Patterns of digenean parasitism of bivalves from the Great Barrier Reef and associated waters

Digenean parasites of marine bivalves are relatively poorly known, particularly in Australia. We surveyed 2256 bivalve individuals ( 47 species, 17 families) from Queensland marine waters incorporating south-east Queensland, Heron Island ( southern Great Barrier Reef) and Lizard Island ( northern Great Barrier Reef). Infections of trematode species from three families, Bucephalidae, Gorgoderidae and Monorchiidae, were found. Overall prevalence of infection was 2.3%. The Bucephalidae was the most commonly found family; 11 species were found in Tellinidae, Ostreidae, Isognomonidae and Spondylidae - the latter two previously unknown as hosts for bucephalids. A single gorgoderid infection was found in a venerid, Lioconcha castrensis. Five species of monorchiids were found from Tellinidae and Lucinidae. All infections are new host/parasite records. No infections were found in 35 of the 47 bivalve species sampled. The generally low prevalence of infection by digeneans of bivalves suggests that it is unlikely that any of the species reported here are seriously damaging to bivalve populations in these waters. We deduce that, at best, we have some life-cycle information but no actual identifications for 10% of the species of trematodes that infect bivalves of Queensland marine waters.

Molecular characterisation, pathogenesis and fungicide sensitivity of Pythium spp. from table beet (Beta vulgaris var. vulgaris) grown in the Lockyer Valley, Queensland

Table beet production in the Lockyer Valley of south-eastern Queensland is known to be adversely affected by soilborne root disease from infection by Pythium spp. However, little is known regarding the species or genotypes that are the causal agents of both pre- and post-emergence damping off. Based on RFLP analysis with HhaI, HinfI and MboI of the PCR amplified ITS region DNA from soil and diseased plant samples, the majority of 130 Pythium isolates could be grouped into three genotypes, designated LVP A, LVP B and LVP C. These groups comprised 43, 41 and 7% of all isolates, respectively. Deoxyribonucleic acid sequence analysis of the ITS region indicated that LVP A was a strain of Pythium aphanidermatum, with greater than 99% similarity to the corresponding P. aphanidermatum sequences from the publicly accessible databases. The DNA sequences from LVP B and LVP C were most closely related to P. ultimum and P. dissotocum, respectively. Lower frequencies of other distinct isolates with unique RFLP patterns were also obtained with high levels of similarity (> 97%) to P. heterothallicum, P. periplocum and genotypes of P. ultimum other than LVP B. Inoculation trials of 1- and 4-week-old beet seedlings indicated that compared with isolates of the LVP B genotype, a higher frequency of LVP A isolates caused disease. Isolates with the LVP A, LVP B and LVP C genotypes were highly sensitive to the fungicide Ridomil MZ, which suppressed radial growth on V8 agar between approximately four and thirty fold at 5 mu g/mL metalaxyl and 40 mu g/mL mancozeb, a concentration far lower than the recommended field application rate.

Retroviral invasion of the koala genome

Endogenous retroviruses are a common ancestral feature of mammalian genomes with most having been inactivated over time through mutation and deletion(1). A group of more intact endogenous retroviruses are considered to have entered the genomes of some species more recently, through infection by exogenous viruses(2), but this event has never been directly proved. We have previously reported koala retrovirus (KoRV) to be a functional virus that is associated with neoplasia(3). Here we show that KoRV also shows features of a recently inserted endogenous retrovirus that is vertically transmitted. The finding that some isolated koala populations have not yet incorporated KoRV into their genomes, combined with its high level of activity and variability in individual koalas, suggests that KoRV is a virus in transition between an exogenous and endogenous element. This ongoing dynamic interaction with a wild species provides an exciting opportunity to study the process and consequences of retroviral endogenization in action, and is an attractive model for studying the evolutionary event in which a retrovirus invades a mammalian genome.

