Selenium availability in berseem (Trifolium alexandrinum) as affected by selenium and phosphorus application

Summary The effect of selenium and phosphorus application on Berseem (Trifolium alexandrium) was studied in the green house. Each dose of selenium from O to 16 ppm decreased the dry matter yield of Berseem significantly at all the levels of applied phosphorus. Phosphorus stimulated the dry matter yield at all levels of selenium. Yields in the second cutting were of a higher order than in the first cut. Selenium application increased selenium and phosphorus content in Berseem, but at 8 and 16 ppm of selenium the phosphorus content decreased significantly. Sulphur concentration decreased with selenium application but application of phosphorus increased sulphur concentration showing synergetic effect.Studies on residual effect of selenium revealed that the application of 50 ppm of phosphorus increased the yield while that of 100 ppm decreased it. Selenium concentration which increased with increasing phosphorus was many fold higher in the first cutting than in the second cutting and similar was the trend with phosphorus and sulphur.     

Physical aspects and cytoplasmic distribution of messenger RNA in mouse kidney.

As a prerequisite to examining mRNA metabolism in compensatory renal hypertrophy, polyadenylated RNA has been purified from normal mouse kidney polysomal RNA by selection on oligo(dT)-cellulose. Poly(A)-containing RNA dissociated from polysomes by treatment with 10 mM EDTA and sedimented heterogeneously in dodecyl sulfate-containing sucrose density gradients with a mean sedimentation coefficient of 20 S. Poly(A) derived from this RNA migrated at the rate of 6-7 S RNA in dodecyl sulfate-containing 10% polyacrylamide gels. Coelectrophoresis of poly(A) labeled for 90 min with poly(A) labeled for 24 h indicated the long-term labeled poly(A) migrated faster than pulse-labeled material. Twenty percent of the cytoplasmic poly(A)-containing mRNA was not associated with the polysomes, but sedimented in the 40-80 S region (post-polysomal). Messenger RNA from the post-polysomal region had sedimentation properties similar to those of mRNA prepared from polysomes indicating post-polysomal mRNA was not degraded polysomal mRNA. Preliminary labeling experiments indicated a rapid equilibration of radioactivity between the polysomal and post-polysomal mRNA populations, suggesting the post-polysomal mRNA may consist of mRNA in transit to the polysomes.     

GANGLIOSIDES OF PERIPHERAL NERVE MYELIN

—Gangliosides have been isolated from myelin obtained from three types of peripheral nerve: bovine spinal roots, bovine sciatic nerve and human sciatic nerve. Yields in most cases were 218–287 μg of lipid-bound sialic acid per g myelin, less than half that previously obtained from CNS myelin. Myelin accounted for approx 60% of total ganglioside present in whole spinal root. The human sample contained only N-acetylneuraminic acid but the two bovine preparations contained that as well as N-glycolylneuraminic acid; N-acetylglucosamine and N-acetylgalactosamine were both present in all three preparations. Sphingosine was the major long-chain base in each preparation while 4-eicosasphingenine (d20:1) comprised about 14% in the two bovine samples and 3% in the human sample. The major fatty acids in all preparations were 16:0, 18:0, 22:0, 24:0 and 24:1. Sialosylgalactosyl ceramide (G₇), a ganglioside characteristic of CNS myelin, was not detected in any of the PNS samples. The majority of gangliosides in bovine spinal root myelin were monosialo species, although the structures differed in some respects from those of CNS myelin. The molar concentration of lipid-bound sialic acid in PNS myelin is roughly equivalent to that of the P₁ basic protein.     

9-Isoleucine]ACTH1-24, a competitive antagonist of ACTH1-24 induced cyclic AMP and corticosterone production.

Substitution of tryptophan⁹ in ACTH_1–24 by isoleucine results in complete loss of biological activity. A dose of 3.4 × 10^?5 M per ml fails to stimulate corticosterone and cyclic AMP production. This analogue inhibits cyclic AMP production and corticosterone production induced by ACTH_1–24 in isolated adrenal cortex cells. The I₅₀ values for corticosterone and cyclic AMP inhibition are 2.3 × 10^?6 M and 3.4 × 10^?6 M respectively.     

Messenger ribonucleoprotein complexes isolated with oligo(dT)-cellulose chromatography from kidney polysomes

As an initial step towards understanding the role of mRNP complexes in translational regulation during compensatory renal hypertrophy, characteristics of polysome-associated mRNP isolated by affinity chromatography were studied. Renal mRNP contained 15–30% of the counts after a 1 hr pulse with ³H-orotic acid; it sedimented mainly between 10S and 100S and had a buoyant density of 1.42–1.44 g/cm³. RNA derived from the mRNP sedimented between 5S and 40S on sucrose density gradients, with the greatest radioactivity in the region of 15S. After labeling with ³H-adenine for 1 hr, up to 17% of the radioactivity present in the mRNP-associated RNA was resistant to digestion by pancreatic and T1 ribonucleases. The mRNP protein moiety contained six polypeptides with molecular weights 69,000, 75,000, 80,000, 100,000, 109,000, and 118,000 daltons, which were undetected in the material not binding to oligo(dT)-cellulose.     

Daboxin P,a Major Phospholipase A2 Enzyme from the Indian Daboia russelii russelii Venom Targets Factor X and Factor Xa for Its Anticoagulant Activity

In the present study a major protein has been purified from the venom of Indian Daboia russelii russelii using gel filtration, ion exchange and Rp-HPLC techniques. The purified protein, named daboxin P accounts for ~24% of the total protein of the crude venom and has a molecular mass of 13.597 kDa. It exhibits strong anticoagulant and phospholipase A₂ activity but is devoid of any cytotoxic effect on the tested normal or cancerous cell lines. Its primary structure was deduced by N-terminal sequencing and chemical cleavage using Edman degradation and tandem mass spectrometry. It is composed of 121 amino acids with 14 cysteine residues and catalytically active His48 -Asp49 pair. The secondary structure of daboxin P constitutes 42.73% of α-helix and 12.36% of β-sheet. It is found to be stable at acidic (pH 3.0) and neutral pH (pH 7.0) and has a Tm value of 71.59 ± 0.46°C. Daboxin P exhibits anticoagulant effect under in-vitro and in-vivo conditions. It does not inhibit the catalytic activity of the serine proteases but inhibits the activation of factor X to factor Xa by the tenase complexes both in the presence and absence of phospholipids. It also inhibits the tenase complexes when active site residue (His48) was alkylated suggesting its non-enzymatic mode of anticoagulant activity. Moreover, it also inhibits prothrombinase complex when pre-incubated with factor Xa prior to factor Va addition. Fluorescence emission spectroscopy and affinity chromatography suggest the probable interaction of daboxin P with factor X and factor Xa. Molecular docking analysis reveals the interaction of the Ca⁺² binding loop; helix C; anticoagulant region and C-terminal region of daboxin P with the heavy chain of factor Xa. This is the first report of a phospholipase A₂ enzyme from Indian viper venom which targets both factor X and factor Xa for its anticoagulant activity.