Humoral response (IgG) of goats experimentally infected with Fasciola hepatica against cysteine proteinases of adult fluke

The use of cysteine proteinases from Fasciola hepatica adult flukes for the serodiagnosis of caprine fasciolosis by means of an indirect ELISA test was studied. Two proteolytic fractions from adult fluke homogenates, with apparent molecular weights of 28 and 34 kDa (P28 and P34 respectively), were characterised as cysteine proteinases using azocasein assays and gelatin gel analysis. Both P28 and P34 fractions were electroluted and used as antigens in two different indirect ELISA tests. Serum IgG levels against P28 and P34 in goats given an experimental primary infection with 200 metacercariae or in goats given two experimental infections with 200 metacercariae were determined and compared with those observed in an uninfected control group. ELISA tests using both cysteine proteases showed a rapid and consistent detection of specific IgG in all experimentally infected goats. The IgG response to P28 was the first to be detected as early as 2-3 weeks post-infection and remained elevated throughout the experiment. The response to P34 was detected later (4-6 wpi) and disappeared in some animals at 18 wpi, while flukes were still present in the bile ducts. No significant differences were observed between the anti-P28 and anti-P34 IgG responses between animals receiving a primary or a challenge infection. The results of our study, although preliminary, are promising since the P28 ELISA described here may be a reliable method for the immunodiagnosis of F. hepatica infection in goats.     

Evaluation of 65% permethrin spot-on for prevention of canine visceral leishmaniasis: effect on disease prevalence and the vectors (Diptera: Psychodidae) in a hyperendemic area

A study was designed to examine the effect of 65% permethrin spot-on on the prevalence of canine visceral leishmaniasis and the abundance of sand flies in two neighborhoods in Corumbá, Mato Grosso do Sul, Brazil known to have a high prevalence of visceral leishmaniasis. An enrollment survey was conducted to determine the prevalence of visceral leishmaniasis. Area residents were provided with information about the project; the study area was defined, and all dogs (160 in Cristo Redentor and 230 in Popular Velha) identified in the study area were enrolled. Three 65% permethrin spot-on treatments (June 15-25, July 13-15, and August 10-12) were administered to 150, 110, and 99 dogs, respectively, in Popular Velha, according to label recommendations. Dogs in Cristo Redentor were untreated controls. Visceral leishmaniasis was diagnosed periodically by indirect immunofluorescence assay. A reduction in canine visceral leishmaniasis prevalence was observed at the Popular Velha site. The infection rate for treated dogs 1 month following the final treatment was approximately 50% reduced from that observed before treatment(19.3% vs 9.6%). Conversely, the infection rate at the control site was more than 80% higher at the September sampling than that observed pretreatment (4.1% vs 7.4%). Similar numbers of sand flies were captured and identified from both sites throughout the study. The results suggest that regular use of 65% permethrin during months of high risk for canine visceral leishmaniasis can be a useful strategy for reducing the prevalence of this disease in hyperendemic areas. It should be stressed, however, that the success of this strategy depends not only on the efficacy of the product itself but also on the adoption of other control measures and on economic variables, considering the low purchasing power of the populations living in higher-risk neighborhoods.     

Flea species from dogs in three cities of Chile

The purpose of this study was to establish the pattern of flea infestation in dogs in the cities of Santiago (33 degrees latitude south, 70 degrees longitude west), Concepción (36 degrees latitude south, 73 degrees longitude west) and Osorno (40 degrees latitude south, 73 degrees longitude west), located in different parts of Chile. The only species of fleas found on dogs from the three cities were Ctenocephalides felis felis (41.8%), Ctenocephalides canis (39.4%) and Pulex irritans (18.8%). Although the three species were found in the three cities, differences regarding their frequencies were detected (p<0.05). C. felis was the predominant species found on dogs in Santiago (80.5%). In Concepción, their frequencies followed a similar trend. However in Osorno, the most southern city, the predominant species was C. canis (78.7%).     

