Water Permeability of the Gill Epithelium: Salinity and Temperature Relations
Gheorghe Benga in Water Transport in Biological Membranes, 1989
It is now recognized that the complex structure of gills, in particular fish gills, does not allow for the treatment of water exchanges as diffusion across a homogeneous membrane. There may be functional separation of the gas and ion exchange areas in a gill. In fish, the osmoregulatory chloride cells are virtually restricted to the primary lamellae. There are functional differences between anterior and posterior gills in crabs, where ion-transporting cells (10 to 20 μm thick) are concentrated in patches on posterior gill pairs interspersed with the flattened respiratory cells (1 to 2 μm thick) common to every gill pair.33,34 The simple lamellar gills of amphipod crustaceans are composed of a single, multifunctional type of cell.35 The functional vascularization of the fish gill has now been described, allowing for separation of the fluxes across the respiratory and nonrespiratory epithelium,20 i.e., the secondary lamellae, representing the greater part (≃96%) of the exchange surface and the primary lamellae (≃4% of the exchange surface), respectively. It has been established for gill tissue exhibiting regional specialization of function that water exchanges occur principally through the respiratory cells. The branchial respiratory epithelium is composed of flat cells which in most cases are linked by deep intercellular junctions, and it is suggested that the cell membranes, rather than these tight junctions, are the limiting factor of branchial water permeability (i.e., water traverses the gill by a transcellular route).20
The Cell Biology of Amelogenesis
Colin Robinson, Jennifer Kirkham, Roger Shore in Dental Enamel, 2017
The microfilaments of cell webs may modulate tight junction permeability.131 It has been shown that cytochalasin B, a chemical that alters microfilaments, reduces junctional permeability in Necturus gallbladder.131 Additionally, the interaction of cAMP, intracellular Ca++, intercellular space pressure/volume, and transcellular transport also affect tight junction permeability.131 However, little else is known concerning anion translocation through epithelial cells, including ameloblasts. Recently, chloride transport through lung epithelial cells has been shown to occur through CI channels.132 In chloride cells of fish gill epithelium, CI- is translocated intracellularly to the external environment, while Na+ travels along a paracellular route.133 Anion channels are also known to be selectively permeable to all halogens, including fluoride.134 The possibility that secretory ameloblasts contain anion channels that are selectively permeable to fluoride is an important concept that needs further investigation.
Mercury disrupts redox status, up-regulates metallothionein and induces genotoxicity in respiratory tree of sea cucumber (Holothuria forskali)
Published in Drug and Chemical Toxicology, 2020
Khaoula Telahigue, Imen Rabeh, Safa Bejaoui, Tarek Hajji, Salwa Nechi, Emna Chelbi, M’hamed El Cafsi, Nejla Soudani
ROS are also believed to induce deleterious effects on proteins. From a molecular perspective, protein oxidation may lead to amino acid side chain modifications, protein cross-linking, protein backbone fragmentation and protein conformational changes (Lund and Baron 2010). Besides PCO, which is a reliable marker for ongoing protein oxidation (Breusing and Grune 2010), AOPP has been considered a novel marker of oxidant-mediated protein damage (Wu 2015). So far, no data are available regarding the effect of metals on protein oxidation in Holothurians. In the current study, the occurrence of proteins oxidative-related damage in the Hg-treated groups was evidenced by the increase in PCO and AOPP contents. Our findings suggested that loss of protein functions might be one of the most probable pathways of mercury toxicity mechanisms. Our results are in agreement with previous research which has demonstrated that mercury chloride enhanced protein oxidation in fish gill (Monteiro et al. 2010).
Histopathological changes and antioxidant responses in common carp (Cyprinus carpio) exposed to copper nanoparticles
Published in Drug and Chemical Toxicology, 2021
Aasma Noureen, Farhat Jabeen, Tanveer A. Tabish, Muhammad Ali, Rehana Iqbal, Sajid Yaqub, Abdul Shakoor Chaudhry
A completely randomized design was used to evenly distribute 120 fish (taken from stock aquaria) into twelve aerated glass tanks (10 fish/tank) where 3 tanks represented each of the 3 doses of Cu-NPs and one control group. Based on the LC50, three sub-lethal doses (0.5, 1, and 1.5 mg/l represented by Cu-NP1, Cu-NP2, and Cu-NP3, respectively) were selected for sub-acute toxicity assessment. All procedures performed in this study involving fish handling were in accordance with the research ethical standards approved by the Ethics Committee of the Government College University Faisalabad, Pakistan on Animal Experimentation. The fish in triplicated tanks were exposed to different concentrations (0, 0.5, 1, and 1.5 mg/l) of Cu-NPs for 14 days. About 85% of water change was performed after every 12 h with re-dosing of Cu-NPs to help to retain water quality. Water samples were daily assessed during the experiment to maintain pH, temperature, dissolved oxygen, total ammonia, and water hardness. Five fish per aquarium were randomly sampled at day 0 and 15 for the analysis of oxidative stress enzymes (LPO, GSH, and CAT) in gill tissues and gill histology. Two–three millimeter of each fish gill was fixed in fixative for histology and the remaining part was used for oxidative stress enzymes analysis. Fish mortality and behavior were also recorded.
Impact of polyculture in aquaponics on the hemato-serological and health status of Nile tilapia (Oreochromis niloticus) and carp (Cyprinus carpio)
Published in Egyptian Journal of Basic and Applied Sciences, 2023
Aya H. Khalil, Ahmed E. A. Badrey, Ahmed S. Harabawy, Ahmed Th. A Ibrahim, Werner Kloas, Alaa G. M. Osman
Uncertainty surrounds the physiological functions of urea, uric acid, and creatinine. They are, however, useful indicators of fish gill and kidney health [38], feed consumption [39], and amino acid (arginine) requirements [40]. More than 50% of the nitrogenous waste discharged by the fish kidney is made up of creatine [38]. In the present study, it was shown that the average values of creatinine and urea decreased between monoculture and polyculture in Nile tilapia and common carp, implying good health status during this experiment. These results agree with those of Sánchez-Muros [41]. AST and ALT levels in the blood serum are indicators of continuing chemical processes within animal body [42]. Of the enzyme activities under the current investigation, an unequivocal difference was observed in ALT and AST activities, with mean values higher in Nile tilapia reared in monoculture compared to polyculture. On contrast, the mean values of ALT and AST were lower in common carp reared in polyculture. These results are in accordance with Osman [10], who found significant changes in the levels of ALT and AST in the blood of fish reared in aquaponic systems. Our finding may be explained by the fact that both enzyme levels were within the normal range in aquaponic systems with acceptable water quality, which may have an immune-potentiating effect.
Related Knowledge Centers
- Carbon Dioxide
- Ectoderm
- Endoderm
- Evolution
- Lamprey
- Oxygen
- Pharynx
- Capillary
- Protein Filament
- Countercurrent Exchange