Large-scale identification of rodenticide resistance in Rattus norvegicus and Mus musculus in the Netherlands based on Vkorc1 codon 139 mutations

BACKGROUND

Resistance to rodenticides has been reported globally and poses a considerable problem for efficacy in pest control. The most-documented resistance to rodenticides in commensal rodents is associated with mutations in the Vkorc1 gene, in particular in codon 139. Resistance to anticoagulant rodenticides has been reported in the Netherlands since 1989. A study from 2013 showed that 25% of 169 Norway rats (Rattus norvegicus) had a mutation at codon 139 of the Vkorc1 gene. To gain insight in the current status of rodenticide resistance amongst R. norvegicus and house mice Mus musculus in the Netherlands, we tested these rodents for mutations in codon 139 of the Vkorc1 gene. In addition, we collected data from pest controllers on their use of rodenticides and experience with rodenticide resistance.

RESULTS

A total of 1801 rodent samples were collected throughout the country consisting of 1404 R. norvegicus and 397 M. musculus. In total, 15% of R. norvegicus [95% confidence interval (CI): 13–17%] and 38% of M. musculus (95% CI: 33–43%) carried a genetic mutation at codon 139 of the Vkorc1 gene.

CONCLUSION

This study demonstrates genetic mutations at codon 139 of the Vkorc1 gene in M. musculus in the Netherlands. Resistance to anticoagulant rodenticides is present in R. norvegicus and M. musculus in multiple regions in the Netherlands. The results of this comprehensive study provide a baseline and facilitate trend analyses of Vkorc1 codon 139 mutations and evaluation of integrated pest management (IPM) strategies as these are enrolled in the Netherlands. © 2022 The Dutch Pest and Wildlife. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Metabolism of radioactively labeled quinic acid and shikimic acid in healthy and Fusarium-infected tomato plants

Radioactivity from quinic acid-U-¹⁴C was readily incorporated into chlorogenic acid and shikimic acid in healthy andFusarium-infected tomato plants of two varieties, Bonner Beste (susceptible) and Moneymaker (resistant); radioactively labeled shikimic acid, on the other hand, was converted neither to quinic acid nor to chlorogenic acid.Infection led to increased incorporation of¹⁴C inton-butanol extractives, and alcohol-soluble and insoluble esters, except in the resistant variety after feeding of shikimic acid-U-¹⁴C. After infection incorporation into the non-hydrolyzable fraction—which a.o. contains lignin—decreased in the susceptible variety, but it increased in the resistant variety, particularly after administration of shikimic acid-U-¹⁴C.Samenvatting Radioactief kinazuur werd in gezonde en metFusarium geïnfecteerde tomateplanten behorende tot twee variëteiten, Bonner Beste (vatbaar) en Moneymaker (resistent), in chlorogeenzuur en shikimizuur omgezet; laatstgenoemde verbinding werd echter noch in kinazuur, noch in chlorogeenzuur omgezet.Infectie leidde tot een toegenomen incorporatie van¹⁴C in metn-butanol extraheerbare verbindingen, en in alcohol-oplosbare en onoplosbare esters, behalve na toediening van radioactief shikimizuur in de resistente variëteit. Incorporatie in de zg. niethydrolyseerbare fractie, die o.a. lignine bevat, bleek in de vatbare variëteit na infectie geringer te zijn, maar in de resistente variëteit na infectie toe te nemen, vooral na toediening van shikimizuur.     

Structure assignment to biologically produced malathion monocarboxylic acid isomers with 13C-nuclear magnetic resonance

Chemical synthesis of malathion α- and β-monocarboxylic acid yields a mixture of the two structural isomers. These two isomers were separated by preparative anion-exchange chromatography on QAE-Sephadex. ¹³C-Nuclear magnetic resonance of the pure components shows that the main product is the β-isomer, with the α-isomer being present in much smaller quantities. This result was used for identification of hydrolytic malathion metabolites produced by rat tissues. On incubation of malathion with rat liver fractions in vitro it was found that α- and β-monoacid are formed in a ratio of 3:2, whereas this ratio is 9:2 for the metabolites excreted into the urine after intraperitoneal injection of malathion in rats.     

