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Screening fatty acid profiles of fungal and oomycete strains, and optimizing growth conditions of pythium oopapillum for EPA and ARA production
No full textEicosapentaenoic acid (EPA) and arachidonic acid (ARA) are polyunsaturated fatty acids with important health impacts, commonly obtained from fish oil and other animal products. Oils of marine organisms occupying lower trophic levels are promising alternative sources of EPA, as they can be rich in omega-3 fatty acids and have the potential to be cultivated efficiently and sustainably.
While some oomycetes are reported to produce EPA and ARA, many species such as Pythium oopapillum have not been investigated for their fatty acid production. There is also a lack of research on lipid production by marine fungi. In this study, the fatty acid profiles of ten Pythium and Phytophthora oomycete strains collected in Nova Scotia and Italy were screened, along with those of 104 marine fungal and oomycete strains collected in Japan, Italy, and Costa Rica. Strains were grown for 7 days at 20-25°C, 200 rpm before biomass was harvested and fatty acid methyl esters (FAMEs) analysis was conducted using gas-liquid chromatography. Of the 104 novel marine fungal and oomycete strains screened, only one oomycete (Phytophthora inundata) produced EPA, while some strains produced ARA in small quantities. P. oopapillum proved the most promising oomycete strain, and growth conditions were optimized to increase its EPA yield. A Plackett-Burman design was used to test the effects of ten media ingredients. Yeast extract had a significantly positive effect on the strain's EPA yield, while a high initial glucose level had a negative effect. Temperature had the largest impact on EPA yield; P. oopapillum produced the highest yield (134.63mg/L) grown for 4 days at 25°C followed by 3 days at 15°C. This temperature shift likely balanced biomass growth rate and unsaturated fatty acid production. Removal of MgSO4 • 7H2O increased P. oopapillum's EPA yield from 92 to 106 mg/L when grown at 25°C for 7 days, due to an increase in total fatty acid content. Further optimization of growth conditions is needed to determine whether this oomycete is suitable for commercial fatty acid production; factors such as pH, dissolved oxygen, and media supplementation with other ingredients should be investigated
Population dynamics of root-feeding Grape Phylloxera (Daktulosphaira vitifoliae) emergence in relation to gall presence, temperature, and vine phenology
No full textGrape phylloxera, Daktulosphaira vitifoliae, are one of the most economically important insect pests of commercial grapevines. Since discovery of their damage to grapes in the 1860s, many methods to manage this species have been attempted. The most successful management method for D. vitifoliae has been the use of resistant rootstocks. Unfortunately, as new, more virulent D. vitifoliae biotypes emerge, these rootstocks are becoming more susceptible. Chemical management options for D. vitifoliae are limited and are most effective when applied to D. vitifoliae at the crawler stage. The objectives of this study were to (1) determine the seasonal dynamics of soil emerging D. vitifoliae populations; (2) relate soil emerging D. vitifoliae population dynamics to leaf gall
presence; and (3) relate air and soil temperatures and vine phenology to observed D. vitifoliae populations. The overall goal of these objectives was to determine the most effective time for application of management practices. Traps placed within a block of Marquette grapes were used to collect emerging D. vitifoliae over the 2020 growing season and determine their seasonal population dynamics. These populations were correlated with gall presence, temperature, and vine phenology. Daktulosphaira vitifoliae was determined to have a bimodal seasonal distribution that was significantly correlated with temperature and vine phenology. Gall presence was not significantly related to D. vitifoliae emergence but did reveal that D. vitifoliae populations move throughout the vineyard primarily due to prevailing wind patterns. The most effective time to manage crawlers was determined to be when grapevine phenology stages are around rapid shoot and inflorescence development, and berry development, in combination with soil temperatures ranging from 21-25°C
Local ecological knowledge predicting fish behaviour: a diverse and holistic approach to fish ecology
No full textCurrent fisheries management is dominated by Western science. However, the incorporation of other knowledge systems is gaining inertia, used to diversify decision-making processes and offer
