Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 14 de 14
Filtrar
1.
J Food Prot ; 86(10): 100149, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37633514

RESUMO

Environmental monitoring programs (EMPs) for food production facilities are useful for verifying general sanitation controls and are recommended as verification measures to ensure that the Hazard Analysis Critical Control Point plan is working effectively. In this study, EMPs for Listeria were conducted at three food production facilities to assess the efficacy of sanitation control and establish effective sanitation control methods. In Facility A, L. monocytogenes was detected in the clean area although in Zone 3, non-food-contact surfaces. To prevent contamination from dirty areas, the cleaning practices in the preparation room were investigated. Normal cleaning combined with disinfection with carbonated hypochlorite water (chlorine concentration, 150 ppm) proved effective. At Facility B, a salad product and its ingredients (pastrami and salami) were positive for L. monocytogenes serotype 3b. The bacterial count was <10/g in all samples. However, when inoculated with L. monocytogenes isolates, the growth of approximately 2 log cfu/g was observed on pastrami after 48 h of incubation at 10°C. The ingredients were commercially purchased blocks that were sliced in a slicer at Facility B and used as salad toppings. Because both unopened blocks were negative for L. monocytogenes, contamination of the slicer was suspected. Sampling of the slicer revealed that contamination by L. monocytogenes serotype 3b was more extensive after use than before use. Therefore, the slicer was disassembled, cleaned, and disinfected thoroughly. In Facility C, L. monocytogenes serotype 4b (4e) was detected in all the dirty, semiclean, and clean areas. The strain was also isolated from the wheels of a smoking cart transported across the zones. Therefore, efforts were made to frequently clean and disinfect the cart. EMPs revealed the presence of Listeria in each facility and allowed remedial measures to be undertaken. Continued monitoring and Plan-Do-Check-Act cycles were considered desirable.


Assuntos
Listeria monocytogenes , Listeria , Microbiologia de Alimentos , Contaminação de Alimentos/análise , Contaminação de Equipamentos/prevenção & controle , Monitoramento Ambiental , Instalações Industriais e de Manufatura , Manipulação de Alimentos/métodos
2.
Life (Basel) ; 13(1)2022 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-36675991

RESUMO

Vertebrates have developed a network of blood vessels and nerves throughout the body that enables them to perform complex higher-order functions and maintain homeostasis. The 16th-century anatomical text 'De humani corporis fabrica' describes the networks of blood vessels and nerves as having a branching pattern in which they are closely aligned and run parallel one to another. This close interaction between adjacent blood vessels and nerves is essential not only for organogenesis during development and repair at the time of tissue damage but also for homeostasis and functional expression of blood vessels and nerves. Furthermore, it is now evident that disruptions in neurovascular interactions contribute to the progression of various diseases including cancer. Therefore, we highlight recent advances in vascular biology research, with a particular emphasis on neurovascular interactions.

3.
World Neurosurg ; 90: 518-523, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27025454

RESUMO

OBJECTIVE: Prediction of motor function after intracerebral hemorrhage (ICH) often poses a diagnostic challenge. This study was performed to investigate whether intraoperative monitoring of motor-evoked potentials (MEPs) could predict postoperative motor function recovery. METHODS: We reviewed 16 consecutive patients undergoing evacuation of supratentorial ICH with hemiplegia between June 2011 and October 2014. Patients were categorized according to the results of MEPs before and after evacuation of hematoma. The correlation between detection of MEPs and prognosis of motor function was analyzed. RESULTS: In 10 of 16 cases (62%), stable MEPs were detected before and after evacuation of hematoma, and postoperative motor function was improved in all cases, including 3 cases with severe preoperative motor impairment on manual muscle test (1-2). In 3 cases (19%) in which MEPs were not detected throughout the procedure, motor function was not improved. In the other 3 cases (19%), MEPs were not measured before evacuation of ICH but were detected after evacuation despite poor prognosis of motor function. The results of postevacuation MEPs were considered false-negative results. Predictions using pre-evacuation MEP results were completely consistent with prognosis for recovery, whereas MEPs obtained during and after evaluation were useful for monitoring. CONCLUSIONS: Intraoperative MEPs may indicate preservation of pyramidal tracts, and pre-evacuation MEPs can predict motor function outcome after ICH surgery.


