Lethal concentration of Cymbopogon citratus (Poaceae) essential oil for Dolops discoidalis and Argulus sp. (Crustacea: Argulidae)     

Elcimara Cardoso Pereira  Elzamara Castro Oliveira  Elen Monique Oliveira Sousa  Hugo Napoleão Pereira Silva  Lincoln Lima Corrêa  Rosa Helena Veras Mourão  Marcos Tavares-Dias  Lenise Vargas Flores Silva 《Journal of fish diseases》2020,43(12):1497-1504

This study investigated the acute toxicity (LC_50-24 hr) effects of the essential oil of Cymbopogon citratus for adult Argulus sp. and Dolops discoidalis, before and during oviposition. In vitro acute toxicity (LC_50-24 hr) was tested using 20, 40, 60, 80, 100, 120, 140 and 160 μg/L of C. citratus essential oil, and two control groups (one with cultivation tank water and one with cultivation tank water + alcohol) were used. Specimens of Argulus sp. and D. discoidalis submitted to acute toxicity were evaluated using histological procedures. The major chemical compounds of C. citratus essential oil were geranial (47.5%), neral (35.6%) and myrcene (6.7%). The LC_50-24 hr for Argulus sp. adults was 67.97 μg/L, while for D. discoidalis it was 59.55 µg/L. In the oviposition of both species of argulids, maximum mortality began with treatments of 140 μg/L, while the LC_50-24 hr for Argulus sp. and D. discoidalis was 83.98 μg/L and 82.48 μg/L, respectively. In both argulid species exposed to C. citratus essential oil, morphological alterations were observed only in the eyes, and they occurred in the ommatidium and rhabdomeres and were dependent on the concentration of C. citratus essential oil and the parasite species.  相似文献   

Application of morphometric measures in estimation of body weight and discrimination of Astyanax lacustris and Astyanax fasciatus     

Hortência Aparecida Botelho  Aline de Assis Lago  Alisson Lucrecio da Costa  Adriano Carvalho Costa  Rafael Vilhena Reis Neto  Zoraia Silva  Fagner Machado Ribeiro  Marcos Barcellos Caf  Rilke Tadeu Fonseca de Freitas 《Aquaculture Research》2019,50(9):2429-2436

The objective of this study was to verify the direct and indirect correlation between morphometric measures, ratios, body weight and yield in two lambari species Astyanax lacustris and Astyanax fasciatus and whether the discriminant analysis is capable of separating and allocating the species. We used 102 lambari yellow tail and 60 lambari red tail. The fish were weighed and submitted to the evaluation of the morphometric measurements. The direct and indirect effects were evaluated by the method of track analysis, considering weight at slaughter, weight of body parts and body yields as dependent variables and measures and morphometric ratios as explanatory variables. Astyanax lacustris presented higher height and body width, carcass yield and trunk, while A. fasciatus presented higher head yield and viscera weight. The discriminant analysis was able to classify 79.5% of the two species. Track analysis demonstrated that the morphometric measurements can be used for estimation of body and body components’ weight in A. lacustris and A. fasciatus. However, regarding the corporal yield; the morphometric measures were insufficient to explain the yield variations of the species.  相似文献   

MALDI-TOF MS identification of Prototheca algae associated with bovine mastitis     

Carlos E. Fidelis  Manoela Franke  Letícia C. R. de Abreu  Tomasz Jagielski  Mrcio G. Ribeiro  Marcos V. dos Santos  Juliano L. Gonalves 《Journal of veterinary diagnostic investigation》2021,33(6):1168

We evaluated the use of MALDI-TOF MS for the identification of 3 major, dairy-associated Prototheca species, namely, Prototheca bovis (formerly P. zopfii genotype 2), P. blaschkeae, and P. ciferrii (formerly P. zopfii genotype 1). The MALDI-TOF MS spectra established for those species were introduced into the reference spectra library of the Bruker Biotyper MALDI-TOF MS analysis software. Next, 31 Prototheca isolates from Holstein cows with mastitis, from herds located in the midwestern area of São Paulo State, Brazil, were subjected to MALDI-TOF MS profiling. MALDI-TOF MS allowed identification of 22 of 27 P. bovis and 3 of 4 P. blaschkeae isolates with scores >2.0, with 5 of 27 P. bovis and 1 of 4 P. blaschkeae isolates identified only to the genus level. With our extended algae database, MALDI-TOF MS can contribute to quick and effective speciation of Prototheca from mastitis cases.  相似文献   

Coarse and nano emulsions for effective delivery of the natural pest control agent pulegone for stored grain protection          下载免费PDF全文

Gilad Golden  Elazar Quinn  Eli Shaaya  Moshe Kostyukovsky  Elena Poverenov 《Pest management science》2018,74(4):820-827

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Spinosad‐mediated effects on the walking ability,midgut, and Malpighian tubules of Africanized honey bee workers          下载免费PDF全文

Marcos Pereira Lopes  Kenner Morais Fernandes  Hudson Vaner Ventura Tomé  Wagner Gonzaga Gonçalves  Franciane Rosa Miranda  José Eduardo Serrão  Gustavo Ferreira Martins 《Pest management science》2018,74(6):1311-1318

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First record of infection by Trypanosoma sp. of Colossoma macropomum (Serrasalmidae), a neotropical fish cultivated in the Brazilian Amazon     

Roselene Nogueira Rodrigues  Marcos Sidney Brito Oliveira  Marcos Tavares-Dias 《Journal Of Applied Aquaculture》2018,30(1):29-38

