Mammalian Egg Activation: The Roles of TRPV3 Channels and PLCZ1

Calcium channels at the plasma membrane have been suggested to mediate Ca2+ influx during egg activation. The transient receptor potential (TRP) Ca2+ channel, TRPV3, is differentially expressed in oocytes during maturation, being fully active at MII stage. Specific stimulation of TRPV3 channels in mouse eggs promotes Ca2+ influx sufficient to induce egg activation and parthenogenesis. In chapter 2, we explore the function and distribution dynamics of the TRPV3 channel protein during oocyte maturation. Using dsRNA, TrpV3 overexpression, and inhibitors of protein synthesis, we modified the native expression of the channel and showed that the TRPV3 protein is synthesized and translocated to the plasma membrane during maturation. We demonstrated that 2-APB at the concentration used to promote Ca2+ influx in eggs, specifically and reversibly targets TRPV3 channels, and does not block the IP3 receptor. Finally, we showed that TRPV3 channels functionally interact with the actin cytoskeleton indicating an actin-based regulation of its expression on the plasma membrane. Our results indicated that TRPV3 is a target of 2-APB in eggs, a condition that can be used to induce parthenogenesis. The association of endogenous TRPV3 channels with the actin cytoskeleton is a novel finding, and suggests that the rearrangements of actin that occur during maturation could regulate both plasma membrane presence and function of TRPV3 Ca2+ channels involved in oocyte maturation and fertilization. We show that TRPV3 is required for strontium influx because TRPV3-KO eggs failed to conduct Sr2+ or undergo strontium-induced activation. We propose that TRPV3 is a major mediator of calcium influx in mouse eggs and is a putative target for artificial egg activation. In chapter 3, we conducted studies to determine if expression of the testis-specific PLCZ1 correlated with low success or fertilization failure after ICSI in patients with normal parameters after standard semen analysis (SA). The presence of PLCZ1 in sperm was ascertained using western blotting and immunofluorescence (IF) analysis. The ability of sperm to initiate changes in the intracellular concentrations of [Ca2+]i was also examined. Male partners of couples with failed or low success ICSI fertilization but with normal SA parameters showed low expression levels of PLCZ1 as determined by western blotting and reduced fluorescent signal during IF studies. In addition, fewer of these males’ sperm showed PLCZ1 expression and were able to initiate robust [Ca2+]i oscillations upon injection into eggs. In the second part of this chapter, we examined two infertile brothers exhibiting normal sperm morphology but complete fertilization failure after intra cytoplasmic sperm injection (ICSI). Whole exomic sequencing evidenced a missense homozygous mutation in PLCZ1, converting Ile 489 into Phe (Ile489Phe). We showed that the mutation is deleterious, leading to absence of the protein in sperm. Injection of cRNA into GV and MII oocytes showed that the protein was mislocalized and produced highly abnormal Ca2+ transients and early embryonic arrest. Altogether these alterations are consistent with our patients’ sperm inability to induce oocyte activation and initiate embryo development. In contrast, no mutations were identified in WBP2NL and PAWP presented normal expression and localization. Overall we demonstrate in humans that the absence of PLCZ1 alone is sufficient to prevent oocyte activation irrespective of the presence of PAWP. Additionally, it is the first mutation located in the C2 domain of PLCZ1, a domain involved in targeting proteins to cell membranes, opening the door for structure function studies to define the conserved amino acids on the b1 strand of the C2 domain that might regulate the selectivity of PLCZ1 for its lipid substrate(s)

Airborne Measurements of High Pollutant Concentration Events in the Free Troposphere over the West Coast of South Korea between 1997 and 2011

Aircrafts enable the direct measurement of chemical components in the free troposphere (FT). This study employed airborne measurements to examine the occurrences of high concentrations of SO2 and NOx in the FT over the coastal region west of the Seoul metropolitan area, South Korea. The data from a long-term (1997-2011) airborne measurement campaign were used to determine the meteorological conditions favorable for carrying these pollutants into the Seoul area. The back trajectory analyses of 21 instances of high FT pollutant concentration events showed ascending patterns from the major pollutant sources, mainly the industrial complexes in eastern China, in 9 instances and passing patterns in 12 instances. In the ascending instances, developing low-pressure systems over the source regions provide favorable conditions to uplift air pollutants from the surface into the FT. In the passing instances, an anomalous low-pressure system near the surface prevented airflows from descending into the boundary layer and upper-level anticyclonic systems helped to keep the ascending airflows in the FT. This study proposes the basic mechanisms for predicting air quality in the Seoul area, considering that air pollutants in the FT often entrain into the boundary layer to increase local concentrationsopen0

