Cumulus Layers Research Articles

Reducing the resolution bias in cloud fraction from satellite derived clear‐conservative cloud masks

Clear‐conservative satellite cloud detection algorithms overestimate cloud fraction (CF), the degree to which depends on instrument resolution and the spatial distribution of cloud area, with boundary layer cumulus carrying the largest overestimation. This is because in the standard method of computing CF, partially cloudy pixels contribute in the amount of the pixel's area rather than the true cloud area. Development of analytical and pattern recognition techniques to reduce overestimation has been limited by the lack of coincident long‐term, large scale, and high‐resolution satellite data sets. Such data sets are now available from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Multiangle Imaging SpectroRadiometer (MISR) instruments onboard the satellite, Terra. These data sets are used to determine the resolution required to reduce the CF overestimation to ≤0.01 absolute CF using the standard, analytical, and pattern recognition techniques on perfect, clear‐conservative cloud masks with future instrument design in mind; investigate the challenges of implementing these techniques on MISR's operational clear‐conservative cloud mask; and demonstrate the impact of these techniques on a MISR‐derived CF climatology similar to those used to evaluate climate models. Reducing the median CF bias to ≤0.01 requires resolutions of <45 m and ≤80 m for the standard and analytical techniques, respectively, while the pattern recognition technique has no resolution requirement up to a resolution of 1.2 km. When the pattern recognition technique is applied to 10‐year, December, low cloud climatologies over the tropical Western Atlantic (10°N–20°N and 50°W–60°W) derived from MISR, the average CF reduces from 0.50 to 0.20. This is a large reduction in cloud fraction, particularly when considering the climate sensitivity to low clouds and the use of satellite derived CF climatologies for evaluation of climate model CF and radiative budgets.

Trajectory generation for autonomous soaring UAS

As unmanned aerial vehicles are expected to do more and more advanced tasks, improved range and persistence is required. This paper presents a method of using shallow layer cumulus convection to extend the range and duration of small unmanned aerial vehicles. A simulation model of an X-models XCalubur electric motor-glider is used in combination with a refined 4D parametric thermal model to simulate soaring flight. The parametric thermal model builds on previous successful models with refinements to more accurately describe the weather in northern Europe. The implementation of the variation of the MacCready setting is discussed. Methods for generating efficient trajectories are evaluated and recommendations are made regarding implementation.

Using the Sensitivity of Large-Eddy Simulations to Evaluate Atmospheric Boundary Layer Models

Abstract A simple framework to study the sensitivity of atmospheric boundary layer (ABL) models to the large-scale conditions and forcings is introduced. This framework minimizes the number of parameters necessary to describe the large-scale conditions, subsidence, and radiation. Using this framework, the sensitivity of the stationary ABL to the large-scale boundary conditions [underlying sea surface temperature (SST) and overlying humidity and temperature in the free troposphere] is investigated in large-eddy simulations (LESs). For increasing SST or decreasing free-tropospheric temperature, the LES exhibits a transition from a cloud-free, well-mixed ABL stationary state, through a cloudy, well-mixed stationary state and a stable shallow cumulus stationary state, to an unstable regime with a deepening shallow cumulus layer. For a warm SST, when increasing free-tropospheric humidity, the LES exhibits a transition from a stable shallow cumulus stationary state, through a stable cumulus-under-stratus stationary state, to an unstable regime with a deepening, cumulus-under-stratus layer. For a cool SST, when increasing the free-tropospheric humidity, the LES stationary state exhibits a transition from a cloud-free, well-mixed ABL regime, through a well-mixed cumulus-capped regime, to a stratus-capped regime with a decoupling between the subcloud and cloud layers. This dataset can be used to evaluate other ABL models. As an example, the sensitivity of a bulk model based on the mixing-line model is presented. This bulk model reproduces the LES sensitivity to SST and free-tropospheric temperature for the stable and unstable shallow cumulus regimes, but it is less successful at reproducing the LES sensitivity to free-tropospheric humidity for both shallow cumulus and well-mixed regimes.

