首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.

Background

Newly weaned horses in Finland are often moved to unheated loose housing systems in which the weanlings have free access to a paddock and a shelter. This practice is considered to be good for the development of young horses. The daily temperatures can stay below ? 20 °C in Finland for several consecutive weeks during the winter season. However, the effect of unheated housing in a cold climatic environment on the respiratory health of weanlings under field conditions has not been studied before. This investigation was an observational field-study comprising 60 weanlings among 11 different voluntary participant rearing farms in Finland. Weanlings were either kept in unheated loose housing systems (n = 36) or in stables (n = 24) and were clinically examined on two separate occasions 58 days apart in cold winter conditions.

Results

The odds of clinical respiratory disease were lower in the older foals (loge days); OR = 0.009, P = 0.044). The plasma fibrinogen concentration was higher when the available space (m2/weanling) in the sleeping hall was smaller (P = 0.014) and it was lower when the sleeping hall was not insulated (P = 0.010). The plasma fibrinogen concentrations at the second examination were lower with a body condition score above 3 (P = 0.070). Standardbreds kept in loose housing systems had a lower body condition score than Finnhorses or Standardbreds kept in stables at both examinations (P = 0.026 and P = 0.007, respectively). Haemoglobin level was lower in weanlings in loose housing systems compared to their counterparts at the first examination (P = 0.037). Finnhorses had higher white blood cell count than Standardbreds at first (P = 0.002) and at the second examination (P = 0.001).

Conclusions

Keeping weanling horses in cold loose housing systems does not seem to increase the occurrence of respiratory disease, but special attention should be focused on ventilation, air quality and feeding-practices. Our field study data suggest it might be advantageous to keep Standardbred foals born late in the season in a stable over the Finnish winter.
  相似文献   

2.
One-season fallows with legumes such as Crotalaria grahamiana Wight & Arn. and phosphorus (P) fertilization have been suggested to improve crop yields in sub-Saharan Africa. Assessing the sustainability of these measures requires a sound understanding of soil processes, especially transformations of P which is often the main limiting nutrient. We compared plant production, nitrogen (N) and P balances and selected soil properties during 5.5 years in a field experiment with three crop rotations (continuous maize, maize-crotalaria and maize-natural fallow rotation) at two levels of P fertilization (0 and 50 kg P ha?1 yr?1, applied as triple superphosphate) on a Kandiudalfic Eutrudox in western Kenya. The maize yield forgone during growth of the crotalaria fallow was compensated by higher post-fallow yields, but the cumulative total maize yield was not significantly different from continuous maize. In all crop rotations, P fertilization doubled total maize yields, increased N removal by maize and remained without effect on amounts of recycled biomass. Crotalaria growth decreased in the course of the experiment due to pest problems. The highest levels of soil organic and microbial C, N and P were found in the maize-crotalaria fallow rotation. The increase in organic P was not accompanied by a change in resin-extractable P, while H2SO4-extractable inorganic P was depleted by up to 38 kg P ha?1 (1% of total P) in the 0–50 cm layer. Microbial P increased substantially when soil was supplied with C and N in a laboratory experiment, confirming field observations that the microbial biomass is limited by C and N rather than P availability. Maize-legume fallow rotations result in a shift towards organic and microbial nutrients and have to be complemented by balanced additions of inorganic fertilizers. Abbreviations: BNF – biological nitrogen fixation; COM – continuous maize; LR – long rainy season; MCF – maize-crotalaria fallow rotation; MNF – maize-natural fallow rotation; SR – short rainy season; TSP – triple superphosphate.  相似文献   

