Differences in the degree of inhibition of NDP reductase by chemical inactivation and by the thermosensitive mutation nrdA101 in Escherichia coli suggest an effect on chromosome segregation.

NDP reductase activity can be inhibited either by treatment with hydroxyurea or by incubation of an nrdAts mutant strain at the non-permissive temperature. Both methods inhibit replication, but experiments on these two types of inhibition yielded very different results. The chemical treatment immediately inhibited DNA synthesis but did not affect the cell and nucleoid appearance, while the incubation of an nrdA101 mutant strain at the nonpermissive temperature inhibited DNA synthesis after more than 50 min, and resulted in aberrant chromosome segregation, long filaments, and a high frequency of anucleate cells. These phenotypes are not induced by SOS. In view of these results, we suggest there is an indirect relationship between NDP reductase and the chromosome segregation machinery through the maintenance of the proposed replication hyperstructure.post-print734 K

Relationship between Fork Progression and Initiation of Chromosome Replication in E. coli

post-print687 K

Spatial and temporal variation in the population density of the gold-ringed tanager (Bangsia Aureocincta : Thraupidae), endemic and vulnerable species of Colombia, in the Tatama national natural park.

Para conocer el estado de conservación de una especie es necesario determinar su abundancia y el cambio de ésta en el tiempo a través de programas rigurosos de monitoreo. Especialmente, cuando esta especie ha sido seleccionada como objeto de conservación de las áreas protegidas, su monitoreo se convierte en la herramienta de base para evaluar la efectividad del manejo. La bangsia del Tatamá (Bangsia aureocincta) se seleccionó como valor objeto de conservación –VOC– del Parque Nacional Natural Tatamá –PNN Tatamá–; este parque representa la integridad ecológica de la confluencia Andino-Pacífica en esta zona. Para conocer su estado de conservación y tendencia, se estimó la densidad poblacional usando el método de muestreo por distancia con puntos de conteo, en dos localidades separadas por 50 km lineales con una réplica temporal en 2016 y otra en 2018. Las densidades estimadas en 2016 fueron de 152 individuos/km2 (IC95% = 84 - 272; CV= 29,99) y 1036 individuos/ km2 (IC95% = 745 - 1442, CV= 16,82) y para 2018 de 341 individuos/km2 (IC95% = 213 - 547; CV= 23,96) y de 118 individuos/km2 (IC95% = 78 - 181, CV= 21,4). Estos resultados reflejan variaciones espaciales y temporales en la densidad de la especie que probablemente sean producto de migraciones longitudinales o altitudinales. No obstante, ante la falta de conocimiento de la historia natural de la especie, no es posible asociar estos movimientos a algún factor en particular.To know the conservation status of a species it is necessary to determine its abundance and the trends in a framework of rigorous monitoring program. Furthermore, when these species are the conservation target of the conservation strategies as protected areas, their monitoring is the way to assess the effectivity of the management. Bangsia del Tatama (Bangsia aureocincta) was chosen as a conservation target of the Tatama National Natural Park and it represents the ecological integrity of the Andino-Pacific confluence in this zone. To know its conservation status, we evaluate the population density using distance sampling method with point transect in two localities separated by 50 lineal kilometers with a temporal replica in 2016 and other in 2018. The population density found were in 2016 of 152 individuals/km2  (IC95% = 84 - 272; CV= 29,99) and 1036 individuals /km2 (IC95% = 745 - 1442, CV= 16.82), and to 2018 of 341 individuals /km2 (IC95% = 213 - 547; CV= 23.96) and 118 individuals/ km2 (IC95% = 78 - 181, CV= 21.4). These results show spatial and temporal variations in the density of the species, probably by longitudinal or altitudinal migrations. However, there is not enough knowledge of the natural history of the species to relate these movements to some factor

Flavonoid and Capsaicinoid Contents and Consumption of Mexican Chili Pepper (Capsicum annuum L.) Landraces

There is insufficient evidence to identify the precise health effects of chili pepper consumption. However, there is evidence of their topical use as an analgesic to decrease pain from rheumatoid arthritis, osteoarthritis, neuralgias, neuropathic diabetes, neuronal dysfunctions and inflammation, among others. In this work, the diversity and variety of consumed forms of chilis in Mexico, flavonoid and capsaicinoid content in fruits, and their potential health uses are documented, based on various research results and bibliographic information. In Mexico, more than 150 landraces of wild and cultivated origins are consumed and preserved and are distributed throughout the country; the greatest diversity is concentrated in the central and south-southeastern regions. Consumption per capita in urban households is from 8 to 9 kg, and in rural communities, it varies from 14 to 17 kg. Chili peppers contain up to 23 flavonoids and 20 capsaicinoids, differing among landraces because of crop management, maturation of fruits, postharvest management and ecological-environmental influences. Flavonoids and capsaicinoids confer antioxidant, anticarcinogenic properties on the fruit and have lipolytic and preventative effects on chronic degenerative diseases. However, in vitro and in vivo experimental trials of capsaicinoids and flavonoids with beneficial effects must be conducted with regard to human health

Diversity of Common Bean (Phaseolus vulgaris L.) Landraces and the Nutritional Value of their Grains

