Remodeling Isoprene Pyrophosphate Metabolism for Promoting Terpenoids Bioproduction

Terpenoids are the largest family of natural products.They are made from the building block isoprene pyrophosphate(IPP),and their bioproduction using engineered cell factories has received a great deal of attention.To date,the insufficient metabolic supply of IPP remains a great challenge for the efficient synthesis of terpenoids.In this work,we discover that the imbalanced metabolic flux distribution between the central metabolism and the IPP supply hinders IPP accumulation in Bacillus subtilis(B.subtilis).Therefore,we remodel the IPP metabolism using a series of genetically encoded two-input-multioutput(TIMO)circuits that are responsive to pyruvate or/and malonyl-CoA,resulting in an IPP pool that is significantly increased by up to four-fold.As a proof-of-concept validation,we design an IPP metabolism remodeling strategy to improve the production of three valuable terpenoids,including menaquinone-7(MK-7,4.1-fold),lycopene(9-fold),andβ-carotene(0.9-fold).In particular,the titer of MK-7 in a 50-L bioreactor reached 1549.6 mg·L^(-1),representing the highest titer reported so far.Thus,we propose a TIMO genetic circuits-assisted IPP metabolism remodeling framework that can be generally used for the synergistic fine-tuning of complicated metabolic modules to achieve the efficient bioproduction of terpenoids.

The roles of toll-like receptors in carcinogenesis and cancer immunotherapy

Toll-like receptors （TLRs） are probably the most important class of pattern-recognition receptors. Members of the TLR family play key roles in the both innate and adaptive immune responses. Recognition of pathogen-associated molecular patterns （PAMPs） by TLRs, either alone or in heterodimedzation with other TLR or non-TLR receptors, induces the production of signals that are responsible for the activation of genes important for an effective host defense, especially those of proinflammatory cytokines. Thus, TLRs are involved in the development of many pathological conditions including infectious diseases, tissue damage, and cancer especially. In this review, the contribution of TLRs to tumorgenesis is evaluated. We hope to provide new insight into the progression of cancer and more importantly into the potential for TLRs as targets of therapeutics.

Extraction Process of Volatile Oil of Artemisiae Scopariae Herba

[Objectives]To obtain the optimal extraction process parameters of volatile oil of Artemisiae Scopariae Herba.[Methods]The controlled variable method was used to take the extraction amount of volatile oil as the evaluation indicator,and the effects of single factor solid-to-liquid ratio,soaking time and extraction time on the yield rate of volatile oil were investigated.[Results]When the solid-to-liquid ratio reached 1∶12,the soaking time reached 3 h,and the extraction time reached 2 h,the yield of volatile oil was the highest.[Conclusions]The conditions of this process are stable and feasible,and it is expected to provide a certain reference for extracting volatile oil from Artemisiae Scopariae Herba.

The effect of parasitic charge on the output stability of MEMS gyroscopes

Output voltage drifting was observed in MEMS gyroscopes. Other than the quadrature error, frequency mismatch and quality factor, the dielectric parasitic charge was thought to be a major determinant. We studied the mechanism and variation of the parasitic charge in the MEMS gyroscopes, and analyzed the effect of the parasitic charge on the output stability. This phenomenon was extremely obvious in the Pyrex encapsulated MEMS gyroscopes. Due to the DC voltage required for the electrostatic actuation, the parasitic charge in the dielectric layer would accumulate and induce a residual voltage. This voltage had an impact on the resonant frequency of the gyroscopes, so as to affect the output stability. The theoretical studies were also confirmed by our experimental results. It was shown that the parasitic charge was harmful to the output stability of MEMS gyroscopes.

Submicrometer optical frequency combs based on SPPs metallic multi-ring resonators

Optical frequency combs(OFCs)have great potential in communications,especially in dense wavelength-division multiplexing.However,the size of traditional OFCs based on conventional optical microcavities or dispersion fibers is at least tens of micrometers,far larger than that of nanoscale electronic chips.Therefore,reducing the size of OFCs to match electronic chips is of necessity.Here,for the first time to our knowledge,we introduce surface plasmon polaritons(SPPs)to the construction of OFCs to realize a miniature device.The thickness of our device is reduced below 1μm.Though the presence of SPPs may induce ohmic and scattering loss,the threshold of the device is obtained as 9μW,comparable to the conventional device.Interestingly,the response time is 13.2 ps,much faster than the optical counterparts.This work provides a feasible strategy for the miniaturization of OFCs.

