Understanding the Dynamics of Human Defensin Antimicrobial Peptides: Pathogen Resistance and Commensal Induction.

Antimicrobial peptides (AMPs), also known as host defense peptides, are petite molecules with inherent microbicidal properties that are synthesized by the host's innate immune response. These peptides serve as an initial barrier against pathogenic microorganisms, effectively eliminating them. Human defensin (HD) AMPs represent a prominent group of peptides involved in the innate immune response of humans. These peptides are primarily produced by neutrophils and epithelial cells, serving as a crucial defense mechanism against invading pathogens. The extensive research conducted has focused on the broad spectrum of antimicrobial activities and multifaceted immunomodulatory functions exhibited by human defensin AMPs. During the process of co-evolution between hosts and bacterial pathogens, bacteria have developed the ability to recognize and develop an adaptive response to AMPs to counterattack their bactericidal activity by different antibiotic-resistant mechanisms. However, numerous non-pathogenic commensal bacteria elicit the upregulation of defensins as a means to surmount the resistance mechanisms implemented by pathogens. The precise mechanism underlying the induction of HD by commensal organisms remains to be fully understood. This review summarizes the most recent research on the expression of human defensin by pathogens and discusses the various defense mechanisms used by pathogens to counter host AMP production. We also mention recent developments in the commensal induction of defensin AMPs. A better knowledge of the pathogens' defensin AMP resistance mechanisms and commensals' induction of AMP expression may shed light on the creation of fresh antibacterial tactics to get rid of bacterial infection.

Biodegradation of di-(2-ethylhexyl) phthalate by novel Rhodococcus sp. PFS1 strain isolated from paddy field soil.

Di-(2-ethylhexyl)-phthalate (DEHP) is the phthalate ester frequently utilized as a plasticizer, commonly found in cosmetics, packaging materials; moreover, it has carcinogenic and mutagenic effects on humans. In the current study, we isolated the soil bacterium Rhodococcus sp. PFS1 and to assess its DEHP degradation ability in various environmental conditions. The strain PFS1 was isolated from paddy field soil and identified by the 16S rRNA sequencing analyses. The strain PFS1 was examined for its biodegradation ability of DEHP at various pH, temperature, salt concentration, glucose concentration, and high and low concentrations of DEHP. Moreover, the biodegradation of DEHP at a contaminated soil environment by strain PFS1 was assessed. Further, the metabolic pathway of DEHP degradation by PFS1 was analyzed by HPLC-MS analysis. The results showed that the strain PFS1 effectively degraded the DEHP at neutral pH and temperature 30 °C; moreover, expressed excellent DEHP degradation at the high salt concentration (up to 50 g/L). The strain PFS1 was efficiently degraded the different tested phthalate esters (PAEs) up to 90%, significantly removed the DEHP contamination in soil along with native organisms which are present in soil up to 94.66%; nevertheless, the PFS1 alone degraded the DEHP up to 87.665% in sterilized soil. According to HPLC-MS analysis, DEHP was degraded into phthalate (PA) by PFS1 strain via mono(2-ethylehxyl) phthalate (MEHP); then PA was utilized for cell growth. These results suggest that Rhodococcus sp. PFS1 has excellent potential to degrade DEHP at various environmental conditions especially in contaminated paddy field soil.

Triterpenoid compound betulin attenuates allergic airway inflammation by modulating antioxidants, inflammatory cytokines and tissue transglutaminase in ovalbumin-induced asthma mice model.

OBJECTIVES: This study hypothesized that to analyse the anti-inflammatory effect of triterpenoid compound betulin in ovalbumin (OVA)-induced asthmatic mice. METHODS: In this study, betulin was intraperitoneally administered in OVA-challenged and sensitized mice. The effect of betulin on inflammatory cells, lung function, reactive oxygen species (ROS) production, antioxidants status, oxidative stress markers, serum IgE level and inflammatory cytokines status in BALF was examined by enzyme-linked immunosorbent assay. The expression of tTG, TGF-ß1, MMP-9 and TIMP-1 in lung tissue was scrutinized by RT-qPCR analysis, and the expression of TREM-1, p-IκB-α and NF-κBp65 proteins in lung tissue was examined by western blot analysis. KEY FINDINGS: We found that the betulin treatment has effectively attenuated the proliferation of inflammatory cells, reduced the ROS generation, elevated the antioxidant enzymes and attenuated the level of oxidative markers in asthma induced mice. Moreover, reduced the level of serum IgE and pro-inflammatory cytokines, and increased the anti-inflammatory cytokine IFN-γ. Betulin treatment down-regulated the expression of MMP-9, tTG and TGF-ß1 genes; moreover, betulin treatment effectively down-regulated the TREM-1, p-IκB-α and NF-κBp65 proteins level in lung. CONCLUSION: Betulin exhibited effective anti-asthmatic activity by attenuating the accumulation of inflammatory cells, expression of tTG, TGF-ß1 and MMP-9 genes in lung tissue.

Influence of long-term organic and conventional fertilization on bacterial communities involved in bioelectricity production from paddy field-microbial fuel cells.

Soils are rich in organics, particularly those that support the growth of plants. These organics are possible sources of sustainable energy, and a microbial fuel cell (MFC) system can potentially be used for this purpose. In this, the soil organic content expelled from plant root was possibly converted into electrical energy through the microbial metabolic process. The integration of MFC systems with living plant root system is a novel approach, which will facilitate sustainable resource for energy production. Therefore, the objective of this study is to electrochemically evaluate the paddy field MFCs (PF-MFCs) performance and methane emission under organic and conventional fertilization systems in paddy fields, and its impact on bacterial communities involved in bioelectricity production. Graphite (anode) and carbon (cathode) electrode MFC systems were configured and assembled in organic and conventionally fertilized paddy fields. The anode and bulk soil-associated bacterial communities were examined using high-throughput Illumina MiSeq sequencing platform. Our results revealed that the maximum electricity production and power density were observed in CFPF-MFC with less methane emission compared to OFPF-MFC. The next-generation sequencing (NGS) libraries showed that the bacterial population was significantly increased in the organic-fertilized field and the enhanced occurrence of the Geobacteraceae family in CFPF-MFC anode. By enhancing Geobacteraceae occurrence on the anode, the conventional fertilization improved the bioelectricity production with less methane emission. Further extension in the establishment of plant MFCs in various sedimentary environments will solve the global energy crisis.