Fourier transform infrared spectrometer analysis and antimicrobial screening of ethanolic extract of Operculina terpathum from cholistan desert

Aim of present study was to assess pharmacological (antioxidant, antibacterial & antifungal) potential of Operculina terpathum seeds. Ethanolic extract was prepared and its phytochemical evaluation show the different chemical compounds such as carbohydrates, phenols, tannin, flavonoids, cardiac glycosides, steroids, alkaloids and proteins. FTIR spectra showed the presence of organic acids, hydroxyl and phenolic compounds, amino groups, aliphatic compounds, functional groups such as amide, ketone, aldehyde, aromatics and halogen compounds. Antioxidant activity of the Operculina terpathum alcoholic extract was performed by DPPH method and it showed 97.13%whereas IC50±SEM (μg/ml) was 1.425±0.16. Antibacterial activity was performed against different bacterial strains and results were comparable with that of standard. Maximum antibacterial activity was exhibited by Bacillus subtillis (28.33±2 mm) and Bacillus pumilus (25.33±2 mm) respectively. Antifungal activity was also performed and it showed maximum activity against Aspergillus flavous and Candida albicans6±1, 5±1mm respectively. These results showed that Operculina terpathum has good antibacterial and antifungal activity against different microbes and it could be used as an alternative to antibiotics, as the antibiotics resistance is very common now a days. (AU)

Oxygen use in Atacama large millimeter and submillimeter (ALMA) arrays in Chajnantor valley at 5050 m / Uso de oxígeno en Atacama large millimeter and submillimeter (ALMA) en el valle de Chajnantor a 5050 m

The Chilean workforce has over 200,000 people that are intermittently exposed to altitudes over 4000 m. In 2012, the Ministry of Health provided a technical guide for high altitude workers that included a series of actions to mitigate the effects of hypoxia. Previous studies have shown the positive effect of oxygen enrichment at high altitudes. The Atacama Large Millimeter / submillimeter Arrays (ALMA) radiotelescope operate at 5,050 m (Array Operation Site, AOS) and is the only place in the world where Pressure Swing Adsorption (PSA) and Liquid Oxygen technologies have been installed at a large scale. Here we discuss our experience using oxygen supplementation at ALMA, to prevent the malaise and/or risks associated with exposure at 5,050 m. Antenna operators experienced chronic intermittent hypobaric hypoxia (CIHH, shiftwork 8 days HA*6 days rest SL) over 4 years. Studies to define normal O2 saturation values were performed in OSF and AOS by continuous recording during the shift. The outcomes showed no differences between production procedures (PSA or Liquid oxygen) in regulating oxygen availability at AOS facilities. As a result, big-scale installations have difficulties reaching the appropriate oxygen concentration due to leaks in high mobility areas. In addition, the PSA plant requires adequation and maintenance to operate at a very high altitude.

La fuerza laboral chilena cuenta con más de 200.000 personas que están expuestas intermitentemente a altitudes superiores a los 4000 m. En 2012, el Ministerio de Salud entregó una guía técnica para trabajadores de altura que incluía una serie de acciones para mitigar los efectos de la hipoxia. Estudios anteriores han demostrado el efecto positivo del enriquecimiento de oxígeno en altitudes elevadas. El radiotelescopio Atacama Large Millimeter/submillimeter Arrays (ALMA) opera a 5.050 m (Array Operation Site, AOS) y es el único lugar en el mundo donde se han instalado tecnologías de adsorción por cambio de presión (PSA) y oxígeno líquido a gran escala. Aquí discutimos nuestra experiencia usando suplementos de oxígeno en ALMA, para prevenir el malestar y/o los riesgos asociados con la exposición a 5.050 m. Los operadores de antena experimentaron hipoxia hipobárica intermitente crónica (CIHH, trabajo por turnos 8 días HA*6 días descanso SL) durante 4 años. Se realizaron estudios para definir valores normales de saturación de O2 en OSF y AOS mediante registro continuo durante el turno. Los resultados no mostraron diferencias entre los procedimientos de producción (PSA u oxígeno líquido) en la regulación de la disponibilidad de oxígeno en las instalaciones de AOS. Como resultado, las instalaciones a gran escala tienen dificultades para alcanzar la concentración de oxígeno adecuada debido a fugas en áreas de alta movilidad. Además, la planta de PSA requiere de adecuación y mantenimiento para operar a gran altura.

