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Inducible T-strand mobilization from the Ti plasmid of Agrobacterium tumefaciens to the genome of a plant host is mediated by the activation of a cascade of bacterial virulence genes. It is initiated when the bacterium senses the presence of a low molecular weight inducer secreted by the plant. Although many hydroxyphenylpropanoid and phenolic compounds can activate the virulence cascade, the only native inducers that have been identified to date are acetosyringone and hydroxyacetosyringone. A new inducer, the phenylpropanoid glucoside coniferin, has now been isolated from Pseudotsuga menziesii (Douglas-fir). Agrobacterium strains that were more tumorigenic on gymnosperms were more effectively induced by coniferin.

Immunoaffinity techniques using columns of immobilized antibodies raised against zeatin riboside and isopentenyladenosine were found to be effective in isolating cytoklnins from vegetative, female, and male buds of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco). The purified cytokinins were separated by reverse phase high performance liquid chromatography and analyzed by radioimmunoassay. Confirmation of cytokinin identities was by gas chromatography-mass spectrometry. Immediately prior to bud burst, all bud types contained three major cytokinins: isopentenyladenosine, zeatin riboside, and a hexose conjugate of zeatin riboside (not zeatin riboside O-glucoside). Zeatin-type cytokinins were present in relatively high concentration in vegetative and female buds. In male buds, however, relatively high levels of isopentenyladenosine were found together with low levels of zeatin-type cytokinins.

Tritiated N-hydroxysuccinimide acetate was prepared with specific activities up to 5 Ci/mmole and utilized to prepare tritiated triacetyl insulin. Binding of triacetyl insulin to liver plasma membranes was measured by its capacity to displace 125I-monoiodoinsulin. At low concentrations, less than 10 ng/ml triacetyl insulin appears to be as effective as native insulin in reducing the binding of 125I-monoiodoinsulin to plasma membranes. At concentrations of 20 ng/ml and higher, triacetyl insulin is significantly less effective than native insulin in displacing binding of 125I-monoiodoinsulin to plasma membranes. The properties of triacetyl insulin in this system are not ascribable to deacetylation and conversion of the substituted product to native insulin. Biologic activity of triacetylated insulin was studied in two other in vitro systmes. A comparison was made of the capacity of native beef insulin and its triacetyl derivative to stimulate glucose oxidation by epididymal fat pads. At all three concentrations tested (2, 6, and 18 ng/ml), triacetyl insulin exerted considerable activity, although its potency was significantly less than that of native insulin. Similar effects were observed when biologic activity was measured by induction of tyrosine-alpha-ketoglutarate transaminase in a cultured liver cell system where significant activity of triacetyl insulin was found at concentrations of 10(-9)-10(-7) M. In all systems tested, the activity of triacetylated insulin could not be accounted for by deacetylation and conversion to native insulin. In all systems studied, triacetyl insulin was more resistant to degradation than was monoiodoinsulin.

Orally administered ethanol produced dose-related suppression of IRI levels and elevation of IRG levels in fed and fasting rats. Plasma glucose levels were unaffected in the fasting rats, but a moderate hyperglycemic response accompanied the decline in IRI and the rise in IRG observed in the fed rats.

It has been postulated that ethanol-induced changes in carbohydrate hemeostasis are mediated in part by alterations in pancreatic endocrine function. In this study ethanol (40, 120 and 240 mg/dl) produced dose-related suppression of immunoreactive insulin (IRI) release from isolated rat islets perifused with glucose and theophylline. Acetaldehyde inhibited IRI release at a concentration (39 mg/dl) much higher than can be achieved in vivo. A high concentration (29 mg/dl) of acetate did not influence IRI release. These results suggest that the ability of ethanol to inhibit IRI release resides principally in the parent compound and not its metabolites.

In this note a microcomputer-based system for multichannel scaling is described. This system relies on a combination of simple hardware with software support to achieve maximum cost effectiveness.

The gene frequencies of the subtypes of the Gc (group-specific component) protein and PGM1 (phosphoglucomutase) enzyme systems have been determined by means of isoelectric focusing for a California Hispanic population (no. = 404). The Gc subtyping, done by immunofixation on a polyacrylamide gel, gave the following results: 1s = 0.491; 1f = 0.288; 2 = 0.218; variant = 0.0025. The PGM subtyping, done on agarose gel, gave results as follows: 1+ = 0.502; 1- = 0.266; 2+ = 0.128; 2- = 0.104. Because the gene frequencies for Hispanics in both these systems are relatively evenly balanced, the systems are of great value in Hispanic paternity investigations. The average power of exclusion is calculated to be 34.4% (Gc subtyping) and 39.8% (PGM1 subtyping).

Plasma glucose, insulin (IRI) and glucagon (IRG) levels were determined in fasting unanesthetized rabbits following pretreatment of either saline or ethanol (1.5 g/kg p.o.) and i.v. infusion of either saline or arginine (10 mg/kg/min for 30 min). Ethanol lowered plasma glucose and IRI levels but raised IRG levels in rabbits infused with saline. Arginine-induced hyperglycemia and hyperinsulinemia were markedly suppressed by ethanol so that any further increase expected by the infusion of arginine was minimized. Thus, ethanol not only alters basal levels of IRI, IRG and glucose but also suppresses arginine-stimulated levels as well.