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1.
Science ; 373(6556): 774-779, 2021 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-34385392

RESUMO

The oomycete Phytophthora infestans is a damaging crop pathogen and a model organism to study plant-pathogen interactions. We report the discovery of a family of copper-dependent lytic polysaccharide monooxygenases (LPMOs) in plant pathogenic oomycetes and its role in plant infection by P. infestans We show that LPMO-encoding genes are up-regulated early during infection and that the secreted enzymes oxidatively cleave the backbone of pectin, a charged polysaccharide in the plant cell wall. The crystal structure of the most abundant of these LPMOs sheds light on its ability to recognize and degrade pectin, and silencing the encoding gene in P. infestans inhibits infection of potato, indicating a role in host penetration. The identification of LPMOs as virulence factors in pathogenic oomycetes opens up opportunities in crop protection and food security.


Assuntos
Lycopersicon esculentum/parasitologia , Oxigenases de Função Mista/metabolismo , Pectinas/metabolismo , Phytophthora infestans/enzimologia , Doenças das Plantas/parasitologia , Solanum tuberosum/parasitologia , Cobre , Oxigenases de Função Mista/química , Oxigenases de Função Mista/genética , Modelos Moleculares , Oxirredução , Phytophthora infestans/genética , Phytophthora infestans/patogenicidade , Folhas de Planta/parasitologia , Polissacarídeos/metabolismo , Conformação Proteica , Domínios Proteicos , Fatores de Virulência/química , Fatores de Virulência/genética , Fatores de Virulência/metabolismo
2.
Clin Lab ; 67(8)2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-34383413

RESUMO

BACKGROUND: To investigate the distribution of virulence genes exoS and exoU of Pseudomonas aeruginosa type III secretion system and their antimicrobial resistance characteristics in Xinjiang Province. METHODS: A total of 228 isolates of Pseudomonas aeruginosa were collected from January 2017 to April 2017 in our hospital. The VITEK2-compac system was used for strain identification and antimicrobial susceptibility test. The disk diffusion method was used for antimicrobial susceptibility supplementation. PCR method was used for detection of exoS and exoU virulence gene. RESULTS: Among 228 isolates of Pseudomonas aeruginosa, 178 (78.07%) were positive for exoS gene, 91 (39.91%) were positive for exoU gene, and 21.49% of the isolates carried both genes (exoU+/exoS+). A total of 30 MDR strains were detected, accounting for 13.16%. The antimicrobial resistance of the exoU+ group was 76.67%, which was significantly higher than that of the exoU-group (23.33%). The difference was statistically significant (p < 0.001). The detection rate of fluoroquinolone-insensitive strains in exoU+ group was as high as 57.45%, which was significantly higher than 42.55% in exoU-group and the difference was statistically significant (p < 0.05). The 30-day mortality rate of the exoU+ group was 8.79%, which was higher than that of the exoU-group (4.38%), and the difference was statistically significant (p < 0.05). CONCLUSIONS: The expression of exoU gene is associated with multidrug resistance, fluoroquinolone resistance, and prognosis. We should enhance the detection of drug resistance and study the pathogenesis and regulation mecha-nism of T3SS, in order to provide new ideas for the design of reasonable treatment strategies and the development of new therapeutic drugs.


Assuntos
Infecções por Pseudomonas , Pseudomonas aeruginosa , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Proteínas de Bactérias/genética , Genótipo , Humanos , Infecções por Pseudomonas/diagnóstico , Infecções por Pseudomonas/tratamento farmacológico , Pseudomonas aeruginosa/genética , Sistemas de Secreção Tipo III/genética , Virulência/genética , Fatores de Virulência/genética
3.
Microb Pathog ; 159: 105134, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34400283

RESUMO

Aeromonas veronii (A. veronii, AV) strains are emerging zoonotic and aquatic pathogens, yet we know very little about their genomics. This study aims to utilize comparative genomics to investigate the intraspecific genetic diversity, differences in virulence factors and evolutionary mechanisms of A. veronii strains from diverse sources and to fundamentally demonstrate their pathogenic mechanisms. We conducted comparative genomics analysis of 39 A. veronii strains from different sources and found that 1993 core genes are shared by these strains and that these shared core genes may be necessary to maintain the basic characteristics of A. veronii. Additionally, phylogenetic relationship analysis based on these shared genes revealed that a distant relationship between the AMC34 strain and the other 38 strains but that, the genetic relationship among the 38 strains is relatively close, indicating that AMC34 may not belong to A. veronii. Furthermore, analysis of shared core genes and average nucleotide identity (ANI) values showed no obvious correlation with the location of A. veronii isolation and genetic relationship. Our research indicates the evolutionary mechanism of A. veronii from different sources and provides new insights for a deeper understanding of its pathogenic mechanism.


