Dear Editor,The highly pathogenic avian influenza viruses(HPAIVs)are important epizootic and zoonotic pathogens that cause significant economic losses to the poultry industry and pose a serious risk to veterinary and ...Dear Editor,The highly pathogenic avian influenza viruses(HPAIVs)are important epizootic and zoonotic pathogens that cause significant economic losses to the poultry industry and pose a serious risk to veterinary and public health.Wild birds have been recognized as the primary reservoirs for influenza A virus,and some species show little sign of clinical disease or even can be asymptomatic during long distance carriers of the virus(Lycett et al.,2019).Since it was first discovered in 1959,the H5Nx HPAIVs have spread globally and cause outbreaks in wild birds,poultry and sporadic human and other mammalian infections(Lycett et al.,2019).Due to the reassortant events of diverse strains facilitated by migratory waterfowl,the clade 2.3.4.4 of H5Nx viruses acquiring neuraminidase(NA)gene from other low pathogenicity avian influenza viruses(LPAIVs)emerged in 2014 and gradually became the dominant sub-clade(Lee et al.,2017).展开更多
The Salmonella pathogenicity islands(SPIs) play crucial roles in the progression of Salmonella infection. In this study, we constructed an improved λ Red homologous recombination system to prepare single and triple d...The Salmonella pathogenicity islands(SPIs) play crucial roles in the progression of Salmonella infection. In this study, we constructed an improved λ Red homologous recombination system to prepare single and triple deletion mutants of 3 prominent SPIs(SPI-1, 2, and 3), aiming at the impact of deletion on morphology, carbon source metabolism, adhesion and invasion capacity, in vivo colonization, and immune efficacy in chicks. Our examination revealed that the surface of the single deletion mutants(SM6ΔSPI1, ΔSPI2, and ΔSPI3) exhibited a more rugged texture and appeared to be enveloped in a layer of transparent colloid, whereas the morphology of the triple deletion mutant(SM6ΔSPI1&2&3) remained unaltered when compared to the parent strain. The carbon metabolic spectrum of the SPI mutants underwent profound alterations, with a notable and statistically significant modification observed in 30 out of 95 carbon sources, primarily carbohydrates(17 out of 30). Furthermore, the adhesion capacity of the 4 mutants to Caco-2 cells was significantly reduced when compared to that of the parent strain. Moreover,the invasion capacity of mutants SM6ΔSPI1 and SM6ΔSPI1&2&3 exhibited a substantial decrease, while it was enhanced to varying degrees for SM6ΔSPI3 and SM6ΔSPI2. Importantly, none of the 4 mutants induced any clinical symptoms in the chicks. However, they did transiently colonize the spleen and liver. Notably, the SM6ΔSPI1&2&3mutant was rapidly cleared from both the spleen and liver within 8 days post-infection and no notable pathological changes were observed in the organs. Additionally, when challenged, the mutants immunized groups displayed a significant increase in antibody levels and alterations in the CD3+CD4+ and CD3+CD8+ subpopulations, and the levels of IL-4 and IFN-γ cytokines in the SM6ΔSPI1&2&3 immunized chicken serum surpassed those of other groups.In summary, the successful construction of the 4 SPI mutants lays the groundwork for further exploration into the pathogenic(including metabolic) mechanisms of SPIs and the development of safe and effective live attenuated Salmonella vaccines or carriers.展开更多
Hypertrophic cardiomyopathy(HCM)is an autosomal dominant inherited cardiomyopathy characterized by left ventricular hypertrophy.It is one of the chief causes of sudden cardiac death in younger people and athletes.Mole...Hypertrophic cardiomyopathy(HCM)is an autosomal dominant inherited cardiomyopathy characterized by left ventricular hypertrophy.It is one of the chief causes of sudden cardiac death in younger people and athletes.Molecular-genetic studies have confirmed that the vast majority of HCM is caused by mutations in genes encoding sarcomere proteins.HCM has a relatively wide phenotypic heterogeneity,varying from asymptomatic to sudden cardiac death,because of the many different mutations and pathogenic genes underlying it.Many studies have explored the clinical symptoms and prognosis of HCM,emphasizing the importance of genotype in evaluating patient prognosis and guiding the clinical management of HCM.To elaborate the main pathogenic genes and phenotypic prognosis in HCM to promote a better understanding of this genetic disease.Retrospective analysis of literature to evaluate the association between underlying gene mutations and clinical phenotypes in HCM patients.As sequencing technology advances,the pathogenic gene mutation spectrum and phenotypic characteristics of HCM are gradually becoming clearer.HCM is a widespread inherited disease with a highly variable clinical phenotype.The precise mechanisms linking known pathogenic gene mutations and the clinical course of this heterogeneous condition remain elusive.展开更多
Coffee wilt represents one of the most devastating diseases of Arabica coffee(Coffea arabica L.)plantations in the primary coffee-producing regions.In this study,coffee trees manifesting wilt symptoms accompanied by t...Coffee wilt represents one of the most devastating diseases of Arabica coffee(Coffea arabica L.)plantations in the primary coffee-producing regions.In this study,coffee trees manifesting wilt symptoms accompanied by the defoliation and drying of the whole tree were observed in the Jazan,El Baha,Najran,and Asir regions.The purpose of this investigation was to isolate and identify the Fusarium species recovered from symptomatic coffee trees.The developed fungi were initially characterized based on their morphological features followed by molecular phylogenetic multi-locus analysis of the combined sequences of ITS,TEF1-α,RPB2,and CaM.Twenty-five isolates were recovered from 28 samples.All fungal isolates were categorized morphologically under the genus Fusarium.Phylogenetic analysis positioned all the representative 15 isolates into one cluster grouping together with Neocosmospora falciformis(formerly F.falciforme)confirming their taxonomic position.Pathogenicity tests of the N.falciformis isolates were subsequently conducted on coffee seedlings,and the results revealed that all isolates induced wilt symptoms resembling those recorded in the field,and the incidence was 100%.The fungicide sensitivity test of seven investigated fungicides revealed that Maxim XL^(®) followed by Moncut^(®) exhibited the highest inhibitory effect against N.falciformis KSA 24-14,reaching 93.33%and 91.67%,respectively.To our knowledge,N.falciformis is a new causal pathogen of coffee wilt in Saudi Arabia.Remarkably,these results offer important insights for devising effective approaches to monitor and control such diseases.展开更多
Grape white rot caused by Coniella vitis is a global concern in the grape industry.pH regulation is essential for cell growth,reproductive processes and pathogenicity in phytopathogenic fungi.In this study,we observed...Grape white rot caused by Coniella vitis is a global concern in the grape industry.pH regulation is essential for cell growth,reproductive processes and pathogenicity in phytopathogenic fungi.In this study,we observed that the growth rate,spore production and virulence of C.vitis significantly declined in alkaline pH,as well as the suppressive effect on secretion of hydrolytic enzymes.Transcriptomic and metabolomic analyses were used to investigate the responses of C.vitis to acidic(pH 5),neutral(pH 7)and alkaline environments(pH 9).We identified 728,1,780 and 3,386 differentially expressed genes(DEGs)at pH 5,pH 7 and pH 9,when compared with the host pH(pH 3),and 2,122 differently expressed metabolites(DEMs)in negative and positive ion mode.Most DEGs were involved in carbohydrate metabolic process,transmembrane transport,tricarboxylic acid cycle,peptide metabolic process,amide biosynthetic process,and organic acid metabolic process.In addition,metabolomic analysis revealed ABC transporters,indole alkaloid biosynthesis,diterpenoid biosynthesis,and carotenoid biosynthesis pathways in response to the pH change.Furthermore,we found that the aspartate synthesis metabolic route associated with the TCA cycle is a key limiting factor for the growth and development of C.vitis in alkaline environments,and aspartate supplementation enables C.vitis to grow in alkaline environments.Plant cell wall-degrading enzymes(PCWDEs)could contribute to the pathogenicity,when C.vitis infected at pH 3.Importantly,aflatrem biosynthesis in acidic environment might contribute to the virulence of C.vitis and has a risk of causing human health problems due to its acute neurotoxic effects.展开更多
