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911.
Surface-based underwater videography with submeter-accuracy differential GPS is a method with several advantages, including high spatial and visual resolution, effectiveness at all depths at which seagrasses occur, non-destructive sampling, and rapid data collection in the field. Here I investigate the statistical power of this method applied to a natural meadow and to virtual meadows created by a spatially explicit model of seagrass disturbance, regrowth, and colonization. The approach is found to detect a 5–10% loss in short timespans at 80% probability, with a sampling design emphasizing long transects (≅400 m or greater) and a paired analysis in which the same permanent transects are followed each monitoring event. A field effort function shows that this precision is possible within a single working field day for sampling regions ≅1 km2. These conclusions hold regardless of the presence of positional error in remonitoring previous transects by submeter DGPS navigation. 相似文献
912.
Hsu LJ Hong Q Schultz L Kuo E Lin SR Lee MH Lin YS Chang NS 《Cellular signalling》2008,20(7):1303-1312
Zfra is a small size 31-amino-acid C2H2 zinc finger-like protein, which is known to interact with c-Jun N-terminal kinase 1 (JNK1), WW domain-containing oxidoreductase (WWOX, FOR or WOX1), TNF receptor-associated death domain protein (TRADD) and nuclear factor kappaB (NF-kappaB) during stress response. Here, we show that Zfra became phosphorylated at Ser8 (as determined by specific antibody) and translocated to the mitochondria in response to inducers of mitochondrial permeability transition (MPT) (e.g. staurosporine and betulinic acid). Overexpressed Zfra induced cell death. This event is associated, in part, with increased dissipation of mitochondrial membrane potential (MMP) and increased chromosomal DNA fragmentation. Intriguingly, Zfra significantly downregulated Bcl-2 and yet blocked cytochrome c release from the mitochondria. Overexpression of an S8G-Zfra mutant (Ser8 to Gly8 alteration) could not induce cell death, probably due to its failure of translocating to the mitochondria and causing MMP dissipation. Over-expressed proapoptotic WOX1 induced cytochrome c release from the mitochondria. Zfra bound and blocked the effect of WOX1. Taken together, Ser8 is essential for overexpressed Zfra to exert cell death via the mitochondrial pathway. Zfra downregulates Bcl-2 and induces MMP dissipation but causes no cytochrome c release, indicating a novel death pathway from the mitochondria. 相似文献
913.
914.
Kato N Sakata T Breton G Le Roch KG Nagle A Andersen C Bursulaya B Henson K Johnson J Kumar KA Marr F Mason D McNamara C Plouffe D Ramachandran V Spooner M Tuntland T Zhou Y Peters EC Chatterjee A Schultz PG Ward GE Gray N Harper J Winzeler EA 《Nature chemical biology》2008,4(6):347-356
Calcium-dependent protein kinases play a crucial role in intracellular calcium signaling in plants, some algae and protozoa. In Plasmodium falciparum, calcium-dependent protein kinase 1 (PfCDPK1) is expressed during schizogony in the erythrocytic stage as well as in the sporozoite stage. It is coexpressed with genes that encode the parasite motor complex, a cellular component required for parasite invasion of host cells, parasite motility and potentially cytokinesis. A targeted gene-disruption approach demonstrated that pfcdpk1 seems to be essential for parasite viability. An in vitro biochemical screen using recombinant PfCDPK1 against a library of 20,000 compounds resulted in the identification of a series of structurally related 2,6,9-trisubstituted purines. Compound treatment caused sudden developmental arrest at the late schizont stage in P. falciparum and a large reduction in intracellular parasites in Toxoplasma gondii, which suggests a possible role for PfCDPK1 in regulation of parasite motility during egress and invasion. 相似文献
915.
Wolf M Ruderisch B Dandekar T Schultz J Müller T 《Bioinformatics (Oxford, England)》2008,24(20):2401-2402
MOTIVATION: The Profile Neighbor Joining (PNJ) algorithm as implemented in the software ProfDist is computationally efficient in reconstructing very large trees. Besides the huge amount of sequence data the structure is important in RNA alignment analysis and phylogenetic reconstruction. RESULTS: For this ProfDistS provides a phylogenetic workflow that uses individual RNA secondary structures in reconstructing phylogenies based on sequence-structure alignments-using PNJ with manual or iterative and automatic profile definition. Moreover, ProfDistS can deal also with protein sequences. 相似文献
916.
