Effect of soil compaction on microbiological activity in the calcareous chernozem soil under sugar beet has been studied. It was found that the number and activity of microorganisms depends on the degree of soil compaction, kind of microorganisms and type enzymes. Soil compaction reduced the total number of aerobic bacteria and the number of ammonifiers, nitrifiers, actinomycetes, fungi, azotobacter, oligonitrophilous bacteria and cellulolytic microorganisms and increased the total number of anaerobic bacteria and denitrifiers. Also, soil compaction reduced the dehydrogenase, protease and urease activities of microorganisms.

The properties of microbial strains responsible for the rapid mineralization of the herbicide glyphosate in soil were investigated in soil-water mixtures supplemented with 10 mmol l(-1) active ingredient. Over 2 weeks degradation kinetics were linear, as expected in the case of non-growth-linked metabolization, and the rate of utilization was not enhanced following repeated treatment of the soil with increasing herbicide doses. The availability of exceeding phosphorus, nitrogen and carbon sources did not affect the rate of glyphosate utilization, that was maximal under conditions of neutral pH, high oxygen and low osmolarity. The screening of 1200 bacterial strains isolated on a rich medium in the absence of the herbicide failed to identify any strain able to cleave the glyphosate molecule. When antibiotics with different mode of action were added to the mixtures, while some inhibitors of protein synthesis exerted considerable effects, those that are active only against actively-proliferating cells were scarcely effective. An MPN analysis was performed to enumerate degrading microorganisms, but in no dilution the same extent of utilization measured in the original mixture could be found. Results suggest that at least the first steps in herbicide degradation could be accomplished by some microbial species unable to grow in vitro and form visible colonies on plates.

Numbers of various microorganisms (total number of microorganisms, numbers of ammonifiers, azotobacters, fungi, actinomycetes and other free nitrogen-fixing bacteria) have been followed in a black meadow soil planted to eight bean varieties. Immediately before planting, been seeds have been inoculated with a microbiological preparation (NS-Nitragin for beans). Numbers of the studied microorganisms have decreased in the course of vegetation in relation to the situation immediately before planting, with the exception of the total number of bacteria which, at the end of the vegetation, reached the original sitiation immediately before the planting. On average for all varieties, the numbers of azotobacters and ammonifiers were lowest at the stage of flowering. The obtained results have shown that root exudates and plowed under corn stalks affected the numbers of the microorganisms under study.

The influence of zeolite and bentonite on physical-chemical and microbiological parameters of pig slurry was studied. After 28 days of contact of pig slurry either with zeolite or with bentonite, the plate counts of psychrophilic and mesophilic microorganisms decreased by 3 orders of magnitude in comparison with the control. The efficiency of removal of psychrophilic and mesophilic microorganisms was 98.9 % and 100 %, respectively. Coliform microorganisms were not detected after 14 days of the treatment of slurry either with zeolite or with bentonite. No fecal coliform microorganisms were detected in bentonite-treated slurry after 7 days of contact and in zeolite-treated slurry after 14 days of contact. During the experiment a decrease in the concentration of ammonium nitrogen (N-NH+4), total nitrogen (Nt), total phosphorus (Pt) and chemical oxygen demand (COD) was observed.

Microorganisms colonizing the leaf sheaths of rice plants placed in a water-logged paddy field were studied using a scanning electron microscope. Decomposition was faster on the adaxial side than on the abaxial side of the leaf sheaths. The veins and trichomes were highly resistant to microbial decomposition throughout the waterlogged period of rice growth. The decomposition and disintegration of leaf sheaths markedly progressed from the third month (from July) after the placement in the paddy field. Microbial colonization was gradual in the first month after the placement of leaf sheaths in the field. One of the common first colonizers had a terminal endospore (Clostridium dissolvens-like microorganisms). Microbial colonization proceeded actively in the second month, and microbiota became diversified. Microbial colonization on the adaxial surface was more than that on the abaxial surface. Respective microorganisms colonized the surfaces separately from each others in this period. They grew mainly on the thin membrane that covered the epidermal layer. Microbial colonies spread all over the abaxial and adaxial surfaces, and there was no significant difference in the degree of colonization between the abaxial surface and the adaxial surface in the third month (in July). Although separate colonization of the respective microorganisms was common, the co-existence of different microorganisms within a colony was also observed. The thin membrane that covered the epidermal layer and the epidermis seemed to be the main substrate during this period. Co-existence of different microorganisms was a common occurrence in colony formation, and organic debris and remaining tissues of leaf sheaths were assumed to b6 the major substrates in August. These findings on microbial colonization were well correlated with the findings on the degree of decomposition

Microbiological studies were carried out on 634 milk specimens collected aseptically from mammary gland quarters that had reacted positively to quick diagnostic tests for mastitis (Bernburg or Manu-Test, Alpha-Laval Agri). Causative microorganisms were isolated from 69.72% of the samples. Most of the microorganisms are Gram-positive staphylococci, mainly S. aureus (58,37%) and streptococci (11,54%) and also corynobacteriae (3,85%), Ps. aeroginosa (2,71%) and others (4,75%). In 18,78% of the cases the subclinical mastitis was caused by mixed infections in which two microorganisms participate, mostly staphylococci and streptococci. Str. agalactiae has not been isolated so far in the country as a causative agent of mastitis in buffaloes.

International audience | Microorganisms able to grow at low temperature, that is near 0°C, have been known for over 100 years in natural and manmade cold environments such as marine and continental waters, soils and foods. Until recently, the molecular basis of cold adaptation was poorly investigated. Most studies have been pragmatic, dealing with food microorganisms (mainly bacteria) with the aim of preventing their growth. During the late 1960s and 1970s, many papers were published on the ecology as well as the physiology of cold-adapted microorganisms. Most are now seldom referred to or even considered by those working in the field of cold adaptation. Except for lipid composition, more fundamental research was restricted by the lack of tools for such investigations. Moreover, most studies dealt with the heat sensitivity of cold-adapted microorganisms, which, although being of interest, is a consequence not the cause of cold adaptation. Others considered the effect of chilling on mesophiles such as Escherichia coli, which is mesophilic and cannot grow at 0°C, and cannot be considered as a universal model for organisms growing at low temperatures.