Antibodies against the Plasmodium falciparum glutamate-rich protein from naturally exposed individuals living in a Brazilian malaria-endemic area can inhibit in vitro parasite growth

The glutamate-rich protein (GLURP) is an exoantigen expressed in all stages of the Plasmodium falciparum life cycle in humans. Anti-GLURP antibodies can inhibit parasite growth in the presence of monocytes via antibody-dependent cellular inhibition (ADCI), and a major parasite-inhibitory region has been found in the N-terminal R0 region of the protein. Herein, we describe the antiplasmodial activity of anti-GLURP antibodies present in the sera from individuals naturally exposed to malaria in a Brazilian malaria-endemic area. The anti-R0 antibodies showed a potent inhibitory effect on the growth of P. falciparum in vitro, both in the presence (ADCI) and absence (GI) of monocytes. The inhibitory effect on parasite growth was comparable to the effect of IgGs purified from pooled sera from hyperimmune African individuals. Interestingly, in the ADCI test, higher levels of tumour necrosis factor alpha (TNF-α) were observed in the supernatant from cultures with higher parasitemias. Our data suggest that the antibody response induced by GLURP-R0 in naturally exposed individuals may have an important role in controlling parasitemia because these antibodies are able to inhibit the in vitro growth of P. falciparum with or without the cooperation from monocytes. Our results also indicate that TNF-α may not be relevant for the inhibitory effect on P. falciparum in vitro growth.

Prevalence of hepatitis E virus antibodies in individuals exposed to swine in Mato Grosso, Brazil

This study was conducted to estimate the prevalence of hepatitis E antibodies (anti-HEV) among individuals exposed to swine in the rural areas of the state of Mato Grosso (MT) in Brazil. The study included 310 participants who had an average age of 39 years. Fifty-one per cent of the participants were female and 26 (8.4%) were anti-HEV-positive. Concomitantly, we studied 101 blood donors from the urban area of the state capital who had never lived in a rural area or handled swine. Four per cent (4%) of these individuals were anti-HEV-positive (p = 0.206). When we compared the anti-HEV-positive participants who had been exposed to swine with the anti-HEV-negative participants, we noticed associations between the presence of anti-HEV and increased age, a history of blood transfusions and contact with other farm animals. However, after a multivariate analysis was performed, this association was not confirmed. Finally, the ratio of anti-HEV-positive individuals who had been exposed to swine in rural MT was similar to that found in previous studies in Brazil. This prevalence did not characterise this type of exposure as a risk factor for HEV infection in this region.

Distributed fire detector system

Aquest treball pretén elaborar un sistema de detecció d'incendis implementat sota una xarxa de sensors sense fils. Aquesta xarxa està formada per petits dispositius autònoms equipats amb un transmissor de ràdio, un microcontrolador, diferents sensors (temperatura, lluminositat i efecte Hall) i alimentació per bateries (AA).

Anaphylaxis caused by imported red fire ant stings in Málaga, Spain.

A 27-year-old woman suffered from anaphylaxis after being stung by Solenopsis invicta ants while she was handling wood from South America. The patient reported no previous adverse reactions to stings by other hymenopteran species. Intradermal skin tests with hymenoptera venom (Vespula vulgaris, Polistes species, Apis melifera) were negative. Serum specific immunoglobulin (Ig) E yielded positive results for S invicta (5.28 kU/L) and negative results for A melifera, Ves v 5 and Pol a 5. Immunodetection assays showed the presence of serum IgE against the Sol i 2 allergen. The patient had probably been stung previously although inadvertently by red fire ants while she handled infested wood from South America, and precautionary measures are thus advisable when this material is to be handled. To our knowledge this is the first case of anaphylaxis from red fire ant stings reported in Europe.

Effects of ploidy and sex-locus genotype on gene expression patterns in the fire ant Solenopsis invicta.

