scholarly journals May the palps be with you – new insights into the evolutionary origin of anterior appendages in Terebelliformia (Annelida)

BMC Zoology ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Paul Kalke ◽  
Patrick Beckers ◽  
Conrad Helm
Keyword(s):  
Brain Region ◽  
Dorsal Root ◽  
Alimentary Canal ◽  
Morphological Changes ◽  
Morphological Diversity ◽  
Ventral Root ◽  
Evolutionary Origin ◽  
Serial Sections ◽  
The Past ◽  
Morphological Criteria

Abstract Background Head appendages in Annelida contribute significantly to the immense morphological diversity in this spiralian taxon. Nevertheless, the evolutionary origin of annelid antennae, palps, cirri and tentacles are part of vast theories and debates that took place over decades. One of these heavily discussed groups are the Terebelliformia, which bear numerous anterior tentacles originating from different regions of the head. The question, whether these tentacles are homologous to feeding palps in other annelids or if these structures evolved convergently in terebellids and the remaining taxa, has been highly debated in the past. Results By using morphological methods including immunohistochemistry, confocal microscopy, Azan-stained serial sections and 3D-visualisation, we are able to shed new light and a fresh look on the old question of the evolutionary origin of the buccal tentacles and their associated head structures in Terebelliformia. Our investigations show that the brains of the ampharetid Hypania invalida and the aulophora larvae of Lanice conchilega (Terebellidae) consist of a dorsal, more prominent and a more slender, ventral brain region. Neurite bundles innervating the buccal tentacles split off from the ventral and dorsal root within the ventral brain region and thus originate from the dorsal and ventral root of the circumoesophageal connectives. Hence, the observed neurite bundles fulfil the morphological criteria for the innervating neurite bundles of feeding palps known from Paleoannelida. Conclusions We disagree with former conclusions that buccal tentacles are part of the alimentary canal. Based on the presented data, the buccal tentacles of terebelliform taxa are innervated by neurite bundles and can be homologized with peristomial feeding palps of other Annelida. Our comparative investigations reveal important insights into morphological changes during the evolution of anterior head appendages in Terebelliformia and Annelida in general. Nevertheless, our analyses also illustrate the gaps in knowledge and that more investigations throughout the annelid tree are necessary to explain and understand the huge diversity of annelid anterior appendages.

scholarly journals May the Palps Be With You – New Insights Into the Evolutionary Origin of Anterior Appendages in Terebelliformia (Annelida)

2021 ◽  
Author(s):  
Paul Kalke ◽  
Patrick Beckers ◽  
Conrad Helm
Keyword(s):  
Brain Region ◽  
Dorsal Root ◽  
Alimentary Canal ◽  
Morphological Changes ◽  
Morphological Diversity ◽  
Ventral Root ◽  
Evolutionary Origin ◽  
Serial Sections ◽  
The Past ◽  
Morphological Criteria

Abstract Background: Head appendages in Annelida highly contribute to the immense morphological diversity in this lophotrochozoan taxon. Nevertheless, the evolutionary origin of annelid antennae, palps, cirri and tentacles are part of vast theories and debates that took place over decades. One of these heavily discussed groups are the Terebelliformia, which bear numerous anterior tentacles originating from different regions of the head. The question, whether these tentactes are homologous to feeding palps in other annelids or if these structures evolved convergently in terebellids and the remaining taxa, was highly debated in the past. Results: By using morphological methods including immunohistochemistry, confocal microscopy, Azan-stained serial sections and 3D-visualisation, we are able to shed new light and a fresh look on the old question of the evolutionary origin of the buccal tentacles and their associated head structures in Terebelliformia. Our investigations show that the brains of the ampharetid Hypania invalida and the aulophora larvae of Lanice conchilega (Terebellidae) consist of a dorsal, more prominent and a more slender, ventral brain region. Neurite bundles innervating the buccal tentacles split off from the ventral and dorsal root within the ventral brain region and thus originate from the dorsal and ventral root of the circumoesophageal connectives. Hence, the observed neurite bundles fulfil the morphological criteria for the innervating neurite bundles of feeding palps known from Paleoannelida.Conclusions: We disagree with former conclusions that buccal tentacles are part of the alimentary canal. Based on the presented data, the buccal tentacles of terebelliformian taxa can be homologized with feeding palps of other Annelida. Our comparative investigations reveal important insights into morphological changes during the evolution of anterior head appendages in Terebelliformia and Annelida in general. Nevertheless, our analyses also illustrate the gaps in knowledge and that more investigations throughout the annelid tree are necessary to explain and understand the huge diversity of annelid anterior appendages.

