Photoperiod- and temperature-dependent regulation of pupal beige/black polymorphism in the small copper butterfly, Lycaena phlaeas daimio Seitz

The small copper butterfly, Lycaena phlaeas daimio, has pupal beige/black polymorphism, the development of which is found to be controlled in an apparent association with the development of adult seasonal polymorphism (spring and summer morphs) by photoperiod and temperature in the larval stages. That is, the pupae of beige and black types developed under long-day and short-day conditions tend to develop into brown-winged and red-winged adults, respectively. In addition, a large proportion of long-day pharate pupae chilled at 4 degrees C for 5 days were observed to develop into pupae whose head-thoracic complexes and abdomens were judged to be of the black and intermediate types, respectively. They developed into adults with redder wings as compared to those obtained from unchilled pupae. The results indicate that the physiological mechanism underlying the photoperiodic control of the development of adult seasonal polymorphism may also play a significant role in the determination of pupal beige/black polymorphism in L. phlaeas daimio. Furthermore, cuticle melanization was found to be induced in the head-thoracic complexes of pupae by chilling of the pharate pupae. Melanization of pupal cuticle seems to occur in a close association with the development of reddish-winged adults.     

Morphological differences in nuclear materials released from hamster sperm heads at an early stage of incorporation into immature oocytes,mature oocytes,or fertilized eggs

To elucidate the effects of ooplasmic factors on the early morphological changes in hamster sperm heads within the ooplasm, immature ovarian oocytes at the germinal vesicle stage (GV oocytes), ovulated fully mature oocytes, and fertilized eggs at anaphase II or the pronuclear stage (PN eggs) were examined in detail 15–30 min after insemination or reinsemination. Thin-sectioning studies demonstrated distinct materials released from the sperm nucleus over the entire postacrosomal nuclear surface immediately after disappearance of the sperm nuclear envelope. The release occurred in all of the oocytes and eggs prior to or even in the absence of subsequent chromatin decondensation. Depending upon the stage of the penetrated oocyte or egg, however, the materials varied in morphology: several hemispherical projections of amorphous material within mature oocytes; a number of electron-dense globules within GV oocytes and PN eggs; and both forms within eggs at anaphase II-telophase II. These observations and the fact that only the release of the amorphous material was accompanied by sperm chromatin decondensation indicate that this release was the initial process of chromatin decondensation, whereas the release of the globules resulted from a deficiency or lack of ooplasmic factors affecting the sperm nucleus. Restriction of the release in both forms of material to the late meiotic phase suggests changes in the factors associated with progression of meiosis. To approach an understanding of the mechanism of successful decondensation of sperm chromatin, the ooplasmic factors considered responsible for the stage-dependent release of nuclear materials are discussed. © 1996 Wiley-Liss, Inc.     

Subunit IV (Mr = 14,384) of the cytochrome b-c1 complex from Rhodobacter sphaeroides. Cloning, DNA sequencing, and ubiquinone binding domain.

The Rhodobacter sphaeroides gene encoding subunit IV of the cytochrome b-c1 complex (fbcQ) was cloned and sequenced. The fbcQ cistron is 372 base pairs long and encodes 124 amino acid residues. The molecular mass of subunit IV, deduced from the nucleotide sequence, is 14,384 Da. A hydropathy plot of the predicted amino acid sequence revealed only one transmembrane helix; it is near the C-terminal end. The 3-azido-2-methyl-5-methoxy-6-(3,7-dimethyl[3H]octyl)-1,4-benzoquinone ([3H]azido-Q)-labeled subunit IV was isolated from the [3H]-azido-Q-treated cytochrome b-c1 complex. A ubiquinone-binding peptide was obtained by digesting the labeled subunit IV with V8 protease followed by high performance liquid chromatography separation. Amino acid analysis and partial N-terminal sequencing of this ubiquinone-binding peptide revealed that it corresponded to residues 77-124 of subunit IV. Based on the hydropathy profile and predicted tendency to form alpha-helices and beta-sheets, we propose a structural model for subunit IV. In this model the ubiquinone-binding domain is located near the surface of the membrane.     

Effects of polyamine hydrochlorides and salts on phosphoprotein phosphatase.

Polyamine hydrochlorides, NaCl and magnesium acetate stimulated the enzymatic dephosphorylation of phosphorylated H2B histone by two forms (large form, mol. wt. 250 000; small form, mol. wt. 30 000) of a pig heart phosphoprotein phosphatase (phosphoprotein phosphohydrolase, EC 3.1.3.16). These ionic compounds stimulated the large form of the enzyme 5--9-fold but stimulated the small form of theenzyme only 2-fold. With phosphorylated H2B histone as substrate, these effectors caused an increase in both Km and V values of the two forms of the enzyme. On the other hand, when a tryptic phosphodecapeptide derived from phosphorylated H2B histone was used as substrate, these effectors were always inhibitory apparently non-competitively with respect to the substrate. Using phosphorylated H1 histone as substrate, these effectors stimulated the large form of the enzyme 2-fold but inhibited the small form. With phosphorylase a as substrate, the reactions were also inhibited by these effectors irrespective of the enzyme employed. With respect to phosphorylase a, this inhibition was apparently of a competitive type for the large form and a non-competitive type for the small form of the enzyme.     

