Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 1.916
Filter
1.
Chinese Journal of Biotechnology ; (12): 177-189, 2024.
Article in Chinese | WPRIM | ID: wpr-1008088

ABSTRACT

Iron is an essential element for living organisms that plays critical roles in the process of bacterial growth and metabolism. However, it remains to be elucidated whether piuB encoding iron-uptake factor is involved in iron uptake and pathogenicity of Xanthomonas axonopodis pv. glycines (Xag). To investigate the function of piuB, we firstly generated a piuB deletion mutant (ΔpiuB) by homologous recombination. Compared with the wild-type, the piuB mutant exhibited significantly reduced growth and virulence in host soybean. The mutant displayed markedly increased siderophore secretory volume, and its sensitivity to Fe3+, Cu2+, Zn2+ and Mn2+ was significantly enhanced. Additionally, the H2O2 resistance, exopolysaccharide yield, biofilm formation, and cell mobility of ΔpiuB were significantly diminished compared to that of the wild-type. The addition of exogenous Fe3+ cannot effectively restore the above characteristics of ΔpiuB. However, expressing piuB in trans rescued the properties lost by ΔpiuB to the levels in the wild-type. Taken together, our results demonstrated that PiuB is a potential factor for Xag to assimilate Fe3+, and is necessary for Xag to be pathogenic in host soybean.


Subject(s)
Iron , Glycine max , Virulence , Xanthomonas axonopodis/genetics , Hydrogen Peroxide
2.
Chinese Journal of Preventive Medicine ; (12): 229-235, 2023.
Article in Chinese | WPRIM | ID: wpr-969871

ABSTRACT

Objective: To explore the relationship between extracellular enzymes activity and virulence of Candida glabrata clinical isolates based on the infection model of Galleria mellonella larvae. Methods: Using experimental research methods, 71 strains of non-repetitive Candida glabrata were collected from Qinghai Provincial People's Hospital from June 2021 to January 2022. Bovine serum protein agar medium, egg yolk agar medium, sheep blood agar medium, Tween-80 agar medium and triglyceride agar medium were used to detect the aspartyl protease activity, phospholipase activity, hemolysis activity, esterase activity and lipase activity of Candida glabrata. Median lethal concentration (LC50) was calculated by using 1.25×108 CFU/ml,2.50×108 CFU/ml,3.75×108 CFU/ml,5.00×108 CFU/ml suspension of Candida glabrata ATCC2001 to infect Galleria mellonella larvae. Histopathological and etiological analysis was performed to determine whether the infection model was successfully established. The clinical isolates of Candida glabrata were configured to infect Galleria mellonella larvae with LC50 concentration to detect the pathogenicity of Galleria mellonella larvae.Spearman test or Pearson test were used to analyze the correlation between the extracellular enzyme activity of Candida glabrata clinical isolates and the pathogenicity of Galleria mellonella larvae. Results: 71 strains of Candida glabrata isolated clinically were detected to have low hemolytic activity after 2 days of culture. Aspartyl protease was detected after 4 days of culture, among which 7 strains (9.86%), 19 strains (26.76%) and 45 strains (63.38%) showed low, medium and high aspartyl protease activity. After 7 days of culture, 71 strains did not detect phospholipase, esterase and lipase activities. Candida glabrata on Galleria mellonella larvae of LC50=2.5×108 CFU/ml Fungal spore were found in the intestinal tissue pathological section of Galleria mellonella larvae in the experimental group, and Candida glabrata was identified by the microbial Mass Spectrometry after culture, while no fungi were found in the pathological section and culture of the control group. Spearman test shows that, there was a linear positive correlation between aspartyl protease activity and the survival rate of Galleria mellonella larvae (r = 0.73, P<0.01), the difference was statistically significant.Pearson test shows that, there was no significant linear relationship between hemolytic activity and survival rate of Galleria mellonella larvae (r = 0.16, P = 0.34), the difference was not statistically significant. Conclusion: The clinical isolates of Candida glabrata in this study had aspartyl protease activity and low hemolytic activity, but no phospholipase, esterase and lipase activity. The activity of aspartyl aspartyl protease of Candida glabrata was positively correlated with the pathogenicity of Galleria mellonella larvae.


Subject(s)
Animals , Sheep , Larva/microbiology , Virulence , Candida glabrata , Agar , Moths/microbiology , Esterases , Aspartic Acid Proteases , Lipase
3.
Chinese Journal of Biotechnology ; (12): 1578-1595, 2023.
Article in Chinese | WPRIM | ID: wpr-981155

ABSTRACT

Flagella are the main motility structure of Clostridioides difficile that affects the adhesion, colonization, and virulence of C. difficile in the human gastrointestinal tract. The FliL protein is a single transmembrane protein bound to the flagellar matrix. This study aimed to investigate the effect of the FliL encoding gene flagellar basal body-associated FliL family protein (fliL) on the phenotype of C. difficile. The fliL gene deletion mutant (ΔfliL) and its corresponding complementary strains (: : fliL) were constructed using allele-coupled exchange (ACE) and the standard molecular clone method. The differences in physiological properties such as growth profile, antibiotic sensitivity, pH resistance, motility, and spore production ability between the mutant and wild-type strains (CD630) were investigated. The ΔfliL mutant and the : : fliL complementary strain were successfully constructed. After comparing the phenotypes of strains CD630, ΔfliL, and : : fliL, the results showed that the growth rate and maximum biomass of ΔfliL mutant decreased than that of CD630. The ΔfliL mutant showed increased sensitivity to amoxicillin, ampicillin, and norfloxacin. Its sensitivity to kanamycin and tetracycline antibiotics decreased, and the antibiotic sensitivity partially returned to the level of CD630 strain in the : : fliL strain. Moreover, the motility was significantly reduced in the ΔfliL mutant. Interestingly, the motility of the : : fliL strain significantly increased even when compared to that of the CD630 strain. Furthermore, the pH tolerance of the ΔfliL mutant significantly increased or decreased at pH 5 or 9, respectively. Finally, the sporulation ability of ΔfliL mutant reduced considerably compared to the CD630 strain and recovered in the : : fliL strain. We conclude that the deletion of the fliL gene significantly reduced the swimming motility of C. difficile, suggesting that the fliL gene is essential for the motility of C. difficile. The fliL gene deletion significantly reduced spore production, cell growth rate, tolerance to different antibiotics, acidity, and alkalinity environments of C. difficile. These physiological characteristics are closely related to the survival advantage in the host intestine, which is correlated with its pathogenicity. Thus, we suggested that the function of the fliL gene is closely related to its motility, colonization, environmental tolerance, and spore production ability, which consequently affects the pathogenicity of C. difficile.


