ACC deaminase producing plant growth promoting bacteria have emerged as an effective biological solution to alleviate ethylene inhibition in plants exposed to stress. Central to stress mitigation, 1-aminocyclopropane-1-carboxylate (ACC) deaminase (AcdS) cleaves ACC to α-ketobutyrate and ammonia lowering stress-ethylene and sustaining growth. This review emphasis on advances in the structure, function, regulation of ACC deaminase and enzymatic control of ACC under diverse environmental conditions. It provides an insight of how ACC is released by roots, transported in the rhizosphere and taken up by beneficial bacteria. The AcdS activity influences auxin-ethylene balance to support better root growth and stress tolerance. ACC deaminase-producing PGPB belonging to genera such as Enterobacter, Bacillus, Pseudomonas, Lysinibacillus, Methylobacterium, Achromobacter, and Halobacillus have been widely reported to alleviate abiotic stresses including salinity, drought, temperature extremes, and heavy metal toxicity in major crops like wheat, rice, maize, and tomato. Future prospects include enhancing AcdS efficiency and stability through advanced molecular approaches and developing robust bioformulations for scalable field distribution in stress-resilient agriculture. The present review integrates structural, mechanistic and translational insights to guide scalable deployment of ACC deaminase producing PGPB for stress management.

Patagonian fungi are an underexplored source of secondary metabolites with promising antimicrobial potential, a topic of growing relevance given the global spread of antibiotic resistance. In this study, we evaluated the antibacterial activity of 85 fungal isolates from Ascomycota, Basidiomycota, and Mucoromycota; 49 fungal conditioned media displayed inhibition against both Gram-positive and Gram-negative bacteria in a 96-well OD₆₀₀ microplate assay. Staphylococcus aureus, Bacillus subtilis, and Lysinibacillus sphaericus were the most sensitive Gram-positive strains, while Klebsiella pneumoniae showed the highest susceptibility among Gram-negative species. Complete inhibition of S. aureus was achieved in the conditioned-media assay by Arthrinium arundinis, Cladosporium sp., Graphilbum sp. 2, and Postia balsamea, with Graphilbum representing a previously unreported antimicrobial genus. In the conditioned-media microplate assay, potent antibacterial activity (> 99.5%) against all 5 tested bacterial strains was recorded for Allantophomopsis sp., Aureobasidium sp., Coniochaeta sp., Graphilbum sp. 2, and Mucor pyriformis, most of which have not been previously associated with antibacterial activity against Bacillus or Klebsiella genus. Marked inhibition of S. aureus and K. pneumoniae laboratory strains was observed for Arachnopeziza aurelia, Coprinellus sp., and Poria sp. Remarkably, Umbelopsis (Mucoromycota) inhibited all bacteria strains tested in the conditioned-media assay, revealing previously unreported antibacterial activity for this genus. Several extracts retained measurable but variable antibacterial activity in disk-diffusion assays producing inhibition zones against selected bacterial strains. Chemical profiling of active extracts revealed cyclic dipeptides (diketopiperazines) as recurrent metabolites and a unique family of unknown compounds exclusively found in Graphilbum sp. 2, representing its first metabolomic characterization. Overall, these results identify Patagonian fungi as a valuable reservoir of bioactive metabolites with potential as new natural antimicrobial agents.

Multidrug-resistant (MDR) nosocomial pathogens represent a critical global health challenge, necessitating the development of novel multitarget antibacterial agents. In this study, a new series of aryl-urea derivatives incorporating uracil and perfluorophenyl moieties were synthesized and structurally characterized using NMR, IR, and elemental analyses. Among the synthesized compounds, perfluorophenyl-based derivatives (compounds 4 and 5) exhibited potent antibacterial activity against vancomycin-resistant Enterococcus faecalis and carbapenem-resistant Acinetobacter baumannii, with low minimum inhibitory concentration (MIC) values. Mechanistic investigations revealed that these compounds significantly inhibited biofilm formation (> 50%), approaching the efficacy of ciprofloxacin, highlighting their strong anti-virulence potential. Notably, both compounds induced a marked increase in intracellular reactive oxygen species (ROS), suggesting oxidative stress-mediated bacterial killing. Furthermore, molecular analyses demonstrated substantial down-regulation of DNA gyrase (gyrA) expression, alongside significant suppression of key virulence genes, including OmpA in A. baumannii and GelE in E. faecalis. Importantly, the integration of oxidative stress induction, DNA topology disruption, and virulence attenuation establishes a coordinated multitarget mechanism underlying the antibacterial efficacy of these compounds. Collectively, this study introduces perfluorophenyl aryl-urea derivatives as promising next-generation antibacterial candidates with dual bactericidal and antivirulence activities, offering a strategic advantage for combating MDR nosocomial infections and warranting further preclinical development.

Autism spectrum disorder (ASD) is a common childhood neurodevelopmental disorder. While many medicines offer therapeutic benefits, they are often associated with adverse side effects. Probiotics, however, present a safer interventional strategy. In this study, we investigated the effects of three probiotic agents: a multi-strain Bacillus formulation, a multi-strain Lactobacillus formulation, and the yeast Saccharomyces boulardii, in a rat model of ASD. The study included a total of 6 groups: a control group with no treatment, an ASD model group induced by valproate (VPA), and three probiotic intervention groups. The results showed that multi-strain Bacillus probiotics treatment was the most significant in alleviating VPA-induced autism in rats. Multi-strain Bacillus probiotics supplementation exerted a significant effect on stereotypic behaviors in ASD rats. Further studies found that multi-strain Bacillus probiotics alleviated ASD symptoms by reducing gut inflammation, optimizing gut microbiota composition and regulating short-chain fatty acid levels. Overall, the study evidence suggested that multi-strain Bacillus probiotics was the most effective for the treatment of VPA-induced ASD rat model.

