bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hypotonicity induced K+ and anion conductive pathways activation in eel intestinal epithelium
Authors: Lionetto M. G. , Giordano M. E. , De Nuccio F. , Nicolardi G. , Hoffmann E. K. , Schettino T. 
Published: February 2005

SUMMARYControl of cell volume is a fundamental and highly conserved physiological mechanism, essential for survival under varying environmental and metabolic conditions. Epithelia (such as intestine, renal tubule, gallbladder and gills)are tissues physiologically exposed to osmotic stress. Therefore, the activation of `emergency' systems of rapid cell volume regulation is fundamental in their physiology. The aim of the present work was to study the physiological response to hypotonic stress in a salt-transporting epithelium,the intestine of the euryhaline teleost Anguilla anguilla. Eel intestinal epithelium, when symmetrically bathed with Ringer solution,develops a net Cl- current giving rise to a negative transepithelial potential at the basolateral side of the epithelium.The eel intestinal epithelium responded to a hypotonic challenge with a biphasic decrease in the transepithelial voltage (Vte) and the short circuit current (Isc). This electrophysiological response correlated with a regulatory volume decrease (RVD) response, recorded by morphometrical measurement of the epithelium height. Changes in the transepithelial resistance were also observed following the hypotonicity exposure.The electrogenic Vte and Iscresponses to hypotonicity resulted from the activation of different K+ and anion conductive pathways on the apical and basolateral membranes of the epithelium: (a) iberiotoxin-sensitive K+ channels on the apical and basolateral membrane, (b) apamin-sensitive K+channels mainly on the basolateral membrane, (c) DIDS-sensitive anion channels on the apical membrane. The functional integrity of the basal Cl-conductive pathway on the basolateral membrane is also required.The electrophysiological response to hypotonic stress was completely abolished by Ca2+ removal from the Ringer perfusing solution, but was not affected by depletion of intracellular Ca2+ stores by thapsigargin.
Effects of physiological state, mass change and diet on plasma metabolite profiles in the western sandpiperCalidris mauri
Authors: Seaman D. A. , Guglielmo C. G. , Williams T. D. 
Published: February 2005

SUMMARYWe used a food restriction/refeeding protocol to put birds through a controlled cycle of mass loss and mass gain to investigate the effects of rate and phase of mass change on plasma metabolite levels in relation to diet. Despite marked differences in fat content of the two diets (18% vs4%) mean rate of mass loss or mass gain was independent of diet. There was also no effect of diet on plasma levels of any of the four measured metabolite(triglyceride, glycerol, uric acid and β-OH-butyrate) during mass loss. However, during mass gain birds on the low fat diet had higher plasma levels of triglyceride and uric acid and lower β-OH-butyrate than birds gaining mass on the high-fat diet. Thus, diet composition can affect plasma metabolite profiles independently of differences in rates of mass change. Nevertheless,certain plasma metabolites were related to variation in rates of mass change across physiological states. Glycerol levels were negatively related to the rate of mass change (independent of diet), and butyrate was negatively related to the rate of mass change on both diets (though the slope of this relationship was diet dependent). Uric acid was positively related to the rate of mass change but only for birds on the low-fat diet. Our study therefore confirms that measurement of plasma metabolites can provide robust information on physiological state (gain, loss) and the rate of mass change (e.g. in free-living birds caught only once) although researchers should be cogniscent of potential confounding effects of diet composition for certain metabolites,both for field studies and for future experimental validations of this technique.
Eyeshine and spectral tuning of long wavelength-sensitive rhodopsins: no evidence for red-sensitive photoreceptors among five Nymphalini butterfly species
Authors: Briscoe Adriana D. , Bernard Gary D. 
Published: February 2005