Magnaporthe oryzae is the causal agent of rice blast. Glycosylation plays key roles in vegetative growth,development, and infection of M. oryzae. However, several glycosylation-related genes have not been characterize...Magnaporthe oryzae is the causal agent of rice blast. Glycosylation plays key roles in vegetative growth,development, and infection of M. oryzae. However, several glycosylation-related genes have not been characterized.In this study, we identified a Glyco_transf_22 domain-containing protein, MoAlg9, and found that MoAlg9 islocalized to the endoplasmic reticulum(ER). Deletion of MoALG9 significantly affected conidial production, normalappressorium formation, responses to stressors, and pathogenicity of M. oryzae. We also found that the ΔMoalg9mutant was defective in glycogen utilization, appressorial penetration, and invasive growth in host cells. Moreover,we further demonstrated that MoALG9 regulates the transcription of several target genes involved in conidiation,appressorium formation, and cell wall integrity. In addition, we found that the Glyco_transf_22 domain is essentialfor normal MoAlg9 function and localization. We also provide evidence that MoAlg9 is involved in N-glycosylationpathway in M. oryzae. Taken together, these results show that MoAlg9 is important for conidiation, appressoriumformation, maintenance of cell wall integrity, and the pathogenesis of M. oryzae.展开更多
Plant pathogens secrete various cell wall-degrading enzymes that compromise host cell wall integrity and facilitate pathogen invasion.This study identified VdGH7a,a glycoside hydrolase family 7(GH7)cellobiohydrolase f...Plant pathogens secrete various cell wall-degrading enzymes that compromise host cell wall integrity and facilitate pathogen invasion.This study identified VdGH7a,a glycoside hydrolase family 7(GH7)cellobiohydrolase from Verticillium dahliae,which demonstrated hydrolytic activity against 1,4-β-glucan.Notably,VdGH7a induced cell death in Nicotiana benthamiana when signal peptides were present,though this effect was inhibited by the carbohydrate-binding type-1(CBM1)protein domain.The deletion of VdGH7a substantially reduced V.dahliae pathogenicity in cotton plants,as demonstrated by the mutants’inability to penetrate cellophane membrane.These knockout mutants also exhibited reduced carbon source utilization capacity and increased sensitivity to osmotic and cell wall stresses.Through yeast two-hybrid screening,bi-molecular fluorescence complementation(BiFC),and luciferase complementation imaging(LCI),we identified that VdGH7a interacts with an osmotin-like protein(GhOLP1)in cotton.Virus-induced gene silencing of GhOLP1 resulted in decreased salicylic acid(SA)content and reduced resistance to V.dahliae in cotton,while heterologous overexpression of GhOLP1 in Arabidopsis enhanced both resistance and SA signaling pathway gene expression.These results reveal a virulence mechanism wherein the secreted protein VdGH7a from V.dahliae interacts with GhOLP1 to activate host immunity and contribute significantly to plant resistance against V.dahliae.展开更多
Background:New variants of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)continue to drive global epidemics and pose significant health risks.The pathogenicity of these variants evolves under immune press...Background:New variants of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)continue to drive global epidemics and pose significant health risks.The pathogenicity of these variants evolves under immune pressure and host factors.Understanding these changes is crucial for epidemic control and variant research.Methods:Human angiotensin-converting enzyme 2(hACE2)transgenic mice were in-tranasally challenged with the original strain WH-09 and the variants Delta,Beta,and Omicron BA.1,while BALB/c mice were challenged with Omicron subvariants BA.5,BF.7,and XBB.1.To compare the pathogenicity differences among variants,we con-ducted a comprehensive analysis that included clinical symptom observation,meas-urement of viral loads in the trachea and lungs,evaluation of pulmonary pathology,analysis of immune cell infiltration,and quantification of cytokine levels.Results:In hACE2 mice,the Beta variant caused significant weight loss,severe lung inflammation,increased inflammatory and chemotactic factor secretion,greater mac-rophage and neutrophil infiltration in the lungs,and higher viral loads with prolonged shedding duration.In contrast,BA.1 showed a significant reduction in pathogenicity.The BA.5,BF.7,and XBB.1 variants were less pathogenic than the WH-09,Beta,and Delta variants when infected in BALB/c mice.This was evidenced by reduced weight loss,diminished pulmonary pathology,decreased secretion of inflammatory factors and chemokines,reduced macrophage and neutrophil infiltration,as well as lower viral loads in both the trachea and lungs.Conclusion:In hACE2 mice,the Omicron variant demonstrated the lowest pathogenic-ity,while the Beta variant exhibited the highest.Pathogenicity of the Delta variant was comparable to the original WH-09 strain.Among BALB/c mice,Omicron subvari-ants BA.5,BF.7,and XBB.1 showed no statistically significant differences in virulence.展开更多
In Candida species,the endoplasmic reticulum(ER)stress response—regulated by the unfolded protein response(UPR)—serves as a critical adaptive mechanism affecting both pathogenicity and antifungal resistance.This rev...In Candida species,the endoplasmic reticulum(ER)stress response—regulated by the unfolded protein response(UPR)—serves as a critical adaptive mechanism affecting both pathogenicity and antifungal resistance.This review aims to synthesize current knowledge on ER stress pathways in Candida glabrata and Candida albicans,highlighting their species-specific adaptations and therapeutic implications.We systematically analyzed peer-reviewed literature on ER stress mechanisms in Candida,focusing on comparative studies of UPR signaling.Emphasis was placed on C.glabrata’s inositol-requiring enzyme 1(IRE1)-dependent Regulated IRE1-Dependent Decay(RIDD)pathway and C.albicans’IRE1/HAC1 and calcium-mediated pathways.Connections to virulence and drug resistance were evaluated through genetic,transcriptomic,and phenotypic evidence.Candida species employ divergent UPR strategies:C.glabrata mitigates ER stress primarily via RIDD-mediated mRNA decay to reduce protein load,while C.albicans enhances folding capacity through HAC1 splicing and calcium homeostasis.These adaptations promote survival in hostile host environments(e.g.,oxidative stress,immune attacks)and are linked to resistance against azoles and echinocandins.Pharmacological disruption of UPR components(e.g.,IRE1 inhibitors)sensitizes Candida to antifungals in experimental models.ER stress response pathways are promising targets for antifungal drug development.Understanding species-specific UPR mechanisms in Candida could guide novel therapies to overcome resistance and improve treatment outcomes.展开更多
