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21.
Yara A. Alshwairikh Shayla L. Kroeze Jenny Olsson Steve A. StephensCardenas William L. Swain Lisette P. Waits Rebekah L. Horn Shawn R. Narum Travis Seaborn 《Ecology and evolution》2021,11(23):16890
Many species that undergo long breeding migrations, such as anadromous fishes, face highly heterogeneous environments along their migration corridors and at their spawning sites. These environmental challenges encountered at different life stages may act as strong selective pressures and drive local adaptation. However, the relative influence of environmental conditions along the migration corridor compared with the conditions at spawning sites on driving selection is still unknown. In this study, we performed genome–environment associations (GEA) to understand the relationship between landscape and environmental conditions driving selection in seven populations of the anadromous Chinook salmon (Oncorhynchus tshawytscha)—a species of important economic, social, cultural, and ecological value—in the Columbia River basin. We extracted environmental variables for the shared migration corridors and at distinct spawning sites for each population, and used a Pool‐seq approach to perform whole genome resequencing. Bayesian and univariate GEA tests with migration‐specific and spawning site‐specific environmental variables indicated many more candidate SNPs associated with environmental conditions at the migration corridor compared with spawning sites. Specifically, temperature, precipitation, terrain roughness, and elevation variables of the migration corridor were the most significant drivers of environmental selection. Additional analyses of neutral loci revealed two distinct clusters representing populations from different geographic regions of the drainage that also exhibit differences in adult migration timing (summer vs. fall). Tests for genomic regions under selection revealed a strong peak on chromosome 28, corresponding to the GREB1L/ROCK1 region that has been identified previously in salmonids as a region associated with adult migration timing. Our results show that environmental variation experienced throughout migration corridors imposed a greater selective pressure on Chinook salmon than environmental conditions at spawning sites. 相似文献
22.
Tamer Z. Salem Craig P. Seaborn Colin M. Turney Jianli Xue Hui Shang Xiao-Wen Cheng 《PloS one》2015,10(12)
The simian virus 40 polyadenylation signal (SV40 polyA) has been routinely inserted downstream of the polyhedrin promoter in many baculovirus expression vector systems (BEVS). In the baculovirus prototype Autographa californica multiple nucleopolyhedrovirus (AcMNPV), the polyhedrin promoter (very late promoter) transcribes its gene by a viral RNA polymerase therefore there is no supporting evidence that SV40 polyA is required for the proper gene expression under the polyhedrin promoter. Moreover, the effect of the SV40 polyA sequence on the polyhedrin promoter activity has not been tested either at its natural polyhedrin locus or in other loci in the viral genome. In order to test the significance of adding the SV40 polyA sequence on gene expression, the expression of the enhanced green fluorescent protein (egfp) was evaluated with and without the presence of SV40 polyA under the control of the polyhedrin promoter at different genomic loci (polyherin, ecdysteroid UDP-glucosyltransferase (egt), and gp37). In this study, spectrofluorometry and western blot showed reduction of EGFP protein for all recombinant viruses with SV40 polyA, whereas qPCR showed an increase in the egfp mRNA levels. Therefore, we conclude that SV40 polyA increases mRNA levels but decreases protein production in the BEVS when the polyhedrin promoter is used at different loci. This work suggests that SV40 polyA in BEVSs should be replaced by an AcMNPV late gene polyA for optimal protein production or left untouched for optimal RNA production (RNA interference applications). 相似文献
23.
Maltais F Seaborn T Guay S Piedboeuf B 《American journal of physiology. Lung cellular and molecular physiology》2003,284(4):L622-L632
Fetal tracheal occlusion (TO) reverses lung hypoplasia by inducing rapid lung growth. Although increases in lung size accompanied by increased numbers of alveoli and capillaries have been reported, effects of TO on lung development have not been formally assessed. In the present study, the objective was to verify our prediction that the main effect of TO would be to accelerate fetal lung development. We have developed and characterized a new fetal mouse model of TO to best realize this goal. At embryonic day 16.5, pregnant CD1 mice were operated under general anesthesia. One fetus per dam was selected to undergo surgical TO with a surgical clip or a sham operation. The fetuses were delivered 24 or 36 h postsurgery. The maturation of lung parenchyma, evaluated by counting the generations of alveolar saccules from the terminal bronchiole to the pleura, was significantly accelerated in the TO group with a complexity of the gas exchange region comparable with postnatal days 1 and 3 after 24 or 36 h of TO. Cellular proliferation and apoptosis peaks, assessed by immunohistochemistry directed against PCNA and the active form of caspase-3, were significantly increased 24 h after surgery in the TO group compared with the sham group. However, in situ hybridization showed no significant difference in the density of type II pneumocytes expressing surfactant protein C mRNA. Our results show that brief TO during late gestation in fetal mice induces accelerated lung development with minimal effects on surfactant protein C mRNA expression. 相似文献
24.
