Spatial analysis of canine leishmaniasis in an area of transmission of the semi-arid region of the State of Paraíba, Brazil / Análise espacial da leishmaniose canina em uma área de transmissão do semiárido paraíbano, Brasil

Abstract Visceral leishmaniasis is a widely distributed zoonosis and canine infection is an important indicator of risk for the occurrence of the disease in humans. The goal of this analysis was to study the spatial clustering of canine leishmaniasis (CL) in the municipality of Santa Luzia, state of Paraíba. For this, 749 samples of canine plasma were tested using three serological tests. The dog was considered positive if it reacted in two serological tests. The location of the residences was performed with a Global Positioning System receiver (GPS Garmin® eTrex 30), and used to perform georeferencing and spatial analysis. The prevalence of CL was 15.49% and it was observed that most cases of the urban area were concentrated in the Frei Damião neighborhood, on the outskirts of the city, where a high-risk cluster for the occurrence of the disease was formed (p = 0.02; RR = 2.48). No statistically significant cluster was observed in rural areas. CL is widely distributed in the municipality of Santa Luzia in a heterogeneous manner and with a tendency to urbanization. The areas identified with high prevalence and highest risk should be prioritized to maximize the efficiency of the Visceral Leishmaniasis Surveillance and Control Program and minimize the chance of new canine and human cases.

Resumo A leishmaniose visceral é uma zoonose amplamente distribuída, e a infecção canina é um importante indicador de risco para a ocorrência da doença em humanos. O objetivo foi estudar o comportamento espacial da leishmaniose canina (LC) no município de Santa Luzia, estado da Paraíba. Para tal, 749 amostras de plasma canino foram testadas por meio de três técnicas sorológicas. O cão seria considerado positivo se apresentasse duas sorologias reagentes. A localização das residências foi realizado pelo receptor de Sistema de Posicionamento Global (GPS Garmin® eTrex 30) e usado para a realização do georreferenciamento e análise espacial. A prevalência da LC foi de 15,49% e observou-se que a maioria dos casos de LC da zona urbana estava concentrada no bairro Frei Damião, localizado na periferia da cidade, onde se formou um cluster de alto risco para ocorrência da doença (p = 0,02; RR = 2,48). Nenhum cluster estatisticamente significativo foi observado na zona rural. A LC está amplamente distribuída no município de Santa Luzia, porém de forma heterogênea e com tendência à urbanização. As áreas identificadas com intensa prevalência e maior risco devem ser priorizadas para maximizar a eficiência do Programa de Vigilância e Controle da Leishmaniose Visceral e minimizar a chance de novos casos caninos e humanos.

Prevalence of Systemic Arterial Hypertension and Associated Factors Among Adults from the Semi-Arid Region of Pernambuco, Brazil / Prevalência e Fatores Associados à Hipertensão Arterial Sistêmica em Adultos do Sertão de Pernambuco, Brasil

Abstract Background: Systemic arterial hypertension is a substantial public health problem responsible for millions of deaths per year worldwide. However, little is known about the epidemiology of this disease in areas distant from large urban centers in Brazil. Such information is necessary to plan health promotion strategies. Objective: To estimate the prevalence of hypertension and determine its associated factors in adults residing in the semi-arid region of the state of Pernambuco, Northeastern Brazil. Method: This is a cross-sectional study conducted with a random sample of male and female adults. Individuals with systolic blood pressure ≥ 140 mm/Hg and/or diastolic blood pressure ≥ 90 mm/Hg and those who reported being under treatment with antihypertensive drugs were considered hypertensive. We collected data on demographic, socioeconomic, behavioral, and anthropometric characteristics, as well as health and nutrition. The statistical analysis used Pearson's chi-square test, the chi-square test for trend, and multivariate Poisson regression analysis. A p-value < 0.05 in the final model was considered indicative of statistical significance. Results: The sample consisted of 416 individuals, and the prevalence of hypertension was 27.4% (95%CI 23.2 - 32.0). In the final model, the independent predictors of hypertension were age of 40 years or older (p = 0.000), low economic class (p = 0.007), smoking (p = 0.023), overweight determined by the body mass index (p = 0.003), and reduced glucose tolerance/diabetes mellitus (p = 0.012). Conclusion: The prevalence of hypertension was high and related to important risk factors. Thus, prevention and control strategies are recommended.

Resumo Fundamento: A hipertensão arterial sistêmica (HAS) constitui grande problema de saúde pública, responsável por milhões de mortes por ano no mundo. Apesar disso e frente à necessidade de informações para o delineamento de estratégias de promoção da saúde, pouco se conhece sobre a epidemiologia da doença em regiões distantes dos grandes centros urbanos brasileiros. Objetivo: Estimar a prevalência e verificar os aspectos associados à HAS em adultos do sertão de Pernambuco, Brasil. Métodos: Estudo de delineamento transversal, com uma amostra aleatória de adultos de ambos os sexos. Foram considerados hipertensos aqueles que apresentaram pressão arterial sistólica ≥ 140 mmHg e/ou diastólica ≥ 90 mmHg, além daqueles que relataram estar em tratamento com anti-hipertensivos. Informações demográficas, socioeconômicas, comportamentais, antropométricas e de saúde e nutrição foram coletadas. Foram aplicados os testes do 2 de Pearson, c2 para tendência e a regressão multivariada de Poisson. No modelo final, foi considerada significância estatística quando p < 0,05. Resultados: A amostra foi composta por 416 indivíduos e a prevalência de HAS foi de 27,4% (IC95% 23,2 - 32,0). No modelo final, foram identificados como preditores independentes da HAS a faixa etária a partir dos 40 anos (p = 0,000), classe econômica baixa (p = 0,007), tabagismo (p = 0,023), excesso de peso pelo índice de massa corporal (p = 0,003) e adultos com tolerância à glicose diminuída/diabetes mellitus (p = 0,012). Conclusão: A prevalência de HAS é elevada e se relaciona com fatores de risco importantes, logo, são recomendáveis ações de prevenção e controle.

Physiological response of Cucurbita pepo var. pepo mycorrhized by Sonoran desert native arbuscular fungi to drought and salinity stresses

ABSTRACT Plants response to symbiosis with arbuscular mycorrhizal fungi (AMF) under water stress is important to agriculture. Under abiotic stress conditions native fungi are more effective than exotics in improving plant growth and water status. Mycorrhization efficiency is related to soil fungi development and energy cost-benefit ratio. In this study, we assessed the effect on growth, water status and energy metabolism of Cucurbita pepo var. pepo when inoculated with native AMF from the Sonoran desert Mexico (mixed isolate and field consortium), and compared with an exotic species from a temperate region, under drought, low and high salinity conditions. Dry weights, leaf water content, water and osmotic potentials, construction costs, photochemistry and mycorrhization features were quantified. Under drought and low salinity conditions, the mixed isolate increased plant growth and leaf water content. Leaf water potential was increased only by the field consortium under drought conditions (0.5-0.9 MPa). Under high salinity, the field consortium increased aerial dry weight (more than 1 g) and osmotic potential (0.54 MPa), as compared to non-mycorrhized controls. Plants inoculated with native AMF, which supposedly diminish the effects of stress, exhibited low construction costs, increased photochemical capacity, and grew larger external mycelia in comparison to the exotic inoculum.

