实验性大鼠溃疡性结肠炎菌群失调的诊断及复方树舌的治疗观察

目的探讨对溃疡性结肠炎厌氧菌菌群失调简便检查方法,寻找有效治疗溃疡性结肠炎的中药合剂。方法用冰乙酸诱发大鼠结肠炎模型,用复方树舌中药治疗,在治疗期间分别检测每组大鼠厌氧菌代谢产物、挥发性脂肪酸的含量、了解肠厌氧菌群改变,一般切片行HE染色,观察病理变化。结果（1）模型组大鼠挥发性脂肪酸明显低于正常组（P〈0．05）;pH从第2天起升高明显高于正常对照组（P〈0．05）,各治疗组与自然恢复组比较差异有显著性（P〈0．05）。（2）自然恢复组与各用药组间的炎症评分比较P〈0．01,各治疗组间比较,树舌加丽珠肠乐组组织损伤评分小（P〈0．05）。结论（1）测定厌氧菌的代谢产物挥发性脂肪酸含量,即可对肠内厌氧菌菌群失调做出判断。（2）实验证明,复方树舌中药可作为益生元调节肠道菌群失调及黏膜的修复,对溃疡性结肠炎疗效显著。     

活性污泥产酸发酵研究进展

有机物的厌氧生物处理一般经过三个阶段:水解阶段、产酸发酵阶段和产甲烷阶段;研究证明,产酸相不同发酵类型的形成对产甲烷相乃至整个工艺的稳定运行具有至关重要的作用,此外,污泥厌氧消化过程所产生的大量的挥发性脂肪酸(VFAs),如乙酸、丙酸、丁酸及戊酸等,还可作为化工原料用于发酵工业生产各种高附加值产品.近年来,产酸发酵受到越来越多的关注,该文主要对污泥产酸阶段的产酸发酵类型、产酸发酵细菌的生态学、产酸过程的影响因素和生态因子以及产酸发酵的液相末端产物VFAs的测定方法进行了论述.     

Simultaneous determination of volatile and non-volatile acidic fermentation products of anaerobes by capillary gas chromatography

A method previously used for the analysis of organic acids in silage has been applied to the detection and quantification of acidic fermentation products (C₁ to C₆ volatile fatty acids, lactic and succinic acid) of rumen bacteria and anaerobic fungi grown in pure culture. The acids were converted to tertiary butyldimethylsilyl derivatives prior to separation on a 30 m DB1 capillary gas chromatographic column. The quantitative recoveries of formic and succinic acids were found to be comparable to the recoveries of other acids reported in the original study. The quantitative recovery of lactic acid was found to be dependent on storage of the samples at ambient temperature for at least 24 h following derivatization. The simultaneous determination of a wide range of volatile and non-volatile acidic products is an important feature of this method.     

Identification and enumeration of oleic acid and linoleic acid hydrating bacteria in the rumen of sheep and cows

The diversity and population densities of facultative anaerobic bacteria with the capacity to hydrate oleic acid and linoleic acid in the rumen of sheep and dairy cows were determined. The screening of representative colonies, from rumen fluid plated aerobically on a range of agar media, revealed that sheep rumen fluid contained hydration-positive strains of Streptococcus, Staphylococcus, Enterococcus, Lactobacillus and Pediococcus, whereas cow rumen fluid contained hydration-positive strains of Streptococcus, Lactobacillus and Staphylococcus. Mean counts of facultative anaerobic bacteria in sheep and cattle rumen were log10 7.29 and log10 6.40, respectively, and were independent of diet. Approximately 56% of facultative anaerobic bacteria were able to hydrate oleic and/or linoleic acid in anaerobic broth culture. For both sheep and cows, the most numerous hydration-positive isolates were strains of Strep. bovis. The results, which are the first to show that pediococci have the capacity to hydrate unsaturated fatty acids, suggest that lactic acid bacteria are the major unsaturated fatty acid hydrating bacteria in the rumen.     

