Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.1.53 (sialidase)
 2,694 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In order to study the effect of protein malnutrition on macrophage glycoproteins the carbohydrate composition of peritoneal macrophages from protein-deficient rats has been studied by paper chromatography and HPLC. The results show that the carbohydrate content of resident cells recovered from protein-deficient group was significantly greater than control and decreased on prolonged incubation. In the protein-deficient samples there was a significant decrease in the content of galactose, fucose and galactosamine known to be binding to specific ligands and increase in glucose and mannosamine. In both control and deficient groups, thioglycollate (TG) elicitation resulted in higher total sialic acid content. Prolonged incubation (18 hr) caused an elevation of sialic acid levels in the resident cells, whereas a drastic reduction was observed in the TG elicited cells. In the protein-fed (20%) group, the cell surface sialic acid which contributes to the negative charge of the cells, reduced significantly on culturing the TG cells but not the resident cells. In the protein-deficient group, this effect was seen in the resident cells also; in the TG cells the cell surface sialic acid was significantly low at the isolation stage suggesting that these cells had become comparatively more positively charged in vivo itself. This observed reduction could be correlated to the enhanced sialidase levels in these cells. These protein deficiency related changes in the carbohydrate composition of macrophages could lead to modification of their receptor activity and charge related functions.
 ...
PMID:Enumeration of macrophage carbohydrates in protein-deficient rats: relation to cell surface properties. 795 41

Lysosomal storage disease is one of the inborn errors of metabolism caused by a deficiency of lysosomal acid hydrolase activity. We describe here the details of screening methods for the diagnosis of this disorder. It is definitely important to perform both enzyme assay of acid hydrolases and the detection of accumulated materials in patient's tissues. Leukocytes (lymphocytes), serum or plasma, and cultured skin fibroblasts are commonly used as the enzyme source for the assay. Although most lysosomal storage diseases can be diagnosed using leukocytes as the enzyme source, enzymatic activities of beta-glucosidase and sialidase in leukocytes are sometimes normal even in patients. At present, the most reliable enzyme source is considered to be cultured skin fibroblasts. Nevertheless, we should remind that we cannot detect a deficiency of galactocerebroside beta-galactosidase activity even using fibroblasts, if we use synthetic substrate. Natural substrates should be employed for the correct diagnosis and for the study of the nature of patient's enzyme. Deficiency of the enzymatic activity in patients should be confirmed by the demonstration of accumulated materials due to the enzyme defect in patient's tissues and urine. The accumulation of mucopolysaccharides and oligosaccharides in urine is obvious in patients with mucopolysaccharidoses and mucolipidoses, respectively. In case of sphingolipidoses, rectal biopsy specimen and blood could be a target of the investigation. In final, the choice of these screening methods should be made solely based on the detailed clinical manifestation of patients.
 ...
PMID:[Screening methods for the diagnosis of lysosomal storage disease]. 857 38

Trypanosomes, protozoan parasites of medical importance, essentially rely on post-transcriptional mechanisms to regulate gene expression in insect vectors and vertebrate hosts. RNA binding proteins (RBPs) that associate to the 3'-UTR of mature mRNAs are thought to orchestrate master developmental programs for these processes to happen. Yet, the molecular mechanisms by which differentiation occurs remain largely unexplored in these human pathogens. Here, we show that ectopic inducible expression of the RBP TcUBP1 promotes the beginning of the differentiation process from non-infective epimastigotes to infective metacyclic trypomastigotes in Trypanosoma cruzi. In early-log epimastigotes TcUBP1 promoted a drop-like phenotype, which is characterized by the presence of metacyclogenesis hallmarks, namely repositioning of the kinetoplast, the expression of an infective-stage virulence factor such as trans-sialidase, increased resistance to lysis by human complement and growth arrest. Furthermore, TcUBP1-ectopic expression in non-infective late-log epimastigotes promoted full development into metacyclic trypomastigotes. TcUBP1-derived metacyclic trypomastigotes were infective in cultured cells, and developed normally into amastigotes in the cytoplasm. By artificial in vivo tethering of TcUBP1 to the 3' untranslated region of a reporter mRNA we were able to determine that translation of the reporter was reduced by 8-fold, while its mRNA abundance was not significantly compromised. Inducible ectopic expression of TcUBP1 confirmed its role as a translational repressor, revealing significant reduction in the translation rate of multiple proteins, a reduction of polysomes, and promoting the formation of mRNA granules. Expression of TcUBP1 truncated forms revealed the requirement of both N and C-terminal glutamine-rich low complexity sequences for the development of the drop-like phenotype in early-log epimastigotes. We propose that a rise in TcUBP1 levels, in synchrony with nutritional deficiency, can promote the differentiation of T. cruzi epimastigotes into infective metacyclic trypomastigotes.
 ...
PMID:Translational repression by an RNA-binding protein promotes differentiation to infective forms in Trypanosoma cruzi. 2986 62