The Biosynthesis of the Benzoxazole in Nataxazole Proceeds via an Unstable Ester and has Synthetic Utility.

Heterocycles, a class of molecules that includes oxazoles, constitute one of the most common building blocks in current pharmaceuticals and are common in medicinally important natural products. The antitumor natural product nataxazole is a model for a large class of benzoxazole-containing molecules that are made by a pathway that is not characterized. We report structural, biochemical, and chemical evidence that benzoxazole biosynthesis proceeds through an ester generated by an ATP-dependent adenylating enzyme. The ester rearranges via a tetrahedral hemiorthoamide to yield an amide, which is a shunt product and not, as previously thought, an intermediate in the pathway. A second zinc-dependent enzyme catalyzes the formation of hemiorthoamide from the ester but, by shuttling protons, the enzyme eliminates water, a reverse hydrolysis reaction, to yield the benzoxazole and avoids the amide. These insights have allowed us to harness the pathway to synthesize a series of novel halogenated benzoxazoles.

Cytochrome P450 CYP6AE70 Confers Resistance to Multiple Insecticides in a Lepidopteran Pest, Spodoptera exigua.

Cytochrome P450 monooxygenases are associated with the detoxification of xenobiotics, and overexpression of P450 genes has been proven to be associated with insecticide resistance in insect species. Our previous study has revealed that multiple CYP6AE genes were significantly overexpressed in a resistant strain of Spodoptera exigua, and among these genes, CYP6AE70 was particularly highly expressed. However, the functional roles of the CYP6AE genes in insecticide resistance remain unknown in this pest. Here, we investigate the relationship between the CYP6AE genes and insecticide resistance by focusing on CYP6AE70. The expression of CYP6AE70 was increased after exposure to chlorpyrifos, cypermethrin, and deltamethrin. Ectopic overexpression of P450 in transgenic flies by the GAL4/UAS system dramatically enhanced the tolerance to these three insecticides. Furthermore, the recombinant CYP6AE70 was functionally expressed in Sf9 cells, and metabolic assays revealed that the recombinant P450 protein could efficiently metabolize chlorpyrifos, cypermethrin, and deltamethrin. Finally, molecular modeling and docking also showed that this P450 protein were tightly bound to the three insecticides. These results determine that the upregulation of CYP6AE genes results in resistance to multiple insecticides in S. exigua. This study improves our understanding of P450-mediated insecticide resistance and will help us to design more effective resistance management for pest control.

Velvet antler water extract protects porcine oocytes from lipopolysaccharide-induced meiotic defects.

Previous studies have demonstrated that lipopolysaccharide (LPS), as a central toxic factor of gram-negative bacteria, can induce oxidative stress and cellular inflammation to result in the impairment of female fertility in different organisms. Particularly, it has harmful effects on the oocyte quality and subsequent embryonic development. However, the approach concerning how to prevent oocytes from LPS-induced deterioration still remains largely unexplored. We assessed the effective influences of velvet antler water extract (VAWE) by immunostaining and fluorescence intensity quantification on the meiotic maturation, mitochondrial function and sperm binding ability of oocytes under oxidative stress. Here, we report that VAWE treatment restores the quality of porcine oocytes exposed to LPS. Specifically, LPS exposure contributed to the failed oocyte maturation, reduced sperm binding ability and fertilization capability by disturbing the dynamics and arrangement of meiotic apparatuses and organelles, including spindle assembly, chromosome alignment, actin polymerization, mitochondrial dynamics and cortical granule distribution, the indicators of oocyte nuclear and cytoplasmic maturation. Notably, VAWE treatment recovered these meiotic defects by removing the LPS-induced excessive ROS and thus inhibiting the apoptosis. Collectively, our study illustrates that VAWE treatment is a feasible strategy to improve the oocyte quality deteriorated by the LPS-induced oxidative stress.

Research and Application Progress of Vegetation Porous Concrete.

