CDS-DB, an omnibus for patient-derived gene expression signatures induced by cancer treatment.

Patient-derived gene expression signatures induced by cancer treatment, obtained from paired pre- and post-treatment clinical transcriptomes, can help reveal drug mechanisms of action (MOAs) in cancer patients and understand the molecular response mechanism of tumor sensitivity or resistance. Their integration and reuse may bring new insights. Paired pre- and post-treatment clinical transcriptomic data are rapidly accumulating. However, a lack of systematic collection makes data access, integration, and reuse challenging. We therefore present the Cancer Drug-induced gene expression Signature DataBase (CDS-DB). CDS-DB has collected 78 patient-derived, paired pre- and post-treatment transcriptomic source datasets with uniformly reprocessed expression profiles and manually curated metadata such as drug administration dosage, sampling time and location, and intrinsic drug response status. From these source datasets, 2012 patient-level gene perturbation signatures were obtained, covering 85 therapeutic regimens, 39 cancer subtypes and 3628 patient samples. Besides data browsing, download and search, CDS-DB also supports single signature analysis (including differential gene expression, functional enrichment, tumor microenvironment and correlation analyses), signature comparative analysis and signature connectivity analysis. This provides insights into drug MOA and its heterogeneity in patients, drug resistance mechanisms, drug repositioning and drug (combination) discovery, etc. CDS-DB is available at http://cdsdb.ncpsb.org.cn/.

Stage-specific regulation of undifferentiated spermatogonia by AKT1S1-mediated AKT-mTORC1 signaling during mouse spermatogenesis.

Undifferentiated spermatogonia are composed of a heterogeneous cell population including spermatogonial stem cells (SSCs). Molecular mechanisms underlying the regulation of various spermatogonial cohorts during their self-renewal and differentiation are largely unclear. Here we show that AKT1S1, an AKT substrate and inhibitor of mTORC1, regulates the homeostasis of undifferentiated spermatogonia. Although deletion of Akt1s1 in mouse appears not grossly affecting steady-state spermatogenesis and male mice are fertile, the subset of differentiation-primed OCT4+ spermatogonia decreased significantly, whereas self-renewing GFRα1+ and proliferating PLZF+ spermatogonia were sustained. Both neonatal prospermatogonia and the first wave spermatogenesis were greatly reduced in Akt1s1-/- mice. Further analyses suggest that OCT4+ spermatogonia in Akt1s1-/- mice possess altered PI3K/AKT-mTORC1 signaling, gene expression and carbohydrate metabolism, leading to their functionally compromised developmental potential. Collectively, these results revealed an important role of AKT1S1 in mediating the stage-specific signals that regulate the self-renewal and differentiation of spermatogonia during mouse spermatogenesis.

Research progress on prediction of RNA-protein binding sites in the past five years.

Accurately predicting RNA-protein binding sites is essential to gain a deeper comprehension of the protein-RNA interactions and their regulatory mechanisms, which are fundamental in gene expression and regulation. However, conventional biological approaches to detect these sites are often costly and time-consuming. In contrast, computational methods for predicting RNA protein binding sites are both cost-effective and expeditious. This review synthesizes already existing computational methods, summarizing commonly used databases for predicting RNA protein binding sites. In addition, applications and innovations of computational methods using traditional machine learning and deep learning for RNA protein binding site prediction during 2018-2023 are presented. These methods cover a wide range of aspects such as effective database utilization, feature selection and encoding, innovative classification algorithms, and evaluation strategies. Exploring the limitations of existing computational methods, this paper delves into the potential directions for future development. DeepRKE, RDense, and DeepDW all employ convolutional neural networks and long and short-term memory networks to construct prediction models, yet their algorithm design and feature encoding differ, resulting in diverse prediction performances.

Progress of Ferroptosis in Ischemic Stroke and Therapeutic Targets.