SUMMARYSpectral tuning of rhodopsins commonly refers to the effects of opsin amino acid substitutions on the wavelength for peak sensitivity of the rhodopsin absorption spectrum. Nymphalini butterflies provide an opportunity for identifying some of the amino acid substitutions responsible for insect rhodopsin spectral tuning because the majority of photoreceptor cells (R3-9)in the adult retina express only a single long wavelength-sensitive (LWS)opsin mRNA transcript. Therefore, the opsin genotype can be directly correlated with its phenotype. We determined the LWS opsin gene sequence from cDNA of the mourning cloak Nymphalis antiopa, and from genomic DNA of the malachite Siproeta stelenes and the peacock Inachis io.Using an epi-microspectrophotometer we examined each butterfly's eyeshine for photochemical evidence of multiple LWS rhodopsins and found only one. We then performed partial-bleaching experiments to obtain absorbance spectra for the LWS rhodopsins of all three species as well as from another nymphalid, the buckeye Junonia coenia. The isolated LWS opsin gene sequences varied in length from 1437-1612 bp and encode rhodopsins R522 (S. stelenes),R530 (I. io), R534 (N. antiopa) and, together with a previously published sequence, R510 (J. coenia). Comparative sequence analysis indicates that the S. stelenes rhodopsin is slightly blue-shifted compared to the typical 530 nm lepidopteran rhodopsin because of the presence of a S138A substitution at a homologous site that in mammalian MWS/LWS rhodopsins causes a 5 nm blue-shift. The difference in peak absorption between R522 of S. stelenes and R530 of Inachis io is therefore largely accounted for by this substitution. This suggests that spectral tuning mechanisms employing the S138A may have evolved in parallel in mammalian and butterfly MWS/LWS rhodopsins across 500 million years of evolution.
Challenges and intriguing problems in comparative renal physiology
Authors: Dantzler William H. 
Published: February 2005

SUMMARYThe comparative approach has proved important many times in understanding renal function and continues to offer possible approaches to unsolved problems today, in three general areas.Quantification of glomerular ultrafiltration. In contrast to the complex capillary network in the mammalian glomerulus, the glomerulus of the superficial loopless (reptilian-type) avian nephrons consists of a single capillary loop. This structure, in an avian species where it can be approached directly, should for the first time permit accurate determinations of the pressure profiles and the capillary area involved in glomerular ultrafiltration in an animal with high arterial pressure. Fluid reabsorption by proximal renal tubules. In some reptilian proximal renal tubules, isolated and perfused in vitro, isosmotic fluid reabsorption can occur at control rates when lithium replaces sodium or when some other substance replaces sodium or chloride or both in the perfusate and bathing medium simultaneously. Reabsorption at the control rates, regardless of the composition of the perfusate and bathing medium, can be at least partially inhibited by cold and cyanide, but not by blockers of Na+-K+-ATPase. It is also independent of the buffer system used, but it is reduced about 20% by removal of colloid from the peritubular fluid. During the substitutions, the surface area of the proximal tubule cells increases dramatically and might permit some insignificant force to be more effective in the reabsorptive process. Understanding the process involved in this, apparently unique coupling of solute and fluid transport,certainly would be very valuable in understanding coupled transport of solutes and water across epithelia in general. Urate secretion by proximal renal tubules. Urate is the major excretory end product of nitrogen metabolism in birds, most reptiles, and a few amphibians. It undergoes net secretion by the renal tubules. It has been possible to learn much about the physiology of net secretion in reptiles and birds and this process appears to be similar to the much less significant secretory flux in some mammals. However, nothing is known about the molecular basis of the transport system and understanding these processes may provide important information for mammals as well as reptiles and birds. These are some examples of intriguing possibilities for comparative studies of renal physiology.
Olfactory learning by means of trophallaxis inApis mellifera
Authors: Gil Mariana , De Marco Rodrigo J. 
Published: February 2005

SUMMARYEarly reports indicate that trophallaxis, i.e. the exchange of liquid food by mouth, may allow honeybees to assign nectar odours with predictive values to anticipate biological meaningful reward stimuli. Nevertheless, this type of learning has not been addressed directly. In the present study, pairs of animals were isolated to induce trophallaxis under controlled conditions and,afterwards, the honeybee proboscis extension reflex was used to investigate the possible role of trophallaxis in learning olfactory cues. The results demonstrate unambiguously that associative learning actually occurs by means of trophallaxis. Animals associate the odour (as the conditioned stimulus or CS) and the sucrose (as the unconditioned stimulus or US) present in the solution they receive through trophallaxis. Moreover, this particular kind of learning leads to long-term olfactory memories after a single learning trial,even when trophallaxis is brief. In addition, we found that the strength of association is clearly affected by CS and US intensity as well as the recent previous foraging experiences of the animals. Comparisons are presented among several features of the learning during trophallaxis and the classical conditioning of the proboscis extension reflex with restrained subjects. Finally, the relevance of learning through trophallaxis in the task of successful foraging is discussed.
Thyroglobulin Antibodies in Serum of Patients with Differentiated Thyroid Cancer: Relationship between Epitope Specificities and Thyroglobulin Recovery
Authors: Okosieme Onyebuchi E , Evans Carol , Moss Laura , Parkes Arthur B , Premawardhana LD Kuvera E , Lazarus John H 
Published: February 2005