Organic flexible memristor with reduced operating voltage and high stability by interfacial control of conductive filament growth

This work was supported in part through the BK21 Program funded by Ministry of Education of Korea.Herein, the underlying mechanisms for the growth of conductive filaments (CFs) at a metal–polymer electrolyte interface through ion migration in organic electrochemical metallization (ECM) memristor are presented. It is observed that the free volume of voids (nanopores) in the polymer electrolyte serves as the pathways of metal‐cations whereas the interfacial topography between an active electrode and a polymer electrolyte determines the nucleation sites of the CFs. The growth kinetics of the CFs and the resultant resistive memory are found to vary with the molecular weight of the polymer electrolyte and the metal protrusions at the interface. Our direct observations show that the free volume of voids of the polymer electrolyte, varied with the molecular weight, dictates the ion transport for the growth and the disruption of the CFs. Our organic ECM‐based memristor with a hetero‐electrolyte exhibits high mechanical flexibility, low switching voltages reduced by about three times compared to those of conventional devices, and stable memory retention for longer than 104 s under repeated cycles of bending.PostprintPeer reviewe

Industrialisasi Berbasis Pertanian sebagai Grand Stratedy Pembangunan Ekonomi Nasional

EnglishAs a developing economy Indonesia, should have a comprehensive integrated long-term development plan which may be used as the guideline in implementing its national economic development as well as an instrument for evaluating government accountability and credibility. The New Order regime had prepared its first and second long-term development plan for 1969-1993 and 1993-2018 successively. The twin plans, however, has led Indonesia to the 1997-1999 multi dimensions crises and is considered in appropriate in the existing new era of total reformation. It must be totally reconstructed. For this, public discussions on the need for the government to formulated the new grand strategy of national development have emerged, but up and down, in the last two years. As an active contribution to the public debase, this paper reviews previous, Indonesia development plans, others\u27 countries experiences as well as grand theories of economic development. Then it is suggested that the agricultural based industrialization may be the most suitable one for Indonesia. The new grand strategy should be decided based on a national concensus in order to avoid the practice of just for political rhetoric\u27s as was during the New Order regime. IndonesianBagi negara berkembang seperti Indonesia, rencana pembangunan jangka panjang komprehensif-integratif sangat di perlukan sebagai acuan pelaksanaan pembangunan dan sebagai salah satu instrumen akuntabilitas dan kredibilitas pemerintah. Pemerintahaan Orde Baru telah menyusun rancangan pembangunan jangka panjang tahap I dan II masing-masing untuk peiode 1969-1993 dan 1993-2018. Rencana jangka panjang yang disusun rejim Orde Baru tersebut terbukti membawa Indonesia kedalam krisis tahun 1997-1999 dan sudah tidak sesuai dalam era Reformasi sehingga perlu dirancang ulang. Dalam dua tahun terakhir sesungguhnya telah muncul wacana publik yang menuntut agar pemerintah segera menyusun grand strategy ( strategi besar ) pembangunan nasional. Sebagai bagian dari wacana tersebut, tulisan ini mereview tentang konsepsi strategi pembangunan selama Orde Baru, pengalaman beberapa negara lain pemikiran teoritis tentang strategi pembangunan ekonomi. Berdasarkan hasil review tersebut, disarankan agar industrialisasi berbasis pertanian (agricultural based industrialization) dijadikan sebagai strategi besar (grand strategy) pembangunan nasional. Strategi tersebut haruslah dijadikan sebagai konsensus nasional, sehingga tidak sekedar retorika politik seperti pada masa Orde Baru

TRPM7-like Channels are Functionally Expressed in Oocytes and Modulate Post-Fertilization Embryo Development in Mouse

The Transient Receptor Potential (TRP) channels are a family of cationic ion channels widely distributed in mammalian tissues. In general, the global genetic disruption of individual TRP channels result in phenotypes associated with impairment of a particular tissue and/or organ function. An exception is the genetic ablation of the TRP channel TRPM7, which results in early embryonic lethality. Nevertheless, the function of TRPM7 in oocytes, eggs and pre-implantation embryos remains unknown. Here, we described an outward rectifying non-selective current mediated by a TRP ion channel in immature oocytes (germinal vesicle stage), matured oocytes (metaphase II eggs) and 2-cell stage embryos. The current is activated by specific agonists and inhibited by distinct blockers consistent with the functional expression of TRPM7 channels. We demonstrated that the TRPM7-like channels are homo-tetramers and their activation mediates calcium influx in oocytes and eggs, which is fundamental to support fertilization and egg activation. Lastly, we showed that pharmacological inhibition of the channel function delays pre-implantation embryo development and reduces progression to the blastocyst stage. Our data demonstrate functional expression of TRPM7-like channels in mouse oocytes, eggs and embryos that may play an essential role in the initiation of embryo development

