Heavy metal contamination along different tidal zones of a tropical Bay of Bengal coastal environment influenced by various anthropogenic activities.

The spatiotemporal variations of five heavy metals (Cd, Cu, Cr, Pb, and Zn) in the beach sediments along the Tamil Nadu coast sourced from various anthropogenic activities were assessed using atomic absorption spectrophotometry (AAS). Various pollution monitoring indices were computed to clearly understand the metal pollution status along the Tamil Nadu coastline. The metal concentrations in sediments were typically higher in the summer season than in the monsoon season. In the monsoon season, metal concentration followed a decreasing order of Zn > Cr > Cu > Pb > Cd, and in the summer season, the order was Cr > Zn > Cu > Pb > Cd. During the monsoon season, freshwater runoff from the rainfall dilutes the sediments and their trace element load. However, due to a lack of freshwater influx during the summer season, the heavy metals in the sediments get concentrated and showed elevated levels. Geo-accumulation index, ecological risk index, pollution load index, and contamination degree clearly depict that Cd and Pb have higher accumulation and pose greater hazard when compared with other metals. The rivers flowing in the region also transport the heavy metals from the mainland to the estuaries and coastal environments. Metal levels along the Tamil Nadu coast are influenced by various anthropogenic activities persistent along the coastline. Some of the activities that cause metal contamination are mining, milling, electroplating, furnishing, pharmaceutical industries, fishing, harbor activities, urban runoff, and agricultural runoff, which release a variety of toxic metals into the coastal environment.

Enhanced anti-biofilm and biocompatibility of Zn and Mg substituted ß-tricalcium phosphate/functionalized multiwalled carbon nanotube composites towards A. baumannii and Methicillin-Resistant Staphylococcus aureus, and MG-63 cells.

In this work, Zn and Mg substituted ß-tricalcium phosphate/functionalized multiwalled carbon nanotube (f-MWCNT) nanocomposites were prepared by the co-precipitation method. The structural, vibrational, morphological and biological properties of the prepared nanocomposites were studied. The structural study revealed that the increase of Zn concentration shifts the ß-tricalcium phosphate planes towards higher angle. Morphological analysis confirmed the formation of hexagonal-shaped particles after substitution of Zn. The particle size of the nanoparticles decreased with the increase of Zn concentration. XPS analysis clearly showed the presence of Zn, Mg, P, Ca, O and C. The Zn (5%) rich nanocomposites have better antibiofilm activity compared to 2% of zinc substituted composite. Also, it has been proven that the prepared nanocomposites have the ability to enhance the bioactivity of commercial antibiotics by means of a decrease in drug resistance. Finally, this study acted as a pioneer to improve drug efficiency and reduced the biofilm formation of certain medically important bacteria. The in-vitro cell viability and anti-biofilm results of zinc (5%) rich nanocomposite confirmed that prepared nanocomposite has biocompatible and enhanced anti-biofilm property, which will be beneficial candidate for biomedical applications.

Avian feathers as a biomonitoring tool to assess heavy metal pollution in a wildlife and bird sanctuary from a tropical coastal ecosystem.

In this study, we have assessed the concentrations of four heavy metals (Cu, Zn, Cd, and Pb) in the feathers of 11 species of birds from the Point Calimere Wildlife and Bird Sanctuary, a protected environment. Concentrations of copper and zinc were detected in all the bird species, cadmium was observed only in two bird species, and lead was below the detection limits for all birds. The order of concentration of metals in the feathers is Zn > Cu > Cd > Pb. Using the multivariate statistical analysis, principal component analysis (PCA), the metal origins were traced to natural, dietary, and manmade sources. In addition, sediment samples were also collected from the sanctuary, to assess the bioaccumulation factor (BAF). The BAF values follow the order Cd < Cu < Zn < Pb. In comparison with worldwide heavy metal reports in bird feathers, lower concentrations of metals are observed in our study area. The tropical marine ecosystem at Point Calimere Wildlife and Bird Sanctuary can be considered as pristine regarding heavy metal pollution. Continuous monitoring of the ecosystem is crucial to sustain the pristine nature of the sanctuary and to attract many more birds.