Fish farming has grown rapidly in Brazil over the last two decades, due in part to the availability of water and species with potential for cultivation, such as Colossoma macropomum. This farmed fish, however, can be affected by parasitic infections with high mortality rates (>35%). The main objective of the present study was to describe the first occurrence of the Trypanosoma species in Colossoma macropomum, which occurred in fish cultured in the Brazilian Amazon region, as well as to morphologically characterize the trypomastigotes and the impact of these hemoparasites on the body condition of the hosts. The trypanosomes found in the blood of Colossoma macropomum were morphologically characterized by the size of the trypomastigote form, indicating the presence of only one morphotype. Of the 39 hosts examined from one fish farming, 41.0% were infected by Trypanosoma sp., with low levels of infection (mean blood density of 3.7/μL). The condition factor of the asymptomatic hosts was not affected by hemoparasitism. There was no correlation between the abundance of Trypanosoma sp. and the condition factor and size of the hosts. Finally, our understanding of host-parasite interactions and the detection of emerging diseases are fundamental for aquaculture.  相似文献   

Genetic evaluation and selection index in tetraploid Brachiaria ruziziensis          下载免费PDF全文

Rosangela Simeão  Adriane Silva  Cacilda Valle  Marcos Deon Resende  Sérgio Medeiros 《Plant Breeding》2016,135(2):246-253

Half‐sib progenies of congo signal grass (Brachiaria ruziziensis Germain & Evrard, syn.: B. eminii, Urochloa ruziziensis) were analysed using a mixed model methodology. The objective was to estimate genetic and phenotypic parameters, predict individual genetic values, estimate correlations between characters associated with biomass production and forage nutritive value and use this information to determine the economic weights to compare three multiplicative selection indices. Individual narrow‐sense heritabilities corrected for inbreeding varied from 0.14 to 0.91 for characters associated with biomass production and from 0.04 a 0.24 for nutritional value characters. The correlations among characters associated with annual biomass production were of high magnitude. In contrast, biomass production characters were negatively correlated with crude protein, acid detergent fibre and lignin. Total dry matter yield, crude protein and regrowth ability were weighted separately in evaluations during wet and dry season or annually in selection indices. Index that considered characters annually resulted in better distribution of forage production along the year than indices that separated wet and dry season production.  相似文献   

Adaptation and Validation of Colorimetric Methods in Determining Ammonium and Nitrate on Tropical Soils     

Thales Meinl Schmiedt Sattolo  Rafael Otto  Eduardo Mariano  Marcos Yassuo Kamogawa 《Communications in Soil Science and Plant Analysis》2016,47(22):2547-2557

Inorganic nitrogen (N) determination in soil extracts is a useful tool in studying soil–N interactions. The main method used worldwide is the steam distillation, but colorimetric methodologies show advantages of being quick, simple, sensitive, and higher yield. However, they are subject to disruption when the extract has interfering organic N, limiting its application in tropical soil. The aim of this study is to evaluate colorimetric methods for the determination of NH₄⁺ (through Berthelot reaction) and NO₃^? + NO₂^? (through Griess-Ilosvay reaction) in saline extracts of tropical soils by addition of activated charcoal during the extraction process. It is recommended to use extraction solution of 2 mol L^?1 potassium chloride (KCl) and reaction time of 30 min. Validation parameters confirmed the best performance of the colorimetric methods, revealing results favorable to the addition of the activated charcoal in the extraction process to increase the accuracy and precision of the colorimetric methods.  相似文献   

Seven years of negative detection results confirm that Xylella fastidiosa,the causal agent of CVC,is not transmitted from seeds to seedlings     

Helvécio Della Coletta-Filho  Sérgio Alves Carvalho  Luis Fernando Carvalho Silva  Marcos Antonio Machado 《European journal of plant pathology / European Foundation for Plant Pathology》2014,139(3):593-596

Knowledge about the mechanism of transmission of systemic pathogens of citrus species is highly important for the safe movement of citrus germplasm, management of citrus mother trees, and also production of young plants. Among systemic pathogens of citrus, Xylella fastidiosa the causal agent of the citrus variegated chlorosis (CVC), is one the most important pathogens causing decline in tree vigour and productivity. Seven-year experiments were conducted to evaluate the hypothesis of seed-to-seedling transmission of X. fastidiosa. This bacterium was found colonizing the fruit (exocarp, central axis and mesocarp) and the seed parts (seed coat and endosperm plus embryo). After 7 years of PCR assay, no positive PCR detection of X. fastidiosa was confirmed in seedlings propagated from the seeds infected with X. fastidiosa. This result demonstrates the lack of seed-to-seedling transmission of this bacterium.  相似文献   

Clinical, histopathological and epidemiological study of canine straelensiosis in the Iberian Peninsula (2003–2007)     

Gustavo A. Ramírez  Jaume Altimira  Beatriz García  Marcos Fernández†  Miquel Vilafranca 《Veterinary dermatology》2009,20(1):35-41

Straelensiosis is a relatively new disease described in dogs and produced by a trombiculid larva known as Straelensia cynotis . Few cases have been reported in the English literature. Straelensiosis has been observed in Southern France and Northern Portugal causing a distinctive nodular dermatitis. The present study describes the clinical, histopathological and epidemiological features of 19 cases diagnosed as straelensiosis in the north of Spain and Portugal (2003–2007). A follow-up of the animals after diagnosis was carried out. Differences with previously described cases were observed, especially concerning epidemiology and histopathology. The grade of response to different treatments and new microscopic features are discussed. The study concludes that S. cynotis can cause a nodular dermatitis in rural and hunting dogs in Spain and Portugal and is associated with particular seasonal and geographical factors.  相似文献