Beeching, SC.(Department of Biology), Brock, BA. (former SRU undergraduate student), and Rehorek, SJ (Department of Biology) (2013) “Histology of melanic flank and opercular color pattern elements in the firemouth cichlid, Thorichthys meeki”, Journal of Morphology, DOI: 10.1002/jmor.20131, published online: 28 FEB 2013.
Dark melanic color pattern elements, such as bars, stripes, and spots, are common in the skin of fishes, and result from the differential distribution and activity of melanin-containing chromatophores (melanophores). We determined the histological basis of two melanic color pattern elements in the integument of the Firemouth Cichlid, Thorichthys meeki. Vertical bars on the flanks were formed by three layers of dermal melanophores, whereas opercular spots were formed by four layers (two lateral and two medial) in the integument surrounding the opercular bones. Pretreatment of opercular tissue with potassium and sodium salts effectively concentrated or dispersed intracellular melanosomes. Regional differences in epidermal structure, scale distribution, and connective tissues were also identified. J. Morphol. 2013. © 2013 Wiley Periodicals, Inc.
(2012) “Eye Size at Birth in Prosimian Primates: Life History Correlates and Growth Patterns”, PLoS ONE 7(5): e36097. doi:10.1371/journal.pone.0036097
Primates have large eyes relative to head size, which profoundly influence the ontogenetic emergence of facial form. However, growth of the primate eye is only understood in a narrow taxonomic perspective, with information biased toward anthropoids.
We measured eye and bony orbit size in perinatal prosimian primates (17 strepsirrhine taxa and Tarsius syrichta) to infer the extent of prenatal as compared to postnatal eye growth. In addition, multiple linear regression was used to detect relationships of relative eye and orbit diameter to life history variables. ANOVA was used to determine if eye size differed according to activity pattern. In most of the species, eye diameter at birth measures more than half of that for adults. Two exceptions include Nycticebus and Tarsius, in which more than half of eye diameter growth occurs postnatally. Ratios of neonate/adult eye and orbit diameters indicate prenatal growth of the eye is actually more rapid than that of the orbit. For example, mean neonatal transverse eye diameter is 57.5% of the adult value (excluding Nycticebus and Tarsius), compared to 50.8% for orbital diameter. If Nycticebus is excluded, relative gestation age has a significant positive correlation with relative eye diameter in strepsirrhines, explaining 59% of the variance in relative transverse eye diameter. No significant differences were found among species with different activity patterns.
The primate developmental strategy of relatively long gestations is probably tied to an extended period of neural development, and this principle appears to apply to eye growth as well. Our findings indicate that growth rates of the eye and bony orbit are disassociated, with eyes growing faster prenatally, and the growth rate of the bony orbit exceeding that of the eyes after birth. Some well-documented patterns of orbital morphology in adult primates, such as the enlarged orbits of nocturnal species, mainly emerge during postnatal development.
DeNicola, D. M. (Department of Biology), Layton, L. (former SRU student), and Czapski, T.R. (former SRU student) (2012) Epilithic community metabolism as an indicator of impact and recovery in streams affected by acid mine drainage. Environmental Management 50:1035-1046
We measured biomass and metabolism of epilithic communities on five dates in different seasons at four sites in a watershed that has received extensive restoration for acid mine drainage (AMD) through the construction of passive treatment systems. Chlorophyll a biomass and productivity directly corresponded to AMD stress from coal mining. The site downstream of extensive passive treatment had significantly greater biomass and gross primary productivity rates than the site receiving only untreated AMD, but values were below those for two reference sites, indicating incomplete recovery. The degree of difference in these metrics among sites varied seasonally, primarily related to differences in canopy cover changes,
but the ranking of sites in terms of stress generally was consistent. Reference sites had a significantly greater chlorophyll a/pheophytin ratio than untreated and treated sites, also indicating AMD stressed the communities. Community respiration was less affected by AMD stress than productivity or chlorophyll a. Productivity measures are not widely used to assess AMD impacts, and have been shown to both increase and decrease with AMD stress. The elimination of herbivores in AMD-impacted streams can increase productivity in the benthic algal community. Our study found productivity decreased with increasing AMD stress. Although sites with AMD stress had reduced herbivore populations, light, nutrients and metal precipitates appear to have limited growth of AMD-tolerant algal taxa. Therefore, it appears changes in food web structure due to AMD stress had less of an effect on epilithic productivity than environmental conditions within the stream.
Holmstrup, ME (Department of Exercise and Rehabilitative Sciences), TJ Fairchild, S Keslacy, RS Weinstock, JA Kanaley (2013) “Satiety, but not Total PYY, is Increased with Continuous and Intermittent Exercise”, Obesity. Online, 18 FEB 2013.
