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David L Taylor - One of the best experts on this subject based on the ideXlab platform.

  • effect of temperature on the functional response and foraging behavior of the sand shrimp crangon septemspinosa preying on juvenile winter Flounder pseudopleuronectes americanus
    Marine Ecology Progress Series, 2003
    Co-Authors: David L Taylor, Jeremy S Collie
    Abstract:

    Predator-prey dynamics between the sand shrimp Crangon septemspinosa and juvenile winter Flounder Pseudopleuronectes americanus were examined in laboratory experiments to assess the joint effects of varying prey density and temperature on shrimp foraging behavior and Flounder mortality. The functional response of shrimp to 6 densities of Flounder was determined at 2 tempera- tures (10 and 16°C). The behavioral mechanisms underlying the shrimp's functional response were quantified with visual observations and compared to the foraging parameters predicted by continu- ous-time functional response models. Shrimp consumption rates increased significantly with increas- ing Flounder density, irrespective of water temperature. At low Flounder densities, however, signifi- cantly more Flounder were consumed at 16°C than at 10°C. Analysis of proportional mortality of Flounder across prey density and general functional response models revealed a sigmoidal, Type III functional response at 10°C, and a hyperbolic, Type II functional response at 16°C. Model parameter estimates and visual observations of shrimp foraging behavior suggest that the variable functional responses at different temperatures are the result of cold temperatures decreasing predator activity at low Flounder densities, and conversely, shrimp maintaining high attack rates at low Flounder densities when exposed to warm temperatures. These findings indicate that shrimp are capable of driving Flounder populations to local extinction during warm water conditions. The recent warming trend experienced in northwest Atlantic estuaries, and its impact on trophic dynamics, may therefore explain the failure of the winter Flounder stocks to recover in these areas.

  • size dependent predation on post settlement winter Flounder pseudopleuronectes americanus by sand shrimp crangon septemspinosa
    Marine Ecology Progress Series, 2003
    Co-Authors: David L Taylor
    Abstract:

    Juvenile flatfish that are large-at-age are assumed to have a survival advantage because of a reduction in predator-induced mortality (bigger-is-better hypothesis), but this general- ization is largely unsubstantiated in fisheries research. This study examined size-dependent preda- tion on post-settlement winter Flounder Pseudopleuronectes americanus by the sand shrimp Crangon septemspinosa, and the interactive effects of Flounder density and water temperature on the preda- tor-prey interaction. Shrimp were visually observed foraging on Flounder, and the major elements of the 'predation sequence' were quantified, from which the susceptibility and gross vulnerability of Flounder were estimated. Flounder susceptibility generally decreased with increasing fish size until a complete refuge from shrimp predation was attained at sizes > 25 mm total length (TL). The gross vulnerability of Flounder to shrimp predation was dome-shaped when analyzed graphically with respect to prey size. At the extremes of the vulnerability response curve, small Flounder (8 to 12 mm TL) benefited from a decreased rate of encounters with shrimp predators, whereas large Flounder (18 to 22 mm TL) profited from superior escape abilities and prolonged predator handling time once attacked and captured. Conversely, intermediate-sized Flounder (13 to 17 mm TL) suffered the highest rates of mortality, and this was accentuated with increasing temperature and decreasing Flounder density. Intermediate-sized Flounder (17 mm TL) were the most energetically profitable for shrimp. Below this size, net energy intake of shrimp decreased because of the lower caloric content of smaller Flounder. Above this size, the increased metabolic demands associated with foraging on large Flounder resulted in a decrease in shrimp net-energy gain. Moreover, shrimp feeding on low densities of Flounder suffered a net loss in energy intake, thus possibly explaining the observed density-dependent predation of crangonid species feeding on flatfish. Results from this study chal- lenge the applicability of the bigger-is-better hypothesis to this specific predator-prey interaction.

  • a temperature and size dependent model of sand shrimp crangon septemspinosa predation on juvenile winter Flounder pseudopleuronectes americanus
    Canadian Journal of Fisheries and Aquatic Sciences, 2003
    Co-Authors: David L Taylor, Jeremy S Collie
    Abstract:

    We investigated the temperature-mediated vulnerability of postsettled winter Flounder (Pseudopleuronectes americanus) to sand shrimp (Crangon septemspinosa) predation. Small increases in Flounder growth rates substantially decreased predator-induced mortality. Recent warming trends in Northwest Atlantic estuaries can increase Flounder survival by accelerating growth and minimizing the duration during which juveniles are susceptible to size-dependent predation. Extreme temperature increases, however, depress growth because a disproportionate amount of energy is devoted to increased metabolism, leaving less for somatic development. Flounder survival is also reduced during warm years because of intensified shrimp predation. Moreover, interannual variations in temperature affect the relative timing of shrimp migration and Flounder settlement, thus controlling the spatial and temporal overlap between predator and prey. Predicted Flounder abundance and survival were statistically unrelated to observed Flounder ...