Assuntos
Aeromonas , Infecções por Bactérias Gram-Negativas , Aeromonas/genética , Aeromonas veronii/genética , Genômica , Humanos , Filogenia , Fatores de Virulência/genética
4.
Nat Commun ; 12(1): 4613, 2021 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-34326342

RESUMO

R-bodies are long, extendable protein polymers formed in the cytoplasm of some bacteria; they are best known for their role in killing of paramecia by bacterial endosymbionts. Pseudomonas aeruginosa PA14, an opportunistic pathogen of diverse hosts, contains genes (referred to as the reb cluster) with potential to confer production of R-bodies and that have been implicated in virulence. Here, we show that products of the PA14 reb cluster associate with R-bodies and control stochastic expression of R-body structural genes. PA14 expresses reb genes during colonization of plant and nematode hosts, and R-body production is required for full virulence in nematodes. Analyses of nematode ribosome content and immune response indicate that P. aeruginosa R-bodies act via a mechanism involving ribosome cleavage and translational inhibition. Our observations provide insight into the biology of R-body production and its consequences during P. aeruginosa infection.


Assuntos
Proteínas de Bactérias/metabolismo , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/metabolismo , Pseudomonas aeruginosa/patogenicidade , Fatores de Virulência/metabolismo , Animais , Proteínas de Bactérias/genética , Biofilmes/crescimento & desenvolvimento , Caenorhabditis elegans , Filogenia , Infecções por Pseudomonas/genética , Infecções por Pseudomonas/metabolismo , Pseudomonas aeruginosa/citologia , Pseudomonas aeruginosa/genética , Virulência , Fatores de Virulência/genética
5.
Sci Total Environ ; 794: 148760, 2021 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-34323773

RESUMO

Aquaculture ecosystem has become a hotspot of antibiotics resistance genes (ARGs) dissemination, owing to the abuse of prophylactic antibiotics. However, it is still unclear how and to what extent ARGs respond to the increasing antibiotic pollution, a trend as expected and as has occurred. Herein, a significant sediment antibiotic pollution gradient was detected along a drainage ditch after decades of shrimp aquaculture. The increasing antibiotic pollution evidently promoted the diversities and tailored the community structures of ARGs, mobile genetic elements (MGEs), virulence factors and pathogens. The profiles of ARGs and MGEs were directly altered by the concentrations of terramycin and sulphadimidine. By contrast, virulence factors were primarily affected by nutrient variables in sediment. The pathogens potentially hosted diverse virulence factors and ARGs. More than half of the detected ARGs subtypes non-linearly responded to increasing antibiotic pollution, as supported by significant tipping points. However, we screened seven antibiotic concentration discriminatory ARGs that could serve as independent variable for quantitatively diagnosing total antibiotic concentration. Co-occurrence analysis depicted that notorious aquaculture pathogens of Vibrio harveyi and V. parahaemolyticus potentially hosted ARGs that confer resistance to multiple antibiotics, while priority pathogens for humankind, e.g., Helicobacter pylori and Staphylococcus aureus, could have harbored redundant virulence factors. Collectively, the significant tipping points and antibiotic concentration-discriminatory ARGs may translate into warning index and diagnostic approach for diagnosing antibiotic pollution. Our findings provided novel insights into the interplay among ARGs, MGEs, pathogens, virulence factors and geochemical variables under the scenario of increasing antibiotic pollution.


Assuntos
Antibacterianos , Genes Bacterianos , Ecossistema , Vibrio , Fatores de Virulência/genética
6.
Nat Commun ; 12(1): 4188, 2021 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-34234121

RESUMO

Klebsiella pneumoniae is a leading cause of antimicrobial-resistant (AMR) healthcare-associated infections, neonatal sepsis and community-acquired liver abscess, and is associated with chronic intestinal diseases. Its diversity and complex population structure pose challenges for analysis and interpretation of K. pneumoniae genome data. Here we introduce Kleborate, a tool for analysing genomes of K. pneumoniae and its associated species complex, which consolidates interrogation of key features of proven clinical importance. Kleborate provides a framework to support genomic surveillance and epidemiology in research, clinical and public health settings. To demonstrate its utility we apply Kleborate to analyse publicly available Klebsiella genomes, including clinical isolates from a pan-European study of carbapenemase-producing Klebsiella, highlighting global trends in AMR and virulence as examples of what could be achieved by applying this genomic framework within more systematic genomic surveillance efforts. We also demonstrate the application of Kleborate to detect and type K. pneumoniae from gut metagenomes.


