Individual chitin synthase enzymes synthesize microfibrils of differing structure at specific locations in the Candida albicans cell wall

The shape and integrity of fungal cells is dependent on the skeletal polysaccharides in their cell walls of which β(1,3)-glucan and chitin are of principle importance. The human pathogenic fungus Candida albicans has four genes, CHS1, CHS2, CHS3 and CHS8, which encode chitin synthase isoenzymes with different biochemical properties and physiological functions. Analysis of the morphology of chitin in cell wall ghosts revealed two distinct forms of chitin microfibrils: short microcrystalline rodlets that comprised the bulk of the cell wall; and a network of longer interlaced microfibrils in the bud scars and primary septa. Analysis of chitin ghosts of chs mutant strains by shadow-cast transmission electron microscopy showed that the long-chitin microfibrils were absent in chs8 mutants and the short-chitin rodlets were absent in chs3 mutants. The inferred site of chitin microfibril synthesis of these Chs enzymes was corroborated by their localization determined in Chsp–YFP-expressing strains. These results suggest that Chs8p synthesizes the long-chitin microfibrils, and Chs3p synthesizes the short-chitin rodlets at the same cellular location. Therefore the architecture of the chitin skeleton of C. albicans is shaped by the action of more than one chitin synthase at the site of cell wall synthesis

Multidisciplinary exercises: coordination practices and applications from fundamental to applied subjects in agriculture engineering

This activity is carried out in the framework of an innovation project, whose main objective is to coordinate mathematical, physical and engineering contents for a transversal educational path focused on mechatronics, automated control and information and communication technologies. In such sense one important task in this project is the elaboration of practices and joint applications which will be proposed to the students in successive matters upon different points of view: “Common Practices”. Through this activity students will be guided to establish relationships between their scientific basic training and their technological formation. The students will work on the same example during different academic years and semesters using common materials and working spaces. The whole experience will be displayed in Moodle, a virtual learning environment. A preliminary proposal of “Common practice” is presented in this paper as one example: “Design and Analysis of Suspensions Systems for Stabilizing the Roll of Spray Booms”. In this example students of different academic levels are asked to solve the complexity of the problem along different subjects: Field measurements (analysis of variability on chemical applications using a spray boom) will be realized in the Agriculture Machinery topic - equivalent to 4.5 ECTS -. Analytical models for the analysis of different suspension systems in the Mechanics and Mechanisms topic -4.5 ECTS -. In Agriculture Applied Electronics – 2.5 ECTS – sensors and actuators will be studied to design controllers. Control strategies for damping the resonance frequency of the suspension will be studied in Process Simulation and Optimization – 3.5 ECTS –. And, finally, the design and development of a vehicle with a spray bar and the corresponding suspension systems will be done in the Robotics topic – 7 ECTS –

Actas de la 1. reunion nacional de geomorfologia

Available from Centro de Informacion y Documentacion Cientifica CINDOC. Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai

RcoA has pleiotropic effects on aspergillus nidulans cellular development

The definitive version is available at www.blackwell-synergy.comAspergillus nidulans rcoA encodes a member of the WD repeat family of proteins. The RcoA protein shares sequence similarity with other members of this protein family, including the Saccharomyces cerevisiae Tup1p and Neurospora crassa RCO1. Tup1p is involved in negative regulation of an array of functions including carbon catabolite repression. RCO1 functions in regulating pleiotropic developmental processes, but not carbon catabolite repression. In A. nidulans, deletion of rcoA (DrcoA), a recessive mutation, resulted in gross defects in vegetative growth, asexual spore production and sterigmatocystin (ST) biosynthesis. Expression of the asexual and ST pathway-specific regulatory genes, brlA and aflR, respectively, but not the signal transduction genes (i.e. flbA, fluG or fadA) regulating brlA and aflR expression was delayed (brlA) or eliminated (aflR) in a DrcoA strain. Overexpression of aflR in a DrcoA strain could not rescue normal expression of downstream targets of AflR. CreAdependent carbon catabolite repression of starch and ethanol utilization was only weakly affected in a DrcoA strain. The strong role of RcoA in development, vegetative growth and ST production, compared with a relatively weak role in carbon catabolite repression, is similar to the role of RCO1 in N. crassa.Julie Hicks, Robin A. Lockington, Joseph Strauss, Daniel Dieringer, Christian P. Kubicek, Joan Kelly and Nancy Kelle