Jeremy S Collie - One of the best experts on this subject based on the ideXlab platform.

  • effect of temperature on the functional response and foraging behavior of the sand shrimp crangon septemspinosa preying on juvenile winter Flounder pseudopleuronectes americanus
    Marine Ecology Progress Series, 2003
    Co-Authors: David L Taylor, Jeremy S Collie
    Abstract:

    Predator-prey dynamics between the sand shrimp Crangon septemspinosa and juvenile winter Flounder Pseudopleuronectes americanus were examined in laboratory experiments to assess the joint effects of varying prey density and temperature on shrimp foraging behavior and Flounder mortality. The functional response of shrimp to 6 densities of Flounder was determined at 2 tempera- tures (10 and 16°C). The behavioral mechanisms underlying the shrimp's functional response were quantified with visual observations and compared to the foraging parameters predicted by continu- ous-time functional response models. Shrimp consumption rates increased significantly with increas- ing Flounder density, irrespective of water temperature. At low Flounder densities, however, signifi- cantly more Flounder were consumed at 16°C than at 10°C. Analysis of proportional mortality of Flounder across prey density and general functional response models revealed a sigmoidal, Type III functional response at 10°C, and a hyperbolic, Type II functional response at 16°C. Model parameter estimates and visual observations of shrimp foraging behavior suggest that the variable functional responses at different temperatures are the result of cold temperatures decreasing predator activity at low Flounder densities, and conversely, shrimp maintaining high attack rates at low Flounder densities when exposed to warm temperatures. These findings indicate that shrimp are capable of driving Flounder populations to local extinction during warm water conditions. The recent warming trend experienced in northwest Atlantic estuaries, and its impact on trophic dynamics, may therefore explain the failure of the winter Flounder stocks to recover in these areas.

  • a temperature and size dependent model of sand shrimp crangon septemspinosa predation on juvenile winter Flounder pseudopleuronectes americanus
    Canadian Journal of Fisheries and Aquatic Sciences, 2003
    Co-Authors: David L Taylor, Jeremy S Collie
    Abstract:

    We investigated the temperature-mediated vulnerability of postsettled winter Flounder (Pseudopleuronectes americanus) to sand shrimp (Crangon septemspinosa) predation. Small increases in Flounder growth rates substantially decreased predator-induced mortality. Recent warming trends in Northwest Atlantic estuaries can increase Flounder survival by accelerating growth and minimizing the duration during which juveniles are susceptible to size-dependent predation. Extreme temperature increases, however, depress growth because a disproportionate amount of energy is devoted to increased metabolism, leaving less for somatic development. Flounder survival is also reduced during warm years because of intensified shrimp predation. Moreover, interannual variations in temperature affect the relative timing of shrimp migration and Flounder settlement, thus controlling the spatial and temporal overlap between predator and prey. Predicted Flounder abundance and survival were statistically unrelated to observed Flounder ...

Takashi Aoki - One of the best experts on this subject based on the ideXlab platform.

  • Molecular cloning and expression study on Toll-like receptor 5 paralogs in Japanese Flounder, Paralichthys olivaceus
    Fish & shellfish immunology, 2010
    Co-Authors: Seong Don Hwang, Takashi Asahi, Hidehiro Kondo, Ikuo Hirono, Takashi Aoki
    Abstract:

