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| 2. |
- Dircksen, Heinrich, 1954-, et al.
(author)
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Crustacean cardioactive peptide in the nervous system of the locust, Locusta migratoria: an immunocytochemical study on the ventral nerve cord and peripheral innervation
- 1991
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In: Cell and Tissue Research. - Heidelberg New York : Springer. - 0302-766X .- 1432-0878. ; 263, s. 439-457
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Journal article (peer-reviewed)abstract
- Crustacean cardioactive peptide-immunoreactive neurons occur in the entire central nervous system of Locusta migratoria. The present paper focuses on mapping studies in the ventral nerve cord and on peripheral projection sites. Two types of contralaterally projecting neurons occur in all neuromers from the subesophageal to the seventh abdominal ganglia. One type forms terminals at the surface of the thoracic nerves 6 and 1, the distal perisympathetic organs, the lateral heart nerves, and on ventral and dorsal diaphragm muscles. Two large neurons in the anterior part and several neurons of a different type in the posterior part of the terminal ganglion project into the last tergal nerves. In the abdominal neuromers 1–7, two types of ipsilaterally projecting neurons occur, one of which gives rise to neurosecretory terminals in the distal perisympathetic organs, in peripheral areas of the transverse, stigmata and lateral heart nerves. Four subesophageal neurons have putative terminals in the neurilemma of the nervus corporis allati II, and in the corpora allata and cardiaca. In addition, several immunoreactive putative interneurons and other neurons were mapped in the ventral nerve cord. A new in situ whole-mount technique was essential for elucidation of the peripheral pathways and targets of the identified neurons, which suggest a role of the peptide in the control of heartbeat, abdominal ventilatory and visceral muscle activity.
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| 3. |
- Dircksen, Heinrich, 1954-, et al.
(author)
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Immunocytochemical demonstration of the neurosecretory systems containing putative moult-inhibiting hormone and hyperglycemic hormone in the eyestalk of brachyuran crustaceans
- 1988
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In: Cell and Tissue Research. - 0302-766X .- 1432-0878. ; 251, s. 3-12
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Journal article (peer-reviewed)abstract
- By use of antisera raised against purified moultinhibiting (MIH) and crustacean hyperglycemic hormone (CHH) from Carcinus maenas, complete and distinct neurosecretory pathways for both hormones were demonstrated with the PAP and immunofluorescence technique. By double staining, employing a combination of silver-enhanced immunogold labelling and PAP, both antigens could be visualized in the same section. Immunoreactive structures were studied in Carcinus maenas, Liocarcinus puber, Cancer pagurus, Uca pugilator and Maja squinado. They were only observed in the X-organ sinus gland (SG) system of the eyestalks and consisted of MIH-positive perikarya, which were dispersed among the more numerous CHH-positive perikarya of the medulla terminalis X-organ (XO). The MIH-positive neurons form branching collateral plexuses adjacent to the XO and axons that are arranged around the CHH-positive central axon bundle of the principal XO-SG tract. In the SG, MIH-positive axon profiles and terminals, clustered around hemolymph lacunae, are distributed between the more abundant CHH-positive axon profiles and terminals. Colocalisation of MIH and CHH was never observed. The gross morphology of both neurosecretory systems was similar in all species examined, however, in U. pugilator and M. squinado immunostaining for MIH was relatively faint unless higher concentrations of antiserum were used. Possible reasons for this phenomenon as well as observed moult cycle-related differences in immunostaining are discussed.
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| 4. |
- Dircksen, Heinrich, 1954-, et al.
(author)
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Immunocytochemical localization of CCAP, a novel crustacean cardioactive peptide, in the nervous system of the shore crab, Carcinus maenas L.
