7 research outputs found

    Analysis of the CYC1 Promoter in Candida Albicans

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    Scientists are considering two factors that may be important in the pathogenesis of C. albicans\u27, it\u27s capability to morph from yeast to hyphal phase, and its differences in colony morphology, cell shape, cell surface and cell permeability. (5) Unfortunately, unlike the bacteria, yeasts do not yet have proven virulence factors. However, science is suggesting that some of the major factors which contribute to the virulence of Candida are its ability to form hyphae, its ability to resist phagocytosis, its ability to adhere to epithelial cell surfaces, its ability to grow well at 37 degrees Celsius, and its ability to secrete acid proteinase. (5) Recent studies are looking into an iC3b receptor that may also influence virulence. (5) Unfortunately, factors like nutritional requirements complicate the virulence determinations. (3) Molecular Koch\u27s postulates are now being considered as a way to study virulence in yeasts. (3) Because of the many problems that arise with C. albicans, scientists are taking steps to increase the development of its genetics. (5

    Qualitative and Quantitative Assessment of the 'Dangerous Activities' Categories Defined by the CISSM Controlling Dangerous Pathogens Project

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    The Controlling Dangerous Pathogens Project of the Center for International Security Studies at Maryland (CISSM) outlines a prototype oversight system for ongoing microbiological research to control its possible misapplication. This so-called Biological Research Security System (BRSS) foresees the creation of regional, national, and international oversight bodies that review, approve, or reject those proposed microbiological research projects that would fit three BRSS-defined categories: Potentially Dangerous Activities (PDA), Moderately Dangerous Activities (MDA), and Extremely Dangerous Activities (EDA). It is the objective of this working paper to assess these categories qualitatively and quantitatively. To do so, published US research of the years 2000-present (early- to mid-2005) will be screened for science reports that would have fallen under the proposed oversight system had it existed already. Qualitatively, these selective reports will be sorted according to the subcategories of each individual Dangerous Activity, broken down by microbiological agent, and year. Quantitatively, institutes and researchers, which conducted research that would have fallen under review by BRSS, will be listed according to category and year. Taken together, the results of this survey will give an overview of the number of research projects, institutes, and researchers that would have been affected had the new proposed system existed, and thus should allow estimating the potential impact of BRSS on US microbiological academic and industrial research in the future. Furthermore, this working paper might aid refining the proposed system

    Die Rolle des RNA-bindenden Proteins Rrm4 während des polaren Wachstums von Ustilago maydis

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    Polarität und funktionelle Kompartimentierung sind grundlegende Konzepte eukaryontischer Zellen. Der aktive Transport von Vesikeln, Proteinen und mRNA entlang des Zytoskeletts ist ein wichtiger Bestandteil bei der Etablierung und Aufrechterhaltung einer zellulären Polaritätsachse. In Ustilago maydis ist das RNA-bindende Protein Rrm4 am Mikrotubuli-abhängigen mRNA-Transport spezifischer Transkripte während der Filamentbildung beteiligt. Dieser Transportprozess ist wichtig für das polare, filamentöse Wachstum und die Pathogenität des Pilzes. Der Verlust von Rrm4 führt zu erhöhtem bipolarem Wachstum und einer gedrungenen Filamentmorphologie. Die eigentliche zellbiologische Funktion dieses mRNA-Langstreckentransportes ist noch weitestgehend ungeklärt. In dieser Arbeit wurden, basierend auf einer differentiellen Proteom-Analyse zwischen Wildtyp- und rrm4-Filamenten, sieben differentiell exprimierte Proteine identifiziert. Ihre funktionelle Analyse spricht für eine Beteiligung des Rrm4-abhängigen mRNA-Transportes an der Sekretion eines Zellwand-abbauendem Enzyms und der Biogenese von Mitochondrien. Die Deletion von rrm4 resultierte in einer intrazellulären Akkumulation der Endochitinase Cts1, wobei weder die subapikale Lokalisation noch die Aktivität der Cts1 beeinträchtigt wurde. Zudem bestätigte eine FISH-Analyse die cts1-mRNA als direktes Ziel-Transkript von Rrm4 und die Anreicherung der Cts1 konnte auf einen Defekt in der Sekretion von rrm4-Filamente zurückgeführt werden. Des Weiteren wurde anhand von drei differentiell exprimierten Mitochondrienproteinen in rrm4-Filamenten eine Dysfunktion identifiziert, welche sich in einer gesteigerten mitochondriellen Superoxid-Produktion äußerte. Um weitere Einblicke in den mRNA-Transport zu gewinnen, wurde eine Lokalisationsstudie des Poly-(A)-bindende Proteins (Pab1) durchgeführt. In Wildtyp-Filamenten ko-lokalisierte Pab1 mit Rrm4, in vivo, in pendelnden Partikeln. Interessanterweise wurden in rrm4-Filamenten keine sich bewegenden Pab1-Partikel detektiert. Folglich bildet Rrm4 die Haupttransporteinheit des mRNA-Langstreckentransports in Filamenten. Dementsprechend reguliert der Rrm4-abhängige mRNA-Transport apikale Sekretionsprozesse und scheint zusätzlich die gleichmäßige Versorgung des Protein-Imports in die Mitochondrien zu steuern

