PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “FLAVOBACTERIUM”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 289 records · Page 16Linked to original sources

Reichenbachia agariperforans gen. nov., sp. nov., a novel marine bacterium in the phylum Cytophaga-Flavobacterium-Bacteroides.

A heterotrophic, pigmented, agarolytic, gliding bacterium was isolated from a seawater sample collected from the Gulf of Peter the Great, Sea of Japan, during June 2000. 16S rDNA sequence analysis indicated that the novel bacterium, strain KMM 3525T, was a member of the phlyum Cytophaga-Flavobacterium-Bacteroides. On the basis of phenotypic, chemotaxonomic, genotypic and phylogenetic data, it is proposed that the marine bacterium represents the sole species of a novel genus, Reichenbachia, the type species of which is Reichenbachia agariperforans (KMM 3525T =IFO 16625T =JCM 11238T).

Bacteroides↗

Crystallization and preliminary analysis of chondroitinase AC from Flavobacterium heparinum.

Chondroitinase AC (E.C. 4.2.2.5) overexpressed in its host, Flavobacterium heparinum, was crystallized by vapor diffusion using polyethylene glycol methyl ether as precipitant. It crystallizes in the space group P43212 or its enantiomorph with a = b = 87.1 and c = 193.1 A and one molecule in the asymmetric unit. Crystals diffract to a maximum of 2.5 A resolution on a rotating-anode source. Screening for heavy-atom derivatives identified a lead compound that binds to a single site on the protein. Further screening is in progress.

Binding Sites↗

Crystallization and preliminary X-ray analysis of chondroitinase B from Flavobacterium heparinum.

Chondroitinase B, a glycosaminoglycan lyase from Flavobacterium heparinum, has been crystallized by hanging-drop vapor diffusion in space group P21 with unit-cell parameters a = 50.6, b = 74.5, c = 58. 7 A, beta = 92.9 degrees and one molecule in the asymmetric unit. This enzyme degrades dermatan sulfate, a glycosaminoglycan primarily made up of a disaccharide repeating unit of iduronic acid and N-acetylgalactosamine. A complete native data set has been collected from a single crystal to 2.2 A resolution using a rotating-anode source.

Chondroitin ABC Lyase↗

Purification and crystallization of precursors and autoprocessed enzymes of Flavobacterium glycosylasparaginase: an N-terminal nucleophile hydrolase.

Glycosylasparaginase (GA) represents a novel group of proteins that are activated by self-catalyzed peptide-bond cleavage from a single-chain precursor to yield the two subunits required for hydrolase activity. The wild-type GA precursor autoproteolyzes spontaneously into alpha and beta subunits. Strategies are reported here for purification to homogeneity of GA from Flavobacterium meningosepticum in both single-chain precursor and mature (autoprocessed) forms. The recombinant proteins crystallize in different space groups: P1 and P2(1) for the precursor and mature enzymes, respectively. The precursor crystals diffract to 1.9 A resolution with laboratory X-ray radiation.

Aspartylglucosylaminase↗

Chemical composition of Streptococcus mutans cell walls and their susceptibility to Flavobacterium L-11 enzyme.

