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[Adaptation strategies of halophilic microorganisms and Debaryomyces hansenii (halophilic yeast)].

The term halophile is used for all those organisms belonging to hypersaline habitats; they constitute an interesting class of organisms able to compete successfully in salt water and to resist its denaturing effects. A wide diversity of microorganisms, prokaryotic and eukaryotic belong to this category. Halophile organisms have strategies allowing them not only to withstand osmotic stress, but also to function better in the presence of salt, in spite of maintaining high intracellular concentrations of salt, partly due to the synthesis of compatible solutes that allow them to balance their osmotic pressure. We describe the characteristics of some halophile organisms and D. hansenii (halophile yeast), that allow them to resist high concentrations of salt. The interest to know the great diversity microorganisms living in hypersaline habitats is growing, and has begun to be the center of recent investigations, since halophile organisms produce an wide variety of biomolecules that can be used for different applications. In this review we describe some mechanisms with which some halophile organisms count to resist the high concentration of salts, mainly NaCl.

Adaptation, Physiological↗

[Desugarization of egg white by microorganisms].

Glucose was eliminated from egg whites, using microorganisms, to prevent melanoidin formation which may damage the product. Desugarization was achieved by means of Acetobacter xylinum, Streptococcus lactis, Propionibacterium shermanii, Pr. petersonii and propionicacid cocci. Optimal conditions of desugarization were found, depending on the physiological characteristics of the above microorganisms. Propionibacterium shermanii may be well used to ferment a liquid egg white. These bacteria have no proteolytic properties and make no use of the egg white. They enrich the egg white with vitamin B12 and propionate, a preserving agent, during fermentation.

Acetobacter↗

In vitro inhibition of growth of neisseria gonorrhoeae by genital microorganisms.

The ability of microorganisms present in titers of over 10(5)/ml in the vaginal or cervical secretions to inhibit growth of N. gonorrhoeae in vitro was tested. Study of a strain of N. gonorrhoeae against 77 microorganisms demonstrated that most strans of S. epidermidis, S. aureus and the one "Gaffkya anaerobia" interfered with the growth of the N. gonorrhoeae. A minority of strains of S. viridans, Neisseria, Candida and Bifidobacterium demonstrated interference. No strains of enterococcus, diptheroids, aerobic Lactobacillus, Peptostreptococcus, Peptococcus, anaerobic Lactobacillus or Veillonella demonstrated interference.

Bacteria↗

[Distribution and activity of microorganisms in the deep repository for liquid radioactive waste at the Siberian Chemical Combine].

The physicochemical conditions, composition of microbial communities, and the rates of anaerobic processes in the deep sandy horizons used as a repository for liquid radioactive wastes (LRW) at the Siberian Chemical Combine (Seversk, Tomsk oblast), were studied. Formation waters from the observation wells drilled into the production horizons of the radioactive waste disposal site were found to be inhabited by microorganisms of different physiological groups, including aerobic organotrophs, anaerobic fermentative, denitrifying, sulfate-reducing, and methanogenic bacteria. The density of microbial population, as determined by cultural methods, was low and usually did not exceed 10(4) cells/ml. Enrichment cultures of microorganisms producing gases (hydrogen, methane, carbon dioxide, and hydrogen sulfide) and capable of participation in the precipitation of metal sulfides were obtained from the waters of production horizons. The contemporary processes of sulfate reduction and methanogenesis were assayed; the rates of these terminal processes of organic matter destruction were found to be low. The denitrifying bacteria from the underground repository were capable of reducing the nitrates contained in the wastes, provided sources of energy and biogenic elements were available. Biosorption of radionuclides by the biomass of aerobic bacteria isolated from groundwater was demonstrated. The results obtained give us insight into the functional structure of the microbial community inhabiting the waters of repository production horizons. This study indicates that the numbers and activity of microbial cells are low both inside and outside the zone of radioactive waste dispersion, in spite of the long period of waste discharge.

Bacteria↗

Determination of cervicovaginal microorganisms in women with abnormal cervical cytology: the role of Ureaplasma urealyticum.

