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Seasonality of metazoan ectoparasites in marine European flounder Platichthys flesus (Teleostei: Pleuronectidae)

cavaleiro, fi; santos, mj
Fonte: Universidade do Porto Publicador: Universidade do Porto
Tipo: Artigo de Revista Científica
ENG
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Seasonal occurrence of metazoan ectoparasites is described for the first time in marine European flounder. Platichthys flesus (L.). The parasitofauna, ill this study monitored during I Was found to be similar to that previously recorded for flounder. Moreover, specimens of Caligus sp. Muller, 1785 bind Lepeophtheirus performs (Copepoda: Caligidae), Acanthochondria cornuta (Copepoda: Chondracanthidae), Holobomolochus confusus (Copepoda: Bomolochidae) Mid Nerocila orbignyi (Isopoda: Cymothoidae), and also, a praniza larva (Isopoda: Gnathiidae), were isolated. From these, L.pecotoralis and A. cornuta were the dominant parasites in all samples of flounder, while Caligus sp. H. confusus. N. orbignyi Mid the gnathiid praniza seemed to infect the flounder only occasionally. As far as the seasonality of infections is concerned, it differed considerably from that described for estuarine environments. Indeed, both prevalence and abundance of . pectoralis mid A. cornuta reached significant peaks in the summer, whereas the literature identifies the autumn as the season of maximum infection on estuarine flounder. Thus, the former period seems more favourable for the occurence of epizooties of L. pectoralis and A. cornuta in flounder culturing systems running on seawater and operated in the studied or similar environments.

Isolation, characterization and seasonal variations in the concentration of N-epsilon-(gamma-glutamyl)-lysine isodipeptide in the blood plasma of the winter flounder (Pseudopleuronectes americanus).

Squires, E J; Feltham, L A
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 01/03/1980 EN
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A ninhydrin-positive compound was isolated from the plasma of the winter flounder (Pseudopleuronectes americanus) and identified as the isodipeptide N-epsilon-(gamma-glutamyl)-lysine. Wide seasonal variations in plasma concentration of this compound are found in the male flounder, whereas it is present only in trace amounts in the plasma of the female flounder throughout the year. In the male flounder the plasma concentration of N-epsilon-(gamma-glutamyl)-lysine rises from January to a peak in May and June. It is during these latter months that the flounder spawn. After spawning, the plasma concentration of the isodipeptide decreases to low basal values in October. These changes in plasma concentration of N-epsilon-(gamma-glutamyl)-lysine may be related to changes in testes weight, spermatogenesis and spawning activity of the winter flounder.

Wild and Hatchery Populations of Korean Starry Flounder (Platichthys stellatus) Compared Using Microsatellite DNA Markers

An, Hye Suck; Byun, Soon Gyu; Kim, Yi Cheong; Lee, Jang Wook; Myeong, Jeong-In
Fonte: Molecular Diversity Preservation International (MDPI) Publicador: Molecular Diversity Preservation International (MDPI)
Tipo: Artigo de Revista Científica
Publicado em 09/12/2011 EN
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Starry flounder (Platichthys stellatus) is an important sport and food fish found around the margins of the North Pacific. Aquaculture production of this species in Korea has increased because of its commercial value. Microsatellite DNA markers are a useful DNA-based tool for monitoring the genetic variation of starry flounder populations. In this study, 12 polymorphic microsatellite DNA markers were identified from a partial genomic starry flounder DNA library enriched in CA repeats, and used to compare allelic variation between wild and hatchery starry flounder populations in Korea. All loci were readily amplified and demonstrated high allelic diversity, with the number of alleles ranging from 6 to 18 in the wild population and from 2 to 12 in the farmed population. A total of 136 alleles were detected at the 12 microsatellite loci in the two populations. The mean observed and expected heterozygosities were 0.62 and 0.68, respectively, in the hatchery samples and 0.67 and 0.75, respectively, in the wild samples. These results indicate lower genetic variability in the hatchery population as compared to the wild population. Significant shifts in allelic frequencies were detected at eight loci, which resulted in a small but significant genetic differences between the wild and hatchery populations (FST = 0.043...

