First Report of Pectobacterium brasiliense causing soft rot on mizuna (Brassica rapa var. japonica) in the United States.

Mizuna (Brassica rapa var. japonica), a member of family Brassicaceae, is a leafy vegetable having phenolic and other compounds beneficial to human health, such as natural antioxidants (Khanam et al. 2012). In October 2020, a field of mizuna (variety: Early) on Oahu island was observed having 20-30% diseased plants. Four randomly selected infected mizuna plants, showing the symptoms of wilt and stem rot (Figure 1A-D), were collected and isolations were made to determine the pathogen. Small sections of infected stems were cut, surface sterilized with 0.6% sodium hypochlorite solution for 30 sec, followed by three consecutive rinses in distilled water. The tissues were macerated in a sterile 1.5 ml centrifuge tube containing 100 µl sterile water-macerated tissues were streaked onto crystal violet pectate medium (CVP) (Hélias et al. 2011) and incubated at 26 ± 2°C for 48 h. Isolated bacterial colonies that formed pits on the CVP plates were re-streaked onto dextrose peptone agar: Peptone (10 g/L), Dextrose (5 g/L) and Agar (17 g/L) (DPA-without tetrazolium chloride; Norman and Alvarez 1989) to obtain purified colonies for DNA isolation using DNeasy Blood and Tissue Kit (Qiagen, Germantown, MA). The two housekeeping genes (dnaA and gapA) were amplified and sequenced following the protocols used by Dobhal et al. (2020) and Boluk et al. (2020), for identity confirmation and phylogenetic analysis. Cleaned PCR products were sent to the GENEWIZ facility (Genewiz, La Jolla, CA) for sequencing of sense and antisense strands. The obtained sequences were aligned, manually edited, and consensus sequences were analyzed with BLASTn using the NCBI GenBank nucleotide and genome databases for identity confirmation. The BLASTn results demonstrated 100% query coverage of all four strains (PL248-PL251); and showed 100% identity of PL248 and PL249, and 99% identity of PL250 and PL251 with Pectobacterium brasiliense. All the sequences were submitted to the NCBI GenBank database under the following accession numbers: dnaA gene MW560271 - MW560274 (PL248 - PL251); and gapA gene MW560275 - MW560278 (PL248 - PL251). Pathogenicity was assessed by artificially inoculating 100 µl bacterial suspension of each strain (PL248 - 1.12x 108 CFU/ml; PL249 - 1.32x 108 CFU/ml; PL 250 - 1.2x 108 CFU/ml and PL251 - 1.15x 108 CFU/ml) onto four-week-old mizuna (variety: Leafy Asian Greens) plants in three replicates, using sterile pipette tips, which was stabbed into stem halfway and wrapped with parafilm. The inoculated plants were well maintained under controlled greenhouse conditions. As negative controls, three plants were inoculated with 100 µl distilled water. Soft rot and wilt symptoms (Figure 1E-H) were observed 24 hours post inoculation. No symptoms were observed on control plants (Figure 1F). All four strains were re-isolated from the inoculated plants and confirmed as P. brasiliense based on resequencing of the dnaA region and 100% homology with the sequences of original strain. In the phylogenetic tree (Figure 2), based on two housekeeping genes (dnaA and gapA), the bacterial strains from mizuna grouped with other P. brasiliense retrieved from the NCBI GenBank database. To our knowledge, this is the first report of P. brasiliense infecting mizuna plants in Hawaii or in the USA and is important because this species is one of the most aggressive pectolytic pathogens in the genus Pectobacterium. Understanding the diversity of different pectolytic phytopathogens is essential to formulating risk mitigation strategies as P. brasiliense could potentially pose a threat to additional vegetable crops, especially the crucifers vegetables (Arizala et al. 2019; Klair et al, 2021).

First Report of Bacterial Soft Rot Disease on Pak Choi (Brassica rapa subsp. chinensis) caused by Pectobacterium brasiliense in the United States.

