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Objective The Ordos block, with typical boundary zone activity, is located in the center of mainland China. Influenced by the remote action of the Tibetan Plateau in the southwest and the Pacific Plate in the east, each boundary zone of the Ordos Block exhibits distinct tectonic activity and deformation characteristics. This study aims to provide insights into the characteristics of strong earthquake generation and the future seismic risk along the boundaries of the Ordos active block. Methods This study systematically summarizes research achievements made in the study of active faults and the seismogenic mechanism of strong earthquakes around the Ordos Block over the past few decades, providing a systematic overview of the characteristics of fault activity and seismic generation mechanisms along the block' s periphery. Conslusion The differences in fault activity in each boundary zone determined the differences in the earthquake-breeding strong tectonic environments. In the southern section of the western boundary, the faults are mainly characterized by strike-slip, reverse strike-slip, and thrust owing to the influence of the northward compression and expansion of the Qinghai-Tibet Plateau, resulting in complex structural deformation styles within the boundary zone. In the northern section of the western boundary, the latest expansion boundary of the Qinghai-Tibet Plateau is characterized by dextral movement along the Sanguankou-Niushoushan fault. The Yinchuan Basin in the northern section of the western boundary zone is a typical fault basin with basin-controlling faults exhibiting dextral strike-slip characteristics, and earthquakes are primarily of the standard strike-slip type. The Hetao Basin on the northern boundary is controlled by normal faults on its northern side, with historical and ancient earthquakes concentrated on the northern boundary faults. The Weihe Basin on the southern boundary exhibits relatively complex structural features, comprising two sets of normal faults. Historical major earthquakes mostly occur at the southern edge of the basin, with moderate seismic activity in the central-northern part of the basin. The Shanxi Graben system on the eastern boundary comprises multiple rift-type basins. Historical major earthquakes exhibit a pattern of stronger activity in the south and weaker activity in the north. The northern basins are influenced by the Zhang-Bo tectonic belt, resulting in significant changes in basin trend and fault movement characteristics, often possessing the structural conditions necessary for earthquakes of around M 7.0. Overall, in the typical fault activity zones surrounding the Ordos active block, future strong earthquakes are more likely to occur in seismic gaps or transition zones of fault systems, where significant time has passed since the occurrence of major earthquakes or at the intersections of tectonic zones.

The role of prokaryotic CRISPR/Cas system proteins as a defensive shield against invasive nucleic acids has been studied extensively. Non-canonical roles in pathogenesis involving intracellular targeting of certain virulence-associated endogenous mRNA have also been reported for some Type I and Type II CRISPR/Cas proteins, but no such roles have yet been established for Type III system proteins. Here, we demonstrate that M. tuberculosis (Type III-A system) CRISPR/Cas proteins Csm1, Csm3, Csm5, Csm6, and Cas6 are secreted and induce host immune responses. Using cell and animal experiments, we show that Cas6, in particular, provokes IFN-γ release from PBMCs from active tuberculosis (TB) patients, and its deletion markedly attenuates virulence in a murine M. tuberculosis challenge model. Recombinant MTBCas6 induces apoptosis of macrophages and lung fibroblasts, and interacts with the surface of cells in a caspase and TLR-2 independent manner. Transcriptomic and signal pathway studies using THP-1 macrophages stimulated with MTBCas6 indicated that MTBCas6 upregulates expression of genes associated with the NF-κB pathway leading to higher levels of IL-6, IL-1β, and TNF-α release, cytokines known to activate immune system cells in response to M. tuberculosis infection. Our findings suggest that, in addition to their intracellular shielding role, M. tuberculosis CRISPR/Cas proteins have non-canonical extracellular roles, functioning like a virulent sword, and activating host immune responses.

Tuberculosis (TB), a disease caused by Mycobacterium tuberculosis (MTB) infection, remains a major threat to global public health. To facilitate early TB diagnosis, an IS6110 gene-based recombinase aided amplification (RAA) assay was coupled to a clustered, regularly interspaced short palindromic repeats (CRISPR)-Cas13a fluorescence assay to create a rapid MTB detection assay (named RAA-CRISPR-MTB). Its diagnostic efficacy was evaluated for sensitivity and specificity through sequential testing of recombinant plasmids, mycobacterium strains, and clinical specimens. RAA-CRISPR detected IS6110 genes at levels approaching 1 copy/μL with pUC57-6110 as the template and 10 copies/μL with H37Rv as the template. There was no observed cross detection of non-tuberculosis mycobacteria (NTM) with either template. Furthermore, RAA-CRISPR testing of 151 clinical specimens yielded a diagnostic specificity rate of 100% and a diagnostic sensitivity rate of 69% that exceeded the corresponding Xpert MTB/RIF assay rate (60%). In conclusion, we established a novel RAA-CRISPR assay that achieved highly sensitive and specific MTB detection for use as a clinical TB diagnostic tool in resource-poor settings. [ABSTRACT FROM AUTHOR]

The Ganzi–Xianshuihe Fault Zone is a large-scale sinistral strike-slip fault zone on the eastern Tibet. As the boundary fault zone of the Bayankala Block and the Chuandian Block, it controls the clockwise rotation of the southeastern Tibet. However, there is still controversy regarding the activity changes between fault zones. Therefore, accurately determining the slip rates of faults in the area is crucial for characterizing regional plate motions and assessing associated seismic hazards. We focused on studying four fault segments near the Ganzi–Xianshuihe Fault Zone, including the Manigango, Ganzi, Luhuo, and Daofu segments. In each segment, we selected typical sinistral piercing points and carried out Unmanned Aerial Vehicle (UAV) photogrammetry to obtain high-resolution terrain data. We utilized LaDiCaoz_V2.2 and GlobalMapper software (LaDiCaoz_V2.2 and Global Mapper v17.0) to measure the offsets, together with optically stimulated luminescence (OSL) dating, to constrain the timing of fault activity. The estimated slip rates for the Manigango, Ganzi, Luhuo, and Daofu segments are as follows: 9.2 ± 0.75 mm/yr, 9.59 ± 1.7 mm/yr, 4.23 ± 0.66 mm/yr, and 7.69 ± 0.76 mm/yr, respectively. Integrating previous results with slip rates estimated in this study, our analysis suggests the slip rate of the Ganzi–Xianshuihe Fault Zone is around 8–10 mm/year, exhibiting a consistent slip rate from northwest to southeast. This reflects the overall coordination of the movement on the eastern Tibet, with the strike-slip fault zone only controlling the direction of movement. [ABSTRACT FROM AUTHOR]