Disease-causing Pathogens Research Articles

Additions to the genus Kirschsteiniothelia (Dothideomycetes); Three novel species and a new host record, based on morphology and phylogeny

During a survey of microfungi associated with forest plants, four specimens related to Kirschsteiniothelia were collected from decaying wood in Guizhou, Hainan and Yunnan Provinces, China. Kirschsteiniothelia species have sexual and asexual forms. They are commonly found as saprophytes on decaying wood and have been reported as disease-causing pathogens in humans as well. In this study, we introduce three novel Kirschsteiniothelia species (K. bulbosapicalis, K. dendryphioides and K. longirostrata) and describe a new host record for K. atra, based on morphology and multi-gene phylogenetic analyses of a concatenated ITS, LSU and SSU rDNA sequence data. These taxa produced a dendryphiopsis- or sporidesmium-like asexual morph and detailed descriptions and micromorphological illustrations are provided. Furthermore, we provide a checklist for the accepted Kirschsteiniothelia species, including detailed host information, habitat preferences, molecular data, existing morphological type, country of origin and corresponding references.

Increased risk of infective endocarditis following transurethral resection of the prostate (TUR-P)

Abstract Background Transient bacteremia is a well-known complication of transurethral resection of the prostate (TUR-P). Still, the associated risk of bacteremia and subsequent infective endocarditis (endocarditis) after TUR-P has been sparsely examined. Purpose To examine the risk of bacteremia and infective endocarditis following TUR-P. Methods We identified all patients who underwent TUR-P between 2010-2020 with ICD-10 codes from Danish nationwide registries. Patients were compared to an age-matched cohort of males from the general population (1:1 match-ratio). We defined a 6-month exposure window following TUR-P and examined the risk of bacteremia and endocarditis within the first 6 months and compared with the following 6-12 months after TUR-P. Microbiology findings were based on complete data on blood culture results. Incidences of bacteremia and endocarditis were calculated, and groups were compared with cumulative incidences. To account for predisposing endocarditis risk factors, multivariable time-dependent Cox regression analyses were performed on the associated risk of bacteremia and endocarditis. Results In total, 25.781 patients underwent TUR-P. Median age was 70.7 years (IQR: 64.9-76.3). Incidence of bacteremia was higher in the TUR-P group than the control group (727.47 [681.49-776.56] per 10,000 person years vs 84.75 [95% CI: 70.19-102.35)] per 10,000 person years). Incidence of endocarditis was also higher in the TUR-P group than the control group (34.64 [95% CI: 25.78-46.55] per 10,000 person years vs 3.14 [95% CI: 1.18-8.35] per 10,000 person years). In 72.7% of endocarditis-cases, Enterococcus Faecalis was the disease-causing pathogen in the TUR-P group. As compared with an age-matched control group, we found an increased associated risk of bacteremia in patients undergoing TUR-P within the first 6 months from the procedure (adj. HR: 7.72 [95% CI: 6.25-9.53]) and the increased risk persisted within the following 6-12 months (adj. HR 2.31 [95% CI: 1.83-2.91]). TUR-P was also associated with endocarditis within 6 months from the procedure (8.16 [95% CI 3.06-21.79]), but not significantly the following 6-12 months after (2.15 [95% CI: 0.91-5.07]) as compared with the age-matched control group. Conclusion Transurethral resection of the prostate (TUR-P) is associated with an almost 8 times increased risk of bacteremia and an 8 times increased risk of infective endocarditis. Our findings emphasize the necessity for development of better preventive strategies against infective endocarditis after TUR-P.Risk of endocarditis post-TUR-P

Phycoremediation of Domestic Waste Water and Biodiesel Extraction from Fresh-Water Microalgae

ABSTRACT: Microalgae have recently drawn attention as a potential source for the sustainable production of biotechnologically valuable resources and improving the environment in various ways. They are widely distributed and can thrive even under extreme circumstances like high temperatures or high salinity. However, producing microalgae takes a lot of nutrients, which may have an adverse impact on the environment and the economy. The use of wastewater, particularly those from agro-industrial facilities, domestic waste waters, and industrial discharges, which often contain high nutrient concentrations, can serve as an alternative to synthetic culture media. Because the composition of wastewater and usual culture media is relatively similar, wastewater can be utilized to both clean itself and culture microalgae at the same time. Utilizing microalgae as wastewater bioremediation agents can efficiently remove N and P from domestic wastewater, maintain dissolved oxygen concentration, and reduce the various disease-causing pathogens and fecal bacteria that are present in domestic wastewater. The potential of microalgae to be used as a feedstock is increased by their ability to change the composition of their biomass under stress and accumulate lipids or carbohydrates that might be used to produce biodiesel. Methyl or ethyl esters of fatty acids produced from triglycerides by transesterification process by using renewable feedstocks are known as biodiesel. The microalgal biomass is considered as the next generation of feedstock for biofuel production. The Dual function of microalgae in domestic wastewater treatment and biomass growth for biodiesel production is outlined and discussed in detail in this review paper.