3.
Understanding patterns of genetic diversity and population structure for rare, narrowly endemic plant species, such as Pinguicula ionantha (Godfrey’s butterwort; Lentibulariaceae), informs conservation goals and can directly affect management decisions. Pinguicula ionantha is a federally listed species endemic to the Florida Panhandle in the southeastern USA. The main goal of our study was to assess patterns of genetic diversity and structure in 17 P. ionantha populations, and to determine if diversity is associated with geographic location or population characteristics. We scored 240 individuals at a total of 899 AFLP markers (893 polymorphic markers). We found no relationship between the estimated population size with either of two measures of diversity (proportion of loci polymorphic, P = 0.37; Nei’s gene diversity, P = 0.50). We also found low levels of population genetic structure; there was no clear relationship of genetic isolation by distance (P = 0.23) and only a small (but significant) proportion of genetic variation was partitioned amongst regions (2.4 %, P = 0.02) or populations (20.8 %, P < 0.001). STRUCTURE analysis found that the model with two inferred clusters (K = 2) best described the AFLP data; the dominant cluster at each site corresponded to the results from PCoA and Nei’s genetic distance analyses. The observed patterns of genetic diversity suggest that although P. ionantha populations are isolated spatially by distance and both natural and anthropogenic barriers, some gene flow occurs among them or isolation has been too recent to leave a genetic signature. The relatively low level of genetic diversity associated with this species is a concern as it may impair fitness and evolutionary capability in a changing environment. The results of this study provide the foundation for the development of management practices that will assist in the protection of this rare carnivorous plant.  相似文献   

4.

Objects

To explore the roles of growth factor receptor-bound protein 14 (GRB14) in colorectal cancer (CRC) and its correlation with clinicopathological characteristics and prognosis of CRC patients.

Results

GRB14 was localized in the cytoplasm of CRC and benign glandular epithelium cells, showing higher levels in CRC tissues compared with normal colon samples (P < 0.001). High GRB14 was associated with a high pathological grade (P = 0.045), advanced clinical stage (P = 0.018), enhanced tumor invasion (P < 0.001) and lymph node metastasis (P = 0.028). The cancer genome atlas (TCGA) mRNA sequence data showed that GRB14 was upregulated in CRC at an advanced clinical stage (P = 0.011) with enhanced tumor invasion (P < 0.001) and lymph node metastasis (P = 0.014). Kaplan–Meier survival curves revealed that CRC patients with high GRB14 levels had a shorter survival compared with those showing low GRB14 expression (P = 0.007). High GRB14 expression was an independent prognostic factor for CRC patients (HR 2.847, 95 %CI 1.058–7.659; P = 0.038).

Conclusions

GRB14 may be an important cancer promoter that enhances CRC progression. Upregulated GRB14 levels may predict a poor clinical outcome in CRC patients.
  相似文献   

5.
Wetland restoration provides many benefits, but re-flooding historically drained land can have unintended negative consequences, including phosphorus (P) release from sediments. To investigate the effects of re-flooding on P cycling, this study monitored a restoration in Michigan that back-flooded old drainage ditches and re-flooded former wetland soils. Immediately after re-flooding, previously exposed sediments released substantial amounts of P to the water column. Soluble reactive phosphorus (SRP) concentrations in re-flooded areas were as high as 750 μg P l?1. At peak P concentrations, there were about 20 times more SRP and 14 times more total P in the surface water than in the much smaller flooded area that existed before re-flooding. Prolific growth of filamentous algae and duckweed was observed in subsequent summers. Sedimental analyses suggest that most of the P released originated from iron-bound fractions. The highest SRP concentrations occurred during the first year when surface water dissolved oxygen was low (<5.5 mg l?1). Similarly low oxygen in the second year after flooding was not associated with such high P concentrations. After 1 year postflooding, SRP concentrations remained below 50 μg P l?1 (but still high enough to produce eutrophic conditions) until the end of sampling about 15 months after re-flooding. When re-flooding historically drained soils, managers should consider the potential for sediment P release to jeopardize restoration goals and therefore should incorporate longer term monitoring of water quality into restoration plans. Knowledge of sediment P amounts and forms can indicate the potential for P release to overlying water.  相似文献   

