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排序方式: 共有668条查询结果,搜索用时 15 毫秒
61.
62.
Spooner DM Nuñez J Rodríguez F Naik PS Ghislain M 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2005,110(6):1020-1026
The modern cultivated potato was first recorded in Europe in 1562, but its area(s) of exportation has long been in dispute. Two competing hypotheses have proposed an Andean area (somewhere from upland Venezuela to northern Argentina) or a lowland south central Chilean area. Potato landraces from these two areas can be distinguished, although sometimes with difficulty, by (1) cytoplasmic sterility factors, (2) morphological traits, (3) daylength adaptation, (4) microsatellite markers, and (5) co-evolved chloroplast (cp) and mitochondria (mt) DNA. The Chilean introduction hypothesis originally was proposed because of similarities among Chilean landraces and modern European cultivars with respect to traits 2 and 3. Alternatively, the Andean introduction hypothesis suggests that (1) traits 2 and 3 of European potato evolved rapidly, in parallel, from Andean landraces to a Chilean type through selection following import to Europe, and (2) the worldwide late blight epidemics beginning in 1845 in the United Kingdom displaced most existing European cultivars and the potato was subsequently improved by importations of Chilean landraces. We reassess these two competing hypotheses with nuclear microsatellite and cpDNA analyses of (1) 32 Indian cultivars, some of which are thought to preserve putatively remnant populations of Andean landraces, (2) 12 Andean landraces, and (3) five Chilean landraces. Our microsatellite results cluster all Indian cultivars, including putatively remnant Andean landrace populations, with the Chilean landraces, and none with the old Andigenum landraces. Some of these Indian landraces, however, lack the cpDNA typical of Chilean landraces and advanced cultivars, indicating they likely are hybrids of Andean landraces with Chilean clones or more advanced cultivars. These results lead us to reexamine the hypothesis that early introductions of potato to Europe were solely from the Andes. 相似文献
63.
Blamey CJ Ceccarelli C Naik UP Bahnson BJ 《Protein science : a publication of the Protein Society》2005,14(5):1214-1221
Calcium- and integrin-binding protein 1 (CIB1) is involved in the process of platelet aggregation by binding the cytoplasmic tail of the alpha(IIb) subunit of the platelet-specific integrin alpha(Iib)beta(3). Although poorly understood, it is widely believed that CIB1 acts as a global signaling regulator because it is expressed in many tissues that do not express integrin alpha(Iib)beta(3). We report the structure of human CIB1 to a resolution of 2.3 A, crystallized as a dimer. The dimer interface includes an extensive hydrophobic patch in a crystal form with 80% solvent content. Although the dimer form of CIB1 may not be physiologically relevant, this intersub-unit surface is likely to be linked to alpha(IIb) binding and to the binding of other signaling partner proteins. The C-terminal domain of CIB1 is structurally similar to other EF-hand proteins such as calmodulin and calcineurin B. Despite structural homology to the C-terminal domain, the N-terminal domain of CIB1 lacks calcium-binding sites. The structure of CIB1 revealed a complex with a molecule of glutathione in the reduced state bond to the N-terminal domain of one of the two subunits poised to interact with the free thiol of C35. Glutathione bound in this fashion suggests CIB1 may be redox regulated. Next to the bound GSH, the orientation of residues C35, H31, and S48 is suggestive of a cysteine-type protein phosphatase active site. The potential enzymatic activity of CIB1 is discussed and suggests a mechanism by which it regulates a wide variety of proteins in cells in addition to platelets. 相似文献
64.
Development of murine plasmacytoid dendritic cell subsets 总被引:3,自引:0,他引:3
65.
