Search Results (36)

The fungal pathogen Candida albicans coordinated metabolism, organelle homeostasis, and stress responses for adapting to diverse host environments and maintaining virulence. While transcriptional control of these processes has been extensively studied, the contribution of post-transcriptional regulation remains incompletely understood. Here, we identify the P-body component Lsm1 as a critical factor of metabolic adaptation, mitochondrial homeostasis, and pathogenicity in C. albicans. Transcriptomic analysis revealed that loss of Lsm1 causes global transcriptional imbalance, leading to dysfunction of amino acid metabolism, mitochondrial function, endocytic trafficking, and autophagy processes. This dysfunction is accompanied by diminished TORC1 activity. Due to the aberrant TORC1 regulation caused by loss of Lsm1, ATG mRNA stability and autophagy flux was impaired under nutrient-rich condition and nitrogen starvation condition. In this context, the lsm1Δ/Δ cells established an adaptive metabolic and redox state characterized by altered NAD⁺/NADH and NADP⁺/NADPH balance, and enhanced antioxidant capacity. Moreover, the lsm1Δ/Δ cells displayed the defects in hyphal development, biofilm formation, and host cell interaction, and exhibited the attenuated virulence in a murine infection model. Together, our findings revealed that Lsm1-mediated post-transcriptional regulation is associated with the maintenance of amino acid metabolism, mitochondrial function, and TORC1 activity to fungal virulence, revealing a potential therapeutic target for C. albicans infections. Full article

Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) poses a serious threat to the swine industry in China. As a major pig-producing province, Shandong requires continuous epidemiological monitoring of PRRSV. To elucidate the molecular epidemiology of the virus, 1621 clinical samples were collected from suspected cases across different regions of Shandong Province between 2023 and 2025, primarily from Tai’an, Linyi, Jining, and Liaocheng. RT-qPCR detection showed that the positive rate for PRRSV-2 was 20.05% (325/1621). Genetic analysis based on ORF5 and NSP2 genes indicated that Sublineage L1C (NADC30-like) was the dominant strain for 38.38% of ORF5 gene and 72.73% of NSP2 sequencing results. This was followed by Sublineage L8E and L1A and L5A strains. Key virulence-related mutations were identified at residues R13 and R151 in the GP5 protein, which are associated with enhanced pathogenicity. Additionally, variations in neutralizing epitope and the number of N-glycosylation sites (ranging from 2 to 5 per strain) suggested potential immune evasion. Notably, 26.79% (15/56) of sequenced samples showed discordant ORF5 and NSP2 genotyping results, indicating widespread recombination among PRRSV strains in Shandong Province. These finding demonstrated that the genetic diversity, high recombination frequency, and key amino acid variations in circulating PRRSV strains collectively undermine vaccine effectiveness. This study highlights the need to optimize vaccination strategies, enhance biosecurity measures, and implement effective disease control and elimination programs to reduce the impact of PRRSV in Shandong Province. Full article

In countries where Dengue virus is endemic, the occurrence of outbreaks and epidemic events is strongly associated with viral genomic evolution. In addition, the introduction of a new agent, such as Zika virus, in a naive population and its concomitant circulation may increase mutations and virulence. This study aimed to characterize the molecular patterns and circulation of Zika and Dengue viruses inland of midwestern Brazil. Samples from reported cases of zika and dengue fever were subjected to molecular and phylogenetic analyses. Partial genomes of these viruses were recovered and characterized from six samples. Phylogenetic analysis revealed that the Zika virus clustered within the American strain of Asian/American lineage and Dengue virus grouped within the Brazilian lineage (BR04) of serotype 2 from the Asian/American genotype. Amino acid substitutions, and consequently nonsynonymous mutations, were identified in the RdRp domain of the NS5 protein coding region in the recovered genomes from both viruses. These findings highlight the importance of molecular epidemiological surveillance, especially in endemic regions with cocirculation and substantial epidemic risk. Ongoing monitoring efforts are crucial to better understand viral evolution and its potential impact on future outbreaks and epidemic dynamics. Full article

