Techniques and parameters used in compatibility tests between Beauveria bassiana (Bals) Vuill and in vitro phytosanitary products

The objective of this work was to test and compare different techniques used in tests for compatibility between the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuill and phytosanitary products, in order to develop a protocol for in vitro tests. Four modes of contact were studied between B bassiana (CG432) and the fungicides iprodione (Rovral) 500 g litre(-1) SC) and azoxystrobin (Amistar) 500 g kg(-1) WG), and the insecticide endosulfan (Thiodan) 350 g litre(-1) EC), at three rates. The techniques consisted in incorporating the products into the culture medium (IM), combining the conidia into the products mix (MP) and spraying the products before (SB) and after (SA) inoculation of the fungus on Petri dishes. The fungitoxic effect of the products was studied on the basis of parameters such as germination, colony-forming units (CFUs), vegetative growth and sporulation. The effect of azoxystrobin on conidial germination was significantly higher in the IM technique than in the other techniques. With regard to CFUs, the IM and SB techniques showed the greatest differences relative to the control. Vegetative growth and sporulation were more affected when azoxystrobin was sprayed before the fungus was applied. At the commercial rate, iprodione had a greater effect on the CFU parameter in the IM and MP techniques, and on vegetative growth in the IM technique, than the other techniques used; however, there was no significant difference occurred between the techniques at the commercial rate with respect to germination and sporulation. Endosulfan was more toxic to germination in techniques SB and SA, and to the CFUs parameter in techniques IM and MP. As to vegetative growth and sporulation, regardless of rate, a more pronounced effect was observed in IM than in the other techniques. It can be inferred that there are differences between techniques and that a standardization of the compatibility tests is necessary. Another inference is that these techniques should reflect realistic exposure of the fungus to chemical formulations under field conditions.     

Oxidation of dietary polyphenolics by hydroperoxidase activity of lipoxygenase

Lipoxygenase, in the presence of hydrogen peroxide, produces the oxidative decomposition of quercetin, naringenin, and resveratrol, known antioxidant molecules. Quercetin was the molecule more efficiently oxidized, followed by resveratrol and naringenin. When this molecule was incubated in the presence of GSH, a quinoid derivative was produced. This compound was not obtained in the presence of naringenin or resveratrol, suggesting that in the presence of hydrogen peroxide and lipoxygenase, quercetin may be oxidized to a prooxidant species. When hydrogen peroxide was substituted by hydroperoxy linoleic acid, the same oxidative process was observed. This means that in food products in which lipoxygenase and linoleic acid are presents, quercetin may be oxidized to prooxidant species; in contrast, naringenin and resveratrol may constitute a valid additive for the prevention of the oxidative degradation of foods.     

Distinct Species Exist Within the Cercospora apii Morphotype

ABSTRACT The genus Cercospora is one of the largest genera of hyphomycetes. Cercospora apii sensu lato is the oldest name for a large complex of morphologically indistinguishable Cercospora spp. occurring on a wide host range. There are currently 659 recognized Cercospora spp., and names of another 281 morphologically identical species are included in the synonymy of C. apii sensu lato. Two of the species that belong to the C. apii complex, C. apii and C. beticola, cause Cercospora leaf spot on Apium graveolens (celery) and Beta vulgaris (sugar beet), respectively. In the present study, multilocus sequence data, amplified fragment length polymorphism analysis, and cultural characteristics were used as additional features to characterize morphologically similar Cercospora strains occurring on celery and sugar beet. From the data obtained, it is shown that C. apii and C. beticola, although morphologically similar and able to cross-infect each others' hosts, are distinct functional species that should be retained as separate entities. Furthermore, a third, as yet undescribed species of Cercospora was detected in celery fields in Korea and Venezuela, suggesting that additional undescribed species also may be found to cause Cercospora leaf spot on celery. A polymerase chain reactionbased diagnostic protocol distinguishes all three Cercospora spp.     

Determination of the effective dose of an experimental fasciolicide in naturally and experimentally infected cattle

