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D. Siebers - One of the best experts on this subject based on the ideXlab platform.
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Gelation kinetics of the gel collected from the corneocytes of the Pilot Whale, Globicephala melas
2020Co-Authors: Christof Baum, L. G. Fleischer, D. Siebers, W Meyer, Ralph StelzerAbstract:Summary. We have reported on the smooth and clean skin surface of the Pilot Whale Globicephala melas (Baum et al 2000 Aquatic Mammals 26:7). Smoothness and self-cleaning abilities of the skin surface are based on a gel that filles the nanoscalic inter-cellular space between the corneocytes. This gel is an important factor in the defence against adhesive glycoconjugates and organisms, that may negatively influence health and hydrodynamic demands of the dolphin. It was our aim to measure the rheological properties of the gel in order to confirm its viscoelastic behaviour predicted from our previous findings.Untreated fresh frozen skin samples of the Pilot Whale and centrifugates of mechani-cally ablated corneocytes were prepared for cryo-scanning electron microscopy (see Baum et al 2000 Aquatic Mammals 26:7). We examined the surface sculptures of the samples and documented different grades of polymerization seen in the centrifugates. Changes in viscoelasticity of the centrifugates were immediately after centrifugation monitored by means of a stress-controlled rheometer (Haake RS 150) with cone-and-plate geometry (35 mm, apex angle 1°) under oszillatory shear conditions.When centrifugates polymerized, their surface morphology appeared similar to the sur-faces of the untreated fresh skin samples. The gelation kinetics measured confirm that the centrifugates underwent polymerization within 2.5 - 3 hours after processing. At the beginning of the experiments, the high fluctuating pattern of the storage modul GŽ showed the presence of performed aggregates, which were destroyed by the oszillating force. After 2.5 - 3 hours new aggregates built up a gel. We found that in vitro the gela-tion terminates in a duroplastic gel, indicating gelation based on covently cross-linked network bridges.We thank Dr. D. Bloch and Dr. H.-P. Joensen, University of the Faroe Islands, for their help in specimen collection from legal harvest. This study was supported by a grant of the Deutsche Forschungsgemeinschaft (ME 1755/ 1-1).
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surface properties of the skin of the Pilot Whale globicephala melas
Biofouling, 2003Co-Authors: Christof Baum, D. Siebers, Wilfried Meyer, Frank Simon, Lutzgunther Fleischer, Johannes Kacza, Johannes SeegerAbstract:On the skin surface of delphinids small biofoulers are challenged to high shear water flow and liquid-vapor interfaces of air-bubbles during jumping. This state of self-cleaning is supported by the even, nano-rough gel-coated epidermal surface of the skin. The present study focussed on the intercellular evolution of gel formation and the chemical composition of the gel smoothing the skin surface of the Pilot Whale, Globicephala melas , using X-ray photoelectron spectroscopy (XPS) in combination with cryo-scanning electron microscopy (CSM), and transmission electron microscopy (TEM). In the superficial layer of the epidermis, the stratum corneum, intercellular material was shown by electron optical methods to assemble from smaller into larger covalently cross-linked aggregates during the transit of the corneocytes towards the skin surface. XPS measurements showed that the surface of the skin and the intercellular gel included approximately the same amounts of polar groups (especially, free amines and amide...
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Average nanorough skin surface of the Pilot Whale (Globicephala melas, Delphinidae): Considerations on the self-cleaning abilities based on nanoroughness
Marine Biology, 2002Co-Authors: C Baum, L. G. Fleischer, Ralph Stelzer, Wilfried Meyer, D. SiebersAbstract:In aquatic environments, the biofouling process is assumed to initiate from the conditioning layer of absorbed organic carbon residues on wetted surfaces. Microfouling organisms attach to this conditioning layer, building up a biofilm on which further biofouling proceeds. In dolphins, biofouling reduces hydrodynamic efficiency and may negatively affect health if not managed. In the present study we examined the skin surface of the Pilot Whale (Globicephala melas). Employing cryo-scanning electron microscopic techniques combined with various sample preparations, the skin displayed an average nanorough surface characterized by a pattern of nanoridge-enclosed pores; the average pore size (approximately 0.20 µm2) was below the size of most marine biofouling organisms. Further, the implications of this type of surface to the self-cleaning abilities of the skin of Pilot Whales are discussed, based on reduced available space for biofouler attachment, the lack of any particular microniches as shelters for biofoulers, and the challenges of turbulent water flow and liquid–air interfaces during surfacing and jumping of the dolphin.
