Parenting around child snacking: development of a theoretically-guided, empirically informed conceptual model

BackgroundSnacking contributes to excessive energy intakes in children. Yet factors shaping child snacking are virtually unstudied. This study examines food parenting practices specific to child snacking among low-income caregivers.MethodsSemi-structured interviews were conducted in English or Spanish with 60 low-income caregivers of preschool-aged children (18 non-Hispanic white, 22 African American/Black, 20 Hispanic; 92% mothers). A structured interview guide was used to solicit caregivers’ definitions of snacking and strategies they use to decide what, when and how much snack their child eats. Interviews were audio-recorded, transcribed verbatim and analyzed using an iterative theory-based and grounded approach. A conceptual model of food parenting specific to child snacking was developed to summarize the findings and inform future research.ResultsCaregivers’ descriptions of food parenting practices specific to child snacking were consistent with previous models of food parenting developed based on expert opinion [1, 2]. A few noteworthy differences however emerged. More than half of participants mentioned permissive feeding approaches (e.g., my child is the boss when it comes to snacks). As a result, permissive feeding was included as a higher order feeding dimension in the resulting model. In addition, a number of novel feeding approaches specific to child snacking emerged including child-centered provision of snacks (i.e., responding to a child’s hunger cues when making decisions about snacks), parent unilateral decision making (i.e., making decisions about a child’s snacks without any input from the child), and excessive monitoring of snacks (i.e., monitoring all snacks provided to and consumed by the child). The resulting conceptual model includes four higher order feeding dimensions including autonomy support, coercive control, structure and permissiveness and 20 sub-dimensions. Conclusions: This study formulates a language around food parenting practices specific to child snacking, identifies dominant constructs, and proposes a conceptual framework to guide future research

Characterisation of silent and active genes for a variable large protein of Borrelia recurrentis

BACKGROUND: We report the characterisation of the variable large protein (vlp) gene expressed by clinical isolate A1 of Borrelia recurrentis; the agent of the life-threatening disease louse-borne relapsing fever. METHODS: The major vlp protein of this isolate was characterised and a DNA probe created. Use of this together with standard molecular methods was used to determine the location of the vlp1(B. recurrentis A1) gene in both this and other isolates. RESULTS: This isolate was found to carry silent and expressed copies of the vlp1(B. recurrentis A1) gene on plasmids of 54 kbp and 24 kbp respectively, whereas a different isolate, A17, had only the silent vlp1(B. recurrentis A17) on a 54 kbp plasmid. Silent and expressed vlp1 have identical mature protein coding regions but have different 5' regions, both containing different potential lipoprotein leader sequences. Only one form of vlp1 is transcribed in the A1 isolate of B. recurrentis, yet both 5' upstream sequences of this vlp1 gene possess features of bacterial promoters. CONCLUSION: Taken together these results suggest that antigenic variation in B. recurrentis may result from recombination of variable large and small protein genes at the junction between lipoprotein leader sequence and mature protein coding region. However, this hypothetical model needs to be validated by further identification of expressed and silent variant protein genes in other B. recurrentis isolates

