RESUMEN
Morphological mutants of Trichoderma reesei were isolated following chemical or insertional mutagenesis. The mutant strains were shown to have reduced viscosity under industrially relevant fermentation conditions and to have maintained high specific productivity of secreted protein. This allowed higher biomass concentration to be maintained during the production phase and, consequently, increased volumetric productivity of secreted protein. The causative mutations were traced to four individual genes (designated sfb3, ssb7, seb1, and mpg1). We showed that two of the morphological mutations could be combined in a single strain to further reduce viscosity and enable a 100% increase in volumetric productivity.
Asunto(s)
Biomasa , Fermentación , Hypocreales/metabolismo , Hypocreales/genética , Industrias , Mutación , ViscosidadAsunto(s)
Brotes de Enfermedades/prevención & control , Subtipo H1N1 del Virus de la Influenza A , Gripe Humana/epidemiología , Complicaciones Infecciosas del Embarazo/epidemiología , Control de Enfermedades Transmisibles/métodos , Transmisión de Enfermedad Infecciosa/prevención & control , Femenino , Salud Global , Humanos , Vacunas contra la Influenza , Gripe Humana/prevención & control , Gripe Humana/transmisión , Gripe Humana/virología , Partería/métodos , Embarazo , Complicaciones Infecciosas del Embarazo/prevención & control , Complicaciones Infecciosas del Embarazo/virologíaRESUMEN
This second in a two-part unit on swine flu looks at infection control measures for nurses. During late spring and early summer, increasing numbers of people became infected with novel swine origin influenza type A virus (influenza A(H1N1)v 2009) and a global pandemic started. Part 1 of this unit explored the biology of influenza viruses and the origins and characteristics of flu pandemics. This part reviews viral transmission, infection prevention and control and pandemic preparedness.
Asunto(s)
Brotes de Enfermedades , Subtipo H1N1 del Virus de la Influenza A , Gripe Humana/epidemiología , Gripe Humana/prevención & control , Infecciones por Orthomyxoviridae/epidemiología , Enfermedades de los Porcinos/epidemiología , Porcinos/virología , Animales , Humanos , Control de Infecciones/métodos , Subtipo H1N1 del Virus de la Influenza A/aislamiento & purificación , Subtipo H1N1 del Virus de la Influenza A/fisiología , Gripe Humana/transmisión , Internet , Factores de Riesgo , Enfermedades de los Porcinos/transmisión , Reino Unido/epidemiología , Organización Mundial de la SaludRESUMEN
This first in a two-part unit on pandemic flu examines background information on influenza viruses and previous pandemics. As the 2009 flu pandemic gathers force, nurses and other healthcare professionals need to understand the scientific background to one of the most common and potentially the most lethal of pandemic infections. This part explores the characteristics of influenzaviruses and reviews the history and context in which human pandemics occur.
Asunto(s)
Brotes de Enfermedades/historia , Gripe Humana/historia , Brotes de Enfermedades/estadística & datos numéricos , Salud Global , Historia del Siglo XX , Humanos , Gripe Humana/epidemiologíaRESUMEN
This is a two-part unit on HIV infection and Aids. Part 1 reviewed the evolving global and national epidemiology of HIV infection and Aids. This second part examines routes of transmission, diagnosis and antiretroviral treatment.
Asunto(s)
Infecciones por VIH/diagnóstico , Infecciones por VIH/transmisión , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/prevención & control , HumanosRESUMEN
This is the first of a two-part unit on HIV and Aids. This part reviews the global epidemiology of the HIV/Aids pandemic.
Asunto(s)
Infecciones por VIH/epidemiología , Salud Global , Humanos , IncidenciaRESUMEN
During the early stages of meiosis in Neurospora, the symmetry of homologous chromosomal regions is carefully evaluated by actively trans-sensing their identity. If a DNA region cannot be detected on the opposite homologous chromosome, then this lack of "sensing" activates meiotic silencing, a post-transcriptional gene silencing-like mechanism that silences all genes in the genome with homology to the loop of unpaired DNA, whether they are paired or unpaired. In this work, we genetically dissected the meiotic trans-sensing step from meiotic silencing by demonstrating that DNA methylation affects sensing without interfering with silencing. We also determined that DNA sequence is an important parameter considered during meiotic trans-sensing. Altogether, these observations assign a previously undescribed role for DNA methylation in meiosis and, on the basis of studies in other systems, we speculate the existence of an intimate connection among meiotic trans-sensing, meiotic silencing, and meiotic recombination.