Subject(s)
Humans , Clostridioides/metabolism , Clostridioides difficile/metabolism , Bacterial Proteins/metabolism , Virulence , Anti-Bacterial Agents/metabolism
4.
Chinese Journal of Preventive Medicine ; (12): 929-934, 2023.
Article in Chinese | WPRIM | ID: wpr-985498

ABSTRACT

Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic pathogenic bacterium with complex pathogenesis and drug resistance mechanisms. It has high morbidity and mortality and can cause acute and chronic infections in immunocompromised individuals, with lung infections, wound infections, and bloodstream infections being the most common. The animal infection model of P. aeruginosa is of great value for in-depth research on the pathogenicity, drug resistance, and therapeutic measures of P. aeruginosa by simulating the pathways of human bacterial infections. This article firstly summarizes the selection, anesthesia, and disposal of experimental animals in the construction of animal models of P. aeruginosa infection, and then reviews the methods of construction, model evaluation, and applications of animal models of P. aeruginosa pulmonary infection, wound infection, and bloodstream infection, in order to provide a reference for scientific research related to P. aeruginosa infectious diseases.


Subject(s)
Humans , Animals , Pseudomonas Infections/microbiology , Models, Animal , Virulence , Pseudomonas aeruginosa , Disease Models, Animal
5.
Braz. j. biol ; 83: e248975, 2023. tab, graf
Article in English | LILACS, VETINDEX | ID: biblio-1339377

ABSTRACT

Abstract Colletotrichum is one of the most economically important fungal genera, which affects a wide range of hosts, specifically tropical and subtropical crops. Thus far, there have been several records of mycovirus infection in Colletotrichum spp., primarily by viruses of the Partitiviridae family. There have also been records of infections by mycoviruses of the Chrysoviridae family. Mycoviruses are (+)ssRNA and dsRNA genome viruses, which may or may not be enveloped. To date, no mycovirus with a DNA genome has been isolated from Colletotrichum spp. Typically, mycoviruses cause latent infections, although hypo- and hypervirulence have also been reported in Colletotrichum spp. In addition to its effects on pathogenic behavior, mycovirus infection can lead to important physiological changes, such as altered morphological characteristics, reduced vegetative growth, and suppressed conidia production. Therefore, research on mycoviruses infecting phytopathogenic fungi can help develop alternative methods to chemical control, which can cause irreversible damage to humans and the environment. From an agricultural perspective, mycoviruses can contribute to sustainable agriculture as biological control agents via changes in fungal physiology, ultimately resulting in the total loss of or reduction in the virulence of these pathogens.


Resumo Colletotrichum é um dos gêneros fúngicos mais importantes economicamente, afetando uma ampla gama de hospedeiros, especialmente em cultivos tropicais e subtropicais. Atualmente já existem diversos registros de infecção por micovírus em Colletotrichum spp., sendo a maioria dos já identificados classificados na família Partitiviridae. Ocorrem registros também de micovírus pertencentes à família Chrysoviridae. Compreendem vírus de genoma de (+)ssRNA e dsRNA que podem ser ou não envelopados. Ainda não foram identificados micovírus com genoma de DNA isolados de Colletotrichum. A infecção por micovírus pode ocorrer de forma latente, mas já foi observado em Colletotrichum spp. o fenômeno de hipo e hipervirulência. Além de influenciar no comportamento patogênico, a infecção pode causar mudanças fisiológicas importantes como alterações das características morfológicas, redução do crescimento vegetativo e redução na produção de conídios. O estudo com micovírus em fungos fitopatogênicos traz uma alternativa ao controle químico que é um método capaz de causar danos irreversíveis ao homem e o meio ambiente. Sob a perspectiva agrícola, os micovírus podem contribuir para agricultura sustentável como agentes de controle biológico. Isso porque obsevam-se mudanças importantes na fisiologia fúngica resultando na perda total ou redução da virulência desses patógenos.


Subject(s)
Humans , RNA Viruses , Colletotrichum , Fungal Viruses/genetics , Phylogeny , Spores, Fungal , Virulence
6.
International Journal of Oral Science ; (4): 4-4, 2023.
Article in English | WPRIM | ID: wpr-971592

ABSTRACT

Periodontitis is the most widespread oral disease and is closely related to the oral microbiota. The oral microbiota is adversely affected by some pharmacologic treatments. Systemic antibiotics are widely used for infectious diseases but can lead to gut dysbiosis, causing negative effects on the human body. Whether systemic antibiotic-induced gut dysbiosis can affect the oral microbiota or even periodontitis has not yet been addressed. In this research, mice were exposed to drinking water containing a cocktail of four antibiotics to explore how systemic antibiotics affect microbiota pathogenicity and oral bone loss. The results demonstrated, for the first time, that gut dysbiosis caused by long-term use of antibiotics can disturb the oral microbiota and aggravate periodontitis. Moreover, the expression of cytokines related to Th17 was increased while transcription factors and cytokines related to Treg were decreased in the periodontal tissue. Fecal microbiota transplantation with normal mice feces restored the gut microbiota and barrier, decreased the pathogenicity of the oral microbiota, reversed the Th17/Treg imbalance in periodontal tissue, and alleviated alveolar bone loss. This study highlights the potential adverse effects of long-term systemic antibiotics-induced gut dysbiosis on the oral microbiota and periodontitis. A Th17/Treg imbalance might be related to this relationship. Importantly, these results reveal that the periodontal condition of patients should be assessed regularly when using systemic antibiotics in clinical practice.


