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1
Bannister, Stephanie, Stephen Kidd, Elizabeth Kirby, et al. "Development and Assessment of a Diagnostic DNA Oligonucleotide Microarray for Detection and Typing of Meningitis-Associated Bacterial Species." High-Throughput 7, no. 4 (2018): 32. http://dx.doi.org/10.3390/ht7040032.
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Meningitis is commonly caused by infection with a variety of bacterial or viral pathogens. Acute bacterial meningitis (ABM) can cause severe disease, which can progress rapidly to a critical life-threatening condition. Rapid diagnosis of ABM is critical, as this is most commonly associated with severe sequelae with associated high mortality and morbidity rates compared to viral meningitis, which is less severe and self-limiting. We have designed a microarray for detection and diagnosis of ABM. This has been validated using randomly amplified DNA targets (RADT), comparing buffers with or without formamide, in glass slide format or on the Alere ArrayTubeTM (Alere Technologies GmbH) microarray platform. Pathogen-specific signals were observed using purified bacterial nucleic acids and to a lesser extent using patient cerebral spinal fluid (CSF) samples, with some technical issues observed using RADT and glass slides. Repurposing the array onto the Alere ArrayTubeTM platform and using a targeted amplification system increased specific and reduced nonspecific hybridization signals using both pathogen nucleic and patient CSF DNA targets, better revealing pathogen-specific signals although sensitivity was still reduced in the latter. This diagnostic microarray is useful as a laboratory diagnostic tool for species and strain designation for ABM, rather than for primary diagnosis.
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Khaled, Alhomsi. "Study of Acute Bacterial Meningitis: Demographics, Symptoms and Signs." Chemistry Research Journal 5, no. 6 (2020): 21–24. https://doi.org/10.5281/zenodo.13147151.
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<strong>Abstract </strong><em>Objective: </em>This study aimed to determine the most common age, presentation (symptoms and signs) of acute bacterial meningitis (ABM) for each age group and the most common pathogens responsible for it. <em>Methods:</em> This is a retrospective study composed of all children (newborns until 12 years old) who reviewed clinics between 30/5/2018 and 21/3/2020 and were diagnosed with ABM. <em>Results: </em>This study included 50 patients. Most of the participants were boys between (1 month -6 months) old. The most common results of CSF culture in our study were sterile (25 cases of all patients). In addition, the most common pathogen was Streptococcus pneumoniae (13 cases of all patients). The most common symptom-sign for each age group (<month, 1 month-6 months, 6 months- 1 year, 1 year- 6 years and 6 years- 12 years) was poor breastfeeding-hyperreflexia, poor breastfeeding and convulsion equally-bulging fontanelle, fever- bulging fontanelle, fever- positive Neck Stiffness, upper Brudzinski, lower Brudzinski, Kernig equally and fever-neck stiffness, upper Brudzinski equally), respectively. <em>Conclusion: </em>We found that acute bacterial meningitis (ABM) is most common in boys between (1 month- 6 months) old. The most common pathogen causing ABM is streptococcus pneumoniae while the most common culture result was sterile.The mortality rate in our study was 21.8% (12 patients)
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Jamali, Yousef. "Modeling the Immune System Through Agent-based Modeling: A Mini-review." Immunoregulation 6, no. 1 (2024): 3–12. http://dx.doi.org/10.32598/immunoregulation.6.1.7.
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The immune system plays a critical role in protecting the human body against various pathogens and diseases. Understanding the complexity and dynamics of the immune system is essential for developing effective therapies and interventions. Agent-based modeling (ABM) has emerged as a powerful tool for simulating and studying the behavior of complex systems, including the immune system. This review examines the advantages, challenges, and applications of ABM in immune system modeling. ABM captures the complexity of immune cell behavior, spatial effects and stochasticity. It has been applied to study immune cell dynamics, immune responses to pathogens, immune cell migration, immunotherapies and immune system disorders. Challenges include parameterization, validation, and computational resource requirements. Future directions involve integrating multi-omics and single-cell data, incorporating machine learning, exploring multi-scale modeling, and developing user-friendly interfaces. ABM holds promise for enhancing our understanding of immune system dynamics and advancing diagnostics and treatments in immunology.
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Nwala, Chuks G., Oluchi M. Izuka, Ifeyinwa Roseann Chidomere, Ikechukwu Frank Ogbonna, Ichie Eziyi Kalu, and Ihuoma Kathleen Ukpabi. "Drug resistance profiling, antimicrobial susceptibility and demographic characteristics of children with acute bacterial meningitis in a Southeastern tertiary health facility." International Journal of Scientific Reports 10, no. 11 (2024): 392–98. http://dx.doi.org/10.18203/issn.2454-2156.intjscirep20243051.
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Background: Over the years, varying patterns of bacterial susceptibility and multidrug resistance (MDR) rates have been reported in different settings. Detailed evaluation of the drug profile of the bacterial pathogens implicated in children with invasive bacterial infection helps to reduce the heightened risk of adverse events that could follow poorly managed or complicated cases in resource limited environment like ours. This study therefore, aimed to highlight the antibiotic susceptibility and MDR rate, and establish the relationship if any, between demographic characteristics and positive CSF- bacterial isolates of post neonatal children with suspected acute bacterial meningitis (ABM). The findings would guide practitioners on the empirical antimicrobials to consider in the event of clinical suspicion of ABM pending the availability of CSF isolates' antibiogram. Methods: A prospective review of 100 children with clinical suspicion of ABM from January 2016- December 2020. Descriptive statistics, chi square and regression analysis were used to establish MDR rates, Isolates' susceptibility pattern and the relationship between demographic variables and positive isolates respectively. P<0.05 was accepted as significant. Results: Fluroquinolones, cephalosporins, imipenem and aminoglycosides were susceptible anti-microgram in children with ABM. Sixty-four (85.5%) of the isolates showed MDR pattern, and young children (infants and toddlers) were significantly associated with positive CSF bacterial isolates. Conclusions: ABM should be treated with combination of CNS penetrating empirical antibiotics due to rising rate of MDR pathogens. Young children with febrile illnesses should be thoroughly evaluated for possibility of CNS infection.
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Suryaminarsih, Penta, Tri Mujoko, K. Gusriyan, Fitri Wijayanti, and Salmah Mohammad. "Study of antibiosis of Streptomyces sp. from the land of shallot plants as biological agents of Fusariumsp. cause of Twisted diseases (Moler)." IOP Conference Series: Earth and Environmental Science 1131, no. 1 (2023): 012017. http://dx.doi.org/10.1088/1755-1315/1131/1/012017.
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Abstract The use of bio pesticides and organic pesticides from secondary metabolic filtrate of APH microorganisms is one of the food and horticulture cultivation technology packages which are the basis for this research objective. The research objective was to explore, isolate and identify of Streptomyces sp. in the land of shallot plants (Abm) and the antibiosis against the pathogens Fusariumsp cause of Moler shallot plant in vitro. Observer of Quality and quantity characteristics of secondary metabolites as antibiosis, The results showed that Streptomyces sp from land of shallot plant (Abm) isolates producing little antibiosis less able to inhibit the development of the pathogens Fusariumsp cause of Moler shallot plant in vitro. The identification of Actinomycetes spp. based on the morphology characteristic showed that Actinomycetes isolates are closely related with Streptomyces sp.
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Sarvepalli, Ajay Kumar, and Prakash Kalakappa Dharana. "Clinical profile, bacterial profile and outcomes of acute bacterial meningitis in a tertiary care hospital– one year study." International Journal of Advances in Medicine 4, no. 2 (2017): 502. http://dx.doi.org/10.18203/2349-3933.ijam20171050.
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Background: Bacterial meningitis is still one of the major causes of mortality and morbidity among all groups in developing countries. The mortality and prevalence of common pathogens has reduced in developing countries with implementation of successful vaccination against the pathogens. Laboratory surveillance of pathogens is crucial in formulating the empirical treatment guidelines and to identify the targets of immunization. The present study was undertaken to evaluate the clinical profile, bacterial pathogens and their antibiotic sensitivity pattern of the pathogens. The outcome of the cases was recorded and followed for six months to detect any neurological sequelae.Methods: A one year prospective cross sectional study was done and all suspected cases of acute bacterial meningitis (ABM) were screened and confirmed by diagnostic criteria. Clinical features were recorded and entered into the case sheet. CSF culture was done and biochemical analysis and cell counts were performed. All the data was entered in Microsoft excel and analysed.Results: A total of 547 cases were screened and 282 confirmed with 164 males and 116 females. 282 pathogens were isolated with 266 bacterial and 12 fungal isolates. Gram negative bacterial pathogens were predominant than gram positive. Streptococcus pneumoniae was the common isolate in the study followed by others like S. aureus, Coagulase negative staphylococci and Acinetobacter sp., Escherichia coli, Klebsiella pneumoniae and meningococci. Candida albicans and Cryptococcus sp. were fungal pathogens. Community acquired meningitis was commonest cause and seen in 51-60 years of age. Gram positive pathogens exhibited maximum sensitivity to vancomycin and linezolid whereas Gram negative pathogens to carbapenems.Conclusions: There is an overwhelming need to formulate policies in the management of cases of ABM. The rationale use of antibiotics is necessary to prevent the development of antibiotic resistance. Hence minimizing the emergence of antibiotic resistance and its spread is necessary, which can be achieved by regular prevalence and antibiotic susceptibility studies.
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Heinzen, Robert A., Scott S. Grieshaber, Levi S. Van Kirk, and Clinton J. Devin. "Dynamics of Actin-Based Movement byRickettsia rickettsii in Vero Cells." Infection and Immunity 67, no. 8 (1999): 4201–7. http://dx.doi.org/10.1128/iai.67.8.4201-4207.1999.
