Journal articles on the topic 'Danno e plasticità'
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1
Finizio, F. S., and E. Galassi. "Ematomi extradurali nell'infanzia e nell'adolescenza." Rivista di Neuroradiologia 5, no. 1_suppl (April 1992): 45–50. http://dx.doi.org/10.1177/19714009920050s109.
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Gli autori descrivono i principali aspetti TC della loro casistica di 21 EED dell'infanzia e dell'adolescenza, tutti sottoposti a verifica chirurgica, osservati nella Divisione di Neurochirurgia II dell'Ospedale Bellaria di Bologna dal 1985 al 1990. Gli EED sono risultati più frequenti rispetto agli ematomi sottodurali acuti e cronici (8 casi). La possibile presenza di un EED in assenza di fratture craniche è più alta in età pediatrica rispetto a quella adulta: in 4/21 (20%) dei nostri casi non erano riscontrabili fratture all'esame diretto del cranio. La localizzazione esclusivamente frontale, ritenuta rara in passato, era dimostrabile con discreta frequenza (in 3 casi su 21) (14%). in 3/5 (60%) pazienti con lesioni intradurali associate e complicanze neurologiche si osservarono frequentemente falde ematiche di notevole spessore (≥ 3 cm) e aspetti di disomogenità della falda stessa. Peraltro EED di rilevanti proporzioni sono stati ben tollerati in un numero elevato di casi (2/5 40% della nostra serie) senza lesioni intradurali associate; tale dato dipende da fattori anatomici (pervietà della fontanella anteriore, distensibilità delle suture, presenza di ampi spazi extracerebrali e cisternali) e fisiologici (reversibilità del danno cerebrale plasticità) propri dell'encefalo infantile. Infine è importante sottoporre i pazienti a TC successivi all'intervento: aspetti ipodensi esito di processi edematosi e/o lacero-contusivi e atrofia corticale localizzata e/o diffusa) furono riscontrati in 6 pazienti su 21 (20%). Tali dati rivestono particolare importanza per la prognosi del paziente pediatrico.
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Vulesevic, B., and S. F. Perry. "Developmental plasticity of ventilatory control in zebrafish, Danio rerio." Respiratory Physiology & Neurobiology 154, no. 3 (December 2006): 396–405. http://dx.doi.org/10.1016/j.resp.2006.01.001.
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Vulesevic, B. "Chemoreceptor plasticity and respiratory acclimation in the zebrafish Danio rerio." Journal of Experimental Biology 209, no. 7 (April 1, 2006): 1261–73. http://dx.doi.org/10.1242/jeb.02058.
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Schaefer, J., and A. Ryan. "Developmental plasticity in the thermal tolerance of zebrafish Danio rerio." Journal of Fish Biology 69, no. 3 (September 2006): 722–34. http://dx.doi.org/10.1111/j.1095-8649.2006.01145.x.
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Engeszer, Raymond E., Laura Alberici Da Barbiano, Michael J. Ryan, and David M. Parichy. "Timing and plasticity of shoaling behaviour in the zebrafish, Danio rerio." Animal Behaviour 74, no. 5 (November 2007): 1269–75. http://dx.doi.org/10.1016/j.anbehav.2007.01.032.
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Roy, Tamal, and Robert Arlinghaus. "Size-selective mortality fosters ontogenetic changes in collective risk-taking behaviour in zebrafish, Danio rerio." Oecologia 200, no. 1-2 (October 2022): 89–106. http://dx.doi.org/10.1007/s00442-022-05256-y.
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AbstractSize-selective mortality is common in fish populations and can operate either in a positive size-selective fashion by harvesting larger-than-average fish or be negatively size-selective by harvesting smaller-than-average fish. Through various mechanisms (like genetic correlations among behaviour and life-history traits or direct selection on behaviour co-varying with growth rate or size-at-maturation), size-selection can result in evolutionary changes in behavioural traits. Theory suggests that both positive and negative size-selection without additional selection on behaviour favours boldness, while evolution of shyness is possible if the largest fish are harvested. Here we examined the impact of size-selective mortality on collective boldness across ontogeny using three experimental lines of zebrafish (Daniorerio) generated through positive (large-harvested), negative (small-harvested) and random (control line) size-selective mortality for five generations and then relaxed selection for 10 generations to examine evolutionarily fixed outcomes. We measured collective risk-taking during feeding (boldness) under simulated aerial predation threat, and across four contexts in presence/absence of a cichlid. Boldness decreased across ontogeny under aerial predation threat, and the small-harvested line was consistently bolder than controls. The large and small-harvested lines showed higher behavioural plasticity as larvae and developed personality earlier compared to the controls. The large-harvested line showed increased variability and plasticity in boldness throughout ontogeny. In the presence of a live predator, fish did not differ in boldness in three contexts compared to the controls, but the large-harvested line showed reduced behavioural plasticity across contexts than controls. Our results confirmed theory by demonstrating that size-selective harvesting evolutionarily alters collective boldness and its variability and plasticity.
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Bhat, Anuradha, Melissa M. Greulich, and Emília P. Martins. "Behavioral Plasticity in Response to Environmental Manipulation among Zebrafish (Danio rerio) Populations." PLOS ONE 10, no. 4 (April 30, 2015): e0125097. http://dx.doi.org/10.1371/journal.pone.0125097.
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Simmonds, Alec I. M., and Frank Seebacher. "Histone deacetylase activity modulates exercise-induced skeletal muscle plasticity in zebrafish (Danio rerio)." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 313, no. 1 (July 1, 2017): R35—R43. http://dx.doi.org/10.1152/ajpregu.00378.2016.
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Aerobic exercise has a positive impact on animals by enhancing skeletal muscle function and locomotor performance. Responses of skeletal muscle to exercise involve changes in energy metabolism, calcium handling, and the composition of contractile protein isoforms, which together influence contractile properties. Histone deacetylases (HDAC) can cause short-term changes in gene expression and may thereby mediate plasticity in contractile properties of skeletal muscle in response to exercise. The aim of this project was to determine (in zebrafish, Danio rerio) the traits that mediate interindividual differences in sustained and sprint performance and to determine whether inhibiting class I and II HDACs mediates exercise-induced changes in these traits. High sustained performers had greater aerobic metabolic capacity [citrate synthase (CS) activity], calcium handling capacity [sarco/endoplasmic reticulum ATPase (SERCA) activity], and slow contractile protein concentration [slow myosin heavy chain (MHC)] compared with low performers. High sprint performers had lower CS activity and slow MHC concentrations compared with low performers, but there were no significant differences in lactate dehydrogenase activity or fast MHC concentrations. Four weeks of aerobic exercise training increased sustained performance, CS activity, SERCA activity, and slow MHC concentration. Inhibiting class I and II HDACs increased slow MHC concentration in untrained fish but not in trained fish. However, inhibiting HDACs reduced SERCA activity, which was paralleled by a reduction in sustained and sprint performance. The regulation of muscle phenotypes by HDACs could be a mechanism underlying the adaptation of sustained locomotor performance to different environmental conditions, and may therefore be of therapeutic and ecological significance.
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Georga, Ioanna, and George Koumoundouros. "Thermally induced plasticity of body shape in adult zebrafish Danio rerio (Hamilton, 1822)." Journal of Morphology 271, no. 11 (August 16, 2010): 1319–27. http://dx.doi.org/10.1002/jmor.10874.