Assuntos
Hemorragia Cerebral/diagnóstico , Hemorragia Cerebral/cirurgia , Potencial Evocado Motor , Monitorização Neurofisiológica Intraoperatória/métodos , Transtornos dos Movimentos/diagnóstico , Transtornos dos Movimentos/etiologia , Avaliação de Resultados em Cuidados de Saúde/métodos , Idoso , Mapeamento Encefálico/métodos , Hemorragia Cerebral/complicações , Feminino , Humanos , Masculino , Transtornos dos Movimentos/prevenção & controle , Procedimentos Neurocirúrgicos/efeitos adversos , Reprodutibilidade dos Testes , Estudos Retrospectivos , Sensibilidade e Especificidade , Resultado do Tratamento
4.
Artigo em Inglês | MEDLINE | ID: mdl-25798155

RESUMO

A 70-year-old man with a history of tongue cancer presented with Fournier's gangrene caused by Listeria monocytogenes serotype 4b. Surgical debridement revealed undiagnosed rectal adenocarcinoma. The patient did not have an apparent dietary or travel history but reported daily consumption of sashimi (raw fish). Old age and immunodeficiency due to rectal adenocarcinoma may have supported the direct invasion of L monocytogenes from the tumour. The present article describes the first reported case of Fournier's gangrene caused by L monocytogenes. The authors suggest that raw ready-to-eat seafood consumption be recognized as a risk factor for listeriosis, especially in cases of skin and soft tissue infection.


Un homme de 70 ans ayant des antécédents de cancer de la langue s'est présenté avec une gangrène de Fournier causée par un Listeria monocytogenes de sérotype 4b. Le débridement chirurgical a révélé un adénocarcinome rectal non diagnostiqué. Le patient n'avait pas d'antécédents alimentaires ou de voyage apparents, mais a déclaré consommer des sashimis (poisson cru) tous les jours.L'âge avancé et l'immunodéficience causée par l'adénocarcinome rectal ont peut-être favorisé l'invasion directe du L monocytogenes par la tumeur. Il s'agit du premier cas déclaré de gangrène de Fournier attribuable au L monocytogenes. Les auteurs proposent d'inclure la consommation de fruits de mer crus prêt-à-manger dans les facteurs de risque de listériose, notamment en cas d'infections de la peau et des tissus mous.

5.
Ann Nucl Med ; 28(2): 94-102, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24272066

RESUMO

OBJECTIVE: The purpose of this study was to examine the (11)C-methionine (MET) and (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) findings of central nervous system (CNS) germinoma and the diagnostic utility of these findings. METHODS: We retrospectively evaluated the cases of 10 patients who were diagnosed with CNS germinoma according to their histopathological or clinical findings. All the patients underwent pretreatment MET and/or FDG-PET scans, and the resultant images were assessed qualitatively and quantitatively. In the qualitative assessments, we used 3- and 5-grade visual scoring systems for the MET- and FDG-PET images, respectively. In the quantitative assessments, the maximal standardized uptake value (SUVmax) and the ratio of the SUVmax of the tumor (T) divided by the mean SUV for the normal white or gray matter [T/N (WM), T/N (GM)], was calculated. RESULTS: The mean and SD values of SUVmax, T/N (WM), and T/N (GM) were 1.9 ± 1.4, 2.5 ± 1.3, and 1.7 ± 0.9 on MET-PET and 5.8 ± 2.2, 1.6 ± 0.5, and 0.8 ± 0.2 on FDG-PET, respectively. On MET-PET, only one lesion was not detected. On the other hand, on FDG-PET all of the lesions exhibited uptake values that were intermediate between those of the normal white matter and gray matter. CONCLUSION: In terms of its tumor-contouring ability, MET is a good tracer for diagnosing CNS germinomas; therefore, MET-PET is considered to be useful for planning biopsies or surgery. Although FDG-PET is capable of detecting CNS germinomas, it produced insufficient image contrast in the present study. Further studies are needed before FDG-PET can be used in clinical examinations of CNS germinoma.