A New PCR-Based Method Shows That Blue Crabs (Callinectes sapidus (Rathbun)) Consume Winter Flounder (Pseudopleuronectes americanus (Walbaum))

Collier, Jackie L.; Fitzgerald, Sean P.; Hice, Lyndie A.; Frisk, Michael G.; McElroy, Anne E.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 13/01/2014 EN
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Winter flounder (Pseudopleuronectes americanus) once supported robust commercial and recreational fisheries in the New York (USA) region, but since the 1990s populations have been in decline. Available data show that settlement of young-of-the-year winter flounder has not declined as sharply as adult abundance, suggesting that juveniles are experiencing higher mortality following settlement. The recent increase of blue crab (Callinectes sapidus) abundance in the New York region raises the possibility that new sources of predation may be contributing to juvenile winter flounder mortality. To investigate this possibility we developed and validated a method to specifically detect winter flounder mitochondrial control region DNA sequences in the gut contents of blue crabs. A survey of 55 crabs collected from Shinnecock Bay (along the south shore of Long Island, New York) in July, August, and September of 2011 showed that 12 of 42 blue crabs (28.6%) from which PCR-amplifiable DNA was recovered had consumed winter flounder in the wild, empirically supporting the trophic link between these species that has been widely speculated to exist. This technique overcomes difficulties with visual identification of the often unrecognizable gut contents of decapod crustaceans...

Characterization of Muscle-Regulatory Gene, MyoD, from Flounder (Paralichthys olivaceus) and Analysis of Its Expression Patterns During Embryogenesis

Zhang, Yuqing; Tan, Xungang; Zhang, Pei-Jun; Xu, Yongli
Fonte: Springer-Verlag Publicador: Springer-Verlag
Tipo: Artigo de Revista Científica
EN
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Specification and differentiation of skeletal muscle cells are driven by the activity of genes encoding members of the myogenic regulatory factors (MRFs). In vertebrates, the MRF family includes MyoD, Myf5, myogenin, and MRF4. The MRFs are capable of converting a variety of nonmuscle cells into myoblasts and myotubes. To better understand their roles in fish muscle development, we isolated the MyoD gene from flounder (Paralichthys olivaceus) and analyzed its structure and patterns of expression. Sequence analysis showed that flounder MyoD shared a structure similar to that of vertebrate MRFs with three exons and two introns, and its protein contained a highly conserved basic helix–loop–helix domain (bHLH). Comparison of sequences revealed that flounder MyoD was highly conserved with other fish MyoD genes. Sequence alignment and phylogenetic analysis indicated that flounder MyoD, seabream (Sparus aurata) MyoD1, takifugu (Takifugu rubripes) MyoD, and tilapia (Oreochromis aureus) MyoD were more likely to be homologous genes. Flounder MyoD expression was first detected as two rows of presomitic cells in the segmental plate. From somitogenesis, MyoD transcripts were present in the adaxial cells that give rise to slow muscles and the lateral somitic cells that give rise to fast muscles. After 30 somites formed...

Differential Expression Patterns of Crystallin Genes during Ocular Development of Olive Flounder (Paralichthys olivaceus)

Yang, Hyun; Lee, Young Mee; Noh, Jae Koo; Kim, Hyun Chul; Park, Choul Ji; Park, Jong Won; Hwang, In Joon; Kim, Sung Yeon; Lee, Jeong Ho
Fonte: Korean Society of Developmental Biology Publicador: Korean Society of Developmental Biology
Tipo: Artigo de Revista Científica
Publicado em /12/2012 EN
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Olive flounder Paralichthys olivaceus is one of the most widely cultured fish species in Korea. Although olive flounder receive attention from aquaculture and fisheries and extensive research has been conducted eye morphological change in metamorphosis, but little information was known to molecular mechanism and gene expression of eye development- related genes during the early part of eye formation period. For the reason of eyesight is the most important sense in flounder larvae to search prey, the screening and identification of expressed genes in the eye will provide useful insight into the molecular regulation mechanism of eye development in olive flounder. Through the search of an olive flounder DNA database of expressed sequence tags (EST), we found a partial sequence that was similar to crystallin beta A1 and gamma S. Microscopic observation of retinal formation correspond with the time of expression of the crystallin beta A1 and gamma S gene in the developmental stage, these result suggesting that beta A1 and gamma S play a vital role in the remodeling of the retina during eye development. The expression of crystallin beta A1 and gamma S were obviously strong in eye at all tested developing stage, it is also hypothesized that crystallin acts as a molecular chaperone to prevent protein aggregation during maturation and aging in the eye.

