Insight to Pyroptosis in Viral Infectious Diseases

Background: Pyroptosis is defined as programmed necrosis executed by gasdermin D or E (GSDMD or GSDME), which punches cellular membrane. Morphologically, pyroptosis is characterized by cell swelling and cell membrane rupture, leading to the release of cellular contents that triggers intense inflammatory response. More and more studies have found that pyroptosis may be involved in the pathogenesis of viral infection, which may be a determinant for inflammation observed in most viral diseases. Objective: This paper aims to summarize the roles of pyroptosis in the pathogenesis of viral infectious diseases and to provide potential drug targets for the treatment of viral diseases, which will contribute to medical research and public health. Measures: This paper mainly summarizes pyroptosis occurring in diseases caused by different viruses, including human immunodeficiency virus, hepatitis virus, enterovirus, influenza virus and dengue fever virus. Meanwhile, the reported mechanism underlying pyroptosis mediating pathogenesis of these viral diseases will also be described. Conclusion: Current studies have shown that pyroptosis is a double-edged sword in viral infectious diseases. On one hand, pyroptosis leads to pathogenic inflammation of many viral infectious diseases which aggravate tissue damage initiated by viral infection, and blocking proptosis usually relieves the inflammation, which exerts therapeutic effects on viral diseases. On the other hand, moderating pyroptosis can contribute to defense against pathogen infection by releasing immune epitopes and inducing antiviral immune response.

Identification and Functional Analysis of Three MAX2 Orthologs in Chrysanthemum

MORE AXILLARY BRANCHING 2 （MAX2）, initially identified in Arabidopsis thaliana, is a key regulatory gene in strigolactone signal transduction. Three orthologs of MAX2 were cloned from Dendranthema grandiflorum （DgMAX2a, b, and c）. Each of the genes has an open reading frame of 2,049 bp and encodes 682 amino acid proteins. The predicted amino acid sequences of the three DgMAX2s are most closely related to the MAX2 orthologs identified in petunia （PhMAX2A and PhMAX2B）, and display the highest amino acid sequence similarity with PhMAX2A compared to other MAX2s. Expression analysis revealed that DgMAX2s are predominantly expressed in the stem and axillary buds. On a cellular level, we localized the DgMAX2a：：GFP fusion protein to the nucleus in onion epidermal cells, which is consistent with the nuclear localization of MAX2 in Arabidopsis. The chrysanthemum DgMAX2a is able to restore the max2–1 mutant branching to wild-type （WT） Arabidopsis, suggesting that it is a functional MAX2 ortholog. These results suggest that DgMAX2s may be candidate genes for reducing the shoot branching of chrysanthemum.

Optimization method for solving bang-bang and singular control problems

In this paper we study optimal control problems with the control variable appearing linearly. A novel method for optimization with respect to the switching times of controls containing both bang-bang and singular arcs is presented. This method transforms the control problem into a finite-dimensional optimization problem by reformulating the control problem as a multi-stage optimization problem. The optimal control problem is partitioned as several stages, with each stage corresponding to a particular control arc. A control vector parameterization approach is applied to convert the control problem to a static nonlinear programming （NLP） problem. The control profiles and stage lengths act as decision variables. Based on the Pontryagin maximal principle, a multi-stage adjoint system is constructed to calculate the gradients required by the NLP solvers. Two examples are studied to demonstrate the effectiveness of this strategy.