Cloning of rabbit uricase cDNA reveals a conserved carboxy-terminal tripeptide in three species

cDNA clones encoding uricase have been isolated from a rabbit liver cDNA library. The nucleotide sequences of the cDNAs have been determined and those of the rat uricase cDNA have been revised. In all three uricases, the carboxy-terminal tripeptides are Ser-Arg/Lys-Leu sequences, which have recently been suggested as an essential element of peroxisomal targetting signals for many but not all peroxisomal proteins.     

Two-dimensional flow cytometric analysis of T cell subsets maintained in IL-2 medium after autologous mixed leukocyte reaction activation

Human T cells are stimulated with an autologous mixed leukocyte reaction (AMLR) and can be propagated in interleukin-2. Staining of the cultured cells with the combination of two monoclonal antibodies was evaluated by two-dimensional flow cytometry at weekly intervals. AMLR activation resulted in an initial preservation of the CD4+ (helper/inducer T) subset predominance over the CD8+ (suppressor/cytotoxic T) cells, noted on normal circulating blood lymphocytes. However, during culture in interleukin-2, there was a progressive increase in the percentages of CD8+ Leu 15- cytotoxic T, CD4+ Leu 8- helper T, and CD3+ HLA-DR+ activated T cells, and a concomitant decrease in those of CD4+ Leu 8+ suppressor inducer T and CD8+ Leu 15+ suppressor T cells if the responder sheep red blood cell (SRBC)-rosetting T cells were made up by tris ammonium chloride, but not by hypotonic shock treatment to lyse SRBC. The significant difference between hypotonic shock-T cells and ammonium chloride-T cells in the phenotypic changes of T cell subsets after long-term culture in an interleukin-2 medium may suggest a regulatory role of the ammonium chloride-sensitive T cells in the AMLR.     

Individual growth and smoltification of juvenile masu salmon, Oncorhynchus masou Brevoort, under rearing conditions

In a reared population of individually marked juvenile masu salmon, individual growth was monitored from the first autumn in 1983 to the following spring. The potential smolts were not significantly greater in mean fork length and body weight than the potential parr in late August of the first year, but they then grew faster until March of the second year. As a result, the potential smolts formed the upper mode of the bimodal length distribution after February. Especially in autumn (October and November) the specific growth rates of potential smolts were significantly greater than those of parr, and the bimodality in growth rate distribution was more distinct for males than females. These suggest that there are two groups having different growth rates in autumn of the first year and that sufficient growth in this period may play an important role in smoltification in the following spring.     

Chimeric heterosis in mandibular size in mice

Morphometrical observations were carried out on the mandibles of chimeras made from the embryos of C57BL/6 and BALB/c mice to compare with the two strains and their reciprocal F1 crosses. The results of the principal component analysis indicate that the first principal component (PC1) and the second principal component (PC2) extracted might be acceptable as size and shape factors, respectively. Variations of both PC1 and PC2 were generally larger in the chimeras than in the two component strains and their F1 crosses. The mean PC1 value of the chimeras was larger than that of the two component inbred strains, and it was similar to that of F1 crosses, or slightly larger. The overall size of the mandible represented by PC1 tended to be larger in the chimeras consisting of two component cells that were approximately equivalent than in those that shifted to either cell population. The above trend was observed in both sexes. These results indicate that chimeric heterosis due to the interaction between genetically different cells (C57BL/6 and BALB/c) has some relation to mandible size. The mean PC2 value, which was accepted as shape factor, was intermediate between the two inbred strains. The mandible size (PC1) and shape (PC2) were bilaterally symmetrical, except for the shape in the female chimeras and in (C57BL/6 x BALB/c)F1.     

Preparation and characterization of two major isotypes of parvalbumins from skeletal muscle of bullfrog (Rana catesbeiana)

Two major isotypes of parvalbumins (PA1 and PA2) have been isolated from the skeletal muscle of bullfrog, Rana catesbeiana. The Mr values were estimated to be 10,100 (PA1) and 11,800 (PA2) by SDS/polyacrylamide gel electrophoresis, and the isoelectric points were determined to be 4.78 (PA1) and 4.97 (PA2) by polyacrylamide gel isoelectric focusing. The amino acid compositions and isoelectric points indicate that PA1 corresponds to Rana esculenta pI 4.50 and Rana temporaria pI 4.75 parvalbumins and PA2 to Rana esculenta pI 4.88 and Rana temporaria pI 4.97 parvalbumins, showing that PA1 is genetically a beta-parvalbumin and PA2 an alpha-parvalbumin. However, in terms of the amino acid compositions, PA1 and PA2 are distinctly different from the corresponding parvalbumins of Rana esculenta or Rana temporaria. The ultraviolet spectra of PA1 and PA2 are consistent with their amino acid compositions. An ultraviolet difference spectrum of the Ca2+-loaded form vs. metal-free form indicates that a Tyr and some Phe residues in PA1 are affected by a conformational change associated with the binding of Ca2+. On electrophoresis in polyacrylamide gel in 14 mM Tris and 90 mM glycine, the Ca2+-loaded form of PA1 migrated twice as fast as the Mg2+-loaded form. Both PA1 and PA2 show increased mobility in the Ca2+-loaded forms, like troponin C but different from calmodulin.     

Inheritance of hydronephrosis in the inbred mouse strain DDD

The mode of inheritance of hydronephrosis was investigated by crossing inbred DDD mice having a high incidence of hydronephrosis and C57BL/6 mice having normal kidneys. In the males, incidences of hydronephrosis in F1 animals were intermediate between the two parental strains at a rate of 32.6% in (DDD x C57BL/6)F1 and 23.4% in reciprocal F1. The same tendency was observed in F2 male animals. In BCF1 males, the number of affected mice was higher in (C57BL/6 x DDD) F1 x DDD (72.4%) than in (DDD x C57BL/6)F1 x C57BL/6 (11.1%). A few affected mice were found among the females of hybrids F1, F2 and BCF1. These results suggested that hydronephrosis in the DDD strain of mice was controlled by polygenes, and that male hormones may have some effect on the occurrence of hydronephrosis.     

Inhibition of gastric acid secretion by intracerebral injection of calcitonin gene related peptide in rats

Calcitonin gene related peptide (CGRP), a 37 amino acid peptide recently characterized from the rat brain, injected into the cisterna magna or the lateral hypothalamus, inhibited gastric acid secretion and increased serum gastrin levels in conscious pylorus-ligated rats. CGRP suppressed pentagastrin- and histamine-induced stimulation of gastric secretion in urethane-anesthetized gastric fistula rats. Peptide action was dose-dependent, not modified by adrenalectomy and peripheral sympathectomy induced by guanethidine pretreatment and reversed by vagotomy. These results demonstrate that intracisternal or intralateral hypothalamic injection of CGRP inhibits stimulated gastric acid secretion. The mechanism of action is vagal dependent and unrelated to modification of gastrin secretion or activation of sympathetic outflow.