Subject(s)
Humans , Mice , Animals , Dysbiosis , Anti-Bacterial Agents/pharmacology , Virulence , Microbiota , Periodontitis/chemically induced , Cytokines
7.
Chinese Journal of Contemporary Pediatrics ; (12): 1-4, 2023.
Article in Chinese | WPRIM | ID: wpr-971031

ABSTRACT

Since the global pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 2020, the virus has been evolving through mutations to acquire enhanced infectivity but reduced virulence. With a wide vaccination coverage among Chinese population, China is entering a new stage of SARS-CoV-2 infection control. The Working Group for the Prevention and Control of Neonatal SARS-CoV-2 Infection in the Perinatal Period of the Editorial Committee of Chinese Journal of Contemporary Pediatrics released the first and second editions of perinatal and neonatal management plan for prevention and control of SARS-CoV-2 infection in January and March 2020, respectively. In order to follow up new prevention and control needs, it is necessary to update the management plan to better guide clinical practice. Therefore, the Working Group formulated the 3rd-edition plan.


Subject(s)
Pregnancy , Infant, Newborn , Female , Humans , Child , COVID-19/epidemiology , SARS-CoV-2 , Pandemics/prevention & control , China/epidemiology , Virulence
8.
Afr. J. Clin. Exp. Microbiol ; 24(2): 1-11, 2023. tables, figures
Article in English | AIM | ID: biblio-1427755

ABSTRACT

Background: Much controversies have been associated with the pathogenicity of Mycoplasma hominis but little has been done to unravel the mystery behind the different views. This study aimed at investigating the genetic variants abounding within M. hominis and the distribution of the virulent genes among the variants. Methodology: Twenty (20) M. hominis isolates from high vaginal swabs of women (11 from pregnant women and 9 from women presenting with infertility) attending the Obstetrics and Gynaecology clinics of Nnamdi Azikiwe University Teaching Hospital (NAUTH), Nnewi, Nigeria, were sequenced using 16S rRNA universal gene target for the purpose of phylogenetic analysis and epidemiological typing. The isolates were also screened for the presence of M. hominis variable adherence antigen (vaa) and p120 virulent genes using primer constructs from the respective genes in a conventional PCR protocol. Results: Of the 20 M. hominis vaginal isolates, 4 phylogenetic strains were detected; strain MHS43 constituted 10/20 (50.0%) [2/9 (22.2%) from infertile women and 8/11 (72.7%) from pregnant women]; strain MHBS constituted 3/20 (15%) [3/9 (33.3%) from infertile women and 0/11 (0%) from pregnant women]; strain MHSWP2 constituted 4/20 (20.0%) [3/9 (33.3%) from infertile women and 1/11 (9.1%) from pregnant women]; while strain MHKC87 constituted 3/20 (15%) [1/9 (11.1%) from infertile women and 2/11 (18.2%) from pregnant women].Each of vaa and p120 genes was detected in 14 of 20 isolates, while 6 isolates did not carry the genes. A 2-way ANOVA test showed that none of the genes was significantly associated with a particular strain (p=0.8641). Conclusions: The different views regarding the pathogenicity of M. hominis may be linked to the heterogeneity within the species and lack of homogeneity in the virulent genes as witnessed both in the intra species and intra strain levels.


Subject(s)
Humans , Mycoplasma hominis , Virulence Factors , Sprains and Strains , Virulence , Population Characteristics , Pregnant Women
9.
ABCS health sci ; 47: e022203, 06 abr. 2022. tab, graf
Article in English | LILACS | ID: biblio-1363538

ABSTRACT

INTRODUCTION: Contamination of cell phones can contribute to the dissemination of pathogens in the community and/or hospital environment. OBJECTIVE: To characterize Staphylococcus aureus strains isolated from cell phones of university students. METHODS: Samples were collected from 100 cell phones. Detection of genes associated with virulence factors such as biofilm formation (icaA and icaD), enterotoxins production (SEA, SEB, SEC, and SED), and resistance to methicillin (mecA and mecC) was performed in S. aureus isolates by PCR. Typing mecA gene performed by multiplex PCR. Susceptibility to antimicrobials and biofilm formation rate also evaluated by using disk diffusion test and crystal violet staining. RESULTS: S. aureus was present in 40% of the total samples and about 70% of them belonged to Nursing students. Of the isolates, 85% presented resistance to penicillin and 50% were classified as moderate biofilm producers. In addition, 92.5% of isolates contained the gene icaA and 60% of the gene icaD. Approximately 25% of the isolates presented the mecA gene. Typing of the mecA gene showed the presence of staphylococcal chromosome cassette SCCmec I and c III respectively in 20% and 10% of the isolates. 70% of the samples could not be typed by the technique. Regarding the enterotoxins, the most prevalent gene was SEA (30%) followed by the SEC gene (2.5%). The presence of SED and SEB genes not observed in any of the isolates. CONCLUSION: The cleaning and periodic disinfection of cell phones can contribute to the reduction of the risk of nosocomial infection.


INTRODUÇÃO: A contaminação de celulares pode contribuir para a disseminação de patógenos na comunidade e/ou ambiente hospitalar. OBJETIVO: Caracterizar cepas de Staphylococcus aureus de telefones celulares de estudantes universitários. MÉTODOS: Foram coletadas amostras de 100 telefones celulares. Detecção de genes associados a fatores de virulência quanto a: formação de biofilme (icaA e icaD), produção de enterotoxinas (SEA, SEB, SEC e SED) e resistência à meticilina (mecA e mecC) foi realizada em isolados de S. aureus por PCR. A Tipagem do gene mecA foi realizada por PCR multiplex. A susceptibilidade a antimicrobianos e a taxa de formação de biofilme pelo teste de difusão em disco e coloração com cristal violeta. RESULTADOS: S. aureus esteve presente em 40% do total de amostras, destas, 70% pertenciam a estudantes do curso de enfermagem. Dos isolados, 85% apresentaram resistência à penicilina e 50% foram classificados com moderada formação de biofilme. Além disso, 92,5% dos isolados continham o gene icaA e 60% o gene icaD. Aproximadamente 25% dos isolados apresentaram o gene mecA. A tipagem do gene mecA mostrou a presença do cassete cromossômico estafilocócico SSCmec I e III em respectivamente 20% e 10% dos isolados. 70% das amostras não puderam ser identificadas pela técnica. Das enterotoxinas, o gene mais prevalente foi o SEA (30%), seguido pelo gene SEC (2.5%). A presença dos genes SED e SEB não foi observada nos isolados. CONCLUSÃO: A limpeza e desinfecção periódica dos telefones celulares podem contribuir para a redução do risco de infecção nosocomiais.


