Search

Quantum key distribution (QKD) can provide information theoretically secure key exchange even in the era of quantum computers. However, QKD requires the classical channel to be authenticated, the current method for which is pre-sharing symmetric keys. For a QKD network of n users, this method requires C n 2 = n (n − 1) / 2 pairs of symmetric keys to realize pairwise interconnection. In contrast, with the help of a mature public key infrastructure (PKI) and post-quantum cryptography (PQC) with quantum-resistant security, each user only needs to apply for one digital certificate from a certificate authority (CA) to achieve efficient and secure authentication for QKD. We need to assume only the short-term security of the PQC algorithm to achieve long-term security of the distributed keys. Here, we experimentally verified the feasibility, efficiency, and stability of the PQC algorithm in QKD authentication, and demonstrated the advantages when new users join the QKD network. Using the PQC public-key infrastructure, the nodes need to mutually trust only the CA to authenticate each other. QKD combined with PQC authentication will greatly promote and extend the application prospects of quantum-safe communication. [ABSTRACT FROM AUTHOR]

A series of podophyllotoxin derivatives (M1–M16) that were selectively acylated by various phenoxy acids at the C-4 position of podophyllotoxin were synthesized, and their biological activities were also evaluated. Among them, compound M4 showed the most potent anti-cancer activity against HeLa cells with an IC50 value of 1.64 ± 0.41 μM. Additionally, flow cytometry analysis results indicated that it could cause a remarkable cell cycle arrest at G2/M phase, but the effect on apoptosis inducing was not significant. Moreover, the expression of cell cycle relative protein CDK1 was up regulated while cyclin B1 and Cdc25C, two proteins required for mitotic initiation were down regulated. Furthermore, the confocal assay and extracellular polymerized tubulin expression analysis also demonstrated that M4 was a potent tubulin polymerization inhibitor and the effect was comparable to that of colchicine. Finally, docking simulation results showed that M4 could nicely bind to the colchicine binding site of tubulin which further comfirmed the tubulin inhibiton activity of M4. [ABSTRACT FROM AUTHOR]

Ancient living halotolerant bacteria and ancient DNA have been reported from bedded marine halite, but seldom from lacustrine halite of the geological age. A halotolerant bacterium (Haloalkaliphilic bacterium, designated as 3-4) was isolated from primary halite with abundant fluid inclusions. Primary halite crystallized in lacustrine Yunying Depression located in the northeastern Jianghan Basin of central China. Yunying Depression is an inland salt paleolake residing in a faulted basin formed during late Cretaceous/early Tertiary. Brine inclusions from the same layer of the salt that housed Haloalkaliphilic bacterium 3-4 are the middle-late Eocene primary halite crystals and have homogenization temperatures between 5.8 and 43.3 °C. The estimated age is between 33.9 and 48.6 Ma years old for these fluid inclusions, and this represents the long-term survivability of this microorganism Haloalkaliphilic bacterium 3-4. Sequence analysis of the partial fragment of 16S ribosomal DNA showed that the organism is similar to the lineage of Haloalkaliphilic bacterium and Oceanobacillus sp. The isolation of the microbe reinforces the long-term preservation possibility of life in extreme environment such as the fluid inclusions in halite. [ABSTRACT FROM AUTHOR]

Echium plantagineum L. (Boraginaceae) is an invasive species in Australia and contains medicinal shikonins in its roots. In this study, the hairy root lines of E. plantagineum were established using Agrobacterium rhizogenes strain ATCC15834 and confirmed by the amplification of the rolB gene. Results showed significant difference in shikonin production between the hairy root lines in the 1/2B5 and M9 media. The biomass of the lines in the 1/2B5 medium was fivefold of that in the M9 medium. However, the components of detected shikonins were similar in these two liquid media. By contrast, different accumulation profiles appeared in the hairy root lines. HPLC analysis revealed the presence of nine possible related compounds, including shikonins, and acetylshikonin was the most abundant shikonin derivative. The content of acetylshikonin in the 1/2B5 medium (36.25 mg/L on average) was twofold of that in the M9 medium. Our results showed that the hairy root cultures of E. plantagineum can be used in enhancing the production of potential pharmaceutical compounds, such as acetylshikonin. [ABSTRACT FROM AUTHOR]

Ethylene-responsive transcription factors (ERFs) belonging to the AP2/ERF family have diverse functions in plants. However, the functions of LeERF-1, a member of ERF family from the medicinal plant Lithospermum erythrorhizon, remain unclear. In this study, by cloning the promoter of LeERF-1, we found that the promoter region contained a number of potential regulatory motifs related to drought and pathogen resistances. Further transgenic studies showed that the heterologous overexpression of LeERF-1 in Arabidopsis displayed phenotypes of higher survival ratio, lower root inhibition rate, slow water loss in leaf discs, and smaller stomatal apertures under drought stress, compared with wild type (WT) of Arabidopsis. LeERF-1 transgenic Arabidopsis also displayed fewer chlorotic symptoms, lower incidence rates, and lower levels of bacterial proliferation on leaves after the inoculation of bacterial pathogen compared with WT. These results suggested that LeERF-1 can also confer drought and pathogen resistances. Our work provided a candidate gene with remarkable potential use in genetic engineering for stress resistance improvement in plants. [ABSTRACT FROM AUTHOR]

Cardiac remodeling is characterized by overactivity of the renin-angiotensin system (RAS) and withdrawal of vagal activity. We hypothesized that improving vagal activity could attenuate cardiac fibrosis induced by angiotensin II (Ang II) in vivo and in vitro. Rats were subjected to abdominal aorta constriction (AAC) with or without pyridostigmine (PYR) (31 mg/kg/d). After 8 weeks, PYR significantly decreased Ang II level, AT1 protein expression, and collagen deposition in cardiac tissue and improved heart rate variability, baroreflex sensitivity and cardiac function, which were abolished by atropine. In vitro, treatment of cardiac fibroblasts (CFs) with Ang II (10−7 M) increased cell proliferation, migration, transformation, and secretory properties, which were significantly diminished by acetylcholine (ACh, 10−6 M). Subsequently, Ang II significantly increased collagen type I expression as well as metalloproteinase (MMP)-2 expression and activity. Transforming growth factor (TGF)-β1 expression and Smad3 phosphorylation presented a similar trend. Notably, the knockdown of the acetylcholine M2 receptor by siRNA could abolish ACh anti-fibrotic action. These data implicated cholinesterase inhibitor can increase vagal activity and reduce local Ang II level, and ACh inhibit Ang II pro-fibrotic effects. Our findings suggested that the parasympathetic nervous system can serve as a promising target for cardiac remodeling treatment. [ABSTRACT FROM AUTHOR]