Suchergebnisse

Directed evolution is a common tool employed to generate enzymes suitable for industrial use. High thermal stability is often advantageous or even a requirement for biocatalysts, as such the evolution of protein stability is of practical as well as academic interest. Even when evolving enzymes for new or improved catalytic functions, stability is an important factor since it can limit the accumulation rate and number of desired active site mutations. Dienelactone hydrolase, a small monomeric protein, has been previously evolved via a three-stage process to possess enhanced activity and specificity toward non-physiological substrates. In addition to seven active site mutations there were three surface mutations that were thought to increase the stability of the enzyme and compensate for the destabilizing active site mutations. Here, the individual influence of the three surface mutations--Q110L, Y137C and N154D--on the thermal and chemical stability of DLH has been assessed. While the Q110L and N154D mutations improved the thermal stability, the influence of the Y137C mutation was more complex. Individually it was destabilizing both thermally and chemically, but when in the presence of the Q110L and N154D mutations its effect was neutralized in relation to thermal but not chemical stability. In the context of a directed evolution experiment, these compensatory surface mutations play important roles. However, our results show that detrimental mutations can arise, thus the simultaneous monitoring of stability changes while evolving enzymes for enhanced catalytic properties can be beneficial. ; JLP is supported by an Australian Postgraduate Award from the Australian government and funding from the Research School of Chemistry, ANU.

Directed evolution is a common tool employed to generate enzymes suitable for industrial use. High thermal stability is often advantageous or even a requirement for biocatalysts, as such the evolution of protein stability is of practical as well as academic interest. Even when evolving enzymes for new or improved catalytic functions, stability is an important factor since it can limit the accumulation rate and number of desired active site mutations. Dienelactone hydrolase, a small monomeric protein, has been previously evolved via a three-stage process to possess enhanced activity and specificity toward non-physiological substrates. In addition to seven active site mutations there were three surface mutations that were thought to increase the stability of the enzyme and compensate for the destabilizing active site mutations. Here, the individual influence of the three surface mutations--Q110L, Y137C and N154D--on the thermal and chemical stability of DLH has been assessed. While the Q110L and N154D mutations improved the thermal stability, the influence of the Y137C mutation was more complex. Individually it was destabilizing both thermally and chemically, but when in the presence of the Q110L and N154D mutations its effect was neutralized in relation to thermal but not chemical stability. In the context of a directed evolution experiment, these compensatory surface mutations play important roles. However, our results show that detrimental mutations can arise, thus the simultaneous monitoring of stability changes while evolving enzymes for enhanced catalytic properties can be beneficial. ; JLP is supported by an Australian Postgraduate Award from the Australian government and funding from the Research School of Chemistry, ANU.

Abstract

Objectives
The impact of disasters on individual and community health can be extensive. As such, there exists the need to establish recovery measures that provides support psychologically and with additional mental health services and resilience building for affected people and their communities. Nature-led recovery is one such approach that has the ability to positively impact the mental health of people and their communities after a disaster. Nature-led recovery focuses on the social, economic and environmental recovery through activities that connect people and their communities to nature and the natural environment with the aim to foster recovery after a disaster. Nature-led recovery initiatives support the connection of people with nature and the natural environment to support such recovery processes. This review considers both community and government-led responses pertaining to nature-led recovery. The aim of this review is to systematically explore the literature on the impact of nature-led recovery initiatives on individual and community health following a disaster.


Content
This review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) following a three-step process of planning, conducting and reporting the review. At least three authors reviewed all eligible articles.


Summary
There was significant methodological heterogeneity between the sources identified (n=9). A narrative synthesis identified five key themes; A symbol of loss; Nature: the provider; Fostering community connectedness; Spiritual and emotional nourishment; and Regeneration leads to recovery.


Outlook
The positive benefits from nature-led recovery initiatives provide an opportunity to promote community connectedness and resilience following a disaster. Further research is needed to explore the implementation and evaluation of these initiatives for community recovery.

