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Articles 1 - 16 of 16
Full-Text Articles in Life Sciences
Anthropomorphic Denial Of Fish Pain, Lynne U. Sneddon, Matthew C. Leach
Anthropomorphic Denial Of Fish Pain, Lynne U. Sneddon, Matthew C. Leach
Lynne Sneddon, PhD
Key (2016) affirms that we do not know how the fish brain processes pain but denies — because fish lack a human-like cortex — that fish can feel pain. He affirms that birds, like fish, have a singly-laminated cortex and that the structure of the bird brain is quite different from that of the human brain, yet he does not deny that birds can feel pain. In this commentary we describe how Key cites studies that substantiate mammalian pain but discounts the same kind of data as evidence of fish pain. We suggest that Key's interpretations are illogical, do not …
Drug-Resistant Hiv-1 Protease Regains Functional Dynamics Through Cleavage Site Coevolution, Nevra Ozer, Aysegul Ozen, Celia Schiffer, Turkan Haliloglu
Drug-Resistant Hiv-1 Protease Regains Functional Dynamics Through Cleavage Site Coevolution, Nevra Ozer, Aysegul Ozen, Celia Schiffer, Turkan Haliloglu
Celia A. Schiffer
Drug resistance is caused by mutations that change the balance of recognition favoring substrate cleavage over inhibitor binding. Here, a structural dynamics perspective of the regained wild-type functioning in mutant HIV-1 proteases with coevolution of the natural substrates is provided. The collective dynamics of mutant structures of the protease bound to p1-p6 and NC-p1 substrates are assessed using the Anisotropic Network Model (ANM). The drug-induced protease mutations perturb the mechanistically crucial hinge axes that involve key sites for substrate binding and dimerization and mainly coordinate the intrinsic dynamics. Yet with substrate coevolution, while the wild-type dynamic behavior is restored in …
Hatching Asynchrony, Survival, And The Fitness Of Alternative Adult Morphs In Ambystoma Talpoideum, Travis J. Ryan
Hatching Asynchrony, Survival, And The Fitness Of Alternative Adult Morphs In Ambystoma Talpoideum, Travis J. Ryan
Travis J. Ryan
The mole salamander, Ambystoma talpoideum, exhibits both aquatic (gilled) and terrestrial (metamorphosed) adult morphologies. Previous studies have shown the existence of body-size advantages associated with the terrestrial morph in A. talpoideum and other polymorphic salamanders (e.g., A. tigrinum). However, aquatic adult A. talpoideum mature at a younger age and often breed earlier than terrestrial adults. We tested the hypothesis that early maturation and reproduction in aquatic adults increase fitness (irrespective of body size). We reared larval A. talpoideum in mesocosms and varied the timing of hatching, with early-hatching larvae representing the offspring from early-breeding aquatic adults, and late-hatching larvae representing …
Physiological Performance Of Warm-Adapted Marine Ectotherms: Thermal Limits Of Mitochondrial Energy Transduction Efficiency, Eloy Martinez , Ph D., Eric H. Hendricks, Michael A. Menze, Joseph J. Torres
Physiological Performance Of Warm-Adapted Marine Ectotherms: Thermal Limits Of Mitochondrial Energy Transduction Efficiency, Eloy Martinez , Ph D., Eric H. Hendricks, Michael A. Menze, Joseph J. Torres
Eloy Martinez
Thermal regimes in aquatic systems have profound implications for the physiology of ectotherms. In particular, the effect of elevated temperatures on mitochondrial energy transduction (i.e. energy from carbon substrates to ATP) in tropical and subtropical teleosts may have profound consequences on organismal performance and population viability. Upper and lower whole-organism critical temperatures for teleosts suggest that subtropical and tropical species are not susceptible to the warming trends associated with climate change, but sub-lethal effects on energy transduction efficiency and population dynamics remain unclear. The goal of the present study was to compare the thermal sensitivity of processes associated with mitochondrial …
