Comparison of direct electron microscopy and enzyme immunoassay for the detection of rotaviruses in calves, lambs, piglets and foals

Direct electron microscopy (EM) and enzyme-immunoassay (rotazyme) results for the detection of rotaviruses in 346 enteric specimens from calves, lambs, piglets and foals were compared. The rotazyme test was at least 3 times more sensitive than direct EM in diagnosing infection. Rotavirus antigen was demonstrated by rotazyme in 22% of 280 scour samples and in 27% of 66 samples from non-scouring animals. There was an association between diarrhoea and higher amounts of rotavirus antigen. This prevalence of rotaviruses detected in animals with diarrhoea highlights the significant involvement of other pathogens identified in the study including Eimeria, Cryptosporidia, Escherichia coli, Campylobacter, and other viruses.     

Fertility-mycorrhizal-isolate interactions in production of containerized pin oak seedlings

Slow-release fertilizer rates (0, 1.1 and 4.5 kg/m³ of 14 N-6 P-11.6 K Osmocote) and isolates of the ectomycorrhizal fungus Pisolithus tinctorius (Pers.) Coker and Couch affected growth and mycorrhizal development on pin oak (Quercus palustris Meunchh.) seedlings. Mycorrhizae developed on all inoculated seedlings after 8 weeks regardless of fertility regime. Through the first 14 weeks, the best mycorrhizal development occurred on all inoculated seedlings fertilized at the lower fertilizer rate. The higher fertilizer rate delayed mycorrhizal development. However, after 18 weeks there were no significant differences in mycorrhizae on inoculated seedlings receiving fertilizer. Inoculated, non-fertilized seedlings had significantly less mycorrhizae than fertilized seedlings throughout the experiment. Only one isolate increased seedling growth, and only at the higher fertilizer rate. No differences in plant height were found among non-inoculated control and inoculated seedlings at the low fertilizer rate.     

Idiopathic immune complex glomerulonephritis in dogs with multisystem involvement

Renal specimens obtained by biopsy and/or at necropsy from 4 dogs with nephrotic syndrome were studied using light, immunofluorescence, and electron microscopies. The glomerulonephritis observed in these dogs was considered an idiopathic immune complex glomerulonephritis associated with multisystem involvement because causes of glomerulonephritis in these dogs could not be established. Immunoglobulin A was observed in granular deposits in the mesangial and subendothelial regions of the glomeruli. The relationship of the clinical and pathologic features of this disease in dogs to various renal syndromes in human beings are described.     

Insecticidal and fungicidal activity of new synthesized chitosan derivatives

Chitosan, the N-deacetylated derivative of chitin, is a potential biopolysaccharide owing to its specific structure and properties. In this paper, we report on the synthesis of 24 new chitosan derivatives, N-alkyl chitosans (NAC) and N-benzyl chitosans (NBC), that are soluble in dilute aqueous acetic acid. The different derivatives were synthesized by reductive amination and analyzed by 1H NMR spectroscopy. A high degree of substitution (DS) was obtained with N-(butyl)chitosan (DS 0.36) at a 1:1 mole ratio for NAC derivatives and N-(2,4-dichlorobenzyl)chitosan (DS 0.52) for NBC derivatives. Their insecticidal and fungicidal activities were tested against larvae of the cotton leafworm Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae), the grey mould Botrytis cinerea Pers (Leotiales: Sclerotiniaceae) and the rice leaf blast Pyricularia grisea Cavara (Teleomorph: Magnaporthe grisea (Hebert) Barr). The oral feeding bioassay indicated that all the derivatives had significant insecticidal activity at 5 g kg(-1) in artificial diet. The most active was N-(2-chloro-6-fluorobenzyl)chitosan, which caused 100% mortality at 0.625 g kg(-1), with an estimated LC50 of 0.32 g kg(-1). Treated larvae ceased feeding after 2-3 days; the mechanism of action remains unknown. In a radial hyphal growth bioassay with both plant pathogens, all derivatives showed a higher fungicidal action than chitosan. N-Dodecylchitosan, N-(p-isopropylbenzyl)chitosan and N-(2,6-dichlorobenzyl)chitosan were the most active against B cinerea, with EC50 values of 0.57, 0.57 and 0.52 g litre(-1), respectively. Against P grisea, N-(m-nitrobenzyl)chitosan was the most active, with 77% inhibition at 5 g litre(-1). The effect of different substitutions is discussed in relation to insecticidal and fungicidal activity.     

Chemical and organoleptic changes in poultry meat resulting from the growth of psychrophylic spoilage bacteria at 1 degree C. I. Introduction and changes in free amino acids

Changes in pH and in the free amino acid content of chicken breast and leg muscle inoculated with micro‐organisms in pure or mixed culture and stored at 1° C have been measured. Control experiments with aseptically prepared antibiotic‐treated samples separated the effects of autolysis from those attributable to the bacteria. A pigmented strain of Pseudomonas and Pseudomonas putrefaciens at counts up to 10⁸ organisms/g produced smaller effects than autolysis, but somewhat larger changes resulted from the growth to 10⁹/g of the pigmented Pseudomonas and, particularly, of a mixed culture of the two bacteria with three others normally present on chill‐stored chicken. The possible effects of these changes on flavour are discussed.