Assuntos
Radioisótopos de Carbono , Neoplasias do Sistema Nervoso Central/diagnóstico por imagem , Fluordesoxiglucose F18 , Germinoma/diagnóstico por imagem , Metionina , Tomografia por Emissão de Pósitrons , Adolescente , Adulto , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Radioisótopos de Carbono/farmacocinética , Criança , Feminino , Fluordesoxiglucose F18/farmacocinética , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Metionina/farmacocinética , Fibras Nervosas Mielinizadas/diagnóstico por imagem , Fibras Nervosas Amielínicas/diagnóstico por imagem , Compostos Radiofarmacêuticos/farmacocinética , Estudos Retrospectivos , Adulto Jovem
6.
Exp Toxicol Pathol ; 65(5): 523-30, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22494849

RESUMO

The sequence of neural progenitor cell (NPC) damage induced in fetal rat brain by transplacental exposure to busulfan, an antineoplastic bifunctional-alkylating agent, on gestational day 13 was examined by immunohistochemical and real-time RT-PCR analyses. Following busulfan treatment, pyknotic NPCs first appeared in the medial layer and then extended to the dorsal layer of the ventricular zone (VZ) of the telencephalon. Pyknotic NPCs that were immunohistochemically positive for cleaved caspase-3, i.e. apoptotic NPCs, began to increase at 24 h after treatment, peaked at 48 h, and returned to the control levels at 96 h. On the other hand, the index (%) of phospho-histone H3-positive NPCs, i.e. mitotic NPCs, and that of BrdU-positive NPCs, i.e. S-phase cells, decreased in accordance with the increase in the index of apoptotic NPCs. Prior to the peak time of apoptotic NPCs, the indices of p53- and p21-positive NPCs peaked at 36 h. In addition, the expression levels of p21 and Puma (p53-target genes) mRNAs were elevated in real-time RT-PCR analysis. These findings indicated that busulfan not only induced apoptosis through the p53-mediated intrinsic pathway but also inhibited cell proliferation in NPCs, resulting in a reduction of the width of the telencephalon. On the other hand, in spite of up-regulation of p21 expression, the expression of cyclin D1, part of the cell cycle machinery of the G1/S transition, and the expression levels of Cdc20 and cyclin B1 which are involved in G2/M transition, showed no changes, giving no possible information of busulfan-induced cell cycle arrest in NPCs.


Assuntos
Alquilantes/toxicidade , Encéfalo/efeitos dos fármacos , Bussulfano/toxicidade , Neurogênese/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Células-Tronco/efeitos dos fármacos , Alquilantes/administração & dosagem , Animais , Apoptose/efeitos dos fármacos , Encéfalo/embriologia , Encéfalo/patologia , Bussulfano/administração & dosagem , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Feminino , Idade Gestacional , Imuno-Histoquímica , Marcação In Situ das Extremidades Cortadas , Exposição Materna/efeitos adversos , Neurônios/patologia , Gravidez , Ratos , Ratos Sprague-Dawley , Reação em Cadeia da Polimerase em Tempo Real , Células-Tronco/patologia , Proteína Supressora de Tumor p53/biossíntese
7.
Clin Nucl Med ; 37(9): 843-9, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22889772

RESUMO

PURPOSE: The aim of our study was to examine the usefulness of PET with C-methionine (MET) and F-fluorodeoxyglucose (FDG) in the differentiation of glioblastoma multiforme (GBM) and intracranial diffuse large B-cell lymphoma (DLBCL). MATERIALS AND METHODS: We evaluated 22 patients retrospectively with an enhancing brain tumor on MRI, including 15 GBM and 7 DLBCL, which was confirmed by histopathology. Dynamic PET scans with MET and FDG were performed for preoperative differential diagnosis. We assessed the images qualitatively and quantitatively. In quantitative assessment, the SUVmax was used on FDG PET and both late and early phases on MET PET. In addition, the ratio of SUVmax in the late and early phases on MET-PET was evaluated (ΔSUVmax). RESULTS: SUVmax on FDG PET of DLBCL was significantly higher than that of GBM. Setting an SUVmax of 12.0 as the cutoff for differentiating DLBCL from GBM, 1 GBM and 1 DLBCL were found to be false-positive and false-negative, respectively.SUVmax in the late and early phases of MET-PET was not significantly different between DLBCL and GBM; however, we also found significant differences in ΔSUVmax on MET-PET. Using ΔSUVmax 1.17 as the cutoff, we could differentiate DLBCL from GBM completely. In the present study, ΔSUVmax on MET-PET was slightly superior to SUVmax on FDG PET. CONCLUSIONS: Both SUVmax on FDG PET and ΔSUVmax on MET-PET were considered to be good diagnostic tests when encountering difficulties in this differential diagnosis.