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a covalently cross linked gel derived from the epidermis of the Pilot Whale globicephala melas
Biorheology, 2002Co-Authors: Christof Baum, L. G. Fleischer, W Meyer, D Roessner, D. SiebersAbstract:: The rheological properties of the stratum corneum of the Pilot Whale (Globicephala melas) were investigated with emphasis on their significance to the self-cleaning abilities of the skin surface smoothed by a jelly material enriched with various hydrolytic enzymes. The gel formation of the collected fluid was monitored by applying periodic-harmonic oscillating loads using a stress-controlled rheometer. In the mechanical spectrum of the gel, the plateau region of the storage modulus G' ( 120 Pa) were independent of frequency (omega = 43.98 to 0.13 rad x s(-1), tau = 15 Pa, T = 20 degrees C), indicating high elastic performance of a covalently cross-linked viscoelastic solid. In addition, multi-angle laser light scattering experiments (MALLS) were performed to analyse the potential time-dependent changes in the weight-average molar mass of the samples. The observed increase showed that the gel formation is based on the assembly of covalently cross-linked aggregates. The viscoelastic properties and the shear resistance of the gel assure that the enzyme-containing jelly material smoothing the skin surface is not removed from the stratum corneum by shear regimes during dolphin jumping. The even skin surface is considered to be most important for the self-cleaning abilities of the dolphin skin against biofouling.
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a zymogel enhances the self cleaning abilities of the skin of the Pilot Whale globicephala melas
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2001Co-Authors: Christof Baum, Wilfried Meyer, D. Siebers, D Roessner, L. G. FleischerAbstract:Enzyme activity in the stratum corneum of the Pilot Whale Globicephala melas was investigated employing colorimetric enzyme screening assays combined with NATIVE PAGE, size exclusion chromatography (SEC) and histochemical staining procedures. Applying different substrates, several enzymes were detected. The histochemical demonstration of some selected hydrolytic enzymes enriched in the stratum corneum showed high extracellular accumulation. As demonstrated by size exclusion chromatography, high molar mass aggregates were built up from a glycoprotein-rich 20–30-kD fraction. Using NATIVE PAGE experiments under non-reducing conditions, a selection of five degrading enzymes was recovered within the above-reported aggregates. Activity of extracellular aggregate-attached enzymes in the superficial layer of the stratum corneum exhibited no remarkable decrease potentially resulting from self-degradation. We thus conclude that due to their enclosure within the microenvironment of aggregates, a zymogel is formed and autolysis of the stratum corneum is reduced. With respect to the skin surface, the zymogel with hydrolytic activities covering major parts of it enhances the self-cleaning abilities of the skin of the Pilot Whale based on physical pre-requisites by hydrolyzing adhesive glycoconjugates of settling biofouling organisms considered as primary steps in fouling.
Christof Baum - One of the best experts on this subject based on the ideXlab platform.
