Arunachalam Palavesam

Antifouling and toxic properties of the bioactive metabolites from the seagrasses Syringodium isoetifolium and Cymodocea serrulata

The present study documents the antifouling and toxic properties of seagrasses Syringodium isoetifolium and Cymodocea serrulata. For that, the seagrasses S. isoetifolium and C. serrulata were extracted individually using organic solvents viz. dichloromethane, acetone and methanol. Amongst the extracts, the maximum antimicrofouling and antimacrofouling activities were exhibited by methanol extracts of both the seagrasses. The Minimal Inhibitory Concentration (MIC) of methanolic extracts of seagrasses was ranged from 1.0 to 10µg/ml against test biofilm bacteria and microalgal strains. Similarly, 100% fouling inhibition of limpet Patella vulgata was found at 6.0mg/ml of methanolic extracts of seagrasses. The mussel Perna indica showed 50% of byssal production and attachment inhibition at 21.51±2.03, 17.82±1.07µg/ml and the anticrustaecean activity for 50% mortality of Artemia salina was recorded at 732.14±9.21 and 394.16±5.16µg/ml respectively for methanolic extracts of S. isoetifolium and C. serrulata. The minimal inhibitory and higher lethal concentrations of active methanol extracts shows it׳s less toxic nature. Based on the prolific results, methanol extracts of S. isoetifolium and C. serrulata were subjected to purification using silica gel column and thin layer chromatography. Then the active compounds of the bioassay guided fractions were partially characterized using gas chromatography coupled with mass spectroscopy (GC-MS) and keyed out that fatty acids (C16 to C24) were the major components which responsible for the antifouling properties of the candidate seagrasses.

Optimization of bacteriocin production by Lactobacillus sp. MSU3IR against shrimp bacterial pathogens

BackgroundAquaculture is one amongst the growing and major food producing sectors. Shrimp culture is one of the subsectors of aquaculture that attracts more attention because of the economic interest. However, the shrimp culture systems have been facing severe consequences and economical losses due to disease outbreaks. Risk of disease outbreak can be combated with the application of probiotics. For economically viable production of such probiotic products, the present study provides information on the optimization and partial purification of bacteriocin produced by a goat milk isolate Lactobacillus sp. MSU3IR against the shrimp bacterial pathogens.ResultsBacteriocin production was estimated as a measure of bactericidal activity (arbitrary Unit/ml) over the test strains. The optimum culture conditions and media components for maximum bacteriocin production by Lactobacillus sp. MSU3IR were: pH: 5.0, temperature: 30°C, carbon source: lactose; nitrogen source: ammonium acetate; NaCl: 3.0% and surfactant: Tween 80. MRS medium was found to extend better bacteriocin production than other tested media. Upon partial purification of bacteriocin, the SDS-PAGE analysis had manifested the presence of two peptide bands with the molecular weight of 39.26 and 6.38 kDa, respectively.ConclusionThe present results provide baseline trend for the statistical optimization, scale up process and efficient production of bacteriocin by the candidate bacterial strain Lactobacillus sp. MSU3IR which could be used to replace the usage of conventional chemotherapeutics in shrimp culture systems.

Antifouling activity of the methanolic extract of Syringodium isoetifolium, and its toxicity relative to tributyltin on the ovarian development of brown mussel Perna indica

The present study evaluated reproductive toxicity and antifouling activity of methanolic extract of seagrass Syringodium isoetifolium (25 μg/ml) relative to the conventional antifoulant, tributyltin (TBT; 100 ng/l) on the ovarian development of the brown mussel Perna indica. Gonado Somatic Index (GSI) and Digestive Gland Index (DGI) of TBT exposed mussels decreased in comparison with mussels exposed to S. isoetifolium extract. Interestingly, mussels treated with S. isoetifolium showed normal cellular architecture in gills, digestive gland, muscle and ovary. However, TBT increased interfilamental space and fusion of the filaments in gills, disruption in the digestive tubules and reduction in basement membrane thickness. Besides in adductor muscle, TBT induced muscle degeneration, and necrotic muscle layer. In ovary, TBT inflicted the fusion of developing oocytes. TBT had significantly retarded the ovarian development and substantially affected the biochemical constituents leading to an impairment of oogenesis as against the null effects noticed from the S. isoetifolium extract treated mussels. On the ground of eco-friendly properties, the seagrass S. isoetifolium could be used as a source for the production of green antifoulant.

Dietary effect of Sargassum wightii fucoidan to enhance growth, prophenoloxidase gene expression of Penaeus monodon and immune resistance to Vibrio parahaemolyticus.