OBJECTIVE: To evaluate the existence of an association between cervicovaginal infections and precancerous lesions of the uterine cervix, through determination of prevalent cervicovaginal micro-organisms, alone and in association with human papillomavirus (HPV), in patients with abnormal and normal vaginal cytology. PATIENTS AND METHODS: Patients with abnormal vaginal cytology were divided into three study groups according to cytological findings: ASC-US, L-SIL and H-SIL. All patients underwent colposcopic examination and exoendocervical and vaginal sampling for microbiological and molecular analysis for detection of HPV-DNA, Ureaplasma urealyticum, Chlamydia trachomatis, Trichomonas vaginalis, mycetes and common bacteria. Results were compared with the patient group asymptomatic for cervicovaginal inflammation with negative vaginal cytology and colposcopy. RESULTS: A high association between Ureaplasma urealyticum infection and the grade of cytological cervical lesion (27% for ASC-US, 35% for L-SIL and 45% for H-SIL) was found. Furthermore, 19% of the control group samplings were positive for Ureaplasma urealyticum, significantly less than that observed in the positive cytology groups. An interesting association of HPV with Ureaplasma urealyticum in patients with H-SIL vaginal cytology (83%), much higher than that observed in patients with slightly abnormal or normal vaginal cytology (56% for ASC-US, 49% for L-SIL, 40% for normal cytology) was also identified. In contrast, the association between Papillomavirus and multiple microorganisms seemed to decrease with the level of cellular dysplasia in 30% of controls, 33% of ASC-US, 32% of L-SIL and 17% of H-SIL. CONCLUSION: The presence of a high Ureaplasma urealyticum level seems to be a cofactor of HPV infection, a necessary cause of precancerous lesions of the uterine cervix. The presence of Ureaplasma urealyticum may play a role both in initiating viral cellular anomalies and in viral persistence. It can be hypothesized that these initial processes are helped by a state of cervical inflammation, also supported by multiple microorganisms. It would, thus, be suggested for all patients who present with an abnormal PAP test to undergo a cervicovaginal microbiological examination to detect potentially pathogenic microbes for correct diagnosis and treatment, as well as a more complete follow-up of cervical cytological lesions.

Adolescent↗

[Microorganisms synthesizing enzymes with thrombolytic action].

The literary and experimental data obtained by the authors concerning the ability of various microorganisms to synthesize exoproteases lysing the thrombi of human blood are presented in the article. Various methods of enhancing the thrombolytic activity of microorganisms cultures, the properties of some isolated and purified preparations, methods of enlarging the specificity of the enzymes to fibrin and of reduction of their toxicity are considered.

Bacteria↗

[Sensitivity of surface microorganisms to disinfectants].

The influence of humidity and temperature on survival of S. aureus and P. aeruginosa on the surfaces of titles, glass and blanket carriers has been estimated. The number of CFU was examined after exposure time 6 and 24 hours in temperatures of 21 degrees C, 37 degrees C and RH 35%, 95%. It was observed: 1. The important reduction of numbers of both microorganisms at temperature 37 degrees C and RH 95%, 2. The relatively high number of survival cells of P. aeruginosa on the surface of blankets at temp. 21 degrees C and RH 95%. The microorganisms on the carriers were previously kept for 24 h at temp. 21 degrees C, RH 35% and 95% and then exposed to solutions of chloramine, formalin, lysol and Sterinol (QAC). It was observed that there was a great dependence of the disinfecting effect on the degree of dessication of the surfaces. In all cases the resistance of contaminated carriers stored 24 h was higher at 95% RH than at 35% RH.

Bedding and Linens↗

[Identification of species of microorganisms of the genus Vibrio].

During 1988, a study was made on 61 microorganisms, genus Vibrio, which were received at the National Reference Laboratory for Acute Diarrheic Diseases. Pedro Kouri Institute of Tropical Medicine. Of them, 46 were from children with acute diarrheic disease and 15 were isolated from the environment. By means of biochemical tests. 61 Vibrio cholerae No. 01. 9 Vibrio parahaemolyticus and 1 Vibrio alginolyticus were identified. Emphasis is placed upon the importance of keeping a systematic surveillance upon these microorganisms in Cuba.

Animals↗

[The etiopathogenesis of periodontal diseases: the role of microorganisms. A review].

