Search Results (281)

Acacia mearnsii De Wild. has been introduced to over 150 countries for its economic value. However, it easily escapes from plantations and establishes monospecific stands across plains, hills, valleys, and riparian habitats, including protected areas such as national parks and forest reserves. Due to its negative ecological impact, A. mearnsii has been listed among the world’s 100 worst invasive alien species. This species exhibits rapid stem growth in its sapling stage and reaches reproductive maturity early. It produces a large quantity of long-lived seeds, establishing a substantial seed bank. A. mearnsii can grow in different environmental conditions and tolerates various adverse conditions, such as low temperatures and drought. Its invasive populations are unlikely to be seriously damaged by herbivores and pathogens. Additionally, A. mearnsii exhibits allelopathic activity, though its ecological significance remains unclear. These characteristics of A. mearnsii may contribute to its expansion in introduced ranges. The presence of A. mearnsii affects abiotic processes in ecosystems by reducing water availability, increasing the risk of soil erosion and flooding, altering soil chemical composition, and obstructing solar light irradiation. The invasion negatively affects biotic processes as well, reducing the diversity and abundance of native plants and arthropods, including protective species. Eradicating invasive populations of A. mearnsii requires an integrated, long-term management approach based on an understanding of its invasive mechanisms. Early detection of invasive populations and the promotion of public awareness about their impact are also important. More attention must be given to its invasive traits because it easily escapes from cultivation. Full article

Nosocomial infections caused by ESKAPE pathogens represent a significant burden to global health. These pathogens may exhibit multidrug resistance (MDR) mechanisms, of which mechanisms such as efflux pumps and biofilm formation are gaining significant importance. Multidrug resistance mechanisms in ESKAPE pathogens have led to an increase in the effective costs in health care and a higher risk of mortality in hospitalized patients. These pathogens utilize antimicrobial efflux pump mechanisms and bacterial biofilm-forming capabilities to escape the bactericidal action of antimicrobials. ESKAPE bacteria forming colonies demonstrate increased expression of efflux pump-encoding genes. Efflux pumps not only expel antimicrobial agents but also contribute to biofilm formation by bacteria through (1) transport of molecules and transcription factors involved in biofilm quorum sensing, (2) bacterial fimbriae structure transport for biofilm adhesion to surfaces, and (3) regulation of a transmembrane gradient to survive the difficult conditions of biofilm microenvironments. The synergistic role of these mechanisms complicates treatment outcomes. Given the mechanistic link between biofilms and efflux pumps, therapeutic strategies should focus on targeting anti-biofilm mechanisms alongside efflux pump inactivation with efflux pump inhibitors. This review explores the molecular interplay between efflux pumps and biofilm formation, emphasizing potential therapeutic strategies such as efflux pump inhibitors (EPIs) and biofilm-targeting agents. Full article

Recent outbreaks of highly pathogenic human RNA viruses from probable zoonotic origin have highlighted the relevance of epidemic preparedness as a society. However, research in vaccinology and virology, as well as epidemiologic surveillance, is often constrained by the biological risk that live virus experimentation entails. These also involve expensive costs, time-consuming procedures, and advanced personnel expertise, hampering market access for many drugs. Most of these drawbacks can be circumvented with the use of pseudotyped viruses, which are surrogate, non-pathogenic recombinant viral particles bearing the surface envelope protein of a virus of interest. Pseudotyped viruses significantly expand the research potential in virology, enabling the study of non-culturable or highly infectious pathogens in a safer environment. Most are derived from lentiviral vectors, which confer a series of advantages due to their superior efficiency. During the past decade, many studies employing pseudotyped viruses have evaluated the efficacy of vaccines or monoclonal antibodies for relevant pathogens such as HIV-1, Ebolavirus, Influenza virus, or SARS-CoV-2. In this review, we aim to provide an overview of the applications of pseudotyped viruses when evaluating the neutralization capacity of exposed individuals, or candidate vaccines and antivirals in both preclinical models and clinical trials, to further help develop effective countermeasures against emerging neutralization-escape phenotypes. Full article

