Seasonal Assessment of Heavy Metal Pollution in Tropical Mangrove Sediments (Goa, India)

Mangrove swamps along the Mandovi estuary, Goa are exposed to an influx of metal effluents from the ferromanganese mining activities.  The present study was carried out to assess the seasonal concentrations of metals in the sediments of Divar, an anthropogenically-influenced mangrove swamp in the Mandovi estuary, and compared to Tuvem along the Chapora River, a relatively pristine mangrove site. In both the sites, the average heavy metal concentration in sediments decreased in the order: Fe > Mn > Zn > Cu > Co > Pb > Cr and showed a marked seasonal variability (p< 0.001; df=2).  However, the Pollution Load Index (PLI) for Divar sediments was far greater (1.65-2.19) than that of Tuvem (0.91-1.3) reflecting the intensity of anthropogenic inputs into the ecosystem. Further, Muller geochemical index values for Divar sediments indicated that during pre and post-monsoon season, the sediments were moderately contaminated with Fe whereas at Tuvem, the sediments were below contamination levels. The comparison with Screening Quick Reference Table (SQuiRT) also revealed the poor sediment quality for Divar. The transport of ferromanganese ore along the Mandovi River could be a major source of the entry of heavy metals in this riverine system. The Effect Range- Low (ER-L) values for these elements exceeded the reference values suggesting a potential eco-toxicological risk to the benthic organisms and a possible transfer to higher trophic levels

Bacteria from Salt Pans: A Potential Resource of Antibacterial Metabolites

Marine salt pans are important ecological niches which inhabit halobacteria. These bacteria tolerate and thrive in salt concentrations ranging from 0.5 to more than 5 M in which only very few other organisms are able to survive. Bacteria from marine salt pans of varying salinities of 220 to 395 psu were isolated during the peak salt harvesting season and screened to evaluate their antibiotic producing potential. In this report, a total of 119 bacteria were screened on 12 different solid media supplemented with either natural salt or sea water or distilled water to check their substrate utilization and salinity requirement. Based on their morphological variations, 94 isolates were further screened for their antagonistic properties, against 20 different clinical pathogens. Thirty one isolates were found to produce antibacterial compounds of which, 21 showed bactericidal action and one was bacteriostatic while 9 isolates exhibited both bacteriostatic and bactericidal activity. Eleven isolates were broad spectrum antibiotic producers. This study provides information regarding the applied value of potential halotolerant and halophilic isolates as pharmaceutically important microorganisms

Biotechnological significance of Actinobacterial research in India.

Actinobacteria are of special biotechnological interest since they are known to produce chemically diverse compounds with a wide range of biological activity. This distinct clade of Gram-positve bacteria include some of the key antibiotic producers and are also sources of several bioactive compounds, established commercially. The class Actinobacteria holds some of the resilient species, capable of growing in extreme, hostile and polluted environments. Their adaptation has been the outcome of several chemical entities which are answers to a number of medicinal and industrial questions of today. In India, actinobacterial research in both marine and terrestrial ecosystems has prospered significantly in past few decades. This valuable class contains large number of genera and demands more attention for exploration. Though substantial work in this field has been carried out, the diversity from the extreme environments in the Indian Peninsula remain unexplored. Marine actinobacterial research has been restricted to the coastal ecosystem while the deep sea oceanic floors remain untapped. Substantial bioprospecting of actinobacteria for bioactive molecules, has not been explored in extremophilic environments in India and the molecular mechanisms for the production of various bioactive compounds are yet to be reported. The present review enlists the prolific metabolites from culturable actinobacteria and attempts have been made to focus on the&nbsp; potentially feasible aspects of actinobacterial research in this field