Cumulus clouds and convective boundary layers: a tropical perspective on two turbulent shear flows

This paper is a review prepared for the second Marseille Colloquium on the mechanics of turbulence, held in 2011, 50 years after the first. The review covers recent developments in our understanding of the large-scale dynamics of cumulus cloud flows and of the atmospheric boundary layer in the low-wind convective regime that is often encountered in the tropics. It has recently been shown that a variety of cumulus cloud forms and life cycles can be experimentally realized in the laboratory, with the transient diabatic plume taken as the flow model for a cumulus cloud. The plume is subjected to diabatic heating scaled to be dynamically similar to heat release from phase changes in clouds. The experiments are complemented by exact numerical solutions of the Navier–Stokes–Boussinesq equations for plumes with scaled off-source heating. The results show that the Taylor entrainment coefficient first increases with heating, reaches a positive maximum and then drops rapidly to zero or even negative values. This reduction in entrainment is a consequence of structural changes in the flow, smoothing out the convoluted boundaries in the non-diabatic plume, including the tongues engulfing the ambient flow. This is accompanied by a greater degree of mixedness in the core flow because of lower dilution by the ambient fluid. The cloud forms generated depend strongly on the history of the diabatic heating profile in the vertical direction. The striking effects of heating on the flow are attributable to the operation of the baroclinic torque due to the temperature field. The mean baroclinic torque is shown to peak around a quasi-cylindrical sheet situated midway between the axis of the flow and the edges. This torque is shear-enhancing and folds down the engulfment tongues. The increase in mixedness can be traced to an explosive growth in the enstrophy, triggered by a strong fluctuating baroclinic torque that acts as a source, especially at the higher wave numbers, thus enhancing the mixedness. In convective boundary layers field measurements show that, under conditions prevailing in the tropics, the eddy fluxes of momentum and energy do not follow the Monin–Obukhov similarity. Instead, the eddy momentum flux is found to be linear in the wind speed at low winds; and the eddy heat flux is, to a first approximation, governed by free convection laws, with wind acting as a small perturbation on a regime of free convection. A new boundary layer code, based on heat flux scaling rather than wall-stress scaling, shows promising improvements in predictive skills of a general circulation model.

Acrosome reaction in the cumulus oophorus revisited: involvement of a novel sperm-released factor NYD-SP8

Fertilization is a process involving multiple steps that lead to the final fusion of one sperm and the oocyte to form the zygote. One of the steps, acrosome reaction (AR), is an exocytosis process, during which the outer acrosome membrane fuses with the inner sperm membrane, leading to the release of acrosome enzymes that facilitate sperm penetration of the egg investments. Though AR has been investigated for decades, the initial steps of AR in vivo, however, remain largely unknown. A well elucidated model holds the view that AR occurs on the surface of the zona pellucida (ZP), which is triggered by binding of sperm with one of the ZP glycosylated protein, ZP3. However, this model fails to explain the large number of 'falsely' acrosome-reacted sperms found within the cumulus layer in many species examined. With the emerging evidence of cross-talk between sperm and cumulus cells, the potential significance of AR in the cumulus oophorus, the outer layer of the egg, has been gradually revealed. Here we review the acrosome status within the cumulus layer, the cross-talk between sperm and cumulus cells with the involvement of a novel sperm-released factor, NYD-SP8, and re-evaluate the importance and physiological significance of the AR in the cumulus in fertilization.