Nocardia seriolae (N. seriolae) is a significant bacterial pathogen in global aquaculture, causing substantial economic losses. Live-attenuated vaccines represent a promising control strategy, but their molecular mechanisms remain poorly understood. This study employed a quantitative proteomic approach to compare the proteomic profiles of a virulent wild-type strain (F1) and an attenuated vaccine strain (F110) of N. seriolae. Using a data-independent acquisition (DIA)-based LC-MS/MS analysis, we identified 4516 proteins, with 540 showing significant differential expression (311 upregulated, 229 downregulated). Bioinformatic analysis revealed that upregulated proteins in F110 were primarily involved in metabolic processes, including phosphatidate cytidylyltransferase and various enzymes related to amino acid and nucleotide metabolism. Conversely, downregulated proteins were enriched in virulence-associated functions, including HtpX and MFS transporter permease. These findings suggest that attenuation involves a complex reprogramming of metabolic pathways coupled with a reduction in key virulence factors, providing insights into the potential molecular basis of vaccine development and potential targets for novel therapeutic strategies. Full article

Filoviruses are among the most lethal viral human pathogens known, with significant relevance to public health, yet their evolutionary history remains poorly resolved. This study applied a multiprotein molecular phylogenetic approach to investigate the evolutionary and temporal dynamics of the family Filoviridae. Amino acid sequences from the proteome and seven individual proteins (NP, VP35, VP40, GP, VP30, VP24, L) were analyzed using MEGA 12, with RelTime inference anchored on uniform calibrations, and integration of epidemiological data (cases, fatalities, case fatality). The phylogenetic reconstructions revealed robust topologies for most proteins, though selective pressures on GP, VP30 and VP40 generated more variable patterns. Temporal inferences supported the classification of filoviruses into three groups: an ancestral lineage (>1 MYA, fish- and reptile-associated), an intermediate lineage (BCE–1 MYA, bat-associated), and a contemporary lineage (CE, ebolaviruses and marburgviruses). VP30 and VP40 showed consistent associations with epidemiological outcomes in Orthoebolavirus zairense, suggesting their interplay may underlie enhanced dispersal and virulence. Contrariwise, Orthoebolavirus restonense emerged as a natural counterpoint for comparison with other potential human pathogenic filoviruses. Taken together, these findings highlight that filoviral evolution is intrinsically linked not only to viral biology but also to the ecology and history of their hosts. Full article

 Porcine epidemic diarrhea virus (PEDV) continues to circulate globally, causing substantial economic losses to the swine industry. Historically, PEDV strains are classified into the classical G1, epidemic G2, and S-INDEL genotypes. Among these genotypes, the highly virulent and prevalent G2 genotype has been extensively studied. However, recent clinical outbreaks in China necessitate a reevaluation of the epidemiological and evolutionary dynamics of circulating strains. This study analyzed 37 newly sequenced S genes and public sequences to characterize the genetic variations of S-INDEL strains. Our analysis revealed that S-INDEL strains are endemic throughout China, with a phylogenetic analysis identifying two distinct clades: clade 1, comprising early endemic strains, and clade 2, representing a recently dominant, geographically restricted lineage in China. While inter-genotypic recombination has been documented, our findings also demonstrate that intra-genotypic and intra-clade recombination events contributed significantly to the emergence of clade 2, distinguishing its evolutionary pattern from clade 1. A comparative analysis identified 22 clade-specific amino acid changes, 11 of which occurred in the D0 domain. Notably, mutations at positively selected sites—113 and 114 within the D0 domain, a domain associated with pathogenicity—were specific to clade 2. A phylodynamic analysis indicated Germany as the epicenter of S-INDEL dispersal, with China acting as a sink population characterized by localized transmission networks and frequent recombination events. These results demonstrate that contemporary S-INDEL strains, specifically clade 2, exhibit unique recombination patterns and mutations potentially impacting virulence. Continuous surveillance is essential to assess the pathogenic potential of these evolving recombinant variants and the efficacy of vaccines against them.  Full article

Necrotic enteritis (NE), caused by pathogenic Clostridium perfringens, poses a significant threat to global poultry health, with estimated annual losses exceeding USD 6 billion. The rising incidence of NE has been associated with the reduced use of antibiotic growth promoters, underscoring the urgent need for alternative control measures such as vaccination. Collagen adhesin protein (CNA), a key virulence factor in NE pathogenesis, represents a promising vaccine target. The US Food and Drug Administration has begun phasing out animal testing requirements for biologics and monoclonal antibody drugs. In this study, a computational multi-epitope vaccine (MEV) targeting CNA was designed by integrating predicted Cluster of Differentiation (CD)4⁺ helper T lymphocyte (Th), CD8⁺ cytotoxic T lymphocyte (CTL), and B-cell epitopes. Bioinformatics tools were used to identify immunogenic, antigenic, and non-allergenic epitopes assembled into a 115-amino-acid peptide vaccine construct. The candidate demonstrated strong stability and solubility. In silico immune simulation predicted robust immune responses, including elevated IgG and IgM antibody levels, plasma cell proliferation, Th memory formation, and CTL activation, comparable to responses elicited by a full-length CNA. These findings support the potential of the designed peptide as one of the multiple effective NE vaccine components, offering a promising alternative to antibiotic-based approaches in poultry disease management. Full article

