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391.
Miki D Ochi H Hayes CN Abe H Yoshima T Aikata H Ikeda K Kumada H Toyota J Morizono T Tsunoda T Kubo M Nakamura Y Kamatani N Chayama K 《Nature genetics》2011,43(8):797-800
Chronic viral hepatitis is the most important risk factor for progression to hepatocellular carcinoma (HCC). To identify genetic risk factors for progression to HCC in individuals with chronic hepatitis C virus (HCV), we analyzed 467,538 SNPs in 212 Japanese individuals with chronic HCV with HCC and 765 individuals with chronic HCV without HCC. We identified one intronic SNP in the DEPDC5 locus on chromosome 22 associated with HCC risk and confirmed the association using an independent case-control population (710 cases and 1,625 controls). The association was highly significant when we analyzed the stages separately as well as together (rs1012068, P(combined) = 1.27 × 10(-13), odds ratio = 1.75). The significance level of the association further increased after adjustment for gender, age and platelet count (P = 1.35 × 10(-14), odds ratio = 1.96). Our findings suggest that common variants within the DEPDC5 locus affect susceptibility to HCC in Japanese individuals with chronic HCV infection. 相似文献
392.
393.
Dense genotyping identifies and localizes multiple common and rare variant association signals in celiac disease 总被引:1,自引:0,他引:1
Trynka G Hunt KA Bockett NA Romanos J Mistry V Szperl A Bakker SF Bardella MT Bhaw-Rosun L Castillejo G de la Concha EG de Almeida RC Dias KR van Diemen CC Dubois PC Duerr RH Edkins S Franke L Fransen K Gutierrez J Heap GA Hrdlickova B Hunt S Izurieta LP Izzo V Joosten LA Langford C Mazzilli MC Mein CA Midah V Mitrovic M Mora B Morelli M Nutland S Núñez C Onengut-Gumuscu S Pearce K Platteel M Polanco I Potter S Ribes-Koninckx C Ricaño-Ponce I Rich SS Rybak A Santiago JL Senapati S Sood A 《Nature genetics》2011,43(12):1193-1201
Using variants from the 1000 Genomes Project pilot European CEU dataset and data from additional resequencing studies, we densely genotyped 183 non-HLA risk loci previously associated with immune-mediated diseases in 12,041 individuals with celiac disease (cases) and 12,228 controls. We identified 13 new celiac disease risk loci reaching genome-wide significance, bringing the number of known loci (including the HLA locus) to 40. We found multiple independent association signals at over one-third of these loci, a finding that is attributable to a combination of common, low-frequency and rare genetic variants. Compared to previously available data such as those from HapMap3, our dense genotyping in a large sample collection provided a higher resolution of the pattern of linkage disequilibrium and suggested localization of many signals to finer scale regions. In particular, 29 of the 54 fine-mapped signals seemed to be localized to single genes and, in some instances, to gene regulatory elements. Altogether, we define the complex genetic architecture of the risk regions of and refine the risk signals for celiac disease, providing the next step toward uncovering the causal mechanisms of the disease. 相似文献
394.