The ease with which enzymes can be adapted from their native roles and engineered to function specifically for industrial or commercial applications is crucial to enabling enzyme technology to advance beyond its current state. Directed evolution is a powerful tool for engineering enzymes with improved physical and catalytic properties and can be used to evolve enzymes where lack of structural information may thwart the use of rational design. In this study, we take the versatile and diverse α/β hydrolase fold framework, in the form of dienelactone hydrolase, and evolve it over three unique sequential evolutions with a total of 14 rounds of screening to generate a series of enzyme variants. The native enzyme has a low level of promiscuous activity toward p-nitrophenyl acetate but almost undetectable activity toward larger p-nitrophenyl esters. Using p-nitrophenyl acetate as an evolutionary intermediate, we have generated variants with altered specificity and catalytic activity up to 3 orders of magnitude higher than the native enzyme toward the larger nonphysiological p-nitrophenyl ester substrates. Several variants also possess increased stability resulting from the multidimensional approach to screening. Crystal structure analysis and substrate docking show how the enzyme active site changes over the course of the evolutions as either a direct or an indirect result of mutations. ; We acknowledge the Australian Research Council for funding and the staff at the BRF for performing the DNA sequencing. J.P. is supported by an Australian Postgraduate Award from the Australian government.

The ease with which enzymes can be adapted from their native roles and engineered to function specifically for industrial or commercial applications is crucial to enabling enzyme technology to advance beyond its current state. Directed evolution is a powerful tool for engineering enzymes with improved physical and catalytic properties and can be used to evolve enzymes where lack of structural information may thwart the use of rational design. In this study, we take the versatile and diverse α/β hydrolase fold framework, in the form of dienelactone hydrolase, and evolve it over three unique sequential evolutions with a total of 14 rounds of screening to generate a series of enzyme variants. The native enzyme has a low level of promiscuous activity toward p-nitrophenyl acetate but almost undetectable activity toward larger p-nitrophenyl esters. Using p-nitrophenyl acetate as an evolutionary intermediate, we have generated variants with altered specificity and catalytic activity up to 3 orders of magnitude higher than the native enzyme toward the larger nonphysiological p-nitrophenyl ester substrates. Several variants also possess increased stability resulting from the multidimensional approach to screening. Crystal structure analysis and substrate docking show how the enzyme active site changes over the course of the evolutions as either a direct or an indirect result of mutations. ; We acknowledge the Australian Research Council for funding and the staff at the BRF for performing the DNA sequencing. J.P. is supported by an Australian Postgraduate Award from the Australian government.

11 pages, 3 figures, 1 table, supplementary material https://doi.org/10.1126/sciadv.abm7452.-- Data and materials availability: All data needed to evaluate the conclusions in the paper are present in the paper, the Supplementary Materials, Dryad, and Zenodo ; Phylogenetic relationships and the timing of evolutionary events are essential for understanding evolution on longer time scales. Cheilostome bryozoans are a group of ubiquitous, species-rich, marine colonial organisms with an excellent fossil record but lack phylogenetic relationships inferred from molecular data. We present genome-skimmed data for 395 cheilostomes and combine these with 315 published sequences to infer relationships and the timing of key events among c. 500 cheilostome species. We find that named cheilostome genera and species are phylogenetically coherent, rendering fossil or contemporary specimens readily delimited using only skeletal morphology. Our phylogeny shows that parental care in the form of brooding evolved several times independently but was never lost in cheilostomes. Our fossil calibration, robust to varied assumptions, indicates that the cheilostome lineage and parental care therein could have Paleozoic origins, much older than the first known fossil record of cheilostomes in the Late Jurassic ; This project is funded by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement no. 724324 to L.H.L.). Extra funding for specific sampling expeditions were provided by the National Science Centre of Poland (grant PANIC/2016/23/B/ST10/01936 to P.K.), the ASSEMBLE Plus (Horizon 2020), the Leverhulme Trust (Research Project Award RPG-2016-429 to A.W.), the Russian Science Foundation (grant 18-14-00086 to A.N.O.), Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brazil [PQ-CNPq 308768/2018-3], Fundação de Amparo à Pesquisa do Estado de São Paulo, Brazil [FAPESP 19/17721-9] and the DISTANTCOM project (CTM2013-42667/ANT to C. Avila). B.F. was supported by Beatriu de Pinós (2019-BP-00183), funded by the AGAUR (Government of Catalonia) and by the Horizon 2020 programme under the Marie Skłodowska-Curie grant (no. 801370). The CAML-CEAMARC cruise of RV Aurora Australis (IPY project no. 53) were supported by the Australian Antarctic Division, the Japanese Science Foundation, the French Polar Institute IPEV, and the Muséum national d'Histoire naturelle, led by voyage leader, M. Riddle ; With the institutional support of the 'Severo Ochoa Centre of Excellence' accreditation (CEX2019-000928-S) ; Peer reviewed