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61.
The insulin/IGF-1 (where IGF-1 is insulin-like growth factor-1) signaling pathway influences longevity, reproduction, and diapause in many organisms. Because of the fundamental importance of this system in animal physiology, we asked when during the animal's life it is required to regulate these different processes. We find that in Caenorhabditis elegans, the pathway acts during adulthood, to relatively advanced ages, to influence aging. In contrast, it regulates diapause during development. In addition, the pathway controls longevity and reproduction independently of one another. Together our findings show that life-span regulation can be dissociated temporally from phenotypes that might seem to decrease the quality of life. 相似文献
62.
Douglas R. Tocher 《Fish physiology and biochemistry》1990,8(3):239-249
The incorporation and metabolism of various (n-3) and (n-6) polyunsaturated fatty acids supplemented to the culture medium
was investigated in the rainbow trout cell line, RTG-2. The distribution, and the occurrence and relative extent of further
desaturation and elongation of the incorporated acids was determined in individual phospholipid classes by analysis of the
fatty acid compositions. RTG-2 cells exhibited Δ6 and Δ5 desaturase activities whereas Δ4 desaturase activity was almost totally
absent. The percentage of precursor acids was greatest in the phosphatidic acid/cardiolipin fraction (PA/CL), suggesting a
role for possibly PA in the initial incorporation of these acids into the phospholipid pool. The compositional data indicated
that individual intermediates and products of the desaturation pathways were associated with specific phospholipid classes
probably via mechanisms depending upon the specificities of the acylating enzymes. The composition of phosphatidylinositol
(PI) and the tightly controlled mechanisms for generating/maintaining it are consistent with a role for this phospholipid
in providing precursor fatty acid for eicosanoid synthesis. 相似文献
63.
Futuyma DJ 《Science (New York, N.Y.)》2012,336(6083):816
64.
Sreedharan J Blair IP Tripathi VB Hu X Vance C Rogelj B Ackerley S Durnall JC Williams KL Buratti E Baralle F de Belleroche J Mitchell JD Leigh PN Al-Chalabi A Miller CC Nicholson G Shaw CE 《Science (New York, N.Y.)》2008,319(5870):1668-1672
Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disorder characterized pathologically by ubiquitinated TAR DNA binding protein (TDP-43) inclusions. The function of TDP-43 in the nervous system is uncertain, and a mechanistic role in neurodegeneration remains speculative. We identified neighboring mutations in a highly conserved region of TARDBP in sporadic and familial ALS cases. TARDBPM337V segregated with disease within one kindred and a genome-wide scan confirmed that linkage was restricted to chromosome 1p36, which contains the TARDBP locus. Mutant forms of TDP-43 fragmented in vitro more readily than wild type and, in vivo, caused neural apoptosis and developmental delay in the chick embryo. Our evidence suggests a pathophysiological link between TDP-43 and ALS. 相似文献
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66.
ABSTRACT Thirteen aphid species were tested for their ability to transmit Pennsylvania isolates of Plum pox virus (PPV) collected in Columbia (PENN-3), Franklin (PENN-4), and York (PENN-7) Counties, PA. Four species, Aphis fabae, A. spiraecola, Brachycaudus persicae, and Myzus persicae, consistently transmitted PPV in preliminary transmission tests. Two species, Metopolophium dirhodum and Rhopalosiphum padi, were occasional inefficient vectors. Toxoptera citricida, from Florida, also was an effective vector but it does not occur in major stone-fruit-growing states. Species not transmitting PPV in parallel tests included Acyrthosiphon pisum, Aphis glycines, Aulacorthum solani, Macrosiphum euphorbiae, Rhopalosiphum maidis, and Sitobion avenae. When given a 3-day probing access period simultaneously on PPV-infected peach seedlings and healthy peach seedlings, Myzus persicae, Aphis spiraecola, A. fabae, and B. persicae transmitted PPV to 63, 31, 38, and 32% of the healthy peach seedlings, respectively. When given a similar probing period on PPV-infected peach fruit and healthy peach seedlings, the same aphid species transmitted PPV to 50, 35, 0, and 0% of seedlings, respectively. Results support the hypothesis of secondary PPV spread by indigenous aphids in Pennsylvania, and suggest that PPV-infected fruit has the potential to function as a virus source for long-distance dispersal. 相似文献
67.
Heffelfinger DJ 《The Canadian veterinary journal. La revue veterinaire canadienne》2006,47(2):165-167
A 2-year-old domestic shorthair queen was presented for recurrent estrus behavior. Ovariohysterectomy had been performed 9 months earlier. An ovarian remnant was diagnosed, based on vaginal cytology and hormonal stimulation. Following exploratory laparotomy to remove the aberrant tissue, the animal recovered without further complications. 相似文献
68.
Douglas J. Bruggeman Thorsten Wiegand Jeffrey R. Walters Fernando González Taboada 《Landscape Ecology》2014,29(4):639-653
Dispersal is a critical biological process that contributes to the persistence of species in complex and dynamic landscapes. However, little is known about the ability of different types of data to reveal how species interact with landscape patterns during dispersal. Further, application of process-based, landscape-scale models able to capture the influence of land use and climate change are limited by this lack of dispersal knowledge. Here we highlight a method for building such models when dispersal parameters are unknown, but information on the mating system and survival are available. We applied a common statistical framework, rooted in information theory, to contrast the ability of abundance, movement, and genetic data to estimate dispersal parameters for endangered Red-cockaded woodpecker (RCW), using an individual-based, spatially-explicit population model. Dispersal was modeled as a multifaceted process in which foray distance, long-distance dispersal, competition for mates, and landscape permeability were treated as uncertain. We found that movement data are three-times more powerful than abundance data collected at the same spatial and temporal scales. However, habitat occupancy data collected over much a shorter time scale but at regional spatial scales were very effective for estimating dispersal. We also found that one-year of abundance data provided a similar reduction in uncertainty as genetic differences among breeding groups estimated using a 24-year pedigree. Substituting population genetic data for movement and abundance data often led to the same parameter values, but not always. Our study highlights important differences in the information content of data commonly collected in the field. 相似文献
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