ABSTRACT
Engineering radically altered genetic codes will allow for genomically recoded organisms that have expanded chemical capabilities and are isolated from nature. We have previously reassigned the translation function of the UAG stop codon; however, reassigning sense codons poses a greater challenge because such codons are more prevalent, and their usage regulates gene expression in ways that are difficult to predict. To assess the feasibility of radically altering the genetic code, we selected a panel of 42 highly expressed essential genes for modification. Across 80 Escherichia coli strains, we removed all instances of 13 rare codons from these genes and attempted to shuffle all remaining codons. Our results suggest that the genome-wide removal of 13 codons is feasible; however, several genome design constraints were apparent, underscoring the importance of a strategy that rapidly prototypes and tests many designs in small pieces.
Subject(s)
Codon/genetics , Escherichia coli/genetics , Genes, Essential , Genome, Bacterial/genetics , Amino Acids/genetics , Base Sequence , Escherichia coli/growth & development , Frameshift Mutation , Genes, Synthetic , Genetic Engineering , Molecular Sequence DataABSTRACT
An 11-year-old girl presented with episodic abdominal pain of 2 years' duration. CT scan of the abdomen showed a mass in the tail of the pancreas. A distal pancreatectomy was done and the tumor was excised. Macroscopic and immunohistochemical studies were compatible with a solid and papillary epithelial neoplasm. This is a rare neoplasm with a decidedly female predominance. It has a very low malignant potential with a good prognosis. Surgical removal of the tumor is usually curative.
Subject(s)
Carcinoma, Papillary , Pancreatic Neoplasms , Abdominal Pain/etiology , Carcinoma, Papillary/complications , Carcinoma, Papillary/diagnosis , Carcinoma, Papillary/surgery , Child , Chronic Disease , Female , Humans , Immunohistochemistry , Pancreatectomy , Pancreatic Neoplasms/complications , Pancreatic Neoplasms/diagnosis , Pancreatic Neoplasms/surgeryABSTRACT
The authors report on 2 children with pernicious anemia, sisters, who presented with hypermelanosis as one of the clinical manifestations. The hypermelanosis disappeared with adequate treatment of vitamin B12 deficiency. Vitamin B12 deficiency should be considered in the differential diagnosis of a child presenting with hyperpigmentation and macrocytic red cell indices.