Photosynthetic capacity and water use efficiency in Ricinus communis (L) under drought stress in semi-humid and semi-arid areas

ABSTRACT Castor bean is one of the crops with potential to provide raw material for production of oils for biodiesel. This species possess adaptive mechanisms for maintaining the water status when subjected to drought stress. A better understanding these mechanisms under field conditions can unravel the survival strategies used by this species. This study aimed to compare the physiological adaptations of Ricinus communis (L.) in two regions with different climates, the semi-arid and semi-humid subject to water stress. The plants showed greater vapor pressure deficit during the driest hours of the day, which contributed to higher values of the leaf temperature and leaf transpiration, however, the VPD(leaf-air) had the greatest effect on plants in the semi-arid region. In both regions, between 12:00 p.m. and 2:00 p.m., the plants presented reduction in the rates of photosynthesis and intracellular CO2 concentration in response to stomatal closure. During the dry season in the semi-arid region, photoinhibition occurred in the leaves of castor bean between 12:00 p.m. and 2:00 p.m. These results suggest that castor bean plants possess compensatory mechanisms for drought tolerance, such as: higher stomatal control and maintenance of photosynthetic capacity, allowing the plant to survive well in soil with low water availability.

Seed dormancy of Ochradenus baccatus (Resedaceae), a shrubby species from Arabian desert regions / Dormición de semillas de Ochradenus baccatus (Resedaceae), una especie arbustiva de las regiones desérticas arábicas

Abstract:Ochradenus baccatus is a perennial glycophyte growing in Middle East and it is one of the most important food sources for many animal species in desert regions. The aim of our study was to investigate the effects of seed storage, light, temperature and gibberellic acid (GA3) on germination of O. baccatus seeds. We also investigated the germination characteristics of O. baccatus seeds under different saline concentration and their capability to recover germination once they were transferred to distilled water. Seeds were stored at room temperature (20 ± 2 ºC) and at -18 ºC. Germination tests were conducted at alternating temperatures of 15/25, 20/30 and 25/35 ºC in either continuous darkness or photoperiod of 12-h dark/12-h light. To study the effect of GA3 on germination of O. baccatus seeds, freshly-collected seeds and stored seeds were soaked for 24 h in a GA3 water solution (1 g/L) before sowing. To assess the salinity tolerance during germination, seeds were germinated under different salinity levels (100, 200 and 400 mM NaCl). Stored seeds at room temperature and -18 ºC germinate equally well at different temperature regimes and light conditions. However, freshly matured seeds were not able to germinate even when they were treated with GA3. On the contrary, stored seeds at room temperature and -18 ºC treated with GA3 increase the final germination percentages. These results indicated that O. baccatus seeds have physiological dormancy and they need to be stored in order to break their dormancy. In the present study, one year of storage did not show a significant variation in germination between the two storage conditions assayed. Therefore, further research is needed to know about the maximum storage period for O. baccatus seeds under different storage conditions. Very few O. baccatus seeds (less than 5 %) germinated at the tested lowest concentration of NaCl. However, ungerminated seeds were able to germinate when salinity stress was alleviated. In conclusion, O. baccatus seeds have physiological dormancy, and seed storage (at room temperature and at -18 ºC) for one year is effective for breaking this dormancy. In addition, O. baccatus seeds present ability to remain viable in saline conditions and they will be able to germinate once the salinity level decrease. Rev. Biol. Trop. 64 (3): 965-974. Epub 2016 September 01.

ResumenOchradenus baccatus es un glicófito perenne que crece en oriente Medio y es una de las fuentes de alimentación más importantes para muchas especies animales de regiones desérticas. El objetivo de nuestro estudio fue investigar los efectos del almacenamiento de semillas, luz, temperatura y ácido giberélico (GA3) en la germinación de semillas de O. baccatus. También se ha investigado la germinación de semillas de O. baccatus bajo diferentes concentraciones salinas y su capacidad para recuperar la germinación una vez que fueron transferidas a agua destilada. Las semillas se conservaron a temperatura ambiente (20 ± 2 ºC) y a -18 ºC. Los ensayos de germinación se realizaron a temperaturas alternas de 15/25, 20/30 y 25/35 ºC bajo oscuridad continua o fotoperiodo de 12-h oscuridad/12-h luz. Para estudiar el efecto del GA3 en la germinación de semillas de O. baccatus, semillas recién recolectadas y semillas almacenadas se sumergieron durante 24 h en una solución acuosa de GA3 (1 g/L) antes de la siembra. Para evaluar la tolerancia a la salinidad durante la germinación, la semillas fueron germinadas bajo diferentes niveles de salinidad (100, 200 y 400 mM ClNa). Las semillas conservadas a temperatura ambiente y a -18 ºC germinaron igualmente bien en los diferentes regímenes de temperatura y condiciones de iluminación. Sin embargo, las semillas recién maduradas fueron incapaces de germinar incluso cuando se trataron con GA3. Por el contrario, las semillas almacenadas tratadas con GA3 incrementaron los porcentajes finales de germinación. Estos resultados indican que las semillas de O. baccatus tienen dormición fisiológica y necesitan ser almacenadas para romperla. En este estudio, un año de conservación no supuso una variación significativa en la germinación entre las dos condiciones de conservación ensayadas. Por lo tanto, se precisan investigaciones adicionales para conocer cuáles son los periodos máximos de almacenamiento de semillas de O. baccatus bajo diferentes condiciones de conservación. Muy pocas semillas de O. baccatus (menos del 5 %) germinaron a la concentración más baja de ClNa. Sin embargo, las semillas no germinadas fueron capaces de germinar cuando el estrés salino fue aliviado. En conclusión, las semillas de O. baccatus tienen dormición fisiológica y el almacenamiento de las mismas (a temperatura ambiente y a -18 ºC) durante un año es eficaz para romper dicha dormición. Además, las semillas de O. baccatus presentan capacidad para permanecer viables en condiciones salinas y serán capaces de germinar una vez que el nivel de salinidad disminuya.

