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Standard climate projections represent future volcanic eruptions by a constant forcing inferred from 1850-2014 volcanic forcing. Using the latest ice-core and satellite records to design stochastic eruption scenarios, we show that there is a 95% probability that explosive eruptions could emit more sulfur dioxide (SO) into the stratosphere over 2015-2100 than current standard climate projections (i.e., ScenarioMIP). Our simulations using the UK Earth System Model with interactive stratospheric aerosols show that for a median future eruption scenario, the 2015-2100 average global-mean stratospheric aerosol optical depth (SAOD) is double that used in ScenarioMIP, with small-magnitude eruptions (< 3 Tg of SO) contributing 50% to SAOD perturbations. We show that volcanic effects on large-scale climate indicators, including global surface temperature, sea level and sea ice extent, are underestimated in ScenarioMIP because current climate projections do not fully account for the recurrent frequency of volcanic eruptions of different magnitudes.

Relating the mass eruption rate (MER) of explosive eruptions to column height in the atmosphere is key to reconstructing past eruptions and forecasting volcanic hazards. Using 134 eruptive events from the Independent Volcanic Eruption Source Parameter Archive (IVESPA v1.0), we explore the canonical MER-height relationship for four measures of column height: spreading level, sulfur dioxide height, and top height from both directly observed plumes and those reconstructed from deposits. These relationships show significant differences and should be chosen carefully for operational and research applications. The roles of atmospheric stratification, wind, and humidity remain challenging to assess across the large range of eruptive conditions in this database, ultimately resulting in empirical relationships outperforming analytical models that account for atmospheric conditions. This finding reveals the complexity of the height-MER relation that is difficult to constrain based on available heterogeneous observations, which reinforces the need for improved datasets to develop eruptive column models.

Buruli ulcer (BU) disease, caused by Mycobacterium ulcerans, is a major public health problem in Côte d'Ivoire. Until now, the mode of BU transmission was unknown, but recent studies implicate aquatic Heteroptera in the chain of transmission. This study was launched in Côte d'Ivoire to search for specific genetic markers for M. ulcerans in these bugs, including the insertion sequence IS2404 and ketoreductase (Kr), both involved in the synthesis of mycolactone, a toxin produced by these mycobacteria. Samples of aquatic Heteroptera were collected monthly with deep nets from ponds near villages in the health districts of Dabou and Tiassalé. After identification and enumeration of the bugs, batches of the same taxon underwent real-time PCR to search for the IS2404 target and Kr. Saliva of 69 specimens of Diplonychus sp randomly selected in the samples was also analyzed by PCR. In all, 283 single-taxon batches were created. Thus, PCR identified 26 batches belonging to the families of Belostomatidae, Naucoridae, Corixidae, Ranatridae, and Nepidae as positive for both targets. The IS2404 insertion sequence and Kr were present in 6 of the 69 samples analyzed in the saliva of Diplonychus sp. These aquatic Heteroptera suspected of infection by M. ulcerans might release it into the environment because of their ability to fly. They might thus be the source of human contamination.

According to recommendations of the 6th WHO Advisory Committee on Buruli ulcer, directly observed treatment with the combination of rifampin and streptomycin, administered daily for 8 weeks, was recommended to 310 patients diagnosed with Buruli ulcer in Pobè, Bénin. Among the 224 (72%) eligible patients for whom treatment was initiated, 215 (96%) were categorized as treatment successes, and 9, including 1 death and 8 losses to follow-up, were treatment failures. Of the 215 successfully treated patients, 102 (47%) were treated exclusively with antibiotics and 113 (53%) were treated with antibiotics plus surgical excision and skin grafting. The size of lesions at treatment initiation was the major factor associated with surgical intervention: 73% of patients with lesions of >15 cm in diameter underwent surgery, whereas only 17% of patients with lesions of Mycobacterium ulcerans disease, 2 among the 107 patients treated only with antibiotics and 1 among the 108 patients treated with antibiotics plus surgery. We conclude that the WHO-recommended streptomycin-rifampin combination is highly efficacious for treating M. ulcerans disease. Chemotherapy alone was successful in achieving cure in 47% of cases and was particularly effective against ulcers of less than 5 cm in diameter.

Purpose: We previously generated a mouse monoclonal antibody (mAb) specific for the tumor-associated GD2 ganglioside antigen. Here, we describe the development of a chimeric anti-GD2 mAb for more effective tumor immunotherapy.Experimental Design: We cloned the cDNA encoding the immunoglobulin light and heavy chains of the 60C3 anti-GD2 mAb, and constructed chimeric genes by linking the cDNA fragments of the variable regions of the murine light and heavy chains to cDNA fragments of the human κ and γ1 constant regions, respectively.Results: The resultant chimeric anti-GD2 mAb, c.60C3, showed identical binding affinity and specificity to that of its murine counterpart. Both c.60C3 and 60C3 were rapidly internalized by tumor cells at 37°C. When human serum and human natural killer cells were used as effectors in complement-mediated cytotoxicity and antibody-dependent cell cytotoxicity, respectively, c.60C3 was more effective in killing GD2-expressing tumor cells. However, c.60C3 was ineffective at inducing cell death by apoptosis, although binding of 60C3 induced apoptotic death in vitro. In an in vivo, GD2-expressing, syngeneic tumor model, i.v. injection of c.60C3, but not of 60C3, significantly suppressed tumor growth in mice (P < 0.0005).Conclusion: Immune effector functions mediated by this antibody and its potentially reduced immunogenicity make chimeric c.60C3 a promising therapeutic agent against neuroectodermic tumors.

