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排序方式: 共有282条查询结果,搜索用时 15 毫秒
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CA Kalva-Filho EZ Campos VL Andrade ASR Silva AM Zagatto MCS Lima M Papoti 《Biology of sport / Institute of Sport》2015,32(4):333-337
The aims of the present study were to investigate the relationship of aerobic and anaerobic parameters with 400 m performance, and establish which variable better explains long distance performance in swimming. Twenty-two swimmers (19.1±1.5 years, height 173.9±10.0 cm, body mass 71.2±10.2 kg; 76.6±5.3% of 400 m world record) underwent a lactate minimum test to determine lactate minimum speed (LMS) (i.e., aerobic capacity index). Moreover, the swimmers performed a 400 m maximal effort to determine mean speed (S400m), peak oxygen uptake () and total anaerobic contribution (CANA). The CANA was assumed as the sum of alactic and lactic contributions. Physiological parameters of 400 m were determined using the backward extrapolation technique ( and alactic contributions of CANA) and blood lactate concentration analysis (lactic anaerobic contributions of CANA). The Pearson correlation test and backward multiple regression analysis were used to verify the possible correlations between the physiological indices (predictor factors) and S400m (independent variable) (p < 0.05). Values are presented as mean ± standard deviation. Significant correlations were observed between S400m (1.4±0.1 m·s-1) and LMS (1.3±0.1 m·s-1; r = 0.80), (4.5±3.9 L·min-1; r = 0.72) and CANA (4.7±1.5 L·O2; r= 0.44). The best model constructed using multiple regression analysis demonstrated that LMS and explained 85% of the 400 m performance variance. When backward multiple regression analysis was performed, CANA lost significance. Thus, the results demonstrated that both aerobic parameters (capacity and power) can be used to predict 400 m swimming performance. 相似文献
3.
Isolated microspore culture techniques and recent progress for haploid and doubled haploid plant production 总被引:2,自引:0,他引:2
An isolated microspore culture provides an excellent system for the study of microspore induction and embryogenesis, provides
a platform for an ever-increasing array of molecular studies, and can produce doubled haploid (DH) plants, which are used
to accelerate plant-breeding programs. Moreover, isolated microspore cultures have several advantages over anther culture,
wherein presence of the anther walls can lead to the development of diploid, somatic calli and plants. Although protocols
for isolated microspore culture vary from laboratory to laboratory, the basic steps of growing donor plants, harvesting floral
organs, isolating microspores, culturing and inducing microspores, regenerating embryos, and doubling the chromosomes, remain
the same. Over the past few years, a large proportion of the research reports on isolated microspore culture have focused
on cereal and Brassica species. For some of these species, isolated microspore culture protocols are well established and routinely used in laboratories
around the world for developing new varieties, as well as for basic research in areas such as genomics, gene expression, and
genetic mapping. Although these species are considered highly responsive to microspore culture, improvements in efficiency
are still being made. However, with many species, isolated microspore culture is simply not yet efficient enough at producing
DH plants to be cost-effective for breeding programs. There has been a recent resurgence of haploidy research with response
being reported in some species once considered recalcitrant. Future research programs aimed at elucidating pathways involved
in microspore induction and embryogenesis will be of benefit, as will novel approaches to improve the efficiency of microspore
culture for DH production. With many species, anther culture has proven to be more effective than isolated microspore culture,
necessitating more research to clarify the contribution of the anther wall to embryogenesis. The development of molecular
markers for use in determining the gametic origin of regenerated plants, irrespective of their ploidy, would also be beneficial.
In this review, we aim to provide an overview of the basic isolated microspore culture protocol with an emphasis on recent
progress in several crop species. 相似文献
4.
A. M. R. Ferrie T. D. Bethune G. C. Arganosa D. Waterer 《Plant Cell, Tissue and Organ Culture》2011,104(3):407-413
The Apiaceae family includes vegetables, as well as herb and spice crops. Compared to major crops, there have been few breeding or genetic
improvement programs for any of the Apiaceae, especially the herb and spice species. Haploidy technology can be used to develop uniform, true-breeding lines, as well
as to accelerate breeding programs. Field trials of dill (Anethum graveolens L.), caraway (Carum carvi L.), and fennel (Foeniculum vulgare Mill.) doubled haploid (DH) lines were conducted over 2–5 cropping seasons. Several of the DH dill lines had desirable agronomic
characteristics such as short uniform stature along with early maturity that would be useful for crop improvement. Seed yields
and the essential oil content of the seed harvested from the best performing DH dill lines were either equal to or higher
than the parental line. A DH annual caraway line was identified that produced higher seed yields than the industry standard.
