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Conditioned place preference (CPP) is a learned behavior, in which animals learn to associate environmental contexts with rewarding effects. The formation of CPP is an integrated outcome of multiple learning processes. Although multiple anatomical substrates underlying this contextual learning have been proposed, it remains unknown whether a specific molecular signaling pathway within CA1 mediates context learning associated with morphine conditioning. Here, we showed that repeated context learning associated with morphine conditioning significantly increased CXCL12 levels in hippocampal CA1 neurons, and the inhibition of CXCL12 expression ameliorated the CPP behavior following context exposure with morphine conditioning. Additionally, repeated context exposure with morphine conditioning increased the phosphorylation of STAT3 and the acetylation of histone H4 in CXCL12-expressing neurons in CA1. Immunoprecipitation and chromatin immunoprecipitation assays demonstrated that repeated context exposure with morphine conditioning increased the binding of STAT3 to the CXCL12 gene promoter and the interaction between STAT3 and p300, which contributed to the enhanced transcription of CXCL12 by increasing the acetylation of histone H4 in the CXCL12 gene promoter. The inhibition of STAT3 by intrathecal injection of S3I-201 suppressed the acetylation of histone H4. These data demonstrated the epigenetic upregulation of CXCL12 following repeated context exposure with morphine conditioning, which potentially contributed to the spatial memory consolidation associated with conditioned place preference induced by morphine conditioning.

In this study, we sequenced and analyzed the complete mitochondrial genome of Mansonia uniformis, and this is the first report on the genus Mansonia. The circular mitogenome is 15,603 bp long and c...

Previous studies have proved that waterlogging stress accelerates the programmed cell death (PCD) progress of wheat endosperm cells. A highly waterlogging-tolerant wheat cultivar Hua 8 and a waterlogging susceptible wheat cultivar Hua 9 were treated with different waterlogging durations, and then, dynamic changes of reactive oxygen species (ROS), gene expressions, and activities of antioxidant enzymes in endosperm cells were detected. The accumulation of ROS increased considerably after 7 days of waterlogging treatment (7 DWT) and 12 DWT in both cultivars compared with control group (under non-waterlogged conditions), culminated at 12 DAF (days after flowering) and reduced hereafter. Waterlogging resulted in a great increase of H2O2 and O2 (-) in plasma membranes, cell walls, mitochondrias, and intercellular spaces with ultracytochemical localization. Moreover, the deformation and rupture of cytomembranes as well as the swelling and distortion of mitochondria were obvious. Under waterlogging treatment conditions, catalase (CAT) gene expression increased in endosperm of Hua 8 but activity decreased. In addition, Mn superoxide dismutase (MnSOD) gene expression and superoxide dismutase (SOD) activity increased. Compared with Hua 8, both CAT, MnSOD gene expressions and CAT, SOD activities decreased in Hua 9. Moreover, ascorbic acid and mannitol relieve the intensifying of PCD processes in Hua 8 endosperm cells induced by waterlogging. These results indicate that ROS have important roles in the PCD of endosperm cells, the changes both CAT, MnSOD gene expressions and CAT, SOD activities directly affected the accumulation of ROS in two different wheat cultivars under waterlogging, ultimately led to the PCD acceleration of endosperm.

Autoimmune diseases often induce dysregulated hematopoiesis with altered number and function of hematopoietic stem and progenitor cells (HSPCs). However, there are limited studies on the direct regulation of HSPCs on T cells, which are often detrimental to autoimmunity. Here, we found that in a murine model of Concanavalin A-induced autoimmune hepatitis, LSK (Lineage−Sca-1+c-Kit+)-like cells accumulated in liver, spleen, and bone marrow (BM), which were myeloid progenitors (Lineage−Sca-1−c-Kit+) that upregulated Sca-1 expression upon T cell-derived IFN-γ stimulation. Strikingly, BM LSK-like cells from mice induced by Con A to develop autoimmune hepatitis or alternatively myeloid progenitors from wild-type mice possessed strong in vitro suppressive ability. Their suppressive function depended on T cell-derived IFN-γ in a paracrine fashion, which induced STAT1 phosphorylation, inducible nitric oxide synthase expression, and nitric oxide production. Blocking IFN-γ/IFN-γ receptor interaction, knockout of STAT1, or iNOS inhibition abrogated their suppressive function. In addition, the suppressive function was independent of differentiation; mitomycin C-treated myeloid progenitors maintained T cell suppressive ability in vitro. Our data demonstrate a mechanism of inflammation induced suppressive function of myeloid progenitors, which may participate directly in suppressing T cell-mediated immunopathology.

