Azomethines of sec-butylamine for the control of penicillium decay of oranges

Imines, synthesised by the reaction of sec-butylamine (SBA, 2-amino-butane) with pentan-2-one, heptan-2-one, octan-2-one, undecan-2-one, benzaldehyde and 2-furaldehyde, were evaluated as vapour-phase treatments to prevent the infection of oranges by Penicillium digitatum. All the imines provided decay control equivalent to SBA when they were introduced into the fruit container at a rate equivalent to 16.4 mg SBA litre^?1 air volume. The carbonyl compound component of the imines, tested alone at a five-fold higher rate, did not reduce fruit decay. All the imines were stable in the gaseous state in dry air. The imines of pentan-2-one and undecan-2-one were hydrolysed rapidly in a humid environment, indicating that their action against P. digitatum was due to the release of SBA into the atmosphere around the fruit. The instability of the imines of the aliphatic ketones makes them unsuitable as generators of SBA in packages. The imines derived from benzaldehyde and 2-furaldehyde were stable in moist air, but were hydrolysed to a significant degree on moist filter paper, especially at pH < 7. These aromatic imines were absorbed from the atmosphere by the fruit and were hydrolysed rapidly in water, and in a buffer solution that represented the environment in fresh injuries on fruit. Apparently all the imines tested generated SBA in the fruit environment, and this SBA accumulated at potential infection sites, where it prevented the development of decay.     

Protection tests against parasitic diseases

The development of parasite immunology during the last decade has been highly beneficial to our understanding of immune processes against parasites, and recent research has been devoted to the target antigens of effector mechanisms, especially those localized on the surfaces of the pathogens. In this context, define antigenic structures have been identified, which induced significant degree of protection. In malaria, circumsporozoite and merozoite proteins, with large repetitive sequences, have been isolated from various species of Plasmodium and cloned. Monoclonal antibodies produced against these antigens inhibited the invasion of host cells by living parasites. Some results have also been obtained in protective immunity against Leishmania and Toxoplasma. In schistosomiasis, the main characteristic of defence processes is the narrow association between cellular and humoral immunity in antibody-dependent cell-mediated cytotoxic mechanisms. Eosinophils, macrophages, and platelets efficiently killed schistosome larvae when activated by specific antibody of anaphylactic classes, especially IgE. Some of the target antigens have been characterized and cloned. The transfer to normal animals of monoclonal antibodies, and, in one case, of an anti-idiotype antibody, has induced a significant protection against challenge infestations. Optimistic perspectives can therefore be opened concerning an efficacious immunoprophylaxis of an increasing number of parasitic diseases. An adequate conjunction between potentially protective antigens and selective immunomodulators and adjuvants should lead to vaccination. Such an aim nowadays appears as more than a hope.     

Influence of oxygen,carbon dioxide and carbon monoxide levels on decay of head lettuce after harvest

Lettuces, Lactuca sativa L. var. capitata, half of which were inoculated with Botrytis cinerea Pers. ex Fr., were stored for 14 days at 7.5°C in all combinations of the following gases: 5 and 21% O₂, 0 and 3% CO₂, 0 and 1% CO. Decay was inhibited by 5% O₂ and 3% CO₂, and a combination of these was the most effective mixture. CO at 1% had no effect on decay. The results were similar for lettuces from the coastal or desert areas of California, but more decay occurred in the former than in the latter.     

Photodecomposition of piperazine in water by ‘sunlight’ ultraviolet radiation

A solution of piperazine in water was photochemically oxidised by the dissolved oxygen when irradiated with ‘sunlight’ ultraviolet radiation obtained with a Hanau Q-300 lamp, or with RUL-300 nm lamps. Sensitisers (riboflavin, acetone and benzophenone) did not increase the rate of the oxidation induced by the RUL-300 nm lamps; however, they (especially riboflavin) accelerated the oxidation induced by the Hanau Q-300 lamp. A large number of products were observed in the sensitised oxidation but they were not analysed further. The irradiation mixture of the non-sensitised photo-oxidation, when 65% of the initial piperazine had been transformed, contained piperazine (35%), glycine (approximately 25%) and three unidentified compounds in equal amounts (approximately 13% each); the same products were obtained with both irradiation systems. The photo-oxidation of piperazine, a metabolite of the fungicide triforine, 1,4-bis(2,2,2-trichloro-l-formamidoethyl)piperaerazine, could thus be a way for the latter's biodegradation at a surface, or in plant tissues, this biodegradation having already been observed.     