Morus spp., commonly known as mulberry, is significantly associated with human civilization and spread of silk-culture from Asia to Europe, Africa and Latin America. One of its species, Morus laevigata, traditionally well known for its timber value, forage use and silkworm's feed, is widely distributed in India extending from Himalayan foothill to Andaman islands. The variability occurring for 12 morpho-biochemical parameters and RAPD profiles, generated with 13 selected RAPD primers, for M. laevigata accessions from six different zones were investigated. Analyses revealed high degree of genotypic similarity of collection from Himalayan foothill (West Bengal) with those from Andaman Islands. Specific accessions from central India and south India also revealed genotypic similarities with specific accessions from north-east India. These observations are discussed in the context of clonal propagation of mulberry and evolutionary perspective of dispersal of this species, through human activities 相似文献
66.
BACKGROUND: Small cell anaplastic hepatoblastoma (HB) is the least common subtype of HB. There are few articles in the literature describing the cytologic characteristics of this rare subtype. CASE: A 5-year-old girl present with a progressively enlarging abdominal mass. Ultrasound examination revealed the mass to be arising within the right lobe of the liver. Fine needle aspiration (FNA) of the mass revealed primitive cells with a high nuclear/cytoplasmic ratio and hyperchromatic, ovoid nuclei in poorly cohesive clusters as well as dispersed singly. These cells closely resembled those of small round cell tumors of childhood. CONCLUSION: The cytologic differential diagnosis of undifferentiated HB must include small round cell tumors of childhood. With knowledge of the typical cytomorphologic appearance of HB in association with clinical and radiologic information, one can offer a reliable preoperative diagnosis on FNA. 相似文献
67.
Xiang L Naik JS Hodnett BL Hester RL 《American journal of physiology. Regulatory, integrative and comparative physiology》2006,290(1):R134-R138
These studies tested the hypothesis that in obese Zucker rats (OZRs), a model of metabolic syndrome, the impaired functional vasodilation is due to increased thromboxane receptor (TP)-mediated vasoconstriction and/or decreased prostacyclin-induced vasodilation. Spinotrapezius arcade arterioles from 12-wk-old lean (LZR) and OZR were chosen for microcirculatory observation. Arteriolar diameter (5 LZR and 6 OZR) was measured after 2 min of muscle stimulation in the absence or presence of 1 microM SQ-29548 (TP antagonist). Additionally, arteriolar diameter (6 for each group) was measured after application of iloprost (prostacyclin analog; 0.28, 2.8, and 28 microM), arachidonic acid (10 microM), and sodium nitroprusside (0.1, 1, and 10 microM) in the absence or presence of 1 microM SQ-29548. A 10 microM concentration of adenosine was used to induce a maximal dilation. Basal diameters were not different between LZRs and OZRs. Functional hyperemia and arachidonic acid-mediated vasodilations were significantly attenuated in OZR compared with LZR, and treatment with 1 microM SQ-29548 significantly enhanced the dilations in OZRs, although it had no effect in LZRs. Vasodilatory responses to iloprost and sodium nitroprusside (1 and 10 microM) were significantly reduced in OZR. Adenosine-mediated vasodilation was not different between groups. These results suggest that the impaired functional dilation in the OZR is due to an increased TP-mediated vasoconstriction and a decreased PGI2-induced vasodilation. 相似文献
68.
The understanding of erythrocyte deformation under conditions of high shear stress and short exposure time is central to the study of hemorheology and hemolysis within prosthetic blood contacting devices. A combined computational and experimental microscopic study was conducted to investigate the erythrocyte deformation and its relation to transient stress fields. A microfluidic channel system with small channels fabricated using polydimethylsiloxane on the order of 100 mum was designed to generate transient stress fields through which the erythrocytes were forced to flow. The shear stress fields were analyzed by three-dimensional computational fluid dynamics. Microscopic images of deforming erythrocytes were experimentally recorded to obtain the changes in cell morphology over a wide range of fluid dynamic stresses. The erythrocyte elongation index (EI) increased from 0 to 0.54 with increasing shear stress up to 123 Pa. In this shear stress range, erythrocytes behaved like fluid droplets, and deformed and flowed following the surrounding fluid. Cells exposed to shear stress beyond 123 Pa (up to 5170 Pa) did not exhibit additional elongation beyond EI=0.54. Two-stage deformation of erythrocytes in response to shear stress was observed: an initial linear elongation with increasing shear stress and a plateau beyond a critical shear stress. 相似文献
69.