additional information about species ecology. Through discussions with Mi'kmaq and Fisher members of the Apoqnmatulti'k project, a list of Local Ecological Knowledge links between fish behaviour and biological and physical variables was created. Two case studies were chosen and explored by using Western-Scientific data to strengthen our understanding of a cue provided by Local Ecological Knowledge holders. The first case study related the abundance of Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) in the Saint John River, New Brunswick, to the first harvest of hay. It was determined that the first harvest occurs in late May or early June. After the annual June mandated closure of the sturgeon fishery, the number caught increased. The highest numbers of aturgeon were generally seen in early July, and the number of females caught at this time dominated the number of males. This can be used as a low-cost predictor of behaviour and can indicate when you are likely to interact with the species. The second case study related the rainbow smelt (Osmerus mordax) run in the Gaspereau River, Nova Scotia, to moon phases. As the best fishing for smelt during their run was predicted to occur at the full or new moon. The Rayleigh's Test of uniformity indicated a uniform distribution of start dates in the lunar cycle, showing no correlation. A
Chi-squared test indicated no statistically significant difference between lunar phases. An additional analysis was completed, investigating a possible correlation between degree days of one and two weeks prior to the smelt run with the start date. This analysis demonstrated no relationship for either interval. These results could be for several reasons, including air temperatures being used as a proxy for water temperature increases variability, the short scale of the degree days used in the analysis, or lack of variability in the run date. These case studies wove a variety of knowledge types, rather than relying on one alone, and this model demonstrates potential for further investigation. Alternative knowledge systems were crucial in these analyses and the completion of this study
Enhancing excited state intramolecular proton transfer reaction efficiency with ortho-alkyl substituents
No full textPhenols experience an increase in acidity when excited to their singlet excited state. When this occurs, they may undergo an excited state intramolecular proton transfer (ESIPT) reaction, where the acidic proton on the hydroxyl group will transfer to a basic site on the same molecule. This research aims to increase the quantum yield of these reactions by adding R groups of increasing size to the 6-position on 2-phenylphenol (13).
6-Ethyl-2-phenylphenol (29) and 6-iso-propyl-2-phenylphenol (30) were prepared via bromination and Suzuki coupling, giving yields of 29% and 9%, respectively. These were then studied using IR spectroscopy and product studies. 1H and 13C{1H} NMR spectroscopy were used to determine deuterium incorporation and thus determining quantum yields. Both 29 and 30 underwent ESIPT and reverse proton transfer (RPT), giving
a lower limit of F=0.40. IR data indicated that with increasing size of the added R groups, the molecule will preferentially adopt a conformation where the phenol OH is oriented toward the phenyl ring.
These results are consistent with the hypothesis that increasing size of R groups added at the 6-position will increase quantum yields of ESIPT
Quantification of three trace elements in the tissues of five species of coastal fishes from the Bay of Fundy, Nova Scotia
No full textAlthough fish provide great health benefits for consumers, they are also repositories for contaminants. Current Nova Scotian consumption guidelines for fish are limited to six freshwater species and are based on mercury content only, disregarding coastal fishes and other potentially harmful elements. In this study, total mercury, arsenic, and selenium were analyzed in the tissues of five species of marine fishes: Striped bass
Morone saxatilis, American eel Anguilla rostrata, Alewife Alosa pseudogarengus, American shad Alosa sapidissima, and Atlantic tomcod Microgadus tomcod. Samples of muscle, liver, and gonad tissue were cryogenically ground and freeze-dried prior to elemental analysis by TDA-AAS and ICP-MS. Nearly all species and tissues had concentrations exceeding Health Canada's maximum level of 0.5 mg∙kg-1 for mercury and 3.5 mg ∙ kg-1 for arsenic in fish. All sample selenium concentrations were consistently below the EPA's toxic threshold of 11.3 mg ∙ kg-1 for freshwater fishes. Atlantic tomcod were particularly high in arsenic and selenium compared to other species. Significant relationships between total mercury concentrations in fish tissues, total length, and across trophic levels indicated mercury bioaccumulation and biomagnification was occurring. Total arsenic concentrations as a function of length increased in Alewife and decreased in Striped bass. Tissue contaminant distribution varied according to element and fish species; however, small sample sizes prevented some analyses. Concentrations of mercury and arsenic were higher than reported in previous studies. This study highlights the need for restricted fish consumption, a regional database, and a continued monitoring program to assess fish health, and for creating consumption guidelines and advisories where they are currently lacking
Behavioural and electroencephalographic effects of prism adaptation in young adults and children