Statistics of Gravitational Microlensing Magnification. I. Two-Dimensional Lens Distribution

(Abridged) In this paper we refine the theory of microlensing for a planar distribution of point masses. We derive the macroimage magnification distribution P(A) at high magnification (A-1 >> tau^2) for a low optical depth (tau << 1) lens distribution by modeling the illumination pattern as a superposition of the patterns due to individual ``point mass plus weak shear'' lenses. We show that a point mass plus weak shear lens produces an astroid- shaped caustic and that the magnification cross-section obeys a simple scaling property. By convolving this cross-section with the shear distribution, we obtain a caustic-induced feature in P(A) which also exhibits a simple scaling property. This feature results in a 20% enhancement in P(A) at A approx 2/tau. In the low magnification (A-1 << 1) limit, the macroimage consists of a bright primary image and a large number of faint secondary images formed close to each of the point masses. Taking into account the correlations between the primary and secondary images, we derive P(A) for low A. The low-A distribution has a peak of amplitude ~ 1/tau^2 at A-1 ~ tau^2 and matches smoothly to the high-A distribution. We combine the high- and low-A results and obtain a practical semi-analytic expression for P(A). This semi-analytic distribution is in qualitative agreement with previous numerical results, but the latter show stronger caustic-induced features at moderate A for tau as small as 0.1. We resolve this discrepancy by re-examining the criterion for low optical depth. A simple argument shows that the fraction of caustics of individual lenses that merge with those of their neighbors is approx 1-exp(-8 tau). For tau=0.1, the fraction is surprisingly high: approx 55%. For the purpose of computing P(A) in the manner we did, low optical depth corresponds to tau << 1/8.Comment: 35 pages, including 6 figures; uses AASTeX v4.0 macros; submitted to Ap

Topography-Guided Spreading and Drying of 6,13-bis(triisopropylsilylethynyl)-pentacene Solution on a Polymer Insulator for the Field-Effect Mobility Enhancement

We report on the enhancement of the field-effect mobility of solution-processed 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-pentacene) by unidirectional topography (UT) of an inkjet-printed polymer insulator. The UT leads to anisotropic spreading and drying of the TIPS-pentacene droplet and enables to spontaneously develop the ordered structures during the solvent evaporation. The mobility of the UT-dictated TIPS-pentacene film (0.202 ± 0.012 cm2/Vs) is found to increase by more than a factor of two compared to that of the isotropic case (0.090 ± 0.032 cm2/Vs). The structural arrangement of the TIPS-pentacene molecules in relation to the mobility enhancement is described within an anisotropic wetting formalism. Our UT-based approach to the mobility enhancement is easily applicable to different classes of soluble organic field-effect transistors by adjusting the geometrical parameters such as the height, the width, and the periodicity of the UT of an inkjet-printed insulator

Indirect Band Gap in Scrolled MoS₂ Monolayers

MoS2 nanoscrolls that have inner core radii of similar to 250 nm are generated from MoS2 monolayers, and the optical and transport band gaps of the nanoscrolls are investigated. Photoluminescence spectroscopy reveals that a MoS2 monolayer, originally a direct gap semiconductor (similar to 1.85 eV (optical)), changes into an indirect gap semiconductor (similar to 1.6 eV) upon scrolling. The size of the indirect gap for the MoS2 nanoscroll is larger than that of a MoS2 bilayer (similar to 1.54 eV), implying a weaker interlayer interaction between concentric layers of the MoS2 nanoscroll compared to Bernal-stacked MoS2 few-layers. Transport measurements on MoS2 nanoscrolls incorporated into ambipolar ionic-liquid-gated transistors yielded a band gap of similar to 1.9 eV. The difference between the transport and optical gaps indicates an exciton binding energy of 0.3 eV for the MoS2 nanoscrolls. The rolling up of 2D atomic layers into nanoscrolls introduces a new type of quasi-1D nanostructure and provides another way to modify the band gap of 2D materials.11Nsciescopu