The polysaccharide fucoidan from brown seaweed Sargassum wightii was extracted and it was incorporated with pellet diets at three concentrations (0.1, 0.2 & 0.3%). The fucoidan incorporated diets were fed to shrimp Penaeus monodon for 60 days and the growth performance was assessed. The weight gain and SGR of control group was 6.83 g and 9.72%, respectively, but the weight gain and SGR of various concentrations (0.1-0.3%) of fucoidan incorporated diets fed groups of shrimp was increased from 7.30 to 8.20 g and 9.83 to 10.03%, respectively. After 60 days of feeding experiment, the relative quantification of prophenoloxidase gene of experimental groups over control group was analysed by RT-PCR and it was ranged between 2.13 and 7.95 fold increase within 33.52-34.61 threshold cycles, respectively at 0.1-0.3% concentrations of fucoidan. After 60 days of feeding experiment, the P. monodon were challenged with shrimp pathogen Vibrio parahaemolyticus and the mortality percentage was recorded daily up to 21 days. The reduction in mortality percentage of experimental groups over control group was recorded from 44.56 to 72.79%, respectively in 0.1-0.3% of fucoidan incorporated diets fed groups. During challenge experiment, all the immunological parameters such as THC, prophenoloxidase activity, respiratory burst activity, superoxide dismutase activity, phagocytic activity, bactericidal activity and bacterial clearance ability of experimental groups were significantly (P < 0.05) increased than control group. The V. parahaemolyticus load was enumerated from the infected shrimp at every 10 days intervals during challenge experiment. In control group, the Vibrio load was increased in hepatopancreas and muscle tissues from 10th to 21st days of challenge test. But in the experimental groups, the Vibrio load in both the tissues decreased positively from 10th to 21st days of challenge duration. It is concluded that the S. wightii fucoidan had enhanced the innate immunity and increased resistance to V. parahaemolyticus infection in P. monodon.

Environmentally benign antifouling potentials of triterpene-glycosides from Streptomyces fradiae: a mangrove isolate

In the present study, an attempt has been made to screen and evaluate the antifouling potentials of the actinobacterial strain Streptomyces fradiae RMS-MSU isolated from the manakkudy mangroves of Tamilnadu. Screening results showed that the ethyl acetate extract of S. fradiae RMS-MSU displayed a wide spectrum of antagonistic activity (10 to 21 mm) against marine biofilm bacterial strains with least minimal inhibitory concentrations (MIC) and maximum bactericidal concentrations (MBC). The extract showed promising antimicroalgal activity with MIC values ranging between 100 and 400 μg mL−1. The anti-crustacean activity for 50% mortality (LC50) of Artemia salina was recorded as 273.77 μg mL−1. An EC50 value of 77.03 μg mL−1 for the 50% inhibition of byssus production and attachment of mussel Perna indica was observed. The crude extract of S. fradiae RMS-MSU showed an LC50 value of 718.79 μg mL−1 for 50% mortality of mussel. A therapeutic ratio (LC50/EC50) of 9.33 indicated the nontoxic nature of the extract. The mollusc foot adherence assay using the limpet Patella vulgata showed 6.66% fouling and 92.96% regaining at 7 mg mL−1 after transfer to fresh seawater.

In vitro antioxidant activities of an exopolysaccharide from a salt pan bacterium Halolactibacillus miurensis

Exopolysaccharide (EPS) designated as HMEPS was isolated from Halolactibacillus miurensis and purified through gel filtration chromatography. EPS extracted from the supernatant yielded a 56.1% total carbohydrate content. The ash and moisture content were 12.1% and 1.5% respectively. Galactose and glucose were found as main monosaccharides of the HMEPS through HPLC analysis. FT-IR spectra of the HMEPS revealed its composition with hydroxyl, alkenes, amide and carboxyl as functional groups and aliphatic amine and alkynes at the fingerprint region. In vitro antioxidant activity was investigated against hydroxyl, DPPH, superoxide free radicals and the scavenging activity against all were found to be dose dependent proportionately. HMEPS showed higher reducing ability against superoxide radical and potency in chelating the ferrous ions. 10mg/ml of HMEPS was found equivalent to 2.7units of ascorbic acid through the total antioxidant assay. Phylogenetic relation of H. miurensis SEEN MKU3 (GenBank number KT803852) was plotted with MEGA 5.0.