Males in many animal species differ greatly from females in morphology, physiology and behaviour. Ants, bees and wasps have a haplodiploid mechanism of sex determination whereby unfertilized eggs become males while fertilized eggs become females. However, many species also have a low frequency of diploid males, which are thought to develop from diploid eggs when individuals are homozygous at one or more sex determination loci. Diploid males are morphologically similar to haploids, though often larger and typically sterile. To determine how ploidy level and sex-locus genotype affect gene expression during development, we compared expression patterns between diploid males, haploid males and females (queens) at three developmental timepoints in Solenopsis invicta. In pupae, gene expression profiles of diploid males were very different from those of haploid males but nearly identical to those of queens. An unexpected shift in expression patterns emerged soon after adult eclosion, with diploid male patterns diverging from those of queens to resemble those of haploid males, a pattern retained in older adults. The finding that ploidy level effects on early gene expression override sex effects (including genes implicated in sperm production and pheromone production/perception) may explain diploid male sterility and lack of worker discrimination against them during development.

Social and immunological differences among uninfected Brazilians exposed or unexposed to human immunodeficiency virus-infected partners

Understanding the social conditions and immunological characteristics that allow some human immunodeficiency virus (HIV)-exposed patients to remain uninfected represents an on-going challenge. In this study, the socio-demographic and sexual behaviour characteristics and immune activation profiles of uninfected individuals exposed to HIV-infected partners were investigated. A confidential and detailed questionnaire was administered and venous blood was tested using HIV-1/enzyme immunoassays, plasma HIV-1 RNA levels/bDNA and immunophenotyping/flow cytometry to determine the frequencies of CD4 and CD8 T cells expressing activation markers. The data analysis showed significant differences (p < 0.05) for immune parameters in individuals who were uninfected, albeit exposed to HIV-infected partners, compared with unexposed individuals. In particular, the exposed, uninfected individuals had a higher frequency (median, minimum-maximum) of CD4+HLA-DR+ (4.2, 1.8-6.1), CD8+HLA-DR+ (4.6, 0.9-13.7), CD4+CD45RO+ (27.5, 14.2-46.6), CD4+CD45RO+CD62L+ (46.7, 33.9-67.1), CD8+CD45RA+HLA-DR+ (12.1, 3.4-35.8) and CD8+CD45RO+HLA-DR+ (9.0, 3.2-14.8) cells, a decreased percentage of CD8+CD28+ cells (11.7, 4.5-24.0) and a lower cell-surface expression of Fcγ-R/CD16 on monocytes (56.5, 22.0-130.0). The plasma HIV-1 RNA levels demonstrated detectable RNA virus loads in 57% of the HIV-1+ female partners. These findings demonstrate an activation profile in both CD4 and CD8 peripheral T cells from HIV-1 exposed seronegative individuals of serodiscordant couples from a referral centre in Belo Horizonte, state of Minas Gerais.

Clara cell protein and surfactant protein B in garbage collectors and in wastewater workers exposed to bioaerosols

OBJECTIVES: Inhalation of bioaerosols has been hypothesised to cause "toxic pneumonitis" that should increase lung epithelial permeability at the bronchioloalveolar level. Serum Clara cell protein (CC16) and serum surfactant protein B (SPB) have been proposed as sensitive markers of lung epithelial injury. This study was aimed at looking for increased lung epithelial permeability by determining CC16 and SPB in workers exposed to bioaerosols from wastewater or garbage. METHODS: Subjects (778 wastewater, garbage and control workers; participation 61%) underwent a medical examination, lung function tests [American Thoracic Society (ATS) criteria], and determination of CC16 and SPB. Symptoms of endotoxin exposure and several potential confounders (age, gender, smoking, kidney function, obesity) were looked for. Results were examined with multiple linear or logistic regression. RESULTS: Exposure to bioaerosols increased CC16 concentration in the wastewater workers. No effect of exposure on SPB was found. No clue to work-related respiratory diseases was found. CONCLUSIONS: The increase in CC16 in serum supports the hypothesis that bioaerosols cause subclinical "toxic pneumonitis", even at low exposure. [Authors]

