Dietary effects on protein turnover in three pinniped species, Eumetopias jubatus, Phoca vitulina, and Leptonychotes weddellii

Thesis (Ph.D.) University of Alaska Fairbanks, 2019The role of dietary protein in pinniped (seal and sea lion) nutrition is poorly understood. Although these marine mammals derive the majority of their daily energetic needs from lipid, lipids cannot supply essential amino acids which have to come from protein fractions of the diet. Protein regulation is vital for cellular maintenance, molt, fasting metabolism, exercise and development. Proteins are composed of linked amino acids (AA), and net protein turnover is the balance between protein synthesis from component AA, and degradation back to AA. Protein regulation is influenced by dietary intake and quality, as well as physiological and metabolic requirements. In this work, pinniped diet quality was assessed through comparisons of amino acid profiles between maternal milk, blood serum, and seasonal prey of wild juvenile Steller sea lions (Eumetopias jubatus) in Southcentral Alaska. Both Pacific herring (Clupei pallasi) and walleye pollock (Gadus chalcogramma) showed similar patterns to milk in essential and branched chain amino acid content. Serum amino acid profiles suggest the juvenile sea lions were not in protein deficit at the time of capture. Protein metabolism in the blood and urine was assessed through turnover studies using amino acid tracers. The turnover kinetics of ¹⁵N-labelled glycine in the blood amino acid and protein pool, red blood cells, and urine urea were measured in wild adult female Weddell seals (Leptonychotes weddellii) in the Antarctic. Labelled glycine moved quickly into serum protein and red blood cells (1-2 hours) and urinary urea (2-4 hours). The turnover rates in the blood amino acid and urine urea pools demonstrated a reduced turnover rate associated with molting. Lastly, whole body protein turnover experiments using a single bolus ¹⁵N-labelled glycine tracer method with endproduct collection of blood, feces and urine were conducted on 2 Cohort groups of captive Alaskan harbor seals over 2 years. Season was found to have the greatest effect on whole body protein turnover, which increased during the winter and decreased in the summer molt. Conversely, protein intake decreased during the winter and increased in the summer molt. This pattern corresponded with an increase in mass and protein synthesis in the winter, while mass decreased and protein degradation rates increased in molting seals. Weaning also influenced the patterns with reduced protein turnover in newly weaned animals that had recently transitioned from milk to a fish diet. This project presents results on whole body protein turnover rates in nonfasting pinnipeds and reveals that protein turnover is strongly regulated by developmental and seasonal physiological and metabolic demands.Alaska Sea Grant, the Alaska SeaLife Center Research Program with funds from National Marine Fisheries Service, and the National Science Foundation, Office of Polar Programs Grant 01-30417Chapter 1: General Introduction -- Chapter 2: Protein Quality in the Diet of Steller Sea Lions, Eumetopias jubatus, in Southcentral Alaska -- Chapter 3: Tracking Protein Turnover in Adult Female Weddell Seals (Leptonychotes weddellii) Using ¹⁵N-labelled Glycine -- Chapter 4: Whole Body Protein Turnover in Subadult Alaskan Harbor Seals (Phoca vitulina) -- Chapter 5: General conclusions