The H4 subtype of avian influenza virus(AIV)is prevalent worldwide,but only receives little attention due to its low pathogenicity in poultry.Consequently,it remains largely unclear whether H4 AIVs pose a potential th...The H4 subtype of avian influenza virus(AIV)is prevalent worldwide,but only receives little attention due to its low pathogenicity in poultry.Consequently,it remains largely unclear whether H4 AIVs pose a potential threat to the poultry industry and public health.During the period from 2011 to 2022,we conducted an active surveillance programm.A total of 154,762 swab samples were collected across various provinces,and 427 H4 viruses were detected,resulting in a positivity rate of 0.28%.All H4 viruses were isolated from poultry,primarily from ducks in live poultry markets.We further investigated the genetic evolutionary characteristics and pathogenicity of 20 H4Nx viruses isolated in our program.Phylogenetic analysis revealed that the 20 H4Nx viruses belonged to the Eurasian lineage and exhibited significant genetic diversity,with 19 distinct genotypes identified.Molecular characterization indicated that these viruses were low-pathogenicity AIVs with limited binding affinity to human receptors,yet they contained mutations associated with enhanced viral replication and pathogenicity in mammals.Pathogenicity tests conducted in ducks demonstrated that H4 viruses were weakly pathogenic,exhibiting limited replication and transmission capabilities.However,some viruses were able to replicate effectively in mice and induce weight loss.For instance,DK/AH/AG61/11(H4N6)can replicate efficiently in MDCK cells,indicating a potential threat to mammals.These findings underscore the importance of ongoing surveillance of H4 AIVs to better understand their evolution and transmission dynamics and to prevent potential public health risks.展开更多
[Objective] The study was to isolate and identify the pathogen of Pandora neoaphidis and to determine its pathogenicity against turnip aphid （Lipaphis erysimi）.[Method] Based on the morphological characteristics,the...[Objective] The study was to isolate and identify the pathogen of Pandora neoaphidis and to determine its pathogenicity against turnip aphid （Lipaphis erysimi）.[Method] Based on the morphological characteristics,the species of pathogenic fungus was identified.Spore shower method was used to carry out bioassay on the pathogen against turnip aphid.[Result] Primary conidia were ovoid,bitunicate and uninucleate,（24.7±1.4）μm×（10.7±0.9）μm,L/D=2.3±0.2.Secondary conidia had the similar shape with the primary ones,（18.6±2.1）μm×（13.3±1.3）μm,L/D=1.4±0.2.Hyphal body was like mycelium with the diameter of （10.6±0.8）μm.Conidiophores had palmate branch with the diameter of （10.0±0.9）μm.Pseudocystidia was not branched,which had rough base with the diameter of （19.2±1.7）μm,and gradually became more angular towards the apex with the diameter of （8.0±0.9）μm at tips.Rhizoid was like monohyphal shape with the diameter of （21.0±3.0）μm at base,the terminal apex had regular discoid holdfast.No resting spores were observed.The lethal dose of the pathogen against turnip aphid was 18.2/mm2.[Conclusion] The entomopathogenic fungus against turnip aphid was identified to be Pandora neoaphidis,and the pathogen was confirmed to have strong pathogenicity against turnip aphid.展开更多
[Objective] The pathogenic Escherichia coli in musk deer was classified at molecular level to provide basic materials for molecular epidemiology of pathogenic Escherichia coli in musk deer. [Method] Plasmids from 24 p...[Objective] The pathogenic Escherichia coli in musk deer was classified at molecular level to provide basic materials for molecular epidemiology of pathogenic Escherichia coli in musk deer. [Method] Plasmids from 24 pathogenic Escherichia coli in musk deer were extracted by the Lysis Triton method, and then identified by single enzyme digestion with three endonucleases of Hind Ⅲ, EcoR Ⅰ and BamH Ⅰ. [Result] The yield rate of plasmids was 91.6%, and 24 pathogenic Escherichia coli in musk deer had the identical or similar plasmid profiles. [Conclusion] Plasmid DNA analysis offers scientific basis for molecular epidemiology of pathogenic Escherichia coli in musk deer in Sichuan Institute of Musk Deer Breeding.展开更多
[Objective] This study aimed to investigate the genetic variation of g E gene of an epidemic pseudorabies virus（PRV） strain and its pathogenicity to piglets. [Method] By serial passage in Vero cells, a PRV strain wa...[Objective] This study aimed to investigate the genetic variation of g E gene of an epidemic pseudorabies virus（PRV） strain and its pathogenicity to piglets. [Method] By serial passage in Vero cells, a PRV strain was isolated from the brain tissues of stillborn fetuses delivered by sows with suspected PRV infection and preliminarily identified by PCR. g E gene of the isolated PRV strain was amplified and sequenced for phylogenetic analysis. In addition, the pathogenicity of the isolated PRV strain to 6-week-old piglets was evaluated. [Result] A PRV strain was successfully isolated and named PRV N5 B strain, which could proliferate in Vero cells and TCID50 of the 15 thgeneration virus liquid reached 10^7.125/0.1 ml. Specific bands could be amplified by PCR. g E gene in the isolated PRV strain was 1 740 bp in length. A phylogenetic tree was constructed based on full-length g E sequences, which showed that PRV N5 B strain and PRV strains isolated since 2012 were clustered into the same independent category and shared 99.7%-100% homology of nucleotide sequences. Compared with related sequences published previously, there were insertions of three consecutive bases at two loci. Animal experiments showed that intranasal inoculation of 6-week-old piglets with 2 ml of PRV N5 B strain（10^6/0.1 ml） led to a mortality rate of 100%. [Conclusion] In this study,genetic variability of g E gene in PRV N5 B isolate and its pathogenicity to piglets were analyzed, which provided a theoretical basis for the development of new vaccines to prevent and control porcine pseudorabies.展开更多
[Objective] The biological characteristics and pathogenicities of Shewanella algae and Shewanella abalone from Babylonia were studied in this paper. [Method]The hemolytic bacteria were isolated from the hepatopancreas...[Objective] The biological characteristics and pathogenicities of Shewanella algae and Shewanella abalone from Babylonia were studied in this paper. [Method]The hemolytic bacteria were isolated from the hepatopancreas of Babylonia suffered from proboscis edema with blood agar plate. The dominant bacterial community in the ill Babylonia was identified by 16 S r DNA sequence analysis, and the bacterial cultural and biochemical characteristics and pathogenicities were studied. [Result]The Shewanella bacteria, including Shewanella algae and Shewanella abalone, are the dominant bacterial community in Babylonia suffered from proboscis edema.The colony characteristics of Shewanella algae in nutrient agar medium, TCBS agar medium and CHROMagar vibrio colored medium were similar to those of Shewanella abalone. Shewanella algae possessed β-hemolysis and Shewanella abalone possessed α-hemolysis in the blood agar plate. The biochemical reaction of Shewanella algae and Shewanella abalone was all of non-fermentation type. The results of artificial infection test showed that half lethal dose（LD50） of the test strains of Shewanella algae was 10-5.50/0.1 ml. The test strains of Shewanella algae have strong toxicity, and could cause mice and chickens to die of sepsis with mortality of100%. The mortality of Babylonia infected with Shewanella algae was 10%; while the survived Babylonia lost the ability of moving and intaking for a long time, but they were not suffered from proboscis edema. There was no death in mice or chicks infected with Shewanella abalone, but their livers and spleens were slightly hyperemic and swelling. There was also no death in Babylonia infected with Shewanella abalone, but their intaking and moving ability was lost for a short time.[Conclusion] Although Shewanella algae and Shewanella abalone were the dominant bacteria in Babylonia suffered from proboscis edema, they were not the main pathogenic bacteria for proboscis edema. Shewanella algae had strong pathogenicity to mice, chicks and Babylonia, while Shewanella abalone showed no marked pathogenicity to those experimental animals in this study.展开更多
Tobacco root-knot nematode disease has caused severe damage in Geng- ma County, Yunnan Province. In order to identify the pathogenic factors of the tobac- co root-knot nematode disease in this county, the pathogenic n...Tobacco root-knot nematode disease has caused severe damage in Geng- ma County, Yunnan Province. In order to identify the pathogenic factors of the tobac- co root-knot nematode disease in this county, the pathogenic nematodes, hosts and environment of tobacco fields in Mengsa, Hepai and Sipaishan 3 main tobacco-grow- ing towns in Gengma County were investigated and analyzed based on the local re- lated field survey on tobacco root-knot nematode disease in this county in 2012. The results showed the incidence and severity of the tobacco root-knot nematode disease were all higher than those of previous years. dominant pathogens of the tobacco root-knot The species identification showed the nematode disease were Meloidogyne arenaria and M. javanica in Gengma County. The lacking of disease-resistant culti- vars, poor management and climatic anomaly were the main causes of the tobacco root-knot nematode disease in Gengma. According to the occurrence characteristics of the disease, the agricultural prevention-based control measures were proposed.展开更多
