Selectable Markers and Reporter Genes for Engineering the Chloroplast of Chlamydomonas reinhardtii

Chlamydomonas reinhardtii is a model alga of increasing interest as a cell factory for the production of valuable compounds, including therapeutic proteins and bioactive metabolites. Expression of foreign genes in the chloroplast is particularly advantageous as: (i) accumulation of product in this sub-cellular compartment minimises potential toxicity to the rest of the cell; (ii) genes can integrate at specific loci of the chloroplast genome (plastome) by homologous recombination; (iii) the high ploidy of the plastome and the high-level expression of chloroplast genes can be exploited to achieve levels of recombinant protein as high as 5% total cell protein; (iv) the lack of any gene silencing mechanisms in the chloroplast ensures stable expression of transgenes. However, the generation of C. reinhardtii chloroplast transformants requires efficient methods of selection, and ideally methods for subsequent marker removal. Additionally, the use of reporter genes is critical to achieving a comprehensive understanding of gene expression, thereby informing experimental design for recombinant applications. This review discusses currently available selection and reporter systems for chloroplast engineering in C. reinhardtii, as well as those used for chloroplast engineering in higher plants and other microalgae, and looks to the future in terms of possible new markers and reporters that will further advance the C. reinhardtii chloroplast as an expression platform

Doing synthetic biology with photosynthetic microorganisms

The use of photosynthetic microbes as synthetic biology hosts for the sustainable production of commodity chemicals and even fuels has received increasing attention over the last decade. The number of studies published, tools implemented, and resources made available for microalgae have increased beyond expectations during the last few years. However, the tools available for genetic engineering in these organisms still lag those available for the more commonly used heterotrophic host organisms. In this mini-review, we provide an overview of the photosynthetic microbes most commonly used in synthetic biology studies, namely cyanobacteria, chlorophytes, eustigmatophytes and diatoms. We provide basic information on the techniques and tools available for each model group of organisms, we outline the state-of-the-art, and we list the synthetic biology tools that have been successfully used. We specifically focus on the latest CRISPR developments, as we believe that precision editing and advanced genetic engineering tools will be pivotal to the advancement of the field. Finally, we discuss the relative strengths and weaknesses of each group of organisms and examine the challenges that need to be overcome to achieve their synthetic biology potential.Peer reviewe

Vocational education and training and the therapeutic turn

The concept of 'therapeutic education' is being increasingly used in contemporary education policy studies to identify learning initiatives which are dominated by objectives linked to personal and social skills, emotional intelligence and building self-esteem. Contemporary educational goals connected with such strategies have been criticised for encouraging a 'victim culture' which marginalises learners and replaces the pursuit of knowledge and understanding with the development of personal values relevant to a life of social, cultural and economic risk and uncertainty. In relation to vocational education and training (VET) and post-school policy trends in particular, Hayes has argued that preparation for work has abandoned vocational/occupational knowledge and skills in favour of providing learners with personal skills for emotional labour in low-level service jobs. This paper interrogates such analyses and questions whether the therapeutic role of VET really is incompatible with the traditional objectives of developing knowledge, understanding and values in work environments. Links are made between new emphases on work-based learning and the 'caring' conceptions of learning in post-school education. It is concluded that - although therapy should not dominate VET - an attention to the important values dimension of learning in the field does involve a therapeutic dimension of some kind