Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Effects of artificial aging on physiological quality and cell ultrastructure of maize (Zea mays L.)

‘Qiule 368’ (flour maize) and ‘Zhengdan 958’ (flint maize) seeds were artificially aged at 46 °C and 95% relative humidity to investigate the changes in physiological quality of maize seeds during aging. The vigor of the seeds, their reactive oxygen species (ROS) content, cell membrane status, antioxidant enzyme system, and cellular ultrastructure were all investigated. The results showed that the germination energy, germination rate, superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities decreased during artificial aging, whereas the content of malondialdehyde (MDA), hydrogen peroxide (H2O2), superoxide anion (O2·–), and carbonyl protein as well as relative electrical conductivity (REC) increased during artificial aging. SOD and CAT activities showed highly significant negative correlation with aging time (p < 0.01), MDA, H2O2, O2·– content and REC showed highly significant positive correlation with aging time (p < 0.01), whereas POD activity showed significant negative correlation with aging time (p < 0.05). After aging, the cell membrane ruptured, and negative changes in amyloplast and protein bodies and in liposomes were all observed. This study provided guidelines for the meaningful study of changes in maize seed physiological quality during storage

Potential threat of Chlorpyrifos to human liver cells via the caspase-dependent mitochondrial pathways

Chlorpyrifos (CPF) has been widely used around the world as a pesticide for both agricultural and residential application. Although various studies have reported toxicity and health-related effects from CPF exposure, the potential threat and the molecular mechanism of CPF toxicity to human liver have not been well-characterized. In this study, we identify cytotoxicity of CPF to human normal liver cells in vitro. We demonstrate that the viability of QSG7701 cells is inhibited by CPF in a time- and concentration-dependent manner. Intracellular biochemical assays showed that CPF-induced apoptosis of QSG7701 cells concurrent with a decrease in the mitochondrial membrane potential, the release of cytochrome c into the cytosol, up-regulate the expression level of Bax/Bcl-2 and a marked activation of caspase-9/-3. These results indicate that CPF has a potential risk to human liver that can induce apoptosis of human liver cells through caspase-dependent mitochondrial pathways

Photopatterning of self-assembled poly (ethylene) glycol monolayer for neuronal network fabrication

The ability to culture individual neurons and direct their connections on functional interfaces provides a platform for investigating information processing in neuronal networks. Numerous methods have been used to design ordered neuronal networks on microelectrode arrays (MEAs) for neuronal electrical activities recording. However, so far, no method has been implemented, which simultaneously provides high-resolution neuronal patterns and low-impedance microelectrode. To achieve this goal, we employed a chemical vapor-deposited, non-fouling poly (ethylene) glycol (PEG) self-assembled monolayer to provide a cell repellant background on the MEAs. Photolithography, together with plasma etching of the PEG monolayer, was used to fabricate different patterns on MEAs. No electrode performance degradation was observed after the whole process. Dissociated cortical neurons were cultured on the modified MEAs, and the patterns were maintained for more than 3 weeks. Spontaneous and evoked neuronal activities were recorded. All of the results demonstrate this surface engineering strategy allows successful patterning of neurons on MEAs, and is useful for future studies of information processing in defined neuronal networks on a chip

Melt electrowriting (MEW)-PCL composite Three-Dimensional exosome hydrogel scaffold for wound healing

While mesenchymal stem cell-derived exosomes hold substantial potential in wound healing, challenges persist in terms of large-scale production and activity of 2D-culture derived exosome, as well as addressing their inactivation and loss during application. 3D exosomes can be produced more efficiently and possess higher activity. However, there lacks a delivery patch mimicking nanofibrous architecture of the extracellular matrix while facilitating the in situ delivery of exosomes, thereby minimizing dissipation of exosomes and accelerating the process of wound healing. In this study, we devised a controllable GelMA hydrogel-combined Melt Electrowriting (MEW)-PCL scaffold for in situ 3D-exosome release. We showed that biocompatible scaffolds prepared by MEW have a simulated extracellular matrix with a highly controllable arrangement of nanofibers that can support cell adhesion, proliferation and differentiation. Through cell proliferation, scratch assay, and tube formation experiments, we verified that 3D exosomes could effectively stimulate cell proliferation, migration, and tube formation, with dose-dependent effects. In vivo outcomes exhibited accelerated re-epithelialization, improved collagen maturation, and enhanced angiogenesis. Our findings suggest that 3D-cultured exosomes within the scaffold significantly enhance wound repair. This innovative delivery strategy opens up new avenues for the application of MSC-derived exosomes in wound healing

5′-<i>Epi</i>-SPA-6952A, a new insecticidal 24-membered macrolide produced by S<i>treptomyces diastatochromogenes</i> SSPRC-11339

<p>A new 24-membered macrolide, 5′-<i>epi</i>-SPA-6952A (<b>1</b>), was isolated from the cultured broth of <i>Streptomyces diastatochromogenes</i>. The structure was elucidated by means of spectroscopic methods and comparing with literature data of the known 24-membered macrolide SPA-6952A. Compound <b>1</b> was found to show significant insecticidal activity against oriental armyworm(<i>Mythimna separata</i> Walker) with LC₅₀ value of 10.26 mg/L.</p