The yeast nucleoporin Nup2p is involved in nuclear export of importin alpha/Srp1p.

The importin alpha.beta heterodimer mediates nuclear import of proteins containing classical nuclear localization signals. After carrying its cargo into the nucleus, the importin dimer dissociates, and Srp1p (the yeast importin alpha subunit) is recycled to the cytoplasm in a complex with Cse1p and RanGTP. Nup2p is a yeast FXFG nucleoporin that contains a Ran-binding domain. We find that export of Srp1p from the nucleus is impaired in Deltanup2 mutants. Also, Srp1p fusion proteins accumulate at the nuclear rim in wild-type cells but accumulate in the nuclear interior in Deltanup2 cells. A deletion of NUP2 shows genetic interactions with mutants in SRP1 and PRP20, which encodes the Ran nucleotide exchange factor. Srp1p binds directly to an N-terminal domain of Nup2p. This region of Nup2p is sufficient to allow accumulation of an Srp1p fusion protein at the nuclear rim, but the C-terminal Ran-binding domain of Nup2p is required for efficient Srp1p export. Formation of the Srp1p.Cse1p. RanGTP export complex releases Srp1p from its binding site in Nup2p. We propose that Nup2p may act as a scaffold that facilitates formation of the Srp1p export complex.     

Gene-based microsatellites for cassava (Manihot esculenta Crantz): prevalence, polymorphisms, and cross-taxa utility

Background  

Cassava (Manihot esculenta Crantz), a starchy root crop grown in tropical and subtropical climates, is the sixth most important crop in the world after wheat, rice, maize, potato and barley. The repertoire of simple sequence repeat (SSR) markers for cassava is limited and warrants a need for a larger number of polymorphic SSRs for germplasm characterization and breeding applications.     

Analysis of the meiosis in the F_1 hybrids of Longiflorum × Asiatic(LA) of lilies(Lilium) using genomic in situ hybridization

Longiflorum and Asiatic lilies of the genus Lilium of the family Liliaceae are two important groups of modern lily cultivars.One of the main trends of lily breeding is to realize introgression between these groups.With cut style pollination and embryo rescue,distant hybrids between the two groups have been obtained.However,the F1 hybrids are highly sterile or some of them could produce a small number of 2n gametes,and their BC1 progenies are usually triploids.Dutch lily breeders have selected many cultivars...     

Assessing the Validity of Self-Rated Health with the Short Physical Performance Battery: A Cross-Sectional Analysis of the International Mobility in Aging Study

ObjectiveThe aim of this study was to explore the validity of self-rated health across different populations of older adults, when compared to the Short Physical Performance Battery.DesignCross-sectional analysis of the International Mobility in Aging Study.SettingFive locations: Saint-Hyacinthe and Kingston (Canada), Tirana (Albania), Manizales (Colombia), and Natal (Brazil).ParticipantsOlder adults between 65 and 74 years old (n = 1,995).MethodsThe Short Physical Performance Battery (SPPB) was used to measure physical performance. Self-rated health was assessed with one single five-point question. Linear trends between SPPB scores and self-rated health were tested separately for men and women at each of the five international study sites. Poor physical performance (independent variable) (SPPB less than 8) was used in logistic regression models of self-rated health (dependent variable), adjusting for potential covariates. All analyses were stratified by gender and site of origin.ResultsA significant linear association was found between the mean scores of the Short Physical Performance Battery and ordinal categories of self-rated health across research sites and gender groups. After extensive control for objective physical and mental health indicators and socio-demographic variables, these graded associations became non-significant in some research sites.ConclusionThese findings further confirm the validity of SRH as a measure of overall health status in older adults.     

Carbon Balance of Tall Fescue (Festuca arundinacea Schreb.): Effects of Nitrogen Fertilization and the Growing Season

The C balance of a tall fescue sward grown under different ratesof N fertilization in summer, autumn, and spring was calculatedusing models derived from measurements of shoot growth, canopygross photosynthesis, shoot respiration and of C partitioningto the roots. Under the diverse growing conditions associatedwith the seasons and the N fertilization, C utilization forabove- and below-ground biomass accumulation never exceeded39 and 14% of the canopy gross photosynthesis, respectively.Carbon losses attributed to root respiration and exudation,which were estimated by difference between canopy net photosynthesisand total growth, ranged between 3 and 30% of canopy gross photosynthesis.Seasonal differences in shoot growth could be attributed tothe amount of intercepted radiation, the radiation-use efficiencyand the C partitioning to the roots. The effect of N deficiencyon shoot growth can be attributed to its effects on canopy photosynthesis(principally resulting from changes in intercepted photosyntheticallyactive radiation) and C partitioning. In comparison with theeffect on shoot growth, the effect of the N deficiency on thecanopy gross photosynthesis per unit of light intercepted overthe regrowth cycle was limited. It is concluded that most ofthe effect of N fertilization on shoot growth is due to changesin C partitioning which result in faster leaf area developmentand greater light interception.Copyright 1994, 1999 AcademicPress Tall rescue, Festuca arundinacea Schreb., carbon balance, nitrogen, grass, fertilization