A comparative study of lesions caused by different parasitic stages of Boophilus Microplus (Canestrini) in the skins of naturally infested taurine and zebuine hosts. The correlation of tick resistence with mast cell counts in the host's skin

Biópsias de pele lesada por larvas, ninfas e fêmeas engurgitadas de Boophilus microplus foram colhidas de cinco Bos taurus da raça Holandesa e de cinco Bos indicus da raça Gir, adquiridos na mesma propriedade, com aproximadamente 23 meses de idade, e colocados em convivência no mesmo pasto durante 90 dias que precederam este ensaio. O grau de susceptibilidade ao ácaro foi estimado previamente, sendo os zebuínos cerca de 15 vezes mais resistentes que os taurinos. As biópsias foram colhidas de modo que o parasito ficasse localizado no centro do fragmento de pele. Essas peças foram fixadas em formalina a 10% durante 24 h e processadas pelos métodos usuais em histologia seguindo-se a coloração pela técnica da Hematoxilin-Eosin ou do “tricrômico” de Masson. Não foram constatadas diferenças morfológicas que pudessem ser relacionadas aos diferentes graus de resistência ao parasito entre os taurinos e zebuinos. Biópsias foram colhidas de zonas não lesadas, na região da virilha dos cinco taurinos e dos cinco zebuínos, fixadas em subacetato de chumbo a 1% em solução de etanol 50%, contendo 1% de ácido acético, por 24 h. A seguir os fragmentos foram processados pelas técnicas usuais em histologia e corados pelo método do azul de toluidina 0,1%. Os mastócitos foram contados comparativamente em 80 campos microscópicos, em aumento de 100 vezes. Os resultados mostram que os zebuínos tem mais que o dobro do número de mastócitos dérmicos quando comparado com o encontrado nos taurinos. Esses resultados sugerem que os mastócitos dérmicos possam, pelo menos em parte, participar dos mecanismos de resistência dos bovinos ao Boophilus microplus.Biopsies of skin injuries caused by larvae, nymphs, unengorged and engorged females of Boophilus microplus were collected from five Bos taurus and five Bos indicus steers, which had been bom on the same ranch, aged about 23 months and had been grazing together in the same pasture during the preceding 90 days. Their susceptibilities to the tick had been previously estimated, being the taurine animals around fifteen times as susceptible as the zebuine ones. The biopsies were made in such a manner that the mouth pieces were in the center of the skin fragments. These were immersed for 24 hours in 10% formalin, then processed through usual histopathological techniques and stained either by the haematoxilin-eosin or by Masson’s “trichromic” procedures. No morphological differences were found capable of explaining the higher tick susceptibility observed for the taurine hosts as compared to the zebuine’s. Biopsies from non parasitized skin from the groin region of five B. taurus and five B. indicus steers were fixed in 1% lead subacetate, plus 50% ethanol, plus 1% acetic acid, for 24 hours, which they were histologically processed and stained in 0.1 % toluidin blue. The mast cells were comparatively counted in 80 microscope fields per sample with 100 diameters of magnification and the counts averaged more than twice as high in the zebuine than in the taurine host’s skins. These results strongly suggest that mast cells participate as important elements in the bovine host’s resistance to the cattle tick

Size of predatory mites and refuge entrance determine success of biological control of the coconut mite

Published online: 06 July 2016Predators face the challenge of accessing prey that live in sheltered habitats. The coconut mite Aceriaguerreronis Keifer (Acari: Eriophyidae) lives hidden beneath the perianth, which is appressed to the coconut fruit surface, where they feed on the meristematic tissue. Its natural enemy, the predatory mite Neoseiuluspaspalivorus De Leon (Acari: Phytoseiidae), is larger than this pest and is believed to gain access to the refuge only after its opening has increased with coconut fruit age. In the field, experimentally enlarging the perianth-rim-fruit distance beyond the size of the predators resulted in earlier predator occurrence beneath the perianth and lower numbers of coconut mites. On non-manipulated coconut fruits, the predators gained access to the prey weeks later than on manipulated ones, resulting in higher pest densities of coconut mites. Successful biological control thus critically hinges on the size of the predator relative to the opening of the prey refuge

