ORCID Profile
0000-0002-7090-9266
Current Organisation
University of California, San Diego
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Publisher: Wiley
Date: 06-06-2022
Abstract: The coral‐algal symbiosis is the biological engine that drives one of the most spectacular structures on Earth: the coral reef. Here, living coral microhabitats are engineered using 3D bioprinting, as biomimetic model system of the coral‐algal symbiosis. Various bioinks for the encapsulation of coral photosymbiotic microalgae ( Breviolum psygmophilum ) are developed and coral mass transfer phenomena are mimicked by 3D bioprinting coral tissue and skeleton microscale features. At the tissue–seawater interface, the biomimetic coral polyp and connective tissue structures successfully replicate the natural build‐up of the O 2 diffusive boundary layer. Inside the bioprinted construct, coral‐like microscale gastric cavities are engineered using a multi‐material bioprinting process. Underneath the tissue, the constructs mimic the porous architecture of the coral aragonite skeleton at the micrometer scale, which can be manipulated to assess the effects of skeletal architecture on stress‐related hydrogen peroxide (H 2 O 2 ) production. The bioprinted living coral microhabitats replicate the diffusion‐related phenomena that underlie the functioning and breakdown of the coral‐algal symbiosis and can be exploited for the additive manufacturing of synthetic designer corals.
Publisher: Wiley
Date: 25-10-2020
Publisher: The Company of Biologists
Date: 15-01-2005
DOI: 10.1242/JEB.01382
Abstract: To study the mechanisms of branchial acid-base regulation, Pacific spiny dogfish were infused intravenously for 24 h with either HCl (495± 79μmol kg-1 h-1) or NaHCO3 (981±235μmol kg-1 h-1). Infusion of HCl produced a transient reduction in blood pH. Despite continued infusion of acid, pH returned to normal by 12 h. Infusion of NaHCO3 resulted in a new steady-state acid-base status at ∼0.3 pH units higher than the controls. Immunostained serial sections of gill revealed the presence of separate vacuolar proton ATPase (V-H+-ATPase)-rich or sodium-potassium ATPase(Na+/K+-ATPase)-rich cells in all fish examined. A minority of the cells also labeled positive for both transporters. Gill cell membranes prepared from NaHCO3-infused fish showed significant increases in both V-H+-ATPase abundance (300±81%) and activity. In addition, we found that V-H+-ATPase subcellular localization was mainly cytoplasmic in control and HCl-infused fish, while NaHCO3-infused fish demonstrated a distinctly basolateral staining pattern. Western analysis in gill membranes from HCl-infused fish also revealed increased abundance of Na+/H+ exchanger 2(213±5%) and Na+/K+-ATPase (315±88%)compared to the control.
Publisher: eLife Sciences Publications, Ltd
Date: 28-07-2020
Publisher: Cold Spring Harbor Laboratory
Date: 28-05-2022
DOI: 10.1101/2022.05.26.493626
Abstract: Diatoms, dinoflagellates, and coccolithophorids are the dominant groups of marine eukaryotic phytoplankton collectively responsible for the majority of primary production in the ocean 1 . These phytoplankton contain additional intracellular membranes around their chloroplasts derived from ancestral engulfment of red microalgae by unicellular heterotrophic eukaryotes that led to secondary endosymbiosis 2 . This symbiogenesis hypothesis for the origin of modern secondary endosymbiotic phytoplankton is supported by a wealth of palaeontologic, morphologic, and genomic evidence 3–6 . However, the selectable evolutionary advantage of these membranes and the physiological significance for extant phytoplankton are unknown. We report that the proton-pumping enzyme V-type H + -ATPase (VHA), ubiquitously used in eukaryotic intercellular digestion, is localized around the chloroplasts of centric diatoms and that VHA-activity significantly enhances photosynthesis over a wide range of oceanic irradiances. Similar results in pennate diatoms, dinoflagellates, and coccolithophorids, but not green or red microalgae, imply a mechanism resulting from the co-option of phagocytic VHA activity into a carbon concentrating mechanism that is common to secondary endosymbiotic phytoplankton. Furthermore, analogous VHA-dependent mechanisms in extant photosymbiotic marine invertebrates 7–9 provide functional evidence for an adaptive advantage throughout the transition from endosymbiosis to symbiogenesis. Our results suggest that VHA-dependent enhancement of photosynthesis contributes at least 7% of primary production in the ocean, providing an ex le of a symbiosis-derived evolutionary innovation with global environmental implications.
Publisher: The Royal Society
Date: 07-2017
Abstract: Object recognition memory is the ability to identify previously seen objects and is an adaptive mechanism that increases survival for many species throughout the animal kingdom. Previously believed to be possessed by only the highest order mammals, it is now becoming clear that fish are also capable of this type of memory formation. Similar to the mammalian hippoc us, the dorsolateral pallium regulates distinct memory processes and is modulated by neurotransmitters such as dopamine. Caribbean bicolour damselfish ( Stegastes partitus ) live in complex environments dominated by coral reef structures and thus likely possess many types of complex memory abilities including object recognition. This study used a novel object recognition test in which fish were first presented two identical objects, then after a retention interval of 10 min with no objects, the fish were presented with a novel object and one of the objects they had previously encountered in the first trial. We demonstrate that the dopamine D 1 -receptor agonist (SKF 38393) induces the formation of object recognition memories in these fish. Thus, our results suggest that dopamine-receptor mediated enhancement of spatial memory formation in fish represents an evolutionarily conserved mechanism in vertebrates.
