The Redox-Sensing Regulator Rex Contributes to the Virulence and Oxidative Stress Response of Streptococcus suis Serotype 2

Streptococcus suis serotype 2 (SS2) is an important zoonotic pathogen responsible for septicemia and meningitis. The redox-sensing regulator Rex has been reported to play critical roles in the metabolism regulation, oxidative stress response, and virulence of various pathogens. In this study, we identified and characterized a Rex ortholog in the SS2 virulent strain SS2-1 that is involved in bacterial pathogenicity and stress environment susceptibility. Our data show that the Rex-knockout mutant strain Δrex exhibited impaired growth in medium with hydrogen peroxide or a low pH compared with the wildtype strain SS2-1 and the complementary strain CΔrex. In addition, Δrex showed a decreased level of survival in whole blood and in RAW264.7 macrophages. Further analyses revealed that Rex deficiency significantly attenuated bacterial virulence in an animal model. A comparative proteome analysis found that the expression levels of several proteins involved in virulence and oxidative stress were significantly different in Δrex compared with SS2-1. Electrophoretic mobility shift assays revealed that recombinant Rex specifically bound to the promoters of target genes in a manner that was modulated by NADH and NAD+. Taken together, our data suggest that Rex plays critical roles in the virulence and oxidative stress response of SS2

Inspirations From the Study on the Characteristics of the United States Marine Spatial Planning

Coastal zone planning, as a pivotal policy tool for marine management, holds significant importance in realizing sustainable development within the coastal zone. In China's territorial spatial planning system, marine spatial planning is still under exploration and practice. The United States has had an early start in marine spatial planning. Since the 1970s, it has gradually formed a marine spatial planning system consisting of the national marine spatial planning policy framework, regional marine spatial planning, and state marine spatial planning. This paper outlines the development of the marine spatial planning system in the United States, and conducts cases analysis of the Northeast Ocean Plan, the Massachusetts Ocean Management Plan and the Rhode Island Ocean Special Area Management Plan. The analysis delves into the institutional establishment, data support, and planning coordination aspects of these initiatives, offering insights into the characteristics. Furthermore, drawing on the specific context of the establishment of China's coastal zone planning system, the article presents recommendations aimed at advancing the development of the marine spatial planning system

Juvenile hormone acts through FoxO to promote <i>Cdc2</i> and <i>Orc5</i> transcription for polyploidy-dependent vitellogenesis

Vitellogenin (Vg) is prerequisite to egg production and embryonic development after oviposition in oviparous animals. In many insects, juvenile hormone (JH) promotes fat body cell polyploidization for massive Vg synthesis required for maturation of multiple oocytes, but the underlying mechanisms remain poorly understood. Using the migratory locust Locusta migratoria as a model system, we report here that JH induces the dephosphorylation of Forkhead box O transcription factor (FoxO) through a signaling cascade including leucine carboxyl methyltransferase 1 (LCMT1) and protein phosphatase 2A (PP2A). JH promotes PP2A activity via LCMT1-mediated methylation, consequently triggering FoxO dephosphorylation. Dephosphorylated FoxO binds to the upstream of two endocycle-related genes, cell-division-cycle 2 (Cdc2) and origin-recognition-complex subunit 5 (Orc5) and activates their transcription. Depletion of FoxO, Cdc2 or Orc5 results in blocked polyploidization of fat body cells, accompanied by markedly reduced Vg expression, impaired oocyte maturation and arrested ovarian development. The results suggest that JH acts via LCMT1-PP2A-FoxO to regulate Cdc2 and Orc5 expression and enhance ploidy of fat body cells in preparation for large-scale Vg synthesis required for synchronous maturation of multiple eggs.</jats:p

Multi-component solvent-free cascade reaction of 2-cyanoacetamides: regioselective synthesis of pyridin-2-ones bearing quaternary centers

A novel protocol has been constructed for the synthesis of four types of pyridin-2-ones via multicomponent solvent-free cascade reactions of 2-cyanoacetamides, various ketones, and acetone.</p

Advances in Highly Ductile Concrete Research

In recent years, high-ductility concrete (HDC) has gradually become popular in the construction industry because of its excellent ductility and crack resistance. Concrete itself is a kind of building material with poor tensile properties, and it is necessary to add a large number of steel bars to improve its tensile properties, which increases the construction cost of buildings. However, most of the research studies on high-ductility concrete are scattered. In this paper, the basic mechanical properties of high-ductility concrete and the effects of dry and wet cycles, freeze&ndash;thaw cycles, and salt erosion on the durability of high-ductility concrete are obtained by comprehensive analysis. The results show that the tensile properties of HDC can be significantly improved by adding appropriate fiber. When the volume fraction of steel fiber is 2.0%, the splitting tensile strength of concrete is increased by 98.3%. The crack width threshold of concrete chloride erosion is 55&ndash;80 &mu;m, and when the crack width threshold is exceeded, the diffusion of CL-1 will be accelerated, and the HDC can control the crack within the threshold, thereby improving the durability of the concrete. Finally, the current research status of high-ductility concrete is analyzed, and the future development of high-ductility concrete is proposed

Study on Tensile Properties and Failure Modes of BFRC

Abstract The effects of basalt fiber volume fraction and fiber length on the tensile properties of concrete are studied by experiments. The mechanism of fiber improving the tensile failure mode of concrete is analyzed. The results show that the tensile properties of BFRC are significantly improved compared with the matrix concrete. The initial crack strength and yield strength increase significantly with the increase of fiber volume fraction, while the initial crack strain and yield strain increase significantly with the increase of fiber length. The roughness coefficient of BFRC fracture surface can be used as the index of fiber improving concrete tensile properties.</jats:p