scholarly journals In vitro Antibacterial Potential of Halophilic Bacterial Secondary Metabolites from Salted Fish

2016 ◽  
Vol 8 (04) ◽  
Author(s):  
G. Prakash Williams ◽  
Anju Anand ◽  
Parvathy A. ◽  
Rakky C. Raj ◽  
Robert Raju ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Bacillus Subtilis ◽  
Secondary Metabolites ◽  
Xanthomonas Campestris ◽  
Halophilic Bacteria ◽  
Resistance Pattern ◽  
Salted Fish ◽  
Wide Range ◽  
Fish Samples

Living organisms can be found over a wide range of extreme conditions. Most of the organisms living in extreme environments (i.e, extremophiles) belong to the prokaryotes. Halophiles are interesting class of extremophilic organisms that have adapted to harsh, hypersaline conditions. They are able to compete successfully for water and resist the denaturing effects of salts. The present study was an investigation on the in vitro antibacterial effect of secondary metabolites from halophilic bacteria isolated from salted fish samples. The cured salted fish samples were collected and enumerated using halophilic Nutrient Agar supplemented with 4% NaCl. The isolated and purified bacterial cultures are numbered as SF1, SF2, SF3, SF4 and SF5 are further identified using VITEK 2 system as Bacillus vallismortis, Ralstonia mannitolytica, Bacillus subtilis, Rhizoboum radiobacter and Kocuria kristina. Growth kinetics of halobacterial isolates were determined by spectrophotometric assay. The antibiotic resistance pattern of tested pathogenic microorganisms using the commercial antibiotics was screened and almost all the tested microorganisms are resistant to Penicillin. The antimicrobial activity of secondary metabolites of halophilic bacteria against drug resistant microbes was assessed using the Agar well diffusion assay. Among the different extracts of the halophilic bacteria, the chloroform extracts of R. mannitolytica showed maximum antibacterial activity against Bacillus subtilis MTCC 441 and Xanthomonas campestris MTCC 2286. The results of antimicrobial activity are considerable because it enables the identification of potential secondary metabolites present in marine halophilic bacteria, which act as source of innumerable therapeutic agents. Further research is highly warranted to find out the active principle responsible for the antibacterial property and to elucidate the structure of particular compound.

scholarly journals Genomic and Chemical Diversity of Bacillus subtilis Secondary Metabolites against Plant Pathogenic Fungi

mSystems ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Heiko T. Kiesewalter ◽  
Carlos N. Lozano-Andrade ◽  
Mario Wibowo ◽  
Mikael L. Strube ◽  
Gergely Maróti ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Secondary Metabolites ◽  
Pathogenic Fungus ◽  
Gene Clusters ◽  
Chemical Diversity ◽  
Biosynthetic Gene ◽  
Nonribosomal Peptide ◽  
Content Type ◽  
Wide Range

ABSTRACT Bacillus subtilis produces a wide range of secondary metabolites providing diverse plant growth-promoting and biocontrol abilities. These secondary metabolites include nonribosomal peptides with strong antimicrobial properties, causing either cell lysis, pore formation in fungal membranes, inhibition of certain enzymes, or bacterial protein synthesis. However, the natural products of B. subtilis are mostly studied either in laboratory strains or in individual isolates, and therefore, a comparative overview of secondary metabolites from various environmental B. subtilis strains is missing. In this study, we isolated 23 B. subtilis strains from 11 sampling sites, compared the fungal inhibition profiles of wild types and their nonribosomal peptide mutants, followed the production of targeted lipopeptides, and determined the complete genomes of 13 soil isolates. We discovered that nonribosomal peptide production varied among B. subtilis strains coisolated from the same soil samples. In vitro antagonism assays revealed that biocontrol properties depend on the targeted plant pathogenic fungus and the tested B. subtilis isolate. While plipastatin alone is sufficient to inhibit Fusarium spp., a combination of plipastatin and surfactin is required to hinder growth of Botrytis cinerea. Detailed genomic analysis revealed that altered nonribosomal peptide production profiles in specific isolates are due to missing core genes, nonsense mutation, or potentially altered gene regulation. Our study combines microbiological antagonism assays with chemical nonribosomal peptide detection and biosynthetic gene cluster predictions in diverse B. subtilis soil isolates to provide a broader overview of the secondary metabolite chemodiversity of B. subtilis. IMPORTANCE Secondary or specialized metabolites with antimicrobial activities define the biocontrol properties of microorganisms. Members of the Bacillus genus produce a plethora of secondary metabolites, of which nonribosomally produced lipopeptides in particular display strong antifungal activity. To facilitate the prediction of the biocontrol potential of new Bacillus subtilis isolates, we have explored the in vitro antifungal inhibitory profiles of recent B. subtilis isolates, combined with analytical natural product chemistry, mutational analysis, and detailed genome analysis of biosynthetic gene clusters. Such a comparative analysis helped to explain why selected B. subtilis isolates lack the production of certain secondary metabolites.

