NAD+-Dependent (S)-Specific Secondary Alcohol Dehydrogenase Involved in Stereoinversion of 3-Pentyn-2-ol Catalyzed by Nocardia fusca AKU 2123

An NAD⁺-dependent alcohol dehydrogenase was purified to homogeneity from Nocardia fusca AKU 2123. The enzyme catalyzed (S)-specific oxidation of 3-pentyn-2-ol (PYOH), i.e., part of the stereoinversion reaction for the production of (R)-PYOH, which is a valuable chiral building block for pharmaceuticals, from the racemate. The enzyme used a broad variety of secondary alcohols including alkyl alcohols, alkenyl alcohols, acetylenic alcohols, and aromatic alcohols as substrates. The oxidation was (S)-isomer specific in every case. The K _m and V _max for (S)-PYOH and (S)-2-hexanol oxidation were 1.6 mM and 53 μmol/min/mg, and 0.33 mM and 130 μmol/min/mg, respectively. The enzyme also catalyzed stereoselective reduction of carbonyl compounds. (S)-2-Hexanol and ethyl (R)-4-chloro-3-hydroxybutanoate in high optical purity were produced from 2-hexanone and ethyl 4-chloro-3-oxobutanoate by the purified enzyme, respectively. The K _m and V _max for 2-hexanone reduction were 2.5 mM and 260 μmol/min/mg. The enzyme has a relative molecular mass of 150,000 and consists of four identical subunits. The NH₂-terminal amino acid sequence of the enzyme shows similarity with those of the carbonyl reductase from Rhodococcus erythropolis and phenylacetaldehyde reductase from Corynebacterium sp.     

Production of (R)-3-pentyn-2-ol through stereoinversion of racemic 3-pentyn-2-ol by Nocardia fusca AKU 2123

Wet cells of Nocardia fusca AKU 2123 are good catalysts for the production of (R)-3-pentyn-2-ol (PYOH) from (RS)-PYOH through a stereoinversion reaction. Under optimal conditions (350 mM potassium phosphate buffer, pH 8.0, 30% (w/v) wet cells, 0.12% NADPH, 10% glucose, and 30 U/ml glucose dehydrogenase) (R)-PYOH of high optical purity (98.7% e.e.) was produced from 2% (v/v) (RS)-PYOH with a yield of 70.4% by 140 h incubation. Received: 22 January 1999 / Received revision: 23 April 1999 / Accepted: 1 May 1999     

(S)-3-Pentyn-2-ol production through microbial enzyme-catalyzed, highly enantioselective hydrolysis of racemic 3-pentyn-2-ol esters

Air-dried cells of Hansenula nonfermentans AKU 4332 catalyzed the production of (S)-3-pentyn-2-ol from (RS)-3- pentyn-2-ol acetate ester at 10% (v/v). The product was formed at 96.6% e.e. with a molar yield of 45% in 24 h. © Rapid Science Ltd. 1998     

Production of (R )-3-pentyn-2-ol through stereospecific hydrolysis of racemic 3-pentyn-2-ol esters with microbial enzymes

Microorganisms and commercial enzymes were screened for their ability to produce (R)-3-pentyn-2-ol from racemic 3-pentyn-2-ol esters through stereospecific hydrolysis. Among the esters formed with acetic acid, propionic acid, hexanoic acid and benzoic acid, the acetate was most effectively hydrolyzed by microbial cells and commercial lipases with high stereospecificity. Rhodococcus rubropertinctus AKU NOC082 was a good catalyst for (R)-3-pentyn-2-ol production through the hydrolytic resolution of racemic 3-pentyn-2-yl acetate. With 15%, 25% and 50% (v/v) racemic 3-pentyn-2-yl acetate as the substrate, 42.6%, 40.8% and 40.0% was hydrolyzed in 5 h, 10 h and 98 h respectively, under the optimized conditions (pH 7.0, 30 °C, 7.5% wet cell concentration), the (R) enantiomer of 3-pentyn-2-ol being formed with an optical purity of 97.8%, 98.0% and 94.2% respectively. Received: 2 June 1998 / Received revision: 3 August 1998 / Accepted: 3 September 1998     