Health risk assessment and bioaccumulation of metals in brown and red seaweeds collected from a tropical marine biosphere reserve.

In the present study, we have assessed the degree of contamination of heavy metals (Cd, Cu, Pb, and Zn) in ten species of red and brown seaweeds, the seasonal variations in the concentration of metals, and the health risk due to the seaweeds. Overall metal concentrations for red and brown seaweeds followed the order Pb > Zn > Cu > Cd and Pb > Cu > Zn > Cd, respectively. Cd and Pb levels were found to be elevated in both the red and brown seaweeds. Multivariate statistical analysis revealed that the sources of Cd and Pb are mainly anthropogenic. Despite the high concentrations of the non-essential metals (Cd and Pb) in the seaweeds, the health risk assessment revealed that they have a lower hazard index. Hence, consumption of edible red and brown seaweeds from the Tuticorin coast may not pose health hazards in humans for the time being.

Callophycin A loaded chitosan and spicules based nanocomposites as an alternative strategy to overcome vaginal candidiasis.

The present study aimed to understand the killing effects of seaweed derived metabolite Callophycin A (Cal A). In vitro studies confirmed that the beneficial effects of Cal A on the viability of C. albicans. To enhance the biological activity, we used to demonstrated that chitosan and spicules as a drug carrier. The Callophycin A loading was confirmed by spectral variation of FT-IR and morphological variation by SEM. Moreover, around 65% and 38% of Cal A was successfully loaded in chitosan and spicules respectively. Further, VVC induced animal model experiments confirmed that the candidicidal activity of 1% clotrimazole, Cal A, Cal@Chi and Cal@Spi. After 6 days of treatment Cal@Chi produces a significant reduction in the fungal burden of vaginal lavage. The histo-morphological alterations also evidenced that the protective role of Cal@Chi in VVC model. The present investigations are known to be the first and foremost study to discriminate the potentiality of Cal A composites. Cal A loaded chitosan nanoparticles could be used as an alternative strategy for the development of the novel marine natural product based topical applications.

Optimization, compositional analysis, and characterization of exopolysaccharides produced by multi-metal resistant Bacillus cereus KMS3-1.

The isolation, screening, and identification of multi-metal resistant (Cd, Cu, Pb, and Zn) bacteria from polluted coastal sediment samples were performed. In this study, the isolates S2-2 and S3-2 had higher multi-metal resistance and were identified as Pseudomonas pachastrellae KMS2-2 and Bacillus cereus KMS3-1, respectively. One-variable-at-a time approach suggested that optimum conditions for exopolysaccharides (EPS) production were pH 7.0, incubation time 120 h, 5 g/L sucrose, and 10 g/L yeast extract. Further, optimization by central composite design revealed that the optimum concentrations of sucrose and yeast extract for higher EPS production (8.9 g/L) were 5 g/L, and 30 g/L, respectively. Heteropolysaccharide nature of EPS determined by FTIR, TLC, and HPLC analysis, consist of mannose, rhamnose, glucose, and xylose. In addition, EPS showed strong emulsifying and flocculation activity. Results suggested the potential EPS-producing multi-metal resistant Bacillus cereus KMS3-1 could be used in biotechnological and industrial application, especially metal removal.

Cardiovascular dysfunction and oxidative stress following human contamination by fluoride along with environmental xenobiotics (Cd & Pb) in the phosphate treatment area of Togo, West Africa.