Partial purification, characterization and application of thermoalkaliphilic proteases from Priestia endophytica, Lysinibacillus cresolivorans and Bacillus subtilis isolated from desert soil

Aims@#Thermophilic proteases are important industrial enzymes because they can be used at high temperatures in various bioprocessing schemes. The bacterial population of the Cholistan desert was explored for thermophilic proteases and their industrial applications.@*Methodology and results@#Three bacterial isolates K1, K5 and K7 were found promising protease producers. These isolates were preliminary identified as Bacillus based on morphological characteristics and biochemical tests (positive for catalase, oxidase and citrate tests, and negative for indole and urease tests). The isolates K1, K5 and K7 were further identified as Priestia endophytica, Lysinibacillus cresolivorans and Bacillus subtilis, respectively by phylogenetic analysis. The isolates grew best at 50 °C and P. endophytica (K1), L. cresolivorans (K5) and B. subtilis (K7) produced larger zones of hydrolysis at 37 °C, 45 °C and 50 °C at pH 7, respectively. The optimum temperature where protease activity was maximum was 65 °C for P. endophytica and L. cresolivorans and 55 °C for B. subtilis, and the optimum pH was 9.@*Conclusion, significance and impact of study@#The proteases produced by these isolates were found active at high temperatures (45 °C to 85 °C) and high pH (9-12), which make them industrially important thermoalkaliphilic proteases. These proteases successfully de-haired cow’s skin and de-stained blood from cotton cloth pieces, which are rarely tested applications of these proteases.

Microorganismos xerófilos cultivables de la zona semiárida de la Tatacoa (Colombia) / Culture xerophile microorganisms from the Tatacoa semiarid zone (Colombia)

Resumen Introducción. Los microorganismos xerófilos han adquirido una mayor relevancia para la realización de investigaciones relacionadas con sus mecanismos adaptativos frente al estrés hídrico, así como la caracterización e identificación de sus hábitats. En Colombia, las zonas semiáridas y desérticas como el desierto de la Tatacoa han sido poco estudiadas a nivel microbiano. Objetivo. Aislar y caracterizar microorganismos xerófilos provenientes del suelo de la zona semiárida de la Tatacoa del departamento del Huila (Colombia). Materiales y métodos. Se colectaron muestras en los sectores denominados localmente como Cuzco y La Victoria, las cuales fueron procesadas para el aislamiento de microorganismos xerófilos en medio selectivo M40Y para posterior caracterización macro y microscópica, así como evaluación mediante pruebas bioquímicas para la utilización de sustratos. Resultados. Fueron aislados 29 morfotipos entre los cuales se pudieron diferenciar: Bacilos y cocos Gram positivos presentes exclusivamente en el sector del Cuzco y bacterias filamentosas ramificadas (actinobacterias) únicamente en el sector de La Victoria. Se estableció la presencia de los géneros Streptomyces, Micrococcus y Corynebacterium. Conclusiones. La presencia de microorganismos relacionados con los géneros anteriormente mencionados permitirá comprender las posibles interacciones que se presentan en este ecosistema, lo que aportará al desarrollo de este lugar como un posible análogo para estudios de búsqueda de vida en otros planetas como Marte. Además, incentivar estudios más detallados donde se puedan recuperar microorganismos que sean de utilidad para diferentes procesos biotecnológicos.

Abstract Introduction. Xerophilic microorganisms have become more relevant for conducting research related to their adaptive mechanisms against water stress, as well as the characterization and identification of their habitats. In Colombia, semi-arid and desert areas such as the Tatacoa desert have been little studied at the microbial level. Objective. Isolation and characterization of cultivable xerophilic microorganisms from the soil of the semi-arid zone of Tatacoa, in the department of Huila (Colombia). Material and methods. For this, samples were collected in the sectors locally called Cuzco and La Victoria, which were processed for the isolation of xerophilic microorganisms in selective M40Y medium for subsequent macro and microscopic characterization, as well as evaluation by biochemical tests for the use of substrates. Results. 29 morphotypes were isolated among which it was possible to differentiate: Gram-positive bacilli and cocci present exclusively in the Cuzco sector and branched filamentous bacteria (Actinobacteria) only in the La Victoria sector. The presence of the genera Streptomyces, Micrococcus and Corynebacterium was established. Conclusions. The presence of microorganisms related to the mentioned genera will allow us to understand the possible interactions that occur in this ecosystem, which will contribute to the development of this place as a possible analogue of studies for the search for life on other planets such as Mars. In addition, promote more detailed studies where microorganisms that are useful for different biotechnological processes can be recovered.