Engineering starch by enzymatic structure design for versatile applications in food industries:a critical review

As the second largest production material,starch has important value in textile,food,chemical and other fields.The shortcomings of natural starch can be solved,and its properties can be improved by modifying its structure,developing original properties,or introducing new functions,making it more suitable for certain application requirements.At present,the methods of starch modification mainly include chemical,physical,and enzymatic modification.In comparison with the two traditional modification methods(chemical and physical modification)mentioned above,enzymatic modification has the advantages of mild conditions,high substrate selectivity,and high product safety,and it is the most ideal green modification method.In this paper,we present an overview of the modified starch by enzymatic structure design.The modification process and mechanism for granule starch and gelatinized starch are summarized.Further,the difficulties encountered in starch modification by enzymatic modification were also analyzed.These analyses could pave a way for understanding and broadening the preparation and applications of modified starch,and provide theoretical references for the utilization of amylase in starch modification.

gp120-derived amyloidogenic peptides form amyloid fibrils that increase HIV-1 infectivity

Apart from mediating viral entry,the function of the free HIV-1 envelope protein(gp120)has yet to be elucidated.Our group previously showed that EP2 derived from oneβ-strand in gp120 can form amyloid fibrils that increase HIV-1 infectivity.Importantly,gp120 contains~30β-strands.We examined whether gp120 might serve as a precursor protein for the proteolytic release of amyloidogenic fragments that form amyloid fibrils,thereby promoting viral infection.Peptide array scanning,enzyme degradation assays,and viral infection experiments in vitro confirmed that manyβ-stranded peptides derived from gp120 can indeed form amyloid fibrils that increase HIV-1 infectivity.These gp120-derived amyloidogenic peptides,or GAPs,which were confirmed to form amyloid fibrils,were termed gp120-derived enhancers of viral infection(GEVIs).GEVIs specifically capture HIV-1 virions and promote their attachment to target cells,thereby increasing HIV-1 infectivity.Different GAPs can cross-interact to form heterogeneous fibrils that retain the ability to increase HIV-1 infectivity.GEVIs even suppressed the antiviral activity of a panel of antiretroviral agents.Notably,endogenous GAPs and GEVIs were found in the lymphatic fluid,lymph nodes,and cerebrospinal fluid(CSF)of AIDS patients in vivo.Overall,gp120-derived amyloid fibrils might play a crucial role in the process of HIV-1 infectivity and thus represent novel targets for anti-HIV therapeutics.

淀粉的胶体特性与调控

淀粉是由葡萄糖缩聚而成的一种天然高分子化合物,作为自然界来源非常丰富的一种多糖,是人体的主要能量来源与工业加工的重要原辅料.淀粉分子中含有的丰富羟基使其具有较强的亲水性,成糊后具有增稠稳定、黏接等作用,胶体特性显著.但是,天然淀粉因自身结构的局限性、分子链易重排,其应用范围和效果受到一定限制.因此,本文综述了淀粉颗粒结构和分子结构对其胶体特性的影响,阐述了通过物理、化学、生物改性及植物遗传育种等方式精准设计淀粉结构的原理和方法,实现淀粉胶体性能的调控,以期为淀粉胶体的科学应用提供参考.

粉质黏土地层桩侧劈裂注浆参数设计与效果评价

针对粉质黏土地层在役桩基础承载力不足问题,采用数值模拟和现场试验相结合的方法实现在役桩基注浆加固参数设计与加固效果评价。通过浆脉施加体积应变的方法建立注浆压力传递有限元模型,研究不同注浆工况下粉质黏土地层桩侧径向压力的分布规律,提出注浆参数设计方法。土压力随距离的衰减是非线性的,在一定的土体参数下注浆压力为2.0 MPa,注浆孔与桩侧距离为0.5 m时,传递到桩侧的径向压力较大。以京台高速改扩建现场桩基为模型,绘制不同工况下桩基承载力提升幅度等值线图,注浆加固后桩基承载力提高了30.3%~89.4%,为在役桩基加固效果提供参考。

Proximal and remote sensing in plant phenomics: 20 years of progress, challenges, and perspectives

Plant phenomics(PP)has been recognized as a bottleneck in studying the interactions of genomics and environment on plants,limiting the progress of smart breeding and precise cultivation.High-throughput plant phenotyping is challenging owing to the spatio-temporal dynamics of traits.Proximal and remote sensing(PRS)techniques are increasingly used for plant phenotyping because of their advantages in multi-dimensional data acquisition and analysis.Substantial progress of PRS applications in PP has been observed over the last two decades and is analyzed here from an interdisciplinary perspective based on 2972 publications.This progress covers most aspects of PRS application in PP,including patterns of global spatial distribution and temporal dynamics,specific PRS technologies,phenotypic research fields,working environments,species,and traits.Subsequently,we demonstrate how to link PRS to multi-omics studies,including how to achieve multi-dimensional PRS data acquisition and processing,how to systematically integrate all kinds of phenotypic information and derive phenotypic knowledge with biological significance,and how to link PP to multi-omics association analysis.Finally,we identify three future perspectives for PRS-based PP:(1)strengthening the spatial and temporal consistency of PRS data,(2)exploring novel phenotypic traits,and(3)facilitating multi-omics communication.

Design of the low-loss waveguide coil for interferometric integrated optic gyroscopes

With the development of manufacturing technology,the propagation loss of the planar waveguide is getting lower and lower,and the shot-noise-limited sensitivity of an HOG will be greatly improved.When the propagation loss is getting lower,improper coupling-out waveguide in the waveguide coil may lead to non-ignorable bending loss and crosstalk because of the small radius of curvature and X-junction.In this paper,different couplingout waveguides have been designed.After calculation and optimization by the beam propagation method,we found the proper coupling-out waveguide having relatively low propagation loss,which can improve the sensitivity of the HOG.