Influence of paclobutrazol on water consumption and plant performance of Arbutus unedo seedlings

The purpose of this study was to examine the effect of paclobutrazol on the water consumption, plant water relations, gas exchange and development of strawberry tree seedlings (Arbutus unedo L.), to evaluate water resource management. Seedlings (8 cm in height) were subjected to a single drench of 60 or 100 mg of paclobutrazol and pot-grown in a greenhouse for 4 months. Untreated plants acted as control. Paclobutrazol reduced the development and improved the water status of the seedlings. At the end of the experimental period, it was seen that the two doses studied had reduced the plant dry weight, plant height and foliar development compared with the untreated plants. Paclobutrazol significantly reduced water consumption by 10% (60 mg) and 20% (100 mg) compared with the control. Plants treated with 100 mg showed the highest leaf water potential values at predawn. Paclobutrazol-treated plants presented turgor potential at values midday higher than control. This retardant stimulated a more efficient stomatal regulation, permitted an improved water status; however, it altered photosynthesis, reducing the plant growth. The lowered water consumption in paclobutrazol-treated plants was the result of a combination of mechanisms which reduced water loss through transpiration.     

High prevalence of Blastocystis sp. in pigs reared under intensive growing systems: frequency of ribotypes and associated risk factors

Three hundred and ninety-five pig fecal samples were analyzed looking for Blastocystis sp. using optical microscopy and PCR. A global prevalence of 46.8% has been observed in this study, although relative values of prevalence differ notably according to the strata examined, ranging from 9.3% in sows to 75% in weaners. Statistic analysis of the data included several risk factors such as different management systems, date of sample collection, fecal consistency, age and sex of the animals. The presence of the parasite was statistically associated to the variables "age" and "date of sample collection", being more prevalent in weaners and grower pigs and warm season. Random fragment-length polymorphism (RFLP-PCR) analysis of positive PCR samples revealed a high homology in the digestion pattern, appearing as two ribotypes. The results were further confirmed by sequencing of ten randomly selected samples, showing that the samples obtained in this study were included in two genotypes: genotype I previously named by No?l et al. [No?l, C., Dufernez, F., Gerbod, D., Edgcomb, V.P., Delgado-Viscogliosi, P., Ho, L.-Ch., Singh, M., Wintjens, R., Sogin, M.L., Capron, M., Pierce, R., Zenner, L., Viscogliosi, E., 2005. Molecular phylogenies of Blastocystis isolates from different hosts: implications for genetic diversity, identification of species, and zoonosis. J. Clin. Microbiol. 43, 348-355], in which Blastocystis sp. sequences from humans, pigs and cattle were included, and genotype II, which only included Blastocystis hominis sequences obtained from human and other primates. This is the first report including Blastocystis sequences from swine origin in genotype II.     

Evaluation of IFA, MAT, ELISAs and immunoblotting for the detection of anti-Toxoplasma gondii antibodies in paired serum and aqueous humour samples from experimentally infected pigs

The study evaluated the efficiency of diagnostic laboratory methods to detect anti-Toxoplasma gondii antibodies in paired serum and aqueous humour samples from experimentally infected pigs. 18-mixed breed pigs were used during the experiment; these were divided into two groups, G1 (infected group, n=10) and G2 (uninfected group, n=8). Infection was performed with 4 x 10(4) VEG strain oocysts at day 0 by the oral route in G1 animals. All pigs were euthanized at day 60, when retina, aqueous humour, and blood samples were collected. Anti-T. gondii antibody levels were assessed in serum (s) and aqueous humour (ah) by indirect immunofluorescence assay (IFA), modified agglutination test (MAT), m-ELISA (using crude membranes from T. gondii tachyzoites as antigen) and r-ELISA (using rhoptries from T. gondii tachyzoites as antigen). Polymerase chain reactions (PCR) of samples from the retina were performed by using Tox4 and Tox5 primers. Antibody titers of G1 animals ranged from 128 to 1024 and from 16 to 256 in serum and aqueous humour, respectively. There were differences in the correlation coefficients between IFA(s) x IFA (ah) (r=0.62, P=0.05), MAT(s) x MAT (ah) (r=0.97, P<0.0001); however, there was no significant difference between r-ELISA(s) x r-ELISA (ah) (r= 0.14, P=0.7). Antibodies present in serum and aqueous humour recognized similar antigens. Samples of retina were positive by PCR in 30% (3/10) of infected pigs. G2 animals remained without antibody levels and were PCR negative throughout the experiment. These results suggest that the use of a combination of tests and immunoblotting for paired aqueous humour and serum samples could improve the sensitivity and specificity for the diagnosis of ocular toxoplasmosis.     

Biological characterization of citrus tristeza virus isolates by in vitro tissue cultures

Stem segments from Mexican lime, sweet orange, grapefruit, Citrus excelsa and alemow, infected with five citrus tristeza virus (CTV) isolates, were cultured in vitro . Regeneration of roots and shoots were modified as a result of infection. The effect of CTV on the morphogenesis of stem segments cultured in vitro depended on the CTV isolate and the plant host, and showed a correlation with the in vivo effects observed in biological indexing. Evaluation of the morphogenic response of stem segments of Mexican lime and grapefruit can be used as an additional tool for the biological characterization of CTV isolates. The symptoms on sweet orange plants obtained from regenerated shoots indicated that CTV is unevenly distributed in the host plant cells and that the regeneration process may be utilized as a tool to separate strains from complex field isolates.     

