Genetic determinants of virulence and drug resistance of <i>Mycobacterium avium</i> subsp. <i>hominissuis</i> — a causative agent of mycobacteriosis in humans

Among the members of the large group of non-tuberculous mycobacteria (comprising more than 180 species), M. avium subsp. hominissuis (MAH) is the most significant causative agent of pulmonary infection in immunocompetent individuals as well as disseminated infection in immunocompromised hosts, e.g. human immunodeficiency virus (HIV)-positive patients. Due to increased incidence rate of mycobacteriosis, especially in HIV infection, much still need to be learnt about the MAH genetic control and virulence mechanisms. Deciphering the genome contents of the M. avium strain 104 (isolated from an AIDS patient with disseminated MAH disease) allowed to compare genome sequences of M. avium strains to gain insights into genomic diversity associated with variable hosts and environments. Comparative genome analysis of MAH strains isolated from patients with pulmonary and disseminated forms of mycobacteri-osis revealed differences in the structure of the genome, affecting the key virulence genes. This review provides current data on the genetic determinants of MAH virulence associated with the initial phase of infection. Several mycobacterial virulence-associated gene families, such as mce (mammalian cell entry), mmp (mycobacterial membrane proteins), pe/ppe and esx expressed by MAH during human infection are thought to be crucial for adhesion, entry, survival, and reproduction inside host macrophages. The genetic mechanisms of MAH survival in human macrophage cell culture as well as mice exposed to toxic effects of reactive oxygen, nitric oxide, bactericidal proteins (cathelicidin) are discussed. The MAH survival in the latency-like state is important for pathogen dissemination. Some genetic and phenotypic features of MAH (absence of a cord factor, presence of plasmids, potential to “switch” morphological types of colonies) are compared with M. tuberculosis. In addition, we summarized current state of MAH drug discovery, a role of MAH intrinsic multidrug resistance, genetic control, as well as mechanisms underlying formation of resistance to various groups of antibiotics in MAH strains

Electrochemical investigations of surfactants influence on copper ions cementation

The paper presents the results of experiments aimed to determine the effect of surfactants on the cementation rate and activation energy. The study was carried out on model solutions with the addition of surfactants. The results of the study showed that sodium lignosulfonate in a mixture with sodium dodecyl sulfate and sodium dodecylbenzene sulfonate increases the cementation rate over the entire range of studied concentrations. It is noted that the addition of individual surfactants leads to an increase in activation energy. Activation energy increases according to following order: sodium dodecylbenzene sulfonate → sodium dodecyl sulfate → sodium lignosulfonate. © Published under licence by IOP Publishing Ltd.Russian Science Foundation, RSF: 18-19-00186Leaching experiments and grade size analysis were conducted at the expense of the Russian Science Foundation grant (project No. 18-19-00186)

Intercultural projects as a means of developing universal competences of students

This article is devoted to the process of developing learners' universal competences connected with communicative skills, including skills of international communication, which are in demand in modern world and thus professionally important.Статья посвящена формированию у обучающихся универсальных компетенций, связанных с коммуникативными навыками, в том числе чрезвычайно важными в профессиональном отношении и востребованными в современном мире навыками межкультурного общения

