肝癌微血管浸润相关长链非编码RNA(lncRNA-MVIH)在结直肠癌中的表达

为了探讨长链非编码RNA肝癌微血管浸润相关mRNA(MVIH-lncRNA)在结直肠癌中的表达及其临床意义。本研究采用实时荧光定量PCR(RT-q PCR)检测MVIH-lncRNA在44例结直肠癌组织、44例癌旁组织和13例正常结肠组织中表达。研究结果表明:MVIH-lncRNA在结直肠癌组织中的表达显著高于癌旁组织(p0.001)和正常结肠组织(p0.001),并且MVIH-lncRNA的表达在正常结肠组织、癌旁组织、结直肠癌组织中呈递增趋势(p0.001)。高表达MVIH-lncRNA与淋巴结转移相关,而与年龄、性别、肿瘤大小、肿瘤分化不相关;MVIH-lncRNA表达上调患者生存时间更短(p=0.034),其在结直肠中高表达提示预后不良。本研究的结果表明MVIH-lncRNA在结直肠癌的早期诊断、预后评价中的具有重要的意义,为进一步研究MVIH-lncRNA在结直肠癌的发生发展中的分子机理奠定了研究基础。     

上消化道钡餐检查对十二指肠憩室的诊断分析

目的探讨十二指肠憩室的X线上消化道钡餐诊断价值。方法对我院收治的74例十二指肠憩室患者的上消化道钡餐检查结果进行回顾性分析。结果 74例十二指肠憩室患者中共检出80个憩室,其中单发憩室70例,多发憩室4例,憩室大小在0.5cm×0.4cm~5.8cm×4.1cm。结论上消化道钡餐检查精确度较高,是十二指肠憩室临床诊断的首选方法,对大多数患者均适用,且该法安全、简便、易行,具有重要的临床应用价值。     

人肠道梭菌和甲烷马赛球菌协同代谢甜菜碱和胆碱产甲烷研究

【目的】根据人肠道富含胆碱和甜菜碱,同时肠道微生物组中具有裂解胆碱和还原甜菜碱产三甲胺的细菌,以及利用三甲胺产甲烷的古菌,本研究探讨肠道细菌与古菌协同代谢甜菜碱和胆碱产甲烷的可能性。【方法】调查不同年龄段人群粪便中的16S rRNA基因多样性,分析肠道中古菌的菌群组成;利用定量PCR(quantitativePCR,qPCR)定量甲烷马赛球菌(Methanomassiliicoccus)特异的甲醇甲基转移酶基因mtaB和甲烷八叠球菌(Methanosarcina)及细菌的16SrRNA基因拷贝数,分析肠道中甲基营养型产甲烷古菌及总细菌的含量;宏基因组组装基因组(metagenome-assembled genomes, MAGs)分析携带甜菜碱还原酶基因grdH和胆碱裂解酶基因cutC的细菌组成。从粪便中分离代谢甜菜碱及胆碱产生三甲胺的细菌,并与分离自人肠道的甲烷马赛球菌构建共培养物,测定其协同转化甜菜碱和胆碱产甲烷的能力。【结果】年轻人粪便中含有甲烷杆菌科(Methanobacteriaceae,82.16%)的甲烷短杆菌属(Methanobrevibacter,49.18%)和甲烷...     

小鼠粪便及肠道各部位内容物细菌群落结构差异分析

目的分析小鼠粪便及肠道各部位内容物细菌群落结构差异,探讨粪便取样研究肠道微生物与疾病关系的科学性和客观性,为相关实验设计提供参考。方法利用末端限制性片段长度多态性(T-RFLP)、变性梯度凝胶电泳(DGGE)和荧光定量PCR(q PCR)技术对BALB/c小鼠肠道不同部位(十二指肠、空肠、回肠、盲肠、结肠和直肠)内容物及粪便中细菌群落组成和丰度进行比较,分析细菌群落在小鼠粪便及肠道各部位的分布差异。结果粪便与直肠、结肠中优势片段均为244、255 bp和449 bp,而小肠内容物(十二指肠、空肠及回肠)的优势片段则为60、73、261、268 bp和272 bp,且小肠各部位之间细菌群落结构差异较大;十二指肠和空肠内容物中的细菌丰度较低,分别为6.9 log(copies)/g和8.3 log(copies)/g,而粪便中细菌丰度高达11.8 log(copies)/g,约2倍于十二指肠细菌丰度,显著高于十二指肠和空肠(P0.05),与大肠各部位及回肠内容物细菌丰度相当,差异不显著(P0.05)。结论大肠各部位内容物和粪便的细菌群落结构相似,个体差异较小肠小,适合通过粪便取样进行大肠部位特别是结直肠的肠道微生态与某些疾病的相关分析。     

