Although several theories have been postulated to explain cyanobacterial blooms, their biochemical origin has not yet found. In this work, we explore the existence of bacterial communication, called quorum sensing, in Microcystis aeruginosa and Cylindrospermopsis raciborskii. Thus, application known acylhomoserine lactones cultures both cyanobacteria causes profound metabolic. At 72 h post-appl...

A graphic method of Drude equation was applied to a series of aldonic acid 1,4-lactones 1-7 to investigate possible Cotton effects below 200nm. The calculation shows three bands at 220nm, 170 nm and 130 nm to reflect the stereochemistries at C-2, C-4 and rtng conformations and vicinal OH at C-3 and C-4, respectively. The sum of the rotational contributions at 589 nm of these bands explained the...

Two racemic and two enantiomeric pairs of new δ-hydroxy-γ-lactones based on the p-menthane system were prepared from racemic and optically active cis- and trans-piperitols. The Johnson-Claisen rearrangement of the piperitols, epoxidation of the γδ-unsaturated esters, and acidic lactonization of the epoxy esters were described. The structures of the compounds were confirmed spectroscopically. Th...

Irrespective of the presence of cytotoxic acetogenins and styryl-lactones in the genus Goniothalamus, only 22 species in the genus Goniothalamus, out of 160 species (13.7%) have so far been investigated. In an effort to promote further research on the genus Goniothalamus which could represent a source of drugs for the treatment of cancers and bacterial infections, this work offers a broad analy...

To explore the feasibility of developing ligands targeted to the atypical C1 domains of protein kinase C ζ and ι, we have prepared diacylglycerol lactones substituted with hydrophilic groups on their side chains, which potentially could interact with the arginine residues that distinguish the atypical C1 domains of PKCζ and PKCι from typical C1 domains, and we have measured their binding to mut...

BACKGROUND The Australian cushion bush (Leucophyta brownii) of the Compositae family of plants has become a popular pot and container plant. The plant produces the sesquiterpene lactone allergen calocephalin. OBJECTIVES To assess the sensitizing potential of sesquiterpene lactones from cushion bush. PATIENTS/MATERIALS/METHODS Eleven Compositae-sensitive patients were patch tested with seven...

Sesquiterpene lactones display a wide variety of biological effects such as antiviral, anti-inflammatory and cytotoxic activity. In previous studies some derivatives of sesquiterpene lactones were prepared to be tested as antiviral and/or cytoxic agents. In the present report we describe the effects of seven modified sesquiterpene lactones on the proliferation of several cancer cell lines. We d...

A set of disubstituted tetracyclic lactones has been synthesized and tested for potential antitumor activity. Several of them possess a noticeable cytotoxicity against L1210 and HT-29 colon cells in vitro. Relationships between chain nature and biological properties were sought. Lactones with a pentyl or hexyl substituent at C-11 are the most active ones. The introduction of a functional group ...

The neutral and base-catalyzed hydrolysis of nine carboxylic acid esters was studied using a hybrid supermolecule-PCM approach including six explicit water molecules. The molecules studied included two linear esters, four β-lactones, two γ-lactones, and one δ-lactone: ethyl acetate and methyl formate, β-propiolactone, β-butyrolactone, β-isovalerolactone, diketene (4-methyleneoxetan-2-one), γ-bu...