Safety and use of sputum induction in children with cystic fibrosis

We assessed the safety and use of induced sputum (IS) in children with cystic fibrosis (CF). Forty-eight children (19 males) with CF, mean age 12.6 (range, 7.3-17.0) years and median forced expired volume in 1 sec (FEV1) 48% (range, 14-77%) predicted were recruited. Patients spontaneously expectorated sputum and then performed sputum induction by inhalation of nebulized 7% hypertonic saline. Samples were sent for bacteriological culture, and for measurement of the following inflammatory mediators: interleukin-8, myeloperoxidase, eosinophil cationic protein, and neutrophil elastase activity. FEV1 was performed before and after inhalation of hypertonic saline. There was no increase in mediator levels in IS compared to expectorated sputum (ES) samples. Only 3 patients demonstrated significant bronchoconstriction following inhalation of hypertonic saline, by the method used. From the ES samples, Pseudomonas aeruginosa was isolated in 13 patients, Staphylococcus aureus in 7 patients, Stenotrophomonas maltophilia in 1 patient, and both Pseudomonas aeruginosa and Staphylococcus aureus in 5 patients. All these organisms were found in the IS samples. However, in 2 patients whose ES grew no organisms, one patient's IS grew Pseudomonas aeruginosa, and the other patient's IS grew Staphylococcus aureus. In our study, sputum induction was safe, with no proinflammatory effect.

Examination of the role of Mycoplasma bovis in bovine pneumonia and a mathematical model for its evaluation

The authors screened 34 large cattle herds for the presence of Mycoplasma bovis infection by examining slaughtered cattle for macroscopic lung lesions, by culturing M. bovis from lung lesions and at the same time by testing sera for the presence of antibodies against M. bovis. Among the 595 cattle examined, 33.9% had pneumonic lesions, mycoplasmas were isolated from 59.9% of pneumonic lung samples, and 10.9% of sera from those animals contained antibodies to M.bovis. In 25.2% of the cases M. bovis was isolated from lungs with no macroscopic lesions. The proportion of seropositive herds was 64.7%. The average seropositivity rate of individuals was 11.3% but in certain herds it exceeded 50%. A probability model was developed for examining the relationship among the occurrence of pneumonia, the isolation of M. bovis from the lungs and the presence of M. bovis specific antibodies in sera.

HIV/AIDS: um perfil epidemiológico do vírus e uma análise das práticas seguras, conhecimento e percepção de mulheres

In recent decades, the debate surrounding the consequences of the HIV has passed by great changes. Earlier, prevention campaigns focused risk groups then risk behaviors and ultimately vulnerability. Furthermore, over the years, the dimensions of HIV that emerged in the social environment are these: internalization, heterosexualization, impoverishment and feminization. Based on these contexts, the composition of this study comprises two papers: the former has the overall objective to analyze the epidemiology and incidence of HIV in Brazilian regions in the period from 1980 to 2012; the latter, it aims to find out whether there is the relationship among safe practices, knowledge and perception of women residents in Manaus and Boa Vista cities on the infection by HIV. In paper 1, it was used information from the Health Ministry, as a data source. Besides, it was developed an exploratory and spatial analysis of incidence rates and relative proportion of notified cases. In paper 2, was used as a source of data, the research "Evaluating the process of spatial and epidemic diffusion of HIV in the federal units of Brazil-Northern Region" in 2008. Furthermore, Statistical Techniques of Cluster Analysis, Analysis of Variance, Chi-Square and Logistic Regression were applied. In this paper, it was found that, in Brazilian Regions, the prevalence of reported cases occurred among heterosexuals in men 20-40 year age group and residing in metropolitan areas. It was observed a significant spatial correlation of the incidence rate of reported cases of HIV. It was also noted by the results that have good knowledge and awareness about HIV does not imply, essentially, in a safe sexual intercourse. These results have shown the need public policies geared to the guiding of society, based in educational strategies aiming both information about the virus and its prevention, as well as public awareness for safe sex practices or in stable or not intercourses

