scholarly journals Phytophthora Species in Rivers and Streams of the Southwestern United States

2016 ◽  
Vol 82 (15) ◽  
pp. 4696-4704 ◽  
Author(s):  
Rio A. Stamler ◽  
Soumalia Sanogo ◽  
Natalie P. Goldberg ◽  
Jennifer J. Randall
Keyword(s):  
United States ◽  
Plant Pathogens ◽  
Rio Grande ◽  
Phytophthora Species ◽  
Southwestern United States ◽  
Content Type ◽  
Rivers And Streams ◽  
San Juan River ◽  
Rio Grande River ◽  
Prevalent Species

ABSTRACTPhytophthoraspecies were isolated from rivers and streams in the southwestern United States by leaf baiting and identified by sequence analysis of internal transcribed spacer (ITS) ribosomal DNA (rDNA). The major waterways examined included the Rio Grande River, Gila River, Colorado River, and San Juan River. The most prevalent species identified in rivers and streams werePhytophthora lacustrisandP. riparia, both members ofPhytophthoraITS clade 6.P. gonapodyides,P. cinnamomi, and an uncharacterizedPhytophthoraspecies in clade 9 were also recovered. In addition, six isolates recovered from the Rio Grande River were shown to be hybrids ofP. lacustris×P. riparia. Pathogenicity assays usingP. ripariaandP. lacustrisfailed to produce any disease symptoms on commonly grown crops in the southwestern United States. Inoculation ofCapsicum annuumwithP. ripariawas shown to inhibit disease symptom development when subsequently challenged withP. capsici, a pathogenicPhytophthoraspecies.IMPORTANCEManyPhytophthoraspecies are significant plant pathogens causing disease on a large variety of crops worldwide. Closer examinations of streams, rivers, and forest soils have also identified numerousPhytophthoraspecies that do not appear to be phytopathogens and likely act as early saprophytes in aquatic and saturated environments. To date, thePhytophthoraspecies composition in rivers and streams of the southwestern United States has not been evaluated. This article details a study to determine the identity and prevalence ofPhytophthoraspecies in rivers and streams located in New Mexico, Arizona, Colorado, Utah, and Texas. Isolated species were evaluated for pathogenicity on crop plants and for their potential to act as biological control agents.

scholarly journals Combining Uranium, Boron, and Strontium Isotope Ratios (234U/238U, δ11B, 87Sr/86Sr) to Trace and Quantify Salinity Contributions to Rio Grande River in Southwestern United States

2021 ◽  
Vol 2 ◽  
Author(s):  
Sandra Garcia ◽  
Pascale Louvat ◽  
Jerome Gaillardet ◽  
Syprose Nyachoti ◽  
Lin Ma
Keyword(s):  
United States ◽  
New Mexico ◽  
River Flow ◽  
Shallow Groundwater ◽  
Rio Grande ◽  
Isotope Ratios ◽  
Critical Zone ◽  
Southwestern United States ◽  
Isotopic Compositions ◽  
Rio Grande River

In semi-arid to arid regions, both anthropogenic sources (urban and agriculture) and deeper Critical Zone (groundwater with long flow paths and water residence times) may play an important role in controlling chemical exports to rivers. Here, we combined two anthropogenic isotope tracers: uranium isotope ratios (234U/238U) and boron isotope ratios (δ11B), with the 87Sr/86Sr ratios to identify and quantify multiple solute (salinity) sources in the Rio Grande river in southern New Mexico and western Texas. The Rio Grande river is a major source of freshwater for irrigation and municipal uses in southwestern United States. There has been a large disagreement about the dominant salinity sources to the Rio Grande and particularly significant sources are of anthropogenic (agriculture practices and shallow groundwater flows, groundwater pumping, and urban developments) and/or geological (natural groundwater upwelling) origins. Between 2014 and 2016, we collected monthly river samples at 15 locations along a 200-km stretch of the Rio Grande river from Elephant Butte Reservoir, New Mexico to El Paso, Texas, as well as water samples from agricultural canals and drains, urban effluents and drains, and groundwater wells. Our study shows that due to the presence of localized and multiple salinity inputs, total dissolved solids (TDS) and isotope ratios of U, B, and Sr in the Rio Grande river show high spatial and temporal variability. Several agricultural, urban, and geological sources of salinity in the Rio Grande watershed have characteristic and distinguishable U, Sr, and B isotope signatures. However, due to the common issue of overlapping signatures as identified by previous tracer studies (such as δ18O, δD, δ34S), no single isotope tracer of U, Sr, or B isotopes was powerful enough to distinguish multiple salinity sources. Here, combining the multiple U, Sr, and B isotope and elemental signatures, we applied a multi-tracer mass balance approach to quantify the relative contributions of water mass from the identified various salinity end members along the 200-km stretch of the Rio Grande during different river flow seasons. Our results show that during irrigation (high river flow) seasons, the Rio Grande had uniform chemical and isotopic compositions, similar to the Elephant Butte reservoir where water is stored and well-mixed, reflecting the dominant contribution from shallow Critical Zone in headwater regions in temperate southern Colorado and northern New Mexico. In non-irrigation (low flow) seasons when the river water is stored at Elephant Butte reservoir, the Rio Grande river at many downstream locations showed heterogeneous chemical and isotopic compositions, reflecting variable inputs from upwelling of groundwater (deeper CZ), displacement of shallow groundwater, agricultural return flows, and urban effluents. Our study highlights the needs of using multi-tracer approach to investigate multiple solutes and salinity sources in rivers with complex geology and human impacts.

