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PubMed1999

Organotin compounds and their interactions with microorganisms.

Organotin compounds are ubiquitous in the environment. The general order of toxicity to microorganisms increases with the number and chain length of organic groups bonded to the tin atom. Tetraorganotins and inorganic tin have little toxicity. Because of their lipophilicity, organotins are regarded as membrane active. There is evidence that the site of action of organotins may be both at the cytoplasmic membrane and intracellular level. Consequently, it is not known whether cell surface adsorption or accumulation within the cell, or both is a prerequisite for toxicity. Biosorption studies on a fungus, cyanobacteria, and microalgae indicates that cell surface binding alone occurred in these organisms, while studies on the effects of TBT (tributyltin) on certain microbial enzymes indicated that in some bacteria TBT can interact with cytosolic enzymes. Microorganism-organotin interactions are influenced by environmental conditions. In aquatic systems, both pH and salinity can determine organotin speciation and therefore reactivity. These environmental factors may also alter selectivity for resistant microorganisms in polluted systems. Tin-resistant microorganisms have been identified, and resistance can be either plasmid or chromosomally mediated. In one TBT-resistant organism, an Altermonas sp., an efflux system was suggested as the resistance mechanism. Biotransformation of organotin compounds by debutylation or methylation has been observed. These reactions may influence the toxicity, mobility, and environmental fate of organotin compounds.

Bacteria↗

PubMedDate not supplied

[The effect of biostimulants and fungicides on the growth parameters of natural associations of soil microorganisms].

Biostimulants ivin and emistym take positive effect on the growth characteristics of natural association of soil microorganisms: they increase the specific growth rate, the number of generations, decrease the lag-phase and duration of redoubling the number of microorganisms. Presence of fungicides in the medium inhibits the growth of microorganisms. Under combined use of biostimulants and fungicides one cannot reveal the negative effect of fungicides on the natural associations of microorganisms, however the stimulating action of growth-regulating substances decreases.

Culture Media↗

PubMedDate not supplied

Effects of solutions used in infants' oral hygiene on biofilms and oral microorganisms.

The purpose of this work was to evaluate the effects of oral hygiene solutions used for infants on biofilms formed in vitro from infants' saliva and dental plaque: ATCC reference strains A. viscosus; C. albicans; L. casei; S. mitis; S. mutans; S. oralis; S. sanguis; S. sobrinus and clinically isolated microorganisms (saliva) C. albicans, S. mitis, S. mutans, S. oralis, S. sanguis and S. sobrinus. After exposure of the oral biofilms to H2O2 diluted 1/4 to 1/16; and NaF 0.02 percent, concentrated and diluted 1/2, for 1 and 3 minutes, the viable count of microorganisms, compared to the controls was significantly reduced (p < 0.05). They also showed a significant antimicrobial effect for all the microorganisms evaluated, when compared to the control (p < 0.05). Exposure to sodium bicarbonate solution and a camomile solution, for 1 and 3 minutes, was not significantly lethal to oral biofilms nor to any microorganism evaluated, regardless of whether they were concentrated or diluted. We do not recommend the use of H2O2 but suggest using the camomile solution and NaF 0.02 percent in a rational manner for cleaning the infant's mouth.

Biofilms↗

PubMed2001

[Comparative study of chromatography-mass spectrography of microorganism's chemical markers in blood and intestinal mucosa bioptats].

Fatty acids, that are microorganism's markers in blood and jejunum's, ileum's, and large intestine's bioptats of the patients with irritable bowel syndrome were investigated with gas chromatography. Markers of Cl. perfringens, Cl. difficile, Enterococcus, Streptomyces, Enterobacterial, Klebsiella, E. coli, Peptostreptococcus, Candida Albicans, genus of Streptococcus, of Staphylococcus, of Fusobacterium sp and others microorganisms were revealed. Settling of intestinal mucosa was the same in jejunum, ileum and large intestine (0.5-1.3) x 10(10) cells/gr. and was approximately the same as microorganism's concentration in feces (1.8 x 10(11) cells/gr). Correlation of blood and bioptats markers was demonstrated in the most patients. The possibility to use specific fatty blood acids as microorganisms markers in preliminary diagnosis of mucosa microflora changes is discussed.

Bacterial Infections↗

PubMed2001

Exposure to airborne microorganisms and endotoxin in herb processing plants.