Morten Grunnet Rie Schultz Hansen Sren-Peter Olesen 《Progress in biophysics and molecular biology》2008,98(2-3):347
The cardiac action potential is the result of an orchestrated function of a number of different ion channels. Action potential repolarisation in humans relies on three potassium current components named IKr, IKs and IK1 with party overlapping functions. The ion channel α-subunits conducting these currents are hERG1 (Kv11.1), KCNQ1 (Kv7.1) and Kir2.1. Loss-of-function in any of these currents can result in long QT syndrome. Long QT is a pro-arrhythmic disease with increased risk of developing lethal ventricular arrhythmias such as Torsade de Pointes and ventricular fibrillation. In addition to congenital long QT, acquired long QT can also constitute a safety risk. Especially unintended inhibition of the hERG1 channel constitutes a major concern in the development of new drugs. Based on this knowledge is has been speculated whether activation of the hERG1 channel could be anti-arrhythmic and thereby constitute a new principle in treatment of cardiac arrhythmogenic disorders. The first hERG1 channel agonist was reported in 2005 and a limited number of such compounds are now available. In the present text we review results obtained by hERG1 channel activation in a number of cardiac relevant settings from in vitro to in vivo. It is demonstrated how the principle of hERG1 channel activation under certain circumstances can constitute a new anti-arrhythmogenic principle. Finally, important conceptual differences between the short QT syndrome and the hERG1 channel activation, are evaluated. 相似文献
917.
Yu-Long Li Yanfeng Ding Chad Agnew Harold D Schultz 《Journal of applied physiology》2008,105(3):782-790
An enhancement of peripheral chemoreflex sensitivity contributes to sympathetic hyperactivity in chronic heart failure (CHF) rabbits. The enhanced chemoreflex function in CHF involves augmented carotid body (CB) chemoreceptor activity via upregulation of the angiotensin II (ANG II) type 1 (AT(1))-receptor pathway and downregulation of the neuronal nitric oxide synthase (nNOS)-nitric oxide (NO) pathway in the CB. Here we investigated whether exercise training (EXT) normalizes the enhanced peripheral chemoreflex function in CHF rabbits and possible mechanisms mediating this effect. EXT partially, but not fully, normalized the exaggerated baseline renal sympathetic nerve activity (RSNA) and the response of RSNA to hypoxia in CHF rabbits. EXT also decreased the baseline CB nerve single-fiber discharge (4.9 +/- 0.4 vs. 7.7 +/- 0.4 imp/s at Po(2) = 103 +/- 2.3 Torr) and the response to hypoxia (20.6 +/- 1.1 vs. 36.3 +/- 1.3 imp/s at Po(2) = 41 +/- 2.2 Torr) from CB chemoreceptors in CHF rabbits, which could be reversed by treatment of the CB with ANG II or a nNOS inhibitor. Our results also showed that NO concentration and protein expression of nNOS were increased in the CBs from EXT + CHF rabbits, compared with that in CHF rabbits. On the other hand, elevated ANG II concentration and AT(1)-receptor overexpression of the CBs in CHF state were blunted by EXT. These results indicate that EXT normalizes the CB chemoreflex in CHF by preventing an increase in afferent CB chemoreceptor activity. EXT reverses the alterations in the nNOS-NO and ANG II-AT(1)-receptor pathways in the CB responsible for chemoreceptor sensitization in CHF. 相似文献
918.