Development of a retrospective job exposure matrix for PCB-exposed workers in capacitor manufacturing

Objectives: Polychlorinated biphenyls (PCBs) are considered probable human carcinogens by the International Agency for Research on Cancer and one congener, PCB126, has been rated as a known human carcinogen. A period-specific job exposure matrix (JEM) was developed for former PCB-exposed capacitor manufacturing workers (n=12,605) (1938-1977). Methods: A detailed exposure assessment for this plant was based on a number of exposure determinants (proximity, degree of contact with PCBs, temperature, ventilation, process control, job mobility). The intensity and frequency of PCB exposures by job for both inhalation and dermal exposures, and additional chemical exposures were reviewed. The JEM was developed in nine steps: (1) all unique jobs (n=1,684) were assessed using (2) defined PCB exposure determinants; (3) the exposure determinants were used to develop exposure profiles; (4) similar exposure profiles were combined into categories having similar PCB exposures; (5) qualitative intensity (high-medium-low-baseline) and frequency (continuous-intermittent) ratings were developed, and (6) used to qualitatively rate inhalation and dermal exposure separately for each category; (7) quantitative intensity ratings based on available air concentrations were developed for inhalation and dermal exposures based on equal importance of both routes of exposure; (8) adjustments were made for overall exposure, and (9) for each category the product of intensity and frequency was calculated, and exposure in the earlier era was weighted. Results: A period-specific JEM modified for two eras of stable PCB exposure conditions. Conclusions: These exposure estimates, derived from a systematic and rigorous use of the exposure determinant data, lead to cumulative PCB exposure-response relationships in the epidemiological cancer mortality and incidence studies of this cohort. [Authors]

Levels of PSP toxins in bivalves exposed to natural blooms of Alexandrium minutum in Catalan harbours

The development, validation, comparison and evaluation of analytical methods for marine toxins rely on the availability of toxic material. Within the project JACUMAR PSP, our interest is mainly focused on autochthonous bivalve species with the toxic profile of Alexandrium minutum, since this is the principal species involved regionally in PSP outbreaks. Mussels and oysters were exposed during few days in the harbor of Vilanova i la Geltrú, to blooms reaching a maximum A. minutum concentration of 200,000 cells L-1 in 2008, and 40,000 and 800,000 cells L-1, in 2009. Mussels, oysters and clams were exposed to one bloom of 22,000 cells L-1 in the harbor of Cambrils in 2009. In all situations higher toxic levels analyzed by HPLC-FD with postcolumn oxidation were observed in mussels (i.e. 1,200-2,500 μg eq. STX kg-1) than in oysters (i.e. 60-800 μg eq. STX kg-1) exposed to the same bloom. Blooms with higher concentrations of A. minutum did not correspond to higher levels of PSP toxins in bivalves. These differences may be explained by differences in A. minutum population dynamics, toxin production or in the physiological state or behaviour of shellfish. These results confirm that mussels concentrate more PSP toxins from A. minutum than oysters and clams.

Hyperbolic reaction-diffusion equations for a forest fire model

Forest fire models have been widely studied from the context of self-organized criticality and from the ecological properties of the forest and combustion. On the other hand, reaction-diffusion equations have interesting applications in biology and physics. We propose here a model for fire propagation in a forest by using hyperbolic reaction-diffusion equations. The dynamical and thermodynamical aspects of the model are analyzed in detail

Oxytocin response to an experimental psychosocial challenge in adults exposed to traumatic experiences during childhood or adolescence.

