bluuebunny/crossref_metadata_2025_split huggingface dataset:
Temperature sex determination in the European sea bass, Dicentrarchus labrax (L., 1758) (Teleostei, Perciformes, Moronidae): Critical sensitive ontogenetic phase
Authors: Koumoundouros George , Pavlidis Michalis , Anezaki Lina , Kokkari Constantina , Sterioti Aspasia , Divanach Pascal , Kentouri Maroudio 
Published: August 2002

AbstractThe temperature sex determination (TSD) mechanism in the European sea bass (Dicentrarchus labrax L.) was studied in respect to: a) the TSD sensitivity during the different developmental stages; and b) the intrapopulation correlation of sex determination with the growth rate up to the end of the TSD‐sensitive period. At the stage of half‐epiboly, eggs from the same batch were divided into four groups and subjected to different thermal treatments: a) 15°C (G15 group) and b) 20°C (G20 group) up to the middle of metamorphosis stage; c) 15°C up to the end of yolk‐sac larval stage and subsequently to 20°C (G15‐5 group); and d) 15°C up to the end of the preflexion stage and then to 20°C (G15‐10 group). At the end of the treatments, size grading was applied and four additional populations were established from the upper (L) and lower (S) size portions of the G15 and G20 populations: G15L, G15S, G20L, and G20S. During the following growing phase, all populations were subjected to common rearing conditions. The sex ratios of each population were macroscopically determined at 190–210 mm mean total length. Female incidence was significantly affected (P < 0.05) by the different thermal treatments: 66.1% in the G15, 47.1% in the G15‐10, 37.6% in the G15‐5, and 18.1% in the G20 group. In addition, sex ratio was correlated with the growth rate of the fish up to the end of the TSD‐sensitive period, with the larger fish presenting a significantly higher (P < 0.01) female incidence than the smaller fish in both thermal regimes tested: 73.1% in G15L vs. 57% in G15S, and 36.6% in G20L vs. 22.5% in G20S group. Results provide, for the first time, clear evidence that the sea bass is sensitive to TSD during all different ontogenetic stages up to metamorphosis, and that sex ratio is correlated with the growth rate of the fish well before the differentiation and maturation of the gonads. J. Exp. Zool. 292:573–579, 2002. © 2002 Wiley‐Liss, Inc.
Cell signaling and ion transport across the fish gill epithelium
Authors: Evans David H. 
Published: August 2002

AbstractA large array of circulating and local signaling agents modulate transport of ions across the gill epithelium of fishes by either affecting transport directly or by altering the size and distribution of transporting cells in the epithelium. In some cases, these transport effects are in addition to cardiovascular effects of the same agents, which may affect the perfusion pathways in the gill vasculature and, in turn, affect epithelial transport indirectly. Prolactin is generally considered to function in freshwater, because it is the only agent that allows survival of some hypophysectomized fish species in freshwater. It appears to function by either reducing branchial permeability, Na,K‐activated ATPase activity, or reducing the density of chloride cells. Cortisol was initially considered to produce virtually opposite effects (e.g., stimulation of Na,K‐activated ATPase and of chloride cell size and density), but more recent studies have found that this steroid stimulates ionic uptake in freshwater fishes, as well as the activity of H‐ATPase, an enzyme thought to be central to ionic uptake. Thus, cortisol may function in both high and low salinities. Growth hormone and insulin‐like growth factor appear to act synergistically to affect ion regulation in seawater fishes, stimulating both Na,K‐activated ATPase and Na‐K‐2Cl co‐transporter activity, and chloride cell size, independent of their effects on growth. Some of the effects of the GH–IGF axis may be via stimulation of the number of cortisol receptors. Thyroid hormones appear to affect seawater ion regulation indirectly, by stimulating the GH–IGF axis. Natriuretic peptides were initially thought to stimulate gill ionic extrusion, but recent studies have not corroborated this finding, so it appears that the major mode of action of these peptides may be reduction of salt loading by inhibition of oral ingestion and intestinal ionic uptake. Receptors for both arginine vasotocin and angiotensin have been described in the gill epithelium, but their respective roles and importance in fish ion regulation remains unknown. The gill epithelium may be affected by both circulating and local adrenergic agents, and a variety of studies have demonstrated that stimulation of α‐adrenergic versus β‐adrenergic receptors produces inhibition or stimulation of active salt extrusion, respectively. Local effectors, such as prostaglandins, nitric oxide, and endothelin, may affect active salt extrusion as well as gill perfusion. Recent studies have suggested that the endothelin inhibition of salt extrusion is actually mediated by the release of both NO and prostaglandins. It is hoped that modern molecular techniques, combined with physiological measurements, will allow the dissection of the relative roles in ion transport across the fish gill epithelium of this surprisingly large array of putative signaling agents. © 2002 Wiley‐Liss, Inc.
Alterations in habituation of the tail flip response in epigean and troglobitic crayfish
Authors: Kellie Scott , Greer Jarrett , Cooper Robin L. 
Published: August 2002

