MicroRNAs (miRNAs) are small, single stranded, non-coding RNA molecules, about 19–25 nucleotides in length, which regulate the development and functions of reproductive system of mammal. To discover novel miRNAs and identify the differential expression of them in ovine ovary and testis tissues, the study constructed two libraries by using next-generation sequencing technologies (Solexa high-throughput sequencing technique). As a result, 9 321 775 and 9 511 538 clean reads were obtained from the ovary and testis separately, which included 130 562 (90 genes of ovary) and 56 272 (85 genes of testis) of known miRNAs and 486 potential novel miRNAs reads. In this study, a total of 65 conserved miRNAs were significantly differentially expressed (P<0.01) between the two samples. Among them, 28 miRNAs were up-regulated and 3 miRNAs were down-regulated on ovary compared with testis. In addition, the known miRNAs with the highest expression level (5 miRNAs) and 30 novel miRNAs with the functions related to reproduction were validated using the real-time quantitative RT-PCR. Moreover, the gene ontology (GO) annotation and Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis showed that differentially expressed miRNAs were involved in ovary and testis physiology, including signal transduction, gonad development, sex differentiation, gematogenesis, fertilization and embryo development. The results will be helpful to facilitate studies on the regulation of miRNAs during ruminant reproduction.

Somatic hybridization is performed to obtain significant cytoplasmic male sterility (CMS) lines, whose CMS genes are derived either from the transfer of sterile genes from the mitochondrial genome of donor parent to the counterpart of receptor or production of new sterile genes caused by mitochondrial genome recombination of the biparent during protoplast fusion. In this study, a novel male sterile line, SaNa-1A, was obtained from the somatic hybridization between Brassica napus and Sinapis alba. The normal anther development of the maintainer line, SaNa-1B, and the abortive process of SaNa-1A were described through phenotypic observations and microtome sections. The floral organ of the sterile line SaNa-1A was sterile with a shortened filament and deflated anther. No detectable pollen grains were found on the surface of the sterile anthers. Semi-thin sections indicated that SaNa-1A aborted in the pollen mother cell (PMC) stage when vacuolization of the tapetum and PMCs began. The tapetum radically elongated and became highly vacuolated, occupying the entire locule together with the vacuolated microspores. Therefore, SaNa-1A is different from other CMS lines, such as ogu CMS, pol CMS and nap CMS as shown by the abortive process of the anther.

Mitochondrial malate dehydrogenase (mMDH) and citrate synthase (CS) are sequential enzymes in Krebs cycle. mMDH, CS and the complex between mMDH and CS (mMDH+CS) were treated with nitric oxide solution. The roles of notric oxide (NO) on the secondary structures and the interactions between mMDH and CS were studied using circular diehroism (CD) and Fourier transform surface plasmon resonance (FT-SPR), respectivley. The effects of NO on the activities of mMDH, CS and mMDH+CS were also studied. And the regulations by NO on mMDH and CS were simulated by PyMOL software. The results of SPR confirmed that strong interaction between mMDH and CS existed and NO could significantly regulate the interaction between the two enzymes. NO reduced the mass percents of α-helix and increased that of random in mMDH, CS and mMDH+CS. NO increased the activities of CS and mMDH+CS, and inhibited the activity of mMDH. Graphic simulation indicated that covalent bond was formed between NO and Asn242 in active site of CS. However, there was no direct bond between NO and mMDH. The increase in activity of mMDH+CS complex depended mostly on the interaction between NO and CS. All the results suggested that the regulations by NO on the activity and interaction between mMDH and CS were accord with the changes in mMDH, CS and mMDH+CS caused by NO.