"Just add small molecules" cell-free protein synthesis: Combining DNA template and cell extract preparation into a single fermentation.

Cell-free protein synthesis (CFPS) is a versatile biotechnology platform enabling a broad range of applications including clinical diagnostics, large-scale production of officinal therapeutics, small-scale on-demand production of personal magistral therapeutics, and exploratory research. The shelf stability and scalability of CFPS systems also have the potential to overcome cost and infrastructure challenges for distributing and using essential medical tests at home in both high- and low-income countries. However, CFPS systems are often more time-consuming and expensive to prepare than traditional in vivo systems, limiting their broader use. Much work has been done to lower CFPS costs by optimizing cell extract preparation, small molecule reagent recipes, and DNA template preparation. In order to further reduce reagent cost and preparation time, this work presents a CFPS system that does not require separately purified DNA template. Instead, a DNA plasmid encoding the recombinant protein is transformed into the cells used to make the extract, and the extract preparation process is modified to allow enough DNA to withstand homogenization-induced shearing. The finished extract contains sufficient levels of intact DNA plasmid for the CFPS system to operate. For a 10 mL scale CFPS system expressing recombinant sfGFP protein for a biosensor, this new system reduces reagent cost by more than half. This system is applied to a proof-of-concept glutamine sensor compatible with smartphone quantification to demonstrate its viability for further cost reduction and use in low-resource settings.

Modality-specific tracking of attention and sensory statistics in the human electrophysiological spectral exponent.

A hallmark of electrophysiological brain activity is its 1/f-like spectrum - power decreases with increasing frequency. The steepness of this 'roll-off' is approximated by the spectral exponent, which in invasively recorded neural populations reflects the balance of excitatory to inhibitory neural activity (E:I balance). Here, we first establish that the spectral exponent of non-invasive electroencephalography (EEG) recordings is highly sensitive to general (i.e., anaesthesia-driven) changes in E:I balance. Building on the EEG spectral exponent as a viable marker of E:I, we then demonstrate its sensitivity to the focus of selective attention in an EEG experiment during which participants detected targets in simultaneous audio-visual noise. In addition to these endogenous changes in E:I balance, EEG spectral exponents over auditory and visual sensory cortices also tracked auditory and visual stimulus spectral exponents, respectively. Individuals' degree of this selective stimulus-brain coupling in spectral exponents predicted behavioural performance. Our results highlight the rich information contained in 1/f-like neural activity, providing a window into diverse neural processes previously thought to be inaccessible in non-invasive human recordings.

Mediating effects of stress, weight-related issues, and depression on suicidality in college students.

OBJECTIVE: Through a holistic health lens, the current study examines the effects of weight-related issues and stress on suicidality while controlling for depressive symptoms in college students. PARTICIPANTS: In total, 872 undergraduate and graduate students at DePaul University completed the American College Health Association-National College Health Assessment II Web-based survey in Spring 2010. METHODS: Measures of suicidality, depression, weight-related issues, and life stressors were assessed, along with gender differences. RESULTS: Females reported experiencing more weight loss attempts and total stressors than males. Weight-related issues and stress both significantly predicted depressive symptoms in a path analysis; depressive symptoms, in turn, significantly predicted suicidality. Gender differences were found; depressive symptoms mediate the relation between stress and suicidal behavior for females but not for males. IMPLICATIONS: This investigation furthers previous research on suicidality in college students and suggests that all-inclusive interventions that address weight-related issues and stress may help reduce depressive symptoms, which then may reduce suicidal behavior.