NAD(+)-dependent (S)-specific secondary alcohol dehydrogenase involved in stereoinversion of 3-pentyn-2-ol catalyzed by Nocardia fusca AKU 2123

An NAD(+)-dependent alcohol dehydrogenase was purified to homogeneity from Nocardia fusca AKU 2123. The enzyme catalyzed (S)-specific oxidation of 3-pentyn-2-ol (PYOH), i.e., part of the stereoinversion reaction for the production of (R)-PYOH, which is a valuable chiral building block for pharmaceuticals, from the racemate. The enzyme used a broad variety of secondary alcohols including alkyl alcohols, alkenyl alcohols, acetylenic alcohols, and aromatic alcohols as substrates. The oxidation was (S)-isomer specific in every case. The K(m) and Vmax for (S)-PYOH and (S)-2-hexanol oxidation were 1.6 mM and 53 mumol/min/mg, and 0.33 mM and 130 mumol/min/mg, respectively. The enzyme also catalyzed stereoselective reduction of carbonyl compounds. (S)-2-Hexanol and ethyl (R)-4-chloro-3-hydroxybutanoate in high optical purity were produced from 2-hexanone and ethyl 4-chloro-3-oxobutanoate by the purified enzyme, respectively. The K(m) and Vmax for 2-hexanone reduction were 2.5 mM and 260 mumol/min/mg. The enzyme has a relative molecular mass of 150,000 and consists of four identical subunits. The NH2-terminal amino acid sequence of the enzyme shows similarity with those of the carbonyl reductase from Rhodococcus erythropolis and phenylacetaldehyde reductase from Corynebacterium sp.     

Mouse pathogenicity studies of Nocardia asteroides complex species and clinical correlation with human isolates

Abstract Nocardia asteroides complex organisms derived from human specimens between 1979 and 1992 were identified on the species level. Of 117 N. asteroides complex organisms, 34 (29%) were N. farcinica , 28 (24%) were N. nova , and 55 (47%) were N. asteroides sensu stricto . An analysis of the specimen sites from which the organisms were derived showed that isolates derived from blood, brain, or bone marrow were more likely to be N. farcinica than the other two species. A study of the virulence of ten strains of each species was undertaken, using a mouse model with intravenous inoculation. The 50% lethal doses (LD₅₀) for N. farcinica were significantly lower than those of the other two species. LD₅₀ values for N. nova and N. asteroides were not significantly different. The above data confirming the greater virulence of N. farcinica support the identification of species within the N. asteroides complex.     

Thiostrepton induced proteins in Streptomyces, Amycolatopsis and Nocardia species

Abstract Thiostrepton-induced proteins have been observed in several actinomycetes, including Streptomyces clavuligerus (15 kDa protein), S. griseus (21 kDa), Nocardia lactamdurans (17 kDa), Amycolatopsis sp 239 (14 and 16 kDa), S. fradie (18 and 20 kDa) and S. coelicolor (17, 19, 30 and 56 kDa). The thiostrepton-induced proteins of S. coelicolor seem to be identical to those reported in S. lividans . The induction of the 18 and 20 kDa proteins of S. fradiae (up to 20% of the total protein in the cells) was dependent upon the concentration of thiostrepton (1 to 50 μg per ml) added to the cultures. The induction of proteins by thiostrepton in N. lactamdurans (and probably in the other actinomycetes as well) is not mediated by the tsr gene of pIJ702, since spontaneous thiostrepton-resistant mutants of N. lactamdurans which do not carry the tsr gene were used for the induction studies. Induction of proteins by thiostrepton may be a protective mechanism to counteract the strong effect of this antibiotic which is known to be produced by several soil microorganisms.     