Establishment of Mimosa biuncifera (Fabaceae) inoculated with arbuscular mycorrhizal fungi in greenhouse and field drought conditions / Establecimiento de Mimosa biuncifera (Fabaceae) inoculada con hongos micorrízicos arbusculares en invernadero y campo, en condiciones de sequía

AbstractMexico is dominated by arid or semi-arid ecosystems, predominantly characterized as xeric shrublands. These areas are frequently deteriorated due to agriculture or over-grazing by livestock (sheep and goats). The vegetation type mainly consists of thorny plant species, and among these, the dominant one in overgrazed areas is catclaw (Mimosa biuncifera). This is a nurse plant that facilitates establishment of other vegetation and promotes plant succession. Catclaw plants form a mutualistic association with arbuscular mycorrhizal fungi (AMF), which improves uptake of nutrients and water. The objective of this study was to determine the effect of inoculating catclaw plants with native AMF and starting their growth under a low water availability treatment in a greenhouse, and later transplanting them to field conditions of drought and deterioration. Field plants were evaluated according to their survivorship and growth. The seeds of catclaw plants and soil with AMF spores were collected in the Mezquital Valley of Hidalgo State, in Central Mexico. Seedlings were grown in individual pots in a greenhouse. The experimental design consisted of two levels of pot irrigation, wet (W) and dry (D), as well as the presence (M+) or absence (M-) of AMF inoculum, with 20 replicates for each treatment. The following plant parameters were recorded every week: height, number of leaves and pinnae, and mean diameter of coverage. After 20 weeks in the greenhouse, determination was made of fresh and dry biomass, relative growth rate (RGR), root/shoot ratio, real evapotranspiration (RET), water-use efficiency (WUE), and percentage of mycorrhizal colonization. The remaining plants growing under the dry treatment (M+ and M-) were then transplanted to a semi-arid locality in the Mezquital Valley. During one year, monthly records were kept of their height, number of leaves, mean diameter of coverage and survival. Results showed that compared to greenhouse plants under other treatments, those under the wet mycorrhizal (WM+) treatment were taller, had more pinnae, and were characterized by greater coverage, faster RGR, and greater fresh and dry biomass. Moreover, inoculated plants (WM+ and DM+) showed higher WUE than those uninoculated (WM- and DM-, respectively). After one year in field conditions, there was a higher survival rate for previously inoculated versus uninoculated plants. Hence, mycorrhization of M. biuncifera with native AMF inoculum increased plant efficiency in biomass production, thus favoring establishment and survival in field conditions. We concluded that inoculation of catclaw plants is recommendable for revegetation programs in deteriorated semi-arid zones. Rev. Biol. Trop. 64 (2): 791-803. Epub 2016 June 01.

ResumenMás de la mitad del territorio mexicano está dominado por ecosistemas áridos y semiáridos. El principal tipo de vegetación de estos ambientes son matorrales xerófilos y normalmente están deteriorados por agricultura y sobrepastoreo de ovejas y cabras inducido por la actividad humana. Las plantas espinosas dominan en estas zonas, como el gatuño (Mimosa biuncifera Benth., Fabaceae), que es una planta nodriza que promueve la sucesión vegetal. Las plantas de gatuño forman junto con hongos micorrizógenos arbusculares (HMA), una asociación mutualista llamada micorriza arbuscular que mejora la captación vegetal de nutrimentos y agua. El objetivo de este trabajo fue determinar el efecto de la inoculación con HMA nativos en plantas de gatuño, para evaluar su crecimiento y establecimiento bajo un tratamiento de baja disponibilidad hídrica, tanto en condiciones de invernadero como de campo. Para esto, se recolectaron semillas de Mimosa biuncifera y suelo con esporas de HMA en el Valle del Mezquital, estado de Hidalgo, en el Centro de México. Las plántulas fueron cultivadas en macetas individuales en condiciones de invernadero bajo un diseño experimental que consistió en dos tratamientos de riego de las macetas, húmedo (W) y seco (D), y dos tratamientos de inoculación: con y sin inóculo de HMA (M+, M-). Cada tratamiento tuvo 20 repeticiones. Semanalmente se registró altura, diámetro medio de la cobertura y número de hojas y pinnas de las plantas. Después de 20 semanas, se determinaron biomasa húmeda y seca, tasa relativa de crecimiento (TRC), proporción raíz vástago, evapotranspiración real, eficiencia en el uso del agua (WUE) y porcentaje de colonización micorrícica. Posteriormente, los individuos del tratamiento seco (M+ y M-) fueron trasplantados a una localidad semiárida en el Valle del Mezquital, donde la altura, número de hojas y supervivencia fueron registrados mensualmente durante un año. Los resultados muestran que las plantas en el tratamiento húmedo y micorrizado (WM+) tuvieron una mayor altura, cobertura vegetal, biomasa húmeda y seca, TRC y más pinnas que las plantas de los otros tratamientos; también los tratamientos micorrizados (WM+ y DM+) tuvieron mayor WUE que la plantas sin inóculo (M-). En condiciones de campo, después de un año, la supervivencia de las plantas M+ fue mayor que en los testigos. Se concluyó que la micorrización de M. biuncifera con inóculo nativo incrementa su eficiencia en la producción de biomasa y favorece el establecimiento y supervivencia en condiciones de campo. Finalmente, se recomienda la inoculación de plantas de gatuño con HMA en programas de revegetación de zonas semiáridas deterioradas.

Seed colour affects light and temperature requirements during germination in two Lotus species (Fabaceae) of the Arabian subtropical deserts / El color de la semilla afecta los requerimientos de luz y temperatura durante la germinación en dos especies de Lotus (Fabaceae) de los desiertos subtropicales árabes

AbstractHeterogeneity in seeds mostly occurs due to physiological, environmental and genetic factors, and these could affect seed dormancy and germination. Therefore, the aim of our study was to assess the effect of seed colour on germination behavior. For this, both light and temperature requirements were assessed in Lotus glinoides and Lotus halophilus (Fabaceae) from the hyper-arid deserts of the United Arab Emirates. Germination was assessed in terms of both final germination level (percentage) and germination rate, as expressed by Timson’s germination velocity index. Lotus glinoides produces black and yellow-colored seeds, and L. halophilus produces green and yellow seeds. Different seed lots were germinated in both light and darkness at different temperatures. Yellow seeds of the two species attained significantly lower germination, compared to black and green seeds. There was no specific light or temperature requirements for the germination of the two coloured seeds of L. glinoides; the effect of interactions between seed colour and both light and incubation temperature, were not significant on the final germination percentage. in L. halophilus, green seeds germinated significantly more in both light and darkness at lower temperatures (15/25 °C) and in light at higher temperatures (25/35 °C), compared to yellow seeds. Yellow seeds germinated faster, compared to black at 15/25 °C in L. glinoides and compared to green seeds at 15/25 °C and 25/35 °C in L. halophilus. Seed colour variation, at least in L. halophilus, could be a survival strategy that would determine the time of germination throughout the year in the unpredictable desert environment. Rev. Biol. Trop. 64 (2): 483-492. Epub 2016 June 01.

ResumenLa heterogeneidad en las semillas se produce principalmente debido a factores fisiológicos, genéticos y ambientales, y esto podría afectar latencia de las semillas y la germinación. Por lo tanto, el objetivo de nuestro estudio fue evaluar el efecto del color de la semilla en el comportamiento de la germinación. Para ello, tanto los requisitos de luz y temperatura fueron evaluados en Lotus glinoides y Lotus halophilus (Fabaceae) desde los desiertos hiper-árida de los Emiratos Árabes Unidos. La germinación se evaluó en términos de nivel final de germinación (porcentaje) y la tasa de germinación, expresado por el índice de velocidad de germinación de Timson. L. glinoides produce semillas negro y de color amarillo, y L. halophilus produce semillas verdes y amarillas. Los diferentes lotes de semillas fueron germinadas en luz y oscuridad a diferentes temperaturas. Semillas amarillas de las dos especies alcanzaron significativamente menor germinación, en comparación con las semillas negras y verdes. No había requisitos específicos de luz o temperatura para la germinación de las semillas de dos colores de L. glinoides; el efecto de las interacciones entre color de la semilla y la luz y la temperatura de incubación, no fueron significativas en el porcentaje final de germinación. En L. halophilus, semillas verdes germinados significativamente más en la luz y la oscuridad a temperaturas más bajas (15/25 °C) ya la luz a temperaturas más altas (25/35 °C), en comparación con semillas amarillas. Semillas amarillas germinaron más rápido, en comparación con el negro a 15/25 °C en L. glinoides y en comparación con semillas verdes a 15/25 °C y 25/35 °C en L. halophilus. La variación del color de la semilla, al menos en L. halophilus, podría ser una estrategia de supervivencia que determinaría el momento de la germinación durante todo el año en el entorno del desierto impredecible.