6.
Stormwater detention ponds are widely utilized as control structures to manage runoff during storm events. These ponds also represent biogeochemical hotspots, where carbon (C) and nutrients can be processed and buried in sediments. This study quantified C and nutrient [nitrogen (N) and phosphorus (P)] sources and burial rates in 14 stormwater detention ponds representative of typical residential development in coastal South Carolina. Bulk sediment accumulation was directly correlated with catchment impervious surface coverage (R2 = 0.90) with sediment accumulation rates ranging from 0.06 to 0.50 cm y?1. These rates of sediment accumulation and consequent pond volume loss were lower than anticipated based on maintenance guidelines provided by the State. N-alkanes were used as biomarkers of sediment source; the derived terrestrial aquatic ratio (TARHC) index was strongly correlated with sediment accumulation rate (R2 = 0.71) which, in conjunction with high C/N ratios (16–33), suggests that terrestrial biomass drives this sediment accumulation, with relatively minimal contributions from algal derived material. This is counter to expectations that were based on the high algal productivity generally observed in stormwater ponds and previous studies of natural lakes. Sediment C and nutrient concentrations were consistent among ponds, such that differences in burial rates were a simple function of bulk sediment accumulation rate. These burial rates (C: 8.7–161 g m?2 y?1, N: 0.65–6.4 g m?2 y?1, P: 0.238–4.13 g m?2 y?1) were similar to those observed in natural lake systems, but lower than those observed in reservoirs or impoundments. Though individual ponds were small in area (930–41,000 m2), they are regionally abundant and, when mean burial rates are extrapolated to the regional scale (≈ 21,000 ponds), ultimately sequester 2.0 × 109 g C y?1, 9.5 × 107 g N y?1, and 3.7 × 107 g P y?1 in the coastal region of South Carolina alone. Stormwater ponds represent a relatively new but increasingly significant feature of the coastal landscape and, thus, are a key component in understanding how urbanization alters the transport and transformations of C and nutrients between terrestrial uplands and downstream receiving waters.  相似文献   

7.
The pathogenesis of HIV-associated neurocognitive disorder (HAND) is modulated by host genetic susceptibility factors such as Matrix metalloproteinases (MMPs). Promoter polymorphism of MMP-1 and MMP-3 may modify the expression of the gene. Hence, we evaluated the association of MMP-1-16072G/1G and MMP-3-1612 5A/6A polymorphisms with development of HAND and the modulation of pathogenesis of HAND. We enrolled a total of 180 individuals, 50 HIV-infected individuals with HAND, 130 without HAND, and 150 healthy controls. Polymorphism of MMP-1 and MMP-3 were genotyped by PCR-RFLP. MMP-1-1607 2G1G, -16071G/2G-1G/1G genotypes and -1607 1G allele were associated with the development of HAND (OR = 1.64, P = 0.05; OR = 1.45, P = 0.04; OR = 1.69, P = 0.05). MMP-1-16071G1G, MMP-3-16125A5A genotypes increased the risk for the development of HAND (OR = 1.78, P = 0.25; OR = 2.39, P = 0.13). MMP-3-1612 5A5A, -1612 6A/5A-5A/5A genotypes and -1612 5A allele were associated with the reduced risk of HAND (OR = 0.40, P = 0.05; OR = 0.53, P = 0.04; OR = 0.40, P = 0.01). Haplotype 5A1G increased the risk of development of HAND (OR = 1.93, P = 0.05). As observed in advanced HIV disease stage, MMP-1-1607 1G1G genotype enhance the risk for advancement of HIV disease (OR = 1.69, P = 0.89). MMP-3-1612 6A5A genotype showed higher risk for development of HAND in alcohol users (0R = 1.65, P = 0.44). MMP-1 genotype may have an influence on development of HAND whereas MMP3-1612 5A5A genotype may reduce risk for pathogenesis of HAND.  相似文献   