Pak choi (Brassica rapa subsp. chinensis) is an important vegetable crop native to China, known for high water content and low caloric value, containing high quality of protein, carbohydrates, fiber, vitamins, minerals, and secondary plant metabolites (Acikgoz, 2016). A pak choi field (8,000 sq. ft.) on Oahu, Hawaii, was visited in May 2020. About 10% plants were infected and showed characteristic symptoms of soft rot, wet lesions, macerated infected stem and necrotic leaves (Figure1A-D); leading to the suspect of one of the most devastating bacterial pathogens within genus Pectobacterium (Boluk et al. 2020; Li et al. 2019; Arizala et al. 2020; Arizala and Arif, 2019). Four infected plants were collected from the field, and stems were surface sterilized with 0.6% sodium hypochlorite solution for 30 sec, followed by three consecutive rinses in distilled water. The stems were aseptically macerated, streaked on Crystal violet pectate medium (CVP) (Hélias et al. 2011), and incubated for 48 h at 26 ± 2°C. The peculiar morphological characteristic of pectolytic bacterial pathogen, forming pits on CVP, were observed (Meng et al. 2016) (Figure 1E). Purification of bacterial colonies were done by re-streaking of a single colony on dextrose peptone agar (DPA-without tetrazolium chloride; Norman and Alvarez 1989). DNA was isolated from bacterial cultures using the DNeasy Blood and Tissue Kit (Qiagen, Germantown, MA), respectively. Molecular identification of four strains (PL243-246) were performed by the sequencing region of the housekeeping gene dnaA (chromosomal replication initiation protein) using Pec. dnaA-F1/R1 primer set (Dobhal et al. 2020). The amplified PCR product was enzymatically cleaned using ExoSAP-ITTM (Affymetrix Inc, Santa Clara, CA), and sent for sequencing at the GENEWIZ facility (Genewiz, La Jolla, CA) using both forward and reverse primers. The dnaA gene sequences were aligned using Geneious, and manually edited to remove the errors. The consensus sequences were analyzed with the NCBI BLASTn tool and were deposited in the NCBI GenBank under the accession numbers MT899920-MT899923. The NCBI BLASTn report indicated that all the sequences shared 99-100% identity and query cover with Pectobacterium brasiliense accession numbers MN544627-29. A phylogenetic analysis, using Geneious, was performed with the dnaA sequences representing different Pectobacterium spp., all strains grouped within the clade of P. brasiliense (Figure 2; Arizala et al, 2020). A pathogenicity assay was carried out in three replications on pak choi grown in pots containing commercial pot mixture, and maintained in the controlled-greenhouse (temperature 26-30°C; relative humidity 50-58%). Three-weeks old plant stems were artificially inoculated with 100 µl bacterial suspensions of PL243 (1.3x 108 CFU/ml), PL244 (1.2x 108 CFU/ml), PL 245 (1.2x 108 CFU/ml) and PL246 (1.1x 108CFU/ml); control plants were inoculated with 100 µl of distilled water (Figure 1F). Two days after inoculation, the soft rot and wilting symptoms (Figure 1G-H), similar to the ones observed on the field, were developed for all four strains tested. Bacteria was successfully re-isolated from the inoculated plants; DNA was isolated, amplified, sequenced for dnaA region and analyzed for 100% homology with original strains, to fulfill Koch's postulates. Based on the molecular characteristics re-isolates were identical to the original strains. To the best of our knowledge, this is the first report of P. brasiliense on pak choi in the USA. Recent reports indicated that the pathogen could potentially pose a threat to cruciferous crops, therefore, highlighting a need to conduct a state-wide survey for pectinolytic bacteria, and implement better management strategies to combat the vegetable crop losses.

Degradación de poliestireno y polipropileno con microorganismos de vermicompost

Intenta determinar si los microorganismos contenidos en humus de lombriz de tierra servirían para la biodegradación de poliestireno y de polipropileno, con miras a emplearlos microorganismos aislados en un tratamiento a gran escala. Ambos materiales plásticos están presentes en los residuos domiciliarios en forma de envases descartables de alimentos, y una de sus posibles formas de minimización podría ser este tipo de degradación

Cirugía de revascularización coronaria con conductos arteriales. Técnica, resultados y seguimiento a cuatro años en 1.023 pacientes consecutivos / Total Arterial Coronary Revascularization. Techniques, Results and Four Years Follow Up in 1,023 Consecutive Patients

Objetivo. El propósito del presente trabajo fue analizar los resultados intrahospitalarios y tras 4 años en 1.023 pacientes consecutivos sometidos a cirugía de revascularización coronaria en los que se emplearon conductos arteriales: arteria radial y una o dos arterias mamarias internas. Método. Entre mayo de 1995 y mayo de 1998, 1.023 pacientes consecutivos fueron operados utilizando conductos arteriales, una o dos arterias mamarias y arteria radial. La mamaria izquierda fue empleada in situ, y la mamaria derecha como injerto libre o in situ, ambas en combinación con la arteria radial. Esta última fue conectada a la mamaria izquierda a través de una anastomosis en 'T' o 'Y' o, en menor proporción, emergiendo de la porción ascendente de la aorta. Resultados. Se realizaron un promedio de 3,2 puentes/paciente. La mamaria izquierda se utilizó en el 100 por ciento de los casos. La mamaria derecha se empleó en el 21,7 por ciento y la radial en el 100 por ciento de los pacientes. La mortalidad hospitalaria fue de 2,5 por ciento (26 pacientes) y 32 (3,1 por ciento) sufrieron infarto perioperatorio. Los primeros 62 pacientes fueron angiográficamente estudiados antes del alta y se obtuvo un 98,4 por ciento de permeabilidad en los conductos empleados. La media de seguimiento fue 25,0 ñ 9,6 meses (rango, 1-48 meses). Conclusiones. a) la cirugía de revascularización miocárdica empleando una combinación de arterias mamarias y radial es segura; b) los resultados intrahospitalarios y a mediano plazo (4 años) en términos de morbilidad y mortalidad no son mayores que los observados en la cirugía con puentes venosos de safena; c) es posible realizar una revascularización coronaria completa con conductos arteriales, aun en pacientes con función ventricular deprimida, y d) se pueden emplear conductos arteriales en pacientes añosos (AU)

Mercados financieros departamentales: Beni

Contenido: 1. Contexto agroecológico, económico y social 2. Sistema de comercialización 3. Economía rural: características básicas de la Unidad Económica Familiar Rural 4. Sistema financiero departamental 5. Análisis del sistema financiero 6. Demanda potencial para servicios financieros...

Mercados financieros departamentales: Santa Cruz

Contenido: 1. Contexto agroecológico, económico y social 2. Sistema de comercialización 3. Economía rural: características básicas de la Unidad Económica Familiar Rural 4. Flujo de caja en la economía rural 5. Estructura de costos de producción y formas de financiamiento 6. Necesidades reproductivas y formas de financiamiento 7. Visión Global del uso de crédito 8. Formas actuales de manejo de excedentes monetarios...