AAV13 Enables Precise Targeting of Local Neural Populations

As powerful tools for local gene delivery, adeno-associated viruses (AAVs) are widely used for neural circuit studies and therapeutical purposes. However, most of them have the characteristics of large diffusion range and retrograde labeling, which may result in off-target transduction during in vivo application. Here, in order to achieve precise gene delivery, we screened AAV serotypes that have not been commonly used as gene vectors and found that AAV13 can precisely transduce local neurons in the brain, with a smaller diffusion range than AAV2 and rigorous anterograde labeling. Then, AAV13-based single-viral and dual-viral strategies for sparse labeling of local neurons in the brains of C57BL/6 or Cre transgenic mice were developed. Additionally, through the neurobehavioral test in the ventral tegmental area, we demonstrated that AAV13 was validated for functional monitoring by means of carrying Cre recombinase to drive the expression of Cre-dependent calcium-sensitive indicator. In summary, our study provides AAV13-based toolkits for precise local gene delivery, which can be used for in situ small nuclei targeting, sparse labeling and functional monitoring.     

Antiviral Effect of Isoquercitrin against Influenza A Viral Infection via Modulating Hemagglutinin and Neuraminidase

Isoquercitrin (IQC) is a component abundantly present in many plants and is known to have an anti-viral effect against various viruses. In this study, we demonstrate that IQC exhibits strong anti-influenza A virus infection, and its effect is closely related to the suppression of hemagglutinin (HA) and neuraminidase (NA) activities. We used green fluorescent protein-tagged Influenza A/PR/8/34 (H1N1), A/PR/8/34 (H1N1), and HBPV-VR-32 (H3N2) to evaluate the anti-IAV effect of IQC. The fluorescence microscopy and fluorescence-activated cell sorting analysis showed that IQC significantly decreases the levels of GFP expressed by IAV infection, dose-dependently. Consistent with that, IQC inhibited cytopathic effects by H1N1 or H3N2 IAV infection. Immunofluorescence analysis confirmed that IQC represses the IAV protein expression. Time-of-addition assay showed that IQC inhibits viral attachment and entry and exerts a strong virucidal effect during IAV infection. Hemagglutination assay confirmed that IQC affects IAV HA. Further, IQC potently reduced the NA activities of H1N1 and H3N2 IAV. Collectively, IQC prevents IAV infection at multi-stages via virucidal effects, inhibiting attachment, entry and viral release. Our results indicate that IQC could be developed as a potent antiviral drug to protect against influenza viral infection.     

Performance Analysis of a HT-PEMFC System with 6FPBI Membranes Doped with Cross-Linkable Polymeric Ionic Liquid

In this paper, a high-temperature proton-exchange membrane fuel cell (HT-PEMFC) system using fluorine-containing polybenzimidazole (6FPBI) composite membranes doped with cross-linkable polymer ionic liquid (cPIL) is developed and studied. The reliability of the model is verified by a comparison with the experimental data. The performance of the HT-PEMFC system using 6FPBI membranes with different levels of cPIL is analyzed. The results show that when the HT-PEMFC uses 6FPBI membranes with a cPIL content of 20 wt % (6FPBI-cPIL 20 membranes), the single cell power density is 4952.3 W·m−2. The excessive cPIL content will lead to HT-PEMFC performance degradation. The HT-PEMFC system using the 6FPBI-cPIL 20 membranes shows a higher performance, even at higher temperatures and pressures, than the systems using 6FPBI membranes. In addition, the parametric study results suggest that the HT-PEMFC system should be operated at a higher inlet temperature and hydrogen pressure to increase system output power and efficiency. The oxygen inlet pressure should be reduced to decrease the power consumption of the ancillary equipment and improve system efficiency. The proposed model can provide a prediction for the performance of HT-PEMFC systems with the application of phosphoric-acid-doped polybenzimidazole (PA-PBI) membranes.     

Chromosome-Level Genome Assembly of a Fragrant Japonica Rice Cultivar ‘Changxianggeng 1813’ Provides Insights into Genomic Variations between Fragrant and Non-Fragrant Japonica Rice