scholarly journals Genomic and chemical diversity of Bacillus subtilis secondary metabolites against plant pathogenic fungi

2020 ◽  
Author(s):  
Heiko T. Kiesewalter ◽  
Carlos N. Lozano-Andrade ◽  
Mario Wibowo ◽  
Mikael L. Strube ◽  
Gergely Maróti ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Secondary Metabolites ◽  
Mutational Analysis ◽  
Pathogenic Fungus ◽  
Pathogenic Fungi ◽  
Gene Clusters ◽  
Chemical Diversity ◽  
Biosynthetic Gene ◽  
Wide Range

ABSTRACTBacillus subtilis produces a wide range of secondary metabolites providing diverse plant-growth-promoting and biocontrol abilities. These secondary metabolites include non-ribosomal peptides (NRPs) with strong antimicrobial properties, causing either cell lysis, pore formation in fungal membranes, inhibition of certain enzymes, or bacterial protein synthesis. However, the natural products of B. subtilis are mostly studied either in laboratory strains or in individual isolates and therefore, a comparative overview of B. subtilis secondary metabolites is missing.In this study, we have isolated 23 B. subtilis strains from eleven sampling sites, compared the fungal inhibition profiles of wild types and their NRPs mutants, followed the production of targeted lipopeptides, and determined the complete genomes of 13 soil isolates. We discovered that non-ribosomal peptide production varied among B. subtilis strains co-isolated from the same soil samples. In vitro antagonism assays revealed that biocontrol properties depend on the targeted plant pathogenic fungus and the tested B. subtilis isolate. While plipastatin alone is sufficient to inhibit Fusarium sp., a combination of plipastatin and surfactin is required to hinder the growth of Botrytis cinerea. Detailed genomic analysis revealed that altered NRP production profiles in certain isolates is due to missing core genes, nonsense mutation, or potentially altered gene regulation.Our study combines microbiological antagonism assays with chemical NRPs detection and biosynthetic gene cluster predictions in diverse B. subtilis soil isolates to provide a broader overview of the secondary metabolite chemodiversity of B. subtilis.IMPORTANCESecondary or specialized metabolites with antimicrobial activities define the biocontrol properties of microorganisms. Members of the Bacillus genus produce a plethora of secondary metabolites, of which non-ribosomally produced lipopeptides in particular display strong antifungal activity. To facilitate prediction of the biocontrol potential of new Bacillus subtilis isolates, we have explored the in vitro antifungal inhibitory profiles of recent B. subtilis isolates, combined with analytical natural product chemistry, mutational analysis, and detailed genome analysis of biosynthetic gene clusters. Such a comparative analysis helped to explain why selected B. subtilis isolates lack production of certain secondary metabolites.

