Peritrophic Membranes

ISBN-13: 9783642844164 / Angielski / Miękka / 2012 / 238 str.

Werner Peters

Opis

Peritrophic membranes are secretion products of the midgut. For long they have been related only to insects, but they occur widely in the animal kingdom. They effect a part of the gut lumen and function not only as a mechanical protection barrier, but also as an ultrafilter, a barrier to parasites, and as envelopes for fecal pellets. Such peritrophic envelopes are of great ecological importance in marine environments. The book is divided into the following themes: - Occurrence - Formation and Structure - Degradation - Chemical Composition - Functions. It is the first comprehensive compilation of all data concerning peritrophic membranes and will provide a basis for future researches in this up to now often neglected field.

Spis treści

1. Introduction.- 2. Occurrence of Peritrophic Membranes.- 3. Formation and Structure.- 3.1 Beginning of Secretion of Peritrophic Membranes.- 3.2 Textures of Microfibrils.- 3.3 Formation of Peritrophic Membranes.- 3.3.1 Formation Zones.- 3.3.2 Formation by the Whole Midgut Epithelium.- 3.3.3 Secretion of Peritrophic Membranes in Restricted Parts of the Midgut.- 3.3.3.1 Secretion of Peritrophic Membranes by Annular Groups of Cells in the Posterior Midgut.- 3.3.3.2 Secretion of Peritrophic Membranes in the Cardia.- 3.3.4 Crossbands in Peritrophic Membranes.- 3.3.5 Induction of Formation of Peritrophic Membranes.- 3.3.6 Rate of Formation of Peritrophic Membranes.- 3.3.7 Formation of Peritrophic Membranes in Vitro.- 3.3.8 Factors Influencing the Formation of Peritrophic Membranes.- 4. Degradation of Peritrophic Membranes.- 5. Chemical Composition.- 5.1 General Remarks.- 5.2 Chitin.- 5.2.1 Properties.- 5.2.2 The Chitosan Reaction.- 5.2.3 Enzymatic Degradation.- 5.2.4 Histochemical Methods for the Localization of Chitin.- 5.2.4.1 Electron Microscopy (TEM).- 5.2.4.2 Light Microscopy.- 5.3 Proteins and Glycoproteins.- 5.3.1 Amino Acids.- 5.3.2 Proteins.- 5.3.3 Glycoproteins.- 5.3.4 Lectins.- 5.4 Proteoglycans.- 6. Functions of Peritrophic Membranes.- 6.1 General Remarks.- 6.2 Lectins and the Association of Bacteria.- 6.3 Immobilized Enzymes.- 6.4 Permeability.- 6.4.1 Technical Problems.- 6.4.2 Water Transport Across Peritrophic Membranes.- 6.4.3 Permeability Properties of Peritrophic Membranes.- 6.4.4 Use of Peritrophic Membranes for Cellular Sieving.- 6.5 Compartmentalization of the Midgut by Peritrophic Membranes.- 6.5.1 Countercurrent Flow in the Midgut and the Role of the Midgut Caeca in Locusts.- 6.5.2 Countercurrent Flow in the Midgut and the Role of the Midgut Caeca of Mosquito Larvae.- 6.5.3 Compartmentalization of the Midgut and Diversity of Enzymes.- 6.6 Peritrophic Membranes as a Barrier to Parasites.- 6.6.1 Viruses.- 6.6.2 Bacteria.- 6.6.3 Actinomycetes.- 6.6.4 Flagellata.- 6.6.5 Sporozoa.- 6.6.6 Microsporida.- 6.6.7 Larvae of Cestoda.- 6.6.8 Microfilariae.- 6.6.9 Summary.- 6.7 Fecal Pellets or Ecological Aspects of Peritrophic Membranes.- 6.7.1 Aquatic Ecosystems.- 6.7.2 Fecal Pellet Membranes = Peritrophic Envelopes.- 6.7.3 Production.- 6.7.4 Contents of Fecal Pellets.- 6.7.5 Pollutants in Fecal Pellets.- 6.7.6 Sinking Rates.- 6.7.7 Digestion-Resistant Components.- 6.7.8 Nutritional Content.- 6.7.9 Colonization of Fecal Pellets by Microorganisms.- 6.7.10 Coprophagy.- 6.7.11 Coprorhexy.- 6.7.12 Sediment Formation.- 6.7.13 Element Depletion in Surface Layers and Recycling Problems.- 6.7.14 Terrestrial Ecosystems.- 6.8 Peritrophic Membranes Used as Cocoon Material for Pupation.- References.

O autorze

Dr. Werner Peters, geboren 1941 in Düsseldorf, studierte Altphilologie und Philosophie in Tübingen und Bonn, Abschluss mit der Promotion zum Dr. phil. 1967. Langjähriger Studienaufenthalt in den USA, u.a. an der Harvard Universität und als Assistent im US-Kongress. 1970 bis 1972 politischer Referent in der Bundesgeschäftsstelle der CDU in Bonn. Danach als selbstständiger Politikberater tätig. Seit 1983 Inhaber des Künstlerhotels "Chelsea" und des "Café Central" in Köln.