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Multilocus enzyme electrophoresis of Clostridium argentinense (Clostridium botulinum toxin type G) and phenotypically similar asaccharolytic clostridia.

Twenty-three strains of Clostridium argentinense, C. subterminale, C. hastiforme, and other phenotypically similar asaccharolytic clostridia recently placed in seven DNA hybridization groups were compared by multilocus enzyme electrophoresis. The three nontoxigenic strains of C. argentinense were most closely related to the toxigenic strains of this species. All nine toxigenic strains of C. argentinense belonging to a single DNA hybridization group had identical enzyme types on the basis of nine enzymes. All other strains except for two derived from the type strain of C. subterminale were differentiable. Overall, there was excellent agreement between DNA relatedness and multilocus enzyme electrophoresis results.

Clostridium↗

[Antagonistic effect against "Clostridium perfringens" exerted in the digestive tract of gnotobiotic mice by "Clostridium" strains isolated from the microflora of conventional mice (author's transl)].

Bacterial strains isolated from the digestive tract of conventional mice produced a barrier effect against a strain of Clostridium perfringens type A (strain CP) in the gastrointestinal tract of gnotobiotic mice. This barrier effect was observed when mice, monoassociated with Escherichia coli K12, were inoculated with a mixed culture of fusiform-shaped clostridia. The collection of fusiforms (collection D) was obtained from a single colony chosen from among the 26 types studied. Collection D and E. coli K12 together exerted a barrier effect against all strains of C. perfringens type A tested. No effect was observed against a C. perfringens type C strain. The expression of the barrier effect depended on the order in which the strains were used to inoculate the mice. Thus strain CP was eliminated from the digestive tract when the mice had previously been associated with collection D and E. coli K12. If the mice were inoculated with strain CP first, however, the barrier effect was only partial. We have also been able to use two strains of clostridia (C1, C3) instead of E. coli K12 to produce a drastic barrier effect against strain CP. The order in which the strains were used to inoculate the mice did not, in this case, influence the production of a barrier effect. Three strains (Da, Db, Dc) isolated from collection D, produced only a partial barrier effect against strain CP in mice previously associated with E. coli K12. These results illustrate the difficulties encountered in determining the minimal number of bacterial strains involved in the production of a barrier effect.

Animals↗

Selenium requirement for active xanthine dehydrogenase from Clostridium acidiurici and Clostridium cylindrosporum.

The xanthine dehydrogenase of Clostridium acidiurici and C. cylindrosporum was assayed with methyl viologen as acceptor. In C. acidiurici the basal activity level was about 0.3 mumol/min x mg of protein. Cells grown on uric acid in the presence of 10(-7) M selenite showed a 14-fold increase in xanthine dehydrogenase activity, which decreased with higher selenite concentrations (10(-5) M). The supplementation with 10(-7) M molybdate or tungstate was without effect. High concentrations of tungstate decreased the xanthine dehydrogenase if selenite was also present. In comparison, high concentrations of molybdate affected only a small decrease in activity level at the optimal concentration for selenite and relieved to some degree the inhibitory effect of 10(-5) M selenite. With hypoxanthine and xanthine as substrates for growth again only the addition of selenite was necessary to show a similar increase in xanthine dehydrogenase activity. C. acidiurici could be grown in a mineral medium. Both xanthine dehydrogenase and formate dehydrogenase exhibited the highest level of activity if selenite and tungstate were present in that medium. In C. cyclindrosporum the basal activity level of xanthine dehydrogenase was about 0.95 mumol/min x mg of protein. The addition of 10(-7) M selenite to the growth medium increased the activity level about 3-fold, but the highest level (3.7 U/mg) was reached if 10(-7) M molybdate was also added. The presence of tungstate resulted in a decreased enzyme activity.

Cell-Free System↗

Surface properties from the S-layer of Clostridium thermosaccharolyticum D120-70 and Clostridium thermohydrosulfuricum L111-69.

