Abstract:
:The annual migration of ∼1.2 million wildebeest (Connochaetes taurinus) through the Serengeti Mara Ecosystem is the largest remaining overland migration in the world. One of the most iconic portions of their migration is crossing of the Mara River, during which thousands drown annually. These mass drownings have been noted, but their frequency, size, and impact on aquatic ecosystems have not been quantified. Here, we estimate the frequency and size of mass drownings in the Mara River and model the fate of carcass nutrients through the river ecosystem. Mass drownings (>100 individuals) occurred in at least 13 of the past 15 y; on average, 6,250 carcasses and 1,100 tons of biomass enter the river each year. Half of a wildebeest carcass dry mass is bone, which takes 7 y to decompose, thus acting as a long-term source of nutrients to the Mara River. Carcass soft tissue decomposes in 2-10 wk, and these nutrients are mineralized by consumers, assimilated by biofilms, transported downstream, or moved back into the terrestrial ecosystem by scavengers. These inputs comprise 34-50% of the assimilated diet of fish when carcasses are present and 7-24% via biofilm on bones after soft tissue decomposition. Our results show a terrestrial animal migration can have large impacts on a river ecosystem, which may influence nutrient cycling and river food webs at decadal time scales. Similar mass drownings may have played an important role in rivers throughout the world when large migratory herds were more common features of the landscape.
journal_name
Proc Natl Acad Sci U S Aauthors
Subalusky AL,Dutton CL,Rosi EJ,Post DMdoi
10.1073/pnas.1614778114subject
Has Abstractpub_date
2017-07-18 00:00:00pages
7647-7652issue
29eissn
0027-8424issn
1091-6490pii
1614778114journal_volume
114pub_type
杂志文章abstract::A simple method has been developed for fusing synaptic vesicles into spherical structures 20-50 micron in diameter. The method has been applied to purified cholinergic synaptic vesicles from Torpedo electric organ, and the membrane properties of these fused structures have been studied by the "cell"-attached version o...
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.85.14.5310
更新日期:1988-07-01 00:00:00
abstract::Interleukin 2 (IL-2) occupies a central position in the cascade of events involved in the immune response. We were interested in determining whether IL-2 could function as an adjuvant to vaccination, to increase the immune response to vaccine immunogens. Using the National Institutes of Health test for rabies vaccine ...
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.86.11.4240
更新日期:1989-06-01 00:00:00
abstract::Cyclic AMP (cAMP) and calcium are ubiquitous, interdependent second messengers that regulate a wide range of cellular processes. During development of neuronal networks they are critical for the first step of circuit formation, transducing signals required for axon pathfinding. Surprisingly, the spatial and temporal c...
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.1100247108
更新日期:2011-08-16 00:00:00
abstract::DNA double-strand breaks (DSBs) are serious genomic insults that can lead to chromosomal rearrangements if repaired incorrectly. To gain insight into the nuclear mechanisms contributing to these rearrangements, we developed an assay in yeast to measure cis (same site) vs. trans (different site) repair for the majority...
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.1818595116
更新日期:2019-05-07 00:00:00
abstract::We present a phylogenetic analysis to determine whether a given tRNA molecule was established in evolution before its cognate aminoacyl-tRNA synthetase. The earlier appearance of tRNA versus their metabolically related enzymes is a prediction of the RNA world theory, but the available synthetase and tRNA sequences pre...
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.95.19.11295
更新日期:1998-09-15 00:00:00
abstract::The role of protein farnesylation in lamin A biogenesis and the pathogenesis of progeria has been studied in considerable detail, but the importance of farnesylation for the B-type lamins, lamin B1 and lamin B2, has received little attention. Lamins B1 and B2 are expressed in nearly every cell type from the earliest s...
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.1303916110
更新日期:2013-05-21 00:00:00
abstract::This presentation reviews Chandra's major contribution to the understanding of nearby galaxies. After a brief summary on significant advances in characterizing various types of discrete x-ray sources, the presentation focuses on the global hot gas in and around galaxies, especially normal ones like our own. The hot ga...
