Abstract:
:Despite high predation pressure, planktonic copepods remain one of the most abundant groups on the planet. Their escape response provides one of most effective mechanisms to maximize evolutionary fitness. Owing to their small size (100 µm) compared with their predators (>1 mm), increasing viscosity is believed to have detrimental effects on copepods' fitness at lower temperature. Using high-speed digital holography we acquire 3D kinematics of the nauplius escape including both location and detailed appendage motion. By independently varying temperature and viscosity we demonstrate that at natural thermal extremes, contrary to conventional views, nauplii achieve equivalent escape distance while maintaining optimal velocity. Using experimental results and kinematic simulations from a resistive force theory propulsion model, we demonstrate that a shift in appendage timing creates an increase in power stroke duration relative to recovery stroke duration. This change allows the nauplius to limit losses in velocity and maintain distance during escapes at the lower bound of its natural thermal range. The shift in power stroke duration relative to recovery stroke duration is found to be regulated by the temperature dependence of swimming appendage muscle groups, not a dynamic response to viscosity change. These results show that copepod nauplii have natural adaptive mechanisms to compensate for viscosity variations with temperature but not in situations in which viscosity varies independent of temperature, such as in some phytoplankton blooms. Understanding the robustness of escapes in the wake of environmental changes such as temperature and viscosity has implications in assessing the future health of performance compensation.
journal_name
Proc Natl Acad Sci U S Aauthors
Gemmell BJ,Sheng J,Buskey EJdoi
10.1073/pnas.1212148110subject
Has Abstractpub_date
2013-03-19 00:00:00pages
4661-6issue
12eissn
0027-8424issn
1091-6490pii
1212148110journal_volume
110pub_type
杂志文章abstract::p150Glued was first identified as a polypeptide that copurifies with cytoplasmic dynein, the minus-end-directed microtubule-based motor protein, and has more recently been shown to be present as a member of the oligomeric dynactin complex, which includes the actin-related protein centractin (Arp-1). Dynactin is though...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.92.5.1634
更新日期:1995-02-28 00:00:00
abstract::The mountain pine beetle (Dendroctonus ponderosae Hopkins) is the most destructive pest of western North American pine forests. Adult males produce frontalin, an eight-carbon antiaggregation pheromone, via the mevalonate pathway, as part of several pheromones that initiate and modulate the mass attack of host trees. F...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1316498110
更新日期:2013-11-19 00:00:00
abstract::Climate change is expected to influence the capacities of the land and oceans to act as repositories for anthropogenic CO2 and hence provide a feedback to climate change. A series of experiments with the National Center for Atmospheric Research-Climate System Model 1 coupled carbon-climate model shows that carbon sink...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0504949102
更新日期:2005-08-09 00:00:00
abstract::The demonstration of enzymatic capabilities of certain RNAs, in addition to their well-known template properties, has led to the recognition that RNAs are the only biological macromolecules that can function both as genotype and phenotype, hence raising the possibility of Darwinian selection and precellular evolution ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.86.23.9370
更新日期:1989-12-01 00:00:00
abstract::An amine-functionalized derivative of 1,3-dipropyl-8-phenylxanthine has been prepared in tritiated form as a xanthine amine congener ([3H]XAC) for use as an antagonist radioligand for adenosine receptors. [3H]XAC has higher receptor affinity, higher specific activity, lower nonspecific membrane binding, and more favor...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.83.11.4089
更新日期:1986-06-01 00:00:00
abstract::Adipose tissue dysfunction is causally implicated in the impaired metabolic homeostasis associated with obesity; however, detailed mechanisms underlying dysregulated adipocyte functions in obesity remain to be elucidated. Here we searched for genes that provide a previously unknown mechanism in adipocyte metabolic fun...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1720475115
更新日期:2018-02-13 00:00:00
abstract::Nucleotide sequences that direct transcription of the human 5-lipoxygenase gene have been examined by ligation to the chloramphenicol acetyltransferase gene and determination of chloramphenicol acetyltransferase activity in transfected HeLa and HL-60 cells. Various lengths of 5'-flanking sequences up to 5.9 kilobase p...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.87.23.9073
