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101.
Applied Intelligence - The17 Sustainable Development Goals (SDGs) established by the United Nations Agenda 2030 constitute a global blueprint agenda and instrument for peace and prosperity...  相似文献   
102.
On the basis of results of a probe trial in 2 different experiments, K. Cheng (2005) has proposed a common mechanism for orientation in fish trained in both a maplike or relational procedure and a directly cued procedure. However, K. Cheng's model is inconsistent with previous results of goldfish (Carassius auratus) trained in these 2 tasks. Given that K. Cheng's proposal assumes that fish choose the goal by using a matching strategy in which they try to match as many properties as possible, including geometric and featural properties, future research is necessary to clarify what properties of the environmental space are codified and used for navigation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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104.
Several actin-binding proteins participate in the morphological changes that occur during amoeboid movement. The gene encoding one of these proteins, the gelation factor ABP-120, was identified and characterized from trophozoites of Entamoeba histolytica. The sequence contains 2574 nucleotides, with an open reading frame of 858 amino acids, giving a protein of 93 kDa belonging to the spectrin family. The N-terminal domain of ABP-120 from E. histolytica revealed a consensus site for actin binding homologous to the actin-binding sites of ABP-120 of Dictyostelium discoideum, alpha-actinin and spectrin. Analysis of the central domain revealed the presence of four repeats of a 73-amino-acid motif constituting 31% of the protein. In addition, a stretch of 105 amino acids was highly divergent when compared with the C-terminal domain of D. discoideum ABP-120. This sequence showed short motifs that are homologous to microtubule-binding domains. We found that ABP-120 from E. histolytica binds to F-actin. In addition, upon motility of the parasite, this protein localized in the pseudopod and the uroid region, implying a role for ABP-120 in movement and capping of surface receptors in E. histolytica.  相似文献   
105.
Tryptophan hydroxylase (TPH) is the first enzyme in both serotonin and melatonin biosynthesis in neuroendocrine cells of the pineal gland. The lack of immortalized neuroendocrine pineal cell lines has been a major obstacle to the study of the tissue-specific and circadian regulation of TPH gene expression in the pineal gland. Previously, we demonstrated that a 6.1 kb 5' upstream region of the mouse TPH gene directs the restricted expression of a lacZ reporter gene to the pineal gland and the raphe nuclei of transgenic mice. Therefore, to develop TPH-expressing pineal cell lines we first established transgenic mice carrying a construct consisting of 6.1 kb of 5' flanking region fused to the SV40 T-antigen. These animals developed highly invasive pineal tumors and died at 12-15 weeks of age. The pineal tumors obtained from the transgenic mice were utilized to establish the immortalized pinealocyte-derived cell lines. These cells express two marker enzymes, TPH and serotonin N-acetyltransferase (NAT). In pineal gland TPH and NAT expressions have been known to be regulated during circadian cycle. The two established cell lines therefore promise to be a valuable in vitro model system for the study of the rhythmic nature of the pineal function at molecular level in mammal.  相似文献   
106.
We examined associations between lifestyle factors and subsequent risk of prostate cancer in a population-based case-control study. Information on smoking and alcohol habits, socioeconomic factors, marital status, family history, and sexual habits were obtained from a questionnaire and a face-to-face interview with 256 (74.6%) eligible patients and 252 (76.6%) selected controls, frequency matched by age and screened for prostate cancer with negative findings. Unconditional logistic regression was used to estimate the odds ratios (ORs). Risk was elevated among current smokers of cigarettes (OR, 1.8) and current users of hard liquor (OR, 1.4); however, the lack of dose-response trend for both of these exposures argues against a causal association. We found tentative evidence that early first intercourse, a larger number of sexual partners, and other indices of high sexual activity are associated with increased risk. Similarly, adult height, an indicator of nutrition during childhood and adolescence, was weakly positively associated with risk, although larger studies are needed to establish this link. Unmarried men had a lower risk than married men (OR, 0.3), and socioeconomic status did not appear to be strongly associated with prostate cancer. Men with a father who had prostate cancer had a more than 2-fold increased risk of prostate cancer, whereas those with a brother affected had about a 5-folk risk.  相似文献   
107.
