RESUMO
There is little information available on Xylella fastidiosa transmission by spittlebugs (Hemiptera, Cercopoidea). This group of insect vectors may be of epidemiological relevance in certain diseases, so it is important to better understand the basic parameters of X. fastidiosa transmission by spittlebugs. We used grapevines as a host plant and the aphrophorid Philaenus spumarius as a vector to estimate the effect of plant access time on X. fastidiosa transmission to plants; in addition, bacterial population estimates in the heads of vectors were determined and correlated with plant infection status. Results show that transmission efficiency of X. fastidiosa by P. spumarius increased with plant access time, similarly to insect vectors in another family (Hemiptera, Cicadellidae). Furthermore, a positive correlation between pathogen populations in P. spumarius and transmission to plants was observed. Bacterial populations in insects were one to two orders of magnitude lower than those observed in leafhopper vectors, and population size peaked within 3 days of plant access period. These results suggest that P. spumarius has either a limited number of sites in the foregut that may be colonized, or that fluid dynamics in the mouthparts of these insects is different from that in leafhoppers. Altogether our results indicate that X. fastidiosa transmission by spittlebugs is similar to that by leafhoppers. In addition, the relationship between cell numbers in vectors and plant infection may have under-appreciated consequences to pathogen spread.
Assuntos
Hemípteros/microbiologia , Insetos Vetores/microbiologia , Doenças das Plantas/microbiologia , Vitis/microbiologia , Xylella/fisiologia , Animais , Interações Hospedeiro-PatógenoRESUMO
The detection of preformed donor-specific alloantibodies (DSA) with multiplex-bead arrays has led to the common observation that individuals without a history of pregnancy, transfusion or transplantation can have circulating anti-HLA antibodies of unknown etiology. We retrospectively analyzed the risk of antibody-mediated rejection (AMR) and graft outcome in 41 kidney transplant recipients with DSA of unknown etiology (DSA cause-unk) at the time of transplantation. Twenty-one patients received a posttransplantation desensitization protocol, and 20 received standard immunosuppressive therapy. The mean number of DSA was 1.4 ± 0.8, ranging from 1 to 5. Complement-dependent cytotoxicity crossmatches were negative for all the patients. Flow cytometry crossmatches were positive in 47.6% of cases. The incidence of acute AMR was 14.6% at 1 year, regardless of the immunosuppressive regimen. No patients experienced graft loss following AMR. At month 12, across the entire population of patients with DSA cause-unk, the outcomes were favorable: the measured glomerular filtration rate was 63.8 ± 16.4 mL/min/1.73 m(2), the screening biopsies showed low frequencies of microvascular inflammation and no transplant glomerulopathy, and graft and patient survival were 100%. In conclusion, patients with DSA cause-unk are able to mount AMR but have favorable 1-year outcomes.
Assuntos
Isoanticorpos/imunologia , Transplante de Rim , Doadores de Tecidos , Adulto , Dessensibilização Imunológica , Rejeição de Enxerto/imunologia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do TratamentoRESUMO
Bacterial Leaf Blight of rice (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a major threat for food security in many rice growing countries including Burkina Faso, where the disease was first reported in the 1980's. In line with the intensification of rice cultivation in West-Africa, BLB incidence has been rising for the last 15 years. West-African strains of Xoo differ from their Asian counterparts as they (i) are genetically distant, (ii) belong to new races and, (iii) contain reduced repertoires of Transcription Activator Like (TAL) effector genes. In order to investigate the evolutionary dynamics of Xoo populations in Burkina Faso, 177 strains were collected from 2003 to 2018 in three regions where BLB is occurring. Multilocus VNTR Analysis (MLVA-14) targeting 10 polymorphic loci discriminated 24 haplotypes and showed that Xoo populations were structured according to their geographical localization and year of collection. Considering their major role in Xoo pathogenicity, we assessed the TAL effector repertoires of the 177 strains upon RFLP-based profiling. Surprisingly, an important diversity was revealed with up to eight different RFLP patterns. Finally, comparing neutral vs. tal effector gene diversity allowed to suggest scenarios underlying the evolutionary dynamics of Xoo populations in Burkina Faso, which is key to rationally guide the deployment of durably resistant rice varieties against BLB in the country.
