scholarly journals Expression patterns of two Carbonic anhydrase genes, Na+/K+-ATPase and V-type H+-ATPase in the freshwater crayfish, Cherax quadricarinatus, under different pH

2015 ◽  
Author(s):  
Muhammad Yousuf Ali ◽  
Ana Pavasovic ◽  
Peter B Mather ◽  
Peter J Prentis
Keyword(s):  
Carbonic Anhydrase ◽  
Expression Patterns ◽  
Low Ph ◽  
Freshwater Crayfish ◽  
Acid Base Balance ◽  
Acid Base ◽  
Expression Levels ◽  
High Ph ◽  
Base Balance ◽  
Ph Conditions

Osmoregulation and systemic acid-base balance in decapod crustaceans are largely controlled by a set of transport-related enzymes including carbonic anhydrase (CA), Na + /K + -ATPase (NKA) and V-type- H + -ATPase (HAT). Variable pH levels and changes in osmotic pressure can have a significant impact on the physiology and behaviour of crustaceans. Therefore, it is crucial to understand the mechanisms via which an animal can maintain its internal pH balance and regulate the movement of ions into and out of its cells. Here, we examined expression patterns of the cytoplasmic (CAc) and membrane-associated form (CAg) of CA, NKA α subunit and HAT subunit a in gills of the freshwater crayfish Cherax quadricarinatus. Expression levels of the genes were measured at three pH levels, pH 6.2, 7.2 (control) and 8.2 over a 24 hour period. All genes showed significant differences in expression levels, either among pH treatments or over time. Expression levels of CAc were significantly increased at low pH and decreased at high pH conditions 24 h after transfer to these treatments. Expression increased in low pH after 12 h, and reached their maximum level by 24 h. The membrane-associated form CAg showed changes in expression levels more quickly than CAc. Expression increased for CAg at 6 h post transfer at both low and high pH conditions, but expression remained elevated only at low pH (6.2) at the end of the experiment. Expression of CqNKA significantly increased at 6 h after transfer to pH 6.2 and remained elevated up to 24 h. Expression for HAT and NKA showed similar patterns, where expression significantly increased 6 h post transfer to the low pH conditions and remained significantly elevated throughout the experiment. The only difference in expression between the two genes was that HAT expression decreased significantly 24 h post transfer to high pH conditions. Overall, our data suggest that CAc, CAg, NKA and HAT gene expression is induced at low pH conditions in freshwater crayfish. Further research should examine the physiological underpinnings of these changes in expression to better understand systemic acid/base balance in freshwater crayfish.

scholarly journals Expression patterns of two Carbonic anhydrase genes, Na+/K+-ATPase and V-type H+-ATPase in the freshwater crayfish, Cherax quadricarinatus, under different pH

2015 ◽  
Author(s):  
Muhammad Yousuf Ali ◽  
Ana Pavasovic ◽  
Peter B Mather ◽  
Peter J Prentis
Keyword(s):  
Carbonic Anhydrase ◽  
Expression Patterns ◽  
Low Ph ◽  
Freshwater Crayfish ◽  
Acid Base Balance ◽  
Acid Base ◽  
Expression Levels ◽  
High Ph ◽  
Base Balance ◽  
Ph Conditions

Osmoregulation and systemic acid-base balance in decapod crustaceans are largely controlled by a set of transport-related enzymes including carbonic anhydrase (CA), Na + /K + -ATPase (NKA) and V-type- H + -ATPase (HAT). Variable pH levels and changes in osmotic pressure can have a significant impact on the physiology and behaviour of crustaceans. Therefore, it is crucial to understand the mechanisms via which an animal can maintain its internal pH balance and regulate the movement of ions into and out of its cells. Here, we examined expression patterns of the cytoplasmic (CAc) and membrane-associated form (CAg) of CA, NKA α subunit and HAT subunit a in gills of the freshwater crayfish Cherax quadricarinatus. Expression levels of the genes were measured at three pH levels, pH 6.2, 7.2 (control) and 8.2 over a 24 hour period. All genes showed significant differences in expression levels, either among pH treatments or over time. Expression levels of CAc were significantly increased at low pH and decreased at high pH conditions 24 h after transfer to these treatments. Expression increased in low pH after 12 h, and reached their maximum level by 24 h. The membrane-associated form CAg showed changes in expression levels more quickly than CAc. Expression increased for CAg at 6 h post transfer at both low and high pH conditions, but expression remained elevated only at low pH (6.2) at the end of the experiment. Expression of CqNKA significantly increased at 6 h after transfer to pH 6.2 and remained elevated up to 24 h. Expression for HAT and NKA showed similar patterns, where expression significantly increased 6 h post transfer to the low pH conditions and remained significantly elevated throughout the experiment. The only difference in expression between the two genes was that HAT expression decreased significantly 24 h post transfer to high pH conditions. Overall, our data suggest that CAc, CAg, NKA and HAT gene expression is induced at low pH conditions in freshwater crayfish. Further research should examine the physiological underpinnings of these changes in expression to better understand systemic acid/base balance in freshwater crayfish.

