Identification of bacterial endophytes associated with traditional medicinal plant Tridax procumbens Linn.

Background: In traditional medicine, Tridax procumbens Linn. is used in the treatment of injuries and wounds. The bacterial endophytes (BEs) of medicinal plants could produce medicinally important metabolites found in their hosts; and hence, the involvement of BEs in conferring wound healing properties to T. Procumbens cannot be ruled out. But, we do not know which types of BEs are associated with T. procumbens. Objective: The objective of this study was to investigate the fast growing and cultivable BEs associated with T. procumbens. Materials and Methods: Leaves and stems of healthy T. procumbens plants were collected and cultivable BEs were isolated from surface-sterilized leaf and stem tissue samples using Luria-Bertani (LB) agar (medium) at standard conditions. A polymerase chain reaction was employed to amplify 16S rRNA coding gene fragments from the isolates. Cultivable endophytic bacterial isolates (EBIs) were identified using 16S rRNA gene nucleotide sequence similarity based method of bacterial identification. Results: Altogether, 50 culturable EBIs were isolated. 16S rRNA gene nucleotide sequences analysis using the Basic Local Alignment Search Tool (BLAST) revealed identities of the EBIs. Analysis reveals that cultivable Bacillus spp., Cronobacter sakazakii, Enterobacter spp., Lysinibacillus sphaericus, Pantoea spp., Pseudomonas spp. and Terribacillus saccharophilus are associated with T. procumbens. Conclusion: Based on the results, we conclude that 24 different types of culturable BEs are associated with traditionally used medicinal plant, T. procumbens, and require further study

Micropropagation of <i style="">Elaeis guineensis</i> Jacq. ‘Dura’: Comparison of three basal media for efficient regeneration

79-82Three basal plant tissue culture media, namely, N6, MS, and modified Y3, were compared to optimize micropropagation protocol for E. guineensis. Full strength media were used separately to regenerate plantlets directly using immature zygotic embryos (IZEs), and through somatic embryogenesis of calli obtained from IZEs. The plantlets regenerated by direct regeneration on three media were examined for shoot length and rooting percentage. For the induction of callus, somatic embryogenesis, and rooting modified Y3 medium was the most effective. In conclusion, the results indicate that modified Y3 medium is the most suitable for direct regeneration, callus induction and somatic embryogenesis in E. guineensis

Endophytic Bacteria Enterobacter hormaechei Fabricated Silver Nanoparticles and Their Antimicrobial Activity

Antimicrobial resistance (AMR), one of the greatest issues for humankind, draws special attention to the scientists formulating new drugs to prevent it. Great emphasis on the biological synthesis of silver nanoparticles (AgNPs) for utilization in single or combinatorial therapy will open up new avenues to the discovery of new antimicrobial drugs. The purpose of this study was to synthesize AgNPs following a green approach by using an endophytic bacterial strain, Enterobacter hormaechei, and to assess their antimicrobial potential against five pathogenic and four multidrug-resistant (MDR) microbes. UV-Vis spectroscopy, fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX), and zeta potential (ζ) were used to characterize the synthesized AgNPs. Endophytic E. hormaechei-mediated AgNPs (Eh-AgNPs) were represented by a strong UV-Vis absorbance peak at 418 nm within 5 min, forming spherical and polydispersed nanoparticles in the size range of 9.91 nm to 92.54 nm. The Eh-AgNPs were moderately stable with a mean ζ value of −19.73 ± 3.94 mV. The presence of amine, amide, and hydroxyl functional groups was observed from FTIR analysis. In comparison to conventional antibiotics, the Eh-AgNPs were more effective against Bacillus cereus (ATCC 10876) and Candida albicans (ATCC 10231), exhibiting 9.14 ± 0.05 mm and 8.24 ± 0.05 mm zones of inhibition (ZOIs), respectively, while displaying effective inhibitory activity with ZOIs ranging from 10.98 ± 0.08 to 13.20 ± 0.07 mm against the MDR bacteria. Eh-AgNP synthesis was rapid and eco-friendly. The results showed that Eh-AgNPs are promising antimicrobial agents that can be used in the development and formulation of new drugs to curb the menace of antimicrobial resistance in pathogenic and MDR microbes

Silver Nanoparticles Synthesized by Using the Endophytic Bacterium <i>Pantoea ananatis</i> are Promising Antimicrobial Agents against Multidrug Resistant Bacteria

Antibiotic resistance is one of the most important global problems currently confronting the world. Different biomedical applications of silver nanoparticles (AgNPs) have indicated them to be promising antimicrobial agents. In the present study, extracellular extract of an endophytic bacterium, Pantoea ananatis, was used for synthesis of AgNPs. The synthesized AgNPs were characterized by UV&#8315;Vis spectroscopy, FTIR, transmission electron microscopy (TEM), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX), and Zeta potential. The antimicrobial potential of the AgNPs against pathogenic Staphylococcus aureus subsp. aureus (ATCC 11632), Bacillus cereus (ATCC 10876), Escherichia coli (ATCC 10536), Pseudomonas aeruginosa (ATCC 10145) and Candida albicans (ATCC 10231), and multidrug resistant (MDR) Streptococcus pneumoniae (ATCC 700677), Enterococcus faecium (ATCC 700221) Staphylococcus aureus (ATCC 33592) Escherichia coli (NCTC 13351) was investigated. The synthesized spherical-shaped AgNPs with a size range of 8.06 nm to 91.32 nm exhibited significant antimicrobial activity at 6 &#956;g/disc concentration against Bacillus cereus (ATCC 10876) and Candida albicans (ATCC 10231) which were found to be resistant to conventional antibiotics. The synthesized AgNPs showed promising antibacterial efficiency at 10 &#181;g/disc concentration against the MDR strains. The present study suggests that AgNPs synthesized by using the endophytic bacterium P. ananatis are promising antimicrobial agent

Secondary Metabolites Profiling of Acinetobacter baumannii Associated with Chili (Capsicum annuum L.) Leaves and Concentration Dependent Antioxidant and Prooxidant Properties

Secondary bioactive compounds of endophytes are inevitable biomolecules of therapeutical importance. In the present study, secondary metabolites profiling of an endophytic bacterial strain, Acinetobacter baumannii, were explored using GC-MS study. Presence of antioxidant substances and antioxidant properties in chloroform (CHL), diethyl ether (DEE), and ethyl acetate (EA) crude extracts of the endophytic bacteria were studied. Total phenolic content (TPC), total flavonoid content (TFC), total antioxidant capacity (TAC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and ferrous ion chelating assay were evaluated. A total of 74 compounds were identified from the GC-MS analysis of the EA extract representing mostly alkane compounds followed by phenols, carboxylic acids, aromatic heterocyclic compounds, ketones, aromatic esters, aromatic benzenes, and alkenes. Among the two phenolic compounds, namely, phenol, 2,4-bis(1,1-dimethylethyl)- and phenol, 3,5-bis(1,1-dimethylethyl)-, the former was found in abundance (11.56%) while the latter was found in smaller quantity (0.14%). Moreover, the endophytic bacteria was found to possess a number of metal ions including Fe(II) and Cu(II) as 1307.13 ± 2.35 ppb and 42.38 ± 0.352 ppb, respectively. The extracts exhibited concentration dependent antioxidant and prooxidant properties at high and low concentrations, respectively. The presence of phenolic compounds and metal ions was believed to play an important role in the antioxidant and prooxidant potentials of the extracts. Further studies are suggested for exploring the untapped resource of endophytic bacteria for the development of novel therapeutic agents