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We synthesized a new inhibitor of tubulin polymerization, the pyrrole (1-(7H-pyrrolo[2,3- d]pyrimidin-4-yl)-1H-pyrrol-3-yl)(3,4,5-trimethoxy-phenyl)methanone 6 (RS6077). Compound 6 inhibited the growth of multiple cancer cell lines, with IC

We synthesized new aroyl diheterocyclic pyrrole (ARDHEP)

The design of compounds able to combine the selective inhibition of cyclooxygenase-2 (COX-2) with the release of nitric oxide (NO) is a promising strategy to achieve potent anti-inflammatory agents endowed with an overall safer profile and reduced toxicity upon gastrointestinal and cardiovascular systems. With the aim of generating novel and selective COX-2 inhibiting NO-donors (CINOD) and encouraged by the promising results obtained with our nitrooxy- and hydroxyethyl ethers 11 and 12 reported in previous works, we shifted our attention on the synthesis of isosteric thioanalogs nitrooxy- and hydroxy ethyl sulfides 13a-c and 14a-c, respectively, along with their oxidation products nitrooxy- and hydroxyethyl sulfoxides 15a-c and 16a-c, respectively, also referred to as thio-CINOD. Preliminary data and metabolic analysis highlighted how the isosteric substitution of the ethereal oxygen atom of 11a-c with sulfur in compounds 13a-c, independently from the presence and the number of fluorine atoms in N

Cystic fibrosis transmembrane conductance regulator (CFTR) modulators improve clinical outcomes with variable efficacy in patients with cystic fibrosis (CF). However, changes produced by bacterial persistence and adaptation in addition to antibiotic regimens could influence CFTR modulator efficacy and vice versa and hence clinical outcomes. We first evaluated the effects of ivacaftor (IVA), lumacaftor (LUM), tezacaftor, elexacaftor and elexacaftor/tezacaftor/ivacaftor (ETI), alone or combined with antibiotics, on sequential Staphylococcus aureus and Pseudomonas aeruginosa CF isolates. IVA and ETI showed the most potent direct antimicrobial activity against S. aureus, while P. aeruginosa was not affected. Additive effects or synergies were observed between the CFTR modulators and antibiotics against both S. aureus and P. aeruginosa, independently of the stage of colonization. IVA and LUM were the most effective in potentiating antibiotic activity against S. aureus, while IVA and ETI enhanced mainly polymyxins activity against P. aeruginosa. Next, we evaluated the effect of P. aeruginosa pneumonia on the pharmacokinetics of IVA in mice. The time-concentration curves of IVA and its metabolites in plasma, lung and epithelial lining fluid were influenced by P. aeruginosa infection. The area under the concentration-time curve showed that airway exposure to IVA was greater in infected than non-infected mice. These results suggest that CFTR modulators can have direct antimicrobial properties and/or enhance antibiotic activity against S. aureus and P. aeruginosa. Furthermore, bacterial infection impacts the IVA concentration and airway exposure, potentially affecting its efficacy. Our findings suggest optimizing host- and pathogen-directed drug regimens to improve efficacy for personalized treatment.

Introduction: Pancreatic cancer (PC) is one of the most lethal tumor worldwide, with no prognosis improvement over the past 20-years. The silent progressive nature of this neoplasia hampers the early diagnosis, and the surgical resection of the tumor, thus chemotherapy remains the only available therapeutic option. Sigma receptors (SRs) are a class of receptors proposed as new cancer therapeutic targets due to their over-expression in tumor cells and their involvement in cancer biology. The main localization of these receptors strongly suggests their potential role in ER unfolded protein response (ER-UPR), a condition frequently occurring in several pathological settings, including cancer. Our group has recently identified RC-106, a novel pan-SR modulator with good in vitro antiproliferative activities toward a panel of different cancer cell lines. In the present study, we investigated the in vitro properties and pharmacological profile of RC-106 in PC cell lines with the aim to identify a potential lead candidate for the treatment of this tumor. Methods: Pancreatic cancer cell lines Panc-1, Capan-1, and Capan-2 have been used in all experiments. S1R and TMEM97/S2R expression in PC cell lines was quantified by Real-Time qRT-PCR and Western Blot experiments. MTS assay was used to assess the antiproliferative effect of RC-106. The apoptotic properties of RC-106 was evaluated by TUNEL and caspase activation assays. GRP78/BiP, ATF4, and CHOP was quantified to evaluate ER-UPR. Proteasome activity was investigated by a specific fluorescent-based assay. Scratch wound healing assay was used to asses RC-106 effect on cell migration. In addition, we delineated the in vivo pharmacokinetic profile and pancreas distribution of RC-106 in male CD-1 mice. Results: Panc-1, Capan-1, and Capan-2 express both SRs. RC-106 exerts an antiproliferative and pro-apoptotic effect in all examined cell lines. Cells exposure to RC-106 induces the increase of the expression of ER-UPR related proteins, and the inhibition of proteasome activity. Moreover, RC-106 is able to decrease PC cell lines motility. The in vivo results show that RC-106 is more concentrated in pancreas than plasma. Conclusion: Overall, our data evidenced that the pan-SR modulator RC-106 is an optimal candidate for in vivo studies in animal models of PC.

