The seminiferous growth factor induces proliferation of TM4 cells in serum-free medium

The seminiferous growth factor (SGF) of the mammalian testes induces DNA synthesis and cell proliferation of Balb/c 3T3 cells (Bellvé and Feig, 1984; Rec Prog Hormone Res 40:531-567). In this study, SGF was purified 80,000- to 100,000-fold from calf testes and used to examine the growth of TM4 cells in a chemically defined medium. Cells were seeded sparsely in Dulbecco's Modified Eagles/Ham's F12 medium (1:1;v:v) (DME/F12 degrees), containing epidermal growth factor (EGF; 1 ng/ml), insulin (1; 10 micrograms/ml), and transferrin (Tr; 5 micrograms/ml) (DME/F12). After 24 h, the medium was replaced with DME/F12 degrees supplemented with SGF, EGF, 1, or Tr, in two-, three- or four-way combinations. Cell numbers were quantified after another 48 h of culture. EGF, I, and Tr, alone or in two-way combinations, were not mitogenic for TM4 cells. By contrast, SGF (1 U) alone, or with any two of these factors, stimulated TM4 cell proliferation to commensurate levels, and to twofold greater numbers than occurred with the combination of EGF, I, and Tr. Synergisms or inhibitions were not measurable. Follicle-stimulating hormone, luteinizing hormone, prolactin, acidic fibroblast growth factor, or basic fibroblast growth factor was weakly or not mitogenic for TM4 cells. The effect of SGF on cell proliferation was inhibited by 1 microM - 1 nM retinoic acid, but not by retinol or retinyl acetate. SGF was mitogenic for bovine adrenal capillary endothelial cells, an effect that was potentiated by 10 micrograms heparin/ml. Thus, SGF can induce proliferation of TM4 cells and capillary endothelial cells. The former provides a sensitive, and selective, serum-free, bioassay system for SGF activity.     

MicroRNAs transcriptionally regulate promoter activity in Arabidopsis thaliana

Micro RNAs(mi RNAs) are vital regulators that repress gene expression in the cytoplasm in two main ways: m RNA degradation and translational inhibition. Several animal studies have shown that mi RNAs also target promoters, thereby activating expression.Whether this mi RNA action also occurs in plants is unknown. In this study, we demonstrated that several mi RNAs regulate target promoters in Arabidopsis thaliana. For example, mi R5658 was predominantly present in the nucleus and activated the expression of AT3 G25290 directly by binding to its promoter. Our observations suggest that this mode of action may be a general feature of plant mi RNAs, and thus provide insight into the vital roles of plant mi RNAs in the nucleus.     

2′-MeO-RNA Containing Oligodeoxyribonucleotide Primers Can Prevent Template-independent Base Extension on Microarrays

DNA microarrays require tens of thousands of deoxyoligonucleotides to be registered in an addressable fashion through immobilization, so that they have the high-throughput capability of analyzing a large number of samples simultaneously in a minimal volume of each reagent. However, using immobilized DNA molecules on microarrays can impose certain technical problems for some assays. For example, high background noise has been observed in using immobilized oligonucleotide microarrays (DNA chip) for primer extension reactions. This noise may be associated with the reactions of secondary structures formed by the adjacent primers physically constrained on the surface. Single-base extension (SBE) of arrayed primers on a chip has been extensively used in mini-sequencing to examine single nucleotide polymorphisms (SNP). Some primers appeared to be extendable in the absence of any template and thus competed against the base extension directed by the assay target such as genomic DNA. In this article, a method is reported that is capable of reducing template-independent extension by the substitution of a 2′-methoxyribonucleotide in the otherwise oligodeoxyribonucleotide primer. The surrogate compound placed at the 5′-end of the putative secondary structure sequence of a given primer was able to inhibit template-independent extension and to improve data quality of surface-attached primer extension assays.     

Statures in Han populations of China

<正>Dear Editor,Shortly after initiating the"Physical Anthropological Research on Han Chinese"research project,we applied uniform sampling methods as well as methods and instruments of measurement to obtain a complete set of measurements of physical anthropological indicators among Han populations across China.Among these measurements,body stature was a key indicator.Currently,there should be reliable     

Effects of warming and nutrient fluctuation on invader Chromolaena odorata and natives in artificial communities

Plant Ecology - There is increasing evidence that climate change and nutrient fluctuations can affect the invasion of alien plants. However, most studies have been performed in pairwise experiments...     

