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PubMed1965

MICROBIAL DEGRADATION OF ISOPROPYL-N-3 -CHLOROPHENYLCARBAMATE AND 2-CHLOROETHYL-N-3-CHLOROPHENYLCARBAMATE.

Microbial degradation of isopropyl-N-3-chlorophenylcarbamate (CIPC) and 2-chloroethyl-N-3-chlorophenylcarbamate (CEPC) was observed in a soil perfusion system. Degradation in perfused soils, and by pure cultures of effective bacterial isolates, was demonstrated by the production of 3-chloroaniline and the subsequent liberation of free chloride ion. Identified isolates effective in degrading and utilizing CIPC as a sole source of carbon included Pseudomonas striata Chester, a Flavobacterium sp., an Agrobacterium sp., and an Achromobacter sp. Identified isolates, effective in degrading and utilizing CEPC as a sole source of carbon, included an Achromobacter sp. and an Arthrobacter sp. CIPC-effective isolates degraded CEPC more slowly than CIPC, whereas CEPC-effective isolates degraded CIPC more rapidly than CEPC. Both CIPC- and CEPC-effective isolates degraded isopropyl N-phenylcarbamate (IPC) more rapidly than either CIPC or CEPC.

Achromobacter↗

PubMed1963

INHIBITION OF MICROBIAL GROWTH AND SEPARATION BY D-SERINE, VANCOMYCIN, AND MITOMYCIN C.

Durham, Norman N. (Oklahoma State University, Stillwater). Inhibition of microbial growth and separation by d-serine, vancomycin, and mitomycin C. J. Bacteriol. 86:380-386. 1963.-A study was made of the growth and separation inhibition of Pseudomonas fluorescens by vancomycin and mitomycin C and of a Flavobacterium sp. sensitive to mitomycin C and d-serine. Aberrant morphological forms (primarily "boat-shaped" cells and "chain-like" filaments) were observed during growth of the sensitive organism in the presence of the inhibitors. Reversal studies indicated that Mg(++), and to a lesser extent Mn(++), partially reversed vancomycin and mitomycin C growth inhibition during the early stages of growth but did not influence d-serine inhibition. Selected metabolites also showed a tendency to partially reverse mitomycin C and vancomycin inhibition of growth during the initial growth phase, and the differences in reversal trends suggested that d-serine, vancomycin, and mitomycin C produce metabolic lesions at different sites in the cell with respect to growth. Cultivation of the sensitive organism in low concentrations of the inhibitors resulted in a structurally fragile population, indicating formation of a defective cell structure. Mg(++) partially reversed the vancomycin inhibition of separation in these organisms. None of the other metals or metabolites, either singly or in varied combinations, was able to reverse inhibition of separation by the various inhibitors.

Flavobacterium↗

PubMed1990

Beta-lactam antibiotic biosynthetic genes have been conserved in clusters in prokaryotes and eukaryotes.

A cosmid clone containing closely linked beta-lactam antibiotic biosynthetic genes was isolated from a gene library of Flavobacterium sp. SC 12,154. The location within the cluster of the DNA thought to contain the gene for delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine synthetase (ACVS), the first step in the beta-lactam antibiotic biosynthetic pathway, was identified by a novel method. This DNA facilitated the isolation, by cross-hybridization, of the corresponding DNA from Streptomyces clavuligerus ATCC 27064, Penicillium chrysogenum Oli13 and Aspergillus nidulans R153. Evidence was obtained which confirmed that the cross-hybridizing sequences contained the ACVS gene. In each case the ACVS gene was found to be closely linked to other beta-lactam biosynthetic genes and constituted part of a gene cluster.

Anti-Bacterial Agents↗

PubMed1985

Two distinct mechanisms for the interaction of cells with fibronectin substrata.