Wastewater genomic surveillance to track infectious disease-causing pathogens in low-income countries: Advantages, limitations, and perspectives

The emergence of infectious diseases, particularly those caused by respiratory pathogens like COVID-19 and influenza viruses, poses a significant threat to public health, especially in the context of climate change. Vulnerable variants and major pathogenicities are appearing, leading to a wide range of illnesses and increased morbidity. Wastewater genomic surveillance represents a cost-effective and a crucial tool for tracking infectious diseases, particularly in regions where clinical testing resources might be limited or inadequate. However, there are numerous limitations that need to be addressed in order to enhance its effectiveness for monitoring a wide range of pathogens. The current study uses this approach for the first time in Morocco to monitor the epidemiology of SARS-CoV-2 and Influenza A, B and RSV virus infections during the third wave of COVID-19 caused by the Omicron variant. The virome was concentrated from wastewater collected from two sewersheds of two cities, Agadir and Inezgane, using the the polyethylene glycol (PEG)/NaCl method. All 26 samples from both cities exhibited positive results for SARS-CoV-2, indicating varying viral loads. In the case of the Influenza A virus, four samples tested positive in Inezgane. However, no detection of Influenza B or RSV was observed in any of the samples. The estimated SARS-CoV-2 viral RNA copy numbers observed were then used to estimate the number of infected individuals using the SEIR model. The estimated number of cases correlates positively with the number of reported cases. Next Generation Sequencing showed that samples contain the following two variants: BA.1 and BA.2 that have been detected in clinical samples. In the case of Influenza A, clinical samples revealed a mild presence of the influenza virus subtype A(H3N2).This study demonstrates the effectiveness and feasibility of wastewater genomic surveillance in monitoring pathogens such as SARS-CoV-2 in Morocco. This approach can become an even more powerful tool for monitoring and predicting the spread of infectious diseases by addressing several key considerations. These include enhancing data collection methods, making environmental corrections for factors affecting RNA stability in wastewater, and refining mathematical models to improve their accuracy in predicting the number of infected cases. Incorporating statistical and machine learning models can further enhance the precision of these predictions.

Novel α-N-heterocyclic thiosemicarbazone complexes: synthesis, characterization, and antimicrobial of properties investigation.

In this paper, eight novel α-N-heterocyclic thiosemicarbazone complexes were synthesized in search of new biologically active compounds, and characterized via organic elemental analysis, nuclear magnetic resonance spectroscopy, infrared spectra, thermogravimetric analysis, ultraviolet-visible spectroscopy, molar conductance and magnetic susceptibility measurements. The in vitro antimicrobial activity of these complexes was examined against ten disease-causing pathogens: Gram-positive bacteria (Micrococcus luteus ATCC9341, Staphylococcus epidermidis ATCC12228, Bacillus cereus RSKK863) and Gram-negative bacteria (Pseudomonas aeroginosa ATCC27853, Klebsiella pneumonia ATCC27853, Enterobacter aerogenes ATCC51342, Salmonella typhi H NCTC9018394, Shigella dysenteria NCTC2966, Proteus vulgaris RSKK96026) and yeast (Candida albicans Y-1200-NIH). The results revealed that the α-N-heterocyclic thiosemicarbazone compounds showed potent activity. It was observed that all thiosemicarbazone complexes were more susceptible to Gram-negative strains based on the presence of an electron-withdrawing substituent (-Br/-Cl/-F). It was determined that thiosemicarbazone Cu2+complexes showed stronger antifungal effects.

