Glyceraldehyde-3-phosphate dehydrogenase of Paracoccidioides brasiliensis is a cell surface protein involved in fungal adhesion to extracellular matrix proteins and interaction with cells

The pathogenic fungus Paracoccidioides brasiliensis causes paracoccidioidomycosis, a pulmonary mycosis acquired by inhalation of fungal airborne propagules, which may disseminate to several organs and tissues, leading to a severe form of the disease. Adhesion to and invasion of host cells are essential steps involved in the infection and dissemination of pathogens. Furthermore, pathogens use their surface molecules to bind to host extracellular matrix components to establish infection. Here, we report the characterization of the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) of P. brasiliensis as an adhesin, which can be related to fungus adhesion and invasion. The P. brasiliensis GAPDH was overexpressed in Escherichia coli, and polyclonal antibody against this protein was obtained. By immunoelectron microscopy and Western blot analysis, GAPDH was detected in the cytoplasm and the cell wall of the yeast phase of P. brasiliensis. The recombinant GAPDH was found to bind to fibronectin, laminin, and type I collagen in ligand far-Western blot assays. of special note, the treatment of P. brasiliensis yeast cells with anti-GAPDH polyclonal antibody and the incubation of pneumocytes with the recombinant protein promoted inhibition of adherence and internalization of P. brasiliensis to those in vitro-cultured cells. These observations indicate that the cell wall-associated form of the GAPDH in P. brasiliensis could be involved in mediating binding of fungal cells to fibronectin, type I collagen, and laminin, thus contributing to the adhesion of the microorganism to host tissues and to the dissemination of infection.

Mastite subclínica bubalina por Aspergillus fumigatus

This research aimed to report the occurrence of subclinical mastitis in a buffalo from a study carried out with 548 milk samples of 137 Murrah and Mediterranean buffalos from seven milk properties, located in the cities of Jau, Botucatu and Sorocaba, State of São Paulo. The animals of the study were submitted to a clinical examination of the mammary gland by the inspection and to the diagnosis of clinical and subclinical mastitis by California Mastitis Test (CMT), being the milk samples later directed to the laboratory for microbiological studies and also to the test of Whiteside Modified (WSM). The isolated agents were identified by the morphological characteristics of its colonies and through microcultive staining with blue cotton. Two (02) pure fungi samples were isolated representing 2.86% of the total isolated microorganism, corresponding to two mammary rooms in one animal, and were classified as pertaining to the Aspergillus fumigatus specie. The animal in question showed reaction of ++ to the CMT in both affected rooms and negative reaction to the WSM. In this way it is concluded that the Aspergillus fumigatus participates in a discrete way as a determinant agent of bubaline subclinical mastitis, however it is important because the affected animals can act as potential reservoirs and may be able to generate the infection in human beings.

Bioleaching of metals from anaerobic sewage sludge: Effects of total solids, leaching microorganisms, and energy source

The effects of municipal sewage sludge solids concentration, leaching microorganisms (Thiobacillus thiooxidans or Thiobacillus ferrooxidans) and the addition of energy source (SO or Fe(II)) on the bioleaching of metals from sewage sludge has been investigated under laboratory conditions using shake flasks. The results show that metal solubilization was better accomplished if additional energy source is supplemented to the microorganisms and that T. thiooxidans furnishes, in general, more adequate conditions for the bioleaching than T. ferrooxidans. At a total solids concentration of 70 g L-1 (originally present in the sludge) pH drop and ORP increase are attenuated, so metal solubilization is negatively affected. Tt was also demonstrated that if lead (Pb) solubilization is to be achieved, than a special combination of microorganism/energy source must be applied.

