3,4-dichloroaniline cometabolism by representatives of the genus Pseudomonas

The effect of propanide, linuron and 3,4-dichloroaniline on soil organisms was studied. Two strains of Pseudomonas aurantiaca 1 and 7, were isolated from soil; they decomposed propanide yielding 3,4-dichloroaniline. These strains, as well as a number of collection cultures belonging to the Pseudomonas genus, could transform 3,4-dichloroaniline at a rate of 0-100 per cent during 48 hours. A certain correlation existed between this transformation ability and the level of total oxidase activity. All the strains of Pseudomonas studied in this work were characterized by a low peroxidase activity, and no strict correlation was detected between its level and the ability to transform 3,4-dichloroaniline.     

Cholesterol esters in developing rat brain: enzymes of cholesterol ester metabolism

Abstract— Three enzymes of cholesterol ester metabolism, a cholesterol-esterifying enzyme which incorporates free fatty acids into cholesterol esters without participation of CoA, and two cholesterol ester hydrolases with differing pH optima, all showed distinct changes in developing rat brains. The specific activity of the esterifying enzyme was approx. 20 percent of the adult level at birth, increased gradually to the adult level by 20 days of age and remained constant thereafter. The pH 4.2 hydrolase at birth also had a specific activity of about 20 per cent of the adult level but it increased rapidly to reach a peak at 13 days, by which time the activity had increased eight-fold. The activity declined somewhat thereafter to reach the adult level by 23–30 days. In contrast, there already was 60 per cent of the adult specific activity of the pH 6.6 cholesterol ester hydrolase at birth. The activity remained constant until 12 days and then doubled during the next two weeks, reaching a broad peak, then declining slightly to reach the adult activity by 50 days. Therefore, the developmental changes of both of the hydrolases appeared to be related to the process of myelination. The period of active myelination (10–30 days) was characterized by the sharp rise in the activity of pH 6.6 cholesterol ester hydrolase and by the rapid decrease of pH 4.2 cholesterol ester hydrolase.     

Study of the effect of protoplast formation on the antibiotic activity of erythromycin producers

The influence of protoplasting and regeneration on the strains of the erythromycin-producing organism differing by their origin was studied with respect to changes in the antibiotic production property. 223 regenerates of the erythromycin-producing culture were tested in several generations and it was shown that there was a marked change in the range of the variation by that property. 40 to 70 per cent of the variants in the IInd generation increased their levels of erythromycin biosynthesis by 20 to 60 per cent as compared to the intact cultures. However, in the subcultures the antibiotic production level decreased and by the IVth generation only 3 to 6 per cent of the variants preserved its increase by 10 to 20 per cent over the control level because of the culture high instability.     

Changes in lipoprotein binding and uptake by hepatocytes during rat liver regeneration

The binding and uptake of cholesterol enriched lipoproteins by isolated hepatocytes was decreased at 16 hours after partial hepatectomy, with a tendency to return to control values as the regeneration proceeds. The number of lipoprotein binding sites of total cellular membranes remained similar to control at 16 and 24 hours. The plasma lipoprotein pattern, determined by electrophoretic analysis, showed a lower per cent of very low density lipoproteins (VLDL) and a higher per cent of low density lipoproteins (LDL) at 16 and 24 hours post-partial hepatectomy. At these times, plasma lecithin: cholesterol acyltransferase (LCAT) activity was decreased. It is intriguing to suggest that the regenerating liver could regulated the blood lipoprotein pattern and the uptake of lipoproteins by modulating the surface expression of the receptors.     

Auxotrophic mutants of the producer of the antibiotic mycoheptin Streptoverticillium mycoheptinicum

The lethal and mutagenic effects of N-nitrozo-N-methyl biuret (NMB), N-nitrozo-N-methyl urea (NMU) and UV light on Streptoverticillium mycoheptinicum, strains O883 and 852, were studied. The concentrations of NMB were 0.005, 0.1 and 0.25 per cent, the exposure time was 2, 4 and 6 hours. The concentration of NMU was 1 per cent and the exposure time was 1, 2, 3, 4 and 5 hours. The dose of UV light was 2000 erg/mm2. When the spores of Streptoverticillium mycoheptinicum, strain O883, were treated with NMB, the frequency of auxotrophic mutants increased from 0.63 to 3.4 per cent with an increase of the mutagen concentration from 0.05 to 0.25 per cent and the exposure time from 2 to 6 hours. More than 80 auxotrophic mutants were selected. When Streptoverticillium mycoheptinicum, strain 852, was treated with NMU, the frequency of auxotrophic mutants ranged from 0.5 to 2.4 per cent. Fifty-seven auxotrophic mutants were selected. The majority of the auxotrophic mutants selected with the use of NMB and NMU was unstable. Exposure of Streptoverticillium mycoheptinicum, strains 852, 10/69 Met and 54/100 Lys to UV light resulted in formation of groups of polyauxotrophic mutants.     

