Letters in Applied Microbiology最新文献

Psoriasis, a chronic skin autoimmune disease characterized by abnormal immune responses, is influenced by genetic and environmental factors. Recent microbiota research has revealed that short-chain fatty acids (SCFAs), metabolites produced by gut microbiota, play a pivotal role in regulating immune function and inflammation. This review examines the current literature on the relationship between gut dysbiosis, SCFA production, and immune modulation in psoriasis, focusing on emerging evidence from microbiota and immunological studies. SCFAs have been shown to influence key immune pathways, including T-cell activation and cytokine production, which are critical in psoriasis pathogenesis. Reduced SCFA levels have been observed in psoriasis, highlighting the role of gut dysbiosis in disease progression. Understanding the gut-skin axis and the role of SCFAs offers novel insights into developing effective, safe, and accessible treatments for psoriasis. Restoring microbial balance and SCFA production may serve as a promising therapeutic approach for managing psoriasis.

Heavy metal pollution is a growing environmental and public health concern, particularly due to its impact on microbial communities. Pseudomonas aeruginosa, a highly adaptable bacterium, has developed resistance to heavy metals (HMs), which is closely linked to antibiotic resistance through shared genetic and regulatory pathways. This co-resistance poses significant challenges for environmental health and antimicrobial management. Additionally, microplastics act as carriers for HMs and antibiotics, creating a compounded pollution stressor that further influences bacterial resistance patterns. This review explores the molecular mechanisms by which P. aeruginosa resists heavy metal toxicity, focusing on key adaptive strategies such as efflux systems, biofilm formation, enzymatic detoxification, and genetic modifications. These mechanisms enhance bacterial survival in contaminated environments, allowing P. aeruginosa to persist and contribute to the spread of resistance genes. The interplay between HMs, antibiotics, and microplastics underscores the complexity of pollution-driven bacterial adaptation. Addressing these issues requires a multidisciplinary approach that integrates environmental pollution control and antimicrobial resistance management. Understanding how P. aeruginosa thrives under such stress conditions is crucial for developing effective strategies to mitigate the risks associated with heavy metal contamination, antibiotic resistance, and microplastic pollution in both natural and clinical ecosystems.

Controlled environmental agriculture (CEA) is an emerging technology with increasing adoption for commercial applications. However, its impact on the plant microbiome is not entirely clear. The assumption is that controlled conditions reduce the risk of introduction and spread of pathogens, human or plant. Here, we assessed the microbial flux through a commercially relevant CEA plant growth tower from culture-dependent and independent approaches. This allowed the relationship between two of the main entry points for microbes to be determined, the circulating water system and plant growth substrates, on two crop species systems, kale and lettuce. There was a clear distinction between the taxonomic compositions of bacteria in the water-associated and coir-associated compartments. Overall, water did not contribute the most abundant members of the microbiota on plants. Rainwater, used as a top-up source of water, was not the major source of sequenced microbes in either the circulating water system or in coir compartments. The main points of expansion of cultural microbes were in the irrigation tray system and the physical presence and growth of the crop plants. The effect of UV-C, typically used to treat water, and the LED lighting system were quantified for proxy pathogen strains.

Clostridioides difficile is a potentially harmful bacterium that can affect preterm infants more seriously than full-term infants, largely due to their immature immune systems and underdeveloped gut microbiota. Although colonization with C. difficile is often harmless in healthy babies, preterm infants are more likely to develop infections, which can lead to serious health problems. This review looks at how an immature immune system and an imbalanced gut microbiome increase the risk of C. difficile infection (CDI) in early life. To reduce this risk, researchers are exploring postbiotics-non-living bacterial products or byproducts-as a safer alternative to traditional treatments like antibiotics. Postbiotics can help by strengthening the gut barrier, reducing inflammation, and supporting the growth of beneficial bacteria. They are also considered safe for use in vulnerable populations, including infants. This review discusses the types of postbiotics, their functions, and how they may help prevent or manage CDI. It also highlights their potential for use in infant formula as a preventative strategy. Overall, postbiotics may offer a promising new way to protect preterm infants from C. difficile and support healthier immune and gut development.

The role of gut and vaginal microbiota has been examined as potential markers in the progression of cervical cancer and inspired heightened attention. We attempted to identify the current status, the influence of changing trends in the gut and vaginal microbiota, and their impact on cervical cancer. All publications were searched in online databases such as PubMed, Scopus, Medline, and Google Scholar using the keywords "cervical cancer," "vaginal microbiota," "gut microbiota," "dysbiosis," "cervical intraepithelial neoplasia," and "HPV." Growing evidence that gut microbiota dysbiosis is involved in many diseases has attracted many researchers. The vaginal microbiome is a micro-ecosystem complex that undergoes continuous fluctuations throughout a woman's life. Decrease in Lactobacilli spp. Levels can lead to an overgrowth of anaerobic bacteria, resulting in bacterial vaginosis that accounts for adverse health outcomes, including increased susceptibility to sexually transmitted infections, including human papillomavirus, and cervical intraepithelial neoplasia, leading to cervical cancer. Thus, dysbiosis, characterized by an imbalance of beneficial and harmful bacteria, can negatively affect health. Understanding the intricate interactions between the microbiota and cervical cancer can provide valuable insights into potential therapeutic strategies and the development of preventive measures.