Subject(s)
Students, Health Occupations , Universities , Cell Phone , Methicillin-Resistant Staphylococcus aureus , Virulence , Drug Resistance, Microbial , Biofilms , Enterotoxins
10.
Rev. peru. med. exp. salud publica ; 39(1): 98-103, ene.-mar. 2022. tab, graf
Article in Spanish | LILACS | ID: biblio-1389934

ABSTRACT

RESUMEN Los asilos de ancianos son instituciones con una alta prevalencia de infecciones del tracto urinario ocasionado por Escherichia coli productoras de ß-lactamasas de espectro extendido (BLEE), con diversos factores de virulencia. El objetivo del estudio fue determinar la frecuencia del gen bla CTX-M y de ocho genes de virulencia en 35 E. coli uropatógenas productoras de BLEE provenientes de seis asilos en Perú, durante el 2018. El 57,1% (20/35) de las E. coli fueron portadores del gen bla CTX-M. Además, se obtuvo una frecuencia del 46% (15/35) y 37% (13/35) de hly-alfa y cnf-1, respectivamente; elevada presencia de los genes iucC (63%, 22/35), aer (94%, 33/35) y chuA (94%, 33/34) y una frecuencia del 46% (16/35) y del 91% (32/34) de los genes pap GII y nanA, respectivamente. Existe predominancia en la distribución del gen bla CTX-M, además de una alta frecuencia de exotoxinas que le confieren una ventaja competitiva para diseminarse hacia el torrente sanguíneo.


ABSTRACT Nursing homes are institutions with high prevalence of urinary tract infections caused by ESBL-producing E. coli with several virulence factors. The aim of this study was to determine the frequency of the bla CTX-M gene and eight virulence genes in 35 ESBL-producing uropathogenic E. coli from six nursing homes in Peru during 2018. Of the E. coli samples, 57.1% (20/35) were carriers of the bla CTX-M gene. Furthermore, we obtained frequencies of 46% (15/35) and 37% (13/35) for hly-alpha and cnf-1, respectively; we also found high presence of the iucC (63%, 22/35), aer (94%, 33/35) and chuA genes (94%, 33/34) as well as a frequency of 46% (16/35) and 91% (32/34) for the pap GII and nanA genes, respectively. The bla CTX-M gene is predominant and a high frequency of exotoxins gives it a competitive advantage for spreading into the bloodstream.


Subject(s)
Humans , Male , Female , Aged , Aged, 80 and over , Virulence , Escherichia coli , Uropathogenic Escherichia coli , Anti-Bacterial Agents , Urinary Tract Infections , beta-Lactam Resistance , Virulence Factors , Enterobacteriaceae Infections , Homes for the Aged , Infections
11.
Protein & Cell ; (12): 422-445, 2022.
Article in English | WPRIM | ID: wpr-939868

ABSTRACT

Aging-induced changes in the immune system are associated with a higher incidence of infection and vaccination failure. Lymph nodes, which filter the lymph to identify and fight infections, play a central role in this process. However, careful characterization of the impact of aging on lymph nodes and associated autoimmune diseases is lacking. We combined single-cell RNA sequencing (scRNA-seq) with flow cytometry to delineate the immune cell atlas of cervical draining lymph nodes (CDLNs) of both young and old mice with or without experimental autoimmune uveitis (EAU). We found extensive and complicated changes in the cellular constituents of CDLNs during aging. When confronted with autoimmune challenges, old mice developed milder EAU compared to young mice. Within this EAU process, we highlighted that the pathogenicity of T helper 17 cells (Th17) was dampened, as shown by reduced GM-CSF secretion in old mice. The mitigated secretion of GM-CSF contributed to alleviation of IL-23 secretion by antigen-presenting cells (APCs) and may, in turn, weaken APCs' effects on facilitating the pathogenicity of Th17 cells. Meanwhile, our study further unveiled that aging downregulated GM-CSF secretion through reducing both the transcript and protein levels of IL-23R in Th17 cells from CDLNs. Overall, aging altered immune cell responses, especially through toning down Th17 cells, counteracting EAU challenge in old mice.


Subject(s)
Animals , Mice , Aging , Autoimmune Diseases , Disease Models, Animal , Granulocyte-Macrophage Colony-Stimulating Factor/metabolism , Mice, Inbred C57BL , Th17 Cells/metabolism , Uveitis/pathology , Virulence
12.
China Journal of Chinese Materia Medica ; (24): 2288-2295, 2022.
Article in Chinese | WPRIM | ID: wpr-928106

ABSTRACT

Brown rot is a common disease in the cultivation and production of Gastrodia elata, but its pathogens have not been fully revealed. In this study, the pathogenic fungi were isolated and purified from tubers of 77 G. elata samples with brown rot. Pathogens were identified by the pathogenicity test and morphological and molecular identification. The pathogenicity of each pathogen and its inhibitory effects on Armillaria gallica were compared. The results showed that 119 strains of fungi were isolated from tubers of G. elata infected with brown rot. Among them, the frequency of separation of Ilyonectria fungi was as high as 42.01%. The pathogenicity test showed that the pathogenicity characteristics of six strains of fungi were consistent with the natural symptoms of brown rot in G. elata. The morphological and molecular identification results showed that the six strains belonged to I. cyclaminicola and I. robusta in the Nectriaceae family of Sordariomycetes class, respectively. Both types of fungi could produce pigments, conidia, and chlamycospore, and the growth rate of I. cyclaminicola was significantly higher than that of I. robusta. The comparison of pathogenicity showed that the spots formed by I. cyclaminicola inoculation were significantly larger than those of I. robusta inoculation, suggesting I. cyclaminicola was superior to I. robusta in pathogenicity. The results of confrontation culture showed that I. cyclaminicola and I. robusta could signi-ficantly inhibit the germination and cordage growth of A. gallica. A. gallica also inhibited the growth of pathogens, and I. cyclaminicola was less inhibited as compared with I. robusta. The results of this study revealed for the first time that I. cyclaminicola and I. robusta were the pathogens responsible for G. elata brown rot.