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Interactions between Plasmopara helianthi, Glomus mosseae and Two Plant Activators in Sunflower Plants

Interactions between Plasmopara helianthi, Glomus mosseae and two plant activators DL--amino-n-butyric acid (BABA) and CGA 245704 (acibenzolar-S-methyl (BTH)) in sunflower plants susceptible to downy mildew were studied in four experiments using different methods of treatment and pathogen inoculation. Both chemicals were applied as soil drenches and foliar sprays, whereas P. helianthi infection was obtained by root and cotyledon inoculations of the seedlings. Soil drenches at the rates of 50 and 100mgkg^–1 soil of BABA and BTH given 1 and 3 days before P. helianthi inoculation, respectively to mycorrhizal plants, provided moderate protection against the pathogen (about 50–55%). Morphological changes and decrease in mycorrhizal colonization in roots of BTH-treated plants and in BTH-treated mycorrhizal plants were also observed. Delay in the emergence and reduction of the root systems were more evident at the highest concentration but decreased with time. These effects were absent with the BABA treatment.Foliar spray treatment of BABA and BTH, applied at 4000 and 200µgml^–1, respectively (1 day post-inoculation) to mycorrhizal plants provided good protection (about 80%) against P. helianthi foliar infections. No effects on mycorrhizal colonization or on root systems were observed. In vitro tests on the effect of the compounds on the mycorrhizal fungus showed that the germination of G. mosseae sporocarps increased with BABA treatment whereas it was greatly inhibited by BTH treatment.     

Improvements in somatic embryogenesis protocol in Feijoa (Acca sellowiana (Berg) Burret): Induction,conversion and synthetic seeds

Pineapple guava (Acca sellowiana) syn. Feijoa sellowiana, a Brazilian indigenous Myrtaceae is under domestication in South Brazil. Previous works showed that this species is responsive to somatic embryogenesis and recalcitrant to conventional methods of clonal propagation. In the present work it was evaluated the role of components of culture medium in the induction and development of somatic embryos. The technology of synthetic seeds was also evaluated. Zygotic embryos were inoculated in LPm medium supplemented with 8 mM glutamic acid and 8 mM l-glutamine, 2,4-dichlophenoxiacetic acid (20 μM) and myo-inositol. For conversion of somatic embryos and synthetic seeds it was tested the effect of 6-benzylaminopurine and gibberellic acid combined or not with activated charcoal. The highest values for embryogenetic induction (100%) and number of somatic embryos/explant (113) were observed in the LPm medium supplemented with Glu (8 mM), and 2,4-D. The culture medium supplemented with BA (0.5 μM) and GA₃ (1 μM) and activated charcoal (1.5 g L⁻¹) enhanced the conversion of somatic embryos to plantlets. Pre-germinated somatic embryos encapsulated in sodium alginate with BA (0.5 μM) and GA₃ (1 μM) developed radicles. The use of synthetic seed was a requisite for the survival of plantlets.     

<Emphasis Type="Italic">In vitro</Emphasis> screening for sunflower (<Emphasis Type="Italic">Helianthus annuus</Emphasis>L.) resistant calli to <Emphasis Type="Italic">Diaporthe helianthi</Emphasis> fungal culture filtrate

Diaporthe helianthi the causal agent of sunflower (Helianthus annuus) stem canker, causes significant reductions in yield and oil content in most sunflower-growing areas. With the aim of enhancing host resistance, we selected in vitro sunflower calli against culture filtrates of two pathogen isolates (7/96 and 101/96). This technique may be an effective and rapid tool to discriminate the most virulent D. helianthi isolate and to screen for host resistance in the early stage of a breeding programme. Further investigation on the mechanisms involved in defence pathways showed no induction of salicylic acid and pathogenesis-related proteins in calli, indicating that the host resistance is not associated with Systemic Acquired Resistance but probably other biochemical mechanisms.     

Determination of free and bound phenolic compounds in buckwheat spaghetti by RP-HPLC-ESI-TOF-MS: effect of thermal processing from farm to fork

Nowadays there is considerable interest in the consumption of alternative crops as potential recipes for gluten-free products production. Therefore, the use of buckwheat for the production of gluten-free pasta has been investigated in the present study. RP-HPLC-ESI-TOF-MS has been applied for the separation and characterization of free and bound phenolic compounds in buckwheat flour and buckwheat spaghetti. Thus, 32 free and 24 bound phenolic compounds in buckwheat flour and spaghetti have been characterized and quantified. To the authors' knowledge, protochatechuic-4-O-glucoside acid and procyanidin A have been detected in buckwheat for the first time. The results have demonstrated a decrease of total free phenolic compounds from farm to fork (from flour to cooked spaghetti) of about 74.5%, with a range between 55.3 and 100%, for individual compounds. The decrease in bound phenols was 80.9%, with a range between 46.2 and 100%. The spaghetti-making process and the cooking caused losses of 46.1 and 49.4% of total phenolic compounds, respectively. Of the total phenolic compounds present in dried spaghetti, 11.6% were dissolved in water after cooking.