4,188 research outputs found
Evaluación de los efectos de la urbanización en los arroyos de Tierra del Fuego
We set out to understand how urbanization affects streams in Ushuaia, Tierra del Fuego. Paired ttestsand linear regressions were used to compare physico-chemical stream habitat variables (i.e., temperature,turbidity, conductivity, dissolved oxygen and pH) and benthic macroinvertebrate community structure (i.e.,density, taxonomic richness, Shannon-Weiner diversity) and function (functional feeding groups [FFG]) in fourwatersheds with urban and reference sites. We then calculated indices of biotic integrity for habitat (rapid visualassessment protocol [RVAP]) and benthos (Ephemeroptera, Plecoptera, Trichoptera richness [EPT], family bioticindex [FBI], rapid bioassessment protocol [RBP] and biotic monitoring Patagonian streams [BMPS]). Resultsindicated that urbanization negatively impacted these streams? underlying ecological condition, decreasingbenthic biodiversity and dissolved oxygen, while increasing conductivity and turbidity. FFG assemblagewas similar between both sites, but urbanization increased the existing dominance of collector-gatherers.Additionally, urban sites presented lower values in three of the benthic macroinvertebrate indices (EPT, RBP,BMPS, but not FBI) and also for habitat (RVAP). These data fill an existing gap in stream ecology for southernPatagonia and are useful to create monitoring tools. By incorporating urbanization as a driver of ecosystemchange, managers and planners will be better able to confront the issue of sustainable development in thisregion, which is considered one of the most pristine wilderness areas remaining on the planet but whosehuman population is concentrated in a few densely populated urban areas.Fil: Zagarola, Jean Paul A.. Bonneville Environmental Foundation; Estados UnidosFil: MartÃnez Pastur, Guillermo José. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro Austral de Investigaciones CientÃficas; ArgentinaFil: Lopez, MarÃa Eugenia. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro Austral de Investigaciones CientÃficas; ArgentinaFil: Anderson, Christopher Brian. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro Austral de Investigaciones CientÃficas; Argentin
Genomic analysis of eight native plasmids of the phytopathogen Pseudomonas syringae
Comunicación a conferenciaThe pPT23A family of plasmids (PFPs) appears to be indigenous to the plant pathogen Pseudomonas syringae and these plasmids are widely distributed and widely transferred among pathovars of P. syringae and related species. PFPs are sources of accessory genes for their hosts that can include genes important for virulence and epiphytic colonization of plant leaf surfaces. Further understanding of the evolution of the pPT23A plasmid family and the role of these plasmids in P. syringae biology and pathogenesis, requires the determination and analysis of additional complete, closed plasmid genome sequences. Therefore, our main objective was to obtain complete genome sequences from PFPs from three different P. syringae pathovars and perform a comparative genomic analysis. In this work plasmid DNA isolation, purification by CsCl-EtBr gradients, and sequencing using 454 platform, were used to obtain the complete sequence of P. syringae plasmids. Different bioinformatic tools were used to analyze the plasmid synteny, to identify virulence genes (i.e. type 3 effectors) and to unravel the evolutionary history of PFPs. Our sequence analysis revealed that PFPs from P. syringae encode suites of accessory genes that are selected at different levels (universal, interpathovar and intrapathovar). The conservation of type IVSS encoding conjugation functions also contributes to the distribution of these plasmids within P. syringae populations. Thus, this study contributes to unravel the genetic basis of the role of PFPs in different P. syringae lifestyles.Universidad de Málaga. Campus de Excelencia Internacional AndalucÃa Tech
Isolation, characterization and selection of bacterial isolates from a suppressive soil with beneficial traits to plants
Backgrounds
This study focused on the characterization and selection of bacterial strains obtained from a suppressive soil displaying antifungal activity against the soilborne phytopathogenic fungi Rosellinia necatrix. Bacterial profile from this suppressive soil were first obtained by 16S rRNA gene sequencing, revealing a significant increase in the bacterial class Gammaproteobacteria, especially in some antagonistic representatives of Pseudomonas spp.