RESUMO
Antibody-mediated allograft rejection is an increasingly recognized problem in clinical transplantation. However, the primary location of donor-specific alloantibody (DSA)-producing cells after transplantation have not been identified. The purpose of this study was to test the contribution of allospecific antibody-secreting cells (ASCs) from different anatomical compartments in a mouse transplantation model. Fully MHC-mismatched heart allografts were transplanted into three groups of recipients: nonsensitized wild type, alloantigen-sensitized wild-type and CCR5(-/-) mice that have exaggerated alloantibody responses. We found that previous sensitization to donor alloantigens resulted in the development of antidonor alloantibody (alloAb) with accelerated kinetics. Nevertheless, the numbers of alloantibody-secreting cells and the serum titers of antidonor IgG alloantibody were equivalent in sensitized and nonsensitized recipients 6 weeks after transplantation. Regardless of recipient sensitization status, the spleen contained higher numbers of donor-reactive ASCs than bone marrow at days 7-21 after transplantation. Furthermore, individual spleen ASCs produced more antidonor IgG alloantibody than bone marrow ASCs. Taken together, our results indicate that the spleen rather than bone marrow is the major source of donor-reactive alloAb early after transplantation in both sensitized and nonsensitized recipients.
Assuntos
Formação de Anticorpos , Transplante de Coração , Modelos Animais , Baço/imunologia , Animais , Ensaio de Imunoadsorção Enzimática , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Doadores de Tecidos , Transplante HomólogoRESUMO
The INHIBITOR OF MERISTEM ACTIVITY in tomato (SlIMA) and MINI ZINC FINGER 2 in Arabidopsis (AtMIF2), two members of the MINI ZINC FINGER family (MIF), are involved in the regulation of flower and ovule development. MIF proteins possess a unique non-canonical zinc-finger domain that confers the capacity to interact with other protein partners. The characterization of SlIMA and AtMIF2 gain- and loss-of-function transgenic lines in Solanum lycopersicum and Arabidopsis thaliana respectively, allowed the demonstration of their conserved functional role in the termination of floral stem cell maintenance. During early floral development, the expression of SlIMA and AtMIF2 is induced by the MADS-Box transcription factor AGAMOUS (AG). Then, SlIMA or AtMIF2 protein recruits the C2H2 zinc finger KNUCKLES (KNU), in a transcriptional repressor complex together with TOPLESS (TPL) and HISTONE DEACETYLASE19 (HDA19). This complex binds to the WUSCHEL (WUS) locus leading to its repression. To further characterize the role of these interactions in flower development, we have investigated the effects of a dominant negative form of SlIMA, SlIMAch that leads to spectacular phenotypes, including ovule conversion into a floral meristem.
Assuntos
Flores/metabolismo , Óvulo Vegetal/metabolismo , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Solanum lycopersicum/metabolismo , Flores/genética , Regulação da Expressão Gênica no Desenvolvimento/genética , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Solanum lycopersicum/genética , Meristema/genética , Meristema/metabolismo , Óvulo Vegetal/genética , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genéticaRESUMO
The mutagenic properties of acridines on pneumococcus are described. All seven acridines tested were mutagenic at the amiA locus conferring a resistance to 10(-5) M aminopterin. The effects of quinacrine were more specifically investigated. It was observed that: mutants can be obtained only by treatment of exponentially growing cells; a sharp maximum mutagenic effect occurs at a concentration slightly lower than the bacteriostatic value; and the amount of quinacrine required to yield the maximum mutagenic effect decreases with the pH of the medium. Moreover, the number of mutants detected after quinacrine treatment varies from locus to locus. The majority of quinacrine-induced mutants are readily reverted by quinacrine, but not by nitrosoguanidine treatment. This suggests that in pneumococcus quinacrine induces mainly frameshift mutations. A further study of the revertants obtained by quinacrine treatment of quinacrine-induced mutants strengths this interpretation: most of the revertants result from a mutation at the same site; some partial revertants exhibiting an intermediate resistance to aminopterin were found to contain two very closely linked mutated sites, each mutation conferring the maximum level of resistance to aminopterin. Thus, the majority of quinacrine-induced mutants at the amiA locus of pneumococcus consists of frameshift mutations. Nearly all of the isolated mutants induced by quinacrine as well as other acridines belong to the low efficiency class of transformation. It was concluded that the mismatch resulting from the pairing between the wild type and the frameshift-containing sequence is recognized by the excision-repair system involved in the discrimination function in a way similar to that in which it recognizes mismatched base pairs between a transition mutation and the wild-type sequence.
