MICROBIAL ACTIVITY OF DARK RED LATOSOL SAMPLES STORED AT DIFFERENT TEMPERATURES

The enzymatic activity of soil samples stored at temperatures of 5 to -12oC and at room temperature for 0-32 weeks was determined. While alkaline phosphatase and dehydrogenase activity was decreased compared to control in samples stored at low temperatures, acid phosphatase activity showed no significant change

Frequency of Nonfermentative Gram-Negative Bacilli Isolated from Clinical Materials of Pacients at Universidade Federal do Ceará Hospital Complex - Brazil

Among one thousand eight hundred and thirty-four Gram-negative bacilli, isolated at Universidade Federal do Ceará hospital complex - Brazil, from January 1995 to February 1996, 456 (24.8%) were Nonfermentative Gram-Negative Bacilli (NFGNB). This study reports their identification to the species level and their frequency as well. Thirteen genera and thirty species were identified and Pseudomonas aeruginosa was the most frequent species (69.95%), followed by Acinetobacter baumannii (5.48%) and by Acinetobacter lwoffii (3.95%). Among the identified P.aeruginosa strains, 94.1% produced pigment but 7.9% of them produced pigment only after being cultivated several times. The frequency of the most species was similar to that reported in the literature

MORPHOLOGICAL, CYTOLOGICAL, AND CULTURAL ASPECTS OF CURVULARIA PALLESCENS

Curvularia pallescens Boedijn (Hyphomycetes) is redescribed with the aid of a scanning electron microscope, and the optimal cultural conditions for growing this fungus are discussed. Cytological analysis and nuclear condition, observed through the HCl-Giemsa technique, showed vegetative and reproductive structures (hypha and conidia) formed by uni, bi, tri, and multinucleated segments. Cultures of C. pallescens in Complete medium and in Potato dextrose agar varied on growth, on aspects of the border of the colonies and also on medium pigmentation. The Complete medium and the temperature between 25-28°C were the most indicated for growth of C. pallescens

Transfer of clindamicyn resistance between Bacteroides fragilis group strains isolated from clinical specimens

Clindamycin resistance was trasferred by a conjugation-like process from Bacteroides thetaiotaomicron 52, a multiple antibiotic-resistant strain isolated from clinical specimens, to other Bacteroides species. A possible association between a plasmid detected in the donor strain and clindamycin resistance is discussed

ANTIBIOTIC PRODUCTION BY STREPTOMYCES HYGROSCOPICUS D1.5: CULTURAL EFFECT

In an attempt to screen out new potent antibiotic producers from soil, Streptomyces hygroscopicus D1.5 was isolated and was found antagonistic to both bacteria and fungi. It could utilise arginine as nitrogen source and glycerol as carbon source at 0.75 g/l and 11.5 g/l level, respectively for maximum antibiotic yield

Cell envelope components of Yersinia pestis grown in intraperitoneal diffusion chambers

The electrophoretic profiles of penicillin binding proteins (PBPs) and outer membrane proteins (OMPs) of Yersinia pestis EV 76 were determined following in vivo growth in diffusion chambers implanted in the peritoneal cavity of mice. In contrast to Y. pestis grown under in vitro conditions which activate the low calcium response (LCR) regulon there was no significant qualitative or quantitative change of the PBP profile of Y. pestis cells during growth in diffusion chambers for up to 72 h following implantation in mice. Three OMPs, with molecular weight of 100, 60 and 58 kDa, were expressed in Y. pestis cells grown for 24 h, but not at 48 h or at 72 h, in diffusion chambers. These results indicate that growth of Y. pestis in intraperitoneal diffusion chambers activates genes which might be relevant to the growth in the mammal host