Insights from the comparative genome analysis of natural rubber degrading Nocardia species

Nocardia are known to be a facultative human pathogen and can cause infection in immune compromised patients. Though the details research on the virulence factors of Nocardia are scanty but numerous genes that code such factors were reported from different species of Nocardia. Despite of the presence of several virulence factors, species of this genus have been shown to have role in remediation of many toxic and hazardous materials from the environment. In this study, genome sequences of rubber degrading Nocardia sp. BSTN01 and N.nova SH22a have been analyzed to locate the potential virulence genes. Also, the genomes of facultative pathogenic Nocardia like, N.africana, N. brasiliensis, N. kruczakiae, N. transvalensis and N. veterana have been analyzed to find the gene encoding latex clearing protein (Lcp), a rubber oxygenase enzyme of Gram-positive action bacteria. The study provides an insight about the potentiality of rubberdegrading Nocardia species to emerge as future human pathogens and also the probability of a serious concern if the studied facultative pathogens of Nocardia like N. africana, N. brasiliensis, N. kruczakiae, N. transvalensis and N. veterana are capable of degrading rubber, a regularly used material in clinics. Moreover, use of such possible pathogenic strains for their known role in bioremediation of rubber waste from the environment might be deleterious.     

Nocardia ninae sp.nov.致放线菌性足菌肿1例

报道1例Nocardia ninae致放线菌性足菌肿。女性,37岁,上胸部红斑、丘脓疱疹、结节、窦道、斑块20余年。初起于右锁骨中部,逐渐累及前胸部及颈下段,偶有轻微疼痛感。检查:颈下部、上胸部有大片红斑块,其上有散在分布的丘脓疱疹、结节、窦道和结痂,之间有条索状隆起。病理检查:见硫磺颗粒。实验室培养:两种菌生长。经16S rRNA基因全序列测序分析,两株菌分别鉴定为:表皮葡萄球菌及与Nocardia ninae OFN 02.72T系统进化关系较近,相似性为98.1%的诺卡菌。诊断:Nocardia ninae致放线菌性足菌肿。     

诺卡氏菌对油酸的羟基化作用

诺卡氏菌(Nocardia sp．N13)休止细胞对油酸(顾-9-十八碳烯酸)进行羟基化作用。用休止细胞转化时最适温度为30℃,最适pH为6．5,当菌体(干菌)与底物的最适比例为20 ：1对,对油酸的转化率为83．4％,不同的表面活性剂影响转化的效果。N13休止细胞在磷酸缓冲液中重复转化3次仍可保持50％左右的转化率。红外光谱、质谱、棱磁共振鉴定产物为10－羟基硬脂酸。     

Propterol B,a further 1,3-diarylpropan-2-ol from Pterocarpus marsupium

The structure of propterol B, a heartwood extract of Pterocarpus marsupium, has been established as the hitherto unreported 1-(2,4-dihydroxyphenyl)-3-(4-hydroxyphenyl)propan-2-ol. The trimethyl ether of propterol B on oxidation with Jones reagent gave 1-(2,4-dimethoxyphenyl)-3-(4-methoxyphenyl)propan-2-one.     

Evaluation of the enantiomers of 1-octen-3-ol and 1-octyn-3-ol as attractants for mosquitoes associated with a freshwater swamp in Florida, U.S.A

Field studies were conducted at wooded wetlands in Gainesville, FL, U.S.A., to assess responses of natural populations of adult mosquitoes (Diptera: Culicidae) to American Biophysics MM-X and Coleman MD-2500 traps baited with enantiomers of 1-octen-3-ol, a naturally occurring compound, and 1-octyn-3-ol, a closely related synthetic compound. Overall, the same species of mosquitoes were attracted by all enantiomers, although the (R)-(+) isomer of octenol generally attracted more species, and it is the isomer produced in greatest proportion in nature. Traps baited with the R-enantiomer caught greater numbers of mosquitoes than those baited with the S-enantiomer of each compound, whereas traps baited with S-enantiomers were equally or slightly less attractive than those baited with carbon dioxide only.     

