On the role of the proventricle region in reproduction and regeneration in Typosyllis antoni (Annelida: Syllidae)

Background: Syllids are a species rich annelid family possessing remarkable regenerative ability, which is not only the response after traumatic injury, but also a key step during the life cycle of several syllid taxa. In these animals the posterior part of the body becomes an epitoke and is later detached as a distinct unit named stolon. Such a sexual reproductive mode is named schizogamy or stolonization. The prostomium and the proventricle, a modified foregut structure, have been proposed to have a control function during this process, though the concrete mechanisms behind it have never been elucidated. Results: By using different experimental set-ups, histology and immunohistochemistry combined with subsequent cLSM analyzes, we investigate and document the regeneration and stolonization in specimens of Typosyllis antoni that were amputated at different levels throughout the antero-posterior body axis. The removal of the anterior end including the proventricle implies an incomplete anterior regeneration as well as severe deviations from the usual reproductive pattern, i.e. accelerated stolonization, masculinization and the occurrence of aberrant stolons. The detailed anatomy of aberrant stolons is described. A histological study of the proventricle revealed no signs of glandular or secretory structures. The ventricle and the caeca are composed of glandular tissue but they are not involved in the reproductive and regenerative processes. Conclusions: As in other investigated syllids, the proventricle region has a significant role during stolonization and reproduction processes in Typosyllis antoni. When the proventricle region is absent, anterior and posterior regeneration are considerably deviated from the general patterns. However, proventricle ultrastructure does not show any glandular component, thereby questioning a direct involvement of this organ itself in the control of reproduction and regeneration. Our findings offer a comprehensive starting point for further studies of regeneration and reproductive control in syllids as well as annelids in general

Morphological investigations of posttraumatic regeneration in Timarete cf. punctata (Annelida: Cirratulidae)

Introduction: Annelids exhibit great regenerative abilities, which are mainly used after injury or during reproduction. These lophotrochozoans thus represent excellent models for regeneration research. However, detailed morphological studies concerning annelid musculature and nervous system redevelopment are limited to few taxa, and do not allow for broader comparisons and general conclusions regarding common patterns amongst annelids. Results: Using immunohistochemical staining combined with confocal laser scanning microscopy (cLSM), we investigated the redevelopment of body wall musculature and nervous system during anterior and posterior posttraumatic regeneration in Timarete cf. punctata. Both regeneration processes start with wound healing, blastema formation, and blastema patterning. In posterior regeneration, this leads to the development of a new pygidium and a segment addition zone (SAZ) anterior to this structure. New segments are subsequently added in a sequential fashion. Anterior regeneration in contrast shows the formation of a new prostomium and peristomium first, followed by the simultaneous redevelopment of three segments, and an additional three segments in sequential order. Anterior muscular regeneration shows an outgrowth of longitudinal musculature from the residual body wall musculature, while circular musculature develops independently within the blastema. During posterior regeneration, new musculature becomes visible when the new segments reached a certain age. Neuronal regeneration begins with neurite outgrowth from the old ventral nerve cord in both cases, which are later forming loop structures. In anterior regeneration, the brain redevelops at the anteriormost position of the loops. Conclusions: Posterior regeneration recapitulates normal growth from a certain timepoint with serial segment development by a posterior segment addition zone. Anterior regeneration is more complex, showing similarities to larval development in matters of the order, in which prostomium, peristomium, and segments are generated. Furthermore, we demonstrate the usefulness of regeneration studies to investigate morphological structures and evolutionary processes

Nervous system regeneration in Typosyllis antoni (Annelida: Syllidae)

Annelids represent a metazoan taxon with remarkable regenerative abilities, used during reproduction as well as after injury. Although many studies of different aspects of annelid regeneration are available, detailed morphological investigations regarding the regeneration of specific organ systems such as the nervous system are scarce. Using immunohistochemical staining techniques combined with subsequent confocal laser scanning microscopy (cLSM) and a 3D-reconstruction based on histological sections of the anterior nervous system in adults for comparison, we investigated the redevelopment of the anterior and posterior nervous system during posttraumatic regeneration in Typosyllis antoni. In both processes, the first signs of a regenerated nervous system are neurites infiltrating the regeneration blastema. During posterior regeneration, the neurites are reorganized in a terminal commissure within the new pygidium. Afterwards, neuronal structures of the ventral nerve cord such as segmental nerves were developed. This occurs in conformity with the development of new segments by the reestablished posterior segment addition zone, comparable to normal growth. During anterior nervous system regeneration, the neurites form loops close to the stump of the remaining nerve cord, that attach its contralateral connectives. Later, these loops become the dorsal and ventral roots of the circumesophageal connectives and the brain reoccurs in an anteriormost position. This kind of anterior regeneration agrees with the general pattern known in annelids.MW thanks the University of Leipzig for funding by scholarship (U00048). CB was supported by a “Ramón y Cajal” fellowship by the MINECO, project n° RYC-2014-15615. MTA was supported by the Spanish Government (Programa José Castillejo) for a research stay at the University of Leipzig. This study is a contribution of the project “Macroevolutionary transitions in Syllidae” CGL2015-63593-P supported by MINECO/FEDER, UEfunds.Peer Reviewe