Development of biomaterial composite hydrogel as a passive sampler with potential application in wastewater-based surveillance

Nowadays, the need to track fast-spreading infectious diseases has raised due to the recent COVID-19 disease pandemic. As a response, Wastewater-based Surveillance (WBS) has emerged as an early detection and disease tracking method for large populations that enables a comprehensive overview of public health allowing for a faster response from public health sector to prevent large outbreaks. The process to achieve WBS requires a highly intensive sampling strategy with either expensive equipment or trained personnel to continuously sample. The sampling problem can be addressed by passive sampler development. Chitosan-based hydrogels are recognized for their capability to sample and remove various contaminants from wastewater, including metals, dyes, pharmaceuticals, among others. However, chitosan-based hydrogels unique characteristics, can be exploited to develop passive samplers of genetic material that can be a very valuable tool for WBS. This study aimed to develop a novel chitosan hydrogel formulation with enhanced characteristics suitable for use as a passive sampler of genetic material and its application to detect disease-causing pathogens present in wastewater. The study evaluates the effect of the concentration of different components on the formulation of a Chitosan composite hydrogel (Chitosan, Glutaraldehyde, Microcrystalline cellulose (MCC), and Polyethylene glycol (PEG)) on the hydrogel properties using a Box Hunter & Hunter experimental matrix. Hydrogels’ weight, thickness, swelling ratio, microscopic morphology (SEM), FTIR assay, and zeta potential were characterized. The resulting hydrogel formulations were shown to be highly porous, positively charged (Zeta potential up to 35.80 ± 1.44 mV at pH 3) and with high water swelling capacity (up to 703.89 ± 15.00 %). Based on the results, a formulation from experimental design was selected and then evaluated its capacity to adsorb genetic material from a control spiked water with Influenza A virus synthetic vector. The adsorption capacity of the selected formulation was 4157.04 ± 64.74 Gene Copies/mL of Influenza A virus synthetic vector. The developed hydrogel showed potential to be used as passive sampler for pathogen detection in wastewater. However, deeper research can be conducted to improve adsorption, desorption and extraction techniques of genetic material from chitosan-hydrogel matrices.

Examining imidacloprid behaviorally resistant house flies (Musca domestica L.) (Diptera: Muscidae) for neonicotinoid cross-resistance.

The house fly (Musca domestica L.) is a ubiquitous fly species commonly associated with confined animal and urban waste storage facilities. It is known for its pestiferous nature and ability to mechanically vector numerous disease-causing pathogens. Effective control of adult house fly populations has traditionally relied upon insecticidal food baits; however, due to the overuse of insecticides, resistance has proven to yield many insecticidal baits and chemical classes less effective. Imidacloprid, the most widely used neonicotinoid, has been formulated and commonly used in house fly baits for over 2 decades. However, widespread evidence of physiological and behavioral resistance to imidacloprid has been documented. While previous studies have investigated the mechanisms of behavioral resistance to imidacloprid in the house fly, it remains unclear whether behavioral resistance is specific to imidacloprid or if behavioral cross-resistance exists to other compounds within the neonicotinoid class of insecticides. The current study used no-choice and choice-feeding bioassays to examine a lab-selected imidacloprid behaviorally resistant house fly colony for cross-resistance to other insecticides in the neonicotinoid chemical class. All flies exhibited high mortality (97-100%) in no-choice assays, even when exposed to imidacloprid, indicating physiological susceptibility to all tested neonicotinoids. House flies exhibited high mortality (98-100%) in choice assays when exposed to all neonicotinoid insecticides tested besides imidacloprid. These results confirm that imidacloprid behavioral resistance is specific to the compound imidacloprid and that alternative neonicotinoids remain viable options for control. Our study showed no evidence of behavioral cross-resistance to other compounds in the neonicotinoid class.

Analysis of the microbial community diversity in various regions of the healthy oral cavity

