PPARs信号通路参与肠道菌群和棕色脂肪组织的代谢调控肥胖

背景:肠道菌群与棕色脂肪组织之间存在着复杂的调控机制和广泛联系,但是目前机制尚未阐明。目的:揭示棕色脂肪组织与肠道菌群间的潜在关系,为接下来的研究提供实验思路。方法:由第一作者应用计算机以“brown adipose tissue,intestinal flora,obesity,peroxisome proliferator activated receptor family”为英文检索词,以“棕色脂肪组织,肠道菌群,肥胖,过氧化物酶体增殖物激活受体家族”为中文检索词在PubMed、万方、维普、知网数据库中检索1994-01-01/2020-06-01的相关文献,并对文献的相关内容进一步筛选、归纳分析与总结,最终纳入38篇相关文献进行综述。结果与结论:①肠道菌群失调会影响过氧化物酶体增殖物激活受体(peroxisome proliferator-activated receptors,PPARs),PPARs又可以影响棕色脂肪组织的代谢进而调控肥胖;PPARα、PPARβ和PPARγ都与脂肪代谢有关,可以被相应的激活剂激活促进棕色脂肪组织的表达,其中PPARγ在肠道菌群和棕色脂肪组织中的联系最为密切,肠道菌群代谢的变化可以上调PPARγ的表达,从而激活棕色脂肪组织达到减肥的目的;②调节肠道菌群与棕色脂肪组织的关系可以治疗肥胖症;③从棕色脂肪组织、PPARs信号通路两者中研究抵抗肥胖的相关药物前景可观。     

产β 内酰胺酶葡萄球菌在临床标本中的检出及耐药性

目的了解某院产β 内酰胺酶葡萄球菌在临床标本中的检出及耐药现状，为防治葡萄球菌感染提供依据。方法回顾性分析该院2005-2010年临床各科送检标本分离的1 725株产β 内酰胺酶葡萄球菌的临床和实验室资料。结果近6年产β 内酰胺酶葡萄球菌总检出率为94.83%（1 725/1 819），各年度（2005-2010年）检出率分别为88.68%（94/106）、89.69%（174/194）、91.72%（155/169）、97.58%（242/248）、96.10%（591/615）、96.30%（469/487），有逐年上升趋势（χ2=51.11, P<0.01）；各菌种以松鼠葡萄球菌β 内酰胺酶阳性率最高（99.50%，198/199），耳葡萄球菌最低（80.37%，86/107），种间差异有统计学意义（χ2＝58.08，P<0.01）。药敏结果显示，除万古霉素、利奈唑烷、呋喃妥因和利福平外，产β 内酰胺酶葡萄球菌对青霉素、氨苄西林、氨苄西林/舒巴坦、苯唑西林、头孢唑林、环丙沙星、四环素、克林霉素、红霉素、庆大霉素和复方磺胺甲口恶唑呈高度耐药（耐药率51.74%～100.00%）和多重耐药，且产酶菌的耐药性均高于非产酶菌（χ2在7.00～485.39之间，P<0.01）。苯唑西林耐药菌株占产β 内酰胺酶金黄色葡萄球菌和凝固酶阴性葡萄球菌的72.86%和78.30%，是产酶葡萄球菌的主要组成菌群。结论产β 内酰胺酶葡萄球菌的高检出率和对临床常用抗菌药物的高耐药率形势严峻，加强对产酶细菌的监测，遏制其快速增长非常必要。     

Microbial life at ?13 °C in the brine of an ice-sealed Antarctic lake

The permanent ice cover of Lake Vida (Antarctica) encapsulates an extreme cryogenic brine ecosystem (−13 °C; salinity, 200). This aphotic ecosystem is anoxic and consists of a slightly acidic (pH 6.2) sodium chloride-dominated brine. Expeditions in 2005 and 2010 were conducted to investigate the biogeochemistry of Lake Vida’s brine system. A phylogenetically diverse and metabolically active Bacteria dominated microbial assemblage was observed in the brine. These bacteria live under very high levels of reduced metals, ammonia, molecular hydrogen (H₂), and dissolved organic carbon, as well as high concentrations of oxidized species of nitrogen (i.e., supersaturated nitrous oxide and ∼1 mmol⋅L⁻¹ nitrate) and sulfur (as sulfate). The existence of this system, with active biota, and a suite of reduced as well as oxidized compounds, is unusual given the millennial scale of its isolation from external sources of energy. The geochemistry of the brine suggests that abiotic brine-rock reactions may occur in this system and that the rich sources of dissolved electron acceptors prevent sulfate reduction and methanogenesis from being energetically favorable. The discovery of this ecosystem and the in situ biotic and abiotic processes occurring at low temperature provides a tractable system to study habitability of isolated terrestrial cryoenvironments (e.g., permafrost cryopegs and subglacial ecosystems), and is a potential analog for habitats on other icy worlds where water-rock reactions may cooccur with saline deposits and subsurface oceans.     

