Falla en la eficacia de dos formulaciones de ivermectina contra Psoroptes ovis (Hering, 1838) en ovinos / Failure of efficacy of two ivermectin formulations against Psoroptes ovis (Hering, 1838) in sheep

Resumen El presente trabajo evaluó la relación entre la eficacia y la farmacocinética de dos formulaciones comerciales inyectables de ivermectina (IVM) en ovinos merino adultos artificialmente infestados con Psoroptes ovis. Los animales fueron tratados por vía subcutánea con IVM 1 % en dos dosis con un intervalo de aplicación de 7 días, (0.2 mg/kg) o con una única dosis de IVM 3.15%, (1.05 mg/kg). Se realizaron conteos semanales de ácaros vivos mediante raspajes de piel entre el día 0 y 28 post-tratamiento para determinar la eficacia de los tratamientos, y se tomaron muestras de sangre para medir las concentraciones de IVM en plasma. Se observó una disminución significativa en los conteos de ácaros a partir del día 14 post-tratamiento, sin embargo, se encontraron ácaros vivos en todos los muestreos para ambos grupos. En el Grupo IVM 1%, la máxima eficacia se observó el día 28 post tratamiento (93.3%), mientras que en el Grupo IVM 3,15% este registro se obtuvo el día 21 (95.9%). Mayores concentraciones de IVM fueron observadas en los animales tratados con la formulación 3.15 %. La falla para obtener una cura parasitológica tras el tratamiento con ambas formulaciones de IVM puede ser indicativo de la presencia de ácaros resistentes a este principio activo.

Abstract The current work evaluated the relationship between efficacy and pharmacokinetics of two commercial injectable formulations of ivermectin (IVM) in adult merino sheep artificially infested with Psoroptes ovis. Animals were treated subcutaneously with IVM 1% formulation (two doses on days 0 and 7) at 0.2 mg / kg or with a single dose of IVM 3.15% preparation at 1.05 mg / kg. Live mites were counted weekly by performing skin scrapings between days 0 and 28 post-treatment to determine the efficacy of each IVM formulation. Blood samples were taken up to 35 days post-treatment to measure IVM plasma concentrations. A significant decrease in mite counts was observed from day 14 post-treatment. However, live mites were found in all samples for both groups throughout the entire trial. After IVM 1% administration, the highest effcacy was observed on day 28 (93.3% whereas in the IVM 3,15% group was obtained on day 21 post treatment (95.9%). Higher IVM plasma concentrations were observed in animals treated with the IVM 3.15% formulation. Failure to obtain a parasitological cure after treatment with both IVM formulations may reflect the presence of resistant mites to this drug.

Efecto in vitro del extracto crudo de un estreptomiceto causante de sarna común de papa en Sinaloa, México / In vitro effect of the crude extract of a potato common scab streptomycete in Sinaloa, Mexico

Abstract A strain isolated from potato common scab superficial lesions in El Fuerte Valley in northern Sinaloa, Mexico, was identified by 16S rRNA and morphological methods. Moreover, the effects of the crude extract of strain V2 was evaluated on radish and potato. The isolate was similar to Streptomyces acidiscabies in its morphological properties; however, the 16S rRNA gene sequence of strain V2 was neither 100% identical to this species nor to the streptomycetes previously reported in Sinaloa, Mexico. Strain V2 did not amplify any specific PCR products for genes necl and tomA, which have been found and reported in S. acidiscabies. Strain V2 produced a PCR product for the txtAB operon, which is related to the production of thaxtomin. In vitro assays using crude thaxtomin extract and a spore suspension of the organism caused necrotic symptoms on radish and potato, which were highly virulent in potato. This study reports that Streptomyces sp. V2 has a toxigenic region (TR) that is associated with the thaxtomin gene cluster.

Resumen Se aisló una cepa de una lesión superficial de sarna común de la papa en un ejemplar procedente del Valle del Fuerte, en el norte de Sinaloa, México. La cepa fue identificada por secuenciación del gen 16S ARNr, y por sus características morfológicas. Los efectos del extracto crudo de dicha cepa, llamada V2, fue evaluado en papa y rábano. El aislado fue similar a Streptomyces acidiscabies en sus características morfológicas, pero la secuencia del gen 16S ARNr de la cepa V2 no fue 100% idéntica a la de dicha especie, ni tampoco a las de cepas identificadas dentro de este taxón previamente en Sinaloa, México. La cepa V2 no amplificó los productos específicos de PCR de los genes nec1 y tomA, los cuales sí se han reportado en S. acidiscabies. La cepa V2 amplificó el producto de PCR para del operón txtAB, relacionado con la producción de taxtomina. A través de ensayos in vitro usando un extracto crudo de taxtomina y una suspensión de esporas del organismo aislado se verificó la producción de síntomas necróticos en rábano y papa, con mayor virulencia en esta última especie. Este estudio indica que Streptomyces sp. V2 tiene una región toxigénica (TR) asociada con el cluster de genes de taxtomina.