Vegetation porous concrete is a novel material that integrates concrete technology with plant growth, offering excellent engineering applicability and environmental friendliness. This material is mainly utilized in eco-engineering projects such as riverbank protection, architectural greening, and slope protection along roads. This paper systematically reviews the current research progress of vegetation porous concrete by collecting and analyzing the relevant literature from both domestic and international sources. It covers several aspects including the material components of vegetation porous concrete, such as aggregates, cementitious materials, chemical admixtures, and plant species, as well as aspects like mix design, workability, porosity, pH value, mechanical strength, and vegetative performance. Furthermore, the application of vegetation porous concrete in riverbank protection, slope protection along highways, and urban architecture is discussed, along with a prospective outlook on future research directions for vegetation porous concrete.

Strong 3D Printing by TPMS Injection.

3D printed objects are rapidly becoming prevalent in science, technology and daily life. An important question is how to obtain strong and durable 3D models using standard printing techniques. This question is often translated to computing smartly designed interior structures that provide strong support and yield resistant 3D models. In this paper we suggest a combination between 3D printing and material injection to achieve strong 3D printed objects. We utilize triply periodic minimal surfaces (TPMS) to define novel interior support structures. TPMS are closed form and can be computed in a simple and straightforward manner. Since TPMS are smooth and connected, we utilize them to define channels that adequately distribute injected materials in the shape interior. To account for weak regions, TPMS channels are locally optimized according to the shape stress field. After the object is printed, we simply inject the TPMS channels with materials that solidify and yield a strong inner structure that supports the shape. Our method allows injecting a wide range of materials in an object interior in a fast and easy manner. Results demonstrate the efficiency of strong printing by combining 3D printing and injection together.

Improved fat transplantation survival by using the conditioned medium of vascular endothelial growth factor transfected human adipose-derived stem cells.

Autologous fat transplantation has been applied widely in clinic. However, the low survival rate is still a problem to be solved. Studies shows that the human adipose-derived stem cells (ADSCs) transfected by vascular endothelial growth factor (VEGF) can improve the survival rate of autologous fat transplantation. Our study is to evaluate the effects of the conditioned medium of VEGF-transfected human adipose-derived stem cells (VEGF-ADSCs-CM) on fat transplantation. ADSCs were isolated and transfected with MOI = 40. The study was divided into three groups, VEGF-ADSCs-CM group, normal-ADSCs-CM group and control group. The conditioned media for VEGF-ADSCs-CM group and normal-ADSCs-CM group were collected, and then mixed with fat, with the mixtures being injected into the back of nude mice. On 4, 7, 15, 30, 60 days after transplantation, the grafts were evaluated on the wet weight, histology, ELISA and western blot. As the results revealed, the survival rate of VEGF-ADSCs-CM group was highest with the best fat cell morphology, and the VEGF secretion of VEGF-ADSCs-CM group was also highest. Therefore, our study demonstrates that VEGF-ADSCs-CM can improve the survival rate of fat transplantation effectively, and VEGF-ADSCs-CM can be regarded as an effective assisted method for fat transplantation.

Shape vocabulary: a robust and efficient shape representation for shape matching.

In this paper, a learning-based shape descriptor for shape matching is demonstrated. Formulated in a bag-of-words like framework, the proposed method summarizes the local features extracted from certain shape to generate a integrated representation. It contributes to the speed-up of shape matching, since the distance metric in the vector space analysis can be directly applied to compare the constructed global descriptors, eliminating the time consuming stage of local feature matching. Similar to the philosophy in spatial pyramid matching, a strategy for feature division is applied in the phase of encoded feature pooling and vocabulary learning, which helps to construct a more discriminative descriptor incorporating both global and local information. Also, a local contour-based feature extraction method is designed for 2D shapes, while significant properties of the local contours are inspected for the design of feature division rules. The designed local feature extraction method and the feature division rules manage to reduce the variances of shape representation due to the changes in rotation. In addition to 2D shape, we also present a simple and natural method to extend the proposed method to the scenario of 3D shape representation. The proposed shape descriptor is validated on several benchmark data sets for evaluating 2D and 3D shape matching algorithms, and it is observed that the investigated shape descriptor maintains superior discriminative power as well as high time efficiency.