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.0914255107
更新日期:2010-04-20 00:00:00
abstract::Five peptides corresponding to amino acid sequences predicted from all three reading frames of the nucleotide sequence of the third internal repeat array (IR3) of the Epstein-Barr virus (EBV) genome were synthesized chemically. All five peptides elicited antipeptide antibodies in rabbits. The antiserum raised against ...
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.81.15.4652
更新日期:1984-08-01 00:00:00
abstract::The probability of choosing an alternative in a long sequence of repeated choices is proportional to the total reward derived from that alternative, a phenomenon known as Herrnstein's matching law. This behavior is remarkably conserved across species and experimental conditions, but its underlying neural mechanisms st...
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.0505220103
更新日期:2006-10-10 00:00:00
abstract::The utilization of the isoaccepting species of leucyl-tRNA in protein synthesis has been examined in E. coli. Two minor leucyl-tRNA species, isoacceptors tRNA3Leu and tRNA4Leu, are the predominant species found bound to ribosomes during exponential growth in minimal medium. In rich medium, an increased proportion of t...
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.74.4.1393
更新日期:1977-04-01 00:00:00
abstract::The binding of bovine TSH (thyroid stimulating hormone), LH (luteinizing hormone), and their subunits to the TSH receptor of beef thyroid membranes was compared to stimulation by these agents of adenylate cyclase [ATP pyrophosphate-lyase(cyelizing), EC 4.6.1.1] in the same membranes, glucose oxidation in dog thyroid s...
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.71.9.3460
更新日期:1974-09-01 00:00:00
abstract::Oriented cell division is critical for cell fate specification, tissue organization, and tissue homeostasis, and relies on proper orientation of the mitotic spindle. The molecular mechanisms underlying the regulation of spindle orientation remain largely unknown. Herein, we identify a critical role for cylindromatosis...
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.1319341111
更新日期:2014-02-11 00:00:00
abstract::The mechanism of proton transfer from the bulk into the membrane protein interior was studied. The light-induced reduction of a bound ubiquinone molecule Q(B) by the photosynthetic reaction center is accompanied by proton trapping. We used kinetic spectroscopy to measure (i) the electron transfer to Q(B) (at 450 nm), ...
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.96.23.13159
更新日期:1999-11-09 00:00:00
abstract::Heme is a common factor linking several metabolic perturbations in Alzheimer's disease (AD), including iron metabolism, mitochondrial complex IV, heme oxygenase, and bilirubin. Therefore, we determined whether heme metabolism was altered in temporal lobes obtained at autopsy from AD patients and age-matched nondemente...
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.0404349101
更新日期:2004-07-27 00:00:00
abstract::alpha-Amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)-type glutamate receptors undergo constitutive and ligand-induced internalization that requires dynamin and the clathrin adaptor complex AP-2. We report here that an atypical basic motif within the cytoplasmic tails of AMPA-type glutamate receptors directl...
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.0611170104
更新日期:2007-02-20 00:00:00
abstract::A form of autosomal dominant juvenile myoclonic epilepsy is caused by a nonconservative missense mutation, A322D, in the GABAA receptor alpha1 subunit M3 transmembrane helix. We reported previously that the A322D mutation reduced total and surface alpha1(A322D) subunit protein and that residual alpha1(A322D) subunit 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.0700163104
更新日期:2007-08-07 00:00:00
abstract::During endoplasmic reticulum-associated degradation, the multifunctional AAA ATPase p97 is part of a protein degradation complex. p97 associates via its N-terminal domain with various cofactors to recruit ubiquitinated substrates. It also interacts with alternative substrate-processing cofactors, such as Ufd2, Ufd3, a...
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.0702966104
更新日期:2007-05-22 00:00:00
abstract::We have used a membrane-leak mass spectrometer to follow the time courses of H2 evolution and substrate reduction by nitrogenase [reduced ferredoxin:dinitrogen oxidoreductase (ATP-hydrolyzing), EC 1.18.6.1]. In the absence of added substrates, dinitrogenase passes all of its electrons to protons to form H2, but when a...
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.85.24.9446
更新日期:1988-12-01 00:00:00
abstract::Human appropriation of net primary production (HANPP), the aggregate impact of land use on biomass available each year in ecosystems, is a prominent measure of the human domination of the biosphere. We present a comprehensive assessment of global HANPP based on vegetation modeling, agricultural and forestry statistics...
