Estudo da ação do moluscocida (Bayluscide-SRB) da Dynatech R/D Company em lagos do nordeste brasileiro - Sergipe, Brasil

To study the action of molluscicide nine ponds were selected: 3 of them lying in Maruim municipality, 29 km far from north Aracaju, the State capital, and 6 ponds in Itabaianinha municipality, 118 km far from south Aracaju. This study was carried out for 16 months. Environmental parameters observed were those thought to have any influence on the planorbids and/or the molluscicide: water temperature, transparence, salinity, pH, dissolved oxygen, CO2, and the nutrients-phosphorus, nitrogen, potassium and calcium. Plancton microorganisms were also considered to observe Bayluscide action on them. SRB was used in a concentration of 6.25 kg per 1.000 [cubic metres] water, to achieve 1.0 ppm Bayluscide concentration according to the producer's instruction in Massachussett-USA.

Effect of precocene II, ecdysone and juvenile Hormone on the glicogen concentration in pupae of Stomocys calcitram (Diptera muscidae)

Third instar larvae of Stomoxys calcitrans (L.) were treated with precocene II, ecdysone and juvenile hormone. The larvae were allowed to develop until pupation and when it occurred, determination of glycogen levels was assayed. The administration of those three substances have interfered on the clycogen concentration. the precocene II causing a decrease whereas the ecdysone and juvenile hormone causing an increase. The ecdysone administered together withprecocene II reverses the effect of the latter. This does not happen when precocene II is administered together with the juvenile hormone. Ecdysone administered together with juvenilehormone causes reduction of the glycogen concentration.

Detection of Rotavirus in Sewage and Creek Water: Efficiency of the Concentration Method

Simian rotavirus SA-11, experimentally seeded, was recovered from raw domestic sewage by a two-step concentration procedure, using filtration through a positively charged microporous filter (Zeta Plus 60 S) followed by ultracentrifugation, effecting an 8,000-fold concentration. By this method, a mean recovery of 81% ± 7.5 of the SA-11 virus, was achieved

Factors that can interfere with virus concentration from wastewater when using zeta plus 60S filter membranes

Zeta plus filter membranes (ZP60S) have been shown to be efficient for rotavirus concentration from wastewater and for the reduction of cytotoxicity for cell cultures. Recently a variability in both properties was observed. In view of the low costs and the high virus recovery rates obtained in the past, we re-evaluated the application of ZP60S filter membranes for virus concentration from environmental samples. Some factors that could interfere with the concentration strategy using ZP60S were also considered and assessed including the type of water to be filtered and the possible release of toxic substances from the membrane matrix during filtration.

Slime production and proteinase activity of Candida species isolated from blood samples and the comparison of these activities with minimum inhibitory concentration values of antifungal agents

Slime and proteinase activity of 54 strains consisting of 19 Candida parapsilosis and 35 C. albicans strains isolated from blood samples were investigated in this study. Ketoconazole, amphothericin B, and fluconazole susceptibility of Candida species were compared with slime production and proteinase activity of these species. For both Candida species, no correlation was detected between the slime activity and minimum inhibitory concentration (MIC) values of the three antifungal agents. For both Candida species no correlation was detected between the proteinase activity and the MIC values of amphothericin B, and fluconazole however, statistically significant difference, was determined between the proteinase activity and MIC values of ketoconazole (p = 0.007). Slime production was determined by using modified Christensen macrotube method and proteinase activity was measured by the method of Staib. Antifungal susceptibility was determined through the guidelines of National Committee for Laboratory Standards (NCCLS M27-A).

Effect of CO2 and 1-octen-3-ol attractants for estimating species richness and the abundance of diurnal mosquitoes in the southeastern Atlantic forest, Brazil

Studies have shown that both carbon dioxide (CO2) and octenol (1-octen-3-ol) are effective attractants for mosquitoes. The objective of the present study was to evaluate the attractiveness of 1-octen-3-ol and CO2 for diurnal mosquitoes in the southeastern Atlantic forest. A Latin square experimental design was employed with four treatments: CDC-light trap (CDC-LT), CDC-LT and 1-octen-3-ol, CDC-LT and CO2 and CDC-LT with 1-octen-3-ol and CO2. Results demonstrated that both CDC-CO2 and CDC-CO2-1-octen-3-ol captured a greater number of mosquito species and specimens compared to CDC-1-octen-3-ol; CDC-LT was used as the control. Interestingly, Anopheles (Kerteszia) sp. was generally attracted to 1-octen-3-ol, whereas Aedes serratus was the most abundant species in all Latin square collections. This species was recently shown to be competent to transmit the yellow fever virus and may therefore play a role as a disease vector in rural areas of Brazil.