Asunto(s)
Metilación de ADN , Silenciador del Gen , Meiosis/fisiología , Neurospora/genética , Metilasas de Modificación del ADN/genética , Metilasas de Modificación del ADN/fisiología , Neurospora/fisiologíaAsunto(s)
Metilación de ADN , Neurospora crassa/genética , Interferencia de ARN , ADN de Hongos/metabolismo , Proteínas Fúngicas/metabolismo , Silenciador del Gen , Heterocromatina/metabolismo , Histona Metiltransferasas , N-Metiltransferasa de Histona-Lisina/metabolismo , Mutación , Neurospora crassa/metabolismo , Proteína MetiltransferasasRESUMEN
The presence of unpaired copies of a gene during meiosis triggers silencing of all copies of the gene in the diploid ascus cell of Neurospora. This phenomenon is called meiotic silencing and on the basis of genetic studies appears to be a post-transcriptional gene silencing (PTGS) mechanism. Previously, meiotic silencing was defined to be induced by the presence of a DNA region lacking an identical segment in the homologous chromosome. However, the determinants of unpaired DNA remained a mystery. Using the Ascospore maturation-1 (Asm-1) gene, we defined what needs to be "unpaired" to silence a gene. For efficient silencing, an unpaired region of DNA needs to be of a sufficient size and contain homology to the reporter transcript. The greater the size of the loop and the larger the homology to the reporter transcript, the better the resulting meiotic silencing is. Conversely, regions not containing homology to the transcript, e.g., intergenic regions, did not silence the reporter. Surprisingly, unpaired fragments lacking a canonical promoter silenced the reporter. Additionally, we detected the unpairing-dependent loss of a transcript during meiotic silencing. Our observations further support a PTGS mechanism for meiotic silencing and offer insight into the evolutionary consequences resulting from this novel meiotic checkpoint.
Asunto(s)
ADN/genética , Proteínas Fúngicas/genética , Silenciador del Gen , Neurospora crassa/genética , Factores de Transcripción/genética , Alelos , Cruzamientos Genéticos , ADN/metabolismo , ADN Complementario/metabolismo , Evolución Molecular , Eliminación de Gen , Genes Reporteros , Ligamiento Genético , Genotipo , Histidina/química , Meiosis , Modelos Genéticos , Plásmidos/metabolismo , Reacción en Cadena de la Polimerasa , Regiones Promotoras Genéticas , ARN/química , ARN/metabolismo , Procesamiento Postranscripcional del ARN , ARN Mensajero/metabolismo , Transcripción GenéticaRESUMEN
We demonstrate the involvement of suppressor of meiotic silencing-2 (sms-2(+)), a Neurospora gene coding for an Argonaute-like protein, in meiotic silencing and normal sexual development.
Asunto(s)
Proteínas Fúngicas/genética , Proteínas Fúngicas/fisiología , Silenciador del Gen , Meiosis , Neurospora/genética , Alelos , Genotipo , Modelos Biológicos , Modelos Genéticos , Datos de Secuencia Molecular , FilogeniaRESUMEN
This paper is the second in a two-part series summarising the main findings and conclusions of a review of the roles and responsibilities of infection prevention and control nurses commissioned by the Department of Health. It describes the core work of IPCNs, discusses the strengths and constraints of the current role and makes suggestions for future development.
Asunto(s)
Control de Enfermedades Transmisibles/organización & administración , Enfermería en Salud Comunitaria/organización & administración , Profesionales para Control de Infecciones/organización & administración , Control de Infecciones/organización & administración , Enfermería en Salud Pública/organización & administración , Enfermería en Salud Comunitaria/tendencias , Humanos , Profesionales para Control de Infecciones/tendencias , Enfermería en Salud Pública/tendencias , Reino UnidoRESUMEN
Here, we report the use of the mating type heterokaryon incompatibility system as a counterselection to increase the probability of identifying gene replacements in Neurospora crassa. We compared the frequencies of gene replacements observed among transformants obtained by using plasmids with or without the mat a-1(+) gene (hereby called "Toxic Gene") placed adjacent to disruption cassettes. On an average, we were 20x more likely to identify a correct gene replacement by incorporating the toxic gene in our constructs. Using this strategy, we constructed strains containing a deletion of the inl (1L-myo-inositol-1-phosphate synthase) gene. Finally, we demonstrated that we were able to remove the transformation marker (the hygromycin B phosphotransferase- thymidine kinase gene fusion [hph(+)::tk(+)]) from the genome by using a strategy similar to the "URA-blaster" strategy used in yeast, which we call "tk-blaster."