Microscale variation in alpine grasslands: AFLPs reveal a high level of genotypic diversity in Primula minima (Primulaceae)

The microscale variation and spatial genetic structure of the alpine plant species Primula minima L. was analysed using AFLPs. AFLP analysis based on three primer combinations and 123 fragments revealed no identical genotypes among the 86 studied samples from a 300 × 300 cm plot. Variation within the study plot was high: Nei's gene diversity was 0.22, Shannon's information index 0.33 and the percentage of polymorphic bands was 60.9. Cluster analysis revealed four main groups of genetically similar individuals and mapping these individuals resulted in a clear spatial pattern, with samples from the same group often located close together. The observed microscale structure was corroborated using a Mantel test, which revealed significant correlation of genetic and spatial distances, and by the results of a spatial autocorrelation analysis that indicated a high level of similarity between adjacent samples. An analysis of molecular variance revealed clear differentiation (18%) between the spatial groups. Overall gene flow within the plot was 1.11 and ranged from 0.33 between the spatially most distant groups to 2.33 between directly neighbouring groups. The extraordinary level of diversity detected in this study indicates an unexpectedly strong relevance of reproduction by seed for the species P. minima in alpine grasslands. The strong microscale variation suggests, however, that there is limited dispersal of seeds. Clonal reproduction is of subsidiary importance to sexual reproduction and seems to occur only over very small distances.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 155 , 549–556.     

Peripheral natural killer cell maturation depends on the transcription factor Aiolos

Natural killer (NK) cells are an innate lymphoid cell lineage characterized by their capacity to provide rapid effector functions, including cytokine production and cytotoxicity. Here, we identify the Ikaros family member, Aiolos, as a regulator of NK-cell maturation. Aiolos expression is initiated at the point of lineage commitment and maintained throughout NK-cell ontogeny. Analysis of cell surface markers representative of distinct stages of peripheral NK-cell maturation revealed that Aiolos was required for the maturation in the spleen of CD11b^highCD27⁻ NK cells. The differentiation block was intrinsic to the NK-cell lineage and resembled that found in mice lacking either T-bet or Blimp1; however, genetic analysis revealed that Aiolos acted independently of all other known regulators of NK-cell differentiation. NK cells lacking Aiolos were strongly hyper-reactive to a variety of NK-cell-mediated tumor models, yet impaired in controlling viral infection, suggesting a regulatory function for CD27⁻ NK cells in balancing these two arms of the immune response. These data place Aiolos in the emerging gene regulatory network controlling NK-cell maturation and function.     

Chloroplast DNA variation in the shrub Justicia areysiana (Acanthaceae) endemic to the monsoon affected coastal mountains of the southern Arabian Peninsula

The monsoon affected mountains of the southern Arabian Peninsula harbour in climatically favoured refugia vegetation elements of palaeo-African origin. To understand better the temporal and spatial differentiation of these refugia, chloroplast variation in Justicia areysiana Deflers (Acanthaceae), a shrub species endemic to the Yemeni and Omani mountains close to the Arabian Sea, was studied using PCR-RFLP and chloroplast microsatellite diversity. Eleven haplotypes were characterized and show a distinct geographical distribution pattern with a deep split between populations from south Yemeni fog oases and those from Hawf Mountains/Dhofar region in east Yemen and south Oman. Very limited haplotype diversity within populations (h_S = 0.15) and a high level of population differentiation (G_ST = 0.81) demonstrate the strong genetic isolation of populations from each other. Past oscillations between humid and arid periods connected with glacial and interglacial episodes in the Pleistocene and Holocene are considered responsible for the observed patterns of genetic variation.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 148 , 437–444.     

The artiodactyl <Emphasis Type="Italic">APOBEC3</Emphasis> innate immune repertoire shows evidence for a multi-functional domain organization that existed in the ancestor of placental mammals

Background  

APOBEC3 (A3) proteins deaminate DNA cytosines and block the replication of retroviruses and retrotransposons. Each A3 gene encodes a protein with one or two conserved zinc-coordinating motifs (Z1, Z2 or Z3). The presence of one A3 gene in mice (Z2–Z3) and seven in humans, A3A-H (Z1a, Z2a-Z1b, Z2b, Z2c-Z2d, Z2e-Z2f, Z2g-Z1c, Z3), suggests extraordinary evolutionary flexibility. To gain insights into the mechanism and timing of A3 gene expansion and into the functional modularity of these genes, we analyzed the genomic sequences, expressed cDNAs and activities of the full A3 repertoire of three artiodactyl lineages: sheep, cattle and pigs.     

Detection of a new important staging and wintering area of the White Stork Ciconia ciconia by satellite tracking

Since 1991, a large-scale satellite tracking study of White Stork Ciconia ciconia has followed 75 individuals along the eastern migration route, which passes across Israel into eastern Africa. Twenty-six of these birds travelled at least as far as the Sudan. Fifteen (58%) did not migrate to the eastern Sudan — the primary winter quarters in Africa suggested by ring recoveries — but flew to western Sudan and Chad and in one case even through Cameroon and into Nigeria. The significance of this new, important staging region for White Storks should be investigated urgently to establish the areas that are ecologically valuable for the conservation of this species.     