Ferroptosis is an iron-dependent form of programmed cell death (PCD) and ischemic stroke (IS) has been confirmed to be closely related to ferroptosis. The mechanisms of ferroptosis were summarized into three interrelated aspects: iron metabolism, lipid peroxide metabolism, as well as glutathione and amino acid metabolism. What's more, the causal relationship between ferroptosis and IS has been elucidated by several processes. The disruption of the blood-brain barrier, the release of excitatory amino acids, and the inflammatory response after ischemic stroke all lead to the disorder of iron metabolism and the antioxidant system. Based on these statements, we reviewed the reported effects of compounds and drugs treating IS by modulating key molecules in ferroptosis. Through detailed analysis of the roles of these key molecules, we have also more clearly demonstrated the essential effect of ferroptosis in the occurrence of IS so as to provide new targets and ideas for the therapeutic targets of IS.

Progress of Astrocyte-Neuron Crosstalk in Central Nervous System Diseases.

Neurons are the primary cells responsible for information processing in the central nervous system (CNS). However, they are vulnerable to damage and insult in a variety of neurological disorders. As the most abundant glial cells in the brain, astrocytes provide crucial support to neurons and participate in synapse formation, synaptic transmission, neurotransmitter recycling, regulation of metabolic processes, and the maintenance of the blood-brain barrier integrity. Though astrocytes play a significant role in the manifestation of injury and disease, they do not work in isolation. Cellular interactions between astrocytes and neurons are essential for maintaining the homeostasis of the CNS under both physiological and pathological conditions. In this review, we explore the diverse interactions between astrocytes and neurons under physiological conditions, including the exchange of neurotrophic factors, gliotransmitters, and energy substrates, and different CNS diseases such as Alzheimer's disease, Parkinson's disease, stroke, traumatic brain injury, and multiple sclerosis. This review sheds light on the contribution of astrocyte-neuron crosstalk to the progression of neurological diseases to provide potential therapeutic targets for the treatment of neurological diseases.

CTR-DB, an omnibus for patient-derived gene expression signatures correlated with cancer drug response.

To date, only some cancer patients can benefit from chemotherapy and targeted therapy. Drug resistance continues to be a major and challenging problem facing current cancer research. Rapidly accumulated patient-derived clinical transcriptomic data with cancer drug response bring opportunities for exploring molecular determinants of drug response, but meanwhile pose challenges for data management, integration, and reuse. Here we present the Cancer Treatment Response gene signature DataBase (CTR-DB, http://ctrdb.ncpsb.org.cn/), a unique database for basic and clinical researchers to access, integrate, and reuse clinical transcriptomes with cancer drug response. CTR-DB has collected and uniformly reprocessed 83 patient-derived pre-treatment transcriptomic source datasets with manually curated cancer drug response information, involving 28 histological cancer types, 123 drugs, and 5139 patient samples. These data are browsable, searchable, and downloadable. Moreover, CTR-DB supports single-dataset exploration (including differential gene expression, receiver operating characteristic curve, functional enrichment, sensitizing drug search, and tumor microenvironment analyses), and multiple-dataset combination and comparison, as well as biomarker validation function, which provide insights into the drug resistance mechanism, predictive biomarker discovery and validation, drug combination, and resistance mechanism heterogeneity.

Transcriptomic and epigenomic profiling of young and aged spermatogonial stem cells reveals molecular targets regulating differentiation.

Spermatogonial stem cells (SSC), the foundation of spermatogenesis and male fertility, possess lifelong self-renewal activity. Aging leads to the decline in stem cell function and increased risk of paternal age-related genetic diseases. In the present study, we performed a comparative genomic analysis of mouse SSC-enriched undifferentiated spermatogonia (Oct4-GFP+/KIT-) and differentiating progenitors (Oct4-GFP+/KIT+) isolated from young and aged testes. Our transcriptome data revealed enormous complexity of expressed coding and non-coding RNAs and alternative splicing regulation during SSC differentiation. Further comparison between young and aged undifferentiated spermatogonia suggested these differentiation programs were affected by aging. We identified aberrant expression of genes associated with meiosis and TGF-ß signaling, alteration in alternative splicing regulation and differential expression of specific lncRNAs such as Fendrr. Epigenetic profiling revealed reduced H3K27me3 deposition at numerous pro-differentiation genes during SSC differentiation as well as aberrant H3K27me3 distribution at genes in Wnt and TGF-ß signaling upon aging. Finally, aged undifferentiated spermatogonia exhibited gene body hypomethylation, which is accompanied by an elevated 5hmC level. We believe this in-depth molecular analysis will serve as a reference for future analysis of SSC aging.