瘤胃降解粗纤维产甲烷的厌氧真菌与甲烷菌共培养物的分离鉴定

【目的】本试验从瘤胃中分离鉴定降解粗纤维产甲烷的厌氧真菌与甲烷菌共培养物,为深入探究甲烷菌对厌氧真菌代谢途径的影响及相关调节机制奠定基础。【方法】利用厌氧滚管技术从荷斯坦奶牛瘤胃内容物中分离厌氧真菌与甲烷菌共培养物,通过形态学观察和DAPI染色以及甲烷菌16S rRNA基因序列分析方法分别对厌氧真菌及甲烷菌进行鉴定。【结果】从荷斯坦奶牛瘤胃中共分离到28株厌氧真菌与甲烷菌共培养物。共培养物中的厌氧真菌均为单中心菌株,分别属于Piromyces,Neocallimastix和Caeomyces属,所占百分比为53.57%,42.86%及3.57%。甲烷菌16S rRNA基因序列分析结果表明,共培养物中的甲烷菌均为甲烷短杆菌。本研究共获得四种不同的厌氧真菌与甲烷菌组合,分别为Piromyces/类Methanobrevibacter olleyae菌株,Neocallimastix/类Methanobrevibacter olleyae菌株,Neocallimastix/类Methanobrevibacter thaueri菌株及Caecomyces/类Methanobrevibacter olleyae菌株,分别占总数的53.57%,39.29%,3.57%及3.57%。【结论】分离得到的28株厌氧真菌和甲烷菌共培养物中,占优势的为具有丰富丝状假根的厌氧真菌Piromyces和Neocallimastix以及类Methanobrevibacter olleyae属的甲烷短杆菌。本研究为进一步研究瘤胃内厌氧真菌与甲烷菌相互代谢关系奠定基础。     

人肠道梭菌和甲烷马赛球菌协同代谢甜菜碱和胆碱产甲烷研究

【目的】根据人肠道富含胆碱和甜菜碱,同时肠道微生物组中具有裂解胆碱和还原甜菜碱产三甲胺的细菌,以及利用三甲胺产甲烷的古菌,本研究探讨肠道细菌与古菌协同代谢甜菜碱和胆碱产甲烷的可能性。【方法】调查不同年龄段人群粪便中的16S rRNA基因多样性,分析肠道中古菌的菌群组成;利用定量PCR(quantitative PCR,qPCR)定量甲烷马赛球菌(Methanomassiliicoccus)特异的甲醇甲基转移酶基因mtaB和甲烷八叠球菌(Methanosarcina)及细菌的16S rRNA基因拷贝数,分析肠道中甲基营养型产甲烷古菌及总细菌的含量;宏基因组组装基因组(metagenome-assembled genomes,MAGs)分析携带甜菜碱还原酶基因grdH和胆碱裂解酶基因cutC的细菌组成。从粪便中分离代谢甜菜碱及胆碱产生三甲胺的细菌,并与分离自人肠道的甲烷马赛球菌构建共培养物,测定其协同转化甜菜碱和胆碱产甲烷的能力。【结果】年轻人粪便中含有甲烷杆菌科(Methanobacteriaceae,82.16%)的甲烷短杆菌属(Methanobrevibacter,49.18%)和甲烷杆菌属(Methanobacterium,33.34%)、甲基营养型的甲烷八叠球菌科(Methanosarcinaceae,5.67%)的甲烷八叠球菌属(Methanosarcina,5.70%),以及甲烷马赛球菌科(Methanomassiliicoccaceae,3.13%)的甲烷马赛球菌属(Methanomassiliicoccus,3.14%)。而中老年人粪便中的甲烷古菌多样性较低,也未检测到甲烷马赛球菌。qPCR定量分析显示年轻人比中老年人肠道的总古菌含量高3.11倍,其中甲烷马赛球菌高6.53倍、甲烷八叠球菌高5.52倍,总细菌含量高2.90倍。宏基因组分析组装了229个细菌基因组,其中42个携带基因grdH和cutC,这些细菌属于毛螺菌科(Lachnospiraceae)、肠杆菌科(Enterobacteriaceae)和梭菌科(Clostridiaceae)等。从粪便中分离到恶名梭菌(Clostridium malenominatum)B8,菌株B8与卢米尼甲烷马赛球菌(Methanomassiliicoccus luminyensis)B10共培养物可降解47.03%的甜菜碱和25.83%胆碱,并产生甲烷,在培养液中检测到三甲胺先积累后被降解。【结论】人肠道细菌恶名梭菌B8和卢米尼甲烷马赛球菌B10可协同代谢甜菜碱和胆碱产甲烷,推测它们在人肠道中可将部分食物中的甜菜碱和胆碱代谢产生甲烷。     