Viral infections, including arboviruses such as chikungunya, zika, dengue, and mayaro fever, remain significant global health and economic challenges, fueled by the emergence and resurgence of mosquito-borne diseases. Natural products, especially plant-derived compounds, have been crucial in drug discovery and often serve as scaffolds for synthetic drug development. This study focused on modifying paulownin, an isolated lignan, through a Click reaction to incorporate 1,2,3-triazole and quinolinic ring frameworks. The resulting derivative 7 was evaluated for its in vitro antiviral activity against Alphavirus chikungunya (CHIKV). The paulownin derivative 7 did not exhibit cytotoxicity in Vero cells and demonstrated potent activity against CHIKV, with median effective concentration value of 9.05 µM and a selectivity index exceeding 16.8. Furthermore, compound 7 outperformed positive controls, being over 46 times more active against CHIKV. Cytopathic effect assays confirmed this anti-CHIKV activity. The virucidal assay indicated that the compound does not exert a direct effect on CHIKV particles before cell infection. RT-qPCR studies further demonstrated derivative 7 significantly reduces CHIKV replication. These findings highlight the paulownin derivative 7 as a promising and selective candidate for CHIKV treatment.

Drug repurposing, offers promising opportunities to address infections caused by multidrug-resistant bacteria. This study was to evaluate the bactericidal activity, anti-biofilm properties, and potential mechanisms of the antihistamine drug ebastine against Staphylococcus aureus. The minimum inhibitory concentrations of ebastine against standard and clinical S. aureus isolates were determined using the broth microdilution method. The MIC values ranged from 2 to 8 µg·mL-1, indicating good activity against clinical drug-resistant strains. Time-kill curve analyses revealed a dose-dependent bactericidal effect. Regarding anti-biofilm activity, ebastine significantly inhibited biofilm formation at higher concentrations and demonstrated a moderate ability to eradicate preformed biofilms. Mechanistic studies revealed that ebastine exerted the antimicrobial effects by causing disruption to bacterial membrane integrity and inducing reactive oxygen species generation. Furthermore, safety evaluations showed that ebastine exhibited limited toxicity to mammalian cells, with negligible hemolytic effects and good overall safety profiles. This study provided new insights into the potential applications of ebastine in the field of antimicrobial therapy, highlighting its promise as a non-traditional antibacterial agent.

Environmental microbes have been linked to both beneficial and harmful effects on the lungs in relation to asthma. The aim of our study was to characterize the bacterial microbiome in lung samples from a mouse model of asthma exposed to titanium dioxide (TiO2) particles, and the effect of OM-85 Broncho-Vaxom®, a bacterial lysate on lung microbiome in mice. The mice were divided randomly into four groups of 6-8 mice per group. To identify the microbial communities in lung samples the upper right lung of all groups, we amplified and sequenced the rRNA gene regions from bacterial DNA (16S). The amplified 16S region was sequenced using the Roche-454 Life Sciences Titanium pyrosequencing platform. In the OVA + TiO2 + OM-85 group, airway hyperresponsiveness and inflammatory cells in bronchoalveolar lavage fluid (BALF) decreased compared to the OVA + TiO2 group. Inflammatory cytokine levels were lower in the OVA + TiO2 + OM-85 group. Certain bacteria, and Collinsella aerofaciens, decreased in the OVA + TiO2 + OM-85 group, while Neisseria perflava and Fusobacterium periodonticum increased. Lactic acid bacteria groups decreased in the OVA + TiO2 + OM-85 group. TiO2 particles exposure changed lung microbial taxa, and modified by a bacterial lysate, suggesting that a probiotic can be helpful in reducing exacerbation of airway disease exposed to air pollutants.

Bacillus thuringiensis RZ2MS9, a plant growth-promoting rhizobacterium isolated from the rhizosphere of guarana plants, has shown significant growth enhancement in both soybean and maize crops. To explore its full potential, we investigated RZ2MS9's entomopathogenic properties against Lepidoptera and Coleoptera larvae in vitro, and against Hemiptera populations in both in vitro and field conditions. The strain was evaluated for insecticidal crystal proteins, which were found in cuboid and spherical forms. Comparative genomic analysis revealed that while RZ2MS9 did not share significant pesticidal protein genes with B. thuringiensis HD1, it has unique genes related to plant growth promotion and nutrient acquisition. RZ2MS9 also exhibited chitinolytic activity, linked to the presence of the chitosanase coding gene (chP). Under laboratory conditions, the larvae mortality under RZ2MS9 treatment was 90% for sugarcane borer (Diatraea saccharalis), 92.5% for old-world cotton bollworm (Helicoverpa armigera), 30% for Agrotis ipsilon, and 87.5% for Anthonomus grandis. In addition, RZ2MS9 caused severe wing deformities in 40% of Spodoptera frugiperda moths and repelled Piezodorus guildinii from its food source. In field trials, soybean plants inoculated with RZ2MS9 exhibited significative increased length. P. guildinii was more prevalent in the inoculated plants, while the incidence of Euchistus heros remained unchanged.

Arbuscular mycorrhizal fungi (AMF) are known to enhance the accumulation of bioactive compounds with medicinal properties in plants. However, the potential cytotoxic effects of extracts from mycorrhizal plants on peripheral blood mononuclear cells (PBMC) remain unexplored. Therefore, this study aimed to verify the cytotoxic potential of foliar extract from Hymenaea martiana Hayne seedlings, either associated or not associated with AMF on PBMC. A greenhouse experiment was conducted with two treatments: a control group (without AMF) and a group inoculated with Acaulospora longula Spain and N.C. Schenck. After 148 days, leaves were collected to prepare aqueous extracts, and cytotoxicity of the extracts was assessed using the MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide) assay. Additionally, the antioxidant potential and the content of soluble carbohydrates, flavonoids, flavonols, flavonones, dihydroflavonols, and saponins were assessed. Hymenaea martiana seedlings associated with A. longula exhibited a more than 50% increase in the accumulation of phenolic compounds compared to the control. However, no toxicity was detected for PBMC under any of the conditions evaluated. This study provides the first evidence of the effect of mycorrhizal plant extracts on human blood cells, highlighting their potential safety for medicinal and cosmetic applications.