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Hosseini, Shahrbanou, Bertram Brenig, Jens Tetens, and Ahmad Reza Sharifi. "Phenotypic plasticity induced using high ambient temperature during embryogenesis in domesticated zebrafish, Danio rerio." Reproduction in Domestic Animals 54, no. 3 (December 17, 2018): 435–44. http://dx.doi.org/10.1111/rda.13382.
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Robertson, Cayleih E., Patricia A. Wright, Louise Köblitz, and Nicholas J. Bernier. "Hypoxia-inducible factor-1 mediates adaptive developmental plasticity of hypoxia tolerance in zebrafish, Danio rerio." Proceedings of the Royal Society B: Biological Sciences 281, no. 1786 (July 7, 2014): 20140637. http://dx.doi.org/10.1098/rspb.2014.0637.
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In recent years, natural and anthropogenic factors have increased aquatic hypoxia the world over. In most organisms, the cellular response to hypoxia is mediated by the master regulator hypoxia-inducible factor-1 (HIF-1). HIF-1 also plays a critical role in the normal development of the cardiovascular system of vertebrates. We tested the hypothesis that hypoxia exposures which resulted in HIF-1 induction during embryogenesis would be associated with enhanced hypoxia tolerance in subsequent developmental stages. We exposed zebrafish ( Danio rerio ) embryos to just 4 h of severe hypoxia or total anoxia at 18, 24 and 36 h post-fertilization (hpf). Of these, exposure to hypoxia at 24 and 36 hpf as well as anoxia at 36 hpf activated the HIF-1 cellular pathway. Zebrafish embryos that acutely upregulated the HIF-1 pathway had an increased hypoxia tolerance as larvae. The critical window for hypoxia sensitivity and HIF-1 signalling was 24 hpf. Adult male fish had a lower critical oxygen tension ( P crit ) compared with females. Early induction of HIF-1 correlated directly with an increased proportion of males in the population. We conclude that mounting a HIF-1 response during embryogenesis is associated with long-term impacts on the phenotype of later stages which could influence both individual hypoxia tolerance and population dynamics.
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Schmidt, Kai, and J. Matthias Starck. "Developmental plasticity, modularity, and heterochrony during the phylotypic stage of the zebra fish,Danio rerio." Journal of Experimental Zoology Part B: Molecular and Developmental Evolution 9999B (2009): n/a. http://dx.doi.org/10.1002/jez.b.21320.
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Pan, Tien-Chien Francis, and Ione Hunt von Herbing. "Metabolic plasticity in development: Synergistic responses to high temperature and hypoxia in zebrafish, Danio rerio." Journal of Experimental Zoology Part A: Ecological and Integrative Physiology 327, no. 4 (April 2017): 189–99. http://dx.doi.org/10.1002/jez.2092.
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Yaqoob, Nadeem, and Thorsten Schwerte. "Cardiovascular and respiratory developmental plasticity under oxygen depleted environment and in genetically hypoxic zebrafish (Danio rerio)." Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology 156, no. 4 (August 2010): 475–84. http://dx.doi.org/10.1016/j.cbpa.2010.03.033.
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Craig, Paul M., Chris M. Wood, and Grant B. McClelland. "Gill membrane remodeling with soft-water acclimation in zebrafish (Danio rerio)." Physiological Genomics 30, no. 1 (June 2007): 53–60. http://dx.doi.org/10.1152/physiolgenomics.00195.2006.
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Little is known regarding the ionoregulatory abilities of zebrafish exposed to soft water despite the popularity of this model organism for physiology and aquatic toxicology. We examined genomic and nongenomic changes to gills of zebrafish as they were progressively acclimated from moderately hard freshwater to typical soft water over 7 days and held in soft water for another 7 days. Gills were sampled daily and mRNA expression levels of gill Na+-K+-ATPase (NKA) α1a subunit, epithelium calcium channel (ECaC), carbonic anhydrase-1 and 2 (CA-1, CA-2), Na+/H+ exchanger (NHE-2), V-type proton (H+)-ATPase, and copper transport protein (CTR-1) were quantified by real-time PCR. Changes in enzyme activities of gill NKA were determined and protein levels of NKA and ECaC were quantified by Western blotting. Levels of mRNA for ECaC increased fourfold after day 6, with an associated increase in ECaC protein levels after 1 wk in soft water. CA-1 and CA-2 exhibited a 1.5- and 6-fold increase in gene expression on days 6 and 5, respectively. Likewise, there was a fivefold increase in NHE-2 expression after day 6. Surprisingly, CTR-1 mRNA showed a large transient increase (over threefold) on day 6, while H+-ATPase mRNA did not change. These data demonstrate a high degree of phenotypic plasticity in zebrafish gills exposed to an ion-poor environment. This not only enhances our understanding of ionoregulatory processes in fish but also highlights the need for proper experimental design for studies involving preacclimation to soft water (e.g., metal toxicity).
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Forbes, Erin L., Craig D. Preston, and P. Mark Lokman. "Zebrafish (Danio rerio) and the egg size versus egg number trade off: effects of ration size on fecundity are not mediated by orthologues of the Fec gene." Reproduction, Fertility and Development 22, no. 6 (2010): 1015. http://dx.doi.org/10.1071/rd09257.
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Few studies have demonstrated plasticity of egg size within the confines of an egg size–number trade-off in response to trophic conditions in fishes. Moreover, the physiological mechanisms that govern this plasticity are not known. Growth differentiation factor 9 (Gdf9) and bone morphogenetic factor 15 (Bmp15) are oocyte-specific factors implicated in follicular growth and ovulation in mammals. In order to investigate whether expression levels of these genes were correlated with ration-dependent changes in fecundity in fish, zebrafish (Danio rerio) were subjected to four different feeding regimens. Counts of spawned eggs or vitellogenic follicles were used to estimate fecundity, whereas quantitative polymerase chain reaction analyses were performed to determine Gdf9 and Bmp15 mRNA levels in response to changes in ration size. Both relative fecundity and gonadosomatic index increased significantly with increased ration size, whereas egg size and hatching rate decreased significantly. No significant differences in Gdf9 or Bmp15 transcript abundance were evident between feeding regimens, suggesting that these growth factors do not govern fecundity in fish. However, favourable trophic conditions markedly affected follicle or egg size and number, with important implications for downstream egg quality and survival.
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Morgan, Rachael, Mette H. Finnøen, Henrik Jensen, Christophe Pélabon, and Fredrik Jutfelt. "Low potential for evolutionary rescue from climate change in a tropical fish." Proceedings of the National Academy of Sciences 117, no. 52 (December 14, 2020): 33365–72. http://dx.doi.org/10.1073/pnas.2011419117.
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Climate change is increasing global temperatures and intensifying the frequency and severity of extreme heat waves. How organisms will cope with these changes depends on their inherent thermal tolerance, acclimation capacity, and ability for evolutionary adaptation. Yet, the potential for adaptation of upper thermal tolerance in vertebrates is largely unknown. We artificially selected offspring from wild-caught zebrafish (Danio rerio) to increase (Up-selected) or decrease (Down-selected) upper thermal tolerance over six generations. Selection to increase upper thermal tolerance was also performed on warm-acclimated fish to test whether plasticity in the form of inducible warm tolerance also evolved. Upper thermal tolerance responded to selection in the predicted directions. However, compared to the control lines, the response was stronger in the Down-selected than in the Up-selected lines in which evolution toward higher upper thermal tolerance was slow (0.04 ± 0.008 °C per generation). Furthermore, the scope for plasticity resulting from warm acclimation decreased in the Up-selected lines. These results suggest the existence of a hard limit in upper thermal tolerance. Considering the rate at which global temperatures are increasing, the observed rates of adaptation and the possible hard limit in upper thermal tolerance suggest a low potential for evolutionary rescue in tropical fish living at the edge of their thermal limits.