Publisher: Wiley
Date: 20-12-2019
DOI: 10.1002/LOL2.10129
Abstract: Coral reefs are facing intensifying stressors, largely due to global increases in seawater temperature and decreases in pH. However, there is extensive environmental variability within coral reef ecosystems, which can impact how organisms respond to global trends. We deployed spatial arrays of autonomous sensors across distinct shallow coral reef habitats to determine patterns of spatiotemporal variability in seawater physicochemical parameters. Temperature and pH were positively correlated over the course of a day due to solar heating and light‐driven metabolism. The mean temporal and spatial ranges of temperature and pH were positively correlated across all sites, with different regimes of variability observed in different reef types. Ultimately, depth was a reliable predictor of the average diel ranges in both seawater temperature and pH. These results demonstrate that there is widespread environmental variability on diel timescales within coral reefs related to water column depth, which needs to be included in assessments of how global change will locally affect reef ecosystems.
Publisher: Springer Science and Business Media LLC
Date: 16-03-2023
Publisher: Elsevier BV
Date: 06-2023
Publisher: The Royal Society
Date: 02-2022
Abstract: Puffer and porcupine fishes (families Diodontidae and Tetraodontidae, order Tetradontiformes) are known for their extraordinary ability to triple their body size by swallowing and retaining large amounts of seawater in their accommodating stomachs. This inflation mechanism provides a defence to predation however, it is associated with the secondary loss of the stomach's digestive function. Ingestion of alkaline seawater during inflation would make acidification inefficient (a potential driver for the loss of gastric digestion), paralleled by the loss of acid–peptic genes. We tested the hypothesis of stomach inflation as a driver for the convergent evolution of stomach loss by investigating the gastric phenotype and genotype of four distantly related stomach inflating gnathostomes: sargassum fish, swellshark, bearded goby and the pygmy leatherjacket. Strikingly, unlike in the puffer orcupine fishes, we found no evidence for the loss of stomach function in sargassum fish, swellshark and bearded goby. Only the pygmy leatherjacket (Monochanthidae, Tetraodontiformes) lacked the gastric phenotype and genotype. In conclusion, ingestion of seawater for inflation, associated with loss of gastric acid secretion, is restricted to the Tetraodontiformes and is not a selective pressure for gastric loss in other reported gastric inflating fishes.
Publisher: eLife Sciences Publications, Ltd
Date: 25-08-2020
DOI: 10.7554/ELIFE.58995
Abstract: Previously, we showed that the evolution of high acuity vision in fishes was directly associated with their unique pH-sensitive hemoglobins that allow O 2 to be delivered to the retina at PO 2 s more than ten-fold that of arterial blood (Damsgaard et al., 2019). Here, we show strong evidence that vacuolar-type H + -ATPase and plasma-accessible carbonic anhydrase in the vascular structure supplying the retina act together to acidify the red blood cell leading to O 2 secretion. In vivo data indicate that this pathway primarily affects the oxygenation of the inner retina involved in signal processing and transduction, and that the evolution of this pathway was tightly associated with the morphological expansion of the inner retina. We conclude that this mechanism for retinal oxygenation played a vital role in the adaptive evolution of vision in teleost fishes.
Publisher: Wiley
Date: 05-04-2021
DOI: 10.1002/JEZ.2456
Abstract: The obligate air‐breathing Amazonian fish, Arapaima gigas , hatch as water‐breathing larvae but with development, they modify their swim bladder to an air‐breathing organ (ABO) while reducing their gill filaments to avoid oxygen loss. Here, we show that significant changes already take place between 4 weeks (1.6 g) and 11 weeks (5 g) post hatch, with a reduction in gill lamellar surface area, increase in gill diffusion distance, and proliferation of the parenchyma in the ABO. By using a variety of methods, we quantified the surface area and diffusion distances of the gills and skin, and the swim bladder volume and anatomical complexity from hatch to 11‐week‐old juveniles. In addition, we identified the presence of two ionocyte types in the gills and show how these change with development. Until 1.6 g, A. gigas possess only the H + ‐excreting/Na + ‐absorbing type, while 5‐g fish and adults have an additional ionocyte which likely absorbs H + and Cl − and excretes HCO 3 − . The ionocyte density on the gill filaments increased with age and is likely a compensatory mechanism for maintaining ion transport while reducing gill surface area. In the transition from water‐ to air‐breathing, A. gigas likely employs a trimodal respiration utilizing gills, skin, and ABO and thus avoid a respiratory–ion regulatory compromise at the gills.
Location: United States of America
No related grants have been discovered for Martin Tresguerres.