Assuntos
Fluordesoxiglucose F18 , Glioblastoma/diagnóstico por imagem , Linfoma Difuso de Grandes Células B/diagnóstico por imagem , Metionina , Tomografia por Emissão de Pósitrons , Adulto , Idoso , Idoso de 80 Anos ou mais , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Controle de Qualidade , Estudos Retrospectivos , Adulto Jovem
8.
Infect Genet Evol ; 12(1): 94-101, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22041507

RESUMO

Listeria monocytogenes is a foodborne pathogen that causes gastroenteritis, maternofetal infections and meningoencephalitis in humans. Here we report that an intrahost genome mutation alters bacterial acid resistance and the abilities for replication/invasion in tissue cell culture. Among the L. monocytogenes isolates from the recent outbreak in Japan, we found that one food strain, 668, exhibited the greatest acid resistance, whereas one human clinical strain, 690, sharing identical pulsed-field gel electrophoresis (PFGE) and ribotyping patterns, exhibited an acid-sensitive phenotype. Passage of the 668 food strain through the mouse intestine increased its acid sensitivity without altering the macrogenotypes, indicating intrahost alteration of the bacterial acid-resistant phenotype. Genetic and proteomic analyses revealed a link between acid resistance and SigB (RNA polymerase SigmaB subunit) activity. Compared with the strain 668, the clinical and 4 of 5 mice-passaged strains showed a mutation in the rsbW locus, whose product controls the regulation of SigB activity. Corresponding to the SigB activity, the host-passaged strains had reduced abilities to survive inside macrophages and to invade Caco-2 cells, compared with the food strain 668. Overall, we have demonstrated the first example of a host environment promoting the alteration of SigB-dependent acid resistance and host cell-associated actions of L. monocytogenes. Our study provides new insight into the potential role of intrahost environment in the process of bacterial evolution.


Assuntos
Ácidos/metabolismo , Adaptação Fisiológica , Proteínas de Bactérias/genética , Proteínas de Transporte/genética , Listeria monocytogenes/genética , Fator sigma/genética , Animais , Proteínas de Bactérias/metabolismo , Sequência de Bases , Células CACO-2 , Proteínas de Transporte/metabolismo , Eletroforese em Gel de Campo Pulsado/métodos , Feminino , Microbiologia de Alimentos , Regulação Bacteriana da Expressão Gênica , Humanos , Japão/epidemiologia , Listeria monocytogenes/classificação , Listeria monocytogenes/isolamento & purificação , Macrófagos/microbiologia , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Mutação , Fenótipo , Proteômica , Ribotipagem , Análise de Sequência de DNA , Fator sigma/metabolismo
9.
J Vet Med Sci ; 73(12): 1681-4, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21836384

RESUMO

The antimicrobial susceptibility of 201 Listeria monocytogenes isolates from foods, environments, animals and human patients in Japan was determined. All isolates were susceptible to ampicillin, the first choice of drug for listeriosis treatment, chloramphenicol, dihydrostreptomycin, erythromycin, enrofloxacin, gentamicin, kanamycin, lincomycin, nosiheptide, salinomycin, vancomycin, and virginiamycin. A human strain was resistant to oxytetracycline. The Minimum Inhibitory Concentration (MIC) for 50% of the strains and the MIC for 90% of the strains were comparable in all the isolates. This is the first investigation to compare antibiotic resistances between isolates from foods and isolates from human patients in Japan. The result showed that most of the isolates were susceptible to antibiotics used in this study.


Assuntos
Antibacterianos/farmacologia , Listeria monocytogenes/efeitos dos fármacos , Listeriose/veterinária , Animais , Bovinos , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/microbiologia , Baratas/microbiologia , Farmacorresistência Bacteriana , Fezes/microbiologia , Pisos e Cobertura de Pisos , Fômites , Microbiologia de Alimentos , Humanos , Japão/epidemiologia , Listeriose/epidemiologia , Listeriose/microbiologia , Carne/microbiologia , Testes de Sensibilidade Microbiana
10.
Neurol Med Chir (Tokyo) ; 51(2): 117-9, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21358153

RESUMO

A 55-year-old man presented with intracerebral hemorrhage (ICH) without subarachnoid hemorrhage (SAH) manifesting as acute onset of consciousness disturbance and right hemiparesis. Computed tomography showed ICH mainly localized in the left putamen, but no evidence of SAH. Magnetic resonance angiography demonstrated a cerebral aneurysm originating from the bifurcation of the left internal carotid artery, which was considered to be responsible for the ICH. The patient underwent emergent intravascular surgery for coil embolization of the aneurysm, and his neurological symptoms gradually recovered with rehabilitation after surgery. Although ICH without SAH is a rare presentation of cerebral aneurysm, ruptured cerebral aneurysm should be considered as a potential cause of ICH. The localization and extent of ICH may be suggestive of latent cerebral aneurysm in such cases.