Summary In angiosperms, the first zygotic division usually gives rise to two daughter cells with distinct morphologies and developmental fates, which is critical for embryo pattern formation; however, it is still unclear when and how these distinct cell fates are specified, and whether the cell specification is related to cytoplasmic localization or polarity. Here, we demonstrated that when isolated from both maternal tissues and the apical cell, a single basal cell could only develop into a typical suspensor, but never into an embryo in vitro. Morphological, cytological and gene expression analyses confirmed that the resulting suspensor in vitro is highly similar to its undisturbed in vivo counterpart. We also demonstrated that the isolated apical cell could develop into a small globular embryo, both in vivo and in vitro, after artificial dysfunction of the basal cell; however, these growing apical cell lineages could never generate a new suspensor. These findings suggest that the initial round of cell fate specification occurs at the two-celled proembryo stage, and that the basal cell lineage is autonomously specified towards the suspensor, implying a polar distribution of cytoplasmic contents in the zygote. The cell fate transition of the basal cell lineage to the embryo in vivo is actually a conditional cell specification process, depending on the developmental signals from both the apical cell lineage and maternal tissues connected to the basal cell lineage.

The complete mitochondrial genome of Scatella tenuicosta has been reported in this study. This is the first sequenced complete mitogenome of the genus Scatella. Totally, 37 genes presented in the 1...

Although considerable progress has been made in identifying the genes regulating accumulation of hormones that are involved in leaf senescence, only a few studies have focused on natural variations in jasmonates content and much less on the underlying genetic basis. Moreover, the epigenetic regulation of jasmonate-mediated leaf senescence remains largely unknown. In this study, we carried out metabolic profiling of a worldwide collection of rice accessions and demonstrated that there are substantial variations in jasmonate levels among these accessions. A subsequent metabolite-based genome-wide association study identified candidates for two major quantitative genes (QTGs), OsPME1 and OsTSD2, affecting the content of jasmonates. Further investigations using a series of relevant mutants and transgenic lines revealed the MeOH-jasmonate cascade plays an important role in regulating leaf senescence. Moreover, we showed that OsSRT1, one of the two Sir2 (silent information regulator 2) homologs in rice, negatively regulates leaf senescence by repressing expression of the biosynthetic genes of this metabolic cascade and at least particially through histone H3K9 deacetylation of OsPME1. Taken together, our results indicate that the MeOH-jasmonates cascade and its epigenetic regulation are crucial for controlling leaf senescence process in rice.

The influence of low-temperature treatment of ovaries on the isolation and subsequent culture of two-celled proembryo in vitro was explored in tobacco. The efficiency of isolation of two-celled proembryos was significantly improved, by an average of 23.47 % after treatment of ovaries at 4°C for 5–24 h. Cell viability and polarity of two-celled proembryos, as assessed by organelle distribution, growth pattern, and cell wall component distribution, were all well maintained after cold treatment. Furthermore, in vitro cultivated two-celled proembryos divided normally, with timing paralleling that of two-celled proembryos isolated from fresh ovaries. Unexpectedly, the division frequency of two-celled proembryos was significantly improved by cold treatment. These results demonstrate that low-temperature treatment of tobacco ovaries was beneficial for two-celled proembryo manipulation in vitro, by not only improving isolation efficiency but also by promoting cell division and improving the potential for further cultivation.

Gene expression profiling by quantitative real-time PCR (RT-qPCR) is a valuable tool in forensic science for estimating the age of a wound. To accurately assess gene expression levels over time in injured tissue, the genes used as internal reference standards must be carefully validated for transcriptional stability. This study examined the transcriptional stability of nine potential reference genes (β-actin, GAPDH, RPL32, PGK1, SDHA, RPL13, HPRT, Tbp, and Ywhaz) in contused rat skeletal muscle by RT-qPCR. The raw Ct values were determined for each candidate gene at different time points following contusion, and the data were analyzed by the NormFinder, geNorm, and BestKeeper validation programs. The reference genes RPL13 and RPL32 were the most stably expressed genes in contused skeletal muscle, whereas PGK1 was the least stable. The commonly used reference genes β-actin and GAPDH appeared to be too unstable for normalization of RT-qPCR expression profiling in contused muscle. The reference genes RPL13 and RPL32 were also the best combination for multianalysis. The use of RPL13 and RPL32 as internal standards may improve the accuracy of gene expression studies aimed at determining the age of early wounds in forensic investigations.

