1,256 research outputs found
Sexual development of wild and mass-reared male Queensland fruit flies in response to natural food sources
Diet has a profound influence on the fitness of adult tephritid flies. Mass-reared flies are provided yeast hydrolysate as a rich source of nutrition that supports rapid sexual development and mating success. In contrast, wild tephritid flies often live in environments where food may be hard to find,
and these are the conditions that sexually immature mass-reared sterile males encounter when released into the field during sterile insect technique campaigns. The effect of natural food sources (bat guano, bird droppings, citrus pollen, and wheat pollen) on the sexual development of adult mass-reared fertile, mass-reared sterile, and wild male Queensland fruit flies, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), was determined bymeasuring ejaculatory apodeme size. Inclusion of yeast hydrolysate in the adult diet was associated with faster growth of the ejaculatory apodeme in comparison with all other diets. Effects of diet were far less pronounced in mass-reared males, which may indicate reduced nutritional requirements, whereas the ejaculatory apodeme of wild males fed
on natural sources of food or sucrose alone did not increase in size over the first 20 days of adult life
The Association Between Abdominal Fat, Cardiorespiratory Fitness, and Clinical Markers of Metabolic Syndrome
Our purpose was to determine the association between abdominal fat and cardiorespiratory fitness (CRF) on markers of metabolic syndrome (MetS) total cholesterol (TC), high-density lipoprotein (HDL-C), low-density lipoprotein (LDL-C), triglycerides (TG), glucose, and blood pressure. We conducted a retrospective study on 165 adults (108 men) in which correlations between waist girth (WG), CRF and blood variables were determined. The cohort was partitioned by gender into quartiles and again by WG and differences in markers of MetS were compared across quartiles by ANOVA and by ANCOVA to determine the influence of CRF. Males in the lowest WG quartile exhibited greater HDL-C and lower diastolic blood pressure vs. the highest quartile (p < 0.05). TG were lower in the lowest vs. the third and highest quartile (p < 0.05), and glucose was greater in the highest vs. the first and second quartiles (p < 0.05). Females in the second WG quartile exhibited higher HDL-C vs. the highest quartile, and TG, glucose, systolic and diastolic blood pressure were lower in the lowest vs. the highest quartile (p < 0.05). After adjusting for CRF, diastolic blood pressure across WG in males were no longer significant, and HLD-C and TG quartile differences were no longer significant in females. We confirm WG as an important correlate of clinical markers of MetS in adults. CRF mitigates relationships between WG and clinical markers of cardio-metabolic risk in men and women
Aggregation of Staphylococcus aureus following treatment with the antibacterial flavonol galangin.
Aim: The flavonol galangin, an antimicrobial constituent of the traditional medicines propolis and Helichrysum aureonitens, is being assessed as part of an ongoing investigation into the antibacterial activity of flavonoids. The present study sought to establish whether galangin has any aggregatory effect on bacterial cells. Methods and Results: In preparatory time-kill assays, 50 μg ml-1 of galangin was found to reduce colony counts of c. 5 × 107 CFU ml-1Staphylococcus aureus NCTC 6571 by approximately 15 000-fold during 60 min of incubation. Subsequent light microscopy studies demonstrated significant increases in the number of large clusters of bacterial cells in populations treated with the flavonol. Conclusion: Data presented here show that galangin causes aggregation of bacterial cells. Significance and Impact of the Study: The finding that galangin causes bacterial cells to clump together may implicate the cytoplasmic membrane as a target site for this compound's activity. More importantly, this observation indicates that decreases in CFU numbers detected in time-kill and minimum bactericidal concentration (MBC) assays in previous investigations were at least partially attributable to this aggregatory effect. This raises the possibility that galangin is not genuinely bactericidal in action, and calls into question the suitability of time-kill and MBC assays for determining the nature of activity of naturally occurring flavonoids
Acute insulin response following exercise and its association to lipid changes in sedentary African-American women
Sedentary African-American (AA) women are at increased risk of hypertension, dyslipidemias, metabolic syndrome, and impaired insulin response to exercise. The purpose of the study was to determine the effects of a single bout of aerobic exercise on fasting serum insulin and glucose concentrations following 1464 kJ (350 kcal) of exercise and to determine if this response was associated with serum lipid concentrations in overweight AA women. Premenopausal AA women (n = 11, mean ± SD, age = 32.5 ± 4.8 yr., BMI = 29.8 ± 4.8 kg·m-2, % fat = 35.6 ± 6.3, VO2peak = 21.5 ± 3.6 ml·kg-1·min-1, total cholesterol = 4.8 ± 0.6 mmol·L-1, triglycerides = 0.60 ± 0.2 mmol·L-1, HDLC = 3.3 ± 0.5 mg·dL-1) performed 1464 kJ (350 kcal) of treadmill exercise at 60%-70%VO2peak. Fasting plasma insulin and glucose concentrations were collected 24-h prior to, and immediately, 24-h, and 48 h following exercise. Fasting insulin concentration increased immediately following exercise (Baseline=77.1 ± 10.42 vs. Immediately=117.4 ± 15.28 μU·mL-1, 95%CI= 32.71, 47.89; P<0.05). The change in insulin concentration from 24-h pre- to 24-h post-exercise was correlated with BMI (r= 0.51), VO2peak (r= -0.47), and the change in lipoprotein lipase activity (r=0.37) (P<0.05 for all). In conclusion, in sedentary AA women, the insulin response immediately following exercise may be elevated, and is not suppressed below pre-exercise concentrations during the 48-h following exercise. The insulin response 24-h following exercise is modestly associated with markers of lipoprotein metabolism
Sex differences in developmental response to yeast hydrolysate supplements in adult Queensland fruit fly