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ABSTRACT Actin-based motility (ABM) is a virulence mechanism exploited by invasive bacterial pathogens in the genera Listeria,Shigella, and Rickettsia. Due to experimental constraints imposed by the lack of genetic tools and their obligate intracellular nature, little is known about rickettsial ABM relative toListeria and Shigella ABM systems. In this study, we directly compared the dynamics and behavior of ABM ofRickettsia rickettsii and Listeria monocytogenes. A time-lapse video of moving intracellular bacteria was obtained by laser-scanning confocal microscopy of infected Vero cells synthesizing β-actin coupled to green fluorescent protein (GFP). Analysis of time-lapse images demonstrated that R. rickettsii organisms move through the cell cytoplasm at an average rate of 4.8 ± 0.6 μm/min (mean ± standard deviation). This speed was 2.5 times slower than that of L. monocytogenes, which moved at an average rate of 12.0 ± 3.1 μm/min. Although rickettsiae moved more slowly, the actin filaments comprising the actin comet tail were significantly more stable, with an average half-life approximately three times that of L. monocytogenes (100.6 ± 19.2 s versus 33.0 ± 7.6 s, respectively). The actin tail associated with intracytoplasmic rickettsiae remained stationary in the cytoplasm as the organism moved forward. In contrast, actin tails of rickettsiae trapped within the nucleus displayed dramatic movements. The observed phenotypic differences between the ABM of Listeria andRickettsia may indicate fundamental differences in the mechanisms of actin recruitment and polymerization.
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Rastogi, M., M. Kumar, A. Trivedi, and D. Rastogi. "CLINICAL PRESENTATION OF ACUTE BACTERIAL MENINGITIS ANDC.S.F. ANALYSIS OF ATTENDING OPDPATIENTS IN A TERTIARY CARE HOSPITAL KANPUR, INDIA." International Journal of Advanced Research 12, no. 05 (2024): 612–17. http://dx.doi.org/10.21474/ijar01/18760.
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Background:Meningitis is an infection of the Meninges. Generally caused by Viral, Bacterial and Fungal Pathogens. Viral Meningitis is less severe and heals without specific treatment whereas Acute Bacterial Meningitis (ABM) can be relatively severe and affect in internal illness. Acute Bacterial Meningitis (ABM) is a prime reason for loss of life and incapacity worldwide. Aim of this study is play important role in the diagnosis and more accurate treatment of patient. Method:In this study, all age groups were enrolled at one tertiary care hospital between November 2022 and April 2024. A total of 147 CSF clinically suspected Meningitis samples were submitted for analysis. Result:During the study, A total of 147 CSF samples were studied. Of these, 18 were identified as bacterial meningitis on the basis of Grams staining and cultures, with an Incidence of (12.24%). Acute bacterial meningitis was more frequent in paediatric patients than in adults. Gram-positive bacteria were the most common Organism, accounting for (77.77%) of the total.The male and female ratio among all Culture Positive cases was (1.57:1).
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Krisanapan, Pajaree, and Romanee Chaiwarith. "Time to blood cultures positivity of microorganisms using a continuous-monitoring automated blood cultures system." Asian Biomedicine 13, no. 2 (2019): 61–69. http://dx.doi.org/10.1515/abm-2019-0041.
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Abstract Background Previous studies showed that clinically significant pathogens were detected within 3 days of incubation using a continuous monitoring automated blood culture instrument. Objectives To determine time to blood culture positivity (TTP) of microorganisms using a BD BACTEC™ FX. Methods A cross-sectional study was conducted at Maharaj Nakorn Chiang Mai Hospital, Thailand from October to November 2014. Results One-hundred and eighty-one patients with 195 episodes of infection and 436 cultures were included in the analysis. Among 181 patients, 55.2% were male and the median age was 61 years (interquartile range (IQR) 50, 76). Of the 195 episodes of infections, the most common source was genitourinary tract (15.4%). Overall, the median TTP was 17 hours (IQR 11.5, 24.5), the shortest TTP was observed in Streptococcus agalactiae. Four-hundred and seventy-eight cultures (97.6%) and all (100%) were detected at 3 days and 5 days of incubation. Factors associated with TTP ≤24 hour were blood drawn from patients who had hematologic malignancy (odds ratio (OR) 9.6, 95% confidence interval (CI) 1.2, 74.3, P = 0.030), endocarditis and vascular infection (OR 8.7, 95% CI 1.1, 67.2, P = 0.038), thrombocytopenia (OR 2.4, 95% CI 1.3, 4.4, P = 0.004), clinical of systemic inflammatory response syndrome (SIRS) (OR 2.3, 95% CI 1.2, 4.5, P = 0.014), and not receiving antimicrobials within 72 hours before cultures taken (OR 2.2, 95% CI 1.4, 3.6, P < 0.001). Conclusions TTP varied depends upon the pathogens and clinical settings. However, bacteria were isolated from almost, but not all of the blood cultures within 3 days of incubation.
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Bagudo, Ahmad Ibrahim, Godwin Attah Obande, Azian Harun, and Kirnpal Kaur Banga Singh. "Advances in automated techniques to identify Acinetobacter calcoaceticus–Acinetobacter baumannii complex." Asian Biomedicine 14, no. 5 (2020): 177–86. http://dx.doi.org/10.1515/abm-2020-0026.
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AbstractAcinetobacter species, particularly those within Acinetobacter calcoaceticus–A. baumannii complex (ACB complex), have emerged as clinically relevant pathogens in hospital environments worldwide. Early and quick detection and identification of Acinetobacter infections is challenging, and traditional culture and biochemical methods may not achieve adequate levels of speciation. Moreover, currently available techniques to identify and differentiate closely related Acinetobacter species are insufficient. The objective of this review is to recapitulate the current evolution in phenotypic and automated techniques used to identify the ACB complex. Compared with other automated or semiautomated systems of bacterial identification, matrix-assisted laser desorption–ionization time-of-flight mass spectrometry (MALDI-TOF MS) demonstrates a high level of Acinetobacter species identification and discrimination, including newly discovered species A. seifertii and A. dijkshoorniae.
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Baker, Kelly K., Sheillah Simiyu, Phylis Busienei, et al. "Protocol for the PATHOME study: a cohort study on urban societal development and the ecology of enteric disease transmission among infants, domestic animals and the environment." BMJ Open 13, no. 11 (2023): e076067. http://dx.doi.org/10.1136/bmjopen-2023-076067.
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IntroductionGlobal morbidity from enteric infections and diarrhoea remains high in children in low-income and middle-income countries, despite significant investment over recent decades in health systems and water and sanitation infrastructure. Other types of societal development may be required to reduce disease burden. Ecological research on the influence of household and neighbourhood societal development on pathogen transmission dynamics between humans, animals and the environment could identify more effective strategies for preventing enteric infections.Methods and analysisThe ‘enteric pathome’—that is, the communities of viral, bacterial and parasitic pathogens transmitted from human and animal faeces through the environment is taxonomically complex in high burden settings. This integrated cohort-exposure assessment study leverages natural socioeconomic spectrums of development to study how pathome complexity is influenced by household and neighbourhood infrastructure and hygiene conditions. We are enrolling under 12-month-old children in low-income and middle-income neighbourhoods of two Kenyan cities (Nairobi and Kisumu) into a ‘short-cohort’ study involving repeat testing of child faeces for enteric pathogens. A mid-study exposure assessment documenting infrastructural, behavioural, spatial, climate, environmental and zoonotic factors characterises pathogen exposure pathways in household and neighbourhood settings. These data will be used to inform and validate statistical and agent-based models (ABM) that identify individual or combined intervention strategies for reducing multipathogen transmission between humans, animals and environment in urban Kenya.Ethics and disseminationThe protocols for human subjects’ research were approved by Institutional Review Boards at the University of Iowa (ID-202004606) and AMREF Health Africa (ID-ESRC P887/2020), and a national permit was obtained from the Kenya National Commission for Science Technology and Innovation (ID# P/21/8441). The study was registered on Clinicaltrials.gov (Identifier:NCT05322655) and is in pre-results stage. Protocols for research on animals were approved by the University of Iowa Animal Care and Use Committee (ID 0042302).
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Loganathan, Archana, Prasanth Manohar, Kandasamy Eniyan, Rama Jayaraj, and Ramesh Nachimuthu. "Evaluation of various phenotypic methods with genotypic screening for detection of methicillin-resistant Staphylococcus aureus." Asian Biomedicine 13, no. 6 (2020): 225–33. http://dx.doi.org/10.1515/abm-2019-0065.
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AbstractBackgroundStaphylococcus aureus is one of the common opportunistic gram-positive pathogens which are often associated with nosocomial infections. Detection of methicillin-resistant S. aureus (MRSA) has become complicated due to the complex phenotypic and genomic pattern.ObjectiveTo evaluate the sensitivity and specificity pattern of various phenotypic methods used in screening mec genes harboring MRSA.MethodsClinical isolates of S. aureus were collected from diagnostic centers in Tamil Nadu. Phenotypic identification methods such as Minimal Inhibitory Concentration for oxacillin, oxacillin screen agar (OSA), oxacillin disk diffusion, and cefoxitin disk diffusion (CFD) tests were compared. The clinical isolates were classified into MRSA and methicillin-susceptible S. aureus (MSSA) based on the polymerase chain reaction (PCR) amplification of the mecA gene.ResultOut of 50 S. aureus, 21 were found to be MRSA based on the presence of the mecA gene. All 21 mecA-positive isolates were found to be resistant through minimum inhibitory concentration (MIC) and CFD test, having a sensitivity of 100% and specificity of 52% and 62%, respectively. OSA and oxacillin disk tests were found to have a sensitivity of 86% and specificity of 48% and 52%, respectively.ConclusionThe combination of two phenotypic methods, CFD and oxacillin MIC, can be used for the detection of MRSA in clinical laboratories.
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Conceição, Cinara Souza da, Barbara Victor Souza, Jessica Manya Bittencourt Dias Vieira, and Janaína dos Santos Nascimento. "Pathogen killing pathogen: antimicrobial substance from Acinetobacter active against foodborne pathogens." Journal of Infection in Developing Countries 12, no. 05 (2018): 297–304. http://dx.doi.org/10.3855/jidc.9894.
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Introduction: Antimicrobial substances (AMS) produced by bacteria may reduce or prevent the growth of pathogenic and spoilage microorganisms in food. In this study, 16 isolates of Acinetobacter baumannii/calcoaceticus (ABC) complex, previously obtained from reconstituted infant milk formula (IMF) samples and the preparation and distribution utensils from the nursery of a public hospital, were used to screen for AMS production.