Labelling experiments using a positively charged topographical marker for electron microscopy, polycationized ferritin, showed that the S-layers of two closely related clostridia Clostridium thermohydrosulfuricum L111-69 and C. thermosaccharolyticum D120-70 do not exhibit a net negative charge, as usually observed for bacterial cell surfaces. Chemical modification of reactive sites confirmed that amino and carboxyl groups are exposed on the S-layer surface of both strains. Amino-specific, bifunctional agents crosslinked both S-layer lattices. Studies with carbodiimides revealed that only the S-layer surface of C. thermohydrosulfuricum L111-69 had amino and carboxyl groups closely enough aligned to permit electrostatic interactions between the constituent protomers. The regular structure of this S-layer lattice was lost upon converting the carboxyl groups into neutral groups by amidation. Disintegration of both S-layer lattices occurred upon N-acetylation or N-succinylation of the free amino groups. Adhesion experiments showed that in neutral and weakly alkaline environment whole cells of C. thermosaccharolyticum D120-70 exhibited a stronger tendency to bind to charged surfaces than whole cells of C. thermohydrosulfuricum L111-69, but showed a lower tendency to bind to hydrophobic materials.

Cell Wall↗

Differentiation between Clostridium acidiurici and Clostridium cylindrosporum on the basis of specific metal requirements for formate dehydrogenase formation.

The formate dehydrogenases of Clostridium acidiurici and of C. cylindrosporum coupled the oxidation of formate with the reduction of viologen dyes. The basal activity level was about 0.85 mumoles/min X mg of protein for both species. The level of formate dehydrogenase of C. acidiurici increased 12-fold when 10(-7) M tungstate and selenite were present during growth. Molybdate exerted no effect. On the other hand, molybdate and selenite were required to increase the formate dehydrogenase of C. cylindrosporum, and tungstate exhibitedan antagonistic effect in this organism. Growth on hypoxanthine generally depended on the addition of bicarbonate. Supplementation with tungstate and selenite accellerated growth of C. acidiurici and increased again the level of formate dehydrogenase. The addition of both, molybdate and selenite was necessary to initiate growth of C. cyclindrosporum and to form an active formate dehydrogenase. The differences in the requirement for metal ion supplementation to form high levels of formate dehydrogenase and their involvement in hypoxanthine degradation can be used to differentiate between C. acidiurici and C. cylindrosporum.

Aldehyde Oxidoreductases↗

N2 fixation and NH4+ assimilation in the thermophilic anaerobes Clostridium thermosaccharolyticum and Clostridium thermoautotrophicum.

Inorganic nitrogen metabolism in the obligate anaerobic thermophiles Chlostridium thermosaccharolyticum and Clostridium thermoautotrophicum differs in several respects. C. thermosaccharolyticum contains a nitrogenase as inferred from NH4+ repressible C2H2 reduction, a glutamine synthetase which is partially repressed by ammonium, very labile glutamate synthase activities with both NADH and NADPH, NADPH-dependent glutamate dehydrogenase, and NH4+-dependent asparagine synthetase. C. thermoautotrophicum contains no nitrogenase, but glutamine synthetase, no glutamate synthase, no glutamate dehydrogenase, but a NADH-dependent alanine dehydrogenase and a NH4+-dependent asparagine synthetase.

Alanine Dehydrogenase↗

Genetic interrelationships of proteolytic Clostridium botulinum types A, B, and F and other members of the Clostridium botulinum complex as revealed by small-subunit rRNA gene sequences.

The phylogenetic interrelationships of members of the Clostridium botulinum complex of species was investigated by direct sequencing of their 16S rRNA genes. Comparative analysis of the 16S rRNA sequences demonstrated the presence of four phylogenetically distinct lineages corresponding to: i) proteolytic C. botulinum types A, B, and F, and C. sporogenes, ii) saccharolytic types B, E and F, iii) types C and D and C. novyi type A, and iv) type G and C. subterminale. The phylogenetic groupings obtained from the 16S rRNA were in complete agreement with the four divisions recognised within the the 'species complex' on the basis of phenotypic criteria.

Base Sequence↗

Restriction endonuclease activity in Clostridium thermocellum and Clostridium thermosaccharolyticum.

