Combined use of COSY and double quantum two-dimensional NMR spectroscopy for elucidation of spin systems in polymyxin B

Two-dimensional single quantum correlation NMR spectroscopy (COSY) and two-dimensional double quantum NMR spectroscopy (2QT) are used to study spin systems in the 1H NMR spectrum of polymyxin B. Because of different frequency relationships, the two types of two-dimensional NMR experiments are found to be highly complementary. This is demonstrated by combined use of COSY and 2QT spectroscopy to obtain a complete analysis of the complicated spectral overlap which occurs in the 1H NMR spectrum of polymyxin B.     

Bacterial flora of the root surface of wheat grown in nutrient solutions deficient in nitrogen and phosphorus

Изучался состав бактериальной флоры поверхности корней пшеницы, выращиваемой в питательном растворе Кнопа—как с полным составом питательных веществ, так и при отсутствии азота и фосфора. Недостаток азота заметно отражался на росте растений и на составе бактериальной флоры: отмечено понижение встречаемости менее требовательных к питанию бактерий и повышение числа бактерий, требующих питательных веществ, содержащихся в дрожжевом и почвенном экстрактах —при понижении встречаемости быстро растущих типов. Не было отмечено разницы в составе бактериальной флоры поверхности корней пшеницы, выращиваемой в питательном растворе полного состава—или же в среде, лишенной фосфора.      

Microsomal and cytosolic cytochrome P450 mediated benzo(a)pyrene hydroxylation in Pleurotus pulmonarius

Summary Microsomal and soluble fractions of Pleurotus pulmonarius exhibited a reduced carbon monoxide difference spectrum with P450 maxima at 448nm and 450–452nm respectively. Substrate induced Type I spectra were observed on addition of benzo(a)pyrene to both fractions. Benzo(a)pyrene hydroxylation was measured using the aryl hydrocarbon hydroxylase assay and was observed to be P450 dependent as indicated by carbon monoxide inhibition together with the substrate binding characteristics. The activity of the fractions were observed to give K_m of 200mM and 660mM and V_max of 1.25 nmol/min/nmol P450 and 0.57 nmol/min/nmol P450 for the microsomal and cytosolic fractions respectively.     

Biological decomposition of fulvic acid preparations

Decomposition of preparations of various fractions of fulvio acids in pure cultures of bacteria and in the soil was investigated. In the soils enriched with fulvic acids the amount of bacteria increased, oxygen consumption and formation of carbon dioxide followed a typical sigmoid curve. The above measurements indicated that mineralization occurred after a very short or negligible lag phase. During the decomposition of fulvic acids the ability of microorganisms to oxidize aromatic compounds,e.g. vanillio andphydroxybenzoic acid, increased. The presence of aromatic structures in the used preparations of fulvic acids was demonstrated on the basis of their IR spectra and according to the results of Chromatographic analyses of their hydrolysates. The results indicated a relationship between metabolism offulvio acids and aromatic oompounds. In samples of the soil preincubated with glucose the fulvic acids decomposed more rapidly than in untreated samples.     

Methylated DNA/RNA in Body Fluids as Biomarkers for Lung Cancer

DNA/RNA methylation plays an important role in lung cancer initiation and progression. Liquid biopsy makes use of cells, nucleotides and proteins released from tumor cells into body fluids to help with cancer diagnosis and prognosis. Methylation of circulating tumor DNA (ctDNA) has gained increasing attention as biomarkers for lung cancer. Here we briefly introduce the biological basis and detection method of ctDNA methylation, and review various applications of methylated DNA in body fluids in lung cancer screening, diagnosis, prognosis, monitoring and treatment prediction. We also discuss the emerging role of RNA methylation as biomarkers for cancer.     

Effect of glucose on the decomposition of organic materials added to soil

The effect of glucose on the decomposition of plant material in soil was studied. Soil samples were enriched with different fractions of labelled alfalfa: the soluble dialyzable fraction, the soluble nondialyzable fraction, cellulose-lignin, lucerne meal. The added substances were decomposed for 42 days. One soil sample in every experimental variant was then percolated with water and another with 200 ml. 0.5% glucose for another 21 days. It was found that the effect of glucose on decomposition of the plant material depended on the latter’s composition and degree of decomposition. It was small in soils pre-enriched with soluble alfalfa fractions, decomposition of which was largely completed within the given time. Glucose markedly inhibited the release of radioactive carbon from the celluloselignin fraction and stimulated the formation of radioactive carbon dioxide from alfalfa meal.     

The development ofAzotobacter in the oat rhizosphere and its effect on the yield

ИccлeДOBAлocь paэBиTиe paэлиЧHьix Πitammb aэotoбaкtepa b pиэocфepe obca и иx bлияhиe ha ypoжa и. ΠepbohaЧaлЧhЧie Πitammьi cpabhиbaлиcь c t. h. iiaccaж иpobahhьimh шtammamи (te жe шtammьi, Aotopьie длиte иьho пobtopho bьipaщиba лиcь B pиэOCфepe OBca, pocшe гo B CTepилиэoBaHHoй Π). БaкTepиэaция ceMяB OBca BceMи шTaMMaMи aэOTOбaкTepa Bлиялa лa Ha кOлиЧecTBO aэOToбaкTepa B ΠOЧBe PиэOCъepьI, HO He Ha кOPHяX. Πaccaжи aэOTOбaкTepa Чepeэ pиэocфepy OBca B HaшиX ycлoBияX OΠьITa He yBeлиЧиBaли CΠOCOбHOCTи эTиX шTaMMOB paэBиBaTьCя бOлee yCилeHHO Ha кOPHяX или B ΠOЧBe PиэOCфePяI, ЧeM пePBOHaЧaлпHпIe шTaMMьI, — B OTлиЧиe OT дaHHьIX OпьITOB CO шTaMMaMи aэOTOбaкTepa, кOTOPьIe BьIPaщиBaлиCь C AOPHяMи PaCTeHий B CPeдe C aг;apoM (эиHOBьeBa 1950‐1954, BaHЧypa C COTP. 1959). БaкTepиэaпия BCeMи шTaMMaMи aэOTOбaкTepa цOBяIшaлa ypoжaй B CPaBHeHии C кOHTpOлeM.