bluuebunny/crossref_metadata_2025_split huggingface dataset:
Limited extracellular but complete intracellular acid-base regulation during short-term environmental hypercapnia in the armoured catfish,Liposarcus pardalis
Authors: Brauner C. J. , Wang T. , Wang Y. , Richards J. G. , Gonzalez R. J. , Bernier N. J. , Xi W. , Patrick M. , Val A. L. 
Published: August 2004

SUMMARYEnvironmental hypercapnia induces a respiratory acidosis that is usually compensated within 24-96 h in freshwater fish. Water ionic composition has a large influence on both the rate and degree of pH recovery during hypercapnia. Waters of the Amazon are characteristically dilute in ions, which may have consequences for acid-base regulation during environmental hypercapnia in endemic fishes. The armoured catfish Liposarcus pardalis, from the Amazon, was exposed to a water PCO2 of 7, 14 or 42 mmHg in soft water (in μmol l-1: Na+, 15,Cl-, 16, K+, 9, Ca2+, 9, Mg2+, 2). Blood pH fell within 2 h from a normocapnic value of 7.90±0.03 to 7.56±0.04, 7.34±0.05 and 6.99±0.02, respectively. Only minor extracellular pH (pHe) recovery was observed in the subsequent 24-96 h. Despite the pronounced extracellular acidosis,intracellular pH (pHi) of the heart, liver and white muscle was tightly regulated within 6 h (the earliest time at which these parameters were measured) via a rapid accumulation of intracellular HCO3-. While most fish regulate pHi during exposure to environmental hypercapnia, the time course for this is usually similar to that for pHe regulation. The degree of extracellular acidosis tolerated by L. pardalis, and the ability to regulate pHi in the face of an extracellular acidosis, are the greatest reported to date in a teleost fish. The preferential regulation of pHi in the face of a largely uncompensated extracellular acidosis in L. pardalis is rare among vertebrates, and it is not known whether this is associated with the ability to air-breathe and tolerate aerial exposure, or living in water dilute in counter ions, or with other environmental or evolutionary selective pressures. The ubiquity of this strategy among Amazonian fishes and the mechanisms employed by L. pardalis are clearly worthy of further study.
Characterization ofFxr1inDanio rerio; a simple vertebrate model to study costamere development
Authors: Engels Bart , van 't Padje Sandra , Blonden Lau , Severijnen Lies-anne , Oostra Ben A. , Willemsen Rob 
Published: August 2004

SUMMARYThe X-linked FMR1 gene, which is involved in the fragile X syndrome, forms a small gene family with its two autosomal homologs, FXR1 and FXR2. Mouse models for the FXR genes have been generated and proved to be valuable in elucidating the function of these genes, particularly in adult mice. Unfortunately, Fxr1 knockout mice die shortly after birth, necessitating an animal model that allows the study of the role of Fxr1p, the gene product of Fxr1, in early embryonic development. For gene function studies during early embryonic development the use of zebrafish as a model organism is highly advantageous.In this paper the suitability of the zebrafish as a model organism to study Fxr1p function during early development is explored. As a first step, we present here the initial characterization of Fxr1p in zebrafish. Fxr1p is present in all the cells from zebrafish embryos from the 2/4-cell stage onward; however, during late development a more tissue-specific distribution is found, with the highest expression in developing muscle. In adult zebrafish, Fxr1p is localized at the myoseptum and in costamere-like granules in skeletal muscle. In the testis, Fxr1p is localized in immature spermatogenic cells and in brain tissue Fxr1p displays a predominantly nuclear staining in neurons throughout the brain. Finally, the different tissue-specific isoforms of Fxr1p are characterized.Since the functional domains and the expression pattern of Fxr1p in zebrafish are comparable to those in higher vertebrates such as mouse and human, we conclude that the zebrafish is a highly suitable model for functional studies of Fxr1p.
Cadmium-induced apoptosis in oyster hemocytes involves disturbance of cellular energy balance but no mitochondrial permeability transition
Authors: Sokolova I. M. , Evans S. , Hughes F. M. 
Published: August 2004