The efficiency of concentration methods used to detect enteric viruses in anaerobically digested sludge

The presence of enteric viruses in biosolids can be underestimated due to the inefficient methods (mainly molecular methods) used to recover the viruses from these matrices. Therefore, the goal of this study was to evaluate the different methods used to recover adenoviruses (AdV), rotavirus species A (RVA), norovirus genogroup II (NoV GII) and the hepatitis A virus (HAV) from biosolid samples at a large urban wastewater treatment plant in Brazil after they had been treated by mesophilic anaerobic digestion. Quantitative polymerase chain reaction (PCR) was used for spiking experiments to compare the detection limits of feasible methods, such as beef extract elution and ultracentrifugation. Tests were performed to detect the inhibition levels and the bacteriophage PP7 was used as an internal control. The results showed that the inhibitors affected the efficiency of the PCR reaction and that beef extract elution is a suitable method for detecting enteric viruses, mainly AdV from biosolid samples. All of the viral groups were detected in the biosolid samples: AdV (90%), RVA, NoV GII (45%) and HAV (18%), indicating the viruses' resistance to the anaerobic treatment process. This is the first study in Brazil to detect the presence of RVA, AdV, NoV GII and HAV in anaerobically digested sludge, highlighting the importance of adequate waste management.

The impact of CO2 on collection of Aedes aegypti (Linnaeus) and Culex quinquefasciatus Say by BG-Sentinel(r) traps in Manaus, Brazil

Carbon dioxide (CO2) is an important component for activating and attracting host-seeking mosquitoes. The BG-Sentinel(r) trap is a well-established monitoring tool for capturing Culicidae, but CO2 role for the trap effectiveness has not been evaluated in highly urbanised areas. The objective was to evaluate the effectiveness of BG-Sentinel traps baited with and without CO2 for capturing urban mosquitoes. Fifteen areas were selected within the city of Manaus, Brazil, where four BG-Sentinels were operated for 24 h, two of them with CO2 and two without CO2. Captured Aedes aegypti females were dissected for the determination of their parity status. A significantly higher proportion of traps (from 32-79%) were positive for female Ae. aegypti when using the BG-Sentinel with CO2 (χ2 = 11.0271, p ≤ 0.001). Catches of female Culex spp were six times higher in CO2 traps (Mann-Whitney U test = 190.5; p = 0.001). Parity rates were similar for both traps. This study showed that CO2 has primarily an enhancing effect on the efficacy of BG-Sentinel for capturing Culex spp in Manaus. For Ae. aegypti, the positivity rate of the trap was increased, when CO2 was added.

Influence of age on the haemoglobin concentration of malaria-infected patients in a reference centre in the Brazilian Amazon

Anaemia is amongst the major complications of malaria, a major public health problem in the Amazon Region in Latin America. We examined the haemoglobin (Hb) concentrations of malaria-infected patients and compared it to that of malaria-negative febrile patients and afebrile controls. The haematological parameters of febrile patients who had a thick-blood-smear performed at an infectious diseases reference centre of the Brazilian Amazon between December 2009-January 2012 were retrieved together with clinical data. An afebrile community control group was composed from a survey performed in a malaria-endemic area. Hb concentrations and anaemia prevalence were analysed according to clinical-epidemiological status and demographic characteristics. In total, 7,831 observations were included. Patients with Plasmodium falciparum infection had lower mean Hb concentrations (10.5 g/dL) followed by P. vivax-infected individuals (12.4 g/dL), community controls (12.8 g/dL) and malaria-negative febrile patients (13.1 g/dL) (p < 0.001). Age, gender and clinical-epidemiological status were strong independent predictors for both outcomes. Amongst malaria-infected individuals, women in the reproductive age had considerably lower Hb concentrations. In this moderate transmission intensity setting, both vivax and falciparum malaria are associated with reduced Hb concentrations and risk of anaemia throughout a wide age range.

