| 1. |
- Elofsson, Rolf, et al.
(författare)
-
The anostracan rhabdom and the basement membrane. An ultrastructural study of the Artemia compound eye (Crustacea)
- 1975
-
Ingår i: Acta Zoologica. - : Wiley. - 0001-7272 .- 1463-6395. ; 56, s. 141-153
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Tidskriftsartikel (refereegranskat)abstract
- The ommatidia of the compound eyes of Artemia salina L. are normally composed of four crystalline cone cells containing glycogen. The cells are enveloped by two so-called “cellules épidermiques juxta-cristallines”. There are also six pigmented retinula cells, all contributing to the rhabdom.A peculiar feature of the Artemia crystalline cone cells is that their elongated parts, the so-called cone cell roots, widen and flatten proximally, forming interdigitating “endfeet”. The basement membrane thus consists of a cellular portion combined with the basal lamina.The main mass of the rhabdom of the Artemia eye is built up by five retinula cells, two contributing a smaller part. The microvilli are oriented in four directions, two being orthogonal. The sixth cell contributes on two small portions to the rhabdom in the distalmost and a more proximal position. The rest of it runs axon-like outside the omnatidium. Where the sixth cell wedges in, the direction of the microvilli is changed and has no orthogonal pattern.Two rhabdom types of compound eyes are distinguished: the decapod or banded or layered rhabdom: and the anostracan rhabdom with continuous rhabdomeres.
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| 2. |
- Nilsson, Dan-E, et al.
(författare)
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The compound eye of Leptodora kindtii (Cladocera): : An adaptation to planctonic life.
- 1983
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Ingår i: Cell and Tissue Research. - 1432-0878. ; 230, s. 40-410
-
Tidskriftsartikel (refereegranskat)abstract
- Each of the approximately 500 ommatidia in the compound eye of the cladoceran crustacean Leptodora kindtii has a crystalline cone consisting of five cells. Five retinula cells are also present, one of which contributes to the distal 1–2 μm of the rhabdom only; the other four retinula cells form a continuous rhabdom. Throughout the rhabdom its cross section displays two separate halves with the axis of the microvilli in one half perpendicular to that in the other (orthogonal pattern). Interferometric analysis of the refractive index of the crystalline cone revealed an inhomogeneous system with one distal and one proximal gradient. The gradient system was found to exclude rays entering from adjacent facets, thus maintaining the optical isolation. Consequently, these optics replace distal screening pigment, which is absent in the eye. The long and unscreened crystalline cones give rise to an almost transparent eye in conformity with the overall transparency of this planktonic animal.The morphological characteristics of the eye of this species deviate from other cladoceran eyes, but the optical design closely resembles that of some pelagic marine amphipod crustaceans.
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| 3. |
- Nässel, Dick, et al.
(författare)
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Neuronal connectivity patterns in the compound eyes of Artemia salina and Daphnia magna (Crustacea: Branchiopoda)
- 1978
-
Ingår i: Cell and Tissue Research. - 1432-0878. ; 190, s. 435-457
-
Tidskriftsartikel (refereegranskat)abstract
- The neuronal types and patterns in the visual system of the species Artemia salina and Daphina magna have been studied with the Golgi method and electron microscopy. The lamina contains five classes of neurons: photoreceptor axons, monopolar, centrifugal, tangential and amacrine neurons. The terminals of the receptor axons are distributed in two (A. salina) or three (D. magna) layers. The dilated terminals have an extensive and wide array of fine branches. One axon from each ommatidium bypasses the lamina and terminates in the medulla in A. salina. A. salina has four types of monopolar neurons, two of which are stratified, whereas in D. magna only two types are found, one of which is bistratified. Tangential T-neurons connect the lamina with the protocerebrum. D. magna has in addition one tangential T-neuron connecting both the lamina and the medulla with the protocerebrum. In both species monopolar-type centrifugal neurons connect the medulla and the lamina, whereas that of A. salina has a wide laminar distribution. Both species also have amacrine cells in the lamina. The medulla contains, besides those shared with the lamina, transmedullary neurons (two types in A. salina), amacrine cells and neurons originating in the protocerebrum.“Cartridge”-type synaptic compartments are lacking in the investigated species, although a periodic arrangement is discernible in the distal portion of the lamina of A. salina. The receptors from three types of specialized contacts in Artemia, one of which involves a dyad. D. magna has only one-to-one synapses. Neurosecretory fibres are absent in A. salina.
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| 4. |
- Odselius, Rolf, et al.
(författare)
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The basement membrane of the insect and crustacean compound eye: definition, fine structure and comparative morphology
- 1981
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Ingår i: Cell and Tissue Research. - 1432-0878. ; 216, s. 201-214
-
Tidskriftsartikel (refereegranskat)abstract
- The basement membrane of the compound eye of four insect species and three crustacean species was investigated employing electron microscopy. The basement membrane consists of an extracellular (basal lamina) and a cellular portion, the latter being composed of the flattened terminal extensions of cone cells and accessory pigment cells in insects and distal pigment cells in crustaceans. Other cells can also contribute to the basement membrane. It is thus a complex structure in all well-developed compound eyes. The cellular contributions vary in different species and were found to correlate to specific taxonomic units.
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| 5. |
- Andersson, Anders, et al.
(författare)
-
The epidermal indeterminate cell- a special cell type?
- 1981
-
Ingår i: Acta dermato-venereologica. Supplementum. - 0365-8341. ; 99, s. 41-48
-
Tidskriftsartikel (refereegranskat)abstract
- Electron microscopy of normal human epidermiscomprising very large series of sections in combination withtilting of the sections has revealed that all "indeterminatecells" carry the specific markers of either melanocytes orLangerhans cells. The term "indeterminate cells" can thusbe abandoned. In addition, it is suggested that an epidermaldendritic cell lacking specific markers in the section underobservation can be characterized by the amount and distributionpattern of its microfilaments, an additional criterionbeing that the melanocytes carry a ciliunu
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| 6. |
- Aramant, Robert, et al.
