Os biossurfatantes (BS) são produtos de origem microbiana com propriedades tensoativas e emulsificantes. Estes compostos são candidatos para substituir os surfatantes sintéticos em aplicações industriais devido à sua menor toxicidade, maior biodegradabilidade, maior diversidade química e maior eficiência e efetividade em condições físicas extremas de salinidade, pressão e temperatura. O uso comercial e industrial dos BS ainda não é sustentável devido a seu alto custo de produção relacionado principalmente ao baixo rendimento. A utilização de substratos de baixo custo e ferramentas estatísticas para melhorar o rendimento de produção dos BS são duas das principais estratégias para tratar este problema. O objetivo do trabalho foi estudar a produção e recuperação do BS produzido por B. luteolum, visando o melhoramento na sua produção através do uso do planejamento fatorial e caracterizar a estrutura química do BS. A partir dos resultados, determinou-se que a adsorção em resina foi mais efetiva para a recuperação do BS comparada com a precipitação ácida. A produção do BS foi melhorada através de um planejamento fatorial 23 usando como fatores as concentrações da fonte de carbono (vaselina), a fonte de nitrogênio (nitrato de amônio) e a água do mar artificial e como resposta a tensão superficial da solução 0...
Brevibacterium spp. are catalase-positive, non-spore-forming, non motile, aerobic Gram- positive rods that were considered apathogenic until a few reports of infections in immunocompromised patients had been published. To the best of our knowledge, this is the ﬁrst report of B. casei catheter-related bloodstream infection in a child with acute leukemia. We aim to enhance the awareness of pediatric hematology and infectious disease specialists about this pathogen and review of the literature.
Various cultivation parameters were optimized for the production of extra cellular protease by Brevibacterium linens DSM 20158 grown in solid state fermentation conditions using statistical approach. The cultivation variables were screened by the Plackett-Burman design and four significant variables (soybean meal, wheat bran, (NH4)2SO4 and inoculum size were further optimized via central composite design (CCD) using a response surface methodological approach. Using the optimal factors (soybean meal 12.0g, wheat bran 8.50g, (NH4)2SO4) 0.45g and inoculum size 3.50%), the rate of protease production was found to be twofold higher in the optimized medium as compared to the unoptimized reference medium.
Brevibacterium sp. was isolated from the blood of an acutely ill 18-year-old female with AIDS. The isolate was identified as Brevibacterium casei by use of carbohydrate assimilation tests. Treatment was successful with intravenously administered ciprofloxacin. To our knowledge, this is the first report of sepsis caused by B. casei in a human immunodeficiency virus-infected patient.
In the present study we aimed to observe the intracellular responses when there was a hyperosmotic shock with a large shift in ionic strength in nutrient-rich and nutrient-poor external environments in order to clarify the availability of substrates. To do this, we used the halotolerant organism Brevibacterium sp. strain JCM 6894, which is able to grow in the presence of a wide range of salt concentrations. Hyperosmotic shock was induced by transferring cells in the late exponential phase of growth in a complex medium containing 0.5 M NaCl into either old or fresh culture medium containing 2 M NaCl. Changes in the growth rate, in the pH of the medium, and in the internal cation or organic solute concentrations in the cytosol after an upshock were analyzed as a function of incubation time. The cells exhibited very different responses to upshocks in fresh culture medium and in old culture medium; in fresh culture medium, growth was stimulated and the medium became more acidic, whereas the old culture medium repressed growth and the medium became more alkaline. The intracellular free Na+ concentrations remained low (80 nmol mg of protein−1) after an upshock in fresh culture medium, although they quickly increased twofold in the old culture medium. In contrast...
Linocin M18 is an antilisterial bacteriocin produced by the red smear cheese bacterium Brevibacterium linens M18. Oligonucleotide probes based on the N-terminal amino acid sequence were used to locate its single copy gene, lin, on the chromosomal DNA. The amino acid composition, N-terminal sequence, and molecular mass derived from the nucleotide sequence of an open reading frame of 798 nucleotides coding for 266 amino acids found on a 3-kb BamHI restriction fragment correspond closely to those obtained from the purified protein (N. Valdés-Stauber and S. Scherer, Appl. Environ. Microbiol. 60:3809-3814, 1994). No sequence homology to any protein or nucleotide sequences deposited in databases was found. Comparison of the nucleotide sequence and the N-terminal amino acid sequence derived from the protein suggests that B. linens M18 produces an N-formyl-methionyl-CAC tRNA. A wide taxonomical distribution of the gene within coryneform bacteria has been demonstrated by PCR amplification. The structural gene from linocin M18 is present at least in three Brevibacterium species, five Arthrobacter species, and five Corynebacterium species.
Thirty-seven bacteriophages plaquing on Corynebacterium, Brevibacterium, or Arthrobacter strains were isolated from soil or vegetation samples. Restriction analysis of phage DNA indicated that 20 phages were unique; one of them produced entirely turbid plaques on Brevibacterium ketoglutamicum and was characterized as temperate. All these phages were assigned to group B of the classification of Bradley (Bacteriol. Rev. 31:230-314, 1967) and had relatively narrow host ranges.