A multivalent inactivated Escherichia coli vaccine for forest musk deer by using serotypes O4,O26,and O139 with Al（OH）3 adjuvant was prepared.The vaccine did not cause any adverse reactions in forest musk deer.The i...A multivalent inactivated Escherichia coli vaccine for forest musk deer by using serotypes O4,O26,and O139 with Al（OH）3 adjuvant was prepared.The vaccine did not cause any adverse reactions in forest musk deer.The immunogenic effects of the vaccine were experimentally investigated in pregnant and young forest musk deer.The serum antibody titers of pregnant and young forest musk deer were determined by performing the micro-agglutination test.The serum antibody titers of pregnant forest musk deer were more stable from 35th to 68th d after the third vaccination,and the serum antibody titers of four pregnant forest musk deer were maintained 25,25,25,and 24 on 68th d after the third vaccination.Young forest musk deer showed serum antibody titers which were obtained due to nursing.Young forest musk deer were administered the first intramuscular vaccine injection at an age of approximately 60 days due to a fall in maternal antibody titers.The serum antibody titers of young forest musk deer were higher after the third vaccination and maintained at approximately the same level until they were 137 days old.The maternal antibodies and the antibodies produced by young forest musk deer could be helpful for protecting the young musk deer from the infections of pathogenic Escherichia coli strains（serotypes O4,O26,and O139）for 137 days after birth（during the nursing period and the period when the forest musk deer were susceptible to diseases）.展开更多
[Objective] This study was conducted to investigate the pathogenicity of Plasmodiophora brassicae on cabbage grown under different temperature and soil pH conditions. [Method] The pathogenicity of P. brassicae were te...[Objective] This study was conducted to investigate the pathogenicity of Plasmodiophora brassicae on cabbage grown under different temperature and soil pH conditions. [Method] The pathogenicity of P. brassicae were tested at seven different temperatures and at six different soil pH values with the resting spore concentration of lx108 （spores/g） in the soil. The plant survival rate and incidence rate of clubroot were investigated after 90 d. [Result] The incidence rate of clubroot on cabbage among the different temperature sets varied in a descending order as follows： 30 ℃〉25 ℃〉20 ℃〉35 ℃〉15 ℃〉10 ℃〉5 ℃ at soil pH value of 6, indicating that the pathogenicity of P. brassicae was weak at 5 and 10 ~（3. The incidence rate increased with soil temperature increasing from 15 to 30 ℃, but decreased at 35 ℃. The incidence rates of clubroot were 80.36%, 100%, 65%, 10.77%, 3.23% and 0% at soil pH 4, 5, 6, 7, 8 and 9 at 25 ℃, respectively. The growth of cabbage was inhibited and the survival rate was reduced at pH 4.The incidence rates of clubroot were low at pH value of 7 and 8, and was 0% at pH 9. The Chinese cabbage grew better at pH value of 5 and 6, but had high incidence rates of clubroot. [Conclusion] The results revealed that the incidence rate of clubroot on cabbage was closely related to the temperature and soil pH.展开更多
[Objective] This study was to investigate the relationship between biological characteristics of Beauveria bassiana （Bals.） Vuill and pathogenicity to Bombyx rnori L, with the aim to provide scientific basis for the...[Objective] This study was to investigate the relationship between biological characteristics of Beauveria bassiana （Bals.） Vuill and pathogenicity to Bombyx rnori L, with the aim to provide scientific basis for the control of white muscardine in Bombyx mori L. [Method] The strains isolated and purified from the 6 Beauveria bassiana biocontrol agents from all over the country and the 3 white muscardine silkworms collected from Guangxi provincial silkworm rearing areas were identified by the morphological observation and molecular biology technology. The pathogenicity of B. bassaina to silkworms was determined, and the biological characteristics such as growth diameter, sporulation and the extracellular protease activity of the different B. bassiana strains were compared. [Result] The isolated 9 strains were all B. bassaina （Bals.） Vuillemin, and all strains had high pathogenicity to silkworm, but with different pathogenicities. The growth diameter, sporulation and extracellular protease activity of different B. bassiana strains were also different, and showed correlation with the patheogenicity to silkworms. [Conclusion] B. bassiana spores production amount and exocellular protease activity had significant positive correlation with their pathogenicity to silkworm.展开更多
Verticillium wilt,caused by the notorious fungal pathogen Verticillium dahliae,is one of the main limiting factors for cotton production.Due to the stable dormant structure microsclerotia,long-term variability and co-...Verticillium wilt,caused by the notorious fungal pathogen Verticillium dahliae,is one of the main limiting factors for cotton production.Due to the stable dormant structure microsclerotia,long-term variability and co-evolution with host plant,its pathogenicity mechanism is very complicated,and the interaction mechanism between pathogen and host plant is also unclear.So identification and functional analysis of the genes involved in the pathogenicity or virulence of this fungus will benefit to uncover the molecular pathogenic mechanism of V.dahliae.In this review,many multifunction genes covering microsclerotia development,pathogen infection,effector proteins,transcription factors,horizontal gene transfer and trans-kingdom RNA silencing have been summarized to provide a theoretical basis to deep understand the molecular pathogenicity mechanism of V.dahliae and promote to effectively control Verticillium wilt.Furtherly,these pathogenicity-related genes may be considered as targets for effective control of Verticillium wilt in cotton.展开更多
Since May 2006,a highly pathogenic porcine reproductive and respiratory syndrome virus （HP-PRRSV） variant characterized by 30 amino acids deletion within its NSP2-coding region emerged and caused extensive economic ...Since May 2006,a highly pathogenic porcine reproductive and respiratory syndrome virus （HP-PRRSV） variant characterized by 30 amino acids deletion within its NSP2-coding region emerged and caused extensive economic losses to China＇s pig industry.To investigate the in vivo pathogenicity and immune responses of the newly emerging PRRSV,3 groups of 60-d-old conventional piglets were inoculated intranasally with a representative strain of the HP-PRRSV variant HuN4 with 3 different infection doses （3×103-3×105 TCID50）.The results revealed that the virus variant caused severe disease in piglets and the significant clinical characteristics consisted of persistently high fever （41.0-41.9oC） and high morbidity and mortality （60-100%）,the marked clinical signs of PRRS and severe histopathogenic damages in multiple organs.It induced rapid and intense humoral immune responses and seroconversion was detected in most infected pigs at 7 d post-infection （DPI）.The virus vigorously replicated in vivo and the highest virus average titer was 9.7 log copies mL-1 serum at 7 DPI.Elevated levels of IFN-g and IL-10 cytokine production in serum in this study were also observed.Taken together,our results demonstrated that the HP-PRRSV variant HuN4 strain is highly pathogenic for piglets and suitable to be a reference strain of highly virulent PRRSV for evaluating the efficacy of the new vaccines.展开更多
基金supported by Zhejiang Province Science and Technology Cooperation Project of“Three Rural and Nine Parties”(grant number 2023SNJF059).