Subject(s)
Fungi , Gastrodia , Plant Tubers , Spores, Fungal , Virulence
13.
Journal of Zhejiang University. Science. B ; (12): 328-338, 2022.
Article in English | WPRIM | ID: wpr-929062

ABSTRACT

The aquatic grass Zizania latifolia grows symbiotically with the fungus Ustilago esculenta producing swollen structures called Jiaobai, widely cultivated in China. A new disease of Z. latifolia was found in Zhejiang Province, China. Initial lesions appeared on the leaf sheaths or sometimes on the leaves near the leaf sheaths. The lesions extended along the axis of the leaf shoots and formed long brown to dark brown streaks from the leaf sheath to the leaf, causing sheath rot and death of entire leaves on young plants. The pathogen was isolated and identified as the bacterium Pantoea ananatis, based on 16S ribosomal RNA (rRNA) gene sequencing, multilocus sequence analysis (atpD (β-subunit of ATP synthase F1), gyrB (DNA gyrase subunit B), infB (translation initiation factor 2), and rpoB (β‍-subunit of RNA polymerase) genes), and pathogenicity tests. Ultrastructural observations using scanning electron microscopy revealed that the bacterial cells colonized the vascular tissues in leaf sheaths, forming biofilms on the inner surface of vessel walls, and extended between vessel elements via the perforated plates. To achieve efficient detection and diagnosis of P. ananatis, species-specific primer pairs were designed and validated by testing closely related and unrelated species and diseased tissues of Z. latifolia. This is the first report of bacterial sheath rot disease of Z. latifolia caused by P. ananatis in China.


Subject(s)
Pantoea/genetics , Plant Diseases/microbiology , Poaceae/microbiology , Virulence
14.
Braz. j. biol ; 82: e250778, 2022. tab, graf
Article in English | LILACS, VETINDEX | ID: biblio-1285589

ABSTRACT

Entomopathogenic fungi (EPF) now a possible safer microbial control measure that could be considered as a substitute for chemical control of insect pests. Three EPF viz., Metarihizium anisopliae, Isaria furnosoroseus and Beauveria bassiana were evaluated for their virulence against the grubs of Khapra beetle, Trogoderma granarium (Everts) under laboratory conditions. The isolates were applied by two methods viz., diet incorporation and an immersion method with 3rd instar 20 grubs of T. granarium for each. The virulence of EPF was determined using percent mortality. Significantly higher mortality was observed in M. anisopliae applied through immersion (98.33%) and diet incorporation (93.33%) methods followed by B. bassiana (90.83 and 85.83%, respectively). The mortality caused by I. furnosoroseus was statistically lower in immersion and diet incorporation methods i.e. 81.67 and 73.33%, respectively. Based on the immersion method, all EPF were studied for multiple conidial concentration i.e., 1×104 , 1×105, 1×106, 1×107 and 1×108 under the same in-vitro conditions. All the isolates were pathogenic to grub of T. granarium at the highest conidial concentration. M. anisopliae was proved the most effective virulent resulting in 98.33% mortality of the pest with LT50 4.61 days at 1 × 108 conidial concentration followed by 90.83 and 81.67 percent mortality with 5.07 and 8.01 days LT50, in the application of B. bassiana and I. furnosoroseus, respectively. M. anisopliae showed higher efficacy and could be considered as promising EPF for the development of myco-insecticides against effective biocontrol of T. granarium.


Os fungos entomopatogênicos (FPE) são agora a possível medida de controle microbiano mais segura, que pode ser considerada um substituto para o controle químico de pragas de insetos. Três EPF viz., Metarihizium anisopliae, Isaria furnosoroseus e Beauveria bassiana foram avaliados quanto à sua virulência contra as larvas do besouro Khapra, Trogoderma granarium (Everts) em condições de laboratório. Os isolados foram aplicados por dois métodos, a saber: incorporação de dieta e um método de imersão com 20 larvas de T. granarium de 3º ínstar para cada um. A virulência do EPF foi determinada usando a mortalidade percentual. Mortalidade significativamente maior foi observada em M. anisopliae aplicado pelos métodos de imersão (98,33%) e incorporação de dieta (93,33%), seguido por B. bassiana (90,83% e 85,83%, respectivamente). A mortalidade causada por I. furnosoroseus foi estatisticamente menor nos métodos de imersão e incorporação de dieta, ou seja, 81,67% e 73,33%, respectivamente. Com base no método de imersão, todos os EPFs foram estudados para múltiplas concentrações de conídios, ou seja, 1 × 104, 1 × 105, 1 × 106, 1 × 107 e 1 × 108 nas mesmas condições in vitro. Todos os isolados foram patogênicos à larva de T. granarium na maior concentração de conídios. M. anisopliae provou ser o virulento mais eficaz, resultando em 98,33% de mortalidade da praga com LT50 4,61 dias na concentração de 1 × 108 conídios seguido por 90,83% e 81,67% de mortalidade com 5,07 e 8,01 dias LT50, na aplicação de B. bassiana e I. furnosoroseus, respectivamente. M. anisopliae apresentou maior eficácia e pode ser considerada como um PFE promissor para o desenvolvimento de micoinseticidas contra o biocontrole efetivo de T. granarium.