Parasitos de importância para a caprinocultura e a ovinocultura potiguar

The goat and sheep industry shows up as an agricultural activity of great importance for the semiarid Northeast. However, the sheep and goats production is made with various difficulties. Among them, parasitic infections, particularly helminth infections of the gastrointestinal tract, the eimeriosis and toxoplasmosis; this one related to problems in reproduction. For this reason, the aim of this study is to to make a survey of the occurrence and some determinants of parasitic diseases that affect small ruminant flocks of the microregions Natal, Macaíba, Litoral Sul, Angicos, Vale do Açu and Borborema Potiguar. Thereunto, epidemiological tools were applied with producers, keepers or guardians of herds and also held collections of blood and feces of animals in eight properties located in seven municipalities of these microregions. The parasite load of the animals was determined through eggs and oocysts counting per gram of feces EPG and OPG, respectively. In addition, the recovery of infective larvae was made. Blood samples were used to measure the globular cell volume and the search for anti-Toxoplasma gondii IgG in sheep serum, by Enzyme Linked Immune Sorbent Assay (ELISA). For categorical variables, the statistical analysis was performed using Poisson regression, with significance level of 0.05. The analysis of the instruments showed that ivermectin is the anthelmintic used in 85,71% of properties. From the total of feces samples of the sheep (n = 179), 53,07% were positive for helminth eggs and 48,04% were positive for oocysts of Eimeria. From the samples of faeces of goats (n = 133), 72,18% were positive for helminth eggs and 96,99% for oocysts of Eimeria. The lowest EPG and OPG count was observed in the micro region of Angicos. Most of the EPG count was found in the micro region Litoral Sul and the OPG count in the micro-region Borborema Potiguar. Both cases the difference was statistically significant(p- value0,000)The most prevalent helminth genus found was Haemonchus, present in 49,87% of the sheep and 80,42% of goats. The average of hematocrit ranged from 22,91 to 33,25 in sheep and from 22,62 to 28,25 in goats. The prevalence of anti-Toxoplasma gondii IgG ranged from 63,33% to 100,00%. The goats showed to be more susceptible to infections by parasites of the gastrointestinal tract than the sheep. In all the properties was observed high prevalence of infection by T. gondii, with the lowest percentages recorded in the micro regions Angicos and Borborema Potiguar.

Distribuição da fauna triatomínica e infecção natural pelo Trypanosoma cruzi em diferentes municípios do semiárido do Rio Grande do Norte

The triatomine fauna distribution and the natural infection by Trypanosoma cruzi was evaluated aiming the comprehension of the transmission dynamics of this parasite in the countryside of the State of Rio Grande do Norte. Additionally, the research for Trypanosoma rangeli was also investigated. The captures of triatomines were performed at sylvatic, peridomicile and domicile environments at different municipalities of the central and western mesoregions of this state. The insects were identified and examined by direct method, xenoculture and PCR to detect T. cruzi. The detection of T. rangeli was performed by direct examination of the hemolymph and multiplex PCR of 151 positive specimens for T. cruzi. Of 824 captured insects, the species were distributed in Triatoma brasiliensis (66.4%), Triatoma pseudomaculata (18.2%), Panstrongylus lutzi (12.7%) and Rhodnius nasutus (2.7%), and T. brasiliensis was found in most of the evaluated municipalities. The species were captured at nymph and adult stages, except P. lutzi, exclusively in adult stage. In the sylvatic environment were captured T. brasiliensis (57%), P. lutzi (28%) and T. pseudomaculata (15%) species. At the peridomicile environment were identified T. brasiliensis (74%), T. pseudomaculata (21%) and R. nasutus (5.0%), while in the intradomicile was found only T. brasiliensis. The infection rate of triatomines by T. cruzi was 30.4%, P. lutzi showed highest rate (78%), followed by T. brasiliensis (24.4%), T. pseudomaculata (22.6%) and R. nasutus (4.5%). Infected triatomines indexes at silvatic, peridomicile and domicile environments were of 41.8%, 20.1% and 50.0%, respectively. T. rangeli was only detected by multiplex PCR in 2.6% (4/151) of examined insects, of these 4.4% (3/67) were T. brasiliensis and 1.5% (1/63) P. lutzi species. The data showed that the positivity of P. lutzi allied to its ability to invade domicile attracted by light, suggests a likely participation of this insect between epidemiological transmission cycles of T. cruzi. T. brasiliensis was the only specie present in all environments, what reinforces its importance related to the capacity for adapting to the domestic environment, potential as a vector, and maintenance of sylvatic and domestic transmissions cycles in the semiarid, indicating the necessity of continuous epidemiological surveillance. The presence of T. rangeli in T. brasiliensis and P. lutzi was first recorded in rural zone of this State, broadening the area of occurrence of this protozoan in northeastern Brazil.