- 1988
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In: Cell and Tissue Research. - 0302-766X .- 1432-0878. ; 254:2, s. 347-360
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Journal article (peer-reviewed)abstract
- Polyclonal antibodies were raised in rabbits against synthetic crustacean cardioactive peptide (CCAP) conjugated to bovine thyroglobulin, and were used to map CCAP-immunoreactive structures in the central nervous system of Carcinus maenas. As expected, the neurohemal pericardial organs (PO) displayed abundant immunoreactivity in nerve fibers and terminals. In addition, immunoreactive neurons were demonstrated in other parts of the nervous system. At least some of them do not appear to terminate in neurohemal structures and may have a non-endocrine, as yet unknown function. Immunoreactive perikarya with a diameter of 25–30 m occur in the brain. They project into the optic and antennary neuropil, and into the eyestalk. One cell was found in the medulla terminalis of the eyestalk and in the connective ganglion, respectively. From the latter, axonal branches could be traced into the brain and the thoracic ganglia (TG). In the TG, small-diameter perikarya give rise to extensive networks of varicose fibers. Some of the perikarya occur in a characteristic paired arrangement with larger CCAP-immunoreactive somata (diameter 40–50 m). These pairs of one small and one large cell occur in all mouthpart and leg segments of the TG, except the abdominal ganglia (AG), where only large cells were found. The main projections of the large neurons comprise one or more fibers in each of the seven segmental nerves (SN), leading to neurosecretory terminals in the PO. The fibers in the SN are joined by branches of an ascending axonal tract from the large perikarya in the AG. The large-type perikarya are considered to be the principal source of CCAP in the PO. The optic ganglia in the eyestalk, except the medulla terminalis, the neurohemal sinus gland and the stomatogastric nervous system are devoid of CCAP-immunoreactivity.In axon terminals of the PO, CCAP is not colocalized with other PO-neuropeptides, i.e. proctolin-, FMRFamide-like, and Leu-enkephalin-like immunoreactive materials. Electron-microscopic immunocytochemistry revealed a distinct CCAP-containing granule type in specific axon profiles and terminals in the PO.The architecture of CCAP-immunoreactive neurons is discussed with respect to previous morphological studies on the origin and pathways of fibers terminating in the PO.
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| 5. |
- Dircksen, Heinrich, 1954-, et al.
(author)
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The ultrastructure of nerve endings containing pigment-dispersing hormone (PDH) in crustacean sinus glands: Identification by an antiserum against a synthetic PDH
- 1987
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In: Cell and Tissue Research. - : Springer. - 0302-766X .- 1432-0878. ; 250:2, s. 377-387
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Journal article (peer-reviewed)abstract
- A high-liter antiserum has been obtained from two rabbits immunized with a glutaraldehyde conjugate of synthetic pigment-dispersing hormone (PDH) from Uca pugilator and bovine thyroglobulin. The antiserum blocked melanophore-dispersing activity of the peptide in vivo. In sinus glands (SG) of Carcinus maenas, Cancer pagurus, Uca pugilator and Orconectes limosus, electron-microscopic immunocytochemistry revealed sparsely distributed axon endings containing a distinct PDH-immunoreactive type of neurosecretory granules (diameter 90–130 nm). Exocytotic figures indicating release of the content of these granules into hemolymph lacunae were occasionally observed. Preservation of fine structure and antigenicity of the PDH granules were markedly dependent on the fixation procedure used. A preliminary experiment with C. maenas showed that preterminal axon dilatations near the basal lamina seemed to accumulate PDH-granules when animals were kept in complete darkness for three days. Immunodot blotting of fractions after high pressure liquid chromatography (HPLC) of extracts from SGs of C. maenas and O. limosus revealed a strongly immunoreactive substance at a retention time very similar to those of synthetic PDHs of Uca pugilator and Pandalus borealis. It is also coincident with a zone of biological activity. Thus, the antigen demonstrated by immunocytochemistry is identical or very similar to one of the known PDHs.
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| 6. |
- Gattinger, Pia, et al.
