以肠道菌群为靶向的粪菌移植法及其在畜牧业的应用潜能

肠道微生物与宿主机体健康息息相关。粪便微生物移植(又称为粪菌移植,fecal microbiota transplantation,FMT)通过将健康供体粪便中的完整肠道菌群移入肠道微生态失衡的患者胃肠道内,经肠道菌群重构、恢复至正常状态。用FMT治疗某些肠道疾病如复发性艰难梭菌感染、溃疡性结肠炎、肠易激综合症、克罗恩病效果显著,且可能对因肠道菌群紊乱引起的肠道外疾病的治疗有潜在价值。本文主要对FMT技术的发展进程、在疾病上的研究以及在畜牧业上的应用潜能进行综述,并分析其应用的制约因素。     

粪菌移植的临床应用研究进展

人类的肠道菌群种类及数量众多,目前被认为是人体的一个特殊器官。肠道菌群在维持肠道的正常生理功能和机体免疫功能方面发挥了重要作用,肠道微生态失衡与炎症性肠病、代谢综合征、肝病、心血管疾病、精神疾病、关节炎等多种肠内外疾病密切相关,纠正肠道微生态失衡将有助于上述疾病的治疗。粪菌移植(fecal microbiota transplantation,FMT)是指将健康人粪便中的功能菌群移植到患者胃肠道内,重建具有正常功能的肠道菌群,以达到治疗肠道和肠道外疾病的目的。目前报道FMT已应用于艰难梭菌感染、炎症性肠病、肠易激综合征、代谢综合征等多种疾病的治疗中。本文就FMT的临床应用现状作一综述。     

粪菌移植治疗难治性肠道疾病的临床应用

人体肠道内菌群结构失衡与肠道疾病的发生发展密切相关。粪菌移植可以纠正肠道菌群结构失调,早在东晋时期,已有相关的临床应用记载。近年来,粪菌移植已成功应用于部分肠道菌群失调相关的难治性肠道疾病的治疗,如复发性难辨梭状芽孢杆菌感染、炎症性肠病、肠易激综合征、慢性功能性便秘等,均取得了较好的疗效。文章对粪菌移植治疗难治性肠道疾病的相关临床研究进行了文献回顾,重点分析了粪菌移植治疗难治性肠道疾病的难点和对策,并探讨了粪菌移植的应用前景。     

从粪菌移植到下一代益生菌:挑战与进展CSCD

细菌、真菌、病毒和原生动物等微生物生活在肠道中,共同组成肠道微生物群。其中,细菌在肠道微生物群中占主导地位。肠道菌群对于维持肠道及全身健康至关重要,肠道微生态失调与人类多种疾病相关。调节失衡的肠道菌群有助于这些疾病的治疗,粪菌移植因在治疗艰难梭菌感染方面取得成功而备受关注。许多临床试验证实了粪菌移植在治疗其他肠道疾病及全身疾病方面具有潜力,但疗效却因人而异,具体机制不明。研究者们致力于从健康供体肠道菌群中寻找真正具有“益生”作用的新型细菌,这些细菌被称为下一代益生菌。     

粪菌移植治疗艰难梭菌感染的研究进展

艰难梭菌感染(Clostridium difficile infection,CDI)是院内抗生素相关性腹泻的最重要因素之一,其主要临床表现包括血便、腹泻、中毒性巨结肠、伪膜性肠炎等。近年来,CDI发病率、复发率、死亡率和治疗费用均明显增加,但其各种治疗方法均有局限性,尤其是抗生素治疗复发性艰难梭菌感染已面临许多棘手问题。目前证实肠道菌群失调和CDI感染关系密切,肠道菌群紊乱后导致艰难梭菌过度繁殖并释放毒素,可导致艰难梭菌感染。粪菌移植作为重建肠道菌群的重要方式,已成为复发性、难治性艰难梭菌感染最有效的治疗方式之一,不良反应极少。本文就国内外粪菌移植治疗艰难梭菌感染的研究进展作一综述。     

