METRIZACIONES Y ALGUNAS PROPIEDADES DE LA TOPOLOGÍA DE FÜRSTENBERG

  Fürstenberg (Acevedo, 2002) defined a particular topology ? on the ring of integer numbers to give a beautiful proof of the infinitude of the prime numbers. Fürstenberg too indicated that the topological space (Z ?) is metrizable. The aim of this work is to examine the known metrizations of the Fürstenberg’s space and establish some results about it.Fürstenberg, (Acevedo, 2002) definió una particular topología ? sobre el anillo de los números enteros ? que le permitió dar una hermosa prueba de la infinitud de los números primos. Fürstenberg también señaló que el espacio topológico (?,?) es metrizable. Nuestro objetivo es examinar las metrizaciones conocidas del espacio de Fürstenberg y establecer algunos resultados al respecto

Hydric behaviour and gas exchange in different grapevine varieties (Vitis vinifera L.) from the Maule Valley (Chile)

In the near future, stomatal behaviour will be crucial to counteract conditions arising from climate change.  Grapevine varieties are classified as either isohydric or anisohydric, depending on the sensitivity of stomatato water deficit and on their water potential homeostasis. However, the great variability observed in different studies indicates that a continuum exists in the range of stomatal sensitivity to water stress. Thus, more knowledge about the hydric behaviour and the gas exchange of isohydric and anisohydric grapevine varieties under different water conditions could lead to the development of irrigation strategies oriented at improving water-use efficiency, yield and berry composition. In this study, research was conducted in order to characterise the stomatal regulation of four different Vitis vinifera L. varieties, namely Pinot noir, Sauvignon blanc, Chardonnay and Merlot, according to soil water status. Measurements of leaf gas exchange, together with measurements of stem water potential (Ψs) and leaf water potential (Ψl), were taken during two seasons. Under conditions of water stress, Chardonnay and Merlot reached a minimum Ψs of -1.67 and -1.68 MPa respectively, and higher levels of water-use efficiency (AN/gs), of 62.3 and 69.7 μmol CO2/mol H2O respectively. In Sauvignon blanc and Pinot noir, the minimum Ψs was -1.26 and -1.40 MParespectively, with lower levels of AN/gs (53.1 and 50.5 μmol CO2/mol H2O, respectively). Under conditions of water stress (Ψl < -0.9 MPa and Ψs < -0.6 MPa), all varieties had a significantly increased AN/gs1, despitea significant reduction in gas exchange. Therefore, the hydric behaviour and gas exchange observed in this study suggest that Chardonnay and Merlot could be characterised as anisohydric varieties, as they present less sensitive stomatal control, while Pinot noir can be classified as a near-anisohydric variety and Sauvignon blanc as an isohydric variety. New investigations should consider other characteristics of the varieties to classify them better

Mycobacterium tuberculosis in vivo-expressed genes detection during active pulmonary tuberculosis

Indexación: Web of Science; ScieloEl estudio de la expresión génica de Mycobacterium tuberculosis ha involucrado la experimentación "in vitro ", "ex vivo " e "in vivo " (modelos animales), pero aún sin el éxito esperado. Proponemos que revelar los factores clave de la tuberculosis humana requiere investigar la expresión génica de M. tuberculosis dentro del ser humano ("in vivo "). Para ello, aislamos el mRNA total de M. tuberculosis, desde muestras clínicas respiratorias de pacientes con diagnóstico de tuberculosis pulmonar; posteriormente, sintetizamos el dscDNA y lo analizamos mediante RT-PCR cualitativo. Detectamos la expresión de la secuencia de inserción IS6110 y de los genes "housekeeping " 16SrRNA y sigA en M. tuberculosis creciendo in vivo (tuberculosis pulmonar) así como cultivado in vitro. La expresión de los genes mprA y mprB, que codifican el sistema de transducción de señales MprAB, sólo se detectó en M. tuberculosis crecido in vitro. Con nuestros resultados damos el primer paso hacia la implementación de un método no invasivo para el estudio del transcriptoma de M. tuberculosis, dentro de su único hospedero natural, con el fin de analizar la regulación "in vivo" de los determinantes genéticos requeridos para su virulencia y patogénesis.Mycobacterium tuberculosis gene expression studies have involved "in vitro", "ex vivo" and "in vivo" experiments (animal models), but without the expected success. We propose that key features of human tuberculosis could be discovered by studying the M. tuberculosis gene expression within the human host. Therefore, we isolated totalM. tuberculosis mRNA from human clinical respiratory specimens of patients diagnosed with pulmonary tuberculosis; after this, we synthesized the dscDNA and tested it by qualitative RT-PCR assays. We detected the expression of IS6110 insertion sequence and of the "housekeeping" genes 16SrRNA andsigA in M. tuberculosis grown in vivo (pulmonary tuberculosis) as well as grown in vitro M. tuberculosis. mprA and mprB genes expression, which code the MprAB signal transduction system, were only detected in M. tuberculosis grown in vitro. Our results provide the first step towards a non invasive methodfor the study of the transcriptome of M. tuberculosis within its native host, to analyze "in vivo" regulation of the genetic determinants required for virulence and pathogenesis.http://www.scielo.cl/pdf/rcher/v28n4/art04.pd