8.
Bhadoria  P.S.  El Dessougi  H.  Liebersbach  H.  Claassen  N. 《Plant and Soil》2004,262(1-2):327-336
Phosphorus acquisition efficiency of maize (Zea mays L.) and groundnut (Arachis hypogaea L.) was investigated in a flowing nutrient solution culture at constant P concentrations of 0.2, 1 and 100 μM. To calculate the P influx and study changes in plant growth and P uptake in relation to plant age, four harvests were taken. Phosphorus uptake kinetics of the roots, i.e. maximum influx, I\max, the Michaelis constant, Km, and the minimum concentration, CLmin (the concentration at which no net uptake occurs) were estimated in a series of short-term experiments, based on the rate of depletion of P from solution over a range of concentrations. At 1 μM P, maize was more P efficient producing up to 90% of its maximum yield as compared to groundnut with only 20% of maximum yield. A 3 times faster P uptake rate was the reason for the maize P efficiency. In contrast for groundnut at 1 μM P, a net efflux was observed at some development stages of this crop indicating a much higher P requirement at the root surface for maximum growth. Maize had a 6 times higher I\max value and a 2 times higher Km value as compared to groundnut. The higher influx of maize was mainly because of the higher I\max. Maize previously grown at low P concentrations had a CLmin of 0.1 μM, while groundnut had values of 0.2 and 0.6 μM. Furthermore groundnut previously grown at 100 μM, was not able to absorb P even at 40 μM. Acclimation to low P concentrations in solution by increasing I\max or decreasing Km was not evident in this study. Differences in P acquisition efficiency between maize and groundnut in solution culture were mainly because of differences in P-uptake kinetics, and to a lesser extent to the size of the root system.  相似文献   

9.
The genetic diversity of 116 barley accessions, representing five Chinese eco-geographic populations, was studied using simple sequence repeat (SSR) markers. The 21 SSR loci revealed 128 alleles with an average of 6.1 alleles per locus. The highest values of proportion of polymorphic loci (P) and gene diversity index (He) were obtained in the Northern (P = 1.00; He = 0.60) and the Yangtze River reaches and Southern populations (P = 1.00; He = 0.59). The lowest values were in the populations of the Yellow River reaches (P = 0.86; He = 0.44). The highest average number of alleles per locus (4.52) and number of unique alleles (7) were found in the Qinghai–Tibet plateau population. Cluster analysis revealed that together with the row type, strong eco-geographic variables influenced the classification. Associations of SSR and eco-geographic values were established for 11 SSR loci. Four to six markers were found to discriminate among geographic groups, which may serve as tools for diagnosis of the eco-geographic populations and provide evidence for the adaptive nature of SSR markers.  相似文献   

10.
Cuet  P.  Atkinson  M. J.  Blanchot  J.  Casareto  B. E.  Cordier  E.  Falter  J.  Frouin  P.  Fujimura  H.  Pierret  C.  Susuki  Y.  Tourrand  C. 《Coral reefs (Online)》2011,30(1):45-55

Productivity, nutrient input, nutrient uptake, and release rates were determined for a coral-dominated reef flat at La Réunion, France, to assess the influence of groundwater nitrogen on carbon and nutrient budgets. Water samples were collected offshore in the ocean, at the reef crest and back reef for nutrients, picoplankton, pH, and total alkalinity. Volume transport of ocean water across the reef flat was measured using both current meters and drogues. Groundwater advected onto the reef flat and mixed with incoming ocean water. Metabolic rates for the reef community were determined to be: gross primary production = 1,000 mmol C m−2 d−1, community respiration = 960 mmol C m−2 d−1, and community calcification = 210 mmol C m−2 d−1. Across the reef flat, silicate behaved conservatively, there was net uptake of phosphate (0.06 mmol P m−2 d−1) and net release of nitrate, ammonia, dissolved and particulate organic nitrogen (total 7.0 mmol N m−2 d−1). Groundwater nitrate contributed 37% of the increase in nitrate plus ammonia. The first-order mass transfer coefficient of phosphate was 3.3 m d−1, and for nitrate plus ammonia, 5.9 m d−1. Gross N and P uptake from estimates of mass transfer and uptake of particles were 0.37 mmol P m−2 d−1 and 7.2 mmol N m−2 d−1, respectively giving an N:P uptake ratio of 20:1. Thus, the elevation of nitrogen across the reef flat maintains a high N:P flux, enhancing algal growth downstream of the transect. We conclude that net community production (40 mmol C m−2 d−1) was sustained by net uptake of phosphate from the ocean and net uptake of new nitrogen from groundwater.