粪菌移植途径的临床应用现状

人体肠道内寄居着数量庞大、种类繁多的微生物,形成肠道微生态稳态,而肠道微生态失衡与多种肠内、肠外疾病相关。随着人们对肠道菌群在宿主健康及疾病中作用的深入认识,粪菌移植(faecal microbiota transplantation, FMT)被给予厚望,其作为重建肠道菌群的有效手段,已成功应用于艰难梭菌感染(Clostridioides difficile infection, CDI)等疾病的治疗和探索性研究,并被认为是近年的突破性医学进展。随着近几年FMT研究的深入,人们发现FMT对各系统疾病皆有潜在的治疗作用。在1990年之前,菌群移植都是经灌肠实施,近几年随着粪菌移植研究的深入,粪菌移植途径也呈多样化发展。本文对粪菌移植途径、临床应用和存在的问题等作一综述。     

益生菌在炎症性肠病治疗中的研究进展

益生菌（Probiotics）是一类能够促进肠道微生物菌群平衡,对宿主健康或生理功能产生有益作用的活性微生物。目前广泛应用于生命健康领域、科学研究、生物工程、工农业以及食品安全。大量国内外研究表明益生菌在降血压、降血糖、降血脂、抗过敏、抗炎、调节免疫、维持肠道菌群平衡等方面具有积极作用。炎症性肠病的病因和发病机制尚未完全明确,现多认为与遗传、环境、感染、免疫以及肠道微生物多因素相互作用有关。益生菌通过多种机制介导,在临床治疗炎症性肠病中扮演着重要角色。     

粪菌移植在儿童炎症性肠病中的应用

炎症性肠病(IBD)是一种病因尚不明确的非特异性肠道炎症性疾病。越来越多的证据表明肠道菌群失调与IBD的发生发展密切相关。粪菌移植是通过各种方式将健康捐赠者的粪便菌群移植入患者消化道内,旨在重建患者肠道菌群从而达到对肠道内外疾病治疗的目的。肠道微生物稳态及失调在疾病发生发展中发挥作用,其中包括炎症性肠病(IBD)。越来越多的研究报道了FMT在IBD中的治疗作用,现主要阐述粪菌移植在儿童IBD中的应用。     

炎症性肠病与艰难梭菌感染相关性研究的文献计量学和可视化分析

【背景】近年来,炎症性肠病患者中艰难梭菌（Clostridium difficile）感染率逐年上升,受到国内外学者广泛关注。我国在该领域的研究起步较晚,但患者数量众多,学习国际上对于炎症性肠病合并艰难梭菌感染的研究,对推动我国在该领域的深入发展具有重要意义。【目的】通过文献计量和可视化分析帮助研究者把握炎症性肠病与艰难梭菌感染相关性研究中的研究主题、方向、热点与前沿。【方法】同时检索Web of Science （WOS）中Science Citation Index Expanded （SCI-E）和CNKI中收录的关于炎症性肠病和艰难梭菌的相关文献,应用CiteSpace 6.2.2r软件进行国家/地区、机构、作者、关键词共现及被引文献、期刊共被引分析,同时进行可视化分析。【结果】经过数据检索和查重,最终可供分析的文献为WOS数据库1 030篇、CNKI数据库80篇。全球范围内,发文最多的国家是美国,主要研究机构有Harvard University、University of California System和Mayo Clinic等,高产作者有Khanna S、Shen B和Ananthakrishnan AN等,高频关键词包括Inflammatory bowel disease、Ulcerative colitis、Clostridium difficile、Clostridium difficile infection和Crohn’s disease等,聚类方向有#0 Diarrhea、#1 Ulcerative colitis、#2 Probiotics、#3 Pouchitis、#4 Gut microbiota、#5 Fecal microbiota transplantation、#6 Depression、#7 Entamoeba histolytica、#8 Pseudomembranous colitis、#9 Clostridium difficile和#10 Clindamycin。国内主要研究机构有南方医科大学和河北医科大学,高产作者有王浦、王斯淇等,高频关键词包括粪菌移植、艰难梭菌、肠道菌群、危险因素和克罗恩病等,聚类方向有#0艰难梭菌、#1益生菌、#2危险因素、#3腹泻和#4粪菌移植。【结论】利用CiteSpace软件对炎症性肠病和艰难梭菌感染相关性研究进行计量及可视化分析可知,该方向仍得到全球各医疗机构及研究者的关注,腹泻及粪菌移植这两个关键词分别代表了WOS数据库和CNKI数据库关于炎症性肠病合并艰难梭菌感染研究的热点。     