SUMMARYExposure to environmentally prevalent heavy metals such as cadmium can have detrimental effects on a variety of commercially and ecologically important species such as oysters. Since Cd2+ is known to induce apoptosis in immune cells of vertebrates, we have investigated the effects of this metal on isolated oyster hemocytes, the main cellular immune defense in mollusks. Enhanced apoptosis of these cells could conceivably create immunosuppressed conditions in these organisms and result in reduced disease resistance and increased opportunistic infection, resulting in decline of their populations. Cd2+ exposure induced apoptosis in oyster hemocytes in a dose-dependent manner in the range of 10-100 μmol l-1, as indicated by the translocation of phosphatidylserine to the outer leaflet of the plasma membrane. At higher concentrations (200-1000 μmol l-1), there was no further increase in apoptosis but a significant increase in the level of necrosis. In stark contrast to vertebrate immune cells, there was no decrease in the mitochondrial membrane potential or activation of caspases in response to Cd2+ in the apoptotic range. Surprisingly, Cd2+ exposure in this range did cause a significant decrease in intracellular ATP levels, indicating a severe disturbance of energy metabolism. Similarly, Cd2+ exposure of isolated mitochondria resulted in partial uncoupling of mitochondria but no difference in mitochondrial membrane potential. The results demonstrate that the important environmental pollutant Cd2+ induces apoptosis in oyster immune cells and does so through a mitochondria/caspase-independent pathway,suggesting that a novel, perhaps ancient, apoptotic pathway is active in these cells. Furthermore, it appears that the observed decrease in ATP production during apoptosis is not due to the loss of the mitochondrial proton-motive force but is more likely to be due to inhibition of the F0/F1-ATPase and/or mitochondrial ADP/ATP or substrate transport.
Grouping of visual objects by honeybees
Authors: Zhang Shaowu , Srinivasan Mandyam V. , Zhu Hong , Wong Jason 
Published: August 2004

SUMMARYRecent work has revealed that monkeys as well as pigeons are able to categorise complex visual objects. We show here that the ability to group similar, natural, visual images together extends to an invertebrate - the honeybee. Bees can be trained to distinguish between different types of naturally occurring scenes in a rather general way, and to group them into four distinct categories: landscapes, plant stems and two different kinds of flowers. They exhibit the same response to novel visual objects that differ greatly in their individual, low-level features, but belong to one of the four categories. We exclude the possibility that they might be using single,low-level features as a cue to categorise these natural visual images and suggest that the categorisation is based on a combination of low-level features and configurational cues.
A conserved domain of alkaline phosphatase expression in the Malpighian tubules of dipteran insects
Authors: Cabrero Pablo , Pollock Valerie P. , Davies Shireen A. , Dow Julian A. T. 
Published: August 2004

SUMMARYMalpighian (renal) tubules are key components of the insect osmoregulatory system and show correspondingly great diversity in both number and length. Recently, the organisation of the Drosophila melanogaster tubule has been elucidated by enhancer trapping, and an array for functional properties has been shown to align with the functional domains. In Drosophila,there is a lower tubule domain, which coincides with expression of alkaline phosphatase and delineates the absorptive region of the tubule. Here, these observations are extended to three dipteran vectors of disease (Aedes aegypti, Anopheles stephensii and Glossina morsitans) and a non-dipteran out-group, Schistocerca gregaria (Orthoptera). Despite a huge range in cell number and size, alkaline phosphatase was found on the apical surface of the lower 10% of each of the dipteran tubules but nowhere within the orthopteran tubule. An alkaline phosphatase lower tubule domain is thus conserved among Diptera.Cell counts are also provided for each species. As in Drosophila,stellate cells are not found in the lower tubule domain of Anophelesor Aedes tubules, confirming the unique genetic identity of this domain. As previously reported, we failed to find stellate cells in Schistocerca but, remarkably, also failed to find them in Glossina, the dipteran most closely related to Drosophila. The orthodoxy that stellate cells are unique to, and general among, Diptera may thus require revision.
Structural basis for control of secondary vessels in the long-finned eel Anguilla reinhardtii
Authors: Skov Peter Vilhelm , Bennett Michael Brian 
Published: August 2004