In Togo, the phosphate ore mill discharges waste containing xenobiotics like cadmium, lead and fluoride. If the role of heavy metals in the appearance of pathologies is known, the role of fluoride remains to be studied alongside xenobiotics. This study tested the hypothesis that the toxicity of fluoride contributes, along with heavy metals, to physiological dysfunction. In this process, we have studied the variation in the parameters of cardiovascular functioning, depending on the level of human contamination by fluoride and xenobiotics. The concentration of Cd and Pb in blood samples were determined by AAS and fluoride by titanium-chloride method. Lipid peroxidation, the total antioxidant potential of collected blood samples and the parameters of cardiovascular dysfunction were also measured. Cd, Pb and F contents and lipid peroxidation were found to be significantly elevated in polluted areas than control zone as well as total cholesterol, LDL and triglyceride. HDL and antioxidant potential of blood decreased in the polluted areas. Correlation tests showed that fluoride levels are related to variations in the bio-indicators of high blood pressure and oxidative stress (R varied from 0.354 to 0.907). Togo phosphate treatment leads to human contamination with fluoride, along with Cd and Pb, increasing the risk of cardiovascular dysfunction and oxidative stress.

Evaluation of antidiabetic activity of bud and flower of Avaram Senna (Cassia auriculata L.) In high fat diet and streptozotocin induced diabetic rats.

Type 2 Diabetes Mellitus (T2DM) is very common metabolic disorder affecting people of all age groups. The change in life style and environmental factors are the considerable factors which are involved in the development of the disorder. The different parts of medicinal plants vary in their composition of bioactive compounds. There are reports on antidiabetic activity of C. auriculata L. flower and leaves. Traditionally bud of C. auriculata L. is used to treat diabetes rather than flower. This study aims to explore the antidiabetic efficiency of bud and flower and to identify the differential composition of phycompounds present in bud and flower parts of C. auriculata L. The compounds present in the bud and flower parts were identified using LC-ESI/MS analysis. Antidiabetic activity of C. auriculata L. bud and flower parts was studied in high fat diet (HFD) and streptozotocin (STZ) induced diabetic rats. During which parameters such as feed intake, water intake, and body weight were monitored. After 21 days of the study, blood parameters like insulin, glucose, lipid profile, hepatic function test, renal function test and oxidative stress markers were analysed. Real time PCR was done to monitor the expression of IRS2 and GRIA2 genes. The LC-ESI/MS analysis showed the presence of various phenolics and flavonoid compounds specific to bud and flower parts. The antidiabetic activity results showed that the animal treated with C. auriculata L. bud ethanol extract (CABE500) could better reverse and control the progression of the disease compared to the flower ethanol extract. The gene expression studies revealed that regulation of IRS2 gene occurred in bud but not in flower extract treated animal livers and no differential expression of GRIA2 gene in all the experimental groups. C. auriculata L. bud extract can potentially better control the diabetes compared to the flower extract.

Structural characterization and anticancer activity (MCF7 and MDA-MB-231) of polysaccharides fractionated from brown seaweed Sargassum wightii.

The purpose of this study was to investigate the anticancer activity of polysaccharides from brown seaweed Sargassum wightii (SWP) on human breast cancer cells. Initially, two polysaccharide fractions (SWP1 and SWP2) were isolated and purified from the crude polysaccharides using DEAE-52 cellulose and Sephadex G-100 column chromatography. As a result, SWP1 was obtained with the yield of 21.48% was characterized using chemical analysis, GC-MS, 1H NMR and 13C NMR. The chemical composition of the extracted polysaccharide contains a neutral polysaccharide with a high total sugar content and low protein, phenol and flavonoid content. GC-MS analysis revealed the presence of galactofuranose and arabinose and NMR spectra shows the presence of ß-galactose signals. Anticancer activity shows that the polysaccharides significantly reduce the proliferation of breast cancer cells (MCF7 and MDA-MB-231) in a dose-dependent manner. Further, polysaccharides induced the apoptosis in the breast cancer cells by increasing ROS generation, cleaving mitochondrial membrane and nuclei damage. Finally, polysaccharides increased the activity of caspase 3/9, thus leads to apoptosis of breast cancer. Together, polysaccharides from S. wightii could be a new source of natural anticancer agent against breast cancer with potential value in the manufacturing supplements and drugs.

Development of thermostable amylase enzyme from Bacillus cereus for potential antibiofilm activity.

