bluuebunny/crossref_metadata_2025 huggingface dataset:
Histone deacetylase 3 (HDAC3) activity is regulated by interaction with protein serine/threonine phosphatase 4
Authors: Zhang Xiaohong , Ozawa Yukiyasu , Lee Heehyoung , Wen Yu-Der , Tan Tse-Hua , Wadzinski Brian E. , Seto Edward
Published: April 2005

Histone deacetylase 3 (HDAC3) is one of four members of the human class I HDACs that regulates gene expression by deacetylation of histones and nonhistone proteins. Early studies have suggested that HDAC3 activity is regulated by association with the corepressors N-CoR and SMRT. Here we demonstrate that, in addition to protein–protein interactions with NCoR/SMRT, the activity of HDAC3 is regulated by both phosphorylation and dephosphorylation. A protein kinase CK2 phosphoacceptor site in the HDAC3 protein was identified at position Ser424, which is a nonconserved residue among the class I HDACs. Mutation of this residue was found to reduce deacetylase activity. Interestingly, unlike other class I HDACs, HDAC3 uniquely copurifies with the catalytic and regulatory subunits of the protein serine/threonine phosphatase 4 complex (PP4c/PP4R1). Furthermore, HDAC3 complexes displayed protein phosphatase activity and a series of subsequent mutational analyses revealed that the N terminus of HDAC3 (residues 1–122) was both necessary and sufficient for HDAC3–PP4cinteractions. Significantly, both overexpression and siRNA knock-down approaches, and analysis of cells devoid of PP4c, unequivocally show that HDAC3 activity is inversely proportional to the cellular abundance of PP4c. These findings therefore further highlight the importance of protein–protein interactions and extend the significance of dephosphorylation in the regulation of HDAC activity, as well as present a novel alternative pathway by which HDAC3 activity is regulated.
Ubiquitin ligase MKRN1 modulates telomere length homeostasis through a proteolysis of hTERT
Authors: Kim Jun Hyun , Park Sun-Mi , Kang Mi Ran , Oh Sue-Young , Lee Tae H. , Muller Mark T. , Chung In Kwon
Published: April 2005

Telomere homeostasis is regulated by telomerase and a collection of associated proteins. Telomerase is, in turn, regulated by post-translational modifications of the rate-limiting catalytic subunit hTERT. Here we show that disruption of Hsp90 by geldanamycin promotes efficient ubiquitination and proteasome-mediated degradation of hTERT. Furthermore, we have used the yeast two-hybrid method to identify a novel RING finger gene (MKRN1) encoding an E3 ligase that mediates ubiquitination of hTERT. Overexpression ofMKRN1in telomerase-positive cells promotes the degradation of hTERT and decreases telomerase activity and subsequently telomere length. Our data suggest thatMKRN1plays an important role in modulating telomere length homeostasis through a dynamic balance involving hTERT protein stability.
Ancient haplotypes resulting from extensive molecular rearrangements in the wheat A genome have been maintained in species of three different ploidy levels
Authors: Isidore Edwige , Scherrer Beatrice , Chalhoub Boulos , Feuillet Catherine , Keller Beat
Published: April 2005

Plant genomes, in particular grass genomes, evolve very rapidly. The closely related A genomes of diploid, tetraploid, and hexaploid wheat are derived from a common ancestor that lived <3 million years ago and represent a good model to study molecular mechanisms involved in such rapid evolution. We have sequenced and compared physical contigs at the Lr10 locus on chromosome 1AS from diploid (211 kb), tetraploid (187 kb), and hexaploid wheat (154 kb). A maximum of 33% of the sequences were conserved between two species. The sequences from diploid and tetraploid wheat shared all of the genes, including Lr10 and RGA2 and define a first haplotype (H1). The 130-kb intergenic region between Lr10 and RGA2 was conserved in size despite its activity as a hot spot for transposon insertion, which resulted in >70% of sequence divergence. The hexaploid wheat sequence lacks both Lr10 and RGA2 genes and defines a second haplotype, H2, which originated from ancient and extensive rearrangements. These rearrangements included insertions of retroelements and transposons deletions, as well as unequal recombination within elements. Gene disruption in haplotype H2 was caused by a deletion and subsequent large inversion. Gene conservation between H1 haplotypes, as well as conservation of rearrangements at the origin of the H2 haplotype at three different ploidy levels indicate that the two haplotypes are ancient and had a stable gene content during evolution, whereas the intergenic regions evolved rapidly. Polyploidization during wheat evolution had no detectable consequences on the structure and evolution of the two haplotypes.
Forcing interactions as a genetic screen to identify proteins that exert a defined activity
Authors: DeVit Michael , Cullen Paul J. , Branson Margaret , Sprague George F. , Fields Stanley
Published: April 2005

The interaction of proteins to form macromolecular complexes is the basis for most biological processes. Approaches have been described that employ artificial constructs to promote such complexes and assess the consequences. For example, a protein interaction scheme has been described that examines the effects of a specific phosphorylation event catalyzed by a protein kinase via the provision of an artificial protein binding interface between a modified version of the kinase and a single substrate. We have generalized this type of approach to form the basis for a genetic selection to identify proteins that exert an activity when recruited to a target protein. The assay uses the leucine zipper domains from the mammalian transcription factors Fos and Jun to force the interaction of two proteins. With a target protein fused to the Jun zipper and a library of open reading frames fused to the Fos zipper, we demonstrate this approach in yeast with both a selection to identify membrane-associated proteins and a selection to identify candidate components of the filamentous growth MAP kinase pathway.
Extinction and renewal of Pavlovian modulation in human sequential Feature Positive discrimination learning
Authors: Baeyens Frank , Vansteenwegen Debora , Beckers Tom , Hermans Dirk , Kerkhof Ineke , De Ceulaer Annick
Published: April 2005