慢性腹痛患儿C~(13)-尿素呼气试验与胃镜检查的临床意义

目的了解慢性腹痛患儿幽门螺杆菌(H.pylori)的感染状态及幽门螺杆菌感染患儿内镜下表现的特点。方法应用C13尿素呼气试验,对905例以慢性腹痛为主要症状的患儿进行检测,对C13呼气试验阳性者进行电子胃镜检查。结果905例慢性腹痛患儿中H.pylori呈阳性185例(20.44%),随年龄增长,其H.pylori阳性率升高,学年组已达高峰。对H.pylori阳性者进行胃镜检查结果显示十二指肠隆起病变47例占25.40%,结节性胃炎41例占22.1%,慢性浅表性`胃炎38例占20.5%,结节性胃炎伴十二指肠隆起病变23例占12.43%,十二指肠球部溃疡23例占12.4%。胃溃疡7例,占3.7%(其中包括1例复合性溃疡),结节性胃炎伴十二指肠炎6例,占3.2%。结论H.pylori感染为小儿慢性腹痛的主要原因之一,也是导致慢性胃炎及消化性溃疡的主要原因之一。C13尿素呼气试验方便,快速,无痛苦,无放射性,是一较好的H.pylori检测方法;对既有消化道症状同时C13呼气试验阳性者进行胃镜检查能够协助临床诊断及治疗。     

开放条件下高聚β-羟基丁酸酯含量的甲烷氧化混合菌群的富集

目的:在开放条件下以甲烷为底物富集高聚β-羟基丁酸酯(PHB)含量的甲烷氧化菌群,获得能够利用低成本碳源高产PHB的菌种。方法:采用丰盛-饥饿模式间歇供料,以甲烷为底物,好氧开放式培养甲烷氧化混合菌群,利用苏丹黑染色法动态检测丰盛和饥饿阶段胞内PHB含量的变化,以此为基础考察丰盛-饥饿期比例对富集高PHB含量的甲烷氧化菌群的影响。结果:丰盛-饥饿期比例为1∶3时,微生物PHB含量从17.7%增加到35.5%,且开放培养过程中菌群结构稳定。结论:通过丰盛-饥饿模式间歇供料开放式培养所得的高PHB含量的稳定的甲烷氧化菌群,具有工业生产PHB的应用价值。     

