Cyanein,a new antibiotic fromPenicillium cyaneum

Описываются выделение и некоторые особенности нового аптибиотика цианспина, полученного из Penicilliu, cyaneum. Цианеин—это белое кристаллическое вещество, пеитральпото характера, с точкой плавления 199,8–201,8°C (a)_D ^{2 3} = + 82,7°. Он очснь слабо рас. творяется в воде, бензинеив петрольэ?ире, лучшс в этиловом спирте, ацетоне, поропилентликолс, п-бутаполс, этилацетате ив диэтилэ?ире. Циансин э??сктивен против Candida albicans и других грибков, не деиствует на исследовавшихся простейших и бактерии. Он заметно угнетаст размножение клеток HeLa, и его ID₅₀ для этих клеток составляет 0,01 μг/мл     

Vitamin B12 formation from various actinomycetes isolated from bulgarian soils

240 зтаммов актиномицетов, выделенных из ризосферы различных растений и из различных почв, исследовались на наличие витамина В₁₂ путем культивирования в жидкой питательной среде. 73% из исследованных штаммов обладают способностью образовывать витамин В₁₂, в количестван порядка 0,0025–1,6 μ/мл. Количество продуцентов зависит от растительного покрова. Серия Helvolus включает наибольшее количество продуцентов (93,3%).     

Biosynthesis of vitamin B12 and fungicidin byStreptomyces noursei

Актиномицет Streptomyces noursei, штамм 2–9, кроме фунгицидных антибиотиков, продуцирует также витамин B₁₂ в концентрации около 0,5 μг/мл среды. Факторы, в значительной степени повышающие (прибавление метанола) или же понижающие (понижение аэрации) продукцию фунгицидина, или вовсе не влияют на биосинтез витамина B₁₂, или только несколько его замедляют. Отсутствие ионов Co²⁺ вызывает существенное понижение продукции витамина B₁₂, но лишь незначительно влияет на выход фунгицидина. Это означает, что между обоими процессами биосинтеза не существует тесной связи.     

Spores of microorganisms X. Interference of tetracycline antibiotics with sporogenesis of Bacilli

Спорообразующие клетки бацилл, характеризующиеся чрезвычайно сильным накоплением кальция, служили моделью для изучения сущности действия тетрациклиновых антибиотиков на цельные клетки. В период образования преспор наблюдается усиление связывания клетками кальция. В тот же период резко повышается способность клеток Bacillus cereus и Bacillus megaterium связывать хлортетрациклин. Повидимому, как кальций, так и тетрациклин адсорбируются в этот период на поверхность клеток и могут быть отмыты различными методами промывания. Культивирование спорообразующих клеток с лимонной кислотой в значительной степени усиливает связывание хлортетрациклина с клетками. Хлортетрациклин, окситетрациклин и тетрациклин (в концентрации 3 µг/мл), блокируя поверхность клетки, по-видимому, резко тормозят внедрение кальция в клетки и синтез дипиколиновой кислоты в спорангиях, влияя так на морфологию оюразуюшихся спор и на автолиз спорангиев. Это их действие в значительной степени зависит от стадии развития культуры в момент прибавления к ней антибиотика. Избыток кальция в среде несколько повыwает образование дипиколиновой кислоты как в присутствии хлортетрациклина, так и в контроле. Избыток магния, марганци илп глюкозы не меняет торможения внедрения кальция. — Действие тетрациклиновых антибиотиков на спорообразование и на автолиз спорангиев сравнивается с действием этилендиаминтетрау ксусной кислоты. Полученные результаты обсуждаются с точки зрения теории блокады макромолекул и структур тетрациклиновыми антибиотиками через посредство металлов.     

Formation of osmotically fragile rods by the action of lysozyme onBacillus megaterium KM

1. (1)
   В течение непродолзительной инкубации Bacillus megaterium в среде с 0,5 M фосфатным буфером и лизоцимом (0,2 мг/мл) вознпкают осмотически хрупкие клетки.     
   
   

Investigation of submerged production of the antibiotic cyanein

В ходе глубинной ферментации Penicillium cyaneum исследовали зависимость выхода цианеина от состава ферментационной среды. Было установлено, что биосинтез антибиотика осуществляется и в простой синтетической среде с прибавлением микроэлэментов. При использовании сахарозы в качестве источника C, а KNO₃—в качестве источника N максимальная продукция 230 μг/мл была получена у неселекционированного штамма S-11 через 168 час.     

Survival of auxotrophic strains ofEscherichia coli in a minimal medium containing penicillin during isolation by the penicillin method

При выделении ауксотрофных штаммов микроорганизмов пенициллиновым методом в минимальной среде с пенициллином определенное количество ауксотрофов погибает.—Определялася зависимость количества выживающих ауксотрофов В. coli от общей концентрации бактерий в минимальной среде с пенициллином при выделении. Было установлено, что оптимальные условия для выделения ауксотрофов имели место при концентрации порядка 10⁴ клеток/мл минимальной среды с 220 м. ед. кристаллического пенициллина G/мл.     

