RESUMO
Blastic plasmacytoid dendritic-cell neoplasm (BPDCN) is an extremely rare disease that originates from dendritic cells, characterized by co-expression of CD4 and CD56 without any other lineage-specific markers. It is associated with a poor prognosis. Previously, it was referred to by several names, including blastic NK-cell lymphoma, agranular CD4+ natural killer cell leukemia, and agranular CD4+CD56+ hematodermic neoplasm. The various nomenclatures and its evolution reflect the uncertainty of its histogenesis and the challenges involved in describing this hematopoietic neoplasm. Diagnosis challenge is due to similarities with CD4+CD56+ acute myeloid leukemia (AML) and histiocytic sarcoma (HS) immunophenotypic and histopathological features. We report a case of a 42-year-old male who presented with skin lesions and pancytopenia. While biologists suspected the diagnosis of BPDCN or CD4+ CD56+ AML based on the flow cytometry (FCM), anatomic pathologists retained the diagnosis of HS. The patient didn't respond to a systemic combination chemotherapy regimen and passed away rapidly. BPDCN diagnosis requires careful and exhaustive analyses in order to formulate the most appropriate therapeutic plan and to improve its prognosis.
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Antígenos CD4 , Antígeno CD56 , Células Dendríticas , Leucemia Mieloide Aguda , Humanos , Masculino , Antígeno CD56/análise , Adulto , Leucemia Mieloide Aguda/diagnóstico , Leucemia Mieloide Aguda/patologia , Células Dendríticas/patologia , Antígenos CD4/análise , Neoplasias Hematológicas/patologia , Neoplasias Hematológicas/diagnóstico , Diagnóstico Diferencial , Evolução Fatal , Neoplasias Cutâneas/diagnóstico , Neoplasias Cutâneas/patologia , ImunofenotipagemRESUMO
Cure rates for acute myeloid leukemia (AML) remain suboptimal; thus, new treatment strategies are needed for this deadly disease. Artemisia campestris leaves hold significant value in traditional medicine. Despite extensive research conducted on this plant globally, the specific anti-AML properties of the leaves have received limited investigation. This study aims to explore the potential anti-leukemic activities of the ethyl acetate extract derived from Artemisia campestris (EAEAC), using mononuclear cells from bone marrow of thirteen AML patients. To this end, cytotoxic effects were evaluated using the MTT assay, and the mechanisms of cell death were investigated through various methods, including propidium iodide staining, annexin V/propidium iodide double staining, mitochondrial depolarization, and caspase-3/7 activation assays. Results demonstrated that EAEAC induced cell apoptosis by increasing DNA fragmentation, causing mitochondrial depolarization, and activating caspases 3/7. On the other hand, we assessed EAEAC's effect on two leukemia stem cell subpopulations, with results suggesting a potential decrease in their frequencies (three/five patients).
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Apoptose , Artemisia , Leucemia Mieloide Aguda , Extratos Vegetais , Humanos , Artemisia/química , Extratos Vegetais/farmacologia , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/patologia , Apoptose/efeitos dos fármacos , Feminino , Adulto , Masculino , Pessoa de Meia-Idade , Caspase 3/metabolismo , Antineoplásicos Fitogênicos/farmacologia , Folhas de Planta/químicaRESUMO
Meningeal infiltration in children with B acute lymphoblastic leukemia is one of the most serious complications. Timely diagnosis not only significantly enhances treatment efficacy but also leads to improve patient outcome and reduce risk of relapse. This is particularly crucial in low to middle income countries facing health constraints, where optimizing resources is essential. Conventional cytology (CC) study of cerebrospinal fluid (CSF) is considered in different countries to be the Gold-standard despite its low sensitivity (< 50%). The study of CSF by multiparametric flow cytometry (MFC) appears to be an alternative. The aim of our study was to assess MFC analytical performance compared with CC. Our cross sectional study was conducted over a six-month period in the biological hematology department. CSF samples underwent analysis for the presence of blasts using both CC and MFC. Cytological slides of the CSF were prepared by cytocentrifugation in a Shandon Cytospin 4™. Flow cytometric analysis was performed on the BD FACSLyric™ flow cytometer. All statistical analyses were performed using SPSS version 21.0 (SPSS Inc.). Agreement between the two methods was made using the Kappa index and χ2 test. This study was approved by the local ethics committee. Sixty CSF samples from 39 children with B acute lymphoblastic leukemia were analyzed. Meningeal infiltration was detected respectively in 20% of cases by MFC and 5% of cases by CC, with a significant difference p = 0.006. Comparing the two methods, the Kappa coefficient was 0.35, indicating weak agreement between the two methods. Moreover, MFC positivity was higher even for hypocellular samples. Of the 51 hypocellular samples, eight were positive by MFC while they were negative by CC. MFC shows better sensitivity while retaining good specificity for the detection of meningeal involvement. MFC could therefore be a complementary method to CC for detecting blast cells in the central nervous system.
