Asunto(s)
Botulismo/epidemiología , Brotes de Enfermedades/estadística & datos numéricos , Animales , Aspartato Aminotransferasas/sangre , Austria/epidemiología , Biomarcadores , Toxinas Botulínicas/sangre , Botulismo/diagnóstico , Botulismo/transmisión , Clostridium botulinum/aislamiento & purificación , Criopreservación , Heces/microbiología , Manipulación de Alimentos , Microbiología de Alimentos , Conservación de Alimentos , Fragaria/efectos adversos , Fragaria/microbiología , Humanos , Carne/efectos adversos , Carne/microbiología , Productos de la Carne/efectos adversos , Productos de la Carne/microbiología , Ratones , Ratones Endogámicos BALB C , Sus scrofaRESUMEN
AIMS: To investigate properties of the proteolytic activity of a yeast cell wall lytic soil bacterium identified as an Arthrobacter species. METHODS AND RESULTS: The organism was grown at pH 7.5 and 30 degrees C in shake flasks on media with different complex subtrates. Highest proteolytic activity assayed with azocaseine was detected in media with wheat gluten. In addition, l-leucine, l-alanine exopeptidase activity and esterase activity were found. The proteolytic activity showed stability up to pH 12, with a maximum at pH 11. The temperature optimum was at 55 degrees C, but there was a loss in enzyme activity of 50% within 2 h. The proteolytic activity was inhibited by 3,4-dichloroisocumarin, whereas there was little or no effect with EDTA, pepstatin A or E64. CONCLUSIONS: The proteolytic activity is highly alkaline stable. The formation of the enzyme can be induced by media with high protein content.
Asunto(s)
Arthrobacter/metabolismo , Arthrobacter/crecimiento & desarrollo , Caseínas/metabolismo , Pared Celular/metabolismo , Medios de Cultivo , Endopeptidasas/metabolismo , Concentración de Iones de Hidrógeno , Metaloendopeptidasas/metabolismo , Saccharomyces cerevisiae/metabolismo , Microbiología del Suelo , Especificidad por Sustrato , TemperaturaRESUMEN
A new Lactobacillus species from pig small intestine has been identified. In an attempt to isolate Lactobacillus reuteri strains carrying the putative colonization-factor gene (mub, for mucus binding) a mub-derived gene probe was used to screen pig intestinal material. A number of isolates were obtained and primary characterization showed that they were Gram-positive, catalase-negative, non-spore-forming, non-motile rods. Growth occurred at 45 degrees C but not at 15 degrees C and the DNA G+C content was 46 mol%. Cell wall analysis together with DNA-DNA hybridization and analysis of the 16S rRNA sequence revealed that the new isolates represent a previously undescribed Lactobacillus species closely related to L. reuteri, Lactobacillus fermentum and Lactobacillus pontis. The name Lactobacillus mucosae is proposed for this species and the type strain is S32T.
Asunto(s)
Intestino Delgado/microbiología , Lactobacillus/clasificación , Moco/metabolismo , Porcinos/microbiología , Animales , Proteínas Bacterianas/metabolismo , Técnicas de Tipificación Bacteriana , Composición de Base , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Mucosa Intestinal/microbiología , Lactobacillus/crecimiento & desarrollo , Lactobacillus/aislamiento & purificación , Lactobacillus/metabolismo , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Filogenia , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADNRESUMEN
A semicontinuous microbial assay for the determination of halogenated short-chain hydrocarbons in water samples was developed. The bacterium Xanthobacter autotrophicus GJ 10 forms dehalogenating enzymes, which liberate the halides in 1,2-dichloroethane as halogen ions. Cells of the organism were immobilized in chitosan beads and placed into a tube reactor, whose outlet was connected to a flow-through cell with chloride-selective potentiometric electrodes. Water samples were delivered continuously to the system, and the EMF was recorded. Both the difference in EMF between blank and sample and the velocity of the EMF change were used for calibration. The detection limit for 1,2-dichloroethane was below 0.5 mg/L; the relative standard deviation was <10%. The effects of several parameters like flow rate and cell density were studied in detail.