The diving behaviour of mammal-eating killer whales (Orcinus orca): variations with ecological not physiological factors

Mammal-eating killer whales (Orcinus orca (L., 1758)) are a rare example of social predators that hunt together in groups of sexually dimorphic adults and juveniles with diverse physiological diving capacities. Day–night ecological differences should also affect diving as their prey show diel variation in activity and mammal-eating killer whales do not rely on echolocation for prey detection. Our objective was to explore the extent to which physiological aerobic capacities versus ecological factors shape the diving behaviour of this breath-hold diver. We used suction-cup-attached depth recorders (Dtags) to record 7608 dives of 11 animals in southeast Alaska. Analysis of dive sequences revealed a strong bout structure in both dive depth and duration. Day–night comparisons revealed reduced rates of deep dives, longer shallow dives, and shallower long-duration dives at night. In contrast, dive variables did not differ by age–sex class. Estimates of the aerobic dive limit (cADL) suggest that juveniles exceeded their cADL during as much as 15% of long dives, whereas adult males and females never exceeded their cADL. Mammal-eating killer whales in this area appear to employ a strategy of physiological compromise, with smaller group members diving nearer their physiological limits and large-bodied males scaling down their physiological performance

The effect of a startle-eliciting device on the foraging success of individual harbor seals (Phoca vitulina)

Pinniped predation on commercially and ecologically important prey has been a source of conflict for centuries. In the Salish Sea, harbor seals (Phoca vitulina) are suspected of impeding the recovery of culturally and ecologically critical Pacific salmon (Oncorhynchus spp.). In Fall 2020, a novel deterrent called Targeted Acoustic Startle Technology (TAST) was deployed at Whatcom Creek to deter harbor seals from preying on fall runs of hatchery chum (O. keta) and Chinook (O. tshawytscha) salmon in Bellingham, Washington, USA. Field observations were conducted in 2020 to compare the presence and foraging success of individual harbor seals across sound exposure (TAST-on) and control (TAST-off) conditions. Observations conducted the previous (2019) and following (2021) years were used to compare the effects observed in 2020 to two control years. Using photo-identification, individual seals were associated with foraging successes across all 3 years of the study. Generalized linear mixed models showed a significant 45.6% reduction in the duration (min) individuals remained at the creek with TAST on, and a significant 43.8% reduction in the overall foraging success of individuals. However, the observed effect of TAST varied across individual seals. Seals that were observed regularly within one season were more likely to return the year after, regardless of TAST treatment. Generalized linear models showed interannual variation in the number of seals present and salmon consumed. However, the effect of TAST in 2020 was greater than the observed variation across years. Our analyses suggest TAST can be an effective tool for managing pinniped predation, although alternate strategies such as deploying TAST longer-term and using multi-unit setups to increase coverage could help strengthen its effects. Future studies should further examine the individual variability found in this study.Peer reviewe

Large-scale antibody immune response mapping of splenic B cells and bone marrow plasma cells in a transgenic mouse model

Molecular characterization of antibody immunity and human antibody discovery is mainly carried out using peripheral memory B cells, and occasionally plasmablasts, that express B cell receptors (BCRs) on their cell surface. Despite the importance of plasma cells (PCs) as the dominant source of circulating antibodies in serum, PCs are rarely utilized because they do not express surface BCRs and cannot be analyzed using antigen-based fluorescence-activated cell sorting. Here, we studied the antibodies encoded by the entire mature B cell populations, including PCs, and compared the antibody repertoires of bone marrow and spleen compartments elicited by immunization in a human immunoglobulin transgenic mouse strain. To circumvent prior technical limitations for analysis of plasma cells, we applied single-cell antibody heavy and light chain gene capture from the entire mature B cell repertoires followed by yeast display functional analysis using a cytokine as a model immunogen. We performed affinity-based sorting of antibody yeast display libraries and large-scale next-generation sequencing analyses to follow antibody lineage performance, with experimental validation of 76 monoclonal antibodies against the cytokine antigen that identified three antibodies with exquisite double-digit picomolar binding affinity. We observed that spleen B cell populations generated higher affinity antibodies compared to bone marrow PCs and that antigen-specific splenic B cells had higher average levels of somatic hypermutation. A degree of clonal overlap was also observed between bone marrow and spleen antibody repertoires, indicating common origins of certain clones across lymphoid compartments. These data demonstrate a new capacity to functionally analyze antigen-specific B cell populations of different lymphoid organs, including PCs, for high-affinity antibody discovery and detailed fundamental studies of antibody immunity

