Proton motive force in washed cells of Rhizobium japonicum and bacteroids from Glycine max.

The components of the proton motive force (delta p), namely the membrane potential and the transmembrane pH gradient, were measured in washed cells of Rhizobium japonicum CC705 grown in cultures (5% O2-95% N2) in the presence of 10 mM KNO3 and in bacteroids from Glycine max. The delta p and its components remained reasonably constant in cells as well as in bacteroids at various stages of growth. The effects of uncouplers and ATPase inhibitors on the delta p and its components were determined in both cultured cells and bacteroids. The data indicated that a respiration-driven H+ translocation is the source of the delta p in both cultured cells and bacteroids.     

Kinetic studies of corn stover saccharification using sulphuric acid

The kinetics of crystalline cellulose and hemicellulose hydrolysis in corn stover were studied with a nonisothermal technique. Reactions were arrested at temperatures between 160 and 240 degrees C and product sugars were analyzed using a Bio-Rad HPX-85 liquid chromatographic column. A simple first-order series reaction model was used for both cellulose and hemicellulose hydrolysis reactions. Kinetic parameters were obtained for three different sulphuric acid concentrations (0.49, 0.92, and 1.47 wt %). Activation energies remained constant over this acid concentration range but the preexponential factors showed an increase with acid concentration. Relationships were obtained between the preexponential factors and acid concentrations. Cellulose hydrolysis and glucose degradation reactions were observed to be of higher order with respect to acid concentration in comparison with the previous studies with other raw materials.     

Glyburide action in cultured 3T3-L1 adipocytes

During adipocyte differentiation of 3T3-L1 cells, glyburide increased the specific activity (mU/mg protein) of glycerol-3-P dehydrogenase (by at least 14-fold) and glutamine synthetase (by 5-fold). The glyburide-mediated increases in enzyme activities were greater in the presence than in the absence of insulin. Our data indicate that glyburide either potentiates or mimics the actions of insulin to increase the activity of glycerol-3-P dehydrogenase during adipocyte differentiation of cultured 3T3-L1 cells.     

Effects of nutritional deficiencies during neonatal and post-weaning period on rat intestinal phytase and phosphatase activities

Studies were made of the effects of pre- and post-weaning undernutrition and/or protein deficiency on intestinal phytase and phosphatase activities in albino rats and reversibility of the same by subsequent dietary rehabilitation. Neonatal undernutrition induced by rearing the pups in litters of 16 caused a marked decrease in alkaline phytase activity (as compared to those reared in litters of 8), while acid phytase activity decreased to a lesser extent and acid and alkaline phosphatase activities did not change. When neonatally undernourished rats were subsequently continued on a 4 or a 20% protein diet in restricted amounts (2.5 g/day) for 6 weeks the decreases in the alkaline phytase activity but not in that of acid phytase were further aggravated. Acid and alkaline phosphatases were not influenced by these treatments either. On dietary rehabilitation of these rats for subsequent 6 weeks on a 20% protein diet (ad libitum) acid and alkaline phytase activities of intestine recovered partially. These studies indicate the importance of alkaline phytase activity as a marker of intestinal maturation and is also suggestive of interrelationships between nutrition, intestinal development and its alkaline phytase activity.     

STUDIES IN THE VISCACEAE. II. A REINVESTIGATION OF THE FEMALE GAMETOPHYTE OF ARCEUTHOBIUM DOUGLASII

A reinvestigation of the female gametophyte of Arceuthobium douglasii showed that the development conforms to the Allium type (bisporic), and the report of tetrasporic development is erroneous.     

üBisch Granules on Tapetal Membranes in Anthers; Rapid Selective Staining by Spirit Blue

Decapitate the anther and squeeze out its contents into a drop of water on a clean slide coated with Haupt's adhesive. Let slides air dry and stain the preparations for 4-6 hr in 0.005% spirit-soluble aniline blue, prepared in 50% ethanol. Pass the slides through acetone, 10 min; 1:1 mixture of acetone and xylene, 5 min; and xylene. Mount in a resinous medium. The technique is effective for both fresh anthers and anthers fixed in FAA, Carnoy's fluid, 1:3 acetic alcohol, and 10% formalin (commercial). For fixed anthers, follow customary methods of paraffin embedding and microtomy.     