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Uusi-Heikkilä, S., A. Kuparinen, C. Wolter, T. Meinelt, A. C. O'Toole, and R. Arlinghaus. "Experimental assessment of the probabilistic maturation reaction norm: condition matters." Proceedings of the Royal Society B: Biological Sciences 278, no. 1706 (September 22, 2010): 709–17. http://dx.doi.org/10.1098/rspb.2010.1507.
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The probabilistic maturation reaction norm (PMRN) describes an individual's probability of maturing at a given age as a function of size and other relevant phenotypic traits. Population-level shifts in the PMRN are often interpreted to indicate genetic as opposed to phenotypic changes in maturation in fish. Inferences derived from trends in the PMRN have been challenged, warranting an experimental assessment of the method. This was accomplished in a laboratory experiment using zebrafish ( Danio rerio ). Fish were reared under different food levels to induce variation in growth and maturation. Plasticity in maturation was not entirely captured by the demographic age- and length-based PMRN. Adding condition to the PMRN captured a greater amount of environmental variation in maturation probability. Nevertheless, significant differences in the PMRNs among the food levels remained after accounting for the influences of age, size and condition on maturation probability indicating plasticity of the PMRN. This was particularly pronounced between fish held on low food levels as compared with fish experiencing abundant resources, with the latter experiencing higher size-specific maturation probabilities. Our analysis emphasizes the need for incorporating salient physiological traits influencing maturation, such as condition, to make accurate inferences about documented shifts observed in the position of PMRNs on maturation trends in wild fish stocks.
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Sekhar, M. A., Richa Singh, Anuradha Bhat, and Manjari Jain. "Feeding in murky waters: acclimatization and landmarks improve foraging efficiency of zebrafish ( Danio rerio ) in turbid waters." Biology Letters 15, no. 7 (July 2019): 20190289. http://dx.doi.org/10.1098/rsbl.2019.0289.
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Fish inhabiting human-dominated ecosystems are prone to altered sensory environments in which they must live and function. Increased turbidity is one such change that they must deal with. We tested whether an increase in water turbidity and the presence of visual landmarks (coloured stones) affect the foraging efficiency of wild zebrafish. We also tested the influence of extended exposure to differing turbidity levels on the subsequent foraging efficiency of acclimatized individuals. Feeding latency (time taken to find food) increased significantly with increase in turbidity levels from a minimum of 4 s to ca 300 s. However, extended exposure of fish to varying levels of turbidity decreased feeding latencies in acclimatized conditions, indicating that acclimatization to the immediate visual environment plays an important role in determining foraging success. Most significantly, we found that feeding latencies in turbid conditions decreased significantly if visual landmarks were present. This demonstrates that zebrafish use visual landmark cues to navigate to foraging sites when visibility is impaired. This study has important implications on the role of behavioural plasticity and spatial learning in animals that allow them to cope with altered sensory environments such as episodes of enhanced turbidity that could be natural or anthropogenic.
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Edelmann, Elke, and Volkmar Leßmann. "Die Analyse synaptischer Plastizität auf Einzelzellebene mit Hilfe der STDP." Neuroforum 24, no. 3 (August 28, 2018): 213–21. http://dx.doi.org/10.1515/nf-2017-0064.
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Zusammenfassung Mithilfe des Patch clamp-Verfahrens können die molekularen Prozesse, die der Langzeitpotentierung (LTP) und der Langzeitdepression (LTD) zugrunde liegen, auf der Ebene eines einzelnen postsynaptischen Neurons (Nervenzelle) in akut isolierten Gehirnschnitten untersucht werden. Über die in der Ableitelektrode enthaltene Pipettenlösung können dabei Inhibitoren intrazellulärer Prozesse in das postsynaptische Neuron eingebracht werden, um so die an der synaptischen Plastizität beteiligten Signalwege zu identifizieren. Zur Untersuchung der synaptischen Plastizität wurden in den letzten Jahren zunehmend Protokolle herangezogen, die durch eine minimale Anzahl von synaptischen Stimulationen mit niedriger Frequenz robuste LTP oder LTD auslösen. Zu diesen Stimulationsmustern gehört die sogenannte Spike timing-dependent plasticity (STDP). Sie kann durch wiederholtes nahezu gleichzeitiges Feuern von Aktionspotenzialen (APs) im präsynaptischen und im nachgeschalteten postsynaptischen Neuron induziert werden, wenn diese APs mit einer kurzen zeitlichen Verzögerung von ca. 5–20 ms ausgelöst werden. Während „Vorwärtspaarungen“ mit kurzem positiven Zeitversatz (erst prä- dann postsynaptisches AP) LTP auslösen, führt „Rückwärtspaarung“ (erst post- dann präsynaptisches AP) zu LTD. Zusätzlich zur Abfolge (vorwärts oder rückwärts) und der zeitlichen Verzögerung der APs, ist die Wirkung von neuromodulatorischen Transmittern (z. B. Dopamin, Acetylcholin, Noradrenalin) und die synaptische Freisetzung von intrazellulären Mediatoren der synaptischen Plastizität (z. B. BDNF, Endocannabinoide) kritisch an der Regulation von STDP-Protokollen beteiligt. In diesem Übersichtsartikel fokussieren wir uns auf die Rolle dieser Mediatoren und Modulatoren bei durch STDP ausgelösten synaptischen Plastizitätsphänomenen.
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Vargas, R., I. þ. Jóhannesdóttir, B. Sigurgeirsson, H. þorsteinsson, and K. Æ. Karlsson. "The zebrafish brain in research and teaching: a simple in vivo and in vitro model for the study of spontaneous neural activity." Advances in Physiology Education 35, no. 2 (June 2011): 188–96. http://dx.doi.org/10.1152/advan.00099.2010.
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Recently, the zebrafish ( Danio rerio ) has been established as a key animal model in neuroscience. Behavioral, genetic, and immunohistochemical techniques have been used to describe the connectivity of diverse neural circuits. However, few studies have used zebrafish to understand the function of cerebral structures or to study neural circuits. Information about the techniques used to obtain a workable preparation is not readily available. Here, we describe a complete protocol for obtaining in vitro and in vivo zebrafish brain preparations. In addition, we performed extracellular recordings in the whole brain, brain slices, and immobilized nonanesthetized larval zebrafish to evaluate the viability of the tissue. Each type of preparation can be used to detect spontaneous activity, to determine patterns of activity in specific brain areas with unknown functions, or to assess the functional roles of different neuronal groups during brain development in zebrafish. The technique described offers a guide that will provide innovative and broad opportunities to beginner students and researchers who are interested in the functional analysis of neuronal activity, plasticity, and neural development in the zebrafish brain.
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Tongnunui, Sampan, Treerat Sooksawat, Charoonroj Chotwiwatthanakun, Weerayuth Supiwong, Amnuay Wattanakornsiri, and F. W. H. Beamish. "Seasonal Changes in Upper Thermal Tolerances of Freshwater Thai Fishes." Water 15, no. 2 (January 14, 2023): 350. http://dx.doi.org/10.3390/w15020350.