Citotoxicidad/Capacidad antiradicalaria in-vitro y caracterización estructural por GC-MS/1H-13C-RMN de los aceites esenciales de hojas de árboles joven/adulto de Annona purpurea Moc. & Sessé ex Dunal de Repelón (Atlántico, Colombia)

Annona purpurea es una planta empleada en etnomedicina, en la región norte de Colombia, que no tiene reportes científicos relacionados con la composición de su AE y sus actividades biológicas. En este trabajo, los AE de hojas de árboles joven/adulto se caracterizaron por GC-MS y RMN y se evaluaron sus propiedades antiradicalarias/citotóxicas. Los AE de hojas de árboles joven/adulto estuvieron representados por β-eudesmol (68.9%) y α-eudesmol (16.8%), y germacreno D (55.6%) y biciclogermacreno (20.3%), respectivamente. El análisis por RMN mostró las señales distintivas de los constituyentes mayoritarios identificados. Los valores de TAA (mmol Trolox®/kg SE) obtenidos por los AE de árboles joven/adulto fueron 165 ± 8 y 602 ± 38. Los AE de árboles joven/adulto evaluados sobre linfocitos humanos fueron “moderadamente tóxicos” con valores de CL50 (μg/mL) de 145.5 ± 0.7 y 346 ± 8. Finalmente, la citotoxicidad en eritrocitos humanos reveló que el AE de árbol adulto no fue hemolítico (CL50 > 1000 μg/mL, 4.3 ± 0.6%); mientras que, el AE de árbol joven fue hemolítico (CL50 490 ± 48 μg/mL)

Influence of environmental parameters on movements and habitat utilization of humpback whales (Megaptera novaeangliae) in the Madagascar breeding ground

© The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Royal Society Open Science 3 (2016): 160616, doi:10.1098/rsos.160616.Assessing the movement patterns and key habitat features of breeding humpback whales is a prerequisite for the conservation management of this philopatric species. To investigate the interactions between humpback whale movements and environmental conditions off Madagascar, we deployed 25 satellite tags in the northeast and southwest coast of Madagascar. For each recorded position, we collated estimates of environmental variables and computed two behavioural metrics: behavioural state of ‘transiting’ (consistent/directional) versus ‘localized’ (variable/non-directional), and active swimming speed (i.e. speed relative to the current). On coastal habitats (i.e. bathymetry < 200 m and in adjacent areas), females showed localized behaviour in deep waters (191 ± 20 m) and at large distances (14 ± 0.6 km) from shore, suggesting that their breeding habitat extends beyond the shallowest waters available close to the coastline. Males' active swimming speed decreased in shallow waters, but environmental parameters did not influence their likelihood to exhibit localized movements, which was probably dominated by social factors instead. In oceanic habitats, both males and females showed localized behaviours in shallow waters and favoured high chlorophyll-a concentrations. Active swimming speed accounts for a large proportion of observed movement speed; however, breeding humpback whales probably exploit prevailing ocean currents to maximize displacement. This study provides evidence that coastal areas, generally subject to strong human pressure, remain the core habitat of humpback whales off Madagascar. Our results expand the knowledge of humpback whale habitat use in oceanic habitat and response to variability of environmental factors such as oceanic current and chlorophyll level.Funding was provided by Total Foundation to NeuroPSI, and by individuals and foundations to the WCS Ocean Giants Program

Cinco especies vegetales antiinflamatorias del Libellus de Medicinalibus Indorum Herbis de México, 1552: Una revisión botánica, química y farmacológica