En conclusion Nos resultats suggerent un modele complexe decrivant la strategie d’infiltration des lymphocytes T cytotoxiques dans une tumeur solide (Figure 1). Les lymphocytes T colonisent la tumeur par les vaisseaux peripheriques, et ils s’arretent au contact des cellules tumorales dont ils induisent la mort. Lorsque les cellules tumorales dans ces regions peripheriques sont eliminees, les lymphocytes T reprennent leur mobilite a la recherche de cellules tumorales vivantes au sein des regions plus profondes de la tumeur. Cette repetition sequentielle « cytotoxicite statique/mobilite » aboutit a l’infiltration et l’elimination progressive de la tumeur, depuis la peripherie vers le centre. ◊ Stepwise strategy adopted by cytotoxic T cells to eliminate solid tumors

The severe skin-destructive disease caused by Mycobacterium ulcerans, named Buruli ulcer, is the third most important mycobacterial disease in humans after tuberculosis and leprosy. Recently we demonstrated that M. ulcerans could colonize the salivary glands of the water bug, Naucoris cimicoides. In this study, we report that M. ulcerans may be delivered from the digested prey aspirate to the coelomic cavity via a unique headspace, the head capsule (HC). During the infected meal, we observed that M. ulcerans clusters adhered to the stylets that were retracted in the HC at the end of the meal. M. ulcerans was able to translocate from the HC to the coelomic cavity where it is phagocytosed by the plasmatocytes. These cells are subverted as shuttle cells and deliver M. ulcerans to the salivary glands. At this early stage of its parasitic life style, two other important features of M. ulcerans can be documented: first, mycolactone is not required for translocation of M. ulcerans into the HC, in contrast to the next step, colonization of the salivary glands; second, M. ulcerans clusters bind a member of the serpin protein family present in the salivary gland homogenate.

Mycobacterium ulcerans was first identified as the causative agent of Buruli ulcer; this cutaneous tissue-destructive process represents the third most important mycobacterial disease in humans after tuberculosis and leprosy. More recently other life traits were documented. M. ulcerans is mainly detected in humid tropical zones as part of a complex ecosystem comprising algae, aquatic insect predators of the genus Naucoris, and very likely their vegetarian preys. Coelomic plasmatocytes could be the first cells of Naucoris cimicoides to be involved in the infection process, acting as shuttle cells that deliver M. ulcerans to the salivary glands as suggested by both in vitro and in vivo approaches. Furthermore, a key element for the early and long-term establishment of M. ulcerans in Naucoridae is demonstrated by the fact that only mycolactone toxin-producing M. ulcerans isolates are able to invade the salivary glands, a site where they proliferate. Later, the raptorial legs of Naucoris are covered by M. ulcerans-containing material that displays features of biofilms.

Mycobacterium ulcerans is the causative agent of Buruli ulcer, one of the most common mycobacterial diseases of humans. Recent studies have implicated aquatic insects in the transmission of this pathogen, but the contributions of other elements of the environment remain largely unknown. We report here that crude extracts from two green algae added to the BACTEC 7H12B culture medium halved the doubling time of M. ulcerans and promoted biofilm formation. Using the 7H12B medium, modified by the addition of the algal extract, and immunomagnetic separation, we also demonstrate that M. ulcerans is associated with aquatic plants in an area of the Ivory Coast where Buruli ulcer is endemic. Genotype analysis showed that plant-associated M. ulcerans had the same profile as isolates recovered in the same region from both aquatic insects and clinical specimens. These observations implicate aquatic plants as a reservoir of M. ulcerans and add a new potential link in the chain of transmission of M. ulcerans to humans.

The analysis of two phosphate ester additives found in the formulation of metalworking fluids is reported. These are isopropylated triarylphosphates which are used as extreme pressure additives and polyethoxylated phosphates with emulgating properties. The additives are first analyzed as raw materials; then within a typical lubricant where they are identified and quantified. The methodology makes use of chromatography (TLC, HPLC, SPE) and NMR spectroscopy ( 1 H, 13 C, 31 P). The valuable contribution of 31 P NMR to the deformulation of such products is particularly emphasized.