Assuntos
Proteínas de Bactérias/genética , Infecção Hospitalar/microbiologia , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/genética , Tipagem Molecular/métodos , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Infecção Hospitalar/diagnóstico , Infecção Hospitalar/tratamento farmacológico , Infecção Hospitalar/epidemiologia , Conjuntos de Dados como Assunto , Farmacorresistência Bacteriana Múltipla/genética , Monitoramento Epidemiológico , Microbioma Gastrointestinal/genética , Genoma Bacteriano , Humanos , Lactente , Recém-Nascido , Infecções por Klebsiella/diagnóstico , Infecções por Klebsiella/tratamento farmacológico , Infecções por Klebsiella/epidemiologia , Klebsiella pneumoniae/isolamento & purificação , Klebsiella pneumoniae/patogenicidade , Metagenoma/genética , Epidemiologia Molecular/métodos , Mutação , Filogenia , Software , Virulência/genética , Fatores de Virulência/genética , Sequenciamento Completo do Genoma , beta-Lactamases/genética
7.
BMC Infect Dis ; 21(1): 627, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-34210263

RESUMO

BACKGROUND AND OBJECTIVE: Carriage of virulence factors confers some evolutionary benefit to bacteria, which favors the resistant strains. We aimed to analyze whether antibiotic susceptibility of Staphylococcus aureus strains is affected by agr typing, biofilm formation ability, and virulence profiles. METHODS: A total of 123 S. aureus clinical isolates were subjected to antimicrobial susceptibility testing by disk diffusion method, biofilm formation by microtiter plate method, as well as polymerase chain reaction screening to identify virulence genes and the accessory gene regulator (agr) types I-IV. A P value < 0.05 was considered significant. RESULTS: The most prevalent virulence gene was staphyloxanthin crtN, followed by hemolysin genes, capsular cap8H, toxic shock toxin tst, and enterotoxin sea, respectively. Resistant isolates were more commonly found in the agr-negative group than in the agr-positive group. Isolates of agr type III were more virulent than agr I isolates. Strong biofilm producers showed more antibiotic susceptibility and carried more virulence genes than non-strong biofilm producers. Associations were found between the presence of virulence genes and susceptibility to antibiotics. Carriage of the virulence genes and agr was higher in the inpatients; while, resistance and strong biofilms were more prevalent in the outpatients. CONCLUSION: These findings indicated the presence of several virulence factors, biofilm production capacity, agr types and resistance to antibiotics in clinical S. aureus isolates. Considering the importance of S. aureus for human medicine, an understanding of virulence and resistance relationships would help to reduce the impact of S. aureus infections.


Assuntos
Proteínas de Bactérias , Biofilmes , Staphylococcus aureus/genética , Staphylococcus aureus/isolamento & purificação , Staphylococcus aureus/fisiologia , Staphylococcus aureus/patogenicidade , Transativadores , Fatores de Virulência/genética , Toxinas Bacterianas/genética , Farmacorresistência Bacteriana , Enterotoxinas/genética , Exfoliatinas/genética , Feminino , Proteínas Hemolisinas/genética , Humanos , Masculino , Testes de Sensibilidade Microbiana , Fenótipo , Reação em Cadeia da Polimerase , Superantígenos/genética , Xantofilas
8.
Int J Mol Sci ; 22(11)2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-34205995

RESUMO

The increasing spread of multidrug-resistant pathogenic bacteria is one of the major threats to public health worldwide. Bacteria can acquire antibiotic resistance and virulence genes through horizontal gene transfer (HGT). A novel horizontal gene transfer mechanism mediated by outer membrane vesicles (OMVs) has been recently identified. OMVs are rounded nanostructures released during their growth by Gram-negative bacteria. Biologically active toxins and virulence factors are often entrapped within these vesicles that behave as molecular carriers. Recently, OMVs have been reported to contain DNA molecules, but little is known about the vesicle packaging, release, and transfer mechanisms. The present review highlights the role of OMVs in HGT processes in Gram-negative bacteria.


