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Video game addiction in children and teenagers in Taiwan is associated with levels of animosity, social skills, and academic achievement. This study suggests that video game addiction can be statistically predicted on measures of hostility, and a group with high video game addiction has more hostility than others. Both gender and video game addiction are negatively associated with academic achievement. Family function, sensation seeking, gender, and boredom have statistically positive relationships with levels of social skills. Current models of video game addiction do not seem to fit the findings of this study.

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bReversible lysine acetylation (RLA) is used by cells of all domains of life to modulate protein function. To date, bacterial acetylation/deacetylation systems have been studied in a few bacteria (e.g., Salmonella enterica, Bacillus subtilis, Escherichia coli, Erwinia amylovora, Mycobacterium tuberculosis, and Geobacillus kaustophilus), but little is known about RLA in antibiotic-producing actinomycetes. Here, we identify the Gcn5-like protein acetyltransferase AcuA of Saccharopolyspora erythraea (SacAcuA, SACE_5148) as the enzyme responsible for the acetylation of the AMP-forming acetyl coenzyme A synthetase (SacAcsA, SACE_2375). Acetylated SacAcsA was deacetylated by a sirtuin-type NAD ؉ -dependent consuming deacetylase (SacSrtN, SACE_3798). In vitro acetylation/deacetylation of SacAcsA enzyme was studied by Western blotting, and acetylation of lysine residues Lys 237 , Lys 380 , Lys 611 , and Lys 628 was confirmed by mass spectrometry. In a strain devoid of SacAcuA, none of the above-mentioned Lys residues of SacAcsA was acetylated. To our knowledge, the ability of SacAcuA to acetylate multiple Lys residues is unique among AcuA-type acetyltransferases. Results from site-specific mutagenesis experiments showed that the activity of SacAcsA was controlled by lysine acetylation. Lastly, immunoprecipitation data showed that in vivo acetylation of SacAcsA was influenced by glucose and acetate availability. These results suggested that reversible acetylation may also be a conserved regulatory posttranslational modification strategy in antibiotic-producing actinomycetes. R eversible lysine acetylation (RLA) of proteins is now recognized as a ubiquitous and conserved posttranslational modification in a variety of organisms (1-4). Recent studies have identified over 2,000 acetylated proteins, ranging from transcriptional factors and ribosomal proteins to metabolic enzymes related to glycolysis, gluconeogenesis, the tricarboxylic acid (TCA) cycle, and fatty acid and nitrogen metabolisms. This kind of posttranslational modification (PTM) has emerged as an important metabolic regulatory mechanism in bacteria since the discovery of acetylation of the Salmonella enterica acetyl coenzyme A (Ac-CoA) synthetase in 2002 (5). In the last decade, lysine acetylation of proteins has been reported in other microorganisms, including Escherichia coli, Bacillus subtilis, Streptomyces lividans, Mycobacterium tuberculosis, Erwinia amylovora, Thermus thermophilus, and Geobacillus kaustophilus (6-9).RLA has been found to modulate protein synthesis, central metabolism, and detoxification metabolism. Yu et al. identified 85 acetylated proteins in E. coli, of which 24 (28%) are involved in protein biosynthesis and 16 (19%) are involved in carbohydrate metabolism (10). Zhang et al. also reported that more than 70% of the 91 acetylated proteins in E. coli are metabolic enzymes (53%) and translation regulators (22%) (11). More recently, Wang et al. identified 235 peptides containing acetylated lysines in a total of 191 proteins in Salmonella ent...

Lysine acetylation is a dynamic, reversible posttranslational modification that is known to play an important role in regulating the activity of many key enzymes in bacteria. Acetylproteome studies have been performed on some bacteria. However, until now, there have been no data on Actinomycetes, which are the major producers of therapeutic antibiotics. In this study, we investigated the first acetylproteome of the erythromycin-producing actinomycete Saccharopolyspora erythraea using a high-resolution mass spectrometry-based proteomics approach. Using immune-affinity isolation of acetyl-peptides with an anti-acetyllysine antibody followed by nano ultra performance liquid chromatography tandem mass spectroscopy (nanoUPLC-MS/MS) analysis, we identified 664 unique lysine-acetylated sites on 363 proteins. Acetylated proteins are involved in many biological processes such as protein synthesis, glycolysis/gluconeogenesis, citric acid (TCA) cycle, fatty acid metabolism, secondary metabolism, and the feeder metabolic pathways of erythromycin synthesis. We characterized the acetylproteome and analyzed in detail the impact of acetylation on diverse cellular functions according to Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Four motif sequences surrounding the acetylation sites (K(AC)H, K(AC)Y, K(AC)XXXXR, and K(AC)XXXXK) were found in the S. erythraea acetylproteome. These findings suggest that abundant lysine acetylation occurs in Actinomycetes, expand our current knowledge of the bacterial acetylproteome, and provide insight into the regulatory function of acetylation in primary and secondary metabolism.