Polyomaviruses are a family of small DNA viruses capable of establishing persistent infections, and they can pose significant pathogenic risks in immunocompromised hosts. While traditionally studied in the context of viral reactivation and immune suppression, recent evidence has highlighted the gut microbiota as a critical regulator of host immunity and viral pathogenesis. This review examines the complex interactions between polyomaviruses, the immune system, and intestinal microbiota, emphasizing the role of short-chain fatty acids (SCFAs) in modulating antiviral responses. We explore how dysbiosis may facilitate viral replication, reactivation, and immune escape and also consider how polyomavirus infection can, in turn, alter microbial composition. Particular attention is given to the Firmicutes/Bacteroidetes ratio as a potential biomarker of infection risk and immune status. Therapeutic strategies targeting the microbiota, including prebiotics, probiotics, and fecal microbiota transplantation (FMT), are discussed as innovative adjuncts to immune-based therapies. Understanding these tri-directional interactions may offer new avenues for mitigating disease severity and improving patient outcomes during viral reactivation. Full article

The non-traditional companion animal (NTCA) sector, particularly involving avian species, has significantly expanded in Italy, raising concerns over the spread of infectious diseases. These animals can harbor various pathogens and act as reservoirs, posing risks to native wildlife through legal or illegal trade, escapes, or intentional releases. However, the epidemiology of avian pathogens in NTCAs remains poorly understood and is typically investigated only in symptomatic individuals. In the present study, cloacal and choanal cleft swabs were collected from 319 ornamental and raptor birds across 19 families, pooled and tested for beak and feather disease virus (BFDV), avian polyomavirus (APV-1), psittacid herpesvirus 1 (PsHV-1), and avian metapneumovirus (aMPV). BFDV and APV-1 were detected in 13.79% and 2.19% of birds, respectively, with five co-infections. No cases of PsHV-1 or aMPV were found. Both viruses showed a higher prevalence than in previous Italian and most of international studies, with several non-psittacine species, including birds of prey, testing positive—some for the first time. Mixed-species settings and participation in public exhibitions were proven as significant infection risk factors. The study highlights the growing relevance of BFDV and APV-1 in non-commercial birds and recommends improved biosecurity and preventive screening to reduce disease spread and safeguard animal health. Full article

In 2022, consecutive sweeps of highly transmissible SARS-CoV-2 Omicron-derived lineages (B.1.1.529*) maintained viral transmission despite extensive antigen exposure from both vaccinations and infections. To better understand Omicron variant emergence in the context of the dynamic fitness landscape of 2022, we aimed to explore putative drivers behind SARS-CoV-2 lineage replacements. Variant fitness is determined through its ability to either outrun previously dominant lineages or more efficiently circumvent host immune responses to previous infections and vaccinations. By analyzing data collected through our local genomic surveillance program from Connecticut, USA, we compared emerging Omicron lineages’ growth rates, estimated infections, effective reproductive rates, average viral copy numbers, and likelihood for causing infections in recently vaccinated individuals. We find that newly emerging Omicron lineages outcompeted dominant lineages through a combination of enhanced viral shedding or advanced immune escape depending on the population-level exposure state. This analysis integrates individual-level sequencing data with demographic, vaccination, laboratory, and epidemiological data and provides further insights into host–pathogen dynamics beyond public aggregate data. Full article

Arundo donax L. has been introduced in markets worldwide due to its economic value. However, it is listed in the world’s 100 worst alien invasive species because it easily escapes from cultivation, and forms dense monospecific stands in riparian areas, agricultural areas, and grassland areas along roadsides, including in protected areas. This species grows rapidly and produces large amounts of biomass due to its high photosynthetic ability. It spreads asexually through ramets, in addition to stem and rhizome fragments. Wildfires, flooding, and human activity promote its distribution and domination. It can adapt to various habitats and tolerate various adverse environmental conditions, such as cold temperatures, drought, flooding, and high salinity. A. donax exhibits defense mechanisms against biotic stressors, including herbivores and pathogens. It produces indole alkaloids, such as bufotenidine and gramine, as well as other alkaloids that are toxic to herbivorous mammals, insects, parasitic nematodes, and pathogenic fungi and oomycetes. A. donax accumulates high concentrations of phytoliths, which also protect against pathogen infection and herbivory. Only a few herbivores and pathogens have been reported to significantly damage A. donax growth and populations. Additionally, A. donax exhibits allelopathic activity against competing plant species, though the allelochemicals involved have yet to be identified. These characteristics may contribute to its infestation, survival, and population expansion in new habitats as an invasive plant species. Dense monospecific stands of A. donax alter ecosystem structures and functions. These stands impact abiotic processes in ecosystems by reducing water availability, and increasing the risk of erosion, flooding, and intense fires. The stands also negatively affect biotic processes by reducing plant diversity and richness, as well as the fitness of habitats for invertebrates and vertebrates. Eradicating A. donax from a habitat requires an ongoing, long-term integrated management approach based on an understanding of its invasive mechanisms. Human activity has also contributed to the spread of A. donax populations. There is an urgent need to address its invasive traits. This is the first review focusing on the invasive mechanisms of this plant in terms of adaptation to abiotic and biotic stressors, particularly physiological adaptation. Full article

