SciELO Brasil - Scientific Electronic Library Online
(53.052 recursos)
SciELO (Scientific Electronic Library Online) is an electronic library covering a selected collection of Brazilian scientific journals. The objective of the site is to implement an electronic virtual library, providing full access to a collection of serial titles, a collection of issues from individual serial titles, as well as to the full text of articles. The project envisages the development of a common methodology for the preparation, storage, dissemination and evaluation of scientific literature in electronic format.
Mostrando recursos 1 - 20 de 97
1.
MICROBIAL COUNTS OF DARK RED LATOSOL SAMPLES STORED AT DIFFERENT TEMPERATURES - Vieira,Francisco Cleber Sousa; Nahas,Ely
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...
2.
MICROBIAL ACTIVITY OF DARK RED LATOSOL SAMPLES STORED AT DIFFERENT TEMPERATURES - Vieira,Francisco Cleber Sousa; Nahas,Ely
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.
3.
ANTIBIOTIC PRODUCTION BY STREPTOMYCES HYGROSCOPICUS D1.5: CULTURAL EFFECT - Bhattacharyya,Barun K.; Pal,Sushil C.; Sen,Sukanta K.
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.
4.
A Preliminary Note on Yeasts Associated With Fecal Pellets of Rodents and Marsupials of Atlantic Forest Fragments in Rio de Janeiro, Brazil - Abranches,Jacqueline; Nóbrega,Hilda N.; Valente,Patrícia; Mendonça-Hagler,Leda C.; Hagler,Allen N.
Yeasts had mean counts of above 106 CFU/g in the fecal pellets of small mammals from tropical forest fragments. Most of the 55 species isolated were fermentative ascomycetes, with the most frequent being Debaryomyces hansenii, Pichia membranifaciens and Issatchenkia orientalis, whereas Rhodotorula mucilaginosa was the most frequent yeast of basidiomycetous affinity.
5.
Cell envelope components of Yersinia pestis grown in intraperitoneal diffusion chambers - Ferreira,Rita C. C.; Neto,Armando A. B.; Fracalanzza,Sérgio E. L.; Costa,Sérgio O. P.; Almeida,D. F.; Ferreira,Luís C. S.
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...
6.
Frequency of Nonfermentative Gram-Negative Bacilli Isolated from Clinical Materials of Pacients at Universidade Federal do Ceará Hospital Complex - Brazil - Frota,Cristiane Cunha; Moreira,José Luciano Bezerra
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...
7.
Transfer of clindamicyn resistance between Bacteroides fragilis group strains isolated from clinical specimens - Carvalho,Cibele B. Mano de; Moreira,José Luciano B.; Ferreira,Maria Candida S.
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.
8.
Ribonuclease Production by Aspergillus species - Gomes,Eleni; Silva,Roberto da; Serzedello,Alcides
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...
9.
EVALUATION OF THE VIABILITY OF PLEUROTUS SPP. STRAINS AFTER LIQUID NITROGEN CRYOPRESERVATION - Lara-Herrera,Isabel; Mata,Gerardo; Gaitán-Hernández,Rigoberto
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...
10.
MORPHOLOGICAL, CYTOLOGICAL, AND CULTURAL ASPECTS OF CURVULARIA PALLESCENS - Freire,Sônia Valéria Pereira; Paiva,Laura Mesquita; Lima,Elza Aúrea de Luna-Alves; Maia,Leonor Costa
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.
11.
Growth of Pediococcus acidilactici on sugar cane blackstrap molasses - Sant?Anna,Ernani S.; Torres,Regina Coeli O.
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...
12.
FRUITY AROMA PRODUCTION BY Ceratocystis fimbriata IN SOLID CULTURES FROM AGRO-INDUSTRIAL WASTES - Bramorski,Adriana; Soccol,Carlos R.; Christen,Pierre; Revah,Sergio
Solid state fermentations were carried out to test the efficacy of Ceratocystis fimbriata to grow on different agro-industrial substrates and aroma production. Seven media were prepared using cassava bagasse, apple pomace, amaranth and soya bean. All the media supported fungal growth. While amaranth medium produced pineapple aroma, media containing cassava bagasse, apple pomace and soya bean produced a strong fruity aroma. The aroma production was growth dependent and the maximum aroma intensity was detected a few hours before or after the maximum respirometric activity. Sixteen compounds were separated by gas cromatography of the components present in the headspace and fifteen...
13.
INHIBITION OF MAYARO VIRUS REPLICATION BY PROSTAGLANDIN A1 IN Aedes albopictus CELLS - Barbosa,Joel Antonio; Rebello,Moacyr Alcoforado
Prostaglandin A1 (PGA1) inhibits Mayaro virus replication in Aedes albopictus cells at nontoxic doses to uninfected cells. At 10 µg/ml, PGA1 decreases virus production by 90%. The presence of PGA1 during virus adsorption, with no treatment after infection, reduces virus yield by 41%. Antiviral activity is observed even when treatment starts at one or two hours post-infection. However, in cells pre-treated with PGA1 during 24 hours, virus replication is not impaired. Thus, events ocurring during initial stages of infection and after virus adsorption and penetration must be the target of PGA1 action. SDS-PAGE analysis of 35S-methionine labelled proteins shows that...