文摘Dear Editor,The highly pathogenic avian influenza viruses(HPAIVs)are important epizootic and zoonotic pathogens that cause significant economic losses to the poultry industry and pose a serious risk to veterinary and public health.Wild birds have been recognized as the primary reservoirs for influenza A virus,and some species show little sign of clinical disease or even can be asymptomatic during long distance carriers of the virus(Lycett et al.,2019).Since it was first discovered in 1959,the H5Nx HPAIVs have spread globally and cause outbreaks in wild birds,poultry and sporadic human and other mammalian infections(Lycett et al.,2019).Due to the reassortant events of diverse strains facilitated by migratory waterfowl,the clade 2.3.4.4 of H5Nx viruses acquiring neuraminidase(NA)gene from other low pathogenicity avian influenza viruses(LPAIVs)emerged in 2014 and gradually became the dominant sub-clade(Lee et al.,2017).
基金supported by the National KeyR&DProgramof China(2022YFF0710500)the National Natural Science Foundation of China(32172853 and 32373013)the Central Public-interest Scientific Institution Basal Research Fund,China(1610302022001).
文摘The Salmonella pathogenicity islands(SPIs) play crucial roles in the progression of Salmonella infection. In this study, we constructed an improved λ Red homologous recombination system to prepare single and triple deletion mutants of 3 prominent SPIs(SPI-1, 2, and 3), aiming at the impact of deletion on morphology, carbon source metabolism, adhesion and invasion capacity, in vivo colonization, and immune efficacy in chicks. Our examination revealed that the surface of the single deletion mutants(SM6ΔSPI1, ΔSPI2, and ΔSPI3) exhibited a more rugged texture and appeared to be enveloped in a layer of transparent colloid, whereas the morphology of the triple deletion mutant(SM6ΔSPI1&2&3) remained unaltered when compared to the parent strain. The carbon metabolic spectrum of the SPI mutants underwent profound alterations, with a notable and statistically significant modification observed in 30 out of 95 carbon sources, primarily carbohydrates(17 out of 30). Furthermore, the adhesion capacity of the 4 mutants to Caco-2 cells was significantly reduced when compared to that of the parent strain. Moreover,the invasion capacity of mutants SM6ΔSPI1 and SM6ΔSPI1&2&3 exhibited a substantial decrease, while it was enhanced to varying degrees for SM6ΔSPI3 and SM6ΔSPI2. Importantly, none of the 4 mutants induced any clinical symptoms in the chicks. However, they did transiently colonize the spleen and liver. Notably, the SM6ΔSPI1&2&3mutant was rapidly cleared from both the spleen and liver within 8 days post-infection and no notable pathological changes were observed in the organs. Additionally, when challenged, the mutants immunized groups displayed a significant increase in antibody levels and alterations in the CD3+CD4+ and CD3+CD8+ subpopulations, and the levels of IL-4 and IFN-γ cytokines in the SM6ΔSPI1&2&3 immunized chicken serum surpassed those of other groups.In summary, the successful construction of the 4 SPI mutants lays the groundwork for further exploration into the pathogenic(including metabolic) mechanisms of SPIs and the development of safe and effective live attenuated Salmonella vaccines or carriers.
基金Supported by National Natural Science Foundation of China,No.81770379 and 81470521.
文摘Hypertrophic cardiomyopathy(HCM)is an autosomal dominant inherited cardiomyopathy characterized by left ventricular hypertrophy.It is one of the chief causes of sudden cardiac death in younger people and athletes.Molecular-genetic studies have confirmed that the vast majority of HCM is caused by mutations in genes encoding sarcomere proteins.HCM has a relatively wide phenotypic heterogeneity,varying from asymptomatic to sudden cardiac death,because of the many different mutations and pathogenic genes underlying it.Many studies have explored the clinical symptoms and prognosis of HCM,emphasizing the importance of genotype in evaluating patient prognosis and guiding the clinical management of HCM.To elaborate the main pathogenic genes and phenotypic prognosis in HCM to promote a better understanding of this genetic disease.Retrospective analysis of literature to evaluate the association between underlying gene mutations and clinical phenotypes in HCM patients.As sequencing technology advances,the pathogenic gene mutation spectrum and phenotypic characteristics of HCM are gradually becoming clearer.HCM is a widespread inherited disease with a highly variable clinical phenotype.The precise mechanisms linking known pathogenic gene mutations and the clinical course of this heterogeneous condition remain elusive.
基金funded by the Deanship of Scientific Research,Vice Presidency for Graduate Studies and Scientific Research,King Faisal University,Saudi Arabia,for supporting this work for work through grant number KFU242134.
文摘Coffee wilt represents one of the most devastating diseases of Arabica coffee(Coffea arabica L.)plantations in the primary coffee-producing regions.In this study,coffee trees manifesting wilt symptoms accompanied by the defoliation and drying of the whole tree were observed in the Jazan,El Baha,Najran,and Asir regions.The purpose of this investigation was to isolate and identify the Fusarium species recovered from symptomatic coffee trees.The developed fungi were initially characterized based on their morphological features followed by molecular phylogenetic multi-locus analysis of the combined sequences of ITS,TEF1-α,RPB2,and CaM.Twenty-five isolates were recovered from 28 samples.All fungal isolates were categorized morphologically under the genus Fusarium.Phylogenetic analysis positioned all the representative 15 isolates into one cluster grouping together with Neocosmospora falciformis(formerly F.falciforme)confirming their taxonomic position.Pathogenicity tests of the N.falciformis isolates were subsequently conducted on coffee seedlings,and the results revealed that all isolates induced wilt symptoms resembling those recorded in the field,and the incidence was 100%.The fungicide sensitivity test of seven investigated fungicides revealed that Maxim XL^(®) followed by Moncut^(®) exhibited the highest inhibitory effect against N.falciformis KSA 24-14,reaching 93.33%and 91.67%,respectively.To our knowledge,N.falciformis is a new causal pathogen of coffee wilt in Saudi Arabia.Remarkably,these results offer important insights for devising effective approaches to monitor and control such diseases.
基金supported by the Shandong Provincial Natural Science Foundation,China(ZR2021QC131)the Shandong Province Key Research and Development Plan,China(2022TZXD001102)+1 种基金the Shandong Province Demonstration Project for Model Construction in Rural Revitalization Service,China(2022DXAL0226)the Innovation Project of Shandong Academy of Agricultural Sciences,China(CXGC2023F15,CXGC2023A41,and CXGC2023A47)。
文摘Grape white rot caused by Coniella vitis is a global concern in the grape industry.pH regulation is essential for cell growth,reproductive processes and pathogenicity in phytopathogenic fungi.In this study,we observed that the growth rate,spore production and virulence of C.vitis significantly declined in alkaline pH,as well as the suppressive effect on secretion of hydrolytic enzymes.Transcriptomic and metabolomic analyses were used to investigate the responses of C.vitis to acidic(pH 5),neutral(pH 7)and alkaline environments(pH 9).We identified 728,1,780 and 3,386 differentially expressed genes(DEGs)at pH 5,pH 7 and pH 9,when compared with the host pH(pH 3),and 2,122 differently expressed metabolites(DEMs)in negative and positive ion mode.Most DEGs were involved in carbohydrate metabolic process,transmembrane transport,tricarboxylic acid cycle,peptide metabolic process,amide biosynthetic process,and organic acid metabolic process.In addition,metabolomic analysis revealed ABC transporters,indole alkaloid biosynthesis,diterpenoid biosynthesis,and carotenoid biosynthesis pathways in response to the pH change.Furthermore,we found that the aspartate synthesis metabolic route associated with the TCA cycle is a key limiting factor for the growth and development of C.vitis in alkaline environments,and aspartate supplementation enables C.vitis to grow in alkaline environments.Plant cell wall-degrading enzymes(PCWDEs)could contribute to the pathogenicity,when C.vitis infected at pH 3.Importantly,aflatrem biosynthesis in acidic environment might contribute to the virulence of C.vitis and has a risk of causing human health problems due to its acute neurotoxic effects.
