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81.
Plant distribution and dispersal mechanisms at the Hassayampa River Preserve, Arizona, USA 总被引:1,自引:0,他引:1
Taly Dawn Drezner Patricia L. Fall Juliet C. Stromberg† 《Global Ecology and Biogeography》2001,10(2):205-217
This study focuses on the relationships between plant dispersal syndromes and plant distributions at the community scale. Species composition and cover are reported from 29 10 × 20-m vegetation plots along five topographic cross-sections in the riparian zone of the Hassayampa River Preserve, Arizona. We find that spatial patterns of dispersal guilds vary within the flood plain of this semiarid region river. Our main results are: (1) wind-dispersed species are fairly evenly distributed at all elevations and distances from the river, whereas cover of animal-dispersed species increases with elevation above, and at greater distances from, the river; (2) wind-dispersed species are proportionally more abundant in the pioneer Populus–Salix community, whereas plants in the late-seral Prosopis community are predominantly animal-dispersed; (3) most of the species classified as obligate-wetland and facultative-wetland are wind-dispersed, whereas facultative-upland and obligate-upland species are mostly animal-dispersed; and (4) there are significantly fewer wind-dispersed species in areas of high total vegetation cover. These results may reflect successional patterns resulting from periodic flooding. Low areas close to the river flood more frequently and with greater intensity than areas farther from the river. Many pioneer species that establish in disturbed areas are wind-dispersed. Over successional time, pioneer species cede to more drought tolerant species that are predominantly animal-dispersed. 相似文献
82.
83.
Leo R. Chavez Juliet M. McMullin Shiraz I. Mishra F. Allan Hubbell 《American anthropologist》2001,103(4):1114-1129
In this article we examine the influence of cultural beliefs on behavior or, more specifically, beliefs about cervical cancer risk factors and the use of Pap exams. Individual Latinas' (Hispanic women) holding of beliefs similar to Latinas' generally (cultural consonance) did not significantly influence their use of Pap exams. Rather, structural factors such as medical insurance, age, marital status, education, and language acculturation explained Latinas' use of this medical service. However, when Latinas held beliefs similar to those of Anglo women, then they were significantly more likely to have had a Pap exam within the past two years. Latinas whose beliefs were closer to those of physicians were significantly less likely to have had the exam recently. Arriving at these findings involved both ethnographic interviews and survey research. That these beliefs proved to be significant influences on behavior suggests not only the important ways that beliefs matter but that ethnographic methods for examining those beliefs also matter. [ Latinas and cervical cancer, Pap exams, culture and behavior, ethnography and survey research ] 相似文献
84.
Buffie J. Clodfelder Juliet Emamaullee Dion D. Hepburn Nicole E. Chakov Heather S. Nettles John B. Vincent 《Journal of biological inorganic chemistry》2001,6(5-6):608-617
The chromium-binding oligopeptide chromodulin (also known as low-molecular-weight chromium-binding substance) has been shown to activate the tyrosine kinase activity of the insulin receptor in response to insulin and has been proposed to be part of a novel autoamplification mechanism for insulin signaling. The model requires that Cr3+ be moved from the blood to insulin-sensitive tissues in response to insulin and subsequently be lost in the urine as chromodulin; however, the model has not been tested by in vivo studies. In vivo studies with rats have shown that the iron transport protein transferrin serves as the major chromic ion transport agent and that this transport is stimulated by insulin. The ion is transported to a variety of tissues, while liver and kidneys are the major target. In hepatocytes, chromodulin occurs in appreciable levels in the cytosol and in the nucleus. Apochromodulin levels appear to be maintained under homeostatic control, although the only detectable form of urinary chromium is probably chromodulin. Increases in urinary chromium loss in response to insulin are reflected by increases in chromodulin, establishing a direct link between carbohydrate metabolism and the oligopeptide. 相似文献
85.
Dr. Juliet Morgan Louis Cohen 《In vitro cellular & developmental biology. Plant》1974,10(3-4):188-195
Summary This report describes in detail a method of enzymatic separation of adult mammalian muscle using papain. The procedure has
proved valuable in the preparation of suspensions of muscle cell pieces from normal human skeletal muscle obtained from patients
of all ages, from 3 months to 79 years. Muscle cultures have been successfully growth from biopsy material from boys with
Duchenne’s muscular dystrophy and from their mothers. The procedure was initially established with adult canine skeletal muscle
and has also been used for monkey muscle.
Small pieces of skeletal muscle are chopped in a solution of 0.05% papain and 0.01% cysteine hydrochloride in Ca2+-and Mg2+-free balanced salt solution and transferred in the papain solution to a flask, in which they are incubated at 37°C for 10
min with occasional agitation. The resulting cell suspension is collected and the remaining pieces are treated with further
portions of fresh papain until only connective tissue remains. The cell pellets obtained by centrifugation are resuspended
in Eagle’s minimum essential medium (supplemented with 20% fetal calf serum) and transferred to culture chambers. The muscle
can be observed at all times, during the separation procedure and subsequently in culture. The events occurring during skeletal
muscle regeneration can be followed. Using the same papain preparation, myoblasts and myotubes may be subcultured and collected
for indefinite frozen storage in dimethylsulfoxide.
