Structure and Mode of Action of Microplusin, a Copper II-chelating Antimicrobial Peptide from the Cattle Tick Rhipicephalus (Boophilus) microplus

Microplusin, a Rhipicephalus (Boophilus) microplus antimicrobial peptide (AMP) is the first fully characterized member of a new family of cysteine-rich AMPs with histidine-rich regions at the N and C termini. In the tick, microplusin belongs to the arsenal of innate defense molecules active against bacteria and fungi. Here we describe the NMR solution structure of microplusin and demonstrate that the protein binds copper II and iron II. Structured as a single alpha-helical globular domain, microplusin consists of five alpha-helices: alpha 1 (residues Gly-9 to Arg-21), alpha 2 (residues Glu-27 to Asn-40), alpha 3 (residues Arg-44 to Thr-54), alpha 4 (residues Leu-57 to Tyr-64), and alpha 5 (residues Asn-67 to Cys-80). The N and C termini are disordered. This structure is unlike any other AMP structures described to date. We also used NMR spectroscopy to map the copper binding region on microplusin. Finally, using the Gram-positive bacteria Micrococcus luteus as a model, we studied of mode of action of microplusin. Microplusin has a bacteriostatic effect and does not permeabilize the bacterial membrane. Because microplusin binds metals, we tested whether this was related to its antimicrobial activity. We found that the bacteriostatic effect of microplusin was fully reversed by supplementation of culture media with copper II but not iron II. We also demonstrated that microplusin affects M. luteus respiration, a copper-dependent process. Thus, we conclude that the antibacterial effect of microplusin is due to its ability to bind and sequester copper II.

Diagnoses of fipronil resistance in Brazilian cattle ticks (Rhipicephalus (Boophilus) microplus) using in vitro larval bioassays

Fipronil is a phenylpyrazolic insecticide that is widely used in agriculture and has been recently used to control the cattle tick, Rhipicephalus (Boophilus) microplus. Because of the serious problems associated with resistance to the available acaricides, this product has been used as an important alternative to control acaricide-resistant ticks. The objective of this work was to analyse the fipronil sensitivity of ticks that were collected from farms with a history of fipronil use by larval bioassays. A total of 11 Brazilian tick populations were studied: one population from Rio Grande do Sul, one population from Mato Grosso do Sul and nine populations from Sao Paulo. To validate the assays, susceptible reference strains, POA (Porto Alegre, Brazil) and Mozo (Dilave, Uruguay), and ticks from six different farms that never used fipronil were tested. The resistance of various tick populations to technical grade fipronil (95.3%) was primarily evaluated using the larvae immersion test (LIT) and the larval packet test (LPT), when a sufficient number of larvae was collected. Using the LIT, the resistance ratios (RR(50)) of the tick populations from Rio Grande do Sul and Mato Grosso do Sul were 14.9 and 2.6, respectively, and the populations derived from Sao Paulo had RR(50)s ranging from 2.5 to 6.9. Four populations were evaluated with the LPT, and two populations displayed lower RR(50), while other populations displayed higher RR(50) than those determined by the LIT. This article reports the first cases of fipronil resistance in Brazil and highlights the LIT as a more sensitive technique for the evaluation of fipronil resistance in R. (B) microplus ticks. We suggest the use of the LIT as an evaluation tool for monitoring fipronil resistance in the control programmes of R. (B) microplus. (C) 2010 Elsevier B.V. All rights reserved.

The effects of commodity dependence on the brazilian economy: a test of the dutch disease hypothesis

A doença holandesa tornou-se amplamente conhecida na década de 1960, quando a descoberta repentina de reservatórios de gás natural em território holandês, na região do mar do norte, transformou o país em uma economia rica em recursos. A desagradável consequência que proveio da recém-adquirida abundância de commodities foi o declínio da próspera indústria holandesa, que perdeu sua competitividade devido à valorização do florim holandês, como consequência do aumento do influxo de capital estrangeiro no país. Desde então este fenômeno tem sido observado em diversos países que possuem abundância de commodities. O objetivo desta tese é aplicar o modelo da doença holandesa ao Brasil, já que a maior economia da América latina poderá também ter de encarar a ameaça de se tornar prisioneira da “armadilha das commodities”, devido à sua abundância de recursos naturais. O autor revisa a bibliografia básica abordando o tema geral da doença holandesa e dá enfoque a estudos realizados anteriormente no Brasil. Além disso, os quatro maiores sintomas que caracterizam a doença holandesa são testados: (1) valorização das taxas de câmbio do real, (2) declínio do setor industrial, (3) crescimento do setor de serviços, e (4) aumento dos salários. Todos estes sintomas foram observados e podem ser comprovados através das abordagens de cointegração ou de correlação, com exceção do sintoma número dois. Ainda que estes resultados sejam significativos, há muito outros fatores determinantes que influenciam o desenvolvimento dos sintomas examinados, motivo pelo qual futuros estudos serão necessários para se obtiver conclusões definitivas sobre como o Brasil é afetado pela doença holandesa.

