The Experts below are selected from a list of 36 Experts worldwide ranked by ideXlab platform

David W. Weisrock - One of the best experts on this subject based on the ideXlab platform.

  • A genomic assessment of population structure and gene flow in an aquatic salamander identifies the roles of spatial scale, barriers, and river architecture
    Freshwater Biology, 2018
    Co-Authors: Mason O. Murphy, Kara S. Jones, Steven J. Price, David W. Weisrock
    Abstract:

    Population structure and gene flow of species in lotic environments can be constrained by river network architecture, species life history and heterogeneous local barriers. Identifying the factors that influence population structure and gene flow, especially in species limited to movement within a river network, is vital for understanding the evolutionary and demographic history of a species. We explored population structure and gene flow for a fully aquatic salamander, the Common Mudpuppy (Necturus maculosus), in Kentucky (USA) using genomic data. We examined population structure using both parametric and nonparametric methods, and we tested for a history of lineage divergence among identified genetic clusters. We quantified the partitioning of genetic variation at different hierarchical levels, and we tested for signatures of isolation by distance. Additionally, we used coalescent‐based model selection to identify a best‐fit model of gene flow between our three sampled basins. We found the greatest support for population structure between the Kentucky River basin and the combined Licking and Kinniconick basins, with further subdivision within both the Kentucky and Licking River basins. However, we found no evidence for a history of lineage divergence among these structured units. The movement of N. maculosus is constrained by the lotic network architecture, which likely drives the evolution of this hierarchical population structure, with increasing differentiation between sites nested in river basins, and even greater differentiation between basins. However, we also found evidence for population structure not explained by river architecture, with an isolated population embedded within the Kentucky River basin. This study demonstrates the heterogeneity in population structure that can evolve in aquatic species occupying lotic systems and illustrates the potential for genomic data to disentangle these complex patterns.

Boris Bulog - One of the best experts on this subject based on the ideXlab platform.

  • isolation and primary culture of necturus maculosus amphibia urodela hepatocytes
    In Vitro Cellular & Developmental Biology – Animal, 2006
    Co-Authors: Petramaja Prelovsek, Urska Batista, Boris Bulog
    Abstract:

    In order to evaluate their suitability for physiological and ecotoxicological studies, hepatocytes were isolated from the Common Mudpuppy (Necturus maculosus) using a two-step collagenase perfusion. Hepatocytes in primary culture were investigated for 14 d using light and electron microscopy and biochemical analyses. A typical perfusion yielded 1.7×105 viable hepatocytes per gram body weight with an average viability of 86±5%. The majority of isolated cells remained in suspension and formed aggregates. The viability of hepatocytes in primary culture was dependent on a fetal calf serum (FCS) concentration and incubation temperature. Viability was best at 8°C in Leibovitz L-15 medium supplemented with 5% FCS. The ultrastructural characteristics of freshly isolated hepatocytes resembled those of N. maculosus hepatocytes in vivo. Whereas hepatocyte viability remained relatively stable (around 80%) up to 14 d in culture, electron microscopic analyses revealed changes at ultrastructural level. The majority of hepatocytes retained similar structural characteristics to those in vivo up to 4 d. Loss of cellular polarity, fractionation of rough endoplasmic reticulum, formation of autophagosomes, and successive exhaustion of cellular glycogen deposits were observed with increased time in culture. Functional integrity, as estimated by tyrosine aminotransferase induction, decreased during the culture period. Ultrastructural and biochemical analyses indicate the need for further improvement of culture conditions. Nevertheless, isolated hepatocytes in primary culture for up to 4 d can be recommended as a model for physiological and toxicological studies in lower vertebrates.

  • Isolation and primary culture of Necturus maculosus (Amphibia: Urodela) hepatocytes.
    In Vitro Cellular & Developmental Biology - Animal, 2006
    Co-Authors: Petramaja Prelovsek, Urska Batista, Boris Bulog
    Abstract:

    Abstract In order to evaluate their suitability for physiological and ecotoxicological studies, hepatocytes were isolated from the Common Mudpuppy (Necturus maculosus) using a two-step collagenase perfusion. Hepatocytes in primary culture were investigated for 14 d using light and electron microscopy and biochemical analyses. A typical perfusion yielded 1.7 × 105 viable hepatocytes per gram body weight with an average viability of 86 ± 5%. The majority of isolated cells remained in suspension and formed aggregates. The viability of hepatocytes in primary culture was dependent on a fetal calf serum (FCS) concentration and incubation temperature. Viability was best at 8° C in Leibovitz L-15 medium supplemented with 5% FCS. The ultrastructural characteristics of freshly isolated hepatocytes resembled those of N. maculosus hepatocytes in vivo. Whereas hepatocyte viability remained relatively stable (around 80%) up to 14 d in culture, electron microscopic analyses revealed changes at ultrastructural level. The...

