RESUMO
Parsley cells recognize the fungal plant pathogen Phytophthora sojae through a plasma membrane receptor. A pathogen-derived oligopeptide elicitor binds to this receptor and thereby stimulates a multicomponent defense response through sequential activation of ion channels and an oxidative burst. An elicitor-responsive mitogen-activated protein (MAP) kinase was identified that acts downstream of the ion channels but independently or upstream of the oxidative burst. Upon receptor-mediated activation, the MAP kinase is translocated to the nucleus where it might interact with transcription factors that induce expression of defense genes.
Assuntos
Proteínas Quinases Dependentes de Cálcio-Calmodulina/metabolismo , Proteínas Fúngicas/farmacologia , Glicoproteínas de Membrana/farmacologia , Plantas/enzimologia , Sequência de Aminoácidos , Anfotericina B/farmacologia , Antracenos/farmacologia , Proteínas Quinases Dependentes de Cálcio-Calmodulina/química , Proteínas Quinases Dependentes de Cálcio-Calmodulina/genética , Núcleo Celular/enzimologia , Células Cultivadas , Ativação Enzimática , Canais Iônicos/efeitos dos fármacos , Canais Iônicos/metabolismo , Dados de Sequência Molecular , Oniocompostos/farmacologia , Fragmentos de Peptídeos/farmacologia , Fosforilação , Phytophthora/metabolismo , Plantas/genética , Plantas/microbiologia , Explosão Respiratória/efeitos dos fármacosRESUMO
Recent advancements in the use of microbial cells for scalable production of industrial enzymes encourage exploring new environments for efficient microbial cell factories (MCFs). Here, through a comparison study, ten newly sequenced Bacillus species, isolated from the Rabigh Harbor Lagoon on the Red Sea shoreline, were evaluated for their potential use as MCFs. Phylogenetic analysis of 40 representative genomes with phylogenetic relevance, including the ten Red Sea species, showed that the Red Sea species come from several colonization events and are not the result of a single colonization followed by speciation. Moreover, clustering reactions in reconstruct metabolic networks of these Bacillus species revealed that three metabolic clades do not fit the phylogenetic tree, a sign of convergent evolution of the metabolism of these species in response to special environmental adaptation. We further showed Red Sea strains Bacillus paralicheniformis (Bac48) and B. halosaccharovorans (Bac94) had twice as much secreted proteins than the model strain B. subtilis 168. Also, Bac94 was enriched with genes associated with the Tat and Sec protein secretion system and Bac48 has a hybrid PKS/NRPS cluster that is part of a horizontally transferred genomic region. These properties collectively hint towards the potential use of Red Sea Bacillus as efficient protein secreting microbial hosts, and that this characteristic of these strains may be a consequence of the unique ecological features of the isolation environment.
Assuntos
Bacillus/genética , Genoma Bacteriano , Redes e Vias Metabólicas , Filogenia , Organismos Aquáticos , Genômica , Oceano ÍndicoRESUMO
Mechanical injury in plants induces responses that are involved not only in healing but also in defense against a potential pathogen. To understand the intracellular signaling mechanism of wounding, we have investigated the involvement of protein kinases. Using specific antibodies, we showed that wounding alfalfa leaves specifically induces the transient activation of the p44MMK4 kinase, which belongs to the family of mitogen-activated protein kinases. Whereas activation of the MMK4 pathway is a post-translational process and was not blocked by [alpha]-amanitin and cycloheximide, inactivation depends on de novo transcription and translation of a protein factor(s). After wound-induced activation, the MMK4 pathway was subject to a refractory period of 25 min, during which time restimulation was not possible, indicating that the inactivation mechanism is only transiently active. After activation of the p44MMK4 kinase by wounding, transcript levels of the MMK4 gene increased, suggesting that the MMK4 gene may be a direct target of the MMK4 pathway. In contrast, transcripts of the wound-inducible MsWIP gene, encoding a putative proteinase inhibitor, were detected only several hours after wounding. Abscisic acid, methyl jasmonic acid, and electrical activity are known to mediate wound signaling in plants. However, none of these factors was able to activate the p44MMK4 kinase in the absence of wounding, suggesting that the MMK4 pathway acts independently of these signals.
RESUMO
Interferon was measured at different intervals after the iv, sc, and im application of exogenous human leukocyte interferon to patients with various virus diseases or neoplasms. Interferon injected iv into patients had a half-life of about 15 minutes in the 1st hour and of about 90 minutes in the next 3 hours. Six hours after iv injection of 30 million U, no serum interferon was detectable. With a continuous iv infusion, a relatively high serum interferon level was reached. By the im administration of 1 million U interferon, a peak level of serum interferon (mean value 107 U/ml serum) occurred after 2 hours and was fairly stable for about 6 hours. Twenty-four hours after im application, a low level of serum interferon was still detectable. Similar results were found after sc interferon injections. In a patient with subacute sclerosing panencephalitis, no interferon was found in the cerebrospinal fluid at the time of the highest serum interferon level and 24 hours after two im interferon injections. Only minimal side reactions resulted from sc and im interferon injections. In one patient, a shock reaction occurred after iv application. For therapeutic trials, about 1 million U exogenous human interferon should be injected twice daily im or sc.
