Plantlet Regeneration from Leaf Protoplast cultures of Japanese Butterbur

Protoplasts were isolated by enzyme digestion from leaf of Japanese butterbur (Petasites japonicus). The enzyme incubation mixture consisted of 4% (W/V)cellulase RS, 2% (W/V) hemicellulase, 1% (W/V) pectinase-dissolved Y-23 and polygalacturonase in a solution of 0. 5 mol/L mannitol at pH 5.7 . In the basic medium of 1/4 MS inorganic salts and 1/2 MS vitamins supplemented with 2 mg/L NAA, 0. 2–0. 5 mg/L BA, 0. 5 mol/L mannitol and 10 g/L sucrose, the cells divided luxuriantly. Regenerated plantlets were formed from callus after bud induction and root initiation.     

Studies on the Chemical Constituents of the Spores from Ganoderma lucidum Leyss et Fr,Karst

Two and ten compounds were isplated from the water portion and the ethereal soluble lipophilic fraction of Ganoderma lucidum respectively. On the basis of their chemical properties and co-TLC and IR spectral analysis, the two compounds from the water portion were identified as choline (Ⅰ) and betains (Ⅱ), ten compounds from thereal soluble fraction as tetra- cosanoic acid, stearic acid, palmitic acid, ergosta-7, 22-diene-3β-ol, nonadecanoic acid, benenic acid, tetracosane, hentriacontane, ergosterol and β-sitosterol. In addition, there are two compounds not be purified as contaminated by a small amount of ergosta-7, 22-diene-3β-ol.     

Testing the nonrandomness of chromosomal breakpoints using highest observed breakages

To determine whether a chromosomal band is a fragile site rather than a spontaneous breakpoint, an essential step is to test the nonrandomness of breakage at the region. In this paper, the nonapplicability of the testing procedure introduced by Bohm et al. is discussed, and a new detection procedure is proposed. This new procedure considers the relations of one site with the others, and can be applied to tests of the nonrandomness of breakpoints under either the proportional probability model, or the equiprobability model. A data set for Chinese patients with colorectal carcinoma is analyzed as an illustration of the proposed method. Received: 27 August 1998 / Accepted: 18 December 1998     

Universal Strategy with Structural and Chemical Crosslinking Interface for Efficient and Stable Perovskite Solar Cells

Due to the limited interface contact and weak interfacial interaction, planar heterojunction perovskite solar cells (PSCs) have space for further improvement. Herein, a structural and chemical crosslinking interface is proposed and constructed by introducing an extra layer, which blends tin dioxide (SnO₂) nanoparticles with chloride salts. Since the incorporated materials can be dissolved during the fabrication of perovskite, the quality of perovskite films is improved, leading to larger grain size and reduced trap-state density. Also, more chloride ions at the SnO₂/perovskite interface are observed and the interaction between Cl⁻ and Sn⁴⁺ is confirmed. It results in more pronounced n-type SnO₂ with better conductivity and deeper conduction bands, leading to preferable energy level alignment between SnO₂ and perovskite. Consequently, the open-circuit voltage and fill factor of the devices increase, and target cells present better stability, retaining 98% of initial efficiencies after >10 000 h storage in dry air (≈5% relative humidity) and maintaining 85.50% of the initial efficiency after 1000 h of operation under light. This strategy enables the achievement of 25.28% efficiency with a low bandgap (1.53 eV) perovskite composition, and it is confirmed to be universal when other related materials are utilized.     

Nucleated red blood cells participate in myocardial regeneration in the toad Bufo Gargarizan Gargarizan

