Anerobic Bacteria Research Articles

Autonomous energy systems, bio-gas plants

Anerobic fermentation of organic matter — a process in the absence of atmospheric air — generates a mixture of gases: methane and carbon dioxide. The anerobic bacteria decompose the organic matter into sludge and methane, a gaseous fuel with a good calorific value. A number of organic wastes are suited to this method of methane generation: animal refuse such as cow dung, municipal and sewage wastes, vegetable wastes, human wastes and algae. Out of all these, for many a developing country with large population of cattle, cattle dung holds high promise. In this paper, I shall concentrate on the methane fuel economy based on cattle dung.

Antimicrobial therapy of experimental intraabdominal sepsis.

Septic complications of colonic perforation involve miltiple bacteria derived from the intestinal flora. This type of mixed intraabdominal infection was produced experimentally by insertion of a standardized inoculum of rat colonic contents into the peritoneal cavity of male Wistar rats. The respective roles of coliforms and anerobic bacteria were then studied by use of selective antimicrobial therapy (with gentamicin and clindamycin). Untreated rats had a two-stage disease. Initally, there was an acute peritonitis associated with a 37% mortality rate; all animals that survived developed indolent intraabdominal abscesses. Treatment with gentamicin reduced the acute mortality rate to 4%, but 98% of the survivors had abscesses. Clindamycin acute mortalherapy was associated with a 35% mortality rate, but the incidence of intraabdominal abscess was only 5%. A combination of gentamicin and clindamycin yielded the salutary effects of each agent--7% mortality and 6% incidence of abscesses. These studies, in concert with bacteriological findings, suggest that coliforms caused early mortality while anaerobes were primarily responsible for the late complication of intraabdominal abscess formation.

Evolution of the prokaryotes

A scheme for the evolution of the prokaryotes is proposed. This is based on the assumptions that (1) the main course of early prokaryotic evolution after the development of an effective genetic apparatus was determined by the problem of generating metabolically usable energy under anerobic conditions and (2) that each of the major metabolic types of anerobic bacteria existing today is mainly composed of surviving representatives of the corresponding stages in prokaryote evolution. In this paper, known species of bacteria are arranged in a postulated phylogenetic sequence which begins with the simplest anerobes and progresses through a series of relatively small, discrete steps to the photosynthetic bacteria and the blue-green algae. The latter, by introducing substantial amounts of oxygen into the biosphere, radically altered the possibilities available for energy production, and led to a second major era of prokaryote evolution with the appearance of the aerobes. Some of the implications of this hypothesis for the phylogeny and taxonomy of the prokaryotes are discussed.

Identification of ceramide phosphorylethanolamine and ceramide phosphorylglycerol in the lipids of an anaerobic bacterium

Nearly half the phospholipids isolated from the anerobic bacterium Bacteroides melaninogenicus are phosphosphingolipids. The two major phosphosphingolipids have been characterized as ceramide phosphorylethanolamine and ceramide phosphorylglycerol. The long-chain bases of these phosphosphingolipids appear to have branched and normal saturated carbon chains of 17, 18, and 19 atoms; the phosphate is at the 1-position of the long-chain base. The composition of the amide-linked fatty acids of the phosphosphingolipids differs from that of the ester-linked fatty acids of the diacylphosphoglycerides in having a higher percentage of 14:0, 17:0, and 18:0 acids as well as containing nearly all the monoenoic fatty acids found in the bacterial lipids. The finding of phosphosphingolipids in bacteria is exceedingly rare and to our knowledge ceramide phosphorylglycerol has not been previously found in nature.

An improved method for determining celluloytic activity in anerobic bacteria.

SUMMARYAn improved method for determining cellulolytic activity in anaerobic bacteria is described in which the disintegration of a filter paper strip denotes activity. By inoculating the paper‐containing media from dilutions of material such as rumen contents estimates of the numbers of cellulolytic bacteria in the original material may be made. The method can also be used for determining cellulolytic activity of pure cultures. Morphology and other properties of the bacteria may be determined.

