Antibacterial Potential and Apoptosis Induction by Pigments from the Endophyte Burkholderia sp. WYAT7

Development and challenges of antimicrobial peptide delivery strategies in bacterial therapy: A review

The escalating global prevalence of antimicrobial resistance poses a critical threat, prompting concerns about its impact on public health. This predicament is exacerbated by the acute shortage of novel antimicrobial agents, a scarcity attributed to the rapid surge in bacterial resistance. This review delves into the realm of antimicrobial peptides, a diverse class of compounds ubiquitously present in plants and animals across various natural organisms. Renowned for their intrinsic antibacterial activity, these peptides provide a promising avenue to tackle the intricate challenge of bacterial resistance. However, the clinical utility of peptide-based drugs is hindered by limited bioavailability and susceptibility to rapid degradation, constraining efforts to enhance the efficacy of bacterial infection treatments. The emergence of nanocarriers marks a transformative approach poised to revolutionize peptide delivery strategies. This review elucidates a promising framework involving nanocarriers within the realm of antimicrobial peptides. This paradigm enables meticulous and controlled peptide release at infection sites by detecting dynamic shifts in microenvironmental factors, including pH, ROS, GSH, and reactive enzymes. Furthermore, a glimpse into the future reveals the potential of targeted delivery mechanisms, harnessing inflammatory responses and intricate signaling pathways, including adenosine triphosphate, macrophage receptors, and pathogenic nucleic acid entities. This approach holds promise in fortifying immunity, thereby amplifying the potency of peptide-based treatments. In summary, this review spotlights peptide nanosystems as prospective solutions for combating bacterial infections. By bridging antimicrobial peptides with advanced nanomedicine, a new therapeutic era emerges, poised to confront the formidable challenge of antimicrobial resistance head-on.

Production, characterization and in vitro biological activities of crude pigment from endophytic Micrococcus luteus associated with Avicennia marina

Due to their non-toxic and non-carcinogenic nature, biopigments have a phenomenal benefit over synthetic pigments, making them a desirable source for human utilization and a potential alternative to traditional synthetic pigments that are hazardous to the environment and public health. Endosymbiotic interactions between mangrove plants and bacteria could provide an alternate source for the synthesis of unique compounds with potent biomedical applications. Pigmented endophytic bacteria were screened from the explants of Avicennia marina, a mangrove plant, and identified as Micrococcus luteus by molecular characterization. The intracellular pigment was successfully extracted using the sonication-assisted solvent extraction method, and screening factors impacting the pigmentation bioprocess were determined using a one-factor-at-a-time approach. The endophyte produced yellow pigment in the liquid medium, with the maximum growth and pigment production recorded in nutrient broth at 37 ℃ and pH 7 after 96 h of incubation, while the maximum accumulation of pigment was observed in the media supplemented with glucose and tryptone as carbon and nitrogen sources, respectively. The extracted crude pigment was further characterized by ultraviolet, followed by Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry. The obtained crude pigment has been evaluated for its antioxidant and anticancer activity by various assays, such as DPPH radical scavenging activity, FRAP assay, superoxide anion and nitric oxide radical scavenging, metal chelating activity, phosphomolybdenum assay, and MTT assay, respectively, at varying concentrations. The results of our study revealed that the yellow pigment produced by the endophyte showed significant dose-dependent antioxidant and anticancer activity.

Carotenoid from marine Bacillus infantis: production, extraction, partial characterization, and its biological activity

Marine bacteria could serve as a potential source of natural carotenoids. Bacillus infantis, (Accession number OP601610), a bacterium with the ability to synthesize carotenoids, was isolated from the marine environment and used in this investigation to produce an orange pigment. Additionally, the production, extraction, partial characterization, and biological activity of orange pigment are reported in the current work. The orange pigment was identified as a carotenoid group of pigment by UV-Visible spectrophotometry, FTIR (Fourier-transform infrared spectroscopy), and TLC (Thin-layer chromatography) characterization of the methanolic extract of the pigment. The pigment showed antimicrobial activity against four Gram-negative strains (Pseudomonas aeruginosa, Shigella dysenteriae, Salmonella enterica ser. typhi MTCC 733, and Serratia marcescens MTCC 86), three Gram-positive strains (Bacillus megaterium MTCC 3353, Staphylococcus aureus MTCC 96, and Staphylococcus epidermis MTCC 3382), and antioxidant potential by ABTS [2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)], DPPH (2,2-diphenyl 1-picrylhydrazyl), H₂O₂ (hydrogen peroxide), FRAP (Ferric reducing antioxidant power), and phospho-molybdate methods. These findings demonstrate that the carotenoids of the strains under research provide intriguing possibilities for biotechnological applications.