Neonatal Meningitis-causing Escherichia coli (NMEC) is the leading cause of neonatal meningitis and exhibits remarkable adaptability to diverse host environments. Understanding its transcriptional responses across different host niches is crucial for deciphering pathogenesis and identifying potential therapeutic targets. We performed a comparative transcriptomic analysis of NMEC RS218, the prototype strain of NMEC, under four distinct host-mimicking conditions: colonic fluid (CF), serum (S), human brain endothelial cells (HBECs), and cerebrospinal fluid (CSF). Differential gene expression analysis was conducted to assess metabolic shifts, virulence factor regulation, and niche-specific adaptation strategies, in which RS218 demonstrated niche-specific transcriptional reprogramming. In CF, genes associated with biofilm formation, motility, efflux pumps, and cell division regulation were upregulated, aiding gut colonization. The serum environment triggered the expression of siderophore-mediated iron acquisition, enterobactin biosynthesis, and heme utilization genes, facilitating immune evasion and bacterial persistence. In HBECs, NMEC upregulated genes linked to nucleoside metabolism, membrane remodeling, pilus organization, and blood–brain barrier (BBB) traversal. In CSF, genes related to oxidative stress resistance, chemotaxis, DNA repair, biofilm formation, and amino acid biosynthesis were enriched, reflecting NMEC’s adaptive mechanisms for survival under nutrient-depleted conditions. Energy-intensive pathways were consistently downregulated across all niches, highlighting the need for an energy conservation strategy. This study provides novel insights into NMEC’s adaptive strategies across different host environments, emphasizing its metabolic flexibility, virulence regulation, and immune evasion mechanisms, offering potential targets for therapeutic intervention. Full article

Marek’s disease (MD) is a highly contagious and oncogenic viral disease of poultry, causing significant economic losses due to mortality and reduced performance. The rapid evolution of Marek’s disease virus (MDV) has been reported in poultry farms, often overcoming vaccination and leading to disease outbreaks. This study aimed to detect and molecularly characterize circulating MDV strains in Tanzania, with a focus on their genetic relationship with the vaccine strains currently in use (HVT and CVI988). Samples were collected from six livestock representative zones in Tanzania (Central, Eastern, Southern, Southern Highlands, Lake, and Northern Zone) and analyzed using polymerase chain reaction (PCR) and sequencing of key oncogenic genes (meq, pp38, and vIL-8). Phylogenetic analysis was conducted using MEGA 12 software to determine the genetic relationships between Tanzanian isolates and MDV strains from Africa and other continents. The results confirm the widespread circulation of MDV in Tanzania, with an overall prevalence of 18.08% across all surveyed zones. Molecular characterization of the meq, pp38, and vIL-8 genes revealed high sequence similarity with previously reported MDV strains from Egypt, Nigeria, Israel, and China, with clustering observed in the phylogenetic analysis. Notably, Tanzanian MDV strains exhibited amino acid substitutions associated with increased virulence, particularly in the meq gene, which plays a crucial role in MDV-induced tumorigenesis. These findings suggest that MDV strains in Tanzania have undergone genetic changes that could potentially affect vaccine efficacy. Therefore, this study provides valuable information for vaccine manufacturers, poultry farmers, and policymakers in Tanzania, enabling informed decisions when selecting vaccines for MD control. Full article

Yakutia, the largest breeding ground for wild migratory birds in Northeastern Siberia, plays a big role in the global ecology of avian influenza viruses (AIVs). In this study, we present the results of virological surveillance conducted between 2018 and 2023, analyzing 1970 cloacal swab samples collected from 56 bird species. We identified 74 AIVs of H3N6, H3N8, H4N6, H5N3, H7N7, H10N3, and H11N9 subtypes in Anseriformes order. Phylogenetic analysis showed that the isolates belong to the Eurasian lineage and have genetic similarities with strains from East Asia, Europe, and North America. Cluster analysis has demonstrated the circulation of stable AIV genotypes for several years. We assume that Yakutia is an important territory for viral exchange on the migratory routes of migrating birds. In addition, several amino acid substitutions have been found to be associated with increased virulence and adaptation to mammalian hosts, highlighting the potential risk of interspecific transmission. These results provide a critical insight into the ecology of the AIV and highlight the importance of continued monitoring in this geographically significant region. Full article

