Efficacy of carvacrol on Rhipicephalus (Boophilus) microplus engorged female ticks (Canestrini, 1887) (Acari: Ixodidae): effects on mortality and reproduction.

The activity of carvacrol was evaluated in R. microplus female ticks by estimating the mean lethal concentration (LC50) and the acaricidal efficacy. Ticks were subjected to the Adult Immersion Test (AIT) to calculate LC50. From this value, the AIT was performed again at the concentrations of 20%, 40%, 60%, 80% and 100% of the LC50. Two control groups were established: one treated with distilled water and one with the solvent (ethanol 50%). The following parameters were evaluated: female weight before oviposition, egg mass weight, pre-oviposition and incubation period, hatching percentage, egg production index, fecundity rate, estimated reproduction, reduction in oviposition and hatching, and product efficacy. The obtained LC50 was 20.11 mg/mL. Egg mass weight, egg production index, pre-oviposition and fecundity rates of groups treated with 80% and 100% of LC50 were statistically different when compared to control groups. The product efficacy in groups treated with 100% of LC50 was 61.10%.

Molecular detection of Leishmania spp in Lutzomyia longipalpis in the city of Lavras, Minas Gerais, Brazil.

Leishmaniasis is a neglected disease that affects a large part of the world population. Knowing the sand fly fauna of a region is of fundamental importance for guiding health surveillance actions related to the prevention and control of leishmaniasis. A total of 86 specimens of sand flies (60 females and 26 males) were collected. Using the classification proposed by Galati (2003), the following species were identified: Lutzomyia longipalpis (Lutz & Neiva, 1912), Migonemyia migonei (França, 1920), Evandromyia cortelezzi (Brethes, 1923), Ev. sallesi (Galvão & Coutinho, 1939), Nyssomyia whitmani (Atunes & Coutinho, 1939), Psathyromyia lutziana (Costa Lima, 1932), Ev. lenti (Mangabeira, 1938), Brumptomyia sp. (França and Parrot, 1921), and Pressatia sp. (Mangabeira, 1942). Using PCR with internal transcribed spacer target to identify infected sand flies, five Lu. longipalpis females were infected with Leishmania spp. Despite the small number of specimens collected, considerable species diversity was found in the study area.

Sublethal concentrations of acetylcarvacrol strongly impact oocyte development of engorged female cattle ticks Rhipicephalus microplus (Canestrini, 1888) (Acari: Ixodidae).

Rhipicephalus microplus, commonly known as southern cattle tick, causes huge economic losses in the cattle industry. Its infestation affects the production of meat and milk and causes discomfort to hosts. In addition, it is the vector of Babesia spp. and Anaplasma spp. The most frequent method used to control these parasites is through synthetic acaricides. However, their indiscriminate use can be toxic for hosts and environment as well as cause selection of resistant ticks. Plant extracts and essential oils emerge as promising alternatives to manage tick infestation. Carvacrol, an aromatic monoterpene extracted from plants, has recognized antimicrobial, antioxidant, insecticidal, repellent and acaricidal activities. Acetylation of carvacrol is believed to enhance its nematicidal and acaricidal activities and to decrease its toxicity to hosts. Thus, the aim of this study was to evaluate the effect of different concentrations of acetylcarvacrol in the morphology of ovaries of engorged R. microplus ticks. The most remarkable morphological alterations found in the female germ cells were irregular and thicker chorion, decreasing in size and irregular shape of female germ cells (oocytes), cytoplasmatic vacuolization as well as ring-shaped nucleoli. These alterations were analyzed through a semi-quantitative method proposed in this study for ixodid ticks. Treatment group IV, which was exposed to 4.5 µL/mL of carvacrol acetate, showed the most significant alterations, and it was also statistically different when compared to control groups. Therefore, sublethal concentrations of acetylcarvacrol demonstrated to impact the reproductive system of R. microplus by causing several damages in the female germ cells. This would hinder the generation of new individuals, probably contributing for a long-term control of tick infestation.

