Effect of glutamate on the degradation of pentachlorophenol by Flavobacterium sp.

Summary The degradation of pentachlorophenol (PCP) by a Flavobacterium sp. was investigated by inoculating induced cells into cultures containing PCP alone or PCP and glutamate as carbon sources. Using PCP as the sole carbon source, the degradation activity increased with PCP concentration. However, a lag phase was observed and this lag was more pronounced at higher PCP concentrations. Exposure of cells to higher PCP concentrations during induction did not reduce the lag. The presence of glutamate reduced the lag in PCP degradation. Such an elimination of the lag phase appears to be due to maintaining cell viability with the presence of glutamate. Offprint requests to: W.-S. Hu     

Degradation of pentachlorophenol by a Flavobacterium species grown in continuous culture under various nutrient limitations.

A Flavobacterium sp. was grown in continuous culture limited for growth with ammonium, phosphate, sulfate, glucose, glucose + pentachlorophenol (PCP) (0.065 h -1), or PCP. Cells ere harvested, washed, and suspended to 3 x 10(7) cells ml (-1) in shake flasks containing a complete mineral salts medium without added carbon or supplemented with 50 mg of PCP ml(-1) or 50 mg of PCP ml(-1) + 100 mg of glucose ml(-1). The PCP concentration and the viable cell density were determined periodically. Cells that were grown under phosphate, glucose, or glucose + PCP limitation were more sensitive to PCP and took longer to degrade 50 mg of PCP ml(-1) than did cells that very were grown under ammonium, sulfate, or PCP limitation. Glucose stimulated viability and PCP degradation in all cases except when the cells were grown under carbon limitation with glucose and PCP added together as the carbon source. These results indicate that there is a relationship between nutrient limitation, phenotypic variation, and the sensitivity to and degradation of PCP by this organism.     

Cytotoxic effects of pentachlorophenol (PCP) and its metabolite tetrachlorohydroquinone (TCHQ) on liver cells are modulated by antioxidants

The worldwide distribution and high bioaccumulation potential of pentachlorophenol (PCP) in aquatic organisms imply a high toxicological impact in aquatic systems. Firstly, our investigations show that, similar to mammalian cell lines, PCP can be metabolized to tetrachlorohydroquinone (TCHQ) in the permanent cell line derived from rainbow trout liver cells (RTL-W1). Moreover, we demonstrate that PCP as well as its metabolite TCHQ is capable of influencing the viability of these cells. Three cell viability assays were performed to assess possible cellular targets of these substances. Thus, the cytotoxicity of the PCP-derivative TCHQ was shown for the first time in a fish cell line. Further investigations revealed the involvement of ROS in the cytotoxicity of PCP and its metabolite TCHQ. The observation of oxidative stress provides a plausible explanation for the increased cytotoxicity at higher concentrations especially for PCP and implies possible mechanisms underlying these observations. In addition, antioxidants such as ascorbic acid and quercetin modulate the detrimental effects of PCP and TCHQ whereby both compounds exacerbate the cytotoxic effects of high PCP and TCHQ concentrations.     

Influence of readily metabolizable carbon on pentachlorophenol metabolism by a pentachlorophenol-degrading Flavobacterium sp.

The influence of high concentrations of pentachlorophenol (PCP) and readily metabolizable carbon on the activity and viability of a PCP-degrading Flavobacterium sp. was examined in a mineral salts medium. Lags preceding PCP removal by glutamate-grown Flavobacterium cells were greatly attenuated by the addition of glutamate, aspartate, succinate, acetate, glucose, or cellobiose. The effect of these supplementary carbon sources on the apparent lag was not mediated entirely through the stimulation of growth since PCP metabolism accompanied the onset of growth. The specific activity of PCP-degrading cells in the absence of supplementary carbon was 1.51 x 10(-13) +/- 0.08 x 10(-13) g of PCP per cell per h and in the presence of supplementary carbon was 0.92 x 10(-13) +/- 0.09 x 10(-13) g of PCP per cell per h. Glutamate in combination with glucose or cellobiose partially repressed PCP metabolism. PCP removal by PCP-induced, glutamate-grown cells suspended in the presence of 4 g of sodium glutamate per liter was sensitive to shock loads of PCP, with a Ki of about 86.8 micrograms/ml. Subsequent removal rates, however, were more resistant to PCP. Optimal stimulation of PCP removal by sodium glutamate required 3.0 g/liter, about the same concentration as that which saturated growth in the absence of PCP. PCP removal rates decayed within minutes following the transfer of PCP-induced, glutamate-grown cells to media containing PCP without supplementary carbon, and increasing PCP concentrations accelerated the decay.(ABSTRACT TRUNCATED AT 250 WORDS)     