Comparison of digestive microflora between feedlot cattle with and without infection by<Emphasis Type="Italic">Cryptosporidium andersoni</Emphasis>

The influence of cryptosporidial abomasitis on digestive anaerobic microflora in feedlot cattle with spontaneous Cryptosporidium andersoni colonization of abomasum was shown. Significant differences were found after the cultivation of abomasal content. Scopulariopsis brevicaulis was detected in damaged areas of infected abomasum. PCR analysis of ruminal fluid showed no differences between the two animal groups regarding qualitative composition of anaerobic and facultative anaerobic rumen microflora. The concentration of volatile fatty acids (acetate, propionate, butyrate) and ammonia in the rumen content showed that examined metabolic parameters were within normal limits except for ammonia content, which was higher in infected (291 mg/kg) than in healthy animals (203 mg/kg).     

Isolation and characterization of a Klebsiella oxytoca strain for simultaneous azo-dye anaerobic reduction and bio-hydrogen production

A facultative anaerobic bacteria strain GS-4-08, isolated from an anaerobic sequence batch reactor for synthetic dye wastewater treatment, was investigated for azo-dye decolorization. This bacterium was identified as a member of Klebsiella oxytoca based on Gram staining, morphology characterization and 16S rRNA gene analysis. It exhibited a good capacity of simultaneous decolorization and hydrogen production in the presence of electron donor. The hydrogen production was less affected even at a high Methyl Orange (MO) concentration of 0.5 mM, indicating a superior tolerability of this strain to MO. This efficient bio-hydrogen production from electron donor can not only avoid bacterial inhibition due to accumulation of volatile fatty acids during MO decolorization, but also can recover considerable energy from dye wastewater.     

Investigation of the accumulation of aromatic compounds during biogas production from kitchen waste

This paper presents laboratory scale studies on the anaerobic degradation of kitchen waste, with a high protein and fat content, using a quasi-continuous co-digestion process. The increased accumulation of non-degraded intermediates as an indication of process imbalances was examined in experiments where the substrate load was gradually increased. In addition to the critical rise of known toxic metabolites like ammonia, hydrogen sulphide or volatile fatty acids, aromatic acids accumulated with increasing substrate loading. These metabolites could be identified as intermediates from the anaerobe degradation of the aromatic amino acids phenylalanine, tyrosine and tryptophan. In most experiments the important finding was the early detection of aromatics, especially phenylacetic acid, even before the monitoring of volatile fatty acid concentrations gave an indication of a process imbalance. This demonstrates the potential use aromatic acids as indicators for an upcoming process failure.     

Anaerobic degradation of dehydrodiisoeugenol by rumen bacteria

The degradation of dehydrodiisoeugenol (DDIE) by cow rumen bacteria was studied under strictly anaerobic conditions. After two days of cultivation, about 23% of DDIE (1.2 mM) was degraded to volatile fatty acids (VFA) such as acetic acid, propionic acid and butyric acid. The aromatic intermediates were vanillic acid, 5-methylvanillin and 3-methyl-4-hydroxybenzaldehyde, which suggested that the coumaran ring in DDIE was cleaved during degradation. These results indicate that the rumen anaerobes can degrade this lignin-related dimer to monoaromatic compounds and VFA.     

Digestion of epithelial tissue of the rumen wall by adherent bacteria in infused and conventionally fed sheep.

Comparisons were made, by light and electron microscopy, of the rumen epithelium of sheep fed conventionally and fed by infusion of volatile fatty acids and buffer into the rumen and casein into the abomasum. Similar bacterial colonization of the epithelium was observed in each case. The mitotic index of epithelial cells in infused sheep was high, as it was in barley-fed animals, while the mitotic index of cells from animals receiving roughage was low. The bacterial flora appeared to be actively digesting the epithelial cells. The fate of sloughed epithelial cells in the rumen fluid of sheep fed by infusion was also studied. The sloughed cells were rapidly digested, probably by their attached flora of facultatively anaerobic, highly proteolytic bacteria, leaving abundant highly keratinized remnants in rumen fluid. The importance of epithelial cell turnover and of proteolysis by partially facultative bacteria in the rumen is discussed.     

An evaluation of potential hydrogen sulfide adsorbents for the protection of palladium catalyst in anaerobic culture systems

Hydrogen sulfide is produced by many anaerobic bacteria and can irreversibly damage the palladium catalyst used for oxygen removal in anaerobic jars and cabinets. The present study used direct measurements of oxygen concentration to quantify catalyst activity following exposure to H₂S and volatile fatty acids in the presence of eight potential H₂S adsorbents. Most adsorbents were unsatisfactory, but two compounds not tested previously afforded full protection against the effects of H₂S alone and provided protection in the presence of volatile fatty acids. The investigation demonstrated the importance both of selecting an adsorbent suitable for use in anaerobic conditions and of heating anaerobic jar catalysts in order to maintain activity.     

