Vancomycin resistant enterococci

Enterococci are normal intestinal flora in humans. Among enterococci, Enterococcus faecalis and Enterococcus faecium are frequently isolated and can become nosocomial pathogens in hospitals, especially in intensive care units and oncology wards. Recently, vancomycin-resistant enterococci (VRE) such as E. faecalis and E. faecium have caused a serious problem of hospital-acquired infections in Europe and the USA. VRE also has another aspect as a cause of community-acquired infections. Especially, avoparcin which had been used to enhance growth of food animals is documented as associated with the spread of VRE in European countries. In Japan, there have only been a few of reports about VRE so far. However, there evidence that VRE might become prevalent in many hospitals in Japan. In fact, we have already isolated another highly vancomycin-resistant E. faecium (VCM:MIC > 128 micrograms/ml) from a hospitalized diabetic patient. We should pay a careful attention to VRE and perform the following control measures: 1)re-education and re-training about hospital infection control procedures, 2) prudent use of vancomycin in clinical settings, 3)accurate report of VRE in clinical laboratories, and 4) good communications and collaborations among physicians, nurses and other health care personnel and laboratory technicians. We should learn more from countries in which VRE are already prevalent, and pursue further investigations, to prevent the spread of VRE in Japan.     

Photoproduction of hydrogen from raw starch using a halophilic bacterial community

The bacterial community designated BC1, which originates from night soil treatment sludge, exhibited a strong ability to produce H2 from raw starch in the light in the presence of 3% NaC1. Three halophilic or halotolerant bacterial species, Vibrio fluvialis, Rhodobium marinum, and Proteus vulgaris, were isolated from BC1 and identified. The level of H2 production from starch by coculture of V. fluvialis and R. marinum was nearly equal to that by BC1, indicating that these two strains play roles in starch degradation and H2 production from the degraded products in BC1, respectively. Acetic acid and ethanol, which were detected as the major products of degradation of starch by V. fluvialis in pure culture, seemed to be mainly utilized for H2 production by R. marinum in BC1 and the coculture. However, R. marinum in pure culture could not produce H2 from a synthetic medium containing acetic acid and ethanol, suggesting that V. fluvialis supplied not only substrates but also some unknown factors capable of inducing H2 production from these substrates by R. marinum. A study using the starch-rich microalgae, Chlamydomonas reinhardtii and Dunaliella tertiolecta, demonstrated that the above coculture could be applied to the production of H2 at high yield from raw starch in an algal biomass.     

Superoxide dismutases exhibit oxidase activity on aldehyde alcohols similar to alcohol oxidase from Paenibacillus sp. AIU 311

The relations between oxidase activity on aldehyde alcohols and superoxide dismutase (SOD) were investigated, since the amino terminal amino acid sequence of alcohol oxidase (AOD) from Paenibacillus sp. AIU 311, which was specific to aldehyde alcohols, exhibited high similarity to those of SODs containing manganese (Mn(2+)-SOD). Paenibacillus AOD had high SOD activity. The SODs containing manganese, iron, or copper and zinc also exhibited oxidase activities on aldehyde alcohols, and the relative values of oxidase activities on aldehyde alcohols to SOD activity of Mn(2+)-SOD were closer to those of Paenibacillus AOD compared with those of the other SODs. Thus, SODs had AOD activity on aldehyde alcohols as another enzyme activity, and the Paenibacillus AOD and Mn(2+)-SOD were classified into a similar group.     

Accelerated biodegradation of pyrene and benzo[a]pyrene in the Phragmites australis rhizosphere by bacteria-root exudate interactions

