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Here we describe the novel, multi-point Comet Interceptor mission. It is dedicated to the exploration of a little-processed long-period comet, possibly entering the inner Solar System for the first time, or to encounter an interstellar object originating at another star. The objectives of the mission are to address the following questions: What are the surface composition, shape, morphology, and structure of the target object? What is the composition of the gas and dust in the coma, its connection to the nucleus, and the nature of its interaction with the solar wind? The mission was proposed to the European Space Agency in 2018, and formally adopted by the agency in June 2022, for launch in 2029 together with the Ariel mission. Comet Interceptor will take advantage of the opportunity presented by ESA's F-Class call for fast, flexible, low-cost missions to which it was proposed. The call required a launch to a halo orbit around the Sun-Earth L2 point. The mission can take advantage of this placement to wait for the discovery of a suitable comet reachable with its minimum Δ V capability of 600  ms - 1 . Comet Interceptor will be unique in encountering and studying, at a nominal closest approach distance of 1000 km, a comet that represents a near-pristine sample of material from the formation of the Solar System. It will also add a capability that no previous cometary mission has had, which is to deploy two sub-probes - B1, provided by the Japanese space agency, JAXA, and B2 - that will follow different trajectories through the coma. While the main probe passes at a nominal 1000 km distance, probes B1 and B2 will follow different chords through the coma at distances of 850 km and 400 km, respectively. The result will be unique, simultaneous, spatially resolved information of the 3-dimensional properties of the target comet and its interaction with the space environment. We present the mission's science background leading to these objectives, as well as an overview of the scientific instruments, mission design, and schedule., Competing Interests: Competing InterestsThe authors declare no competing interests., (© The Author(s) 2024.)

ESA's Jupiter Icy Moons Explorer (JUICE) will provide a detailed investigation of the Jovian system in the 2030s, combining a suite of state-of-the-art instruments with an orbital tour tailored to maximise observing opportunities. We review the Jupiter science enabled by the JUICE mission, building on the legacy of discoveries from the Galileo, Cassini, and Juno missions, alongside ground- and space-based observatories. We focus on remote sensing of the climate, meteorology, and chemistry of the atmosphere and auroras from the cloud-forming weather layer, through the upper troposphere, into the stratosphere and ionosphere. The Jupiter orbital tour provides a wealth of opportunities for atmospheric and auroral science: global perspectives with its near-equatorial and inclined phases, sampling all phase angles from dayside to nightside, and investigating phenomena evolving on timescales from minutes to months. The remote sensing payload spans far-UV spectroscopy (50-210 nm), visible imaging (340-1080 nm), visible/near-infrared spectroscopy (0.49-5.56 μm), and sub-millimetre sounding (near 530-625 GHz and 1067-1275 GHz). This is coupled to radio, stellar, and solar occultation opportunities to explore the atmosphere at high vertical resolution; and radio and plasma wave measurements of electric discharges in the Jovian atmosphere and auroras. Cross-disciplinary scientific investigations enable JUICE to explore coupling processes in giant planet atmospheres, to show how the atmosphere is connected to (i) the deep circulation and composition of the hydrogen-dominated interior; and (ii) to the currents and charged particle environments of the external magnetosphere. JUICE will provide a comprehensive characterisation of the atmosphere and auroras of this archetypal giant planet., Competing Interests: Competing InterestsThe authors declare that they have no competing financial or non-financial interests to declare that are relevant to the content of this article., (© The Author(s) 2023.)

The environment of a comet is a fascinating and unique laboratory to study plasma processes and the formation of structures such as shocks and discontinuities from electron scales to ion scales and above. The European Space Agency's Rosetta mission collected data for more than two years, from the rendezvous with comet 67P/Churyumov-Gerasimenko in August 2014 until the final touch-down of the spacecraft end of September 2016. This escort phase spanned a large arc of the comet's orbit around the Sun, including its perihelion and corresponding to heliocentric distances between 3.8 AU and 1.24 AU. The length of the active mission together with this span in heliocentric and cometocentric distances make the Rosetta data set unique and much richer than sets obtained with previous cometary probes. Here, we review the results from the Rosetta mission that pertain to the plasma environment. We detail all known sources and losses of the plasma and typical processes within it. The findings from in-situ plasma measurements are complemented by remote observations of emissions from the plasma. Overviews of the methods and instruments used in the study are given as well as a short review of the Rosetta mission. The long duration of the Rosetta mission provides the opportunity to better understand how the importance of these processes changes depending on parameters like the outgassing rate and the solar wind conditions. We discuss how the shape and existence of large scale structures depend on these parameters and how the plasma within different regions of the plasma environment can be characterised. We end with a non-exhaustive list of still open questions, as well as suggestions on how to answer them in the future., Competing Interests: Competing InterestsThe authors declare no competing interests., (© The Author(s) 2022.)