Endophytic Burkholderia: Multifunctional roles in plant growth promotion and stress tolerance

The genus Burkholderia has proven potential in improving plant performance. In recent decades, a huge diversity of Burkholderia spp. have been reported with diverse capabilities of plant symbiosis which could be harnessed to enhance plant growth and development. Colonization of endophytic Burkholderia spp. have been extensively studied through techniques like advanced microscopy, fluorescent labelling, PCR based assays, etc., and found to be systemically distributed in plants. Thus, use of these biostimulant microbes holds the promise of improving quality and quantity of crops. The endophytic Burkholderia spp. have been found to support plant functions along with boosting nutrient availability, especially under stress. Endophytic Burkholderia spp. improve plant survival against deadly pathogens via mechanisms like competition, induced systemic resistance, and antibiosis. At the same time, they are reported to extend plant tolerance towards multiple abiotic stresses especially drought, salinity, and cold. Several attempts have been made to decipher the potential of Burkholderia spp. by genome mining, and these bacteria have been found to harbour genes for plant symbiosis and for providing multiple benefits to host plants. Characteristics specific for host recognition and nutrient acquisition were confirmed in endophytic Burkholderia by genomics and proteomics-based studies. This could pave the way for harnessing Burkholderia spp. for biotechnological applications like biotransformation, phytoremediation, insecticidal activity, antimicrobials, etc. All these make Burkholderia spp. a promising microbial agent in improving plant performance under multiple adversities. Thus, the present review highlights critical roles of endophytic Burkholderia spp., their colonization, alleviation of biotic and abiotic stresses, biotechnological applications and genomic insights.

A novel carotenoid from Metabacillus idriensis LipT27: production, extraction, partial characterization, biological activities and use in textile dyeing

The present study reports the production, extraction, partial characterization, biological activities and use in textile dyeing of an orange pigment from Metabacillus idriensis strain LipT27 (MN818522.2). Pigment production occurred with 400 µg carotenoid/g biomass yield. Characterization of the methanol extracts of pigment by UV-Visible spectrophotometry, TLC, NMR, and FTIR indicated that the pigment was a carotenoid group pigment. The pigment exhibited antibacterial activity against Yersinia enterocolitica, Staphylococcus aureus, and Escherichia coli and antioxidant potential in DPPH and ABTS assays. In addition, the crude pigment was used in dyeing cotton fabrics. The first carotenoid from M. idriensis, which has strong antibacterial and antioxidant properties and also has the potential to be used as a dyeing agent for textiles, suggests that it can be used as a natural colorant substitute to synthetic dyes.

Isolation, Characterization, and Antibiofilm Activity of Pigments Synthesized by Rhodococcus sp. SC1

Infections from multi-drug resistant bacteria and biofilms constitute a serious problem worldwide. There is a need for new antibacterial and antibiofilm compounds in the fight against infectious diseases. In recent years, pigment-producing microorganisms have drawn a great deal of attention as a promising source for antibacterial and antibiofilm compounds. Here, we report the antibacterial and antibiofilm activity of pigments synthesized by bacteria isolated from soil. This study aimed to perform an evaluation of the antibacterial, antibiofilm, and characteristic of crude pigments from Rhodococcus sp. SC1 isolates. The total pigment extract exhibited antibacterial activity against Gram-positive and Gram-negative reference bacteria with required minimum inhibitory concentration (MIC) values ranging from 64 to 256 µg/ml. Moreover, it reduced biofilm formation of Gram-negative reference bacteria at sub-MIC concentration. For characterization of the pigments, UV-absorbance, thin layer chromatography, fourier transform infrared spectroscopy, and QTOF-LC/MS analyses were performed. The results of this study showed that pigments of Rhodococcus sp. SC1 isolates can be a candidate for medical applications.