Composition Of Bacterial Flora Research Articles

Genetic and environmental factors in colorectal carcinogenesis.

The molecular genetic mechanisms of colorectal cancer are among the best understood of any common cancer. Recent research has identified mutated tumor suppressor genes and oncogenes as normal tissue progresses from benign to malignant, and the novel mismatch repair genes involved in a specific form of hereditary colorectal cancer as well as a significant percentage of sporadic cases. This information has led to a better understanding of the inheritance of large bowel cancer, as well as a model of tumorigenesis which proposes a multistep process as colonic epithelial cells progress from their normal state through successive stages of adenoma to malignancy. Exogenous factors such as fiber and fat are important modifiers of inherited risk. Dietary factors may influence the carcinogenic process by modifying intestinal transit time, altering the flow and recycling of bile, or changing the intestinal bacterial flora composition. A number of studies have also suggested the modulation of risk in both hereditary syndromes and sporadic cases with certain micronutrients or medications like nonsteroidal anti-inflammatories.

The relationship between clinical symptoms and anaerobic bacteria from infected root canals

The purpose of this study was to investigate the correlation between the composition of bacterial flora from infected root canals and clinical symptoms. The materials evaluated consisted of 28 teeth from 25 patients with apical periodontitis. Eubacterium were found to be significantly related to acute or chronic clinical symptoms and Peptococcus, Peptostreptococcus, and Porphyromonas gingivalis to subacute clinical symptoms. We suggested that Peptococcus, Peptostreptococcus, Eubacterium, Porphyromonas, and Bacteroides were significantly related to percussion pain; Porphyromonas and Bacteroides were significantly related to odor in the infected root canals. Many Bacteroides were isolated from most of the infected root canals.

Identification and population dynamics of bacteria in leaf spots of soybean

The qualitative and quantitative composition of bacterial flora occurring inside the leaf spots of field grown soybeans was studied during the growing seasons (June to October) of 1989 and 1990. As a rule these leaf spots (necrotic lesions with chlorotic haloes) were caused by Pseudomonas syringae pv. glycinea. This pathogenic bacterium was predominantly found during the whole season in the symptomatic leaf tissue. Other species, mainly Erwinia herbicola, were also found in the same habitat. The population sizes of P. s. pv. glycinea increased from the beginning of symptom occurrence until July, stabilized until September, and then decreased a little. In general, the size of saprophytic populations was orders of magnitude lower than that of the pathogenic populations. The number of different bacterial genera per sample increased up to four genera per leaf spot by the end of the season. No significant influence of the occurring saprophytes on the population dynamics of the pathogen in planta could be observed.

水陸両生魚，ムツゴロウとトビハゼの消化管内細菌フローラ

Bacterial flora and viable counts in the gills and the digestive tracts (stomach and intestine) of mudskipper fishes Boleophthalmus pectinirostris and Periophthalmus cantonensis and in mud of a mud flat were studied to discuss the primary factors which control the composition of bacterial flora in the digestive tracts.The flora was composed principally of Vibrio, coryneforms and others in the mud and the gills, and of Vibrio or coryneforms in the digestive tracts. The composition of flora in the stomach was similar to that in the intestine for P. cantonensis but not for B. pectinirostris. The counts in the stomach were much lower than that in the intestine for B. pectinirostris but could not recognize obvious difference between the two for P. cantonensis. The counts in the intestines of both the fishes were much higher in aerobic incubation than in anaerobic incubation and a large part of bacteria counted in aerobic incubation was Vibrio. The maximum count was in 100% sea water medium in the mud but in 50% sea water medium in the intestines, and a large part of bacteria accounted in both the samples was Vibrio. The counts in the digestive tracts were lower in autumn than in spring and summer in case of B. pectinirostris but almost equal for all seasons in case of P.cantonensis.From these facts it was presummed that the flora of the digestive tracts is influenced by bacteria from the mud, differing from the stage of progress of the stomach and from wintering season in the fishes, being controlled by salt concentration and oxygen tention of sea water to be supplied through “water-drinking” for osmoregulation.

Composition of bacterial flora in sliced vacuum packed Bologna‐type sausage as influenced by nitrite

SummaryThe influence of the addition of 0, 100 and 200 p.p.m. nitrite to sliced vacuum packed Bologna‐type sausage was studied at 2, 5, 10 and 20°C. An increasing inhibition of growth of Brochothrix thermosphacta, Enterobacterinceae and MoraxellalMoraxella‐like organisms was found with increasing nitrite concen‐ tration andlor decreasing temperature. The gram positive cocci, the yeasts and lactic acid bacteria were only inhibited to a limited extent. Consequently the lactic acid bacteria became more dominant in vacuum packed cooked meat product with added nitrite. The gram negative bacteria often constitute the major flora in packages produced without nitrite, and may proliferate at higher temperatures even in samples produced with nitrite.

Rhizoplane microorganisms of rice seedlings as examined by scanning electron microscopy

Abstract Rhizoplane microorganisms of water cultured rice seedlings inoculated with soil microorganisms were examined by scanning electron microscopy and optical microscopy. Composition of the bacterial flora on the rhizoplane were also studied. Microorganisms on rhizoplane were limited only in bacteria consisting mostly of rods. They were distributed in every region except the root tip zone. Bacterial aggregations were common at ruptured sites of epidermal cells and cell junctions. They were also dispersed and adhered on mucigel, bare epidermal surface, and root hairs. The area covered with bacteria in the whole root surface was, however, relatively small (1–9%, average 4.6%). Some rhizoplane bacteria were seen to invade into the roots through ruptured sites on epidermis and mucigel. The composition of bacterial flora on rhizoplane was much simpler than that in the paddy soil from which soil inocula were prepared. Pseudomonas and Bacillus occupied about 60 and 40 per cent of the total found in rhizoplane...

カキの細菌フローラ

The present study was undertaken to analyse the bacterial flora of culture-oysters and of the silt accumulating on their shells. All the oysters were taken from two different areas of Hiroshima Bay during July and November, 1973, and the following January. Enumeration and isolation of bacteria were conducted with a smear plate method using 50 percent seawater agar medium. Identification was based chiefly on the scheme of SHEWAN et al. The generic composition of bacterial flora of the oysters differed from that of the marine water; that is, a very large portion of the isolates from the oysters consisted of genus Vibrio with no seasonal variation observed, while in the marine water pseudomonads were predominant. The ratio of psychrophilic vibrios to mesophilic ones, all isolated from the oyster samples, varied with the three seasons. The bacterial flora of the silt was also composed mainly of vibrios, which were usually the same kind as those of the oysters. The generic composition of the flora of commercial shucked oysters collected from some department stores in Tokyo in December, 1974, and the following January, was very similar to that of the culture-oysters.