Generalized immune response to Pneumocystis carinii infection in the lung.

We studied inflammatory cells retrieved by bronchoalveolar lavage (BAL) from immunocompromised patients with or without Pneumocystis carinii pneumonia (PCP). Twenty-four patients with PCP, and 20 patients without PCP underwent lavages of both an uninvolved lobe and the lobe involved in pulmonary infection. Patients without P. carinii, had a significant increase (p less than 0.02) in the percentages of neutrophils (22 +/- 7.1%, mean +/- SEM) and lymphocytes (16 +/- 3.8%) in the involved lobe compared to those in the uninvolved area (neutrophils: 9 +/- 4.8%; lymphocytes: 10 +/- 2.4%). Patients with PCP, had no differences between the % neutrophils or % lymphocytes in the involved vs. uninvolved lobes. Patients with PCP had more (p less than 0.01) P. carinii in the upper lobe (23 +/- 4.6 P. carinii clusters/500 cells) than the middle lobe (11 +/- 3.6). In PCP, despite regional infections, there was a diffuse inflammatory response.     

四川地区阴道毛滴虫内人型支原体的PCR检测

从临床上分离获得20株阴道毛滴虫虫株,经纯化培养后,提取基因组DNA.以人型支原体16S rDNA序列设计特异性引物,利用PCR技术检测阴道毛滴虫内的人型支原体,结果有13株为人型支原体阳性,感染率为65%,表明阴道毛滴虫与人型支原体的共生关系在中国四川具有普遍性.     

Degradation of pentachlorophenol by a Flavobacterium species grown in continuous culture under various nutrient limitations

A Flavobacterium sp. was grown in continuous culture limited for growth with ammonium, phosphate, sulfate, glucose, glucose + pentachlorophenol (PCP) (0.065 h -1), or PCP. Cells ere harvested, washed, and suspended to 3 x 10(7) cells ml (-1) in shake flasks containing a complete mineral salts medium without added carbon or supplemented with 50 mg of PCP ml(-1) or 50 mg of PCP ml(-1) + 100 mg of glucose ml(-1). The PCP concentration and the viable cell density were determined periodically. Cells that were grown under phosphate, glucose, or glucose + PCP limitation were more sensitive to PCP and took longer to degrade 50 mg of PCP ml(-1) than did cells that very were grown under ammonium, sulfate, or PCP limitation. Glucose stimulated viability and PCP degradation in all cases except when the cells were grown under carbon limitation with glucose and PCP added together as the carbon source. These results indicate that there is a relationship between nutrient limitation, phenotypic variation, and the sensitivity to and degradation of PCP by this organism.     

Mycoplasma hominis septicaemia.

Mycoplasma hominis septicaemia occurred in a patient with a malignant lymphoma of lymphoblastic type in leukaemic phase. M hominis was isolated several times from blood cultures with antibody titres against the micro-organism rising to a high level despite severe immunosuppression. M hominis was detected in the blood after subculture of the blood culture bottles despite their macroscopically normal appearance. The patient''s pyrexia resolved without treatment with antibiotics effective against M hominis.     