Über den in-vitro-Einfluß der Toxine von enteropathogenen Escherichia Coli auf die Motorik der Darmsegmente

The in vitro effect of toxins of enteropathogenetic Escherichia coli on the motility of gut segments In vitro experiments on the motility of segments of the jejunum and ileum of rabbits and pigs showed that the differentiation of the toxins of enteropathogenic E. coli by this technique was very doubtful. The enteropathogenic strains 0149: K 91 H 10 and 0138: K 81 were compared with the non-pathogenic strain 07 and with acetylcholine.     

The nature of bound residues derived from triforine in barley plants

The shoots of barley plants root-treated with [³H]-triforine fungicide (uniformly labelled in the piperazine ring) were analysed 30 days after treatment. Methanol extraction left a solid plant residue which contained 33% of the total ³H which had been incorporated into the shoots. Methanol acidified with hydrochloric acid extracted a further 18% of the triforine-derived bound residues as N-[2,2,2-trichloro-1-(piperazin-1-yl)ethyl]formamide (8%), and piperazine (10%). In the plants, these compounds had thus been complexed to plant constituents. Hot dimethyl sulphoxide (DMSO) extracted a further 13% of the total ³H, leaving a solid residue (mainly cellulose) which contained 2% of ³H, perhaps incorporated into the cellulose. Evaporation of the solvent from the DMSO extract gave a solid, the radioactivity of which (13%) could not be extracted by methanol. A part (7%) of this radioactivity could be released by successive hydrolysis with amyloglucosidase and β-glucosidase, which generated a complex mixture of polar and water soluble unknown radioactive compounds not including piperazine. These latter compounds would be the products of extensive metabolism of triforine (and its metabolite piperazine) bound to, or incorporated into starch. Most (11%) of the radioactivity of this solid could be released by hydrochloric acid hydrolysis, which also generated a complex mixture of polar and water soluble unknown radioactive compounds not including piperazine; a part (4%) of them could have been associated with lignin in the plant.     

A review of methods for the determination of polychlorodibenzo-p-dioxins and polychlorodibenzofurans in phenoxyalkanoic acid herbicides

A review is presented of the analytical methods for the detection and determination of polychlorodibenzo-p-dioxins and polychlorodibenzofurans in phenoxyalkanoic acid herbicides.     

Pharmacokinetics of xylazine, 2,6-dimethylaniline, and tolazoline in tissues from yearling cattle and milk from mature dairy cows after sedation with xylazine hydrochloride and reversal with tolazoline hydrochloride

Xylazine hydrochloride was administered i.m. at 0.35 mg/kg to 13 steers and 10 lactating dairy cows at Time 0. Ten minutes later, tolazoline hydrochloride was given i.v. at 4 mg/kg. Tissue and milk samples were analyzed using gas chromatography with nitrogen and phosphorous detection to determine concentrations of xylazine, 2,6-dimethylaniline (a toxic metabolite of xylazine), and tolazoline (at various intervals). Concentrations of xylazine and 2,6- dimethylaniline were below the limit of quantitation (10 microg/kg) by 72 hours in tissues and 12 hours in milk. The concentration of tolazoline was below 10 microg/kg by 96 hours in tissues and 48 hours in milk. Based on the results of these residue studies submitted by the sponsoring agency to the Ministry of Agriculture and Forestry in New Zealand, withholding periods for both xylazine hydrochloride and tolazoline hydrochloride injection were established.