Regulating microtubule properties by modifying their organizing minus ends.

In the November 2001 issue of Developmental Cell, Vogel et al. describe that the budding yeast gamma-tubulin, Tub4p, is phosphorylated at a conserved tyrosine in G1 phase of the cell cycle. The results suggest that gamma-tubulin phosphorylation regulates the number and dynamics of microtubules.     

Zipper interacting protein kinase (ZIPK): function and signaling

Zipper interacting protein kinase (ZIPK), also known as death associated protein kinase 3, is a serine/threonine kinase that mediates variety of cell functions. The major biologic function of ZIPK is considered to be the regulation of apoptosis and smooth muscle contraction. Recently, several other functions of ZIPK have been gradually clarified. In this review article, we summarized the recent findings on ZIPK function and ZIPK-related cell signaling. We propose that ZIPK is a potential future target for the development of pharmaceutical therapy for cancer as well as cardiovascular diseases.     

Molecular design of N-linked tetravalent glycosides bearing N-acetylglucosamine,N,N′-diacetylchitobiose and N-acetyllactosamine: Analysis of cross-linking activities with WGA and ECA lectins

Two types of nonspacer- and spacer-N-linked tetravalent glycosides bearing N-acetylglucosamine (GlcNAc), N,N′-diacetylchitobiose [(GlcNAc)₂] and N-acetyllactosamine (LacNAc) were designed and prepared as glycomimetics. The interactions of wheat germ (Triticum vulgaris) agglutinin (WGA) and coral tree (Erythrina cristagalli) agglutinin (ECA) with a series of tetravalent glycosides and related compounds were studied using a hemagglutination inhibition assay, a precipitation assay, double-diffusion test, and an optical biosensor based on surface plasmon resonance (SPR). The tetravalent glycosides were found to be capable of binding and precipitating the lectins as tetravalent ligands. Strong interactions with WGA, due to a combination of multivalency effects and spacer effects, were observed for tetravalent glycosides bearing flexible tandem GlcNAc. The chelate effect leads to large rate enhancement for the tetravalent system with favorable orientation of ligands. Our simple strategy produced multivalent glycosides with strong cross-linking activity for lectin as a specific coagulant.     

Regression by ACE inhibition of arteriosclerotic changes induced by chronic blockade of NO synthesis in rats

We previously reported that chronic inhibition of nitric oxide (NO) synthesis with N(omega)-nitro-L-arginine methyl ester (L-NAME) induces vascular inflammation at week 1 and produces subsequent arteriosclerosis at week 4 and that cotreatment with an angiotensin-converting enzyme (ACE) inhibitor prevents such changes. In the present study, we tested the hypothesis that treatment with an ACE inhibitor after development of vascular inflammation could inhibit arteriosclerosis in rats. Wistar-Kyoto rats were randomized to four groups: the control group received no drugs, the 4wL-NAME group received L-NAME (100 mg x kg(-1) x day(-1)) for 4 wk, the 1wL + 3wNT group received L-NAME for 1 wk and no treatment for the subsequent 3 wk, and the 1wL + 3wACEI group received L-NAME for 1 wk and the ACE inhibitor imidapril (20 mg x kg(-1) x day(-1)) for the subsequent 3 wk. After 4 wk, we observed significant arteriosclerosis of the coronary artery (medial thickening and fibrosis) and increased cardiac ACE activity in the 1wL + 3wNT group as well as in the 4wL-NAME group, but not in the 1wL + 3wACEI group. In a separate study, we examined apoptosis formation and found that posttreatment with imidapril (20 mg x kg(-1) x day(-1)) or an ANG II AT1-receptor antagonist, CS-866 (5 mg x kg(-1) x day(-1)), induced apoptosis (TdT-mediated nick end-labeling) in monocytes and myofibroblasts appearing in the inflammatory lesions associated with a clear degradation in the heart (DNA electrophoresis). In conclusion, treatment with the ACE inhibitor after 1 wk of L-NAME administration inhibited arteriosclerosis by inducing apoptosis in the cells with inflammatory lesions in this study, suggesting that increased ANG II activity inhibited apoptosis of the cells with inflammatory lesions and thus contributed to the development of arteriosclerosis.     

Screening of alpha-helical peptide ligands controlling a calcineurin-phosphatase activity

In this paper, we describe an application of 202-membered fluorescently labeled peptide library designed to take an alpha-helix secondary structure. As a proof-of-concept experiment, a calmodulin (CaM)/calcineurin (Cn) pair was chosen to screen alpha-helical peptide ligands that tightly bind to CaM and also control enzymatic functions of Cn. Three peptides were successfully selected from the library by assaying Cn-phosphatase activities and peptide-CaM interactions (dual check process). The strategy using a designed peptide library shows real promise as a peptide-based high-throughput screening system.