Dynamics of the control of Aedes (Stegomyia) aegypti Linnaeus (Diptera, Culicidae) by Bacillus thuringiensis var israelensis, related with temperature, density and concentration of insecticide

The dynamics of the control of Aedes (Stegomyia) aegypti Linnaeus, (Diptera, Culicidae) by Bacillus thuringiensis var israelensis has been related with the temperature, density and concentration of the insecticide. A mathematical model for biological control of Aedes aegypti with Bacillus thuringiensis var israelensis (Bti) was constructed by using data from the literature regarding the biology of the vector. The life cycle was described by differential equations. Lethal concentrations (LC50 and LC95) of Bti were determined in the laboratory under different experimental conditions. Temperature, colony, larvae density and bioinsecticide concentration presented marked differences in the analysis of the whole set of variables; although when analyzed individually, only the temperature and concentration showed changes. The simulations indicated an inverse relationship between temperature and mosquito population, nonetheless, faster growth of populations is reached at higher temperatures. As conclusion, the model suggests the use of integrated control strategies for immature and adult mosquitoes in order to achieve a reduction of Aedes aegypti.

Biomassa microbiana e produção de C-CO2 e N mineral de um podzólico vermelho-escuro submetido a diferentes sistemas de manejo: Microbial biomass and C-CO2 and mineral nitrogen production in paleudult soil cultivated under different management systems

Os sistemas de manejo, com diferenças no revolvimento do solo e na composição dos resíduos vegetais, alteram as propriedades biológicas do solo, com reflexos na qualidade do solo e na produtividade das culturas. Com vistas em medir estas alterações nas propriedades biológicas do solo, a biomassa e a atividade microbiana foram avaliadas em um Podzólico Vermelho-Escuro, em Eldorado do Sul (RS), utilizando diferentes preparos (convencional, reduzido e plantio direto) e dois sistemas de sucessões de culturas (aveia preta + vica/milho + caupi e aveia/milho). As avaliações foram realizadas em quatro épocas, durante 12 meses, e em duas profundidades (0-5 e 5-15 cm). O carbono da biomassa microbiana foi analisado pelo método de fumigação-incubação, e a atividade microbiana, pela produção de C-CO2 e N mineral, após 60 dias de incubação. As diferenças na biomassa e na atividade microbiana, entre os sistemas de manejo, foram mais pronunciadas na camada de 0-5 cm. Nesta camada de solo, observaram-se os maiores valores de biomassa e de atividade nos preparos conservacionistas e no sistema aveia + vica/milho + caupi. Dentre as variáveis estudadas, a mineralização de N mostrou-se a mais sensível aos manejos, à profundidade e à época de amostragem.

Efeito de sistemas de preparo e de cultura na dinâmica da matéria orgânica e na mitigação das emissões de CO2

Neste estudo, ajustou-se um modelo exponencial de primeira ordem aos dados de carbono orgânico (CO) e N total (NT) do solo, do 5º e 9º ano de um experimento instalado em um Podzólico Vermelho-Escuro, em Eldorado do Sul (RS). Determinaram-se os parâmetros da dinâmica da matéria orgânica e simularam-se os estoques de CO e NT do solo em três sistemas de preparo (convencional-PC, reduzido-PR e plantio direto-PD) e três sistemas de cultura (aveia/milho-A/M, aveia + ervilhaca/milho-A + E/M e aveia + ervilhaca/milho + caupi A + E/M + C). A taxa de decomposição da matéria orgânica do solo diminuiu de 0,054 ano-1, no sistema com lavração e gradagem (PC), para 0,039 ano-1, no solo escarificado (PR), e 0,029 ano-1, no solo não revolvido (PD). Estimou-se que os estoques de CO e NT do solo em 1990 (30,78 Mg ha-1 e 2.200 kg ha-1) diminuirão para 16,11 Mg ha-1 e 1.396 kg ha-1 na combinação PC - A/M. Por sua vez, no sistema PD - A + E/M + C, os estoques de CO e NT do solo em 1990 (32,52 Mg ha-1 e 2.690 Mg ha-1) tenderão a aumentar a estoques estáveis de 54,83 Mg ha-1 e 7.966 kg ha-1, respectivamente. Os sistemas de manejo sem revolvimento do solo e alto aporte de resíduos apresentaram efeito positivo na mitigação das emissões de CO2. Enquanto o sistema PC-A/M apresentou um efluxo líquido (emitido pelo solo > fixado pelas culturas por fotossíntese) de 2,08 Mg CO2 ha-1 para atmosfera no ano de 1994, o sistema PD - A + E/M + C mostrou um influxo líquido (emitido pelo solo < fixado pelas culturas) de CO2 de 1,79 Mg ha-1 ano-1. Atingidos os estoques estáveis de CO no solo estimados pelo modelo, o solo no sistema PD - A + E/M + C terá seqüestrado aproximadamente 142 Mg CO2 ha-1, em comparação ao sistema PC-A/M.

