The agricultural drainage water from the Sinaloa valley (Mexico) is often reused in agriculture and aquaculture before reaching coastal water bodies. Discharged water must be of good quality to ...maintain the health of ecosystems and prevent damage to the organisms that compose them. This research determined the occurrence of coliforms in a drainage ditch known as La Michoacana (Sinaloa) that receives contaminated water from agricultural and urban sources. A section of 3.6 km was studied during 2013 and samples were obtained monthly from five equidistant sampling sites. Each water sample was analyzed for total coliform (TC) and fecal coliform (FC) content, pH, salinity, temperature, and dissolved oxygen percentage (%DO). The sampling sites with the highest bacterial contamination were associated with direct discharges of domestic wastewater and those with the lowest to the output drain. The performance of this agricultural ditch decreased the concentration of coliforms, with median and average values of 96% and 87% for TC, and 98% and 85% for FC, respectively. The most common bacteria were Escherichia coli (67.7%), Kluyvera cryocrescens (10.2%), and Enterobacter agglomerans (6.3%). Coliform concentration was positively correlated with temperature and negatively with %DO. The ditch improved the microbiological quality of the water, demonstrating remediation activities in the system. Proper management and maintenance of agricultural drainage ditches would favorably impact the health and biodiversity, as well as the intensive aquaculture and agricultural activities of the Sinaloa valley.
Methicillin-resistant Staphylococcus aureus (MRSA) is a human pathogen of great concern owing to its antimicrobial resistance and virulence properties. Here we report the first draft genome sequence ...of a mecA-negative community-associated MRSA strain isolated from a healthy young Mexican paediatric carrier in order to reveal the genomic structure underlying the multidrug-resistant phenotype and to discover the virulence properties of this strain.
The draft genome sequence of S. aureus L401 was obtained using an Ion Torrent™ PGM platform. De novo assembled contigs were annotated, and antimicrobial resistance genes and virulence factors were identified using ResFinder and VirulenceFinder, respectively. In addition, a mutational survey of native pbp, gdpP and yjbH genes was performed. In silico multilocus sequence typing (MLST) and spa typing were also performed.
S. aureus L401 has a genome size of 2 831 587 bp with 2799 protein-coding sequences. Various antimicrobial resistance genes conferring resistance to aminoglycosides, β-lactams, fluoroquinolones and macrolide–lincosamide–streptogramin B antimicrobials were found. Although both mecA and staphylococcal cassette chromosome mec (SCCmec) elements were absent, a missense mutation in PBP3 was identified. Moreover, genes encoding exfoliative toxin A, γ- and β-haemolysin, and several enterotoxins were also identified. S. aureus L401 belongs to ST109 and spa type t209.
The availability of this genome will allow an insight into S. aureus resistance and virulence determinants as well as its epidemiology, lineage, evolution and genomic features involved in the paediatric commensal carriage.
The molecular mechanism of the fungal tolerance phenotype to fungicides is not completely understood. This knowledge would allow for the development of environmentally friendly strategies for the ...control of fungal infection. With the goal of determining genes induced by 2p-ITC, a forward suppressive subtractive hybridization was performed using cDNAs from ITC-treated
Alternaria alternata as a “tester” and from untreated fungus as a “driver.” Using this approach, a library containing 102 ESTs was generated that resulted in 50 sequences after sequence assembly (17 contigs and 33 singletons). Blastx analysis revealed that 38% and 40% of the sequences showed significant similarity with known and hypothetical proteins, respectively, whereas 18% were not similar to known genes. These last sequences could represent novel genes that play an unknown role in the molecular responses of fungi during adaptation to 2p-ITC. Clones similar to opsins, ABC transporters, calmodulin, ATPases and SNOG proteins were identified. Using real-time RT-PCR analysis, significant inductions of an ABC transporter and a Ca
++ ATPase during 2p-ITC treatment were discovered. These results suggest that the fungal resistance phenotype to 2p-ITC involves calcium ions and 2p-ITC efflux via an ABC transporter.
We present here the first draft genome sequence of a typical enteropathogenic
serotype O55:H51 strain, M15-4, isolated from a 2-month-old infant girl with acute diarrhea. The study of this Mexican ...isolate will provide insights to the virulence and drug resistance traits involved in its pathogenic potential.
We report here the first draft genome sequence of a Mexican communitarian methicillin-resistant
(MRSE) strain whose genome harbors a wide variety of resistance determinants. The availability of this ...genome will allow the study of antibiotic resistance in Mexican staphylococci from a genomic perspective.
