Molecular and host specificity studies of Puccinia Striiformis in Australia

ABSTRACT The development of 26 SSR markers, specific for selective and sensitive amplification of Puccinia striiformis Westend forma specialis tritici Eriks (Pst), and related stripe rust pathogens, is documented. These markers were designed using genomic sequences from collaborators at the Australian National University and data published by Cantu et al. (2010). The allelic diversity observed varied from 2 to 8 alleles per locus and PIC values ranged from 0.5 to 0.76 with an average of 0.54. The marker set discriminated major Pst lineages in Australia, and separate host specific forms of the stripe rust pathogen on various graminaceous hosts. There was limited evidence for specific molecular phenotypes associating with Pst pathotypes. The SSR markers were able to identify a putative hybrid form of Pst, and were also used to develop a diagnostic test for application in biosecurity and incursion detection. The diagnostic protocol was based on simple and reliable visualisation using 3% agarose gel electrophoresis and was able to adequately amplify PCR products even with minute and degraded DNA samples from urediniospores and stripe rust infected leaf tissue. Fifteen of the SSR markers developed were used to genotype a set of 115 Australian isolates of Puccinia striiformis. The isolates were collected over the years 1979 – 2010 and represented 14 pathotypes from two major Pst pathotype lineages (pre-2002 and post-2002). Three isolates of Pst from the USA were also included. Genotyping was also performed for isolates of non-wheat infecting P. striiformis f. sp. pseudo-hordei and P. striiformis f. sp. hordei. Isolates of the stripe rust pathogens P. striiformoides (Psds) and P. pseudostriiformis (Pps), infecting cocksfoot grass (Dactylis glomerata) and Kentucky bluegrass (Poa pratensis), respectively, were also included. The results confirmed the clonal nature of the Pst population in Australia. Isolates from each of the two major Pst pathotype lineages were strongly clustered and pathotype demarcation beyond this point was limited. The USA isolates strongly resembled post-2002 isolates detected in Australia with limited additional variation between isolates from both continents. Distinct groupings, congruent with host preferences, were evident among the formae speciales Pst, Psp-h and Psh. However, many alleles were shared between the forms at various SSR loci, making intraspecific relationships difficult to resolve. The pathogens Psds and Pps were separated from Pst, Psp-h and Psh, largely due to extensive non-amplification of target product in isolates of Psds and Pps but also allelic polymorphism, when using the SSRs developed here from Pst genomic sequence data. This agrees with recent studies that have elevated both to species rank (Liu & Hambleton, 2010). The role of wild Hordeum Link spp. as an ancillary host of Pst in Australia was explored in this study. A differential set of Hordeum spp. was developed in order to examine avirulence/virulence characteristics of Pst isolates originating from cultivated cereals and weedy Hordeum communities. The differential set was used to screen isolates from a range of Pst pathotypes collected over a 30 year period and representing diverse geographical origins. Five distinct pathotypes were described with respect to the Hordeum differential set. The majority of Pst isolates derived from the original 1979 incursion and all isolates derived from the 2002 incursion were considered avirulent for Hordeum and were designated pathotype H1. Representative isolates collected between 1980 to 2001 showed evidence for increased virulence of Pst on Hordeum spp., classified as pathotypes H2 to H5. There was no association between the pathotypes determined using the Hordeum differential developed here and the pathotypes already established for these isolates using wheat differential lines. Therefore, weedy Hordeum spp, although widely distributed and frequently associated with commercial wheat production, were concluded to play a negligible selective role in the evolution of pathotype variability on wheat. However, susceptible genotypes of Hordeum spp. were frequently observed and these may assume a supporting role in Pst inoculum production and dispersal

Determining the Impact of Latitude on Parturition Timing in Captive North American River Otters: A Statistical Analysis of AZA Studbook Records

Historically, North American river otters (Lontra canadensis) were widely dispersed throughout the North American continent. Trapping pressures and urbanization have led to regional exclusion of North American river otter populations from historic habitats, leading the Association of Zoos and Aquariums to spearhead conservation and captive breeding efforts to maintain genetic diversity of the aquatic mustelid. Difficulties in consistently breeding captive North American river otters have spotlighted a need to understand how geography and life history of adult individuals influence reproductive events. This study analyzed the AZA studbook records for all litters born in captivity from 2008 to 2014 (N = 47) to assess whether any correlations existed between historical data and timing of parturition events. ANOVA tests found significant differences in mean parturition date between litters by dam origin region (F = 6.09, p-value = 0.018) and by parturition location (F = 12.73, p-value = 0.001). A Mann-Whitney u test found a difference (p-value = 0.0365) between median parturition dates of litters born in the north and those born in the south regions. PCA testing showed that the data form independent groups by both dam and sire origin latitudes, confirming the existence of a significant relationship between latitude and the timing of reproductive events. However, this study did not conclusively determine which latitude (the origin of the dam, origin of the sire, or latitude at the time of breeding) has the most influence on reproductive events among the captive North American river otter population. Future work should strive to identify other variables related to physiological condition and/or genetic variation between North American river otter subspecies. These factors may lead to more discreet groups and will likely aid in the development of a predictive model of parturition timing among the captive population using known life history data

