Further evidence and biological significance for non-random localization of the centromere on mammalian chromosomes

A further quantitative analysis of the localization of the centromere on chromosomes was made using 16,817 individual chromosomes obtained from 723 mammalian species. Centromeric position was expressed quantitatively by the size of short arms as per cent weight (S_w) relative to the X-containing haploid set. When the class interval of S_w was 0·1 instead of the previous 0·2 (Imai, 1975), the frequency distribution of S_w showed an uneven (W-shaped) pattern with two distinct antimodes lying at S_w 0·6 (reconfirmation) and 0·1 (new finding). Two hypotheses, that are not mutually exclusive, are proposed to explain the non-random distribution of centromere position. One is that there are three structurally different short arms consisting of (1) centromere, (2) constitutive heterochromatin (as determined by C-banding), and (3) euchromatin, each arm-type being approximately characterized by the size of short arms (S_w) as S_w < 0·1, 0·1 ? S_w ? 0·6 and S_w > 0·6. The other possibility is concerned with an “orthogenetical” change of chromosome morphologies. When the chromosomes with S_w < 0·1, 0·1 ? S_w ? 0·6 and S_w > 0·6 are denoted as telocentric (T), acrocentric (A), and meta-, submeta- and subtelocentric (M, SM & ST), it was suggested that the chromosome morphologies tend to change orthogenetically (in a statistical sense) from T to M, SM & ST via A-chromosomes by rearrangements such as tandem growth of constitutive heterochromatic, pericentric inversions, and centric fusions.     

Histochemical studies on the morphology of the golgi apparatus and on the enzymes of carbohydrate metabolism in various nuclei of the rat mesencephalon

Summary Detailed histochemical studies have been conducted on the distribution of various enzymes such as thiamine pyrophosphatase, α-glucan phosphorylase, hexokinase, glucose-6-phosphate dehydrogenase, aldolase, lactate dehydrogenase and succinate dehydrogenase in various components of the nucleusEdinger-Westphali, nucleus n. oculomotorii, nucleus ruber and nucleus niger of healthy adult male Wistar strain rats. The thiamine pyrophosphatase reaction showed the morphological patterns of the Golgi apparatus characteristic for each nucleus. The Golgi apparatus was well developed in the nucleusEdinger-Westphali, composing a network of highly fenestrated plates in the nucleus n. oculomotorii and nucleus ruber, and a simple network in the nucleus niger. These results indicate that the former three nuclei need a rich energy supply and argue against the possibility that the four nuclei have a secretory role. The neurons of the nucleusEdinger-Westphali may derive their energy mainly from glucose of the circulating blood, but glial cells may serve as energy donators to the neurons in the pars compacta of the nucleus niger, and the neurons of the other nuclei may derive energy from both sources. These conclusions are consistent with the morphological patterns of the Golgi apparatus. It is suggested that the neurons of the nucleusEdinger-Westphali, nucleus n. oculomotorii, nucleus ruber and of the pars lateralis of the nucleus niger may be equipped almost equally with the Embden-Meyerhof pathway and with the hexose monophosphate shunt. But, the hexose monophosphate shunt is dominant in the pars compacta of the nucleus niger. It is also suggested that the pattern of distribution of succinate dehydrogenase may parallel that of lactate dehydrogenase. The nucleus n. oculomotorii, and nucleus ruber have a higher level of oxidative metabolism than the nucleusEdinger-Westphali and the nucleus niger. The nucleusEdinger-Westphali may be representative of autonomic nuclei with low oxidative metabolism whereas the nucleus n. oculomotorii may represent motor nuclei with high oxidative metabolism. Predominance of hexose monophosphate shunt, intense hexokinase reaction around the neurons, and weak activity of succinate dehydrogenase indicate that the pars compacta of the nucleus niger belongs to the category of “exceptional nuclei”.     

Freeze-etching studies on ultrastructural changes of endothelial cells in the thyroid of normal,TSH-treated and Thyradin-treated mice

Summary Freeze-etching images of the capillary endothelium in the thyroid of normal, TSH-treated and Thyradin (powdered thyroid)-treated mice were examined. Numerous pores represent vesicular stomata or fenestrations. The number of the pores and their population density are increased in TSH-treated mice, and decreased in Thyradin-treated animals. In addition, the width of the parajunctional zone and of the flat ray free from endothelial pores is smaller in TSH-treated mice and larger in Thyradin-treated animals. These facts indicate that the number of endothelial pores changes according to the functional activity of the gland.Supported by a grant from the Japanese Educational Ministry     

Thermodynamical studies of oxygen equilibrium of hemoglobin. Nonuniform heats and entropy changes for the individual oxygenation steps and enthalpy-entropy compensation.

