Microbiota bacteriana no processamento industrial de frangos e sua influencia na vida util de carcacas refrigeradas / Bacterial flora in the industrial processing of chickens and their influence in shelf-life of refrigerated carcasses

Visando investigar qualitativa e quantitativamente a participacao da microbiota psicrotrofila e patogenica em carcacas de frango durante e apos o processamento industrial, foram examinadas cento e oitenta unidades de amostras coletadas ao longo do processo em uma industria do Estado de Santa Catarina (Brasil). Numa segunda etapa, foi estudado o comportamento de cinco sanificantes de uso comercial, objetivando verificar a eficiencia dos mesmos na extensao da vida util de carcacas de frango refrigeradas. As contagens medias de microrganismos aerobios em carcacas de frango no inicio do processamento apresentaram valores oscilando entre '10 POT.4'e '10 POT.6' ufc/'cm POT.2' com incubacao a 7 graus centigrados e '10 POT.5' e > '10 POT.6' ufc/'cm POT.2' quando incubadas a 20 graus centigrados e trinta e cinco graus centigrados, respectivamente. Estes valores nao foram muito diferentes daqueles obtidos nas analises do produto final

Sobrepoblación bacteriana del intestino delgado y diarrea crónica / Chronic diarrhea and small bowell bacterial overgrowth

Se estudiaron de modo prospectivo 40 pacientes adultos atendidos en el Consultorio Externo del Servicio de Gastroenterología del Hospital Cayetano Heredia (Lima), catalogados como casos de Diarrea Crónica (DC), por presentar diarrea en un período mayor de 3 semanas. Los pacientes fueron sometidos a exámenes de laboratorio: hematológicos, bioquímicos, coproparasitológicos y coprocultivos. Exámenes endoscópico digestivo y radiografías de tórax y transito intestinal. En 36 casos se practicó el cultivo del contenido duodenal mediante la técnica del Enterotest, con el objeto de determinar la existencia de Sobrepoblación Bacteriana del Intestino Delgado Alto (SOBIA); por el hallazgo de cuentas totales mayor de 10000 gérmenes por ml, y/o coliformes mayor de 1000 gérmenes por ml. Los resultados de los 36 casos mostraron 13 casos (36.1 por ciento) con diagnóstico finales únicos y en 23 casos (63.8 por ciento) éstos eran mixtos, indicando la multifactoriedad de causas de DC. Los diagnósticos principales, fueron Trastornos psicoemocionales 15 casos (41.6 por ciento), SOBIA 11 casos (30.5 por ciento), Parasitosis 6 casos (16.6 por ciento), 2 casos de Diabetes Mellitus (5.5 por ciento), un caso (2.7 por ciento) con Tuberculosis Intestinal y un caso (2.7 por ciento) Desnutrición. El hallazgo el 30.5 por ciento de Sobrepoblación Bacteriana del Intestino Delgado Alto, correspondería a una cifra mayor de la población adulta sana de Lima, y ocupa el segunda lugar en frecuencia de causas de Diarrea Crónica en el presente estudio, confirmando esta importante asociación ya antes señalada por otros investigadores. Orienta a ampliar estos estudios, más aún al tratarse de pacientes que pertenecían a sectores socio-económicos bajos y con limitadas condiciones de saneamiento ambiental

[Analysis of cellular fatty acids of Enterobacteria species by gas chromatography-mass spectrometry].

Cellular fatty acid compositions of 15 Enterobacteria were analyzed by gas chromatography-mass spectrometry(GC-MS). About 30 fatty acids were detected in chromatograms, and 13 of them were chemically identified, e.i. C11:0, C12:0, C13:0, C14:0, C15:0, 2OH-C14:0, 3OH-C14:0, C16:1, C16:0, aC17:0, delta C17:0, C18:1 and C18:0. The major cellular fatty acids in all fifteen species were C16:0, C18:1, C15:0, C14:0, C16:1, C13:0, 3OH-C14:0 and C18:0. The cellular fatty acids of Enterobacteria species were characterized by normal straight-chain saturated acids and monounsaturated acids, of which the most abundant fatty acid was C16:0. 3OH-C14:0 was found in all strains of Enterobacteria, whereas 2OH-C14:0 was only found in strains of Serratia species. Other unknown compositions also would have been certain characteristics for bacteria. The present paper would provide some of useful reference data for chemotaxonomy and molecular microbiology of Enterobacteria.