Fibronectin (Fn) was adsorbed onto neutral, sulfonated, imine-conjugated or gelatin coated polystyrene latex beads. In all cases, the Fn coated beads bound effectively to Chinese hamster ovary (CHO) cells in suspension. However, the binding of Fn coated neutral or positively charged imine conjugated bead was inhibited by low concentrations of heparin or heparan sulfate or by treatment of the cells with Flavobacterium heparanase. By contrast, binding of Fn coated sulfonated or gelatin beads was insensitive to inhibition by heparin and to heparanase treatment of cells. Adhesion of CHO cells to Fn coated tissue culture plastic was not sensitive to heparin, whereas adhesion of CHO cells to Fn-coated imine-conjugated plastic was sensitive to heparin. These observations imply that the functional status of Fn can be modulated by the nature of the surface to which the Fn is adsorbed. They further imply that, under some circumstances, the heparin/heparan sulfate binding domains of Fn can play a role in the attachment of Fn to the cell membrane via membrane proteoglycans. Under other circumstances, the interaction of Fn with the cell may primarily involve other receptors for Fn, presumably cell surface glycoproteins.

Animals↗

PubMed1995

Molecular cloning and sequence analysis of flavastacin: an O-glycosylated prokaryotic zinc metalloendopeptidase.

A new zinc metalloendopeptidase that cleaves peptides on the amino-terminal side of aspartic acid was isolated from the cultural filtrate of Flavobacterium meningosepticum. The gene for this new enzyme was cloned into pBluescript, and the complete nucleotide sequence was determined. Over 40% of the deduced amino acid sequence was verified independently by direct protein microsequencing. The most important structural features of this new enzyme include (i) the presence of an unusual O-linked oligosaccharide of unknown function located at a unique consensus site near the C-terminus and (ii) a characteristic extended zinc-binding site and corresponding Met-turn that places this metalloendopeptidase in the astacin family. This is the first example of a prokaryotic enzyme related to the eukaryotic astacin group; it is being designated hereafter as flavastacin.

Amino Acid Sequence↗

PubMed1994

Isolation of prolylendopeptidase-inhibiting peptides from bovine brain.

The peptides inhibiting prolylendopeptidase were screened and isolated from bovine brain by monitoring the inhibition of prolylendopeptidase produced by Flavobacterium meningosepticum. The amino acid sequence of the peptide having the highest inhibitory activity was determined as Met-Pro-Pro-Pro-Leu-Pro-Ala-Arg-Val-Asp-Phe-Ser-Leu-Ala-Gly-Ala-Leu-Asn. This peptide showed the IC50 and Ki values of 38.4 and 8.6 microM, respectively, for prolylendopeptidase isolated from bovine brain.

Amino Acid Sequence↗

PubMed2002

Using secretion to solve a solubility problem: high-yield expression in Escherichia coli and purification of the bacterial glycoamidase PNGase F.

PNGase F is a widely used deglycosidase, secreted in small amounts by the gram-negative bacterium Flavobacterium meningosepticum. We have designed a T7 promoter-based Escherichia coli expression system to provide a high-yield source of recombinant enzyme. When expressed intracellularly, the enzyme was produced in a largely insoluble state. However, when expressed as a fusion with the leader sequence from the ompA gene, hexahistidine-tagged PNGase F was efficiently processed and exported to the E. coli periplasm. Single-step purification using immobilized metal affinity chromatography yielded 8 mg of pure enzyme per liter of culture, which is fully active on a range of protein and peptide substrates.

Amidohydrolases↗

PubMed1990

Isolation and characterization of a 2-(2,4-dichlorophenoxy) propionic acid-degrading soil bacterium.