Microbiological air sampling was performed in two herb processing plants located in eastern Poland. Air samples for determination of the levels of bacteria, fungi, dust and endotoxin were collected at 14 sites during cleaning, cutting, grinding, sieving, sorting and packing of 11 kinds of herbs (nettle, caraway, birch, celandine, marjoram, mint, peppermint, sage, St. John's wort, calamus, yarrow), used for production of medications, cosmetics and spices. It was found that processing of herbs was associated with a very high pollution of the air with bacteria, fungi, dust and endotoxin. The numbers of microorganisms (bacteria and fungi) in the air of herb processing plants ranged within 40.6-627.4 x 10(3) cfu/m3 (mean +/- S.D = 231.4 +/- 181.0 x 10(3) cfu/m3). The greatest concentrations were noted at the initial stages of production cycle, during cleaning, cutting and grinding of herbs. The numbers of airborne microorganisms were also significantly (p<0.0001) related to the kind of processed herb, being the greatest at processing marjoram, nettle, yarrow and mint. The values of the respirable fraction of airborne microflora in the examined facilities varied within a fairly wide range and were between 14.7-67.7%. The dominant microorganisms in the air of herb processing plants were mesophilic bacteria, among which endospore-forming bacilli (Bacillus spp.) and actinomycetes of the species Streptomyces albus were most numerous. Among Gram-negative bacteria, the most common was endotoxin-producing species Alcaligenes faecalis. Altogether, 37 species or genera of bacteria and 23 species or genera of fungi were identified in the air of herb processing plants, of these, 11 and 10 species or genera respectively were reported as having allergenic and/or immunotoxic properties. The concentrations of dust and bacterial endotoxin in the air of herb processing plants were large with extremely high levels at some sampling sites. The concentrations of airborne dust ranged within 3.2-946.0 mg/m3 (median 18.1 mg/m3), exceeding at 13 out of 14 sampling sites the Polish OEL value of 4 mg/m3. The concentrations of airborne endotoxin ranged within 0.2-2681.0 microg/m3 (median 16.0 microg/m3), exceeding at all sampling sites the suggested OEL value of 0.1 microg/m3. In conclusion, the workers of herb processing plants could be exposed to large concentrations of airborne microorganisms, dust and endotoxin posing a risk of work-related respiratory disease.

Air Microbiology↗

PubMedDate not supplied

[Fine structure of mummified cells of microorganisms formed under exposure to a chemical analog of anabiosis autoinducer].

Under the influence of alkyl hydroxybenzene (C6-AHB) added to cell suspensions at a concentration of (1-5) x 10(-3) M, the cells of Saccharomyces cerevisiae, Micrococcus luteus, and Thioalkalivibrio versutus underwent dramatic changes in the ultrastructural organization of cell membranes, cytoplasm, and inclusions. In yeast suspension, the first changes were observed after 15 min in the structure of slit-like invaginations in the cytoplasmic membrane (CM): they were shortened and thickened. In the subsequent 30 to 60 min, CM ruptures were formed in the regions devoid of intramembrane protein particles and in the slit-like invaginations. After 24 h, complete disintegration of the intracellular membrane structures and conglomeration of the ribosomal part of the cytoplasm occurred. Similar changes were observed on the exposure of gram-positive and gram-negative bacteria to AHB. However, the cell wall in all the microorganisms studied was not destroyed, and in Micrococcus luteus it was even thickened. These mummified forms were preserved as morphologically intact but nonviable cells for more than three years of observations. By their ultrastructural characteristics, these mummified forms of microorganisms were similar to the fossilized microorganisms discovered by us in fibrous kerite. The concept of micromummies was formulated. AHB are supposed to play an important role in the process of fossilization of microorganisms in nature.

Adaptation, Physiological↗

PubMedDate not supplied

Pediatric osteomyelitis: III. anaerobic microorganisms.

Primary osteomyelitis consequent to obligate anaerobic microorganisms represents an infrequently encountered type of infection in pediatric patients. Unlike osteomyelitis caused by more common microorganisms such as Staphylococcus, children with osseous lesions due to anaerobic microorganisms are frequently minimally symptomatic and rarely present the classic signs of fulminant osteomyelitis. Radiographically, the lesions may mimic malignant osseous tumors. Fastidious microbiologic analysis of the material obtained at surgery is necessary to isolate obligate anaerobes. Basic treatment, comprising surgical drainage and appropriate antimicrobial agents, does not differ from that for osteomyelitis caused by aerobic or by facultative anaerobic microorganisms.

Adolescent↗

PubMed2002

Measurement of microorganisms with PHA production capability in activated sludge and its implication in activated sludge model no. 3.