Locus Number Estimation of MHC Class II B in Stone Flounder and Japanese Flounder

Jiang, Jiajun; Li, Chunmei; Zhang, Quanqi; Wang, Xubo
Fonte: MDPI Publicador: MDPI
Tipo: Artigo de Revista Científica
Publicado em 13/03/2015 EN
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Members of major histocompatibility complex (MHC) family are important in immune systems. Great efforts have been made to reveal their complicated gene structures. But many existing studies focus on partial sequences of MHC genes. In this study, by gene cloning and sequencing, we identified cDNA sequences and DNA sequences of the MHC class II B in two flatfishes, stone flounder (Kareius bicoloratus) and homozygous diploid Japanese flounder (Paralichthys olivaceus). Eleven cDNA sequences were acquired from eight stone flounder individuals, and most of the polymorphic sites distributed in exons 2 and 3. Twenty-eight alleles were identified from the DNA fragments in these eight individuals. It could be deduced from their Bayesian inference phylogenetic tree that at least four loci of MHC class II B exist in stone flounder. The detailed whole-length DNA sequences in one individual were analyzed, revealing that the intron length varied among different loci. Four different cDNA sequences were identified from one homozygous diploid Japanese flounder individual, implying the existence of at least four loci. Comparison of the cDNA sequences to the DNA sequence confirmed that six exons existed in this gene of Japanese flounder, which was a common feature shared by Pleuronectiformes fishes. Our results proved the multi-locus feature of MHC class II B. The sequences we obtained would provide detailed and systematic data for further research.

Development and Validation of Single Nucleotide Polymorphism (SNP) Markers from an Expressed Sequence Tag (EST) Database in Olive Flounder (Paralichthys olivaceus)

Kim, Jung Eun; Lee, Young Mee; Lee, Jeong-Ho; Noh, Jae Koo; Kim, Hyun Chul; Park, Choul-Ji; Park, Jong-Won; Kim, Kyung-Kil
Fonte: Korean Society of Developmental Biology Publicador: Korean Society of Developmental Biology
Tipo: Artigo de Revista Científica
Publicado em /12/2014 EN
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To successful molecular breeding, identification and functional characterization of breeding related genes and development of molecular breeding techniques using DNA markers are essential. Although the development of a useful marker is difficult in the aspect of time, cost and effort, many markers are being developed to be used in molecular breeding and developed markers have been used in many fields. Single nucleotide polymorphisms (SNPs) markers were widely used for genomic research and breeding, but has hardly been validated for screening functional genes in olive flounder. We identified single nucleotide polymorphisms (SNPs) from expressed sequence tag (EST) database in olive flounder; out of a total 4,327 ESTs, 693 contigs and 514 SNPs were detected in total EST, and these substitutions include 297 transitions and 217 transversions. As a result, 144 SNP markers were developed on the basis of 514 SNP to selection of useful gene region, and then applied to each of eight wild and culture olive flounder (total 16 samples). In our experimental result, only 32 markers had detected polymorphism in sample, also identified 21 transitions and 11 transversions, whereas indel was not detected in polymorphic SNPs. Heterozygosity of wild and cultured olive flounder using the 32 SNP markers is 0.34 and 0.29...

Biomarkers of exposure and effect in the Brazilian flounder Paralichthys orbignyanus (Teleostei: Paralichthyidae) from the Patos Lagoon estuary (Southern Brazil).

Amado, Lílian Lund; Robaldo, Ricardo Berteaux; Monserrat, Laura Alicia Geracitano; Monserrat, José María; Bianchini, Adalto
Fonte: Universidade Federal do Rio Grande Publicador: Universidade Federal do Rio Grande
Tipo: Artigo de Revista Científica
ENG
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Biomarkers of exposure (liver metallothionein-like proteins content and catalase and glutathione S-transferase activities) and effect (liver lipoperoxidation and blood cell DNA damage) of contaminants were analyzed in the Brazilian flounder Paralichthys orbignyanus from the Patos Lagoon estuary (Southern Brazil). Flounders were collected for a year in two sites: ‘‘Coroa do Boi’’ (polluted site) and ‘‘Saco do Justino’’ (non-polluted site). Results indicated that micronucleated cells frequency was the best biomarker to distinguish flounders from the two sites. Taken together, data from DNA damage analyses (micronucleus test and comet assay) indicated that flounders from the non-polluted site efficiently repaired the DNA breaks, contrary to those from the polluted site, which probably had their DNA repair system inhibited or exhausted. Furthermore, data from enzyme activities (catalase and GST) and lipid peroxidation indicated that flounders from the polluted site were under oxidative stress in summer and autumn.

