Infectious Agents Research Articles

Anti-viral Effects of Pavetta indica Methanolic Extract and Acyclovir on Behavioral and Biochemical Parameters in Streptozotocin-induced Alzheimer's Disease in Rats.

Alzheimer's disease is a neurological dysfunction of the brain caused by neurodegeneration and oxidative stress. Some viruses, such as herpes viruses, HSV-1, and HSV-2, are causative agents of Alzheimer's disease and result in β-amyloid peptide and tau protein accumulation in the brain. Some antiviral drugs, such as valacyclovir, acyclovir, and foscarnet, reduce amyloid-beta and P-tau. Pavetta indica leaves are also reported for their antiviral properties. The current study aimed to find out the significance of using Pavetta indica methanolic extract and acyclovir against Alzheimer's disease induced by streptozotocin. Wistar rats received acyclovir and Pavetta indica methanolic extract orally at different dose ranges (50, 150, 450 mg/kg) and (125, 250, 500 mg/kg), respectively. The standard therapy, Rivastigmine (2 mg/kg), was given orally. Intracerebroventricular-streptozotocin produced significant alternations in behavioral assessments, including locomotor activity test, Morris water maze test, and elevated plus maze test. Moreover, intracerebroventricular-streptozotocin ameliorated the antioxidant defense activity by decreasing levels of catalase, superoxide dismutase, and reduced glutathione while enhancing the oxidative stress markers, including malondialdehyde, and total nitrite levels. Finally, the main findings showed that intracerebroventricular-streptozotocin significantly increased the inflammatory marker, tumor necrosis factor-α, and disturbed neurotransmitter mediators, including levels of acetylcholinesterase, glutamate, and γ-amino butyric acid. In a dose-dependent manner, acyclovir and Pavetta indica methanolic extract treatments abrogated the streptozotocin-induced behavioral and neurological abnormalities in rats. The potential therapeutic effects of PIME and acyclovir administration in intracerebroventricular-streptozotocin-treated rats may be attributed to its potential antiviral, antioxidant, and anti-inflammatory effects. The current study suggests that Pavetta indica methanolic extract and acyclovir are promising therapeutic targets against Alzheimer's disease.

Chromatin accessibility profile and the role of PeAtf1 transcription factor in the postharvest pathogen Penicillium expansum

Abstract Gene transcription is governed by a complex regulatory system involving changes in chromatin structure, action of transcription factors, and activation of cis-regulatory elements. Postharvest fruits are threatened by Penicillium expansum, a leading causal agent of blue mold disease and one of the most economically significant postharvest pathogens worldwide. However, the information on its transcription regulatory mechanism is lagging. Here, we conducted an assay for transposase accessible chromatin sequencing (ATAC-seq) for P. expansum during vegetative growth and infection phase and then studied the function of a bZIP transcription factor PeAtf1. Results highlighted the role of promoter regions in gene transcription and the significant difference in P. expansum between the two phases. Six footprint-supported cis-regulatory elements of active transcription factors were obtained and analyzed. We then identified a homolog of the bZIP regulator Atf1, PeAtf1, and found it positively regulated vegetative growth, reproduction and osmotic stress response in P. expansum. Conversely, PeAtf1 deletion enhanced fungal tolerance to oxidative, cell wall and membrane stresses, which might contribute to the virulence of P. expansum in apple fruits, leading to similar pathogenicity between mutants and the wild type. Overall, this study provides new insights into the transcription regulatory mechanism of P. expansum, aiding in the future development of strategies to control P. expansum.

Unveiling the Hidden Enemies: Morphological and Molecular Characterization of Pod Rot Pathogens in Groundnut (Arachis hypogea L.) in India

Pod rot of groundnut is a complex disease caused by multiple pathogens causes significant economic losses. Present study was undertaken to know the pathogens associated with the disease. In Chittoor, Andhra Pradesh, roving survey against pod rot of groundnut revealed association of three fungal species: Sclerotium rolfsii, Rhizoctonia bataticola and Fusarium spp. Molecular analysis with modified CTAB method and performing PCR using ITS1 and ITS4 primers yielded DNA bands of 650-700 bp, 550-600 bp, and 500-600 bp for Sclerotium, Rhizoctonia and Fusarium species, respectively. Sequencing of the rDNA ITS region confirmed the identities of the pathogens as Sclerotium rolfsii, Rhizoctonia bataticola, Fusarium solani, Fusarium oxysporum, and Fusarium keratoplasticum, based on similarity with NCBI reference sequences. This study confirms that Sclerotium rolfsii, Rhizoctonia bataticola and Fusarium spp. are the primary causal agents of pod rot disease in Andhra Pradesh.

