Population size and land use affect the genetic variation and performance of the endangered plant species <Emphasis Type="Italic">Dianthus seguieri</Emphasis> ssp. <Emphasis Type="Italic">glaber</Emphasis>

Human activity and land use changes in the past decades have led to landscape homogenization and small-scale fragmentation of grassland habitats in most regions of central Europe. As a result, populations of many grassland species are small and strongly fragmented, facing extinction due to genetic depauperation and local maladaptation in remnant habitats. In this study, remaining populations of the strongly endangered grassland species Dianthus seguieri ssp. glaber (“Ragged Pink”) in Bavaria were investigated in order to evaluate the environmental factors influencing its genetic variation and performance. We first evaluated habitat, vegetation and population structure. Species performance was then studied by assessing the number of generative shoots, flowers and fertile capsules; and evaluating seed weight and seed viability. Finally, genetic variation was analyzed using molecular markers (AFLPs). Our analyses revealed that population size and land use abandonment have the strongest impact on genetic variation and species’ performance. Large and extended populations were most variable. 72 % of overall genetic variability of Dianthus seguieri ssp. glaber was found to be within populations, whereas 28 % remained between populations. Increased vegetation height and coverage, and a high proportion of gramineous species resulting from the lack of land use, reduced genetic variation, effective fruit and seed set. Our study shows that both population size and land use abandonment need to be considered to ensure the long term protection of endangered plant species. Maintaining an open habitat structure and adequate soil nutrient conditions through targeted annual mowing regime, over-storey vegetation trimming and green waste removal and the establishment of vegetation buffer strips will allow this species’ persistence and continuous recruitment.     

利用恒河婴猴模型对肠道病毒71型传播感染特征的生物学分析

本文在前期工作基础上,进一步对肠道病毒71型(EV71)从恒河婴猴的感染个体向其他未感染个体传播的可能性及相关生物学特性做了初步分析.通过喷雾形式经呼吸道感染1~2月龄恒河婴猴(A组);在观察临床症状同时,于感染后第7天,取该组动物粪便处理后,将上清液以喷雾形式经呼吸道感染新的婴猴个体(B组),随后对该次代感染个体进行...     

Epidemiological tracking and population assignment of the non-clonal bacterium, Burkholderia pseudomallei

Rapid assignment of bacterial pathogens into predefined populations is an important first step for epidemiological tracking. For clonal species, a single allele can theoretically define a population. For non-clonal species such as Burkholderia pseudomallei, however, shared allelic states between distantly related isolates make it more difficult to identify population defining characteristics. Two distinct B. pseudomallei populations have been previously identified using multilocus sequence typing (MLST). These populations correlate with the major foci of endemicity (Australia and Southeast Asia). Here, we use multiple Bayesian approaches to evaluate the compositional robustness of these populations, and provide assignment results for MLST sequence types (STs). Our goal was to provide a reference for assigning STs to an established population without the need for further computational analyses. We also provide allele frequency results for each population to enable estimation of population assignment even when novel STs are discovered. The ability for humans and potentially contaminated goods to move rapidly across the globe complicates the task of identifying the source of an infection or outbreak. Population genetic dynamics of B. pseudomallei are particularly complicated relative to other bacterial pathogens, but the work here provides the ability for broad scale population assignment. As there is currently no independent empirical measure of successful population assignment, we provide comprehensive analytical details of our comparisons to enable the reader to evaluate the robustness of population designations and assignments as they pertain to individual research questions. Finer scale subdivision and verification of current population compositions will likely be possible with genotyping data that more comprehensively samples the genome. The approach used here may be valuable for other non-clonal pathogens that lack simple group-defining genetic characteristics and provides a rapid reference for epidemiologists wishing to track the origin of infection without the need to compile population data and learn population assignment algorithms.     

