First report of Tuta absoluta resistance to diamide insecticides

Journal of Pest Science - The tomato borer Tuta absoluta (Lepidoptera: Gelechiidae) is an invasive pest of tomato crops that is rapidly expanding around the world. It is considered a devastating...     

Determination of 12 type A and B trichothecenes in cereals by liquid chromatography-electrospray ionization tandem mass spectrometry

A new sensitive method for the simultaneous determination of 12 trichothecenes (deoxynivalenol, nivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, fusarenon X, T-2 toxin, HT-2 toxin, neosolaniol, monoacetoxyscirpenol, diacetoxyscirpenol, T-2 triol, and T-2 tetraol) by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) is presented. The development of the method and investigations on the matrix influence on the MS signal are described in particular. The matrix effect was thereby minimized by using an internal standard, a special mobile phase, and specific fragmentation parameters. The sample was extracted with acetonitrile/water (84:16, v/v), and the extract was cleaned up with a MycoSep 227 column. Quantification was based on the internal standard de-epoxy-deoxynivalenol. Calibration curves were linear between 16 and 1600 ng/g, and the limits of detection ranged from 0.18 to 5.0 ng/g. The developed method was applied for the determination of trichothecenes in 120 naturally contaminated wheat and oat samples.     

Development and application of solvent-free extraction for the detection of aflatoxin M1 in dairy products by enzyme immunoassay

The official methods for the quantification of aflatoxin M1 in dairy products (cheese and yogurt) include extraction into dichloromethane or chloroform, evaporation of the solvent, partitioning of the reconstituted residue with hexane, and subsequent analysis. To secure a rapid and inexpensive screen for aflatoxin M1 contamination, a sensitive competitive ELISA, using a rabbit polyclonal antibody, was developed for measuring aflatoxin M1 in milk and used in a comparative study for measuring the extraction efficiency of aflatoxin M1 in aqueous or organic solvent buffers using yogurt samples. An aqueous sodium citrate solution was found to be suitable for extracting aflatoxin M1, thus eliminating the need for organic solvents. The citrate extraction proved to be efficient (recovery ranged from 70 to 124%) in fortified samples of very different kinds of dairy products, including yogurt and six types of cheese. Fourteen yogurt and cheese samples were extracted with citrate solution and analyzed by ELISA. A good correlation was observed (y=0.95x-0.59, r2=0.98) when the data were compared with those obtained through the official method, across a wide range of aflatoxin M1 contaminations (10-200 ng/kg).     

Variation in morphology and seed production of snow clover [<Emphasis Type="Italic">Trifolium pratense</Emphasis> L. subsp. <Emphasis Type="Italic">nivale</Emphasis> (Koch) Arcang.] germplasm from the Rhaetian Alps,Italy

A recent approach to restoration of degraded mountain landscapes (e.g. ski slopes) recommend to sow seed mixtures including ‘site-specific’ species, i.e. native germplasm adapted to the prevailing conditions and ecologically compatible with the area of intervention. To better exploit the potential of these species and enhance their spread in revegetation projects, deeper knowledge is needed, however, on the existing variation in their germplasm, particularly for economically useful traits such as seed yield. Snow clover is one of the recommended ‘site-specific’ legumes. This study evaluated 12 populations of snow clover, collected in three valleys of the Rhaetian Alps, Italy, to assess their variation and highlight any promising material. The evaluation encompassed a mountain and a lowland site, to verify the behaviour of the germplasm also in one environment markedly different from that of origin. Differences among valleys were observed for flower colour, growth habit and type, flowering time and susceptibility to mildew, although the overall pattern of phenotypic diversity was similar among valleys. Some effect of the evaluation site on the expression of morphological and seed production traits, and on the overall diversity, was also evident. Furthermore, the lowland site experienced very high plant mortality towards the end of the first growing season. Individual populations proved a valuable source of variation for seed production. Some populations, in particular, were worth of attention for a possible selection of high-seed-yielding snow clover cultivars. An assessment of the mating system suggested a lack of self-tripping or an almost absolute self-incompatibility in snow clover.     

Monitoring of <Emphasis Type="Italic">Francisella noatunensis</Emphasis> subsp. <Emphasis Type="Italic">orientalis</Emphasis> in farmed Nile tilapia (<Emphasis Type="Italic">Oreochromis niloticus</Emphasis>) in Brazil

Francisella noatunensis orientalis is a bacterium that causes emerging bacteriosis in Nile tilapia (Oreochromis niloticus) in many parts of the world, including Brazil. It is a non-motile, Gram-negative, strictly aerobic, facultative intracellular coccobacillus. This species of bacteria is responsible for low to high mortality in fish farms, causing economic losses for fish farmers. This study aimed to detect the presence of F. noatunensis orientalis using qPCR (real-time polymerase chain reaction) and to describe lesions caused by the bacterium in O. niloticus in Brazilian aquaculture. For this purpose, 360 fish from six fish farms (30 per farm) were sampled at two time points (n = 180 per sampling). Necropsies and histopathology were performed for lesion observation, in addition to qPCR and sequencing for detection and identification of Francisella species. Environmental data were collected using a multiparameter sonde YSI EXO2. All measured limnological variables were within the optimum range for cultivation of Nile tilapia. The major lesions present were melanization of the skin, splenomegaly, granulomas, and inflammatory cell responses. The prevalence of francisellosis varied from 0 to 86.66% between time periods and fish farms analyzed, and an outbreak was observed during the second sampling period. This study describes the prevalence of francisellosis in O. niloticus and reports that the lesions found are not exclusively associated with this bacterial disease.     

Ecological diversity of sediment rhizobacteria associated with Phragmites australis along a drainage canal in the Yellow River watershed

Journal of Soils and Sediments - Spatial distribution on a regional scale of the rhizobacterial communities of Phragmites australis stands was investigated along the Yellow River watershed, China....