In Activated Sludge Model No.3 (ASM3), it is hypothesized that all heterotrophic microorganisms (X(H)) can store substrate. However, in reality, both microorganisms with and without substrate storage capability (X(H/STO) and X(H/S), respectively) could exist. If the ratio of X(H/STO) in activated sludge is influenced by operational and environmental conditions, kSTO (storage rate constant of heterotrophic microorganisms which is defined in ASM3) may not be a universal parameter and can change from case to case. In this study, polyhydroxyalkanoate (PHA) is assumed as the principal storage product, and the ratio of microorganisms with PHA production capability (X(H/PHA)) in various activated sludges was estimated by the dual staining of Nile Blue A (NB) and DAPI. It was shown that the ratio of X(H/PHA) in sludge varied among different municipal and laboratory activated sludges.

Environmental Monitoring↗

PubMed2002

[Interaction between microorganisms and heavy metals and its application].

Interactions between microorganisms and heavy metals were expatriated in many ways. Because of their resistance and detoxification to heavy metals, microorganisms are able to leach, absorb and transform heavy metals, which has been actively applied to extract heavy metals from low-rate ore in mine exploitation. Although heavy metals are toxic to microorganisms population and harmful to its processes, some special microorganisms have been applied to the treatment of industrial waste materials and the remediation of soils polluted by heavy metals. The application of microbiological biomass and activity to evaluating the pollution situation and ecological risk of heavy metals in environment media is also significant.

Bacteria↗

PubMed2002

[Molecular-ecological technology of microorganisms and its application to research on environmental pollution].

Nucleicacid probe detection, PCR technique using primer, DNA sequential analysis, and electrophoresis separation and display were summarized and the application of these techniques to research on environmental pollution and future developing directions were discussed. It was pointed out that molecular-ecological technology of microorganisms are playing an important role in studying on relationships between microorganisms and contaminated environment. There are some important advances such as genetic adaptation and evolutionary mechanisms of microorganisms in contaminated environment, the positioning of pollutant-degrading genes of microorganisms and the construction of microbiological engineering bacteria, thus promoting the development of molecular ecology for bioremediation of contaminated environment.

Bacteria↗

PubMed2002

Comparative investigation of airborne culturable microorganisms in sewage treatment plants.

The present study investigated emissions and emmissions of airborne microorganisms (mesophilic bacteria, Escherichia coli, molds, Aspergillus fumigatus, thermophilic actinomycetes/bacilli) in sewage treatment plants. For the aerobiological investigations three sewage treatment facilities with an activated-sludge process, capacities between 2000 and 28,000 PE and different cleaning steps were selected. The measurements of microorganism emission were conducted in the area of the intake (screen), in the area of biological treatment (activated sludge tank) and at a distance of 10 m from the activated sludge tanks. In order to determine the emmission, additional measurements were conducted leeward of the plant at a distance of 200 m. Samples were taken using four parallel six-stage Andersen 1 AFCM volumetric samplers. In the area of the intake counts for bacteria were 7.4 x 10(2) CFU/m3 (median), for thermophilic actinomycetes 1.8 x 10(1) CFU/m3, for thermophilic bacilli 7.1 x 10(1) CFU/m3, for molds 2.4 x 10(3) CFU/m3 and for Aspergillus fumigatus 1.8 x 10(1) CFU/m3. Only isolated airborne coliform recoveries, i.e. E. coli, were detected. In the area of the activated sludge tank, in the adjoining area (10 m) and in the vicinity of the plants (200 m), the counts for all microorganism groups investigated corresponded to natural conditions. The results show that the counts of culturable aerogenic microorganisms in and in the immediate surrounding of the sewage plants investigated are low. Although the possibility of an infection through inhalation cannot be ruled out, the direct contact with sewage is much more critical.

Air Microbiology↗

PubMedDate not supplied

[Fructose-bisphosphatase of microorganisms].

Data from modern scientific literature concerning general characteristics of fructose-bisphosphatase--the key enzyme of microorganisms gluconeogenesis pathway have been analyzed in the survey. The conditions of fructose-bisphosphatase functioning in the cell--activation and repression, have been described. Regulation of prokaryotes enzyme activity by fructose-1.6-bisphosphate, fructose-2.6-bisphosphate, phosphoenol pyruvate, metal cation, etc., is discussed. Absolute dependence of fructose-bisphosphatase activity on cations of bivalent metals (Mg2+, Mn2+) and AMP is shown. Special attention was given to the functioning and characteristics of the enzyme in prokaryotes and eukaryotes: their similarity and differences. Data about the basic enzyme of gluconeogenesis pathway in Gram-positive and Gram-negative microorganisms, conditions of its functioning in autotrophs and heterotrophs have been generalized for the first time. Genetical and molecular biological properties of fructose-bisphosphatase in microorganisms have been considered. At the same time, the fact is established that the above enzyme has not been investigated in numerous microorganisms.