Phylogenetic relationships of plant species from the flowering desert of the Atacama Region / Relaciones filogenéticas de especies de plantas que crecen en el desierto florido de la Región de Atacama

Every 3 to 7 year angiosperms species of the flowering desert appear in the Atacama Region of Chile, as a result of the climatic phenomenon "El Niño". Our objective was to evaluate the universality of matK and rbcL barcode markers of these species, and validate their taxon through phylogenetic relationships. Argemone hunnemannii, Oenothera coquimbensis, Malesherbia humilis, Leucocoryne appendiculata, Loasa elongata, Nicotiana solanifolia, Stachys grandidentata, Aristolochia chilensis, Alstroemeria kingii and Adesmia eremophila, almost all classified as endemic to Chile, were collected in Pan de Azúcar and Llanos de Challe National Park (Atacama Region, Chile) at the end of October 2017. The phylogeny of these ten angiosperm species from the flowering desert was analyzed using rbcL and matK markers with the maximum likelihood and Bayesian inference methods. The results showed that 70% of the species can be distinguished with the matK or rbcL locus, however, 100% were distinguished using both loci. The phylogenetic results showed that the species formed clades with high reliability and high support with both the matK and rbcL genes, when comparing our results with sequences obtained from GenBank. The matK and rbcL genes are efficient markers for analyzing phylogenetic relationships and validating the taxonomy of flowering species.

Las especies de angiospermas del Desierto Florido de la Región de Atacama de Chile aparecen cada 3 a 7 años, influenciado por el fenómeno climático "El Niño". Nuestro objetivo fue evaluar la universalidad de los marcadores de código de barra matK y rbcL de estas especies, y validar su taxón por medio de relaciones filogenéticas. Las especies Argemone hunnemannii, Oenothera coquimbensis, Malesherbia humilis, Leucocoryne appendiculata, Loasa elongata, Nicotiana solanifolia, Stachys grandidentata, Aristolochia chilensis, Alstroemeria kingii y Adesmia eremophila son clasificadas la mayoría endémicas de Chile. Estas especies fueron colectadas en el Parque Nacional Pan de Azúcar y Llanos de Challe, Región de Atacama, Chile. La colecta se realizó a fines de octubre de 2017. Con los marcadores rbcL y matK se analizó la filogenia con los métodos máxima verosimilitud e inferencia bayesiana en diez especies de angiosperma del Desierto Florido. Los resultados mostraron que el 70% de las especies pueden ser distinguidas con un locus matK o rbcL, sin embargo, el 100% se distinguió usando ambos locus. Los resultados filogenéticos mostraron que las especies formaron clados con alta fiabilidad y alto soporte tanto con los genes matK y rbcL, al comparar con accesos de secuencias obtenidas de GenBank. Lo genes matK y rbcL son marcadores eficientes para analizar relaciones filogenéticas y validar el taxón de las especies de flor.

Polvo del Sáhara en el corazón de Europa / Sahara dust in the heart of Europe

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A whole-transcriptome approach to evaluate reference genes for quantitative diurnal gene expression studies under natural field conditions in Tamarix ramosissima leaves

Background: Tamarix ramosissima is a desert forest tree species that is widely distributed in the drought-stricken areas to sustain the fragile ecosystem. Owing to its wide usage in the desert restoration of Asia, it can be used as an ecophysiological model plant. To obtain reliable and accurate results, a set of reference genes should be screened before gene expression. However, up to date, systematical evaluation of reference genes has not been conducted in T. ramosissima. Results: In this study, we used eigenvalues derived from principal component analysis to identify stable expressed genes from 72,035 unigenes from diurnal transcriptomes under natural field conditions. With combined criteria of read counts above 900 and CV of FPKM below 0.3, a total of 7385 unigenes could be qualified as candidate reference genes in T. ramosissima. By using three statistical algorithm packages, geNorm, NormFinder, and BestKeeper, the stabilities of these novel reference genes were further compared with a panel of traditional reference genes. The expression patterns of three aquaporins (AQPs) suggested that at least UBQ (high expression), EIF4A2 (low expression), and GAPDH (moderate expression) could be qualified as ideal reference genes in both RT-PCR and RNA-seq analysis of T. ramosissima. Conclusions: This work will not only facilitate future studies on gene expression and functional analysis of genetic resources of desert plants but also improve our understanding of the molecular regulation of water transport in this plant, which could provide a new clue to further investigate the drought adaptation mechanism of desert plant species under harsh environments.