  • Isolation and primary culture of Necturus maculosus (Amphibia: Urodela) hepatocytes.
    In vitro cellular & developmental biology. Animal, 2006
    Co-Authors: Petramaja Prelovsek, Urska Batista, Boris Bulog
    Abstract:

    In order to evaluate their suitability for physiological and ecotoxicological studies, hepatocytes were isolated from the Common Mudpuppy (Necturus maculosus) using a two-step collagenase perfusion. Hepatocytes in primary culture were investigated for 14 d using light and electron microscopy and biochemical analyses. A typical perfusion yielded 1.7 x 10(5) viable hepatocytes per gram body weight with an average viability of 86 +/- 5%. The majority of isolated cells remained in suspension and formed aggregates. The viability of hepatocytes in primary culture was dependent on a fetal calf serum (FCS) concentration and incubation temperature. Viability was best at 8 degrees C in Leibovitz L-15 medium supplemented with 5% FCS. The ultrastructural characteristics of freshly isolated hepatocytes resembled those of N. maculosus hepatocytes in vivo. Whereas hepatocyte viability remained relatively stable (around 80%) up to 14 d in culture, electron microscopic analyses revealed changes at ultrastructural level. The majority of hepatocytes retained similar structural characteristics to those in vivo up to 4 d. Loss of cellular polarity, fractionation of rough endoplasmic reticulum, formation of autophagosomes, and successive exhaustion of cellular glycogen deposits were observed with increased time in culture. Functional integrity, as estimated by tyrosine aminotransferase induction, decreased during the culture period. Ultrastructural and biochemical analyses indicate the need for further improvement of culture conditions. Nevertheless, isolated hepatocytes in primary culture for up to 4 d can be recommended as a model for physiological and toxicological studies in lower vertebrates.

Mason O. Murphy - One of the best experts on this subject based on the ideXlab platform.

  • A genomic assessment of population structure and gene flow in an aquatic salamander identifies the roles of spatial scale, barriers, and river architecture
    Freshwater Biology, 2018
    Co-Authors: Mason O. Murphy, Kara S. Jones, Steven J. Price, David W. Weisrock
    Abstract:

    Population structure and gene flow of species in lotic environments can be constrained by river network architecture, species life history and heterogeneous local barriers. Identifying the factors that influence population structure and gene flow, especially in species limited to movement within a river network, is vital for understanding the evolutionary and demographic history of a species. We explored population structure and gene flow for a fully aquatic salamander, the Common Mudpuppy (Necturus maculosus), in Kentucky (USA) using genomic data. We examined population structure using both parametric and nonparametric methods, and we tested for a history of lineage divergence among identified genetic clusters. We quantified the partitioning of genetic variation at different hierarchical levels, and we tested for signatures of isolation by distance. Additionally, we used coalescent‐based model selection to identify a best‐fit model of gene flow between our three sampled basins. We found the greatest support for population structure between the Kentucky River basin and the combined Licking and Kinniconick basins, with further subdivision within both the Kentucky and Licking River basins. However, we found no evidence for a history of lineage divergence among these structured units. The movement of N. maculosus is constrained by the lotic network architecture, which likely drives the evolution of this hierarchical population structure, with increasing differentiation between sites nested in river basins, and even greater differentiation between basins. However, we also found evidence for population structure not explained by river architecture, with an isolated population embedded within the Kentucky River basin. This study demonstrates the heterogeneity in population structure that can evolve in aquatic species occupying lotic systems and illustrates the potential for genomic data to disentangle these complex patterns.

Petramaja Prelovsek - One of the best experts on this subject based on the ideXlab platform.

  • isolation and primary culture of necturus maculosus amphibia urodela hepatocytes
    In Vitro Cellular & Developmental Biology – Animal, 2006
    Co-Authors: Petramaja Prelovsek, Urska Batista, Boris Bulog
    Abstract:

    In order to evaluate their suitability for physiological and ecotoxicological studies, hepatocytes were isolated from the Common Mudpuppy (Necturus maculosus) using a two-step collagenase perfusion. Hepatocytes in primary culture were investigated for 14 d using light and electron microscopy and biochemical analyses. A typical perfusion yielded 1.7×105 viable hepatocytes per gram body weight with an average viability of 86±5%. The majority of isolated cells remained in suspension and formed aggregates. The viability of hepatocytes in primary culture was dependent on a fetal calf serum (FCS) concentration and incubation temperature. Viability was best at 8°C in Leibovitz L-15 medium supplemented with 5% FCS. The ultrastructural characteristics of freshly isolated hepatocytes resembled those of N. maculosus hepatocytes in vivo. Whereas hepatocyte viability remained relatively stable (around 80%) up to 14 d in culture, electron microscopic analyses revealed changes at ultrastructural level. The majority of hepatocytes retained similar structural characteristics to those in vivo up to 4 d. Loss of cellular polarity, fractionation of rough endoplasmic reticulum, formation of autophagosomes, and successive exhaustion of cellular glycogen deposits were observed with increased time in culture. Functional integrity, as estimated by tyrosine aminotransferase induction, decreased during the culture period. Ultrastructural and biochemical analyses indicate the need for further improvement of culture conditions. Nevertheless, isolated hepatocytes in primary culture for up to 4 d can be recommended as a model for physiological and toxicological studies in lower vertebrates.