Distribuição da fauna triatomínica e infecção natural pelo Trypanosoma cruzi em diferentes municípios do semiárido do Rio Grande do Norte

The triatomine fauna distribution and the natural infection by Trypanosoma cruzi was evaluated aiming the comprehension of the transmission dynamics of this parasite in the countryside of the State of Rio Grande do Norte. Additionally, the research for Trypanosoma rangeli was also investigated. The captures of triatomines were performed at sylvatic, peridomicile and domicile environments at different municipalities of the central and western mesoregions of this state. The insects were identified and examined by direct method, xenoculture and PCR to detect T. cruzi. The detection of T. rangeli was performed by direct examination of the hemolymph and multiplex PCR of 151 positive specimens for T. cruzi. Of 824 captured insects, the species were distributed in Triatoma brasiliensis (66.4%), Triatoma pseudomaculata (18.2%), Panstrongylus lutzi (12.7%) and Rhodnius nasutus (2.7%), and T. brasiliensis was found in most of the evaluated municipalities. The species were captured at nymph and adult stages, except P. lutzi, exclusively in adult stage. In the sylvatic environment were captured T. brasiliensis (57%), P. lutzi (28%) and T. pseudomaculata (15%) species. At the peridomicile environment were identified T. brasiliensis (74%), T. pseudomaculata (21%) and R. nasutus (5.0%), while in the intradomicile was found only T. brasiliensis. The infection rate of triatomines by T. cruzi was 30.4%, P. lutzi showed highest rate (78%), followed by T. brasiliensis (24.4%), T. pseudomaculata (22.6%) and R. nasutus (4.5%). Infected triatomines indexes at silvatic, peridomicile and domicile environments were of 41.8%, 20.1% and 50.0%, respectively. T. rangeli was only detected by multiplex PCR in 2.6% (4/151) of examined insects, of these 4.4% (3/67) were T. brasiliensis and 1.5% (1/63) P. lutzi species. The data showed that the positivity of P. lutzi allied to its ability to invade domicile attracted by light, suggests a likely participation of this insect between epidemiological transmission cycles of T. cruzi. T. brasiliensis was the only specie present in all environments, what reinforces its importance related to the capacity for adapting to the domestic environment, potential as a vector, and maintenance of sylvatic and domestic transmissions cycles in the semiarid, indicating the necessity of continuous epidemiological surveillance. The presence of T. rangeli in T. brasiliensis and P. lutzi was first recorded in rural zone of this State, broadening the area of occurrence of this protozoan in northeastern Brazil.

Prevalence of haemosporidians in a Neotropical endemic bird area

Haemosporidians are vector-transmitted intracellular parasites that occur in many bird species worldwide and may have important implications for wild bird populations. Surveys of haemosporidians have traditionally focused on Europe and North America, and only recently have they been carried out in the Neotropics, where the prevalence and impacts of the disease have been less studied and are not well understood. In this study we carried out a survey in the endemic bird area of the Sierra Nevada de Santa Marta (SNSM), an isolated coastal massif in northern Colombia that contains a large number of biomes and that is experiencing high rates of habitat loss. We sampled birds from 25 species at 2 different altitudes (1640 and 2100 m asl) and determined avian haemosporidian infection by polymerase chain reaction and sequencing a portion of the cytochrome b (cyt b) gene of the parasite. From the sampled birds, 32.1% were infected by at least 1 of 12 unique cyt b lineages of haemosporidian genera: Plasmodium, Leucocytozoon, Haemoproteus, and subgenus Parahaemoproteus. We found a higher prevalence of avian haemosporidians at low altitudes (1640 m asl). All endemic bird species we sampled had at least one individual infected with avian haemosporidians. We also found evidence of higher overall prevalence among endemic rather than nonendemic birds, suggesting higher susceptibility in endemic birds. Overall, our findings suggest a high haemosporidian species richness in the bird community of the SNSM. Considering the rate of habitat loss that this area is experiencing, it is important to understand how avian haemosporidians affect bird populations; furthermore, more exhaustive sampling is required to fully comprehend the extent of avian haemosporidian infection in the area.

