Applications and mechanisms of wax-based semiochemical dispenser technology for disruption of grape root borer mating.

Grape root borer, Vitacea polistiformis (Harris) (Lepidoptera: Sesiidae), is an important pest of cultivated grapes (Vitis spp.) in the eastern United States from Michigan to Florida. There are few registered insecticides for control of this pest, and their efficacy is limited. Pheromone-based mating disruption is a potential alternative to insecticides for management of V. polistiformis. Wax-based Specialized Pheromone & Lure Application Technology (SPLAT) was tested as a mating disruption method. Deployment densities of 150 dispensers per ha dosed with 5 mg of V. polistiformis pheromone were sufficient to achieve 95% mating disruption during a 7-wk trapping period. The disruption mechanism was determined to be competitive attraction. The release rate of pheromone from these dispensers was quantified to be approximately linear, 77.4 microg/g SPLAT/d. At this release rate, a minimum initial load of 5.4 mg of pheromone per dispenser would be needed to maintain disruption over a 9-10-wk V. polistiformis flight season, approximately 19 August to 21 October in central Florida. It should be noted, however, that the main pheromone component alone, (E,Z)-2,13-octadecadienyl acetate (ODDA), was effective (presumably by a noncompetitive mechanism) at higher loads per area of crop. Due to the cost of synthesis of highly pure isomers of the V. polistiformis pheromone components, mating disruption of V. polistiformis may be more practical with higher doses of commercially produced Zeuzera pyrina L. blend [95% (E,Z)-2,13-ODDA:5% (E,Z)-3,13-octadecadien-1-ol] or with (E,Z)-2,13-ODDA alone than with the V. polistiformis blend at lower rates.

Association and attraction of blueberry maggot fly Curran (Diptera: Tephritidae) to Pantoea (Enterobacter) agglomerans.

The attraction of washed, medium-free cells of Pantoea (Enterobacter) agglomerans to wild, adult Rhagoletis mendax Curran, the blueberry maggot fly, was evaluated in managed blueberry fields in Maine. Attraction was evaluated using Pherocon AM and Ladd traps, each tested with or without washed bacterial cells. Field studies showed significant increases in fly captures on the Pherocon AM traps. Apple volatiles odors on Ladd traps seemed to cancel the effects of bacterial odors. Aerobic heterotrophic bacteria were isolated and identified from alimentary organs within wild R. mendax. Isolates indentified included P. agglomerans. Blueberries collected in the field were surveyed for the presence of P. agglomerans and blueberries containing blueberry maggot larvae and noninfested blueberries were analyzed for amino acid content. Maggot-infested blueberry contained twice the amino acid nitrogen than that of noninfested blueberry. P. agglomerans, like with other pest tephritids, seems to be a cosmopolite with blueberry maggot.

Recognition of foreign oviposition-marking pheromone in a multi-trophic context.

Both phytophagous and parasitic insects deposit oviposition-marking pheromones (OMPs) following oviposition that function to inform conspecifics of a previously utilized host of reduced suitability. The blueberry maggot fly, Rhagoletis mendax Curran (Diptera: Tephritidae), deposits eggs individually into blueberries and then marks the fruit surface with an OMP which reduces acceptance of fruit for oviposition by conspecifics. Diachasma alloeum (Muesebeck) (Hymenoptera: Braconidae) is a parasitic wasp attacking larval R. mendax which also deposits an OMP, signaling conspecifics of a wasp-occupied host. Behavioral studies were conducted testing the hypothesis that the OMP of the parasitic wasp modifies the oviposition behavior of its host fly. In this study, we show that the OMP of D. alloeum is recognized by R. mendax, and female flies will reject wasp-marked fruit for oviposition. Thus, we present a rare demonstration of pheromonal recognition between animals occupying different taxonomic orders and trophic levels. This chemical eavesdropping may enhance the ability of the fly to avoid fruit unsuitable for larval development.

Skeletal muscle and cardiovascular adaptations to exercise conditioning in older coronary patients.