  • Isolation and primary culture of Necturus maculosus (Amphibia: Urodela) hepatocytes.
    In Vitro Cellular & Developmental Biology - Animal, 2006
    Co-Authors: Petramaja Prelovsek, Urska Batista, Boris Bulog
    Abstract:

    Abstract In order to evaluate their suitability for physiological and ecotoxicological studies, hepatocytes were isolated from the Common Mudpuppy (Necturus maculosus) using a two-step collagenase perfusion. Hepatocytes in primary culture were investigated for 14 d using light and electron microscopy and biochemical analyses. A typical perfusion yielded 1.7 × 105 viable hepatocytes per gram body weight with an average viability of 86 ± 5%. The majority of isolated cells remained in suspension and formed aggregates. The viability of hepatocytes in primary culture was dependent on a fetal calf serum (FCS) concentration and incubation temperature. Viability was best at 8° C in Leibovitz L-15 medium supplemented with 5% FCS. The ultrastructural characteristics of freshly isolated hepatocytes resembled those of N. maculosus hepatocytes in vivo. Whereas hepatocyte viability remained relatively stable (around 80%) up to 14 d in culture, electron microscopic analyses revealed changes at ultrastructural level. The...

  • Isolation and primary culture of Necturus maculosus (Amphibia: Urodela) hepatocytes.
    In vitro cellular & developmental biology. Animal, 2006
    Co-Authors: Petramaja Prelovsek, Urska Batista, Boris Bulog
    Abstract:

    In order to evaluate their suitability for physiological and ecotoxicological studies, hepatocytes were isolated from the Common Mudpuppy (Necturus maculosus) using a two-step collagenase perfusion. Hepatocytes in primary culture were investigated for 14 d using light and electron microscopy and biochemical analyses. A typical perfusion yielded 1.7 x 10(5) viable hepatocytes per gram body weight with an average viability of 86 +/- 5%. The majority of isolated cells remained in suspension and formed aggregates. The viability of hepatocytes in primary culture was dependent on a fetal calf serum (FCS) concentration and incubation temperature. Viability was best at 8 degrees C in Leibovitz L-15 medium supplemented with 5% FCS. The ultrastructural characteristics of freshly isolated hepatocytes resembled those of N. maculosus hepatocytes in vivo. Whereas hepatocyte viability remained relatively stable (around 80%) up to 14 d in culture, electron microscopic analyses revealed changes at ultrastructural level. The majority of hepatocytes retained similar structural characteristics to those in vivo up to 4 d. Loss of cellular polarity, fractionation of rough endoplasmic reticulum, formation of autophagosomes, and successive exhaustion of cellular glycogen deposits were observed with increased time in culture. Functional integrity, as estimated by tyrosine aminotransferase induction, decreased during the culture period. Ultrastructural and biochemical analyses indicate the need for further improvement of culture conditions. Nevertheless, isolated hepatocytes in primary culture for up to 4 d can be recommended as a model for physiological and toxicological studies in lower vertebrates.

Steven J. Price - One of the best experts on this subject based on the ideXlab platform.

  • A genomic assessment of population structure and gene flow in an aquatic salamander identifies the roles of spatial scale, barriers, and river architecture
    Freshwater Biology, 2018
    Co-Authors: Mason O. Murphy, Kara S. Jones, Steven J. Price, David W. Weisrock
    Abstract:

    Population structure and gene flow of species in lotic environments can be constrained by river network architecture, species life history and heterogeneous local barriers. Identifying the factors that influence population structure and gene flow, especially in species limited to movement within a river network, is vital for understanding the evolutionary and demographic history of a species. We explored population structure and gene flow for a fully aquatic salamander, the Common Mudpuppy (Necturus maculosus), in Kentucky (USA) using genomic data. We examined population structure using both parametric and nonparametric methods, and we tested for a history of lineage divergence among identified genetic clusters. We quantified the partitioning of genetic variation at different hierarchical levels, and we tested for signatures of isolation by distance. Additionally, we used coalescent‐based model selection to identify a best‐fit model of gene flow between our three sampled basins. We found the greatest support for population structure between the Kentucky River basin and the combined Licking and Kinniconick basins, with further subdivision within both the Kentucky and Licking River basins. However, we found no evidence for a history of lineage divergence among these structured units. The movement of N. maculosus is constrained by the lotic network architecture, which likely drives the evolution of this hierarchical population structure, with increasing differentiation between sites nested in river basins, and even greater differentiation between basins. However, we also found evidence for population structure not explained by river architecture, with an isolated population embedded within the Kentucky River basin. This study demonstrates the heterogeneity in population structure that can evolve in aquatic species occupying lotic systems and illustrates the potential for genomic data to disentangle these complex patterns.