New type of Sesiidae sex pheromone identified from the hornet moth Sesia apiformis.

Two components of the female-produced sex pheromone of the hornet moth, Sesia apiformis, were identified as (3Z,13Z)-octadeca-3,13-dien-1-ol (3Z,13Z-18:OH) and (2E,13Z)-octadeca-2,13-dienal (2E,13Z-18:Al), a pheromone structure new in Sesiidae. Pooled gland extracts showed the two major compounds in a proportion of ca. 2:3, while SPME-investigations on single calling females revealed a ratio of ca. 1:7. Although the single compounds were not attractive, a 2:3 mixture proved to be highly active towards males in field tests. Small amounts of (2E,13Z)-octadecadienol (2E,13Z-18:OH) were found in the sex pheromone gland of females, however, the biological significance of the compound remains unclear. Methyl sulfide was found to readily react with 2-alkenals, providing an effective new method for the characterization of this type of compound upon GC/MS. The derivatives, 1,1,3-tris(methylthio)alkanes, are the products of the addition of methyl sulfide to the double bond and the transformation of the carbonyl group into the corresponding bis(methylthio)acetal. The mass spectra of these compounds are characterized by diagnostic signals at m/z 107 and/or m/z 121. These fragments represent the first carbon unit or the first two carbon units of the derivative, respectively. The parent signal in the spectra of thiomethyl derivatives of 2-alkenals showing no other double bonds is represented by m/z M+ - 121, formed upon loss of the first two carbon units. By employing a solution of methyl sulfide in dimethyl sulfide, the double bond positions in 2E,13Z-18:Al could be fully characterized by GC/MS.

A chiral sex pheromone system in the pea midge, Contarinia pisi.

The sex pheromone of the pea midge consists of 2-acetoxytridecane, (2S,11S)-diacetoxytridecane and (2S,12S)-diacetoxytridecane. The responses of male pea midges to the corresponding stereoisomers of (2S,11S)-diacetoxytridecane and (2S,12S)-diacetoxytridecane were tested in field trapping experiments and by electroantennographic recordings. When added at 20% of the pheromone component to the sex pheromone blend, the (2S,11R)- and (2R,11S)-stereoisomers of (2S,11S)-diacetoxytridecane, were shown to have a strong inhibitory effect on male attraction in the field. At the same dose, (2R,11R)-diacetoxytridecane, (2R,12R)-diacetoxytridecane, and meso-2,12-diacetoxytridecane, did not have a significant effect on male behavior. It was also shown that substitution of either (2S,11S)-diacetoxytridecane or (2S,12S)-diacetoxytridecane with the related stereoisomers reduced trap catches to the level of blank traps. The electroantennographic recordings showed similar dose-response curves for the pheromone components and the stereoisomers shown to have an inhibitory effect. It seems likely that male antennae have receptors for bothpheromone components and for inhibitory stereoisomers. Scanning electron microscopy and transmission electron microscopy of the antennae revealed three types of sensilla involved in chemoreception: sensilla circumfila, sensilla trichodea, and sensilla coeloconica. The sensilla circumfila and trichodea are both innervated by two sensory cells, whereas the sensilla coeloconica are innervated by four to five cells.

[Nosocomial epidemic outbreak of diarrhea from Clostridium difficile. Comparative study of diarrhea associated with the use of antibiotics]. / Brote epidémico nosocomial de diarrea por Clostridium difficile. Estudio comparativo con la diarrea asociada al uso de antibióticos.

BACKGROUND: Clostridium difficile is considered as one of the principal enteropathogens of nosocomial origin in developed countries in the last decade. No nosocomial outbreaks have been described in Spain. METHODS: A descriptive study of a nosocomial outbreak of diarrhea by C. difficile (DCD) which was produced during two months in a general hospital of 250 beds was carried out. The risk factors, clinical and analytical characteristics were compared with the cases of diarrhea associated to the use of antibiotics (DAA) produced during the same period. RESULTS: Of the 23 diarrheas studied, 17 (74%) corresponded to DAA and 6 (26%) to DCD, four of which were of nosocomial origin and were detected in the department of Nephrology. The incidence of DAA was 44/1000 patients who received antibiotic treatment per month and the incidence of DCD was 15.5/1000 patients/month. The patients with DAA received a mean of 1.82 antimicrobians per patient and in DCD 2.16 per patient (p: NS). The only differences found between DAA and DCD were: length of the symptoms (16.5 days in DCD, 8.5 days in DAA, p < 0.01) and the presence of blood in the feces (66.6% in DCD and 0 in DAA p < 0.01). No differences were observed in age, sex, base disease, mucous diarrhea, fever, mortality, high VSG and leucocytosis. Surveillance and control measures were effective in combating the epidemic outbreak. CONCLUSIONS: The diagnosis of diarrhea by C. difficile requires a high index of suspicion given the difficulty in differentiating the same from diarrhea associated to antibiotic use. The clinical profile and risk factors do not differ to those described in other geographic areas. The isolation and/or detection of toxins of C. difficile is recommended in patients submitted to antibiotic treatment and diarrhea of more than 72 hours of evolution.