Liver cancer has high incidence and mortality rates worldwide, with hepatocellular carcinoma (HCC) being the main histological subtype, accounting for 90% of primary liver cancers. The high mutation rate of viruses combined with endoplasmic reticulum stress may lead to the occurrence of cancer. Hepatitis B virus (HBV) infection is one of the most important pathogenic factors of HCC. The carcinogenic mechanisms of HBV have been widely studied. Among these mechanisms, immune escape and vaccine escape caused by mutations in the HBV S gene have been reported in numerous studies of patients with chronic hepatitis B. In addition, pre-S1/S2 mutations and surface protein truncation mutations may activate multiple signaling pathways. This activation leads to the abnormal proliferation and differentiation of hepatocytes, thereby contributing to the development of HCC. This review aims to integrate the existing literature, summarize the common mutations in the HBV S gene region, and explore the related pathogenic mechanisms. Full article

Klebsiella pneumoniae, a zoonotic pathogen of global concern, poses significant threats to both veterinary and public health. Here, a comparative study characterized 14 clinical isolates (7 avian-derived, 7 human-derived) from Jiangsu, China, through integrated genomic and phenotypic analyses. Firstly, multilocus sequence typing (MLST) revealed distinct epidemiological patterns: the same ST type in avian isolates was circulating between different species and different regions, whereas it was not found in human isolates. In addition, hypervirulent Klebsiella pneumoniae (hvKP) phenotypes confirmed by string test were exclusive to two human isolates (KP15, KP20). Secondly, biofilm detection demonstrated 78.6% (11/14) of isolates possessed biofilm-forming capacity, with cellulose but not curli as the predominant matrix component. Human-derived KP15 and KP20 had the strongest biofilm formation ability in all isolates. Antimicrobial susceptibility profiling identified serious multidrug resistance in both avian and human isolates. Virulence gene analysis revealed striking disparities, with human isolates harboring 10–20 virulence factors (median 15) versus 6–7 (median 6.5) in avian counterparts. Finally, functional pathogenesis assessments demonstrated human-derived strains exhibited stronger epithelial cell adhesion (2-fold higher) and invasion (1.97-fold higher) in Calu-3 cell models and paradoxically showed reduced macrophage phagocytosis (2.85-fold lower at 2 h) for immune escape. In vivo models confirmed dose-dependent mortality, with human isolates demonstrating higher lethality in both Galleria mellonella and mice. Virulence gene burden positively correlated with mortality outcomes. These findings delineate critical host adaptation differences in Klebsiella pneumoniae populations and provide empirical evidence for pathogen transmission dynamics at the human-animal interface. Full article

Stress granules (SG), dynamic cytoplasmic condensates formed via liquid-liquid phase separation (LLPS), serve as a critical hub for cellular stress adaptation and antiviral defense. By halting non-essential translation and sequestering viral RNA, SG restrict viral replication through multiple mechanisms, including PKR-eIF2α signaling, recruitment of antiviral proteins, and spatial isolation of viral components. However, viruses have evolved sophisticated strategies to subvert SG-mediated defenses, including proteolytic cleavage of SG nucleators, sequestration of core proteins into viral replication complexes, and modulation of stress-responsive pathways. This review highlights the dual roles of SG as both antiviral sentinels and targets of viral manipulation, emphasizing their interplay with innate immunity, autophagy, and apoptosis. Furthermore, viruses exploit SG heterogeneity and crosstalk with RNA granules like processing bodies (P-bodies, PB) to evade host defenses, while viral inclusion bodies (IBs) recruit SG components to create proviral microenvironments. Future research directions include elucidating spatiotemporal SG dynamics in vivo, dissecting compositional heterogeneity, and leveraging advanced technologies to unravel context-specific host-pathogen conflicts. This review about viruses and SG formation helps better understand the virus-host interaction and game process to develop new drug targets. Understanding these mechanisms not only advances virology but also informs innovative strategies to address immune escape mechanisms in viral infections. Full article

