排序方式: 共有235条查询结果,搜索用时 546 毫秒
61.
Effects of progesterone and estradiol on the reproductive axis in immature diploid and triploid rainbow trout 总被引:1,自引:0,他引:1
Atteke C Vetillard A Fostier A Garnier DH Jego P Bailhache T 《Comparative biochemistry and physiology. Part A, Molecular & integrative physiology》2003,134(4):693-705
In fish species, many studies demonstrated the crucial role of estradiol (E2) in the development of the reproductive axis, but progesterone (P) has been described mainly as a precursor steroid and no clear role by itself has been reported. Moreover, a cooperative effect of P (or another progestin) and E2 in fish has never been reported to our knowledge. In the present work, we investigated the effects of P, alone or in combination with E2, on the reproductive-axis of immature rainbow trout (Oncorhynchus mykiss). Liver vitellogenin and estradiol receptor (rtER) mRNA levels increased after E2 treatment, but were unchanged by P treatments as a reflection of peripheral action of steroids. In contrast, at the pituitary level, LH contents increased after E2 and/or P treatments. Focusing on the brain level, we confirmed a clear up regulation of rtER expression by E2 in sterile triploid females, and we also demonstrated a similar stimulating effect of P alone but no cooperative effect together with E2. In conclusion, our data demonstrate that in immature trout, prior to the beginning of the first reproductive cycle, unlike E2, P is able to stimulate the reproductive brain-pituitary axis without affecting vitellogenin synthesis in the liver. 相似文献
62.
p115 Rho GTPase activating protein interacts with MEKK1 总被引:1,自引:0,他引:1
Christerson LB Gallagher E Vanderbilt CA Whitehurst AW Wells C Kazempour R Sternweis PC Cobb MH 《Journal of cellular physiology》2002,192(2):200-208
Mammalian MAP/ERK kinase kinase 1 (MEKK1) was identified as a mammalian homolog of Ste11p of the yeast pheromone-induced mating pathway. Like Ste11p, MEKK1 is a MAP3 kinase linked to at least two MAP kinase cascades and regulatory events that require cytoskeletal reorganization. MEKK1 is activated by molecules that impact cytoskeletal function. MEKK1-/-cells are defective in cell migration, demonstrating that it is required for cell motility. MEKK1 has a 1,200 residue N-terminal regulatory domain that interacts with a dozen identified proteins. Using part of the MEKK1 N-terminus in a yeast two-hybrid screen, we discovered a novel interaction with p115 Rho GTPase-activating protein (GAP). The p115 Rho GAP binds to MEKK1 in vitro and in intact cells. The p115 Rho GAP has selectivity for RhoA over other Rho family members. Expression of p115 Rho GAP reduces MEKK1-induced signaling to AP-1. The reduced activation of AP-1 is dependent on the association of MEKK1 with p115 Rho GAP, because deletion of the Rho GAP SH3 domain, which abrogates their interaction, restores the stimulatory effect of MEKK1 on AP-1 activity. Here we have identified an MEKK1 binding partner that offers a connection between this protein kinase and the machinery regulating cytoskeletal reorganization. 相似文献
63.
The clustering of acetylcholine receptors (AChRs) in skeletal muscle fibers is a critical event in neuromuscular synaptogenesis. AChRs in concert with other molecules form postsynaptic scaffolds in response to agrin released from motor neurons as motor neurons near skeletal muscle fibers in development. Agrin drives an intracellular signaling pathway that precedes AChR clustering and includes the tyrosine phosphorylation of AChRs. In C2C12 myotube culture, agrin application stimulates the agrin signaling pathway and AChR clustering. Previous studies have determined that the frequency of spontaneous AChR clustering is decreased and AChRs are partially inactivated when bound by the acetylcholine agonist nicotine. We hypothesized that nicotine interferes with AChR clustering and consequent postsynaptic scaffold formation. In the present study, C2C12 myoblasts were cultured with growth medium to stimulate proliferation and then differentiation medium to stimulate fusion into myotubes. They were bathed in a physiologically relevant concentration of nicotine and then subject to agrin treatment after myotube formation. Our results demonstrate that nicotine decreases agrin-induced tyrosine phosphorylation of AChRs and decreases the frequency of spontaneous as well as agrin-induced AChR clustering. We conclude that nicotine interferes with postsynaptic scaffold formation by preventing the tyrosine phosphorylation of AChRs, an agrin signaling event that precedes AChR clustering. 相似文献
64.