Hormone-induced ovulation, natural spawning and larviculture of Brazilian flounder Paralichthys orbignyanus (Valenciennes, 1839)

Sampaio, Luís André Nassr de; Robaldo, Ricardo Berteaux; Bianchini, Adalto
Fonte: Universidade Federal do Rio Grande Publicador: Universidade Federal do Rio Grande
Tipo: Artigo de Revista Científica
ENG
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Mature Brazilian flounders Paralichthys orbignyanus were captured in coastal southern Brazil and their reproduction in captivity was studied. Brazilian flounder will spawn naturally in captivity when the water temperature is around 23 1Cand14hof light is provided daily. Females were induced for ovulation and hand stripping using human chorionic gonadotropin, luteinizing hormone-releasing hormone analogue or carp pituitary extract. There was no need to inject males, as running milt was observed during the spawning season. Fertilization and hatching rates were above 80% independent of the hormone used. Notochord length at hatching was 2.18 _ 0.07mm for larvae hatching from naturally spawned eggs. Larvae were reared in salt water (30^35 g L_1) at 24 1C and under continuous illumination. Larviculture was with green water (Tetraselmis tetrathele 50 _ 104 cellsmL_1). Rotifers (10^20 indmL_1) were o!ered as ¢rst food 3 days after hatching and gradually replaced by Artemia nauplii (0.5^ 10 ind mL_1). Larvae settled to the bottom 20 days after hatching and completed metamorphosis within a week after that. The total length for newly metamorphosed juveniles was 12.9 _ 2.2mm and the mean survival was 44.8%. The results demonstrate the feasibility of producing Brazilian flounder¢ngerlings for stock enhancement or grow-out purposes.

Potential environmental and host gender influences on prevalence of Haemogregarina platessae (Adeleorina: Haemogregarinidae) and suspected Haemohormidium terraenovae (incertae sedis) in Brazilian flounder from the Patos Lagoon Estuary, Southern Brazil

Davies, Angela; Amado, Lílian Lund; Cook, Richard; Bianchini, Adalto; Eiras, Jorge Costa
Fonte: Universidade Federal do Rio Grande Publicador: Universidade Federal do Rio Grande
Tipo: Artigo de Revista Científica
ENG
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373.5322%
Flounder, Paralichthys orbignyanus (Valenciennes), were captured in polluted and non-polluted sites within the Patos Lagoon Estuary, southern Brazil, over four seasons. Blood films showed a high prevalence of infection with a haemogregarine, or mixed parasitaemias of this and an organism resembling Haemohormidium terraenovae So, 1972. Haemogregarine gamont stages conformed to existing descriptions of Desseria platessae (Lebailly, 1904) Siddall, 1995 from flatfishes, but intraerythrocytic division of meronts was observed, leading to the recommendation for nomenclatural correction, placing the haemogregarine in the genus Haemogregarina (sensu lato) Danilewsky, 1885. Statistical analyses suggested that although sample sizes were small, infections with meront stages, immature and mature gamonts were all influenced by site, and possibly therefore, by pollution. Season also appeared to determine likelihood of infection with meronts and immature gamonts, but not mature gamonts, while adult fish gender apparently affected infection with immature and mature gamonts, but not meronts. The H. terraenovaelike organism exhibited unusual extracellular forms and did not match closely with the type description of H. terraenovae; precise identification was therefore difficult. Data analyses suggested that parasitism by this organism was influenced by site and fish gender...