Using a conditioned suppression task, we investigated extinction and
renewal of Pavlovian modulation in human sequential Feature Positive (FP)
discrimination learning. In Experiment 1, in context a participants
were first trained on two FP discriminations, X→A+/A- and Y→B+/B-.
Extinction treatment was administered in the acquisition context a
(aaa group) or in a new context b (aba group), and
comprised X→A- extinction and Y- control trials. Discriminative
X→A/A responding was lost in both groups when tested in the extinction
context, but partially recovered in the aba and not in the
aaa group when tested in the acquisition context, suggesting
extinction and renewal of extinguished modulation. The same was observed for
the Y→B/B control pair, however, questioning whether the loss of
discriminative X→A/A responding represented genuine extinction of
modulation. In Experiment 2, including only aba groups, participants
were trained in context a on two FP discriminations, X→A+/A- and
Y→B+/B-, after which the group “Extinction” was exposed to
X→A- extinction trials in context b, whereas the group
“Control” was exposed to X- control trials; concurrently, both
groups received further Y→B+/B- training. In the group Control,
differential Y→B/B and X→A/A responding were acquired and maintained
throughout the experiment. In the group Extinction, while Y→B/B
responding was also maintained throughout, differential X→A/A responding
disappeared because of X→A- extinction treatment when tested in the
extinction context b, but partially reappeared when tested in the
acquisition context a. This evidences aba-renewal of
extinguished modulation.
The crystal structure of a partial mouse Notch‐1 ankyrin domain: Repeats 4 through 7 preserve an ankyrin fold
Authors: Lubman Olga Y. , Kopan Raphael , Waksman Gabriel , Korolev Sergey
Published: April 2005

Folding and stability of proteins containing ankyrin repeats (ARs) is of great interest because they mediate numerous protein–protein interactions involved in a wide range of regulatory cellular processes. Notch, an ankyrin domain containing protein, signals by converting a transcriptional repression complex into an activation complex. The Notch ANK domain is essential for Notch function and contains seven ARs. Here, we present the 2.2 Å crystal structure of ARs 4–7 from mouse Notch 1 (m1ANK). These C‐terminal repeats were resistant to degradation during crystallization, and their secondary and tertiary structures are maintained in the absence of repeats 1–3. The crystallized fragment adopts a typical ankyrin fold including the poorly conserved seventh AR, as seen in the Drosophila Notch ANK domain (dANK). The structural preservation and stability of the C‐terminal repeats shed a new light onto the mechanism of hetero‐oligomeric assembly during Notch‐mediated transcriptional activation.
One‐ and two‐body decomposable Poisson‐Boltzmann methods for protein design calculations
Authors: Marshall Shannon A. , Vizcarra Christina L. , Mayo Stephen L.
Published: April 2005

Successfully modeling electrostatic interactions is one of the key factors required for the computational design of proteins with desired physical, chemical, and biological properties. In this paper, we present formulations of the finite difference Poisson‐Boltzmann (FDPB) model that are pairwise decomposable by side chain. These methods use reduced representations of the protein structure based on the backbone and one or two side chains in order to approximate the dielectric environment in and around the protein. For the desolvation of polar side chains, the two‐body model has a 0.64 kcal/mol RMSD compared to FDPB calculations performed using the full representation of the protein structure. Screened Coulombic interaction energies between side chains are approximated with an RMSD of 0.13 kcal/mol. The methods presented here are compatible with the computational demands of protein design calculations and produce energies that are very similar to the results of traditional FDPB calculations.
Visualization of conformational distribution of short to medium size segments in globular proteins and identification of local structural motifs
Authors: Ikeda Kazuyoshi , Tomii Kentaro , Yokomizo Tsuyoshi , Mitomo Daisuke , Maruyama Keiichiro , Suzuki Shinya , Higo Junichi
Published: April 2005

Analysis of the conformational distribution of polypeptide segments in a conformational space is the first step for understanding a principle of structural diversity of proteins. Here, we present a statistical analysis of protein local structures based on interatomic Cα distances. Using principal component analysis (PCA) on the intrasegment Cα–Cα atomic distances, the conformational space of protein segments, which we call the protein segment universe, has been visualized, and three essential coordinate axes, suitable for describing the universe, have been identified. Three essential axes specified radius of gyration, structural symmetry, and separation of hairpin structures from other structures. Among the segments of arbitrary length, 6–22 residues long, the conservation of those axes was uncovered. Further application of PCA to the two largest clusters in the universe revealed local structural motifs. Although some of motifs have already been reported, we identified a possibly novel strand motif. We also showed that a capping box, which is one of the helix capping motifs, was separated into independent subclusters based on the Cα geometry. Implications of the strand motif, which may play a role for protein–protein interaction, are discussed. The currently proposed method is useful for not only mapping the immense universe of protein structures but also identification of structural motifs.
Crystal structure of yeast YHR049W/FSH1, a member of the serine hydrolase family
Authors: Quevillon‐Cheruel Sophie , Leulliot Nicolas , Graille Marc , Hervouet Nadège , Coste Frank , Bénédetti Hélène , Zelwer Charles , Janin Joel , Van Tilbeurgh Herman
Published: April 2005