Abstract
Background: Serum antibodies against thyroglobulin (TgAbs) are common in patients with differentiated thyroid cancer (DTC) and can interfere in thyroglobulin (Tg) assays. We identified the epitopes on Tg recognized by TgAb-positive sera from patients with DTC and examined the association between epitope specificity patterns and Tg recovery.
Methods: We tested 50 DTC sera for Tg epitope specificity, TgAbs, and Tg recovery. Epitope recognition was determined by use of a panel of 10 well-characterized Tg monoclonal antibodies directed against 6 Tg antigenic clusters (I–VI) in competitive reactions with test sera. Tg was measured by the Thyroglobuline IRMA (CIS bio international). Recovery of added Tg (TgREC) was determined by an in-house assay.
Results: Epitope recognition was restricted to immunodominant clusters in 58% of patients, whereas the rest were either broadly heterogeneous (16%) or nonreactive (26%). Median Tg recovery did not differ between sera with restricted and unrestricted specificities (69% vs 80%; P &gt;0.05). TgREC was inversely correlated with the total number of epitopes recognized by sera (r = −0.66; P &lt;0.001).
Conclusions: TgAbs with both restricted and broad specificities are present in patients with DTC. TgAb interference is related to the number of epitopes recognized by sera rather than the pattern of epitope recognition.
Analysis of T-Cell Receptor Vβ Gene Repertoires after Immune Stimulation and in Malignancy by Use of Padlock Probes and Microarrays
Authors: Banér Johan , Marits Per , Nilsson Mats , Winqvist Ola , Landegren Ulf 
Published: February 2005

Abstract
Background: Detection of expanded T-cell clones, identified by their receptor (TCR) repertoires, can assist diagnosis and guide therapy in infectious, inflammatory, and autoimmune conditions as well as in tumor immunotherapy. Analysis of tumor-infiltrating lymphocytes often reveals preferential use of one or a few TCR Vβ genes, compared with peripheral blood, indicative of a clonal response against tumor antigens.
Methods: To simultaneously measure the relative expression of all Vβ gene families, we combined highly specific and sensitive oligonucleotide reagents, called padlock probes, with a microarray read-out format. T-Cell cDNA was combined with a pool of Vβ subfamily-specific padlock probes. Reacted probes were selectively amplified and the products hybridized to a microarray, from which the Vβ subfamily distribution in each sample could be determined relative to a control sample.
Results: In lymphocytes stimulated with the superantigen staphylococcal enterotoxin B, we detected expansions at the mRNA level of TCR subfamilies previously shown to respond to staphylococcal enterotoxin B. Expansions of the same Vβ families could also be detected by flow cytometry. In samples from two bladder cancer patients, we detected predominant representations of specific Vβ subfamilies in both tumor-infiltrating lymphocytes and in the draining lymph nodes, but not in non-tumor-draining lymph nodes or peripheral blood. Several expression profiles from draining lymph nodes in patients with malignant melanoma were divergent from profiles seen in non-tumor-draining lymph nodes.
Conclusion: Padlock probe-based parallel analysis of TCR Vβ gene distributions provides an efficient method for screening multiple samples for T-cell clonal expansions with reduced labor and time of analysis compared with traditional methods.
The structure of the juvenile hormone binding protein gene from Galleria mellonella
Authors: Sok Agnieszka J. , Czajewska Kamila , Ożyhar Andrzej , Kochman Marian 
Published: February 2005

