bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preconditioning with high mobility group box 1 (HMGB1) induces lipopolysaccharide (LPS) tolerance
Authors: Aneja Rajesh K , Tsung Allan , Sjodin Hanna , Gefter Julia V , Delude Russell L , Billiar Timothy R , Fink Mitchell P 
Published: August 2008

AbstractHigh mobility group box protein 1 (HMGB1) modulates the innate immune response when present in the extracellular compartment. Receptors for HMGB1 include TLR4, TLR2, and the receptor for advanced glycation end products (RAGE). We tested the hypothesis that extracellular HMGB1 can induce LPS tolerance. HMGB1 dose-response experiments were performed on IFN-γ-differentiated human monocyte-like THP-1 cells. Treatment with 1 μg/ml HMGB1 18 h before exposure to LPS (1 μg/ml) decreased TNF release, NF-κB nuclear DNA-binding activity, phosphorylation, and degradation of IκBα. Preconditioning with HMGB1 alone and HMGB1 in the presence of polymyxin B decreased LPS-mediated, NF-κB-dependent luciferase reporter gene expression. The specificity of HMGB1 in tolerance induction was supported further by showing that boiled HMGB1 failed to induce tolerance, and antibodies against HMGB1 blocked the induction of LPS tolerance. Bone marrow-derived macrophages obtained from C57Bl/6 wild-type mice became LPS-tolerant following HMGB1 exposure ex vivo, but macrophages derived from RAGE-deficient mice failed to develop tolerance and responded normally to LPS. Mice preconditioned with HMGB1 (20 μg) 1 h before LPS injection (10 mg/kg) had lower circulating TNF compared with control mice preconditioned with saline vehicle. Similarly, decreased nuclear DNA binding of hepatic NF-κB was observed in mice preconditioned with HMGB1. Taken together, these results suggest that extracellular HMGB1 induces LPS tolerance, and the RAGE receptor is required for this induction.
Trogocytosis and killing of IL-4-polarized monocytes by autologous NK cells
Authors: Poupot Mary , Fournié Jean-Jacques , Poupot Rémy 
Published: August 2008

AbstractCross-regulations between innate immune cells have been given more and more emphasis. Here, we address the question of bidirectional interactions between activated monocytes and autologous NK cells. Classically activated monocytes (class-monocytes), obtained by priming with IFN-γ, drive an inflammatory immune response. On the contrary, alternatively activated monocytes (alt-monocytes), obtained by stimulation with IL-4 or IL-13, engage an anti-inflammatory immune response. We show that alt-monocytes inhibit proliferation and production of IFN-γ by autologous, IL-2-activated NK cells, whereas class-monocytes do not inhibit these NK cell functions. Reciprocally, IL-2-activated NK cells interact and undertake intensive synaptic transfer with alt-monocytes, whereas interactions with class-monocytes are weaker. This strong trogocytosis correlates with an efficient killing of alt-monocytes, mediated by natural cytotoxicity receptors and a lowered killing of class-monocytes. These results suggest that interactions between NK cells and autologous-activated monocytes modulate inflammatory responses. This might be extended further in the elimination of tumor-associated macrophages, which actively promote solid tumor progression and metastasis.
Effects of dietary polyunsaturated fatty acids on mitochondrial metabolism in mammalian hibernation
Authors: Gerson Alexander R. , Brown Jason C. L. , Thomas Raymond , Bernards Mark A. , Staples James F. 
Published: August 2008