AbstractWe demonstrate that the probability of the crayfish, P. clarkii, to tail flip in response to a touch on the dorsal tail fan is dependent on both the size and the behavioral state of the animal. Alterations in the animal’s internal physical state, such as when the animal autotomizes its chelipeds, will cause larger‐sized animals to tail flip; if they were not autotomized, then no tail flip response would occur. Altering the external environment by removal of water causes small crayfish, which normally habituate slowly, to rapidly habituate. Observation of large adult crayfish in a species, O. australis packardi, one that evolved to live in total cave darkness, revealed that they are more likely to tail flip than are the sighted, adult P. clarkii. Results indicate that the behavioral state of the crayfish can result in rapid and long‐term alterations in the tail flip response and in habituation rates to repetitive stimuli. This ability to show plasticity in gain setting may be regulated by neuromodulators and can occur in large adults of the sighted crayfish. Differences between the two species indicate that size may not be the sole contributing factor to account for tail flip behaviors. J. Exp. Zool. 290:163–176, 2001. © 2001 Wiley‐Liss, Inc.
Bafilomycin A1 inhibits proteolytic cleavage and hydration but not yolk crystal disassembly or meiosis during maturation of sea bass oocytes
Authors: Selman Kelly , Wallace Robin A. , Cerdà Joan 
Published: August 2002

AbstractOocytes of the black sea bass, Centropristes striata, were enlarged in volume more than three‐fold over a 24‐hr period during oocyte maturation, both in vivo and in vitro. At the same time, the opaque oocytes clarified while the crystalline yolk inclusions lost their ordered structure, fused with one another, and formed a continuous electron‐lucent mass. The oocyte size increase was due almost entirely to water uptake, which was accompanied by the accumulation of Na+, K+, and free amino acids (FAAs). The absolute amounts of each of these small molecular weight osmotic effectors increased 2×, 4×, and over 10×, respectively, indicating that the generation of FAAs is the major cause of water uptake during maturation. Amino acid analyses indicated that the amounts of all amino acids except taurine increased, so that selective amino acids were not produced during maturation. The increase in FAAs was accompanied by the loss of certain high‐molecular‐weight yolk proteins and the generation of many smaller peptides. Oocytes stimulated to undergo maturation in the presence of bafilomycin A1, a specific inhibitor of the vacuolar ATPase‐dependent proton pump, clarified and underwent maturation but did not increase significantly in size. Cytological examination revealed that yolk crystals fused and became homogeneous but maintained their electron density. No evidence of proteolysis was found in bafilomycin A1‐treated oocytes and the generation of FAAs together with hydration was inhibited in a dose‐dependent manner (I50 = 3 nM bafilomycin A1). Taken together, we postulate that the pronounced oocyte hydration in marine teleosts that spawn pelagic (floating) eggs is accomplished by a two‐step process whereby (i) K+ influx promotes yolk crystal disassembly and yolk sphere fusion and (ii) acidification of the yolk spheres activates yolk proteolysis and concomitant hydration. Bafilomycin A1 inhibits only the second step so that many of the events of oocyte maturation, including germinal vesicle breakdown, occur in its presence but oocyte hydration is suppressed. J. Exp. Zool. 290:265–278, 2001. © 2001 Wiley‐Liss, Inc.
Synthesis of 14C‐labelled sulforaphane
Authors: Kuhnert Nikolai , Holst Birgit , Williamson Gary 
Published: August 2002

