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The kidneys
Published in Martin Andrew Crook, Clinical Biochemistry & Metabolic Medicine, 2013
Other rare stones may consist of dihydroxyadenine (due to adenine phosphoribosyltransferase deficiency) or poorly calcified mucoproteinaceous material associated with chronically infected kidneys (matrix stone). Some stones may be factitious, as sometimes found in patients with Munchausen’s syndrome, who may add ‘stones’ to their urine.
Current understanding of Lesch-Nyhan disease and potential therapeutic targets
Published in Expert Opinion on Orphan Drugs, 2019
Human HPRT is encoded by the HPRT1 gene located on the long arm of the X chromosome [21] and HPRT deficiency is inherited as a recessive X-linked trait. Thus, males are generally affected and women are generally asymptomatic carriers. Several women with LND due to a variety of molecular mechanisms have been described in the literature [22–26]. HPRT1 mutations, accounting for HPRT deficiency, are very heterogeneous in type and localization [27-30]. The diagnosis of HPRT deficiency must be supported by clinical, biochemical, enzymatic and molecular data. Hyperuricemia with hyperuricosuria is the biochemical hallmark that prompts an enzymatic diagnosis [29]. Patients present low or undetectable HPRT activity in hemolysates, with increased adenine phosphoribosyltransferase (APRT) activity. To better characterize the HPRT deficiency, in order to find a possible residual activity, enzyme activity can be measured in intact cells (erythrocytes or fibroblasts) [4,10,30]. Although LND variants are designated as partial HPRT deficiency, only HRH patients exhibit a residual HPRT activity in hemolysates, while it is extremely unusual in HND patients [30]. Some residual HPRT activity has been described in fibroblasts from patients with HND [3].
Emerging therapeutic targets for treatment of leishmaniasis
Published in Expert Opinion on Therapeutic Targets, 2018
Recently, nicotinamidase, enzyme involved in assimilation of nicotinamide, nicotinic acid, and nicotinamide riboside, has been used to synthesize NAD+ by salvage pathway. It constitutes a key component of parasite development and virulence; add-back and mutational studies have attracted the scientific community for designing novel inhibitors and utilize this molecule as a therapeutic target [326]. Leishmania utilizes a purine pathway from the mammalian system using different nucleoside transporters. Phosphoribosyltransferases constitute a key component of the purine salvage pathway including three main enzymes: hypoxanthine-guanine phosphoribosyltransferase, xanthine phosphoribosyltransferase, and adenine phosphoribosyltransferase [327,328]. Leishmania has several enzymes for break down of host nucleosides, nucleotide, and nucleic acid before incorporation into its purine pools. Cloning, expression, and immunolocalization have led to characterization of several nucleoside hydrolases [329–331], several nucleases/nucleotidases that generates free nucleosides [332,333] thereby making the purine accessible for translocation through transporters into the parasite.
Proteomic response in Streptococcus gordonii DL1 biofilm cells during attachment to salivary MUC5B
Published in Journal of Oral Microbiology, 2021
Carolina Robertsson, Gunnel Svensäter, Zoltan Blum, Magnus E Jakobsson, Claes Wickström
Six novel biofilm cell proteins common to all biofilm cultures but absent in planktonic culture (PurD, PurN, PurK, AbpB, MsmF and one uncharacterized protein, SGO_0965) were identified. PurD, PurN and PurK are all involved in the de novo purine nucleobase biosynthesis pathway (PBP) [27]. PurE (UniProt accession number A8AZX8) and PurF (A8AU98), involved in the same pathway, were present in all biofilm culture triplicates but absent from two of the three planktonic triplicates. The remaining five member proteins of this pathway (PurA-C, PurH, PurM, UniProt accession numbers A8AZM9, A8AZX3, A8AU96, A8AUA2 and A8AU99) were present in all cultures with no significant difference in abundance. Purine is essential for all living organisms due to its role in a variety of cellular functions [32], and as demonstrated in Streptococcus agalactiae [33], growth is inhibited if the bacteria cannot either de novo synthesize or salvage purine from the environment. Four proteins were annotated with the GO terms for the biological processes related to purine salvage (GO:0043101, GO:0043096, GO:0006166 or GO:0032261) for S. gordonii DL1 in UniProt; adenylate kinase (Adk, A8AZK4), xanthine phosphoribosyltransferase (Xpt, A8AXD5), hypoxanthine phosphoribosyltransferase (Hpt, A8AZZ9) and adenine phosphoribosyltransferase (Apt, A8AWY0) [27]. All these purine salvage proteins were present in planktonic and biofilm cultures without any significant differences in abundance. The presence of the PBP Pur-proteins as well as purine salvage pathway proteins in biofilm cultures suggests that cells in this growth condition perform both de novo purine biosynthesis as well as employ salvage pathways for scavenging purine from the environment, while the absence of many of the Pur-proteins in planktonic cells suggest that suspended cells may primarily rely on salvage pathways.