EXPERIMENTAL MODELING OF APOPTOSIS UNDER CONDITIONS OF STABLE STRONTIUM EXPOSURE

Apoptosis is defined as a highly regulated form of programmed cell death with typical morphological and biochemical features. A variety of factors, including heavy metals, may influence the intensity of programmed cell death. The aim of the work was to simulate apoptosis in an in vitrosystem under the conditions of stable strontium exposure. The children’s population consuming drinking water with high strontium (Sr2+) content (n = 49) was observed. The level of lymphocyte apoptosis was determined with flow cytometry technique, by means of labeled annexin V-FITC conjugate (AnnV-FITC) and propidium iodide (PI) staining. AnnV-FITC+PI- cells were regarded as early apoptotic forms, whereas late apoptotic and/or necrotic cells were AnnV-FITC+PI+. The isolated leukocytes were incubated with Sr2+ at a concentration of 7.0 mg/l, the maximal permitted concentration (MPC) for water of aqueous objects, for 4 hours at 37 ºC. Expression of CD95 and p53 apoptosis markers was performed by flow cytometry using labeled monoclonal antibodies.In vitroexposure to strontium was associated with significantly decreased expression of apoptosisregulating factors, i.e., membrane marker CD95 and intracellular transcription protein p53, 1.56- and 1.68-fold, respectively. Meanwhile, we revealed a significantly (4.68-fold) decreased amounts of AnnV-FITC+PI--cells, as well as a statistically significant (1.35-fold) increase of the AnnV-FITC+PI+-cells. Moreover, the amounts of AnnV-FITC+ PI--lymphocytes in all samples were below the physiological ranges and control values. The number of samples with higher contents of AnnV-FITC+PI+-lymphocyte exceeding the established standards and control values, was 30.8%. Thus, it has been experimentally proven that strontium, at a concentration corresponding to MPC for water objects may significantly inhibit cell death along apoptotic pathways, with switching to necrotic cell death mechanisms, according to phosphatidylserine contents, as detected by annexin V binding test. The data have revealed an ability of strontium to have a significant effect upon the parameters of regulation and maintenance of cellular homeostasis, by influencing the apoptosis intensity, due to shifting a balance towards necrosis and reducing expression of apoptosis-regulating factors. The results of this study may be used in order to identify some marker indexes of immune disorders potentially induced by external influence of strontium upon human health under specific environmental factors

The isolated proteolytic domain of Escherichia coli ATP-dependent protease Lon exhibits the peptidase activity

AbstractSelective protein degradation is an energy-dependent process performed by high-molecular-weight proteases. The activity of proteolytic components of these enzymes is coupled to the ATPase activity of their regulatory subunits or domains. Here, we obtained the proteolytic domain of Escherichia coli protease Lon by cloning the corresponding fragment of the lon gene in pGEX-KG, expression of the hybrid protein, and isolation of the proteolytic domain after hydrolysis of the hybrid protein with thrombin. The isolated proteolytic domain exhibited almost no activity toward protein substrates (casein) but hydrolyzed peptide substrates (melittin), thereby confirming the importance of the ATPase component for protein hydrolysis. Protease Lon and its proteolytic domain differed in the efficiency and specificity of melittin hydrolysis

Аcinetobacter baumannii bv Tryptophandestruens bv nov. isolated from clinical samples

The aim of the study was to determine the taxonomic status of a group consisting of atypical strains of Acinetobacter baumannii, outline relevant characteristics and methods necessary for their identification. There were examined 10 strains of A. baumannii (6 of them primary comprised) bearing similar profile of atypical features isolated from clinical samples (urine, sputum) in 2017–2019 at the Military Medical Academy. Сlinical strains of typical A. baumannii (n = 36), Acinetobacter nosocomialis (n = 14), Acinetobacter pittii (n = 9) and 1 strain of Acinetobacter calcoaceticus isolated from the external environment were used in comparative studies. Atypical strains had the characteristics of A. calcoaceticus — A. baumannii (ACB) complex bacteria and were identified as A. baumannii. The utilization of substrates as the only carbon source was studied on a dense synthetic medium added with 0.2 % substrate during incubation for 72 hours at 37°C. Carbohydrate oxidation coupled to acid formation was detected on the Hugh–Leifson medium by using a micromethod. Aromatic amino acid biotransformation was carried out in liquid and dense nutrient media assessed in chromogenic reaction. The rpoB gene was used for strain genetic characterization. Amplification of two 940 and 1210 base pair (bp)-long fragments from the rpoB gene was performed by the routine polymerase chain reaction using primers with previously described sequences. Amplification products were sequenced by Sanger using Big Dye Terminator v3.1 (Applied Biosystems, USA) and capillary electrophoresis on an automatic sequencer ABI PRISM 3130 (Applied Biosystems, USA), followed by using methods for determining the similarity levels of sequenced fragments with the rpoB gene sequences of the reference strain A. baumannii ATCC 17978 (GenBank accession no. CP053098.1). It was found that all strains belonging to atypical A. baumannii spp. had a specific set of features that distinguish them from typical strains of A. baumannii as well as other types of the ACB complex: detected biotransformation of L-tryptophan (via anthranilate pathway) and anthranilic acid under unambiguous lack of such signs in other bacteria; lack of utilized sodium hippurate and L-arabinose being unambiguously evident in other bacteria; lack of utilized L-tryptophan, putrescine, L-ornithine being utilized in the majority of strains of belonging to other bacterial species. Genetic analysis showed that the control strains of typical A. baumannii displayed 99.20–99.21% similarity within the sequenced fragments of the rpoB gene with those from the rpoB gene of the reference strain. All 10 strains of atypical A. baumannii had similar features (99.20–99.21%). At the same time, parameters of control strains from other bacterial species significantly differed: A. nosocomialis (95.10–95.97%), A. pittii (94.63–94.92%), A. calcoaceticus (93.00%). Hence, the strains of atypical and typical A. baumannii are genetically homogeneous and belong to the same species. The data presented allow us to consider this group of atypical A. baumannii strains as a new biovar. We propose the name for this new biovar — tryptophandestruens (tryptophan-destroying) stemming from the Latin word destruens — destroying. Identification of A. baumannii bv. tryptophandestruens bacteria can be carried out in laboratory of any level by using tests for L-tryptophan biotransformation as well as sodium hippurate utilization

