Search results for "WALL"

The cell wall structure: developments in diagnosis and treatment of candidiasis

1998

Candidiasis are among the fungal infections the most difficult to diagnose and treat. Research focused on specific fungal components which are absent in the host, such as the cell wall has lead to a better understanding of Candida albicans pathogenicity and clinical impact. The cell wall is responsible for antigenic expression and primary interaction with the host. It is composed mainly of b-glucans, chitin and mannoproteins, which account for the rigidity of the wall and for the fungal morphology. Of these components, mannoproteins might carry a “morphogenetic code” which might modulate the molecular architecture of the cell wall. The features of specific cell wall proteins as part of buil…

Saccharomyces cerevisiae Rds2 transcription factor involvement in cell wall composition and architecture

2008

Although the cell wall is very important in yeasts, relatively little is known about the relationship between its structure and function. In Saccharomyces cerevisiae, a family of 55 transcription factor proteins unique to fungi, so-called zinc cluster proteins, has been described. Of these, Rds2 has been identified as an activator/inhibitor of gluconeogenesis. However, previous studies have pointed out additional roles for this protein, specifically, in the modulation of cell-wall architecture and drug sensitivity. In this work, evidence regarding the role of Rds2 as a regulator of cell-wall architecture and composition is presented based on phenotypical analysis of the cell walls prepared …

The Cell Surface of <i>Candida albicans</i> during Morphogenesis

2000

Autolysis of Yeasts

2011

Autolysis of yeast cells occurs after they have completed their life cycle and entered the death phase. It is characterized by a loss of cell membrane permeability, alteration of cell wall porosity, hydrolysis of cellular macromolecules by endogenous enzymes, and subsequent leakage of the breakdown products into the extracellular environment. Although a naturally occurring event, autolysis can be induced by exposing yeasts to elevated temperatures (40–60 °C), organic solvents, or detergents. Yeast autolysis occurs in many foods and beverages, where it may affect their sensory quality and commercial acceptability.

Proteinaceous Surface Layers ofArchaea: Ultrastructure and Biochemistry

2014

The cell walls of the Archaea are composed of different polymers such as glutaminylglycan, heterosaccharide, methanochondroitin, pseudomurein, protein, glycoprotein, or glycocalyx. The S-layer glycoprotein of Halobacterium salinarum was the first glycoprotein discovered in bacteria and archaea. Initially, the novel cell wall structures were viewed as curiosities, and their taxonomic significance was not realized until the concept of the Archaea was published. At this time, the results of cell wall studies supported the new view of the phylogeny of the Bacteria and Archaea. Many archaea possess proteinaceous surface layers (S layers), which form two-dimensional regular arrays. The chemical s…

Biogenesis of the Yeast Cell Wall

1984

Yeast cells are covered by a rigid structure that protects the protoplast from osmotic changes and gives the characteristic shape to the cell. Studies on the composition of the wall of several species of yeast and other fungi have shown that they contain mainly polysaccharides with minor amounts of other materials. A completely rigid and continuous wall, nevertheless, would render growth impossible because cell extension would be restricted, so that an equilibrium must exist between softening (partial degradation) of wall and incorporation of new material into free ends of the polymers. From these considerations, it seems clear that the walls must be structurally and enzymatically a complex…

Zur Biosynthese der Cellulose

1966

Biogenesis of the Fungal Cell Wall

1994

Cell walls play essential roles in growth, development, and in interactions of fungi with the environment and with other cells. Besides its primary protective role in shielding the cell against osmotic, chemical, and biological harm, the wall is involved in many other functions including morphogenesis, and some activities that may be denominated as “social”, such as morphological responses, antigenic expression, adhesion, and cell-cell interaction (Peberdy 1990; Ruiz-Herrera 1992; Sentandreu et al. 1991). There are many data supporting the idea that temporal and spatial regulation of wall polymer synthesis and assembly are critical for the properties of the walls, which thus do not exclusiv…

Archaeal Cell Walls

2001

Archaea represent the third domain of life with the Bacteria and Eukarya. They have developed different types of cell envelopes. Keywords: glutaminylglycan; heteropolysaccharide; methanochondroitin; pseudomurein; S-layer (glyco-)protein; Archaea; cell envelope

Microtubules and cell shaping in the mesophyll ofNigella damascena L.

1993

Cell shaping in the mesophyll ofNigella damascena was investigated with the aim of determining the origin of the arm-like protrusions, which are characteristic of, e.g., arm-palisade cells. It was found that hoops of cell wall were deposited during the early stages of cell expansion. The hoops were interconnected, thus embracing the cells with a wide-meshed net of local wall reinforcement. The pattern of wall deposition in the extra-cellular matrix correlated with a pattern of bands of microtubules in the cortical cytoplasm of the cells. During lateral expansion bulges were forced through the comparatively thin walls of spaces between the meshes, giving rise to the arm-like protrusions. Aft…