The Orientation Of Strophomenid Brachiopods On Soft Substrates, Roy Plotnick, Benjamin Dattilo, Daniel Piquard, Jennifer Bauer, Joshua Corrie
The Orientation Of Strophomenid Brachiopods On Soft Substrates, Roy Plotnick, Benjamin Dattilo, Daniel Piquard, Jennifer Bauer, Joshua Corrie
Benjamin F. Dattilo
Strophomenid brachiopods have long been interpreted as ‘‘snowshoe’’ strategists, with their flattened concavoconvex valves providing resistance to foundering in very soft sediments. There has been a sharp difference of opinion in whether the shells were oriented with their convex or their concave surface in contact with the sediment. This study, along with independent evidence from sedimentology, ichnology, and morphology, indicates that the strophomenids lived with their shells concave down (convex up). Experiments indicate the force required to push shells into soft cohesive muds is much greater for the convex up than for the convex down orientation. Forces also increase with …
Rapid Inversion: Running Animals And Robots Swing Like A Pendulum Under Ledges, Jean-Michel Mongeau, Brian Mcrae, Ardian Jusufi, Paul Birkmeyer, Aaron M. Hoover, Ronald Fearing, Robert J. Full
Rapid Inversion: Running Animals And Robots Swing Like A Pendulum Under Ledges, Jean-Michel Mongeau, Brian Mcrae, Ardian Jusufi, Paul Birkmeyer, Aaron M. Hoover, Ronald Fearing, Robert J. Full
Aaron M. Hoover
Escaping from predators often demands that animals rapidly negotiate complex environments. The smallest animals attain relatively fast speeds with high frequency leg cycling, wing flapping or body undulations, but absolute speeds are slow compared to larger animals. Instead, small animals benefit from the advantages of enhanced maneuverability in part due to scaling. Here, we report a novel behavior in small, legged runners that may facilitate their escape by disappearance from predators. We video recorded cockroaches and geckos rapidly running up an incline toward a ledge, digitized their motion and created a simple model to generalize the behavior. Both species ran …
Overwintering Energetics Of Lepidoptera: The Effects Of Winter Warming And Thermal Variability., Caroline M. Williams
Overwintering Energetics Of Lepidoptera: The Effects Of Winter Warming And Thermal Variability., Caroline M. Williams
Caroline M Williams
Winter temperatures are changing rapidly, and although winter warming reduces cold stress for overwintering ectotherms, temperature-mediated increases in metabolic rate can decrease fitness in dormant insects by increasing consumption of energy reserves. Increases in thermal variability also increase energetic demands, due to non-linear thermal response curves. My objective was to quantify the negative effects of winter warming and increases in thermal variability on a range of Lepidopteran species. As overwintering insects rely on lipid catabolism, accurate lipid measurement is central to my dissertation; so I first compared four methods of lipid quantification; concluding thin layer chromatography was the only method …
Uptake Of Dissolved Free Amino Acids By Northern Quahogs, Mercenaria Mercenaria, And Its Relative Importance To Organic Nitrogen Deposition In Narragansett Bay, Rhode Island, Michael A. Rice
Michael A Rice
Studies were undertaken to determine the relationship between size of northern quahogs Mercenaria mercenaria and the rate at which they transport aspartic acid. Quahogs ranging from 25 to 103 mm valve length were collected in Narragansett Bay and placed in seawater aquaria (27 ppt, 20 deg C) and allowed to pump actively. Uptake experiments were carried out using 1 umol/L C(14) radiolabeled aspartic acid. Aspartate transport rates in umol/h can be related to valve length by the allometric equation with a = 24.32 and b = 0.905 when valve length is in mm. In May 1990, near bottom samples of …
Food-Limited Growth And Condition Index In The Eastern Oyster, Crassostrea Virginica (Gmelin, 1791), And The Bay Scallop, Argopecten Irradians Irradians (Lamarck, 1819), Michael A. Rice, Robert B. Rheault Jr.