No full textBackground. Spatial neglect is a common attentional disorder that can occur after stroke across the lifespan. Prism adaptation (PA) is a promising treatment for neglect but some studies on its effectiveness have yielded mixed results. The present studies investigated PA effects induced by a new procedure (Peg-the-Mole or PTM) in a group of young adults and in a preliminary group of children. A possible neural correlate (i.e., P300 wave) for the development of PA after-effects was examined. Methods. Forty-two healthy young adults used PTM with 5-degree or 15-degree rightward shifting goggles (Study 1). Fourteen children used PTM with 15-degree rightward shifting goggles (Study 2). All participants alternated between wearing prism and sham goggles to allow for repeated adaptation. Proprioceptive and visual pointing straight ahead tasks were administered before and after PTM to measure after-effects. Parietal P300 amplitudes elicited following the sound initiating pointing movements were examined in each condition. Results. The use of PTM with 15-degree goggles induced significant after-effects on both the proprioceptive and visual outcome tasks in young adults and children (p < 0.05). In young adults, the magnitude of after-effects was larger in the 15-degree than in the 5-degree condition (p < 0.05). Overall, a P300 response was generated in young adults and children, with larger amplitudes for prism than sham blocks (p < 0.05). In young adults, trends for the 15-degree goggles inducing larger P300 amplitudes than the 5-degree goggles were noted at electrodes P7 and P8. Implications. Aftereffects were observed in both studies, suggesting that PTM may be a PA treatment that could be used across the lifespan. In young adults, the study confirmed that this protocol can be used to study the development of after-effects of different magnitudes. A P300 wave was observed during the use of PTM in both young adults and children, suggesting that it could reflect a neural correlate underlying the development of PA after-effects.</p
Cervical muscle strength and kinematics during an unanticipated perturbation in university aged male and female rugby athletes
No full textConcussions are an inevitable risk posed to all athletes, especially those within contact sports. A concussion is the result of linear and angular kinematics of the brain tissue caused by direct and indirect head contact. Female athletes participating in contact sports demonstrate a concussion injury risk factor that is two times greater than their skill and age-matched male counterparts. Rugby is one of such contact sports
in which tackles comprise the main mechanism for concussion; which is caused by inertial impacts, rather than direct impact to the head. In numerous sports, female athletes exhibit higher measurements of acceleration and therefore higher concussion risk. Recent literature has outlined the importance of neck muscle strength and neuromuscular characteristics in the mitigation of excessive head kinematics resulting in
such brain injuries. In theory, those who display greater strength and anticipatory activation of the cervical musculature will decrease the amount of head acceleration experienced, and lower concussion risk substantially. The current study investigated the effect of sex on musculoskeletal and neuromuscular characteristics of the cervical musculature, as well as head kinematics during a simulated landing-portion of a rugby tackle. Twenty-three (females n = 15, males n=8) university-aged rugby athletes participated in an unanticipated perturbation simulation; and a series of clinical tests of the cervical musculature. Anthropometrics of the head and neck, including neck girth, head girth, head-neck segment length and mass,were ob tained. Maximal isometric neck strength was measured in kilograms of force (kgf) in all planes of motion, using handheld dynamometry. Endurance of the neck musculature was determined using the Isometric Endurance test. Electromyography and accelerometers were used to analyze activity of the sternocleid omastoid, upper trapezius, external and internal oblique muscles; as well as to quantify head, neck, and trunk change in velocity during a simulated unexpected dynamic task. One-way MANOVAs were used to determine sex differences in anthropometrics, muscle activation, and head kinematics. Independent t-tests were used to compare neck muscle endurance. The results of this study found that males demonstrated significantly greater neck girth, head girth, and head-neck segment mass. Isometric strength was significantly different with exception of the left upper trapezius; with males demonstrating 40-60% greater strength. Males demonstrated 43% greater muscle endurance than females. No statistical significance in neuromuscular activation was found between
sexes; however, female participants exhibited a muscle activation strategy of bilateral co-contraction of the sternocleidomastoid, while males utilized contralateral muscles to the diving direction in order to stabilize the head. Males had statistically significant greater change in velocity of the head in the sagittal plane. In agreement with current literature, males and females demonstrate differences in their ability to stabilize the head in dynamic situations. This data suggests even female competitive rugby players demonstrate significant clinical factors that increase risk of concussion. Determining where differences exist in injury risk between males and female rugby athletes can help to design specific injury prevention interventions
Plasticity of pheromone chemistry and female olfactory sensitivity in the tobacco budworm moth Heliothis virescens