Blastocystis hominis: frequency of infection in ambulatory patients from the northern section of Santiago, Chile]

In July 1989-July 1990 period, a coproparasitological study of 6,162 ambulatory patients from the northern section of Santiago, was undertaken. Out of the total number of the studied individual, 88.6% were children, (51.4% females and 48.6% males). The global frequency of infection by B. hominis was 30.4%. In relation to age. Blastocystis hominis was found in: 13.1% of the group of children (1 month-2 years); 34.1% of the pre-school children, 45.4% in the school-children and 43.0% in the adults. B. hominis was frequently detected in association with other parasites and/or commensals, and observed alone in the 6.0% of the studied patients.     

Blastocystis hominis--a potential intestinal pathogen.

The parasite Blastocystis hominis has been found in 10% to 18% of stool specimens submitted to microbiology laboratories. Controversy exists as to whether this organism can cause illness in humans. We have reviewed the records of 65 symptomatic patients with B hominis in their stool. We conclude that B hominis is a potential pathogen that may or may not require drug therapy depending on the overall clinical circumstances, the severity of symptoms, and the presence of other pathogenic organisms.     

Influence of readily metabolizable carbon on pentachlorophenol metabolism by a pentachlorophenol-degrading Flavobacterium sp

The influence of high concentrations of pentachlorophenol (PCP) and readily metabolizable carbon on the activity and viability of a PCP-degrading Flavobacterium sp. was examined in a mineral salts medium. Lags preceding PCP removal by glutamate-grown Flavobacterium cells were greatly attenuated by the addition of glutamate, aspartate, succinate, acetate, glucose, or cellobiose. The effect of these supplementary carbon sources on the apparent lag was not mediated entirely through the stimulation of growth since PCP metabolism accompanied the onset of growth. The specific activity of PCP-degrading cells in the absence of supplementary carbon was 1.51 x 10(-13) +/- 0.08 x 10(-13) g of PCP per cell per h and in the presence of supplementary carbon was 0.92 x 10(-13) +/- 0.09 x 10(-13) g of PCP per cell per h. Glutamate in combination with glucose or cellobiose partially repressed PCP metabolism. PCP removal by PCP-induced, glutamate-grown cells suspended in the presence of 4 g of sodium glutamate per liter was sensitive to shock loads of PCP, with a Ki of about 86.8 micrograms/ml. Subsequent removal rates, however, were more resistant to PCP. Optimal stimulation of PCP removal by sodium glutamate required 3.0 g/liter, about the same concentration as that which saturated growth in the absence of PCP. PCP removal rates decayed within minutes following the transfer of PCP-induced, glutamate-grown cells to media containing PCP without supplementary carbon, and increasing PCP concentrations accelerated the decay.(ABSTRACT TRUNCATED AT 250 WORDS)     

Open-label efficacy and safety trial of 42 days of 566C80 for Pneumocystis carinii pneumonia in AIDS patients.

Pneumocystis carinii pneumonia continues to be a cause of morbidity and mortality in AIDS patients. Current therapies have a high rate of toxicity and failure. Compound 566C80 is a 1-4,hydroxynaphthoquinone with potent antiprotozoal activity which shows good efficacy and safety in 21-day treatment trials of P. carinii pneumonia (PCP) in AIDS patients. Because there is a generally high recurrence rate after treatment of PCP and there may be a possible advantage in decreasing the P. carinii burden in the lung with extended anti-Pneumocystis therapy, we performed an open label-trial of the safety and efficacy of 42-day therapy with 566C80 for PCP in AIDS patients. Ten patients were enrolled and one was lost to follow-up. Eight of the remaining nine patients successfully completed 42 days of therapy with minimal toxicity. This trial suggests that 566C80 for 42 days can be an effective, safe, and well-tolerated oral therapy for PCP in AIDS patients.     

Ultrastructure of Blastocystis hominis in human stool samples.

A study of the ultrastructure of Blastocystis hominis in human stools found morphological differences between the organisms seen and those present in laboratory cultures. B. hominis found in stool samples showed little morphological variation with storage time before fixation, but were consistently smaller (approximately 5 microns in diameter), with a thicker surface coat than the cultured organisms. The large central vacuole, characteristic of the cultured organisms, and accepted as standard morphology of B. hominis, was rarely observed in organisms present in stool samples. Instead, a number of small vacuoles, or possibly a network of interconnected vacuoles, were noted. After short-term culture, organisms from these samples appeared with the typical vacuolated morphology. No large vacuoles were present in organisms obtained at colonoscopy. These results suggest that the vacuolated form as previously described may be an artefact of culture conditions, and that the form of B. hominis present in the gastrointestinal tract is avacuolar.     

