Eukaryotic microorganisms

Brown, A.D. (1978). Compatible solutes and extreme water stress in eukaryotic microorganisms. Advances in Microbial Physiology, 17, 181-242. 

In this chapter, we shall focus on the molecular aspects of amino acid transport and its regulation in Saccharomyces cerevisiae. Kinetic, biochemical and genetic aspects of the amino acid transport systems of eukaryotic microorganisms have been reviewed earlier [7,8]. 

Eukaryotic Microorganisms Fungi and Yeasts Metabolism by Fungi... 

The occurrence in some plants of secondary metabolites characterized by an 0-heterocyclic structure and exhibiting antimicrobial properties is a well-known phenomenon [2,8-10]. Among them, catechins and proanthocyanidins are two classes of compounds exhibiting antimicrobial properties towards both prokaryotic and eukaryotic microorganisms. Yet, despite the large number of studies published so far, the real potentialities and limitations given by the use of this class of molecules as antiviral or antimicrobial (antibacterial, antimycotic, antiprotozoal) agents have not been critically evaluated. The present chapter represents an overview of the re-... 

The mode of action of catechins on eukaryotic microorganisms has been studied little. In early investigations, Toyoshima et al. [93] suggested that catechins are able to attack the cell membrane of Trichosporon mentagrophytes causing lysis of the conidia and hyphae (Table 1). 

In spite of this redundancy of results, discrepancies among different data sets obtained from different laboratories on antimicrobial activity of these 0-heterocycles against both prokaryotic and eukaryotic microorganisms have been sometimes observed. This fact is probably due to various causes. 

It would be interesting to know if the mutational consequences of DNA lesions in mammalian cells were the same as those which obtain in bacteria. Methods for retrieving and sequencing mutations in mammalian cells and their viruses are now being developed (81-83) If yeast, a eukaryotic microorganism, can be considered representative of higher eukaryotes, then judging from the observations that the mutational spectra for UV-irradiation and 4-nitroquinoline-l-oxide treatment are identical for yeast (84) and bacteria (85), the spectrum of mutations induced by BPDE in mammalian cells could well resemble those induced in E. coli. 

Protists Eukaryotic microorganisms that are neither animal, fungi, plant, or archaean. Unicellular forms include the amoeboid protozoans and algae, such as the foraminferans and radiolarians, and dinoflagellates and diatoms, respectively. Some algae are either multicellular or colonial, such as the red algae and freshwater Volvox, respectively. 

The test is used to detect gene mutation in yeast, a eukaryotic microorganism. 

Much of what we have said here about signaling relates to mammalian tissues or cultured cells from such tissues. Bacteria, eukaryotic microorganisms, and vascular plants must also respond to a variety of external signals, such as 02, nutrients, light, noxious chemicals, and so on. We turn here to a brief consideration of the kinds of signaling machinery used by microorganisms and plants. 

Both procaryotic and eukaryotic microorganisms have the enzymatic potential to oxidize aromatic hydrocarbons that range in size from a single ring (e.g., benzene, toluene and xylene) to polycyclic aromatics (PC As), such as naphthalane, anthracene, phenanthrene, benzo [a] pyrene and benz [a] anthracene (Table 4.4). However, the molecular mechanisms by which bacteria and higher microorganisms degrade aromatic compounds are fundamentally different. 

A wide range of prokaryotic and eukaryotic microorganisms have the potential to produce cellulolytic enzymes when cellulose is present in the growth media (20,23,28,30). However, unlike some of the microorganisms that produce an incomplete cellulase system, T. reesei, a true cellulolytic fungus, produces an array of cellulase enzymes, i.e., the cellulase complex, which is able to hydrolyze cellulose to glucose (23). 

Eukaryotic microorganisms, with and without metabolic activation... 

Sogin ML (1989b) Evolution of eukaryotic microorganisms and their small subunit ribosomal RNAs. Am Zool 29 487-499... 

Whereas mainly cytosolic PolyP performs the function of phosphorus reservation in bacteria, in eukaryotic microorganisms phosphorus is also reserved as PolyP in other cell compartments. Under yeast growth on a medium without phosphate, the PolyP content drops by more than an order in the cytosol, vacuoles and cell walls (Kulaev and Vagabov, 1983 Kulaev et al, 1999). PolyP granules of the cytosol quickly disappear after the yeast has been placed in a phosphate-deficient medium. In a P -deficient medium, a sharp decrease of the PolyP level, both in whole cells and in vacuoles, was noted, and after 7 h of starvation the PolyP level in vacuoles decreased by 85 %, which indicates an active utilization of the entire PolyP pool for the needs of the cell under these growth conditions (Kulaev et al, 1999 Trilisenko et al, 2002). 

For eukaryotic microorganisms, the involvement of PolyPs in biochemical regulation under stress has also been observed. For example, the involvement of vacuolar PolyP in survival under osmotic or alkaline stress has been shown in algae and fungi. In the alga Dunaliella salina, alkalinization of the cytoplasm results in a massive hydrolysis of PolyP, resulting in pH stat. Various authors have suggested that the hydrolysis of PolyP provides the pH-stat mechanism to counterbalance the alkaline stress (Bental et al, 1990 Pick et al, 1990 Pick and Weis, 1991). 

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