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Purification and properties of a beta-1,6-clucosidase from Flavobacterium.

An intracellular beta-1,6-glucosidase (beta-D-glucoside glucohydrolase, EC 3.2.1.21) was produced semiconstitutively by Flavobacterium M64. This enzyme was purified 180-fold by fractionation with ammonium sulfate followed by chromatographies on carboxymethylcellulose, hydroxyapatite and Sephadex G-100. The final preparation appeared homogeneous on disc electrophoresis on polyacrylamide gel. The molecular weight of the enzyme was determined to be ca. 59 000 by Sephadex G-100 gel filtration and sodium dodecylsulfate-polyacrylamide gel electrophoresis. The optimum pH of the enzyme was 5.8 and the optimum temperature was 40 degrees C. The enzyme readily hydrolyzed oligomers with beta-a,6-glucosidic linkages, converting them to glucose. The Km values for gentio-biose, -triose, -tetraose and -pentaose were 2.8, 3.0, 4.2 and 4.6 times 10- minus 4 M, respectively. The rates of their hydrolyses decreased with increase in their chain lengths. The enzyme was concluded to be a beta-1,6-glucosidase from its substrate specificity, production of glucose, transferring ability and inhibition by glucono-delta-lactone. The enzyme activity was inhibited by Hg-2+, Cu-2+, Ag-+, Fe-3+, p-chloromercuribenzoate, N-ethylmaleimide, glucose and trishydroxyaminomethane (Tris) but not by ethylenediaminetetraacetic acid.

Chromatography

On the structure of heparitin sulfates. Analyses of the products formed from heparitin sulfates by two heparitinases and a heparinase from Flavobacterium heparinum.

The analyses of the products formed from heparitin sulfates by the action of two heparitinases and a heparinase from Flavorbacterium heparinum is reported. Heparitin sulfates A and B are degraded by heparitinase I yielding two disaccharides, one of them composed of N-acetylucosamine and an unsaturated uronic, joined by alpha(1 lead to 4) linkage, and the other, with the same composition but with an O-sulfate at the hexosamine moiety. A third disaccharide is also formed from heparitin sulfate B, by the action of the same enzyme, composed of glucosamine N-sulfate and an unsaturated uronic acid joined probably by alpha(1 lead to 4) linkage. Besides these three disaccharides, heparitin sulfate B yields, by the action of heparitinase I, an oligosaccharide (with an average molecular weight of 6000) which is completely degraded by the heparitinase II yielding a disaccharide composed of glucosamine 2,6-disulfate and unsaturated uronic acid. All the disaccharides are further degraded by alpha-glycuronidase from Flavobacterium heparinum yielding the respective monosaccharides. Based on these and other analyses the possible structures of the heparitin sulfates are proposed.

Acetylglucosamine

Kinetic control of phosphoglycerate mutase from Flavobacterium sp. grown on ethylene glycol.

A species of Flavobacterium able to oxidise ethylene glycol to pyruvate via glyoxylate, glycerate, 2-phosphoglycerate and phosphoenolpyruvate exploits phosphoglycerate mutase to initiate gluconeogenesis. Partially purified phosphoglycerate mutase from this bacterium is independent of adenylate charge control but is activated by phosphoenolpyruvate. The possible significance of this regulation is discussed.

Acetyl Coenzyme A

A comparative study between a chondroitinase B and a chondroitinase AC from Flavobacterium heparinum: Isolation of a chondroitinase AC-susceptible dodecasaccharide from chondroitin sulphate B.

A chondroitinase that degrades only chondroitin sulphate B was isolated from Flavobacterium heparinum, and separated from a constitutive chondroitinase AC also present in extracts of F. heparinum. The enzyme acts only on chondroitin sulphate B, producing oligo- and tetra-saccharides, plus an unsaturated 4-sulphated disaccharide (deltaDi-4S). The oligosaccharide fraction (mol. wt. 3000) is susceptible to chondroitinase AC, producing mainly deltaDi-4S. The chondroitinase B is distinguished from chondroitinase AC by several properties, such as the effect of certain metal ions, temperature for optimal activity, and susceptibility to increasing salt concentrations. The enzyme is induced in F. heparinum by all the chondroitin sulphates, as well as by the disaccharides prepared from the chondroitins. The mechanism of induction of the enzyme and the structure of chondroitin sulphate B are discussed in relation to these results.

Anti-Bacterial Agents

Extracellular accumulation of a new amino acid, O-2-hydroxypropylhomoserine, from 1,2-propanediol by flavobacterium rigense.