Assuntos
Citometria de Fluxo , Leucemia-Linfoma Linfoblástico de Células Precursoras B , Humanos , Citometria de Fluxo/métodos , Criança , Masculino , Feminino , Pré-Escolar , Estudos Transversais , Adolescente , Leucemia-Linfoma Linfoblástico de Células Precursoras B/patologia , Leucemia-Linfoma Linfoblástico de Células Precursoras B/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras B/líquido cefalorraquidiano , Lactente , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras/líquido cefalorraquidianoRESUMO
The aim of this study was to evaluate the activated partial thromboplastin time (APTT) and prothrombin time (PT)-based clot waveform analysis (CWA) in patients diagnosed with acute promyelocytic leukemia (APL). APTT-based and PT-based CWA parameters of patients diagnosed with APL were analyzed and compared with healthy volunteers. Four APTT-CWA parameters were noted, maximum velocity corresponding to the first peak of the first derivative (max1), maximum acceleration corresponding to the first peak of the second derivative (max2) and the corresponding peak times of max1 and max2 (Tmax1, Tmax2). For the PT-CWA, two PT-CWA parameters were noted, maximum velocity (max1') and the corresponding timing (Tmax1'). The results were expressed in medians. Mann-Whitney U test was used to compare the CWA parameters. Correlations were examined using the Spearman correlation test. Tmax1 and Tmax2 were significantly prolonged in patients with APL in comparison with healthy volunteers. Although max1 and max2 were lower in APL patients compared with healthy volunteers, no significant difference was noted. There was a strong and significant correlation between the DIC score and the parameters max1, max2 and max1' and a very strong and significant correlation between fibrinogen levels and max1, max2 and max1'. When comparing DIC patients with hypofibrinogenemia and DIC without hypofibrinogenemia, a significant difference was noted in max1, max2, Tmax1 and Tmax2. The APTT and PT-based CWA analysis is a good tool to evaluate the bleeding tendency in APL, as it offers a novel approach for evaluating global hemostasis, predicting the bleeding risk and delivering improvements to APL patients management.
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Afibrinogenemia , Leucemia Promielocítica Aguda , Trombose , Humanos , Testes de Coagulação Sanguínea/métodos , Tempo de Protrombina , Tempo de Tromboplastina ParcialRESUMO
INTRODUCTION: Factor XI deficiency is a rare coagulation disorder with variable bleeding manifestations. AIM: To evaluate the correlation between the degree of factorXI deficiency and the clinical expression of the disease. METHODS: Retrospective study, spanning 10 years from January 1, 2010 to December 31, 2019, concerning patients followed at the Hemophilia Center at Aziza Othmana Hospital in Tunis. The data were collected from the medical records. The determination of PT, APTT, fibrinogen level and coagulation factors are performed by coagulometric technique on STA® compact / ACL TOP®. FactorXI deficiency was confirmed on two different samples. Statistical analysis of the clinical-biological correlation was performed using the chi-square test. The significance level was 0.05. RESULTS: Twenty patients were collected. The mean age of discovery was 25 years with a sex ratio (M/F) =0.33. The circumstances of discovery were incidental in 14 patients. A family history of bleeding was reported in 30% of cases. Eight patients underwent surgery, six of whom had a simple postoperative course. The APTT was prolonged and isolated in 75% of cases. The hemostasis test was normal in 5 cases. The average FactorXI level was 24%. The tendency to bleed did not seem to be correlated with FactorXI levels. CONCLUSION: Prospective multicenter studies including molecular study would be necessary to better elucidate this rare disorder.
