Phagocytosis of chloramine B sensitive and resistant staphylococci isolated from healthy persons and patients

Phagocytic reaction with respect to antibiotic and chloramine B sensitive and resistant staphylococci isolated from healthy persons and patients, air and stock of medical institutions was studied on albino mice. It was shown that the staphylococcal isolates included strains simultaneously sensitive to antibiotics and chloramine, sensitive to antibiotics and resistant to chloramine, resistant to antibiotics and sensitive to chloramine and simultaneously resistant to antibiotics and chloramine. Activity, intensity and completeness of phagocytosis by leucocytes from mouse abdominal cavity exudates with respect to the staphylococcal strains sensitive to antibiotics and resistant to chloramine, resistant to antibiotics and sensitive to chloramine and simultaneously resistant to antibiotics and chloramine were lower than the values of the phagocytic reaction with respect to the isolates simultaneously sensitive to antibiotics and chloramine. This suggested that not only antibiotic resistance of microbes but also their resistance to disinfectants could be referred to complicating factors of hospital infections.     

Sensitivity to antibiotics and the disinfectant chloramine of Staphylococci isolated from healthy and sick persons

Five hundred and twenty seven strains of Staphylococcus aureus with massive contamination of at least 10(3) when estimated quantitatively were tested for their sensitivity to antibiotics and chloramine B. The staphylococcal strains were isolated from patients, air and stock of rooms in medical institutions, from medical personnel and healthy persons having no long-term contacts with hospital media i. e. from pregnant women and workers of confectionery plants. Among the isolates there were strains simultaneously sensitive to antibiotics and chloramine B (16.6 per cent), sensitive to antibiotics but resistant to chloramine B (5.5 per cent), resistant to antibiotics but sensitive to chloramine B (63.1 per cent) and resistant to antibiotics and chloramine B (15.3 per cent). Staphylococci resistant simultaneously to antibiotics and chloramine B were isolated from the persons of all the groups and from the air and stock of the rooms in the medical institutions. This showed the necessity of controlling sensitivity or staphylococci circulating in hospital media not only to antibiotics but also to disinfectants for providing more efficient prophylaxis of intrahospital infections.     

The sensitivity to antibiotics and chloramine B of opportunistic microorganisms isolated from patients

Strains of staphylococci, klebsiella, proteins, blue pus bacillus and enterobacteria resistant not only to antibiotics but also to chloramine, a disinfectant, were isolated from the test material samples obtained from patients with different purulent-inflammatory processes. The following strains are revealed among the test microorganisms: sensitive simultaneously to antibiotics and chloramine; sensitive to antibiotics but resistant to chloramine; sensitive to chloramine but resistant to antibiotics; simultaneously resistant both to antibiotics and chloramine.     

Role of oxidative stress and thiol antioxidant enzymes in nickel toxicity and resistance in strains of the green alga Scenedesmus acutus f. alternans.

Treatment with Ni(NO3)2 leads to the formation of reactive oxygen species (ROS) in the green alga Scenedesmus acutus f. alternans, causing lipid peroxidation. This effect was stronger in a Ni-sensitive strain, UTEX72, than in a Ni-resistant strain, B4. In the resistant strain, Ni induced an increased ratio of reduced to oxidized glutathione (GSH:GSSG), whereas it caused a lowered ratio in the sensitive strain. Enzymes involved in the control of ROS were studied in these strains as well as two others that have shown different degrees of nickel resistance. The resistant strain, B4, which grows while containing large amounts of internal Ni, had much higher levels of glutathione reductase and catalase than the other strains. The sensitive strain, UTEX72, had higher levels of glutathione peroxidase, superoxide dismutase, and glucose-6-phosphate dehydrogenase than did strain B4. The resistant strains, Ni-Tol and Cu-Tol, derived from strain UTEX72, which are partly able to exclude Ni, had enzyme profiles that resembled that of UTEX72 more closely than that of B4. Treatment with 10 and 100 microM Ni for 4 or 22 h had complex effects on enzyme levels in all four strains. Ni decreased glutathione reductase in B4, slightly increased it in Ni-Tol and Cu-Tol, and did not affect the low levels of this enzyme in UTEX72. Ni lowered glutathione peroxidase in B4 and either did not affect it or slightly raised it in the other strains. Ni lowered catalase in B4 and did not affect the other strains. Superoxide dismutase was raised in B4 and Ni-Tol and lowered in Cu-Tol and UTEX72, and glucose-6-phosphate dehydrogenase was lowered in all four strains. These results suggest that one major mechanism of Ni resistance, especially in strain B4, may be the ability to combat the formation of ROS when exposed to this metal, likely by maintaining a high GSH:GSSG ratio.     