Bacterial diversity and community structure of salt pans from Goa, India

In Goa, salt production from the local salt pans is an age-old practice. These salt pans harbor a rich diversity of halophilic microbes with immense biotechnological applications, as they tolerate extremely harsh conditions. Detecting the existence of these microbes by a metabarcoding approach could be a primary step to harness their potential. Three salt pans viz. Agarwado, Curca, and Nerul adjoining prominent estuaries of Goa were selected based on their unique geographical locations. The sediments of these salt pans were examined for their bacterial community and function by 16S rRNA amplicon-sequencing. These salt pans were hypersaline (400–450 PSU) and alkaline (pH 7.6–8.25), with 0.036–0.081 mg/L nitrite, 0.0031–0.016 mg/L nitrate, 6.66–15.81 mg/L sulfate, and 20.8–25.6 mg/L sulfide. The relative abundance revealed that the Pseudomonadota was dominant in salt pans of Nerul (13.9%), Curca (19.6%), and Agarwado (32.4%). The predominant genera in Nerul, Curca, and Agarwado salt pan sediments were Rhodopirellula (1.12%), Sulfurivermis (1.28%), and Psychrobacter (25.5%) respectively. The highest alpha diversity (Shannon-diversity Index) was observed in the Nerul salt pan (4.8) followed by Curca (4.3) and Agarwado (2.03). Beta diversity indicated the highest dissimilarity between Agarwado and the other two salt pans (0.73) viz. Nerul and Curca and the lowest dissimilarity was observed between Nerul and Curca salt pans (0.48). Additionally, in the Agarwado salt pan, 125 unique genera were detected, while in Nerul 119, and in Curca 28 distinct genera were noted. The presence of these exclusive microorganisms in a specific salt pan and its absence in the others indicate that the adjacent estuaries play a critical role in determining salt pan bacterial diversity. Further, the functional prediction of bacterial communities indicated the predominance of stress adaptation genes involved in osmotic balance, membrane modification, and DNA repair mechanisms. This is the first study to report the bacterial community structure and its functional genes in these three salt pans using Next-Generation Sequencing. The data generated could be used as a reference by other researchers across the world for bioprospecting these organisms for novel compounds having biotechnological and biomedical potential

PHARMACEUTICAL POTENTIALS OF BACTERIA FROM SALTPANS OF GOA, INDIA

ABSTRACT: Solar salt pans consist of a series of inter linked pans where gradients of salinity occur due to evaporation of seawater. Salinity in these ponds reaches as high as 400 psu during the peak salt-producing season and as low as 5 psu during the monsoons. Salt pans are extreme environments which inhabit organisms that thrive high salinities, temperatures and withstand severe solar radiations. Such organisms are capable of producing interesting metabolites which may benefit mankind. Salt pan water, salt and sediment samples were collected from nine saltpans from North and South Goa to isolate bacteria. The bacterial extracts have been screened for various biological activities to ascertain their biomedical importance. A total of 63 out of 1178 cultures were found to be active showing antioxidant, anti gastric ulcer, antifungal, memory enhancing activity and activity against neurological disorders, anticancer, amylase, amylase inhibitory, protease and protease inhibitory activity. This study highlights the biomedical potential of bacteria from salt pans and encourages further exploration of such bacteria for therapeutic activities

Insights on metal-microbe interactions in Bacillus sp. and Chromohalobacter sp. from a solar saltern