During an investigation of microorganisms utilizing petrochemicals, a strain identified as Flavobacterium rigense was found to accumulate a new amino acid in a medium containing 1,2-propanediol as the sole carbon source. Cultural conditions for the accumulation of the product were investigated, and as a result, the yield was increased to 2.8 mg/ml after a 5-day incubation in a medium containing 8% 1,2-propanediol. The pure amino acid was isolated, and its structure was investigated. Elemental analysis and infrared, nuclear magnetic resonance, and mass spectral analyses indicated that the amino acids is O-2-hydroxypropylhomoserine.

Culture Media

Isolation and purification of Flavobacterium alpha-1,3-glucanase-hydrolyzing, insoluble, sticky glucan of Streptococcus mutans.

Studies were made on the physical and chemical properties of polysaccharides synthesized by cell-free extracts of Streptococcus mutans, Streptococcus sanguis, and Streptococcus sp. and their susceptibilities to dextranases. Among the polysaccharides examined, insoluble glucans were rather resistant to available dextranase preparations, and the insoluble, sticky glucan produced by S. mutans OMZ 176, which could be important in formation of dental plaques, was the most resistant. By enrichment culture of soil specimens, using OMZ 176 glucans as the sole carbon source, an organism was isolated that produced colonies surrounded by a clear lytic zone on opaque agar plates containing the OMZ 176 glucan. The organism was identified as a strain of Flavobacterium and named the Ek-14 bacterium. EK-14 bacterium was grown in Trypticase soy broth, and an enzyme capable of hydrolyzing the OMZ 176 glucan was concentrated from the culture supernatant and purified by negative adsorption on a diethylaminoethyl-cellulose (DE-32) column and gradient elution chromatography with a carboxymethyl-cellulose (CM-32) column. The enzyme was a basic protein with an isoelectric point of pH 8.5 and molecular weight of 65,000. Its optimum pH was 6.3 and its optimal temperature was 42 C. The purified enzyme released 11% of the total glucose residues of the OMZ 176 glucan as reducing sugars and solubilized about half of the substrate glucan. The products were found to be isomaltose, nigerose, and nigerotriose, with some oligosaccharides. The purified enzyme split the alpha-1,3-glucan endolytically and was inactive toward glucans containing alpha-1,6, alpha-1,4, beta-1,3, beta-1,4, and/or beta-1,6 bonds as the main linkages.

Cell-Free System

Purification and properties of elastolytic enzyme from Flavobacterium immotum.

Elastolytic enzyme was purified and crystallized from culture fluid of Flavobacterium immotum No. 9-35. The purified enzyme was homogeneous on polyacrylamide gel electrophoresis. The molecular weight was determined by Sephadex G-100 gel filtration to be 13,000. The isoelectric point was between pH 8.3 and 8.9. The optimum pH of the enzyme was 7.2 for elastolytic activity. The purified enzyme showed not only elastolytic activity, but also non-specific proteolytic activity against various other proteins. Milk-clotting activity was also observed. The enzyme did not act on keratin, collagen, or fourteen amino acid esters, including N-benzoyl-L-alanine methyl ester, N-benzoyl-L-arginine ethyl ester, and N-acetyl-L-tyrosine ethyl ester, which were typical substrates of pancreatic elastase [EC 3.4.21.11], trypsin [EC 3.4.21.4], and chymotrypsin [EC 3.4.21.1], respectively. However, the enzyme selectively hydrolyzed elastin when both elastin and albumin were present in the reaction mixture. The enzyme was inhibited by o-phenanthroline and various heavy metals such as cadmium, lead, zinc, and mercury. Various inhibitors, such as diisopropyl phosphofluoridate, tosyl-L-lysine chloromethyl ketone, tosyl-L-phenylalanine chloromethyl ketone, trypsin inhibitor, iodoacetamide, etc., had no effect on the elastolytic activity.

Animals

Chondroitinase C from Flavobacterium heparinum.

