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Mussel is an economically and ecologically important species widely distributed throughout the world. The mussel adheres to the attachment substrate by secreting byssus external to the body. Various environmental and biological factors influence the process of byssus secretion, and the present study investigated the effect of starvation on byssal secretion in the hard-shelled mussel Mytilus coruscus. Histological changes in mussel foot secretory glands and gene expression of mussel foot proteins were also determined. The experimental setup consisted of starvation treatments for 7, 14 and 21 days, and the control groups. The results showed that the number of produced byssus was higher in the starvation group compared to the control (CTR) group, and the starvation group had a significantly higher of byssal shedding number from 6 days of starvation treatment onwards (p < 0.05). The byssal thread diameter was significantly reduced in all starvation treatment groups (p < 0.05). However, starvation treatment had no effect on the length of the byssal thread (p > 0.05). After 21 days of starvation treatment, the byssal thread volume was significantly lower than that of the CTR group (p < 0.05). A significant decrease in the breaking force of the byssal thread was observed after 14 and 21 days of starvation treatment (p < 0.05), along with an upward shift in the breakpoints. Starvation treatment significantly reduced the percentage of foot secretory glands area to total tissue (p < 0.05). The expression of the mussel foot protein genes (Mcfp-1P and Mcfp-1T) was significantly up-regulated at 7 days of starvation treatment (p < 0.05). These findings reveal that starvation weakens byssal thread performance by influencing mussel foot secretory glands, which increases the dislodgment risks of suspended-cultured mussels.

The metamorphosis process is a critical life-changing event for marine invertebrate planktonic larvae to transform into benthic adults, which is crucial for the shellfish bed’s ecosystem stability and seed production in aquaculture. The mechanism of neuroendocrine regulation in the larval metamorphosis of bivalves remains ambiguous. In the present study, the expression of two deiodinase genes, McDx and McDy, was analyzed by whole-mount in situ hybridization at four larval stages in the hard-shelled mussel Mytilus coruscus. The McDx and McDy localized in visceral tissues, nervous system, mantle, and velum, indicating that two deiodinase genes are essential for larval development in M. coruscus. Knockdown of the McDx and McDy in the pediveliger larvae of M. coruscus using electroporation of siRNA significantly (p < 0.001) reduced McDx and McDy expression. McDx and McDy knockdown reduced larval metamorphosis in 45% and 49% of the pediveliger larvae induced by epinephrine (EPI). It is hypothesised that the knockdown effects of McDx and McDy repress metamorphic induction rather than larval viability, which does not elicit a lethal effect. The present study corroborates a synergistic action of the adrenergic and thyroid hormones signalling pathway in M. coruscus, and suggests the role of McDx and McDy in larval development and metamorphic transition.

As an important exploration target in the Sichuan Basin, the Lower Triassic Feixianguan Formation has been previously interpreted to be deposited in the trough-platform margin system according to the genetic model of classic lithofacies paleogeography. However, this model does not apply to the northwestern Sichuan Basin. Accordingly, this study proposed a new genetic model that highlighted the carbonate ramp based on the outcrop sections, drilling and logging data, and seismic sections. A large-scale regional regression was found to occur in Sichuan Basin at the end of the Late Permian, leading to the evolution of the original Kaijiang-Liangping Trough into a very shallow tidal flat/lagoon environment at the beginning of the Early Triassic. The sedimentary pattern during the Early Triassic was different from that during the Late Permian. A total of six long-term cycles (LSC1-LSC6) were identified within the Feixianguan Formation. The deposition of LSC1-LSC3 witnessed the filling of the trough to a large extent, and the depositional periods of LSC4 and LSC5 were the main shoal-forming periods. The Feixianguan Formation in the study area was speculated to be deposited in the continuous continental carbonate ramp. With the intensified uplifting of the Longmenshan island chain and the Kangdian ancient land on the northwestern margin of the Upper Yangtze Platform, a large number of terrigenous materials were input into the study area from west to east, leading to the continuous eastward migration of the carbonate facies belt during the deposition of the Fei 1 and Fei 2 Members. Meanwhile, large-area inner-ramp shoal bodies were formed during the deposition of LSC5. It became possible to find a giant gas reservoir belt in the Feixianguan Formation of the northwestern Sichuan Basin and the results of this study provide a new complement to the existing classic trough-platform margin shoal-forming model.

PURPOSE: The tetraspanin CD151 acts as a promoter of metastasis and invasion in several tumors. However, the role of CD151 in human gastric cancer (HGC) remains unclear. METHODS: Twenty HGC specimens and matched nontumor samples, human gastric epithelial cells (HGEC), and four gastric cancer cell lines were used to analyze CD151 expression. Short hairpin RNA-mediated downregulation of CD151 expression in HGC cells was performed to examine the role of CD151 in the proliferation and metastasis/invasion of HGC cells in vivo and in vitro. The relationship of CD151 with integrin α3 in HGC cells was investigated by silencing integrin α3 followed by co-immunoprecipitation and immunofluorescence staining. Finally, the prognostic value of CD151 and integrin α3 was evaluated by immunohistochemistry in tissue microarrays of 76 HGC patients. RESULTS: CD151 was expressed at higher levels in HGC tissues and HGC cells than in nontumor tissues and HGEC cells. Down-regulation of CD151 by vshRNA-CD151 impaired metastasis and invasion of HGC-27 cells, but did not affect cell proliferation. CD151 formed a complex with integrin α3 in HGC cells. CD151-cDNA transfection rescued the metastatic potential and invasiveness of HGC-27-vshCD151 cells, but not those of HGC-27-vshintegrin α3 cells in vitro. Clinically, CD151 overexpression was significantly correlated with high TNM stage, depth of invasion and positive lymph node involvement (p

Background/Aims: To investigate the beneficial effect of N-Acetylcysteine (NAC) on pancreatic microvascular perfusion in acute necrotizing pancreatitis (ANP). Methods: Fifty-four rats were divided into a control group, an ANP group and an NAC-treated group. The ANP model was established by a retrograde injection of 3% sodium taurocholate into the pancreatic duct. The NAC-treated group received an intravenous infusion of NAC just 2 hours before and 30 minutes after the induction of ANP. The pancreatic microvascular perfusion was measured with laser Doppler flowmetry and pancreatic samples were collected for histological examination. Results: The microvascular perfusion in the NAC-treated group decreased slightly and exhibited a significant increase compared to the ANP group (p<0.01). A pathological examination revealed that edema and inflammatory infiltration decreased, and the hemorrhaging and necrosis of the pancreas were significantly reduced. Conclusions: NAC could improve pancreatic microvascular perfusion and alleviate the severity of sodium taurocholate-induced ANP, possibly representing a new therapeutic approach to prevent the progression of ANP. [ABSTRACT FROM AUTHOR]