Protein trans-splicing by the naturally split intein of the gene dnaE from Nostoc punctiforme (Npu DnaE) was demonstrated here with non-native exteins in Escherichia coli. Npu DnaE possesses robust trans-splicing activity with an efficiency of >98%, which is superior to that of the DnaE intein from Synechocystis sp. strain PCC6803 (Ssp DnaE). Both the N-and C-terminal parts of the split Npu DnaE intein can be substituted with the corresponding fragment of Ssp DnaE without loss of trans-splicing activity. Protein splicing with the Npu DnaE N is also more tolerant of amino acid substitutions in the C-terminal extein sequence.

The purpose of this overview is to make the case for the establishment and publication of standards for home enteral nutrition (HEN) therapy in adult patients who require a long-term alternative to oral feeding. Overviews can provide a broad and often comprehensive summation of a topic area and, as such, have value for those coming to a subject for the first time. It will provide a broad summation, background and rationale, review specific considerations unique to HEN (tubes, products and supplies) and we describe a recent audit of seven HEN programs which highlights tube and process related challenges. Based on the overview of the literature and our experience with the audit we propose a way forward for best home enteral nutrition care.

Trace elements (TEs) are an essential component of parenteral nutrition (PN). Over the last few decades, there has been increased experience with PN, and with this knowledge more information about the management of trace elements has become available. There is increasing awareness of the effects of deficiencies and toxicities of certain trace elements. Despite this heightened awareness, much is still unknown in terms of trace element monitoring, the accuracy of different assays, and current TE contamination of solutions. The supplementation of TEs is a complex and important part of the PN prescription. Understanding the role of different disease states and the need for reduced or increased doses is essential. Given the heterogeneity of the PN patients, supplementation should be individualized.

Removal of Mn as an additive in HPN solutions resulted in resolution of MRI abnormalities in most patients. Over 5 years, all patients except for 1 maintained normal blood Mn levels. Therefore, Mn levels should be monitored and supplementation be individualized.