We investigated the immunoreactivity of the peroxisomal lipid 0-oxidation enzymes acyl-CoA oxidase, trifunctional protein, and thiolase in guinea pig liver and compared it with that of homologous proteins in rat, using immunoblotting of highly purified peroxisomal fractions and monospecific antibodies to rat proteins. In addition, the immunocytochemical localization of 0-oxidation enzymes in guinea pig liver was compared with that of catalase. All antibodies showed crossreactivity between the two species, indicating that these peroxisomal proteins have been well conserved, although all exhibited some differences with respect to molecular size and, in the case of acyl-CoA oxidase, in frequency of the immunoreactive bands. In the latter case,

Peroxisomes are cell organelles that perform multiple functions in the metabolism of lipids and of reactive oxygen species. They are present in most eukaryotic cells. However, they are believed to be absent in spermatozoa and they have never been described in male germ cells. We have used the immortalized germ cell line GC1spg to investigate the expression of peroxisomal proteins in germ cells of mice. The GC1spg cells represent the differentiation state of type B spermatogonia or preleptotene spermatocytes. We could show that peroxisomal membrane proteins like Pmp70 and Pex14p as well as peroxisomal matrix proteins like catalase or acyl CoA oxidase are expressed in GC1spg cells. All these proteins were colocalized in the same structures within the cells. Furthermore, by electron microscopy we have identified subcellular particles with an ultrastructural appearance that is characteristic of peroxisomes. This is the first report demonstrating the peroxisomal compartment in male germ cells of mice.

No abstract

Book ReviewslFEBS Letters 381 (1996) 262~66265 readership, and would probably be found excessively detailed and specialized by even final-year undergraduates. Most of the reviews cite 51%100 references, dated up to 1994.The first section, on signal transduction, covers the cellular roles of RAS proteins, casein kinase-2, and G-protein coupled P2 purinoreceptors. The next section contains six reviews on membrane traffic, including the import of proteins into mitochondria and of bacterial toxins into eukaryotic cells, the functions of non-clathrin coat proteins in vesicular traffic and of rab5 in endocytosis, the control of autophagy, and the intracellular traffic of glycosphingolipids. The book's stated emphasis on structure-function relationships is rather less obvious in these two sections than in later ones. Rather surprisingly, vesicle targetting and fusion, currently a very hot topic, is not covered perhaps it was decided that the area is already sufficiently reviewed. There follow four contributions on bioenergetics (H+-translocation by the mitochondrial electron-transport chain, the assembly, control and mechanism of ATP synthase, and structures of mitochondrial transporters). The mechanistic controversies that continue to attend the mechanism and stoichiometry of proton-pumping by the electrontransport chain are explored, but are only touched on for F~F 0.The next sections cover some relatively unfamiliar topics -cyclic ADP-ribose in erythrocytes, Mg 2* homeostasis in the heart and the role of mucins in cell adhesion -as well as signal transduction by growthfactor receptors and by fll-integrin.Three contributions on the structures of membrane proteins (intramembrane helix interactions; annexin V; and porin) are preceded by a brief overview of the topic. Finally, a single review in the section on membranes and disease covers the possible involvement in ageing and disease of damage to mitochondrial DNA.In general the clarity and organization of these reviews are excellent. The figures, mostly line-drawings and monochrome of course, are adequate without being beautiful. The editors have done a fine job in achieving balance, breadth and a consistently high quality of content, although there are minor criticisms: the three-page comparison of 65 amino-acid sequences of transporters, for which readers with average vision will need a magnifying glass, could surely have been omitted; the index adds little to the usefulness of the book; and the basis for assigning topics to particular sections is not obvious -as is the reason for division into sections at all, as with one exception there are no overviews, and there is no inter-referencing between reviews. Never mind: each topic covered fulfils the criteria of intrinsic interest and recent progress, and each review contributes handsomly to a very worthwhile collection.David The peroxisome has been the neglected child in text books of cell biology and there has been a void on informative up-to-date texts dealing with this organelle. The last review-book by B6ck et al...

The intracellular localization of beta-NADPase in rat hepatocytes and Kupffer cells has been studied and compared with the pattern of TPPase in these cells. The reaction product for beta-NADPase is present in some but not all hepatocytes in two cisternae on the trans aspect of the Golgi apparatus. It is absent from the trans-most lamella and the GERL of hepatocytes. TPPase, on the other hand, is limited to the first Golgi cisterna on the trans aspect with sprinkles of reaction product in the second lamella. Considering that TPPase is a marker of the trans Golgi lamella and hepatocyte Golgi stacks contain usually 2-4 lamellae, our observations suggest that beta-NADPase is localized in the trans as well as in the intermediate Golgi lamellae of liver parenchymal cells. In Kupffer cells, the reaction product for both beta-NADPase and TPPase was found in some but not in all cells. The enzyme beta-NADPase was localized in the rigid lamella and the tubulovacuolar system of GERL. This pattern differed significantly from that for TPPase, which was found in 2-3 cisternae at the trans aspect of the Golgi complex in Kupffer cells. These observations demonstrate the difference in the localization of beta-NADPase in hepatocytes and Kupffer cells. Such differences should be taken into consideration in studies of Golgi fractions, when phosphatase reactions are used as specific markers of Golgi components.