Assuntos
Proteínas da Membrana Bacteriana Externa/genética , Membrana Externa Bacteriana/metabolismo , Técnicas de Transferência de Genes , Transferência Genética Horizontal/genética , Bactérias/genética , Bactérias/patogenicidade , Humanos , Fatores de Virulência/genética , Fatores de Virulência/metabolismo
9.
BMC Genomics ; 22(1): 522, 2021 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-34238216

RESUMO

BACKGROUND: Streptococcus intermedius, a member of the S. anginosus group, is a commensal bacterium present in the normal microbiota of human mucosal surfaces of the oral, gastrointestinal, and urogenital tracts. However, it has been associated with various infections such as liver and brain abscesses, bacteremia, osteo-articular infections, and endocarditis. Since 2005, high throughput genome sequencing methods enabled understanding the genetic landscape and diversity of bacteria as well as their pathogenic role. Here, in order to determine whether specific virulence genes could be related to specific clinical manifestations, we compared the genomes from 27 S. intermedius strains isolated from patients with various types of infections, including 13 that were sequenced in our institute and 14 available in GenBank. RESULTS: We estimated the theoretical pangenome size to be of 4,020 genes, including 1,355 core genes, 1,054 strain-specific genes and 1,611 accessory genes shared by 2 or more strains. The pangenome analysis demonstrated that the genomic diversity of S. intermedius represents an "open" pangenome model. We identified a core virulome of 70 genes and 78 unique virulence markers. The phylogenetic clusters based upon core-genome sequences and SNPs were independent from disease types and sample sources. However, using Principal Component analysis based on presence/ absence of virulence genes, we identified the sda histidine kinase, adhesion protein LAP and capsular polysaccharide biosynthesis protein cps4E as being associated to brain abscess or broncho-pulmonary infection. In contrast, liver and abdominal abscess were associated to presence of the fibronectin binding protein fbp54 and capsular polysaccharide biosynthesis protein cap8D and cpsB. CONCLUSIONS: Based on the virulence gene content of 27 S. intermedius strains causing various diseases, we identified putative disease-specific genetic profiles discriminating those causing brain abscess or broncho-pulmonary infection from those causing liver and abdominal abscess. These results provide an insight into S. intermedius pathogenesis and highlights putative targets in a diagnostic perspective.


Assuntos
Genômica , Streptococcus intermedius , Genoma Bacteriano , Humanos , Filogenia , Streptococcus intermedius/genética , Virulência/genética , Fatores de Virulência/genética
10.
Biomed Environ Sci ; 34(6): 454-464, 2021 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-34284853

RESUMO

Objective: This study was performed to compare the genetic diversity, virulence, and antimicrobial resistance of Aeromonas strains isolated from patients and healthy individuals. Methods: A total of 38 clinical strains and 19 strains from healthy individuals were isolated from the samples collected in Ma'anshan City, Anhui Province. Their taxonomy was investigated using concatenated gyrB- cpn60 sequences, and their resistance to 12 antibiotics was evaluated. The pathogenicity of these strains was examined through beta-hemolysis, protease activity, and virulence gene assays. Results: The 57 Aeromonas strains were divided into 55 sequence types. Of these types, 21 were novel, suggesting that their genetic diversity was high. These Aeromonas isolates could be divided into 7 species, and the positive rates of beta-hemolysis and protease activity were 49.1% and 73.7%, respectively. The detection rate of clinical patients in terms of beta-hemolysis and protease activity was higher than that of healthy individuals. Among the four most common Aeromonas strains, A. dhakensis had the highest detection rate of virulence genes. The multidrug resistance rate of the clinical isolates was much higher than that of the strains isolated from healthy individuals. Conclusions: The taxonomy, virulence properties, and antibiotic resistance of Aeromonas isolates from patients differ from those of the isolates from healthy individuals.


Assuntos
Aeromonas/genética , Farmacorresistência Bacteriana/genética , Aeromonas/isolamento & purificação , Aeromonas/patogenicidade , Estudos de Casos e Controles , Variação Genética , Humanos , Fatores de Virulência/genética
11.
Microb Pathog ; 158: 105098, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34280499

