Ecological implications of trace metals in seaweeds: Bio-indication potential for metal contamination in Wandoor, South Andaman Island

AbstractConcentration levels of Mn, Pb, Zn, Cd, Cu and Cr in six seaweed samples (Acetabularia calyculus, Corallina sp., Galaxura marginata, Sargassum duplicatum, Sargassum swartzi and Dictyota bartayresiana) were determined from Wandoor, south Andaman Island. Metals were extracted from sample homogenates and quantified by atomic absorption spectrometry. In the present investigation, heavy metal concentration levels in the following order: Mn>Pb>Cd. It is observed that Zn was only present in free floating brown seaweed S. swartzi. Cu and Cr did not show its presence in any of the seaweeds that was sampled. Metal pollution index (MPI) of six seaweed species were observed in the following decending order: A. calyculus>Corallina sp.>D. bartayresiana>G. marginata>S. duplicatum>S. swartzi. Results showed that chlorophyta, A. calyculus contained the highest concentration of heavy metals as compared to other algal species. One-way analysis of variance (ANOVA) showed that the concentration of metals was significantly different (p<0.05) with respect to different species around the study area

Isolation and cellular fatty acid profile analyzation of two marine bioluminescent bacteria

192-195Two luminescent bacterial strains KOOS1 and KOOS2 isolated from surface mucus of Octopus sp. collected from Andaman were identified by their cellular fatty acid composition analyzation with the help of Microbial Identification system (MIDI). SIM indexes obtained for these isolated strains were 0.772 (KOOS1) and 0.754 (KOOS2) respectively and were identified as Photobacterium damselae and Vibrio fischeri. Major fatty acids found in Photobacterium damselae were Saturated: Dodecanoic acid (C12:0), Tetradecanoic acid (C14:0), Pentadecanoic acid (C15:0), Hexadecanoic acid (C16:0), Heptadecanoic acid (C17:0) and Octadecanoic acid (C18:0); and Unsaturated: 3-hydroxy-9-methyl decanoic acid (C11:0iso 3OH), 3-hydroxydodecanoic(C12:0 3OH), C16:1ω5c, Oleic acid (C18:1ω9c) and C18:1ω5c.In Vibrio fischeri Saturated: C12:0, Tridecanoic acid (C13:0), C15:0, C16:0, C17:0 and C18:0; and Unsaturated: C11:0iso 3OH,2-hydroxydodecanoic (C12:0 2OH), C12:03OH, C13:0iso, C14:0iso, C15:0iso, C15:0anteiso, C16:0iso, C17:0iso, C16:1ω5c, C15:0iso3OH, C17:1 ω8c and C17:1ω6c were found. Cyclopropane acids have not been detected in both Photobacterium damselae and Vibrio fischeri

Non-species specific composition of bioluminescent bacteria in non-bioluminescent squid Sepioteuthis lessoniana (Lesson, 1830)

975-981The present study investigated luminous bacterial species composition from non-bioluminescent big fin reef squid, Sepioteuthis lessoniana for the first time and revealed a new insight on the occurrence of five distinct luminous bacterial species such as Vibrio harveyi, V. campbellii, V. vulnificus, V. alginolyticus and Photobacterium damselae indicating the association of non-species specific luminous bacterial composition in S. lessoniana. Fourteen potential luminescent bacterial strains were isolated from S. lessoniana and identified based on morphological and biochemical tests. Majority of the isolates had produced industrially important extracellular enzymes- protease, chitinase and lipases. Antibiogram assay revealed that majority of the isolates were sensitive to various antibiotics and resistant to Ampicillin and Penicillin. While isolates CS1S and CS5S were sensitive to Ampicillin and Penicillin; and CS4G was sensitive to Penicillin. The present study is the first report to demonstrate luminous bacterial species diversity and extracellular enzyme production capabilities, and their antibiogram profile from big fin reef squid S. lessoniana

