Synthesis of 3D flower-like ZnO/ZnCo2O4 composites with the heterogeneous interface for excellent electromagnetic wave absorption properties.

Reasonable structure and composition are essential for electromagnetic wave absorption (EMW). Herein, ZnO hollow spheres were prepared with carbon spheres as templates and then synthesized ZnO/ZnCo2O4 composites by the solvothermal method and annealing treatment. The flower-like ZnCo2O4 material was produced by self-assembly of ZnCo2O4 nanosheets. The absorbing material with the complex structure has multiple scattering and reflection, conduction loss, resonance, and eddy current loss characteristics. Furthermore, the addition of ZnO hollow spheres has a significant impact on electromagnetic parameters and absorption properties. As a result, the addition of ZnO hollow spheres can greatly enhance the complex permittivity of the ZnO/ZnCo2O4 composites and obtain excellent EMW absorbing properties. It is worth noting that ZnO/ZnCo2O4 composites show the best EMW absorption properties when the ZnO hollow spheres were added up to 5 mg. The minimum reflection loss is -55.42 dB and a matching thickness of 1.99 mm while the maximum effective absorption bandwidth can also reach 7.44 GHz with a matching thickness of 2.4 mm. Our research can prove that the structure and composition have a significant influence on the properties of the absorbing material, which provides ideas for the development of absorbing materials with high-performance.

Overexpression of lncRNA NEAT1 mitigates multidrug resistance by inhibiting ABCG2 in leukemia.

Leukemia is a heterogeneous clonal disorder in which early hematopoietic cells fail to differentiate and do not undergo programmed cell death or apoptosis. Less than one-third of adult patients with leukemia are managed using current therapies due to the emergence of multidrug resistance (MDR), emphasizing the need for newer and more robust approaches. Recent reports have suggested that long non-coding RNAs (lncRNAs) contribute to selective gene expression and, hence, could be manipulated effectively to halt the progression of cancer. However, little is known regarding the role of lncRNA in leukemia. Nuclear paraspeckle assembly transcript 1 (NEAT1) is a nuclear-restricted lncRNA involved in the pathogenesis of certain types of cancer. Deregulated expression of NEAT1 has been reported in a number of human malignancies, including leukemia and other solid tumors. The present study aimed to characterize the role of NEAT1 in the regulation of MDR in leukemia. Using reverse transcription-quantitative polymerase chain reaction, it was demonstrated that NEAT1 messenger RNA (mRNA) expression levels were significantly downregulated in leukemia patient samples compared with those from healthy donors. Furthermore, NEAT1 mRNA expression was repressed in a number of leukemia cell lines, including K562, THP-1, HL-60 and Jurkat cells, compared with peripheral white blood control cells, consistent with the expression observed in patients with leukemia. In addition, the transfection of a NEAT1 overexpression plasmid into K562 and THP-1 leukemia cell lines alleviated MDR induced by cytotoxic agents, such as Alisertib and Bortezomib, through inhibition of ATP-binding cassette G2. Although more robust studies are warranted, the current findings provide the basis for the use of NEAT1 as a novel promising target in the treatment of leukemia.

Long Noncoding RNA MHRT Protects Cardiomyocytes against H2O2-Induced Apoptosis.

Acute myocardial infarction (AMI) remains a leading cause of morbidity and mortality worldwide. The exploration of new biomarkers with high sensitivity and specificity for early diagnosis of AMI therefore becomes one of the primary task. In the current study, we aim to detect whether there is any heart specific long noncoding RNA (lncRNA) releasing into the circulation during AMI, and explore its function in the neonatal rat cardiac myocytes injury induced by H2O2. Our results revealed that the cardiac-specific lncRNA MHRT (Myosin Heavy Chain Associated RNA Transcripts) was significantly elevated in the blood from AMI patients compared with the healthy control ((*) p<0.05). Using an in vitro neonatal rat cardiac myocytes injury model, we demonstrated that lncRNA MHRT was upregulated in the cardiac myocytes after treatment with hydrogen peroxide (H2O2) via real-time RT-PCR (qRT-PCR). Furthermore, we knockdowned the MHRT gene by siRNA to confirm its roles in the H2O2-induced cardiac cell apoptosis, and found that knockdown of MHRT led to significant more apoptotic cells than the non-target control ((**) p<0.01), indicating that the lncRNA MHRT is a protective factor for cardiomyocyte and the plasma concentration of MHRT may serve as a biomarker for myocardial infarction diagnosis in humans AMI.

