Abscission-inducing properties of methyl jasmonate, ABA, and ABA-methyl ester and their interactions with ethephon, AgNO3, and malformin

The biological activities of methyl jasmonate, ABA, methyl abscisate, and malformin were compared in a variety ofVigna radiata abscission tests. Although each compound diminished or completely negated the antiethylene properties of Ag⁺, differences in potency were observed. ABA and ABA-Me stimulated leaf abscission in the dark, potentiated abscission with low concentrations of ethephon, and interacted synergistically with malformin, whereas methyl jasmonate was inactive in each of these tests. Methyl jasmonate was most active in potentiating leaf abscission induced by high ethephon concentrations and stimulated petiole abscission, whether applied proximally or distally, from debladed explants. In two tests, negation of Ag⁺ activity and interaction with malformin, ABA concentrations as low as 0.1 M were biologically active and indicated that ABA can be a highly active abscission-inducing compound. Based on differences in biological activity, it was concluded that the modes of action of methyl jasmonate, ABA, and malformin were different.Journal Paper No. 9811 of the Purdue Agricultural Experiment Station.     

Amino acid sequence homologies between H1 and H5 histones

Ehrlich ascites cell microsomes catalyze the exchange of the acyl group of acyl dihydroxyacetone phosphate with free fatty acids. The reaction does not require ATP and CoA.     

Action of 5-thio-D-glucose in the control of glycogen depolymerization

With muscle glycogen phosphorylase a and b, 5-thio-$\text{D}$-glucose is a non-competitive inhibitor toward phosphate where it has a K_i of 13 mM and 5.1 mM, respectively, and produces a mixed type of inhibition when glycogen is the substrate.5-Thio-$\text{D}$-glucose enhances diaphragm phosphorylase phosphatase activity to the same extent as $\text{D}$-glucose, yet the thioanalog does not affect phosphorylase b kinase. Thus, the action of 5-thio-$\text{D}$-glucose on glycogen degradation proceeds by inhibition of phosphorylase a and b and by inactivation of phosphorylase a through converting it to the b form.     

Pretranslational regulation of alpha 2u-globulin in rat liver by growth hormone

Hypophysectomy is known to cause complete suppression of the hepatic synthesis alpha 2u-globulin. The effect of hypophysectomy on the synthesis of alpha 2u-globulin can be reversed by multiple hormone treatment. The role of pituitary growth hormone in the multihormonal regulation of alpha 2u-globulin in rat liver was examined in the hypophysectomized male rats with and without growth hormone supplementation. Daily treatment of hypophysectomized rats with 5 alpha-dihydrotestosterone, corticosterone, thyroxine, and growth hormone for 8 days caused about 80% recovery in the hepatic content of alpha 2u-globulin and its corresponding mRNA as determined by radioimmunoassay, in vitro translation, and liquid hybridization with a cloned cDNA probe. However, omission of growth hormone from the treatment regimen failed to raise hepatic alpha 2u-globulin and its mRNA to more than 5% of the normal control. The possible effect of growth hormone on the translation of the mRNA for alpha 2u-globulin was examined with cultured hepatocytes derived from growth hormone-deficient rats. Culture of these cells in the presence of growth hormone for 24 h did not turn on the synthesis of alpha 2u-globulin. These results indicate that growth hormone regulates the synthesis of alpha 2u-globulin by acting at a step antecedent to mRNA translation.     

Analysis of picogram quantities of indole-3-acetic acid by high performance liquid chromatography-fluorescence procedures

The use of spectrofluorimeter coupled to a reverse phase high performance liquid chromatography column permits selective detection of indole-3-acetic acid at the low picogram level. The value of the technique is demonstrated by the analysis of endogenous IAA in elongating shoots, xylem sap and callus of Douglas-fir. The data are also used to illustrate a procedure whereby the accuracy of chromatographic analyses can be verified within definable probability limits.Abbreviations GC-MS combined gas chromatography-mass spectrometry - HPLC high performance liquid chromatography - IAA indole-3-acetic acid - SEC steric exclusion chromatography - SICM selected ion current monitoring Technical Paper No. 5379 from the Oregon State University Agricultural Experiment Station     

Rhizogenesis fromNigella sativa protoplasts

Summary Protoplasts were isolated for the first time from cell suspensions ofNigella sativa. These were then cultured in media and observed at regular intervals. Different concentrations of auxin and kinetin were tried with success to obtain root from the callus tissues of the protoplasts.