Molluscicidal activity of Physalis angulata L. extracts and fractions on Biomphalaria tenagophila (d'Orbigny, 1835) under laboratory conditions

The main objective of this research is to evaluate the molluscicide activity of Physalis angulata L. Biomphalaria tenagophila specimens under laboratory conditions. Extracts and fractions were supplied by the Laboratório de Química de Produtos Naturais, Farmanguinhos-Fiocruz. Experiments were performed according to the methodology described by the World Health Organization for molluscicide tests using the concentrations from 0.1 to 500 mg/l of the extracts, fractions and of a pool of physalins modified steroids present in this species. The results show that ethyl acetate and acetone extracts from the whole plant, the ethanolic extracts of the roots and the physalins pool from stems and leaves were active. Only the whole plant extracts were available in sufficient quantity for the determination of LD50 and LD90 values.

Cultivar, harvest year, and storage conditions affecting nutritional quality of common beans (Phaseolus vulgaris L.

Sixteen common bean cultivars were compared concerning the physicochemical characteristics of their raw seeds in the course of two consecutive harvests, as well as the effect of storage conditions on starch and dietary fiber content of cooked beans. Using cluster analysis it was possible to identify groups of cultivars with different nutritional features. Bean cultivars were categorized into four different groups according either to their macronutrient content (crude protein-PROT, total dietary fiber-TDF, insoluble dietary fiber-IDF, soluble dietary fiber-SDF, digestible starch-DS, and resistant starch-RS) or to their micronutrient levels (Fe, Zn, Mn, Cu, Ca, Mg, and P). Guateian 6662 and Rio Tibagi appeared to be the most suitable cultivars to prevent nutritional deficiencies, because they had high PROT, DS, Fe, and Zn content. The high total dietary fiber and RS content of Iraí, Minuano, and TPS Bonito cultivars, and specially the high soluble fiber content of Guateian 6662 and Rio Tibagi cultivars suggests that they could have a beneficial role in controlling blood lipid and glucose levels. Cooked beans had a decrease in DS and an increase in RS content after storage (4 °C or -20 °C), but these changes were more prominent in beans that had low RS content before cooking than in those of high RS content. TDF, IDF, and SDF did not change after storage.

Influence of leaf retention on cutting propagation of Lavandula dentata L.

Vegetative propagation of lavender offers several advantages over sexual propagation, among them crop homogeneity and yield of higher quality essential oil. However, Lavandula species have been propagated mostly by seeds and are said to be recalcitrant to rooting when propagated by cuttings. During cutting propagation, one of the important variables that influence the rooting capacity of cuttings is the leaf retention. The objective of this work was to evaluate the influence of leaf retention on rooting of L. dentata cuttings. Apical cuttings of L. dentata of 10 cm in length, keeping approximately 1/3, 1/2 or 2/3 of their leaves were planted in commercial substrate Plantmax HT® under intermittent mist. After two months, averages of root number, length of the longest root, root fresh and dry weights, and the survival percentage were evaluated. Root length and fresh weight were statistically greater with 2/3 of leaf retention and when fewer leaves were kept on the cuttings, lower means of root dry weight was observed. Under the conditions applied in this study, greater leaf retention was better for rooting of L. dentata cuttings.

Growth and yield of Coffea arabica L. in Northwest Fluminense: 2nd harvest

In recent years, several new coffee cultivars recommended for different regions have been released. However, the performance of these varieties in many traditionally producing regions is unknown. Difference of climate and soil may jeopardize the productivity of the new cultivars and cause losses to farmers. The objective of this study is to evaluate the vegetative growth and productive genotypes of C. arabica in the conditions of the Northwestern Rio de Janeiro State, Brazil. The experiment was settled in 2007, in Panorama 1 Farm, located in the municipality of Varre Sai, RJ. Twenty-five genotypes of C. arabica were planted in a spacing of 2.5 × 0.8 m, using a completely randomized design with five replications and eight plants per plot. There were eight measurements of vegetative growth represented by plant height, stem diameter and number of plagiotropic branches. Assessments of productivity were also performed in years 2009 and 2010. There was a positive phenotypic correlation among vegetative characteristics and between vegetative characteristics and yield in the first harvest, while in the second harvest only the number of plagiotropic branches was positively correlated with yield. Up to date, the genotypes Catucaí amarelo 2 SL, Catiguá MG 02, Acauã, Palma II, Sabiá 398, IPR 103/ Iapar, IPR 100/Iapar, H 419-10-6-2-12-1, Catucaí amarelo 24 / 137, Iapar 59, Catucaí amarelo 20/15, H 419-10-6-2-5-10-1 and H 419-10-6-2-5-1 had the highest average yield after two harvests.