Salinity effects on osmoregulation and growth of the euryhaline flounder Paralichthys orbignyanus

Sampaio, Luís André Nassr de; Bianchini, Adalto
Fonte: Universidade Federal do Rio Grande Publicador: Universidade Federal do Rio Grande
Tipo: Artigo de Revista Científica
ENG
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The flounder, Paralichthys orbignyanus, is found in coastal and estuarine waters of the Western South Atlantic Ocean. It is being considered for aquaculture due to its high market price and wide tolerance to environmental factors such as salinity, pH, and nitrogenous compounds. The objective of this study was to characterize the ionic and osmotic regulation of P. orbignyanus over the range of its tolerated ambient salinities (0–40x) and to evaluate the survival and growth in freshwater (0x) and seawater (30x) over 90 days. After 15 days of exposure to different salinities (0x, 10x, 20x, 30xand 40x), plasma osmolality and ionic (Na +, Cl _, K+ and Ca2 + ) concentrations slightly increased with salinity. The isosmotic point was estimated as 328.6 mOsm kg _ 1 H2O and corresponded to 10.9xsalinity. After 90 days, survival was similar in freshwater and seawater, but osmo- and ionoregulation was significantly affected in freshwater and flounders reared in this medium showed a lower growth rate than those reared in seawater. Based on the results from this study, P. orbignyanus can be characterized as a marine/estuarine euryhaline teleost capable of hyper/ hypo iono- and osmoregulation over the fluctuating salinity regime faced by this species in the environment. Furthermore...

The type I antifreeze protein gene family in Pleuronectidae

Nabeta, Kyra Keiko
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado Formato: 1850815 bytes; application/pdf
EN; EN
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Antifreeze proteins (AFPs) protect marine teleosts from freezing in icy seawater by binding to nascent ice crystals and preventing their growth. It has been suggested that the gene dosage for AFPs in fish reflects the degree of exposure to harsh winter climates. The starry flounder, _Platichthys stellatus_, has been chosen to examine this relationship because it inhabits a range of the Pacific coast from California to the Arctic. This flatfish is presumed to produce type I AFP, which is an alanine-rich, amphipathic alpha-helix. Genomic DNA from four starry flounder was Southern blotted and probed with a cDNA of a winter flounder liver AFP. The hybridization signal was consistent with a gene family of approximately 40 copies. Blots of DNA from other starry flounder indicate that California fish have far fewer gene copies whereas Alaska fish have far more. This analysis is complicated by the fact that there are three different type I AFP isoforms. The first is expressed in the liver and secreted into circulation, the second is a larger hyperactive dimer also thought to be expressed in the liver, and the third is expressed in peripheral tissues. To evaluate the contribution of these latter two isoforms to the overall gene signal on Southern blots...

Juvenile nursery colonization patterns for the European flounder (Platichthys flesus): A latitudinal approach

Martinho, Filipe; van der Veer, Henk W.; Cabral, Henrique N.; Pardal, M. A.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica
ENG
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In this work, we analysed the latitudinal trends in the nursery habitat colonization processes of the European flounder (Platichthys flesus). This was accomplished by estimating the duration of the pelagic and metamorphic stages, aswell as the duration of the spawning period, in several nursery areas across its geographical distribution range in the European Atlantic Coast: Mondego estuary (Portugal), Vilaine estuary (France), Slack estuary (France), Wadden Sea (Netherlands) and the Sørfjord (Norway). All juvenile flounders were captured with beam trawls in June/July 2010, and otolith microstructure was used to determine the duration of each stage by means of daily growth increments. The pelagic and metamorphic stages were longer at the middle of the distribution range, and lasted in total up to two months after hatching. The spawning period occurred between mid- January and early-July over the species' distribution range, with a time lapse of nearly two months between the Mondego estuary and the Sørfjord, as a consequence of warmer water temperature earlier in the season in southern areas. In general, total length of the captured fish showed a latitudinal cline between the northernmost and southernmost sampling sites, with higher values at the middle of the distribution range. The results also suggested the existence of a countergradient growth compensation mechanism in the northernmost populations. Apart from temperature...