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Gelation kinetics of the gel collected from the corneocytes of the Pilot Whale, Globicephala melas
2020Co-Authors: Christof Baum, L. G. Fleischer, D. Siebers, W Meyer, Ralph StelzerAbstract:Summary. We have reported on the smooth and clean skin surface of the Pilot Whale Globicephala melas (Baum et al 2000 Aquatic Mammals 26:7). Smoothness and self-cleaning abilities of the skin surface are based on a gel that filles the nanoscalic inter-cellular space between the corneocytes. This gel is an important factor in the defence against adhesive glycoconjugates and organisms, that may negatively influence health and hydrodynamic demands of the dolphin. It was our aim to measure the rheological properties of the gel in order to confirm its viscoelastic behaviour predicted from our previous findings.Untreated fresh frozen skin samples of the Pilot Whale and centrifugates of mechani-cally ablated corneocytes were prepared for cryo-scanning electron microscopy (see Baum et al 2000 Aquatic Mammals 26:7). We examined the surface sculptures of the samples and documented different grades of polymerization seen in the centrifugates. Changes in viscoelasticity of the centrifugates were immediately after centrifugation monitored by means of a stress-controlled rheometer (Haake RS 150) with cone-and-plate geometry (35 mm, apex angle 1°) under oszillatory shear conditions.When centrifugates polymerized, their surface morphology appeared similar to the sur-faces of the untreated fresh skin samples. The gelation kinetics measured confirm that the centrifugates underwent polymerization within 2.5 - 3 hours after processing. At the beginning of the experiments, the high fluctuating pattern of the storage modul GŽ showed the presence of performed aggregates, which were destroyed by the oszillating force. After 2.5 - 3 hours new aggregates built up a gel. We found that in vitro the gela-tion terminates in a duroplastic gel, indicating gelation based on covently cross-linked network bridges.We thank Dr. D. Bloch and Dr. H.-P. Joensen, University of the Faroe Islands, for their help in specimen collection from legal harvest. This study was supported by a grant of the Deutsche Forschungsgemeinschaft (ME 1755/ 1-1).
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surface properties of the skin of the Pilot Whale globicephala melas
Biofouling, 2003Co-Authors: Christof Baum, D. Siebers, Wilfried Meyer, Frank Simon, Lutzgunther Fleischer, Johannes Kacza, Johannes SeegerAbstract:On the skin surface of delphinids small biofoulers are challenged to high shear water flow and liquid-vapor interfaces of air-bubbles during jumping. This state of self-cleaning is supported by the even, nano-rough gel-coated epidermal surface of the skin. The present study focussed on the intercellular evolution of gel formation and the chemical composition of the gel smoothing the skin surface of the Pilot Whale, Globicephala melas , using X-ray photoelectron spectroscopy (XPS) in combination with cryo-scanning electron microscopy (CSM), and transmission electron microscopy (TEM). In the superficial layer of the epidermis, the stratum corneum, intercellular material was shown by electron optical methods to assemble from smaller into larger covalently cross-linked aggregates during the transit of the corneocytes towards the skin surface. XPS measurements showed that the surface of the skin and the intercellular gel included approximately the same amounts of polar groups (especially, free amines and amide...
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a covalently cross linked gel derived from the epidermis of the Pilot Whale globicephala melas
Biorheology, 2002Co-Authors: Christof Baum, L. G. Fleischer, W Meyer, D Roessner, D. SiebersAbstract:: The rheological properties of the stratum corneum of the Pilot Whale (Globicephala melas) were investigated with emphasis on their significance to the self-cleaning abilities of the skin surface smoothed by a jelly material enriched with various hydrolytic enzymes. The gel formation of the collected fluid was monitored by applying periodic-harmonic oscillating loads using a stress-controlled rheometer. In the mechanical spectrum of the gel, the plateau region of the storage modulus G' ( 120 Pa) were independent of frequency (omega = 43.98 to 0.13 rad x s(-1), tau = 15 Pa, T = 20 degrees C), indicating high elastic performance of a covalently cross-linked viscoelastic solid. In addition, multi-angle laser light scattering experiments (MALLS) were performed to analyse the potential time-dependent changes in the weight-average molar mass of the samples. The observed increase showed that the gel formation is based on the assembly of covalently cross-linked aggregates. The viscoelastic properties and the shear resistance of the gel assure that the enzyme-containing jelly material smoothing the skin surface is not removed from the stratum corneum by shear regimes during dolphin jumping. The even skin surface is considered to be most important for the self-cleaning abilities of the dolphin skin against biofouling.
