Determination of extractable and non-extractable radioactivity from prairie soils treated with carboxyl- and ring-labelled [14C]2,4-D

Ring- and carboxyl-labelled [¹⁴C]2,4-D were incubated under laboratory conditions, at the 2 g/g level, in a heavy clay, sandy loam, and clay loam at 85% of field capacity and 20 1C. The soils were extracted at regular intervals for 35 days with aqaeous acidic acetonitrile, and analysed for [¹⁴C]2,4-D and possible radioactive degradation products. Following solvent extraction, a portion of the soil residues were combusted in oxygen to determine unextracted radioactivity as [¹⁴C]carbon dioxide. The remaining soil residues were then treated with aqueous sodium hydroxide, and the radioactivity associated with the fulvic and humic soil components determined. In all soils there was a rapid decrease in the amounts of extractable radioacitivity, with only 5% of that applied being recoverable after 35 days. All recoverable radioactivity was attributable to [¹⁴C]2,4-D, and no [¹⁴C]-containing degradation products were observed. This loss of extractable radioactivity was accompanied by an increase in non-extractable radioactivity. Approximately 15% of the applied radioactivity, derived from carboxyl-labelled [¹⁴C]2,4-D, and 30% from the ring-labelled [¹⁴C]2,4-D was associated with the soil in a non-extractable form, after 35 days of incubation. After 35 days, less than 5% of the radioactivity from the carboxyl-labelled herbicide, and less than 10% of the ringlabelled material, was associated with the fulvic components derived from the three soils. Less than 5% of the applied radioactivities were identifiable with any of the humic acid components. It was considered that during the incubation [¹⁴C]2,4-D did not become bound or conjugated to soil components, and that non-extractable radioactivity associated with the three soil types resulted from incorporation of radioactive degradation products, such as [¹⁴C]carbon dioxide, into soil organic matter.     

Absorption and translocation of 14C fosamine by three woody plant species

Absorption and translocation of ¹⁴C fosamine (ethyl hydrogen (aminocarbonyl) phosphonate) and/or fosamine metabolites were monitored in intermediately susceptible seedling black cherry (Prunus serotina Ehrh.) and resistant seedling rhododendron (Rhododendron sp.) and magnolia (Magnolia sp.). The mid two-thirds of the third leaf below the apical bud of each plant was treated with 0·5 μCi ¹⁴C fosamine (carbonyl carbon labelled). Plants were harvested 3, 7 and 14 days following treatment. In black cherry the majority of ¹⁴C absorption and translocation occurred during the second week following treatment, while magnolia and rhododendron translocated and absorbed most of the ¹⁴C within 3 days after treatment. Retention of ¹⁴C in the treated portion of the treated leaf did not differ between species. However, total translocated ¹⁴C was greatest in black cherry, less in magnolia, und minimal in rhododendron. Magnolia translocated ¹⁴C basipetally, while black cherry translocated acropetally, as well as basipetally. Absorpiion et migration de la fosamine ¹⁴C chez trois espèces de plantes ligneuses L'absorptlon et la migration de La ¹⁴C fosamine ((amino carbonyl) phosphonate d'éthyle hydrogène) et/ou de ses métabolites, ont étéétudiées chez des plantules moyennement sensibles de Prunus serotina (Ehrh.) et chez des plantules résistantes de rhododendron (Rhododendron sp.) et de magnolia (Magnolia sp). Les deux tiers moyens de la troisième feuille en-dessous du bourgeon apical de chaque plant ont été traités avec 0.5 Ci ¹⁴C de fosamine (marquée sur le carbone du carbonyl). Les plantes ont été récoltées 3, 7 et 14 jours après le traitement. Chez P. serotina, la plus grande partie de l'absorption et de la migration du ¹⁴C a eu lieu durant la deuxième semaine après le traitement, alors que chez le magnolia et le rhododendron, le maximum d'adsorption et de migration s'est situé dans les trois jours qui ont suivi le traitement. La rétention du ¹⁴C dans la partie traitée n'a pas variè d'une espèce à l'autre. Toutefois, la quantité totale de ¹⁴C qui a migré a été plus grande chez P. serotina, moindre chez le magnolia et minimaie chez le rhododendron. Chez le magnolia, la migration du ¹⁴C s'opere dans le sens basipète, alors que chez le P. serotina. elle s'effectue aussi bien dans le sens acropète que dans le sens basipète. Aufnahme- und Trunstokaiion von ¹⁴C-Fosaminc bei drei Gehölzpflanzen Es wurde die Aufnahme und die Translokation von ¹⁴C Fosamine (O-Äthyl-aminocarbonylphosphonsäure) und/oder seiner Abbauprodukte bei drei Gehölzarten beobachtet. Verwendet wurden Sämlinge der Traubenkirsche (Prunus serotina Ehrh.), die eine mittlere Empfindlichkeit zeigt und Sämlinge des resistenten Rhododendron (Rhododendron sp.) und der ebenfalls resistenten Magnolie (Magnolia sp.). Die mittleren zwei Drittel des dritten Blattes unterhalb der Endknospe wurden bei jeder Pflanze mit 0.5 μCi ¹⁴C-Fosamine (markiert am Carbonylkohlenstoff) behandelt. Die Pflanzen wurden nach 3, 7 und 14 Tagen nach der Behandlung geerntet. Bei der Traubenkirsche wurde während der zweiten Woche am meisten ¹⁴C aufgenommen und transloziert, während dies bei der Magnolie und dem Rhododendron bereits innerhalb der ersten drei Tage der Fall war. Bezüglich der Retention von ¹⁴C in der behandelten Blattfläche unterschieden sich die drei Arten nicht. In der Traubenkirsche wurde aber am meisten ¹⁴C transloziert, weniger in der Magnolie und am wenigsten im Rhododendron. Die Magnolie translozierte das ¹⁴C basipetal, während die Traubenkirsche akropetal wie basipetal translozierte.     

