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101.
Thaunat O Granja AG Barral P Filby A Montaner B Collinson L Martinez-Martin N Harwood NE Bruckbauer A Batista FD 《Science (New York, N.Y.)》2012,335(6067):475-479
During the activation of humoral immune responses, B cells acquire antigen for subsequent presentation to cognate T cells. Here we show that after mouse B cells accumulate antigen, it is maintained in a polarized distribution for extended periods in vivo. Using high-throughput imaging flow cytometry, we observed that this polarization is preserved during B cell division, promoting asymmetric antigen segregation among progeny. Antigen inheritance correlates with the ability of progeny to activate T cells: Daughter cells receiving larger antigen stores exhibit a prolonged capacity to present antigen, which renders them more effective in competing for T cell help. The generation of progeny with differential capacities for antigen presentation may have implications for somatic hypermutation and class switching during affinity maturation and as B cells commit to effector cell fates. 相似文献
102.
A yearling Irish Cob stallion was presented to De Morette Equine clinic for severe acute abdominal pain, nonresponsive to analgesics and sedatives. Rectal palpation and a limited transabdominal ultrasonographic examination led to the presumptive diagnosis of a strangulated obstruction of the small intestine. The painful behaviour of the pony did not allow conservative treatment and surgical exploration was denied by the owners for financial considerations. On necropsy, a large cystic mature teratoma was adhered to the ventral body wall, the mesenteric root, omentum and intestines. Teratomas are rare in man and animals, and an extragonadal intraperitoneal location has not previously been reported in the equine species. 相似文献
103.
Mozzaquatro FD Verstegen JP Douglas RH Troedsson MH Delacorte FD Silva CA Rubin MI 《Reproduction in domestic animals》2012,47(2):288-292
Ultrasound‐guided follicular aspiration was performed in 26 Criollo crossbred mares, followed by the evaluation of ultrasonographic images of the Corpus luteum (CL) that was formed after puncture of follicles of different diameters (Group 25–29 mm; Group 30–35 mm and Group >35 mm). Serum progesterone (P4) concentrations were measured to determine CL function. The size of the CL was measured and the CL was classified based on the following echoscore: 1– anechoic tissue; 2– poorly defined luteal structure with low echogenicity; 3– echogenicity analogous to a luteal structure. The proportion of aspirated follicles that formed a functional CL (based on P4 concentration) 8 days after aspiration was 57.1% (4/7; CL size 25–29 mm), 75.0% (6/8; CL size 30–35 mm) and 72.7% (8/11; CL size >35 mm), respectively (p > 0.05). The echographic scores of aspirated follicles (indicating the presence or absence of a CL) were consistent with serum P4 concentrations (p < 0.0001). Of 26 aspirations, 18 resulted in luteal function confirmed by increased progesterone concentrations ([P4] > 1.0 ng/ml); 17 of these mares (94.4%) had an echoscore (2–3) compatible with luteinization (p = 0.0372). Eight days after aspiration, serum [P4] > 2.0 ng/ml was associated with high (p = 0.0056) CL echoscore (3) in 15 of 17 mares (88.2%). The echoscore used in this study was valuable as a screening test to detect the presence of a functional CL after aspiration. An echoscore of 3 served as a practical and efficient method to confirm luteinization. 相似文献
104.
Wright D Rubin C Schutz K Kerje S Kindmark A Brandström H Andersson L Pizzari T Jensen P 《Reproduction in domestic animals》2012,47(Z1):31-36
Onset of sexual maturation is a trait of extreme importance both evolutionarily and economically. Unsurprisingly therefore, domestication has acted to reduce the time to sexual maturation in a variety of animals, including the chicken. In comparison with wild progenitor chickens [the Red Junglefowl (RJF)], domestic layer hens attain maturity approximately 20% earlier. In addition, domestic layers also possess larger combs (a sexual ornament), produce more eggs and have denser bones. A large quantitative trait loci (QTL) analysis (n=377) was performed using an F(2) intercross between a White Leghorn layer breed and a RJF population, with onset of sexual maturity measured and mapped to three separate loci. This cross has already been analysed for comb mass, egg production and bone allocation. Onset of sexual maturity significantly correlated with comb mass, whilst the genetic architecture for sexual maturity and comb mass overlapped at all three loci. For two of these loci, the QTL for sexual maturity and comb mass were statistically indistinguishable from pleiotropy, suggesting that the alleles that increase comb mass also decrease onset of sexual maturity. 相似文献
105.