Context: Collisions between cometary neutrals in the inner coma of a comet and cometary ions that have been picked up into the solar wind flow and return to the coma lead to the formation of a broad inner boundary known as a collisionopause. This boundary is produced by a combination of charge transfer and chemical reactions, both of which are important at the location of the collisionopause boundary. Four spacecraft measured ion densities and velocities in the inner region of comets, exploring the part of the coma where an ion-neutral collisionopause boundary is expected to form., Aims: The aims are to determine the dominant physics behind the formation of the ion-neutral collisionopause and to evaluate where this boundary has been observed by spacecraft., Methods: We evaluated observations from three spacecraft at four different comets to determine if a collisionopause boundary was observed based on the reported ion velocities. We compared the measured location of the ion-neutral collisionopause with measurements of the collision cross sections to evaluate whether chemistry or charge exchange are more important at the location where the collisionopause is observed., Results: Based on measurements of the cross sections for charge transfer and for chemical reactions, the boundary observed by Rosetta appears to be the location where chemistry becomes the more probable result of a collision between H 2 O and H 2 O + than charge exchange. Comparisons with ion observations made by Deep Space 1 at 19P/Borrelly and Giotto at 1P/Halley and 26P/Grigg-Skjellerup show that similar boundaries were observed at 19P/Borrelly and 1P/Halley. The ion composition measurements made by Giotto at Halley confirm that chemistry becomes more important inside of this boundary and that electron-ion dissociative recombination is a driver for the reported ion pileup boundary.

Since its detection in the aurorae of Jupiter approximately 30 years ago, the H 3 + ion has served as an invaluable probe of giant planet upper atmospheres. However, the vast majority of monitoring of planetary H 3 + radiation has followed from observations that rely on deriving parameters from column-integrated paths through the emitting layer. Here, we investigate the effects of density and temperature gradients along such paths on the measured H 3 + spectrum and its resulting interpretation. In a non-isothermal atmosphere, H 3 + column densities retrieved from such observations are found to represent a lower limit, reduced by 20% or more from the true atmospheric value. Global simulations of Uranus' ionosphere reveal that measured H 3 + temperature variations are often attributable to well-understood solar zenith angle effects rather than indications of real atmospheric variability. Finally, based on these insights, a preliminary method of deriving vertical temperature structure is demonstrated at Jupiter using model reproductions of electron density and H 3 + measurements. The sheer diversity and uncertainty of conditions in planetary atmospheres prohibits this work from providing blanket quantitative correction factors; nonetheless, we illustrate a few simple ways in which the already formidable utility of H 3 + observations in understanding planetary atmospheres can be enhanced. This article is part of a discussion meeting issue 'Advances in hydrogen molecular ions: H 3 + , H 5 + and beyond'.

When a weakly outgassing comet is sufficiently close to the Sun, the formation of an ionized coma results in solar wind mass loading and magnetic field draping around its nucleus. Using a 3D fully kinetic approach, we distill the components of a generalized Ohm's law and the effective electron equation of state directly from the self-consistently simulated electron dynamics and identify the driving physics in the various regions of the cometary plasma environment. Using the example of space plasmas, in particular multispecies cometary plasmas, we show how the description for the complex kinetic electron dynamics can be simplified through a simple effective closure, and identify where an isotropic single-electron fluid Ohm's law approximation can be used, and where it fails.