HRS Facilitates Newcastle Disease Virus Replication in Tumor Cells by Promoting Viral Budding

Newcastle disease virus (NDV) is a highly pathogenic avian infectious disease agent and also a promising oncolytic virus with broad application prospects. The Endosomal Sorting Complex Required for Transport (ESCRT) machinery has been increasingly recognized for its crucial role in the life cycles of enveloped viruses, influencing processes such as viral entry, replication, and budding. In this study, we employed an RNA interference screening approach to identify key ESCRT components that regulate NDV replication in tumor cells. qPCR, immunofluorescence, and Western blot assays demonstrated that knockdown of HRS, CHMP4A, CHMP4B, and CHMP4C significantly impaired NDV replication in HeLa cells, with HRS exhibiting the most pronounced inhibitory effect. Additionally, HRS knockout significantly inhibited viral budding and suppressed NDV-induced cell death in HeLa cells. Notably, NDV infection was shown to significantly upregulate HRS gene and protein expression in a time-dependent manner. In conclusion, this study systematically identifies critical ESCRT components involved in NDV replication within tumor cells, with a particular focus on the role of HRS in promoting NDV’s replication by promoting viral budding, offering new insights for the development of NDV-based oncolytic therapies.

Genome-wide survey of the bipartite structure and pathogenesis-related genes of Neostagonosporella sichuanensis, a causal agent of Fishscale bamboo rhombic-spot disease

Bamboo resources have garnered significant global attention due to their excellent capacity for regeneration and high yield. Rhombic-spot disease, a substantial threat to fishscale bamboo (Phyllostachys heteroclada), is primarily caused by Neostagonosporella sichuanensis. This study first reported the genome assemblies and characteristics of two N. sichuanensis isolates using PacBio and Illumina sequencing platforms. The genomes of N. sichuanensis strain SICAUCC 16–0001 and strain SICAUCC 23–0140, with sizes of 48.0 Mb and 48.4 Mb, respectively, revealed 10,289 and 10,313 protein-coding genes. Additionally, they contained 34.99 and 34.46% repetitive sequences within AT-rich regions, with notable repeat-induced point mutation activity. Comparative genome analysis identified 1,049 contracted and 45 expanded gene families in the genome of N. sichuanensis, including several related to pathogenicity. Several gene families involved in mycotoxin metabolism, secondary metabolism, sterol biosynthesis and transport, and cell wall degradation were contracted. Compared to most analyzed necrotrophic, hemibiotrophic, and phaeosphaeriacous pathogens, the genomes of two N. sichuanensis isolates exhibited fewer secondary metabolite enzymes, carbohydrate-active enzymes, plant cell wall degrading enzymes, secreted proteins, and effectors. Comparative genomics analysis suggested that N. sichuanensis shares more similar characteristics with hemibiotrophic pathogens. Based on single carbon source tests, N. sichuanensis strains demonstrated a higher potential for xylan decomposition than pectin and cellulose. The proportion of cell wall-degrading enzyme effectors occupied a high proportion of the total effectors of the N. sichuanensis genomes. These findings provide valuable insights into uncovering the pathogenesis of N. sichuanensis toward the efficient management of rhombic-spot disease of fishscale bamboo.

Probiotics as a potential tool for gynecological cancers prevention and therapy suport

The human body is host to a variety of microbial species that are essential for maintaining general health. About nine percent of these microbial species inhabit the urogenital tract. It is therefore important to establish a symbiotic relationship between the host’s immune system and the microbiota in this region. Disruptions of this symbiosis can contribute to the development of pelvic inflammatory disease (PID), bacterial vaginosis (BV), vaginal candidiasis and/or even gynaecological cancers by promoting the proliferation of infectious agents. The chemotherapeutic agents currently used in cancer treatment are associated with undesirable side effects. Therefore, there is an urgent need for antitumor agents that have minimal toxicity compared to conventional treatments. Furthermore, the use of drugs to prevent or alleviate the side effects of cervical cancer treatment could significantly improve the quality of life of patients undergoing such therapy. In this review, we focus our attention on the potential efficacy of probiotics in both the prevention and therapeutic intervention of neoplasms affecting the genital tract.

