Streptomyces globosus DK15 and Streptomyces ederensis ST13 as new producers of factumycin and tetrangomycin antibiotics

ABSTRACT Fifty seven soil-borne actinomycete strains were assessed for the antibiotic production. Two of the most active isolates, designed as Streptomyces ST-13 and DK-15 exhibited a broad range of antimicrobial activity and therefore they were selected for HPLC fractionation against the most suppressed bacteria Staphylococcus aureus (ST-13) and Chromobacterium violaceum (DK-15). LC/MS analysis of extracts showed the presence of polyketides factumycin (DK15) and tetrangomycin (ST13). The taxonomic position of the antibiotic-producing actinomycetes was determined using a polyphasic approach. Phenotypic characterization and 16S rRNA gene sequence analysis of the isolates matched those described for members of the genus Streptomyces. DK-15 strain exhibited the highest 16S rRNA gene sequence similarity to Streptomyces globosus DSM-40815 (T) and Streptomyces toxytricini DSM-40178 (T) and ST-13 strain to Streptomyces ederensis DSM-40741 (T) and Streptomyces phaeochromogenes DSM-40073 (T). For the proper identification, MALDI-TOF/MS profile of whole-cell proteins led to the identification of S. globosus DK-15 (accession number: KX527570) and S. ederensis ST13 (accession number: KX527568). To our knowledge, there is no report about the production of these antibiotics by S.globosus and S. ederensis, thus isolates DK15 and ST13 identified as S. globosus DK-15 and S.ederensis ST-13 can be considered as new sources of these unique antibacterial metabolites.

Impact of Lysophosphatidylcholine on the Plasminogen Activator System in Cultured Vascular Smooth Muscle Cells

The balance between tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor type 1 (PAI-1) regulates fibrinolysis. PAI-1 expression increases in atherosclerotic arteries and vascular smooth muscle cells (VSMCs) are one of major constituents of atheroma. We investigated the impact of lysophosphatidylcholine (lysoPC), an active component of oxidized low-density lipoprotein, on the plasminogen activator system of the rat VSMCs. The lysoPC stimulated the protein and gene expressions of PAI-1 but did not affect the protein expression of t-PA. Fibrin overlay zymography revealed that lysoPC increased the activity of PAI-1 in the conditioned media, while concurrently decreasing that of free t-PA. Vitamin E inhibited the lysoPC-induced PAI-1 expression. Further, lysoPC increased the intracellular reactive oxygen species (ROS) formation. Caffeic acid phenethyl ester, an inhibitor of NF-kappaB, blocked this lysoPC effect. Indeed, lysoPC induced the NF-kappaB-mediated transcriptional activity as measured by luciferase reporter assay. In addition, genistein, an inhibitor of protein-tyrosine kinase (PTK), diminished the lysoPC effect, while 7,12-dimethylbenz[a]anthracene, a stimulator of PTK, stimulated PAI-1 production. In conclusion, lysoPC does not affect t-PA expression but induces PAI-1 expression in the VSMC by mediating NF-kappaB and the genistein-sensitive PTK signaling pathways via oxidative stress. Importantly, lysoPC stimulates the enzyme activity of PAI-1 and suppresses that of t-PA.

Study on cow ghee versus soybean oil on 7,12-dimethylbenz(a)-anthracene induced mammary carcinogenesis & expression of cyclooxygenase-2 & peroxisome proliferators activated receptor- γ in rats.

Background & objectives Breast cancer is a leading cause of cancer death in women; dietary fat is the one of the factors that influences its incidence. In the present study we investigated the effect of feeding cow ghee versus soybean oil on 7,12-dimethylbenz(a)anthracene (DMBA) induced mammary cancer in rat and expression of cyclooxygenase-2 and peroxisome proliferators activated receptor- γ (PPAR-γ) in mammary gland. Methods Two groups of 21 day old female rats (30 each) were fed for 44 wk diet containing cow ghee or soybean oil (10%). The animals were given DMBA (30mg/kg body weight) through oral intubation after 5 wk feeding. Another two groups (8 each) fed similarly but not given DMBA served as control for the gene expression study. Results In DMBA treated groups, the animal fed soybean oil had higher tumour incidence (65.4%), tumour weight (6.18 g) and tumour volume (6285 mm3) compared to those fed cow ghee (26.6%, 1.67 g, 1925 mm3, respectively). Tumour latency period was 23 wk on soybean oil compared to 27 wk on cow ghee. Histological analysis of tumours showed that the progression of carcinogenesis was more rapid on soybean oil than on cow ghee. The expression of cyclooxygenase-2 was observed only in DMBA treated rats and it was significantly less on cow ghee than on soybean oil. The expression of PPAR-γ was significantly more on cow ghee than on soybean oil. Interpretation & conclusions Our results show that dietary cow ghee opposed to soybean oil attenuates mammary carcinogenesis induced by DMBA; and the effect is mediated by decreased expression of cyclooxygenase-2 and increased expression of PPAR-γ in the former group.

