FINE STRUCTURE OF PACINIAN CORPUSCLES IN THE MESENTERY OF THE CAT

Pacinian corpuscles in the mesentery of adult cats were fixed with either glutaraldehyde, osmium tetroxide or permanganate solutions by close intra-arterial injection through the mesenteric artery, and were processed, after electron staining and Epon embedding, for electron microscopy. Better resolution of the corpuscle's ultrastructure was obtained than available heretofore. The myelinated segment of the corpuscle contains blood vessels separated from the axon by collagen fibers and 3 to 4 layers of lamellae. No blood vessels are found in the central core, though access from the vessels is afforded by diffusion through the "cleft" of the inner core. Two cell types are discernible in the inner core hemilamellae; the "clear cells" in which pinocytotic vesicles and organelles abound and reflect the greater metabolic activity of these cells, in contrast to the "dark cells." The ultraterminal is ellipsoidal in form with projections into the "cleft" which give this portion an irregular appearance in section. The terminal and ultraterminal are packed with mitochondria, and "synaptic" vesicles are seen in the ultraterminal. The innermost laminae of the inner core cells are in close apposition to the terminal and break their regular pattern of hemilamellation to surround the small ultraterminal projections at the apical part of the corpuscle.     

Stimulation of pituitary-adrenocortical system by ginseng saponin.

Effects of preparations of saponin mixture and isolated ginsenosides, extracted from the root of Panax ginseng, on plasma corticotropin (ACTH) and corticosterone concentrations in rats were determined by the radioimmunoassay and competitive protein binding method. When ginseng saponin mixture was administered to rats intraperitoneally, plasma ACTH and corticosterone increased significantly 30, 60 and 90 min after the treatment. The kinetic pattern of the increase in plasma ACTH was almost parallel to that in plasma corticosterone. Isolated ginsenoside, protopanaxadiol or protopanaxatriol glycoside, also increased plasma corticosterone. The ginseng-induced increase in plasma corticosterone was suppressed by pretreatment with dexamethasone. Thus the ginseng saponin was found to act on the hypothalamus and/or hypophysis primarily, and stimulated ACTH secretion which resulted in increased synthesis of corticosterone in the adrenal cortex.     

Effect of aeration on the activity of gluconeogenetic enzymes in Saccharomyces cerevisiae growing under glucose limitation

1. The effect of aeration on the key enzymes of gluconeogenesis was studied in baker's yeast (Saccharomyces cerevisiae) and in a nonrespiratory variant of S. cerevisiae grown under glucose limitation. 2. In baker's yeast phosphoenolpyruvate carboxykinase, hexosediphophatase and isocitrate lyase were completely repressed under anaerobic conditions. Their repression could be partially reversed by using intense aeration. 3. In the nonrespiratory variant these enzymes were absent independently of aeration. 4. Pyruvate carboxylase of baker's yeast showed maximal activity under anaerobic conditions. In the nonrespiratory variant pyruvate carboxylase had low activity under both anaerobic and aerobic conditions.     

Trim41 is required to regulate chromosome axis protein dynamics and meiosis in male mice

Meiosis is a hallmark event in germ cell development that accompanies sequential events executed by numerous molecules. Therefore, characterization of these factors is one of the best strategies to clarify the mechanism of meiosis. Here, we report tripartite motif-containing 41 (TRIM41), a ubiquitin ligase E3, as an essential factor for proper meiotic progression and fertility in male mice. Trim41 knockout (KO) spermatocytes exhibited synaptonemal complex protein 3 (SYCP3) overloading, especially on the X chromosome. Furthermore, mutant mice lacking the RING domain of TRIM41, required for the ubiquitin ligase E3 activity, phenocopied Trim41 KO mice. We then examined the behavior of mutant TRIM41 (ΔRING-TRIM41) and found that ΔRING-TRIM41 accumulated on the chromosome axes with overloaded SYCP3. This result suggested that TRIM41 exerts its function on the chromosome axes. Our study revealed that Trim41 is essential for preventing SYCP3 overloading, suggesting a TRIM41-mediated mechanism for regulating chromosome axis protein dynamics during male meiotic progression.     

