Background: PI3K/AKT is a vital signaling pathway in humans. Recently, several PI3K/AKT inhibitors were reported to have the ability to reverse cancer multidrug resistance (MDR); however, specific targets in the PI3K/AKT pathways and the mechanisms associated with MDR have not been found because many of the inhibitors have multiple targets within a large candidate protein pool. AKT activation is one presumed mechanism by which MDR develops during cancer treatment. Methods: The effects of inhibiting PI3K 110α and 110β by BAY-1082439 treatment and CRISPR/Cas9 knockout were examined to determine the possible functions of BAY-1082439 and the roles of PI3K 110α and 110β in the reversal of MDR that is mediated by the downregulation of P-gp and BCRP. Inhibition of AKT with GSK-2110183 showed that the downregulation of P-gp and BCRP is independent of generalized AKT inactivation. Immunofluorescence, immunoprecipitation, MTT, flow cytometry and JC-1 staining analyses were conducted to study the reversal of MDR that is mediated by P-gp and BCRP in cancer cells. An ATPase assay and a structural analysis were also used to analyze the potential mechanisms by which BAY-1082439 specifically targets PI3K 110α and 110β and nonspecifically influences P-gp and BCRP. Results: By inhibiting the activation of the PI3K 110α and 110β catalytic subunits through both the administration of BAY-1082439 and the CRISPR/Cas9 deletion of Pik3ca and Pik3cb, the ATP-binding cassette transporters P-gp/ ABCB1 and BCRP/ABCG2 were downregulated, thereby reestablishing the drug sensitivity of human epidermoid carcinoma and non-small cell lung cancer (NSCLC) MDR cells. Inhibition of AKT did not reverse the MDR mediated by P-gp or BCRP. The ABC family proteins and AKT may play MDR-enhancing roles independently. Conclusions: The reversal of the dual functions of ABC-transporter-mediated and AKT-activation-enhanced MDR through the inhibition or knockout of PI3K 110α or 110β promises to improve current strategies based on combined drug treatments to overcome MDR challenges.

A facile electrochemical aptasensor based on a novel signal amplification strategy was employed for sensitive and selective detection of streptomycin for the first time. The aptasensor was prepared by sequentially dripping a gold nanoparticle-functionalized magnetic multi-walled carbon nanotube (Au@MWCNTs-Fe 3 O 4 ) composite and nanoporous PtTi (NP-PtTi) alloy onto a glassy carbon electrode (GCE) surface. The NP-PtTi alloy with a uniform nanoporous structure was successfully fabricated by selectively de-alloying Al from a PtTiAl alloy in HCl solution. The results demonstrated that the Au@MWCNTs-Fe 3 O 4 /NP-PtTi composite not only showed a remarkable synergistic effect towards the aptasensor, but also provided a beneficial immobilization platform for the streptomycin aptamer carrier.Under optimal conditions, a wide linear range from 0.05 to 100 ng mL À1 and a detection limit of 7.8 pg mL À1 were obtained. The designed aptasensor showed an excellent analytical performance with good reproducibility, high selectivity and stability. Finally, the proposed aptasensor was successfully used for the detection of streptomycin in a real sample.

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The Teosinte branched 1/Cycloidea/Proliferating cell factor (TCP) domain is an evolutionarily conserved DNA binding domain unique to the plant kingdom. To date, the functions of TCPs have been well studied, but the threedimensional structure of the TCP domain is lacking. Here, we have determined the crystal structure of the TCP domain from OsPCF6. The structure reveals that the TCP domain adopts three short b-strands followed by a helix-loop-helix structure, distinct from the canonical basic helix-loop-helix structure. This folded domain shows high structural similarity to the ribbonhelix-helix (RHH) transcriptional repressors, a family of DNA binding proteins with a conserved 3D structural motif (RHH fold), indicating that TCPs could be reclassified as RHH proteins. Our work will provide insight toward a better understanding of the mechanisms underlying TCP protein function.

Vaccination is one of the most effective approaches in the prevention and control of disease worldwide. Oral vaccination could have wide applications if effective protection cannot be achieved through traditional (eg, parenteral) routes of vaccination. However, oral administration is hampered by the difficulties in transferring vaccines in vivo. This has led to the development of materials such as carriers with potential adjuvant effects. Considering the requirements for selecting adjuvants for oral vaccines as well as the advantages of nanoparticle/microparticle materials as immune effectors and antigen conveyors, synthetic materials could improve the efficiency of oral vaccination. In this review, nanoparticles and microparticles with adjuvant characteristics are described with regard to their potential importance for oral immunization, and some promising and successful modification strategies are summarized.

Lipolytic enzymes are essential biocatalysts in food processing as well as pharmaceutical and pesticide industries, catalyzing the cleavage of ester bonds in a variety of acyl chain substrates. Here, we report the crystal structure of an esterase from the deep-sea hydrothermal vent of the East Pacific Rise (EprEst). The X-ray structure of EprEst in complex with the ligand, acetate, has been determined at 2.03 Å resolution. The structure reveals a unique spatial arrangement and orientation of the helix cap domain and α/β hydrolase domain, which form a substrate pocket with preference for short-chain acyl groups. Molecular docking analysis further demonstrated that the active site pocket could accommodate p-nitrophenyl (pNP) carboxyl ligands of varying lengths (≤6 C atoms), with pNP-butyrate ester predicted to have the highest binding affinity. Additionally, the semirational design was conducted to improve the thermostability of EprEst by enzyme engineering based on the established structure and multiple sequence alignment. A mutation, K114P, introduced in the hinge region of the esterase, which displayed increased thermostability and enzyme activity. Collectively, the structural and functional data obtained herein could be used as basis for further protein engineering to ultimately expand the scope of industrial applications of marine-derived lipolytic enzymes.

The crop production of quinoa (Chenopodium quinoa Willd.), the only plant meeting basic human nutritional requirements, is affected by drought stress. To better understand the drought tolerance mechanism of quinoa, we screened the drought-tolerant quinoa genotype “Dianli 129” and studied the seedling leaves of the drought-tolerant quinoa genotype after drought and rewatering treatments using transcriptomics and targeted metabolomics. Drought-treatment, drought control, rewatering-treated, and rewatered control were named as DR, DC, RW, and RC, respectively. Among four comparison groups, DC vs. DR, RC vs. RW, RW vs. DR, and RC vs. DC, we identified 10,292, 2,307, 12,368, and 3 differentially expressed genes (DEGs), and 215, 192, 132, and 19 differentially expressed metabolites (DEMs), respectively. A total of 38,670 genes and 142 pathways were annotated. The results of transcriptome and metabolome association analysis showed that gene-LOC110713661 and gene-LOC110738152 may be the key genes for drought tolerance in quinoa. Some metabolites accumulated in quinoa leaves in response to drought stress, and the plants recovered after rewatering. DEGs and DEMs participate in starch and sucrose metabolism and flavonoid biosynthesis, which are vital for improving drought tolerance in quinoa. Drought tolerance of quinoa was correlated with gene expression differences, metabolite accumulation and good recovery after rewatering. These findings improve our understanding of drought and rewatering responses in quinoa and have implications for the breeding of new drought-tolerance varieties while providing a theoretical basis for drought-tolerance varieties identification.