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Seasonal change inferred to climate change inevitably influences Critical thermal maximum (CTmax) of riverine fishes. In this study, we investigated CTmax as thermal tolerance for four common riverine fishes, i.e., Danio regina, Channa gachua, Rasbora caudimaculata and Mystacoleucus chilopterus, in the Kwae Noi river system in western Thailand. The acute thermal tolerance was lower in the wet season (mean river temperature ∼25 °C) and higher in the dry season (mean river temperature ∼23 °C) with medians of wet season-CTmax for those four fishes of 35.3 ± 0.4, 36.2 ± 0.5, 37.3 ± 0.5 and 37.5 ± 0.6 °C, respectively, and high values of dry season-CTmax of 37.4 ± 0.5, 38.3 ± 0.5, 38.7 ± 0.7 and 39.1 ± 0.5 °C, respectively. The variations of CTmax for all of the four species in this study, throughout the wet and dry seasons, attribute to their seasonal plasticity in response to the dynamics of thermal stress. Under climate variability and climate change with increasing the higher temperatures of air and river, and altering the habitat, R. caudimaculata and M. chilopterus had higher capacities to tolerate the acute heat stress across wet and dry seasons.
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Kavouras, Menelaos, Emmanouil E. Malandrakis, Ewout Blom, Kyriaki Tsilika, Theodoros Danis, Panagiota Panagiotaki, and Athanasios Exadactylos. "Malpigmentation of Common Sole (Solea solea) during Metamorphosis Is Associated with Differential Synaptic-Related Gene Expression." Animals 11, no. 8 (August 1, 2021): 2273. http://dx.doi.org/10.3390/ani11082273.
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In farmed flatfish, such as common sole, color disturbances are common. Dyschromia is a general term that includes the color defects on the blind and ocular sides of the fish. The purpose was to examine the difference in gene expression between normal pigmented and juveniles who present ambicoloration. The analysis was carried out with next-generation sequencing techniques and de novo assembly of the transcriptome. Transcripts that showed significant differences (FDR < 0.05) in the expression between the two groups, were related to those of zebrafish (Danio rerio), functionally identified, and classified into categories of the gene ontology. The results revealed that ambicolorated juveniles exhibit a divergent function, mainly of the central nervous system at the synaptic level, as well as the ionic channels. The close association of chromophore cells with the growth of nerve cells and the nervous system was recorded. The pathway, glutamate binding–activation of AMPA and NMDA receptors–long-term stimulation of postsynaptic potential–LTP (long term potentiation)–plasticity of synapses, appears to be affected. In addition, the development of synapses also seems to be affected by the interaction of the LGI (leucine-rich glioma inactivated) protein family with the ADAM (a disintegrin and metalloprotease) ones.
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Abate, Maria E., Andrew G. Eng, and Les Kaufman. "Alarm cue induces an antipredator morphological defense in juvenile Nicaragua cichlids Hypsophrys nicaraguensis." Current Zoology 56, no. 1 (February 1, 2010): 36–42. http://dx.doi.org/10.1093/czoolo/56.1.36.
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Abstract Olfactory cues that indicate predation risk elicit a number of defensive behaviors in fishes, but whether they are sufficient to also induce morphological defenses has received little attention. Cichlids are characterized by a high level of morphological plasticity during development, and the few species that have been tested do exhibit defensive behaviors when exposed to alarm cues released from the damaged skin of conspecifics. We utilized young juvenile Nicaragua cichlids Hypsophrys nicaraguensis to test if the perception of predation risk from alarm cue (conspecific skin extract) alone induces an increased relative body depth which is a defense against gape-limited predators. After two weeks of exposure, siblings that were exposed to conspecific alarm cue increased their relative body depth nearly double the amount of those exposed to distilled water (control) and zebrafish Danio rerio alarm cue. We repeated our measurements over the last two weeks (12 and 14) of cue exposure when the fish were late-stage juveniles to test if the rate of increase was sustained; there were no differences in final dimensions between the three treatments. Our results show that 1) the Nicaragua cichlid has an innate response to conspecific alarm cue which is not a generalized response to an injured fish, and 2) this innate recognition ultimately results in developing a deeper body at a stage of the life history where predation risk is high.
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Hinojosa, Gabriella, Mia Ruiz, Kassandra Garcia, and Robert Dearth. "RF22 | PMON06 The Contraceptive Synthetic-Progesterone Levonorgestrel (LNG) Significantly Accelerates Fetal Hypothalamic Neuronal Development (Neuroendogenesis) in the Zebrafish (Danio rerio)." Journal of the Endocrine Society 6, Supplement_1 (November 1, 2022): A446. http://dx.doi.org/10.1210/jendso/bvac150.928.
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Abstract The fetal brain has a known vulnerability to exogenous influences due to its plasticity and high volume of replicating and differentiating cells. It is particularly susceptible to a group of environmental molecules classified as endocrine disrupting chemicals (EDCs). Previous vertebrate studies have provided supportive evidence that steroid mimicking EDCs might stimulate hypothalamic progenitor cell differentiation to neurons (neuroendogenesis). Changing the normal timing of neuroendogenesis could play a role in establishing an alternative developmental timeline leading to disruptions in key endocrine regulated process, like pubertal onset. Levonorgestrel (LNG), a synthetic progestin used in contraceptive pills, has been found at physiologically relevant levels in water sources worldwide. Therefore, we investigated the effect LNG had on neuroendogenesis in zebrafish (Danio rerio), an established comparative neurobiological animal model. Fertilized zebrafish embryos were collected (in-house breeding) and individually placed in 96-well plates. Starting at 3 hours post fertilization (hpf), embryos were exposed to either 5 ng of LNG (previously established physiologically relevant dose), 100ng of estradiol (E2, positive control) or a vehicle control for 5 days (5 dpf); covering the duration of neurogenesis. LNG had no effect on fertilization ratios, hatching or morphology compared to controls. On 5 dpf, larvae were paraffin-processed, slides were serially sectioned at (3-4 um) and prepped for immunohistochemistry (IHC). Brain tissue s were stained with hematoxylin and eosin (H&E) to identify regions of the brain including the hypothalamus and thalamus. Brain sections were also stained for the immunofluorescent (IF) neuronal marker α-HUC and/or estrogen receptor (ER) and imaged on a confocal microscope. The number of total cells, positive stained cells and negative stained cells were counted in the preoptic area (POA), rostral hypothalamus (RH) and thalamus, comparisons were made between groups. Interestingly, LNG significantly (p<0.001) increased the number of positive cells expressing α-HUC in the hypothalamus compared to controls. Similar results were observed in the POA (p< 0.01) and RH (p <0.001) compared to their respective controls. Furthermore, we observed no significant changes in α-HUC expression in the thalamus due to LNG treatment comparted to controls. Our data suggests that LNG selectively targets hypothalamic neuronal development, accelerating neuroendogenesis increasing the number of endocrine-regulating neurons in the brain. This is the first study to show that exposure to low environmentally relevant levels of LNG increases neurons in the hypothalamus, thus, highlighting the possibility that LNG may target the brain to potentiate subsequent health issues later in life. Presentation: No date and time listed
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Sumon, Md Afsar Ahmed, Mohammad Habibur Rahman Molla, Israa J. Hakeem, Foysal Ahammad, Ramzi H. Amran, Mamdoh T. Jamal, Mohamed Hosny Gabr, et al. "Epigenetics and Probiotics Application toward the Modulation of Fish Reproductive Performance." Fishes 7, no. 4 (July 28, 2022): 189. http://dx.doi.org/10.3390/fishes7040189.