 Methodology: Antimicrobial substance production and spectrum of activity assays were performed by agar-spot assay. Optimization of growth conditions for AMS production was also evaluated.
 Results: Three (17.6%) isolates, namely JE3, JE4, and JE6, produced AMS against the principal indicator strain Salmonella enterica subsp. enterica serotype Typhi ATCC 19214. JE6 was also able to inhibit strains of Klebsiella pneumoniae, Proteus vulgaris, and Bacillus cereus, a Gram-positive bacteria. Remarkably, JE6 was able to inhibit all the tested resistant and multidrug-resistant (MDR) strains of the ABC complex and Shigella dysenteriae associated with IMF and utensils, indicating a potentially valuable application. AMS produced by JE6 does not appear to be affected by proteolytic enzymes and the producer strain showed specific immunity to its own AMS.
 Conclusion: This study highlights AMS produced by Acinetobacter with applications against MDR spoilage and foodborne pathogens - some of them, infectious disease causing agents - which, to our knowledge, has not been previously described.
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Constant, Zébré Arthur, Tiekoura Konan Bertin, Coulibaly Bakary, et al. "Evaluation of Antimicrobial Efficacy of Hydrazide-Hydrazone Derivatives against Food Borne Pathogens." Microbiology Research Journal International 34, no. 7 (2024): 23–31. http://dx.doi.org/10.9734/mrji/2024/v34i71455.
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Bacteria are a real public health problem because of their involvement in many diseases. Their resistance to antibiotics has become one of the most important problems in the fight against infectious diseases worldwide. The objective of this work was to evaluate the antibacterial activity of hydrazide-hydrazone derivatives against pathogenic strains isolated from food using the agar diffusion method in cups and the macro-dilution method in liquid medium. In this work, a survey was conducted among food vendors on the four security corridors of the city of Daloa. A structured questionnaire was administered to 127 vendors and a total of 60 food samples were collected from the four corridors and analysed. The results indicate that the majority of food sales at these security corridors are carried out by women (88.12%). The vendors were mostly adults (59.84%) aged between 15 and 35, with no formal education (50.39%). Microbiological analysis of the 2 types of food showed the presence of enterobacteria above the recommended thresholds. Concerning the antimicrobial effectiveness explored, four substances (AEV5, AB2, AB3 and AB5) revealed antibacterial activity. The MBC/MIC ratio of all these substances being less than 4 indicates that these synthesised substances all have bactericidal activity. As a result, substances derived from S-alkylation and Mannich bases can be used to combat bacterial infections.
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Asselbergh, Bob, David De Vleesschauwer, and Monica Höfte. "Global Switches and Fine-Tuning—ABA Modulates Plant Pathogen Defense." Molecular Plant-Microbe Interactions® 21, no. 6 (2008): 709–19. http://dx.doi.org/10.1094/mpmi-21-6-0709.
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Plants are obliged to defend themselves against a wide range of biotic and abiotic stresses. Complex regulatory signaling networks mount an appropriate defense response depending on the type of stress that is perceived. In response to abiotic stresses such as drought, cold, and salinity, the function of abscisic acid (ABA) is well documented: elevation of plant ABA levels and activation of ABA-responsive signaling result in regulation of stomatal aperture and expression of stress-responsive genes. In response to pathogens, the role of ABA is more obscure and is a research topic that has long been overlooked. This article aims to evaluate and review the reported modes of ABA action on pathogen defense and highlight recent advances in deciphering the complex role of ABA in plant–pathogen interactions. The proposed mechanisms responsible for positive or negative effects of ABA on pathogen defense are discussed, as well as the regulation of ABA signaling and in planta ABA concentrations by beneficial and pathogenic microorganisms. In addition, the fast-growing number of reports that characterize antagonistic and synergistic interactions between abiotic and biotic stress responses point to ABA as an essential component in integrating and fine-tuning abiotic and biotic stress-response signaling networks.
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Tan, Leitao, Qiuping Liu, Yufeng Song, et al. "Differential Function of Endogenous and Exogenous Abscisic Acid during Bacterial Pattern-Induced Production of Reactive Oxygen Species in Arabidopsis." International Journal of Molecular Sciences 20, no. 10 (2019): 2544. http://dx.doi.org/10.3390/ijms20102544.
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Abscisic acid (ABA) plays important roles in positively or negatively regulating plant disease resistance to pathogens. Here, we reassess the role of endogenous and exogenous ABA by using: 35S::ABA2, a previously reported transgenic Arabidopsis line with increased endogenous ABA levels; aba2-1, a previously reported ABA2 mutant with reduced endogenous ABA levels; and exogenous application of ABA. We found that bacterial susceptibility promoted by exogenous ABA was suppressed in 35S::ABA2 plants. The 35S::ABA2 and aba2-1 plants displayed elevated and reduced levels, respectively, of bacterial flagellin peptide (flg22)-induced H2O2. Surprisingly, ABA pre-treatment reduced flg22-induced H2O2 generation. Exogenous, but not endogenous ABA, increased catalase activity. Loss of nicotinamide adenine dinucleotide phosphate oxidase genes, RBOHD and RBOHF, restored exogenous ABA-promoted bacterial susceptibility of 35S::ABA2 transgenic plants. In addition, endogenous and exogenous ABA had similar effects on callose deposition and salicylic acid (SA) signaling. These results reveal an underlying difference between endogenous and exogenous ABA in regulating plant defense responses. Given that some plant pathogens are able to synthesize ABA and affect endogenous ABA levels in plants, our results highlight the importance of reactive oxygen species in the dual function of ABA during plant-pathogen interactions.
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Goel, Ajay K., Derek Lundberg, Miguel A. Torres, et al. "The Pseudomonas syringae Type III Effector HopAM1 Enhances Virulence on Water-Stressed Plants." Molecular Plant-Microbe Interactions® 21, no. 3 (2008): 361–70. http://dx.doi.org/10.1094/mpmi-21-3-0361.
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Pseudomonas syringae strains deliver diverse type III effector proteins into host cells, where they can act as virulence factors. Although the functions of the majority of type III effectors are unknown, several have been shown to interfere with plant basal defense mechanisms. Type III effectors also could contribute to bacterial virulence by enhancing nutrient uptake and pathogen adaptation to the environment of the host plant. We demonstrate that the type III effector HopAM1 (formerly known as AvrPpiB) enhances the virulence of a weak pathogen in plants that are grown under drought stress. This is the first report of a type III effector that aids pathogen adaptation to water availability in the host plant. Expression of HopAM1 makes transgenic Ws-0 Arabidopsis hypersensitive to abscisic acid (ABA) for stomatal closure and germination arrest. Conditional expression of HopAM1 in Arabidopsis also suppresses basal defenses. ABA responses overlap with defense responses and ABA has been shown to suppress defense against P. syringae pathogens. We propose that HopAM1 aids P. syringae virulence by manipulation of ABA responses that suppress defense responses. In addition, host ABA responses enhanced by type III delivery of HopAM1 protect developing bacterial colonies inside leaves from osmotic stress.
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Nguyen, Ngoc Huu, Patricia Trotel-Aziz, Sandra Villaume, et al. "Bacillus subtilis and Pseudomonas fluorescens Trigger Common and Distinct Systemic Immune Responses in Arabidopsis thaliana Depending on the Pathogen Lifestyle." Vaccines 8, no. 3 (2020): 503. http://dx.doi.org/10.3390/vaccines8030503.
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Plants harbor various beneficial bacteria that modulate their innate immunity, resulting in induced systemic resistance (ISR) against various pathogens. However, the immune mechanisms underlying ISR triggered by Bacillus spp. and Pseudomonas spp. against pathogens with different lifestyles are not yet clearly elucidated. Here, we show that root drenching of Arabidopsis plants with Pseudomonas fluorescensPTA-CT2 and Bacillus subtilis PTA-271 can induce ISR against the necrotrophic fungus B. cinerea and the hemibiotrophic bacterium Pseudomonas syringae Pst DC3000. In the absence of pathogen infection, both beneficial bacteria do not induce any consistent change in systemic immune responses. However, ISR relies on priming faster and robust expression of marker genes for the salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) signaling pathways upon pathogen challenge. These responses are also associated with increased levels of SA, JA, and abscisic acid (ABA) in the leaves of bacterized plants after infection. The functional study also points at priming of the JA/ET and NPR1-dependent defenses as prioritized immune pathways in ISR induced by both beneficial bacteria against B. cinerea. However, B. subtilis-triggered ISR against Pst DC3000 is dependent on SA, JA/ET, and NPR1 pathways, whereas P. fluorescens-induced ISR requires JA/ET and NPR1 signaling pathways. The use of ABA-insensitive mutants also pointed out the crucial role of ABA signaling, but not ABA concentration, along with JA/ET signaling in primed systemic immunity by beneficial bacteria against Pst DC3000, but not against B. cinerea. These results clearly indicate that ISR is linked to priming plants for enhanced common and distinct immune pathways depending on the beneficial strain and the pathogen lifestyle.
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Nuzhnaya, T. V., A. V. Sorokan, S. V. Veselova, and I. V. Maksimov. "INFLUENCE OF PHYTOHORMONES ON THE COLONIES GROWTH AND THE DEGREE OF SPORRULATION OF DIFFERENT STAGONOSPORA NODORUM ISOLATES." ÈKOBIOTEH 6, no. 1 (2023): 1–13. http://dx.doi.org/10.31163/2618-964x-2023-6-1-1-13.
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Currently, the phytohormones cytokinins (CK) and abscisic acid (ABA) are considered as important regulators of the interaction between pathogens and plants. However, data on the role of these phytohormones in pathogenesis are contradictory, and information on the role of CK and ABA in the regulation of fungal growth and development is very limited. In this work, we studied the effects of CK and ABA on the growth of colonies and the degree of sporulation of various isolates of the pathogen Stagonospora nodorum SnB, Sn9MH-3A, and Sn4VD. The choice of phytohormone concentrations was carried out using the S. nodorum SnB isolate, and it was shown that the concentration of both CK and ABA, 0.1 µM, had the greatest effect on the sporulation of the fungus and inhibited the radial growth of the mycelium least of all. The addition of CK or ABA to the cultivation medium inhibited the growth of mycelium, but increased the sporulation of aggressive isolates of S. nodorum SnB and Sn9MH-3A. Moreover, the degree of influence of ABA on the sporulation of these isolates differed. The avirulent Sn4VD isolate increased its radial growth in the presence of the phytohormones CK and ABA, but did not begin to sporulate. Thus, the effect of CK and ABA on the growth of colonies and the degree of sporulation of the pathogen S. nodorum may be opposite and depend both on the concentration of phytohormones and on the genotype of the pathogen strain.