Assay of lysine by means of a mutant ofEscherichia coli

Описывается простой и доступный турбидиметрический метод определения L-лизина с помощью мутанта Escherichia coli ATCC 12408, чувствительного к лизину. Это метод надежного определения количества лизина в пределах от 20 до 100 μг. Присутствие высоких концентраций аргинина или орнитина не оказывает влияния на точность метода.     

Computational Study of the Sulfonylated Amino Acid Hydroxamates Binding to the Zinc Ion within the Active Site of Carbonic Anhydrase

Abstract

The B3LYP/6–311+G(d,p) method and three ONIOM extrapolation methods ONI-OM (B3LYP/6–311+G(d,p): AM1); ONIOM(B3LYP/6–311+G(d,p): MNDO); ONIOM (B3LYP/6–311+G(d,p): HF/3-21G(d)) were used to characterize the complexes of Zn²⁺ cation with anionic sulfonylated amino acid hydroxamates (RSO₂NH-AA-CON(-)OH), possessing an unsubstituted RSO₂NH—amino acyl moiety. According to the R moiety we distinguish between pentafluorophenyl and 4-methoxyphenyl derivates. The amino acid hydroxamates included in the study were the Gly, Ala, and Leu derivates. Of the inhibitors investigated, the weakest zinc affinity exhibits the pentafluorophenyl derivate with Gly amino acid and the strongest affinity the 4-methoxyphenyl derivate with Leu amino acid. The inhibitors form bidentate coordination bonds with the zinc cation by means of the sulfonyl oxygen and the ionized hydroxamate nitrogen atoms, respectively. The zinc affinities computed using the B3LYP/6–311 +G(d,p)//HF/6–31 +G(d,p) method are in very good agreement with the full density functional theory (DFT) B3LYP/6–311+G(d,p)//B3LYP/6- 311+G(d,p) method and this method can be adopted to model larger complexes of inhibitors with the active site of carbonic anhydrase.     

Functional investigation of monoterpenes for improved understanding of the relationship between hosts and bark beetles

Spruce bark beetle (Ips typographus L.) is the most destructive insect pest of spruce forests in Eurasia. However, contact toxicity, in vivo metabolism, and ecological functions of host monoterpenes are poorly understood at the spruce tree–bark beetle–predator tritrophic level. Spruce monoterpenes including S-(–)-α-pinene, R-(+)-α-pinene, and myrcene showed contact toxicity to I. typographus, with LD₅₀ values ranging from 22–32 μg/mg. When topically treated with S-(–)-α-pinene or R-(+)-α-pinene, the amounts of volatile metabolites, including 4S-(–)-cis-verbenol, 4S-(+)-/4R-(–)-trans-verbenol, R-(+)-/S-(–)-verbenone and 1R-(–)-/1S-(+)-myrtenol, in the hindgut extracts of I. typographus varied significantly between sexes, and their quality (enantiomeric composition) varied significantly with the chirality of α-pinene. More importantly, S-(–)-α-pinene induced male adults to produce large amounts of 4S-(–)-cis-verbenol and S-(–)-verbenone. When topically treated with myrcene, the expected semiochemicals such as E-myrcenol, ipsenol and ipsdienol were not detected in the beetle hindguts, indicating that the pheromone biosynthetic system of I. typographus does not participate in the metabolism of host myrcene. In trap tests, S-(–)-α-pinene and R-(+)-α-pinene increased the catches of I. typographus and its predator Thanasimus substriatus in pheromone-baited traps, whereas myrcene exhibited a strong repellent (or inhibitory) effect on I. typographus but not on its predator. I. typographus seems to adopt different ecological strategies (e.g. avoidance to myrcene and preference for α-pinene) to adapt to and tolerate different host monoterpenes. Extensive investigation of these monoterpenes will help us understand their roles in manipulating the arms race between host trees and bark beetles, and potentially improve the efficacy of controlling I. typographus via the push-pull strategy using host kairomones.     

Binding Characteristics of the Muscarinic Receptor Subtype in Rabbit Pancreas

Abstract

The muscarinic receptor in the rabbit pancreas was characterized with the use of the labeled ligand (³H)-(-)-quinuclidinyl-benzylate ((³H)-(-)-QNB). Specific binding of (³H)-(-)-QNB to pancreatic acini was found to be reversible and of high affinity, with an equilibrium dissociation constant (K_D) of 68 pmol/l and a receptor density (R_T) of 170 fmol/mg protein. Agonist binding behaviour was investigated by displacement of (³H)-(-)-QNB binding by eight agonists like arecoline, arecaïdine-propargylester (APE) and carbachol, yielding only low affinity binding sites. The inhibition of (³H)-(-)-QNB binding by the selective antagonists pirenzepine, hexahydrosiladifenidol (HHSiD) and (11–(12–((diethyl - amino)- methyl)- 1– piperidinyl) acetyl)-5, 11-dihydro-6H-pyrido (2, 3–b) (1, 4) benzodiazepin-6–one) (AF-DX 116) confirmed the M₃ nature of the rabbit pancreatic receptor.     