Assuntos
Dissecação da Artéria Carótida Interna/diagnóstico , Artéria Carótida Interna/patologia , Hemorragia Cerebral/diagnóstico , Aneurisma Intracraniano/diagnóstico , Artéria Carótida Interna/fisiopatologia , Dissecação da Artéria Carótida Interna/complicações , Dissecação da Artéria Carótida Interna/patologia , Hemorragia Cerebral/etiologia , Hemorragia Cerebral/patologia , Diagnóstico Diferencial , Humanos , Aneurisma Intracraniano/complicações , Aneurisma Intracraniano/patologia , Masculino , Pessoa de Meia-Idade , Hemorragia Subaracnóidea/diagnóstico
11.
Neurol Med Chir (Tokyo) ; 50(2): 139-43, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20185880

RESUMO

A 21-year-old man presented with a hemorrhagic central neurocytoma manifesting as acute onset of disturbance of consciousness and right hemiparesis. Computed tomography (CT) demonstrated a tumor in the left lateral ventricle during the course of evaluation for mental alteration 12 days before onset, but the tumor was left untreated because the patient refused to visit a neurosurgical institution. CT on admission revealed a large mass lesion located in the body of the lateral ventricle associated with massive intratumoral and intraventricular hemorrhage. He underwent emergent surgery for evacuation of the tumor with hematoma, and his neurological symptoms gradually recovered after surgery. The present case highlights the possibility of rapid deterioration of symptoms by massive hemorrhage from central neurocytoma. Surgical intervention should thoroughly be considered, if intratumoral hemorrhage is present, as hemorrhage from the central neurocytoma may lead to serious neurological complications.


Assuntos
Hemorragia Cerebral/patologia , Neoplasias do Ventrículo Cerebral/patologia , Coma/etiologia , Ventrículos Laterais/patologia , Neurocitoma/patologia , Biomarcadores Tumorais/análise , Encéfalo/irrigação sanguínea , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Hemorragia Cerebral/etiologia , Neoplasias do Ventrículo Cerebral/irrigação sanguínea , Neoplasias do Ventrículo Cerebral/complicações , Progressão da Doença , Serviços Médicos de Emergência/métodos , Serviços Médicos de Emergência/normas , Humanos , Ventrículos Laterais/irrigação sanguínea , Ventrículos Laterais/diagnóstico por imagem , Masculino , Neurocitoma/irrigação sanguínea , Neurocitoma/complicações , Procedimentos Neurocirúrgicos , Paresia/etiologia , Fatores de Tempo , Tomografia Computadorizada por Raios X , Resultado do Tratamento , Ventriculostomia , Adulto Jovem
12.
Artigo em Japonês | MEDLINE | ID: mdl-21381400

RESUMO

Johne disease is ruminant chronic granulomatous enteritis caused by Mycobacterium avium subsp. paratuberculosis (MAP). The domestic animals infected with this pathogen present severe weight loss due to chronic diarrhea and a reduction in lactation yield. These result in enormous economic loss since the affected animals are subsequently subject to artificial selections and disinfection of the environment are absolutely necessary. Furthermore, MAP has been suspected to have pathological relationship to Crohn's disease, human chronic granulomatous enteritis. The bacterium grows slower on solid culture and its colony becomes visible after two months of culture. In Japan, there has been almost no investigation on pasteurization temperature of commercial milk using MAP. It comes from the fact that the growth rate of MAP is very slow and that MAP is a related species to Mycobacterium tuberculosis, which pasteurization condition has been well defined. The studies on the pasteurization conditions of commercial milk have been mainly targeted to reduce the risk of infection to Coxiella and Mycobacterium tuberculosis. However, there has been a concern about the possibility that MAP is remained in pasteurized milk because MAPs form an aggregate and the bacterium at its center may not receive enough heat to get pasteurized. From these reasons, the present study aims to investigate validity of the current pasteurization conditions of commercial milk by implementing experimental pasteurization at various pasteurization temperatures using milk experimentally infected with MAP, and to clarify if MAP is eliminated at these temperatures in order to achieve smooth enforcement of the current ministry order. We conducted plant pasteurization experiment at four pasteurization conditions (high temperature, short time (HTST); 82, 77, 72 degrees C for 15 seconds and low temperature, long time (LTLT); 63 degrees C for 30 minutes) using two MAP strains, ATCC19698 and OKY-20. In conclusion, there appeared no colony of the two MAP strains formed from the milk pasteurized at the four pasteurization conditions examined.