    Toll-like receptor (TLR) 5 is responsible for the bacterial flagellin recognition in vertebrates. Synergistic role of TLR 5 membrane form (TLR 5M) and TLR 5 soluble form (TLR 5S) have been reported from the study on rainbow trout. This system is regarded as the unique system in teleost fish. However, systemic response of TLR 5 genes in teleost fish has not been fully understood. Hence, we cloned Japanese Flounder (Paralichthys olivaseus) TLR 5M and TLR 5S genes and their expressions were analyzed. The coding region of Japanese founder TLR 5M and TLR 5S cDNA were 2670 bp and 1923 bp, encoding 889 and 640 amino acid residues, respectively. The Japanese Flounder TLR 5M was composed of an extracellular leucine rich repeats (LRRs), a transmembrane and an intracellular Toll/interleukin-1 receptor (TIR) domains, whereas TLR 5S possessed only the LRR domain. TLR 5M was highly expressed in the gill, head kidney, heart and liver. TLR 5S was highly expressed in the brain, head kidney and heart. Flagellin stimulation (1 and 5 microg/ml) led to strong gene expression of TLR 5S in peripheral blood leukocytes (PBLs) and liver cells. In contrast to TLR 5S, TLR 5M was down-regulated until 3 h after flagellin stimulation in PBLs and liver cells. The flagellin stimulation also resulted in the production of the Flounder IL-1beta and IL-6 from the liver cells and PBLs. The gene expression of TLR 5M was highly induced in the liver, while TLR 5S gene expression was drastically increased in the intestine following challenge with Edwardsiella tarda. Increased number of TLR 5M- and 5S-expressing cell populations were detected by in situ hybridization in the lamina propria of the intestine and liver after E. tarda infection, respectively. These results imply that the expression of these TLR 5 paralogs in Japanese Flounder are differently regulated in the whole body and play important roles in the immune response against bacterial pathogens.

  • molecular cloning characterization and expression of tnf cdna and gene from japanese Flounder paralychthys olivaceus
    Journal of Immunology, 2000
    Co-Authors: Ikuo Hirono, Bohye Nam, Tomofumi Kurobe, Takashi Aoki
    Abstract:

    We cloned a cDNA and the gene for Japanese Flounder TNF. The TNF cDNA consisted of 1217 bp, which encoded 225 amino acid residues. The identities between Japanese Flounder TNF and members of the mammalian TNF family were ∼20–30%. The positions of cysteine residues that are important for disulfide bonds were conserved with respect to those in mammalian TNF-α. The Japanese Flounder TNF gene has a length of ∼2 kbp and consists of four exons and three introns. The positions of the exon-intron junction positions of Japanese Flounder TNF gene are similar to those of human TNF-α. However, the length of the first intron of Japanese Flounder is much shorter than that of the human TNF-α gene. There are simple CA or AT dinucleotide repeats in the 5′-upstream and 3′-downstream regions of the Japanese Flounder TNF gene. Southern blot hybridization indicted that Japanese Flounder TNF exists as a single copy. Expression of Japanese Flounder TNF mRNA is greatly induced after stimulation of PBLs with LPS, Con A, or PMA. These results indicated that Japanese Flounder TNF is more like mammalian TNF-α than mammalian lymphotoxin-α, with respect to its gene structure, length of amino acid sequence, number and position of cysteine residues, and regulation of gene expression.

  • molecular cloning characterization and expression of tnf cdna and gene from japanese Flounder paralychthys olivaceus
    Journal of Immunology, 2000
    Co-Authors: Ikuo Hirono, Bohye Nam, Tomofumi Kurobe, Takashi Aoki
    Abstract:

    We cloned a cDNA and the gene for Japanese Flounder TNF. The TNF cDNA consisted of 1217 bp, which encoded 225 amino acid residues. The identities between Japanese Flounder TNF and members of the mammalian TNF family were approximately 20-30%. The positions of cysteine residues that are important for disulfide bonds were conserved with respect to those in mammalian TNF-alpha. The Japanese Flounder TNF gene has a length of approximately 2 kbp and consists of four exons and three introns. The positions of the exon-intron junction positions of Japanese Flounder TNF gene are similar to those of human TNF-alpha. However, the length of the first intron of Japanese Flounder is much shorter than that of the human TNF-alpha gene. There are simple CA or AT dinucleotide repeats in the 5'-upstream and 3'-downstream regions of the Japanese Flounder TNF gene. Southern blot hybridization indicted that Japanese Flounder TNF exists as a single copy. Expression of Japanese Flounder TNF mRNA is greatly induced after stimulation of PBLs with LPS, Con A, or PMA. These results indicated that Japanese Flounder TNF is more like mammalian TNF-alpha than mammalian lymphotoxin-alpha, with respect to its gene structure, length of amino acid sequence, number and position of cysteine residues, and regulation of gene expression.

Wilhelm H Holzapfel - One of the best experts on this subject based on the ideXlab platform.

