First Report of a Leaf Blight Caused by Pyricularia pennisetigena on Cenchrus echinatus in Paraguay.

The genus Pyricularia contains several fungal species known to cause diseases on plants in the Poaceae family (Klaubauf et al. 2014; Wang et al. 2019). While sampling for P. oryzae during March-2015 and April-2018, common weed Cenchrus echinatus L. was observed with leaf lesions in and around experimental wheat fields in the departments of Canindeyú and Itapúa. C. echinatus samples from both locations displayed similar leaf lesions, varying from small light brown pinpoint to elliptical brown lesions with greyish center. Symptomatic leaves were surface disinfested and cultured on potato dextrose agar (PDA) amended with 1% gentamicin at 25°C. Two monosporic isolates were obtained, one from Itapúa (ITCeh117) and the other from Canindeyú (YCeh55). The isolates were subsequently grown on oatmeal agar (OA) and PDA under a 12-h photoperiod at 25°C and evaluated after ten days for colony diameter, sporulation, macroscopic and microscopic features. Colonies on OA reached up to 4.8 cm diameter and were light grey, whereas colonies on PDA reached up to 5.3 cm diameter and were brown with grey centers, with cottony mycelium and broad white rims. Mycelium consisted of smooth, hyaline, branched, septate hyphae 4-4.5 µm diameter. Conidiophores were erect, straight or curved, unbranched, medium brown and smooth. Conidia were solitary, pyriform, pale brown, smooth, granular, 2-septate, 32-33 × 9-10 µm; truncated with protruding hilum and varied in length from 1.0 to 1.5 µm and diameters from 2.0 to 2.2 µm. Both isolates were similar and identified as Pyricularia pennisetigena, according to morphological and morphometric characteristics (Klaubauf et al. 2014). Subsequently, genomic DNA was extracted from each isolate using the primers described in Klaubauf et al. (2014) to amplify and sequence the internal transcribed spacers (ITS), partial large subunit (LSU), partial RNA polymerase II large subunit gene (RPB1), partial actin gene (ACT), and partial calmodulin gene (CAL). Sequences from each isolate (YCeh55/ITCeh117) were deposited in GenBank with the following submission ID for ITS: MN947521/MN947526, RPB1: MN984710/MN984715, LSU: MN944829/MN944834, ACT: MN917177/MN917182, and CAL: MN984688/MN984693. Phylogenetic analysis was conducted using the software Beast v1.10.4. The results obtained from the concatenated matrix of the five loci placed these isolates in the P. pennisetigena clade. To confirm pathogenicity, each isolate was adjusted to 5×104 conidia/ml of sterile water and C. echinatus plants were sprayed with the conidial suspension for isolate YCeh55, ITCeh117 or sterile water using an oilless airbrush sprayer until runoff. The three treatments were kept in the greenhouse at 25-28°C and about 75% relative humidity under natural daylight. Each treatment included three to five inoculated plants and 10 leaves were evaluated per treatment. Symptoms were observed 8-15 days after inoculation and were similar to those originally observed in the field for both isolates, whereas the control plants remained asymptomatic. P. pennisetigena was re-isolated from the inoculated leaves fulfilling Koch's postulates. To our knowledge, this is the first report of leaf blight on C. echinatus caused by P. pennisetigena in Paraguay. The occurrence of P. pennisetigena in the region and its ability to infect economically important crops such as wheat and barley (Klaubauf et al. 2014; Reges et al., 2016, 2018) pose a potential threat to agriculture in Paraguay.

Construcción y evaluación de una sembradora de trigo para siembra directa y en el fondo del surco, con tracción animal

Con el objetivo de mejorar la calidad de siembra en el cultivo de trigo, se desarrolló y probó una sembradora, en dos sistemas de siembra: Siembra directa y siembra en el fondo del surco. En siembra directa se cubrio, con paja (3.5 t/ha) y se probaron combinaciones de los accesorios: rueda pisa paja, rueda compactadora y dos tipos de rejas (reja redonda y reja con cresta), con el propósito de evaluar porcentaje de suelo cubierto después de la siembra y emergencia de plántulas. Los mejores resultados se obtuvieron cuando se utilizó el accsorio pisa paja (75

de cobertura), lo que repercutió favorablemente en el porcentaje de emergencia (77

). En siembra en el fondo del surco se probaron distancias entre surcos y abertura de la aleta abre surco, con el propósito de evaluar emergencia de plántulas. el mayor porcentaje (80

) se obtuvo con 20 cm. de distancia entre surcos con una abertura de aleta de 10 cm.

Variacion del perfil enzimatico cardiaco en pacientes sometidos a cirugia mayor, en ausencia de compromiso miocardio / Variation of heart enzymatic profile in patients submitted to major surgery in absence of miocardial compromise

Para esta investigacion se seleccionaron 20 pacientes escogidos al azar, programados para cirugia electiva mayor y en quienes se aplicaron diferentes tecnicas de anestesia. La determinacion del perfil enzimatico cardiaco: CK, CK-MB, LDH, se hicieron en el pre y post-operatorio inmediato. Todos los pacientes fueron clasificados ASA I y II, todos fueron menores de 60 anos y cada uno fue monotorizado con cardiovisoscopio durante el acto anestesico. Ningun paciente presento signos de IAM durante el trans y postoperatorio. Se encontro que existe una gran variedad en la determinacion de las enzimas CK total y LDH, concluyendo que la LDH no sirve como ayuda en el diagnostico de IAM Post-operatorio mientras que la relacion CK-MB, CK total mantiene una gran especificidad en el diagnostico del IAM en el postoperatorio inmediato, con un promedio de variacion de -0,10