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a zymogel enhances the self cleaning abilities of the skin of the Pilot Whale globicephala melas
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2001Co-Authors: Christof Baum, Wilfried Meyer, D. Siebers, D Roessner, L. G. FleischerAbstract:Enzyme activity in the stratum corneum of the Pilot Whale Globicephala melas was investigated employing colorimetric enzyme screening assays combined with NATIVE PAGE, size exclusion chromatography (SEC) and histochemical staining procedures. Applying different substrates, several enzymes were detected. The histochemical demonstration of some selected hydrolytic enzymes enriched in the stratum corneum showed high extracellular accumulation. As demonstrated by size exclusion chromatography, high molar mass aggregates were built up from a glycoprotein-rich 20–30-kD fraction. Using NATIVE PAGE experiments under non-reducing conditions, a selection of five degrading enzymes was recovered within the above-reported aggregates. Activity of extracellular aggregate-attached enzymes in the superficial layer of the stratum corneum exhibited no remarkable decrease potentially resulting from self-degradation. We thus conclude that due to their enclosure within the microenvironment of aggregates, a zymogel is formed and autolysis of the stratum corneum is reduced. With respect to the skin surface, the zymogel with hydrolytic activities covering major parts of it enhances the self-cleaning abilities of the skin of the Pilot Whale based on physical pre-requisites by hydrolyzing adhesive glycoconjugates of settling biofouling organisms considered as primary steps in fouling.
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a zymogel enhances the self cleaning abilities of the Pilot Whale globicephala melas
EPIC3Comparative biochemistry and physiology a-molecular and integrative physiology 130 pp. 835-847, 2001Co-Authors: Christof Baum, L. G. Fleischer, Ralph Stelzer, W Meyer, D. SiebersAbstract:Summary. Enzyme activity in the stratum corneum of the Pilot Whale Globicephala melas was investigated employing colorimetric enzyme screening assays combined with NATIVE PAGE, size exclusion chromatography (SEC) and histochemical staining procedures. Applying different substrates, several enzymes were detected. The histochemical demonstration of some selected hydrolytic enzymes enriched in the stratum corneum showed high extracellular accumulation. As demonstrated by size exclusion chromatography, high molar mass aggregates were built up from a glycoprotein-rich 20-30 kD fraction. Using NATIVE PAGE experiments under non reducing conditions, a selection of five degrading enzymes was recovered within the above-reported aggregates.Activity of extracellular aggregate-attached enzymes in the superficial layer of the stratum corneum exhibited no remarkable decrease potentially resulting from self-degradation. We thus conclude that due to their enclosure within the micro-environment of aggregates a zymogel is formed and autolysis of the stratum corneum is reduced. With respect to the skin surface, the zymogel with hydrolytic activities covering major parts of it enhances the self-cleaning abilities of the skin of the Pilot Whale based on physical prequesites by hydrolysing adhesive glycoconjugates of settling biofouling organisms considered as primary steps in fouling.
Peter J Morgane - One of the best experts on this subject based on the ideXlab platform.
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distribution of dopaminergic fibers and neurons in visual and auditory cortices of the harbor porpoise and Pilot Whale
Brain Research Bulletin, 1995Co-Authors: Ilya I Glezer, A V Revishchin, Constantin Bouras, Yves Charnay, Peter J MorganeAbstract:Abstract The distribution of putative dopaminergic fibers in two sensory cortical areas in the brain of the harbor porpoise ( Phocoena pbocoena ) and Pilot Whale ( Globlcephala melaena ) was analyzed at the light and electron microscopic levels using tyrosine hydroxylase (TH) immunohistochemistry. The quantitative analysis of the distribution of labeled fibers demonstrates that the primary visual cortex located in the lateral gyrus and entolateral sulcus contains a denser dopaminergic innervation than the auditory cortex within the posterior portion of the presylvian gyrus. In both areas, TH-immunoreactivefibem are densest in layer I, while layers Illab and VI have intermediate densities and layers II and IIIc-V have the lowest fiber counts. Layer I is characterized by the presence of very thick TH-immunoreactive fiber populations, in addition to the thin and varicose fiber plexus observed throughout the cortical layers. Electron microscopic analyses demonstrated that some of these thick fibers represent the dendrites of TH-immunoreactive neurons located in the deep portion of layer I. The pattems observed in the present study suggest that the dopaminergic projections to the neocortex in Whales have a different organization than in terrestrial mammals, particularly rodents and primates. These differences may reflect the fact that during evolution, the cetacean neocortex has retained many of the cytoarchitectonic features that are usually observed only in proisocortical regions in progressive terrestrial mammals.