Assuntos
Laticínios , Manipulação de Alimentos , Microbiologia de Alimentos , Leite/microbiologia , Mycobacterium avium subsp. paratuberculosis , Esterilização , Temperatura , Animais , Indústria de Processamento de Alimentos , Humanos
13.
FEMS Microbiol Lett ; 263(1): 54-60, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16958851

RESUMO

Listeria monocytogenes is able to grow under conditions of high osmolarity. We constructed a deletion mutant of rpoN, encoding the alternative sigma factor RpoN, and analyzed its response to osmotic stress. In a minimal medium with 4% NaCl and 1 mM betaine, the mutant showed a similar growth to that of the parental strain, EGD. In the same medium with 4% NaCl and 1 M carnitine, the growth rate of the mutant was greatly reduced, when the optical density at 600 nm (OD600) at the starting point of growth, was 0.15. However, when growth of the culture was started at an OD600 of 0.025, the growth of the mutant was similar to that of EGD. The mutant's expression of two betaine transporter genes, betL and gbuB, and the carnitine transporter gene opuCA, was osmotically induced at a level similar to EGD, and its rate of carnitine uptake was similar to that of EGD. These results suggest that the growth defect from the rpoN mutant is caused not by the transcriptional regulation of opuCA or by a decrease in carnitine uptake, but possibly by larger amounts of carnitine being needed for growth of the mutant in minimal medium when NaCl is present.


Assuntos
Listeria monocytogenes/genética , Listeria monocytogenes/fisiologia , RNA Polimerase Sigma 54/fisiologia , Proteínas de Bactérias/genética , Betaína/metabolismo , Carnitina/metabolismo , Proteínas de Transporte/genética , Meios de Cultura , Deleção de Genes , Genoma Bacteriano , Glicina/metabolismo , Proteínas de Membrana Transportadoras/genética , Mutação , Proteínas de Transporte de Cátions Orgânicos/genética , Concentração Osmolar , RNA Polimerase Sigma 54/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Cloreto de Sódio/metabolismo
14.
Appl Environ Microbiol ; 68(4): 1541-7, 2002 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11916666

RESUMO

Transposon insertional mutants of Listeria monocytogenes were constructed to identify genes involved in osmotolerance, and one mutant that showed reduced growth under high osmotic pressure was obtained. The cloned gene from the transposon insertion site of the mutant, named rel, was 2,214 bp in length and had very high homology to relA of Bacillus subtilis, which encodes guanosine tetraphosphate (ppGpp) and guanosine pentaphosphate (pppGpp) [collectively designated (p)ppGpp] synthetase during stringent response. The mutant showed a deficiency in (p)ppGpp accumulation. In the parental strain, the amount of intracellular (p)ppGpp was not increased after an osmotic upshift but was slightly decreased compared with the level before the upward shift. The reduced osmotolerance of the mutant was restored to a level almost equal to that of the parent strain when the chromosomal region that included rel of L. monocytogenes was introduced into the mutant. After exposure to methyl glucoside, the rel mutant accumulated (p)ppGpp at a higher level than the basal level and partially restored the ability to grow in NaCl-supplemented brain heart infusion broth. The mutant was found to grow in chemically defined minimal medium supplemented with glycine betaine or carnitine, so-called compatible solutes, and 4% NaCl. Our results suggest that the appropriate intracellular concentration of (p)ppGpp is essential for full osmotolerance in L. monocytogenes and that its mechanism is different from that for the accumulation of compatible solutes.


Assuntos
Clonagem Molecular , Ligases/genética , Listeria monocytogenes/fisiologia , Sequência de Aminoácidos , Animais , Meios de Cultura , Elementos de DNA Transponíveis , Feminino , Guanosina Pentafosfato/biossíntese , Ligases/metabolismo , Listeria monocytogenes/enzimologia , Listeria monocytogenes/genética , Listeria monocytogenes/patogenicidade , Listeriose/microbiologia , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Mutagênese Insercional , Concentração Osmolar , Análise de Sequência de DNA , Virulência
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA