Polaritonic coherent perfect absorption based on self-hybridization of a quasi-bound state in the continuum and exciton.

Enhancement of light-matter interactions is of great importance for many nanophotonic devices, and one way to achieve it is to feed energy perfectly to the strongly coupled system. Here, we propose gap-perturbed dimerized gratings based on bulk WS2 for flexible control of the strong coupling or self-hybridization of a quasi-bound state in the continuum (quasi-BIC) and exciton. The simulation results show that when a gap perturbation is introduced into the system resulting in the Brillouin zone folding, BIC transforms into quasi-BIC whose quality factor (Q-factor) is related to the value of gap perturbation. The strong coupling results in the anti-crossover behavior of the absorption spectra, and thus a Rabi splitting energy of 0.235 eV is obtained. With the assistance of temporal coupled-mode theory, the conditions for the strong critical coupling are obtained, and finally successful achievement of polaritonic coherent perfect absorption in the proposed system. This work could provide ideas for enhancing light-matter interactions and strong theoretical support for all-optical tuning and modulation.

Hybrid molecules with potential in vitro antiplasmodial and in vivo antimalarial activity against drug-resistant Plasmodium falciparum.

Malaria is a tropical disease, leading to around half a million deaths annually. Antimalarials such as quinolines are crucial to fight against malaria, but malaria control is extremely challenged by the limited pipeline of effective pharmaceuticals against drug-resistant strains of Plasmodium falciparum which are resistant toward almost all currently accessible antimalarials. To tackle the growing resistance, new antimalarial drugs are needed urgently. Hybrid molecules which contain two or more pharmacophores have the potential to overcome the drug resistance, and hybridization of quinoline privileged antimalarial building block with other antimalarial pharmacophores may provide novel molecules with enhanced in vitro and in vivo activity against drug-resistant (including multidrug-resistant) P falciparum. In recent years, numerous of quinoline hybrids were developed, and their activities against a panel of drug-resistant P falciparum strains were screened. Some of quinoline hybrids were found to possess promising in vitro and in vivo potency. This review emphasized quinoline hybrid molecules with potential in vitro antiplasmodial and in vivo antimalarial activity against drug-resistant P falciparum, covering articles published between 2010 and 2019.

The novel HLA-DPB1*1500:01N allele, identified by Sanger dideoxy nucleotide sequencing in a Chinese individual.

HLA-DPB1*1500:01N differs from HLA-DPB1*05:01:01:01 by one nucleotide in exon 3.

Recent advances of tetrazole derivatives as potential anti-tubercular and anti-malarial agents.

Tetrazole, a bioisostere of the carboxylic acid group, can replace the carboxyl group in drugs to increase the lipophilicity, bioavailability and reduce side effects. Tetrazole derivatives possess a broad-spectrum of biological properties including anti-tubercular and anti-malarial activities, and some tetrazole-based compounds have already been used in clinics for the treatment of various diseases. Therefore, tetrazole is an important pharmacophore in the development of new drugs. This review covers the recent advances of tetrazole derivatives as potential anti-tubercular and anti-malarial agents, and the structure-activity relationship is also discussed for the further rational design of tetrazole derivatives.

[Location and role of protein kinase Cα in parthenogenetic and tetraploid preimplantation embryonic development in mouse].