An exploration of the disease burden due to Cryptosporidium in consumed surface water for sub-Saharan Africa

The protozoan pathogen Cryptosporidium is an important cause of diarrhoeal disease, but in many contexts its burden remains uncertain. The Global Waterborne Pathogen model for Cryptosporidium (GloWPa-Crypto) predicts oocyst concentrations in surface water at 0.5 by 0.5° (longitude by latitude) resolution, allowing us to assess the burden specifically associated with the consumption of contaminated surface water at a large scale. In this study, data produced by the GloWPa-Crypto model were used in a quantitative microbial risk assessment (QMRA) for sub-Saharan Africa, one of the regions most severely affected by diarrhoeal disease. We first estimated the number of people consuming surface water in this region and assessed both direct consumption and consumption from a piped (treated) supply. The disease burden was expressed in disability adjusted life years (DALYs). We estimate an annual number of 4.3 × 10⁷ (95% uncertainty interval [UI] 7.4 × 10⁶–5.4 × 10⁷) cases which represent 1.6 × 10⁶ (95% UI 3.2 × 10⁵–2.3 × 10⁶) DALYs. Relative disease burden (DALYs per 100,000 persons) varies widely, ranging between 1.3 (95% UI 0.1–5.7) for Senegal and 1.0 × 10³ (95% UI 4.2 × 10²–1.4 × 10³) for Eswatini. Countries that carry the highest relative disease burden are primarily located in south and south-east sub-Saharan Africa and are characterised by a relatively high HIV/AIDS prevalence. Direct surface water consumption accounts for the vast majority of cases, but the results also point towards the importance of stable drinking water treatment performance. This is, to our knowledge, the first study to utilise modelled data on pathogen concentrations in a large scale QMRA. It demonstrates the potential value of such data in epidemiological research, particularly regarding disease aetiology.     

局限性侵袭性牙周炎患者早期全身应用抗生素的临床意义

目的:探讨即刻使用抗生素和延期使用抗生素对局限性侵袭性牙周炎患者临床指标的影响。方法:根据传统使用抗生素两个时间段,将82例患者分为两组,在根面刮治及平整术(SRP)术后立即使用抗生素组和3月复诊支持治疗后使用抗生素组,回顾性研究评价两组临床指标的变化。结果:两组在6月时临床指标均显著改善,差异有统计学意义(P<0.01),立即组3月、6月时间段较基线比较显著改善,差异有统计学意义(P<0.01),延迟组3月较基线改善无明显统计学差异。结论:对局限性侵袭性牙周炎早期使用抗生素对控制病情非常有利。     

The Queuine Micronutrient: Charting a Course from Microbe to Man

Micronutrients from the diet and gut microbiota are essential to human health and wellbeing. Arguably, among the most intriguing and enigmatic of these micronutrients is queuine, an elaborate 7-deazaguanine derivative made exclusively by eubacteria and salvaged by animal, plant and fungal species. In eubacteria and eukaryotes, queuine is found as the sugar nucleotide queuosine within the anticodon loop of transfer RNA isoacceptors for the amino acids tyrosine, asparagine, aspartic acid and histidine. The physiological requirement for the ancient queuine molecule and queuosine modified transfer RNA has been the subject of varied scientific interrogations for over four decades, establishing relationships to development, proliferation, metabolism, cancer, and tyrosine biosynthesis in eukaryotes and to invasion and proliferation in pathogenic bacteria, in addition to ribosomal frameshifting in viruses. These varied effects may be rationalized by an important, if ill-defined, contribution to protein translation or may manifest from other presently unidentified mechanisms. This article will examine the current understanding of queuine uptake, tRNA incorporation and salvage by eukaryotic organisms and consider some of the physiological consequence arising from deficiency in this elusive and lesser-recognized micronutrient.     

参苓白术散加减对β-内酰胺类抗菌药物性腹泻患儿免疫功能及肠道菌群的分析

目的探讨参苓白术散加减对β-内酰胺类抗菌药物性腹泻(AAD)患儿免疫功能及肠道菌群的分析。方法选取2017年2月~2018年9月收治的90例β-内酰胺类抗菌药物性腹泻患儿作为研究对象,使用随机数表法将其随机等分为研究组与对照组,对照组45例给予常规西医治疗,研究组在对照组治疗基础上给予参苓白术散加减治疗,观察其对两组患儿免疫功能及肠道菌群的影响,临床疗效情况。结果研究组的临床疗效情况显著优于对照组,差异有统计学意义(P<0.05);两组治疗后其CD4+/CD8+、CD4+、IgA、IgG免疫功能指标均得到显著改善,研究组患儿的各项指标改善度明显优于对照组,差异有统计学意义(P<0.05);两组治疗后PCT、血清二胺氧化酶、sIgA含量及粪便球/杆菌比例水平均有所改善,研究组的改善情况明显优于对照组,差异有统计学意义(P<0.05)。结论参苓白术散加减治疗对β-内酰胺类抗菌药物性腹泻患儿的疗效明显,改善免疫功能和肠道菌群。     

Some are more equal than others

The microbial communities found in the mammalian large intestine and rumen efficiently degrade many recalcitrant substrates that are resistant to the host’s digestive enzymes. These communities are known from molecular profiling to be highly diverse at the species and strain level, but it may be that only certain specialized organisms (“keystone species”) have the ability to initiate degradation of such substrates, thus releasing energy on which the rest of the community depends. We have recently reported that Ruminococcus bromii has a superior ability to degrade certain forms of particulate resistant starch (RS) when compared with other highly abundant species of amylolytic bacteria found in the human colon and have presented evidence that this bacterium provides an example of a keystone species within the microbial community with respect to RS fermentation. The concept of keystone species can be equally relevant to other activities, e.g., those involved in stabilizing the community.