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1.
The nucleotide sequence data reported in this paper have been submitted to the GenBank nucleotide sequence database and have been assigned the accession numbers D37952, D37953, and D37954  相似文献   
2.
Pauliukonis  Nijole  Gough  Laura 《Plant Ecology》2004,173(1):1-15
Although clonal growth is a dominant mode of plant growth in wetlands, the importance of clonal integration, resource sharing among ramets, to individual ramet generations (mother and daughter) and entire clones of coexisting species has not been well investigated. This study evaluated the significance of clonal integration in four sedge species of varying ramet aggregations, from clump-forming species (Clumpers –Carex sterilis, Eleocharis rostellata), with tightly aggregated ramets (rhizomes<1cm), to runner species (Runners –Schoenoplectus acutus, Cladium mariscoides), with loosely aggregated ramets. We manipulated clonal integration by either severing connections between target mother and daughter ramets or leaving connections intact, and then planted them in an intact neighborhood of a fen in Michigan, USA. We measured growth parameters of original and newly produced ramets over two growing seasons and conducted a final biomass harvest, to address four hypotheses. First, we expected integrated clones to accumulate more biomass than severed clones. However, final clone-level biomass and ramet production were the same for both treatments in all species although severing initially stimulated ramet production by Schoenoplectus and produced a more compact ramet aggregation in Cladium. Second, we hypothesized that mother ramets would experience a cost of integration, through reduced ramet or biomass production, while daughters would experience a benefit, through increased resource availability from mothers. Mother ramets of Cladium suffered a cost from integration, while Schoenoplectus mothers suffered a slight cost and Carex daughters saw a slight benefit. Finally, we hypothesized that integration would be more active in runner species than in clumper species. Indeed, we documented more active integration in runners than clumpers, but none of the study species were dependent upon integration for growth or survival once daughter ramets were established with their own roots and shoots. This study demonstrates that integration between established ramets may not be the most important advantage to clonal growth in this wetland field site. The loss of integration elicited varied responses among coexisting species in their natural habitat, somewhat but not completely related to their growth form, suggesting that a combination of plant life history traits contributes to the dependence upon clonal integration among established ramets of clonal species.  相似文献   
3.
The purpose of this study was to analyse body size of Lithuanian newborns born in 1998 and 2004, and to compare results with the data from 1974. The main body size measurements - body weight, body length and body mass index (BMI) of 3281 (1705 boys and 1576 girls) live term singleton Lithuanian newborns' were analysed according to gestational age, sex and health status. The data were collected in the Clinic of Obstetrics and Gynaecology of Vilnius University (VU COG), and the comparison with the data of Lithuanian Medical Birth Register of (LMBR) was performed. No significant differences between height, weight and body mass index in 1998 and the same characteristics in 2004 were observed. Means and principal percentiles (10th, 50th, 90th) of body measurements of 37-42 weeks of gestational age newborns were obtained. The mean body length was 52.8/52.19 cm (boys/girls), body weight--3589/3454 g, BMI 12.82/12.64 correspondingly. The recent data were compared with the similar data from 1974 cohort. Statistically significant increment of body length of Lithuanian newborns was observed in all age and sex groups, whereas weight changes were less evident. The analysis of BMI demonstrated the following trend: newborns became longer, but not relatively heavier in comparison with the similar data 30 years ago. Hence, it is important to evaluate weight changes of neonate in relation with the changes in height. Further investigation of prevalence of neonatal macrosomia, possible factors of body size changes, their relationship to general health status and further health issues of the child should be explored.  相似文献   
4.
We have reported previously that Noggin is a heparin-binding protein and associates with the cell surface through heparan sulfate proteoglycans, where it remains functional for the binding of bone morphogenetic proteins (BMPs). Here we report that the binding of Noggin to the cell surface is highly selective for heparan sulfate and that specific structural features are required for the interaction. Noggin binds most efficiently to heparin sequences composed of 10 or more monosaccharides; N-, 6-O-, and 2-O-sulfates contribute to this interaction. In addition, we have shown that the developmentally regulated endosulfatase Qsulf1 selectively removes sulfate groups from the 6-O position of sugars within the most highly sulfated S domains of heparan sulfate, whereas 6-O-sulfates in the NA/NS domains are not substrates for the enzyme. The activity of Qsulf1 in cells in culture results in the release of Noggin from the cell surface and a restoration of BMP responsiveness to the cells. This shows that Noggin binds to the S domains of heparan sulfate and provides evidence that, in addition to modulating Wnt signaling in vivo by the release of heparan sulfate bound Wnt, Qsulf1 also modulates BMP signaling by the release of surface-bound Noggin.  相似文献   
5.