Subject(s)
Animals , Oryza , Coleoptera , Beauveria , Virulence , Pest Control, Biological , Larva
15.
São Paulo; s.n; 2022. 104 p.
Thesis in Portuguese | LILACS | ID: biblio-1401032

ABSTRACT

Enterococcus spp. são bactérias caracterizadas como cocos Gram-positivos, frequentemente encontradas na microbiota normal do trato gastrointestinal de seres humanos e animais homeotermos, também sendo encontradas em solos, águas e plantas. Esses micro-organismos são considerados importantes indicadores de contaminação fecal para águas marinhas, e embora sejam descritos como comensais, podem estar associados a uma grande variedade de infecções humanas. A habilidade de adquirirem resistência a antimicrobianos além de sua resistência intrínseca, bem como o contexto de crescimento desfreado de cidades, consumo cada vez maior de antibióticos e poluição das águas, constituem fatores cruciais para que os enterococcus sejam considerados organismos relevantes para a saúde pública global. Dessa forma, o objetivo deste estudo foi caracterizar o perfil fenotípico e genotípico de resistência antimicrobiana e virulência em três espécies de Enterococcus isoladas de águas recreacionais costeiras em praias do estado de São Paulo. Para este projeto foram selecionadas quatro praias do litoral do estado de São Paulo, que são monitoradas pela CETESB como parte do programa de balneabilidade das praias paulistas. As placas contendo colônias de enterococos isoladas em ágar mEI foram levadas para o Laboratório de Microbiologia Ambiental e Resistência Antimicrobiana (MicroRes) da Faculdade de Saúde Pública/USP quinzenalmente de junho de 2019 até março de 2020. A identificação e triagem das espécies de enterococos foi realizada pela técnica de MALDI-TOF MS, e posteriormente os isolados identificados como E. faecium, E. faecalis e E. hirae foram selecionados para confirmação de espécie pela técnica de PCR convencional. Após confirmação foi avaliada a susceptibilidade à antimicrobianos de uso comum. Posteriormente foi realizada a detecção de genes de resistência e virulência nessas três espécies. Em 90,7% dos isolados se observou resistência a pelo menos 1 dos 14 antimicrobianos testados, e em 41,5% se obversou resistência a pelo menos três antimicrobianos de classes diferentes e índice MAR superior a 0,2 sendo, portanto, classificados como multirresistentes (MDR). A maioria dos isolados de enterococos demonstraram resistência a rifampicina (39,2%). Genes que conferem resistência à classe dos macrolídeos (ermB) e às tetraciclinas (tetM e tetL) foram os mais prevalentes entre os isolados, com 14,6% e 12,3% respectivamente. Os isolados da espécie E. faecalis apresentaram positividade a pelo menos 1 dos 5 marcadores de virulência testados. Isolados de E. faecalis apresentaram um perfil de virulência mais diversificado quando comparados aos isolados de E. faecium e E. hirae. A presença de estirpes com múltipla resistência aos antimicrobianos somada a positividade para outros fatores de virulência pode ser indicativa de risco para a saúde pública se essas estirpes chegarem a atingir as áreas de praia utilizadas por banhistas, reforçando a importância de estudos conduzidos em águas recreacionais.


Enterococcus spp. are bacteria characterized as Gram-positive cocci, often found in the normal microbiota of the gastrointestinal tract of humans and homeotherm animals, in soils, water and plants. These microorganisms are considered important indicators of fecal contamination for marine waters, and although they are described as commensals, they can be associated with a wide variety of human infections. The ability to acquire antimicrobial resistance in addition to their intrinsic resistance, as well as the context of uncontrolled growth of cities, increasing consumption of antibiotics and water pollution, are crucial factors for enterococci to be considered relevant organisms for public health. Thus, the aim of this study was to characterize the phenotypic and genotypic profile of antimicrobial resistance and virulence in three Enterococcus species isolated from coastal recreational waters on beaches in the state of São Paulo. For this project, four beaches were selected, which are monitored by CETESB as part of the balneability program. The plates containing colonies of enterococci were taken to the Laboratory of Environmental Microbiology and Antimicrobial Resistance (MicroRes) of the Faculdade de Saúde Pública/USP fortnightly from June 2019 to March 2020. The identification and screening of enterococci species were performed by the MALDI-TOF MS technique, and later the isolates identified as E. faecium, E. faecalis and E. hirae were selected for species confirmation using conventional PCR technique. After confirmation, susceptibility to antimicrobials was evaluated. Subsequently, it was performed the detection of resistance and virulence genes in these three species. In 90.7% of the isolates we observed resistance to at least 1 of the 14 antimicrobials tested, and in 41.5% resistance was observed to at least three antimicrobials of different classes and a MAR index greater than 0.2, therefore, classified as multidrug resistant (MDR). Most enterococci showed resistance to rifampicin (39.2%). Genes that confer resistance to the macrolide (ermB) and to tetracycline (tetM and tetL) were the most prevalent among the isolates, with 14.6% and 12.3% respectively. E. faecalis strains were positive for at least 1 of the 5 virulence markers tested. E. faecalis isolates showed a more diverse virulence profile when compared to E. faecium and E. hirae isolates. The presence of strains with multiple antimicrobial resistance added to positivity for other virulence factors may indicate a risk to public health if these strains reach the beach areas used by bathers, reinforcing the importance of studies conducted in recreational waters.


Subject(s)
Virulence , Drug Resistance, Microbial , Coastal Water , Recreational Water , Enterococcus
16.
São Paulo; s.n; s.n; 2022. 143 p. tab, graf.
Thesis in Portuguese | LILACS | ID: biblio-1416818