Clustering in iron-doped magnesium oxide

The distribution of iron in single crystals of magnesium oxide has been investigated using electron paramagnetic resonance (EPR), ferrimagnetic resonance (FMR) and reflection electron diffraction (RED). The total iron content of the samples was in the range 100 - 13000 ppm by weight, the crystals being examined in the as-received state, after solution treatment, and following various aging treatments. The solution treatment involved the samples being held at 1400ºC for 24 hours in an oxygen atmosphere, and then quenched to room temperature. The samples were aged in oxygen at temperatures in the range 600 - 800ºC for various lengths of time. The EPR investigations were carried out at 9 GHz, over the temperature range from 4 - 300 K. Comparison of the integrated intensity of the EPR spectral lines with those of a standard suggested that in both the as-received and solution treated crystals very little (in some cases <0.1%) of the iron contributes to the Fe(^3+) isolated ion cubic site spectrum. Analysis of the experimental linewidths and shapes lends support to this suggestion. The experimental linewidths are in all cases broader than is expected on the basis of dipolar broadening theory, and it is suggested that this broadening is partly due to interactions with the undetected fraction of the iron. An unusual broad (1,3 kG wide) line which shows a complex structure at liquid helium temperatures was detected in two of the samples following solution treatment. Its appearance was accompanied by a complete absence of fine structure lines from the spectra in which it appeared. It is probable that the disappearance of the fine structure and the appearance of this broad line are related, but the relationship is not at present clear. Following aging treatments ferrimagnetic resonance was detected at 9 GHz, in the temperature range 4 - 500 K. This resonance arises out of the precipitation of magnesioferrite from the host lattice. In most of the samples which showed evidence of precipitation two quite different FMR lines were found - an isotropic line which appeared after short aging times, and an anisotropic line which apparently replaces the isotropic one as aging progresses. Analysis of the measured anpsotropy field of the particles precipitated at 800ºC indicated that the rate of growth of the volume of the precipitates is linear with time, after about one hour's aging. The chemical formula for these particular precipitates was determined to be Mg(_x)Fe(_3-x)O(_4-(x-1)/2')) where x = 1.29, the fraction of Mg ions on tetrahedral sites being taken to be 0.30. Analysis of the magnetic characteristics of the precipitates generally gave agreement with what published data are available. In addition the measured anisotropy field H(^sp)(_ɑ) in all samples was found to obey the empirical relationship where D = -0.045 + .004 G(^0.5) K(^-1), T is the temperature and C is a sample dependent constant. The widths of the FMR lines obtained from the high concentration samples aged at 800ºC were independent of sample, and after aging for one hour decreased monotonically with continued aging. This change in width is possibly a consequence of 'voids' of host material in the initial precipitates filling with aging. These linewidths were also remarkable in that they showed a marked decrease with increased recording temperature. Since this behaviour is quite at variance with the behaviour of bulk magnesioferrite it is probably a consequence of the superparamagnetic nature of the particles. Reflection electron diffraction studies of the etched surfaces of the crystals showed only one pattern - the standard spinel pattern - when ferrimagnetic precipitates were present, regardless of the type of FMR spectral line produced by the precipitates. This spinel had a lattice parameter almost exactly twice that of the host. Two other RED patterns were recorded from some of the samples - one possibly due to the calcium-stabilised zirconia discussed by Venables, and the other tentatively assigned to an aluminium spinel

Hidden Broad Line Seyfert 2 Galaxies in the CfA and 12micron Samples

We report the results of a spectropolarimetric survey of the CfA and 12micron samples of Seyfert 2 galaxies (S2s). Polarized (hidden) broad line regions (HBLRs) are confirmed in a number of galaxies, and several new cases (F02581-1136, MCG -3-58-7, NGC 5995, NGC 6552, NGC 7682) are reported. The 12micron S2 sample shows a significantly higher incidence of HBLR (50%) than its CfA counterpart (30%), suggesting that the latter may be incomplete in hidden AGNs. Compared to the non-HBLR S2s, the HBLR S2s display distinctly higher radio power relative to their far-infrared output and hotter dust temperature as indicated by the f25/f60 color. However, the level of obscuration is indistinguishable between the two types of S2. These results strongly support the existence of two intrinsically different populations of S2: one harboring an energetic, hidden S1 nucleus with BLR, and the other, a ``pure S2'', with weak or absent S1 nucleus and a strong, perhaps dominating starburst component. Thus, the simple purely orientation-based unification model is not applicable to all Seyfert galaxies.Comment: 5 pages with embedded figs, ApJ Letters, in pres