101 EXTERNAL PARAMETRIC INDICATORS OF IN VITRO DEVELOPMENTALLY COMPETENT WATER BUFFALO OOCYTES

External parametric indicators for in vitro developmentally competent water buffalo oocytes were determined. Oocytes were retrieved from ovarian follicles and classified based on the 1) density of surrounding cumulus cells (Rank A, n = 94: with >5 layers, Rank B, n = 73: with 3 to 5 layers, Rank C, n = 73: with <3 layers, Rank D, n = 63: with irregular or denuded from cumulus cells, and Rank E, n = 42: with expanded cumulus cells, and 2) granulation of ooplasm (Homogeneous, n = 164: evenly granulated, Heterogeneous, n = 180: not evenly granulated where some part is either light or dark), 3) size of the ooplasm, n = 647 (<100, n = 87; 100–119, n = 312; 120–139, n = 164; ≥140 μm, n = 84), and 4) size of the donor antral follicle, n = 688 (<2, n = 244; 2 to 3.9, n = 221; 4 to 5.9, n = 116; 6 to 7.9, n = 61; ≥8 mm, n = 46). Oocytes classified based on these parameters were matured for 22 to 24 h and the nuclear maturation was examined with cleavage rate and blastocyst development rate assessed after in vitro fertilization. To validate the hypothesis that oocytes with compact cumulus (n = 248) are at growing phase while those with loose cumulus (n = 270) are at developmental phase, they were matured and fertilized in vitro at shorter (20 to 22 h) or longer (24 to 26 h) period and embryo development was assessed. Each study was replicated 5 to 10 times. Data were statistically analysed by chi-square test, Fisher’s exact test, and correlation analysis. Results showed that oocytes surrounded by multi-layers (>5 layers) of cumulus cells had highest developmental competence. Oocytes with a diameter of <100 μm lacked developmental competence, evidenced by the failure to develop to metaphase II (MII) after in vitro maturation (IVM), whereas oocytes with diameter of ≥100 μm developed to MII and cleaved after IVF. Optimum cleavage (96.8%) and blastocyst development (27.0%) was observed in oocytes with ≥120 μm. The size of the donor follicle was linearly correlated with oocyte developmental competence with follicles ≥6 mm containing highly developmentally competent oocyte. Based on the findings, oocytes surrounded by >3 layers of compact or loose cumulus with evenly granulated and with ∼110 μm diameter ooplasm and derived from ≥4 mm follicles are developmentally competent. Oocytes with a compact cumulus required 24 to 26 h of IVM while those with loose cumulus required 20 to 22 h of IVM for optimum blastocyst development. These results suggest that the density and compactness of the surrounding cumulus, and the diameter of ooplasm and donor follicles are positive indicators for oocytes with developmental competence.

251 SELECTION OF PREPUBERTAL SHEEP OOCYTES USING BRILLIANT CRESYL BLUE TEST

The aim of this study was to evaluate the utility of the brilliant cresyl blue (BCB) test as an indirect measure of oocyte growth to select competent prepubertal sheep oocytes for in vitro embryo production. The BCB stain allows the determination of glucose–6-phosphate dehydrogenase (G6PD) activity, an enzyme with decreased activity in oocytes that have finished their growth phase. Oocytes were obtained after slicing the surface of lamb ovaries (2–5 months old) obtained from a local abattoir. Oocytes with more than 3 compact cumulus layers and homogeny cytoplasm were selected and stained with different concentrations of BCB diluted in PBS (13-, 26-, 39-, and 52-μM BCB) during 60 min at 38.5°C in a humidified air atmosphere. Oocytes were classified into groups depending on their cytoplasm coloration: oocytes with blue cytoplasm or grown oocytes (BCB+) and oocytes without blue coloration or growing oocytes (BCB–). Oocytes were matured in an enriched TCM-199 medium for 24 h at 38.5°C and 5% CO2 in a humidified atmosphere. Oocyte diameter was also measured. Matured oocytes were partially denuded and transferred to fertilization medium (SOF) supplemented with 10% of oestrous sheep serum. Fresh semen was kept at room temperature (25°C) for 1 h. Highly motile spermatozoa were selected by using Ovipure density gradient (Nidacon EVB S.L.), and oocytes were fertilized with 1 × 106 sp mL–1. After 20 h postinsemination, presumptive zygotes were cultured for 8 days in SOF with 10% of fetal bovine serum at 38.5°C, 5% CO2, and 90% N2. Data was analysed by performing Fisher’s exact test for blastocyst production and ANOVA with Tukey’s post-test for oocyte diameter. Table 1 shows the percentage of BCB-stained oocytes and their embryo development. In this study oocytes exposed during 60 min to 13-μM BCB showed a higher percentage of embryos reaching blastocyst stage than did those in the control group (≤0.01). In other species such as goats (Rodriguez-Gonzalez et al. 2002 Theriogenology 57(5), 1397–1409) and cattle (Alm et al. 2005 Theriogenology 63(8), 2194–2205), the best protocol for the oocyte selection was the use of 26-μM BCB during 90 min. Oocyte diameter showed significant differences between BCB– with BCB+ and control group (110 μm, 134 μm, and 121 μm, respectively, ≤0.001). In conclusion, using 13 μM of BCB during 60 min is a suitable technique for increasing embryo blastocyst rates using lamb oocytes. Table 1.Effect of BCB1 concentration on embryo development of lamb oocytes The grant sponsor was the Spanish Ministry of Science and Innovation, Code: AGL2007-60227-CO2-01.

