TY - THES A1 - Nguyen, Manh Duy Linh T1 - Reproduction, development and reproductive isolation barriers of the mormyrid fish (genus Campylomormyrus, Teleostei) T1 - Fortpflanzung, Entwicklung und reproduktive Isolationsbarrieren von Mormyriden (Gattung Campylomormyrus, Teleostei) N2 - Weakly electric mormyrid fish comprise about 200 species. 15 species of the genus Campylomormyrus have been described. These are very diverse concerning the trunk-like snout and the shape and duration of the electric organ discharge (EOD) and the anatomy of the electric organ. In this dissertation data on the reproduction in captivity of four species and on the ontogeny of the EOD and the EO of three species are presented. Reproduction of the four species C. compressirostris, C. rhynchophorus, C. tshokwe and C. numenius: Cyclical reproduction was provoked by changing only water conductivity (C): decreasing C led to gonadal recrudescence, an increase induced gonad regression. Data on the reproduction and development of three species are presented (in C. numenius gonad development could only be achieved in males). Agonistic behavior in the C. tshokwe pair forced us to divide the breeding tank; therefore, only ovipositions occurred. However, injection of an artificial GnRH hormone allowed us to obtain ripe eggs and sperm and to perform successful artificial reproduction. All three species (C. compressirostris, C. rhynchophorus, C. tshokwe) are indeterminate fractional spawners. Spawnings/ovipositions occurred during the second half of the night; no parental care was observed; no special spawning substrates were necessary. C. compressirostris successfully spawned in breeding groups, C. rhynchophorus as pair. Spawning intervals ranged from 6 to 66 days in C. rhynchophorus, 10–75 days in C. tshokwe, and 18 days in C. compressirostris (calculated values). Fecundities (eggs per fractional spawning) ranged from 70 to 1570 eggs in C. rhynchophorus, 100–1192 in C. tshokwe, and 38–246 in C. compressirostris. All three species produce yolky, slightly sticky eggs. Egg diameter ranges from 2.3–3.0 mm. Hatching occurred on day 3, feeding started on day 11. Transition from larval to juvenile stage occurred at around 20 mm total length (TL). At this size C. rhynchophorus developed a higher body than the two other species and differences between the species in the melanin pigmentation of the unpaired fins occurred. Between 32 and 35 mm TL the upper and lower jaws developed. C. compressirostris and C. tamandua are similar in morphology and both produce short EODs of ca. 150-200 μs duration. Both species reproduce easily in captivity. We tried to obtain natural hybrids in two breeding groups, 1) four males of C. compressirostris and three females of C. tamandua and 2) six females of C. compressirostris and four males of C. tamandua. In both combinations several times oviposition occurred, however, we never found fertilized eggs. In subsequent experiments, not described here, we obtained hybrids between these two species by means of artificial reproduction. Ontogeny of the EOD and the EO: The Campylomormyrus species are very diverse both concerning the shape and the duration of their EODs. There are species with very short EODs, e.g. C. compressirostris duration, a species with an EOD length of about 4-8 ms duration (C. tshokwe) and species with very long EODs of about 25 ms duration (e.g. C. rhynchophorus). Due to the successful breeding of the three species in captivity, we were able to investigate in detail the ontogeny of the EOD. Larvae of the three species C. compressirostris, C. tshokwe and C. rhynchophorus first produce a biphasic larval EOD typical for these small larvae. The first activity of the adult electric organ in the caudal peduncle is a biphasic juvenile EOD. Juvenile C. compressirostris and C. tshokwe start out with a short biphasic EOD of about 160 – 200 μs duration at sizes between 25 mm (C. compressirostris) and 37 mm (C. tshokwe). Adult C. compressirostris show an EOD identical to that of the juvenile. In C. tshokwe, the juvenile EOD changes continuously during development both concerning duration, amplitude increase and shape. 