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.0704243104
更新日期:2007-07-31 00:00:00
abstract::HLA-G is a nonclassical major histocompatibility complex class I (MHC-I) molecule that is primarily expressed at the fetal-maternal interface, where it is thought to play a role in protecting the fetus from the maternal immune response. HLA-G binds a limited repertoire of peptides and interacts with the inhibitory leu...
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.0409676102
更新日期:2005-03-01 00:00:00
abstract::A recently described experimental system for analyzing the mode of action of a morphogen gradient involves the in situ hybridization of sectioned tissue constructs. In these constructs, a source of activin signaling induces the transcription of several mesodermal genes in blastula animal caps, according to the positio...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章,评审
doi:10.1073/pnas.93.18.9334
更新日期:1996-09-03 00:00:00
abstract::Incubation of rat calvaria for short times in the presence of a labeled amino acid revealed the existence of a collagen fraction (procollagen) that functions as a biosynthetic precursor of collagen. Procollagen contains an alpha1-like chain (pre-alpha1) that elutes earlier from CM-cellulose than does rat-bone alpha1 a...
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.68.6.1138
更新日期:1971-06-01 00:00:00
abstract::Development of in vitro resistance to HN2 (also called mustargen or mechlorethamine hydrochloride), N,N'-bis(2-chloroethyl)-N-nitrosourea (BCNU), and cisplatin [cis-diamminedichloroplatinum(II)] was achieved in two human cell lines, the Raji/Burkitt lymphoma and a squamous cell carcinoma of the tongue. A 10- to 20-fol...
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.82.7.2158
更新日期:1985-04-01 00:00:00
abstract::Reptiles and fish have robust regenerative powers for tooth renewal. However, extant mammals can either renew their teeth one time (diphyodont dentition) or not at all (monophyodont dentition). Humans replace their milk teeth with permanent teeth and then lose their ability for tooth renewal. Here, we study tooth rene...
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.1213202110
更新日期:2013-05-28 00:00:00
abstract::We have found that phagocytic leukocytes exposed to the tumor-promoting agent, 12-O-tetradecanoyl phorbol-13-acetate, efficiently release carbon-1 of 2-deoxyglucose in the form of CO2 with concurrent intracellular accumulation of a phosphorylated 5-carbon intermediate. In the absence of 12-O-tetradecanoyl phorbol-13-a...
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.75.11.5422
更新日期:1978-11-01 00:00:00
abstract::The controlled self-assembly of complex molecules into well defined hierarchical structures is a promising route for fabricating nanostructures. These nanoscale structures can be realized by naturally occurring proteins such as tobacco mosaic virus, capsid proteins, tubulin, actin, etc. Here, we report a simple altern...
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.1730609100
更新日期:2003-09-02 00:00:00
abstract::Both neocortical and hippocampal networks organize the firing patterns of their neurons by prominent oscillations during sleep, but the functional role of these rhythms is not well understood. Here, we show a robust correlation of neuronal discharges between the somatosensory cortex and hippocampus on both slow and fi...
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.0437938100
更新日期:2003-02-18 00:00:00
abstract::Bacterial adaptation to nutrient limitation and increased population densities is central to survival and virulence. Surprisingly, <3% of Escherichia coli genes are known to play roles specific to the stationary phase. There is evidence that the leucine-responsive regulatory protein (Lrp) may play an important role 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.212510999
更新日期:2002-10-15 00:00:00
abstract::Tumor-derived adhesion factor (TAF) was previously identified as a cell adhesion molecule secreted by human bladder carcinoma cell line EJ-1. To elucidate the physiological function of TAF, we examined its distribution in human normal and tumor tissues. Immunochemical staining with an anti-TAF monoclonal antibody show...
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.93.16.8384
更新日期:1996-08-06 00:00:00
abstract::The nuclear exosome-targeting (NEXT) complex functions as an RNA exosome cofactor and is involved in surveillance and turnover of aberrant transcripts and noncoding RNAs. NEXT is a ternary complex composed of the RNA-binding protein RBM7, the scaffold zinc-knuckle protein ZCCHC8, and the helicase MTR4. While RNA inter...
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.1803530115
更新日期:2018-06-12 00:00:00