Detection of bacterial spores with lanthanide-macrocycle binary complexes

The detection of bacterial spores via dipicolinate-triggered lanthanide luminescence has been improved in terms of detection limit, stability, and susceptibility to interferents by use of lanthanide−macrocycle binary complexes. Specifically, we compared the effectiveness of Sm, Eu, Tb, and Dy complexes with the macrocycle 1,4,7,10-tetraazacyclododecane-1,7-diacetate (DO2A) to the corresponding lanthanide aquo ions. The Ln(DO2A)^+ binary complexes bind dipicolinic acid (DPA), a major constituent of bacterial spores, with greater affinity and demonstrate significant improvement in bacterial spore detection. Of the four luminescent lanthanides studied, the terbium complex exhibits the greatest dipicolinate binding affinity (100-fold greater than Tb^(3+) alone, and 10-fold greater than other Ln(DO2A)^+ complexes) and highest quantum yield. Moreover, the inclusion of DO2A extends the pH range over which Tb−DPA coordination is stable, reduces the interference of calcium ions nearly 5-fold, and mitigates phosphate interference 1000-fold compared to free terbium alone. In addition, detection of Bacillus atrophaeus bacterial spores was improved by the use of Tb(DO2A)^+, yielding a 3-fold increase in the signal-to-noise ratio over Tb^(3+). Out of the eight cases investigated, the Tb(DO2A)^+ binary complex is best for the detection of bacterial spores

Ecosystem Food Web Lift-the-Flap Pages

In the lesson on which this practical article is based, third grade students constructed a “lift-the-flap” page to explore food webs on the prairie. The moveable papercraft focused student attention on prairie animals’ external structures and how the inferred functions of those structures could support further inferences about the animals’ diets. In general, most students made simple causal connections between an animal’s observable characteristics and the food it would probably eat. Some students were also able to make multi-agent connections to develop a more complex mental model of a food web. Ultimately, the lift-the flap project was engaging to students and motivated them to focus their attention on the characteristics of animals of different ecosystems to infer their probable diets

The Association Between Discrimination and Sleep is Exacerbated in Individuals with Comorbid Chronic Health Conditions

Introduction: The consequences of recurrent, stressful daily experiences for sleep health appear intensified in individuals with pre-existing health conditions. Although discrimination has been associated with sleep outcomes, the role of comorbid chronic health conditions (CCHCs), and impact of perceived discrimination, remains unclear. The present study investigated (1) the associations between daily discrimination and sleep and (2) moderating roles of CCHCs and daily life interference and hardship. Methods: The current study utilized archival data from the Midlife in the United States (MIDUS) Study II. Participants, 174 adults (51% female, Mage=57 yrs., SD=11.5 yrs.), completed 7 days of actigraphy, sleep diary, PSQI, and CCHC-reporting measures. Models examined the moderating effects of CCHCs, daily interference, and hardship on the association between discrimination and sleep. Results: Daily discriminatory experiences predicted numerous poor sleep outcomes, exacerbated for persons with higher CCHCs. Higher comorbidity (95% CI=5.40, 68.75) exacerbated the association between discrimination and TSTactigraphy, further strengthened by perceived hardship (95% CI=-3.75, -.40) and interference (95% CI=-3.65, -.30). Number of CCHCs, qualified by perceived hardship (95% CI=.00, .04) and interference (95% CI=.01, .05), predicted diary sleep quality above discrimination. The interaction between CCHCs and hardship predicted global PSQI scores (95% CI=-.91, -.12) beyond discrimination. Conclusion: Daily experiences of discrimination are associated with decreased sleep duration and quality. These associations were stronger for individuals with multiple CCHCs. Exacerbating CCHC effects were perpetuated by perceived interference and hardships, suggesting individual emotion regulation (ER) differences. Future research should attend to sleep-related consequences of differential discrimination-informed ER by persons with CCHCs.https://scholarscompass.vcu.edu/gradposters/1042/thumbnail.jp

Daily Physical Activity and Bone Health Among High School Students

With advancements in healthcare and public education, life expectancy is increasing and the prevalence of age related health conditions such as osteoporosis are rising. It is well known that children and adolescents who engage in healthy behaviors are more likely to carry those behaviors into adulthood. More specifically, children and adolescents who engage in weight bearing physical activity have higher bone density and are less likely to develop osteoporosis later in life. Furthermore, technology that measures daily physical activity is improving and individuals are interested in the amount of activity they and their children should participate in to remain healthy. The primary focus of this study was to quantify the association between pedometer-based physical activity and various measures of bone mass in adolescents. A secondary purpose of this investigation was to determine if adolescents who took at least 10,000 steps per day exhibited higher bone mass compared to those who took less than 10,000 steps per day

Biomonitoring Data for 2,4-Dichlorophenoxyacetic Acid in the United States and Canada: Interpretation in a Public Health Risk Assessment Context Using Biomonitoring Equivalents

