Biodegradation of alkylpyridines by bacteria isolated from a polluted subsurface

Ten bacterial strains were isolated fromalkylpyridine polluted sediments 7.6 m below thesurface. These strains were able to degrade 11different alkylpyridine isomers. Degradation ratesdepended on number and position of the alkyl group. Isomers with an alkyl group at position 3 were moreresistant to microbial attack. Of the 10 strains, 6isolates were selected for detailed study. Theseisolates mineralized the isomers to CO₂,NH₄ ⁺, and biomass. All strains weregram-negative rods with a strict aerobic metabolism. Characterization of physiological and biochemicalproperties revealed similarity between strains. Eeachstrain however, had a limited substrate range whichenabled it to degrade no more than 2 to 3 compounds ofthe 14 alkylpyridine isomers tested. Examination ofthe genetic variability among cultures with therandomly amplified polymorphic DNA technique revealedhigh levels of genomic DNA polymorphism. The highestsimilarity between 2 strains (0.653) was observedbetween 2-picoline and 3-picoline degrading cultures. The molecular basis of the differences in substratespecificity is under investigation.     

Microbial degradation of n-alkyl tetrahydrothiophenes found in petroleum

Although n-alkyl-substituted tetrahydrothiophenes are found in nonbiodegraded petroleums, they are not found in petroleums which have undergone biodegradation in their reservoirs. These observations suggested that this group of compounds with alkyl chain lengths from approximately C10 to at least C30 is biodegradable. Two of these sulfides, 2-n-dodecyltetrahydrothiophene (DTHT) and 2-n-undecyltetrahydrothiophene, were synthesized, and their biodegradabilities were tested by using five gram-positive, n-alkane-degrading bacterial isolates. The alkyl side chains of these compounds were oxidized, and the major intermediates found in 2-n-undecyltetrahydrothiophene- and DTHT-metabolizing cultures were 2-tetrahydrothiophenecarboxylic acid (THTC) and 2-tetrahydrothiopheneacetic acid (THTA), respectively. Four n-alkane-degrading fungi were also shown to degrade DTHT, yielding both THTA and THTC. Quantitation of tetrahydrothiophene ring-containing products in 28-day-old bacterial and fungal cultures suggested that THTC and THTA were metabolized further to unidentified products. In addition, two of the bacterial isolates were shown to degrade a mixture of n-alkyl tetrahydrothiophenes isolated from Bellshill Lake crude oil.     

Microbial degradation of n-alkyl tetrahydrothiophenes found in petroleum.

Although n-alkyl-substituted tetrahydrothiophenes are found in nonbiodegraded petroleums, they are not found in petroleums which have undergone biodegradation in their reservoirs. These observations suggested that this group of compounds with alkyl chain lengths from approximately C10 to at least C30 is biodegradable. Two of these sulfides, 2-n-dodecyltetrahydrothiophene (DTHT) and 2-n-undecyltetrahydrothiophene, were synthesized, and their biodegradabilities were tested by using five gram-positive, n-alkane-degrading bacterial isolates. The alkyl side chains of these compounds were oxidized, and the major intermediates found in 2-n-undecyltetrahydrothiophene- and DTHT-metabolizing cultures were 2-tetrahydrothiophenecarboxylic acid (THTC) and 2-tetrahydrothiopheneacetic acid (THTA), respectively. Four n-alkane-degrading fungi were also shown to degrade DTHT, yielding both THTA and THTC. Quantitation of tetrahydrothiophene ring-containing products in 28-day-old bacterial and fungal cultures suggested that THTC and THTA were metabolized further to unidentified products. In addition, two of the bacterial isolates were shown to degrade a mixture of n-alkyl tetrahydrothiophenes isolated from Bellshill Lake crude oil.     

