Tracing blastomere fate choices of early embryos in single cell culture

Blastomeres of early vertebrate embryos undergo numerous fate choices for division, motility, pluripotency maintenance and restriction culminating in various cell lineages. Tracing blastomere fate choices at the single cell level in vitro has not been possible because of the inability to isolate and cultivate early blastomeres as single cells. Here we report the establishment of single cell culture system in the fish medaka, enabling the isolation and cultivation of individual blastomeres from 16- to 64-cell embryos for fate tracing at the single cell level in vitro. Interestingly, these blastomeres immediately upon isolation exhibit motility, lose synchronous divisions and even stop dividing in ≥50% cases, suggesting that the widely accepted nucleocytoplasmic ratio controlling synchronous divisions in entire embryos does not operate on individual blastomeres. We even observed abortive division, endomitosis and cell fusion. Strikingly, ~5% of blastomeres in single cell culture generated extraembryonic yolk syncytial cells, embryonic stem cells and neural crest-derived pigment cells with timings mimicking their appearance in embryos. We revealed the maternal inheritance of key lineage regulators and their differential expression in cleavage embryos. Therefore, medaka blastomeres possess the accessibility for single cell culture, previously unidentified heterogeneity in motility, division, gene expression and intrinsic ability to generate major extraembryonic and embryonic lineages without positioning cues. Our data demonstrate the fidelity and potential of the single cell culture system for tracking blastomere fate decisions under defined conditions in vitro

Transient and Stable GFP Expression in Germ Cells by the vasa Regulatory Sequences from the Red Seabream (Pagrus major)

Primordial germ cells (PGCs) are the precursors of gametes responsible for genetic transmission to the next generation. They provide an ideal system for cryopreservation and restoration of biodiversity. Recently, considerable attention has been raised to visualize, isolate and transplant PGCs within and between species. In fish, stable PGC visualization in live embryo and individual has been limited to laboratory fish models such as medaka and zebrafish. One exception is the rainbow trout, which represents the only species with aquaculture importance and has GFP-labeled germ cells throughout development. PGCs can be transiently labeled by embryonic injection of mRNA containing green fluorescence protein gene (GFP) and 3'-untranslated region (3'-UTR) of a maternal germ gene such as vasa, nos1, etc. Stable PGC labeling can be achieved through production of transgenic animals by some transcriptional regulatory sequences from germ genes, such as the vasa promoter and 3'-UTR. In this study, we reported the functional analyses of the red seabream vasa (Pmvas) regulatory sequences, using medaka as a model system. It was showed that injection of GFP-Pmvas3'UTR mRNA was able to label medaka PGCs during embryogenesis. Besides, we have constructed pPmvasGFP transgenic vector, and established a stable transgenic medaka line exhibiting GFP expression in germ cells including PGCs, mitotic and meiotic germ cells of both sexes, under control of the Pmvas transcriptional regulatory sequences. It is concluded that the Pmvas regulatory sequences examined in this study are sufficient for germ cell expression and labeling

Construction of stable Ta3N5/g-C3N4 metal/non-metal nitride hybrids with enhanced visible-light photocatalysis

In this paper, a novel Ta3N5/g-C3N4 metal/non-metal nitride hybrid was successfully synthesized by a facile impregnation method. The photocatalytic activity of Ta3N5/g-C3N4 hybrid nitrides was evaluated by the degradation of organic dye rhodamine B (RhB) under visible light irradiation, and the result indicated that all Ta3N5/g-C3N4 samples exhibited distinctly enhanced photocatalytic activities for the degradation of RhB than pure g-C3N4. The optimal Ta3N5/g-C3N4 composite sample, with Ta3N5 mass ratio of 2%, demonstrated the highest photocatalytic activity, and its degradation rate constant was 2.71 times as high as that of pure g-C3N4. The enhanced photocatalytic activity of this Ta3N5/g-C3N4 metal/metal-free nitride was predominantly attributed to the synergistic effect which increased visible-light absorption and facilitated the efficient separation of photoinduced electrons and holes. The Ta3N5/g-C3N4 hybrid nitride exhibited excellent photostability and reusability. The possible mechanism for improved photocatalytic performance was proposed. Overall, this work may provide a facile way to synthesize the highly efficient metal/metal-free hybrid nitride photocatalysts with promising applications in environmental purification and energy conversion

High-density lipoprotein cholesterol level as an independent protective factor against aggravation of acute pancreatitis: a case–control study

Background and aimsAt present, evidence on the association between high-density lipoprotein cholesterol (HDL-C) levels and aggravation of acute pancreatitis (AP) is limited. This study aimed to investigate the relationship between the lowest HDL-C level during intensive care units (ICU) stay and AP aggravation and to determine the optimum cutoff lowest HDL-C level.MethodsPatients admitted to the ICU of the Shandong Provincial Hospital for AP from 2015 to 2021 were included. The lowest HDL-C level during ICU stay was set as the independent variable, and the progression or non-progression to severe AP (SAP) was set as the dependent variable. Univariate and multivariate analyses were performed to determine the relationship between the two variables, and receiver operating characteristic (ROC) curves were plotted to analyze the predictive ability of the lowest HDL-C level for progression to SAP.ResultsThis study included 115 patients. The difference in the lowest HDL-C level between the SAP and moderately SAP groups was significant (P < 0.05). After adjusting for covariates, the lowest HDL-C level showed a negative correlation with the occurrence of SAP, with a relative risk of 0.897 (95% confidence interval: 0.827–0.973). The area under the ROC curve for prediction of AP aggravation by the lowest HDL-C level was 0.707, and the optimum cutoff lowest HDL-C level was 0.545 mmol/L.ConclusionNo less than 0.545 mmol/L of the HDL-C level during ICU stay may be an independent protective factor for the aggravation of AP