Genomic investigation of innate sensing pathways in the tumor microenvironment

The innate immune system is the first responder to infectious agents, cellular debris, and cancerous growths. This system plays critical roles in the antitumor immune responses by boosting and priming T cell-mediated cytotoxicity but is understudied due to the complexity and redundancy of its various downstream signaling cascades. We utilized a mathematical tool to holistically quantify innate immune signaling cascades and immunophenotype over 8,000 tumors from The Cancer Genome Atlas (TCGA). We found that innate immune activation was predictive of patient mortality in a subset of cancers. Further analysis identified PHF genes as transcripts that were associated with genomic stability and innate activation. Knockdown of PHF gene transcripts in vitro led to an increase in cell death and IFNB1 expression in a cGAS-dependent manner, validating PHF genes as potential anti-tumor targets. We also found an association between innate immune activation and both tumor immunogenicity and intratumor microbes, which highlights the versatility of this model. In conclusion, interrogating activation of innate immune signaling cascades demonstrated the importance of studying innate signaling in cancer and broadened the search for new therapeutic adjuvants.

Impact of COVID-19 on myalgic encephalomyelitis/chronic fatigue syndrome-like illness prevalence: A cross-sectional survey.

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) can be triggered by infectious agents including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, the impact of the coronavirus disease 2019 (COVID-19) pandemic on ME/CFS prevalence is not well characterized. In this population-based cross-sectional study, we enrolled a stratified random sample of 9,825 adult participants in the Kaiser Permanente Northern California (KPNC) integrated health system from July to October 2022 to assess overall ME/CFS-like illness prevalence and the proportion that were identified following COVID-19 illness. We used medical record and survey data to estimate the prevalence of ME/CFS-like illness based on self-reported symptoms congruent with the 2015 Institute of Medicine ME/CFS criteria. History of COVID-19 was based on a positive SARS-CoV-2 nucleic acid amplification test or ICD-10 diagnosis code in the medical record, or self-report of prior COVID-19 on a survey. Of 2,745,374 adults in the eligible population, an estimated 45,892 (95% confidence interval [CI]: 32,869, 58,914) or 1.67% (CI 1.20%, 2.15%) had ME/CFS-like illness. Among those with ME/CFS-like illness, an estimated 14.12% (CI 3.64%, 24.6%) developed the illness after COVID-19. Among persons who had COVID-19, those with ME/CFS-like illness after COVID-19 were more likely to be unvaccinated and to have had COVID-19 before June 1, 2021. All persons with ME/CFS-like illness had significant impairment in physical, mental, emotional, social, and occupational functioning compared to persons without ME/CFS-like illness. In a large, integrated health system, 1.67% of adults had ME/CFS-like illness and 14.12% of all persons with ME/CFS-like illness developed it after COVID-19. Though COVID-19 did not substantially increase ME/CFS-like illness in the KPNC population during the study time period, ME/CFS-like illness nevertheless affects a notable portion of this population and is consistent with estimates of ME/CFS prevalence in other populations. Additional attention is needed to improve awareness, diagnosis, and treatment of ME/CFS.

Rare cases of primarily infected kidney graft transplantation with the development of purulent complications

Background. Unexpected transmission of an infectious disease agent with a kidney graft to a recipient is a rare event but it is associated with significant morbidity and mortality, especially when exposed to multidrug-resistant bacteria that have not been eliminated by standard antibiotic prophylaxis.Objective. To demonstrate the need for immediate removal of a primary infected kidney graft in the event of local purulent complications due to the rapid development of sepsis in immunocompromised patients.Results. The paper describes a clinical course of the infectious process in two kidney recipients each of whom underwent transplantation of a primary infected graft from a single donor, taking into consideration the transplantectomy timing and the treatment outcomes.Conclusion. The Case Report shows the need for immediate transplantectomy in a kidney graft recipient when local purulent complications are detected with confirmed primary infection of the graft due to a high risk of the rapid development of sepsis and threat to life.