In Vitro Oocyte Maturation and Preantral Follicle Culture from the Luteal-Phase Baboon Ovary Produce Mature Oocytes

Female cancer patients who seek fertility preservation but cannot undergo ovarian stimulation and embryo preservation may consider 1) retrieval of immature oocytes followed by in vitro maturation (IVM) or 2) ovarian tissue cryopreservation followed by transplantation or in vitro follicle culture. Conventional IVM is carried out during the follicular phase of menstrual cycle. There is limited evidence demonstrating that immature oocyte retrieved during the luteal phase can mature in vitro and be fertilized to produce viable embryos. While in vitro follicle culture is successful in rodents, its application in nonhuman primates has made limited progress. The objective of this study was to investigate the competence of immature luteal-phase oocytes from baboon and to determine the effect of follicle-stimulating hormone (FSH) on baboon preantral follicle culture and oocyte maturation in vitro. Oocytes from small antral follicle cumulus-oocyte complexes (COCs) with multiple cumulus layers (42%) were more likely to resume meiosis and progress to metaphase II (MII) than oocytes with a single layer of cumulus cells or less (23% vs. 3%, respectively). Twenty-four percent of mature oocytes were successfully fertilized by intracytoplasmic sperm injection, and 25% of these developed to morula-stage embryos. Preantral follicles were encapsulated in fibrin-alginate-matrigel matrices and cultured to small antral stage in an FSH-independent manner. FSH negatively impacted follicle health by disrupting the integrity of oocyte and cumulus cells contact. Follicles grown in the absence of FSH produced MII oocytes with normal spindle structure. In conclusion, baboon luteal-phase COCs and oocytes from cultured preantral follicles can be matured in vitro. Oocyte meiotic competence correlated positively with the number of cumulus cell layers. This study clarifies the parameters of the follicle culture system in nonhuman primates and provides foundational data for future clinical development as a fertility preservation option for women with cancer.

PACAP-mediated sperm–cumulus cell interaction promotes fertilization

The developing acrosome in spermatids contains pituitary adenylate cyclase-activating polypeptide (PACAP). However, the role of the acrosomal PACAP remains unclear because it has not been detected in mature spermatids and sperm. We reinvestigated whether the sperm acrosome contains PACAP. An antiserum produced against PACAP reacted to the anterior acrosome in epididymal sperm fixed under mild conditions, suggesting that PACAP acts on oocytes and/or cumulus cells at the site of fertilization. Immunolabeling and RT-PCR demonstrated the presence of PACAP type I receptor, a PACAP-specific receptor, in postovulatory cumulus cells. To investigate the role of PACAP in fertilization, we pretreated cumulus-oocyte complexes with the polypeptide. At a low concentration of sperm, the fertilization rate was significantly enhanced by PACAP in a dose-dependent manner. Sperm penetration through the oocyte investment, cumulus layer, and zona pellucida was also enhanced by PACAP. The enhancement was probably due to an enhancement in sperm motility and the zona-induced acrosome reaction, which were stimulated by a cumulus cell-releasing factor. Indeed, PACAP treatment increased the secretion of progesterone from the cumulus-oocyte complexes. These results strongly suggest that in response to PACAP, cumulus cells release a soluble factor that probably stimulates sperm motility and the acrosome reaction, thereby promoting fertilization.