数種食品防腐剤の嫌気性菌に対する発育抑制効果と培地成分の影響

Effect of components of culture media for anerobic bacteria on the sensitivity of various Clostridia to chlortetracycline (CTC), tylosin (TI), furyl-furamide (FF) and nitrofurazone (NFS) have been examined. Test organisms were 9 strains of stock Clostridia including Clostridium perfringens, Cl. tetani, Cl. histolyticum, Cl. sporogenes and 3 types of Cl. botulinum, in addition, 10 strains of Clostridia isolated from fish sausages and fish hams, species names of which were shown in Table 2. Culture media employed in this experiment were the thioglycollate medium (TGC), the brain heart infusion medium containing 0.1% agar (BHI+A), and the BHI medium covered with sterile liquid paraffin (BHI+P) which were adjusted to pH 7. Minimal inhibitory concentrations (MIC) of test drugs were determined in the respective medium containing binary dilution series of each drug after being incubated at 37°C for 24, 48, 72 and 96 hours. Results obtained may be summarized as follows: 1. As to CTC, no significant difference in MIC values was observed according to the kind of culture medium, while these values varied markedly by the length of incubation period which might be due to the instability of CTC in the culture media (Figs. 1 and 2). 2. In the case of TI, much higher MIC values were noted in the TGC medium than those obtained in both of the BHI media in spite of the stability of the drug in the TGC medium, whereas no appreciable change could be seen depending upon the length of incubation period (Table 1). 3. In the TGC medium, FF gave highest MIC values (Table 1), in addition, these values increased greatly according as the incubation period increased. These phenomena might be due to rapid inactivation of the drug by the action of reducing agents in the medium (Fig. 2). To the contrary, MIC values were fairly low when determined in either BHI-A or BHI-P medium, moreover, almost no appreciable change was noted by the length of incubation period (Tables 1 and 2). 4. Growth inhibitory effect of NFS to various Clostridia was found to be the lowest among 4 drugs so far tested, especially almost no activity was observed in the TGC medium which might be explained by the rapid destruction of the drug in the medium during incubation (Fig. 2).

CONTINUOUS CULTURE OF SOME ANEROBIC AND FACULTATIVELY ANAEROBIC RUMEN BACTERIA.

SUMMARY: Strains of Streptococcus bovis, Selenomonas ruminantium, and an anaerobic lipolytic bacterium (5s) have been grown under carbohydrate-limiting conditions in continuous culture for long periods. With S. ruminantium and bacterium 5s the fermentation products varied with growth rate. Yield of organism in continuous culture of all three bacteria showed a maximum at a particular growth rate. The yield of S. ruminantium was much higher in continuous culture at optimum growth rate than in batch culture, and was also higher than can be explained on present concepts of the energy from fermentation available for growth. The various results are discussed in the light of results obtained with other bacteria and the conditions obtaining in the rumen.

Microbiological Studies of Bruised Tissuesa,b,c

SUMMARYMicrobiological examination of poultry bruises revealed that 61.0–74.2% of the tissues examined harbored both aerobic and anerobic bacteria. These organisms were found, in experimentally inflicted bruises, to increase in number at the early stages of healing (1–2 days), followed by a rapid decrease to the level of the controls within 4–6 days. Age of bruise, environmental conditions (sanitation of batteries, temperature, and moisture), severity of the bruise, and hemoglobin and its degradation'products were found to be among factors affecting the microbial content and their growth in bruised tissue.A total of 86 predominant organisms were isolated from experimentally inflicted bruises; of these, 47 were Gram‐positive cocci, 19 Gram‐negative rods, 11 yeasts, 7 Gram‐positive rods, and 2 Gram‐negative cocci. Thirty‐six percent of the Gram‐positive cocci were found to belong to the genus Staphylococcus. Forty‐eight percent of the Staphylococcus cultures were identified as S. aureus, and the others were S. epidermis. Fecal material and poultry feed were shown to be the source of the predominant organisms.The skin of the injured tissue may be a possible portal of entry of these microorganisms. Bruising increased the permeability of the tissue as determined by dye penetration and the extent of microbial invasion.