(författare)
-
Distribution of monoaminergic neurons in the nervous system of non-Malacostracan crustaceans
- 1976
-
Ingår i: Cell and Tissue Research. - 1432-0878. ; 166, s. 1-24
-
Tidskriftsartikel (refereegranskat)abstract
- A comparative investigation of the distribution of monoaminergic neurons in non-malacostracan crustaceans was performed with the histochemical fluorescence method of Falck-Hillarp.Two fluorophores were found: the more widespread of the two emits a green fluorescence; and the more sparsely distributed emits a yellow to brown-yellow fluorescence.Specific green fluorescent areas were shown to exist in the protocerebrum. The central body and the optic ganglia of the compound eye (where present) are always fluorescent. Moreover, the centre of the nauplius eye may have a green fluorophore, as in ostracods, and a neuropile area, here called the frontal area. These neuropile centres are known from ordinary histological studies of the nervous system. In addition, there are specific monoaminergic centres, such as the so-called dorsal area of phyllopods and anostracans as well as the copepod specific areas. Specific monoaminergic areas appear in the deutocerebrum and the suboesophageal ganglion where they are particularly well developed.Presumed sensory neurons in the cavity receptor organ of Artemia salina are shown to be monoaminergic. Monoaminergic sensory neurons have not been described previously in Arthropods.Presumed motor innervation of hind-gut and trunk muscles is also found, and it is concluded that in crustaceans neurons of every type (sensory, internuncial, motor) may be monoaminergic.
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| 7. |
- Aramant, Robert, et al.
(författare)
-
Monoaminergic neurons in the nervous system of crustaceans.
- 1976
-
Ingår i: Cell and Tissue Research. - 1432-0878. ; 170, s. 231-251
-
Tidskriftsartikel (refereegranskat)abstract
- Certain neurons in the nervous system of the malacostracan crustaceans give rise to a predominantly green and a sparse yellow fluorophore in the histochemical fluorescence method of Falck-Hillarp. The same applies to the whole of Crustacea. The green fluorophore is probably a catecholamine; the yellow to brown-yellow has not yet been identified.The biogenic amine responsible for the green fluorescence, besides being found in diffusely distributed fibres, also appears in distinct areas of fibre concentrations in the central nervous system. The protocerebrum of the malacostracans contains three areas: the central body and two areas in the top of the brain, one anterior and one posterior. The latter two are not recognized as separate areas in ordinary histological preparations. In addition, the optic neuropiles are fluorescent, some with a distinct stratification of the fluorophore. The deuto and tritocerebrum and the ventral nerve cord also contain monoaminergic neurons. Of the brightly fluorescent areas in the whole of Crustacea, only the central body consistently exists in all species. The other areas of concentrated fluorescent neuropile are restricted to smaller taxonomic units and differ from each other. p The monoaminergic neurons in Crustacea are sensory, motor, and internuncial, and also belong to a fourth type which mimics the neurosecretory neurons in neurohaemal organs. Only one example of a monoaminergic sensory neuron is known (in Anemia, a non-malacostracan, Aramant and Elofsson 1976), a few motor and a few neurosecretory mimics (the latter in malacostracans). Most are internuncials.
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| 8. |
- Axelsson, S, et al.
(författare)
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In vitro-uptake of L-Dopa and catecholamines into the epidermal Langerhans cell
- 1978
-
Ingår i: Acta dermato-venereologica. Supplementum. - 0365-8341. ; 79, s. 31-35
-
Tidskriftsartikel (refereegranskat)abstract
- The Langerhans cells are capable of taking up L-dopa and the catecholamines dopamine and noradrenaline when exposed to these substances in vitro. Within the cell L-dopa is found in the cytoplasm as well as in the nucleus, whereas the catecholamines are confined to cytoplasmic granules. The L-dopa uptake is most probably carrier-mediated and the hypothesis is brought forward that L-dopa enters the cell by exchange diffusion. At present little is known about the nature of the amine uptake mechanism.
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| 9. |
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| 10. |
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| 11. |
- Carlberg, Mats, et al.
(författare)
-
Presence of 3 4-dihydroxyphenylalanine and 3,4,5-trihydroxyphenylalanine in a coelenterate nervous system: possible tyrosinase-mediated accumulation.
- 1987
-
Ingår i: Neurochemistry International. - : Elsevier BV. - 0197-0186. ; 11, s. 161-167
-
Tidskriftsartikel (refereegranskat)abstract
- 3,4-dihydroxyphenylalanine (DOPA), 3,4,5-trihydroxyphenylalanine (5-OH-DOPA), 5-S-cysteinylDOPA (5-SC.D) and 2-S-cysteinylDOPA (2-SC.D) in the tentacles of the sea anemone, Metridium senile, were studied by the combined use of differential centrifugation of tissue homogenates, ultracentrifugation on sucrose density gradients, HPLC and electron microscopy. DOPA, 5-OH-DOPA and o-diphenol:O2 oxidoreductase (Tyrosinase) were enriched in fractions containing membranes and subcellular particles, and the cysteinylDOPAs in the cytosol fractions. Ultrastructurally studied fractions rich in DOPA and 5-OH-DOPA contained large numbers of highly osmium-reducing vesicles. Identical structures were localized in ectodermal nerves and epidermal sensory cells.The results suggest that previous findings of catecholderivatives in the tentacles of Metridium and other sea anemone species by histochemical methods, are explained by a tyrosinase-based accumulation of DOPA and 5-OH-DOPA in the ectodermal nerve net. These substances are confined in specific compartments (vesicles) in the neurons and sensory cells.
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| 12. |
- Dubbels, R, et al.
(författare)
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N-acetylation of arylalkylmines (serotonin and tryptamine) in the crayfish brain.
- 1989
-
Ingår i: Comparative Biochemistry and Physiology Part - C: Toxicology and Pharmacology. - : Elsevier BV. - 1532-0456 .- 0306-4492. ; 93, s. 307-312
-
Tidskriftsartikel (refereegranskat)abstract
- 1. The presence of N-acetyltransferase in the crayfish brain (Pacifastacus leniusculus) was investigated. The arylalkylamines tryptamine and 14C-serotonin, are acetylated by crayfish brain homogenates with the acetyl donors 3H-acetyl coenzyme A and N, S-diacetylcysteamine, respectively.2. Resolution of serotonin metabolites by thin layer chromatography (chloroform/methanol/glacial acetic acid, 93 + 7 + 1 and ethyl acetate) revealed only one radioactive product (N-acetylserotonin, Rf 0.31) after enzymatic reaction. For example, melatonin and 5-hydroxyindole acetic acid could not be detected.3. This was also confirmed by reversed phase high performance liquid chromatography indicating the absence of monoamine oxidase and hydroxyindole-O-methyltransferase activity under the experimental conditions used.4. Inhibitory studies with cystamine suggest the involvement of heat sensitive disulfide compounds in the regulation of crayfish brain-N-acetyltransferase.5. N-acetylation seems to be a major pathway in the metabolism of biogenic amines in the crayfish central nervous system.