The susceptibility to a cell wall lytic L-11 enzyme from Flavobacterium sp. and the quantitative and/or qualitative composition of the cell walls of some strains of cariogenic Streptococcus mutans and a non-cariogenic strain of Streptococcus mitis were determined. The purified cell walls of S. mutans strains HS-1 (serotype a), BHT (b), NCTC10449 (c), C67-1 (c), C67-25 (c), OMZ 176 (d), MT703 (e), MT557 (f), OMZ65 (g), and AHT (g), and S. mitis CHT contained glutamic acid, alanine, and lysine as well as muramic acid and glucosamine as a peptidoglycan component. Besides these amino acids, significant amounts of threonine were detected in strains HS-1, OMZ65, and AHT cell walls, and considerable amounts of aspartic acid and/or threonine as well as several other amino acids in OMZ176, OMZ65, and CHT cell walls. Rhamnose was a common special component of the cell walls of S. mutans strains BHT, NCTC10449, MT703, B2 (e), MT557, and AHT, and S. mitis CHT. An additional sugar component, glucose, was detected in the cell walls of all of these strains except BHT, and galactose was found in BHT, AHT, and CHT cell walls. Galactosamine was present in S. mitis CHT cell walls. Varying amounts of phosphorus were detected in the cell walls of all the strains examined. The cell walls of all these streptococcal strains except MT703, 6715, and AHT were susceptible to the lytic action of the L-11 enzyme to various extents. No consistent relationship was observed between the amino acid and sugar composition of these cell walls and their susceptibility to the L-11 enzyme. The chemical composition of these cell walls is discussed in terms of the serological classification of S. mutans.

Amino Acids↗

Biological activities of partially purified elastase produced by Flavobacterium meningosepticum.

Injection of viable cells of Flavobacterium meningosepticum at doses of 10(6) colony-forming units/eye caused ophthalmia in rabbits' corneas. Elastase, free of protease activity, was partially purified from broth cultures of F. meningosepticum ATCC12535 and TMS516. The optimum pH of the elastase activity was about 8.0. The activity was suppressed by Ni, Zn, Co, EDTA, and o-phenanthroline, and accelerated by Cu and Fe. The minimum dose of the elastase causing ophthalmia in the eyes of rabbits was 5 micrograms/eye (0.065 elastase units). The minimum lethal dose of the elastase for suckling mice by intracerebral injection was 0.4 micrograms (0.0052 elastase units)/suckling mouse, and its minimum lethal dose for adult mice by intraperitoneal injection was 740 micrograms/mouse (9.52 elastase units).

Animals↗

Adjuvanticity of an ornithine-containing lipid of Flavobacterium meningosepticum as a candidate vaccine adjuvant.

Ornithine-containing lipids (OrnL) extracted from Flavobacterium meningosepticum have been reported to have various biological activities such as B-cell mitogenicity and macrophage activation to generate interleukin-1 and prostaglandin E2. We, using ovalbumin (OVA) as an antigen, evaluated the adjuvant activity of OrnL as an immunological adjuvant in BALB/c mice. OrnL showed the function of forming liposome-like vesicles retaining biological activities when prepared as either small unilamellar or dehydration-rehydration vesicles. Although OrnL was not shown to have enough entrapping efficacy for use as a vaccine adjuvant, phosphatidylglycerol (PG) and cholesterol (CHOL) added to stabilize the vesicle membrane increased the entrapping efficacy to the same extent as that of conventional liposomes. Furthermore, the stabilized OrnL vesicles tolerated centrifugation to remove non-entrapped antigens. Completely antigen-entrapped OrnL vesicles including Pg and CHOL induced a significantly greater enhancement of IgG antibody production than did aluminum hydroxide gel in BALB/c mice from week 6. These results indicate that OrnL can be utilized as an immunological adjuvant for vaccines.

Adjuvants, Immunologic↗

Changes in the cell structure of Flavobacterium psychrophilum with length of culture.

Flavobacterium psychrophilum, the pathogen of bacterial cold-water disease, causes serious problems in ayu Plecoglossus altivelis culture. This study investigated the effect of the culture period of F. psychrophilum and on the structure of its cells. From the SDS-PAGE of total proteins of cellular components, much difference was found between the 36 hr culture and the 48 and 72 hr cultures. A SEM observation of the cells showed many fragments, especially on the cell surface of the 36 hr culture. These fragments consisted of an outer membrane, seen by TEM observation, and may contain substances causing the virulence. Specific proteins observed by the SDS-PAGE and fragments in the 36 hr culture may be related to the virulence of F. psychrophilum.

Animals↗

A note on a selective agar medium for the enumeration of Flavobacterium species in water.