Exosome-mediated transfer of CLIC1 contributes to the vincristine-resistance in gastric cancer

Molecular and Cellular Biochemistry - Aryl hydrocarbon-receptor nuclear translocator (ARNT2) is a member of the bHLH PAS (basic helix–loop–helix Period/ARNT/Single-minded) family of...     

DFT studies on the intrinsic conformational properties of non-ionic pyrrolysine in gas phase

B3LYP/6-31G(d,p) level of theory is used to carry out a detailed gas phase conformational analysis of non-ionized (neutral) pyrrolysine molecule about its nine internal back-bone torsional angles. A total of 13 minima are detected from potential energy surface exploration corresponding to the nine internal back-bone torsional angles. These minima are then subjected to full geometry optimization and vibrational frequency calculations at B3LYP/6-31++G(d,p) level. Characteristic intramolecular hydrogen bonds present in each conformer, their relative energies, theoretically predicted vibrational spectra, rotational constants and dipole moments are systematically reported. Single point calculations are carried out at B3LYP/6-311++G(d,p) and MP2/6-31++G(d,p) levels. Six types of intramolecular H-bonds, viz. O…H–O, N…H-O, O…H–N, N…H–N, O…H–C and N…H–C, are found to exist in the pyrrolysine conformers; all of which contribute to the stability of the conformers. The vibrational frequencies are found to shift invariably toward the lower side of frequency scale corresponding to the presence of intramolecular H-bond interactions in the conformers.     

New aromatic compounds from the rhizomes of Homalomena occulta

Three new aromatic compounds, identified as 1-(3′,4′-methylenedioxy-phenyl)-10-(3″-hydroxyphenyl)-decane (1), 1-(3′,4′-methylenedioxy-phenyl)-12-(3″-hydroxyphenyl)-dodecane (2), and 1-(3′,4′-methylenedioxy-phenyl)-12-(3″-hydroxyphenyl)-6Z-dodecylene (3), along with six known compounds (4–9) were isolated from the 95% EtOH extract of Homalomena occulta. Their structures were elucidated by chemical and spectral methods Compounds 4–9 were isolated for the first time from this plant. Compounds 1–3 exhibited inhibitory activity against BACE1, with IC₅₀ values of 0.82–1.09 μmol/L.     

Phospholipids of membranes of cultured cells and the products of protoplast fusion

The variety and distribution of phospholipids in the cell membranes of cultured cells and their fatty acid composition were analysed. Membranes of suspension cultured cells of Rauwolfia serpentina var. Bentham, Nicotiana tabacum var. Samsun, Atropa belladonna and Bouvardia ternifolia had almost the same composition of phosphatidylcholine, PC (ca 50%); phosphatidylethanolamine, PE (ca 25%); phosphatidylinositol, PI (ca 10%); phosphatidylglycerol, PG (several %); and phosphatidic acid, PA (several %). We determined the distribution of the molecular species of the three major phospholipid fractions (PC, PE and PI) in R.serpentina and N.tabacum. Membranes of both cell-types contained basically similar molecular species, 1–16:0/2–18:2 the main type, particularly in the PC- and PE- fractions; 1–18:2/2–18:2 and 1–18:0/2–18:2 for R. serpentina; and 1–16:0/2–18:3, 1-18:0/2-18:3 and 1-18:2/2-18:2 for N.tabacum. The influence of membrane fluidity on protoplast fusion as effected by the phase transition of the phospholipids, is discussed.     

Erythroid Elements of Hemolymph in Anadara kagoshimensis (Tokunaga, 1906) under Conditions of the Combined Action of Hypoxia and Hydrogen Sulfide Contamination

Russian Journal of Marine Biology - The effect of the combined action of hypoxia (0.05 mg O2/L) and hydrogen sulfide contamination (4–8 mg S2–/L) on the morphometric characteristics of...     

