Laboratory of Bacterial Genetics and Environmental Biotechnology, Department of Microbiology, Goa University, Taleigao Plateau, Goa, 403206, India.
Field Unit, ICMR-National Institute of Malarial Research, DHS Building, Campal, Panaji, Goa, 403206, India.
Arch Microbiol. 2022 Jun 7;204(7):372. doi: 10.1007/s00203-022-02977-9.
Selenite reducing bacterial strain (GUSDM4) isolated from Mandovi estuary of Goa, India was identified as Halomonas venusta based on 16S rRNA gene sequence analysis. Its maximum tolerance level for sodium selenite (NaSeO) was 100 mM. The 2, 3-diaminonaphthalene-based spectroscopic analysis demonstrated 96 and 93% reduction of 2 and 4 mM NaSeO respectively to elemental selenium (Se) during the late stationary growth phase. Biosynthesis of Se nanoparticles (SeNPs) commenced within 4 h during the log phase, which was evident from the brick red color in the growth medium and a characteristic peak at 265 nm revealed by UV-Vis spectrophotometry. The intracellular periplasmic synthesis of SeNPs in GUSDM4 was confirmed by transmission electron microscopy (TEM). Characterization of SeNPs by X-ray crystallography, TEM and energy-dispersive X-ray analysis (EDAX) clearly demonstrated spherical SeNPs of 20-80 nm diameter with hexagonal crystal lattice. SeNPs (0.8 and 1 mg/L) primed seeds under arsenate [As(V)] stress showed increase in shoot length, root length and biomass by 1.4-, 1.5- and 1.1-fold respectively, as compared to As(V) primed seeds alone. The proline and phenolic content in seeds primed with SeNPs under arsenate stress showed alleviated levels proving its ameliorative potential. SeNPs also demonstrated anti-biofilm activity at 20 µg/mL against human pathogens which was evident by scanning electron microscopic (SEM) analysis. SeNPs interestingly revealed mosquito larvicidal activity also. Therefore, these studies have clearly demonstrated amazing potential of the marine bacterium, Halomonas venusta in biosynthesis of SeNPs and their applications as ameliorative, anti-biofilm and mosquito larvicidal agents which is the first report of its kind.
从印度果阿的曼多维河口分离出的亚硒酸盐还原细菌(GUSDM4),根据 16S rRNA 基因序列分析,被鉴定为盐沼盐单胞菌。它对亚硒酸钠(NaSeO)的最大耐受水平为 100mM。基于 2,3-二氨基萘的光谱分析表明,在晚期稳定生长阶段,分别将 2mM 和 4mM 的 NaSeO 还原为 96%和 93%的元素硒(Se)。在对数生长期内,4 小时内开始合成硒纳米颗粒(SeNPs),这可以从生长培养基中的砖红色和紫外可见分光光度法显示的 265nm 处的特征峰看出。通过透射电子显微镜(TEM)证实了 GUSDM4 中细胞周质内合成 SeNPs。通过 X 射线晶体学、TEM 和能量色散 X 射线分析(EDAX)对 SeNPs 的表征清楚地表明,SeNPs 为 20-80nm 直径的球形,具有六方晶格。在砷酸盐[As(V)]胁迫下,用硒纳米颗粒(0.8 和 1mg/L)引发种子,与单独用 As(V)引发种子相比,分别使芽长、根长和生物量增加 1.4 倍、1.5 倍和 1.1 倍。在砷酸盐胁迫下用 SeNPs 引发的种子中的脯氨酸和酚含量显示出缓解水平,证明了其改善潜力。SeNPs 在 20μg/mL 时对人类病原体也表现出抗生物膜活性,这可以通过扫描电子显微镜(SEM)分析看出。有趣的是,SeNPs 还表现出杀蚊幼虫活性。因此,这些研究清楚地表明了海洋细菌盐沼盐单胞菌在合成 SeNPs 及其作为改善剂、抗生物膜剂和杀蚊幼虫剂方面的惊人潜力,这是此类研究的首例报道。