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Project description:Bacteria-host interactions are dynamic processes, and understanding transcriptional responses that directly or indirectly regulate the expression of genes involved in initial infection stages would illuminate the molecular events that result in host colonization. We used oligonucleotide microarrays to monitor (in vitro) differential gene expression in group A streptococci during pharyngeal cell adherence, the first overt infection stage. We present neighbor clustering, a new computational method for further analyzing bacterial microarray data that combines two informative characteristics of bacterial genes that share common function or regulation: (1) similar gene expression profiles (i.e., co-expression); and (2) physical proximity of genes on the chromosome. This method identifies statistically significant clusters of co-expressed gene neighbors that potentially share common function or regulation by coupling statistically analyzed gene expression profiles with the chromosomal position of genes. We applied this method to our own data and to those of others, and we show that it identified a greater number of differentially expressed genes, facilitating the reconstruction of more multimeric proteins and complete metabolic pathways than would have been possible without its application. We assessed the biological significance of two identified genes by assaying deletion mutants for adherence in vitro and show that neighbor clustering indeed provides biologically relevant data. Neighbor clustering provides a more comprehensive view of the molecular responses of streptococci during pharyngeal cell adherence.
| S-EPMC1913099 | biostudies-literature
Project description:BackgroundThe discovery of genetic mutations in children with inherited syndromes of intrahepatic cholestasis allows for diagnostic specificity despite similar clinical phenotypes. Here, we aimed to determine whether mutation screening of target genes could assign a molecular diagnosis in children with idiopathic cholestasis.Patients and methodsDNA samples were obtained from 51 subjects with cholestasis of undefined etiology and surveyed for mutations in the genes SERPINA1, JAG1, ATP8B1, ABCB11, and ABCB4 by a high-throughput gene chip. Then, the sequence readouts for all 5 genes were analyzed for mutations and correlated with clinical phenotypes. Healthy subjects served as controls.ResultsSequence analysis of the genes identified 14 (or 27%) subjects with missense, nonsense, deletion, and splice site variants associated with disease phenotypes based on the type of mutation and/or biallelic involvement in the JAG1, ATP8B1, ABCB11, or ABCB4 genes. These patients had no syndromic features and could not be differentiated by biochemical markers or histopathology. Among the remaining subjects, 10 (or ∼20%) had sequence variants in ATP8B1 or ABCB11 that involved only 1 allele, 8 had variants not likely to be associated with disease phenotypes, and 19 had no variants that changed amino acid composition.ConclusionsGene sequence analysis assigned a molecular diagnosis in 27% of subjects with idiopathic cholestasis based on the presence of variants likely to cause disease phenotypes.
| S-EPMC4090691 | biostudies-literature
Project description:Recent studies support the existence of oogonial stem cells (OSCs) in the ovarian cortex of different mammals, including women.These cells are characterized by small size, membrane expression of DEAD(Asp-Glu-Ala-Asp)-box polypeptide-4 (Ddx4), and stemness properties (such as self-renewal and clonal expansion) as well as the ability to differentiate in vitro into oocyte-like cells. However, the discovery of OSCs contrasts with the popular theory that there is a numerically defined oocyte pool for female fertility which undergoes exhaustion with menopause. Indeed, in the ovarian cortex of postmenopausal women OSCs have been detected that possess both viability and capability to differentiate into oocytes, which is similar to those observed in younger patients. The pathophysiological role of this cell population in aged women is still debated since OSCs, under appropriate stimuli, differentiate into somatic cells, and the occurrence of Ddx4+ cells in ovarian tumor samples also suggests their potential involvement in carcinogenesis. Although further investigation into these observations is needed to clarify OSC function in ovary physiology, clinical investigators and researchers studying female infertility are presently focusing on OSCs as a novel opportunity to restore ovarian reserve in both young women undergoing early ovarian failure and cancer survivors experiencing iatrogenic menopause.
| S-EPMC6678385 | biostudies-literature
Project description:Smooth muscle neoplasms with atypical proliferative behaviour, but without clear histopathological malignancy represent a diagnostic and therapeutic challenge, as distinction from a sarcoma can be difficult and no guaranteed treatment recommendations are available due to the rarity of these changes. In the event of uncertain primary histology, even metastases cannot be assessed as malignancy criteria, but may contribute to the clarification of the histology. Similarities with other smooth muscle proliferations, such as lymphangioleiomyomatosis, are striking. The diagnostic difficulties and treatment options are explained based on the example of a 59-year-old patient, in whom a retroperitoneal mass and pulmonary lesion of such a tumour occurred 4 years after a hysterectomy. Even though the genesis and histological diagnostics have not been conclusively clarified, slow growth and a low recurrence rate for post-menopausal patients allow for a wait-and-see approach, whereby the option for anti-hormonal treatment exists in the event of positive evidence of hormone receptors.
| S-EPMC4024611 | biostudies-literature