Development and pharmacological evaluation of small molecular bioactives from marine algae associated heterotrophic bacteria
By: Aneetta Francis.
Contributor(s): Kajal Chakraborty (Guide).
Material type:
BookPublisher: Vellayani Department of Plant Biotechnology, College of Agriculture 2020Description: 89p.Subject(s): Plant biotechnologyDDC classification: 660.6 Online resources: Click here to access online Dissertation note: MSc Summary: Increased incidences of microbial resistance and the development of drug-resistant pathogens have triggered an urge amongst researchers focusing on the discovery of potential anti-infective compounds. The present study conducted at Marine Biotechnology Division, ICAR-CMFRI, Kochi, highlights the cultivable diversity and bioactivities of heterotrophic bacteria associated with the intertidal macroalgae of Southeast coast of India. Among the 40 bacteria isolated, the majority of the isolates represented Gamma-proteobacteria (62 %) and the following 38 % resided in the phyla Firmicutes. The isolates were then screened for antibacterial activities against a wide spectrum of pathogens including methicillin-resistant Staphylococcus aureus by spot on lawn assay. Further, one of the most active strains belonging to the phyla Firmicutes isolated from Rhodophyceae macroalga, Laurencia papillosa, with a zone of inhibition ≥ 35 mm, was selected for bioprospecting studies. It was characterized as Bacillus velezensis MBTDLP1 (MT122835), based on integrated phenotypic and genotypic analysis. Type-I pks gene (MT394492) of 700 bp also could be amplified from the candidate bacterium. The bacterium exhibited siderophore production in CAS agar screening. The bacteria showed significant susceptibility to the commercially available antibiotics thus neglecting the chances of pathogenicity. The organic extract of the candidate bacterium was also found to display ferrous ion chelating capacity (IC50 4.2 mg/mL). The heterotrophic bacterium B. velezensis MBTDLP1 exhibited promising anti-infective properties against test pathogens which included multidrug- resistant pathogen methicillin-resistant S.aureus (MIC of 15 μg/mL). The organic extract showed antibacterial activity (MIC 7.5-15 μg/mL), antioxidant property with IC50 values from 0.1-0.9 mg/mL against ABTS and DPPH radicals, anti-inflammatory activity with IC50 0.01 mg/mL against 5-LOX, anti-diabetic property with IC50 0.1-0.4 mg/mL in correspondence to α-amylase and α-glucosidase. The organic extract also showed significant anti-cancer activity against Human breast cancer cells with IC50 0.032 mg/mL and less cytotoxicity to normal cells. Significant antibacterial activity against drug resistant bacteria together with considerable pharmacological activities combined with the presence of genes coding for bioactive secondary metabolites revealed that this marine symbiotic bacterium could be used against the dilemma.
| Item type | Current location | Collection | Call number | Status | Date due | Barcode |
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Theses
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KAU Central Library, Thrissur Theses | Thesis | 660.6 ANE/DE PG (Browse shelf) | Available | 175112 |
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MSc
Increased incidences of microbial resistance and the development of drug-resistant pathogens have triggered an urge amongst researchers focusing on the discovery of potential anti-infective compounds. The present study conducted at Marine Biotechnology Division, ICAR-CMFRI, Kochi, highlights the cultivable diversity and bioactivities of heterotrophic bacteria associated with the intertidal macroalgae of Southeast coast of India. Among the 40 bacteria isolated, the majority of the isolates represented Gamma-proteobacteria (62 %) and the following 38 % resided in the phyla Firmicutes. The isolates were then screened for antibacterial activities against a wide spectrum of pathogens including methicillin-resistant Staphylococcus aureus by spot on lawn assay. Further, one of the most active strains belonging to the phyla Firmicutes isolated from Rhodophyceae macroalga, Laurencia papillosa, with a zone of inhibition ≥ 35 mm, was selected for bioprospecting studies. It was characterized as Bacillus velezensis MBTDLP1 (MT122835), based on integrated phenotypic and genotypic analysis. Type-I pks gene (MT394492) of 700 bp also could be amplified from the candidate bacterium. The bacterium exhibited siderophore production in CAS agar screening. The bacteria showed significant susceptibility to the commercially available antibiotics thus neglecting the chances of pathogenicity. The organic extract of the candidate bacterium was also found to display ferrous ion chelating capacity (IC50 4.2 mg/mL). The heterotrophic bacterium B. velezensis MBTDLP1 exhibited promising anti-infective properties against test pathogens which included multidrug- resistant pathogen methicillin-resistant S.aureus (MIC of 15 μg/mL). The organic extract showed antibacterial activity (MIC 7.5-15 μg/mL), antioxidant property with IC50 values from 0.1-0.9 mg/mL against ABTS and DPPH radicals, anti-inflammatory activity with IC50 0.01 mg/mL against 5-LOX, anti-diabetic property with IC50 0.1-0.4 mg/mL in correspondence to α-amylase and α-glucosidase. The organic extract also showed significant anti-cancer activity against Human breast cancer cells with IC50 0.032 mg/mL and less cytotoxicity to normal cells. Significant antibacterial activity against drug resistant bacteria together with considerable pharmacological activities combined with the presence of genes coding for bioactive secondary metabolites revealed that this marine symbiotic bacterium could be used against the dilemma.
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