CLINICAL EXAMPLE OF THE USE OF LIPOFILLING WITH DELAYED RECONSTRUCTION

Malignant breast tumors are one of the causes of disability due to lack of breast or having operational defects. In most cases, the quality of the operation depends on the further social and active patient behavior.This article presents a clinical case of the use of lipofilling with reconstructive plastic surgery in breast cancer patients after complex treatment. In the particular example we show the positive effects after one session of conducted lipofiling in front of the chest wall to the right with Body-Jet hardware techniques. The purpose of this procedure was to improve the quality of cover fabrics in postoperative scar on the anterior chest wall right after comprehensive treatment, including also a cover for the such aggressive tissue treatment, as radiotherapy.It is proved that mesenchymal stromal cells, or cell-messengers that are present in all the fatty tissues, contribute to its regeneration by forming new blood vessels, or act directly on the damaged or exposed to aging structure — restore and rejuvenate the field of lipofilling. Therefore, adipose tissue is laid down by the nature of the human body a source of regeneration. In this clinical example, after successfully conducted one session of lipofilling marked improvement in skin quality in postoperative scar made after mastectomy and radiotherapy. Good autofat graft survival rate is also fixed, which was enough to implement further stages of breast reconstruction

Лекарственная чувствительность клинических изолятов Mycobacterium avium complex

The objective: to study drug susceptibility of M. avium and M. intracellulare isolates received from patients with mycobacteriosis residing in the North Western Federal District using the Sensititre SLOMYCO panels.Subjects and Methods. From 2014 to 2020, 192 slow-growing MAC strains (164 – M. avium, 28 – M. intracellulare) obtained from HIV-negative patients with pulmonary mycobacteriosis were studied. Drug susceptibility testing of MAC strains was performed using the Sensititre SLOMYCO panel consisting of 13 antibacterial drugs.Results. Of the 13 antibacterial drugs, clarithromycin was also most effective against both M. avium (67.1%; 110/164) and M. intracellulare (60.7%; 17/28) (p &gt; 0.05). The proportion of M. avium and M. intracellulare strains sensitive to linezolid was high and amounted to 57.3 and 53.5%, as well as to amikacin – 57.3 and 53.5% respectively.Of the four antibacterial drugs of the Sensititre SLOMYCO panel (clarithromycin, moxifloxacin, linezolid, and amikacin), for which critical concentrations (CC) were established, clarithromycin was the most effective against M. avium and M. intracellulare. Antibiotic-resistant M. avium isolates were more frequent in the group of previously treated patients.Цель исследования: изучение чувствительности изолятов M. avium и M. intracellulare, выделенных от больных микобактериозом на территории Северо-Западного федерального округа, к антибактериальным препаратам с использованием панелей Sensititre SLOMYCO.Материалы и методы. За период с 2014 по 2020 г. изучены 192 медленнорастущих штамма MAC (164 ‒ M. avium, 28 ‒ M. intracellulare), полученных от ВИЧ-негативных больных микобактериозом легких. Определение лекарственной чувствительности штаммов МАС выполняли с использованием панели из 13 антибактериальных препаратов Sensititre SLOMYCO.Результаты исследования. Из 13 антибактериальных препаратов кларитромицин также оказался наиболее эффективным в отношении как M. avium (67,1%; 110/164), так и M. intracellulare (60,7%; 17/28) (p &gt; 0,05). Доля чувствительных к линезолиду штаммов M. avium и M. intracellulare была высока и составляла 57,3 и 53,5%, к амикацину – 57,3 и 53,5% соответственно.Из четырех антибактериальных препаратов панели Sensititre SLOMYCO (кларитромицина, моксифлоксацина, линезолида и амикацина), для которых установлены критические концентрации (КК), наиболее эффективным в отношении M. avium и M. intracellulare являлся кларитромицин. Резистентные к антибиотикам изоляты M. avium чаще встречались в группе ранее леченных больных