A chondroitinase that acts upon chondroitin sulfate C and hyaluronic acid was isolated from Flavobacterium heparinum. This enzyme was seperated from constitutional chondroitinase AC and an induced chondroitinase B also present in extracts of F. heparinum previously grown in the presence of chondroitin sulfates A, B or C. The enzyme acts upon chondroitin sulfate C producing tetrasaccharide plus an unsaturated 6-sulfated disaccharide (delta Di-6S), and upon hyaluronic acid producing unsaturated nonsulfated disaccharide (delta Di-OS). Chondroitin sulfate A is also degraded producing oligosaccharides and delta Di-6S but not delta Di-4S. The chondroitinase C is also distinguished from the chondroitinases B and AC by several properties, such as effect of ions, temperature for optimal activity, and susceptibility to increasing salt concentrations. The substrate specificity of the chondroitinase C is different from that of any other chondroitinase or hyaluronidase described so far.

Chondroitin Sulfates

Properties and biodegradation of a bioemulsifier from Corynebacterium hydrocarboclastus.

An extracellular polymer was produced by continuous fermentation of Corynebacterium hydrocarboclastus on kerosene in a 24 liter reactor. This polymer was composed of protein, lipid, and carbohydrates. The polymer possessed surface active properties, and had two critical micelle concentrations. Its effectiveness was quite comparable to the effectiveness of synthetic surface active agents such as Tween 80 and Span 20; however, its efficiency was much lower. The polymer also had emulsifying properties. Maximum emulsification was obtained at pH 6. The emulsifying properties were unaffected by high salt concentration [up to 5% (w/v) in Na+], and tolerated a water hardness up to 5,000 ppm. A 2 hr treatment of the polymer at temperatures higher than 65 degrees C resulted in a loss of its emulsifying properties. Two microorganisms, named SLYS and Y, isolated from soil, were able to grow on the polymer as sole carbon and energy source, thus proving its biodegradability. SLYS was tentatively identified as Flavobacterium breve and Y as Flavobacterium devorans.

Bacterial Proteins

Action of chondroitinases. I. The mode of action of two chondroitinase-AC preparations of different origin.

The modes of action of two chondroitinases-AC [EC 4.2.2.5] from Arthrobacter aurescens and Flavobacterium heparinum were examined. By comparison of the increase of viscosity and by analyses of digests using paper chromatography and gel filtration, it was shown that the Arthrobacter enzyme (A-Chase) degrades the substrate by a stepwise attack, while the Flavobacterium enzyme (F-Chase) exhibits a more random attack, though the first attack of both enzymes is of endo-type. Further study was carried out of the initial rate and final extent of the enzymic degradation of various mucopolysaccharides. The order of the initial rates at which the native mucopolysaccharides are degraded was similar for both enzymes. For A-Chase, the initial rate and final extent of degradation of modified chondroitin sulfate C or chondroitin methyl ester, however, were low compared with those of F-Chase. These results also suggested that A-Chase degrades the substrate by stepwise attack and F-Chase by random attack.

Arthrobacter

Serum bactericidal activity in the horseshoe crab, Limulus polyphemus.

Serum from the horseshoe crab, Limulus polyphemus, was examined for bactericidal activity against five species of bacteria. Greatest activity was found against Pseudomonas putida and Flavobacterium sp.; with the former, serum dilutions as high as 1:20 were capable of reducing viable counts by 50% within 2 h. Bactericidal activity of a significantly lesser magnitude was demonstrated against Serratia marcesencs and Salmonella minnesota. No killing was seen when the lobster pathogen Aerococcus viridans (formerly Gaffkya homari) was used. The cidal activity against Flavobacterium sp. remained relatively consistent for 6 months.

Animals

The history, biology, and taxonomy of the Cytophaga group.

The first section of this review covers the important characteristics of the genera Cytophaga and Sporocytophaga. The topics discussed include vegetative cell structure, the spreading habit, and degradation of macromolecules. A historical account of these two genera follows, together with a discussion on the definition of, and species differentiation with the genus Cytophaga, and on the taxonomy of Sporocytophaga. The third section deals with the relationships of the cytophagas with the flavobacteria and includes a brief history of Flavobacterium, reassignation of some species to Cytophaga, differentiation from Cytophaga, and a discussion on the definition of the genus Flavobacterium. This is followed by a section dealing with the relationship of Cytophaga with the flexibacteria, starting with an introduction to the diversity of flexing organisms and taxonomic developments, and proceeding with the differentiation within the family Cytophagaceae, and species differentiation in Flexibacter. The concluding section includes a proposed redefinition of Cytophaga, a proposal regarding species conservation in this genus, and discussions on the relationship between the cytophagas and the myxobacteria and on the significance of cytophagas in the environment. The characteristics of all described species of Cytophaga, Flexibacter, and relevant flavobacteria are tabulated and a bibliography is presented.

Bacteriology