Friardi Ismed Françoise Lohézic-Le Dévéhat Olivier Delalande Sourisak Sinbandhit Amri Bakhtiar Joël Boustie 《Fitoterapia》2012
The diphenyl ether, lobarin (1) (syn. lobariol carboxylic acid) related to lobaric acid was isolated for the first time as a natural product along with five known compounds from Stereocaulon halei, a fruticose lichen collected in Indonesia. The structure of lobarin was elucidated by spectroscopic data analysis and its most stable conformers were determined by molecular mechanic dynamic calculations. A marked superoxide anion scavenging was found for compound 1 while no cytotoxicity on the B16 murine melanoma and HaCaT human keratinocyte cell lines was observed. 相似文献
106.
Olivier Taugourdeau Jean Dauzat Sébastien Griffon Sylvie Sabatier Yves Caraglio Daniel Barthélémy 《Annals of Forest Science》2012,69(6):713-721
Context
Understanding the effects of exogenous factors on tree development is of major importance in the current context of global change. Assessing the structure development of trees is difficult given that they are large and complex organisms with lifespan of several decades.Aims
We used a retrospective analysis to derive the ontogenetic trends in silver fir development and assess the effects of climate or light environment on tree architecture.Methods
Thanks to the identification of relevant growth markers (bud cataphylls and pseudo-whorl branches), a retrospective analysis allowed to record annual shoot extension and to date them on silver firs of various sizes under different environmental conditions.Results
The length of successive annual shoots located on different axes clearly show gradual trends related to the physiological age of meristems. Within- and between-tree variations are noted due to the plasticity of development and growth induced by light environment and climate.Conclusion
Retrospective analysis is an efficient method for getting information on the history of trees architecture and subsequently to relate it to environmental factors. 相似文献107.
108.
109.
Joseph Dahlen P. David Jones R. Daniel Seale Rubin Shmulsky 《Wood Science and Technology》2013,47(6):1153-1165
Visually graded southern pine (SP) has wide variability within grade. For 2 × 4 lumber, this variability has increased because it is harvested from both natural forests and plantation forests where trees contain high percentages of juvenile wood. To investigate resource variability, six kiln-dried No. 2 2 × 4 SP packages were acquired from six mills. From each package, 124 samples were destructively tested in bending. Mean modulus of elasticity (MOE15) ranged from 9.2 to 13.1 GPa, and three mills did not meet the design values (11.0 GPa). Bending strength (F b) ranged from 7.6 to 11.9 MPa, and four mills did not meet the design values (10.3 MPa). Analysis of variance of MOE15 and F b showed significant differences between mills. MOE15 explained from 33 to 51 % of the variability in F b. These data suggest that variation between mills is high and destructive testing is critical for more accurate characterization of lumber properties. 相似文献
110.
Anne Praud Olivier Gimenez Gina Zanella Nathalie Pozzi Valérie Antras Laurence Meyer Bruno Garin-Bastuji 《Tropical animal health and production》2013,45(4):931-933
Porcine brucellosis due to Brucella suis biovar 1 raises important issues for pig breeders in French Polynesia. In this region, the disease is enzootic, spreads silently and engenders economic losses in infected farms as well as sporadic human cases. While serological tests are essential in surveillance and control programmes of animal diseases, to date none of the available tests have been shown to be reliable enough to be used as a gold standard in routine individual diagnosis of porcine brucellosis. Few studies about the estimation of the sensitivity and the specificity of porcine brucellosis screening tests have been published, none of them dealing with French Polynesia. The studied population included 1,595 pigs from French Polynesia. Five tests were evaluated: Rose Bengal test, fluorescence polarisation assay, indirect ELISA, and two competitive ELISAs (C-ELISA). The sensitivity and the specificity of each test were estimated. C-ELISA2 was the most sensitive test (Se C-ELISA2?=?0.954 [0.889; 0.992] 95 % credibility interval (CrI)) while both C-ELISA and Rose Bengal test (RBT) were the most specific ones (Sp C-ELISA1?=?0.856 [0.806; 0.915] 95 % CrI; Sp C-ELISA2?=?0.849 [0.817; 0.879] 95 % CrI; Sp RBT?=?0.853 [0.812; 0.898] 95 % CrI). 相似文献