The expression of many virulence determinants in Staphylococcus aureus including alpha-hemolysin-, protein A-, and fibronectin-binding proteins is controlled by global regulatory loci such as sar and agr. In addition to controlling target gene expression via agr (e.g. alpha-hemolysin), the sar locus can also regulate target gene transcription via agr-independent mechanisms. In particular, we ha...

BACKGROUND Chronic inflammation is known to be one of the main steps in carcinogenesis. Identification of those with chronic inflammation may help identify subjects at risk of cancer. Previous studies have reported low albumin-to-globulin ratio (AGR) to be associated with increased cancer mortality in cancer patients, but there has been no study based on healthy populations. PATIENTS AND METH...

The goal of this work was to determine whether staphylococcal enterotoxin type A gene (sea) expression is regulated by an accessory gene regulator (agr). The Tn551 insertionally inactivated agr allele of Staphylococcus aureus ISP546 was transferred to three Sea+ S. aureus strains. Each of the Agr- strains produced as much staphylococcal enterotoxin A (SEA) as its parent strain. These results su...

Repression of virulence by Staphylococcus aureus strains from different Agr groups has been demonstrated in vitro and is proposed as a means of competitive interference. Here, using the insect Manduca sexta, we show for the first time that this interference also occurs in vivo within a mixed population.

OBJECTIVE To determine how symmetric (proportionate; SGR) and asymmetric (disproportionate; AGR) growth restriction influence growth and development in preterms from birth to 4 years. METHODS This community-based cohort study of 810 children comprised 86 SGR, 61 AGR, and 663 non-growth restricted (NGR) preterms, born in 2002 and 2003. Symmetrical growth restriction was defined as a birth weig...

The synthesis of protein A in Staphylococcus aureus is regulated by global regulatory loci such as sar and agr. Phenotypic data indicate that both sar and agr suppress protein A synthesis; like agr, sar also regulates protein A production at the transcriptional level. To determine the genetic requirement of sar in protein A suppression, we transformed shuttle plasmids containing various sar fra...

We present evidence that the agr cell-to-cell communication system is present across firmicutes, including the human pathogen Clostridium perfringens. Although we find that the agr system is evolutionarily conserved and that the general functions which it regulates are similar in different species, the individual regulated genes are not the same. This suggests that the regulatory network contro...

We consider the experimental development of collaborating robots able to work within fields of crops. Specifically we investigate how AI principles can be applied to this agricultural domain and how the user should be involved in such a system. To support collaboration between agents a representation of responsibilities and dependencies is necessary. This is done by introducing groups and roles...

Staphylococcal food poisoning (SFP) is a common cause of foodborne illness worldwide, and enterotoxin D (SED) is one of the most frequent Staphylococcus aureus enterotoxins associated with it. It has been reported that the expression and formation of SED in S. aureus is regulated by the quorum sensing Agr system. In this study, the effect of agr deletion on sed expression in S. aureus grown on ...

We examined the ability of 206 clinical isolates of Staphylococcus aureus to lyse T cells and found differences between Agr groups. We found that the beta and delta hemolysins are involved and that methicillin-resistant S. aureus strains are less toxic than methicillin-susceptible S. aureus strains.