Heart regeneration is negligible in humans and mammals but remarkable in some ectotherms. Humans and mammals lack nucleated red blood cells (NRBCs), while ectotherms have sufficient NRBCs. This study used Bufo gargarizan gargarizan, a Chinese toad subspecies, as a model animal to verify our hypothesis that NRBCs participate in myocardial regeneration. NRBC infiltration into myocardium was seen in the healthy toad hearts. Heart needle-injury was used as an enlarged model of physiological cardiomyocyte loss. It recovered quickly and scarlessly. NRBC infiltration increased during the recovery. Transwell assay was done to in vitro explore effects of myocardial injury on NRBCs. In the transwell system, NRBCs could infiltrate into cardiac pieces and could transdifferentiate toward cardiomyocytes. Heart apex cautery caused approximately 5% of the ventricle to be injured to varying degrees. In the mildly to moderately injured regions, NRBC infiltration increased and myocardial regeneration started soon after the inflammatory response; the severely damaged region underwent inflammation, scarring, and vascularity before NRBC infiltration and myocardial regeneration, and recovered scarlessly in four months. NRBCs were seen in the newly formed myocardium. Enzyme-linked immunosorbent assay and Western blotting showed that the levels of tumor necrosis factor-α, interleukin- 1β, 6, and11, cardiotrophin-1, vascular endothelial growth factor, erythropoietin, matrix metalloproteinase- 2 and 9 in the serum and/or cardiac tissues fluctuated in different patterns during the cardiac injury-regeneration. Cardiotrophin-1 could induce toad NRBC transdifferentiation toward cardiomyocytes in vitro. Taken together, the results suggest that the NRBC is a cell source for cardiomyocyte renewal/regeneration in the toad; cardiomyocyte loss triggers a series of biological processes, facilitating NRBC infiltration and transition to cardiomyocytes. This finding may guide a new direction for improving human myocardial regeneration.     

Triple mutated antibody scFv2F3 with high GPx activity: insights from MD, docking, MDFE, and MM-PBSA simulation

By combining computational design and site-directed mutagenesis, we have engineered a new catalytic ability into the antibody scFv2F3 by installing a catalytic triad (Trp²⁹–Sec⁵²–Gln⁷²). The resulting abzyme, Se-scFv2F3, exhibits a high glutathione peroxidase (GPx) activity, approaching the native enzyme activity. Activity assays and a systematic computational study were performed to investigate the effect of successive replacement of residues at positions 29, 52, and 72. The results revealed that an active site Ser⁵²/Sec substitution is critical for the GPx activity of Se-scFv2F3. In addition, Phe²⁹/Trp–Val⁷²/Gln mutations enhance the reaction rate via functional cooperation with Sec⁵². Molecular dynamics simulations showed that the designed catalytic triad is very stable and the conformational flexibility caused by Tyr¹⁰¹ occurs mainly in the loop of complementarity determining region 3. The docking studies illustrated the importance of this loop that favors the conformational shift of Tyr⁵⁴, Asn⁵⁵, and Gly⁵⁶ to stabilize substrate binding. Molecular dynamics free energy and molecular mechanics-Poisson Boltzmann surface area calculations estimated the pK _a shifts of the catalytic residue and the binding free energies of docked complexes, suggesting that dipole–dipole interactions among Trp²⁹–Sec⁵²–Gln⁷² lead to the change of free energy that promotes the residual catalytic activity and the substrate-binding capacity. The calculated results agree well with the experimental data, which should help to clarify why Se-scFv2F3 exhibits high catalytic efficiency.     

纤维堆囊菌的多细胞形态发生过程

粘细菌是具有复杂多细胞行为的革蓝氏阴性细菌,纤维堆囊菌是粘细菌中唯一能够降解纤维素的粘细菌种属。本文通过扫描电子显微镜和相差光学显微镜,分析了纤维堆囊菌在纤维素基质上的生长和子实体形态发生的多细胞行为特征,给出了生长和子实体发育的模式图谱。     

Hematopoietic but Not Endothelial Cell MyD88 Contributes to Host Defense during Gram-negative Pneumonia Derived Sepsis

Klebsiella pneumoniae is an important cause of sepsis. The common Toll-like receptor adapter myeloid differentiation primary response gene (MyD)88 is crucial for host defense against Klebsiella. Here we investigated the role of MyD88 in myeloid and endothelial cells during Klebsiella pneumosepsis. Mice deficient for MyD88 in myeloid (LysM-Myd88^−/−) and myeloid plus endothelial (Tie2-Myd88^−/−) cells showed enhanced lethality and bacterial growth. Tie2-Myd88^−/− mice reconstituted with control bone marrow, representing mice with a selective MyD88 deficiency in endothelial cells, showed an unremarkable antibacterial defense. Myeloid or endothelial cell MyD88 deficiency did not impact on lung pathology or distant organ injury during late stage sepsis, while LysM-Myd88^−/− mice demonstrated a strongly attenuated inflammatory response in the airways early after infection. These data suggest that myeloid but not endothelial MyD88 is important for host defense during gram-negative pneumonia derived sepsis.