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561.
Carboxyl terminal domain of Gs alpha specifies coupling of receptors to stimulation of adenylyl cyclase 总被引:13,自引:0,他引:13
S B Masters K A Sullivan R T Miller B Beiderman N G Lopez J Ramachandran H R Bourne 《Science (New York, N.Y.)》1988,241(4864):448-451
The alpha subunits of Gs and Gi link different sets of hormone receptors to stimulation and inhibition, respectively, of adenylyl cyclase. A chimeric alpha i/alpha s cDNA was constructed that encodes a polypeptide composed of the amino terminal 60% of an alpha i chain and the carboxyl terminal 40% of alpha s. The cDNA was introduced via a retroviral vector into S49 cyc- cells, which lack endogenous alpha s. Although less than half of the hybrid alpha chain is derived from alpha s, its ability to mediate beta-adrenoceptor stimulation of adenylyl cyclase matched that of the normal alpha s polypeptide expressed from the same retroviral vector in cyc- cells. This result indicates that carboxyl terminal amino acid sequences of alpha s contain the structural features that are required for specificity of interactions with the effector enzyme, adenylyl cyclase, as well as with the hormone receptor. 相似文献
562.
Gerardo A. Belandria Michael M. Pavletic James P. Boulay Dominique G. Penninck Leslie A. Schwarz 《The Canadian veterinary journal. La revue veterinaire canadienne》2009,50(7):733-740
Surgical stapling equipment was used to create a gastropexy in 20 dogs undergoing
emergency surgery for gastric dilatation and volvulus (GDV). The technique
involved creation of a tunnel between the seromuscular layer and the submucosa
of the pyloric antrum, and a matching tunnel beneath the right m. transversus
abdominis. The arms of a gastrointestinal anastomosis stapling device were
introduced into the tunnels, and the device was fired to create the gastropexy.
One dog died of systemic sequelae of GDV during the early postoperative period.
None of the remaining 19 dogs developed a recurrence of GDV during follow-up
periods ranging from 5 to 43 months. In 11 dogs, the integrity of the gastropexy
was evaluated by abdominal ultrasonography and either negative contrast
gastrography or double contrast gastrography; in these dogs, the radiographic
and/or the ultrasonographic findings were suggestive of an intact gastropexy.
There were no complications involving the gastropexy staple line. The results of
this study indicate that an effective and consistent permanent gastropexy can be
created, using surgical stapling equipment. 相似文献
563.
The absolute quantities and the stereoisomeric ratios of R, S-2-hydroxybutanone and R, R-, S, S-, R, S ( meso)-2,3-butanediol were determined in batteries of traditional balsamic vinegar (TBV) by gas chromatography-mass spectrometry (GC-MS), using a chiral capillary column, to evaluate if such parameters could be used to differentiate TBV differently aged and from different producers. Results showed that the initial amounts of 2-hydroxybutanone and 2,3-butanediol were quite variable, as a function of the producer of the vinegar; moreover, the 2-hydroxybutanone amount decreased during aging while 2,3-butanediol increased. Initially, the R-2-hydroxybutanone form prevails, and then the R/ S ratio decreased regularly during aging with some exceptions attributed to the addition of new barrels during the battery management. With regard to the 2,3-butanediol isomers, the most abundant was the R, R form, slowly transformed into the R, S and S, S isomers during aging. The GC-MS method used is easy and fast and could allow for a quick control of the maturation level of the vinegar. 相似文献
564.
Linking coastal aquaculture of meagre Argyrosomus regius and Western Mediterranean coastal fisheries through escapes incidents 下载免费PDF全文
P. Arechavala‐Lopez J. M. Valero‐Rodriguez J. Peñalver‐García D. Izquierdo‐Gomez P. Sanchez‐Jerez 《Fisheries Management and Ecology》2015,22(4):317-325
Escape incidents in coastal aquaculture lead to economic losses for farmers and may have indirect socio‐economic effects on local fisheries. In this study, the relationship of meagre, Argyrosomus regius (Asso), production in open‐sea cages and coastal small‐scale fisheries was analysed through captures of escapes, which are easily detected because this species is considered locally absent in native communities in Western Mediterranean regions. Scale reading showed that 100% of captured meagre were escapees. The existence of a direct relationship, in terms of biomass, between the development of meagre coastal aquaculture and the increase of captures of this species by local fisheries was demonstrated. The spatial distribution of meagre captures suggested that there is a local environmental and economic interaction between meagre aquaculture and fisheries through escapees. Monitoring the presence of locally absent species such as meagre within landings might help to assess the magnitude of escapes, the potential economic effects on local aquaculture and fishery industries, and the potential adverse ecological impacts on local ecosystems. 相似文献
565.
Juan Carlos Molinero Li‐Chun Tseng Lucia Lopez‐Lopez Ulrich Sommer Sami Souissi Jiang‐Shiou Hwang 《Fisheries Oceanography》2016,25(6):555-564
Global environmental changes threaten the sustainable use of resources and raise uncertainties regarding marine populations' responses in a changing Ocean. The pelagic copepods of the genus Calanus play a central role in shelf ecosystems transferring phytoplankton carbon to harvested populations, from boreal to temperate regions. Here we examined a 15‐yr time series of Calanus sinicus abundance in regards to climate forcing in the East China Sea. We identified a compound effect of the Pacific Decadal Oscillation (PDO) and the East Asian Winter Monsoon (EAWM) on environmental conditions in the East China Sea. Such climate influences not only a southward transport of C. sinicus from its population centres into the Taiwan area, but favours advantageous thermal conditions for the species as well. On the interannual scale, our results show that the population size of C. sinicus echoes climate‐driven temperature changes. Hence, the possibility of using the PDO and EAWM variability for assessing and predicting interannual abundance changes of C. sinicus in the East China Sea is considered. The observed close relationship between climate and C. sinicus may promote bottom‐up controls in the pelagic food web, further influencing the southern edge of the species' geographic distribution. Owing to the prominent role this species plays in food web dynamics these results might help integrative fisheries management policies in the heavily exploited East China Sea. 相似文献
566.
According to Greek mythology, Prometheus' liver grew back nightly after it was removed each day by an eagle as punishment for giving mankind fire. Hence, contrary to popular belief, the concept of tissue and organ regeneration is not new. In the early 20th century, cell culture and ex vivo organ preservation studies by Alexis Carrel, some with famed aviator Charles Lindbergh, established a foundation for much of modern regenerative medicine. While early beliefs and discoveries foreshadowed significant accomplishments in regenerative medicine, advances in knowledge within numerous scientific disciplines, as well as nano‐ and micromolecular level imaging and detection technologies, have contributed to explosive advances over the last 20 years. Virtually limitless preparations, combinations and applications of the 3 major components of regenerative medicine, namely cells, biomaterials and bioactive molecules, have created a new paradigm of future therapeutic options for most species. It is increasingly clear, however, that despite significant parallels among and within species, there is no ‘one‐size‐fits‐all’ regenerative therapy. Likewise, a panacea has yet to be discovered that completely reverses the consequences of time, trauma and disease. Nonetheless, there is no question that the promise and potential of regenerative medicine have forever altered medical practices. The horse is a relative newcomer to regenerative medicine applications, yet there is already a large body of work to incorporate novel regenerative therapies into standard care. This review focuses on the current state and potential future of stem cells in equine regenerative medicine. 相似文献