Developing an efficient and visible prime editing system to restore tobacco 8-hydroxy-copalyl diphosphate gene for labdane diterpene Z-abienol biosynthesis.

Prime editing (PE) is a versatile CRISPR-Cas based precise genome-editing platform widely used to introduce a range of possible base conversions in various organisms. However, no PE systems have been shown to induce heritable mutations in tobacco, nor in any other dicot. In this study, we generated an efficient PE system in tobacco that not only introduced heritable mutations, but also enabled anthocyanin-based reporter selection of transgene-free T1 plants. This system was used to confer Z-abienol biosynthesis in the allotetraploid tobacco cultivar HHDJY by restoring a G>T conversion in the NtCPS2 gene. High levels of Z-abienol were detected in the leaves of homozygous T1 plants at two weeks after topping. This study describes an advance in PE systems and expands genome-editing toolbox in tobacco, even in dicots, for use in basic research and molecular breeding. And restoring biosynthesis of Z-abienol in tobacco might provide an efficient way to obtain Z-abienol in plants.

Biological Effects of EGCG@MOF Zn(BTC)4 System Improves Wound Healing in Diabetes.

Tea contains high levels of the compound epigallocatechin gallate (EGCG). It is considered an important functional component in tea and has anti-cancer, antioxidant, and anti-inflammatory effects. The eight phenolic hydroxyl groups in EGCG's chemical structure are the basis for EGCG's multiple biological effects. At the same time, it also leads to poor chemical stability, rendering EGCG prone to oxidation and isomerization reactions that change its original structure and biological activity. Learning how to maintain the activity of EGCG has become an important goal in understanding the biological activity of EGCG and the research and development of tea-related products. Metal-organic frameworks (MOFs) are porous materials with a three-dimensional network structure that are composed of inorganic metals or metal clusters together with organic complexes. MOFs exploit the porous nature of the material itself. When a drug is an appropriate size, it can be wrapped into the pores by physical or chemical methods; this allows the drug to be released slowly, and MOFs can also reduce drug toxicity. In this study, we used MOF Zn(BTC)4 materials to load EGCG and investigated the sustained release effect of EGCG@MOF Zn(BTC)4 and the biological effects on wound healing in a diabetic mouse model.

Genome Engineering in Plant Using an Efficient CRISPR-xCas9 Toolset With an Expanded PAM Compatibility.

The CRISPR-Cas9 system enables simple, rapid, and effective genome editing in many species. Nevertheless, the requirement of an NGG protospacer adjacent motif (PAM) for the widely used canonical Streptococcus pyogenes Cas9 (SpCas9) limits the potential target sites. The xCas9, an engineered SpCas9 variant, was developed to broaden the PAM compatibility to NG, GAA, and GAT PAMs in human cells. However, no knockout rice plants were generated for GAA PAM sites, and only one edited target with a GAT PAM was reported. In this study, we used tRNA and enhanced sgRNA (esgRNA) to develop an efficient CRISPR-xCas9 genome editing system able to mutate genes at NG, GAA, GAT, and even GAG PAM sites in rice. We also developed the corresponding xCas9-based cytosine base editor (CBE) that can edit the NG and GA PAM sites. These new editing tools will be useful for future rice research or breeding, and may also be applicable for other related plant species.

A leucine-rich repeat-receptor-like kinase gene SbER2-1 from sorghum (Sorghum bicolor L.) confers drought tolerance in maize.

BACKGROUND: ERECTA (ER) is a leucine-rich repeat-receptor-like kinase gene (LRR-RLK) encoding a protein isolated from Arabidopsis. Although the regulatory functions of ER genes have been widely explored in plant development and disease resistance, their roles in drought stress responses remain to be clarified. RESULTS: In this study, we cloned and characterized two ER genes, SbER1-1 and SbER2-1, from the drought-tolerant model plant sorghum (Sorghum bicolor L.). Under drought stress, the two genes were expressed in the leaves and stems but not in the roots, and SbER2-1 transcript accumulation in the stem was increased. SbER2-1 was localized both on the plasma membrane and in the chloroplast. Moreover, SbER2-1 expression in Arabidopsis and maize conferred increased drought tolerance, especially in regard to water-use efficiency, increasing the net photosynthetic rate in maize under drought stress. Based on RNA-Seq analysis together with the physiological data, we conclude that the transgenic maize plants have upregulated phenylpropanoid metabolism and increased lignin accumulation under drought stress. CONCLUSIONS: Our results demonstrate that SbER2-1 plays an important role in response to drought stress. Furthermore, photosynthetic systems and phenylpropanoid metabolism are implicated in SbER2-1-mediated drought stress tolerance mechanisms. The use of genetic engineering to regulate SbER2-1 expression in plants and to breed new varieties tolerant to drought is a research field full of potential.