基金supported by the National Natural Science Foundation of China (32202253)the Natural Science Foundation of Anhui Higher Education Institutions, China (KJ2020A0102)the Talent Research Project of Anhui Agricultural University, China (rc342001)。
文摘Magnaporthe oryzae is the causal agent of rice blast. Glycosylation plays key roles in vegetative growth,development, and infection of M. oryzae. However, several glycosylation-related genes have not been characterized.In this study, we identified a Glyco_transf_22 domain-containing protein, MoAlg9, and found that MoAlg9 islocalized to the endoplasmic reticulum(ER). Deletion of MoALG9 significantly affected conidial production, normalappressorium formation, responses to stressors, and pathogenicity of M. oryzae. We also found that the ΔMoalg9mutant was defective in glycogen utilization, appressorial penetration, and invasive growth in host cells. Moreover,we further demonstrated that MoALG9 regulates the transcription of several target genes involved in conidiation,appressorium formation, and cell wall integrity. In addition, we found that the Glyco_transf_22 domain is essentialfor normal MoAlg9 function and localization. We also provide evidence that MoAlg9 is involved in N-glycosylationpathway in M. oryzae. Taken together, these results show that MoAlg9 is important for conidiation, appressoriumformation, maintenance of cell wall integrity, and the pathogenesis of M. oryzae.
基金supported by the Project of Sanya Yazhou Bay Science and Technology City,China(SCKJ-JYRC-2022-75)the Natural Science Foundation of Hainan Province,China(322QN398).
文摘Plant pathogens secrete various cell wall-degrading enzymes that compromise host cell wall integrity and facilitate pathogen invasion.This study identified VdGH7a,a glycoside hydrolase family 7(GH7)cellobiohydrolase from Verticillium dahliae,which demonstrated hydrolytic activity against 1,4-β-glucan.Notably,VdGH7a induced cell death in Nicotiana benthamiana when signal peptides were present,though this effect was inhibited by the carbohydrate-binding type-1(CBM1)protein domain.The deletion of VdGH7a substantially reduced V.dahliae pathogenicity in cotton plants,as demonstrated by the mutants’inability to penetrate cellophane membrane.These knockout mutants also exhibited reduced carbon source utilization capacity and increased sensitivity to osmotic and cell wall stresses.Through yeast two-hybrid screening,bi-molecular fluorescence complementation(BiFC),and luciferase complementation imaging(LCI),we identified that VdGH7a interacts with an osmotin-like protein(GhOLP1)in cotton.Virus-induced gene silencing of GhOLP1 resulted in decreased salicylic acid(SA)content and reduced resistance to V.dahliae in cotton,while heterologous overexpression of GhOLP1 in Arabidopsis enhanced both resistance and SA signaling pathway gene expression.These results reveal a virulence mechanism wherein the secreted protein VdGH7a from V.dahliae interacts with GhOLP1 to activate host immunity and contribute significantly to plant resistance against V.dahliae.
基金National Science and Technology Infrastructure of China,Grant/Award Number:National Pathogen Resource Center-NPRC-32National Key Research and Development Program of China,Grant/Award Number:2023YFF0724800CAMS Innovation Fund for Medical Sciences,Grant/Award Number:2021-I2M-1-035。
文摘Background:New variants of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)continue to drive global epidemics and pose significant health risks.The pathogenicity of these variants evolves under immune pressure and host factors.Understanding these changes is crucial for epidemic control and variant research.Methods:Human angiotensin-converting enzyme 2(hACE2)transgenic mice were in-tranasally challenged with the original strain WH-09 and the variants Delta,Beta,and Omicron BA.1,while BALB/c mice were challenged with Omicron subvariants BA.5,BF.7,and XBB.1.To compare the pathogenicity differences among variants,we con-ducted a comprehensive analysis that included clinical symptom observation,meas-urement of viral loads in the trachea and lungs,evaluation of pulmonary pathology,analysis of immune cell infiltration,and quantification of cytokine levels.Results:In hACE2 mice,the Beta variant caused significant weight loss,severe lung inflammation,increased inflammatory and chemotactic factor secretion,greater mac-rophage and neutrophil infiltration in the lungs,and higher viral loads with prolonged shedding duration.In contrast,BA.1 showed a significant reduction in pathogenicity.The BA.5,BF.7,and XBB.1 variants were less pathogenic than the WH-09,Beta,and Delta variants when infected in BALB/c mice.This was evidenced by reduced weight loss,diminished pulmonary pathology,decreased secretion of inflammatory factors and chemokines,reduced macrophage and neutrophil infiltration,as well as lower viral loads in both the trachea and lungs.Conclusion:In hACE2 mice,the Omicron variant demonstrated the lowest pathogenic-ity,while the Beta variant exhibited the highest.Pathogenicity of the Delta variant was comparable to the original WH-09 strain.Among BALB/c mice,Omicron subvari-ants BA.5,BF.7,and XBB.1 showed no statistically significant differences in virulence.
文摘In Candida species,the endoplasmic reticulum(ER)stress response—regulated by the unfolded protein response(UPR)—serves as a critical adaptive mechanism affecting both pathogenicity and antifungal resistance.This review aims to synthesize current knowledge on ER stress pathways in Candida glabrata and Candida albicans,highlighting their species-specific adaptations and therapeutic implications.We systematically analyzed peer-reviewed literature on ER stress mechanisms in Candida,focusing on comparative studies of UPR signaling.Emphasis was placed on C.glabrata’s inositol-requiring enzyme 1(IRE1)-dependent Regulated IRE1-Dependent Decay(RIDD)pathway and C.albicans’IRE1/HAC1 and calcium-mediated pathways.Connections to virulence and drug resistance were evaluated through genetic,transcriptomic,and phenotypic evidence.Candida species employ divergent UPR strategies:C.glabrata mitigates ER stress primarily via RIDD-mediated mRNA decay to reduce protein load,while C.albicans enhances folding capacity through HAC1 splicing and calcium homeostasis.These adaptations promote survival in hostile host environments(e.g.,oxidative stress,immune attacks)and are linked to resistance against azoles and echinocandins.Pharmacological disruption of UPR components(e.g.,IRE1 inhibitors)sensitizes Candida to antifungals in experimental models.ER stress response pathways are promising targets for antifungal drug development.Understanding species-specific UPR mechanisms in Candida could guide novel therapies to overcome resistance and improve treatment outcomes.
基金funded by the National Key Research and Development Program of China(Grant No.2021YFD1800201).