小鼠盲肠内容物中正常菌群的分离和定量

本文报道了采用厌氧培养技术,从小鼠盲肠内容物中分离到6株严格厌氧和兼性厌氧菌。鉴定为拟杆菌、乳酸杆菌、双歧杆菌、难辨梭菌、粪链球菌和大肠扦菌。它们在小鼠盲肠内容物的正常菌群中占优势,含菌量与国外文献中报告的相似。     

Characteristics of the methane fermentation of waste of animal husbandry complexes with respect to the biomass of microorganisms and volatile fatty acids

The content of microbial biomass and the concentration of volatile fatty acids were comparatively studied in the tanks where the waste products of three stock farms were subjected to methane fermentation. The biomass content was shown to vary from 19 to 30% of the dry matter weight and the concentration of volatile fatty acids from 0 to 4.5 g per litre. The low concentrations of acetic and propionic acids together with the high biomass content were indicative of an active balanced microbial association. The parameters can be used to assess the operation of methane fermentation tanks.     

Quantitative gas chromatography of Bacteroides species under different growth conditions

From 56 strains of strictly anaerobic gram-negative rods isolated from stool and purulent lesions the fermentation products in the presence and absence of hemin were determined by quantitative gas-solid chromatography, using a simple and more rapid chromatographic procedure. With hemin the fermentation products were propionic, acetic, lactic and succinic acid. Without hemin no or little succinic acid was formed and the main products were lactic and acetic acid. In both groups the distribution of subspecies was determined and the production of fatty acids measured quantitatively.Fourteen strains of the lesion group showed a higher metabolic activity, resulting in an increased total acid production caused by an excessive production of acetic and lactic acid. This characteristic is probably a virulence factor in these strains.All strains were protoporphyrin- and oxgall-dependent. It is postulated that these substances are used for the production of cytochromes which permits the formation of succinic acid by a fumarate reductase resulting in an increased growth rate and growth yield.     

Inhibitory effect of medium-chain-length fatty acids on synthesis of polyhydroxyalkanoates from volatile fatty acids by Ralstonia eutropha

Medium-chain-length fatty acids, such as nonanoic (9:0) and octanoic (8:0) acids, are more toxic to Ralstonia eutropha than volatile fatty acids such as acetic, propionic and butyric acids. Nonanoic acid was degraded to acetic and propionic acids via -oxidation by Ralstonia eutropha for cell growth and synthesis of polyhydroxyalkanoates (PHAs). In a mixture of the fatty acids, utilization of nonanoic acid was depressed by acetic and propionic acids, and vice versa. The PHA accumulation from the volatile fatty acids was decreased from 53% (w/w) of dry cell mass to 23% due to the nonanoic acid. Similar phenomena were also observed with octanoic acid and its metabolic intermediates, acetic and butyric acids.     

Stratified mixed-culture biofilm model for anaerobic digestion

Development of a novel two-layer anaerobic biofilm model is based on substrate utilization kinetics and mass transport. The model is applied to steady-state conditions for a fixed-film anaerobic reactor. The microbial film is considered to consist of two distinct biofilm layers, one adjacent to the second, with an acidogenic bacteria biofilm forming the outer layer and a methanogenic film the inner one. The model assumes that sugars are only metabolized by the first layer and converted into volatile fatty acids (VFA), while fatty acids are taken up only by the inner layer. The model is able to predict both substrate flux net uptake and methane production for steady-state conditions. The results of modeling agree with methane production experimental data published elsewhere. Further, the model shows why layered fixed-film reactors can withstand high and inhibitory concentrations of volatile fatty acids as well as severe overloading without failure.     

