Choseki Furusaka

A new agar plate method for the quantitative study of sulfate-reducing bacteria in soil

Abstract Sulfate-reducing bacteria, widely distributed in natural environments, have a specific ability to reduce sulfate and to form hydrogen sulfide, which reacts with iron or/and manganese present in the environments and forms a black precipitate of iron or/and manganese sulfide. This specific reaction is useful for the simple and selective detection of sulfate-reducing bacteria in mixed bacterial populations as in soil.

The distribution of nitrifying bacteria in soil aggregates.

Abstract The special arrangement of soil particles composing aggregates is known to give some influences on nitrifying bacteria in soil. Greenwood (962) (1) showed that the activity of nitrifying bacteria in an aggregate is limited by the diffusion of oxygen into it through its pores. He pointed out the possibility of the co-existence of 2 zones of the entirely different characters in an aggregate, i. e., an aerobic zone, only in which nitrifying bacteria are able to be active, and an anaerobic zone. Neither he nor SEIFERT (1964) (2), who made a similar discussion to Greenwoods, however, made further examination in the distribution of nitrifying bacteria in an aggregate. Both of them assumed the distribution of nitrifying bacteria as homogenous in all parts of an aggregate.

Bacteriological studies on the mineralization of organic nitrogen in paddy soils: I. Effects of mechanical disruption of soils on ammonification and bacterial number

Abstract In this report we studied the effects of mechanical grinding of paddy soils on nitrogen mineralization and bacterial number when soils were incubated under a submerged condition after grinding. Nitrogen mineralization was increased by grinding soil samples as compared with those without grinding. The value of (Nd-Nu)/Nu, where Nd is the amount of ammonia-nitrogen formed by incubation of disrupted samples and Nu those of the undisrupted soils, was in good correlation with clay/humus ratio. Although significant difference was not observed between the number of aerobic bacteria with undisrupted and disrupted soil samples, higher anaerobic bacterial numbers were found with disrupted than with undisrupted ones. A significant correlation was also obtained between the amounts of nitrogen mineralization increased by the grinding of soil and the numbers of anaerobic bacteria.

Distribution of sulfate-reducing bacteria in paddy-field soil

Abstract The distribution of sulfate-reducing bacteria in a paddy-field soil was investigated by enumerating the viable number of the bacteria in minute loci. A small area having 20 mm or 40 mm square was divided into 100 sections; a small amount of soil was sampled form each section and the bacterial number was estimated by the anaerobic agar plate method. The distribution patterns of the bacteria were represented by distribution maps. The numbers of the bacteria in the sections showed distinct variations among the sections. The sections having large bacterial numbers showed high concentrations in some parts of an area. The aggregated distribution pattern was common in the soil, whether it was under drained or waterlogged condition, and indicates that there seem to be some centers of multiplication of sulfate-reducing bacteria in paddy-field soil.

STUDIES ON THE BACTERIA ISOLATED ANAEROBICALLY FROM PADDY FIELD SOIL : III. Production of Fatty Acids and Ammonia by Clostridium Species

Abstract The volatile fatty acids produced by the representative strains of clostridia isolated from paddy field soil were surveyed. All the strains, except Cl. tertium, utilized only amino acids as the sole source of energy for growth. All of them produced acetic and butyric acids, and some of them produced propionic acid in addition. Iso-valeric and iso-butyric acids were also produced, except by Cl. tertium. These results suggest that all the strains, except Cl. tertium, may carry out the STICKLAND reaction. The cells of each strain harvested from the culture in the VL medium were subjected to examination whether or not they carried out the STICKLAND reaction in the presence of leucine or glycine. All the strains, except Cl. tertium, catalyzed the STICKLAND reaction and some strains also metabolized leucine and glycine even when they were supplied singly.

Studies on glycine-percolated soil IV. Fractionation of bacteria in glycine-percolated soil in “two-layered sucrose solution system”

Abstract Bacteria in a soil crumb are thought to have at least two kinds of habitat (1). Bacteria living in “the outer-part”** of a soil crumb are directly exposed to influences of environmental conditions such as supply and exhaustion of nutrients or loss of moisture. Consequently, the number of the viable bacteria fluctuates dramatically with these changes. On the other hand, the bacteria in “the innerpart” of the soil crumb are influenced by environmental conditions to a lesser extent.