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| 13. |
- Dyakonova, Varvara, et al.
(författare)
-
Anatomical basis for interactions of enkephalins with other transmitters in the CNS of a snail.
- 1995
-
Ingår i: Journal of Comparative Neurology. - : Wiley. - 0021-9967 .- 1096-9861. ; 361, s. 38-47
-
Tidskriftsartikel (refereegranskat)abstract
- Immunocytochemical techniques for double staining were employed to investigate the morphological basis for interactions between enkephalins and other neuroactive compounds in the behavior of the gastropod mollusc Cepaea nemoralis. Coexistence of each of the two enkephalins with FMRFamide, serotonin or GABA-like immunoreactivity was found in certain neurons in cerebral, parietal, and pedal ganglia. Tyrosine hydroxylase-immunoreactive neurons were occasionally seen in close apposition to, but never colocalized with, the enkephalins. A comparison between these anatomical observations and previous behavioral studies suggests that in gastropod molluscs cotransmission of enkephalins with classical transmitters may, at least partly, reflect synergism of these substances in the control of definite behavioral programs
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| 14. |
- Dyakonova, V. E., et al.
(författare)
-
Complex avoidance behavior and its neurochemical regulation in the land snail Cepea numerals
- 1995
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Ingår i: General Pharamacology. - 0306-3623. ; 26, s. 773-777
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Tidskriftsartikel (refereegranskat)abstract
- .1. In hot plate experiments, the pulmonate land snail Cepaea nemoralis displays a biphasic passive/active avoidance behaviour composed of retraction and subsequent searching mediated by antagonistic muscular systems. The switch, between the behaviours, is under neuronal control.2.2. Leu- and met-enkephalin, as well as FMRFamide-antiserum, attenuated the retraction response and potentiated the searching behaviour. Opposite effects were achieved by injection of antisera to the enkephalins.3.3. Both retraction and searching behaviours were potentiated by 5-HT. Methysergide antagonized the effects of the enkephalins on the searching behaviour.4.4. We conclude that endogenous opioids act antagonistic to FMRFamide in the neuronally controlled switch between passive and active avoidance behaviour.
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| 15. |
- Dyakonova, V, et al.
(författare)
-
Effects of naloxone on c-jun/AP-1 in MET-enkephalin- and FMRFamide-immunoreactive neurons of a gastropod snail
- 1999
-
Ingår i: Acta Biologica Hungarica. - 0236-5383. ; 50:1-3, s. 43-54
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Tidskriftsartikel (refereegranskat)abstract
- 1. Opioid- and FMRFamide (FMRFa)-ergic systems are believed to play antagonistic behavioral roles in both higher and lower animals. In our previous experiments on a snail, behavioral choice has been demonstrated to be dependent on a balance between FMRFa and enkephalins [7]. Here, we examined if the disturbance of the balance causes changes in the activity of both systems. Opiate receptor blocker naloxone was applied and its effect on c-jun expression of met-enkephalin (MEnk)- and FMRFa-ergic neurons was examined immunocytochemically in terrestrial gastropod snail Cepaea nemoralis. 2. In control, untreated snails, central neurons with c-jun/AP-1-like-immunoreactivity were found to occur. These included MEnk-, FMRFa- and 5HT-immunoreactive (-ir) neurons, as was revealed by double-labelling. 3. After treatment with naloxone for 4 h, the following changes were observed: (i) increase in the number of MEnk-ir neurons; increase in the number of neurons showing c-jun/AP-1 and MEnk double-labeling; (ii) disappearance of c-jun/AP-1-immunoreactivity from some FMRFa-ir neurons. 4. It is suggested that immediate early genes are involved in the mechanisms responsible for the reciprocal regulation of the opioid and antiopioid neuropeptide systems.
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| 16. |
- Elofsson, Rolf
(författare)
-
5-HT-like immunoreactivity in the central nervous system of the crayfish Pacifastacus leniusculus
- 1983
-
Ingår i: Cell and Tissue Research. - 1432-0878. ; 232, s. 221-236
-
Tidskriftsartikel (refereegranskat)abstract
- An immunocytochemical technique with the use of three different antibodies raised against serotonin was applied to localize the immunoreactive neurons in the central nervous system of the crayfish, Pacifastacus leniusculus. Immunoreactive neurons were found in three optic ganglia (medulla externa, interna and terminalis). They appeared in three layers of the medulla externa and interna. The medulla terminalis displayed three prominent groups of immunoreactive perikarya and mainly marginal immunoreactive fibres. Immunoreactive areas of the brain comprised the protocerebral bridge, central body, paracentral lobes and two loci in the anterior portion of the protocerebrum, i.e., the terminal areas for immunoreactive fibres from the optic centres. The olfactory lobes showed a specific immunoreactive pattern. In addition, diffusely and sparsely distributed immunoreactive fibres were found throughout the brain. The immunoreactive neurons are largely localized in the same areas of the central nervous system as the catecholaminergic neurons although some distinct differences occur.
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| 17. |
- Elofsson, Rolf, et al.
(författare)
-
A catecholaminergic neuron connecting the first two optic neuropiles (lamina ganglionaris and medulla externa) of the crayfish Pacifastacus leniusculus
- 1977
-
Ingår i: Cell and Tissue Research. - 1432-0878. ; 182, s. 287-297
-
Tidskriftsartikel (refereegranskat)abstract
- The crustacean optic neuropiles, the lamina ganglionaris and especially the medulla externa, show a specific pattern of green fluorescence with the fluorescence histochemical method of Falck-Hillarp. Normally, only the terminals and the cell bodies fluoresce, but in reserpine-treated animals exogenous catecholamines are taken up by the whole adrenergic neuron and are thus visualized as a whole. Incubating crayfish optic neuropiles in dopamine or α-methylnoradrenaline after reserpine treatment demonstrated a tangential neuron connecting the lamina and the medulla externa. The morphology of this tangential neuron differs from the two types of tangential neurons, Tan1 and Tan2, previously characterized with Golgi techniques. The catecholaminergic neuron thus constitutes a third tangential neuron type.
