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Escherichia coli transformation is an essential step in many molecular biology experiments. Despite earlier advances in the field, many studies including shotgun cloning still require more efficient transformation protocols. Chemical transformation has been the most popular method, in which competent cells are transformed following a brief period of heat shock. Here, we report a novel protocol with higher efficiency, in which competent E. coli cells (treated with CaCl2 ) grown in media containing glycerol experience a gentle vibration. Three E. coli strains DH5α, Jm107 and BL21 (DE3) and three plasmids pGEM-T, pET-28a and pCAMBIA with different sizes (3000, 5369 and 8428 bp, respectively) were used to test the protocol. The results indicated a significant increase in number of transformed colonies compared with heat-shock method. Our findings also demonstrated the favourable impacts of glycerol on transformation of E. coli.

This study reports a novel carrier based on blends of carboxymethyl cellulose (CMC) and k-carrageenan (k-Carr) for probiotic colon delivery. Lactobacillus plantarum ATCC:13643 (L. plantarum) cells were encapsulated in CMC/k-Carr blends by extrusion method. k-Carrageenan was used as a coating agent to improve encapsulation of L. plantarum cells in carboxymethyl cellulose biopolymer. K-Carrageenan and carboxymethyl cellulose were ionically cross-linked with K+ and Ca2+ ions, respectively. Optical and scanning electron microscopy obviously showed the random distribution of L. plantarum cells throughout the blend network. The viability of encapsulated cells in simulated gastric fluid (SGF) and bile salt solution were conducted. Results indicated that CMC/k-Carr blends could successfully protect L. plantarum cells against adverse conditions of the gastro-intestinal tract and bile salt solution. After sequential exposure to SGF for 2h almost complete death of free cells was observed. However, the number of surviving cells was 5.20 and 7.30 Log CFU/g for uncoated free CMC and CMC/k-Carr blends, respectively. Cumulatively the results of this research offer a suitable media to potentially deliver probiotics to colon site.

Despite worldwide vaccination against devastating diseases for decades, millions of children in remote and impoverished regions of the globe die every year from vaccine-preventable infectious diseases. The reasons for incomplete coverage of vaccination programs are based in part on the relatively high costs of conventional vaccinations, including mass production, refrigeration, transportation, and training as well as funding personnel for their administration. Plant-based edible vaccines (PEVs) have been introduced as a revolutionary cost-effective vaccination modality. However, they suffer from major deficiencies that have restricted their application to bench-scale. This article discusses the deficiencies of PEVs and also provides concise overview on the health-promoting, biological and biotechnological features of spirulina (Arthrospira). In short, we envision that spirulina could be considered as a potential alternative biofactory system to the plants toward the production of edible vaccines in high-yield with low-costs that other hosts cannot yet offer.