No full textAutodetection is a term used in insect pheromone communication to describes the ability of females to detect their own conspecific sex pheromone blend. The importance of autodetection to calling, spacing and other mating-related behaviour in the family Heliothinae is a recently emerging field of study, and as such the molecular mechanisms involved in the regulation of heliothine autodetection remain poorly understood. The objectives of this study were to examine the response of antennal olfactory receptors (ORs) following to pheromone exposure in female moths, and to examine if changes in antenna OR expression were related to
changes in pheromone gland OR expression or pheromone composition. Individual female Heliothis virescens moths were isolated and subjected to 18-hour exposure to either the minor component of their pheromone
blend, (Z)9-14:Ald, or to a hexane control. The pheromone blends of moths exposed to (Z)9-14: Ald had a slightly decreased ratio of (Z)11-16: Ald to (Z)9-14: Ald, from 5.31 to 3.83, as measured by relative amounts of
both compounds measured by chromatography. The expression of OR6 was found to have increased in the antenna tissue samples, and decreased in the pheromone gland tissue samples. The results suggest that in female heliothine moths, pheromone exposure may influence OR expression on the antenna as well as in other tissues, which may subsequently influence pheromone production and related behavioral outcomes in mating
What does it mean for youth to live in a climate emergency?: perspectives and experiences of living and searching for meaning in existential times
No full textThe narrative of a climate emergency has increased exponentially as a term to describe the state of climate change, its repercussions, and the need for action. Thousands of political jurisdictions worldwide have declared a state of climate emergency. Young people have taken to the streets, fighting no longer just for their futures but for their current lives, and for all life on Earth. Inspired by this tumultuous context, this research seeks to explore the concept and condition of a climate emergency, moving beyond scientific and political usages and understandings, to gain more insights into other dimensions of a climate emergency as, interconnectedly, an affective discursive term, a lived reality, and a conceptual challenge. This research asks: What does it mean for youth to live in a climate emergency? Youth voices are often overlooked, yet youth are now the "future generations" environmentalism had been trying to preserve. This research shares findings and stories from a group of youth on their perspectives, experiences, and emotions as they negotiate their realities and seek meaning in an emergency. This research seeks to broaden understandings of life in a climate emergency, creating an inclusive narrative that validates youth's experiences and emotions, and providing an impetus for action. Sharing circles were conducted with 12 youth, in Wolfville, Nova Scotia, to hear their stories. For these youth, living in a climate emergency means experiencing intense emotional and psychological states (anger and frustration, anxiety and fear, depressive states, guilt, helplessness, hope and gratitude, overwhelm, and sorrow and grief), having these emotions dismissed, having their everyday lives profoundly affected, and having their futures shaped and stolen. This research also prompts reflection on new conceptualizations and narratives of life in a climate emergency. Overall, this emergent research imbues the climate emergency discourse with more meanings, and has normative implications for social and political change.</p
The copycat identity in a neocolonial Bahamas
No full textWhen the 2015 Junkanoo Carnival festival made its debut in the Bahamas, it seemed as if the native Bahamian cultural festival Junkanoo had been perverted into a culture that was unrelated to the Bahamia n identity.
The decision to diversify the tourism product in this way led to a marginalization of native Bahamian culture. The tourism industry's decision provoked an inquiry into the Bahamian identity. On the surface, Bahamian identity appears to be copied from other cultures. Copying other cultures results from the neocolonial ultimatum to participate in globalization while suffering a marginalized identity over risking not surviving in a world of
global capitalism. Therefore, the Copycat identity is formed through neocolonial processes. The Bahamian tourism industry facilitates neocolonialism and the Copycat identity by producing neocolonial relationships and manipulating Bahamian culture to reflect the values of the neocolonizer –the tourist. After unveiling the neocolonial effects on Bahamian culture and identity, it is seen that the Copycat identity is merely a Junkanoo identity in which the Bahamian adapts to and acquires the music, dance, and artistry. Like the festival, the Junkanoo identity reflects the authentic identity of the Bahamian as opposed to the neocolonial identity. The Calypsonian Cyborg makes it possible to shift from the Copycat identity to the Junkanoo identity through the process of decolonization. Challenging and questioning the Bahamian situation also make it possible to decolonize and achieve a true Bahamian identity