微生物厌氧甲烷氧化反硝化研究进展

厌氧甲烷氧化反硝化过程(Denitrifying anaerobic methane oxidation,DAMO)以甲烷为电子供体进行反硝化作用,在实现废水脱氮处理的同时,可有效削减温室气体甲烷的排放,从而减缓全球温室效应。相关机制研究集中在逆向产甲烷途径耦合反硝化和亚硝酸盐依赖型厌氧甲烷氧化(nitrite-dependent anaerobic methane oxidation,n-damo)两个方面。鉴于厌氧甲烷氧化反硝化过程对全球碳氮物质循环的重要意义,本文对近年来厌氧甲烷氧化反硝化过程的研究进展进行了概述,着重阐述了有关厌氧甲烷氧化反硝化微生物富集培养物,特别是含Candidatus Methylomirabilis oxyfera(M.oxyfera)富集培养物的微生物特性、甲烷氧化反硝化的机理以及影响因子。在此基础上,探讨了厌氧甲烷氧化反硝化过程未来的研究方向和工业化应用前景。     

一种厌氧真菌共培养甲烷菌株的分离及其甲烷生产特性解析

【背景】开发生物甲烷资源是减轻化石燃料供求紧张的有效措施,而秸秆类原料的预处理及甲烷生产方法需要不断创新,从而进一步满足可持续发展。厌氧真菌与甲烷菌共培养能够通过假根侵入及纤维降解酶双重预处理秸秆并生产甲烷,但目前全世界被报道的骆驼胃肠道来源的厌氧真菌分离培养物仅有1株。【目的】从新疆准噶尔双峰驼瘤胃内容物中分离出新型厌氧真菌和甲烷菌共培养物,研究其在降解秸秆并联合生产生物甲烷方面的应用潜力。【方法】采用Hungate滚管纯化技术将从骆驼胃肠道中分离的厌氧真菌和甲烷菌共培养,对其进行形态学及分子学鉴定,随后厌氧发酵5种底物(稻秸、芦苇、构树叶、苜蓿秆和草木樨),研究产甲烷量、降解效果及主要代谢产物等方面的特性。【结果】筛选到的共培养物中的厌氧真菌为Oontomyces sp. CR1,甲烷菌为Methanobrevibacter sp. CR1。其在降解稻秸时表现出最高的木聚糖酶酶活力(21.64 IU/mL)及甲烷产量(143.39 mL/g-DM),甲烷生产特性较分离自其他动物宿主的厌氧真菌共培养物更优。【结论】共培养厌氧真菌与甲烷菌菌株CR1是一种新型高效降解菌株资源,其在利用木质纤维素生物质生产生物甲烷方面具有良好的应用前景。     

Increase in colonic methanogens and total anaerobes in aging rats

Methanogens are present in the colons of our local Wistar rat colony. We studied the changes in concentrations of their fecal methanogenic and nonmethanogenic bacteria with age as a model of the development of these communities in humans. We found that the predominant methanogen in the rats is a Methanobrevibacter species. The log of the concentration of total anaerobes increased from 9.8/g (dry weight) at 3.0 weeks of age (shortly after weaning) to 10.7/g (dry weight) at 96 weeks (shortly before the end of the life span). In contrast, the log concentration of methanogens increased from 5.5 to 9/g (dry weight) during the same time period. Therefore, methanogens increased as a percentage of the total anaerobes from 0.005% at 3.0 weeks to 2.0% at 96 weeks. About 12 doublings of the methanogenic population and 3.3 doublings of the nonmethanogenic population took place from weaning until death. The slow increase in the ratio of methanogens to total anaerobes with age followed the same pattern in cecal contents as found in feces. There were no relationships between animal weights or fecal outputs and the increase in total anaerobe and methanogen concentrations in feces. A possible explanation for the slow increase in the Methanobrevibacter species in Wistar rats with age is a gradual shifting of the use of electrons from the reduction of CO2 to acetate by acetogens to the reduction of CO2 to CH4. The results provide the first evidence for an age-related change in the nonmethanogenic bacteria of the colon and supporting microbiological evidence for physiological studies that have shown age-related increases in colonic methane production in humans.     

