An Orthogonal T7 Replisome for Continuous Hypermutation and Accelerated Evolution in .

Systems that perform continuous hypermutation of designated genes without compromising the integrity of the host genome can dramatically accelerate the evolution of new or enhanced protein functions. We describe an orthogonal DNA replication system in based on the controlled expression of the replisome of bacteriophage T7. The system replicates circular plasmids that enable high transformation efficiencies and seamless integration into standard molecular biology workflows.

A parameterized two-domain thermodynamic model explains diverse mutational effects on protein allostery.

New experimental findings continue to challenge our understanding of protein allostery. Recent deep mutational scanning study showed that allosteric hotspots in the tetracycline repressor (TetR) and its homologous transcriptional factors are broadly distributed rather than spanning well-defined structural pathways as often assumed. Moreover, hotspot mutation-induced allostery loss was rescued by distributed additional mutations in a degenerate fashion.

A parametrized two-domain thermodynamic model explains diverse mutational effects on protein allostery.

New experimental findings continue to challenge our understanding of protein allostery. Recent deep mutational scanning study showed that allosteric hotspots in the tetracycline repressor (TetR) and its homologous transcriptional factors are broadly distributed rather than spanning well-defined structural pathways as often assumed. Moreover, hotspot mutation-induced allostery loss was rescued by distributed additional mutations in a degenerate fashion.

Effects of the 5'-Triphosphate Metabolites of Ribavirin, Sofosbuvir, Vidarabine, and Molnupiravir on CTP Synthase Catalysis and Filament Formation: Implications for Repurposing Antiviral Agents against SARS-CoV-2.

Repurposing of antiviral drugs affords a rapid and effective strategy to develop therapies to counter pandemics such as COVID-19. SARS-CoV-2 replication is closely linked to the metabolism of cytosine-containing nucleotides, especially cytidine-5'-triphosphate (CTP), such that the integrity of the viral genome is highly sensitive to intracellular CTP levels. CTP synthase (CTPS) catalyzes the rate-limiting step for the de novo biosynthesis of CTP.

Molecular investigation of the tandem Tudor domain and plant homeodomain histone binding domains of the epigenetic regulator UHRF2.

Ubiquitin-like containing PHD and ring finger (UHRF)1 and UHRF2 are multidomain epigenetic proteins that play a critical role in bridging crosstalk between histone modifications and DNA methylation. Both proteins contain two histone reader domains, called tandem Tudor domain (TTD) and plant homeodomain (PHD), which read the modification status on histone H3 to regulate DNA methylation and gene expression. To shed light on the mechanism of histone binding by UHRF2, we have undergone a detailed molecular investigation with the TTD, PHD and TTD-PHD domains and compared the binding activity to its UHRF1 counterpart.

Erratum: Author Correction: LepVax, a defined subunit vaccine that provides effective pre-exposure and post-exposure prophylaxis of infection.

[This corrects the article DOI: 10.1038/s41541-018-0050-z.].

LepVax, a defined subunit vaccine that provides effective pre-exposure and post-exposure prophylaxis of infection.

Sustained elimination of leprosy as a global health concern likely requires a vaccine. The current standard, BCG, confers only partial protection and precipitates paucibacillary (PB) disease in some instances. When injected into mice with the T helper 1 (Th1)-biasing adjuvant formulation Glucopyranosyl Lipid Adjuvant in stable emulsion (GLA-SE), a cocktail of three prioritized antigens (ML2055, ML2380 and ML2028) reduced infection levels.

Nitazoxanide is active against Mycobacterium leprae.

Nitazoxanide (NTZ) is an anti-parasitic drug that also has activity against bacteria, including Mycobacterium tuberculosis. Our data using both radiorespirometry and live-dead staining in vitro demonstrate that NTZ similarly has bactericidal against M. leprae.

Current knowledge on Mycobacterium leprae transmission: a systematic literature review.

Unlabelled: Summary

Background: The transmission pathways of Mycobacterium leprae are not fully understood. Solid evidence exists for an increased risk for individuals living in close contact with leprosy patients but the existence of zoonotic leprosy, environmental reservoirs and trauma-related transmission has also been established.

Purpose: To assess the current state of knowledge on M.

Regulation of HBV-specific CD8(+) T cell-mediated inflammation is diversified in different clinical presentations of HBV infection.

Chronic HBV infection is the leading cause of liver cirrhosis and hepatic cancer, but the individual responses toward HBV infection are highly variable, ranging from asymptomatic to chronic active hepatitis B inflammation. In this study, we hypothesized that the different individual responses to HBV infection was associated with differences in HBV-specific CD8(+) T cell-mediated inflammation and cytotoxicity. Blood samples were collected from subjects with asymptomatic HBV-infection, subjects undergoing active chronic HBV flares (active CHB), and subjects with HBV-infected hepatocellular carcinoma (HBV-HCC).

rBCG30-induced immunity and cross-protection against Mycobacterium leprae challenge are enhanced by boosting with the Mycobacterium tuberculosis 30-kilodalton antigen 85B.