ВОЗМОЖНОСТИ ЛЕКАРСТВЕННОЙ ТЕРАПИИ АНДРОГЕН-ПОЗИТИВНОГО РАКА МОЛОЧНОЙ ЖЕЛЕЗЫ

There are some types of breast cancer (BC) that depend on their molecular characteristics. However, lately researchers provide date regarding the presence of additional receptors of triple negative breast cancer (TNBC). One of them is LA R-subtype that has androgen receptors (AR) on breast cancer cells. The role of AR in the development of this pathology is still controversial. According to some authors, stimulation of AR leads to the proliferation suppression, in the opinion of others – to the activation and potentiation of tumor invasion. There is also a version of the dichotomous effect of androgens that depends on the concentration of this hormone. The various effects of LA R-subtype therapy of BC are also explained by the presence of many other regulator proteins that interact with AR. The first attempts to treat BC with androgen have begun since the 40s of the last century, but in those years it did not have the desired effect and was not used until recently. Currently, the basic mechanisms of the effect of androgens on BC cells on the molecular level are known, and researches try to use androgen therapy, also in combination with aromatase inhibitors to increase the concentration of endogenous testosterone. The effects of selective androgen receptor modulators and anabolic steroids are being studied. However, in the last decade, the largest number of studies focused on the study of anti-androgen therapy. Patients receive AR antagonists, such as enzalutamide, bicalutamide, that are prescribed for prostate cancer. Enzalutamide blocks both androgen- and estrogen-mediated tumor growth, and therefore can be used regardless of the presence of estrogen receptors (ER), in contrast to bicalutamide. The results showed a significant increase in disease free survival up to 16.5 months in patients with hormone positive BC.Существует несколько типов рака молочной железы (РМЖ) в зависимости от их молекулярных характеристик. В последних публикациях мировой литературы приводятся данные о наличии дополнительных подтипов тройного негативного РМЖ. Одним из них является laR-подтип, который характеризуется наличием андрогеновых рецепторов (АР). Роль АР в развитии РМЖ до сих пор остается спорной. По мнению одних авторов, стимуляция АР приводит к подавлению пролиферации, по мнению  других, – к ее активации и потенцированию инвазии опухоли. Существует версия о дихотомическом эффекте андрогенов в зависимости от концентрации гормона. Также направление эффекта терапии laRподтипа зависит от множества других белков- регуляторов, взаимодействующих с АР. В 1940-х гг. прошлого века были предприняты первые попытки лечения РМЖ препаратами андрогенового ряда, однако без значительного эффекта, в связи с чем они больше не применялись до начала XXi века. В настоящее время известны основные механизмы действия андрогенов на клетки РМЖ. В рамках научных исследований предпринимаются попытки андрогеновой терапии, в том числе в сочетании с ингибиторами ароматазы с целью увеличения концентрации эндогенного тестостерона. Изучаются эффекты селективных модуляторов рецепторов андрогенов и анаболических стероидов. Однако в последнее десятилетие  наибольшее количество исследований направлено на изучение антиандрогеновой терапии антагонистами АР, такими как энзалутамид и бикалутамид. При этом энзалутамид блокирует как андроген-, так и эстроген-опосредованный рост опухоли, в связи с чем может применяться вне зависимости от наличия эстрогеновых  рецепторов (РЭ) в отличие от бикалутамида. Результаты одного из крупнейших исследований энзалутамида в сочетании с экземестаном показывают значительное увеличение выживаемости без прогрессирования у пациенток с гормон-позитивным РМЖ – до 16,5 мес (по сравнению с 4,3 мес в контрольной группе)

