Regiospecific dechlorination of spiked tetra- and trichlorodibenzo-p-dioxins by anaerobic bacteria from PCDD/F-contaminated Spittelwasser sediments.

Samples were taken from sediment of the River Spittelwasser (district Bitterfeld, Germany), which is highly polluted with PCDD/Fs and other chloroorganic compounds. The sediment cores were separated into 10-20 cm thick layers, spiked with 50 microM of 1,2,3,4-tetrachlorodibenzo-p-dioxin and incubated for 8 months under anaerobic conditions in the presence of cosubstrates. Reductive dechlorination of the tetrachlorinated congener and formation of tri- and dichlorinated products were observed in all biologically active incubations. Analysis of subcultures spiked with 1,2,3- and 1,2,4-trichlorodibenzo-p-dioxin, respectively, revealed two different dechlorination pathways within the sediment cores. Pathway M was characterized by the simultaneous dechlorination of peri- and lateralchlorine atoms, whereas sequence SP was restricted to the dechlorination at positions flanked by chlorine atoms on both sides.

Analysis of a 2,4,6-trichlorophenol-dehalogenating enrichment culture and isolation of the dehalogenating member Desulfitobacterium frappieri strain TCP-A.

An anaerobic, 2,4,6-trichlorophenol ortho-dehalogenating mixed culture was enriched from sediment of the river Saale (Germany). Two isolated dechlorinating colonies (MK1 and MK2) consisted of rods of different lengths and thicknesses, indicating heterogeneity. Following subcultivation with thiosulfate as alternative electron acceptor and cocultivation with Clostridium celerecrescensT, the 2,4,6-trichlorophenol-dehalogenating bacterium Desulfitobacterium frappieri strain TCP-A was isolated and characterized regarding its taxonomic properties and the spectrum of chlorophenols that it dehalogenated. Four other bacterial strains were coenriched and identified as organisms with closest phylogenetic relatedness to the Clostridium type strains C. indolis, C. glycolicum, C. hydroxybenzoicum and C. sporosphaeroides (16S rDNA sequence identities of 99.5, 99.2, 94.4, and 93.5%, respectively). Amplified ribosomal DNA restriction analysis of the original dehalogenating cultures MK1 and MK2 (when not exposed to thiosulfate) confirmed the microbial heterogeneity and revealed the presence of two additional species related to the type strains of C. celerecrescens and Clostridium propionicum. Only one copy of the 16S rRNA genes of Desulfitobacterium frappieri in each of the clone libraries of MK1 and MK2 (containing 136 and 56 clones, respectively) was found by dot-blot hybridization, suggesting a relatively low number of the dehalogenating bacterium within the enrichment culture.

Defluvibacter lusatiae gen. nov., sp. nov., a new chlorohenol-degrading member of the alpha-2 subgroup of proteobacteria.

The two Gram-negative bacterial strains S1 and S4 were isolated from activated sludge of an industrial waste water treatment plant and exhibited a stable capability to degrade 2,4-dichlorophenol, 4-chloro-2-methylphenol, 4-chlorophenol and phenol. The cells were short rods with a polar flagellum, being mesophilic, strictly aerobic, oxidase-positive, and chemoorganotrophic. They utilized a range of amino acids, but only a restricted number of carbohydrates. Reassociation experiments with DNA from strains S1 and S4 revealed high interstrain similarity, indicating, that both strains belong to the same species. The phylogenetic position was determined by comparison of the almost complete 16S rDNA sequence of strain S1 with sequences of related bacteria. Strain S1 clustered with members of the alpha-2 subgroup of the Proteobacteria by forming a separate lineage within the radiation of Mesorhizobium, Phyllobacterium and Sinorhizobium. Both strains can be differentiated from members of related taxa by a set of physiological and chemotaxonomic properties including the ability to grow with norvaline, L-tryptophan, putrescine, glutarate and malonate, and by the presence of spermidine as major polyamine and of 12:0 3OH as fatty acid. Strain S1 is described as type strain of a new species and assigned to a new genus with the proposed name Defluvibacter lusatiae.

Purification and characterization of 2,4-dichlorophenol hydroxylase isolated from a bacterium of the alpha-2 subgroup of the Proteobacteria.

2,4-Dichlorophenol hydroxylase (EC 1.14.13.20) was purified to apparent homogeneity from the bacterial strain S1, a member of the alpha-2 subgroup of the Proteobacteria. The molecular masses of the native enzyme and the subunit were determined to be 256 and 64 kDa, respectively, suggesting a homotetrameric structure. The enzyme converted 2,4-dichlorophenol to 3,5-dichlorocatechol. The apparent K(m) values for 2,4-dichlorophenol, NADPH and NADH were 3, 240 and 420 microM, respectively. The enzyme hydroxylated a broad range of halogenated phenols. 3-Chloro-, 2,6-dichloro- and 2,4,6-trichlorophenol acted as 'non-substrate' effectors. The N-terminal sequence revealed 72% identity with the amino acid sequence deduced from the pJP4-encoded tfdB gene.

Degradation of 4-chloro-2-methylphenol by an activated sludge isolate and its taxonomic description.

