The human milk protein-lipid complex HAMLET disrupts glycolysis and induces death in Streptococcus pneumoniae

HAMLET is a complex of human a-lactalbumin (ALA) and oleic acid and kills several Gram-positive bacteria by a mechanism that bears resemblance to apoptosis in eukaryotic cells. To identify HAMLET's bacterial targets, here we used Streptococcus pneumoniae as a model organism and employed a proteomic approach that identified several potential candidates. Two of these targets were the glycolytic enzymes fructose bis-phosphate aldolase (FBPA) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH). Treatment of pneumococci with HAMLET immediately inhibited their ATP and lactate production, suggesting that HAMLET inhibits glycolysis. This observation was supported by experiments with recombinant bacterial enzymes, along with biochemical and bacterial viability assays, indicating that HAMLET's activity is partially inhibited by high glucose-mediated stimulation of glycolysis but enhanced in the presence of the glycolysis inhibitor 2-deoxyglucose. Both HAMLET and ALA bound directly to each glycolytic enzyme in solution and solid phase assays and effectively inhibited their enzymatic activities. In contrast, oleic acid alone had little to no inhibitory activity. However, ALA alone also exhibited no bactericidal activity and did not block glycolysis in whole cells, suggesting a role for the lipid moiety in the internalization of HAMLET into the bacterial cells to reach its target(s). This was verified by inhibition of enzyme activity in whole cells after HAMLET but not ALA exposure. The results of this study suggest that part of HAMLET's antibacterial activity relates to its ability to target and inhibit glycolytic enzymes, providing an example of a natural antimicrobial agent that specifically targets glycolysis

Oral strength in subjects with unilateral cleft lip and palate

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Riparian Meadow Response to Modern Conservation Grazing Management.

Riparian meadows occupy a small proportion of the public lands in the western United States but they provide numerous ecosystem services, including the production of high-quality forage for livestock grazing. Modern conservation management strategies (e.g., reductions in livestock stocking rates and adoption of new riparian grazing standards) have been implemented to better balance riparian conservation and livestock production objectives on publicly managed lands. We examined potential relationships between long-term changes in plant community, livestock grazing pressure and environmental conditions at two spatial scales in meadows grazed under conservation management strategies. Changes in plant community were not associated with either livestock stocking rate or precipitation at the grazing allotment (i.e., administrative) scale. Alternatively, both grazing pressure and precipitation had significant, albeit modest, associations with changes in plant community at the meadow (i.e., ecological site) scale. These results suggest that reductions in stocking rate have improved the balance between riparian conservation and livestock production goals. However, associations between elevation, site wetness, precipitation, and changes in plant community suggest that changing climate conditions (e.g., reduced snowpack and changes in timing of snowmelt) could trigger shifts in plant communities, potentially impacting both conservation and agricultural services (e.g., livestock and forage production). Therefore, adaptive, site-specific management strategies are required to meet grazing pressure limits and safeguard ecosystem services within individual meadows, especially under more variable climate conditions

Comparing Tangible Symbols, Picture Exchange and a Direct Selection Response when Teaching Requesting to Two Children with Autism Spectrum Disorder

Children diagnosed with Autism Spectrum Disorder (ASD) who fail to develop functional speech are candidates for augmentative and alternative communication (AAC) systems. One of the primary intentions of AAC is to provide an alternative method of communicating in the absence of speech (Mirenda, 2003). In order to select the most beneficial AAC system for a user, in regards to the ease of acquisition and successfully communicating with AAC systems, it is considered important to undertake research comparing various AAC systems and to assess users’ preferences for using one system over another. Empirical evidence from previous studies comparing AAC indicates that users often learn to use AAC systems with varying degrees of proficiency and at various acquisition rates. Additionally, assessing users’ preferences for different AAC systems has been shown to influence acquisition rates and long term maintenance of AAC systems and is suggested to be an important component when carrying out AAC intervention. In the present study a tangible symbol (TS) communication system was compared, in terms of acquisition rates and preference, with Picture Exchange (PE) and an additional direct selection (DS) method of gaining access to desired stimuli in two young boys with ASD. Two male participants diagnosed with ASD were taught via systematic instructional procedures to request/gain access to the continuation of preferred cartoon movies by using TS, PE, and DS. Additionally, preference assessments were implemented during intervention and follow-up phases to determine whether the participants showed a preference for using one of these three requesting/access methods over the other two, and whether any such preferences remained stable throughout follow-up sessions. Results indicated that both participants successfully learned to request each of the six cartoon movies using each of the three methods. Specifically, acquisition rates for TS and PE were comparable across both participants, and overall both participants preferred to request using the TS. During intervention sessions, one participant preferred to use DS, however this preference changed during follow-up where he chose to use TS more overall. These data suggest that TS is a viable AAC option for children with ASD who do not speak, and can be learned to a high proficiency after receiving systematic teaching procedures as used in the present study

A novel pupillometric method for indexing word difficulty in adults with and without aphasia

It is well documented that there are many potential confounds in assessing linguistic abilities individuals with stroke and brain injury. Such individuals often have impairments of attention, vision, and motor function, concurrent with impairments of language (Hallowell, 1999; Heuer & Hallowell, 2007; Heuer & Hallowell, 2009; Hallowell, Wertz, & Kruse, 2002). A set of measures that may aid in reducing these confounds entails task-evoked responses of the pupil (TERPs). TERPs are “a time-locked averaged record of pupillary dilation and constriction occurring during the performance of a mental task” (Ahern & Beatty, 1981, p. 122), which occur after the onset of processing (within 100-200 msec) and subside quickly following the termination of processing (Beatty, 1982). Kahneman (1973) highlighted the validity of pupillometric measures of “mental effort” (p. 18). The notion that greater cognitive or linguistic task difficulty leads to greater intensity of effort that can be captured through pupillometric indices has been affirmed through the results of studies on memory load (Kahneman & Beatty, 1966), mental arithmetic (Hess & Polt, 1964), letter discrimination (Beatty & Wagoner, 1978) , sentence repetition (Piquado, Isaacowitz, & Wingfield, 2010), sentence comprehension (Just & Carpenter, 1993), and cross-linguistic interpretation (Hyönä, Tommola, & Alaja, 1995). When experimenters carefully control participant characteristics, stimulus features, and environmental conditions, TERPs potentially provide valuable information regarding individual differences in cognitive and linguistic abilities

Lock-in thermography as a tool for fatigue damage monitoring of composite structures

International audienceFatigue dimensioning of composite structures has become a great challenge in the aeronautic industry. The estimation of the fatigue limit requires time-consuming experimental campaigns: millions of mechanical cycles are applied to one studied sample until failure, for several load levels. The alternative discussed in the present paper is to monitor the self-heating of carbon/epoxy composites under a significantly reduced number of load cycles, in order to define fatigue damage indicators. The chosen approach is to use lock-in thermography, which makes it possible to analyse the first harmonics of the heating signal, not matter how noisy it might be