Objectives
To obtain and characterize a collection of 246 bacterial isolates obtained from this suppressive soil, in order to identify new strains with antifungal activity against fungal phytopathogens.
Methods
To obtain the bacterial collection, we performed an isolation on a selective medium for Pseudomonas-like microorganisms. Further characterization tests were used in order to analyse the bacterial collection, including identification of the general metabolic profile of glucose, the profiling of antifungals produced, including both the putative production of antifungal compounds and lytic exoenzymes, and the evaluation of traits related with beneficial effects on plants.
Conclusions
A final selection of representative strains resulted in antifungal isolates belonging to the genus Pseudomonas, but also some representatives of the genera Serratia and Stenotrophomonas. These selected strains were tested for plant protection by an in vivo experiment using avocado and wheat plants challenged by the pathogen R. necatrix, showing all of them an antifungal ability and plant disease protection.
Pseudomonas-like strains isolated from suppressive soils constitute an excellent source for novel microbial biocontrol agents against soilborne fungal pathogens.
This work was supported by grant AGL2014-52518-C2-1-R. Carmen Vida and Sandra Tienda are supported by a PhD fellowship from the FPI program of the Spanish Government.This work was supported by grant AGL2014-52518-C2-1-R. Carmen Vida and Sandra Tienda are supported by a PhD fellowship from the FPI program of the Spanish Government; Universidad de Málaga. Campus de Excelencia Internacional AndalucÃa Tech
Comparative genomic analysis of native pseudomonas syringae plasmids belonging to the ppt23 a family reveals their role in p. Syringae epiphytic and pathogenic lifestyles
Backgrounds
The pPT23A family of plasmids (PFPs) appears to be indigenous to the plant pathogen Pseudomonas syringae and these plasmids are widely distributed and widely transferred among pathovars of P. syringae and related species. PFPs are sources of accessory genes for their hosts that can include genes important for virulence and epiphytic colonization of plant leaf surfaces.
Objectives
Further understanding of the evolution of the pPT23A plasmid family and the role of these plasmids in P. syringae biology and pathogenesis, requires the determination and analysis of additional complete, closed plasmid genome sequences. Therefore, our main objective was to obtain complete genome sequences of PFPs from three different P. syringae pathovars and perform a comprehensive comparative genomic analysis.
Methods
In this work plasmid DNA isolation, purification by CsCl-EtBr gradients, and sequencing using 454 platform, were carried out to obtain the complete sequence of P. syringae plasmids. Different bioinformatic tools were used to analyze the plasmid synteny, to identify virulence genes (i.e. type 3 effectors) and to unravel the evolutionary history of PFPs.
Conclusions
Our sequence analysis revealed that PFPs from P. syringae encode suites of accessory genes that are selected at different levels (universal, interpathovar and intrapathovar). The conservation of type IVSS encoding conjugation functions also contributes to the distribution of these plasmids within P. syringae populations. Thus, this study contributes to unravel the genetic bases of the role of PFPs in different P. syringae lifestyles.
This work was supported by grants Proyecto de Excelencia, Junta de AndalucÃa (P07-AGR-02471; P12-AGR-1473) and by Michigan State University AgBioResearch.This work was supported by grants Proyecto de Excelencia, Junta de AndalucÃa (P07-AGR-02471; P12-AGR-1473) and by Michigan State University AgBioResearch; Universidad de Málaga. Campus de Excelencia Internacional AndalucÃa Tech
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Barriers to Curricular Decentralization of an Urban School System: A Process Model for the Implementation of Site Based Management
The problem of this study is to identify and describe specific bureaucratic/organizational barriers that inhibit needed curricular and instructional flexibility and freedom in an urban school system and to determine if means exist by which the barriers can be overcome. The purposes of this study include the identification, description, and assessment of the barriers identified and the development of a process model which addresses identified barriers. The study includes samples of parents, teachers, principals, and central administrators. Questionnaires were administered to parents and teachers. Structured interviews were conducted with all administrators. The survey instruments were validated through means of pilot tests and jury panels
Surgical approach for cardiac surgery in a patient with tracheostoma
The thoracic approach for cardiac surgery in a patient with a tracheostoma can
result in difficult problems, such as mediastinitis, stoma necrosis or inadequate
operative exposure. We present a distinct approach consisting of an incision at
the second intercostal space, transverse sternum transection and longitudinal
median sternotomy to the xiphoid process, performed for coronary artery bypass
grafting and aortic valve replacement, in a patient with previous tracheotomy.
