Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024312 (lymphopenia)
 4,859 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Concentrations of free amino acids were measured concurrently in plasma, erythrocytes, granulocytes, and lymphocytes in umbilical cord blood, neonates, children, and adults. In each age group, the patterns of free amino acids were fairly similar in plasma and erythrocytes except for aspartic acid which was more abundant in erythrocytes. Of the amino acids in granulocytes, 71-77% was taurine; in lymphocytes taurine, aspartic acid, and glutamic acid comprised 35-44%, 18-24%, and 20-28%, respectively, of the total in all age groups. Leukocytes may contribute to the interorgan transport of amino acids to about 10% of the erythrocytes' contribution. Postnatally, the levels of glutamic acid and tyrosine in plasma; threonine plus glutamine, serine plus asparagine, and tyrosine in erythrocytes; histidine in granulocytes; and glutamic acid in lymphocytes were significantly increased (p less than 0.001); while the levels of phenylalanine and lysine in plasma; taurine in erythrocytes; valine and phenylalanine in granulocytes; and threonine plus glutamine, tyrosine, and phenylalanine in lymphocytes were significantly decreased (p less than 0.001). After the neonatal period concentrations of taurine and aspartic acid in erythrocytes, taurine and valine in granulocytes, and tyrosine and phenylalanine in lymphocytes increased gradually with age; while concentrations aspartic acid in plasma, histidine in granulocytes, and glycine in lymphocytes decreased gradually with age. The levels of glycine and valine in plasma, alanine and valine in erythrocytes, serine plus asparagine, glycine, alanine, and tyrosine in granulocytes, and aspartic acid, serine plus asparagine, and alanine in lymphocytes remained constant in all age groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Free amino acid concentrations in plasma, erythrocytes, granulocytes, and lymphocytes in umbilical cord blood, children, and adults. 673 89

Colibactin represents a structurally undefined class of bacterial genotoxin inducing DNA damage and genomic instability in mammalian cells, thus promoting tumour development and exacerbating lymphopenia in animal models. The colibactin biosynthetic gene cluster (clb) has been known for ten years and it encodes a hybrid nonribosomal peptide synthetase (NRPS)/polyketide synthase (PKS) assembly line. Nevertheless, the final chemical product(s) remain unknown. Previously, we and others reported several colibactin pathway-related metabolites including N-myristoyl-d-asparagine (1) as part of a prodrug precursor that is cleaved from the putative precolibactin to form active colibactin by the peptidase ClbP. Herein, we report two new colibactin pathway-related metabolites (2 and 3) isolated from a clbP mutant of the probiotic E. coli Nissle 1917 strain. Their structures were established by HRMS and NMR. Compound 2 shows an additional 4-aminopenatanoic acid moiety with respect to 1, while 3 is characterized by the presence of an unusual 7-methyl-4-azaspiro[2.4]hept-6-en-5-one residue. Moreover, we propose the biosynthetic pathway towards both intermediates on the basis of extensive gene inactivation and feeding experiments. The identification of 2 and 3 provides further insight into colibactin biosynthesis including the involvement and formation of a rare 1-aminocyclopropanecarboxylic acid unit. Thus, our work establishes additional steps of the pathway forming the bacterial genotoxin colibactin.
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PMID:Two more pieces of the colibactin genotoxin puzzle from Escherichia coli show incorporation of an unusual 1-aminocyclopropanecarboxylic acid moiety. 2870 87