scholarly journals Sodium-Dependent Phosphate Transporter Protein 1 Is Involved in the Active Uptake of Inorganic Phosphate in Nephrocytes of the Kidney and the Translocation of Pi Into the Tubular Epithelial Cells in the Outer Mantle of the Giant Clam, Tridacna squamosa

2021 ◽  
Vol 8 ◽  
Author(s):  
Yuen K. Ip ◽  
Mel V. Boo ◽  
Jeslyn S. T. Poo ◽  
Wai P. Wong ◽  
Shit F. Chew
Keyword(s):  
Epithelial Cells ◽  
Inorganic Phosphate ◽  
Phosphate Transporter ◽  
Giant Clam ◽  
Tubular Epithelial Cells ◽  
Expression Levels ◽  
Transporter Protein ◽  
Giant Clams ◽  
Sodium Dependent ◽  
Tridacna Squamosa

Giant clams display light-enhanced inorganic phosphate (Pi) absorption, but how the absorbed Pi is translocated to the symbiotic dinoflagellates living extracellularly in a tubular system is unknown. They can accumulate Pi in the kidney, but the transport mechanism remains enigmatic. This study aimed to elucidate the possible functions of sodium-dependent phosphate transporter protein 1-homolog (PiT1-like), which co-transport Na+ and H2PO4–, in these two processes. The complete cDNA coding sequence of PiT1-like, which comprised 1,665 bp and encoded 553 amino acids (59.3 kDa), was obtained from the fluted giant clam, Tridacna squamosa. In the kidney, PiT1-like was localized in the plasma membrane of nephrocytes, and could therefore absorb Pi from the hemolymph. As the gene and protein expression levels of PiT1-like were up-regulated in the kidney during illumination, PiT1-like could probably increase the removal of Pi from the hemolymph during light-enhanced Pi uptake. In the ctenidial epithelial cells, PiT1-like had a basolateral localization and its expression was also light-dependent. It might function in Pi sensing and the absorption of Pi from the hemolymph when Pi was limiting. In the outer mantle, PiT1-like was localized in the basolateral membrane of epithelial cells forming the tertiary tubules. It displayed light-enhanced expression levels, indicating that the host could increase the translocation of Pi from the hemolymph into the tubular epithelial cells and subsequently into the luminal fluid to support increased Pi metabolism in the photosynthesizing dinoflagellates. Taken together, the accumulation of Pi in the kidney of giant clams might be unrelated to limiting the availability of Pi to the symbionts to regulate their population.

scholarly journals The Sodium-Dependent Inorganic Phosphate Transporter SLC34A1 (NaPi-IIa) Is Not Localized in the Mouse Brain

2011 ◽  
Vol 59 (9) ◽  
pp. 807-812 ◽  
Author(s):  
Max Larsson ◽  
Cecilie Morland ◽  
Irais Poblete-Naredo ◽  
Jürg Biber ◽  
Niels Christian Danbolt ◽  
...  
Keyword(s):  
Mouse Brain ◽  
Inorganic Phosphate ◽  
Phosphate Transporter ◽  
Sodium Dependent

Inorganic phosphate homeostasis in sodium-dependent phosphate cotransporter Npt2b+/− mice

2011 ◽  
Vol 301 (5) ◽  
pp. F1105-F1113 ◽  
Author(s):  
Akiko Ohi ◽  
Etsuyo Hanabusa ◽  
Otoya Ueda ◽  
Hiroko Segawa ◽  
Naoshi Horiba ◽  
...  
Keyword(s):  
Inorganic Phosphate ◽  
Fibroblast Growth Factor 23 ◽  
High Plasma ◽  
Phosphate Binders ◽  
Ectopic Calcification ◽  
Activity Levels ◽  
Mrna Levels ◽  
Distal Intestine ◽  
Transporter Protein ◽  
Sodium Dependent

An inorganic phosphate (Pi)-restricted diet is important for patients with chronic kidney disease and patients on hemodialysis. Phosphate binders are essential for preventing hyperphosphatemia and ectopic calcification. The sodium-dependent Pi (Na/Pi) transport system is involved in intestinal Pi absorption and is regulated by several factors. The type II sodium-dependent Pi transporter Npt2b is expressed in the brush-border membrane in intestinal epithelial cells and transports Pi. In the present study, we analyzed the phenotype of Npt2b−/− and hetero+/− mice. Npt2b−/− mice died in utero soon after implantation, indicating that Npt2b is essential for early embryonic development. At 4 wk of age, Npt2b+/− mice showed hypophosphatemia and low urinary Pi excretion. Plasma fibroblast growth factor 23 levels were significantly decreased and 1,25(OH)2D3 levels were significantly increased in Npt2b+/− mice compared with Npt2b+/+ mice. Npt2b mRNA levels were reduced to 50% that in Npt2b+/+ mice. In contrast, renal Npt2a and Npt2c transporter protein levels were significantly increased in Npt2b+/− mice. At 20 wk of age, Npt2b+/− mice showed hypophosphaturia and reduced Na/Pi cotransport activity in the distal intestine. Npt2b+/+ mice with adenine-induced renal failure had hyperphosphatemia and high plasma creatinine levels. Npt2b+/− mice treated with adenine had significantly reduced plasma Pi levels compared with Npt2b+/+ mice. Intestinal Npt2b protein and Na+/Pi transport activity levels were significantly lower in Npt2b+/− mice than in the Npt2b+/+ mice. The findings of the present studies suggest that Npt2b is an important target for the prevention of hyperphosphatemia.