Protein kinase and phosphoprotein phosphatase activities of nitrogen regulatory proteins NTRB and NTRC of enteric bacteria: roles of the conserved amino-terminal domain of NTRC.

The NTRC protein (ntrC product) of enteric bacteria activates transcription of nitrogen-regulated genes by a holoenzyme form of RNA polymerase that contains the ntrA product (sigma 54) as sigma factor. Although unmodified NTRC will bind to DNA, it must be phosphorylated to activate transcription. Both phosphorylation and dephosphorylation of NTRC occur in the presence of the NTRB protein (ntrB product). We here demonstrate rigorously that it is the NTRB protein that is a protein kinase by showing that NTRB can phosphorylate itself, whereas NTRC cannot. Phosphorylated NTRC (NTRC-P) is capable of autodephosphorylation with a first-order rate constant of 0.14-0.19 min-1 (t 1/2 of 5.0-3.6 min) at 37 degrees C. In addition, there is regulated dephosphorylation of NTRC-P. By contrast to the autophosphatase activity, regulated dephosphorylation requires three components in addition to NTRC-P: the PII regulatory protein, NTRB, and ATP. NTRC is phosphorylated within its amino-terminal domain, which is conserved in one partner of a number of two-component regulatory systems in a wide variety of eubacteria. A purified amino-terminal fragment of NTRC (approximately equal to 12.5 kDa) is sufficient for recognition by NTRB and is autodephosphorylated at the same rate as the native protein.

Media for study of growth kinetics and envelope properties of iron-deprived bacteria.

Ion-exchange chromatography was used to remove iron from complex and chemically defined laboratory media. The kinetics of metal cation removal from the media was investigated by using atomic absorption spectrophotometry, and the results indicated that over 90% of the iron could be eliminated from certain complex media by this treatment. The treated medium was used for growth studies in a gram-positive and a number of gram-negative organisms that were isolated from infections in humans. High-molecular-weight outer membrane proteins that are known to be induced under iron-depleted growth conditions (iron-regulated membrane proteins) were observed when a number of gram-negative pathogens were cultivated in the treated media. Iron uptake by Staphylococcus aureus varied, depending on the iron content of the medium.

Calidad microbiológica de los quesos producidos a nivel artesanal en Costa Rica / Microbiological quality of home-made cheese produced in Costa Rica

Se analizaron 205 muestras de quesos hechos a partir de leche cruda entera, los cuales se producen en forma artesanal en seis zonas rurales de Costa Rica. La finalidad fue determinar la calidad microbiológica de los mismos y formular recomendaciones tendientes a reducir al mínimo las condiciones sanitarias deficientes de elaboración del producto. La muestras se recolectaron directamente en las fincas productoras, y se sometieron a los análisis microbiológicos seguientes: Staphylococcus aureus, termonucleasa (TNasa) positivo); Determinación del número más probable (MPN) de coliformes fecales; Recuento total de hongos y levaduras; y Recuento de mesófilas aerobias. Según se contató, todas las muestras contenían altos recuentos de los cuatro microorganismos investigados, demostrando, por conseguiente, la calidad microbiológica deficiente de los quesos producidos artesanalmente. Con base en los resultados obtenidos, se emite una serie de recomendaciones prácticas orientadas a mejorar las condiciones sanitarias inadecuadas bajo las cuales se elabora actualmente el producto

Comparison of the exoproducts of gram-negative bacteria by SDS-Page.