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ultrastructure of synapses and golgi analysis of neurons in neocortex of the lateral gyrus visual cortex of the dolphin and Pilot Whale
Brain Research Bulletin, 1990Co-Authors: Ilya I Glezer, Peter J MorganeAbstract:Abstract Qualitative and computerized quantitative analyses of ultrastructural features of synapses in different layers of the primary visual cortex in the dolphin ( Stenella coeruleoalba ) and the Pilot Whale ( Globicephala melaena ) were carried out. Also, Golgi and cytoarchitectonic analyses were performed in the same species of cetaceans and, additionally, in Tursiops truncatus and Phocaena phocaena . It was found that on a synaptic level, as well as in cytoarchitectonic and Golgi features, the neocortex of cetaceans combines evolutionary progressive features and conservative features with a marked prevalence of the latter. Thus, the total number of synapses in visual neocortex in cetaceans is closer to this value in higher Primates. On the other hand, the laminar density of synapses per mm 3 is generally the same in all layers in cetacean visual cortex and numerically is close to values found in small lissencephalic brains. Also, the synapse/neuron ratio in the dolphin visual cortex is of the same order as in cortices of rodents and lagomorphs and much higher than in cortices of advanced terrestrial mammals. Layers I and II contain approximately 70% of the total synapses in the cortical slab through visual cortex. Layer I also contains the extraverted dendrites of neurons of layer II and thus these two layers resemble a paleoarchicortical type of organization superimposed on a more typical neocortical organization of the lower cortical layers. In this respect the convexity neocortex of cetaceans is generally similar to the neocortices of phylogenetically ancient extant mammals such as basal Insectivora and Chiroptera.
L. G. Fleischer - One of the best experts on this subject based on the ideXlab platform.
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Gelation kinetics of the gel collected from the corneocytes of the Pilot Whale, Globicephala melas
2020Co-Authors: Christof Baum, L. G. Fleischer, D. Siebers, W Meyer, Ralph StelzerAbstract:Summary. We have reported on the smooth and clean skin surface of the Pilot Whale Globicephala melas (Baum et al 2000 Aquatic Mammals 26:7). Smoothness and self-cleaning abilities of the skin surface are based on a gel that filles the nanoscalic inter-cellular space between the corneocytes. This gel is an important factor in the defence against adhesive glycoconjugates and organisms, that may negatively influence health and hydrodynamic demands of the dolphin. It was our aim to measure the rheological properties of the gel in order to confirm its viscoelastic behaviour predicted from our previous findings.Untreated fresh frozen skin samples of the Pilot Whale and centrifugates of mechani-cally ablated corneocytes were prepared for cryo-scanning electron microscopy (see Baum et al 2000 Aquatic Mammals 26:7). We examined the surface sculptures of the samples and documented different grades of polymerization seen in the centrifugates. Changes in viscoelasticity of the centrifugates were immediately after centrifugation monitored by means of a stress-controlled rheometer (Haake RS 150) with cone-and-plate geometry (35 mm, apex angle 1°) under oszillatory shear conditions.When centrifugates polymerized, their surface morphology appeared similar to the sur-faces of the untreated fresh skin samples. The gelation kinetics measured confirm that the centrifugates underwent polymerization within 2.5 - 3 hours after processing. At the beginning of the experiments, the high fluctuating pattern of the storage modul GŽ showed the presence of performed aggregates, which were destroyed by the oszillating force. After 2.5 - 3 hours new aggregates built up a gel. We found that in vitro the gela-tion terminates in a duroplastic gel, indicating gelation based on covently cross-linked network bridges.We thank Dr. D. Bloch and Dr. H.-P. Joensen, University of the Faroe Islands, for their help in specimen collection from legal harvest. This study was supported by a grant of the Deutsche Forschungsgemeinschaft (ME 1755/ 1-1).