We investigated the biodegradation of pyrene and benzo[a]pyrene in Phragmites australis rhizosphere sediment. We collected P. australis plants, rhizosphere sediments, and unvegetated sediments from natural aquatic sites and conducted degradation experiments using sediments spiked with pyrene or benzo[a]pyrene. Accelerated removal of pyrene and benzo[a]pyrene was observed in P. australis rhizosphere sediments with plants, whereas both compounds persisted in unvegetated sediments without plants and in autoclaved rhizosphere sediments with sterilized plants, suggesting that the accelerated removal resulted largely from biodegradation by rhizosphere bacteria. Initial densities of pyrene-utilizing bacteria were substantially higher in the rhizosphere than in unvegetated sediments, but benzo[a]pyrene-utilizing bacteria were not detected in rhizosphere sediments. Mycobacterium gilvum strains isolated from rhizosphere sediments utilized pyrene aerobically as a sole carbon source and were able to degrade benzo[a]pyrene when induced with pyrene. Phragmites australis root exudates containing phenolic compounds supported growth as a carbon source for the one Mycobacterium strain tested, and induced benzo[a]pyrene-degrading activity of the strain. The stimulatory effect on benzo[a]pyrene biodegradation and the amounts of phenolic compounds in root exudates increased when P. australis was exposed to pyrene. Our results show that Mycobacterium-root exudate interactions can accelerate biodegradation of pyrene and benzo[a]pyrene in P. australis rhizosphere sediments.     

Decolorization of heat-treatment liquor of waste sludge by a bioreactor using polyurethane foam-immobilized white rot fungus equipped with an ultramembrane filtration unit

A bench-scale bioreactor using immobilized fungal cells equipped with an ultramembrane filtration unit was developed as a means of decolorizing brown color components (melanoidins) arising from the heat-treatment liquor (HTL) of waste sludge. Artificial HTL containing 4200 color units of synthetic melanoidin supplemented with 1000 mg/l ethanol was first subjected to decolorization by the fungus Coriolus hirsutus IFO4917 immobilized onto polyurethane foam cubes. Then, the resultant biologically treated HTL was subjected to ultrafiltration to obtain the permeate (filtrate) as the effluent. The retentate (concentrate) of the filtration unit, containing the remaining melanoidin of high molecular weight and extracellular decolorizing enzymes, was returned to the fungal bioreactor to allow further decolorization. This system was operated in a sequencing batch mode under nonsterile conditions. Contamination of the bioreactor with air/water-born microbes markedly lowered the decolorization efficiency. However, this problem was solved by heating the returned concentrate at 50 degrees C for 10 min. Under the almost stable condition of a hydraulic retention time of 2 d in a 1-d cycle sequencing batch mode, about 70% decolorization was routinely achieved using the entire system (bioreactor + ultrafiltration), while the contribution of the fungal bioreactor alone to the decolorization was about 45%.     

Effect of inorganic redox cocatalyst on Pd‐catalyzed oxidative carbonylation of phenol for direct synthesis of diphenyl carbonate

A catalyst system for direct synthesis of diphenyl carbonate by oxidative carbonylation of phenol was investigated with special emphasis on the inorganic redox cocatalyst component. Besides the inorganic redox cocatalyst, the catalyst system was composed of a Pd carbonylation catalyst, an organic redox cocatalyst, a base and a drying agent. Ce(OAc)₃·H₂O was found to be the most efficient inorganic redox cocatalyst giving DPC in 76% yield with a Pd turnover number of 250 and without producing any major side products. This revised version was published online in July 2006 with corrections to the Cover Date.     

Is the anti-stress effect of vitamin C related to adrenal gland function in rat?

The aim of this study was to investigate whether vitamin C influences the stress response system of the adrenal gland. Adrenalectomized (ADX) rats and non-ADX rats were administered vitamin C and were subjected to electroshock stress (ES) for 5 days. After loading the final stress, stress-related behaviors and corticosterone (CORT), vitamin C, and adrenocorticotropin-releasing hormone (ACTH) levels in the blood were measured. Vitamin C supplementation decreased CORT levels in non-ADX rats. Stress decreased the mean value of rearing frequency in both non-ADX and ADX rats, while vitamin C partially enhanced it only in non-ADX. Vitamin C supplementation decreased mean ACTH level in both groups. It also significantly decreased freezing time increased by stress. Lastly, vitamin C motivated both groups to cross over an electric field more frequently as compared to their respective control groups. These results suggest that the alleviating effect of vitamin C on stress-related rearing behavior was exerted via modulation of CORT, but its effect on freezing behavior may be attributed to corticotropin-releasing hormone (CRH) or ACTH.