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Full-Text Articles in Life Sciences

Quantitative Trait Loci Mapping Reveals Candidate Pathways Regulating Cell Cycle Duration In Plasmodium Falciparum, Heather B. Reilly Ayala, Mark A. Wacker, Geoffrey Siwo, Michael T. Ferdig Oct 2010

Quantitative Trait Loci Mapping Reveals Candidate Pathways Regulating Cell Cycle Duration In Plasmodium Falciparum, Heather B. Reilly Ayala, Mark A. Wacker, Geoffrey Siwo, Michael T. Ferdig

Faculty Publications - Department of Biological & Molecular Science

Background: Elevated parasite biomass in the human red blood cells can lead to increased malaria morbidity. The genes and mechanisms regulating growth and development of Plasmodium falciparum through its erythrocytic cycle are not well understood. We previously showed that strains HB3 and Dd2 diverge in their proliferation rates, and here use quantitative trait loci mapping in 34 progeny from a cross between these parent clones along with integrative bioinformatics to identify genetic loci and candidate genes that control divergences in cell cycle duration. Results: Genetic mapping of cell cycle duration revealed a four-locus genetic model, including a major genetic effect …


Inhibition Of Nonsense-Mediated Mrna Decay By Antisense Morpholino Oligonucleotides Restores Functional Expression Of Herg Nonsense And Frameshift Mutations In Long-Qt Syndrome, Qiuming Gong, Matthew R. Stump, Zhengfeng Zhou Jan 2010

Inhibition Of Nonsense-Mediated Mrna Decay By Antisense Morpholino Oligonucleotides Restores Functional Expression Of Herg Nonsense And Frameshift Mutations In Long-Qt Syndrome, Qiuming Gong, Matthew R. Stump, Zhengfeng Zhou

Faculty Publications - Department of Biological & Molecular Science

Mutations in the human ether-a-go-go-related gene (hERG) cause long-QT syndrome type 2 (LQT2). We previously described a homozygous LQT2 nonsense mutation Q1070X in which the mutant mRNA is degraded by nonsense-mediated mRNA decay (NMD) leading to a severe clinical phenotype. The degradation of the Q1070X transcript precludes the expression of truncated but functional mutant channels. In the present study, we tested the hypothesis that inhibition of NMD can restore functional expression of LQT2 mutations that are targeted by NMD. We showed that inhibition of NMD by RNA interference-mediated knockdown of UPF1 increased Q1070X mutant channel protein expression and hERG current …


Mitochondrial Physiology Of Diapausing And Developing Embryos Of The Annual Killifsh Austrofundulus Limnaeus: Implications For Extreme Anoxia Tolerance, Jeff Duerr, Jason E. Podrabsky Jan 2010

Mitochondrial Physiology Of Diapausing And Developing Embryos Of The Annual Killifsh Austrofundulus Limnaeus: Implications For Extreme Anoxia Tolerance, Jeff Duerr, Jason E. Podrabsky

Faculty Publications - Department of Biological & Molecular Science

Diapausing embryos of the annual killiWsh Austrofundulus limnaeus have the highest reported anoxia tolerance of any vertebrate and previous studies indicate modified mitochondrial physiology likely supports anoxic metabolism. Functional mitochondria isolated from diapausing and developing embryos of the annual killifish exhibited VO2, respiratory control ratios (RCR), and P:O ratios consistent with those obtained from other ectothermic vertebrate species. Reduced oxygen consumption associated with dormancy in whole animal respiration rates are correlated with maximal respiration rates of mitochondria isolated from diapausing versus developing embryos. P:O ratios for developing embryos were similar to those obtained from adult liver, but were diminished in …


Effects Of Flight Speed Upon Muscle Activity In Hummingbirds, Bret W. Tobalske, Andrew A. Biewener, Douglas R. Warrick, Tyson L. Hedrick, Donald R. Powers Jan 2010

Effects Of Flight Speed Upon Muscle Activity In Hummingbirds, Bret W. Tobalske, Andrew A. Biewener, Douglas R. Warrick, Tyson L. Hedrick, Donald R. Powers

Faculty Publications - Department of Biological & Molecular Science

Hummingbirds have the smallest body size and highest wingbeat frequencies of all flying vertebrates, so they represent one endpoint for evaluating the effects of body size on sustained muscle function and flight performance. Other bird species vary neuromuscular recruitment and contractile behavior to accomplish flight over a wide range of speeds, typically exhibiting a Ushaped curve with maxima at the slowest and fastest flight speeds. To test whether the high wingbeat frequencies and aerodynamically active upstroke of hummingbirds lead to different patterns, we flew rufous hummingbirds (Selasphorus rufus, 3􀀃g body mass, 42􀀃Hz wingbeat frequency) in a variable-speed wind tunnel (0–10􀀃m􀀃s–1). …