Despite the weak immunogenicity of gangliosides, a limited number of highly specific murine monoclonal antibodies (MAbs) were elicited. This study investigated the reactivity and the structure of the VH and V kappa genes of nine hybridomas obtained from independent fusions producing antibodies against disialogangliosides GD2 and GD3 and their O-acetylated derivatives. These antibodies depended on four types of V kappa genes. They were also encoded by VH genes of the J558 family (5 out of 9) and occasionally by VH genes of the S107, 7183, and 3609 families, rearranged with a variety of DH and JH genes. The 8B6 and 7H2 MAbs specific for GD2-O-acetylated, respectively, used the VH gene of the S107 and 7183 families. The length of H chain CDR3 ranged from 8 to 11 amino acids. A set of S107 and 3609 germline genes closed from A/J murine fetal liver and matched with the VH segment of hybridomas 8B6 and 10B8 revealed somatic mutations. Although the relative number of sequences does not preclude any formal conclusions regarding the preferential use of V genes in the immune recognition of carbohydrate structures, our results clearly indicate that MAbs directed to very similar structures as GD2 and GD3 were encoded by different VH and V kappa genes.

O-Acetyl-GD2 ganglioside is suitable antigen for tumor immunotherapy with specific therapeutic antibody. Here, we investigate the anti-tumor activity of O-acetyl-GD2-specific monoclonal antibody 8B6 on O-acetyl-GD2-positive tumor cells. The results indicated that mAb 8B6 induced growth inhibition of O-acetyl-GD2-expressing tumor cell lines in vitro with features of cell cycle arrest and apoptosis. Monoclonal antibody 8B6 treatment was also very effective in suppression of tumor growth in mice by reducing the proliferation index and increasing the apoptotic index. Such a study represents a useful framework to optimize immunotherapy with O-acetyl-GD2-specific antibody in combination with chemotherapeutic agents.

International audience; Inhibiting the growth of tumor vasculature represents one of the relevant strategies against tumor progression. Between all the different pro-angiogenic molecular targets, plasma membrane glycosphingolipids have been under-investigated. In this present study, we explore the anti-angiogenic therapeutic advantage of a tumor immunotherapy targeting the globotriaosylceramide Gb3. In this purpose, a monoclonal antibody against Gb3, named 3E2 was developed and characterized. We first demonstrate that Gb3 is over-expressed in proliferative endothelial cells relative to quiescent cells. Then, we demonstrate that 3E2 inhibits endothelial cell proliferation in vitro by slowing endothelial cell proliferation and by increasing mitosis duration. Antibody 3E2 is further effective in inhibiting ex vivo angiogenesis in aorta ring assays. Moreover, 3E2 treatment inhibits NXS2 neuroblastoma development and liver metastases spreading in A/J mice. Immunohistology examination of the NXS2 metastases shows that only endothelial cells, but not cancer cells express Gb3. Finally, 3E2 treatment diminishes tumor vessels density, proving a specific therapeutic action of our monoclonal antibody to tumor vasculature. Our study demonstrates that Gb3 is a viable alternative target for immunotherapy and angiogenesis inhibition. © 2012 Desselle et al.