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Deficiência do Fator XI , Adulto , Deficiência do Fator XI/complicações , Deficiência do Fator XI/diagnóstico , Deficiência do Fator XI/epidemiologia , Hemorragia , Humanos , Prontuários Médicos , Estudos Prospectivos , Estudos RetrospectivosRESUMO
Even though there is a pressing interest in clean energy sources, compression ignition (CI) engines, also called diesel engines, will remain of great importance for transportation sectors as well as for power generation in stationary applications in the foreseeable future. In order to promote applications dealing with complex diesel alternative fuels by facilitating their integration in numerical simulation, this paper targets three objectives. First, generate novel diesel fuel surrogates with more than one component. Here, five surrogates are generated using an advanced chemistry solver and are compared against three mechanisms from the literature. Second, validate the suggested reaction mechanisms (RMs) with experimental data. For this purpose, an engine configuration, which features a reacting spray flow evolving in a direct-injection (DI), single-cylinder, and four-stroke motor, is used. The RNG k-Epsilon coupled to power-law combustion models is applied to describe the complex in-cylinder turbulent reacting flow, while the hybrid Eulerian-Lagrangian Kelvin Helmholtz-Rayleigh Taylor (KH-RT) spray model is employed to capture the spray breakup. Third, highlight the impact of these surrogate fuels on the combustion properties along with the exergy of the engine. The results include distribution of temperature, pressure, heat release rate (HRR), vapor penetration length, and exergy efficiency. The effect of the surrogates on pollutant formation (NOX, CO, CO2) is also highlighted. The fifth surrogate showed 47% exergy efficiency. The fourth surrogate agreed well with the maximum experimental pressure, which equaled 85 Mpa. The first, second, and third surrogates registered 400, 316, and 276 g/kg fuel, respectively, of the total CO mass fraction at the outlet. These quantities were relatively higher compared to the fourth and fifth RMs.
RESUMO
Factor VII (FVII) deficiency is the most common among all rare inherited bleeding disorders. However, acquired FVII deficiency (aFVIID) is uncommon. Only few cases in the literature have been reported. Herein, we present a case of an aFVIID associated with acute myeloid leukemia (AML), along with a literature review regarding this condition. A 50 year old Arab male patient was diagnosed with AML at the hematology department of our institution. At admission, coagulation tests showed a prolonged prothrombin time (PT) with a normal activated partial thromboplastin time (aPTT) and a slightly elevated fibrinogen level. Prothrombin complex coagulation factors dosing (PCCFD) revealed a decrease only in FVII levels. The patient, however, did not experience any bleeding. The evolution of the health of the patient was marked by a normalization of PT and FVII levels and complete remission.
Assuntos
Deficiência do Fator VII , Leucemia Mieloide Aguda , Fatores de Coagulação Sanguínea , Testes de Coagulação Sanguínea , Fator VII , Deficiência do Fator VII/complicações , Deficiência do Fator VII/diagnóstico , Humanos , Leucemia Mieloide Aguda/complicações , Leucemia Mieloide Aguda/diagnóstico , Masculino , Pessoa de Meia-IdadeRESUMO
Flow cytometry is the gold standard for the detection of paroxysmal nocturnal hemoglobinuria (PNH) clones. Several antibody panels have been used with varying sensitivities and specificities. The CD157 is one of the glycosylphosphatidylinositol-anchored molecules tested and widely used. The CD157 deficiency is rare. We report a case of an isolated CD157 deficiency discovered during the search for the PNH clone in a patient with a plastic anemia. The interpretation of the results in this case poses a problem of false positive. We discuss how to deal with these difficulties encountered by the biologist, detailing the various possible causes. This observation also underlines the importance of following international guidelines before making the diagnosis of the PNH clone which has significant implications.
