RESUMEN
BACKGROUND: Antibody-mediated and cytotoxic T cell-mediated pathogenicity have been implicated as the autoimmune pathophysiologic mechanisms in Rasmussen's encephalitis. METHODS: The authors investigated autoantibodies against the NMDA glutamate receptor (GluR) epsilon2 subunit and their epitopes in serum and CSF samples from 15 patients with chronic epilepsia partialis continua (EPC), 17 with West syndrome, 10 with Lennox-Gastaut syndrome, and 11 control subjects. RESULTS: In 15 patients with chronic EPC, we detected NMDA-type GluR epsilon2 autoantibodies in histologically proven Rasmussen's encephalitis (3/3 patients), clinical Rasmussen's encephalitis (6/7 patients), acute encephalitis/encephalopathy (2/3 patients), and nonprogressive EPC (2/2 patients). Serum IgM autoantibodies were found in the early phase of EPC and became negative later in four patients. The autoantibodies were not detected in West syndrome, Lennox-Gastaut syndrome, or controls. Among 10 patients with histologically proven or clinical Rasmussen's encephalitis, epitope analyses showed that the autoantibodies were predominantly against C-terminal epitopes and rarely against N-terminal epitope, with inconsistency in profile during the courses of disease. Epitope recognition spectrum of autoantibodies was broader in CSF than in serum, and the serum or CSF profile showed an increase in number of epitopes as disease progressed in some patients. CONCLUSIONS: The presence of autoantibodies against NMDA GluR epsilon2 suggests autoimmune pathologic mechanisms but is not a hallmark of Rasmussen's encephalitis. Patients with Rasmussen's encephalitis may have autoantibodies against several neural molecules, and these autoantibodies may be produced in the CNS after cytotoxic T cell-mediated neuronal damage.
Asunto(s)
Autoanticuerpos/sangre , Encefalitis/inmunología , Epilepsia Parcial Continua/inmunología , Receptores de N-Metil-D-Aspartato/inmunología , Espasmos Infantiles/inmunología , Adolescente , Adulto , Autoanticuerpos/líquido cefalorraquídeo , Niño , Preescolar , Enfermedad Crónica , Progresión de la Enfermedad , Encefalitis/sangre , Encefalitis/líquido cefalorraquídeo , Epilepsia Parcial Continua/sangre , Epilepsia Parcial Continua/líquido cefalorraquídeo , Epítopos/inmunología , Femenino , Humanos , Lactante , Masculino , Valor Predictivo de las Pruebas , Subunidades de Proteína/inmunología , Valores de Referencia , Pruebas Serológicas , Espasmos Infantiles/sangre , Espasmos Infantiles/líquido cefalorraquídeo , SíndromeRESUMEN
An intriguing mutant was isolated in Schizosaccharomyces pombe, which is defective in the maintenance of viability after entry into the stationary phase. In the logarithmic growth phase, the mutant cells grow at the same rate as the parental cells. Upon the onset of the stationary phase, however, the mutant cells lose viability very rapidly. It was found that this phenotype was due to a mutational lesion in the lcf1+ gene, which encodes a long-chain fatty acyl-CoA synthetase. The lcf1Deltamutant shows pleiotropic phenotypes, in that they are also sensitive to high temperature (37 degrees C) and to high salt concentrations (0.9 M KCl) in the medium. Based on the fact that Lcf1 is highly homologous to Faa1 and Faa4 of Saccharomyces cerevisiae, both of which have previously been suggested to play roles in the maintenance of endogenous acyl-CoA pools, the possible function of Lcf1 in S. pombe is discussed.