Observations of detrainment signatures from non-precipitating orographic cumulus clouds

This study uses aircraft in-situ data, airborne mm-wavelength radar data, time lapse photography, and close-proximity radiosonde data to describe the signature of a lifecycle of non-precipitating moist convection left onto the ambient free tropospheric air. The data were collected as part of the 2006 Cumulus Photogrammetric, In-situ and Doppler Observations (CuPIDO-06) campaign, which was centered over the Santa Catalina Mountains, a natural laboratory for the study of the formation and decay of cumulus clouds. This study focuses on one case study, on 8 August 2006, when a series of Cu mediocris formed on the upwind side of the mountain, and decayed on the downwind side. Because these clouds were not precipitating, convective downdrafts were too weak to significantly affect the boundary-layer air downwind of the mountain. The layer containing orographic cumuli clearly became enriched with moist static energy immediately downwind of the mountain. This enrichment was due to the transport of boundary-layer air by moist convection, and not an artifact of stratified flow over a mountain, since it was mostly caused by an increase in water vapor. Some downwind plumes contained over 50% of the water vapor and moist static energy excess found in orographic cumuli over base values in the upstream environment in the orographic cumulus layer. This enrichment reduces potential instability but increases ambient humidity. This may facilitate successive cumulus growth, although this process of convective conditioning is unlikely to be important for meso-γ scale (~ 20 km) orographic convection.

256 ROLE OFTHE BOVINE OOCYTE-SPECIFIC PROTEIN JY-1 IN REGULATION OF MESSENGER RNA ABUNDANCE FOR GENES LINKED TO CUMULUS EXPANSION

We have previously demonstrated a requirement of the oocyte-specific protein JY-1 for oocyte and early embryonic development in cattle. Microin- jection of JY-1 siRNA into cumulus-enclosed germinal vesicle-stage oocytes impedes progression to metaphase II and cumulus expansion during in vitro maturation and limits subsequent embryonic development following in vitro fertilization. Negative effects of siRNA-mediated reduction in JY-1 on oocyte maturation, cumulus expansion, and initial cleavage divisions following in vitro fertilization can be rescued bysupplementation with recom- binant JY-1 protein during oocyte culture. However, the mechanisms involved in JY-1 regulation of above developmental endpoints are unknown. The objective of the current study was to determine whether JY-1-induced regulation of cumulus expansion during meiotic maturation is linked to alterations in mRNA abundance for genes that promote formation and stabilization of the mucified extracellular matrix characteristic of an expanded cumulus layer. Cumulus-enclosed germinal vesicle stage-bovine oocytes were microinjected with JY-1 siRNA, subjected to negative control siRNA microinjection or served as uninjected controls (n = 10 oocytes/treatment; n = 5 replicates), and cultured for 48 h in maturation medium containing 50 μM S-roscovitine to block spontaneous germinal vesicle breakdown. Cumulus-oocyte complexes were then washed and in vitro matured for an additional 24 h in maturation medium minus S-roscovitine. Additional JY-1 siRNA injected and uninjected cumulus-enclosed oocytes were cultured as described earlier but in the presence of 1 ng/mL of recombinant JY-1 protein (n = 10 oocytes/treatment; n = 5 replicates). Dose of recombinant JY-1 protein utilized was previously shown to reverse inhibitory effects of JY-1 siRNA injection on cumulus expansion. After in vitro maturation, cumulus cells were harvested and RNA isolated and subjected to reverse transcription. Real-time PCR analysis was then conducted to determine the effect of treatments on cumulus-cell mRNA abundance for HAS2, HAS3, PTX3, and TNFAIP6. Effects of JY-1 supplementation or depletion (siRNA injection) on cumulus-cell mRNA abundance for HAS2 and HAS3 (enzymes involved in hyaluronan synthesis) were not observed. However, abundance of mRNA for TNFAIP6 and PTX3 (molecules implicated in stabilization of the hyaluronan-rich extracellular matrix) was reduced (relative to uninjected and negative control siRNA groups) in response to JY-1 siRNA injection (P < 0.05) and effects of JY-1 siRNA were rescued by JY-1 protein treatment (P < 0.05). Effects of JY-1 protein supplementation on cumulus-cell TNFAIP6 and PTX3 mRNA in uninjected controls were not observed. Results support a requirement of the oocyte-specific protein JY-1 for regulation of expression of genes functionally linked to stabilization of the hyaluronan-rich extracellular matrix and cumulus expansion. This research was supported by USDA 2008-35203-19094 to G. W. Smith.