Antifungal activity of extracts from Atacama Desert fungi againstParacoccidioides brasiliensis and identification ofAspergillus felis as a promising source of natural bioactive compounds

Fungi of the genus Paracoccidioides are responsible for paracoccidioidomycosis. The occurrence of drug toxicity and relapse in this disease justify the development of new antifungal agents. Compounds extracted from fungal extract have showing antifungal activity. Extracts of 78 fungi isolated from rocks of the Atacama Desert were tested in a microdilution assay against Paracoccidioides brasiliensis Pb18. Approximately 18% (5) of the extracts showed minimum inhibitory concentration (MIC) values≤ 125.0 µg/mL. Among these, extract from the fungus UFMGCB 8030 demonstrated the best results, with an MIC of 15.6 µg/mL. This isolate was identified as Aspergillus felis (by macro and micromorphologies, and internal transcribed spacer, β-tubulin, and ribosomal polymerase II gene analyses) and was grown in five different culture media and extracted with various solvents to optimise its antifungal activity. Potato dextrose agar culture and dichloromethane extraction resulted in an MIC of 1.9 µg/mL against P. brasiliensis and did not show cytotoxicity at the concentrations tested in normal mammalian cell (Vero). This extract was subjected to bioassay-guided fractionation using analytical C18RP-high-performance liquid chromatography (HPLC) and an antifungal assay using P. brasiliensis. Analysis of the active fractions by HPLC-high resolution mass spectrometry allowed us to identify the antifungal agents present in the A. felis extracts cytochalasins. These results reveal the potential of A. felis as a producer of bioactive compounds with antifungal activity.

The influence of microhabitat on the population dynamics of four herbaceous species in a semiarid area of northeastern Brazil / A influência dos microhabitats sobre a dinâmica de populações de quatro espécies herbáceas em uma área semiárida no nordeste do Brasil

Abstract Variation in annual rainfall is considered the most important factor influencing population dynamics in dry environments. However, different factors may control population dynamics in different microhabitats. This study recognizes that microhabitat variation may attenuate the influence of climatic seasonality on the population dynamics of herbaceous species in dry forest (Caatinga) areas of Brazil. We evaluated the influence of three microhabitats (flat, rocky and riparian) on the population dynamics of four herbaceous species (Delilia biflora, Commelina obliqua, Phaseolus peduncularis and Euphorbia heterophylla) in a Caatinga (dry forest) fragment at the Experimental Station of the Agronomic Research Institute of Pernambuco in Brazil, over a period of three years. D. biflora, C. obliqua and P. peduncularis were found in all microhabitats, but they were present at low densities in the riparian microhabitat. There was no record of E. heterophylla in the riparian microhabitat. Population size, mortality rates and natality rates varied over time in each microhabitat. This study indicates that different establishment conditions influenced the population size and occurrence of the four species, and it confirms that microhabitat can attenuate the effect of drought stress on mortality during the dry season, but the strength of this attenuator role may vary with time and species.

Resumo A variação anual na precipitação é considerada o fator mais importante que influencia a dinâmica populacional em ambientes secos. No entanto, diferentes fatores podem controlar a dinâmica populacional em diferentes microhabitats. A hipótese deste estudo é que as variações de microhabitats podem atenuar a influência da sazonalidade climática sobre a dinâmica populacional de espécies herbáceas em uma áreas floresta seca (Caatinga) no Brasil. Então, objetivou-se avaliar a influência de três microhabitats (plano, rochoso e ciliar) sobre a dinâmica das populações de quatro espécies herbáceas (Delilia biflora, Commelina obliqua, Phaseolus peduncularis e Euphorbia heterophylla) em um fragmento de Caatinga da Estação Experimental do Instituto de Pesquisas Agronômicas de Pernambuco, no Brasil, durante um período de três anos. D. biflora, C. obliqua e P. peduncularis foram encontrados em todos os microhabitats, mas elas estavam presentes em baixas densidades no microhabitat ciliar. Não houve registro de E. heterophylla no microhabitat ciliar. O tamanho das populações, as taxas de mortalidade e de natalidade variaram ao longo do tempo em cada microhabitat. Este estudo indica que diferentes as condições de estabelecimento influenciaram o tamanho das populações e a ocorrência das quatro espécies e confirma que microhabitat pode atenuar o efeito do estresse hídrico sobre a mortalidade durante a estação seca, mas a força desse papel atenuador pode variar com o tempo e a espécie considerada.

Interruptions of nurses' activities and patient safety: an integrative literature review / Interrupções de atividades de enfermeiros e a segurança do paciente: revisão integrativa da literatura / Interrupciones de actividades de enfermeros y la seguridad del paciente: revisión integradora de la literatura

OBJECTIVES: to identify characteristics related to the interruption of nurses in professional practice, as well as to assess the implications of interruptions for patient safety. METHOD: integrative literature review. The following databases were searched: Pubmed/Medline, LILACS, SciELO and Cochrane Library, using the descriptors interruptions and patient safety. An initial date was not established, but the final date was December 31, 2013. A total of 29 papers met the inclusion criteria. RESULTS: all the papers included describe interruptions as a harmful factor for patient safety. Data analysis revealed three relevant categories: characteristics of interruptions, implications for patient safety, and interventions to minimize interruptions. CONCLUSION: interruptions favor the occurrence of errors in the health field. Therefore, there is a need for further studies to understand such a phenomenon and its effects on clinical practice. .

OBJETIVOS: identificar características relacionadas à interrupção de enfermeiros em sua prática profissional, bem como avaliar as implicações para a segurança do paciente. MÉTODO: foi realizada revisão de literatura do tipo integrativa, com busca nas bases de dados Pubmed/Medline, LILACS, SciELO e Biblioteca Cochrane, utilizando os descritores interruptions e patient safety. A data inicial não foi limitada e a data final foi 31 de dezembro de 2013, identificando-se 29 artigos que atenderam aos critérios de inclusão. RESULTADOS: todos os artigos revisados descreveram a interrupção como fator prejudicial à segurança do paciente. A análise destes estudos revelou três categorias relevantes: características da interrupção, implicações da interrupção para a segurança do paciente e intervenções para minimizar as interrupções. CONCLUSÃO: a interrupção favorece a ocorrência de erros na saúde. Assim, notou-se necessidade de novas pesquisas para compreender tal fenômeno e seus efeitos na prática clínica. .