Asunto(s)
Coenzima A Ligasas/genética , Schizosaccharomyces/genética , Coenzima A Ligasas/metabolismo , Mutación , ARN Mensajero/metabolismo , Schizosaccharomyces/metabolismo , Eliminación de SecuenciaRESUMEN
The bacterial community present during semicontinuous treatment of organic solid waste under alkaline and high-temperature conditions was studied. PCR-amplified 16S rDNA fragments were analyzed by double gradient-denaturing gradient gel electrophoresis (DGGE). The band pattern was stable during the steady state of the treatment phase, and the major bands resulting from individual treatments had the same DNA sequence with good reproducibility. No sequence in the DNA database of isolated bacteria showed close similarity to this sequence, the closest relative being Bacillus licheniformis with less than 97% similarity. The conditions for fluorescence in situ hybridization (FISH) were determined without the need to obtain extracts of the bacterial cells. An oligonucleotide probe was designed to detect the microorganisms found in the DGGE analysis. FISH analysis showed that the bacterium corresponding to the major bands accounted for 30% of the total eubacterial cell count at the steady state. These results indicate that this bacterium is a key microorganism in the biodegradation process.
Asunto(s)
Bacterias/metabolismo , Eliminación de Residuos , Bacterias/genética , Bacterias/crecimiento & desarrollo , Biodegradación Ambiental , ADN Bacteriano/genética , Ecosistema , Electroforesis en Gel de Poliacrilamida/métodos , Hibridación Fluorescente in Situ , Análisis de Secuencia , TemperaturaRESUMEN
BACKGROUND: Most Japanese pediatric neurologists attempt other treatments before using adrenocorticotropic hormone (ACTH) therapy for West syndrome (WS), and even then, they use only a low-dose synthetic ACTH to avoid serious adverse effects. In this multi-institutional study, the authors analyzed the initial effects, adverse effects, and long-term outcome in patients treated with low-dose synthetic ACTH in Japan. METHODS: The medical records of 138 patients with WS, who were treated with low-dose synthetic ACTH therapy for the first time at the authors' institutions between 1989 and 1998, were analyzed. RESULTS: At the end of ACTH therapy, excellent effect on seizures was noted in 106 of 138 (76%) patients, good effect in 23 (17%), and poor effect in 9 (7%). Initial effects on EEG were excellent in 53 of 138 (38%) patients, good in 76 (55%), and poor in 9 (7%). As for seizure prognosis at the time of follow-up, 51 of 99 (52%) patients were seizure-free, whereas 48 (48%) patients had seizures. Mental outcome was normal in 6 of 98 (6%) patients, mild mental retardation in 16 (16%), moderate mental retardation in 26 (27%), and severe mental retardation in 50 (51%). The initial effects of ACTH on seizures and long-term outcome were not dose dependent (daily dosage 0.005 to 0.032 mg/kg, 0.2 to 1.28 IU/kg; total dosage 0.1 to 0.87 mg/kg, 4 to 34.8 IU/kg). The severity of adverse effects correlated with total dosage of ACTH, and the severity of brain volume loss due to ACTH correlated well with the daily dosage and total dosage of ACTH. CONCLUSION: Low-dose synthetic ACTH therapy is as effective for the treatment of WS as the higher doses used in previous studies. The dosage of synthetic ACTH used in the treatment of WS can be decreased as much as possible to avoid serious adverse effects.
Asunto(s)
Cosintropina/administración & dosificación , Espasmos Infantiles/tratamiento farmacológico , Encéfalo/efectos de los fármacos , Cosintropina/efectos adversos , Electroencefalografía/efectos de los fármacos , Femenino , Estudios de Seguimiento , Humanos , Lactante , Discapacidad Intelectual/etiología , Masculino , Estudios Retrospectivos , Espasmos Infantiles/complicaciones , Espasmos Infantiles/fisiopatologíaRESUMEN
OBJECTIVES: Children with cerebral injury often exhibit brief muscle contraction to a variety of stimuli. However, it remains to be determined whether or not the pattern of the reaction is stereotypical irrespective of the site stimulated. To answer this question, we studied electromyographic (EMG) responses to three types of stimuli in children. METHODS: The EMG responses of cranial and limb muscles were recorded after acoustic or somaesthetic stimulation in 6 patients and 23 control subjects. RESULTS: Acoustic stimuli evoked patterned motor activity with a rostrocaudal progression. Nose-tapping stimuli elicited reflex EMG activity in the VIIth cranial muscles that was similar to the R1 component of the electrical blink reflex. Sternum-tap stimuli evoked motor activity in the sternocleidomastoid and arm muscles, and this reflex was probably mediated through the cervical cord (H-reflex). Moreover, late reflexes were evoked following these early reflexes in the patients. In particular, atypical forms of myoclonic jerks were evoked on sternum-tap stimuli. CONCLUSIONS: Many types of primitive reflexes were evoked following three types of stimuli. These reflexes included startle reflex, trigeminomotor reflex, H-reflex and atypical forms of myoclonus, and they were enhanced in the patient group. There are many startle-mimicking reflexes.
