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991.
Georges M. Pavlov Evguenija V. Korneeva Natalia P. Yevlampieva 《International journal of biological macromolecules》1994,16(6):318-323
The hydrodynamic characteristics of the polysaccharide pullulan (polymaltotriose) in water have been investigated and its molecular characteristics have been determined. Experimental values varied over the following ranges: velocity sedimentation coefficient (S): 0.9 < S < 11.2, translational diffusion coefficient (107 cm2 s−1): 1.1 < D < 14.7 and intrinsic viscosity (cm3 g−1): 6.7 < [η] < 164, which corresponds to a change in molecular weight (× 103) in the range 3.9 < MSD < 644. On the basis of analysis of the literature and our experimental data, excluded volume effects have been shown to have a prevailing influence on the chain length of these polysaccharides. The equilibrium rigidity and hydrodynamic chain diameter of pullulan were evaluated on the basis of the theory of hydrodynamic properties of a wormlike necklace, taking into account excluded volume effects. At low M (< 30 × 103) the translation friction data (in contrast to viscometric data) cannot be described in the framework of the theory of linear molecules. 相似文献
992.
1. Examining male residents of the Russian Far-East, changes in their heart rate structures and temperature variations on the hand surfaces under hypoxic and local cold factor were studied.
2. Reliable differences in statistical and spectral-wave indices of human heart rate and hand surface thermal pattern depending on the level of nonspecific resistance.
3. It is possible to select persons resistant to low temperature and oxygen deficiency by their heart rate responses to hypoxia and local cold impacts. 相似文献
993.
Marina Clemente Natalia Miguel VeronicaV. Lia Mariana Matrajt SergioO. Angel 《Genetica》2002,114(3):297-299
994.
Olga O. Nerusheva Natalia V. Dorogova Leonid V. Omelyanchuk 《Central European Journal of Biology》2009,4(4):452-460
Localization of a set of chimeric GFP proteins in D. melanogaster spermatogenesis has been studied. In the collection used, the proteins with detectable germ-line expression frequently occur
to be involved in mRNA maturation. According to the cellular localization, proteins fall into three groups, namely, the protein
Rtc1, involved in splicing, displays an exclusively nuclear localization; the proteins Squid (splicing and mRNA transport),
Pabp2 (polyadenylation), and Hrb98DE (splicing and mRNA transport) change their localization during germ-line development;
and the protein Imp (mRNA localization) is located exclusively in the cytoplasm. The distribution of Rtc1, Squid and Hrb98DE
in the spermatocyte nuclei is morphologically similar to the distribution of splicing bodies, the so-called splicing factor
compartments. The proteins Imp and Hrb98DE at the stage of elongation are localized to a specialized structure in the caudal
region of cyst; this region corresponds to the site of the highest synthetic activity in the cyst cells at this developmental
stage. 相似文献
995.
996.
Micha Turek Katarzyna Banasiak Magorzata Piechota Nilesh Shanmugam Matylda Macias Magorzata Alicja
liwiska Marta Niklewicz Konrad Kowalski Natalia Nowak Agnieszka Chacinska Wojciech Pokrzywa 《EMBO reports》2021,22(8)
Caenorhabditis elegans body wall muscles release vesicles called exophers that transport muscle‐synthesized yolk proteins to nourish the next generation. 相似文献
997.
Bunney TD Harris R Gandarillas NL Josephs MB Roe SM Sorli SC Paterson HF Rodrigues-Lima F Esposito D Ponting CP Gierschik P Pearl LH Driscoll PC Katan M 《Molecular cell》2006,21(4):495-507
Ras proteins signal to a number of distinct pathways by interacting with diverse effectors. Studies of ras/effector interactions have focused on three classes, Raf kinases, ral guanylnucleotide-exchange factors, and phosphatidylinositol-3-kinases. Here we describe ras interactions with another effector, the recently identified phospholipase C epsilon (PLCepsilon). We solved structures of PLCepsilon RA domains (RA1 and RA2) by NMR and the structure of the RA2/ras complex by X-ray crystallography. Although the similarity between ubiquitin-like folds of RA1 and RA2 proves that they are homologs, only RA2 can bind ras. Some of the features of the RA2/ras interface are unique to PLCepsilon, while the ability to make contacts with both switch I and II regions of ras is shared only with phosphatidylinositol-3-kinase. Studies of PLCepsilon regulation suggest that, in a cellular context, the RA2 domain, in a mode specific to PLCepsilon, has a role in membrane targeting with further regulatory impact on PLC activity. 相似文献
998.
Cadavid Isabel Cristina Giraldo Carlos E. Balbinott Natalia González Mailyn Adriana Uribe Sandra Inés de Boer Hugo J. 《Journal of plant biochemistry and biotechnology.》2022,31(4):938-952
Journal of Plant Biochemistry and Biotechnology - Solanum is the largest and most diverse genus of the Solanaceae family. The genus includes around 1,400 species, and almost a third belong to... 相似文献
999.
Antagonistic regulation of alpha-actinin alternative splicing by CELF proteins and polypyrimidine tract binding protein 总被引:6,自引:0,他引:6
The alpha-actinin gene has a pair of alternatively spliced exons. The smooth muscle (SM) exon is repressed in most cell types by polypyrimidine tract binding protein (PTB). CELF (CUG-BP and ETR3-like factors) family proteins, splicing regulators whose activities are altered in myotonic dystrophy, were found to coordinately regulate selection of the two alpha-actinin exons. CUG-BP and ETR3 activated the SM exon, and along with CELF4 they were also able to repress splicing of the NM (nonmuscle) exon both in vivo and in vitro. Activation of SM exon splicing was associated with displacement of PTB from the polypyrimidine tract by binding of CUG-BP at adjacent sites. Our data provides direct evidence for the activity of CELF proteins as both activators and repressors of splicing within a single-model system of alternative splicing, and suggests a model whereby alpha-actinin alternative splicing is regulated by synergistic and antagonistic interactions between members of the CELF and PTB families. 相似文献
1000.
Tatiana V. Burova Irina A. Golubeva Natalia V. Grinberg Alexander Ya. Mashkevich Valery Ya. Grinberg Anatoly I. Usov Luciano Navarini Attilio Cesro 《Biopolymers》1996,39(4):517-529
Thermally induced order-disorder conformational transition in succinoglycan was studied using the method of high-sensitivity differential scanning microcalorimetry within the range of polysaccharide concentrations from 0.1 to 3.5 mg mL−1 at NaCl concentrations 0, 0.01, and 0.1M. The positions and shapes of the excess heat capacity curves depended substantially on both the NaCl and polysaccharide concentrations. At low polysaccharide concentrations in salt-free solution the experimental curves were closely approximated by the two-state model suggesting the transition mechanism to be of the single helix-coil type. With increasing polysaccharide and/or NaCl concentration, the experimental curves changed significantly in symmetry, which indicated a changing transition mechanism. At high polysaccharide concentrations or in the presence of the salt, the order-disorder transition of succinoglycan was shown to include two stages: the cooperative dissociation of the helix dimer and subsequent two-state melting of the helix monomer. The dependence of thermodynamic parameters for the dissociation and melting of helix structures in succinoglycan on NaCl and polysaccharide concentrations was obtained by fitting the experimental excess heat capacity curves. The cooperativity parameter σ for the single helix-coil transition as well as the average length of the helix segment of succinoglycan were calculated. Some features of succinoglycan ordering in solution are discussed. © 1996 John Wiley & Sons, Inc. 相似文献