Serological, electrophoretic and biological properties of Fasciola hepatica antigens

Fasciola hepatica somatic antigen, its partially purified fractions and excretion-secretion products were investigated as to serological, electrophoretic and biological properties. In a Sephadex G-100 column (SG-100), Fasciola hepatica total antigen (FhTA) gave 5 fractions, and SDS-PAGE analysis showed they were glycoproteins ranging from 14 to 94 kDa molecular weight (MW). When these fractions were analyzed by enzyme linked immunotransfer blot (EITB) and immunodiffusion in gel (ID) with serum from immunized rats with FhTA, the presence of different antigenic components was revealed. In the SDS-PAGE of excretor-secretor antigen (ESA), it was possible to observe peptides from 12 to 22 kDa, which were also present in FhTA. When the FhTA, its fractions and the ESA were analyzed by EITB with the immune rat serum (IRS), it was observed that only some fractions of the SG-100 shared antigens with the FhTA and ESA. Moreover, DTH and ITH responses were studied in FhTA immunized rats challenged with these different antigen components, revealing that the protein/carbohydrate ratio is important for inducing DTH response. The ESA was the most active component in the DTH and ITH response.

Some biological properties of the human amniotic membrane interferon

Human amniotic interferon was investigated to define the species specificity of its antiviral action and compare its anti-cellular and NK cell stimulating activities with those of other human interferons. The antiviral effect was titrated in bovine (RV-IAL) and monkey (VERO) cells. Amniotic interferon exhibited, in bovine cells, 5% of the activity seen in monkey cells, while alpha interferon displayed 200%. No effect was detected with either beta or gamma interferon in bovine cells. Daudi cells were exposed to different concentrations of various interferons and the cell numbers were determined. The anticellular effect of the amniotic interferon reached its peak on the third day of incubation. Results suggested a higher activity for alpha and gamma interferons and a lower activity for beta when compared to amniotic interferon. Using total mononuclear cells as effector cells and K 562 as target cell in a 51Cr release assay, it was demonstrated that low concentrations of amniotic interferon consistently stimulated NK cell activity in cells derived from several donors, the results indicating a higher level of activity with this interferon than with alpha and beta interferons.

Spatial variability of the chemical, physical and biological properties in lowland cultivated with irrigated rice

In the areas where irrigated rice is grown in the south of Brazil, few studies have been carried out to investigate the spatial variability structure of soil properties and to establish new forms of soil management as well as determine soil corrective and fertilizer applications. In this sense, this study had the objective of evaluating the spatial variability of chemical, physical and biological soil properties in a lowland area under irrigated rice cultivation in the conventional till system. For this purpose, a 10 x 10 m grid of 100 points was established, in an experimental field of the Embrapa Clima Temperado, in the County of Capão do Leão, State of Rio Grande do Sul. The spatial variability structure was evaluated by geostatistical tools and the number of subsamples required to represent each soil property in future studies was calculated using classical statistics. Results showed that the spatial variability structure of sand, silt, SMP index, cation exchange capacity (pH 7.0), Al3+ and total N properties could be detected by geostatistical analysis. A pure nugget effect was observed for the nutrients K, S and B, as well as macroporosity, mean weighted diameter of aggregates, and soil water storage. The cross validation procedure, based on linear regression and the determination coefficient, was more efficient to evaluate the quality of the adjusted mathematical model than the degree of spatial dependence. It was also concluded that the combination of classical with geostatistics can in many cases simplify the soil sampling process without losing information quality.

Chemical and biological properties of phosphorus-fertilized soil under legume and grass cover (Cerrado region, Brazil)

The use of cover crops has been suggested as an effective method to maintain and/or increase the organic matter content, while maintaining and/or enhancing the soil physical, chemical and biological properties. The fertility of Cerrado soils is low and, consequently, phosphorus levels as well. Phosphorus is required at every metabolic stage of the plant, as it plays a role in the processes of protein and energy synthesis and influences the photosynthetic process. This study evaluated the influence of cover crops and phosphorus rates on soil chemical and biological properties after two consecutive years of common bean. The study analyzed an Oxisol in Selvíria (Mato Grosso do Sul, Brazil), in a randomized block, split plot design, in a total of 24 treatments with three replications. The plot treatments consisted of cover crops (millet, pigeon pea, crotalaria, velvet bean, millet + pigeon pea, millet + crotalaria, and millet + velvet bean) and one plot was left fallow. The subplots were represented by phosphorus rates applied as monoammonium phosphate (0, 60 and 90 kg ha-1 P2O5). In August 2011, the soil chemical properties were evaluated (pH, organic matter, phosphorus, potential acidity, cation exchange capacity, and base saturation) as well as biological variables (carbon of released CO2, microbial carbon, metabolic quotient and microbial quotient). After two years of cover crops in rotation with common bean, the cover crop biomass had not altered the soil chemical properties and barely influenced the microbial activity. The biomass production of millet and crotalaria (monoculture or intercropped) was highest. The biological variables were sensitive and responded to increasing phosphorus rates with increases in microbial carbon and reduction of the metabolic quotient.