This approach permitted adequate surgical exposure for cardiopulmonary bypass,
aortic valve replacement and coronary revascularization procedures
Oxygen in metabolic dysfunction and its therapeutic relevance
Significance: In recent years, a number of studies have shown altered oxygen partial pressure at a tissue level in metabolic disorders, and some researchers have considered oxygen to be a (macro) nutrient. Oxygen availability may be compromised in obesity and several other metabolism-related pathological conditions, including sleep apnea-hypopnea syndrome, the metabolic syndrome (which is a set of conditions), type 2 diabetes, cardiovascular disease, and cancer. Recent Advances: Strategies designed to reduce adiposity and its accompanying disorders have been mainly centered on nutritional interventions and physical activity programs. However, novel therapies are needed since these approaches have not been sufficient to counteract the worldwide increasing rates of metabolic disorders. In this regard, intermittent hypoxia training and hyperoxia could be potential treatments through oxygen-related adaptations. Moreover, living at a high altitude may have a protective effect against the development of abnormal metabolic conditions. In addition, oxygen delivery systems may be of therapeutic value for supplying the tissue-specific oxygen requirements. Critical Issues: Precise in vivo methods to measure oxygenation are vital to disentangle some of the controversies related to this research area. Further, it is evident that there is a growing need for novel in vitro models to study the potential pathways involved in metabolic dysfunction to find appropriate therapeutic targets. Future Directions: Based on the existing evidence, it is suggested that oxygen availability has a key role in obesity and its related comorbidities. Oxygen should be considered in relation to potential therapeutic strategies in the treatment and prevention of metabolic disorders
Is it possible to store spotted wolffish (Anarhichas minor) sperm by refrigeration?
Spotted wolffish Anarhichas minor reproduction in captivity is dependent on in vitro fertilization. However, it is often challenging to acquire sufficient fresh sperm to fertilize the eggs that are obtained. In this study, we evaluate the possibility to store spotted wolffish sperm by refrigeration. Spotted wolffish sperm has the particularity that is already motile on stripping, and currently it is not possible to immobilize and reactivate. Thus, sperm refrigeration protocols should focus in extending this motility period that usually lasts up to 2 days. In a first experiment, we evaluated the possibility that the motility period of the sperm was limited by contamination with urine. The urea concentration in the sperm obtained both by stripping (17.10 ± 1.98 mg/dL) and directly from the testis (12.59 ± 2.37 mg/dL) was similar (p > 0.05), which indicate that the sperm collection method used avoid contamination with urine. Afterwards, we tested the possibility that the sperm motility period was limited by energy stores. The ATP concentration (initial value 5.65 ± 0.86 nmol/109 cells) remained stable (p = 0.099) during 30 h after sperm collection, and similar values (p = 0.329) were recorded at end of sperm storage in both diluted (3.88 ± 1.35 nmol/109 cells) and undiluted samples (4.76 ± 1.08 nmol/109). This indicates that the low intracellular ATP consumption, derived from the slow sperm motility, can probably be compensated rapidly enough by mitochondrial synthesis of ATP in the spotted wolffish sperm. In both experiments, diluted sperm kept higher percentage of motile cells during the storage time.publishedVersionUnit License Agreemen
Acneiform lesions secondary to ZD1839, an inhibitor of the epidermal growth factor receptor
Drugs that inhibit the epidermal growth factor receptor, such as ZD1839 or C225,
are being used increasingly in the treatment of solid tumours. This has led to
the appearance of new secondary effects. We describe the case of a patient who
presented with an acneiform eruption secondary to the administration of ZD1839.
These lesions healed in a few days after stopping the dru
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