Clostridium thermocellum cell extracts exhibit specific endonuclease activity with very little non-specific exonuclease activity at 55 degrees C. The Dam methylation system of Escherichia coli offers complete protection from digestion by C. thermocellum ATCC 27405 cell extracts for all DNA tested (totaling > 100 kb, insuring that most potential restriction sequences have been exposed). Based on both the Dam recognition sequence and the similarity of cell extract and MboI DNA digests, the C. thermocellum restriction enzyme recognition sequence appears to be 5' GATC 3'. Cell extracts made from a second thermophile, C. thermosaccharolyticum ATCC 31960 do not exhibit specific endonuclease activity under the conditions tested. Genomic DNA from C. thermocellum exhibits a Dam+ phenotype while genomic DNA from C. thermosaccharolyticum exhibits a Dam- phenotype.

Biotechnology↗

Nucleotide sequence of the gene coding for Clostridium botulinum (Clostridium argentinense) type G neurotoxin: genealogical comparison with other clostridial neurotoxins.

The neurotoxin gene from Clostridium botulinum type G was cloned as a series of overlapping DNA fragments generated using polymerase chain reaction (PCR) technology and primers designed to conserved regions of published botulinal toxin (BoNT) sequences. The 5'-end of the gene was obtained using a primer based on a conserved region of the nontoxic-nonhaemagglutinin gene lying upstream of the toxin gene. Translation of the nucleotide sequence derived from the cloned PCR fragments demonstrated that the gene encodes a protein of 1297 amino acid residues (rmm 149, 147). Comparative alignment of the determined BoNT/G sequence with those of other clostridial neurotoxins revealed highest sequence relatedness (approx. 58% amino acid identity) with BoNT/B of proteolytic and non-proteolytic C. botulinum. Tetanus toxin (TeTx) and other BoNT types revealed lower levels of relatedness with BoNT/G (approximate range 35-42% amino acid identity).

Amino Acid Sequence↗

Correlative properties for a differentiation of two Clostridium sordellii phenotypes and their distinction from Clostridium bifermentans.

As the present classification (19) of Clostridium sordellii and C. bifermentans is based on properties which are not conclusive for most of our strains, we investigated 80 strains from various origin of this group regarding 30 selected properties. Four of these properties were correlative and therefore particularly important for a distinct differentiation of the strains investigated: urease activity (U), growth inhibition by 1% mannose (M), arginine deaminase activity (A), and sialidase (EC 3.2.1.18) activity (S). Concerning these four characters three clusters were formed: cluster I was positive for U, M, A, and S and comprised 36 strains including C. sordellii type strain (ATCC 9714T); cluster II was positive for M and S and negative for U and A and comprised twelve strains including strain ATCC 35392; and cluster III was positive for A and negative for U, M, and S and comprised 32 strains including C. bifermentans type strain (ATCC 638T). Only two of the correlative properties (U and S, U and A, A and M, or A and S) needed to be tested to determine the affiliation of any strain of the C. sordellii/bifermentans group to one of the three clusters. Clusters I and II, representing two phenotypes of C. sordellii, can now clearly be distinguished from C. bifermentans. Sialidase formed by cluster I and II strains was inhibited by antibodies produced against cluster I strain sialidase. No cross reaction was found with other clostridial sialidases. Pathogenicity, hitherto considered as one of the distinctive properties of C. sordellii and C. bifermentans, was found with various strains of all the three clusters. Therefore, in the case of an infection caused by these two species, care should be taken as to the pathogenicity especially of C. bifermentans and treatment should be accordingly.

Animals↗

Identification of Clostridium butyricum and Clostridium beijerinckii by gas-liquid chromatography and sugar fermentation: correlation with DNA homologies and electrophoretic patterns.

Sixty-five strains of clostridia of the butyricum group were studied by DNA-DNA hybridization, electrophoresis of cell proteins, gas-liquid chromatography, and fermentation of glycerol, inositol and ribose. The DNA--DNA hybridization results confirmed that strains of this group belong to two main species, Clostridium butyricum and C. beijerinckii. Five strains did not hybridize with the reference strains of these two species. Most of the strains could be identified by quantitative gas-liquid chromatographic analysis combined with fermentation patterns. The other strains could be identified by their protein electrophoretic patterns.