Biogenic amine-forming microbial communities in cheese

The aim of this study was to screen two cheese starter cultures and cheese-borne microbial communities with the potential to produce biogenic amines in cheese during ripening. Bacteria of the genera Enterococcus and Lactobacillus and coliform bacteria were isolated from Dutch-type semi-hard cheese at the beginning of the ripening period. Statistically significant counts of bacterial isolates were screened for the presence of specific DNA sequences coding for tyrosine decarboxylase (tyrDC) and histidine decarboxylase (hDC) enzymes. The PCR analysis of DNA from 14 Enterococcus and 3 Lactobacillus isolates confirmed the presence of the targetted DNA sequences. Simultaneously, 13 tyrDC- and 3 hDC-positive isolates were grown in decarboxylase screening medium and this was followed by HPLC analysis of the produced tyramine and histamine. Conventional and molecular taxonomic analyses of the above-mentioned isolates identified the following species: Enterococcus durans (7 strains), Enterococcus faecalis (3 strains), Enterococcus faecium (1 strain), Enterococcus casseliflavus (3 strains), Lactobacillus curvatus (1 strain), Lactobacillus lactis (1 strain) and Lactobacillus helveticus (1 strain). All of the above Enterococcus and two of the Lactobacillus strains originated from contaminating microbial communities. The L. helveticus strain, which was tyrosine decarboxylase-positive and exhibited tyramine production, originated from starter culture 1 used for cheese production. Comparison of partial tyrDC sequences of positive Enterococcus isolates revealed 89% sequence similarity, and that of hDC-positive Lactobacillus isolates revealed 99% sequence similarity.     

Isolation and characterization of diverse halobenzoate-degrading denitrifying bacteria from soils and sediments

Denitrifying bacteria capable of degrading halobenzoates were isolated from various geographical and ecological sites. The strains were isolated after initial enrichment on one of the monofluoro-, monochloro-, or monobromo-benzoate isomers with nitrate as an electron acceptor, yielding a total of 33 strains isolated from the different halobenzoate-utilizing enrichment cultures. Each isolate could grow on the selected halobenzoate with nitrate as the terminal electron acceptor. The isolates obtained on 2-fluorobenzoate could use 2-fluorobenzoate under both aerobic and denitrifying conditions, but did not degrade other halobenzoates. In contrast, the 4-fluorobenzoate isolates degraded 4-fluorobenzoate under denitrifying conditions only, but utilized 2-fluorobenzoate under both aerobic and denitrifying conditions. The strains isolated on either 3-chlorobenzoate or 3-bromobenzoate could use 3-chlorobenzoate, 3-bromobenzoate, and 2- and 4-fluorobenzoates under denitrifying conditions. The isolates were identified and classified on the basis of 16S rRNA gene sequence analysis and their cellular fatty acid profiles. They were placed in nine genera belonging to either the alpha-, beta-, or gamma-branch of the Proteobacteria, namely, Acidovorax, Azoarcus, Bradyrhizobium, Ochrobactrum, Paracoccus, Pseudomonas, Mesorhizobium, Ensifer, and Thauera. These results indicate that the ability to utilize different halobenzoates under denitrifying conditions is ubiquitously distributed in the Proteobacteria and that these bacteria are widely distributed in soils and sediments.     

一种银耳段木栽培杂菌的形态学鉴定与分子生物学分析

从四个不同银耳段木栽培场地采集杂菌样本,经初步鉴定后纯化得到48个菌株。通过对子实体、孢子及菌丝等的形态观察确认从银耳栽培段木上分离的48株杂菌隶属于炭团菌属,在形态上与截头炭团菌Annulohypoxylon annulatum最为相似。为了进一步确认从银耳栽培段木上分离的48株杂菌的分类地位,对其中14个供试菌株进行了ITS系统发育分析,结果表明:14个供试菌株之间的遗传距离为0.036时可以形成两个明显分枝,且分枝与地理来源之间并无明显相关性;供试菌株在分类地位上属于炭团菌属,与形态学鉴定结果一致,并与截头炭团菌的关系最为接近,遗传距离在0.2左右;与银耳伴生菌香灰菌的遗传距离为0.29左右。从75条引物中筛选出13条引物对所有48个供试菌株进行ISSR扩增,扩增共获得103条带,其中多态性条带72条,占条带总数的69.9%。聚类分析结果表明:在相似水平为75%时,48个菌株可以划分为5个类群,且类群的划分与地理来源之间并无明显相关性;多数供试菌株之间的遗传相似性较低,这表明供试菌株在DNA水平上存在比较显著的遗传变异,具有较丰富的遗传多样性。     