The Gram-negative strain S1, isolated from activated sludge, metabolized 4-chloro-2-methylphenol by an inducible pathway via a modified ortho-cleavage route as indicated by a transiently secreted intermediate, identified as 2-methyl-4-carboxymethylenebut-2-en-4-olide by gas chromatography/mass spectrometry. Beside 4-chloro-2-methylphenol only 2,4-dichlorophenol and 4-chlorophenol were totally degraded, without an accumulation of intermediates. The chlorinated phenols tested induced activities of 2,4-dichlorophenol hydroxylase and catechol 1,2-dioxygenase type II. Phenol itself appeared to be degraded more efficiently via a separate, inducible ortho-cleavage pathway. The strain was characterized with respect to its physiological and chemotaxonomic properties. The fatty acid profile, the presence of spermidine as main polyamine, and of ubiquinone Q-10 allowed the allocation of the strain into the alpha-2 subclass of the Proteobacteria. Ochrobactrum anthropi was indicated by fatty acid analysis as the most similar organism, however, differences in a number of physiological features (e.g. absence of nitrate reduction) and pattern of soluble proteins distinguished strain S1 from this species.

Degradation of 3-aminophenol by Arthrobacter spec. mA3.

The bacterial strain mA3 capable of utilizing 3-aminophenol as the sole source of carbon, energy and nitrogen for growth was isolated from an enrichment culture and identified as an Arthrobacter species. Utilization of 0.68 mg/ml 3-aminophenol by batch cultures of this organism was characterized by a specific growth rate (mu) of 0.18 h-1 and a yield coefficient (Y) of 0.60. In chemostat cultures of strain mA3 we determined a critical dilution rate (Dc) of 0.175 h-1 by continuous addition of mineral salt medium with 0.5 mg/ml 3-aminophenol. Evidence was obtained that the degradation of catechol by 3-aminophenol induced as well as non-induced cells follows the beta-ketoadipate pathway. The excess ammonium ions, originating from 3-aminophenol degradation and not needed for assimilation were released into the medium. Cells adapted to 3-aminophenol exhibited a high substrate specificity. Among different aromatic substances tested, only catechol and 3,4-dihydroxybenzoate could serve as a carbon source for growth. The importance of the meta position of the amino group for the first step of hydroxylation is discussed in connection with the substrate specificity of whole mA3 cells.

Synthesis and antimicrobial activity of 7 alpha-methoxypyrimidinyl-ureidocephalosporins.

The synthesis of a series of 7 alpha-methoxy-7-[(R)-2-[3-[5-pyrimidinyl]ureido]-2-(4-hydroxyphenyl) acetamido]-3-cephem-4-carboxylates 2 is described. 7-[(R)-2-[3-[2-(p-Aminosulfonyl)-anilino-4-hydroxy-5-pyrimidinyl]ureido- 2-(4-hydroxyphenyl)acetamido]-7 alpha-methoxy-3-[(1-methyl-1H-tetrazol-5 -yl)thio]methyl-3-cephem-4-carboxylic acid, sodium salt (2k, UG-FA 132), has exhibited a broad range of antimicrobial activity. UG-FA 132 is highly active against Gram-positive and Gram-negative organisms, including Pseudomonas and lactamase producers, and shows potent activity against anaerobes. The high efficacy of UG-FA 132 was confirmed by in vivo experiments in mice.

Synthesis and antimicrobial activity of pyrimidinylureidocephalosporins.

The synthesis of a series of 7R-[(R)-2-[3-[5-pyrimidinyl]ureido]-2-(aryl)acetamido]-3-cephem-4- carboxylates is described. Variation of the substituents at the 3-position in the cephem nucleus, at the 2-position of the pyrimidine ring, and of the phenyl residue in the acyl side chain is carried out. Qualitative structure-activity relationships in this series are discussed. VX-VD 2, the most interesting compound, exhibits broad antimicrobial activity against Gram-negative bacteria, including Pseudomonas aeruginosa.

[6R-[(R)-2-[3-[2-(p-Aminosulfonyl)anilino-4-hydroxy-5- pyrimidinyl]ureido]-2-(4-hydroxyphenyl)acetamido]-penicillanic acid, sodium salt (VX-VC 43), a new broad-spectrum beta-lactam antibiotic. In vitro and in vivo antibiotic activity]. / 6R-[(R)-2-[3-[2-(p-Aminosulfonyl)anilino-4-hydroxy-5-pyrimidinyl] ureido]-2-(4-hydroxyphenyl)acetamido]-penicillansäure, Natriumsalz (VX-VC 43), ein neues Breitspektrum-beta-Lactam-Antibiotikum. Antibiotische Aktivität in vitro und in vivo.