Protein kinase C (PKC) is a critical molecule in cellular signal transduction in mammals. It is involved in many biological processes in embryonic development, including nuclear remodeling, cell cycle adjustment and cellular polarity regulation. The present study aimed to observe the location of PKCα, an important isozyme of PKC, in fertilized, parthenogenetic and tetraploid preimplantation embryos, and compare the expression of PKCα during embryonic compaction in Kunming mice. The location of PKCα was detected by immunochemistry and laser confocal microscopy. Western blot was performed to quantify PKCα expression during embryonic compaction in the three kinds of embryos. In the experiment, fertilized embryos were flushed from oviduct or uterus at 45, 52, 69, 76 and 93 h after injection of human chorionic gonadotrophin (hCG); parthenogenetic embryos were collected by SrCl2 activation of oocytes for 6 h; and tetraploid embryos were produced by electrofusion of 2-cell embryos. Embryos were fixed at different developmental stages for immunofluorescent staining. 8-cell/4-cell embryos and morula were lysed for Western blot. The results showed that PKCα had similar location pattern in different embryos. It was distributed mainly in the nuclear aggregating around chromatin at different developmental stages. However, PKCα expressed strongly in the interphase than in mitotic blastomere. Before embryonic compaction, PKCα was localized at the blastomere boundary. At late blastocyst stage of fertilized embryos, PKCα was localized only in the polar trophoblast, but not in other trophoblast. At late stage of pathenogenetic blastocyst, there was no clear PKCα signal in the polar trophoblast. Tetraploid embryos had larger blastomere than other embryos and compacted after 4-cell stage, but not after 8-cell stage. Meanwhile, there was PKCα signal at the blastomere boundary at 4-cell stage. Our results showed that the expression of PKCα lasted through all the preimplantation stage. Although there were different expression levels among different stages, the expression increased around embryonic compaction. Quantification of expression of PKCα by Western blot demonstrated that the expression increased after compaction, indicating that the compaction was possibly dependent on the relocation of PKCα. Moreover, it was shown that the second relocation of PKCα occurred during the blastocyst formation. PKCα had different expression patterns in the three kinds of preimplantation embryos. However, the effects of PKCα on embryonic development started in early stage. There must be a necessary connection between PKCα relocation and cell adhesion starting at embryonic compaction.

[Dynamic changes of microtubule in parthenogenetic and in vitro fertilized preimplantation embryos in mouse.].

In this study we detected dynamic changes and function of beta-tubulin, a subtype of microtubule, during the first cleavage period in mouse parthenogenetic and in vitro fertilized embryos. Firstly, we compared the developmental potential of in vitro fertilized, parthenogenetic, and in vivo fertilized embryos in culture. Then, the dynamic changes of beta-tubulin and nucleus in parthenogenetic and in vitro fertilized preimplantation embryos were detected by immunofluorescence and confocal microscopy to analyze the role of microtubules in meiotic division and embryonic development. The results indicated that the development rate of in vivo fertilized embryos was significantly higher than that of in vitro fertilized or parthenogenetic embryos (P<0.05). However, there was no significant difference in developmental potential between in vitro fertilized and parthenogenetic embryos. During in vitro fertilization, oocyte was activated when sperm entered it. Oocyte resumed the second meiotic division. Condensed maternal chromosomes aligning at the equator of the spindle were pulled to the spindle poles by kinetochore microtubules in anaphase. Furthermore, in telophase, there were microtubules between the two sets of decondensed maternal chromosomes. One set formed the second polar body (Pb(2)), which was extruded to the perivitelline space. The other set formed female pronucleus. Meanwhile, 5-8 h after fertilization, sperm chromatin condensed and decondensed to form male pronucleus. Microtubule composed mesosome and cytaster remodeling around male and female pronuclei to form long microtubules, which pull the pronuclei to get close. During 4-6 h parthenogenetic activation, SrCl(2) activated oocytes to resume meiosis. As a consequence, sister chromatids were pulled to spindle poles. Cytochalasin B, which was applied in the medium, inhibited the extrusion of Pb(2). Two haploid pronuclei in the cytoplasm were connected by microtubules. Compared with that in in vitro fertilization, oocyte is easier to be activated in parthenogenetic activation. Chemical activation is more efficient than sperm penetration in in vitro fertilization as indicated by earlier and better remodeling of the microtubules.

Enhancement of waste activated sludge dewaterability by electro-chemical pretreatment.

