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At least 1,099 records · Page 61Linked to original sources
PubMedDate not supplied

[The resistance of soil microorganisms to soil pollution by heavy metals].

Microbial communities of grey podzolized soil of Left-Bank Ukraine are characterized by high potential resistance to pollution with heavy metals: above 40% of organotrophic microorganisms are capable to resist to pollution with a mixture of heavy metals (Cu2+, Cd2+, Pb2+, Zn2+) in a dose of 20 MPC of each metal. Relative amount of resistant microorganisms in polluted soil increases up to 93%. White zeolites and biohumus are promising for reclamation of soils polluted with heavy metals. They decrease toxic effect of heavy metals on soil microflora and promote development of microflora resistant to pollution.

Colony Count, Microbial↗
PubMed1999

[Examining interaction of phages with microorganisms by fluorometry and electro-orientation spectroscopy].

Bacterial sensitivity to different various phages was examined by electro-orientation spectroscopy, fluorometry, and electron microscopy. The strains of Pseudomonas aeruginosa, Staphylococcus aureus, Yersinia pestis, Mycobacterium smegmatis, and Xanthomonas campestris were used. The fluorescence intensity of a membranotropic agent in the ANS-cell-phage system was shown to depend on the interaction of a bacterial virus and a microorganism. Fluorometric data correlated with electro-orientation spectroscopic findings. An analysis of the low-frequency site makes it possible to determine phage adsorption on the bacterial surface. The changes in electro-orientation effects at high frequencies suggest that there are barrier dysfunctions in the external membranes and that there is cellular phage reproductions. Whether fluorometry and electro-orientation spectroscopy can be further used for rapid identification of microorganisms by using phages is discussed.

Bacteriophages↗
PubMed1999

[Detection of airborne cultivatable microorganisms from compost sites--emissions and imissions].

The statement presented here gives an overview and assessment of the procedures and concepts currently used for the collection and determination of airborne, culturable microorganisms at sources of emission within composting plants and in their near vicinity. The paper focuses on "classical" methods, which involve cultivation as an intermediate step for the determination of viable, airborne microorganisms. The theoretical and practical requirements on such methods are discussed. Results and experiences from recent investigations are described.

Air Microbiology↗
PubMed1999

[Determining the emission of microorganisms from biofilters and emission concentrations at the site of composting areas].

In order to assess source emissions and dispersal of airborne culturable microorganisms from composting plants, measurements at three composting plants have been carried out. The downwind concentrations of dispersed microorganisms differed greatly, depending on the type of plant design. At 200 metres downwind from the totally enclosed composting plant, levels of spore concentrations of thermotolerant fungi and Aspergillus fumigatus, which may be regarded as characteristic for composting operations, were not above the magnitude of background concentrations. In contrast, spore concentrations in excess of the background level occurred within 500 metres of the partly open plant. Moreover, the ranges of airborne concentrations at similar distances from the enclosed plant were much smaller relative to the partly open plant. Measurement of source emissions from biofilters showed concentrations in the raw and purified gases in the range of up to three orders of magnitude. The operational characteristics of the plants generally contributing to bioaerosol emissions on-site were found to have an influence on the concentration levels in the raw gas. A decrease in the microbiological parameters which may be regarded as specific for composting operations, was attributed to a reduced rate of passage through the biofilters. The magnitude of reduction as well as the concentrations varied greatly.

Air Microbiology↗
PubMed1999

[Comparative studies of airborne, cultivatable microorganisms at selected sites of waste managements, domestic animal husbandry and in the surrounding residential area].

During the last years, sampling of airborne microorganisms (including mesophilic bacteria, moulds, thermophilic bacteria and A. fumigatus) in waste disposal, recycling industry and control sampling locations in the urban and rural districts of Graz was conducted using Andersen 6-stage viable cascade impactors. In the present study additional sampling in livestock buildings has been conducted. Except mesophilic bacteria the emission in the area of waste disposal and recycling industry was significantly higher than in livestock buildings. In the surroundings of the livestock buildings the number of microorganisms was not increased, while the normal background level in the surroundings of the waste proceeding plants was reached from a distance of 150 to 300 meters.