East Asia has an abundant resource of fragrant japonica rice that is gaining increasing interest among both consumers and producers. However, genomic resources and in particular complete genome sequences currently available for the breeding of fragrant japonica rice are still scarce. Here, integrating Nanopore long-read sequencing, Illumina short-read sequencing, and Hi-C methods, we presented a high-quality chromosome-level genome assembly (~378.78 Mb) for a new fragrant japonica cultivar ‘Changxianggeng 1813’, with 31,671 predicated protein-coding genes. Based on the annotated genome sequence, we demonstrated that it was the badh2-E2 type of deletion (a 7-bp deletion in the second exon) that caused fragrance in ‘Changxianggeng 1813’. Comparative genomic analyses revealed that multiple gene families involved in the abiotic stress response were expanded in the ‘Changxianggeng 1813’ genome, which further supported the previous finding that no generalized loss of abiotic stress tolerance associated with the fragrance phenotype. Although the ‘Changxianggeng 1813’ genome showed high genomic synteny with the genome of the non-fragrant japonica rice cultivar Nipponbare, a total of 289,970 single nucleotide polymorphisms (SNPs), 96,093 small insertion-deletion polymorphisms (InDels), and 8690 large structure variants (SVs, >1000 bp) were identified between them. Together, these genomic resources will be valuable for elucidating the mechanisms underlying economically important traits and have wide-ranging implications for genomics-assisted breeding in fragrant japonica rice.     

Function-Related Asymmetry of the Interactions between Matrix Loops and Conserved Sequence Motifs in the Mitochondrial ADP/ATP Carrier

The ADP/ATP carrier (AAC) plays a central role in oxidative metabolism by exchanging ATP and ADP across the inner mitochondrial membrane. Previous experiments have shown the involvement of the matrix loops of AAC in its function, yet potential mechanisms remain largely elusive. One obstacle is the limited information on the structural dynamics of the matrix loops. In the current work, unbiased all-atom molecular dynamics (MD) simulations were carried out on c-state wild-type AAC and mutants. Our results reveal that: (1) two ends of a matrix loop are tethered through interactions between the residue of triplet 38 (Q38, D143 and Q240) located at the C-end of the odd-numbered helix and residues of the [YF]xG motif located before the N-end of the short matrix helix in the same domain; (2) the initial progression direction of a matrix loop is determined by interactions between the negatively charged residue of the [DE]G motif located at the C-end of the short matrix helix and the capping arginine (R30, R139 and R236) in the previous domain; (3) the two chemically similar residues D and E in the highly conserved [DE]G motif are actually quite different; (4) the N-end of the M3 loop is clamped by the [DE]G motif and the capping arginine of domain 2 from the two sides, which strengthens interactions between domain 2 and domain 3; and (5) a highly asymmetric stable core exists within domains 2 and 3 at the m-gate level. Moreover, our results help explain almost all extremely conserved residues within the matrix loops of the ADP/ATP carriers from a structural point of view. Taken together, the current work highlights asymmetry in the three matrix loops and implies a close relationship between asymmetry and ADP/ATP transport.     

BR-Mediated Protein S-Nitrosylation Alleviated Low-Temperature Stress in Mini Chinese Cabbage (Brassica rapa ssp. pekinensis)

Brassinosteroids (BRs), a novel plant hormone, are widely involved in plant growth and stress response processes. Nitric oxide (NO), as an important gas signaling molecule, can regulate target protein activity, subcellular localization and function in response to various stresses through post-translational S-nitrosylation modifications. However, the relationship between BR and NO in alleviating low-temperature stress of mini Chinese cabbage remains unclear. The hydroponic experiment combined with the pharmacological and molecular biological method was conducted to study the alleviating mechanism of BR at low temperature in mini Chinese cabbage. The results showed that low temperature inhibited the growth of mini Chinese cabbage seedlings, as evidenced by dwarf plants and yellow leaves. Treatment with 0.05 mg/L BR and 50 µM NO donor S-nitrosoglutathione (GSNO) significantly increased the leaf area, stem diameter, chlorophyll content, dry and fresh weight and proline content. Meanwhile, the malondialdehyde (MDA) content in 0.05 mg/L BR- and 50 µM GSNO-treated leaves were significantly lower than those in other treated leaves under low-temperature conditions. In addition, BR and GSNO applications induced an increase in NO and S-nitrosothiol (SNO) levels in vivo under low-temperature stress. Similarly, spraying BR after the elimination of NO also increased the level of S-nitrosylation in vivo, while spraying GSNO after inhibiting BR biosynthesis decreased the level of NO and SNO in vivo. In contrast, the S-nitrosoglutathione reductase (BrGSNOR) relative expression level and GSNOR enzyme activity were downregulated and inhibited by BR treatment, GSNO treatment and spraying BR after NO clearance, while the relative expression level of BrGSNOR was upregulated and GSNOR enzyme activity was also increased when spraying GSNO after inhibiting BR synthesis. Meanwhile, the biotin switch assay showed that exogenous BR increased the level of total nitrosylated protein in vivo under low-temperature stress. These results suggested that BR might act as an upstream signal of NO, induced the increase of NO content in vivo and then induced the protein S-nitrosylation modification to alleviate the damage of mini Chinese cabbage seedlings under low-temperature stress.     

