Idebenone relieves the damage of heat stress on the maturation and developmental competence of porcine oocytes.

The reproductive function of animals is often affected by climatic conditions. High-temperature conditions can cause damage to oocyte maturation and embryonic development in a variety of ways. The purpose of this study was to prove that supplementation idebenone (IDB) to the maturation medium can improve the maturation and development of porcine oocytes after heat stress (HS). Porcine cumulus-oocyte complexes (COCs) were cultured in the maturation medium with different concentrations of IDB (0, 0.1, 1 and 10 µM) for 44 hr at either 38.5°C or under the HS conditions. The cumulus oophorus expansion, nuclear maturation and blastocyst rate after parthenogenetic activation (PA) were measured. We found that HS (in vitro maturation 20-24 hr, 42°C) exposure significantly reduced cumulus expansion index and maturation rate of oocytes and the blastocyst rate of PA embryos, while IDB supplementation significantly improved oocyte maturation and development to the blastocysts stage after PA. Moreover, the addition of IDB decreased the intracellular level of ROS and increased GSH content, hence enhancing the antioxidant capacity of oocytes under HS. Meanwhile, IDB treatment also obviously improved the mitochondrial membrane potential and ATP synthesis of oocytes under HS conditions. Furthermore, IDB treatment increased the expression of GDF9 and BMP15 in IVM oocytes which attribute to improve the quality and outcome of IVM oocytes and the development competence of PA embryos in pigs. In summary, we demonstrated that IDB supplementation into the maturation medium exerted protective effects and improved the ability of maturation and developmental competence of porcine oocytes exposed to HS.

Electronic excitation induced hydrogen-bond adjustment and lattice control in organic-inorganic hybrid cubic perovskites: a fixed occupation molecular dynamics study.

The organic-inorganic hybrid perovskite has become a new type of semiconductor for low cost and highly efficient solar cells. However, the mechanism of interactions between the organic cation and the inorganic framework is still not completely clear under optical electronic excitation. In this work, we employ first-principles molecular dynamics with electronic excitation effects to prove that the hydrogen-bond interaction between the molecular cation and the inorganic lattice can be readily adjusted by several-percentage-valence-electron excitations in cubic CH3NH3PbI3. While the hydrogen-bond interaction causes serious lattice distortions, the electronic excitation can recover the lattice symmetry largely by weakening hydrogen bonding. The study offers atomic dynamics to understand the excitation process in the organic-inorganic hybrid perovskite semiconductor.

EsGLUT4 and CHHBP are involved in the regulation of glucose homeostasis in the crustacean Eriocheir sinensis.

Glucose is an essential energy source for both vertebrates and invertebrates. In mammals, glucose uptake is mediated primarily by glucose transporters (GLUTs), members of the major facilitator superfamily (MFS) of passive transporters. Among the GLUTs, GLUT4 is the main glucose transporter in muscles and adipocytes. In skeletal muscle cells, GLUT4 interacts with the lipid raft protein flotillin to transport glucose upon stimulation by insulin. Although several studies have examined GLUT4 function in mammals, few have been performed in crustaceans, which also use glucose as their main energy source. Crustacean hyperglycemic hormone (CHH) is a multifunctional neurohormone found only in arthropods, and one of its roles is to regulate glucose homeostasis. However, the molecular mechanism that underlies CHH regulation and whether GLUT4 is involved in its regulation in crustaceans remain unclear. In the present study, we identified a full-length GLUT4 cDNA sequence (defined herein as EsGLUT4) from the Chinese mitten crab Eriocheir sinensis and analyzed its tissue distribution and cellular localization. By the ForteBio Octet system, two large hydrophilic regions within EsGLUT4 were found to interact with the CHH binding protein (CHHBP), an E. sinensis flotillin-like protein. Interestingly, live-cell imaging indicated that EsGLUT4 and CHHBP responded simultaneously upon stimulation by CHH, resulting in glucose release. In contrast to insulin-dependent GLUT4, however, EsGLUT4 and CHHBP were present within cytoplasmic vesicles, both translocating to the plasma membrane upon CHH stimulation. In conclusion, our results provide new evidence for the involvement of EsGLUT4 and CHHBP in the regulation of glucose homeostasis in crustacean carbohydrate metabolism.

Identification and characterization of a Masculinizer (Masc) gene involved in sex differentiation in Artemia.