SUMMARY
Histological sections of primary segmental arteries and associated interarterial anastomoses and secondary vessels from the long-finned eel Anguilla reinhardtii were examined by light and transmission electron microscopy. Interarterial anastomoses were found to originate from the primary vasculature as depressions through the tunica intima and media, from where they ran perpendicularly to the adventitial layer, before coiling extensively. From here the anastomoses travelled a relatively linear path in the outer margin of the adventitia to anastomose with a secondary vessel running in parallel with the primary counterpart. In contrast to findings from other species, secondary vessels had a structure quite similar to that of primary vessels; they were lined by endothelial cells on a continuous basement membrane, with a single layer of smooth muscle cells surrounding the vessel. Smooth muscle cells were also found in the vicinity of interarterial anastomoses in the adventitia, but these appeared more longitudinally orientated. The presence of smooth muscle cells on all aspects of the secondary circulation suggests that this vascular system is regulated in a similar manner as the primary vascular system. Because interarterial anastomoses are structurally integrated with the primary vessel from which they originate, it is anticipated that flow through secondary vessels to some extent is affected by the vascular tone of the primary vessel. Immunohistochemical studies showed that primary segmental arteries displayed moderate immunoreactivity to antibodies against 5-hydroxytryptamine and substance P, while interarterial anastomoses and secondary vessels showed dense immunoreactivity. No immunoreactivity was observed on primary or secondary arteries against neuropeptide Y or calcitonin gene-related peptide.
The 14-3-3 proteins in the teleost fish rainbow trout (Oncorhynchus mykiss)
Authors: Koskinen Heikki , Krasnov Aleksei , Rexroad Caird , Gorodilov Yuri , Afanasyev Sergey , Mölsä Hannu 
Published: August 2004

SUMMARY
We report studies of 14-3-3 genes in rainbow trout, adding to current understanding of the molecular evolution of this multigene family and its functional importance in fish. Ten genes were identified that are apparent duplicates of five ancestors. The duplicated 14-3-3 genes diverged rapidly and their cladogram is markedly different from the phylogenetic tree. The mean rate of nonsynonymous divergence of trout 14-3-3 genes is one order of magnitude greater than that of mammalian genes. An evolutionarily recent genome duplication in salmonid fish relaxed functional constraints, and selection favored establishment of novel isoforms. Differences in tissue distribution of 14-3-3 genes were minor; however, results of 31 microarray experiments showed divergence of expression profiles, which was related to structural divergence of the duplicates. We observed remarkable coordination of expression of all isoforms in our study of stress response in the brain. Profiles of the 14-3-3 genes correlated with a large group of chaperones and genes involved in cell communication and signal transduction. We studied embryonic expression of 14-3-3 genes and found abundant transcripts in the rapidly growing and differentiating parts of embryos such as eyes, tail bud and yolk syncytium during somitogenesis and in gills and pectoral fins after completion of somitogenesis. Consistent expression was observed in the neural crest, which is known to have high morphogenetic potential.
Arachidonic acid reduces the stress response of gilthead seabream Sparus aurata L.
Authors: Van Anholt R. D. , Spanings F. A. T. , Koven W. M. , Nixon O. , Bonga S. E. Wendelaar 
Published: August 2004

SUMMARY
In this study the influence of the dietary level of the fatty acid arachidonic acid (ArA, 20:4n-6) was determined on the acute stress response and osmoregulation of adult gilthead seabream Sparus aurata L. Seabream were fed a diet containing either 0.9% or 2.4% of total fatty acids as ArA for 18 days before being subjected to a 5 min period of net confinement. Prior to this stressor, a subgroup of fish from both dietary treatment groups was treated with acetylsalicylic acid (ASA), an irreversible blocker of cyclooxygenase (COX). This would indicate whether any effects were caused by an enhanced synthesis of prostaglandins derived from ArA. The highest ArA levels were found in the kidneys, and these were further enhanced by dietary ArA-supplementation. In gill tissues, there were significant changes in all selected fatty acid classes 24 h after confinement, except for the docosahexaenoic acid (DHA, 22:6n-3): eicosapentaenoic acid (EPA, 20:5n-3)ratio. ArA feeding strongly reduced the cortisol response to confinement,which was partially counteracted by ASA treatment. ArA also attenuated the stress-associated increase in plasma osmolality and, in combination with ASA,enhanced the osmolality and plasma chloride levels, but reduced plasma sodium levels after confinement. Furthermore, ArA enhanced the branchial Na+, K+-ATPase activity both before and after confinement, whereas feeding ASA diminished this effect. It appeared that the effects of ArA-supplementation could not always be ascribed to an increase in prostaglandin synthesis. It is advisable to determine the long-term effects of replacing fish oils in commercial diets with vegetable oils that contain no long-chain fatty acids, particularly in carnivorous/marine species with low fatty acid elongation and desaturation activities. The effects of a low dietary intake of ArA (and other polyunsaturated fatty acids) should be studied over a longer term, taking into account any consequences for the health of the fish.
Bioconvective pattern formation ofTetrahymenaunder altered gravity
Authors: Mogami Yoshihiro , Yamane Akiko , Gino Atsuko , Baba Shoji A. 
Published: August 2004