Yhr049w/FSH1 was recently identified in a combined computational and experimental proteomics analysis for the detection of active serine hydrolases in yeast. This analysis suggested that FSH1 might be a serine‐type hydrolase belonging to the broad functional αβ‐hydrolase superfamily. In order to get insight into the molecular function of this gene, it was targeted in our yeast structural genomics project. The crystal structure of the protein confirms that it contains a Ser/His/Asp catalytic triad that is part of a minimal α/β‐hydrolase fold. The architecture of the putative active site and analogies with other protein structures suggest that FSH1 may be an esterase. This finding was further strengthened by the unexpected presence of a compound covalently bound to the catalytic serine in the active site. Apparently, the enzyme was trapped with a reactive compound during the purification process.
Diel and seasonal distribution of perch in Lake Constance: a hydroacoustic study and in situ observations
Authors: Imbrock F. , Appenzeller A. , Eckmann R.
Published: April 2005

A near‐shore belt 50 km in length was surveyed parallel to the shoreline of Lake Constance, central Europe, with a single‐beam echosounder five times between July 1993 and February 1994. The species and age composition of fish in the survey area was investigated by gillnet fishing and SCUBA‐diving. In summer, the horizontal distribution of perch was patchy. Population density declined from east to west, and highest densities occurred in one shallow bay and close to ports and jetties at steeper shores. During daytime, perch stayed in the sublittoral zone between 3 and 15 m depth and between 2 and 6 m above the thermocline. Within this layer age classes were separated spatially: the relative number of young‐of‐the‐year perch declined with depth whereas the relative number of adult perch (2+ and older) increased with depth. At dusk the fish migrated to the littoral zone, where they spent the night resting on the bottom. In winter, under almost homothermal conditions, perch of all ages were located between the 35 and 70 m depth contours, where they performed pronounced diel vertical migrations. They rested on, or close to, the bottom during daytime and ascended up to 20 m below the surface at night. During this season, horizontal distribution of perch was much more homogeneous than in summer.
Growth, diet and condition of corkwing wrasse and rock cook on the west coast of Scotland
Authors: Sayer M. D. J. , Gibson R. N. , Atkinson R. J. A.
Published: April 2005

A study of seasonal and sexual variations of growth, diet, somatic condition (KS), gonadosomatic condition (GSI) and hepatosomatic condition (HSI) of corkwing wrasse Crenilabrus melops (L.), and rock cook Centrolabrus exoletus was made on specimens taken from areas on the west coast of Scotland from May 1992 to February 1994. Capture throughout the year was by baited creel, 3‐m beam trawl, fyke net or by anaesthetics applied underwater. Corkwing ranged in size from 31–212 mm and 0.3–131.2 g for males, and 31–203 mm and 0.3–103–5 g for females. Maximum corkwing ages were 6+ years for males, 7+ years for females. Male rock cook ranged in size from 43–165 mm, weighed 0.7–56–5 g, and had a maximum age of 8+ years; females ranged in size from 43–138 mm, weighed 0.7–39.3 g, and had a maximum age of 4+ years. Male growth rates were faster for both species. Male and female corkwing had low KS values during the period of high GSI values; the trends for rock cook KS values were more variable, but levels increased after the reproductive period. Maximum GSI values were 11.37 and 18.94 for male and female corkwing respectively, 9.63 and 16.63 for male and female rock cook. There was no seasonal HSI fluctuation for male corkwing, levels were higher during the reproductive period for female corkwing and male rock cook, lower during the same period for female rock cook. The diets of corkwing and rock cook were both dependent on epibenthos. Corkwing diet was dominated by gastropod molluscs. The management of sustainable fisheries for corkwing and rock cook is discussed in relation to the growth rates of the two species.
Correlation between environmental parameters and behaviour during high tides in Periophthalmus modestus
Authors: Ikebe Y. , Oishi T.
Published: April 2005

Migratory behaviour in relation to tides was investigated in the mudskipper Periophthalmus modestus at a small estuary in southern Japan. Fish remained and fed on the tideland at low tides, but migrated along the water edge and clung to the wall of the bank above high tidemark at high tides. The number of the mudskippers clung to the wall of the bank at high tides increased from spring to summer with an increase in air temperature, but then decreased as air temperature became lower. The seasonal fluctuation of the number of clinging fish was positively correlated to that of air temperature, and negatively correlated to that of dissolved oxygen. Since metabolic rate increases with the increase of environmental temperature, the migratory and clinging behaviours may reflect behavioural adaptation to terrestrial life in terms of oxygen respiration.
Eosinophilic granulocytes in the epidermis of Oreochromis mossambicus gill filaments studied in situ
Authors: Barnett R. R. , Akindele T. , Orte C. , Shephard K. L.
Published: April 2005

Granular cells were observed in the epidermis of isolated gill filaments using Normaski microscopy at×400 magnification. Granulocytes were motile and chemotactic to histamine (introduced via a micropipette into the filament) and to the products of degranulation of neighbouring granulocytes within the epidermis. The abundance of visible granulocytes within the epidermis of gill filaments was increased in the period following net capture, confirming their migratory ability. Cells isolated from gill tissue are poorly glass adherent. They are also eosinophilic and more dense than macrophages and lymphocytes on a discontinuous percoll gradient. They are identified as eosinophils on the basis of these characteristics.
Microsatellite DNA markers for genetic mapping in Oreochromis niloticus
Authors: Lee W.‐J. , Kocher T. D.
Published: April 2005