Terbinafine Resistance in Trichophyton Strains Isolated from Humans and Animals: A Retrospective Cohort Study in Italy, 2016 to May 2024

Background: In recent decades, globalization and international migration have increased the spread of infectious agents, including dermatophytes. Although considered minor infections, dermatophytoses are highly contagious, and they significantly reduce the quality of life, inducing itching, burning, sleep disturbances, and even depressive states. Moreover, the increasing resistance to antifungals threats the public health and burdens the costs for the healthcare system. Methods: DermaGenius® Resistance Multiplex real-time PCR assay allowed to analyze the terbinafine susceptibility/resistance of 172 Trichophyton strains, which were isolated from human and animal samples collected from 2016 to May 2024 and previously identified by Sanger sequencing. Results: All the 11 animal strains belonged to the T. interdigitale/T. mentagrophytes complex and tested terbinafine sensitive. Out of 161 human strains, 9 (5.6%) showed terbinafine resistance and 7 (4.3%) were identified as T. indotineae. Conclusions: This study provides preliminary data about behavior toward antifungals in animals and finalizes the scientific information currently available about human strains, highlighting the importance of the One Health concept. Moreover, it supports the relevant role of T. indotineae as an emerging dermatophyte with high proportion of terbinafine resistance.

A reporter Oropouche virus expressing ZsGreen from the M segment enables pathogenesis studies in mice.

Oropouche fever caused by Oropouche virus (OROV) is a significant zoonosis in Central and South America. Despite its public health significance, we lack high-throughput diagnostics, therapeutics, and a comprehensive knowledge of OROV biology. Reporter viruses are valuable tools to rapidly study virus dynamics and develop neutralization and antiviral screening assays. OROV is a tri-segmented bunyavirus, which makes generating a reporter virus challenging, as introducing foreign elements into the viral genome typically affects fitness. We previously demonstrated that the non-structural gene NSm on the OROV medium (M) segment is non-essential for replication in vitro. Taking advantage of this, we have now generated a recombinant OROV expressing fluorescent protein ZsGreen in place of NSm. This reporter OROV is both stable and pathogenic in IFNAR-/- mice and provides a powerful tool for OROV pathogenesis studies and assay development.IMPORTANCEEmerging and reemerging infectious agents such as zoonotic bunyaviruses are of global health concern. Oropouche virus (OROV) causes recurring outbreaks of acute febrile illness in the Central and South American human populations. Biting midges are the primary transmission vectors, whereas sloths and non-human primates are their reservoir hosts. As global temperatures increase, we will likely see an expansion in arthropod-borne pathogens such as OROV. Therefore, developing reagents to study pathogen biology to aid in identifying druggable targets is essential. Here, we demonstrate the feasibility and use of a fluorescent OROV reporter in mice to study viral dynamics and pathogenesis. We show that this reporter OROV maintains characteristics such as growth and pathogenicity similar to the wild-type virus. Using this reporter virus, we can now develop methods to assist OROV studies and establish various high-throughput assays.

Development of novel multi-protein chimeric immunogens that protect against infection with the Lyme disease agent, Borreliella burgdorferi.

Lyme disease is the most common tick-borne disease in North America. A vaccine for use in humans is not available. Here, we detail the development of two chimeric vaccine antigens, BAF and Chv2M. BAF elicits Abs that target proteins and protein variants produced by Borreliella species in ticks (OspB and OspA) and mammals (FtlA/B). OspB serves as the backbone structure for the BAF chimeric. Two OspA221-240 epitope-containing domain (ECD) variants (#A1 and #A15) were inserted into a loop in OspB. The N-terminal region of the FtlA protein was joined to the C-terminus of the chimeric. The second chimeric, Chv2M, consists of L5 (loop 5) and H5 (helix 5) ECDs derived from diverse OspC proteins. Borreliella species produce OspC upon exposure to the bloodmeal and during early infection in mammals. Here, we demonstrate that BAF and Chv2M are potent immunogens that elicit Abs that bind to each component protein (FtlA, FtlB, OspB, and multiple OspA and OspC variants). Anti-BAF and anti-Chv2M Abs kill Borreliella burgdorferi strains through Ab-mediated complement-dependent and complement-independent mechanisms. Eighty percent (32/40) of mice that received a three-dose vaccine regimen were protected from infection with B. burgdorferi B31. Efficacy increased to 90% (18/20) when the amount of Chv2M was increased in the third vaccine dose. Readouts for infection were flaB PCR and seroconversion to VlsE. This study establishes proof of principle for a chimeric immunogen vaccine formulation that elicits Abs to multiple targets on the B. burgdorferi cell surface produced during tick and mammalian stages of the enzootic cycle.IMPORTANCELyme disease is a growing public health threat across parts of the Northern Hemisphere. Regions that can support sustained tick populations are expanding, and the incidence of tick-borne diseases is increasing. In light of the increasing risk of Lyme disease, effective preventive strategies are needed. Most vaccine development efforts have focused on outer surface protein A, a Borreliella burgdorferi protein produced only in ticks. Herein, we describe the development of a novel vaccine formulation consisting of two multivalent chimeric proteins that are immunogenic and elicit antibodies with bactericidal activity that target several cell surface proteins produced by the Lyme disease spirochetes in feeding ticks and mammals. In a broader sense, this study advances efforts to develop custom-designed vaccinogens comprised of epitope-containing domains from multiple proteins.

