The pentatricopeptide repeat protein EMP601 functions in maize seed development by affecting RNA editing of mitochondrial transcript ccmC

Although several pentatricopeptide repeat(PPR) proteins are involved in post-transcriptional processing of mitochondrial RNA, it is unclear which specific protein is involved in the RNA editing of ccmC in maize(Zea mays). Here we report the identification of the maize empty pericarp 601(emp601) mutant and the map-based cloning of the Emp601 gene, which encodes an E2-type PPR protein that is targeted to mitochondria. A single-nucleotide deletion in the emp601 mutant caused a frameshift and introduced a premature stop codon into the predicted EMP601. This mutation was associated with reduced accumulation of mitochondrial complex Ⅲ as well as with inhibition of growth and differentiation of basal endosperm transfer layer cells, leading to final degeneration of the embryo and endosperm. We determine that loss of EMP601 function prevents the C-to-U RNA editing of the mitochondrial transcript ccmC at position 358.EMP601 binds to the ccmC transcript and directly interacts with Multiple organellar RNA editing factor 8and may be a component of the plant mitochondrial editosome. We conclude that EMP601 functions in RNA editing of mitochondrial ccmC transcripts and influences mitochondrial function and seed development.

Olive oil ameliorate allergic response in ovalbumin-induced food allergy mouse by promoting intestinal mucosal immunity

The numerous health benefits of olive oil are widely known,however,it also provides anti-allergic properties that have not yet been fully defined.In this study,the anti-allergic activity of olive oil was evaluated by analyzing the clinical symptoms and immune-related factors in BALB/c mice that had ingested600 mg/(kg·day)olive oil for two weeks prior to the evaluation.An allergy model was subsequently constructed for analysis,the results of which showed that the olive oil reduced the scores of allergic symptoms in the mice,and up-regulated the hypothermia and the decline in the immune organ index.Moreover,fewer allergy-related cytokines and reduced intestinal inflammation was discovered in the olive oil-treated group.In addition,analysis of intestinal mucosal immune-related factors revealed that the olive oil promoted the expression of intestinal tight junction proteins(Claudin-1,Occludin,and ZO-1)and IL-22,and helped maintain the integrity of the intestinal epithelial physical barrier.Increased levels of mucin 2 andβ-defensin were also found in the intestinal mucus of the olive oil-treated mice.These findings suggest that the oral administration of olive oil effectively attenuated the ovalbumin-induced allergic immune response in the mice,and had a positive effect on intestinal epithelial mucosal immunity.

Maize MS2 encodes an ATP-binding cassette transporter that is essential for anther development

The anther cuticle and pollen exine play a critical role in male gametophyte development. The sporopollenin precursors and cuticular lipid monomers are transported to the surface of the microspores and the epidermis by lipid transport proteins(LTPs) and ATP-binding cassette G(ABCG) transporters for the formation of the pollen wall and anther cuticle, respectively. However, the function of ABCG transporters in maize anther development is unclear. Here, we cloned the MS2 gene from the maize male sterile2 mutant using map-based cloning and determined that it encodes an ABCG transporter. MS2 protein was experimentally confirmed to be located on the cell membrane. The quantitative real-time PCR(qRT-PCR)results showed that MS2 was ubiquitously expressed in all vegetative and reproductive tissues, whereas a high transcriptional level of MS2 was observed in anthers, especially at the young microspore stage. Gas chromatography-mass spectrometry(GC–MS) analysis showed decreased accumulation of cutin and wax components in ms2 anthers, indicating that MS2 plays a role in the transport of lipid molecules to anther cuticle and pollen exine. To our knowledge, MS2 is the first reported ABCG transporter gene that participates in anther development in maize.

Photodynamic Therapy Activities of 10-（4-Formylphenyl）-5,15-bis（pentafluorophenyl）corrole and Its Gallium Complex

10-（4-Formylphenyl）-5,15-bis（pentafluorophenyl）corrole 1 and its gallium complex 1-Ga were used to investigate their photocytotoxicity in liver cancer （BEL-7402）, lung cancer （A549） and cervical cancer （Siha, Hela） cell lines. Among all the tested tumor cells, Siha tumor cells were the most sensitive to photodynamic therapy （PDT） treatment by 1 and 1-Ga. PDT IC50 of 1 and 1-Ga toward Siha tumor cell reaches 1.3 and 0.8 gmol/L respectively, which is 10-fold higher than that of cisplatin. 1 and 1-Ga might pass across the tumor cell membrane smoothly without the help of carrier protein, and mainly localized in the cytoplasm of tumor cell. After PDT treatment, the intracellular reactive oxygen species （ROS） level increased and the mitochondrial membrane potential decreased significantly, which would finally result in the apoptosis of tumor cells.