The isolation of seven tri‐, and 133 di‐nucleotide microsatellite markers from a tilapia, Oreochromis niloticus, is described. An efficient methodology for isolating large numbers of such markers and their potential applications in applied aquaculture and evolutionary genetics are discussed.
Size‐assortativeness in multi‐species fish shoals
Authors: Krause J. , Godin J.‐G. J. , Brown D.
Published: April 2005

Theory predicts that fish should assort in shoals on the basis of similar phenotypic traits to minimize predation risk and to maximize foraging efficiency. A single phenotypic character, body size, was considered and the hypothesis tested that free‐ranging fish shoals are sizeassorted. Furthermore, a second test investigated whether fish within multi‐species shoals are more strongly size‐assorted with conspecifics than with heterospecifics. Twelve fish shoals, each comprising two different species (golden shinerNotemigonus crysoleucas, and banded killifishFundulus diaphanus) were caught in the littoral zone of a north temperate lake using a beach seine. Shoal membership size ranged from 36 to 776 fish, and mean standard body length of members ranged from 18 to 34 mm. Fish were assorted by body size at two different levels, namely, between shoals and at the level of species within shoals. Body sizes of shiners and killifish within shoals were significantly different in seven out of 12 shoals, with killifish being the larger species in five cases and shiners being the larger one in two cases. Because there is considerable overlap in body size between the two species in the population, the observed species‐related size‐assortativeness within shoals was not just the by‐product of a directional size difference (between species) in the population. These findings provide strong quantitative evidence for size‐sorting in free‐ranging fish shoals and raise questions concerning the formation of multi‐species fish shoals.
Sperm release behaviour and fertilization in the grass goby
Authors: Ota D. , Marchesan M. , Ferrero E. A.
Published: April 2005

Nesting males of the grass goby Zosterisessor ophiocephalus showed bouts, with intervals of c. 30 min duration, of upside‐down movements while rubbing its genital papilla onto the ceiling of its burrow. Such behaviour was shown during female courting and spawning, and even after female removal. Observations showed that this behaviour was associated with the release of a sperm trail on the substratum and clumped spermatozoa in water, agglutinated with a mercury‐bromophenol blue and PAS positive glycoprotein secretion of the sperm duct glands. Agglutination in the secretion delayed the activation of spermatozoa and contributed a steady supply, for up to 40 min, of motile spermatozoa during prolonged egg laying by the female. Sperm released before egg laying achieved c. 50% fertilization success compared with nearly 100% obtained if the sperm was released during egg laying. The sperm release behaviour may improve the nest owner's reproductive success against intruders or sneakers. It also allows defence of the nest while the female is spawning and may allow the male to court other females in the proximity.
Gut evacuation and absorption efficiency of walleye larvae
Authors: Johnston T. A. , Mathias J. A.
Published: April 2005

Gut evacuation and absorption efficiency in zooplanktivorous walleye Stizostedion vitreum larvae (10–19 mm; 0.53–6.8 mg dry weight) were examined in the laboratory. The decline in dry weight of whole digestive tract contents was examined at 15, 20, and 25) C in discontinuous feeding larvae. The observed relationship between short‐term evacuation rate and gut fullness indicated that evacuation approximated most closely an exponential decline. When gut evacuation rate, R, was calculated as the slope of loge gut fullness v. time there were significant effects of temperature and walleye size on R. Gut evacuation rate was higher at 20° C than at 15 or 25° C and declined with increasing walleye dry weight. Absorption efficiency at 20° C was examined by qualitative analysis of food and faeces. Apparent digestibility, Da, of crustacean zooplankton increased with gut retention time and declined with walleye dry weight. Maximum Da was estimated to be 79% of organic matter from food retained in the gut for 6 h.
Effects of reduced oxygen level on the mortality and hatching rate of Chondrostoma nasus embryos
Authors: Keckeis H. , Bauer‐Nemeschkal E. , Kamler E.
Published: April 2005

Exposure of embryos of Chondrostoma nasus to a strongly reduced oxygen content (about 10% of air saturation) enhanced mortality and depressed hatching success. Viable larvae hatched only from the controls and from the group exposed to reduced oxygen during the earliest embryogenesis (from fertilization to gastrula). In the groups exposed from gastrula to eyed stage and from eyed stage to hatching, a high percentage of fish hatched, but all were deformed and almost all died during the following 1–5 days. Hatching period was prolonged in the groups exposed to reduced oxygen content. At a spawning area C. nasus had deposited a large portion of eggs in areas of reduced oxygen content. On the other hand, eggs placed at the substratum surface were exposed to high predation pressure from Barbus barbus, Lota lota and ducks (Anas platyrhynchos). The trade‐off between predation pressure at the substratum surface and reduced oxygen conditions in the interstices resulted in a narrow space for successful development of embryos of this endangered rheophilic fish species under natural conditions.
Temperature‐ and light‐mediated predation by perch on vendace larvae
Authors: Huusko A. , Vuorimies O. , Sutela T.
Published: April 2005

