校心理健康教育的运用分析

本文就主要对微博、微信的特点、民办高校大学生的心理特点、对民办高校心理健康教 育的影响,以及如何运用微博、微信做好民办高校心理健康教育工作做具体陈述。     

论网络环境下的写作与道德

随着计算机网络的发展,写作环境发生了很大变化。论述了网络对写作带来好处的同时,也对写作道德产生冲击,出现一些不良现象。论文在此基础上提出了如何适应网络下的写作环境,提高写作道德的策略。。     

小型水电站的发展与开发研究进展

水能资源由于其突出的优越性已得到世界各国普遍应用。我国水力资源丰富 ,尤其是小水电资源遍布各省区 ,这些可再生的水电资源的开发利用对农村能源起着非常重要的作用。从理论方法上对小水电的开发作了论述 ,对目前存在的不足进行了探讨     

Metagenomic analysis of the human distal gut microbiome

The human intestinal microbiota is composed of 10(13) to 10(14) microorganisms whose collective genome ("microbiome") contains at least 100 times as many genes as our own genome. We analyzed approximately 78 million base pairs of unique DNA sequence and 2062 polymerase chain reaction-amplified 16S ribosomal DNA sequences obtained from the fecal DNAs of two healthy adults. Using metabolic function analyses of identified genes, we compared our human genome with the average content of previously sequenced microbial genomes. Our microbiome has significantly enriched metabolism of glycans, amino acids, and xenobiotics; methanogenesis; and 2-methyl-d-erythritol 4-phosphate pathway-mediated biosynthesis of vitamins and isoprenoids. Thus, humans are superorganisms whose metabolism represents an amalgamation of microbial and human attributes.     

Compartmentalized control of skin immunity by resident commensals

Intestinal commensal bacteria induce protective and regulatory responses that maintain host-microbial mutualism. However, the contribution of tissue-resident commensals to immunity and inflammation at other barrier sites has not been addressed. We found that in mice, the skin microbiota have an autonomous role in controlling the local inflammatory milieu and tuning resident T lymphocyte function. Protective immunity to a cutaneous pathogen was found to be critically dependent on the skin microbiota but not the gut microbiota. Furthermore, skin commensals tuned the function of local T cells in a manner dependent on signaling downstream of the interleukin-1 receptor. These findings underscore the importance of the microbiota as a distinctive feature of tissue compartmentalization, and provide insight into mechanisms of immune system regulation by resident commensal niches in health and disease.     

日本检疫性贸易壁垒及我应对措施

通过对日本检疫性贸易壁垒的分析，我们应根据SPS协议的有关规定，采取必要措施，打破其检疫性贸易壁垒，促进我产品出口。