Expression analysis and targets prediction of microRNAs in OGD/R treated astrocyte-derived exosomes by smallRNA sequencing.

Astrocytes activate and crosstalk with neurons influencing inflammatory responses following ischemic stroke. The distribution, abundance, and activity of microRNAs in astrocytes-derived exosomes after ischemic stroke remains largely unknown. In this study, exosomes were extracted from primary cultured mouse astrocytes via ultracentrifugation, and exposed to oxygen glucose deprivation/re­oxygenation injury to mimic experimental ischemic stroke. SmallRNAs from astrocyte-derived exosomes were sequenced, and differentially expressed microRNAs were randomly selected and verified by stem-loop real time quantitative polymerase chain reaction. We found that 176 microRNAs, including 148 known and 28 novel microRNAs, were differentially expressed in astrocyte-derived exosomes following oxygen glucose deprivation/re­oxygenation injury. In gene ontology enrichment, Kyoto encyclopedia of genes and genomes pathway analyses, and microRNA target gene prediction analyses, these alteration in microRNAs were associated to a broad spectrum of physiological functions including signaling transduction, neuroprotection and stress responses. Our findings warrant further investigating of these differentially expressed microRNAs in human diseases particularly ischemic stroke.

Lack of AKAP3 disrupts integrity of the subcellular structure and proteome of mouse sperm and causes male sterility.

The development and maintenance of the correct morphology of sperm is important for their functions. Cellular morphogenesis of sperm occurs during the post-meiotic developmental stage; however, little is known about what coordinates this process. In the present study, we investigated the role of A-kinase anchoring protein 3 (AKAP3) during mouse spermiogenesis, using both mouse genetics and proteomics. It was found that AKAP3 is essential for the formation of the specific subcellular structure of the sperm flagellum, motility of sperm and male fertility. Additionally, lack of AKAP3 caused global changes of the sperm proteome and mislocalization of sperm proteins, including accumulation of RNA metabolism and translation factors and displacement of PKA subunits in mature sperm, which may underlie misregulated PKA activity and immotility in sperm. Interestingly, sperm lacking a complete fibrous sheath from both Akap3 and Akap4 null mice accumulated F-actin filaments and morphological defects during post-testicular maturation in the epididymis. These results suggest that the subcellular structures of sperm could be formed via independent pathways, and elucidate the roles of AKAP3 during the coordinated synthesis and organization of the sperm proteome and sperm morphology.

Selenium-integrated conjugated oligomer nanoparticles with high photothermal conversion efficiency for NIR-II imaging-guided cancer phototheranostics in vivo.

Second near-infrared (NIR-II) fluorescence imaging in the range of 1000-1700 nm has great prospects for in vivo imaging and theranostics monitoring. At present, few NIR-II probes with theranostics properties have been developed, especially the high-performance organic theranostics material remains underexploited. Herein, we demonstrate a selenium (Se)-tailoring method to develop high-efficient NIR-II imaging-guided material for in vivo cancer phototheranostics. Via Se-tailoring strategy, conjugated oligomer TPSe-based nanoparticles (TPSe NPs) achieve bright NIR-II emission up to 1400 nm and exhibit a relatively high photothermal conversion efficiency of 60% with good stability. Moreover, the TPSe NPs demonstrate their photothermal ablation of cancer cells in vitro and tumor in vivo with the guidance of NIR-II imaging. It is worth noting that the TPSe NPs have good biocompatibility without obvious side effects. Thus, this work provides new insight into the development of NIR-II theranostics agents.

pH-Responsive Hyperbranched Polymer Nanoparticles to Combat Intracellular Infection by Disrupting Bacterial Wall and Regulating Macrophage Polarization.

