A novel Streptoverticillium cinnamonium var scleroticum producing a polyene antibiotic

A novel Streptoverticillium sp. G-55 was isolated from a soil sample (collected from Panjim, Goa) which produces sclerotia under specific environmental conditions, both in liquid and solid media. It was further identified by taxonomic studies as Streptoverticillium cinnamoneum var scleroticum. The species produces a pentaene polyene macrolide antibiotic (HA-94) under submerged culture conditions which shows promising antifungal and antibacterial activity in vitro.     

Production of a Naphthoquinone Pigment by a Species of Streptoverticillium and Its Accumulation by a Streptomycete

A naphthoquinone pigment produced by a species of Streptoverticillium was accumulated by a Streptomyces sp. when the two organisms were grown in mixed cultures.     

Auxotrophic mutants of the producer of the antibiotic mycoheptin Streptoverticillium mycoheptinicum

The lethal and mutagenic effects of N-nitrozo-N-methyl biuret (NMB), N-nitrozo-N-methyl urea (NMU) and UV light on Streptoverticillium mycoheptinicum, strains O883 and 852, were studied. The concentrations of NMB were 0.005, 0.1 and 0.25 per cent, the exposure time was 2, 4 and 6 hours. The concentration of NMU was 1 per cent and the exposure time was 1, 2, 3, 4 and 5 hours. The dose of UV light was 2000 erg/mm2. When the spores of Streptoverticillium mycoheptinicum, strain O883, were treated with NMB, the frequency of auxotrophic mutants increased from 0.63 to 3.4 per cent with an increase of the mutagen concentration from 0.05 to 0.25 per cent and the exposure time from 2 to 6 hours. More than 80 auxotrophic mutants were selected. When Streptoverticillium mycoheptinicum, strain 852, was treated with NMU, the frequency of auxotrophic mutants ranged from 0.5 to 2.4 per cent. Fifty-seven auxotrophic mutants were selected. The majority of the auxotrophic mutants selected with the use of NMB and NMU was unstable. Exposure of Streptoverticillium mycoheptinicum, strains 852, 10/69 Met and 54/100 Lys to UV light resulted in formation of groups of polyauxotrophic mutants.     

Classification of acidophilic, neutrotolerant and neutrophilic streptomycetes by nucleotide sequencing of 5S ribosomal RNA.

Complete 5S ribosomal RNA sequences were obtained for four acidophilic actinomycetes, seven neutrophilic streptomycetes and a strain of Streptoverticillium baldaccii. All of the organisms contained RNAs belonging to the 120 nucleotide type. An evolutionary tree was generated after combining the test data with results from similar studies on representative Gram-positive bacteria. The acidophilic, neutrotolerant and neutrophilic actinomycetes were recovered in a distinct cluster that was equated with the genus Streptomyces. The sequence data support the view that the genera Chainia, Elytrosporangium, Kitasatoa and Microellobosporia should be considered as synonyms of the genus Streptomyces. The recovery of the Streptoverticillium baldaccii strain on the fringe of the Streptomyces cluster is also consistent with current trends in the taxonomy of these organisms. Further work is needed to determine the taxonomic status of the two streptomycete subgroups that comprised the streptomycete cluster.     

Bacterial colony screening with a Streptomyces DNA probe

Restriction fragments of 1.5 kb-3.5 kb length were selected from a SalI digest of Streptomyces coriofaciens ISP5485 DNA. After radiolabelling, these fragments were used as a molecular probe. A number of actinomycetes was screened in colony hybridization. Streptomyces and Streptoverticillium strains were recognized by the probe and the hybridization sensitivity was high with isolated DNA.     

Prodiginine (Prodigiosin-Like) Pigments from Streptoverticillium rubrireticuli, an Organism That Causes Pink Staining of Polyvinyl Chloride

Red pigments were extracted from Streptoverticillium rubrireticuli strain 100-19, an organism frequently incriminated in pink staining of polyvinyl chloride. These pigments were identified as undecylprodiginine and butylcycloheptylprodiginine.     

Streptomyces subtilisin inhibitor-like proteins are distributed widely in streptomycetes.

