A Bacterial Quorum Sensing Molecule Elicits a General Stress Response in .

Bacteria assess their population density through a chemical communication mechanism termed quorum sensing, in order to coordinate group behavior. Most research on quorum sensing has focused primarily on its role as an intraspecies chemical signaling mechanism that enables the regulation of certain phenotypes through targeted gene expression. However, in recent years several seminal studies have revealed important phenomena in which quorum sensing molecules appear to serve additional roles as interspecies signals that may regulate microbial ecology.

Gene deletions leading to a reduction in the number of cyclopentane rings in Sulfolobus acidocaldarius tetraether lipids.

The cell membrane of (hyper)thermophilic archaea, including the thermoacidophile Sulfolobus acidocaldarius, incorporates dibiphytanylglycerol tetraether lipids. The hydrophobic cores of such tetraether lipids can include up to eight cyclopentane rings. Presently, nothing is known of the biosynthesis of these rings.

N-glycosylation in the thermoacidophilic archaeon Sulfolobus acidocaldarius involves a short dolichol pyrophosphate carrier.

N-glycosylation is a post-translational modification that occurs across evolution. In the thermoacidophilic archaea Sulfolobus acidocaldarius, glycoproteins are modified by an N-linked tribranched hexasaccharide reminiscent of the N-glycans assembled in Eukarya. Previously, hexose-bearing dolichol phosphate was detected in a S.

Tailor-made LasR agonists modulate quorum sensing in Pseudomonas aeruginosa.

The primary quorum sensing system in the opportunistic pathogen Pseudomonas aeruginosa is regulated through the synthesis and secretion of N-3-oxo-dodecanoyl-L-homoserine lactone (C12) which binds the transcriptional activator LasR. In this study we report the design, synthesis and biological evaluation of new analogs of C12. Analysis of the autoinducer binding site cavity of LasR revealed a positively charged cavity near the center of bound C12.

Species selective diazirine positioning in tag-free photoactive quorum sensing probes.

The synthesis and comparison of activities of 'tag-free' probes with diazirines at various positions are described. Remarkable differences in their effects on P. aeruginosa and on human bronchial epithelial cells were observed, supporting the efforts to isolate and identify receptors for N-acyl homoserine lactones.

Manipulation of host behavior by parasitic insects and insect parasites.

Parasites often alter the behavior of their hosts in ways that are ultimately beneficial to the parasite or its offspring. Although the alteration of host behavior by parasites is a widespread phenomenon, the underlying neuronal mechanisms are only beginning to be understood. Here, we focus on recent advances in the study of behavioral manipulation via modulation of the host central nervous system.

Effects of NO/cGMP signaling on behavioral changes in subordinate male crickets, Gryllus bimaculatus.

After a loss against an opponent, the aggressiveness of a male cricket is significantly reduced for up to 30 minutes. This depression of aggressiveness is an important factor in the establishment and maintenance of dominance between individuals. In the present study, we investigated the functional roles of nitric oxide (NO) signaling in the depression of aggressiveness in subordinate male crickets.

Effects of previous experience on the agonistic behaviour of male crickets, Gryllus bimaculatus.

Male solitary animals frequently enter aggressive interactions with conspecific individuals to protect their territory or to gain access to females. After an agonistic encounter, the loser (subordinate individual) changes its behaviour from aggression to avoidance. We investigated agonistic interactions between pairs of male crickets to understand how dominance is established and maintained.

Experience-based agonistic behavior in female crickets, Gryllus bimaculatus.

Fighting behavior in male crickets is already well described, and some of the mechanisms underlying aggression and aggressive motivation have already been revealed. Much less is known about female/female interactions. Here, we report that adult female crickets that had been isolated for several days readily entered into agonistic interactions with conspecific individuals.

An evolutionarily conserved mechanism for sensitization of soluble guanylyl cyclase reveals extensive nitric oxide-mediated upregulation of cyclic GMP in insect brain.

Soluble guanylyl cyclase (SGC) is the main receptor for the gaseous signalling molecule nitric oxide (NO) in vertebrates and invertebrates. Recently, a novel class of drugs that regulate mammalian SGC by NO-independent allosteric mechanisms has been identified [e.g.