  相似文献   

11.
To determine the effects of sustained swimming on the use and fate of dietary nutrients in gilthead sea bream, a group of fish were forced to undertake moderate and sustained swimming (1.5 BL s?1) for 3 weeks and compared with a control group undertaking voluntary activity. The exercise group showed a significant increase in specific growth rate (C: 1.13 ± 0.05; E: 1.32 ± 0.06 % day?1, P < 0.05) with no significant change in food intake (C: 3.56 ± 0.20; E: 3.84 ± 0.03 % of body weight). The addition of 13C-starch and 15N-protein to a single meal of 1 % ration allowed analysis of the fate of both nutrients in several tissues and in their components, 6 and 24 h after force-feeding. In exercised fish improved redistribution of dietary components increased the use of carbohydrates and lipid as fuels. Gilthead sea bream have a considerable capacity for carbohydrate absorption irrespective of swimming conditions, but in trained fish 13C rose in all liver fractions with no changes in store contents. This implies higher nutrient turnover with exercise. Higher retention of dietary protein (higher 15N uptake into white muscle during the entire post-prandial period) was found under sustained exercise, highlighting the protein-sparing effect. The combined effects of a carbohydrate-rich, low-protein diet plus sustained swimming enhanced amino acid retention and also prevented excessive lipid deposition in gilthead sea bream.  相似文献   

12.
Background

Insulin resistance (IR) in humans is related to hypertension and impaired vasodilation. Insulin administration has been shown to lower blood pressure both in insulin resistant as well as in insulin sensitive individuals. The aim of the study was to investigate the association between insulin sensitivity and alterations in blood pressure in healthy horses before and after a euglycemic-hyperinsulinemic clamp (EHC). A 3-h EHC was performed in 13 healthy horses (11 mares, 2 geldings). Blood samples for measurement of plasma glucose and insulin were collected before the start of the EHC, every 10 min during the EHC and immediately after the EHC. Mean, systolic- and diastolic blood pressure was measured before and during the final 10 min of the EHC using an indirect high-definition oscillometric monitor (HDO, horse model) applied to the middle of the coccygeal artery. Five consecutive measurements were made in each horse and on each occasion. Insulin and glucose data from the EHC were used to calculate the mean rate of glucose disposal per unit of insulin during steady state (M/I ratio). Insulin resistance was defined as a M/I ratio <5 mg/kg/min/mUL (Lindåse et al. in Am J Vet Res 77:300–309, 2016).

Results

Insulin administration decreased systolic, diastolic and mean arterial pressure in all horses. The M/I ratio for all horses was negatively correlated with the decrease in systolic blood pressure (r2 = 0.55, P = 0.004) and mean arterial pressure (r2 = 0.31, P = 0.048) but not diastolic blood pressure (r2 = 0.12, P = 0.26). Eight horses were defined as insulin resistant (IR) and five horses had normal insulin sensitivity. The five horses with normal insulin sensitivity showed a greater decrease in systolic blood pressure (−17.0 ± 7.4 vs. −3.4 ± 4.6 mmHg, P = 0.001) and MAP (19.2 ± 14.7 vs. 6.9 ± 8.7 mmHg, P = 0.04) than IR horses. There was no difference in the decrease in diastolic blood pressure between groups (16 ± 12.8 vs. 8.9 ± 12.1 mmHg, P = 0.17).

