Methods for Detecting Carbohydrate Fermentation by Gram-Negative Nonsporeforming Anaerobes

Fermentation of carbohydrates by gram-negative anaerobes may be detected rapidly and conveniently in small volumes of thioglycollate broth, incubated in Gas-Pak jars.     

Gram-Negative Anaerobes in the Intestinal Flora of Pigs

A differential count of the gram-negative, anaerobic, non sporeforming bacteria in different segments of the pig intestinal tract was performed in 2 groups of pigs. Seventy-seven strains were identified, belonging to 6 groups: Sphaerophorus necrophorus, anhemolytic Sphaerophorus spp., Bacteroides (Eggerthella) spp., Fusobactenum spp., Veillonella/Acidaminococcus spp., and Peptostreptococcus elsdenii. The characters of these groups are described, and quantitative data on their occurrence in a group of normal porkers and a group of pigs with experimental swine dysentery are given.     

Fermentative Degradation of Polyethylene Glycol by a Strictly Anaerobic, Gram-Negative, Nonsporeforming Bacterium, Pelobacter venetianus sp. nov

[This corrects the article on p. 1913 in vol. 45.].     

Methods for Detecting Food-borne Enteroviruses

A method previously reported for detecting virus in a model system composed of cottage cheese contaminated with coxsackievirus type A9 has been adapted to detecting selected strains of enteroviruses in a variety of foods. Bentonite is omitted and serum is added for extracting virus from low-protein foods. Samples of foods, usually 25 g, must contain at least 3 to 4 plaque-forming units for a 50% probability of detecting virus. Sensitivity in detecting echovirus type 6 was lower than that for the other viruses used. After extraction from potato salad, poliovirus type 2 was completely reactivated if it had been neutralized with coproantibody, but it was only partially reactivated if neutralized with hyperimmune rabbit serum.     

Extracellular Formation of Alanine by Anaerobes

The possibility of extracellular formation of amino acids by anaerobes was investigated. In general, anaerobes were able to produce 20 to 50 mg of alanine per dl of medium extracellularly. Clostridium saccharoperbutylacetonicum, the anaerobic bacterium for acetone-butanol fermentation, accumulated 100 mg of alanine per dl of medium containing 5 g of glucose, 1 g of ammonium acetate, 0.1 g of potassium dihydrogen phosphate, 0.04 g of magnesium sulfate, 0.001 g of ferrous sulfate, 1 μg of biotin, 0.1 g of yeast extract and 1 g of calcium carbonate in tap water.

Relationships between alanine formation and solvent yields or sporulation were investigated. Spore formation was not active in the medium for alanine formation and yield of acetone increased in this medium.     

Extracellular Formation of O-Butylhomoserine by Anaerobes

Clostridium BB–264, Cl. acetobutyricum 314–48, Cl. kaneboi, Cl. saccharoperbutylacetonicum and other two strains of Cl isolated recently produced an unidentified ninhydrin-positive compound in medium containing 5 % glucose, 1 % ammonium acetate, 0.1 % potassium dihydrogen phosphate, 0.04 % magnesium sulfate, 0.001 % ferrous sulfate, 0.1 % yeast extract, 10 μg/liter of biotin and 1 % calcium carbonate.

This ninhydrin-positive compound was eluted with solvent composed of butanol: acetic acid: water (4: 1: 2) by chromatography on cellulose powder column. It was crystallized from ethanol and then identified as an amino acid, O-butylhomoserine (Abbrev. as O-BHSer). Yield of this amino acid increased by adding homoserine or butanol to the medium. The increase was also recognized with addition of glycine, lysine, serine, threonine or valine. The formation of this amino acid was repressed by adding methionine to the medium.

Gas pressure to the culture is one of the important factors that make the amino acid formation by anaerobes possible.     

细胞程序性死亡的判定方法

胞程序性死亡有别于一般意义上的死亡──坏死,所以对其判定显得格外重要．国内外目前常从细胞形态、细胞膜完整性、DNA及某些重要生化指标等方面进行判定．     

微卫星DNA检测方法的研究

在检测牙鲆的微卫星变异时,对聚丙烯酰胺凝胶的种类、浓度及其银染方法进行了优化.实验总结了一套适用于微卫星检测的方法.该方法具有灵敏度高、凝胶透明度高、对环境污染小、条带清晰和染色时间短等特点,能显著提高检测分辨率,具有广泛的推广价值.     

Production of Resting Forms by the Gram-Negative Chemolithoautotrophic Bacteria Thioalkalivibrio versutusand Thioalkalimicrobium aerophilum

The haloalkaliphilic chemolithoautotrophic gram-negative bacteria Thioalkalivibrio versutus, strain AL2, and Thioalkalimicrobium aerophilum, strain AL3, were shown to possess the capacity to produce resting forms, namely cystlike refractile cells (CRC), whose production was controlled by the level of the d₁ extracellular factors exhibiting the function of anabiosis autoinducers. The conditions were elucidated that promote the formation of CRC in the developmental cycles of the cultures studied, in condensed cell suspensions undergoing autolysis, and under the action of exogenously introduced chemical analogues of anabiosis autoinducers (alkylhydroxybenzenes). The peculiarities of the fine structure of the resting cells obtained were studied. Distinctions were revealed (with respect to viability and thermotolerance) between the CRC formed under different conditions. The relationship between the growth strategy and survival strategy of extremophilic bacteria is discussed taking into account the effect of the d₁ autoregulatory factors. A new model of CRC formation is proposed: CRC production in the life cycle of bacteria developing under conditions of increased concentration of anabiosis autoinducers.     

New Method for Detecting Bacteriocin Production

Bacteriocin production can be easily detected by using both sides of the agar contained in a standard petri dish.     

Simple Method for Culturing Anaerobes

A simple, effective method is needed for growing obligate anaerobes in the clinical laboratory. This report describes a pre-reduced anaerobic bottle that can be taken to the bedside for direct inoculation, provides a flat agar surface for evaluation of number and morphology of colonies, and can be incubated in conventional bacteriological incubators. Each anaerobic culture set consisted of two bottles containing brain heart infusion agar and CO₂. Gentamicin sulfate (50 μg/ml) was added to one of these to inhibit facultative enteric bacilli. Comparison of the anaerobic bottles with an identical aerobic bottle which was also routinely inoculated permitted early identification of anaerobic colonies. Representative species of most anaerobic genera of proven pathogenicity for man have been isolated from this system during 10 months of routine use.     

Recent Advances in Indole Alkaloid Production by Catharanthus roseus (Periwinkle)

Considerable progress has been accomplished in cell culturetechniques for production of indole alkaloids fromCatharanthusroseus. This paper reviews the advances made in this area. Keyeffects of nutrients, environmental effects, stress-inducingcompounds and strain selection techniques on the productionof alkaloids are summarized. Cultivation methods such as suspensioncultures, immobilization, and a novel biofilm configurationare compared. Economic considerations in the large scale productionof secondary metabolites are covered. Indole alkaloids, cellculture techniques, Catharanthus roseus. Key words: Indole alkaloids, cell culture techniques, Catharanthus roseus     

Apparatus for Metabolic Studies with Anaerobes

An apparatus is described which allows metabolic experiments with obligate anaerobic bacteria to be performed with minimal disturbance of the E(h) of the culture.     

Improved Culture Flask for Obligate Anaerobes

An improved flask system for the growth of extremely oxygen-sensitive bacteria in liquid culture is described. The improvement described utilizes an all-glass, neoprene-stoppered flask designed for growth of 50- to 1,000-ml cultures of bacteria with continuous gassing.