Microbodies

Kawamoto S, C Nozaki, A Tanaka, S Fukui (1978) Fatty acid P-oxidation system in microbodies of -alkane-grown Candida tropicalis. Eur J Biochem 83 609-613. 

Hajra, A. K. Glycerolipid biosynthesis in peroxisomes (microbodies). Prog. Lipid Res. 34 343-364,1995. 

Microbodies (97-101) are spherical organelles (0.1-2.0 pm in diameter) bounded by a single membrane. They possess a granular interior and sometimes crystalline protein body. A specialized type of microbody is the glyoxysome (0.5-1.5 pm) containing enzymes ofthe glyoxy-late cycle. Glyoxysomes are found in the endosperm or cotyledons of oily or fatty seeds. 

Hogg JF. The Nature and Function of Peroxisomes (Microbodies, Glyoxysomes), New York Academy of Sciences, New York, 1969. 

Cavaher-Smith T. 1987. The simultaneous symbiotic origin of mitochondria, chloro-plasts, and microbodies. Ann NY Acad Sci 503 55-71. 

The cell organellae in woody plants are the nucleus, mitochondrion, rough-endoplasmic reticulum (r-ER), smooth endoplasmic reticulum (s-ER), Golgi-body, plastid, vacuole, microbody, etc. Their functions are very complicated, and some have definite roles in the biosynthesis of cell-wall components. Hence, changes in size of cell organellae are likely to occur, since cell-wall composition depends upon the stage of wall development. 

A). The envelope was often observed as a single entity (Fig. 7, 8S) and on occasions was not present at all (Fig. 7, arrow). In these moderately damaged cells, electron-dense accumulations also were often observed in association with the bounding envelope of the mitochondria (Fig. U, arrows). Other membranes in these cells such as the tonoplast, microbody membrane, and plasmalemma did not appear damaged, although mild-to-severe plasmolysis was not uncommon. 

Frederick SE, Newcomb EH, Vigil EL, Wergin WP (1968) Fine-structural characterization of plant microbodies. Planta 81 229-252 (Berlin)... 

Muller M (1975) Biochemistry of protozoan microbodies peroxisomes, alpha-glycerophosphate oxidase bodies, hydrogenosomes. Annu Rev Microbiol 29 467-483 Muller M (2003) Energy metabolism. Part I Anaerobic protozoa. In Marr JJ, Nilsen TW, Komnuniecki RW (eds) Molecular Medical Parasitology. Academic Press, New York, pp 125-139... 

Keith, A. Parson, M. Characterization of a divergent glycosomal microbody phosphoglycerate kinase from Trypanosoma brucei. Mol. Biochem. ParasitoL, 60, 265-272 (1993)... 

A response to exposure to certain foreign compounds, which occurs predominantly in the liver is the phenomenon of peroxisomal proliferation. Peroxisomes (microbodies) are organelles found in many cell types, but especially hepatocytes. Repeated exposure of rodents to certain... 

The geometry of cell construction provides another important aspect of metabolic control. In a bacterium, the periplasmic space (Fig. 8-28) provides a compartment that is separate from the cytosol. Some enzymes are localized in this space and do not mix with those within the cell. Other enzymes are fixed within or attached to the membrane. Eukaryotic cells have more compartments nuclei, mitochondria (containing both matrix and intermembrane spaces), lysosomes, microbodies, plastids, and vacuoles. Within the cytosol the tubules and vesicles of the endoplasmic reticulum (ER) separate off other membrane-bounded compartments. The rate of transport of metabolites through the membranes between compartments is limited and often is controlled tightly. 

Rather, the isolated subcellular fraction is a mitochondrial fraction, which indicates that its major components are mitochondria. Other cellular components that may be present are lysosomes, cell fragments, nuclear fragments, and microbodies (peroxisomes). The purity of the fraction depends on the source of the extract and the method chosen for isolation. 

For macroscopic objects the adhesion force is often small compared to the load. For microscopic bodies this can be different. The reason is simple the weight of an object sliding over a surface usually decreases with the third power of its diameter (or another length characterizing its size). The decrease of the actual contact area and hence the adhesion force follows a weaker dependence. For this reason, friction between microbodies is often dominated by adhesion while in the macroscopic world we can often neglect adhesion. 

K Alexander, T Hill, J Schilling, M Parsons. Microbody phosphoglycerate kinase of Trypanosoma brucer. expression and complementation in Escherichia coli. Gene 90 215-220, 1990. 

Peroxisomes or microbodies are spherical organelles that are 0.3-1.5 pm in diameter. Each peroxisome is enveloped by a single external membrane, and its interior is full of proteins, frequently in crystalline form. Peroxisomes are characterized by the presence of various oxidative enzymes, which have variable functions dependent upon the origin of the peroxisome. These enzymes generate and utilize hydrogen peroxide (H2O2), hence the name peroxisome. This compound is very toxic for cells and is decomposed by the enzyme catalase to water and oxygen. 

Electron microscopy of radish radicle, a) and b) Details of cortical cells from radicles of 2 h-imbibed control seeds, (a) Note the abundance of protein reserves in protein bodies (PB) and lipid reserves in the peripheral cytoplasm (arrows), (b) Numerous mitochondria (M) are visible among lipid bodies (L). (c-e) Details of cells from radicles of 16 h-imbibed control seeds, (c) Cortical parenchyma cells. The protein bodies have converted into normal vacuoles (V) and lipid reserves have been partially depleted, (d) Detail of epidermal cell showing a plastid (P) containing starch deposits (S). (e) Detail of cortical cell, showing several mitochondria (M) and a microbody (Mb). 

Examination of the root apex showed much the same effects as reported above (Fig. 15.6a-d). The calyptra was a particularly sensitive tissue, showing dramatic mitochondrial swelling at all dilutions tested (Fig. 15.6b-d). A conspicuous effect of the treatment with the RO fraction on the root apex was the inhibition of amyloplast development as statoliths in the columella cells of the calyptra (Fig. 15.6b-c). The almost complete lack of starch and of lipid-associated microbodies in... 

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