Conclusions

This study indicates that there is a relationship between insulin sensitivity and systolic and MAP in horses. However, studies on a larger number of horses are needed to confirm this association.

  相似文献   

13.
The recent implementation of agricultural best management practices (BMPs) and treatment wetlands called stormwater treatment areas (STAs) have reduced phosphorus (P) concentrations and loadings to the Everglades Protection Area (EPA) in Florida (USA). There is a concern that despite reductions in external P loadings, internal loading from the legacy P enrichment of the EPA wetland soils will continue to elevate water column P concentrations, and may impede restoration outcomes. In an effort to explore ways to reduce soil P efflux, we retrieved intact, vegetated (cattail, Typha domingensis) soil monoliths from two P-enriched areas of the EPA and deployed them at a location where they received pre-treated (low P) surface water as ex situ flow-through mesocosms for 21 months with a mid-study 7-week dry down to mimic natural hydroperiod conditions. Two treatments were tested for soils from both sites, using triplicate mesocosms for each treatment. After applying a herbicide (glyphosate) to eliminate the cattail vegetation, iron (Fe as liquid FeCl3) amendments provided no P retention benefits in the organic soils from the two sites, and did not yield significantly (P > 0.05; n = 43) lower flux rates (6.1 and 3.5 mg Pm?2 d?1) than the herbicide/no soil amendment control (3.9 and 2.1 mg Pm?2 d?1), as was expected. A combination of low oxidation–reduction potential, heightened organic matter P mineralization, high pH, and sulfide production acted interactively to enhance Fe and P mobilization in the Fe-amended mesocosms. The herbicide/limerock (CaCO3)-amended soils exhibited significantly lower (P ≤ 0.05; n = 43) P flux (1.3 and 1.1 mg Pm?2 d?1) than the herbicide/no soil amendment control soils, but it remains unknown whether the observed reduction in P efflux (ranging from 48 to 67%) would justify the expense and potential environmental impacts of applying a surficial limerock amendment to large regions of the P-enriched wetlands.  相似文献   

14.
Wastewater from different sources shows great differences in concentrations and ratios of N and P. In order to choose suitable plant species to remove excess N and/or P from polluted waters, it is important to know the performances of these plants under different N and P concentrations. In this study, we investigated the growth and N and P removal rate of three macrophytes, Coix lacryma-jobi, Iris wilsonii, and Arundo donax under six N and P combination treatments. C. lacryma-jobi preferred higher N and P concentrations (16 mg N L?1 and 3.2 mg P L?1), and increasing N supply could increase its P removal rate. I. wilsonii exhibited a growth preference at a combination of moderate N and P concentrations (8 mg N L?1 and 0.8 mg P L?1). A. donax could grow well at all combinations of N and P and had significantly higher relative growth rate and N and P removal rates than the other two species. These results showed A. donax is a promising species to treat various polluted waters and the other two species can be used specifically to treat certain types of wastewater.  相似文献   

15.
The meta-analysis aims to investigate association between two matrix metalloproteinases (MMPs) polymorphisms (MMP-2 ?1306 C/T and MMP-9 ?1562 C/T) and breast cancer risk. Eligible studies were retrieved from relevant databases, based on predefined criteria. Quality assessment was evaluated by Newcastle–Ottawa Scale. Odds ratio (OR) with its 95% confidence interval (CI) was selected as the effect size for the meta-analysis. As a result, 13 studies were included. MMP-2 ?1306 C/T polymorphism was not significantly associated with breast cancer risk under all genetic models (P > 0.05). However, subgroup analysis stratified by ethnicity showed a significant association between MMP-2 ?1306 C/T polymorphism and reduced breast cancer risk in Asian populations under allelic model (OR 0.60, 95% CI 0.39–0.90, P = 0.02) and dominant model (OR 0.55, 95% CI 0.34–0.89, P = 0.02). MMP-9 ?1562 C/T polymorphism was significantly related to increased breast cancer risk under allelic model (OR 1.50, 95% CI 1.06–2.12, P = 0.02), additive model (OR 1.45, 95% CI 1.02–2.05, P = 0.04) and recessive model (OR 1.54, 95% CI 1.13–2.12, OR 0.007). A significant association between MMP-9 ?1562 C/T polymorphism and increased breast cancer risk in Caucasian was detected under most of the genetic models (P < 0.05). MMP-2 ?1306 C/T polymorphism might be significantly associated with reduced breast cancer risk in Asian, while MMP-9 ?1562 C/T might be closely related to increased breast cancer risk, especially in Caucasian.  相似文献   

