Ultrastructural studies on the effects of hypergravity environment on the parathyroid glands in golden hamsters of different ages

The ultrastructure of the parathyroid glands of infantile, young, adult and senile golden hamsters subjected to a hypergravity environment was studied. In the parathyroid glands of 5-, 10- and 20-day-old, and 1- and 3-month-old golden hamsters exposed to a hypergravity environment, the Golgi complexes were significantly increased, and in 5-, 10- and 20-day-old, and 1- and 8-month-old animals exposed to a hypergravity environment, the cisternae of the granular endoplasmic reticulum appeared to be increased as compared to those of each control group. In addition, in centrifuged animals numerous prosecretory granules were observed in the Golgi areas, and many secretory granules were located in the peripheral cytoplasm. The ultrastructure of the parathyroid glands of 14-month-old centrifuged animals resembled that of 14-month-old control animals. These results suggest that the secretory activity of the parathyroid gland may be stimulated in infantile, young and adult golden hamsters subjected to a hypergravity environment and may not be stimulated in senile animals subjected to a hypergravity environment.     

Determination of dimethyl sulphide in blood and adipose tissue by headspace gas analysis

A method for the headspace analysis of dimethyl sulphide in blood and adipose tissue has been established. Blood (0.2 ml) or adipose tissue (0.5 g) with added dimethyl sulphide was sealed in a 10-ml vial using PTFE sheet to prevent escape of dimethyl sulphide from the headspace. Equilibration was performed at 60°C for 4 h, and 20 μl of gaseous phase sampled from the headspace was subjected to gas chromatography (with flame photometric detection). Calibration curves were prepared for the two samples. Linearity was observed in the range from 5–10 μg to 2 mg.     

Genetic polymorphism of the sixth component of complement (C6) in mice

Immunofixation after isoelectric focusing revealed two forms of mouse C6, C6A and C6M, both of which consist of two major protein bands and one or more acidic minor bands. They were distinguishable by their different isoelectric point (pI) ranges: C6M has more acidic pI ranges (pH < 6.2) than C6A (pH < 6.3). C6A was found in common inbred mice of Mus musculus domesticus, while C6M was found in inbred and wild mice of M. m. molossinus (Japanese wild mice, an Asian subspecies). Breeding experiments showed that these two forms of C6 were controlled by a single codominant autosomal locus. We propose the designation C-6 for this locus with two alleles, C-6 ^a and C-6 ^m , which encode for C6A and C6M, respectively. Linkage analysis indicated that the locus is not closely linked to the following loci: Idh-1, agouti, Amy-1, brown, Gpd-1, Mup-1, Pgm-2, Pgm-1, albino, Hbb, Es-1, Mod-1, Sep-1, Es-3, Igh-1, beige, Es-10, Sod-1, and C-3.     

The ATP-binding site in gamma subunit of phosphorylase kinase

To reveal the structure of the ATP-binding site(s) in rabbit muscle phosphorylase kinase, we modified the enzyme with adenosine polyphosphopyridoxals. Adenosine tri- and tetraphosphopyridoxals at micromolar concentrations effectively inactivated the enzyme in a time-dependent manner. Inactivation of the enzyme was accelerated by the addition of Ca2+ and Mg2+. Protection from inactivation was afforded by adenylyl beta,gamma-imidodiphosphate and ADP. In reversible inhibition kinetics, adenosine polyphosphopyridoxals as well as their reduced compounds (adenosine polyphosphopyridoxines) competed with ATP. These results suggest that adenosine polyphosphopyridoxals bind to the ATP-binding site(s) in phosphorylase kinase. When phosphorylase kinase was incubated with adenosine triphosphopyridoxal in the presence of Ca2+ and Mg2+, incorporation of the label into alpha, beta, and gamma subunits was observed. In the absence of both cations, larger amounts of the label were incorporated into all the subunits. Structural study on adenosine triphosphopyridoxal-modified sites in the gamma subunit (having a catalytic site) revealed that Lys-151 is mainly labeled. Based on the results of the present and other studies, it is suggested that the site around Lys-151 is involved in recognition of the substrate protein.     