Polyhydric Corrole and Its Gallium Complex： Synthesis, DNA-binding Properties and Photodynamic Activities

A new hydrophilic polyhydric corrole （1） and its Ga（III） complex （1-Ga） were synthesized and characterized. Corroles 1 and 1-Ga bind to calf thymus DNA externally and exhibit remarkable photonuclease-like activity. Singlet oxygen （102） was identified as the reactive oxygen species involved. These corroles also exhibit significant photocytotoxicity against HeLa, A549, BEL-7402 and HepG2 tumor cell lines. They mainly accumulated in the nuclei of tumor cells. ROS-mediated mitochondrial damage and intracellular DNA disintegration contributed to the observed photodynamic activity.

QTG-Seq Accelerates QTL Fine Mapping through QTL Partitioning and Whole-Genome Sequencing of Bulked Segregant Samples

Deciphering the genetic mechanisms underlying agronomic traits is of great importance for crop improvement. Most of these traits are controlled by multiple quantitative trait loci (QTLs), and identifying the underlying genes by conventional QTL fine-mapping is time-consuming and labor-intensive. Here, we devised a new method, named quantitative trait gene sequencing (QTG-seq), to accelerate QTL fine-mapping. QTGseq combines QTL partitioning to convert a quantitative trait into a near-qualitative trait, sequencing of bulked segregant pools from a large segregating population, and the use of a robust new algorithm for identifying candidate genes. Using QTG-seq, we fine-mapped a plant-height QTL in maize (Zea mays L.), qPH7, to a 300-kb genomic interval and verified that a gene encoding an NF-YC transcription factor was the functional gene. Functional analysis suggested that qPH7-encoding protein might influence plant height by interacting with a CO-like protein and an AP2 domain-containing protein. Selection footprint ana卜 ysis indicated that qPH7 was subject to strong selection during maize improvement. In summary, QTG-seq provides an efficient method for QTL fine-mapping in the era of “big data".

Combined use of phospholipid complexes and self-emulsifying microemulsions for improving the oral absorption of a BCS class IV compound, baicalin

The aim of this study was to develop a formulation to improve the oral absorption of baicalin(BA)by combining a phospholipid complex(PC)and self-emulsifying microemulsion drug delivery system(SMEDDS),termed BA–PC–SMEDDS.BA–PC was prepared by a solvent evaporation method and evaluated by complexation percentage(CP).The physicochemical properties of BA–PC were determined.The synergistic effect of PC and SMEDDS on permeation of BA was studied in vitro with Caco-2 cells and in situ with a single pass intestinal perfusion model.The improved bioavailability of BA in BA–PC–SMEDDS was confirmed in an in vivo rat model.The CP of BA–PC reached 100%when the molar ratio of drug to phospholipid(PP)was Z1:1.The solubility of BA–PC increased in both water and octanol,and the log P o/w of BA–PC was increased significantly.BA–PC–SMEDDS could be dispersed more evenly in water,compared to BA and BA–PC.Both the Caco-2 cell uptake and single-pass intestinal perfusion models illustrated that transport of BA in BA–PC was lower than that of free BA,while improved significantly in BA–PC–SMEDDS.The relative bioavailability of BA–PC(1:2)–SMEDDS was 220.37%.The combination system of PC and SMEDDS had a synergistic effect on improving the oral absorption of BA.

The U6 Biogenesis-Like I Plays an Important Role in Maize Kernel and Seedling Development by Affecting the 3＇ End Processing of U6 snRNA

Regulation of gene expression at the post-transcriptional level is of crucial importance in the development of an organism. Here we present the characterization of a maize gene, U6 biogenesis-like 1 （UBL1）, which plays an important role in kernel and seedling development by influencing pre-mRNA splicing. The ubll mutant, exhibiting small kernel and weak seedling, was isolated from a Mutator-tagged population. Trans- genic complementation and three independent mutant alleles confirmed that UBL1, which encodes a putative RNA exonuclease belonging to the 2H phosphodiesterase superfamily, is responsible for the phenotype of ubll. We demonstrated that UBL1 possess the RNA exonuclease activity in vitro and found that loss of UBL1 function in ubll causes decreased level and abnormal 3＇ end constitution of snRNA U6, resulting in splicing defect of mRNAs. Through the in vitro and in vivo studies replacing two histidines with alanines in the H-X-T/S-X （X is a hydrophobic residue） motifs we demonstrated that these two motifs are essential for the normal function of UBL1. We further showed that the function of UBL1 may be conserved across a wide phylogenetic distance as the heterologous expression of maize UBL1 could complement the Arabidopsis ubll mutant.