The sex of relatively primitive animals such as invertebrates is mostly determined by environmental factors and chromosome ploidy. Heteromorphic chromosomes may also play an important role, as in the ZW system in lepidopterans. However, the mechanisms of these various sex determination systems are still largely undefined. In the present study, a Masculinizer gene (Ar-Masc) was identified in the crustacean Artemia franciscana Kellogg 1906. Sequence analysis revealed that the 1140-bp full-length open reading frame of Ar-Masc encodes a 380-aa protein containing two CCCH-type zinc finger domains having a high degree of shared identities with the MASC protein characterized in the silkworm Bombyx mori, which has been determined to participate in the production of male-specific splice variants. Furthermore, although Ar-Masc could be detected in almost all stages in both sexual and parthenogenetic Artemia, there were significant variations in expression between these two reproductive modes. Firstly, qRT-PCR and Western blot analysis showed that levels of both Ar-Masc mRNA and protein in sexual nauplii were much higher than in parthenogenetic nauplii throughout the hatching process. Secondly, both sexual and parthenogenetic Artemia had decreased levels of Ar-Masc along with the embryonic developmental stages, while the sexual ones had a relatively higher and more stable expression than those of parthenogenetic ones. Thirdly, immunofluorescence analysis determined that sexual individuals had higher levels of Ar-MASC protein than parthenogenetic individuals during embryonic development. Lastly, RNA interference with dsRNA showed that gene silencing of Ar-Masc in sexual A. franciscana caused the female-male ratio of progeny to be 2.19:1. These data suggest that Ar-Masc participates in the process of sex determination in A. franciscana, and provide insight into the evolution of sex determination in sexual organisms.

Prawn lipocalin: characterization of a color shift induced by gene knockdown and ligand binding assay.

The lipocalin family of proteins functions in the transport of steroids, carotenoids, retinoids, and other small hydrophobic molecules. Recently, a lipocalin (MrLC) was isolated from the prawn Macrobrachium rosenbergii and its expression varied with the molting cycle. In this study, knockdown of the MrLC gene by RNA interference (RNAi) was performed and resulted in a shift in body color from blue to orangish red over the entire carapace. By immune-gold electron microscopy, MrLC was found to co-localize with the lipid droplets in subepidermal adiose tissue that were found to be decreased dramatically in MrLC knockdown prawns, in which a reduction in relative fat content was also quantified. Furthermore, MrLC was found to specifically bind astaxanthin and molt hormone (20-hydroxyecdysone) in both in vitro ligand binding assay and in vivo native ligand detection. These results suggested that MrLC plays roles in the regulation of coloration through its association with astaxanthin and may also be involved in the regulation of molting in crustacean.

A novel terminal ampullae peptide is involved in the proteolytic activity of sperm in the prawn, Macrobrachium rosenbergii.

As the distal part of the crustacean male reproductive tract, terminal ampullae play important roles in sperm development and storage of mature spermatophores. In the present study, the novel gene terminal ampullae peptide (TAP) was cloned from terminal ampullae of the prawn, Macrobrachium rosenbergii. The cDNA sequence consists of 768 nucleotides, with an open-reading frame of 264 nucleotides which encodes a putative 88-amino acid precursor protein with a 17-amino acid residue signal peptide. Western blotting and immunohistochemical analysis revealed that TAP was distributed on terminal ampullae and sperm, and its expression was related to gonad development. To elucidate the functional role of TAP in vivo, we disrupted the TAP gene by RNA interference (RNAi) and evaluated the effect on fertility and several sperm parameters. Although there was no difference in fertility between RNAi-induced prawns and controls, RNAi treatment decreased the sperm gelatinolytic activity and blocked proteolytic activity on the vitelline coat. These data provide evidence that TAP participates in regulating sperm proteolytic activity, and performs a crucial role in sperm maturation and degradation of the vitelline coat during fertilization.

Prawn lipocalin: characteristics and expressional pattern in subepidermal adipose tissue during reproductive molting cycle.

In crustaceans, the fascinating processes of maturation, reproductive molting and carapace coloration are regulated by hydrophobic molecules. Interestingly, most of the molecules are ligands of lipocalin. To understand the role of lipocalin in the aforementioned processes at molecular level, we isolated a cDNA that belongs to the lipocalin family, from a central nervous system cDNA library of Macrobrachium rosenbergii. We monitored the spatial and temporal distributions of the mRNA by using Northern Blotting analysis. Our results demonstrated that this gene expresses abundantly in the subepidermal adipose tissue, while faintly in the hepatopancreas and central nervous system. However, no signal was detected in other tissues including muscle, gill and ovary. Its expression levels in subepidermal adipose tissue during various stages of maturation as well as through the whole molting cycle showed that prawn lipocalin is involved in sexual maturation, as the maximal level was observed just after molt.