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Fish represent an excellent source of animal protein as well as a biomedical research model as a result of their evolutionary relatedness and similarity with the human genome. Commercial and ornamental fish culture has achieved popularity, but reproductive dysfunctions act as a limiting factor for quality fry production, interfering with the sustainability of the aquaculture industry. Fish reproduction is crucial for any species’ existence, and reproductive performance can potentially be improved through applications of epigenetics and probiotics. Epigenetics is a highly sensitive molecular approach that includes chromatin structure and function alteration, DNA methylation, and modification of non-coding RNA molecules for the transfer of desired information from parents to offspring. DNA methyltransferase improves reproductive cyp11a1, esr2b, and figla gene expression and feminizes zebrafish (Danio rerio). Moreover, epigenetics also contributes to genome stability, environmental plasticity, and embryonic development. However, methylation of specific genes can negatively affect sperm quality, resulting in poor fertilization. Probiotic administration is able to induce responsiveness of incompetent follicles to maturation-inducing hormones and can change oocyte chemical composition during vitellogenic development. The positive role of probiotics on testicular cells is validated by upregulating the transcription levels of leptin, bdnf, and dmrt1 genes facilitating the spermatogenesis. This review not only discusses the effects and mechanism of epigenetics and probiotics for improving fish reproduction, but also presents an overview of the causal factors and current techniques used to eradicate dysfunction. Moreover, key genes and hormones related to fish reproduction along with research gaps and future prospects are also considered. This review provides an overview of necessary information for students, scientists, researchers, and breeders to resolve fish reproduction-related problems to ensure profitable and sustainable aquaculture.
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Navarro-Guillén, Carmen, Gabriella do Vale Pereira, André Lopes, Rita Colen, and Sofia Engrola. "Egg nutritional modulation with amino acids improved performance in zebrafish larvae." PLOS ONE 16, no. 4 (April 9, 2021): e0248356. http://dx.doi.org/10.1371/journal.pone.0248356.
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New and more efficient methods to sustainably intensify Aquaculture production are essential to attain the seafood demand for direct human consumption in the near future. Nutrition has been identified as one strategy of early exposure that might affect animal early development and later phenotype. This strategy may have positive consequences in the modulation of fish digestive physiology, which will correlate with higher performance outputs. Thus, improving fish digestive efficiency will lead to higher productivity and lower biogenic emission from aquaculture facilities, minimising the impact on the environment while increasing the biological efficiency. An innovative in ovo nutritional modulation technique based on low-frequency ultrasounds was used to enhance the transport of amino acids across the embryo membranes. An early stimulus with either arginine or glutamine, both involved in gut maturation, was applied in zebrafish (Danio rerio) embryos at 3.5 hours post-fertilization (hpf). At 22 days post-fertilization (dpf), growth performance, digestive enzyme activities and gut microbiota composition were analysed to evaluate the larval nutrition-induced metabolic plasticity and the effects on fish digestive efficiency. Results showed that fish survival was not affected either by the sonophoresis technique or amino acid supplementation. Final dry weight at 22 dpf was statistically higher in larvae from glutamine treatment when compared to the control even with lower trypsin activity, suggesting a higher nutrient digestion capacity, due to a slightly modulation of gut microbiota. Higher arginine supplementation levels should be tested as strategy to enhance growth at later developmental stages. In conclusion, this study demonstrated the efficiency of sonophoresis technique for in ovo nutritional modulation and suggests that in ovo glutamine supplementation might promote growth at later developmental stage through a positive microbiota modulation.
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Pelster, B., A. M. Sänger, M. Siegele, and T. Schwerte. "Influence of swim training on cardiac activity, tissue capillarization, and mitochondrial density in muscle tissue of zebrafish larvae." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 285, no. 2 (August 2003): R339—R347. http://dx.doi.org/10.1152/ajpregu.00110.2003.
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Larval zebrafish ( Danio rerio) of two different age classes (“swim-up” larvae, 9 days old; “free-swimming” larvae, 21 days old) were exposed to either an endurance/continuous training or interval training. Control animals were kept in stagnant water. A comparison of cardiac activity of trained (either endurance or interval) and untrained animals at the end of the training regime revealed no differences in heart rate, end-diastolic and end-systolic ventricular volume, and cardiac output. Training also had no influence on the concentration of erythrocytes in the blood. Thus, at the level of total oxygen transport in the blood, training did not provoke any improvement during the first 32 days of development. Significant changes, however, were observed at the tissue level. In free-swimming larvae [i.e., between 21 and 32 days postfertilization (dpf)] endurance training increased the capillarization of both axial muscle caudal to the anus and the tail fin. In addition, mitochondrial density of red and intermediate muscle fibers increased significantly. In contrast to capillarization, even swim-up larvae, trained between 9 and 15 dpf, were affected. The observed increase in mitochondrial content indicates a high demand for oxygen and energy-rich metabolites for oxidative phosphorylation. In older larvae, this is met by the increase in capillarization that improves the blood supply and with it the required oxygen and metabolite supply of muscle tissue. Both of these adaptational changes result in a reduction of diffusion distances (between capillary and muscle fiber as well as mitochondria) and may contribute to a higher resistance toward oxygen deficiency. Furthermore, this study indicates that plasticity of muscle tissue is already established in early stages of development at both the tissue and cellular levels.
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Pessoa, Antônia De Castro Côrtes, Francisco Pessoa Machado, Cláudio Ângelo da Silva Neto, José Antonio Beltrão Sabadia, Cynthia Romariz Duarte, and César Ulisses Vieira Veríssimo. "Aproveitamento dos rejeitos das indústrias de calcinação de calcário na porção setentrional do estado do Ceará com foco na reparação de dano ambiental." Revista Brasileira de Geografia Física 13, no. 3 (June 7, 2020): 1309. http://dx.doi.org/10.26848/rbgf.v13.3.p1309-1323.
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Os resíduos gerados no processo de calcinação dos calcários formam pilhas que se constituem em fontes de degradação do meio ambiente e obstáculos ao bom andamento das atividades das unidades produtoras. O aproveitamento desses rejeitos pode gerar benefícios ao meio ambiente, bem como melhorias ao trabalho dos operários, além de ser mais uma fonte de renda para as indústrias de calcinação locais. Este estudo foi desenvolvido no sentido do aproveitamento racional e econômico desses materiais residuais na pavimentação de estradas e na construção de obras de aterro que exijam solo estabilizado e, consequentemente, de boa consistência. Inicialmente, foram coletados resíduos de três províncias produtoras de cal na porção setentrional no estado do Ceará, sendo uma localizada entre os municípios de Coreaú e Sobral; outra em Forquilha; e uma terceira em Quixeré. As amostras foram misturadas com um solo argiloso, constituindo amostras compostas de solo-rejeito com proporções de resíduo de 0% (zero), 20, 30, 40, 50, 60, 70 e 80%. Ensaios geotécnicos foram realizados para determinação de suas granulometrias e respectivos índices de suporte Califórnia (CBR), de plasticidade (IP) e de grupo (IG). Como resultado, verificou-se aumento da resistência física do solo mediante a incorporação do rejeito nas amostras, constatando que um solo argiloso com características físicas não recomendadas para o uso na construção de estradas poderá se tornar útil para essa finalidade se estabilizado com os resíduos das indústrias de cal, promovendo a reparação de dano ambiental na área das unidades produtoras e uma destinação racional para os rejeitos. Use of tailings from the limestone calcination industries of the state of Ceará with a focus on repair of environmental damage A B S T R A C TThe residues generated in the limestone calcination process form piles sources of degradation of the environment and obstacles to the good progress of the activities of the producing units. The use of these tailings might generate benefits to the environment, as well as improvements to the job of the workers, besides being another source of income for the local calcination industries. This study was developed in the sense of the rational and economic use of these residual materials in the paving of roads and in the construction of landfills that require stabilized soil and, consequently, good consistency. Initially, waste was collected from three producing provinces of lime in Ceará, one of which is located between the municipalities of Coreaú and Sobral; another in Forquilha; and the third in Quixeré. The samples were mixed with a clay soil, consisting of soil-reject samples with residue ratios of 0% (zero), 20, 30, 40, 50, 60, 70 and 80%. Geotechnical tests were performed to determine their granulometry and respective California (CBR), plasticity (IP) and group (IG) indices. As result, soil physical strength increased by incorporating the reject in the samples, noting that a clay soil with physical characteristics not recommended for use in road construction could be useful for this purpose if stabilized with the residues of lime industries, promoting the environmental damage repair in the area of the producing units and a rational destination for the wastes.Keywords: paving; damage mitigation; environmental sustainability; lime.