RESUMO

Proteus mirabilis is an opportunistic pathogen associated with a variety of infections in humans, especially those in the urinary tract. The isolation of this pathogen in foods of animal origin such as meat is poorly documented and should not be neglected, in view of the zoonotic risk that this can pose to human health. Thus, the objective of this study was to evaluate the prevalence, virulence profile, and similarity between P. mirabilis strains isolated from chicken, beef, and pork meat and those causing community-acquired urinary tract infections (UTI-CA), in order to better understand the role of this bacterium as a zoonotic pathogen. P. mirabilis was isolated from the three types of meat and was found to be more prevalent in chicken. All isolates exhibited several genotypic and phenotypic virulence characteristics, such as adhesion capacity in HEp-2 cell culture, biofilm formation, cytotoxicity in Vero cells and genes that express fimbriae (mrpA, pmfA, ucaA, atfA), hemolysin (hpmA), proteases (zapA and ptA) and siderophore receptor (ireA). UTI-CA strains showed a higher prevalence of ucaA and ireA genes, whereas those from the chicken meat had a higher prevalence of the atfA gene compared with the isolates from the beef and pork meat. It was observed that chicken meat and UTI-CA strains mainly formed very strong biofilms, whereas strains isolated from beef and pork formed more weak and moderate biofilms. Several strains from meat showed close genetic similarity to those from UTI-CA and had the same virulence profiles. Thus, meats may be an important source of the dissemination of P. mirabilis responsible for causing UTIs in the community.


Assuntos
Carne de Porco , Carne Vermelha , Infecções Urinárias , Animais , Bovinos , Galinhas , Chlorocebus aethiops , Humanos , Carne , Proteus mirabilis/genética , Suínos , Células Vero , Fatores de Virulência/genética
12.
ACS Infect Dis ; 7(8): 2445-2454, 2021 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-34265205

RESUMO

Enterococcal cytolysin is a hemolytic virulence factor linked to human disease and increased patient mortality. Produced by pathogenic strains of Enterococcus faecalis, cytolysin is made up of two small, post-translationally modified peptides called CylLL" and CylLS". They exhibit a unique toxicity profile where lytic activity is observed for both mammalian cells and Gram-positive bacteria that is dependent on the presence of both peptides. In this study, we performed alanine substitution of all residues in CylLL" and CylLS" and determined the effect on both activities. We identified key residues involved in overall activity and residues that dictate cell type specificity. All (methyl)lanthionines as well as a Gly-rich hinge region were critical for both activities. In addition, we investigated the binding of the two subunits to bacterial cells suggesting that the large subunit CylLL" has stronger affinity for the membrane or a target molecule therein. Genome mining identified other potential two-component lanthipeptides and provided insights into potential evolutionary origins.


Assuntos
Enterococcus faecalis , Enterococcus , Animais , Citotoxinas , Enterococcus faecalis/genética , Humanos , Relação Estrutura-Atividade , Fatores de Virulência/genética
13.
J Infect Chemother ; 27(11): 1571-1577, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34217606

RESUMO

OBJECTIVE: We evaluated biofilm production ability (BPA) of Streptococcus agalactiae isolates from companion animals/humans and clarified the relationship between BPA populations and other microbiological features. METHODS: Companion animal-/human-origin isolates were collected with host information. We measured BPA using crystal violet staining, via virulence-associated gene profiling (hylB-pavA-pilB-spb1-srtC1-brpA), capsular genotyping, multilocus sequence typing, and antimicrobial resistance (AMR) phenotyping/genotyping. Significant difference in BPA of isolates from different hosts was assessed. We analyzed the association between BPA populations and the virulence genotypes, capsular genotypes, sequence types/clonal complexes, and AMR phenotypes/genotypes. Inhibitory effect of berberine on BPA was evaluated. RESULTS: Five, twenty-six, and twenty-six isolates belonged to strong, moderate, and weak biofilm producers, whereas seventeen showed no biofilm production. We defined strong, moderate, or weak biofilm producers as the producer group (n = 57) to conduct a comparative analysis between the producer and non-producer populations. There was a significant correlation between the producer population and vaginal specimen. We found significant associations between the producer group and presence (57.9%) of pilB and between the non-producer population and presence (70.6%) of spb1. There was no association between the producer group and capsular genotypes, sequence types/clonal complexes, and AMR phenotypes/genotypes (except for a significant correlation between the producer group and AMR to minocycline). We confirmed inhibitory effect of berberine at sub-minimum inhibitory concentrations (MICs) against the type strain on BPA. CONCLUSION: Our observations suggest that S. agalactiae harboring pilB is more capable of producing biofilms, with berberine inhibitory effect at sub-MICs on BPA.