16.
A baseline study on a temperate, oligotrophic North Patagonian lake (Lake Chapo, Southern Chile) was made prior to the installation of a hydroelectric power station. Throughout one year (September 1986–October 1987) the physical and chemical properties of the lake were investigated monthly from the surface to a depth of 40 m. Lake Chapo is a deep, transparent (Secchi depth: 17–25 m), glacial lake located at 41°?27.5′?S and 72°?30′?W. It has a maximum depth of 298 m, mean depth of 183 m, surface area of 45.3 km2 and water volume of 8.296 km3. The theoretical residence time of the water was 5.5 years. The temperature regime is monomictic with the mixed temperature between 8.1–8.8?°C. Maximum temperature at the surface was 18.7?°C during thermal stratification in summer when the epilimnion had a thickness of about 20 m. The conductivity was low (20.3–23.8 μS cm?1) as was the buffering capacity of a predominantly CO2-carbonate system. The predominant cations were Ca+2¿ Na+¿Mg+2¿K+. The phosphorous and nitrogen contents were very low (soluble reactive ortophosphate: 0–1.5 μg P l?1, total phosphorus: 0.3–4 μg P l?1 and nitrate: 0–35 μg N l?1), which is typical of North Patagonian lakes.  相似文献   

17.
This study examined the association between markers in transforming growth factor alpha (TGFA) and isolated, non-syndromic cleft lip with/without palate (CL/P) using a case–parent trio design, considering parent-of-origin effects. We also tested for gene–environmental interaction with common maternal exposures, and for gene–gene interaction using markers in TGFA and another recognized causal gene, IRF6. CL/P case–parent trios from four populations (76 from Maryland, 146 from Taiwan, 35 from Singapore, and 40 from Korea) were genotyped for 17 single nucleotide polymorphisms (SNPs) in TGFA. The transmission disequilibrium test was used to test individual SNPs, and the parent-of-origin likelihood ratio test (PO-LRT) was used to assess parent-of-origin effects. We also screened for possible gene–environment interaction using PBAT, and tested for gene–gene interaction using conditional logistic regression models. When all trios were combined, four SNPs showed significant excess maternal transmission, two of which gave significant PO-LRT values [rs3821261: P = 0.004 and OR(imprinting) = 4.17; and rs3771475: P = 0.027 and OR(imprinting) = 2.44]. Haplotype analysis of these two SNPS also supported excess maternal transmission. We saw intriguing but suggestive evidence of G × E interaction for several SNPs in TGFA when either individual SNPs or haplotypes of adjacent SNPs were considered. Thus, TGFA appears to influence risk of CL/P through unconventional means with an apparent parent-of-origin effect (excess maternal transmission) and possible interaction with maternal exposures.  相似文献   

18.
Because queens of claustral colony-founding ants raise their first workers without foraging outside the nest, the number of first workers produced depends on the nutrient reserves of the queen when she begins to establish the colony. Although a low mortality rate of queens may be expected because they seal themselves off in the nest chambers, they do face a risk of starvation. Therefore, the queens must allocate nutrients for somatic maintenance and worker production, including the feeding of larvae. However, there are few reports on the nutrient consumption of queens. To clarify the nutrient resource utilization of claustral colony-founding queens, newly mated queens of the Japanese black carpenter ant, Camponotus japonicus (Mayr), were collected just after the nuptial flight and reared in an incubator at 25 °C in the dark. The non-lipid mass and lipid mass of the queens were measured at 0, 10, 20, 30, 40, and 52 days after the nuptial flight. A significant decline in the non-lipid mass was found in the queens after hatching of larvae. In contrast, the lipid mass of the queen decreased soon after the nuptial flight. The results indicate that the somatic maintenance of the founding queens relies exclusively on lipids, while other nutrients, such as protein, may be used for feeding the larvae.  相似文献   

