The transformations of thiols and their dimers in the redox-mediated thiol-disulfide exchange reaction

A search for new approaches to sulfurous waste utilization is one of the urgent tasks of chemical technology. Thiol-disulfide exchange reaction (TDE) is one of the possible ways to involve technogenic wastes in organic synthesis. Electricity can promote such type of interactions. In this paper, we have studied TDE reactions involving low molecular weight thiols or their dimers under electrochemical conditions. The exchange processes were examined using the model reaction between 1-propanethiol and phenyl disulfide. Electrolysis was performed in the presence of redox mediators such as arylphosphines, substituted amines, o-, p-aminophenols or catechol. These compounds can initiate a TDE process with a formation of unsymmetrical disulfides. 4-Amino-2,6-diphenylphenol was chosen as the most effective redox mediator, which reduces the anodic overvoltage of a thiol oxidation by 1.20 V. The advantage of electrolysis in an undivided cell is the increased yield of target unsymmetrical disulfides due to the possibility of reduction ofhomodimers at the cathode. The involvement of refining waste, such as C3–C4 disulfide oil, in the reaction with substituted thiophenols made it possible to obtain a number of unsymmetrical arylalkyl disulfides with biologically active fragments in a high yield (up to 97%) under indirect electrolysis conditions

The Biological and Clinical Aspects of a Latent Tuberculosis Infection

Tuberculosis (TB), caused by bacilli from the Mycobacterium tuberculosis complex, remains a serious global public health problem, representing one of the main causes of death from infectious diseases. About one quarter of the world’s population is infected with Mtb and has a latent TB infection (LTBI). According to the World Health Organization (WHO), an LTBI is characterized by a lasting immune response to Mtb antigens without any TB symptoms. Current LTBI diagnoses and treatments are based on this simplified definition, although an LTBI involves a broad range of conditions, including when Mtb remains in the body in a persistent form and the immune response cannot be detected. The study of LTBIs has progressed in recent years; however, many biological and medical aspects of an LTBI are still under discussion. This review focuses on an LTBI as a broad spectrum of states, both of the human body, and of Mtb cells. The problems of phenotypic insusceptibility, diagnoses, chemoprophylaxis, and the necessity of treatment are discussed. We emphasize the complexity of an LTBI diagnosis and its treatment due to its ambiguous nature. We consider alternative ways of differentiating an LTBI from active TB, as well as predicting TB reactivation based on using mycobacterial “latency antigens” for interferon gamma release assay (IGRA) tests and the transcriptomic analysis of human blood cells

Synthesis and Antioxidant Activity of New Catechol Thioethers with the Methylene Linker

Novel catechol thio-ethers with different heterocyclic substituents at sulfur atom were prepared by reacting 3,5-di-tert-butyl-6-methoxymethylcatechol with functionalized thiols under acidic conditions. A common feature of compounds is a methylene bridge between the catechol ring and thioether group. Two catechols with the thio-ether group, bound directly to the catechol ring, were also considered to assess the effect of the methylene linker on the antioxidant properties. The crystal structures of thio-ethers with benzo-thiazole moieties were established by single-crystal X-ray analysis. The radical scavenging and antioxidant activities were determined using 2,2′-diphenyl-1-picrylhydrazyl radical test, ABTS∙+, CUPRAC (TEAC) assays, the reaction with superoxide radical anion generated by xanthine oxidase (NBT assay), the oxidative damage of the DNA, and the process of lipid peroxidation of rat liver (Wistar) homogenates in vitro. Most catechol-thioethers exhibit the antioxidant effect, which varies from mild to moderate depending on the model system. The dual anti/prooxidant activity characterizes compounds with adamantyl or thio-phenol substituent at the sulfur atom. Catechol thio-ethers containing heterocyclic groups (thiazole, thiazoline, benzo-thiazole, benzo-xazole) can be considered effective antioxidants with cytoprotective properties. These compounds can protect molecules of DNA and lipids from the different radical species

Genetic Passive Immunization with Adenoviral Vector Expressing Chimeric Nanobody-Fc Molecules as Therapy for Genital Infection Caused by Mycoplasma hominis.