Assuntos
Animais de Estimação , Streptococcus agalactiae , Animais , Antibacterianos/farmacologia , Biofilmes , Feminino , Genótipo , Humanos , Testes de Sensibilidade Microbiana , Streptococcus agalactiae/genética , Fatores de Virulência/genética
14.
Nat Commun ; 12(1): 4049, 2021 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-34193873

RESUMO

Xyloglucans are highly substituted and recalcitrant polysaccharides found in the primary cell walls of vascular plants, acting as a barrier against pathogens. Here, we reveal that the diverse and economically relevant Xanthomonas bacteria are endowed with a xyloglucan depolymerization machinery that is linked to pathogenesis. Using the citrus canker pathogen as a model organism, we show that this system encompasses distinctive glycoside hydrolases, a modular xyloglucan acetylesterase and specific membrane transporters, demonstrating that plant-associated bacteria employ distinct molecular strategies from commensal gut bacteria to cope with xyloglucans. Notably, the sugars released by this system elicit the expression of several key virulence factors, including the type III secretion system, a membrane-embedded apparatus to deliver effector proteins into the host cells. Together, these findings shed light on the molecular mechanisms underpinning the intricate enzymatic machinery of Xanthomonas to depolymerize xyloglucans and uncover a role for this system in signaling pathways driving pathogenesis.


Assuntos
Parede Celular/metabolismo , Citrus/microbiologia , Glucanos/metabolismo , Glicosídeo Hidrolases/metabolismo , Fatores de Virulência/genética , Xanthomonas/metabolismo , Xilanos/metabolismo , Proteínas de Bactérias/metabolismo , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Ativação Transcricional , Sistemas de Secreção Tipo III/metabolismo , Fatores de Virulência/metabolismo , Xanthomonas/genética , Xanthomonas/patogenicidade
15.
Int J Mol Sci ; 22(14)2021 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-34298948

RESUMO

Verticillium wilt, caused by Verticillium dahliae, is a devastating disease for many important crops, including cotton. Kiwellins (KWLs), a group of cysteine-rich proteins synthesized in many plants, have been shown to be involved in response to various phytopathogens. To evaluate genes for their function in resistance to Verticillium wilt, we investigated KWL homologs in cotton. Thirty-five KWL genes (GhKWLs) were identified from the genome of upland cotton (Gossypium hirsutum). Among them, GhKWL1 was shown to be localized in nucleus and cytosol, and its gene expression is induced by the infection of V. dahliae. We revealed that GhKWL1 was a positive regulator of GhERF105. Silencing of GhKWL1 resulted in a decrease, whereas overexpression led to an increase in resistance of transgenic plants to Verticillium wilt. Interestingly, through binding to GhKWL1, the pathogenic effector protein VdISC1 produced by V. dahliae could impair the defense response mediated by GhKWL1. Therefore, our study suggests there is a GhKWL1-mediated defense response in cotton, which can be hijacked by V. dahliae through the interaction of VdISC1 with GhKWL1.


Assuntos
Ascomicetos , Proteínas Fúngicas , Regulação Fúngica da Expressão Gênica , Gossypium , Doenças das Plantas , Fatores de Transcrição , Regulação para Cima , Fatores de Virulência , Ascomicetos/genética , Ascomicetos/metabolismo , Ascomicetos/patogenicidade , Proteínas Fúngicas/biossíntese , Proteínas Fúngicas/genética , Gossypium/genética , Gossypium/metabolismo , Gossypium/microbiologia , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Fatores de Transcrição/biossíntese , Fatores de Transcrição/genética , Fatores de Virulência/biossíntese , Fatores de Virulência/genética
16.
Int J Mol Sci ; 22(14)2021 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-34298965

RESUMO

Pectobacterium parmentieri is a Gram-negative plant-pathogenic bacterium able to infect potato (Solanum tuberosum L.). Little is known about lytic bacteriophages infecting P. parmentieri and how phage-resistance influences the environmental fitness and virulence of this species. A lytic phage vB_Ppp_A38 (ϕA38) has been previously isolated and characterized as a potential biological control agent for the management of P. parmentieri. In this study, seven P. parmentieri SCC 3193 Tn5 mutants were identified that exhibited resistance to infection caused by vB_Ppp_A38 (ϕA38). The genes disrupted in these seven mutants encoded proteins involved in the assembly of O-antigen, sugar metabolism, and the production of bacterial capsule exopolysaccharides. The potential of A38-resistant P. parmentieri mutants for plant colonization and pathogenicity as well as other phenotypes expected to contribute to the ecological fitness of P. parmentieri, including growth rate, use of carbon and nitrogen sources, production of pectinolytic enzymes, proteases, cellulases, and siderophores, swimming and swarming motility, presence of capsule and flagella as well as the ability to form biofilm were assessed. Compared to the wild-type P. parmentieri strain, all phage-resistant mutants exhibited a reduced ability to colonize and to cause symptoms in growing potato (S. tuberosum L.) plants. The implications of bacteriophage resistance on the ecological fitness of P. parmentieri are discussed.