Expression patterns of two carbonic anhydrase genes, Na+/K+-ATPase and V-type H+-ATPase, in the freshwater crayfish, Cherax quadricarinatus, exposed to low pH and high pH

2017 ◽  
Vol 65 (1) ◽  
pp. 50 ◽  
Author(s):  
Muhammad Yousuf Ali ◽  
Ana Pavasovic ◽  
Peter B. Mather ◽  
Peter J. Prentis
Keyword(s):  
Carbonic Anhydrase ◽  
Expression Patterns ◽  
Maximum Level ◽  
Low Ph ◽  
Freshwater Crayfish ◽  
Α Subunit ◽  
Cherax Quadricarinatus ◽  
High Ph ◽  
Internal Ph ◽  
Ph Conditions

Carbonic anhydrase (CA), Na+/K+-ATPase (NKA) and Vacuolar-type H+-ATPase (HAT) play vital roles in osmoregulation and pH balance in decapod crustaceans. As variable pH levels have a significant impact on the physiology of crustaceans, it is crucial to understand the mechanisms by which an animal maintains its internal pH. We examined expression patterns of cytoplasmic (CAc) and membrane-associated form (CAg) of CA, NKA α subunit and HAT subunit a in gills of freshwater crayfish, Cherax quadricarinatus, at three pH levels – 6.2, 7.2 (control) and 8.2 – over 24 h. Expression levels of CAc were significantly increased at low pH and decreased at high pH conditions 24 h after transfer. Expression increased at low pH after 12 h, and reached its maximum level by 24 h. CAg showed a significant increase in expression at 6 h after transfer at low pH. Expression of NKA significantly increased at 6 h after transfer to pH 6.2 and remained elevated for up to 24 h. Expression for HAT and NKA showed similar patterns, where expression significantly increased 6 h after transfer to low pH and remained significantly elevated throughout the experiment. Overall, CAc, CAg, NKA and HAT gene expression is induced at low pH conditions in freshwater crayfish.

Renal regulation of acid-base balance in the bullfrog

1961 ◽  
Vol 201 (6) ◽  
pp. 980-986 ◽  
Author(s):  
Hisato Yoshimura ◽  
Masateru Yata ◽  
Minoru Yuasa ◽  
Robert A. Wolbach
Keyword(s):  
Carbonic Anhydrase ◽  
Ammonia Excretion ◽  
Respiratory Acidosis ◽  
Acid Base Balance ◽  
Acid Base ◽  
Urinary Ph ◽  
Base Balance ◽  
Chloride Excretion ◽  
Acid Load ◽  
Renal Carbonic Anhydrase

Renal mechanisms for the maintenance of acid-base balance were studied in the normal bullfrog, during metabolic and respiratory acidosis, and after carbonic anhydrase inhibition. Following intravenous administration of 0.3–12 mmole HCl/ kg, as 0.1 n HCl, urinary pH (initially pH 6.3–7.7) did not change significantly. However, urinary ammonia excretion increased more than twofold, and within 3–5 days the cumulative increase was equivalent to the acid load given. Despite the increased ammonia excretion, chloride excretion did not increase after acid loading. In both normal and acidotic bullfrogs ammonia excretion was correlated with an increase in urinary pH. Respiratory acidosis in the small frog, Rana limnocharis, produced by exposure to 6.4% CO2 in air, induced neither urinary acidification nor increased ammonia excretion; both urinary sodium and bicarbonate excretion increased. When renal carbonic anhydrase was inhibited by acetazoleamide injection, urine flow, sodium excretion, and bicarbonate excretion increased markedly, urinary pH increased slightly, and urinary ammonia excretion remained unchanged. These renal responses to acidosis are compared with those of the acidotic dog.

Use of a carbonic anhydrase Ca17a knockout to investigate mechanisms of ion uptake in zebrafish (Danio rerio)

2021 ◽  
Vol 320 (1) ◽  
pp. R55-R68
Author(s):  
Alex M. Zimmer ◽  
Milica Mandic ◽  
Hong Meng Yew ◽  
Emma Kunert ◽  
Yihang K. Pan ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Danio Rerio ◽  
Ammonia Excretion ◽  
Ion Uptake ◽  
Whole Body ◽  
Acid Base Balance ◽  
Acid Base ◽  
Uptake Mechanism ◽  
Uptake Rates ◽  
Base Balance

In fishes, branchial cytosolic carbonic anhydrase (CA) plays an important role in ion and acid-base regulation. The Ca17a isoform in zebrafish ( Danio rerio) is expressed abundantly in Na+-absorbing/H+-secreting H+-ATPase-rich (HR) cells. The present study aimed to identify the role of Ca17a in ion and acid-base regulation across life stages using CRISPR/Cas9 gene editing. However, in preliminary experiments, we established that ca17a knockout is lethal with ca17a−/− mutants exhibiting a significant decrease in survival beginning at ∼12 days postfertilization (dpf) and with no individuals surviving past 19 dpf. Based on these findings, we hypothesized that ca17a−/− mutants would display alterations in ion and acid-base balance and that these physiological disturbances might underlie their early demise. Na+ uptake rates were significantly increased by up to 300% in homozygous mutants compared with wild-type individuals at 4 and 9 dpf; however, whole body Na+ content remained constant. While Cl− uptake was significantly reduced in ca17a−/− mutants, Cl− content was unaffected. Reduction of CA activity by Ca17a morpholino knockdown or ethoxzolamide treatments similarly reduced Cl− uptake, implicating Ca17a in the mechanism of Cl− uptake by larval zebrafish. H+ secretion, O2 consumption, CO2 excretion, and ammonia excretion were generally unaltered in ca17a−/− mutants. In conclusion, while the loss of Ca17a caused marked changes in ion uptake rates, providing strong evidence for a Ca17a-dependent Cl− uptake mechanism, the underlying causes of the lethality of this mutation in zebrafish remain unclear.

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