Effects of anti-microtubule drugs onin vitro polymerization of tubulin from mung bean

Effects of anti-microbule drugs on tubulin polymerizationin vitro were investigated using purified mung bean (Vigna radiata) tubuli. Colchicine induced the formation of macrotubules at the relatively low concentration of 10 μM. and the appearance of corkscrew-like filaments from the ends of the macrotubules at concentrations of more than 100 μM. Vinblastine substantially inhibited polymerization at 1 μM and caused the formation of paracrystals at concentrations greater than 10 μM. Oryzalin inhibited polymerization at 1 μM partially and at 10 μM completely. Paracrystal formation was also induced by cremart at 10 μM, but these paracrystals appeared to be more rigid than those induced by vinblastine. Amiprophos methyl (APM), with a chemical configuration similar to cremart, substantially inhibited polymerization at 1 μM, but the formation of paracrystals was weak. Griseofulvin at 10 μMalso inhibited the polymerization of tubulin while at higher concentrations aggregates of helices were formed. Inhibition of polymerization by phenylcarbamate herbicides was more effective than that caused by benzimidazoylcarbamate fungicides. The effects of drugs onin vitro preformed (MTs) were also investigated. Colchicine and vinblastine showed identical effects to those on the polymerization process. Griseofulvin, cremart and APM induced only macrotubule formation while the other drugs tested had no major effects     

Context Analysis of Termination Codons in mRNA that are Recognized by Plant NMD

The above article was published in      

Synthesis and structure–activity relationships of N-(4-amino-2,6-diisopropylphenyl)-N’-(1,4-diarylpiperidine-4-yl)methylureas as anti-hyperlipidemic agents

Based on 1,4-diarylpiperidine-4-methylureas, a new class of ACAT inhibitors, we examined in the study the SAR of a series of compounds prepared by replacing the substituent at the three aromatic parts. Introduction of long alkoxy group onto the phenyl moiety at the B-part was effective in improving both the inhibitory activity for ACAT and the up-regulatory activity for LDL-R expression. Particularly, 3-hydroxypropoxy group (43) on the phenyl moiety of B-part led to improved solubility, while keeping both biological activities. Compound 43 inhibited ACAT activity with an IC₅₀ value of 18 nM, which is superior to that of a known ACAT inhibitor, CI-1011. In addition, compound 43 revealed an LDL-R up-regulatory activity comparable to that of SMP-797. We therefore expect this compound to be a novel ACAT inhibitor.     

Production of Yeast Cells from Methanol

Using immunochemical technique thermal denaturation of soybean 11S globulin, dissolved in different ionic strength solutions (µ=0~4.0) and heated at 100°C for 5 min, has been quantitatively studied. The curves of the percentage of antigenicity remaining were obtained as a function of salt concentration. The 11S globulin became strongly resistant to thermal denaturation with increasing both KCl and potassium phosphate. The stabilizing effect (in terms of percent antigenicity) was separated into three regions. At ionic strength below 0.7, potassium phosphate had no stabilizing effect while KCl had aslightly effect. The rise in stabilizing effect up to about 50%, near 1.0~1.5 µ, represented a second transition to a different denatured state which retains undissociated molecule. At rises up to 75~95%, near 2.5~3.5µ, a different conformational state resulted in which thermally denatured 11S globulin maintained almost intact native conformation after heating. The selection of an adequate ionic strength of protein solution has enabled preparation of thermally denatured 11S globulins which have desired-residual amounts of structured regions.     

Introduction of an Azido Group to the C-6 Position of Uridine by the Use of a 6-Iodouridine Derivative

Abstract

Nucleophilic addition-elimination reaction of azide ion to 6-iodo-2′,3′-O-isopropylidene-5′-O-methoxy-methyluridine proceeded under mild conditions to give a 6-azidouridine derivative.