Assuntos
Acridinas/farmacologia , Resistência Microbiana a Medicamentos , Mutação , Streptococcus pneumoniae/genética , Aminopterina/farmacologia , Código Genético , Mutagênicos , Quinacrina/farmacologia , Streptococcus pneumoniae/efeitos dos fármacos , Transcrição GênicaRESUMO
The use as genetic markers, during transformation of Streptococcus pneumoniae, of 19 sequences differing from wild type, located throughout the amiA locus, enabled us to examine the fate of 24 single- and 11 multiple-mismatches during recombination. Tentative mismatch ranking as a function of decreasing repair efficiency by the Hex mismatch repair system is G/T = A/C = G/G (maximum repair: 90-95%) greater than C/T (mostly 75 to 90% repair) greater than A/A (from 50 to 90% repair) greater than T/T (50-65% repair) greater than A/G (from 0 to 20% repair) greater than C/C. No indication of correction of the latter has been obtained. Over the limited number of samples examined, we observed no influence of the base composition of the surrounding sequence on correction efficiency for both transition mismatches and for G/G and C/C. Variations in the surrounding sequence affect repair of A/G and C/T, and, even more strongly, of A/A and T/T. No simple correlation to the G:C content of the surrounding sequence is apparent from our results, in contrast to the conclusion drawn for the Mut mismatch repair system of Escherichia coli. Examination of the fate of multiple mismatches suggests that C/C may sometimes impede recognition of otherwise corrected mismatches.
Assuntos
Reparo do DNA , DNA Bacteriano/genética , Recombinação Genética , Streptococcus pneumoniae/genética , Composição de Bases , Escherichia coli/genética , Marcadores Genéticos , Transformação BacterianaRESUMO
We have constructed a shuttle vector that replicates in Escherichia coli, Corynebacterium glutamicum and Brevibacterium lactofermentum, by fusion of a 4.4-kb cryptic plasmid isolated from B. lactofermentum and a derivative of pBR322. Resistance to erythromycin which is expressed in all three bacteria has been a useful selective marker. The frequency of homospecific transformation was 1.5 X 10(5) transformants/micrograms of hybrid plasmid DNA.
Assuntos
Brevibacterium/genética , Vetores Genéticos , Brevibacterium/efeitos dos fármacos , Corynebacterium/genética , DNA Bacteriano/genética , Eritromicina/farmacologia , Escherichia coli/genética , Plasmídeos , Fatores R , Transformação GenéticaRESUMO
A method for the rapid cloning of specific Streptococcus pneumoniae DNA fragments depends on the integration by homologous recombination into the bacterial chromosome of a plasmid which carries an insert of S. pneumoniae DNA, but which cannot be autonomously maintained in S. pneumoniae. Selection for plasmid integration employs aminopterin or erythromycin resistance. Host sequences adjacent to the site of insertion are easily cloned by enzymatic excision and recircularization of the plasmid, followed by propagation in Escherichia coli. This is particularly useful for repeated cloning of a given fragment that carries various mutations.
Assuntos
Clonagem Molecular/métodos , DNA Bacteriano , Genes Bacterianos , Recombinação Genética , Streptococcus pneumoniae/genética , Aminopterina/farmacologia , Cromossomos Bacterianos , DNA Recombinante , Mutação , Plasmídeos , Streptococcus pneumoniae/efeitos dos fármacos , Transformação BacterianaRESUMO
EcoRI fragments of the amiA locus in Streptococcus pneumoniae were cloned either into a derivative of lambda or into pBR325 plasmid. Mutations in the amiA locus confer resistance to aminopterin. Pneumococcal DNA fractions were enriched for the desired EcoRI fragments by agarose gel electrophoresis. Recombinant clones were detected directly by transformation with DNA and lambda plaques or from single-colony lysates containing pBR325. The use of cloned DNA in pneumococcal transformation has revealed a number of features pertinent to transformation in general, and also the mismatch repair process. High transformation levels can be achieved, from 40 to 80% of a competent culture. These high levels of transformation with cloned DNA made in a foreign host are taken to confirm the absence of restriction effects on transformation in S. pneumoniae. At saturation, similar transformation levels are obtained with hybrid phage or hybrid plasmid DNAs, but the DNA amount required is 20 to 25 times lower for hybrid plasmid than for hybrid phage, probably because plasmid DNA is 10 times shorter than phage DNA. There is no "end effect" with intact hybrid DNA, i.e. similar transformation levels are achieved for markers whatever their map position on the cloned pneumococcal fragment. Cloned DNA has been used to study the action of the mismatch repair process (hex system). The presence of two mismatches in the same cell is not enough to saturate the hex system, and is not enough to kill the colony-forming center (cfc).
