Hope, Coping and Eco-Anxiety: Young People's Mental Health in a Climate-Impacted Australia.

(1) Background: In Australia, young people are one of the most vulnerable populations to the mental health impacts of climate change. The aim of this article was to explore mental health promotion issues related to climate change for young people in Australia. (2) Methods: An exploratory mixed-method approach, co-led by young people, was used to engage young people living in Australia aged 18-24 years in semi-structured interviews (N = 14) and an online survey (N = 46). Data were analysed thematically and with descriptive statistics. (3) Results: Findings indicated that negative impacts included worry, eco-anxiety, stress, hopelessness/powerlessness and feelings of not having a voice. Several mediating factors, in particular social media engagement, highlighted the duality of mental health impacts for young people's mental health. Positive impacts of climate action included feeling optimistic and in control. (4) Conclusions: This exploratory study contributes to an emerging field of public health research on young people's mental health in a climate-impacted Australia. Climate change is a significant concern for young people, and it can negatively affect their mental health. The findings can inform the design of public health interventions that raise awareness of climate change-related mental health issues among young people and promote their participation in nature-based interventions, climate action and empowering social media engagement.

Emulsion-based directed evolution of enzymes and proteins in yeast.

Emulsion-based selections are a unique type of directed evolution method that overcome common bottlenecks associated with purely in vivo selections. For example, emulsions including cell-free translation machinery can be useful for expression of toxic genes. However, not all cell types can efficiently produce protein in vitro, for example, the eukaryotic microbe Saccharomyces cerevisiae. compartmentalized self replication (CSR) and compartmentalized partnered replication (CPR) are two emulsion-based selection schemes that leverage the advantages of both in vivo and in vitro selections by compartmentalizing cells in water-in-oil droplets. Previous implementations of these methods utilized bacterial hosts, which has limited the technology to the directed evolution of proteins that can be heterologously expressed in prokaryotic systems. To expand the repertoire of targets that can be evolved, we have adapted emulsion-based PCR selections to be compatible with a eukaryotic host.

Direct Enzymatic Synthesis of a Deep-Blue Fluorescent Noncanonical Amino Acid from Azulene and Serine.

We report a simple, one-step enzymatic synthesis of the blue fluorescent noncanonical amino acid ß-(1-azulenyl)-l-alanine (AzAla). By using an engineered tryptophan synthase ß-subunit (TrpB), stereochemically pure AzAla can be synthesized at scale starting from commercially available azulene and l-serine. Mutation of a universally conserved catalytic glutamate in the active site to glycine has only a modest effect on native activity with indole but abolishes activity on azulene, suggesting that this glutamate activates azulene for nucleophilic attack by stabilization of the aromatic ion.

Compartmentalized partnered replication for the directed evolution of genetic parts and circuits.

Compartmentalized partnered replication (CPR) is an emulsion-based directed evolution method based on a robust and modular phenotype-genotype linkage. In contrast to other in vivo directed evolution approaches, CPR largely mitigates host fitness effects due to a relatively short expression time of the gene of interest. CPR is based on gene circuits in which the selection of a 'partner' function from a library leads to the production of a thermostable polymerase. After library preparation, bacteria produce partner proteins that can potentially lead to enhancement of transcription, translation, gene regulation, and other aspects of cellular metabolism that reinforce thermostable polymerase production. Individual cells are then trapped in water-in-oil emulsion droplets in the presence of primers and dNTPs, followed by the recovery of the partner genes via emulsion PCR. In this step, droplets with cells expressing partner proteins that promote polymerase production will produce higher copy numbers of the improved partner gene. The resulting partner genes can subsequently be recloned for the next round of selection. Here, we present a step-by-step guideline for the procedure by providing examples of (i) selection of T7 RNA polymerases that recognize orthogonal promoters and (ii) selection of tRNA for enhanced amber codon suppression. A single round of CPR should take ∼3-5 d, whereas a whole directed evolution can be performed in 3-10 rounds, depending on selection efficiency.

Anti-Markovnikov alkene oxidation by metal-oxo-mediated enzyme catalysis.

Catalytic anti-Markovnikov oxidation of alkene feedstocks could simplify synthetic routes to many important molecules and solve a long-standing challenge in chemistry. Here we report the engineering of a cytochrome P450 enzyme by directed evolution to catalyze metal-oxo-mediated anti-Markovnikov oxidation of styrenes with high efficiency. The enzyme uses dioxygen as the terminal oxidant and achieves selectivity for anti-Markovnikov oxidation over the kinetically favored alkene epoxidation by trapping high-energy intermediates and catalyzing an oxo transfer, including an enantioselective 1,2-hydride migration. The anti-Markovnikov oxygenase can be combined with other catalysts in synthetic metabolic pathways to access a variety of challenging anti-Markovnikov functionalization reactions.

Rapid and Inexpensive Evaluation of Nonstandard Amino Acid Incorporation in Escherichia coli.

By introducing engineered tRNA and aminoacyl-tRNA synthetase pairs into an organism, its genetic code can be expanded to incorporate nonstandard amino acids (nsAAs). The performance of these orthogonal translation systems (OTSs) varies greatly, however, with respect to the efficiency and accuracy of decoding a reassigned codon as the nsAA. To enable rapid and systematic comparisons of these critical parameters, we developed a toolkit for characterizing any Escherichia coli OTS that reassigns the amber stop codon (TAG). It assesses OTS performance by comparing how the fluorescence of strains carrying plasmids encoding a fused RFP-GFP reading frame, either with or without an intervening TAG codon, depends on the presence of the nsAA. We used this kit to (1) examine nsAA incorporation by seven different OTSs, (2) optimize nsAA concentration in growth media, (3) define the polyspecificity of an OTS, and (4) characterize evolved variants of amberless E. coli with improved growth rates.