Objective: This study determined the hormonal and subjective appetite responses to exercise (1-h continuous v. intermittent exercise throughout the day) in obese individuals. Design and Methods: Eleven obese subjects (>30 kg/m2) underwent 3, 12-hour study days: control condition (sedentary behavior-SED), continuous exercise condition ((EX) 1-h exercise), and intermittent exercise condition ((INT) 12 hourly, 5-minute bouts). Blood samples (every 10 min) were measured for serum insulin and total peptide YY (PYY) concentrations, with ratings of appetite (visual analog scale-VAS: every 20 minutes). Both total area under the curve (AUC), 2-h AUC and AUC above baseline, and subjective appetite ratings were calculated. Results: No differences were observed in total PYYAUC between conditions, but hunger was reduced with INT (INT<EX; P<0.05), and satiety was increased with both SED and INT conditions (INT>EX and SED>EX; P<0.05). A correlation existed between the change in total PYY and insulin levels (r=-0.81; P<0.05), and total PYY and satiety(r=0.80; P<0.05) with the EX condition, not the SED and INT conditions. Conclusion: The total PYY response to meals is not altered over the course of a 12-h day with either intermittent or continuous exercise; however, intermittent exercise increased satiety and reduced hunger to a greater extent than continuous exercise in obese individuals.
Holmstrup, ME (Department of Exercise and Rehabilitative Sciences), KS Bruening, J Rozelle (2013) “Quantifying Accurate Calorie Estimation using the 'Think Aloud' Method”, Journal of Nutrition Education and Behavior. 45(1): 77-81; 2013.
Objective: Clients often have limited time in a nutrition education setting. An improved understanding of the strategies used to accurately estimate calories may help to identify areas of focused instruction to improve nutrition knowledge. Methods: A “Think Aloud” exercise was recorded during the estimation of calories in a standard dinner meal (415 kcal) in 15 nutrition-trained and 15 untrained subjects. Accuracy of participant estimation was assessed, and estimation strategies were compared in accurate vs inaccurate estimators. Results: Accurate participants were more likely to demonstrate an ability to convert between common portion size measurements and serving sizes, possess some knowledge of energy density, and properly implement basic math skills. Conclusions and Implications: The “Think Aloud” methodology was informative in assessing the cognitive processes behind a nutrition exercise, and further use is warranted. Focused instruction in portion size conversion, energy density, and the use of math skills may enhance calorie estimation accuracy.
Hrizo, Stacy L. (Department of Biology), Isaac J. Fisher, Daniel R. Long, Joshua A. Hutton (Department of Biology, majors), Zhaohui Liu, Michael J. Palladino (2013) “Early mitochondrial dysfunction leads to altered redox chemistry underlying pathogenesis of TPI deficiency”, Neurobiology of Disease, 54 (2013), 289-296.
Triose phosphate isomerase (TPI) is responsible for the interconversion of dihydroxyacetone phosphate to glyceraldehyde-3-phosphate in glycolysis. Point mutations in this gene are associated with a glycolytic enzymopathy called TPI deficiency. This study utilizes a Drosophila melanogaster model of TPI deficiency; TPIsugarkill is a mutant allele with a missense mutation (M80T) that causes phenotypes similar to human TPI deficiency. In this study, the redox status of TPIsugarkill flies was examined and manipulated to provide insight into the pathogenesis of this disease. Our data show that TPIsugarkill animals exhibit higher levels of the oxidized forms of NAD+, NADP+ and glutathione in an age-dependent manner. Additionally, we demonstrate that mitochondrial redox state is significantly more oxidized in TPIsugarkill animals. We hypothesized that TPIsugarkill animals may be more sensitive to oxidative stress and that this may underlie the progressive nature of disease pathogenesis. The effect of oxidizing and reducing stressors on behavioral phenotypes of the TPIsugarkill animals was tested. As predicted, oxidative stress worsened these phenotypes. Importantly, we discovered that reducing stress improved the behavioral and longevity phenotypes of the mutant organism without having an effect on TPIsugarkill protein levels. Overall, these data suggest that reduced activity of TPI leads to an oxidized redox state in these mutants and that the alleviation of this stress using reducing compounds can improve the mutant phenotypes.
Smith, K.A. (Department of Exercise and Rehabilitative Sciences). Gallagher, M., Hays, A.E., & Robertson, R. (2012) “Development of the physical activity index as a measure of total activity load and total kilocalorie expenditure during submaximal walking,” Journal of Physical Activity and Health, (9), 757-764
BACKGROUND: Pedometers are most accurate at measuring steps, less accurate at estimating distance, and even less accurate at estimating kilocalorie expenditure. The purpose of this investigation was to create a Physical Activity Index (PAI) using pedometer step counts and rating of perceived exertion (RPE) to enhance the ability to estimate kilocalorie expenditure during walking exercise. METHODS: Thirty-two females performed three counterbalanced walking bouts. During each bout, oxygen consumption, RPE, and step counts were measured. The PAI was calculated as the product of RPE and step count for each of the bouts. RESULTS: Concurrent validation of the PAI was established using VO2 as the criterion variable. A multiple regression analysis revealed a strong, positive relation between PAI score and VO2 (r = 0.91). Data were then used to develop a statistical model to estimate kcal expenditure using the PAI score as the predictor variable.
CONCLUSION: The PAI was found to be an accurate method of estimating kcal expenditure and is a simple, unobtrusive and inexpensive tool which may be used in public health settings.