Branchial expression of an aquaporin 3 (AQP-3) homologue is downregulated in the European eelAnguilla anguillafollowing seawater acclimation

2002 ◽  
Vol 205 (17) ◽  
pp. 2643-2651 ◽  
Author(s):  
Christopher P. Cutler ◽  
Gordon Cramb

SUMMARYA cDNA encoding the homologue of mammalian aquaporin 3 (AQP-3) was isolated by reverse transcription—polymerase chain reaction from the gill of the European eel. The derived amino acid sequence shares 67-70% homology with other vertebrate AQP-3 homologues. Northern blot analysis revealed two AQP-3-specific mRNA species of 2.4 kb and 7 kb. AQP-3 mRNA is expressed predominantly in the eye, oesophagus, intestine (as found in mammals) and the gill; no expression could be demonstrated in the stomach and only low and sporadic levels in the kidney. Quantitative studies demonstrated that,following the 3-week acclimation of freshwater (FW)-adapted yellow and silver eels to seawater (SW), transcript abundance in the gill was reduced by 76% and 97%, respectively. The half time of branchial AQP-3 mRNA downregulation in yellow eels was approximately 10 h, with a maximal 94% decrease in expression after 2 days in SW (compared to time-matched FW controls). However, in fish acclimated to SW for more than 4 days, the fall in AQP-3 mRNA abundance recovered slightly, such that after 3 weeks, expression was 16% of that in time-matched FW controls. The potential roles for this aquaporin isoform in water or solute transport in the eel gill are discussed.

1993 ◽  
Vol 264 (6) ◽  
pp. C1570-C1576 ◽  
Author(s):  
J. A. Saye ◽  
N. V. Ragsdale ◽  
R. M. Carey ◽  
M. J. Peach

We have demonstrated that angiotensinogen is synthesized by 3T3-F442A cells and is hydrolyzed to angiotensins I and II (ANG I and II) by this model adipocyte system. This study was designed to determine whether ANG I is generated by renin or some other enzyme and where the formation of ANG I and/or II occurs in 3T3-F442A cells. Renin mRNA was not detected by Northern blot analysis of poly(A)(+)-selected RNA from cultures of fully differentiated adipocytes nor by the more sensitive polymerase chain reaction, implying that renin is not synthesized in this model adipocyte system. Hydrolysis of angiotensinogen to ANG I and II was demonstrated to be associated with the cell but not the media. Inhibitors, including EDTA, aimed at inactivating enzymes belonging to the serine, acid, or aspartyl proteases, and metalloproteases were ineffective in preventing the formation of either ANG I or II. Therefore the model adipocyte 3T3-F442A cell system forms ANG I and II in the absence of renin and angiotensin-converting enzyme. The unidentified enzymes responsible for peptide formation are associated with the cell itself.


1997 ◽  
Vol 45 (1) ◽  
pp. 107-118 ◽  
Author(s):  
André Nadeau ◽  
Gilles Grondin ◽  
Richard Blouin

ZPK is a recently described protein serine/threonine kinase that has been originally identified from a human teratocarcinoma cell line by the polymerase chain reaction and whose function in signal transduction has not yet been elucidated. To investigate the potential role of this protein kinase in developmental processes, we have analyzed the spatial and temporal patterns of expression of the ZPK gene in mouse embryos of different gestational ages. Northern blot analysis revealed a single mRNA species of about 3.5 KB from Day 11 of gestation onwards. In situ hybridization studies demonstrated strong expression of ZPK mRNA in brain and in a variety of embryonic organs that rely on epithelio-mesenchymal interactions for their development, including skin, intestine, pancreas, and kidney. In these tissues, the ZPK mRNA was localized primarily in areas composed of specific types of differentiating cells, and this expression appeared to be upregulated at a time concomitant with the onset of terminal differentiation. Taken together, these observations raise the possibility that the ZPK gene product is involved in the establishment and/or maintenance of a fully cytodifferentiated state in a variety of cell lineages.