Assuntos
Bacteriófagos , Regulação Bacteriana da Expressão Gênica , Mutação , Pectobacterium , Doenças das Plantas/microbiologia , Polissacarídeos Bacterianos , Solanum tuberosum/microbiologia , Fatores de Virulência/biossíntese , Bacteriófagos/genética , Bacteriófagos/metabolismo , Pectobacterium/genética , Pectobacterium/metabolismo , Pectobacterium/patogenicidade , Pectobacterium/virologia , Polissacarídeos Bacterianos/genética , Polissacarídeos Bacterianos/metabolismo , Fatores de Virulência/genética
17.
Int J Mol Sci ; 22(12)2021 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-34204265

RESUMO

Human epidermal growth factor receptor 2 (HER-2) is overexpressed in many malignant tumors. The anti-HER2 antibody trastuzumab has been approved for treating HER2-positive early and metastatic breast cancers. Pseudomonas exotoxin A (PE), a bacterial toxin of Pseudomonas aeruginosa, consists of an A-domain with enzymatic activity and a B-domain with cell binding activity. Recombinant immunotoxins comprising the HER2(scFv) single-chain Fv from trastuzumab and the PE24B catalytic fragment of PE display promising cytotoxic effects, but immunotoxins are typically insoluble when expressed in the cytoplasm of Escherichia coli, and thus they require solubilization and refolding. Herein, a recombinant immunotoxin gene was fused with maltose binding protein (MBP) and overexpressed in a soluble form in E. coli. Removal of the MBP yielded stable HER2(scFv)-PE24B at 91% purity; 0.25 mg of pure HER2(scFv)-PE24B was obtained from a 500 mL flask culture. Purified HER2(scFv)-PE24B was tested against four breast cancer cell lines differing in their surface HER2 level. The immunotoxin showed stronger cytotoxicity than HER2(scFv) or PE24B alone. The IC50 values for HER2(scFv)-PE24B were 28.1 ± 2.5 pM (n = 9) and 19 ± 1.4 pM (n = 9) for high HER2-positive cell lines SKBR3 and BT-474, respectively, but its cytotoxicity was lower against MDA-MB-231 and MCF7. Thus, fusion with MBP can facilitate the soluble expression and purification of scFv immunotoxins.


Assuntos
ADP Ribose Transferases , Antineoplásicos Imunológicos/farmacologia , Toxinas Bacterianas , Exotoxinas , Imunotoxinas/farmacologia , Proteínas Ligantes de Maltose , Receptor ErbB-2/antagonistas & inibidores , Proteínas Recombinantes de Fusão/farmacologia , Anticorpos de Cadeia Única , Fatores de Virulência , ADP Ribose Transferases/genética , Toxinas Bacterianas/genética , Linhagem Celular Tumoral , Sobrevivência Celular , Relação Dose-Resposta a Droga , Escherichia coli/genética , Escherichia coli/metabolismo , Exotoxinas/genética , Expressão Gênica , Engenharia Genética , Vetores Genéticos/genética , Humanos , Imunotoxinas/genética , Imunotoxinas/isolamento & purificação , Proteínas Ligantes de Maltose/genética , Espectrometria de Massas , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/isolamento & purificação , Anticorpos de Cadeia Única/genética , Fatores de Virulência/genética
18.
Arch Microbiol ; 203(7): 4663-4675, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34175964

RESUMO

Quorum sensing (QS) represents a major target for reducing bacterial pathogenicity and antibiotic resistance. This study identifies bergamot and aspidosperma as new potential sources of anti-QS agents. We investigated the anti-QS activity of plant materials on both Chromobacterium violaceum and Pseudomonas aeruginosa. Initially, we determined the minimum inhibitory concentrations (MICs) of plant materials using a broth microdilution method. Subsequently, we tested the effect of sub-MIC concentrations on QS-regulated traits and virulence factors production in test bacteria. Results revealed that bergamot and aspidosperma inhibited the ability of C. violaceum to produce violacein. Other QS-controlled phenotypes of C. violaceum, namely chitinolytic activity, motility, and biofilm formation, were also reduced by both plant materials. Moreover, QS-linked traits of P. aeruginosa were also reduced. Bergamot inhibited swarming but not swimming motility, while aspidosperma diminished both motility types in P. aeruginosa. Both plant materials also demonstrated antibiofilm activity and inhibited the production of protease and pyocyanin in P. aeruginosa. Furthermore, we tested the anti-QS effect of plant materials on the transcriptional level using RT-qPCR. Bergamot dramatically downregulated the C. violaceum autoinducer synthase gene cviI and the vioB gene involved in violacein biosynthesis, confirming the phenotypic observation on its anti-QS activity. Aspidosperma also reduced the expression of cviI and vioB but less drastically than bergamot. In P. aeruginosa, downregulation in the transcripts of the QS genes lasI, lasR, rhlI, and rhlR was also achieved by bergamot and aspidosperma. Therefore, data in the present study suggest the usefulness of bergamot and aspidosperma as sources of antivirulence agents.