Intracellular bacterial infections pose a serious threat to public health. Macrophages are a heterogeneous population of immune cells that play a vital role in intracellular bacterial infection. However, bacteria that survive inside macrophages could subvert the cell signaling and eventually reduce the antimicrobial activity of macrophages. Herein, dual pH-responsive polymer (poly[(3-phenylprop-2-ene-1,1-diyl)bis(oxy)bis(enthane-2,1-diyl)diacrylate-co-N-aminoethylpiperazine] (PCA)) nanoparticles were developed to clear intracellular bacteria by activating macrophages and destructing bacterial walls. The presence of acid-labile acetal linkages and tertiary amine groups in the polymer's backbone endow hyperbranched PCA dual pH-response activity that shows acid-induced positive charge increase and cinnamaldehyde release properties. The biodegraded PCA nanoparticles could significantly inhibit the growth of bacteria by damaging the bacterial walls. Meanwhile, PCA nanoparticles could uptake by macrophages, generate reactive oxygen species (ROS), and remodel the immune response by upregulating M1 polarization, leading to the reinforced antimicrobial capacity. Furthermore, PCA nanoparticles could promote bacteria-infected wound healing in vivo. Therefore, these dual pH-responsive PCA nanoparticles enabling bacteria-killing and macrophage activation provide a novel outlook for treating intracellular infection.

Mechanisms of Cynarine for treatment of non-alcoholic fatty liver disease based on the integration of network pharmacology, molecular docking and cell experiment.

BACKGROUND: Nonalcoholic Fatty Liver Disease (NAFLD) is a chronic Liver Disease prevalent all over the world. It has become more and more common in Japan, China and most western developed countries. The global prevalence rate is 25.24%, and the trend is increasing year by year. Related studies have shown that Cynarine has certain liver protection, lipid lowering and immune intervention effects. So, this study to systematically predict and analyze the mechanism of Cynarine in the treatment of non-alcoholic fatty liver disease (NAFLD) based on the integration of network pharmacology, molecular docking, and cell experiment. METHODS: We performed Heatmap and Venn diagram analyses to identify genes and targets in Cynarine treat NAFLD. The network of Cynarine-therapeutic targets and the protein-protein interaction network (PPI) was constructed. We used gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses to visualize associated functional pathways. The Sybyl tool was used to dock the Cynarine with key therapeutic targets molecularly. Finally, cell experiments were applied to validate the role of Cynarine in the treatment of NAFLD. RESULTS: The Cynarine could act on 48 targets of NAFLD, and the role of CASP3, TP53, MMP9, ELANE, NOTCH1 were more important. The PPI network showed that immune and inflammation-related targets played a pivotal role. The KEGG analysis found that the PI3K-Akt signaling pathway, cell cycle and MAPK signaling pathway may be the main pathways for Cynarine to prevent and treat NAFLD. Molecular docking studies confirmed that Cynarine has good binding activity with therapeutic targets. Cynarine reduced the fat deposition ability of NAFLD model cells, and effectively reduced the levels of ALT and AST released by liver cells due to excessive lipid accumulation. We also found that Cynarine inhibited the expression of AKT1 and MAPK1. CONCLUSIONS: This study revealed that Cynarine could significantly reduce the fat deposition ability of NAFLD model cells, which may be closely related to the effective regulation of AKT1 and MAPK1 expression by Cynarine.

Transcriptome analysis of mouse male germline stem cells reveals characteristics of mature spermatogonial stem cells.

