Biocatalytic Regioselective O-acylation of Sesquiterpene Lactones from Chicory: A Pathway to Novel Ester Derivatives

We report the first biocatalytic modification of sesquiterpene lactones (STLs) found in the chicory plants, specifically lactucin (Lc), 11β,13-dihydrolactucin (DHLc), lactucopicrin (Lp), and 11β,13-dihydrolactucopicrin (DHLp). The selective O-acylation of their primary alcohol group was carried out by the lipase B from Candida antarctica (CAL-B) using various aliphatic vinyl esters as acyl donors. Perillyl alcohol, a simpler monoterpenoid, served as a model to set up the desired O-acetylation reaction by comparing the use of acetic acid and vinyl acetate as acyl donors. Similar conditions were then applied to DHLc, where five novel ester chains were selectively introduced onto the primary alcohol group, with conversions going from >99 % (acetate and propionate) to 69 % (octanoate). The synthesis of the corresponding O-acetyl esters of Lc, Lp, and DHLp was also successfully achieved with near-quantitative conversion. Molecular docking simulations were then performed to elucidate the preferred enzyme-substrate binding modes in the acylation reactions with STLs, as well as to understand their interactions with crucial amino acid residues at the active site. Our methodology enables the selective O-acylation of the primary alcohol group in four different STLs, offering possibilities for synthesizing novel derivatives with significant potential applications in pharmaceuticals or as biocontrol agents.

[Chiroptera and zoonosis: an emerging problem on all five continents]

Zoonosis is the cause of the vast majority of emerging diseases. Bats that occupy the second place in the mammal class play an important role. Whether they belong to the microchiroptera suborder or to the megachiroptera suborder, bats on all five continents have been implicated in transmission of numerous pathogens including not only viruses such as Lyssavirus (e.g. rabies), Hepanivirus (e.g. Hendra and Nipah virus) and recently coronavirus (e.g. SARS-like coronavirus and Ebola virus) but also fungus such as histoplasmosis. By modifying environmental conditions and encroaching on their biotope, human intervention has probably contributed to the introduction of chiropteras into an epidemiologic chain in which they previously had no place, thus promoting the emergence of new pathogens.

[Rapid immunochromatographic tests for detection of malaria: principles and strategies for use]

Malaria is a parasitological emergency requiring safe quick accurate diagnosis so that appropriate therapy can be implemented. A number of rapid diagnostic tests based on detection of HRP2 Ag, enzymes, LDH or aldolase are now available. However the use of these tests is restricted to trained, experienced staff in special situations. The purpose of this report is to describe the different tests on the market and clarify the limitations for their use.

Évaluation de la qualité de réalisation des tests de concordance ultime au lit du patient

As far as transfusions accidents are concerned, immunological causes are frequent. Pretransfusion Bedside Compatibility Tests (PBCT) are the last chance to avoid them. However low data are disponible on the quality their realisation is achieved. The aim of the study is to evaluate the quality level of achievement of these tests, in HIA Laveran Hospital (Marseille Armees, France). During 13 months, from november 2001 to december 2002, we systematically analysed PBCT after use (analysis rate 91%). Three kinds of errors have been noticed: Technical errors, understanding errors and both. Overall mistake rate was 10.4% (1632 tests analysed). In the same time, a complementary formation was dispensed to users responsible of misfits. This formation was successful, decreasing the overall mistake rate from 22.8% (november 2001) to 10.7% (december 2002). This study is an evidence of the importance to evaluate achievement quality of PBCT and shows how efficient can be simple correction methods.

Helicobacter pylori seroprevalence in asymptomatic pregnant women in France

The purpose of our study was to evaluate the incidence of Helicobacter pylori seropositivity in two different populations of asymptomatic pregnant women from different geographic origins during two separate time periods. A retrospective study of consecutive sera obtained from 169 and 302 asymptomatic pregnant women in 1990 and 1999, respectively, was carried out. The global H. pylori seroprevalences for 1990 and 1999 were 21.3 and 21.5% (where P is nonsignificant), respectively. For both periods the H. pylori seroprevalences were significantly higher in non-French pregnant women (66.6 and 50.6%) than in French pregnant women (18.7 and 11.2%) (P = 0.01 and 0.001, respectively). H. pylori seroprevalence in French pregnant women decreased significantly from the first period (18.7%) to the second one (11.2%) (P = 0.03).

[Correlation between sensitivity to fosfomycin and the presence of penicillinase PSE-1 in Pseudomonas aeruginosa]

A prospective survey was carried out during three three-weeks periods in May, October 1997 and October 1998 in 13 teaching hospitals. All non-repetitive isolates of P. aeruginosa collected were subject to serotypage and determination of the inhibiting minimal concentrations for ticarcillin, piperacillin, piperacillin + tazobactam, ceftazidime, imipenem, amikacin, ciprofloxacin and fosfomycin. Identification of the betalactamases and quantification of the cephalosporinase were done for the strains intermediate or resistant to ticarcillin. The most frequent serotypes were O: 6 (17%), O: 11 (13%), O: 1 (10%) and O: 12 (9%). Serotype O: 12 was the least susceptible to antibiotics except for fosfomycin. Whatever the serotype, 76% of P. aeruginosa strains with bla PSE-1 are susceptible to fosfomycin, when only 29.8% of non bla PSE-1 producing strains were susceptible to this antibiotic. Integron encoding bla PSE-1 could be implicated in susceptibility to fosfomycin of P. aeruginosa strains. The associations fosfomycin + imipenem or fosfomycin + ceftazidime could be proposed in case of infections due to P. aeruginosa O: 12.

[Scytalidium dimidiatum pseudodermatophyte, agent of superficial mycoses and phaehyphomycosis]

Scytalidium dimidiatum is a fungus found mainly in tropical and subtropical zones. Infection can cause a benign disease closely resembling dermatophytosis. In immunocompromised hosts, Scytalidium dimidiatum can also lead to phaehyphomycosis. Although awareness of these hyphae remains limited in developed countries, their incidence is growing due to increasing immigration and tourism. The rising incidence is well illustrated by three patients who presented onyxis and squamous-like manifestations on the arch of the foot upon returning from trips overseas and in whom various treatments were unsuccessful. In all three cases, culture in non-selective Sabouraud medium identified Scytalidium dimidiatum. These findings underline the need for laboratory testing before undertaking local or systemic treatment of onyxis especially since this pathogen can cause systemic disease. Study of ribosome genes showed that Scytalidium hyalinum is an homologous unpigmented mutant form of Scytalidium dimidatum. No antifungal agent has been effective for management of superficial manifestations and prevention depends mainly on the use of appropriate footwear in endemic areas.