Ignimbrite textural properties as determinants of endolithic colonization patterns from hyper-arid Atacama Desert

This study explores the photosynthetic microbial colonization of rhyolitic ignimbrites in Lomas de Tilocalar, a hyper-arid region of the Atacama Desert, Chile. Colonization appeared in the form of a green layer a few millimeters beneath the ignimbrite surface. Some ignimbrite rocks revealed two distinct micromorphological areas of identical mineralogical and chemical composition but different textural properties. According to texture, colonization patterns varied in terms of the extension and depth of colonization. The diversity of photosynthetic microorganisms was assessed by denaturing gradient gel electrophoresis (DGGE) of the 23S rRNA gene and by generating clone libraries of the 16S rRNA gene. We observed a low diversity of photosynthetic microorganisms colonizing the ignimbrite microhabitat. Most rRNA gene sequences recovered greatly resembled those of Chroococcidiopsis hypolith clones from arid deserts. These results point to highly restrictive conditions of the hyper-arid Atacama Desert conditioning the diversity of cyanobacteria, and suggest that microbial colonization and composition patterns might be determined by the microscale physico-chemical properties of the ignimbrite rocks (AU)

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Microorganisms in desert rocks: the edge of life on Earth

This article reviews current knowledge on microbial communities inhabiting endolithic habitats in the arid and hyper-arid regions of our planet. In these extremely dry environments, the most common survival strategy is to colonize the interiors of rocks. This habitat provides thermal buffering, physical stability, and protection against incident UV radiation, excessive photosynthetically active radiation, and freeze-thaw events. Above all, through water retention in the rocks' network of pores and fissures, moisture is made available. Some authors have argued that dry environments pose the most extreme set of conditions faced by microorganisms. Microbial cells need to withstand the biochemical stresses created by the lack of water, along with temperature fluctuations and/or high salinity. In this review, we also address the variety of ways in which microorganisms deal with the lack of moisture in hyper-arid environments and point out the diversity of microorganisms that are able to cope with only the scarcest presence of water. Finally, we discuss the important clues to the history of life on Earth, and perhaps other places in our solar system, that have emerged from the study of extreme microbial ecosystems (AU)

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Desarrollo reproductivo del “amancay” Ismene amancaes (Amaryllidaceae) en su ambiente natural / Reproductive development of “amancay” Ismene amancaes (Amaryllidaceae) in its natural environment

Ismene amancaes “amancay” es una especie bulbosa característica de las formaciones vegetales denominadas “Lomas” de la costa central del Perú. Emerge al iniciar el periodo de neblina que ocurre en junio, durante el invierno. Presenta flores grandes amarillas y con agradable aroma, muy apreciadas y de valor ornamental. A fin de conocer el desarrollo reproductivo de Ismene amancaes en su ambiente natural se hicieron muestreos mensuales de sus bulbos durante todo un año. Se realizaron observaciones del interior del bulbo para determinar el inicio de la formación y desarrollo de las yemas florales y se relacionó con la formación de sus hojas y la humedad edáfica. Se puede indicar que las primeras yemas florales se hacen evidentes el año anterior a su emergencia, en el mes de diciembre, alcanzando el máximo número de yemas florales en febrero (periodo de verano). La diferenciación de las yemas florales se inicia luego de haberse formado las hojas que saldrán el siguiente año y en el periodo de máximo descenso de la humedad edáfica y de incremento de la temperatura (noviembre). La inflorescencia es la única ramificación que se forma mientras que la yema apical continua formando hojitas. En junio, la pequeña inflorescencia alcanza el cuello del bulbo y avanza seguido por las hojas formadas antes de la inflorescencia siendo envolventes a la inflorescencia misma y a la yema foliar apical. La yema foliar continuará su desarrollo y en julio dos de sus hojas salen del bulbo, las siguientes aun pequeñas quedan dentro y brotarán en el periodo de Lomas del siguiente año. Se puede señalar que el éxito reproductivo de Ismene amancaes en su etapa inicial es dependiente de los fotoasimilados acumulados como biomasa del bulbo en el periodo de Lomas anterior.