Characterization of a novel Pseudomonas sp. that mineralizes high concentrations of pentachlorophenol.

A pentachlorophenol (PCP)-mineralizing bacterium was isolated from polluted soil and identified as Pseudomonas sp. strain RA2. In batch cultures, Pseudomonas sp. strain RA2 used PCP as its sole source of carbon and energy and was capable of completely degrading this compound as indicated by radiotracer studies, stoichiometric release of chloride, and biomass formation. Pseudomonas sp. strain RA2 was able to mineralize a higher concentration of PCP (160 mg liter-1) than any previously reported PCP-degrading pseudomonad. At a PCP concentration of 200 mg liter-1, cell growth was completely inhibited and PCP was not degraded, although an active population of Pseudomonas sp. RA2 was still present in these cultures after 2 weeks. The inhibitory effect of PCP was partially attributable to its effect on the growth rate of Pseudomonas sp. strain RA2. The highest specific growth rate (mu = 0.09 h-1) was reached at a PCP concentration of 40 mg liter-1 but decreased at higher or lower PCP concentrations, with the lowest mu (0.05 h-1) occurring at 150 mg liter-1. Despite this reduction in growth rate, total biomass production was proportional to PCP concentration at all PCP concentrations degraded by Pseudomonas sp. RA2. In contrast, final cell density was reduced to below expected values at PCP concentrations greater than 100 mg liter-1. These results indicate that, in addition to its effect as an uncoupler of oxidative phosphorylation, PCP may also inhibit cell division in Pseudomonas sp. strain RA2.(ABSTRACT TRUNCATED AT 250 WORDS)     

Blastocystis hominis in patients at the Ruiz y Paez University Hospital from Bolivar City, Venezuela]

Blastocystis hominis is a polymorphic protozoan of discussed taxonomic position, which is currently associated with human intestinal disease. In order to determine the prevalence of the microorganism in a sample of hospitalized patients, a study was carried out from november 1996 to april 1997 on 100 adult patients of both sexes aged 20 to 79 years at the "Ruíz y Páez" University Hospital of Bolivar city, Venezuela. A coproparasitological study was carried out using direct examination and Faust method. Infection by parasites and/or commensals was demonstrated in 48 patients. The most frequent agent was B. hominis with a prevalence of 42.0%. We did not find a statistically association between sex (P > 0.05) or age (X2 = 3.52; d.f; = 3) and B. hominis infection. B. hominis was most frequently identified as the single parasite (88.1%), and with a number of less than 5 cells per 400X microscopic field (73.8%). The infection was more common in patients with base chronic-immunosuppressive diseases, the major one being cancer. Diarrhea was observed in 27.0% of cases. Due to its high prevalence, especially as a single agent, together with the particular immunological characteristics of the patients studied, a potential pathogenic role of the opportunistic type is suggested for B. hominis.     

Immunological studies on the localization of phosphatidylglycerol in the membranes of Mycoplasma hominis.

Phosphatidylglycerol is the main component (87%) of the membrane phospholipids of Mycoplasma hominis. It is immunologically active. Antibodies directed against phosphatidylglycerol were detected in rabbits intravenously immunised with native M. hominis or isolated M. hominis membranes. The intravenous method of immunisation was chosen in order to select for a response to surface antigenic determinants. Anti-phosphatidylglycerol antibodies were induced in rabbits by intravenously injecting the flocculated complexes of methylated bovine serum albumin and a phosphatidylglycerol/phosphatidylcholine/cholesterol mixture. These antibodies were specifically bound to intact M. hominis, as shown by complement fixation and Coombs tests. Native M. hominis were not agglutinated by anti-phosphatidylglycerol antibodies; but after partial digestion of the membrane proteins with Pronase, the mycoplasmas were heavily agglutinated by the anti-phosphatidylglycerol antibodies. The same amount of anti-phosphatidylglycerol antibodies was bound to intact M. hominis, containing 600 mug of phosphatidylglycerol as to 6 mug of phosphatidylglycerol in the optimal configurational arrangement of a mixed phosphatidylglycerol/phosphatidylcholine/cholesterol micelle. It is concluded that the major part of the phosphatidylglycerol in native M. hominis membranes is masked, probably by membrane proteins, and is not accessible to the anti-phosphatidylglycerol antibodies.     