[Efficacy and safety of telbivudine treatment to block mother-to-child transmission of hepatitis B virus: a meta-analysis].

OBJECTIVE: To evaluate the efficacy and safety of telbivudine treatment in pregnant patients with chronic hepatitis B to block mother-to-child transmission of hepatitis B virus (HBV). METHODS: Medline and the Chinese Biomedical Literature Database were searched for studies of HBV, mother-to-child transmission, and telbivudine. Of the 68 potentially relevant publications, eight randomized controlled trials (RCTs) conformed to the inclusion and exclusion criteria. Following data extraction, a meta-analysis was carried out with RevMan5.1 software. RESULTS: Seven of the eight RCTs were in Chinese, and the remaining study was in English but carried out at a Chinese site. The RCTs comprised a total of 678 subjects, including 352 cases and 326 controls. Infants born to telbivudine-treated mothers had a significantly lower rate of HBsAg positivity and HBV DNA positivity at birth than the control group of infants (odds ratio (OR) = 0.27, 95% confidence interval (CI): 0.17, 0.43, P less than 0.00001; OR = 0.14, 95% CI: 0.06, 0.32, P less than 0.00001). Infants born to telbivudine-treated mothers also had significantly lower rates of mother-to-child transmitted HBV at 6 months (OR = 0.06, 95% CI: 0.02, 0.22, P less than 0.00001; OR = 0.05, 95% CI: 0.01, 0.25, P = 0.0003) and 12 months (OR = 0.13, 95% CI: 0.03, 0.56, P = 0.007; OR = 0.08, 95% CI: 0.02, 0.37, P = 0.001) after birth. The pre-telbivudine treatment levels of HBV DNA were not significantly different between pregnant women in the telbivudine-treated group and the control group (OR = 0.12, 95% CI: 0.00, 0.24, P = 0.04), but the HBV DNA levels were significantly lower in the telbivudine-treated group of pregnant women prior to delivery (OR = -3.92, 95% CI: -4.90, -2.95, P less than 0.00001). There was no evidence of telbivudine treatment being associated with more adverse side effects or complications during pregnancy or in the infant (OR = 1.72, 95% CI: 0.68, 4.38, P = 0.25; OR=0.69, 95% CI: 0.04, 11.24, P = 0.80). CONCLUSION: Telbivudine treatment effectively and safely prevents mother-to-child transmission of HBV from chronically infected mothers with a high degree of infectivity late in pregnancy.

[Construction of MyD88-Pseudomonas aeruginosa epitope DNA vaccine and its expression in eukaryotic cells].

AIM: To construct the MyD88-Pseudomonas aeruginosa epitope vaccine and study its expression in eukaryotic cells. METHODS: To design and synthesize an epigene containing three B cell epitopes of OprF and one foreign "promiscuous" T cell epitope by overlapping extension PCR. tPA signal encoding sequence was amplified by PCR and then it was inserted into the 5' terminus of the epigene to construct tPA-OprF. tPA-OprF and MyD88 were cloned into the expression vector pIRES and the recombinant plasmid pIRES-tPAOprF-MyD88 was constructed. The recombinant plasmid was transfected into COS-7 cells by electroporation. The expression protein of tPA-OprF and MyD88 was detected by Western blot. RESULTS: The recombinant plasmid pIRES-tPA-OprF-MyD88 was successfully constructed. Western blot analysis indicated the tPA-OprF fusion protein was expressed in supertanant of COS-7 cells and MyD88 protein in COS-7 cells. CONCLUSION: The recombinant plasmid pIRES-tPA-OprF-MyD88 has been successfully constructed and tPA-OprF and MyD88 protein can be highly expressed in transfected cells. It may be used as a potential candidate of preventive vaccine of pseudomonas aeruginosa.