An enantiomer-selective amidase active on several 2-aryl and 2-aryloxy propionamides was identified and purified from Brevibacterium sp. strain R312. Oligonucleotide probes were designed from limited peptide sequence information and were used to clone the corresponding gene, named amdA. Highly significant homologies were found at the amino acid level between the deduced sequence of the enantiomer-selective amidase and the sequences of known amidases such as indoleacetamide hydrolases from Pseudomonas syringae and Agrobacterium tumefaciens and acetamidase from Aspergillus nidulans. Moreover, amdA is found in the same orientation and only 73 bp upstream from the gene coding for nitrile hydratase, strongly suggesting that both genes are part of the same operon. Our results also showed that Rhodococcus sp. strain N-774 and Brevibacterium sp. strain R312 are probably identical, or at least very similar, microorganisms. The characterized amidase is an apparent homodimer of Mr 2 x 54,671 which exhibited under our conditions a specific activity of about 13 to 17 mumol of 2-(4-hydroxyphenoxy)propionic R acid formed per min per mg of enzyme from the racemic amide. Large amounts of an active recombinant enzyme could be produced in Escherichia coli at 30 degrees C under the control of an E. coli promoter and ribosome-binding site.
The biosynthesis of 4-keto and 4,4′-diketo carotenoids in Brevibacterium sp. KY-4313 was studied. Echinenone and canthaxanthin were isolated from the cultures grown on a medium containing several n-alkanes. When glutathione was added to the bacterial cultures, the formation of canthaxanthin was inhibited while β-carotene and its hydroxy derivatives accumulated. It is suggested that these 4-hydroxy compounds, isocryptoxanthin, isozeaxanthin, and 4-hydroxy-4′-keto-β-carotene, are intermediates in the biosynthesis of canthaxanthin. In the presence of 2-(4-chlorophenylthio)-triethylamine hydrochloride or nicotine, lycopene and neurosporene accumulated. The β-carotene level decreased slightly but β-zeacarotene remained unchanged. β-carotene and its derivatives were resynthesized upon removal of the inhibitors. It was concluded that cyclization can take place at either the neurosporene or lycopene level in Brevibacterium sp. KY-4313.
Forty-three strains belonging to the genus Brevibacterium which were encountered in clinical materials over 2 decades were compared with reference strains, including the type strains, of B. casei, B. epidermidis, B. mcbrellneri, B. iodinum, and B. linens. By means of carbohydrate assimilation tests (CATs) the 43 clinical isolates could be assigned to the species B. casei (n = 41) and B. epidermidis (n = 2). DNA-DNA hybridizations were performed for 20 clinical isolates and confirmed the species identification of the isolates. Cellular fatty acid profiles of all strains were determined and found to have less discriminative power than CATs. This is the first report indicating that most clinical Brevibacterium isolates are B. casei and that CATs provide an easy-to-perform method for species determination within the genus, thus avoiding nucleic acid techniques.
Forty-one clinical strains of CDC coryneform groups B-1 and B-3 were compared biochemically, by analysis of cell wall sugars, amino acids, and cellular fatty acids, and by DNA relatedness to the type strains of Brevibacterium casei, Brevibacterium epidermidis, and Brevibacterium linens. Twenty-two strains were shown to be B. casei, while five other strains formed a phenotypically inseparable genomospecies in the same genus. The remaining isolates were genetically heterogeneous, and most are probably members of the genus Brevibacterium. They were not further identified, but they were biochemically distinguishable from B. casei. Eleven of the clinical strains of B. casei were isolated from blood, and two each were isolated from cerebrospinal fluid and from pleural fluid. At least five isolates were from multiple blood or cerebrospinal fluid cultures. To our knowledge, these strains are the first described clinical isolates identified as B. casei, which was previously considered to be a nonpathogenic species.
Cell-free extracts of Brevibacterium sp. L5 grown on DL-erythro-3,5-diaminohexanoate were found to contain a 3-keto-5-aminohexanoate cleavage enzyme that converts 3-keto-5-aminohexanoate and acetyl-coenzyme A (CokA) to 3-aminobutyryl-CoA and acetoacetate and a deaminase that coverts L-3-aminobutyryl-CoA to crotonyl-CoA. The cleavage enzyme has been purified extensively, and some of its properties have been determined for comparison with the 3-keto-6-acetamido-hexanoate cleavage enzyme of Pseudomonas sp. B4. The deaminase has been partially purified and characterized. Both the cleavage enzyme and the deaminase are induced by growth on 3,5-diaminohexanoate. The presence of these and other accessory enzymes in Brevibacterium sp. extracts accounts for the results of earlier tracer experiments which showed that C-1 and C-2 of 3-keto-5-aminohexanoate are converted mainly to acetoacetate and acetate, whereas C-3 to C-6 are converted mainly to 3-hydroxybutyrate or its coenzyme A thiolester. The enzymes observed in extracts of Brevibacterium sp. can account for the conversion of 3,5-diaminohexanoate to acetyl-CoA.
Six coryneforms isolated from blood and dialysate fluid were phenotypically similar to Brevibacterium casei, but 16S rRNA gene sequencing and DNA-DNA hybridization indicate that they belong to a new species for which the name Brevibacterium sanguinis is proposed.