  • the effects of combined dietary probiotics lactococcus lactis bfe920 and lactobacillus plantarum fgl0001 on innate immunity and disease resistance in olive Flounder paralichthys olivaceus
    Fish & Shellfish Immunology, 2015
    Co-Authors: Bo Ram Beck, Daniel Kim, Sunmin Lee, Kwanhee Lee, Jongsu Jeon, Hui Kwon Kim, Oijin Kim, Jaeil Lee, Byung Sun Suh, Wilhelm H Holzapfel
    Abstract:

    The effects of a dietary probiotic mixture containing Lactococcus (Lc.) lactis BFE920 isolated from bean sprout and autochthonous Lactobacillus (Lb.) plantarum FGL0001 originally isolated from the hindgut of olive Flounder (Paralichthys olivaceus) were investigated for the purpose of improving the probiotic effects of Lc. lactis BFE920 on the olive Flounder. The immunostimulatory, disease protective, and weight gain effects of Lc. lactis BFE920 were significantly improved when olive Flounder (average weight 37.5±1.26 g) were fed the probiotic mixture (log10 7.0 CFU each/g feed pellet) for 30 days. Flounder fed the mixture showed improved skin mucus lysozyme activity and phagocytic activity of innate immune cells compared to Flounder fed a single probiotic agent or a control diet. While the levels of neutrophil activity in Flounder fed the single probiotic agent or the mixture were similar, they were significantly higher than levels in a control group. Additionally, probiotic-fed Flounder showed significantly increased expressions of IL-6, IL-8, and TNF-α in the intestine compared to the control group. Following a 30-day period of being fed probiotics or a control diet, the olive Flounder were challenged with an i.p. injection of Streptococcus iniae (log10 6.0 CFU/fish). The groups fed the mixed probiotics, Lc. lactis BFE920, Lb. plantarum FGL0001, and the control diet had survival rates of 55%, 45%, 35%, and 20%, respectively. Flounder fed the probiotic mixture gained 38.1±2.8% more body weight compared to Flounder fed the control diet during the 30-day study period. These data strongly suggest that a mixture of Lc. lactis BFE920 and Lb. plantarum FGL0001 may serve as an immunostimulating feed additive useful for disease protection in the fish farming industry.

  • lactococcus lactis bfe920 activates the innate immune system of olive Flounder paralichthys olivaceus resulting in protection against streptococcus iniae infection and enhancing feed efficiency and weight gain in large scale field studies
    Fish & Shellfish Immunology, 2013
    Co-Authors: Daniel Kim, Bo Ram Beck, Saetbyeol Heo, Jungjoon Kim, Hyun Duk Kim, Sunmin Lee, Youngchan Kim, Kyungro Lee, Kwanhee Lee, Wilhelm H Holzapfel
    Abstract:

    The protective effect of a food-grade lactic acid bacterium Lactococcus lactis BFE920 against disease of olive Flounder (Paralichthys olivaceus) cultivated on a large scale was studied. Initially, antimicrobial activity of L. lactis against several fish pathogens was evaluated in vitro; the probiotic showed strong antibacterial activity against Streptococcus iniae, Streptococcus parauberis and Enterococcus viikkiensis, and moderate activity against Lactococcus garviae. When olive Flounders were fed for two weeks with experimental diets containing varying concentrations of L. lactis (1 × 10(6), 5 × 10(6), 2.5 × 10(7) and 1.25 × 10(8) CFU/g feed), all the experimental feed groups showed 68-77% survival upon challenge with S. iniae. A field-scale feeding trial with L. lactis dietary supplement was conducted in a local fish farm (n = 12,000) for three months, and disease resistance, innate immune parameters and growth performance were evaluated. The average weight gain and feed efficiency were increased up to 6.8% and 8.5%, respectively. At the end of the feeding trial, the olive Flounders were challenged with S. iniae. The L. lactis-fed group was protected from S. iniae challenge with a 66% survival rate. This disease protection is due to the Flounder's innate immunity activated by the L. lactis administration: increased lysosomal activities and production of IL-12 and IFN-γ. These data clearly indicated that L. lactis BFE920 may be developed as a functional feed additive for protection against diseases, and for enhancement of feed efficiency and weight gain in olive Flounder farming.

Ikuo Hirono - One of the best experts on this subject based on the ideXlab platform.

