Single-celled organisms

Unicellular Single celled organism, such as bacteria. 

Rather early in the evolution of bacteriology it was noted that these single-celled organisms readily stain with organic dye molecules. An elaborate classification scheme can in fact be de-... 

The diverse group Protozoa consists of microscopic single-celled organisms. Of the various protozoan types, only Radiolaria and Dinoflagellata are known to contain luminous organisms (Harvey, 1952 Herring, 1978). 

In contemporary societies replete with various industries and automobiles, NO (NO, N02, and N03) has been recognized to be one of the important factors responsible for air pollution. Only two decades ago, NO was found to be an essential molecule that regulates cellular/molecular functions in mammals. NO is also enzymatically synthesized in nonmammals, invertebrates, and yeasts. Therefore, the origin of NO may date back to the birth of life arising from single cell organisms living around 3-billion years ago. 

The principal molecular constituent of thin filaments is actin. Actin has been highly conserved during the course of evolution and is present in all eukaryotes, including single-celled organisms such as yeasts. Actin was first extracted and purified from skeletal muscle, where it forms the thin filaments of sarcomeres. It also is the main contractile protein of smooth muscle. Refined techniques for the detection of small amounts of actin (e.g., immunofluorescence microscopy, gel electrophoresis, and EM cytochemistry) subsequently confirmed the presence of actin in a great variety of nonmuscle cells. Muscle and nonmuscle actins are encoded by different genes and are isoforms. 

The results for bacterial whole-cell analysis described here establish the utility of MALDI-FTMS for mass spectral analysis of whole-cell bacteria and (potentially) more complex single-celled organisms. The use of MALDI-measured accurate mass values combined with mass defect plots is rapid, accurate, and simpler in sample preparation then conventional liquid chromatographic methods for bacterial lipid analysis. Intact cell MALDI-FTMS bacterial lipid characterization complements the use of proteomics profiling by mass spectrometry because it relies on accurate mass measurements of chemical species that are not subject to posttranslational modification or proteolytic degradation. 

There is great interest in the electrical and optical properties of materials confined within small particles known as nanoparticles. These are materials made up of clusters (of atoms or molecules) that are small enough to have material properties very different from the bulk. Most of the atoms or molecules are near the surface and have different environments from those in the interior—indeed, the properties vary with the nanoparticle s actual size. These are key players in what is hoped to be the nanoscience revolution. There is still very active work to learn how to make nanoscale particles of defined size and composition, to measure their properties, and to understand how their special properties depend on particle size. One vision of this revolution includes the possibility of making tiny machines that can imitate many of the processes we see in single-cell organisms, that possess much of the information content of biological systems, and that have the ability to form tiny computer components and enable the design of much faster computers. However, like truisms of the past, nanoparticles are such an unknown area of chemical materials that predictions of their possible uses will evolve and expand rapidly in the future. 

Plants and single celled organisms have no means of autoregulating their operating temperature and thus their growth and replication are influenced by external conditions. Hence, we keep food at 4 °C in a refrigerator to prevent spoilage yet we incubate bacterial cultures at 37 °C and usually in a buffered medium when we wish to cultivate the cells for further study. 

Functional specialization of tissues and organs allows for greater efficiency than in single-celled organisms where all reactions and processes occur in close proximity. An analogy is to think of a typical university. It would not be conducive to learning... 

Protists Single-celled organisms more complex than bacteria that include protozoans and some types of algae. 

Simple single-cell organisms, such as bacteria and blue-green algae, are called prokaryotes (see Fig. A2.2). Prokaryotes do not have a well-defined nucleus. 

Information processing by biological systems is not an invention of the modern era. It started in the far past with the semblance of life on our planet, was operative in single-celled organisms, and was active throughout the ages with the evolution of higher species. 

At the same time, all cells are unified at the molecular level, as emphasized in the first chapter. There are other commonalities as well. All cells have a plasma membrane that surrounds and encloses them. The fundamental function of the plasma membrane is to act as a selective barrier between the cell interior and the external environment. In the Eubacteria and Archaea, single cell organisms all, the plasma membrane is the sole membrane of the cell. In contrast, in the Eukarya, there are a variety... 

The most widespread protozoan infections caused by pathogenic protozoa are malaria, leishmaniasis, and trypanosoma, as well as trichomonas, amebiasis, giardia, and toxoplasmosis. All types of protozoa are single-cell organisms that can adapt to various conditions. They are much more versatile than bacteria. They have a fairly complex life cycle, and therefore they exist in many forms. These forms require different approaches when treating patients that have protozoan infections. Protozoa are typical parasites that occupy host cells, multiply in them, and then destroy them. 

We can also use chemical kinetics to attempt to model populations of living systems such as single-celled organisms or plant, animal, and human populations. We describe the density of individuals (species A) as Ca, which might be in individualsA olume in a three-dimensional... 

Figure 8-19 Comparison of reactions of molecules, single-celled organisms, and more complex organisms. We can regard reproduction as a reaction such as those listed in the figure for chemicals and for living organisms.

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