Mycelial growth and microscopic characteristics of Thermomyces lanuginosus Tsiklinskaya in YpSs medium with different carbon sources

Muitos fungos termofílicos são conhecidos como sendo produtores de lipases e o potencial dessas enzimas nas reações de esterificação (reação inversa à hidrólise), há muito tem sido reconhecida. O aspecto do micélio e diversas observações microscópicas foram efetuadas em Thermomyces lanuginosus cultivado em Placas de Petri com meios de culturas YpSs (extrato de levedura + amido + agar) e mais quatro variações na fonte de carbono neste meio. As matérias-primas usadas e avaliadas foram pentaeritritol, ácido oléico e dioleato de pentaeritritol como possíveis fontes de carbono disponíveis ao microrganismo são comumente encontradas na indústria química como intermediários clássicos na síntese de diversos ésteres. Com o crescimento de Thermomyces lanuginosus em todos os meios propostos e a manutenção da capacidade de reprodução mostramos ser esse fungo altamente promissor em futuros trabalhos de biocatálise com microrganismos vivos.

Electron scattering and effects of sources of light on photoconductivity of SnO2 coatings prepared by sol-gel

Electro-optical properties of sol-gel derived 2 mol% antimony or niobium doped tin dioxide films have been measured. The electron density has been calculated considering all the relevant scattering mechanisms and experimental conductivity data measured in the range -197 to 25 degrees C. The results support the hypothesis that both ionised impurity scattering and grain boundary scattering have comparable effects in the resistivity of coatings, for free electron density congruent to 5 x 10(18) cm(-3). We have measured variation of photoconductivity excitation with wavelength using xenon and deuterium lamp as light sources. Results show that the main band in the photoconductivity spectrum is dependent on the spectral light source emission, the excitation peak reaching 5 eV (deuterium lamp). This band is due to the recombination process involving oxygen species and photogenerated electron-hole pairs. (C) 1999 Elsevier B.V. B.V. All rights reserved.

Sources of atmospheric acidity in an agricultural-industrial region of São Paulo State, Brazil

[1] Surface-based measurements of atmospheric formic acid (HCOOH), acetic acid (CH3COOH), sulfur dioxide (SO2), hydrogen chloride (HCl), and nitric acid (HNO3) were made in central São Paulo State, Brazil, between April 1999 and March 2000. Mean concentrations were 9.0 ppb (HCOOH), 1.3 ppb (CH3COOH), 4.9 ppb (SO2), 0.3 ppb (HCl), and 0.5 ppb (HNO3). Concentrations in sugar cane burning plumes were 1160-4230 ppb (HCOOH), 360-1750 ppb (CH3COOH), 10-630 ppb (SO2), 4-210 ppb (HCl), and 14-90 ppb (HNO3). Higher ambient concentrations of SO2, HCl and HNO3 were measured during the burning season (May-November). Concentrations of SO2 and HCl increased during the evening, and of HCOOH and CH3COOH were lowest in the morning, with peak levels in the afternoon. Ratios obtained between different species showed either nighttime maxima (SO2/HCOOH, SO2/CH3COOH, SO2/HNO3, CH3COOH/HNO3, SO2/HCl and HCOOH/HNO3), daytime maxima (HCOOH/HCl, CH3COOH/HCl and HNO3/HCl), or no clear trends (HCOOH/CH3COOH). Correlation analysis showed that SO2 and HCl were primary emissions from biomass burning and road transport; HCOOH, HNO3 and CH3COOH were products of photochemistry; HCOOH and CH3COOH were emitted directly during combustion as well as from biogenic sources. Biomass burning affected atmospheric acidity on a regional scale, while vehicular emissions had greater impact in urban and adjacent areas. Atmospheric ammonia levels were insufficient to neutralize atmospheric acidity, which was mainly removed by deposition to the surface.

