Identification and antibacterial evaluation of endophytic actinobacteria from Luffa cylindrica

Abstract

The emergence of antibiotic-resistant bacteria has limited treatment options and led to the untreatable infections, thereby necessitating the discovery of new antibiotics to battel against bacteria. Natural products from endophytic actinobacteria (EA) serve as a reservoir for discovery of new antibiotics. Therefore, the current study focused on the isolation and antibacterial properties of EA isolated from Luffa cylindrica. Six strains were identified using morphological characterization, SEM analyses and 16S rRNA gene sequencing from the roots and leaves of the plant. They were taxonomically classified as Streptomycetaceae family. This is the first report on EA form L. cylindrica. The strains produced a chain of oval, cubed or cylindrical shaped spores with spiny or smooth surfaces. Three strains; KUMS-B3, KUMS-B4 and KUMS-B6 were reported as endophytes for the first time. Fifty percent of isolates were isolated from leaves samples using YECD medium. Our results showed that the sampling time and seasons may affect the bacterial diversity. All six strains had antibacterial activity against at least one of the tested bacteria S. aureus, P. aeruginosa, and E. coli. Among the strains, KUMS-B6 isolate, closely related to S. praecox, exhibited the highest antibacterial activity against both gram-positive and negative bacteria. KUMS-B6, KUMS-B5 and KUMS-B4 isolates strongly inhibited the growth of P. aeruginosa. Interestingly, the strains, isolated from leaves exhibited stronger antagonist activities compared to those isolated from the roots. The study revealed that the isolated strains from Luffa produce a plethora of bioactive substances that are potential source of new drug candidates for the treatment of infections.

Identification and anti-bacterial property of endophytic actinobacteria from Thymes kotschyanus, Allium hooshidaryae, and Cerasus microcarpa

“…The results were correlated with the bioactive compounds reported by Taechowisan, et al 28 , Taechowisan et al 29 . The results revealed that the isolates possess strong antibacterial activities against Gram-positive and Gram-negative bacteria, which is consistence with the findings of previous studies 17 , 30 , 31 . The results indicated that bacteria under the family of Streptomycetaceae presented a remarkable antagonistic activity as compared to other isolates against the test pathogens.…”

“…The properties of mycelia and spores were also examined using light and electron scanning microscopes, and then the coloration of the colonies was determined using the ISCC-NBS system 32 , 33 . Among the media used for isolation, TWYE seems to be the best medium for isolation of actinobacteria, which was in line with findings of Mahdi et al 17 who isolated three strains using the same medium. There are many reports highlighting TWYE and HVA, which are low nutrient-media, as the best media for isolating actinobacteria 27 , 34 , 35 in which corroborated our funding 22 , 23 .…”

“…Actinobacteria as one of the largest ubiquitous bacterial phylum are generally Gram-positive, having high percentage of G + C bases in their genome, mycelial growth, and spore production. They are widely distributed in both normal and extreme aquatic and terrestrial ecosystems 6 , 14 – 17 . Most of them are free-living microorganisms which use the remains of other organisms as saprophytes and also spend most of their lives as spores, especially in harsh environmental conditions 18 , 19 .…”

The anticancer and antibacterial potential of bioactive secondary metabolites derived From bacterial endophytes in association with Artemisia absinthium

“…The strains were identified to species level through the utilization of 16S rRNA gene sequences. In brief, DNA isolation was performed by the modified method of 50 , and 16S rDNA gene was amplified in polymerase chain reaction (PCR) using the genomic DNA as template and bacterial universal primers, 27F (5′-GAGTTTGAT CACTGGCTCAG-3′) and 1492 R (5′-TACGGC TACCTTGTTACGACTT-3′). The PCR products were sequenced by Sanger sequencing method.…”

Unraveling the Role of Cytochrome P450 as a Key Regulator Lantipeptide Production in Streptomyces globisporus

“…Among the phylum Actinobacteria, Streptomyces is the largest genus, characterized by gram-positive bacteria with high G-C content. Streptomyces species are known for their extensive pharmacological activities and natural ability to produce industrially relevant natural products ( Mahdi et al, 2022 ). Notably, they produce intriguing secondary metabolites such as alkaloids, flavones, macrolides, terpenoids, and polyketides, exhibiting antibacterial, antifungal, and anticancer properties ( Genilloud, 2017 ).…”