Air Microbiology↗
PubMedDate not supplied

[On the vertical distribution of microorganisms in lake Baikal during spring deep-water renewal].

The vertical distribution of microorganisms during spring deep-water renewal in Lake Baikal was studied. The downward advection of trophogenic waters was found to create conditions for the extensive growth of microorganisms capable of decomposing and mineralizing organic carbon, nitrogen, and phosphorus in deep water layers. These processes occur annually at spring thermal bars near the underwater slope of Lake Baikal, whereas in its pelagic zone, the deep intrusions of waters rich in organic material are observed only in the years when enhanced deep-water renewal is accompanied by a high spring yield of phytoplankton.

Bacteria↗
PubMed1975

[A method of determining the efficiency of the projected process of uninterrupted microorganism cultivation for vaccine production].

The authors suggest the method of study of the process of periodic cultivation of microorganisms for prognostication of the optimal process of biomass accumulation at the level of microbial population, homogenous by the spectrum of biochemical properties. A regimen of continuous growth of the microorganisms (calculated with the use of this method), corresponding to the phase of delay of the growth rate, was economically more effective in comparison with the traditional process used in the vaccine production.

Bacteriological Techniques↗
PubMedDate not supplied

A comparison of the MicroCount Digital System to plate count and membrane filtration methods for the enumeration of microorganisms in water for pharmaceutical purposes.

The enumeration of microorganisms in water for pharmaceutical purposes using the MicroCount Digital System (Millipore Corporation, Bedford, MA) was compared to the USP-recommended Pour Plate and Membrane Filtration Count methods. A study, using a pure culture of Buckholderia cepacia, ATCC#25416, showed that the accuracy, precision, reproducibility and linearity of the MicroCount ATP Bioluminescence System was equivalent to or better than the traditional methods. When the MicroCount System was used to monitor purified water and water for injection taps in a pharmaceutical plant over a month, comparable counts to the traditional methods were obtained within 24 hours compared to 48 to 72 hours with the other methods. The effectiveness of the memory device used for the isolation of colonies for characterization was demonstrated by comparing the number and pattern of the positive wells in the MicroCount plates with the isolation of colonies on the microbial count agar plates. The recovery on agar plates, although slightly higher, was not statistically different to the MicroCount plates. The predominated microorganisms isolated using all three methods were Ralstonia pickettii, Bacillus sphaericus, Stenotrophomonas maltophia, and a Staphylococcus species.

Colony Count, Microbial↗
PubMedDate not supplied

[Verification of the proteolytic and lipolytic activities of the microbial flora isolated from raw, refrigerated, type B milk. II. Psychrotrophic microorganisms].

The aim of this work was to evaluate the microbiological quality of raw type B milk, kept under refrigeration at 3 degrees C, for a period of 15 days. The milk was enumerated and isolated a total of 180 microorganisms, of which 80 were psychrotrophics. The ability of these microorganisms to produce lipolysis and/or proteolysis in the milk was evaluated. Concerning the microbiological analysis, the samples analyzed presented high values for total counting. The results from the initial counting were 2.7 x 10(4) UFC/ml for psychrotrophic, with a predominance of Gram negative bacilli, which were highly lipolytic and had proteolytic activities associated.

Animals↗
PubMedDate not supplied

[Polarization state of the light source and determination of attenuated total internal reflection spectra in intact microorganisms].

The problems are considered of the interaction of linear polarized light current with undestroyed microorganisms while recording the spectra of attenuated total refraction(ATR) and repeated ATR (RATR). It is shown that proper allowance should be made of dichrosim of absorption bands of microorganisms during quantitative studies. Peculiarities of obtaining RATR spectra of the linearly polarized light source with polarization azinut other than 0 and 90 degrees are considered.