To the Editor: Buruli ulcer disease (BU) is a necrotizing skin disease caused by Mycobacterium ulcerans that affects mostly children in humid, tropical areas (1). The exact mode of M. ulcerans transmission remains unclear, although the role of water bugs has been supported by various observations and experimental studies (2,3). We report the identification of a new BU-endemic area in Cameroon, the Bankim district, and specify ecologic and clinical characteristics of M. ulcerans infection in this area. These characteristics hint at the possible role of environmental changes (building of a dam several years ago) in the expansion of BU in this area. Since 1969, only 1 BU-endemic area in Cameroon has been described: the Nyong River basin, where equatorial forest predominates (4). In 2004, clinically suspected cases of BU in the district of Bankim have been reported (5). This region differs from the first BU-endemic area by geography and climate. Representing a transition between forested south and savanna north, this area has benefited from the building of a dam on the Mape River in 1989, which created an artificial lake of 3.2 billion m3 capacity. From January 2007 through June 2009, all cases of skin lesions evocative of active BU were recorded as BU probable cases according to World Health Organization guidelines (6). During this period, 195 clinically suspected cases were reported from the Bankim health district (Figure). The overall median age for these 195 patients was 19.5 years (interquartile range 10–37 years). No significant difference in age was found according to gender, but a significant trend of decreasing overall median age was found (20 years in 2007 to 12 years in 2009. The most frequent type of lesion was ulcer. Since March 2009, the Centre Pasteur of Cameroon has performed laboratory confirmation for suspected BU cases: microscopic examination for acid-fast bacilli, culture, and M. ulcerans DNA detection by PCR (6). From April through June 2009, of 34 consecutive samples tested in the reference laboratory, 10 were positive for M. ulcerans by at least microscopy and PCR. Figure Distribution of Buruli ulcer (BU) patients reported January 2007–June 2009, and of water bodies with aquatic bugs harboring Mycobacterium ulcerans, Cameroon. Inset, Bankim area. A color version of this figure is available online (www.cdc.gov/EID/content/17/3/551-F.htm ... Whether BU is emerging in Bankim or is just a newly recognized preexisting disease is difficult to establish. However, that the incidence of BU in the region is increasing is unquestionable. The decreasing median age of patients since 2007 might be consistent with emergence of BU as a new disease in Bankim. This observation could suggest either an increasing level of acquired immunity in the population, leading to protection correlated with age, or the expansion of risky sites for human infection with M. ulcerans. During 1 week in January 2008, water bugs were collected from the artificial lake and water bodies located within or close to each community. A previously described sampling method was used (2). To detect M. ulcerans DNA, we pooled the insects per family in groups of up to 10. Moreover, 99 members of the families Belostomatidae and Naucoridae were kept alive for saliva collection (2). The DNA of insect pool homogenized tissues and individual saliva samples were purified. We then searched for M. ulcerans molecular signatures (2). Among 1,349 insect specimens, 8 from the aquatic Heteroptera families were identified, and 12 (5%) of 244 insect pools were M. ulcerans positive. M. ulcerans–positive saliva was found in 11 (18%) of 61 insects in the family Belostomatidae and in 3 (8%) of 38 in the family Naucoridae. Water bodies where M. ulcerans–positive insects were collected are shown in the Figure. The emergence of BU may be a consequence of the marked changes in the environment caused by the building of the dam. Elsewhere, human environmental modifications such as construction of dams have been linked with increased incidence of BU (1). The main visible environmental effect is the large amount of flooded farmland. According to the seasons, the reservoir margins change the milieu of swamps and meadows. All these modifications affect plant and animal resources in the reservoir area by favoring rapid growth of aquatic macrophyte populations during reservoir filling, thus providing breeding sites for insects and leading to the extinction of area-endemic species and creation of new niches (7). These changes might favor development of M. ulcerans in biofilms on aquatic plants, which are then ingested by herbivorous animals, which are further prey for water bug predators, hosts, and possible vectors of M. ulcerans (8,9). The water bugs that were most frequently trapped and colonized by M. ulcerans (families Belostomatidae, Naucoridae, Nepidae, Notonectidae) are carnivorous and able to bite humans (10). Our study confirms expansion of BU in Cameroon. To facilitate detection of new BU foci, and to improve patient treatment (medical, surgical, rehabilitative), health care workers involved in tuberculosis/leprosy control programs should be educated about BU.

Background Buruli ulcer, the third mycobacterial disease after tuberculosis and leprosy, is caused by the environmental mycobacterium M. ulcerans. Various modes of transmission have been suspected for this disease, with no general consensus acceptance for any of them up to now. Since laboratory models demonstrated the ability of water bugs to transmit M. ulcerans, a particular attention is focused on the transmission of the bacilli by water bugs as hosts and vectors. However, it is only through detailed knowledge of the biodiversity and ecology of water bugs that the importance of this mode of transmission can be fully assessed. It is the objective of the work here to decipher the role of water bugs in M. ulcerans ecology and transmission, based on large-scale field studies. Methodology/Principal Findings The distribution of M. ulcerans-hosting water bugs was monitored on previously unprecedented time and space scales: a total of 7,407 water bugs, belonging to large number of different families, were collected over one year, in Buruli ulcer endemic and non endemic areas in central Cameroon. This study demonstrated the presence of M. ulcerans in insect saliva. In addition, the field results provided a full picture of the ecology of transmission in terms of biodiversity and detailed specification of seasonal and regional dynamics, with large temporal heterogeneity in the insect tissue colonization rate and detection of M. ulcerans only in water bug tissues collected in Buruli ulcer endemic areas. Conclusion/Significance The large-scale detection of bacilli in saliva of biting water bugs gives enhanced weight to their role in M. ulcerans transmission. On practical grounds, beyond the ecological interest, the results concerning seasonal and regional dynamics can provide an efficient tool in the hands of sanitary authorities to monitor environmental risks associated with Buruli ulcer., Author Summary Buruli ulcer, caused by Mycobacterium ulcerans, is a devastating skin disease. Most cases of Buruli ulcer occur in poor rural communities. As a result, treatment is frequently sought too late and about 25% of those infected—particularly children—become permanently disabled. Outbreaks of Buruli ulcer have always been associated with swampy areas. However, the route(s) of bacillus transmission is (are) still unclear. This Mycobacterium species resides in water where it colonizes many ecological niches such as aquatic plants, herbivorous animals and predatory/carnivorous insects. For several years the role of water bugs as hosts and vectors of M. ulcerans was suspected and was demonstrated under laboratory conditions. The aim of this work was to further assess the role of water bugs as hosts and vectors of M. ulcerans in environmental context. This work identifies several water bug families as hosts of M. ulcerans in Buruli ulcer endemic area. The detection of bacilli in saliva of human biting insects provides further evidence for their role in M. ulcerans transmission. Interestingly, three of these insects are good flyers, and as such could participate in M. ulcerans dissemination.