BackgroundMicrobiomics offers new methods for conducting epidemiological surveys of oral microbiota in large populations. Compared to curette sampling, swab sampling is more convenient and less technically sensitive, making it more suitable for such surveys. To verify the feasibility of using swabs for buccal mucosa sampling in large-scale studies, we collected samples from the buccal mucosa and tooth surfaces of healthy individuals using both swabs and curettes. Microbiomics was employed to analyze and compare microbial abundance and diversity between these two methods.MethodsFour sites were assessed: the buccal mucosa on both sides and the buccal surfaces of the left and right mandibular first molars. Two sampling methods, swab and curette, were used to collect bacterial communities from healthy individuals. Specifically, buccal mucosa samples (n = 10) and tooth surface samples (n = 20) were analyzed using 16 S rDNA gene sequencing. Bacterial signals were detected through fluorescence in situ hybridization (FISH), targeting the bacterial 16 S rDNA gene. Metastats analysis and Wilcoxon test were used.ResultsA total of 383 OTUs were detected in the 30 samples, which belonged to 1 kingdom (bacteria), 11 phyla, 23 classes, 40 orders, 75 families, 143 genus, and 312 species. Among them, 223 OTUs were found on both the buccal mucosa and tooth surfaces. The statistics suggest that although there were no significant differences in colony composition, there were differences in the abundance and distribution of colonies on the dental and buccal mucosal surfaces. When detecting oral disease-causing pathogens such as Enterococcus faecalis and Porphyromonas gingivalis, the efficiency of detection is higher when using curette sampling. Compared to right tooth sampling with a curette, the swab sampling group had higher levels of Firmicutes, while Fusobacteria and Bacteroidetes were more prevalent in the curette tissues.ConclusionsIn oral health individuals, there is no difference in the bacterial composition of the oral buccal mucosa and the dental surface, differing only in abundance. Thus, the buccal mucosa can act as a substitute for the teeth in epidemiological investigations exploring the bacterial composition of the oral cavity.

Description of BCG and Tuberculosis Disease in a Cohort of 79 Patients with Chronic Granulomatous Disease.

Chronic granulomatous disease (CGD) is an inherited immunodeficiency caused by pathogenic variants of genes encoding the enzyme complex NADPH oxidase. In countries where tuberculosis (TB) is endemic and the Bacillus Calmette-Guérin (BCG) vaccine is routinely administered, mycobacteria are major disease-causing pathogens in CGD. However, information on the clinical evolution and treatment of mycobacterial diseases in patients with CGD is limited. The present study describes the adverse reactions to BCG and TB in Mexican patients with CGD. Patients with CGD who were evaluated at the Immunodeficiency Laboratory of the National Institute of Pediatrics between 2013 and 2024 were included. Medical records were reviewed to determine the clinical course and treatment of adverse reactions to BCG and TB disease. A total of 79 patients with CGD were included in this study. Adverse reactions to BCG were reported in 55 (72%) of 76 patients who received the vaccine. Tuberculosis was diagnosed in 19 (24%) patients. Relapse was documented in three (10%) of 31 patients with BGC-osis and six (32%) of 19 patients with TB, despite antituberculosis treatment. There was no difference in the frequency of BCG and TB disease between patients with pathogenic variants of the X-linked CYBB gene versus recessive variants. This report highlights the importance of considering TB in endemic areas and BCG complications in children with CGD to enable appropriate diagnostic and therapeutic approaches to improve prognosis and reduce the risk of relapse.

Synthesis and in vitro Biological Assessments of Novel Thiazole-Based Thiosemicarbazone Complexes

In the present work, novel heterocyclic thiazole-based thiosemicarbazone Ag(I) complexes (Hc1, Hc2, Hc3) were obtained using the template method. The structures of synthesized thiosemicarbazone compounds were determined by some spectroscopic techniques (element analysis, infrared spectra (IR), thermogravimetric analysis (TGA), organic elemental analysis, and magnetic susceptibility measurements). The biological activities of novel heterocyclic thiazole-based thiosemicarbazone Ag(I) complexes werev screenedv in vitro against selected disease-causing pathogens (Micrococcus luteus ATCC9341, Staphylococcus epidermidis ATCC12228, Bacillus cereus RSKK863, Pseudomonas aeroginosa ATCC27853, Klebsiella pneumonia ATCC27853, Enterobacter aerogenes ATCC51342, Salmonellav typhi H NCTC9018394, Shigella dysenteria NCTC2966, Proteus vulgaris RSKK96026, Candidav albicans Y-1200-NIH) were as potential antimicrobial agents. It was determined that the thiazole-based thiosemicarbazone Ag(I) complexes exhibited high or moderate antibacterial and antifungal activity.

Human-Environment Interactions Shape Mosquito Seasonal Population Dynamics.

