Medium optimization for enhanced production of cytosine-substituted mildiomycin analogue (MIL-C) by Streptoverticillium rimofaciens ZJU 5119 / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Cytosine-substituted mildiomycin analogue (MIL-C) was produced effectively by supplementing cytosine into the culture of Streptoverticillium rimofaciens. In order to improve the yield of MIL-C, statistically-based experimental designs were applied to optimize the fermentation medium for S. rimofaciens ZJU 5119. Fifteen culture conditions were examined for their significances on MIL-C production using Plackett-Burman design. The Plackett-Burman design and one-variable-at-a-time design indicated that glucose and rice meal as the complex carbon sources, and peanut cake meal and NH4NO3 as the complex nitrogen sources were beneficial for MIL-C production in S. rimofaciens ZJU 5119. The results of further central composition design (CCD) showed that the optimal concentration of glucose, rice meal and peanut cake meal were 18.7 g/L, 64.8 g/L and 65.1 g/L, respectively. By using this optimal fermentation medium, the MIL-C concentration was increased up to 1336.5 mg/L, an approximate 3.8-fold improvement over the previous concentration (350.0 mg/L) with un-optimized medium. This work will be very helpful to the large-scale production of MIL-C in the future.

High expression of mirobial transglutaminase gene from Streptoverticillium mobaraense in Escherichia coli / 生物工程学报

The microbial transglutamunase (MTG) gene was amplified from the genomic DNA of Streptoverticillium mobaraensea by using PCR and inserted into pET vector to construct the expression plasmid called pET-MTG. The pET-MTG was transfected into E. coli (Rosetta DE3) and the MTG protein was found to be highly expressed as inclusion bodies. The inclusion bodies were isolated and subjected to denaturation and re-naturation, followed by strong cation ion-exchange chromatography to purify the expressed MTG. The specific activity of purified MTG was close to that of native MTG. Taken together, this study might provide a base for the industrial production of microbial transglutaminase.

Construction of efficient conjugal plasmids between Escherichia coli and Streptomycetes / 生物工程学报

Conjugal plasmid pGH112 has been developed based on the replicons of Streptomyces coelicolor plasmid SCP2 and E. coli ColE. The plasmid contains ampicilin resistance gene(amp) for selection in E. coli and thiostrepton resistance gene (tsr) for selection in Streptomycetes, and a 0.76 kb oriT fragment of (IncP) RK2. Conjugal transfer of pGH112 was performed from E. coli to S. coelicolor A3(2), S. avermitilis, S. lividans TK54, S. toxytricini NNRL15443, S. venezuelae ISP5230 and Sacc. erythraea by conjugation, results show that the plasmid was able to transfer efficenctly from E. coli to Streptomycetes, was stably inherited in the recipients. pGH113 was constructed from pGH112 by combining the constitutive ermE promoter with green fluorescent protein gene(gfp).

Atividade antimicrobiana e antitumoral de Streptoverticillium sp (DAUFPE 13.729) / Antimicrobial and antitumoral activities of Streptoverticillium sp (DAUFPE 13.729)

Streptoverticillium sp, bactéria pertencente a família Streptomycetaceae, foi isolada de amostras de solo do câmpus da Universidade Federal do Pernambuco, e destacou-se pela atividade antibacteriana e antifúngica de seus matabólitos secundários. O extrato etanóico bruto foi submetido ao fracionamento cromatográfigo. Das substâncias isoladas, duas apresentaram atividade antimicrobiana em relação a sete espécies de Candida. Em testes biológicos realizados em camundongos, determinou-se que a maior dose do extrato bruto na qual não houve óbitos foi de 150 mg/kg e todos os animais morreram com a administração de 600 mg/kg. Para o extrato etanóico de Streptoverticillium sp observou-se IC50 de 13 ug/mL e taxa de inibição tumoral igual a 61,5 por cento para o carcinoma de Ehrlich e 75 por cento em animais com sarcoma 180.

Studies on the asparaginolytic activity of the brown-pigmented streptomycetes

Twenty-eight brown-pigmented streptomycetes were isolated from different fertile Egyptian soils. Screening was carried out according to their asparaginolytic activity under static culture condition on glycerol- L-asparagine [GA] medium. Results revealed that FS-39 isolate gave the highest asparaginolytic activity. Therefore, it was selected and subjected to complete identification. The cultural, morphological and physiological characteristics of this isolate indicated that it belongs to Streptomyces phaeochromogenes. The effects of nutritional and environmental conditions on the asparaginase activity of Streptomyces phaeochromogenes FS-39 were studied. Data revealed that the maximal, yield of L-asparaginase from this strain can be obtained by growing it on glycerol-L-asparagine yeast extract [GAY] medium containing [w/v] 2.0% Glycerol, 0.2% L-asparagine, 0.1% yeast extract, 0.1% K[2]HPO[4].3H20, 0.0001% FeSO[4].7H[2]0, 0.0001% MnCl[2]. 4H[2]0, 0.0001% ZnSO[4].7H[2]O which was initially adjusted to pH 7.0, inoculated by 2% [v/v] of homogenized spore suspension [containing approximately 3.2x10[7] spores/ml] of 3 days old culture on starch nitrate medimi and incubated at 30°C for 7 days under static culture condition

Effect of dissolved oxygen levels on biosynthesis of aureofungin by Streptoverticillium cinnamoneum var. terricola.

Biosynthesis of aureofungin by Streptoverticillium cinnamoneum var, terricola was found to be an oxygen dependent reaction. An accelerated rate of aureofungin production, along with a better yield coefficient were obtained under conditions of enhanced aeration during fermentation. A higher oxygen transfer rate was found to stimulate aureofungin A, and suppresses aureofungin B formation.

Streptoverticillium acido-carbonicum sp. nov.

A new species of Streptoverticillium assignable to biverticillate series, isolated from coal mine soil, Kothagudem (A. P.) is described. It grows from pH 4.5-6.0 with an optimum at pH 5.0 and temperature 37 degrees C. Its growth characters on differential media and utilization of carbon compounds are presented.