25.
Howe GT; Bucciaglia PA; Hackett WP; Furnier GR; Cordonnier-Pratt MM; Gardner G 《Molecular biology and evolution》1998,15(2):160-175
The phytochrome photoreceptors play important roles in the photoperiodic
control of vegetative bud set, growth cessation, dormancy induction, and
cold-hardiness in trees. Interestingly, ecotypic differences in
photoperiodic responses are observed in many temperate- zone tree species.
Northern and southern ecotypes of black cottonwood (Populus trichocarpa
Torr. & Gray), for example, exhibit marked differences in the timing of
short-day-induced bud set and growth cessation, and these responses are
controlled by phytochrome. Therefore, as a first step toward determining
the molecular genetic basis of photoperiodic ecotypes in trees, we
characterized the phytochrome gene (PHY) family in black cottonwood. We
recovered fragments of one PHYA and two PHYB using PCR-based cloning and by
screening a genomic library. Results from Southern analyses confirmed that
black cottonwood has one PHYA locus and two PHYB loci, which we arbitrarily
designated PHYB1 and PHYB2. Phylogenetic analyses which included PHY from
black cottonwood, Arabidopsis thaliana and tomato (Solanum lycopersicum)
suggest that the PHYB/D duplications in these species occurred
independently. When Southern blots were probed with PHYC, PHYE, and PHYE
heterologous probes, the strongest bands that we detected were those of
black cottonwood PHYA and/or PHYB. These results suggest that black
cottonwood lacks members of the PHYC/F and PHYE subfamilies. Although black
cottonwood could contain additional PHY that are distantly related to known
angiosperm PHY, our results imply that the PHY family of black cottonwood
is less complex than that of other well-characterized dicot species such as
Arabidopsis and tomato. Based on Southern analyses of five black cottonwood
genotypes representing three photoperiodic ecotypes, substantial
polymorphism was detected for at least one of the PHYB loci but not for the
PHYA locus. The novel character of the PHY family in black cottonwood, as
well as the differences in polymorphism we observed between the PHYA and
PHYB subfamilies, indicates that a number of fundamental macro- and
microevolutionary questions remain to be answered about the PHY family in
dicots.
相似文献
26.
Molybdenum (Mo) supplementation reduces the incidence of nitrosamine-induced tumors in the esophagus and forestomach of laboratory
animals, and the incidence of mammary cancer in female rats induced byN-nitroso-N-methylurea (NMU). The present study was conducted to evaluate the effect of graded amounts of Mo on NMU-induced mammary carcinogenesis,
and on the excretion of Mo and copper (Cu). Female Sprague-Dawley rats aged 5 wk were givenad libitum a low-Mo (0.026 mg/kg) diet and deionized water. After 15 d, a single SC injection of 50 mg NMU/kg body wt was administered
to each of 30 rats in groups 2–5. Eight rats in group 1 served as untreated control. One week after the carcinogen treatment,
0.1, 1.0, or 10 mg Mo from sodium molybdate were added to each liter of drinking water for groups 3, 4, and 5, respectively.
Groups 1 and 2 did not receive any Mo supplementation. After the rats had been Mosupplemented for 38, 67, and 85 d, 48-h urine
and fecal samples were collected from the same 48 rats, and Mo and Cu were determined. Molybdenum seemed to have little effect
on Cu excretion. At each time interval, animals fed 0 or 0.1 mg Mo/L excreted more Mo in feces than in urine, whereas rats
fed 1 and 10 mg Mo/L water excreted more Mo in urine than in feces, which indicates that Mo absorption was not easily saturated
as the amount of Mo increased. However, the liver became saturated with Mo when 0.1–1 mg Mo/L was fed. The total number of
palpable tumors per group 101 d after NMU administration was 109, 115, 101, and 81, and the total carcinomas per group were
92, 96, 86, and 65 for the animals in groups 2–5, respectively. The results indicate that supplemental Mo in the amount of
10 mg/L of drinking water inhibited mammary carcinogenesis. 相似文献
27.
M.A. Frohn C.J. Seaborn D.W. Johnson G. Phillipou R.F. Seamark C.D. Matthews 《Life sciences》1980,27(22):2043-2046
Analysis of the structure-activity relationship between twenty-three indoleamines and melatonin, based on a specific fish bioassay, is described. The results clearly define that only halogenation at position 6 or extension of the acetyl side-chain to propionyl or butyryl is tolerated without a decrease in activity. Removal of the indole double bond however, only leads to a less than ten-fold loss of activity. The over-all relevance of the data in the development of a metabolically stable melatonin agonist is discussed. 相似文献
28.