Genetic Diversity of the Pear Scab Fungus Venturia nashicola in Korea

Scab disease caused by Venturia nashicola is of agroeconomic importance in cultivation of Asian pear. However, little is known about the degree of genetic diversity in the populations of this pathogen. In this study, we collected 55 isolates from pear scab lesions in 13 major cultivation areas in Korea and examined the diversity using sequences of internal transcribed spacer (ITS) region, β-tubulin (TUB2), and translation elongation factor-1α (TEF-1α) genes as molecular markers. Despite a low level of overall sequence variation, we found three distinctive subgroups from phylogenetic analysis of combined ITS, TUB2, and TEF-1α sequences. Among the three subgroups, subgroup 1 (60% of isolates collected) was predominant compared to subgroup 2 (23.6%) or subgroup 3 (16.4%) and was distributed throughout Korea. To understand the genetic diversity among the subgroups, RAPD analysis was performed. The isolates yielded highly diverse amplicon patterns and none of the defined subgroups within the dendrogram were supported by bootstrap values greater than 30%. Moreover, there is no significant correlation between the geographical distribution and the subgroups defined by molecular phylogeny. Our data suggest a low level of genetic diversification among the populations of V. nashicola in Korea.

Deoxynivalenol in wheat and wheat products from a harvest affected by fusarium head blight

Abstract Fusarium head blight is an important disease occurring in wheat, caused mainly by the fungus Fusarium graminearum. In addition to direct damage to crops, reduced quality and yield losses, the infected grains can accumulate mycotoxins (toxic metabolites originating from prior fungal growth), especially deoxynivalenol (DON). Wheat crops harvested in 2014/2015 in southern Brazil were affected by high levels of Fusarium head blight. In this context, the aim of this study was evaluate the mycotoxicological quality of Brazilian wheat grains and wheat products (wheat flour and wheat bran for DON. DON contamination was evaluated in 1,504 wheat and wheat product samples produced in Brazil during 2014. It was determined by high performance liquid chromatograph fitted to a mass spectrometer (LC-MS / MS). The results showed that 1,000 (66.5%) out of the total samples tested were positive for DON. The mean level of sample contamination was 1047 µg.kg-1, but only 242 samples (16.1%) had contamination levels above the maximum permissible levels (MPL) - the maximum content allowed by current Brazilian regulation. As of 2017, MPL will be stricter. Thus, research should be conducted on DON contamination of wheat and wheat products, since wheat is a raw material widely used in the food industry, and DON can cause serious harm to public health.

Therapeutic effect of early scab-cutting combined with axis-like abdomen skin flap implanting in patients with wrist deep electrical burns / 中国基层医药

Objective To observe therapeutic effects of early scab-cutting combined with axis-like abdo-men skin flap implanting in patients with wrist deep electrical burns.Methods Retrospective study was employed to analyze 70 patients received axis -like abdomen skin flap implanting for wrist deep electrical burns.All the cases were separated with early scab-cutting group(35 cases)and delayed scab-cutting group(35 cases),according to types of skin flap implanting.The therapeutic effect for the two groups were evaluated with rate of infection,duration of healing,living rate of skin flap,grade of skin burning,and rate of amputate.Results In the early scab -cutting group,the rate of infection was 11%,the duration of healing was(24.0 ±6.0)days,the rate of amputate was 3%,the living rate of skin flap was 97.0%,the wound healing of class A was 94.3%.In the delayed scab-cutting group,the data were respectively 31%,(35.0 ±7.4)days,17.0%,31% and 28.6%.Compared with the data of the two groups,the difference had statistical significance(the chi-square value or T value were respectively 4.151,6.831,3. 968,31.895,3.968.All the P values was less than 0.05).Conclusion Early scab-cutting combined with varied sorts of skin flap implanting shown great benefits for treatment of wounded and facilitate rehabilitation in function of wrist,which suggest decrease rate of complications and minimized hospitalized duration.