SUMMARYBioconvection is a result of the negative gravitactic behavior of microorganisms. When the top-heavy density gradient generated by gravitaxis grows sufficiently large, an overturning convection occurs leading to a formation of characteristic patterns, which involve highly concentrated aggregation of cells into extended two-dimensional structures. Although gravity is a crucial factor, few experiments have been done with reference to gravity as an experimental variable. In order to gain an insight into the hydrodynamic as well as biological dependence of the convective motion on gravity, we investigated changes in bioconvective patterns of Tetrahymena under altered gravity acceleration generated by a long-arm centrifuge. Bioconvective patterns recorded of three different cell strains (T. pyriformis, T. thermophila and its behavioral mutant,TNR) were analyzed quantitatively using space-time plot and Fourier analysis. For example, under subcritical conditions, when T. pyriformis(1.0×106 cells ml-1) was placed in a 2 mm-deep chamber, no spatial pattern was observed at 1 g. When the suspension was centrifuged, however, patterns began to appear as acceleration increased over a critical value (1.5 g), and then remained steady. The formation was reversible, i.e. the patterns disappeared again as acceleration decreased. Under supracritical conditions, i.e. when a suspension of the same density was placed in a 4 mm-deep chamber, a steady state pattern was formed at 1 g. The pattern spacing in the steady state was observed to decrease stepwise in response to step increases in acceleration. Fourier analysis demonstrated that for TNR the mean wave number changed almost simultaneously with step changes in acceleration, whereas the responses were less sharp in the wild-type strains. This may suggest that the locomotor phenotype of the cell, such as its avoiding response ability, has a crucial role in bioconvective pattern formation. These findings are discussed in relation to former theoretical studies.
Renal function in Palestine sunbirds: elimination of excess water does not constrain energy intake
Authors: McWhorter Todd J. , del Rio Carlos Martínez , Pinshow Berry , Roxburgh Lizanne 
Published: August 2004

SUMMARY
Although the renal responses of birds to dehydration have received significant attention, the consequences of ingesting and processing large quantities of water have been less studied. Nectar-feeding birds must often deal with exceptionally high water intake rates in order to meet their high mass-specific energy demands. Birds that ingest large volumes of water may either eliminate excess water in the kidney or regulate the volume of water absorbed in the gastrointestinal tract. Because water absorption in the gastrointestinal tract of Palestine sunbirds (Nectarinia osea)decreases with increasing water ingestion rate, we predicted that glomerular filtration rate (GFR) in these birds would not be unusually high in spite of large ingested water loads. When feeding on dilute sucrose solutions, sunbirds ingested between 4 and 6 times their body mass in nectar per day, yet they were able to compensate for varying nectar energy density and increased thermoregulatory energy demands with no apparent difficulty. GFR was lower than predicted (1976.22±91.95 μl h-1), and was not exceptionally sensitive to water loading. Plasma glucose concentrations were high, and varied 1.8-fold between fasted (16.08± 0.75 mmol l-1) and fed (28.18±0.68 mmol l-1) sunbirds, but because GFR was low, glucose filtered load also remained relatively low. Essentially the entire glucose filtered load (98%) was recovered by the kidney. Renal fractional water reabsorption (FWR) decreased from 0.98 to 0.64 with increasing water intake. The ability of Palestine sunbirds to reduce the absorption of ingested water in the gastrointestinal tract may resolve the potential conflict between filtering a large excess of absorbed water in the kidney and simultaneously retaining filtered metabolites.
Electrodepositing Redox Polymer on Sandwich Complex for the Improvement of Sensitivity in Sandwich Enzyme-linked Immunoassay
Authors: Gao Qiang , Qi Bin , Sha Yufang , Yang Xiurong 
Published: August 2004

Abstract
Improvement of the sensitivity of electrochemical sandwich enzyme immunoassay has been achieved by electrodepositing redox polymer on screen-printed carbon electrode surface, on which the sandwich complex was formed.
Preparation of a Nanocrystalline TiO2 Photocatalyst Using a Dry-process with Acetylene Black
Authors: Tang Weiping , Chen Zaihua , Katoh Shunsaku 
Published: August 2004

Abstract
Well-dispersed anatase-type TiO2 nanocrystals showing good photocatalytic activity were prepared for the first time by a dry-process involving only the heating of a mixture of titanium tetraisopropoxide and acetylene black.
Artificial Assembly of Myoglobin and Flavodoxin Reductase Using Designed Coiled-coil Peptides
Authors: Sakamoto Seiji , Itoh Atsushi , Kudo Kazuaki 
Published: August 2004