来自红海榄根际土壤的曲霉属真菌F7菌株及其生物活性分析

基于菌落和菌体的形态特征以及ITS序列分析结果,将分离自中国海南省海口市东寨港红树林保护区红海榄根际土壤的菌株F7鉴定为曲霉属黄绿组的一种真菌。在确定和优化菌株F7培养基的基础上,初步确定了适合其分泌活性代谢产物的改良查氏培养基组成:3%乳糖,1%蛋白胨,0.3%NaNO3,0.05%KCl,0.05%MgSO4·7H2O,0.001%FeSO4,0.1%K2HPO4,pH7.0。将菌株F7接种于该培养基中,28℃下160r/min振荡培养7d后收获发酵液,经乙酸乙酯和正丁醇萃取后获得了乙酸乙酯萃取物(EAE)、正丁醇萃取物(BE)以及水萃取物(WSE),其中EAE和BE对金黄色葡萄球菌、藤黄八叠球菌和枯草芽孢杆菌的生长显示出明显的抑制活性,最低抑菌浓度(MIC)介于0.625-5.0mg/mL之间。同时,上述3种萃取物对人肝癌细胞株HepG2的增殖也表现出一定的抑制活性,IC50约为120μg/mL左右。     

Genotypic and phenotypic polymorphism of environmental strains of the moderately thermophilic bacterium Sulfobacillus sibiricus

Five cultures of moderately thermophilic spore-forming acidophilic chemolithotrophic bacteria were isolated from the zones of spontaneous heating of pyrrhotine-containing pyrite-arsenopyrite gold-arsenic sulfide ores in an operating open pit (strains B1, B2, B3, OFO, and SSO). Analysis of the chromosomal DNA structure revealed differences between these cultures at the strain level (apart from B3 and SSO, which had identical restriction profiles). All the strains had a similar G + C DNA molar content (47.4-48.3%). The level of DNA reassociation was 85 to 95%. The similarity between the DNA of the type strain Sulfobacillus sibiricus N1 isolated from arsenopyrite ore concentrate and that of these strains (83-93%) indicates that they belong to the same species. The strains had similar values of pH and temperature optimal for growth on ferrous iron (1.6-2.0 and 45-55 degrees C, respectively). They were mixotrophs; Fe(II), S0, and sulfide minerals along with organic compounds were used as energy sources and electron donors. However, the kinetic parameters of growth and substrate oxidation varied from strain to strain. Genetic variety of the strains from diverse ecosystems and environments is possibly the result of the different rates of microevolution processes.     

Polyphasic characterization of poly-3-hydroxybutyrate-co-3-hydroxyvalerate (p(HB-co-HV)) metabolizing and denitrifying Acidovorax sp. strains

For the purpose of denitrification in small drinking water plants, a bacterial mixed population was isolated from a packed bed column bioreactor with poly-3-hydroxybutyrate-co-3-hydroxyvalerate (P(HB-co-HV)) as a substrate for the denitrification of ground water (10 degrees C). Isolates 2nIII from the mixed culture, with the ability to denitrify and metabolize P(HB-co-HV), were used as starter cultures for the elimination of nitrate in ground water. The strains were characterized by diverse techniques. Classical phenotypic studies lead to rRNA group III of the genus Pseudomonas. Results obtained by molecular techniques demonstrated that the 2nIII strains are members of the Comamonadaceae and shows similarities to the genus Acidovorax. However, an integration of the 2nIII isolates within one of the known Acidovorax species is not possible for the moment. The 2nIII starter cultures clustered close to Av. temperans according to their whole cell proteins and fatty acids, whereas in DNA/DNA hybridization no significant DNA binding (< 25%) was found. In contrast a significant but low degree of DNA/DNA hybridization was found between the 2nIII strains and Av. facilis and Av. delafieldii. Our polyphasic results lead to the conclusion that the 2nIII strains may constitute a separate Acicdovorax species.     

Biodegradation of the sulfonylurea herbicide chlorimuron-ethyl by the strain Pseudomonas sp. LW3

Eleven carbazole (CAR)-degrading bacterial strains were isolated from seawater collected off the coast of Japan using two different media. Seven isolates were shown to be most closely related to the genera Erythrobacter, Hyphomonas, Sphingosinicella, Caulobacter , and Lysobacter . Meanwhile, strains OC3, OC6S, OC9, and OC11S showed low similarity to known bacteria, the closest relative being Kordiimonas gwangyangensis GW14-5 (90% similarity). Southern hybridization analysis revealed that only five isolates carried car genes similar to those reported in Pseudomonas resinovorans CA10 ( car _CA10) or Sphingomonas sp. strain KA1 ( car _KA1). The isolates were subjected to GC-MS and the results indicated that these strains degrade CAR to anthranilic acid.     