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Hemoglobinúria Paroxística , Células Clonais , Citometria de Fluxo , Hemoglobinúria Paroxística/diagnóstico , Humanos , Sensibilidade e EspecificidadeRESUMO
Accumulating evidence supports that the viral-induced hyper-inflammatory immune response plays a central role in COVID-19 pathogenesis. It might be involved in the progression to acute respiratory distress syndrome (ARDS), multi-organ failure leading to death. In this study, we aimed to evaluate the prognostic value of the immune-inflammatory biomarkers in COVID-19, then determine optimal thresholds for assessing severe and fatal forms of this disease.153 patients with confirmed COVID-19 were included in this study, and classified into non-severe and severe groups. Plasmatic levels of interleukin 6 (IL6), C-reactive protein (CRP), soluble-IL2 receptor (IL2Rα), procalcitonin (PCT) and ferritin were measured using chemiluminescence assay. Complete blood count was performed by Convergys 3X® hematology analyzer. Our results demonstrated that the peripheral blood levels of IL6, PCT, CRP, ferritin, IL2Rα, white blood cell count (WBC), neutrophil count (NEU), neutrophil-to-lymphocyte ratio (NLR), derived neutrophil-to-lymphocyte ratio (d-NLR) were significantly higher in severe forms of COVID-19. The ROC curve analysis showed that IL6 was the most accurate inflammatory biomarker. The calculated cutoff of IL6 (42 pg/ml) could correctly classify > 90% of patients regarding their risk of severity (area under ROC curve (AUROC) = 0.972) and the threshold value of 83 pg/ml was highly predictive of the progression to death (AUROC = 0.94, OR = 184) after a median of 3 days. Besides, IL-6 was positively correlated with other inflammatory markers and the kinetic analysis highlighted its value for monitoring COVID-19 patients. PCT and NLR had also a high prognostic relevance to assess severe forms of COVID-19 with corresponding AUROC of 0.856, 0.831 respectively. Furthermore the cut-off values of PCT (0.16 ng/ml) and NLR (7.4) allowed to predict mortality with high accuracy (se = 96.3%, sp = 70.5%,OR = 61.2)' (se = 75%, sp = 84%, OR = 14.6).The levels of these parameters were not influenced by corticosteroid treatment, which make them potential prognostic markers when patients are already undergoing steroid therapy.
Assuntos
COVID-19/imunologia , Interleucina-6/sangue , Pandemias , Pró-Calcitonina/sangue , SARS-CoV-2 , Adolescente , Corticosteroides/uso terapêutico , Adulto , Idoso , Idoso de 80 Anos ou mais , Argélia/epidemiologia , Biomarcadores/sangue , Proteína C-Reativa/metabolismo , COVID-19/epidemiologia , COVID-19/mortalidade , Feminino , Ferritinas/sangue , Humanos , Mediadores da Inflamação/sangue , Subunidade alfa de Receptor de Interleucina-2/sangue , Contagem de Linfócitos , Masculino , Pessoa de Meia-Idade , Neutrófilos/imunologia , Valor Preditivo dos Testes , Prognóstico , Estudos Prospectivos , Índice de Gravidade de Doença , Adulto Jovem , Tratamento Farmacológico da COVID-19RESUMO
Factor V deficiency is a rare hemostatic disorder. It may present with a diverse spectrum of symptoms due to a variety of mechanisms including development of autoantibodies associated with a number of conditions. We report a first case of factor V deficiency in Tunisian hemodialysis patient due to an autoantibody most likely secondary to antibiotic exposure responsible for an arteriovenous shunt thrombosis rather than bleeding. We discuss here the clinical and biological features of acquired factor V inhibitor and provide a short review of the current literature.
Assuntos
Derivação Arteriovenosa Cirúrgica/efeitos adversos , Autoanticorpos/sangue , Transtornos da Coagulação Sanguínea/etiologia , Fator V/imunologia , Diálise Renal , Trombose/etiologia , Idoso , Transtornos da Coagulação Sanguínea/sangue , Transtornos da Coagulação Sanguínea/diagnóstico , Fator V/antagonistas & inibidores , Humanos , Masculino , Complicações Pós-Operatórias/sangue , Complicações Pós-Operatórias/diagnóstico , Insuficiência Renal Crônica/sangue , Insuficiência Renal Crônica/complicações , Insuficiência Renal Crônica/terapia , Trombose/sangue , Trombose/diagnóstico , TunísiaRESUMO
BACKGROUND: Von Willebrand's disease (VWD) is the most commonly inherited bleeding disorder. It is characterized by clinical, biological and molecular heterogeneity. In certain types of the disease, diagnosis can be difficult. AIM: We report the clinico-biological characteristics of VWD's patients and analyze diagnosis difficulties. METHODS: 33 cases were diagnosed in the laboratoryfrom February to May, 2011. Screening hemostasis included the measuring of FVIII: C, VWF: Ag and VWF: RCo. Blood cell count and blood group were performed in all cases. RESULTS: Mean age at diagnosis is 13 years [10 months -43 years]. The sex ratio M/F is 0.5. The patients are classified type 3 VWD in 52% of the cases, type 2 VWD in 30 % of the cases and type 1 VWD in 18 % of the cases. The diagnosis of type 2B VWD suspected in combination of the ratio VWF:RCo / VWF: Ag <0,7 and thrombocytopenia in one case. Required tests for positive diagnosis and distinction between the primary categories of VWD are available. Specialized tests will allow a best characterization variants type 2 VWD for a better therapeutic approach.