Asunto(s)
Electromiografía , Músculo Esquelético/fisiología , Reflejo de Sobresalto/fisiología , Estimulación Acústica , Parpadeo/fisiología , Lesiones Encefálicas/fisiopatología , Niño , Preescolar , Electroencefalografía , Potenciales Evocados Auditivos del Tronco Encefálico/fisiología , Femenino , Humanos , Lactante , Masculino , Nariz/fisiología , Estimulación Física , Esternón/fisiologíaRESUMEN
We report a novel post-transcriptional control of the ptsG gene encoding the major glucose transporter IICB(Glc). We demonstrate that the level of IICB(Glc) is markedly reduced when the glycolytic pathway is blocked by a mutation in either the pgi or pfkA gene encoding phosphoglucose isomerase or phosphofructokinase, respectively. This down-regulation of ptsG is not exerted at the transcriptional level. Both northern blot and S1 analyses demonstrate that the mutation dramatically accelerates the degradation of ptsG mRNA. The degradation of ptsG mRNA occurs in wild-type cells when alpha-methylglucoside, a non- metabolizable analog of glucose, is present in the medium. The addition of any one of the glycolytic intermediates downstream of the block prevents the degradation of ptsG mRNA. The rapid degradation of ptsG mRNA is eliminated when RNase E is thermally inactivated. We conclude that the glycolytic pathway controls ptsG expression by modulating RNase E-mediated mRNA degradation. This is the first instance in which the glycolytic flux has been shown to affect the expression of a specific gene through mRNA stability.
Asunto(s)
Escherichia coli/genética , Escherichia coli/metabolismo , Regulación Bacteriana de la Expresión Génica , Glucólisis/fisiología , Operón Lac/fisiología , Sistema de Fosfotransferasa de Azúcar del Fosfoenolpiruvato/genética , ARN Mensajero/metabolismo , Ciclo del Ácido Cítrico , Endorribonucleasas/metabolismo , Escherichia coli/efectos de los fármacos , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Regulación Enzimológica de la Expresión Génica , Genotipo , Glucosa/metabolismo , Glucosa/farmacología , Operón Lac/efectos de los fármacos , Metilglucósidos/farmacología , ARN Mensajero/genéticaRESUMEN
OBJECTIVE: In Japan, >200 children with influenza virus-associated encephalopathy were reported in 1999 and the mortality rate was high. The levels of tumor necrosis factor-alpha (TNFalpha) and interleukin-6 (IL-6) in both CSF and serum were significantly increased in severe cases. The authors found a correlation between elevated serum cytokine levels and mortality and neurologic morbidity. METHODS: TNFalpha, IL-6, soluble tumor necrosis factor receptor 1 (sTNF-R1), interferon-gamma (IFNgamma), and IL-2 were measured by the ELISA method in sera from six children with encephalopathy before and during therapy, and in six age-matched controls with influenza type A virus infection. RESULTS: The increases in the serum TNFalpha, IL-6, and sTNF-R1 levels were statistically significant at the onset of symptoms before therapy, but the IL-6 level was most useful for diagnosis. The serum IL-6 levels were >6,000 pg/mL in children with brain stem dysfunction, about 150 pg/mL in children without brain stem dysfunction, and <80 pg/mL in controls. The time course of the serum IL-6 level also reflected the clinical condition. Once the serum IL-6 level was increased to >15,000 pg/mL, none of the children survived. The lower the maximal serum IL-6 level, the milder the CNS sequelae. CONCLUSION: The serum IL-6 level may be the most useful indicator for the diagnosis and the clinical severity of influenza virus-associated encephalopathy.
