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1.
Ann-ping Tsou Alan Kosaka Chinh Bach Patti Zuppan Calvin Yee Leonard Tom Robert Alvarez Scott Ramsey Douglas W. Bonhaus Eric Stefanich Lyn Jakeman Richard M. Eglen Hardy W. Chan 《Journal of neurochemistry》1994,63(2):456-464
Abstract: In a number of different cell types, phosphorylation of a 63-kDa protein has been shown to increase rapidly in response to stimuli that lead to an increase in intracellular calcium. Here, a stimulus-sensitive protein at this molecular weight is identified in PC12 cells and rat cortical synaptosomes as phosphoglucomutase. In addition, the added phosphate is shown to be in an oligosaccharide terminating in phosphodiester-linked glucose. In synaptosomes, incorporated radioactivity, following incubation with [14 C]glucose or the [β-35 S]phosphorothioate analogue of UDP-glucose, was found to increase within 5 s of stimulation and return to baseline within 25 s. Despite the many pathways utilizing glucose, this was the only detectable protein glycosylation observed in synaptosomes. These results indicate that cytoplasmic glycosylation is reversible and rapidly regulated, and suggest that phosphoglucomutase undergoes an alteration in function and/or topography in response to increases in intracellular calcium. 相似文献
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Martin RS Reynen PH Calixto JJ Reyes CL Chang TK Dietrich PS Bonhaus DW MacLennan SJ 《Journal of biomolecular screening》2002,7(3):281-289
The pharmacology of G protein-coupled receptors is widely accepted to depend on the G protein subunit to which the agonist-stimulated receptor couples. In order to investigate whether CB(1) agonist-mediated signal transduction via an engineered G(alpha 16) system is different than that of the G(i/o) coupling normally preferred by the CB(1) receptor, we transfected the human recombinant CB(1) receptor (hCB(1)) or a fusion protein comprising the hCB(1) receptor and G(alpha 16) (hCB(1)-G(alpha 16)) into HEK293 cells. From competition binding studies, the rank order of ligand affinities at the hCB(1)-G(alpha 16) fusion protein was found to be similar to that for hCB(1): HU 210 > CP 55,940 > or = SR 141716A > WIN 55212-2 > anandamide > JWH 015. Agonists increased [(35)S]GTP gamma S binding or inhibited forskolin-stimulated cAMP, presumably by coupling to G(i/o), in cells expressing hCB(1) but not hCB(1)-G(alpha 16). However, an analogous rank order of potencies was observed for these agonists in their ability to evoke increases in intracellular calcium concentration in cells expressing hCB(1)-G(alpha 16) but not hCB(1). These data demonstrate that ligand affinities for the hCB(1) receptor are not affected by fusion to the G(alpha 16) subunit. Furthermore, there is essentially no difference in the function of the hCB(1) receptor when coupled to G(i/o) or G (alpha 16). 相似文献
4.
Current status of antisense DNA methods in behavioral studies 总被引:4,自引:0,他引:4
The antisense DNA method has been used successfully to block the expression
of specific genes in vivo in neuronal systems. An increasing number of
studies in the last few years have shown that antisense DNA administered
directly into the brain can modify various kinds of behaviors. These
findings strongly suggest that the antisense DNA method can be used as a
powerful tool to study causal relationships between molecular processes in
the brain and behavior. In this article we review the current status of the
antisense method in behavioral studies and discuss its potentials and
problems by focusing on the following four aspects; (i) optimal application
paradigms of antisense DNA methods in behavioral studies; (ii) efficiencies
of different administration methods of antisense DNA used in behavioral
studies; (iii) determination of specificity of behavioral effects of
antisense DNA; and (iv) discrepancies between antisense DNA effects on
behaviors and those on protein levels of the targeted gene.
相似文献
5.