Characterization of a novel Pseudomonas sp. that mineralizes high concentrations of pentachlorophenol.

A pentachlorophenol (PCP)-mineralizing bacterium was isolated from polluted soil and identified as Pseudomonas sp. strain RA2. In batch cultures, Pseudomonas sp. strain RA2 used PCP as its sole source of carbon and energy and was capable of completely degrading this compound as indicated by radiotracer studies, stoichiometric release of chloride, and biomass formation. Pseudomonas sp. strain RA2 was able to mineralize a higher concentration of PCP (160 mg liter-1) than any previously reported PCP-degrading pseudomonad. At a PCP concentration of 200 mg liter-1, cell growth was completely inhibited and PCP was not degraded, although an active population of Pseudomonas sp. RA2 was still present in these cultures after 2 weeks. The inhibitory effect of PCP was partially attributable to its effect on the growth rate of Pseudomonas sp. strain RA2. The highest specific growth rate (mu = 0.09 h-1) was reached at a PCP concentration of 40 mg liter-1 but decreased at higher or lower PCP concentrations, with the lowest mu (0.05 h-1) occurring at 150 mg liter-1. Despite this reduction in growth rate, total biomass production was proportional to PCP concentration at all PCP concentrations degraded by Pseudomonas sp. RA2. In contrast, final cell density was reduced to below expected values at PCP concentrations greater than 100 mg liter-1. These results indicate that, in addition to its effect as an uncoupler of oxidative phosphorylation, PCP may also inhibit cell division in Pseudomonas sp. strain RA2.(ABSTRACT TRUNCATED AT 250 WORDS)     

T-strain mycoplasma in the chimpanzee.

Specimens from 4 chimpanzees were cultured for T-strain mycoplasma and Mycoplasma hominis. T-strain mycoplasmas were recovered from the genital tract and throat of a male and the genital tract of his female cagemate; neither had clinical evidence of infection. Two other male chimpanzees were culturally negative for T-strain mycoplasmas. M hominis was not isolated from any of the animals. The chimpanzee may serve as a suitable experimental model for studying the role of T-strain mycoplasmas in human urethritis and reproductive failure.     

Potential for thermophilic (50 degrees C) anaerobic dechlorination of pentachlorophenol in different ecosystems.

Thermophilic (50 degrees C) anaerobic biodegradation of pentachlorophenol (PCP) was investigated by using different inocula from natural ecosystems and anaerobic digesters. The inocula tested were three freshwater sediments, four anaerobic sewage sludge samples from digesters treating sludge from wastewater plants with various industrial inputs, and digested manure from an anaerobic reactor. Only one digested-sludge sample and the manure sample were from thermophilic environments. The initial PCP concentration was 7.5 or 37.5 microM. After 8 months, PCP had disappeared from the sediment samples and various, less chlorinated intermediates were present. Additions of extra PCP were degraded within 4 weeks, and a maximal observed dechlorination rate of 1.61 mumol/liter/day in the vials with addition of 7.5 microM PCP and 7.50 mumol/liter/day in the vials with addition of 37.5 microM PCP were measured for a freshwater sediment. In contrast, only 2.8 to 17.5% of the initial PCP added had disappeared from the sludge samples after 8 months of incubation. The complex pattern of intermediates formed indicated that the dechlorination of PCP proceeded via different pathways, involving at least two different populations in the dechlorination processes.