Acetates↗

Effect of glucose concentration in the growth medium upon neutral and acidic fermentation end-products of Clostridium bifermentans, Clostridium sporogenes and peptostreptococcus anaerobius.

Clostridium bifermentans, C. sporogenes and Peptostreptococcus anaerobius were grown in Fastidious Anaerobe Broth with glucose concentrations from 0-1.5% (w/v). Gas chromatographic (GLC) analysis of fermentation end-products revealed that a change in glucose concentration markedly affected fermentation patterns of each microorganism. Increased glucose concentration resulted in stimulation of ethanol production by all strains, and of butanol and butyric acid by C. sporogenes. With C. bifermentans, there was a parallel increase in ethanol and acetic acid production and decreased formation of propanol and propionic, iso-butyric and iso-valeric acids. Increased ethanol formation by P. anaerobius was accompanied by an increase in acetic acid and a decrease in butan-1-ol production. The greatest incremental change in GLC profiles occurred when glucose concentration was raised from zero to 0.1% (w/v). These data suggest that glucose concentration in a medium for GLC analysis must be rigorously controlled if reproducible results are to be obtained.

Chromatography, Gas↗

Reinvestigation of the taxonomy of Clostridium bifermentans and Clostridium sordellii.

The taxonomic relationships between Clostridium bifermentans and C. sordellii were reinvestigated by numerical taxonomy, studies of DNA-DNA homology and DNA duplex thermal stability, and by analysis of cell-wall sugar components. Although the results indicate that both species may be grouped into one geno-species, C. sordellii strains could be differentiated from C. bifermentans strains on the basis of a few phenetic criteria that include the inability to ferment mannose and sorbitol, the absence of mannose in the cell wall, the production of urease, the absence of arginine deaminase activity, and susceptibility to inhibition of growth by mannose.

Arginase↗

Diversity in molecular mass of the common EDTA-soluble antigens of Clostridium chauvoei and Clostridium septicum.

Common EDTA-soluble antigens of Clostridium chauvoei and C. septicum were examined by indirect-immunofluorescence (IFA) and immunoblot analysis. The monoclonal antibodies (mAbs) specific for the 35 kDa antigen of C. chauvoei strain ATCC 10092 were used. These mAbs reacted with all 11 strains, 6 of C. chauvoei and 5 of C. septicum, in IFA. In immunoblot analysis with the mAbs, the bands at molecular mass of 35 kDa were found in all C. chauvoei strains, while the bands at 36 kDa were found in 4 of 5 strains of C. septicum. These results indicate that the 35 kDa antigen of C. chauvoei and the 36 kDa antigen of C. septicum possess a similar epitope recognized by the mAb.

Animals↗

Gene arrangement in the upstream region of Clostridium botulinum type E and Clostridium butyricum BL6340 progenitor toxin genes is different from that of other types.

The cluster of genes encoding the botulinum progenitor toxin and the upstream region including p21 and p47 were divided into three different gene arrangements (class I-III). To determine the gene similarity of the type E neurotoxin (BoNT/E) complex to other types, the gene organization in the upstream region of the nontoxic-nonhemagglutinin gene (ntnh) was investigated in chromosomal DNA from Clostridium botulinum type E strain Iwanai and C. butyricum strain BL6340. The gene cluster of type E progenitor toxin (Iwanai and BL6340) was similar to those of type F and type A (from infant botulism in Japan), but not to those of types A, B, and C. Though genes for the hemagglutinin component and P21 were not discovered, genes encoding P47, NTNH, and BoNT were found in type E strain Iwanai and C. butyricum strain BL6340. However, the genes of ORF-X1 (435 bp) and ORF-X2 (partially sequenced) were present just upstream of that of P47. The orientation of these genes was in inverted direction to that of p47. The gene cluster of type E progenitor toxin (Iwanai and BL6340) is, therefore, a specific arrangement (class IV) among the genes encoding components of the BoNT complex.

Botulinum Toxins↗

Construction of an Escherichia coli-Clostridium perfringens shuttle vector and plasmid transformation of Clostridium perfringens.