Ulrich G. Mueller Heather D. Ishak Sofia M. Bruschi Chad C. Smith Jacob J. Herman Scott E. Solomon Alexander S. Mikheyev Christian Rabeling Jarrod J. Scott Michael Cooper Andre Rodrigues Adriana Ortiz Carlos R. F. Brandão John E. Lattke Fernando C. Pagnocca Stephen A. Rehner Ted R. Schultz Heraldo L. Vasconcelos Rachelle M. M. Adams Martin Bollazzi Rebecca M. Clark Anna G. Himler John S. LaPolla Inara R. Leal Robert A. Johnson Flavio Roces Jeffrey Sosa‐Calvo Rainer Wirth Maurício Bacci Jr 《Molecular ecology》2017,26(24):6921-6937
Leafcutter ants propagate co‐evolving fungi for food. The nearly 50 species of leafcutter ants (Atta, Acromyrmex) range from Argentina to the United States, with the greatest species diversity in southern South America. We elucidate the biogeography of fungi cultivated by leafcutter ants using DNA sequence and microsatellite‐marker analyses of 474 cultivars collected across the leafcutter range. Fungal cultivars belong to two clades (Clade‐A and Clade‐B). The dominant and widespread Clade‐A cultivars form three genotype clusters, with their relative prevalence corresponding to southern South America, northern South America, Central and North America. Admixture between Clade‐A populations supports genetic exchange within a single species, Leucocoprinus gongylophorus. Some leafcutter species that cut grass as fungicultural substrate are specialized to cultivate Clade‐B fungi, whereas leafcutters preferring dicot plants appear specialized on Clade‐A fungi. Cultivar sharing between sympatric leafcutter species occurs frequently such that cultivars of Atta are not distinct from those of Acromyrmex. Leafcutters specialized on Clade‐B fungi occur only in South America. Diversity of Clade‐A fungi is greatest in South America, but minimal in Central and North America. Maximum cultivar diversity in South America is predicted by the Kusnezov–Fowler hypothesis that leafcutter ants originated in subtropical South America and only dicot‐specialized leafcutter ants migrated out of South America, but the cultivar diversity becomes also compatible with a recently proposed hypothesis of a Central American origin by postulating that leafcutter ants acquired novel cultivars many times from other nonleafcutter fungus‐growing ants during their migrations from Central America across South America. We evaluate these biogeographic hypotheses in the light of estimated dates for the origins of leafcutter ants and their cultivars. 相似文献
919.
Native insect herbivory overwhelms context dependence to limit complex invasion dynamics of exotic weeds
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Emily L. Schultz James O. Eckberg Sergey S. Berg Svata M. Louda Tom E. X. Miller 《Ecology letters》2017,20(11):1374-1384
Understanding the role of consumers in density‐dependent plant population dynamics is a long‐standing goal in ecology. However, the generality of herbivory effects across heterogeneous landscapes is poorly understood due to the pervasive influence of context‐dependence. We tested effects of native insect herbivory on the population dynamics of an exotic thistle, Cirsium vulgare, in a field experiment replicated across eight sites in eastern Nebraska. Using hierarchical Bayesian analysis and density‐dependent population models, we found potential for explosive low‐density population growth (λ > 5) and complex density fluctuations under herbivore exclusion. However, herbivore access drove population decline (λ < 1), suppressing complex fluctuations. While plant–herbivore interaction outcomes are famously context‐dependent, we demonstrated that herbivores suppress potentially invasive populations throughout our study region, and this qualitative outcome is insensitive to environmental context. Our novel use of Bayesian demographic modelling shows that native insect herbivores consistently prevent hard‐to‐predict fluctuations of weeds in environments otherwise susceptible to invasion. 相似文献
920.
The Gene Mutated in Variant Late-Infantile Neuronal Ceroid Lipofuscinosis (CLN6) and in nclf Mutant Mice Encodes a Novel Predicted Transmembrane Protein
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Ruth B. Wheeler Julie D. Sharp Roger A. Schultz John M. Joslin Ruth E. Williams Sara E. Mole 《American journal of human genetics》2002,70(2):537-542
The neuronal ceroid lipofuscinoses (NCLs) are a group of autosomal recessive neurodegenerative diseases characterized by the accumulation of autofluorescent lipopigment in various tissues and by progressive cell death in the brain and retina. The gene for variant late-infantile NCL (vLINCL), CLN6, was previously mapped to chromosome 15q21-23 and is predicted to be orthologous to the genes underlying NCL in nclf mice and in South Hampshire and Merino sheep. The gene underlying this disease has been identified with six different mutations found in affected patients and with a 1-bp insertion in the orthologous Cln6 gene in the nclf mouse. CLN6 encodes a novel 311-amino acid protein with seven predicted transmembrane domains, is conserved across vertebrates and has no homologies with proteins of known function. One vLINCL mutation, affecting a conserved amino acid residue within the predicted third hydrophilic loop of the protein, has been identified, suggesting that this domain may play an important functional role. 相似文献