The prevalence of multidrug-resistant Salmonella in raw shrimp and octopus in Campeche, Mexico

Introduction: Multidrug-resistant (MDR) pathogenic bacteria in seafood, especially shrimp and octopus, are significant public health concerns and are able to be transmitted to humans in foodstuffs, particularly when they are of animal origin. The present study was conducted to measure the antimicrobial susceptibility patterns and prevalence of Salmonella isolates obtained from octopus and shrimp in San Francisco de Campeche, Mexico. Methods: Two hundred shrimp and octopus samples (one hundred each) were collected from the municipal market, and each sample consisted of 100 g. The present study used conventional methods to identify and isolate Salmonella, with the disk-diffusion method used to screen all isolates for sensitivity to 12 antibiotics. Results: The prevalence of Salmonella was found to be 56% and 45% in shrimp and octopus, respectively. The high levels of Salmonella observed in the municipal market sampled by the present study reveal poor sanitary conditions in the processing and transport of the products of interest and those handling them at the point of sale. All the Salmonella strains were resistant to at least three antimicrobial classes. All shrimp isolates (100%) presented susceptibility to chloramphenicol and the majority (88%) presented sensitivity to ciprofloxacin, while the strains isolated in the octopus individuals sampled presented sensitivity to both the foregoing antibiotics (74% and 90%, respectively). Conclusion: Based on the high prevalence in the samples analyzed, our results suggest that shrimp and octopus could be involved in Salmonella infections in the population

Viviparidad en Echinocactus platyacanthus en el Altiplano Potosino y su posible beneficio para las etapas iniciales de desarrollo.

Tesis (Maestría en Ciencias Ambientales)"La viviparidad es un mecanismo reproductivo en el cual el embrión germina y emerge de los tejidos de la semilla antes de que sea liberada o dispersada. Este fenómeno es un evento raro en la naturaleza y se encontró en baja proporción en E. platyacanthus, por lo que no se pudo realizar la comparación del crecimiento de plántulas vivíparas (germinadas dentro del fruto) con el de plántulas germinadas en el suelo. Sin embargo; se evaluó si las semillas de frutos vivíparos y no vivíparos tienen diferente capacidad para germinar y desarrollar sus plántulas. Específicamente, el objetivo de este trabajo fue determinar las ventajas que ofrece la viviparidad en E. platyacanthus para la germinación de semillas y el desarrollo de las plántulas. Se llevaron a cabo recorridos por la mayor parte del Altiplano Potosino en el verano del 2010 en busca de poblaciones con individuos en etapa reproductiva de este cacto y se evaluó la incidencia de viviparidad. Se realizaron análisis físico-químicos en muestras de suelo tanto de plantas vivíparas como de no vivíparas. Se llevaron a cabo pruebas de viabilidad, así como de germinación con diferentes potenciales osmóticos (Ψo: 0, -0.2, -0.4, -0.6, -0.8 y -1.0 MPa), en semillas vivíparas (V-V), no vivíparas (N-V) y no vivíparas-vivíparas (N-V-V). También se evaluaron los niveles de ABA (inhibidor de la germinación) y AG3 (promotor germinativo) en semillas de las tres categorías. Finalmente, se realizaron curvas de luz para evaluar la eficiencia fotosintética de las plántulas provenientes de los tres tipos de semillas anteriormente mencionados. Se encontraron cuatro plantas con viviparidad de 44 plantas totales, con 41 frutos vivíparos de 262 colectados en dos poblaciones (Vanegas y Guadalcázar, S.L.P.). Sin embargo; no se encontraron diferencias aparentes en ninguna de las variables edáficas evaluadas entre plantas vivíparas y no vivíparas.""The vivipary is a reproductive mechanism in which the embryo has no dormancy and emerges from the tissues of the seed before it is released or dispersed by the maternal plant. This phenomenon is rare in the plant kingdom and it had low incidence in Echinocactus platyacanthus; thus, the comparison between viviparous and non-viviparous seedling growth was not realized. However, it was evaluated if seeds from viviparous and non-viviparous fruits have different ability to germinate and develop their seedlings. The aim of this study was to determinate the benefits of vivipary in Echinocactus platyacanthus for seed germination and seedling development. A search was conducted at the Altiplano Potosino in the summer of 2010 in search of populations with reproductive E. platyacanthus. The incidence of vivipary was determined. We conducted physical-chemical analysis of soil samples of with viviparous and non-viviparous plants. In addition, viability tests were conducted, as well as germination with different osmotic potentials (Ψo: 0, -0.2, - 0.4, -0.6, -0.8 and -1.0 MPa), in viviparous (V-V), non-viviparous-viviparous (N-VV) and non-viviparous (N-V) seeds. We also evaluated the ABA (germination inhibitor) and AG3 (germination promoter) levels in seeds of the three categories. Light curves were conducted to assess the photosynthetic efficiency of seedlings from the three seed categories. There were four viviparous plants out of 44 plants, with 41 viviparous fruits out of 262 collected in two populations (Vanegas and Guadalcázar, S.L.P.). No apparent differences in any of the soil variables evaluated between plants with and without viviparous seedlings were found.