A stable shuttle vector which replicates in Escherichia coli and Clostridium perfringens was constructed by ligating a 3.6-kilobase (kb) fragment of plasmid pBR322 with C. perfringens plasmid pHB101 (3.1 kb). The marker for this shuttle plasmid originated from the 1.3-kb chloramphenicol resistance gene of plasmid pHR106. The resulting shuttle vector, designated pAK201, is 8 kb in size and codes for resistance to 20 micrograms of chloramphenicol per ml in both E. coli and C. perfringens. Following shuttle vector construction in E. coli, plasmid pAK201 was transformed into E. coli HB101 and C. perfringens ATCC 3624A, using intact cell electroporation. The transformation frequencies were 10(6) and 10(4) transformants per microgram of DNA in E. coli and C. perfringens, respectively. Restriction enzyme analysis of the chimera isolated from transformants of both microorganisms suggested that the plasmids were identical. Reciprocal transformation experiments in E. coli and C. perfringens indicated no difference in transformation frequency. Plasmid pAK201 was stable in C. perfringens following repeated transfer in the absence of chloramphenicol pressure. The restriction map of plasmid pAK201 shows six unique cut sites which should be useful for future genetic analysis and C. perfringens gene library construction.

Chloramphenicol↗

Purification and properties of an acetoacetyl coenzyme A-reacting phosphotransbutyrylase from Clostridium beijerinckii ("Clostridium butylicum") NRRL B593.

During the study of acetoacetyl coenzyme A (CoA)-reacting enzymes of Clostridium beijerinckii NRRL B593, a phosphate-dependent acetoacetyl-CoA-utilizing activity was detected in protein fractions devoid of thiolase and phosphotransacetylase. Further purification of this acetoacetyl-CoA-utilizing activity yielded an enzyme which may be designated as phosphotransbutyrylase (PTB; phosphate butyryltransferase [EC 2.3.1.19]). PTB from C. beijerinckii NRRL B593 was purified 160-fold with a yield of 14% and, with the best fractions, purified 190-fold to near homogeneity. It showed a native Mr of 205,000 and a subunit Mr of 33,000. PTB activity was sensitive to pH changes within the physiological range of 6 to 8. PTB exhibited a broad substrate specificity. The Km values at pH 7.5 for butyryl-CoA, acetoacetyl-CoA, and acetyl-CoA were 0.04, 1.10, and 3.33 mM, respectively. The Vmax values with butyryl-CoA and acetoacetyl-CoA were comparable, but the Vmax/Km was higher for butyryl-CoA than for acetoacetyl-CoA. An apparent Km of 6.5 mM for phosphate was obtained with butyryl-CoA as the cosubstrate, whereas it was 12.9 mM with acetoacetyl-CoA as the cosubstrate. It remains to be established whether the putative compound acetoacetyl phosphate is produced in the PTB-catalyzed reaction with acetoacetyl-CoA.

Acetyl Coenzyme A↗

Purification and properties of 3-hydroxybutyryl-coenzyme A dehydrogenase from Clostridium beijerinckii ("Clostridium butylicum") NRRL B593.

The enzyme 3-hydroxybutyryl-coenzyme A (CoA) dehydrogenase has been purified 45-fold to apparent homogeneity from the solvent-producing anaerobe Clostridium beijerinckii NRRL B593. The identities of 34 of the N-terminal 35 amino acid residues have been determined. The enzyme exhibited a native M(r) of 213,000 and a subunit M(r) of 30,800. It is specific for the (S)-enantiomer of 3-hydroxybutyryl-CoA. Michaelis constants for NADH and acetoacetyl-CoA were 8.6 and 14 microM, respectively. The maximum velocity of the enzyme was 540 mumol min-1 mg-1 for the reduction of acetoacetyl-CoA with NADH. The enzyme could use either NAD(H) or NADP(H) as a cosubstrate; however, kcat/Km for the NADH-linked reaction was much higher than the apparent value for the NADPH-linked reaction. Also, NAD(H)-linked activity was less sensitive to changes in pH than NADP(H)-linked activity was. In the presence of 9.5 microM NADH, the enzyme was inhibited by acetoacetyl-CoA at concentrations as low as 20 microM, but the inhibition was relieved as the concentration of NADH was increased, suggesting a possible mechanism for modulating the energy efficiency during growth.

Amino Acid Sequence↗