Ability of bacteriophages isolated from different sources to reduce Salmonella enterica serovar enteritidis in vitro and in vivo

Salmonella enterica serovar Enteritidis-lysing bacteriophages isolated from poultry or human sewage sources were used to reduce Salmonella Enteritidis in vitro and in experimentally infected chicks. Cocktails of 4 different bacteriophages obtained from commercial broiler houses (CB4O) and 45 bacteriophages from a municipal wastewater treatment plant (WT45O) were evaluated. In experiment 1, an in vitro crop assay was conducted with selected bacteriophage concentrations (105 to 101 pfu/mL) to determine ability to reduce Salmonella Enteritidis in the simulated crop environment. Following 2 h at 37 degrees C, CB40 or WT45O reduced Salmonella Enteritidis recovery by 1.5 or 5 log, respectively, as compared with control. However, CB40 did not affect total SE recovery after 6 h, whereas WT45O resulted in up to a 6-log reduction of Salmonella Enteritidis. In experiment 2, day-of-hatch chicks were challenged orally with 3 x 103 cfu /chick Salmonella Enteritidis and treated cloacally with 1 X 109 WT45O pfu/chick I h postchallenge. One hour later, chicks were treated or not with a commercially available probiotic (Floramax-B11). Both treatments significantly reduced Salmonella Enteritidis recovery from cecal tonsils at 24 h following vent lip application as compared with controls, but no additive effect was observed with the combination of bacteriophages and probiotic. In experiment 3, day-of-hatch chicks were challenged orally with 9 x 103 cfu/chick Salmonella Enteritidis and treated via oral gavage with I X 108 CB40 pfu/chick, 1.2 x 108 WT45O pfu/chick, or a combination of both, I h postchallenge. All treatments significantly reduced Salmonella Enteritidis recovered from cecal tonsils at 24 h as compared with untreated controls, but no significant differences were observed at 48 h following treatment. These data suggest that some bacteriophages can be efficacious in reducing SE colonization in poultry during a short period, but with the bacteriophages and methods presently tested, persistent reductions were not observed.

PATHOGENIC OR POTENTIALLY PATHOGENIC BACTERIA AS CONTAMINANTS OF FRESH-WATER FROM DIFFERENT SOURCES IN ARARAQUARA, BRAZIL

The microbiological quality of various fresh waters in the Araraquara region, state of São Paulo, Brazil was investigated. Ninety-nine water samples were taken from rivers, reservoirs, artesian and non-artesian wells, springs and tap waters, and these waters were analysed using: plate counts of heterotrophic microorganisms (per 1 ml); Most Probable Number (MPN) of fecal coliforms and E. coli (per 100 ml); tests for presence of Salmonella, Shigella, Yersinia, the E. coli pathogens of classes EPEC, ETEC and EIEC and Mycobacterium, Shigella, Yersinia and enteroinvasive E. coli (EIEC) were not isolated. The other types of microorganisms were isolated in varying proportions. We conclude that the waters investigated represent a potential microbiological health risk.

UNRUH-DEWITT DETECTORS IN THE PRESENCE OF SCALAR SOURCES

We analyze the response of Unruh-DeWitt detectors in the presence of inertial scalar sources. We show that, in general, a detector responds to the corresponding Coulomb field. However, in some cases, pure vacuum contributions can overwhelm the influence of the Coulomb field rendering the effect of the external source on the detector's response arbitrarily small. We revisit in this context the celebrated question of whether uniformly accelerated observers can see the radiation coming from an inertial charge, and point out the present impediments to answering this question.

Influence of Sources and Meteorology on Surface Concentrations of Gases and Aerosols in a Coastal Industrial Complex

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Orthodontic brackets removal under shear and tensile bond strength resistance tests - a comparative test between light sources

We have investigated if a new LEDs system has enough efficient energy to promote efficient shear and tensile bonding strength resistance under standardized tests. LEDs 470 +/- 10 nm can be used to photocure composite during bracket fixation. Advantages considering resistance to tensile and shear bonding strength when these systems were used are necessary to justify their clinical use. Forty eight human extracted premolars teeth and two light sources were selected, one halogen lamp and a LEDs system. Brackets for premolar were bonded through composite resin. Samples were submitted to standardized tests. A comparison between used sources under shear bonding strength test, obtained similar results; however, tensile bonding test showed distinct results: a statistical difference at a level of 1% between exposure times (40 and 60 seconds) and even to an interaction between light source and exposure time. The best result was obtained with halogen lamp use by 60 seconds, even during re-bonding; however LEDs system can be used for bonding and re-bonding brackets if power density could be increased.

The primary sources of carbon loss during the crop-establishment period in a subtropical Oxisol under contrasting tillage systems

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)