The aim of the present study was to determine the effective dose of an experimental fasciolicide called compound alpha or 5-chloro-2-methylthio-6-(1-napthyloxy)1H-benzimidazole in experimentally and naturally infected cattle. In the first experiment, 24 fluke-free heifers were each infected with 800 metacercariae of Fasciola hepatica and re-infected on day 45 with other 600 cysts per animal. On day 75, when the animals had 4- and 10-week-old flukes respectively, they were divided into four groups (G) of six animals each according to fluke egg counts. Groups 1-3 received compound alpha at 10, 12 and 14 mg/kg/p.o., respectively. G4 remained as an untreated control. Twenty days after treatment, the animals were sacrificed for the recovery of flukes. Efficacy was assessed as a percentage of egg or fluke reduction relative to the untreated control. In the second experiment (naturally infected cattle), 24-year-old steers positive to F. hepatica eggs were blocked into four groups of five animals each. Groups 1-3 received compound alpha at 10, 12 and 14 mg/kg/p.o., respectively. Group 4 served as a non-treated control. All procedures to determine efficacy were carried out as mentioned in the first experiment. The results in the first study showed a percentage on egg reduction of 97.3, 100 and 100 and overall fluke reduction of 94.3, 100 and 100 for Groups 1-3, respectively. In the second study, the percentage of egg reduction was of 87.5, 99.1 and 100 and overall efficacy regarding fluke reduction was of 84.2, 99.6, and 100 for Groups 1-3, respectively. It is concluded that the effective dose selected for compound alpha was of 12 mg/kg/p.o. in cattle having an induced or natural F. hepatica infection.     

ELISA to determine anti-K99 pilus antibody in the sera of normal and diarrhoeic calves

An ELISA to detect circulating antibodies against K99 pili, a major attachment factor to intestinal epithelial cells of Escherichia coli in calves, was performed. Two methods of K99 pili purification were attempted. Best results in terms of purity of the K99 antigen were achieved following the method described by Karkhanis and Bhogal (1986). This procedure included a heat shock at 65°C during 25 min to release the pili and ultracentrifugation steps to purify the antigen. SDS-PAGE showed an 18 KDa major band, identified as the K99 pilus antigen after immunoblotting against reference antisera. The purified K99 antigen was then adsorbed to the ELISA microplates. High optical density was obtained in the ELISA using a pool of sera from immunized cows. No differences in antibody levels (P ≥ 0.05) could be detected between clinically healthy calves and those showing diarrhoea.     

Pharmacokinetics and milk penetration of ibafloxacin after intravenous administration to lactating goats

The pharmacokinetic behavior of ibafloxacin was studied after intravenous administration of a single dose of 15 mg/kg to 6 healthy lactating goats. Plasma concentrations of ibafloxacin were determined by high-performance liquid chromatography with fluorescence detection. The data for concentration versus time could best be described by a 2-compartment model. The mean plasma ibafloxacin clearance (and standard error) was 1.05 (0.10) L/h x kg. The mean steady-state volume of distribution was 1.65 (0.42) L/kg. The mean elimination half-life was 3.76 (0.30) h. Ibafloxacin penetration from the blood to the milk was poor. The ratio between the areas under the concentration-time curve of milk and plasma was 0.20 (0.01), indicating scant penetration of ibafloxacin into the milk.     

Full-term delivery of river buffalo calves (2n = 50) from in vitro-derived vitrified embryos by swamp buffalo recipients (2n = 48)

Field trials were carried out on the use of swamp buffaloes (2n = 48) as recipients of in vitro-derived vitrified river buffalo (2n = 50) embryos. River buffalo embryos were produced through a total in vitro production system using frozen semen from a top progeny-tested bull and slaughter-house-derived ovaries and cryopreserved by a vitrification technique. Recipient swamp buffaloes were Philippine carabaos selected on body condition, parity, and reproductive status and owned by village farmers. Eighty post-warmed riverine embryos were transferred non-surgically to 40 swamp buffalo recipients, of which three healthy riverine calves were born by normal delivery and one stillbirth, representing a 5.0% (4/80) full-term development and 10% (4/40) calving rate with 75% (3/4) normal and 25% (1/4) stillbirth. The results demonstrate that, under field conditions and despite the difference in chromosome number between the embryo and recipient, swamp buffaloes are potential surrogate mothers of imported, genetically superior river buffalo frozen embryos. Thus, embryo IVP-vitrification and transfer technology is a potential tool in the propagation of genetically superior buffaloes. Precautionary measures, however, are recommended to avoid dystocia and stillbirth.     

A health evaluation in a colony of captive collared peccaries (Tayassu tajacu) in the Eastern Amazon

This study pretends to determine baseline data on the health and mortality of a colony of captive collared peccaries in the Eastern Amazon (Belém, State of Pará, Brazil) during a 65-months survey. Thirty-nine out of 166 animals (23.5%) died and were examined post-mortem. Monthly mortality averaged 1.2%. The highest mortality rate was observed in newborns (74.4%). Abandonment by the mother and aggression were responsible for 24.1% and 13.8% of the total newborn deaths, respectively. Most frequent causes of non-neonatal death were food poisoning (50.0%) due to an episode of accidental bitter cassava leaves ingestion and traumatism due to aggressions between animals (10.0%). Results from serology for different infectious diseases showed that 4.9% (2/41) collared peccaries had antibodies against Brucella spp. and 9.8% (4/41) animals had antibodies to two different Leptospira spp. serovars, butembo and autumnalis. This is the first survey of morbidity and mortality in captive collared peccaries in the Amazon region.