Structure of the antibiotic resistance of the salmonellae found in Transcarpathia]

Resistance of 1280 strains of Salmonella of various serological types isolated in the Zakarpatskaya region within 1967-1976 was studied with respect to benzylpenicillin, streptomycin tetracycline, levomycetin, monomycin, neomycin, erythromycin and oleandomycin. An Increase in the resistance of Salmonella to streptomycin, tetracycline, levomycetin, monomycin and neomycin was shown. During the last years Salmonellae carrying 4-8 resistance determinants were spreading in the region. Among S. typhimurium strains with 7-8 resistance determinants predominated (58.8 per cent). The cases of salmonollosis were mainly due to these strains.     

Biofixation of carbon dioxide by Spirulina sp. and Scenedesmus obliquus cultivated in a three-stage serial tubular photobioreactor

The increase in the concentration of atmospheric carbon dioxide is considered to be one of the main causes of global warming. As estimated by the Intergovernmental Panel on Climate Change (IPCC) criteria, about 10-15% of the gases emitted from the combustion coal being in the form of carbon dioxide. Microalgae and cyanobacteria can contribute to the reduction of atmospheric carbon dioxide by using this gas as carbon source. We cultivated the Scenedesmus obliquus and Spirulina sp. at 30 degrees C in a temperature-controlled three-stage serial tubular photobioreactor and determined the resistance of these organisms to limitation and excess of carbon dioxide and the capacity of the system to fix this greenhouse gas. After 5 days of cultivation under conditions of carbon limitation both organisms showed cell death. Spirulina sp. presenting better results for all parameters than S. obliquus. For Spirulina sp. the maximum specific growth rate and maximum productivity was 0.44 d(-1), 0.22 g L(-1)d(-1), both with 6% (v/v) carbon dioxide and maximum cellular concentration was 3.50 g L(-1) with 12% (v/v) carbon dioxide. Maximum daily carbon dioxide biofixation was 53.29% for 6% (v/v) carbon dioxide and 45.61% for 12% carbon dioxide to Spirulina sp. corresponding values for S. obliquus being 28.08% for 6% (v/v) carbon dioxide and 13.56% for 12% (v/v) carbon dioxide. The highest mean carbon dioxide fixation rates value was 37.9% to Spirulina sp. in the 6% carbon dioxide runs.     

Gas Exchange of Algae: III. Relation between the Concentration of Carbon Dioxide in the Nutrient Medium and the Oxygen Production of Chlorella pyrenoidosa

The oxygen production of a photosynthetic gas exchanger containing Chlorella pyrenoidosa (1% packed cell volume) was measured when various concentrations of carbon dioxide were present within the culture unit. The internal carbon dioxide concentrations were obtained by manipulating the entrance gas concentration and the flow rate. Carbon dioxide percentages were monitored by means of electrodes placed directly in the nutrient medium. The concentration of carbon dioxide in the nutrient medium which produced maximal photosynthesis was in the range of 1.5 to 2.5% by volume. Results were unaffected by either the level of carbon dioxide in the entrance gas or the rate of gas flow. Entrance gases containing 2% carbon dioxide flowing at 320 ml/min, 3% carbon dioxide at 135 ml/min, and 4% carbon dioxide at 55 ml/min yielded optimal carbon dioxide concentrations in the particular unit studied. By using carbon dioxide electrodes implanted directly in the gas exchanger to optimize the carbon dioxide concentration throughout the culture medium, it should be possible to design more efficient large-scale units.     

Antibiotic sensitivity of the bacterial microflora from the sputum of children with acute pneumonia]

Bacteriological analysis of sputum of 598 children with acute pneumonia was performed. Sensivity of 1348 cultures belonging to 8 bacterial species with respect to benzylpenicillin, streptomycin, chloramphenicol, tetracycline, oxytetracycline, chlortetracycline, erythromycin, oleandomycin, neomycin and monomycin was determined. It was shown that the sputum microflora was often resistant to the antibiotics widely used in the medical practice for prolonged periods of time, such as benzylpenicillin, streptomycin, chloramphenicol, tetracyclines. However, it usually remained sunsitive to neomycin, monomycin, erythromycin and oleandomycin. It was found that antibioticogrammes defining the antibiotic choice were of great significance for therapy of acute pneumonia.     