Effet préventif de la milrinone inhalée chez les patients avec hypertension pulmonaire subissant une chirurgie cardiaque sous circulation extracorporelle : une approche pharmacométrique

La circulation extracorporelle (CEC) est une technique utilisée en chirurgie cardiaque effectuée des milliers de fois chaque jour à travers le monde. L’instabilité hémodynamique associée au sevrage de la CEC difficile constitue la principale cause de mortalité en chirurgie cardiaque et l’hypertension pulmonaire (HP) a été identifiée comme un des facteurs de risque les plus importants. Récemment, une hypothèse a été émise suggérant que l'administration prophylactique (avant la CEC) de la milrinone par inhalation puisse avoir un effet préventif et faciliter le sevrage de la CEC chez les patients atteints d’HP. Toutefois, cette indication et voie d'administration pour la milrinone n'ont pas encore été approuvées par les organismes réglementaires. Jusqu'à présent, la recherche clinique sur la milrinone inhalée s’est principalement concentrée sur l’efficacité hémodynamique et l'innocuité chez les patients cardiaques, bien qu’aucun biomarqueur n’ait encore été établi. La dose la plus appropriée pour l’administration par nébulisation n'a pas été déterminée, de même que la caractérisation des profils pharmacocinétiques (PK) et pharmacodynamiques (PD) suite à l'inhalation. L'objectif de notre recherche consistait à caractériser la relation exposition-réponse de la milrinone inhalée administrée chez les patients subissant une chirurgie cardiaque sous CEC. Une méthode analytique par chromatographie liquide à haute performance couplée à un détecteur ultraviolet (HPLC-UV) a été optimisée et validée pour le dosage de la milrinone plasmatique suite à l’inhalation et s’est avérée sensible et précise. La limite de quantification (LLOQ) était de 1.25 ng/ml avec des valeurs de précision intra- et inter-dosage moyennes (CV%) <8%. Des patients souffrant d’HP pour lesquels une chirurgie cardiaque sous CEC était prévue ont d’abord été recrutés pour une étude pilote (n=12) et, par la suite, pour une étude à plus grande échelle (n=28) où la milrinone (5 mg) était administrée par inhalation pré-CEC. Dans l'étude pilote, nous avons comparé l'exposition systémique de la milrinone peu après son administration avec un nébuliseur pneumatique ou un nébuliseur à tamis vibrant. L’efficacité des nébuliseurs en termes de dose émise et dose inhalée a également été déterminée in vitro. Dans l'étude à plus grande échelle conduite en utilisant exclusivement le nébuliseur à tamis vibrant, la dose inhalée in vivo a été estimée et le profil pharmacocinétique de la milrinone inhalée a été pleinement caractérisé aux niveaux plasmatique et urinaire. Le ratio de la pression artérielle moyenne sur la pression artérielle pulmonaire moyenne (PAm/PAPm) a été choisi comme biomarqueur PD. La relation exposition-réponse de la milrinone a été caractérisée pendant la période d'inhalation en étudiant la relation entre l'aire sous la courbe de l’effet (ASCE) et l’aire sous la courbe des concentrations plasmatiques (ASC) de chacun des patients. Enfin, le ratio PAm/PAPm a été exploré comme un prédicteur potentiel de sortie de CEC difficile dans un modèle de régression logistique. Les expériences in vitro ont démontré que les doses émises étaient similaires pour les nébuliseurs pneumatique (64%) et à tamis vibrant (68%). Cependant, la dose inhalée était 2-3 fois supérieure (46% vs 17%) avec le nébuliseur à tamis vibrant, et ce, en accord avec les concentrations plasmatiques. Chez les patients, en raison des variations au niveau des facteurs liés au circuit et au ventilateur causant une plus grande dose expirée, la dose inhalée a été estimée inférieure (30%) et cela a été confirmé après récupération de la dose de milrinone dans l'urine 24 h (26%). Les concentrations plasmatiques maximales (Cmax: 41-189 ng/ml) et l'ampleur de la réponse maximale ΔRmax-R0 (0-65%) ont été observées à la fin de l'inhalation (10-30 min). Les données obtenues suite aux analyses PK sont en accord avec les données publiées pour la milrinone intraveineuse. Après la période d'inhalation, les ASCE individuelles étaient directement reliées aux ASC (P=0.045). Enfin, notre biomarqueur PD ainsi que la durée de CEC ont été identifiés comme des prédicteurs significatifs de la sortie de CEC difficile. La comparaison des ASC et ASCE correspondantes a fourni des données préliminaires supportant une preuve de concept pour l'utilisation du ratio PAm/PAPm comme biomarqueur PD prometteur et justifie de futures études PK/PD. Nous avons pu démontrer que la variation du ratio PAm/PAPm en réponse à la milrinone inhalée contribue à la prévention de la sortie de CEC difficile.