Erk Activation And Cell Growth Require Cam Kinases In Mcf-7 Breast Cancer Cells, John M. Schmitt, Ellen Abell, Andrea Wagner, Monika A. Davare Jan 2010

Erk Activation And Cell Growth Require Cam Kinases In Mcf-7 Breast Cancer Cells, John M. Schmitt, Ellen Abell, Andrea Wagner, Monika A. Davare

Faculty Publications - Department of Biological & Molecular Science

Previous studies on MCF-7 breast cancer cells have shown that the G-protein coupled receptor (GPCR) agonist carbachol increases intracellular calcium levels and the activation of extracellular signal-regulated kinase (ERK). Calcium and calmodulin regulate the calcium/calmodulin- dependent kinase (CaM kinase) family of proteins that have been proposed to regulate ERK and gene transcription. Our results suggest that both estrogen (E2) and carbachol treatment of MCF-7 breast cancer cells trigger phosphorylation of ERK I /2 and the transcription factor Elk-1. Carbachol and estrogen triggered nearly a four- to sixfold increase in MCF-7 cell proliferation by 96 h, respectively. Carbachol-stimulated ERK activation and …


Arthropod Foraging By A Southeastern Arizona Hummingbird Guild, Don Powers, Jessamyn A. Van Hook, Elizabeth A. Sandlin, Todd J. Mcwhorter Jan 2010

Arthropod Foraging By A Southeastern Arizona Hummingbird Guild, Don Powers, Jessamyn A. Van Hook, Elizabeth A. Sandlin, Todd J. Mcwhorter

Faculty Publications - Department of Biological & Molecular Science

We tested the hypothesis that foraging for arthropods may be a viable source of energy when hummingbirds are competitively excluded from sources of nectar. We hypothesized that the Magnificent Hummingbird (Eugenes fulgens) relies more upon arthropods than the Blue-throated Hummingbird (Lampornis clemenciae) or Blackchinned Hummingbird (Archilochus alexandri) in southeastern Arizona. We were unable to quantify arthropod foraging by A. alexandri, but measured frequent arthropod foraging by both E. fulgens and L. clemenciae. E. fulgens engaged in more aerial flycatching than L. clemenciae, and their rate of flycatching attempts was higher than by L. clemenciae. Analysis of gut contents showed that …


Alternative Splicing And Polyadenylation Contribute To The Generation Of Herg1 C-Terminal Isoforms, Qiuming Gong, Matthew R. Stump, A. Russell Dunn, Vivianne Deng, Zhengfeng Zhou Jan 2010

Alternative Splicing And Polyadenylation Contribute To The Generation Of Herg1 C-Terminal Isoforms, Qiuming Gong, Matthew R. Stump, A. Russell Dunn, Vivianne Deng, Zhengfeng Zhou

Faculty Publications - Department of Biological & Molecular Science

The human ether-a-go-go-related gene 1 (hERG1) encodes the pore-forming subunit of the rapidly activating delayed rectifier potassium channel. Several hERG1 isoforms with different N- and C-terminal ends have been identified. The hERG1a, hERG1b, and hERG1-3.1 isoforms contain the full-length C terminus, whereas the hERG1USOisoforms, hERG1aUSO and hERG1bUSO, lack most of the C-terminal domain and contain a unique C-terminal end. The mechanisms underlying the generation of hERG1USOisoforms are not understood. We show that hERG1 isoforms with different C-terminal ends are generated by alternative splicing and polyadenylation of hERG1 pre-mRNA. We identified an …


Mutational Studies Uncover Non-Native Structure In The Dimeric Kinetic Intermediate Of The H2a–H2b Heterodimer, Matthew R. Stump, Lisa M. Gloss Jan 2010

Mutational Studies Uncover Non-Native Structure In The Dimeric Kinetic Intermediate Of The H2a–H2b Heterodimer, Matthew R. Stump, Lisa M. Gloss

Faculty Publications - Department of Biological & Molecular Science

The folding pathway of the histone H2A–H2B heterodimer minimally includes an on-pathway, dimeric, burst-phase intermediate, I2. The partially folded H2A and H2B monomers populated at equilibrium were characterized as potential monomeric kinetic intermediates. Folding kinetics were compared for initiation from isolated, folded monomers and the heterodimer unfolded in 4 M urea. The observed rates were virtually identical above 0.4Murea, exhibiting a log-linear relationship on the final denaturant concentration. Below ∼0.4 M urea (concentrations inaccessible from the 4-M urea unfolded state), a rollover in the rates was observed; this suggests that a component of the I2 ensemble contains non-native structure that …