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Hirsch, Lou, Gabrielle Crouse, Gabrielle Scolpino, and Kari Peter. "An Apple a Day Keeps the Gray Mold Away." American Biology Teacher 86, no. 5 (2024): 300–306. http://dx.doi.org/10.1525/abt.2024.86.5.300.
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Most consumers dispose of rotten food without a second thought; however, they also throw away a dynamic group of plant pathogens that can be utilized for inquiry-driven investigations into host/pathogen interactions. Botrytis cinerea is a common necrotrophic fungus that can infect most plants but causes substantial losses to the grape and fresh berry industries. Because most store-bought strawberries eventually succumb to this pathogen (due to the presence of spores from the field or packing facility), they are a dependable source of fungal inoculum to test novel hypotheses about the nature of disease. Across the produce aisle, apples are a diverse, well-characterized, and susceptible host population that enables students to construct individualized experiments about the nature of disease with adequate replication for meaningful analysis. This experimental protocol will outline how to conduct an infection assay with B. cinerea and commercially available apple varieties for students to develop their own experiments, inoculate their own plants, and analyze their own data to answer important questions about how pathogens cause disease.
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Watkins, Richard R., Bin Du, Robin Isaacs, and David Altarac. "Pathogen-Targeted Clinical Development to Address Unmet Medical Need: Design, Safety, and Efficacy of the ATTACK Trial." Clinical Infectious Diseases 76, Supplement_2 (2023): S210—S214. http://dx.doi.org/10.1093/cid/ciad097.
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Abstract There is a crucial need for novel antibiotics to stem the tide of antimicrobial resistance, particularly against difficult to treat gram-negative pathogens like Acinetobacter baumannii-calcoaceticus complex (ABC). An innovative approach to addressing antimicrobial resistance may be pathogen-targeted development programs. Sulbactam-durlobactam (SUL-DUR) is a β-lactam/β-lactamase inhibitor combination antibiotic that is being developed to specifically target drug-resistant ABC. The development of SUL-DUR culminated with the Acinetobacter Treatment Trial Against Colistin (ATTACK) trial, a global, randomized, active-controlled phase 3 clinical trial that compared SUL-DUR with colistin for treating serious infections due to carbapenem-resistant ABC. SUL-DUR met the primary noninferiority endpoint of 28-day all-cause mortality. Furthermore, SUL-DUR had a favorable safety profile with a statistically significant lower incidence of nephrotoxicity compared with colistin. If approved, SUL-DUR could be an important treatment option for infections caused by ABC, including carbapenem-resistant and multidrug-resistant strains. The development program and the ATTACK trial highlight the potential for pathogen-targeted development programs to address the challenge of antimicrobial resistance.
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Nuzhnaya, T. V., A. V. Sorokan, S. V. Veselova, M. Yu Shein, and I. V. Maksimov. "The role of phytohormones in the regulation of expression of effector genes and specific transcription factors of Stagonospora nodorum in culture." Biomics 15, no. 2 (2023): 60–72. http://dx.doi.org/10.31301/2221-6197.bmcs.2023-9.
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The causative agent of wheat blotch the pathogenic fungus Stagonospora nodorum Berk. is one of the most harmful wheat pathogens. Necrotrophic effectors (NE) have been identified in the pathogen, which ensure the virulence of S. nodorum strains to the host plant, in the genome of which the dominant susceptibility gene corresponding to the effector is present. Currently, the study of the regulation of the genes expression responsible for virulence is becoming an increasingly important objective. Recently, the role of various transcription factors (TFs) in the regulation of effector genes expression in the fungal pathogens has been established. However, new data are emerging on the effect of hormones on the growth, development, and virulence of pathogenic fungi. Therefore, the aim of our research was to study the effect of cytokinins (CK) and abscisic acid (ABA) on the expression of the NE SnToxA, SnTox1, SnTox3, and TF SnStuA, SnPf2, and SnCon7 genes in various isolates of the pathogen S. nodorum SnB, Sn4VD, Sn9MN-3A, and Sn1SP, which differ in virulence. Our results showed that the intensity of NE and TF gene expression was associated with the aggressiveness of the pathogen isolate, and TF gene expression correlated with NE gene expression. The highest expression of NE genes was found in SnB and Sn1SP isolates. When the hormones ABA or CK were added to the cultivation medium, they mainly had a positive effect on the expression of the NE and TF genes. ABA treatment increased the expression of all three NE genes SnToxA, SnTox3, and SnTox1. Treatment with CK had a positive effect only on the expression of the SnTox3 gene. Based on the results, an assumption was made about the indirect effect of hormones on virulence factors through the regulation of growth and metabolism of fungi.
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Wu, Wenneng. "STRUCTURE AND FUNCTION OF THE FRUIT MICROBIOME IN HEALTHY AND DISEASED KIWIFRUIT." Pakistan Journal of Agricultural Sciences 56, no. 03 (2019): 577–85. http://dx.doi.org/10.21162/pakjas/19.8820.
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The fruit surface is an infection court where foodborne pathogens compete with indigenous microbiota for microsites to invade the fruits for nutrients acquisition. However, our current understanding of the structure and functions of fruit microbiome visa-vis postharvest pathogen infection is still nascent. Here, we sequenced the metagenomic DNA to understand the structural and functional attributes of healthy and diseased kiwifruit microbiome. The healthy fruits exhibited higher microbial diversity and distinct microbiome composition compared with diseased fruits. The microbiome of diseased fruit was dominated by fungal pathogens Neofusicoccum parvum and Diplodiaseriata, while the microbiome of healthy fruits were enriched by bacteria from Methylobacteriaceae, Sphingomonadaceae, Nocardioidaceae and fungi in Pleosporaceae. Importantly, the healthy fruit microbiome had a higher relative abundance of genes related to ABC transporter, two-component system, bacterial chemotaxis, bacterial secretion system, but had a lower relative abundance of genes associated with polycyclic aromatic hydrocarbon degradation, amino sugar and nucleotide sugar metabolism, glycine, serine and threonine metabolism compared with diseased fruits. Our results indicate that pathogen infection disrupts the fruit microbiome. The changes in microbiome composition and functions could also increase the possibility of secondary pathogen infection as the reduced microbial diversity may demonstrate less resistance to pathogens infection. Therefore, monitoring the microbiome dynamics and their functions using metagenomic approaches could be useful to build a predictive understanding of accurate postharvest disease diagnosis and management in the future
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Bian, Zhiyuan, Huanhuan Gao, and Chongying Wang. "NAC Transcription Factors as Positive or Negative Regulators during Ongoing Battle between Pathogens and Our Food Crops." International Journal of Molecular Sciences 22, no. 1 (2020): 81. http://dx.doi.org/10.3390/ijms22010081.
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The NAC (NAM, ATAF1/2, and CUC2) family of proteins is one of the largest plant-specific transcription factor (TF) families and its members play varied roles in plant growth, development, and stress responses. In recent years, NAC TFs have been demonstrated to participate in crop-pathogen interactions, as positive or negative regulators of the downstream defense-related genes. NAC TFs link signaling pathways between plant hormones, including salicylic acid (SA), jasmonic acid (JA), ethylene (ET), and abscisic acid (ABA), or other signals, such as reactive oxygen species (ROS), to regulate the resistance against pathogens. Remarkably, NAC TFs can also contribute to hypersensitive response and stomatal immunity or can be hijacked as virulence targets of pathogen effectors. Here, we review recent progress in understanding the structure, biological functions and signaling networks of NAC TFs in response to pathogens in several main food crops, such as rice, wheat, barley, and tomato, and explore the directions needed to further elucidate the function and mechanisms of these key signaling molecules.
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Mine, Akira, Matthias L. Berens, Tatsuya Nobori, et al. "Pathogen exploitation of an abscisic acid- and jasmonate-inducible MAPK phosphatase and its interception by Arabidopsis immunity." Proceedings of the National Academy of Sciences 114, no. 28 (2017): 7456–61. http://dx.doi.org/10.1073/pnas.1702613114.
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Phytopathogens promote virulence by, for example, exploiting signaling pathways mediated by phytohormones such as abscisic acid (ABA) and jasmonate (JA). Some plants can counteract pathogen virulence by invoking a potent form of immunity called effector-triggered immunity (ETI). Here, we report that ABA and JA mediate inactivation of the immune-associated MAP kinases (MAPKs), MPK3 and MPK6, in Arabidopsis thaliana. ABA induced expression of genes encoding the protein phosphatases 2C (PP2Cs), HAI1, HAI2, and HAI3 through ABF/AREB transcription factors. These three HAI PP2Cs interacted with MPK3 and MPK6 and were required for ABA-mediated MPK3/MPK6 inactivation and immune suppression. The bacterial pathogen Pseudomonas syringae pv. tomato (Pto) DC3000 activates ABA signaling and produces a JA-mimicking phytotoxin, coronatine (COR), that promotes virulence. We found that Pto DC3000 induces HAI1 through COR-mediated activation of MYC2, a master transcription factor in JA signaling. HAI1 dephosphorylated MPK3 and MPK6 in vitro and was necessary for COR-mediated suppression of MPK3/MPK6 activation and immunity. Intriguingly, upon ETI activation, A. thaliana plants overcame the HAI1-dependent virulence of COR by blocking JA signaling. Finally, we showed conservation of induction of HAI PP2Cs by ABA and JA in other Brassicaceae species. Taken together, these results suggest that ABA and JA signaling pathways, which are hijacked by the bacterial pathogen, converge on the HAI PP2Cs that suppress activation of the immune-associated MAPKs. Also, our data unveil interception of JA-signaling activation as a host counterstrategy against the bacterial suppression of MAPKs during ETI.