Post-teneral dietary supplements have been found to improve mating performance of male Bactrocera
tryoni (Froggatt) (Diptera: Tephritidae) (Q-fly) and show considerable promise for enhancement
of sterile insect technique (SIT) programmes even when applied within the current 48 h
pre-release holding period. However, Q-flies are released as a bisexual strain, and the positive effects
of a diet including yeast hydrolysate for males may also boost reproductive development and sexual
performance of females. Increased prevalence of mature sterile females can substantially dilute SIT
efficacy as mating capacity of sterile males is largely depleted by sterile females rather than the relatively
rare wild females. Here, we demonstrate that providing yeast hydrolysate for 48 h after adult
emergence, emulating the current pre-release holding period of Q-fly SIT, leads to a significant
increase in reproductive development and sexual performance inmale Q-flies. In contrast, female Qflies
with access to yeast hydrolysate for 48 h had ovaries that were poorly developed and, particularly
at younger ages, were less likely to mate and remate than females with continuous, ad libitum access
to yeast hydrolysate. Our findings suggest that addition of yeast hydrolysate into the pre-release diet
of Q-flies could be a cost-effective means of releasing a bisexual strain with competitive males but
with sexually immature females, thereby rendering it operationallymore similar to a unisexual strain
Dietary low-phytate mutant-M 955 barley grain alters phytate degradation and mineral digestion in sheep fed high-grain diets
Greater production demands for ruminants require increased dietary inclusion of high-energy feeds. Grains and oil seeds are most commonly used to enhance diet energy density. However, use of such feeds proportionally increases the amount of dietary phytate phosphorus (P), which the ruminant may not be able to fully utilise. Our objectives for this study were to determine the extent of phytate degradation and mineral digestion in wethers fed high-grain diets consisting of either a non-mutant or low-phytate mutant barley grain. In two separate experiments, mature Columbia wethers (n = 7) fitted with rumen and duodenal cannulas and Columbia × Polypay wether lambs (n = 8) were individually fed one of two finishing diets formulated with either non-mutant Harrington (HARR) variety or low-phytate mutant-M 955 (M955) barley grains. Total-P intake was similar (P=0.46–0.70) between the M955 and HARR treatments for mature (5756 and 5550 mg/day, respectively) and lamb (5207 and 4894 mg/day, respectively) wethers. Dietary water-soluble P was 3.6 times greater in M955 versus HARR diets and phytate P was 11 times greater in HARR versus M955 treatment diets. Apparent total-P digestion was similar between M955 and HARR treatments (P=0.52–0.69). More monoester P was identified in the duodenal chyme of mature wethers fed HARR treatment diet, presumably due to incomplete hydrolysis of phytate P in the rumen. Feeding M955, compared to HARR, treatment diet resulted in greater (P<0.05) apparent partial-tract digestion of calcium (Ca) and total-tract digestion of iron (Fe), magnesium (Mg), and zinc in mature wethers and apparent total-tract digestion of Mg and Fe and retention of Ca, Fe, and Mg in wether lambs. These results indicate that phytate in diets formulated with Harrington variety barley grain may not be fully digested in the rumen. Subsequent passage of partially digested phytate from the rumen may interfere with mineral digestion in wethers fed high-grain diets
Einstein's "Zur Elektrodynamik..." (1905) Revisited, with Some Consequences
Einstein, in his "Zur Elektrodynamik bewegter Korper", gave a physical
(operational) meaning to "time" of a remote event in describing "motion" by
introducing the concept of "synchronous stationary clocks located at different
places". But with regard to "place" in describing motion, he assumed without
analysis the concept of a system of co-ordinates. In the present paper, we
propose a way of giving physical (operational) meaning to the concepts of
"place" and "co-ordinate system", and show how the observer can define both the
place and time of a remote event. Following Einstein, we consider another
system "in uniform motion of translation relatively to the former". Without
assuming "the properties of homogeneity which we attribute to space and time",
we show that the definitions of space and time in the two systems are linearly
related. We deduce some novel consequences of our approach regarding
faster-than-light observers and particles, "one-way" and "two-way" velocities
of light, symmetry, the "group property" of inertial reference frames, length
contraction and time dilatation, and the "twin paradox". Finally, we point out
a flaw in Einstein's argument in the "Electrodynamical Part" of his paper and
show that the Lorentz force formula and Einstein's formula for transformation
of field quantities are mutually consistent. We show that for faster-than-light
bodies, a simple modification of Planck's formula for mass suffices. (Except
for the reference to Planck's formula, we restrict ourselves to Physics of
1905.)Comment: 55 pages, 4 figures, accepted for publication in "Foundations of
Physics
Spatially controlling neuronal adhesion and inflammatory reactions on implantable diamond
The mechanical and chemical properties of diamond and diamond-like carbon (DLC) coatings make them very suitable materials for improving the long-term performance of invasive electrode systems used in brain-computer interfaces (BCIs). We have performed in vitro testing to demonstrate methods for spatially directing neural cell growth and limiting the detrimental attachment of cells involved in the foreign body response on boron-doped diamond and DLC. Inkjet-printing, laser micro-machining, and stencil-assisted patterning techniques were used to control neuronal adhesion and modify inflammatory cell attachment. This work presents micro-tailored materials that could be used to improve the long-term quality of recorded signals from neural-electronic interfaces. © 2011 IEEE
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