Glutathione transferase activities toward herbicides used selectively in soybean

Using extracts from suspension-cultured cells of soybean (Glycine max cv. Mandarin) as a source of active enzymes, the activities of glutathione transferases (GSTs) catalysing the conjugation of 1-chloro-2,4-dinitrobenzene (CDNB) and selective herbicides were determined to be in the order CDNB≫ fomesafen>metolachlor=acifluorfen>chlorimuron-ethyl. GST activities showed a thiol dependence in a substrate-specific manner. Thus, GST activities toward acifluorfen and fomesafen were greater when homoglutathione (hGSH), the endogenously occurring thiol in soybean, was used as the co-substrate rather than glutathione (GSH). Compared with GSH, hGSH addition either reduced or had no effect on GST activities toward other substrates. In the absence of enzyme, the rates of hGSH conjugation with acifluorfen, chlorimuron-ethyl and fomesafen were negligible, suggesting that rapid hGSH conjugation in soybean must be catalysed by GSTs. GST activities were subsequently determined in 14-day-old plants of soybean and a number of annual grass and broadleaf weeds. GST activities of the plants were then related to observed sensitivities to post-emergence applications of the four herbicides. When enzyme activity was expressed on a mg^-1 protein basis, all grass weeds and Abutilon theophrasticontained considerably higher GST activity toward CDNB than soybean. With fomesafen as the substrate, GST activities were determined to be in the order soybean≫Echinochloa crus-galli>Digitaria sanguinalis>Sorghum halepense=Setaria faberi with none of the broadleaf weeds showing any activity. This order related well to the observed selectivity of fomesafen, with the exception of A. theophrasti, which was partially tolerant to the herbicide. Using metolachlor as the substrate the order of the GST activities was soybean>A. theophrasti≫S. halepense>Amaranthus retroflexus>Ipomoea hederacea, with the remaining species showing no activity. GST activities toward metolachlor correlated well with the selectivity of the herbicide toward the broadleaf weeds but not toward the grass weeds. Acifluorfen and chlorimuron-ethyl were selectively active on these species, but GST activities toward these herbicides could not be detected in crude extracts from whole plants. © 1997 SCI     

Detection of Salmonella in onion and garlic powders: collaborative study.

The relative efficiency of trypticase soy broth with added 0.5% K2SO3 and lactose broth as pre-enrichment media for recovering Salmonella from onion powder and garlic powder was collaboratively studied. For each spice, 13 collaborators each received 5 duplicate samples; 4 of the 5 replicate samples were inoculated with 1 of 4 levels of S. thompson ranging, at initiation of analysis, from greater than 3 to 93 organisms/g onion powder and greater than 3 to 43 organisms/g garlic powder. Salmonella growth was inhibited in each of these spices as evidenced by a rapid decline of most probable number values in samples determined immediately after and 7 days following inoculation. Collaborative results of cultural analyses demonstrated superiority of the modified tripticase soy broth for recovering Salmonella in each of the 2 spices. The improved method of detecting Salmonella in onion and garlic powders has been adopted as official first action.     

Comparative accuracy of five biochemical systems for identifying Salmonella and related foodborne bacteria: collaborative study.

The comparative accuracy of 4 biochemical diagnostic kits (API, Enterotube, Minitek, and Pathotec) and the conventional (AOAC) tube system for identifying primarily Salmonella and other enteric isolates was collaboratively studied. Each of 11 participating analysts received 40 foodborne isolates (25 Salmonella and 15 non-Salmonella cultures), representing a total of 440 cultures examined by each identification system. In decreasing order of accuracy, the overall number of correctly identified cultures with each of the systems was as follows: AOAC, 423 (96.1%), Minitek, 403 (91.6%), Enterotube, 395 (89.8%), API, 394 (89.5%), and Pathotec, 373 (84.8%). A cost analysis showed that all 4 diagnostic kit systems were less expensive than the conventional AOAC tube system for a single culture identification. Three of the diagnostic kits have been adopted as official first action as alternatives to the AOAC biochemical tube system for presumptive generic identification of foodborne Salmonella and for screening and eliminating non-Salmonella isolates. Routine incorporation of any one of the 3 diagnostic kits, however, should be preceded by the demonstration in the analyst's own laboratory of adequate correlation between the kit and the AOAC system.     

Frequent Exposure of Mice to Crude Brucella abortus Proteins Down‐regulates Immune Response

Mice repeatedly immunized via the intraperitoneal route with a Brucella abortus antigen lost their ability to develop a strong in vitro lymphoproliferative response. This result correlates with a decreased tendency of the lymphoid population to produce interferon‐γ when stimulated in culture with the immunizing antigen. With respect to the humoral response, as the number of immunizations increased, the animals produced more specific immunoglobulin M and immunoglobulin G1 antibodies. It is postulated that the long‐term exposure of an animal to Brucella antigen changes the nature of the immune response from a T‐cell‐mediated response to a humoral response favouring the establishment of the disease.     

Indication and use of electrodiagnostic aids in neurologic disease

Electrodiagnostic aids, electromyography, auditory brainstem response testing, and electroencephalography are extensions of the neurologic examination and provide valuable information about the nervous system. This article discusses the use and interpretation of electrodiagnostic aids in equine neurology as well as the equipment that is employed. It is hoped that with a better understanding of the available electrodiagnostic aids, they will come into greater use.     

Age detection by radiography in Hereford cross Friesian steers.

The mandibles of 78 Hereford cross Friesian steers all showing a full complement of temporary teeth were examined both visually and by radiography to determine whether it was possible to differentiate their various ages. All but one animal were slaughtered at the same weight (1020 lb-464 kg) and their ages at slaughter ranged from 1 year 3 months to 1 year 9 months. Differences were found between the mean ages for stages of resorption of the first temporary incisor roots, stages of first permanent incisor root formation and stages of second incisor crown formation, as determined by radiographic inspection. The results indicated that the age of a group of animals could be defined, but the age range within each development stage meant that it was not possible to define the age of individual cattle.     

Hepatotoxicity of stanozolol in cats

OBJECTIVE: To determine hepatotoxicity of stanozolol in cats and to identify clinicopathologic and histopathologic abnormalities in cats with stanozolol-induced hepatotoxicosis. DESIGN: Clinical trial and case series. ANIMALS: 12 healthy cats, 6 cats with chronic renal failure, and 3 cats with gingivitis and stomatitis. PROCEDURES: Healthy cats and cats with renal failure were treated with stanozolol (25 mg, i.m., on the first day, then 2 mg, p.o., q 12 h) for 4 weeks. Cats with gingivitis were treated with stanozolol at a dosage of 1 mg, p.o., every 24 hours. RESULTS: Most healthy cats and cats with renal failure developed marked inappetence, groomed less, and were less active within 7 to 10 days after initiation of stanozolol administration. Serum alanine transaminase (ALT) activity was significantly increased in 14 of 18 cats after stanozolol administration, but serum alkaline phosphatase activity was mildly increased in only 3. Four cats with serum ALT activity > 1,000 U/L after only 2 weeks of stanozolol administration had coagulopathies; administration of vitamin K resolved the coagulopathy in 3 of the 4 within 48 hours. All 18 cats survived, and hepatic enzyme activities were normal in all cats tested more than 4 weeks after stanozolol administration was discontinued. Two of the 3 cats with gingivitis developed evidence of severe hepatic failure 2 to 3 months after initiation of stanozolol treatment; both cats developed coagulopathies. Histologic evaluation of hepatic biopsy specimens from 5 cats revealed diffuse hepatic lipidosis and cholestasis without evidence of hepatocellular necrosis. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that stanozolol is hepatotoxic in cats.