Fighting Pancreatic Cancer with a Vaccine-Based Winning Combination: Hope or Reality?

Pancreatic adenocarcinoma (PDA) represents the fourth leading cause of cancer-related mortality in the USA. Only 20% of patients present surgically resectable and potentially curable tumors at diagnosis, while 80% are destined for poor survival and palliative chemotherapy. Accordingly, the advancement of innovative and effective therapeutic strategies represents a pivotal medical imperative. It has been demonstrated that targeting the immune system represents an effective approach against several solid tumors. The immunotherapy approach encompasses a range of strategies, including the administration of antibodies targeting checkpoint molecules (immune checkpoint inhibitors, ICIs) to disrupt tumor suppression mechanisms and active immunization approaches that aim to stimulate the host’s immune system. While vaccines have proved effective against infectious agents, vaccines for cancer remain an unfulfilled promise. Vaccine-based therapy targeting tumor antigens has the potential to be a highly effective strategy for initiating and maintaining T cell recognition, enhancing the immune response, and ultimately promoting cancer treatment success. In this review, we examined the most recent clinical trials that employed diverse vaccine types to stimulate PDA patients’ immune systems, either independently or in combination with chemotherapy, radiotherapy, ICIs, and monoclonal antibodies with the aim of ameliorating PDA patients’ quality of life and extend their survival.

Clinical evolution of patients with infection associated with orthopedic devices in treatment with continuous negative pressure

To describe the use of negative pressure therapy with (TPNi) and without instillation (TPNs) as adjuvant treatment in the management of orthopedic device-associated infections (IADO). Analytic observational study of records of patients with IADO managed with TPNi and TPNs with 0.9% saline solution, in patients > 18 years, operated on in 2018-2021. Clinical characteristics of infection, infectious agent as well as sociodemographic variables were evaluated. TPN was performed with the V.A.C. VERAFLO™ system. Analysis with χ2, Fisher and t-Student. Statistically accepted value p < 0.05. Sample 40 patients. 75% male. Fractures 42.5% exposed and 57.5% closed. 92.5% applied prophylactic antibiotic (30-120 min). 35% plate implants, 12.5% centromedullary nail, 10% knee prosthesis and 12.5% hip. 47.5% bleeding < 500 ml. 72.5% surgical time of 2-4 hours. Previous hospitalization time, TPNs 3 weeks 55.9% and 4 weeks 26.5%; TPNi, 3 weeks 50% and 4 weeks 33.3%. Conservation of the implant 73.5% TPNs and 50% TPNi (p = 0.341). Wound closure 91.2% with TPNs and 100% with TPNi (p = 1.000). The use of TPNs and TPNi were useful as adjuvant treatments in the management of IADO, in addition they allowed to preserve the implant and wound closure in a large part of the patients.

Is SARS-CoV-2 the only cause of long-COVID?

Around 10% of adults infected with SARS-CoV-2 that survive a first episode of COVID-19 appear to experience long-term clinical manifestations. The signs and symptoms of this post-acute COVID-19 syndrome (PACS) include fatigue, dyspnea, joint pain, myalgia, chest pain, cough, anosmia, dysgeusia, headache, depression, anxiety, memory loss, concentration difficulties, and insomnia. These sequelae remind the constellation of clinical manifestations previously recognized as myalgic encephalomyelitis (ME) or chronic fatigue syndrome (CFS). This condition has been described following distinct infectious events, mostly acute viral illnesses. In this way, the pathophysiology of PACS might overlap with mechanisms involved in other post-infectious fatigue syndromes. The risk of PACS is more frequent in women than men. Additional host genetic factors could be involved. There is a dysregulation of multiple body organs and systems, involving the immune system, the coagulation cascade, endocrine organs, autonomic nervous system, microbiota-gut-brain axis, hypothalamic-pituitary-adrenal axis, hypothalamic-pituitary-thyroid axis, etc. Hypothetically, an abnormal response to certain infectious agents could trigger the development of postinfectious fatigue syndromes.

