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  • 1
    Electronic Resource
    Electronic Resource
    Histopathological, hematological, condition-factor, and organ weight changes associated with selenium accumulation in fish from Belews Lake, North Carolina (1984)
    Springer
    Archives of environmental contamination and toxicology 13 (1984), S. 153-162 
    Details
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract Green sunfish (Lepomis cyanellus) were collected from two study sites in Belews Lake, North Carolina, for assessment of correlations between several biological parameters and bioaccumulation of selenium. The fish had elevated concentrations of selenium in the hepatopancreas (liver) and exhibited histopathological and other manifestations of selenium poisoning. Condition-factors of Belews Lake fish were significantly correlated with selenium concentrations in hepatopancreas and skeletal muscle, indicative of capillary permeability changes and resultant edema, supported by the occurrence of significantly increased hepatopancreas-weight-to-body weight ratios in the fish having the higher tissue selenium levels. Gill lamellae were noticeably swollen and vacuolated. Hematocrits of the selenium-contaminated fish were significantly lower than those of the reference fish. The hepatopancreas exhibited lymphocyte infiltration, vacuolation of parenchymal hepatocytes around the central veins, and increased numbers of Kupffer cells. The mesonephros exhibited focal intra-capillary proliferative glomerulonephritis. Hearts showed swollen, inflammatory cell-filled pericardial spaces, diagnosed as possible uremia-induced pericarditis. Ovaries in fish with the higher liver selenium levels exhibited numerous necrotic and ruptured egg follicles. These conditions were observed in the Belews Lake Site 2 fish, but did not occur in reference green sunfish, nor did they occur consistently in fish from the less-contaminated Belews Lake Site 1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01055872
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  • 2
    Electronic Resource
    Electronic Resource
    Selenium accumulation and cytotoxicity in teleosts following chronic, environmental exposure (1982)
    Springer
    Bulletin of environmental contamination and toxicology 29 (1982), S. 688-696 
    Details
    ISSN: 1432-0800
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01606108
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  • 3
    Electronic Resource
    Electronic Resource
    Hematological dyscrasia in teleosts chronically exposed to selenium-laden effluent (1983)
    Springer
    Archives of environmental contamination and toxicology 12 (1983), S. 135-141 
    Details
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract Lepomis microlophus (redear sunfish) were collected from Martin Lake, an east Texas reservoir, as well as a reference lake 8 km upstream in the same drainage system. Martin Lake received aqueous selenium-laden effluent from electrical generator plant systems used to collect fly ash, scrubber sludge, and bottom ash; the reference lake received no such effluent (Texas Parks and Wildlife Department, unpublished report). Neutron activation analysis was used to monitor selenium levels in the hepatopancreas (i.e., the liver and associated, disseminated exocrine pancreas), which is one of the major organs used in monitoring selenium exposure. Fish collected from areas adjacent to the selenium-discharge sites in Martin Lake accumulated about 19.8 ppm in the hepatopancreas, compared to approximately 8.4 ppm for fish collected further from the discharge site. Reference redear sunfish accumulated normal levels of 1.8 ppm in the hepatopancreas. Hematological abnormalities were most severe for fish collected from areas adjacent to the selenium discharge site. These abnormalities included altered leukocyte distribution with elevated numbers of hemoblasts, reduced hematocrits, lower hemoglobin concentrations, slightly reduced numbers of erythrocytes, 12% and 23% reductions in mean corpuscular hemoglobin concentration (MCHC) and mean corpuscular volume (MCV), respectively, and microcytic, poikilocytic erythrocytes with elevated numbers of nuclear shadows. These data present a striking illustration of a case in which the hematological characteristics of a freshwater teleost were correlated with selenium accumulation in a critical organ following chronic selenium exposure. Hematological data provided a sensitive indicator of the severity of the impact of selenium-laden generator plant effluent on this teleost species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01059571
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  • 4