Associated microflora of medicinal ferns: biotechnological potentials and possible applications

2016 ◽  
Vol 5 (03) ◽  
pp. 4927 ◽  
Author(s):  
Shubhi Srivastava ◽  
Paul A. K.
Keyword(s):  
Secondary Metabolites ◽  
Growth Promotion ◽  
Biological Activities ◽  
Hydrolytic Enzymes ◽  
In Vitro Production ◽  
Wide Range ◽  
Negative Effect ◽  
Bacteria And Fungi

Plant associated microorganisms that colonize the upper and internal tissues of roots, stems, leaves and flowers of healthy plants without causing any visible harmful or negative effect on their host. Diversity of microbes have been extensively studied in a wide variety of vascular plants and shown to promote plant establishment, growth and development and impart resistance against pathogenic infections. Ferns and their associated microbes have also attracted the attention of the scientific communities as sources of novel bioactive secondary metabolites. The ferns and fern alleles, which are well adapted to diverse environmental conditions, produce various secondary metabolites such as flavonoids, steroids, alkaloids, phenols, triterpenoid compounds, variety of amino acids and fatty acids along with some unique metabolites as adaptive features and are traditionally used for human health and medicine. In this review attention has been focused to prepare a comprehensive account of ethnomedicinal properties of some common ferns and fern alleles. Association of bacteria and fungi in the rhizosphere, phyllosphere and endosphere of these medicinally important ferns and their interaction with the host plant has been emphasized keeping in view their possible biotechnological potentials and applications. The processes of host-microbe interaction leading to establishment and colonization of endophytes are less-well characterized in comparison to rhizospheric and phyllospheric microflora. However, the endophytes are possessing same characteristics as rhizospheric and phyllospheric to stimulate the in vivo synthesis as well as in vitro production of secondary metabolites with a wide range of biological activities such as plant growth promotion by production of phytohormones, siderophores, fixation of nitrogen, and phosphate solubilization. Synthesis of pharmaceutically important products such as anticancer compounds, antioxidants, antimicrobials, antiviral substances and hydrolytic enzymes could be some of the promising areas of research and commercial exploitation.

Study of Red Halophilic Bacteria in Solar Salt and Salted Fish: II. Bacto-oxgall as a Selective Agent for Differentiation

1956 ◽  
Vol 13 (2) ◽  
pp. 195-199 ◽  
Author(s):  
H. P. Dussault
Keyword(s):  
Halophilic Bacteria ◽  
Partial Identification ◽  
Selective Medium ◽  
Selective Agent ◽  
Simple Method ◽  
Solar Salt ◽  
Salted Fish ◽  
Low Concentrations ◽  
Fish Samples

A simple method, based on oxgall tolerance, is proposed for differentiating red halophilic bacteria commonly found in solar salt and discoloured salted codfish. Tests carried out on 18 strains isolated from various sources have shown that the rod forms are inhibited by low concentrations of Bacto-oxgall and that the coccus forms tolerate relatively high ones. Bacto-oxgall can thus be used as the basis of a simple selective medium. This test has been found useful for the isolation, purification and partial identification of unidentified strains and also for determining the relative proportions of the two main types of red halophilic bacteria present in solar salt and salted fish samples.

scholarly journals Subinhibitory Antimicrobial Concentrations: A Review of In Vitro and In Vivo Data

1992 ◽  
Vol 3 (4) ◽  
pp. 193-201 ◽  
Author(s):  
George G Zhanel ◽  
Daryl J Hoban ◽  
Godfrey KM Harding
Keyword(s):  
Antimicrobial Activity ◽  
Animal Studies ◽  
Molecular Level ◽  
Bacterial Virulence ◽  
Antibacterial Effects ◽  
Wide Range ◽  
Immune Defences

Antimicrobial activity is not an ‘all or none’ effect. An increase in the rate and extent of antimicrobial action is usually observed over a wide range of antimicrobial concentrations. Subinhibitory antimicrobial concentrations are well known to produce significant antibacterial effects, and various antimicrobials at subinhibitory concentrations have been reported to inhibit the rate of bacterial growth. Bacterial virulence may be increased or decreased by subinhibitory antimicrobial concentrations by changes in the ability of bacteria to adhere to epithelial cells or by alterations in bacterial susceptibility to host immune defences. Animal studies performed in rats, hamsters and rabbits demonstrate decreased bacterial adherence, reduced infectivity and increased survival of animals treated with subinhibitory antimicrobial concentrations compared to untreated controls. The major future role of investigation of subinhibitory antimicrobial concentrations will be to define more fully, at a molecular level, how antimicrobials exert their antibacterial effects.

scholarly journals In vitro antimicrobial activity of the organic extract of Cladonia substellata Vainio and usnic acid against Staphylococcus spp. obtained from cats and dogs

