Glass melt inclusion in clinopyroxene from Linqu Cenozoic basalt, Shandong Province, China

Melt inclusions or glasses usually occur in spinel- facies peridotitic xenoliths entrained in the global ba- salts[1―4], and olivine phenocrysts and/or xenocrysts carried in the intermediate-mafic volcanic rocks (such as basalts, basaltic andesites and h…     

Composition and conservation of the telomeric complex

The telomere is composed of telomeric DNA and telomere-associated proteins. Recently, many telomere-associated proteins have been identified, and various telomere functions have been uncovered. In budding yeast, scRap1 binds directly to telomeric DNA, and other telomere regulators (Sir proteins and Rif proteins) are recruited to the telomeres by interacting with scRap1. Cdc13 binds to the most distal end of the chromosome and recruits telomerase to the telomeres. In fission yeast and humans, TTAGGG repeat binding factor (TRF) family proteins bind directly to telomeric DNA, and Rap1 proteins and other telomere regulators are recruited to the telomeres by interacting with the TRF family proteins. Both organisms have Pot1 proteins at the most distal end of the telomere instead of a budding-yeast Cdc13-like protein. Therefore, fission yeast and humans have in part common telomeric compositions that differ from that of budding yeast, a result that suggests budding yeast has lost some telomere components during the course of evolution.     

Mitosis-specific phosphorylation causes 83K non-muscle caldesmon to dissociate from microfilaments

At mitosis in eukaryotic cells there are profound changes of shape and structure whose causes are almost entirely obscure. What is known is that there are changes in the organization of microfilaments, including the disassembly of microfilament bundles during prophases and the accompanying rounding-up of cultured cells; the formation of transient contractile rings during cytokinesis; and, subsequently, the reassembly of microfilament bundles and the respreading of the two daughter cells. As an initial step towards the biochemical understanding of these events, in which the disassembly and reassembly of microfilaments appear to play an important part, we searched for alterations of the molecular constitution of microfilaments during mitosis. We found that non-muscle caldesmon, a protein with a relative molecular mass (Mr) of 83,000 (83K) which binds to actin and calmodulin, is dissociated from microfilaments during mitosis, apparently as a consequence of phosphorylation. This process may contribute to the changes of shape and structure of cells in mitosis, as caldesmon inhibits actomyosin ATPase.     

Antagonism by thyrotropin-releasing hormone (TRH) of pentobarbital-induced hypothermia in rats with brain lesions

Anesthesia with a large dose of pentobarbital (55 mg/kg, i.p.) caused a sustained decrease in brain temperature (Tb), which was monitored with a probe placed in the midbrain reticular formation. The administration of TRH to the lateral ventricle antagonized this hypothermia. None of the acute surgeries examined in this paper (adrenal-demedullectomy, septal knife cuts, electrolytic lesions of the hypothalamus and midbrain knife cuts) had any essential effect on this antagonism by TRH. These results suggest that centrally-administered TRH exerts its effect on thermoregulation, at least in part, through brain structure(s) caudal to the midbrain.     

Inhibition of lipid peroxidation by diterpenoid fromPodocarpus nagi

A diterpenoid, totarol (1), fromPodocarpus nagi was evaluated as an antioxidant. This diterpenoid inhibited autoxidation of linoleic acid. Mitochondrial and microsomal lipid peroxidation induced by Fe(III)-ADP/NADH or Fe(III)-ADP/NADPH were also inhibited. Nagilactone E (2), a norditerpene lactone isolated from the same source, had no antioxidative activity. Furthermore, totarol protected red cells against oxidative hemolysis. This diterpene was shown to be effective in protecting biological systems against oxidative stresses.     

IGFBP-4 is an inhibitor of canonical Wnt signalling required for cardiogenesis

Insulin-like growth-factor-binding proteins (IGFBPs) bind to and modulate the actions of insulin-like growth factors (IGFs). Although some of the actions of IGFBPs have been reported to be independent of IGFs, the precise mechanisms of IGF-independent actions of IGFBPs are largely unknown. Here we report a previously unknown function for IGFBP-4 as a cardiogenic growth factor. IGFBP-4 enhanced cardiomyocyte differentiation in vitro, and knockdown of Igfbp4 attenuated cardiomyogenesis both in vitro and in vivo. The cardiogenic effect of IGFBP-4 was independent of its IGF-binding activity but was mediated by the inhibitory effect on canonical Wnt signalling. IGFBP-4 physically interacted with a Wnt receptor, Frizzled 8 (Frz8), and a Wnt co-receptor, low-density lipoprotein receptor-related protein 6 (LRP6), and inhibited the binding of Wnt3A to Frz8 and LRP6. Although IGF-independent, the cardiogenic effect of IGFBP-4 was attenuated by IGFs through IGFBP-4 sequestration. IGFBP-4 is therefore an inhibitor of the canonical Wnt signalling required for cardiogenesis and provides a molecular link between IGF signalling and Wnt signalling.     

四川蝙蝠核型的进一步研究

报道了含中国特有种大足鼠耳蝠(Myotis ricketti)在内的、四川地区6种蝙蝠的核型.菊头蝠科2种,即大耳菊头蝠(Rhinolophus macrotis),核型为2n=62,FN=60;云南菊头蝠(R.yunanensis),核型较为特殊,2n=46,FN=58.蹄蝠科1种,即普氏蹄蝠(Hipposideros pratti),核型为2n=32,FN=60;蝙蝠科鼠耳蝠属3种,即中华鼠耳蝠(Myotis chinensis),核型为2n=44,FN=50;大足鼠耳蝠为2n=44,FN=52;西南鼠耳蝠(M.altarium)为2n=44,FN=50.其中云南菊头蝠的核型为中国第1次报道.