264 research outputs found
Polar substituent effects in the bicyclo[1.1.1]pentane ring system: acidities of 3-substituted-bicyclo[1.1.1]pentane-1-carboxylic acids
No full textExperimental gas-phase acidities are reported for a series of 3-substituted (X) bicyclo [1.1.1]pent-1-yl carboxylic acids (1, Y = COOH). A comparison with available calculated data (MP2/6-311++G**//B3LYP/6-311+G**) reveals good agreement. The relative substituent effects are shown to be adequately described by a much lower level of theory (B3LYP/6-31+G*). Various correlations are presented which clearly point to polar field effects as being the origin of the relative acidities
Origin of diastereofacial selectivity in tertiary 2-adamantyl cations
No full textThe intrinsic factors governing the diastereofacial selectivity of 2-methyl-5-X-2-adamantyl cations (X = F (I-F), Si(CH3)(3) (I-Si)) toward a representative nucleophile, i.e., methanol, have been investigated in the gas phase at 750 Torr and in the 20-80 degreesC temperature range. The kinetic results indicate that CH3OH addition to I-F proceeds through tight transition structures (TSFsyn and TSFanti) characterized by advanced C-O bonding. The same interactions are much less pronounced in the comparatively loose transition structures involved in the CH3OH addition to I-Si (TSSisyn and TSSianti). The experimental evidence indicates that the activation barriers for the anti addition to I-F and I-Si are invariably lower than those for the syn attack. Large adverse entropic factors account for the preferred syn diastereoselectivity observed in the reaction with I-F. Entropy plays a minor role in the much looser transition structures involved in the reaction with I-Si, which instead exhibits a preferred anti diastereoselectivity. Comparison of the above gas-phase results with related theoretical and solution data suggests that the diastereofacial selectivity of I-F and I-Si measured in solution arises in part from the differential solvation of the two faces of the pyramidalized ions
Shea, Neil. Interview about the Fowler House in Brigus.
No full textMegan Webb interviews Neil Shea about his familial relation to a past owner of the Fowler House in Brigus, his time spent there in the summers, and the layout of the house prior to rennovations.0:00 Start of recording; 0:27 Hello; 1:20 Introductions; 1:42 Connection to Fowler House; 3:45 Sadie (nee Shea) Fowler; 5:35 Thinking Richard’s parents owned the house before Rich & Sadie took over, his mother lived with them for a period of time; 6:15 Rich had a sister maybe named Madeline; 6:55 Layout of house in 1950s and 60s; 8:01 No indoor plumbing, just an outhouse up the hill and a washbasin; 8:30 Spare room in back on 2nd floor entrance to twine loft or up ladder from store; 9:09 A lot of acreage - grew potatoes, turnips, cabbages; 9:28 Next to kitchen had a coal shed, just down from that was a chicken coop; 9:45 Rich owned a small wharf, large fishing shed, and boat in key down from bridge; 10:55 Two stoves on 1st floor; 11:30 Explanation of layout of 1st floor; 12:40 Second floor layout; 14:56 Sadie approached from Brigus Historical Society about preserving house when Rich went into a home; 21:12 Remembering the pantry, kitchen, and the stairs from 1st to 2nd floor; 21:50 Location of the pantry; 22:00 Kept “perishables” on rock wall in the pantry as it was colder; 22:26 Hand pump in basin in kitchen feeding off natural well; 22:38 Trout in the well; 23:22 Chicken coop for fresh eggs; 23:50 Kitchen had a wood stove, in the 80s got an oil stove; 24:17 Coal shed to feed the stoves; 25:32 Location of wood stoves; 36:23 Memory of his sister’s casket & wake held at Fowler house 1965; 51:20 Thanks; 51:49 End of recording
Aspects of the interrenal function, stress response, sexual dimorphism and growth performance of the Atlantic halibut, Hippoglossus hippoglossus