Asunto(s)
Encefalopatías/sangre , Encefalopatías/etiología , Gripe Humana/complicaciones , Interleucina-6/sangre , Niño , Preescolar , Citocinas/sangre , Citocinas/líquido cefalorraquídeo , Femenino , Humanos , Lactante , Interleucina-6/líquido cefalorraquídeo , Masculino , Valor Predictivo de las Pruebas , Pronóstico , Factores de TiempoRESUMEN
Properties of the response functions for a two-dimensional quartic oscillator are studied based on the diagonalization of the Hamiltonian in a large model space. In particular, response functions corresponding to a given momentum transfer are studied for different values of the coupling parameter in the Hamiltonian. The latter controls regular or chaotic nature of the spectra and eigenstates of the system. Fluctuation properties of the energy-strength correlation of the response are investigated. Even when the statistical properties of the system indicate an almost completely chaotic character, there remains a typical structure in the response function similar to that in the regular system. The nature of this structure is studied in some detail.
RESUMEN
In this study, we re-investigated the previously characterized RcsC (sensor His-kinase) --> RcsB (response regulator) phosphorelay system that is involved in the regulation of capsular polysaccharide synthesis in Escherichia coli. The previously proposed model hypothesized the occurrence of a direct phosphotransfer from RcsC to RcsB in response to an unknown external stimulus. As judged from the current general view as to the His --> Asp phosphorelay, this RcsC --> RcsB framework is somewhat puzzling, because RcsC appears to contain both a His-kinase domain and a receiver domain, but not a histidine (His)-containing phosphotransmitter domain (e.g. HPt domain). We thus suspected that an as yet unknown mechanism might be underlying in this particular His --> Asp phosphorelay system. Here, we provide several lines of in vivo and in vitro evidence that a novel and unique His-containing phosphotransmitter (named YojN) is essential for this signalling system. A revised model is proposed in which the multistep RcsC --> YojN --> RcsB phosphorelay is implicated. It was also demonstrated that this complex signalling system is somehow involved in the modulation of a characteristic behaviour of E. coli cells during colony formation on the surface of agar plates, namely swarming.
Asunto(s)
Cápsulas Bacterianas/biosíntesis , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Proteínas de Escherichia coli , Escherichia coli/fisiología , Regulación Bacteriana de la Expresión Génica , Complejos Multienzimáticos , Fosfoproteínas Fosfatasas , Fosfotransferasas , Proteínas Quinasas , Factores de Transcripción/metabolismo , Secuencia de Aminoácidos , Proteínas Bacterianas/química , Medios de Cultivo , Escherichia coli/genética , Datos de Secuencia Molecular , Fosforilación , Plásmidos , Transducción de Señal , Factores de Transcripción/genéticaRESUMEN
His-to-Asp (His-->Asp) phosphorelay mechanisms are presumably involved in propagation of certain environmental stimuli, including phytohormones, in Arabidopsis thaliana. In addition to the previously characterized His-kinases, namely, the ETR1 family of ethylene receptors, CKI1 cytokinin-sensor, and ATHK1 osomo-sensor, this higher plant has three more His-kinases (named AHK2, AHK3, and AHK4). By employing the well-known His-->Asp phosphorelay systems in both the fission yeast and Escherichia coli, evidence is presented showing that the AHK4 His-kinase has an ability to serve as a cytokinin-responsive environmental sensor. Taking advantage of this AHK4-dependent His-->Asp phosphorelay system in E. coli, a phosphorelay interaction between the Arabidopsis His-kinase and histidine-containing phosphotransmitters (AHPs) was also demonstrated for the first time.