6R-[(R)-2-[3-[2-(p-Aminosulfonyl) anilino-4-hydroxy-5-pyrimidinyl] ureido]-2-(4-hydroxyphenyl)acetamido]-penicillanic acid, sodium salt (VX-VC 43), a pyrimidinylureidopenicillin, is a broad-spectrum antibiotic. In vitro it is more active than piperacillin, apalcillin and mezlocillin especially against the following strains; E. coli, Ps. aeruginosa, Ps. stutzeri, K. pneumoniae, Eb. cloacae, Ser. marcescens, Proteus, Sh. flexneri, Y. enterocolitica, Cb. freundii, Acb. calcoaceticus, Bacteroides and Sc. faecalis. The minimal inhibitory concentration (MIC, micrograms/ml), for VX-VC 43 lies between 0.06 and 4 for piperacillin between 0.25 and 16, for apalcillin between 0.25 and 8, and for mezlocillin between 0.5 and 32. The action of VX-VC 43 is bactericidal. In tests against patient-isolates of E. coli (n = 50), Ps. aeruginosa (n = 50), K. pneumoniae (n = 46) and Eb. cloacae (n = 50) VX-VC 43 is clearly more active than Piperacillin. In the case of Ps. aeruginosa 2 micrograms/ml VX-VC 43 inhibits 43.9% of the bacteria and 8.5% with piperacillin; for E. coli 0.25 micrograms/ml inhibits 43.9% with VX-VC 43 and 0% with piperacillin; for K. pneumoniae 4 micrograms/ml inhibits 43.7% with VX-VC 43 and 28% for piperacillin; with Eb. cloacae 2 micrograms/ml inhibits 78% with VX-VC 43 and 4% with piperacillin. Addition of 50% human serum, or a change in culture medium pH (from 6 to 8) has little or no effect on the MIC of VX-VC 43 or piperacillin.(ABSTRACT TRUNCATED AT 250 WORDS)

Synthesis and antibacterial activity of pyrimidinylureidopenicillins.

The 6R-[(R)-2-[3-[5-pyrimidinyl]ureido]-2-(4-hydroxyphenyl) acetamido]-penicillanic acids (10), prepared by two synthetic routes, exhibit broad antimicrobial activity against Gram-positive and Gram-negative bacteria. Their structure activity relationships are discussed. 6R-[(R)-2-[3-[2-(p-Aminosulfonyl)anilino-4-hydroxy-5-pyrimidinyl] ureido]-2-(4-hydroxyphenyl)acetamido]-penicillanic acid, sodium salt (VX-VC 43, 10m), the most active compound, shows very low MIC (minimal inhibitory concentration) values against clinically important Gram-negative bacteria, primarily Pseudomonas aeruginosa.

[Microbial side chain splitting of phenylurea and carbonic acid anilides]. / Mikrobielle Seitenkettenabspaltung von Phenylharnstoffen und Carbonsäureaniliden.

A Gram- negative rod-shaped bacterium 28/1 isolated by enrichment cultures is able to hydrolyze the amide bond of some phenylurea herbicides and acid anilide herbicides by an inducible amidase. 7.5% of 0.3 mumol.ml-1 linuron (3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea) are hydrolyzed after 16 hours. 1,1-Dimethylphenylureas are not degraded. Acid anilides are hydrolyzed at a higher rate, 80% of 0.5 mumol.ml-1 N-(4-chlorophenyl)-propionamide and N-(4-nitrophenyl)-propionamide are transformed after 6 hours. The 1-methoxy-1-methyl phenylureas are effective inducers. Linuron-induced cells have a specific activity of 3-4 nmol per mg dry weight per min on the substrate N-(3,4-dichlorophenyl)-propionamide (Propanil). The rate of hydrolysis is influenced by substituents of the aniline ring and by the structure of the side chain of the acid anilides.

Derivatives of 4-dihydro-4-deoxy-4(R)-amino spectinomycin and their activity against susceptible and resistant Escherichia coli strains.

A number of alkyl and acyl derivatives of 4-dihydro-4-deoxy-4(R)-amino spectinomycin were tested against various Escherichia coli strains, possessing different susceptibilities to spectinomycin. The influence of the lipophilicity and the length of the side chain substituents of the derivatives was compared to both minimal inhibitory concentration values and stability to adenyltransferase. Derivatives with a chain length of more than 10 carbon atoms demonstrated a significantly higher activity against all investigated strains, whether susceptible or resistant. The same inhibitory effect was achieved with short-chain aminoacyl derivatives only against susceptible strains. Other short-chain derivatives possessed no advantage to spectinomycin. A 10-fold decrease in the affinity for adenyltransferase was achieved in compounds with a high lipophilicity (log P), i.e., in aliphatic substituted derivatives with a log P greater than 4 and in benzoyl-substituted derivatives with a log P greater than 2. Derivatives with branched alkyl chains and long side chains displayed a different mode of action than spectinomycin. They possessed strong activity against strains with an altered ribosomal binding site and a decreased influence of pH on antimicrobial activity.

Modification of spectinomycin. 2. Derivatives of 4-dihydro-4-deoxy-4(R)-aminospectinomycin.

Acyl derivatives 5a approximately j and alkyl derivatives 7a approximately r of 4-dihydro-4-deoxy-4(R)-aminospectinomycin (1a) were prepared and tested for antibacterial activity. Only acyl compounds derived from long chain aliphatic acids showed activity in vitro, but were inactive when tested in vivo. All alkyl derivatives were active in vitro. In vivo however only the short chain derivatives 7a approximately c were active. Compound 7b showed higher activity than spectinomycin.