Action of polyene antibiotics on actinomycetes with a varying lipid makeup]

The effect of polyenic antibiotics, such as nystatin, levorin, amphotericin B and mycoheptin on 93 representatives of various species of the ray fungi was studied. It was shown that resistance of the actinomycetes to the polyens was connected with the absence or insufficient content of sterols (0.001--0.008 per cent in the dry mycelium). On addition of cholesterol to the nutrient media (100 microgram/ml) it was included into the membranes of some cultures and their sensitivity increased 2--60 times. Resistance of Actinomyces sp. LIA 0775 grown on the media with fats differing in their composition decreased 2--4 times. In these cases the culture lipids were characterized by lower content of phospholipids (35--45 per cent from the total lipids as compared to 70--80 per cent when grown on the control medium without fats) and significantly increased content of unsaturated fatty acids (3--4 times).     

Effect of tricyclohexylhydroxytin on synaptosomal Ca2+-dependent ATP hydrolysis and rat brain subcellular calmodulin

Effect of tricyclohexylhydroxytin (plictran) on Ca2+-ATPase activity was studied in rat brain synaptosomes under in vitro and in vivo conditions. Plictran inhibited basal Ca2+-ATPase activity with an IC50 value of 6 nM suggesting its interaction with calcium transport phenomenon. Plictran inhibited calmodulin (CaM) activated Ca2+-ATPase in a concentration-dependent manner. A complete reversal of calmodulin activation of Ca2+-ATPase was observed with 2-3 nM plictran. A 50 per cent decrease of CaM activated Ca2+-ATPase was observed with 0.5 nM plictran, a concentration at which no significant effect was observed on basal enzyme activity. Of all the brain fractions studied, calmodulin levels in P2 fractions alone were reduced significantly to about 75 per cent of control values in plictran treated rats. The synaptosomal Ca2+-ATPase was also decreased by 35 per cent, 42 per cent and 65 per cent in 10, 20 and 40 mg plictran kg-1 day-1 treated rats for 3 days respectively. The activity levels of Ca2+-ATPase in 10 and 20 mg plictran kg-1 day-1 treated rats were restored to normal level by exogenously added calmodulin. These results suggest that plictran may disrupt synaptic function by altering calcium and calmodulin regulated processes in the central nervous system.     

Growth and development of extreme-thermophilic bacteria at 70 degrees]

Nine cultures of non-sporeforming gram-negative extreme-thermophilic bacterium Thermus flavus have been isolated from hot springs of Kamchatka. Their optimal growth temperature on a solid potato medium was 70 to 76 degrees C, and on a liquid medium (20 per cent potato broth containing 0.5 per cent peptone and 0.1 per cent yeast extract) 70 degrees C. The minimum time of generation of the bacterium, strain 71, growing on the liquid medium at 70 degrees C, was 52 minutes. Other extreme-thermophilic cultures differ from the strain 71 by a lower growth rate. The maximum biomass yield was 1.96 g per litre of the medium after 6 to 9 hours of growth. The extreme-thermophilic bacteria of Kamchatka are similar to those from the hot springs of Japan.     

Antibiotic sensitivity and pathogenetic factors of hospital strains of Pseudomonas aeruginosa isolated from patients treated in a resuscitation unit]

Strains of Pseudomonas aeruginosa were isolated from patients treated in the Centre of Thermal Affections in 1985-1989. It was shown that 72.9, 59.3, 33.8 and 54.2 per cent of the isolates were sensitive to cefotaxime, tobramycin, gentamicin and polymyxin, respectively. The study of pathogenicity factors of the isolates revealed that 83 per cent of the strains produced thermolabile enterotoxin, 79.6 per cent of the strains had adhesive activity and 71.1 per cent of the strains produced hemolysin. The study detected combinations of various pathogenicity factors. 42.3 per cent of the isolates had both adhesive and enterotoxigenic properties. Adhesiveness and hemolytic activity were shown by 13.5 per cent of the strains. 16.9 per cent of the strains produced both enterotoxin and hemolysin. Adhesive activity, enterotoxigenicity and hemolysin production were observed in 6.7 per cent of the strains. It was noted that the strains of P. aeruginosa resistant to polymyxin mainly produced enterotoxin (18.6 per cent) and those resistant to cefotaxime had adhesive activity (34.0 per cent).     