Course-based research pedagogy involves positioning students as contributors to authentic research projects as part of an engaging educational experience that promotes their learning and persistence ...in science. To develop a model for assessing and grading students engaged in this type of learning experience, the assessment aims and practices of a community of experienced course-based research instructors were collected and analyzed. This approach defines four aims of course-based research assessment—(1) Assessing Laboratory Work and Scientific Thinking; (2) Evaluating Mastery of Concepts, Quantitative Thinking and Skills; (3) Appraising Forms of Scientific Communication; and (4) Metacognition of Learning—along with a set of practices for each aim. These aims and practices of assessment were then integrated with previously developed models of course-based research instruction to reveal an assessment program in which instructors provide extensive feedback to support productive student engagement in research while grading those aspects of research that are necessary for the student to succeed. Assessment conducted in this way delicately balances the need to facilitate students’ ongoing research with the requirement of a final grade without undercutting the important aims of a CRE education.
El agua que conducen los canales de drenaje del valle agrícola sinaloense (México) es reutilizada con frecuencia en la agricultura y acuacultura antes de ser depositada en las aguas costeras. La ...calidad del agua descargada debe ser adecuada para mantener la salud de los ecosistemas y evitar daño a los organismos que los componen. Esta investigación determinó la presencia de coliformes en el canal de drenaje agrícola conocido como La Michoacana (Sinaloa), que recibe agua contaminada de fuentes agrícolas y urbanas. Se estudió una sección de 3.6 km del canal durante el año 2013 y se recolectaron mensualmente muestras de agua de cinco puntos de muestreo equidistantes. A cada muestra se le analizó el contenido de coliformes totales (CT) y coliformes fecales (CF), pH, salinidad, temperatura y porcentaje de saturación de oxígeno disuelto (%OD). Los puntos de muestreo con mayor contaminación bacteriana estuvieron asociados a las descargas directas de agua residual doméstica, y aquellos con menor contaminación estuvieron asociados a la salida del canal de drenaje. El funcionamiento del canal disminuyó la carga de coliformes, con medianas y valores promedio del 96% y 87% para CT, y 98% y 85% para CF, respectivamente. Las principales bacterias identificadas fueron Escherichia coli (67.7%), Kluyvera cryocrescens (10.2%) y Enterobacter agglomerans (6.3%). La concentración de coliformes presentó una correlación positiva con la temperatura y negativa con el %OD. El canal de drenaje La Michoacana mejora la calidad microbiológica del agua que conduce, lo cual demuestra funciones de remediación en el sistema. El mantenimiento y manejo adecuado de los canales de drenaje agrícola puede impactar favorablemente la salud y biodiversidad, así como las actividades acuícolas y agrícolas intensivas del valle sinaloense.
Los isotiocianatos son compuestos naturales con potente actividad antifúngica producidos por Brassicas como parte de su sistema de defensa. Estos compuestos representan una alternativa a la ...utilización de compuestos químicos para el control de infecciones fúngicas en productos agrícolas. El objetivo de la revisión fue analizar los estudios publicados acerca de los mecanismos moleculares de la respuesta de hongos al efecto tóxico de los isotiocianatos. Los estudios en Alternaria brassicicola demuestran la inducción de genes cuyos productos cumplen funciones en estrés oxidativo (citocromo P450, tioredoxinas y oxidoreductasas), así como en la excreción de isotiocianatos (glutatión-S-transferasas y transportadores ABC). El hongo A. brassicicola es un patógeno especializado en Brassicas, mientras que Alternaria alternata es un patógeno generalista. Sin embargo, en A. alternata también se reportó la inducción de un gen codificando a un transportador ABC. En base a los datos de la revisión se puede concluir que el mecanismo de respuesta a isotiocianatos en hongos incluye la formación de un conjugado isotiocianato-glutatión que es excretado mediante un transportador ABC. Se sugiere que la utilización de isotiocianatos en combinación con inhibidores de transportadores ABC, podría evitar la resistencia fúngica y constituiría un tratamiento amigable con el ambiente y la salud humana.
Tilapia is the most cultivated fish around the world. The fish’s environment can harbor bacteria, especially coliforms, which are not normal biota of fish. These microorganisms are contamination ...indicator groups (IGs) reflecting the possible presence of pathogens, which can compromise the safety of fishery products. The IGs prevalence was estimated in tilapia and water from 29 aquaculture farms. Total and fecal coliforms (TC, FC), mesophilic aerobic bacteria (MAB), S. aureus, E. coli, Salmonella sp., and Streptococcus sp., were investigated. In tilapia, TC and FC were detected in 64% and 48% of the samples, ranging from 4.0 x 101 to 9.8 x 105, and from 1.0 x 101 to 6.4 x 103 CFU/g, respectively; MAB were detected in 90% of the samples. In water, TC and FC were detected in 57% and 35% of the samples, oscillating from 1.0 x 101 to 2.28 x104, and from 1.0 x 101 to 1.2 x 103 CFU/mL, respectively. MAB were detected in 89% of the water samples. Mostly E. coli and Enterobacter agglomerans were detected. Generally, IGs concentrations meet the Mexican regulations; however, the tilapia’s microbiological quality must be continuously monitored.
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