This work was supported by a grant-in-aid from the American Heart Association with funds contributed in part by the Chicago
Heart Association, the Pharmaceutical Manufactures Association, and National Institutes of Health Research Grant NS 10385
from the Institute of Neurological Diseases and Stroke. 相似文献
86.
Derek Kennedy Juliet French Estelle Guitard Kelin Ru Bruno Tocque John Mattick 《Journal of cellular biochemistry》2002,84(1):173-187
The G3BP (ras‐GTPase‐Activating Protein SH3‐Domain‐Binding Protein) family of proteins has been implicated in both signal transduction and RNA‐metabolism. We have previously identified human G3BP‐1, G3BP‐2, and mouse G3BP‐2. Here, we report the cloning of mouse G3BP‐1, the discovery of two alternatively spliced isoforms of mouse, and human G3BP‐2 (G3BP‐2a and G3BP‐2b), and the chromosomal localisation of human G3BP‐1 and G3BP‐2, which map to 5q14.2‐5q33.3 and 4q12‐4q24 respectively. We mapped the rasGAP120 interactive region of the G3BP‐2 isoforms and show that both G3BP‐2a and G3BP‐2b use an N‐terminal NTF2‐like domain for rasGAP120 binding rather than several available proline‐rich (PxxP) motifs found in members of the G3BPs. Furthermore, we have characterized the protein expression of both G3BP‐1 and G3BP‐2a/b in adult mouse tissues, and show them to be both tissue and isoform specific. J. Cell. Biochem. 84: 173–187, 2002. © 2001 Wiley‐Liss, Inc. 相似文献
87.
Transcriptomics reveal transgenerational effects in purple sea urchin embryos: Adult acclimation to upwelling conditions alters the response of their progeny to differential pCO2 levels
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Juliet M. Wong Kevin M. Johnson Morgan W. Kelly Gretchen E. Hofmann 《Molecular ecology》2018,27(5):1120-1137
88.
Helen Louise May-Simera Qin Wan Balendu Shekhar Jha Juliet Hartford Vladimir Khristov Roba Dejene Justin Chang Sarita Patnaik Quanlong Lu Poulomi Banerjee Jason Silver Christine Insinna-Kettenhofen Dishita Patel Mostafa Lotfi May Malicdan Nathan Hotaling Arvydas Maminishkis Rupa Sridharan Kapil Bharti 《Cell reports》2018,22(1):189-205
89.
David M Hunt Jill A Cowing Susan E Wilkie Juliet W L Parry Subathra Poopalasundaram James K Bowmaker 《Photochemical & photobiological sciences》2004,3(8):713-720
Of the four classes of vertebrate cone visual pigments, the shortwave-sensitive SWS1 class shows the shortest lambda(max) values with peaks in different species in either the violet (390-435 nm) or ultraviolet (around 365 nm) regions of the spectrum. Phylogenetic evidence indicates that the ancestral pigment was probably UV-sensitive (UVS) and that the shifts between violet and UV have occurred many times during evolution. This is supported by the different mechanisms for these shifts in different species. All visual pigments possess a chromophore linked via a Schiff base to a Lys residue in opsin protein. In violet-sensitive (VS) pigments, the Schiff base is protonated whereas in UVS pigments, it is almost certainly unprotonated. The generation of VS from ancestral UVS pigments most likely involved amino acid substitutions in the opsin protein that serve to stabilise protonation. The key residues in the opsin protein for this are at sites 86 and 90 that are adjacent to the Schiff base and the counterion at Glu113. In this review, the different molecular mechanisms for the UV or violet shifts are presented and discussed in the context of the structural model of bovine rhodopsin. 相似文献
90.
Mariya T Sweetwyne Rolf A Brekken Gail Workman Amy D Bradshaw Juliet Carbon Anthony W Siadak Carrie Murri E Helene Sage 《The journal of histochemistry and cytochemistry》2004,52(6):723-733
SPARC (osteonectin, BM-40) is a matricellular glycoprotein that is expressed in many embryogenic and adult tissues undergoing remodeling or repair. SPARC modulates cellular interaction with the extracellular matrix (ECM), inhibits cell adhesion and proliferation, and regulates growth factor activity. To explore further the function and activity of this protein in tissue homeostasis, we have developed several monoclonal antibodies (MAbs) that recognize distinct epitopes on SPARC. The MAbs bind to SPARC with high affinity and identify SPARC by ELISA, Western blotting, immunoprecipitation, immunocytochemistry, and/or immunohistochemistry. The MAbs were also characterized in functional assays for potential alteration of SPARC activity. SPARC binds to collagen I and laminin-1 through an epitope defined by MAb 293; this epitope is not involved in the binding of SPARC to collagen III. The other MAbs did not interfere with the binding of SPARC to collagen I or III or laminin-1. Inhibition of the anti-adhesive effect of SPARC on endothelial cells by MAb 236 was also observed. Functional analysis of SPARC in the presence of these novel MAbs now confirms that the activities ascribed to this matricellular protein can be assigned to discrete subdomains. 相似文献