Assuntos
Interferons/metabolismo , Encefalite/líquido cefalorraquidiano , Meia-Vida , Humanos , Injeções Intramusculares , Injeções Intravenosas , Injeções Subcutâneas , Interferons/administração & dosagem , Interferons/sangue , Interferons/líquido cefalorraquidiano , Leucócitos , Neoplasias/metabolismo , Fatores de Tempo , Viroses/metabolismoRESUMO
Plant growth is severely affected by hyper-osmotic salt conditions. Although a number of salt-induced genes have been isolated, the sensing and signal transduction of salt stress is little understood. We provide evidence that alfalfa cells have two osmo-sensing protein kinase pathways that are able to distinguish between moderate and extreme hyper-osmotic conditions. A 46 kDa protein kinase was found to be activated by elevated salt concentrations (above 125 mM NaCl). In contrast, at high salt concentrations (above 750 mM NaCl), a 38 kDa protein kinase, but not the 46 kDa kinase, became activated. By biochemical and immunological analysis, the 46 kDa kinase was identified as SIMK, a member of the family of MAPKs (mitogen-activated protein kinases). SIMK is not only activated by NaCl, but also by KCl and sorbitol, indicating that the SIMK pathway is involved in mediating general hyper-osmotic conditions. Salt stress induces rapid but transient activation of SIMK, showing maximal activity between 8 and 16 min before slow inactivation. When inactive, most mammalian and yeast MAPKs are cytoplasmic but undergo nuclear transloca- tion upon activation. By contrast, SIMK was found to be a constitutively nuclear protein and the activity of the kinase was not correlated with changes in its intra-cellular compartmentation, suggesting an intra-nuclear mechanism for the regulation of SIMK activity.
RESUMO
Mitogen-activated protein kinases (MAPKs) are important signaling tools in all eukaryotes, and function in mediating an enormous variety of external signals to appropriate cellular responses. MAPK pathways have been studied extensively in yeast and mammalian cells, and a large body of knowledge on their functioning has accumulated, which is summarized briefly. Plant MAPK pathways have attracted increasing interest, resulting in the isolation of a large number of different components of MAPK cascades. Studies on the functions of these components have revealed that MAPKs play important roles in the response to a broad variety of stresses, as well as in the signaling of most plant hormones and in developmental processes. Finally, the involvement of various plant phosphatases in the inactivation of MAPKs is discussed.
Assuntos
Sistema de Sinalização das MAP Quinases/fisiologia , Células Vegetais , Plantas/metabolismo , Ciclo Celular/fisiologia , Células Eucarióticas/citologia , Células Eucarióticas/metabolismo , Regulação da Expressão Gênica de Plantas/fisiologia , MAP Quinase Quinase Quinases/metabolismo , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Filogenia , Doenças das Plantas/genética , Reguladores de Crescimento de Plantas/metabolismo , Estrutura Terciária de Proteína/fisiologia , Cicatrização/fisiologiaRESUMO
To study a cyclin-dependent kinase (CDK) from alfalfa (Medicago sativa L.), an antibody was raised against the C-terminal 16 amino acids of the protein cdc2aMs. The cdc2Ms protein was immunopurified with this antibody and its histone kinase activity was measured. The cdc2Ms kinase is activated at the G1/S transition when phosphate-starved cells from the G0 phase re-enter the cell cycle and remain active as cells transit the S, G2, and M phases, indicating that the same CDK regulates all of these phases in alfalfa. In contrast, when cdc2Ms kinase was purified by binding to p13suc1, it was active only in the G2 and M phases. In immunoblots the C-terminal antibody detected an equal amount of the cdc2Ms protein in the cytoplasm and in the nucleus. By indirect immunofluorescence, however, the cytoplasmic form of cdc2Ms could not be found in the S phase of the cells, indicating that the epitope for the cdc2 antibody is not accessible. Binding of putative inhibitor proteins to cdc2 was shown by inactivation of purified plant CDK when cell extracts were added. Furthermore, purified CDK inhibitors, such as the mouse p27kip1 and the yeast p40sic1, blocked the purified plant CDK activity.