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Li, Shan, Pan Wu, Xiaofen Yu, et al. "Contrasting Roles of Ethylene Response Factors in Pathogen Response and Ripening in Fleshy Fruit." Cells 11, no. 16 (2022): 2484. http://dx.doi.org/10.3390/cells11162484.
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Fleshy fruits are generally hard and unpalatable when unripe; however, as they mature, their quality is transformed by the complex and dynamic genetic and biochemical process of ripening, which affects all cell compartments. Ripening fruits are enriched with nutrients such as acids, sugars, vitamins, attractive volatiles and pigments and develop a pleasant taste and texture and become attractive to eat. Ripening also increases sensitivity to pathogens, and this presents a crucial problem for fruit postharvest transport and storage: how to enhance pathogen resistance while maintaining ripening quality. Fruit development and ripening involve many changes in gene expression regulated by transcription factors (TFs), some of which respond to hormones such as auxin, abscisic acid (ABA) and ethylene. Ethylene response factor (ERF) TFs regulate both fruit ripening and resistance to pathogen stresses. Different ERFs regulate fruit ripening and/or pathogen responses in both fleshy climacteric and non-climacteric fruits and function cooperatively or independently of other TFs. In this review, we summarize the current status of studies on ERFs that regulate fruit ripening and responses to infection by several fungal pathogens, including a systematic ERF transcriptome analysis of fungal grey mould infection of tomato caused by Botrytis cinerea. This deepening understanding of the function of ERFs in fruit ripening and pathogen responses may identify novel approaches for engineering transcriptional regulation to improve fruit quality and pathogen resistance.
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Lan, Xingjie, Xiaoxia Wang, Quandan Tao, et al. "Activation of the VQ Motif-Containing Protein Gene VQ28 Compromised Nonhost Resistance of Arabidopsis thaliana to Phytophthora Pathogens." Plants 11, no. 7 (2022): 858. http://dx.doi.org/10.3390/plants11070858.
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Nonhost resistance refers to resistance of a plant species to all genetic variants of a non-adapted pathogen. Such resistance has the potential to become broad-spectrum and durable crop disease resistance. We previously employed Arabidopsis thaliana and a forward genetics approach to identify plant mutants susceptible to the nonhost pathogen Phytophthora sojae, which resulted in identification of the T-DNA insertion mutant esp1 (enhanced susceptibility to Phytophthora). In this study, we report the identification of VQ motif-containing protein 28 (VQ28), whose expression was highly up-regulated in the mutant esp1. Stable transgenic A. thaliana plants constitutively overexpressing VQ28 compromised nonhost resistance (NHR) against P. sojae and P. infestans, and supported increased infection of P. parasitica. Transcriptomic analysis showed that overexpression of VQ28 resulted in six differentially expressed genes (DEGs) that are involved in the response to abscisic acid (ABA). High performance liquid chromatography-mass spectrometry (HPLC-MS) detection showed that the contents of endogenous ABA, salicylic acid (SA), and jasmonate (JA) were enriched in VQ28 overexpression lines. These findings suggest that overexpression of VQ28 may lead to an imbalance in plant hormone homeostasis. Furthermore, transient overexpression of VQ28 in Nicotiana benthamiana rendered plants more susceptible to Phytophthora pathogens. Deletion mutant analysis showed that the C-terminus and VQ-motif were essential for plant susceptibility. Taken together, our results suggest that VQ28 negatively regulates plant NHR to Phytophthora pathogens.
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Klein, Cornelia, Karl Kuchler, and Martin Valachovic. "ABC proteins in yeast and fungal pathogens." Essays in Biochemistry 50 (September 7, 2011): 101–19. http://dx.doi.org/10.1042/bse0500101.
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All fungal genomes harbour numerous ABC (ATP-binding cassette) proteins located in various cellular compartments such as the plasma membrane, vacuoles, peroxisomes and mitochondria. Most of them have initially been discovered through their ability to confer resistance to a multitude of drugs, a phenomenon called PDR (pleiotropic drug resistance) or MDR (multidrug resistance). Studying the mechanisms underlying PDR/MDR in yeast is of importance in two ways: first, ABC proteins can confer drug resistance on pathogenic fungi such as Candida spp., Aspergillus spp. or Cryptococcus neoformans; secondly, the well-established genetic, biochemical and cell biological tractability of Saccharomyces cerevisiae makes it an ideal tool to study basic mechanisms of drug transport by ABC proteins. In the past, knowledge from yeast has complemented work on human ABC transporters involved in anticancer drug resistance or genetic diseases. Interestingly, increasing evidence available from yeast and other organisms suggests that ABC proteins play a physiological role in membrane homoeostasis and lipid distribution, although this is being intensely debated in the literature.
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Valenzuela, Alex H., Erica L. Mullins, and Antje Lauer. "Detecting a Fungal Pathogen in Its Natural Habitat: The Case of Valley Fever." American Biology Teacher 81, no. 7 (2019): 492–501. http://dx.doi.org/10.1525/abt.2019.81.7.492.
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Valley fever, a disease caused by the soilborne fungal pathogen Coccidioides spp., is on the rise in the southwestern United States and is suspected of expanding its habitat in response to climate change. Many people residing in endemic areas are unaware of the risk of contracting coccidioidomycosis by inhaling fugitive dust that may contain dormant arthroconidia of this fungus. In an effort to teach students about the ongoing epidemic of valley fever and reduce incidence of the disease through education, we developed an inquiry-based, multi-focus laboratory exercise that (1) increases awareness of valley fever incidence, disease symptoms, and ongoing efforts of disease prevention; (2) teaches about the pathogen's ecology; and (3) familiarizes students with molecular techniques targeting pathogen identification. This laboratory exercise uses polymerase chain reaction to detect Coccidioides spp. in DNA extracts from soil samples collected by students across different soil environments. Additionally, this exercise will teach students how to use publicly available data to investigate disease incidence over time and characterize soils the pathogen may inhabit.
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Schoonbeek, H., G. Del Sorbo, and M. A. De Waard. "The ABC Transporter BcatrB Affects the Sensitivity of Botrytis cinerea to the Phytoalexin Resveratrol and the Fungicide Fenpiclonil." Molecular Plant-Microbe Interactions® 14, no. 4 (2001): 562–71. http://dx.doi.org/10.1094/mpmi.2001.14.4.562.
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During pathogenesis, fungal pathogens are exposed to a variety of fungitoxic compounds. This may be particularly relevant to Botrytis cinerea, a plant pathogen that has a broad host range and, consequently, is subjected to exposure to many plant defense compounds. In practice, the pathogen is controlled with fungicides belonging to different chemical groups. ATP-binding cassette (ABC) transporters might provide protection against plant defense compounds and fungicides by ATP-driven efflux mechanisms. To test this hypothesis, we cloned BcatrB, an ABC transporter-encoding gene from B. cinerea. This gene encodes a 1,439 amino acid protein with nucleotide binding fold (NBF) and transmembrane (TM) domains in a [NBF-TM6]2 topology. The amino acid sequence has 31 to 67% identity with ABC transporters from various fungi. The expression of BcatrB is up regulated by treatment of B. cinerea germlings with the grapevine phytoalexin resveratrol and the fungicide fenpiclonil. BcatrB replacement mutants are not affected in saprophytic growth on different media but are more sensitive to resveratrol and fenpiclonil than the parental isolate. Furthermore, virulence of ΔBcatrB mutants on grapevine leaves was slightly reduced. These results indicate that BcatrB is a determinant in sensitivity of B. cinerea to plant defense compounds and fungicides.
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Posada-Vergara, Catalina, Stefan Vidal, and Michael Rostás. "Local Competition and Enhanced Defense: How Metarhizium brunneum Inhibits Verticillium longisporum in Oilseed Rape Plants." Journal of Fungi 9, no. 8 (2023): 796. http://dx.doi.org/10.3390/jof9080796.
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Metarhizium brunneum is a soil-borne fungal entomopathogen that can be associated with plant roots. Previous studies have demonstrated that root colonization by beneficial fungi can directly affect soil-borne pathogens through competition and antibiosis and can activate a systemic response in plants, resulting in a primed state for a faster and/or stronger response to stressors. However, the mechanisms by which Metarhizium inoculation ameliorates symptoms caused by plant pathogens are not well known. This study evaluated the ability of M. brunneum to protect oilseed rape (Brassica napus L.) plants against the soil-borne pathogen Verticillium longisporum and investigated whether the observed effects are a result of direct interaction and/or plant-mediated effects. In vitro and greenhouse experiments were conducted to measure fungal colonization of the rhizosphere and plant tissues, and targeted gene expression analysis was used to evaluate the plant response. The results show that M. brunneum delayed pathogen colonization of plant root tissues, resulting in decreased disease symptoms. Direct competition and antibiosis were found to be part of the mechanisms, as M. brunneum growth was stimulated by the pathogen and inhibited the in vitro growth of V. longisporum. Additionally, M. brunneum changed the plant response to the pathogen by locally activating key defense hormones in the salicylic acid (SA) and abscisic acid (ABA) pathways. Using a split-root setup, it was demonstrated that there is a plant-mediated effect, as improved plant growth and decreased disease symptoms were observed when M. brunneum was in the systemic compartment. Moreover, a stronger systemic induction of the gene PR1 suggested a priming effect, involving the SA pathway. Overall, this study sheds light on the mechanisms underlying the protective effects of M. brunneum against soil-borne pathogens in oilseed rape plants, highlighting the potential of this fungal entomopathogen as a biocontrol agent in sustainable agriculture.
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Alharbi, Metab, Abdulrahman Alshammari, Abdullah F. Alasmari, et al. "Designing of a Recombinant Multi-Epitopes Based Vaccine against Enterococcus mundtii Using Bioinformatics and Immunoinformatics Approaches." International Journal of Environmental Research and Public Health 19, no. 6 (2022): 3729. http://dx.doi.org/10.3390/ijerph19063729.