To maintain diverse communities under changing environmental conditions, species must be able to concentrate density feedback within species compared to between species. Density feedback can occur via multiple mechanisms, including predator partitioning, and is often mediated by the physical environment. If species respond differently to the environment (e.g. susceptibility to predators changes under different conditions) then environmental fluctuations can provide the necessary separation of density feedback to promote coexistence. Additionally, directional change in environmental conditions (as with climate change) can yield overall shifts in community composition. We assess possible pathways that a fungal-like parasite (Saprolegnia spp.) could modify these effects in a community of Hydrobiosidae caddisflies. We exposed caddisfly egg masses from four species to four controlled temperature regimes in the laboratory and determined mortality from infection. Saprolegnia spp. infection in caddisfly egg masses is species specific, a signature for predator partitioning which can influence coexistence. The caddisfly species also differ in how temperature alters their infection rates, with dramatic shifts in relative infection rates depending on the duration and timing of periods of high temperature. Our findings suggest that Saprolegnia spp. infection could limit dominant species, shift community composition, and help stabilise coexistence under fluctuating temperatures. While we show key conditions of coexistence are met, quantifying the effect of these temperature-mediated infection rates would require measuring the extent to which they modify density-dependent feedback.

The microgravity, radiation, and high-stress environment of space present unique challenges to astronauts' physical and mental health. In this environment, interactions between the host and pathogens are altered, thereby increasing astronauts' risk of endogenous viral infections. Notably, viral shedding detected during spaceflight does not necessarily indicate clinically significant disease, and the distinction between molecular reactivation, productive viral replication, and symptomatic infection must be carefully considered. This review aims to ensure mission success and enhance space biocapacity and biodefence by summarizing case studies and reactivation mechanisms of endogenous latent herpesviruses, the latest prevention and control strategies, and the challenges posed by host variability and antiviral efficacy in the space environment.

Despite extensive efforts by scientists, academic institutions, and pharmaceutical companies, a safe and effective HIV/AIDS vaccine remains elusive. Most HIV-1 envelope peptide vaccine strategies have concentrated on Gp120, gp140, or gp160. HIV-1 Env trimer binding to the CD4-receptor initiates structural changes promoting the envelope's transition from a closed to an open state via an intermediate step. Broadly neutralizing antibodies target the state-1 Env conformation, while less effective antibodies typically recognize open states. However, due to virus variability, an optimal vaccine has not yet been successfully developed. In this study, focusing on the pivotal role of Gp41 in various vaccine strategies, a very large sequence dataset was utilized. These sequences were obtained from drug-naïve individuals or those undergoing antiretroviral therapy (ART). Gp41 amino acid variability was characterized genetically using a starting pool dataset of 24,505 full-length Env sequences from HIV-1 Subtype-B infected individuals. The dataset underwent hydropathy analysis, genetic distance evaluation, non-synonymous/synonymous substitution rate estimation, Shannon-Entropy calculation, and N-linked glycosylation (NLG) analysis. Similar variability between viral sequences retrieved from drug-naïve and antiretroviral-treated individuals was observed. In our dataset, ART selection pressures observed at gp41 level are minimal: 7 positions with dN/dS > 1, significant increases in entropy values, and a comparable value of glycosylation sites were highlighted. This study reinforces the importance of identifying specific single sensitizing mutations in HIV control. Gp41 remains an important vaccine target for understanding virus-host immunological interactions. Further analyses may reveal specific mechanisms related to host antiviral responses and viral regions with strong masking activity.

Microbial lipases are versatile biocatalysts with wide industrial relevance; however, systematic integration of media optimization, kinetic modelling, bioreactor validation, and downstream processing remains limited for Pseudomonas aeruginosa ATCC 9027. This study evaluates the lipase production potential of P. aeruginosa ATCC 9027 through media optimization, kinetic analysis, bioreactor validation, partial purification, and preliminary cost assessment. Lipase production was optimized using Response Surface Methodology (RSM), focusing on the combined influence of olive oil and dextrose. Biomass growth, product formation, and substrate utilisation kinetics were analysed using unstructured models. Batch fermentation was validated in a 1.5L stirred-tank bioreactor and partial purification was performed. A laboratory-scale cost assessment was performed based on raw materials, equipment, and energy consumption. Optimized conditions yielded a maximum lipase activity of 0.48 U/mL (by titrimetric assay). Kinetic analysis showed that biomass growth was best described by the Logistic model (µmax = 0.19h⁻¹), while substrate consumption followed a modified Luedeking-Piret relationship, indicating growth-associated utilisation. Partial purification resulted in a 2.6-fold increase in purity, with specific activity improving from 86 to 223.10 U/mg (by spectrophotometric assay). Bioreactor studies confirmed the reproducibility of model-predicted conditions. Cost assessment provided a comparative framework for identifying major cost contributors at the laboratory scale. The study demonstrates that P. aeruginosa ATCC 9027 is a promising lipase producer and highlights the importance of integrating kinetic understanding, bioreactor validation, and downstream considerations for future scale-up and techno-economic evaluation.