Public health crises triggered by viral infections pose severe threats to individual health and disrupt global socioeconomic systems. Against the backdrop of global pandemics caused by highly infectious diseases such as COVID-19 and Ebola virus disease (EVD), the development of innovative prevention and treatment strategies has become a strategic priority in the field of biomedicine. Neutralizing antibodies, as biological agents, are increasingly recognized for their potential in infectious disease control. Among these, nanobodies (Nbs) derived from camelid heavy-chain antibodies exhibit remarkable technical advantages due to their unique structural features. Compared to traditional neutralizing antibodies, nanobodies offer significant cost-effectiveness in production and enable versatile administration routes (e.g., subcutaneous injection, oral delivery, or aerosol inhalation), making them particularly suitable for respiratory infection control and resource-limited settings. Furthermore, engineered modification strategies—including multivalent constructs, multi-epitope recognition designs, and fragment crystallizable (Fc) domain fusion—effectively enhance their neutralizing activity and suppress viral immune escape mechanisms. Breakthroughs have been achieved in combating pathogens such as the Ebola virus and SARS-CoV-2, with mechanisms involving the blockade of virus–host interactions, induction of viral particle disintegration, and enhancement of immune responses. This review comprehensively discusses the structural characteristics, high-throughput screening technologies, and engineering strategies of nanobodies, providing theoretical foundations for the development of novel antiviral therapeutics. These advances hold strategic significance for addressing emerging and re-emerging infectious diseases. Full article

Streptococcus agalactiae (GBS) is a major pathogen causing mastitis in dairy cows while causing oxidative stress. Matrine is an alkaloid compound extracted from the roots of Sophora flavescens, a plant used in traditional Chinese medicine. It possesses antioxidant, immunomodulatory, anti-inflammatory, and pro-apoptotic properties. The aim of this study was to investigate the regulatory effects of matrine on the virulence of the ATCC strain (ATCC13813) and clinical GBS strains by transcriptome analysis and qRT-PCR validation. The results showed that the ABC transporter, peptidoglycan biosynthesis, and quorum-sensing pathways were significantly altered in ATCC (4 mg/mL) and GBS (12 mg/mL) strains after matrine treatment at MIC concentrations. Additionally, genes related to invasion and immune escape, including CylE, CAMP, ScpB, and CpsA, and genes related to the expression of adhesion and virulence factors, such as Bac, Lmb, PI2a, and PI2b, were significantly downregulated (p < 0.05). Overall, these data suggest that matrine effectively inhibits the virulence genes of GBS, thereby reducing immune evasion and infection by decreasing the synthesis of capsular polysaccharides and host cell adhesion. Full article

In the past 5 years, the COVID-19 pandemic has experienced frequently changing variants contextualizing immune evasion. The emergence of Omicron with >30–50 mutations on the spike gene has shown a sharp divergence from its relative VOCs, such as WT, Alpha, Beta, Gamma, and Delta. The requisition of prime boosting was essential within 3–6 months to improve the Nab response that had been not lasted for longer. Omicron subvariant BA.1.1 was less transmissible, but with an extra nine mutations in next variant BA.2 made it more transmissible. This remarkable heterogeneity was reported in ORF1ab or TRS sites, ORF7a, and 10 regions in the genomic sequences of Omicron BA.2 and its evolving subvariants BA.4.6, BF.7, BQ.2, BF. 7, BA.2.75.2, and BA.5 (BQ.1 and BQ.1.1). The mutational stability of subvariants XBB, XBB 1, XBB 1.5, and XBB 1.6 conferred a similar affinity towards ACE-2. This phenomenon has been reported in breakthrough infections and after booster vaccinations producing hybrid immunity. The reduced pathogenic nature of Omicron has implicated its adaptation either through immunocompromised individuals or other animal hosts. The binding capacity of RBD and ACE-2, including the proteolytic priming via TMPRSS2, reveals its (in-vitro) transmissibility behavior. RBD mutations signify transmissibility, S1/S2 enhances virulence, while S2 infers the effective immunogenic response. Initial mutations D614G, E484A, N501Y, Q493K, K417N, S477N, Y505H, and G496S were found to increase the Ab escape. Some mutations such as, R346K, L452R, and F486Vwere seen delivering immune pressure. HR2 region (S2) displayed mutations R436S, K444T, F486S, and D1199N with altered spike positions. Later on, the booster dose or breakthrough infections contributed to elevating the immune profile. Several other mutations in BA.1.1-N460K, R346T, K444T, and BA.2.75.2-F486S have also conferred the neutralization resistance. The least studied T-cell response in SARS-CoV-2 affects HLA- TCR interactions, thus, it plays a role in limiting the virus clearance. Antigenic cartographic analysis has also shown Omicron’s drift from its predecessor variants. The rapidly evolving SARS-CoV-2 variants and subvariants have driven the population-based immunity escape in fully immunized individuals within short period. This could be an indication that Omicron is heading towards endemicity and may evolve in future with subvariants could lead to outbreaks, which requires regular surveillance. Full article