The main constituents of the essential oil for the DH lines of both dill and caraway were similar to the parental lines. Fennel
DH lines exhibited differences in height but were too late in maturity for seed production under prairie conditions. The results
indicate that not only were we able to generate DH lines that could be used in a crop improvement program, but we developed
DH lines that could be used directly as cultivars as these lines performed better than the industry standard (parental line). 相似文献
5.
Jan AM van Laar Jasper H Kappen Paul LA van Daele P Martin van Hagen 《Arthritis research & therapy》2009,11(2):109-3
Behçet's disease is a complex vasculitis of unknown etiology. Abundant neutrophils suggest the involvement of innate immunity. Cytokines are skewed to the T-helper-1 pattern. Few sterile organs are easily accessible for analysis in Behçet's disease. Cañete and coworkers identify inflamed joints as a feasible model and suggest the involvement of innate immunity in Behçet's disease. 相似文献
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7.
MICHEL ROUX NADIA AMÉZIANE MARC ELEAUME 《Zoological Journal of the Linnean Society》2009,155(1):22-39
The main characters of the stalked crinoids of the family Pentacrinitidae attributed to the genus Teliocrinus are re‐evaluated from a quantitative study of phenotype variation, new observations on arm and stalk articulations, and observation of ontogenetic trends. All of the specimens collected in the northern Indian Ocean belong to the same species, i.e. Teliocrinus springeri (Clark, 1909). However, two phenotypes living at different depths remain valid as subspecies: Teliocrinus springeri springeri (Clark, 1909) and Teliocrinus springeri liliaceus (Clark, 1909). Teliocrinus shares several ontogenetic trends with Endoxocrinus, especially in nonfunctional brachial articulations and stalk symplexies. Its assignment to the Diplocrininae is confirmed. A discussion of its affinities with pentacrinid fossil genera in which the crown is well preserved suggests that Diplocrininae could have first appeared during the Lower Cretaceous. A shortening of brachitaxes and a paedomorphic trend of stalk symplexies are the main other evolutionary traits. Nonfunctional articulations are frequently found at the paedomorphic pole of the heterochronic gradient, without clear derived characters. Classification of pentacrinids mainly based on such symplesiomorphy or paedomorphic characters must be definitively abandoned. However, in post‐Palaeozoic stalked crinoids the scarcity of well‐preserved fossils, the high frequency of paedomorphy, and convergent adaptive characters makes phylogenetic reconstruction only based on morphological characters very difficult and speculative. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155 , 22–39. 相似文献
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9.
Seppo AM Saari Kirsi H Juuti Joanna H Palojärvi Kirsi M Väisänen Riitta-Liisa Rajaniemi Leena E Saijonmaa-Koulumies 《Acta veterinaria Scandinavica》2009,51(1):40
Background
Demodex gatoi is unique among demodectic mites. It possesses a distinct stubby appearance, and, instead of residing in the hair follicles, it dwells in the keratin layer of the epidermis, causing a pruritic and contagious skin disease in cats. Little is known of the occurrence of D. gatoi in Europe or control of D. gatoi infestation. 相似文献10.
Jossi Hillel Martien AM Groenen Michèle Tixier-Boichard Abraham B Korol Lior David Valery M Kirzhner Terry Burke Asili Barre-Dirie Richard PMA Crooijmans Kari Elo Marcus W Feldman Paul J Freidlin Asko M?ki-Tanila Marian Oortwijn Pippa Thomson Alain Vignal Klaus Wimmers Steffen Weigend 《遗传、选种与进化》2003,35(6):533-557
In a project on the biodiversity of chickens funded by the European Commission (EC), eight laboratories collaborated to assess the genetic variation within and between 52 populations from a wide range of chicken types. Twenty-two di-nucleotide microsatellite markers were used to genotype DNA pools of 50 birds from each population. The polymorphism measures for the average, the least polymorphic population (inbred C line) and the most polymorphic population (Gallus gallus spadiceus) were, respectively, as follows: number of alleles per locus, per population: 3.5, 1.3 and 5.2; average gene diversity across markers: 0.47, 0.05 and 0.64; and proportion of polymorphic markers: 0.91, 0.25 and 1.0. These were in good agreement with the breeding history of the populations. For instance, unselected populations were found to be more polymorphic than selected breeds such as layers. Thus DNA pools are effective in the preliminary assessment of genetic variation of populations and markers. Mean genetic distance indicates the extent to which a given population shares its genetic diversity with that of the whole tested gene pool and is a useful criterion for conservation of diversity. The distribution of population-specific (private) alleles and the amount of genetic variation shared among populations supports the hypothesis that the red jungle fowl is the main progenitor of the domesticated chicken. 相似文献