Asunto(s)
Arabidopsis/enzimología , Citocininas/metabolismo , Proteínas Quinasas/metabolismo , Proteínas de Arabidopsis , Escherichia coli/metabolismo , Histidina Quinasa , Schizosaccharomyces/metabolismoRESUMEN
Common histidine-to-aspartate (His-to-Asp) phosphorelay signaling systems involve three types of signaling components: a sensor His-kinase, a response regulator, and a histidine-containing phosphotransfer (HPt) protein. In the fission yeast Schizosaccharomyces pombe, two response regulators, Mcs4 and Prr1, have been identified, and it was shown that they are involved in signal transduction in stress responses. Furthermore, Mcs4 and Prr1 appear to be involved in mitotic cell-cycle control and meiosis, respectively. Recently we have identified Spy1 (also known as Mpr1), which encodes an HPt phosphotransmitter, and reported that Spy1, together with Mcs4, plays a role in cell cycle regulation. In this study, we identified and characterized three genes encoding histidine kinase, named Phk1, Phk2, and Phk3 (S. pombe histidine kinase) (also referred as Mak2, Mak3, and Mak1, respectively). Deletion of individual kinase genes has no apparent phenotypes but multiple deletion of these kinases showed the same phenotype of Spyl (Mpr1)-deficient cells, indicating precocious entry into M phase. These results indicated that three histidine kinases that work upstream of the HPt-transmitter, Spy1 (Mpr1), have a redundant function in cell cycle control.
Asunto(s)
Mitosis/genética , Proteínas Quinasas/genética , Proteínas de Schizosaccharomyces pombe , Schizosaccharomyces/enzimología , Transducción de Señal/genética , Secuencia de Aminoácidos , Ácido Aspártico/metabolismo , Ácido Aspártico/fisiología , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/fisiología , Histidina/metabolismo , Histidina/fisiología , Histidina Quinasa , Mitosis/fisiología , Datos de Secuencia Molecular , Mutagénesis , Fosforilación , Proteínas Quinasas/metabolismo , Proteínas Quinasas/fisiología , Schizosaccharomyces/genética , Schizosaccharomyces/fisiología , Homología de Secuencia de Aminoácido , Transducción de Señal/fisiologíaRESUMEN
Schizosaccharomyces pombe expresses a putative transcription factor, named Prr1, which is intriguing in the sense that it contains a bacterial type of phospho-accepting receiver domain, preceded by a mammalian heat shock factor (HSF2)-like DNA-binding domain. The receiver domain is most probably involved in an as yet unidentified histidine-to-aspartate (His-to-Asp) phosphorelay pathway in S. pombe. In this study, the structure, function, and cellular localization of Prr1 were assessed in the context of oxidative stress and His-to-Asp phosphorelay. As the most intriguing result of this study, we found that Prr1 is essential not only for the expression of genes induced by oxidative stress (e.g., ctt1+ and trr1+), but also for the expression of ste11+, which in turn is responsible for the expression of a variety of genes required for sexual development. Accordingly, Prr1-deficient cells are not only hypersensitive to oxidative stress, but also severely defective in conjugation and/or spore formation. These results suggested that the transcription factor Prr1 plays a pivotal role in an as yet unknown signal transduction pathway that is implicated in sexual differentiation. These findings are discussed with special reference to the well-characterized transcription factors Pap1 and Atf1 of S. pombe.
