The effects of salinity on growth, gill tissue and muscle cellularity in Lophiosilurus alexandri juvenile, a Neotropical freshwater catfish

2021 ◽  
Author(s):  
Rodrigo Takata ◽  
Cristiano Campos Mattioli ◽  
Nilo Bazzoli ◽  
José Dias Corrêa Júnior ◽  
Ronald Kennedy Luz
2020 ◽  
Vol 644 ◽  
pp. 91-103
Author(s):  
D Bearham ◽  
MA Vanderklift ◽  
RA Downie ◽  
DP Thomson ◽  
LA Clementson

Benthic suspension feeders, such as bivalves, potentially have several different food sources, including plankton and resuspended detritus of benthic origin. We hypothesised that suspension feeders are likely to feed on detritus if it is present. This inference would be further strengthened if there was a correlation between δ13C of suspension feeder tissue and δ13C of particulate organic matter (POM). Since detritus is characterised by high particulate organic matter (POC):chl a ratios, we would also predict a positive correlation between POM δ13C and POC:chl a. We hypothesised that increasing depth and greater distance from shore would produce a greater nutritional reliance by experimentally transplanted blue mussels Mytilus edulis on plankton rather than macrophyte-derived detritus. After deployments of 3 mo duration in 2 different years at depths from 3 to 40 m, M. edulis sizes were positively correlated with POM concentrations. POC:chl a ratios and δ13C of POM and M. edulis gill tissue decreased with increasing depth (and greater distance from shore). δ13C of POM was correlated with δ13C of M. edulis. Our results suggest that detritus comprised a large proportion of POM at shallow depths (<15 m), that M. edulis ingested and assimilated carbon in proportion to its availability in POM, and that growth of M. edulis was higher where detritus was present and POM concentrations were higher.


Author(s):  
AH Klein ◽  
CA Motti ◽  
AK Hillberg ◽  
T Ventura ◽  
P Thomas-Hall ◽  
...  

AbstractGastropod molluscs are among the most abundant species that inhabit coral reef ecosystems. Many are specialist predators, along with the giant triton snail Charonia tritonis (Linnaeus, 1758) whose diet consists of Acanthaster planci (crown-of-thorns starfish), a corallivore known to consume enormous quantities of reef-building coral. C. tritonis are considered vulnerable due to overexploitation, and a decline in their populations is believed to have contributed to recurring A. planci population outbreaks. Aquaculture is considered one approach that could help restore natural populations of C. tritonis and mitigate coral loss; however, numerous questions remain unanswered regarding their life cycle, including the molecular factors that regulate their reproduction and development. In this study, we have established a reference C. tritonis transcriptome derived from developmental stages (embryo and veliger) and adult tissues. This was used to identify genes associated with cell signalling, such as neuropeptides and G protein-coupled receptors (GPCRs), involved in endocrine and olfactory signalling. A comparison of developmental stages showed that several neuropeptide precursors are exclusively expressed in post-hatch veligers and functional analysis found that FFamide stimulated a significant (20.3%) increase in larval heart rate. GPCRs unique to veligers, and a diversity of rhodopsin-like GPCRs located within adult cephalic tentacles, all represent candidate olfactory receptors. In addition, the cytochrome P450 superfamily, which participates in the biosynthesis and degradation of steroid hormones and lipids, was also found to be expanded with at least 91 genes annotated, mostly in gill tissue. These findings further progress our understanding of C. tritonis with possible application in developing aquaculture methods.


Toxicon ◽  
2015 ◽  
Vol 101 ◽  
pp. 55-62 ◽  
Author(s):  
Beatriz Elena Sarmiento ◽  
Marisa Rangel ◽  
Jacqueline Coimbra Gonçalves ◽  
Lilibete Pereira ◽  
Solange Rego ◽  
...  

Marine Drugs ◽  
2021 ◽  
Vol 19 (5) ◽  
pp. 276
Author(s):  
Mariaelena D’Ambrosio ◽  
Cátia Gonçalves ◽  
Mariana Calmão ◽  
Maria Rodrigues ◽  
Pedro M. Costa

Marine biodiversity has been yielding promising novel bioproducts from venomous animals. Despite the auspices of conotoxins, which originated the paradigmatic painkiller Prialt, the biotechnological potential of gastropod venoms remains to be explored. Marine bioprospecting is expanding towards temperate species like the dogwhelk Nucella lapillus, which is suspected to secrete immobilizing agents through its salivary glands with a relaxing effect on the musculature of its preferential prey, Mytilus sp. This work focused on detecting, localizing, and testing the bioreactivity of cysteine-rich proteins and peptides, whose presence is a signature of animal venoms and poisons. The highest content of thiols was found in crude protein extracts from the digestive gland, which is associated with digestion, followed by the peribuccal mass, where the salivary glands are located. Conversely, the foot and siphon (which the gastropod uses for feeding) are not the main organs involved in toxin secretion. Ex vivo bioassays with Mytilus gill tissue disclosed the differential bioreactivity of crude protein extracts. Secretions from the digestive gland and peribuccal mass caused the most significant molecular damage, with evidence for the induction of apoptosis. These early findings indicate that salivary glands are a promising target for the extraction and characterization of bioactive cysteine-rich proteinaceous toxins from the species.


2021 ◽  
Author(s):  
Angela Carolina Guillen ◽  
Marcelo Eduardo Borges ◽  
Tatiana Herrerias ◽  
Priscila Krebsbach Kandalski ◽  
Maria Rosa Dmengeon Pedreiro de Souza ◽  
...  

Abstract Antarctica is considered a thermally stable ecosystem; however, climate studies point to increases in air and surface water temperatures in this region. These thermal changes may affect the biological processes of animals inhabiting such regions because they are stress factors and may promote metabolic changes, rendering the animals more vulnerable to oxidative damage. Plasma parameters are also good indicators of stress and allow analysis of the metabolic status of fish under temperature increases. The present study assessed the effect of acclimation temperature on the levels of plasma, osmoregulatory and oxidative metabolism parameters and antioxidant defenses in kidney, gill, liver and brain tissues of Notothenia rossii subjected to gradual temperature changes of 0.5°C/day until reaching temperatures of 2, 4, 6 and 8°C. Under the effect of the 0.5°C/day acclimation rate, gill tissue showed increased glutathione-S-transferase (GST) activity, and kidney tissue showed increased H⁺-ATPase at 9 days of the experiment (2°C). In the liver, consistent increases in the MDA concentration as an indicator of lipid peroxidation (9 (2°C),13 (4°C),17 (6°C) and 21 (6°C) days) were noted, as well as an increase in GSH at 9 days (2°C). In plasma, gradual decreases in the concentrations of total proteins and globulins were observed. These responses indicate the presence of thermal plasticity and an attempt at regulation to mitigate thermal stress. The changes showed that a gradual increase in temperature may cause opposite responses to the thermal shock model in N. rossii.


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