RESUMO
A cerebellar ganglioglioma was surgically removed from a two-year old boy, who had developed manifestations of increased intracranial pressure and cerebellar symptoms. At surgery, the tumor presented as a firm nodular mass displacing the cerebellar cortex. By light microscopy, its architecture differed distinctly from that of hamartomatous diffuse hypertrophy of the cerebellar cortex (Lhermitte-Duclos' disease). Mature ganglion cells were grouped in clusters and linked by thick bundles of nerve cell processes. Nerve cells and processes were enmeshed in a rich network of fibrillary connective tissue. Electron microscopy disclosed typical neuronal perikarya as well as numerous asymmetric chemical synapses. The bulk of the tumor consisted of tightly grouped, (non-myelinated) nerve cell processes arranged in parallel. One of the most prominent features of the tumor consisted of numerous dilatations of these processes. The largest ones contained microfilaments, while the smaller ones were entirely filled with dense bodies (most probably derived from degenerating mitochondria). Only scattered dense core vesicles were seen, which probably did not represent neurosecretory granules. A second cell type consisted probably of astrocytes. Most neuroepithelial cell processes could not be identified with certainty as being of either neuronal or glial origin. A third cell type consisted of numerous slender cells which were probably mesenchymal. They were surrounded by a network of basement membrane which extended between the surrounding nerve cell processes.
Assuntos
Neoplasias Cerebelares/ultraestrutura , Neuroblastoma/ultraestrutura , Neoplasias Cerebelares/cirurgia , Cerebelo/ultraestrutura , Grânulos Citoplasmáticos/ultraestrutura , Humanos , Corpos de Inclusão/ultraestrutura , Lactente , Masculino , Neuroblastoma/cirurgia , Neurônios/ultraestruturaRESUMO
The producer cells of interferon were studied in human leucocyte cultures stimulated by a variety of stimulants, including phytohemagglutinin (PHA), pokeweed mitogen (PWM), Corynebacterium parvum (CP) and Herpes Simplex Virus (HSV). When the cells were fractionated by the use of neuraminidase-treated sheep red blood cells (SRBC), the T cell population responded with interferon production to PHA and PWM but not to CP or HSV. However, the non-T population showed a vigorous response to the latter two stimuli. In contrast, nylon column eluate cells enriched for T cells responded well to CP and HSV with production of interferon. To resolve these contradictory data, we have used combinations of techniques. Nylon column eluate cells were further separated by SRBC and it was found that the nylon non-adherent rosetting cell did not produce interferon in response to HSV or CP whereas the nylon-nonadherent non-rosetting cell did. In additional experiments more elaborate techniques were used. Leucocytes were treated by plastic adherence and iron filings, passed over a nylon column and subsequently over an Ig-anti-Ig column, and then rosetted with SRBC. Again only the non-rosetting population produced interferon. In parallel experiments the capacity of the different cell populations to lyse three types of target cells in a chromium release assay as a test for "natural killer" (NK) cell activity was investigated. There was some correlation between interferon production and NK cell activity. Thus, our data indicate that interferon is produced by non-T, non-B cells, possibly by cells related to NK cells.
Assuntos
Interferons/biossíntese , Células Matadoras Naturais/imunologia , Linfócitos/imunologia , Propionibacterium acnes/imunologia , Células Cultivadas , Humanos , Células Matadoras Naturais/microbiologia , Células Matadoras Naturais/fisiologia , Linfócitos/microbiologia , Linfócitos/fisiologia , Formação de Roseta , Simplexvirus/imunologia , Linfócitos T/metabolismo , Linfócitos T/microbiologia , Linfócitos T/fisiologiaRESUMO
The tetracycline resistance plasmid pCF10 represents a class of unique mobile genetic elements of the bacterial genus Enterococcus, whose conjugative transfer functions are inducible by peptide sex pheromones excreted by potential recipient cells. These plasmids play a significant role in the dissemination of virulence and antibiotic resistance genes among the enterococci, which have become major nosocomial pathogens. Pheromone response by plasmid-carrying donor cells involves specific import of the peptide signal molecule, and subsequent interaction of the signal with one or more intracellular regulatory gene products. The pheromones are chromosomally encoded hydrophobic octa- or hepta-peptides, and different families of homologous plasmids encode the ability to respond to each pheromone. Among the four pheromone-responsive plasmids that have been characterized in some detail, there is considerable conservation in the genes encoding pheromone sensing and regulatory functions, and the peptides themselves show considerable similarity. In spite of this, there is extremely high specificity of response to each peptide, with virtually no "cross-induction" of transfer of non-cognate pheromone plasmids by the pheromones. This communication reviews the evidence for this specificity and discusses current molecular and genetic approaches to defining the basis for specificity.