Membrane-associated microtubular areays induced in proximal myelinated processes of dorsal root ganglia by large doses of vitamin B6

1986 ◽  
Vol 44 ◽  
pp. 368-369
Author(s):  
V.J. Montpetit ◽  
S. Dancea ◽  
L. Tryphonas ◽  
D.F. Clapin
Keyword(s):  
Animal Model ◽  
Endoplasmic Reticulum ◽  
Dorsal Root Ganglia ◽  
Rough Endoplasmic Reticulum ◽  
Dorsal Root ◽  
Vitamin B6 ◽  
Morphological Changes ◽  
Model System ◽  
Sensory Nerves ◽  
Peripheral Sensory

Very large doses of pyridoxine (vitamin B6) are neurotoxic in humans, selectively affecting the peripheral sensory nerves. We have undertaken a study of the morphological and biochemical aspects of pyridoxine neurotoxicity in an animal model system. Early morphological changes in dorsal root ganglia (DRG) associated with pyridoxine megadoses include proliferation of neurofilaments, ribosomes, rough endoplasmic reticulum, and Golgi complexes. We present in this report evidence of the formation of unique aggregates of microtubules and membranes in the proximal processes of DRG which are induced by high levels of pyridoxine.

scholarly journals Split-footed lacewings declined over time: indications from the morphological diversity of their antlion-like larvae

PalZ ◽  
2021 ◽  
Author(s):  
Gideon T. Haug ◽  
Carolin Haug ◽  
Serita van der Wal ◽  
Patrick Müller ◽  
Joachim T. Haug
Keyword(s):  
Morphological Diversity ◽  
Single Specimen ◽  
Burmese Amber ◽  
The Past ◽  
The World ◽  
Poor Group ◽  
Outline Analysis ◽  
Loss Of Diversity ◽  
Over Time ◽  
Antlion Larvae

AbstractNymphidae, the group of split-footed lacewings, is a rather species-poor group. Split-footed lacewings nowadays are restricted to Australasia, while fossil forms are also known from other areas of the world, indicating that the group was more species-rich and therefore likely diverse in the past. Split-footed lacewings have rather distinct larvae, roughly resembling antlion larvae, but differing from the latter especially with regard to the mandibles. Antlion larvae usually have three prominent teeth on each mandible, while at least extant larvae of split-footed lacewings only have a single prominent tooth per mandible. Fossils interpreted as larvae of split-footed lacewings are well known from amber from Myanmar (ca. 100 myr; Burmese amber) and by a single specimen from Baltic amber (about 40 myr). We here report additional fossil specimens from Myanmar amber, expanding the known record of fossil forms from six depicted specimens to 15. For the extant fauna, we could compile 25 larvae. We compare the diversity of shape of extant and fossil larvae through time using an outline analysis (based on elliptic Fourier transformation) of the head. The results of this analysis indicate that the morphological diversity, or disparity, of split-footed lacewing larvae was higher in the past than it is today. With this type of analysis, we can show a loss of diversity over time, without the necessity to identify the fossil larvae down to a narrow taxonomical range. A similar pattern has already been recognised in silky lacewings, Psychopsidae. This might indicate a general loss of diversity of lacewing larvae.