Ismene amancaes “amancay” is a bulbose species typical of the central coast vegetation of Peru called “lomas”. This species sprouts in June during the beginning of the winter-fog period. It has large yellow, aromatic flowers valued for their ornamental value. Our goal was to examine the reproductive development of Ismene amancaesin its natural environment, and we recorded monthly observations during a yearlong study. Observations of the interior of the bulbs allowed recording of the beginning of floral bud formation and development, relating them to leaf formation and edaphic humidity. We found that the first floral buds develop the year before their emergence in December, reaching a maximum number of floral buds in February, during the Summer. Floral bud differentiation starts after leaves that will emerge the following year have developed. This occurs during a period of maximum decrease in edaphic humidity and an increase in air temperature (November). The inflorescence is the only branching that develops while the apical bud continues developing leaves. In June, the small inflorescence reaches the neck of the bulb and surpasses it followed by those leaves developed before the inflorescence that surround both the inflorescence and the apical foliar bud. The foliar bud will continue its development, and in July two of the leaves expand, while the smaller ones remain inside the bulb until the following year’s Lomas season. It can be noted that the reproductive success of Ismene amancaes in its initial development depends on the photoreserves accumulated in the bulb the previous growth period.

Descripción del cromosoma profásico en la meiosis I de Bostryx conspersus / Description of the profasic chromosome in Meiosis I of Bostryx conspersus

Bostryx es uno de los géneros de mayor diversidad dentro de los Orthalicidae (Gastropoda), siendo B. conspersus una especie endémica del ecosistema de Lomas, del desierto Costero peruano. En el presente trabajo los cromosomas de la profase I de meiosis de los espermatocitos de Bostryx conspersus son descritos.

Bostryx is among the most diverse genera within the Orthalicidae (Gastropoda). Bostryx conspersus is endemic of the Lomas ecosystem in Peruvian Coastal Desert. In this paper, chromosomes in prophase I of meiosis of spermatocytes Bostryx conspersus are described.

Hallazgo de dos nidos activos de Phytotoma raimondii, Tackzanowski, 1883, cortarrama peruana / Discovery of two active nests of Phytotoma raimondii, Tackzanowski, 1883, Peruvian Plantcutter

Dos nidos de Phytotoma raimondii, cortarrama peruana, fueron hallados en la localidad de El Gramadal, distrito de Huarmey, Provincia de Huarmey, Departamento de Áncash. Ambos nidos estaban en arbustos de Grabowskia boerhaaviaefolia palo negro. Uno de ellos contenía dos huevos y el segundo dos pichones de unos diez días a dos semanas de edad. Una semana después, el 14 de abril de 2010 se ubicó muy cerca del segundo nido que ya estaba vacío, a dos volantones que seguían a sus padres. Son los primeros nidos activos reportados que se han encontrado desde 1934.

Two nests belonging to Phytotoma raimondii, the Peruvian plantcutter, were found in El Gramadal, at Huarmey, Áncash. Both nests were in shrubs of Grabowskia boerhaaviaefolia, commonly known as palo negro. One nest had two eggs and the other nest had two chicks that were approximately two weeks old. Two weeks later, two fledglings were found following presumed parents. These chicks were close to the second nest, which was empty. These are the first nests reported for Phytotoma raimondii since 1934.

Demographic study of two population outbreaks of Elasmoderus wagenknechti (Liebermann) (Orthoptera: Tristiridae) in the transitional desert of Chile

Under certain environmental conditions, several species of grasshoppers inhabiting rangeland areas (e.g., inter-valleys) of the Chilean transitional desert can irrupt demographically. One of them is Elasmoderus wagenknechti (Liebermann), an endemic species. We studied two outbreaks occurred in 1996 and 1999. The objectives of the research were to (i) estimate some demographic parameters associated with the aforementioned events, and (ii) compare between them the population parameters. The parameters we studied were density (ind/m²), sexual proportion, female fertility (i.e., eggs/female), and the relationship eggs/female versus female size. Density (ind/m²) ranged from 0.2 to 0.4 in 1996 and from 0.5 to 0.6 in 1999. ANOVA-tests registered differences in density among study sites and between years. In some of the study sites, females were more abundant than males (e.g., Lomas del Sauce). Females fertility ranged from 27 to 39 eggs per female, with significant differences among sites in 1996 but not in 1999. For females of 30-50 mm body size, a linear relationship was detected between egg number/female and body size. It is concluded that the E. wagenknechti outbreaks are site-specific in the study area and that the demographic parameters examined show a high variability among sites and between events.