AbstractJuvenile hormone (JH) and ecdysone are the key hormones controlling insect growth and development. The juvenile hormone binding protein (JHBP) is the first member in the array of proteins participating in JH signal transmission. In the present report a wholejhbpgene sequence (9790 bp) is described. Thejhbpgene contains four introns (A–D). All the introns have common flanking sequences: GT at the 5′ and AG at the 3′ end. The first intron is in phase 1, the second in phase 2, and the third and fourth in phase 1. An analysis of these sequences suggests that U2-class spliceosomes are involved in intron excision from pre-mRNA. Several horizontally transmitted elements from other genes were found in the introns. Alljhbpexons are positioned in local AT-reach regions of the gene. A search for core promoter regulatory elements revealed that the TATA box starts 29 bp preceding the start of transcription; the sequence TCAGTA representing a putative initiator sequence (Inr) starts at position +14. Eight characteristic sequences for bindingBroad-Complexgene products, which coordinate the ecdysone temporal response, are present in the non-coding sequence of thejhbpgene. An analysis of exon locations and intron phases indicates thatjhbpgene organization is related to theretinol binding proteingene, a member of the lipocalin family.
Interaction of thiamin diphosphate with phosphorylated and dephosphorylated mammalian pyruvate dehydrogenase complex
Authors: Liu Xiaoqing , Bisswanger Hans 
Published: February 2005

AbstractKinetic and binding studies were carried out on substrate and cofactor interaction with the pyruvate dehydrogenase complex from bovine heart. Fluoropyruvate and pyruvamide, previously described as irreversible and allosteric inhibitors, respectively, are strong competitive inhibitors with respect to pyruvate. Binding of thiamin diphosphate was used to study differences between the active dephosphorylated and inactive phosphorylated enzyme states by spectroscopic methods. The change in both the intrinsic tryptophan fluorescence and the fluorescence of the 6-bromoacetyl-2-dimethylaminonaphthalene-labelled enzyme complex produced on addition of the cofactor showed similar binding behaviour for both enzyme forms, with slightly higher affinity for the phosphorylated form. Changes in the CD spectrum, especially the negative Cotton effect at 330 nm as a function of cofactor concentration, both in the absence and presence of pyruvate, also revealed no drastic differences between the two enzyme forms. Thus, inactivation of the enzyme activity of the pyruvate dehydrogenase complex is not caused by impeding the binding of substrate or cofactor.
Characterization of the glyoxalases of the malarial parasite Plasmodium falciparum and comparison with their human counterparts
Authors: Akoachere Monique , Iozef Rimma , Rahlfs Stefan , Deponte Marcel , Mannervik Bengt , Creighton Donald J. , Schirmer Heiner , Becker Katja 
Published: February 2005

AbstractThe glyoxalase system consisting of glyoxalase I (GloI) and glyoxalase II (GloII) constitutes a glutathione-dependent intracellular pathway converting toxic 2-oxoaldehydes, such as methylglyoxal, to the corresponding 2-hydroxyacids. Here we describe a complete glyoxalase system in the malarial parasitePlasmodium falciparum. The biochemical, kinetic and structural properties of cytosolic GloI (cGloI) and two GloIIs (cytosolic GloII named cGloII, and tGloII preceded by a targeting sequence) were directly compared with the respective isofunctional host enzymes. cGloI and cGloII exhibit lowerKmvalues and higher catalytic efficiencies (kcat/Km) than the human counterparts, pointing to the importance of the system in malarial parasites. A Tyr185Phe mutant of cGloII shows a 2.5-fold increase inKm, proving the contribution of Tyr185 to substrate binding. Molecular models suggest very similar active sites/metal binding sites of parasite and host cell enzymes. However, a fourth protein, which has highest similarities to GloI, was found to be unique for malarial parasites; it is likely to act in the apicoplast, and has as yet undefined substrate specificity. Various S-(N-hydroxy-N-arylcarbamoyl)glutathiones tested asP. falciparumGlo inhibitors were active in the lower nanomolar range. The Glo system ofPlasmodiumwill be further evaluated as a target for the development of antimalarial drugs.
Piezoresistive Scanning Proximity Probes for Nanoscience (Piezoresistive Raster-Kraftsonden für die Nanowissenschaften)
Authors: Rangelow Iwo W. 
Published: February 2005

