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Lindsey N Marshall, Céline J Vivien, Fabrice Girardot, Louise Péricard, Pierluigi Scerbo, Karima Palmier, Barbara A Demeneix, Laurent Coen
Despite therapeutic advances, heart failure is the major cause of morbidity and mortality worldwide, but why cardiac regenerative capacity is lost in adult humans remains an enigma. Cardiac regenerative capacity widely varies across vertebrates. Zebrafish and newt hearts regenerate throughout life. In mice, this ability is lost in the first postnatal week, a period physiologically similar to thyroid hormone (TH)-regulated metamorphosis in anuran amphibians. We thus assessed heart regeneration in Xenopus laevis before, during, and after TH-dependent metamorphosis...
February 12, 2019: Proceedings of the National Academy of Sciences of the United States of America
Shouhong Wang, Lusha Liu, Jiongyu Liu, Wei Zhu, Yuta Tanizaki, Liezhen Fu, Lingyu Bao, Yun-Bo Shi, Jianping Jiang
Thyroid hormone (T3) is essential for vertebrate development, especially during the so-called postembryonic development, a period around birth in mammals when plasma T3 level peaks and many organs mature into their adult form. Compared to embryogenesis, postembryonic development is poorly studied in mammals largely because of the difficulty to manipulate the uterus-enclosed embryos and neonates. Amphibian metamorphosis is independent of maternal influence and can be easily manipulated for molecular and genetic studies, making it a valuable model to study postembryonic development in vertebrates...
2019: Frontiers in Endocrinology
Reiko Okada, Masakazu Suzuki, Nozomi Ito, Susumu Hyodo, Sakae Kikuyama
Prolactin (PRL) is one of the major hormones that control amphibian metamorphosis. Recently, a PRL (PRL1B) gene that is different from the known PRL (PRL1A) gene has been found in the genomes of several amphibian species. In order to ascertain whether the PRL1B gene is expressed in the bullfrog (Rana catesbeiana) pituitary, cloning of cDNA encoding PRL1B in the pituitary of the premetamorphic bullfrog tadpole was attempted. The bullfrog PRL1B amino acid sequence predicted from the obtained cDNA showed 62-63% identity with those of Xenopus PRL1Bs that have been presumed from the genome sequences, whereas the sequence identity between bullfrog PRL1A and PRL1B was 48%...
February 5, 2019: General and Comparative Endocrinology
Mikołaj Kaczmarski, Piotr Tryjanowski, Anna Maria Kubicka
Background: The main aim of the study was to analyse the influence of fleshy fruits (plums) on the post-metamorphic growth and feeding behaviour of the green toad Bufotes viridis . We tested the following two hypotheses: (1) juveniles of the green toad are characterised by faster growth in conditions involving fallen plums Prunus cerasifera due to the associated presence of more varied food such as invertebrates; (2) green toads exhibit more active feeding behaviour in the presence of fleshy fruits...
2019: PeerJ
Michaela Kolker, Shai Meiri, Roi Holzman
The morphology of organisms reflects a balance between their evolutionary history, functional demands, and biomechanical constraints imposed by the immediate environment. In many fish species, a marked shift in the selection regime is evident when pelagic larvae, which swim and feed in the open ocean, settle in their adult benthic habitat. This shift is particularly dramatic in coral-reef fishes, where the adult habitat is immensely complex. However, whether the adult trophic ecotype affects the morphology of early life stages is unclear...
February 5, 2019: Evolution; International Journal of Organic Evolution
Shiori Nakazawa, Maki Shirae-Kurabayashi, Hitoshi Sawada
In the ascidian Ciona robusta (formerly C. intestinalis type A), the mechanism underlying sperm penetration through the egg investment remains unknown. We previously reported that proteins containing both an astacin metalloprotease domain and thrombospondin type 1 repeats are abundant in the sperm surface protein-enriched fraction of C. robusta. Here we investigated the involvement of those proteins in fertilisation. We refined the sequences of astacin metalloproteases, confirmed that five of them are present in the sperm, and labelled them as tunicate astacin and thrombospondin type 1 repeat-containing (Tast) proteins...