Comparative study of soil bacterial flora as influenced by the application of a pesticide, pentachlorophenol (PCP)

The effects of pentachlorophenol (PCP) applications on the taxonomic composition of bacterial microflora were studied in water-logged soil (WS) and in shake cultures of suspended soil (SS). PCP applications resulted in a predominancy of Gram-negative bacteria over Gram-positive species. Members of the Acinetobacter group were the most common in PCP-treated soil although a small portion of the flora were in the Pseudomonas-Alcaligenes group or belonged to the Enterobacteriaceae. Coryneform bacteria and species of the Bacillus were the dominant forms in untreated WS; however, WS cultures treated with PCP at recommended rates (2.67 gm/m2) evidenced species of Pseudomonas, Alcaligenes, Acinetobacter, and members of the Enterobacteriaceae as the predominant bacterial species. The dominance of Gram-negative bacteria in PCP-treated soil was evidenced for 3 months after application of the compound but was not evident after 17 months when PCP had dissipated. Gram-negative bacteria found in PCP-treated soil were highly tolerant of the phenol. In WS cultures coryneform bacteria were the most common although PCP tolerance was heterogenous in nature.

Studies on the bacteria isolated anaerobically from paddy field soil IV. Model experiments on the production of branched-chain fatty acids

Abstract Based on the fact that the clostridia isolated from paddy field soil were mostlyproteolytic and that they produced some branched-chain volatile fatty acids on peptone media, the occurrence and the substrates for the production of such acids in paddy soil were investigated. The results obtained are as follows: 1) It was revealed that two branched-chain volatile fatty acids, iso-valeric and iso-butyric acids, were detected In fresh paddy field soil. 2) The paddy soil supplemented with peptone solution produced significant amounts of branched-chain volatile fatty acids-iso-butyric and iso-valeric acidsin addition to straight-chain volatile fatty acids-acetic, propionic, and butyric acids. When glucose was added instead of peptone, not branched-chain fatty and propionic acids were detected but only acetic and butyric acids. These facts indicate that the branched-chain fatty acids may originate from amino acids. 3) When a pair of amino acids, such as proline and leucine or proline-and valine, were sup...

Influence of organic matter on the distribution of sulfate-reducing bacteria in a paddy-field soil

Abstract It was reported in previous papers (1, 2) that suifate-reducing bacteria were not uniformly distributed throughout a paddy-field soil. They appeared to grow in small contiguous clumps scattered throughout the soil and this suggests the heterogeneous distribution of minute loci with different growth conditions for sulfate-reducmg bacteria in the soil; i.e., the scattering of organic matter, the association of other microorganisms, the availability of soil water and air, the oxidation-reduction potential and so on. In marine sediments, the distribution and activity of suifate-reducing bactena were reported to be influenced mainly by organic matter therein (3). In a paddy-field soil, we have often observed that organic matter, such as plant debns and rotted roots, was present in the center of the dark black soil mass. In the experiment desenbed m this paper, an attempt was made to elucidate the influence of organic matter on the distribution pattern of suifate-reducing bacteria in the soil.

EFFECT OF OXYGEN TENSION ON BACTERIAL NUMBER IN A SOIL SUSPENSION

Abstract Growth of three groups of bacteria, strict aerobic, facultative anaerobic and strict anaerobic ones, in soil suspensions when they were incubated under various oxygen tensions was surveyed. Compositional patterns of the three bacterial groups under various oxygen telisions were classified into three types. The first type, observed under higher oxygen tensions than 16 mmHg, is that strict aerobic bacteria dominated. The second type which occurred in the case of incubation under the oxygen tension of 1-2 mmHg, is that the number of aerobic bacteria became almost comparable to that of anaerobic bacteria. The third type, brought about by the incubation under strict anaerobic condition, is that only strict anaerobic bacteria dominated.