Mosquito species, including the Asian tiger mosquito, can transmit disease-causing pathogens such as dengue, Zika, and chikungunya, with their population dynamics influenced by a variety of factors including climate shifts, human activity, and local environmental conditions. Understanding these dynamics is vital for effective control measures. Our study, conducted in Jardí Botanic Marimurtra from May to November 2021, monitored Ae. albopictus activity using BG-Traps and investigated larval control effects. We employed Generalized Linear Mixed Models to analyze variables like weather, human presence, and larvicidal control on adult mosquito abundance. Adults of Ae. albopictus exhibited a seasonal pattern influenced by temperature but with bimodal peaks linked to cumulative rainfall. Proximity to stagnant water and visitor influx directly affected mosquito captures. Additionally, the effectiveness of larvicide treatments depended on interactions between preceding rainfall levels and treatment timing. Our research emphasizes the significance of studying vector ecology at local scales to enhance the efficacy of control programs and address the escalating burden of vector-borne diseases. Considering the impacts of extreme weather events and climate shifts is essential for the development of robust vector control strategies. Furthermore, our distinct findings serve as a prime illustration of utilizing statistical modeling to gain mechanistic insights into ecological patterns and processes.

Next-generation neuropeptide Y receptor small-molecule agonists inhibit mosquito-biting behavior

BackgroundFemale Aedes aegypti mosquitoes can spread disease-causing pathogens when they bite humans to obtain blood nutrients required for egg production. Following a complete blood meal, host-seeking is suppressed until eggs are laid. Neuropeptide Y-like receptor 7 (NPYLR7) plays a role in endogenous host-seeking suppression and previous work identified small-molecule NPYLR7 agonists that inhibit host-seeking and blood-feeding when fed to mosquitoes at high micromolar doses.MethodsUsing structure–activity relationship analysis and structure-guided design we synthesized 128 compounds with similarity to known NPYLR7 agonists.ResultsAlthough in vitro potency (EC50) was not strictly predictive of in vivo effect, we identified three compounds that reduced blood-feeding from a live host when fed to mosquitoes at a dose of 1 μM—a 100-fold improvement over the original reference compound.ConclusionsExogenous activation of NPYLR7 represents an innovative vector control strategy to block mosquito biting behavior and prevent mosquito–human host interactions that lead to pathogen transmission.Graphical

Biogenic iron oxide nanoparticles (Fe2O3 NPs) adeptly diminish leaf blight of Rosa chinensis by exhibiting higher expression of RcWRKY29 and increasing antioxidant enzymatic activities

Rose (Rosa chinensis) is subjected to various biotic and abiotic stresses. In this study, rose leaves with blight symptoms were collected and based on microscopic, morphological, and genetic analyses, the disease-causing pathogen was identified as Aspergillus niger. To our knowledge, this is the first report of leaf blight of R. chinensis in Pakistan. To control this disease, iron oxide nanoparticles (Fe2O3 NPs) were synthesized in the seed extract of Trachyspermum ammi. Suitable formation of synthesized Fe2O3 NPs was tested using reliable techniques. Fourier transformed infrared (FTIR) spectrum of Fe2O3 NPs determined the presence of reducing agent like alcohol, alkyl halide and amine on the surface of NPs. X-Ray diffraction (XRD) analysis depicted crystal-like nature and size (41 nm) of NPs, while scanning electron microscopy (SEM) depicted their spherical shape. Sharp Fe and O peaks were observed by energy dispersive X-ray (EDX) analysis. All concentrations of Fe2O3 NPs (0.25, 0.5, 0.75, 1 and 1.5 mg/ mL) inhibited mycelial growth, in vitro and the greatest inhibition (88.9 %) was observed at 1.0 mg/ mL concentration. SEM micrographs showed severe shrinking and structural decomposition of mycelia at this concentration. In pot experiment, Fe2O3 NPs adeptly controlled blight disease of rose leaves by improving various physiological and biochemical attributes and superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities. Findings of Real-Time Quantitative Reverse Transcription PCR (qRT-PCR) showed the higher expression of RcWRKY29 by the application of Fe2O3 NPs, depicting its probable role in plant defense mechanism. These results proved that the application of Fe2O3 NPs can efficiently prevent the spread of blight disease.

