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351.
Every year billions of butterflies, dragonflies, moths and other insects migrate across continents, and considerable progress has been made in understanding population-level migratory phenomena. However, little is known about destinations and strategies of individual insects. We attached miniaturized radio transmitters (ca 300 mg) to the thoraxes of 14 individual dragonflies (common green darners, Anax junius) and followed them during their autumn migration for up to 12 days, using receiver-equipped Cessna airplanes and ground teams. Green darners exhibited distinct stopover and migration days. On average, they migrated every 2.9+/-0.3 days, and their average net advance was 58+/-11 km in 6.1+/-0.9 days (11.9+/-2.8 km d-1) in a generally southward direction (186+/-52 degrees). They migrated exclusively during the daytime, when wind speeds were less than 25 km h-1, regardless of wind direction, but only after two nights of successively lower temperatures (decrease of 2.1+/-0.6 degrees C in minimum temperature). The migratory patterns and apparent decision rules of green darners are strikingly similar to those proposed for songbirds, and may represent a general migration strategy for long-distance migration of organisms with high self-propelled flight speeds. 相似文献
352.
Clifford DL Folmes Grzegorz Sawicki Virgilio JJ Cadete Grant Masson Amy J Barr Gary D Lopaschuk 《Proteome science》2010,8(1):38
Background
During and following myocardial ischemia, glucose oxidation rates are low and fatty acids dominate as a source of oxidative metabolism. This metabolic phenotype is associated with contractile dysfunction during reperfusion. To determine the mechanism of this reliance on fatty acid oxidation as a source of ATP generation, a functional proteomics approach was utilized. 相似文献353.
Dumitru CD Antonysamy MA Gorski KS Johnson DD Reddy LG Lutterman JL Piri MM Proksch J McGurran SM Egging EA Cochran FR Lipson KE Tomai MA Gullikson GW 《Cancer immunology, immunotherapy : CII》2009,58(4):575-587
Innate immune stimulation with Toll-like receptor (TLR) agonists is a proposed modality for immunotherapy of melanoma. Here,
a TLR7/8 agonist, 3M-011, was used effectively as a single systemic agent against disseminated mouse B16-F10 melanoma. The investigation of the mechanism of antitumor action revealed that the agonist had no direct cytotoxic effects
on tumor cells tested in vitro. In addition, 3M-011 retained its effectiveness in scid/B6 mice and scid/NOD mice, eliminating the requirement for T and B cells, but lost its activity in beige (bg/bg) and NK1.1-immunodepleted mice, suggesting a critical role for natural killer (NK) cells in the antitumor response.
NK cytotoxicity was enhanced in vivo by the TLR7/8 agonist; this activation was long lasting, as determined by sustained expression of the activation marker CD69. Also, in human in vitro studies, 3M-011 potentiated
NK cytotoxicity. TLR7/8-mediated NK-dependent antitumor activity was retained in IFN-α/β receptor-deficient as well as perforin-deficient
mice, while depletion of IFN-γ significantly decreased the ability of 3M-011 to delay tumor growth. Thus, IFN-γ-dependent
functions of NK cell populations appear essential for cancer immunotherapy with TLR7/8 agonists.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
All authors are or were employed by 3M while this work was being conducted. 相似文献
354.
A nuclear gene for higher level phylogenetics: phosphoenolpyruvate carboxykinase tracks mesozoic-age divergences within Lepidoptera (Insecta) 总被引:3,自引:0,他引:3
The sequence of phosphoenolpyruvate carboxykinase (PEPCK) has been
previously identified as a promising candidate for reconstructing
Mesozoic-age divergences (Friedlander, Regier, and Mitter 1992, 1994). To
test this hypothesis more rigorously, 597 nucleotides of aligned PEPCK
coding sequence (approximately 30% of the coding region) were generated
from 18 species representing Mesozoic-age lineages of moths (Insecta:
Lepidoptera) and outgroup taxa. Relationships among basal Lepidoptera are
well established by morphological analysis, providing a strong test for the
utility of a gene which has not previously been used in systematics.
Parsimony and other phylogenetic analyses were conducted on nucleotides by
codon positions (nt1, nt2, nt3) separately and in combination, and on amino
acids, for comparison to the test phylogeny. The highest concordance was
achieved with nt1 + nt2, for which one of two most-parsimonious trees was
identical to the test phylogeny, and with all nucleotides when nt3 was
down-weighted sevenfold or higher, for which a single most-parsimonious
tree identical to the test phylogeny resulted. Substitutions in nt3
approached saturation in many, but not all, pairwise comparisons and their
exclusion or severe downweighting greatly increased the degree of
concordance with the test phylogeny. Neighbor-joining analysis confirms
this finding. The utility of PEPCK for phylogenetics is demonstrated over a
time span for which few other suitable genes are currently available.
相似文献
355.
Difference UV spectrophotometry is used to determine the conditional binding constants for aluminum to human transferrin in the presence of HCO3- of initial concentration 18 mM according to a two site model. The values obtained at 37 degrees C and pH 7.4 are: K1 = 3.0 (+/- 0.8) X 10(15) M-2, K2 = 2.9 (+/- 0.7) X 10(15) M-2 for the reactions: Tr + Al3+ + HCO3- = Tr-Al-HCO3 and Tr-Al-HCO3 + Al3+ + HCO3- = Tr-Al2-(HCO3)2 respectively. Possible consequences arising for the transport of aluminum in human serum are discussed. 相似文献
356.
357.
The effectiveness of adjustment by subclassification in removing bias in observational studies 总被引:14,自引:0,他引:14
W G Cochran 《Biometrics》1968,24(2):295-313
358.
The competitive equilibrium between aluminium and ferric ions for the binding sites of transferrin 总被引:4,自引:0,他引:4
Human transferrin is shown to bind 2 mol of aluminium per mol of protein using spectrophotometric titration. Competitive equilibrium between aluminium and ferric ions for transferrin binding sites is observed, and a value of 2.5 (+/- 0.4) X 10(15) M-1 is found for the apparent binding constant under physiological conditions. 相似文献
359.
Abstract. Large knots (>100 individuals) of adult horsehair worms ( Gordius difficilis ) were collected in several spring-fed habitats in Wisconsin and Minnesota. These aggregations were dominated numerically by males. Although distributions of length and diameter of males and females overlapped, females tended to be significantly longer and wider than males. Moreover, at any given length, females were wider than males. These findings confirm and add statistical support to previously published reports. 相似文献
360.
Of nine patients with uraemic osteomalacia, the underlying renal lesion was pyelonephritis in seven. All of the patients were characterized by impairment of acidifying power and severe metabolic acidosis. It is suggested that metabolic acidosis may be a definite factor in the pathogenesis of uraemic osteomalacia, possibly by reducing the proportion of trivalent phosphate in the plasma and/or by reducing plasma calcium. 相似文献