Sensitivity of human lymphocytes to genotoxic effect of N-methyl-N-nitrosourea: possible relation to gynecological cancers

The aim of this work is to study responses of PHA-stimulated and resting lymphocytes to methylating agent N-methyl-N-nitrosourea (MNU) and to compare sensitivity to this agent of healthy donor lymphocytes and lymphocytes from patients with gynecological cancers. Methods: Cytotoxicity of MNU, apoptotic death of lymphocytes, was evaluated using two common tests – annexin V-FITC detection assay and live/dead double staining assay (nuclear morphological changes). Genotoxic effect of the agent was determined as delayed (secondary) DNA double strand breaks (DSBs) using neutral comet assay both conventional variant and modified for detection of bromodeoxyuridine-labelled comets, produced by proliferating lymphocytes only. Results: Unstimulated lymphocytes were tolerant to geno- and cytotoxic effects of MNU. In contrast to resting cells, proliferating lymphocytes showed significant genotoxicity (p = 0.0054) of MNU followed by increased apoptotic death of cells (p < 0.05). Average number of secondary DSBs induced by MNU in lymphocytes from patients with gynecological cancers was about 4-fold less than that of lymphocytes of healthy donors. While lymphocytes from cancer patients did not change proliferative index in response to MNU, the agent decreased 2-fold proliferative indices of stimulated lymphocytes from healthy donors. Conclusion: There is a reverse association between geno- and cytotoxicity of MNU in stimulated lymphocytes and the presence of tumor. The relationship appears to be based on MMR-insufficiency in lymphocytes of the cancer patients.Цель: исследование эффекта метилнитрозомочевины (МНМ) на ФГА-стимулированные лимфоциты и в состоянии покоя здоровых доноров и пациенток с опухолями женской половой сферы. Методы: цитотоксический эффект МНМ (апоптотическая гибель лимфоцитов) оценивали по двум показателям — взаимодействию клеток с комплексом annexin V-FITC и по морфологическим изменениям ядра клеток после их окрашивания смесью 2 ДНК-тропных красителей. Генотоксический эффект МНМ, вторичные двунитевые разрывы ДНК (ДР) определяли с помощью метода нейтральных ДНК-комет. Использовали стандартный вариант метода и модифицированный для подсчета комет, формируемых только делящимися лимфоцитами, меченными BrUdr. Долю таких комет представляли как индекс пролиферации клеток. Результаты: лимфоциты в состоянии покоя устойчивы к гено- и цитотоксическому эффектам МНМ. В пролиферирующих клетках в ответ на воздействие МНМ формировались вторичные разрывы ДНК (р < 0,01) и возрастала частота появления апоптотических клеток (р < 0,05). Генотоксический эффект МНМ на стимулированные лимфоциты больных онкологического профиля в 4 раза ниже, чем на лимфоцитах здоровых доноров. Лимфоциты пациенток не изменяли пролиферативный индекс в ответ на действие МНМ; в лимфоцитах здоровых доноров действие МНМ вызывало 2-кратное снижение пролиферативного индекса. Выводы: установлена связь между гено- и цитотоксическим ответом лимфоцитов на действие МНМ и наличием опухоли. Предполагается, что генотоксический эффект МНМ связан с процессом пострепликативной коррекционной репарации

Magnetic-field- and temperature-dependent fermi surface of CeBiPt

The half-Heusler compounds CeBiPt and LaBiPt are semimetals with very low charge-carrier concentrations as evidenced by Shubnikov–de Haas (SdH) and Hall-effect measurements. Neutron-scattering results reveal a simple antiferromagnetic structure in CeBiPt below TN = 1.15 K. The band structure of CeBiPt sensitively depends on temperature, magnetic field and stoichiometry. Above a certain, sample-dependent, threshold field (B>25 T), the SdH signal disappears and the Hall coefficient reduces significantly. These effects are absent in the non-4f compound LaBiPt. Electronic-band-structure calculations can well explain the observed behaviour by a 4f-polarization-induced Fermi-surface modification

Magnetic-field- and temperature-dependent fermi surface of CeBiPt

The half-Heusler compounds CeBiPt and LaBiPt are semimetals with very low charge-carrier concentrations as evidenced by Shubnikov–de Haas (SdH) and Hall-effect measurements. Neutron-scattering results reveal a simple antiferromagnetic structure in CeBiPt below TN = 1.15 K. The band structure of CeBiPt sensitively depends on temperature, magnetic field and stoichiometry. Above a certain, sample-dependent, threshold field (B>25 T), the SdH signal disappears and the Hall coefficient reduces significantly. These effects are absent in the non-4f compound LaBiPt. Electronic-band-structure calculations can well explain the observed behaviour by a 4f-polarization-induced Fermi-surface modification