Near-peer video-based feedback: a useful activity for aspiring school leaders?

2020 ◽  
Vol 9 (4) ◽  
pp. 357-373
Author(s):  
Wowek Sean Kearney ◽  
James Jurica ◽  
Theresa Entzi
Keyword(s):  
United States ◽  
Student Teaching ◽  
Undergraduate Students ◽  
School Leaders ◽  
Public University ◽  
Small Scale ◽  
Southwestern United States ◽  
Preparation Programs ◽  
Content Type ◽  
Aspiring Principals

PurposeThis study examined the value of using near-peer video-based feedback to help train aspiring school leaders in coaching strategies. This research is part of a larger study in which feedback was solicited from both aspiring teachers and aspiring school leaders. The current study focused on the responses provided by the aspiring school leaders.Design/methodology/approachThis study utilized a phenomenological design. Undergraduate students enrolled in a public university in the Southwestern United States were recorded delivering instruction during their final semester of student teaching. These videos were uploaded to a secure website using EdPuzzle. Graduate students aspiring to be principals who were enrolled in a supervision course at the same university observed these classroom videos and provided feedback.FindingsIn regard to what participants learned about using video recordings, responses of aspiring principals fell into three themes as follows: establishing trust, providing critical feedback and broadening perspectives.Research limitations/implicationsThis study is limited by it being a small-scale study conducted at one public university in the Southwestern United States. Accordingly, the findings of this study are limited in their generalizability.Practical implicationsThis study highlights the usefulness of collaborations between educator preparation programs and principal preparation programs to enhance the learning of both student groups.Originality/valueThis research adds to the small but growing body of literature regarding near-peer video-based feedback and its potential value in helping aspiring principals practice coaching skills using written feedback.

scholarly journals Multilaboratory Study of Epidemiological Cutoff Values for Detection of Resistance in Eight Candida Species to Fluconazole, Posaconazole, and Voriconazole

2014 ◽  
Vol 58 (4) ◽  
pp. 2006-2012 ◽  
Author(s):  
A. Espinel-Ingroff ◽  
M. A. Pfaller ◽  
B. Bustamante ◽  
E. Canton ◽  
A. Fothergill ◽  
...  
Keyword(s):  
United States ◽  
Candida Species ◽  
The United States ◽  
Broth Microdilution ◽  
Wild Type ◽  
Content Type ◽  
Cutoff Values ◽  
Prevalent Species ◽  
Single Laboratory

ABSTRACTAlthough epidemiological cutoff values (ECVs) have been established forCandidaspp. and the triazoles, they are based on MIC data from a single laboratory. We have established ECVs for eightCandidaspecies and fluconazole, posaconazole, and voriconazole based on wild-type (WT) MIC distributions for isolates ofC. albicans(n= 11,241 isolates),C. glabrata(7,538),C. parapsilosis(6,023),C. tropicalis(3,748),C. krusei(1,073),C. lusitaniae(574),C. guilliermondii(373), andC. dubliniensis(162). The 24-h CLSI broth microdilution MICs were collated from multiple laboratories (in Canada, Brazil, Europe, Mexico, Peru, and the United States). The ECVs for distributions originating from ≥6 laboratories, which included ≥95% of the modeled WT population, for fluconazole, posaconazole, and voriconazole were, respectively, 0.5, 0.06 and 0.03 μg/ml forC. albicans, 0.5, 0.25, and 0.03 μg/ml forC. dubliniensis, 8, 1, and 0.25 μg/ml forC. glabrata, 8, 0.5, and 0.12 μg/ml forC. guilliermondii, 32, 0.5, and 0.25 μg/ml forC. krusei, 1, 0.06, and 0.06 μg/ml forC. lusitaniae, 1, 0.25, and 0.03 μg/ml forC. parapsilosis, and 1, 0.12, and 0.06 μg/ml forC. tropicalis. The low number of MICs (<100) for other less prevalent species (C. famata,C. kefyr,C. orthopsilosis,C. rugosa) precluded ECV definition, but their MIC distributions are documented. Evaluation of our ECVs for some species/agent combinations using published individual MICs for 136 isolates (harboring mutations in or upregulation ofERG11,MDR1,CDR1, orCDR2) and 64 WT isolates indicated that our ECVs may be useful in distinguishing WT from non-WT isolates.

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