Genotypic and phenotypic polymorphism of environmental strains of the moderately thermophilic bacterium <Emphasis Type="Italic">Sulfobacillus sibiricus</Emphasis>

Five cultures of moderately thermophilic spore-forming acidophilic chemolithotrophic bacteria were isolated from the zones of spontaneous heating of pyrrhotite-containing pyrite-arsenopyrite gold-arsenic sulfide ores in an operating open pit (strains B1, B2, B3, OFO, and SSO). Analysis of the chromosomal DNA structure revealed the differences between these cultures at the strain level (apart from B3 and SSO, which had identical restriction profiles). All the strains had a similar G+C DNA molar content (47.4–48.3%). The level of DNA reassociation was 85 to 95%. The similarity between the DNA of the type strain Sulfobacillus sibiricus N1 isolated from arsenopyrite ore concentrate and that of these strains (83–93%) indicates that they belong to the same species. The strains had similar values of pH and temperature optimal for growth on ferrous iron (1.6–2.0 and 45–55°C, respectively). They were mixotrophs; Fe(II), S^o, and sulfide minerals along with organic compounds were used as energy sources and electron donors. However, the kinetic parameters of growth and substrate oxidation varied from strain to strain. Genetic variety of the strains from diverse ecosystems and environments is possibly the result of the different rates of microevolution processes.     

Biological properties of some nitrogen-fixing associative enterobacteria

Enterobacteria isolates from potato tubers were able to fix nitrogen, to protect plants against phytopathogens and to produce phytohormones thus increasing the plant yield. These isolates were previously phenotypically identified as Erwinia carotovora; however, they differed from typical E. carotovora in a number of biological characteristics and were found to be nonphytopathogenic (avirulent) due to the lack of pectate lyase activity. A data matrix, containing 31 strains and 105 biological characteristics was used for computer cluster analysis. The avirulent strains formed a separate cluster more closely related to Klebsiella spp. strains (with a 0.67 level of similarity) than to typical phytopathogenic bacteria of the E. carotovora group (with a 0.48 level of similarity). A phylogenetic analysis based on restriction polymorphisms of an amplified ribosomal DNA spacer region revealed that the avirulent strains studied here were different from all Erwinia, Klebsiella and other enterobacteria species strains. The AP PCR/hybridization technique showed cross homology of amplified DNA of these avirulent strains and a lack of such homology with the DNA from strains of other species. Numerical taxonomy data, rDNA analysis and AP PCR/hybridization assays confirmed that these avirulent bacteria may be regarded as an independent group of enterobacteria.     

Degradation of Endrin, Aldrin, and DDT by Soil Microorganisms

Twenty microbial cultures which had been shown to degrade dieldrin were tested to determine their ability to degrade endrin, aldrin, DDT, gamma isomers of benzenehexachloride (gamma-BHC), and Baygon. All isolates were able to degrade DDT and endrin, whereas 13 degraded aldrin. However, none of them was able to degrade Baygon or gamma-BHC.     

Enrichment, isolation, and phylogenetic identification of polycyclic aromatic hydrocarbon-degrading bacteria from Elizabeth River sediments

The diversity of indigenous bacteria in sediments from several sites in the Elizabeth River (Virginia) able to degrade multiple polycyclic aromatic hydrocarbons (PAHs) was investigated by the use of classical selective enrichment and molecular analyses. Enrichment cultures containing naphthalene, phenanthrene, fluoranthene, or pyrene as a sole carbon and energy source were monitored by denaturing gradient gel electrophoresis (DGGE) to detect changes in the bacterial-community profile during enrichment and to determine whether the representative strains present were successfully cultured. The DGGE profiles of the final enrichments grown solely on naphthalene and pyrene showed no clear relationship with the site from which the inoculum was obtained. The enrichments grown solely on pyrene for two sample sites had >80% similarity, which suggests that common pyrene-degrading strains may be present in these sediments. The final enrichments grown on fluoranthene and phenanthrene remained diverse by site, suggesting that these strains may be influenced by environmental conditions. One hundred and one isolates were obtained, comprising representatives of the actinomycetes and alpha-, beta-, and gammaproteobacteria, including seven novel isolates with 16S rRNA gene sequences less than 98% similar to known strains. The ability to degrade multiple PAHs was demonstrated by mineralization of 14C-labeled substrate and growth in pure culture. This supports our hypothesis that a high diversity of bacterial strains with the ability to degrade multiple PAHs can be confirmed by the combined use of classical selective enrichment and molecular analyses. This large collection of diverse PAH-degrading strains provides a valuable resource for studies on mechanisms of PAH degradation and bioremediation.     

Regioselectivity of nitroglycerin denitration by flavoprotein nitroester reductases purified from two Pseudomonas species.

