RESUMO
Outer membrane proteins (OMPs) expressed by Vibrio tubiashii under different environmental growth conditions were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, N-terminal amino acid sequencing, and PCR analyses. Results showed the presence of a 38- to 40-kDa OmpU-like protein and ompU gene, a maltoporin-like protein, several novel OMPs, and a regulatory toxR homolog.
Assuntos
Proteínas da Membrana Bacteriana Externa , Proteínas de Bactérias , Proteínas de Ligação a DNA , Fatores de Transcrição , Vibrio/crescimento & desenvolvimento , Adesinas Bacterianas/química , Adesinas Bacterianas/genética , Adesinas Bacterianas/metabolismo , Sequência de Aminoácidos , Proteínas da Membrana Bacteriana Externa/química , Proteínas da Membrana Bacteriana Externa/genética , Proteínas da Membrana Bacteriana Externa/isolamento & purificação , Proteínas da Membrana Bacteriana Externa/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Eletroforese em Gel de Poliacrilamida , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Porinas/química , Porinas/genética , Porinas/metabolismo , Receptores Virais/química , Receptores Virais/genética , Receptores Virais/metabolismo , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Fatores de Transcrição/química , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Vibrio/classificação , Vibrio/genética , Vibrio/metabolismoRESUMO
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) was used for the characterization of a partially transesterified poly(beta-hydroxyalkanoate) (PHA), a polymer produced by the bacterial strain Alcaligenes eutrophus with saponified vegetable oils as the sole carbon sources. The transesterification was carried out separately under acidic and basic conditions to obtain PHA oligomers weighing <10 kDa. The intact oligomers were detected in their cationized forms, [M + Na]+ and [M + K]+, by MALDI-TOFMS. A composition analysis, using the MALDI-TOF spectra, indicated that the oligomers obtained via acid catalysis contained a methyl 3-hydroxybutyrate end group, and those obtained by base catalysis had a methyl crotonate (olefinic) end group. In addition to hydroxybutyrate (HB), the oligomers were found to contain a small percentage of hydroxyvalerate, which was independently confirmed by gas chromatography/mass spectrometry. In comparison, analysis of a commercial PHA polymer, transesterified under identical conditions, showed only the presence of HB, i.e., a pure poly(HB) homopolymer.
Assuntos
Poliésteres/análise , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
The synthetic gene probe is a 20 mer oligonucleotide, derived from listeriolysin O gene sequence of Listeria monocytogenes and shown to be specific for strains of this organism. This probe was used in a DNA-colony hybridization assay to evaluate its suitability in detecting (ß-hemolytic L. monocytogenes in ground beef. Thirty-six ground beef samples were plated onto three media: Trypticase soy agar with 0.6% yeast extract, lithium chloride-phenylethanol-moxalactam agar and Martin's agar, both directly and after selective enrichment in Food and Drug Administration broth. Of the 118 gram-positive and catalase-positive isolates selected from the plates, only 24 gave detectable hybridization signal with the probe. CAMP-test and standard biochemical tests also revealed that only these 24 probe positive isolates were (ß-hemolytic L. monocytogenes . Of the 36 samples of ground beef, 6 were positive for Listeria spp., out of which 4 were L. monocytogenes .
RESUMO
A total of 1,409 gram-negative bacterial colonies were randomly selected from 19 samples of fresh and spoiled ground beef plated on six media. Only 137 (9.7%) were oxidase negative, and 20 (14.6%) of these were Acinetobacter spp., all of which were recovered from fresh meat samples. The importance of this group in both fresh and spoiled beef is less than is generally believed.
Assuntos
Acinetobacter/isolamento & purificação , Contaminação de Alimentos , Microbiologia de Alimentos , Bactérias Gram-Negativas/isolamento & purificação , Carne , Animais , Bovinos , Meios de Cultura , Bactérias Gram-Negativas/enzimologia , Oxirredutases/biossíntese , Especificidade da EspécieRESUMO
Solid media were employed to determine the presence and absence of extracellular enzyme production by two genera of fruit-rot fungi, Rhizopus and Mucor. The results of this investigation revealed that phosphatase was released into the cultural medium by all the fungi examined; however, only R. oryzae, R. tritici, M. mucedo, and M. piriformis showed the possibility of being high producers of the enzyme. Protease, urease, ribonuclease, pectate lyase, and polygalacturonase, at varying levels of activity, were detected, in the majority of the fungi, in the cultural medium.
Assuntos
Mucor/enzimologia , Rhizopus/enzimologia , Meios de Cultura , Peptídeo Hidrolases/biossíntese , Ribonucleases/biossínteseRESUMO
A fluorescent metabolite present in seven members of the genus Rhizopus was isolated. This compound appeared green before spray treatment and purple after spray treatment with p-anisaldehyde in visible light. Subsequent purification and structural elucidation of the isolated compound yielded 1-[2,6,10,14-tetramethyl-17-carbomethyl heptadecyl]-1-[2,6,10,14-tetramethyl-17-methanoyl heptadecyl]-benzene.