Background: Several extensive studies of exposure to 2,4- dichlorophenoxyacetic acid (2,4-D) using urinary concentrations in samples from the general population, farm applicators, and farm family members are now available. Reference doses (RfDs) exist for 2,4-D, and Biomonitoring Equivalents (BEs; concentrations in urine or plasma that are consistent with those RfDs) for 2,4-D have recently been derived and published. Objective: We reviewed the available biomonitoring data for 2,4-D from the United States and Canada and compared them with BE values to draw conclusions regarding the margin of safety for 2,4-D exposures within each population group. Data sources: Data on urinary 2,4-D excretion in general and target populations from recent published studies are tabulated and the derivation of BE values for 2,4-D summarized. Data synthesis: The biomonitoring data indicate margins of safety (ratio of BE value to biomarker concentration) of approximately 200 at the central tendency and 50 at the extremes in the general population. Median exposures for applicators and their family members during periods of use appear to be well within acute exposure guidance values. Conclusions: Biomonitoring data from these studies indicate that current exposures to 2,4-D are below applicable exposure guidance values. This review demonstrates the value of biomonitoring data in assessing population exposures in the context of existing risk assessments using the BE approach. Risk managers can use this approach to integrate the available biomonitoring data into an overall assessment of current risk management practices for 2,4-D

The effects of anthropogenic noise and urban habitats on song structure in a vocal mimic; the gray catbird (Dumetella carolinensis) sings higher frequencies in noisier habitats

In urban and human-modified landscapes, animals face novel selection pressures resulting from differences in habitat structure and increased anthropogenic noise. Urban noise pollution can negatively impact songbirds because low-frequency noise often masks portions of birds’ mating signals and reduces signal transmission. Previous research has demonstrated that the songs of birds in more urban habitats have structural differences that can enhance signal transmission when noise is present. The majority of these studies have focused on species that deliver short, stereotyped songs and have limited repertoires. Gray catbirds (Dumetella carolinensis, family: Mimidae) sing long bouts containing imitated, improvised, and invented song elements, and therefore may have an increased ability to vary songs in response to noise. We hypothesized that aspects of developed habitats including loud anthropogenic noise and changes to land cover would impact catbirds’ song structural parameters, including song minimum, peak, and maximum frequency, frequency bandwidth, and entropy. We recorded and processed songs from 42 male catbirds and analyzed over 18,000 song elements from sites along an urban gradient from western Virginia to the Washington, DC metropolitan region. We quantified the urban intensity at each site-centroid based on percent canopy cover, percent impervious surface, and noise level. Song features such as minimum, maximum, and peak frequency increased significantly as noise levels increased, demonstrating that catbirds in noisier areas sing higher frequency songs compared to individuals in quieter habitats. Land cover variables also significantly predicted certain song features such as maximum frequency (impervious surface) or entropy (canopy cover). These structural differences in catbird song can limit the negative effects of environmental noise-masking, even for their long song bouts, and suggest that vocal mimics respond to anthropogenic noise. Future studies could investigate repertoire size and composition along an urban gradient and if these structural differences lead to functional consequences for the songs of vocal mimics

The Phenotypic Effects of Royal Jelly on Wild-Type \u3cem\u3eD. melanogaster\u3c/em\u3e Are Strain-Specific

The role for royal jelly (RJ) in promoting caste differentiation of honeybee larvae into queens rather than workers is well characterized. A recent study demonstrated that this poorly understood complex nutrition drives strikingly similar phenotypic effects in Drosophila melanogaster, such as increased body size and reduced developmental time, making possible the use of D. melanogaster as a model system for the genetic analysis of the cellular mechanisms underlying RJ and caste differentiation. We demonstrate here that RJ increases the body size of some wild-type strains of D. melanogaster but not others, and report significant delays in developmental time in all flies reared on RJ. These findings suggest that cryptic genetic variation may be a factor in the D. melanogaster response to RJ, and should be considered when attempting to elucidate response mechanisms to environmental changes in non-honeybee species

Spectroscopic Analysis of Ligand Binding to Lanthanide−Macrocycle Platforms

A high-affinity, binary Eu^(3+) receptor site consisting of 1,4,7,10-tetraazacyclododecane-1,7-diacetate (DO2A) was constructed with the goal of improving the detection of dipicolinic acid (DPA), a major component of bacterial spores. Ternary Eu(DO2A)(DPA)− complex solutions (1.0 µM crystallographically characterized TBA·Eu(DO2A)(DPA)) were titrated with EuCl_3 (1.0 nM−1.0 mM); increased Eu^(3+) concentration resulted in a shift in equilibrium population from Eu(DO2A)(DPA)^− to Eu(DO2A)^+ and Eu(DPA)^+, which was monitored via the ligand field sensitive ^5D_0 → ^7F_3 transition (λ_(em) = 670−700 nm) using luminescence spectroscopy. A best fit of luminescence intensity titration data to a two-state thermodynamic model yielded the competition equilibrium constant (K_c), which in conjunction with independent measurement of the Eu(DPA)^+ formation constant (K_a) allowed calculation of the ternary complex formation constant (K_a^′). With this binding affinity by competition (BAC) assay, we determined that K_a^′ = 10^(8.21) M^(−1), which is ∼1 order of magnitude greater than the formation of Eu(DPA)^+. In general, the BAC assay can be employed to determine ligand binding constants of systems where the lanthanide platform (usually a binary complex) is stable and the ligand bound versus unbound states can be spectroscopically distinguished