七鳃鳗——铁代谢研究的极佳模型

七鳃鳗历经5亿年的进化历程,所处的自然环境具有低温及铁含量较高等特点,且在变态发育过程中组织结构和生命机制已经发展出其独特的适应性的进化方式,这为人们进一步研究生命起源和进化提供了新的方向。铁是人体必需的营养素之一,在代谢过程中发挥重要的作用,但当过量时可能导致铁中毒。七鳃鳗体内游离铁含量很高,如变态前幼体的血清铁浓度是人类正常男性的149倍,幼体肝中的铁含量约是人类正常含量的2~3倍。七鳃鳗具有完备的生物化学系统耐受体内高浓度的游离铁,铁稳态的重要基因如转铁蛋白、铁蛋白重链、超氧化物歧化酶等基因高表达,提升了铁转运、铁储存及抗氧化能力。七鳃鳗具有IRE/IRP调控系统,是适应组织内高铁环境的重要保护机制。此外,七鳃鳗在变态发育过程中逐渐形成口腔腺,成为独特的铁代谢器官。本文主要介绍了七鳃鳗各组织铁的分布及适应体内高铁含量的潜在机制,为后续寻找调控铁代谢分子机制提供理论基础。

The component-activity interrelationship of cobalt-based bifunctional electrocatalysts for overall water splitting:Strategies and performance

Cobalt-based electrocatalysts take advantage of potentially harmonizable microstructure and flexible coupling effects compared to commercial noble metal-based catalytic materials.However,conventional water electrolysis systems based on cobalt-based monofunctional hydrogen evolution reaction(HER)or oxygen evolution reaction(OER)catalysts have certain shortcomings in terms of resource utilization and universality.In contrast,cobalt-based bifunctional catalysts(CBCs)have attracted much attention in recent years for overall water splitting systems because of their practicality and reduced preparation cost of electrolyzer.This review aims to address the latest development in CBCs for total hydrolysis.The main modification strategies of CBCs are systematically classified in water electrolysis to provide an overview of how to regulate their morphology and electronic configuration.Then,the catalytic performance of CBCs in total-hydrolysis is summarized according to the types of cobalt-based phosphides,sulfides and oxides,and the mechanism of strengthened electrocatalytic ability is emphasized through combining experiments and theoretical calculations.Future efforts are finally suggested to focus on exploring the dynamic conversion of reaction intermediates and building near-industrial CBCs,designing advanced CBC materials through micro-modulation,and addressing commercial applications.

Effects of lead pollution on soil microbial community diversity and biomass and on invertase activity

Lead(Pb)pollution is one of the most widespread and harmful environmental problems worldwide.Determination of changes in soil properties and microbial functional diversity due to land use is needed to establish a basis for remediation of soil pollution.This study aimed to investigate soils contaminated by Pb from different sources and to analyze the functional diversity and metabolism of soil microbial communities using Biolog technology.Pb pollution(>300 mg kg-1)significantly influenced the diversity and metabolic functions of soil microbial communities.Specifically,Pb contamination significantly reduced soil microbial biomass carbon(C)and nitrogen(N)levels and catalase activity while increasing invertase activity.Furthermore,Biolog EcoPlate assays revealed that Pb pollution reduced the general activities of soil microorganisms,suppressing their ability to utilize C sources.In Pb-contaminated areas lacking vegetation cover,Shannon,Simpson,and McIntosh diversity indices of soil microorganisms were significantly reduced.The microbial diversity and biomass C and N levels were affected by land use and soil properties,respectively,whereas soil enzyme activity was primarily affected by the interaction between land use and soil properties.Our results provide a reference and a theoretical basis for developing soil quality evaluation and remediation strategies.

Fast and deterministic optical phased array calibration via pointwise optimisation

Owing to the structural errors in the optical phased array,an initial random phase reduces the quality of the deflection beam.The most commonly applied approach to phase calibration is based on adaptive optics.However,adaptive optimisation approaches have slow convergence and low diffraction efficiency.We proposed a pointwise optimisation approach to achieve fast and accurate beam deflection.This approach conducts phase calibration,combining global traversal and local searches individually for each array element.We built a phase-calibration optical system containing a one-dimensional optical waveguide phase array for further verification and designed the relevant mechanics.The simulation and experimental results demonstrate that the pointwise optimisation approach accelerates the calibration process and improves the diffraction efficiency.