Assuntos
Aspidosperma , Chromobacterium , Extratos Vegetais , Óleos Vegetais , Pseudomonas aeruginosa , Percepção de Quorum , Antibacterianos/farmacologia , Aspidosperma/química , Biofilmes/efeitos dos fármacos , Chromobacterium/efeitos dos fármacos , Chromobacterium/genética , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Extratos Vegetais/farmacologia , Óleos Vegetais/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/genética , Percepção de Quorum/efeitos dos fármacos , Percepção de Quorum/genética , Fatores de Virulência/genética
19.
Arch Microbiol ; 203(7): 4351-4359, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34110479

RESUMO

Multidrug-resistant (MDR) and hypervirulent Klebsiella pneumoniae (hvKp) clones have become a major threat to global public health. The clonal group 258 (CG258) is considered a high-risk CG and the K. pneumoniae strains belonging to it are often multi-resistant and to spread mainly in the hospital environment. This study aimed to characterize the antimicrobial resistance profile, virulence factors, and the clonal relationships among 13 K. pneumoniae strains belonging to CG258 from patients admitted to a tertiary hospital in Teresina, in the state of Piauí, northeastern Brazil. Ten strains were classified as MDR and three as extensively drug-resistant (XDR). Three different ß-lactamase-encoding genes (blaKPC, blaOXA-1-like, and blaCTX-M-Gp1) and six virulence genes (fimH, ycfM, mrkD, entB, ybtS, and kfu) were detected. Moreover, two hypermucoviscous K. pneumoniae strains and one capsular K-type 2 were found. Multilocus sequence typing analysis revealed ten different sequence types (STs) (ST14, ST17, ST20, ST29, ST45, ST101, ST268, ST1800, ST3995, and ST3996) belonging to CG258, being two (ST3995 and ST3996) described for the first time in this study.


Assuntos
Farmacorresistência Bacteriana , Infecções por Klebsiella , Klebsiella pneumoniae , Fatores de Virulência , Antibacterianos/farmacologia , Brasil , Farmacorresistência Bacteriana/genética , Humanos , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/classificação , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/patogenicidade , Testes de Sensibilidade Microbiana , Tipagem de Sequências Multilocus , Fatores de Virulência/genética
20.
Curr Microbiol ; 78(8): 2980-2988, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34089354

RESUMO

This study aimed to compare the genotype diversity of C. jejuni isolates. From the total of 64 C. jejuni strains evaluated, 44 were isolated from broiler carcasses (2015-2016) and 20 from hospitalized patients with gastroenteritis caused by the microorganism (2000-2006). The strains were correlated for the presence of flaA, pldA, cadF, ciaB, cdtABC, luxS, dnaJ, cbrA, htrA, pVir, Hcp, cstII, and neuA genes by PCR (polymerase chain reaction) and for phylogenetic proximity by PFGE (pulsed-field gel electrophoresis). Of the total strains studied, 28 (43.7%) presented all the studied genes, except pVir. Among these strains, 25 (89.3%) were of poultry origin. Poultry strains showed a higher prevalence (P < 0.05) of genes linked to adhesion, colonization, invasion, cytotoxicity, biofilm formation, and adaptation to adverse conditions. Additionally, the profile that denotes the presence of all genes identified in the study (P1) was identified in 56.8% of poultry strains and in 15.0% of human strains. Molecular typing analysis identified five pulsotypes, none of which grouped strains from different origins. Although human strains were from hospitalized patients, they presented limited virulence capacity and adaptability to adverse conditions compared to chicken carcasses, besides being different in molecular typing. However, the ability to cause Guillain-Barré Syndrome is equal for both strains. In general, poultry strains, being more recent, are more specialized to adapt to the environment, invade, and cause disease in the human host.


Assuntos
Infecções por Campylobacter , Campylobacter jejuni , Doenças das Aves Domésticas , Animais , Infecções por Campylobacter/veterinária , Campylobacter jejuni/genética , Galinhas , Eletroforese em Gel de Campo Pulsado , Humanos , Filogenia , Aves Domésticas , Fatores de Virulência/genética
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