scholarly journals Comparing skull formation of the Hungarian (Hortobágy) Zackel sheep breed by geometrics morphometrics

2015 ◽  
pp. 29-33
Author(s):  
Zsuzsanna Csóri ◽  
András Gáspárdy ◽  
András Jávor
Keyword(s):  
Morphological Changes ◽  
Time Change ◽  
Carpathian Basin ◽  
Sheep Breed ◽  
Geometric Morphometric ◽  
The Past ◽  
Morphometric Methods ◽  
Skull Formation ◽  
Over Time

This work seeks to explore the morphological changes of the Hungarian (Hortobágy) Zackel sheep's skull, which occurred in the past 50–70 years. In this study, we compared individuals skull forms by geometric morphometric methods. The origin of the breed is not known, we do not know when entering the Carpathian Basin. Therefore, the comparison involved the only known early archaeological findings. We have shown that there is no difference between each period colour variations, but over time change has occurred in the skull formation of the breed.

scholarly journals In Vitro Mutagenesis of Etlingera elatior by Gamma Ray Intermittent Irradiation

2018 ◽  
Vol 5 (3) ◽  
pp. 111-118 ◽  
Author(s):  
Elmi Irmayanti Azzahra ◽  
Syarifah Iis Aisyah ◽  
Diny Dinarti ◽  
Krisantini Krisantini
Keyword(s):  
Gamma Ray ◽  
Morphological Changes ◽  
Leaf Shape ◽  
Morphological Diversity ◽  
Mutation Breeding ◽  
Ornamental Plant ◽  
In Vitro Mutagenesis ◽  
Split Dose ◽  
Etlingera Elatior

Etlingera elatior is tropical ornamental plant commonly called “torch ginger” from Zingiberaceae family. Conventional breeding of E. elatior is limited by cross incompatibility, poor fruit set and low seed production.  In this study irradiation of E. elatior with Gamma ray performed to induce mutation. This study was aimed to increase morphological diversity and to obtain unique morphological characters to increase the aesthetic value of E. elatior as ornamental plants and cut flower. Two genotypes of E. elatior, red and white flowers, were tested. The LD20, LD35, and LD50 were determined following intermittent (split dose) Gamma irradiation with a two-hour gap between each gamma ray shot. Red genotype E. elatior explants were irradiated with dose of 3 + 3 Gy (LD20); 4 + 4 Gy (LD35) and 5 + 5 Gy (LD50); white genotype were irradiated with a dose of 2 + 2 Gy (LD20); 2.8 + 2.8 Gy (LD35) and 3.7 + 3.7 Gy (LD50). Non-irradiated explants were set as control.  The results of this study indicated that the increase in dose of gamma ray irradiation changed shoot length and number of leaves in the red genotype per explant as compared to control. Morphological changes occurred in leaf shape at 5 + 5 Gy and 3.7 + 3.7 Gy and formation of variegated leaves at 2.8 + 2.8 Gy and 5 + 5 Gy. Keywords: mutation breeding, ornamental plant, split irradiation dose, torch ginger, Zingiberaceae

scholarly journals Cation Doping Approach for Nanotubular Hydrosilicates Curvature Control and Related Applications

Crystals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 654
Author(s):  
Andrei A. Krasilin ◽  
Ekaterina K. Khrapova ◽  
Tatiana P. Maslennikova
Keyword(s):  
Crystal Structure ◽  
Chemical Composition ◽  
Morphological Changes ◽  
High Technology ◽  
Synthetic Approach ◽  
Cation Doping ◽  
The Past ◽  
Technology Applications ◽  
Curvature Control ◽  
Uptake And Release