Redoxpotentialmessungen in bestrahlten Lebensmitteln

An investigation was made to determine if redox potential measurements could replace the more complicated bacteria counting in the evaluation of microorgainisms surviving the irradiation of food. Fish and meat were sealed in plastic bags in a vacuum and irradiated. The samples were stored at plus or minus 1 deg C and redox potential measurements and bacteria enumerations were made until the food spoiled. In the non-irradiated food the redox potentials decreased as the aerobic bacteria were multiplying and then started increasing with development of the anerobic bacteria. In the irradiated samples the redox potential increases during the time the bacteria development is inhibited. The velocity of the appearance of the positive potential is temperature dependent. The results indicate that redox potential measurements can replace bacteria counting in food research. (J.S.R.)

Sulfur isotopes and the origin of sandstone-type uranium deposits [Colorado Plateau and Wyoming

An isotopic study of sulfide minerals associated with sandstone-type uranium deposits of the Colorado Plateau and Wyoming indicates S 32 /S 34 ratios of these 57 samples varying between 21.93 to 23.32. The majority, however, exhibit ratios that are highly enriched in the lighter isotope compared to the ratio of primordial sulfur that is assumed to be similar in ratio to meteoritic troilites, which vary in ratio from 22.18 to 22.24.The samples are predominantly pyrite and marcasite, but chalcopyrite, covellite, and bornite are included, even though the sulfide mineral species appears to have no relationship to the specific ratio obtained. There is, furthermore, no indication of a difference between ratios obtained from sulfides collected within uranium ore zones in comparison to ratios of sulfides occurring in either adjacent or distant barren uranium ground. The formations (Triassic to Eocene) from which the samples were collected have no obvious correlation with the ratios, nor does the presence or absence of lignitic, woody, or other carbonaceous matter show any correlation with the ratios.The relatively broad spread of these high ratio values, especially of those samples collected from one deposit, is very suggestive of hydrogen sulfide derived from anerobic bacteria. It is suggested that sulfate waters (possibly both connate and meteoric in origin) in Mesozoic sediments of the Colorado Plateau area were reduced by anerobic bacteria to hydrogen sulfide when these waters encountered carbonaceous-rich zones that provided an environment and energy source for the bacteria. The hydrogen sulfide may have remained where formed or may have migrated to locales barren of carbonaceous matter, but most likely did both.At a later date, about 60 to 75 million years ago, ore solutions moving through these more porous and permeable channels encountered the very effective reducing agent of hydrogen sulfide which brought about the concentration of uranium through precipitation of the soluble uranyl ions to relatively insoluble UO 2 . At the same time iron (and in some cases copper) sulfate was precipitated as relatively insoluble sulfides.

ACTION OF CERTAIN SULFONAMIDES AND OF THIOUREA UPON THE FUNCTION OF THE THYROID GLAND OF THE RAT1

GOITER changes in the thyroid gland have been observed to follow a variety of experimental conditions. A century ago iodine was used in the treatment of thyroid enlargement and it has become well established that hyperplastic goiters ensue when the dietary iodine is reduced below a certain level. Although iOdine deficiency is said to be the commonest cause of thyroid hyperplasia in the human being and in experimental animals, a great many agents have been seen to cause a similar thyroid effect in such animals as rodents, ungulates, birds,fishand man. Reference to the extensive literature on this subject shows that the following agents have, under the conditions of the several experiments, induced thyroid enlargement: high protein diets (1–5), diets containing a large proportion of liver (4–7), fat (5), soybeans (8), or calcium salts (9–11), polluted water, bacterial cultures, fecal filtrates and filtrates from cultures of anerobic bacteria (12), diets composed largely of cabbage or related greens (13,14),...

Oxygen Requirement of Pathogenic Bacteria Under Starving Conditions

Conclusions and SummaryUnder partial starvation some aerobic and facultative anerobic bacteria, yeasts, and fungi grow only in a fine, dense layer below the surface of the shake-cultures where the relation between nutrient-content and oxygen is an optimum. Under increasing starvation bacteria become increasingly sensitive against oxygen. Oxygen causes a bacteriostatic effect, the rate of which is in relation to the nutrient content of the medium. The less the medium contains of carbon compounds which may act as oxygen acceptor, the more inhibitory is the action of oxygen on the organisms. Variation in temperature below and above the optimal temperature and exposure to light increases the sensibility against oxygen.