Glycosphingolipids of the globo-series are associated with the monocytic lineage of human myeloid cells

Neutral glycosphingolipids (neutral GSLs) of the human myeloid leukemia cell lines ML-2, ML-3, HL-60 and THP-1-0 were metabolically labeled with [3H]galactose and [3H]glucosamine, and analyzed by high-performance liquid chromatography. They were compared with unlabeled neutral GSLs from purified human granulocytes and monocytes. Neutral GSLs were identified by retention times and the structures were further confirmed by degradation with specific exoglycosidases. Two neutral GSLs of the globoseries, globotetraosylceramide and globotriaosylceramide were found in monocytes and the monoblastic leukemia line THP-1-0. The leukemia-derived cell-lines, ML-3 and HL-60, representing successively earlier stages of myeloid differentiation, contained respectively less neutral GSLs of the globoseries and an increasing proportion of (neo)lacto neutral GSLs. Granulocytes and the cell line ML-2 contained almost exclusively neutral GSLs of the (neo)lacto series.     

Structural and chemical characterization of S-layers of selected strains ofBacillus stearothermophilus andDesulfotomaculum nigrificans

The structures, amino acid- and neutral sugar compositions of the crystalline surface layers (S-layers) of four selected strains each ofBacillus stearothermophilus andDesulfotomaculum nigrificans were compared. Among the four strains of each species a remarkable diversity in the molecular weights of the S-layer subunits and in the geometry and constants of the S-layer lattices was apparent. The crystalline arrays included hexagonal (p6), square (p4) and oblique (p2) lattices. In vitro self-assembly of isolated S-layer subunits (or S-layer fragments) led to the formation of flat sheets or open-ended cylindrical assembly products. The amino acid composition of the S-layers exhibited great similarities and was predominantly acidic. With the exception of the S-layers of two strains ofB. stearothermophilus (where only traces of neutral sugars could be detected), all other S-layer proteins seemed to be glycosylated. Among these strains significant differences in the amount and composition of the glycan portions were found. Based on this diversity interesting questions may be asked about the biological significance of the carbohydrate units of glycoproteins in prokaryotic organisms.     

An inverse problem in neural processing

Any neural network aimed at the coding sensory events must contain computational properties which generally allow the organism to reconstruct the input signals with some degree of accuracy-else the association between stimulus and response would, at best, be uncertain. In this paper we investigate the problem of reconstructing external input signals to neural networks when the activity profiles of only some of its member cells are known. The evolution and activities of such cells are defined by an earlier formulation of one of us (Ouztöreli 1979) and, here, we restrict our application to local curcuits within the vertebrate retina. Solutions to this inverse coding problem are presented for specific network equations and examplified with 1, 3, and 5 neuron cases.This work was partially supported by the Natural Sciences and Engineering Research Council of Canada under Grant A-4345 to M.N.O. and grant A-4395 to T.M.C. through the University of Alberta     

Control mechanisms of a neural network

In this paper we consider some classical control theoretic properties of a nonlinear neural network proposed by Ouztöreli (1979) to represent the activities of constiuent neurones in terms of the input signals and coupling (associative) properties. By breaking the network into linear and nonlinear components we have been able to localize the nonlinearities in the individual neural response latencies through the system.This work was partially supported by the Natural Sciences and Engineering Research Council of Canada by Grant NSERC-A 4345 to M.N.O. and Grant NSERC-A 2568 to T.M.C. through the University of Alberta     

The comparison of seed protein patterns within the genusArachis by polyacrylamide gel electrophoresis

The seed protein patterns of 12Arachis species were compared by polyacrylamide gel electrophoresis (PAGE), similarities between patterns were measured by the Jaccard index. Results obtained confirm the close relationships established between members of the genus on morphological grounds and support the more recent classification schemes.A. villosa andA. correntina could well be regarded as distinct species on grounds of protein differences whileA. macedoi andA. villosulicarpa (although members of the same section, Extranervosae) show considerable differentiation of their protein patterns. Surprisingly, the formA. ×batizogaea showed less similarity in protein pattern to those of its parental species than might have been expected. The principle value of seed protein pattern data appears to be in distinguishing species within sections.     