On the links between nature's values and language

Recent research into the plural values about nature is focusing on relational values as a concept through which to better understand the breadth and importance of situated human–nature relations. However, potential relevance of language as a mediating factor in relational values has not been sufficiently examined. To investigate the links between language and values, we explore the influence of the ancient non-Indo-European Basque language (‘Euskara’) upon people's relationships with mountain forests in the Western Pyrenees of the Basque Country. Results based on triangulation of data from Q-methodology, focus groups and a socio-demographic survey indicate that while relational values are highly rated in all principal viewpoints about local forests, there is an emergent perspective that emphasises Euskara's key role in relations with the forest via cultural identity and place attachment. We conclude that positive relational values linked to Euskara may be seen as key levers for local sustainability transitions. The fact that positive rapports with language can have a meaningful role in human–nature relations points to the need for further research into the consequential links between biological and linguistic diversity. A free Plain Language Summary can be found within the Supporting Information of this article. © 2021 The Authors. People and Nature published by John Wiley & Sons Ltd on behalf of British Ecological SocietyWe would like to thank Simon West, Maraja Riechers, Antonio Castro and Kai Chan for their comments and suggestions during the review process. We also thank Mollie Chapman, Joe Gerlach, Rachelle Gould, Christopher Raymond, Aiora Zabala and Imanol Zabaleta for their comments on earlier drafts of the paper

Socioeconomic variations in women\u27s diets : what is the role of perceptions of the local food environment

Objectives : To test the contribution of perceived environmental factors (food availability, accessibility and affordability) to mediating socioeconomic variations in women&rsquo;s fruit, vegetable and fast food consumption. Methods : A community sample of 1580 women from 45 neighbourhoods provided survey data on their socioeconomic position (SEP) (education and income); diet (fruit, vegetable and fast food consumption); and the perceived availability of, access to and cost of healthy food in their local area. Results : Once perceived environmental variables were considered, the associations between SEP and diet were weak and non-significant, suggesting that socioeconomic differences in diet were almost wholly explained by perceptions of food availability, accessibility and affordability. Conclusions : Strategies to decrease socioeconomic inequalities in diet could involve promoting inexpensive ways to increase fruit and vegetable consumption, and ensuring that people of low SEP are aware that many healthy foods are available at relatively low cost. Future research should also confirm if perceptions match objective measures of food availability, accessibility and affordability, in order to address the real and/or perceived lack of healthy options in low SEP neighbourhoods.<br /

Sex differences in dietary consumption and its association with frailty among middle-aged and older Australians: a 10-year longitudinal survey

Background Nutritional status has been considered as a key factor in preventing the development of the frailty syndrome. However, sex-specific dietary consumption transition over time and how it impacts of frailty status are unclear. Method We assessed 113,039 adults (aged 50 years and over) from the 45 and Up Study who had completed both baseline (2006–2009) and follow-up (2012–2015) surveys. Dietary consumption was assessed by a short food frequency questionnaire. Frailty was identified by the FRAIL scale. Multinomial regression models were used to examine the association between a long-term dietary consumption and frailty, stratified by sex. Results Of a total of 113,039 participants, females had a higher percentage of pre-frailty and frailty than males (pre-frailty: 35.5% for female and 30.1% for male; frailty: 4.86% for female and 3.56% for male). As age increased, males had significant decreases in overall dietary risk scores, while females had significant increases in overall dietary risk scores. Males and females with a long-term consumption of adequate fruits, high grains or had a variety of foods were related to a low risk of frailty. Females with a long-term consumption of adequate vegetables or high lean meats and poultry were related to a low risk of frailty. Females with an unhealthy diet at both surveys [Relative Risk Ratio (RRR) = 1.32, 95% CI: 1.18; 1.49], and those with unhealthy diet at either surveys (RRR = 1.28, 95% CI: 1.12; 1.47, RRR = 1.19, 95% CI: 1.04; 1.37) had a higher risk of frailty compared to those had a long-term healthy diet. No association were found between overall dietary risk and frailty for males. Conclusion Males and females changed their dietary consumption as they age. These changes affect its association with frailty, particularly for females. Sex-specific dietary advice in prevention of frailty needs to be further developed

Comparative genotypic and pathogenic examination of Campylobacter concisus isolates from diarrheic and non-diarrheic humans