Antibiosis associated to Lactobacillus acidophilus growth .2. Optimization of some culture parameters in whey and soy milk medium

Whey supplemented with soy milk has been used as a low-cost alternative in the growth of Lactobacillus acidophilus for the production of antimicrobial compounds. Response Surface Metodology has been employed in order to study the effects of initial pH, incubation temperature and soy milk rate for supplementation in the production of antimicrobial substance. It has been observed that both tested microrganisms used (S. aureus and E. coli) were inhibited by antimicrobial substance produced by L. acidophilus. The results obtained with E. coli inhibition did not follow the employed statistical model. on the other hand, when the tested microorganism S. aureus was used, the best inhibition results have been obtained when L. acidophilus was incubated at 36.80 degrees C in whey with 5.6 initial pH and 31,90% (v/v) rate supplemented with soy milk. The analysed antimicrobial substances were nor acids neither hidrogen peroxid.

Studies on the respiration rate of free and immobilized cells of Cephalosporium acremonium in cephalosporin C production

Bioprocesses using filamentous fungi immobilized in inert supports present many advantages when compared to conventional free cell processes. However, assessment of the real advantages of the unconventional process demands a rigorous study of the limitations to diffusional mass transfer of the reagents, especially concerning oxygen. In this work, a comparative study was carried out on the cephalosporin C production process in defined medium containing glucose and sucrose as main carbon and energy sources, by free and immobilized cells of Cephalosporium acremonium ATCC 48272 in calcium alginate gel beads containing alumina. The effective diffusivity of oxygen through the gel beads and the effectiveness factors related to the respiration rate of the microorganism were determined experimentally. By applying Monod kinetics, the respiration kinetics parameters were experimentally determined in independent experiments in a complete production medium. The effectiveness factor experimental values presented good agreement with the theoretical values of the approximated zero-order effectiveness factor, considering the dead core model. Furthermore, experimental results obtained with immobilized cells in a 1.7-L tower bioreactor were compared with those obtained in 5-L conventional fermenter with free cells. It could be concluded that it is possible to attain rather high production rates working with relatively large diameter gel beads (ca. 2.5 mm) and sucrose consumption-based productivity was remarkably higher with immobilized cells, i.e., 0.33 gCPC/kg sucrose/h against 0.24 gCPC/kg sucrose/h in the aerated stirred tank bioreactor process. (C) 1999 John Wiley & Sons, Inc.

Cultivation of Rubrivivax gelatinosus in fish industry effluent for depollution and biomass production

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The influence of fermentation time and the presence of salts in the rheology of the fermentation broth of a polysaccharide-producing bacteria free of soil

Rheological studies were carried out in the fermentation broth of a polysaccharide-producing microorganism free of soil. This microorganism was designated 4B. The bacteria 4B was inoculated in the fermentation broth, which consisted of a carbon source and mineral salts, and it was incubated in a rotating agitator at 30 degreesC for 72 h at 210 rpm. A rheometer of concentric cylinders equipped with a thermostatic bath was used and the readings were taken at 25 degreesC. A study was made of the influence of the fermentation time and the readings were made after 24, 48 and 72 h of incubation, using, separately, sucrose and glucose as carbon sources. The influence of the salt concentrations was determined in each carbon source; the salts used were NaCl, KCl and CaCl2 in the concentrations of 0.4%, 1.0%, 2.0% and 3.0%. It was observed that the fermentation broth behaves as a non-Newtonian fluid and it presents pseudoplastic behaviour. Calculations were made of the flow behaviour index (n) and the consistency index (k) of the samples after 24, 48 and 72 h of fermentation, and it was observed that the 72 h sample presented higher k and consequently higher apparent viscosity. of the carbon sources used, the sucrose presented higher viscous broths after 24 and 48 h, and the glucose after 72 h of fermentation. With relation to the effect of the addition of salts, the CaCl2 presented a higher influence on the viscosity of the fermentation broths. (C) 2001 Elsevier B.V. Ltd. All rights reserved.