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van der Zalm, Amber Perenna, Mark P. Dings, Reimer Janssen, Peter Bailey, Jan Koster, Danny Zwijnenburg, Richard Volckmann, et al. "Abstract 2616: Stemness factors nanog and oct4 contribute to epithelial-to-mesenchymal transition and are predictive for outcome in esophageal adenocarcinoma." Cancer Research 82, no. 12_Supplement (June 15, 2022): 2616. http://dx.doi.org/10.1158/1538-7445.am2022-2616.
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Abstract Background and Aims: The incidence of esophageal adenocarcinoma (EAC) has increased six-fold in Western countries over the last decades, and 5-year survival rates remain low at 5-20%. While multimodality treatment strategies for curative treatment of esophageal cancer, including the CROSS regimen (chemoradiotherapy followed by surgery) have increased median overall survival, the majority of patients develop recurrences after several months. Epithelial to mesenchymal transition (EMT) has been recently shown by our group to be one of the major underlying mechanisms of resistance to therapy. Paradoxically, therapeutic pressure of effective therapies such as the CROSS regimen are found to instruct a mesenchymal, resistant phenotype in models for EAC. In this study, the aim was to delineate the heterogeneity for the propensity to undergo EMT after chemoradiation and which mechanisms underpin this propensity. Methods: A panel of 8 EAC cell lines (5 primary and 3 ATCC cell lines) were treated with chemoradiotherapy and ranked by their propensity to undergo EMT, based on morphology when EMT occurred and protein marker expression. Next, the cell line panel as well as 44 pre-treated esophageal biopsies were RNA-sequenced. Expression data of the cell line panel were linked to their ranked in vitro EMT response. By means of Leave-one-out cross validation with Ridge Regression, EMT score prediction in pre-treated biopsies was validated. Gene expression profiles were related to clinical outcome data to identify markers that associated with propensity for EMT in patients. Results: In the panel of in vitro EAC models, a strong heterogeneity was observed for the propensity to EMT after chemoradiation. For each marker, Ridge regression analysis identified the top 50 highly correlating genes. Combining all positively correlating genes of days to EMT, NCAD and ZEB1, known key transcription factors of pluripotency including NANOG and OCT4 emerged. Expression of NANOG and OCT4 in pre-treatment biopsies was highly predictive for response to neoadjuvant chemoradiation, occurrence of recurrences, and survival in patients. Genetic perturbation by knockout and inhibition of NANOG and OCT4 reduced the onset of EMT and sensitized cells for chemoradiation. Conclusions: In conclusion, we were able to identify patients who are disproportionally prone to develop EMT in response to chemoradiation. Moreover, stemness factors NANOG and OCT4 are crucial regulators in plasticity of EAC and are promising predictive markers in pre-treatment biopsies of patients. By targeting NANOG and OCT4 in vitro, cells were sensitized to chemoradiation, holding promise for stemness inhibition to prevent therapy resistance in EAC. Citation Format: Amber Perenna van der Zalm, Mark P. Dings, Reimer Janssen, Peter Bailey, Jan Koster, Danny Zwijnenburg, Richard Volckmann, Cynthia Waasdorp, Jeroen Blokhuis, César Oyarce, Gerrit Hooijer, Sybren L. Meijer, Jan Paul Medema, Hanneke W. van Laarhoven, Maarten F. Bijlsma. Stemness factors nanog and oct4 contribute to epithelial-to-mesenchymal transition and are predictive for outcome in esophageal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2616.
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Kan, Zhengyan, Seock-Ah Im, Kyunghee Park, Ji Wen, Kyung-Hun Lee, Yoon-La Choi, Won-Chul Lee, et al. "Abstract PD2-08: Serial genomic profiling reveals molecular mechanisms of breast cancer resistance to palbociclib." Cancer Research 82, no. 4_Supplement (February 15, 2022): PD2–08—PD2–08. http://dx.doi.org/10.1158/1538-7445.sabcs21-pd2-08.
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Abstract CDK4/6 inhibitors such as palbociclib in combination with endocrine therapy (ET) have remarkablyimproved the outcome of patients with ER+/HER2- metastatic breast cancer (MBC). However, manypatients are intrinsically resistant to CDK4/6i therapy, and those who respond eventually acquireresistance. Although high baseline CCNE1 expression and rare alterations in RB1 and FAT1 geneshave been shown to be associated with CDK4/6i resistance, the molecular mechanisms of CDK4/6iresistance are complex and remain poorly understood. To better understand and overcome CDK4/6iresistance, we performed multi-omics profiling of paired tumor biopsies from ER+/HER2- MBCpatients treated with palbociclib combined with ET. Tumor biopsies taken at pre-treatment, on-treatment, and progressive disease (PD) from 71 patients were profiled using whole-exomesequencing (WES), whole-transcriptome sequencing (RNA-Seq) and IHC analysis. Ourcomprehensive analysis identified several tumor intrinsic molecular markers associated with worsePFS, including the Luminal B subtype (p=0.012, HR=2.593), BRCA1/2 pathogenic mutation (p=0.012,HR=2.67) and mutation signatures linked to APOBEC enzymatic activity (p=0.002, HR=3.19).Conversely, the estrogen response signature (p=0.006, HR=0.43) was associated with favorableprognosis. Unsupervised analysis revealed a cluster of tumors enriched in homologousrecombination deficiency (HRD) linked genomic scars that was associated with poor prognosis(p=0.005, HR=2.49). Of note, these HRD-high tumors responded even more poorly to treatment whenco-occurring with TP53 somatic mutations. Integrative analysis further identified three poorprognosis clusters (IC2-4) enriched in Luminal B, proliferative and HRD features when compared tothe favorable prognosis cluster (IC1).Comparing baseline vs. PD samples, we observed a pattern of post-treatment enrichment for the poorprognosis markers. In addition, breast cancer-associated genes such as BRCA1/2, TP53 and PTENharbored a higher prevalence of genomic alterations including somatic mutation, amplification,. deletion and gene fusion at PD. Cell cycle gene expression and signatures also markedly increased atPD compared to baseline whereas estrogen response signatures decreased. Upon diseaseprogression, tumors had frequently switched to molecular subtypes with aggressive and estrogenindependent characteristics, demonstrating high plasticity in response to CDK4/6i and ET treatment.These patterns of acquired resistance were validated by IHC analysis of cyclins E1 and E2, Ki67 andpRb. To investigate the genomic alterations responsible for acquired resistance, we compared 21paired baseline and PD samples. We observed that PD-specific RB1 loss-of-function events occurredwith higher prevalence than previously reported, underscoring a major role of cell cycle de-regulation in conferring resistance to CDK4/6 inhibition. In this prospective longitudinal multi-omicsstudy, we identified novel candidate biomarkers that can be used to improve prediction of responseto CDK4/6i. In addition, we derived new insights into the molecular mechanisms of drug resistanceto palbociclib plus ET that will help guide therapeutic strategies and drug development inHR+/HER2− MBC. Citation Format: Zhengyan Kan, Seock-Ah Im, Kyunghee Park, Ji Wen, Kyung-Hun Lee, Yoon-La Choi, Won-Chul Lee, Ahrum Min, Vinicius Bonato, Seri Park, Sripad Ram, Dae-Won Lee, Ji-Yeon Kim, Su Kyeong Lee, Won-Woo Lee, Jisook Lee, Miso Kim, Scott L. Weinrich, Han Suk Ryu, Tae Yong Kim, Stephen Dann, Diane Fernandez, Jiwon Koh, Song Yi Park, Shibing Deng, Eric Powell, Rupesh Kanchi Ravi, Jadwiga Bienkowska, Paul A. Rejto, Woong-Yang Park, Yeon Hee Park. Serial genomic profiling reveals molecular mechanisms of breast cancer resistance to palbociclib [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr PD2-08.
