Mucoid strains of Escherichia coli, Acinetobacter calcoaceticus, and Erwinia stewartii were significantly more resistant to desiccation than corresponding isogenic nonmucoid mutants (survival rates of up to 35% in mucoid strains and between 0.7 and 5% in nonmucoid variants), even in colonies containing both cell types. Desiccation was found to bring about an induction of beta-galactosidase in Lon- strains of E. coli K-12 carrying transcriptional lac fusions in the capsule biosynthetic (cps) regulon. This induction was dependent on the transcriptional activators RcsA and RcsB. Induction was lower in cells carrying mutations in the membrane sensor protein RcsC.

Annual C inputs from plant production in terrestrial ecosystems only meet the maintenance energy requirements of soil microorganisms, allowing for little or no net annual increase in their biomass. Because microbial growth within soil is limited by C availability, we reasoned that plant production should, in part, control the biomass of soil microorganisms. We also reasoned that soil texture should further modify the influence of plant production on soil C availability because fine—textured soils typically support more microbial biomass than coarse—textured soils. To test these ideas, we quantified the relationship between aboveground net primary production (ANPP) and soil microbial biomass in late—successional ecosystems distributed along a continent—wide gradient in North America. We also measured labile pools of C and N within the soil because they represent potential substrate for microbial activity. Ecosystems ranged from a Douglas—fir forest in the western United States to the grasslands of the mid—continent to the hardwood forest in the eastern U.S. Estimates of ANPP obtained from the literature ranged from 82 to 1460 g°m— ²°yr— ¹. Microbial biomass C and N were estimated by the fumigation—incubation technique. Labile soil pools of C and N and first—order rate constants for microbial respiration and net N mineralization were estimated using a long—term (32 wk) laboratory incubation. Regression analyses were used to relate ANPP and soil texture with microbial biomass and labile soil C and N pools. Microbial biomass carbon ranged from 2 g/m² in the desert grassland to 134 g/m² in the tallgrass prairie; microbial N displayed a similar trend among ecosystems. Labile C pools, derived from a first—order rate equation, ranged from 115 g/m² in the desert grassland to 491 g/m² in the southern hardwood forest. First—order rate constants for microbial respiration (k) fell within a narrow range of values (0.180 to 0.357 wk— ¹), suggesting that labile C pools were chemically similar among this diverse set of ecosystems. Potential net N mineralization rates over the 32—wk incubation were linear in most ecosystems with first—order responses only in the alpine tundra, tallgrass prairie, and forests. Microbial biomass C displayed a positive, linear relationship with ANPP (r² = 0.51), but was not significantly related to soil texture. Labile C also was linearly related to ANPP (r² = 0.32) and to soil texture (r² = 0.33). Results indicate that microbial biomass and labile organic matter pools change predictably across broad gradients of ANPP, supporting the idea that microbial growth in soil is constrained by C availability.

The coconut palm is amenable to intensive crop combinations at most periods of its life and great possibilities exist for increasing the agricultural production through intensive cropping in coconut areas. Coconut palms are grown under diverse soil conditions ranging from littoral sands to clayey soils (Menon and Pandalai, 1960). In pure stand of coconuts at normal planting (7.5 x 7.5 m) density and management conditions, about 75% of the area is not being effectively utilised to the fullest extent by coconut roots (Kushwah et al. 1973). The intensive cropping system involving coconuts are essentially crop combinations which envisage the cultivation of other compatible crops in the interspaces between the palms. Depending upon the duration of additional crops, so grown, the system shall be considered as inter, mixed, multi‑storeyed or multispecies cropping. The crops chosen vary from tract to tract (Nelliat and Shama Bhat, 1979).