Biological aspects of the DM28C clone of Trypanosoma cruzi after metacylogenesis in chemically defined media

The biological characterization of the Trypanosoma cruzi clone Dm 28c in terms of its growth in LIT medium, cell-cycle, infectivity to mice and interaction with professional and non-professional phagocytic cells shows that it behaves as a bona fide T. cruzi representant. The biological properties of this myotropic clone do not change according to the origin of the trypomastigote forms (i. e., from triatomines, infected mice, cell-culture or from the chemically defined TAUP and TAU3AAG media). In addition Dm 28c metacyclic trypomastigotes from TAU3AAG medium display a high infectivity level to fibroblasts and muscle cells. Experiments on binding of cationized ferritin to trypomastigotes surface show the existence of cap-like structures of ferritin in regions near the kinetoplast. However the nature and role of these anionic sites remain to be determined. The results indicate that metacyclic trypomastigotes from Dm 28c clone obtained under chemically defined conditions reproduce the biological behaviour of T. cruzi, rendering this system very suitable for the study of cell-parasite interactions and for the isolation of trypanosome relevant macromolecules.

Biological characterization of Trypanosoma cruzi strains from different zymodemes and schizodemes

The development in C3H mice of thirteen strains of Trypanosoma cruzi belonging to different zymodemes ans schizodemes was studied. Host mortality, virulence, histiotropism, parasitemia and polymorphism of the parasites were recorded. The strains were grouped into: a) high virulence - causing 100% mortality and characterized by predominance of bery broad trypomastigotes in the bloodstream at the end of infection; b) medium virulence - causing no mortality and with a predominance of broad trypomastigotes; c) low virulence - causing no mortality with blood forms not described due to the very low parasitemia. During 18 months maintenance the parasitemia curves were kept constant for all strains except one. A direct correlation between either zymodeme or schizodeme and experimental biological properties of T. cruzi strains was not found. However, the parasitemia was subpatent and patent for strains from zymodeme C and the others respectively. Furthermore the high virulence seems to be related to one of two shizodemes found within zymodeme B strains. All strains presenting patent parasitemia independent of shizodeme and ymodeme showed a myotropism towards heart and skeletal muscle with varible inflammatory intensity. The present study confirmed the heterogeneity found by isoenzyme and K-DNA patterns among the strains of T. cruzi isolated from chagasic patients in Bambuí, Minas Gerais State, Brasil.

Molecular and biological diversity of HIV-1 in Brazil

To determine the genomic polymorphism and biological properties present in HIV-1 Brazilian isolates, were analyzed five viral isolates obtained from patients residing in Rio de Janeiro (P1 and P5), São Paulo (P3) and Bahia (P2 and P4) states. For each viral isolate in vitro characteristics such as replication rate, syncytium-inducing capacity and cell death were observed in lymphoblastoid (H9, CEM and peripheral blood mononuclear cells) as well as monocytoid (U937) cells. In addition, the evaluation of the restriction fragment lenght polymorphism of these isolates was also performed using a panel of endonucleases such as Hind III, Bgl II, Sac I, Pst I, Kpn I and Eco RI. One of the isolates (P1), showed the highest phenotypic and genotypic divergence, when compared to others. The results found suggest a HIV heterogeneity in Brazil similar to that already described in other regions of the world.

Trypanosoma cruzi: metacyclogenesis in vitro - I. Changes in the properties of metacyclic trypomastigotes maintained in the laboratory by different methods

In this work we have studied the modifications in the biological properties of Trypanosoma cruzi when the parasite is maintained for a long time in axenic culture. The studies were done with a clone from an avirulent strain (Dm30L) and a non-cloned virulent strain (EP) of T. cruzi. Both parasiteswere maintained, for at least three years, by successive triatomine/mouse alternate passage (control condition), or by serial passage in axenic medium (culture condition), or only in the mouse (mouse condition). The comparison between parasites of culture and control condition showed that metacyclogenesis capacity was reduced in the former and that the resulting metacyclics displayed an attenuatedvirulence. In order to compare the virulence of metacyclics from the urine of the insect vector, Rhodnius prolixus were infected by artificial feeding with parasites of the control or culture condition. After three triatomine/triatomine passages, there was observed an almost identical biological behavior for these parasites, hence indicating that the maintenance of T. cruzi for a long time in axenic culture affects the differentiation capacity and the virulence of the parasite. Additionally, it was demonstrated that it is possible to maintain T. cruzi exclusively through passages in the invertebrate host.