Food-Limited Growth And Condition Index In The Eastern Oyster, Crassostrea Virginica (Gmelin, 1791), And The Bay Scallop, Argopecten Irradians Irradians (Lamarck, 1819), Michael A. Rice, Robert B. Rheault Jr.
Michael A Rice
The growth response of the eastern oyster, Crassostrea virginica, and the bay scallop, Argopecten irradians irradians, to varying degrees of food limitation was evaluated. Under conditions of low current speed, dense assemblages of shellfish can rapidly deplete ambient food concentrations, resulting in measurable effects on growth and condition index. A flume study demonstrated significant growth and condition index responses to resource competition after reductions as small as 27% in relatively high ambient food concentrations (—4.6 u.g/1 chlorophyll). Growth rates and condition index are linearly correlated with the average chlorophyll ration consumed. A field study demonstrated similar growth responses when the …
Experimental Culture And Particle Filtration By Asian Moon Scallops, Amusium Pleuronectes, Michael A. Rice, Robert B. Rheault, Miguel S. Perez, Vicente S. Perez
Experimental Culture And Particle Filtration By Asian Moon Scallops, Amusium Pleuronectes, Michael A. Rice, Robert B. Rheault, Miguel S. Perez, Vicente S. Perez
Michael A Rice
Growth rates were determined for scallops (35-75 mm valve height) held in pocket nets and lantern nets at varying densities. The Ford-Walford linear transformation of the von Bertalanffy growth equation was used to allow quantification of food-limited stunting. Pocket nets allowed for greater growth of scallops than did the lantern nets at all stocking densities. The growth rates of scallops in pocket nets, nevertheless, were well below the growth of scallops in the wild. Clearance rates of Caribbean strains of Isochrysis galbana (C-ISO) and Chaetocerous gracilus (C-Cg) were determined for moon scallops. Amusin pleuronectes, in static chambers at 28ºC. The …
The Effects Of Copper, Cadmium And Zinc On Particle Filtration And Uptake Of Glycine In The Pacific Oyster Crassostrea Gigas, Wenyu Lin, Michael A. Rice, Paul K. Chien
The Effects Of Copper, Cadmium And Zinc On Particle Filtration And Uptake Of Glycine In The Pacific Oyster Crassostrea Gigas, Wenyu Lin, Michael A. Rice, Paul K. Chien
Michael A Rice
1. The filtration rate (volume of water completely cleared of collodial carbon per unit time) by control oysters is 36.60 ml/g hr ± 7.68 (sd).2. Filtration rates decrease with increasing concentrations of Cd2+ and Zn2+.3. In 8–16 mg/l Cu2+, filtration rates are significantly higher than the control, but in Cu2+ concentrations above 32 mg/l, filtration rates are lower than controls.4. Influx of 14C-glycine is characterized by Michaelis-Menten kinetics with Jmax and Kt values of 1.85 ± 0.097 μmol/g hr and 33.7 ± 4.6 μM respectively.5. The uptake rate of glycine from 1 μM solution is 37.79 μmol/g hr.6. In order …
Influx, Net Flux And Transepithelial Flux Of Amino Acids In The Hardshell Clam Mercenaria Mercenaria (Linne): Influence Of Salinity, Michael Rice, Grover Stephens
Influx, Net Flux And Transepithelial Flux Of Amino Acids In The Hardshell Clam Mercenaria Mercenaria (Linne): Influence Of Salinity, Michael Rice, Grover Stephens
Michael A Rice
1.1. The effects of salinity on the uptake and internal distribution of alanine and other free amino acids (FAA) in hardsell clams, Mercenaria, was studied by radiochemical and high performance liquid chromatography (HPLC) techniques.2.2. Exposure of animals to reduced salinity does not alter the rate of unidirectional alanine influx.3.3. In 34%o salinity, entry of labeled alanine reflects the net flux of the amino acid. However, in 17%o salinity, there is a net loss of alanine and other acids, mainly taurine, to the medium.4.4. Reduced salinity induces greater incorporation of radiolabeled FAA into macromolecular fractions throughout the animal.5.5. The major factors …