Asunto(s)
Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Proteínas de Schizosaccharomyces pombe , Schizosaccharomyces/genética , Schizosaccharomyces/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Factor de Transcripción Activador 1 , Factores de Transcripción con Cremalleras de Leucina de Carácter Básico , ADN de Hongos/metabolismo , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Genes Fúngicos , Nitrógeno/metabolismo , Estrés Oxidativo , Proteínas Asociadas a Pancreatitis , Schizosaccharomyces/crecimiento & desarrollo , Transducción de SeñalRESUMEN
External glucose stimulates transcription of several genes including ptsG encoding IICB(Glc), a membrane component of the phosphotransferase system (PTS), by relieving the negative regulation of a global repressor Mlc in Escherichia coli. We investigate here how glucose modulates Mlc action. The Mlc-mediated repression is eliminated by a ptsI mutation, while Mlc is constitutively active in a ptsG mutant. We show that IICB(Glc)-FLAG interacts physically with Mlc in crude extracts prepared from cells in which IICB(Glc) is supposed to exist as the non-phosphorylated form. The IICB(Glc)-Mlc interaction is no longer observed when IICB(Glc) is phosphorylated. Exogenously added purified Mlc binds to purified IICB(Glc)-FLAG. We also demonstrate that Mlc is associated with membrane when IICB(Glc) is dephosphorylated while it is in the cytoplasm when IICB(Glc) is phosphorylated or absent. We conclude that IICB(Glc) regulates the cellular localization of Mlc, depending on its phosphorylation state, which is determined by the availability of external glucose. Thus, glucose induces the transcription of Mlc-regulated promoters by sequestering Mlc to the membrane through dephosphorylation of IICB(Glc).
Asunto(s)
Proteínas Bacterianas/metabolismo , Membrana Celular/metabolismo , Proteínas de Escherichia coli , Escherichia coli/metabolismo , Sistema de Fosfotransferasa de Azúcar del Fosfoenolpiruvato/metabolismo , Proteínas Represoras/metabolismo , Escherichia coli/citología , Escherichia coli/efectos de los fármacos , Escherichia coli/enzimología , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Genes Bacterianos/genética , Genes Bacterianos/fisiología , Glucosa/farmacología , Proteínas de la Membrana/metabolismo , Modelos Biológicos , Mutación/genética , Sistema de Fosfotransferasa de Azúcar del Fosfoenolpiruvato/genética , Fosforilación , Fosfotransferasas (Aceptor del Grupo Nitrogenado)/genética , Regiones Promotoras Genéticas/genética , Unión Proteica/efectos de los fármacos , Transporte de Proteínas/efectos de los fármacos , ARN Mensajero/genética , ARN Mensajero/metabolismo , Proteínas Recombinantes de Fusión/metabolismo , Transducción de Señal/efectos de los fármacosRESUMEN
Common histidine-to-aspartate (His-to-Asp) phosphorelay signaling systems involve three types of signaling components: a sensor His kinase, a response regulator, and a histidine-containing phosphotransfer (HPt) protein. In the fission yeast Schizosaccharomyces pombe, two response regulators, Mcs4 and Prr1, have been identified recently, and it was shown that they are involved in the signal transduction implicated in stress responses. Furthermore, Mcs4 appears to be involved in mitotic cell-cycle control. However, neither the HPt phosphotransmitter nor His kinase has been characterized in S. pombe. In this study, we identified a gene encoding an HPt phosphotransmitter, named Spy1 (S. pombe YPD1-like protein). The spy1(+) gene showed an ability to complement a mutational lesion of the Saccharomyces cerevisiae YPD1 gene, which is involved in an osmosensing signal transduction. The result from yeast two-hybrid analysis indicated that Spy1 interacts with Mcs4. To gain insight into the function of Spy1, a series of genetic analyses were conducted. The results provided evidence that Spy1, together with Mcs4, plays a role in regulation of the G(2)/M cell cycle progression. Spy1-deficient cells appear to be precocious in the entry to M phase. In the proposed model, Spy1 modulates Mcs4 in a negative manner, presumably through a direct His-to-Asp phosphorelay, operating upstream of the Sty1 mitogen-activated protein kinase cascade.