文摘The H4 subtype of avian influenza virus(AIV)is prevalent worldwide,but only receives little attention due to its low pathogenicity in poultry.Consequently,it remains largely unclear whether H4 AIVs pose a potential threat to the poultry industry and public health.During the period from 2011 to 2022,we conducted an active surveillance programm.A total of 154,762 swab samples were collected across various provinces,and 427 H4 viruses were detected,resulting in a positivity rate of 0.28%.All H4 viruses were isolated from poultry,primarily from ducks in live poultry markets.We further investigated the genetic evolutionary characteristics and pathogenicity of 20 H4Nx viruses isolated in our program.Phylogenetic analysis revealed that the 20 H4Nx viruses belonged to the Eurasian lineage and exhibited significant genetic diversity,with 19 distinct genotypes identified.Molecular characterization indicated that these viruses were low-pathogenicity AIVs with limited binding affinity to human receptors,yet they contained mutations associated with enhanced viral replication and pathogenicity in mammals.Pathogenicity tests conducted in ducks demonstrated that H4 viruses were weakly pathogenic,exhibiting limited replication and transmission capabilities.However,some viruses were able to replicate effectively in mice and induce weight loss.For instance,DK/AH/AG61/11(H4N6)can replicate efficiently in MDCK cells,indicating a potential threat to mammals.These findings underscore the importance of ongoing surveillance of H4 AIVs to better understand their evolution and transmission dynamics and to prevent potential public health risks.
基金Supported by Key Projects in Shaoguang Institute (200402)~~
文摘[Objective] The study was to isolate and identify the pathogen of Pandora neoaphidis and to determine its pathogenicity against turnip aphid （Lipaphis erysimi）.[Method] Based on the morphological characteristics,the species of pathogenic fungus was identified.Spore shower method was used to carry out bioassay on the pathogen against turnip aphid.[Result] Primary conidia were ovoid,bitunicate and uninucleate,（24.7±1.4）μm×（10.7±0.9）μm,L/D=2.3±0.2.Secondary conidia had the similar shape with the primary ones,（18.6±2.1）μm×（13.3±1.3）μm,L/D=1.4±0.2.Hyphal body was like mycelium with the diameter of （10.6±0.8）μm.Conidiophores had palmate branch with the diameter of （10.0±0.9）μm.Pseudocystidia was not branched,which had rough base with the diameter of （19.2±1.7）μm,and gradually became more angular towards the apex with the diameter of （8.0±0.9）μm at tips.Rhizoid was like monohyphal shape with the diameter of （21.0±3.0）μm at base,the terminal apex had regular discoid holdfast.No resting spores were observed.The lethal dose of the pathogen against turnip aphid was 18.2/mm2.[Conclusion] The entomopathogenic fungus against turnip aphid was identified to be Pandora neoaphidis,and the pathogen was confirmed to have strong pathogenicity against turnip aphid.
基金Supported by Youth Foundation of Education Department in Sichuan Province (07ZB060)Youth Science and Technology Innovation Fund in Sichuan Agricultural University~~
文摘[Objective] The pathogenic Escherichia coli in musk deer was classified at molecular level to provide basic materials for molecular epidemiology of pathogenic Escherichia coli in musk deer. [Method] Plasmids from 24 pathogenic Escherichia coli in musk deer were extracted by the Lysis Triton method, and then identified by single enzyme digestion with three endonucleases of Hind Ⅲ, EcoR Ⅰ and BamH Ⅰ. [Result] The yield rate of plasmids was 91.6%, and 24 pathogenic Escherichia coli in musk deer had the identical or similar plasmid profiles. [Conclusion] Plasmid DNA analysis offers scientific basis for molecular epidemiology of pathogenic Escherichia coli in musk deer in Sichuan Institute of Musk Deer Breeding.
基金Supported by Natural Science Foundation of Jiangsu Province(BK20131334)Fund for Independent Innovation of Agricultural Science and Technology in Jiangsu Province[CX(13)3069]~~
文摘[Objective] This study aimed to investigate the genetic variation of g E gene of an epidemic pseudorabies virus（PRV） strain and its pathogenicity to piglets. [Method] By serial passage in Vero cells, a PRV strain was isolated from the brain tissues of stillborn fetuses delivered by sows with suspected PRV infection and preliminarily identified by PCR. g E gene of the isolated PRV strain was amplified and sequenced for phylogenetic analysis. In addition, the pathogenicity of the isolated PRV strain to 6-week-old piglets was evaluated. [Result] A PRV strain was successfully isolated and named PRV N5 B strain, which could proliferate in Vero cells and TCID50 of the 15 thgeneration virus liquid reached 10^7.125/0.1 ml. Specific bands could be amplified by PCR. g E gene in the isolated PRV strain was 1 740 bp in length. A phylogenetic tree was constructed based on full-length g E sequences, which showed that PRV N5 B strain and PRV strains isolated since 2012 were clustered into the same independent category and shared 99.7%-100% homology of nucleotide sequences. Compared with related sequences published previously, there were insertions of three consecutive bases at two loci. Animal experiments showed that intranasal inoculation of 6-week-old piglets with 2 ml of PRV N5 B strain（10^6/0.1 ml） led to a mortality rate of 100%. [Conclusion] In this study,genetic variability of g E gene in PRV N5 B isolate and its pathogenicity to piglets were analyzed, which provided a theoretical basis for the development of new vaccines to prevent and control porcine pseudorabies.
基金Supported by Special Project for Marine Fisheries Science and Technology and Industrial Development of Guangdong Province(A201508A05)Regional Demonstration Project of Marine Economy Innovation and Development of Guangdong Province(GD2012-A03-012)~~
文摘[Objective] The biological characteristics and pathogenicities of Shewanella algae and Shewanella abalone from Babylonia were studied in this paper. [Method]The hemolytic bacteria were isolated from the hepatopancreas of Babylonia suffered from proboscis edema with blood agar plate. The dominant bacterial community in the ill Babylonia was identified by 16 S r DNA sequence analysis, and the bacterial cultural and biochemical characteristics and pathogenicities were studied. [Result]The Shewanella bacteria, including Shewanella algae and Shewanella abalone, are the dominant bacterial community in Babylonia suffered from proboscis edema.The colony characteristics of Shewanella algae in nutrient agar medium, TCBS agar medium and CHROMagar vibrio colored medium were similar to those of Shewanella abalone. Shewanella algae possessed β-hemolysis and Shewanella abalone possessed α-hemolysis in the blood agar plate. The biochemical reaction of Shewanella algae and Shewanella abalone was all of non-fermentation type. The results of artificial infection test showed that half lethal dose（LD50） of the test strains of Shewanella algae was 10-5.50/0.1 ml. The test strains of Shewanella algae have strong toxicity, and could cause mice and chickens to die of sepsis with mortality of100%. The mortality of Babylonia infected with Shewanella algae was 10%; while the survived Babylonia lost the ability of moving and intaking for a long time, but they were not suffered from proboscis edema. There was no death in mice or chicks infected with Shewanella abalone, but their livers and spleens were slightly hyperemic and swelling. There was also no death in Babylonia infected with Shewanella abalone, but their intaking and moving ability was lost for a short time.[Conclusion] Although Shewanella algae and Shewanella abalone were the dominant bacteria in Babylonia suffered from proboscis edema, they were not the main pathogenic bacteria for proboscis edema. Shewanella algae had strong pathogenicity to mice, chicks and Babylonia, while Shewanella abalone showed no marked pathogenicity to those experimental animals in this study.