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Seebacher, Frank, and Alec I. M. Simmonds. "Histone deacetylase activity mediates thermal plasticity in zebrafish (Danio rerio)." Scientific Reports 9, no. 1 (June 3, 2019). http://dx.doi.org/10.1038/s41598-019-44726-x.
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Lewis, Victor M., Lauren M. Saunders, Tracy A. Larson, Emily J. Bain, Samantha L. Sturiale, Dvir Gur, Sarwat Chowdhury, et al. "Fate plasticity and reprogramming in genetically distinct populations of Danio leucophores." Proceedings of the National Academy of Sciences, May 28, 2019, 201901021. http://dx.doi.org/10.1073/pnas.1901021116.
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Understanding genetic and cellular bases of adult form remains a fundamental goal at the intersection of developmental and evolutionary biology. The skin pigment cells of vertebrates, derived from embryonic neural crest, are a useful system for elucidating mechanisms of fate specification, pattern formation, and how particular phenotypes impact organismal behavior and ecology. In a survey of Danio fishes, including the zebrafish Danio rerio, we identified two populations of white pigment cells—leucophores—one of which arises by transdifferentiation of adult melanophores and another of which develops from a yellow–orange xanthophore or xanthophore-like progenitor. Single-cell transcriptomic, mutational, chemical, and ultrastructural analyses of zebrafish leucophores revealed cell-type–specific chemical compositions, organelle configurations, and genetic requirements. At the organismal level, we identified distinct physiological responses of leucophores during environmental background matching, and we showed that leucophore complement influences behavior. Together, our studies reveal independently arisen pigment cell types and mechanisms of fate acquisition in zebrafish and illustrate how concerted analyses across hierarchical levels can provide insights into phenotypes and their evolution.
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Huang, Delai, Victor M. Lewis, Tarah N. Foster, Matthew B. Toomey, Joseph C. Corbo, and David M. Parichy. "Development and genetics of red coloration in the zebrafish relative Danio albolineatus." eLife 10 (August 26, 2021). http://dx.doi.org/10.7554/elife.70253.
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Animal pigment patterns play important roles in behavior and, in many species, red coloration serves as an honest signal of individual quality in mate choice. Among Danio fishes, some species develop erythrophores, pigment cells that contain red ketocarotenoids, whereas other species, like zebrafish (D. rerio) only have yellow xanthophores. Here, we use pearl danio (D. albolineatus) to assess the developmental origin of erythrophores and their mechanisms of differentiation. We show that erythrophores in the fin of D. albolineatus share a common progenitor with xanthophores and maintain plasticity in cell fate even after differentiation. We further identify the predominant ketocarotenoids that confer red coloration to erythrophores and use reverse genetics to pinpoint genes required for the differentiation and maintenance of these cells. Our analyses are a first step toward defining the mechanisms underlying the development of erythrophore-mediated red coloration in Danio and reveal striking parallels with the mechanism of red coloration in birds.
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Imai, Ana Paula, Thiago de Oliveira Abeche, and Roberto Dalledone Machado. "Damage and plasticity evolution of reinforced concrete beams using laminated Euler-Bernoulli finite elements." Revista IBRACON de Estruturas e Materiais 16, no. 5 (2023). http://dx.doi.org/10.1590/s1983-41952023000500002.
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abstract: This paper analyses the behaviour of reinforced concrete beams subjected to progressive loads. Although this topic is addressed in recent works through tri-dimensional finite elements, the present study adopts a simpler alternative, using Euler-Bernoulli’s beam finite element. The evolution of the generalized cracking is addressed by Damage Mechanics theory, and the nonlinear constitutive models of concrete and steel are considered, including plasticity and post-peak ‘. The laminated approach permits not only to ascertain the damage evolution but, in practical aspects, makes easy to define vertically symmetrical transversal sections and to distribute the reinforcement as desired, even if the steel rebars have different lengths. It is highlighted the changing of the neutral axis during the damage evolution process, which is updated automatically by the developed numeric-computational code. To validate the proposed methodology, two examples are detailed, both based on experimental tests found in the literature. The results obtained are close to the experimental ones and confirm the applicability of the proposed approach.
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Massey, Melanie D., M. Kate Fredericks, David Malloy, Suchinta Arif, and Jeffrey A. Hutchings. "Differential reproductive plasticity under thermal variability in a freshwater fish ( Danio rerio )." Proceedings of the Royal Society B: Biological Sciences 289, no. 1982 (September 7, 2022). http://dx.doi.org/10.1098/rspb.2022.0751.
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Human-driven increases in global mean temperatures are associated with concomitant increases in thermal variability. Yet, few studies have explored the impacts of thermal variability on fitness-related traits, limiting our ability to predict how organisms will respond to dynamic thermal changes. Among the myriad organismal responses to thermal variability, one of the most proximate to fitness—and, thus, a population's ability to persist—is reproduction. Here, we examine how a model freshwater fish ( Danio rerio ) responds to diel thermal fluctuations that span the species's viable developmental range of temperatures. We specifically investigate reproductive performance metrics including spawning success, fecundity, egg provisioning and sperm concentration. Notably, we apply thermal variability treatments during two ontogenetic timepoints to disentangle the relative effects of developmental plasticity and reversible acclimation. We found evidence of direct, negative effects of thermal variability during later ontogenetic stages on reproductive performance metrics. We also found complex interactive effects of early and late-life exposure to thermal variability, with evidence of beneficial acclimation of spawning success and modification of the relationship between fecundity and egg provisioning. Our findings illuminate the plastic life-history modifications that fish may undergo as their thermal environments become increasingly variable.
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Martini, Arianna, Ann Huysseune, Paul Eckhard Witten, and Clara Boglione. "Plasticity of the skeleton and skeletal deformities in zebrafish ( Danio rerio ) linked to rearing density." Journal of Fish Biology, February 19, 2020. http://dx.doi.org/10.1111/jfb.14272.
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Hosseini, Shahrbanou, Ngoc-Thuy Ha, Henner Simianer, Clemens Falker-Gieske, Bertram Brenig, Andre Franke, Gabriele Hörstgen-Schwark, Jens Tetens, Sebastian Herzog, and Ahmad Reza Sharifi. "Genetic mechanism underlying sexual plasticity and its association with colour patterning in zebrafish (Danio rerio)." BMC Genomics 20, no. 1 (May 6, 2019). http://dx.doi.org/10.1186/s12864-019-5722-1.
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Loughland, Isabella, Alexander Little, and Frank Seebacher. "DNA methyltransferase 3a mediates developmental thermal plasticity." BMC Biology 19, no. 1 (January 21, 2021). http://dx.doi.org/10.1186/s12915-020-00942-w.