AbstractSulforaphane (SFN) a naturally occurring isothiocyanate present in broccoli, shows strong evidence of anti‐carcinogenic activity. The mechanism of action, absorption, distribution, metabolism and excretion of the compound is however still poorly understood and requires a radiolabelled version of the compound for further studies. The paper describes an optimised cold synthesis of SFN and a radiosynthesis of 14C‐labelled SFN. Copyright © 2001 John Wiley & Sons, Ltd.
Synthesis of 10,11,14,15‐13C4‐and 14,15‐13C2‐retinyl acetate
Authors: Tanumihardjo Sherry A. 
Published: August 2002

AbstractThe synthesis of 10,11,14,15‐13C4‐ and 14,15‐13C2‐retinyl acetate is described. The procedure uses a modified Wittig‐Horner synthesis. By using the 13C isotope, sensitive gas chromatography‐combustion‐isotope ratio mass spectrometry can be used for analysis in application to human isotope dilution studies. Copyright © 2001 John Wiley & Sons, Ltd.
Synthesis of asymmetric [75Se]selenoethers via carbodiimides
Authors: Blum T. , Ermert J. , Coenen H. H. 
Published: August 2002

AbstractA convenient radiosynthesis of asymmetric [75Se]selenoethers was developed using 1,3‐disubstituted [75Se]selenoureas as intermediates. These were prepared from appropriate carbodiimides and hydrogen [75Se]selenide, which could only be generated from carrier‐added (c.a.) [75Se]selenite in aqueous solution using phosphinic acid as reducing agent. Optimization of this initial labelling step with dicyclohexylcarbodiimide and polymeric N‐cyclohexylcarbodiimide‐N′‐methyl polystyrene resulted in radiochemical yields (RCY) of 73 and 55% (bound on the polymer), respectively, within 45 min. Treatment of [75Se]selenoureas with alkylbromides led to corresponding [75Se]selenouronium salts in nearly quantitative yields. Hydrolysis under basic conditions provided the [75Se]selenolates and a second alkylation yielded asymmetric [75Se]selenoethers. Thus, within 90 min benzylmethyl[75Se]selenide, benzylbutyl[75Se]selenide, benzylisopropyl[75Se]selenide and 1‐phenyl‐l‐(methyl[75Se]seleno)ethane were synthesized with respective RCY of about 59, 55, 10 and 60%. Furthermore, the 75Se‐labelled alkylating agent 3‐(methyl[75Se]seleno)‐1‐propanyl p‐toluenesulfonate and [75Se]selenomethionine were obtained with radiochemical yields of 51 and 41%, respectively. Copyright © 2001 John Wiley & Sons, Ltd.
Testis differentiation in the glowworm, Lampyris noctiluca, with special reference to the apical tissue
Authors: Balles S. , Maas U. , Sehn E. , Dorn A. 
Published: August 2002

AbstractThe gonads of Lampyris noctiluca are sexually undifferentiated during the first larval instars. They consist of many gonadal follicles that include the germ stem cells enclosed by the somatic cells of the follicle wall. Follicle wall cells are more numerous at the follicle apices than at the distal parts, but different cell types cannot be distinguished. In male larvae, the appearance of apical follicle tissue, derived from follicle wall cells, marks the onset of testis differentiation. When maximally expressed, the apical tissue occupies about the upper half of the testis follicles and can be observed in larvae of the fifth and sixth instar. The apical tissue is characterized by its “light” appearance (due to poor stainability) caused by the small number cellular organelles, especially a paucity of free ribosomes. Maximal expression of the apical tissue must be very brief, since in most examined fifth and sixth instar larvae the apical tissue is partly or mostly translocated into the center of the upper half of the follicles and spermatogonia then occupy the apical follicle tips. During and after translocation apical cells form projections that grow around clusters of spermatogonia (spermatocysts). Thus, the apical cells transform into spermatocyst envelope cells. They retain their “light” appearance but undergo dramatic subcellular differentiation: smooth ER becomes extremely prominent, forming stacks and whorls of parallel cisternae. Golgi complexes are also conspicuous. The cellular organization suggests secretory activity. The possibility of ecdysteroid production and its function is discussed. The spermatocyst envelope cells persist into the pupal stage. When spermiohistogenesis takes place in cysts, cyst envelope cells show signs of regression. At all stages of testis development apical cells and their derivatives, the spermatocyst envelope cells, phagocytize degenerating spermatogonia. Although this is an important task of these cells, the impressive formation of sER in the cyst envelope cells is indicative of an additional, as yet unknown, function. J. Morphol. 251:22–37, 2002. © 2002 Wiley‐Liss, Inc.
Relaxation effects of clustered particles
Authors: Tanimoto Akihiro , Oshio Koichi , Suematsu Makoto , Pouliquen Daniel , Stark David D. 
Published: August 2002