Cloud classes and radiative heating profiles at the Manus and Nauru Atmospheric Radiation Measurement (ARM) sites

The tropical western Pacific is a convective regime; however, the frequency and depth of convection is dependent on dynamical forcing which exhibits variability on a range of temporal scales and also on location within the region. Manus Island, Papua New Guinea, lies in the heart of the western Pacific warm pool region and exhibits frequent deep convection much of the time, while Nauru, which lies approximately 20 degrees to the east of Manus, is in a transition zone where the frequency of convection is dependent on the phase of the El Niño−Southern Oscillation. Because of this difference in dynamical regime, the distribution of clouds and the associated radiative heating is quite different at the two sites. Individual cloud types (boundary layer cumulus, thin cirrus, stratiform convective outflow) do occur at both sites, but with different frequencies. In this study we compare cloud profiles and heating profiles for specific cloud types at these two sites using data from the Atmospheric Radiation Measurement (ARM) Climate Research Facility. Results of this comparison indicate that while the frequency of specific cloud types differ between the two sites as one would expect, the characteristics of individual cloud classes are remarkably similar. This information could prove to be very useful for applying tropical ARM data to the broader region.

Factors affecting laboratory production of buffalo embryos: A meta-analysis

In vitro fertilization (IVF) provides an excellent and inexpensive source of embryos for carrying out basic research on developmental physiology, farm animal breeding, and for commercial applications. Meta-analysis of the results from different publications rather than a narrative review may provide a current status of this technology in buffalo (Bubalus bubalis). In order to gain an idea of the factors affecting the IVF in buffalo, a review of the various studies conducted on buffalo IVF and a meta-analysis of their findings was undertaken. More than 100 articles published from 1991 to 2008 were searched, and results were subjected to meta-analysis to determine the treatment variations without any bias. Thirty factors affecting in vitro embryo production in buffalo were considered. Initially, both fixed- and random-effect models were used. We did not observe any heterogeneity between the studies. Thereafter, all the studies were pooled using the fixed-effect model for analysis. Our analysis suggested that good buffalo oocytes with more than three to five cumulus layers recovered from large-sized follicles in cold seasons when cultured in TCM-199 supplemented with serum, follicle-stimulating hormone, and cysteamine resulted in maximum maturation rate and subsequent embryonic development after insemination. The values obtained in the current study may be considered for a simulation model in establishing a cost-effective suitable method for buffalo IVF in further planned research.

A Parameterization of Dry Thermals and Shallow Cumuli for Mesoscale Numerical Weather Prediction

Fornumericalweatherpredictionmodelsandmodelsresolvingdeepconvection, shallowconvectiveascentsaresubgridprocessesthatarenotparameterizedbyclassicallocal turbulent schemes. The mass flux formulation of convective mixing is now largely accepted as an efficient approach for parameterizing the contribution of larger plumes in convec- tive dry and cloudy boundary layers. We propose a new formulation of the EDMF scheme (for Eddy Diffusivity\Mass Flux) based on a single updraft that improves the representa- tion of dry thermals and shallow convective clouds and conserves a correct representation of stratocumulus in mesoscale models. The definition of entrainment and detrainment in the dry part of the updraft is original, and is specified as proportional to the ratio of buoy- ancy to vertical velocity. In the cloudy part of the updraft, the classical buoyancy sorting approach is chosen. The main closure of the scheme is based on the mass flux near the surface, which is proportional to the sub-cloud layer convective velocity scale w∗. The link with the prognostic grid-scale cloud content and cloud cover and the projection on the non- conservative variables is processed by the cloud scheme. The validation of this new for- mulation using large-eddy simulations focused on showing the robustness of the scheme to represent three different boundary layer regimes. For dry convective cases, this parameteri- zation enables a correct representation of the countergradient zone where the mass flux part represents the top entrainment (IHOP case). It can also handle the diurnal cycle of boundary- layer cumulus clouds (EUROCS\ARM) and conserve a realistic evolution of stratocumulus (EUROCS\FIRE).