Objectives Parkinson's disease (PD) is a neurodegenerative disease characterized by loss of dopaminergic neurons in the Substantia Nigra pars compacta (SNc). The proinflammatory response can occur early in the disease, contributing to nigrostriatal degeneration. Identification of the new molecules, which are able to slow down the degenerative process associated with PD, represents one of the main interests. Recently, natural polyphenols, especially lignans, have raised attention for their anti-inflammatory, antioxidant, and estrogenic activity at a peripheral level. The aim of this study was to evaluate the central effects of chronic treatment with lignan 7-hydroxymatairesinol (HMR/lignan) on neurodegenerative, neuroinflammatory processes and motor deficits induced by a unilateral intrastriatal injection of 6-hydroxydopamine (6-OHDA) in rats to evaluate the potential neuroprotective properties of this compound. Methods Sprague-Dawley male rats underwent lignan (10 mg/kg) or vehicle treatment (oral) for 4 wk starting from the day of 6-OHDA injection. The degree of nigrostriatal damage was evaluated by immunohistochemistry. Moreover, we performed a quantitative and qualitative assessment of neuroinflammatory process, including phenotypic polarization of microglia and astrocytes. The motor performance was assessed by behavioral tests. Results We demonstrated that chronic treatment with HMR/lignan was able to slow down the progression of degeneration of striatal dopaminergic terminals in a rat model of PD, with a consequent improvement in motor performance. Nevertheless, the anti-inflammatory effect of HMR/lignan observed in SNc was not sufficient to protect dopaminergic cells bodies. Conclusion These results suggest intriguing properties of HMR/lignan at neuroprotective and symptomatic levels in the context of PD.

The Global CRO Council for Bioanalysis (GCC) was formed in an effort to bring together many senior-level representatives of CROs to openly discuss bioanalysis and the regulatory challenges, many of them unique to the outsourcing industry. CROs are unique in that they work with many different pharmaceutical companies and agencies, which results in a distinctive and comprehensive perspective on scientific approaches in relation to regulatory requirements. More information on GCC unique structure can be found in the publication titled ‘Formation of a Global Contract Research Organization Council for Bioanalysis’ [1] and its scientific activities have been subsequently published in articles and White Papers [2–6].

Senior representatives of GCC member companies have thoroughly evaluated and discussed the new European Medicines Agency (EMA; July 2011 [1]) Guideline on Bioanalytical Method Validation (BMV), during the 4th GCC (23 October 2011, Washington DC, USA) and 5th GCC (14 November 2011, Barcelona, Spain) Closed Forums. These North American and European events provided a unique opportunity for CRO leaders to openly share opinions and perspectives and to agree on unified bioanalytical recommendations specifically in relation with the new EMA guideline. The Global CRO Council for Bioanalysis (GCC) [101] is a global independent group of many Contract Research Organization (CRO) leaders. The GCC was formed in September 2010 to meet regularly and discuss bioanalytical issues and regulatory challenges, many of them unique to the outsourcing industry. The outcome of the discussions held as part of these GCC closed forum meetings are shared with the global bioanalytical community via pertinent publications [2–6] and appropriate conference presentations. Prior to the issue of this new guideline, the November 2009 Draft EMA Guideline on BMV defined the proposed guideline and criteria of the EMA on validation of bioanalytical methods and their application in the analysis of study samples from animal and human studies [7]. The EMA Guideline states that the validation of the bioanalytical methods to be used on non-clinical pharmacotoxicological studies to be submitted in a marketing authorization application should be performed following the Recommendations on the interpretation of the new European Medicines Agency Guideline on Bioanalytical Method Validation by Global CRO Council for Bioanalysis (GCC)