Precise oxygen equilibrium curves of human adult hemoglobin were determined by the automatic recording method at several temperatures in the presence and absence of 2,3-diphosphoglycerate (DPG) or inositol hexaphosphate (IHP) with 0.05 M 2,2-bis(hydroxymethyl)-2,2',2'-nitrolotriethanol (bis-tris) buffers (pH 7.4) containing 0.1 M Cl-. The equilibrium data were analyzed according to the Adair scheme, and the heats, deltaHi (i = 1,2,3,4) and the entropy changes, deltaSi (i = 1,2,3,4), for the individual oxygenation steps were obtained. The shape of the equilibrium curve varies on temperature changes whether DPG or IHP is present or absent. In consequence, the deltaHi value depends on i and on the presence of DPG and IHP. Behavior of deltaSi is similar to that of deltaHi. The similar behavior of deltaHi and deltaSi resulted in a compensation phenomenon. The contribution of T cdeltaSi to the free energy change is compensated by the contribution of deltaHi at the first three oxygenation steps but not at the fourth step, and for i = 1,2, and 3 changes of T cdeltaSi value upon the addition of DPG and IHP are compensated by accompanied changes of deltaHi value, where T c (= 260 K) is the compensation temperature. A major part of both the enthalpy-entropy compensation and nonuniformity of deltaHi and deltaSi appears to be attributable to contributions of the oxygen-linked binding of Cl-, DPG and IHP, by hemoglobin. The present results do not necessarily support the earlier idea of Wyman that the cooperative oxygenbinding is essentially an entropy effect.     

Effect of polyanions and polycations on adenosine 3',5'-monophosphate-binding and protein kinase activity.

Histone, protamine, poly-L-arginine, and poly-L-lysine enhance the binding of adenosine 3′,5′-monophosphate (cyclic AMP) to rat liver cyclic AMP-dependent protein kinase as determined by Millipore filtration assay. Poly-L-glutamic acid and poly-L-aspartic acid suppress cyclic AMP-binding stimulated by histone. Poly-L-glutamic acid and poly-L-aspartic acid are effective against protein kinase and result in decrease in initial reaction velocity when histone is used as a protein substrate. Incubation of cyclic AMP-dependent protein kinase with 6 μg poly-L-glutamic acid produces half-maximal inhibition of cyclic AMP-dependent protein kinase when 30 μg histone is used as substrate.     

Experimental Approach Reveals the Role of alx1 in the Evolution of the Echinoderm Larval Skeleton

Over the course of evolution, the acquisition of novel structures has ultimately led to wide variation in morphology among extant multicellular organisms. Thus, the origins of genetic systems for new morphological structures are a subject of great interest in evolutionary biology. The larval skeleton is a novel structure acquired in some echinoderm lineages via the activation of the adult skeletogenic machinery. Previously, VEGF signaling was suggested to have played an important role in the acquisition of the larval skeleton. In the present study, we compared expression patterns of Alx genes among echinoderm classes to further explore the factors involved in the acquisition of a larval skeleton. We found that the alx1 gene, originally described as crucial for sea urchin skeletogenesis, may have also played an essential role in the evolution of the larval skeleton. Unlike those echinoderms that have a larval skeleton, we found that alx1 of starfish was barely expressed in early larvae that have no skeleton. When alx1 overexpression was induced via injection of alx1 mRNA into starfish eggs, the expression patterns of certain genes, including those possibly involved in skeletogenesis, were altered. This suggested that a portion of the skeletogenic program was induced solely by alx1. However, we observed no obvious external phenotype or skeleton. We concluded that alx1 was necessary but not sufficient for the acquisition of the larval skeleton, which, in fact, requires several genetic events. Based on these results, we discuss how the larval expression of alx1 contributed to the acquisition of the larval skeleton in the putative ancestral lineage of echinoderms.     

The Anthocyanins in the Petals of White Peach (Prunus percica SlBE et ZUCC var. vulgaris MAXIM.)

Two kinds of anthocyanin were isolated from the petals of white peach and examined by paper chromatographic and spectral analyses. The results showed that one of them is crysanthemin and the other is a derivative of chrysanthemin which has not been isolated from peaches previously.     

Influence of surface anesthesia on the pressure pain threshold measured with different-sized probes

Transcutaneous pressure with pressure probes of arbitrary diameters have been commonly used for measuring the threshold and magnitude of muscle pain, yet this procedure lacks scientific validation. To examine the valid probe dimensions, we conducted physiological experiments using 34 human subjects. Pin-prick pain, pressure pain threshold (PPT) to pressure probes of various diameters, heat pain threshold, and electrical pain threshold of deep tissues were measured before and after application of surface lidocaine anesthesia to the skin surface over the brachioradial muscle in a double-blinded manner. The anesthesia neither affected PPT with larger probes (diameters: 1.6 and 15?mm) nor increased electric pain threshold of deep structures, whereas it diminished pain count in pin-prick test and PPT with a 1.0?mm diameter probe, suggesting that mechanical pain thresholds measured with 1.6 and 15?mm probes reflect the pain threshold of deep tissues, possibly muscle. Pain thresholds to heat did not change after application of the anesthesia. These results suggest that larger pressure probes can give a better estimation of muscular pain threshold.