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| 18. |
- Elofsson, Rolf, et al.
(författare)
-
A complex sensory organ in the nose skin of the prosimian primate Lemur catta.
- 2015
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Ingår i: Journal of Morphology. - : Wiley. - 1097-4687 .- 0362-2525. ; 276:6, s. 649-656
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Tidskriftsartikel (refereegranskat)abstract
- Most mammals have nose tips covered by glabrous skin, a labronasal area, or rhinarium. The surface of the rhinarium of Lemur catta has a dermatoglyphic pattern consisting of epidermal domes. Below the domes, epidermal pegs dip down into the dermis. In and below the tip of the epidermal peg, a complex sensory organ is found. It consists of an association of innervated Merkel cells, lamellate (Pacini-like) bodies with a central nerve, and a ring of unmyelinated nerve endings in the epidermis. The Merkel cells are situated basally in the epidermis and the lamellated bodies just below the epidermis. The unmyelinated nerve endings related to the organ ascend in a circle straight through the epidermis ending below the corneal layer. From these nerve terminals, horizontal spikes enter the keratinocytes. The three components occur together forming an organ and are innervated from a common nerve plexus. The morphology of the complex sensory organ of the lemur shares most crucial components with Eimer's organs in moles, echidna, and platypus, while some structures are lacking, for example, the specific central pillar of keratinocytes, the cuticular cap, and a central unmyelinated fiber. The presence of the essentials of an Eimer's organ in many mammals suggests that a wider definition is motivated. J. Morphol., 2015. © 2015 Wiley Periodicals, Inc.
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| 19. |
- Elofsson, Rolf, et al.
(författare)
-
A layered rhabdom in an isopod (Crustacea). A case of convergent development.
- 1977
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Ingår i: Zietschrift für mikroskopische anatomische Forschung. ; 91, s. 415-420
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Tidskriftsartikel (refereegranskat)abstract
- The isopod species Astacilla longicornis (Sowerby) has a layered rhabdom, which is the first case reported in isopod crustaceans. The rhabdom comprises the rhabdomeres of six retinular cells. It is surrounded by an extracellular palisade. Usually, palisades are intracellular in arthropods. A layered rhabdom is found in taxonomically widely separated groups within the Arthropoda and no intermediate forms are found between the different, highly specialized rhabdom types present. It is concluded that the layered rhabdom represents an example of convergent development.
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| 20. |
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| 21. |
- Elofsson, Rolf, et al.
(författare)
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A new type of somatosensory organ in the nasolabila skin of the dog
- 2020
-
Ingår i: Journal of Morphology. - : Wiley. - 1097-4687 .- 0362-2525. ; 281, s. 413-419
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Tidskriftsartikel (refereegranskat)abstract
- A new morphological type of somatosensory organ is described. It is found in the glabrous skin of the dog nose (rhinarium or planum nasale) and situated in dermis papillae. The otherwise thick epidermis forms a thin window above the organ. There are only a few layers of keratinocytes in the window and the corneocytes are much thinner than elsewhere. The organ consists of highly branching cells that wrap naked nerve endings emanating from myelinated nerve fibers originating in the outer dermal nerve plexus. The structure entirely fills the top of the dermal papilla. The intercellular spaces of the organ and its surroundings are occupied by an extended areolar basal lamina.
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| 22. |
- Elofsson, Rolf
(författare)
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A Non-Ciliary Receptor in the Mandible of a Mystacocarid Crustacean, Derocheilocaris Typica
- 2015
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Ingår i: Journal of Crustacean Biology. - 0278-0372. ; 35:4, s. 504-510
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Tidskriftsartikel (refereegranskat)abstract
- The mystacocarid crustacean Derocheilocaris typica Pennak and Zinn, 1943 lives in sand interstices and is less than one mm long. It is unique among Arthropoda. It has sensory cells in the mandible, which lack cilia. The function as mechano- and/or chemo-receptors has been replaced by dendrites, the sensory cell protrusions carrying cilia. The dendrites swell, flatten, and fill the endite- a medial outgrowth from the mandible, which is the main masticating appendage. The dendrites have many contacts with the inside of the cuticle, which insures close proximity to the food outside the body. Another feature specific to D. typica is the reduced cilia in the cuspidate setae of the food handling appendages: first and second maxillae, and maxilliped. The remaining approximate 50 setae on the body, not related to food handling, conform to those of all arthropods.
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| 23. |
- Elofsson, Rolf, et al.
(författare)
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A novel ultrastructure on the corneocyte surface of mammalian nasolabial skin.
- 2016
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Ingår i: Journal of Mammalogy. - : Oxford University Press (OUP). - 0022-2372 .- 1545-1542. ; 97:5, s. 1288-1294
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Tidskriftsartikel (refereegranskat)abstract
- In many mammals, the skin of the rhinarium includes a thick epidermal layer. The skin surface can be smooth but can also display a structure formed of domes, ridges, and polygonal areas: a dermatoglyphic or rhinoglyphic pattern. Each structure consists of an easily visible, large area of the epidermis. The abdominal epidermis may or may not have a dermatoglyphic pattern. The abdominal skin examined in our study had no pattern and was consequently unstructured and smooth. The ultrastructural surface pattern is formed in the granular and corneous regions of nasal epidermis by desmosome protrusions projecting into adjacent keratinocytes. Complete retraction of the keratinocyte protrusions with desmosomes in the abdominal epidermis creates an unstructured, smooth surface. The cornification process differs morphologically in nasolabial and abdominal skin. In this study, we report a novel structure in the nose skin. It is related only to the surface of a single corneocyte (keratinocyte) and consists of submicrometer pores or furrows, an ultrastructure pattern. It is not related to the rhinoglyphic pattern. The nose skin can thus have 2 unrelated patterns. This structure seems to be widespread among the Mammalia. We suggest the function of the structure is to keep the rhinarium evenly moist.