Experimental characteristics of the antileishmaniasis action of amphotericin B]

The efficacy of amphotericin B powder of the Soviet production was studied as a therapeutic agent in experimental zoonotic leishmaniosis of the skin form of mice and hamsters. Amphotericin B was administered per os and its action was compared with that of monomycin injected subcutaneously (50 mg/kg). Amphotericin B in a dose of 150 mg/kg administered for 30 days protected 96+/-0.07 and 76.4+/-0.9 per cent of the mice and hamsters respectively from development of the leishmaniosis clinical signs, 68.8+/-0.04 per cent of the animals being cured (in the treatment experiments). The effect of the antibiotic was analogous to that of monomycin administered parenterally. The study of the kinetics of amphotericin B showed that the antibiotic was well absorbed from the digestive tract of the animals into the blood which provided the chemotherapeutic effect.     

Effect of dissolved carbon dioxide on penicillin fermentations: Mycelial growth and penicillin production

The effect of dissolved carbon dioxide on the specific growth rate and the penicillin production rate of Penicillium chrysogenum was examined experimentally. The dissolved carbon dioxide was found to inhibit the specific growth rate and the penicillin production rate when the aerated submerged penicillin fermentation was exposed to influent gases of 12.6 and 20% carbon dioxide, respectively. Upon exposure to influent gases of 3 and 5% carbon dioxide, no pronounced metabolic inhibition was noted.     

Antibiotic sensitivity of Shigella isolated from patients from 1974-1985

Antibiotic sensitivity of 3524 Shigella cultures isolated from patients in 1974-1982 and 414 cultures isolated in 1983-1985 was assayed with standard paper disks. The isolates of 1974-1982 were mostly responsive to ampicillin, carbenicillin, kanamycin, gentamicin, monomycin, neomycin and chloramphenicol. Certain differences in the level of the antibiotic resistance were observed in the Shigella isolates belonging to diverse species. Polyresistant cultures of Shigella amounted to 96.5% and ranged from 88.5 to 99.4% in different years. The number of the cultures with multiple resistance among Shigella sonnei was somewhat higher than that among the Flexneri and Newcastle bacilli. The Shigella isolates of 1983-1985 were mostly responsive to gentamicin, carbenicillin, neomycin, kanamycin and monomycin. 55.5% of the Shigella isolates were responsive to chloramphenicol and only 3.1% to tetracycline. Almost all the causative agents of dysentery isolated within that period were polyresistant. Phenotypic characteristics of multiple resistance in the Shigella cultures were studied.     

Biological properties of sherry yeasts in the presence of antimicrobial preparations

The wine yeasts Cheres were not sensitive to high concentration (500 gamma/ml) of benzylpenicillin, streptomycin, tetracycline, oxytetracycline, chlortetracycline, morphocycline, erythromycin, oleandomycin, monomycin, neomycin, kanamycin, polymyxin, ampicillin, oxacillin, methicillin, ceporin, ristomycin, levomycetin, furadonin and furazolidone. In concentrations of 50 to 500 gamma-ml oleadomycin, chlortetracycline, oxytetracycline, kanamycin and ristomycin inhibited synthesis of the Cheres yeast biomass. Benzylpenicillin, polymyxin, neomycin and ampicillin in concentrations of 50 to 100 gamma/ml had a stimulating effect on the yeast biomass synthesis.     

Photoproduction of Hydrogen by the Marine Heterocystous Cyanobacterium Anabaena Species TU37-1 Under a Nitrogen Atmosphere

Hydrogen production rates by Anabaena sp. strain TU37-1 obtained after an initial 1-day incubation period were approximately 70 to 80 and 3 to 9 µmol (mg chl)^–1 h^–1 under argon and nitrogen atmospheres, respectively. Hydrogen production under argon was not enhanced by addition of carbon dioxide, but was enhanced to some extent under nitrogen by increasing the initial carbon dioxide concentration. Rates of hydrogen and oxygen production during the initial 7-hour period were 15 and 220 µmol (mg chl)^–1 h^–1, respectively, in vessels with 18.5% initial carbon dioxide. Hydrogen production under nitrogen was enhanced by addition of carbon monoxide (1%). The rate obtained from the initial 1-day incubation period was about 40 µmol (mg chl)^–1 h^–1, which corresponded to about 60% of that under argon. On the basis of these observations, a possible strategy for hydrogen production by nitrogen-fixing cyanobacteria under nitrogen in the presence of carbon monoxide is indicated.     