Use of resistant mutants to study the interaction of triton X-100 with Staphylococcus aureus.

Staphylococcus aureus mutants resistant to the nonionic detergent Triton X-100, isolated from the wild-type strain H and the autolysin-deficient strain RUS3, could grow and divide in broth containing 5% (vol/vol) Triton X-100, while growth of the parental strains was markedly inhibited above the critical micellar concentration (0.02%) of the detergent. Growth-inhibitory concentrations of Triton X-100 killed wild-type cells without demonstrable cellular lysis. Triton X-100 stimulated autolysin activity of S. aureus cells under nongrowing conditions, and this lytic response was markedly reduced in energy-poisoned cells. In contrast, the detergent had no effect on the activity of autolysins in cell-free systems, and growth in the presence of Triton X-100 did not alter either the cellular autolysin activity or the susceptibility of cell walls to exogenous lytic enzymes. Treatment with either Triton X-100 or penicillin G in the growth medium stimulated release of predominantly acylated intracellular lipoteichoic acid and sensitized staphylococci to Triton X-100-induced autolysis. There was no significant difference in the cell wall and membrane compositions or Triton X-100 binding between the parental strains and the resistant mutants. The resistant mutant TXR1, derived from S. aureus H, had a higher level of L-alpha-glycerophosphate dehydrogenase activity, and its oxygen uptake was more resistant to inhibition by a submicellar concentration (0.008%) of Triton X-100. Growth in the presence of subinhibitory concentrations of Triton X-100 rendered S. aureus H cells phenotypically resistant to the detergent and greatly stimulated the level of oxygen uptake. Membranes isolated from such cells exhibited enhanced activity of the respiratory enzymes succinic dehydrogenase and L-alpha-glycerophosphate dehydrogenase.     

Peroxidase and catalase activity in leaves of Halimione portulacoides exposed to salinity

The effect of high NaCl concentrations on the activity of catalase (EC 1.11.1.6), peroxidase (EC 1.11.1.7) and malate dehydrogenase (NAD⁺-linked; EC 1.1.1.37) from leaves of Halimione portulacoides (L.) Aellen was studied. The plants were exposed to high salinity during growth and enzyme activity was measured either in the absence or in the presence of various concentrations of NaCl. Increasing salinity in vitro induced three types of effects: (1) an increase in activity (peroxidase); (2) a decrease in activity (catalase); (3) stimulation by low salt concentration but inhibition by higher concentrations (malate dehydrogenase). Salinity in vivo induced a marked decrease in catalase and malate dehydrogenase activities. However, peroxidase in vivo showed an optimum curve of activity vs external NaCl concentration, with an optimum at ca 1 M NaCl. Exposure of plants to salinity induced changes in the properties of the enzyme proteins: they precipitated at a higher (NH₄)₂SO₄ concentration, were eluted later during Sephadex G-200 filtration, and showed a shift in the maximal, minimal and optimal temperatures. These data are interpreted as evidence for conformational changes in the enzymes due to prolonged exposure to high salinity stress; such changes could be disruption into monomers (catalase and malate dehydrogenase), or changes in molecular shape (in the peroxidase).     

Resistance of different strains of pathogenic staphylococcus to unfavorable environmental factors]

A study was made of the resistance to drying the UV-irradiation, the action of furacillin and chloramine displayed by 60 stains of S. aureus differing by origin (hospital and extrahospital), by the source of discharge (the upper respiratory tracts of carriers and the discharge of the purulent-inflammatory foci of surgical patients), relation to the antibiotics (polyresistant and sensitive) and phage-group reference. It was found that the resistance of staphylococci to the unfavourable factors was not always associated with the listed signs of the strains. In respect to drying a marked resistance was expressed by the hospital strains in comparison with the extrahospital ones, polyresistant in comparison with the sensitive ones, staphylococci of III and I+III phage groups in comparison with the strains of other bacteriophage groups. Strains of the III phage group proved to be the most resistant to the UV-irradiation. Strains isolated from carriers were more resistant to furacillin than staphylococci isolated from the purulent-inflammatory foci. Strains of the III phage group and nontyping had analogous advantages over the cultures of other phage groups.     