Streptomyces subtilisin inhibitor-like proteins were found to be distributed widely in streptomycetes by using the combination of the convenient, newly developed plate assay system and an established liquid culture assay. Almost all the strains formerly categorized as Streptoverticillium species produced proteins that exhibited inhibitory activity against both subtilisin BPN' and trypsin. N-terminal regions of three purified proteins showed high structural similarity to those of other previously reported SIL inhibitors.     

Production of native-type Streptoverticillium mobaraense transglutaminase in Corynebacterium glutamicum

We previously observed secretion of active-form transglutaminase in Corynebacterium glutamicum by coexpressing the subtilisin-like protease SAM-P45 from Streptomyces albogriseolus to process the prodomain. However, the N-terminal amino acid sequence of the transglutaminase differed from that of the native Streptoverticillium mobaraense enzyme. In the present work we have used site-directed mutagenesis to generate an optimal SAM-P45 cleavage site in the C-terminal region of the prodomain. As a result, native-type transglutaminase was secreted.     

Phospholipase D production using immobilized cells of Streptoverticillium cinnamoneum

Summary Production of phospholipase D (PLD) by Streptoverticillium cinnamoneum immobilized within porous particles was investigated in repeated batch fermentation. The enzyme productivity in repeated batch fermentation was 2.2-fold that obtained in batch fermentation without immobilization, since many of the immobilized cells could be utilized as seed cells for each subsequent batch cycle.     

Isolation and characteristics of immobilized aminoacylase from Streptoverticillium olivoreticuli

Immobilization of aminoacylase from Streptoverticillium olivoreticuli by incorporation into acrylamide gel has been investigated. The data showed that the process should be carried out at constant pH. Thermal inactivation of the immobilized enzyme under the reaction conditions was studied. The kinetics of enzymatic stereospecific deacylation of N-acetyl-DL-phenylalanine was analyzed. The results of this study may be used in the synthesis of amino acid enantiomers.     

Stimulatory effect of ferrous ion on mildiomycin production by Streptoverticillium rimofaciens

The minimal concentration of Fe 2+ necessary for the maximal production of mildiomycin by Streptoverticillium rimo-faciens was about 8 mg Fe 2+ /ml at which the production of mildiomycin was about 10 times higher than that in the culture without added Fe 2+ . The culture with added Fe 2+ had a marked increase in NH 4 + assimilation, followed by an increase in mildiomycin production. The ferrous ion was incorporated during the cell growth and the uptake capacity of Fe 2+ was changed according to inoculum age and associated with the productivity of mildiomycin.     

拉达克轮丝菌TGase在大肠杆菌中的分子改造

【背景】谷氨酰胺转氨酶是一种能够催化酰基转移反应的酶,催化各种蛋白质分子之间或之内发生交联反应,在食品、化妆品、医药等领域具有重要的潜在价值。【目的】克隆来自拉达克轮丝菌(Streptoverticillium ladakanum) B1的谷氨酰胺转氨酶(TGase)基因并对其进行分子改造,使其在大肠杆菌中获得高效异源表达。【方法】分别克隆来自拉达克轮丝菌谷氨酰胺转氨酶的自身前导肽(pro)和除前导肽以外的成熟谷氨酰胺转氨酶(TGase)基因,以pET-22b为表达载体构建pro、TGase共表达和融合表达两种表达模式,在这两种表达模式的基础上进一步用定点突变的方法对成熟TGaseN端前4个氨基酸进行改造,检测不同表达模式以及突变对酶活的影响。【结果】当采用前导肽与TGase共表达时,可以直接得到活性形式的TGase,比酶活达到37.71 U/mg。在融合表达的基础上,将TGaseN端前3个氨基酸DSD突变为AAA,比酶活达到14.04U/mg,相较于原始表达模式提高了14.05%。【结论】前导肽与TGase共表达可以直接产生活性TGase,对于融合表达模式,合适位点的突变有利于提高TGase酶活。     

Production of Native-Type Streptoverticillium mobaraense Transglutaminase in Corynebacterium glutamicum

We previously observed secretion of active-form transglutaminase in Corynebacterium glutamicum by coexpressing the subtilisin-like protease SAM-P45 from Streptomyces albogriseolus to process the prodomain. However, the N-terminal amino acid sequence of the transglutaminase differed from that of the native Streptoverticillium mobaraense enzyme. In the present work we have used site-directed mutagenesis to generate an optimal SAM-P45 cleavage site in the C-terminal region of the prodomain. As a result, native-type transglutaminase was secreted.     