Биопсия сторожевого лимфатического узла при раке молочной железы с применением метода флуоресцентной визуализации красителя индоцианин зеленый

We presented the preliminary results of sentinel lymph node biopsy (SLN) using the method of fluorescent visualization with the indocyanine green. The study included 40 breast cancer patients with the prevalence of the cTis-2N0M0 process. 1 ml of Indocyanine Green (ICG) aqueous solution was administered periareolarly and subcutaneously from the tumor side with total drug dose of 5 mg. In the following few minutes the ICG trail along the lymphatic vessels was observed by its fluorescence in the infrared spectral range using a special camera with image transmitted to a computer screen. After the trail reached the axillary region and broke off, skin and subcutaneous tissue incision in axillary area was made, and the superficial fascia was dissected. The first contrasted lymph nodes were extracted. The incidence of SLN was 92.5%. Metastases were detected in 20% of cases. On average, it took 17.6 minutes to identify and remove the SLN. In 7 patients the use of the fluorescent SLN detection method was combined with radioisotope (Technefite 99m Tc colloid) – in all cases the same SLN was identified. The use of the ICG lymphotropic dye with the subsequent detection of SLN by the fluorescence method makes it possible to diagnose the status of SLN with a high degree of accuracy and can be comparable in effectiveness with the isotopic method. The specificities of lymphatic drainage were found out with the use of fluorescence lymphography: inverse dependence of the lymphatic drainage rate on the body mass index and breast size, and absence of dependence on degree of ptosis of breast.В работе представлены результаты исследования биопсии сторожевого лимфатического узла (СЛУ) с помощью метода флуоресцентной визуализации красителя индоцианин зеленый. В исследование были включены 40 больных раком молочной железы с распространенностью процесса сTis-2N0M0. 1 мл водного раствора красителя индоцианина зеленый вводили периареолярно внутрикожно и подкожно со стороны опухоли в дозе активного вещества 5 мг. В ближайшие минуты наблюдали движение красителя по лимфатическим путям в виде «дорожки» способом флуоресценции в инфракрасном спектре с помощью специальной камеры с передачей изображения на экран компьютера. После того, как дорожка достигала подмышечной области и обрывалась, производили разрез кожи и подкожной клетчатки в подмышечной области, рассекали поверхностную фасцию. Выделяли первые контрастиро ванные лимфатические узлы. Частота выявления СЛУ составила 92,5%, из них метастазы выявлены в 20% случаях. В среднем на этап идентификации и удаления СЛУ уходило 17,6 мин. У 7 больных комбинировали применение метода флуоресцентного (краситель ICG) определения СЛУ с радиоизотопным (коллоид Технефит 99m Tc) – во всех случаях идентифицировали одни и те же СЛУ. Применение лимфотропного красителя индоцианина зеленого с последующим выявлением СЛУ методом флуоресценции позволяет с высокой степенью точности диагностировать состояние СЛУ, а также сопоставимо по эффективности с изотопным методом. Выявлены осо бенности лимфооттока в молочной железе с помощью флуоресцентной лимфографии: обратная зависимость скорости лимфоотто ка от индекса массы тела и размера молочной железы, отсутствие зависимости от степени птоза железы