Embryoless Wheat Grain: A Natural System for the Study of Gibberellin-induced Enzyme Formation

Yorkstar wheat, grown in New York State, has a high percentage (10-11) of grains without embryos. The embryoless grains have viable aleurone layers and show no sign of injury. These grains are able to support alpha-amylase synthesis only in the presence of gibberellin A(3) (GA(3)). In the absence of GA(3) some protein synthesis occurs in embryoless grains during the early hours of soaking, indicating that such activity occurs prior to and independent of GA(3) induction of alpha-amylase. The level of beta-amylase on a dry weight basis is the same in embryoless and normal grains and decreases with time of soaking. In the presence of GA(3), beta-amylase decreases at a slower rate. Isoenzymes of alpha-amylase from GA(3)-treated embryoless and normal grains show quantitative as well as qualitative differences. Cycloheximide (60 mug/ml) completely inhibits the synthesis of alpha-amylase by embryoless grains. Of the RNA synthesis inhibitors, actinomycin D (60 mug/ml) was ineffective while 6-methylpurine (60 mug/ml) gave 65% inhibition without decreasing the number of isoenzymes.

Hormonal control of isoperoxidases in lentil embryonic axis

Detachment of the cotyledons from the lentil (Lens culinaris Med.) embryonic axis causes in the latter an increase in total peroxidase activity which is shown to be due to enhancement of specific cathodic isoperoxidases. Kinetin treatment of attached or detached axes promotes activity of essentially the same cathodic isoperoxidases. In addition kinetin enhances the activity of two anodic peroxidases and represses specifically that of a cathodic one. Abscisic acid inhibits the production of all isoenzymes in the presence or absence of kinetin. Cytokinin and abscisic acid actions are discussed in relation to the nature of a wounding hormone and the role of natural inhibitors in cotyledons during germination. Indoleacetic acid stimulates the activity of certain isoenzymes which are also stimulated by kinetin, whereas in others the effects of the two hormones are different. Specific inverse effects of indoleacetic acid and kinetin are demonstrated on the two most cathodic isoperoxidases. Indoleacetic acid-kinetin interactions on the cathodic isoperoxidases have been found in the literature and are discussed as a possible mechanism for explaining interactions of the two regulators on growth and other physiological processes.

Effects of the abortion law, 1967, on a gynaecological unit

In the United Kingdom the more liberal attitude towards abortions engendered by the 1967 Act has increased the work of a gynaecological unit at Salford, Lancashire, by about 10%. In 1964-65 there were 15 therapeutic abortions, and in 1969-70 the number had increased to 447. The increased demand has been catered for by a reduction of stay in gynaecological patients: in fact, the "through-put" has increased and the waiting-list diminished. The increased work-load on the blood transfusion service has been slight, and on the credit side there has been a reduction in the numbers of septic abortions. The major problem has been in the outpatient department, since these cases are time-consuming and it is difficult to make a fair and impartial decision.

Morphactin influences sexual and asexual reproduction in fungi

It has been reported that fungi are not affected morphologically by morphactins. We found, however, that levels of perithecial formation by Nectria haematococca and pycnidial formation by Ascochyta pisi were strikingly lowered by concentrations of morphactin not inhibiting or only slightly inhibiting vegetative growth. Photo- or geo-tropism of Phycomyces blakesleeanus was not affected, and there was no evidence for interference by morphactin in the light reactions stimulating perithecial production by Nectria haematococca.

Eight-Membered Cyclosilicate Rings in Muirite

The determination of the crystal structure of muirite, Ba(10)(Ca,Mn,Ti)(4)Si(8)O(24)(Cl,OH,O)(12) . 4H(2)O, revealed the presence of discrete cyclic silicate anions, (Si(8)O(24))(16-), formed by the condensation of eight silicate tetrahedra. This first reported occurrence of eight-membered rings is of particular interest, because rings with eight tetrahedra are reported to be energetically less stable than rings with six tetrahedra, which have been found in many minerals.

Vulcanizate Properties from a New Perfluoroelastomer

Vulcanizate properties of a new high performance elastomer, a terpolymer of tetrafluoroethylene, perfluoro (methyl vinyl ether) and a small amount of a third perfluoromonomer containing an active cure site, are described. The material may be compounded with various reinforcing agents (black exhibits the greatest reinforcing power) or as a gum stock. Perfluorinated oils such as Krytox § may be added as plasticizers. The vulcanizates show outstanding chemical resistance to many alkalies, acids, oxidizing agents and reducing agents; outstanding resistance to air oxidation at temperatures in the 400 ° – 550 ° F range; low volume swell in many organic fluids such as ketones, esters, nitriles, hydrocarbons and halogenated solvents, including the proprietary hydraulic fluids and jet fuels; and good high temperature (to 550 ° F) compression set.