Chromatin Configurations in the Ferret Germinal Vesicle that Reflect Developmental Competence for In Vitro Maturation

In several mammalian species, the configuration of germinal vesicle (GV) chromatin correlates with the developmental competence of oocytes. Yet, no study has been published on the configuration of GV chromatin in ferret, nor is it known whether a specific configuration predicts meiotic competence in this species, in spite of the potential importance of ferret cloning to the study of human disease and to species conservation efforts. Here, we report on an analysis of the chromatin configuration in ferret GV oocytes and on how they correlate with meiotic development. Three distinct configurations were identified based on the degree of chromatin condensation: (1) fibrillar chromatin (FC), featuring strands of intertwined chromatin occupying most of the visible GV region; (2) intermediate condensed chromatin (ICC), characterized by dense, irregular chromatin masses throughout the GV; and (3) condensed chromatin (CC), which is highly compact and centered around the nucleolus. We also found that chromatin configuration was related to the extent of association with cumulus cells in cumulus-oocyte complexes; CC-configured oocytes were most often surrounded by a compact cumulus layer and also a compact corona but FC-configured oocytes were associated with neither. In addition, increasing chromatin condensation corresponded to an increase in oocyte diameter. Finally, following in vitro culture, significantly more CC-configured oocytes underwent maturation to meiotic metaphase II than did FC- or ICC-configured oocytes. We conclude that, in ferret, chromatin condensation is related to the sequential achievement of meiotic competencies during oocyte growth and differentiation, and thus can be used as a predictor of competence.

The morphology of porcine oocytes is associated with zona pellucida glycoprotein transcript contents

We hypothesized that oocyte morphology may be associated with the accumulation of specific mRNAs encoding proteins responsible for the gamete fertilization ability. Therefore, the aim of the study was to evaluate the transcript levels of porcine zona pellucida (pZP1, pZP2, pZP3 and pZP4) glycoproteins in oocytes classified by a four-grade morphological scale (I-IV) accounting for either a homogeneous cytoplasm and a complete cumulus oophorus (grade I) or a heterogenous cytoplasm and decreased number of cumulus layers in the other grades (II, III and IV). We observed a significant increase of all investigated pZP glycoprotein mRNAs in grade I oocytes as compared to other grades (p<0.05). Our observations suggest that porcine oocyte morphology is associated with pZP transcript contents and may be related to an increased fertilization ability of higher quality oocytes.

Evaluation of the immature human oocytes from unstimulated cycles in polycystic ovary syndrome patients using a novel scoring system

To establish a novel scoring system for human immature oocytes and estimate its prognostic effects on the in vitro maturation (IVM) and developmental potential of human immature oocytes. Prospective study. Hospital-based IVF center. Patients with polycystic ovary syndrome (PCOS) undergoing unstimulated cycles of oocyte retrieval. Immature (germinal vesicle and metaphase I) oocytes were collected from PCOS patients and were evaluated based on morphologic characters. After IVM, the maturation rate, fertilization rate, and cleavage rate were evaluated. The quality of the embryos and the apoptosis of the granulosa cells (GCs) were analyzed as well. Morphologic characters of immature oocytes and maturation rate, fertilization rate, cleavage rate, high-quality embryo formation rate, and the apoptosis of the GCs after IVM. The maturation rate, fertilization rate, cleavage rate, and high-quality embryo formation rate of both MI and GV oocytes reduced with the decrease of the score. There were no differences in maturation, fertilization, and cleavage rates between the MI and GV phase. The apoptosis rate of GCs of grade 1' and 0' oocytes was obvious higher than those of grade 3-4'. Evaluating cumulus layer around the oocyte was a simple but useful method, which played an important role in terms of yielding good prognostic parameters in an embryology laboratory. The scoring system of immature oocytes can correctly reflect the development potential of human oocytes.