Single-domain antibodies specific to methotrexate (MTX) were obtained after immunization of one llama (Llama glama). Specific VHH domains (V-D-J-REGION) were selected by panning from an immune-llama library using phage display technology. The antibody fragments specific to MTX were purified from Escherichia coli (C41 strain) periplasm by immobilized metal affinity chromatography with an expression level of around 10mg/L. A single band around 16,000Da corresponding to VHH fragments was found after analysis by SDS-PAGE and Western blotting, while competition ELISA demonstrated selective binding to soluble MTX. Surface plasmon resonance (SPR) analysis showed that anti-MTX VHH domains had affinities in the nanomolar range (29-515nM) to MTX-serum albumin conjugates. The genes encoding anti-MTX VHH were found by IMGT/V-QUEST to be similar to the previously reported llama and human IGHV germline genes. The V-D and D-J junction rearrangements in the seven anti-MTX CDR3 sequences indicate that they were originated from three distinct progenitor B cells. Our results demonstrate that camelid single-domain antibodies are capable of high affinity binding to low molecular weight hydrosoluble haptens. Furthermore, these anti-MTX VHH give new insights on how the antigen binding repertoire of llama single-domain antibody can provide combining sites to haptens in the absence of a VL. This type of single-domain antibodies offers advantages compared to murine recombinant antibodies in terms of production rate and sequence similarity to the human IGHV3 subgroup genes.

International audience; BACKGROUND: Buruli ulcer is a severe human skin disease caused by Mycobacterium ulcerans. This disease is primarily diagnosed in West Africa with increasing incidence. Antimycobacterial drug therapy is relatively effective during the preulcerative stage of the disease, but surgical excision of lesions with skin grafting is often the ultimate treatment. The mode of transmission of this Mycobacterium species remains a matter of debate, and relevant interventions to prevent this disease lack (i) the proper understanding of the M. ulcerans life history traits in its natural aquatic ecosystem and (ii) immune signatures that could be correlates of protection. We previously set up a laboratory ecosystem with predatory aquatic insects of the family Naucoridae and laboratory mice and showed that (i) M. ulcerans-carrying aquatic insects can transmit the mycobacterium through bites and (ii) that their salivary glands are the only tissues hosting replicative M. ulcerans. Further investigation in natural settings revealed that 5%-10% of these aquatic insects captured in endemic areas have M. ulcerans-loaded salivary glands. In search of novel epidemiological features we noticed that individuals working close to aquatic environments inhabited by insect predators were less prone to developing Buruli ulcers than their relatives. Thus we set out to investigate whether those individuals might display any immune signatures of exposure to M. ulcerans-free insect predator bites, and whether those could correlate with protection. METHODS AND FINDINGS: We took a two-pronged approach in this study, first investigating whether the insect bites are protective in a mouse model, and subsequently looking for possibly protective immune signatures in humans. We found that, in contrast to control BALB/c mice, BALB/c mice exposed to Naucoris aquatic insect bites or sensitized to Naucoris salivary gland homogenates (SGHs) displayed no lesion at the site of inoculation of M. ulcerans coated with Naucoris SGH components. Then using human serum samples collected in a Buruli ulcer-endemic area (in the Republic of Benin, West Africa), we assayed sera collected from either ulcer-free individuals or patients with Buruli ulcers for the titre of IgGs that bind to insect predator SGH, focusing on those molecules otherwise shown to be retained by M. ulcerans colonies. IgG titres were lower in the Buruli ulcer patient group than in the ulcer-free group. CONCLUSIONS: These data will help structure future investigations in Buruli ulcer-endemic areas, providing a rationale for research into human immune signatures of exposure to predatory aquatic insects, with special attention to those insect saliva molecules that bind to M. ulcerans.

During October 2003, we completed an exploratory mission to some locations in the Ouémé Valley to collect insects. A total of nine species and some specimens apparently belonging to the Elmidae and Odonata were collected during the mission. ‘Dejoux et al., 1981' confirmed that the rare or poorly known species are sparcely distributed, and it is unlikely that they would be encountered within a small area. Keywords: insects aquatic, Ouémé Valley, Benin Tropical Freshwater Biology Vol. 14 2005: 1-7

Mycobacterium ulcerans was first identified as the causative agent of Buruli ulcer; this cutaneous tissue-destructive process represents the third most important mycobacterial disease in humans after tuberculosis and leprosy. More recently other life traits were documented. M. ulcerans is mainly detected in humid tropical zones as part of a complex ecosystem comprising algae, aquatic insect predators of the genus Naucoris, and very likely their vegetarian preys. Coelomic plasmatocytes could be the first cells of Naucoris cimicoides to be involved in the infection process, acting as shuttle cells that deliver M. ulcerans to the salivary glands as suggested by both in vitro and in vivo approaches. Furthermore, a key element for the early and long-term establishment of M. ulcerans in Naucoridae is demonstrated by the fact that only mycolactone toxin-producing M. ulcerans isolates are able to invade the salivary glands, a site where they proliferate. Later, the raptorial legs of Naucoris are covered by M. ulcerans-containing material that displays features of biofilms.