How to neutralize the adverse developmental effects of the Dutch disease?

This paper addresses the subject of the adverse developmental effects of the Dutch disease: the theory, the experience of Latin America over the last decade, and the economic policy management issues on what to do about it.

Estimates of genetic parameters for visual scores and their correlation with production and reproductive traits in Brahman cattle

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Anthelmintic efficacy of oral trichlorfon solution against ivermectin resistant nematode strains in cattle

Infected calves from two different rural estates in Brazil were studied to assess the anthelmintic efficacy of oral trichlorfon against naturally occurring ivermectin resistant parasitic nematode strains. In experiment 1, infected animals were from a region where ivermectin resistant populations of Haemoncus placei, Cooperia punctata,Cooperia spatulata and Trichuris discolor have recently been identified. Six calves with natural gastrointestinal nematode infections were treated with 48.5 mg/kg aqueous trichlorfon administered orally and six calves acted as a non-treated control group. In experiment 11 24 naturally infected calves were selected to enter one of four treatment groups, six animals each received: 48.5 mg/kg oral trichlorfon; 200 mu g/kg subcutaneous 1% ivermectin; 630 mu g/kg subcutaneous 3.15% ivermectin; or no treatment (control group). Gastrointestinal helminths were counted and identified post-mortem at 7 days (trichlorfon and 1% ivermectin treated and untreated animals) or 14 days (3.15% ivermectin treated and untreated animals) after administration of the test agents. Experiment I identified a high level efficacy for oral trichlorfon against four helminth species that have previously been shown to be ivermectin resistant in this geographical region: percentage efficacy was 99.82% against adult H. placei, 99.18% against C. punctata, 99.33% against C. spatulata, 81.06% against T. axei, 98.46% against Oesophagostomum radiatum and 100% against T. discolor. Trichlorfon also showed activity against the ivermectin (1% and 3.15%) resistant helminth species identified in experiment 11, attaining efficacy levels of 99.17% against H. placei, 98.46% against C punctata and 100.00% against T. discolor. These findings indicate that oral trichlorfon is an effective treatment option in the management of cattle infected with ivermectin resistant helminths. (C) 2009 Elsevier B.V. All rights reserved.

Preferential infection sites of Cysticercus bovis in cattle experimentally infected with Taenia saginata eggs

The preferential sites of infection of Cysticercus bovis were evaluated in the skeletal muscle and entrails of 25 cattle that were experimentally infected with Taenia saginata (2 x 10(4) eggs). Two other animals were not inoculated (control). Ninety days after inoculation, all the cattle were euthanized. The carcasses were deboned and dissected into 26 anatomical sections (masseter muscles, brain, tongue, esophagus, heart, diaphragm, lungs, liver, kidneys, spleen, top sirloin butt, bottom sirloin butt, outside round, top (inside) round, transversus abdominus, top sirloin cap, strip loin, full tenderloin, eye of round, knuckle, shoulder clod, foreshank, shank, chuck, back ribs, and tail muscles). The dissected tissues were sliced into 5 mm sections. From the 25 cattle, 9258 C. bovis (cysticerci) were recovered; 75.02% (6946) of these were recovered from skeletal muscles and 24.98% (2312) from the entrails. A high parasitism level was found in the shoulder clod (12.55%), heart (11.02%), liver (9.48%), masseter muscles (8.51%), chuck (8.25%), strip loin and full tenderloin (7.26%), knuckle (6.63%), and back ribs (5.53%), totaling 69.23% (5738) of all of the detected cysticerci. on the other hand, there was a low C. bovis parasitism level in the brain, spleen, tail muscles, kidneys, esophagus, and diaphragm, representing just 3.9% of the total number of cysticerci. Given these results, we conclude that specific skeletal musculature regions, such as the shoulder blade, chuck, strip loin and full tenderloin, knuckle, back ribs and top round, which are not officially examined in many countries, are effective sites to efficiently screen C. bovis infection. To date, these regions have not been considered as preferential sites of C. bovis infection. Based on our work, however, these regions deserve greater attention from health inspectors because they contained a greater number of Cysticercus than the other regions of carcasses that are parasitized by T. saginata larvae. (c) 2010 Elsevier Ltd. All rights reserved.