2010 ◽  
Vol 135 (4) ◽  
pp. 291-302 ◽  
Author(s):  
Kaori Ando ◽  
Rebecca Grumet

Fruit development proceeds from cell division to expansion, maturation, and ripening. Expansion is critical for size, yield, and quality; however, this period of development has received little attention. We used 454-pyrosequencing to develop a cucumber (Cucumis sativus) fruit transcriptome, identify highly expressed transcripts, and characterize key functions during exponential fruit growth. The resulting 187,406 expressed sequence tags (ESTs) were assembled into 13,878 contigs. Quantitative real-time polymerase chain reaction (qRT-PCR) verification of differentially expressed genes from fruit of different ages, and high correlation in transcript frequency between replicates, indicated that number of reads/contig reflects transcript abundance. Putative homologs were identified in Arabidopsis thaliana for 89% of the contigs represented by at least 10 ESTs; another 4% had homologs in other species. The remainder had homologs only in cucurbit species. The most highly expressed contigs were strongly enriched for growth (aquaporins, vacuolar ATPase, phloem proteins, tubulins, actins, cell wall-associated, and hormone-related), lipid, latex, and defense-related homologs. These results provide a resource for gene expression analysis in cucumber, profile gene expression in rapidly growing fruit, and shed insight into an important, but poorly characterized, developmental stage influencing fruit yield and quality.


2006 ◽  
Vol 42 (5) ◽  
pp. 326-335 ◽  
Author(s):  
Heather L. Chandler ◽  
Carmen M.H. Colitz

The basics of molecular biology involve the replication of deoxyribonucleic acid and its transcription and translation into proteins. Biochemical assays such as the Southern blot analysis, polymerase chain reaction (PCR), Northern blot analysis, reverse-transcriptase PCR, microarray technology, Western blot analysis, immunohistochemistry, enzyme-linked immunosorbent assay, and flow cytometry utilize various aspects of molecular biology. To understand these assays requires some basic understanding of the principles of molecular biology. This paper provides basic information on the methodology and techniques used in these assays.


2018 ◽  
Vol 14 (7) ◽  
pp. 20180269 ◽  
Author(s):  
Kazuki Yokouchi ◽  
Françoise Daverat ◽  
Michael J. Miller ◽  
Nobuto Fukuda ◽  
Ryusuke Sudo ◽  
...  

Many diadromous fishes such as salmon and eels that move between freshwater and the ocean have evolved semelparous reproductive strategies, but both groups display considerable plasticity in characteristics. Factors such as population density and growth, predation risk or reproduction cost have been found to influence timing of maturation. We investigated the relationship between female size at maturity and individual growth trajectories of the long-lived semelparous European eel, Anguilla anguilla . A Bayesian model was applied to 338 individual growth trajectories of maturing migration-stage female silver eels from France, Ireland, the Netherlands and Hungary. The results clearly showed that when growth rates declined, the onset of maturation was triggered, and the eels left their growth habitats and migrated to the spawning area. Therefore, female eels tended to attain larger body size when the growth conditions were good enough to risk spending extra time in their growth habitats. This flexible maturation strategy is likely related to the ability to use diverse habitats with widely ranging growth and survival potentials in the catadromous life-history across its wide species range.


1997 ◽  
Vol 273 (3) ◽  
pp. R928-R933 ◽  
Author(s):  
D. M. Silverstein ◽  
M. Barac-Nieto ◽  
H. Murer ◽  
A. Spitzer

The mRNA that encodes for NaPi-2, the renal Na(+)-Pi cotransporter that is upregulated by Pi depletion in the adult rat, is low in the young animal. Yet, renal Na-Pi cotransport rates are higher in rapidly growing than in fully grown rats. The aim of this study was to unravel the molecular basis of this apparent discrepancy. Poly(A) RNA obtained from the renal cortex of young animals induced higher rates of Na(+)-Pi cotransport in oocytes than equal amounts of poly(A) mRNA obtained from the renal cortex of mature rats. Moreover, poly(A) RNA obtained from renal cortex of rapidly growing animals treated with antisense NaPi-2 oligomers or depleted of NaPi-2 transcripts by subtractive hybridization with cDNA generated from the renal cortex of adult rats retained its ability to induce Na(+)-Pi cotransport in oocytes. In addition, renal poly(A) RNA of the young subjected to subtraction hybridization generated a 379-base pair reverse transcriptase-polymerase chain reaction product common to all known type II Na(+)-Pi cotransporters. These observations permit us to surmise that the high rates of Na(+)-Pi cotransport prevailing during growth are due, at least in part, to the expression of a specific mRNA that is only partially homologous to that of NaPi-2.