The bone microenvironment (e.g. glycosaminoglycans (GAGs), growth factors) plays a major role in bone resorption, especially in the formation of osteoclasts which differentiate from the hematopoietic lineage in the presence of RANKL. Previous studies revealed that GAGs may influence osteoclastogenesis, but data are very controversial, some studies showing an inhibitory effect of GAGs on osteoclastic differentiation whereas others demonstrated a stimulatory effect. To clarify their activities, we investigated the effect of 5 families of GAGs in three different models of human/mouse osteoclastogenesis. The present data revealed that heparin inhibited osteoclastogenesis in these three models, which was confirmed by a decrease in mRNA expression of osteoclastic markers and by an inhibition of the bone resorption capacity. We also demonstrated in RAW 264.7 cells that other families of GAGs different from heparin inhibited RANKL-induced osteoclastogenesis, and that this inhibition was dependent on the length and the level of sulfation of GAGs. In the present work, heparin did not bind to RANKL and did not modulate RANKL signaling. Heparin acted at 2 distinct steps of osteoclastogenesis from human CD14(+) cells: first, heparin strongly decreased the adherence of osteoclast precursors, and secondly inhibited osteoclasts to spread and to be active. Furthermore, the second action of heparin was reversible as the removal of heparin at the end of the culture time allowed the condensed cells to spread out and showed the formation of morphological active osteoclasts. The present work clearly evidences that GAGs inhibit osteoclastogenesis in vitro and strengthens the therapeutic interest of defined GAGs in osteolytic diseases.  相似文献   
6.
Transposon-mediated transformation was used to produce Anopheles stephensi that express single-chain antibodies (scFvs) designed to target the human malaria parasite, Plasmodium falciparum. The scFvs, m1C3, m4B7, and m2A10, are derived from mouse monoclonal antibodies that inhibit either ookinete invasion of the midgut or sporozoite invasion of salivary glands. The scFvs that target the parasite surface, m4B7 and m2A10, were fused to an Anopheles gambiae antimicrobial peptide, Cecropin A. Previously-characterized Anopheles cis-acting DNA regulatory elements were included in the transgenes to coordinate scFv production with parasite development. Gene amplification and immunoblot analyses showed promoter-specific increases in transgene expression in blood-fed females. Transgenic mosquito lines expressing each of the scFv genes had significantly lower infection levels than controls when challenged with P. falciparum.  相似文献   
7.
Changes in plasmalemma K+Mg2+-ATPase dephosphorylating activity and H+ transport were examined in freezing-tolerant and non-tolerant genotypes of the perennial grass species Festuca pratensis Huds. Enzyme activity and ΔμH+ were measured in plasmalemma fractions isolated from basal nodes and roots. Three types of experiments were undertaken: (i) a field experiment, utilizing the seasonal growth and cessation cycle of a perennial plant; (ii) a cold acclimation experiment in hydroponics; and (iii) an instant freezing test. A specific fluctuation in K+Mg2+-ATPase activity was found throughout the seasonal growth of the plants (i). The K+Mg2+-ATPase activity peaks for both the basal node and the root plasmalemma were determined early in the spring before the renewal of growth. The lowest activity values in roots occurred at the time approaching flowering, and in basal nodes at the transition into the growth cessation. The K+Mg2+-ATPase activity was approximately 50% lower in the basal node plasmalemma of freezing-tolerant plants than of non-tolerant ones, when assessed at the optimal growth stage in hydroponics. In hydroponics (ii) and in the freezing test (iii), temperature stress was followed by a more pronounced change in the level of K+Mg2+-ATPase activity than in that of H+ transport, and this change was more clearly differentiated in the basal node plasmalemma of contrasting genotypes than in the roots. Stress response was manifested differently in freezing-tolerant and non-tolerant plants at cold acclimation (4–2 °C) and at freezing (−8 °C) temperatures. Proton transport regulation via coupled changes in the hydrolysed ATP/transported proton ratio, as an attribute of freezing-tolerant plants, is discussed.  相似文献   
8.
The excision of specific DNA sequences from integrated transgenes in insects permits the dissection in situ of structural elements that may be important in controlling gene expression. Furthermore, manipulation of potential control elements in the context of a single integration site mitigates against insertion site influences of the surrounding genome. The cre-loxP site-specific recombination system has been used successfully to remove a marker gene from transgenic yellow fever mosquitoes, Aedes aegypti. A total of 33.3% of all fertile families resulting from excision protocols showed evidence of cre-loxP-mediated site-specific excision. Excision frequencies were as high as 99.4% within individual families. The cre recombinase was shown to precisely recognize loxP sites in the mosquito genome and catalyze excision. Similar experiments with the FLP/FRT site-specific recombination system failed to demonstrate excision of the marker gene from the mosquito chromosomes.  相似文献   
9.
Synthesis of N- and O-acyl derivatives of DL-serine and threo-DL-phenylserine was accomplished by a regioselective acylation of the corresponding amino acid. The residues introduced into amino acid structure contain hydrophobic long chain or aromatic, namely lauroyl, myristoyl and phenylacetyl moieties. The fungicidal activity against six strains of fungi was studied. Several compounds were found to be effective against growth of fungi, and O-myristoyl-DL-serine 2 and N-phenylacetyl-threo-DL-phenylserine 8 completely inhibited the growth of the mycelium of the fungus Verticillium dahliae.  相似文献   
10.
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