Movement of summer flounder (Paralichthys dentatus) in relation to hypoxia in an estuarine tributary

Miller, Margaret
Fonte: University of Delaware Publicador: University of Delaware
Tipo: Tese de Doutorado
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Targett, Timothy E.; Estuarine waters generally provide favorable physiochemical and biological conditions for early growth and survival of ecologically and economically important fishes. However, given their close proximity to expanding urban and rural coastal populations, estuaries are especially susceptible to the threat of increased nutrient loading and may contain areas of low dissolved oxygen (DO), or hypoxia. The present study looked at the effects of hypoxia on movement of estuary-dependent juvenile and adult summer flounder (Paralicthys dentatus). Summer flounder were captured from Indian River Bay, Delaware, surgically implanted with Vemco V7-4L acoustic tags, and released into Pepper Creek, a tributary of Indian River Bay that experiences diel-cycling hypoxia. Overall, 17 juveniles and 8 adult summer flounder were released into Pepper Creek during September in 2007 and 2008, and July in 2009. Vemco VR2 acoustic receivers and YSI 600XLM multi-parameter sondes were deployed along the longitudinal axis of Pepper Creek to capture the spatial and temporal dynamics of summer flounder movement in relation to hypoxia. Individual fish tracks were plotted on spatiotemporal DO contour plots using MATLAB software and analyzed with respect to the following environmental variables: DO...

Diel-cycling hypoxia and pH impacts on juvenile summer flounder growth and survival

Davidson, Max I.
Fonte: University of Delaware Publicador: University of Delaware
Tipo: Tese de Doutorado
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Targett, TImothy E.; A series of laboratory experiments was conducted to determine the impact of diel-cycling dissolved oxygen (DO) and pH on young-of-the-year summer flounder (Paralichthys dentatus). Flounder were exposed to two cycling DO levels (extreme = 1-11 mg O2 l-1 ; moderate = 3-9 mg O2 l-1 ), two cycling pH levels (extreme = 6.8-8.1; moderate = 7.2-7.8), and a constant normoxia (7.5 mg O2 l -1 ) & pH (7.5) control treatment in a fully crossed 3X3 experimental design at 25°C. DO and pH levels were chosen to reflect summertime conditions in shallow estuarine nursery habitat. Growth rate, overall change in mass, was significantly reduced in fish exposed to the most extreme diel-cycling hypoxia, across all pH treatments, throughout the course of 20 d experiments. No consistent growth detriment was observed in the other treatments, indicating a) that a moderate DO cycle has little or no impact on growth and b) that pH has neither an independent nor interactive effect with hypoxia on growth rate. In a series of experiments to examine growth rate recovery and acclimation, flounder experienced an initial growth rate detriment when subjected to extreme diel-cycling hypoxia and pH for 10 days, but then exhibited growth rate recovery (growth returned to control levels) when exposed to static normoxia and normal pH conditions the following 10 days. Flounder did not exhibit growth rate acclimation when subjected to extreme diel-cycling hypoxia and pH for an extended period...

Valine substituted winter flounder 'antifreeze': preservation of ice growth hysteresis

Haymet, A D J; Ward, Leanne G; Harding, Margaret; Knight, Charles A
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
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Three mutant polypeptides of the type 1 37-residue winter flounder 'antifreeze' protein have been synthesized. All four threonine residues in the native peptide were been mutated to serine, valine and glycine respectively and two additional salt bridges were incorporated into the sequences in order to improve aqueous solubility. The peptides were analyzed by nanoliter osmometry, the 'ice hemisphere' test, the 'crystal habit' test, measurement of ice growth hysteresis and CD spectroscopy. While the valine and serine mutants retain the α-helical structure, only the valine mutant retains 'antifreeze' activity similar to that of the native protein. These data show that the threonine hydroxyl groups do not play a crucial role in the accumulation of the native 'antifreeze' protein at the ice/water interface and the inhibition of ice growth below the equilibrium melting temperature.

Winter Flounder "Antifreeze" Proteins: Synthesis and Ice Growth Inhibition of Analogs that Probe the Relative Importance of Hydrophobic and Hydrogen-Bonding Interactions