Sob certas condições ambientais, diversas espécies de gafanhotos que habitam áreas de campos, como as áreas entre vales do deserto transicional do Chile, podem experimentar surtos populacionais. Uma dessas espécies é Elasmoderus wagenknechti (Liebermann), espécie endêmica. Nós estudamos dois surtos que ocorreram em 1996 e 1999. Os objetivos da pesquisa foram (1) estimar alguns parâmetros demográficos associados aos eventos acima indicados, e (2) comparar os parâmetros entre os eventos. Os parâmetros estudados foram densidade (indivíduos/m²), razão sexual, fertilidade da fêmea (i.e., ovos/fêmea), e a relação entre a fertilidade e o tamanho corporal da fêmea. O intervalo da densidade do evento foi estimado entre 0,2 e 0,4 indivíduos/m² em 1996, e entre 0,5 e 0,6 indivíduos /m² em 1999. Foram encontradas diferenças (análise de variância) na densidade entre os locais para o mesmo evento, e entre os eventos. As fêmeas foram mais numerosas que os machos em alguns locais estudados (e.g., Lomas del Sauce). Foi estimado um intervalo médio de 27-39 ovos/fêmea, existindo diferenças entre os locais no evento de 1996, mas não no evento de 1999. Para fêmeas de longitude corporal de 30-35 mm. foi detectada uma relação linear entre número de ovos/fêmea e tamanho corporal. Em conclusão, a magnitude do evento na área de estudo é específica do local; além do que para os parâmetros demográficos examinados existe uma acentuada variabilidade entre locais e entre os eventos.

Saharan dust - a carrier of persistent organic pollutants, metals and microbes to the Caribbean? / Polvo sahariano: ¿portador de contaminantes orgánicos persistentes, metales y microbios al Caribe?

An international team of scientists from government agencies and universities in the United States, U.S. Virgin Islands (USVI), Trinidad & Tobago, the Republic of Cape Verde, and the Republic of Mali (West Africa) is working together to elucidate the role Saharan dust may play in the degradation of Caribbean ecosystems. The first step has been to identify and quantify the persistent organic pollutants (POPs), trace metals, and viable microorganisms in the atmosphere in dust source areas of West Africa, and in dust episodes at downwind sites in the eastern Atlantic (Cape Verde) and the Caribbean (USVI and Trinidad & Tobago). Preliminary findings show that air samples from Mali contain a greater number of pesticides, polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) and in higher concentrations than the Caribbean sites. Overall, POP concentrations were similar in USVI and Trinidad samples. Trace metal concentrations were found to be similar to crustal composition with slight enrichment of lead in Mali. To date, hundreds of cultureable micro-organisms have been identified from Mali, Cape Verde, USVI, and Trinidad air samples. The sea fan pathogen, Aspergillus sydowii, has been identified in soil from Mali and in air samples from dust events in the Caribbean. We have shown that air samples from a dust-source region contain orders of magnitude more cultureable micro-organisms per volume than air samples from dust events in the Caribbean, which in turn contain 3-to 4-fold more cultureable microbes than during non-dust conditions. Rev. Biol. Trop. 54 (Suppl. 3): 9-21. Epub 2007 Jan. 15.

