AANAT transgenic sheep generated via OPS vitrified-microinjected pronuclear embryos and reproduction efficiency of the transgenic offspring

Background The open pulled straw (OPS) vitrification method has been successfully applied in mouse, pig, and goat embryos as well as in buffalo oocytes, but it has not yet been applied to the microinjected embryos. This study examined the effects of OPS vitrification on embryo development and the reproductive capacity of the transgenic offspring in order to establish a method for preservation of microinjected embryos. Methods Ovine pronuclear embryos were microinjected with the exogenous aralkylamine N-acetyltransferase gene (AANAT), frozen by the OPS method, and subsequently thawed for embryo transplantation. Pregnancy rate, lambing rate, survival rate, average birth weight and transgenic positive rate as well as reproduction efficiency and hormone level of the transgenic offspring were investigated to analyze the effect of OPS vitrification on microinjectd pronuclear embryos. Results No significant differences were observed in the birth rate, lamb survival rate and transgenic positive rate between the frozen and non-frozen AANAT-microinjected pronuclear embryos. The average birth weight of the frozen embryos offspring was greater than that of the non-frozen embryos. Importantly, the transgenic offspring that overexpressed the AANAT gene showed improved ovulation efficiency and lambing rate by regulating their hormone levels. Conclusions The OPS vitrification approach may be a valuable method in microinjected- embryo transfer technology, which could reserve embryos and result in fewer unnecessary animal sacrifices. In addition, the AANAT+ transgenic offspring exhibited improved reproductive capacity on account of regulation effect of melatonin on reproductive hormone. These data may provide available references for human-assisted reproduction

Two new O- and C-glycosylxanthones from <i>Gentiana tizuensis </i>Franch^†

950-952Two new xanthone glycoside, 3-O-β--glucopyranosyl- 1,6-dihydroxyxanthone 1 and 3-C-β--glucopyranosyl-1- hydroxy-7-methoxyxanthone 2 have been isolared from the aerial parts of Gentiane tizuensis. Their structures have been established by spectroscopic studies (FABMS, 1H NMR, 13C NMR, DEPT and COSY) and by comparison with closely related compounds

Synthesis and characterization of soluble and transparent co-polyimides with controlled glass transition temperature

271-277<span style="font-size:11.0pt;mso-bidi-font-size: 10.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="" lang="EN-US">Two dianhydrides, namely 4,4'-oxydiphthalic dianhydride and 2,2’-Bis[4-(3,4-dicarboxyphenoxy)phenyl] propane dianhydride, and one diamine (4,4’-Diaminodiphenyl sulphone), <span style="font-size:11.0pt; mso-bidi-font-size:10.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:="" simhei;mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:="" ar-sa"="" lang="EN-US">have been<span style="font-size:11.0pt;mso-bidi-font-size: 10.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="" lang="EN-US"> used for the synthesis of a<span style="font-size:11.0pt; mso-bidi-font-size:10.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:="" simhei;mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:="" ar-sa"="" lang="EN-US"> novel co-<span style="font-size:11.0pt;mso-bidi-font-size: 10.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="" lang="EN-US">polyimide with good solubility, high visible light transparency and high thermal stability. The solubility in several solvents of polyimides with different proportion of dianhydrides has been tested, and the glass transition temperature is determined by differential scanning calorimetry. The polyimide film has been prepared and the optical transmittance is mensurated. The polyimides solubility and light transmittance improved by introducing flexible monomer, and the glass transition temperature of the polyimides is well controlled by the content of 2,2’-Bis[4-(3,4-dicarboxyphenoxy)phenyl] propane dianhydride that has the flexible isopropylidene structure.</span

Effects of melatonin administration on embryo implantation and offspring growth in mice under different schedules of photoperiodic exposure