2017 ◽  
Vol 37 (4) ◽  
pp. 368-378 ◽  
Author(s):  
Jusciêne B. Moura ◽  
Agueda C. de Vargas ◽  
Gisele V. Gouveia ◽  
João J. de S. Gouveia ◽  
Juracy C. Ramos-Júnior ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Biological Activities ◽  
Meca Gene ◽  
Usnic Acid ◽  
Organic Extract ◽  
In Vitro Antimicrobial Activity ◽  
Low Concentrations ◽  
Wide Range ◽  
Staphylococcus Spp

ABSTRACT: Cladonia substellata Vainio is a lichen found in different regions of the world, including the Northeast of Brazil. It contains several secondary metabolites with biological activity, including usnic acid, which has exhibited a wide range of biological activities. The aim of this study was to evaluate the in vitro antimicrobial activity of the organic extract of C. substellata and purified usnic acid. Initially, Staphylococcus spp., derived from samples of skin and ears of dogs and cats with suspected pyoderma and otitis, were isolated and analyzed. In antimicrobial susceptibility testing against Staphylococcus spp., 77% (105/136) of the isolates were resistant to the antimicrobials tested. In the assessment of biofilm production, 83% (113/136) were classified as producing biofilm. In genetic characterization, 32% (44/136) were positive for blaZ, no isolate (0/136) was positive for the mecA gene, and 2% (3/136) were positive for the icaD gene. The in vitro antimicrobial activity of the organic extract of C. substellata and purified usnic acid against Staphylococcus spp. ranged from 0.25mg/mL to 0.0019mg/mL, inhibiting bacterial growth at low concentrations. The substances were more effective against biofilm-producing bacteria (0.65mg/mL-0.42mg/mL) when compared to non-biofilm producing bacteria (2.52mg/mL-2.71mg/mL). Usnic acid and the organic extract of C. substellata can be effective in the treatment of pyoderma and otitis in dogs and cats caused by Staphylococcus spp.

scholarly journals EVALUATION OF IN VITRO ANTI-INFLAMMATORY AND ANTIMICROBIAL ACTIVITY OF AQUEOUS AND METHANOLIC SEED EXTRACTS OF CITRULLUS LANATUS

2017 ◽  
Vol 9 (5) ◽  
pp. 29
Author(s):  
Iswariya S. ◽  
Uma T. S.
Keyword(s):  
Antimicrobial Activity ◽  
Bacillus Subtilis ◽  
Aqueous Extract ◽  
Seed Extract ◽  
Inflammatory Activity ◽  
Diffusion Method ◽  
Klebsiella Pneumonia ◽  
Anti Inflammatory ◽  
Seed Extracts

Objective: The present study was designed to identify the bioactive phytochemicals and its antibacterial and in vitro anti-inflammatory potential of aqueous and methanolic seed extract of Citrullus lanatus.Methods: The phytochemical screening of both the aqueous and methanolic seed extract was carried out qualitatively to identify the major Phyto-constituents present in the extracts. The antimicrobial activity of the extracts was evaluated against six pathogenic bacterial strains by agar well diffusion method and the Minimum inhibitory concentration (MIC) was determined by broth dilution method. In vitro anti-inflammatory activity of C. lanatus seed extracts was evaluated by using human red blood cell (HRBC) membrane stabilization and inhibition of albumin denaturation method.Results: The results of the study indicated that both the extracts of the seed having antimicrobial activity, while the methanolic extract showed more significant activity against the tested organism than aqueous extract. Methanol extract had the lowest MIC of 1.562 mg/ml against Escherichia coli, Staphylococcus aureus, Klebsiella pneumonia, Pseudomonas aeruginosa and Bacillus subtilis, whereas in aqueous extract was highly sensitive to Bacillus subtilis, E. coli and Klebsiella pneumonia with MIC of 3.125 and 6.25 mg/ml, respectively. Methanolic extracts exerted comparative higher anti-inflammatory activity than aqueous extract.Conclusion: Present study provides a firm evidence to support that the synergistic effect of C. lanatus seed extracts having potent anti-inflammatory and antimicrobial property, which might serve as an effective drug for various microbial infections and inflammatory disorders.