更新日期:1990-12-01 00:00:00
abstract::The seventh cholera pandemic caused by Vibrio cholerae O1 El Tor (ET) has been superseded in Asia and Africa by altered ET possessing the cholera toxin (CTX) gene of classical (CL) biotype. The CL biotype of V. cholerae was isolated, along with prototypic and altered ET, during the 1991 cholera epidemic in Mexico and ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1323408111
更新日期:2014-07-08 00:00:00
abstract::Noncatalytic carbohydrate binding modules (CBMs) are components of glycoside hydrolases that attack generally inaccessible substrates. CBMs mediate a two- to fivefold elevation in the activity of endo-acting enzymes, likely through increasing the concentration of the appended enzymes in the vicinity of the substrate. ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1212034109
更新日期:2012-12-18 00:00:00
abstract::The very low density lipoprotein (VLDL) receptor is a recently cloned member of the low density lipoprotein (LDL) receptor family that mediates the binding and uptake of VLDL when overexpressed in animal cells. Its sequence is 94% identical in humans and rabbits and 84% identical in humans and chickens, implying a con...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.92.18.8453
更新日期:1995-08-29 00:00:00
abstract::In this era of unprecedented biodiversity loss and increased zoonotic disease emergence, it is imperative to understand the effects of biodiversity on zoonotic pathogen dynamics in wildlife. Whether increasing biodiversity should lead to a decrease or increase in infection prevalence, termed the dilution and amplifica...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1807106115
更新日期:2018-07-31 00:00:00
abstract::Thiamin diphosphate, the vitamin B1 coenzyme, plays critical roles in fundamental metabolic pathways that require acyl carbanion equivalents. Studies on chemical models and enzymes had suggested that these carbanions are resonance-stabilized as enamines. A crystal structure of this intermediate in pyruvate oxidase at ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1201280109
更新日期:2012-07-03 00:00:00
abstract::The relation between changes in brain and plasma concentrations of neurosteroids and the function and structure of gamma-aminobutyric acid type A (GABAA) receptors in the brain during pregnancy and after delivery was investigated in rats. In contrast with plasma, where all steroids increased in parallel, the kinetics ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.95.22.13284
更新日期:1998-10-27 00:00:00
abstract::Dendritic spines are of major importance in information processing and memory formation in central neurons. Estradiol has been shown to induce an increase of dendritic spine density on hippocampal neurons in vivo and in vitro. The neurotrophin brain-derived neurotrophic factor (BDNF) recently has been implicated in ne...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.95.19.11412
更新日期:1998-09-15 00:00:00
abstract::Prenatal stress exposure is associated with risk for psychiatric disorders later in life. This may be mediated in part via enhanced exposure to glucocorticoids (GCs), which are known to impact neurogenesis. We aimed to identify molecular mediators of these effects, focusing on long-lasting epigenetic changes. In a hum...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1820842116
更新日期:2020-09-22 00:00:00
abstract::Protein-protein interactions allow the retinoid X receptor (RXR) to bind to cognate DNA as a homo- or a heterodimer and to participate in mediating the effects of a variety of hormones on gene transcription. Here we report a systematic study of the oligomeric state of RXR in the absence of a DNA template. We have used...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.92.19.8645
更新日期:1995-09-12 00:00:00
abstract::We have examined the role of a cell surface galactosyltransferase, laminin, and laminin-binding protein (receptor) in the invasion of clonal derivatives of a murine adrenal carcinoma cell line. Although a 10-fold variation was found in the ability to invade a reconstituted basement membrane matrix, levels of intracell...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.86.16.6057
更新日期:1989-08-01 00:00:00
abstract::The current model to explain the organization of the mammalian nervous system is based on studies of anatomy, embryology, and evolution. To further investigate the molecular organization of the adult mammalian brain, we have built a gene expression-based brain map. We measured gene expression patterns for 24 neural ti...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0503357102
更新日期:2005-07-19 00:00:00