Abstract
A unique and artificial assembly of myoglobin and flavodoxin reductase was constructed using a heterodimeric coiled-coil formation of de novo designed polypeptides in order to demonstrate a novel method for the artitecture of the active-site directed fusion protein.
Biomimetic Hydrolysis of p-Nitrophenyl Alkanoates with Functionalized Mesoporous Silicas
Authors: Chang Jeong Ho , Kim Kyung Ja , Shin Young-Kook , Liu Jun 
Published: August 2004

Abstract
A biomimetic catalysis of p-nitrophenyl alkanoate esters as a function of their alkyl chain lengths through multifunctionalization of molecular self-assembly onto ordered silica nanopores has been investigated in Tris-HCl buffer, and their kinetic parameters were calculated including a Michaelis–Menten kinetics.
4-Difluoromethylated Quinoline Synthesis via Intramolecular SN2′ Reaction of α-Trifluoromethylstyrenes Bearing Imine Moieties
Authors: Mori Takashi , Ichikawa Junji 
Published: August 2004

Abstract
Intramolecular cyclization of o-methyleneamino-substituted α-trifluoromethylstyrenes is promoted by DBU and a catalytic amount of KCN to provide 4-(difluoromethyl)quinolines. The reaction proceeds via (i) the generation of carbon nucleophiles from the imine moieties, (ii) their intramolecular SN2′ reaction with loss of a fluoride ion, and (iii) subsequent aromatization by alkene isomerization.
A Novel BEDT-TTF-based Organic Conducting Salt with a Ferrocene-containing Dianion, α-(BEDT-TTF)4(Fe(Cp–CONHCH2SO3)2)·4H2O
Authors: Furuta Keigo , Akutsu Hiroki , Yamada Jun-ichi , Nakatsuji Shin’ichi 
Published: August 2004

Abstract
We have prepared a new organic dianion containing the ferrocene derivative, Fe(C5H4–CONHCH2SO3−)2, as a PPh4 salt. Cyclic voltammetry indicates its oxidation potential is 0.14 V higher than that of BEDT-TTF. Electrocrystallization with BEDT-TTF gave the title compound. Its crystal structure and physical properties are reported.
Photophysical and Photocatalytic Properties of Molybdates and Tungstates with a Scheelite Structure
Authors: Kato Hideki , Matsudo Naoko , Kudo Akihiko 
Published: August 2004

Abstract
Photophysical and photocatalytic properties of molybdates and tungstates with a scheelite structure were investigated. The band gaps of scheelite compounds narrowed when the compounds were composed of Ag+ and Bi3+ ions. (NaBi)0.5MoO4 (BG: 3.1 eV) and (AgBi)0.5MoO4 (BG: 3.0 eV) showed the photocatalytic activities for O2 evolution from an aqueous solution containing an electron acceptor. On the other hand, (NaBi)0.5WO4 (BG: 3.5 eV) produced H2 from an aqueous solution containing an electron donor.
Hydrogen Adsorption/Desorption Property of Activated Carbon Loaded with Platinum
Authors: Takagi Hideyuki , Hatori Hiroaki , Yamada Yoshio 
Published: August 2004

Abstract
The hydrogen adsorption isotherms of activated carbon fiber loaded with platinum (Pt–ACF) in the 303–673 K range indicated that a temperature above 573 K was required to give rise to an increase in the amount of adsorbed hydrogen due to the spillover phenomenon. Two peaks at 800 and 1200 K in the D2 desorption profile of Pt–ACF clarified that two kinds of sites for adsorption or bonding of spiltover deuterium exist on the carbon surface.
Failure of a trial evaluating the effect of venous surgery on healing and recurrence rates in venous ulcers? The USABLE trial: rationale, design and methodology, and reasons for failure
Authors: Davies A H , Hawdon A J , Greenhalgh R M , Thompson S 
Published: August 2004

Objective: This Medical Research Council funded trial was set up to investigate whether venous surgery provided any additional benefit in the healing and recurrence rates of venous ulcers over compression bandaging alone. Methods: Ulcer surgery as adjuvant to compression bandaging for leg ulcers (USABLE) was a multicentre, randomized controlled trial, which planned to recruit 1000 venous ulcer patients to receive either compression bandaging alone or compression bandaging plus venous surgery. Follow up recorded ulcer healing, recurrence and patient quality of life. Results: Recruitment was slow, and involved screening a large number of patients (759) with only 75 randomized over an 18-month recruitment period. Conclusions: The results would infer that surgery is unlikely to be a management option for the majority of patients presenting to a hospital with a gaiter area leg ulcer.