Search results

Sort By:

Limit search:

Enzymatic degradation of acyl-homoserine lactones and its possible use in biocontrol and suppression of infection development

100%

Czajkowski R., Jafra S.

Biotechnologia

2006

issue 2

49-64

A large number of different bacteria populations control diverse metabolic processes through production and distribution of specific signal molecules, which concentration in the environment depends on bacteria cell density and rise when bacteria population expands. This strategy is known as quorum sensing (QS), and was first described in Gram-negative, marine bacterium Vibrio fischeri. QS, a mechanism of gene expression regulation dependent on bacterial cell density, is widely distributed in Gram-negative bacteria; and controls different physiological processes such as production of virulence factors, conjugal plasmid transfer, antibiotic production, replication, swarming or luminescence. QS functions via signal molecules: in Gram-negative bacteria, the signal molecules belong to the acyl-homoserine lactones (AHLs). It was found that many bacteria possess the ability to interfere in QS (strategy known as quorum quenching- QQ) by enzymatic degradation of AHLs. Till now, two classes of enzymes able to degrade AHLs have been described: AHL-lactonases and AHL-acylases. AHL-lactonases hydrolyze the ester bond in the lactone ring of AHLs. AHL-acylases hydrolyze the amide bond between the acyl side chain and the lactone ring in AHLs. Both reactions lead to the inhibition of signal transfer in QS as degradation products cannot act as signal molecules. QS plays a major role in pathogenesis and as such is deeply studied as a useful target for modern, antimicrobial therapy in human medicine and veterinary, as well as in biocontrol of plant diseases.

Sphingosine modulates Ca2+ signals via phospholipase C dependent pathway in glioma C6 cells

81%

Czajkowski R., Sabala P., Baranska J.

Acta Neurobiologiae Experimentalis

1997

vol. 57

issue 4

353

Sphingosine at the concentration of 100 muM is depleting ER calcium stores, causing a rise in intracellular calcium ranging from 50 to 100 nM. It also decreases Ca2+ response caused by 100 nM thapsigargin. Preincubation with 10 mM neomycin, a high affinity ligand for PIP2, which inhibits PLC and PLD activitity in brain, partially eliminates the effect of sphingosine on thapsigargin elicited Ca2+ signal. This effect is not observed after preincubation with 150 mM ethanol, which acts as a substrate for PLD, blocking its normal activity by production of phosphatidylethanol instead phosphatidic acid. These results suggest that sphingosine may act on intracellular Ca2+ stores and stimulate Ca2+ mobilization via process mediated rather by PLC than by PLD activation.ion.

Refine search results

1 Acta Neurobiologiae Experimentalis

1 Biotechnologia

1 2006

1 1997

2 Czajkowski R.

1 Baranska J.

1 Jafra S.

1 Sabala P.

Search results

Enzymatic degradation of acyl-homoserine lactones and its possible use in biocontrol and suppression of infection development

Sphingosine modulates Ca2+ signals via phospholipase C dependent pathway in glioma C6 cells