DETECCIÓN Y CUANTIFICACIÓN DE Spongospora subterranea f. sp. subterranea EN PLANTAS SEÑUELO Y CULTIVOS DE PAPA EN COLOMBIA MEDIANTE qPCR / Detection and Quantification of Spongospora subterranea f. sp. subterranea in Bait Plants and Potato Fields in Colombia using qPCR

La sarna polvosa de la papa (Solanum tuberosum, S. phureja) causada por Spongospora f. sp. subterranea (Sss), es una de las enfermedades más limitantes de este cultivo. En Colombia, se han empleado diferentes métodos de detección asintomática de Sss, incluyendo bioensayos con plantas señuelo, PCR de ITS y pruebas de ELISA. Sin embargo, sus niveles de sensibilidad son bajos o requieren tiempos extensos. Una alternativa para complementar dichas herramientas es la PCR cuantitativa en tiempo real (qPCR). En este trabajo se evaluó dicha técnica utilizando los juegos de cebadores SsTQF1-SsTQR1; Spon421F-Spon494R y SscolF-SscolR (diseñados en este estudio), bajo la metodología de SYBR Green®; mientras que con Taqman® se evaluaron los cebadores SponFSponR y la sonda SponP. Una vez determinada la funcionalidad de los cebadores, se descartó por inespecificidad, el par Spon421F-Spon494R ; para los restantes se realizaron curvas estándar basadas en diluciones seriadas de quistosoros. Las pruebas de qPCR detectaron a Sss en las 20 muestras evaluadas de plantas señuelo de Nicotiana benthamiana y papa, utilizando los cebadores SsTQF1-SsTQR1 (Ct: 10,57-29,34) y SscolF-SscolR (Ct: 14,39-34,08); mientras que 19 de las muestras fueron positivas con SponF-SponR-SponP (Ct: 15,63-38,93). A partir de 20 muestras de raíces de papa de cultivos de La Unión (Antioquia, Colombia), fue posible detectar el patógeno en 17 de ellas con SscolF-SscolR, estimándose una concentración de 6470 a 1,39 x 10(10) quistorosos/mL. Estos resultados indican la ocurrencia de altos niveles de inóculo de Sss en esta región y enfatizan en la necesidad de fortalecer los programas de certificación de tubérculo-semilla en Colombia.

In recent years, potato crops (Solanum tuberosum, S. phureja) have been seriously affected by powdery scab; a disease caused by Spongospora subterranea f.sp. subterranea (Sss). In Colombia, asymptomatic detection of Sss has been achieved with bait plants, PCR of ITS regions and ELISA tests. Unfortunately, these techniques have low sensitivity and may require long processing times. In this work, Quantitative real time PCR (qPCR) was tested for detection of Sss using different sets of primers. Primers SsTQF1-SsTQR1, Spon421F-Spon494R and SscolF-SscolR (designed in this study), were tested using SYBR Green®, while primers SponFSponR were tested using the Taqman® probe SponP. Primers Spon421F-Spon494R were discarded due to lack of specificity. Standard curves were obtained from serial dilutions of cystosori. The 20 N. benthamiana and potato bait plants evaluated tested positive for Sss using primers SsTQF1-SsTQR1 (Ct: 10.57-29.34) and SscolF-SscolR (Ct: 14.39-34.08) and 19 samples were positive with primers SponF-SponR-SponP, with Ct values ranging between 15,63 and 38,93. Sss was detected in 17 out of 20 root samples from potato crops in La Unión (Antioquia) using primers SscolF-SscolR, with an estimated concentration of 6470 to 1,39x10(10) cystosori/ mL. These results suggest high levels of Sss in the potato fields from this region and recall the importance of strengthening seed-certification programs in Colombia.

Evaluación de microorganismos con potencial de promoción de crecimiento vegetal y biocontrol de Spongospora subterranea / Evaluation of microorganisms with potential for plant growth promotion and biological control of Spongospora subterranea

La sarna polvosa de la papa es causada por el patógeno Spongospora subterranea, que disminuye la calidad y producción de tubérculos y facilita la entrada de otros patógenos. Esta enfermedad afecta las principales zonas productoras del mundo, debido a la falta de tratamientos efectivos contra el patógeno y al comercio de tubérculos-semilla infectados. Algunas investigaciones indican que los agentes biocontroladores podrían contribuir a reducir la actividad de S. subterranea a través de efectos sobre la viabilidad de sus quistosoros o mediante efectos estimulantes del crecimiento de la planta. En este estudio se emplearon bacterias aisladas del interior de raí­z, rizósfera y superficie de tubérculos de un cultivo de papa ( Solanum tuberosum variedad Diacol Capiro) y seleccionadas por su capacidad para producir indoles totales y quitinasas. En estudios paralelos se determinó su capacidad para promover la velocidad de germinación en brotes de tubérculos o para controlar S. subterranea en raíces y promover el crecimiento vegetal de plántulas en invernadero. La mayoria de los aislamientos evaluados incrementraron la longitud de brotes de tubérculos en el laboratorio. En el invernadero, en suelo no estéril y en presencia del patógeno, se encontró que 2 de los 10 aislamientos seleccionados por su capacidad para producir indoles totales y quitinasas, presentaron promoción de crecimiento vegetal y posible biocontrol del patógeno. Estos resultados sugieren un gran potencial para la selección de microorganismos biocontroladores y desarrollo de bioproductos a partir de recursos microbiológicos locales.