Colorimetric analysis with N,N-dimethyl-p-phenylenediamine of the uptake of intravenously injected horseradish peroxidase by various tissues of the rat

1. A method is described for the colorimetric determination of peroxidase with N,N-dimethyl-p-phenylenediamine. The amount of red pigment formed by peroxidase is proportional to the concentration of enzyme and to the time of incubation during the first 40 to 90 seconds. The influence of the concentration of enzyme, N,N-dimethyl-p-phenylenediamine, H(2)O(2), the time of incubation, pH, the temperature, and the possible interference by oxidizing and reducing agents of tissues has been tested. 2. The method has been used to follow the uptake of intravenously injected horseradish peroxidase by 18 different tissues of the rat over a period of 30 hours. The highest concentration of the injected tracer enzyme was found in extracts of kidney, liver, bone marrow, thymus, and spleen. Considerable amounts were taken up by pancreas, prostate, epididymis, and small intestine. Lower concentrations were found in extracts of lung, stomach, heart, and skeletal muscle, aorta, skin, and connective tissue. No uptake was observed by brain and peripheral nerve tissue. 3. Tissue homogenates containing high concentrations of the injected peroxidase, in general also showed high or average activity of acid phosphatase. 4. Six hours after intravenous administration, the liver contained 27 per cent, the kidney 12 per cent, and the spleen, 1.4 per cent of the injected dose. 5. Approximately 20 per cent of the injected peroxidase was excreted in the urine during the first 6 hours, and the concentration of peroxidase in blood serum and urine fell exponentially during this time. After 6 hours, only low concentrations were excreted in the urine but low enzyme activity was still detectable after 30 hours. Approximately 6 per cent of the injected dose was excreted in the feces from 6 to 20 hours after administration. 6. After feeding through a stomach tube, low concentrations of peroxidase were found in blood serum and urine. Considerable variations in the extent of absorption from the gastrointestinal tract were observed in individual rats.     

The comparative activity of cefepime and other current antibiotics against microorganisms isolated from patients in pediatric intensive therapy units]

Comparative activity of cefepime, ceftazidime, ceftriaxone, ciprofloxacin, imipenem and piperacillin/tazobactam against isolates from patients of pediatric intensive care units within October-December 1998 was studied. The isolates were identified with the Walkaway-40 System. The antibiotic susceptibility was evaluated by the E-test on the Mueller-Hinton II agar. The data were interpreted in accordance with the NCCLS. The number of the isolates totaled 100. Among them not more than 10 to 12 strains belonged to the same species. 92 per cent of the isolates was susceptible to cefepime and 70 to 75 per cent of the isolates were susceptible to the third generation cephalosporins. Piperacillin/tazobactam proved to be highly susceptible, the number of the isolates resistant and moderately resistant to it being 6 and 1 per cent respectively. The results showed that cefepime was intermediate between the third generation cephalosporins and carbapenems.     

In Vitro Antimicrobial Activity and Human Pharmacology of Cephaloglycin

Serum and urine concentrations of cephaloglycin (an orally absorbed derivative of cephalosporin C) were determined in normal volunteers and in patients. The in vitro activity of cephaloglycin was also studied. All strains of group A streptococci (Streptococcus pyogenes) and Diplococcus pneumoniae were inhibited by 0.4 mug of cephaloglycin per ml. Eighty per cent of the Staphylococcus aureus strains and about 50% of the Escherichia coli and Proteus mirabilis strains were inhibited by 1.6 mug of cephaloglycin per ml. Klebsiella-Aerobacter species were more resistant to cephaloglycin and 12.5 mug per ml was required to inhibit 70% of these strains. When single doses of 250, 500, or 1,000 mg of cephaloglycin were administered to fasting volunteers, a peak serum concentration of at least 0.5 mug per ml was achieved. A full breakfast did not interfere with absorption of cephaloglycin. Probenecid enhanced both the peak serum concentration and the duration of antibiotic activity in the serum. Serum concentrations of cephaloglycin were even higher in patients who were receiving repeated doses. The peak serum concentrations of cephaloglycin in all volunteers and patients were adequate to inhibit all strains of group A streptococci and D. pneumoniae. Many of the peak serum concentrations were adequate to inhibit some strains of S. aureus, E. coli, and P. mirabilis. Urine levels of cephaloglycin were high enough in all volunteers and patients to inhibit more than 90% of the E. coli and P. mirabilis strains and over 70% of the strains of Klebsiella-Aerobacter.     

