Effect of source germplasm and season on the in vivo haploid induction rate in tropical maize     

Aida Z. Kebede  Baldev S. Dhillon  Wolfgang Schipprack  Jose L. Araus  Marianne Bänziger  Kassa Semagn  Gregorio Alvarado  Albrecht E. Melchinger 《Euphytica》2011,180(2):219-226

For in vivo production of doubled haploid (DH) lines in maize, the rate of haploid induction is of crucial importance. Maternal haploid induction depends primarily on the inducer used as a pollinator. However, the source germplasm used as a maternal parent and the environmental conditions for induction may also influence haploid induction and these aspects have not been examined in tropical maize so far. The objectives of our study were to (i) monitor the variation for haploid induction rate (HIR) among diverse source germplasm in tropical maize, (ii) determine the relative importance of general (GCA) and specific (SCA) combining abilities for HIR, and (iii) investigate the influence of summer and winter seasons and genotype × season interactions on this trait. Ten inbreds were mated in a half diallel design. The resulting 45 F₁ single crosses were pollinated with the haploid inducer hybrid RWS × UH400 during the summer 2008 and winter 2009 seasons in a lowland tropical environment in Mexico. HIR of the single crosses averaged over seasons ranged from 2.90 to 9.66% with an overall mean of 6.74%. Mean HIR was significantly (P < 0.01) higher during the winter (7.37%) than summer season (6.11%). Significant (P < 0.01) variation was observed due to GCA effects of parental inbreds of single crosses but not for SCA, GCA × season and SCA × season interactions. Our study underpins that a higher HIR in tropical maize can be obtained by selecting appropriate source germplasm and undertaking pollination under favorable environmental conditions.  相似文献   

Development. Making sense of the sensory lineage     

Bronner-Fraser M 《Science (New York, N.Y.)》2004,303(5660):966-968

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CX3CR1-mediated dendritic cell access to the intestinal lumen and bacterial clearance   总被引：3，自引：0，他引：3  

Niess JH  Brand S  Gu X  Landsman L  Jung S  McCormick BA  Vyas JM  Boes M  Ploegh HL  Fox JG  Littman DR  Reinecker HC 《Science (New York, N.Y.)》2005,307(5707):254-258

Dendritic cells (DCs) and macrophages are critical to innate and adaptive immunity to the intestinal bacterial microbiota. Here, we identify a myeloid-derived mucosal DC in mice, which populates the entire lamina propria of the small intestine. Lamina propria DCs were found to depend on the chemokine receptor CX3CR1 to form transepithelial dendrites, which enable the cells to directly sample luminal antigens. CX3CR1 was also found to control the clearance of entero-invasive pathogens by DCs. Thus, CX3CR1-dependent processes, which control host interactions of specialized DCs with commensal and pathogenic bacteria, may regulate immunological tolerance and inflammation.  相似文献   

Reward-predictive cues enhance excitatory synaptic strength onto midbrain dopamine neurons     

Stuber GD  Klanker M  de Ridder B  Bowers MS  Joosten RN  Feenstra MG  Bonci A 《Science (New York, N.Y.)》2008,321(5896):1690-1692

Using sensory information for the prediction of future events is essential for survival. Midbrain dopamine neurons are activated by environmental cues that predict rewards, but the cellular mechanisms that underlie this phenomenon remain elusive. We used in vivo voltammetry and in vitro patch-clamp electrophysiology to show that both dopamine release to reward predictive cues and enhanced synaptic strength onto dopamine neurons develop over the course of cue-reward learning. Increased synaptic strength was not observed after stable behavioral responding. Thus, enhanced synaptic strength onto dopamine neurons may act to facilitate the transformation of neutral environmental stimuli to salient reward-predictive cues.  相似文献   

A haptoglobin-hemoglobin receptor conveys innate immunity to Trypanosoma brucei in humans     

Vanhollebeke B  De Muylder G  Nielsen MJ  Pays A  Tebabi P  Dieu M  Raes M  Moestrup SK  Pays E 《Science (New York, N.Y.)》2008,320(5876):677-681