On the mechanism of action of tetracycline antibiotics

Oxytetracycline-sensitive and resistant strains of Staphylococci and ofListeria monocytogenes andPasteurella multocida were tested for differences in the reduction of triphenyltetrazolium (TTC) in the presence of glucose, acetate, lactate, pyruvate, glycerol, succinate, formate, malate, citrate, serine, glycine and asparagine. The sensitive staphylococci reduced TTC more actively than the resistant ones in the presence of glucose, acetate and serine. The resistant strains reduced TTC more actively in the presence of succinate, formate, glycine, pyruvate and malate. Oxytetracycline itself only inhibited the reducing activity greatly in the sensitive staphylococci. In the resistant ones, oxytetracycline only slightly decreased the TTC reduction. The insensitivity of the reducing activity of resistant staphylococci toward the effect of oxytetracycline indicates that this activity may be one of the sites of attack by this antibiotic. Ascorbic acid contained in the injection preparation of oxytetracycline interfered with the inhibitory effect of this antibiotic on the TTC reduction by staphylococci and actually increased the activity of reduction.     

Features of glycolysis and pentose phosphate pathway in novobiocin sensitive and novobiocin resistant staphylococci

Intensity of glycolysis and the pentose phosphate cycle in staphylococci sensitive and resistant to novobiocin was studied. The resistant variants did not practically store lactate and the activity of glycolytic enzymes i.e. hexokinase and aldolase was lowered by 15-20 and 53-59 per cent, respectively. Monoiodoacetate, a glycolysis inhibitor suppressed the glucose oxidation rate by 53.3-66.9 per cent in the sensitive variants and by 16-21.8 per cent in the resistant variants. At the same time it was characteristic of the resistant variants to increase the activity of the pentose phosphate cycle enzymes; glucose-6-phosphate dehydrogenase by 25-38.1 per cent transketolase by 21.5-27.3 per cent and transaldolase by 30-57.1 per cent. No differences in the transhydrogenase reaction kinetics of both the novobiocin sensitive and the novobiocin resistant variants were observed.     

Possible role of superoxide dismutases in the yeast Saccharomyces cerevisiae under respiratory conditions

We have analyzed the activity of antioxidant and tricarboxylic acid cycle enzymes as well as protein carbonyl content in budding yeast Saccharomyces cerevisiae cells grown in medium with glycerol using wild-strain cells and defective mutants in superoxide dismutases (SODs). The present report demonstrates that the activity of catalase, glucose-6-phosphate dehydrogenase, glutathione reductase, isocitrate dehydrogenase, succinate dehydrogenase, and malate dehydrogenase, on average, was lower in the strains lacking SODs than that in the parental strain. On the other hand, under conditions used in this study, the content of carbonyl groups in proteins was relatively higher in the wild type as compared with SOD-defective strains. It may be suggested that in vivo SOD can demonstrate protective as well as pro-oxidant properties, and the final result depends on particular conditions.     

Localisation and metabolism of reactive oxygen species during Bremia lactucae pathogenesis in Lactuca sativa and wild Lactuca spp.

A plant's physiology is modified simultaneously with Oomycete pathogen penetration, starting with release and accumulation of reactive oxygen species (ROS). Localisation of superoxide, hydrogen peroxide, peroxidase and variation in their activity, and the isoenzyme profile of antioxidant enzymes peroxidase (1.11.1.7), catalase (EC 1.11.1.6), superoxide dismutase (EC 1.15.1.1) were studied in six genotypes of four Lactuca spp. (L. sativa, L. serriola, L. saligna and L. virosa) challenged with Bremia lactucae (race NL16). These factors were related to the differential expression of resistance during the course of 96h after inoculation (hai). Accumulation of hydrogen peroxide in infected cells together with enhanced activity of H(2)O(2)-scavenging enzymes in leaf extracts characterised resistant Lactuca spp. genotypes 6-12hai, and peaked at 48-96hai with expression of a hypersensitive reaction. Substantial changes of guaiacol peroxidase activity were detected only in the cytosolic enzyme; activities of the membrane-bound and the ion-bound enzymes were insignificant in the interactions of host genotypes and pathogen isolate examined. The most significant modifications of ROS metabolism were found in resistant L. virosa (NVRS 10.001 602), a genotype responding to pathogen ingress by a rapid and extensive hypersensitive reaction. Formation of the superoxide anion was not detected in either susceptible or resistant plants, and there was also no increase of superoxide dismutase activity or changes in its isozyme profile. The significance of precise balancing the intracellular level of hydrogen peroxide for variability of phenotypic expression of responses to B. lactucae infection in Lactuca spp. is discussed.     