Developmental immunity of the skeletal elements of the Weberian apparatus to the effects of exogenous estrogen (17-β estradiol), a known disruptor of cartliage development

Proper vertebrate development is controlled by a tightly regulated sequence of gene activation and repression. Exposure to both endogenous (hormones, gene products) and exogenous (environmental chemicals, toxins, etc.) substances during development can have profound effects on morphology by altering growth, cell fate, cell differentiation, and cell migration. Waterways have long been hot-spots for chemical and toxin accumulation, due to runoff and waste dumping. Growing concern is being paid to endocrine disruptors, like estrogen (17β-estradiol), which are found in increasing levels in rivers and streams. Endocrine disruptors are known to cause a varied number of defects in fish species, but the effect of estrogen on early vertebral development is unknown. In this study, the effect of exogenous estrogen (17β-estradiol) on development of the zebrafish Weberian apparatus is examined. The Weberian apparatus is an evolutionary adaptation of the four anteriormost vertebrae, and is unique to otophysan fishes (minnows, catfishes, characins, and South American electric eels). The function of the Weberian apparatus is to relay and amplify sound pressure changes from the gas bladder to the inner ear through physical coupling, and is hypothesized to be an independent developmental and evolutionary module, separate from ancestral vertebrae. High-dose estrogen proved lethal to larval zebrafish. Lower concentrations and shortened exposure times produced no morphological abnormalities within the cartilage elements of the Weberian apparatus, and overall effect on cranial cartilages was inconclusive. In addition, growth rates were not different across treatment groups. Results suggest that the Weberian apparatus may be immune to low doses of estrogen during early larval development, but given the overall lack of morphological effects across the body, immunity may not be limited to the Weberian apparatus alone

NASA Langley's AirSTAR Testbed: A Subscale Flight Test Capability for Flight Dynamics and Control System Experiments

As part of the Airborne Subscale Transport Aircraft Research (AirSTAR) project, NASA Langley Research Center (LaRC) has developed a subscaled flying testbed in order to conduct research experiments in support of the goals of NASA s Aviation Safety Program. This research capability consists of three distinct components. The first of these is the research aircraft, of which there are several in the AirSTAR stable. These aircraft range from a dynamically-scaled, twin turbine vehicle to a propeller driven, off-the-shelf airframe. Each of these airframes carves out its own niche in the research test program. All of the airplanes have sophisticated on-board data acquisition and actuation systems, recording, telemetering, processing, and/or receiving data from research control systems. The second piece of the testbed is the ground facilities, which encompass the hardware and software infrastructure necessary to provide comprehensive support services for conducting flight research using the subscale aircraft, including: subsystem development, integrated testing, remote piloting of the subscale aircraft, telemetry processing, experimental flight control law implementation and evaluation, flight simulation, data recording/archiving, and communications. The ground facilities are comprised of two major components: (1) The Base Research Station (BRS), a LaRC laboratory facility for system development, testing and data analysis, and (2) The Mobile Operations Station (MOS), a self-contained, motorized vehicle serving as a mobile research command/operations center, functionally equivalent to the BRS, capable of deployment to remote sites for supporting flight tests. The third piece of the testbed is the test facility itself. Research flights carried out by the AirSTAR team are conducted at NASA Wallops Flight Facility (WFF) on the Eastern Shore of Virginia. The UAV Island runway is a 50 x 1500 paved runway that lies within restricted airspace at Wallops Flight Facility. The facility provides all the necessary infrastructure to conduct the research flights in a safe and efficient manner. This paper gives a comprehensive overview of the development of the AirSTAR testbed

Jimmy Bedgood

SSgt. Jimmy Bedgood, May 20, 1946 - May 6, 1968 Native Sons Exhibit Pagehttps://kb.gcsu.edu/nativesons/1012/thumbnail.jp

The Untold Voyage of Saint Cormac: A Study of Voyage Literature throughout History in Conjunction with the Practice of Peregrinatio in 6th Century Ireland

Through the narrative of this creative thesis, I will explore the sixth century monastic practice of peregrinatio and the nautical motifs found throughout the literary canon of voyage literature. The power of narrative, as seen in this thesis, immerses the reader into a story, allowing them to delve into the consciousness of characters to better understand the themes behind their inner-conflict. A character’s actions and thoughts become clear to the reader through narration, inspiring a deeper identification and perceived-empathy with the characters that a history of the event could not achieve. This chronicle juxtaposes the ideas of sanctity and insanity, a subjective distinction, as the Irish monk, St. Cormac, experiences trials that test his faith in the midst of a desperate journey that plants doubt into the minds of both the ship’s captain and the reader. The line of St. Cormac’s actions being saintly or insane becomes muddled the further into the unforeseen pilgrimage the crew and the reader gets. I propose to create a fictional account of St. Cormac’s undocumented journey into the far, perilous, and trying northern sea, collecting themes from voyage literature and monastic practices to develop a story that questions the faith of the character as well as the reader