Differing Requirements for RAD51 and DMC1 in Meiotic Pairing of Centromeres and Chromosome Arms in Arabidopsis thaliana

During meiosis homologous chromosomes pair, recombine, and synapse, thus ensuring accurate chromosome segregation and the halving of ploidy necessary for gametogenesis. The processes permitting a chromosome to pair only with its homologue are not fully understood, but successful pairing of homologous chromosomes is tightly linked to recombination. In Arabidopsis thaliana, meiotic prophase of rad51, xrcc3, and rad51C mutants appears normal up to the zygotene/pachytene stage, after which the genome fragments, leading to sterility. To better understand the relationship between recombination and chromosome pairing, we have analysed meiotic chromosome pairing in these and in dmc1 mutant lines. Our data show a differing requirement for these proteins in pairing of centromeric regions and chromosome arms. No homologous pairing of mid-arm or distal regions was observed in rad51, xrcc3, and rad51C mutants. However, homologous centromeres do pair in these mutants and we show that this does depend upon recombination, principally on DMC1. This centromere pairing extends well beyond the heterochromatic centromere region and, surprisingly, does not require XRCC3 and RAD51C. In addition to clarifying and bringing the roles of centromeres in meiotic synapsis to the fore, this analysis thus separates the roles in meiotic synapsis of DMC1 and RAD51 and the meiotic RAD51 paralogs, XRCC3 and RAD51C, with respect to different chromosome domains

Global, regional, and national incidence of six major immune-mediated inflammatory diseases: findings from the global burden of disease study 2019

Background The causes for immune-mediated inflammatory diseases (IMIDs) are diverse and the incidence trends of IMIDs from specific causes are rarely studied. The study aims to investigate the pattern and trend of IMIDs from 1990 to 2019. Methods We collected detailed information on six major causes of IMIDs, including asthma, inflammatory bowel disease, multiple sclerosis, rheumatoid arthritis, psoriasis, and atopic dermatitis, between 1990 and 2019, derived from the Global Burden of Disease study in 2019. The average annual percent change (AAPC) in number of incidents and age standardized incidence rate (ASR) on IMIDs, by sex, age, region, and causes, were calculated to quantify the temporal trends. Findings In 2019, rheumatoid arthritis, atopic dermatitis, asthma, multiple sclerosis, psoriasis, inflammatory bowel disease accounted 1.59%, 36.17%, 54.71%, 0.09%, 6.84%, 0.60% of overall new IMIDs cases, respectively. The ASR of IMIDs showed substantial regional and global variation with the highest in High SDI region, High-income North America, and United States of America. Throughout human lifespan, the age distribution of incident cases from six IMIDs was quite different. Globally, incident cases of IMIDs increased with an AAPC of 0.68 and the ASR decreased with an AAPC of −0.34 from 1990 to 2019. The incident cases increased across six IMIDs, the ASR of rheumatoid arthritis increased (0.21, 95% CI 0.18, 0.25), while the ASR of asthma (AAPC = −0.41), inflammatory bowel disease (AAPC = −0.72), multiple sclerosis (AAPC = −0.26), psoriasis (AAPC = −0.77), and atopic dermatitis (AAPC = −0.15) decreased. The ASR of overall and six individual IMID increased with SDI at regional and global level. Countries with higher ASR in 1990 experienced a more rapid decrease in ASR. Interpretation The incidence patterns of IMIDs varied considerably across the world. Innovative prevention and integrative management strategy are urgently needed to mitigate the increasing ASR of rheumatoid arthritis and upsurging new cases of other five IMIDs, respectively. Funding The Global Burden of Disease Study is funded by the Bill and Melinda Gates Foundation. The project funded by Scientific Research Fund of Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital (2022QN38)

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Not AvailableSoil hydraulic conductivity depends on the composition of exchangeable cations and the composition and concentration of the electrolytes in the soil solution as well as soil texture. This laboratory experiment was conducted on salt affected soils viz P1 (Samni village-Typic Haplustert), P2 (Kalamsar village-Fluventic Haplustept), P3 (Traj village-Typic Halaquept), P4 (Saragwada village-Typic Ustorthent) and P5 (Kharad village- Vertic Haplustept) to determine the hydro-physical behaviour under different water qualities and physico-chemical parameters of the soil. Concentration and composition of the water flowing through the soil showed a marked influence on saturated hydraulic conductivity of salt affected soils. Soil pH ranged from 7.5 to 8.4 and ECe from 2.8 to 132 dS m-1. Result revealed that hydraulic conductivity increased with increasing ECe of the soil in both SAR (10 and 20 m mol1/2 L-1/2) with different TEC (10, 20, 40, 80 and 100 me L-1). The maximum Ks was observed in sandy clay loam soil with high ECe i.e. 0.213 cm h-1 in SAR 10 m mol1/2 L-1/2 with TEC 20 me L-1 and 0.152 cm h-1 in SAR 20 m mol1/2 L-1/2 with TEC 40 me L-1 as compare to clay and clay loam soils. The hydraulic conductivity decreased with increase in the ESP and decrease in the total electrolytic concentration of the soil solution, whereas this trend was not observed in clay loam soils (P2 and P3), which showed low ESP and ECe with result of least value of Ks. In clay loam soils, presence of CO3-- and HCO3- was observed very high as compared to clay and sandy clay loam soils which might be a major cause of low Ks values. Among all the cations and anions Na+, and Cl- were dominant in all the soils. The reduction in the hydraulic conductivity may be attributed to swelling and dispersion of the soil clays. Thus the study indicated that the combined effect of water quality and soil properties on saturated hydraulic conductivity (Ks) was influenced by SAR and TEC with ECe, ESP as well as the cations and anions of the soils.ICA