The maternal-to-zygotic transition (MZT) is characterized by the turnover of zygote development from maternal to zygotic control, and has been extensively studied in animals. A majority of studies have suggested that early embryogenesis is maternally controlled and that the zygotic genome remains transcriptionally inactive prior to the MZT. However, little is known about the MZT in higher plants, and its timing and impact remain uncharacterized. Here, we constructed cDNA libraries from tobacco (Nicotiana tabacum) egg cells, zygotes and two-celled embryos for gene expression profiling analysis, followed by RT-PCR confirmation. These analyses, together with experiments using zygote microculture coupled with transcription inhibition, revealed that a marked change in transcript profiles occurs approximately 50 h after fertilization, and that the MZT is initiated prior to zygotic division in tobacco. Although maternal transcripts deposited in egg cells support several early developmental processes, they appear to be insufficient for zygotic polar growth and subsequent cell divisions. Thus, we propose that de novo transcripts are probably required to trigger embryogenesis in later zygotes in tobacco.

A climate-controlled greenhouse experiment was conducted to determine the influence of soil water stress on the nutrient status of a climbing plant, Parthenocissus tricuspidata ( Sieb.et Zucc ) Planch . The results showed that water stress constrained N uptake more than P and K uptake in P. tricuspidata . Soil water supply significantly affected N efficiency ratio, but had no effect on P and K efficiency ratios. P. tricuspidata had low K concentration ( −1 ) in all its plant tissues, which allowed the plant to limit its stomatal opening and reduce its water loss. The study revealed that P. tricuspidata is able to adjust biomass distribution, nutrient uptake and nutrient use efficiency in response to soil water stress and that nutrient management for this plant under water stress should focus on N more than on P and K.

A method of vegetation establishment with rocky slopes was conducted by planting three climbing plant species ( Parthenocissus tricuspidata ( Sieb.et Zucc ) Planch , Hedera helix and Euonymus fortunei ( f. minimus )) an artificial hole drilled on a rocky slope surface of an abandoned quarry. During the experiment period for 18 months, plant growth and dynamics of soil moisture content in holes were surveyed. The results indicated that artificial holes may save soil on the rocky slope for plant growth, but water deficit was the key limiting factor to plant growth in the hot summer. P. tricuspidata and E. fortunei had higher survival and growth rates than H. helix . They showed good adaptability to the disadvantageous growing conditions of rocky slope. The experiment demonstrated that P. tricuspidata and E. fortunei could be used as pioneer plant species for revegetation of rocky slopes.

A convenient experimental system was established to test how cells derived from higher-plant internal tissues respond to mechanical stimulation. Short-term culture of tobacco ovules in vitro led to the generation of bar-shaped cells from the parenchyma tissue of the ovule funicle. These cells are still connected to the mother tissue and are almost undifferentiated. The cells are translucent, and one end protrudes from the funicle, making them easy to manipulate and observe. Mechanical stimulation tests performed on these cells indicated that the cells are less sensitive to mechanical stimulation than epidermal hair cells but still possess the ability to respond to stimulation. Interestingly, the cells showed a cytoplasmic compartmental response to the stimulation. The nucleus, some plastids, and mitochondria were organized into a responsive unit that moved in unison to the stimulated sites, whereas most of the other organelles were not notably influenced by the stimulation. This suggests that the cytoplasm is highly organized and functionally divided in response to environmental stimulation.

