Aim. To study the chemical composition, sugar specificity and physicochemical properties of the extracellular lectin isolated from Bacillus subtilis ІМV В-7724. Methods. Biochemical, spectrophotometric, immunological and cultural methods were used to assess the physicochemical and a number of biological properties of lectin isolated from the culture fluid of bacteria B. subtilis ІМV В-7724. Molecular weight of the lectin was estimated in polyacrylamide gel electrophoresis. Analysis of the elemental composition was done using Perkin-Elmer 2400 CHNS analyzer. Temperature and pH stability of lectin were examined based on residual hemagglutination activity of the lectin. Cytotoxic activity was determined by the MTT-assay. The statistical analysis was made using Student’s t-test. Results. B. subtilis IMV B-7724 lectin is a glycoprotein (protein – 86.0%, carbohydrates – 7.0%) with molecular weight of 18–20 kDa (major). Analysis of the elemental composition revealed that it contains 34.00% of carbon, 7.04% of hydrogen, 16.61% of nitrogen, 42.35% of oxygen. Amino acid composition analysis determined that it is rich in leucine, tyrosine and phenylalanine. The lectin exhibited high sugar-binding specificity toward N-acetylneuraminic and N-glycolylneuraminic acids (minimal inhibitory concentration – 0.3 mM for both sugars). The lectin is heat and acid stable, has long shelf life. Conclusions. These results provide the rationale to pursue further investigation for possible ways and modes of B. subtilis IMB B-7724 lectin application in clinical settings.
Summary. Background: The impact of growing tumor on polarization and functions of tumor-associated macrophages is well known while its influence on residential macrophages occupying different anatomical niches reminds to be elucidated. Aim: To study changes in polarization and functions of macrophages isolated from discrete anatomical niches in tumor-bearing mice at different stages of tumor growth. Materials and Methods: Ehrlich carcinoma was transplanted intramuscularly to Balb/c male mice. On days 7, 14, 21 and 28 after tumor transplantation, macrophages from tumor tissue, peritoneal cavity and spleen were isolated and analyzed. Nitric oxide production was measured by standard Griess reaction, arginase activity was determined by the measurement of urea, reactive oxygen species production was checked using NBT dye reduction assay and electron paramagnetic resonance spectroscopy, cytotoxic activity was estimated in MTT-assay. Results: Independently of their localization in different anatomic niches, macrophages in mice with transplanted Ehrlich carcinoma gradually lose their tumoricidal activities while arginase activity is upregulated. This indicates the shift of polarization from M1-like towards M2-like phenotype. Conclusion: Our findings demonstrated that growing tumor could be able to subvert functioning of macrophages at the systemic level.
Мета дослідження – оцінити параметри гострої токсичності лектину B. subtilis IMB B-7724 за умови його одноразового введення мишам двох ліній.Дослідження виконані на мишах ліній Balb/c (n = 96) і C57Bl (n = 96). Шляхи введення лектину: підшкірний (п/ш), внутрішньоочеревинний (в/о), пероральний (per os). Використані дози лектину: 125, 250, 375, 500 мг/кг ваги тварини (п/ш і в/о); 500 мг/кг (per os). Мишам контрольної групи вводили фізіологічний розчин NaCl. За показниками виживаності та смертності визначали максимально переносиму (LD0) та смертельну (LD100) дози; проводили розрахунок середньосмертельної дози (LD50) за методами Кербера та Беренса.LD50 лектину B. subtilis IMB B-7724 у разі його введення per os і п/ш мишам ліній Balb/c і C57Bl перевищувала максимальну досліджувану дозу (500 мг/кг). В/о введення лектину B. subtilis IMB B-7724 супроводжувалось дозозалежним токсичним впливом: LD0 = 125 мг/кг, LD16 = 132 мг/кг, LD100 = 500 мг/кг. Показники LD50, які розраховані за двома різними методами, суттєво не відрізнялись і складали 278,8–281,3 мг/кг (для мишей лінії Balb/c) і 231,1–250,0 мг/кг (для мишей лінії C57Bl). Оцінка параметрів гострої токсичності дозволяє віднести досліджуваний лектин B. subtilis IMB B-7724 до малотоксичних речовин. Отримані результати свідчать про доцільність проведення подальших доклінічних досліджень з метою розробки на основі даного бактеріального лектину нового терапевтичного засобу.
