Biology subjects

Steadman, D.

Publications and source records attributed to Steadman, D..

2 recordsLinked to original sources

bioRxiv2021

Defining 'Destructive fishing': a lack of consensus inhibits effective global policy

The term "destructive fishing" appears in multiple international policy instruments intended to improve outcomes for marine biodiversity, coastal communities and sustainable fisheries. However, the meaning of "destructive fishing" is often vague, limiting effectiveness in policy. Therefore, in this study we systematically reviewed the use of "destructive fishing" in three record types: academic literature, media articles, and policy documents between 1976-2020. A more detailed analysis was performed on sub-sets of these records, considering the extent to which the term is characterised, geographic distribution of use, and specific impacts and practices associated with the term. We found that use of "destructive fishing" relative to the generic term fisheries has increased since the 1990s. Records focused predominantly on fishing practices in South-eastern Asia, followed by Southern Asia and Europe. The term was characterised in detail in only 15% of records. Habitat damage and blast/poison fishing were the most associated ecological impacts and gear/practices, respectively. Bottom trawling and unspecified net fishing were regularly linked to destructive fishing. Importantly, the three record types use the term differently. Academic literature tends to specifically articulate the negative impacts, while media articles focus generally on associated gears/practices. Significant regional variation also exists in how the term is used and what phenomena it is applied to. This study provides evidence and recommendations to inform stakeholders in any future pursuit of a unified definition of "destructive fishing" to support more meaningful implementation of global sustainability goals.

ecology↗

bioRxiv2019

Simultaneous optimization of donor and acceptor substrate specificity for transketolase by a small but smart library

A narrow substrate range is a major limitation in exploiting enzymes more widely as catalysts in synthetic organic chemistry. For enzymes using two substrates, the simultaneous optimization of both substrate specificities, is also required for the rapid expansion of accepted substrates. Transketolase catalyses the reversible transfer of a C2-ketol unit from a donor substrate to an aldehyde acceptor and suffers the limitation of narrow substrate scope for widely industrial applications. Herein, transketolase from E. coli was engineered to simultaneously accept both pyruvate as a novel donor substrate, and unnatural acceptor aldehydes, including propanal, pentanal, hexanal and 3-formylbenzoic acid. Twenty single-mutant variants were firstly designed and characterized experimentally. Beneficial mutations were then recombined to construct a small but smart library. Screening of this library identified the best variant with a 9.2-fold improvement in the yield towards pyruvate and propionaldehyde, relative to WT. Pentanal and hexanal were used as acceptors to determine stereoselectivities of the reactions, which were found to be higher than 98% ee for the S configuration. Three variants were identified to be active for the reaction between pyruvate and 3-formylbenzoic acid. The best variant was able to convert 47% of substrate into product within 24 h, whereas no conversion was observed for WT. Docking experiments suggested a cooperation between the mutations responsible for donor and acceptor acceptances, that would promote the activity towards both the acceptor and donor. The variants obtained have the potential to be used for developing catalytic pathways to a diverse range of high-value products.

bioengineering↗