No full textGrowth rates between individually tagged Atlantic halibut, from a single batch of farm produced eggs, on-grown in sea cages and pump ashore tanks for three years were significantly different. The tank reared fish 405g - 5992g showed a 29% premium in growth (final weight) compared to the cage reared fish 444g -4640g. Females in both systems reached a greater size (7352g tanks, 5836g cages) than males. Males that matured early (3819g tanks, 2877g cages) had a lower mean end weight than males maturing a year later (4326g tanks, 3086g cages). Early maturing males had the largest initial size. Seasonal variations in growth were observed for all groups. Major divergences in growth between males and females only became apparent when the males first matured at around 1.5 - 2 kg. No female maturation was observed during the trial. Halibut growth was determined to be positively allometric with growth of males being more linear then females. Condition factor increased with time whilst there was a decrease in Specific Growth Rate (SGR) from approximately 0.5%day⁻¹ to 0.1%day⁻¹ throughout the trial. Concentrations of plasma cortisol, osmolality, chloride and glucose measured through the trial provided no evidence of chronic stress at either site. Acute confinement stress (2, 12 and 30 minutes) was shown to elicit both primary and secondary stress responses in accordance with other marine teleosts. Increases in plasma cortisol, osmolality, CI⁻, Na⁺ and glucose were observed, reaching maximum concentrations within 80 minutes, although there was no effect on plasma K⁺. The duration of the confinement appeared to have no effect on the magnitude of the response. Following repeat confinements (4 days later) there was no evidence of either habituation or a cumulative effect in terms of cortisol or glucose whereas the effects on osmoregulatory function (Na⁺, CI⁻ and osmolality) appeared to be longer lasting. The results provided the first information regarding the stress response of the Atlantic halibut and enabled a better interpretation of the vales measured in the fish reared in tanks and cages (chapter 1). In vitro cortisol production (% above basal secretion), measured by radioimmunoassay, from perifused interrenal tissue of the Atlantic halibut was significantly stimulated by porcine adrenocorticotrophic hormone (ACTH) (0.01-1.0 μM) and [Asn¹, Val⁵] angiotensin II (All) (0.1-lO μm). No significant increase in cortisol production resulted from physiological levels of potassium (K⁺) although non-physiological levels (lOmMKl) did elicit a mild response in comparison to the effects of ACTH and All. Maximum steroid production was in response to 0.01μM ACTH (1351% above basal secretion) and 1.0μM All (397% above basal secretion). With increased concentrations above these levels of both ACTH and All there was a reduction in the degree of cortisol stimulation. The results show that the interrenal tissue of the Atlantic halibut responds in accordance to that of other teleosts to classical steroidogenic peptides
Gas-phase facial diastereoselectivity of equatorial and axial 4-chloro-adamant-2-yl cations
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Rainbow trout cystatin C : gene expression, heterologous production and characterization
No full textRainbow trout cystatin C cDNA has been isolated from
trout liver. The full-length cystatin cDNA (674 bp)
included the 5'untranslated region and the polyadenylation
signal sequence AATAAA in the 3' region. Translation of
the cDNA defines 132 amino acid residues. Comparison of
the amino acid sequence with those of family 2 cystatins
indicates that the 21 amino acids at the N-terminal end is
a signal peptide necessary for cystatin secretion, and the
remaining 111 amino acids represent mature cystatin. Four
cysteine residues in the cystatin may form two disulfide
bonds producing a molecule with the properties of a family
2 cystatin.
Trout cystatin C gene expression was analyzed by
Northern blot. This gene is expressed at various levels in
all tissues examined. This difference may reflect
differences in degree of regulation of cysteine proteinase
activities. A high level of trout cystatin C expressed in
trout hepatic tissue or cell cultures suggested that
cystatin C expression might be related to tumorigenesis.
Southern blot of trout genomic DNA showed that the copy
number of the trout cystatin gene is probably one per
haploid genome.
