Fungi others

In addition to the 20 amino acids most frequently found in proteins a large group of amino acids occur in plants, bacteria, and animals that are not found in proteins. Some are found in peptide linkages in compounds that are important as cell wall or capsular structures in bacteria or as antibiotic substances produced by bacteria and fungi. Others are found as free amino acids in seeds and other plant structures. Some amino acids are never found in proteins. These nonprotein amino acids, numbering in the hundreds, include precursors of normal amino acids, such as homoserine and diaminopimelate intermediates in catabolic pathways, such as pipecolic acid d enantiomers of normal amino acids and amino acid analogs, such as azetidine-2-carboxylic acid and canavanine, that might be formed by unique pathways or by modification of normal amino acid biosynthetic pathways. 

Fungi (e.g. Cunninghamella sp., Aspergillus sp., Saccharomyces cerevisiae) are eukaryotic organisms, like mammals, and are the most commonly utilized microorganisms in biotransformation studies [31, 32]. The use of bacteria (prokaryotes) is limited mostly to actinomycetes that seem to contain an enzyme system very similar to that of fungi. Other bacteria (e.g. Pseudomonas, Escherichia coli) are used occasionally, but their usefulness is limited [26, 33]. 

The coloration in green algae is due to chlorophyll a and b. Most of the species are aquatic, and are found commonly in fresh water and marine habitats some are terrestrial, growing in soil, trees, or rocks. Some are symbiotic with fungi, others are symbiotic with animals, e.g., the fresh water coelenterate Hydra has a symbiotic species of chlorella. Chlorella is sold as a health supplement (Wong and Cheung, 2000). 

Initial reaction. In all known cases of effective biotic sensitization of plants reported to date, a critical factor appears to be the necrosis of host cells in the zone of initial infection. However, while non-necrotic infections are ineffective inducers, necrosis per se is not effective in inducing resistance. Injury by abiotic agents such as heat, chemicals, dry ice, or various extracts from plants and microbes does not protect cucumbers against lagenarium (8-10). Infection of tobacco by a wide variety of Peronosporales fungi other than P. tabacina frequently causes severe necrosis, but does not induce systemic resistance against blue mold (Tiizun and Kuc, unpublished). 

Disturbances of the cytoskeleton, DNA replication, and DNA topoisomerase, or DNA alkylation and intercalation usually lead to cell death by apoptosis [18] (Table 1.2). The cytotoxic properties are usually not specific for animals but also affect bacteria, fungi, other plants, and even viruses. Alkaloids thus defend plants against a wide diversity of enemies. They have the disadvantage that a producing plant could theoretically kill itself by its own poison. Compartmentation, target-site insensitivity, and other mechanisms (which are largely unknown) must have evolved to overcome such problems. 

A major proportion of the organic matter on Earth is plant tissue ( biomass ) and is composed of carbohydrates, principally cellulose. This is the structural support polymer of land plants and the material used since ancient times in the form of cotton and linen textiles, and later as paper. Chitin is a polymer related to cellulose that has skeletal function in arthropods and fungi. Other polymeric carbohydrates constitute the structural support framework for marine plants and the cell walls of microorganisms. The sweet carbohydrate of sugar cane, now termed sucrose, has been a dietary item for at least 10 millennia. 

Matthiesson AM. Allergic bronchopulmonary disease caused by fungi other than Aspergillus [letter]. Thorax 1981 36 719. 

---