Heterotrophic Organisms

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Heterotrophic Organisms

 

or heterotrophs, organisms that utilize organic compounds for nourishment (in contrast to autotrophic organisms, which are able to synthesize necessary organic substances from inorganic carbon, nitrogen, and sulfur compounds).

The heterotrophic organisms include all animals and man, as well as some plants (fungi and many parasitic and saprophytic angiosperms) and microorganisms. The division of plants and microorganisms into heterotrophic and autotrophic is rather arbitrary, however, despite the central difference in their type of metabolism. Even typical autotrophs, such as photosynthesizing green plants, can assimilate a certain amount of organic material from the soil through the roots, but their growth and development are better served by inorganic sources of nitrogen. Some green plants, which are capable of photosynthesis, are also insectivorous (for example, the sundew and the bladderwort); basically they use organic nitrogen, while their carbon nourishment is a product of photosynthesis. Some autotrophs require the presence of vitamin-like substances, which are necessary for autotrophic synthesis. In 1921 the Russian scientist A. F. Lebedev showed that even pronouncedly heterotrophic organisms (for example, certain bacteria and fungi) can assimilate CO2 carbon. This was confirmed isotopically in 1933 by the American scientists H. Wood and C. Werkman. Heterotrophic synthesis provides for minor accumulation of organic substances (up to 10 percent of the organism’s total carbon).

The possibility of CO2 assimilation by a cell without green (or other) pigment is of major significance in understanding the evolution of chemosynthesis and photosynthesis. The ability of animal tissues also to use CO2 has been shown. In this connection a tendency has arisen to differentiate organisms as autotrophs or heterotrophs not by the type of carbon nutrition but rather according to the character of the source of vital energy. In accordance with this tendency, those organisms for which the oxidation of complex organic compounds (hydrocarbons, fats, and proteins) serves as the carbon source are considered heterotrophic; those organisms which effect photochemical reactions are considered photo-autotrophs; and those organisms for which the source of energy is the oxidation of inorganic substances are considered chemoautotrophs. Animals and man are strictly heterotrophic organisms, using organic compounds to replace expended energy, to build and renew body tissues, and to regulate vital functions. These kinds of heterotrophic organisms differ in their need for one or another organic compound (depending upon the degree of its participation in the organism’s metabolism) and in the possibility of synthesis of these compounds by the organisms themselves. The so-called essential amino acids, the vitamins, and closely allied compounds are among those necessary substances which can not be synthesized by heterotrophic organisms. By decomposing complex organic substances and converting them to inorganic substances, heterotrophic organisms play an important role in the natural recycling of substances.

V. N. GUTINA

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
The dissolved organic matter (DOM) released by phytoplankton is a recognized source of high quality organic carbon for heterotrophic organisms, mainly bacterial populations (Giroldo et al., 2007; Sarmento and Gasol, 2012).
Likewise, in aquatic and terrestrial systems, not only autotrophic bacteria carry out the nitrification process; there are also other heterotrophic organisms that can do so, such as the Arthrobacter, Azotobacter gender, and bacterial species such as Pseudomonas fluorescens, and Aerobacter aerogenus, and fungi of Aspergillus, Penicillium, and Neurospora genders.
Conventional processes of ammonium removal involved nitrification by aerobic autotrophic organisms and denitrification by anaerobic heterotrophic organisms. However, such systems are time-consuming and inconvenience for management and operation due to the low rate of nitrification and the complexity of separating aerobic and anoxic tanks [2].
[26] refer that heterotrophic organisms can degrading the oil and increasing in number.
These observations precede the immobilization of ammonia, and may be related to the action of heterotrophic organisms. Therefore, the immobilization of nitrogen may have occurred heterotrophically, through the formation of bacterial biomass, and chemo-autotrophically through the development of nitrifying bacteria.
Giant clams are autotrophic and heterotrophic organisms, in contrast to several marine bivalves that have filter feeding as their sole energy source.
Specifically, they were differentiated by a filter set that provided blue excitation (495 nm), which resulted in red autofluorescence by chlorophyllous organisms and green fluorescence by heterotrophic organisms. HNF abundance was defined as the difference between total nanoflagellate abundance and PNF.
The pool water prior to mat compression was relatively free of target bacteria, where only heterotrophic organisms were found (at levels of 257 CFUs/100mL).
RESULTS: The average recovered concentration of respirable heterotrophic organisms found outside each home was 345.38 CFU/[m.sup.3], with an average of 12.63 CFU/[m.sup.3] for S.
For heterotrophic organisms the source of organic carbon for food can also be used as a defining characteristic.
Heterotrophic organisms in systems dominated by autochthonous production can also be limited by nutrients; bacterioplankton production was shown to be phosphorus limited in lakes (Morris and Lewis 1992).
They are rapidly replaced by aerobic (oxygen-utilizing) heterotrophic organisms. If this is occurring in Willmar, it is not evident from direct observation, because filamentous, iron-precipitating bacteria are notably absent from the well waters.