The perch foraging pattern in a Finnish lake (64) N) was crepuscular and they moved into littoral areas at dusk and returned to deeper waters by dawn. Predation on vendace larvae was guided by environmental cues, mainly temperature and light periodicity, which affected the density and foraging activity of perch in the littoral area. The availability and the vulnerability of different food categories were both responsible for the perch diet. The hypothesis that perch have a generally decisive role in the regulation of vendace larval abundance through predation at the time of high vendace larvae concentration in the littoral area was not supported. We emphasize the need to evaluate biological phenomena, such as predator–prey relationships, in the light of the relevant physical variables, and to do so within appropriate time and space scales, instead of relying on indirect estimates of the predator and prey population abundance and using their reciprocity as evidence of the interaction.
Behavioural responses of benthic and pelagic Arctic charr to substratum heterogeneity
Authors: Mikheev V. N. , Adams C. E. , Huntingford F. A. , Thorpe J. E.
Published: April 2005

Responses to environmental heterogeneity were studied in laboratory‐reared offspring of two morphs of Arctic charr Salvelinus alpinus from Loch Rannoch, Scotland, one occupying the pelagic zone and feeding predominantly on zooplankton and the other being benthic in habit and feeding mainly on macroinvertebrates. When housed in groups in tanks with a black‐and white striped base, benthic charr demonstrated a clear preference for dark areas, whereas pelagic fish positioned themselves at random with respect to substratum colour. In general, pelagic charr were much less aggressive than benthic charr. In pelagic fish, neither spacing nor aggression was affected by the visual heterogeneity of the substrate. In contrast, benthic charr swam closer together and fought more when housed over a uniform as opposed to a non‐uniform substratum. The results are discussed in the context of habitat‐specific visual requirements and of an interaction between visual complexity and territoriality previously described for Atlantic salmon Salmo salar.
Sex ratio, spawning season and size at maturity of red bandfish in the western Aegean Sea
Authors: Stergiou K. I. , Economidis P. , Sinis A.
Published: April 2005

The red bandfish Cepola rubescens is characterized by a normal gonochoristic sexual organization. The overall male: female ratio did not differ significantly (x2=4.57, P<0.05) from the theoretical 1: 1. However, the male: female ratio differed with season and length class and these differences are most probably related to sexual differences in growth rate, natural mortality rate and energetic cost of reproduction. Red bandfish spawns over an extended period, from late spring to mid autumn, with larger females spawning earlier than smaller ones. Males reach maturity at a larger total length, 299 mm, and age, 2.6 years, than females, 219 mm and 1.9 years respectively, a fact most probably indicating the existence of social structure in red bandfish. Finally, red bandfish matures at a comparatively smaller length and age than other fish species.
Interindividual variations in feeding and growth in rainbow trout during restricted feeding and in a subsequent period of compensatory growth
Authors: Jobling M. , Koskela J.
Published: April 2005

Compensatory growth responses of rainbow trout Oncorhynchus mykiss were studied by examining food intake and growth of individual fish held within groups that were switched between regimes that involved full and restricted feeding. Restricted feeding led to marked interindividual variability in food intake, probably as a result of the establishment of feeding hierarchies. This disparity in food acquisition was reflected in highly heterogeneous growth amongst the fish fed low rations. When fish were transferred from restricted to full rations, they became hyperphagic and displayed high rates of growth. Growth compensation was most marked amongst those fish which had shown the poorest growth during the period of feed restriction. These results suggest that the feeding hierarchies established under feed restriction did not persist, but were rapidly broken down when food became increasingly available, enabling the previously suppressed fish to gain access to food and to display rapid growth.
Computing expected reproductive success of female Atlantic salmon as a function of salmon size
Authors: Mangel M.
Published: April 2005

A method is described for determining the expected reproductive success (gonadal mass of a returning fish times the probability of surviving to return) and expected fecundity of salmonids as a function of smolt size. Application of the method requires data relating (i) return weight and smolt size; (ii) probability of survival and smolt size; (iii) probability of return after one or two sea winters and smolt size; and (iv) gonads and return weight. Although there exists no published data set that contains all of this information, it is possible to piece together enough information from published sources on female Atlantic salmon to demonstrate the feasibility of the method, with the goal of encouraging the publication of datasets that will allow meaningful calculations for a single river. Thus, one should not expect general predictions about Atlantic salmon, but once local conditions are taken into account, it will be possible to predict the relationships between smolt size and expected fecundity or expected reproductive success.
Diet, growth and reproduction of the Arctic charr in a high alpine lake
Authors: Cavalli L. , Chappaz R.
Published: April 2005

The Arctic charr of Muzelle lake, at 2105 m in the Oisans massif (French Alps) feed most actively, essentially on Chironomidae, during the 6 or 7 weeks following the melting of the ice. The period of maximum growth corresponds to the time when food availability is at its highest, and it does not overlap with the period of maximum temperatures. Males and females mature at age 3 years but only half of the females of age 3 years spawn each year. This ratio of spawning females is constant from 3 to 6 years, the latter being maximum age observed in this lake. Each female spawns only twice at the most during its lifetime.
Geographic variation in the grey mullet: a geometric morphometric analysis using partial warp scores
Authors: Corti M. , Crosetti D.
Published: April 2005