Background: Direct manipulation of the genome is a widespread technique for genetic studies and synthetic biology applications. The tyrosine and serine site-specific recombination systems of bacteriophages HK022 and ΦC31 are widely used for stable directional exchange and relocation of DNA sequences, making them valuable tools in these contexts. We have developed site-specific recombination tools that allow the direct selection of recombination events by embedding the attB site from each system within the β-lactamase resistance coding sequence (bla)., Results: The HK and ΦC31 tools were developed by placing the attB sites from each system into the signal peptide cleavage site coding sequence of bla. All possible open reading frames (ORFs) were inserted and tested for recombination efficiency and bla activity. Efficient recombination was observed for all tested ORFs (3 for HK, 6 for ΦC31) as shown through a cointegrate formation assay. The bla gene with the embedded attB site was functional for eight of the nine constructs tested., Conclusions: The HK/ΦC31 att-bla system offers a simple way to directly select recombination events, thus enhancing the use of site-specific recombination systems for carrying out precise, large-scale DNA manipulation, and adding useful tools to the genetics toolbox. We further show the power and flexibility of bla to be used as a reporter for recombination.

Integrons ensure a rapid and "on demand" response to environmental stresses driving bacterial adaptation. They are able to capture, store, and reorder functional gene cassettes due to site-specific recombination catalyzed by their integrase. Integrons can be either sedentary and chromosomally located or mobile when they are associated with transposons and plasmids. They are respectively called sedentary chromosomal integrons (SCIs) and mobile integrons (MIs). MIs are key players in the dissemination of antibiotic resistance genes. Here, we used in silico and in vivo approaches to study cassette excision dynamics in MIs and SCIs. We show that the orientation of cassette arrays relative to replication influences attC site folding and cassette excision by placing the recombinogenic strands of attC sites on either the leading or lagging strand template. We also demonstrate that stability of attC sites and their propensity to form recombinogenic structures also regulate cassette excision. We observe that cassette excision dynamics driven by these factors differ between MIs and SCIs. Cassettes with high excision rates are more commonly found on MIs, which favors their dissemination relative to SCIs. This is especially true for SCIs carried in the Vibrio genus, where maintenance of large cassette arrays and vertical transmission are crucial to serve as a reservoir of adaptive functions. These results expand the repertoire of known processes regulating integron recombination that were previously established and demonstrate that, in terms of cassette dynamics, a subtle trade-off between evolvability and genetic capacitance has been established in bacteria. IMPORTANCE The integron system confers upon bacteria a rapid adaptation capability in changing environments. Specifically, integrons are involved in the continuous emergence of bacteria resistant to almost all antibiotic treatments. The international situation is critical, and in 2050, the annual number of deaths caused by multiresistant bacteria could reach 10 million, exceeding the incidence of deaths related to cancer. It is crucial to increase our understanding of antibiotic resistance dissemination and therefore integron recombination dynamics to find new approaches to cope with the worldwide problem of multiresistance. Here, we studied the dynamics of recombination and dissemination of gene encoding cassettes carried on integrons. By combining in silico and in vivo analyses, we show that cassette excision is highly regulated by replication and by the intrinsic properties of cassette recombination sites. We also demonstrated differences in the dynamics of cassette recombination between mobile and sedentary chromosomal integrons (MIs and SCIs). For MIs, a high cassette recombination rate is favored and timed to conditions when generating diversity (upon which selection can act) allows for a rapid response to environmental conditions and stresses. In contrast, for SCIs, cassette excisions are less frequent, limiting cassette loss and ensuring a large pool of cassettes. We therefore confirm a role of SCIs as reservoirs of adaptive functions and demonstrate that the remarkable adaptive success of integron recombination system is due to its intricate regulation., (Copyright © 2017 Loot et al.)

Comets contain the best-preserved material from the beginning of our planetary system. Their nuclei and comae composition reveal clues about physical and chemical conditions during the early solar system when comets formed. ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) onboard the Rosetta spacecraft has measured the coma composition of comet 67P/Churyumov-Gerasimenko with well-sampled time resolution per rotation. Measurements were made over many comet rotation periods and a wide range of latitudes. These measurements show large fluctuations in composition in a heterogeneous coma that has diurnal and possibly seasonal variations in the major outgassing species: water, carbon monoxide, and carbon dioxide. These results indicate a complex coma-nucleus relationship where seasonal variations may be driven by temperature differences just below the comet surface., (Copyright © 2015, American Association for the Advancement of Science.)

