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Qiran Chen, Hayato Yokoi, Tohru Suzuki
Retinoic acid (RA) plays various embryogenesis and post-embryogenesis roles in vertebrates. As exposure of metamorphosing flounder larvae to RA has teratogenic effects on skin color and vertebral column development, harmonized RA synthesis and catabolism are likely essential in metamorphic development. To approach understanding of the roles of RA in flounder metamorphic development, we here examined the tissue mRNA expression of RA synthases (aldh1a1, aldh1a2, aldh1a3) and catabolic enzymes (cyp26a1, cyp26b1, cyp26c1) in newly hatched and metamorphosing larvae, and three-month-old juveniles by in situ hybridization (ISH)...
August 9, 2018: General and Comparative Endocrinology
Stefano Gianni, Michelle McCully, Francesca Malagrinò, Daniela Bonetti, Alfonso De Simone, Maurizio Brunori, Valerie Daggett
Metamorphic proteins are biomolecules prone to adopt alternative conformations. Because of this feature, they represent ideal systems to investigate the general rules allowing primary structure to dictate protein topology. Here we performed a comparative molecular dynamics study on the denatured states of two proteins sharing nearly identical amino acid sequence (88%) but different topology, namely an all-α-helical bundle protein named GA88, and an α+β-protein, named GB88. The analysis allowed us to successfully design, and to validate experimentally, a site-directed mutant that promotes at least in part the fold switch from GB88 to GA88...
August 10, 2018: Angewandte Chemie
K Terada, Y Sano, N Takahata, A Ishida, A Tsuchiyama, T Nakamura, T Noguchi, Y Karouji, M Uesugi, T Yada, M Nakabayashi, K Fukuda, H Nagahara
Understanding the origin and evolution of near-Earth asteroids (NEAs) is an issue of scientific interest and practical importance because NEAs are potentially hazardous to the Earth. However, when and how NEAs formed and their evolutionary history remain enigmas. Here, we report the U-Pb systematics of Itokawa particles for the first time. Ion microprobe analyses of seven phosphate grains from a single particle provide an isochron age of 4.64 ± 0.18 billion years (1σ). This ancient phosphate age is thought to represent the thermal metamorphism of Itokawa's parent body, which is identical to that of typical LL chondrites...
August 7, 2018: Scientific Reports
Susana Galante-Oliveira, António Pereira, Tiago Baptista, Fernanda Guimarães, Jorge Soares, José Carlos Lopes, Jorge Machado, Carlos Barroso
Statoliths are nonskeletal calcified structures included in most invertebrates' gravireceptors. They have been identified and characterized in several gastropod and cephalopod molluscs and have proved to be very useful for age estimation, growth studies, and connectivity analysis, among other applications. Beyond the scarce available records on their occurrence in Class Bivalvia, statoliths are yet to be documented in the grooved carpet shell, Ruditapes decussatus, a species of high ecological and commercial value...
August 3, 2018: Microscopy and Microanalysis
Katharina Ruthsatz, Kathrin H Dausmann, Claudia Drees, Laura I Becker, Lisa Hartmann, Janica Reese, Nikita M Sabatino, Myron A Peck, Julian Glos
Chemical, physical and biological environmental stressors may affect the endocrine system, such as the thyroid hormone (TH) axis in larval amphibians with consequences for energy partitioning among development, growth and metabolism. We studied the effects of two TH level affecting compounds, exogenous l-thyroxine (T4 ) and sodium perchlorate (SP), on various measures of development and body condition in larvae of the African clawed frog (Xenopus laevis). We calculated the scaled mass index, hepatosomatic index and relative tail muscle mass as body condition indices to estimate fitness...
July 30, 2018: Journal of Applied Toxicology: JAT
Frédéric Girault, Lok Bijaya Adhikari, Christian France-Lanord, Pierre Agrinier, Bharat P Koirala, Mukunda Bhattarai, Sudhan S Mahat, Chiara Groppo, Franco Rolfo, Laurent Bollinger, Frédéric Perrier
Fluid-earthquake interplay, as evidenced by aftershock distributions or earthquake-induced effects on near-surface aquifers, has suggested that earthquakes dynamically affect permeability of the Earth's crust. The connection between the mid-crust and the surface was further supported by instances of carbon dioxide (CO2 ) emissions associated with seismic activity, so far only observed in magmatic context. Here we report spectacular non-volcanic CO2 emissions and hydrothermal disturbances at the front of the Nepal Himalayas following the deadly 25 April 2015 Gorkha earthquake (moment magnitude Mw  = 7...
July 27, 2018: Nature Communications
Vlad K Kumirov, Emily M Dykstra, Branwen M Hall, William J Anderson, Taylor N Szyszka, Matthew H J Cordes
New protein folds may evolve from existing folds through metamorphic evolution involving a dramatic switch in structure. To mimic pathways by which amino-acid sequence changes could induce a change in fold, we designed two folded hybrids of Xfaso 1 and Pfl 6, a pair of homologous Cro protein sequences with ~40% identity but different folds (all-α vs. α+β, respectively). Each hybrid, XPH1 or XPH2, is 85% identical in sequence to its parent, Xfaso 1 or Pfl 6, respectively; 55% identical to its noncognate parent; and ~70% identical to the other hybrid...