EFICÁCIA DE DOIS SISTEMAS DE TRATAMENTO ANTI-HELMÍNTICO EM FILHOTES DE CÃES COM INFECÇÃO NATURAL

O objetivo do presente trabalho foi testar dois esquemas de tratamento para o combate da parasitose gastrintestinal em filhotes de cães recém-desmamados. Foram estabelecidos dois grupos de tratamento, ambos tratados com uma suspensão pamoato de pirantel e oxantel: grupo 1 - quatro desverminações com intervalos de 15 dias e grupo 2 -três desverminações, nos dias 0, 5 e 25 pós desmame. O primeiro tratamento apresentou redução de 98,2 % no número de ovos por grama de fezes (opg) de Toxocara canis, após a primeira desverminação. Cem por cento de redução de opg foi obtido após o segundo tratamento. No tratamento 2, foi obtido um resultado semelhante após três tratamentos. Para ovos de Ancylostoma sp. a formulação mostrou eficácia após a primeira dose para ambos os tratamentos preconizados. Estes resultados indicam que os esquemas de tratamento propostos poderiam ser adotados para combate das infecções por estes parasitas em animais recém-desmamados. Comparison of the efficacy of two systems of antihelminthic treatment in puppies with natural infection Abstract This work was developed to test two treatment outlines for gastrointestinal parasitosis control in weaned puppies. Two treatment groups were established, both treated with oxantel and pyrantel pamoate suspension: group 1 (four doses with 15-days intervals) and group 2 (three doses, at zero, 5th and 25th days). The first treatment presented reduction of 98.2 % on the number of eggs of Toxocara canis per gram of feces (epg) after the first dose. Complete epg reduction was observed after the second treatment, 15 days later. Similar result was obtained after the third dose for the treatment 2. Both treatment protocols showed effectiveness for eggs of Ancylostoma sp. after the first dose. These results indicate that both treatment outlines could be applied for the roundworm and the hookworm control in recently-weaned puppies

Role of ventral medullary catecholaminergic neurons for respiratory modulation of sympathetic outflow in rats

Abstract Sympathetic activity displays rhythmic oscillations generated by brainstem inspiratory and expiratory neurons. Amplification of these rhythmic respiratory-related oscillations is observed in rats under enhanced central respiratory drive or during development of neurogenic hypertension. Herein, we evaluated the involvement of ventral medullary sympatho-excitatory catecholaminergic C1 neurons, using inhibitory Drosophila allatostatin receptors, for the enhanced expiratory-related oscillations in sympathetic activity in rats submitted to chronic intermittent hypoxia (CIH) and following activation of both peripheral (hypoxia) and central chemoreceptors (hypercapnia). Pharmacogenetic inhibition of C1 neurons bilaterally resulted in reductions of their firing frequency and amplitude of inspiratory-related sympathetic activity in rats in normocapnia, hypercapnia or after CIH. In contrast, hypercapnia or hypoxia-induced enhanced expiratory-related sympathetic oscillations were unaffected by C1 neuronal inhibition. Inhibition of C1 neurons also resulted in a significant fall in arterial pressure and heart rate that was similar in magnitude between normotensive and CIH hypertensive rats, but basal arterial pressure in CIH rats remained higher compared to controls. C1 neurons play a key role in regulating inspiratory modulation of sympathetic activity and arterial pressure in both normotensive and CIH hypertensive rats, but they are not involved in the enhanced late-expiratory-related sympathetic activity triggered by activation of peripheral or central chemoreceptors

Search for charginos in e+e- interactions at sqrt(s) = 189 GeV

An update of the searches for charginos and gravitinos is presented, based on a data sample corresponding to the 158 pb^{-1} recorded by the DELPHI detector in 1998, at a centre-of-mass energy of 189 GeV. No evidence for a signal was found. The lower mass limits are 4-5 GeV/c^2 higher than those obtained at a centre-of-mass energy of 183 GeV. The (\mu,M_2) MSSM domain excluded by combining the chargino searches with neutralino searches at the Z resonance implies a limit on the mass of the lightest neutralino which, for a heavy sneutrino, is constrained to be above 31.0 GeV/c^2 for tan(beta) \geq 1.Comment: 22 pages, 8 figure