A selective nutrient agar medium containing kanamycin at 50 micrograms/ml was developed for the isolation and enumeration of yellow-pigmented colonies from the River Sowe, Coventry. Such organisms were shown to be members of the heterogeneous genus Flavobacterium. Typically, yellow pigmented colonies constituted less than 10% of the colonies on nutrient agar alone but up to 70% on nutrient agar plus kanamycin. This medium is a useful addition to the range of media available for the isolation and further ecological study of particular species of this important group of micro-organisms.

Agar↗

Identification and distribution of Flavobacterium meningosepticum in clinical material.

During the 19 year period ending December 1984, 82 (1.7%) of 4840 strains of Gram-negative non-fermentative bacteria submitted to the National Collection of Type Cultures (NCTC) for computer-assisted identification were Flavobacterium meningosepticum. These figures suggest either that F. meningosepticum occurs only rarely in clinical material in the UK, or that when it does occur it is not always recognized. The sources from which the NCTC strains were isolated are reported and also the characteristics by which the species may be identified. The clinical significance of F. meningosepticum is reviewed, particularly its role in neonatal meningitis, of which there have been but two reported cases in the UK, both imported. The susceptibility of the species to antimicrobial agents is discussed and also antimicrobial therapy of neonatal meningitis due to this species.

Adult↗

Factorial analysis of tricarboxylic acid cycle intermediates for optimization of zeaxanthin production from Flavobacterium multivorum.

AIMS: To study the effect of intermediates of the tricarboxylic acid (TCA) cycle on the production of zeaxanthin from Flavobacterium multivorum in order to optimize production of this xanthophyll carotenoid. METHODS AND RESULTS: The concentration of selected TCA cycle intermediates (malic acid, isocitric acid and alpha-ketoglutarate) was optimized in shake flask culture, using a statistical two-level, three-variable factorial approach. The carotenoid production profile was also studied in the optimized medium at various growth phases. Optimized medium resulted in a sixfold increase in volumetric production of zeaxanthin (10.65 +/- 0.63 microg ml-1) using malic acid (6.02 mm), isocitric acid (6.20 mm) and alpha-ketoglutarate (0.02 mm). The majority of zeaxanthin was produced in the late logarithmic growth phase whereas a substantial amount of beta-cryptoxanthin and beta-carotene were observed in the early logarithmic phase. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrates improvement of zeaxanthin production from F. multivorum which might aid in the commercialization of zeaxanthin production from this microbe.

Bioreactors↗

Genetic fingerprinting of Flavobacterium columnare isolates from cultured fish.

AIMS: To evaluate the intraspecific diversity of the fish pathogen Flavobacterium columnare. METHODS AND RESULTS: Genetic variability among Fl. columnare isolates was characterized using restriction fragment length polymorphism analysis of the 16S rDNA gene, intergenic spacer region (ISR) sequencing, and amplified fragment length polymorphism (AFLP) fingerprinting. Thirty Fl. columnare cultures isolated from different fish species and geographical origins as well as reference strains were included in the study. Fifteen isolates belonged to genomovar I while eleven were ascribed to genomovar II. Analysis of the ISR sequence confirmed the genetic differences between both genomovars but revealed a higher diversity among genomovar I isolates. The maximum resolution was provided by AFLP fingerprinting, as up to 22 AFLP profiles could be defined within the species. CONCLUSIONS: We confirmed the division of Fl. columnare isolates from cultured fish into different genogroups. We showed that both genomovars I and II are present in channel catfish from the US. We described a unique genetic group represented by four Fl. columnare isolates from tilapia in Brazil which appears to be related to both genomovars. We were able to further subdivide the species by analysing the ISR. Finally, the use of AFLP allowed us to fingerprint the species at clone level without losing the higher genetic hierarchy of genomovar division. SIGNIFICANCE AND IMPACT OF THE STUDY: This paper reports on an extensive assessment of the use of molecular tools for the study of the epidemiology of the fish pathogen Fl. columnare.