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Enterococcus species are an emerging group of bacterial pathogens that have a significant role in hospital-associated infections and are associated with higher mortality and morbidity rates. Among these pathogens, Enterococcus mundtii is one of the causative agents of multiple hospital associated infections. Currently, no commercially available licensed vaccine is present, and multi-drug resistant strains of the pathogen are prominent. Due to several limitations of experimental vaccinology, computational vaccine designing proved to be helpful in vaccine designing against several bacterial pathogens. Herein, we designed a multi-epitope-based vaccine against E. mundtii using in silico approaches. After an in-depth analysis of the core genome, three probable antigenic proteins (lytic polysaccharide monooxygenase, siderophore ABC transporter substrate-binding protein, and lytic polysaccharide monooxygenase) were shortlisted for epitope prediction. Among predicted epitopes, ten epitopes—GPADGRIAS, TTINHGGAQA, SERTALSVTT, GDGGNGGGEV, GIKEPDLEK, KQADDRIEA, QAIGGDTSN, EPLDEQTASR, AQWEPQSIEA, QPLKFSDFEL—were selected for multi-epitope vaccine construct designing. The screened B- and T-cell epitopes were joined with each other via specific linkers and linked to the cholera toxin B subunit as an adjuvant to enhance vaccine immune protection efficacy. The designed vaccine construct induced cellular and humoral immune responses. Blind docking with immune cell receptors, followed by molecular dynamic simulation results confirms the good binding potency and stability of the vaccine in providing protection against the pathogen.
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Al-Daoude, Antonious, Eyad Al-Shehadah, Amina Shoiab, Mohammed Jawhar, and Mohammed Imad Eddin Arabi. "Cooperative functioning of salicylic acid and phenylalanine ammonia lyase in barley plant challenged with spot blotch and powdery mildew diseases." Acta Biologica Szegediensis 63, no. 1 (2019): 31–36. http://dx.doi.org/10.14232/abs.2019.1.31-36.
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Salicylic acid (SA) and phenylalanine ammonia-lyase (PAL) have been suggested as important signals during plant resistance towards several fungal pathogens. In this work, to better understand the defense responses initiated by resistant and susceptible barley genotypes challenged with a necrotrophic (Cochliobolus sativus; Cs) and a biotrophic (Blumeria graminis; Bg) pathogens, the relative contributions of SA and PAL were investigated at early time points of infection. SA signaling was activated in both genotypes 24 hours post infection (hpi) as compared with the non-inoculated plants. However, with or without pathogen pretreatment, SA significantly increased (P = 0.001) in the resistant genotype that contained three-folds of total SA in comparison with the susceptible one for Bg. Reverse transcription-polymerase chain reaction (RTPCR) analysis revealed that PAL expression increases in the resistant and susceptible genotypes over the inoculation time points, with the maximum expression observed 48 hpi. PAL expression was paralleled by an increase in SA content in leaves as shown by the test coincidence (F3, 32 = 1.09, P = 0.49 for Cs and F3, 32 = 1.03, P = 0.48 for Bg). Results showed that the cooperatively function of SA and PAL in barley responses to both Cs and Bg appeared to be dependent on the plant genotype, and that SA signaling and PAL play a role in barley interactions with these both pathogens. This study might increase our understanding for a deeper molecular research on barley defense responses against pathogens with different lifestyles.
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Guardone, Lisa, Valentina Virginia Ebani, Ranieri Verin, et al. "Molecular Detection of Arthropod-Borne Pathogens in Eurasian Badgers (Meles meles) from the United Kingdom." Animals 10, no. 3 (2020): 446. http://dx.doi.org/10.3390/ani10030446.
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Arthropod-borne diseases (ABD) are of increasing interest in veterinary and public health. Eurasian badgers (Meles meles) are known to harbor a wide range of pathogens, but information on their role as ABD reservoirs and their potential epidemiological relevance is limited. This study aimed to investigate the occurrence of arthropod-borne pathogens, specifically piroplasmids and the bacteria Anaplasma phagocytophilum, Ehrlichia canis, Coxiella burnetii, Francisella tularensis and Bartonella spp., in badgers from Great Britain (GB). Blood and heart samples from 18 badgers were examined using PCR and sequencing. A neighbour-joining (NJ) phylogram was also produced. Nine animals tested positive for Babesia sp., while none of the samples was positive for the investigated bacteria. The sequences obtained clustered with other sequences of Babesia sp. from badgers from GB and elsewhere, including China, Hungary, Spain and Italy, showing a widespread distribution of this parasite in badgers. Badger-associated Babesia DNA was also found recently in a wild cat in Bosnia Herzegovina, in a wolf in Italy and in dogs in Hungary. Further investigations are needed to understand the epidemiology of this putative pathogen and its impact on the health of wild and domestic carnivores.
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Du, Hua-Ying, Yu-Zhou Zhang, Kuo Liu, et al. "Analysis of the Properties of 44 ABC Transporter Genes from Biocontrol Agent Trichoderma asperellum ACCC30536 and Their Responses to Pathogenic Alternaria alternata Toxin Stress." Current Issues in Molecular Biology 45, no. 2 (2023): 1570–86. http://dx.doi.org/10.3390/cimb45020101.
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ATP-binding cassette (ABC) transporters are involved in transporting multiple substrates, such as toxins, and may be important for the survival of Trichoderma when encountering biotic toxins. In this study, genome searching revealed that there are 44 ABC transporters encoded in the genome of Trichoderma asperellum. These ABC transporters were divided into six types based on three-dimensional (3D) structure prediction, of which four, represented by 39 ABCs, are involved in transport and the remaining two, represented by 5 ABCs, are involved in regulating translation. The characteristics of nucleotide-binding domain (NBD) are important in the identification of ABC proteins. Even though the 3D structures of the 79 NBDs in the 44 ABCs are similar, multiple sequence alignment showed they can be divided into three classes. In total, 794 motifs were found in the promoter regions of the 44 ABC genes, of which 541 were cis-regulators related to stress responses. To characterize how their ABCs respond when T. asperellum interact with fungi or plants, T. asperellum was cultivated in either minimal media (MM) control, C-hungry, N-hungry, or poplar medium (PdPap) to simulate normal conditions, competition with pathogens, interaction with pathogens, and interaction with plants, respectively. The results show that 17 of 39 transport ABCs are highly expressed in at least one condition, whereas four of the five translation-regulating ABCs are highly expressed in at least one condition. Of these 21 highly expressed ABCs, 6 were chosen for RT-qPCR expression under the toxin stress of phytopathogen Alternaria alternata, and the results show ABC01, ABC04, ABC05, and ABC31 were highly expressed and may be involved in pathogen interaction and detoxifying toxins from A. alternata.
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Cupertino, Marli do Carmo, Aloisio de Freitas Jorge Júnior, Guilherme Cabral Colares, et al. "A THERAPEUTIC APPROACH TO MENINGOENCEPHALITIS BY Streptococcus pneumoniae IN BRAZIL." Revista Contemporânea 4, no. 1 (2024): 2905–28. http://dx.doi.org/10.56083/rcv4n1-162.
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Introduction: Acute bacterial meningoencephalitis (ABM) are severe infections caused by microorganisms that are capable of reaching the meninges, as well as the brain. They areconsidered medical emergencies that require early diagnosis and immediate treatment. However, medical professionals have routinely encountered difficulties resulting from the Streptococcus pneumoniae’s antimicrobial resistance in the medical practice, becoming a public health problem in Brazil. The present article has the objective of revising literature and compiling data on S. pneumoniae’s resistance in ABM cases, with the intent of assisting the decision-making process on which therapy should be adopted. Methods: The study was conducted through the revision of literature regarding the treatment of ABM in humans published in the last 20 years, found in the PubMed/Medline, LILACS and SciELO digital databases. The first selection of articles was carried out by analyzing the titles and abstracts. The selected studies were read completely to determine their eligibility. Results and Discussions: The 45 selected articles described varying resistance of S. pneumoniae's to penicillin and ceftriaxone, which can reach approximately 50% to the first drug. The SIREVA Project (2016), developed in Brazil, deserves do to commended for being able to identify the following resistance patterns of the isolated pathogen in ABM cases: (1) 31,% to penicillins (sample of 334 patients), and (2) intermediate and high resistance to ceftriaxone, 6.9% and 5.6% respectively (sample of 320 patients). Despite the infrequent occurrence, present studies document the emergence of resistance mechanisms in pathogen strains to vancomycin. Nevertheless, the studies conducted in Brazil showed that the S. pneumoniae strains were completely sensitive to the previously mentioned drug. Conclusion: The association of ceftriaxone and vancomycin should be considered the best option to treat pneumococcal ABM in Brazil, due to the severity of the condition and the rising resistance of the pathogen to cephalosporins.
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Silva, Wallace Andrino da, Aline Macêdo Pinheiro, Leonam Gomes Coutinho, Luis Alberto Carneiro Marinho, and Lucymara Fassarella Agnez Lima. "Epidemiological profile of acute bacterial meningitis in the state of Rio Grande do Norte, Brazil." Revista da Sociedade Brasileira de Medicina Tropical 43, no. 4 (2010): 455–57. http://dx.doi.org/10.1590/s0037-86822010000400023.
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INTRODUCTION: Acute bacterial meningitis (ABM) remains a public health problem in Brazil. To evaluate the epidemiology of ABM cases at Giselda Trigueiro Hospital, Rio Grande do Norte, a descriptive retrospective survey was conducted covering 2005 to 2008. METHODS: Clinical and laboratory data were collected from the epidemiology department of the hospital and analyzed. RESULTS: Out of 168 ABM cases, 24.4%, 10.7%, and 2.4% were, respectively, caused by Streptococcus pneumoniae, Neisseria meningitidis and Haemophilus influenza b, and 5.4% by other bacteria. The mean age was 22.48 ± 18.7 years old. CONCLUSIONS: Streptococcus pneumoniae was the main causative pathogen in the young urban population.
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Cheng, Sau-Shan, Yee-Shan Ku, Ming-Yan Cheung, and Hon-Ming Lam. "AtGAP1 Promotes the Resistance to Pseudomonas syringae pv. tomato DC3000 by Regulating Cell-Wall Thickness and Stomatal Aperture in Arabidopsis." International Journal of Molecular Sciences 23, no. 14 (2022): 7540. http://dx.doi.org/10.3390/ijms23147540.