18 cm long C. tshokwe still do not yet produce an EOD typical for the adult fish. Juveniles of C. rhynchophorus produce at 33 mm total length a juvenile biphasic EOD, however, of longer duration (about 640 μs) than the two species mentioned above. This juvenile EOD changes continuously both in form, amplitude increase and duration with growth until the adult EOD waveform appears at about 15 cm body length. In juveniles about seven cm long the triphasic feature of the EOD starts to develop due to the appearance of a second head positive phase. Specific EOD stages are produced in relation to size and not to age. Individual differences in the EOD both concerning shape and duration are very small. The basic anatomy of the electrocytes is very similar in all three species: the main stalk which receives the innervation, is located at the caudal face of the electrocyte. Membrane penetrations of the stalks do not occur. However, there are differences in the fine structure of the electrocytes in the three species. Papillae, proliferations of the membrane, which increase the surface area of the electrocyte and are thought to incrase the EOD-duration, are only found in C. tshokwe and C. rhynchophorus. In these two species in addition, holes develop in the electrocytes during ontogeny. This might also have an impact on EOD duration. N2 - Von den mehr als 200 Arten der schwach elektrischen Nilhechte gehören 15 zur Gattung Campylomormyrus. Diese spezialisierten Fische besitzen eine rüsselartige Schnauze. Auch produzieren manche Arten relativ kurze elektrische Entladungen (EODs) von mehreren hundert µs Dauer, andere ungewöhnlich lange EODs von bis zu 25 ms Dauer. Es werden Daten zur Reproduktion von vier Arten vorgestellt, um das Wissen über die Fortpflanzungs-biologie der Nilhechte zu erweitern und zum ersten Mal detaillierte Daten zur Ontogenese der elektrischen Organe (EO) und EODs von Arten mit extrem langen EODs zu beschreiben. Bei C. compressirostris, C. rhynchophorus, C. tshokwe und C. numenius konnte die Gonadenreifung durch Absenkung der elektrischen Leitfähigkeit des Wassers ausgelöst werden. Danach laichten C. compressirostris und C. rhynchophorus regelmäßig ab; bei C. tshokwe konnte eine Vermehrung mit Hilfe einer künstlichen Vermehrung erreicht werden; bei C. numenius konnte nur bei den Männchen eine Gonadenreifung ausgelöst werden. Die drei Arten C. compressirostris, C. rhynchophorus und C. tshokwe zeigen folgende reproduktiven Merkmale: das Ablaichen erfolgt in der zweiten Nachthälfte, die Eizahlen liegen bei mehreren Hundert pro Ablaichen, die Ablaichintervalle liegen bei wenigen Wochen. Embryonen schlüpfen nach drei Tagen, die exogene Nahrungsaufnahme beginnt am Tag 11. Es wurde versucht, natürliche Hybriden zwischen den Arten C. compressirostris und C. tamandua zu erhalten. Es kam zwar zur Abgabe von Eiern, diese waren aber nie befruchtet. Die Ontogenese der EOD zeigte, dass die Entladung bei allen drei untersuchten Arten mit einer biphasischen Juvenilentladung von ca. 200 µs (C. compressirostris, C. tshokwe) bzw. ca. 600 µs Dauer (C. rhynchophorus) beginnt. Diese Entladung verändert sich im Verlauf der Ontogenese bei C. compressirostris nicht mehr, bei den beiden anderen Arten kommt es zu einer kontinuierlichen Veränderung bezüglich Form und Dauer bis hin zu der Adult-Entladung. Papillen, Oberflächenvergrößerungen der elektrischen Zellen, könnten eine Erklärung für die längere Entladung bei C. tshokwe und C. rhynchophorus sein. KW - fish KW - weakly electric fish KW - tropical freshwater fish KW - Fisch KW - schwach elektrische Fische KW - tropische Süßwasser Fische Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-437197 ER - TY - JOUR A1 - Korniienko, Yevheniia A1 - Nguyen, Linh A1 - Baumgartner, Stephanie A1 - Vater, Marianne A1 - Tiedemann, Ralph A1 - Kirschbaum, Frank T1 - Correction to: Intragenus F1-hybrids of African weakly electric fish (Mormyridae: Campylomormyrus tamandua male x C. compressirostris female) are fertile (vol 206, pg 571, 2020) JF - Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology Y1 - 2021 U6 - https://doi.org/10.1007/s00359-021-01513-2 SN - 0340-7594 SN - 1432-1351 VL - 207 IS - 6 SP - 773 EP - 773 PB - Springer CY - Heidelberg ER - TY - GEN A1 - Wolff, Christian Michael A1 - Canil, Laura A1 - Rehermann, Carolin A1 - Nguyen, Ngoc Linh A1 - Zu, Fengshuo A1 - Ralaiarisoa, Maryline A1 - Caprioglio, Pietro A1 - Fiedler, Lukas A1 - Stolterfoht, Martin A1 - Kogikoski, Junior, Sergio A1 - Bald, Ilko A1 - Koch, Norbert A1 - Unger, Eva L. A1 - Dittrich, Thomas A1 - Abate, Antonio A1 - Neher, Dieter T1 - Correction to 'Perfluorinated self-assembled monolayers enhance the stability and efficiency of inverted perovskite solar cells' (2020, 14 (2), 1445−1456) T2 - ACS nano Y1 - 2020 U6 - https://doi.org/10.1021/acsnano.0c08081 SN - 1936-0851 SN - 1936-086X VL - 14 IS - 11 SP - 16156 EP - 16156 PB - American Chemical Society CY - Washington, DC ER - TY - JOUR A1 - Nguyen, Manh Duy Linh A1 - Mamonekene, Victor A1 - Vater, Marianne A1 - Bartsch, Peter A1 - Tiedemann, Ralph A1 - Kirschbaum, Frank T1 - Ontogeny of electric organ and electric organ discharge in Campylomormyrus rhynchophorus (Teleostei: Mormyridae) JF - Journal of comparative physiology; A, Neuroethology, sensory, neural, and behavioral physiology N2 - The aim of this study was a longitudinal description of the ontogeny of the adult electric organ of Campylomormyrus rhynchophorus which produces as adult an electric organ discharge of very long duration (ca. 25 ms). We could indeed show (for the first time in a mormyrid fish) that the electric organ discharge which is first produced early during ontogeny in 33-mm-long juveniles is much shorter in duration and has a different shape than the electric organ discharge in 15-cm-long adults. The change from this juvenile electric organ discharges into the adult electric organ discharge takes at least a year. The increase in electric organ discharge duration could be causally linked to the development of surface evaginations, papillae, at the rostral face of the electrocyte which are recognizable for the first time in 65-mm-long juveniles and are most prominent at the periphery of the electrocyte. KW - Weakly electric fish KW - Development KW - Electric organ discharge KW - Electric KW - organ KW - Electrocyte features Y1 - 2020 U6 - https://doi.org/10.1007/s00359-020-01411-z SN - 0340-7594 SN - 1432-1351 VL - 206 IS - 3 SP - 453 EP - 466 PB - Springer CY - Berlin ; Heidelberg ER - TY - JOUR A1 - Korniienko, Yevheniia A1 - Nguyen, Linh A1 - Baumgartner, Stephanie A1 - Vater, Marianne A1 - Tiedemann, Ralph A1 - Kirschbaum, Frank T1 - Intragenus F1-hybrids of African weakly electric fish (Mormyridae: Campylomormyrus tamandua male x C. compressirostris female) are fertile JF - Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology N2 - Hybridization is widespread in fish and constitutes an important mechanism in fish speciation. There is, however, little knowledge about hybridization in mormyrids. F1-interspecies hybrids betweenCampylomormyrus tamandua male x C. compressirostris female were investigated concerning: (1) fertility; (2) survival of F2-fish and (3) new gene combinations in the F2-generation concerning the structure of the electric organ and features of the electric organ discharge. These F1-hybrids achieved sexual maturity at about 12-13.5 cm total length. A breeding group comprising six males and 13 females spawned 28 times naturally proving these F1-fish to be fertile. On average 228 eggs were spawned, the average fertilization rate was 47.8%. Eggs started to hatch 70-72 h after fertilization, average hatching rate was 95.6%. Average mortality rate during embryonic development amounted to 2.3%. Average malformation rate during the free embryonic stage was 27.7%. Exogenous feeding started on day 11. In total, we raised 353 normally developed larvae all of which died consecutively, the oldest specimen reaching an age of 5 months. During survival, the activities of the larval and adult electric organs were recorded and the structure of the adult electric organ was investigated histologically. KW - mormyridae KW - campylomormyrus KW - F1-hybrids KW - F2-hybrids KW - fertility Y1 - 2020 U6 - https://doi.org/10.1007/s00359-020-01425-7 SN - 0340-7594 SN - 1432-1351 VL - 206 IS - 4 SP - 571 EP - 585 PB - Springer CY - Heidelberg ER -