Accumulative indirect evidence of the epidemiology of Mycobacterium ulcerans infections causing chronic skin ulcers (i.e., Buruli ulcer disease) suggests that the development of this pathogen and its transmission to humans are related predominantly to aquatic environments. We report that snails could transitorily harbor M. ulcerans without offering favorable conditions for its growth and replication. A novel intermediate link in the transmission chain of M. ulcerans becomes likely with predator aquatic insects in addition to phytophage insects. Water bugs, such as Naucoris cimicoides , a potential vector of M. ulcerans, were shown to be infected specifically by this bacterium after feeding on snails experimentally exposed to M. ulcerans .

Mycobacterium ulcerans is an emerging environmental pathogen which causes chronic skin ulcers (i.e., Buruli ulcer) in otherwise healthy humans living in tropical countries, particularly those in Africa. In spite of epidemiological and PCR data linking M. ulcerans to water, the mode of transmission of this organism remains elusive. To determine the role of aquatic insects in the transmission of M. ulcerans , we have set up an experimental model with aquariums that mimic aquatic microenvironments. We report that M. ulcerans may be transmitted to laboratory mice by the bite of aquatic bugs (Naucoridae) that are infected with this organism. In addition, M. ulcerans appears to be localized exclusively within salivary glands of these insects, where it can both survive and multiply without causing any observable damage in the insect tissues. Subsequently, we isolated M. ulcerans from wild aquatic insects collected from a zone in the Daloa region of Ivory Coast where Buruli ulcer is endemic. Taken together, these results point to aquatic insects as a possible vector of M. ulcerans .

Anti-disialoganglioside (GD2) monoclonal antibodies (MAbs) have been used in vivo for immunolocalization and in phase I and II trials to target disseminated neuroblastoma, the most common extracranial solid tumor in children. However, the efficacy of these first-generation MAbs is likely to be improved by using engineered anti-GD2 antibodies. The generation of single-chain antibody fragments (scFv) could be very helpful as these molecules can be further modified to produce recombinant molecules with pre-defined properties such as immunotoxins, chimeric, or bispecific antibodies. Thus, a scFv directed against GD2 (scFv 7A4) was cloned, sequenced, and expressed. Its binding properties were characterized and compared to that of the parental MAb 7A4. Nucleotide sequence analysis of the scFv 7A4 indicated that its VH region belongs to the V region IIID subgroup and the V kappa to the V region II subgroup. The scFv 7A4 bound to GD2+ neuroblastoma cell lines but not to GD2- cell lines or to GD2- cells isolated from peripheral blood. ELISA and thin-layer chromatography (TLC) indicated that it retained the anti-GD2 specificity, and exhibited a slight cross-reaction with GD3 as the parental MAb. This scFv makes it possible to develop new useful reagents through genetic engineering for adjuvant tumor therapy.

International audience; Current antiangiogenic immunotherapeutic strategies mainly focus on the blockade of circulating cytokines or receptors that are overexpressed by endothelial cells. We proposed globotriaosylceramide (Gb3) as a viable alternative target for antiangiogenic therapies. In this setting, we developed an anti-Gb3 antibody and validated its therapeutic efficacy in metastatic tumor models. © 2013 Landes Bioscience.

Various ligands have been involved in the process of infection and tissue invasion of C. albicans 1. It is adherence is enhanced when germ-tubes are emerging from blastospores. The importance of yeast germination raises the possibility of a molecular organization of cell walls different between blastospores and hyphae. Major biochemical differences have been described,but the functional significance of the molecules specific to germ-tubes remains to be determined. Further features should be given by the hybridoma technology to identify surface antigens. Paradoxically a limited number of informative monoclonal antibodies was obtained by immunization of mice with whole organisms. Generally mannoproteins of yeasts cell wall were recognized 2,5. A different approach was attempted from fibrinogen binding factors released by the germ-tubes of C. albicans that we had reported previously 1. We describe the reactivity and characteristics of a murine monoclonal antibody 3D9 directed to a component of germ-tube of C. albicans.

Two fractions were separated from the proteins of the mineral compartment of bovine developing enamel on the basis of their affinity for the lectin concanavalin-A. A monoclonal antibody was prepared by the hybridoma technique against the Con-A-binding fraction. This antibody and a commercial polyclonal antibody against bovine serum albumin were used to examine the relationship between those proteins, serum albumin and alpha-2HS glycoprotein, two proteins concentrated within dentin and bone matrices. The Con-A-unbound fraction reacted with the anti-albumin antibody and the antibody against the Con-A-binding fraction recognized the alpha-2HS glycoprotein. These data fully support the presence of significant levels of proteins related to serum components in the mineral compartment of developing enamel matrix.