Grain legumes are considered major sources of dietary proteins, calories, certain minerals and vitamins, and they are the most widely cultivated and consumed crops worldwide. Among them are the common beans, whose major production volumes came from landraces cultivated in traditional farming systems. The objective of this study was to evaluate the phenotypic diversity of a set of common bean landraces from Mexico based on the agromorphological traits and nutritional composition of the grain in the context of traditional farming systems. Different field and laboratory data were collected and complemented with secondary information published in refereed journals and research reports. The results showed that there are significant differences in the morphological and physiological traits of the plant, pod and grain among groups of common bean landraces of different geographic origins, which were associated with different indigenous groups. Similar patterns were observed in the contents of anthocyanins, polyphenols, flavoinds and minerals as well as antioxidant activity. In the evaluated population groups in each region, there are outstanding populations in terms of agromorphological traits and the nutritional value of the grain that can enable a participatory breeding initiative guided by regional objectives. Some populations from Sierra Norte, Oaxaca, presented higher values in Zn and Fe, and populations from Estado de Mexico exhibited high polyphenol and flavonoid values but stable agronomic behaviour

Caribbean Corals in Crisis: Record Thermal Stress, Bleaching, and Mortality in 2005

BACKGROUND The rising temperature of the world's oceans has become a major threat to coral reefs globally as the severity and frequency of mass coral bleaching and mortality events increase. In 2005, high ocean temperatures in the tropical Atlantic and Caribbean resulted in the most severe bleaching event ever recorded in the basin. METHODOLOGY/PRINCIPAL FINDINGS Satellite-based tools provided warnings for coral reef managers and scientists, guiding both the timing and location of researchers' field observations as anomalously warm conditions developed and spread across the greater Caribbean region from June to October 2005. Field surveys of bleaching and mortality exceeded prior efforts in detail and extent, and provided a new standard for documenting the effects of bleaching and for testing nowcast and forecast products. Collaborators from 22 countries undertook the most comprehensive documentation of basin-scale bleaching to date and found that over 80% of corals bleached and over 40% died at many sites. The most severe bleaching coincided with waters nearest a western Atlantic warm pool that was centered off the northern end of the Lesser Antilles. CONCLUSIONS/SIGNIFICANCE Thermal stress during the 2005 event exceeded any observed from the Caribbean in the prior 20 years, and regionally-averaged temperatures were the warmest in over 150 years. Comparison of satellite data against field surveys demonstrated a significant predictive relationship between accumulated heat stress (measured using NOAA Coral Reef Watch's Degree Heating Weeks) and bleaching intensity. This severe, widespread bleaching and mortality will undoubtedly have long-term consequences for reef ecosystems and suggests a troubled future for tropical marine ecosystems under a warming climate.This work was partially supported by salaries from the NOAA Coral Reef Conservation Program to the NOAA Coral Reef Conservation Program authors. NOAA provided funding to Caribbean ReefCheck investigators to undertake surveys of bleaching and mortality. Otherwise, no funding from outside authors' institutions was necessary for the undertaking of this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Comparative serology techniques for the diagnosis of Trypanosoma cruzi infection in a rural population from the state of Querétaro, Mexico

Immunological diagnostic methods for Trypanosoma cruzi depend specifically on the presence of antibodies and parasitological methods lack sensitivity during the chronic and “indeterminate” stages of the disease. This study performed a serological survey of 1,033 subjects from 52 rural communities in 12 of the 18 municipalities in the state of Querétaro, Mexico. We detected anti-T. cruzi antibodies using the following tests: indirect haemagglutination assay (IHA), indirect immunofluorescence assay (IFA), ELISA and recombinant ELISA (rELISA). We also performed Western blot (WB) analysis using iron superoxide dismutase (FeSOD), a detoxifying enzyme excreted by the parasite, as the antigen. Positive test results were distributed as follows: ELISA 8%, rELISA 6.2%, IFA and IHA 5.4% in both cases and FeSOD 8%. A comparative study of the five tests was undertaken. Sensitivity levels, specificity, positive and negative predictive values, concordance percentage and kappa index were considered. Living with animals, trips to other communities, gender, age, type of housing and symptomatology at the time of the survey were statistically analysed using SPSS software v.11.5. Detection of the FeSOD enzyme that was secreted by the parasite and used as an antigenic fraction in WBs showed a 100% correlation with traditional ELISA tests

Sperm chromatin dispersion by formaldehyde in Wistar rats

Formaldehyde (FA) is an environmental xenobiotic, which is genotoxic and carcinogenic to humans and animals; it induces DNA damage, mutations, and clastogenicity during critical cytogenetic events. FA-mediated oxidative stress is an important mechanism that has been associated with the induction of cytotoxic and genotoxic damage. Therefore, the objective of this study was to evaluate the dispersion of sperm chromatin and reproductive parameters induced by exposure to different concentrations of FA in Wistar rats. Compared to the percentage of sperm with fragmented DNA in the control group (18.10 ± 8.62%), the percentage of sperm with fragmented DNA increased following exposure to 5, 10, and 30 mg FA/kg body weight (29.60 ± 8.44, 85.20 ± 20.94 and 96.0 ± 7.87, respectively; P = 0.0001). Histopathological alterations were evident, especially in the seminiferous tubules. In conclusion, this study provides experimental evidence concerning the genotoxicity of FA, with particular reference to the decreased sperm concentration and motility and increased dispersion of DNA chromatin in rats