Interleukin-8 and growth related oncogene-α-chemokines (formerly CXCL8 and CXCL1, respectively) mediate chemotaxis of neutrophils to inflammatory sites via interactions with two transmembrane receptors, the type A CXCL8 receptor (CXCR1) and the type B CXCL8 receptor (CXCR2). In a previous work, we published the molecular modeling-driven structure activity relationship (SAR) results culminated in the discovery of R-(-)-2-[(4'-trifluoromethanesulphonyloxy)phenyl]-N-methanesulfonyl propionamide (19), in which an unusual aryltriflate moiety was embedded. Although triflates are broadly used in organic synthesis, this group is scarcely used in medicinal chemistry programs. Here we detail the drug profiling-driven approach used for the selection and characterization of 19, the most potent dual CXCR1 and CXCR2 noncompetitive inhibitor described to date. Reported data suggest that the aryltriflate moiety might represent a valid choice for the selection of clinical candidates with suitable druglike properties.

New spiro[chromane-2,4'-piperidine] and spiro[benzofuran-2,4'-piperidine] hydroxamic acid derivatives as HDAC inhibitors have been identified by combining privileged structures with a hydroxamic acid moiety as zinc binding group. The compounds were evaluated for their ability to inhibit nuclear extract HDACs and for their in vitro antiproliferative activity on different tumor cell lines. This work resulted in the discovery of spirocycle 30d that shows good oral bioavailability and tumor growth inhibition in an HCT-116 murine xenograft model.

Parallel artificial membrane permeability assay (PAMPA) is arising in ADMET screening as a powerful tool to determine the passive permeability of new potential chemical entities. In an attempt to set up a sensitive high throughput method to assess passive blood-brain barrier (BBB) penetration we focused our attention on the effect of solvent and the influence of phospholipids on the permeability in PAMPA. Moreover, the high throughput nature of the assay was maximized by decreasing the incubation time and performing the assay in a cassette mode. UPLC system coupled with a mass spectrometer enormously reduces the analytical time, contemporaneously increasing the sensitivity of the method. P(app) values obtained from PAMPA were compared to permeability values from MDCKII-MDR1 assay. Evaluation of the two in vitro models with in vivo data was performed to test the predicting capacity of the two methods. Their contemporary assessment was shown to be an helpful tool in understanding the prevalent mechanism of penetration through the BBB.

We designed 39 new 2-phenylindole derivatives as potential anticancer agents bearing the 3,4,5-trimethoxyphenyl moiety with a sulfur, ketone, or methylene bridging group at position 3 of the indole and with halogen or methoxy substituent(s) at positions 4-7. Compounds 33 and 44 strongly inhibited the growth of the P-glycoprotein-overexpressing multi-drug-resistant cell lines NCI/ADR-RES and Messa/Dx5. At 10 nM, 33 and 44 stimulated the cytotoxic activity of NK cells. At 20-50 nM, 33 and 44 arrested >80% of HeLa cells in the G2/M phase of the cell cycle, with stable arrest of mitotic progression. Cell cycle arrest was followed by cell death. Indoles 33, 44, and 81 showed strong inhibition of the SAG-induced Hedgehog signaling activation in NIH3T3 Shh-Light II cells with IC50 values of 19, 72, and 38 nM, respectively. Compounds of this class potently inhibited tubulin polymerization and cancer cell growth, including stimulation of natural killer cell cytotoxic activity and repression of Hedgehog-dependent cancer.

The Chlorophyte Parietochloris incisa comb. nov (Trebuxiophyceae) was found to be the richest plant source of the pharmaceutically valuable long-chain polyunsaturated fatty acid (PUFA), arachidonic acid (20:4ω6, AA). Over 90% of total AA are deposited in triacylglycerols (TAG). Under nitrogen starvation, the fatty acid content constituted over 35% of dry weight and the proportion of AA exceeded 60% of total fatty acids. Consequently, we obtained an AA content of over 20%. This is, to the best of our knowledge, the highest reported content of any PUFA in algae. Increasing the biomass concentration resulted in an enhancement of both the proportion of AA and the fatty acid content. We hypothesize that one of the roles of TAG in P. incisa is to serve as a reservoir of AA that can be used for the construction of membranal lipids.

We describe 1,3,4-oxadiazole-containing hydroxamates (2) and 2-aminoanilides (3) as histone deacetylase inhibitors. Among them, 2t, 2x, and 3i were the most potent and selective against HDAC1. In U937 leukemia cells, 2t was more potent than SAHA in inducing apoptosis, and 3i displayed cell differentiation with a potency similar to MS-275. In several acute myeloid leukemia (AML) cell lines, as well as in U937 cells in combination with doxorubicin, 3i showed higher antiproliferative effects than SAHA.

