钙离子在蟾蜍卵母细胞成熟分裂过程中的作用

缺钙处理的中华大蟾蜍卵母细胞,在孕酮作用下,仍能显示与恢复成熟分裂有关的早期启动变化,即卵内cAMP含量下降。但在缺钙条件下,孕酮不能促使卵母细胞进一步产生具有生物活性的促成熟因子,这可能与缺钙条件下卵母细胞内蛋白质磷酸化反应普遍低下有关。在外环境中有足量钙离子的条件下,即使无孕酮刺激,二价阳离子载体A_(23187)亦能诱发卵母细胞GVBD。这些结果无疑证明外源钙离子内流,以及由此可能导致的卵内游离钙离子增加,与卵母细胞恢复和完成成熟分裂有密切关系。     

Circuit for the electromanipulation of plant protoplasts

An electric circuit for plant protoplast manipulation is described. The circuit used readily available materials and was designed for use in teaching. This integrated circuit can be placed in a single small box with controls for the aligning voltage, the aligning frequency, the pulse voltage, and the pulse timing. The circuit can be supplied by any suitable source of dc power and can be easily altered for individual requirements. The circuit, as presented here, can be assembled for less than $250.     

Accumulation of CK-MM is impaired in innervated and contracting cultured muscle fibers of Duchenne muscular dystrophy patients

No specific abnormalities have been reproducibly manifested in aneurally cultured muscle of Duchenne muscular dystrophy (DMD) patients. We now report that the accumulation of the muscle-"specific" isozyme of creatine kinase (CK-MM) was significantly and preferentially impaired in long-term innervated contracting muscle fibers cultured from 4 DMD patients (DMD-InnCMFs) compared to: i) their noninnervated sister-cultured muscle fibers, and ii) innervated contracting control cultured human muscle fibers (Control-InnCHMFs). Accumulation of other muscle-"specific" isozymes (MSIs), viz. glycogen phosphorylase, phosphoglycerate mutase, and lactic dehydrogenase, was not significantly impaired. We have not observed preferentially-impaired CK-MM accumulation in any Control-InnCHMFs from 22 patients (children and adults) with a variety of neuromuscular diseases. There was no apparent difference between DMD-InnCMFs and Control InnCHMFs regarding: acceptance of innervation; neuronally-driven, virtually continuous muscle-fiber contractions; characteristic myofiber organization by phase-contrast microscopy, and increased longevity of the innervated fibers.     

The two binding sites for DCMU in Photosystem II

Measurements on the fluorescence induction of Triton X-100 extracted Photosystem II (PSII) particles confirmed the existence of the two sites of inhibition in PSII for the herbicide DCMU. The two sites were located on the reducing and oxidizing sides of PSII, respectively. The inhibition on the oxidizing side, unlike that on the reducing side which was of the "none or all" type, was found only to slow down the electron donation at low concentrations of DCMU. The results also suggested that the inhibitions of DCMU at these two sites were mutually exclusive, i.e., the binding on one site prevented the binding on the other site.     

Mixed-mode hydrophobic ion exchange for the separation of oligonucleotides and DNA fragments using HPLC

Hydrophobic anion exchangers were formed by cobonding both ionic and hydrophobic ligands to silica gel. These phases were used to separate single-stranded oligonucleotides and double-stranded DNA restriction fragments. By varying the ratio of n-octyldimethylsilane and either 3-chloropropyldimethylsilane or 4-chlorobutyldimethylsilane added during silanization a series of mixed-ligand or mixed-mode stationary phases was created. Concentration and ratio of bonded ligands were determined using a new gas chromatography fluorination method. Total ligand coverage was found to approach 2.1 ligands nm-2 for n-octyldimethylsilane. Bonding reproducibility for mixed-mode phases was good. Nucleic acid separations were achieved under gentle mobile phase conditions by using the stationary phase as an easily modifiable variable.     

Potentialities of induced pluripotent stem (iPS) cells for treatment of diseases

Induced pluripotent stem (iPS) cell research has been growing a new height throughout the world due to its potentialities in medical applications. We can explore several therapeutic applications through the iPS cell research. In this review, we have first discussed the development of iPS cells, reprogramming factors, and effectiveness of iPS cells. Then we have emphasized the potential applications of iPS cells in pharmaceutical and medical sectors, such as, study of cellular mechanisms for spectrum of disease entities, disease-specific iPS cell lines for drugs discovery and development, toxicological studies of drugs development, personalized medicine, and regenerative medicine.     