Long-term implications of the exposure to traumatizing experiences during childhood or adolescence, such as sexual abuse, or cancer, have been documented, namely the subjects' response to an acute stress in adulthood. Several indicators of the stress response have been considered (e.g. cortisol, heart rate). Oxytocin (OT) response to an acute stress of individuals exposed to trauma has not been documented. Eighty subjects (n=26 women who had experienced episodes of child abuse, n=25 men and women healthy survivors of cancer in childhood or adolescence, and 29 controls) have been submitted to a laboratory session involving an experimental stress challenge, the Trier social stress test. Overall, there was a clear OT response to the psychosocial challenge. Subjects having experienced a childhood/adolescence life-threatening illness had higher mean levels of OT than both abused and control subjects. There was a moderate negative relationship between OT and salivary cortisol. It is suggested that an acute stress stimulates OT secretion, and that the exposure to enduring life-threatening experiences in childhood/adolescence has long-lasting consequences regarding the stress system and connected functions, namely the activation of OT secretion. Better knowledge of such long-term implications is important so that to prevent dysregulations of the stress responses, which have been shown to be associated to the individual's mental health.

Single loci with major effects in fire ants : the effects of the complementary sex-determining locus and the green beard supergene on gene expression

Etant données la complexité et la redondance des réseaux de gènes influençant de nombreux phénotypes, l'étude des rares cas d'un locus unique ayant des effets importants sur de nombreux phénotypes peut fournir des informations cruciales sur l'évolution des traits complexes. Nous avons séquencé le génome de la fourmi de feu Solenopsis invicta pour étudier comment l'expression des gènes détermine les effets majeurs et étendus de deux loci uniques sur le phénotype. Le premier locus concerne la détermination du sexe par le modèle des allèles complémentaires. Ce locus est connu pour déterminer le sexe chez tous les hyménoptères mais n'a été caractérisé que chez les abeilles. Les hétérozygotes pour ce locus se développent en reines diploïdes (ou ouvrières stériles) alors que les homozygotes se développent en mâles diploïdes incapables de produire du sperme et les hémizygotes en mâles haploïdes fertiles. Nous avons comparé l'expression des gènes entre les reines et les deux types de mâles au stade pupe, ainsi que 1 et 11 jours après l'émergence. Nous avons trouvé un changement prononcé de l'expression des gènes chez les mâles diploïdes, passant de très proche de celle des reines au stade pupe à identique aux mâles haploïdes 11 jours après l'émergence. Cela signifie que les mâles diploïdes sont condamnés à être stériles parce que les effets après émergence du locus de détermination du sexe ne per¬mettent pas d'effacer les effets de la ploïdie sur l'expression des gènes pendant le stade pupe, quand la spermatogénèse prend place. Le second locus aux effets majeurs que nous avons étudié est le supergène dit "green beard", qui consiste en 616 gènes couvrant 55% d'un chromosome (13 Mb) et est caractérisé par une absence de recombinaison entre les deux variants du supergène : "Social B" et "Social b" (SB et Sb). Au travers de l'effet "green beard", par lequel les ouvrières avec le supergène Sb discriminent favorablement les reines qui partagent ce supergène de façon perceptible, le génotype des reines fondatrices au niveau de ce supergène détermine l'organisation de la colonie : soit elle contient une seule reine SB/SB, soit plusieurs reines SB/Sb. Nous avons montré que le chromosome Sb a évolué comme le chromosome Y, accumulant probablement des allèles favorables dans des colonies avec plusieurs reines mais défavorables dans des colonies avec une seule reine (cf. gènes sexuellement antagonistes), ainsi que des transposons et des séquences répéti¬tives. Nous avons également montré que le polymorphisme du supergène cause de grandes différences d'expression chez les ouvrières et particulièrement les reines mais pas chez les mâles. Pour comprendre comment le polymorphisme du supergène chez les reines peut affecter l'organisation de la colonie, nous avons comparé l'expression entre les génotypes SB/SB et SB/Sb chez des reines vierges (1 et 11 jours) et des reines matures. Nous avons montré que les reines SB/SB sur-régulent des gènes impliqués dans la reproduction, expli-quant pourquoi elle grandissent plus rapidement et peuvent fonder des colonies de façon indépendante, tandis que les reines SB/Sb (qui ne peuvent fonder une nouvelle colonie) sur-régulent des gènes de signalement chimique qui affectent l'organisation des colonies par l'effet "green beard". - Given the complexity and redundancy of the gene networks that underlie many pheno- types, the study of rare cases of a single locus having major effects on many phenotypes can give powerful insights into the evolution of complex traits. We sequenced the genome of Solenopsis invicta fire ants to study how gene expression mediates the widespread major effects of two single loci on phenotype. The first is the complementary sex-determining locus, which is known to exist in most Hymenoptera despite being characterized only for honeybees. Heterozygotes at this locus become diploid queens (or sterile workers), homozy¬gotes become aspermic diploid males, and hemizygotes become fertile haploid males. We compared gene expression between queens and both types of males in pupae and 1 and 11 days after eclosion. We found a pronounced shift in gene expression in diploid males, from being nearly identical to queens as pupae to identical to haploid males 11 days after eclosion. This means that diploid males are condemned to sterility because the overriding effects of the sex locus after eclosion cannot undo the ploidy effects on expression during the pupal stage, when spermatogenesis must be completed. The second locus with major ef¬fects that we studied was the so-called "green beard" supergene, which consists of 616 genes encompassing 55% of one chromosome (13 Mb), without recombination between the two variants "Social B" and "Social b" (SB and Sb) supergene. Through the green beard effect, i.e. workers with the Sb supergene discriminating in favor of queens who perceptibly share this supergene, the founding queen's genotype at the supergene determines colony organi¬zation: either headed by a single SB/SB queen or many SB/Sb queens. We show that the Sb chromosome evolved like a Y-chromosome, probably accumulating alleles beneficial in multi-queen colonies but disadvantageous in single-queen colonies (cf. sexually antagonistic genes), as well as transposons and repetitive sequences. We also show that the polymor¬phism of the supergene causes widespread expression differences in workers and especially queens but not in males. To understand how the polymorphism at the supergene in queen can transform colony organization, we compared the expression between SB/SB and SB/Sb virgin queens (1 and 11 days) and mother queens. We show that SB/SB queens up-regulate genes involved in reproduction, explaining why they mature faster and can found colonies independently, while SB/Sb queens (which cannot found colonies) up-regulate chemical signaling genes that can transform colonies through the green beard effect.