Dam methylates GATC sequences in γ-proteobacteria genomes, regulating several cellular functions including replication. In Vibrio cholerae, which has two chromosomes, Dam is essential for viability, owing to its role in chr2 replication initiation. In this study, we isolated spontaneous mutants of V. cholerae that were able to survive the deletion of dam. In these mutants, homologous recombination and chromosome dimer resolution are essential, unless DNA mismatch repair is inactivated. Furthermore, the initiator of chr2 replication, RctB, is no longer required. We show that, instead, replication of chr2 is insured by spontaneous fusion with chr1 and piggybacking its replication machinery. We report that natural fusion of chr1 and chr2 occurred by two distinct recombination pathways: homologous recombination between repeated IS elements and site-specific recombination between dif sites. Lastly, we observed a preferential fusion of the two chromosomes in their terminus of replication., (© 2013 John Wiley & Sons Ltd.)

Toxin-antitoxin (TA) systems have been reported in the genomes of most bacterial species, and their role when located on the chromosome is still debated. TA systems are particularly abundant in the massive cassette arrays associated with chromosomal superintegrons (SI). Here, we describe the characterization of two superintegron cassettes encoding putative TA systems. The first is the phd-doc(SI) system identified in Vibrio cholerae N16961. We determined its distribution in 36 V. cholerae strains and among five V. metschnikovii strains. We show that this cassette, which is in position 72 of the V. cholerae N16961 cassette array, is functional, carries its own promoter, and is expressed from this location. Interestingly, the phd-doc(SI) system is unable to control its own expression, most likely due to the absence of any DNA-binding domain on the antitoxin. In addition, this SI system is able to cross talk with the canonical P1 phage system. The second cassette that we characterized is the ccd(Vfi) cassette found in the V. fischeri superintegron. We demonstrate that CcdB(Vfi) targets DNA-gyrase, as the canonical CcB(F) toxin, and that ccd(Vfi) regulates its expression in a fashion similar to the ccd(F) operon of the conjugative plasmid F. We also establish that this cassette is functional and expressed in its chromosomal context in V. fischeri CIP 103206T. We tested its functional interactions with the ccdAB(F) system and found that CcdA(Vfi) is specific for its associated CcdB(Vfi) and cannot prevent CcdB(F) toxicity. Based on these results, we discuss the possible biological functions of these TA systems in superintegrons.

Photochemically produced aerosols are common among the atmospheres of our solar system and beyond. Observations and models have shown that photochemical aerosols have direct consequences on atmospheric properties as well as important astrobiological ramifications, but the mechanisms involved in their formation remain unclear. Here we show that the formation of aerosols in Titan's upper atmosphere is directly related to ion processes, and we provide a complete interpretation of observed mass spectra by the Cassini instruments from small to large masses. Because all planetary atmospheres possess ionospheres, we anticipate that the mechanisms identified here will be efficient in other environments as well, modulated by the chemical complexity of each atmosphere.

Site-specific recombination catalyzed by tyrosine recombinases follows a common pathway consisting of two consecutive strand exchanges. The first strand exchange generates a Holliday junction (HJ), which is resolved by a second strand exchange. In integrons, attC sites recombine as folded single-stranded substrates. Only one of the two attC site strands, the bottom one, is efficiently bound and cleaved by the integrase during the insertion of gene cassettes at the double-stranded attI site. Due to the asymmetry of this complex, a second strand exchange on the attC bottom strand (bs) would form linearized abortive recombination products. We had proposed that HJ resolution would rely on an uncharacterized mechanism, probably replication. Using an attC site carried on a plasmid with each strand specifically tagged, we followed the destiny of each strand after recombination. We demonstrated that only one strand, the one carrying the attC bs, is exchanged. Furthermore, we show that the recombination products contain the attC site bs and its entire de novo synthesized complementary strand. Therefore, we demonstrate the replicative resolution of single-strand recombination in integrons and rule out the involvement of a second strand exchange of any kind in the attC×attI reaction.