Influx And Transepithelial Flux Of Amino Acids In The Mussel, Mytilus Edulis., Michael A. Rice, Grover C. Stephens
Influx And Transepithelial Flux Of Amino Acids In The Mussel, Mytilus Edulis., Michael A. Rice, Grover C. Stephens
Michael A Rice
The uptake of amino acids by the non-gill epithelia of the mantle cavity of Mytilus edulis L. was studied and compared with uptake by the gills. Amino acid entry rates and the subsequent distribution of amino acids to the other tissues of the animals were studied using high-performance liquid chromatography and radiochemical techniques. Uptake via the non-gill epithelia lining the mantle cavity was separated from uptake via the gill by employing a preparation in which the gills were surgically removed. Amino acid uptake by such animals was compared with that of suitably sham-operated controls. In short-term experiments (up to 2h), …
Uptake And Internal Distribution Of Exogenously Supplied Amino Acids In The Pacific Oyster, Crassostrea Gigas (Thunberg), Michael A. Rice, Grover C. Stephens
Uptake And Internal Distribution Of Exogenously Supplied Amino Acids In The Pacific Oyster, Crassostrea Gigas (Thunberg), Michael A. Rice, Grover C. Stephens
Michael A Rice
A technique is described in which irrigation of the mantle cavity of oysters, Crassostrea gigas, induces pumping at steady rates. Simultaneous net influx of 10 amino acids (asp, glu, asn, ser, gly, tau, ala, val, phe, lys) is observed by high-performance liquid chromatography (HPLC). Individual amino acids exhibit first-order exponential depletion from an initial medium concentration of 2.0 μM. Influx of radiolabeled alanine corresponds very closely to net entry of alanine as estimated by HPLC. Therefore, net entry of alanine from dilute solution (5 μM) occurs. The entry of alanine is well described by Michaelis-Menten kinetics with a maximum influx …
Autoradiographic Localization Of Exogenously Supplied Amino Acids After Uptake By The Polychaete, Glycera Dibranchiata Ehlers, Paul Chien, Michael Rice
Autoradiographic Localization Of Exogenously Supplied Amino Acids After Uptake By The Polychaete, Glycera Dibranchiata Ehlers, Paul Chien, Michael Rice
Michael A Rice
Localization of amino acid transport sites within the integument of Glycera dibranchiata Ehlers was carried out by freeze-section and freeze-dry histological techniques. The worms were exposed for one hour to the non-metabolizable amino acid analog c(14)-cycloleucine in seawater. Freeze-sectioning and freeze drying of tissue samples allows the localization of water soluble compounds by autoradiography. Amino acid uptake is largely across the parapodial gill surfaces and the epidermis. The gills become rapidly labelled with c(14)-cycloleucine to a greater extent than the epidermal cell layers. Coelomocytes within the gills become radiolabeled in one hour. It is suggested that the rapid labelling of …
Transport Of Dissolved Amino Acids By The Mussel, Mytilus Edulis: Demonstration Of Net Uptake From Natural Seawater, Donal T. Manahan, Stephen H. Wright, Grover C. Stephens, Michael A. Rice
Transport Of Dissolved Amino Acids By The Mussel, Mytilus Edulis: Demonstration Of Net Uptake From Natural Seawater, Donal T. Manahan, Stephen H. Wright, Grover C. Stephens, Michael A. Rice
Michael A Rice
High-performance liquid chromatography provides direct evidence for substantial removal of naturally occurring specific free amino acids during a single passage of water through the mantle cavity of mussels. This occurs during the few seconds required for passage of the water across the gill, and removal proceeds unabated at ambient concentrations as low as 38 nanomoles per liter.