ABSTRACT
In humans, mRNA polyadenylation involves the participation of about 20 factors in four main complexes that recognize specific RNA sequences. Notably, CFIm25, CPSF73, and PAP have essential roles for poly(A) site selection, mRNA cleavage, and adenosine residues polymerization. Besides the relevance of polyadenylation for gene expression, information is scarce in intestinal protozoan parasites that threaten human health. To better understand polyadenylation in Entamoeba histolytica, Giardia lamblia, and Cryptosporidium parvum, which represent leading causes of diarrhea worldwide, genomes were screened for orthologs of human factors. Results showed that Entamoeba histolytica and C. parvum have 16 and 12 proteins out of the 19 human proteins used as queries, respectively, while G. lamblia seems to have the smallest polyadenylation machinery with only six factors. Remarkably, CPSF30, CPSF73, CstF77, PABP2, and PAP, which were found in all parasites, could represent the core polyadenylation machinery. Multiple genes were detected for several proteins in Entamoeba, while gene redundancy is lower in Giardia and Cryptosporidium. Congruently with their relevance in the polyadenylation process, CPSF73 and PAP are present in all parasites, and CFIm25 is only missing in Giardia. They conserve the functional domains and predicted folding of human proteins, suggesting they may have the same roles in polyadenylation.
Subject(s)
Cleavage And Polyadenylation Specificity Factor/genetics , Cryptosporidium parvum/genetics , Entamoeba histolytica/genetics , Giardia lamblia/genetics , Intestines/parasitology , RNA, Messenger/genetics , Cleavage And Polyadenylation Specificity Factor/chemistry , Cleavage And Polyadenylation Specificity Factor/metabolism , Cryptosporidium parvum/metabolism , Databases, Genetic , Entamoeba histolytica/metabolism , Giardia lamblia/metabolism , Humans , Models, Molecular , Open Reading Frames , Poly A/chemistry , Protein Domains , Protein Structure, Tertiary , Protozoan Proteins/chemistry , Protozoan Proteins/genetics , Protozoan Proteins/metabolism , RNA, Messenger/chemistry , RNA, Protozoan/chemistry , RNA, Protozoan/genetics , Sequence Alignment , Sequence Analysis, ProteinABSTRACT
OBJETIVE: H. pylori infection is acquired early in life, but symptoms occur mainly in adults. The mode of transmission remains unclear, but several studies have demonstrated that the microorganism may be transmitted orally. H. pylori has been detected in the oral cavity of children, and some authors have studied infection prevalence due to the importance of the bacteria in gastric and extragastric pathology. In México, little is known about H. pylori prevalence in the oral cavity of asymptomatic children, so the aims of this study were to estimate the prevalence of H. pylori in asymptomatic children and evaluate factors associated with the infection. DESING: We studied 162 asymptomatic children of 3.025±1.474 years of age from a kindergarten in México City. Oral swabs, rotating around to cheeks inside of oral cavity were obtained to determine H. pylori, using the polymerase chain reaction for 16S rRNA and glmM genes. RESULTS: We detected a 13% prevalence of H. pylori infection by PCR, and the results were confirmed by sequencing and showed a >97% identity with H. pylori. We observed increased infection with age. No association between H. pylori infection and variables such as sex, family history of gastric diseases, crowding or pets in the home were found. CONCLUSION: H. pylori infection in the oral cavity is frequent among asymptomatic children in México, which represents a risk of infection for other family members and for other children in educational facilities. Early diagnosis is essential for control of the infection and for the development of preventive strategies in childhood.