Metal tolerant bacterial strains viz Bacillus cereus (RS-1), Bacillus sp. (RS-2) and Chromohalobacter beijerinckii (RS-3) were isolated from the surface sediments of a solar saltern in Ribandar Goa, situated in the vicinity of the Mandovi estuary influenced by mining activities. RS-1 that showed optimal growth at 20 psu salinity was tolerant to 10 mM Co2+ while hypersaline isolates RS-2 (100 psu) and RS-3 (200 psu) were tolerant to Ni2+ and Mn2+ at 1 mM and 10 mM respectively. Experimental studies revealed that growth was stimulated at low concentrations of metal amendments for all the isolates. Growth of RS-1 was stimulated by ~450% on addition of 100 &micro;M Co2+ whereas for RS-2 and RS-3 it was at 100 &micro;M Ni2+ (70%) and 5 mM Mn2+ (450%). The stimulation in growth was coupled to a dip in respiration rates for the isolates RS-1 and RS-3 when compared to metal unamended controls. The respiration rates for RS-1 and RS-3 during peak growth in the presence of metal were 17.0 and 27.5 compared to the controls which were 24.7 and 473.4 pg formazan cell-1 day-1 respectively. Presence of Ni2+ stimulated the respiration rate (26%) in RS-2 when compared to the control (417.4 pg formazan cell-1 day-1). Co2+ and Mn2+ had a significant negative impact on the utilization of carbohydrates and carboxylic acids in RS-1 and RS-3 respectively. Ni2+ had a stimulatory effect on the utilization of BIOLOG GP2 substrates by RS-2. The phenotypic expressions observed above were correlated with the changes in whole cell protein profiles in the presence and absence of added metal. Addition of Co2+ to RS-1 resulted in a significant up-regulation of 57 kDa fraction while there was a conspicuous down-regulation of 29 kDa protein. The major protein fraction up-regulated in RS-2 in the presence of Ni2+ was a 59 kDa protein while most of the fractions were down-regulated. In RS-3, the addition of Mn2+ at 10, 100 and 1000 &micro;M up-regulated a 50 kDa protein while the 53 kDa fraction was down-regulated. This study relates the metal induced regulation of proteins to phenotypic variations encountered in growth and substrate utilization.&nbsp;&nbsp

A halophilic Chromohalobacter species from estuarine coastal waters as a detoxifier of manganese, as well as a novel bio-catalyst for synthesis of n-butyl acetate

Anthropogenic pollution due to ferro-manganese ore transport by barges through the Mandovi estuary in Goa, India is a major environmental concern. In this study a manganese (Mn) tolerant, moderately halophilic Chromohalobacter sp. belonging to the family Halomonadaceae was isolated from the sediments of a solar saltern adjacent to this Mandovi estuary. Using techniques of Atomic absorption spectroscopy, Scanning electron microscopy-Energy dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy and Atomic Force Microscopy, the Chromohalobacter sp. was explored for its ability to tolerate and immobilize Mn in amended and unamended media with 20% natural salt concentration (w/v). In aqueous media supplemented with 0.1 mM Mn, the Chromohalobacter sp. was capable of sequestering up to 76% Mn with an average immobilization rate of 8 mg Mn /g /day. Growth rate kinetic analysis using Gompertz mathematical functions was found to model the experimental data well. The model inferred that the maximum growth rate of Chromohalobacter sp. was at 10% natural salt concentration (w/v). The Chromohalobacter sp. was further found to be multimetal tolerant showing high tolerance to Iron (Fe), Nickel (Ni) and Cobalt (Co), (each at 4 mM), and tolerated Manganese (Mn) up to 6 mM. Morphologically, the Chromohalobacter sp. was a non-spore forming, Gram negative motile rod (0.726 μ× 1.33 μ). The adaptative mechanism of Chromohalobacter sp. to elevated Mn concentrations (1 mM) resulted in the reduction of its cell size to 0.339 μ× 0.997 μ and the synthesis of an extracellular slime, immobilizing Mn from the liquid phase forming Manganese oxide, as confirmed by Scanning Electron Microscopy. The expression of Mnx genes for manganese oxidation further substantiated the finding. This bacterial synthesized manganese oxide also displayed catalytic activity (∼50% conversion) for the esterification of butan-1-ol with CH3COOH to yield n-butyl acetate. This Chromohalobacter sp. being indigenous to marine salterns, has adapted to high concentrations of heavy metals and high salinities and can withstand this extremely stressed environment, and thus holds a tremendous potential as an environmentally friendly “green bioremediator” of Mn from euryhaline environments. The study also adds to the limited knowledge about metal-microbe interactions in extreme environments. Further, since Chromohalobacter sp. exhibits commendable catalytic activity for the synthesis of n-butyl acetate, it would have several potential industrial applications

Deciphering shared attributes of plant long non-coding RNAs through a comparative computational approach