Despite extensive experience with influenza surveillance in humans in Senegal, there is limited knowledge about the actual situation and genetic diversity of avian influenza viruses (AIVs) circulating in the country, hindering control measures and pandemic risk assessment. Therefore, as part of the “One Health” approach to influenza surveillance, we conducted active AIV surveillance in two live bird markets (LBMs) in Dakar to better understand the dynamics and diversity of influenza viruses in Senegal, obtain genetic profiles of circulating AIVs, and assess the risk of emergence of novel strains and their transmission to humans. Cloacal swabs from poultry and environmental samples collected weekly from the two LBMs were screened by RT-qPCR for H5, H7, and H9 AIVs. Subsequently, a subset of H9-positive samples was selected for whole sequencing. From December 2023 to October 2024, 499 samples were tested, and AIV was detected in 58.3% of them. Among these, A/H9N2 was the only subtype detected in both markets, with a detection rate of 47.7% (82/172) in Thiaroye and 35.3% (42/119) in Tilene, resulting in an overall positivity rate of 42.6% (124/291). Genome sequencing of 22 A/H9N2 isolates, including 11 poultry drinking water samples, 7 carcass wash water samples, 3 fecal samples, and 1 cloacal swab, yielded 7 complete and 15 partial genomic sequences. Phylogenetic analyses of the resulting sequences showed that the A/H9N2 isolates obtained in this study formed a monophyletic cluster and were closely related to the Senegalese human strain (A/Senegal/0243/2019) identified through the national influenza sentinel surveillance program. These strains were also closely related to the A/H9N2 viruses of the G1 lineage circulating in neighboring countries, suggesting cross-border transmission. The A/H9N2 strains carried the low pathogenicity RSSR/GLF motif at the HA cleavage site and possessed several key amino acid mutations, including HA-I155T and HA-Q226L, which are associated with human host adaptation, PB2-T105V, PB2-A661T, and PB2-A588V, which are linked to the human-to-human transmission and increased polymerase activity, NS2-T14M, NS2-M100I, NS1-I106M, NS1-V222M, NS1-E223A, NS1-I226V, NS1-E227G, and NS1-P228S, which are known to alter virulence (increased or reduced) in humans or mice, and M2-S31N, which promotes drug resistance. Seven potential N-glycosylation sites were predicted in the HA protein and six in the NA protein. The selection pressure analysis revealed that the A/H9N2 isolates were primarily under neutral evolution or purifying selection pressure. Overall, our findings highlight the potential for cross-species transmission of Senegalese A/H9N2 viruses, emphasizing the need for sustained monitoring of these viruses in both animal and human populations. Full article

Background: Probiotics, which are live microorganisms that, when given in sufficient quantities, promote the host’s health, have drawn a lot of interest for their ability to enhance gut health. Enterococcus faecalis, a member of the human gut microbiota, has shown promise as a probiotic candidate due to its functional attributes. However, safety concerns associated with certain strains warrant comprehensive evaluation before therapeutic application. Materials and Methods: In this study, E. faecalis EF-2001, originally isolated from fecal samples of a healthy human infant, was subjected to a multi-faceted assessment for its safety and probiotic potential. In silico analysis, CAZyme, biosynthetic, and stress-responsive proteins were identified. Results: The genome lacked biogenic amine genes but contained some essential amino acid and vitamin synthetic genes, and carbohydrate-related enzymes essential for probiotic properties. The negligible difference of 0.03% between the 1^st and 25^th generations indicates that the genetic information of the E. faecalis EF-2001 genome remained stable. The live E. faecalis EF-2001 (E. faecalis EF-2001L) demonstrated low or no virulence potential, minimal D-Lactate production, and susceptibility to most antibiotics except some aminoglycosides. No bile salt deconjugation or biogenic amine production was observed in an in vitro assay. Hemolytic activity assessment showed a γ-hemolytic pattern, indicating no red blood cell lysis. Furthermore, the EF-2001L did not produce gelatinase and tolerated simulated gastric and intestinal fluids in an in vitro study. Similarly, heat-killed E. faecalis EF-2001 (E. faecalis EF-2001HK) exhibits tolerance in both acid and base conditions in vitro. Further, no cytotoxicity of postbiotic EF-2001HK was observed in human colorectal adenocarcinoma HT-29 cells. Conclusions: These potential properties suggest that probiotic and postbiotic E. faecalis EF-2001 could be considered safe and retain metabolic activity suitable for human consumption. Full article

