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91.
The separate contributions of different vectors to net seed dispersal curves of diplochorous systems have rarely been characterised. In Australia, myrmecochory is a common seed dispersal syndrome and in the majority of such systems, seeds are initially dispersed ballistically. We measured ballistic and myrmecochorous seed dispersal distances in relation to canopies of Adriana quadripartita (Euphorbiaceae) and used a simulation model to estimate the net dispersal curve. We also compared seed removal rates and ant abundances under, and outside, plant canopies to examine how foraging patterns by ants may affect net dispersal.Overall ant abundance did not show a significant numerical response to seedfall; however, the abundance of the main seed dispersing ant, Rhytidoponera ‘metallica’ did. Despite this, seed removal rates did not differ significantly between canopy and open locations. Rhytidoponera ‘metallica’ account for 93% of observed seed dispersal events. On average, the ants dispersed seeds 1.54 m and in doing so, moved seed a mean radial distance of 0.76 m away from canopy edges. This contribution to net dispersal distance by ants is considerable since ballistic dispersal moved seeds a median distance of 7.5 cm. Our simulation model indicated that the combination of ballistic and ant seed dispersal is expected to result in seeds being transported a median net radial dispersal distance of 1.05 m from the canopy edge.Thus in this system, an important function of diplochory may simply be to move a higher proportion of seeds from under the canopy of parent plants than is possible by ballistic dispersal alone. This ‘dispersal-for-distance’ may result in reduced parent–offspring competition or may increase the probability that seeds reach rare safe sites for germination and recruitment. 相似文献
92.
93.
Fleur E van de Geijn Manfred Wuhrer Maurice HJ Selman Sten P Willemsen Ya?l A de Man André M Deelder Johanna MW Hazes Radboud JEM Dolhain 《Arthritis research & therapy》2009,11(6):R193
Introduction
Improvement of rheumatoid arthritis (RA) during pregnancy has been causatively associated with increased galactosylation of immunoglobulin G (IgG) N-glycans. Since previous studies were small, did not include the postpartum flare and did not study sialylation, these issues were addressed in the present study. 相似文献94.
Paul M Kulesa Jessica M Teddy Miranda Smith Richard Alexander Cameron HJ Cooper Rusty Lansford Rebecca McLennan 《BMC developmental biology》2010,10(1):101
Background
Tracing cell dynamics in the embryo becomes tremendously difficult when cell trajectories cross in space and time and tissue density obscure individual cell borders. Here, we used the chick neural crest (NC) as a model to test multicolor cell labeling and multispectral confocal imaging strategies to overcome these roadblocks. 相似文献95.
96.
Individual specialisation can lead to the exploitation of different trophic and habitat resources and the production of morphological
variability within a population. Although the ecological causes of this phenomenon are relatively well known, its consequences
on individual fitness are less recognised. We have investigated the extent of individual specialisation in resource use and
trophic morphology and its fitness consequences through a combination of tagging–recapture, stable isotope analyses and telemetry.
The European eel (Anguilla anguilla) was the model species as it displays significant variability in head shape. Independent to their body length, individuals
with broader heads displayed a significantly higher trophic position (δ15N) than individuals with narrower heads. This corresponded with a significantly higher proportion of prey fish in their diet
compared with invertebrates and was associated with the use of a habitat niche located further from the river bank. The European
eel therefore provides a rare empirical example of individual specialisation in resource use and trophic morphology in a natural
population occurring at a very small spatial scale. Individuals with intermediate head morphology displayed lower body condition
(a proxy of fitness) than individuals with extreme head morphology (i.e. narrower and broader headed individuals), demonstrating
the existence of disruptive selection associated with individual specialisation. 相似文献
97.