Actinomyces↗
PubMedDate not supplied

[Total count, biomass and production of microorganisms in the water of the South Sea].

The total number of microorganisms in waters of the Southern Ocean was determined by direct count in capillaries of Perfiliev and Gabe. Ninety samples of water, obtained at depths from 0 to 7,000 m in the Atlantic, Indian, and Pacific sectors of the Southern Ocean, have been analyzed. The number of microorganisms in these samples varied from hundreds to dozens of thousand cells in 1 ml of water, being in most cases thousands of cells in 1 ml of water. An increase in the concentration of cells, as compared to higher and lower horizons, was registered in some layers of subsurface, intermediate, and deep waters.

Bacteriological Techniques↗
PubMed2000

[Microorganisms isolated in cases of pertussis-like syndrome].

OBJECTIVE: To describe the etiologic study of the pertussis-like syndrome, not only as far as Bordetella genus is concerned but also regarding the causative role of other microorganisms for a 11-year period (1988-1998). METHODS: In all specimens from patients suffering from pertussis-like cough the presence of Bordetella spp., other bacteria, viruses, and mycoplasma was investigated. The analysed data included microbiological findings and epidemiologic issues (age, sex, hospital admission area, yearly distribution and seasonal period). RESULTS: A total of 1,063 specimens were investigated, most of them nasopharyngeal aspirates (910), corresponding to 905 patients; a positive culture was obtained form 56.9 of these patients. B. pertussis was isolated from 10.5% of patients. As for other bacteria, Haemophilus influenzae and Streptococcus pneumoniae were also isolated, in 16.9% and 15.8% of occasions, respectively. The respiratory syncitial virus was isolated from 10.7% of patients and other viruses in 9.4%. Among mycoplasma, Ureaplasma urealyticum predominated, with a recovery rate of 2.9%. The male/female ratio was 495/410; the ages of 67.2% of patients ranged from 0 to 6 months; a total of 689 (76.1%) required hospital admission. The recovery of B. pertussis and adenoviruses predominated during spring and summer months. In contrast, H. influenzae, S. pneumoniae and respiratory syncitial virus were recovered more frequently during winter months. CONCLUSIONS: Most patients with pertussis-like syndrome are children aged less than 6 months. The recovery percentages of B. pertussis and respiratory syncitial virus are identical and therefore we think that the investigation of their presence in this syndrome is fully warranted as well as the search for other microorganisms, since clinical symptoms are commonly non-specific among infants.

Age Distribution↗
PubMed1976

[Approach to a practical method for screening and identifying microorganism genera from urine (author's transl)].

In this study the author reported upon a practical new system for screening and identifying the microbial agents causing urinary tract infections. This system is composed of a combination of 3 screening procedures (pH-value + nitrite-test + catalase-test) and 8 selective culture media for the purpose of genus identification within 24 hours (Uripret-G). A total of 130 cultures was investigated. The employed microorganisms were mainly recovered from urine samples. They included the following species: Candida albicans, Citrobacter freundii, Enterobacter aerogenes, Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus inconstans, Proteus mirabilis, Proteus morganii, Proteus rettgeri, Proteus vulgaris, Serratia liquefaciens, Serratia marcescens, Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus faecalis and Streptococcus faecium. Employing coded cultures not only monoinfections but also multiinfections in urine samples were simulated. Under the circumstances of investigation it was possible with the help of the new system to reidentify the genera of all but two of the 130 employed microorganisms.

Bacteriological Techniques↗
PubMed2001

Partial spectrum of microorganisms found in dentures and possible disease implications.

While it would appear that denture surfaces alone become colonized by microorganisms, this study showed that the porosity of denture material allows for contamination throughout the entire denture. Further, the numerous opportunistic and pathogenic microorganisms found in this study were unexpected and are known to produce not only substantial oral infections, but also systemic diseases.

Bacterial Infections↗
PubMedDate not supplied

[Regulation of the biomass and activity of soil microorganisms by microfauna].