Trout cystatin C was expressed in E. coli at a yield
of 3-5 mg/L culture, but no inhibitory activity was
detected for the untreated recombinant protein. However,
after refolding, recombinant cystatin C displayed
inhibitory activity against papain. The dissociation
constant of recombinant cystatin C against papain is 1.2 x
10⁻⁶ nM, similar to that of human cystatin C. Trout
cystatin C was also expressed in yeast cells, but no
inhibitory activity was detected either. No cystatin C was
secreted in the yeast expression system using either the
trout cystatin C secretion signal, or the yeast invertase
secretion signal. The expression levels of trout cystatin
C in our expression systems are still low for industrial
requirements. Therefore, further investigation will be
needed to construct more efficient expression systems and
vectors for trout cystatin C heterologous production
Leveraging omics for bull trout conservation
No full textDeclines in bull trout (Salvelinus confluentus) populations across North America have prompted increased collaboration among academic, governmental, private, non-profit, and Indigenous groups to improve conservation strategies. Bull trout experience multiple stressors including habitat fragmentation, interspecific competition, fishing mortality, and climate change-induced warming. These threats to bull trout populations highlight the need to utilize approaches to rapidly assess the health and status of wild populations. This review synthesizes recent advances in omic tools applied to bull trout conservation with an emphasis on transcriptional profiling, genomics, and environmental DNA. Given their protected status, which limits lethal sampling in the wild, non-lethal and minimally invasive sample collection is required. Integrating omics with existing frameworks such as species distribution modelling has the potential to modernize conservation practices and guide recovery strategies for this at-risk species. Addressing limitations of current omic approaches for bull trout, including the absence of a sequenced genome, will be important to further advance tools for their management.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Metabolic performance and thermal preference of Westslope Cutthroat Trout Oncorhynchus clarkii lewisi and non-native trout across an ecologically relevant range of temperatures
No full textThe physiology and behaviour of fish are strongly affected by ambient water temperature. Physiological traits related to metabolism, such as aerobic scope (AS), can be measured across temperature gradients and the resulting performance curve reflects the thermal niche that fish can occupy. We measured AS of Westslope Cutthroat Trout (Oncorhynchus clarkii lewisi) at 5, 10, 15, 20, and 22C and compared temperature preference (Tpref) of the species to non-native Brook Trout, Brown Trout, and Rainbow Trout. Intermittent-flow respirometry experiments demonstrated that metabolic performance of Westslope Cutthroat Trout was optimal at ~15 C and decreased substantially beyond this temperature, until lethal temperatures at ~25 C. Adjusted preferred temperatures across species (Tpref) were comparatively high, ranging from 17.8-19.9 C, with the highest Tpref observed for Westslope Cutthroat Trout. Results suggest that although Westslope Cutthroat Trout is considered a cold-water species, they do not prefer or perform as well in cold water (≤ 10C), thus, can occupy a warmer thermal niche than previously thought. The metabolic performance curve (AS) can be used to develop species‐specific thermal criteria to delineate important thermal habitats and guide conservation and recovery actions for Westslope Cutthroat Trout.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Bull Trout, Salvelinus confluentus, and North American Porcupine, Erethizon dorsatum, Interaction in the Mackenzie Mountains, Northwest Territories
No full textEvidence of an interaction between a Bull Trout (Salvelinus confluentus) and a North American Porcupine (Erethizon dorsatum), was observed during a fisheries survey in the Mackenzie Mountains, Northwest Territories. A male Bull Trout with porcupine quills imbedded in its mouth was collected. It is speculated that this occurred when the trout was aggressively defending its territory from a perceived threat – a swimming porcupine. This is the first documented account of an interaction between a fish and a porcupine
Comparative susceptibilities of salmonids to Lepeophtheirus salmonis infections: Biochemical and physiological studies
No full textThe objective of the present study was to investigate possible mechanisms behind the differential susceptibility of coho salmon ( Oncorhynchus kisutch), rainbow trout (O. mykiss) and Atlantic salmon (Salmo salar) to sea lice (Lepeophtheirus salmonis) infection. Baseline levels of a number of innate immune factors in fish mucus and plasma were examined to establish a foundation from which to examine immunological, biochemical and physiological changes associated with lice infection. Finally, the response of lice to mucus of different species was examined.For the sea lice challenge experiment, rainbow trout, coho and Atlantic salmon were cohabited to ensure equal sea lice infection levels. To determine the response of lice to the mucus of different species, live lice were incubated in the presence of fish skin mucus or seawater. (Abstract shortened by UMI.).Source: Masters Abstracts International, Volume: 40-03, page: 0634.Advisers: John F. Bunka; Neil W. Ross
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