The potential effects of electro-chemical conditioning on sludge dewatering treatments and its mechanism were investigated in this study. Capillary suction time (CST) and specific resistance to filtration (SRF) were used to evaluate sludge dewaterability. Extracellular polymeric substance (EPS) content and sludge disintegration degree (DD(SCOD)) were also determined in an attempt to explain the observed changes in sludge dewaterability. The results indicated that application of considered low electrolysis voltages (<20 V) enhanced sludge dewaterability, while it exceeded 30 V, the dewaterability of sludge was significantly deteriorated. Also, electrolysis pretreatment slightly enhanced sludge dewaterability with short electrolysis time (<20 min), while it significantly deteriorated sludge dewaterability with long electrolysis time (>30 min). The optimal electrolysis voltage and electrolysis time to give preferable dewaterability characteristics were found to be 15-20 V, and 15-20 min, respectively, which generated sludge with optimal EPS content (15-20mg/L) and DD(SCOD) (1.3-2.0%).

[Preparation and identification of type specific and conformation dependent HPV16 L1 protein monoclonal antibody.].

AIM: To generate type specific and conformation dependent monoclonal antibodies against human papillomavirus 16 major capsid L1 protein (HPV16 L1). METHODS: HPV16 L1 protein was expressed by modified insect-baculovirus expression system and purified by ProBond(TM); purification system in nature conditions. BALB/c mice were immunized with the purified HPV16 L1 protein. Hybridoma technique was used to prepare the hybridoma cell lines. Positive colonies were screened by ELISA. The non-denaturing electrophoresis and Western blot methods were used for detecting the conformation dependent antibodies. Immunocytochemistry was used to confirm the type specific of the antibodies. The sub-class, isotype and titer were also identified respectively. RESULTS: One hybridoma cell line named 2E3 was obtained which can constantly secret type-specific and conformation-dependent HPV16 L1 mAb. The titers of the antibody are 1:800 in the cell culture medium and 1:12 800 in ascetic fluid. The sub-class and isotype were IgG1kappa. The antibody could selectively recognize non-denaturing HPV16 L1 protein and there was no cross-reaction with HPV18, HPV58 and HPV11 L1 protein. CONCLUSION: One cell line which secretes type specific and conformation dependent HPV16 L1 monoclonal antibody is successfully generated. This monoclonal antibody can be used in study HPV16 L1 protein epitope.

Expression of human papillomavirus type 16 L1 protein in transgenic tobacco plants.

To develop a plant expression system for the production of the human papillomavirus type 16 (HPV16) vaccine, we investigated whether the HPV16 L1 protein can be expressed in tobacco plants and whether it can be used as the cheapest form of edible vaccine. The HPV16 L1 coding sequence was amplified by PCR using specific primers from the plasmid pGEM-T-HPV16 containing the template sequence, and subcloned into the intermediate vector pUCmT and binary vector pBI121 consecutively to obtain the plant expression plasmid pBI-L1. The T-DNA regions of the pBI-L1 binary vector contained the constitutive Cauliflower mosaic virus (CaMV) 35S promoter and the neomycin phosphotransferase npt II gene, which allowed the selection of transformed plants using kanamycin. The tobacco plants were transformed by co-cultivating them, using the leaf disc method, with Agrobacterium tumefaciens LBA4404, which harbored the plant expression plasmid. The regenerated transgenic tobacco plants were selected using kanamycin, and confirmed by PCR. The results of the Southern blot assay also showed that the HPV16 L1 gene was integrated stably into the genome of the transformed tobacco plants. The Western blot analysis showed that the transformed tobacco leaves could express the HPV16 L1 protein. Furthermore, it was demonstrated by ELISA assay that the expressed protein accounted for 0.034%-0.076% of the total soluble leaf protein, was able to form 55 nm virus-like particles compatible with HPV virus-like particle (VLP), and induced mouse erythrocyte hemagglutination in vitro. The present results indicate that the HPV16 L1 protein can be expressed in transgenic tobacco plants and the expressed protein possesses the natural features of the HPV16 L1 protein, implying that the HPV16 L1 transgenic plants can be potentially used as an edible vaccine.