Production of bioactive metabolites by Nocardia levis MK-VL_113

Aims: To isolate and identify the bioactive compounds produced by Nocardia levis MK‐VL_113. Methods and Results: Cultural characteristics of Noc. levis isolated from laterite soils of Guntur region were recorded on International Streptomyces Project media. Morphological studies of the strain through scanning electron microscopy revealed the clear pattern of its hyphal fragmentation into rod‐shaped bacilli. Chemical examination of the secondary metabolites of the strain grown on sucrose–tryptone broth led to the isolation of three fractions active against Bacillus cereus. Further analysis of second fraction resulted in the isolation of two active subfractions. Two different phthalate esters, namely, bis‐(2‐ethylhexyl) phthalate and bis‐(5‐ethylheptyl) phthalate, were purified from the first active subfraction, and the structural elucidation of these compounds was confirmed on the basis of FT‐IR, mass and NMR spectroscopy. The partially purified second subfraction subjected to Gas Chromatography–Mass spectroscopy contained nine components: decanedioic acid; 2,6‐piperdione monooxime; 1‐eicosanol; beta‐1‐arabinopyranoside, methyl; cyclopentaneundecanoic acid; hexadecanoic acid; silane, trichloro eicosyl; 1‐hexacosanol; and 1,2‐dodecanediol. The antimicrobial activity of the bioactive compounds produced by Noc. levis was expressed in terms of minimum inhibitory concentration. Conclusions: The present study clearly revealed that the metabolites of Noc. levis act as bioactive compounds against Gram‐positive and Gram‐negative bacteria, yeast and filamentous fungi. It also supports the idea that there are a number of rare actinomycetes remained to be explored for new bioactive compounds. Significance and Impact of the Study: Metabolites of Noc. levis exhibited antibacterial and antifungal activities. This is the first report of bis‐(5‐ethylheptyl) phthalate as well as the nine partially purified compounds from actinomycetes. In addition, this is also the first report of bis‐(2‐ethylhexyl) phthalate from the genus Nocardia.     

Propterol: A 1,3-diarylpropan-2-ol from Pterocarpus marsupium

The structure of propterol, an extractive of the heartwood of Pterocarpus marsupium, has been established to be 1,3-bis (4-hydroxyphenyl)propan-2-ol, on the basis of its spectral data and Jones oxidation of its dimethyl ether to known 1,3-bis(4-methoxyphenyl)propan-2-one. Propterol appears to be among the simplest of highly reduced flavonoids encountered in nature.     

Metabolism of daidzein by Nocardia species NRRL 5646 and Mortierella isabellina ATCC 38063

The phytoestrogen daidzein was metabolized by Nocardia species NRRL 5646 to give two metabolites obtained by hydroxylation and methylation. These metabolites were spectrally characterized as 7-methoxy-4'-hydroxyisoflavone (isoformononetin) and 7,8-dimethoxy-4'-hydroxyisoflavone. Mortierella isabellina ATCC 38063 was able to metabolize daidzein to the unusual metabolite daidzein-4'-rhamnopyranoside.     

Genome based analysis of type-I polyketide synthase and nonribosomal peptide synthetase gene clusters in seven strains of five representative Nocardia species

Background

Actinobacteria of the genus Nocardia usually live in soil or water and play saprophytic roles, but they also opportunistically infect the respiratory system, skin, and other organs of humans and animals. Primarily because of the clinical importance of the strains, some Nocardia genomes have been sequenced, and genome sequences have accumulated. Genome sizes of Nocardia strains are similar to those of Streptomyces strains, the producers of most antibiotics. In the present work, we compared secondary metabolite biosynthesis gene clusters of type-I polyketide synthase (PKS-I) and nonribosomal peptide synthetase (NRPS) among genomes of representative Nocardia species/strains based on domain organization and amino acid sequence homology.