SUMMARYThirteen-lined ground squirrels (Spermophilus tridecemlineatus)were fed one of four isocaloric, isolipemic diets containing 16, 22, 35 or 55 mg linoleic acid (18:2n-6) per gram. Mitochondrial properties were compared between hibernating and summer active states, and between diet groups. As in other studies, state 3 respiration was significantly reduced in hibernation, but only in animals fed the 22 mg g–1 18:2 diet. In the other diet groups, there was no difference in state 3 respiration between the hibernating and summer active groups. In the 22 mg g–1 18:2 diet group, there was no difference in mitochondrial proton conductance between hibernating and summer active animals, again in agreement with earlier studies. However, for all other diet groups,mitochondrial proton conductance was significantly reduced during hibernation. Mitochondrial phospholipid fatty acids changed significantly with hibernation,including increases in unsaturation indices and n-6/n-3, but no differences were found among diet groups. Mitochondrial proton conductance in hibernation showed a positive correlation with the content of linoleic acid(18:2) and arachidonic acid (20:4) in mitochondrial phospholipids. Lipid peroxidation was higher in mitochondria from hibernating animals, probably due to higher unsaturation, but there was no effect of dietary 18:2 on this pattern. Despite the dietary effects on mitochondrial metabolism, all animals hibernated with no differences in bout durations, body temperatures or whole-animal metabolic rates among the diet groups. The reduced mitochondrial proton leak in the 15, 35 and 55 mg g–1 18:2 diet groups might compensate for the inability to suppress respiration, permitting whole-animal energy savings over the hibernation season.
The `upstream wake' of swimming and flying animals and its correlation with propulsive efficiency
Authors: Peng Jifeng , Dabiri John O. 
Published: August 2008

SUMMARYThe interaction between swimming and flying animals and their fluid environments generates downstream wake structures such as vortices. In most studies, the upstream flow in front of the animal is neglected. In this study,we demonstrate the existence of upstream fluid structures even though the upstream flow is quiescent or possesses a uniform incoming velocity. Using a computational model, the flow generated by a swimmer (an oscillating flexible plate) is simulated and a new fluid mechanical analysis is applied to the flow to identify the upstream fluid structures. These upstream structures show the exact portion of fluid that is going to interact with the swimmer. A mass flow rate is then defined based on the upstream structures, and a metric for propulsive efficiency is established using the mass flow rate and the kinematics of the swimmer. We propose that the unsteady mass flow rate defined by the upstream fluid structures can be used as a metric to measure and objectively compare the efficiency of locomotion in water and air.
Spiny lobsters detect conspecific blood-borne alarm cues exclusively through olfactory sensilla
Authors: Shabani Shkelzen , Kamio Michiya , Derby Charles D. 
Published: August 2008

SUMMARYWhen attacked by predators, diverse animals actively or passively release molecules that evoke alarm and related anti-predatory behavior by nearby conspecifics. The actively released molecules are alarm pheromones, whereas the passively released molecules are alarm cues. For example, many insects have alarm-signaling systems that involve active release of alarm pheromones from specialized glands and detection of these signals using specific sensors. Many crustaceans passively release alarm cues, but the nature of the cues,sensors and responses is poorly characterized. Here we show in laboratory and field experiments that injured Caribbean spiny lobsters, Panulirus argus, passively release alarm cues via blood (hemolymph) that induce alarm responses in the form of avoidance and suppression of feeding. These cues are detected exclusively through specific olfactory chemosensors,the aesthetasc sensilla. The alarm cues for Caribbean spiny lobsters are not unique to the species but do show some phylogenetic specificity: P. argus responds primarily with alarm behavior to conspecific blood, but with mixed alarm and appetitive behaviors to blood from the congener Panulirus interruptus, or with appetitive behaviors to blood from the blue crab Callinectes sapidus. This study lays the foundation for future neuroethological studies of alarm cue systems in this and other decapod crustaceans.
The ontogeny of aerobic and diving capacity in the skeletal muscles of Weddell seals
Authors: Kanatous S. B. , Hawke T. J. , Trumble S. J. , Pearson L. E. , Watson R. R. , Garry D. J. , Williams T. M. , Davis R. W. 
Published: August 2008

SUMMARYOur objective was to determine the ontogenetic changes in the skeletal muscles of Weddell seals that transform a non-diving pup into an elite diving adult. Muscle biopsies were collected from pups, juveniles and adults and analyzed for changes in fiber type, mitochondrial density, myoglobin concentrations and aerobic, lipolytic and anaerobic enzyme activities. The fiber type results demonstrated a decrease in slow-twitch oxidative (Type I)fibers and a significant increase in fast-twitch oxidative (Type IIA) fibers as the animals mature. In addition, the volume density of mitochondria and the activity of lipolytic enzymes significantly decreased as the seals matured. To our knowledge, this is the first quantitative account describing a decrease in aerobic fibers shifting towards an increase in fast-twitch oxidative fibers with a significant decrease in mitochondrial density as animals mature. These differences in the muscle physiology of Weddell seals are potentially due to their three very distinct stages of life history: non-diving pup, novice diving juvenile, and elite deep diving adult. During the first few weeks of life, pups are a non-diving terrestrial mammal that must rely on lanugo (natal fur) for thermoregulation in the harsh conditions of Antarctica. The increased aerobic capacity of pups, associated with increased mitochondrial volumes,acts to provide additional thermogenesis. As these future elite divers mature,their skeletal muscles transform to a more sedentary state in order to maintain the low levels of aerobic metabolism associated with long-duration diving.
High mitochondrial densities in the hearts of Antarctic icefishes are maintained by an increase in mitochondrial size rather than mitochondrial biogenesis
Authors: Urschel Matthew R. , O'Brien Kristin M. 
Published: August 2008