abstract::Magnetic ground states in solids often arise as a result of a delicate balance between competing factors. One currently active area of research in magnetic materials involves compounds in which long-range magnetic ordering at low temperatures is frustrated by the geometry of the crystalline lattice, a situation known ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0832394100
更新日期:2003-07-08 00:00:00
abstract::A metabolite of estradiol, 2-methoxyestradiol (2ME), inhibits angiogenesis in the chicken embryo chorioallantoic membrane assay. Since 2ME causes mitotic perturbations, we examined its interactions with tubulin. In our standard 1.0 M glutamate system (plus 1.0 mM MgCl2 at 37 degrees C), superstoichiometric concentrati...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.91.9.3964
更新日期:1994-04-26 00:00:00
abstract::The generalized master equations (GMEs) that contain multiple time scales have been derived quantum mechanically. The GME method has then been applied to a model of charge migration in proteins that invokes the hole hopping between local amino acid sites driven by the torsional motions of the floppy backbones. This mo...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.140196597
更新日期:2000-08-29 00:00:00
abstract::The mechanisms that are essential for the maintenance of nutrient status in breast milk are unclear. Our data demonstrate that the intestine via hypoxia-inducible factor (HIF)-2α is an essential regulatory mechanism for maintaining the quality of breast milk. During lactation, intestinal HIF-2α is highly increased, le...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1504891112
更新日期:2015-07-14 00:00:00
abstract::The post-translational proteolytic conversion of somatostatin-14 precursors was studied to characterize the enzyme system responsible for the production of the tetradecapeptide either from its 15-kDa precursor protein or from its COOH-terminal fragment, somatostatin-28. A synthetic undecapeptide Pro-Arg-Glu-Arg-Lys-Al...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.81.21.6662
更新日期:1984-11-01 00:00:00
abstract::We reported in previous studies that prostaglandin E2 (PGE2) has central effects of augmenting wakefulness and suppressing slow-wave sleep (SWS) and paradoxical sleep (PS) in rats. In the present study, we tested the effect of AH 6809, an antagonist of PGE2 receptors, on sleep-wake activities. AH 6809 in saline was in...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.86.14.5666
更新日期:1989-07-01 00:00:00
abstract::Metallophilicity is defined as the interaction among closed-shell metal centers, the origin of which remains controversial, particularly for the roles of spd orbital hybridization (mixing of the spd atomic orbitals of the metal atom in the molecular orbitals of metal complex) and the relativistic effect. Our studies r...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.2019265118
更新日期:2021-01-05 00:00:00
abstract::The Bill and Melinda Gates Foundation supports an ambitious portfolio of novel vaccines, drug regimens, and diagnostic tools for tuberculosis (TB). We elicited the expected efficacies and improvements of the novel interventions in discussions with the foundations managing their development. Using an age-structured mat...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0901720106
更新日期:2009-08-18 00:00:00
abstract::[3H]Forskolin bound to high- and low-affinity sites in the rat brain. The high-affinity site was discretely located, with highest densities in the striatum, nucleus accumbens, olfactory tubercule, substantia nigra, hippocampus, and the molecular layers of the cerebellum. This site did not correlate well with the distr...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.85.9.3216
更新日期:1988-05-01 00:00:00
abstract::We have examined the use of our bis(sulfonamide) diol ligand (1) in the asymmetric addition of phenyl groups to cyclic alpha,beta-unsaturated ketones. Good to excellent enantioselectivities have been obtained with cyclic enones bearing alkyl substituents in the 2 position (71-97% enantiomeric excess). Furthermore, exc...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0307119101
更新日期:2004-04-13 00:00:00
abstract::The ability to identify sequences in a randomly encoded polypeptide library that are capable of acquiring unique and stably folded structures would be valuable in the examination of protein-folding issues. The quality control system of the yeast secretory pathway prevents the release of incompletely folded polypeptide...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.102172099
更新日期:2002-05-14 00:00:00
abstract::Docosahexaenoic acid (DCHA), a major polyunsaturated acid component of fish lipid, is not a substrate for prostaglandin synthetase from ram seminal vesicles but is a strong competitive inhibitor (Ki, 0.36 microM) of the conversion by this enzyme of arachidonate (Km, 5.9 microM) to prostaglandins. In contrast, DCHA exh...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.80.12.3581
更新日期:1983-06-01 00:00:00