Greasewood ( Sarcobatus ) is a succulent-leaved, halophytic shrub of North American origin. The genus comprises 2 species: Sarcobatus baileyi and Sarcobatus vermiculatus. Sarcobatus vermiculatus is common throughout much of western North America, but S. baileyi is much more limited in distribution and was previously thought to be endemic to Nevada. Here we document and describe a S. baileyi population in eastern California, comparing its morphology and ecology to an adjacent S. vermiculatus population. Morphologically, S. baileyi is smaller in stature but produces larger seeds; however, fewer S. baileyi seeds germinated and survived a 20-day laboratory incubation compared to seeds of S. vermiculatus. Sarcobatus baileyi has higher leaf Na concentrations and operates at much lower plant water potentials than S. vermiculatus under field conditions; however, no significant differences were observed between the 2 species in long-term water-use efficiency as measured by leaf δ13C. Leaf Na concentrations were very low in both species. Overall, these species differ greatly in a number of traits that are consistent with the upland, nonphreatophytic character of S. baileyi, which is in stark contrast to the phreatophytic character of S. vermiculatus. Both species, however, are very salt tolerant and have low leaf N concentrations, indicating the low nutrient availability and the potentially high salinity of their extreme habitats. Further investigation of comparable desert ridge environments should be conducted to determine the extent of S. baileyi in eastern California, and common garden comparisons of the 2 species should be conducted to compare their ecophysiological traits. El ";greasewood” ( Sarcobatus ) es un arbusto halofítico de origen norteamericano con hojas suculentas. El género consta de dos especies: Sarcobatus baileyi y Sarcobatus vermiculatus. Aunque S. vermiculatus es común en gran parte del oeste de Norteamerica, S. baileyi tiene una distribución mucho más limitada. Se pensaba anteriormente que S. baileyi era endémico a Nevada, pero aquí documentamos y describimos una población en el este de California, comparando su morfología y ecología con las de una población adyacente de S. vermiculatus. Morfológicamente, S. baileyi es más pequeña de altura, pero produce semillas más grandes. Sin embargo, menos semillas de S. baileyi germinaron y sobrevivieron a una incubación en laboratorio de 20 días, comparado con S. vermiculatus. Sarcobatus baileyi opera con potenciales de agua mucho más bajos que los de S. vermiculatus en condiciones de campo y tiene mayores concentraciones de Na en sus hojas. No obstante, no se observaron diferencias significativas en la eficiencia del uso de agua a largo plazo, medida en términos de δ13C entre las 2 especies. Las concentraciones de N en las hojas fueron muy bajas en ambas especies. En general, estas especies difieren mucho en varios rasgos que son consistentes con el carácter no freatofítico de S. baileyi de tierras altas, el cual contrasta claramente con el carácter freatofítico de S. vermiculatus. Ambas especies, sin embargo, son bastante tolerantes a la sal y tienen concentraciones bajas de N en hojas, lo cual indica la baja disponibilidad de nutrientes y la potencial alta salinidad en sus hábitats extremos. Investigaciones adicionales en ambientes comparables de bordes desérticos deberán llevarse a cabo para determinar la extensión S. baileyi en el este de California, además de comparaciones de las dos especies en jardín para comparar sus rasgos ecofisiológicos. 相似文献
395.
Timothy D. Hatten Norm Merz James B. Ding Johnson Chris Looney Travis Ulrich Scott Soults Roland Capilo Dwight Bergerone Paul Anders Philip Tanimoto Bahman Shafii 《西北部美国博物学家》2011,70(4)
The parasitic wasp Mymaromella pala Huber and Gibson (Hymenoptera: Mymarommatidae) was collected at 4 sites within a canyon reach of the Kootenai River in Lincoln County, Montana. This minute species has only recently been described, but it appears to have a large distribution throughout the United States and to be associated with upland and riparian forests. La avispa parasitaria Mymaromella pala Huber y Gibson (Hymenoptera: Mymarommatidae) se recolectó en cuatro sitios a lo largo de un cañón del Río Kootenai en Lincoln Co., MT. Hace poco que se describió esta especie diminuta, pero parece tener una distribución extensa en los EE.UU. y estar asociada con bosques altos y ribereños. 相似文献
396.
Observations of changes in population density of native White River springfish ( Crenichthys baileyi ) in Pahranagat Valley led to the following hypothesis: introduced convict cichlids ( Cichlasoma nigrofasciatum ) cause reduced growth and recruitment; cover reduces the magnitude of the effect. The hypothesis was tested by establishing sympatric and allopatric groups of the two species in experimental aquaria with and without cover. Change in volume (= mass) and length of the two species over a three-month period in spring 1986 and 1987 was measured and analyzed using 2 × 2 factorial analyses. Convict cichlids caused reduced growth and eliminated recruitment of springfish under the experimental conditions. Cover did not influence growth but positively affected recruitment of springfish in allopatry. It is likely that a portion of the reduced springfish population densities in nature can be attributed to adverse effects from introduced cichlids. 相似文献
397.
