Suprabasin-A Review.

Among the ~22,000 human genes, very few remain that have unknown functions. One such example is suprabasin (SBSN). Originally described as a component of the cornified envelope, the function of stratified epithelia-expressed SBSN is unknown. Both the lack of knowledge about the gene role under physiological conditions and the emerging link of SBSN to various human diseases, including cancer, attract research interest. The association of SBSN expression with poor prognosis of patients suffering from oesophageal carcinoma, glioblastoma multiforme, and myelodysplastic syndromes suggests that SBSN may play a role in human tumourigenesis. Three SBSN isoforms code for the secreted proteins with putative function as signalling molecules, yet with poorly described effects. In this first review about SBSN, we summarised the current knowledge accumulated since its original description, and we discuss the potential mechanisms and roles of SBSN in both physiology and pathology.

Adaptation to robust monolayer expansion produces human pluripotent stem cells with improved viability.

The generation of human pluripotent stem cells (hPSCs) of sufficient quantity and quality remains a major challenge for biomedical application. Here we present an efficient feeder-free, high-density monolayer system in which hPSCs become SSEA-3-high and gradually more viable than their feeder-dependent counterparts without changes attributed to culture adaptation. As a consequence, monolayer hPSCs possess advantages over their counterparts in embryoid body development, teratoma formation, freezing as a single-cell suspension, and colony-forming efficiency. Importantly, this monolayer culture system is reversible, preserving the competence of hPSCs to gradually reacquire features of colony growth, if necessary. Therefore, the monolayer culture system is highly suitable for long-term, large-scale propagation of hPSCs, which is necessary in drug development and pluripotent stem cell-based therapies.

The role of the qacA gene in mediating resistance to quaternary ammonium compounds.

Conditions facilitating resistance to quaternary ammonium compounds (QACs) were investigated in Staphylococcus aureus SK982 exposed to benzalkonium chloride (BAC; a member of QACs) under various circumstances. S. aureus SK982 carrying the qacA gene encoding for resistance to QACs was grown in the presence of stable or gradually increasing concentrations of BAC, or it was exposed to this antiseptic in the exponential phase of growth. Bacteria cultivated in the highest BAC concentrations that did not retard their growth comparing to the untreated control were subjected to real-time quantitative polymerase chain reaction analysis for relative expression of the efflux genes qacA and norA. Under such conditions, S. aureus SK982 tolerated a relatively low stable concentration of BAC (1.22 mg/L) when compared with a gradually increasing antiseptic concentration (tolerance of 4.88 mg/L). However, in both cases, qacA expression was not significant. The culture exposed in the exponential phase of growth tolerated the highest concentration of BAC (9.76 mg/L) as also accompanied by significant overexpression of qacA. Expression of norA was relatively low regardless of the conditions tested. It seems that under the short-term conditions, the phase of bacterial growth is more important for the expression of BAC resistance than the capability to adapt to this antiseptic. This study provides a deeper insight into the relevance of the qac genes in conferring resistance to QACs.