Relationship between the Circadian Variation of Uric Acid Level and Dietary Conditions

We studied the inhibitory effects of isorhamnetin on mushroom tyrosinase by inhibition kinetics and computational simulation. Isorhamnetin reversibly inhibited tyrosinase in a mixed-type manner at K _i=0.235 ± 0.013 mM. Measurements of intrinsic and 1-anilinonaphthalene-8-sulfonate(ANS)-binding fluorescence showed that isorhamnetin did not induce significant changes in the tertiary structure of tyrosinase. To gain insight into the inactivation process, the kinetics were computed via time-interval measurements and continuous substrate reactions. The results indicated that inactivation induced by isorhamnetin was a first-order reaction with biphasic processes. To gain further insight, we simulated docking between tyrosinase and isorhamnetin. Simulation was successful (binding energies for Dock6.3: ?32.58 kcal/mol, for AutoDock4.2: ?5.66 kcal/mol, and for Fred2.2: ?48.86 kcal/mol), suggesting that isorhamnetin interacts with several residues, such as HIS244 and MET280. This strategy of predicting tyrosinase interaction in combination with kinetics based on a flavanone compound might prove useful in screening for potential natural tyrosinase inhibitors.     

Linkage disequilibrium between alleles at highly polymorphic mini- and micro-satellite loci of Theileria parva isolated from cattle in three regions of Kenya

Theileria parva schizont-infected lymphocyte culture isolates from western, central and coastal Kenya were analysed for size polymorphism at 30 T. parva-specific variable number tandem repeat (VNTR) loci using a panel of mini- and micro-satellite markers. The mean number of alleles ranged from 3 to 11 at individual loci and 183 distinct alleles were observed in total, indicating high genetic diversity within the T. parva gene pool in Kenyan cattle. The frequency distribution of the length variation of specific alleles among isolates ranged from normal to markedly discontinuous. Genetic relationships between isolates were analysed using standard indices of genetic distance. Genetic distances and dendrograms derived from these using neighbour-joining algorithms did not indicate significant clustering on a geographical basis. Analysis of molecular variance demonstrated that the genetic variation between individual isolates was 72%, but only 2.3% when isolates from different regions were pooled. Both these observations suggest minimal genetic sub-structuring relative to geographical origin. Linkage disequilibrium was observed between pairs of loci within populations, as in certain Ugandan T. parva populations. A novel observation was that disequilibrium was also detected between alleles at three individual pairs of VNTR loci when isolates from the three regional meta-populations were pooled for analysis.     

Masking of sperm maturation antigen by sialic acid in the epididymis of the mouse. An immunohistochemical study

Sperm antigen expression during epididymal transit was examined in 4- to 16-week-old intact and castrated ICR mice, using the avidin-biotin complex (ABC) immunohistochemical method with monoclonal antibody T21 against a flagellar surface antigen. On untreated sections, the antigen was first expressed weakly on sperm in the proximal part of the corpus epididymis, and intraluminal components were stained in 4-week-old mice. Epididymal epithelial cells and their stereocilia, and cells in other reproductive organs were not stained. In contrast, on sections treated with neuraminidase, (1) the initial site of antigen appearance is a more proximal position in treated than in untreated sections, (2) stereocilia stained strongly, (3) the staining intensity of sperm and intraluminal components increased, and (4) some clear cells in the epithelium from the distal position of the caput to the corpus epididymis were stained. These results indicate that the antigen is produced by clear cells of the epididymal epithelium, that the antigenic determinant is masked initially by sialic acid residues, and that expression of the antigenic determinant on the sperm surface during epididymal maturation apparently involves desialylation.