The Burkholderia Cenocepacia OmpA-Like Protein BCAL2958: Identification, Characterization, and Detection of Anti-BCAL2958 Antibodies in Serum from B. Cepacia Complex-Infected Cystic Fibrosis Patients

Respiratory infections by bacteria of the Burkholderia cepacia complex (Bcc) remain an important cause of morbidity and mortality among cystic fibrosis patients, highlighting the need for novel therapeutic strategies. In the present work we have studied the B. cenocepacia protein BCAL2958, a member of the OmpA-like family of proteins, demonstrated as highly immunogenic in other pathogens and capable of eliciting strong host immune responses. The encoding gene was cloned and the protein, produced as a 6× His-tagged derivative, was used to produce polyclonal antibodies. Bioinformatics analyses led to the identification of sequences encoding proteins with a similarity higher than 96 % to BCAL2958 in all the publicly available Bcc genomes. Furthermore, using the antibody it was experimentally demonstrated that this protein is produced by all the 12 analyzed strains from 7 Bcc species. In addition, results are also presented showing the presence of anti-BCAL2958 antibodies in sera from cystic fibrosis patients with a clinical record of respiratory infection by Bcc, and the ability of the purified protein to in vitro stimulate neutrophils. The widespread production of the protein by Bcc members, together with its ability to stimulate the immune system and the detection of circulating antibodies in patients with a documented record of Bcc infection strongly suggest that the protein is a potential candidate for usage in preventive therapies of infections by Bcc.

CURB-65 and Other Markers of Illness Severity in Community-Acquired Pneumonia Among HIV-Positive Patients

As the relative burden of community-acquired bacterial pneumonia among HIV-positive patients increases, adequate prediction of case severity on presentation is crucial. We sought to determine what characteristics measurable on presentation are predictive of worse outcomes. We studied all admissions for community-acquired bacterial pneumonia over one year at a tertiary centre. Patient demographics, comorbidities, HIV-specific markers and CURB-65 scores on Emergency Department presentation were reviewed. Outcomes of interest included mortality, bacteraemia, intensive care unit admission and orotracheal intubation. A total of 396 patients were included: 49 HIV-positive and 347 HIV-negative. Mean CURB-65 score was 1.3 for HIV-positive and 2.2 for HIV-negative patients (p < 0.0001), its predictive value for mortality being maintained in both groups (p = 0.03 and p < 0.001, respectively). Adjusting for CURB-65 scores, HIV infection by itself was only associated with bacteraemia (adjusted odds ratio [AOR] 7.1, 95% CI [2.6-19.5]). Patients with < 200 CD4 cells/µL presented similar CURB-65 adjusted mortality (aOR 1.7, 95% CI [0.2-15.2]), but higher risk of intensive care unit admission (aOR 5.7, 95% CI [1.5-22.0]) and orotracheal intubation (aOR 9.1, 95% CI [2.2-37.1]), compared to HIV-negative patients. These two associations were not observed in the > 200 CD4 cells/µL subgroup (aOR 2.2, 95% CI [0.7-7.6] and aOR 0.8, 95% CI [0.1-6.5], respectively). Antiretroviral therapy and viral load suppression were not associated with different outcomes (p > 0.05). High CURB-65 scores and CD4 counts < 200 cells/µL were both associated with worse outcomes. Severity assessment scales and CD4 counts may both be helpful in predicting severity in HIV-positive patients presenting with community-acquired bacterial pneumonia.

Distribuição dos metais nas poeiras colhidas em Estarreja: estudo da mobilidade e impacto potencial dos metais no ambiente