Response of rice cultivars to nitrogen in upland conditions

Against the background of a growing world population, rice (Oryza sativa L.) consumption is expected to grow faster than its production. Therefore, an appropriate question would be: how to increase productivity in the short-term? In this respect, it becomes important the implementation of modern agricultural production systems, such as upland rice with supplemental sprinkler irrigation. Additional information is needed to maximize the available resources, with special attention given to research on the use of nitrogen. This study aimed to evaluate the agronomic performance of commercial rice cultivars with different plant characteristics in upland conditions with supplemental sprinkler irrigation, when subjected to nitrogen in topdress application at the R1 stage (panicle differentiation). The experiment was arranged in a randomized block with split plot design, with 65 treatments, consisting of the combination of 13 cultivars in the plots, and five nitrogen levels in the subplots (0, 40, 80, 120 and 160 kg ha-1), with four replications. Genetic variability was detected among rice cultivars and the agronomic performance in response to the applied nitrogen. The topdressing application of nitrogen increases, in general, the production components and grain yield in rice. Cultivars BRS Primavera, Caiapó and IAC 202 stood out for grain yield, followed by Baldo, Carnaroli, BRS Curinga and IAC 500 with lower yields.

Shape and size of jatropha beans (Jatropha curcas L.) during drying at different temperatures

This study was carried out to study the physical properties of the jatropha beans over the drying under six air conditions, based on measurements of roundness, sphericity, volume, superficial area, projected area and surface/volume ratio. Jatropha beans with moisture content around 0.61 (decimal d.b.) were subjected to thin-layer drying in oven with forced-air circulation under six temperature conditions (36, 45, 60, 75, 90 and 105 °C) and relative humidity of 31.7; 19.6; 9.4; 4.8; 2.6 and 1.5% respectively, until reaching the moisture content of 0.11 ± 0.006 (decimal d. b.). The results showed that the necessary time for jatropha beans to reach the moisture content of 0.11 ± 0.006 (decimal d.b.) were 1.5; 2.25; 3.0; 4.75; 6.75 and 12.0 h for the drying temperatures of 105, 90, 75, 60, 45 and 36 °C, respectively; and the reduction in the moisture content as well as the drying conditions promoted changes in the shape and reduced the size of the jatropha beans.

Cantaloupe melon ( Cucumis melo L.) conservation using hydrocooling

ABSTRACT Maintaining cantaloupe melon at field temperature impairs conservation as it speeds up cell metabolism and transpiration, and, consequently, reduces shelf life. This study aimed to evaluate the conservation of Torreon hybrid cantaloupe using the hydrocooling treatment. Fruits were harvested at the commercial maturity stage (60 days after planting), in the morning, at the Nova California Farm, municipality of Mossoró-RN, in September 2007. One set of fruit was immersed in chilled water at 5 ºC for 5 min, at the packing house, while the remaining set was not hydro cooled. Then, both sets (treated and untreated with hydrocooling) were pre-cooled in air forced tunnels at 7 ºC, until the temperature in the pulp reached 10 ºC. Both fruit sets were stored for 0, 14, 21, 28 and 35 days under modified atmosphere at 3 ± 1 oC and 90 ± 5% RH. After each storage period, the fruits were incubated in an atmosphere-controlled chamber at 20 ± 2 oC and 80 ± 5% de RH, for seven days. The following characteristics were evaluated: external and internal appearance, mass loss, soluble solids, firmness and titrable acidity. The experiment was arranged in a completely randomized split-plot design with four replications of three fruits. The plots consisted of the hydrocooling conditions (with and without fruit soaking in chilled water), and the sub-plots consisted of the storage times (0, 14, 21, 28 and 35 days).The treatment with hydrocooling was efficient in keeping the firmness and soluble solids of the fruits and shortened the pre-cooling time in the cooling tunnel. However, hydrocooling did not increase fruit shelf-life.