Haymet, A D J; Ward, Leanne G; Harding, Margaret
Fonte: American Chemical Society Publicador: American Chemical Society
Tipo: Artigo de Revista Científica
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Two series of mutant polypeptides of the type I, 37-residue winter flounder 'antifreeze' protein have been synthesized and analyzed by nanoliter osmometry, the 'ice hemisphere' test, measurement of ice growth hysteresis and circular dichroism (CD) spectroscopy. In series 1 peptides the central two threonines and all four threonines of the native protein were mutated to serine. In series 2 peptides two additional salt bridges (K7, E11 and K29, E33) were incorporated, and all four threonine residues in this sequence were mutated simultaneously to each of serine, valine, alanine, and glycine, respectively. The CD studies showed that all mutants are 100% helical in structure at low temperature, except for the glycine derivative which was estimated to be 70% α-helical. Dilute solutions of serine-substituted series 1 peptides showed no detectable, nonbasal faceting, or hysteresis behavior, indicating either no or extremely weak interaction with ice. The analogous serine-substituted mutant in series 2, as well as the glycine derivative, displayed unfaceted growth and showed no hysteresis. Hysteresis values, ice growth patterns, and the helicity measurements showed that the additional salt bridges present in series 2 peptides do not alter significantly the properties of the protein. The valine-substituted mutant gave a distinct etching pattern in which polypeptide accumulates on the {2 0 2 1 } plane of ice 1h...

The effect of hydrophobic analogues of the type I winter flounder antifreeze protein on lipid bilayers

Tomczak, Melanie M; Hincha, Dirk K; Crowe, John H; Harding, Margaret; Haymet, A D J
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
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The effect of four synthetic analogues of the 37-residue winter flounder type I antifreeze protein (AFP), which contain four Val, Ala or Ile residues in place of Thr residues at positions 2, 13, 24 and 37 and two additional salt bridges, on the binary lipid system prepared from a 1:1 mixture of the highly unsaturated DGDG and saturated DMPC has been determined using FTIR spectroscopy. In contrast to the natural protein, which increases the thermotropic phase transition, the Thr, Val and Ala analogues decreased the thermotropic phase transitions of the liposomes by 2.2°C, 3.4°C and 2.4°C, while the Ile analogue had no effect on the transition. Experiments performed using perdeuterated DMPC showed that the Ala and Thr peptides interacted preferentially with the DGDG in the lipid mixture, while the Val peptide showed no preference for either lipid. The results are consistent with interactions involving the hydrophobic face of type I AFPs and model bilayers, i.e. the same face of the protein that is responsible for antifreeze properties. The different effects correlate with the helicity of the peptides and suggest that the solution conformation of the peptides has a significant role in determining the effects of the peptides on thermotropic membrane phase transitions.

Determinação de idades e crescimento do linguado branco Paralichthys patagonicus (Jordan, 1889) no sul do Brasil; Age and growth of the white flounder Paralichthys patagonicus (Jordan, 1889) in southern Brazil

Araújo, Júlio Neves de; Haimovice, Manuel
Fonte: Universidade de São Paulo. Instituto Oceanográfico Publicador: Universidade de São Paulo. Instituto Oceanográfico
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Formato: application/pdf
Publicado em 01/01/2000 POR
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A idade e o crescimento do linguado-branco Paralichthys patagonicus (Jordan, 1889) foram estudados a partir de amostras obtidas da pesca comercial no sul do Brasil entre 1989 e 1991. As idades foram determinadas sobre cortes transversais de otólitos de 460 exemplares. A análise do tipo de bordo e dos incrementos marginais dos otólitos mostrou que, a cada ano ocorre a formação de uma zona translúcida e uma zona opaca nos otólitos. As "remeas atingem maiores tamanhos e idades (630 mm, 13 anos) do que os machos (527 mm, 11 anos). Os parâmetros da equação de von Bertalanffy que representaram o crescimento em comprimento total das remeas foram: CT∞,= 623,0 mm, K= 0,279 e to= -0,243 anos; dos machos: CT∞,= 534,1 mm, K= 0,214 e t o = -1,589 anos e dos sexos agrupados: CT∞, = 609,1 mm, K = 0,255 to = - 0,462 anos. Os incrementos anuais em peso por idades aumentam até o final do quarto ano de vida quando a maioria já atingiu a primeira maturação sexual e ambos sexos alcançaram cerca de 30% do peso e 70% do comprimento assintóticos. Esta espécie é susceptível à sobrepesca de crescimento porque o redirecionamento do metabolismo do crescimento somático para a reprodução é gradativo e o potencial de crescimento após a maturação sexual é relativamente alto.; Age and growth of the white flounder Paralichthys patagonicus (Jordan...