14.
INTERFERON SELECTIVELY INHIBITS THE SYNTHESIS OF MAYARO VIRUS GLYCOPROTEINS - Ferreira,Davis F.; Rebello,Maria Christina Soares
We have previously observed that interferon (recIFNa2b) blocks the process of morphogenesis of Mayaro virus in TC7 cells (monkey kidney). In this work we show that IFNa inhibits preferentially virus glycoproteins and their precursors, and this effect is probably correlated to the alterations in the morphogenesis process previously observed.
15.
Aeromonas species isolated from PINTADO fish (Pseudoplatystoma sp): virulence factors and drug susceptibility - Rall,Vera Lúcia Mores; Iaria,Sebastião Timo; Heidtmann,Sandra; Pimenta,Fabiana Cristina; Gamba,Rosa Carvalho; Pedroso,Débora Midori Myaki
Aeromonas has been described as an emergent foodborne pathogen of increasing importance. In this study, we report that 48% of 50 Pintado fish samples collected at the retail market of São Paulo city were positive for Aeromonas sp, as detected by the direct plating method. When the presence/absence method was used, the positivity was 42%. A. caviae was the most frequent species, followed by A. hydrophila and A. sobria. Production of cytotoxic enterotoxin, observed in suckling mouse assay, was detected in 67% of A. sobria strains, in 60% of A. hydrophila strains and in 40% of A. caviae strains. In...
16.
ANTAGONISM AGAINST VIBRIO CHOLERAE BY BACTERIAL DIFFUSIBLE COMPOUND IN THE FECAL MICROBIOTA OF RODENTS - Silva,Simone Helena da; Vieira,Enio Cardillo; Nicoli,Jacques Robert
In an ex vivo agar plate assay, we monitored the appearance of an inhibitory halo against Vibrio cholerae from the feces of Wistar and Fischer rats aged 10 to 42 days. The frequency of Wistar rats showing halo increased from 0% (10 days) to a maximum of 80.0% (29 days) and then decreased to 53.3% (42 days). A similar pattern was obtained with Fischer rats but with a lower intensity (maximum frequency of 50.0% by day 36). In a separate experiment, when Wistar rats were fed a low-protein diet for 7 days, the inhibitory halo decreased drastically. Three apparently different...
17.
Molecular evolution in bacteria: cell division - Trevors,J.T.
Molecular evolution in bacteria is examined with an emphasis on the self-assembly of cells capable of primitive division and growth during early molecular evolution. Also, the possibility that some type of encapsulation structure preceeded biochemical pathways and the assembly of genetic material is examined. These aspects will be considered from an evolutionary perspective.
18.
Sugar-cane juice induces pectin lyase and polygalacturonase in Penicillium griseoroseum - Minussi,Rosana Cristina; Soares-Ramos,Juliana Rocha Lopes; Coelho,Jorge Luiz Cavalcante; Silva,Daison Olzany
The use of other inducers as substitutes for pectin was studied aiming to reduce the production costs of pectic enzymes. The effects of sugar-cane juice on the production of pectin lyase (PL) and polygalacturonase (PG) by Penicillium griseoroseum were investigated. The fungus was cultured in a mineral medium (pH 6.3) in a rotary shaker (150 rpm) for 48 h at 25oC. Culture media were supplemented with yeast extract and sucrose or sugar-cane juice. Sugar-cane juice added singly to the medium promoted higher PL activity and mycelial dry weight when compared to pectin and the use of sugar-cane juice and yeast...
19.
Chromium uptake from aqueous effluents by immobilized Baker's yeast - Menezes,Lucia Beckmann C.; Braz,Vera Nobre; Cordeiro,Carlos Alberto M.
Baker?s yeast immobilized in alginate was used to take up chromium from effluents. Chromium in aqueous solutions were used in different concentrations. To evaluate the viability and efficiency the baker?s yeast for chromium uptake from effluents three experiments done in two differents reactor systems: first in system 1 at 17.5 ml/s and with 10, 20, 25 and 30 mg/l Cr; second in system 2 at 38.7 ml/s with 20 mg/l Cr; third in system 2.1 at 6.65 ml/s and with 20, 30 and 40 mg/l Cr. The efficiency of chromium uptake varied between 86 and 100 %.
20.
Effect of aeration on biodegradation of petroleum waste - Ururahy,Adriana F. P.; Marins,Marcus D. M.; Vital,Ronalt L.; Gabardo,Irene Therezinha; Pereira Jr.,Nei
Large amounts of oily sludge are generated as residues by the oil industry, representing a real problem for refineries. This work studied the technical viability of treating oily sludge biologically, through stimulation of native microorganisms, at bench scale. Such microorganisms were able to grow in a medium containing oily sludge as the only carbon and energy sources. Two oily sludge concentrations were studied, 5% (v/v) and 10% (v/v), with a C:N ratio of 100:1. Higher microbial populations were observed in the first case. Substrate inhibition and/or toxic effect took place in the second case. The importance of aeration on the...
1.