转基因细胞分泌乙型肝炎重组疫苗在儿童中的免疫原性初步研究

本文报告用转基因细胞B43分泌的乙型肝炎病毒表面抗原主蛋白经纯化制成的87-4批重组疫苗进行临床接种观察的结果,同时用8723-1批血源疫苗作对照。疫苗接种采用0、1、2月各接种1针的方案。重组疫苗共接种111名8～13岁儿童,分为20μg、10μg及5μg 3组,血源疫苗分为20μg、10μg 2组。所有儿童接种前检查乙型肝炎病毒表面抗原、抗体及核心抗体均阴性.20μg组1针后1个月,重组疫苗阳转率60.5％,血源疫苗为31％;2针后1个月,两种疫苗的阳转率分别为100％和72.4％;血源疫苗3针后1个月阳转率也仅79.3％。3针后1个月两种疫苗的抗体几何平均滴度(GMT)分别为492.7和207.4mIU。但重组疫苗6个月后血清抗体的GMT为628mIU。10μg组1针后1个月的阳转率重组疫苗为21.7％,血源疫苗为20.9％;2针后1个月分别为87％及62.8％;3针后1个月分别为100％及81.4％。抗体GMT分别为163.7和129.6mIU.5μg组的重组疫苗免疫后6个月100％阳转,其GMT为56mIU。结论认为无论从阳转率或几何平均滴度分析判断,重组疫苗均优于血源疫苗。     

THE COMPETITIVE DEMANDS OF ELITE MALE RINK HOCKEY

The aim of this study was to simulate the activity pattern of rink hockey by designing a specific skate test (ST) to study the energy expenditure and metabolic responses to this intermittent high-intensity exercise and extrapolate the results from the test to competition. Six rink hockey players performed, in three phases, the 20-metre multi-stage shuttle roller skate test, a tournament match and the ST. Heart rate was monitored in all three phases. Blood lactate, oxygen consumption, ventilation and respiratory exchange ratio were also recorded during the ST. Peak HR was 190.7±7.2 beats · min⁻¹. There were no differences in peak HR between the three tests. Mean HR was similar between the ST and the match (86% and 87% of HR_max, respectively). Peak and mean ventilation averaged 111.0±8.8 L · min⁻¹ and 70.3±14.0 L ^· min⁻¹ (60% of V_Emax), respectively. VO_2max was 56.3±8.4 mL · kg⁻¹ · min⁻¹, and mean oxygen consumption was 40.9±7.9 mL · kg^{−1 ·} min⁻¹ (70% of VO_2max). Maximum blood lactate concentration was 7.2±1.3 mmol · L-1. ST yielded an energy expenditure of 899.1±232.9 kJ, and energy power was 59.9±15.5 kJ · min⁻¹. These findings suggest that the ST is suitable for estimating the physiological demands of competitive rink hockey, which places a heavy demand on the aerobic and anaerobic systems, and requires high energy consumption.     

Ten years of elevated atmospheric carbon dioxide alters soil nitrogen transformations in a sheep‐grazed pasture

The increasing concentration of atmospheric carbon dioxide (CO₂) is expected to lead to enhanced competition between plants and microorganisms for the available nitrogen (N) in soil. Here, we present novel results from a ¹⁵N tracing study conducted with a sheep‐grazed pasture soil that had been under 10 years of CO₂ enrichment. Our study aimed to investigate changes in process‐specific gross N transformations in a soil previously exposed to an elevated atmospheric CO₂ (eCO₂) concentration and to examine indicators for the occurrence of progressive nitrogen limitation (PNL). Our results show that the mineralization–immobilization turnover (MIT) was enhanced under eCO₂, which was driven by the mineralization of recalcitrant organic N. The retention of N in the grassland was enhanced by increased dissimilatory NO₃^? reduction to NH₄⁺ (DNRA) and decreased NH₄⁺ oxidation. Our results indicate that heterotrophic processes become more important under eCO₂. We conclude that higher MIT of recalcitrant organic N and enhanced N retention are mechanisms that may alleviate PNL in grazed temperate grassland.     

Genomic prediction based on data from three layer lines using non-linear regression models

Background

Most studies on genomic prediction with reference populations that include multiple lines or breeds have used linear models. Data heterogeneity due to using multiple populations may conflict with model assumptions used in linear regression methods.

Methods

In an attempt to alleviate potential discrepancies between assumptions of linear models and multi-population data, two types of alternative models were used: (1) a multi-trait genomic best linear unbiased prediction (GBLUP) model that modelled trait by line combinations as separate but correlated traits and (2) non-linear models based on kernel learning. These models were compared to conventional linear models for genomic prediction for two lines of brown layer hens (B1 and B2) and one line of white hens (W1). The three lines each had 1004 to 1023 training and 238 to 240 validation animals. Prediction accuracy was evaluated by estimating the correlation between observed phenotypes and predicted breeding values.

Results

When the training dataset included only data from the evaluated line, non-linear models yielded at best a similar accuracy as linear models. In some cases, when adding a distantly related line, the linear models showed a slight decrease in performance, while non-linear models generally showed no change in accuracy. When only information from a closely related line was used for training, linear models and non-linear radial basis function (RBF) kernel models performed similarly. The multi-trait GBLUP model took advantage of the estimated genetic correlations between the lines. Combining linear and non-linear models improved the accuracy of multi-line genomic prediction.

Conclusions

Linear models and non-linear RBF models performed very similarly for genomic prediction, despite the expectation that non-linear models could deal better with the heterogeneous multi-population data. This heterogeneity of the data can be overcome by modelling trait by line combinations as separate but correlated traits, which avoids the occasional occurrence of large negative accuracies when the evaluated line was not included in the training dataset. Furthermore, when using a multi-line training dataset, non-linear models provided information on the genotype data that was complementary to the linear models, which indicates that the underlying data distributions of the three studied lines were indeed heterogeneous.

Electronic supplementary material

The online version of this article (doi:10.1186/s12711-014-0075-3) contains supplementary material, which is available to authorized users.