Assuntos
Enterococcus faecalis/metabolismo , Oligopeptídeos/genética , Oligopeptídeos/farmacocinética , Feromônios/genética , Feromônios/farmacocinética , Plasmídeos/genética , Plasmídeos/metabolismo , Sequência de Aminoácidos/fisiologia , Sítios de Ligação/fisiologia , Transporte Biológico/fisiologia , Enterococcus faecalis/genética , Dados de Sequência Molecular , Sensibilidade e Especificidade , Resistência a Tetraciclina/genética , Resistência a Tetraciclina/fisiologiaRESUMO
The purpose of this study was to compare side-by-side two different titanium screw-type implants in the maxillae of miniature pigs. The test implants had a machined and acid-etched surface (Osseotite) whereas the control implants were sandblasted and acid-etched (SLA). After 4, 8, and 12 weeks of healing, removal torque testing was performed to evaluate the shear strength of the bone-implant interface for both implant types. The results demonstrated significant differences between both implant types (P < .01). Osseotite implants revealed mean removal torque values (RTV) of 62.5 Ncm at 4 weeks, 87.6 Ncm at 8 weeks, and 95.7 Ncm at 12 weeks of healing. In contrast, the SLA implants demonstrated mean RTV of 109.6 Ncm, 196.7 Ncm, and 186.8 Ncm at corresponding healing periods. The mean RTV for SLA implants was 75% to 125% higher than for Osseotite implants up to 3 months of healing.
Assuntos
Implantes Dentários , Osseointegração , Titânio , Análise de Variância , Animais , Implantação Dentária Endóssea , Planejamento de Prótese Dentária , Análise do Estresse Dentário , Análise de Falha de Equipamento , Maxila , Microscopia Eletrônica de Varredura , Estatísticas não Paramétricas , Propriedades de Superfície , Suínos , Porco Miniatura , TorqueRESUMO
The plant Artemisia annua L. (Asteraceae) is listed in the Chinese pharmacopoeia as a remedy for various fevers including malaria, and contains the well-established antimalarial compound artemisinin. In this study, a hybrid form of A. annua was successfully cultivated in Central Africa. The aerial parts of the plant contained 0.63-0.70% artemisinin per dry weight, and approximately 40% of this artemisinin could be extracted by simple tea preparation methods. Five malaria patients who were treated with A. annua tea showed a rapid disappearance of parasitaemia within 2-4 days. An additional trial with 48 malaria patients showed a disappearance of parasitaemia in 44 patients (92%) within 4 days. Both trials showed a marked improvement of symptoms. In our opinion, these results justify further examinations of the antimalarial effect of A. annua preparations.
Assuntos
Artemisia/química , Artemisininas , Malária/terapia , Plantas Medicinais , Humanos , Lactonas/uso terapêutico , Sesquiterpenos/uso terapêutico , Chá , Clima TropicalRESUMO
A new surgical technique for localized ridge augmentation prior to the placement of dental implants has been developed. The technique is based on the principle of guided bone regeneration utilizing barrier membranes. In the present article, the currently used surgical procedure is presented through two case reports. In addition, the different aspects of the surgical technique needed to achieve a predictable success are discussed.
Assuntos
Aumento do Rebordo Alveolar/métodos , Regeneração Óssea , Implantação Dentária Endóssea/métodos , Regeneração Tecidual Guiada Periodontal , Maxila/cirurgia , Adolescente , Adulto , Humanos , Masculino , Membranas Artificiais , Politetrafluoretileno , Retalhos CirúrgicosRESUMO
The principle of guided bone regeneration can be applied for localized ridge augmentation in a staged approach. The surgical procedure for the mandible is presented through three case reports. Incision technique and flap design, utilization of autogenous bone grafts as a membrane-supporting device and osteoconductive scaffold, proper placement of barrier membranes and their stabilization with miniscrews, and wound closure are all emphasized. Furthermore, factors essential for achieving predictable results with barrier membranes for localized ridge augmentation and the benefits of combining barrier membranes with autogenous bone grafts are discussed.
Assuntos
Aumento do Rebordo Alveolar/métodos , Regeneração Óssea , Regeneração Tecidual Guiada Periodontal , Mandíbula/cirurgia , Transplante Ósseo/métodos , Implantação Dentária Endóssea/métodos , Feminino , Humanos , Pessoa de Meia-Idade , Planejamento de Assistência ao Paciente , Complicações Pós-Operatórias/prevenção & controle , Retalhos Cirúrgicos , Fatores de TempoRESUMO
The orthograde colon lavage, suggested by Crapp, is a new method for the preoperative preparation of the colon. On the day prior to surgery, the sitting patient receives for 4 h through a stomach probe, 101 of physiological saline solution warmed up to 37 degrees C. The result is a complete evacuation of the bowel. If a bactericidal antibiotic with a broad spectrum of activity (neomycin) is added, the suppression of the microflora amounts to 92%. The regeneration of the intestinal flora could be observed after a few days. A complete evacuation of the colon is guaranteed by this procedure, so that all operations can be performed under optimal conditions. From the clinical as well as from the microbiological point of view this method is without any risk. -- The orthograde colon lavage is indicated in every case of colon, rectum and anal surgery, but it is contraindicated in patients with highly stenosing tumors.