The 2-(2,4-dichlorphenoxy)propionic acid (2,4-DP)-degrading bacterial strain MH was isolated after numerous subcultivations of a mixed culture obtained by soil-column enrichment and finally identified as Flavobacterium sp. Growth of this strain was supported by 2,4-DP (maximum specific growth rate 0.2 h-1) as well as by 2,4-dichlorophenoxyacetic acid (2,4-D), 4-(2,4-dichlorophenoxy)butyric acid (2,4-DB), and 2-(4-chloro-2-methylphenoxy)propionic acid (MCPP) as sole sources of carbon and energy under aerobic conditions. 2,4-DP-Grown cells (10(8] of strain MH degraded 2,4-dichlorophenoxyalkanoic acids, 2,4-dichlorophenol (2,4-DCP), and 4-chlorophenol at rates in the range of 30 nmol/h. Preliminary investigations indicate that cleavage of 2,4-DP results in 2,4-DCP, which is further mineralized via ortho-hydroxylation and ortho-cleavage of the resulting 3,5-dichlorocatechol.

2,4-Dichlorophenoxyacetic Acid↗

PubMed1990

Improved production of heterologous protein from Streptomyces lividans.

Protein-secreting procaryotic host organisms are currently being sought as alternatives to Escherichia coli for recombinant processing. In this study we examined how manipulation of the cultivation conditions can enhance heterologous protein production by Streptomyces lividans. The recombinant S. lividans used in this study expressed and excreted a Flavobacterium enzyme capable of hydrolyzing organophosphates. Initial shake-flask studies demonstrated that supplementing Luria-Bertani medium with moderate amounts of glucose (30 g/l), led to improved enzyme production. In fermentor studies with controlled pH, a further twofold increase in production was observed when glucose was fed continuously as compared to batch cultivation. This improved production in the glucose-fed culture may be related to a reduced accumulation of acids. Continuous feeding of both glucose and tryptone led to a further sixfold increase in production. In addition to enhancing production 25-fold, the efficiency of enzyme production and the specific activity of the excreted enzyme were also improved by glucose and tryptone feeding. These results demonstrate that in addition to genetic manipulations, optimization of cultivation conditions can lead to significant improvements in the production of heterologous proteins from Streptomyces.

Aryldialkylphosphatase↗

PubMed1987

Cloning of two type II methylase genes that recognise asymmetric nucleotide sequences: FokI and HgaI.

The modification genes of Flavobacterium okeanokoites and Haemophilus galinarum have been cloned into the vector pBR322 and expressed in Escherichia coli cells. FokI methylase gene is contained on a 3.80 kb piece of F. okeanokoites DNA. Plasmid constructs carrying this fragment of DNA are resistant to digestion by FokI restriction endonuclease but are sensitive to cleavage by HindIII, EcoRI and PstI. Unmodified lambda DNA molecules, exposed in vitro to cell extracts prepared from cells habouring this plasmid, became resistant to digestion by FokI. The smallest HgaI methylase clone carries the pBR322 plasmid containing a 3.50 kb piece of H. galinarum DNA. This plasmid is resistant to digestion by HgaI. Neither the FokI nor the HgaI restriction endonuclease was detected in either clone. This is the first report of cloning modification genes whose protein products recognise asymmetric nucleotide sequences.

Cloning, Molecular↗

PubMed1976

Localization of selenium in bacterial cells using TEM and energy dispersive X-Ray analysis.

Bacteria isolated from lake sediment samples reduced sodium selenite to elemental selenium. Finestructural observations were made on a number of different bacterial species cultured in the presence of sodium selenite. Examination of Escherichia coli and a Pseudomonas species revealed electron-dense deposits of irregular shape, composed of smaller units, within the cytoplasm but not on the cell wall and cell membrane. Cells of Aeromonas and Flavobacterium species exhibited conspicuous intranuclear fibrillary aggregates and different electron-dense inclusions. It appeared that the membrane structures were somewhat more easily stained in some bacterial cells after growth on agar plates containing sodium selenite. The deposits and fibrillary accumulations were interpreted to contain selenium on the basis of energy dispersive X-ray analysis. Control preparations and cells grown in the presence of sodium selenate were void of any fine-structural abnormalities. Alterations in fine structure are discussed in relation to the metabolism of selenium by bacterial cells and possible sites of inhibition.