Antipyretic, wound healing and antimicrobial activity of processed shell of the marine mollusc Cypraea moneta

Article history: Objective: Some of the products derived from marine organisms have been recommended in alternative system of medicine especially Siddha medicine for several treatments. Among the marine molluscs, Cypraea moneta shell has been used as siddha medicine from ancient days. But no systematic study has been done on its efficacy as antipyretic, wound healing and as antimicrobial agent. In the present study, the protective action of processed shell powder of C. moneta was evaluated by us in an animal model for the above treatments. Methods: C. moneta shell powder was prepared by standard method described in Siddha medicine. Then the antipyretic, wound healing as well as antimicrobial effect of the processed powder was tested in Wister albino rats. Results: By the intravenous injection of yeast cell suspension into albino rats, the antipyretic effect of the shell powder given orally was studied by various concentrations of 0, 10, 20 and 30 mg/ml. The body temperature of the albino rat became normal within a short duration (3h). The wound healing effect of the shell powder was very effective. In the thigh region 2 cm wound was made and the different dosages of shell powder (C -Control, SD - Single dose, DD -Double dosage and TD -Triple dose/day) were applied externally as ointment. The scar was produced in eighth day onwards in DD and TD. Antimicrobial activity was studied in three different oppurtunistic human pathogens such as Micrococcus sp., Proteus vulgaris and Salmonella abory in different concentrations (2, 3, 4 and 5% w/v) of C. moneta shell powder extract. Among these, Proteus vulgaris showed the maximum zone of inhibition (15mm size) against 5% w/v concentration, followed by Micrococcus sp. (12mm) and S. abory (10mm) against the same concentration. Conclusions: The present observation suggested that, processed C. moneta shell powder can be used as an alternative medicine, and it has antipyretic, wound healing as well as antimicrobial properties.

Preliminary optimization of solid-state phytase production by moderately halophilic Pseudomonas AP-MSU 2 isolated from fish intestine

The production of extracelluar phytase by Pseudomonas AP-MSU 2 isolated from the estuarine fish Etroplus suretensis was investigated in solid-state fermentation. Screening of agroindustrial substrates revealed that cassava waste meal produced a higher amount of phytase. The most suitable nitrogen source to enhance phytase production was found to be sodium nitrate. Among various carbon sources tested, maximum production of phytase was registered in medium with added fructose. The effect of surfactants indicated that maximum phytase production was observed in medium supplemented with Tween 60. NaH2PO4 and ZnCl were found to be a suitable phosphate and metal ion source, respectively, for maximizing phytase production. The optimum sodium chloride concentration for high phytase production was found to be 3%. The optimum pH and temperature for phytase production were found to be 7 and 30°C, respectively. Statistical optimization using a Plackett-Burman design showed that fructose, sodium nitrate, NaCl, Tween 60 and zinc chloride were positive factors for phytase production, and that NaH2PO4 had a negative effect on phytase production.

Characterization of haloalkalophilic organic solvent tolerant protease for chitin extraction from shrimp shell waste

Halophilic organic solvent tolerant protease (HOSP) producing Paracoccus saliphilus APCMST-CS5 was isolated from the marine sediment samples and identified through 16S rRNA sequence analysis. P. saliphilus APCMST-CS5 registered maximum HOSP production of 1,321.70U/ml in the medium contained the most significant parameters such as shrimp shell powder (SSP), CaCl2, NaCl, and sardinella powder (SP), obtained through Placket-Burman and Response Surface Methods. HOSP was further purified to 22.68 fold purity with 29.71 U/mg specific activity and its molecular weight was 39kDa. The HOSP was stable at 60°C, 9.0 pH, 3.0M NaCl concentration and it also showed maximum activity at other tested parameters. Interestingly the purified HOSP showed better antibiofilm ability against tested pathogens. Also, the HOSP effectively deproteinized (85.64%) shrimp shell chitin which in turn maximum and exhibited higher antioxidant activity. The commercial and experimental shrimp shell chitin showed similar peak pattern in FTIR and 13C CP/MAS NMR spectral analysis.

In vitro-Scientific evaluation on antimicrobial, antioxidant, cytotoxic properties and phytochemical constituents of traditional coastal medicinal plants.

In the present study, evaluation of antimicrobial, antioxidant, phytochemical constituents and toxicological properties of six coastal medicinal plants (CMPs) such as Ipomea biloba, Cantharanthus roseus, Cymbopogon citratus, Vitex negundo, Thespesia populnea and Pandanus tectorius was done. The maximum antimicrobial activity was recorded by methanolic extracts of V. negundo and T. populnea against bacterial and fungal pathogens. Similarly, methanolic extracts of V. negundo and T. populnea evidenced highest antioxidant properties. The extract of T. populnea showed the maximum cytotoxicity against Artemia salina with the LC50 value of 478.11μg/ml. The hemolytic property of CMPs extracts was V. negundo (8.91%), T. populnea (21%) and C. citratus (64%) also the hemolytic index did not show any hemolysis of human erythrocytes. Furthermore, the TLC separation of V. negundo and T. populnea extracts exhibited the presence of Flavonoids (Rf-0.74) and Terpenoids (Rf-0.64). The present findings propose the promising clinical applications of selected CMPs.