Jasmonic acid induced changes in protein pattern, antioxidative enzyme activities and peroxidase isozymes in peanut seedlings 总被引:1,自引:0,他引:1
G. J. Kumari A. M. Reddy S. T. Naik S. G. Kumar J. Prasanthi G. Sriranganayakulu P. C. Reddy Chinta Sudhakar 《Biologia Plantarum》2006,50(2):219-226
Protein pattern, ammonia content, glutamine synthetase activity, lipid peroxidation, superoxide dismutase, catalase, peroxidase
and peroxidase isoforms were studied in the leaves and roots of 7-d-old peanut (Arachis hypogaea L. cv. JL-24) seedlings treated by 25, 100 and 250 μM jasmonic acid (JA). SDS-PAGE protein profile of leaves and roots after
JA application showed a significant increase in 18, 21, 30, 45, 47 and 97.4 kDa proteins and significant decrease in 22 and
36 kDa proteins. Pathogenesis related PR-18 was specific in leaves at 250 μM JA and PR-21 have cross reacted differently with
21 and 30 kDa proteins in leaves and roots treated by all JA concentrations. Further, the immunoblot analysis with glutamine
synthetase, GS-45 antibodies revealed a specific cross reaction with 45 and 47 kDa proteins of both control and JA treated
leaves, however, higher at 100 and 250 μM JA treated leaves than control ones. Further, the malondialdehyde (MDA) content
significantly increased in leaves and roots treated with JA, indicated membrane damage with JA treatments that led to the
generation of peroxidation products. The peroxidase isozymic pattern showed two specific isoforms. Besides, the activities
of SOD and catalase were significantly elevated in JA treated leaves. 相似文献
70.
Aravindan RG Fomin VP Naik UP Modelski MJ Naik MU Galileo DS Duncan RL Martin-Deleon PA 《Journal of cellular physiology》2012,227(8):3138-3150
Deletion of the highly conserved gene for the major Ca2+ efflux pump, Plasma membrane calcium/calmodulin‐dependent ATPase 4b (Pmca4b), in the mouse leads to loss of progressive and hyperactivated sperm motility and infertility. Here we first demonstrate that compared to wild‐type (WT), Junctional adhesion molecule‐A (Jam‐A) null sperm, previously shown to have motility defects and an abnormal mitochondrial phenotype reminiscent of that seen in Pmca4b nulls, exhibit reduced (P < 0.001) ATP levels, significantly (P < 0.001) greater cytosolic Ca2+ concentration ([Ca2+]c) and ~10‐fold higher mitochondrial sequestration, indicating Ca2+ overload. Investigating the mechanism involved, we used co‐immunoprecipitation studies to show that CASK (Ca2+/calmodulin‐dependent serine kinase), identified for the first time on the sperm flagellum where it co‐localizes with both PMCA4b and JAM‐A on the proximal principal piece, acts as a common interacting partner of both. Importantly, CASK binds alternatively and non‐synergistically with each of these molecules via its single PDZ (PDS‐95/Dlg/ZO‐1) domain to either inhibit or promote efflux. In the absence of CASK–JAM‐A interaction in Jam‐A null sperm, CASK–PMCA4b interaction is increased, resulting in inhibition of PMCA4b's enzymatic activity, consequent Ca2+ accumulation, and a ~6‐fold over‐expression of constitutively ATP‐utilizing CASK, compared to WT. Thus, CASK negatively regulates PMCA4b by directly binding to it and JAM‐A positively regulates it indirectly through CASK. The decreased motility is likely due to the collateral net deficit in ATP observed in nulls. Our data indicate that Ca2+ homeostasis in sperm is maintained by the relative ratios of CASK–PMCA4b and CASK–JAM‐A interactions. J. Cell. Physiol. 227: 3138–3150, 2012. © 2011 Wiley Periodicals, Inc. 相似文献