Structures and characteristics of carbohydrates in diets fed to pigs: a review

The current paper reviews the content and variation of fiber fractions in feed ingredients commonly used in swine diets. Carbohydrates serve as the main source of energy in diets fed to pigs. Carbohydrates may be classified according to their degree of polymerization: monosaccharides, disaccharides, oligosaccharides, and polysaccharides.Digestible carbohydrates include sugars, digestible starch, and glycogen that may be digested by enzymes secreted in the gastrointestinal tract of the pig. Non-digestible carbohydrates, also known as fiber, may be fermented by microbial populations along the gastrointestinal tract to synthesize short-chain fatty acids that may be absorbed and metabolized by the pig. These non-digestible carbohydrates include two disaccharides, oligosaccharides,resistant starch, and non-starch polysaccharides. The concentration and structure of non-digestible carbohydrates in diets fed to pigs depend on the type of feed ingredients that are included in the mixed diet. Cellulose,arabinoxylans, and mixed linked β-(1,3)(1,4)-D-glucans are the main cell wall polysaccharides in cereal grains, but vary in proportion and structure depending on the grain and tissue within the grain. Cell walls of oilseeds, oilseed meals, and pulse crops contain cellulose, pectic polysaccharides, lignin, and xyloglucans. Pulse crops and legumes also contain significant quantities of galacto-oligosaccharides including raffinose, stachyose, and verbascose. Overall,understanding the structure, characteristics and measurable chemical properties of fiber in feed ingredients may result in more accurate diet formulations, resulting in an improvement in the utilization of energy from less expensive high-fiber ingredients and a reduction in reliance on energy from more costly cereal grains.     

Disappearance of carbosulfan residues in peaches

The disappearance kinetics of the carbamate insecticide, carbosulfan, applied at 2 kg AI ha^?1 (‘Marshal’ 250 g litre^?1 EC) in peaches was studied. Degradation took place in two consecutive stages (0–28 and 28–57 days), with half-lives of 7.4 and 17.5 days, respectively. The residues obtained 57 days after treatment did not exceed 0.2 mg kg^?1. When treatments were carried out 30, 21 and 14 days before the probable date of harvest (date of fruit maturation) with two doses (1.0 and 2.0 g formulated product litre^?1) and two volumes applied (750 and 1500 litre ha^?1), the residual levels detected were between 0.122 mg kg^?1 (30 days before harvest) and 0.4 mg kg^?1 (14 days before harvest). The major metabolite, carbofuran, was never detected above its determination limit of 0.004 mg kg^?1 throughout the whole study.     

Development of the carob moth,Spectrobates ceratoniae,on stored almonds

Phytoparasitica - The life cycle of the carob moth,Spectrobates (= Ectomyelois) ceratoniae (Zeller), was examined on stored almonds held at 26±1°C and 70±5% relative humidity....     

Coefficients for the estimation of fresh weight and volume of Greater Rhea eggs

1. Specific values of constants needed to estimate fresh weight (Kw) and volume (Kv) of Greater Rhea eggs were obtained. 2. The average value for the weight coefficient (Kw) was 0.57, whereas that for volume (Kv) was 0.51. Accuracy of results obtained with these values was +/-2.1% and +/-3.5%, respectively. 3. The fresh weight and volume of Greater Rhea eggs can be easily estimated by means of these specific coefficients when those measurements cannot be taken directly.     

Prevalence of Neospora caninum and Toxoplasma gondii in sheep and dogs from Guarapuava farms, Paraná State, Brazil

Sheep and dog blood samples were collected from nine farms in the county of Guarapuava, Paraná, Brazil. The indirect fluorescent antibody test (IFAT) was used to detect Neospora caninum and Toxoplasma gondii antibodies. Herein, serum samples from 305 sheep were evaluated, being 29 (9.5%) and 157 (51.5%) seropositives to N. caninum and T. gondii, respectively. Seven (29.1%) and five (20.8%) out of 24 dogs were seropositives to N. caninum and T. gondii, respectively. There were no differences among the sheep serology for N. caninum and reproductive problems, management and animal feeding variables, neurological problems and presence of other animals species on the farm (P>or=0.05). The simultaneous frequency of antibodies between N. caninum and T. gondii was 5.2% in the herds. Age, breed, farm size, semi-intensive activity, mineral salt supplementation, water origin, stage of the pregnancy when reproduction problems occurred, neurological problems in lambs, presence of rodents in the food room and pasture cat access were identified as associated factors for the occurrence of toxoplasmosis in sheep (P<0.05). There were no differences among the seropositivity in dogs for N. caninum and T. gondii and breed, age and sex (P>or=0.05). The present work is the first report on serum prevalence of N. caninum in sheep from the state of Paraná, Brazil.     

Characterization of a murine model of intranasal infection suitable for testing vaccines against C. abortus

Mouse models have been widely used to test candidate vaccines against Chlamydophila abortus infection in mice. Although the induction of a systemic infection by endogenous or intraperitoneal inoculation is a useful tool for understanding the immune mechanism involved in the protection conferred by the vaccination, a different approach is necessary to understand other factors of the infection, such as mucosal immunity or the colonization of target organs. To test whether C. abortus intranasal model of infection in mice is a useful tool for testing vaccines in a first group of experiments mice, were infected intranasally with C. abortus to characterize the model of infection. When this model was used to test vaccines, two inactivated experimental vaccines, one of them adjuvated with QS-21 and another with aluminium hydroxide, and a live attenuated vaccine (strain 1B) were used. Non-vaccinated control mice died within the first 8 days, after displaying substantial loss of weight. Histologically, the mice showed lobar fibrinopurulent bronchointerstitial pneumonia. Prior immunization with QS-21 adjuvated vaccine or 1B vaccine presented mortality and the recipients showed a greater number of T cells in the lesions, especially CD8(+) T cells, than the control mice and mice immunized with vaccine adjuvated with aluminium hydroxide. The results confirm that the C. abortus intranasal model of infection in mice is a useful tool for testing vaccines.