Two species of Pseudomonas capable of utilizing nitroglycerin (NG) as a sole nitrogen source were isolated from NG-contaminated soil and identified as Pseudomonas putida II-B and P. fluorescens I-C. While 9 of 13 laboratory bacterial strains that presumably had no previous exposure to NG could degrade low concentrations of NG (0.44 mM), the natural isolates tolerated concentrations of NG that were toxic to the lab strains (1.76 mM and higher). Whole-cell studies revealed that the two natural isolates produced different mixtures of the isomers of dinitroglycerol (DNG) and mononitroglycerol (MNG). A monomeric, flavin mononucleotide-containing NG reductase was purified from each natural isolate. These enzymes catalyzed the NADPH-dependent denitration of NG, yielding nitrite. Apparent kinetic constants were determined for both reductases. The P. putida enzyme had a Km for NG of 52 +/- 4 microM, a Km for NADPH of 28 +/- 2 microM, and a Vmax of 124 +/- 6 microM x min(-1), while the P. fluorescens enzyme had a Km for NG of 110 +/- 10 microM, a Km for NADPH of 5 +/- 1 microM, and a Vmax of 110 +/- 11 microM x min(-1). Anaerobic titration experiments confirmed the stoichiometry of NADPH consumption, changes in flavin oxidation state, and multiple steps of nitrite removal from NG. The products formed during time-dependent denitration reactions were consistent with a single enzyme being responsible for the in vivo product distributions. Simulation of the product formation kinetics by numerical integration showed that the P. putida enzyme produced an approximately 2-fold molar excess of 1,2-DNG relative to 1,3-DNG. This result could be fortuitous or could possibly be consistent with a random removal of the first nitro group from either the terminal (C-1 and C-3) positions or middle (C-2) position. However, during the denitration of 1,2-DNG, a 1.3-fold selectivity for the C-1 nitro group was determined. Comparable simulations of the product distributions from the P. fluorescens enzyme showed that NG was denitrated with a 4.6-fold selectivity for the C-2 position. Furthermore, a 2.4-fold selectivity for removal of the nitro group from the C-2 position of 1,2-DNG was also determined. The MNG isomers were not effectively denitrated by either purified enzyme, which suggests a reason why NG could not be used as a sole carbon source by the isolated organisms.     

Assessment of intra-species diversity among strains of Acinetobacter baumannii isolated from sites contaminated with petroleum hydrocarbons

A total of 96 crude oil-degrading bacterial strains were isolated from 5 geographically diverse sites in India that were contaminated with different types of petroleum hydrocarbons. The strains were identified by sequencing the genes that encode for 16S rRNA. Out of the 96 isolates, 25 strains were identified as Acinetobacter baumannii and selected for the study. All of the selected strains could degrade the total petroleum hydrocarbon fractions of crude oil. These 25 strains were biochemically profiled and grouped into 8 phenovars on the basis of multivariate analysis of their substrate utilization profiles. PCR-based DNA fingerprinting was performed using intergenic repetitive DNA sequences, which divided the selected 25 strains into 7 specific genomic clusters. tRNA intergenic spacer length polymorphism was performed to determine the intra-species relatedness among these 25 strains. It delineated the strains into 8 genomic groups. The present study detected specific variants among the A. baumannii strains with differential degradation capacities for different fractions of crude oil. This could play a significant role in in situ bioremediation. The study also revealed the impact of environmental factors that cause intra-species diversity within the selected strains of A. baumannii.     

Leishmania (Viannia): genetic analysis of cutaneous and mucosal strains isolated from the same patient

Ten pairs of Leishmania (Viannia) strains isolated from mucosal and cutaneous lesions of the same patient were analyzed genotypically in order to determine whether populations that had metastasized to mucosal sites differed from those in the cutaneous lesion. The strains were previously characterized by multi locus enzyme electrophoresis and/or monoclonal antibodies reactivity, and, for this study, only isolates from the same patient which were identified as the same species were employed. PCR-RFLP of internal transcribed spacer (ITS) rDNA, random amplified polymorphic DNA (RAPD), and schizodeme analyses were conducted. All genotyping methods revealed microheterogeneity between cutaneous and mucosal isolates from the same patient. The PCR-RFLP of the ITS rDNA and RAPD analysis were numerically analyzed through similarity coefficients and dendrograms were generated. All phenograms clustered cutaneous and mucosal strains of the same patient in one branch with a high degree of similarity, and phenetic analysis matched between them. Schizodeme analysis revealed differences between strains that composed some pairs. Genetic analyses indicate that some populations that metastasize to mucosal sites are distinguishable from the population in cutaneous lesions, however, other approaches will be required to associate genetic polymorphisms with the cutaneous or mucosal phenotype of strains.     