Multivariate examination of partial warps allowed the description of shape differences characterizing each of 10 populations of Mugil cephalus. Patterns of morphometric distances (overall, uniform and non‐uniform) among samples suggested that morphometry in part reflected the geographic origin of the samples. However, comparisons with allozymes and mtDNA provided no exhaustive evidence for a pure phylogenetic cause for the observed patterns of geographic Variation.
Natural reproduction of anadromous rainbow trout in Norway
Authors: Sægrov H. , Hindar K. , Urdal K.
Published: April 2005

Six naturally reproduced 0+ rainbow trout were caught in a Norwegian river in 1994. This is the second report and first recorded sample of descendants from anadromous parents found in a Norwegian river. If this is not a unique event, the finding bodes ill for future conservation of native anadromous Salmonids.
Gymnotiform fish: an important component of Amazonian fioodplain fish communities
Authors: Crampton W. G. R.
Published: April 2005

Estimates of the density, biomass and species diversity of fish from floating meadow and flooded forest habitats suggest that gymnotiform fish constitute an important component of Amazonian flood plain fish faunas. Electric eels, Electrophorus electricus are unexpectedly abundant within Varzea forest.
Variation in mitochondrial DNA and post‐glacial colonization of north western Europe by brown trout
Authors: Hynes R. A. , Ferguson A. , McCann M. A.
Published: April 2005

A purified mitochondrial DNA (mtDNA) probe was used to examine restriction fragment length polymorphisms produced by six restriction enzymes (Xba I, Eco RV, Ava II, HinfI, Hae III, Mbo I) in 915 brown trout from western Europe. A total of 20 composite haplotypes were found with one to seven haplotypes in individual populations. Icelandic trout samples from north, south, east, and west coast drainages showed only a single common haplotype in contrast to the high level of polymorphism found in Irish and Scottish populations. The phylogeny of mtDNA haplotypes and the pattern of haplotype distribution suggests that post‐glacial colonization of brown trout in NW Europe was more complex than the dual colonization model which has been proposed on the basis of differential LDH‐5* allele distribution. For example, Lough Melvin (Ireland) appears to have been independently
Triploid progeny from a female Atlantic salmon × brown trout hybrid backcrossed to a male brown trout
Authors: Dannewitz J. , Jansson H.
Published: April 2005

A female Atlantic salmon × brown trout hybrid was backcrossed to a male brown trout. Electrophoretic analysis of diagnostic enzymes showed that the progeny were triploid. However, a few individuals were partially diploid.
The effect of hypoxia on red blood cells of flounder: a morphologic and autoradiographic study
Authors: Soldatov A. A.
Published: April 2005

Flounders were maintained in water with low oxygen content (2.6–2.7 mg 1 ‐ 1, 30% saturation) for 2, 6 and 24 h. Hypoxia enhanced the proliferation and differentiation process among juvenile red blood cells (RBCs) in the pronephros. It was accompanied by an increase in RBCs number in blood by up to 37% (P<0.01) 6 h after adaptation. The number of dividing mature RBCs in blood during the initial period of adaptation (2 h) was 2.5 times greater (P<0.001) than in the control group. It was shown (in vitro) that the serum contained factors stimulating division of mature RBCs in blood during adaptation to hypoxia.
Relative production of Atlantic salmon from fluvial and lacustrine habitats estimated from analyses of scale characteristics
Authors: Dempson J. B. , O'Connell M. F. , Shears M.
Published: April 2005

Empirical and back‐calculated growth of Atlantic salmon parr were compared between fish reared in fluvial and lacustrine habitats of Conne River, Newfoundland. Length at age was significantly higher for lacustrine parr. Various classification and maximum likelihood estimators indicated that 75% or more of the fish used lakes for rearing. Lacustrine use is another aspect of the inherent variability and plasticity of Atlantic salmon life‐history traits. As most Newfoundland river systems include lakes, estimates of regional spawning targets and potential smolt production will need to take lake habitat into account.
Microhabitat use and diet of 0+ cyprinid fishes in a lentic, regulated reach of the River Great Ouse, England
Authors: Garner P.
Published: April 2005

In the River Great Ouse, 0+ roach, bream, chub, bleak and gudgeon were each divided into three‘ ecospecies’ on the basis of their morphology: young larvae, old larvae and juveniles. Ecologically similar species were positively associated and dissimilar species were negatively associated. All ecospecies, except juvenile bleak preferred water < 1 m deep, within 6 m of the bank with some plant cover. Habitat use was similar for all species. It is suggested that this habitat offers increased growth rate, reduced predation risk and increased food abundance to all species, and that species overlap is due to complementary habitat use rather than aggregation. During the early larval period all species fed predominantly upon rotifers and diatoms. During the late larval period there was a switch to Cladocera, primarily Chydoridae and Ceriodaphnia sp., and chironomid larvae. Species‐specific dietary selection was evident during the juvenile period, with roach feeding primarily upon aufwuchs, bream upon Cladocera, chub upon Diptera, and gudgeon upon Copepoda.
Lake Tana large barbs: phenetics, growth and diversification
Authors: Mina M. V. , Mironovsky A. N. , Dgebuadze Yu.
Published: April 2005