Background and Aims: The Libellus de Medicinalibus Indorum Herbis (Little Book of the Medicinal Herbs of the Indians) includes 185 beautifully illustrated plants, 131 interpreted to species. Only some have been investigated regarding their attributed properties. Therefore, we selected six plants used as anti-inflammatories. The objectives of this work were to corroborate their botanical identity and to determine if contemporary chemical and pharmacological information supports their ancient therapeutic applications.Methods: The illustrations of the chosen plants were compared with specimens from the MEXU Herbarium to propose their possible taxonomic identity. The phytochemistry and anti-inflammatory activity of these species were reviewed in databases.Key results: The six plants selected from the Codex correspond to five species, since we consider that tetzmitl (Folium 13r) and texiyotl (Folium 22v) plants are the same species: Sedum dendroideum. Extracts from the leaves of S. dendroideum have shown anti-inflammatory activity in different pharmacological models due to derivatives of the flavonoid kaempferol, which supports its ancient medical applications to treat swollen face, eyes, and mouth. In Folium 48v, tzihuac copalli and tlacoecapatli are prescribed when “the vein punctured by the phlebotomy swells.” We agree they are Bursera bipinnata and Litsea glaucescens, respectively. To date, their possible anti-inflammatory properties have not been investigated, but other related species do present these. The Folium 22v recommends tememetla and tequixquiçacatl to relieve inflamed mouth. We corroborate that they are Echeveria gibbiflora and Distichlis spicata, respectively. These species do not have chemical-pharmacological studies.Conclusions: The bibliographic review suggests that anti-inflammatory properties attributed to S. dendroideum in the Codex have chemical and pharmacological support. Chemotaxonomic and pharmacological information suggests that B. bipinnata and L. glaucescens could bear these attributes and should be investigated experimentally. These three species are still used as anti-inflammatory in contemporary traditional medicine.Antecedentes y Objetivos: El Libellus de Medicinalibus Indorum Herbis (Librito de las Hierbas Medicinales de los Indios) incluye 185 plantas bellamente ilustradas, 131 interpretadas a especie. Solo algunas se han investigado respecto a las propiedades que ahí se les atribuyen. Por ello, seleccionamos seis plantas utilizadas como antiinflamatorias. Los objetivos de este trabajo fueron corroborar su identidad botánica y determinar si la información química y farmacológica contemporánea respalda sus antiguas aplicaciones terapéuticas.Métodos: Para proponer las especies a las cuales posiblemente corresponden las ilustraciones de las plantas elegidas, estas se compararon con especímenes del Herbario MEXU. Se revisó en bases de datos la fitoquímica y actividad antiinflamatoria de dichas especies.Resultados clave: Las seis plantas seleccionadas del códice corresponden a cinco especies, pues consideramos que las plantas tetzmitl (Folium 13r) y texiyotl (Folium 22v) son la misma especie: Sedum dendroideum. Los extractos de las hojas de S. dendroideum han presentado actividad antiinflamatoria en diferentes modelos farmacológicos debido a derivados del flavonoide kaempferol, lo cual respalda sus antiguas aplicaciones médicas para tratar la cara, ojos y boca hinchados. En el Folium 48v se prescriben tzihuac copalli y tlacoecapatli cuando “se hincha la vena pinchada por la flebotomía”. Concordamos en que son Bursera bipinnata y Litsea glaucescens, respectivamente. A la fecha, no se han investigado sus posibles propiedades antiinflamatorias, pero sí las presentan otras especies relacionadas. El Folium 22v recomienda tememetla y tequixquiçacatl para aliviar la boca inflamada. Corroboramos que son Echeveria gibbiflora y Distichlis spicata, respectivamente. Dichas especies no cuentan con estudios químico-farmacológicos.Conclusiones: La revisión bibliográfica sugiere que las propiedades antiinflamatorias atribuidas en el Códice para S. dendroideum tienen sustento químico y farmacológico. La información quimiotaxonómica y farmacológica sugiere que B. bipinnata y L. glaucescens podrían presentarlas y deben investigarse experimentalmente. Estas tres especies aún se emplean como antiinflamatorias en la medicina tradicional contemporánea

A Broad Assessment of Factors Determining Culicoides imicola Abundance: Modelling the Present and Forecasting Its Future in Climate Change Scenarios

Bluetongue (BT) is still present in Europe and the introduction of new serotypes from endemic areas in the African continent is a possible threat. Culicoides imicola remains one of the most relevant BT vectors in Spain and research on the environmental determinants driving its life cycle is key to preventing and controlling BT. Our aim was to improve our understanding of the biotic and abiotic determinants of C. imicola by modelling its present abundance, studying the spatial pattern of predicted abundance in relation to BT outbreaks, and investigating how the predicted current distribution and abundance patterns might change under future (2011–2040) scenarios of climate change according to the Intergovernmental Panel on Climate Change. C. imicola abundance data from the bluetongue national surveillance programme were modelled with spatial, topoclimatic, host and soil factors. The influence of these factors was further assessed by variation partitioning procedures. The predicted abundance of C. imicola was also projected to a future period. Variation partitioning demonstrated that the pure effect of host and topoclimate factors explained a high percentage (>80%) of the variation. The pure effect of soil followed in importance in explaining the abundance of C. imicola. A close link was confirmed between C. imicola abundance and BT outbreaks. To the best of our knowledge, this study is the first to consider wild and domestic hosts in predictive modelling for an arthropod vector. The main findings regarding the near future show that there is no evidence to suggest that there will be an important increase in the distribution range of C. imicola; this contrasts with an expected increase in abundance in the areas where it is already present in mainland Spain. What may be expected regarding the future scenario for orbiviruses in mainland Spain, is that higher predicted C. imicola abundance may significantly change the rate of transmission of orbiviruses