Paul DW Kirk Aviva Witkover Alan Courtney Alexandra M Lewin Robin Wait Michael PH Stumpf Sylvia Richardson Graham P Taylor Charles RM Bangham 《Retrovirology》2011,8(1):1-9
Background
A new subgroup of HIV-1, designated Group P, was recently detected in two unrelated patients of Cameroonian origin. HIV-1 Group P phylogenetically clusters with SIVgor suggesting that it is the result of a cross-species transmission from gorillas. Until today, HIV-1 Group P has only been detected in two patients, and its degree of adaptation to the human host is largely unknown. Previous data have shown that pandemic HIV-1 Group M, but not non-pandemic Group O or rare Group N viruses, efficiently antagonize the human orthologue of the restriction factor tetherin (BST-2, HM1.24, CD317) suggesting that primate lentiviruses may have to gain anti-tetherin activity for efficient spread in the human population. Thus far, three SIV/HIV gene products (vpu, nef and env) are known to have the potential to counteract primate tetherin proteins, often in a species-specific manner. Here, we examined how long Group P may have been circulating in humans and determined its capability to antagonize human tetherin as an indicator of adaptation to humans.Results
Our data suggest that HIV-1 Group P entered the human population between 1845 and 1989. Vpu, Env and Nef proteins from both Group P viruses failed to counteract human or gorilla tetherin to promote efficient release of HIV-1 virions, although both Group P Nef proteins moderately downmodulated gorilla tetherin from the cell surface. Notably, Vpu, Env and Nef alleles from the two HIV-1 P strains were all able to reduce CD4 cell surface expression.Conclusions
Our analyses of the two reported HIV-1 Group P viruses suggest that zoonosis occurred in the last 170 years and further support that pandemic HIV-1 Group M strains are better adapted to humans than non-pandemic or rare Group O, N and P viruses. The inability to antagonize human tetherin may potentially explain the limited spread of HIV-1 Group P in the human population. 相似文献6.
7.
L-Lactate dehydrogenase (L-LDH, E.C. 1.1.1.27) is encoded by two or three
loci in all vertebrates examined, with the exception of lampreys, which
have a single LDH locus. Biochemical characterizations of LDH proteins have
suggested that a gene duplication early in vertebrate evolution gave rise
to Ldh-A and Ldh-B and that an additional locus, Ldh-C arose in a number of
lineages more recently. Although some phylogenetic studies of LDH protein
sequences have supported this pattern of gene duplication, others have
contradicted it. In particular, a number of studies have suggested that
Ldh-C represents the earliest divergence among vertebrate LDHs and that it
may have diverged from the other loci well before the origin of
vertebrates. Such hypotheses make explicit statements about the
relationship of vertebrate and invertebrate LDHs, but to date, no closely
related invertebrate LDH sequences have been available for comparison. We
have attempted to provide further data on the timing of gene duplications
leading to multiple vertebrate LDHs by determining the cDNA sequence of the
LDH of the tunicate Styela plicata. Phylogenetic analyses of this and other
LDH sequences provide strong support for the duplications giving rise to
multiple vertebrate LDHs having occurred after vertebrates diverged from
tunicates. The timing of these LDH duplications is consistent with data
from a number of other gene families suggesting widespread gene duplication
near the origin of vertebrates. With respect to the relationships among
vertebrate LDHs, our data are not consistent with previous claims that
Ldh-C represented the earliest divergence. However, the precise
relationships among some of the main lineages of vertebrate LDHs were not
resolved in our analyses.
相似文献
8.
Douglas W. Bonhaus Eric Stefanich Dana N. Loury Sherry A. O. Hsu Richard M. Eglen Erik H. F. Wong 《Journal of neurochemistry》1995,65(1):104-110
Abstract: Cooperation in the action of agonists suggests that there are multiple binding sites on 5-hydroxytryptamine3 (5-HT3 ) receptors. The purpose of this study was to characterize these binding sites and their interactions on both native and cloned 5-HT3 receptors. The affinities of competitive 5-HT3 receptor antagonists were similar regardless of whether the receptors were labeled with [3 H]RS-42358, [3 H]granisetron, or 1-( m -[3 H]chlorophenyl)biguanide ([3 H]mCPG). By contrast, the affinities of the agonists 5-HT, mCPG, and phenylbiguanide were approximately 10-fold higher when the receptors were labeled with [3 H]mCPG. The dissociation of [3 H]mCPG, [3 H]RS-42358, and [3 H]RS-25259, but not [3 H]granisetron, from both cloned and native 5-HT3 receptors was markedly slower in the presence of 5-HT or 2-methyl-5-HT than in the presence of antagonists such as RS-42358. This suggests that the binding of these agonists to unoccupied sites on the receptor can increase the receptor's affinity for prebound ligands and thereby slow their dissociation. These data support previous indications of positive cooperation among multiple binding sites on both native and cloned 5-HT3 receptors, and they extend this idea by demonstrating that agonists can modify the interaction of some, but not all, antagonists with the receptor. 相似文献
9.