AbstractRelations between spatial distribution of superparamagnetic iron oxide (SPIO) particles and the image contrast caused by SPIO were investigated. Actual clustering pattern of particles was measured in the liver and spleen of animals using intravital laser confocal microscopy. SPIO‐doped phantoms with and without Sephadex beads were made to simulate these patterns, and relaxation parameters were measured using a 1.5‐T clinical scanner. Finally, these results were compared to clinical image data using SPIO particulate agent. Intravital microscopy indicated that the clustering of latex beads was more predominant in hepatic Kupffer cells than in splenic macrophages (P < 0.001). Phantoms without Sephadex beads showed an approximately linear increase of 1/T1 (R1), 1/T2 (R2) and 1/T2* (R2*) values with increasing SPIO concentration. However, with Sephadex beads, R1 and R2 showed little change with increasing SPIO concentration, while R2* showed the same linear increase with SPIO. Also, the R2* values were higher with Sephadex beads. These results were consistent with the clinical imaging data, where signal reduction was significantly smaller in the spleen (‐0.4% ± 27.4%) than in the liver (50.4% ± 16.8%, P < 0.00001) on T2*‐weighted images, but the reduction in the spleen (47.2% ± 16.1%) was equivalent to the liver (38.8% ± 26.0%) on T2‐weighted images. J. Magn. Reson. Imaging 2001;14:72–77. © 2001 Wiley‐Liss, Inc.
Sequencing of new beauverolides by high‐performance liquid chromatography and mass spectrometry
Authors: Kuzma Marek , Jegorov Alexandr , Kačer Petr , Havlíček Vladimír 
Published: August 2002

AbstractMass spectrometry (MS) and tandem mass spectrometry (MSn) were used for the identification of beauverolides in the fermentation broth of Beauveria bassiana and for evaluation of the purified fraction obtained by sublimation of beauverolides. Besides being a new efficient route for purification of beauverolides, sublimation provided an enrichment of new minor lipophilic beauverolides of lower molecular weight from the original complex mycelial extract. The product ion collision‐induced dissociation (CID) spectra obtained on an ion trap (electrospray ionization), the in‐source CID mass spectra on a sector instrument (atmospheric‐pressure chemical ionization) and the post‐source decay matrix‐assisted laser desorption/ionization mass spectra of beauverolides were compared and evaluated. All MSn experiments started with singly charged precursor ions. The following two new representatives of this group of compounds were identified by high‐performance liquid chromatography and MS (HPLC/MS): cyclo‐(3‐hydroxy‐4‐methyloctanoylvalylalanylleucyl) and cyclo‐(3‐hydroxy‐4‐methyloctanoyltyrosylalanylleucyl). Individual structures were confirmed by preparative isolation and nuclear magnetic resonance spectroscopy. The structure of a third novel and minor beauverolide was tentatively assigned by HPLC/MS only as cyclo‐(3‐hydroxy‐4‐methyldecanoylvalylalanylLxx), Lxx = leucyl, isoleucyl, or allo‐isoleucyl. Copyright © 2001 John Wiley & Sons, Ltd.
Characterization of a phosphorylated peptide and peptoid and peptoid–peptide hybrids by mass spectrometry
Authors: Ruijtenbeek Rob , Versluis Cees , Heck Albert J. R. , Redegeld Frank A. M. , Nijkamp Frans P. , Liskamp Rob M. J. 
Published: August 2002

