Sponge-Associated Bacteria Produce Non-cytotoxic Melanin Which Protects Animal Cells from Photo-Toxicity
Sponge-Associated Bacteria Produce Non-cytotoxic Melanin Which Protects Animal Cells from Photo-Toxicity
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DOI：
10.1007/s12010-017-2453-0
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发表时间：
2017-09-01
影响因子：
3
通讯作者：
Nair, Shanta
中科院分区：
文献类型：
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作者：
Vijayan, Vijitha;Jasmin, Chekidhenkuzhiyil;Nair, Shanta
黑色素是在许多生物体中发现的光保护聚合物。我们的研究表明，与深色海绵（Haliclona pigmentifera，Sigmadocia pumila，Fasciospongia cavernosa，Spongia officinalis和Callypongia diffusa）相关的细菌分泌非细胞毒性黑色素，具有保护动物细胞免受光毒性的抗氧化活性。在筛选的156个细菌菌株中，22个产生黑色素，并且这些产生黑色素的细菌（MPB）被鉴定为弧菌属，普罗威登斯菌属，芽孢杆菌属、希瓦氏菌属，葡萄球菌属，动球菌属，盐球菌属，溶藻弧菌海洋微生物参考设施（MMRF）534（50 mg ml（-1））表现出最大的黑色素产生，其次是哈氏弧菌MMRF 535（40 mg ml（-1））和MMRF 546（30 mg ml（-1））的两个分离株。通过途径抑制实验和红外光谱分析，我们鉴定了分泌到MPB培养基中的黑色素为1，8-二羟基萘黑色素。细菌黑色素对小鼠成纤维细胞L929细胞和盐水虾无细胞毒性，浓度分别高达200和500 ppm。细菌黑色素在非常低的浓度（IC 50 -9.0 ppm）下显示出抗氧化活性，并且在50 ppm下，黑色素保护L929细胞免受UV诱导的细胞内活性氧应激。我们的研究提出海绵相关细菌作为具有抗氧化潜力的非细胞毒性黑色素的潜在来源。
Melanin is a photo-protective polymer found in many organisms. Our research shows that the bacteria associated with darkly pigmented sponges (Haliclona pigmentifera, Sigmadocia pumila, Fasciospongia cavernosa, Spongia officinalis, and Callyspongia diffusa) secrete non-cytotoxic melanin, with antioxidant activity that protects animal cells from photo-toxicity. Out of 156 bacterial strains screened, 22 produced melanin and these melanin-producing bacteria (MPB) were identified as Vibrio spp., Providencia sp., Bacillus sp., Shewanella sp., Staphylococcus sp., Planococcus sp., Salinococcus sp., and Glutamicibacter sp. Maximum melanin production was exhibited by Vibrio alginolyticus Marine Microbial Reference Facility (MMRF) 534 (50 mg ml(-1)), followed by two isolates of Vibrio harveyi MMRF 535 (40 mg ml(-1)) and MMRF 546 (30 mg ml(-1)). Using pathway inhibition assay and FT-IR spectral analysis, we identified the melanin secreted into the culture medium of MPB as 1,8-dihydroxynaphthalene-melanin. The bacterial melanin was non-cytotoxic to mouse fibroblast L929 cells and brine shrimps up to a concentration of 200 and 500 ppm, respectively. Bacterial melanin showed antioxidant activity at very low concentration (IC50-9.0 ppm) and at 50 ppm, melanin protected L929 cells from UV-induced intracellular reactive oxygen stress. Our study proposes sponge-associated bacteria as a potential source of non-cytotoxic melanin with antioxidant potentials.