Treatment of the microalga Porphyridium cruentum with salicylhydroxamic acid (SHAM) inhibited growth and affected fatty acid composition. At a relatively low concentration (40 μM) SHAM predominantly inhibits Δ6 desaturation. The effect of the inhibitor was most intense in phosphatidylcholine (PC) and phosphatidylethanolamine, in which the proportions of the downstream products of the Δ6 desaturase were reduced, whereas that of the substrate, 18:2, increased. As a result of the availability of 18:2, 18:3ω3, which under normal conditions is not observed, appeared predominantly in chloroplastic lipids. Pulse labeling with linoleic acid has shown that SHAM inhibits Δ6 desaturation almost immediately, suggesting an apparent inhibition of the activity of the desaturase, rather than its synthesis or that of its cofactors. Furthermore, the addition of γ-linolenic acid to SHAM-inhibited cultures relieved the inhibition. Following exposure to the inhibitor, 18:3ω3 appeared first in chloroplastic glycolipids and only later in PC, indicating that the former are the substrates for the first dedicated step of the proposed ω3 pathway in this alga.

The effects of biomass concentration and growth temperature on the molecular species composition of the major galactolipids of the red microalga Porphyridium cruentum Nag. were detmined. At lower biomass concentrations, the Δ17 desaturation of arachidonic acid to eicosapentaenoic acid (20:5) was enhanced in both prokaryotic-type and eukalyotic-type molecular species of monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol. We suggest that chloroplastic Δ17 desaturation is correlated with the availability of light. A reduction in the growth temperature led to an increase in the proportion of the eukalyotic molecular species of MGDG, especially for 20:5/ 20:5 MGDG, These results suggest that this molecular species, and perhaps eukaryotic molecular species in general, may play a role in the adaptation of cells to low growth temperatures.

Histone Deacetylases (HDACs) have become important targets for the treatment of cancer and other diseases. In previous studies we described the development of novel spirocyclic HDAC inhibitors based on the combination of privileged structures with hydroxamic acid moieties as zinc binding group. Herein, we report further explorations, which resulted in the discovery of a new class of spiro[2 H -(1,3)-benzoxazine-2,4′-piperidine] derivatives. Several compounds showed good potency of around 100 nM and less in the HDAC inhibition assays, submicromolar IC 50 values when tested against tumour cell lines and a remarkable stability in human and mouse microsomes. Two representative examples exhibited a good pharmacokinetic profile with an oral bioavailability equal or higher than 35% and one of them studied in an HCT116 murine xenograft model showing a robust tumour growth inhibition. In addition, the two benzoxazines were found to have a minor affinity for the hERG potassium channel compared to their corresponding ketone analogues.

An open letter written by the Global CRO Council for Bioanalysis (GCC) describing the GCC survey results on stability data from co-administered and co-formulated drugs was sent to multiple regulatory authorities on 14 December 2011. This letter and further discussions at different GCC meetings led to subsequent recommendations on this topic of widespread interest within the bioanalytical community over the past 2 years.

A series of spiro[chromane-2,4′-piperidine] derivatives based on a previously published lead benzyl spirocycle 1 and bearing various N-aryl and N-alkylaryl substituents on the piperidine ring were prepared as novel histone deacetylase (HDAC) inhibitors. The compounds were evaluated for their abilities to inhibit nuclear HDACs, their in vitro antiproliferative activities, and in vitro ADME profiles. Based on these activities, 4-fluorobenzyl and 2-phenylethyl spirocycles were selected for further characterization. In vivo pharmacokinetic (PK) studies showed that both compounds exhibit an overall lower clearance rate, an increased half-life, and higher AUCs after intravenous and oral administration than spiropiperidine 1 under the conditions used. The improved PK behavior of these two compounds also correlated with superior in vivo antitumor activity in an HCT-116 xenograft model.

A series of N-alkyl 1-ary1-5-(1H-pyrrol-1-yl)-1H-pyrazole-3-carboxamides were synthesized as new ligands of the human recombinant receptor hCB(1). n-Alkyl carboxamides brought out different SARs from the branched subgroup. Unsubstituted pyrrole derivatives bearing a tert-alkyl chain at the 3-carboxamide nitrogen showed greater hCB1 receptor affinity than the corresponding unbranched compounds. In particular, the tert-butyl group as a chain terminal moiety strongly improved hCB(1) receptor affinity (compound 24: K(i); = 45.6 nM; 29: K(i) = 37.5 nM). Acute administration of either compound 12 or 29 resulted in a specific, dose-dependent reduction in food intake in rats. Such results provide an useful basis for the design of new CB(1) ligands. (C) 2010 Elsevier Masson SAS. All rights reserved.

