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.     

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.     

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.     

Filipin-sterol complexes in golden hamster sperm membranes with special reference to epididymal maturation

Summary The distribution of membrane filipin-sterol complexes (FSCs) was qualitatively surveyed on freeze-fracture replicas of spermatozoa from the male reproductive tract and ejaculates of golden hamster. In the head, the acrosomal plasma membrane showed the strongest filipin labeling on the principal segment, but it was absent in the quilt-like pattern areas. These latter were observed in both caput and corpus epididymal spermatozoa, but were absent in mature spermatozoa. The postacrosomal plasma membrane had few FSCs and both the outer and inner acrosomal membranes were always negative to filipin. The nuclear membrane of the principal segment was constantly filipinpositive. The nuclear membrane of the postacrosomal region had more FSCs than that of the principal segment, particularly in mature spermatozoa. Many linear, rod-like FSCs were observed on the postacrosomal nuclear membrane of mature spermatozoa, especially in the uterine spermatozoan samples. In the neck, the plasma membrane had only a few FSCs. The redundant nuclear membrane was slightly filipin-positive, while the membrane scroll of mature spermatozoa was heavily labeled. In the tail, the plasma membrane of both the middle and principal piece was moderately labeled.     

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.     

Spermatogenesis in animals as revealed by electron microscopy

Summary Testes of Bombyx mori Linné were fixed in buffered (pH 8.2) 1% OsO₄ or 3 % KMnO₄ and thin sections of the tissue, embedded in methacrylate or epoxy Epon resin, were studied under the electron or light microscope.At the late stage of differentiation of the spermatid, the nucleus shows an elongated conical contour, being composed of fine fibrillar elements. These fibrillar elements fixed in OsO₄ measure 100 to 130 Å in diameter, while those fixed with KMnO₄ are approximately 70 Å in diameter.It has been found for the first time in the spermiogenesis of the silkworm that two bands and a tubular structure develop in close proximity to one another and attached to the plasma membrane of the spermatid. The two bands fixed in OsO₄ are electron dense, but in the material fixed with KMnO₄, one of them, situated within the cell body, is as dense as that fixed in OsO₄, while the other, outside the cell body, is much less dense. These apparently novel apparatuses develop from the caudal nuclear region along the elongating spermatid, but the dense band intertwines with the acrosome in the apical region of the nucleus along the major axis of spermatid, while the tubular structure and the clear band reach far into the nutritive cell where the dense band and acre-some are not visible.A possible relationship between the tubular structure and the nutritive cell has been discussed.This study was supported by Grant GM-8327-03 from the United States Public Health Service.     

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.