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| 24. |
- Elofsson, Rolf
(författare)
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A peculiar kind of pigment cell in the compound eye of Lepisma saccharina L. (Thysanura)
- 1973
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Ingår i: Entomologica Scandinavica. Supplementum. - 0105-3574. ; 4, s. 87-90
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Tidskriftsartikel (refereegranskat)abstract
- The ultrastructure of the primary pigment cells of the compound eye of Lepisma saccharina is described. The cells are four in number. The pigment granules are contained in fingerlike protrusions from the pigment cells. These protrusions project into the enlarged basal lamina surrounding the ommatidial top. The large basal lamina could have given the impression of a cell (called corneagen) in the light microscope.
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| 25. |
- Elofsson, Rolf
(författare)
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A presumed new photoreceptor in copepod crustaceans.
- 1970
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Ingår i: Zeitschrift für Zellforschung und mikroskopische Anatomie. ; 109:3, s. 316-326
-
Tidskriftsartikel (refereegranskat)abstract
- A new photoreceptor in the Copepoda is described. The organ, previously called Gicklhorn's organ (Elofsson, 1966a), is paired and is usually situated beneath the cuticle of the front. Each member of the pair consists of two cells. From the anterolateral position, two nerves lead to the lateral part of the brain. No connexion with the nauplius eye is found. Each cell of the organ has microvilli, two nuclei, dictyosomes, and large cisternae of the endoplasmic reticulum. Except for the binucleated condition, the cells closely resemble the retinula cells of the copepod nauplius eye.It is concluded that, because of its independent position, the new photoreceptor is not a detached part of the nauplius eye. As there are no accessory structures present and no missing links so far known, it is doubtful whether it can be regarded as a vestigial compound eye. The most plausible hypothesis is that the new presumed photoreceptor is an independent structure without connexions either with crustacean compound or nauplius eyes.If the function of the nauplius eye is considered by itself the improvement contributed by the new organ is probably modest because of its low level of organization. Some experimental evidence on light reception in Copepods points to a possible function in response to directed light.
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| 26. |
- Elofsson, Rolf, et al.
(författare)
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A variation of pigmentation in the glabrous skin of dogs
- 2018
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Ingår i: Journal of Morphology. - : Wiley. - 0362-2525. ; 279:8, s. 1194-1198
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Tidskriftsartikel (refereegranskat)abstract
- The usual pigmentation pattern in mammalian skin consists of fixed melanocytes in the basal layer of the epidermis, supplying keratinocytes with melanosomes. We observed that the glabrous skin (rhinaria and footpads) of dogs deviates from this pattern. In dogs, melanocytes are found in both the dermis and epidermis. The epidermal melanocytes are situated in the intercellular spaces of the basal and spinous layers. They are characterized by a quantity of cytoplasm containing a centriole, also developing melanosomes, and in some cases annulate lamellae. There is a high frequency of closely apposed melanocytes in the epidermis. Melanosomes in different stages of formation are also abundant. The morphology of the glabrous skin of dogs suggests transport of melanocytes from the dermis into the epidermis and formation of melanosomes in the epidermis. A distributed and intense pigment formation may be necessary to achieve the black noses of many dog breeds and wild canids, as well as dark footpads despite heavy abrasion and rapid skin renewal.
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| 27. |
- Elofsson, Rolf
(författare)
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Brain and eyes of Zygentoma (Thysanura)
- 1970
-
Ingår i: Entomologica Scandinavica. Supplementum. - 0105-3574. ; 1, s. 1-20
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Tidskriftsartikel (refereegranskat)abstract
- The brain, the compound eyes and the ocelli are described for some zygentomid species. Special interest has been focused on Tricholepidion gertschii, a newly discovered, primitive species. The brain morphology shows great similarities in the general shape and in details within the whole suborder. The compound eyes of Tricholepidion gertschii and Lepisma saccharina resemble each other closely. The present investigation has shown that the zygentomid and pterygote compound eyes are similar in that there are no corneagen cells. The view that the compound eyes of the Zygentoma should constitute a connecting link between crustacean and insect compound eyes can no longer be maintained. Tricholepidion gertschii possesses three ocelli. Their structure stresses the connection between thysanurans and pterygote insects. In this connexion the homology of reduced ocelli is discussed and their nerve contacts reinvestigated.
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| 28. |
- Elofsson, Rolf, et al.
(författare)
-
Catcholaminergic salivary glands in Gammarus pulex (Crustacea, Amphipoda): An electron microscopic and microspectrofluorometric study
- 1978
-
Ingår i: Journal of Ultrastructure Research. - 0022-5320. ; 64, s. 14-22
-
Tidskriftsartikel (refereegranskat)abstract
- The type of gland (salivary gland) described here for the amphipod Gammarus pulex belongs to the tegumental glands, which have different structural characteristics. The present type, called rosette gland, is common in some crustaceans and is located in the ventral half of the head. The functional unit is a lobule of gland cells with a central-draining duct. Ducts from groups of lobules conjoin and terminate on the body surface at different points around and in the mouth and mouth parts. With the fluorescence histochemical method of Falck and Hillarp, specific green fluorescence was discerned centrally in the lobules and was confined to the gland cells. The spectral characteristics of the fluorescence, as revealed by microspectrofluorometric analysis, indicated either a mixture of dopamine and a presumed new catechol compound or the presence of two tautomeric forms either of dopamine or of a new catechol compound. Evidence of new catechol compounds with similar spectral characteristics has previously been found in the sensory cells of some invertebrates. The fluorescence distribution within the lobule coincides with the presence, ultrastructurally, of large dense vesicles in the gland cells. These dense vesicles occur in the predominant cell type, also characterized by a smooth endoplasmic reticulum. The other cell type in the lobules differs ultrastructurally by possessing a rough endoplasmic reticulum and a different vesicle type. No innervation of the salivary gland was perceived.
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| 29. |
- Elofsson, Rolf, et al.
(författare)
-
Catecholaminergic innervation of muscles in the hindgut of crustaceans
- 1978
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Ingår i: Cell and Tissue Research. - 1432-0878. ; 189, s. 257-266
-
Tidskriftsartikel (refereegranskat)abstract
- The crustacean species Pacifastacus leniusculus and Gammarus pulex were investigated by electron microscopy in a search for possible neuromuscular junctions in the hindgut, which has a rich supply of catecholaminergic fibres. True neuromuscular synapses were found in both species between nerve terminals containing dense-core vesicles (80–110 nm in diam.) and muscle fibres. We suggest that the dense-core vesicle terminals contain a catecholamine, and this is supported by ultrahistochemical tests for monoamines. Two types of junctions are found: one in which the nerve terminal is embedded in the muscle cell (both species) and one in which protrusions from the muscle cell meet nerve terminals (Pacifastacus). Gammarus pulex, which has only circular muscles in the hindgut, has only catecholaminergic innervation, whereas Pacifastacus leniusculus has circular and longitudinal muscles both with at least two types of innervation.