Restoring coal mined land to pre-mining shrub cover, density, height, community composition, and diversity to renew wildlife habitat quality is a priority for reclamation specialists. Long-term shrub reestablishment success on reclaimed mined land in Wyoming and suitability of these lands for wildlife habitat are unknown. Fourteen reclaimed study sites, 10 yr old or older, were selected on 8 mines in Wyoming to evaluate shrub reestablishment and wildlife habitat value for antelope ( Antilocapra americana ) and sage grouse ( Centrocercus urophasianus ). Five sites were categorized as fourwing saltbush ( Atriplex canescens ) sites and 9 as fourwing saltbush/big sagebrush ( A. canescens/Artemisia tridentata spp. wyomingensis ) sites. Published data describing antelope and sage grouse-preferred habitat requirements in sagebrush-grassland steppe ecosystems were used to evaluate shrub community value of sampled sites for wildlife habitat. Mean shrub canopy cover, density, and height for fourwing saltbush sites were 5.8%, 0.23 m -2 , and 41.6 cm, respectively, compared to 5.6%, 0.61 m -2 , and 31.1 cm for fourwing saltbush/big sagebrush sites. Two fourwing saltbush and 4 fourwing saltbush/big sagebrush sites provided sufficient cover for antelope, while 2 fourwing saltbush and 4 fourwing saltbush/big sagebrush sites were adequate for sage grouse. Only 1 fourwing saltbush/big sagebrush site provided high enough shrub densities for sage grouse. One fourwing saltbush and 7 fourwing saltbush/big sagebrush sites provided ample shrub heights for antelope, while 1 fourwing saltbush and 8 fourwing saltbush/big sagebrush sites were sufficient for sage grouse. One fourwing saltbush and 1 fourwing saltbush/big sagebrush site provided enough grass, forb, and shrub composition for antelope, while no site in either reclamation type was satisfactory for sage grouse. Shrub diversity was 3 times higher for fourwing saltbush/big sagebrush sites (0.984) than for fourwing saltbush sites (0.328). Individually, sites seeded with multiple shrub species had higher canopy cover, density, and diversity compared with single-species shrub seedings. Achieving premining shrub cover, density, height, community composition, and diversity within existing bond-release time frames is unrealistic, considering that some native shrublands require 30-60 yr to reach maturity. 相似文献
398.
The demography of black sagebrush ( Artemisia nova Nelson) was investigated in the Buckskin Mountains of western Nevada to determine patterns of stand renewal in sagebrush communities currently free from wildfires. Biomass sampling was conducted to develop growth classes that reflected apparent age of the shrubs. The density of black sagebrush plants was twice that of basin big sagebrush ( A. tridentata ssp. tridentata Nutt.) in adjacent communities on contrasting soils (2.2 versus 1.1 plants per m 2 ). Black sagebrush accumulated only 75% as much woody biomass as big sagebrush. Regression equations were developed and tested for predicting total woody biomass, current annual growth (CAG), and leaf weight of black sagebrush plants. Apparent age classes were developed both for the black sagebrush plants and the sub-canopy mounds on which they grew. Discriminant analysis was used to test this classification system. Plant succession, apparently controlled by nitrate content of the surface soil, appeared to eliminate the successful establishment of black sagebrush seedlings on the mounds. After the shrubs die, the mounds eventually deflate. We propose that mounds reform around shrub seedlings, but because seedling establishment is so rare in these communities, this could not be verified. 相似文献
399.
The genus Capnia in North America is reviewed and compared to other genera in the family. The genus is divided into 10 species groups. A key to the 51 species of Capnia in North America is given along with a listing of type localities, type repositories, diagnoses, and distributions. New illustrations of structures bearing characters important for identification and classification are presented. An annotation of the list of Capnia of North America given by Stark, Szczytko, and Baumann (1986) reflecting current generic placement of species is produced. From this list Capnia bakeri and sugluka are moved to Mesocapnia . Capnia barbata Frison is placed in synonymy under Capnia decepta . The movement of cygna (synonym of venosa ), elevata, fibula, manitoba, venosa , and wanica to Capnura (Nelson and Baumann, 1987b) is noted. Capnia disala and ensicala are placed in Paracapnia . 相似文献
400.
The Black Hills of South Dakota and Wyoming are an insular mountain range completely surrounded by the Great Plains. The stonefly (Plecoptera) fauna of the Black Hills was surveyed and zoogeographic affinities examined. Twenty-seven species representing 22 genera and 6 families were found. Fifteen new state records for South Dakota and 2 for Wyoming are presented. Two species are removed from the South Dakota list. An analysis of the North American distribution of each species showed a strong relationship between the Black Hills and the Rocky Mountains, with much weaker relationships between the Black Hills and eastern and northern regions. Results of a logistic regression analysis comparing factors contributing to long-distance dispersal ability against presence/absence in the Black Hills were inconclusive. However, other evidence suggests that the Black Hills fauna is a result of expansion and subsequent vicariance of stonefly populations during Pleistocene climatic oscillations. 相似文献