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Full-Text Articles in Life Sciences

Beyond The Kármán Gait: Knifefish Swimming In Periodic And Irregular Vortex Streets, Victor M. Ortega-Jiménez, Christopher P. Sanford May 2021

Beyond The Kármán Gait: Knifefish Swimming In Periodic And Irregular Vortex Streets, Victor M. Ortega-Jiménez, Christopher P. Sanford

Faculty and Research Publications

Neotropical freshwater fishes such as knifefishes are commonly faced with navigating intense and highly unsteady streams. However, our knowledge on locomotion in apteronotids comes from laminar flows, where the ribbon fin dominates over the pectoral fins or body bending. Here, we studied the 3D kinematics and swimming control of seven black ghost knifefish (Apteronotus albifrons) moving in laminar flows (flow speed U∞≈1-5 BL s-1) and in periodic vortex streets (U∞≈2-4 BL s-1). Two different cylinders (∼2 and ∼3 cm diameter) were used to generate the latter. Additionally, fish were exposed to an irregular wake produced by a free oscillating cylinder …


Effects Of Hypoxia On Swimming And Sensing In A Weakly Electric Fish, Kerri Lynn Ackerly, Rüdiger Krahe, Christopher P. Sanford, Lauren J. Chapman May 2018

Effects Of Hypoxia On Swimming And Sensing In A Weakly Electric Fish, Kerri Lynn Ackerly, Rüdiger Krahe, Christopher P. Sanford, Lauren J. Chapman

Faculty and Research Publications

Low dissolved oxygen (hypoxia) can severely limit fish performance, especially aerobically expensive behaviours including swimming and acquisition of sensory information. Fishes can reduce oxygen requirements by altering these behaviours under hypoxia, but the underlying mechanisms can be difficult to quantify. We used a weakly electric fish as a model system to explore potential effects of hypoxia on swim performance and sensory information acquisition, which enabled us to non-invasively record electric signalling activity used for active acquisition of sensory information during swimming. To quantify potential effects of hypoxia, we measured critical swim speed (Ucrit) and concurrent electric signalling activity under highand …


Breaking In And Busting Out: Cell-Penetrating Peptides And The Endosomal Escape Problem, Julia C. Lecher, Scott J. Nowak, Jonathan Mcmurry Aug 2017

Breaking In And Busting Out: Cell-Penetrating Peptides And The Endosomal Escape Problem, Julia C. Lecher, Scott J. Nowak, Jonathan Mcmurry

Faculty and Research Publications

Cell-penetrating peptides (CPPs) have long held great promise for the manipulation of living cells for therapeutic and research purposes. They allow a wide array of biomolecules from large, oligomeric proteins to nucleic acids and small molecules to rapidly and efficiently traverse cytoplasmic membranes. With few exceptions, if a molecule can be associated with a CPP, it can be delivered into a cell. However, a growing realization in the field is that CPP-cargo fusions largely remain trapped in endosomes and are eventually targeted for degradation or recycling rather than released into the cytoplasm or trafficked to a desired subcellular destination. This …


Functional Diversity Of Small And Large Trees Along Secondary Succession In A Tropical Dry Forest, Lucía Sanaphre-Villanueva, Juan Manuel Dupuy, José Luis Andrade, Casandra Reyes-García, Horacio Paz, Paula C. Jackson Jul 2016

Functional Diversity Of Small And Large Trees Along Secondary Succession In A Tropical Dry Forest, Lucía Sanaphre-Villanueva, Juan Manuel Dupuy, José Luis Andrade, Casandra Reyes-García, Horacio Paz, Paula C. Jackson

Faculty and Research Publications

Functional Diversity is considered an important driver of community assembly in environmental and successional gradients. To understand tree assembly processes in a semideciduous tropical forest, we analyzed the variation of Functional Richness (FRic), Functional Divergence (FDiv), and Functional Evenness (FEve) of small vs. large trees in relation to fallow age after slash-and-burn agriculture and topographical position (flat sites vs. hills). FRic of small trees was lower than null model predicted values across the successional gradient, and decreased unexpectedly in older successional ages. FRic of large trees was higher than null model predictions early in succession and lower in late-successional stands …


Novel Cell Penetrating Peptide-Adaptors Effect Intracellular Delivery And Endosomal Escape Of Protein Cargos, John C. Salerno, Verra M. Ngwa, Scott J. Nowak, Carol A. Chrestensen, Allison N. Healey, Jonathan L. Mcmurry Jan 2016

Novel Cell Penetrating Peptide-Adaptors Effect Intracellular Delivery And Endosomal Escape Of Protein Cargos, John C. Salerno, Verra M. Ngwa, Scott J. Nowak, Carol A. Chrestensen, Allison N. Healey, Jonathan L. Mcmurry