    Estudio del efecto de quitinasas recombinantes como potenciadoras de la actividad insecticida de un aislamiento de Beauveria bassiana para el control de Diatraea saccharalis

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    Las quitinasas son enzimas hidrolíticas provenientes de diferentes fuentes biológicas. En virus y hongos entomopatógenos, las quitinasas han sido reportadas como importantes factores de virulencia que cortan la estructura de la quitina presente en las dos principales barreras de protección de los insectos: la cutícula y la matriz peritrófica del intestino medio. Con el fin de estudiar el efecto de quitinasas recombinantes en la actividad insecticida de Beauveria bassiana sobre larvas de Diatraea saccharalis, en este trabajo se clonaron y expresaron en E. coli los marcos abiertos de lectura que codifican para las quitinasas Chit37 y Chit2A provenientes de los aislamientos colombianos Bv062 de B. bassiana y VG008 del granulovirus de Spodoptera frugiperda, respectivamente. La quitinasa fúngica recombinante (rChit37) purificada a partir de la fracción soluble del cultivo de células BL21-DE3, presentó actividad quitinolítica dual de tipo quitobiosidasa y endoquitinasa (EC 3.2.2.14) bajo condiciones óptimas de 45°C y pH 5.0. La rChit37 purificada potenció la actividad insecticida de B. bassiana sobre larvas de segundo instar de D. saccharalis; cuando se adicionó a una concentración de 300 µg/mL en una suspensión de 1x106 conidios/mL, se evidenció una reducción de 46% y 68% en los tiempos letales (TL50 y TL90) y un incremento de la eficacia en 61%. La proteína viral recombinante (rChit2A) presentó un dominio de unión a quitina en su secuencia, sin embargo, no se observó dominio catalítico, lo que se corroboró con la ausencia de actividad enzimática. Los hallazgos de este trabajo proveen una prueba concepto inicial para el estudio de quitinasas recombinantes en el desarrollo de futuras estrategias de potenciación de hongos entomopatógenos con potencial en el control biológico.Chitinases are hydrolytic enzymes from different biological sources. In viruses and entomopathogenic fungi, chitinases have been reported as important virulence factors that cleave the chitin structure present in the two main protective barriers of insects: the cuticle and the peritrophic matrix of the midgut. In the present work, the open reading frames encoding chitinases Chit37 and Chit2A in the Colombian isolates Bv062 and VG008 of B. bassiana and the granulovirus of Spodoptera frugiperda, respectively, were cloned and expressed in E. coli to study the effect of recombinant chitinases on the insecticidal activity of Beauveria bassiana on larvae of Diatraea saccharalis. The recombinant fungal chitinase (rChit37) purified from the soluble fraction of the BL21-DE3 cell culture, displayed dual chitinolytic activity of the quitobiosidase and endochitinase types (EC 3.2.2.14) under optimal conditions of 45°C and pH 5.0. The purified rChit37 enhanced the insecticidal activity of B. bassiana on second instar larvae of D. saccharalis; a reduction of 46% and 68% in lethal times (TL50 and TL90) and an increase in efficacy by 61% was observed when added at a 300 μg/mL concentration in a suspension of 1x106 conidia/mL. The recombinant viral protein (rChit2A) showed a chitin binding domain in its sequence, however, no catalytic domain was observed, which was in agreement with the lack of enzymatic activity. The findings of this work provide an initial proof of concept for the study of recombinant chitinases in the development of future strategies of entomopathogenic fungal enhancement for biological control.Corporación Colombiana de investigación agropecuaria AGROSAVIAMaestrí
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