Xylanase production by Bacillus circulans D1 using maltose as carbon source

Bacillus circulans D1 is a good producer of extracellular thermostable xylanase. Xylanase production in different carbon sources was evaluated and the enzyme synthesis was induced by various carbon sources. It was found that D-maltose is the best inducer of the enzyme synthesis ( 7.05 U/ mg dry biomass at 48 h), while D-glucose and D-arabinose lead to the production of basal levels of xylanase. The crude enzyme solution is free of cellulases, even when the microorganism was cultivated in a medium with D-cellobiose. When oat spelt xylan was supplemented with D-glucose, the repressive effect of this sugar on xylanase production was observed at 24 h, only when used at 5.0 g/ L, leading to a reduction of 60% on the enzyme production. on the other hand, when the xylan medium was supplemented with D- xylose ( 3.0 or 5.0 g/ L), this effect was more evident ( 80 and 90% of reduction on the enzyme production, respectively). Unlike that observed in the xylan medium, glucose repressed xylanase production in the maltose medium, leading to a reduction of 55% on the enzyme production at 24 h of cultivation. Xylose, at 1.0 g/ L, induced xylanase production on the maltose medium. on this medium, the repressive effect of xylose, at 3.0 or 5.0 g/ L, was less expressive when compared to its effect on the xylan medium.

Miniaturized structures for removal or selection of particles from liquid flow

The aim of this work was the development of miniaturized structures useful for retention and/or selection of particles and viscous substances from a liquid flow. The proposed low costs structures are similar to macroscopic wastewater treatment systems, named baffles, and allow disassemble. They were simulated using FEMLAB 3.2b package and manufactured in acrylic with conventional tools. Tests for retention or selection of particles in water or air and viscous fluids in water were carried out. Either in air or water particles with 50 mu m diameter will be retained but not with 13 mu m diameter. In aqueous flow, it is also possible the retention of viscous samples, such as silicone 350 cSt. The simulated results showed good agreement with experimental measurements. These miniaturized structures can be useful in sample pretreatment for chemical analysis and microorganism manipulation. (C) 2007 Elsevier B.V. All rights reserved.

Feeding preference of the South American endemic anomuran Aegla platensis (Decapoda, Anomura, Aeglidae)

In order to determine the feeding preference of Aegla platensis in streams and the importance of microorganisms in its detritivore diet, we carried out two experiments designed to evaluate the food preferences of A. platensis (1) among leaves with different levels of microbial colonization and (2) among insect larvae (Chironomidae, Simuliidae, Hydropsychidae) and microbially conditioned leaves. A. platensis preferred animal over plant food items; when only leaves were offered, this aeglid preferred the leaves with higher levels of microorganism conditioning.

Zymomonas mobilis: um microrganismo promissor para a fermentação alcoólica

In many countries, fermentation studies regarding the use of bacteria instead of yeasts to reduce the period of alcoholic fermentation have been carried out. In Brazil, all the industrial alcohol production is carried out by yeasts as fermentation microorganisms and little is known about other microorganisms with potential to produce alcohol industrially. Brazil stands out in the energy sector worldwide and thus some institutions have been selecting microorganisms which are more efficient in the alcohol production process. Alcoholic bacteria from species Zymomonas mobilis present technological characteristics with potential to be used for alcoholic fermentation at industrial scale, since it exhibits promising abilities to transform sugars into alcohol and carbon dioxide, at conditions similar to the ones required by yeasts. Zymomonas mobilis is a unique bacteria among the microbial world, with peculiar growth, energy production and response to culture conditions, causing a great interest in scientific, biotechnological and industrial fields. The bacteria's ability to make possible energy production in favor of product formation, respond to physical and chemical environmental manipulation as well as its limited product formation make it an ideal microorganism for the study and development of microbial processes for ethanol production.

Experimental infection of bovines with oocysts of Toxoplasma gondii

Calves aged 3 mth were readily infected with oocysts and cysts of Toxoplasma gondii administered by the oral route. Fever, respiratory distress, nasal discharge, and hyperemia of the conjunctivas were the most significant clinical signs noted in the infected animals. Parasitemia was demonstrated in all infected calves. It occurred on different days and up to 62 days after the infection. Toxoplasma was demonstrated in tissues of all infected calves, and the organ most frequently parasitized was the lymph node. Parasitism of the retina was demonstrated in 2 calves. All infected animals had antibody against T. gondii in their serum. The Sabin-Feldman dye test and the indirect immunofluorescent test were both useful in detecting antitoxoplasma antibody.