In order to estimate the effect of heavy metal pollution on soil microorganisms, field surveys were carried out in paddy fields, upland fields, and fallow paddy fields located in two areas with heavy metal pollution in Japan. There was no significant correlation between the viable counts of microorganisms and heavy metal content of the soils. In a polluted area, the D500 value of the fungi was higher in the fallow paddy field soils than in the paddy or upland field soils. These results suggest that the effects of heavy metal pollution on soil microorganisms vary depending on the land use

Kinetics of CO2 evolution from arable chernozem soils amended with glucose has been studied. Long-term application of mineral or organic fertilizer forms microbial community with the typical for every variant growth parameters. Fertilization with NPK for years leads to domination of K-strategist: slow growing microorganisms with ability to consume a substrate at the lowest concentrations. In the unfertilized soil a lesser part of microbial community is active, but is characterized by more pronounced r-strategist features. The microorganisms are able to the most rapid growth under unlimited conditions. There is no limitation of growth with mineral elements in chernozem constantly manured with organic. In this case the most pool of microorganisms capable of glucose mineralization is formed

This book brings together a number of comprehensive accounts of the mechanisms whereby microorganisms are able to degrade a wide variety of compounds. These compounds range from petroleum-derived materials, which continue to predominate in questions of environmental contamination and pollution, to the degradation of the major natural materials that microorganisms may encounter in all types of habitat. Both aerobic and anaerobic modes of attack are covered. The emphasis in all the chapters is upon the underlying biochemical pathways that microorganisms use: differences between bacteria, yeasts and moulds are highlighted whenever opportune and uses of microbial consortia for attack on the most recalcitrant molecules is also well-documented. Activity of microorganisms in the soil, groundwater and marine environments are all dealt with here. The book will be of value and interest to all whose work brings them into direct or even indirect contact with the results of microbial degradations. The consequences of microbial degradations may be beneficial as well as deleterious: an advantage with some compounds, a decided disadvantage with others. The basis by which microorganisms achieve these attacks then provides the vital knowledge that will accelerate the former and, hopefully, retard the latter. For the first time, the pathways of microbial degradations of all major classes of compounds are covered in a single volume. The diversity of microbial activities are clearly described and current advances in the applications of biochemistry, molecular biology, genetics, enzyme chemistry and engineering feature in almost every chapter.

The ratio in bacteria number between different groups of microorganisms plays a certain part in their interaction. Strains of Lactobacilli and starters for yoghurt as well as the test-microorganisms Proteus sp. and Listeria sp., was used in present investigation. It was established that it wasn't necessary for Lactobacilli to predominate in number to have antagonistic action

The microbial flora transferred to carcasses during slaughter is a reflection of the care taken on the slaughter floor and of the types and numbers of microorganisms acquired by the animal on the farm or during the period of transportation to the slaughter house. These microorganisms may include those able to cause illness in the consumer, or microorganisms responsible for spoilage of the product. Considerable progress has been made in reducing contamination at slaughter and thereby extending the shelf-life of meat. In contrast, international statistics still clearly show that meat and meat products are responsible for a major proportion of all foodborne infections. This latter aspect is not determined by the overall number of microorganisms present but by the bacterial composition of the. animal's gut flora at slaughter. Preventive quality assurance along the whole productions and processing line is therefore the only effective means of controlling the microbiological safely and quality of meat. This includes, hazard analysis techniques to identify critical control points and procedures for monitoring the microbiological status of both animals and carcasses since most of the critical points cannot be totally controlled. At early stages in the production line, colonisation of meat animals with pathogens should be prevented. Subsequently, good slaughter practices will ensure carcasses of good overall microbiological quality. This paper deals with microbiological monitoring systems that can be used at different stages of production and processing to control the microbiological quality of poultry and pig meat.

A percolation experiment was conducted using soil columns to analyze the sources of microorganisms and organic materials responsible for anaerobic CH4 oxidation in the subsoil of rice paddies. A glass column packed with plow layer soil and rice straw was connected to a column with sterilized or heated (550 degrees C, 12 h) subsoil. Leachate was periodically collected from the bottom of the subsoil and analyzed for the contents of CH4, ferrous iron, and carbon in the water soluble organic materials (TOC). Methane concentration in the leachate decreased by percolation into the subsoil. Sterilization and removal of organic materials from the subsoil did not affected appreciably the CH4 content in the leachate from the subsoil column. Sterilization of the subsoil enhanced the leaching of TOC and ferrous iron from the subsoil and production of ferrous iron in the subsoil. Removal of organic materials from the subsoil decreased ferrous iron production in the subsoil. These observations suggested that CH4 was oxidized in the subsoil by microorganisms which were leached from the plow layer soil. Methane-oxidizing microorganism(s) appeared to use organic materials which were also leached from the plow layer soil. Microorganisms and organic materials in the subsoil contributed to ferric iron reduction but not to CH4 oxidation