Heterologous expression of bacteriocin E-760 in Chlamydomonas reinhardtii and functional analysis

The use of antimicrobial peptides(AMPs)synthesized by bacteria(bacteriocins)is an alternative for combating multidrug resistant bacterial strains and their production by recombinant route is a viable option for their mass production.The bacteriocin E-760 isolated from the genus Enterococcus sp.has been shown to possess inhibitory activity against Gram-negative and Gram-positive bacteria.In this study,the expression of a chimeric protein coding for E-760 in the nucleus of C.reinhardtii was evaluated,as well as,its antibacterial activity.The synthetic gene E-760S was inserted into the genome of C.reinhardtii using Agrobacterium tumefaciens.A transgenic line was identified in TAP medium with hygromycin and also by PCR.The increment in the culture medium temperature of the transgenic strain at 35°C for 10 minutes,increased the production level of the recombinant protein from 0.14(Noninduced culture,NIC)to 0.36%(Induced culture,IC)of total soluble proteins(TSP);this was quantified by an ELISA assay.Recombinant E-760 possesses activity against Staphylococcus aureus in 0.34 U log,Streptococcus agalactiae in 0.48 U log,Enterococcus faecium in 0.36 U log,Pseudomonas aeruginosa in 2 U log and for Klebsiella pneumoniae,the activity was 0.07 U log.These results demonstrate that the nucleus transformation of C.reinhardtii can function as a stable expression platform for the production of the synthetic gene E-760 and it can potentially be used as an antibacterial agent.

The protein-protein interaction landscape of transcription factors during gynoecium development in Arabidopsis

Flowers are composed of organs whose identity is defined by the combinatorial activity of transcription factors(TFs).The interactions between MADS-box TFs and protein complex formation have been schematized in the floral quartet model of flower development.The gynoecium is the flower’s female reproductive part,crucial for fruit and seed production and,hence,for reproductive success.After the establishment of carpel identity,many tissues arise to form a mature gynoecium.TFs have been described as regulators of gynoecium development,and some interactions and complexes have been identified.However,broad knowledge about the interactions among these TFs and their participation during development remains scarce.In this study,we used a systems biology approach to understand the formation of a complex reproductive unit—as the gynoecium—by mapping binary interactions between well-characterized TFs.We analyzed almost 4500 combinations and detected more than 250 protein-protein interactions(PPIs),resulting in a process-specific interaction map.Topological analyses suggest hidden functions and novel roles for many TFs.In addition,we observed a close relationship between TFs involved in auxin and cytokinin-signaling pathways and other TFs.Furthermore,we analyzed the network by combining PPI data,expression,and genetic data,which helped us to dissect it into several dynamic spatio-temporal subnetworks related to gynoecium development processes.Finally,we generated an extended PPI network that predicts new players in gynoecium development.Taken together,all these results serve as a valuable resource for the plant community.