The polymorphisms of genes associated with the profile of fatty acids of sheep / Os polimorfismos de genes associados ao perfil de ácidos graxos de ovinos

The present study aimed to evaluate the occurrence of polymorphisms in Diacylglycerol acyltransferase (DGTA-1 and 2), Fatty acid synthase (FASN), Stearoyl-CoA desaturase (SCD) genes and the Thioesterase domain of FASN (TE-FASN) gene that may be related to the lipid profile. In the experiment, a total of 84 sheep from different genetic groups were used. For the evaluation of the polymorphism of the genes, PCR-Single Strand Conformation Polymorphism (SSCP) technique and subsequent sequencing were used. In DGAT-2 gene, four genotypes were identified with the presence of 6 polymorphisms, with two (c.229T> C; c.255T> C) that resulted into the exchange of phenylalanine by leucine. In FASN gene, two genotypes were identified. In TE-FASN gene, three genotypes and 17 polymorphisms were identified. DGAT-1 and SCD genes did not reveal the occurrence of polymorphism. There was difference in relation to C14: 0, C18: 0 fatty acids and Δ9-desaturase C18 for DGAT-2 gene and of C18: 2ω6t for TE-FASN. There were differences among the genetic groups for C10: 0, C12: 0, C17: 0, C18: 2ω6t, C18: 3ω3, C20: 2, total of ω3, ω3/ω6 and atherogenicity index. There is occurrence of polymorphism of DGAT-2 and TE-FASN genes and these should be further studied in sheep since they revealed influence of the genotypes on the fatty acid profile.(AU)

O presente estudo teve o objetivo de avaliar a ocorrência de polimorfismos nos genes Diacilglicerol aciltransferase (DGTA1 e 2), Ácido graxo sintase (FASN), Estearoil-CoA dessaturase (SCD) e o Domínio da tioesterase do gene FASN (TE-FASN), que possam estar relacionados ao perfil lipídico. No experimento, foram utilizados um total de 84 ovinos de diferentes grupos genéticos. Para avaliação do polimorfismo dos genes, foi utilizada a técnica de polimorfismo de conformação de cadeia simples (PCR-SSCP) e posterior sequenciamento. No gene DGAT-2, foram identificados quatro genótipos com a presença de seis polimorfismos, com dois (c.229T>C; c.255T>C) que resultaram na troca da fenilalanina por leucina. No gene FASN, foram identificados dois genótipos. No gene TE-FASN, foram identificados três genótipos e 17 polimorfismos. Os genes DGAT-1 e SCD não revelaram a ocorrência de polimorfismo. Houve diferença em relação aos ácidos graxos C14:0, C18:0 e ∆9-desaturaseC18 para o gene DGAT-2 e de C18:2ω6t para TE-FASN. Houve diferença entre os grupos genéticos para C10:0, C12:0, C17:0, C18:2ω6t, C18:3ω3, C20:2, total de ω3, ω3/ω6 e índice de aterogenicidade. Há ocorrência de polimorfismo dos genes DGAT-2 e TE-FASN, e estes devem ser mais estudados em ovinos, pois revelaram influência dos genótipos sobre o perfil de ácidos graxos.(AU)

Molecular detection of Leishmania spp in Lutzomyia longipalpis in the city of Lavras, Minas Gerais, Brazil

Leishmaniasis is a neglected disease that affects a large part of the world population. Knowing the sand fly fauna of a region is of fundamental importance for guiding health surveillance actions related to the prevention and control of leishmaniasis. A total of 86 specimens of sand flies (60 females and 26 males) were collected. Using the classification proposed by Galati (2003), the following species were identified: Lutzomyia longipalpis (Lutz & Neiva, 1912), Migonemyia migonei (França, 1920), Evandromyia cortelezzi (Brethes, 1923), Ev. sallesi (Galvão & Coutinho, 1939), Nyssomyia whitmani (Atunes & Coutinho, 1939), Psathyromyia lutziana (Costa Lima, 1932), Ev. lenti (Mangabeira, 1938), Brumptomyia sp. (França and Parrot, 1921), and Pressatia sp. (Mangabeira, 1942). Using PCR with internal transcribed spacer target to identify infected sand flies, five Lu. longipalpis females were infected with Leishmania spp. Despite the small number of specimens collected, considerable species diversity was found in the study area.

Predicted philogeny, secondary conformational structure, and epitope antigenicity of immunological sequences in poultry.

