Induction of differentiation of cultured human promyelocytic leukemia cells by retinoids

Human promyelocytic leukemia cells (HL-60) were induced to phagocytize, reduce NBT dye(nitroblue tetrazolium), and change into forms that were morphologically similar to mature granulocytes by retinoic acid and related retinoids, but not by the pyridyl analog of retinoic acid. Induction of differentiation could be detected after 4 days of treatment of the cells with retinoic acid at as low a dose as 4 × 10^?8 M. Thus, retinoids may be used in studies on the control of cell differentiation and malignancy of human myeloid leukemia cells.     

Growth and cell wall changes in azuki bean epicotyls I. Changes in wall polysaccharides during intact growth

Measurement of endogenous growth rates and the mechanical propertyof the cell wall in various regions of light-grown azuki beanepicotyls revealed diat the minimum stress-relaxation time (T_o)was the shortest in the upper region (0–30 mm below theapex) of the epicotyl, where vigorous endogenous growth tookplace, and became longer toward the basal region, which wasmature and not growing. In the upper region of the epicotyl, a lower percentage of a-celluloseand a higher percentage of pectic substances than in the lowerregion were found. The percentage of hemicellulose content wasalmost constant over the whole epicotyl. Major components ofnoncellulosic neutral sugars in the cell wall were galactoseand xylose. The percentage of the galactose content to the noncellulosicpolysaccharide was highest in the upper region and lowest inthe basal region of the epicotyl, and a clearly negative correlationbetween the galactose composition and the T_o value was obtained.On the contrary, the percentage of die xylose content was highestin the basal region and lowest in die upper region, and a clearlypositive correlation between die xylose composition and theT_o value was obtained. During die endogenous growth of die intactepicotyl, all die neutral sugars, particularly galactose, increasedin die upper region, whereas in die middle and basal regions,only xylose increased. Similar changes in sugar compositionswere observed during IAA-induced elongation of die segment excisedfrom various regions of die epicotyl. (Received July 27, 1978; )     

Growth and cell wall changes in azuki bean epicotyls II. Changes in wall polysaccharides during auxininduced growth of excised segments

Changes in cell wall polysaccharides and mechanical propertiesof the cell wall were examined during IAA-induced elongationgrowth of excised azuki bean epicotyl segments under differentgrowth conditions. Sucrose promoted IAA-induced cell elongation,but had very little effect on IAA-induced cell wall loosening.In the absence of sucrose, the amount of galactose in the cellwall decreased during the incubation period. IAA enhanced thedecrease in the galactose level. In the presence of sucrose,on the other hand, IAA induced increases in the amounts of cellulose,galactose and xylose in noncellulosic polysaccharides. TheseIAA-induced increases were not observed in the presence of mannitolat concentrations higher than 0.1 M, although cell wall looseningwas induced by IAA even in the presence of 0.2 M mannitol. (Received November 21, 1978; )     

Stress sensitive glucose oxidase-nylon membrane

Summary Glucose oxidase (GOD) was immobilized on a nylon membrane. No activity of the GOD-nylon membrane was observed under normal conditions but it appeared when the membrane was mechanically stretched. A linear relationship was observed between the stress strength and the GOD activity of the membrane. The appearance of the GOD activity of the membrane with stress was reproducible and the membrane could be stored for at least 2 months. Therefore, the GOD-nylon membrane can be called a stress sensitive membrane.     

Mean and variance of FST in a finite number of incompletely isolated populations

In the presence of migration F_ST in a finite number of incompletely isolated populations first increases, but after reaching a certain maximum value, it starts to decline and eventually becomes 0. The mean and variance of F_ST in this process are studied by using the recurrence formulas for the moments of gene frequencies in the island model of finite size as well as by using Monte Carlo simulation. The mean and variance in the early generations can be predicted by the approximate formulas developed. On the other hand, if we exclude the cases of an allele being fixed in all subpopulations, the mean of F_ST eventually reaches a steady-state value. This value is given by 1 − 2N_T(1 − λ) approximately, where N_T is the total population size and λ is the rate of decay of heterozygosity at steady state. It is shown that the mean and variance of F_ST depend on the initial gene frequency and when this is close to 0 or 1, Lewontin and Krakauer's test of the neutrality of polymorphic genes is not valid.     

Effect of indole-3-acetic acid on cell wall loosening: Changes in mechanical properties and noncellulosic glucose content of Avena coleoptile cell wall

The effect of indole-3-acetic acid on cell wall loosening andchemical modifications of noncellulosic components of the cellwall in Avena coleoptile segments was studied and the followingresults were obtained. (1) Auxin decreased both the minimum stress-relaxation time(T_o) and the noncellulosic glucose content of the cell wall. (2) Decreases were observed in the absence or presence of mannitolsolution at concentrations lower than 0.20 M which osmoticallysuppressed auxin-induced extension, while at concentrationshigher than 0.25 M, there was little auxin effect, indicatingthat it is turgor-dependent. (3) The decrease in T_o of the cell wall and that in the noncellulosicglucose content caused by auxin in the presence of mannitolsolutions of various concentrations paralleled each other (thecorrelation coefficient was 0.897). (4) Both decreases in T_o and glucose content caused by auxinwere inhibited by nojirimycin (5-amino-5-deoxy-D-glucopyranose)in the presence of mannitol. The results suggest that auxin-induced cell wall loosening iscaused by the degradation of noncellulosic rß-glucanin the cell wall. (Received December 24, 1976; )     

Role of lipopolysaccharide and outer membrane protein of Escherichia coli K-12 in the receptor activity for bacteriophage T4.

Lipopolysaccharide isolated from Escherichia coli K-12 did not inactivate phage T4, although the cell envelopes with 1% sodium deoxycholate resulted in the release of cytoplasmic membrane proteins, 70% of the lipopolysaccharide, and almost all of the phospholipid. The reconstitution of phage receptor activity was achieved from deoxycholate-soluble and -insoluble fractions by dialysis against a solution of magnesium chloride. Lipopolysaccharide was the only essential component in the deoxycholate-soluble fraction. PhageT4-resistant mutants YA21-6 and YA21-82, having defects in the deoxycholate-soluble and -insoluble fractions, respectively, were isolated. The deoxycholate-soluble fraction of YA21-6 possessed heptoseless lipopolysaccharide, and this defect was responsible for the phage resistance. The deoxycholate-insoluble fraction of YA21-82 lacked outer membrane protein O-8. The addition of O-8 to this fraction together with the wild-type lipopolysaccharide resulted in the appearance of the receptor activity. Furthermore, the reconstitution was successfully achieved with only O-8 and the wild-type lipopolysaccharide, indicating that O-8 was an essential component in the deoxycholate-insoluble fraction.     

Abscisic acid from Pinus densiflora pollen

(+)-Abscisic acid was isolated as the methyl ester from Pinus densiflora pollen and identified spectroscopically.     

Novel p-coumaric acid esters from Pinus densiflora pollen

Solvent-extractable lipids in Pinus densiflora pollen were investigated. The cis- and trans-isomers of 1,16-dioxo-, 1-hydroxy-16-oxo- and 1, 16-dihydroxyhexadecan-7-yl p-coumarates were identified.