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| 30. |
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| 31. |
- Elofsson, Rolf, et al.
(författare)
-
Compound eyes of some deep-sea and fiord crustaceans
- 1977
-
Ingår i: Acta Zoologica. - : Wiley. - 0001-7272 .- 1463-6395. ; 58, s. 169-177
-
Tidskriftsartikel (refereegranskat)abstract
- The compound eyes of the deep-sea mysid Boreomysis scyphops and the two mysid species Amblyops abbreviata and Pseudomma affine, which are indigenous to deep fiords in Norway, have been investigated. The eye stalks are greatly transformed, but contain hypertrophied retinas. The ommatidia of all three species lack a dioptric apparatus, possessing only retinular cells, which are arranged in a cylinder-like fashion. Folds from the retinular cells project into the “cylinder” and are covered with microvilli. The arrangement is explained functionally by an increase in the photopigment-bearing surface as an adaptation to low-light intensities. The orderly arrangement of microvilli in most arthropod compound eyes has been lost, and the arrangement is thus multidirectional in these mysids. With the photopigment dipoles arranged along the microvillar axis, the disorderly arrangement of microvilli signifies a more efficient capture of non-polarized light. It is concluded that the mysid compound eyes show adaptations to low-light intensities probably acquired during the species' evolutionary descent into deep-sea habitats. Amblyops abbreviata and Pseudomma affine, belonging to genera with entirely transformed eyes and with an ultrastructure less “normal” than that of Boreomysis scyphops are believed to be earlier descendants into the deep-sea habitats than the latter species, which belongs to a genus in which most of the species have well-developed eyes.
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| 32. |
- Elofsson, Rolf, et al.
(författare)
-
Correlation of ultrastructure and chemical composition of crustacean chromatophore pigment
- 1973
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Ingår i: Journal of Ultrastructure Research. - 0022-5320. ; 44, s. 421-429
-
Tidskriftsartikel (refereegranskat)abstract
- Chromatophores, with chemically identified pigment, from the body and eyes of crustaceans were investigated ultrastructurally. Red carotenoid-, black ommochrome-, and white pteridine-containing chromatophores were found to have pigment granules of different morphological appearance.
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| 33. |
- Elofsson, Rolf, et al.
(författare)
-
Evidence for endocytotic mechanisms in the epidermal Langerhans cells.
- 1981
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Ingår i: Acta dermato-venereologica. Supplementum. - 0365-8341. ; 99, s. 29-39
-
Tidskriftsartikel (refereegranskat)abstract
- When the Langerhans cells (LC) are prepared forelectron microscopy with an osmotically balanced prefixative,they display their classical criteria, but in additionthey are provided with numerous microvilli and containpinocytotic vesicles. In cross-sections the specific discshapedgranules are visualized as rod-like profiles limited bya trilaminar membrane similar to the cell membrane. Inface-on projection the electron density of a single granule istoo low to permit its observation. It ts suggested that theracquet-shaped profile bounded by a non-trilaminar membrane,regarded as classical, is a fixation artifact. The viewis advanced that the Birbeck granules are formed by a processimplying a superimposition of membrane folds. Theoccurrence of phagocytosed melanosomes seems to be anormal phenomenon.The LC are highly activated in contact allergic dermatitis,as expressed by an increase in number, a polarizationof dendrites towards the surface and the appearance ofmembrane active zones characterized by intense membranefolding, combined with a formation of pinocytotic vesiclesand specific granules. Challenging sensitized skin withnickel leads to the occurrence of dark vesicles which probablylack a limiting membrane. It is concluded that the LCshow endocytotic activity and that they constitute animportant defense system in the epidermis, i.e., capable ofcapturing extracellular (endogenous or exogenous) materialvia different routes.
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| 34. |
- Elofsson, Rolf, et al.
(författare)
-
Evidence for new catecholamines or related amino acids in some invertebrate neurons
- 1977
-
Ingår i: Cell and Tissue Research. - 1432-0878. ; 182, s. 525-536
-
Tidskriftsartikel (refereegranskat)abstract
- In certain sensory neurons of many different invertebrate species, including the sea anemones. Metridium senile and Tealia felina and the crustacean Anemia salina, fluorophores are formed during the course of the fluorescent histochemical technique of Falck-Hillarp. The presumed catecholamine nature of the neuronal fluorogenic compound was investigated by microspectrofluorometry, and the spectral characteristics of the fluorescence in the taxonomically different species was found to be very similar (excitation maximum at 375 nm with a smaller peak or shoulder at 330 nm and sometimes a shoulder in the spectrum at 410 nm; emission maximum at 475 nm). The emission maximum coincides with that of the catecholamines and DOPA (475 nm). The excitation maximum (375 nm) directly after formaldehyde treatment, however, differs from that of the catecholamines and DOPA (410 nm), but is similar to the excitation maximum displayed by these catechol derivatives at acid pH. The spectral characteristics of the fluorophore in the sensory cells might therefore theoretically be explained by an acid pH in the cells. This seems improbable, however, and it is suggested that the phenomenon is due to the presence of unknown catechol derivatives. Analyses of the pH-dependent spectral changes indicate that the presumed catechol derivative in Tealia felina is β-hydroxylated, whereas that in Anemia salina is not.
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| 35. |
- Elofsson, Rolf
(författare)
-
Evolution of organ systems in the Crustacea: Mystacocarida and Cephalocrida in retrospect
- 2019
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Ingår i: Journal of Crustacean Biology. - : Oxford University Press (OUP). - 0278-0372 .- 1937-240X. ; 39:2, s. 91-97
-
Tidskriftsartikel (refereegranskat)abstract
- The morphology of the internal organs of two representative species of the crustacean classes Mystacocarida, Derocheilocaris typica (Pennak & Zinn, 1943), and Cephalocarida, Hutchinsoniella macracantha (Sanders, 1955), has been studied ultrastructurally from 1990 onwards. A review of the subject offers a unique opportunity to compare and contrast the two taxa at a time when their key positions in discussions of crustacean relationships and evolution makes any new knowledge particularly valuable. The same internal organ or organ system can be constructed very differently in the two groups, but similarities also occur. Both the similarities and differences suggest functional interpretations and shed light on evolutionary pathways. The importance of including anatomy and functional morphology in phylogenetic discussions is emphasized.
