Effects of vitrification and post-thawing interval on the cytoskeleton and subsequent fertilization rate of in vitro derived bovine oocytes

Vitrification may alter the cytoskeleton (microtubule, meiotic spindle, microfilament, etc.) and the subsequent fertilization rate of in vitro derived bovine oocytes. This study was conducted to evaluate the effect of vitrification and post-thawing incubation periods on the cytoskeleton and fertilization rate of in vitro matured (IVM) bovine oocytes. Following 22 h of IVM, 184 fresh matured oocytes (MO) were immediately fertilized in vitro and served as a control. The remaining MO (1009) were then vitrified by the solid surface vitrification method. Immediately after thawing, MO were incubated in maturation medium in 5% CO2 at 39 °C for 0, 30, 60, 90 and 120 min respectively. Following incubation, half of the MO from each vitrified-thawed treatment group (0, 30, 60, 90, and 120 min) was stained with fluorescein isothiocyanate conjugated (FITC) and propidium iodide (PI) to evaluate the microtubule and DNA or spindle under laser-scanning confocal microscopy. The remaining half from the vitrified-thawed MO treatment groups was washed three times in Brackett and Oliphant\'s fertilization medium and in vitro fertilized. Cleavage and blastocyst rates were recorded 48 h post-fertilization. Results demonstrated that vitrification damaged MO zona pellucida (ZP), microtubule (MT), meiotic spindle (MS), and caused chromosomal fragmentation. Both the cleavage (84%) and blastocyst rates (50%) of the control group were significantly higher compared to the vitrified-thawed treatment groups. However, extending the incubation period of vitrified MO to 120 min after thawing (prior to fertilization) improved cleavage (65%) and blastocyst (13%) rates 48 h post-fertilization. Fertilizing vitrified MO immediately (0 min group) after thawing resulted in the lowest cleavage (42%) and blastocyst (1.9%) rates. In conclusion, vitrification reduces the subsequent fertilization rate of MO, however, a prolonged post-thawing incubation period (120 min) improves survival, cleavage and blastocyst formation rates, and enhances the reorganization of MO\'s cytoskeleton (MT and MS). Keywords: Vitrification; cytoskeleton; bovine; oocytes; fertilization; in vitro matured South African Journal of Animal Science Vol. 36 (5) 2006: pp.42-4

Determining the global scale size of chorus waves in the magnetosphere

Chorus waves outside the plasmapause influence the Earth's radiation belt dynamics by interacting with energetic electrons via cyclotron and Landau resonance. Recent numerical diffusion experiments indicate that the diffusion process is sensitive to the spatial and temporal scale of variability in the wave-particle interaction, which is reported to be more efficient than that based on the traditional average model. Using Van Allen Probes A and B data from November 2012 to July 2019, the spatial and temporal scale size of chorus waves are calculated by the correlation between the wave amplitudes detected by two satellites with varying spatial separation or time lag. We found that, the chorus wave is incoherent when the spatial extent is greater than 433 km or the time lag lasts ∼10 s, which are significantly smaller than that of plasmaspheric hiss. In addition, the spatial correlations of chorus tend to be higher near noon or with lower geomagnetic activity. The temporal correlations of chorus are always statistically near zero, which are not influenced by the location and geomagnetic activity. Our results can help refine the model of the interactions between energetic particles and chorus waves in the radiation belt

Initial Growth of Single-Crystalline Nanowires: From 3D Nucleation to 2D Growth

The initial growth stage of the single-crystalline Sb and Co nanowires with preferential orientation was studied, which were synthesized in porous anodic alumina membranes by the pulsed electrodeposition technique. It was revealed that the initial growth of the nanowires is a three-dimensional nucleation process, and then gradually transforms to two-dimensional growth via progressive nucleation mechanism, which resulting in a structure transition from polycrystalline to single crystalline. The competition among the nuclei inside the nanoscaled-confined channel and the growth kinetics is responsible for the structure transition of the initial grown nanowires

Counter-current chromatography for the separation of terpenoids: A comprehensive review with respect to the solvent systems employed

Copyright @ 2014 The Authors.This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.Natural products extracts are commonly highly complex mixtures of active compounds and consequently their purification becomes a particularly challenging task. The development of a purification protocol to extract a single active component from the many hundreds that are often present in the mixture is something that can take months or even years to achieve, thus it is important for the natural product chemist to have, at their disposal, a broad range of diverse purification techniques. Counter-current chromatography (CCC) is one such separation technique utilising two immiscible phases, one as the stationary phase (retained in a spinning coil by centrifugal forces) and the second as the mobile phase. The method benefits from a number of advantages when compared with the more traditional liquid-solid separation methods, such as no irreversible adsorption, total recovery of the injected sample, minimal tailing of peaks, low risk of sample denaturation, the ability to accept particulates, and a low solvent consumption. The selection of an appropriate two-phase solvent system is critical to the running of CCC since this is both the mobile and the stationary phase of the system. However, this is also by far the most time consuming aspect of the technique and the one that most inhibits its general take-up. In recent years, numerous natural product purifications have been published using CCC from almost every country across the globe. Many of these papers are devoted to terpenoids-one of the most diverse groups. Naturally occurring terpenoids provide opportunities to discover new drugs but many of them are available at very low levels in nature and a huge number of them still remain unexplored. The collective knowledge on performing successful CCC separations of terpenoids has been gathered and reviewed by the authors, in order to create a comprehensive document that will be of great assistance in performing future purifications. © 2014 The Author(s)