Assessment of antibacterial efficacy of the methanolic extract of Bacillus vietnamensis PBChS1 isolated from marine sediments of Chidiyatapu coast, South Andaman

1009-1017Marine bacteria are of extensive significance as new ‘budding springs’ of a vast number of organic active artefacts. Till now, only a fraction of microorganisms have been scrutinized for bioactive metabolites, yet a colossal sum of these metabolites with unique structural drafts remains untouched and unexploited. In this respect, the species of Bacillus vietnamensis was isolated from the marine sediments of Chidiyatapu coast, South Andaman and characterized by both phenotypic and genotypic methods. The anti-oxidative activities of the methanolic extract were determined by the estimation of TPC (Total Phenolic Content), reducing power, free radical scavenging assay and ferric thiocyanate method. Antibacterial activity of the methanolic extract was analyzed by an agar well diffusion assay confirming the presence of active metabolites of various functional groups by FT-IR, thereby warranting a ‘combinatorial approach’ for applicative pharmacological settings

Assessment of antibacterial efficacy of the methanolic extract of Bacillus vietnamensis PBChS1 isolated from marine sediments of Chidiyatapu coast, South Andaman

Marine bacteria are of extensive significance as new ‘budding springs’ of a vast number of organic active artefacts. Till now, only a fraction of microorganisms have been scrutinized for bioactive metabolites, yet a colossal sum of these metabolites with unique structural drafts remains untouched and unexploited. In this respect, the species of Bacillus vietnamensis was isolated from the marine sediments of Chidiyatapu coast, South Andaman and characterized by both phenotypic and genotypic methods. The anti-oxidative activities of the methanolic extract were determined by the estimation of TPC (Total Phenolic Content), reducing power, free radical scavenging assay and ferric thiocyanate method. Antibacterial activity of the methanolic extract was analyzed by an agar well diffusion assay confirming the presence of active metabolites of various functional groups by FT-IR, thereby warranting a ‘combinatorial approach’ for applicative pharmacological settings

Pathogen-induced activation of disease-suppressive functions in the endophytic root microbiome

Microorganisms living inside plants can promote plant growth and health, but their genomic and functional diversity remain largely elusive. Here, metagenomics and network inference show that fungal infection of plant roots enriched for Chitinophagaceae and Flavobacteriaceae in the root endosphere and for chitinase genes and various unknown biosynthetic gene clusters encoding the production of nonribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs). After strain-level genome reconstruction, a consortium of Chitinophaga and Flavobacterium was designed that consistently suppressed fungal root disease. Site-directed mutagenesis then revealed that a previously unidentified NRPS-PKS gene cluster from Flavobacterium was essential for disease suppression by the endophytic consortium. Our results highlight that endophytic root microbiomes harbor a wealth of as yet unknown functional traits that, in concert, can protect the plant inside out.Microbial Biotechnolog

Guide-free Cas9 from pathogenic Campylobacter jejuni bacteria causes severe damage to DNA

CRISPR-Cas9 systems are enriched in human pathogenic bacteria and have been linked to cytotoxicity by an unknown mechanism. Here, we show that upon infection of human cells, Campylobacter jejuni secretes its Cas9 (CjeCas9) nuclease into their cytoplasm. Next, a native nuclear localization signal enables CjeCas9 nuclear entry, where it catalyzes metal-dependent nonspecific DNA cleavage leading to cell death. Compared to CjeCas9, native Cas9 of Streptococcus pyogenes (SpyCas9) is more suitable for guide-dependent editing. However, in human cells, native SpyCas9 may still cause some DNA damage, most likely because of its ssDNA cleavage activity. This side effect can be completely prevented by saturation of SpyCas9 with an appropriate guide RNA, which is only partially effective for CjeCas9. We conclude that CjeCas9 plays an active role in attacking human cells rather than in viral defense. Moreover, these unique catalytic features may therefore make CjeCas9 less suitable for genome editing applications