摘要：Proliferating cell nuclear antigen (PCNA), encoded by POL30 in Saccharomyces cerevisiae, is a key component of DNA metabolism. Here, a library consisting of 304 PCNA mutants was designed and constructed to probe the contribution of each residue to the biological function of PCNA. Five regions with elevated sen sitivity to DNA damaging reagents were identified using high-throughput phe no type screening. Using a series of genetic and biochemical analyses, we demonstrated that one particular mutant, K168A, has defects in the DNA damage tolerance (DDT) pathway by disrupting the interaction between PCNA and Rad5. Subsequent domain analysis showed that the PCNA-Rad5 interaction is a prerequisite for the function of Rad5 in DDT. Our study not only provides a resource in the form of a library of versatile mutants to study the functions of PCNA, but also reveals a key residue on PCNA (K168) which highlights the importance of the PCNA-Rad5 interaction in the template switching (TS) pathway.

摘要：The site-specific incorporation of the noncanonical amino acid(ncAA)into proteins via genetic code expansion(GCE)has enabled the development of new and powerful ways to learn,regulate,and evolve biological functions in ***,cellular biosynthesis of ncAA-containing proteins with high efficiency and fidelity is a formidable *** this review,we summarize up-to-date progress towards improving the efficiency and orthogonality of GCE and enhancing intracellular compatibility of introduced translation machinery in the living cells by creation and optimization of orthogonal translation components,constructing genomically recoded organism(GRO),utilization of unnatural base pairs(UBP)and quadruplet codons(four-base codons),and spatial separation of orthogonal translation.

摘要：Plants adapt to their changing environments by sensing and responding to physical,biological,and chemical *** to their sessile lifestyles,plants experience a vast array of external stimuli and selectively perceive and respond to specific *** repurposing the logic circuitry and biological and molecular components used by plants in nature,genetically encoded plant-based biosensors(GEPBs)have been developed by directing signal recognition mechanisms into carefully assembled outcomes that are easily *** allow for in vivo monitoring of biological processes in plants to facilitate basic studies of plant growth and *** are also useful for environmental monitoring,plant abiotic and biotic stress management,and accelerating design-build-test-learn cycles of plant *** the advent of synthetic biology,biological and molecular components derived from alternate natural organisms(e.g.,microbes)and/or de novo parts have been used to build *** this review,we summarize the framework for engineering different types of *** then highlight representative validated biological components for building plant-based biosensors,along with various applications of plant-based biosensors in basic and applied plant science ***,we discuss challenges and strategies for the identification and design of biological components for plant-based biosensors.

摘要：Rapid and sensitive detection of various analytes is in high *** from its application in genome editing,CRISPR-Cas also shows promises in nucleic acid detection *** further exploit the potential of CRISPR-Cas for detection of diverse analytes,we present a versatile biosensing platform that couples the excellent affinity of aptamers for broad-range analytes with the collateral single-strand DNA cleavage activity of CRISPR-Cas12 *** demonstrated that the biosensors developed by this platform can be used to detect protein and small molecule in human serum with a complicated background,i.e.,the tumor marker alpha fetoprotein and cocaine with the detection limits of 0.07 fmol/L and 0.34 lmol/L,respectively,highlighting the advantages of simplicity,sensitivity,short detection time,and low cost compared with the state-of-the-art biosensing ***,this biosensing platform with plug-and-play design show great potential in the detection of diverse analytes.

摘要：鞭毛和纤毛独特的运动模式(如鞭毛的平面/螺旋波形式推进和纤毛的二维/三维不对称搏动)在众多生物的生命活动中起到至关重要的作用,这也启发了诸多仿生设计,尤其对于微型机器人系统。然而,与自然界中微生物能够从统一化的9+2轴丝生物结构中进化出多种运动模式不同的是,当前的仿生学仍然没有有效的工程策略去实现这样的智慧。在此,我们通过研究鞭毛和纤毛的内部结构及其内在驱动机制,推导出了一个统一的物理模型来描述微管弯曲及其所构建的宏观鞭毛/纤毛运动。基于该模型,我们进而提出了基于三通道的管状驱动概念,并相应地通过杆嵌入铸造工艺制造了一个三通道的管状驱动器。通过编程不同通道的驱动模式,这一管状驱动器不仅可以再现自然界中多样的二维及三维鞭毛/纤毛运动,还可以延展出更多的非对称纤毛搏动模式以实现低雷诺数下的有效推进。该研究加深了我们对微生物推进机制的理解,为仿生系统的设计提供了新灵感,并有望在广泛的工程领域中寻找到重要的应用场景。

摘要：Microbial synthesis of carotenoids is a highly desirable alternative to plant extraction and chemical *** this study,we investigated multidimensional strategies to improve the carotenoid synthesis in the industrial workhorse of Saccharomyces ***,we rewired the yeast central metabolism by optimizing non-oxidative glycolysis pathway for an improved acetyl-CoA ***,we restricted the consumption of farnesyl pyrophosphate(FPP)by the down-regulation of squalene synthase using the PEST ***,we further explored the human lipid binding/transfer protein saposin B(hSapB)-mediated metabolic sink for an enhanced storage of lipophilic ***,the copper-induced GAL expression system was engineered to function in the yeast-peptone-dextrose medium for an increased biomass *** combining the abovementioned strategies,the final engineered yeast produced 166.79±10.43 mg/Ⅰβ-carotene in shake flasks,which was nearly 5-fold improvement of the parental carotenoid-producing ***,we envision that multidimensional strategies reported here might be applicable to other hosts for the future industrial development of carotenoid synthesis from renewable feedstocks.