The role of biofilms in the pathogenesis of mycobacterial diseases remains largely unknown. Mycobacterium ulcerans, the etiological agent of Buruli ulcer, a disfiguring disease in humans, adopts a biofilm-like structure in vitro and in vivo, displaying an abundant extracellular matrix (ECM) that harbors vesicles. The composition and structure of the ECM differs from that of the classical matrix found in other bacterial biofilms. More than 80 proteins are present within this extracellular compartment and appear to be involved in stress responses, respiration, and intermediary metabolism. In addition to a large amount of carbohydrates and lipids, ECM is the reservoir of the polyketide toxin mycolactone, the sole virulence factor of M. ulcerans identified to date, and purified vesicles extracted from ECM are highly cytotoxic. ECM confers to the mycobacterium increased resistance to antimicrobial agents, and enhances colonization of insect vectors and mammalian hosts. The results of this study support a model whereby biofilm changes confer selective advantages to M. ulcerans in colonizing various ecological niches successfully, with repercussions for Buruli ulcer pathogenesis., Author Summary Mycobacterium ulcerans is the etiologic agent of Buruli ulcer, a necrotic skin disease affecting humans living close to wetlands in tropical countries. This mycobacteria resides in water where it could colonize many ecological niches such as aquatic plants, herbivorous animals, and water bugs. The latter were shown to be able to transmit the bacteria to mammalian hosts. Here, we described that the bacilli could be structured with a thick envelope called the extracellular matrix (ECM). This peculiar coat contains in small vesicles a toxin named mycolactone, the main virulence factor of M. ulcerans. The ECM confers to the mycobacterium increased resistance to antimicrobial agents and plays a role in virulence. Indeed, a bacteria with ECM is more potent for colonization of insect vectors and mammalian hosts compared to bacteria. Unraveling the regulation of the production of the ECM together with the export of mycolactone will be an important step in developing new pharmacological approaches for the treatment of Buruli ulcer, which has been greatly handicapped by the lack of effectiveness of the current antibiotics.

These compounds are obtained through solid-state reaction between the elements in sealed tubes. They remain unaltered with atmospheric moisture. X-ray diffraction gives evidence for pseudocubic symmetry. The atomic stacking is considered to be of disordered sphalerite type. BeAs2 and BeSb2 behave as semiconductors.

Resume L'etude est limitee au domaine 0 Bi Ba . La pression d'oxygene est au maximum de 200 bars. Le diagramme de phases est etabli par l'analyse chimique et les rayons X. Une phase perovskite est mise en evidence de composition (Ba1−yBiy)A (Fe1−yBiy)BO3−x. L'evolution des proprietes electriques et magnetiques est surtout influencee par le degre d'oxydation moyen des composes obtenus. La constante dielectrique est elevee mais avec un angle de perte important.

CaAs 3 is prepared through reaction of gaseous arsenic with calcium metal at 800–900°C in a sealed silica tube. X-ray powder diffraction is indexed by analogy with CaP 3 . The triclinic cell of CaAs 3 is refined by applying the least-squares method: a =5.854(5) ; b =5.832(5) ; c =5.901(5) ; α =70.2(1) o , β =80.3(1) o , γ =75.7(1) o . The compound is isotypic with CaP 3 (space group P ī). Its structure is refined with X-ray powder intensities. The CaAs 3 structure can be interpreted as formed of layers of arsenic, between which we can find the calcium atoms. The chains of As atoms are reminiscent of those existing in the orthorhombic As structure.

In the course of a study of the ZnOFe0.89OFe3O4 system at 900°C, evidence has been obtained for a new phase which can be formulated ZnxFe0.085−xO (0.085 ≤ x ≤ 0.170). The cell is cubic with a parameter a = 12.836 A; the space group determined through electron microdiffraction and X-ray diffraction is Pn3 or Pn3m. This phase is antiferromagnetic with TN varying between 52 and 85°C; it is an n-type semiconductor.

A number of studies have suggested that some biological membrane functions might be correlated with the physical state of the phospholipids in these membranes [l-4] . Breaks in the Arrhenius plots of enzymatic or transport activities have indicated a possible relationship between phase transitions in the phospholipids [l-3] and these activities. Recently it has been shown by ‘H NMR and X-ray diffraction that in sarcopIasmic reticulum membranes no order + disorder type of transitions occur in the temperature range l-40°C, but breaks in the Arrhenius plots for the rates of Ca2+ transport and Ca” activated ATPase were observed between 15°C and 25°C [4] . This observation indicates a possible association between the character of the phospholipid segmental motion and the functional parameters of the membranes. Binding of Con A on right side-out (RSO) plasma membrane vesicles was shown to affect the activities of 5’nucleotidase (EC 3.1.3.5) and of (Na’ t K+) stimulated Mg2’-ATPase (EC 3.6.1.3), while it had no effect on the inside-out (IO) vesicles of the same plasma membranes. In contrast, a peptidoglycan-like adjuvant was effective in modulating the enzymes, only on the IO vesicles [5] . It is the purpose of this letter to show that binding of these ligands on the reactive membrane face affect the membrane phospholipid fluidity.

