Selenious-β-lactoglobulin induces the apoptosis of human lung cancer A549 cells via an intrinsic mitochondrial pathway

In this study, the cytotoxic activity of selenious-β-lactoglobulin (Se-β-Lg) and the anticancer mechanism were investigated in human lung cancer A549 cells in vitro. MTT assay showed that Se-β-Lg at 200 μg/mL exhibited a significant suppression effect on A549 cells and the maximum inhibition rate reached 90% after 72 h treatment. Flow cytometry analysis revealed that 200 μg/mL of Se-β-Lg induced cell cycle arrest at G₀/G₁ phase. Cell apoptosis was induced via the generation of reactive oxygen species (ROS) and the decrease of mitochondrial membrane potential (ΔΨm) in a time-dependent manner. Furthermore, Se-β-Lg suppressed the expression of Bcl-2 and improved the level of Bax, leading to the release of cytochrome c and a higher expression of caspase-3 in A549 cells. In summary, Se-β-Lg could induce apoptosis in A549 cells via an intrinsic mitochondrial pathway and it might serve as a potential therapeutic agent for human lung cancer.     

基于土地利用格局变化的北京市生境质量时空演变研究

城市生境质量对生物多样性保护有至关重要的作用,以北京市为例分析2000—2015年北京市不同土地利用类型的空间分布特征和不同区域之间的差异,并借助In VEST-Habitat Quality模型评估了北京市4个时期(2000年、2005年、2010年和2015年)、4个区域(首都功能核心区、城市发展新区、城市功能拓展区、生态涵养发展区)的生境退化程度和生境质量变化情况。结果表明:(1)从2000年到2015年,建设用地增加了近40%,耕地、湿地是其快速扩张的主要来源,城市发展新区的建设用地增加了60%;(2)主要的生态用地(林地、草地、湿地)所占比例总体增加了5.71%,但是总体景观结构异质性减弱,斑块破碎化程度加大;(3)生境质量总体下降了2%,表现出明显的区域差异,首都功能核心区和生态涵养发展区的生境质量总值逐渐升高;生境退化度逐渐增加,最严重的区域在城市功能拓展区以及平原-山区交界地带。对区域生态服务价值评估的有益探索,为今后进一步城市景观格局的构建和优化提供依据和参考。     

Snake venomics – from low-resolution toxin-pattern recognition to toxin-resolved venom proteomes with absolute quantification

Introduction: Venoms are integrated phenotypes used by a wide range of organisms for predatory and defensive purposes. The study of venoms is of great interest in diverse fields, such as evolutionary ecology and biotechnology. Omics technologies have contributed to understanding the evolutionary mechanisms that molded snake venoms to their present-day structural and functional variability landscape.

Areas covered: This review article reflects on two recent implementations in venomics: absolute quantification of intact proteins by elemental mass spectrometry, and top-down molecular mass spectrometry.

Expert commentary: Leveraging on a new way of polyatomic interference removal, a triple quadrupole inductively coupled plasma mass spectrometry configuration has proven feasible for the absolute quantification of venom toxins via sulfur detection. A major advantage of this approach over quantitative molecular mass spectrometry techniques is that only a generic S-standard is required to quantify all the chromatographically separated sulfur-containing fractions. Top-down venomics is in its infancy but, due to recent hardware and software developments, is gaining momentum. Proteoform-resolved venom proteomes are needed to understand the spatio-temporal variability landscape underlying the adaptations that drive intraspecific venom evolution. Integrating top-down venomics and absolute proteoform quantification into a novel elemental and molecular mass spectrometry configuration will represent a quantitative leap in the study of individual venoms.     

INO80 participates in the pathogenesis of recurrent miscarriage by epigenetically regulating trophoblast migration and invasion

The INO80 complex, a SWI/SNF family chromatin remodeler, has regulatory effects on ESC self-renewal, somatic cell reprogramming and blastocyst development. However, the role of INO80 in regulating trophoblast cells and recurrent miscarriage (RM) remains elusive. To investigate the in vivo effects of Ino80 in embryo development, we disrupted Ino80 in C57 mice, which resulted in embryonic lethality. Silencing of Ino80 led to decreased survival capacity, migration and invasion of trophoblasts. Furthermore, RNA high-throughput sequencing (RNA-seq) revealed that Ino80 silencing closely resembled the gene expression changes in RM tissues. To investigate the mechanisms for these results, RNA-seq combined with high-throughput sequencing (ChIP-seq) was used in trophoblast cells, and it showed that Ino80 physically occupies promoter regions to affect the expression of invasion-associated genes. Last, Western blotting analyses and immunofluorescence staining revealed that the content of INO80 was reduced in RM patients compared to in healthy controls. This study indicates that INO80 has a specific regulatory effect on the viability, migration and invasion of trophoblast cells. Combined with its regulation of the expression of invasion-associated genes, it has been proposed that epigenetic regulation plays an important role in the occurrence of RM, potentially informing RM therapeutic strategies.     