Turbulent dispersion in cloud-topped boundary layers

Abstract. Compared to dry boundary layers, dispersion in cloud-topped boundary layers has received less attention. In this LES based numerical study we investigate the dispersion of a passive tracer in the form of Lagrangian particles for four kinds of atmospheric boundary layers: 1) a dry convective boundary layer (for reference), 2) a "smoke" cloud boundary layer in which the turbulence is driven by radiative cooling, 3) a stratocumulus topped boundary layer and 4) a shallow cumulus topped boundary layer. We show that the dispersion characteristics of the smoke cloud boundary layer as well as the stratocumulus situation can be well understood by borrowing concepts from previous studies of dispersion in the dry convective boundary layer. A general result is that the presence of clouds enhances mixing and dispersion – a notion that is not always reflected well in traditional parameterization models, in which clouds usually suppress dispersion by diminishing solar irradiance. The dispersion characteristics of a cumulus cloud layer turn out to be markedly different from the other three cases and the results can not be explained by only considering the well-known top-hat velocity distribution. To understand the surprising characteristics in the shallow cumulus layer, this case has been examined in more detail by 1) determining the velocity distribution conditioned on the distance to the nearest cloud and 2) accounting for the wavelike behaviour associated with the stratified dry environment.

245 CONNEXIN 43 mRNA EXPRESSION AT DIFFERENT TIME POINT IN IN VITRO MATURATION OF BUFFALO OOCYTES

In advanced technologies of ART, the basic requirement is the production of in vitro-matured oocytes, and embryo production efficiency depends on healthy, matured oocytes. Oocyte growth and development depends on the ability of oocytes and their surrounding cumulus granulosa cells (Eppig et al. 1979 J. Exp. Zool. 208, 111–120). Cumulus cells provide carbohydrate precursors, amino acids, and nucleotides to the oocytes (Brower and Schultz 1982 Dev. Biol. 90, 144–153). Oocytes and cumulus cell gap junctions are required for the coordination of cytoplasmic and nuclear maturation (Carabatsos et al. 2002 Dev. Biol. 226, 167–179). In bovine COC, functional gap junctions are required for the progression of oocyte maturation. Gap junctions allow for metabolic coupling between adjacent granulosa cells. Disruption in the integrity of the gap junction inhibits oocyte maturation (Anderson and Albertini 1976 J. Cell Biol. 71, 680–686). The aim of this study was to analyze the trend of Cx43 mRNA transcript in in vitro-matured oocytes at different times of maturation in the Indian water buffalo to estimate the correlation with expression level. Oocytes collected from slaughterhouse ovaries were matured in TCM-199 medium supplemented with 2.5 mm pyruvate, gentamycin sulfate (10 mg mL–1), β-estradiol (1000 ng mL–1), FSH (500 ng mL–1), LH (500 ng mL–1), and 10% FBS at 38.5°C in 5% CO2 in air. Cumulus–oocyte complexes were used after 0, 6, 12, 18, and 24 h of maturation for the cDNA preparation with cells of a cDNA II Kit. Expression of the Cx43 gene was quantified at different time intervals for maturation with real-time PCR. Statistical analysis was performed with one-way ANOVA, followed by Duncan’s multiple pair-wise comparison. Our results showed that Cx43 mRNA abundance was affected by time of maturation. The expression of Cx43 was significantly higher at 6 h than at 18 and 24 h, whereas the 12-h value was intermediate. Our results are in agreement with decreased Cx43 protein contents in the outer cumulus layers of COC at maturation time points (Calder et al. 2003 Reprod. Biol. Endocrinol. 1, 14) and the expression of Cx43 in oocyte development regulation (Granot et al. 2002 Biol. Reprod. 66, 568–573). When Cx43 expression was compared among immature oocytes, denuded oocytes, cumulus cells, and COC at 6 h, there was no significant difference. However, 6-h-matured COC showed significantly higher expression than other groups. Further, our study supported the role of cumulus cells in COC in Cx43-mediated communication (Vozzi et al. 2001 Reproduction 122, 619–628). Differential expression of Cx43 mRNA among varying COC classes indicates that this gene may be a useful marker for oocyte quality to improve in vitro production or somatic cell nuclear transfer rates. Marker genes that predict developmental competence could be used in the optimization of maturation and culture conditions. Understanding the molecular mechanism involved in in vitro oocyte maturation would be an additional advantage in analyzing this complex biological phenomenon to improve embryo production.

Women’s health—what’s new world wide

Women’s health—what’s new world wide