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| 36. |
- Elofsson, Rolf, et al.
(författare)
-
Evolutionary aspects on the construction of the first optic neuropil (lamina) in Crustacea
- 1986
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Ingår i: Zoomorphology. - 0720-213X. ; 106, s. 174-178
-
Tidskriftsartikel (refereegranskat)abstract
- A Golgi study of the neuronal morphology of the first optic neuropil (lamina) in three anostracan species revealed a close similarity in the lamina construction and neuron types. The lamina architecture of decapod and mysid crustacean species, as revealed by the Golgi method, conformed to previous studies and differed from the anostracans. The comparison was made at the level of resolution comprising retinal projection on the lamina, structural entities such as columns and layers and neuron position, branching pattern and terminal fields. It was shown that different types of compound eyes and variation in the habitat of the animals were of less importance for the lamina design than common descent as expressed in the present taxonomic groups.
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| 37. |
- Elofsson, Rolf, et al.
(författare)
-
Gland cells in the tentacles of the jellyfish Cyanea lamarcki reactive with an antibody against 5-hydroxytryptamine.
- 1989
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Ingår i: Cell and Tissue Research. - 1432-0878. ; 255, s. 419-422
-
Tidskriftsartikel (refereegranskat)abstract
- A light- and electron-microscopic immunocytochemical study on the localization of 5-hydroxytryptamine in Cyanea lamarcki revealed a reaction product in the epidermal gland cells surrounding the nematocyst clusters. The closely related scyphozoan medusa Cyanea capillata lacked a reaction product in the similar mucus-producing gland cells. Earlier conflicting views on the presence and localization of 5-hydroxytryptamine in coelenterates can thus be due to large species differences. It can be stated that 5-hydroxytryptamine is lacking in the venom of Cyanea.
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| 38. |
- Elofsson, Rolf, et al.
(författare)
-
Identification and quantitative measurements of biogenic amines and Dopa in the central nervous system and haemolymph of the crayfish Pacifastacus leniusculus (Crustacea)
- 1982
-
Ingår i: Comparative Biochemistry and Physiology. Part C: Comparative Pharmacology & Toxicology. - 0742-8413. ; 71, s. 195-201
-
Tidskriftsartikel (refereegranskat)abstract
- 1. The biogenic amines dopamine (DA), noradrenaline (NA), octopamine (OA), serotonin (5-HT) and the amino acid dihydroxyphenylalanine (DOPA) have been identified and quantitatively measured in the crayfish nervous system and in haemolymph employing high performance liquid chromatography (HPLC).2. The substances occurred in the nervous system in amounts ranging between 0.1 and 0.7 μg/g w/w.3. The haemolymph contained very small amounts of NA, OA, 5-HT and DOPA.4. No adrenaline (A) was present.5. Prolonged handling of the animals caused dramatic changes in DOPA levels.6. Depletion experiments using reserpine caused a pronounced decrease in the content of DA, NA, OA and 5-HT in the nervous system. DOPA, however, remained unaffected.
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| 39. |
- Elofsson, Rolf, et al.
(författare)
-
Is nitric oxide (NO) produced by invertebrate neurons?
- 1993
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Ingår i: NeuroReport. - 1473-558X. ; 4, s. 279-282
-
Tidskriftsartikel (refereegranskat)abstract
- NADPH-DIAPHORASE (NADPHd) is known to be identical to nitric oxide (NO) synthase in the mammalian nervous system, and is therefore used as a marker of NO-producing neurones. Using the histochemical reaction for NADPHd, we searched for such neurones in a selection of invertebrates. Special emphasis was given to molluscs. No selective neuronal staining was found in representatives of coelenterates, turbellarians, nematodes and urochordates. In all annelids, arthropods and molluscs examined, with the exception of a chiton, specific neurones were selectively stained. The reaction was particularly strong in pulmonate molluscs where scattered positive neurones were found in various ganglia and clustered symmetrically in the paired buccal ganglia. Biochemical assay of NO synthase in osphradia of the gastropod mollusc Lymnaea stagnalis revealed a formation of citrullin that was inhibited by the specific NO synthase N[omega]-nitro-L-arginine (NO2Arg). Both histochemical and biochemical methods indicate that NO can be used as a signal molecule by specific neurones in advanced invertebrates.
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| 40. |
- Elofsson, Rolf, et al.
(författare)
-
Localization of monoaminergic neurons in the central nervous system of Astacus astacus Linne (Crustacea, Decapoda)
- 1966
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Ingår i: Zeitschrift für Zellforschung und mikroskopische Anatomie. ; 74, s. 464-473
-
Tidskriftsartikel (refereegranskat)abstract
- The cellular localization of biogenic monoamines in crustaceans was studied by means of a highly specific and sensitive fluorescence method devised by Falck and Hillarp. It was found that neurons displaying specific fluorescence in the central nervous system were confined to the protocerebrum, the medulla externa and interna and the ventral nerve cord. The method allows a distinction between the fluorophores of 5-hydroxytryptamine (and 5-hydroxytryptophan), which emit the yellow light, and the fluorophores deriving from the catecholamines (and DOPA), which emit the green light. Green-fluorescent neurons occurred abundantly in the aforementioned parts of the central nervous system while yellow-fluorescent neurons were sparsely present in the same parts.
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| 41. |
- Elofsson, Rolf, et al.
(författare)
-
Monoamine-containing neurons in the optic ganglia of crustaceans and insects
- 1972
-
Ingår i: Zeitschrift für Zellforschung und mikroskopische Anatomie. ; 133, s. 475-499
-
Tidskriftsartikel (refereegranskat)abstract
- With the fluorescence method of Falck and Hillarp, the presence and localization of monoaminergic neurons in the optic ganglia of several crustaceans and insects have been investigated. It was found that in both classes the monoaminergic terminals, when present, appeared (especially in the medullae externa and interna of the crustaceans and the medulla of the insects) in strata specific for each species. So far, the only monoamine (visualized by this technique) present in the crustacean optic ganglia is dopamine, whereas in the Insecta, the catecholamines dopamine and noradrenaline, and the indolamine, 5-hydroxytryptamine, are found in the optic lobe. But in the Insecta, different species show different content of these amines.
