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Microscopic study on colonization and antimicrobial property of endophytic bacteria associated with ethnomedicinal plants of Meghalaya.

ABSTRACT: Microscopic visualization using transmission electron microscopy (TEM) can provide a better understanding of endophytic colonization within ethnomedicinal plants. Bacterial endophytes were found attached to the host cell wall colonizing the aerenchyma and intercellular spaces of the epidermis and outer cortex except the vascular system. Colonization was non-uniform as single cells, doublets or in the form of microcolonies. Analysis of in vivo antibacterial action of the methanolic extracts of the isolated endophytic bacteria against Gram-positive, Streptococcus pyogenes MTCC 1925 and Gram-negative, Salmonella enterica ser. paratyphi MTCC735 pathogens has revealed the morphological damages in the tested pathogens respectively, under scanning electron microscopy (SEM). Detached cell wall and cell burst were observed in Streptococcus pyogenes where as, cell blisters were shown in Salmonella enterica ser. paratyphi. The study on bacterial endophyte colonization process is important to better predict how endophytes interact with their host and establish themselves in the plant environment by procuring biocontrol activity.

SUBMITTER: War Nongkhlaw FM

PROVIDER: S-EPMC6025718 | biostudies-literature | 2017 Jul-Sep

REPOSITORIES: biostudies-literature

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Microscopic study on colonization and antimicrobial property of endophytic bacteria associated with ethnomedicinal plants of Meghalaya.

War Nongkhlaw Fenella Mary FM Joshi S R SR

Journal of microscopy and ultrastructure 20161109 3

Microscopic visualization using transmission electron microscopy (TEM) can provide a better understanding of endophytic colonization within ethnomedicinal plants. Bacterial endophytes were found attached to the host cell wall colonizing the aerenchyma and intercellular spaces of the epidermis and outer cortex except the vascular system. Colonization was non-uniform as single cells, doublets or in the form of microcolonies. Analysis of <i>in vivo</i> antibacterial action of the methanolic extract ...[more]

PMID: 30023247

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Project description:It is generally believed that endophytic microorganisms are intercellular inhabitants present in either cultivable or non-cultivable form primarily as root colonizers. The objective of this study was to determine whether the actively mobile micro-particles observed in the intracellular matrix of fresh tissue sections of banana included endophytic bacteria. Tissue sections (50-100 µm) from apical leaf sheaths of surface-disinfected suckers (cv. Grand Naine) displayed 'Brownian motion'-reminiscent abundant motile micro-particles under bright-field and phase-contrast (×1000), which appeared similar in size and motility to the pure cultures of endophytes previously isolated from banana. Observations on callus, embryonic cells and protoplasts with intact cell wall/plasma membrane confirmed their cytoplasmic nature. The motility of these entities reduced or ceased upon tissue fixation or staining with safranin/crystal violet (0.5 % w/v), but continued uninterrupted following treatment with actin-disrupting drugs, ruling out the possibility of micro-organelles like peroxisomes. Staining with 2,3,5-triphenyl tetrazolium chloride (TTC) confirmed them to be live bacteria with similar observations after dilute safranin (0.005 %) treatment. Tissue staining with SYTO-9 coupled with epi-fluorescence or confocal laser scanning microscopy showed bacterial colonization along the peri-space between cell wall and plasma membrane initially. SYTO-9 counterstaining on TTC- or safranin-treated tissue and those subjected to enzymatic permeabilization revealed the cytoplasmic bacteria. These included organisms moving freely in the cytoplasm and those adhering to the nuclear envelope or vacuoles and the intravacuolar colonizers. The observations appeared ubiquitous to different genomes and genotypes of banana. Plating the tissue homogenate on nutrient media seldom yielded colony growth. This study, supported largely by live cell video-imaging, demonstrates enormous intracellular colonization in bananas by normally non-cultivable endophytic bacteria in two niches, namely cytoplasmic and periplasmic, designated as 'Cytobacts' and 'Peribacts', respectively. The integral intracellular association with their clonal perpetuation suggests a mutualistic relationship between endophytes and the host.

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Dataset Information

Microscopic study on colonization and antimicrobial property of endophytic bacteria associated with ethnomedicinal plants of Meghalaya.

Publications

Microscopic study on colonization and antimicrobial property of endophytic bacteria associated with ethnomedicinal plants of Meghalaya.

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