ABSTRACT

Leptospira spp. constitui um grupo de bactérias espiroquetas gram-negativas englobando espécies saprofíticas, intermediárias e patogênicas, sendo as últimas agentes causadores da leptospirose, doença zoonótica de alcance mundial e endêmica em regiões tropicais em desenvolvimento. O crescente número de espécies identificadas de leptospiras destaca ainda mais sua diversidade genética e mecanismos de virulência únicos, muitos deles com função ainda desconhecida. Esforços para o desenvolvimento de novas vacinas com proteção cruzada e efeito duradouro revelaram possíveis candidatos vacinais que necessitam ser adequadamente validados, sendo assim, há ainda uma urgente necessidade de uma vacina universal contra a leptospirose capaz de controlar e reduzir os surtos cada vez mais frequentes da doença. Adesinas são importantes fatores de virulência em diversos patógenos, constituindo antígenos promissores para o desenvolvimento de vacinas contra a leptospirose, assim como para o desenvolvimento de métodos diagnósticos mais rápidos e precisos. Previamente, foram identificadas três proteínas hipotéticas conservadas em L. interrogans pela técnica de phage display, denominadas arbitrariamente como LepA069, LepA962 e LepA388. A expressão do gene codificador da proteína LepA069 apresentou aumento de aproximadamente 70 % em animais infectados por leptospiras virulentas, representando a primeira evidência funcional desta proteína ainda desconhecida. Porções recombinantes da lipoproteína hipotética LepA962 (LepA962_Nt e LepA962_Phg) foram obtidos, sendo demonstrada a forte interação da proteína LepA962_Phg, contendo a sequência identificada por phage display, com laminina, fibronectina plasmática, colágeno I e fibrinogênio de maneira dose-dependente. Adicionalmente, LepA962_Phg apresentou ligação às células VERO e à sua matriz extracelular secretada, e o soro obtido a partir desta proteína recombinante foi capaz de se ligar à superfície de leptospiras virulentas, indicando que LepA962_Phg pode representar um importante domínio de interação entre as leptospiras e seu hospedeiro. Finalmente, a proteína LepA388 pertencente a uma extensa família de proteínas modificadoras de virulência com função desconhecida (DUF_61), presente apenas nas leptospiras patogênicas mais virulentas, apresentou aumento na expressão de seu gene codificador em animais infectados por leptospiras virulentas de acordo com dados na literatura. Além disso, porções recombinantes da região Nterminal desta proteína apresentaram ligação a laminina, colágenos I e IV, vitronectina e fibronectinas plasmática e celular, principalmente considerando a sequência identificada por phage display. Estes dados reforçam as predições de modelos tridimensionais da proteína LepA388 e de outros membros da família DUF_61, as quais identificam domínios semelhantes a toxinas (como abrina e CARDS) responsáveis pela ligação e internalização celulares nos hospedeiros. Dados recentes sugerem um possível papel citotóxico desempenhado pelas proteínas desta família em leptospiras, as quais podem também ser consideradas potenciais candidatas vacinais e para diagnóstico da leptospirose, devido à sua distribuição restrita em espécies e cepas patogênicas de importância para saúde humana.


Leptospira spp. constitutes a group of gram-negative spirochete bacteria comprising saprophytic, intermediate and pathogenic species, the last being causative agents of leptospirosis, a zoonotic disease of worldwide extent and endemic in developing tropical regions. The growing number of identified leptospiral species further highlights their genetic diversity and unique virulence mechanisms, many of them with unknown function. Efforts to develop new vaccines with cross-protection and long-lasting effect have revealed possible vaccine candidates that need to be properly validated. Therefore, there is still an urgent need for a universal vaccine against leptospirosis capable of controlling and reducing the increasing outbreaks of the disease. Adhesins are important virulence factors in several pathogens, constituting promising antigens for the development of vaccines against leptospirosis, as well as for the development of faster and more accurate diagnostic methods. Previously, three conserved hypothetical proteins in L. interrogans were identified by phage display technique, arbitrarily named as LepA069, LepA962 and LepA388. Expression of the LepA069 encoding gene showed an increase of approximately 70 % in animals infected by virulent leptospires, representing the first functional evidence of this still unknown protein. Recombinant portions of the hypothetical lipoprotein LepA962 (LepA962_Nt and LepA962_Phg) were obtained, demonstrating the strong interaction of the LepA962_Phg protein, containing the sequence identified by phage display, with laminin, plasma fibronectin, collagen I and fibrinogen in a dose-dependent manner. Furthermore, LepA962_Phg showed binding to VERO cells and its secreted extracellular matrix, and the serum obtained from this recombinant protein was able to bind to the surface of virulent leptospires, indicating that LepA962_Phg may represent an important domain of interaction between leptospires and its host. Finally, LepA388 protein belonging to an extensive family of virulence modifying proteins with unknown function (DUF_61), present only in the most virulent pathogenic leptospires, showed an increase in the expression of its encoding gene in animals infected by virulent leptospires according to data in literature. Moreover, recombinant portions of the N-terminal region of this protein showed binding to laminin, collagens I and IV, vitronectin and plasma and cell fibronectins, especially considering the sequence identified by phage display. These data support the predictions of three-dimensional models of the LepA388 protein and other members of the DUF_61 family, which identify toxin-like domains (such as abrin and CARDS) responsible for cellular binding and internalization in hosts. Recent data suggest a possible cytotoxic role played by proteins of this family in leptospires, which can also be considered potential vaccine candidates and antigens for diagnosis, due to their restricted distribution in pathogenic species and strains of importance to human health


Subject(s)
Adhesins, Bacterial/classification , Virulence Factors/adverse effects , Vaccine Development/instrumentation , Leptospira interrogans/metabolism , Virulence , Vaccines/analysis , Dosage , Cell Surface Display Techniques , Leptospirosis/pathology
17.
Rev. peru. med. exp. salud publica ; 38(4): 615-620, oct.-dic. 2021. tab, graf
Article in Spanish | LILACS | ID: biblio-1365919

ABSTRACT

RESUMEN El objetivo del estudio fue identificar molecularmente los genes de virulencia y resistencia a macrólidos en aislamientos clínicos de Streptococcus agalactiae (EGB), recuperados en 2019 a partir de secreción vaginal (n=9) y orina (n=22), en dos establecimientos de salud de Lima. La identificación y susceptibilidad antimicrobiana se determinaron por el sistema automatizado Vitek® 2, se confirmó la identificación fenotípicamente; la resistencia a macrólidos por el método D-test; la identificación de genes de virulencia (lmb, bca y rib) y de resistencia a macrólidos (ermB, ermTR y mefA) por reacción en cadena de la polimerasa (PCR). El fenotipo y genotipo de resistencia a macrólidos predominante fue cMLSb (12/31) y ermB (11/31), y el gen de virulencia más frecuente fue lmb (23/31). Todos fueron sensibles a penicilina, ampicilina y vancomicina. Estos hallazgos muestran la necesidad de implementar estudios de epidemiología molecular que permitan un adecuado conocimiento y seguimiento de EGB en el Perú.