OBJETIVOS: identificar características relacionadas a la interrupción que sufren los enfermeros en su práctica profesional, así como evaluar las implicaciones para la seguridad del paciente. MÉTODO: fue realizada una revisión de literatura de tipo integradora, con búsqueda en las bases de datos Pubmed/Medline, LILACS, SciELO y Biblioteca Cochrane, utilizando los descriptores interruptions y patient safety. La fecha inicial no fue limitada y la fecha final fue 31 de diciembre de 2013, se identificaron 29 artículos que atendieran a los criterios de inclusión. RESULTADOS: todos los artículos revisados describieron la interrupción como un factor perjudicial a la seguridad del paciente. El análisis de estos estudios reveló tres categorías relevantes: características de la interrupción, implicaciones de la interrupción para la seguridad del paciente e intervenciones para minimizar las interrupciones. CONCLUSIÓN: la interrupción favorece la ocurrencia de errores en la salud. Así, se notó la necesidad de realizar nuevas investigaciones para comprender ese fenómeno y los efectos del mismo en la práctica clínica. .

Influence of rootstocks on growth, yield, fruit quality and leaf mineral element contents of pear cv. 'Santa Maria' in semi-arid conditions

BACKGROUND: Rootstocks play an essential role to determining orchard performance of fruit trees. Pyrus communisand Cydonia oblonga are widely used rootstocks for European pear cultivars. The lack of rootstocks adapted to different soil conditions and different grafted cultivars is widely acknowledged in pear culture. Cydonia rootstocks (clonal) and Pyrus rootstocks (seedling or clonal) have their advantages and disadvantages. In each case, site-specific environmental characteristics, specific cultivar response and production objectives must be considered before choosing the best rootstock. In this study, the influence of three Quince (BA 29, Quince A = MA, Quince C = MC) and a local European pear seedling rootstocks on the scion yield, some fruit quality characteristics and leaf macro (N, P, K, Ca and Mg) and micro element (Fe, Zn, Cu, Mn and B) content of 'Santa Maria' pear (Pyrus communis L.) were investigated. RESULTS: Trees on seedling rootstock had the highest annual yield, highest cumulative yield (kg tree(-1)), largest trunk cross-sectional area (TCSA), lowest yield efficiency and lowest cumulative yield (ton ha(-1)) in the 10th year after planting. The rootstocks had no significant effect on average fruit weight and fruit volume. Significantly higher fruit firmness was obtained on BA 29 and Quince A. The effect of rootstocks on the mineral element accumulation (N, K, Ca, Mg, Fe, Zn, Cu, Mn and B) was significant. Leaf analysis showed that rootstocks used had different mineral uptake efficiencies throughout the early season. CONCLUSION: The results showed that the rootstocks strongly affected fruit yield, fruit quality and leaf mineral element uptake of 'Santa Maria' pear cultivar. Pear seedling and BA 29 rootstock found to be more prominent in terms of several characteristics for 'Santa Maria' pear cultivar that is grown in highly calcareous soil in semi-arid climate conditions. We determined the highest N, P (although insignificant), K, Ca, Mg, Fe and Cu mineral element concentrations on the pear seedling and BA 29 rootstocks. According to the results, we recommend the seedling rootstock for normal density plantings (400 trees ha(-1)) and BA 29 rootstock for high-density plantings (800 trees ha(-1)) for 'Santa Maria' pear cultivar in semi-arid conditions.

Isolation and characterization of osmotolerant bacteria from Thar Desert of Western Rajasthan (India)

The Thar Desert harsher environment harbors a limited diversity of life forms due to extreme conditions like low moisture of sandy soils and high soil temperature. In the present study, osmotolerant bacteria from the Thar soils were isolated and characterized. Bacteria were isolated from 20 soil samples (100g), collected from sand dunes, suspended in water and absolute alcohol. A total of 11 biochemical and morphological tests were carried out for generic identification of bacteria. Osmotic tolerance capacity of isolates was examined on glycerol, NaCl and alcohol; and sequencing of 16S rRNA gene was also performed for bacterial identification. 16S to 23S rRNA internal transcribed spacer analysis (RISA) was done for phylogenetic analysis of isolates. The soil suspended in water contained 2.5×10(6) bacteria/g of soil while alcohol suspended soil had 4.4×10(4) bacteria/g. The 24 bacterial isolates were found tolerant to 26% glycerol, 14% NaCl and 10% of alcohol, and 22 out of 24 isolates were found Gram positive. The results showed that 45.83% and 41.67% bacteria belong to Bacillus spp. and Corynebacterium spp., respectively, while Acinetobacter spp., Aeromonas spp. and Staphylococcus spp. were in equal proportion (4.16% each). Six isolates were selected for 16S rRNA gene sequencing and five were found 95% similar with Bacillus licheniformis whereas one isolate was identified as B. subtilis. All the isolates showed good growth up to 50°C with gradual reduction on subsequent increment of temperature. Out of 24 isolates, six could survive at 65°C while one isolate could grow at 63°C. Growth kinetic studies revealed that the reduction in generation time in solute(s) and temperature stress was more as compared to generation time in plain medium. This study suggests that virgin sand dunes may be a rich source of bacteria, tolerant to osmotrophic solutes, and can be examined for plant growth promotion activity in agriculture. Moreover, study might help to resolve the tactic adopted by microbes to defeat desiccation induced by various types of solutes.

El duro ambiente del desierto de Thar alberga una diversidad de formas de vida limitado debido a sus condiciones extremas, como el bajo contenido de humedad de los suelos arenosos y la alta temperatura del suelo. En el presente estudio, las bacterias osmotolerantes de los suelos de Thar, fueron aislados y caracterizados. Las bacterias fueron aisladas a partir de 20 muestras de suelo (100g), obtenidas de dunas de arena, suspendidas en agua y alcohol absoluto. Un total de 11 pruebas bioquímicas y morfológicas se llevaron a cabo para identificar géneros de bacterias: la capacidad de tolerancia osmótica de los aislados se examinó con glicerol, NaCl y alcohol, y la secuenciación de los genes 16S rRNA se realizó también para la identificación bacteriana. El análisis de espaciadores internos transcritos de 16S a 23S rRNA (RISA) se realizó para los aislamientos de análisis filogenéticos. El suelo suspendido en el agua contuvo 2.5×10(6) bacteria/g de suelo mientras que el suelo con alcohol suspendido presentó 4.4×104 bacteria/g. Los 24 aislados bacterianos se encontraron tolerantes a 26% glicerol, 14% NaCl y 10% de alcohol y 22 de los 24 aislados fueron grampositivas. Los resultados mostraron que 45.83% y 41.67% de las bacterias son Bacillus spp. y Corynebacterium spp., respectivamente, mientras que Acinetobacter spp., Aeromonas spp. y Staphylococcus spp. se presentaron en la misma proporción (4.16% cada uno). Seis aislamientos fueron seleccionados para secuenciación de genes 16S rRNA y 95% fueron similares a Bacillus licheniformis mientras que un aislamiento fue identificado como B. subtilis. Todos los aislamientos mostraron un buen crecimiento a 50º C con reducción gradual en el incremento subsiguiente de la temperatura. Fuera de 24 aislados, 6 podrían sobrevivir a 65ºC mientras que un aislado podría crecer a 63ºC. Estudios de crecimiento cinéticos revelaron que la reducción en el tiempo de generación en soluto (s) y estrés de temperatura fue mayor en comparación con el tiempo de generación en un medio simple. Este estudio sugiere que las dunas de arena virgen pueden ser una fuente rica de bacterias, tolerantes a los solutos osmotróficos y se pueden examinar para la promoción de crecimiento de plantas en la agricultura. Por otra parte, el estudio podría ayudar a resolver la táctica adoptada por los microorganismos para rechazar la desecación inducida por diversos tipos de solutos.