Faculty and Research Publications

The use of cell penetrating peptides (CPPs) as biomolecular delivery vehicles holds great promise for therapeutic and other applications, but development has been stymied by poor delivery and lack of endosomal escape. We have developed a CPP-adaptor system capable of efficient intracellular delivery and endosomal escape of user-defined protein cargos. The cell penetrating sequence of HIV transactivator of transcription was fused to calmodulin, which binds with subnanomolar affinity to proteins containing a calmodulin binding site. Our strategy has tremendous advantage over prior CPP technologies because it utilizes high affinity noncovalent, but reversible coupling between CPP and cargo. Three different cargo …


Handedness For Unimanual Grasping In 564 Great Apes: The Effect On Grip Morphology And A Comparison With Hand Use For A Bimanual Coordinated Task, Adrien Meguerditchian, Kimberley A. Phillips, Amandine Chapelain, Lindsay M. Mahovetz, Scott Milne, Tara Stoinski, Amanda Bania, Elizabeth Lonsdorf, Jennifer Schaeffer, Jamie Russell, William D. Hopkins Nov 2015

Handedness For Unimanual Grasping In 564 Great Apes: The Effect On Grip Morphology And A Comparison With Hand Use For A Bimanual Coordinated Task, Adrien Meguerditchian, Kimberley A. Phillips, Amandine Chapelain, Lindsay M. Mahovetz, Scott Milne, Tara Stoinski, Amanda Bania, Elizabeth Lonsdorf, Jennifer Schaeffer, Jamie Russell, William D. Hopkins

Faculty and Research Publications

A number of factors have been proposed to influence within and between species variation in handedness in non-human primates. In the initial study, we assessed the influence of grip morphology on hand use for simple reaching in a sample of 564 great apes including 49 orangutans Pongo pygmaeus, 66 gorillas Gorilla gorilla, 354 chimpanzees Pan troglodytes and 95 bonobos Pan paniscus. Overall, we found a significant right hand bias for reaching. We also found a significant effect of the grip morphology of hand use. Grasping with the thumb and index finger was more prevalent in the right compared to left …


Akirin Links Twist-Regulated Transcription With The Brahma Chromatin Remodeling Complex During Embryogenesis, Scott J. Nowak, Hitoshi Aihara, Katie Gonzalez, Yutaka Nibu, Mary K. Baylies Mar 2012

Akirin Links Twist-Regulated Transcription With The Brahma Chromatin Remodeling Complex During Embryogenesis, Scott J. Nowak, Hitoshi Aihara, Katie Gonzalez, Yutaka Nibu, Mary K. Baylies

Faculty and Research Publications

The activities of developmentally critical transcription factors are regulated via interactions with cofactors. Such interactions influence transcription factor activity either directly through protein–protein interactions or indirectly by altering the local chromatin environment. Using a yeast double-interaction screen, we identified a highly conserved nuclear protein, Akirin, as a novel cofactor of the key Drosophila melanogaster mesoderm and muscle transcription factor Twist. We find that Akirin interacts genetically and physically with Twist to facilitate expression of some, but not all, Twist-regulated genes during embryonic myogenesis. akirin mutant embryos have muscle defects consistent with altered regulation of a subset of Twistregulated genes. To …


A Genome Triplication Associated With Early Diversification Of The Core Eudiocts, Yuannian Jiao, Jim Leebens-Mack, Saravanaraj Ayyampalayam, Joel Mcnearl Jan 2012

A Genome Triplication Associated With Early Diversification Of The Core Eudiocts, Yuannian Jiao, Jim Leebens-Mack, Saravanaraj Ayyampalayam, Joel Mcnearl

Faculty and Research Publications

Background: Although it is agreed that a major polyploidy event, gamma, occurred within the eudicots, the phylogenetic placement of the event remains unclear. Results: To determine when this polyploidization occurred relative to speciation events in angiosperm history, we employed a phylogenomic approach to investigate the timing of gene set duplications located on syntenic gamma blocks. We populated 769 putative gene families with large sets of homologs obtained from public transcriptomes of basal angiosperms, magnoliids, asterids, and more than 91.8 gigabases of new next-generation transcriptome sequences of non-grass monocots and basal eudicots. The overwhelming majority (95%) of wellresolved gamma duplications was …


Electrosensory Ampullary Organs Are Derived From Lateral Line Placodes In Bony Fishes, Melissa S. Modrell, William E. Benis, R. Glenn Northcutt, Marcus C. Davis, Clare V.H. Baker Oct 2011

Electrosensory Ampullary Organs Are Derived From Lateral Line Placodes In Bony Fishes, Melissa S. Modrell, William E. Benis, R. Glenn Northcutt, Marcus C. Davis, Clare V.H. Baker