Spermatogonial stem cells (SSCs) are adult stem cells in the testis of male animals and have the ability in self-renewal and differentiation. SSCs are derived from primordial germ cells (PGCs) that are mitotically arrested in the embryo before birth. Following the birth of the animal, PGCs resume mitosis and migrate from the centre of the seminiferous tubules to the basement membrane. The descendent of PGCs (also called gonocytes) establish stable SSC colonies in about a week postnatally in order to support the life-long spermatogenesis. Whether SSCs at different developmental stages differ in their molecular and cellular characteristics is currently unclear. In the presented study, we conducted bioinformatics analyses using transcriptomics data established previously in the laboratory on OCT4 (encoded by the pluripotent gene Pou5f1) expressing SSCs from the neonatal (3 days-post-partum, 3-dpp), juvenile (7-dpp) and adult (2~3-month) mice, including screen of differentially expressed genes (DEGs), protein-protein interaction (PPI) network analysis of DEGs and clustering of sub-networks from PPI. GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) analyses were also performed on clustered sub-networks of the PPI. In addition, all genes were analyzed using GSEA (gene set enrichment analysis) based on GO, KEGG and HALLMARK gene sets. The results showed that SSCs have a large number of DEGs among OCT4-positive SSCs from neonatal, juvenile and adult mice. The distinguishable biological functions encoded by these DEGs include biosynthesis and energy metabolism, immune response, cell junction and expression of migration and cell differentiation-related genes. Significant changes in the cell membrane composition of OCT4-positive SSCs may not only cause hypersensitive immune reactions but also affect the cell-cell contact and responses to secreted cytokines in the extracellular environment. The results also suggest that OCT4-positive SSCs may shift metabolic state from oxidative phosphorylation to glycolysis and significantly reduce the transcription of genes related to ribosome formation during aging. These results provide new clues for future research on the regulatory mechanisms of male germline stem cell development, growth and aging.

Phosphatidic acid directly binds with rice potassium channel OsAKT2 to inhibit its activity.

The plant Shaker K+ channel AtAKT2 has been identified as a weakly rectifying channel that can stabilize membrane potentials to promote photoassimilate phloem loading and translocation. Thus, studies on functional characterization and regulatory mechanisms of AtAKT2-like channels in crops are highly important for improving crop production. Here, we identified the rice OsAKT2 as the ortholog of Arabidopsis AtAKT2, which is primarily expressed in the shoot phloem and localized at the plasma membrane. Using an electrophysiological assay, we found that OsAKT2 operated as a weakly rectifying K+ channel, preventing H+ /sucrose-symport-induced membrane depolarization. Three critical amino acid residues (K193, N206, and S326) are essential to the phosphorylation-mediated gating change of OsAKT2, consistent with the roles of the corresponding sites in AtAKT2. Disruption of OsAKT2 results in delayed growth of rice seedlings under short-day conditions. Interestingly, the lipid second messenger phosphatidic acid (PA) inhibits OsAKT2-mediated currents (both instantaneous and time-dependent components). Lipid dot-blot assay and liposome-protein binding analysis revealed that PA directly bound with two adjacent arginine residues in the ANK domain of OsAKT2, which is essential to PA-mediated inhibition of OsAKT2. Electrophysiological and phenotypic analyses also showed the PA-mediated inhibition of AtAKT2 and the negative correlation between intrinsic PA level and Arabidopsis growth, suggesting that PA may inhibit AKT2 function to affect plant growth and development. Our results functionally characterize the Shaker K+ channel OsAKT2 and reveal a direct link between phospholipid signaling and plant K+ channel modulation.

Conjugated Polymers: Optical Toolbox for Bioimaging and Cancer Therapy.

Conjugated polymers (CPs) are capable of coordinating the electron coupling phenomenon to bestow powerful optoelectronic features. The light-harvesting and light-amplifying properties of CPs are extensively used in figuring out the biomedical issues with special emphasis on accurate diagnosis, effective treatment, and precise theranostics. This review summarizes the recent progress of CP materials in bioimaging, cancer therapeutics, and introduces the design strategies by rationally tuning the optical properties. The recent advances of CPs in bioimaging applications are first summarized and the challenges to clear the future directions of CPs in the respective area are discussed. In the following sections, the focus is on the burgeoning applications of CPs in phototherapy of the tumor, and illustrates the underlying photo-transforming mechanism for further molecular designing. Besides, the recent progress in the CPs-assistant drug therapy, mainly including drug delivery, gene therapeutic, the optical-activated reversion of tumor resistance, and synergistic therapy has also been discussed elaborately. In the end, the potential challenges and future developments of CPs on cancer diagnosis and therapy are also illuminated for the improvement of optical functionalization and the promotion of clinical translation.