scholarly journals Apis andreniformis associated Actinomycetes show antimicrobial activity against black rot pathogen (Xanthomonas campestris pv. campestris)

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12097
Author(s):  
Yaowanoot Promnuan ◽  
Saran Promsai ◽  
Wasu Pathom-aree ◽  
Sujinan Meelai
Keyword(s):  
Antimicrobial Activity ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Honey Bee ◽  
Pseudomonas Syringae ◽  
Xanthomonas Campestris ◽  
Pathogenic Bacteria ◽  
Rrna Gene ◽  
Apis Andreniformis

This study aimed to investigate cultivable actinomycetes associated with rare honey bee species in Thailand and their antagonistic activity against plant pathogenic bacteria. Actinomycetes were selectively isolated from the black dwarf honey bee (Apis andreniformis). A total of 64 actinomycete isolates were obtained with Streptomyces as the predominant genus (84.4%) followed by Micromonospora (7.8%), Nonomuraea (4.7%) and Actinomadura (3.1%). All isolates were screened for antimicrobial activity against Xanthomonas campestris pv. campestris, Pectobacterium carotovorum and Pseudomonas syringae pv. sesame. Three isolates inhibited the growth of X. campestris pv. campestris during in vitro screening. The crude extracts of two isolates (ASC3-2 and ASC5-7P) had a minimum inhibitory concentration (MIC) of 128 mg L−1against X. campestris pv. campestris. For isolate ACZ2-27, its crude extract showed stronger inhibitory effect with a lower MIC value of 64 mg L−1 against X. campestris pv. campestris. These three active isolates were identified as members of the genus Streptomyces based on their 16S rRNA gene sequences. Phylogenetic analysis based on the maximum likelihood algorithm showed that isolate ACZ2-27, ASC3-2 and ASC5-7P were closely related to Streptomyces misionensis NBRC 13063T (99.71%), Streptomyces cacaoi subsp. cacaoi NBRC 12748T (100%) and Streptomyces puniceus NBRC 12811T (100%), respectively. In addition, representative isolates from non-Streptomyces groups were identified by 16S rRNA gene sequence analysis. High similarities were found with members of the genera Actinomadura, Micromonospora and Nonomuraea. Our study provides evidence of actinomycetes associated with the black dwarf honey bee including members of rare genera. Antimicrobial potential of these insect associated Streptomyces was also demonstrated especially the antibacterial activity against phytopathogenic bacteria.

scholarly journals In Vitro Antifungal Activities of a Series of Dication-Substituted Carbazoles, Furans, and Benzimidazoles

1998 ◽  
Vol 42 (10) ◽  
pp. 2503-2510 ◽  
Author(s):  
Maurizio Del Poeta ◽  
Wiley A. Schell ◽  
Christine C. Dykstra ◽  
Susan K. Jones ◽  
Richard R. Tidwell ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Candida Albicans ◽  
Fusarium Solani ◽  
Antifungal Agents ◽  
Antifungal Drugs ◽  
Inhibitory Compounds ◽  
Wide Range ◽  
Fluconazole Resistant ◽  
Resistant Strains

ABSTRACT Aromatic dicationic compounds possess antimicrobial activity against a wide range of eucaryotic pathogens, and in the present study an examination of the structures-functions of a series of compounds against fungi was performed. Sixty-seven dicationic molecules were screened for their inhibitory and fungicidal activities againstCandida albicans and Cryptococcus neoformans. The MICs of a large number of compounds were comparable to those of the standard antifungal drugs amphotericin B and fluconazole. Unlike fluconazole, potent inhibitory compounds in this series were found to have excellent fungicidal activities. The MIC of one of the most potent compounds against C. albicans was 0.39 μg/ml, and it was the most potent compound against C. neoformans (MIC, ≤0.09 μg/ml). Selected compounds were also found to be active againstAspergillus fumigatus, Fusarium solani,Candida species other than C. albicans, and fluconazole-resistant strains of C. albicans and C. neoformans. Since some of these compounds have been safely given to animals, these classes of molecules have the potential to be developed as antifungal agents.

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