Lotus seedpod-inspired internal vascularized 3D printed scaffold for bone tissue repair

In the field of bone defect repair,3D printed scaffolds have the characteristics of personalized customization and accurate internal structure.However,how to construct a well-structured vascular network quickly and effectively inside the scaffold is essential for bone repair after transplantation.Herein,inspired by the unique biological structure of“lotus seedpod”,hydrogel microspheres encapsulating deferoxamine(DFO)liposomes were prepared through microfluidic technology as“lotus seeds”,and skillfully combined with a three-dimensional(3D)printed bioceramic scaffold with biomimetic“lotus”biological structure which can internally grow blood vessels.In this composite scaffold system,DFO was effectively released by 36%in the first 6 h,which was conducive to promote the growth of blood vessels inside the scaffold quickly.In the following 7 days,the release rate of DFO reached 69%,which was fundamental in the formation of blood vessels inside the scaffold as well as osteogenic differentiation of bone mesenchymal stem cells(BMSCs).It was confirmed that the composite scaffold could significantly promote the human umbilical vein endothelial cells(HUVECs)to form the vascular morphology within 6 h in vitro.In vivo,the composite scaffold increased the expression of vascularization and osteogenic related proteins Hif1-α,CD31,OPN,and OCN in the rat femoral defect model,significantly cutting down the time of bone repair.To sum up,this“lotus seedpod”inspired porous bioceramic 3D printed scaffold with internal vascularization functionality has broad application prospects in the future.

Improving seeking precision by utilizing ghost imaging in a semi-active quadrant detection seeker

Conventional semi-active laser guidance takes advantage of the laser designator to illuminate the stable and uniform laser spot on target precisely.The seeker collects the reflected light by a quadrant detector and outputs the relative position information to guide the missile to the illuminating laser spot.However,the designation and guidance accuracy could be jeopardized by the randomly drifting of laser spot caused by the instability of designation platform and air turbulence.In this work,ghost imaging technique is adapted to a quadrant detector semi-active seeker by utilizing structured illumination on the target.With a series of structured illumination masks,the signals from the quadrant detector are multiplexed to perform calculation of the target relative position as well as image reconstruction of the illuminated area simultaneously.Automatic target recognition methods could be further applied to the reconstructed image to calculate the designating error and correct the guidance.The results of simulation and experiment demonstrate that the proposed method could improve the guidance accuracy in many circumstances which would lead to attacking deviation if conventional semi-active laser guidance is used.

Protection of Immuno-Compromised Mice from Lethal Infection of Klebsiella pneumonia by rAAV2-BPI23-Fcγ1 Gene Transfer

In previous research, chimerical BPI23-Fcy1 gene which consisted of human bactericidal/permeability increasing protein （BPI） gene of encoding the functional N terminus （amino acid residues 1 to 199） of human BPI and Fcy1 gene of encoding the Fc segment of human immunoglobulin G1 was successfully reconstructed within a recombinant adeno-associated virus serotype 2 （rAAV2） vector as rAAV2-BPI23-Fcy1. Here, to evaluate the potentiality of applying gene therapy to gram negative bacterial （GNB） infection in high-risk patients, we investigated protection of immuno-compromised mice and immunocompetent mice from challenge with minimal lethal dose （MLD） Klebsiella pneumonia infection after rAAV2-BPI23-Fcy1 gene transferred. The results showed that the survival rate of rAAV2-BPI23-Fcy1 transferred immunocompetent mice as well as immuno-compromised mice （40.0% and 44.4%, respectively） were significant higher than that of corresponding control mice （6.7% and 4.4%, respectively）; the bacteria counting, level of endotoxin and proinflammatory cytokines in the rAAV2-BP123-Fcy1 transferred immuno-compromised mice were markedly lower than that of rAAV2-EGFP and rAAV2-Null transferred immuno- compromised mice. Our data suggest that rAAV2-BPI23-Fcy1 gene transferring offered immuno-compromised mice with resistance against GNB infection, so it is quite potential in preventing GNB infection of clinical high-risk patients. Cellular ＆ Molecular Immunology. 2008;5（6）：439-445.