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Immunophenotyping is a major tool for the diagnosis of the chronic lymphoïd leukaemia (CLL). Its interest remains limited in the classification of the other B chronic lymphoproliférative syndromes (B-CLPS). We evaluate the place of the flow cytometry (CMF) in the diagnosis and classification of the non CLL B-CLPS. The cases with Matutes score of 4 or more are excluded. A confrontation of the results to the histology is made. 28 cases of non CLL B-CLPS are diagnosed. CMF shows a κ monoclonal population in 15 cases and λ in 13 cases. A co-expression CD19+CD5 + is found in 11 cases concording with an atypic CLL or a mantel cell lymphoma in 6 cases with Matutes score of 3. In 5 cases, we concluded to non CLL B-CLPS (Matutes<3). The histology retained the diagnosis of a mantel cell lymphoma (4 cases), a SLVL (1 case) and an atypical LLC (1 case). CD5 is negative in 17 cases. In 5 cases, the diagnosis of hairy cell leukemia (HCL) is retained (CD 11c+ CD103+) and confirmed by the histology. The diagnosis of a marginal zone lymphoma is retained in 2 cases, a SLVL in 2 cases, a follicular lymphoma in 3 cases and prolymphocytes leukaemia in 1 case. Nine cases of non CLL B-CLPS were difficult to classify by histology. CMF is insufficient for the classification of most of the non CLL B-CLPS. Only the phenotype of the HCL is characteristic. The confrontation of the histology results remains essential.
Assuntos
Linfócitos B/patologia , Citometria de Fluxo/métodos , Imunofenotipagem/métodos , Leucemia Linfocítica Crônica de Células B/diagnóstico , Transtornos Linfoproliferativos/diagnóstico , Adulto , Idoso , Idoso de 80 Anos ou mais , Linfócitos B/imunologia , Doença Crônica , Citodiagnóstico/métodos , Diagnóstico Diferencial , Feminino , Humanos , Leucemia Linfocítica Crônica de Células B/epidemiologia , Leucemia Linfocítica Crônica de Células B/imunologia , Transtornos Linfoproliferativos/epidemiologia , Transtornos Linfoproliferativos/imunologia , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , SíndromeRESUMO
BACKGROUND: Immunophenotyping is an essential step in the diagnosis of acute myeloid leukemia. Its prognostic value remains controversial with contradictory results. AIM: To assess prognostic impact of the immunophenotyping in AML. METHODS: Our study is retrospective (October, 2005 - July, 2007) concerning 56 cases of AML (AML3 excluded) of the adult from 18 to 55 years old diagnosed and treated in Tunis Aziza Othmana Hospital. The immunophenotyping was performed by flow cytometry (Beckman Coulter EPICS XL MCL®). We studied clinical and biological characteristic, immunophenotypic expressions, and parameters of the response to the treatment: complete remission (CR), overall survival (OS), relapse free survival (RFS) and relapse in a delay of 1 year and 2 years. SPSS software was used to perform the statistical analysis. RESULTS: The median age of the patients is of 37,7±11.8 years. Sex ratio (M/F) is 1.33. Among individual antigenic expressions, only CD7 is associated to lower CR rates (p=0.044). We did not find any statistically significant association between immunophenotypic expressions and OS nor with relapse or RFS. CONCLUSION: The impact of immunophenotyping in AML remains controversial because of contradictory results. The research of molecular changes would be an interesting alternative in our context.