Combining molecular-marker and chemical analysis of Capparis deciduas (Capparaceae) in the Thar Desert of Western Rajasthan (India)

The Thar Desert, a very inhospitable place, accommodates only plant species that survive acute drought, unpredictable precipitation, and those can grow in the limited moisture of sandy soils. Capparis decidua is among one of the few plants able to grow well under these conditions. This species is highly exploited and has been naturally taken, as local people use it for various purposes like food, timber and fuel, although, no management or conservation efforts have been established. The present study was conducted in this arid area of Western Rajasthan (India) with the aim to obtain preliminary molecular information about this group of plants. We evaluated diversity among 46 samples of C. decidua using chemical parameters and random amplified polymorphic DNA (RAPD) markers. Fourteen chemical parameters and eight minerals (total 22 variables) of this species fruits were estimated. A total of 14 RAPD primers produced 235 band positions, of which 81.27% were polymorphic. Jaccard s similarity coefficients for RAPD primers ranged from 0.34 to 0.86 with a mean genetic similarity of 0.50. As per observed coefficient of variation, NDF (Neutral Detergent Fiber) content was found to be the most variable trait followed by starch and soluble carbohydrate. The Manhattan dissimilarity coefficient values for chemical parameters ranged between 0.02-0.31 with an average of 0.092. The present study revealed a very low correlation (0.01) between chemical parameters and RAPD-based matrices. The low correlation between chemical- and RAPD-based matrices indicated that the two methods were different and highly variable. The chemical-based diversity will assist in selection of nutritionally rich samples for medicinal purpose, while genetic diversity to face natural challenges and find sustainable ways to promote conservation for future use.

El desierto de Thar, un lugar muy inhóspito, alberga sólo a las especies de plantas capaces de resistir a condiciones de sequía extrema, a las precipitaciones impredecibles, y a las plantas que pueden crecer en la humedad limitada de los suelos arenosos. Capparis decidua se encuentra entre una las pocas plantas capaces de crecer bien en estas condiciones. Esta especie es altamente explotada y se ha tomado de forma natural, así los habitantes locales las han usado para varios propósitos, como alimento, madera y combustible, aunque sin ningún programa de manejo o esfuerzo por conservación. El presente estudio se llevó a cabo en esta zona árida del oeste de Rajastán (India) con el objetivo de obtener información molecular preliminar sobre este grupo de plantas. Se evaluó la diversidad entre 46 muestras de C. decidua usando parámetros químicos y marcadores de ADN polimórfico amplificado al azar (RAPD por sus siglas en inglés). Catorce parámetros químicos y ocho minerales (22 variables en total) de los frutos de esta especie fueron estimados. Un total de 14 cebadores para RAPD produjeron 235 posiciones de bandas, de las cuales 81.27% fueron polimórficas. El coeficiente de similitud de Jaccard para los cebadores del RAPD varió entre 0.34 y 0.86 con un promedio de similitud genética de 0.50. De acuerdo con el coeficiente de variación observado, se encontró que el contenido de NDF fue el rasgo más variable, seguido por el almidón y los carbohidratos solubles. Los valores del coeficiente de disimilitud de Manhattan para los parámetros químicos osciló entre 0.02-0.31 con un promedio de 0.092. El presente estudio reveló una correlación muy baja (0.01) entre los parámetros químicos y las matrices basadas en RAPD. La baja correlación entre las matrices químicas y la basada en RAPD indicó que los dos métodos fueron diferentes y altamente variables. El estudio de la diversidad basada en su química ayudará en la selección de muestras nutricionalmente ricas para fines medicinales, mientras que la diversidad genética ayudará a enfrentar los desafíos naturales y encontrar formas sostenibles para promover la conservación de esta plana para uso futuro.

Zooplankton assemblages in eutrophic reservoirs of the Brazilian semi-arid / Assembléias zooplanctônicas em reservatórios eutróficos do semiárido brasileiro

Species composition, density, and temporal dynamics of zooplankton were studied in six reservoirs in a semi-arid region in tropical northeastern Brazil (Rio Grande do Norte state). All the reservoirs are highly eutrophic, with high contents of total nitrogen (minimum of 1200 µg.L-1) and total phosphorus (minimum of 10 µg.L-1), and extremely high algal biomass was registered (surpassing 20 µg Chl a.L-1). All the reservoirs showed an enduring condition of high turbidity and phytoplankton assemblages dominated by cyanobacteria. Zooplankton also showed quantitative patterns suggestive of eutrophic conditions, expressed by high densities, mainly in Passagem das Traíras and Sabugi reservoirs. A spatial differentiation in the composition of the zooplankton community was registered. Rotifers (especially Keratella tropica, Brachionus havanensis, and Keratella americana) were the dominant forms in the zooplankton community of Itans, Passagem das Traíras, and Sabugi reservoirs, while calanoid copepods (mainly Notodiaptomus cearensis) dominated in the Armando Ribeiro, Gargalheiras, and Parelhas systems. The existence of novel relationships in zooplankton community composition in eutrophic reservoirs in this tropical semi-arid region must be considered in designating zooplankton indicators of eutrophic conditions.

A composição de espécies, a densidade e a dinâmica temporal do zooplâncton foram estudadas em seis reservatórios de uma região semiárida no nordeste do Brasil (Estado do Rio Grande do Norte). Todos os reservatórios estão altamente eutróficos, com altas concentrações de nitrogênio total (mínimo de 1.200 µg.L-1) e fósforo total (mínimo de 10 µg.L-1), e biomassa algal extremamente alta (muitas vezes, superando 20 µg.L-1 de Chl a). Todos os reservatórios apresentaram alta turbidez e assembleias fitoplanctônicas dominadas por cianobactérias. O zooplâncton também apresentou padrões quantitativos sugestivos de condições eutróficas, expressas por altas densidades, principalmente nos Reservatórios Passagem das Traíras e Sabugi. Foi registrada uma diferenciação espacial na composição da comunidade zooplanctônica. Rotíferos (especialmente Keratella tropica, Brachionus havanensis e Keratella americana) foram as formas dominantes na comunidade zooplanctônica dos Reservatórios Itans, Passagem das Traíras e Sabugi, enquanto copépodos Calanoida (principalmente Notodiaptomus cearensis) dominaram nos Reservatórios Armando Ribeiro Gonçalves, Gargalheiras e Parelhas. A existência de novas relações na composição da comunidade zooplanctônica em reservatórios eutróficos dessa região semiárida tropical deve ser considerada no estabelecimento de indicadores zooplanctônicos de condições eutróficas.