Biological comparison between three clones of Trypanosoma cruzi and the strain of origin (Bolivia) with reference to clonal evolution studies

After isolating three clones of Trypanasoma cruzi (Bolivia), we first characterized them according to parasitaemia, pleomorphism and virulence, and then histopathologically. The study's interest lies on the hypothesis that clonal evolution of T. cruzi has a major impact on biologically relevant properties of this parasite. Data obtained from the studies of parasitaemia, pleomorphism and virulence showed no differences between the groups studied. As a final point, the histopathological study shows us a muscular tissue tropism both in clones and in their mother strain (Bolivia). In this paper, we conclude that Bolivia strain and clones isolated from it, pertaining to the same major clone share similar biological properties.

Microbial biomass and soil chemical properties under different land use systems in northeastern Pará

The increase in agricultural production in the Brazilian Amazon region is mostly a result of the agricultural frontier expansion, into areas previously influenced by humans or of native vegetation. At the same time, burning is still used to clear areas in small-scale agricultural systems, leading to a loss of the soil productive capacity shortly after, forcing the opening of new areas. This study had the objective of evaluating the effect of soil preparation methods that involve plant residue shredding, left on the surface or incorporated to the soil, with or without chemical fertilization, on the soil chemical and biological properties. The experiment was conducted in 1995, in an experimental field of Yellow Latosol (Oxisol) of the Embrapa Amazônia Oriental, northeastern Pará (Brazil). The experiment was arranged in randomized blocks, in a 2x6 factorial design, with two management systems and six treatments evaluated twice. The management systems consisted of rice (Oriza sativa), followed by cowpea (Vigna unguiculata) with manioc (Manihot esculenta). In the first system the crops were planted in two consecutive cycles, followed by a three-year fallow period (natural regrowth); the second system consisted of one cultivation cycle and was left fallow for three years. The following treatments were applied to the secondary forest vegetation: slash and burn, fertilized with NPK (Q+NPK); slash and burn, without fertilizer NPK (Q-NPK); cutting and shredding, leaving the residues on the soil surface, fertilized with NPK (C+NPK); cutting and shredding, leaving residues on the soil surface, without fertilizer (C-NPK); cutting and shredding, with residue incorporation and fertilized with NPK (I+NPK); cutting and shredding, with residue incorporation and without NPK fertilizer (I-NPK). The soil was sampled in the rainier season (April 2006) and in the drier season (September 2006), in the 0-0.1 m layer. From each plot, 10 simple samples were collected in order to generate a composite sample. In the more intensive management system the contents of microbial C (Cmic) and microbial N (Nmic) were higher, while the C (Corg) level was higher in the less intensive system. The treatments with highest Cmic and Nmic levels were those with cutting, shredding and distribution of biomass on the soil surface. Under both management systems, the chemical characteristics were in ranges that classify the soil as little fertile, although P and K (in the rainy season) were higher in the less intensive management system.

Chemical and biochemical properties of Araucaria angustifolia (Bert.) Ktze. forest soils in the state of São Paulo

Araucaria angustifolia, commonly named Araucaria, is a Brazilian native species that is intensively exploited due to its timber quality. Therefore, Araucaria is on the list of species threatened by extinction. Despite the importance of soil for forest production, little is known about the soil properties of the highly fragmented Araucaria forests. This study was designed to investigate the use of chemical and biological properties as indicators of conservation and anthropogenic disturbance of Araucaria forests in different sampling periods. The research was carried out in two State parks of São Paulo: Parque Estadual Turístico do Alto do Ribeira and Parque Estadual de Campos de Jordão. The biochemical properties carbon and nitrogen in microbial biomass (MB-C and MB-N), basal respiration (BR), the metabolic quotient (qCO2) and the following enzyme activities: β-glucosidase, urease, and fluorescein diacetate hydrolysis (FDA) were evaluated. The sampling period (dry or rainy season) influenced the results of mainly MB-C, MB-N, BR, and qCO2. The chemical and biochemical properties, except K content, were sensitive indicators of differences in the conservation and anthropogenic disturbance stages of Araucaria forests. Although these forests differ in biochemical and chemical properties, they are efficient in energy use and conservation, which is shown by their low qCO2, suggesting an advanced stage of succession.