The role of ethylene and carbon dioxide in differentiation of shoot buds in excised cotyledons of Pinus radiata in vitro

The production of ethylene and carbon dioxide by Pinus radiata D. Don cotyledons cultured on shoot-forming medium in sealed Erlenmeyer flasks was studied. To establish the role of these gases on morphogenesis three experimental approaches were used: (1) capping the flasks with serum caps on various days, and removing the serum caps at different stages of morphogenesis, (2) absorbing the gases by setting up traps singly and in combination during the various stages of differentiation and (3) incubating the cultures under continuous flow of constant gas mixtures. The results indicate that both ethylene and carbon dioxide, which build up during the first 10 to 15 days of culture, promote morphogenesis. Excessive accumulation after the initiation of buds causes some degree of dedifferentiation. When both the gases were eliminated from the flasks, bud formation and growth were inhibited. In the absence of oxygen, ethylene and carbon dioxide fail to influence growth and morphogenesis.     

Antibiotic sensitivity of the H- and O-forms of bacteria in the genus Proteus]

Proteus strains isolated from the gastro-intestinal tract of children not older than 1 year were characterized by resistance to oxytetracycline, chlortetracycline, benzylpenicillin and erythromycin. The strains were more sensitive to neomycin, monomycin and streptomycin. Antibiotic sensitivity of Pr. mirabilis and Pr. vulgaris strains increased on transfer from H- to O-form. Inverse dependence of the urease activity of the strains on their sensitivity to tetracyclines was noted.     

Construction and performance of plug-in membrane inlet mass spectrometer for fermentor monitoring

An in situ sterilizable plug-in membrane inlet mass spectrometer for monitoring dissolved gases and volatiles in fermentors was constructed and tested. The design ensured a minimal distance to be traveled by analyte molecules from the bulk of the fermentation broth to the ionization chamber of the mass spectrometer. Apart from the specific cross talk due to overlapping mass peaks from different compounds, we found that carbon dioxide interfered unspecifically with all the mass peaks of other substances, changing them by the same factor. The interference changed slowly with time and could be positive or negative depending on the history of the mass spectrometer. Also, the general sensitivity of the instrument changed slowly with time. These effects can be neglected or corrected for empirically in short-term measurements. When the fermentor was aerated with a three-component gas mixture including carbon dioxide, a rapid change in the partial pressure of carbon dioxide in the gas mixture gave rise to a transient in the signal of a gas whose partial pressure was kept constant. This effect revealed a transient change in the composition of the gas mixture in the bubbles caused by net import or export of carbon dioxide during equilibration with the new gas mixture. An experimental method to determine the effective partial pressures of gases in the bubbles during steady-state transport of carbon dioxide was designed. The plug-in membrane inlet mass spectrometer was tried as a probe for oxygen and ethanol in an oxystatic culture of the yeast Pichia stipitis. We found that it was possible to keep a steady-state concentration of as little as 0.5 muM throughout the lifetime of the culture. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 54: 535-542, 1997.     

Influence of Pathological Concentrations of Ammonia on Metabolic Fate of 14C-Labeled Glutamate in Astrocytes in Primary Cultures

Rates of glutamine formation and of carbon dioxide production (as an indication of oxidative deamination of glutamate) were determined in primary cultures of astrocytes exposed to 50 microM labeled glutamate in the absence or presence of added ammonia (0.1-3 mM). Glutamine formation (1.7 nmol/min/mg protein) was unaffected by all concentrations of added ammonia. This probably reflects the presence of a low content of ammonia (0.1-0.2 mM), originating from degradation of glutamine, in the cells even in the absence of added ammonia, and it shows that pathophysiological concentrations of ammonia do not increase the formation of glutamine from exogenous glutamate. The carbon dioxide production rate was 5.9 nmol/min/mg protein, i.e., three to four times higher than the rate of glutamine formation. It was significantly reduced (to 3.5 nmol/min/mg protein) in the presence of 1 mM or more of ammonia. This is in keeping with suggestions by others that toxic levels of ammonia affect oxidative metabolism.     