Development of a fecal occult blood test using a monoclonal antibody to haptoglobin

Monoclonal antibodies (mAbs) were produced to human haptoglobin by immunising with fecal extracts from patients with colon cancer. An enzyme-linked immunosorbent assay was developed with one of the mAbs (FE14.1), and its ability to diagnose colorectal carcinoma evaluated. Patients with colorectal cancer were positive (43/46 = 93.5%) compared to normal individuals (4/211 = 1.9%). The assay has a specificity 93.5% and sensitivity 98.1% and has several advantages over current fecal occult blood tests. The test is potentially useful for bowel cancer diagnosis and to quantitate the level of haptoglobin in other body fluids such as urine and in effusions.     

Increase in colonic methanogens and total anaerobes in aging rats.

Methanogens are present in the colons of our local Wistar rat colony. We studied the changes in concentrations of their fecal methanogenic and nonmethanogenic bacteria with age as a model of the development of these communities in humans. We found that the predominant methanogen in the rats is a Methanobrevibacter species. The log of the concentration of total anaerobes increased from 9.8/g (dry weight) at 3.0 weeks of age (shortly after weaning) to 10.7/g (dry weight) at 96 weeks (shortly before the end of the life span). In contrast, the log concentration of methanogens increased from 5.5 to 9/g (dry weight) during the same time period. Therefore, methanogens increased as a percentage of the total anaerobes from 0.005% at 3.0 weeks to 2.0% at 96 weeks. About 12 doublings of the methanogenic population and 3.3 doublings of the nonmethanogenic population took place from weaning until death. The slow increase in the ratio of methanogens to total anaerobes with age followed the same pattern in cecal contents as found in feces. There were no relationships between animal weights or fecal outputs and the increase in total anaerobe and methanogen concentrations in feces. A possible explanation for the slow increase in the Methanobrevibacter species in Wistar rats with age is a gradual shifting of the use of electrons from the reduction of CO2 to acetate by acetogens to the reduction of CO2 to CH4. The results provide the first evidence for an age-related change in the nonmethanogenic bacteria of the colon and supporting microbiological evidence for physiological studies that have shown age-related increases in colonic methane production in humans.     

Methanogenic bacteria from human dental plaque.

Samples of human dental plaque were examined for the presence of methanogenic bacteria. Of 54 samples from 36 patients, 20 yielded H2/CO2-using methanogenic enrichment cultures. All methanogen-positive samples were from patients with some degree of periodontal disease. The predominant populations in the enrichments had morphologies characteristic of Methanobrevibacter spp. In six enrichments derived from three patients, the common methanogen was antigenically similar to Methanobrevibacter smithii. The same was true for the three methanogenic isolates obtained in axenic culture from a fourth patient. The six enrichments and two of the three isolates were antigenically closer to strain ALI than to PS. Two of the enrichments also had subpopulations with weak antigenic similarity to Methanosphaera stadtmanae. The data indicate that methanogens in the oral cavity of humans are antigenically close to those found in the intestinal tract.     

Development of a fecal occult blood test using a monoclonal antibody to haptoglobin

Abstract

Monoclonal antibodies (mAbs) were produced to human haptoglobin by immunising with fecal extracts from patients with colon cancer. An enzyme-linked immunosorbent assay was developed with one of the mAbs (FE14.1), and its ability to diagnose colorectal carcinoma evaluated. Patients with colorectal cancer were positive (43/46 = 93.5%) compared to normal individuals (4/211 = 1.9%). The assay has a specificity 93.5% and sensitivity 98.1% and has several advantages over current fecal occult blood tests. The test is potentially useful for bowel cancer diagnosis and to quantitate the level of haptoglobin in other body fluids such as urine and in effusions.     

中国结肠癌病人中有甲烷短杆菌的证明

A fecal specimen from a Chinese patient (85-year-old man) suffering from colonic cancer was examined for the presence of methane-producing bacteria. As a result, a Methanobrevibacter organism was isolated. Our isolate did not grow in the presence of bile salts, a result different from Methanobrevibacter from healthy Americans' feces by Miller et al.     

Stability of Methanobrevibacter smithii populations in the microbial flora excreted from the human large bowel

Total anaerobic bacteria and Methanobrevibacter smithii populations were enumerated in fecal specimens from two individuals over 10- and 13-month periods. The ratio of M. smithii to total anaerobic count varied between the individuals, but it was a relatively constant proportion of the large-bowel microbial flora within each individual. Neither a barium enema examination of one subject nor a radical change in the diet of the other had any long-term effect on the methanogen populations.     