July 27, 2018: Protein Science: a Publication of the Protein Society
Christophe Kahlfuss, Thomas Gibaud, Sandrine Denis-Quanquin, Shagor Chowdhury, Guy Royal, Floris Chevallier, Eric Saint-Aman, Christophe Bucher
We have developed a strategy enabling control over the organization of ditopic molecular tectons within a palladium-based self-assembled system. The key electron-responsive sub-unit is a viologen-based mechanical hinge that can toggle under electric stimulation between a folded and a stretched position, the driving force of the folding motion being the π-dimerisation of the electrogenerated viologen cation radicals. The title ditopic tecton features two planar, N2-type, triazole/pyridine-based bidentate binding units, providing the tecton with the ability to chelate two palladium ions both in its folded and in its elongated conformations...
July 27, 2018: Chemistry: a European Journal
Kacey L Dananay, Michael F Benard
Artificial light at night (ALAN) affects over 20% of the earth's surface and is estimated to increase 6% per year. Most studies of ALAN have focused on a single mechanism or life stage. We tested for indirect and direct ALAN effects that occurred by altering American toads' ( Anaxyrus americanus ) ecological interactions or by altering toad development and growth, respectively. We conducted an experiment over two life stages using outdoor mesocosms and indoor terraria. In the first phase, the presence of ALAN reduced metamorphic duration and periphyton biomass...
July 4, 2018: Proceedings. Biological Sciences
Chong Chen, Katrin Linse, Katsuyuki Uematsu, Julia D Sigwart
Life stages of some animals, including amphibians and insects, are so different that they have historically been seen as different species. 'Metamorphosis' broadly encompasses major changes in organism bodies and, importantly, concomitant shifts in trophic strategies. Many marine animals have a biphasic lifestyle, with small pelagic larvae undergoing one or more metamorphic transformations before settling into a permanent, adult morphology on the benthos. Post-settlement, the hydrothermal vent gastropod Gigantopelta chessoia experiences a further, cryptic metamorphosis at body sizes around 5-7 mm ...
July 11, 2018: Proceedings. Biological Sciences
Turan Demircan, Guvanch Ovezmyradov, Berna Yıldırım, İlknur Keskin, Ayşe Elif İlhan, Ece Cana Fesçioğlu, Gürkan Öztürk, Süleyman Yıldırım
Axolotl (Ambystoma mexicanum) is a critically endangered salamander species and a model organism for regenerative and developmental biology. Despite life-long neoteny in nature and in captive-bred colonies, metamorphosis of these animals can be experimentally induced by administering Thyroid hormones (THs). However, microbiological consequences of this experimental procedure, such as host microbiota response, remain largely unknown. Here, we systematically compared host bacterial microbiota associated with skin, stomach, gut tissues and fecal samples, between neotenic and metamorphic axolotls based on 16S rRNA gene sequences...
July 20, 2018: Scientific Reports
Swapnil Shewale, Ishfaq Ali, Kavita Hadawale, Shobha Bhargava
The central control of feeding in animals depends upon the alternating actions of orexigenic and anorectic peptides. Studies at understanding the food intake mechanisms have emphasised the role of Neuropeptide Y as a potent orexigenic peptide in the brain. The aim of this study is to investigate the response of NPY system to positive and negative energy states and elucidate a holistic response of NPY expression throughout the brain of a tadpole model. The pre-metamorphic tadpoles of Euphlyctis cyanophlyctis were subjected to fasting, or intra-cranially injected with glucose or 2-deoxy-d-Glucose (2DG)-a metabolic antagonist of glucose and the response of the NPY system in the entire brain was studied using immunohistochemistry...
June 14, 2018: Neuropeptides
Cheng Xu, Jindřich Kynický, Wenlei Song, Renbiao Tao, Zeng Lü, Yunxiu Li, Yueheng Yang, Miroslav Pohanka, Michaela V Galiova, Lifei Zhang, Yingwei Fei
The absence of low-thermal gradients in old metamorphic rocks (<350 °C GPa-1 ) has been used to argue for a fundamental change in the style of plate tectonics during the Neoproterozoic Era. Here, we report data from an eclogite xenolith in Paleoproterozoic carbonatite in the North China craton that argues for cold subduction as early as 1.8 Ga. The carbonatite has a sediment-derived C isotope signature and enriched initial Sr-Nd isotope composition, indicative of ocean-crust components in the source...