Although bacteria with multipartite genomes are prevalent, our knowledge of the mechanisms maintaining their genome is very limited, and much remains to be learned about the structural and functional interrelationships of multiple chromosomes. Owing to its bi-chromosomal genome architecture and its importance in public health, Vibrio cholerae, the causative agent of cholera, has become a preferred model to study bacteria with multipartite genomes. However, most in vivo studies in V. cholerae have been hampered by its genome architecture, as it is difficult to give phenotypes to a specific chromosome. This difficulty was surmounted using a unique and powerful strategy based on massive rearrangement of prokaryotic genomes. We developed a site-specific recombination-based engineering tool, which allows targeted, oriented, and reciprocal DNA exchanges. Using this genetic tool, we obtained a panel of V. cholerae mutants with various genome configurations: one with a single chromosome, one with two chromosomes of equal size, and one with both chromosomes controlled by identical origins. We used these synthetic strains to address several biological questions--the specific case of the essentiality of Dam methylation in V. cholerae and the general question concerning bacteria carrying circular chromosomes--by looking at the effect of chromosome size on topological issues. In this article, we show that Dam, RctB, and ParA2/ParB2 are strictly essential for chrII origin maintenance, and we formally demonstrate that the formation of chromosome dimers increases exponentially with chromosome size., Competing Interests: The authors have declared that no competing interests exist.

The High Pathogenicity Island of Yersinia pseudotuberculosis IP32637 was previously shown to be horizontally transferable as part of a large chromosomal segment. We demonstrate here that at low temperature other chromosomal loci, as well as a non-mobilizable plasmid (pUC4K), are also transferable. This transfer, designated GDT4 (Generalized DNA Transfer at 4°C), required the presence of an IP32637 endogenous plasmid (pGDT4) that carries several mobile genetic elements and a conjugation machinery. We established that cure of this plasmid or inactivation of its sex pilus fully abrogates this process. Analysis of the mobilized pUC4K recovered from transconjugants revealed the insertion of one of the pGDT4-borne ISs, designated ISYps1, at different sites on the transferred plasmid molecules. This IS belongs to the IS6 family, which moves by replicative transposition, and thus could drive the formation of cointegrates between pGDT4 and the host chromosome and could mediate the transfer of chromosomal regions in an Hfr-like manner. In support of this model, we show that a suicide plasmid carrying ISYps1 is able to integrate itself, flanked by ISYps1 copies, at multiple locations into the Escherichia coli chromosome. Furthermore, we demonstrate the formation of RecA-independent cointegrates between the ISYps1-harboring plasmid and an ISYps1-free replicon, leading to the passive transfer of the non-conjugative plasmid. We thus demonstrate here a natural mechanism of horizontal gene exchange, which is less constrained and more powerful than the classical Hfr mechanism, as it only requires the presence of an IS6-type element on a conjugative replicon to drive the horizontal transfer of any large block of plasmid or chromosomal DNA. This natural mechanism of chromosome transfer, which occurs under conditions mimicking those found in the environment, may thus play a significant role in bacterial evolution, pathogenesis, and adaptation to new ecological niches., Competing Interests: The authors have declared that no competing interests exist.

Integrons are able to incorporate exogenous genes embedded in mobile cassettes, by a site-specific recombination mechanism. Gene cassettes are collected at the attI site, via an integrase mediated recombination between the cassette recombination site, attC, and the attI site. Interestingly, only three nucleotides are conserved between attC and attI. Here, we have determined the requirements of these in recombination, using the recombination machinery from the paradigmatic class 1 integron. We found that, strikingly, the only requirement is to have identical first nucleotide in the two partner sites, but not the nature of this nucleotide. Furthermore, we showed that the reaction is close to wild-type efficiency when one of the nucleotides in the second or third position is mutated in either the attC or the attI1 site, while identical mutations can have drastic effects when both sites are mutated, resulting in a dramatic decrease of recombination frequency compared to that of the wild-type sites. Finally, we tested the functional role of the amino acids predicted from structural data to interact with the cleavage site. We found that, if the recombination site triplets are tolerant to mutation, the amino acids interacting with them are extremely constrained.