On the role of the proventricle region in reproduction and regeneration in Typosyllis antoni (Annelida: Syllidae)

© 2016 The Author(s)[Background]: Syllids are a species rich annelid family possessing remarkable regenerative ability, which is not only the response after traumatic injury, but also a key step during the life cycle of several syllid taxa. In these animals the posterior part of the body becomes an epitoke and is later detached as a distinct unit named stolon. Such a sexual reproductive mode is named schizogamy or stolonization. The prostomium and the proventricle, a modified foregut structure, have been proposed to have a control function during this process, though the concrete mechanisms behind it have never been elucidated. Results: By using different experimental set-ups, histology and immunohistochemistry combined with subsequent cLSM analyzes, we investigate and document the regeneration and stolonization in specimens of Typosyllis antoni that were amputated at different levels throughout the antero-posterior body axis. The removal of the anterior end including the proventricle implies an incomplete anterior regeneration as well as severe deviations from the usual reproductive pattern, i.e. accelerated stolonization, masculinization and the occurrence of aberrant stolons. The detailed anatomy of aberrant stolons is described. A histological study of the proventricle revealed no signs of glandular or secretory structures. The ventricle and the caeca are composed of glandular tissue but they are not involved in the reproductive and regenerative processes. Conclusions: As in other investigated syllids, the proventricle region has a significant role during stolonization and reproduction processes in Typosyllis antoni. When the proventricle region is absent, anterior and posterior regeneration are considerably deviated from the general patterns. However, proventricle ultrastructure does not show any glandular component, thereby questioning a direct involvement of this organ itself in the control of reproduction and regeneration. Our findings offer a comprehensive starting point for further studies of regeneration and reproductive control in syllids as well as annelids in general.[Results]: By using different experimental set-ups, histology and immunohistochemistry combined with subsequent cLSM analyzes, we investigate and document the regeneration and stolonization in specimens of Typosyllis antoni that were amputated at different levels throughout the antero-posterior body axis. The removal of the anterior end including the proventricle implies an incomplete anterior regeneration as well as severe deviations from the usual reproductive pattern, i.e. accelerated stolonization, masculinization and the occurrence of aberrant stolons. The detailed anatomy of aberrant stolons is described. A histological study of the proventricle revealed no signs of glandular or secretory structures. The ventricle and the caeca are composed of glandular tissue but they are not involved in the reproductive and regenerative processes.[Conclusions]: As in other investigated syllids, the proventricle region has a significant role during stolonization and reproduction processes in Typosyllis antoni. When the proventricle region is absent, anterior and posterior regeneration are considerably deviated from the general patterns. However, proventricle ultrastructure does not show any glandular component, thereby questioning a direct involvement of this organ itself in the control of reproduction and regeneration. Our findings offer a comprehensive starting point for further studies of regeneration and reproductive control in syllids as well as annelids in general.MW thanks the University of Leipzig for funding by scholarship (U00048). MTA was supported by the Spanish Government (Programa José Castillejo, CAS14/00409) for a research stay at the University of Leipzig. CB is supported by a “Ramón y Cajal” fellowship by the MINECO, project n° RYC-2014- 15615. This study is a contribution of the project “Macroevolutionary transitions in Syllidae” CGL2015-63593-P supported by the MINECO/FEDER, UE funds. We acknowledge support from the German Research Foundation (DFG) and Universität Leipzig within the program of Open Access Publishing.Peer Reviewe

On the role of the proventricle region in reproduction and regeneration in Typosyllis antoni (Annelida: Syllidae)