Isolation of peroxisomes from the dog kidney cortex.

The present study was undertaken to separate peroxisomes of the dog kidney cortex by the methods of discontinuous sucrose density gradient and zonal centrifugation. The separation of subcellular particles was evaluated by measuring the activities of reference enzymes, beta-glycerophosphatase for lysosomes, succinate dehydrogenase for mitochondria, glucose-6-phosphatase for microsomes, and catalase and D-amino acid oxidase for peroxisomes. The activities of D-amino acid oxidase and catalase were mainly observed in fractions 1 and 2 (1.6 and 1.7 M sucrose) obtained by discontinuous sucrose density-gradient centrifugation. Small amounts of acid phosphatase and succinate dehydrogenase contaminated these fractions. Considerably higher activity of catalase was determined in the supernatant, while D-amino acid oxidase showed a lower activity. By the method of zonal centrifugation, the highest specific activities of catalase and D-amino acid oxidase were found in fraction 50 (1.73 M sucrose) with no succinate dehydrogenase, acid phosphatase or glucose-6-phosphatase activity. These results suggested that peroxisomes of dog kidney cortex were clearly separated in 1.73 M sucrose from mitochondria, lysosomes and microsomes by zonal centrifugation.     

Lysis of bacterial protoplasts and spheroplasts and suppression of their dehydrogenase activity by neotehomycin]

Neotelomycin induced lysis of the protoplasts of Bac. megaterium and inhibited their succinate dehydrogenase activity. Direct correlation between the lytic activity of the antibiotic and its effect on succinate dehydrogenase was found. Neotelomycin had no effect on the dehydrogenase activity of the protoplast lysates. Possibly, suppression of the protoplast succinate dehydrogenase of Bac. megaterium under the effect of neotelomycin was due to significant structural changes caused by the antibiotic in the protoplast membranes and leading to their lysis and not to the direct effect on the enzyme. Neotelomycin had practically no effect on the spheroplast dehydrogenase activity of E. coli resistant to the antibiotic and did not induce their lysis. Resistance of E. coli to neotelomycin must be associated not with the presence of the antibiotic non-permeable cell wall but the peculiar properties of the membrane cytoplasm.     

Intrafibre distribution of succinate dehydrogenase in cat tibialis anterior motor units.

Using isolated ventral root filament stimulation and glycogen depletion techniques, 14 motor units from the cat tibialis anterior were studied. Based on their mechanical properties, the units were classified as either slow-fatigue resistant, fast-fatigue resistant, fast-fatigue intermediate, or fast-fatigable. Quantitative histochemical and computer assisted image analysis techniques were used to determine the activity of succinate dehydrogenase in a population of fibres in each unit. In addition, the intrafibre distribution of succinate dehydrogenase activity was measured in those same fibres by calculating the enzymatic activity of circumferential layers every 0.5 microns starting from the fibre edge to its centre. It was established that enzymatic activity and radial distance were linearly related in the fibres. A range in succinate dehydrogenase activity (mean coefficient of variation, 29%) was observed among the fibres of a unit. In contrast, the intrafibre distribution of that activity was rather consistent (mean variation, 4%) across the fibres of a unit. Further, the intrafibre distribution was similar among the fibres of units classified as the same type. However, the intrafibre distribution was disparate among the different unit types. These data suggest that the intrafibre distribution of mitochondrial enzymes may contribute to the mechanical properties of a motor unit. In this regard, a hypothesis is proposed that describes how the absolute activity of a mitochondrial enzyme, and the intrafibre distribution of that activity, may interactively contribute to the fatigue resistance of a unit.     

Studies on rat liver mitochondria: 4. Enzyme activities in mitochondria preserved at 0-4 degrees C

Rat liver mitochondria, stored with the energy-linked functions preserved or in aging conditions, were used to assay the activity of various enzymes during five days. The preservation of energy-linked functions was monitored by the respiratory control coefficient. ATPase, cytochrome oxidase and NADH dehydrogenase showed increased activity when the energy-linked functions were preserved. In aging conditions, cytochrome oxidase, NADH dehydrogenase and ATPase showed decreased activity. The ATPase activity increased only when mitochondria were stored in the presence of inhibitors of the electron transport chain. The activity of NADH oxidase did not change, and succinate oxidase and succinate dehydrogenase showed a small decrease in their activity. The enzymes of the matrix, alpha-ketoglutarate dehydrogenase, malate dehydrogenase and aspartate aminotransferase showed little decrease in activity under either of the conditions of storage. The total protein content decreased slightly under both conditions of storage. These results show that the activity of the enzymes analysed was maintained at reasonable levels, when the energy-linked functions of isolated mitochondria were preserved.     