Amino Acid Sequence↗

PubMed2002

[Bio-active substances derived from marine microorganisms].

Marine microorganisms, which are taxonomically diverse and genetically special, have powerful potential in producing novel bio-active substances. This article summarized research progress in this respect. The results showed that marine bacteria which are main marine microorganism flora can produce rich kinds of bio-active substances and that even though marine actinomycetes and marine fungi are not as many as marine bacteria in species and quantity, they should be paid no less attention about their bio-active substances. Besides, present research are limited to those marine microorganisms which are easily cultured. One of the future research trends will be focused on bio-active substances derived from non-culturable marine microorganisms.

Bacteria↗

PubMed2002

[Effect of spore-free anaerobic microorganisms of pancreatic tissue in experimental acute pancreatitis].

The simulation model of an acute pancreatitis (AP), using translocation of microorganisms from intestine to ductal system and pancreatic tissue, was created in experiment on dogs. Interrelationships between pancreatic tissue and anaerobic microorganism in an AP were studied, using electron microscopy. Possibility of the microorganisms migration to pancreas from ductal system in early stage of AP due to enhanced reproduction of anaerobic microorganisms in duodenum was established. It is impossible to exclude the possibility of their invasion via the lymph and the blood flow into destructively changed pancreatic tissue in late terms of the disease.

Animals↗

PubMed1998

[Studies on microbiological factor in colour change of mogao graffito's mural. II. Effect of microorganism on the pigment of imitative mural].

Throung the assay and analysis of the imitative mural after cultivated with microorganisms, it has been shown that microorganisms had a pronounced effect on the pigments of the mural: the pigments secreted by microorganisms changed the colour of the mural, and produced much oxalic acid salt, which damaged the formation of crystals of the pigment, moreover, the chemical combination valence of Pb3O4 had been changed due to the metabolic products of microorganisms, that may play an important role in the chemical change of Pb3O4.

Bacterial Physiological Phenomena↗

PubMed2003

[Advances in studies on genetically engineered microorganism ecology].

Genetically engineered microorganism ecology has been one of main research contents in microorganism molecular ecology. Along with the introduction of molecular marker and molecular biology, traditional microorganism ecology has been developed; therefore, it is possible to study the relationship between GEM and environment, environmental microorganism under molecular level. The GEM ecology has become a new and intersection borderline discipline, related to molecular biology, microbiology, ecology and so on. Moreover, it brought forward that the prosecution of the research on the transgenic organism ecology and the risk assessment, and the foundation of checking means and valuating standard that adapt to the situation of China could help to the development of GEM ecology in China.

Ecology↗

PubMedDate not supplied

[New method for the determination of anti-lactoferrin activity of microorganisms].

A new method for the determination of the antilactoferrin activity (ALfA) of microorganisms, based on the detection of lactoferrin by the enzyme immunoassay, is proposed. The new method widens the spectrum of microorganisms to be tested, makes it possible to detect lactoferrin inactivation by bacteria producing antagonistically active substances (muramidases, organic acids, hydrogen peroxide, etc.), increases the reliability of the determination of the ALfA antilactoferrin activity of microorganisms due to the increased accuracy of its quantitative characterization. Testing of the culture fluid for lactoferrin following the growth of microorganisms in a medium with this protein revealed the capacity to inactivate lactoferrin in bacteria (Escherichia coli, Salmonella sp.) and yeast-like fungi (Candida sp.), isolated from feces and clinical material, of persons with carrier states, dysbiotic disturbances and pyoinflammatory diseases.

Candida↗

PubMed1992

[Biotechnology using modified microorganisms].

Few microorganisms, as compare to their high diversity, are used for human needs. They can produce molecules of interest, process fermentation, protect crops, treat wastes or clean environment. Molecular technics and genetic engineering are new tools offer to geneticists which breed microorganisms for years. Using them, it is now possible, theoretically, to introduce any gene in any organism. Some examples are given concerning genetic modifications in yeasts and lactic acid bacteria to optimize agrofood processes and to improve nutritive and flavour characteristics of fermented products like bread, beer, wine, cheese, meat, vegetable juices... In spite of scientific and industrial interest of the new technologies, limiting factors can explain that genetically modified microorganisms are not routinely used in agrofood yet. First, risks assessment on human health and environment are still in debate, but their is a consensus, within the scientific community, to consider that new characteristics of improved microorganisms are more important than the technics used for their construction. Second, regulations turn out to impose constraints susceptible to discourage technological innovations. At least, the public perception about the new technologies appears, actually, as the major factor to limit their development.

Genetic Engineering↗