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An improved transition model with mechanical considerations is proposed in this paper for hypersonic boundary-layer transition. The original V-SST model is not suitable for hypersonic flow with low freestream turbulence intensity. Thus, three key modifications based on the physical mechanisms and multiple unstable modes, which involve the addition of source term in the transport equation, reconstruction of pretransitional viscosity, and reformulation of the control function of effective turbulence viscosity, are constructed to make it possible to predict the hypersonic transition process. Numerous validation test cases are chosen to adequately access the prediction accuracy of the current transition model, including flat plates and blunt cones with different Reynolds numbers, a double ramp, an inlet model with composite shock interference flow, and three-dimensional X-51A forebody model. The flow structures and heat transfer distributions predicted by the numerical simulation are well consistent with experimental data, which demonstrate the capability of improved V-SST transition model in accurately predicting hypersonic transition behavior and reasonably reflecting the influence of freestream unit Reynolds number. It needs to further investigate the performance of the current model in capturing unusual transition phenomenon such as heat transfer overshoot, and consider more physical influence factors on boundary-layer transition. [ABSTRACT FROM AUTHOR]

Assembly of the adenovirus capsid protein hexon depends on the assistance of the molecular chaperone L4-100K. However, the chaperone mechanisms remain unclear. In this study, we found that L4-100K was involved in the hexon translation process and could prevent hexon degradation by the proteasome in cotransfected human cells. Two nonadjacent domains, 84-133 and 656-697, at the N-terminal and C-terminal regions of human adenovirus type 5 L4-100K, respectively, were found to be crucial and cooperatively responsible for hexon trimer expression and assembly. These two chaperone-related domains were conserved in the sequence of L4-100K and in the function of hexon assembly across different adenovirus serotypes. Different degrees of cross-activity of hexon trimerization with different serotypes were detected in subgroups B, C, and D, which were proven to be controlled by the interaction between the C-terminal chaperone-related domain of L4-100K and hypervariable regions (HVR) of hexon. Additionally, HVR-chimeric hexon mutants were successfully assembled with the assistance of the 1- 697 mutant. Structural analysis of 656-697 by nuclear magnetic resonance and structural prediction of L4-100K using Robetta showed that the two conserved domains are mainly composed of a-helices and are located on the surface of the highly folded core region. Our research provides a more complete understanding of hexon assembly and guidance for the development of hexon-chimeric adenovirus vectors that will be safer, smarter, and more efficient. IMPORTANCE Adenovirus vectors have been widely used in clinical trials of vaccines and gene therapy, although some deficiencies remain. Chimeric modification of the hexon was expected to improve the potency of preexisting immune evasion and targeting, but in many cases, viral packaging is prevented by the inability of the chimeric hexon to assemble correctly. So far, few studies have examined the mechanisms of hexon trimer assembly. Here, we show how the chaperone protein L4-100K contributes to the assembly of the adenovirus capsid protein hexon, and these data will provide a guide for novel adenovirus vector design and development, as we desired. [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass is widely used in the field of laccase production because it has the advantages of low price and easy availability. Thus, a comparative analysis was performed of the laccase secretion ability of five white-rot fungi in submerged fermentation using single or mixtures of lignocellulosic biomass. Maximum laccase activity of Trametes gibbosa An 360, Vanderbylia fraxinea An 369, Perenniporia pyricola Han 202, Coriolopsis trogii Han 474, and Trametes versicolor Han 1504 was 55.83 ± 0.28 U/L on the mixture of corncob and cottonseed hull, 77.96 ± 1.60 U/L on corncob, 443.33 ± 15.49 U/L on corncob, 686.57 ± 16.49 U/L on corncob, and 162.04 ± 11.33 U/L on cottonseed hull. The mixed lignocellulosic material effectively improved the laccase activity of T. gibbosa An 360 compared with other fungal strains. However, the presence of corncob contributed to the secretion of laccase activity for V. fraxinea An 369, P. pyricola Han 202, and C. trogii Han 474. Meanwhile, cottonseed hull was conducive to the secretion of laccase of T. versicolor Han 1504. Laccase activity of P. pyricola Han 202 was very stable throughout most of the fermentation time. The results from this study provide new methods and increase fungal strains to improve laccase activity. [ABSTRACT FROM AUTHOR]