Hymenolepis diminuta infection in an adult's lung: a case report

Hymenolepis diminuta is a common parasite of rats and mice, but is very rare in humans with cases reported from various parts of the world. Here, we reported a case of Hymenolepis diminuta infection involving both the respiratory and digestive tracts in a 49-year-old male patient whose initial imaging and symptoms were strikingly similar to pneumonia. Since no disease-causing pathogens were found during routine examinations, we considered respiratory infection by specific pathogens before metagenomic next-generation sequencing of broncho-alveolar lavage fluid confirmed the diagnosis of Hymenolepis diminuta. After confirming the diagnosis, we retested the patient's stool repeatedly and found Hymenolepis diminuta eggs finally. To help doctors better understand this condition and avoid misdiagnosis, this article provided a summary of the clinical characteristics, diagnostic techniques, and therapeutic options for infection by Hymenolepis diminuta.

Review of Antifungal Resistance in West Africa

Knowledge of local and regional antimicrobial resistance (AMR) is important for clinical decision-making. However, surveillance capacity for fungal infections let alone antifungal resistance is lacking throughout West Africa, and current antifungal resistance data are sparse. We sought to address this gap by summarizing all available high-quality data on antifungal resistance in West Africa. We searched the PubMed database, African Journals Online archives, and free web searches in October and December 2023 using the terms "antifungal resistance" and "West Africa" to find articles published from 2010 onwards. Only 11 articles were included in our analysis most of which were cross-sectional and descriptive in design; relatively high levels of antifungal resistance (AFR) to commonly used antifungals were reported including (24-75%) resistance to fluconazole and ketoconazole, two of the most frequently-prescribed antifungals in this region. There is a high level of resistance to griseofulvin, ketoconazole, cotrimoxazole, and fluconazole among dermatophyte infections (80-100%) with 100% resistance to amphotericin B, ketoconazole, and fluconazole reported by the invasive fungal disease-causing pathogen Cryptococcus neoformans. Resistance to commonly used anti-fungal drugs is prevalent; raising concern that these drugs may no longer be useful for treating moderate or severe fungal infections in West Africa hence calling for countries to promote acceptance of antimicrobial stewardship as a programmatic strategy not just focused on bacterial resistance but also fungal resistance including pharmacy management, laboratory complete mycological investigations and dissemination of standard fungal susceptibility profiles.

Tick distribution and comparative analysis of bovine blood microbiome in two provinces of South Africa using 16S rRNA PacBio sequencing approach

IntroductionTicks are obligate ectoparasites recognized worldwide as major vectors of several disease-causing pathogens and are good indicators of disease distribution and epidemiology. Recent years have seen a growing concern regarding emerging and re-emerging of economically important tick-borne pathogens of livestock and humans worldwide. The overall objective of the study was to give an insight into current tick distribution and associated bacterial pathogens that may pose a threat to cattle in the sampled study sites.MethodsA total of 150 cattle were randomly selected from three study sites, Harrismith and Phuthaditjhaba in Free State Province and Bergville in KwaZulu Natal Province, South Africa. Blood samples were collected from the cattle and DNA was subjected to the 16S rRNA gene microbiome sequencing on the circular consensus PacBio sequencing platform. Ticks were also collected from various predilection sites of the sampled animals.ResultsA total of eight tick species were identified and Rhipicephalus evertsi evertsi (79.4%) was the most abundant followed by R. appendiculatus (11.7%), R. afranicus (2.6%), R. simus (2.6%), Hyalomma rufipes (1.2%), R. decoloratus (1.0%), H. truncatum (0.7%) and R. microplus (0.7%). The bacterial microbiome sequence analysis revealed up to 16 phyla and 30 classes in the three study sites. Proteobacteria was the most dominant bacterial phyla with a relative abundance of 67.2% (Bergville), 73.8% (Harrismith) and 84.8% (Phuthaditjhaba), followed by Firmicutes at 9.6% (Phuthaditjhaba), 18.9% (Bergville) and 19.6% (Harrismith).Conclusion and perspectivesThe Chao 1 index estimator revealed significant differences in the α-diversity of microbial communities among three study sites. This study expands the knowledge on tick fauna and microbial communities in the three study sites.

Pyricularia pennisetigena as leaf blast disease-causing pathogen in king grass (Pennisetum sinese) and its assessment of the pathogenic risk

Pyricularia pennisetigena as leaf blast disease-causing pathogen in king grass (Pennisetum sinese) and its assessment of the pathogenic risk

Preferences for livestock bedding as a development substrate of the stable fly, Stomoxys calcitrans L. (Diptera: Muscidae), and potential application of entomopathogenic nematodes for controlling stable fly larvae.