Quantitation and diversity analysis of ruminal methanogenic populations in response to the antimethanogenic compound bromochloromethane

Methyl coenzyme-M reductase A (mcrA) clone libraries were generated from microbial DNA extracted from the rumen of cattle fed a roughage diet with and without supplementation of the antimethanogenic compound bromochloromethane. Bromochloromethane reduced total methane emissions by c. 30%, with a resultant increase in propionate and branched chain fatty acids. The mcrA clone libraries revealed that Methanobrevibacter spp. were the dominant species identified. A decrease in the incidence of Methanobrevibacter spp. from the clone library generated from bromochloromethane treatment was observed. In addition, a more diverse methanogenic population with representatives from Methanococcales, Methanomicrobiales and Methanosacinales orders was observed for the bromochloromethane library. Sequence data generated from these libraries aided in the design of an mcrA-targeted quantitative PCR (qPCR) assay. The reduction in methane production by bromochloromethane was associated with an average decrease of 34% in the number of methanogenic Archaea when monitored with this qPCR assay. Dissociation curve analysis of mcrA amplicons showed a clear difference in melting temperatures for Methanobrevibacter spp. (80-82 degrees C) and all other methanongens (84-86 degrees C). A decrease in the intensity of the Methanobrevibacter spp. specific peak and an increase for the other peak in the bromochloromethane-treated animals corresponded with the changes within the clone libraries.     

Stability of Methanobrevibacter smithii Populations in the Microbial Flora Excreted from the Human Large Bowel

Total anaerobic bacteria and Methanobrevibacter smithii populations were enumerated in fecal specimens from two individuals over 10- and 13-month periods. The ratio of M. smithii to total anaerobic count varied between the individuals, but it was a relatively constant proportion of the large-bowel microbial flora within each individual. Neither a barium enema examination of one subject nor a radical change in the diet of the other had any long-term effect on the methanogen populations.     

Association between fecal methanogen species with methane production and grazed forage intake of beef heifers classified for residual feed intake under drylot conditions

Reduction in greenhouse gas emission from beef production is essential to the survival of the beef industry from environmental and social-economic perspectives. There are different systems available to measure methane from animals, but they are expensive, not easily accessible, and not suitable for large-scale methane measurements on the farm. Therefore exploring indicator traits, which are easy to measure, cost-effective, and suitable for large-scale measurement, are recommended. The objectives of this study were to examine the diversity of fecal methanogen profile among efficient and inefficient beef heifers on pasture and investigate methanogen profile as a possible proxy to predict methane emission in beef cattle consuming a forage diet. Forty pregnant (1st trimester) heifers previously classified for postweaning residual feed intake adjusted for off-test back fat (RFI_fat; 20 high and 20 low) were included in this study. To determine individual pasture grazing intake, heifers were dosed with 1 kg of C₃₂ labeled pellets once per day from Day 0 to Day 12, and fecal samples were collected twice daily from Day 8 to Day 15. Fecal samples from Days 8, 10, and 12 were analyzed for their methanogen profile. Animals were monitored individually for methane and carbon dioxide production using a GreenFeed Emissions Monitoring system. Total methanogen population and methanogenic community diversity of fecal samples were not different (P > 0.1) between low and high RFI_fat groups, as measured by quantitative PCR and α- and β-diversity indices. However, both groups had a different methanogen profile; the relative abundance of Methanobrevibacter wolinii and relatives were higher (P < 0.002), while that of Methanosphaera species ISO3-F5 was lower (P < 0.01) in low RFI_fat cattle compared to the high RFI_fat group. We also demonstrated that fecal methanogen profiles may be a useful proxy in predicting daily methane and carbon dioxide emissions with an adjusted R² of 0.53 and 0.33, respectively, for low RFI_fat heifers and 0.46 and 0.57, respectively, for the high RFI_fat group.