Laccase activity secreted by Pleurotus eryngii Han 1787 and Lentinus edodes Han 1788 grown on six types of agroindustrial wastes was investigated. Maximum laccase activity of P. eryngii Han 1787 on Ulmus pumila, Juniperus formosana, Pinus tabuliformis, cottonseed shell, corncob, and leaf of corncob was nearly 5.77-fold, 2.37-fold, 2.78-fold, 2.81-fold, 11.53-fold, and 6.73-fold higher than that of L. edodes Han1788 on corresponding agroindustrial wastes. In general, the capacity of secreting laccase of P. eryngii Han 1787 was superior to that of L. edodes Han 1788. Furthermore, laccase activity of P. eryngii Han 1787 on the leaf of corncob, the corncob, Ulmus pumila, and Juniperus formosana was relatively stable during the whole fermentation process. Different fungi showed different preferences in different agroindustrial wastes to secret laccase on whole fermentation stage. The presence of leaf of corncob was useful for improving laccase activity of P. eryngii Han 1787, while L. edodes Han 1788 was more preferred to produce laccase along with the presence of Juniperus formosana. These results were preliminary conducive in laying the foundation for increasing industrial laccaseproducing strains and producing low-cost laccase. [ABSTRACT FROM AUTHOR]

The laccase activity of three cultivated Pleurotus strains was investigated using different lignocellulosic biomasses for solid-state fermentation. The lignocellulosic biomasses were Sophora japonica, Salix babylonica, Populus beijingensis, and Pinus tabuliformis, which were selected because of their laccase producing ability and low cost. The maximum laccase activities from P. ostreatus Han 1189, P. citrinopileatus Han 1192, and P. eryngii Han 1205 using Sophora japonica were 768.74 U/L ± 11.25 U/L, 144.77 U/L ± 9.70 U/L, and 200.42 U/L ± 6.85 U/L, respectively. The three species of Pleurotus showed consistency in having a preference of hardwood to secret laccase under solid-state fermentation when facing hardwood and softwood as substrates. Furthermore, the presence of Sophora japonica was beneficial to improving the laccase activity for three Pleurotus strains. The capacity of the laccase secretion of P. ostreatus Han 1189 was superior to the capacity of P. citrinopileatus Han 1192 and P. eryngii Han 1205. The discovery was helpful for obtaining new highproducing strains and suitable wood materials, as well as expanding these high-producing strains for industrial applications to obtain high laccase activity, high laccase yield, and low cost laccase. [ABSTRACT FROM AUTHOR]

Laccase has huge potential application in all aspects of biotechnology due to the ability of laccase to oxidize a wide range of phenolic and nonphenolic compounds. The future success of such applications requires large amounts of laccase with low costs. White-rot fungi are important groups of laccase production. In this study, three white-rot fungi, Phlebia acerina Han 618, Trametes hirsuta Han 726, and Coriolopsis trogii Han 751, isolated from a native North China habitat, were identified by the method of molecular biology and preliminary screening of the ability of laccase-production by guaiacol selection medium. Then they were fermented on different lignocellulosic biomass. Three species showed consistency in preference of lignocellulosic biomass, and the presence of stalk of Sorghum bicolor was more suitable for secreting laccase. The capacity of laccase secretion from different species was significantly different. The capacity of secreting laccase of C. trogii Han 751 was superior to that of P. acerina Han 618 and T. hirsuta Han 726. The discovery of a new strain with superior capacity of secreting laccase and suitable lignocellulosic biomass were helpful for laying a foundation for the optimization of the fermentation conditions for the highest laccase production, the isolation and purification of laccase, and the industrial application of laccase. [ABSTRACT FROM AUTHOR]