    Electronic Resource
    Electronic Resource
    Prey capture and structure of the visual space of an insect that hunts by sight on the litter layer (Notiophilus biguttatus F., Carabidae, Coleoptera) (1981)
    Springer
    Behavioral ecology and sociobiology 8 (1981), S. 91-97 
    Details
    ISSN: 1432-0762
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The carabid beetle Notiophilus biguttatus hunts springtails and mites by visual cues. The preycapture behaviour of the beetle and the escape behaviour of the springtails were analysed by means of highspeed films. N. biguttatus has between 900 and 1250 ommatidia in each compound eye. The visual space covers ca. 200° in the horizontal plane, with a binocular overlap of no more than 74°. The “fovea’, the part of the eye where the pseudopupil is largest, points straight ahead of a beetle in its normal posture. The structure of the visual space was determined from measurements of the optical axes in the horizontal plane (plane of fixation) over the middle of the eye. Because of the slanted position of the ommatidia under the cornea, the optical axes point more towards the front or the back of the animal than do the anatomical axes. The optical axes were used to construct the binocular visual space in the horizontal plane. The point E ∞, to which an estimation of distance is possible, lies on the midline 42.6 mm away from the front edges of the eyes. Resolution rapidly decreases with increasing distance, particularly depth resolution. At a distance corresponding to that from which the beetle attacks its prey, depth and width resolution correspond roughly to the dimensions of the smallest prey animals. The smallest measured directional corrections made by the beetle prior to attack (2°–3°) correspond approximately to the divergence angles in the fovea (ΔΦ h=2.2°), and the smallest measured distance correction prior to attack (0.2 mm) corresponds approximately to the depth resolution at attack distance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00300820
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  • 5
    Electronic Resource
    Electronic Resource
    Ultrastructure of a specialized, thrust-sensitive, insect mechanoreceptor: Stimulus-transmitting structures and sensory apparatus in the rostral horns of Notiophilus biguttatus (1982)
    Springer
    Cell & tissue research 226 (1982), S. 337-354 
    Details
    ISSN: 1432-0878
    Keywords: Insect mechanoreceptors ; Stimulus-transmitting structures ; Tubular body ; Evolution of mechanoreceptors ; Prey capture ; Beetles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. High-speed film recordings show that larvae of the beetle Notiophilus biguttatus, when attacking a prey, close their mandibles once the prey has been touched by two paired conical processes of the clypeolabrum (rostral horns). 2. In the third larval stage, the horns of one pair are about 140 μm long, those of the other pair about 50 μm. In each horn, a mechanosensitive hair is inserted into the distal portion. In the long horns, the hair is 35 μm long, in the short horns only 3.5 μm. Only the tips of the hairs are visible externally. Their shafts are enclosed within a cuticular collar, which makes up the walls of the horns. The cleft between the hair shaft and the surrounding collar is only about 0.1–0.2 μm wide. A sensory receptor cell is connected to each hair, which is characterized as a mechanoreceptor by the presence of a tubular body. 3. From structural characteristics, it can be deduced that the sensory receptor cell is stimulated not by axial displacement of the hair but rather by tilting movements, which lead to a transverse compression of the dendrite. 4. Geometric determinations from longitudinal sections demonstrate that hair-shaft deflections are limited to only about 20 min of arc in the long horns. The short horn sensory hairs can be deflected to a maximum of about 2°. The maximal displacement of the cuticular lever arm at the level of the tubular body and the values calculated for movement per degree of hair-shaft deflection lie within the normal range for mechanosensitive hairs (Table 1). 5. Considering their structural peculiarities, the long-horn receptors seem to be thrust-sensitive and to react to ramp stimuli of 20 min of arc in an all-or-nothing fashion. The short-horn receptors could react to graded hair-shaft deflections. 6. The main structural specialization of the rostral horn mechanoreceptors in evolution is the elongation of the socket region to form a cuticular collar around the sensory hair.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218364
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