Separation and identification of endophytic fungi from desert plant Cynanchum komarovii / 中国中药杂志

<p><b>OBJECTIVE</b>The research aimed to investigate the entophytic fungal community of Cynanchum Komarrovii, including the biodiversity in different organs and the correlations with ecological environment. Endophytic fungi with patent bioactivity were also rapidly screened.</p><p><b>METHOD</b>PDA medium was used to isolate and purify the endophytic fungi from C. komarovii living in Shaanxi and Ningxia district, respectively. The strains were identified based on the morphological characteristics of the fungi and similarity of 5.8S gene and internal transcribed spacer (ITS) sequence. Pyriculaia oryzae model was applied to preliminarily screen the active fungi.</p><p><b>RESULT</b>Ninety-four strains of endophytic fungi were isolated and identified to 9 species, 13 genera, 9 families and 6 orders, among them, 47 strains were from the plants living in Ningxia. And then, 5 of them were isolated from roots, 14 from branches, and 28 from leaves. They were identified belonging to 8 species, 9 genera, 5 families and 4 orders. Additionally, 47 strains were from the plants living in Shaanxi. 16 were isolated from the roots, 18 from branches, 13 from leaves. They were identified belonging to 5 species, 8 genera, 6 families and 4 orders. By preliminary screening, 18 strains of endophytes completely inhibited the germination of conidium, which showed a potential bioactivity for these fungi. Both N4 and S17 strains had stronger growth inhibition effect.</p><p><b>CONCLUSION</b>Endophytic fungi from desert plant C. komarovii have the feature of diversity. Different geographical environment and type of organizations lead to the significant difference on the quantity and the species composition. Most of fungi in Ningxia C. komarovii distribute in leaves. However, most of those in Shaanxi C. komarovii distribute in stems and leaves. It also indicated that endophytes from C. komarovii had a strong antifungal activity.</p>

Chemical constituents from stems of Cistanche deserticola cultured in Tarim desert / 中国中药杂志

In order to clarify the chemical constituents of Cistanche deserticola cultured in Tarim desert, a systematically phytochemical investigation was carried out. The chemical constituents were isolated by column chromatography, over silica gel, Sephadex LH-20, MCI gel, ODS and semi-preparative HPLC, and their structures were determined on the basis of MS, NMR spectroscopic data analysis, physicochemical properties and/or comparison with literature data Seventeen compounds were isolated from the 85% ethanol extract of the stems of C. deserticola cultured in Tarim desert. Their structures were identified as salsaside B (1), syringin (2), demethyl syrinyin (3), coniferin (4), (2E,6E)-3,7-dimethyl-8-hydroxyoctadien-1-O-beta-D-glucoside (5), (+)-syringaresinol (6), 2S,3S, 4S-trihydroxypentanoic acid (7), panaxytriol (8), beta-sitosterol-3-O-beta-D-xylopyranoside (9), androsin (10), 3-methyl-but-2-en-1-yl-beta-D-glucopyranoside (11), benzyl-glucopyranoside (12), 4-hydroxybenzyl-beta-D-glucoside (13), nicotinamide (14), p-hydroxybenzoic acid (15), 4-hydroxy-benzeneethanol (16), and galactitol (17). Compounds 3, 6-13 were isolated from this genus for the first time, and compounds 1, 4 and 5 were obtained from this species for the first time.

Chemical and genetic diversity among some wild stands of Calligonum polygonoides (Polygonaceae) from the Thar Desert of Rajasthan

The arid Western Rajasthan, where the Thar Desert of India is immersed, is mostly covered by sand dunes, a common landscape. The region has confronted with fragilities of natural resources, low, erratic and ill-distributed rainfall, and is covered up with many perennial hardy shrubs. Calligonum polygonoides, the most common perennial shrub, is widely present in some localities of this Thar Desert. In this study, we evaluated the diversity present among 54 wild Calligonum polygonoides plants, sampled from eight different locations within the Thar Desert. Our methods included chemical/nutritional characteristics and random amplified polymorphic DNA (RAPD). Both chemical and molecular methods produced wider range of diversity, however, RAPD detected comparatively more diversity. A total of 163 band positions were produced by ten RAPD primers, of which 147 were found polymorphic with 90.18% polymorphism. RAPD-based Jaccard’s similarity coefficients ranged from 0.43-0.89. The analysis of various chemical and mineral constituents revealed that phog is an excellent source of calcium, potassium and phosphorous while relatively poor in zinc. Among minerals, average potassium content was found maximum (2 430mg/100g) with 0.14 CV. Zinc was observed comparably less in quantity while highest variable with CV 0.73. The chemical-based Manhattan dissimilarity coefficient values ranged from 0.01-0.22 with an average of 0.12. The comparison of the clusters obtained based on the chemical and mineral parameters with those of the RAPD data showed that the groups formed in both cases showed different patterns of relationships among the samples. Broader range of diversity might be due to the out breeding behavior of C. polygonoides and indicates the good adaptability of the plants in the region studied. However, low diversity observed in the Bikaner province is alarming and suggests that anthropogenic activities leading to heavy population disturbances can affect the genetic composition of the species in a considerable way.

El árido Rajastán occidental, en donde está inmerso el desierto de Thar en la India, está cubierto principalmente por dunas de arena, un paisaje común. La región ha enfrentado la fragilidad de los recursos naturales, las lluvias escasas, irregulares y mala distribución, y está cubierta con muchos arbustos resistentes perennes. Calligonum polygonoides, el arbusto perenne más común, se encuentra ampliamente en algunas localidades del desierto de Thar. En este estudio, se evaluó la diversidad presente entre 54 plantas silvestres de Calligonum polygonoides, de ocho localidades diferentes del desierto de Thar. Nuestros métodos incluyen características químicas/nutricionales y ADN polimórfico amplificado (RAPD) al azar. Ambos métodos químicos y moleculares producen un amplio rango de la diversidad, sin embargo, RAPD detectó comparativamente mayor diversidad. Un total de 163 posiciones de la banda fueron producidos por diez cebadores RAPD, de los cuales 147 se encontraron polimórficos con un 90.18% de polimorfismo. El coeficiente de RAPD basado en la similitud de Jaccard varió desde 0.43 hasta 0.89. El análisis de varios constituyentes químicos y minerales reveló que Calligonum polygonoides es una excelente fuente de calcio, potasio y fósforo mientras que es relativamente pobre en zinc. Entre los minerales, el contenido de potasio promedio se encontró como máximo (2 430mg/100g), con 0.14 CV. El zinc se observó comparativamente menor en cantidad, pero presentó la mayor variabilidad con CV 0.73. El valor del coefficente de disimilitud de Manhattan varió en un rango de 0.01 hasta 0.22 con un promedio de 0.12. La comparación de los grupos obtenidos según los parámetros químicos y minerales con las de los datos de RAPD mostró que los grupos formados en ambos casos mostraron patrones diferentes de relaciones entre las muestras. Una gama más amplia de la diversidad podría ser debido al comportamiento reproductivo C polygonoides e indica la buena adaptabilidad ...