Efficacy of meropenem in the treatment of severe complicated urinary tract infections]

The clinical and bacteriological efficacies of meropenem in the treatment of 12 patients with urinary tract infection were studied. In 8 patients the drug was administered intravenously in a dose of 1 g every 8 hours and in 4 patients with the creatinine clearance below 50 ml/min it was administered in a dose of 1 g every 12 hours (the treatment course of 7 to 10 days). Meropenem was used in the monotherapy. Severe complicated urinary tract infections were mainly observed in the patients with long-term urolithiasis, subjected to repeated surgical interventions and isolating as a rule polyresistant strains of Pseudomonas aeruginosa and E.agglomerans as the pyelonephritis pathogens at a titre of 5 x 10(5)-5 x 10(8) microbial cells per 1 ml of the urine susceptible to meropenem in 80 to 96 per cent of the cases. The clinical efficacy of the drug was stated in all the patients while the bacteriological efficacy amounted to 88.9 per cent.     

产胞外邻苯二酚1.2—双加氧酶的菌种筛选和发酵条件的研究

Two strains of Pseudomonus sp. having the extracellular catechol 1, 2-dioxygenase activity were selected from 112 bacterial strains. The conditions for enzyme production of the strains were examined. The optimal temperature and pH for enzyme formation were 30 degrees C and pH 6.8-7.0 respectively. Enzyme formation was enhanced by sodium benzoate, and was markedly inhibited by glucose, maltose and glycerol. Ammoniacal nitrogen sources were essential for cell growth and enzyme production. Sodium succinate was an effective inducer for enzyme formation. When the organism was grown in 0.15% sodium benzoate medium (pH 6.8-7.0) at 30 degrees C for 72 hours, about 10 units of catechol 1,2 dioxygenase per ml was obtained.     

Methodological procedures for detecting antibiotic producers among cultures of the family Micromonosporaceae]

Data on intensification of the search for active cultures among Micromonospora are presented. It was shown that the frequency of detecting the antibiotic-producing cultures among Micromonospora under conditions of fermentation on the corn-glucose medium inoculated with agar blocks amounted to 35 per cent. The use of nutrient media of different composition for growing submerged inoculum of Micromonospora demonstrated that the rate of its growth reached maximum on the peastarch medium. The use of this medium for growing submerged seed material for fermentation in the corn-glucose medium increased the frequency of detecting active cultures from 35 to 43.1 per cent. The assay of Micromonospora antibiotic activity twice, i.e. in 96 and 240 hours of the fermentation process increased the frequency of detecting active cultures up to 57.1 per cent and revealing greater variety of antibiotics. Fermentation of Micromonospora cultures simultaneously on 6 different nutrient media inoculated with submerged seed mycelium and assay of the activity for 2 times, i. e. in 96 and 240 hours allowed a detection of up to 76.2 per cent of active strains out of the total number of the isolates.     

ISOLATION OF AN INSULIN SECRETION GRANULE FRACTION

Goosefish islets were homogenized in 0.25 M sucrose and separated into nuclear, mitochondrial + secretion granule, microsomal, and supernatant fractions. Eighty per cent of the cytochrome oxidase activity and 75 per cent of the bioassayed insulin activity were found in the mitochondrial + secretion granule fraction (6000 g for 10 minutes). The mitochondrial + secretion granule fraction was further subfractionated by centrifugation (2 hours at 100,000 g and 0°C) using a continuous linear density gradient 1.0–2.0 M sucrose). Eighteen to 20 subfractions were collected by piercing the bottom of the tube and collecting drops. The total protein was distributed into a bimodal curve consisting of a high density component, which contained 90 per cent of the insulin (secretion granules), and a lower density component, which contained the cytochrome oxidase activity (mitochondria).     

Lysis of the cellular walls of Streptococcus group A by enzymes produced by actinomycetes]

More than 80 cultures of actinomycetes belonging to different taxanomic groups were studied with a purpose of screening actinomycetes actively producing enzymes lyzing the cell walls of group A streptococci. 31 strains of the actinomycetes producing enzymes which lyzed the cell walls by 20-50 and 60-80 per cent within 1 and 4 hours respectively were selected. The proteolytic activity of the enzymes produced by these strains was also studied. It was shown that 4 cultures, i.e. Actinomyces albus, strains 6 and 9, Actinomyces levoris, strain 29 and Actinomyces gibsonii, strain 42 were of interest as organisms producing enzymes which lyzed the streptococcal cell wall without impairing its antigenic components.     