Abstract
This article is devoted to the realization of piezoresistive sensors used in scanning probe microscopy. It is expected that in the near future major technological breakthroughs in scanning proximal probe nanotools will allow for key scientific impact on analysis and synthesis of nanostructures. All the piezoresistive cantilever sensors described here are based on advanced silicon micromachining and standard CMOS processing. Moreover, using a newly optimized piezoresistive detection scheme process comprising a Wheatstone bridge, we have designed and fabricated piezoresistive cantilevers for atomic force microscopy, which improve surface topography resolution by an order of magnitude to 0.1 nm. The elegance of this concept is that by using an almost identical detection principle and differently functionalized tips or cantilever surfaces, we can detect subtle sample interactions (mechanical, electrical, thermal, and chemical) with a significantly more compact system than with optical beam deflection techniques. For noncontact scanning force microscopy, we integrate a thermally driven bimorph actuator with the piezoresistive cantilever and make use of direct-oscillation in a higher flexural mode. The cantilever then operates in the phase-shift atomic force microscopy (AFM) detection technique.
Thermomechanische Einflüsse der Chipklebung auf die Genauigkeit mikromechanischer Drucksensoren Teil 2: Experimentelle Verifikation (Thermomechanical Effects of the Adhesive Die Attachment on the Accuracy of MEMS Pressure Sensors)
Authors: Deier Erik , Hoyden Jens , Wilde Jürgen , Becker Klaus 
Published: February 2005

Abstract
Thermomechanische Belastungen können die Funktionalität mikromechanischer Sensoren stark beeinflussen. Im ersten Teil dieser Arbeit wurde das thermomechanische Verhalten geklebter Drucksensoren mit der Finite-Elemente-Methode simuliert. In diesem Teil werden Prüfungen zur Verifikation der Simulationsergebnisse vorgestellt. Dazu werden die Messergebnisse zu den Kennlinien verschieden aufgebauter Drucksensoren unter Betriebsbedingungen vorgestellt. Insbesondere der Einfluss von Druck und Temperatur wird für die untersuchten Sensorkonfigurationen ausgewertet.
Fehlerkorrektur piezoresistiver Drucksensoren mit optimierter Kalibrierung des Signalwandlers (Error Correction of Piezoresistive Pressure Sensors by Optimised Signal Conditioner Calibration)
Authors: Wohlgemuth Christian , Lotz Peter , Werthschützky Roland 
Published: February 2005

Abstract
Für die mikrocontrollerbasierte Fehlerkorrektur von piezoresistiven Drucksensoren ist eine aufwändige messtechnische Erfassung des Sensorkennfeldes notwendig. Mithilfe einer optimierten Messstrategie und unter Verwendung von typischen Werten der Sensorcharge kann die Anzahl der durchzuführenden Messungen deutlich gesenkt werden.
Piezoresistive Chemosensoren auf der Basis von Hydrogelen (Piezoresistive Chemical Sensors Based on Hydrogels)
Authors: Günther Margarita , Sorber Jörg , Gerlach Gerald , Suchaneck Gunnar , Thong Thrinh Quang , Arndt Karl-Friedrich , Richter Andreas 
Published: February 2005

Abstract
Hydrogele zeigen in Abhängigkeit von der sie umgebenden Flüssigkeit ein starkes Quellungsvermögen. Dies kann für die Schaffung chemischer Sensoren, z.B. für die Messung des pH-Wertes, ausgenutzt werden. Dafür lassen sich piezoresistive Sensoren nutzen, wobei das quellende Hydrogel zu einer Verformung der Silizium-Biegeplatte des Sensorchips führt. Es wurden die Ausgangsspannung in Abhängigkeit vom pH-Wert untersucht und die für eine hohe Signalreproduzierbarkeit erforderlichen Messbedingungen ermittelt.
A Threefold Genetic Allee Effect
Authors: Willi Yvonne , Van Buskirk Josh , Fischer Markus 
Published: February 2005

Abstract
A decline in population size can lead to the loss of allelic variation, increased inbreeding, and the accumulation of genetic load through drift. We estimated the fitness consequences of these processes in offspring of controlled within-population crosses from 13 populations of the self-incompatible, clonal plant Ranunculus reptans. We used allozyme allelic richness as a proxy for long-term population size, which was positively correlated with current population size. Crosses between plants of smaller populations were less likely to be compatible. Inbreeding load, assessed as the slope of the relationship between offspring performance and parental kinship coefficients, was not related to population size, suggesting that deleterious mutations had not been purged from small populations. Offspring from smaller populations were on average more inbred, so inbreeding depression in clonal fitness was higher in small populations. We estimated variation in drift load from the mean fitness of outbred offspring and found enhanced drift load affecting female fertility within small populations. We conclude that self-incompatibility systems do not necessarily prevent small populations from suffering from inbreeding depression and drift load and may exacerbate the challenge of finding suitable mates.