Un grupo internacional de agencias gubernamentales y universidades de los Estados Unidos, las Islas Vírgenes (EUA), Trinidad y Tobago, la República de Cabo Verde y la República de Mali (África Oeste), está trabajando en conjunto para elucidar el papel que el polvo del Sahara puede estar jugando en el deterioro de los ecosistemas caribeños. El primer paso ha sido identificar y cuantificar los Contaminantes Orgánicos Persistentes (POPs, por sus siglas en inglés), los metales traza y los microorganismos viables presentes en la atmósfera de las áreas fuente de polvo de África occidental y en áreas ubicadas en la dirección del viento, como el Atlántico este (Cabo Verde) y el Caribe (IVEUA y Trinidad y Tobago), durante los episodios de transporte de polvo. Resultados preliminares indican que las muestras de aire de Mali contienen mayor número y mayores concentraciones de pesticidas, bifenilos policlorinados (PCBs) e hidrocarburos policíclicos aromáticos (PAHs) que las de los sitios del Caribe. Las concentraciones de POPs fueron similares en las muestras de USVI y de Trinidad. Se encontró que las concentraciones de metales traza fueron similares a las de la composición de la corteza, con un ligero enriquecimiento de plomo en Mali. Hasta la fecha, cientos de microorganismos cultivables han sido identificados en las muestras de Mali, Cabo Verde, IVEUA y Trinidad. Hallamos el patógeno de los abanicos de mar, Aspergillus sydowi, en las muestras de aire de Mali y en las muestras del Caribe durante polvaredas. Hemos demostrado que las muestras de aire provenientes de una región fuente de polvo, contienen más microorganismos cultivables por volumen -en órdenes de magnitud- que las muestras de aire tomadas en polvaredas en el Caribe, las cuales a su vez contienen tres a cuatro veces más microorganismos cultivables que aquellas tomadas cuando no hay polvaredas.

Distribución altitudinal de hongos queratinofilos, epifitos y endófitos en suelos desérticos del norte chileno (II Región, 23°L. S y 68°L. W) / Altitudinal distribution of keratinophilic, epiphytic and endophytic fungi from desertic soils in northern Chile (II Region, 23°L. S y 68°L. W)

En una zona desértica del norte chileno entre los 2200 y 4500m de altura y en 2 períodos estacionales, se determinó la presencia y composición de las comunidades de microhongos queratinofílicos, epifítos y endófitos mediante el empleo de un anzuelo queratínico y vegetal. Las metodologías empleadas permitieron apreciar ciertos aspectos ecológicos de un grupo de hongos tolerantes al estrés y la persistencia en el tiempo de algunas de sus poblaciones en 3 gradientes altitudinales. En 79 muestras de suelo y 67 de vegetales se obtuvieron 1111 aislamientos, repartidos en 78 géneros y 172 especies y los integrantes de los 18 géneros más frecuentes en ambos sustratos y en todas las altitudes reunieron el 80 porciento del total de presencia fúngica. Los Zygomycetes fueron representados por 4 géneros, los Ascomycetes por 11, los Coelomycetes por 8 y los Hyphomycetes por 70. En este último grupo los principales taxa en orden decreciente fueron: Ulocladium, Penicillium, Aspergillus, Acremonium, Alternaria, Cladosporium, Fusarium, Paecilomyces, Trichoderma, Bipolaris, Rhizopus, Aphanocladium y Verticillium. Los integrantes del género Ulocladium Aspergillus, Penicillium y Alternaria obtuvieron las mayores frecuencias en el primer escalón altitudinal en las 3 metodologías, mientras en el escalón más alto fue Penicillium, Ulocladium, Cladosporium y Acremonium. Ocho especies mantuvieron una alta presencia en la mayoría de los sustratos y altitudes. Ulocladium atrum, U. chartarum, Alternaria alternata, Emericella nidulans, Cladosporium cladosporioides, U. botrytis, Aspergillus fumigatus y A. niger, junto a una proporción mayoritaria de especies esporádicas o de baja frecuencia ("ruderal"). La mayoría de los Onygenales y anamorfos relacionados, se aislaron principalmente en verano entre los 2200 y los 4000m. Los más frecuentes fueron: Auxarthron umbrinum, Chrysosporium tropicum, Malbranchea gypsea y Geomyces pannorum. La presencia más alta del grupo (17,4 porciento) en todos los escalones y la persistencia a través del tiempo correspondió a G. pannorum...

Las Necesidades Humanas Básicas en un campamento de refugiados. A propósito de una experiencia docente en el Sahara / Basic human necessities ina refugee camp. Apropos of to an educational experience in the Sahara

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Dust and sand storms : Characteristics , vulnerability, awareness and preparedness

This paper provides a review and analysis of dust storm phenomena in may parts of the world. The study investigates their types, general characteristics, hazards, preparedness and their relation to atmospheric elements. A suggested mechanism of dust storm formation is discussed as well as detailed study of dust storms of desert depression type, including some case studies. The results show the importance of descending motion for true dust storms and that the transverse indirect circulation may play an important role in these phenomena. The relationship between dust storms over China and the suppression of the Walker cell, as a result of El Niño events, is also discussed. (AU)