SUMMARYWe investigated the molecular mechanisms regulating differences in mitochondrial volume density between heart ventricles of Antarctic notothenioids that vary in the expression of hemoglobin (Hb) and myoglobin(Mb). In mammals, peroxisome proliferator-activated receptor γcoactivator-1α (PGC-1α) and nuclear respiratory factor 1 (NRF-1)stimulate mitochondrial biogenesis and maintain mitochondrial density in muscle tissues. We hypothesized that these factors would also maintain mitochondrial density in the hearts of Antarctic notothenioids. The percent cell volume occupied by mitochondria is significantly lower in hearts of the red-blooded notothenioid Notothenia coriiceps (18.18±0.69%) in comparison with those of the icefish Chaenocephalus aceratus(36.53±2.07%), which lacks both Hb and cardiac Mb. Mitochondrial densities are not different between hearts of N. coriiceps and Chionodraco rastrospinosus, which lacks Hb, but whose heart expresses Mb. Despite differences in mitochondrial volume density between hearts of N. coriiceps and C. aceratus, the levels of transcripts of the genes encoding PGC-1α, NRF-1 and citrate synthase, and the copy number of mitochondrial DNA do not differ. Our results indicate that the high mitochondrial densities in hearts of C. aceratus may result from an increase in organelle size. The surface-to-volume ratio of mitochondria from N. coriiceps is 1.9-fold greater than that of mitochondria from C. aceratus. In addition, the levels of PGC-1α correlate with mitochondrial density in muscle tissues of notothenioids possessing mitochondria of similar size and morphology. Finally, the levels of PGC-1α are 4.6-fold higher in the aerobic pectoral adductor muscle in comparison with the glycolytic skeletal muscle of N. coriiceps. The potential physiological significance of an increase in mitochondrial size in hearts of Antarctic icefishes is discussed.
Evidence for an apical Na–Cl cotransporter involved in ion uptake in a teleost fish
Authors: Hiroi Junya , Yasumasu Shigeki , McCormick Stephen D. , Hwang Pung-Pung , Kaneko Toyoji 
Published: August 2008

SUMMARYCation–chloride cotransporters, such as the Na+/K+/2Cl– cotransporter (NKCC) and Na+/Cl– cotransporter (NCC), are localized to the apical or basolateral plasma membranes of epithelial cells and are involved in active ion absorption or secretion. The objectives of this study were to clone and identify `freshwater-type' and `seawater-type' cation–chloride cotransporters of euryhaline Mozambique tilapia (Oreochromis mossambicus) and to determine their intracellular localization patterns within mitochondria-rich cells (MRCs). From tilapia gills, we cloned four full-length cDNAs homologous to human cation–chloride cotransporters and designated them as tilapia NKCC1a, NKCC1b, NKCC2 and NCC. Out of the four candidates, the mRNA encoding NKCC1a was highly expressed in the yolk-sac membrane and gills (sites of the MRC localization) of seawater-acclimatized fish, whereas the mRNA encoding NCC was exclusively expressed in the yolk-sac membrane and gills of freshwater-acclimatized fish. We then generated antibodies specific for tilapia NKCC1a and NCC and conducted whole-mount immunofluorescence staining for NKCC1a and NCC, together with Na+/K+-ATPase, cystic fibrosis transmembrane conductance regulator (CFTR) and Na+/H+ exchanger 3 (NHE3), on the yolk-sac membrane of tilapia embryos acclimatized to freshwater or seawater. The simultaneous quintuple-color immunofluorescence staining allowed us to classify MRCs clearly into four types: types I, II, III and IV. The NKCC1a immunoreactivity was localized to the basolateral membrane of seawater-specific type-IV MRCs, whereas the NCC immunoreactivity was restricted to the apical membrane of freshwater-specific type-II MRCs. Taking account of these data at the level of both mRNA and protein, we deduce that NKCC1a is the seawater-type cotransporter involved in ion secretion by type-IV MRCs and that NCC is the freshwater-type cotransporter involved in ion absorption by type-II MRCs. We propose a novel ion-uptake model by MRCs in freshwater that incorporates apically located NCC. We also reevaluate a traditional ion-uptake model incorporating NHE3; the mRNA was highly expressed in freshwater, and the immunoreactivity was found at the apical membrane of other freshwater-specific MRCs.
Inductive transcription and protective role of fish heme oxygenase-1 under hypoxic stress
Authors: Wang Dan , Zhong Xue-Ping , Qiao Zhi-Xian , Gui Jian-Fang 
Published: August 2008

