Development of a pathogenicity testing system for Dothistroma pini infection of Pinus radiata : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Microbiology at Massey University

Dothistroma pini is a fungal pathogen of pine species around the world and can be found in most parts of New Zealand. Infection by D. pini causes a disease commonly known as Dothistroma needle blight. Dothistroma needle blight has a significant financial impact on New Zealand's forestry industry. Although control of infection by D. pini is currently very successful there is a possibility that a new strain introduced from another country could be a lot more damaging and overcome current control measures. In recent years both the incidence and severity of the disease have increased in the northern hemisphere and other parts of the world. A distinctive characteristic of Dothistroma needle blight is the production in the infected needle of a toxic red pigment called dothistromin. Dothistromin is produced as a secondary metabolite by D. pini and has known phytotoxic properties as well as clastogenic and mutagenic properties towards human cells. Purified dothistromin toxin injected into pine needles has been shown to reproduce symptoms similar to those observed during D. pini infection. Because of this production, dothistromin is thought to play an important role in the infection process. Mutants of D. pini that are deficient in dothistromin production have been made recently that will allow this role to be investigated. The aim of this study was to develop a pathogenicity testing system under PC2 containment (required for dothistromin deficient mutant) and to develop microscopy methods required to monitor both epiphytic and endophytic growth of the fungus on the needle D. pini requires high light intensity, continuous leaf moisture and a specific temperature range in order to infect pine needles. Progress was made towards developing a robust pathogenicity testing system. This study has also developed several microscopy techniques for the visualisation of epiphytic growth including a fluorescent microscopy technique. Other bright field and fluorescent staining techniques were investigated with some success. Staining techniques were not successful for the visualisation of endophytic D. pini growth but a green fluorescent protein (sgfp) reporter construct was obtained and two gfp plasmid contracts were developed for the transformation of D. pini for use as biomarkers. Successful introduction of the gfp constructs into D. pini will allow in situ visualisation of endophytic and epiphytic D. pini growth. The work done in this study will be useful for the further investigation into the role of dothistromin toxin, which may lead to new or more efficient methods of controlling D. pini as well as possibly providing information about other polyketide molecules of economic or medical significance

The sorption of fluoride ion with special reference to fluoride removal from potable waters

The recent discovery that even very small concentrations of fluorides in drinking waters are sufficient to cause the serious dental dystrophy commonly known as mottled enamel, has around widespread interest and concern. Federal and State surveys have been conducted to determine the geographical distribution of the malady, and the fluoride contents of water supplies. County dental surveys, conducted by the United States Public Health Department with the cooperation of local dentists, have located the regions throughout the country where mottled enamel is endemic and among these localities is an area in southeastern North Dakota and adjacent territory in South Dakota and Minnesota where domestic water supplies are obtained almost exclusively from the artesian wells of the Dakota Sandstone formation. In the district the dental lesions have found to be especially severe. During the past two years the writer has assisted Professor G. A. Abbott, of the University, in making a comprehensive survey of the fluoride contents of the deeper ground waters of the State with special attention to the artesian waters of the Dakota Sandstone basin. This fluoride survey was conducted in cooperation with the State Geological Survey, first, under provisions of the Federal Emergency Relief Administration and, later, with the assistance of a WPA project which is still in progress. A field survey was made by Professor Abbott in person, beginning with the counties where mottled enamel had been reported to be most severe, and later the study was extended to include practically all of the Dakota Sandstone basin in which artesian wells are found. Dentists, physicians, school administrators, well drillers, farmers, and other citizens, were interviewed, conditions were studied and numerous representative water samples were collected and returned to the University chemical laboratory to complete analysis. With the assistance of a specially trained competent staff these waters were then analyzed, not merely for fluorides, but for complete mineral contents, following the standards of precision of the United States Geological Survey. The writer served as assistant chemist in the FERA project, and as Supervisor of the WPA project under the direction of Professor Abbott. The results obtained in the study of the artesian waters are interesting and surprising in that the distribution of fluorides was found to follow well defined areas or zones which could be mapped with regular contour lines enclosing the areas of different fluoride concentrations, ranging from about 3 parts per million of fluoride in the outermost zone, through successive concentric areas of increasing values, finally converging to a small district in the vicinity of Lidgerwood where the maximum value of 9.9 per million was found. The correlation of the analytical results with the data obtained from the dental surveys was found to be complete and convincing. In every locality where the dental lesions were pronounced, the drinking waters contained notable amounts of fluorides; while in districts where flouride-free waters are used, mottled enamel was found only among those who have moved into these districts from localities where the artesian waters are used for domestic purposes. The degree of severity of the dental lesions was found to follow the contours of the fluoride map. The recognition of these conditions has created an insistent demand for practical methods of fluoride removal, not only for use with municipal supplies, but especially for individual domestic supply in those regions where artesian water is the only available supply. Although considerable research on this problem is in progress, no entirely satisfactory method has been developed

A method of evaluating efficiency during space-suited work in a neutral buoyancy environment

The purpose was to investigate efficiency as related to the work transmission and the metabolic cost of various extravehicular activity (EVA) tasks during simulated microgravity (whole body water immersion) using three space suits. Two new prototype space station suits, AX-5 and MKIII, are pressurized at 57.2 kPa and were tested concurrently with the operationally used 29.6 kPa shuttle suit. Four male astronauts were asked to perform a fatigue trial on four upper extremity exercises during which metabolic rate and work output were measured and efficiency was calculated in each suit. The activities were selected to simulate actual EVA tasks. The test article was an underwater dynamometry system to which the astronauts were secured by foot restraints. All metabolic data was acquired, calculated, and stored using a computerized indirect calorimetry system connected to the suit ventilation/gas supply control console. During the efficiency testing, steady state metabolic rate could be evaluated as well as work transmitted to the dynamometer. Mechanical efficiency could then be calculated for each astronaut in each suit performing each movement