基金Supported by Science and Technology Plan Project of Yunnan Provincial Tobacco Company(2012YN06)National Natural Science Foundation of China(31160361)~~
文摘Tobacco root-knot nematode disease has caused severe damage in Geng- ma County, Yunnan Province. In order to identify the pathogenic factors of the tobac- co root-knot nematode disease in this county, the pathogenic nematodes, hosts and environment of tobacco fields in Mengsa, Hepai and Sipaishan 3 main tobacco-grow- ing towns in Gengma County were investigated and analyzed based on the local re- lated field survey on tobacco root-knot nematode disease in this county in 2012. The results showed the incidence and severity of the tobacco root-knot nematode disease were all higher than those of previous years. dominant pathogens of the tobacco root-knot The species identification showed the nematode disease were Meloidogyne arenaria and M. javanica in Gengma County. The lacking of disease-resistant culti- vars, poor management and climatic anomaly were the main causes of the tobacco root-knot nematode disease in Gengma. According to the occurrence characteristics of the disease, the agricultural prevention-based control measures were proposed.
基金Supported by Youth Foundation of Education Department in Sichuan Province(07ZB060)Scientific and Technological Supporting Project in Science and Technology Bureau of Sichuan Province(2009SZ0228)~~
文摘A multivalent inactivated Escherichia coli vaccine for forest musk deer by using serotypes O4,O26,and O139 with Al（OH）3 adjuvant was prepared.The vaccine did not cause any adverse reactions in forest musk deer.The immunogenic effects of the vaccine were experimentally investigated in pregnant and young forest musk deer.The serum antibody titers of pregnant and young forest musk deer were determined by performing the micro-agglutination test.The serum antibody titers of pregnant forest musk deer were more stable from 35th to 68th d after the third vaccination,and the serum antibody titers of four pregnant forest musk deer were maintained 25,25,25,and 24 on 68th d after the third vaccination.Young forest musk deer showed serum antibody titers which were obtained due to nursing.Young forest musk deer were administered the first intramuscular vaccine injection at an age of approximately 60 days due to a fall in maternal antibody titers.The serum antibody titers of young forest musk deer were higher after the third vaccination and maintained at approximately the same level until they were 137 days old.The maternal antibodies and the antibodies produced by young forest musk deer could be helpful for protecting the young musk deer from the infections of pathogenic Escherichia coli strains（serotypes O4,O26,and O139）for 137 days after birth（during the nursing period and the period when the forest musk deer were susceptible to diseases）.
基金Supported by Science and Technology Project of Yunnan Province(2014RA061)Special Fund for Modern Agriculture Research System for Rape of Yunnan Province~~
文摘[Objective] This study was conducted to investigate the pathogenicity of Plasmodiophora brassicae on cabbage grown under different temperature and soil pH conditions. [Method] The pathogenicity of P. brassicae were tested at seven different temperatures and at six different soil pH values with the resting spore concentration of lx108 （spores/g） in the soil. The plant survival rate and incidence rate of clubroot were investigated after 90 d. [Result] The incidence rate of clubroot on cabbage among the different temperature sets varied in a descending order as follows： 30 ℃〉25 ℃〉20 ℃〉35 ℃〉15 ℃〉10 ℃〉5 ℃ at soil pH value of 6, indicating that the pathogenicity of P. brassicae was weak at 5 and 10 ~（3. The incidence rate increased with soil temperature increasing from 15 to 30 ℃, but decreased at 35 ℃. The incidence rates of clubroot were 80.36%, 100%, 65%, 10.77%, 3.23% and 0% at soil pH 4, 5, 6, 7, 8 and 9 at 25 ℃, respectively. The growth of cabbage was inhibited and the survival rate was reduced at pH 4.The incidence rates of clubroot were low at pH value of 7 and 8, and was 0% at pH 9. The Chinese cabbage grew better at pH value of 5 and 6, but had high incidence rates of clubroot. [Conclusion] The results revealed that the incidence rate of clubroot on cabbage was closely related to the temperature and soil pH.
基金Supported by the Scientific Research and Technology Development Planning Program of Guangxi Province(10169-08)the Program for the Construction of Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection(Guikeneng1001Z014)~~
文摘[Objective] This study was to investigate the relationship between biological characteristics of Beauveria bassiana （Bals.） Vuill and pathogenicity to Bombyx rnori L, with the aim to provide scientific basis for the control of white muscardine in Bombyx mori L. [Method] The strains isolated and purified from the 6 Beauveria bassiana biocontrol agents from all over the country and the 3 white muscardine silkworms collected from Guangxi provincial silkworm rearing areas were identified by the morphological observation and molecular biology technology. The pathogenicity of B. bassaina to silkworms was determined, and the biological characteristics such as growth diameter, sporulation and the extracellular protease activity of the different B. bassiana strains were compared. [Result] The isolated 9 strains were all B. bassaina （Bals.） Vuillemin, and all strains had high pathogenicity to silkworm, but with different pathogenicities. The growth diameter, sporulation and extracellular protease activity of different B. bassiana strains were also different, and showed correlation with the patheogenicity to silkworms. [Conclusion] B. bassiana spores production amount and exocellular protease activity had significant positive correlation with their pathogenicity to silkworm.
基金supported by the Agricultural Science and Technology Innovation Program of Chinese Academy of Agricultural SciencesCentral Publicinterest Scientific Institution Basal Research Fund (No. 1610162021031).
文摘Verticillium wilt,caused by the notorious fungal pathogen Verticillium dahliae,is one of the main limiting factors for cotton production.Due to the stable dormant structure microsclerotia,long-term variability and co-evolution with host plant,its pathogenicity mechanism is very complicated,and the interaction mechanism between pathogen and host plant is also unclear.So identification and functional analysis of the genes involved in the pathogenicity or virulence of this fungus will benefit to uncover the molecular pathogenic mechanism of V.dahliae.In this review,many multifunction genes covering microsclerotia development,pathogen infection,effector proteins,transcription factors,horizontal gene transfer and trans-kingdom RNA silencing have been summarized to provide a theoretical basis to deep understand the molecular pathogenicity mechanism of V.dahliae and promote to effectively control Verticillium wilt.Furtherly,these pathogenicity-related genes may be considered as targets for effective control of Verticillium wilt in cotton.
基金supported by grants from the National Basic Research Program of China (973 Program,2005CB523200)the National High-Tech Research and Development Program of China (863 Program,2006AA10A20 4)+1 种基金the National Key Technology R&D Program (2006BAD 06A04/18/01/03)the National Natural Science Foundation of China (30470072)
文摘Since May 2006,a highly pathogenic porcine reproductive and respiratory syndrome virus （HP-PRRSV） variant characterized by 30 amino acids deletion within its NSP2-coding region emerged and caused extensive economic losses to China＇s pig industry.To investigate the in vivo pathogenicity and immune responses of the newly emerging PRRSV,3 groups of 60-d-old conventional piglets were inoculated intranasally with a representative strain of the HP-PRRSV variant HuN4 with 3 different infection doses （3×103-3×105 TCID50）.The results revealed that the virus variant caused severe disease in piglets and the significant clinical characteristics consisted of persistently high fever （41.0-41.9oC） and high morbidity and mortality （60-100%）,the marked clinical signs of PRRS and severe histopathogenic damages in multiple organs.It induced rapid and intense humoral immune responses and seroconversion was detected in most infected pigs at 7 d post-infection （DPI）.The virus vigorously replicated in vivo and the highest virus average titer was 9.7 log copies mL-1 serum at 7 DPI.Elevated levels of IFN-g and IL-10 cytokine production in serum in this study were also observed.Taken together,our results demonstrated that the HP-PRRSV variant HuN4 strain is highly pathogenic for piglets and suitable to be a reference strain of highly virulent PRRSV for evaluating the efficacy of the new vaccines.