Diversity among Streptomyces Strains Causing Potato Scab

Eighty Streptomyces isolates, including 35 potato scab-inducing strains and 12 reference strains of Streptomyces scabies, were physiologically characterized by a total of 329 miniaturized tests. Overall similarities of all strains were determined by numerical taxonomy, with the unweighted average linkage (UPGMA) algorithm and simple matching (S(sm)) and Jaccard (S(j)) coefficients used as measures for similarity. Three cluster groups (A to C) were defined at a similarity level of 80.1% (S(sm)); these groups contained 14 clusters and 24 unclustered strains defined at a similarity level of 86.5% (S(sm)). Cluster group A contained strains phenotypically related to S. griseus or S. exfoliatus, whereas cluster group B contained strains which were phenotypically related to S. violaceus or S. rochei. The majority of the pathogenic isolates and reference strains were assigned to S. violaceus (57%) and S. griseus (22%). A DNA probe derived from the rRNA operon of S. coelicolor IMET 40271 was used to detect restriction fragment length polymorphisms (RELPs) among 40 pathogenic and nonpathogenic Streptomyces isolates. Southern blots revealed a high degree of diversity among the pathogenic strains tested. No significant correlation between numerical classification and RFLP grouping of Streptomyces strains could be revealed. The results obtained suggest that RFLP data are of minor importance in classification of Streptomyces species and that genes for pathogenicity determinants are spread among different Streptomyces species by mobilizable elements.     

Identification and isolation of anaerobic, syntrophic phthalate isomer-degrading microbes from methanogenic sludges treating wastewater from terephthalate manufacturing

The microbial populations responsible for anaerobic degradation of phthalate isomers were investigated by enrichment and isolation of those microbes from anaerobic sludge treating wastewater from the manufacturing of terephthalic acid. Primary enrichments were made with each of three phthalate isomers (ortho-, iso-, and terephthalate) as the sole energy source at 37 degrees C with two sources of anaerobic sludge (both had been used to treat wastewater containing high concentrations of phthalate isomers) as the inoculum. Six methanogenic enrichment cultures were obtained which not only degraded the isomer used for the enrichment but also had the potential to degrade part of other phthalate isomers as well as benzoate with concomitant production of methane, presumably involving strictly syntrophic substrate degradation. Our 16S rRNA gene-cloning analysis combined with fluorescence in situ hybridization revealed that the predominant bacteria in the enrichment cultures were affiliated with a recently recognized non-sulfate-reducing subcluster (subcluster Ih) in the group 'Desulfotomaculum lineage I' or a clone cluster (group TA) in the class delta-PROTEOBACTERIA: Several attempts were made to isolate these microbes, resulting in the isolation of a terephthalate-degrading bacterium, designated strain JT, in pure culture. A coculture of the strain with the hydrogenotrophic methanogen Methanospirillum hungatei converted terephthalate to acetate and methane within 3 months of incubation, whereas strain JT could not degrade terephthalate in pure culture. During the degradation of terephthalate, a small amount of benzoate was transiently accumulated as an intermediate, indicative of decarboxylation of terephthalate to benzoate as the initial step of the degradation. 16S rRNA gene sequence analysis revealed that the strain was a member of subcluster Ih of the group 'Desulfotomaculum lineage I', but it was only distantly related to other known species.     

Regioselective bioconversion of colchicine and thiocolchicine into their corresponding 3-demethyl derivatives

A variety of plant cell cultures and microbial soil isolates were screened for their ability to specifically demethylate colchicine at the C-3 position. Among all plant cell cultures tested, the newly established Colchicum variegatum culture was the only one able to demethylate colchicine, however unspecifically, yielding a mixture of 3-demethylcolchicine and 2-demethylcolchicine. In contrast, two bacterial strains were found among more than 500 isolates tested which expressed higgly regio-specific demethylation activity exclusively at C-3 of colchicine. The bioconversion product of the microorganisms, 3-demethylcolchicine, was completely excreted into the medium. The specific C-3 bioconversion of colchicine as well as of thiocolchicine by one of these strains, Bacillus IND-B 375, was characterized in function of substrate concentration and incubation time.