BACKGROUND: Older coronary patients suffer from a low functional capacity and high rates of disability. Supervised exercise programs improve aerobic capacity in middle-aged coronary patients by improving both cardiac output and peripheral extraction of oxygen. Physiological adaptations to aerobic conditioning, however, have not been well studied in older coronary patients. METHODS AND RESULTS: The effect of a 3-month and a 1-year program of intense aerobic exercise was studied in 60 older coronary patients (mean age, 68 +/- 5 years) beginning 8 +/- 5 weeks after myocardial infarction or coronary bypass surgery. Outcome measures included peak aerobic capacity, cardiac output, arterio-venous oxygen difference, hyperemic calf blood flow, and skeletal muscle fiber morphometry, oxidative enzyme activity, and capillarity. Training results were compared with a sedentary, age- and diagnosis-matched control group (n = 10). Peak aerobic capacity increased in the intervention group at 3 months and at 1 year by 16% and 20%, respectively (both P < .01). Peak exercise cardiac output, hyperemic calf blood flow, and vascular conductance were unaffected by the conditioning protocol. At 3 and 12 months, arteriovenous oxygen difference at peak exercise was increased in the exercise group but not in control subjects. Histochemical analysis of skeletal muscle documented a 34% increase in capillary density and a 23% increase in succinate dehydrogenase activity after 3 months of conditioning (both P < .02). At 12 months, individual fiber area increased by 29% compared with baseline (P < .01). CONCLUSIONS: Older coronary patients successfully improve peak aerobic capacity after 3 and 12 months of supervised aerobic conditioning compared with control subjects. The mechanism of the increase in peak aerobic capacity is associated almost exclusively with peripheral skeletal muscle adaptations, with no discernible improvements in cardiac output or calf blood flow.

Cardiac and skeletal muscle adaptations to training in systemic hypertension and effect of beta blockade (metoprolol or propranolol).

Cardiovascular and peripheral adaptations to an aerobic conditioning program were studied in 30 hypertensive adults taking either placebo, beta 1-selective beta-adrenergic blocker (metoprolol) or beta 1-nonselective beta-adrenergic blocker (propranolol). The placebo group increased aerobic capacity (VO2max) 24% (p less than 0.002), largely explained by an increased peripheral arteriovenous (AV) oxygen difference with minimal changes in cardiac size and function. Resting blood pressure and total systemic resistance also decreased. The group taking a beta 1-selective beta blocker increased VO2max 8% (p less than 0.05), reduced resting blood pressure but had no significant change of AV oxygen difference or cardiac size or function. The group taking the beta 1-nonselective beta blocker propranolol had no increase in VO2max, no decrease in resting blood pressure and no cardiovascular or peripheral adaptations to the exercise program. Thus, beta 1-selective and beta 1-nonselective beta blockers attenuate conditioning in hypertensive patients to differing degrees, in each case by blocking peripheral mechanisms of conditioning.

Ribonuclease activity and isoenzymes in raw and processed cows' milk and infant formulas.

Because of evidence of an immunologic role for ribonuclease II (E.C. 3.1.27.5) in mammals, its presence in milk was further characterized to provide a basis for study of possible contributions of its activity to the health of infants. Isoenzymes of ribonuclease II were quantitatively resolved from milk samples as small as 1 ml or less by chromatography on phosphocellulose. Three isoenzymes detected in bovine milk were the previously reported ribonucleases A and B and a form termed ribonuclease II-1. These isoenzymes were in the ratio of 70:30:1. Form II-1 was unique in its inability to hydrolyze polycytidylate. Bovine colostrum contained 10 to 15 times more ribonuclease II-1 than does milk and three times more total ribonuclease II per unit volume. Human milk contains about 1% the concentration of ribonuclease II found in cows' milk. Ribonuclease II activity in milk was quite stable in the acidic conditions of whey production and during low heat treatments. However, most of its enzymatic activity was lost with high heat treatments. No commercially manufactured milk-based or soybean-based infant formula assayed contained nearly as much ribonuclease activity as either human or bovine milk.