Among the Lake Tana large barbs of about 10 cm SL only representatives of the‘ acute’morphotype can be distinguished, in the size range 10–20 cm SL‘ bigmouth big eye’ can be identified also. As for the rest, very few individuals can be confidently affiliated with a particular morphotype most of them looking like‘ intermedius’. Even within the range of 20–30 cm SL some individuals are still difficult to identify. Principal component analysis of cranial characters revealed discrete groups of morphotypes. Differences in both external and cranial characters of the morphotypes result from divergence which is most pronounced when fish are 4–5 years old and 20–25 cm SL. This divergence cannot be related exclusively with differences in the growth rates of individuals representing different morphotypes. Differences in food composition between the morphotypes probably increase in parallel with their morphological divergence. Differences between the morphotypes in the lateral line (11) and the gill rakers (Sb) counts were revealed using ANOVA. Comparison of the Lake Tana Barbus complex of forms with that previously known from Lake Lanao (Philippines) suggests that in both lakes the different forms arose sympatrically but that sympatric speciation in Lake Lanao has advanced further than in Lake Tana.
Early development of milkfish: effects of salinity on embryonic and larval metabolism, yolk absorption and growth
Authors: Swanson C.
Published: April 2005

During embryogenesis of Chanos chanos, more than half of the yolk was consumed and the majority of it was converted into larval tissue. Salinity affected both yolk absorption and embryonic and larval growth. Larvae hatched in 20% had larger yolk reserves but were smaller and grew more slowly than larvae in 35 and 50%. Larvae hatched in 35 and 50% had equal amounts of yolk but those from 35% were larger. Oxygen consumption rates increased during development (from 0.06 ± 0.01 μl O2 egg–1 h–1 by blastulae to 0.37 ± 0‐01 μl O2 egg–1 h–1 by prehatch embryos and 0–43 ± 0–03 μl O2 larva –1 h –1 by newly‐hatched larvae) and were significantly affected by salinity. Eggs and yolk‐sac larvae incubated in 35% consumed more oxygen than those in the low and high salinities. Salinity affected both the rate and pattern of yolk utilization but salinity‐related differences in metabolism, yolk absorption, and growth were not related directly to the osmotic gradient. Low salinity retarded yolk absorption while high salinity reduced yolk utilization efficiencies. Differences in oxygen consumption rates were probably related to variations in the relative amounts of metabolically active embryonic and larval tissue and/or higher activity levels rather than differential osmoregulatory costs. 35% is probably the most suitable salinity for incubation and larval rearing of milkfish.
Effects of spatial distribution of light on prey ingestion of Atlantic halibut larvae
Authors: GULBRANDSEN J.
Published: April 2005

The hypothesis that light distribution affects prey distribution and in turn influences prey ingestion was tested on Atlantic halibut larvae Hippoglossus hippoglossus. Low intensity concentrated light produced swarms of Artemia sp., but did not affect the distribution of Brachionus plicatilis. Low intensity diffused light, however, did not create swarms with either prey. As a consequence, halibut larvae ingested more Brachionus than Artemia in concentrated light, but not in diffused light. Due to differences in dry weight between Artemia and Brachionus, ingested biomass values were indistinguishable under the two experimental regimes.The term‘ population ingestion value’ is introduced as an expression for the ingestive capability of the population as a whole.
The lipid composition of two species of serrasalmid fish in relation to dietary polyunsaturated fatty acids
Authors: Henderson R. J. , Tillmanns M. M. , Sargent J. R.
Published: April 2005

The lipid composition of two species of Serrasalmid fish with different natural feeding habits were compared in relation to the polyunsaturated fatty acids (PUFA) supplied in their diets. Mylossoma aureum, a herbivorous piranha, was maintained on oatmeal flakes in which : 2(n‐6) and : 3(n‐3) were the only PUFA and accounted for 40–8 and 1.2%, respectively of dietary fatty acids. Serrasalmus nattereri, the carnivorous red piranha, was fed mosquito larvae containing .0‐33.4% of their total fatty acids as : 2(n‐6)+18 : 3(n‐3) and 4.9‐8.5% as 20 : 4(n‐6)+20 : 5(n‐3). The two species had similar lipid class compositions in liver, brain, viscera and carcass, except that lipids from M. aureum were generally richer in triacylglycerols. In both species, visceral and carcass lipid contained high levels of triacylglycerols whose principal PUFA was : 2(n‐6). In M. aureum the major PUFA in liver total lipid and triacylglycerols was : 2(n‐6) whilst the major PUFA in liver phospholipids were : 4(n‐6) and : 5(n‐6), with : 6(n‐3) being a minor component. The level of : 6(n‐3) in ethanolamine glycerophospholipids was significantly greater in brain than liver of M. aureum. Although absent from dietary lipid, : 6(n‐3) was the major PUFA in phosphatidylcholine and ethanolamine glycerophospholipids from both the liver and brain of S, nattereri. In both species, the ratio of (n‐6)/(n‐3)PUFA was consistently lower in tissue lipids than in dietary lipids. The results are consistent with (i) the herbivorous M. aureum converting dietary C18 PUFA to their C20 and C22 homologues, (ii) the carnivorous S, nattereri forming : 6(n‐3) from either 18:3(n‐3) or 20: 5(n‐3) and (iii) both species selectively desaturating and elongating (n‐3) rather than (n‐6) PUFA.
The performance of all‐female diploid and triploid Atlantic salmon smolts on transfer together to sea water
Authors: McCarthy I. D. , Carter C. G. , Houlihan D. F. , Johnstone R. , Mitchell A. I.
Published: April 2005