粪菌移植在临床治疗中的研究进展

粪菌移植的历史可以追溯到中国东晋时期。大量研究证实粪菌移植有可能成为许多疾病的有效治疗方法,现已逐渐应用于临床上并取得较好的疗效。粪菌移植可以通过增加短链脂肪酸,特别是丁酸盐的产量来减少肠道通透性,从而降低疾病的严重程度,这有助于维持上皮屏障的完整性。粪菌移植还可以通过抑制Th1分化、T细胞活性、白细胞粘附和炎症因子的产生来恢复免疫生态失调。目前对粪菌移植的研究主要集中在治疗艰难梭菌感染,但其他领域对粪菌移植研究的热情也日益高涨,如用于治疗炎症性肠病、代谢综合征和肠易激综合征等。本文对最新的粪菌移植在临床治疗中的研究进展作一综述。     

Race and Racism in America and in Anthropology

Race in North America: Origin and Evolution of a Worldview . Audrey Smedley
Anthropology and Race . Eugenia Shanklin     

Degradation and conversion of somatostatin in normal and diabetic rats in vivo and in vitro

Plasma somatostatin-like immunoreactivity in the portal and jugular veins of streptozotocin diabetic rats was compared with that in normal control rats. In the diabetic group, somatostatin levels in the portal (p less than 0.05) and jugular (p less than 0.01) veins were both elevated compared with those in the control group. Moreover, the degree of elevation was greater in the jugular vein than in the portal vein. To further investigate the role of the liver in the clearance of somatostatin-28 in vivo, 2 micrograms of somatostatin-28 was administered as a bolus into the external jugular vein of intact and functionally hepatectomized rats. The mean half-time of somatostatin-28 was significantly longer in intact diabetic rats than in controls (p less than 0.05). The functional hepatectomy did not cause a significant difference in the half-time in diabetic rats but made it longer in control rats. These results suggest that the longer half-time of somatostatin-28 in diabetic rats in vivo is due to its slower hepatic clearance. The hepatic clearance of somatostatin-28 and somatostatin-14 was further studied in vitro using a recirculating liver perfusion method. The hepatic clearance of 1.2 nM of either somatostatin-28 or somatostatin-14 was significantly lower in diabetic rats than in controls (p less than 0.01). This indicates that elevated plasma somatostatin levels in diabetic rats are caused at least in part by decreased hepatic clearance of somatostatin.(ABSTRACT TRUNCATED AT 250 WORDS)     

Variation in infectivity and aggressiveness in space and time in wild host-pathogen systems: causes and consequences

Variation in host resistance and in the ability of pathogens to infect and grow (i.e. pathogenicity) is important as it provides the raw material for antagonistic (co)evolution and therefore underlies risks of disease spread, disease evolution and host shifts. Moreover, the distribution of this variation in space and time may inform us about the mode of coevolutionary selection (arms race vs. fluctuating selection dynamics) and the relative roles of G × G interactions, gene flow, selection and genetic drift in shaping coevolutionary processes. Although variation in host resistance has recently been reviewed, little is known about overall patterns in the frequency and scale of variation in pathogenicity, particularly in natural systems. Using 48 studies from 30 distinct host–pathogen systems, this review demonstrates that variation in pathogenicity is ubiquitous across multiple spatial and temporal scales. Quantitative analysis of a subset of extensively studied plant–pathogen systems shows that the magnitude of within‐population variation in pathogenicity is large relative to among‐population variation and that the distribution of pathogenicity partly mirrors the distribution of host resistance. At least part of the variation in pathogenicity found at a given spatial scale is adaptive, as evidenced by studies that have examined local adaptation at scales ranging from single hosts through metapopulations to entire continents and – to a lesser extent – by comparisons of pathogenicity with neutral genetic variation. Together, these results support coevolutionary selection through fluctuating selection dynamics. We end by outlining several promising directions for future research.     

