The toxicity of dieldrin (HEOD) to domestic fowl

Domestic fowl were fed control diet or diets containing 10 or 20 μg/g HEOD. Eggs and samples of blood were collected at intervals and the concentration of HEOD was determined. The concentrations of HEOD in body tissues were also determined after 7 and 13 months. Some of the birds died, but the health of the remainder appeared to be unaffected. The hens of the 20 parts/million group showed an increased egg production, but chick mortality in this group was higher than in the other two groups. The dynamics of HEOD in domestic fowl were qualitatively similar to that in other vertebrates and was consistent with the mamillary type compartmental model.     

Depot specific endocrine control of fatty acid synthesis in adipose tissues of foetal lambs

Chronic endocrine control of fatty acid synthesis in perirenal and subcutaneous adipose tissues of foetal lambs has been investigated. Maintenance of explants of subcutaneous adipose tissue in culture for 48 hr with insulin and dexamethasone (a glucocorticoid analogue), either singly or in combination showed that the two acted synergistically to increase the rate of fatty acid synthesis. Growth hormone inhibited the ability of insulin plus dexamethasone to increase the rate of fatty acid synthesis in explants of subcutaneous adipose tissue. In contrast neither insulin nor dexamethasone either singly or together increased the rate of fatty acid synthesis in perirenal adipose tissue; growth hormone also had no effect on the rate of fatty acid synthesis in this depot. These studies show that fatty acid synthesis is under distinct endocrine control in subcutaneous and perirenal adipose tissues in foetal lambs.     

Flea (Pulex simulans) infestation in captive giant anteaters (Myrmecophaga tridactyla).

A pair of captive adult giant anteaters (Myrmecophaga tridactyla) presented heavily infested with a flea species (Pulex simulans) commonly found on Virginia opossums (Didelphis virginiana) and raccoons (Procyon lotor) in the central United States. In this case, the flea was demonstrated to have completed its entire life cycle with the anteaters as the host. A single treatment of topical imidacloprid, coupled with removal and replacement of infested bedding, was rapidly effective at controlling the infestation and no adverse effects of the drug were noted. Control of the anteater infestation also removed the flea infestation of aardvarks in the same building.     

Flea blood feeding patterns in cats treated with oral nitenpyram and the topical insecticides imidacloprid, fipronil and selamectin

A series of studies was conducted to determine the effect of systemically and topically active insecticides on blood consumption by fleas (Ctenocephalides felis). Infestations were conducted by placing fleas into plexi-glass chambers attached to the lateral rib cage of domestic short-hair cats. After pre-defined periods, fleas and flea feces were extracted using vacuum aspiration and spectrophotometrically analyzed for hemoglobin using Drabkin's reagent. To determine how rapidly nitenpyram kills actively feeding fleas, a single oral treatment was administered 24h after infestation. To determine the effect of nitenpyram on blood consumption of newly acquired fleas, cats were infested with fleas 1h post-treatment and fleas and flea feces from both studies were extracted at 15, 30, 60, 120, 240 and 480min post-treatment or post-infestation. To compare the effects of topically versus systemically active insecticides, 20 cats each with 2 chambers attached, were randomly allocated among groups and were infested with fleas 1h after each of 4 nitenpyram treatments, or at 7, 14, 21 and 28 days after a single application of commercial spot-on formulations of fipronil, imidacloprid or selamectin. Infestations were also completed for untreated (control) cats. Twenty-four hours after infestation, fleas and flea feces were removed for host blood quantification. If at any time, flea blood consumption in a treated group did not significantly differ from that of fleas infesting controls, that treatment group was withdrawn from the study. Nitenpyram effects on actively feeding fleas were first observed at 60min post-dosing when 38% of fleas were dead or moribund, and at 240min 100% were dead or moribund. Nitenpyram produced a significant reduction in flea blood consumption (p<0.05), which appeared to cease 15min after infestation. For the treatment comparisons, significantly more (p<0.05) blood was consumed by fleas taken from imidacloprid and fipronil-treated cats than from the nitenpyram or selamectin groups. Only on nitenpyram- or selamectin-treated cats were there significant reductions (p<0.05) in flea blood consumption on days 21 and 28, with significant difference (p>0.05) between these two groups on day 28. In this study systemically acting insecticides such as nitenpyram, and the topically applied but systemically active insecticide selamectin, were more effective in interfering with flea blood feeding than were imidacloprid and fipronil.     

Blending of pheromone lures for two exotic European pest elaterid beetles

Two exotic European click beetle species, Agriotes obscurus and Agriotes lineatus, were introduced into the lower Fraser valley of British Columbia over a century ago, and are now predominant pests of a number of arable crops. A semiochemical-based method of monitoring both species has been developed as a part of an integrated pest management plan, and there is interest in mass trapping with pheromones as a management tool. A. obscurus females produce primarily geranyl octanoate (G8) and geranyl hexanoate (G6), while A. lineatus females produce both G8 and geranyl butanoate (G4). The current studies examined the possibility of using a blend of G8, G6, and G4 components in a single lure to trap both species simultaneously. A blended G8, G6 and G4 lure in a 1:1:1 ratio was, on average, 1.42 times more attractive to A. lineatus males than standard A. lineatus pheromone lures, but caught only 0.24 times the number of A. obscurus in standard A. obscurus traps. Blended traps, therefore, are effective for monitoring and mass trapping of A. lineatus, but only for detection of A. obscurus.     

Rubidium-strontium chronology and chemistry of lunar material

Igneous lunar rocks divide into two chemical types, probably representing two rock units. They form separate close groups on the isochron diagram; no total rock age is valid unless the rocks are cogenetic. Mineral isochrons prove that one type has an age of 3.80 +/-0.11 billion years, equal to the line joining total-rock groups, and the initial ratio of strontium-87 to strontium-86 of both types is close to 0.6994. Soil and breccias chemically resemble a mixture of the two igneous types, with a superimposed variation of mineral components, plus a small transferred component rich in nickel, copper, zinc, and possibly stron-tium-87.