Aeromonas↗

PubMedDate not supplied

Anti-pseudomonal activity of HR 810.

The anti-pseudomonal activity of HR 810, a new 2-aminothiazolyl cephalosporin, was compared to that of carbenicillin, azlocillin and cefsulodin against 187 non-fermenters. HR 810 was the best agent against Pseudomonas aeruginosa, Pseudomonas putida, Pseudomonas fluorescens and Acinetobacter calcoaceticus with an MIC50 less than or equal to 4 mg/l and an MIC90 less than or equal to 16 mg/l. It was as effective as azlocillin against Pseudomonas stutzeri and Pseudomonas mendocina, with an MIC50 less than or equal to 0.25 mg/l and an MIC90 less than or equal to 1 mg/l. It was not active against other species of Pseudomonas or other non-fermenters such as Flavobacterium sp.

Acinetobacter↗

PubMed1978

Bacterial utilization of cyclo(glycl-L-prolyl).

3 strains of soil bacteria (2 Achromobacter, 1 Flavobacterium) were isolated by growth on cyclo(Gly-L-Pro) as carbon/nitrogen source. Good growth required yeast extract supplements. Utilization of cyclo(Gly-L-Pro) was inducible. Many efforts failed to obtain active cell-free preparations. Injected radioactive cyclo(Gly-L-Pro) was excreted intact by the albino rat; in contrast, injected radioactive H-Gly-L-Pro-OH was extensively metabolized.

Dipeptides↗

PubMed1995

Preparation of deglycosylated egg white avidin.

A simple procedure for the preparation of deglycosylated avidin is described. Commercially obtained avidin was treated with a mixed microbial culture. The cells were capable of growing on the oligosaccharide residues, but generally ignored the polypeptide portion of the egg white glycoprotein. The resultant deglycosylated avidin retained its biotin-binding characteristics. The major bacterial strain (strain BECH080), responsible for the deglycosylation, was isolated. On the basis of elementary biochemical tests, fatty acid, and phenotypic analyses, the isolate was identified as a strain of Flavobacterium meningosepticum. The primary enzymatic activity that caused the removal of the oligosaccharide residues of avidin appeared to be similar to endoglycosidase F.

Avidin↗

PubMedDate not supplied

Large scale preparation and characterization of mucopolysaccharase contamination free heparinase.

By a combination of hydroxylapatite chromatography and negative adsorption on QAE-Sephadex at pH 8.3, heparinase (E.C.4.2.2.7) can be successfully isolated from all the other mucopolysaccharase contaminants present in Flavobacterium heparinum. Hydroxylapatite isolates heparinase primarily from chondroitinases, hyaluronidase, and most glycuronidases. QAE-Sephadex chromatography at pH 8.3 further separates heparinase from heparitinases, sulfatases, and the remaining glycuronidases. The heparinase preparation thus obtained contains no statistically significant levels of other contaminating mucopolysaccharases except for heparitinases that are present at an apparent maximum level of 3.4%. Owing to the presence of a crossreaction of heparinase on heparitin sulfate at conditions employed for the assay of heparitinase, the heparitinase level of 3.4% could be misleading because of the action of heparinase on heparitin sulfate. Characterization of this heparinase preparation shows that the enzyme has an optimum salt concentration of 0.08M NaCl, an optimum pH of 6.5, an activation energy of 5 kcal/mol, and a Km of 7.95 X 10(-6) M. These parameters are almost identical to those displayed by a homogeneous heparinase preparation. The method described here is suitable for scale-up purposes using batch chromatographic procedures.

Chromatography, Gel↗

PubMed1984

An immobilized microbial heparinase for blood deheparinization.