The protein exoproducts released during exponential growth of Gram-negative bacteria were analysed and compared by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-Page). The following bacterial strains were tested: Escherichia coli, Klebsiella pneumoniae, Citrobacter freundii, Enterobacter cloacae, Serratia liquefaciens, Serratia rubidaea, Proteus mirabilis, Proteus vulgaris, Salmonella minnesota, Pseudomonas aeruginosa and Pseudomonas fluorescens. It is demonstrated by SDS-Page that members of one species show identical protein pattern, whereas different species show besides comparable protein bands a species characteristic pattern. All members of Enterobacteriaceae were shown to release proteins whose molecular weights fell into the following size regions: Each strain was shown to synthesize a polypeptide of molecular weight 34,000 and one or more polypeptides within the molecular weight range 25,000-29,000. This profile was shown to be clearly different from that of Pseudomonas strains where 20 or more distinct polypeptides ranging from 12,500 to 160,000 Mr were detectable.

The transfer RNA of certain Enterobacteriacae contain 2-methylthiozeatin riboside (ms2io6A) an isopentenyl adenosine derivative.

Isopentenyl adenosine derivatives are always located adjacent to the 3' end of the anticodon in transfer RNA and have been implicated in certain biological functions. In the enteric bacterium, E. coli, the derivative is ms2i6A whereas in some plant associated bacteria the derivative is the hydroxylated form, ms2io6A. Anti-i6A immunoadsorbent chromatography has been employed to detect isopentenyl adenosine compounds. In the present study we show that the transfer RNA of three species of enteric bacteria, S. typhimurium, K. pneumoniae, and S. marcescens contains both ms2io6A and ms2i6A. Under the growth conditions utilized the ms2io6A is predominant. The presence of ms2io6A in Enterobacteriacae is particularly noteworthy since in previous work it has been found only in plant-associated species of bacteria.

[Firefly assay of bacterial ATP: comparative study of extraction methods (author's transl)]. / Mesure de l'ATP bactérien par bioluminescence: étude critique des méthodes d'extraction.

The firefly bioluminescence ATP assay presents multiple applications in microbiological analysis. Nine ATP extraction methods were tested on thirteen Gram positive and Gram negative bacterial species. The DMSO method appears as the procedure for choice. It provides the highest yields and the best reproducibility, even at high bacterial concentrations. It is simple, rapid and can be recommended for routine analysis. Assays carried out after extraction by this procedure show that in 24 hours cultures, the ATP content ranges from 0.28 fg to 15.65 fg per cell depending on species.

Purification and characterization of cloacin DF13 receptor from Enterobacter cloacae and its interaction with cloacin DF13 in vitro.

Extraction of the crude cell envelope fraction of cloacin DF13-susceptible Enterobacter cloacae strain 02 with Triton X-100 and ethylenediaminetetraacetate solubilized an outer membrane fraction which neutralized the lethal activity of cloacin DF13. A similar fraction could not be isolated from strains known to be lacking functional cloacin DF13 receptors. On this basis the isolated outer membrane fraction was assumed to contain the specific cloacin DF13 receptor. The receptor was purified to homogeneity by acetone precipitation and affinity chromatography, using cloacin DF13 as a ligand. The purified receptor was identified as a protein which consisted of a single polypeptide chain with an apparent molecular weight of 90,000 and a preponderance of acidic amino acids (pI = 5.0). The interaction of equimolar amounts of purified receptor and cloacin DF13 in vitro resulted in a complete, irreversible neutralization of the lethal activity of the bacteriocin. This interaction showed a temperature optimum at 43 degrees C but was only slightly affected by variation of the pH between 5.0 and 8.5 or by increasing the ionic strength of the incubation buffer. The receptor had no neutralizing activity towards other bacteriocins, such as colicin E1 or colicin E3.

Occurrence of glutathione in bacteria.

Glutathione and soluble thiol content were examined in a broad spectrum of bacteria. Significant soluble thiol was present in all cases. The thiol compound was glutathione in most of the gram-negative bacteria but not in most of the gram-positive bacteria studied. Glutathione was absent in four anerobes and one microaerophile but was present in a blue-green bacterium. The glutathione content of Escherichia coli increased significantly during transition from exponential to stationary phase.

