FT overexpression induces precocious flowering and normal reproductive development in Eucalyptus

Eucalyptus trees are among the most important species for industrial forestry worldwide. However, as with most forest trees, flowering does not begin for one to several years after planting which can limit the rate of conventional and molecular breeding. To speed flowering, we transformed a Eucalyptus grandis × urophylla hybrid (SP7) with a variety of constructs that enable overexpression of FLOWERING LOCUS T (FT). We found that FT expression led to very early flowering, with events showing floral buds within 1–5 months of transplanting to the glasshouse. The most rapid flowering was observed when the cauliflower mosaic virus 35S promoter was used to drive the Arabidopsis thaliana FT gene (AtFT). Early flowering was also observed with AtFT overexpression from a 409S ubiquitin promoter and under heat induction conditions with Populus trichocarpa FT1 (PtFT1) under control of a heat‐shock promoter. Early flowering trees grew robustly, but exhibited a highly branched phenotype compared to the strong apical dominance of nonflowering transgenic and control trees. AtFT‐induced flowers were morphologically normal and produced viable pollen grains and viable self‐ and cross‐pollinated seeds. Many self‐seedlings inherited AtFT and flowered early. FT overexpression‐induced flowering in Eucalyptus may be a valuable means for accelerating breeding and genetic studies as the transgene can be easily segregated away in progeny, restoring normal growth and form.     

Causes and characteristics of reverse bird migration: an analysis based on radar,radio tracking and ringing at Falsterbo,Sweden

That birds migrate in the reverse direction of the expected is a phenomenon of regular occurrence which has been observed at many sites. Here we use three different methods; tracking radar, radiotelemetry and ringing, to characterize the flights of these reverse migrants and investigate possible causes of reverse migration of nocturnally migrating passerines during autumn migration at Falsterbo peninsula, Sweden. Using these different methods we investigated both internal factors, such as age and fuel load, and external factors such as weather variables, competition and predation risk. Birds flying in the reverse direction were more likely to be lean and to be juveniles. Reverse migration was also more common with overcast skies and winds with north and east components. We did not find any effect of temperature, visibility, number of migrating sparrowhawks, or the total number of ringed birds at the site on the day of departure. We found that reverse migration is characterized by slower flight speeds (airspeed) at high altitudes and that it takes place later in the night than forward migration.     

Wood addition in the hatchery and river environments affects post‐release performance of overwintering brown trout

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Leapfrog migration and residents: New migratory habits in Swedish Greylag geese

Knowledge about intraspecific and individual variation in bird migration behavior is important to predict spatiotemporal distribution, patterns of phenology, breeding success, and interactions with the surrounding environment (e.g., human livelihoods). Such variation is key to adaptive, evolutionary responses, i.e., how individuals respond spatiotemporally to the environment to maximize fitness. In this study we used GPS location data from one to three full annual cycles from 76 Greylag geese (Anser anser) to test the hypothesis that geese originating at five latitudinally separated capture sites in Sweden have different migration strategies. We also assessed individual consistency in movement strategy over consecutive annual cycles. We used the scale‐independent net squared displacement modeling framework to quantify variables of autumn and spring migration for geese from each capture site: distance, timing, and duration. Our results demonstrate a positive correlation between migration distance and latitudinal origin. Geese from the northernmost site on average migrated farther south and about 15 times as far as the short‐moving or resident geese from the two southernmost sites. Movement strategies of individual geese varied considerably both within and among capture sites. Individual consistency in movement strategy from one annual cycle to the consecutive was high in geese from the northern sites moving the farthest, whereas the resident or short‐moving geese from the southernmost sites generally showed lower or no individual consistency. These changes have come about during a time span so short (i.e., ca. 35 years or 8–10 generations) that it can unlikely be explained by classical Darwinian between‐generation adaptation. Consequently, and given that young geese follow their parents during their first migration, we presume an important role of within‐family, inter‐generation change as a driver behind the large‐scale changed migration habits in Swedish Greylag geese.     