Toxoplasma gondii: Infection natural congenital in cattle and an experimental inoculation of gestating cows with oocysts

Two studies, of a natural infection and an experimental infection, were performed in order to study congenital transmission of Toxoplasma gondii in cattle. In the first study, 50 fetuses were harvested from gestating cows that were eutanasied at a municipal slaughterhouse in Jaboticabal, São Paulo state, Brazil. In the second study, 11 gestating cows were divided into four groups for inoculation with T. gondii: GI consisted of three cows inoculated with 1.0 x 10(5) oocysts during their first trimester of gestation; GII consisted of three cows inoculated with 1.0 x 10(5) oocysts during their second trimester of gestation; GIII consisted of three cows inoculated with 1.0 x 10(5) oocysts during their last trimester of gestation; and GIV consisted of two control cows, one during its first and the other during its second trimester of gestation. In both studies, the presence of T. gondii was confirmed both indirectly by immunofluorescence assay (IFAT). In the natural infection experiment, 18% (9/50) of the gestating cows were confirmed to have specific antibodies (IFAT - 1:64) against T. gondii. The bioassay was able to diagnose the presence of T. gondii in the tissue samples from three calves. In the second experiment, the nine cows from groups I, II and III presented with specific antibodies (IFAT) against T. gondii. In contrast, T. gondii could not be detected by IFAT, histopathological examination or the bioassay in any of the nine calves born to cows experimentally infected with T. gondii oocysts. Based on the results from both studies, we conclude that congenital infection of T. gondii in cattle, while infrequent, does occur naturally. The pathogenicity of the strain of T. gondii may influence the likelihood of this route of transmission. (C) 2010 Elsevier B.V. All rights reserved.

Organic matter fractions and soil fertility under the influence of liming, vermicompost and cattle manure

Os efeitos do vermicomposto de esterco de curral associado à calagem em atributos da fertilidade do solo foram avaliados através de experimento em vasos empregando um Latossolo Vermelho, distrófico, textura média. Cinco doses do vermicomposto (equivalentes a 0; 28; 42; 56 e 70 t ha-1, peso seco) e cinco doses de calcário (visando elevar a saturação por bases a: 20; 30; 40; 50 e 60%) foram combinadas em esquema fatorial, sendo as amostras de solo incubadas por 180 dias. Para comparação entre o vermicomposto e o esterco de curral, amostras do mesmo solo receberam o equivalente a 70 t ha-1 do esterco de curral que originou o vermicomposto e as cinco doses de calcário listadas anteriormente. Através do cálculo do Índice de Eficiência Agronômica, foi verificado que o potencial de fornecimento de K e de Mg pelo esterco é maior do que o do vermicomposto, e que o de P, é semelhante. O vermicomposto aumentou os teores de Ca2+ e de matéria orgânica (MO), os valores de pH em CaCl2 e a CTC a pH 7. Com o aumento das doses de vermicomposto houve diminuição do C-ácidos húmicos e aumento do C-humina e com a calagem o C-total não aumentou mas houve diminuição do C-ácidos húmicos.

Genetic associations between weight at maturity and maturation rate with ages and weights at first and second calving in Canchim beef cattle

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Association of an insulin-like growth factor 1 gene microsatellite with phenotypic variation and estimated breeding values of growth traits in Canchim cattle

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Genotype-environment interaction for post-weaning traits in Nellore beef cattle

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Whole-genome analysis for backfat thickness in a tropically adapted, composite cattle breed from Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Genetic analysis on growth and carcass traits in Nelore cattle

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Genetic associations between age at first calving and heifer body weight and scrotal circumference in Nelore cattle

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)