SUMMARY
Heme oxygenase-1 is the rate-limiting enzyme in the degradation of heme into biliverdin, carbon monoxide and free divalent iron. In this study, we cloned heme oxygenase isoform 1 (CaHO-1) from a hypoxia-tolerant teleost fish Carassius auratus. The full-length cDNA of CaHO-1 is 1247 bp and encodes a protein of 272 amino acids. RT-PCR and real-time PCR analysis indicated that CaHO-1 was predominantly transcribed in posterior kidney, head kidney, gill and intestine, and induction of gene transcription was observed predominantly in posterior kidney under hypoxic stress. Moreover, the hypoxia-induced transcription was confirmed in goldfish larvae and in in vitro cultured CAB cells. Fluorescence of the HO-1-GFP fusion protein revealed a cytoplasmic and plasma membrane localization, which was consistent with the putative transmembrane structure. Subsequently, we established a stably transfected CAB/pcDNA3.1-HO-1 cell line and a control CAB/pcDNA3.1 cell line, and found that the number of dead cells was obviously reduced in the pcDNA3.1-HO-1-transfected group following 4 days of hypoxic (1% O2) treatment in comparison with numerous detached dead cells in the control pcDNA3.1-transfected cells. Furthermore, a significant cell viability difference between the two kinds of transfected cells during hypoxia–reoxygenation was revealed. Therefore,the data suggest that fish HO-1 might play a significant protective role in cells in response to hypoxic stress.
An insect trap as habitat: cohesion-failure mechanism prevents adhesion ofPameridea roridulaebugs to the sticky surface of the plantRoridula gorgonias
Authors: Voigt Dagmar , Gorb Stanislav 
Published: August 2008

SUMMARYThe glandular trichomes of the plant Roridula gorgonias release an extremely adhesive, visco-elastic, resinous secretion that traps a variety of insects, including those having a considerable body size. However, the specialized mutualistic mirid bug Pameridea roridulae lives and walks on this sticky plant surface without being trapped. We have sought to reveal the mechanism underlying the apparent non-sticky nature of the cuticle of this bug. In this study, we have visualized intact plant and insect surfaces using cryo-scanning electron microscopy and measured the adhesive properties of the plant secretion on different surfaces. We present a combination of structural and experimental results that suggest that a thick and cohesively weak film of an outermost, epicuticular greasy secretion acts as a `sloughing-off' layer,preventing the formation of contacts between the sticky plant secretion and the solid insect cuticle. In a comparative study of fresh cuticle fractures of flies representing a typical prey of R. gorgonias, a thin,fragmentary layer of epicuticular grease was revealed. These results indicate that, when trapping prey, the plant adhesive might form proper contact with solid islands of the insect cuticle that are free of epicuticular grease.
Novel surfactant proteins are involved in the structure and stability of foam nests from the frogLeptodactylus vastus
Authors: Hissa Denise Cavalcante , Vasconcelos Ilka Maria , Carvalho Ana Fontenele Urano , Nogueira Vanessa Lúcia Rodrigues , Cascon Paulo , Antunes André Saraiva Leão , de Macedo Gorete Ribeiro , Melo Vânia Maria Maciel 
Published: August 2008