The marine bacterial strain Bacillus cereus was used to produce amylase enzyme and has excellent alkali-stable and thermostable enzymatic activity. The combined effects of pH, temperature and incubation time on amylase activity were studied using response surface methodology. The amylase enzyme activity was also determined in the presence of various metal ions, chelating agents, detergents and the results showed that the maximum enzyme activity was observed in the presence of calcium chloride (96.1%), EDTA (63.4%) and surf excel (90.6%). The amylase enzyme exhibited excellent antibiofilm activity against marine derived biofilm forming bacteria Pseudomonas aeruginosa and Staphylococcus aureus in microtiter plate assay and congo red assay. Light and confocal laser scanning microscopic (CLSM) analysis were also used to confirm the potential biofilm activity of amylase enzyme. The CLSM analysis showed the inhibition of complete biofilm formation on amylase enzyme treated glass surface. Further in vivo toxicity analysis of amylase enzyme was determined against marine organisms Dioithona rigida and Artemia salina. The results showed that there is no morphological changes were observed due to the minimal toxicity of amylase enzyme. Overall these findings suggested that marine bacterial derived amylase enzyme could be developed as potential antibiofilm agent.

First report on distribution of heavy metals and proximate analysis in marine edible puffer fishes collected from Gulf of Mannar Marine Biosphere Reserve, South India.

In the present study, the heavy metal concentration in different organs (skin, tissue, liver, kidney, gill, intestine, and ovary) and muscle proximate composition were studied in marine edible puffer fishes Takifugu oblongus, Lagocephalus guentheri, Arothron hispidus, Chelonodon patoca and Arothron immaculatus collected from Mandapam fish landing centre, South east coast of India. Heavy metals (Cd, Cu, Pb & Zn) were analyzed in different organs for the above mentioned species. The heavy metals concentration ranges in fish organs of all the five species were Cu (0.42 -6.31 mg/kg), Cd (0.01-0.79 mg/kg), Pb (5.80-19.87 mg/kg), and Zn (6.75-65.08 mg/kg). Zn was detected higher in all the samples followed by Pb, Cu and Cd. The proximate composition was determined in edible muscle tissues of all the five species. The highest and lowest protein contents were observed in T. oblongus (20.6 ± 0.6%) and C. patoca (17.9 ± 0.3%). In the present study, heavy metal concentrations were found very high in all the internal organs when compared to muscle tissues. Further, this is the first report on distribution of heavy metals and proximate compositions of commercialized important edible puffer fishes from Mandapam coast of Gulf of Mannar, Southeast coast of India.

Marine steroid derived from Acropora formosa enhances mitochondrial-mediated apoptosis in non-small cell lung cancer cells.

p53 pathway has been revealed to mediate cellular stress responses and trigger DNA repair, cell cycle arrest, senescence, and apoptosis. We isolated 2-ethoxycarbonyl-2-ß-hydroxy-A-nor-cholest-5-ene-4one (ECHC) from butanol extracts of scleractinian coral Acropora formosa and reported its potential antioxidant and antimicrobial activity as well as less toxicity against zebrafish Danio rerio. In the present study, we intend to explore p53-mediated apoptosis pathway enhanced by ECHC in A549 human non-small cell lung cancer cell lines. This report shows that ECHC increases ROS generation and sensitizes mitochondrial membrane that leads to the release of cytochrome C (Cyto C) into cytosol. Further, ECHC decreases the expression of antiapoptotic genes such as TNF-α, IL-8, Bcl2, MMP2, and MMP9 which are actively involved in cancer cell proliferation, invasion, and metastasis etc. It also increases the expression of apoptotic genes Cyto C, Bax, and p21, which are responsible for cell cycle arrest and cell death. The tumor suppressor p53 was also observed to be upregulated during ECHC treatment in untransformed cells and was more likely to result in cell cycle arrest, senescence, and apoptosis. Finally, ECHC also down regulates the expression of caspase-9 and caspase-3 which are the death stage of intrinsic apoptosis. Our findings suggested that ECHC enhances ROS generation and mitochondrial sensitization determines the threshold for irreversible p53-mediated intrinsic apoptosis pathway.