In-situ SERS study on the electro-oxidation with HCOOH on a roughened platinum electrode

The dissociative adsorption and oxidation behavior of HCOOH on Pt was investigated by cyclic voltammogram (CV) and in-situ surface enhanced Raman spectroscopy (SERS) techniques. The in-stiu SERS of HCOOH adsorption, dissociation and oxidation on rough Pt is reported. It is found that HCOOH can spontaneously dissociate. The surface Raman spectra of CO, the strongly adsorbed intermediate and COOH, the weakly adsorbed intermediate of the dissociative adsorption of HCOOH were successfully obtained for the first time. At the same time, the Raman spectra of the finally oxidized product CO2 of HCOOH was also firstly detected. The dual path reaction mechanism for the oxidation of HCOOH was confirmed at molecular level

GLUT1 gene is a potential hypoxic marker in colorectal cancer patients

<p>Abstract</p> <p>Background</p> <p>Tumor hypoxia is an important factor related to tumor resistance to radiotherapy and chemotherapy. This study investigated molecules synthesized in colorectal cancer cells during hypoxia to explore the possibility of developing molecular probes capable of detecting cell death and/or the efficiency of radiotherapy and chemotherapy.</p> <p>Methods</p> <p>At first, we incubated two human colorectal adenocarcinoma cell lines SW480 (UICC stage II) and SW620 (UICC stage III) cells in hypoxic (≤2% O₂, 93% N₂, and 5% CO₂) and normoxic conditions (20% O₂, 75% N₂, and 5% CO₂) for 24 h and 48 h. The relative expression ratio of GLUT1 mRNA in hypoxic conditions was analyzed by RT-PCR. Ten cancerous tissues collected from human colorectal cancer patients were examined. HIF-1α and HIF-2α levels were measured to indicate the degree of hypoxia, and gene expression under hypoxic conditions was determined. As a comparison, HIF-1α, HIF-2α, and GLUT1 levels were measured in the peripheral blood of 100 CRC patients.</p> <p>Results</p> <p>Hypoxia-induced lactate was found to be elevated 3.24- to 3.36-fold in SW480 cells, and 3.06- to 3.17-fold in SW620 cells. The increased relative expression ratio of GLUT1 mRNA, under hypoxic conditions was higher in SW620 cells (1.39- to 1.72-fold elevation) than in SW480 cells (1.24- to 1.66-fold elevation). HIF-1α and HIF-2α levels were elevated and GLUT1 genes were significantly overexpressed in CRC tissue specimens. The elevated ratio of GLUT1 was higher in stage III and IV CRC tissue specimens than in the stage I and II (2.97–4.73 versus 1.44–2.11). GLUT1 mRNA was also increased in the peripheral blood of stage II and III CRC patients as compared to stage I patients, suggesting that GLUT1 may serve as a hypoxic indicator in CRC patients.</p> <p>Conclusion</p> <p>In conclusion, this study demonstrated that GLUT1 has the potential to be employed as a molecular marker to indicate the degree of hypoxia experienced by tumors circulating in the blood of cancer patients.</p

Characterization of Bioactive Recombinant Human Lysozyme Expressed in Milk of Cloned Transgenic Cattle

BACKGROUND: There is great potential for using transgenic technology to improve the quality of cow milk and to produce biopharmaceuticals within the mammary gland. Lysozyme, a bactericidal protein that protects human infants from microbial infections, is highly expressed in human milk but is found in only trace amounts in cow milk. METHODOLOGY/PRINCIPAL FINDINGS: We have produced 17 healthy cloned cattle expressing recombinant human lysozyme using somatic cell nuclear transfer. In this study, we just focus on four transgenic cattle which were natural lactation. The expression level of the recombinant lysozyme was up to 25.96 mg/L, as measured by radioimmunoassay. Purified recombinant human lysozyme showed the same physicochemical properties, such as molecular mass and bacterial lysis, as its natural counterpart. Moreover, both recombinant and natural lysozyme had similar conditions for reactivity as well as for pH and temperature stability during in vitro simulations. The gross composition of transgenic and non-transgenic milk, including levels of lactose, total protein, total fat, and total solids were not found significant differences. CONCLUSIONS/SIGNIFICANCE: Thus, our study not only describes transgenic cattle whose milk offers the similar nutritional benefits as human milk but also reports techniques that could be further refined for production of active human lysozyme on a large scale