Nanozyme-assisted technique for dual mode detection of organophosphorus pesticide.

A novel dual-mode analytical method by employing nanozyme was developed for the detection of organophosphorus pesticides (OPP) for the first time. The detection principle is that the pesticide could be hydrolyzed to para-nitrophenol (p-NP) in the presence of nanoceria as nanozyme. p-NP exhibits the bright yellow color, and its color intensity has a positive correlation with the pesticide concentration. Meanwhile, the characteristic absorption peak at 400 nm of p-NP increases gradually with the raised concentration of pesticide. Therefore, a dual-mode method including smartphone-based colorimetric and spectroscopic strategies was rationally developed. Herein, methyl-paraoxon was selected as the representative compound. Under the optimum conditions, the detection limits of both two strategies were calculated to be 0.42 µmol L-1. Finally, the present method was successfully applied in three edible medicinal plants (Semen nelumbinis, Semen Armeniacae Amarum, Rhizoma Dioscoreae). The present work offers a reliable and convenient approach for routine detection of pesticide based on two different detection mechanisms.

Ginsenoside Rg5 attenuates hepatic glucagon response via suppression of succinate-associated HIF-1α induction in HFD-fed mice.

AIMS/HYPOTHESIS: Ginsenosides regulate glucose homeostasis. This study investigated the effect of ginsenoside Rg5 (Rg5) on the hepatic glucagon response, focusing on the regulation of metabolism. METHODS: Mice fed a high-fat diet (HFD) showed increased hepatic glucose production (HGP). We observed the effects of Rg5 on hepatic fatty acid oxidation and glucagon response. The regulation of phosphodiesterase (PDE) 4B by succinate was also investigated in hepatocytes. RESULTS: Rg5 inhibited endogenous glucose production in HFD-fed mice. Rg5 reduced cyclic AMP (cAMP) accumulation and inhibited transcriptional regulation of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) by dephosphorylation of the cAMP response element-binding transcription factor in the liver, demonstrating the inhibitory effect on hepatic glucagon response. HFD feeding increased succinate accumulation in the liver due to the reversal of succinate dehydrogenase activation and triggered hypoxia-inducible factor-1α (HIF-1α) induction. Succinate prevented cAMP degradation by inactivating PDE4B, thereby increasing cAMP accumulation in response to glucagon. Knockdown of HIF-1α with small interfering RNA diminished the effect of succinate, indicating that HIF-1α was essential for succinate to inactivate PDE4B. Rg5 inhibited succinate accumulation in hepatocytes by combating fatty acid oxidation, and thus reduced cAMP accumulation by blocking succinate/HIF-1α induction. Rg5 reduced HGP as a consequence of the inhibition of the glucagon response. CONCLUSIONS/INTERPRETATION: Succinate acted as a metabolic signal to enhance the hepatic glucagon response. Rg5 reduced hepatic succinate accumulation by combating fatty acid oxidation and attenuated the hepatic glucagon response by suppressing succinate/HIF-1α induction, suggesting that succinate-associated HIF-1α induction in hepatocytes might be a therapeutic target in the treatment of diabetes.

Differential regulation of baicalin and scutellarin on AMPK and Akt in promoting adipose cell glucose disposal.