Novel replication-incompetent vector derived from adenovirus type 11 (Ad11) for vaccination and gene therapy: low seroprevalence and non-cross-reactivity with Ad5 总被引:5,自引:0,他引:5 下载免费PDF全文
Holterman L Vogels R van der Vlugt R Sieuwerts M Grimbergen J Kaspers J Geelen E van der Helm E Lemckert A Gillissen G Verhaagh S Custers J Zuijdgeest D Berkhout B Bakker M Quax P Goudsmit J Havenga M 《Journal of virology》2004,78(23):13207-13215
A novel plasmid-based adenovirus vector system that enables manufacturing of replication-incompetent (DeltaE1) adenovirus type 11 (Ad11)-based vectors is described. Ad11 vectors are produced on PER.C6/55K cells yielding high-titer vector batches after purification. Ad11 seroprevalence proves to be significantly lower than that of Ad5, and neutralizing antibody titers against Ad11 are low. Ad11 seroprevalence among human immunodeficiency virus-positive (HIV(+)) individuals is as low as that among HIV(-) individuals, independent of the level of immune suppression. The low level of coinciding seroprevalence between Ad11 and Ad35 in addition to a lack of correlation between high neutralizing antibody titers towards either adenovirus strongly suggest that the limited humoral cross-reactive immunity between these two highly related B viruses appears not to preclude the use of both vectors in the same individual. Ad11 transduces primary cells including smooth muscle cells, synoviocytes, and dendritic cells and cardiovascular tissues with higher efficiency than Ad5. Ad11 and Ad35 appear to have a similar tropism as judged by green fluorescent protein expression levels determined by using a panel of cancer cell lines. In addition, Ad5 preimmunization did not significantly affect Ad11-mediated transduction in C57BL/6 mice. We therefore conclude that the Ad11-based vector represents a novel and useful candidate gene transfer vehicle for vaccination and gene therapy. 相似文献
65.
66.
67.
Immunogenicity of recombinant fiber-chimeric adenovirus serotype 35 vector-based vaccines in mice and rhesus monkeys 下载免费PDF全文
Nanda A Lynch DM Goudsmit J Lemckert AA Ewald BA Sumida SM Truitt DM Abbink P Kishko MG Gorgone DA Lifton MA Shen L Carville A Mansfield KG Havenga MJ Barouch DH 《Journal of virology》2005,79(22):14161-14168
Preexisting immunity to adenovirus serotype 5 (Ad5) has been shown to suppress the immunogenicity of recombinant Ad5 (rAd5) vector-based vaccines for human immunodeficiency virus type 1 (HIV-1) in both preclinical studies and clinical trials. A potential solution to this problem is to utilize rAd vectors derived from rare Ad serotypes, such as Ad35. However, rAd35 vectors have appeared less immunogenic than rAd5 vectors in preclinical studies to date. In this study, we explore the hypothesis that the differences in immunogenicity between rAd5 and rAd35 vectors may be due in part to differences between the fiber proteins of these viruses. We constructed capsid chimeric rAd35 vectors containing the Ad5 fiber knob (rAd35k5) and compared the immunogenicities of rAd5, rAd35k5, and rAd35 vectors expressing simian immunodeficiency virus Gag and HIV-1 Env in mice and rhesus monkeys. In vitro studies demonstrated that rAd35k5 vectors utilized the Ad5 receptor CAR rather than the Ad35 receptor CD46. In vivo studies showed that rAd35k5 vectors were more immunogenic than rAd35 vectors in both mice and rhesus monkeys. These data suggest that the Ad5 fiber knob contributes substantially to the immunogenicity of rAd vectors. Moreover, these studies demonstrate that capsid chimeric rAd vectors can be constructed to combine beneficial immunologic and serologic properties of different Ad serotypes. 相似文献
68.
The genetic population structure of wild western lowland gorillas (Gorilla gorilla gorilla) living in continuous rain forest 下载免费PDF全文
Tillmann Fünfstück Mimi Arandjelovic David B. Morgan Crickette Sanz Thomas Breuer Emma J. Stokes Patricia Reed Sarah H. Olson Ken Cameron Alain Ondzie Martine Peeters Hjalmar S. Kühl Chloe Cipolletta Angelique Todd Shelly Masi Diane M. Doran‐Sheehy Brenda J. Bradley Linda Vigilant 《American journal of primatology》2014,76(9):868-878
69.
Angelique Corthals Alynn Martin Omar M. Warsi Megan Woller-Skar Winston Lancaster Amy Russell Liliana M. Dávalos 《PloS one》2015,10(3)
Studies in molecular ecology depend on field-collected samples for genetic information, and the tissue sampled and preservation conditions strongly affect the quality of the DNA obtained. DNA yields from different tissue types have seldom been compared, and the relative performance of storage media has never been directly tested, even though these media may influence DNA degradation under field conditions. We analyzed DNA yield from buccal swabs and wing punches harvested from live bats using nucleic acid quantification as well as quantitative PCR for a single-copy nuclear locus. We also compared DNA yields from wing tissue preserved in three media: ethanol, NaCl-saturated dimethyl sulfoxide (DMSO), and silica desiccant. Wing punches yielded more total DNA than did buccal swabs, and wing tissues preserved in silica beads yielded significantly more total and nuclear DNA than those preserved in DMSO or ethanol. These results show that tissue type and preservation media strongly influence the quantity of DNA obtained from non-lethal genetic samples, and based on these effects we provide recommendations for field collection of tissues for genetic analyses. 相似文献
70.
Ga?l Mourembou Florence Fenollar Jean Bernard Lekana-Douki Angelique Ndjoyi Mbiguino Sydney Maghendji Nzondo Pierre Blaise Matsiegui Rella Zoleko Manego Cyrille Herve Bile Ehounoud Fadi Bittar Didier Raoult Oleg Mediannikov 《PLoS neglected tropical diseases》2015,9(10)