The microbiology of periodontal diseases as well as associations between certain microorganisms and types/stages of periodontal diseases are discussed and the ecology and the composition of the subgingival plaque are included in this discussion, too. Furthermore, the possible role of microorganisms associated with periodontal diseases, their pathogenic mechanisms and their virulence factors are treated in the present article. Periodic upsets of the host-parasite equilibrium seem to be responsible for the bursts of disease progression. Several plaque hypotheses (specific, non-specific, opportunistic) have been proposed as likely models to explain the nature of periodontal infections and diseases. However, none of these theories is widely accepted at the moment. Therefore, we suggest that further investigations concerning the complex bacterial interactions and the manner in which the host responds to the mass and the composition of the dental plaque must be carried out in the future.

Adolescent↗

[Ultrastructural changes in neutrophils and anaerobic microorganisms during their interactions in experimental acute intestinal obstruction].

The authors established that 12 h after development of acute obstructive ileus in inactive neutrophil granulocytes (NG), the anaerobic microorganisms were intact, or at the process of division; in the active NG, they were destroyed, or when forming "halo", might preserve and migrate in the matrix of NG. In interaction of NG with microorganisms, the numerous oval and roundish bacterial bodies with a diameter of 0.2-0.5 micron capable to penetrate into the non-phagocytic cells are formed. A function of the formations revealed is not studied.

Acute Disease↗

Experimental allergic alveolitis after exposure to different microorganisms.

The experiments described here examined the capacity of different microorganisms to induce allergic alveolitis. Guinea-pigs were exposed to an aerosol of pure cultures of five different organisms, four of which are common in mouldy hay, without previous injection of an adjuvant. The animals were either acutely exposed or exposed for 3 to 5 weeks, after which the numbers of different inflammatory cells in the airways were counted and histological changes in the lung parenchyma were assessed. It was seen that prolonged exposures to large numbers of spores produced a cellular infiltration in the alveolar and bronchiolar region, and gave rise to lesions resembling early granulomas. The number of lymphocytes increased in the airways. The results suggest that allergic alveolitis can be induced by inhalation of various kinds of microorganisms and that these may vary in their capacity to produce the disease.

Allergens↗

[The effect of an ozone-oxygen mixture on Mycobacterium tuberculosis and conditionally pathogenic microorganisms].

The impact of a gaseous ozone-oxygen mixture (OOM) on Mycobacterium tuberculosis (MBT) and opportunistic microorganisms was studied. It was demonstrated that on 15- and 30-min exposure, OOM caused a significant decrease in the number of colonies of the grown microorganisms as compared with the control. The OOM mixture produced the highest effect of the MBT suspension, which is likely to be related to a greater surface of ozone contact with a cell than with a dense medium, and higher concentration of ozone and its highly active radicals that arise from a treatment process. After treatment with a gaseous mixture, 80-90% of the microbial cells lost their reproductive ability. The strains grown after OOM action retain drug sensitivity of the original strain. The results suggest that the use of a gaseous OOM mixture is promising in the treatment of tuberculosis to cleanse the destruction cavities and pleural empyemas, including those of nonspecific etiology.

Drug Combinations↗

Airborne microorganism monitoring: a comparison of several methods, including a new direct counting technique.

Samples of aerosol from the surrounding air were collected by forcing them to impact onto a solid nutrient medium, onto membrane filters, or onto microscope slides on microcover slips. The samples were cultivated or viewed in a fluorescence microscope by using a technique developed by us, or investigated by scanning electron microscopy. The amounts of microorganisms found by cultivation method, i.e. those forming microcolonies (CFU), were on average 85% lower than the amounts determined by the fluorescence technique. Cultivation of microorganisms trapped on Synpor filters of various pore size resulted in lower counts than conventional cultivation. Among bacteria, the genera Micrococcus, Bacillus and Corynebacterium predominated; the genera Neisseria, Actinomyces, Pseudomonas and others were also found. Of micromycetes, the genera Penicillium, Aspergillus and Cladosporium occurred most frequently in air. In the summer season, yeasts and other micromycetes prevailed, whereas in the winter season the bacteria counts were higher. The total counts of all components of the aeroplankton were higher in summer than in winter. Dust particles bounded mainly bacteria.

Aerosols↗

[The role of different microorganisms and infectious processes in the occurrence and course of bronchial asthma].