January 30, 2019: Scientific Reports
Urtzi Enriquez-Urzelai, Martina Sacco, Antonio S Palacio, Pol Pintanel, Miguel Tejedo, Alfredo G Nicieza
Complex life-histories may promote the evolution of different strategies to allow optimal matching to the environmental conditions that organisms can encounter in contrasting environments. For ectothermic animals, we need to disentangle the role of stage-specific thermal tolerances and developmental acclimation to predict the effects of climate change on spatial distributions. However, the interplay between these mechanisms has been poorly explored. Here we study whether developmental larval acclimation to rearing temperatures affects the thermal tolerance of subsequent terrestrial stages (metamorphs and juveniles) in common frogs (Rana temporaria)...
January 29, 2019: Oecologia
Diogo Costa, John W Pomeroy
Seasonal snowcovers release nutrients accumulated over the winter during spring snowmelt and this can be an important part of the annual biogeochemical cycling of chemicals and their loading to soils and water bodies. The characteristics of this load are controlled by snowmelt dynamics and the physical and chemical properties of the snowpack, which are affected by overwinter and snowmelt metamorphism, refreezing of meltwater, and ion exclusion from snow crystals. Rain-on-snow (ROS) events can accelerate and modify the snowpack discharge process...
January 21, 2019: Science of the Total Environment
Liping Luan, Xiao Wang, Hao Zheng, Liuqingqing Liu, Xianxiang Luo, Fengmin Li
Little knowledge is available on impact of microplastics (MPs) on the bivalve larvae at different developmental stages throughout their life history, especially for metamorphic stage. Therefore, this study aims to evaluate the toxic responses of carboxylated (PS-COOH) and amino (PS-NH2 ) polystyrene MPs on the developing clam larvae at three key life stages, i.e., fertilized eggs, D-veliger larvae, and umbo larvae. PS-COOH and PS-NH2 significantly decreased the hatching rates by 5.79-39.5% and developmental rates by 4...
February 2019: Marine Pollution Bulletin
Gabriela Beatriz Olea, Esteban Omar Cheij, Lucila Marilen Curi, Ana Paula Cuzziol Boccioni, Jorge Abel Céspedez, Daniel Marcelo Lombardo
A detailed description of the tegument and parotoid glands of pre-metamorphic, post-metamorphic, juvenile and adult individuals of Rhinella bergi is presented to provide an exhaustive analysis of the integumentary characteristics of this species. Fragments of the tegument were fixed in Bouin solution and preserved in buffered Formol 10%. Subsequently, scanning electron microscopy (SEM) was performed to characterize the macroscopic structure of these regions. Microscopic observations were made from histological sections stained with Hematoxylin and Eosin, Alcian Blue (pH 2,5), PAS-H, Coomassie Blue, Oil Red, and Bielschowsky Impregnation...
January 21, 2019: Acta Histochemica
Wenjun Zhang, Li Chen, Yuanyuan Xu, Yue Deng, Luyao Zhang, Yinan Qin, Zikang Wang, Rui Liu, Zhiqiang Zhou, Jinling Diao
Pesticides are a major cause of reduction in the global population of amphibians. This study investigates the effect of varying concentrations of cyproconazole (1 and 10 mg/L) on Rana nigromaculata during a chronic 90 days exposure period. High levels of cyproconazole (10 mg/L) induced declined body weight, short snout-vent length, slow metamorphic development and abnormal behavioral endpoints in R. nigromaculata tadpoles. Tadpoles exposed to 10 mg/L did not survive beyond 42 days. Abnormal behaviors were observed more frequently with exposure to the highest concentration of cyproconazole...
January 3, 2019: Aquatic Toxicology
Robert E London
There has been a steadily increasing appreciation of the fact that the relationship between protein sequence and structure is often sufficiently ambiguous to allow a single sequence to adopt alternative, stable folds. Living organisms have been able to utilize such metamorphic proteins in remarkable and unanticipated ways. HIV-1 reverse transcriptase is among the earliest such proteins identified and remains a unique example in which a functional heterodimer contains two, alternatively folded polymerase domains...
December 17, 2018: Structure
Gyunghee Lee, Ritika Sehgal, Zixing Wang, Jae H Park
In Drosophila melanogaster a significant number of heterogenous larval neurons in the central nervous system undergo metamorphosis-associated programmed cell death, termed metamorphoptosis. Interestingly distinct groups of doomed larval neurons are eliminated at different metamorphic phases. Although ecdysone hormonal signaling via nuclear ecdysone receptors (EcRs) is known to orchestrate the neuronal metamorphoptosis, little is known about how this signaling controls such diverse neuronal responses. Crustacean cardioactive peptide (CCAP)-producing neurons in the ventral nerve cord are developmentally programmed to die shortly after adult emergence...