Developing Urban Deer Management Plans: The Need for Public Education

Independent public opinion surveys concerning urban deer (Odocoileus virginianus) management were conducted in two Virginia communities. A total of 346 citizens were interviewed in two Random Digit Dial telephone surveys. In addition to questions concerning management techniques and their administration, participants were asked about their experience with deer, their awareness of problems with deer in the area, and their enjoyment of deer. In both localities, non-lethal controls were preferred over lethal controls; trapping and relocation, fencing, repellents, and birth control measures were favored by a majority of residents. The only lethal control acceptable to residents in both communities was the use of controlled hunts. There was no consensus about who should administer deer management or who should be fiscally responsible. Those aware of deer problems are less likely to report enjoying having deer in the area. Preferences for non-lethal controls and lack of consensus on responsibility for deer management demonstrate the need for public education concerning the costs, consequences, and accountability for deer control. Survey results regarding citizens’ preferences for various management practices demonstrate the challenges wildlife professionals face in assisting communities in developing deer management plans. Wildlife professionals saddled with managing human-wildlife conflicts need to recognize that part of their role is educating the public about the ecology of the animal(s), management techniques, and their implications. As experience with deer problem increases, citizens are likely to enjoy deer less and become increasingly interested in deer management

Sorbent Structural Impacts Due to Humidity on Carbon Dioxide Removal Sorbents for Advanced Exploration Systems

The Life Support Systems Project (LSSP) under the Advanced Exploration Systems (AES) program builds upon the work performed under the AES Atmosphere Resource Recovery and Environmental Monitoring (ARREM) project focusing on the numerous technology development areas. The CO2 removal and associated air drying development efforts are focused on improving the current state-of-the-art system on the International Space Station (ISS) utilizing fixed beds of sorbent pellets by seeking more robust pelletized sorbents, evaluating structured sorbents, and examining alternate bed configurations to improve system efficiency and reliability. A component of the CO2 removal effort encompasses structural stability testing of existing and emerging sorbents. Testing will be performed on dry sorbents and sorbents that have been conditioned to three humidity levels. This paper describes the sorbent structural stability screening efforts in support of the LSS Project within the AES Program

The Closest View of a Fast Coronal Mass Ejection: How Faulty Assumptions near Perihelion Lead to Unrealistic Interpretations of PSP/WISPR Observations

We report on the closest view of a coronal mass ejection observed by the Parker Solar Probe (PSP)/Wide-field Imager for {Parker} Solar PRobe (WISPR) instrument on September 05, 2022, when PSP was traversing from a distance of 15.3~to~13.5~R$_\odot$ from the Sun. The CME leading edge and an arc-shaped {\emph{concave-up} structure near the core} was tracked in WISPR~field of view using the polar coordinate system, for the first time. Using the impact distance on Thomson surface, we measured average speeds of CME leading edge and concave-up structure as $\approx$2500~$\pm$~270\,km\,s$^{-1}$ and $\approx$400~$\pm$~70\,km\,s$^{-1}$ with a deceleration of $\approx$20~m~s$^{-2}$ for the later. {The use of the plane-of-sky approach yielded an unrealistic speed of more than three times of this estimate.} We also used single viewpoint STEREO/COR-2A images to fit the Graduated Cylindrical Shell (GCS) model to the CME while incorporating the source region location from EUI of Solar Orbiter and estimated a 3D speed of $\approx$2700\,km\,s$^{-1}$. We conclude that this CME exhibits the highest speed during the ascending phase of solar cycle 25. This places it in the category of extreme speed CMEs, which account for only 0.15\% of all CMEs listed in the CDAW CME catalog.Comment: 13 Pages, 6 Figures; Accepted in The Astrophysical Journal Letter

The Influence of Stimulus Deviance on Electrophysiologic and Behavioral Responses to Novel Events

This study investigated the role of stimulus deviance in determining electrophysiologic and behavioral responses to “novelty.” Stimulus deviance was defined in terms of differences either from the immediately preceding context or from long-term experience. Subjects participated in a visual event-related potential (ERP) experiment, in which they controlled the duration of stimulus viewing with a button press, which served as a measure of exploratory behavior. Each of the three experimental conditions included a frequent repetitive background stimulus and infrequent stimuli that deviated from the background stimulus. In one condition, both background and deviant stimuli were simple, easily recognizable geometric figures. In another condition, both background and deviant stimuli were unusual/unfamiliar figures, and in a third condition, the background stimulus was a highly unusual figure, and the deviant stimuli were simple, geometric shapes. Deviant stimuli elicited larger N2-P3 amplitudes and longer viewing durations than the repetitive background stimulus, even when the deviant stimuli were simple, familiar shapes and the background stimulus was a highly unusual figure. Compared to simple, familiar deviant stimuli, unusual deviant stimuli elicited larger N2-P3 amplitudes and longer viewing times. Within subjects, the deviant stimuli that evoked the largest N2-P3 responses also elicited the longest viewing durations. We conclude that deviance from both immediate context and long-term prior experience contribute to the response to novelty, with the combination generating the largest N2-P3 amplitude and the most sustained attention. The amplitude of the N2-P3 may reflect how much “uncertainty” is evoked by a novel visual stimulus and signal the need for further exploration and cognitive processing