2014.07.21【英译中】SCI 连载之八

小妮丫头 (流火) 路人甲
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发表于:2014-07-21 23:52 [只看楼主] [划词开启]

2014.07.21【英译中】SCI 连载之八


The ARC2 series of molecules not only enhanced the yields of known antibiotics, but induced the production of as yet unidentified compounds in Streptomyces peuceticus, compounds that could not be detected in the absence of ARC2 (Craney et al.2012). Conceivably, the expression levels of the genes encoding the enzymes to synthesize these compounds are very low (i.e., nearly but not entirely silent), so that reinforcement of the biosynthetic process by an efficient supply of substrate made possible their detection. Alternatively, some other yet-unknown mechanism may be involved in the observed phenomenon. Theoretically, this approach may be enhanced by combination with the transcription-associated approaches (Ochi and Okamoto2012). It may be possible to develop similar approaches for other classes of antibiotics, such as aminoglycosides and nonribosomal peptides, to access the full spectrum of secondary metabolites.

ARC2系列的分子不仅能够增强已知的抗生素,还能诱导Streptomyces peuceticus中还未鉴定确认的化合物的产生,因为这些化合物在缺少ARC2的情况下不能被检测得到。可以想象地,编码合成这些化合物的酶的基因表达很弱(如几乎但不是全部沉默),所以通过提供有效的底物对生物合成过程进行强化使这些化合物能够有效检测出来。另外一种,在观察到的现象当中应该有一些其他还不甚清楚的机制参与其中。理论上说来,多联转录方法的结合能够加强这种方法。这让其他类抗生素运用类似的方法评估次级代谢物的广谱性成为可能,例如氨基糖苷类和非核糖体肽类

 

Approach from cell-to-cell interactions

运用胞间作用的方法

Co-culture is an effective method of inducing the production of cryptic metabolites. Although some co-culture methods have been reported, these methods are often specific to two bacterial strains. This limitation may be overcome by a novel fermentation method, the combined culture method, involving the co-culture of two bacterial strains (Onaka et al. 2011). Mycolic acid-containing bacteria could influence the biosynthesis of cryptic natural products in Streptomyces spp. The production of red pigment by S. lividans was induced by co-culture with Tsukamurella pulmonis, a mycolic acidcontaining bacterium. Importantly, co-culture with T. pulmonis improved or inhibited natural product biosynthesis in 88 % of the Streptomyces strains isolated from soil: the production of new secondary metabolites was detected in 37 % of strains, while increased metabolite production was detected in 55 % of strains. The other mycolic acid-containing bacteria, Rhodococcus erythropolis and Corynebacterium glutamicum, improved or inhibited biosynthesis in 87 and 90 % of the Streptomyces strains, respectively: the production of new secondary metabolites was detected in 32 and 24 % of strains, respectively. Co-culture of T. pulmonis with Streptomyces endus led to the identification of a novel antibiotic, alchivemycin A. The addition of mycolic acid into the medium of pure S. lividans cultures had no effect on antibiotic production, suggesting that mycolic acid localized to the outer cell layer of the inducer bacterium affected secondary metabolism in Streptomyces, with this activity resulting from the direct cell-to-cell interaction of the two bacterial strains (Onaka et al. 2011). This method is also scalable for inducing the production of cryptic antibiotics, as it only involves the addition of a mycolic acid-containing bacterium to a pure culture of an actinomycete.

共培养是一种能有效诱导隐含代谢物的产生的方法。虽然一些共培养的方法已经被报道出来,这些方法常在两种细菌中具有特异性。这种限制能够被一种新兴发酵方法所克服——联合培养方法,其中就包括共培养的两种细菌。含有霉菌酸的细菌能够影响Streptomyces 属中隐藏的天然产物的合成。S. lividans中红色素的产生就是被共培养菌Tsukamurella pulmonis所诱导,这种菌就是一种含有霉菌酸的细菌。重要地是,土壤中分离的Streptomyces菌在与T. pulmonis共培养后,88%Streptomyces菌中天然产物的合成受到了提高或者抑制:37%Streptomyces菌中检测到了新的次级代谢产物的产生,55%Streptomyces菌中检测到了代谢产物产量增加。其他含有霉菌酸的细菌,Rhodococcus erythropolis Corynebacterium glutamicum分别提高或者抑制Streptomyces菌中的生物合成:新的次级代谢产物在32 24 % Streptomyces菌中分别检测得到。Streptomyces endus菌与T. pulmonis菌共培养得到一种新的抗生素——alchivemycin A。对S. lividans纯培养物中添加霉菌酸对抗生素产量没有任何影响,说明霉菌酸影响Streptomyces菌的次级代谢机制仅局限于诱导细菌的外侧细胞层,因为两种细菌的直接胞间作用的活性可以说明。这种方法同样可以用来诱导隐藏的抗生素,因为它只包括在放线菌纯培养物当中添加霉菌酸的细菌这种情况下。

分类: 英语

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