In vivo alternative testing with zebrafish in ecotoxicology

Although rodents have previously been used in ecotoxicological studies, they are expensive, time-consuming, and are limited by strict legal restrictions. The present study used a zebrafish (Danio rerio) model and generated data that was useful for extrapolating toxicant effects in this system to that of humans. Here we treated embryos of the naive-type as well as a transiently transfected zebrafish liver cell line carrying a plasmid (phAhREEGFP), for comparing toxicity levels with the well-known aryl hydrocarbon receptor (AhR)-binding toxicants: 3,3',4,4',5-pentachlorobiphenyl (PCB126), 2,3,7,8-tetrachlorodibenzo-p-dioxin, and 3-methylcholanthrene. These toxicants induced a concentration-dependent increase in morphological disruption, indicating toxicity at early life-stages. The transient transgenic zebrafish liver cell line was sensitive enough to these toxicants to express the CYP1A1 regulated enhanced green fluorescent protein. The findings of this study demonstrated that the zebrafish in vivo model might allow for extremely rapid and reproducible toxicological profiling of early life-stage embryo development. We have also shown that the transient transgenic zebrafish liver cell line can be used for research on AhR mechanism studies.

Enhancement of urinary elimination of 3-bromobenzanthrone metabolites by oral supplementation of ascorbic acid in guinea pigs / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>3-Bromobenzanthrone (3-BBA), an anthraquinone intermediate dye, is extensively used in textile industry. Since, our prior studies have shown that 3-BBA caused significant depletion of ascorbic acid (AsA) levels, the effect of exogenous supplementation of AsA on the urinary elimination of 3-BBA metabolites was investigated.</p><p><b>METHOD</b>Guinea pigs were treated with single oral dose of 3-BBA (50 mg/kg b. wt.) in groundnut oil while another group was treated with single oral dose of 3-BBA (50 mg/kg b. wt.) along with 3 day prior and post oral supplementation of AsA. Control groups were either treated with groundnut oil or AsA alone. Urine from individual animals was collected, extracted and analysed on HPTLC.</p><p><b>RESULTS</b>The highest elimination of 3-BBA (75 microg) was found to be in 0-24 h urine fraction which decreased to 18 microg and 5 microg in the two subsequent 24 hourly fractions of urine. Exogenous supplementation of AsA increased the total urinary elimination of 3-BBA by almost 77%. A total of 10 fluorescent metabolites excluding the parent compound were eliminated in the urine of guinea pigs treated with 3-BBA. Densitometric scanning of chromatogram showed different peaks at Rf 0.18, 0.22, 0.27, 0.34, 0.40, 0.48, 0.56, 0.66, 0.72, 0.80, and 0.95 which were eliminated and marked as urinary metabolite 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11 respectively. AsA not only significantly enhanced the elimination of 3-BBA metabolites but also modified the pattern of metabolites drastically in 0-6 h, 6-24 h and 24-48 h urine fractions.</p><p><b>CONCLUSION</b>These results indicate that AsA may be useful in protecting the toxicity of 3-BBA by fascilitating the urinary metabolite(s) excretion of 3-BBA.</p>

Abnormal pattern of lung functions in rubber factory workers.

The influence of suspended particulate matter, benzo(e) pyrene, benzo(e) pyrene and benzo(a) anthracene concentration on pulmonary lung functions ie, residual volume, total lung capacity, residual volume/total lung capacity, forced residual capacity were studied in 667 rubber factory workers during 1990-91. The respirable fraction of the particulate size (< 0.5 micron) showed high mean concentration of suspended particulate matter, benzo(a) pyrene, benzo(e) pyrene and benzo(a) anthracene in the compounding section (group III), when compared with vulcanising (group II) and packing loading (group I) units. While comparing the lung functions amongst these groups, the higher results of residual volume, residual volume/total lung capacity ratio, forced respiratory capacity and lower values of total lung capacity were observed in group III workers as compared with other two groups. And also these results seem to be correlated with the high pollutant concentrations to which group III workers were exposed, and reflect a clear combination of obstructive and restrictive pattern of lung functions in them.