We have shown that silicon (Si) deprivation decreases the collagen concentration in bone of 9-wk-old rats. Finding that Si
deprivation also affects collagen at different stages in bone development, collagen-forming enzymes, or collagen deposition
in other tissues would have implications that Si is important for both wound healing and bone formation. Therefore, 42 rats
in experiment 1 and 24 rats in experiment 2 were fed a basal diet containing 2 or 2.6 μg Si/g, respectively, based on ground
corn and casein, and supplemented with either 0 or 10 μg Si/g as sodium metasilicate. At 3 wk, the femur was removed from
18 of the 42 rats in experiment 1 for hydroxyproline analysis. A polyvinyl sponge was implanted beneath the skin of the upper
back of each of the 24 remaining rats. Sixteen hours before termination and 2 wk after the sponge had been implanted, each
rat was given an oral dose of 14C-proline (1.8 μCi/100 g body wt). The total amount of hydroxyproline was significantly lower in the tibia and sponges taken
from Si-deficient animals than Si-supplemented rats. The disintegrations per minute of 14C-proline were significantly higher in sponge extracts from Si-deficient rats than Si-supplemented rats. Additional evidence
of aberrations in proline metabolism with Si deprivation was that liver ornithine aminotransferase was significantly decreased
in Si-deprived animals in experiment 2. Findings of an increased accumulation of 14C-proline and decreased total hydroxyproline in implanted sponges and decreased activity of a key enzyme in proline synthesis
(liver ornithine aminotransferase) in Si-deprived animals indicates an aberration in the formation of collagen from proline
in sites other than bone that is corrected by Si. This suggests that Si is a nutrient of concern in wound healing as well
as bone formation.
The U.S. Department of Agriculture, Agricultural Research Service, Northern Plains Area is an equal opportunity/affirmative
action employer, and all agency services are available without discrimination.
Mention of a trademark or proprietary product does not constitute a guarantee or warranty of the product by the US Department
of Agriculture and does not imply its approval to the exclusion of other products that may be suitable. 相似文献
29.
Antagonistic interactions between silicon and aluminum occur in living organisms. Thus, an experiment was performed to ascertain whether high dietary aluminum would accentuate the signs of silicon deprivation in rats and conversely whether silicon deprivation would accentuate the response to high dietary aluminum. The experiment was factorially arranged with two variables: silicon as sodium metasilicate, 0 or 40 μg/g diet, and aluminum as aluminum citrate, 0 or 500 μg/g diet. After 9 wk, body weights and plasma urea nitrogen were higher and plasma concentrations of threonine, serine, glycine, cystine, and methionine were lower in silicon-adequate than silicon-deprived rats. High dietary aluminum significantly decreased plasma phenylalanine. An interaction between aluminum and silicon affected plasma triglyceride, cholesterol, and phosphorus concentrations. High dietary aluminum decreased these variables when silicon was absent from the diet, but increased them when silicon was present. Skull iron and silicon concentrations were decreased and iron and zinc concentrations in the femur were increased by the addition of 500 μg Al/g diet. High dietary aluminum decreased tibia density in silicon-adequate rats, but increased tibial density in silicon-deprived rats. The findings indicate that in rats, high dietary aluminum can affect the response to silicon deprivation and dietary silicon can affect the response to high dietary aluminum. 相似文献
30.
Carol D. Seaborn Nancy Cheng Bernice Adeleye Fred Owens Barbara J. Stoecker 《Biological trace element research》1994,41(3):279-294
Chromium (Cr) potentiates the effects of insulin and a role for insulin in ascorbic acid transport has been reported. Therefore, the effects of Cr and ascorbate depletion on tissue ascorbic acid and14C distribution and excretion after a14C ascorbate dose were investigated in guinea pigs. As utilization of dietary Cr is affected by interaction with other minerals, tissue manganese (Mn), zinc (Zn), copper (Cu), and iron (Fe) were examined. For 20 wk, 40 weanling animals were fed either a Cr-deficient (<0.06 μg Cr/g diet, ?Cr) or a Cr-adequate (2 μg Cr from CrCl3/g diet, +Cr) casein-based diet and were given 1 mg ascorbate/d (?C) or 10 mg ascorbate/d (+C) for 20 wk. Animals fed the Cr-depleted diet had decreased weight at 20 wk (p<0.01). Six hours before necropsy, animals were dosed by micropipette with 1.8 μCi ofl-[carboxyl-14C] ascorbic acid and placed in metabolic cages. Ascorbate supplementation increased Fe concentrations in most analyzed tissues, hepatic14C, tissue ascorbate and Mn concentration in the adrenal and testes, but decreased the concentrations of Cu in the kidney and Mn in the spleen. Liver Mn concentration was higher and kidney Mn concentration was lower in +Cr animals. Interactions between Cr and ascorbic acid affected Mn concentrations in bone and brain. These results indicate that ascorbate and Cr may affect Mn distribution. Chromium supplementation decreased plasma cortisol, brain14C and the amount of14C expired as carbon dioxide. These findings suggest that dietary Cr may affect ascorbic acid metabolism and the metabolic response to stress. 相似文献