July 17, 2018: Nature Communications
Caitlin T Rumrill, David E Scott, Stacey L Lance
Species with complex life cycles are susceptible to environmental stressors across life stages, but the carryover and latent effects between stages remain understudied. For species with biphasic life histories, such as pond-breeding amphibians, delayed effects of aquatic conditions can influence terrestrial juveniles and adults directly or indirectly, usually mediated through fitness correlates such as body size. We collected adult southern toads (Anaxyrus terrestris) from two source populations - a natural reference wetland and a metal-contaminated industrial wetland - and exposed their offspring to two aquatic stressors - a metal contaminant, copper (Cu), and a dragonfly predator cue - in outdoor mesocosms (n = 24)...
July 9, 2018: Environmental Toxicology and Chemistry
Fang-Min Zhou, Yun-Ying Huang, Tian Tian, Xiao-Yan Li, Yong-Bo Tang
Purpose: Chloride channel-3 (ClC-3) is a member of the chloride channel family and plays a critical role in a variety of cellular activities. The aim of the present study is to explore the molecular mechanisms underlying the antitumor effect of silencing ClC-3 in breast cancer. Methods: Human breast cancer cell lines MDA-MB-231 and MCF-7 were used in the experiments. Messenger RNA and protein expression were examined by quantitative real-time polymerase chain reaction and western blot analysis...
June 2018: Journal of Breast Cancer
Lusha Liu, Wei Zhu, Jiongyu Liu, Shouhong Wang, Jianping Jiang
BACKGROUND: Anuran metamorphosis, which is obligatorily initiated and sustained by thyroid hormone (TH), is a dramatic example of extensive morphological, biochemical and cellular changes occurring during post-embryonic development. Thus, it provides an ideal model to understand the actions of the hormone and molecular mechanisms underlying these developmental and apoptotic processes. In addition to transcriptional factors, microRNAs (miRNAs) play key roles in diverse biological processes via post-transcriptional repression of mRNAs...
June 28, 2018: BMC Genomics
Xiang-Yang Liu, Ilke Arslan, Bruce W Arey, Justin Hackley, Vincenzo Lordi, Christopher J K Richardson
Understanding the atomically precise arrangement of atoms at epitaxial interfaces is important for emerging technologies such as quantum materials that have function and performance dictated by bonds and defects that are energetically active on the micro-electronvolt scale. A combination of atomistic modeling and dislocation theory analysis describes both primary and secondary dislocation networks at the metamorphic Al/Si (111) interface, which is experimentally validated by atomic resolution scanning transmission electron microscopy...
July 24, 2018: ACS Nano
Davide Gulotta, Federica Villa, Francesca Cappitelli, Lucia Toniolo
Stone architectural heritage exposed outdoor represents a challenging habitat for biological growths; nevertheless, biocolonization on heritage structure is ubiquitous and represents a major mechanism of alteration. However, the identification of specific microorganisms with known reactivity towards the stone substrate does not necessarily imply that a biodeterioration process is in progress and, in specific conditions, bioprotection effects have been highlighted as a result of colonization. The main objective of the present research is to evaluate the biofilm formation on different lithotypes exposed to similar environmental polluted conditions, and to investigate whether the presence of subaerial biofilms can be associated to an increased magnitude of deterioration of the colonized surfaces with respect to the not colonized ones...
October 15, 2018: Science of the Total Environment
Robin J Van Meter, Donna A Glinski, S Thomas Purucker, W Matthew Henderson
Pesticide use in agricultural areas requires the application of numerous chemicals to control target organisms, leaving non-target organisms at risk. The present study evaluates the hepatic metabolomic profile of one group of non-target organisms, amphibians, after exposure to a single pesticide and pesticide mixtures. Five common-use pesticide active ingredients were used in this study, three herbicides (atrazine, metolachlor and 2,4-d), one insecticide (malathion) and one fungicide (propiconazole). Juvenile green frogs (Lithobates clamitans) were reared for 60-90days post-metamorphosis then exposed to a single pesticide or a combination of pesticides at the labeled application rate on soil...
May 15, 2018: Science of the Total Environment
F Orton, M Säfholm, E Jansson, Y Carlsson, A Eriksson, J Fick, T Uren Webster, T McMillan, M Leishman, B Verbruggen, T Economou, C R Tyler, C Berg
Amphibians are threatened on a global scale and pollutants may be contributing to population declines, but how chemicals impact on their reproduction is poorly understood. We conducted a life cycle analysis to investigate the impacts of early life exposure to two anti-androgens (exposure until completion of metamorphosis;stage 66): flutamide, (50 µg/L)/linuron (9 and 45 µg/L)) on sexual development and breeding competence in Xenopus tropicalis. Our analyses included: mRNA levels of dmrt1, cyp17, amh, cyp19, foxl2 and ar (tadpoles/metamorphs), gonadal histomorphology (metamorphs/adults), mRNA levels of ar/gr (adult male brain/gonad/forelimb), testosterone/corticosterone levels (adult males), secondary sexual characteristics (forelimb width/nuptial pad: adult males) and breeding competence (amplexus/fertility: adult males)...
June 14, 2018: Scientific Reports
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