Glycosidase and phosphatase activities in U-937 and some clones and sublines

1. The activities of nine glycosidases, lysozyme and acid and alkaline phosphatases were compared in the histiocytic lymphoma cell line U-937 and a set of clones and sublines derived from this line. 2. The patterns of the different enzyme activities and selected enzyme ratios have been used as a method to distinguish between different clones and sublines. 3. Sublines with high lysozyme levels were rich in most cell-bound glycosidases. 4. During long-term growth distinct enzyme patterns of individual lines were preserved. 5. The enzyme pattern during a cell culture growth cycle was basically stable.     

Linkage disequilibrium mapping of the bolting gene in sea beet using AFLP markers

The possibility of using linkage disequilibrium mapping in natural plant populations was assessed. In studying linkage disequilibrium among 137 mapped AFLP markers in four populations of sea beet (Beta vulgaris ssp. maritima (L.) Arcang.) it was shown that tightly linked loci could be detected by screening for associations. It was hypothesized that the short distances spanned by linkage disequilibrium enable markers that are very tightly linked to a target gene to be identified. The hypothesis was tested by whole-genome screening of AFLP markers for association with the gene for the annual growth habit, the B gene, in a sample of 106 sea beets. Despite the dominant nature of AFLP, two markers showing significant linkage disequilibrium with the B gene were detected. The results indicate the potential use of linkage disequilibrium for gene mapping in natural plant populations.     

Production, purification, and luminometric analysis of recombinant Saccharomyces cerevisiae MET3 adenosine triphosphate sulfurylase expressed in Escherichia coli

ATP sulfurylase cDNA from MET3 on chromosome X of Saccharomyces cerevisiae was amplified and cloned, and recombinant ATP sulfurylase was expressed in Escherichia coli. The synthesis of ATP sulfurylase was directed by an expression system that employs the regulatory genes of the luminous bacterium Vibrio fischeri. A soluble, biologically active form was purified to electrophoretic homogeneity from lysates of recombinant E. coli by ammonium sulfate fractionation, ion-exchange chromatography, and gel filtration. The specific activity of the purified enzyme was estimated to 140 U/mg. The apparent molecular mass of the recombinant enzyme was determined by gel filtration to be 470 kDa, which indicates that the active enzyme is an octamer of identical subunits (the molecular mass of a single subunit is 59.3 kDa). The ATP sulfurylase activity was monitored in real time by a very sensitive bioluminometric method.     

Mutational scanning of PCR products by subtractive oligonucleotide hybridization analysis

Here, we describe a new approach for mutational scanning of PCR products through hybridization analysis between complementary oligonucleotides. Sets of overlapping probe oligonucleotides complementary to wild-type (WT) sequence are hybridized to microbead-immobilized PCR products under solution-like conditions. Mismatch-hybridization situations between a mutant sample and probe oligonucleotides result in higher remaining concentrations in solution of involved probe oligonucleotides. Post-hybridization supernatants are subsequently analyzed for their probe oligonucleotide compositions using surface plasmon resonance-based biosensor technology. Relative remaining probe oligonucleotide concentrations are monitored in real-time through hybridization analysis between probe oligonucleotides and their corresponding sensor-chip immobilized complementary counterparts. This allows for the construction of composition diagrams revealing the existence and approximate location of a mutation within an investigated sample DNA sequence. Applied on PCR products derived from clinical samples of microdissected tumor biopsies, single mutations in exons 6 and 7 of the human p53 tumor-suppressor gene were successfully detected and approximately localized.     

Molecular and cellular mechanisms of transepithelial iodide transport in the thyroid

Thyroid hormone is an essential regulator of developmental growth and metabolism in vertebrates. Iodine is a necessary constituent of thyroid hormone. Due to the scarcity and uneven distribution of iodine on the Earth's crust, the structure of the thyroid gland is adjusted to collect and store this element in order to secure a continuous supply of thyroid hormone throughout life. Still, disease resulting from hypothyroidism due to iodine deficiency is a global health problem, illustrating the great biological significance that iodine saving mechanisms have evolved. Iodide is accumulated together with prohormone (thyroglobulin) in the lumen of the thyroid follicles. The rate-limiting step of this transport is the sodium/iodide symporter located in the basolateral plasma membrane of the thyroid follicular cells. Iodide is also transferred across the apical plasma membrane into the lumen where hormonogenesis takes place. In this review, recent progress in the understanding of transepithelial iodide transport in the thyroid is summarized.