Asunto(s)
Proteínas Portadoras/metabolismo , Proteínas de Ciclo Celular/metabolismo , Proteínas Fúngicas/metabolismo , Histidina , Fosfatos/metabolismo , Proteínas Quinasas/metabolismo , Proteínas de Schizosaccharomyces pombe , Schizosaccharomyces/metabolismo , Transducción de Señal , Secuencia de Aminoácidos , Secuencia de Bases , Proteínas Portadoras/genética , Proteínas Portadoras/fisiología , Ciclo Celular , Proteínas de Ciclo Celular/genética , Medios de Cultivo/farmacología , ADN de Hongos , Proteínas Fúngicas/genética , Proteínas Fúngicas/fisiología , Fase G2 , Genes Fúngicos , Peróxido de Hidrógeno/farmacología , Mitosis , Datos de Secuencia Molecular , Fosforilación , Proteínas Quinasas/genética , Schizosaccharomyces/efectos de los fármacos , Schizosaccharomyces/genética , Schizosaccharomyces/crecimiento & desarrolloRESUMEN
SsrA RNA of Escherichia coli, also known as 10Sa RNA or tmRNA, acts both as tRNA and mRNA when ribosomes are paused at the 3' end of an mRNA lacking a stop codon. This process, referred to as trans-translation, leads to the addition of a short peptide tag to the C-terminus of the incomplete nascent polypeptide. The tagged polypeptide is then degraded by C-terminal-specific proteases. Here, we focused on endogenous targets for the SsrA system and on a potential regulatory role of SsrA RNA. First, we show that trans-translation events occur frequently in normally growing E. COLI: cells. More specifically, we report that the lacI mRNA encoding Lac repressor (LacI) is a specific natural target for trans-translation. The binding of LacI to the lac operators results in truncated lacI mRNAs that are, in turn, recognized by the SsrA system. The SsrA-mediated tagging and proteolysis of LacI appears to play a role in cellular adaptation to lactose availability by supporting a rapid induction of lac operon expression.
Asunto(s)
Proteínas Bacterianas/metabolismo , Proteínas de Escherichia coli , Escherichia coli/metabolismo , Operón Lac/genética , Biosíntesis de Proteínas , Procesamiento Proteico-Postraduccional , ARN Bacteriano/metabolismo , Proteínas Represoras/metabolismo , Secuencia de Aminoácidos , Proteínas Bacterianas/genética , Secuencia de Bases , Proteínas Portadoras , Proteína Receptora de AMP Cíclico/genética , Proteína Receptora de AMP Cíclico/metabolismo , Escherichia coli/efectos de los fármacos , Escherichia coli/genética , Escherichia coli/crecimiento & desarrollo , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Isopropil Tiogalactósido/farmacología , Represoras Lac , Datos de Secuencia Molecular , Mutación , Regiones Operadoras Genéticas/genética , Plásmidos/genética , Biosíntesis de Proteínas/efectos de los fármacos , Procesamiento Proteico-Postraduccional/efectos de los fármacos , ARN Bacteriano/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , ARN de Transferencia/genética , ARN de Transferencia/metabolismo , Proteínas Represoras/genética , Activación Transcripcional/efectos de los fármacosRESUMEN
hos3 mutants of the fission yeast Schizosaccharomyces pombe showed the phenotype of high osmolarity sensitivity for growth. An S. pombe strain carrying the hos3-M26 allele cannot form colonies on agar plates containing 2 M glucose, but the parental strain can do so very well, as demonstrated previously. The hos3+ gene was cloned and identified as one that encodes a small protein of 94 amino acids, which shows no sequence similarity to any other proteins in the current databases. A hos3delta strain, which we then constructed, had the phenotype of high osmolarity sensitivity, as in the case of the original hos3-M26 mutant. More interestingly, when these hos- cells were grown in the non-permissive growth condition in the presence of 2 M glucose, we found that unusually many septated cells were accumulated after a prolonged incubation. A multicopy suppressor gene for hos- mutations was also isolated and identified as the dsk1+ gene encoding a protein kinase, which was previously suggested to be implicated in a process of the mitotic regulation of S. pombe. The function of the hos3+ gene is discussed from these results.