Assuntos
Reparo do DNA , DNA Bacteriano/genética , Streptomyces/genética , Transformação Bacteriana , Aminopterina/farmacologia , Bacteriófago lambda , Clonagem Molecular , DNA Recombinante , Resistência Microbiana a Medicamentos , PlasmídeosRESUMO
In genetic transformation, long deletions dramatically increase the frequency of wild-type recombinants in 2-point crosses. In 3-point crosses in which the deletion was localized between 2 point mutations we demonstrated that this hyper-recombination was the result of genetic conversion extending over several scores of bases outside the deletion. As this conversion did not require an active DNA polymerase A gene, it was proposed that the mechanism of conversion involves breakage and ligation between DNA molecules. A similar hyper-recombination was observed when donor DNA carried an insertion. These results suggest that long heterologies participated in recombination so that surrounding homologous regions are almost completely paired and that these long heterologies are converted. It appears that it is a process that evolved to correct errors of replication which lead to long deletions and which are not eliminated by other systems.
Assuntos
Deleção Cromossômica , Recombinação Genética , Streptococcus pneumoniae/genética , Transformação GenéticaRESUMO
In order to facilitate genetic engineering in amino-acid producing bacteria we have isolated two restriction-deficient Brevibacterium lactofermentum strains. They have been selected for their ability to obtain a high yield of plaques from CL31 phage which was grown on Corynebacterium lilium. These mutant strains do not restrict either phage DNA by transfection or DNA from the shuttle vector pBLA extracted from Escherichia coli by protoplast transformation. These mutants have also lost modification activity. We also report the presence of a restriction modification system in C. lilium ATCC 15990.
Assuntos
Brevibacterium/genética , Mutação , Transfecção , Transformação Bacteriana , Bacteriófagos/genética , Bacteriófagos/crescimento & desenvolvimento , Corynebacterium/metabolismo , DNA Viral/metabolismo , Nitrosoguanidinas/farmacologia , Ensaio de Placa ViralRESUMO
Wild-type strains of Streptococcus pneumoniae were non-mutable by UV radiation and thymidine starvation. Moreover, UV-irradiated pneumococcal omega 2 phages were not reactivated in an irradiated host. This suggests that, in pneumoococcus, there is no efficient inducible repair process similar to the SOS repair described in detail for E. coli. We also report that mutations cannot be induced by a process thought to be linked to competence during transformation with isogenic wild-type DNA either on wild-type strains or in strains in which the hex function of excision and repair of mismatched bases is inactive.
Assuntos
Bacteriófagos/genética , Reparo do DNA , Lisogenia/efeitos da radiação , Streptococcus pneumoniae/genética , Ativação Viral , Bacteriófagos/crescimento & desenvolvimento , Mutação , Streptococcus pneumoniae/efeitos da radiação , Transformação Bacteriana , Raios UltravioletaRESUMO
The French Academy of Surgery was not created easily largely due to the frequent quarrels between physician and surgeons. Founded in 1731, it experiented many trials and tribulations for three centuries. Disbanded in 1793 by the Convention, it was transformed into Société Nationale in 1843 and only regained the name of Académie in 1935.