A Scalable Open-Source Pipeline for Large-Scale Root Phenotyping of Arabidopsis

Large-scale phenotyping of multicellular organisms is one of the current challengesin biology. We present a comprehensive and scalable pipeline that allows for theefficient phenotyping of root growth traits on a large scale. This includes ahigh-resolution, low-cost acquisition setup as well as the automated image processingsoftware BRAT. We assess the performance of this pipeline in Arabidopsisthaliana under multiple growth conditions and show its utility byperforming genome-wide association studies on 16 root growth traits quantified byBRAT each day during a 5-d time-course experiment. The most significantly associatedgenome region for root growth rate is a locus encoding a calcium sensing receptor. Wefind that loss of function and overexpression of this gene can significantly alterroot growth in a growth condition dependent manner and that the minor natural alleleof the Calcium Sensor Receptor locus is highly significantlyenriched in populations in coastal areas, demonstrating the power of our approach toidentify regulators of root growth that might have adaptive relevance.     

N-Bromosuccinimide fragments of protein A24 (uH2A): an implication that ubiquitin is the precursor of conjugation in vivo

Chromatin protein A24 has a Y-branched structure in which the carboxyl terminus of ubiquitin is connected through a glycylglycine bridge to the ε-NH₂ of lysine 119 of histone 2A. In the present study, fragments of protein A24, histone 2A and ubiquitin obtained by cleavage at tryosines with N-bromosuccinimide were subjected to two-dimensional polyacrylamide gel electrophoresis and amino acid analysis. The fragmentation patterns and their compositions indicated the absence of an additional polypeptide between arginine 74 of ubiquitin and the glycyglycine bridge.     

Pseudouridine residues in the 5′-terminus of uridine-rich nuclear RNA I (U1 RNA)

The primary nucleotide sequence was reported earlier for U1 RNA (Reddy et al, (1974) J. Biol. Chem. $\text{249}$, 6486–6494), an snRNA implicated in splicing of HnRNAs. In view of the presence of homologous pseudouridine (ψ) residues in 5′-ends of several highly conserved U-snRNAs and the recent report of modified bases in the U1 RNA structure (Branlant et al, (1980) Nucleic Acids Res. $\text{8}$, 4143–4154) a study was made for the presence of ψ and other modified nucleotides in the 5′-end of the U1 RNA. Identification of ψ residues at positions 6 and 7, shows the 5′-sequence of U1 RNA is: m₃², 2,7 GpppAm-Um-A-C-ψ-ψ-A-C-C-U-G-G-C-A-G-G-G-G-A-G-A-U-A-C. The ψ residues in place of U at positions 6 and 7 may affect the binding of U1 RNA at intron-exon splice junctions.     

Conformational States of ABC Transporter MsbA in a Lipid Environment Investigated by Small-Angle Scattering Using Stealth Carrier Nanodiscs

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Soil inorganic carbon storage pattern in China

Soils with pedogenic carbonate cover about 30% (3.44 × 10⁶ km²) of China, mainly across its arid and semiarid regions in the Northwest. Based on the second national soil survey (1979–1992), total soil inorganic carbon (SIC) storage in China was estimated to be 53.3±6.3 PgC (1 Pg=10¹⁵ g) to the depth investigated to 2 m. Soil inorganic carbon storages were 4.6, 10.6, 11.1, and 20.8 Pg for the depth ranges of 0–0.1, 0.1–0.3, 0.3–0.5, and 0.5–1 m, respectively. Stocks for 0.1, 0.3, 0.5, and 1 m of depth accounted for 8.7%, 28.7%, 49.6%, and 88.9% of total SIC, respectively. In contrast with soil organic carbon (SOC) storage, which is highest under 500–800 mm yr⁻¹ of mean precipitation, SIC storage peaks where mean precipitation is <400 mm yr⁻¹. The amount and vertical distribution of SIC was related to climate and land cover type. Content of SIC in each incremental horizon was positively related with mean annual temperature and negatively related with mean annual precipitation, with the magnitude of SIC content across land cover types showing the following order: desert, grassland >shrubland, cropland >marsh, forest, meadow. Densities of SIC increased generally with depth in all ecosystem types with the exception of deserts and marshes where it peaked in intermediate layers (0.1–0.3 m for first and 0.3–0.5 m for latter). Being an abundant component of soil carbon stocks in China, SIC dynamics and the process involved in its accumulation or loss from soils require a better understanding.