Results 131 to 140 of about 84,077 (281)
Abstract The Amazonian loricariid fish Pterygoplichthys gibbiceps, from the Rio Negro, and Pterygoplichthys pardalis, from the Rio Solimões, are facultative air‐breathers that can use the stomach as an air‐breathing organ. Measurement of oxygen uptake under progressive aquatic hypoxia revealed a relatively high hypoxia resistance of both species.
Bernd Pelster +2 more
wiley +1 more source
Nitrogen excretion and oxygen consumption under severe hypoxia in siluriform fishes from the Amazon
Abstract Siluriform fishes collected from the Rio Negro and Rio Solimões proved to be highly resistant to aquatic hypoxia. In all four species analysed in this study, aquatic oxygen consumption significantly decreased from normoxic levels at water PO2 values near 1 kPa. Air‐breathing activity was observed only in Sturisoma sp. (Rio Negro).
Bernd Pelster +2 more
wiley +1 more source
the structural and ultrastructural features of gonads from endemic Mexican fish have received scarce attention. This study describes the histological and ultrastructural characteristics of the oocyte in Chirostoma humboldtianum. The ovary is asynchronic,
Rodolfo Cárdenas +5 more
doaj
Abstract Fewer than 50 of the over 30,000 extant species of fishes have developed anatomical specializations facilitating endothermy in specific body regions. The plankton‐feeding basking shark (Cetorhinus maximus), traditionally classified as an ectotherm, was recently shown to have regionally endothermic traits such as centralized red muscle (RM ...
C. Antonia Klöcker +9 more
wiley +1 more source
Mercury (Hg) pro-oxidant role on biological systems and its biogeochemical cycle represent a serious threat due to its persistence in marine environment.
Marta Giuga +6 more
doaj +1 more source
Pinopsin Regulates Melatonin Production and Daily Locomotor Activity: Functional Insights From Gene-Edited Xenopus Tadpoles. [PDF]
ABSTRACT Circadian rhythm alignment depends on environmental light detection via opsins. Pinopsin, originally identified in the pineal organ of birds and later in amphibian pineal complex and eyes, may play a role in this process, though its function has not been genetically tested.
Heshami N +4 more
europepmc +2 more sources
Abstract The branchial epithelium of Potamotrygon—a member of the only strictly freshwater elasmobranch family Potamotrygonidae—was observed via immunohistochemistry, and two distinct forms of ionocytes were identified. The acid (A‐type) and base (B‐type) secreting cells with respective basolateral–apical localizations of Na+/K+‐ATPase–Na+/H+ exchanger
M. W. Rossi +3 more
wiley +1 more source
Abstract Sexual maturation of male Atlantic salmon post‐smolts (‘jacking’) is undesired in aquaculture and seems to occur due to the intensification in modern facilities. Maturation depends on internal and external factors (temperature, photoperiod, feed availability, energy levels, body size, genetic background) that act on the brain‐pituitary‐gonad ...
Enrique Pino‐Martinez +5 more
wiley +1 more source
Newly discovered and conserved role of IgM against viral infection in an early vertebrate
IgM emerged in jawed vertebrates 500 Mya and remains the most evolutionarily conserved antibody class. However, despite extensive studies on IgM as an ancient antiviral weapon in warm-blooded vertebrates, its role and mechanisms in combating viral ...
Weiguang Kong +9 more
doaj +1 more source
Abstract In teleost fishes, cortisol is the major corticoid and has both glucocorticoid and mineralocorticoid actions. However, how fish tissues discriminate between these distinct corticosteroid actions is unclear. In mammals, the major factors responsible for intracellular corticosteroid regulation are glucocorticoid receptors (grs) and the ...
Makoto Kusakabe +4 more
wiley +1 more source