We recently showed that cassette integration and deletion in integron platforms were occurring through unconventional site-specific recombination reactions involving only the bottom strand of attC sites. The lack of sequence conservation among attC sites led us to hypothesize that sequence-independent structural recognition determinants must exist within attC sites. The structural data obtained from a synaptic complex of the Vibrio cholerae integrase with the bottom strand of an attC site has shown the importance of extra helical bases (EHB) inside the stem-loop structure formed from the bottom strand. Here, we systematically determined the contribution of three structural elements common to all known single-stranded attC site recombination substrates (the EHBs, the unpaired central spacer (UCS), and the variable terminal structure (VTS)) to strand choice and recombination. Their roles have been evaluated in vivo in the attIxattC reaction context using the suicide conjugation assay we previously developed, but also in an attCxattC reaction using a deletion assay. Conjugation was used to deliver the attC sites in single-stranded form. Our results show that strand choice is primarily directed by the first EHB, but the presence of the two other EHBs also serves to increase this strand selection. We found that the structure of the central spacer is essential to achieve high level recombination of the bottom strand, suggesting a dual role for this structure in active site exclusion and for hindering the reverse reaction after the first strand exchange. Moreover, we have shown that the VTS has apparently no role in strand selectivity., Competing Interests: The authors have declared that no competing interests exist.

We evaluated the antimicrobial effect of antimicrobial peptides from frog skin belonging to the dermaseptin family against reference and clinical Neisseria gonorrhoeae strains, including penicillin-resistant strains. Dermaseptin S4 exhibited anti-N. gonorrhoeae activity against all strains with MICs ranging between 10 and 100 microg/mL. We then used derivatives of DS4 and determined the anti-N. gonorrhoeae activity of each of analogs. All the derivatives showed antimicrobial activity. Among the different molecules tested, we found that dermaseptins K4S4 (1-16)a and K4S4 (1-28) were the more potent to inhibit N. gonorrhoeae growth with MIC of 10 microg/mL against all strains.

From 1990 through 2002, 25,250 anonymous and free HIV tests were performed at a testing site, which carried out the majority (85%) of anonymous testing in Belgium. During the same period, approximately 7.3 million confidential tests were registered nationwide. The rate of new HIV infections diagnosed at the anonymous testing site was 11.1/1000 tests; it was significantly higher than the rate observed among confidential tests (relative risk = 7.41; P < 0.0001). New HIV cases diagnosed through anonymous testing include a higher proportion of young adults (42.0% versus 32.5% in confidential testing; P < 0.001) and a higher proportion of men who have sex with men (32.7% vs. 25.9% in confidential testing; P < 0.02). Anonymous and free HIV testing was particularly sought by persons with higher infection risk, and efficiently contributed to HIV diagnosis in this population. Anonymous and free testing should be and remain an accessible alternative integrated in HIV testing policies.

The occurrence of a clonal outbreak of serogroup W135 (of the electrophoretic type 37 [ET-37] clonal complex) meningococcal disease among Hajj pilgrims in 2000 has led to enhanced surveillance of the evolution of this particular serogroup, formerly considered rare, in invasive infections. Since the first case of meningococcal disease due to a serogroup W135 strain was detected in France in 1994, all isolates were characterized phenotypically. We further used phenotypic and genotypic approaches to type the 101 serogroup W135 strains isolated from patients with invasive meningococcal diseases in France in 2001 and 2002. Overall, 55% of these isolates had Hajj strain-related phenotypes (60 and 52% in 2001 and 2002, respectively), although only 45% belonged to the ET-37 clonal complex. Moreover, pulsed-field gel electrophoresis of the ET-37 clonal complex isolates showed that only 32% of the serogroup W135 isolates were indistinguishable from the 2000 Hajj-related strain. Our results suggest the continuous emergence of new genetic lineages of serogroup W135 independently of the 2000 global outbreak.