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Average nanorough skin surface of the Pilot Whale (Globicephala melas, Delphinidae): Considerations on the self-cleaning abilities based on nanoroughness
Marine Biology, 2002Co-Authors: C Baum, L. G. Fleischer, Ralph Stelzer, Wilfried Meyer, D. SiebersAbstract:In aquatic environments, the biofouling process is assumed to initiate from the conditioning layer of absorbed organic carbon residues on wetted surfaces. Microfouling organisms attach to this conditioning layer, building up a biofilm on which further biofouling proceeds. In dolphins, biofouling reduces hydrodynamic efficiency and may negatively affect health if not managed. In the present study we examined the skin surface of the Pilot Whale (Globicephala melas). Employing cryo-scanning electron microscopic techniques combined with various sample preparations, the skin displayed an average nanorough surface characterized by a pattern of nanoridge-enclosed pores; the average pore size (approximately 0.20 µm2) was below the size of most marine biofouling organisms. Further, the implications of this type of surface to the self-cleaning abilities of the skin of Pilot Whales are discussed, based on reduced available space for biofouler attachment, the lack of any particular microniches as shelters for biofoulers, and the challenges of turbulent water flow and liquid–air interfaces during surfacing and jumping of the dolphin.
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a covalently cross linked gel derived from the epidermis of the Pilot Whale globicephala melas
Biorheology, 2002Co-Authors: Christof Baum, L. G. Fleischer, W Meyer, D Roessner, D. SiebersAbstract:: The rheological properties of the stratum corneum of the Pilot Whale (Globicephala melas) were investigated with emphasis on their significance to the self-cleaning abilities of the skin surface smoothed by a jelly material enriched with various hydrolytic enzymes. The gel formation of the collected fluid was monitored by applying periodic-harmonic oscillating loads using a stress-controlled rheometer. In the mechanical spectrum of the gel, the plateau region of the storage modulus G' ( 120 Pa) were independent of frequency (omega = 43.98 to 0.13 rad x s(-1), tau = 15 Pa, T = 20 degrees C), indicating high elastic performance of a covalently cross-linked viscoelastic solid. In addition, multi-angle laser light scattering experiments (MALLS) were performed to analyse the potential time-dependent changes in the weight-average molar mass of the samples. The observed increase showed that the gel formation is based on the assembly of covalently cross-linked aggregates. The viscoelastic properties and the shear resistance of the gel assure that the enzyme-containing jelly material smoothing the skin surface is not removed from the stratum corneum by shear regimes during dolphin jumping. The even skin surface is considered to be most important for the self-cleaning abilities of the dolphin skin against biofouling.
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a zymogel enhances the self cleaning abilities of the skin of the Pilot Whale globicephala melas
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2001Co-Authors: Christof Baum, Wilfried Meyer, D. Siebers, D Roessner, L. G. FleischerAbstract:Enzyme activity in the stratum corneum of the Pilot Whale Globicephala melas was investigated employing colorimetric enzyme screening assays combined with NATIVE PAGE, size exclusion chromatography (SEC) and histochemical staining procedures. Applying different substrates, several enzymes were detected. The histochemical demonstration of some selected hydrolytic enzymes enriched in the stratum corneum showed high extracellular accumulation. As demonstrated by size exclusion chromatography, high molar mass aggregates were built up from a glycoprotein-rich 20–30-kD fraction. Using NATIVE PAGE experiments under non-reducing conditions, a selection of five degrading enzymes was recovered within the above-reported aggregates. Activity of extracellular aggregate-attached enzymes in the superficial layer of the stratum corneum exhibited no remarkable decrease potentially resulting from self-degradation. We thus conclude that due to their enclosure within the microenvironment of aggregates, a zymogel is formed and autolysis of the stratum corneum is reduced. With respect to the skin surface, the zymogel with hydrolytic activities covering major parts of it enhances the self-cleaning abilities of the skin of the Pilot Whale based on physical pre-requisites by hydrolyzing adhesive glycoconjugates of settling biofouling organisms considered as primary steps in fouling.