In silico analysis of secreted effectorome of the rubber tree pathogen Rigidoporus microporus highlights its potential virulence proteins

Rigidoporus microporus, the causative agent of the white root rot disease of rubber trees, poses a significant threat to natural rubber production worldwide. Understanding the molecular mechanisms facilitating its pathogenicity would be crucial for developing effective disease management strategies. The pathogen secretes effector proteins, which play pivotal roles in modulating host immune responses and infection. In this study, in silico analyses identified 357 putative secreted effector proteins from the R. microporus genome. These were then integrated into previous RNA-seq data obtained in response to rubber tree latex exposure. Annotation of putative effectors suggested the abundance of proteins in several families associated with the virulence of R. microporus, especially hydrophobin proteins and glycoside hydrolase (GH) proteins. The contribution of secreted effectors to fungal pathogenicity was discussed, particularly in response to rubber tree latex exposure. Some unknown highly expressed effectors were predicted for the protein structures, revealing their similarity to aminopeptidase, ubiquitin ligase, spherulin, and thaumatin protein. This integrative study further elucidates the molecular mechanism of R. microporus pathogenesis and offers alternative targets for developing control strategies for managing white root rot disease in rubber plantations.

Unveiling the Full Protein Effectorome of the Black Sigatoka Pathogen Pseudocercospora fijiensis—An In Silico Approach

Pseudocercospora (previously Mycosphaerella) fijiensis is a hemibiotroph fungus and the causal agent of black Sigatoka disease, one of the most significant threats to banana production worldwide. Only a few genomics reports have paid any attention to effector proteins, which are key players in pathogenicity. These reports focus on canonical effectors: small secreted proteins, rich in cysteines, containing a signal peptide and no transmembrane domain. Thus, bias in previous reports has resulted in the non-canonical effectors being, in effect, excluded from the discussion of effectors in P. fijiensis pathogenicity. Here, using WideEffHunter and EffHunter, bioinformatic tools which identify non-canonical and canonical effectors, respectively, we predict, for the first time, the full effectorome of P. fijiensis. This complete effectorome comprises 5179 proteins: 240 canonical and 4939 non-canonical effectors. Protein families related to key functions of the hemibiotrophic lifestyle, such as Salicylate hydroxylase and Isochorismatase, are widely represented families of effectors in the P. fijiensis genome. An analysis of the gene distribution in core and dispensable scaffolds of both classes of effectors revealed a novel genomic structure of the effectorome. The majority of the effectors (canonical and non-canonical) were found to be harbored in the core scaffolds, while dispensable scaffolds harbored less than 10% of the effectors, all of which were non-canonical. Additionally, we found the motifs RXLR, YFWxC, LysM, EAR, [Li]xAR, PDI, CRN, and ToxA in the effectors of P. fijiensis. This novel genomic structure of effectors (more enriched in the core than in the dispensable genome), as well as the occurrence of effector motifs which were also observed in four other fungi, evidences that these phenomena are not unique to P. fijiensis; rather, they are widely occurring characteristics of effectors in other fungi.