<p>Abstract</p> <p>Background</p> <p><it>Campylobacter concisus </it>is an emerging enteric pathogen, yet it is commonly isolated from feces and the oral cavities of healthy individuals. This genetically complex species is comprised of several distinct genomospecies which may vary in pathogenic potential.</p> <p>Results</p> <p>We compared pathogenic and genotypic properties of <it>C. concisus </it>fecal isolates from diarrheic and healthy humans residing in the same geographic region. Analysis of amplified fragment length polymorphism (AFLP) profiles delineated two main clusters. Isolates assigned to AFLP cluster 1 belonged to genomospecies A (based on genomospecies-specific differences in the 23S rRNA gene) and were predominantly isolated from healthy individuals. This cluster also contained a reference oral strain. Isolates assigned to this cluster induced greater expression of epithelial IL-8 mRNA and more frequently contained genes coding for the zonnula occludins toxin and the S-layer RTX. Furthermore, isolates from healthy individuals induced greater apoptotic DNA fragmentation and increased metabolic activity than those from diarrheic individuals, and isolates assigned to genomospecies A (of which the majority were from healthy individuals) exhibited higher haemolytic activity compared to genomospecies B isolates. In contrast, AFLP cluster 2 was predominated by isolates belonging to genomospecies B and those from diarrheic individuals. Isolates from this cluster displayed greater mean epithelial invasion and translocation than cluster 1 isolates.</p> <p>Conclusion</p> <p>Two main genetically distinct clusters (i.e., genomospecies) were identified among <it>C. concisus </it>fecal isolates from healthy and diarrheic individuals. Strains within these clusters differed with respect to clinical presentation and pathogenic properties, supporting the hypothesis that pathogenic potential varies between genomospecies. ALFP cluster 2 isolates were predominantly from diarrheic patients, and exhibited higher levels of epithelial invasion and translocation, consistent with known roles for these factors in diarrhoeal disease. Conversely, isolates from healthy humans and AFLP cluster 1 or genomospecies A (which were predominantly isolated from healthy humans) exhibited increased haemolytic ability, apoptotic DNA fragmentation, IL-8 induction, and/or carriage of toxin genes. Given that this cluster contains an oral reference strain, it is possible that some of the AFLP cluster 1 isolates are periodontal pathogens and may cause disease, albeit via a different mechanism than those from AFLP cluster 2.</p

Automated identification of neurons and their locations

Individual locations of many neuronal cell bodies (>10^4) are needed to enable statistically significant measurements of spatial organization within the brain such as nearest-neighbor and microcolumnarity measurements. In this paper, we introduce an Automated Neuron Recognition Algorithm (ANRA) which obtains the (x,y) location of individual neurons within digitized images of Nissl-stained, 30 micron thick, frozen sections of the cerebral cortex of the Rhesus monkey. Identification of neurons within such Nissl-stained sections is inherently difficult due to the variability in neuron staining, the overlap of neurons, the presence of partial or damaged neurons at tissue surfaces, and the presence of non-neuron objects, such as glial cells, blood vessels, and random artifacts. To overcome these challenges and identify neurons, ANRA applies a combination of image segmentation and machine learning. The steps involve active contour segmentation to find outlines of potential neuron cell bodies followed by artificial neural network training using the segmentation properties (size, optical density, gyration, etc.) to distinguish between neuron and non-neuron segmentations. ANRA positively identifies 86[5]% neurons with 15[8]% error (mean[st.dev.]) on a wide range of Nissl-stained images, whereas semi-automatic methods obtain 80[7]%/17[12]%. A further advantage of ANRA is that it affords an unlimited increase in speed from semi-automatic methods, and is computationally efficient, with the ability to recognize ~100 neurons per minute using a standard personal computer. ANRA is amenable to analysis of huge photo-montages of Nissl-stained tissue, thereby opening the door to fast, efficient and quantitative analysis of vast stores of archival material that exist in laboratories and research collections around the world.Comment: 38 pages. Formatted for two-sided printing. Supplemental material and software available at http://physics.bu.edu/~ainglis/ANRA