scholarly journals COMPARATIVE AUTOSOMAL LINKAGE IN MAMMALS: GENETICS OF ESTERASES IN MUS MUSCULUS AND RATTUS NORVEGICUS

Genetics ◽  
1976 ◽  
Vol 82 (4) ◽  
pp. 665-675
Author(s):  
James E Womack ◽  
Mark Sharp

ABSTRACT Recombination between Esterase-4 and Esterase-2 in the rat was not observed in 278 backcross offspring. Es-4 is thus included within the "esterase cluster" in Linkage group V. A new map of this region was constructed and the relationship of the four esterase loci was found to be: Es-4-(9.6 ± 1.6 cM)-Es-2, Es-4-(1.5 ± 0.7 cM)-Es-3. Homology of this region with a region of Linkage Group XVIII (Chromosome 8) of the mouse was proposed on the basis of tissue distribution, subcellular localization and response of enzymes to inhibitors. Specifically, rat Es-1 was suggested as the homolog of mouse Es-2, rat Es-2as the homolog of mouse Es-1, and rat Es-4 as the homolog of mouse Es-6. An autosomal segment comprising at least 15 cM of the rat and mouse genomes appears to have remained relatively intact with respect to genetic content during rodent speciation. In addition, a new polymorphism for mouse esterase was described. The locus was designated Esterase-10 (Es-10) and proposed as the mouse homolog of human Esterase D. Linkage of Es-10 with nucleoside phosphorylase-1 (Np-1) on Chromosome 14 was established.

1983 ◽  
Vol 17 (3) ◽  
pp. 221-224 ◽  
Author(s):  
P. B. Kendall

2 new esterase polymorphisms ( Es-12 and Es-13) were discovered in haemolysates of wild rats ( Rattus norvegicus) by gel electrophoresis. Both loci are probably monomeric. Linkage analysis indicates that neither locus is associated with the esterase cluster in linkage group V.


1956 ◽  
Vol 188 (1) ◽  
pp. 118-120 ◽  
Author(s):  
Jack D. Burke

The oxygen capacity of the blood of 64 albino Rattus norvegicus (Sherman strain) was determined by the microgasometric syringe method. Data were obtained showing the relationship of blood oxygen capacity to weight and sex of the animals. It was found that blood oxygen capacity in volumes per cent increased as the weight of the rats increased. Statistically, there was no difference in the blood values in either male or female rats as analyzed in different weight groups and ranges. Also, the oxygen capacity of the blood per unit of body weight decreased as the weight of the rats increased.


Genetics ◽  
1979 ◽  
Vol 93 (1) ◽  
pp. 183-188
Author(s):  
R R Fox ◽  
L F M Van Zutphen

ABSTRACT Homologous portions of linkage group (LG) VI in the rabbit Oryctolagus cuniculus, chromosome 8 in Mus musculus, and LG V of Rattus norvegicus have been observed. These linkage groups in Oryctolagus and Mus contain the extension locus (e), where recessive alleles are known in many species. Preliminary linkage data have added new loci to linkage group VI of the rabbit, revised the order and map distances on the linkage map, and by comparison with rodent species have strengthened the homology of LG VI in the rabbit with chromosome 8 of the mouse and with LG V of the rat. LG VI now contains five loci with the following order and intervening map distances: Es-1, Es-2 complex—6.3 ± 2.1 cM—Est-1, Est-2 complex—18.5 ± 3.7 cM—e.


Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.


Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.


Author(s):  
Leon Dmochowski

Electron microscopy has proved to be an invaluable discipline in studies on the relationship of viruses to the origin of leukemia, sarcoma, and other types of tumors in animals and man. The successful cell-free transmission of leukemia and sarcoma in mice, rats, hamsters, and cats, interpreted as due to a virus or viruses, was proved to be due to a virus on the basis of electron microscope studies. These studies demonstrated that all the types of neoplasia in animals of the species examined are produced by a virus of certain characteristic morphological properties similar, if not identical, in the mode of development in all types of neoplasia in animals, as shown in Fig. 1.


Author(s):  
J.R. Pfeiffer ◽  
J.C. Seagrave ◽  
C. Wofsy ◽  
J.M. Oliver

In RBL-2H3 rat leukemic mast cells, crosslinking IgE-receptor complexes with anti-IgE antibody leads to degranulation. Receptor crosslinking also stimulates the redistribution of receptors on the cell surface, a process that can be observed by labeling the anti-IgE with 15 nm protein A-gold particles as described in Stump et al. (1989), followed by back-scattered electron imaging (BEI) in the scanning electron microscope. We report that anti-IgE binding stimulates the redistribution of IgE-receptor complexes at 37“C from a dispersed topography (singlets and doublets; S/D) to distributions dominated sequentially by short chains, small clusters and large aggregates of crosslinked receptors. These patterns can be observed (Figure 1), quantified (Figure 2) and analyzed statistically. Cells incubated with 1 μg/ml anti-IgE, a concentration that stimulates maximum net secretion, redistribute receptors as far as chains and small clusters during a 15 min incubation period. At 3 and 10 μg/ml anti-IgE, net secretion is reduced and the majority of receptors redistribute rapidly into clusters and large aggregates.


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