January 14, 2019: Apoptosis: An International Journal on Programmed Cell Death
Paul Z Hanakata, Ekin D Cubuk, David K Campbell, Harold S Park
Making kirigami-inspired cuts into a sheet has been shown to be an effective way of designing stretchable materials with metamorphic properties where the 2D shape can transform into complex 3D shapes. However, finding the optimal solutions is not straightforward as the number of possible cutting patterns grows exponentially with system size. Here, we report on how machine learning (ML) can be used to approximate the target properties, such as yield stress and yield strain, as a function of cutting pattern. Our approach enables the rapid discovery of kirigami designs that yield extreme stretchability as verified by molecular dynamics (MD) simulations...
December 21, 2018: Physical Review Letters
Tara A Janes, Stephanie Fournier, Simon Chamberland, Gregory D Funk, Richard Kinkead
Amphibian respiratory development involves a dramatic metamorphic transition from gill- to lung-breathing, and coordination of distinct motor outputs. To determine whether the emergence of adult respiratory motor patterns was associated with similarly dramatic changes in motoneuron (MN) properties, we characterized the intrinsic electrical properties of American bullfrog trigeminal MNs innervating respiratory muscles comprising the buccal pump. In pre-metamorphic tadpoles (TK stages IX-XVIII) and adult frogs, morphometric analyses and whole-cell recordings were performed in trigeminal MNs identified using fluorescent retrograde labeling...
January 2, 2019: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
Amanda M Kissel, Wendy J Palen, Maureen E Ryan, Michael J Adams
Anthropogenic climate change presents challenges and opportunities to the growth, reproduction, and survival of individuals throughout their life cycles. Demographic compensation among life-history stages has the potential to buffer populations from decline, but alternatively, compounding negative effects can lead to accelerated population decline and extinction. In montane ecosystems of the U.S. Pacific Northwest, increasing temperatures are resulting in a transition from snow-dominated to rain-dominated precipitation events, reducing snowpack...
December 27, 2018: Ecological Applications: a Publication of the Ecological Society of America
Lorenzo Alibardi
Organ regeneration occurs in anamniotes (fish and amphibians) while is absent in amniotes (reptiles, birds and mammals). An evolutionary hypothesis is presented to explain the loss of organ regeneration in amniotes. The aquatic life in fish or the initial aquatic and later terrestrial life in amphibians requires complex life cycles after embryonic development. One or more larval stages that occupy different ecological niches are necessary in fish to reach the final adult stage, generally through metamorphosis...
December 20, 2018: Annals of Anatomy, Anatomischer Anzeiger: Official Organ of the Anatomische Gesellschaft
Zhiyi Zhang, Xiaoyuan Xie
In the rapidly growing field of big data analysis, scientists from numerous domains such as computer science and biology are constantly challenged by an unprecedented amount of data. While many software programs have been constructed to support processing and analyzing continuous information flow, one under-appreciated challenge in this field is software quality assurance of these big data software platforms. Metamorphic testing, which was proposed to alleviate the oracle problem in the software engineering community, has become an effective approach for software verification and validation...
December 18, 2018: Biophysical Reviews
Maria Mandela Prünster, Lorenzo Ricci, Federico D Brown, Stefano Tiozzo
During metamorphosis of solitary ascidians, part of the larval tubular nervous system is recruited to form the adult central nervous system (CNS) through neural stem-like cells called ependymal cells. The anteroposterior (AP) gene expression patterning of the larval CNS regionalize the distribution of the ependymal cells, which contains the positional information of the neurons of the adult nervous system. In colonial ascidians, the CNS of asexually developed zooids has the same morphology of the one of the post-metamorphic zooids...
October 25, 2018: Developmental Biology
Artur Feld, Agnes Weimer, Andreas Kornowski, Naomi Winckelmans, Jan-Philip Merkl, Hauke Kloust, Robert Zierold, Christian Schmidtke, Theo Schotten, Maria Riedner, Sara Bals, Horst Weller Prof Dr
Herein we demonstrate that meticulous and in-depth analysis of the reaction mechanisms of nanoparticle formation is rewarded by full control of size, shape and crystal structure of superparamagnetic iron oxide nanocrystals during synthesis. Starting from two iron sources - iron(II)- and iron(III) carbonate -a strict separation of oleate formation from the generation of reactive pyrolysis products and concomitant nucleation of iron oxide nanoparticles was achieved. This protocol enabled us to analyze each step of nanoparticle formation independently in depth...
December 12, 2018: ACS Nano
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