Analysis of polar metabolites of organophosphorus insecticides on an anion-exchange chromatographic column

A simple and rapid procedure is described for the qualitative and quantitative analysis of metabolites of malathion and other insecticides. The omission of an extraction at low pH, and mild conditions of anion-exchange chromatography on QAE-Sephadex prevent the degradation of a malathion metabolite, S-(1-carboxy-2-ethoxycarbonyl)-ethyl O,O-dimethyl phosphorothioate (malaoxon α-carboxylic acid), which takes place under strongly acid conditions. Disadvantages of the commonly used fractionation of malathion and malaoxon metabolites based on partitioning are discussed.     

Assessment of the Exposure and Loads of Acidifying and Eutrophying Pollutants and Ozone,as well as their Harmful Influence on the Vitality of the Trees and the Speulder Forest Ecosystem as a Whole

Within the framework of the Dutch Priority Program on Acidification, 10 yr of research was conducted in a Douglas fir stand at Speulder forest. Research was conducted to establish the loads and levels of acidifying and eutrophying pollutants and ozone, to determine forest vitality characteristics and follow growth parameters and nutrient status in time and to determine the effects of reduction of loads and levels by manipulation experiments. Results indicate that during the last 20 yr critical levels for air pollutants have hardly been exceeded except for ozone, which slightly affected assimilation. Elevated nitrogen deposition has caused several adverse effects including (i) inhibited mycorrhizal development, leading to a decreased base cation and phosphorus uptake; (ii) elevated foliage/root (fine and coarse) ratios, making the forest more sensitive to drought and windthrow; (iii) elevated nitrogen and arginine concentrations in the foliage, associated with relative base cation and phosphorus deficiency, and (iv) elevated nitrate leaching polluting the groundwater. High inputs of acidity have caused elevated ratios of Al to base cations, affecting fine root (uptake) and depletion of the readily available Al pool, thus affecting the long-term sustainability. Despite these effects, forest vitality, in terms of defoliation/discoloration, is reasonable and forest growth even increased in response to nitrogen. The exceedances of critical loads for nitrogen and acidity, however, implies a (large) risk for the long-term sustainability of the Speulder forest.     

Breeding research on rose pigments. 1. The occurrence of flavonoids and carotenoids in rose petals

Summary As a preamble to a breeding programme for colour in roses, the relative quantities of carotenoids, cyanidin, pelargonidin, quercetin and kaempferol were determined in about 200 varieties and some species. Cyanidin was about normally distributed among red varieties, as were carotenoids and flavonols among white and yellow varieties. A positive relationship between pelargonidin and kaempferol was established, and a negative one between pelargonidin and quercetin. No other relations were found between the pigments.     

Characterization and identification of Lactuca sativa cultivars and wild relatives with SDS-electrophoresis (Lactuca sect. Lactuca, Compositae)

Summary Patterns of achene proteins of L. sativa cultivars are mutually compared and compared with L. saligna, L. serriola and L. virosa. L. virosa and L. saligna are easy to identify and are characterized by typical banding patterns. L. sativa and L. serriola share the same banding pattern. They differ clearly from L. saligna and L. virosa. L. sativa and L. serriola are closely related (in terms of similarity), they form a common genepool and L. serriola is involved in the domestication process of L. sativa. Cultivar identification was not possible with the SDS-PAGE method.     

High pressure liquid chromatographic determination of carbohydrates in food products: evaluation of method

A high pressure liquid chromatographic (HPLC) method for determining 5 common carbohydrates in food products was evaluated. Reproducibility data were generated showing a relative standard deviation of 2.8%. Recovery studies on a variety of foods gave an average recovery of 98.8%. The HPLC data for 3 varieties of ready-to-eat cereals were compared with data from 4 independent laboratories using current AOAC chemical methods. The HPLC mean values differed from the chemical mean values by 3.2%.