Lois DW Arnold 《International breastfeeding journal》2006,1(1):1-8
Background
The past ten years have witnessed a rising trend in the prevalence and duration of breastfeeding in Italy, but breastfeeding rates increase in an unequal way; they are higher in the North of Italy than in the South. The purpose of this study was to describe the experiences, expectations and beliefs of a sample of mothers, and to identify differences, if any, between the North and the South of Italy.Methods
The study was conducted in two regions of Italy, Friuli Venezia Giulia in the Northeast and Basilicata in the South. Two hundred and seventy-nine mothers of infants and children 6 to 23 months of age were interviewed using an 85-item questionnaire including closed and open questions on infant feeding experiences and beliefs, sources of information and support, reasons for intended and actual choices and practices, and some demographic and social variables. Face-to-face interviews were conducted between May 2001 and September 2002. Quantitative and qualitative methods were used for data analysis.Results
The distribution of the mothers by age, education, employment and parity did not differ from that of the general population of the two regions. The reported rates of initiation and duration of breastfeeding were also similar: 95% started breastfeeding, exclusive breastfeeding was 32% at three and 9% at six months, with 64% and 35% of any breastfeeding, respectively. Some differences were reported in the rates of full breastfeeding, reflecting different ages of introduction of non-nutritive fluids. These, as well as nutritive fluids – including infant formula – and complementary foods, were introduced far too early. Advice on infant feeding was generally provided by health professionals and often was not based on up-to-date recommendations. Mothers were generally aware of the advantages of breastfeeding, but at the same time reported problems that they were not able to solve alone or through social and health system support. Most mothers would welcome the support of a peer counsellor. More mothers in Basilicata than in Friuli Venezia Giulia reported difficulties with breastfeeding related to returning to work and were not familiar with their rights on breastfeeding and maternity leave.Conclusion
Programmes for the protection, promotion and support of breastfeeding in these and similar regions of Italy should concentrate on better training of health professionals with regards to lactation management, communication, and counselling skills. The addition of trained peer counsellors could reinforce the work done by the health system and, through community involvement, could help change social prejudice in the mid- and long-term. The differences between regions should be taken into account in formulating these programmes to avoid increasing, and possibly to decrease, the current gaps. 相似文献10.
A Dickinson K Y Yeung J Donoghue M J Baker R DW Kelly M McKenzie T G Johns J C St. John 《Cell death and differentiation》2013,20(12):1644-1653
As stem cells undergo differentiation, mitochondrial DNA (mtDNA) copy number is strictly regulated in order that specialized cells can generate appropriate levels of adenosine triphosphate (ATP) through oxidative phosphorylation (OXPHOS) to undertake their specific functions. It is not understood whether tumor-initiating cells regulate their mtDNA in a similar manner or whether mtDNA is essential for tumorigenesis. We show that human neural stem cells (hNSCs) increased their mtDNA content during differentiation in a process that was mediated by a synergistic relationship between the nuclear and mitochondrial genomes and results in increased respiratory capacity. Differentiating multipotent glioblastoma cells failed to match the expansion in mtDNA copy number, patterns of gene expression and increased respiratory capacity observed in hNSCs. Partial depletion of glioblastoma cell mtDNA rescued mtDNA replication events and enhanced cell differentiation. However, prolonged depletion resulted in impaired mtDNA replication, reduced proliferation and induced the expression of early developmental and pro-survival markers including POU class 5 homeobox 1 (OCT4) and sonic hedgehog (SHH). The transfer of glioblastoma cells depleted to varying degrees of their mtDNA content into immunocompromised mice resulted in tumors requiring significantly longer to form compared with non-depleted cells. The number of tumors formed and the time to tumor formation was relative to the degree of mtDNA depletion. The tumors derived from mtDNA depleted glioblastoma cells recovered their mtDNA copy number as part of the tumor formation process. These outcomes demonstrate the importance of mtDNA to the initiation and maintenance of tumorigenesis in glioblastoma multiforme. 相似文献