Search results for "Fish"
showing 10 items of 3164 documents
Data from: The strategic reference gene: an organismal theory of inclusive fitness
2019
How to define and use the concept of inclusive fitness is a contentious topic in evolutionary theory. Inclusive fitness can be used to calculate selection on a focal gene, but it is also applied to whole organisms. Individuals are then predicted to appear designed as if to maximise their inclusive fitness, provided that certain conditions are met (formally when interactions between individuals are ‘additive’). Here we argue that applying the concept of inclusive fitness to organisms is justified under far broader conditions than previously shown, but only if it is appropriately defined. Specifically, we propose that organisms should maximise the sum of their offspring (including any accrued…
Ion conductance changes associated with spike adaptation in the rapidly adapting stretch receptor of the crayfish.
1975
The time course of the repetitive impulse discharges has been investigated for two high intensities of maintained depolarizing currents, 30 nA and 50 nA, for which the receptor adaptation was complete within 70 msec. The changes in sodium and potassium conductance associated with the decline in spike activity have been analyzed at different instances of time by interrupting in successive experiments the various action potentials in the pulse trains either at the early phase by holding the potential at about -60 mV and recording the inward current (upstroke-gNa) or by evaluating the delayed outward current flowing as the result of a depolarizing voltage pulse which at the end of the action p…
A novel moniliformin derivative as pan-inhibitor of histone deacetylases triggering apoptosis of leukemia cells
2021
New and potent agents that evade multidrug resistance (MDR) and inhibit epigenetic modifications are of great interest in cancer drug development. Here, we describe that a moniliformin derivative (IUPAC name: 3-(naphthalen-2-ylsulfanyl)-4-{[(2Z)-1,3,3-trimethyl-2,3-dihydro-1H-indol-2-ylidene]methyl}cyclobut-3-ene-1,2-dione; code: MCC1381) bypasses P-gp-mediated MDR. Using transcriptomics, we identified a large number of genes significantly regulated in response to MCC1381, which affected the cell cycle and disturbed cellular death and survival. The potential targets of MCC1381 might be histone deacetylases (HDACs) as predicted by SwissTargetPrediction. In silico studies confirmed that MCC13…
Ontogenetic development of the holocephalan dentition: Morphological transitions of dentine in the absence of teeth.
2021
Among the cartilaginous fishes (Chondrichthyes), the Holocephali are unique in that teeth are absent both in ontogeny and adult regenerative growth. Instead, the holocephalan dentition of ever-growing nonshedding dental plates is composed of dentine, trabecular in arrangement, forming spaces into which a novel hypermineralized dentine (whitlockin) is deposited. These tissue features form a variety of specific morphologies as the defining characters of dental plates in the three families of extant holocephalans. We demonstrate how this morphology changes through ontogenetic development with continuity between morphologies, through successive growth stages of the dentition represented by the …
In vivo Imaging of Fully Active Brain Tissue in Awake Zebrafish Larvae and Juveniles by Skull and Skin Removal.
2021
Understanding the ephemeral changes that occur during brain development and maturation requires detailed high-resolution imaging in space and time at cellular and subcellular resolution. Advances in molecular and imaging technologies have allowed us to gain numerous detailed insights into cellular and molecular mechanisms of brain development in the transparent zebrafish embryo. Recently, processes of refinement of neuronal connectivity that occur at later larval stages several weeks after fertilization, which are for example control of social behavior, decision making or motivation-driven behavior, have moved into focus of research. At these stages, pigmentation of the zebrafish skin inter…
Dracunculiasis: water-borne anthroponosis vs. food-borne zoonosis.
2019
Abstract Dracunculiasis is the first parasitic disease set for eradication. However, recent events related to the Dracunculus medinensis epidemiology in certain African countries are apparently posing new challenges to its eradication. Two novel facts have emerged: the existence of animal reservoirs (mainly dogs but also cats and baboons), and possibly a new food-borne route of transmission by the ingestion of paratenic (frogs) or transport (fish) hosts. Therefore, instead of being exclusively a water-borne anthroponosis, dracunculiasis would also be a food-borne zoonosis. The existence of a large number of infected dogs, mainly in Chad, and the low number of infected humans, have given ris…
Inferring fish abundance in lakes from subfossil midge (Diptera:Chironomidae) remains
2017
This study assessed the possibility of using subfossil remains of chironomid head capsules to reconstruct past fish abundances in lakes. Using data from 20 Swedish lakes, a weighted average (WA) model was created to predict the abundance of benthivorous fish (cyprinids and perch). Chironomid head capsules, identified to genus, served as the predictors to model already recorded (catch per unit effort) fish data. The relationship of chironomid species composition to lake morphometry, water chemistry and fish abundance were examined using ordination and variation partitioning methods. Moreover, the relationship between fish abundance and two chironomid species traits: body size and activity mo…
Development and validation of a pressurized liquid extraction liquid chromatography–tandem mass spectrometry method for perfluorinated compounds dete…
2009
Abstract This paper describes the development and validation of an analytical methodology to determine eight perfluorinated compounds (PFCs) in edible fish using pressurized liquid extraction (PLE) with water and solid-phase extraction (SPE) with an ion-exchanger as extraction and pre-concentration procedures, followed by liquid chromatography–quadrupole-linear ion trap mass spectrometry (LC–QqLIT–MS). The rapidity and effectiveness of the proposed extraction procedure were compared with those most commonly used to isolate PFCs from fish (ion-pairing and alkaline digestion). The average recoveries of the different fish samples, spiked with the eight PFCs at three levels (the LOQ, 10 and 100…
Recovery of Bioactive Compounds from Marine Organisms: Focus on the Future Perspectives for Pharmacological, Biomedical and Regenerative Medicine App…
2023
Marine environments cover more than 70% of the Earth’s surface and are among the richest and most complex ecosystems. In terms of biodiversity, the ocean represents an important source, still not widely exploited, of bioactive products derived from species of bacteria, plants, and animals. However, global warming, in combination with multiple anthropogenic practices, represents a serious environmental problem that has led to an increase in gelatinous zooplankton, a phenomenon referred to as jellyfish bloom. In recent years, the idea of “sustainable development” has emerged as one of the essential elements of green-economy initiatives; therefore, the marine environment has been re-evaluated …
Ring diameter effects on determination of field-saturated hydraulic conductivity of different loam soils
2017
Abstract Establishing ring diameter effects on the field-saturated soil hydraulic conductivity, Kfs, determined with ponding infiltrometer methods can help to find a compromise between the need to sample a large area with an individual measurement and the impracticality of using large rings in the field. Five ring sizes (diameter, D = 5.5, 10.9, 16.0, 27.8 and 31.8 cm) were used to determine Kfs by the simplified falling head (SFH) technique in four loamy soils with different salinity (electrical conductivity of saturated extract, ECe = 0.9–29.4 dS/m) and sodicity (exchangeable sodium percentage, ESP = 2.7–81.3%) levels. According to USDA classification, two soils were non-saline, non-sodic…