Studies on bovine demodecosis in northern Nigeria

Summary The study reported in the present paper discusses the clinical and histological picture of bovine demodecosis and the morphology of Demodex mites as seen in four cows suffering from generalized demodecosis. There were no clinical signs of other skin affections. Changes in both the number and the appearance of visible skin lesions were seen and related to the level of nutrition and the exposure to sunshine of the cattle. Histological sections of some skin nodules showed the presence of mite colonies in the hair follicles. Only adults were seen in the sebaceous glands. Microscopical study of the morphology of the mites revealed the presence of two types of demodicids in the skin lesions and three types from epilated eyelashes. Morphological criteria are presented to aid in identification of species and of life stages.     

Egg transmission of egg drop syndrome 1976 virus in fowl

Summary Egg transmission of egg drop syndrome 1976 virus (BC14 virus) in fowl was demonstrated in the second and third week after experimental infection. Eggs of BC14 virus infected hens were incubated weekly after disinfection with formaline gas. After 18 days of incubation, eggs with live embryos were homogenized. This egg material was fed to adult hens, housed in isolators. Seroconversion in these birds demonstrated egg transmission. It is suggested that egg transmission occurs as a result of viremia.     

Pasteurella haemolytica infections in sheep

Summary Pasteurella haemolytica causes two distinct disease syndromes in sheep. P. haemolytica biotype A causes septicaemia in young lambs and pneumonia in all ages of sheep. Biotype T produces an acute systemic disease affecting principally the upper alimentary tract and lungs in young adult sheep. The bacteriology, epidemiology and clinical and necropsy findings of the two diseases are described and the current situation regarding their experimental reproduction and immunology is reviewed.     

Precocene II metabolism: Comparative in vivo studies among several species of insects,and structure elucidation of two major metabolites

Several species of insects, exhibiting varying responsiveness to the juvenile hormone antagonist precocene II (6,7-dimethoxy-2,2-dimethylchromene), were challenged topically with a tritiated preparation of the title compound. Metabolism of [³H]precocene II was subsequently examined by withdrawing hemolymph samples from treated animals at appropriate time intervals and characterizing the extractable radiolabel chromatographically. Quantitative (or qualitative) differences observed between the respective metabolic profiles were found not correlative with specimen sensitivity to precocene. Production of two heretofore unreported metabolites, identified by spectral and chemical means as O-β-glucosides of 6- and 7-monodemethylated precocene II, was demonstrated in both sensitive and insensitive species. No evidence for the presence of a hemolymphborne, biologically effective “activated metabolite” produced in vivo by precocene-susceptible insects could be found. The latter finding may well argue for in situ bioactivation of precocene at the target tissue(s) by these sensitive insects.     

The relationship between the pharmacokinetics of intravenous cismethrin and bioresmethrin and their mammalian toxicity

The distribution and excretion of [¹⁴C]alcohol-labeled cismethrin and bioresmethrin was determined after intravenous administration to rats. Initially the label distribution of both isomers was similar, but differences occurred at later times mainly due to the retention of 5-benzyl-3-furylcarboxylic acid, a metabolite of bioresmethrin, in high concentration in the blood. Retention of this metabolite accounted for the slower excretion of bioresmethrin label compared to cismethrin. After administration of either isomer, parent pyrethroid was rapidly cleared from the blood and liver, and both isomers rapidly entered the central nervous system reaching peak concentrations within 2–5 min. Brain cismethrin concentrations exceeding 3.5 nmol/g were associated only with animals showing tremors. These levels of cismethrin are maintained for up to 30 min but bioresmethrin was depleted more rapidly possibly due to brain metabolism. It is concluded that the low toxicity of bioresmethrin is possibly due to the inability of this isomer to interact with the site of action in the central nervous system and not, as previously suggested, primarily because of more rapid metabolism in the liver.