Towards understanding the mechanism of n-hexane tolerance in Synechocystis sp.PCC 6803

Synthetic biology efforts have also led to the development of photosynthetic cyanobacteria as"autotrophic cell factories"for biosynthesis of various biofuels directly from CO_(2).However,the low tolerance to toxicity of biofuels has restricted the economic application of cyanobacterial hosts.In this study,RNAseq transcriptomics was employed to reveal stress responses to exogenous n-hexane in Synechocystis sp.PCC 6803.Functional enrichment analysis of the transcriptomic data showed that signal transduction systems were induced significantly.To further identify regulatory genes related to n-hexane tolerance,a library of transcriptional regulators(TRs)deletion mutants was then screened for their roles in nhexane tolerance.The results showed that a knockout mutant of slr0724 that encodes an Hta R suppressor protein was more tolerant to n-hexane than the wild type,indicating the involvement of slr0724 in nhexane tolerance.This study provides the foundation for better understanding the cellular responses to n-hexane in Synechocystis sp.PCC 6803,which could contribute to the further engineering of nhexane tolerance in cyanobacteria.

Deciphering and engineering high-light tolerant cyanobacteria for efficient photosynthetic cell factories

Development and utilization of“liquid sunshine”could be one of key solutions to deal with the issues of fossil fuel depletion and increasing carbon dioxide.Cyanobacteria are the only prokaryotes capable of performing oxygenic photosynthesis,and their activity accounts for~25%of the total carbon fixation on earth.More importantly,besides their traditional roles as primary producers,cyanobacteria could be modified as“photosynthetic cell factories”to produce renewable fuels and chemicals directly from CO_(2) driven by solar energy,with the aid of cutting-edging synthetic biology technology.Towards their large-scale biotechnological application in the future,many challenges still need to be properly addressed,among which is cyanobacterial cell factories inevitably suffer from high light(HL)stress during large-scale outdoor cultivation,resulting in photodamage and even cell death,limiting their productivity.In this review,we critically summarized recent progress on deciphering molecular mechanisms to HL and developing HL-tolerant chassis in cyanobacteria,aiming at facilitating construction of HLresistant chassis and promote the future application of the large-scale outdoor cultivation of cyanobacterial cell factories.Finally,the future directions on cyanobacterial chassis engineering were discussed.

Challenges and recent progress in the governance of biosecurity risks in the era of synthetic biology

Considerable progress has been achieved in basic research and the biotechnological application of biological sciences in recent years.Synthetic biology integrates systems biology,engineering,computer science,and other disciplines to achieve the“modification of life”or even the“creation of life”via the redesign of existing natural systems or the development of new biological components and devices.However,the research and application of synthetic biology can create potential risks,such as aggravation of species with complex gene modifications,threats to species diversity,abuse of biological weapons,laboratory leaks,and man-made mutations.Without a suitable governance system,such research activities could result in harm to humans,plants,and animals,as well as to natural ecological systems.In this article,we first briefly summarize technical progress in synthetic biology in recent years and the potential bioethical and biosecurity risks,and then describe current international treaties,guidance documents,and national regulatory measures designed to address potential harm caused by the dual-use property of synthetic biology,including the Biological Weapons Convention,the Convention on Biological Diversity,and the Model Code of Conduct for Biological Scientists(Tianjin Biosecurity Guidelines for Codes of Conduct for Scientists).In addition,we also present some recommendations for better governance of synthetic biology research and applications in China,including strengthening the biosecurity capacity,improving the biosecurity regulatory system,and promoting multilevel international cooperation to effectively address the potential biosecurity risks of synthetic biology.

Synthetic biology:Recent progress,biosafety and biosecurity concerns,and possible solutions

Synthetic biology is a new interdisciplinary research area that uses engineering principles as guidelines for biological investigation.With research goals to modify existing biological systems or to create new ones,the recent applications of synthetic biology have expanded approaches and tools for conventional biological research.In this article,we first briefly review the development and progress of synthetic biology over the past decade.Although the contributions of synthetic biology to basic life science research,human health,environmental protection,and even economic growth have been widely observed,potential biosafety,biosecurity,and ethical risks related to synthetic biology have also emerged in recent years as technology becomes less expensive,more mature,and more accessible.We provide a brief assessment of the risks associated with the possible misuse or abuse of this technology in various areas and discuss concerns from three points of view:biosafety,biosecurity risks,and ethics.Finally,to address challenges arising from the rapid progress of synthetic biology,technical,ethical,and regulatory measures were developed or discussed in recent years,including laboratory level precautionary measures for biosafety and biosecurity related to synthetic biology(such as genetic safeguards and firewalls),ethical codes of conduct for biological scientists,and regulations or oversight rules from personal,national,and international perspectives.A brief summary of these efforts is provided.