A new medical application of an immobilized microbial enzyme is described. Extracorporeal devices require systemic heparin administration to prevent thrombus formation; however, the use of heparin often leads to serious hemorrhagic complications. Heparinase isolated from Flavobacterium has been immobilized and used in a fluidized bed reactor to eliminate heparin from blood passing through an extracorporeal circuit both in vitro and in vivo. This paper discusses the stepwise development of this heparinase reactor including: (1) improvements in the fermentation resulting in an inexpensive large-scale source of heparinase without the addition of the previously required inducer, heparin; (2) the use of batch processes to adapt previous purification schemes to large-scale heparinase production and the subsequent purification of heparinase to a single SDS-PAGE banding protein; (3) the immobilization of heparinase with a 91% activity recovery and good stability, (4) the design and successful testing of a fluidized bed reactor containing immobilized heparinase in the removal of clinically used quantities of heparin from both human blood in vitro and canine blood in vivo; and (5) the initiation of animal studies focusing on the toxicology of heparinase-derived heparin degradation products and the short and long term effects of exposure to these products and to heparinase.

Enzymes, Immobilized↗

PubMed1997

Degradation of commercial detergent products by microbial populations of the Lagos lagoon.

The biodegradability potentials of three detergent products with the trade names Omo, Teepol and sodium dodecyl sulfate (SDS) by the native bacteria of the Lagos lagoon was carried out using the lagoon die-away method. Physicochemical parameters of the water samples showed that the lagoon in Apapa was more polluted than at the University of Lagos. In 12 days, approximately 30, 60 and 97% of Omo, Teepol and SDS respectively were degraded. SDS with an alkyl sulfate moiety as surfactant supported the highest growth of the detergent-utilizing organisms, indicating that the components of Omo and Teepol are more resistant to microbial attack. The detergent-utilizing bacteria identified were mainly Gram-negative and of the following genera: Vibrio, Klebsiella, Flavobacterium, Pseudomonas, Escherichia, Enterobacter, Proteus, Shigella and Citrobacter. Vibrio was the most frequently encountered organism while Proteus was the rarest. Results of this investigation had shown that detergents made in Nigeria may still contain components that are recalcitrant to biodegradation.

Bacillus↗

PubMed2005

Impact of non-Legionella bacteria on the uptake and intracellular replication of Legionella pneumophila in Acanthamoeba castellanii and Naegleria lovaniensis.

In aquatic environments, Legionella pneumophila survives, in association with other bacteria, within biofilms by multiplying in free-living amoebae. The precise mechanisms underlying several aspects of the uptake and intracellular replication of L. pneumophila in amoebae, especially in the presence of other bacteria, remain unknown. In the present study, we examined the competitive effect of selected non-Legionella bacteria (Escherichia coli, Aeromonas hydrophila, Flavobacterium breve, and Pseudomonas aeruginosa) on the uptake of L. pneumophila serogroup 1 by the amoebae Acanthamoeba castellanii and Naegleria lovaniensis. We also investigated their possible influence on the intracellular replication of L. pneumophila in both amoeba species. Our results showed that the non-Legionella bacteria did not compete with L. pneumophila for uptake, suggesting that the amoeba hosts took in L. pneumophila through a specific and presumably highly efficient uptake mechanism. Living and heat-inactivated P. aeruginosa best supported the replication of L. pneumophila in N. lovaniensis and A. castellanii, respectively, whereas for both amoeba species, E. coli yielded the lowest number of replicated L. pneumophila. Furthermore, microscopic examination showed that 100% of the A. castellanii and only 2% of the N. lovaniensis population were infected with L. pneumophila at the end of the experiment. This study clearly shows the influence of some non-Legionella bacteria on the intracellular replication of L. pneumophila in A. castellanii and N. lovaniensis. It also demonstrates the different abilities of the two tested amoeba species to serve as a proper host for the replication and distribution of the human pathogen in man-made aquatic environments such as cooling towers, shower heads, and air conditioning systems with potential serious consequences for human health.

Acanthamoeba castellanii↗