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101.
Jamie Alison Jake M. Alexander Nathan Diaz Zeugin Yoko L. Dupont Evelin Iseli Hjalte M. R. Mann Toke T. Hye 《Biology letters》2022,18(7)
Recent decades have seen a surge in awareness about insect pollinator declines. Social bees receive the most attention, but most flower-visiting species are lesser known, non-bee insects. Nocturnal flower visitors, e.g. moths, are especially difficult to observe and largely ignored in pollination studies. Clearly, achieving balanced monitoring of all pollinator taxa represents a major scientific challenge. Here, we use time-lapse cameras for season-wide, day-and-night pollinator surveillance of Trifolium pratense (L.; red clover) in an alpine grassland. We reveal the first evidence to suggest that moths, mainly Noctua pronuba (L.; large yellow underwing), pollinate this important wildflower and forage crop, providing 34% of visits (bumblebees: 61%). This is a remarkable finding; moths have received no recognition throughout a century of T. pratense pollinator research. We conclude that despite a non-negligible frequency and duration of nocturnal flower visits, nocturnal pollinators of T. pratense have been systematically overlooked. We further show how the relationship between visitation and seed set may only become clear after accounting for moth visits. As such, population trends in moths, as well as bees, could profoundly affect T. pratense seed yield. Ultimately, camera surveillance gives fair representation to non-bee pollinators and lays a foundation for automated monitoring of species interactions in future. 相似文献
102.
Michael Hutchins Grace Mann Smith David C. Mead Susan Elbin Judie Steenberg 《Zoo biology》1991,10(2):147-164
Social behavior was studied in four (one male and three females) adult, captivebred Matschie's tree kangaroos (Dendrolagus matschiei) over a 124 day span in a large, naturalistic exhibit at the Woodland Park Zoological Gardens, Seattle, WA. A relatively high rate of social interaction occurred (15.2 per hour), over half of which consisted of approaches and nose contacts. The male initiated 54.1% of all social behaviors. Females tended to respond aggressively toward the male (avoid, bite, cuff, or swipe). The male initiated more affiliative behaviors and the females initiated more agonistic behaviors toward both the male and other females. A clear-cut dominance hierarchy could not be determined; reversals (i.e., cases in which the “subordinate” supplanted the “dominant”) occurred 43% of the time overall. Non-aggressive contact behavior consisted primarily of olfactory examination (nose contact). Allogrooming was extremely rare. The high level of agonism and lack of consistent association among individuals suggests that this species may be solitary in the wild. Two joeys were found dead on the floor during the course of the study, and based on previous findings, infanticide or behavioral stress was suspected to be the cause. Successful reproduction did not occur until females were isolated by removing other conspecifics from the enclosure. 相似文献
103.
Removal of serine phosphates from simian virus 40 large T antigen increases its ability to stimulate DNA replication in vitro but has no effect on ATPase and DNA binding. 总被引:8,自引:17,他引:8 下载免费PDF全文
The effect of phosphorylation on the ability of simian virus 40 large T antigen to stimulate DNA synthesis in vitro was tested. Treatment of affinity-purified large T antigen with calf intestinal alkaline phosphatase resulted in the removal of 70 to 80% of the phosphate residues. Only serine-bound phosphate residues were affected. Phosphatase-treated large T antigen stimulated in vitro DNA synthesis fourfold over the untreated control. The stimulation was strongest at early times of DNA replication. At later times, DNA replication proceeded at equal rates with dephosphorylated and untreated large T antigen. The ATPase activity of large T antigen was not affected by phosphatase treatment. The origin-binding activity of large T antigen was tested over a wide range of large T antigen to DNA ratios, including DNA excess, and in the presence and absence of carrier DNA. Under no condition was an effect of dephosphorylation of large T antigen on its DNA-binding activity observed. These findings might indicate that phosphorylation at serine residues modulates the interaction of large T antigen with cellular factors. During DNA synthesis large T antigen was substantially rephosphorylated by kinases in the HeLa cell extract. As shown by two-dimensional peptide mapping, this phosphorylation occurred at all known in vivo sites. No phosphatase and protease activities were detectable in the HeLa cell extract. 相似文献
104.
Krützen M Sherwin WB Connor RC Barré LM Van de Casteele T Mann J Brooks R 《Proceedings. Biological sciences / The Royal Society》2003,270(1514):497-502
Male bottlenose dolphins (Tursiops sp.) in Shark Bay have one of the most complex male societies outside humans. Two broad mating strategies have been identified in males. In the first strategy, there are two types of alliances: stable 'first-order' pairs and trios that herd individual females in reproductive condition, and 'second-order' teams of two first-order alliances (five or six individuals) that join forces against rivals in contests for females. In the alternative strategy, a 'super-alliance' of ca. 14 individuals, males form pairs or trios to herd females, but in contrast to the stable alliances, these pairs and trios are highly labile. Here, we show that males in stable first-order alliances and the derived second-order alliances are often strongly related, so that they may gain inclusive fitness benefits from alliance membership. By contrast, members of the super-alliance are no more closely related than expected by chance. Further, the strength of the association of alliance partners within the super-alliance, as measured by an index of joint participation in consorting a female, was not correlated with their genetic relatedness. Thus, within one population and one sex, it appears that there may be simultaneous operation of more than one mode of group formation. 相似文献
105.
106.