Animals↗

Identification of P18, a surface protein produced by the fish pathogen Flavobacterium psychrophilum.

AIMS: This study was focused on the identification of associated outer membrane proteins which may play a role in the specific interactions between Flavobacterium psychrophilum (the aetiological agent of cold-water disease and rainbow trout fry syndrome in salmonid fish worldwide) and the fish tissues. METHODS AND RESULTS: The surface protein interactions with the outer membrane being mainly ionic, different methods were used for the detachment of proteins from the cell surface of Fl. psychrophilum involving detergent-free buffers or solutions known to perturb the ionic interactions. Such treatments led to the isolation of a surface protein, named P18 in accordance with its relative molecular mass. The expression of P18 was not related to the growth conditions (liquid or solid medium, temperature and aeration) or the strains of Fl. psychrophilum tested here. CONCLUSIONS: Preliminary characterization indicated that P18 is a surface antigen which is not sugar-modified and might be a subunit of a surface layer (i.e. S-layer), one of the most common surface structures on bacteria. SIGNIFICANCE AND IMPACT OF THE STUDY: Data reported here should be used as the basis for further works involving the purification and characterization of P18 to identify the specific roles of such a surface protein, especially the interaction between this protein and the host surface.

Animals↗

Sensitive and rapid detection of Flavobacterium columnare in channel catfish Ictalurus punctatus by a loop-mediated isothermal amplification method.

AIMS: To evaluate the loop-mediated isothermal amplification method (LAMP) for rapid detection of Flavobacterium columnare and determine the suitability of LAMP for rapid diagnosis of columnaris infection in channel catfish, Ictalurus punctatus. METHODS AND RESULTS: A set of four primers, two outer and two inner, were designed specifically to recognize 16S ribosomal RNA gene of this pathogen. Bacterial genomic DNA templates were prepared by hot lysis in a lysis buffer. Amplification of the specific gene segments was carried out at 65 degrees C for 1 h. The amplified gene products were analysed by agarose gel electrophoresis and detected by staining gels with ethidium bromide. A PCR assay was also included in this study. Our results demonstrate that the ladder-like pattern of bands from 204 bp specific to the Fl. columnare 16S ribosomal RNA gene was amplified. The detection limit of the LAMP assay was comparable to that of PCR in prepared genomic DNA reactions. In addition, this optimized LAMP assay was able to detect the Fl. columnare 16S ribosomal RNA gene in experimentally infected channel catfish. CONCLUSIONS: The LAMP assay for Fl. columnare detection in channel catfish was established. SIGNIFICANCE AND IMPACT OF THE STUDY: Because LAMP assay is a rapid, sensitive, specific, simple and cost-effective assay for Fl. columnare detection in channel catfish, it is useful for rapid diagnosis of Fl. columnare in fish hatcheries and the field.

Animals↗

Systemic and mucosal antibody response in tilapia, Oreochromis niloticus (L.), following immunization with Flavobacterium columnare.

Specific antibody responses to Flavobacterium columnare (isolate ATCC 23463T) were characterized in plasma and mucus of tilapia following intraperitoneal (i.p.) injection or immersion immunization with formalin-killed sonicated or whole cell preparations. Fish (30 per treatment) received a primary immunization and were booster immunized 4 weeks later. An enzyme-linked immunosorbent assay was developed for detection and quantification of specific anti-F. columnare antibody, and it was found that formalin-killed sonicated cells in Freund's complete adjuvant (FCA) injected i.p. stimulated a significant systemic antibody response within 2 weeks (mean titre 11,200) which increased to 30,600 following secondary immunization. At 10 weeks post-immunization, the mean titre remained significantly elevated above the controls. Antibodies were also observed in cutaneous mucus of fish immunized i.p. with formalin-killed sonicated cells in FCA at 6 and 8 weeks post-immunization (mean titres 67 and 33, respectively). Although some individual fish responded, mean plasma and cutaneous mucus antibody titres were not significantly greater than controls in any of the other treatment groups. The results of this study demonstrate that tilapia can mount a significant humoral response in plasma and cutaneous mucus to F. columnare, but i.p. immunization with FCA is required to elicit this response.