Leprosy remains a major global health problem and typically occurs in regions in which tuberculosis is endemic. Vaccines are needed that protect against both infections and do so better than the suboptimal Mycobacterium bovis BCG vaccine. Here, we evaluated rBCG30, a vaccine previously demonstrated to induce protection superior to that of BCG against Mycobacterium tuberculosis and Mycobacterium bovis challenge in animal models, for efficacy against Mycobacterium leprae challenge in a murine model of leprosy.

Molecular assays for determining Mycobacterium leprae viability in tissues of experimentally infected mice.

Background: The inability of Mycobacterium leprae to grow on axenic media has necessitated specialized techniques in order to determine viability of this organism. The purpose of this study was to develop a simple and sensitive molecular assay for determining M. leprae viability directly from infected tissues.

Drug resistance in patients with leprosy in the United States.

Molecular drug susceptibility testing was performed on 39 US patients with leprosy. Of these, 2 had dapsone-resistant Mycobacterium leprae and 1 of these patients also had rifampin-resistant M. leprae.

What is the evidence that the putative Mycobacterium lepromatosis species causes diffuse lepromatous leprosy?

Han et al. have made a retrospective isolation of DNA from two patients with fatal Lucio's phenomenon. This DNA does have some molecular differences to M.

Advances and hurdles on the way toward a leprosy vaccine.

Prevalence rates for leprosy have declined sharply over the past 20 y, with this decline generally attributed to the WHO multi-drug therapy (MDT) campaign to provide free-of-charge treatment to all diagnosed leprosy patients. The success of this program appears to have reached its nadir, however, as evidenced by the stalled decreases in both global prevalence and new case detection rates of leprosy. Mass BCG vaccination for the prevention of tuberculosis (TB) at national levels has had a positive effect on leprosy decline and is often overlooked as an important factor in current leprosy control programs.

Probable zoonotic leprosy in the southern United States.

Background: In the southern region of the United States, such as in Louisiana and Texas, there are autochthonous cases of leprosy among native-born Americans with no history of foreign exposure. In the same region, as well as in Mexico, wild armadillos are infected with Mycobacterium leprae.

Methods: Whole-genome resequencing of M.

Hansen's disease (leprosy) complicated by secondary mycobacterial infection.

A patient with Hansen's disease received corticosteroids for a type 1 leprosy reaction and subsequently developed a new cutaneous lesion at the original biopsy site from which Mycobacterium fortuitum was cultured. A review of the literature found only two other cases of coinfection with atypical mycobacteria and Mycobacterium leprae, although there are many reports of pulmonary tuberculosis in patients with leprosy. This case highlights the diagnostic difficulties encountered when a patient has two different mycobacterial infections of the skin.

Characterisation of short tandem repeats for genotyping Mycobacterium leprae.

Objective: Establish a typing system for Mycobacterium leprae based on polymorphic DNA structures known as short tandem repeats (STR).

Design: Assess 16 polymorphic STR for sensitivity, specificity and reproducibility in standard assays using reference strains of M. leprae.

Vaccination with the ML0276 antigen reduces local inflammation but not bacterial burden during experimental Mycobacterium leprae infection.

Leprosy elimination has been a goal of the WHO for the past 15 years. Widespread BCG vaccination and multidrug therapy have dramatically reduced worldwide leprosy prevalence, but new case detection rates have remained relatively constant. These data suggest that additional control strategies, such as a subunit vaccine, are required to block transmission and to improve leprosy control.

Implications of high level pseudogene transcription in Mycobacterium leprae.

Background: The Mycobacterium leprae genome has less than 50% coding capacity and 1,133 pseudogenes. Preliminary evidence suggests that some pseudogenes are expressed. Therefore, defining pseudogene transcriptional and translational potentials of this genome should increase our understanding of their impact on M.

Enumeration of Mycobacterium leprae using real-time PCR.

Mycobacterium leprae is not cultivable in axenic media, and direct microscopic enumeration of the bacilli is complex, labor intensive, and suffers from limited sensitivity and specificity. We have developed a real-time PCR assay for quantifying M. leprae DNA in biological samples.

Transmission of leprosy: a study of skin and nasal secretions of household contacts of leprosy patients using PCR.

It is generally held that dissemination of Mycobacterium leprae is from nasal mucosa and not through the skin of infected patients. In this study, we evaluated M. leprae in the unbroken skin and nasal secretions of multibacillary (MB) leprosy patients and their contacts.