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991.
Zayas-Pérez H Tello-Solís SR González-Márquez H Bonilla-González E Mendoza-Hernández G Betancourt-Rule M 《Protein and peptide letters》2005,12(3):299-303
We have purified and characterized pig and bovine milk lactadherins. Studies by circular dichroism spectroscopy indicate that the two proteins present a similar folding pattern. Results have been discussed in terms of their affinity for pig zona pellucida in order to use these proteins as analogs of pig sperm lactadherin in gamete studies. 相似文献
992.
dos Santos JI Takeda AA Marchi-Salvador DP Soares AM Fontes MR 《Protein and peptide letters》2005,12(8):819-822
BnSP-7 and BnSP-6, two Lys49-phospholipase A2 isolated from Bothrops neuwiedi pauloensis snake venom, were co-crystallized with alpha-tocopherol and X-ray diffraction data were collected for both complexes (2.2 and 2.6 A). A new "alternative" quaternary conformation for these two complexes compared with all other dimeric Lys49-PLA2 has been observed. 相似文献
993.
González-Coloma A Guadaño A Tonn CE Sosa ME 《Zeitschrift für Naturforschung. C, Journal of biosciences》2005,60(11-12):855-861
To validate the potential as added-value resources of Asteraceae and Labiatae species of Argentinean semi-arid lands, we have selected 13 of their major terpenoids belonging to several chemical classes and tested their insect antifeedant and toxic activity on the herbivorous insects Spodoptera littoralis and Leptinotarsa decemlineata. The antifeedant effects of the test compounds were structure- and species-dependent. The most active antifeedant to L. decemlineata was the eudesmane sesquiterpene gamma-costic acid (13), followed by the labdane diterpene 2alpha,3alpha-dihydroxycativic acid (8), the clerodane diterpenes 6-acetylteucjaponin B (5), bacchotricuneatin A (1), bartemidiolide (7), butanolide (4), and the sesquiterpenes ilicic acid (11) and tessaric acid (10) (eudesmane and eremophilane type, respectively). S. littoralis was only affected by the clerodanes and showed the strongest response to salviarin (3) and 5, followed by hawtriwaic acid (6) and 12-epi-bacchotricuneatin A (2). Orally injected S. littoralis larvae were negatively affected by 5. Most of the diterpenes had selective cytotoxic effects to insect-derived Sf9 cells with the clerodane 1 being the most active, followed by the eudesmane costic acid (12), the only cytotoxic sesquiterpene. None of these compounds was cytotoxic to mammalian CHO cells. 相似文献
994.
Lange BM Kirfel G Gestmann I Herzog V González C 《Histochemistry and cell biology》2005,124(3-4):325-334
Experimental approaches in Drosophila melanogaster over the last 20 years have played a fundamental role in elucidating the function, structure and molecular composition of
the centrosome. However, quantitative data on the structure and function of the Drosophila centrosome are still lacking. This study uses, for the first time, whole mount electron microscopy in combination with negative
staining on isolated centrosomes from the early Drosophila embryos to analyze its dimensions, structure and capacity to nucleate microtubules in vitro. We show that these organelles
are on average 0.75 μm in diameter and have abundant pericentriolar material which often appears fibrillar and with bulbous
protrusions. Corresponding to the abundant pericentriolar material, extensive microtubule nucleation occurs. Quantification
of the number of microtubules nucleated showed that 50–300 active nucleation sites are present. We examined via electron microscopy
immunogold labeling the distribution of γ-tubulin, CNN, Asp and the MPM-2 epitopes that are phosphorylated through Polo and
the Cdk1 kinase. The distribution of these proteins is homogeneous, with the MPM-2 epitopes exhibiting the highest density.
In contrast, centrosomal subdomains are identified using a centriole marker to relate centrosome size to the centriole number
by electron microscopy. In conclusion, we present a clear-cut technique assaying and quantifying the microtubule nucleation
capacity and antigen distribution complementing molecular studies on centrosome protein complexes, cell organelle assembly
and protein composition. 相似文献
995.
996.
Effect of cryopreservation on fusion efficiency and in vitro development into blastocysts of bovine cell lines used in somatic cell cloning 总被引:2,自引:0,他引:2
Hayes O Rodríguez LL González A Falcón V Aguilar A Castro FO 《Zygote (Cambridge, England)》2005,13(4):277-282
The outcome of the process of cloning by nuclear transfer depends on multiple factors that affect its efficiency. Donor cells should be carefully selected for their use in somatic nuclear transfer, and the protocols used for keeping frozen cell banks are of cardinal importance. Here we studied the effect of two protocols for freezing donor cells on fusion rate and development into blastocysts. Our hypothesis is that freezing affects cell membranes in a way that interferes with the fusion process upon cloning but without hampering normal cell development in vitro. We found that freezing cell lines without controlling the cooling rate gives lower yields in the fusion step and in the final development into blastocysts, compared with cells frozen with a controlled cooling rate of approximately 1 degrees C/min. Transmission electron microscopy of the cells subjected to different freezing procedures showed major damage to the cells frozen with a non-controlled protocol. We conclude that freezing of donor cells for cloning is a critical step in the procedure and should be monitored carefully using a method that allows for a step-wise, controlled cooling rate. 相似文献
997.
González R Collado I de Uralde BL Marcos A Martín-Cabrejas LM Pedregal C Blanco-Urgoiti J Pérez-Castells J Fernández MA Andis SL Johnson BG Wright RA Schoepp DD Monn JA 《Bioorganic & medicinal chemistry》2005,13(23):6556-6570
The synthesis of a series of C3'-cis-substituted carboxycyclopropyl glycines bearing a wide variety of functional groups is described, and the structure-activity relationship for this series as agonists of group II metabotropic glutamate receptors is reported. 相似文献
998.
999.
Mammalian cyclin-dependent kinases 总被引:15,自引:0,他引:15
1000.