ABSTRACT The aim of the study was to molecularly identify virulence and macrolide resistance genes in clinical isolates of Streptococcus agalactiae (GBS), recovered in 2019 from vaginal discharge (n=9) and urine (n=22), from two health facilities in Lima. Identification and antimicrobial susceptibility were determined by the Vitek® 2 automated system, identification was confirmed phenotypically; macrolide resistance was determined by the D-test method. Identification of virulence genes (lmb, bca and rib) and macrolide resistance genes (ermB, ermTR and mefA) was carried out by polymerase chain reaction (PCR). The predominant macrolide resistance phenotype and genotype were cMLSb (12/31) and ermB (11/31); the most frequent virulence gene was lmb (23/31). All were sensitive to penicillin, ampicillin and vancomycin. These findings show the need to implement molecular epidemiology studies that allow adequate knowledge and follow-up of GBS in Peru.


Subject(s)
Streptococcus agalactiae , Virulence , Drug Resistance , Microbial Sensitivity Tests , Penicillins , Polymerase Chain Reaction , Macrolides , Genes
18.
Bol. micol. (Valparaiso En linea) ; 36(2): 14-19, dic. 2021.
Article in Spanish | LILACS | ID: biblio-1352557

ABSTRACT

Ha surgido una nueva variante de preocupación de SARS-CoV-2, cuyos efectos en la evolución de la pandemia parecen inciertos. Sin embargo, ha comenzado a surgir evidencia con respecto al comportamiento viral en cuanto a su transmisibilidad, unión a receptor de la célula hospedadora y escape del sistema inmune. Presentamos una revisión actualizada de los datos existentes en la literatura respecto a los aspectos microbiológicos y epidemiológicos que pueden ayudarnos a comprender las futuras investigaciones en esta variante.(AU)


A new variant of concern for SARS-CoV-2 has emerged, the effects of which on the evolution of the pandemic appear uncertain. However, evidence has begun to emerge regarding viral behavior in terms of its transmissibility, receptor binding on the host cell, and escape from the immune system. We present an updated review of the existing data in the literature regarding the microbiological and epidemiological aspects that can help us understand future research on this variant.(AU)


Subject(s)
Evolution, Molecular , SARS-CoV-2/genetics , Virulence , Behavior , SARS-CoV-2/pathogenicity , COVID-19/epidemiology
19.
Rev. psicanal ; 28(1): 103-120, Abril 2021.
Article in Portuguese | LILACS, INDEXPSI | ID: biblio-1252999

ABSTRACT

O presente trabalho parte da ideia de caracterizar o disruptivo no pensamento freudiano. Como ponto de partida, toma o trabalho de 1914, À guisa de introdução ao narcisismo, por reconhecer nele um momento primeiro de ruptura na teoria pulsional vigente: libido do Eu versus libido objetal. Durante o trajeto, sinaliza marcas desse processo e direciona-se para o disruptivo que se instala em termos metapsicológicos, com maior consistência, com o advento da pulsão de morte. A pulsão de destruição, como agente do disruptivo em sua relação com Eros, desenhará caminhos que permitem vislumbrar destinos tanáticos ou criativos. Com essa concepção metapsicológica como indicador, busca-se refletir a respeito da interação entre o disruptivo da pandemia viral e o disruptivo da virulência do racismo e seus desdobramentos criativos na efetivação, pelo coletivo da humanidade, de posturas antirracistas. Tal contexto alberga uma interrogação pontual: como a pandemia, em seu efeito disruptivo, está relacionada com a percepção em toda a sua sensorialidade, em grande escala, de norte a sul, daquilo que mantinha-se parcialmente silencioso e invisível, o racismo? (AU)


The present article begins from the idea of characterize the disruptive in the freudian's thoughts. Is takes as a starter point the work of 1914, On narcissism: an introduction, for recognize it as a first moment of rupture in the current drive theory: self libido versus object libido. In this path, it signals marks of this process and orientate to the disruptive that develops in metapsychological terms, with great consistency, with the advent of the death drive. The destruction drive, as a disruptive agent, in its relation with Eros, will draw paths that allow glimpse its tanatic fate or criative fate. From this metapsychological conception, as an indicator, seeks to reflect the interaction between the disruptive in the viral pandemic and the disruptive in the racism virulence, and its criatives developments in the effectuation of anti-racist postures, by the humanity collective. Context that holds an punctual interrogation: how the pandemic, with its disruptive effect, is related with the perception in all its sensoriality, in big scale, from north to south, with what was, in part, silence and inivisible: the racism? (AU)


El objetivo inicial del presente trabajo es caracterizar lo disruptivo en el pensamiento freudiano. Se toma como punto de partida el célebre texto de 1914 Introducción del narcisismo por reconocer en él un primer momento de ruptura en la teoría pulsional vigente hasta ese momento, que distinguía la libido del Yo y la libido de objeto. En ese recorrido, se irán señalando marcas de dicho proceso orientándose hacia lo disruptivo, que se instalará con mayor consistencia, en términos metapsicológicos, con el advenimiento de la pulsión de muerte. La pulsión de destrucción, como agente de lo disruptivo, en su relación con Eros, trazará caminos que permiten vislumbrar sus destinos tanáticos o creativos. Tomando esa concepción metapsicológica como indicador, busco reflejar la interacción entre lo disruptivo de la pandemia viral y lo disruptivo de la virulencia del racismo, así como sus desdoblamientos creativos en la adopción de posturas antirracistas por parte del colectivo humano. En este contexto se plantea una interrogación puntual: ¿cómo la pandemia, con su efecto disruptivo, está relacionada con la percepción en toda su sensorialidad, en gran escala, de norte a sur, de aquello que, en parte, se mantenía silencioso e invisible, el racismo?


Subject(s)
Pandemics/prevention & control , Racism/psychology , Rupture/psychology , Virulence , Drive , Narcissism
SELECTION OF CITATIONS
SEARCH DETAIL