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a zymogel enhances the self cleaning abilities of the Pilot Whale globicephala melas
EPIC3Comparative biochemistry and physiology a-molecular and integrative physiology 130 pp. 835-847, 2001Co-Authors: Christof Baum, L. G. Fleischer, Ralph Stelzer, W Meyer, D. SiebersAbstract:Summary. Enzyme activity in the stratum corneum of the Pilot Whale Globicephala melas was investigated employing colorimetric enzyme screening assays combined with NATIVE PAGE, size exclusion chromatography (SEC) and histochemical staining procedures. Applying different substrates, several enzymes were detected. The histochemical demonstration of some selected hydrolytic enzymes enriched in the stratum corneum showed high extracellular accumulation. As demonstrated by size exclusion chromatography, high molar mass aggregates were built up from a glycoprotein-rich 20-30 kD fraction. Using NATIVE PAGE experiments under non reducing conditions, a selection of five degrading enzymes was recovered within the above-reported aggregates.Activity of extracellular aggregate-attached enzymes in the superficial layer of the stratum corneum exhibited no remarkable decrease potentially resulting from self-degradation. We thus conclude that due to their enclosure within the micro-environment of aggregates a zymogel is formed and autolysis of the stratum corneum is reduced. With respect to the skin surface, the zymogel with hydrolytic activities covering major parts of it enhances the self-cleaning abilities of the skin of the Pilot Whale based on physical prequesites by hydrolysing adhesive glycoconjugates of settling biofouling organisms considered as primary steps in fouling.
Paula Mendezfernandez - One of the best experts on this subject based on the ideXlab platform.
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an assessment of contaminant concentrations in toothed Whale species of the nw iberian peninsula part ii trace element concentrations
Science of The Total Environment, 2014Co-Authors: Paula Mendezfernandez, Lynda Webster, Tiphaine Chouvelon, Paco Bustamante, Marisa Ferreira, Angel F Gonzalez, Alfredo Lopez, Colin F MoffatAbstract:Abstract Concentrations of Ag, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, V and Zn were investigated in the liver and kidney of the five most common toothed Whales off the Northwest Iberian Peninsula (NWIP), specifically common dolphin, long-finned Pilot Whale, harbour porpoise, striped dolphin and bottlenose dolphin. Differences were observed in the bioaccumulation of the above elements between the five species. The differences are probably related to biological factors such as age and sex and/or to ecological factors specific to each species such as feeding habits or bioavailability of the various elements. However, no significant relationship was observed between element accumulation and sex. Pilot Whale and striped dolphin showed the highest concentrations of renal Cd and the highest concentrations of hepatic Hg and Se, while bottlenose dolphin showed the highest concentrations of Hg in kidneys. An analysis of inter-elemental relationships showed strong positive correlations between Hg and Se in the five species, however most individuals have Hg:Se molar ratio less than 1:1 indicating an excess of Se compare to Hg. This result, probably reflect the high proportion of young animals in the sample available for this study and/or that these animals had a good health status. We also observed a positive correlation in striped dolphins between Cd and Cu and between Cd and Zn in kidneys. In addition, comparing with other studies world-wide, the element concentrations (Hg and Cd) found in Iberian toothed Whales indicate that these populations are not specially threatened by Hg and Cd exposure in the area.