Lethality of triatomines (Hemiptera: Reduviiae), vectors of Chagas' disease, feeding on blood baits containing synthetic insecticides, under laboratory conditions

A laboratory study was conducted to test the toxicity of synthetic insecticides added to defibrinated sheep blood kept at room temperature and offered as food to the following triatomine species: Triatoma infestans, Panstrongylus megistus, Triatoma vitticeps, Triatoma pseudomaculata, Triatoma brasiliensis and Rhodnius prolixus. The insecticides used, at a concentration of 1g/l, were: HCH, DDT, Malathion and Trichlorfon, and the lethalithy observed at the end of a 7-day period varied according to the active principle of each. HCH was the most effective by the oral route, killing 100% of the insects, except P. megistus (95.7%) and T. pseudomaculata (94.1%). Trichlorfon killed the insects at rates ranging from 71.8% (T. vitticeps) to 98% (R. prolixus). Malathion was slightly less efficient, killing the insects at rates from 56.8% (T. vitticeps) to 97% (T.brasiliensis). DDT was the least effective, with a killing rate of 10% (T. vitticeps) to 75% (T.brasiliensis). Since the tests were performed at room temperature, we suggest that baits of this type should be tried for the control of triatomines in the field.

Lethal effect of a bait for Rhodnius prolixus (Hemiptera: Reduviidae), the vector of Chagas' disease, containing hexachlorocyclohexane (HCH), under laboratory conditions

The lethal effect of a bait containing an aqueous hexachlorocyclohexane (HCH) suspension at the concentration of 1g/l and maintained at room temperature was studied in the laboratory over a period of 12 weeks. The suspension was placed in a latex bag hanging inside a 1000-ml beaker tightly covered with nylon netting, and left there with no changes for 85 days. Sixteen groups of R. prolixas bugs, consisting on average of 30 specimens each, were successively exposed to the bait and observed at different intervals for one week each. The mortality rate was 100% for all groups, except for the 16th, whose mortality rate was 96.7%. As the groups succeeded one another, mortality started to occur more rapidly and was more marked at the 6- and 24-h intervals. Later tests respectively started at 6:00 a.m. and 6:00 p.m. showed that diurnal and nocturnal periodicity in the offer of food had no effect on mortality. First- and 2nd- instar nymphs and adults male were more sensitive and 5th- instar nymphs were more resistant to the active principle of the bait.

Prevalence of anti-hepatits A antibodies in children of different socioeconomic conditions in Vila Velha, ES

This report describes the prevalence of anti-HAV antibodies in children from elementary school in the Municipality of Vila Velha, ES, Brazil. Anti-HAV antibodies were investigated by ELISA method in the serum of 606 children (four to fourteen years old) from three elementary schools, located in neighborhoods with varying household monthly income levels: São José School, 200 chidren, household income higher than US$700; São Torquato School, 273 children, US$200 to 300; and Cobi School, 133 children, less than US$200. From each children data on age, gender, skin color, sanitary conditions, frequency of contact with sea or river water and family history of hepatitis were recorded. Anti-HAV antibodies were present in 38.6% of all children, 9% in São José School, 49.1% in São Torquato School and 61.7% in Cobi School. Logistic regression analysis demonstrated a positive correlation of positive anti-HAV test with age, non white color of the skin, absence of sewage treatment and domestic water filter, and a past history of hepatitis. The prevalence of anti-HAV antibodies in school children in Vila Velha, ES, was lower than that observed in the same age group in North and Northeast Brazil and was significantly higher in children from families with low socioeconomic status. In addition the results indicate a changing epidemiologic pattern of hepatitis A in our country, with an increasing number of children and adolescents with high risk for HAV infection, mainly in high socioeconomic class. A consideration must be given to the feasibility of vaccination programs for children and adolescents in our country.

Susceptibility of Aedes aegypti (L) to the insect growth regulators diflubenzuron and methoprene in Uberlândia, State of Minas Gerais

Aedes aegypti (L) (Diptera: Culicidae) was reared in several concentrations of diflubenzuron and methoprene under laboratory conditions in Uberlândia, State of Minas Gerais, southeastern Brazil. Characteristics such as LC50 and LC95, the susceptibility of immature stages of different ages to these insect growth regulators and their residual effects were studied. The LC50 and LC95 of diflubenzuron and methoprene were 5.19 and 12.24 ppb; 19.95 and 72.08 ppb, respectively. While diflubenzuron caused great mortality in all larval instars, methoprene was more effective when the mosquito was exposed from the start of the fourth larval instar onwards. Commercial concentrations of these two insect growth regulators close to LC95 presented greater residual activity than did their respective technical formulations. The parameters were compared with those obtained elsewhere. The characteristics investigated here indicate that these insect growth regulators are effective alternatives for controlling the dengue vector in the Uberlândia region.