Binding between elongation factor 1A and the 3ʹ-UTR of Chinese wheat mosaic virus is crucial for virus infection

The Chinese wheat mosaic virus (CWMV) genome consists of two positive-strand RNAs that are required for CWMV replication and translation. The eukaryotic translation elongation factor (eEF1A) is crucial for the elongation of protein translation in eukaryotes. Here, we show that silencing eEF1A expression in Nicotiana benthamiana plants by performing virus-induced gene silencing can greatly reduce the accumulation of CWMV genomic RNAs, whereas overexpression of eEF1A in plants increases the accumulation of CWMV genomic RNAs. In vivo and in vitro assays showed that eEF1A does not interact with CWMV RNA-dependent RNA polymerase. Electrophoretic mobility shift assays revealed that eEF1A can specifically bind to the 3ʹ-untranslated region (UTR) of CWMV genomic RNAs. By performing mutational analyses, we determined that the conserved region in the 3ʹ-UTR of CWMV genomic RNAs is necessary for CWMV replication and translation, and that the sixth stem-loop (SL-6) in the 3ʹ-UTR of CWMV genomic RNAs plays a key role in CWMV infection. We conclude that eEF1A is an essential host factor for CWMV infection. This finding should help us to develop new strategies for managing CWMV infections in host plants.     

Role for Rhizobium rhizogenes K84 cell envelope polysaccharides in surface interactions

Rhizobium rhizogenes strain K84 is a commercial biocontrol agent used worldwide to control crown gall disease. The organism binds tightly to polypropylene substrate and efficiently colonizes root surfaces as complex, multilayered biofilms. A genetic screen identified two mutants in which these surface interactions were affected. One of these mutants failed to attach and form biofilms on the abiotic surface although, interestingly, it exhibited normal biofilm formation on the biological root tip surface. This mutant is disrupted in a wcbD ortholog gene, which is part of a large locus predicted to encode functions for the biosynthesis and export of a group II capsular polysaccharide (CPS). Expression of a functional copy of wcbD in the mutant background restored the ability of the bacteria to attach and form normal biofilms on the abiotic surface. The second identified mutant attached and formed visibly denser biofilms on both abiotic and root tip surfaces. This mutant is disrupted in the rkpK gene, which is predicted to encode a UDP-glucose 6-dehydrogenase required for O-antigen lipopolysaccharide (LPS) and K-antigen capsular polysaccharide (KPS) biosynthesis in rhizobia. The rkpK mutant from strain K84 was deficient in O-antigen synthesis and exclusively produced rough LPS. We also show that strain K84 does not synthesize the KPS typical of some other rhizobia strains. In addition, we identified a putative type II CPS, distinct from KPS, that mediates cell-surface interactions, and we show that O antigen of strain K84 is necessary for normal cell-cell interactions in the biofilms.     

Condensation of DNA by basic protiens does not depend on protien composition

We have studied by electron microscopy the size and morphology of the complexes obtained with different DNAs (between 500 and 5243 base pairs long) and four different proteins: sea urchin histone H1; sea cucumber histone ?₀, chicken erythrocyte histone H5, and clupeine. Surprisingly, the type of protein used has only a marginal influence on the complexes formed. The molecular weight and topology of DNA do not show any influence. The size of the complexes depends strongly on the ratio of positive to negative charges and also on the ionic conditions. Our studies have been mainly carried out at a ratio of 0.4. Under these conditions the average thickness of rods and toroids observed varies between 165 Å at 1.5 mM salt to 290 Å at 100 mM salt, with minor variations around these values depending on the type of DNA and protein used. We conclude that the formation of DNA condensates is mainly determined by a balance of electrostatic and intermolecular forces, the influence of specific interactions is only marginal. This conclusion seems to apply not only to the complexes described here, but also to chromatin fibers and to DNA condensed by low molecular weight counterions and other compounds (polyamines, inorganic ions, ethanol, etc.). © 1994 John Wiley & Sons, Inc.