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At least 1,153 records · Page 64Linked to original sources
PubMed1975

[New tetraene antibiotic, abkhazomycin].

The cultures of Act. L10-0740 and L10-0772 were isolated from a soil sample. By their morphological and cultural features they were close to Act. badiocolor and differed from the latter by their antibiotic properties. Because of this they were classified as a new variant of Act. badiocolor var. abhasus var. nov. The cultures produced a new tetraen antibiotic, named abkhazomycin. Its physico-chemical properties are presented.

Actinomyces↗
PubMed1975

[Variability of the levorin producer, Actinomyces levoris Krass].

Natural variation of the levorin-producing organism Act. levoris, strain 28 was studied with respect to the colony morphology and production of levorin and levoristatin. The population of strain 28 consisted of 3 morphological colony types, the main type amounting to 99.7 percent. The strain variation with respect to production of levorin and levoristatin ranged from 20 to 180 and from 0 to 300 percent respectively as compared to the control. Mutant M-28 differing from the initial strain by the colony morphology, moderate phage titer and preferable production of levoristatin was isolated as a result of repeated passages of strain 28 onto agarized Chapek media with starch without maintaining selection. Variants differing from the population of strains 28 and M-28 by the ratio of levorin and levoristatin in the culture fluid were selected. No correlation in production of the above antibiotics by strain 28 was noted. Preparations obtained with strain M-28 differed from those obtained with strain 28 in a significant content of levoristatin.

Actinomyces↗
PubMed2002

The separation of hypericine and pseudohypericine from Hypericum perforatum L.

The extraction of Hypericum perforatum L. was carried out by the method of ultrasonic maceration. The separation of H. perforatum L. extract in order to obtain hypericine and pseudohypericine rich fractions was carried out by the following chromatographic methods: flash column chromatography, high speed countercurrent chromatography, XAD solid phase extraction and Sephadex column chromatography. The separation by the Sephadex column chromatography gave the best results. Preparative HPLC was used to isolate hypericine and pseudohypericine from fraction 4 obtained by the Sephadex column chromatography procedure.

Anthracenes↗
PubMed1975

Effect of isolated head heating and cooling on sweating in man.

A double climate chamber which permitted the independent regulation of temperature in each chamber was used to produce isolated head heating and cooling in three subjects. Deep body temperature was recorded from the tympanic membrane, oral cavity, esophagus, and rectum. Skin temperature was measured on nine body regions and a weighted mean skin temperature was calculated. Sweating rate was measured by resistance hygrometry from six regions. When head skin temperature was increased, deep body temperature measured at the tympanic membrane and oral cavity increased more than esophageal temperature, while rectal temperature remained essentially unchanged. Sweating rate increased when head skin temperature increased and again, somewhat later, as the tympanic membrane and oral temperatures began to rise. When head skin temperature was decreased, tympanic membrane and oral temperatures decreased and sweating again followed the changes in skin temperature as well as the changes in tympanic membrane and oral temperatures. Since it has been shown that head skin temperature is particularly important in determining thermal comfort and sweating rate when compared to other body regions, it is suggested that this particular sensitivity is in part due to a thermal counter-current exchange between venous blood draining the head and arterial blood ascending to intracranial thermoreceptors. Such an exchange would correspond to similar mechanisms present in other species.

Body Temperature↗
PubMed2001

[Separation of standard proteins and actual samples using cross-axis counter current chromatography].

A system of m (12.5% PEG8000): m (25% K2HPO4) = 1:1 was used to separate two kinds of standard proteins, glycoprotein in Morchella esculenta (L.) and glycoprotein in Lycium barbarum (L.), the upper phase was used as stationary phase, and the lower phase was used as mobile phase. The revolution speed was 500 r/min and the flow rate was 60 mL/h. In comparing with high performance liquid chromatography, cross-axis counter current chromatography can increase load capacity without loss of resolution. The advantage of this method was verified, indicating that cross-axis counter current chromatography was a useful method for biopolymer separation.

Ascomycota↗
PubMed2002

[Prediction of eluotropic sequence of solutes in countercurrent chromatography].

According to the retention equation of countercurrent chromatography (CCC), the eluotropic sequence of solutes depends mainly on the order of their partition coefficients between the two immiscible liquid phases. The varying tendencies of partition coefficients of some compounds in aqueous or non-aqueous solvent systems by calculating the phase equilibria with universal quasichemical functional group activity coefficient (UNIFAC) (Dortmund) model are predicted. These compounds included saturated and unsaturated fatty acids ethyl esters, N-2,4-dinitrophenylamino alcohols, p-nitrophenyl glucosides and so on, with simple structures and much differences in polarity. It has been found that the predicted tendencies of partition coefficients of the analogues were consistent with the experimental ones reported in literature, and the best results were obtained for saturated fatty acid ethyl esters in hexane-acetonitrile (1:1 in volume ratio) solvent system. The establishment of a method for prediction will be helpful for the selection of non-electrolyte solvent systems in CCC.

Countercurrent Distribution↗
PubMed2002

[Separation of eleutheroside E from crude extract of Radix Acanthopanacis Senticosus by analytical and preparative high-speed countercurrent chromatography].

Analytical high-speed countercurrent chromatography (HSCCC) was used for the systematic optimization of the two-phase solvent system to separate eleutheroside E from crude extract of Radix Acanthopanacis Senticosus. Eleutheroside E was obtained by preparative HSCCC with two-phase solvent system composed of chloroform-methanol-isopropanol-water (5:6:1:4 in volume ratio). The mobile phase is the lower phase and operated at a flow-rate of 2.0 mL/min, while the apparatus rotated at 800 r/min. High performance liquid chromatographic analysis of eleutheroside E revealed that its purity was over 98%. HSCCC is a useful method for the separation of natural products.

Countercurrent Distribution↗
PubMed2002

[Cell interaction with extracellular proteins during two-phase polymer system formation].

A modified method of investigation of surface properties of cells and proteins with the help of a two-phase polymer system dextran-500/polyethylenglycol-6000 was used. This method is based on changing the kinetics of two-phase system partitioning into phase on adding cells or macromolecules. These changes were registered by measuring the top phase optical density during the system partitioning at 500 nm. Cell lines L (NCTC clone 929), LS and A431, human keratinocytes and platelets, collagen I, laminin-1, laminin-2/4, and fibronectin were studied. The interaction between collagen and all cell types with the formation of complexes takes place during co-partitioning of cells and proteins in the two-phase system. Laminins differ in surface properties and in interaction with cells. Laminin-1 makes preferable complexes with cells of monolayer subline L (NCTC clone 929), but not with cells of suspension subline LS. No interaction of laminin-2/4 with L cells was detected, but, in contrast to laminin-1, this protein has the affinity to A431 cells. No interaction of L cells with fibronectin were detected.

Animals↗