On transfer to sea water for 45 days, the return of appetite was later and growth rates tended to be lower for triploid Atlantic salmon, Salmo salar, reared together with diploid Atlantic salmon. All mortalities comprised of triploid salmon (29%) and were attributable to failed smolt syndrome. No correlation was found between the growth of diploid or triploid fish in fresh water and their subsequent growth on transfer to sea water.
Activity of cytochrome c oxidase and lactate dehydrogenase in muscle tissue of slow growing (lower modal group) and fast growing (upper modal group) Atlantic salmon
Authors: Nathanailides C. , Stickland N. C.
Published: April 2005

Fast growing Atlantic salmon (upper modal group) exhibit a higher activity of muscle cytochrome c oxidase (CCO) and lactate dehydrogenase (LDH) than the slow growing salmon (lower modal group). The ratios of CCO/LDH activity, indicate a higher aerobic/anaerobic metabolic potential of the axial muscle in the upper modal group.
Populations and assemblages of parasites in hake, Merluccius gayi, from the southeastern Pacific Ocean: stock implications
Authors: George‐Nascimento M.
Published: April 2005

To assess fish stocks, the populations and community assemblages of metazoan parasites were compared in 1172 Chilean hake Merluccius gayi landed at two major ports, and caught during 1991–1992 in three major fishing areas off central Chile. At least two ecological stocks are suggested, based on consistent differences in parasitism between body length classes for Grillotia dollfusi, Hysterothylacium sp., Clestobothrium crassiceps and Aporocotyle wilhelmi. More use should be made of the information on whole parasite assemblages including, for example, patterns of co‐occurrence of parasite species. Univariate analyses on selected taxa in samples from different areas may show no differences because of the same prevalence or abundance for each parasite taxon, but opposite numerical arrangements of co‐occurring taxa in community assemblages would remain undetected.
Growth with seasonally varying temperatures: an expansion of the von Bertalanffy growth model
Authors: Fontoura N. F. , Agostinho A. A.
Published: April 2005

The von Bertalanffy growth function has limitations for describing the growth of fishes in seasonal climates. In the present work, a new equation is proposed where the growth parameter k is substituted by a function related to monthly water temperatures. The computer program GROWTHS was developed to fit and simulate the growth for seasonally varying temperatures. Examples for natural populations of Barbatula barbatula and Cottus gobio are presented.
Aluminium in the brain and heart of the rainbow trout
Authors: Exley C.
Published: April 2005

Tissue residue analysis and aluminium‐specific hifstochemistry demonstrated that the chronic exposure of rainbow trout to aluminium results in the systemic accumulation of aluminium and a distinct neuropathology in the brain. Aluminium was found associated with endothelial and epithelial surfaces including the cerebrovascular endothelium of the brain and the endothelium of the bulbus arteriosus of the heart. The potential for aluminium to compromise the barrier properties of membranes may underlie its known toxicity in fish.
Sublethal effects of the pesticide Diazinon on olfactory function in mature male Atlantic salmon parr
Authors: Moore A. , Waring C. P.
Published: April 2005

Diazinon, an organophosphate pesticide, had a sublethal effect on the olfactory system of mature male Atlantic salmon parr. The olfactory responses of the parr to prostaglandin F2a (PGF2a) were studied after exposure of the epithelium to different concentrations of Diazinon in water. Electrophysiological recordings from the epithelium indicated that the responses to this prostaglandin were significantly reduced at nominal concentrations as low as 1.0μg l−1 and the threshold of detection was reduced 10‐fold at 2.0 μg 1−1 . Mature male salmon parr exposed for a period of 120 h to Diazinon (nominal concentrations 0.3, 0.8, 1.7, 2.7, 5.6, 13, 28 and 45 μg 1 −1) also had significantly reduced levels of the reproductive steroids, 17,20β‐dihydroxy‐4‐pregnen‐3‐one, testosterone and gonadotrophin II in the blood plasma after priming with ovulated female salmon urine. Both prostaglandin F2a and ovulated female urine are known to have important roles in synchronizing reproductive physiology and behaviour in salmonids as well as other fish species. The results are therefore discussed in relation to the possible sublethal effects of Diazinon on reproduction in the Atlantic salmon and possible effects on populations of salmonids.
The effect of domestication on some life history traits of sea trout and Atlantic salmon
Authors: Petersson E. , Jaurvi T. , Steffner N. G. , Ragnarsson B.
Published: April 2005

During the period 1968–1991, certain morphological traits of Atlantic salmonSalmo salarand sea troutS. truttahave been recorded regularly at the hatchery at Älvkarleby, central Sweden. Total body length, weight (for females both before and after stripping), number of eggs, egg size and date of ovulation. A smaller data set for fish marked and released as smolts, providing information about total body length of released smolts, time spent at sea and body size of the recovered adults, was also available for analysis. According to theory and empirical data, the process of artificial breeding results in an evolutionary divergence of the cultured strain from the wild phenotypic norm. The reason for such a divergence is that both natural and sexual selection pressures are altered or relaxed during the process of artificial breeding, as well as random genetic processes, such as founder effects and in‐ and outbreeding. A path analysis of both species and sexes revealed that the size of the released smolts had increased during the study period. Time spent in sea has decreased for both female and male sea trout, but not for Atlantic salmon. Adult body size for female and male trout have increased as well as female trout condition factor. The increase found in egg size of both species was greater for the salmon than for the trout, indicating that female salmon invest more in egg size with increasing body size. These results support the view that domestication probably has a significant and selective impact on the life history traits of the two salmonid species studied.