Effect of Levels of Acetate on the Mevalonate Pathway of Borrelia burgdorferi

Borrelia burgdorferi, the agent of Lyme disease, is a spirochetal pathogen with limited metabolic capabilities that survives under highly disparate host-specific conditions. However, the borrelial genome encodes several proteins of the mevalonate pathway (MP) that utilizes acetyl-CoA as a substrate leading to intermediate metabolites critical for biogenesis of peptidoglycan and post-translational modifications of proteins. In this study, we analyzed the MP and contributions of acetate in modulation of adaptive responses in B. burgdorferi. Reverse-transcription PCR revealed that components of the MP are transcribed as individual open reading frames. Immunoblot analysis using monospecific sera confirmed synthesis of members of the MP in B. burgdorferi. The rate-limiting step of the MP is mediated by HMG-CoA reductase (HMGR) via conversion of HMG-CoA to mevalonate. Recombinant borrelial HMGR exhibited a Km value of 132 µM with a Vmax of 1.94 µmol NADPH oxidized minute−1 (mg protein)−1 and was inhibited by statins. Total protein lysates from two different infectious, clonal isolates of B. burgdorferi grown under conditions that mimicked fed-ticks (pH 6.8/37°C) exhibited increased levels of HMGR while other members of the MP were elevated under unfed-tick (pH 7.6/23°C) conditions. Increased extra-cellular acetate gave rise to elevated levels of MP proteins along with RpoS, CsrABb and their respective regulons responsible for mediating vertebrate host-specific adaptation. Both lactone and acid forms of two different statins inhibited growth of B. burgdorferi strain B31, while overexpression of HMGR was able to partially overcome that inhibition. In summary, these studies on MP and contributions of acetate to host-specific adaptation have helped identify potential metabolic targets that can be manipulated to reduce the incidence of Lyme disease

Blood culture and stimulation conditions for the diagnosis of tuberculosis in cervids by the Cervigam assay

Mitogen- and antigen-induced interferon-γ (IFN-γ) responses of peripheral blood leucocytes from cervids were evaluated by a commercial whole-blood assay. The assay was applied to Mycobacterium bovis-infected white-tailed deer and reindeer, M bovis BCG-vaccinated white-tailed deer and elk, and unvaccinated, uninfected white-tailed deer, fallow deer, elk and reindeer. The responses of the M bovis-infected white-tailed deer to pokeweed mitogen (PWM) varied with time and between individuals. The responses of the M bovis-infected reindeer to PWM and M bovis purified protein derivative (PPD) were positively associated. Samples from tuberculosis-free captive herds in various parts of the USA were also evaluated. Four per cent of fallow deer, 20 per cent of elk, 44 per cent of white-tailed deer, and 91 per cent of reindeer had responses to PWM exceeding 0.25 Δ optical density, that is, PWM stimulation minus no stimulation. The specificity of the responses to M bovis PPD and a Mycobacterium tuberculosis complex-specific antigen rESAT-6:CFP-10, excluding animals not responding to PWM, ranged from 78 per cent to 100 per cent and was dependent upon the species and the positive response cut-off value. The results show that the commercial assay is valid for the detection of TB in reindeer; however, further development of the assay will be required before it is used in surveillance programs for white-tailed deer, fallow deer, and elk

Using a Portfolio Approach to Evaluate Animal Health Surveillance Portfolios in the United States

Selecting the optimal level of surveillance to implement for an animal disease is important when decision-makers are allocating resources within a surveillance portfolio (collection of all surveillance activities for a species). Decision-makers should consider economically efficient options that meet effectiveness requirements of a surveillance system (i.e., disease detection capability, timeliness, etc.). In this research, we look at components in two disease surveillance systems within a species portfolio and compare current surveillance testing levels with four other optional levels. Option 1 does not meet the detection capability thresholds, while option 2 meets thresholds for one disease but not the other. Options 3 and 4 meet the detection capability thresholds and result in a cost savings compared to current levels. We conclude that Option 3 would be the optimum level of surveillance as it has a lower cost-effectiveness ratio compared to option 4 and the current level, as well as a cost savings of $637,500

Characterization of Borrelia burgdorferi Isolated from Erythema Migrans Lesions: Interrelationship of Three Molecular Typing Methods

Genetic diversity among Borrelia burgdorferi isolates recovered from the skin of Lyme disease patients was assessed by ribosomal DNA (rDNA) spacer restriction fragment length polymorphism analysis, genomic restriction site polymorphism analysis, and plasmid content analysis. There was a significant association between the three rDNA spacer types, the six pulsed-field gel types, and plasmid content (P < 0.001). The association between distinct chromosomal and plasmid markers implies a clonal origin for each genotype