Aim: To assess the functional state of macrophages based on various manifestations of their activity at the different stages of metastatic tumor growth in C57Bl mice. Materials and Methods: On days 7, 14, 21 and 28 after Lewis lung carcinoma transplantation to C57Bl mice, macrophages from various anatomic sites were isolated and tested on their cytotoxicity, metabolic activity, NO production and arginase activity. Results: In the populations of peritoneal and splenic macrophages, on days 7 and 21 of tumor growth antitumor (M1) cells prevailed while on days 14 and 28 tumor-promoting (M2) macrophages predominated. In the population of lung macrophages, cells with M1 phenotype were in the majority in the early stages of tumor growth. On days 21 and 28, M1 cells were gradually substituted by cells exhibiting M2 phenotype. This shift correlated with metastasis to lungs. Conclusion: Lewis lung carcinoma growth is accompanied by the gradual change in macrophage polarization from antitumor (M1) towards tumor-promoting (M2) type. These changes were more evident in population of lung macrophages and correlated with the parameters of metastasis.
The level of oxygen mass transfer (KV) is an important parameter influencing the growth rate of aerobic microorganisms and the synthesis of metabolites. It is mainly determined by the agitation and the aeration rates in the fermenter. Aim. To study changes in pH, optical density (OD), and hemagglutinating (lectin) activity (HAA) of culture fluid (CF) of Bacillus subtilis strain IMV B-7724, a producer of extracellular cytotoxic lectin (ECL), during its cultivation in a laboratory fermenter at different agitation and aeration rates as well as to determine and compare the HAA, carbohydrate specifi city, and cytotoxic properties of the corresponding samples of the preparation isolated from CF. Methods. Batch antifoam-free fermentations were performed by culturing the strain in the modified Gause medium with galactose in two identical lab-scale fermenters with a working volume of 2.5 L at 37ºC for 48—72 h according to three fermentation variants. Variant 1: n — 400 rpm for the whole cultivation, the air supply to the CF — through a sparger at 0.1 vvm until the 39th h with further gradual decrease, KV — 4.2±0.3 g O2·L−1·h−1. Variant 2: n — 400 rpm for the first 24 h, then a gradual decrease to 200 rpm, air supply — through a sparger at 0.1 rpm for the first 12 h, followed by its switching into the fermenter free space, corresponding KV — from 4.2±0.3 to 0.3±0.1 g O2·L−1·h−1. Variant 3: n — 400 rpm and air supply to the fermenter free space during the whole cultivation, KV — 4.0±0.3 g O2·L−1·h−1. A number of biological properties of strain CF and isolated lectin samples were evaluated by biochemical, spectrophotometric, immunological, and culture methods. Statistical analysis was performed using Student’s t-test. Results. The maximum increase in the OD of CF relative to the initial values (28 and 21-fold) at the end of the period of the rapid growth of the strain (at 9th h), the μmax values of 0.33 and 0.41 h−1, and pH not lower than 6.7 and 6.3 units were observed for fermentation variants 1 and 2, respectively. In the case of variant 2, the HAA of CF reached 32 hemagglutinating units (HAU), and the samples isolated from it had a lectin activity of 512±64 HAU, whereas for variant 1 such values were lower:16 and 32±8 HAA, respectively; carbohydrate specificity of preparations to bovine submandibular gland mucin was the same, i.e. 0.2±0.1 mg/mL. In contrast to the above, a slower increase in the OD of the CF, a decrease in μmax, and significant acid formation (15-fold at the 9th h, 0.25 h−1, and pH decrease to 5.8 units, respectively) were observed for variant 3; in this case, the level of HAA of CF was minimal (2—4 HAU) and was absent in the corresponding isolated samples. The probable reason for such differences was the limited mass transfer in the CF due to the isolating effect of the foam layer on its surface formed as a result of intensive agitation. Conclusions. The rapid growth of the strain and an increase in the HAA of CF were observed during cultivation in a lab-scale fermenter by maintaining the maximum level of oxygen mass transfer with air supply into the CF through a sparger until the maximum OD was reached and the subsequent gradual decrease in the specifi ed level during further cultivation started.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.