The powdery scab of potato is caused by the pathogen Spongospora subterranea which reduces the quality and yield of tubers and facilitates the establishment of other pathogens. This disease affects main potato production zones in the world, because there is not a completely effective and available control method against the disease, and due to the trading of infested seed tubers. Some research suggests that biological control agents could reduce the activity of S. subterranea through effects on the viability of their cystosoris or zoospores or by stimulating plant growth. In this research, bacteria previously isolated, from inside the roots, the rhizosphere and tuber peel of potato plants (Solanum tuberosum var. Diacol Capiro), were used, and then selected according to their capacity for producing total indoles and chitinases. Here was tested in parallel studies the capacity of nine bacterial isolates differing in total indole and chitinase production, for its capacity at increasing tuber sprout length and in promoting plant growth and biocontrol of S. subterranea . Inoculated in excised minitubers in laboratory most indole producing isolates tested resulted in increased tuber sprout length. In the greenhouse assay, in non-sterile soil and under a high pathogen pressure, two of the ten isolates selected because for their ability to produce total indoles and chitinases, showed plant growth promotion and possible biocontrol of the pathogen. These results suggest a great potential for the selection of biocontrol microorganisms and the development of new bioproducts from local microbial resources.

Occurrence of Strawberry Scab Caused by Cladosporium herbarum in Korea

A black scab was observed on strawberry(Fragaria ananassa) in plastic film houses around Jinju area during the winter of 2000. The disease started from leaves then moved to calyx and runner. At the beginning, the infected area started with small dark brown spots then gradually expanded. The pathogenic fungus was purely isolated from the diseased leaves, calyx and runner. The fungus was inoculated to test Koch's postulates and proved to be the causal agent of the disease. The isolated fungus grew readily on potato dextrose agar, forming dark green to dark gray colonies. The optimum temperature for mycelial growth was about 25degrees C. The diameter of growing hyphae was 3.8~5.6 microm. Conidia were ellipsoidal, ovoid or subspherical, mostly one-celled but occasionally septate. The size of conidia were 4.1~11.7x3.8~5.3 1-cell, 9.3~18.8x4.0~7.4 microm 2-cell and formed in long branched chains on the erected conidiophores which were dark brown and variable in length between 28.8~236.2x3.0~6.2 microm in size. The fungus was identified as Cladosporium herbarum on the basis of its morphological characteristics. The black scab disease of strawberry caused by C. herbarum has not been reported in Korea previously.

Occurrence of Sword bean Scab Caused by Cladosporium cucumerinum in Korea

A black scab disease occurred on sword bean (Canavalia gladiata) in plastic film houses around Chinju area during the spring season of 1999. The disease started from flower bud, then moved to flower stalk, pod, petiole, cirrus, stem and leaves. The lesions started with small dark brown spots then were gradually expanded. Severely infected plants reached 37.4% of whole plant covered with scab. Numerous conidia were produced on the diseased flower disk, pod, floral axis, stem and leaves. Most of the conidia were appeared to be readily dispersed in the air, but the mycelia were not suggested causing of sooty mold by ectoparasitism. A fungus was isolated from the diseased stem, and inoculated to healthy plants to satisfy the Koch's postulates and proved the fungus was the causal agent of the disease. The isolated fungus grew on potato dextrose agar, forming greenish black to pale brown colonies. Conidia were ellipsoidal, fusiform or subspherical, mostly one-celled but occasionally septated. The conidia were 3.9~34.1x2.7~5.1microm in size and formed in long branched chains on the erected conidiophores which were pale olivaceous brown and variable in length between 7.2~210.7microm in size. Ramoconidia were 7.6~29.2x3.2~14.4microm in size. The fungus was identified as Cladosporium cucumerinum based on the above morphological characteristics. The optimum temperature for mycelial growth and conidial formation was about 15 to 25degrees C. Cladosporium scab of sword bean caused by the fungi has not been reported in Korea previously.

The Selection of Thrombin-specific scAbs by Alternative Panning Strategy / 微生物学通报

Specific scAbs could be obtained through biopanning from phage antibody libraries by use of antigens as target molecules. scAbs specific to thrombin were separated from mouse antibody library by the panning strategy of alternating liquid-solid phase in this paper. Thrombin was biotinylated by photobiotin at first, then avidin-coated magnetic beads were utilized to isolate specific scAbs. The eluted phages were amplified and subject to the second round panning in microtiter plate to remove the unspecific reombinant phages. 4 specific scAbs were separated from 23 phage clones after four rounds of alternative panning.