Assuntos
Imunofenotipagem , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/imunologia , Adolescente , Adulto , Feminino , Humanos , Leucemia Mieloide Aguda/mortalidade , Leucemia Mieloide Aguda/terapia , Masculino , Pessoa de Meia-Idade , Prognóstico , Indução de Remissão , Estudos Retrospectivos , Taxa de Sobrevida , Adulto JovemRESUMO
Inherited factor VII (FVII) deficiency is a rare disorder characterized by a bleeding phenotype varying from mild to severe. To date, more than 200 mutations have been described along the F7 gene encoding for FVII. The aim of this study was the identification of genetic defects underlying FVII deficiency in 10 patients belonging to eight unrelated families of the North provinces from Tunisia. Mutation detection was performed by sequencing the whole F7 gene coding region, exon-intron boundaries and about 400 bp of the promoter region. We identified 5 mutations in five unrelated families; the novel p.F328Y mutation and the reported mutations: p.R304Q, p.M298I, IVS1aG > A and p.G-39G. For the remaining 5 patients we didn't identified any mutations using PCR/Sequencing protocol. In conclusion, this study represents the first comprehensive molecular series of FVII deficiency affected patients in Tunisia from the North. We will try in the future to continue the molecular study for Tunisian patients from Center and South provinces in order to have a complete idea about the FVII deficiency mutational profile in our country. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1288044089753085.
Assuntos
Coagulação Sanguínea/genética , Deficiência do Fator VII/genética , Fator VII/genética , Mutação , Polimorfismo de Nucleotídeo Único , Adolescente , Adulto , Coagulação Sanguínea/efeitos dos fármacos , Fatores de Coagulação Sanguínea/uso terapêutico , Coagulantes/uso terapêutico , Contusões/sangue , Contusões/genética , Análise Mutacional de DNA , Epistaxe/sangue , Epistaxe/genética , Éxons , Deficiência do Fator VII/sangue , Deficiência do Fator VII/tratamento farmacológico , Deficiência do Fator VII/epidemiologia , Feminino , Predisposição Genética para Doença , Humanos , Íntrons , Masculino , Menorragia/sangue , Menorragia/genética , Metrorragia/sangue , Metrorragia/genética , Pessoa de Meia-Idade , Fenótipo , Regiões Promotoras Genéticas , Tunísia/epidemiologia , Adulto JovemRESUMO
The marine bacterium Vibrio tapetis is the causative agent of the brown ring disease, which affects the clam Ruditapes philippinarum and causes heavy economic losses in North of Europe and in Eastern Asia. Further characterization of V. tapetis isolates showed that all the investigated strains harbored at least one large plasmid. We determined the sequence of the 82,266 bp plasmid pVT1 from the CECT4600(T) reference strain and analyzed its genetic content. pVT1 is a mosaic plasmid closely related to several conjugative plasmids isolated from Vibrio vulnificus strains and was shown to be itself conjugative in Vibrios. In addition, it contains DNA regions that have similarity with several other plasmids from marine bacteria (Vibrio sp., Shewanella sp., Listonella anguillarum and Photobacterium profundum). pVT1 contains a number of mobile elements, including twelve Insertion Sequences or inactivated IS genes and an RS1 phage element related to the CTXphi phage of V. cholerae. The genetic organization of pVT1 underscores an important role of horizontal gene transfer through conjugative plasmid shuffling and transposition events in the acquisition of new genetic resources and in generating the pVT1 modular organization. In addition, pVT1 presents a copy number of 9, relatively high for a conjugative plasmid, and appears to belong to a new type of replicon, which may be specific to Vibrionaceae and Shewanelleacae.
Assuntos
Bivalves/microbiologia , Conjugação Genética/genética , Transferência Genética Horizontal/fisiologia , Plasmídeos/genética , Vibrio/genética , Animais , Sequência de Bases , Clonagem Molecular , Dosagem de Genes , Modelos Genéticos , Mosaicismo , Filogenia , Análise de Sequência de DNA , Vibrio/patogenicidade , Vibrioses/genética , Vibrioses/microbiologia , Vibrioses/veterináriaRESUMO
DjlA is an inner membrane cochaperone belonging to the DnaJ family, which has been shown to be involved in Legionella sp. pathogenesis. In this study, we explored the role of this protein in the physiology and virulence of Vibrio tapetis, the etiological agent of brown ring disease (BRD) in Manila clam (Ruditapes philippinarum). Analysis of the djlA locus in V. tapetis revealed a putative organization in an operon with a downstream gene that we designated duf924(Vt), which encodes a conserved protein with an unknown function and has homologues in bacteria and eukaryotes. djlA mutants displayed a reduced growth rate and showed an important loss of cytotoxic activity against R. philippinarum hemocytes in vitro, which could be restored by extrachromosomal expression of wild-type djlA(Vt) but not duf924(Vt). These results are in keeping with the potential importance of DjlA for bacterial pathogenicity and open new perspectives for understanding the mechanism of action of this protein in the novel V. tapetis-R. philippinarum interaction model.