Inhibition of tumor propellant glutathione peroxidase 4 induces ferroptosis in cancer cells and enhances anticancer effect of cisplatin

Glutathione peroxidase 4 (GPX4) has been confirmed to inhibit ferroptosis in cancer cells, however, whether GPX4 serves as an oncogene is not clear. In this study, the expression of GPX4 and its influence to survival of patients with cancer were analyzed via public databases. Furthermore, the epigenetic regulation of GPX4 and the relation between GPX4 and chemoresistance of different anticancer drugs was also detected. Most importantly, cytological assays were performed to investigate the function of GPX4 in cancer cells. The results showed that GPX4 was higher expressed in cancer tissues than normal and was negatively associated with prognosis of patients. Furthermore, at upstream of GPX4 there was low DNA methylation sites and enhanced level of H3K4me3 and H3K27ac, indicating that high level of GPX4 in cancer may resulted from epigenetic regulation. Moreover, GPX4 was positively related to chemoresistance of anticancer drugs L-685458, lapatinib, palbociclib, and topotecan. In addition, GPX4 may potentially be involved in translation of protein, mitochondrial respiratory chain complex I assembly, electron transport oxidative phosphorylation, nonalcoholic fatty liver disease, and metabolic pathways. Finally, we detected that GPX4 inhibited ferroptosis in cancer cells, the inhibition of GPX4 via RSL3 could enhance the anticancer effect of cisplatin in vitro and in vivo. In conclusion, GPX4 acts as an oncogene and inhibits ferroptosis in cancer cells, the anticancer effect of cisplatin can be enhanced by GPX4 inhibition.     

Diverse phylogeny and morphology of magnetite biomineralized by magnetotactic cocci

Magnetotactic bacteria (MTB) are diverse prokaryotes that produce magnetic nanocrystals within intracellular membranes (magnetosomes). Here, we present a large-scale analysis of diversity and magnetosome biomineralization in modern magnetotactic cocci, which are the most abundant MTB morphotypes in nature. Nineteen novel magnetotactic cocci species are identified phylogenetically and structurally at the single-cell level. Phylogenetic analysis demonstrates that the cocci cluster into an independent branch from other Alphaproteobacteria MTB, that is, within the Etaproteobacteria class in the Proteobacteria phylum. Statistical analysis reveals species-specific biomineralization of magnetosomal magnetite morphologies. This further confirms that magnetosome biomineralization is controlled strictly by the MTB cell and differs among species or strains. The post-mortem remains of MTB are often preserved as magnetofossils within sediments or sedimentary rocks, yet paleobiological and geological interpretation of their fossil record remains challenging. Our results indicate that magnetofossil morphology could be a promising proxy for retrieving paleobiological information about ancient MTB.     

Comparative Genome Analysis of Scutellaria baicalensis and Scutellaria barbata Reveals the Evolution of Active Flavonoid Biosynthesis

Scutellaria baicalensis (S. baicalensis) and Scutellaria barbata (S. barbata) are common medicinal plants of the Lamiaceae family. Both produce specific flavonoid compounds, including baicalein, scutellarein, norwogonin, and wogonin, as well as their glycosides, which exhibit antioxidant and antitumor activities. Here, we report chromosome-level genome assemblies of S. baicalensis and S. barbata with quantitative chromosomal variation (2n = 18 and 2n = 26, respectively). The divergence of S. baicalensis and S. barbata occurred far earlier than previously reported, and a whole-genome duplication (WGD) event was identified. The insertion of long terminal repeat elements after speciation might be responsible for the observed chromosomal expansion and rearrangement. Comparative genome analysis of the congeneric species revealed the species-specific evolution of chrysin and apigenin biosynthetic genes, such as the S. baicalensis-specific tandem duplication of genes encoding phenylalanine ammonia lyase and chalcone synthase, and the S. barbata-specific duplication of genes encoding 4-CoA ligase. In addition, the paralogous duplication, colinearity, and expression diversity of CYP82D subfamily members revealed the functional divergence of genes encoding flavone hydroxylase between S. baicalensis and S. barbata. Analyzing these Scutellaria genomes reveals the common and species-specific evolution of flavone biosynthetic genes. Thus, these findings would facilitate the development of molecular breeding and studies of biosynthesis and regulation of bioactive compounds.