How natural infection by Nosema ceranae causes honeybee colony collapse.

In recent years, honeybees (Apis mellifera) have been strangely disappearing from their hives, and strong colonies have suddenly become weak and died. The precise aetiology underlying the disappearance of the bees remains a mystery. However, during the same period, Nosema ceranae, a microsporidium of the Asian bee Apis cerana, seems to have colonized A. mellifera, and it's now frequently detected all over the world in both healthy and weak honeybee colonies. For first time, we show that natural N. ceranae infection can cause the sudden collapse of bee colonies, establishing a direct correlation between N. ceranae infection and the death of honeybee colonies under field conditions. Signs of colony weakness were not evident until the queen could no longer replace the loss of the infected bees. The long asymptomatic incubation period can explain the absence of evident symptoms prior to colony collapse. Furthermore, our results demonstrate that healthy colonies near to an infected one can also become infected, and that N. ceranae infection can be controlled with a specific antibiotic, fumagillin. Moreover, the administration of 120 mg of fumagillin has proven to eliminate the infection, but it cannot avoid reinfection after 6 months. We provide Koch's postulates between N. ceranae infection and a syndrome with a long incubation period involving continuous death of adult bees, non-stop brood rearing by the bees and colony loss in winter or early spring despite the presence of sufficient remaining pollen and honey.

Enantiomeric separation of chiral sulfoxides by supercritical fluid chromatography.

The application of supercritical fluid chromatography (SFC) to the enantiomeric separation of several chiral sulfoxides belonging to the family of the substituted benzimidazoles, including omeprazole, lansoprazole, pantoprazole, rabeprazole, oxfendazole and ricobendazole, is presented in this work. The column employed was Chiralpak AD and the effect of different chromatographic conditions was studied. The results obtained showed that all the compounds can be enantiomerically resolved using SFC, with resolutions higher than 2 and analysis times that in most cases were lower than 10 min. Alcohol type modifiers provided the best results, with ricobendazole, oxfendazole, and omeprazole showing the highest retentions and resolutions. Study of the temperature effect revealed that, in general, the isoelution temperature was above the temperatures assayed, except in the cases of omeprazole, lansoprazole, and oxfendazole with ethanol as modifier and pantoprazole with acetonitrile. Enthalpy-entropy compensation could also be demonstrated for the retention of the first and second eluted enantiomers as well as for the selectivity, with compensation temperatures of 25 degrees C, 45 degrees C, and 83 degrees C, respectively. Reversal of elution on change of the organic modifier was only observed for omeprazole using 2-propanol.

Determination of impurities in pesticides and their degradation products formed during the wine-making process by solid-phase extraction and gas chromatography with detection by electron ionization mass spectrometry. II. Bromopropylate, trichlorphon, parathion-methyl and tebuconazole.

The presence of degradation products of bromopropylate, trichlorphon, parathion-methyl and tebuconazole in white and red wines elaborated from musts spiked with commercial formulations of the pesticides was studied. Must and wine were subjected to solid-phase extraction followed by gas chromatography with electron ionization mass spectrometric detection. Alpha-bromophenylphenylmethanol, aminoparathion, acetylaminoparathion-oxon and dichlorvos have been identified as degradation products of bromopropylate, parathion-methyl and trichlorphon in wines, respectively. Moreover, the presence of additives and impurities of the formulations in elaborated wines has also been found.

Chiral separation of omeprazole and several related benzimidazoles using supercritical fluid chromatography.

A study of the enantiomeric separation of omeprazole and several related benzimidazoles, using supercritical fluid chromatography (SFC), on the amylose based column Chiralpak AD is presented in this work. The effect of the organic modifier as well as temperature on the retention and enantioresolution was investigated. Alcohol-type modifiers provided the best results, allowing the enantiomeric separation of all the compounds studied with resolutions that were in most cases higher than 2, and analysis times lower than 10 minutes. An investigation of the temperature effect revealed that the isoelution temperature was below the working temperature range in only two cases, and hence it was better to work at the highest temperature permitted.

Determination of impurities in pesticides and their degradation products formed during the wine-making process by solid-phase extraction and gas chromatography with detection by electron impact mass spectrometry. I. Vinclozoline, procymidone and fenitrothion.

The presence of degradation products of vinclozoline, procymidone and fenitrothion, and of impurities from their commercial formulations, was studied in white and red wines elaborated from spiked must. After solid-phase extraction the nature of the residues was established by gas chromatography with mass spectrometric detection. The structures of several degradation products and impurities are discussed and elucidated on the basis of their electron impact spectra. In elaborated wines the concentrations of the degradation products and impurities are lower than those of the original active ingredients. Aminofenitrothion and acetylamino-formyl-fenitrothion-oxon are the main residues of fenitrothion in wine. For dicarboximides, an alcohol derivative of vinclozoline was found in addition to 3,5-dichloroaniline.