Ecological world

T here are approximately million named species of living oganisms. The total number of living species is of course not known and we can only estimate what the figure might be. Estimates range from about 11 to 30 million or more. What is certain is that human impacts are causing species to become extinct faster than they can be named. Also of concern is our lack of knowledge about the named species. Scientists have intensively investigated only 10 per cent of plant species and a far smaller proportion of animal species (information from the World Commission in Environment and Develop-ment 198- publication Our common Future, Oxford University Press).  There are many terms used to refer to different groups of animals, plants and other kinds of living organism such as fungi, bacteria and viruses. The classification of biota (living organisms) has been reviewed and changed many times as a result of new information. In 1969, R. H. Whittaker of Cornell University suggested...

The term mold originates from daily life and is not a taxonomic. name of a single systematic group (Reiss 1997; Killerand Morelet 1000). The Deuteromycetes (fungi imperfecti) constitute an artificial group and comprise a great variety of 20,000 -30,000 species of 1,700 genera of I-1 phomycetes and 700 genera of Coelomycetes.  The different molds have a broad spectrum of physiological response with regard to temperature, water activity, pH value etc. and thus can colonize and damage very diverse materials (molding).  Molds are significant in view of damages to foodstuffs, deterioration of natural materials (leather, books, textiles, wallpapers), Nv t h regard to human and animal health, and for biochemists and the manufacturers of antibiotics [77) of about 3,200 admitted antibiotics Originate from fungi: Muller and Loeffler (1991)], organic acids e.g., citronic acid, malic acid: Rehm (1980)1, enzymes (e.g., amylase, protease, lipase, cellulase, pectinase), cheese (Peni...

The damage of wood by fungi is essentially caused by the degradation of the cell wall by fungi, which decreases the mechanical wood properties and substantially reduces wood use.  However, wood quality is also influenced by bacterial, algal and fungal discolorations (e.g., Grosser 1985; Zabel and Morrell 1992; Eaton and Hale 1993). Discolorations in the wood of living trees, in round wood, timber and wood in service are long-known problems and are based on different biotic and abiotic causes (Bauch 1984, 1986; Kreber and Byrne 1994; Koch et al. 2002; Koch 2004; ).  Discolorations in standing trees occur after wounding by wound reactions of the tree  and by the colonization of the stemwood with bacteria and fungi as a result of microorganism-own pigments (e.g., melanin of blue-stain fungi, Zink and Fengel 1989) or of their metabolism (brown, white, and soft rot in trees, chemical reactions of accessory compounds after pH-change by wetwood bacteria and in the spla...

Viruses  Viruses are small particles (1.0-2,000 tun in size) that infect rtikaryoles as obli gate intracellular parasites. They reproduce by invadiny and (Ain), over other cells as they lack own metabolism and the machinery for sell reproduct ion (Nienhaus 1985a).  Typically, they carry either DNA or RNA surrounded by a coat of protein or protein and lipid. Plant viruses penetrate the shoot, leaf tissue and root via wounds or they are transferred by vectors I aphids, ci-cadas, nematodes, among fungi: Sphaerotheca lanestris (Erysiphales) on oak I. Partial bleaching of chlorophyll results in angular, circular (mosaic) or dif-fuse chloroses. Leaf damage, dwarfing or growth inhibition, distorted growth, and necrotic areas or lesions can occur, that is, virus infection can reduce the tree growth. Over 1,000 virus diseases of plants are described for Europe. Virus diseases in forest trees have been summarized e.g., by Nienhaus and Castello (1989) and Cooper and Edwar...

 Enzymes and Low Molecular Agents               In view of the historical development of the research on wood degration by fungi, this chapter starts with the enzymes invoiveti in the de woody cell Null, although it is now commonly accepted that non-enzymatic low molecular weight metabolites are involved as precursors and / or co-agentswith enzymatic cell wall degradation.  Under the conditions within microbial cells, namely an aqueous environment with pH values around 6 and temperatures of I -50"C, most reactions would run off only very slowly. Enzymes reduce the amount of the necessary activation energy as biocatalysts and control the reaction by substrate and effect specificity.  More than 3,000 enzymes are described. Comparable with the lock/key principle, enzymes possess an active center, into which the substrate must fit, and which thus controls the conversion of the correct substrate (substrate specificity). The...

Learn about the biosphere, ecosystems, communities, populations, organisms, habitats, niches, generalists, specialists, biotic and abiotic factors in this video!