Multiple forms of ribonuclease II in mouse liver: relative sizes, subcellular distributions, and pH-activity profiles.

Multiple forms of ribonuclease II (EC 3.1.27.5) have been resolved from extracts of crude fractions of mouse liver by ion-exchange chromatography on phosphocellulose and gel permeation chromatography. The forms are designated 6S, 6L, 5S, 5L, 4S, 4L, 3S, 3L, 2, and 1 in increasing order of apparent cationic character. The forms fall into two series of apparent molecular weight. The small series increases from molecular weight equal to 9000 for form 1 to 14,000 for form 6S. The large series increases from molecular weight equal to 22,000 for form 2 to 44,000 for form 6L. All forms have pH-activity profiles with maxima near pH 7. Activity falls to no less than 30% of this maximum at pHs 5 and 8.5. Relative to the other forms, form 1 has a higher ratio of activity in the alkaline compared with acid pH range. Form 1 is found in the cytosolic, "light" particle, and "heavy" particle fractions. The other forms are largely restricted to the heavy particle fraction. In this fraction the proportion of total activity attributable to each form generally decreases in order from form 1 down to form 6. The results are accommodated by models in which one or more gene products give rise to multiple forms of ribonuclease II by processes involving dimerization and glycosylation.

Multicompartmental distribution of ribonuclease II in mouse liver.

Thirty percent of RNase II (EC 3.1.27.5) is present in the cytosol of mouse liver where it exists in an inactive complex with a protein inhibitor. The remaining 70% of RNase II is active, soluble enzyme unassociated with inhibitor and is distributed in a ratio of 1.3 to 1 between the lumen of reticular elements and the interior of heavy particles. Although heavy particle RNase II resembles acid hydrolases in centrifugal behavior, in other tests including density shift experiments the resemblance is incomplete. In experiments employing lysis induced by L-amino acid methyl esters, RNase II activity is much more latent than the activity of the lysosomal marker, acid RNase. It is postulated that the heavy particle component of RNase II is contained in a secretory vesicle rather than in classic lysosomes.

Purification and characterization of carboxypeptidase A from rat skeletal muscle.

Carboxypeptidase A (EC 3.4.17.1) has been purified 44 000-fold in 33% yield from rat skeletal muscle by a four-step procedure. Purification in the presence of dichlorovinyl dimethyl phosphate conveniently inactivates an accompanying chymotrypsin-like enzyme and other serine protease(s) to ensure isolation of pure carboxypeptidase A free of polypeptide contaminants. The enzyme preparation consists of two components with molecular weights of approximately 39 300 and 37 800. The rat muscle carboxypeptidase is very similar to bovine pancreatic carboxypeptidase A in terms of (1) substrate specificity, (2) kinetics and molecular activity, (3) influence of metal ions on catalysis, (4) interaction with inhibitors, (5) effects of ionic strength on activity, and (6) stability and activity as functions of pH. Both muscle and pancreatic carboxypeptidases exhibit enhanced esterolytic activity when assayed in the presence of a variety of indoles and imidazoles or after incubation at relatively high concentrations of MnSO4. The muscle enzyme is substantially less stable than its pancreatic homologue, and in impure preparations is very much less soluble. The latter property is attributable to a binding substance present in such preparations which renders muscle but not pancreatic carboxypeptidase A insoluble until ionic strength is increased to values near 2 M.

Partial purification and characterization of the components of the neutral ribonuclease II-inhibitor system of normal and distrophic mouse skeletal muscle.

