Secondary Metabolism In Microorganisms Plants And Animals

Many of the reactions and compounds involved in metabolism are almost identical in the different groups of living organisms. They are known as primary metabolic reactions and primary metabolic products. In addition, however, a wide variety of biochemical pathways are characteristic of only a few species of organisms, of single "chemical races" or even of a certain stage of differentiation of special ized cells. Such pathways are collectively referred to as "secondary metabolism", and the compounds formed are called "secondary products". Secondary products are frequently revealed by their color, smell, or taste. They are responsible for the flavor of most foodstuffs and beverages and for the color and fragrance of flowers and fruits. Many of them are part of the materia medica, e. g. , alkaloids, cardiac glycosides, antibiotics, or compounds acting as hormones. Others are used by industry, e. g. , rubber, tannins, and cellulose. This book treats the organization and significance of biosynthesis, storage, transformation, and degradation of the most important groups of secondary products in microorganisms, plants, and animals. It shows that the formation of secondary products is a common characteristic of specialized cells brought about by the action of special enzymes encoded by specific genetic material. It demon strates that the. biosynthesis of secondary products is typically without signifi cance for the individual producer cell, but may play a decisive role in the develop· ment and function of the producer organism as a whole.

Many of the reactions and compounds involved in metabolism are almost iden tical in the different groups of living organisms. They are known as primary me tabolic reactions and primary metabolic products. In addition, however, a wide variety of biochemical pathways are characteristic of only a few species of organ isms, of single "chemical races", or even of a certain stage of differentiation of specialized cells. Such pathways are collectively referred to as "secondary metab olism", and the compounds formed are called "secondary products". Secondary products are frequently revealed by their color, smell, or taste. They are responsi ble for the flavor of most foodstuffs and beverages and for the color and fragrance of flowers and fruits. Many of them are part of the materia medica, e. g. , alka loids, cardiac glycosides, antibiotics, or compounds acting as hormones. Others are used in the industry, e. g. , rubber, tannins, and cellulose. This book treats the organization and significance of biosynthesis, storage, transformation, and degradation of the most important groups of secondary pro ducts in microorgimisms, plants, arid animals. It shows that the formation of sec ondary products is a common characteristic of specialized cells brought about by the action of special enzymes encoded by specific genetic material.

1. Secondary Metabolism and Differentiation In addition to the primary metabolic reactions, which are similar in all living beings (formation and breakdown of nucleic acids and proteins as well as of their precursors, of most carbohy drates, of some carboxylic acids, etc. ), a vast number of metab olic pathways lead to the formation of compounds peculiar to a few species or even to a single chemical race only. These reac tions, in accord with CZAPEK (1921) and PAECH (1950), are summed up under the term "secondary metabolism", and their products are called "secondary metabolites. " The wide variety of secondary products formed in nature includes such well-known groups as alkaloids, antibiotics, cardiac glyco sides, tannins, saponins, volatile oils, and others. A consider able number of them are of economic importance in therapeutics or technology. Although secondary products are produced by micro organisms, higher plants, and animals (cf. LUCKNER, 1972), most of the substances are found in the plant kingdom. The lack of mechanisms for true excretion in higher plants may result in this unequal distribution, the "waste products" of metabolism in plants instead being accumulated in the vacuoles, the cell walls, or in special excretory cells or spaces of the organism ("metabolic excretion," cf. FREY-WYSSLING, 1935, 1970; MOTHES, 1966a, b, 1972; LUCKNER et al. , 1976. Many secondary substances have, however, a direct biologic func tion. They can be regulatory effectors, e. g.

This book consists of an introductory overview of secondary metabolites, which are classified into four main sections: microbial secondary metabolites, plant secondary metabolites, secondary metabolites through tissue culture technique, and regulation of secondary metabolite production. This book provides a comprehensive account on the secondary metabolites of microorganisms, plants, and the production of secondary metabolites through biotechnological approach like the plant tissue culture method. The regulatory mechanisms of secondary metabolite production in plants and the pharmaceutical and other applications of various secondary metabolites are also highlighted. This book is considered as necessary reading for microbiologists, biotechnologists, biochemists, pharmacologists, and botanists who are doing research in secondary metabolites. It should also be useful to MSc students, MPhil and PhD scholars, scientists, and faculty members of various science disciplines.

Livestock species are either herbivores or omnivores that are maintained largely on plant-based diets. We have long appreciated the importance of understanding dietary plants from both nutritional and agronomic perspectives. However, it is increasingly clear that the fungi, bacteria and other microorganisms that live in the plants and animals are also significant factors in the ecology of agricultural animals. Many of the effects exerted on animals by dietary plants are attributable to secondary metabolites produced by the plants themselves or commensal microorganisms. Some fungal and plant secondary metabolites have multiple biological effects. We must be careful not to categorize a plant as strictly beneficial or harmful. Furthermore, we must be careful not to categorize even a particular plant or fungal compound as strictly beneficial or harmful. Rather, the harm or benefit of secondary metabolites are often dependent on the metabolic status of the animal, the interaction with other dietary factors including other secondary metabolites, and the dose received through the diet. This collection examines a range of agriculturally important plant and fungal products including essential oils, alkaloids, isoflavones and nitrates.