Response of barley and wheat to phosphorus in the presence of chloride and sulphate salinity

Summary The study was conducted in a greenhouse and under field conditions. In the greenoouse, barley was grown to maturity in pots on a sandy soil which contained 80 and 120 meq/l of chloride and sulphate dominant salts in its saturation extract, to which 0, 10, 25 and 50 ppm P were added. In the field study, wheat was grown on loamy sand soils having 0, 25, 50 and 75 kg/ha added P levels and irrigated with either Cl- or SO₄-dominant saline waters (EC=15–19 mmhos/cm). The results of the greenhouse study indicated that at maturity barley straw and grain yield was significantly increased by 50 ppm of added P both on the non-saline control and the Cl-treatments. However, 25 ppm P was optimal on the SO₄-treatments. The Cl content of plants was significantly decreased and S was increased with the increase in the P content of soil. A synergistic relation between the S and P content of barley shoots was observed. In the field study wheat grain yield responded significantly to P applications upto 50 kg/ha level on the Cl-site and there was no response to applied P on the SO₄-site, although the former contained more Olsen's P than the latter. The results suggested that P requirement of wheat and barley was greater on Cl- than on SO₄-salinity.     

Preparation of membrane vesicles in lithium chloride from cells of Nitrosomonas europaea

The preparation of membrane vesicles in lithium chloride is described which oxidizes NH₄Cl via hydroxylamine to nitrite. The following properties of the vesicles were determined: the uptake of NH₄Cl and O₂ by electrode methods, the production of NH₂OH and NO₂ from NH₄Cl as well as ATPase activity. The stoichiometry of NH₄⁺:O₂:NO₂^? was found to be 1:1.2:0.7 in vesicles compared with 1:1.5:1.0 in either spheroplasts or washed cells. It is shown that the membrane vesicles also contain a Cu and energy-dependent NH₄^? translocase as in spheroplasts and cells.     

Okadaic acid-mediated induction of the c-fos gene in estrogen receptor-negative human breast carcinoma cells utilized, in part, posttranscriptional mechanisms involving adenosine-uridine-rich elements.

Signal transduction via modulation of phosphorylation after selective inhibition of protein phosphatase (PP) 1 and/or PP2A appears to play a role in okadaic acid (OA)-mediated effects. Treatment of several estrogen receptor-negative human breast carcinoma (HBC) cells with 100 nM OA resulted in induction of c-fos, c-myc, and cyclin-dependent kinase inhibitor p21WAF1/CIP1 genes. Transfections of various luciferase reporter constructs in HBC cells revealed involvement of activator protein-1-dependent as well as -independent pathways in induction of the c-fos gene by OA. MDA-MB-468 HBC cells were stably transfected with plasmids expressing luciferase, chimeric luciferase- c-fos 3' untranslated region (3'UTR), or chimeric luciferase-p21WAF1/CIP 3'UTR mRNAs. Expression of chimeric luciferase-c-fos and luciferase-p21WAF1/CIP1 mRNAs was elevated by OA in several independent sublines. Actinomycin D chase experiments revealed an enhanced rate of decay of luciferase-c-fos mRNA, whereas treatment with OA caused approximately 3.5-fold enhanced stability of the chimeric luciferase-c-fos mRNA only. By transfecting different plasmids containing deletions of c-fos 3'UTR, OA-responsive sequences were mapped to an 86-nucleotide, AU-rich region. UV cross-linking experiments using HBC cell cytosolic proteins showed multiple complexes with the AU-rich region subfragments of c-fos, as well as c-myc and p21WAF1/CIP1 mRNAs. OA enhanced binding of a novel Mr approximately 75,000 protein present in the cytosolic extracts of HBC cells to the AU-rich RNA probes of all of the above three genes. Taken together, OA regulation of HBC cell gene expression involves the activator protein-1 pathway, as well as enhanced binding of a novel Mr approximately 75,000 protein to an AU-rich region of the 3'UTRs of the target genes.