The histone deacetylases (HDACs) are able to regulate gene expression, and histone deacetylase inhibitors (HDACi) emerged as a new class of agents in the treatment of cancer as well as other human disorders such as neurodegenerative diseases. In the present investigation, we report on the synthesis and biological evaluation of compounds derived from the expansion of a HDAC inhibitor scaffold having N-hydroxy-3-phenyl-2-propenamide and N-hydroxy-3-(pyridin-2-yl)-2-propenamide as core structures and containing a phenyloxopropenyl moiety, either unsubstituted or substituted by a 4-methylpiperazin-1-yl or 4-methylpiperazin-1-ylmethyl group. The compounds were evaluated for their ability to inhibit nuclear HDACs, as well as for their in vitro antiproliferative activity. Moreover, their metabolic stability in microsomes and aqueous solubility were studied and selected compounds were further characterized by in vivo pharmacokinetic experiments. These compounds showed a remarkable stability in vivo, compared to hydroxamic acid HDAC inhibitors that have already entered clinical trials. The representative compound 30b showed in vivo antitumor activity in a human colon carcinoma xenograft model.

Pharmacophore-based structural identification, synthesis, and structure -activity relationships of a new class of muscarinic M3 receptor antagonists, the diaryl imidazolidin-2-one derivatives, are described. The versatility of the discovered scaffold allowed for several structural modifications that resulted in the discovery of two distinct classes of compounds, specifically a class of tertiary amine derivatives (potentially useful for the treatment of overactive bladder by oral administration) and a class of quaternary ammonium salt derivatives (potentially useful for the treatment of respiratory diseases by the inhalation route of administration). In this paper, we describe the synthesis and biological activity of tertiary amine derivatives. For these compounds, selectivity for the M3 receptor toward the M2 receptor was crucial, because the M2 receptor subtype is mainly responsible for adverse systemic side effects of currently marketed muscarinic antagonists. Compound 50 showed the highest selectivity versus M2 receptor, with binding affinity for M3 receptor Ki ) 4.8 nM and for M2 receptor Ki ) 1141 nM. Functional in vitro studies on selected compounds confirmed the antagonist activity toward the M3 receptor and functional selectivity toward the M2 receptor.

Lead optimization requires rapid bio-analytical turnover for the generation of early absorption, distribution, metabolism, excretion (ADME) and pharmacokinetics (PK) data maintaining a high quality level. Therefore, one of the major challenges in the bio-analytical field is to achieve faster and more sensitive quantification protocols. In the present communication, a comparison between HPLC and ultra performance liquid chromatography (UPLC) performances in terms of sensitivity and resolution is shown using a pharmakokinetic study and a metabolism study as models. The studies highlight the features of the new technology and the resulting impact in the PK throughput and in the characterization of isomeric metabolites using UPLC/MS/MS technique.

Flurbiprofen, a nonsteroidal antiinflammatory drug (NSAID), has been recently described to selectively inhibit beta-amyloid(1)(-)(42) (Abeta42) secretion, the most toxic component of the senile plaques present in the brain of Alzheimer patients. The use of this NSAID in Alzheimer's disease (AD) is hampered by a significant gastrointestinal toxicity associated with cyclooxygenase (COX) inhibition. New flurbiprofen analogues were synthesized, with the aim of increasing Abeta42 inhibitory potency while removing anti-COX activity. In vitro ADME developability parameters were taken into account in order to identify optimized compounds at an early stage of the project. Appropriate substitution patterns at the alpha position of flurbiprofen allowed for the complete removal of anti-COX activity, while modifications at the terminal phenyl ring resulted in increased inhibitory potency on Abeta42 secretion. In rats, some of the compounds appeared to be well absorbed after oral administration and to penetrate into the central nervous system. Studies in a transgenic mice model of AD showed that selected compounds significantly decreased plasma Abeta42 concentrations. These new flurbiprofen analogues represent potential drug candidates to be developed for the treatment of AD.