19.
Finishing pigs (n = 320) were used in a 35-day study to determine the effects of ractopamine-HCl (RAC) and supplemental Zinc (Zn) level on loin eye area (LEA) and gene expression. Pens were randomly allotted to the following treatments for the final 35 days on feed: a corn-soybean meal diet (CON), a diet with 10 ppm RAC (RAC+), and RAC diet plus added Zn at 75, 150, or 225 ppm. Sixteen pigs per treatment were randomly selected for collection of serial muscle biopsies and carcass data on day 0, 8, 18, and 32 of the treatment phase. Compared to CON carcasses, RAC+ carcasses had 12.6% larger (P = 0.03) LEA. Carcasses from RAC diets with added Zn had a tendency for increased (quadratic, P < 0.10) LEA compared to the RAC+ carcasses. Compared to RAC+ pigs, relative expression of IGF1 decreased with increasing levels of Zn on day 8 and 18 of treatment, but expression levels were similar on day 32 due to Zn treatments increasing in expression while the RAC+ treatment decreased (Zn quadratic × day quadratic, P = 0.04). A similar trend was detected for the expression of β1-receptor where expression levels in the RAC+ pigs were greater than Zn supplemented pigs on day 8 and 18 of the experiment, but the magnitude of difference between the treatments was reduced on day 32 due to a decrease in expression by RAC+ pigs and an increase in expression by the Zn pigs (Zn quadratic × day quadratic, P = 0.01). The ability of Zn to prolong the expression of these two genes may be responsible for the tendency of Zn to increase LEA in RAC supplemented pigs.  相似文献   

20.
The translocation of phosphorus (P) from terrestrial landscapes to aquatic bodies is of concern due to the impact of elevated P on aquatic system functioning and integrity. Due to their common location in depressions within landscapes, wetlands, including so-called geographically isolated wetlands (GIWs), receive and process entrained P. The ability of depressional wetlands, or GIWs, to sequester P may vary by wetland type or by land use modality. In this study we quantified three measures of P sorption capacities for two common GIW types (i.e., emergent marsh and forested wetlands) in two different land use modalities (i.e., agricultural and least impacted land uses) across 55 sites in Florida, USA. The equilibrium P concentration (EPC0) averaged 6.42 ± 5.18 mg P L?1 (standard deviation reported throughout); and ranged from 0.01–27.18 mg P L?1; there were no differences between GIW type or land use modality, nor interaction effects. Significant differences in phosphorus buffering capacity (PBC) were found between GIW types and land use, but no interaction effects. Forested GIWs [average 306.64 ± 229.63 (mg P kg?1) (µg P L?1)?1], and GIWs in agricultural settings [average 269.95 ± 236.87 (mg P kg?1) (µg P L?1)?1] had the highest PBC values. The maximum sorption capacity (Smax) was found to only differ by type, with forested wetlands (1274.5 ± 1315.7 mg P kg?1) having over three times the capacity of emergent GIWs (417.5 ± 534.6 mg P kg?1). Classification trees suggested GIW soil parameters of bulk density, organic content, and concentrations of total P, H2O-extractable P, and HCl-extractable P were important to classifying GIW P-sorption metrics. We conclude that GIWs have high potential to retain P, but that the entrained P may be remobilized to the wetland water column depending on storm and groundwater input P concentrations. The relative hydrologic dis-connectivity of GIWs from other aquatic systems may provide sufficient retention time to retain elevated P within these systems, thereby providing an ecosystem service to downstream waters.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号