Structural analysis of a trimeric assembly of the mitochondrial dynamin-like GTPase Mgm1.

The fusion of inner mitochondrial membranes requires dynamin-like GTPases, Mgm1 in yeast and OPA1 in mammals, but how they mediate membrane fusion is poorly understood. Here, we determined the crystal structure of Saccharomyces cerevisiae short Mgm1 (s-Mgm1) in complex with GDP. It revealed an N-terminal GTPase (G) domain followed by two helix bundles (HB1 and HB2) and a unique C-terminal lipid-interacting stalk (LIS). Dimers can form through antiparallel HB interactions. Head-to-tail trimers are built by intermolecular interactions between the G domain and HB2-LIS. Biochemical and in vivo analyses support the idea that the assembly interfaces observed here are native and critical for Mgm1 function. We also found that s-Mgm1 interacts with negatively charged lipids via both the G domain and LIS. Based on these observations, we propose that membrane targeting via the G domain and LIS facilitates the in cis assembly of Mgm1, potentially generating a highly curved membrane tip to allow inner membrane fusion

Modeling of System Energy of Rock Under Harmonic Vibro-Impact

Hamiltonian function is proposed and the modeling of system energy of rock under harmonic vibro-impact is undertaken in this study. The modeling includes two aspects, namely, energy equation of rock system with no damping and the one with damping. Also, the results of numerical simulation are presented. Four main control parameters are considered, including natural frequency of rock, impact frequency, impact force, damping coefficient.It is confirmed that the system energy of rock will increase with the increase of natural frequency impact frequency and impact force. While impact force, damping coefficient and stiffness of rock will mainly decide the vibration amplitude of system energy

Structure of the priming arabinosyltransferase AftA required for AG biosynthesis of Mycobacterium tuberculosis.

Arabinogalactan (AG) is an essential cell wall component in mycobacterial species, including the deadly human pathogen Mycobacterium tuberculosis. It plays a pivotal role in forming the rigid mycolyl-AG-peptidoglycan core for in vitro growth. AftA is a membrane-bound arabinosyltransferase and a key enzyme involved in AG biosynthesis which bridges the assembly of the arabinan chain to the galactan chain. It is known that AftA catalyzes the transfer of the first arabinofuranosyl residue from the donor decaprenyl-monophosphoryl-arabinose to the mature galactan chain (i.e., priming); however, the priming mechanism remains elusive. Herein, we report the cryo-EM structure of Mtb AftA. The detergent-embedded AftA assembles as a dimer with an interface maintained by both the transmembrane domain (TMD) and the soluble C-terminal domain (CTD) in the periplasm. The structure shows a conserved glycosyltransferase-C fold and two cavities converging at the active site. A metal ion participates in the interaction of TMD and CTD of each AftA molecule. Structural analyses combined with functional mutagenesis suggests a priming mechanism catalyzed by AftA in Mtb AG biosynthesis. Our data further provide a unique perspective into anti-TB drug discovery. </p

Fairness Evaluation of Landscape Justice in Urban Park Green Space: A Case Study of the Daxing Part of Yizhuang New Town, Beijing

Equitable distribution of urban park green space benefits public health and improves quality of life. From the perspective of landscape justice, this study establishes a subjective and objective comprehensive fairness evaluation method and analyzes the fairness of the spatial distribution of park green space in the Daxing part of Yizhuang New Town, Beijing and its relationship with the economic level of residents. The results show that: (1) the green space in the Daxing part of Yizhuang New Town is concentrated in the town center and distributed more sparsely in surrounding areas; (2) urban park green space is not equitable in quantity, area, disaster prevention and avoidance, or accessibility; (3) high-grade apartment complexes have higher quality of services than low-grade apartment complexes, and the number of parks, per capita park area, disaster prevention and avoidance, and park accessibility are all higher for high-grade than for low-grade apartment complexes. Medium-grade apartment complexes have a high level of green space services, and the number of parks, total area, and accessibility are 1.06, 2.58, and 1.13 times higher than those of high-grade apartment complexes, respectively. Conversely, disaster prevention and avoidance and park area per capita of medium-grade apartment complexes are lower than in high-grade apartment complexes, at 0.81 and 0.12 times, respectively. This study provides a new perspective for exploring society and landscape equity and concludes with suggestions for improving park green space public services

Acinetobacter baumannii Infection and IL-17 Mediated Immunity

Acinetobacter baumannii is a significant cause of severe hospital-acquired infections with a recent rise in multidrug-resistant infections involving traumatic wounds of military personnel. The interleukin-17 (IL-17) pathway is essential for neutrophil recruitment in response to a variety of pathogens, while the control of A. baumannii infection is known to be dependent on neutrophils. This suggests that IL-17 may play an important role in A. baumannii infection; however, this has yet to be studied. Here, we summarize the recent advances in understanding the host-pathogen interaction of A. baumannii and propose a potential role of the IL-17 pathway in generating a protective immune response

Porous ferroelectric materials for energy technologies:Current status and future perspectives

Ferroelectric materials have attracted significant interest due to their wide potential in energy harvesting, sensing, storage, and catalytic applications. For monolithic and dense ferroelectric materials, their performance figures of merit for energy harvesting and sensing are limited by their high relative permittivity, and their low surface area can limit piezo- or pyro-catalytic applications. As a result, the introduction of porosity into dense ferroelectric materials can enhance performance for a variety of piezoelectric and pyroelectric applications. In this review, the piezoelectric, pyroelectric, ferroelectric and mechanical properties of porous ferroelectrics are presented, and the fabrication processes to create porous ferroelectric materials are classified and discussed. Simulations of the poling process and resulting piezo- and pyro-electric properties are also described to understand the underlying science of these fascinating porous materials and develop new approaches towards materials design. Applications of porous ferroelectric materials in specific fields are then summarized. Finally, conclusions and future perspectives for porous ferroelectric materials are provided. This journal is </p

A Rapid Discrimination of Authentic and Unauthentic Radix Angelicae Sinensis Growth Regions by Electronic Nose Coupled with Multivariate Statistical Analyses

Radix Angelicae Sinensis, known as Danggui in China, is an effective and wide applied material in Traditional Chinese Medicine (TCM) and it is used in more than 80 composite formulae. Danggui from Minxian County, Gansu Province is the best in quality. To rapidly and nondestructively discriminate Danggui from the authentic region of origin from that from an unauthentic region, an electronic nose coupled with multivariate statistical analyses was developed. Two different feature extraction methods were used to ensure the authentic region and unauthentic region of Danggui origin could be discriminated. One feature extraction method is to capture the average value of the maximum response of the electronic nose sensors (feature extraction method 1). The other one is to combine the maximum response of the sensors with their inter-ratios (feature extraction method 2). Multivariate statistical analyses, including principal component analysis (PCA), soft independent modeling of class analogy (SIMCA), and hierarchical clustering analysis (HCA) were employed. Nineteen samples were analyzed by PCA, SIMCA and HCA. Then the remaining samples (GZM1, SH) were projected onto the SIMCA model to validate the models. The results indicated that, in the use of feature extraction method 2, Danggui from Yunnan Province and Danggui from Gansu Province could be successfully discriminated using the electronic nose coupled with PCA, SIMCA and HCA, which suggested that the electronic-nose system could be used as a simple and rapid technique for the discrimination of Danggui between authentic and unauthentic region of origin