Dose responses of tsetse flies (Glossina) to carbon dioxide, acetone and octenol in the field

ABSTRACT Studies were conducted in Zimbabwe of the catch of Glossina pallidipes Austen from an electric net plus target baited with mixtures of acetone plus carbon dioxide or 1-octen-3-ol (octenol) plus carbon dioxide. For acetone dispensed alone at 5–50, 000 mg h^-1, ten-fold increments in the dose increased the catch 1.7 times. For carbon dioxide dispensed alone, dose increments from 12 to 1201 h^-1 doubled the catch, but the catch was not further increased by dispensing carbon dioxide at 600–1200 1 h^-1. For mixtures of these two odours, ten-fold increments in the dose of carbon dioxide between 12 and 12, 0001 h^-1 increased the catch c . 2.5 times if acetone was also dispensed at >50 mg h^-1; changes in the dose of acetone between 50 and 50 000 mg h^-1 did not affect the catch. The addition of octenol (0.05 mg h^-1) to carbon dioxide (12–12001 h^-1) doubled the catch. Ten-fold increments in the dose of octenol between 0.05 and 5 mg h^-1 did not increase the catch significantly and the catch was independent of changes in the dose of carbon dioxide between 120 and 12001 h^-1. The behavioural basis of the dose-response curves was investigated using an incomplete ring of electric nets to assess the flight orientation of tsetse in different odours. Upwind flight was not elicited by acetone or octenol alone, or by carbon dioxide unless it was at very high doses, however, mixtures of carbon dioxide with acetone or octenol elicited upwind flight. It is suggested that the attractiveness of mixtures of acetone and carbon dioxide is a function of the region of overlap of these two odours at above threshold concentration. Acetone and octenol on their own appear to increase the responsiveness of flies to visual cues.     

Antibiotic sensitivity of Proteus, Pseudomonas pyocyanea and staphyloccoci isolated from scleroma and ozena patients]

Antibiotic sensitivity of 292 strains of Proteus, 60 strains of Ps, aeruginosa, 309 strains of S. aureus and 88 strains of S. epidermidis isolated from the upper respiratory tract of patients with scleroma and ozena was studied. The cultures of Pr. mirabilis were sensitive to aminoglucosides (54.9-96.2 per cent) and Pr. morganii were sensitive to levomycetin (81.5 per cent) and neomycin (92.6 per cnet). Sensitivity of Pr. vulgaris and Pr. morganii was reliably higher (p less than 0.001) than that of Pr. mirabilis. The strains of Pr. morganii were less sensitive to monomycin (P less than 0.001) and streptomycin (p less than 0.01) as compared to the cultures of other Proteus species tested. The strains of Ps. aeruginosa were sensitive only to gentamicin (90 per cent) and neomycin (81.1 per cent). Most of the strains of S. aureus (85.4-100 per cent) were sensitive to oleadomycin, erythromycin, olemorphocycline, tetraolean, oxacillin, methicillin ceporin, lincomycin, ristomycin, kanamycin, monomycin and gentamicin. Benzylpenicillin (90.8 per cent of the sensitive strains), ampicillin (67.1 per cent), tetracycline (66.7 per cent), levomycetin (68.6 per cent) and streptomycin (38.1 per cent) were less effective. Antibacterial therapy in cases with scleroma and ozena should be directed not only against causative agents of the diseases but also against the microbes developing due to disbacteriosis. Combination of parenteral and local use of the antibiotics in the treatment of chronic clebsiellesis decreased the isolation rate of Proteus and Ps. aeruginosa in the patients.     

Laboratory composting of extruded starch acetate and poly lactic acid blended foams

Composting of extruded foams made of starch acetate and poly lactic acid (PLA) with pre-conditioned yard waste was studied using a laboratory composting system. Extruded foams of high amylose starch were used as the control. Degradation was measured by analyzing the exhaust gases for carbon dioxide. There were significant differences in the amounts of carbon dioxide produced in the vessels containing foams of high amylose starch and foams of starch acetate blended with 20% or 30% PLA. The high amylose starch foams completely degraded within 15 days. The starch acetate foams with 0% PLA took longer, with evolution of carbon dioxide still measurable after 55 days. The rate of degradation was faster for foams with higher PLA contents. The starch acetate foams took even longer to degrade. The maximum time was found to be 130 days for the starch acetate foams.     