Microcosm experiments showed that the microbial biomass and the respiration activity in soil were regulated by nematodes. Depending on nematode number and plant residue composition, the trophic activity of nematodes can either stimulate or inhibit microbial growth and respiration as compared to soil containing no nematodes. The stimulating effect was observed when nitrogen-free (starch) or low-nitrogen (wheat straw, C:N = 87) organic substrates were applied. Inhibition occurred when a substrate rich in nitrogen (alfalfa meal, C:N = 28) was decomposed and the nematode population exceeded the naturally occurring level. A conceptual model was developed to describe trophic regulation by microfauna (nematodes) of the microbial productivity and respiration activity and decomposition of not readily decomposable organic matter in soil. The stimulating and inhibiting influence of microfauna on soil microorganisms was not a linear function of the rate of microbial consumption by nematodes. These effects are largely associated with the induced change in the physiological state of microorganisms rather than with the mobilization of biogenic elements from the decomposed microbial biomass.

Animals↗
PubMedDate not supplied

[Mineral salt-dependent inhibition of light emission from the luminescent microorganism Escherichia coli Z9051].

The influence of some mineral salts on the recombinant strain Escherichia coli Z9051 was investigated. It was shown that the composition (NaCl, Na2SO4, MgCl2 and MgSO4) and concentration (5 and 10%) of the salts substantially affect the expression of genes for the luminescence system of light-emitting bacteria cloned in the plasmid under the control of the lac-promoter. In some cases, the luminescence level of the microorganism in the presence of salts was similar to the luminescence level under catabolite repression by glucose, the more strong influence of the salts exceeding the effect of catabolite repression. The possibility of adaptation of the genetically modified microorganism to the salinity factor is discussed.

Chlorides↗
PubMed2000

[Antimicrobial effects of tea tree oil (Melaleuca alternifolia) on oral microorganisms].

The essential oil of Melaleuca alternifolia (tea tree oil) exhibits antimicrobial activity against a wide range of Gram-positive and Gram-negative bacteria, yeasts and fungi. In this study the bacteriostatic and bacteriocidal/fungicidal activity of a tea tree oil solution, of a new tea tree oil (Tebodont) and the respective placebo-gel, of a chlorhexidindigluconate-solution and of PlakOut was tested in vitro against ten different oral microorganisms. Minimum inhibitory concentrations were in the range from 0.0293% to 1.25% for the tea tree oil solution and from 0.0082% to 1.25% for the tea tree oil gel. The values for minimum bacteriocidal/fungicidal concentrations were in the range from 0.0521% to 2.5% for the tea tree oil solution and from <0.0098% to 3.33% for the tea tree oil gel. The most susceptible microorganisms were Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum, and Porphyromonas gingivalis, whereas Streptococcus mutans and Prevotella intermedia were the least susceptible ones. Both for the chlorhexidindigluconate solution and for PlakOut the values for the minimal inhibitory concentration and for the minimal cidal concentration were between <0.0002% and 0.0125%.

Anti-Infective Agents, Local↗
PubMed2001

[Effect of LAS on physico-chemical properties and microorganism activity in soil environment].

Using a well drained paddy soil and the derived soil under vegetables in the Taihu Lake region, China, experiments of soil capillary rise, colloid dispersion and adsorption of toxic organics and heavy metals by soil under various degrees of LAS addition were conducted. Also incubation experiments of microorganism activity in soil with added LAS in different concentrations were carried out in laboratory. LAS addition resulted in lower capillary rise of soil solution, higher dispersion of soil colloids and lower capacity of soil for organic pollutants but no significant influence on adsorption of heavy metal cations. The nitrification and amonification in soil were very sensitive to LAS stress while denitrification turned to be stimulated. LAS addition gave stronger growth of soil bacteria while decreased growth of fungus. Meanwhile, soil respiration was stimulated in the first week of incubation and compressed afterwards by LAS at concentration over 5 mg/kg. It seemed that some species of microorganisms were tolerant of LAS in the studied soils.

Alkanesulfonic Acids↗