Kanamycin belongs to the aminoglycoside class of bacteriostatic antibiotics that inhibits protein synthesis. Previous studies have shown that treatment with sublethal levels of kanamycin causes the extracellular polysaccharide capsule in E. coli B23 to increase in size, and potentially confers the bacterium with kanamycin resistance. This study attempted to confirm this by establishing that inc...

Dynamic phosphorylation and dephosphorylation of the hepadnavirus core protein C-terminal domain (CTD) are required for multiple steps of the viral life cycle. It remains unknown how the CTD phosphorylation state may modulate core protein functions but phosphorylation state-dependent viral or host interactions may play a role. In an attempt to identify host factors that may interact differentia...

The human pt20 nucleolar protein is a cell cycle-related protein that peaks during the S phase and has been shown to be associated with a beaded fibrillar structure. To study domains responsible for the nucleolar localization of protein p120, initially deletion mutants were made that defined sequences containing the localization signals; then, fusion genes that were composed of segments of the ...

Previous studies have shown that pre-treatment of Escherichia coli B23 with subinhibitory concentrations of aminoglycosides leads to a subsequent increase in the level of capsular polysaccharide, as well as an increased resistance to streptomycin. Using capsular polysaccharide synthesis pathway mutants, we investigated the correlation between the level of capsular polysaccharide and streptomyci...

The nucleolus is a subnuclear compartment and the site of ribosome biogenesis. Previous studies have implicated protein ubiquitylation in nucleolar activity. Here we show that USP36, a deubiquitylating enzyme of unknown function, regulates nucleolar activity in mammalian cells. USP36 localized to nucleoli via the C-terminal region, which contains basic amino acid stretches. Dominant-negative in...

Streptomycin, an aminoglycoside, binds to and modifies prokaryotic ribosomes leading to a decrease in protein synthesis and the production of mistranslated proteins. Previous studies reported that Escherichia coli B23, under sub-lethal concentrations of streptomycin, exhibited an increase in capsule polysaccharide (CPS). The mechanism through which this increase in CPS occurs was unknown. In th...

17α-Methyltestosterone (MT) is widely used in fish hatcheries of many countries to produce male monosex populations. Its genotoxic risk to fish species is not well known and studies in other in vivo models are still inconclusive. MT was tested for genotoxicity in the fish species Oreochromis niloticus (tilapia), a target species, and Astyanax bimaculatus (lambari), a native non-target species. ...

When the nucleolus disassembles during open mitosis, many nucleolar proteins and RNAs associate with chromosomes, establishing a perichromosomal compartment coating the chromosome periphery. At present nothing is known about the function of this poorly characterised compartment. In this study, we report that the nucleolar protein Ki-67 is required for the assembly of the perichromosomal compart...