Subcellular localization of oestrogen-induced uterine peroxidase.

The distribution of oestrogen-induced peroxidase in the resuspended 8000g pellet of rat uterine homogenates was examined by centrifugation in a sucrose density gradient. Within 10h of treatment with oestradiol, peroxidase activity was found in a region devoid of catalase or urate oxidase (peroxisomal markers) which did not overlap the fractions containing succinate dehydrogenase (mitochondrial marker) or acid phosphatase (lysosomal marker). The induced uterine enzyme was localized in reticular membrane-bound vesicles with isopycnic density of 1.28g/ml from which it could be released by treatment with detergent.     

Malate Dehydrogenase Mutants in Escherichia coli K-12

Mutants devoid of malate dehydrogenase activity have been isolated in Escherichia coli K-12. They do not possess detectable malate dehydrogenase when grown aerobically or anaerobically on glucose as sole carbon source. All mutants revert spontaneously; a few partial revertants have been found with a malate dehydrogenase exhibiting altered electrophoretic mobility. Therefore, only one such enzyme appears to exist in the strains examined. No evidence could be obtained for the presence of a malate dehydrogenase not linked to nicotinamide adenine dinucleotide. Mutants deficient in both malate dehydrogenase and phosphoenol pyruvate carboxylase activities will grow anaerobically on minimal glucose plus succinate medium; also, malate dehydrogenase mutants do not require succinate for anaerobic growth on glucose. The anaerobic pathway oxaloacetate to succinate or succinate to aspartate appears to be accomplished by aspartase. Malate dehydrogenase is coded for by a locus somewhere relatively near the histidine operon, i.e., a different chromosomal location than that known for other citric acid cycle enzymes.     

Some enzymes of general metabolism in the latex of Papaver somniferum

Enzymes of general metabolism have been determined in the latex of Papaver somniferum in an attempt to elucidate further the nature of the 1000 g130 min organelles and their role in alkaloid biogenesis. A number of enzymes involved in the glyoxylic acid and tricarboxylic acid cycles have been found, namely, aconitase, isocitrate dehydrogenase, succinate dehydrogenase, fumarase, malate dehydrogenase and isocitrate lyase. Two enzymes of glycolysis, namely, pyruvate kinase and lactate dehydrogenase, as well as enzymes associated with peroxisomes (glyoxylate reductase, catalase) and lysosomes (arylesterase, acid phosphatase) have been studied. Finally, some enzymes previously reported as occurring in poppy seedlings have been investigated, namely peroxidase, glutamate—oxaloacetate and glutamate-pyruvate transaminases, together with phenylalanine, tyrosine, DOPA and glutamic acid decarboxylases.     

Ascorbate-dependent hydrogen peroxide detoxification and ascorbate regeneration during germination of a highly productive maize hybrid: Evidence of an improved detoxification mechanism against reactive oxygen species

Ascorbate content and the activities of some key enzymes involved in the detoxification from reactive oxygen species were investigated in germinated embryos of two Zea mays L. inbred lines (B73 and Mo17) and of their heterotic F1 hybrid (B73×Mo17). The F1 hybrid showed a higher ascorbate biosynthetic capability owing to a higher activity of l -galactono- Γ -lactone dehydrogenase (EC 1.6.5.4), the last enzyme in ascorbate biosynthesis. Ascorbate peroxidase (EC 1.11.1.11), ascorbate free radical reductase (EC 1.6.5.4) and dehydroascorbate reductase (EC 1.8.5.1) activities were much higher in the F1 hybrid than in either inbred line, whereas catalase (EC 1.11.1.6) activity was similar in the three genotypes. Native polyacrylamide gel electrophoresis (PAGE) analysis showed three forms of cytosolic ascorbate peroxidase, both in parental lines and in the F1 hybrid. On the other hand, a complex pattern of proteins with dehydroascorbate reductase activity was observed, with the hybrid combining the different dehydroascorbate-reducing proteins expressed by the inbred lines. The possible involvement of the enzymes of the ascorbate system in the phenomenon of hybrid vigour is discussed.