  • Molecular cloning and expression study on Toll-like receptor 5 paralogs in Japanese Flounder, Paralichthys olivaceus
    Fish & shellfish immunology, 2010
    Co-Authors: Seong Don Hwang, Takashi Asahi, Hidehiro Kondo, Ikuo Hirono, Takashi Aoki
    Abstract:

    Toll-like receptor (TLR) 5 is responsible for the bacterial flagellin recognition in vertebrates. Synergistic role of TLR 5 membrane form (TLR 5M) and TLR 5 soluble form (TLR 5S) have been reported from the study on rainbow trout. This system is regarded as the unique system in teleost fish. However, systemic response of TLR 5 genes in teleost fish has not been fully understood. Hence, we cloned Japanese Flounder (Paralichthys olivaseus) TLR 5M and TLR 5S genes and their expressions were analyzed. The coding region of Japanese founder TLR 5M and TLR 5S cDNA were 2670 bp and 1923 bp, encoding 889 and 640 amino acid residues, respectively. The Japanese Flounder TLR 5M was composed of an extracellular leucine rich repeats (LRRs), a transmembrane and an intracellular Toll/interleukin-1 receptor (TIR) domains, whereas TLR 5S possessed only the LRR domain. TLR 5M was highly expressed in the gill, head kidney, heart and liver. TLR 5S was highly expressed in the brain, head kidney and heart. Flagellin stimulation (1 and 5 microg/ml) led to strong gene expression of TLR 5S in peripheral blood leukocytes (PBLs) and liver cells. In contrast to TLR 5S, TLR 5M was down-regulated until 3 h after flagellin stimulation in PBLs and liver cells. The flagellin stimulation also resulted in the production of the Flounder IL-1beta and IL-6 from the liver cells and PBLs. The gene expression of TLR 5M was highly induced in the liver, while TLR 5S gene expression was drastically increased in the intestine following challenge with Edwardsiella tarda. Increased number of TLR 5M- and 5S-expressing cell populations were detected by in situ hybridization in the lamina propria of the intestine and liver after E. tarda infection, respectively. These results imply that the expression of these TLR 5 paralogs in Japanese Flounder are differently regulated in the whole body and play important roles in the immune response against bacterial pathogens.

  • molecular cloning characterization and expression of tnf cdna and gene from japanese Flounder paralychthys olivaceus
    Journal of Immunology, 2000
    Co-Authors: Ikuo Hirono, Bohye Nam, Tomofumi Kurobe, Takashi Aoki
    Abstract:

    We cloned a cDNA and the gene for Japanese Flounder TNF. The TNF cDNA consisted of 1217 bp, which encoded 225 amino acid residues. The identities between Japanese Flounder TNF and members of the mammalian TNF family were ∼20–30%. The positions of cysteine residues that are important for disulfide bonds were conserved with respect to those in mammalian TNF-α. The Japanese Flounder TNF gene has a length of ∼2 kbp and consists of four exons and three introns. The positions of the exon-intron junction positions of Japanese Flounder TNF gene are similar to those of human TNF-α. However, the length of the first intron of Japanese Flounder is much shorter than that of the human TNF-α gene. There are simple CA or AT dinucleotide repeats in the 5′-upstream and 3′-downstream regions of the Japanese Flounder TNF gene. Southern blot hybridization indicted that Japanese Flounder TNF exists as a single copy. Expression of Japanese Flounder TNF mRNA is greatly induced after stimulation of PBLs with LPS, Con A, or PMA. These results indicated that Japanese Flounder TNF is more like mammalian TNF-α than mammalian lymphotoxin-α, with respect to its gene structure, length of amino acid sequence, number and position of cysteine residues, and regulation of gene expression.

  • molecular cloning characterization and expression of tnf cdna and gene from japanese Flounder paralychthys olivaceus
    Journal of Immunology, 2000
    Co-Authors: Ikuo Hirono, Bohye Nam, Tomofumi Kurobe, Takashi Aoki
    Abstract:

    We cloned a cDNA and the gene for Japanese Flounder TNF. The TNF cDNA consisted of 1217 bp, which encoded 225 amino acid residues. The identities between Japanese Flounder TNF and members of the mammalian TNF family were approximately 20-30%. The positions of cysteine residues that are important for disulfide bonds were conserved with respect to those in mammalian TNF-alpha. The Japanese Flounder TNF gene has a length of approximately 2 kbp and consists of four exons and three introns. The positions of the exon-intron junction positions of Japanese Flounder TNF gene are similar to those of human TNF-alpha. However, the length of the first intron of Japanese Flounder is much shorter than that of the human TNF-alpha gene. There are simple CA or AT dinucleotide repeats in the 5'-upstream and 3'-downstream regions of the Japanese Flounder TNF gene. Southern blot hybridization indicted that Japanese Flounder TNF exists as a single copy. Expression of Japanese Flounder TNF mRNA is greatly induced after stimulation of PBLs with LPS, Con A, or PMA. These results indicated that Japanese Flounder TNF is more like mammalian TNF-alpha than mammalian lymphotoxin-alpha, with respect to its gene structure, length of amino acid sequence, number and position of cysteine residues, and regulation of gene expression.