AbstractNano‐electrospray tandem mass spectrometry (nano‐ES‐MS/MS) was used to record collision‐induced dissociation (CID) spectra of a set of peptoid–peptide hybrids and the complete peptoid derived from the phosphopeptide Ac‐pTyr‐Glu‐Thr‐Leu‐NH2 (1). The presence of B and Y″‐type fragment ions in the tandem mass spectra of the protonated molecular ions [M + H]+ allowed confirmation of sequence similar to mass spectrometric sequence analysis in peptides. In the isomeric peptoid compounds studied, one or several amino acid residues were replaced by peptoid residues (N‐substituted glycine residues), which resulted in characteristic tandem mass spectra with differently increased relative abundances of Y″‐and B‐type fragment ions. The increment of a particular Y″‐ion was directly correlated to the position of a peptoid residue present. In addition to these increased peak intensities, other characteristic peaks were also observed compared with the spectrum of reference peptide 1. When a peptoid phosphotyrosine was incorporated, the presence of this residue was apparent from the occurrence of a relatively intense peak at m/z 187 representing the positively charged side‐chain of phosphotyrosine, which was almost absent in the spectrum of the reference peptide 1. Since the threonine side‐chain had to be translated into the homo peptoid analog this substitution was apparent from the presence of [M + H]+ and fragment ions 14 mass units higher than observed in the spectrum of the reference phosphopeptide 1. The presence of an NLeu peptoid residue could be confirmed by the specific fragmentation of the immonium ion showing an intense peak in its tandem mass spectrum at m/z 57, which results from the loss of an neutral imine molecule leading to a positively charged [C4H9]+ ion. By means of these mass spectrometric characteristics, all isomeric peptoid compounds could be distinguished from each other and characterized. The methods used appear to be very useful in future studies of peptoids and peptoid–peptide hybrids. Copyright © 2001 John Wiley & Sons, Ltd.
Characteristics of puumala and Dobrava infections in Croatia*
Authors: Markotić A. , Nichol S.T. , Kuzman I. , Sanchez A.J. , Ksiazek T.G. , Gagro A. , Rabatić S. , Zgorelec R. , Avšič‐Županc T. , Beus I. , Dekaris D. 
Published: August 2002

AbstractIn this study, two different hantaviruses, Puumala virus (PUUV) and Dobrava virus (DOBV), were demonstrated for the first time to coexist and cause hemorrhagic fever with renal syndrome (HFRS) in Croatia. Phylogenetic analysis showed some differences among the nucleotide sequences of PUUV originating from Dinara mountain, which was more closely related to Austrian PUUV than other Croatian PUUV from Mala Kapela mountain. More consistency was found among the Croatian DOBV. HFRS was verified in 85 of 201 suspected cases recorded in 1995 during the largest HFRS outbreak in Croatia. Most of these cases were soldiers. With the exception of the coastal region and islands, all of Croatia was found to be an area endemic for HFRS. A statistically significantly higher proportion of DOBV‐infected patients had acute renal failure, visual disturbance, severe thrombocytopenia, and elevated levels of nonsegmented leukocytes, creatine, and total bilirubin. The prevalence of gastrointestinal and electrocardiography disorders also was greater in DOBV‐infected patients. Interestingly, significantly more PUUV‐infected patients had elevated systolic blood pressure on admission to the hospital. Further prospective studies are necessary to shed more light on differences in HFRS severity associated with PUU and DOB viruses. J. Med. Virol. 66:542–551, 2002. © 2002 Wiley‐Liss, Inc.
Cytokine gene expression and protein production in peripheral blood mononuclear cells of children with acute dengue virus infections
Authors: Gagnon Susan J. , Mori Masuko , Kurane Ichiro , Green Sharone , Vaughn David W. , Kalayanarooj Siripen , Suntayakorn Saroj , Ennis Francis A. , Rothman Alan L. 
Published: August 2002

AbstractPlasma leakage in dengue hemorrhagic fever (DHF) is associated with elevated plasma levels of cytokines. To define further the contribution of immune activation to DHF and the source of cytokines, we analyzed the production of cytokines in peripheral blood mononuclear cells (PBMC) obtained from children with dengue, using RT‐PCR and immunostaining. Tumor necrosis factor‐α (TNF‐α) and TNF‐β expression was detected in all samples by PCR and in < 50% of samples by immunostaining. Interferon‐γ (IFN‐γ) expression was detected in < 50% of samples by either method. Interleukin‐2 (IL‐2) and IL‐4 expression was detected in a few samples by immunostaining but was not detectable by PCR. We found greater expression of TNF‐α and IL‐4 in DHF than in dengue fever or other (non‐dengue) febrile illnesses. These results support the model of immunopathogenesis of DHF. However, low levels of cytokine expression in PBMC suggest that cellular activation in tissues may contribute to high serum cytokine levels in DHF. J. Med. Virol. 67:41–46, 2002. © 2002 Wiley‐Liss, Inc.