Intergeneric hydridization of the actinomycetes Streptoverticillium mycoheptinicum and Streptomyces coelicolor

Intergeneric crossing of the actinomycetes Streptoverticillium mycoheptinicum and Streptomyces coelicolor yielded recombinants which were mostly nonviable and unstable despite a relatively high frequency (10(-2)-10(-4)) at which their colonies appeared. The rare viable and stable recombinants were prototrophs. The structure of antibiotics in the hybrid cell may be modified as follows from the differences in the antibiotic activity of the LIA-973 hybrid and the parent strains.     

Isolation and Characterization of Immobilized Aminoacylase from Streptoverticillium olivoreticuli

Immobilization of aminoacylase from Streptoverticillium olivoreticuli by incorporation into acrylamide gel has been investigated. The data showed that the process should be carried out at constant pH. Thermal inactivation of the immobilized enzyme under the reaction conditions was studied. The kinetics of enzymatic stereospecific deacylation of N-acetyl-DL-phenylalanine was analyzed. The results of this study may be used in the synthesis of amino acid enantiomers.     

Medium design based on stoichiometric analysis of microbial transglutaminase production by Streptoverticillium mobaraense

A stoichiometric model was developed for the application of medium design in microbial transglutaminase production by Streptoverticillium mobaraense. The model avoids dealing with all the metabolic reactions involved by simply lumping them into a single reaction. With the help of measurement results, an analysis of the nutrients' roles, and biochemical knowledge of the microorganism, all stoichiometric coefficients in the model were calculated. These coefficients were used for medium design. With this designed medium, microbial transglutaminase activity was increased fourfold, compared to that in the basal medium. (c) 1996 John Wiley & Sons, Inc.     

茂原链轮丝菌转谷氨酰胺酶基因在大肠杆菌中高效表达

利用PCR方法从茂原链轮丝菌(Streptoverticillium mobaraense)基因组DNA扩增出微生物转谷氨酰胺酶(Microbial Transglutaminase,MTG)的基因片段,并构建表达质粒Pet-MTG。后者在大肠杆菌（Rosetta DE3）中得到高效表达,但表达的MTG存在于包涵体中。经洗涤、变性和复性,并以强阳离子交换层析纯化,获得了SDS-PAGE纯的MTG,并具有与天然酶几乎相同的比活性。此项工作为工业化生产MTG打下了基础。     

Phospholipase C inhibitor from Streptoverticillium mycoheptinicum

Streptoverticillium mycoheptinicum, a producer of the antifungal antibiotic mycoheptin, was found to produce an inhibitor of Clostridium perfringens phospholipase C. Dynamics of the enzyme accumulation in the culture liquid filtrate was studied. A technique was developed for purification of the inhibitor, which includes adsorption, selective precipitation, ultrafiltration, gel chromatography and isoelectric focusing. The inhibitor was found to be of the peptide nature with the molecular weight of 3500-4000 and to exist in two isoforms with the isoelectric points of 8.15 and 8.50.     

转谷氨酰胺酶的分子生物学与基因工程

来源于微生物特别是轮枝链霉菌的转谷氨酰胺酶是一种重要的酶制剂,在食品工业中有着广泛的应用前景。本综述了近年来对转谷氨酰胺酶的分子生物学研究成果,以及对其进行基因工程改造的最新进展,讨论了其进一步的研究发展方向。笔认为采用基因工程生产重组转谷氨酰胺酶是解决目前酶价高昂和来源困难问题的一个大有希望的办法。     

Absolute stereochemistry of the strevertenes

The CD exciton chirality method was applied to determine the absolute stereochemistry of the strevertenes, antifungal pentaene macrolides produced by Streptoverticillium sp. LL-30F848. The CD difference spectrum of strevertene A methyl ester 15-dimethylaminobenzoate showed a positive couplet between the dimethylaminobenzoate and the pentaene chromophores, and therefore established the 15R configuration. Thus, by considering the relative configurations of the remaining stereogenic centers as derived from X-ray crystallography and ROESY experiments, the absolute stereochemistry of the strevertenes is established as 2R, 3S, 5S, 7S, 11R, 13R, 14R, 15R, 26S and 27R.