It has been reported that vascular endothelial growth factor receptor 3 (VEGFR-3) is highly expressed in most tumor tissues, including gastric cancer. However, the effects of VEGFR-3 knockdown on the proliferation, apoptosis and invasion of gastric cancer cells and downstream signaling molecules have not yet been well established. In the present study, four short hairpin RNA (shRNA) sequences targeting the VEGFR-3 gene (NM_002020) were designed and cloned into a lentiviral vector, pRNAT-U6.2/Lenti, to construct four recombinant lentiviral vectors. The vectors with the two highest interfering efficiencies were selected to be co-transfected with packaging vectors in HEK293T cells to assemble lentivirus particles. Results from Western blot analysis showed that the VEGFR-3 shRNA-4 lentivirus-infected group (sh#4) had the highest efficiency of gene silencing in the MKN45 cell line compared with the parental and control group. The sh#4 group significantly slowed cell proliferation, decreased the mean percentage of S-phase cells and increased the mean percentage of G1 phase cells, promoted cell apoptosis, and also significantly inhibited cell invasion of MKN45 compared with the other two groups. Furthermore, the expression of the anti-apoptotic factor Bcl-2 was significantly decreased in the sh#4 group compared to that of the other two groups. Moreover, results from qRT-PCR revealed that knockdown of VEGFR-3 with the shRNA lentiviral vector resulted in down-regulation of the downstream neural cell adhesion molecule contactin-1 (CNTN-1). In conclusion, the recombinant lentivirus particles were able to remarkably suppress VEGFR-3 expression, regulate the cell cycle, inhibit proliferation and induce apoptosis in the MKN45 cell lines.

Background In animals, early embryonic development is largely dependent on maternal transcripts synthesized during gametogenesis. However, in higher plants, the extent of maternal control over zygote development and early embryogenesis is not fully understood yet. Nothing is known about the activity of the parental genomes during seed formation of interspecies hybrids. Methodology/Principal Findings Here, we report that an interspecies hybridization system between SR1 (Nicotiana tabacum) and Hamayan (N. rustica) has been successfully established. Based on the system we selected 58 genes that have polymorphic sites between SR1 and Hamayan, and analyzed the allele-specific expression of 28 genes in their hybrid zygotes (Hamayan x SR1). Finally the allele-specific expressions of 8 genes in hybrid zygotes were repeatedly confirmed. Among them, 4 genes were of paternal origin, 1 gene was of maternal origin and 3 genes were of biparental origin. These results revealed obvious biparental involvement and differentially contribution of parental-origin genes to zygote development in the interspecies hybrid. We further detected the expression pattern of the genes at 8-celled embryo stage found that the involvement of the parental-origin genes may change at different stages of embryogenesis. Conclusions/Significance We reveal that genes of both parental origins are differentially involved in early embryogenesis of a tobacco interspecies hybrid and functions in a developmental stage-dependent manner. This finding may open a window to seek for the possible molecular mechanism of hybrid vigor.

BACKGROUND: Asymmetric zygotic division in higher plants results in the formation of an apical cell and a basal cell. These two embryonic cells possess distinct morphologies and cell developmental fates. It has been proposed that unevenly distributed cell fate determinants and/or distinct cell transcript profiles may be the underlying reason for their distinct fates. However, neither of these hypotheses has convincing support due to technical limitations. METHODOLOGY/PRINCIPAL FINDINGS: Using laser-controlled microdissection, we isolated apical and basal cells and constructed cell type-specific cDNA libraries. Transcript profile analysis revealed difference in transcript composition. PCR and qPCR analysis confirmed that transcripts of selected embryogenesis-related genes were cell-type preferentially distributed. Some of the transcripts that existed in zygotes were found distinctly existed in apical or basal cells. The cell type specific de novo transcription was also found after zygotic cell division. CONCLUSIONS/SIGNIFICANCE: Thus, we found that the transcript diversity occurs between apical and basal cells. Asymmetric zygotic division results in the uneven distribution of some embryogenesis related transcripts in the two-celled proembryos, suggesting that a differential distribution of some specific transcripts in the apical or basal cells may involve in guiding the two cell types to different developmental destinies.

In addition to the mechanical forces of the external environment, the individual plant cell is also subject to multiple subtle biophysical forces that arise from neighboring cell growth and division within the tissue. To maintain a normal cell shape and division pattern, the plant cell is proposed to have the ability to sense and respond to repetitive subtle mechanical stimulations via nuclear-directed migration. It has been demonstrated that the nucleus is alert and highly sensitive to repetitive mechanical stimulations. Furthermore, the cytoplasm reacts to local mechanical stimulation in a compartmentalized fashion. The nucleus therefore plays a role as a chief organizer and active defender in response to mechanical stimulation. This finding provides new insight on the role of mechanical stimulation in regulating cell division and the consequent spatial positioning and shape of cells inside tissues. The finding also revealed that it necessitates further study into the reason for cytoplasmic functional compartmentalization in response to simulation in the context of cell evolution.