Analysis of bacterial biotin-proteins.

The biotin-protein populations in several bacterial strains were analyzed by solubilization of [3H]biotin-labeled cells with sodium dodecylsulfate followed by electrophoresis on polyacrylamide gels containing the detergent. A variety of patterns of biotin-labeled polypeptide chains was seen, ranging from a single biotin-protein in Escherichia coli, corresponding to the biotin carboxyl carrier protein component of acetyl-CoA carboxylase, to multiple species in Enterobacter aerogenes, Pseudomonas citronellolis, Bacillus cereus, Propionibacterium shermanii, Lactobacillus plantarum, and Mycobacterium phlei, which probably represent subunits of multiple biotin-dependent enzymes present in these organisms. In the case of Pseudomonas citronellolis two major biotin-containing polypeptides with approximate molecular weights of 65 000 and 25 000 were shown to correspond to the biotin carboxyl carrier components of pyruvate carboxylase and acetyl-CoA carboxylase, respectively. Thus in the case of Pseudomonas citronellolis two different biotin-dependent enzymes in the same cell do not share common biotin carboxyl carrier subunits.

The nature, intergeneric distribution and biosynthesis of isoprenoid quinones and phenols in gram-negative bacteria.

1. Twenty-two aerobically grown Gram-negative bacteria were analysed for demethylmenaquinones, menaquinones, 2-polyprenylphenols, 6-methoxy-2-polyprenylphenols and ubiquinones. 2. All the eight enterobacteria and both the two facultative organisms (Aeromonas punctata and Aeromonas hydrophila) examined contain all the compounds listed above. The principal homologues are octaprenyl; in addition lower (down to tri- or tetra-prenyl for the 2-polyprenylphenols) and sometimes higher homologues are also present. 3. Strict aerobes are of two types, those that contain 2-polyprenylphenols, 6-methoxy-2-polyprenylphenols and ubiquinones, and those that contain ubiquinones only. The principal homologues are generally octa- or nona-prenyl, although one organism (Agrobacterium tumefaciens) has ubiquinone-10 as its principal homologue. As in the enterobacteria, lower homologues of these compounds are also present. 4. In Escherichia coli W, Pseudomonas ovalis Chester and Pseudomonas fluorescens, radioactivity from p-hydroxy[U-(14)C]benzoic acid is incorporated into 2-polyprenylphenols, 6-methoxy-2-polyprenylphenols, 6-methoxy-3-methyl-2-polyprenyl-1,4-benzoquinones, ubiquinones and a compound tentatively identified as 2-polyprenyl-1,4-benzoquinone. The fact that radioactivity is incorporated into the first three compounds suggests that in these organisms, and indeed in all those Gram-negative bacteria that contain 2-polyprenylphenols and 6-methoxy-2-polyprenylphenols, ubiquinones are formed by a biosynthetic sequence similar to that in Rhodospirillum rubrum. 5. The finding in ;Vibrio O1' (Moraxella sp.) and organism PC4 that 2-polyprenylphenols and 6-methoxy-2-polyprenylphenols are chemically and radiochemically undetectable leads to the conclusion that they are not intermediates in the biosynthesis of ubiquinone by these and by other Gram-negative bacteria that do not contain detectable amounts of 2-polyprenylphenols and 6-methoxy-2-polyprenylphenols. However, ;Vibrio O1' (organism PC4 was not examined) does contain 6-methoxy-3-methyl-2-polyprenyl-1,4-benzoquinone. 6. In Ps. ovalis Chester, radioactivity from l-[Me-(14)C]methionine is incorporated into the nuclear C-methyl and O-methyl groups of 6-methoxy-3-methyl-2-polyprenyl-1,4-benzoquinones and ubiquinone-9, and into the O-methyl group of 6-methoxy-2-polyprenylphenols.