Seasonal selection and resource dynamics in a seasonally polyphenic butterfly.

Seasonal polyphenisms are widespread in nature, yet the selective pressures responsible for their evolution remain poorly understood. Previous work has largely focussed either on the developmental regulation of seasonal polyphenisms or putative 'top-down' selective pressures such as predation that may have acted to drive phenotypic divergence. Much less is known about the influence of seasonal variation in resource availability or seasonal selection on optimal resource allocation. We studied seasonal variation in resource availability, uptake and allocation in Araschnia levana L., a butterfly species that exhibits a striking seasonal colour polyphenism consisting of predominantly orange 'spring form' adults and black-and-white 'summer form' adults. 'Spring form' individuals develop as larvae in the late summer, enter a pupal diapause in the fall and emerge in the spring, whereas 'summer form' individuals develop directly during the summer months. We find evidence for seasonal declines in host plant quality, and we identify similar reductions in resource uptake in late summer, 'spring form' larvae. Further, we report shifts in the body composition of diapausing 'spring form' pupae consistent with a physiological cost to overwintering. However, these differences do not translate into detectable differences in adult body composition. Instead, we find minor seasonal differences in adult body composition consistent with augmented flight capacity in 'summer form' adults. In comparison, we find much stronger signatures of sex-specific selection on patterns of resource uptake and allocation. Our results indicate that resource dynamics in A. levana are shaped by seasonal fluctuations in host plant nutrition, climatic conditions and intraspecific interactions.

[Vasoreactivity changes during extracorporeal circulation: effects of halogenated agents]. / Modifications de la vasoréactivité en CEC : influence des halogénés.

During cardiopulmonary bypass (CPB), endothelium is exposed to multiple disturbances leading to significant vasomotor tone and vascular systemic resistances (VSR) level modifications. Properties of endothelial function on vascular tone were summarized herein. According bibliographic findings, physiological and clinical impacts of respectively halogenated agents and CPB concerning vasomotor tone were reported. Main effects of halogenated agents administered through oxygenator during CPB were also identified. Usually when administered above one MAC, halogenated agents decreased VSR during hypothermic bypass. Once those mechanisms summarized, increase of halogenated agent's effects on VSR during normothermic CPB was postulated. Assuming that decrease of VSR could be deleterious favoring severe vasoplegia event, clinical experience of administration of isoflurane during CPB among more 4000 patients was retrospectively reported. Incidence of severe vasoplegia was established to 9.5 % in the studied population and this result was similar as others. More over predicting factors of severe vasoplegia were the same as previously reported : severity of preoperative clinical status according Euroscore, hemodynamical instability before induction of anesthesia, surgical procedure complexity and CPB duration. Absence of deleterious effects in SVR decrease when administering isoflurane during normothermic CPB was assumed but prospective comparative studies comparing effects of halogenated agents and other anesthetic agents are needed in order to confirm these findings.

The Acrolepiopsis assectella silk cocoon: kairomonal function and chemical characterisation.

Two soluble sericin-like polypeptides, B1 and B2, from leek moth (Acrolepiopsis assectella) cocoons trigger host-acceptance behaviour in the parasitoid, Diadromus pulchellus (Proc. Roy. Soc. London B 269 (2002) 1879). We found that these polypeptides were particularly cysteine-rich and lost their ability to trigger host-acceptance behaviour after being denatured and purified. This suggests that inter-disulphide bonds and the secondary structure of B1 and B2 are important for their biological activity. We also isolated six insoluble polypeptides (or polypeptides of low solubility) from A. assectella cocoons. At least four of these polypeptides triggered host-acceptance behaviour. The strongest responses were observed with P22, a light-chain fibroin or a seroin-peptide, and P100, a sericin-like polypeptide that is probably more strongly associated with the silk core than are B1 and B2. In conclusion, several polypeptides from different parts of the A. assectella silk-cocoon (the insoluble core and coating of the silk thread) are able to elicit host-acceptance behaviour in D. pulchellus females. These polypeptides belong to different silk protein families and are used as kairomones by this specialist parasitoid.

[French national survey of the use of monitoring devices during cardiopulmonary bypass in 2001]. / Enquête française sur les dispositifs de surveillance de la CEC en 2001.

OBJECTIVES: To study the different monitoring devices used during cardiopulmonary bypass (CPB) and to determine the factors, which may influence the choice of these equipments. STUDY DESIGN: Survey. METHODS: A postal questionnaire was send to the 66 French cardiac surgery centres. Results have been analysed about the economic status (public health service or private institution) and the business of the centre (less than 500, between 500 to 800 and more than 800 cardiopulmonary bypass/year). RESULTS: The rate of answer reached 73%. In 40% of centres, the cardiovascular perfusionist was not alone during the procedure. The percentage of centres using a checklist was 80%, a neurologic monitoring 42%, anaesthesia depth monitoring 40%, venous reservoir level detector 52%, arterial line bubble detector 38%, cardioplegia circuit bubble detector 6%, transoesophageal echocardiography 48%, pipe's temperature monitoring 90%; oxymetry 44%, capnography 25%, SvO2 98%, blood gas analysis outside the OR 46% and computer records 35%. No difference was observed between public and private institution for these latter devices. However, a significant difference was noticed among the low, intermediate and highly busy centres for the use of checklist, the EEG monitoring, the pipe and water circuit temperature monitoring, capnography and location of the biologic analysers. CONCLUSION: Equipments were not similar among the different French cardiac surgery centres. Furthermore, the French practice seems different from American, UK and Australian's one. These results highlight the need of establishing French guidelines, which are absent.

High-performance ion-pair chromatography method for simultaneous analysis of alliin, deoxyalliin, allicin and dipeptide precursors in garlic products using multiple mass spectrometry and UV detection.

The quality of garlic and garlic products is usually related to their alliin content and allicin release potential. Until now no analytical method was able to quantify simultaneously allicin, its direct precursor alliin (S-allyl-L-cysteine sulfoxide), SAC (S-allyl-L-cysteine) as well as various dipeptides that apparently serve as storage compounds in garlic. It is well known that all these intermediates are involved in the allicin biosynthetic pathway. A simple and rapid HPLC method suitable for routine analysis was developed using eluents containing an ion-pairing reagent. Particularly, heptanesulfonate as ion-pairing reagent guarantees a sufficient separation between alliin and the more retained dipeptides at very low pH. Allicin was eluted after 18 min on a 150 x 3 mm column. Synthetic reference compounds were characterized by the same chromatographic method using a diode-array UV detector and an ion trap mass spectrometer (electrospray ionization) in the multiple MS mode. In routine analysis of garlic bulbs, powders and other products, the diode-array detector is sufficient for a relevant quantification. Our method has been used in studies to improve the quality of garlic and its derived products.

Identification and synthesis of a kairomone mediating host location by two parasitoid species of the cassava mealybug Phenacoccus herreni.

Two encyrtid species, Acerophagus coccois and Aenasius vexans, parasitoids of the cassava mealybug Phenacoccus herreni use a contact kairomone from the body surface of their host as a host-location stimulant. The kairomone was synthesized and identified as O-caffeoylserine based on a combination of chromatographic methods. The synthetic compound was determined to be active.