Assessment of binding indices and physiological responsiveness of the 5-HT2 receptor on human platelets 总被引:1,自引:0,他引:1
This is the first report of parallel studies of binding indices and physiological responsiveness of the "Serotonin-two" (5-HT2) receptor on the human platelet membrane. Binding indices were measured by a microassay employing [125I]ILSD as radioligand and ketanserin to define specific binding. A single receptor population was found, characterized by a KD of 1.69 +/- 0.45 nM and Bmax of 14.5 +/- 6.0 pmol/g protein in healthy subjects. Functional responsiveness of the platelet 5-HT2 receptor complex was assessed by measurement of the extent to which serotonin (10uM) augmented platelet aggregation induced by threshold concentrations of adenosine diphosphate (ADP). A statistically significant positive correlation was found between the number of platelet 5-HT2 receptor sites (Bmax) and the magnitude of the serotonin-amplified aggregation response (r = .70, n = 38, p less than 0.001). Assessment of binding indices and physiological responsiveness of the platelet 5-HT2 receptor complex should facilitate study of age, hormonal, disease, and drug effects on 5-HT2 receptor function in human subjects. 相似文献
107.
C J Mann T L Kaduce P H Figard A A Spector 《Archives of biochemistry and biophysics》1986,244(2):813-823
Cultured bovine aortic endothelial cells convert arachidonic acid to docosatetraenoic acid and also take up docosatetraenoic acid from the extracellular fluid. After a 24-h incubation with biosynthetically prepared [3H]docosatetraenoic acid, about 20% of the cellular fatty acid radioactivity was converted to arachidonic acid. Furthermore, in pulse-chase experiments, the decrease in phospholipid docosatetraenoic acid content was accompanied by an increase in arachidonic acid, providing additional evidence for retroconversion. These findings suggest that one possible function of docosatetraenoic acid in endothelial cells is to serve as a source of arachidonic acid. The endothelial cells can release docosatetraenoic acid when they are stimulated with ionophore A23187, but they do not form appreciable amounts of eicosanoids from docosatetraenoic acid. Enrichment of the endothelial cells with docosatetraenoic acid reduced their capacity to produce prostacyclin (PGI2) in response to ionophore A23187. This may be related to the fact that docosatetraenoic acid enrichment caused a 40% reduction in the arachidonic acid content of the inositol phosphoglycerides. In addition, less prostacyclin was formed when the enriched cells were incubated with arachidonic acid, suggesting that docosatetraenoic acid also may act as an inhibitor of prostaglandin synthesis in endothelial cells. 相似文献
108.
Lysine acetylome profiling uncovers novel histone deacetylase substrate proteins in Arabidopsis 下载免费PDF全文
Paul J Boersema Jan‐Oliver Jost Katharina Kramer Ahmet Bakirbas Julia Sindlinger Magdalena Plöchinger Dario Leister Glen Uhrig Greg BG Moorhead Jürgen Cox Michael E Salvucci Dirk Schwarzer Matthias Mann Iris Finkemeier 《Molecular systems biology》2017,13(10)
Histone deacetylases have central functions in regulating stress defenses and development in plants. However, the knowledge about the deacetylase functions is largely limited to histones, although these enzymes were found in diverse subcellular compartments. In this study, we determined the proteome‐wide signatures of the RPD3/HDA1 class of histone deacetylases in Arabidopsis. Relative quantification of the changes in the lysine acetylation levels was determined on a proteome‐wide scale after treatment of Arabidopsis leaves with deacetylase inhibitors apicidin and trichostatin A. We identified 91 new acetylated candidate proteins other than histones, which are potential substrates of the RPD3/HDA1‐like histone deacetylases in Arabidopsis, of which at least 30 of these proteins function in nucleic acid binding. Furthermore, our analysis revealed that histone deacetylase 14 (HDA14) is the first organellar‐localized RPD3/HDA1 class protein found to reside in the chloroplasts and that the majority of its protein targets have functions in photosynthesis. Finally, the analysis of HDA14 loss‐of‐function mutants revealed that the activation state of RuBisCO is controlled by lysine acetylation of RuBisCO activase under low‐light conditions. 相似文献
109.
Purification and characterization of perlucin and perlustrin, two new proteins from the shell of the mollusc Haliotis laevigata 总被引:4,自引:0,他引:4
Weiss IM Kaufmann S Mann K Fritz M 《Biochemical and biophysical research communications》2000,267(1):17-21
Two new proteins, named perlucin and perlustrin, with M(r) 17,000 and 13,000, respectively, were isolated from the shell of the mollusc Halotis laevigata (abalone) by ion-exchange chromatography and reversed-phase HPLC after demineralization of the shell in 10% acetic acid. The sequence of the first 32 amino acids of perlucin indicated that this protein belonged to a heterogeneous group of proteins consisting of a single C-type lectin domain. Perlucin increased the precipitation of CaCO(3) from a saturated solution, indicating that it may promote the nucleation and/or the growth of CaCO(3) crystals. With pancreatic stone protein (lithostathine) and the eggshell protein ovocleidin 17, this is the third C-type lectin domain protein isolated from CaCO(3) biominerals. This indicates that this type of protein performs an important but at present unrecognized function in biomineralization. Perlustrin was a minor component of the protein mixture and the sequence of the first 33 amino acids indicated a certain similarity to part of the much larger nacre protein lustrin A. 相似文献
110.