Theoretical investigations into the intermolecular hydrogen-bonding interactions of <Emphasis Type="Italic">N</Emphasis>-(hydroxymethyl)acetamide dimers

The structures of the N-(hydroxymethyl)acetamide (model molecule of ceramide) dimers have been fully optimized at B3LYP/6–311++G** level. The intermolecular hydrogen bonding interaction energies have been calculated using the B3LYP/6–311++G**, B3LYP/6–311++G(2df,2p), MP2(full)/6–311++G** and MP2(full)/6–311++G(2df,2p) methods, respectively. The results show that the O–H···O, N–H···O, O–H···N, and C–H···O hydrogen bonding interactions could exist in N-(hydroxymethyl)acetamide dimers, and the O–H···O, N–H···O, and O–H···N hydrogen bonding interactions could be stronger than C–H···O. The three-dimensional network structure formed by ceramide molecules through intermolecular hydrogen bonding interactions may be the main reason why the stratum corneum of skin could prevent foreign substances from entering our body, as is in accordance with the experimental results. The stability of hydrogen-bonding interactions follow the order of (a)?>?(b)?≈?(c)?>?(d)?>?(e)?≈?(f)?>?(g)?>?(h). The analyses of the energy decomposition, frequency, atoms in molecules (AIM), natural bond orbital (NBO), and electron density shift are used to further reveal the nature of the complex formation. In the range of 263.0–328.0 K, the complex is formed via an exothermic reaction, and the solvent with lower temperature and dielectric constant is favorable to this process.

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Graphical abstract The structures and the O–H···O=C, N–H···O=C and C–H···O=C H-bonding interactions in the N-(hydroxymethyl)acetamide (model molecule of ceramide) dimers were investigated using the B3LYP and MP2(full) methods.

     

Activation studies with amines and amino acids of the β-carbonic anhydrase from the pathogenic protozoan Leishmania donovani chagasi

The activation of a β-class carbonic anhydrase (CAs, EC 4.2.1.1) from Leishmania donovani chagasi (LdcCA) was investigated using a panel of natural and non-natural amino acids and amines. The most effective activators belonged to the amine class, with histamine, dopamine, serotonin, 2-pyridyl-methylamine and 4-(2-aminoethyl)-morpholine with activation constants in the range of 0.23–0.94 µM. In addition, 2-(2-aminoethyl)pyridine and 1-(aminoethyl)-piperazine were even more effective activators (K_As of 9–12 nM). Amino acids such as L-/D-His, L-/D-Phe, L-/D-DOPA, L-/D-Trp and L-/D-Tyr were slightly less effective activators compared to the amines, but showed activation constants in the low micromolar range (1.27–9.16 µM). Many of the investigated activators are autacoids that are present in rather high concentrations in different tissues of the host mammals infected by these parasites. As CA activators have not yet been investigated for protozoan CAs, this study may be relevant for an improved understanding of the role of this enzyme in the life cycle of Leishmania.     

A comparative theoretical study on the electrical and nonlinear optical properties of Li atom adsorbed on AlN and BN single-walled nanotubes

The geometrical structures, electrical properties, and nonlinear optical (NLO) properties of AlNNT–Li and BNNT–Li nanotube systems were investigated by means of the density functional theory (DFT) method. Frontier molecular orbitals and density of states analyses show that adsorption of the Li atom can significantly narrow the wide HOMO–LUMO gaps of pure AlNNT and BNNT. The results reveal that AlNNT–Li and BNNT–Li systems containing diffuse excess electrons can be regarded as inorganic electrides. The formation of diffuse excess electrons leads to a decrease in transition energies, thereby increasing the first hyperpolarizabilities (β ₀) of AlNNT–Li and BNNT–Li. This work may contribute to the development of potential high-performance NLO materials.

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Graphical abstract The structural characteristics and nonlinear optical properties of the AlNNT–Li and BNNT–Li systems were studied by means of density functional theory. Introduction of Li atoms greatly enhances the static first hyperpolarizabilities of AlNNT–Li and BNNT–Li

     

Antitumor immunotherapy with the use of synthetic fragments of survivin

The endogenous protein survivin is present in tumor cells and inhibits apoptosis. The influence of vaccination of mice by survivin fragments on growth of various types of tumors was studied in order to examine the possibility of creation of an antitumor vaccinating agent on its basis. Two peptides corresponding to the 118–144 and (80–88)-(153–165) sequences of survivin 2B were chosen and synthesized on the basis of literature data and theoretical calculations. Their ability to stimulate antibody production in mice of the C57BL/6J line (b-haplotype) and in BDF1 hybrids (b × d-haplotype) was investigated. Both peptides were shown to stimulate production of antibodies that bound the recombinant survivin in the BDF1 mice. Immunization of BDF1 and C57BL/6J mice with the recombinant survivin resulted in formation of antibodies that reacted with 118–144 peptide. The effect of preventive vaccination with the peptides and the recombinant protein on dynamics of growth of several species of tumors was studied. Vaccination with the (80–88)-(153–165) peptide was found to cause an antitumor effect in BDF1 mice suffered from sarcoma S-37. Thus, creation of antitumor agent on the basis of this peptide is a promising area of further studies.