The stable fly, Stomoxys calcitrans L. (Diptera: Muscidae), is a significant insect pest with global veterinary implications due to its capacity to both cause nuisance and transmit disease-causing pathogens to livestock. This study aimed to determine the livestock bedding preferred for use as a development substrate by S. calcitrans larvae and field-collected adults. The result showed that S. calcitrans larvae exhibited a preference (26.7%) for 7-day-old cow manure. Gravid females displayed a pronounced preference (55.0%) for fresh cow manure. As there were eight choices, indifference would result in 12.5% for each bedding substrate. Furthermore, the efficacy of four entomopathogenic nematodes (EPNs), namely Heterorhabditis bacteriophora (Poinar), Heterorhabditis indica Poinar, Karunakar & David (Rhabditida: Heterorhabditidae), Steinernema siamkayai Poinar, Karunakar & David and Steinernema carpocapsae (Weiser) (Rhabditida: Steinernematidae), against S. calcitrans larvae and the persistence after application to livestock bedding substrates were evaluated under laboratory conditions. In filter paper bioassays, all four EPNs caused 76.7%-100.0% mortality in the second instar larvae of S. calcitrans when applied at 50 and 100 infective juveniles (IJs)/cm2 within 5 days after exposure. For the third instar larvae of S. calcitrans, only H. indica induced high mortalities of 86.6% when applied at 100 IJs/cm2 within 5 days after exposure, while the other EPNs resulted in mortalities of less than 70%. The data further demonstrated that H. bacteriophora, H. indica and S. siamkayai remained present in the substrates linked to S. calcitrans larvae for as long as 7 days after the application of EPNs. This study demonstrates the potential of EPNs as a biologically based control agent against larvae of S. calcitrans, a serious pest and significant vector for various livestock animals.

Sensitivity Analysis and Optimal Control of Cocoa Black Pod Disease Caused by Phytophora Margakarya

To address the critical threat black pod disease poses to global cocoa production and farmer income, this study developed a novel mathematical model that utilizes a system of ordinary differential equations to capture the interactions between various stages of cocoa pods (susceptible cherelles, young/mature pods, ripe pods) and their disease state (exposed, infected). Additionally, the model incorporates the dynamics of the disease-causing pathogen population. Employing Pontryagin's Maximum Principle, the model optimizes control strategies that minimize disease impact. This optimization identifies the efficient allocation of resources, timing of interventions, and deployment of control measures like infected pod removal, fungicides, and sanitation practices. The finding of the study reveals that control measure u3 which is rouging (pod removal) and any one of the remaining control measures is best for the treatment of cocoa black pod disease caused by Phytophora Megarkaya. These findings translate into valuable, data-driven recommendations for cocoa farmers and disease management professionals. By strategically combining infected pod removal, targeted fungicide use, and environmental management practices, farmers can significantly reduce disease severity, enhance cocoa production, and promote a more sustainable cocoa industry.

In Vitro and In Silico Characterization of N-Formylated Two-Peptide Bacteriocin from Enterococcus faecalis CAUM157 with Anti-Listeria Activity.

Enterococcus faecalis CAUM157 (KACC 81148BP), a Gram-positive bacteria isolated from raw cow's milk, was studied for its bacteriocin production. The antimicrobial activity of CAUM157 was attributed to a two-peptide class IIb bacteriocin with potent activity against food-borne pathogen Listeria monocytogenes and periodontal disease-causing pathogens (Prevotella intermedia KCTC 15693T and Fusobacterium nucleatum KCTC 2488T). M157 bacteriocins exhibit high temperature and pH stability and resist hydrolytic enzyme degradation and detergent denaturation, potentially due to their structural conformation. Based on amino acid sequence, M157A and M157B were predicted to be 5.176kDa and 5.182kDa in size, respectively. However, purified bacteriocins and chemically synthesized N-formylated M157 peptides both showed 5.204kDa (M157A) and 5.209kDa (M157B) molecular mass, confirming the formylation of the N-terminal methionine of both peptides produced by strain CAUM157. Furthermore, the strain demonstrated favorable growth and fermentation with minimal bacteriocin production when cultured in whey-based media, whereas a 1.0% tryptone or soytone supplementation resulted in higher bacteriocin production. Although Ent. faecalis CAUM157 innately harbors genes for virulence factors and antimicrobial resistance (e.g., tetracycline and erythromycin), its bacteriocin production is valuable in circumventing the need for live microorganisms, particularly in food applications for pathogen control.