Ecoepidemiology and biology of Eratyrus mucronatus Stål, 1859 (Hemiptera: Reduviidae: Triatominae), a sylvatic vector of Chagas disease in the Brazilian Amazon

Introduction Eratyrus mucronatus Stål, 1859 is a wild triatomine vector of Trypanosoma cruzi Chagas, 1909. However, little is known regarding the biology and ecoepidemiology of this triatomine in the Brazilian Amazon. The present study describes the biology of E. mucronatus grown under laboratory conditions and the epidemiological aspects of its natural breeding sites. Methods Five colonies were monitored in the field for 3 years. Temperature and humidity measurements were taken in the mornings and afternoons at the natural breeding sites, and the behavior and distribution of the nymphs and adults were observed in the wild colony. We also monitored the life cycle under controlled laboratory conditions. Results Some factors that were considered decisive for the establishment of these colonies were present at all of the colonies studied in the field. These factors included an active termite nest, a vertebrate for repast, and dry and shaded substrates with temperatures of 24-28°C and with humidity of 80-90%. A generation was developed in 274 days under these microclimatic conditions in the laboratory. Conclusions The climatic variables described in the field indicate that these environmental parameters have a limiting effect on the dispersal and colonization of E. mucronatus to new environments. In addition, the long period of development to adulthood demonstrates that only one generation can develop per year even under the more favorable laboratory conditions.

Changes in the amount of soluble carbohydrates and polyphenols contents during decomposition of Montrichardia arborescens (L.) Schott

This study describes the aerobic and anaerobic decay of soluble carbohydrates (CH) and polyphenols (PH) during decomposition of Montrichardia arborescens. Plant and water samples were collected in the Cantá stream (2º 49' 11" N and 60º 40' 24" W), Roraima, Brazil. Decomposition chambers with plant fragments and stream water were incubated. Particulate organic matter was separated from dissolved organic matter and concentrations of CH and PH were determined. The results were fitted to 1st order kinetics models. CH and PH comprised a labile fraction (LCH and LPH) and a refractory fraction (RCH and RPH). The global coefficient associated with LCH weight loss was 1.4 times higher under aerobic conditions (3.4 day-1) higher than for anaerobic conditions. On the other hand, the RCH decay rate in the anaerobic process (0.0074 day-1) was 1.39 times higher. LCH was estimated to be 92% while RCH amounted to 8%. The LPH anaerobic decay was 5.2 times the value for the aerobic decay (0.67 day-1). For both conditions, RPH decay coefficients were similar (» 0.011 day-1). In the aerobic experiments LPH and RPH corresponded to 92.5% and 7.5%, respectively. For the anaerobic process these contents were 85.5% and 14.5%, respectively. From these results, we concluded that in the Cantá stream, the anaerobic degradation of phenols is more efficient than the aerobic counterpart. The aerobic condition provides a faster decay of carbohydrates of this plant.

Contribution to Early Holocene vegetation and climate history of Eastern Orinoco Llanos, Venezuela, from a paleoecological record of a Mauritia L.f. swamp

A palynological analysis of an organic paleosol found at 150-125 cm depth in a Mauritia swamp from the Eastern Orinoco Llanos is presented. The 25 cm pollen record summarizes the vegetation history during the Early Holocene, from 10,225 to 7,800 calendar yr BP. The vegetation was characterized by a Poaceae marsh, where Asteraceae, Melastomataceae, Schefflera-type and Phyllanthus were the most abundant shrubs and trees. Pollen-types richness was lower than that recorded today in similar environments, and Mauritia pollen was absent. Results suggest that climate was as humid as present during the beginning of the Holocene, with a decreasing trend in humidity from around 8,000-7,000 yr BP, in coincidence with the beginning of the "Early-Mid-Holocene Dryness" that affected deeply the Amazon Basin and neighboring areas. Dry climatic conditions could have existed in the study site until the Mid-Late Holocene when a Mauritia swamp developed, and humid conditions similar to present established. Main climate phases inferred in our study site fit well with regional trends recorded in other places located north Amazon Basin. However, conclusions are still limited by the lack of additional Quaternary records in the Orinoco Llanos area, avoiding regional correlations.