scholarly journals Effects of Symbiodiniaceae Phylotypes in Clades A–E on Progeny Performance of Two Giant Clams (Tridacna squamosa and T. crocea) During Early History Life Stages in the South China Sea

2021 ◽  
Vol 8 ◽  
Author(s):  
Chao Long ◽  
Yuehuan Zhang ◽  
Yunqing Li ◽  
Jun Li ◽  
Zihua Zhou ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
The South China Sea ◽  
Giant Clam ◽  
Larval Metamorphosis ◽  
The South ◽  
China Sea ◽  
Giant Clams ◽  
Tridacna Squamosa ◽  
Progeny Performance

Unlike most bivalves, giant clams (tridacnids) harbor symbiotic microalgae (zooxanthellae) in their other fleshy bodies. The effects of mixed populations of zooxanthellae on larval metamorphosis has been reported in several papers, but there have been very few studies on the effects of single zooxanthella species on the establishment of symbiosis in giant clams. In this study, we obtained five pure zooxanthella species (clades A3, B1, C1, D1, E1) from antler coral by molecular identification, and analyzed their effects on the larval metamorphosis and progeny performance of two giant clams, Tridacna squamosa and T. crocea, in the South China Sea. Clam larvae with all five zooxanthella species underwent larval settlement and metamorphosis, and formed the zooxanthellal tubular system. There was some variation in metamorphic rate and time to metamorphosis between clams with different zooxanthella species, but no significant differences in size at metamorphosis. After metamorphosis, larvae with all zooxanthella types continued to develop normally. Mantle color was consistent within clam species and zooxanthella species had no effect on mantle color. However, clam progeny with clade E1 zooxanthellae were smaller than progeny with the other four zooxanthella clades (A3, B1, C1, and D1). Survival rate was over 90% for all progeny and there were no significant differences in survival between progeny with Symbiodinium clades A–E during the entire culture process. Two-way ANOVA analysis revealed that giant clam species was the main factor influencing progeny growth, with some variation in growth attributable to zooxanthella type. Our results provide new information on both the symbiotic relationship between giant clams and zooxanthellae and the mantle coloration of giant clams, and will be useful in giant clam seed production and aquaculture.

Symbiodiniaceae Dinoflagellates Express Urease in Three Subcellular Compartments and Upregulate its Expression Levels in situ in Three Organs of a Giant Clam ( Tridacna squamosa ) During Illumination

2020 ◽  
Vol 56 (6) ◽  
pp. 1696-1711 ◽  
Author(s):  
Yuen Kwong Ip ◽  
Germaine Ching Yun Teng ◽  
Mel Veen Boo ◽  
Jeslyn Shi Ting Poo ◽  
Kum Chew Hiong ◽  
...  
Keyword(s):  
Giant Clam ◽  
Expression Levels ◽  
Subcellular Compartments ◽  
Tridacna Squamosa

scholarly journals Nudel involvement in the high-glucose-induced epithelial-mesenchymal transition of tubular epithelial cells

2019 ◽  
Vol 316 (1) ◽  
pp. F186-F194 ◽  
Author(s):  
Wei Zhang ◽  
Lingling Xing ◽  
Lu Xu ◽  
Xiaoxue Jin ◽  
Yunxia Du ◽  
...  
Keyword(s):  
Cell Migration ◽  
Epithelial Cells ◽  
High Glucose ◽  
Epithelial Mesenchymal Transition ◽  
Smooth Muscle Actin ◽  
Cell Phenotype ◽  
Tubular Epithelial Cells ◽  
Mesenchymal Transition ◽  
Expression Levels ◽  
E Cadherin

Nudel is a newly discovered factor related to cell migration. The tubular epithelial-mesenchymal transition (EMT) includes four steps: the loss of the adhesive properties of epithelial cells, the acquisition of a mesenchymal cell phenotype, the destruction of the tubular basal membrane, and the migration into the renal interstitium. The purpose of this study was to investigate the role of Nudel in the high-glucose-induced EMT of tubular epithelial cells. Human renal proximal tubular epithelial cells (HKCs) were treated with Nudel shRNA to clarify the role and mechanism of Nudel in tubular EMT induced by high glucose. We found that Nudel was expressed at a high level in high-glucose-stimulated HKCs, and the expression of Nudel was associated with the activation of signal transducer and activator of transcription 3. After transfection with Nudel shRNA, we detected the expression levels of E-cadherin, α-smooth muscle actin (α-SMA), and the Wiskott-Aldrich syndrome family of proteins (including WASP, N-WASP, WAVE1, WAVE2, and WAVE3) via assay. Cell migration was analyzed by the scratching method. The results showed that high glucose downregulated E-cadherin expression, upregulated α-SMA expression, and promoted the migration of HKCs. The expression levels of N-WASP, WAVE1, and WAVE2 were also elevated in HKCs treated with high glucose. All changes induced by high glucose were ameliorated by Nudel depletion. We conclude that Nudel participates in the transition and the migration of tubular epithelial cells via the regulation of WASP family proteins.

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