Cyt-C Mediated Mitochondrial Pathway Plays an Important Role in Oocyte Apoptosis in Ricefield Eel (Monopterus albus)

Apoptosis plays a key role in the effective removal of excessive and defective germ cells, which is essential for sequential hermaphroditism and sex change in vertebrates. The ricefield eel, Monopterus albus is a protogynous hermaphroditic fish that undergoes a sequential sex change from female to male. Previous studies have demonstrated that apoptosis is involved in sex change in M. albus. However, the apoptotic signaling pathway is unclear. In the current study, we explored the underlying mechanism of apoptosis during gonadal development and focused on the role of the mitochondrial apoptosis signaling pathway in sex change in M. albus. Flow cytometry was performed to detect apoptosis in gonads at five sexual stages and ovary tissues exposed to hydrogen peroxide (H₂O₂) in vitro. Then the expression patterns of key genes and proteins in the mitochondrial pathway, death receptor pathway and endoplasmic reticulum (ER) pathway were examined. The results showed that the apoptosis rate was significantly increased in the early intersexual stage and then decreased with the natural sex change from female to male. Quantitative real-time PCR revealed that bax, tnfr1, and calpain were mainly expressed in the five stages. ELISA demonstrated that the relative content of cytochrome-c (cyt-c) in the mitochondrial pathway was significantly higher than that of caspase8 and caspase12, with a peak in the early intersexual stage, while the levels of caspase8 and caspase12 peaked in the late intersexual stage. Interestingly, the Pearson’s coefficient between cyt-c and the apoptosis rate was 0.705, which suggests that these factors are closely related during the gonadal development of M. albus. Furthermore, the cyt-c signal was found to be increased in the intersexual stage by immunohistochemistry. After incubation with H₂O₂, the mRNA expression of mitochondrial pathway molecules such as bax, apaf-1, and caspase3 increased in ovary tissues. In conclusion, the present results suggest that the mitochondrial apoptotic pathway may play a more important role than the other apoptotic pathways in sex change in M. albus.     

Precision Killing of Sinoporphyrin Sodium-Mediated Photodynamic Therapy against Malignant Tumor Cells

Photodynamic therapy (PDT) has significant advantages in the treatment of malignant tumors, such as high efficiency, minimal invasion and less side effects, and it can preserve the integrity and quality of the organs. The power density, irradiation time and photosensitizer (PS) concentration are three main parameters that play important roles in killing tumor cells. However, until now, the underlying relationships among them for PDT outcomes have been unclear. In this study, human malignant glioblastoma U-118MG and melanoma A375 cells were selected, and the product of the power density, irradiation time and PS concentration was defined as the total photodynamic parameter (TPP), in order to investigate the mechanisms of PS sinoporphyrin sodium (DVDMS)-mediated PDT (DVDMS-PDT). The results showed that the survival rates of the U-118MG and A375 cells were negatively correlated with the TPP value in the curve, and the correlation exactly filed an e-exponential function. Moreover, according to the formula, we realized controllable killing effects of the tumor cells by randomly adjusting the three parameters, and we finally verified the accuracy and repeatability of the formula. In conclusion, the establishment and implementation of a newly functional relationship among the PDT parameters are essential for predicting PDT outcomes and providing personalized precise treatment, and they are contributive to the development of PDT dosimetry.     

乌镇古镇滨水建筑外部空间研究

外部空间元素通过一定的组织手法有规律地形成了乌镇古镇的外部空间结构。使用建筑设计中的平面关系图和剖立面图来解析外部空间结构,从而清晰、明确体现这种外部空间结构,并总结出乌镇古镇外部空间的平面关系和剖立面关系的特点以及与西塘、南浔古镇的异同。     

废弃锂电池电极材料中有价金属的赋存状态

这是一篇冶金工程领域的论文。以废旧磷酸铁锂电池正极粉为对象,开展了以Na₂S₂O₈作为氧化剂,并添加低浓度乙酸作为浸出剂选择性浸锂的研究,考查了Na₂S₂O₈加入量、乙酸浓度、浸出温度、浸出液固比和浸出时间等对锂选择性浸出影响。在乙酸浓度0.3 mol/L、Na₂S₂O₈加入量为理论量的1.1倍,浸出液固比10 mL/g、室温浸出2 h条件下,锂、铁、磷的浸出率分别为98.05%、4.49%和2.46%。