2000 ◽  
Vol 279 (1) ◽  
pp. R222-R229 ◽  
Author(s):  
Christopher P. Cutler ◽  
Stephane Brezillon ◽  
Songul Bekir ◽  
Ian L. Sanders ◽  
Neil Hazon ◽  
...  

Recent studies on teleost fish have suggested that their genomes have undergone ancient polyploidization events resulting in the duplication of the genome. A duplicate copy of the Na,K-ATPase β1-isoform (called β233) has been identified in the European eel ( Anguilla anguilla). The β233-isoform shares high levels of nucleotide (74.8%) and amino acid (69.9%) homology with the eel β1-subunit as well as other vertebrate β1-sequences. Compared with the widely expressed β1-isoform, expression of β233-mRNA is mainly restricted to epithelial tissues. Seawater acclimation induced increases in β233-mRNA levels in kidney, gill, and intestine of migratory “silver” but not the nonmigratory “yellow” adult eels, suggesting that the factors responsible for this upregulation are themselves developmentally regulated. Expression of a variably glycosylated 40- to 52-kDa β233-protein in both gill “chloride” and intestinal epithelial cells suggests that the β233-isoform of Na,K-ATPase may play an important functional role in the major osmoregulatory tissues of euryhaline fish such as the eel.


2002 ◽  
Vol 81 (6) ◽  
pp. 380-386 ◽  
Author(s):  
H. Benchabane ◽  
L.-A. Lortie ◽  
N.D. Buckley ◽  
L. Trahan ◽  
M. Frenette

Xylitol is transported by Streptococcus mutans via a constitutive phosphoenolpyruvate:fructose phosphotransferase system (PTS) composed of a IIABC protein. Spontaneous xylitol-resistant strains are depleted in constitutive fructose-PTS activity, exhibit additional phenotypes, and are associated with the caries-preventive properties of xylitol. Polymerase chain-reactions and chromosome walking were used to clone the fxp operon that codes for the constitutive fructose/xylitol-PTS. The operon contained three open reading frames: fxpA, which coded for a putative regulatory protein of the deoxyribose repressor (DeoR) family, fxpB, which coded for a 1-phosphofructokinase, and fxpC, which coded for a IIABC protein of the fructose-PTS family. Northern blot analysis revealed that these genes were co-transcribed into a 4.4-kb mRNA even in the absence of fructose. Inactivation of the fxpC gene conferred resistance to xylitol, confirming its function. The fxp operon is also present in the genomes of other xylitol-sensitive streptococci, which could explain their sensitivity to xylitol.


1997 ◽  
Vol 272 (4) ◽  
pp. C1335-C1344 ◽  
Author(s):  
C. Ding ◽  
E. D. Potter ◽  
W. Qiu ◽  
S. L. Coon ◽  
M. A. Levine ◽  
...  

We used Northern blot analysis, ribonuclease protection assay (RPA), reverse transcriptase-polymerase chain reaction, and in situ hybridization to investigate the hypothesis that the CNG1 isoform of the cyclic nucleotide-gated nonselective cation channel may be widely distributed in tissues of the rat. A cDNA encoding the CNG1 isoform was isolated from rat eye and human retina, and partial sequences were isolated from rat pineal gland and human kidney. Northern blot analysis revealed a 3.1-kilobase (kb) CNG1 transcript in rat eye, pineal gland, pituitary, adrenal gland, and spleen, and a larger transcript of 3.5 kb was found in testis. RPA confirmed the identity of CNG1 mRNA in rat eye, lung, spleen, and brain. Polymerase chain reaction-based detection of the mRNA for CNG1 indicates that the channel is expressed in lower abundance in many other tissues, including thymus, skeletal muscle, heart, and parathyroid gland. The cellular distribution of CNG1 was further studied by in situ hybridization, which demonstrated expression of mRNA in lung, thymus, pineal gland, hippocampus, cerebellum, and cerebral cortex but not in heart or kidney.


Sign in / Sign up

Export Citation Format

Share Document