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| 42. |
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| 43. |
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| 44. |
- Elofsson, Rolf, et al.
(författare)
-
On the cavity receptor organ (X-organ or organ of Bellonci) of Artemia salina (Crustacea, Anostraca)
- 1971
-
Ingår i: Zeitschrift für Zellforschung und mikroskopische Anatomie. ; 121, s. 319-326
-
Tidskriftsartikel (refereegranskat)abstract
- The cavity receptor organ (previously X-organ or organ of Bellonci) of Artemia salina consists of ciliated neurons whose cilia protrude into a cavity beneath the cuticle. The neuronal dendrites penetrate a giant accompanying cell and epidermal cells before entering the cavity. The cavity beneath the cuticle, the ciliated neurons and the connexion with the medulla terminalis justifies a homologization with the frontal filament organ of cirripeds and the third unit of copepods. The term cavity receptor is suggested for this organ. It is hardly homologous with the second unit of copepods and the organs described for many malacostracans under the names of sensory pore X-organ or organ of Bellonci. The latter organs are very similar to the cavity receptor but have an internal cavity formed by glial cells.The cavity receptor organ was previously considered neurosecretory but in the light of the present knowledge it is rather sensory although a double function cannot be denied.
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| 45. |
- Elofsson, Rolf
(författare)
-
Rhabdom adaptation and its phylogenetic significance
- 1976
-
Ingår i: Zoologica Scripta. - : Wiley. - 0300-3256 .- 1463-6409. ; 5, s. 97-101
-
Tidskriftsartikel (refereegranskat)abstract
- Rhabdom adaptation and its phylogenetic significance. Zool. Scr. 5 (3–4): 97–101, 1976. — The rhabdoms of arthropod compound eyes are structurally differentiated into open, fused layered, and fused continuous. All are capable of perceiving polarized light. The fused layered, and under certain conditions the fused continuous, perform particularly well. — The fused layered rhabdoms occur in malacostracan crustaceans and in various insect groups. This, together with, among other things, the presence of open rhabdoms in insects and crustaceans, indicates convergent development of organs and parts of organs. — Elaborate visual organs of more than one kind occur in crustaceans, as is exemplified by the compound and nauplius eyes. This shows that more than one construction on the organ level is possible in a restricted taxo-nomical unit for the. perception of light. The different rhabdom types performing well in receiving polarized light also show parallel evolution on a level below the organ. — The result of adaptation analyses indicates the need for a restricted use of the concept of homology basic to morphological investigations and a base for phylogenetic speculations. It also envisages a fruitful approach to a peep into the workshop of evolution. — It is concluded that a fully formed compound eye in arthropod ancestors is hardly conceivable. A realistic alternative is an inherent capacity of forming a compound eye. Thus the ancestral compound eye could have ranged from nothing to a partly-developed stage. The recent eyes need not originate from one source.
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| 46. |
- Elofsson, Rolf
(författare)
-
Sensory morphology in the antennae of the cephalocarid Hutchinsoniella macracantha (Crustacea)
- 1991
-
Ingår i: Journal of Crustacean Biology. - 0278-0372. ; 11, s. 345-355
-
Tidskriftsartikel (refereegranskat)abstract
- The first antenna of Hutchinsoniella macracantha is a 6-segmented, uniramous appendage carrying 1 aesthetasc and 22 setae (or sensilla). The second antenna is biramous and has approximately 80 setae. The sensory cells of the first antenna are arranged in 3 clusters in the first and second segments; one cluster serving the aesthetasc (approximately 130 cells), one the 11 setae of the sixth segment (approximately 100), and one the remaining setae (approximately 80). The sensory cells of the second antenna are distributed in a medial band along the length of the antenna. The sensory cells of the aesthetasc have 1 cilium each which splits into many branches. The sensory cells of the setae have 1 unbranched cilium each, and the number of sensory cells varies for each seta. The aesthetasc is a presumed olfactory organ, and all setae display features suggesting chemoreception. The aesthetasc combines malacostracan and nonmalacostracan features, whereas the setae conform to a general crustacean pattern.
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| 47. |
- Elofsson, Rolf, et al.
(författare)
-
Sensory structures associated with the cuticle of Hutchinsoniella macracantha (Crustacea, Cephalocarida)
- 1994
-
Ingår i: Journal of Crustacean Biology. - 0278-0372. ; 14, s. 454-462
-
Tidskriftsartikel (refereegranskat)abstract
- The body cuticle of the cephalocarid crustacean Hutchinsoniella macracantha Sanders, 1955, carries two types of small setae which differ in their external shape and number of ciliated sensory cells. It also has two types of pores, one being a gland opening, the other containing the tip of a cilium. The setae and the pore type containing a ciliated sensory cell are considered chemosensory organs.
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| 48. |
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| 49. |
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| 50. |
- Elofsson, Rolf
(författare)
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Some observations on the internal morphology of Hansen's nauplius Y (Crustacea)
- 1971
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Ingår i: Sarsia. - : Informa UK Limited. - 0036-4827. ; 46, s. 23-40
-
Tidskriftsartikel (refereegranskat)abstract
- The internal morphology of the crustacean larval form that Hansen (1899) called nauplius y has revealed a remarkably advanced early nauplius. The nervous system is well developed and differentiated. It is connected with the anlagen of the compound eyes. A presumed filamentous base of the SPX-organ connects with these. The nauplius eye is present in a three-partite form with two retinula cells in each cup. The alimentary canal consists of the ectodermal oesophagus with an inner layer of longitudinal muscles and an outer circular layer, and of the endodermal midgut with cells having microvillous borders against the lumen. There is no proctodeum or anus present. There is a well-developed muscular system. The head contains a large gland with a paired ventral outlet. A new dorsocaudal organ of doubtful function is described.The morphological facts presented in this investigation indicate that the nauplius y, as knowledge stands today, is close to the Cirripedia.
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