Developing pathogen-specific recombinant antibody fragments (especially nanobodies) is a very promising strategy for the treatment of infectious disease. Nanobodies have great potential for gene therapy application due to their single-gene nature. Historically, Mycoplasma hominis has not been considered pathogenic bacteria due to the lack of acute infection and partially due to multiple studies demonstrating high frequency of isolation of M. hominis samples from asymptomatic patients. However, recent studies on the role of latent M. hominis infection in oncologic transformation, especially prostate cancer, and reports that M. hominis infects Trichomonas and confers antibiotic resistance to Trichomonas, have generated new interest in this field. In the present study we have generated specific nanobody against M. hominis (aMh), for which the identified target is the ABC-transporter substrate-binding protein. aMh exhibits specific antibacterial action against M. hominis. In an attempt to improve the therapeutic properties, we have developed the adenoviral vector-based gene therapy approach for passive immunization with nanobodies against M. hominis. For better penetration into the mucous layer of the genital tract, we fused aMh with the Fc-fragment of IgG. Application of this comprehensive approach with a single systemic administration of recombinant adenovirus expressing aMh-Fc demonstrated both prophylactic and therapeutic effects in a mouse model of genital M. hominis infection

Titers of <i>M</i>. <i>hominis</i> in vaginal washes with “prophylactic” scheme of rAds inoculation.

<p>Vaginal washes were collected 5 days after <i>M</i>. <i>hominis</i> inoculation (6 days after rAds inoculation). Amount of <i>M</i>. <i>hominis</i> was evaluated with real-time PCR. The rAd5-CMV-PLAP-aMh-FcG2a group exhibited a significantly lower <i>M</i>. <i>hominis</i> titer (Student's t-test = 3.5; p<0.01). Ad-null n = 5, PBS n = 15, rAd5-CMV-PLAP-aMh-FcG2a n = 10, rAd5-CMV-PLAP-aMh-ILZ-HA n = 11. In the “prophylactic” scheme of rAds inoculation, the <i>M</i>. <i>hominis</i> titer was significantly decreased in the rAd5-CMV-PLAP-aMh-FcG2a group. The prophylactic scheme, however, is not practical for treating mycoplasma infection. In the “therapeutic” scheme, the number of animals diagnosed as positive at 7 days after inoculation with rAd5-CMV-PLAP-aMh-FcG2a (12 days after <i>M</i>. <i>hominis</i> inoculation) was significantly lower than that of the other groups. Nevertheless the mycoplasma titer was not significantly different among the infected animals in any of the groups and not informative due to the large variability in counts and the low number of infected animals in the rAd5-CMV-PLAP-aMh-FcG2a group (n = 2 at 3 days and n = 1 at 7 days).</p

Determination of affinity constants.

<p>Binding of antigen to aMh-FcG2a was determined by surface plasmon resonance using Biacore 3000 (GE Healthcare). Antigen concentration series 5.95 nM; 11.9 nM; 59.5 nM and 595 nM (colour) and 1:1 fitting (black) interaction antigen to aMh-Fc. The fitted constant are k_a = 1.78⁴ M^-1s^-1 and k_d = 1.06⁻⁴ s^-1 which results <i>K</i>_<i>D</i> = 5.94*10⁻⁹ M (R_max = 428 RU; chi² = 11.8). Evaluation included double reference subtraction.</p

rAd5-CMV-PLAP-aMh-FcG2a and control rAd5-CMV-PLAP-aMh-ILZ-HA constructions and purification.

<p>(A) Scheme of expression cassettes for rAd5-CMV constructions; (B) sizing of purified Ad5-CMV-PLAP-aMh-FcG2a corresponding to virions suspensions with a particle size of ~100 nM.</p

Hypothetical mechanism of blocking nutrient acquisition through ABC transporter with aMh-FcG2a.

<p>Hypothetical mechanism of blocking nutrient acquisition through ABC transporter with aMh-FcG2a.</p

Dimer formations of aMh-FcG2a.

<p>Protein samples aMh-FcG2a were prepared before electrophoresis in sample buffer with or without DTT (as reducing agent), canonical mouse IgG2a was prepared with DTT and used as control. Protein bands ~42 and ~84 kDa corresponding monomer and dimer forms of aMh-Fc; protein bands ~54 kDa and 25 kDa corresponding heavy and light chains of canonical mouse IgG2a.</p