Seasonal dynamics of cyanobacteria in a eutrophic reservoir (Arcoverde) in a semi-arid region of Brazil / Dinâmica sazonal de cianobactérias em um reservatório eutrófico (Arcoverde) no semiárido brasileiro

Environmental conditions favor the predominance of dense populations of cyanobacteria in reservoirs in northeastern Brazil. The aim of this study was to understand cyanobacterial population dynamics in the rainy and dry seasons at two depths in the Arcoverde reservoir. Microalgae and cyanobacteria samples were collected during 24 hours with intervals of 4 hours (nycthemeral) at sub-surface and 10 m using a van Dorn bottle and a determined biomass. Physical and chemical variables were obtained and the data were analyzed using the principal component analysis (PCA). No nycthemeral variations in the taxonomic composition or distribution of the populations of cyanobacteria were found between the different times of day in either the rainy or dry season. In both seasons, the greatest biomass of the phytoplankton community was made up of cyanobacteria at two depths and all times of the day. Cylindrospermopsis raciborskii (Woloszynska) Seenayya et Subba Raju was dominant at all times of the day on both the surface and at the bottom. In the rainy season, the differences in cyanobacterial biomass between the surface and bottom were less significant than in the dry season. The differences in cyanobacterial biomass between surface and bottom were less pronounced than those found in the dry season. We concluded that a) physical variables better explain the alterations of species in the phytoplankton community in an environment dominated by cyanobacteria throughout the year; b) seasonal climatic factors associated to periods of stratification and de-stratification are important for alterations in the community and variations in biomass and, c) the turbidity caused by rainfall favored the emergence and establishment of other cyanobacteria, especially Planktothrix agardhii (Gomont) Anagnostidis & Komárek.

As condições ambientais favorecem a predominância de populações densas de cianobactérias no nordeste do Brasil. O objetivo deste estudo foi entender a dinâmica das populações de cianobactérias nas estações seca e chuvosa, em duas profundidades, no reservatório de Arcoverde. Amostras de microalgas e cianobactérias foram coletadas durante 24 horas em intervalos de quatro horas (nictemerais) na subsuperfície e em 10 m, com uma garrafa de van Dorn, para a determinação da biomassa. Variáveis físicas e químicas foram obtidas, e os dados investigados por meio da Análise de Componentes Principais (ACP). Não foram encontradas variações nictemerais na composição taxonômica ou na distribuição das populações de cianobactérias entre os diferentes horários do dia, bem como entre as estações seca e chuvosa. Em ambas as estações, horários do dia e profundidades amostrais, a maior biomassa da comunidade fitoplanctônica foi constituída por cianobactérias. Cylindrospermopsis raciborskii (Woloszynska) Seenayya et Subba Raju foi dominante em todos os horários do dia, tanto na superfície como no fundo. Na estação chuvosa, as diferenças de biomassa de cianobactérias entre superfície e fundo foram menos pronunciadas do que na estação seca. Concluímos que: a) variáveis físicas explicam melhor as alterações das espécies na comunidade fitoplanctônica em um ambiente dominado por cianobactérias durante todo o ano; b) fatores climáticos sazonais associados a períodos de estratificação e desestratificação são importantes para as alterações na comunidade e as variações na biomassa, e c) a turbidez causada pela chuva favoreceu o aparecimento e o estabelecimento de outras cianobactérias, especialmente Planktothrix agardhii (Gomont) Anagnostidis & Komárek.

Prosopis laevigata and Mimosa biuncifera (Leguminosae), jointly influence plant diversity and soil fertility of a Mexican semiarid ecosystem

Prosopis laevigata and Mimosa biuncifera are frequently found in arid and semiarid shrublands, but scarce information is available about their influence on plant community structure and soil fertility. We compared plant community structure, diversity and soil nutrients of three semiarid shrubland sites located in Mezquital Valley, Mexico. These sites differ in their dominant species: Site 1 (Bingu) P. laevigata, Site 2 (González) M. biuncifera, and Site 3 (Rincón) with the presence of both legumes. The results showed that the plant community with P. laevigata and M. biuncifera (Site 3) had more cover, taller plants and higher plant diversity than sites with only one legume (Site 1 and Site 2). Soil organic matter (SOM), soil organic carbon (SOC), total nitrogen (TN), phosphorus-Olsen (P) and C mineralization were higher in the soil under the canopy of both legumes than in bare soil. In contrast, soil cation concentrations were lower under the canopy of P. laevigata, but not for M. biuncifera. In addition, the density of arbuscular mycorrhizal fungi spores was higher within the soil under the canopy of M. biuncifera than in the soil under the canopy of P. laevigata. Thus, resource islands (RI) created by P. laevigata increased the amounts of SOC, TN and P when compared with the RI of M. biuncifera. This study provided evidences about the importance of species identity in order to expand the niche availability for the establishment of other plants, and highlights that P. laevigata and M. biuncifera jointly influencing plant colonization within semiarid ecosystems.

Prosopis laevigata y Mimosa biuncifera coexisten en los matorrales semiáridos; sin embargo, se desconoce su influencia sobre la diversidad de la comunidad vegetal y el suelo. Este estudio evaluó el efecto de P. laevigata y M. biuncifera sobre la estructura, diversidad vegetal y nutrimentos del suelo, en tres matorrales del Valle del Mezquital, México. Los sitios difieren en la especie dominante: Sitio 1, P. laevigata; Sitio 2, M. biuncifera y Sitio 3, ambas leguminosas. En cada sitio se recolectó suelo, tanto abajo y fuera del dosel de las leguminosas, además, se realizaron transectos para medir e identificar las plantas arbóreas y arbustivas, se calculó el índice de valor de importancia y la diversidad del matorral. Asimismo, se registró mayor riqueza y diversidad en el Sitio 3 (ICE 29 spp. y H’ 2.7), en comparación con el Sitio 1 (24 spp. y 2.4) y Sitio 2 (26 spp. y 2.1). La materia orgánica y el carbono orgánico del suelo, así como el N total, el P-Olsen y la mineralización de C fueron mayores en el suelo bajo dosel de ambas leguminosas. La abundancia de esporas de hongos micorrizógenos arbusculares fue favorecida por M. biunficera. La influencia de P. laevigata para crear islas más ricas en recursos fue mayor que en M. biunficera, lo anterior sugiere que cada leguminosa modifica de una forma diferente el microambiente, sin embargo, juntas aumentan la disponibilidad de nichos para el establecimiento de otras especies, lo queayuda a comprender el papel de P. laevigata y M. biuncifera sobre la colonización vegetal en ecosistemas semiáridos.

Germination of three wheat varieties under equipotential levels of matric [vm] and osmotic [vs] stress

Choice of a crop plant to be suitable for cultivation in desert areas must be within some considerations. Desert areas are generally characterized by: [I] lack of water, [2] climatic extremes, [3] several wide deficiencies in nutrient elements, [4] salinity and ion toxicity problems and [5] interaction between one or more of such previous factors. In this work, the response of three wheat varieties [Sids 1, Sakha 93 and Glza 168] to major environmental hazards existing in desert habitats is accounted for. Besides, the combined effects of temperature, matric or osmotic water potentials under different temperatures on different germination characteristics are studied. The study is concerned with both the germination stage and the early seedling stage to ensure success of the vegetative growth later. In most cases, temperature as a single factor had the dominant effect on germination characteristics