Poultry production is faced with different types of stresses that are responsible for issues of animal welfare as well as for economic losses. Moreover, the immunity decreases when animals are stressed. In silico analyses are important in reducing the cost and in increasing the accuracy of scientific results. A bioinformatics tool was used to perform ontology studies on 15 different immunological sequences of poultry. The mRNA structures and sequences with maximum antigenic residues were also predicted. No homology was found between the sequences of poultry and mammals. These results helped in the prediction of new potential molecular markers. Of the 15 sequences that were analyzed, predictions could not be made for five because they were longer than 2500 nucleotides; for the remaining 10 sequences, 20 conformational structures per sequence were predicted and the most stable sequences were identified by their minimum free energy values. The highest antigenic epitopes were accepted by the maximum scores; 15 of the total 8934 epitopes that were predicted were analyzed. These results would aid future studies that use synthetic peptides or recombinants as markers or immunomodulators and would expand our understanding on how stress can modulate the immune system. These would also help in developing rapid diagnostic tools, in increasing animal welfare, biosecurity, and productivity, and also in developing of food additives and environmental enrichment for stress control, thereby, making animal production more sustainable.

Risk factors associated with seroprevalence of Neospora caninum in dogs from urban and rural areas of milk and coffee production in Minas Gerais state, Brazil.

This study was conducted to determine the seroprevalence of anti-Neospora caninum antibodies and to investigate the risk factors related to seroprevalence in dogs from urban and rural areas with distinct economic activities (milk and coffee production) in Minas Gerais state, Brazil. For this purpose, blood samples from 703 dogs were collected and questionnaires addressing epidemiological aspects were completed by dog-owners. The sera were analysed for anti-N. caninum antibodies by indirect fluorescent antibody tests (IFAT ≥ 1:50). Association between epidemiological aspects and seropositivity in dogs was evaluated with multivariate logistic regression models. A total of 80 (11·4%) dogs tested positive for N. caninum. In the multivariate logistic regression models, dogs aged >4 years, dogs used as guard dogs, dogs that spontaneously hunt, and history of bovine abortion were found to be greater risk factors for canine N. caninum infection. When we considered only dogs from rural areas, an association with seroprevalence was seen for milk farms, dogs not fed with commercial food, dogs that hunt, and dogs used as guard dogs.

Immune response of bovines stimulated by synthetic vaccine SBm7462 against Rhipicephalus (Boophilus) microplus.

Ten-month-old calves Bos taurus taurus were immunized with three doses of SBm7462 with saponin as an adjuvant at 30-day intervals and were evaluated for IgG isotypes, phenotype circulating lymphocytes and changes in the lymph nodes (LN). SBm7462 stimulated the production of predominantly IgG1-isotype IgG antibodies. The lymph nodes exhibited activation at the seventh day after the first immunization, with areas of paracortical and interfollicular hyperplasia and the early formation of germinal centers (GC). Fifteen days after the first immunization, the GC exhibited compartmentalization of cellular populations, a light zone (LZ), a dark zone (DZ) and a mantle. At the same time, hyperplasia of the medullary cords was observed with cells associating with DC cells. Seven days after the first immunization, apoptosis in the DZ and in the paracortical region became evident. By day 15, there was an increase in the medullary cords, which became more numerous at days 35 and 42. PAP-positive cells were found in the paracortical region, medullary cords and GC 7 days after the first immunization. At day 35, there were further strongly PAP-positive cells in the medullary cords. By comparison, none of these changes were observed in the lymph nodes of control groups at any of the days analyzed. The number of CD21(+) lymphocytes increased in the immunized groups after the first inoculation, with a maximum number observed at 15 and 10 days after the first and third immunizations, respectively. Compared to pre-immunization counts, the percentage of WC1(+) gammadelta T-lymphocytes displayed more variation, increasing 5 days after the second immunization but decreasing over the following days. According to the results, the synthetic anti Rhipicephalus microplus vaccine elicits a complete immune response being T-dependant.

Synthetic vaccine (SBm7462) against the cattle tick Rhipicephalus (Boophilus) microplus: preservation of immunogenic determinants in different strains from South America.

The synthetic vaccine SBm7462 is based on three immunogenic epitopes (4822, 4823 and 4824) contained within protein Bm86 derived from the Australian Yeerongpilly strain of the tick Rhipicephalus (Boophilus) microplus. Twenty strains of the tick originating from Brazil, Argentina, Colombia and Uruguay were analysed in order to identify differences compared with sequences present in components of vaccine SBm7462. For each parasite population, three cDNA fragments containing the nucleotides coding for the epitopes 4822, 4824 and 4823 were sequenced, and the amino acid sequences were deduced and compared with those of the homologous bm86 gene. The results indicate that the epitope sequences of vaccine SBm7462 are conserved in the South American populations of the tick. The conservation of such sequences is very important for the immunological response of different populations of R. (B.) microplus.