SUMMARYMany amphibians lay their eggs in foam nests, which allow the eggs to be deposited out of the water. Analysis of some of these foam nests has revealed that they are a rich source of proteins with unusual primary structures and remarkable surfactant activity, named ranaspumins. The aim of this work was to study the foam nests of the frog Leptodactylus vastus in order to obtain information regarding their composition and function and to improve the understanding of ranaspumins, which are probably a novel class of surfactant proteins. Analyses of the foam fluid composition showed proteins and carbohydrates that presumably are responsible for providing nutrients for the developing tadpoles. Investigation of the function of foam fluid in chemical defence revealed no significant biological activity that could be associated with recognized defence compounds. However, foam fluid presented UV absorbance, suggesting a role in protection against sun damage, which is considered to be one of the possible causes of recently reported amphibian population declines. The foam nests do not prevent the colonization of microorganisms, such as the observed bacterial community of predominantly Gram-positive bacilli. L. vastus foam fluid shows a strong surfactant activity that was associated with their proteins and this activity seems to be due mainly to a protein named Lv-ranaspumin. This protein was isolated by ion-exchange chromatography and found to be a 20 kDa monomeric molecule with the following N-terminal sequence: FLEGFLVPKVVPGPTAALLKKALDD. This protein did not show any match to known proteins or structures, which suggests that it belongs to a new class of surfactant protein.
Phonotactic selectivity in two cryptic species of gray treefrogs: effects of differences in pulse rate, carrier frequency and playback level
Authors: Gerhardt H. Carl 
Published: August 2008

SUMMARYThe two main spectral components of the advertisement calls of two species of North American gray treefrogs (Hyla chrysoscelis and H. versicolor) overlap broadly in frequency, and the frequency of each component matches the sensitivity of one of the two different auditory inner ear organs. The calls of the two species differ in the shape and repetition rate (pulse rate) of sound pulses within trills. Standard synthetic calls with one of these spectral peaks and the pulse rate typical of conspecific calls were tested against synthetic alternatives that had the same spectral peak but a different pulse rate. The results were generalized over a wide range of playback levels. Selectivity based on differences in pulse rate depended on which spectral peak was used in some tests, and greater pulse-rate selectivity was usually observed when the low-frequency rather than the high-frequency peak was used. This effect was more pronounced and occurred over a wider range of playback levels in H. versicolor than in H. chrysosceliswhen the pulse rate of the alternative was higher than that of the standard call. In tests at high playback levels with an alternative of 15 pulses s–1, however, females of H. versicolor showed greater selectivity for the standard call when the high-frequency rather than the low-frequency spectral peak was used. This last result may reflect the different ways in which females of the two species assess trains of pulses,and the broad implications for understanding the underlying auditory mechanisms are discussed.
The role of infrequent and extraordinary deep dives in leatherback turtles (Dermochelys coriacea)
Authors: Houghton Jonathan D. R. , Doyle Thomas K. , Davenport John , Wilson Rory P. , Hays Graeme C. 
Published: August 2008

SUMMARY
Infrequent and exceptional behaviours can provide insight into the ecology and physiology of a particular species. Here we examined extraordinarily deep(300–1250 m) and protracted (&gt;1h) dives made by critically endangered leatherback turtles (Dermochelys coriacea) in the context of three previously suggested hypotheses: predator evasion, thermoregulation and exploration for gelatinous prey. Data were obtained via satellite relay data loggers attached to adult turtles at nesting beaches(N=11) and temperate foraging grounds (N=2), constituting a combined tracking period of 9.6 years (N=26,146 dives) and spanning the entire North Atlantic Ocean. Of the dives, 99.6% (N=26,051) were to depths &lt;300 m with only 0.4% (N=95) extending to greater depths(subsequently termed `deep dives'). Analysis suggested that deep dives: (1)were normally distributed around midday; (2) may exceed the inferred aerobic dive limit for the species; (3) displayed slow vertical descent rates and protracted durations; (4) were much deeper than the thermocline; and (5)occurred predominantly during transit, yet ceased once seasonal residence on foraging grounds began. These findings support the hypothesis that deep dives are periodically employed to survey the water column for diurnally descending gelatinous prey. If a suitable patch is encountered then the turtle may cease transit and remain within that area, waiting for prey to approach the surface at night. If unsuccessful, then migration may continue until a more suitable site is encountered. Additional studies using a meta-analytical approach are nonetheless recommended to further resolve this matter.