Horizontal gene transfer in plants.

Horizontal gene transfer (HGT) describes the transmission of genetic material across species boundaries. HGT often occurs in microbic and eukaryotic genomes. However, the pathways by which HGTs occur in multicellular eukaryotes, especially in plants, are not well understood. We systematically summarized more than ten possible pathways for HGT. The intimate contact which frequently occurs in parasitism, symbiosis, pathogen, epiphyte, entophyte, and grafting interactions could promote HGTs between two species. Besides these direct transfer methods, genes can be exchanged with a vector as a bridge: possible vectors include pollen, fungi, bacteria, viruses, viroids, plasmids, transposons, and insects. HGT, especially when involving horizontal transfer of transposable elements, is recognized as a significant force propelling genomic variation and biological innovation, playing an important functional and evolutionary role in both eukaryotic and prokaryotic genomes. We proposed possible mechanisms by which HGTs can occur, which is useful in understanding the genetic information exchange among distant species or distant cellular components.

Revisiting an important component of plant genomes: microsatellites.

Microsatellites are some of the most highly variable repetitive DNA tracts in genomes. Few studies focus on whether the characteristic instability of microsatellites is linked to phenotypic effects in plants. We summarise recent data to investigate how microsatellite variations affect gene expression and hence phenotype. We discuss how the basic characteristics of microsatellites may contribute to phenotypic effects. In summary, microsatellites in plants are universal and highly mutable, they coexist and coevolve with transposable elements, and are under selective pressure. The number of motif nucleotides, the type of motif and transposon activity all contribute to the nonrandom generation and decay of microsatellites, and to conservation and distribution biases. Although microsatellites are generated by accident, they mature through responses to environmental change before final decay. This process is mediated by organism adjustment mechanisms, which maintain a balance between birth versus death and growth versus decay in microsatellites. Close relationships also exist between the physical structure, variation and functionality of microsatellites: in most plant species, sequences containing microsatellites are associated with catalytic activity and binding functions, are expressed in the membrane and organelles, and participate in the developmental and metabolic processes. Microsatellites contribute to genome structure and functional plasticity, and may be considered to promote species evolution in plants in response to environmental changes. In conclusion, the generation, loss, functionality and evolution of microsatellites can be related to plant gene expression and functional alterations. The effect of microsatellites on phenotypic variation may be as significant in plants as it is in animals.

Characterization and evolution of 5' and 3' untranslated regions in eukaryotes.

Untranslated regions (UTRs) in eukaryotes play a significant role in the regulation of translation and mRNA half-life, as well as interacting with specific RNA-binding proteins. However, UTRs receive less attention than more crucial elements such as genes, and the basic structural and evolutionary characteristics of UTRs of different species, and the relationship between these UTRs and the genome size and species gene number is not well understood. To address these questions, we performed a comparative analysis of 5' and 3' untranslated regions of different species by analyzing the basic characteristics of 244,976 UTRs from three eukaryote kingdoms (Plantae, Fungi, and Protista). The results showed that the UTR lengths and SSR frequencies in UTRs increased significantly with increasing species gene number while the length and G+C content in 5' UTRs and different types of repetitive sequences in 3' UTRs increased with the increase of genome size. We also found that the sequence length of 5' UTRs was significantly positively correlated with the presence of transposons and SSRs while the sequence length of 3' UTRs was significantly positively correlated with the presence of tandem repeat sequences. These results suggested that evolution of species complexity from lower organisms to higher organisms is accompanied by an increase in the regulatory complexity of UTRs, mediated by increasing UTR length, increasing G+C content of 5' UTRs, and insertion and expansion of repetitive sequences.

Characterization and functional annotation of nested transposable elements in eukaryotic genomes.