The clinical presentations of meningococcal diseases other than meningitis or meningococcemia may lead to erroneous diagnosis. Although several reports have described unusual meningococcal diseases, the Neisseria meningitidis strains involved in these forms have been poorly characterized. In this study, meningococcal arthritis and pericarditis were confirmed by isolation of N. meningitidis and/or detection of meningococcal DNA in synovial or pericardial fluid, respectively, and meningococcal pneumonia was detected by isolation of N. meningitidis from blood. From 1999 through 2002, meningococcal disease was bacteriologically confirmed in 26 cases of arthritis, 6 cases of pericarditis, and 33 cases of pneumonia by the National Reference Center for the Meningococci in Paris. We found a statistically significant association between strains of serogroup W135, mostly of the clonal complex ET-37, and arthritis. Pneumonia was most frequently diagnosed in patients aged >70 years, and 54.5% of the strains belonged to serogroup W135, although these strains had heterogeneous phenotypes. Bacteremia is a key step in the pathophysiology of meningococcal disease and precedes any form of invasive infection.

Infections due to Neisseria meningitidis are a major public health concern. In France, during 1999-2002, a total of 2167 clinical isolates of N. meningitidis from invasive infections were studied at the National Reference Center for Meningococci (Paris). Serogroup B strains were the most common (58%), followed by serogroup C strains (29%) and serogroup W135 strains (8%). Various phenotypes were observed, reflecting heterogeneity in the meningococcal population. Strains were susceptible to antibiotics currently used for treatment and chemoprophylaxis of meningococcal infections. However, the prevalence of meningococci with reduced susceptibility to penicillin is increasing. Such strains were heterogeneous and accounted for approximately 30% of isolates during this period, warranting continued surveillance of this phenomenon.

The gray mouse lemur Microcebus murinus is a rare example of a primate exhibiting daily torpor. In captive animals, we examined the metabolic rate during arousal from torpor and showed that this process involved nonshivering thermogenesis (NST). Under thermoneutrality (28 degrees C), warming-up from daily torpor (body temperature <33 degrees C) involved a rapid (<5 min) increase of O(2) consumption that was proportional to the depth of torpor (n = 8). The injection of a beta-adrenergic agonist (isoproterenol) known to elicit NST induced a dose-dependent increase in metabolic rate (n = 8). Moreover, maximum thermogenesis was increased by cold exposure. For the first time in this species, anatomic and histological examination using an antibody against uncoupling protein (UCP) specifically demonstrated the presence of brown fat. With the use of Western blotting with the same antibody, we showed a likely increase in UCP expression after cold exposure, suggesting that NST is also used to survive low ambient temperatures in this tropical species.

The purpose of this study was to identify professional factors related to benzene exposure and to deduce suitable safety measures. Atmospheric benzene, urinary muconic acid (tt-MA) and leukocyte alkaline phosphatase activity (LAPA) were evaluated among 66 car mechanics, 34 road tanker drivers, and 28 nonexposed workers. Professional and medical questionnaires were filled in at the same time. Atmospheric benzene was significantly higher among road tanker drivers than among car mechanics. The arithmetic mean +/- SD, median, and geometric mean values were, respectively, 0.48 +/- 1.49, 0.14, and 0.06 mg/m3 among car mechanics and 1.88 +/- 4.18, 0.68, and 0.65 mg/m3 among road tanker drivers. In the latter case the increase was caused by transport of unleaded petrol and correlated with the volume of the tank. Among car mechanics, tobacco smoking, windy conditions, dismantling of petrol filters, and handling of petrol increased atmospheric benzene levels. Urinary muconic acid was increased significantly among car mechanics (148 +/- 137, 127, and 111 micrograms/g) and among road tanker drivers (309 +/- 420, 137, and 151 micrograms/g) as compared with the controls (49 +/- 46, 33, and 33 micrograms/g). Among road tanker drivers, alcohol intake and transportation of unleaded petrol increased the excretion of muconic acid, which was also directly related to the volume of the tank. Among car mechanics, professional factors (dismantling of petrol filters, handling of and washing of hands with petrol) and nonprofessional factors (tobacco smoking and damaged skin on the hands and forearms) increased muconic acid excretion. In the control group, tobacco smoking increased its excretion. LAPA was not significantly modified among exposed workers. There was a weak but significant linear correlation between LAPA and muconic acid. These results suggest that to reduce exposure to benzene in unleaded petrol, individual and collective safety measures should be imposed in both occupations.