Abstract Background Embryo implantation is crucial for animal reproduction. Unsuccessful embryo implantation leads to pregnancy failure, especially in human-assisted conception. Environmental factors have a profound impact on embryo implantation. Because people are being exposed to more light at night, the influence of long-term light exposure on embryo implantation should be explored. Methods The effects of long photoperiodic exposure and melatonin on embryo implantation and offspring growth were examined. Long photoperiodic exposure (18:6 h light:dark) was selected to resemble light pollution. Melatonin (10−2, 10−3, 10−4, 10−5 M) was added to the drinking water of mice starting at Day 1 (vaginal plugs) until delivery. Results Melatonin treatment (10−4,10−5 M) significantly increased litter sizes compared to untreated controls (12.9 ± 0.40 and 12.2 ± 1.01 vs. 11.5 ± 0.43; P < 0.05). The most effective concentration of melatonin (10−4 M) was selected for further investigation. No remarkable differences were found between melatonin-treated mice and controls in terms of the pups’ birth weights, weaning survival rates, and weaning weights. Long photoperiodic exposure significantly reduced the number of implantation sites in treated mice compared to controls (light/dark, 12/12 h), and melatonin rescued this negative effect. Mechanistic studies revealed that melatonin enhanced the serum 17β-estradiol (E2) levels in the pregnant mice and upregulated the expression of the receptors MT1 and MT2 and p53 in uterine tissue. All of these factors may contribute to the beneficial effects of melatonin on embryo implantation in mice. Conclusion Melatonin treatment was associated with beneficial effects in pregnant mice, especially those subjected to long photoperiodic exposure. This was achieved by enhanced embryo implantation. At the molecular level, melatonin administration probably increases the E2 level during pregnancy and upregulates p53 expression by activating MT1/2 in the uterus. All of the changes may improve the microenvironment of the uterus and, thus, the outcomes of pregnancy

Surface strengthening mechanism of graphene-oxide membrane and its modified aluminium lamina under penetration loading

The contact surface is crucial in determining the ability of membranes or laminas to absorb energy during penetration. This study conducted experiments to explore the mechanical properties of the pristine graphene oxide (GO) membrane when dry, as well as the anti-penetration performance of four surface-modified GO membranes (dry, oil, water, and grease) under various loading velocities. Dynamic penetration occurs when the kinetic energy exceeds a specific threshold, as opposed to the quasi-static outcomes. Additionally, the examination of failure mode indicated that the GO membrane demonstrates significant elastic rebound when subjected to comparatively lower levels of dynamic loading. Further analysis after penetration revealed a transition from brittleness to ductility under dynamic loading conditions. Uniaxial tensile tests of aluminium sheets revealed a distinct negative velocity sensitivity behaviour. Moreover, surface treatment with the GO membrane can enhance the penetration failure strength and energy absorption capacity of the sheet. This study provides crucial insights into the physical principles governing the energy absorption of membrane structures and how they are influenced by surface conditions

Effects of Melatonin on Early Pregnancy in Mouse: Involving the Regulation of StAR, Cyp11a1, and Ihh Expression

To test whether melatonin plays an important role in the process of early pregnancy, melatonin was given in drinking water to pregnant mice at different gestation stages. These included mice who were given melatonin 14 days prior to their successful mating (confirmed by vaginal plug) (Group A), after successful mating (Group B), and 14 days prior to and until after successful mating (Group C). Melatonin administration significantly enhanced serum as well as ovarian melatonin levels in the mice. It was observed that melatonin did not affect the natural estrous of mice. On day 0.5 of gestation (D0.5), melatonin not only elevated progesterone (P) secretion, but also upregulated expressions of StAR and Cyp11a1, the two marker genes of corpus luteum in ovaries (p &lt; 0.05). Group A had a significantly lower estradiol (E2) secretion and a higher number of implantation sites as well as litter size than controls (p &lt; 0.05) and also had an increased Ihh expression in endometrium of D7.5 gestation. Melatonin treatment after successful mating improved the progesterone (P) secretion at D7.5 of gestation (p &lt; 0.05) and significantly induced leukaemia inhibitory factor (LIF) expression (p &lt; 0.05). Our study indicates that melatonin treatment up-regulated the genes involved in pregnenolone synthesis in ovary and Ihh expression in uterine endometrium. The mechanisms of melatonin to improve embryo implantation related to their actions on promoting the development of corpus luteum before gestation and helping to specify uterine receptivity in early pregnant mice