The movement of transposable elements (TE) in eukaryotic genomes can often result in the occurrence of nested TEs (the insertion of TEs into pre-existing TEs). We performed a general TE assessment using available databases to detect nested TEs and analyze their characteristics and putative functions in eukaryote genomes. A total of 802 TEs were found to be inserted into 690 host TEs from a total number of 11,329 TEs. We reveal that repetitive sequences are associated with an increased occurrence of nested TEs and sequence biased of TE insertion. A high proportion of the genes which were associated with nested TEs are predicted to localize to organelles and participate in nucleic acid and protein binding. Many of these function in metabolic processes, and encode important enzymes for transposition and integration. Therefore, nested TEs in eukaryotic genomes may negatively influence genome expansion, and enrich the diversity of gene expression or regulation.

Characterization of transcriptional activation and inserted-into-gene preference of various transposable elements in the Brassica species.

Transposable elements (TEs) have attracted increasing attention because of their tremendous contributions to genome reorganization and gene variation through dramatic proliferation and excision via transposition. However, less known are the transcriptional activation of various TEs and the characteristics of TE insertion into genomes at the genome-wide level. In the present study, we focused on TE genes for transposition and gene disruption by insertion of TEs in expression sequences of Brassica, to investigate the transcriptional activation of TEs, the biased insertion of TEs into genes, and their salient characteristics. Long terminal repeat (LTR-retrotransposon) accounted for the majority of these active TE genes (70.8%), suggesting that transposition activation varied with TE type. 6.1% genes were interrupted by LTR-retrotransposons, which indicated their preference for insertion into genes. TEs were preferentially inserted into cellular component-specific genes acted as "binding" elements and involved in metabolic processes. TEs have a biased insertion into some host genes that were involved with important molecular functions and TE genes exhibited spatiotemporal expression. These results suggested that various types of transposons differentially contributed to gene variation and affected gene function.

Large-scale development of functional markers in Brassica species.

Numerous quantitative trait loci (QTL) have been detected in Brassica species, but fine-mapping of major QTL has advanced slowly. The development of functional markers can overcome this barrier. We used publicly available PlantGDB-assembled unique transcripts (PUTs) from Brassica species to design 7836 functional simple sequence repeat (SSR) primer pairs. Functional annotation of the PUTs containing SSRs was done by Blast2GO. The PUTs harbouring SSRs were mainly involved with nucleotide or protein binding and enzyme activity, and preferentially functioned in membranes and cytoplasm. Totally, 210 PUT primer pairs were selected to test their polymorphism, stability, and PCR quality. Approximately 70% (147) of the primer pairs resulted in successful amplification with an average polymorphic information content (PIC) value of 0.49. The highest level of polymorphism was dinucleotide repeat SSRs, followed by tri- and mononucleotide repeats. Approximately 60% of the primer pairs showed good transferability among Brassica species. These results show that the development of markers from PUTs is a feasible and simple approach to develop functional SSR markers on a large scale across Brassica species. In addition, these markers can provide a novel alternative that is a putative approach for rapid determination of candidate genes, genetic mapping, genetic diversity analysis, and comparative mapping in Brassica species.

Characterization and comparison of gene-based simple sequence repeats across Brassica species.

Simple sequence repeats (SSRs) are important components of eukaryotic genomes and may play an important role in regulating gene expression. However, the characteristics of genic SSRs and the effect of interspecific hybridization and polyploidization on genic SSRs seem not to have received desired attention in terms of scientific investigations. To determine the features of genic SSRs and elucidate their role in polyploidization process of the Brassica family, we identified SSRs in Plant Genome Database-assembled unique transcripts (PUTs) of Brassica species. A higher density of SSRs and a greater number of compound motif SSRs and mononucleotide motif types with large average number of repeats were detected in allotetraploid Brassica napus than in the diploid parental species (Brassica rapa and Brassica oleracea). In addition, a greater proportion of SSR-PUTs were found to be associated with the stress response and developmental processes in B. napus than in the parents. A negative correlation between the repeat number and the motif type and the total length, and a positive correlation between the repeat number and the total length of SSRs were observed. PUT-SSR might be generated from A/T-rich regions. The successful development of 123 pairs of SSR primers for Brassica PUTs showed that SSR-PUTs could be exploited as gene-based SSR functional markers for application in Brassica breeding. These results indicate that interspecific hybridization and polyploidization could trigger the amplification of SSRs, and long SSRs might become shorter to enable the plant to adapt to environmental and artificial selection.