4,4′-Bis(2,2-diphenyl­vin­yl)-1,1′-biphen­yl

The title mol­ecule, C40H30, lies on an inversion center. The two unique phenyl rings form dihedral angles of 51.98 (8) and 67.58 (8)° with the essentially planar biphenyl unit [maximum deviation = 0.0360 (14) Å]

Gene Expression and Regulation of Higher Plants Under Soil Water Stress

Higher plants not only provide human beings renewable food, building materials and energy, but also play the most important role in keeping a stable environment on earth. Plants differ from animals in many aspects, but the important is that plants are more easily influenced by environment than animals. Plants have a series of fine mechanisms for responding to environmental changes, which has been established during their long-period evolution and artificial domestication. The machinery related to molecular biology is the most important basis. The elucidation of it will extremely and purposefully promote the sustainable utilization of plant resources and make the best use of its current potential under different scales. This molecular mechanism at least includes drought signal recognition (input), signal transduction (many cascade biochemical reactions are involved in this process), signal output, signal responses and phenotype realization, which is a multi-dimension network system and contains many levels of gene expression and regulation. We will focus on the physiological and molecular adaptive machinery of plants under soil water stress and draw a possible blueprint for it. Meanwhile, the issues and perspectives are also discussed. We conclude that biological measures is the basic solution to solving various types of issues in relation to sustainable development and the plant measures is the eventual way

Study on volatilization characteristic of vanadium and tungsten of vanadium-based selective catalytic reduction

Vanadium-based selective catalyst reduction (V-SCR) has made significant contributions to De-NOx of diesel vehicles. However, the two main catalyst components, V2O5 and WO3, are volatile and toxic. Therefore, there are some restrictions for its application on heavy duty diesel vehicles (HDDV) in the CHINA VI stage. In view of this problem, the volatilization rates of two kinds of volatiles under different inlet temperature and test duration were measured on three V-SCR samples from different catalyst manufacturers. The effects of V-SCR inlet temperature and test duration on the volatilization characteristics of the two volatiles on different samples were systematically studied and compared. The emission concentrations of V2O5 and WO3 at different temperatures were compared with the occupational exposure limits of chemical harmful factors in the workplace which is specified in the GBZ 2.1-2019. The results show that the initial temperature of volatilization of V-SCR is directly related to the technical level of the catalyst itself; whether the volatilization characteristics of V-SCR will change with the prolongation of test duration depends on its inlet temperature; V2O5 emission concentration of V-SCR at 550 C° can reach a quite high exposure level, and the exposure level of WO3 volatiles at 650 C° may be equivalent to that of V2O5 volatiles at 550 C°

Identification of Pluripotency Genes in the Fish Medaka

Stem cell cultures can be derived directly from early developing embryos and indirectly from differentiated cells by forced expression of pluripotency transcription factors. Pluripotency genes are routinely used to characterize mammalian stem cell cultures at the molecular level. However, such genes have remained unknown in lower vertebrates. In this regard, the laboratory fish medaka is uniquely suited because it has embryonic stem (ES) cells and genome sequence data. We identified seven medaka pluripotency genes by homology search and expression in vivo and in vitro. By RT-PCR analysis, the seven genes fall into three groups of expression pattern. Group I includes nanog and oct4 showing gonad-specific expression; Group II contains sall4 and zfp281 displaying gonad-preferential expression; Group III has klf4, ronin and tcf3 exhibiting expression also in several somatic tissues apart from the gonads. The transcripts of the seven genes are maternally supplied and persist at a high level during early embryogenesis. We made use of early embryos and adult gonads to examine expression in stem cells and differentiated derivatives by in situ hybridization. Strikingly, nanog and oct4 are highly expressed in pluripotent blastomeres of 16-cell embryos. In the adult testis, nanog expression was specific to spermatogonia, the germ stem cells, whereas tcf3 expression occurred in spermatogonia and differentiated cells. Most importantly, all the seven genes are pluripotency markers in vitro, because they have high expression in undifferentiated ES cells but dramatic down-regulation upon differentiation. Therefore, these genes have conserved their pluripotency-specific expression in vitro from mammals to lower vertebrates

Colorless and Transparent high – Temperature-Resistant Polymer Optical Films – Current Status and Potential Applications in Optoelectronic Fabrications

Recent research and development of colorless and transparent high-temperature-resistant polymer optical films (CHTPFs) have been reviewed. CHTPF films possess the merits of both common polymer optical film and aromatic high-temperature-resistant polymer films and thus have been widely investigated as components for microelectronic and optoelectronic fabrications. The current paper reviews the latest research and development for CHTPF films, including their synthesis chemistry, manufacturing process, and engineering applications. Especially, this review focuses on the applications of CHTPF films as flexible substrates for optoelectrical devices, such as flexible active matrix organic light-emitting display devices (AMOLEDs), flexible printing circuit boards (FPCBs), and flexible solar cells