Induced climate change impairs photosynthetic performance in Echinocactus platyacanthus, an especially protected Mexican cactus species

"The responses of desert plants to climate warming have been poorly assessed, perhaps due to the overall expectation that desert vegetation will expand as a consequence of this component of climate change. However, determining what plant species will tolerate the expected increase in temperature is a question that remains unanswered. The Chihuahuan Desert is the largest warm desert of North America, and predictive models of climate change indicate that summer temperatures in this desert will increase by 1–2 °C in the next decade. This study experimentally assessed the performance of an endangered cacti species from the Chihuahuan Desert under simulated warming conditions. Hexagonal open top-chambers (OTCs) were used to simulate the effects of global warming on five-years-old individuals of the specially protected species Echinocactus platyacanthus. Temperature was 1.9 °C higher in open top-chambers than in control plots. In contrast, relative humidity was 3.1% higher in control plots than in open top-chambers. E. platyacanthus showed 100% survival for 14 weeks in both OTC and control plots. However, induced warming negatively affected the photosynthetic performance of this species. Cacti located within OTCs displayed lower maximum quantum efficiency of photosystem II (Fv/Fm), effective quantum yield of photosystem II (?PSII), and electron transport rate (ETR) values, but higher non-photochemical quenching (NPQ) values, than cacti from control plots. This is the first study focused on the potential impact of climate warming on survival and photosynthetic performance of young individuals of a succulent species from American deserts. Induced warming negatively affected the photosynthetic performance of young E. platyacanthus, but it also increased non-photochemical quenching, a mechanism for avoiding photoinhibition.

Pre-Germinative Treatments and Morphophysiological Traits in Enterolobium cyclocarpum and Piscidia piscipula (Fabaceae) from the Yucatan Peninsula, Mexico

Enterolobium cyclocarpum and Piscidia piscipula are two important tree Fabaceae species distributed from the Yucatan Peninsula, Mexico. Our aims were focused on the E. cyclocarpum and P. piscipula seeds for: (1) to examine the seed permeability and imbibition rate, (2) to evaluate the effect of seed pre-germinative treatments, and (3) to characterize the structures involved on the presence of physical dormancy (PY). We used fresh seeds to determine seed permeability and imbibition rate, seed viability by means of tetrazolium test, furthermore, we applied mechanical scarification and boiler shocks for 5 s, 10 s and 15 s treatments. Morphological characterization of the seed coat was by Scanning Electron Microscope (SEM). Seed viability in E. cyclocarpum and P. piscipula were 100% and 96%, respectively. Seed permeability and imbibition rate in E. cyclocarpum were low. The highest germination in E. cyclocarpum was in the mechanical scarification (92%), while in P. piscipula, this parameter was in the 10 s boiling water treatment (76.0%). The presence of PY was confirmed in both species because they showed low seed permeability, and imbibition rate; furthermore, exhibited macrosclereids cells. The present research seeks to promote the sustainable use of E. cyclocarpum and P. piscipula