Resume Pres de 90 p. cent de l'activite totale de la guanylate cyclase de cellules d'un plasmocytome murin est retrouvee dans la fraction membranaire plasmique. Son activite specifique augmente de six fois en presence de Triton X-100. Le rapport d'activite enzymatique entre vesicules membranaires plasmiques a polarite inverse (10) et a polarite normale (RSO) est de neuf fois. Cette difference disparait par traitement de ces vesicules avec le Triton X-100, montrant par la meme que le site catalytique de la guanylate cyclase est situe sur la face interne de la membrane plasmique. L'activite de la guanylate cyclase est optimum en presence de manganese. Seulement 20 p. cent de cette activite est retrouvee avec le magnesium. Le Km de l'enzyme pour le GTP est environ sept fois plus eleve avec le magnesium (1.4 mM) qu'avec le manganese (0.2 mM). Dans les deux cas, il existe un phenomene de cooperativite positive : les coefficients de Hill sont de 1.8 pour le manganese et de 1.6 pour le magnesium. L'ATP aux concentrations physiologiques pourrait jouer un role regulateur sur cette activite enzymatique qu'il inhibe en presence de manganese et de magnesium.

By studying the CaH2CaF2 system at 700°C, we associate F− and H− anions in the same ternary combination. The existence of solid solutions of composition CaF2−xHx (0 < x ⩽ 1.24) is established, crystallizing in CaF2-type cubic symmetry. The solid solution parameter is considered constant as the composition varies, since there is a variation of 1100 A between pure CaF2 (a = 5.463 A) and the limit phase CaF0.76H1.24 (a = 5.452(5) A). Thus the two anions H− and F− are approximately the same size in the mixed hydride fluorides of calcium. X-ray and neutron diffraction studies indicate a structure in which there is a statistical substitution of fluoride ions by hydride ions on the 8c sites of the CaF2 unit cell.

The Li2O-NiO-O2 system is described at 670° C in the oxygen pressure range 1.3×10−8 to 150 bars (and the phase diagram is extended up to Li2NiO3). The consequences of oxygen stoichiometry are emphasized in relation to the magnetic properties.

The treatment of plasma membranes by a French pressure cell in sucrose medium devoid of detergents solubilized 20% of the total protein and 95--100% of 5'-nucleotidase activity. The soluble enzyme was 40--90-fold purified by centrifugation in a sucrose gradient with a 10--20% yield with respect to the orginal lysate. The purified fraction retained the same high specificity for 5'-AMP (Km = 20 micron) as in the plasma membranes and was enriched in sphingomyelin. Whereas 5'-AMP at high concentration inhibited the membrane-bound enzyme, it had no effect on the solubilized form. The soluble enzyme was stimulated by 2 X 10(-13)-2 X 10(-15) g concanavalin A without any inhibition with higher doses of lectin. The plasma-membrane bound stimulated and inhibited 5'-nucleotidase was modulated by concanavalin A concentrations higher than 0.1 microgram. Inhibition of the activity of the soluble enzyme by antiphosphorylcholine antibodies was not observed with membranes. The regulation of 5'-nucleotidase acitvity in plasma membranes might be associated with a supramolecular organization.

The phosphidation of beryllium in the presence of traces of hydrogen leads to non stoichiometric ternary phases BeP2−xHy. The stoichiometric diphosphide BeP2 cannot be obtained. The hydrogenated phases are black and non hygroscopic. The structural study with X rays diffraction, neutrons diffraction, electronic microdiffraction, as well as the crystallographic data from single crystal, provide evidence for a quadratic cell with a = 7,08 A & c = 30,12 A . The stacking is diamond type when considering all the atoms : Be, P and H.

Purified right-side-out (RSO) and inside-out (IO) plasma membrane vesicles release 35% of the total plasma membrane proteins after EDTA treatment. After such a treatment both types of vesicles exhibited the same total activity of (Na+ + K+)-stimulated Mg2+ adenosinetriphosphatase (ATPase; ATP phosphohydrolase, EC 3.6.1.3) as in their native state. The EDTA treatment increases the enzyme sensitivity to ouabain by 350-fold in IO vesicles while being without any effect RSO vesicles. Thus, proteins released only from the IO vesicles led to a change in ouabain sensitivity of the (Na+ + K+)-stimulated Mg2+ ATPase. Moreover, only proteins released from IO vesicles, when added to treated IO vesicles with divalent cations, were able to restore the original resistance of the enzyme to ouabain; released proteins from RSO vesicles failed to make such a reconstitution. Thus, we assume that these proteins detach from the inner face of the plasma membrane upon EDTA treatment and are distinct from the enzyme. Polyacrylamide gel electrophoresis indicates that these inner face plasma membrane proteins are approximately 30,000 daltons.