Staphylococcus aureus and coagulase-negative staphylococci account for about 80% of infections associated with medical devices and are associated with increased virulence due to their ability to form biofilm. In this study, we aimed to construct a comprehensive reference map followed by significant pathway analysis in the proteome of S. aureus biofilm grown for 3 days compared with 24 h of planktonic culture using a high-resolution Tandem Mass Tag (TMT)-based MS. We identified proteins associated with secondary metabolites, ABC transporters, biosynthesis of amino acids, and response to stress, and amino sugar and nucleotide sugar metabolism were significantly upregulated in 3-day biofilm. In contrast, proteins associated with virulence factors, microbial metabolism in diverse environments, secondary metabolites, translation, and energy metabolism were significantly downregulated. GO functional annotation indicated that more proteins are involved in metabolic processes, catalytic activity, and binding in biofilm, respectively. Among the significantly dysregulated proteins, hyaluronidase (hysA) in conjunction with chitinase may play a significant role in the elimination and/or prevention of biofilm development. This study advances the understanding of the S. aureus subproteome, identifying potential pathways significant to biofilm biology. The insights gained may aid in developing new therapeutic strategies, including antibiofilm agents, for treating biofilm-related infections associated with implantable medical devices. Full article

Listeria monocytogenes (L. monocytogenes) is a pathogen that is transmitted through contaminated food and causes the illness known as listeriosis. The virulence factor InlA plays a crucial role in the invasion of L. monocytogenes into the human intestinal epithelium. In addition, InlA enhances the pathogenicity of host strains, and different strains of L. monocytogenes contain varying variations of InlA. Our study analyzed a total of 4393 published L. monocytogenes genomes from 511 sequence types (STs) of diverse origins. We identified 300 unique InlA protein sequence types (PSTs) and revealed 45 highly mutated amino acid sites. The leucine-rich repeat (LRR) region was found to be the most conserved among the InlA, while the protein A (PA) region experienced the highest mutation rate. Two new types of mutations were identified in the B-repeat region of InlA. Correspondence analysis (CA) was used to analyze correlations between the lineages or 10 most common sequence types (STs) and amino acid (aa) sites. ST8 was strongly correlated with site 192_F, 454_T. ST7 exhibited a strong correlation with site 51_A, 573_E, 648_S, and 664_A, and it was also associated with ST6 and site 544_N, 671_A, 738_B, 739_B, 740_B, and 774_Y. Additionally, a strong correlation between ST1 and site 142_S, 738_N, ST2 and site 2_K, 142_S, 738_N, as well as ST87 and site2_K, 738_N was demonstrated. Our findings contribute significantly to the understanding of the distribution, composition, and conservation of InlA in L. monocytogenes. These findings also suggest a potential role of InlA in supporting molecular epidemiological tracing efforts. Full article

As an epizootic causative agent, the Getah virus (GETV) can cause moderate illness in horses, lethal disease in foxes, and reproductive disorders and fetal death in pigs. Due to the wide range of hosts and multiple routes of transmission, GETV has become a growing potential threat to the global livestock industry, and even to public health. More attention and research on GETV are urgently needed. In this study, we successfully isolated a novel GETV strain, named BJ0304, from a commercial live vaccine against porcine reproductive and respiratory syndrome virus (PRRSV) and determined its growth kinetics. Then, genetic and phylogenetic analyses were performed. The results revealed that BJ0304 was clustered into Group III, and it was most related to the GETV-V1 strain based on the complete genome sequence. Furthermore, the pathogenicity of the isolate was assessed and found to be a low virulent strain in mice relative to its closest homolog GETV-V1. Finally, mutation and glycosylation analysis showed that a unique mutation (171 T > I) at one amino acid of E2, which affected the glycosylation of E2, may be associated with viral pathogenicity. In summary, the general characteristic of a novel Group III-classified GETV-BJ0304 isolated from commercial live PRRSV vaccine was defined and then mutation/glycosylation-related potential virulence factor was discussed. This study highlights the complexity of GETV transmission routes in swine and the need for more surveillance on commercial animal vaccines, contributes to the understanding of genetic characterization of clinical isolates, provides possible virulence factors in favor of unveiling the viral pathogenesis, and eventually lays the foundation for the prevention and control of GETV. Full article