Extraction and concentration of biogenic calcium oxalate from plant leaves

The objective of this study was to extract and concentrate calcium oxalate (CaOx) crystals from plant leaves that form the above mentioned crystals. The chemical and physical studies of CaOx from plant to be performed depend on an adequate amount of the crystals. The plant used in this study was croton (Codiaeum variegatum). The leaves were ground in a heavy duty blender and sieved through a 0.20 mm sieve. The suspension obtained was suspended in distilled water. The crystals were concentrated at the bottom of a test tube. The supernatant must be washed until it is free of plant pigments and other organic substances. Biogenic CaOx crystals have well-defined and sharp peaks, indicating very high crystallinity. Moreover, the CaOx crystals were not damaged during the extraction procedure, as can be seen on the scanning electron microscope images. The porposed method can be considered efficient to extract and concentrate biogenic calcium oxalate.

Rotação de culturas no sistema plantio direto em Tibagi (PR): II - Emissões de CO2 e N2O

A atividade agrícola pode alterar a quantidade e qualidade da matéria orgânica do solo (MOS), resultando em emissões de dióxido de carbono (CO2) e óxido nitroso (N2O) do solo para a atmosfera. O sistema plantio direto (SPD) com a utilização de leguminosas em sistemas de rotação é uma estratégia que deve ser considerada tanto para o aumento da quantidade de MOS como para seu efeito na redução das emissões dos gases de efeito estufa. Com o objetivo de determinar os fluxos de gases do efeito estufa (CO2 e N2O) do solo, um experimento foi instalado em Tibagi (PR), em um Latossolo Vermelho distroférrico textura argilosa. Os tratamentos, dispostos em faixas não casualizadas com parcelas subdivididas, foram: sistema plantio direto por 12 anos com sucessões milho/trigo e soja/trigo (PD12 M/T e PD12 S/T, respectivamente) e por 22 anos (PD22 M/T e PD22 S/T, respectivamente). As emissões de CO2 do solo foram aproximadamente 20 % mais elevadas no PD22 em relação ao PD12. As emissões de CO2 apresentaram correlação significativa (R² = 0,85; p < 0,05) com a temperatura do solo, com emissões médias 40 % menores, registradas nos meses com temperaturas mais baixas. As emissões mais elevadas de N2O foram observadas após a colheita das culturas de verão, sobretudo na sucessão milho/trigo, em relação à sucessão soja/trigo. As emissões de N2O foram aproximadamente 25 % maiores após aplicação do fertilizante nitrogenado na cultura do trigo nas duas sucessões e apresentaram correlação significativa (R² = 0,88; p < 0,01) com o grau de saturação de água no solo (Sr %).

CO2, CH4 and N2O fluxes in an Ultisol treated with sewage sludge and cultivated with castor bean

Organic residue application into soil alter the emission of gases to atmosphere and CO2, CH4, N2O may contribute to increase the greenhouse effect. This experiment was carried out in a restoration area on a dystrophic Ultisol (PVAd) to quantify greenhouse gas (GHG) emissions from soil under castor bean cultivation, treated with sewage sludge (SS) or mineral fertilizer. The following treatments were tested: control without N; FertMin = mineral fertilizer; SS5 = 5 t ha-1 SS (37.5 kg ha-1 N); SS10 = 10 t ha-1 SS (75 kg ha-1 N); and SS20 = 20 t ha-1 SS (150 kg ha-1 N). The amount of sludge was based on the recommended rate of N for castor bean (75 kg ha-1), the N level of SS and the mineralization fraction of N from SS. Soil gas emission was measured for 21 days. Sewage sludge and mineral fertilizers altered the CO2, CH4 and N2O fluxes. Soil moisture had no effect on GHG emissions and the gas fluxes was statistically equivalent after the application of FertMin and of 5 t ha-1 SS. The application of the entire crop N requirement in the form of SS practically doubled the Global Warming Potential (GWP) and the C equivalent emissions in comparison with FertMin treatments.