Abstract Over the past decade, long non-coding RNA (lncRNA), which lacks protein-coding potential, has emerged as an essential regulator of the genome. The present study examined 13,599 lncRNAs in Arabidopsis thaliana, 11,565 in Oryza sativa, and 32,397 in Zea mays for their characteristic features and explored the associated genomic and epigenomic features. We found lncRNAs were distributed throughout the chromosomes and the Helitron family of transposable elements (TEs) enriched, while the terminal inverted repeat depleted in lncRNA transcribing regions. Our analyses determined that lncRNA transcribing regions show rare or weak signals for most epigenetic marks except for H3K9me2 and cytosine methylation in all three plant species. LncRNAs showed preferential localization in the nucleus and cytoplasm; however, the distribution ratio in the cytoplasm and nucleus varies among the studied plant species. We identified several conserved endogenous target mimic sites in the lncRNAs among the studied plants. We found 233, 301, and 273 unique miRNAs, potentially targeting the lncRNAs of A. thaliana, O. sativa, and Z. mays, respectively. Our study has revealed that miRNAs, which interact with lncRNAs, target genes that are involved in a diverse array of biological and molecular processes. The miRNA-targeted lncRNAs displayed a strong affinity for several transcription factors, including ERF and BBR-BPC, mutually present in all three plants, advocating their conserved functions. Overall, the present study showed that plant lncRNAs exhibit conserved genomic and epigenomic characteristics and potentially govern the growth and development of plants

Data_Sheet_1_A halophilic Chromohalobacter species from estuarine coastal waters as a detoxifier of manganese, as well as a novel bio-catalyst for synthesis of n-butyl acetate.pdf

Anthropogenic pollution due to ferro-manganese ore transport by barges through the Mandovi estuary in Goa, India is a major environmental concern. In this study a manganese (Mn) tolerant, moderately halophilic Chromohalobacter sp. belonging to the family Halomonadaceae was isolated from the sediments of a solar saltern adjacent to this Mandovi estuary. Using techniques of Atomic absorption spectroscopy, Scanning electron microscopy-Energy dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy and Atomic Force Microscopy, the Chromohalobacter sp. was explored for its ability to tolerate and immobilize Mn in amended and unamended media with 20% natural salt concentration (w/v). In aqueous media supplemented with 0.1 mM Mn, the Chromohalobacter sp. was capable of sequestering up to 76% Mn with an average immobilization rate of 8 mg Mn /g /day. Growth rate kinetic analysis using Gompertz mathematical functions was found to model the experimental data well. The model inferred that the maximum growth rate of Chromohalobacter sp. was at 10% natural salt concentration (w/v). The Chromohalobacter sp. was further found to be multimetal tolerant showing high tolerance to Iron (Fe), Nickel (Ni) and Cobalt (Co), (each at 4 mM), and tolerated Manganese (Mn) up to 6 mM. Morphologically, the Chromohalobacter sp. was a non-spore forming, Gram negative motile rod (0.726 μ× 1.33 μ). The adaptative mechanism of Chromohalobacter sp. to elevated Mn concentrations (1 mM) resulted in the reduction of its cell size to 0.339 μ× 0.997 μ and the synthesis of an extracellular slime, immobilizing Mn from the liquid phase forming Manganese oxide, as confirmed by Scanning Electron Microscopy. The expression of Mnx genes for manganese oxidation further substantiated the finding. This bacterial synthesized manganese oxide also displayed catalytic activity (∼50% conversion) for the esterification of butan-1-ol with CH3COOH to yield n-butyl acetate. This Chromohalobacter sp. being indigenous to marine salterns, has adapted to high concentrations of heavy metals and high salinities and can withstand this extremely stressed environment, and thus holds a tremendous potential as an environmentally friendly “green bioremediator” of Mn from euryhaline environments. The study also adds to the limited knowledge about metal-microbe interactions in extreme environments. Further, since Chromohalobacter sp. exhibits commendable catalytic activity for the synthesis of n-butyl acetate, it would have several potential industrial applications.</p