The complexes between a proteinaceous inhibitor and neutral ribonuclease II (EC 3.127.5) purified from low ionic strength extracts of normal and dystrophic mouse muscle are essentially indistinguishable in (a) purification behavior, (b) apparent molecular weights of approximately 50 000, (c) thermal denaturation (50% loss of activity in 5 min at 73.5 degrees C), (d) isoelectric points (pH 4.8), and (e) procedures for reversible resolution into free inhibitor and free RNase II. The free RNase II species are also similar whether obtained by resolution of the purified complexes or by direct isolation of free enzyme from dystrophic muscle. All have apparent molecular weights of 11 500 compared with 13 700 for bovine pancreatic RNase A; all retain 80% of activity after 5 min at 95 degrees C. The active RNase II prepared directly from muscle, by resolution of inhibitor complexes or by organic mercurial treatment of the inhibitor complexes, all have identical pH-activity profiles in 200 mM KC1 with an optimum near pH 7.0. In comparison RNase A has an optimum pH near 7.5 and its activity decreases more rapidly as KC1 concentration is increased above 50 mM KC1. RNase II inhibitor obtained by resolution of the purified complexes or by direct isolation in the free form from normal muscle extracts has an apparent molecular weight of 42 000 and is very sensitive to heat; it loses all activity at 40 degrees C in 5 min. These studies (a) provide methods for obtaining useful amounts of the components of the neutral RNase II - inhibitor system from muscle, (b) provide the first method reported for the reversible resolution of RNase II - inhibitor complexes, (c) fail to show any distinct difference between corresponding components of the system from normal and dystrophic mice, (d) establish interesting differences between the apparently homologous enzymes, murine muscle neutral RNase II, and bovine pancreatic RNase A, and (e) provide a substantially lower molecular weight estimate for RNase II inhibitor from muscle than has been reported for the inhibitor from liver, kidney, and placenta.

Studies of 1-deoxy-D-fructose, 1-deoxy-D-glucitol, and 1-deoxy-D-minnitol as antimetabolites.

1-Deoxy-D-fructose was synthesized in 27% yield from D-glucosamine in a three-step procedure involving Raney nickel desulfurization and oxidative deamination with 3,5-di-tert-butyl- 1,2-benzoquinone applied to appropriate intermediates. 1-Deoxyfructose and its reduction products, 1-deoxyglucitol and 1-deoxymannitol, were tested as substrates and antimetabolites. For sheep liver glucitol dehydrogenase, the Km is 53 mM for 1-deoxymannitol, were tested as substrates and antimetabolites. For sheep liver glucitol dehydrogenase, the Km is 53 mM for 1-deoxyglucitol and 89 mM for 1-deoxymannitol with maximal velocities 33 and 18%, respectively, of that with glucitol as substrate. These results require substantial revision of the long-accepted polyol substrate structural requirements for this enzyme which have been reported to include a 1-hydroxy group and a cis-2,4-dihydroxy configuration. Km is 614 and 280 mM for yeast and muscle hexokinases, respectively, acting on 1-deoxyfructose; maximal velocities are 2 and 5% of those obtained with fructose. 1-Deoxyfructose 6-phosphate is a competitive inhibitor of phosphoglucose isomerase with a Ki of 1.1 mM; this is about the same as Km for the natural substrates. It is also an effective inhibitor of phosphofructokinase but does not alter the cooperativity of the enzyme interaction with fructose 6-phosphate nor exhibit cooperativity in its own interaction therewith. These results suggest that the 1-hydroxy group is not crucial for binding but does play a role in the cooperative interactions of this allosteric protein. At equivalent concentrations, 1-deoxyfructose is somewhat better than 2-deoxyglucose as an inhibitor of erythrocyte glycolysis; the 1-deoxypolyols are ineffective. All three 1-deoxy compounds are readily, though incompletely, absorbed from the intestine of mice; most of the absorbed dose appears in the urine unchanged within 24 h. Whether given by oral or intraperitoneal routes, 2 to 6% of administered deoxypolyol or deoxyketose appears in the urine as ketose or polyol, respectively. No acute toxic effects or growth retardation are noted for any of the 1-deoxy analogues when given to mice at levels where 2-deoxyglucose has such effects. The properties of these 1-deoxy sugar analogues recommend them for further studies of enzyme mechanisms, for metabolic studies, and for testing as therapeutic agents against such organisms as certain mammalian parasites with heavy reliance on glycolysis.