Background: Syllids are a species rich annelid family possessing remarkable regenerative ability, which is not only the response after traumatic injury, but also a key step during the life cycle of several syllid taxa. In these animals the posterior part of the body becomes an epitoke and is later detached as a distinct unit named stolon. Such a sexual reproductive mode is named schizogamy or stolonization. The prostomium and the proventricle, a modified foregut structure, have been proposed to have a control function during this process, though the concrete mechanisms behind it have never been elucidated. Results: By using different experimental set-ups, histology and immunohistochemistry combined with subsequent cLSM analyzes, we investigate and document the regeneration and stolonization in specimens of Typosyllis antoni that were amputated at different levels throughout the antero-posterior body axis. The removal of the anterior end including the proventricle implies an incomplete anterior regeneration as well as severe deviations from the usual reproductive pattern, i.e. accelerated stolonization, masculinization and the occurrence of aberrant stolons. The detailed anatomy of aberrant stolons is described. A histological study of the proventricle revealed no signs of glandular or secretory structures. The ventricle and the caeca are composed of glandular tissue but they are not involved in the reproductive and regenerative processes. Conclusions: As in other investigated syllids, the proventricle region has a significant role during stolonization and reproduction processes in Typosyllis antoni. When the proventricle region is absent, anterior and posterior regeneration are considerably deviated from the general patterns. However, proventricle ultrastructure does not show any glandular component, thereby questioning a direct involvement of this organ itself in the control of reproduction and regeneration. Our findings offer a comprehensive starting point for further studies of regeneration and reproductive control in syllids as well as annelids in general

On the role of the proventricle region in reproduction and regeneration in Typosyllis antoni (Annelida: Syllidae)

Background: Syllids are a species rich annelid family possessing remarkable regenerative ability, which is not only the response after traumatic injury, but also a key step during the life cycle of several syllid taxa. In these animals the posterior part of the body becomes an epitoke and is later detached as a distinct unit named stolon. Such a sexual reproductive mode is named schizogamy or stolonization. The prostomium and the proventricle, a modified foregut structure, have been proposed to have a control function during this process, though the concrete mechanisms behind it have never been elucidated. Results: By using different experimental set-ups, histology and immunohistochemistry combined with subsequent cLSM analyzes, we investigate and document the regeneration and stolonization in specimens of Typosyllis antoni that were amputated at different levels throughout the antero-posterior body axis. The removal of the anterior end including the proventricle implies an incomplete anterior regeneration as well as severe deviations from the usual reproductive pattern, i.e. accelerated stolonization, masculinization and the occurrence of aberrant stolons. The detailed anatomy of aberrant stolons is described. A histological study of the proventricle revealed no signs of glandular or secretory structures. The ventricle and the caeca are composed of glandular tissue but they are not involved in the reproductive and regenerative processes. Conclusions: As in other investigated syllids, the proventricle region has a significant role during stolonization and reproduction processes in Typosyllis antoni. When the proventricle region is absent, anterior and posterior regeneration are considerably deviated from the general patterns. However, proventricle ultrastructure does not show any glandular component, thereby questioning a direct involvement of this organ itself in the control of reproduction and regeneration. Our findings offer a comprehensive starting point for further studies of regeneration and reproductive control in syllids as well as annelids in general

Additional file 1: Figure S1. of On the role of the proventricle region in reproduction and regeneration in Typosyllis antoni (Annelida: Syllidae)

Schematic representation of four T. antoni. specimens monitored during anterior regeneration after amputation between chaetigers 35 and 36 (amputation site 3). Numbers in the lower right corner refer to the specimen. Grey numbers denote days post amputation, asterisks indicate that at least one day before was not observed. Last drawing of each specimen is always the last day of observation. a Specimen with subsequent development of two male stolons. b Specimen with development of only one female stolon. c Specimen with development of only one male stolon. d Specimen with development of only one male stolon. After stolon detachment, the remaining body broke in parts and only a midbody fragment regenerating its anterior end was found. (TIF 1341 kb

The effect of cytosorb® application on kidney recovery in critically ill patients with severe rhabdomyolysis: a propensity score matching analysis

AbstractSevere rhabdomyolysis frequently results in acute kidney injury (AKI) due to myoglobin accumulation with the need of kidney replacement therapy (KRT). The present study investigated whether the application of Cytosorb® (CS) led to an increased rate of kidney recovery in patients with KRT due to severe rhabdomyolysis. Adult patients with a myoglobin-concentration >10,000 ng/ml and KRT were included from 2014 to 2021. Exclusion criteria were chronic kidney disease and CS-treatment before study inclusion. Groups 1 and 2 were defined as KRT with and without CS, respectively. The primary outcome parameter was independence from KRT after 30 days. Propensity score (PS) matching was performed (predictors: myoglobin, SAPS-II, and age), and the chi2-test was used. 35 pairings could be matched (mean age: 57 vs. 56 years; mean myoglobin: 27,218 vs. 26,872 ng/ml; mean SAPS-II: 77 vs. 76). The probability of kidney recovery was significantly (p = .04) higher in group 1 (31.4 vs. 11.4%, mean difference: 20.0%, odds ratio (OR): 3.6). Considering patients who survived 30 days, kidney recovery was also significantly (p = .03) higher in patients treated with CS (61.1 vs. 23.5%, mean difference: 37.6%, OR: 5.1). In conclusion, the use of CS might positively affect renal recovery in patients with severe rhabdomyolysis. A prospective randomized controlled trial is needed to confirm this hypothesis