147 The ‘horse-side’ of host-microbe interactions and gastrointestinal homeostasis in the equine hindgut

Abstract Homeostasis is a complex physiological process that enables biological systems to maintain balanced internal environments in response to internal and external stimuli. In the equine gastrointestinal (GI) tract, homeostasis involves a network of factors that regulate gene expression, maintain the integrity of the mucosal barrier, and modulate immune responses to pathogenic microorganisms while supporting commensal bacteria that provide benefits to the host (Figure 1). These factors work together and respond to changes in diet, environment, external stress, and challenges by infectious agents or toxins. Proper gastrointestinal function is dependent on maintaining homeostasis in the system, and the dynamic interactions between the microbial population (the microbiota) and the equine host are central to this equilibrium. The regulation and interplay between the equine host and GI microbiota are evident in the distribution of distinct microbial communities within the various compartments of the equine hindgut. The contributions of each compartment to digestive physiology and the overlap with various stages of microbial fermentation in the equine hindgut are well-researched. What remains to be documented is gene expression in tissues of the equine GI and the underlying role this might play in the processes of digestion, physiology, and homeostasis in the GI. To better understand the roles that host gene expression plays in the interactions with the microbiota, it is critical that we investigate gene expression in the different tissues along the intestinal tract. Protein-coding genes are crucial in maintaining the health of the gastrointestinal tract. They direct the synthesis of various structural elements, molecular transporters, and digestive enzymes, which support digestion, nutrient absorption, and gut integrity. Non-coding genes also play an important role in regulating protein-coding gene expression, modulating immune responses, and maintaining gut barrier function. Moreover, there is evidence that non-coding transcripts regulate the composition of microbial communities in the GI tract. The presentation will focus on the current research and future directions for investigating protein-coding and non-coding gene expression to understand the mechanisms involved in the host-microbe interaction in the equine hindgut and their potential role in maintaining GI homeostasis.

Biocontrol of fungal pathogens and growth promotion in the Korean fir (Abies koreana E.H.Wilson) seedling using Bacillus velezensis CE 100

The restoration of the endangered Korean fir (Abies koreana E.H.Wilson) forests requires mass production of high-quality and well-developed seedlings for outplanting. However, phytopathogenic fungal infections lower the survival rate and growth vigor of A. koreana seedlings, frustrating the re-afforestation efforts. This study isolated and identified the phytopathogenic fungi causing seedling blight and wilt diseases in A. koreana seedlings and investigated the potential of Bacillus velezensis CE 100 in controlling the fungal pathogens and promoting seedling growth. Phomopsis mali and Fusarium oxysporum were confirmed as the causal agents of blight and wilt diseases, respectively, and both fungi reduced the survival rate of A. koreana seedlings. B. velezensis CE 100 produced cell wall-degrading enzymes: chitinase, protease, and β-1,3-glucanase, and the bacterial crude enzyme fraction inhibited the spore germination and mycelial growth of P. mali and F. oxysporum in a concentration-dependent manner, causing severe morphological deformations. Consequently, treatment with B. velezensis CE 100 improved the survival rate of seedlings infected with either P. mali or F. oxysporum compared to the control and PB media treatment. The bacterium also increased nutrient availability through ammonia–nitrogen production and phosphate solubilization and produced indole-3-acetic acid (IAA), and its inoculation remarkably improved seedling growth (root and shoot dry weight) compared to the control and PB media treatment group. This is the first study to report P. mali and F. oxysporum as the pathogens causing seedling blight and wilt diseases in A. koreana nursery seedling, and the possibility of using B. velezensis CE 100 to control the fungal pathogens and improve the seedling growth without chemical use.

Pathology of tissue loss in three key gorgonian species in the Mediterranean Sea

The Mediterranean is known for its marine biodiversity, especially gorgonian forests. Unfortunately, these are experiencing rapid declines due to climate change, manifested by repeated marine heat waves resulting in mass mortality events since the early 1990 s. To better understand why gorgonians are declining, more systematic approaches to investigate the exact causes are needed, and pathology may aid in this goal.We described gross and microscopic pathology of tissue loss in three key gorgonian species in the Mediterranean region, Paramuricea clavata, Eunicella cavolini, and Leptogorgia sarmentosa, that were all experiencing various degrees of acute to subacute tissue loss characterized by exposed axial skeleton sometimes partly colonized by epibionts and thinning of adjacent tissues. The most significant variety of lesions was seen in P. clavata followed by L. sarmentosa and E. cavolini. For all species, dissociation of gastrodermal cells was the dominant microscopic lesion followed by necrosis of the gastrodermis. Ciliates invading gastrodermis and associated with necrosis of polyps were seen only in E. cavolini. Epidermal tissue loss was seen only in L. sarmentosa, while P. clavata was distinguished by a prominent inflammatory response and unidentified dark round structures within the tentacle epidermis and gastrodermis with no host response. Further work to understand the cause of death in gorgonians is needed, particularly to elucidate the role of ciliates and environmental co-factors or infectious agents not visible on light microscopy, as well as applications of additional tools such as cytology.