Aminoacylation in Sulfolobus acidocaldarius and in methanogenic and halophilic archaebacteria

Abstract Phenylalanyl-tRNA synthetase (PRS) from the sulphur-metabolizing thermoacidophilic archaebacterium Sulfolobus acidocaldarius has been purified 150-fold using different chromatographic steps. The enzyme has a M _r of 270 000 and exhibits considerable thermostability in a temperature range up to 90°C with optimal activity at 70°C. Conservation of antigenic determinants could not be detected by antibodies against various PRS of all primary kingdoms. As a further means to detect traits of phylogenetic relationship, the cross-species reactivity between PRS and tRNAs of organisms from the three branches of archaebacteria and from all primary kingdoms reveals the group character of all 3 branches of the archaebacterial domain, the sulphur-metabolizing, methanogenic and halophilic archaebacteria.     

Electroejaculation in chimpanzees and gorillas and artificial insemination in chimpanzees

Electroejaculation was performed in 3 chimpanzees, 1 pygmy chimpanzee, and 2 gorillas with an instrument that delivers a modified sine wave current with a frequency of 24 Hz. The current stimuli were applied by a rectal probe with longitudinal electrodes. The electrical parameters varied from 6 to 12 V and from 30 to 40 mA for response of erection and lay between 8 and 18 V and between 40 and 145 mA during semen emission. Eleven chimpanzee semen samples showed the following data (x ± SD): total volume 1.9 ± 1.3 ml, volume of the liquid fraction 0.3 ± 0.2 ml, spermatozoa per ejaculate 743 ± 376 × 10⁶, sperm motility 52.7 ± 9.6%, morphologically abnormal spermatozoa 12.2 ± 7.5%. From an adult gorilla, three semen samples were collected, in each case without spermatozoa. The electrostimulation of a 6-year-old gorilla led to an erection, but not to semen emission. Three female chimpanzees were inseminated with fresh or frozen semen, each of them within three different estrous cycles. None of these inseminations led to a pregnancy.     

Advances in purine and pyrimidine metabolism in health and diseases

ABSTRACT

In June, 2015, the Purine and Pyrimidine Society organized the 16th biennial symposium on Purine and Pyrimidine metabolism at the Faculty House of Columbia University, New York City. This exciting meeting focused on these important molecules, new developments in inborn errors of metabolism; therapeutic analogs. In addition, the biochemistry of mammalian and non-mammalian systems were discussed. Due to significant advances in molecular medicine, the boundaries between clinical and basic sciences have merged into exciting translational research, of which a small portion was highlighted in the presymposium.     

Trajectories and Constraints in Brain Evolution in Primates and Cetaceans

A negative allometric relationship between body mass (BM) and brain size (BS) can be observed for many vertebrate groups. In the past decades, researchers have proposed several hypotheses to explain this finding, but none is definitive and some are possibly not mutually exclusive. Certain species diverge markedly (positively or negatively) from the mean of the ratio BM/BS expected for a particular taxonomic group. It is possible to define encephalization quotient (EQ) as the ratio between the actual BS and the expected brain size. Several cetacean species show higher EQs compared to all primates, except modern humans. The process that led to big brains in primates and cetaceans produced different trajectories, as shown by the organizational differences observed in every encephalic district (e.g., the cortex). However, these two groups both convergently developed complex cognitive abilities. The comparative study on the trajectories through which the encephalization process has independently evolved in primates and cetaceans allows a critical appraisal of the causes, the time and the mode of quantitative and qualitative development of the brain in our species and in the hominid evolutionary lineage.