Growth hormone (GH) signaling requires activation of the GH receptor (GHR)-associated tyrosine kinase, JAK2. JAK2 activation by GH is believed to facilitate initiation of various pathways including the Ras, mitogen-activated protein kinase, STAT, insulin receptor substrate (IRS), and phosphatidylinositol 3-kinase systems. In the present study, we explore the biochemical and functional involvement of the Src homology 2 (SH2)-containing protein-tyrosine phosphatase, SHP-2, in GH signaling. GH stimulation of murine NIH 3T3-F442A fibroblasts, cells that homologously express GHRs, resulted in tyrosine phosphorylation of SHP-2. As assessed specifically by anti-SHP-2 coimmunoprecipitation and by affinity precipitation with a glutathione S-transferase fusion protein incorporating the SH2 domains of SHP-2, GH induced formation of a complex of tyrosine phosphoproteins including SHP-2, GHR, JAK2, and a glycoprotein with properties consistent with being a SIRP-alpha-like molecule. A reciprocal binding assay using IM-9 cells as a source of SHP-1 and SHP-2 revealed specific association of SHP-2 (but not SHP-1) with a glutathione S-transferase fusion incorporating GHR cytoplasmic domain residues 485-620, but only if the fusion was first rendered tyrosine-phosphorylated. GH-dependent tyrosine phosphorylation of SHP-2 was also observed in murine 32D cells (which lack IRS-1 and -2) stably transfected with the GHR. Further, GH-dependent anti-SHP-2 coimmunoprecipitation of the Grb2 adapter protein was detected in both 3T3-F442A and 32D-rGHR cells, indicating that biochemical involvement of SHP-2 in GH signaling may not require IRS-1 or -2. Finally, GH-induced transactivation of a c-Fos enhancer-driven luciferase reporter in GHR- and JAK2-transfected COS-7 cells was significantly reduced when a catalytically inactive SHP-2 mutant (but not wild-type SHP-2) was coexpressed; in contrast, expression of a catalytically inactive SHP-1 mutant allowed modestly enhanced GH-induced transactivation of the reporter in comparison with that found with expression of wild-type SHP-1. Collectively, these biochemical and functional data imply a positive role for SHP-2 in GH signaling.  相似文献   
108.
109.
The bovine papillomavirus E5 protein is a small, homodimeric transmembrane protein that forms a stable complex with the cellular platelet-derived growth factor (PDGF) beta receptor through transmembrane and juxtamembrane interactions, resulting in receptor activation and cell transformation. Glutamine 17 in the transmembrane domain of the 44-amino-acid E5 protein is critical for complex formation and receptor activation, and we previously proposed that glutamine 17 forms a hydrogen bond with threonine 513 of the PDGF beta receptor. We have constructed and analyzed mutant E5 proteins containing all possible amino acids at position 17 and examined the ability of these proteins to transform C127 fibroblasts, which express endogenous PDGF beta receptor. Although several position 17 mutants were able to transform cells, mutants containing amino acids with side groups that were unable to participate in hydrogen bonding interactions did not form a stable complex with the PDGF beta receptor or transform cells, in agreement with the proposed interaction between position 17 of the E5 protein and threonine 513 of the receptor. The nature of the residue at position 17 also affected the ability of the E5 proteins to dimerize. Overall, there was an excellent correlation between the ability of the various E5 mutant proteins to bind the PDGF beta receptor, lead to receptor tyrosine phosphorylation, and transform cells. Similar results were obtained in Ba/F3 hematopoietic cells expressing exogenous PDGF beta receptor. In addition, treatment of E5-transformed cells with a specific inhibitor of the PDGF receptor tyrosine kinase reversed the transformed phenotype. These results confirm the central importance of the PDGF beta receptor in mediating E5 transformation and highlight the critical role of the residue at position 17 of the E5 protein in the productive interaction with the PDGF beta receptor. On the basis of molecular modeling analysis and the known chemical properties of the amino acids, we suggest a structural basis for the role of the residue at position 17 in E5 dimerization and in complex formation between the E5 protein and the PDGF beta receptor.  相似文献   
110.
The phosphate sensor   总被引:1,自引:0,他引:1  
The field of phosphate sensors is reviewed. Sensors in the form of potentiometric ion-selective electrodes, amperometric and potentiometric enzyme electrodes, amperometric plant-tissue electrodes and other devices in the form of integrated probes used for determining orthophosphate concentrations in aqueous solutions, are described. Information provided includes conditions like pH and temperature at which the device is operated, as well as experimental results in the form of linear ranges, detection limits and interfering substances. The time period covered ranges from 1986 up to mid-1997. Earlier work is included in some cases.  相似文献   
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