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GTP is an important signaling molecule involved in the growth, development, and stress adaptability of plants. The functions are mediated via binding to GTPases which are in turn regulated by GTPase-activating proteins (GAPs). Satellite reports have suggested the positive roles of GAPs in regulating ABA signaling and pathogen resistance in plants. However, the molecular mechanisms that bring forth the pathogen resistance have remained unclear. In this study, we demonstrated that the expression of AtGAP1 was inducible by Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). The overexpression of AtGAP1 in Arabidopsis promoted the expression of PR1 and the resistance to Pst DC3000. Proteomic analyses revealed the enhanced accumulation of cell-wall-modifying proteins as a result of AtGAP1 overexpression. By microscopic analyses, we showed that the overexpression of AtGAP1 resulted in increased thickness of the mesophyll cell wall and reduced stomatal aperture, which are effective strategies for restricting the entry of foliar pathogens. Altogether, we demonstrated that AtGAP1 increases the resistance to Pst DC3000 in Arabidopsis by promoting cellular strategies that restrict the entry of pathogens into the cells. These results point to a future direction for studying the modes of action of GAPs in regulating plant cell structures and disease resistance.
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Zhou, Yanyan, Huan Liu, Ting Wu, et al. "Screening of Reference Genes under Biotic Stress and Hormone Treatment of Mung Bean (Vigna radiata) by Quantitative Real-Time PCR." Genes 14, no. 9 (2023): 1739. http://dx.doi.org/10.3390/genes14091739.
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Mung bean (Vigna radiata) production has been greatly threatened by numerous diseases. Infection with these pathogens causes extensive changes in gene expression and the activation of hormone signal transduction. Quantitative real-time PCR (qRT-PCR) is the most common technique used for gene expression validation. Screening proper reference genes for mung bean under pathogen infection and hormone treatment is a prerequisite for ensuring the accuracy of qRT-PCR data in mung bean disease-resistance research. In this study, six candidate reference genes (Cons4, ACT, TUA, TUB, GAPDH, and EF1α) were selected to evaluate the expression stability under four soil-borne disease pathogens (Pythium myriotylum, Pythium aphanidermatum, Fusarium oxysporum, and Rhizoctonia solani) and five hormone treatments (SA, MeJA, ETH, ABA, and GA3). In the samples from different treatments, the Ct value distribution of the six candidate reference genes was different. Under the condition of hormone treatment, the Ct value ranged from a minimum of 17.87 for EF1α to a maximum of 29.63 for GAPDH. Under the condition of pathogen infection, the Ct value ranged from a minimum of 19.43 for EF1α to a maximum of 31.82 for GAPDH. After primer specificity analysis, it was found that GAPDH was not specific, so the five reference genes Cons4, ACT, TUA, TUB, and EF1α were used in subsequent experiments. The software products GeNorm, NormFinder, BestKeeper and RefFinder were used for qRT-PCR data analysis. In general, the best candidates reference genes were: TUA for SA, ABA, GA3, and Pythium myriotylum treatment; TUB for ETH treatment; ACT for MeJA and Fusarium oxysporum treatment; and EF1α for Pythium aphanidermatum and Rhizoctonia solani treatment. The most stably expressed genes in all samples were TUA, while Cons4 was the least stable reference gene. Finally, the reliability of the reference gene was further validated by analysis of the expression profiles of four mung bean genes (Vradi0146s00260, Vradi0158s00480, Vradi07g23860, and Vradi11g03350) selected from transcriptome data. Our results provide more accurate information for the normalization of qRT-PCR data in mung bean response to pathogen interaction.
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Garg, Ashok, Ashish Sharma, Sandhya Kumari, and Ambuj Shandil. "Clinical profile and outcome of pediatric bacterial meningitis: a prospective study from tertiary institute in Northern India." International Journal of Research in Medical Sciences 6, no. 8 (2018): 2739. http://dx.doi.org/10.18203/2320-6012.ijrms20183261.
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Background: Meningitis is one of the fatal infections occurring in infants and older children. In acute bacterial meningitis (ABM), inflammation of the leptomeninges is triggered by bacteria present in the subarachnoid space. ABM is associated with a high rate of acute complications and long-term morbidity. Aim of our study was to determine the incidence, etiological profile and complications of acute bacterial meningitis amongst children belonging to one month to five years of age.Methods: The present study was conducted over a period of one year and diagnosis of meningitis was made on basis of history, examination and laboratory investigations. Clinical features were recorded on case sheet. Lumbar puncture was done, and CSF was sent for biochemical analysis, cell counts, staining, culture and latex agglutination test (LAT).Results: Out of total 1560 admitted cases (1 month to 5years age group), 160 cases were suspected with meningitis while 57 cases were confirmed to have ABM. Most (59.6%) cases belonged to 3 months to 1-year age group and males outnumbered the females by a ratio of 2:1. Group B Streptococcus (45.6%) was most common pathogen in 45.6% cases followed by Streptococcus pneumoniae (21%) and Hemophilus influenzae (10.52%). Seizures (45%) and increased ICP (28%) were main acute complications observed during hospitalization while hemiparesis 9.6%, monoparesis 4.8%, seizures 38%, vision and hearing deficits were the sequelae observed on follow up examination. These complications were predominantly contributed by S. pneumoniae and H. Influenzae.Conclusions: The incidence of ABM is still high and Group B streptococcus is main pathogen even in post neonatal period. The complications of ABM are markedly higher in cases of S. pneumoniae, H. Influenzae meningitis in comparison to Group B streptococcus meningitis. Formulating standard protocols for management of ABM and rational antibiotic use to prevent resistance is the need of hour.
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Matheron, M. E., and M. Porchas. "Suppression of Phytophthora Root and Crown Rot on Pepper Plants Treated with Acibenzolar-S-Methyl." Plant Disease 86, no. 3 (2002): 292–97. http://dx.doi.org/10.1094/pdis.2002.86.3.292.
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The fungicide mefenoxam is registered for the control of Phytophthora blight of peppers caused by Phytophthora capsici. Isolates of the pathogen that are insensitive to mefenoxam, however, have been detected in some locations. Consequently, alternative methods are needed to control Phytophthora blight of peppers. Acibenzolar-S-methyl (ABM, Actigard) is a chemical activator of plant disease resistance that has potential for the management of Phytophthora blight of peppers. The effect of foliar applications of ABM on the development of root and crown rot on pepper plants grown in the greenhouse and inoculated with Phytophthora capsici or in soil naturally infested with the pathogen was evaluated. Inhibition of stem canker development on pepper cvs. Bell Tower and AZ9 after four treatments with ABM (75 μg/ml) was significantly greater than on plants receiving a single application of the chemical. Stem canker length on Bell Tower or AZ9 peppers was inhibited by 93.2 to 97.2% and 87.4 to 92.4% when plants were inoculated with P. capsici at 1 or 5 weeks, respectively, after the fourth application of ABM. Survival of chile pepper plants grown in field soil naturally infested with P. capsici was significantly increased by three foliar applications of ABM (75 μg/ml) compared with nontreated plants in all three trials when pots were watered daily and in two of three trials when pots were flooded for 48 h every 2 weeks. When soil was flooded every 2 weeks to establish conditions highly favorable for disease development, plants treated once with mefenoxam (100 μg/ml) survived significantly longer than those treated with ABM. On the other hand, when water was provided daily without periodic flooding to establish conditions less favorable for disease development, plant survival between the two chemicals was not different in two of three trials. Length of survival among chile pepper plants treated twice with 25, 50, or 75 μg/ml of ABM and grown in soil infested with P. capsici was not different. This work indicates that ABM could be an important management tool for Phytophthora root and crown rot on pepper plants.
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Cruz, Helena, Miguel Pinheiro, and Vítor Borges. "ReporType: A Flexible Bioinformatics Tool for Targeted Loci Screening and Typing of Infectious Agents." International Journal of Molecular Sciences 25, no. 6 (2024): 3172. http://dx.doi.org/10.3390/ijms25063172.
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In response to the pressing need for continuous monitoring of emergence and circulation of pathogens through genomics, it is imperative to keep developing bioinformatics tools that can help in their rapid characterization and classification. Here, we introduce ReporType, a versatile bioinformatics pipeline designed for targeted loci screening and typing of infectious agents. Developed using the snakemake workflow manager, ReporType integrates multiple software for read quality control and de novo assembly, and then applies ABRicate for locus screening, culminating in the production of easily interpretable reports for the identification of pathogen genotypes and/or screening of specific genomic loci. The pipeline accommodates a range of input formats, from Illumina or Oxford Nanopore Technology (ONT) reads (FASTQ) to Sanger sequencing files (AB1), or FASTA files, making it flexible for application in multiple pathogens and with different purposes. ReporType is released with pre-prepared databases for some viruses and bacteria, yet it remains easily configurable to handle custom databases. ReporType performance and functionality were validated through proof-of-concept exercises, encompassing diverse pathogenic species, including viruses such as measles, Newcastle disease virus (NDV), Dengue virus (DENV), influenza, hepatitis C virus (HCV) and Human T-Cell Lymphotropic virus type 1 (HTLV-1), as well as bacteria like Chlamydia trachomatis and Legionella pneumophila. In summary, ReporType emerges as a simple, dynamic and pan-pathogen tool, poised to evolve in tandem with the ever-changing needs of the fields of pathogen genomics, infectious disease epidemiology, and one health bioinformatics. ReporType is freely available at GitHub.
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Prasad, Rajendra, Atanu Banerjee, Nitesh Kumar Khandelwal, and Sanjiveeni Dhamgaye. "The ABCs of Candida albicans Multidrug Transporter Cdr1." Eukaryotic Cell 14, no. 12 (2015): 1154–64. http://dx.doi.org/10.1128/ec.00137-15.