The past two decades have been marked by an increased interest in the synthesis and the properties of geoinspired hydrosilicate nanoscrolls and nanotubes. The present review considers three main representatives of this group: halloysite, imogolite and chrysotile. These hydrosilicates have the ability of spontaneous curling (scrolling) due to a number of crystal structure features, including the size and chemical composition differences between the sheets, (or the void in the gibbsite sheet and SiO2 tetrahedron, in the case of imogolite). Mineral nanoscrolls and nanotubes consist of the most abundant elements, like magnesium, aluminium and silicon, accompanied by uncontrollable amounts of impurities (other elements and phases), which hinder their high technology applications. The development of a synthetic approach makes it possible to not only to overcome the purity issues, but also to enhance the chemical composition of the nanotubular particles by controllable cation doping. The first part of the review covers some principles of the cation doping approach and proposes joint criteria for the semiquantitative prediction of morphological changes that occur. The second part focuses on some doping-related properties and applications, such as morphological control, uptake and release, magnetic and mechanical properties, and catalysis.

In situobservation of morphological changes of γ′ precipitates in a pre-deformed single-crystal Ni-base superalloy

2011 ◽  
Vol 44 (5) ◽  
pp. 935-944 ◽  
Author(s):  
Pavel Strunz ◽  
Gerhard Schumacher ◽  
Hellmuth Klingelhöffer ◽  
Albrecht Wiedenmann ◽  
Jan Šaroun ◽  
...  
Keyword(s):  
External Load ◽  
Morphological Changes ◽  
The Past ◽  
Subsequent Heating ◽  
Detailed Evaluation ◽  
The Matrix ◽  
Base Superalloy

Exposure of a superalloy to an external load results in anisotropic coarsening of the γ′ precipitates, so-called rafting. It was reported in the past that γ′ rafting can also occur as a result of purely thermal treatment, without the simultaneous presence of an external load, if the specimen has been pre-deformed at relatively low temperature. The evolution of γ′ morphology in pre-deformed specimens of SCA425 Ni-base superalloy was examined in the present study. Unlike in the previous experiments, the compressive stress was used for pre-straining.In situsmall-angle neutron scattering (SANS) was employed, which enabled the determination of the morphology directly at high temperature. Both for strong and for weak pre-straining, rounding of the originally cuboidal precipitates towards an ellipsoidal shape on heating was observed. Weak pre-straining (0.1, 0.5%) does not cause rafting on subsequent heating. On the other hand, the detailed evaluation of SANS data provides some indication of rafting during the subsequent heating after severe compressive pre-straining (2%). The experiment indicates the role of dislocation rearrangement at the matrix/precipitate interface during pre-straining.

scholarly journals Essential Tremor

2015 ◽  
Vol 22 (2) ◽  
pp. 108-118 ◽  
Author(s):  
Elan D. Louis
Keyword(s):  
Essential Tremor ◽  
Dendritic Spines ◽  
Morphological Changes ◽  
Neurological Diseases ◽  
The United States ◽  
The Past ◽  
Degenerative Disorders ◽  
Postmortem Studies ◽  
New Formulation ◽  
Cell Interface

Essential tremor (ET) is one of the most common neurological diseases, with an estimated 7 million affected individuals in the United States. Postmortem studies in the past few years have resulted in new knowledge as well as a new formulation of disease pathophysiology. This new formulation centers on the notion that ET might be a disease of the cerebellum and, more specifically, the Purkinje cell (PC) population. Indeed, several investigators have proposed that ET may be a “Purkinjopathy.” Supporting this formulation are data from controlled postmortem studies demonstrating (1) a range of morphological changes in the PC axon, (2) abnormalities in the position and orientation of PC bodies, (3) reduction in the number of PCs in some studies, (4) morphological changes in and pruning of the PC dendritic arbor with loss of dendritic spines, and (5) alterations in both the PC-basket cell interface and the PC-climbing fiber interface in ET cases. This new formulation has engendered some controversy and raised additional questions. Whether the constellation of changes observed in ET differs from that seen in other degenerative disorders of the cerebellum remains to be determined, although initial studies suggest the likely presence of a distinct profile of changes in ET.

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