Mechanisms of antagonism of Pseudomonas fluorescens EPS62e against Erwinia amylovora, the causal agent of fire blight

Pseudomonas fluorescens EPS62e was selected during a screening procedure for its high efficacy in controlling infections by Erwinia amylovora, the causal agent of fire blight disease, on different plant materials. In field trials carried out in pear trees during bloom, EPS62e colonized flowers until the carrying capacity, providing a moderate efficacy of fire-blight control. The putative mechanisms of EPS62e antagonism against E. amylovora were studied. EPS62e did not produce antimicrobial compounds described in P. fluorescens species and only developed antagonism in King’s B medium, where it produced siderophores. Interaction experiments in culture plate wells including a membrane filter, which physically separated the cultures, confirmed that inhibition of E. amylovora requires cell-to-cell contact. The spectrum of nutrient assimilation indicated that EPS62e used significantly more or different carbon sources than the pathogen. The maximum growth rate and affinity for nutrients in immature fruit extract were higher in EPS62e than in E. amylovora, but the cell yield was similar. The fitness of EPS62e and E. amylovora was studied upon inoculation in immature pear fruit wounds and hypanthia of intact flowers under controlled-environment conditions. When inoculated separately, EPS62e grew faster in flowers, whereas E. amylovora grew faster in fruit wounds because of its rapid spread to adjacent tissues. However, in preventive inoculations of EPS62e, subsequent growth of EPS101 was significantly inhibited. It is concluded that cell-to-cell interference as well as differences in growth potential and the spectrum and efficiency of nutrient use are mechanisms of antagonism of EPS62e against E. amylovora

Westory Fire Agency, June 30, 2003

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