Asunto(s)
Clonación Molecular , Schizosaccharomyces/crecimiento & desarrollo , Schizosaccharomyces/genética , Mutación , Concentración Osmolar , Plásmidos , Proteínas RecombinantesRESUMEN
A rare vascular anomaly of the radial artery encountered during elevation of a radial forearm free flap is reported in this paper. We discovered a superficial radial artery which bifurcated from the deep radial artery 4 cm below the antecubital fossa. The blood supply to the proximal radial forearm flap was thought to be from the superficial radial artery, and to the distal forearm flap from both arteries. Ascertaining the course of the radial artery pre- and intraoperatively and careful dissection of the artery are essential to minimise problems of flap transfer.
Asunto(s)
Arteria Radial/anomalías , Colgajos Quirúrgicos/irrigación sanguínea , Adulto , Carcinoma de Células Escamosas/cirugía , Glosectomía/métodos , Mano/irrigación sanguínea , Neoplasias de Cabeza y Cuello/cirugía , Humanos , Masculino , Disección del Cuello/métodos , Faringectomía/métodos , Flujo Sanguíneo RegionalRESUMEN
Live measles virus-specific T helper 1/T helper 2-cytokine productions by peripheral blood mononuclear cells in response to live measles, mumps or varicella virus were measured in 15 patients with subacute sclerosing panencephalitis and 15 controls by enzyme-linked immunosorbent assays. Most patients with subacute sclerosing panencephalitis had a defect in measles virus-specific production of interferon-gamma, one of the T helper 1 type cytokines, despite persistent presence of measles virus, with preserved interleukin-10 (T helper 2 type cytokine) synthesis. Patients with subacute sclerosing panencephalitis were divided into two groups: responders (group A) with significant interferon-gamma production (>20 pg/mL) in response to live measles virus and non-responders (group B) with a little or no interferon-gamma production. Comparison of the clinical courses between groups A and B revealed that all the patients of group A retained receptive function for a long time, while most patients of group B lost the function rapidly (P<0.01). An inverse correlation between interferon-gamma production by peripheral blood mononuclear cells and disease progression suggested that interferon-gamma plays an antiviral role in subacute sclerosing panencephalitis.
Asunto(s)
Interferón gamma/fisiología , Linfocinas/biosíntesis , Vacuna Antisarampión/inmunología , Virus del Sarampión/inmunología , Panencefalitis Esclerosante Subaguda/inmunología , Células TH1/metabolismo , Células Th2/metabolismo , Adolescente , Adulto , Vacuna contra la Varicela/inmunología , Niño , Preescolar , Progresión de la Enfermedad , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Inmunidad Celular , Interferón gamma/biosíntesis , Interferón gamma/deficiencia , Interferón gamma/metabolismo , Interleucinas/biosíntesis , Interleucinas/metabolismo , Linfocinas/metabolismo , Masculino , Virus del Sarampión/patogenicidad , Vacuna contra la Parotiditis/inmunología , Panencefalitis Esclerosante Subaguda/virología , Vacunas Atenuadas/inmunologíaRESUMEN
Measles virus (MV) binding sites of the CD46 gene were sequenced in patients with subacute sclerosing panencephalitis (SSPE) and in controls. There were 3 novel polymorphisms, including C/T at nucleotide position 38 (C/T38), G/A at position 176 (G/A176), and C/T at position 453 (C/T453), at allele frequencies of.97:.03, .99:.01, and.97:.03, respectively. The G/A176 polymorphism causes an Arg/Gln amino acid change within the essential binding sites of MV, whereas the C/A38 polymorphism causes a Ser/Phe change outside the MV binding sites. The C/T453 polymorphism does not produce an amino acid change. Two of the 40 SSPE patients and 2 of the 32 controls had both C/T38 and C/T453 polymorphisms in heterozygous patterns. One control subject, but no SSPE patients, had the G/A176 polymorphism in a heterozygous pattern. Thus, it is not likely that CD46 gene alteration has a role as a host susceptibility factor in the development of SSPE.