MoaE Is Involved in Response to Oxidative Stress in Deinococcus radiodurans.

Molybdenum ions are covalently bound to molybdenum pterin (MPT) to produce molybdenum cofactor (Moco), a compound essential for the catalytic activity of molybdenum enzymes, which is involved in a variety of biological functions. MoaE is the large subunit of MPT synthase and plays a key role in Moco synthesis. Here, we investigated the function of MoaE in Deinococcus radiodurans (DrMoaE) in vitro and in vivo, demonstrating that the protein contributed to the extreme resistance of D. radiodurans. The crystal structure of DrMoaE was determined by 1.9 Å resolution. DrMoaE was shown to be a dimer and the dimerization disappeared after Arg110 had been mutated. The deletion of drmoaE resulted in sensitivity to DNA damage stress and a slower growth rate in D. radiodurans. The increase in drmoaE transcript levels the and accumulation of intracellular reactive oxygen species levels under oxidative stress suggested that it was involved in the antioxidant process in D. radiodurans. In addition, treatment with the base analog 6-hydroxyaminopurine decreased survival and increased intracellular mutation rates in drmoaE deletion mutant strains. Our results reveal that MoaE plays a role in response to external stress mainly through oxidative stress resistance mechanisms in D. radiodurans.

Macrothrombocytopenia with leukocyte inclusions in a patient with Wilson disease: a case report and literature review.

BACKGROUND: Wilson disease (WD) is an autosomal recessive disorder caused by homozygous or compound heterozygous mutations in ATP7B. Clinical manifestations primarily involve liver and nervous system lesions, with rarely observed hematologic manifestations. CASE PRESENTATION: In the present case, a patient with WD presented with thrombocytopenia, giant platelets, and Döhle-like cytoplasmic inclusions in the leukocytes. Initially, the May-Hegglin anomaly was considered; however, whole-exome sequencing did not reveal any mutation in the MYH9 gene but a heterozygous mutation was found in (C.2804 C > T, p.T935M) in the ATP7B gene. After two years, the patient developed tremors in his hands, lower limb stiffness, and foreign body sensation in the eyes. Additionally, Kayser-Fleischer rings in the corneal limbus were detected by slit-lamp examination. Copper metabolism test indicated a slight decrease in serum ceruloplasmin. Transmission electron microscopy revealed that the inclusion bodies of leukocytes were swollen mitochondria. Mass spectrometry analysis showed that the copper levels were almost 20-fold higher in the leukocytes of the patient than in those of the control group. Based on the Leipzig scoring system, a diagnosis of WD was confirmed. Zinc sulfate treatment ameliorated the patient's symptoms and enhanced platelet, serum ceruloplasmin, and albumin levels. CONCLUSIONS: In conclusion, this case represents the first documented instance of WD presenting as thrombocytopenia, giant platelets, and Döhle-like cytoplasmic inclusions in the leukocytes. Excessive cellular copper accumulation likely underlies these findings; however, understanding precise mechanisms warrants further investigation.

DRJAMM Is Involved in the Oxidative Resistance in Deinococcus radiodurans.

Proteins containing JAB1/MPN/MOV34 metalloenzyme (JAMM/MPN+) domains that have Zn2+-dependent deubiquitinase (DUB) activity are ubiquitous across among all domains of life. Recently, a homolog in Deinococcus radiodurans, DRJAMM, was reported to possess the ability to cleave DRMoaD-MoaE. However, the detailed biochemical characteristics of DRJAMM in vitro and its biological mechanism in vivo remain unclear. Here, we show that DRJAMM has an efficient in vitro catalytic activity in the presence of Mn2+, Ca2+, Mg2+, and Ni2+ in addition to the well-reported Zn2+, and strong adaptability at a wide range of temperatures. Disruption of drJAMM led to elevated sensitivity in response to H2O2 in vivo compared to the wild-type R1. In particular, the expression level of MoaE, a product of DRJAMM cleavage, was also increased under H2O2 stress, indicating that DRJAMM is needed in the antioxidant process. Moreover, DRJAMM was also demonstrated to be necessary for dimethyl sulfoxide respiratory system in D. radiodurans. These data suggest that DRJAMM plays key roles in the process of oxidative resistance in D. radiodurans with multiple-choice of metal ions and temperatures.

N 4-Cytosine DNA Methylation Is Involved in the Maintenance of Genomic Stability in Deinococcus radiodurans.

DNA methylation serves as a vital component of restriction-modification (R-M) systems in bacteria, where it plays a crucial role in defense against foreign DNA. Recent studies revealed that DNA methylation has a global impact on gene expression. Deinococcus radiodurans, an ideal model organism for studying DNA repair and genomic stability, possesses unparalleled resistance to DNA-damaging agents such as irradiation and strong oxidation. However, details on the methylome of this bacterium remain unclear. Here, we demonstrate that N 4-cytosine is the major methylated form (4mC) in D. radiodurans. A novel methylated motif, "C4mCGCGG" was identified that was fully attributed to M.DraR1 methyltransferase. M.DraR1 can specifically bind and methylate the second cytosine at N 4 atom of "CCGCGG" motif, preventing its digestion by a cognate restriction endonuclease. Cells deficient in 4mC modification displayed higher spontaneous rifampin mutation frequency and enhanced DNA recombination and transformation efficiency. And genes involved in the maintenance of genomic stability were differentially expressed in conjunction with the loss of M.DraR1. This study provides evidence that N 4-cytosine DNA methylation contributes to genomic stability of D. radiodurans and lays the foundation for further research on the mechanisms of epigenetic regulation by R-M systems in bacteria.

Risk factors of severe hand, foot and mouth disease in Shantou, China: a case-control study.

INTRODUCTION: In clinical perspectives, how to distinguish a small proportion of children at risk of developing neurological complications from a large number of children with mild symptoms still remains a challenge for primary care doctors. METHODOLOGY: From January 2012 to December 2015, 225 cases with severe hand, foot and mouth disease (HFMD) matched with 492 controls were enrolled in the age-matched, case-control study. Continuous variables were examined by univariate analysis using a chi-squared or Fisher's exact test, and categorical variables were reported by relative risks (odd's ratio). Multivariate logistic regression was used to analyze the independent risk factors for severe HFMD. RESULTS: Peak body temperature over 37.5℃，total duration of fever over 3 days, lethargy, enterovirus 71 (EV71) infection were independent risk factors for severe HFMD. CONCLUSIONS: Peak body temperature over 37.5℃，total duration of fever over 3 days, lethargy, EV71 infection were independent risk factors for severe HFMD.