Animals↗

Characterization of two membrane-associated protease genes obtained from screening out-membrane protein genes of Flavobacterium columnare G4.

In order to identify genes encoding the outer membrane proteins (OMPs) of the myxobacter Flavobacterium columnare G(4), the expression library of the bacterium was screened by using rabbit antisera developed against its OMPs. Positive colonies of Escherichia coli M15 containing fragments encoding the bacterial OMPs were selected for cloning the relevant genes by genomic walking methods. Two genes encoding a membrane-associated zinc metalloprotease and prolyl oligopeptidase are reported in this paper. The membrane-associated zinc metalloprotease gene (map) is 1800 bp in length, coding for 449 amino acids (aa). Despite the presence of a conserved motif HEXXH for all metalloproteases, the special HEXXH approximately 32 aa approximately E motif of the F. columnare G(4) Map and its low level of identity with other reported zinc-containing metalloproteases may imply that the membrane-associated zinc metalloprotease of F. columnare G(4) represents a new family of zincins. The gene encoding prolyl oligopeptidase (Pop), a serine proteinase, is 2352 bp in length, coding for 649 aa. Sequence homology analysis revealed that the Pop is also novel as it has < 50% identity with other reported prolyl oligopeptidase family proteins. The present study represents the first to employ anti-fish bacterial OMP sera to screen genes of membrane-associated proteases of fish pathogenic bacteria, and to provide necessary information for the examination of the role of the two genes in the infection and pathogenesis of F. columnare.

Amino Acid Motifs↗

Isolation and characterization of strains of Flavobacterium columnare from Brazil.

Flavobacterium columnare is an important pathogen of freshwater fish, implicated in skin and gill disease, often causing high mortality. An outbreak of skin disease in fingerling and adult Nile tilapia, Oreochromis niloticus (L.), cultivated in a recirculation system, was investigated. Four strains were isolated and characterized by biochemical reactions, enzyme production, fatty acid profile and analysis of the 16S-23S rDNA intergenic spacer region. All strains were identified as F. columnare. Experimental infection assays with one of these strains (BZ-5-02) were conducted and pathogenicity (by intramuscular route) was demonstrated in Nile tilapia and channel catfish, Ictalurus punctatus (Rafinesque). This is the first report of characterization of Brazilian strains of F. columnare.

Animals↗

Influence of rearing conditions on Flavobacterium columnare infection of rainbow trout, Oncorhynchus mykiss (Walbaum).

The influence of rearing conditions on Flavobacterium columnare infection of rainbow trout, Oncorhynchus mykiss (Walbaum), was studied experimentally in the laboratory and at a fish farm. In experiment I, the effect of parasitic infection on columnaris disease was studied using F. columnare carrier fish. The fish were exposed to Diplostomum spathaceum cercariae and a set of other stressors in order to induce clinical columnaris infection. Parasitic infection and other stressors failed to induce the disease. Disease occurred when the fish were challenged with F. columnare, but D. spathaceum infection did not enhance the severity of the infection. In experiment II, the influence of rearing density and water temperature was studied. Overall mortality was highest in fish at normal rearing density with high temperature (+23 degrees C). At low temperature (+18 degrees C) mortality was not affected by rearing density, but the transmission of columnaris disease was faster at normal rearing density at both temperatures. This supports the view that reduction of fish density could be used in prevention of columnaris disease especially if water temperature is high. Because the lower rearing density can also decrease the transmission of ectoparasites and penetrating endoparasites, it could be an efficient tool in ecological disease management.

Analysis of Variance↗