Developing high-efficiency base editors by combining optimized synergistic core components with new types of nuclear localization signal peptide

The clustered regularly interspaced short palindromic repeats(CRISPR)–CRISPR-associated protein(Cas) system has been widely used for genome editing. In this system, the cytosine base editor(CBE) and adenine base editor(ABE) allow generating precise and irreversible base mutations in a programmable manner and have been used in many different types of cells and organisms. However, their applications are limited by low editing efficiency at certain genomic target sites or at specific target cytosine(C) or adenine(A) residues. Using a strategy of combining optimized synergistic core components, we developed a new multiplex super-assembled ABE(sABE) in rice that showed higher base-editing efficiency than previously developed ABEs. We also designed a new type of nuclear localization signal(NLS) comprising a FLAG epitope tag with four copies of a codon-optimized NLS(F4NLS^(r2)) to generate another ABE named F4NLS-sABE. This new NLS increased editing efficiency or edited additional A at several target sites. A new multiplex super-assembled CBE(sCBE) and F4NLS^(r2) involved F4NLS-sCBE were also created using the same strategy. F4NLS-sCBE was proven to be much more efficient than sCBE in rice. These optimized base editors will serve as powerful genome-editing tools for basic research or molecular breeding in rice and will provide a reference for the development of superior editing tools for other plants or animals.

Study on a noninvasive method for rapid screening Human Serum albumin injectables by Raman spectroscopy

Human serum albumin(HSA)injectable product is a severely afflicted area on drug safety due to its high price and restricted supply.Raman spectroscopy performances high specificity on HSA detection and it is even possible to determine HSA injectable products noninvasively.In this study,we developed a noninvasive rapid screening method for of HSA injectable products by using portable Raman spectrometer.Qualitative models were established by using principal component analysis combined with classical least squares(PCA-CLS)algorithm,while quanti-tative model was established by using partial least squares(PLS)algorithm.Model transfer in different instruments of both the same and different apparatus modules was further discussed in this paper.A total of 34 HSA injectable samples collected from markets were used for verification.The identification results showed 100%accuracy and the predicted concentrations of those identified as true HSA were consistent with their labeled concentrations.The quantitative results also indicated that model transfer was excellent in the same apparatus modules of Raman spectrometer at all concentration levels,and still good enough in the different apparatus modules although the relative standard deviation(RSD)value showed a little increasing trend at low HSA concentration level.In conclusion,the method was proved to be feasible and efficient for screening HSA injections,especially on its screening speed and the consideration of glass containers.Moreover,with inspiring results on the model transfer,the method could be used as a universal screening mean to different Raman instruments.

Equivalent Response Estimation of Structural Systems Subjected to Long-Period Ground Motion

Long-period ground motion has become an important consideration because of the increasing number of large and long-period structures.Therefore,a thorough investigation on the formation and characteristics of longperiod ground motion is desirable for engineering applications.In this work,an analytical study is performed to examine the effect of several parameters and the combining mode for equivalent harmonic components on the dynamic response of systems.The results of the work show that the harmonic components in equivalent ground motion are evidently influenced by the intensity rise time,duration,phase and combining mode.Moreover,the long-period ground motions are simplified and simulated by separate harmonic components through proper combination.The findings of the work are believed to be useful in the selection of input ground motion in structural seismic analysis.

Comparison of the Network Structural Characteristics of Calcium Signaling Pathway in Cerebral Ischemia after Intervention by Different Components of Chinese Medicine

Objective:To explore the network control mechanism of the calcium signaling pathway in cerebral ischemic injury after intervention by the main components of Qingkailing(清开灵),i.e.Baicalin,Jasminoidin and their combination.Methods:Thirty mice were randomly divided into 5 groups,a baicalin group,a Jasminoidin group,a baicalin plus Jasminoidin group,a nimodipine group,and a model group(n=6).The global cerebral ischemia-reperfusion mouse model was established.The mice were administrated respectively by injection of baicalin,Jasminoidin,mixture of baicalin and Jasminoidin,and nimodipine into the caudal vein,with the model group given no any drug.Three hours after operation,the brain was removed and sectioned.After calculation of cerebral ischemic area by 2,3,5-triphenyltetrazolium staining,the percentage of infarct volume was calculated.The total RNA of the mouse brain tissue was extracted to obtain the whole genome expression profile,and the differentially expressed genes related to the calcium signaling pathway was analyzed with Bayesian network structures.Results:Compared with the model group,the ischemic area was significantly reduced in the baicalin group,the Jasminoidin group,the Baicalin plus Jasminoidin group(all P<0.05).The ischemic area in the baicalin plus Jasminoidin group was smaller than the other three groups(all P<0.01).In the gene regulatory network structures of calcium signaling pathway,the average length and equitability were the highest in the baicalin plus Jasminoidin group,followed by the nimodipine group.Conclusion:Compared with a single component,combination of Baicalin and Jasminoidin can more obviously intervene in the overall expression of calcium signaling pathway,and the mechanism is related with the aggregation characteristic of the gene expression network.