ABSTRACT
Echinocandin B (ECB) is the key precursor compound of the antifungal drug Anidulafungin. The effects of the five precursor amino acids on ECB biosynthesis were firstly investigated. It showed that although L-threonine was a main compound of the hexapeptide scaffold of ECB, exogenous addition of L-threonine had no significant effect on the increase of ECB fermentation titer. Meanwhile, the ECB fermentation titer with methyl oleate showed two times higher than that of the other carbon sources. Transcription level analysis of the key genes for ECB biosynthesis indicated that the gene an655543 related to L-threonine biosynthesis showed higher value during the fermentation process, therefore, the exogenous addition of L-threonine had no obvious affection. Furthermore, it indicated that the transcription level of gene ecdA might be the main restriction factor for the ECB biosynthesis. The study provided the research foundation for the modification of the ECB producing strains in the following work.
Subject(s)
Antifungal Agents , Echinocandins , Fermentation , Echinocandins/genetics , Echinocandins/chemistry , Antifungal Agents/pharmacology , Antifungal Agents/chemistryABSTRACT
INTRODUCTION: Cell-cell fusion of cytotrophoblasts into the syncytiotrophoblast layer is a key process in placental development. Syncytin, an endogenous retroviral envelope protein, is expressed in placental trophoblasts and specifically mediates syncytiotrophoblast layer formation. Syncytin deficiency has been observed in fetal growth-restricted placentas. Abnormal fetal growth, especially fetal growth restriction, is associated with the decreased expression of glucose transporters. Here, we aimed to determine the role of syncytin in fetal growth restriction in placental glucose transport capacity. METHODS: To better explore the function of syncytin in fetal growth-restricted placenta, we generated an inducible knockout mouse model of syncytin-a gene. The expression levels of glucose transporters in BeWo cells were measured before and after HERV-W knockdown. RESULTS: Syncytin-A disruption was associated with significant abnormalities in placental and fetal development in mice. Syncytin-A destruction causes extensive abnormalities in the maternal-fetal exchange structures in the labyrinth, including an extremely reduced number and dramatically irregular distribution of fetal vessels. Moreover, glucose transporter 1, glucose transporters 3, and connexin 26 expression levels decreased after E14.5. Consistently, low glucose transporter 1, glucose transporter 3, and connexin 26 levels were observed in HERV-W-silenced BeWo cells. DISCUSSION: Syncytin-A is crucial for both syncytiotrophoblast layer development and morphogenesis, suggesting that syncytin-A disruption leads to fetal growth restriction associated with abnormalities in the maternal-fetal exchange barrier and decreased glucose transport.
Subject(s)
Fetal Growth Retardation , Placenta , Animals , Connexin 26/metabolism , Female , Fetal Growth Retardation/genetics , Fetal Growth Retardation/metabolism , Gene Products, env/genetics , Gene Products, env/metabolism , Glucose/metabolism , Glucose Transporter Type 1/genetics , Glucose Transporter Type 1/metabolism , Mice , Mice, Knockout , Placenta/metabolism , Pregnancy , Pregnancy Proteins , Trophoblasts/metabolismABSTRACT
AIM: To study the effects of oxyphenamone (Oxy) on activation of Ca(2+)-activated K+ channels in rabbit mesenteric vascular smooth muscle cells. METHODS: To measure the effect of Oxy on the Ca(2+)-activated K+ channel (BK (Ca) channel) activity in rabbit mesenteric vascular smooth muscle cells by using whole cell patch clamp techniques. RESULTS: Oxy reversibly increase BK (Ca) channel activity in rabbit mesenteric artery smooth muscle cells. Application of Oxy (0.1 mumol.L-1) to the perfusion solution caused significant increase in outward currents and its effect was completely abolished by washout; The outward currents K+ was inhibited by TEA (7.5 mmol.L-1); Oxy activated the BK (Ca) channel in a dose-dependent manner (0.01-10 mumol.L-1). CONCLUSION: Oxy directly increase the activity of BK (Ca) channel activity in rabbit mesenteric vascular smooth muscle cells in dose-dependent manner.
Subject(s)
Cardiotonic Agents/pharmacology , Muscle, Smooth, Vascular/cytology , Myocytes, Smooth Muscle/physiology , Potassium Channels, Calcium-Activated/drug effects , Animals , Mesenteric Arteries/cytology , Organic Chemicals , Patch-Clamp Techniques , RabbitsABSTRACT
AIM: To study the vasorelaxation action of oxyphenamone (Oxy) and its mechanism. METHODS: The contractile response of isolated rabbit renal, femoral and mesentery artery preparations was determined. RESULTS: Oxy was shown to inhibit the contractile force of renal, femoral and mesentery arteries induced by phenylephrine in a concentration dependent manner. The vasorelaxation produced by Oxy was not attenuated by removal of the endothelium. Oxy (10(-6)-10(-4) mol.L-1) relaxed the contractions induced by KCl 30 mmol.L-1 as well as KCl 80 mmol.L-1, but the contraction curve of KCl 80 mmol.L-1 was shifted significantly to the right. Oxy in lower concentration (10(-6) and 5 x 10(-6) mol.L-1) increased the contractions induced by Ang II, and in middle concentration (10(-5) mol.L-1) it did not affect the contractions induced by Ang II. Whereas in higher concentration (5 x 10(-5) mol.L-1) it obviously inhibited the contractions induced by Ang II. CONCLUSION: Oxy showed significant vasorelaxation to various vascular preparations, and its vasorelaxation action is endothelium independent. The mechanism of its vasorelaxations seems to be related with Ca2+ activated K+ channel (Kca channel) and Ca2+ channel in vascular smooth muscle cells but its true mechanism needs further study.