(author)
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Neutralization of SARS-CoV-2 requires antibodies against conformational receptor-binding domain epitopes
- 2022
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In: Allergy. European Journal of Allergy and Clinical Immunology. - : Wiley. - 0105-4538 .- 1398-9995. ; 77:1, s. 230-242
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Journal article (peer-reviewed)abstract
- Background: The determinants of successful humoral immune response to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are of critical importance for the design of effective vaccines and the evaluation of the degree of protective immunity conferred by exposure to the virus. As novel variants emerge, understanding their likelihood of suppression by population antibody repertoires has become increasingly important.Methods: In this study, we analyzed the SARS-CoV-2 polyclonal antibody response in a large population of clinically well-characterized patients after mild and severe COVID-19 using a panel of microarrayed structurally folded and unfolded SARS-CoV-2 proteins, as well as sequential peptides, spanning the surface spike protein (S) and the receptor-binding domain (RBD) of the virus.Results: S- and RBD-specific antibody responses were dominated by immunoglobulin G (IgG), mainly IgG1, and directed against structurally folded S and RBD and three distinct peptide epitopes in S2. The virus neutralization activity of patients´ sera was highly correlated with IgG antibodies specific for conformational but not sequential RBD epitopes and their ability to prevent RBD binding to its human receptor angiotensin-converting enzyme 2 (ACE2). Twenty percent of patients selectively lacked RBD-specific IgG. Only immunization with folded, but not with unfolded RBD, induced antibodies against conformational epitopes with high virus-neutralizing activity. Conformational RBD epitopes required for protection do not seem to be altered in the currently emerging virus variants.Conclusion: These results are fundamental for estimating the protective activity of antibody responses after natural infection or vaccination and for the design of vaccines, which can induce high levels of SARS-CoV-2–neutralizing antibodies conferring sterilizing immunity.
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| 7. |
- Jaros, Peter P., et al.
(author)
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Occurrence of immunoreactive enkephalins in a neurohemal organ and other nervous structures in the eyestalk of the shore crab, Carcinus maenas L. (Crustacea, Decapoda)
- 1985
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In: Cell and Tissue Research. - 0302-766X .- 1432-0878. ; 241:1, s. 111-117
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Journal article (peer-reviewed)abstract
- Light-microscopical observations with immunofluorescence and peroxidase staining procedures revealed leu-enkephalin-like immunoreactivity in axon profiles of the sinus gland (SG) and in single small neurons in the optic ganglia of the eyestalk of Carcinus maenas. Electron microscopy of the SG showed reactivity to be associated with neurosecretory granules 82±23 nm in diameter. High performance liquid chromatography of SG-extracts revealed radioimmunoreactive substances with the retention times of synthetic met- and leu-enkephalin and met-enkephalin-Arg6-Phe7, respectively.
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| 8. |
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| 9. |
- Lai, Ian-Lin, et al.
(author)
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Gas outflow and dust transport of comet 67P/Churyumov-Gerasimenko
- 2016
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In: Monthly notices of the Royal Astronomical Society. - : OXFORD UNIV PRESS. - 0035-8711 .- 1365-2966. ; 462, s. S533-S546
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Journal article (peer-reviewed)abstract
- Because of the diurnal thermal cycle and the irregular shape of the nucleus, gas outflow of comet 67P/Churyumov-Gerasimenko could be highly anisotropic as indicated by the colliminated dust jet structures on the sunlit side. Based on the OSIRIS imaging observations of the outgassing effect, a simple model of surface sublimation can be constructed by taking into account the dependence on the solar insolation. With preliminary information on the time variability of the global gas production rate, a sequence of gas coma models can be generated at different epochs before and after perihelion. We also investigate different patterns of dust particle dynamics under the influences of nuclear rotation and gas drag. From these considerations, a consistent picture of the spatial distribution of dusty materials across the surface of comet 67P as it moves around the perihelion can be developed. It is found that because of the redeposition of the ejected dust from the Southern hemisphere to the Northern hemisphere during the southern summer season the Hapi region could gain up to 0.4 m while the Wosret region would lose up to 1.8 m of dust mantle per orbit.
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| 10. |
- Lee, Jui-Chi, et al.
(author)
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Geomorphological mapping of comet 67P/Churyumov-Gerasimenko's Southern hemisphere
- 2016
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In: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 462, s. S573-S592
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Journal article (peer-reviewed)abstract
- In 2015 May, the Southern hemisphere of comet 67P/Churyumov-Gerasimenko became visible by the OSIRIS cameras on-board the Rosetta spacecraft. The resolution was high enough to carry out a detailed analysis of the surface morphology, which is quite different from the Northern hemisphere. Previous works show that fine particle deposits are the most extensive geological unit in the Northern hemisphere. In contrast, the Southern hemisphere is dominated by outcropping consolidated terrain. In this work, we provide geomorphological maps of the Southern hemisphere with the distinction of both geological units and linear features. The geomorphological maps described in this study allow us to gain a better understanding of the processes shaping the comet nucleus and the distribution of primary structures such as fractures and strata.
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