Assuntos
Academias e Institutos/história , Cirurgia Geral/história , Sociedades Médicas/história , França , História do Século XVIII , História do Século XIX , História do Século XXRESUMO
Doctors can play an essential role in the epidemiology of road accidents. Problems of vision are important and require new legislation as a result of recent studies. Fatigue, drowsiness and falling asleep among driver is recognized in approximately 30% of cases. Better information should take into account recent surveys underlining the frequency of this problem. The taking of licit or illicit drugs is a non-negligible factor in the loss of control of a vehicle during prolonged journeys, and is particularly aggravated by alcohol. Users, of whom there are many in France according to statistics, should be better informed about the risks, both by clear warnings on containers and by the prescribing doctors. Of all causes of accidents, those that are about to be discussed are among the most frequent. Their prevention should diminish road mortality, a veritable national scourge.
Assuntos
Acidentes de Trânsito/prevenção & controle , Acidentes de Trânsito/legislação & jurisprudência , França/epidemiologia , Humanos , IncidênciaRESUMO
Cervico-vaginal smears were quite difficult to accept when they were first introduced in France, during the fifties, probably due to a fear that cytology might replace surgical pathology, whereas both methods may develop close together. At last, bridging the gap was accomplished by the pathologists and, nowadays, a number of cytopathologists have been trained and have become quite clever. Obviously, clinicians cannot do without the method described by George N. Papanicolaou (the so-called Pap test). Although cervical carcinoma is the very one cancer that should have been eradicated, as complete recovery is the rule when the diagnosis is made in time, at the preinvasive stage of the tumor, in France it is still responsible for 2000 annual deaths. Systematical target population screening should be organized, as well as in other countries and should become one of the main priorities of health care control.
Assuntos
Teste de Papanicolaou , Esfregaço Vaginal/história , Feminino , França , História do Século XX , HumanosRESUMO
A study of 1,427 case records permitted the authors to discover 10 cases of reoperation for sciatica which appeared on the opposite side after removal of a dischernia. A new hernia was noted in 6 cases, whereas radiculitis of unknown origin, appeared to be responsible in 4 cases. The 10 patients who became cured, either after removal of the hernia, or after decompression through the foramin. These few cases, in fact rare, may be considered as relapses and thus poor surgical results. The provide a contribution to the understanding of intervertebral disc disease and raise an interesting medico-legal problem.
Assuntos
Deslocamento do Disco Intervertebral/cirurgia , Complicações Pós-Operatórias , Ciática/etiologia , Adulto , Idoso , Feminino , Humanos , Deslocamento do Disco Intervertebral/complicações , Masculino , Pessoa de Meia-Idade , Radiculopatia/complicaçõesRESUMO
Osteoblastoma is a rare bony tumour. Its localisation at the level of the patella seems exceptional. Our case is the third published case. Wide curetage was a failure, and did not permit histological diagnosis. A cure was obtained by patellectomy, after which the diagnosis of the lesion was made without any doubt.
Assuntos
Neoplasias Ósseas , Osteoma Osteoide , Patela , Idoso , Neoplasias Ósseas/diagnóstico por imagem , Neoplasias Ósseas/patologia , Feminino , Humanos , Osteoma Osteoide/diagnóstico por imagem , Osteoma Osteoide/patologia , Patela/diagnóstico por imagem , Patela/patologia , RadiografiaRESUMO
When handling vocal pathologies, speech therapists need tools to visualise voice and speech, in order to correlate personal auditory analysis with accurate data. Vocalab2 is a spectral analysis tool designed for speech therapists, developed in partnership with INSA Toulouse, France. Vocalab is a simple and user-friendly tool with important features to be used during evaluation and therapy. The software is based on a set of phoniatric data and sophisticated real-time signal analysis (Fourier transform, fundamental detection). One of the key tools of Vocalab2 is the real-time spectrum for visualising, differentiating and comparing every cord approximation and speech movement. Animations are proposed for illustrating most phonemes, and videos related to folding cords in the case of pathologic and normal sound production are also proposed. An extensive test has been conducted during 18 month, with important feedback that has considerably improved the tool. The satisfaction ratio is around 8/10.
Assuntos
Software , Fonoterapia/métodos , Distúrbios da Voz/diagnóstico , Treinamento da Voz , Acústica , Humanos , Idioma , Fonética , Gravação em Vídeo , Distúrbios da Voz/classificaçãoRESUMO
An interallied military delegation went to Spandau, a Berlin suburb, in order to realize the health state of some main Nazis accused of crimes against mankind and waiting to appear before the Nürnberg Court of Justice.