As poeiras urbanas, vulgarmente designadas na literatura por street dusts ou road dusts, são misturas heterogêneas de partículas minerais do solo e partículas resultantes do tráfego, formando um material com características únicas e específicas de cada local. Estas partículas, geralmente enriquecidas com elementos potencialmente tóxicos, quando inaladas ou ingeridas poderão ser um risco para a saúde das populações. Neste trabalho foram recolhidas 21 amostras de poeiras urbanas na cidade de Estarreja assim como amostras representativas de partículas relacionados com o tráfego (poeiras resultante do desgaste dos travões e das marcações dos pavimentos e estradas) com o objetivo de investigar a contribuição relativa destas partículas no comportamento geoquímico dessas amostras e o risco associado para as populações locais. Para a concretização do objetivo proposto caracterizou-se química e mineralogicamente as amostras de poeiras urbanas e as partículas relacionadas com o tráfego e avaliou-se a disponibilidade e bioacessibilidade para três elementos considerados potencialmente tóxicos (Cu, Pb e Zn) usando uma combinação de ensaios: (a) digestão ácida; (b) extração sequencial para identificar o fracionamento do Cu, Pb e Zn nas diferentes fases-suporte dos metais, e (c) bioaccessibilidade oral in vitro. Os resultados da análise química mostram que as poeiras dos travões apresentam concentrações elevadas em Fe, Cu, Zn, Mn, Ba, Sb, Cr e Ni sendo de referir diferenças composicionais significativas entre as amostras estudadas. A amostra de tinta contém teores elevados de Ba, Ca, Ti e Pb e também pode conter outros elementos tais como Co, Cr, Cu, Mn. Mineralogicamente constata-se que as amostras de poeiras dos travões tem uma composição mineralógica semelhante mostrando que são constituídas por uma elevada percentagem de material de baixa cristalinidade, grafite e óxidos/hidróxidos de Fe amorfos. A amostra de tinta de marcação dos pavimentos das estradas é composta por material mais cristalino do que a poeira dos travões e é essencialmente constituída por carbonatos (maioritariamente dolomite) e também por barite (em menor quantidade). Os resultados obtidos nas amostras de poeiras urbanas indicam a existência de associações de elementos que definem claramente a componente geogénica e/ou antropogénica e apontam para diferenças entre essas associações nas duas frações estudadas (250 m e 63 m). A heterogeneidade das poeiras é revelada pela existência de partículas com origem geogénica (por exemplo quartzo e aluminossilicatos), de partículas com características marcadamente antropogénicas (partículas enriquecidas em Fe, Pb, Zn e Cu) ou ainda de partículas com origem mista (óxidos de Fe e Ti). Os resultados da extração química seletiva sequencial permitiu concluir que, nas amostras em estudo, as fases de troca e ácido-solúveis são as fases suporte mais importantes para o Cu, Pb e Zn Os resultados dos ensaios de bioacessibilidade mostraram também que uma percentagem significativa de Cu, Pb e Zn total está disponível para absorção gástrica. Este estudo destaca também a necessidade de se caracterizar em detalhe as propriedades intrínsecas das partículas antrópicas presentes nas poeiras urbanas, de forma a compreender as variações da fração bioacessível nos diferentes elementos estudados assim como nas diferentes frações.

Determination of soybean cultivar resistance to soybean cyst nematode with quantitative polymerase chain reaction

Heterodera glycines, the soybean cyst nematode, is the major pathogen of Glycine max (soybean). Effective management of this pathogen is contingent on the use of resistant cultivars, thus screening for resistant cultivars is essential. The purpose of this research was to develop a method to assess infection of soybean roots by H. glycines with real-time quantitative Polymerase Chain Reaction (qPCR), a prelude to differentiation of resistance levels in soybean cultivars. Two experiments were conducted. In the first one, a consistent inoculation method was developed using to provide active second-stage juveniles (J2). Two-day-old soybean roots were infested with 0 and 1000 J2/mL. Twenty-four hours after infestation, the roots were surface sterilized and DNA was extracted with the DNA FastKit (MP Biomedicals, Santa Ana, CA)). For the qPCR assay, primer pair for single copy gene HgSNO, which codes for a protein involved in the production of vitamin B6, was selected for H. glycines DNA amplification within soybean roots. In the second experiment, compatible Lee 74, incompatible Peking and cultivars with different levels of resistance to H. glycines were inoculated with 0 and 1,000 J2/seedlings. Twenty-four hours post inoculation they were transplanted into pasteurized soil. Subsequently they were harvested at 1, 7, 10, 14 and 21 days post inoculation for DNA extraction. With the qPCR assay, the time needed to differentiate highly resistant cultivars from the rest was reduced. Quantification of H. glycines infection by traditional means (numbers of females produced in 30 days) is a time-consuming practice; the qPCR method can replace the traditional one and improve precision in determining infection levels.