Sadeyen JR Trotereau J Velge P Marly J Beaumont C Barrow PA Bumstead N Lalmanach AC 《Microbes and infection / Institut Pasteur》2004,6(14):1278-1286
Asymptomatic Salmonella enterica serovar Enteritidis carrier state in poultry has serious consequences on food safety and public health due to the risks of food poisoning following consumption of contaminated products. An understanding the mechanisms of persistence of Salmonella in the digestive tract of chicken can be achieved by a better knowledge of the defects in the control of infection in susceptible versus resistant animals. The gene expression of innate immune response factors including anti-microbial molecules, inflammatory and anti-infectious cytokines was studied in the caecal lymphoid tissue associated with the carrier state. Expression levels of these genes were assessed by real-time PCR and were compared in two inbred lines of chickens differing in resistance to the carrier state following oral inoculation of S. enterica serovar Enteritidis at 1 week of age. No correlation was observed between resistance/susceptibility to caecal carrier state and level of interleukin (IL)-1beta, IL-8, IL-18, inducible NO synthase (iNOS) and natural resistance associated macrophage protein 1 (NRAMP1). A high baseline level of defensin gene expression was recorded in young animals from the susceptible line. In contrast, a significantly low expression of interferon-gamma (IFN-gamma) gene was observed in these susceptible infected animals in comparison to resistant ones and healthy counterparts. IFN-gamma expression level represents a valuable indication of immunodeficiency associated with persistence of Salmonella in the chicken digestive tract, and IFN-gamma thus represents a factor to consider in the development of prophylactic measures for the reduction of Salmonella carrier state. 相似文献
98.
Laure Frésard Sophie Leroux Bertrand Servin David Gourichon Patrice Dehais Magali San Cristobal Nathalie Marsaud Florence Vignoles Bertrand Bed'hom Jean-Luc Coville Farhad Hormozdiari Catherine Beaumont Tatiana Zerjal Alain Vignal Mireille Morisson Sandrine Lagarrigue Frédérique Pitel 《Nucleic acids research》2014,42(6):3768-3782
99.
Background
The accuracy of genomic prediction depends largely on the number of animals with phenotypes and genotypes. In some industries, such as sheep and beef cattle, data are often available from a mixture of breeds, multiple strains within a breed or from crossbred animals. The objective of this study was to compare the accuracy of genomic prediction for several economically important traits in sheep when using data from purebreds, crossbreds or a combination of those in a reference population.Methods
The reference populations were purebred Merinos, crossbreds of Border Leicester (BL), Poll Dorset (PD) or White Suffolk (WS) with Merinos and combinations of purebred and crossbred animals. Genomic breeding values (GBV) were calculated based on genomic best linear unbiased prediction (GBLUP), using a genomic relationship matrix calculated based on 48 599 Ovine SNP (single nucleotide polymorphisms) genotypes. The accuracy of GBV was assessed in a group of purebred industry sires based on the correlation coefficient between GBV and accurate estimated breeding values based on progeny records.Results
The accuracy of GBV for Merino sires increased with a larger purebred Merino reference population, but decreased when a large purebred Merino reference population was augmented with records from crossbred animals. The GBV accuracy for BL, PD and WS breeds based on crossbred data was the same or tended to decrease when more purebred Merinos were added to the crossbred reference population. The prediction accuracy for a particular breed was close to zero when the reference population did not contain any haplotypes of the target breed, except for some low accuracies that were obtained when predicting PD from WS and vice versa.Conclusions
This study demonstrates that crossbred animals can be used for genomic prediction of purebred animals using 50 k SNP marker density and GBLUP, but crossbred data provided lower accuracy than purebred data. Including data from distant breeds in a reference population had a neutral to slightly negative effect on the accuracy of genomic prediction. Accounting for differences in marker allele frequencies between breeds had only a small effect on the accuracy of genomic prediction from crossbred or combined crossbred and purebred reference populations. 相似文献100.
Thanh-Son Tran Agnès Narcy Bernard Carré Irène Gabriel Nicole Rideau Hélène Gilbert Olivier Demeure Bertrand Bed’Hom Céline Chantry-Darmon Marie-Yvonne Boscher Denis Bastianelli Nadine Sellier Marie Chabault Fanny Calenge Elisabeth Le Bihan-Duval Catherine Beaumont Sandrine Mignon-Grasteau 《遗传、选种与进化》2014,46(1):25