Effect of dietary fat on lymphocyte proliferation and metabolism

The effect of diets enriched with fat containing different fatty acids on glucose and glutamine metabolism of mesenteric lymph nodes lymphocytes, spleen, and thymus and lymphocyte proliferation was examined. The following fat-rich diets were tested: (1) standard chow (CC); (2) medium chain saturated fatty acids (MS)—coconut fat oil; (3) long chain saturated fatty acids (LS)—cocoa butter; (4) monounsaturated fatty acids (MU)—canola oil (n-9); (5) polyunsaturated fatty acids (PU)—soybean oil (n-6). Of the fat-rich diets tested, MS was the one to present the least pronounced effect. Lymphocyte proliferation was reduced by LS (64 per cent), MU (55 per cent), and PU (60 per cent). Hexokinase activity was enhanced in lymph node lymphocytes by PU (67 per cent), in the spleen by MS (42 per cent), and in the thymus by PU (30 per cent). This enzyme activity was reduced in the spleen (33 per cent) by LS and MU (35 per cent). In the thymus, this enzyme activity was reduced by LS (26 per cent) and MU (13 per cent). Maximal phosphate-dependent glutaminase activity was raised in lymphocytes by MS (70 per cent) and MU (20 per cent). This enzyme activity, however, was decreased in lymphocytes by PU (26 per cent), in the spleen by LS (15 per cent), and in the thymus by MU (44 per cent). Citrate synthase activity was increased in lymphocytes by MU (35 per cent), in the spleen by LS (56 per cent) and MU (68 per cent), and in the thymus by LS (42 per cent). This enzyme activity was decreased in lymphocytes by PU (24 per cent) only. [U-¹⁴C]-Glucose decarboxylation was raised by all fat-rich diets; MS (88 per cent), LS (39 per cent), MU (33 per cent), and PU (50 per cent), whereas [U-¹⁴C]-glutamine decarboxylation was increased by LS (53 per cent) and MU (55 per cent) and decreased by MS (17 per cent). The results presented indicate that the reduction in lymphocyte proliferation due to LS, LU and PU could well be a consequence of changes in glucose and glutamine metabolism. Copyright © 1998 John Wiley & Sons, Ltd.     

Decreased repair of gamma-irradiated adenovirus in Xeroderma pigmentosum fibroblasts.

The ability of gamma-irradiated adenovirus to produce viral structural antigens (Vag) was examined in several normal and Xeroderma pigmentosum (XP) fibroblast strains. The fibroblast cultures were infected with either irradiated or nonirradiated adenovirus and at 48 hours after infection, cells were examined for the presence of Vag using immunofluorescent staining. Survival of Vag synthesis for gamma-irradiated adenovirus had a D37 value of 47 +/- 4 x 10(4) rad following the infection of seven normal fibroblast strains. The survival of this viral function was found to be significantly less following infection of the XP strains. D37 values for Vag synthesis expressed as a percentage of that obtained on normal strains were obtained for a representative strain from each of the XP complementation groups: group A, 57 per cent; group B, 61 per cent; group C, 61 per cent, group D, 59 per cent; group E, 73 per cent; and variant, 75 per cent. These results indicate that XP cells have a reduced repair capacity for some type of gamma-ray-induced DNA damage.     

CRYSTALLIZATION OF PEPSIN FROM ALCOHOL

1. Pepsin is soluble in 65 per cent alcohol and may be readily crystallized from 20 per cent alcohol. The crystals appear as needles or plates which may be transformed into the usual hexagonal bipyramids by recrystallization from water. The different crystals are probably two crystalline forms of the same chemical substance. 2. The enzyme is quite stable in 20 per cent alcohol at pH 2.0 but is inactivated by high concentrations of alcohol. 3. The enzyme is stable for several hours in 65 per cent alcohol at pH 4.0 to 5.0 but is rapidly inactivated in more acid solution. 4. No increase in activity could be noted after treatment with hydrogen peroxide. 5. No proteolytic activity either before or after treatment with hydrogen peroxide could be found in trichloracetic acid filtrates, butyl alcohol extracts of pepsin preparations, or oxidized phenylhydrazine solutions.