Effect of nisin on two cultures of rumen ciliates

The effect of nisin (in the form of Nisaplin) was determined using two species of rumen ciliate protozoa in vitro, on their co-culture bacterial population, and volatile fatty acid concentration. Nisaplin did not affect the in vitro growth of Entodinium caudatum at concentrations of 50-400 mg/L during short-term treatment (5 d). Long-term application (30 d) of Nisaplin (100 mg/L) significantly decreased growth of the Epidinium ecaudatum forma caudatum et ecaudatum but not growth of E. caudatum. Nisaplin moderately supported the growth of E. caudatum after omission of wheat gluten (source of amino acids for protozoan growth). An inhibition of Gram-positive facultative anaerobic bacterial population in the protozoan cultures (lactobacilli, enterococci, staphylococci and amylolytic streptococci) was observed during long-term Nisaplin treatment. The concentration of volatile fatty acids significantly increased during the long-term Nisaplin treatment of both cultures. The propionate concentration in the mixture of volatile fatty acids was nearly twice higher on the account of the decreased concentration (from 74 to 63%) of acetate.     

Rates of fermentative digestion in the howler monkey, Alouatta palliata (primates: ceboidea)

1. Caecal material of wild howler monkeys was analyzed by gas chromatography for evidence of fermentation activity and rates of production and absorption of volatile fatty acids. 2. Results showed a high rate of production of acetic acid and lesser production of propionic, butyric and isobutyric acids. The VFA content of the blood was increase in passage through the caecal vascular system. 3. We estimate that howler monkeys may obtain as much as 31% of their required daily energy from fermentation end products. 4. Energy rich fatty acids may be of particular importance to howlers when they are living on diets high in leaves, which have high cell wall contents and low contents of nonstructural carbohydrates.     

Starch utilization by the human large intestinal microflora

High levels (2-565 units/g) of amylase activity were observed in human faeces. Over 92% of amylase activity in faeces obtained from healthy persons was extracellular, whereas only about 9% of activity was associated with particulate material and washed cells. Bacterial cell-bound amylases were considerably more efficient in breaking down starch, however, than were the soluble enzymes which occurred in cell-free faecal supernatant fluids. Cell population densities of anaerobic starch-hydrolysing bacteria in the stools of ten persons ranged from 1.1 X 10(10) to 3.3 X 10(12)/g of faeces. Identification of 120 starch-hydrolysing colonies isolated from the stools of six subjects showed that the predominant amylolytic bacteria belonged to the genera Bifidobacterium, Bacteroides, Fusobacterium and Butyrivibrio. Mixed populations of gut bacteria rapidly fermented starch with the production of volatile fatty acids and organic acids. Lactate was observed to be a major, though transient intermediate during starch fermentation by these cultures. Approximately 60% of starch utilized was converted to volatile fatty acids, which in the human colon would be potentially available for absorption.     

Starch utilization by the human large intestinal microflora

High levels (2–565 units/g) of amylase activity were observed in human faeces. Over 92% of amylase activity in faeces obtained from healthy persons was extracellular, whereas only about 9% of activity was associated with particulate material and washed cells. Bacterial cell-bound amylases were considerably more efficient in breaking down starch, however, than were the soluble enzymes which occurred in cell-free faecal supernatant fluids. Cell population densities of anaerobic starch-hydrolysing bacteria in the stools of ten persons ranged from 1.1 × 10¹⁰ to 3.3 × 10¹²/g of faeces. Identification of 120 starch-hydrolysing colonies isolated from the stools of six subjects showed that the predominant amylolytic bacteria belonged to the genera Bifidobacterium, Bacteroides, Fusobacterium and Butyrivibrio. Mixed populations of gut bacteria rapidly fermented starch with the production of volatile fatty acids and organic acids. Lactate was observed to be a major, though transient intermediate during starch fermentation by these cultures. Approximately 60% of starch utilized was converted to volatile fatty acids, which in the human colon would be potentially available for absorption.     

Gas chromatographic detection of anaerobic bacteria from environment.

A rapid method of detection of anaerobic bacteria in environment using gas chromatograph is described. Metabolically produced volatile and non-volatile fatty acid by the anaerobic bacteria are detected gas-chromatographically. Using this technique anaerobic bacteria are detected from soil, air, laboratory and operation theatre environments and drinking water samples. In the polluted drinking water apart from drug resistant E. coli, Clostridium difficile is isolated indicating faecal pollution of drinking water from cases of antibiotic associated pseudomembraneous colitis. The method has great significance in detection of anaerobic bacteria in environment especially in the management of war wounds.