Baicalin and scutellarin, two flavonoid glucuronic acids isolated from Scutellaria baicalensis, exhibit beneficial effects on glucose homeostasis. Baicalin and scutellarin are similar in structure except scutellarin has an additional hydroxyl at composition C-4'. In this work, we observed that baicalin and scutellarin promoted glucose disposal in mice and in adipocytes. Baicalin selectively increased phosphorylation of AMP-activated kinase (AMPK), while scutellarin selectively enhanced Akt phosphorylation. Both of them increased AS160 phosphorylation and glucose uptake in basal condition. AMPK inhibitor or knockdown of AMPK by siRNA blocked baicalin-induced AS160 phosphorylation and glucose uptake, but showed no effects on scutellarin. In contrast, Akt inhibitor and knockdown of Akt with siRNA decreased scutellarin-stimulated glucose uptake but had no effects on baicalin. The molecular dynamic simulations analysis showed that the binding energy of baicalin to AMPK (-34.30kcal/mol) was more favorable than scutellarin (-21.27kcal/mol), while the binding energy of scutellarin (-29.81kcal/mol) to Akt was much more favorable than baicalin (4.04kcal/mol). Interestingly, a combined treatment with baicalin and scutellarin acted synergistically to enhance glucose uptake in adipocytes (combination index: 0.94-0.046). In conclusion, baicalin and scutellarin, though structurally similar, promoted glucose disposal in adipocytes by differential regulation on AMPK and Akt activity. Our data provide insight that multicomponent herbal medicines may act synergistically on multiple targets.

Unequal distribution of 16S mtrRNA at the 2-cell stage regulates cell lineage allocations in mouse embryos.

Cell lineage determination during early embryogenesis has profound effects on adult animal development. Pre-patterning of embryos, such as that of Drosophila and Caenorhabditis elegans, is driven by asymmetrically localized maternal or zygotic factors, including mRNA species and RNA binding proteins. However, it is not clear how mammalian early embryogenesis is regulated and what the early cell fate determinants are. Here we show that, in mouse, mitochondrial ribosomal RNAs (mtrRNAs) are differentially distributed between 2-cell sister blastomeres. This distribution pattern is not related to the overall quantity or activity of mitochondria which appears equal between 2-cell sister blastomeres. Like in lower species, 16S mtrRNA is found to localize in the cytoplasm outside of mitochondria in mouse 2-cell embryos. Alterations of 16S mtrRNA levels in one of the 2-cell sister blastomere via microinjection of either sense or anti-sense RNAs drive its progeny into different cell lineages in blastocyst. These results indicate that mtrRNAs are differentially distributed among embryonic cells at the beginning of embryogenesis in mouse and they are functionally involved in the regulation of cell lineage allocations in blastocyst, suggesting an underlying molecular mechanism that regulates pre-implantation embryogenesis in mouse.

Comparative Gut Microbiomes of Four Species Representing the Higher and the Lower Termites.

Aiming at learning the association between the gut microbiota and termites with different diet habits and phylogenetic positions, the gut bacteria of three populations for each of the two higher termites (wood-feeding Mironasutitermes shangchengensis and fungus-feeding Odontotermes formosanus) and two wood-feeding lower termites (Tsaitermes ampliceps and Reticulitermes flaviceps) were analyzed by high-throughput 454 pyrosequencing of 16S V1-V3 amplicons. As results, 132 bacterial genera and some unidentified operational taxonomic units within 29 phyla in the gut bacteria were detected, with Spirochaetes (11-55%), Firmicutes (7-18%), Bacteroidetes (7-31%), and Proteobacteria (8-14%) as the main phyla, and Treponema, TG5, Dysgonomonas, Tannerella, za29, Lactococcus, Pseudomonas, and SJA-88 as the common genera in all the four termites. The diversity of gut bacterial communities in the higher termite guts was significantly greater than that in the lower termites; while the gut microbiota in M. shangchengensis (wood-feeding higher termite) was more similar to those of the wood-feeding lower termites rather than that of O. formosanus (fungus-feeding higher termite), and phylum Spirochaetes and nitrogen-fixing bacteria were super-dominant in the wood-feeding termites, despite of their phylogenetic relations. This study reported for the first time the gut bacterial communities for the termites of M. shangchengensis and T. ampliceps and the comparative analyses showed that the gut microbial communities varied according to the phylogeny and the diet habits of termites.