Results

Draft genome sequences of Nocardia asteroides NBRC 15531^T, Nocardia otitidiscaviarum IFM 11049, Nocardia brasiliensis NBRC 14402^T, and N. brasiliensis IFM 10847 were read and compared with published complete genome sequences of Nocardia farcinica IFM 10152, Nocardia cyriacigeorgica GUH-2, and N. brasiliensis HUJEG-1. Genome sizes are as follows: N. farcinica, 6.0 Mb; N. cyriacigeorgica, 6.2 Mb; N. asteroides, 7.0 Mb; N. otitidiscaviarum, 7.8 Mb; and N. brasiliensis, 8.9 - 9.4 Mb. Predicted numbers of PKS-I, NRPS, and PKS-I/NRPS hybrid clusters ranged between 4–11, 7–13, and 1–6, respectively, depending on strains, and tended to increase with increasing genome size. Domain and module structures of representative or unique clusters are discussed in the text.

Conclusion

We conclude the following: 1) genomes of Nocardia strains carry as many PKS-I and NRPS gene clusters as those of Streptomyces strains, 2) the number of PKS-I and NRPS gene clusters in Nocardia strains varies substantially depending on species, and N. brasiliensis strains carry the largest numbers of clusters among the species studied, 3) the seven Nocardia strains studied in the present work have seven common PKS-I and/or NRPS clusters, some of whose products are yet to be studied, and 4) different N. brasiliensis strains have some different gene clusters of PKS-I/NRPS, although the rest of the clusters are common within the N. brasiliensis strains. Genome sequencing suggested that Nocardia strains are highly promising resources in the search of novel secondary metabolites.

Electronic supplementary material

The online version of this article (doi: 10.1186/1471-2164-15-323) contains supplementary material, which is available to authorized users.     

Production of L-tartaric acid by immobilized bacterial cells Nocardia tartaricans

Nocardia tartaricans converted sodium cis-epoxysuccinate to L-tartrate. The highest cis-epoxysuccinate hydrolase activity (37.7 U mg^–1) was obtained with 0.02% (w/v) sodium deoxycholate, but this inactivated the cells. Immobilized N. tartaricans in pectate gel showed higher enzyme activity (51 U mg ^–1) compare to the free cells (8.9 U mg ^–1). After 450 days, the immobilized cells still possessed 0.65 U mg ^–1, i.e. 30% of the initial enzyme activity.     

放线菌与诺卡菌所致感染性皮肤肉芽肿的鉴别诊断及治疗

感染性肉芽肿是一类慢性增生性炎症。放线菌和诺卡菌所致感染性肉芽肿实属少见,但两者临床症状、体征相似,易误诊或漏诊。本文报道1例放线菌与1例诺卡菌所致皮肤感染性肉芽肿,通过皮肤组织病理学检查、细菌培养、生化鉴定及细菌分子生物学检测,最终明确诊断。进一步分析2种感染的病因学、流行病学、临床表现、诊断和鉴别诊断及治疗,并结合最新研究进展,可帮助临床医师更好地认识放线菌属细菌所致感染性皮肤肉芽肿,以便于及时诊断、及时治疗。这2种感染有很多相似之处,也有各自特点,需临床医师求同存异,仔细鉴别;还需与其他感染性肉芽肿如皮肤结核、孢子丝菌病或着色芽生菌病等鉴别诊断。     

Characterization of Nocardia plasmid pXT107

Nocardia,Rhodococcus and Streptomyces,all members of the actinomycetes family,areGram-positive eubacteria with high G C content and able to form mycelium.We report here a newlyidentified plasmid pXT107 of Nocardia sp.107,one of the smallest circular plasmids found in Nocardia.The complete nucleotide sequence of pXT107 consisted of 4335 bp with 65% G C content,and encodedone replication extragenic palindromic (Rep) and six hypothetical proteins.The Rep,double-strand originand single-strand origin of pXT 107 resembled those of typical rolling-circle-replication plasmids,such aspNI100 of Nocardia,pRE8424 of Rhodococcus and pIJ101 of Streptomyces.The Escherichia coli-Nocardiashuttle plasmid pHAQ22,containing the rep gene of pXT107,is able to propagate in Nocardia but not inStreptomyces.