When mechanical stimulation is applied to a plant cell, the nucleus usually shows oriented movement to the site of stimulation (as a defensive response). Former researchers have revealed that applying mechanical pressure to plant tissues could line up cell division plane. A proposal, therefore, was put forward that cells inside plant tissue could receive mechanical signals from their growing neighbors to adjust their nuclear position and thus regulate the orientation of their dividing plane in order to form characteristic morphology of plant organs. To explore nuclear capacity and sensitivity to rapidly changing signals, multiple mechanical stimulations were applied to the same plant cell at intervals, either locally or at distance. The results revealed that the nucleus was highly sensitive to mechanical stimulations. It responded quickly to both local and distant stimulation by showing oriented movement toward the stimulation site. The nucleus was able to respond immediately to a second stimulation (no time lag) by starting up a second oriented movement toward the new signal; the completion of nuclear oriented movement to a first site of stimulation was not necessary for startup of a subsequent movement track to a second stimulation site, regardless of whether the second stimulation was applied ahead of or behind the moving nucleus. The nucleus responded to a second stimulation without loss of velocity, whether or not it was in a resting or moving state. This novel finding favors the proposal that growing tissues adjust the location of nuclei in cells by varying mechanical pressures; they thus control cell division according to a plan whereby organs and their constituent tissues develop in an orderly, specified manner. It appears that the enhanced sensitivity of plant cells to mechanical pressure is necessary not only in response to the external environment, but also to the developmental microenvironment inside the tissues.

Changes in ribosome population, RNA species and DNA composition in flower buds of apples (Malus pumila Mill. cvs Ralls and White winter pearmain) were investigated during breaking of dormancy and development. After bursting of flower buds, total ribosomes increased approximately 4-fold, and the polyribosomal fraction increased from 66% to 94% of total ribosomes. The newly synthesized ribosomes were identified by incorporation of radioactive precursor. The observed decrease in specific radioactivity of the monoribosomes is caused by the recruitment of monoribo-somes into polyribosomes after breaking of dormancy. In both cultivars, the 25S and 18S rRNA peaks increased to a high level on April 8. The peaks of low molecular weight RNA were apparently increased after initial swelling of the flower buds. The DNA of flower buds was separated into three bands by electrophoresis. The median band is the main band of nuclear DNAs. The ahead band and the slow-moving band are satellite components of nuclear DNAs, and they obviously rose after initial swelling of the flower buds. On April 8, when the flower buds had opened, two other small DNA bands could be detected. These results suggest that the changes in level of different ribosome populations, RNA species and DNA composition are related to dormancy breaking development of apple flower buds.

We applied suppression subtractive hybridization and mirror orientation selection to compare gene expression profiles of isolated Nicotiana tabacum cv SR1 zygotes and egg cells. Our results revealed that many differentially expressed genes in zygotes were transcribed de novo after fertilization. Some of these genes are critical to zygote polarity and pattern formation during early embryogenesis. This suggests that the transcriptome is restructed in zygote and that the maternal-to-zygotic transition happens before the first zygotic division, which is much earlier in higher plants than in animals. The expressed sequence tags used in this study provide a valuable resource for future research on fertilization and early embryogenesis.

Funder: European Union’s Horizon 2020 Marie Skłodowska – Curie Innovative Training Networks (ITN - ETN) under grant agreement No.: 675712European Union’s Horizon 2020 Marie Skłodowska – Curie Innovative Training Networks (ITN - ETN) under grant agreement No.: 675712 Czech Science Foundation (GA CR), junior project no. 19-23424Y MEYS CZ project CEITEC 2020 (LQ1601), Funder: MEYS CZ project CEITEC 2020 (LQ1601) NCMG research infrastructure (LM22018132 funded by MEYS CR), Funder: European Union’s Horizon 2020 Marie Skłodowska – Curie Innovative Training Networks (ITN - ETN) under grant agreement No.: 675712., Funder: MH CZ-RVO 65269705