Laboratory composting of extruded poly(lactic acid) sheets

Composting of extruded poly(lactic acid) (PLA) in combination with pre-composted yard waste in a laboratory composting system was studied. Yard waste and PLA mixtures containing 0%, 10%, or 30% PLA (dry weight basis) were placed in composting vessels for four weeks. Exhaust gases were analyzed for carbon dioxide concentration twice per week. After the first week, significantly greater (P < 0.05) amounts of carbon dioxide were generated in vessels with 10% or 30% PLA than in control (0% PLA) vessels. Data indicated that microbial degradation of PLA occurred. There was no significant difference (P > 0.05) in carbon dioxide emission between 10% and 30% PLA mixtures. Compost pH dropped (from 6.0 to 4.0) after 4 weeks of composting for 30% PLA, but remained unchanged (6.3) for 0% or 10% PLA. Most likely, in the case of 30% PLA, substantial chemical hydrolysis and lactic acid generation lowered the compost pH. The lowered pH likely suppressed microbial activity, thus explaining the lack of difference in carbon dioxide emissions between 10% and 30% PLA mixtures. Gel permeation chromatography showed a notable decrease in PLA molecular weight as a result of composting. It was demonstrated that PLA can be efficiently composted when added in small amounts (<30% by weight) to pre-composted yard waste.     

Effects of plasma cholesterol lowering agents on hepatobiliary lipid metabolism and cholesterol turnover in the rhesus monkey.

The effects of clofibrate, cholestyramine, and neomycin on hepatobiliary lipid metabolism were studied in adult rhesus monkeys in metabolic steady state with intact but exteriorized enterohepatic circulations. Clofibrate (30 mg/kg, id) had no effect on lipid secretion while cholestyramine (150 mg/kg, id) decreased biliary cholesterol secretion rate from 0.19 +/- 0.03 to 0.13 +/- 0.02 mmol/24 h, p less than 0.05. Neomycin (30 mg/kg, id) decreased bile flow from 216 +/- 10 to 191 +/- 7mL/24 h, p less than 0.05, and tended only to decrease bile salt and phospholipid secretion rates. Cholestyramine decreased cholesterol composition from 1.81 +/- 0.22 to 1.30 +/- 0.22 mol %, p less than 0.05, while clofibrate and neomycin had insignificant effects. Cholestyramine and neomycin decreased bile salt pool size from 1 +/- 0.1 to 0.77 +/- 0.15 and from 1.45 +/- 0.16 to 1.13 +/- 0.21 mmol, p less than 0.05, respectively, while clofibrate had no effect. Bile salt synthetic rate was increased only by cholestyramine, i.e., from 0.63 +/- 0.04 to 1.48 +/- 0.26 mmol/24 h, p less than 0.01. Concomitant cholesterol turnover studies revealed that cholestyramine increased the production rate and excretion of cholesterol in the rapidly miscible cholesterol pool and increased the transfer of cholesterol from slow to rapidly miscible pools. Neomycin, on the other hand, decreased the size of the rapidly miscible pool by decreasing production rate without affecting the size of the slowly miscible pool, while clofibrate had insignificant effects.     

Microbiological processes at the interface of aerobic and anaerobic waters in the deep-water zone of the Black Sea

Chemical and key microbiological processes (assimilation of carbon dioxide, oxidation and formation of methane, and sulfate reduction) occurring at the boundary between the aerobic-anaerobic interface in the deep-water zone of the Black Sea were investigated. Measurements were taken at depths from 90 to 300 m at intervals of 5-10 m. The integral rate of the dark assimilation of carbon dioxide varied from 120 to 207 mg C/(m2 day) with a maximum at the boundary of cyclonic currents. The organic matter (OM) formed from methane comprised less than 5% of the OM formed from carbon dioxide. A comparison between the rates of methane oxidation and methane production suggests that methane that is oxidized at depths from 100 to 300 m was formed in deeper water horizons. The maximum rate of sulfate reduction (1230 mg S/(m2 day)) was observed in the western halistatic region, and the minimum rate (490 mg S/(m2 day)), in the eastern halistatic region. The average rate of hydrogen sulfide production measured at three deep-sea stations amounted to 755 mg S/(m2 day), or 276 g S/(m2 year).     

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.