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Abstract Background Thermal plasticity is pivotal for evolution in changing climates and in mediating resilience to its potentially negative effects. The efficacy to respond to environmental change depends on underlying mechanisms. DNA methylation induced by DNA methyltransferase 3 enzymes in the germline or during early embryonic development may be correlated with responses to environmental change. This developmental plasticity can interact with reversible acclimation within adult organisms, which would increase the speed of response and could alleviate potential mismatches between parental or early embryonic environments and those experienced at later life stages. Our aim was to determine whether there is a causative relationship between DNMT3 enzyme and developmental thermal plasticity and whether either or both interact with short-term acclimation to alter fitness and thermal responses in zebrafish (Danio rerio). Results We developed a novel DNMT3a knock-out model to show that sequential knock-out of DNA methyltransferase 3a isoforms (DNMT3aa−/− and DNMT3aa−/−ab−/−) additively decreased survival and increased deformities when cold developmental temperatures in zebrafish offspring mismatched warm temperatures experienced by parents. Interestingly, short-term cold acclimation of parents before breeding rescued DNMT3a knock-out offspring by restoring survival at cold temperatures. DNMT3a knock-out genotype interacted with developmental temperatures to modify thermal performance curves in offspring, where at least one DNMT3a isoform was necessary to buffer locomotion from increasing temperatures. The thermal sensitivity of citrate synthase activity, an indicator of mitochondrial density, was less severely affected by DNMT3a knock-out, but there was nonetheless a significant interaction between genotype and developmental temperatures. Conclusions Our results show that DNMT3a regulates developmental thermal plasticity and that the phenotypic effects of different DNMT3a isoforms are additive. However, DNMT3a interacts with other mechanisms, such as histone (de)acetylation, induced during short-term acclimation to buffer phenotypes from environmental change. Interactions between these mechanisms make phenotypic compensation for climate change more efficient and make it less likely that thermal plasticity incurs a cost resulting from environmental mismatches.
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Dunlap, Kent D., Magda C. Teles, and Rui F. Oliveira. "Social stimuli increase activity of adult-born cells in the telencephalon of zebrafish (Danio rerio)." Journal of Experimental Biology 224, no. 16 (August 15, 2021). http://dx.doi.org/10.1242/jeb.242253.
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ABSTRACT Fish have particularly high levels of adult neurogenesis, and this high neurogenic capacity may contribute to behavioural plasticity. While it is known that adult-born cells can differentiate into neurons and incorporate into neural circuits, it is unclear whether they are responsive to external stimuli and are thereby capable of contributing to behavioural change. We tested whether cells born in the telencephalon of adult zebrafish are activated by social stimuli. We marked cell birth with BrdU and, 40 days later, exposed fish to brief (15 min) visual social stimuli and assayed cellular activity through immunolocalization of phospho-S6-ribosomal protein (pS6). BrdU+/pS6+ co-labelled cells were found in six brain regions, and, in four regions [dorsal (D), dorsomedial (Dm) and dorsolateral (Dl) zones of the dorsal telencephalon and pre-optic area (POA)], the number of co-labelled cells and fraction of BrdU+ cells that labelled positive for pS6 increased during social stimulation. These results are consistent with the hypothesis that adult-born neurons play a role in regulating social behaviour.
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Wisenden, Brian D., Daniel C. Paulson, and Megan Orr. "Zebrafish embryos hatch early in response to chemical and mechanical indicators of predation risk, resulting in under-developed swimming ability of hatchling larvae." Biology Open, October 31, 2022. http://dx.doi.org/10.1242/bio.059229.
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Plasticity in hatching time allows embryos to maximize fitness by balancing benefits and costs of remaining bound within the chorion against the benefits and costs of emerging as a free-swimming larva. In our first experiment, we exposed zebrafish (Danio rerio) embryos to either chemical cues from crushed embryos (simulating egg predation) or to blank water control. Embryos exposed to alarm cues hatched sooner with shorter body lengths and underdeveloped fins relative to larvae from the water treatment. Burst swimming speed was significantly slower for larvae that hatched from the alarm cue treatment. In a second 2 x 2 experiment, we exposed zebrafish embryos to either chemical alarm cues from conspecific embryos, mechanical disturbance (magnetic stir bar) to simulate a predator probing the substrate for developing embryos, both chemical and mechanical indicators of risk, or neither (control). We found similar effects in terms of earlier time to hatch at an earlier stage of development and poorer swimming performance of hatchling larvae. In the second experiment these effects occurred in response to mechanical disturbance with or without the presence of chemical alarm cues. Alarm cues alone produced no effects in the second experiment. Taken together, these data indicate that zebrafish embryos demonstrate a facultative tradeoff between risk of predation acting on two stages of their life history.
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Vigorito, Carmela, Eugenia Anishchenko, Annapaola Coppola, Patrizia Lombari, Diego Ingrosso, and Alessandra Perna. "P0095MOLECULAR MECHANISMS OF THE CARDIOVASCULAR EFFECTS OF LANTHIONINE, A NEW UREMIC TOXIN, AND ITS INTERACTIONS WITH THE REDOX MICROENVIRONMENT." Nephrology Dialysis Transplantation 35, Supplement_3 (June 1, 2020). http://dx.doi.org/10.1093/ndt/gfaa142.p0095.
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Abstract Background and Aims The non-proteinogenic amino acid lanthionine is a byproduct of the biosynthesis of hydrogen sulfide (H2S), an endogenously produced gas with cardiovascular properties). Lanthionine concentration is increased in uremia and it has been proposed as a new uremic toxin. In the zebrafish model, lanthionine induces effects on cardiac embriogenesis, arrhythmia, and locomotor alterations. Some effects are counteracted by glutathione, the well known antioxidant. In a human endothelial cell model, lanthionine significantly reduces H2S release, both protein content and glutathionylation of cystathione beta-synthase (CBS), one of the main H2S-producing enzymes, miR-200c and miR-423 levels, as well as vascular endothelial growth factor expression, while it also increases intracellular calcium levels. We investigated in the present abstract the actions of glutathione on some of lanthionine effects on zebrafish and endothelial cells. We utilized what is considered to be a more stable form of glutathione, acetylglutathione (AcGSH). Method Zebrafish behavior and heart size were analyzed by the Danio Vision system and confocal microscopy, respectively. Gene and protein expression were analyzed usimg qPCR and Western Blot, respectively. CBS glutathionylation has been assessed by immunoprecipitation with a magnetic beads-coated anti-GSH. Interleukins levels were evaluated by ELISA. Lanthionine acetylation was evaluated by LC/MS. Results In zebrafish, we demonstrated that AcGSH significantly increases heart size and the expression of atrium specific proteins. Increased heart rate and heart rhythm plasticity determined by AcGSH were partially counteracted by lanthionine. Monitoring of larval movements showed that this behavior was affected by AcGSH supplementation. In endothelial cells, AcGSH increased H2S release, and, utilized in combination with lanthionine, it was able to partially counteract its effects on H2S release. AcGSH was able to increase CBS glutathionylation and to offset lanthionine effects on glutathionylation. In addition, it increased tubulin, histone, and NFKB acetylation and IL-8 and IL-13 levels. We also demonstrated with mass spectrometry that lanthionine was non-enzymatically acetylated by AcGSH, suggesting a possible mechanism. Conclusion In conclusion, our findings support the notion that lanthionine is a uremic toxin, which is strongly modified in its effects by the redox microenvironment.