Ribonuclease Production by Aspergillus species

Ribonuclease production by Aspergillus flavipes, A. sulphureus and A. fischeri in semi-synthetic medium, after 24-144 hours at 30ºC under shaking, was studied. After cultivation, the medium was separated from micelia by filtration and the resultant solution was used as enzymatic extract. The highest amount of biomass and RNase was obtained after 96 hours of cultivation. The enzymes produced by three species presented similar characteristics, with optimum temperature at 55ºC and two peaks of activity at pH 4.5 and 7.0. A. flavipes RNases were more sensitive to temperature: 50% of the initial activity was lost after 1 hour at 70ºC. After this heat treatment, RNase of A. sulphureus lost 30% of this activity and that of A. fischeri only 16%. The nucleotides released by enzimatic hydrolysis of RNA were separated by ion exchange chromatography in a AG-1X8-formiate column and identified by paper chromatography. This procedure indicated that the raw enzymatic extract of Aspergillus flavipes is able to hydrolyze RNA, releasing 3'-nucleotides monophosphate at pH 4.5 and 3' and 5'-nucleotides monophosphate at pH 7.0 and 8.5. This result suggests that this strain produces two different types of RNase, one acidic and other alcaline, with different specificities

Growth of Pediococcus acidilactici on sugar cane blackstrap molasses

Pediococcus acidilactici (IL01) has grown in MRS (Man, Rogosa and Sharpe) broth modified by substitution of glucose by 2.0% (MRS-2), 3.0% (MRS-3), 4.0% (MRS-4) and 5.0% (MRS-5) sugar cane blackstrap molasses. The highest acid production was obtained in MRS-5 broth maintained at a constant pH of 5.0. The highest biomass production was obtained when P. acidilactici was grown in MRS-5 broth at initial pH 6.5, while productivity was higher in MRS-2 broth (28.16%). When the MRS-2 broth was utilized at initial pH 6.5 for a 20-hour fermentation period, the highest growth rate (dx/dt) was found in a period of 8 to 16 hours (0.290 g cells/L.h), while the specific growth rate (µ) was 0.175 (h-1) for that period, differently from the 0.441 (h-1) obtained for the period comprising the 4th to the 12th hour. The growth in MRS broth was 5.08% (2.95 g/l) higher than in MRS-2 broth (2.80 g/l). The data obtained have shown that P. acidilactici has had a significant growth in molasses as the main carbon source, and that it is possible to substitute MRS glucose by this carbon source with the purpose of obtaining a more economical growth medium for the potential large scale productions

MICROBIAL COUNTS OF DARK RED LATOSOL SAMPLES STORED AT DIFFERENT TEMPERATURES

The number of colony forming units (CFU) of different groups of bacteria and fungi in samples stored at temperatures of 5 to -12oC for 0-32 weeks was evaluated. The number of CFU obtained after the different periods of storage of red latossol soil was compared with the number of colonies obtained immediately after removal of soil samples (time zero). The number of total bacteria and actinomycetes in the samples remained practically unchanged throughout the storage period. The number of Gram-negative bacteria decreased by as much as 69% compared to control, while the number of Bacillus spp and of fungi increased 1.9 to 4.9 times starting from the 12th week in samples stored at 5oC. Except for the variations observed in fungal counts, the remaining groups of bacteria practically showed the same variation in number of colonies in soil samples stored at 5oC and -12oC

EVALUATION OF THE VIABILITY OF PLEUROTUS SPP. STRAINS AFTER LIQUID NITROGEN CRYOPRESERVATION

Viability of 6 mushroom strains of the Pleurotus genus (2 from P. djamor var. djamor, 1 from P. ostreatus var. ostreatus, 2 from P. ostreatus var. columbinus and 1 from P. pulmonarius) after liquid nitrogen cryopreservation (-196º) was evaluated. The contact time for the mycelia of these strains with the cryoprotectant (glycerol) was studied 1, 2 and 3 hours before freezing. We also tested the effect of different times (5, 10 and 15 minutes) and temperatures (30, 45 and 60ºC) of the thawing system for mycelial recovery. The results showed a marked tendency toward faster mycelial recovery when samples were thawed at 30ºC, while at 60ºC no recovery was observed. A change in thawing and contact times with the cryoprotectant did not affect the results significantly, as the thawing temperature and strain employed affected