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ABSTRACTIn the light of multidrug resistance (MDR) among pathogenic microbes and cancer cells, membrane transporters have gained profound clinical significance. Chemotherapeutic failure, by far, has been attributed mainly to the robust and diverse array of these proteins, which are omnipresent in every stratum of the living world.Candida albicans, one of the major fungal pathogens affecting immunocompromised patients, also develops MDR during the course of chemotherapy. The pivotal membrane transporters thatC. albicanshas exploited as one of the strategies to develop MDR belongs to either the ATP binding cassette (ABC) or the major facilitator superfamily (MFS) class of proteins. The ABC transporterCandidadrug resistance 1 protein (Cdr1p) is a major player among these transporters that enables the pathogen to outplay the battery of antifungals encountered by it. The promiscuous Cdr1 protein fulfills the quintessential need of a model to study molecular mechanisms of multidrug transporter regulation and structure-function analyses of asymmetric ABC transporters. In this review, we cover the highlights of two decades of research on Cdr1p that has provided a platform to study its structure-function relationships and regulatory circuitry for a better understanding of MDR not only in yeast but also in other organisms.
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DiLeo, Matthew V., Matthew F. Pye, Tatiana V. Roubtsova, et al. "Abscisic Acid in Salt Stress Predisposition to Phytophthora Root and Crown Rot in Tomato and Chrysanthemum." Phytopathology® 100, no. 9 (2010): 871–79. http://dx.doi.org/10.1094/phyto-100-9-0871.
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Plants respond to changes in the environment with complex signaling networks, often under control of phytohormones that generate positive and negative crosstalk among downstream effectors of the response. Accordingly, brief dehydration stresses such as salinity and water deficit, which induce a rapid and transient systemic increase in levels of abscisic acid (ABA), can influence disease response pathways. ABA has been associated with susceptibility of plants to bacteria, fungi, and oomycetes but relatively little attention has been directed at its role in abiotic stress predisposition to root pathogens. This study examines the impact of brief salinity stress on infection of tomato and chrysanthemum roots by Phytophthora spp. Roots of plants in hydroponic culture exposed to a brief episode of salt (sodium chloride) stress prior to or after inoculation were severely diseased relative to nonstressed plants. Tomato roots remained in a predisposed state up to 24 h following removal from the stress. An increase in root ABA levels in tomato preceded or temporally paralleled the onset of stress-induced susceptibility, with levels declining in roots prior to recovery from the predisposed state. Exogenous ABA could substitute for salt stress and significantly enhanced pathogen colonization and disease development. ABA-deficient tomato mutants lacked the predisposition response, which could be restored by complementation of the mutant with exogenous ABA. In contrast, ethylene, which exacerbates disease symptoms in some host–parasite interactions, did not appear to contribute to the predisposition response. Thus, several lines of evidence support ABA as a critical and dominant factor in the salinity-induced predisposition to Phytophthora spp. infection.
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García-Andrade, Javier, Beatriz González, Miguel Gonzalez-Guzman, Pedro L. Rodriguez, and Pablo Vera. "The Role of ABA in Plant Immunity is Mediated through the PYR1 Receptor." International Journal of Molecular Sciences 21, no. 16 (2020): 5852. http://dx.doi.org/10.3390/ijms21165852.
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ABA is involved in plant responses to a broad range of pathogens and exhibits complex antagonistic and synergistic relationships with salicylic acid (SA) and ethylene (ET) signaling pathways, respectively. However, the specific receptor of ABA that triggers the positive and negative responses of ABA during immune responses remains unknown. Through a reverse genetic analysis, we identified that PYR1, a member of the family of PYR/PYL/RCAR ABA receptors, is transcriptionally upregulated and specifically perceives ABA during biotic stress, initiating downstream signaling mediated by ABA-activated SnRK2 protein kinases. This exerts a damping effect on SA-mediated signaling, required for resistance to biotrophic pathogens, and simultaneously a positive control over the resistance to necrotrophic pathogens controlled by ET. We demonstrated that PYR1-mediated signaling exerted control on a priori established hormonal cross-talk between SA and ET, thereby redirecting defense outputs. Defects in ABA/PYR1 signaling activated SA biosynthesis and sensitized plants for immune priming by poising SA-responsive genes for enhanced expression. As a trade-off effect, pyr1-mediated activation of the SA pathway blunted ET perception, which is pivotal for the activation of resistance towards fungal necrotrophs. The specific perception of ABA by PYR1 represented a regulatory node, modulating different outcomes in disease resistance.
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da Costa, Kelli Monteiro, Raphael do Carmo Valente, Leonardo Marques da Fonseca, Leonardo Freire-de-Lima, Jose Osvaldo Previato, and Lucia Mendonça-Previato. "The History of the ABC Proteins in Human Trypanosomiasis Pathogens." Pathogens 11, no. 9 (2022): 988. http://dx.doi.org/10.3390/pathogens11090988.
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Human trypanosomiasis affects nearly eight million people worldwide, causing great economic and social impact, mainly in endemic areas. T. cruzi and T. brucei are protozoan parasites that present efficient mechanisms of immune system evasion, leading to disease chronification. Currently, there is no vaccine, and chemotherapy is effective only in the absence of severe clinical manifestations. Nevertheless, resistant phenotypes to chemotherapy have been described in protozoan parasites, associated with cross-resistance to other chemically unrelated drugs. Multidrug resistance is multifactorial, involving: (i) drug entry, (ii) activation, (iii) metabolism and (iv) efflux pathways. In this context, ABC transporters, initially discovered in resistant tumor cells, have drawn attention in protozoan parasites, owing to their ability to decrease drug accumulation, thus mitigating their toxic effects. The discovery of these transporters in the Trypanosomatidae family started in the 1990s; however, few members were described and functionally characterized. This review contains a brief history of the main ABC transporters involved in resistance that propelled their investigation in Trypanosoma species, the main efflux modulators, as well as ABC genes described in T. cruzi and T. brucei according to the nomenclature HUGO. We hope to convey the importance that ABC transporters play in parasite physiology and chemotherapy resistance.
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Xu, Liang, Wei Zhang, Mingjia Tang, et al. "Genome-Wide Characterization and Expression Profiling of NBS-LRR-Encoding Gene Family in Radish (Raphanus sativus L.)." Horticulturae 8, no. 12 (2022): 1164. http://dx.doi.org/10.3390/horticulturae8121164.
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Radish (Raphanus sativus L.) is an important root vegetable crop that is easily infected by various pathogens that result in decreased yield and quality. Nucleotide-binding site and leucine-rich repeat (NBS-LRR) genes play vital roles in resisting pathogen infection in plants. However, the genome-wide characterization and functional roles of NBS-LRR genes remain largely unexplored in radish. Here, a total of 187 RsNBS-LRR genes were identified at the whole-genome level in radish, among which 80 RsNBS-LRR genes were unevenly distributed on nine radish chromosomes. Interestingly, 15 clusters containing 36 RsNBS-LRR genes occurred in eight chromosomes. RNA-Seq data showed that several RsNBS-LRR genes exhibited significant differential expression profiles in different radish tissues. Moreover, a range of cis-acting regulatory elements associated with ABA, MeJA, or SA were identified in the promoter region of some RsNBS-LRR genes. RT-qPCR analysis showed that the expression of a few RsNBS-LRR genes (e.g., RsNBS021 and RsNBS163) was significantly induced under Peronospora parasitica infection and/or ABA treatment, indicating that they might play critical roles in ABA-dependent defense resistance processes. These results could enhance our understanding of the evolutionary relationship of RsNBS-LRR genes and facilitate the genetic manipulation of disease resistance in radish breeding programs.
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Nira, Sayma T., Md Farhad Hossain, Nur Uddin Mahmud, Oliul Hassan, Md Tofazzal Islam, and Abdul M. Akanda. "Alternaria leaf spot of broccoli caused by Alternaria alternata in Bangladesh." Plant Protection Science 58, No. 1 (2021): 49–56. http://dx.doi.org/10.17221/44/2020-pps.
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This study aimed to isolate and characterise the pathogen associated with Alternaria leaf spot on broccoli and to evaluate the inhibitory effects of fungicides against it. We isolated and identified the fungal pathogen as Alternaria sp. using morphological and cultural methods. Based on the aligned sequences of the internal transcribed spacer (ITS) and molecular phylogenetic analysis by the neighbour-joining method, the isolates (Ab1 and Ab2) were confirmed as Alternaria alternata. The conidia of the isolates were dark brown, cylindrical, obclavate to muriform. The conidiophores were olivaceous brown, septate, and branched. The conidial morphology of the isolates ranged from 52.4–92.4 × 10–20 μm with 2–6 transverse and 0–3 longitudinal septa. Both isolates yielded positive results in the pathogenicity test on broccoli leaves by developing brown and circular spots with concentric rings on the leaves surrounded by yellow halos. The culture studies revealed that the maximum growth of the pathogen was obtained at 30 °C and pH 6.0. Tilt 250 WC showed the highest potential in suppressing the mycelial growth of the A. alternata in vitro at a concentration as low as 50 µg/mL. The results from this study contributed to the positive identification of the pathogen and characterised A. alternata as a destructive pathogen of broccoli which may be successfully controlled by the fungicide Tilt.
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K.S, Sushma, Jayashankar M., Mohammed Ali Saeed, and Vinu A.K. "Antibacterial activity of endophytic fungi from some medicinal plants of Biligirirangana hill, India." Journal of Applied and Natural Science 10, no. 4 (2018): 1286–90. http://dx.doi.org/10.31018/jans.v10i4.1923.
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Twenty fungal endophytes were isolated from different medicinal plants of Biligirirangana Hill, Chamarajanagar dist. Phytochemical analysis of ethyl acetate extract showed positive results for tanins, flavonoids, steroids, terpenoids, glycosides, saponins and alkaloids except saponin and flavonoid tests. The crude extracts of the fungal endophytes were tested against two gram positive and two gramnegetive bacteria for its antibacterial activity. The highest zone of inhibition was produced by Fusarium sps (AB9)35mm. All the crude extracts were found to be effective against Escherichia coli, Bacillus subtilis and Staphylococcus aureus rather in Pseudomonas aerogenosa. Among them the highest inhibition zone was produced in Penicillium sp (AB11) 24mm, Cladosporium sp(AB3) 21mm, and Aspergillus sp(AB12) 30mm. Therefore, endophytic fungi can be a good source to inhibit the growth of harmful pathogens.
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Stein, Richard A. "Human Activities & the Emergence of Pathogens." American Biology Teacher 72, no. 8 (2010): 475–76. http://dx.doi.org/10.1525/abt.2010.72.8.2.
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