1H, 13C and 15N assignments of a camelid nanobody directed against human α-synuclein

Nanobodies are single chain antibodies that are uniquely produced in Camelidae, e.g. camels and llamas. They have the desirable features of small sizes (Mw < 14 kDa) and high affinities against antigens (Kd ~ nM), making them ideal as structural probes for biomedically relevant motifs both in vitro and in vivo. We have previously shown that nanobody binding to amyloidogenic human lysozyme variants can effectively inhibit their aggregation, the process that is at the origin of systemic amyloid disease. Here we report the NMR assignments of a new nanobody, termed NbSyn2, which recognises the C-terminus of the intrinsically disordered protein, human α-synuclein (aS), whose aberrant self-association is implicated in Parkinson’s disease.     

CCL5/CCR5 axis promotes the motility of human oral cancer cells

CCL5 (previously called RANTES) is in the CC‐chemokine family and plays a crucial role in the migration and metastasis of human cancer cells. On the other hand, the effect of CCL5 is mediated via CCR receptor. RT‐PCR and flow cytometry studies demonstrated CCR5 but not CCR1 and CCR3 mRNA in oral cancer cell lines, especially higher in those with high invasiveness (SCC4) as compared with lower levels in HSC3 cells and SCC9 cells. Stimulation of oral cancer cells with CCL5 directly increased the migration and metalloproteinase‐9 (MMP‐9) production. MMP‐9 small interfering RNA inhibited the CCL5‐induced MMP‐9 expression and thereby significantly inhibited the CCL5‐induced cell migration. Activations of phospholipase C (PLC), protein kinase Cδ (PKCδ), and NF‐κB pathways after CCL5 treatment was demonstrated, and CCL5‐induced expression of MMP‐9 and migration activity was inhibited by the specific inhibitor of PLC, PKCδ, and NF‐κB cascades. In addition, migration‐prone sublines demonstrate that cells with increasing migration ability had more expression of MMP‐9, CCL5, and CCR5. Taken together, these results indicate that CCL5/CCR5 axis enhanced migration of oral cancer cells through the increase of MMP‐9 production. J. Cell. Physiol. 220: 418–426, 2009. © 2009 Wiley‐Liss, Inc.     

Heritability and social brood effects on personality in juvenile and adult life‐history stages in a wild passerine

How has evolution led to the variation in behavioural phenotypes (personalities) in a population? Knowledge of whether personality is heritable, and to what degree it is influenced by the social environment, is crucial to understanding its evolutionary significance, yet few estimates are available from natural populations. We tracked three behavioural traits during different life‐history stages in a pedigreed population of wild house sparrows. Using a quantitative genetic approach, we demonstrated heritability in adult exploration, and in nestling activity after accounting for fixed effects, but not in adult boldness. We did not detect maternal effects on any traits, but we did detect a social brood effect on nestling activity. Boldness, exploration and nestling activity in this population did not form a behavioural syndrome, suggesting that selection could act independently on these behavioural traits in this species, although we found no consistent support for phenotypic selection on these traits. Our work shows that repeatable behaviours can vary in their heritability and that social context influences personality traits. Future efforts could separate whether personality traits differ in heritability because they have served specific functional roles in the evolution of the phenotype or because our concept of personality and the stability of behaviour needs to be revised.     

Subcellular localization of mannose 6-phosphate glycoproteins in rat brain.

The intracellular transport of soluble lysosomal enzymes relies on the post-translational modification of N-linked oligosaccharides to generate mannose 6-phosphate (Man 6-P) residues. In most cell types the Man 6-P signal is rapidly removed after targeting of the precursor proteins from the Golgi to lysosomes via interactions with Man 6-phosphate receptors. However, in brain, the steady state proportion of lysosomal enzymes containing Man 6-P is considerably higher than in other tissues. As a first step toward understanding the mechanism and biological significance of this observation, we analyzed the subcellular localization of the rat brain Man 6-P glycoproteins by combining biochemical and morphological approaches. The brain Man 6-P glycoproteins are predominantly localized in neuronal lysosomes with no evidence for a steady state localization in nonlysosomal or prelysosomal compartments. This contrasts with the clear endosome-like localization of the low steady state proportion of mannose-6-phosphorylated lysosomal enzymes in liver. It therefore seems likely that the observed high percentage of phosphorylated species in brain is a consequence of the accumulation of lysosomal enzymes in a neuronal lysosome that does not fully dephosphorylate the Man 6-P moieties.