A New Compound Isolated from a Bioactive Streptomycete

A new compound, named (S)-α-acetylamino-β-(3-indole)propanol (1) was isolated, along with two known compounds teleocidin B1 and emycin B from culture broth of a streptomycete strain YIM33176 (streptomyces pleomorphus). The structure of 1 was determined by detailed spectroscopic investigation.

Streptophage-mediated control of off-flavour taint producing streptomycetes isolated from barramundi ponds

Off-flavour taint of aquaculture products is a global issue reducing consumer confidence in the farmed produce as they are taken up via the gills of fish,and deposited in the lipids of the animal.If the fish are not purged,resulting undesirable muddy earthy flavour taint can be tasted by consumers.These undesirable flavour and odour is caused by the terpenoid compounds namely geosmin and 2-methylisoborneol,produced as secondary metabolites by certain bacteria including the cyanobacteria and actinomycetes.Current strategies to remediate the problem rely on treating the symptoms not the cause and involve the use of time consuming purging methods and costly chemicals.Biological control using bacteriophages,specific to the problem causing bacteria,offers a natural alternative to chemical control,which might reduce further complications of copper based algaecides and its subsequent implications on water quality.In an adaptation of such biological control approach streptomycetes isolated from barramundi ponds were tested for their susceptibility to streptophages to understand whether host destruction via phage lysis would subsequently eliminate off-flavour taint productions by these isolates.Following the determination of the streptophage susceptibility of the isolates one of the most odourous streptomycete species(USC-14510)was selected to be tested further using different pond simulations resembling real-life applications.Geosmin was tested as the indicator of off-flavour taint production and as it has been previously reported that the cyanobacteria-actinomycete interactions occurring in ponds result in even greater levels of geosmin and 2-methylisoborneol,the geosmin levels for the isolate in the presence of cyanobacteria and streptophages were also tested.Findings indicated that the highly odourous Streptomyces species(USC-14510)once infected with streptophages,can lose its capacity to produce off-flavour taints.Pond simulation studies also revealed geosmin production was significantly reduced when streptophages were introduced into the pond water where streptomycete species were grown.The bacteriophage control method developed in the presented study might again confirm significant potential for the bacteriophage-mediated remediation strategy to be adapted by the aquaculture industry.

Isolation, identification, and cytotoxicity of a new isobenzofuran derivative from marine Streptomyces sp. W007

A new isobenzofuran derivative( 1) was isolated from the marine Streptomyces sp. W007 and its structure was determined through extensive spectroscopic analyses, including 1D-NMR, 2D-NMR, and ESI-MS. The absolute configuration of compound 1 was determined by a combination of experimental analyses and comparison with reported data, including biogenetic reasoning, J-coupling analysis, NOESY, and 1 H- 1 HCOSY. Compound 1 exhibited no cytotoxicity against human cells of gastric cancer BGC-823, lung cancer A549, and breast cancer MCF7.

Strain and Culture Medium Optimization for Production Enhancement of Prodiginines from Marine-Derived Streptomyces sp. GQQ-10

A mutant (GQQ-M6) of a Sponge-Derived streptomyces sp. GQQ-10 obtained by UV-induced mutation was used for producing prodiginines (PGs). Single factor experiments and orthogonal array design (OAD) methods were employed for medium optimization. In the single factor method, the effects of soluble starch, glucose, soybean flour, yeast extract and sodium acetate on PGs production were investigated individually. In the subsequent OAD experiments, the concentrations of these 5 key nutritional components combined with salinity were further adjusted. The mutant strain GQQ-M6 gave a 2.2-fold higher PGs production than that of the parent strain; OAD experiments offered a PGs yield of 61mg L-1, which was 10 times higher than that of the initial GQQ-10 strain under the original cultivation mode.

影响链霉菌原生质体形成、再生的因素

本文报道生长培养基成份,菌丝生育期,溶菌温度及再生培养基成份等对庆丰链霉菌,吸水链霉菌井冈变种原生质体形成和再生的影响,结果表明: 1.生长培养基中添加适量甘氨酸,和/或蔗糖,能增加菌丝细胞壁被溶菌酶消化的敏感性。2.对数生长期菌丝比静止期菌丝原生质体的再生活性高得多。3.菌丝溶解温度庆丰链霉菌以28℃为宜,吸水链霉菌井冈变种则以32℃为最适。4.再生培养基中高渗稳定剂的浓度对原生质体再生影响很大,对吸水链霉菌井冈变种来说,再生培养基R_2YE中的蔗糖以0.3M为宜,R_3中的琥珀酸钠以0.2M为宜。文中并对甘氨酸,蔗糖的作用机理及不同链霉菌原生质体制剂中含有不同比例的渗透敏感单位(即真正原生质体)的可能原因进行了讨论。

Evaluation of fermentation conditions triggering increased antibacterial activity from a near-shore marine intertidal environment-associated Streptomyces species

A near-shore marine intertidal environment-associated Streptomyces isolate(USC-633)from the Sunshine Coast Region of Queensland,Australia,cultivated under a range of chemically defined and complex media to determine optimal parameters resulting in the secretion of diverse array of secondary metabolites with antimicrobial properties against various antibiotic resistant bacteria.Following extraction,fractioning and re-testing of active metabolites resulted in persistent antibacterial activity against Escherichia coli(Migula)(ATCC 13706)and subsequent Nuclear Magnetic Resonance(NMR)analysis of the active fractions confirmed the induction of metabolites different than the ones in fractions which did not display activity against the same bacterial species.Overall findings again confirmed the value of One StraineMany Compounds(OSMAC)approach that tests a wide range of growth parameters to trigger bioactive compound secretion increasing the likelihood of finding novel therapeutic agents.The isolate was found to be adaptable to both marine and terrestrial conditions corresponding to its original nearshore marine intertidal environment.Wide variations in its morphology,sporulation and diffusible pigment production were observed when different growth media were used.