Soil biological attributes in pastures of different ages in a crop-livestock integrated system

The objective of this work was to evaluate the effect of the pasture (Urochloa brizantha) component age on soil biological properties, in a crop-livestock integrated system. The experiment was carried out in a Brazilian savannah (Cerrado) area with 92 ha, divided into six pens of approximately 15 ha. Each pen represented a different stage of the pasture component: formation, P0; one year, P1; two years, P2; three years, P3; and final with 3.5 years, Pf. Samples were taken in the 0-10 cm soil depth. The soil biological parameters - microbial biomass carbon (MBC), microbial biomass respiration (C-CO2), metabolic quotient (qCO2), microbial quotient (q mic), and total organic carbon (TOC) - were evaluated and compared among different stages of the pasture, and between an adjacent area under native Cerrado and another area under degraded pasture (PCD). The MBC, q mic and TOC increased and qCO2 reduced under the different pasture stages. Compared to PCD, the pasture stages had higher MBC, q mic and TOC, and lower qCO2. The crop-livestock integrated system improved soil microbiological parameters and immobilized carbon in the soil in comparison to the degraded pasture.

Biological activity of Serratia marcescens cytotoxin

Serratia marcescens cytotoxin was purified to homogeneity by ion-exchange chromatography on a DEAE Sepharose Fast Flow column, followed by gel filtration chromatography on a Sephadex G100 column. The molecular mass of the cytotoxin was estimated to be about 50 kDa. Some biological properties of the cytotoxin were analyzed and compared with well-characterized toxins, such as VT1, VT2 and CNF from Escherichia coli and hemolysin produced by S. marcescens. The sensitivity of the cell lines CHO, HeLa, HEp-2, Vero, BHK-21, MA 104 and J774 to the cytotoxin was determined by the cell viability assay using neutral red. CHO and HEp-2 were highly sensitive, with massive cellular death after 1 h of treatment, followed by BHK-21, HeLa, Vero and J774 cells, while MA 104 was insensitive to the toxin. Cytotoxin induced morphological changes such as cell rounding with cytoplasmic retraction and nuclear compactation which were evident 15 min after the addition of cytotoxin. The cytotoxic assays show that 15 min of treatment with the cytotoxin induced irreversible intoxication of the cells, determined by loss of cell viability. Concentrations of 2 CD50 (0.56 µg/ml) of purified cytotoxin did not present any hemolytic activity, showing that the cytotoxin is distinct from S. marcescens hemolysin. Antisera prepared against S. marcescens cytotoxin did not neutralize the cytotoxic activity of VT1, VT2 or CNF toxin, indicating that these toxins do not share antigenic determinants with cytotoxin. Moreover, we did not detect gene sequences for any of these toxins in S. marcescens by PCR assay. These results suggest that S. marcescens cytotoxin is not related to any of these toxins from E. coli.

Yield and nutrition of sunflower fertilized with sewage sludge stabilized by different processes

The different methods of sewage sludge stabilization modify their physical chemical and biological properties, altering its efficiency when applied in agriculture. The objective of this study was to evaluate the nutrient levels in soil and the yield of sunflower fertilized with sewage sludge stabilized by different processes. The experiment was conducted in Cambisol, with the treatments: control (without fertilization), fertilization with sewage sludge solarized, composted, vermicomposted, limed and chemical fertilizer recommended for sunflower crop. The experimental design a randomized block with four replications. The different methods of sewage sludge treatment did not affect the yield; however, the application of sewage sludge, regardless the stabilization process adopted, was more effective than chemical fertilizer and the control treatment. Overall, fertilization with limed sewage sludge provided higher soil nutrients concentrations, while treatments with composted and vermicomposted sewage sludge showed higher levels of nutrients in the plant.

The "in vitro" antifungal activity evaluation of propolis G12 ethanol extract on Cryptococcus neoformans

Cryptococcosis is a worldwide disease caused by the etiological agent Cryptococcus neoformans. It affects mainly immunocompromised humans. It is relatively rare in animals only affecting those that have received prolonged antibiotic therapy. The propolis is a resin that can present several biological properties, including antibacterial, antifungal and antiviral activities. The standard strain C. neoformans ATTC 90112 was used to the antifungal evaluation. The tests were realized with propolis ethanol extract (PEE) G12 in concentrations from 0.1 to 1.6 mg mL-1. The evaluation of MIC and MFC were done according to DUARTE (2002)5. The inhibitory effect of PEE G12 on the fungal growing was seen at the concentration of 0.2 mg mL-1 and 1.6 mg mL-1 was considered a fungicidal one.