Melatonin Promotes the In Vitro Development of Microinjected Pronuclear Mouse Embryos via Its Anti-Oxidative and Anti-Apoptotic Effects

CRISPR/Cas9 (Clustered regularly interspaced short palindromic repeats) combined with pronuclear microinjection has become the most effective method for producing transgenic animals. However, the relatively low embryo developmental rate limits its application. In the current study, it was observed that 10−7 M melatonin is considered an optimum concentration and significantly promoted the in vitro development of murine microinjected pronuclear embryos, as indicated by the increased blastocyst rate, hatching blastocyst rate and blastocyst cell number. When these blastocysts were implanted into recipient mice, the pregnancy rate and birth rate were significantly higher than those of the microinjected control, respectively. Mechanistic studies revealed that melatonin treatment reduced reactive oxygen species (ROS) production and cellular apoptosis during in vitro embryo development and improved the quality of the blastocysts. The implantation of quality-improved blastocysts led to elevated pregnancy and birth rates. In conclusion, the results revealed that the anti-oxidative and anti-apoptotic activities of melatonin improved the quality of microinjected pronuclear embryos and subsequently increased both the efficiency of embryo implantation and the birth rate of the pups. Therefore, the melatonin supplementation may provide a novel alternative method for generating large numbers of transgenic mice and this method can probably be used in human-assisted reproduction and genome editing

Melatonin Improves the Quality of <i>In Vitro</i> Produced (IVP) Bovine Embryos: Implications for Blastocyst Development, Cryotolerance, and Modifications of Relevant Gene Expression

<div><p>To evaluate the potential effects of melatonin on the kinetics of embryo development and quality of blastocyst during the process of <i>in vitro</i> bovine embryo culture. Bovine cumulus–oocyte complexes (COCs) were fertilized after <i>in vitro</i> maturation. The presumed zygotes were cultured in <i>in vitro</i> culture medium supplemented with or without 10⁻⁷ M melatonin. The cleavage rate, 8-cell rate and blastocyst rate were examined to identify the kinetics of embryo development. The hatched blastocyst rate, mortality rate after thawing and the relevant transcript abundance were measured to evaluate the quality of blastocyst. The results showed that melatonin significantly promoted the cleavage rate and 8-cell embryo yield of <i>in vitro</i> produced bovine embryo. In addition, significantly more blastocysts were observed by Day 7 of embryo culture at the presence of melatonin. These results indicated that melatonin accelerated the development of <i>in vitro</i> produced bovine embryos. Following vitrification at Day 7 of embryo culture, melatonin (10⁻⁷ M) significantly increased the hatched blastocyst rate from 24 h to 72 h and decreased the mortality rate from 48 h to 72 h after thawing. The presence of melatonin during the embryo culture resulted in a significant increase in the gene expressions of <i>DNMT3A</i>, <i>OCC</i>, <i>CDH1</i> and decrease in that of <i>AQP3</i> after thawing. In conclusion, melatonin not only promoted blastocyst yield and accelerated <i>in vitro</i> bovine embryo development, but also improved the quality of blastocysts which was indexed by an elevated cryotolerance and the up-regulated expressions of developmentally important genes.</p></div

Effects of melatonin on blastocyst re-expansion and survival following vitrification and thawing.

<p>A: hatched blastocyst rate at different times after thawing. B: mortality rate at different times after thawing. Different superscripts indicate significant differences (P<0.05) between treatments at a given time point.</p

Effects of melatonin on the gene expression of developmentally important genes.

<p>Eight developmentally important genes (DNMT3A, SLC2A3, IFNT2, OCC, TJP1, HSPA1A, AQP3, CDH1) were detected in bovine blastosyst after thawing. The letters of a and b represent statistically significant differences (P<0.05).</p