The role of infection in bronchial asthma (BA) is unknown. The pathogenesis of BA contributes to the origin of infectious processes induced by different microorganisms. In view of the predominance of associations of viruses and bacteria in the etiology and pathogenesis of acute respiratory infections, it is difficult to define in vivo the share and role of these microorganisms which participate in the origin and enhancement of hypersensitivity, hyperreactivity and alterations in beta-adrenoreactivity. Some factors of bacterial pathogenicity promote BA progress. On contact with basophils and mast cells bacteria (both pathogenic ones and ordinary commensals) are capable of liberating histamine and other mediators during colonization of the bronchial tree and origin other infectious process. This mechanism of mediator liberation may contribute to the transformation of pre-asthma to BA or provoke its exacerbation.

Asthma↗

[The effect of dexamethoxin on the integrity of cytoplasmic membrane in gram-positive and gram-negative microorganisms].

Decamethoxin is shown to be able to increase membrane permeability of Pseudomonas aeruginosa, Escherichia coli and Micrococcus lysodeikticus, that is confirmed by a loss of compounds with the absorption maximum at 260 nm by cells. Parallel with this the number of viable individuals has fallen and activity of dehydrogenases has been inhibited. The aspartate and alanine aminotransferase activity was not inhibited by decamethoxin and even increased. Decamethoxin lysed the protoplasts of the tested microorganisms. At high decamethoxin concentrations (over 500 micrograms/ml for P. aeruginosa and over 200 mu/ml--for E. coli) the outflow of components from the cells of gram-negative bacteria ceased, that may be associated with the coagulation changes in the cytoplasm. A loss of the low-molecular components by M. lysodeikticus cells and lysis of protoplasts proceeded less intensely than the same processes in the gram-negative microorganisms, that is explained by a less resistance of M. lysodeikticus to decamethoxin and earlier coagulation of the cytoplasm preventing lysis.

Anti-Bacterial Agents↗

Antibacterial effect of some combinations of pesticides of pure cultures of microorganisms.

The investigations conducted showed that the antibacterial effect of dinitro-o-cresol, cuprozane, and trichlorfon is due to their chemical structure and to the species of microorganisms on which they act. Dinitro-o-cresol and Cuprozane possess selective toxicity with respect to B. anthracis and Rh. gracilis and cuprozane with respect to Ch. perfringens. The method of evaluating the effect of combinations of chemical compounds consisting of two or more components which have been developed made it possible to detect the antibacterial effect of mixtures consisting of the indicated pesticides. It was established that the combinations studied possess synergic and additive effects, which also depend on the chemical structure of the pesticides and the species of microorganisms.

Bacillus↗

The role of microorganisms in atopic dermatitis.

The course of atopic dermatitis is widely determined by environmental factors such as physical or psychogenic stress and reactions to allergens or microorganisms. The latter include bacteria, viruses and fungi, especially Staphylococcus auerus, Herpes simplex virus (HSV), and Pityrosporum orbiculare. In childhood, Impetigo around the big joints is frequently seen, while the characteristic reaction to S. auerus in the young adults is pruritic pustules on the extremities or an exacerbation of the eczema to an exudative dermatitis. Similarily, P. orbiculare may induce a flare-up of the eczema of the head and neck, while HSV may cause a true wide-spread infection known as eczema herpeticum. An immunological disorder, a fragile skin, and special properties of the microorganism may account for the altered response to infection or severe colonization in the patient with atopic eczema. During exacerbations of the eczema, supplementary treatment with proper antimicrobial agents has been shown to be of great value.

Bacterial Physiological Phenomena↗

Solution hybridization assay for detecting genetically engineered microorganisms in environmental samples.

A solution hybridization method was developed for detecting genetically engineered microorganisms in environmental samples. The detection method involves recovery of DNA from the microbial community of an environmental sample followed by hybridization in solution with a radiolabeled RNA gene probe. After nuclease digestion of non-hybridized probe RNA, the DNA-RNA hybrids formed in the solution hybridization reaction are separated by sephadex or hydroxyapatite column chromatography and detected by liquid scintillation counting. Using solution hybridization-gene probe detection, as few as 100-1000 target cells per gram sediment sample of a 2,4,5-T-degrading genetically engineered microorganisms could be detected.

Chromatography, Gel↗