FeCl3, CuSO4, CoCl2, ZnSO4 and NiSO4 effect on a gelatinolytic activity of proteinases of Pleurotus ostreatus mycelial culture

The effect of FeCl3, CuSO4, CoCl2, ZnSO4 and NiSO4 at a concentration of 10–8–10–2 M on the gelatinolytic activity of intracellular proteinases from in 14 days mycelial culture of Pleurotus ostreatus was studied. At pH 5.8, all salts inhibited activity within 30%. Only zinc sulfate in several concentrations contributed to a weak increase in proteinase activity: up to 16%. The gelatinolytic activity at pH 7.6 is characterized by the activating effect of copper sulfate in the entire range of concentrations, reaching 25–67%. The gelatinolytic activity upon the addition of cobalt chloride was suppressed more strongly than in an acidic medium at a CoCl2 concentration of 10–6 M, by 53%. At the same time, at two maximum concentrations of this effector, gelatinolysis increased by 25 and 31%. The maximum activator effect of nickel sulfate manifested itself at a concentration of 10–2 M and reached 137%, while at concentrations of 10–4 and 10–5 M, proteolysis was suppressed by 26 and 22%. At pH 9.2, CuSO4 had a clear activating effect (up to 157% relative to control) in almost the entire concentration range. The effect of other salts did not exceed 24%.Изучено влияние FeCl3, CuSO4, CoCl2, ZnSO4 и NiSO4 в концентрации 10–8–10–2 М на желатинолитическую активность внутриклеточных протеиназ 14-ти суточной мицелиальной культуры Pleurotus ostreatus. При рН 5,8 все соли угнетали активность в пределах 30%. Лишь сульфат цинка в нескольких концентрациях способствовал слабому росту активности протеиназ: до 16%. Для желатинолитической активности при рН 7,6 характерен активаторный эффект сульфата меди во всем диапазоне концентраций достигавший 25–67%. Желатинолитическая активность при добавлении хлорида кобальта угнеталась сильнее, чем в кислой среде при концентрации CoCl2 10–6 М – на 53%. В то же время при двух максимальных концентрациях этого эффектора желатинолиз возрастал на 25 и 31%. Максимальный активаторный эффект сульфата никеля проявился при концентрации 10–2 М и достигал 137%, тогда как при концентрациях 10–4 и 10–5 М протеолиз подавлялся на 26 и 22%. При рН 9,2 четкое активаторное действие (до 157% по отношению к контролю) практически во всем концентрационном диапазоне оказал CuSO4. Эффект остальных солей не превышал 24%

Structure of Neuroglobin from Cold-Water Sponge Halisarca dujardinii

© 2020, Pleiades Publishing, Inc. Abstract: The iron-containing protein neuroglobin (Ngb) involved in the transport of oxygen is generally considered the precursor of all animal globins. In this report, we studied the structure of Ngb of the cold-water sponge Halisarca dujardinii. In sponges, the oldest multicellular organisms, the Ngb gene contains three introns. In contrast to human Ngb, its promoter contains a TATA-box, rather than CG-rich motifs. In sponges, Ngb consists of 169 amino acids showing rather low similarity with its mammalian orthologues. It lacks Glu and Arg residues in positions required for prevention of hypoxia-related apoptosis. Nevertheless, Ngb contains both proximal and distal conserved heme-biding histidines. The primary structure of H. dujardinii neuroglobin predicted by sequencing was confirmed by mass-spectrometry analysis of recombinant Ngb expressed in E. coli. The high level of Ngb expression in sponge tissues suggests its possible involvement in the gas metabolism and presumably in other key metabolic processes in H. dujardinii

Structure of Neuroglobin from Cold-Water Sponge Halisarca dujardinii

The iron-containing protein neuroglobin (Ngb) involved in the transport of oxygen is generally considered the precursor of all animal globins. In this report, we studied the structure of Ngb of the cold-water sponge Halisarca dujardinii. In sponges, the oldest multicellular organisms, the Ngb gene contains three introns. In contrast to human Ngb, its promoter contains a TATA-box, rather than CG-rich motifs. In sponges, Ngb consists of 169 amino acids showing rather low similarity with its mammalian orthologues. It lacks Glu and Arg residues in positions required for prevention of hypoxia-related apoptosis. Nevertheless, Ngb contains both proximal and distal conserved heme-biding histidines. The primary structure of H. dujardinii neuroglobin predicted by sequencing was confirmed by mass-spectrometry analysis of recombinant Ngb expressed in E. coli. The high level of Ngb expression in sponge tissues suggests its possible involvement in the gas metabolism and presumably in other key metabolic processes in H. dujardinii