Coryneform bacteria of the genus Brevibacterium occur on the normal skin surface, but reports of human infection with this genus are lacking. A number of cultures of coryneform bacteria sent to the National Collection of Type Cultures for identification have been identified as Brevibacterium spp on the basis of their cell wall composition and ability to produce methane-thiol from L-methionine. We describe a rapid method for the detection of methane-thiol and confirmatory tests which differentiate Brevibacterium from morphologically similar genera.
Coryneform bacteria belonging to the genus Brevibacterium have emerged as opportunistic pathogens. Of the nine known species of Brevibacterium isolated from human clinical samples, Brevibacterium casei is the most frequently reported species from clinical specimens. We report the first case of B. casei brain abscess in an immunocompetent patient successfully treated by surgery and antimicrobial therapy.
Brevibacterium senegalense strain JC43T sp. nov. is the type strain of Brevibacterium senegalense sp. nov., a new species within the Brevibacterium genus. This strain, whose genome is described here, was isolated from the fecal flora of a healthy Senegalese patient. B. senegalense is an aerobic rod-shaped Gram-positive bacterium. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 3,425,960 bp long genome (1 chromosome but no plasmid) contains 3,064 protein-coding and 49 RNA genes.
pAP13 is an 89-kb linear plasmid hosted by Brevibacterium sp. strain Ap13, an actinobacterium isolated from the feces of a flamingo from an extremely high-altitude lake in Argentina. Because of the ecological importance of the genus Brevibacterium, the absolute lack of information concerning Brevibacterium linear plasmids, and the possible ecological significance of this unusual plasmid, pAP13 was completely sequenced, including the inversely oriented termini.
In this study we determined some properties of the cholesterol oxidase from a Brevibacterium strain isolated from buffalo's milk and identified the cholesterol degradation products by the bacterial cell. A small fraction of the enzyme synthesized by cells cultured in liquid medium for 7days was released into the medium whereas a larger fraction remained bound to the cell membrane. The extraction of this fraction was efficiently accomplished in 1 mM phosphate buffer, pH 7.0, containing 0.7% Triton X-100. The enzyme stability under freezing and at 45oC was improved by addition of 20% glycerol. The optimum temperature and pH for the enzyme activity were 53°C and 7.5, respectively. The only steroidal product from cholesterol oxidation by the microbial cell and by the crude extract of the membrane-bound enzyme was 4-colesten-3-one. Chromatographic analysis showed that minor no steroidal compounds as well as 4-colesten-3-one found in the reaction media arose during fermentation process and were extracted together with the enzyme in the buffer solution. Cholesterol oxidation by the membrane-bound enzyme was a first order reaction type.
Two genes, hom (encoding homoserine dehydrogenase) and thrB (encoding homoserine kinase), of the threonine biosynthetic pathway are clustered in the chromosome of Brevibacterium lactofermentum in the order 5' hom-thrB 3', separated by only 10 bp. The Brevibacterium thrB gene is expressed in Escherichia coli, in Brevibacterium lactofermentum, and in Corynebacterium glutamicum and complements auxotrophs of all three organisms deficient in homoserine kinase, whereas the Brevibacterium hom gene did not complement two different E. coli auxotrophs lacking homoserine dehydrogenase. However, complementation was obtained when the homoserine dehydrogenase was expressed as a fusion protein in E. coli. Northern (RNA) analysis showed that the hom-thrB cluster is transcribed, giving two different transcripts of 2.5 and 1.1 kb. The 2.5-kb transcript corresponds to the entire cluster hom-thrB (i.e., they form a bicistronic operon), and the short transcript (1.1 kb) originates from the thrB gene. The promoter in front of hom and the hom-internal promoter in front of thrB were subcloned in promoter-probe vectors of E. coli and corynebacteria. The thrB promoter is efficiently recognized both in E. coli and corynebacteria, whereas the hom promoter is functional in corynebacteria but not in E. coli. The transcription start points of both promoters have been identified by primer extension and S1 mapping analysis. The thrB promoter was located in an 87-bp fragment that overlaps with the end of the hom gene. A functional transcriptional terminator located downstream from the cluster was subcloned in terminator-probe vectors.
pAP13 is an 89 kb-linear plasmid hosted by Brevibacterium sp. Ap13, an actinobacterium isolated from the feces of a flamingo from an extremely high-altitude lake in Argentina. Because of the ecological importance of the genus Brevibacterium, the absolute lack of information concerning Brevibacterium linear plasmids, as well as the as the possible ecological significance of this unusual plasmid, pAP13 was completely sequenced, including the inversely oriented termini.; Fil: Dib, Julian Rafael. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina; Westfälische Wilhelms-Universität Münster; Alemania;; Fil: Schuldes, Jörg. Georg-August-Universität; Alemania;; Fil: Thürner, Andrea. Georg-August-Universität; Alemania;; Fil: Farias, Maria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina;; Fil: Daniel, Rolf. Georg-August-Universität; Alemania;; Fil: Meinhardt, Friedhelm. Westfälische Wilhelms-Universität Münster; Alemania;