The protozoan parasite Trypanosoma brucei is lysed by apolipoprotein L-I, a component of human high-density lipoprotein (HDL) particles that are also characterized by the presence of haptoglobin-related protein. We report that this process is mediated by a parasite glycoprotein receptor, which binds the haptoglobin-hemoglobin complex with high affinity for the uptake and incorporation of heme into intracellular hemoproteins. In mice, this receptor was required for optimal parasite growth and the resistance of parasites to the oxidative burst by host macrophages. In humans, the trypanosome receptor also recognized the complex between hemoglobin and haptoglobin-related protein, which explains its ability to capture trypanolytic HDLs. Thus, in humans the presence of haptoglobin-related protein has diverted the function of the trypanosome haptoglobin-hemoglobin receptor to elicit innate host immunity against the parasite.  相似文献   

Recombination of human mitochondrial DNA   总被引：1，自引：0，他引：1  

Kraytsberg Y  Schwartz M  Brown TA  Ebralidse K  Kunz WS  Clayton DA  Vissing J  Khrapko K 《Science (New York, N.Y.)》2004,304(5673):981

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Ecology. Rapid domestication of marine species     

Duarte CM  Marbá N  Holmer M 《Science (New York, N.Y.)》2007,316(5823):382-383

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Avian H5N1 influenza in cats     

Kuiken T  Rimmelzwaan G  van Riel D  van Amerongen G  Baars M  Fouchier R  Osterhaus A 《Science (New York, N.Y.)》2004,306(5694):241

During the 2003 to 2004 outbreak of avian influenza A (H5N1) virus in Asia, there were anecdotal reports of fatal infection in domestic cats, although this species is considered resistant to influenza. We experimentally inoculated cats with H5N1 virus intratracheally and by feeding them virus-infected chickens. The cats excreted virus, developed severe diffuse alveolar damage, and transmitted virus to sentinel cats. These results show that domestic cats are at risk of disease or death from H5N1 virus, can be infected by horizontal transmission, and may play a role in the epidemiology of this virus.  相似文献   

Longitudinal trends in pH and aluminum chemistry of the Coxing Kill,Ulster County,New York     

Alexandra M. Shultz  Marianne H. Begemann  Denise A. Schmidt  Kathleen C. Weathers 《Water, air, and soil pollution》1993,69(1-2):113-125

The purpose of this work was to characterize the Al chemistry along the longitudinal pH gradient of the Coxing Kill and thereby provide a basis for an in depth study of aluminum chemistry and transport as a function of pH. Water samples were collected along the pH gradient and analyzed for monomeric Al species, strong acid anions, base cations, ammonium, dissolved organic C and dissolved silica. Inorganic monomeric Al, organic momonmeric Al and dissolved organic C decreased in concentration as the stream's drainage area and pH increased. The ratio of organic to inorganic monomeric Al and the concentration of all other species increased with increasing pH. An abrupt change in stream chemistry occurred in conjunction with the gradual changes expected for a low order stream draining an acid sensitive watershed impacted by acid deposition. This abrupt change partially resulted from geological characteristics of the watershed.  相似文献   

Consequences of the spatial configuration of resources for the distribution and dynamics of the endangered Parnassius apollo butterfly     

Marianne S. Fred  Robert B. O’Hara 《Biological conservation》2006,130(2):183-192

Based on several years of data from two populations of the endangered Apollo butterfly (Parnassius apollo, L. 1758), we study how the amount and spatial location of patches of larval (host-plant) and adult (nectar plant) resources affects the distribution of females and their larval offspring in the following year. In the coastal population (nectar-plant and host-plant patches spatially segregated), females moved frequently between patches to aggregate on larger host-plant patches close to nectar-plant patches. In the archipelago population (where nectar-plants and host-plants co-occur), the abundance of females increased with higher proximity to other host-plant patches and with more nectar-plants on the patch. Next year’s larval abundance correlated with the abundance of females in the previous season in both populations. A model of the population dynamics in the two populations in relation to the spatial configuration of nectar and host-plant patches showed that the spatial configuration of larval and adult resources had population-dynamical consequences. In many organisms, different life-history stages use different resources. Incorporation of information on the location and abundance of adult resources can provide additional insight for the suitability of a particular landscape in harbouring a population.  相似文献