Tomato brown rugose fruit virus (ToBRFV) is a recently emerged viral pathogen in the Tobamovirus genus first observed in 2014 in the Middle East that has since spread worldwide, causing significant losses in greenhouse tomato production. ToBRFV is easily mechanically transmitted and can escape the durable Tm-2² resistance gene, facilitating its global spread. Seed companies have identified novel sources of resistance and introduced these resistance traits into commercial cultivars. The identity, number, and mechanisms of these putative novel resistance genes are largely unknown but could be exerting selective pressures on ToBRFV. Here, we report 15 new ToBRFV genomic sequences from Canadian greenhouse production systems in susceptible and novel resistant or tolerant cultivars collected since 2023. We combined these sequences with five other Canadian ToBRFV genomes previously deposited in Genbank and a further five consensus sequences derived from metagenomic-based wastewater monitoring sequence data and conducted phylogenetic analysis. Most Canadian sequences grouped together when compared with 332 publicly available international sequences, but several isolates appeared distantly related, suggesting multiple introductions to Canadian production systems. High sequence identity between samples suggest movement of ToBRFV between independent greenhouses, highlighting areas where biosecurity can be improved. Several novel non-synonymous polymorphisms identified in the p126 and movement protein (MP) open reading frames (ORFs) were unique to Canadian sequences and associated with infection of novel resistant tomato cultivars. Many polymorphisms in the p126 ORF are located in a region of the protein associated with Tm-1 resistance-breaking isolates of tomato mosaic virus and ToBRFV, but have not been previously reported. Four novel polymorphisms in MP were also identified and do not appear to be associated with sites previously identified as interacting with Tm-2² and could be related to other unknown resistance genes. Together, these results confirm the difficulties in preventing the transmission of ToBRFV, identify putative adaptations to novel and existing resistance genes, and emphasize the urgent need for the cloning and characterization of these new sources of resistance to ToBRFV. Full article

Plant-phyllosphere feedback (PPF) is an ecological process in which phyllosphere microbiota, originating from plant litter, are transmitted via aerosols and subsequently influence the growth of conspecific or heterospecific plants. However, the cross-species generality of this mechanism and its role in invasive plant success remain to be fully elucidated. This study systematically examined PPF effects using three invasive/native congeneric plant pairs from distinct families (Phytolaccaceae, Asteraceae, and Amaranthaceae) in Jiangxi Province, China. Key findings include the following: (1) Wide conspecific negative feedback across families, with four of six species exhibiting 6.2–12.7% biomass reduction under their own litter treatments (p < 0.05). (2) Comparable feedback intensity between invasive and native species, as indicated by average pairwise indices (invasive I = −0.05 vs. native I = −0.04; p = 0.15). Notably, the invasive species Phytolacca americana uniquely showed a positive biomass response (+7.1%), though underlying mechanisms (phytochemical or microbial) were not investigated. (3) Lack of correlation between PPF strength and plant functional traits or phylogenetic distance, as indicated by Mantel tests (p > 0.8), in contrast to the trait/phylogeny associations commonly observed in soil feedback systems. This study provided the first evidence of PPF universality across multiple plant families—previously documented only within Asteraceae—and highlights the potential microbial-mediated advantages in plant invasions. Future research should integrate spatiotemporal metagenomic and metabolomic approaches to decipher the dynamic pathogen/microbe networks and their phytochemical interactions. Full article