Flavonoids from Rhamnus pallasii

A new dihydroflavonol, pallasiin, together with kaempferol, quercetin, isorhamnetin, mearnsetin, aromadendrin, eriodictyol and taxifolin, has been isolated from the bark of Rhamnus pallasii and its structure elucidated as 2,3-dihydromyricetin 4′-O-methyl ether.     

Study of the effect of volatile substances from cereal roots

We traced the liberation and biological effect of volatile substances released from the roots of cereals,i. e. barley, wheat, rye and oats, on seedlings of the same and other plant species. Experiments were carried out in a closed glass apparatus with a static or circulating atmosphere in which the CO₂ and O₂ were permanently absorbed and supplemented, respectively. In some experiments the air was bubbled through water or through solutions of boric acid, barium hydroxide and potassium permanganate. The roots of all four cereals tested released volatile substances with a biological activity which appeared to be non-specific with respect to plant species. The effect of volatile substances was partially decreased by bubbling through water, barium hydroxide and boric acid and was completely removed after passing through the solution of potassium permanganate. Volatile substances liberated from roots of barley inhibited elongation of roots and coleoptile, decreased SH-group content and caused excessive formation of root hairs as well as inhibition of both dry matter production and respiration of roots of rye seedlings. Ethylene was found in the atmosphere of experimental vessels.     

Electrophoretic investigation of proteins in different root zones ofvicia faba L.

The differentiation of tissues is closely connected with the proteosynthesis. One can therfore assume that tissues with different types of cell growth (meristematic or elongation growth) and with different degrees of differentiation are different in their protein composition. In order to compare the protein composition of different plant organs, the method of disc electrophoresis on a polyacrylamide gel has been used by some authors. As compared with other methods used up to now, e. g. isolating proteins on DEAE cellulose or in Sephadex, this method does not need so much material and its resolution ability seems to be higher. It is also quicker and enables the study of several samples simultaneously. Its disadvantage is that proteins can be identified mainly by means of Rf and their quantity, measured from the intensity of staining of individual fractions in the gel, which may be misleading due to different sorption capacity of different proteins (Fri?Fri?ová 1967). None the less, it is good for comparison of protein composition of individual parts of the plant body. Different methods have been used to compare protein composition of individual growth zones in roots.Barsky,Ivanov andPushakova (1965) used luminiscence microscopy and found that in maize roots it is not possible to find substantial differences by this method.Morgan andReith (1954) arrived at similar conclusions. On the other hand,Steward et al. (1965) andMorris (1966) found qualitative differences in protein composition of different parts of pea roots using acrylamide electrophoresis. The results of the last named authors show considerable discrepancies in details, due perhaps to a different method of extraction (buffer, pH, purifying method). We have used acrylamide gel electrophoresis for investigating proteins in precisely defined growth zones of theVicia faba root.     

Alternation of respiratory pathways during the development of wheat leaf

P?i vývoji listu p?enice se zmen?uje stupeň inhibice dýchání fluoridem, monojodacetátem a malonátem a poměr mezi radioaktivitami¹⁴CO₂ uvolněného z glukosy-6-¹⁴C a glukosy-l-¹⁴C (C₆/C₁), co? svěd?í o zvět?ování podílu pentosovího cyklu v celkové respiraci. Tato změna v?ak neni zp?sobena absolutním zvět?ením aktivity pentosového eyklu u star?ích list?, nýbr? p?edev?ím poklesem aktivity glykolytického systému. Naproti tomu u list? oddělených od obilky se pri sní?ení vlhkosti atmosféry méní poměr mezi dýchacími cestami v d?sledku aktivace pentosového cyklu. Na základě disproporce mezi procentem glykolytického podílu respirace vypo?tenym ze sní?ení poměru C₆/C₁ p?i inhibici dýchání fluoridem a procentem inhibice dý chání fluoridem bylo diskutováno o mo?ných p?íoinách vysokých poměr? C₆/C₁ u mladých list?, u nich? byly v některých p?ípadech zji?těny hodnoty těchto poměr? dokonce vy??í ne? jedna.