Faculty and Research Publications

Electroreception is an ancient subdivision of the lateral line sensory system, found in all major vertebrate groups (though lost in frogs, amniotes and most ray-finned fishes). Electroreception is mediated by 'hair cells' in ampullary organs, distributed in fields flanking lines of mechanosensory hair cell-containing neuromasts that detect local water movement. Neuromasts, and afferent neurons for both neuromasts and ampullary organs, develop from lateral line placodes. Although ampullary organs in the axolotl (a representative of the lobe-finned clade of bony fishes) are lateral line placode-derived, non-placodal origins have been proposed for electroreceptors in other taxa. Here we show morphological and molecular …


Cortical Representation Of Lateralized Grasping In Chimpanzees (Pan Troglodytes): A Combined Mri And Pet Study, William D. Hopkins, Jared P. Taglialatela, Jamie L. Russell, Talia M. Nir, Jennifer Schaeffer Oct 2010

Cortical Representation Of Lateralized Grasping In Chimpanzees (Pan Troglodytes): A Combined Mri And Pet Study, William D. Hopkins, Jared P. Taglialatela, Jamie L. Russell, Talia M. Nir, Jennifer Schaeffer

Faculty and Research Publications

Functional imaging studies in humans have localized the motor-hand region to a neuroanatomical landmark call the KNOB within the precentral gyrus. It has also been reported that the KNOB is larger in the hemisphere contralateral to an individual's preferred hand, and therefore may represent the neural substrate for handedness. The KNOB has also been neuronatomically described in chimpanzees and other great apes and is similarly associated with handedness. However, whether the chimpanzee KNOB represents the hand region is unclear from the extant literature. Here, we used PET to quantify neural metabolic activity in chimpanzees when engaged in unilateral reach-and-grasping responses …


The Effect Of Road Crossing On Fish Movements In Small Etowah Basin Streams, Paul D. Benton, William E. Ensign, Byron J. Freeman Jan 2008

The Effect Of Road Crossing On Fish Movements In Small Etowah Basin Streams, Paul D. Benton, William E. Ensign, Byron J. Freeman

Faculty and Research Publications

Increased road construction associated with urbanization may result in fragmentation and loss offish populations in streams. In this study, we documented frequency of movement of fishes through three separate types of road-crossings (clear-span bridges, box culverts, and tube culverts) in six small streams using mark-recapture sampling. Upstream movement between areas separated by either box or tube culverts was lower than upstream movement between similar areas not separated by a road crossing. Downstream movement between areas separated by box culverts was also lower than downstream movement between areas without obstructions. Upstream and downstream movement between areas separated by clear-span bridges was …


Investigating Hydrologic Alteration As A Mechanism Of Fish Assemblage Shifts In Urbanizing Streams, Allison H. Roy, Mary C. Freeman, Byron J. Freeman, Seth J. Wenger, William E. Ensign, Judith L. Meyer Sep 2005

Investigating Hydrologic Alteration As A Mechanism Of Fish Assemblage Shifts In Urbanizing Streams, Allison H. Roy, Mary C. Freeman, Byron J. Freeman, Seth J. Wenger, William E. Ensign, Judith L. Meyer

Faculty and Research Publications

Stream biota in urban and suburban settings are thought to be impaired by altered hydrology; however, it is unknown what aspects of the hydrograph alter fish assemblage structure and which fishes are most vulnerable to hydrologic alterations in small streams. We quantified hydrologic variables and fish assemblages in 30 small streams and their subcatchments (area 8-20 km 2) in the Etowah River Catchment (Georgia, USA). We stratified streams and their subcatchments into 3 landcover categories based on imperviousness (20% of subcatchment), and then estimated the degree of hydrologic alteration based on synoptic measurements of baseflow yield. We derived hydrologic variables …


Behavioral Evidence For Chemosensory And Thermosensory Pathway Convergence In The Caenorhabditis Elegans Nervous System, Bowman O. Davis Jr., Lewis Vanbrackle, Darren Pittard Jan 2002

Behavioral Evidence For Chemosensory And Thermosensory Pathway Convergence In The Caenorhabditis Elegans Nervous System, Bowman O. Davis Jr., Lewis Vanbrackle, Darren Pittard

Faculty and Research Publications

The nematode, Caenorhabditis elegans, is an established model system to explore the ways simple nervous systems detect and direct organismal responses to environmental changes. C. elegans possesses specialized receptor cells for the detection of a variety of environmental stimuli. Separate cell types respond to volatile chemical and thermal stimuli and the neural pathways for these show anatomical evidence of convergence. This work reports findings from behavioral assays during simultaneous exposure of nematodes to both thermal differences and attractant volatile chemicals. Combined exposure to benzaldehyde and cold neutralized the behavioral responses to both stimuli in 24°C acclimated worms. Diacetyl and mild …