We have hypothesized that among algae of alpine environment there could be strains particularly rich in long chain polyunsaturated fatty acids (LC-PUFA). Indeed, the chlorophyte (Trebuxiophyceae) Parietochloris incisa isolated from Mt. Tateyama, Japan, was found to be the richest plant source of the pharmaceutically valuable LC-PUFA, arachidonic acid (AA, 20:4omega6). The alga is also extremely rich in triacylglycerols (TAG), which reaches 43% (of total fatty acids) in the logarithmic phase and up to 77% in the stationary phase. In contrast to most algae whose TAG are made of mainly saturated and monounsaturated fatty acids, TAG of P. incisa are the major lipid class where AA is deposited, reaching up to 47% in the stationary phase. Except for the presence of AA, the PUFA composition of the chloroplastic lipids resembled that of green algae, consisting predominantly of C(16) and C(18) PUFAs. The composition of the extrachloroplastic lipids is rare, including phosphatidylcholine (PC), phosphatidylethanolamine (PE) as well as diacylglyceryltrimethylhomoserine (DGTS). PC and PE are particularly rich in AA and are also the major depots of the presumed precursors of AA, l8:3omega6 and 20:3omega6, respectively.

The freshwater green microalga Parietochloris incisa is the richest known plant source of the polyunsaturated fatty acid (PUFA), arachidonic acid (20:4o6, AA). While many microalgae accumulate triacylglycerols (TAG) in the stationary phase or under certain stress conditions, these TAGare generally made of saturated and monounsaturated fatty acids. In contrast, most cellular AA of P. incisa resides in TAG. Using various inhibitors, we have attempted to find out if the induction of the biosynthesis of AA and the accumulation of TAGare codependent. Salicylhydroxamic acid (SHAM) affected a growth reduction that was accompanied with an increase in the content of TAGfrom 3.0 to 6.2% of dry weight. The proportion of 18:1 increased sharply in all lipids while that of 18:2 and its down stream products, 18:3o6, 20:3o6 and AA, decreased, indicating an inhibition of the 12 desaturation of 18:1. Treatment with the herbicide SAN 9785 significantly reduced the proportion of TAG. However, the proportion of AA in TAG, as well as in the polar lipids, increased. These findings indicate that while there is a preference for AA as a building block of TAG, the latter can be produced using other fatty acids, when the production of AA is inhibited. On the other hand, inhibiting TAGconstruction did not affect the production of AA. In order to elucidate the possible role of AA in TAGwe have labeled exponential cultures of P. incisa kept at 25 C with [1- 14 C]arachidonic acid and cultivated the cultures for another 12 h at 25, 12 or 4 C. At the lower temperatures, labeled AA was transferred from TAGto polar lipids, indicating that TAGof P. incisa may have a role as a depot of AA that can be incorporated into the membranes, enabling the organism to quickly respond to low temperature-induced stress. # 2002 Published by Elsevier Science Ltd.

Many microalgae are known to accumulate triacylglycerols (TAGs), especially under nitrate starvation. Generally, these TAGs are predominantly constructed of saturated and monounsaturated fatty acids. In contrast, the TAGs of the red microalga Porphyridium cruentum are rich in arachidonic acid (AA, 20:4 omega6) and eicosapentaenoic acid (EPA, 20:5 omega3). A mutant of this alga, impaired of growth at suboptimal temperatures, was shown to have reduced levels of EPA and of the eukaryotic molecular species of monogalactosyldiacylglycerol (MGDG) and an elevated level of TAG. Labelling experiments have shown that labelling of wild-type TAGs decreased, whereas that of the mutant remained high. Contemporarily, eukaryotic MGDG of the mutant was less labelled. Similarly, TAGs of the green alga Tl2, which can grow at a low temperature, are extremely rich in AA. We have labelled exponentially growing cultures of T12 kept at 25 degrees C with radioactive AA and cultivated the cultures for a further 12 h at 25 degrees C, 12 degrees C or 4 degrees C. At low temperatures, labelled AA was transferred from TAGs to polar lipids. These findings may indicate that polyunsaturated fatty acids that can be incorporated into the membranes, enabling the organism to quickly respond to low-temperature-induced stress.

The biosynthetic pathways in algae that produce PUFAs of no more than 18 carbon atoms are presumed to be similar to those of higher plants (1). However, the biosynthesis of C20 PUFAs in various algae appears to be different. The few detailed studies suggest that the biosynthesis of eicosapentaenoic acid (EPA, 20:5ω3) from C18 precursors is entirely cytoplasmatic (2 – 4). Feeding external fatty acids to P. cruentum indicated the existence of two possible pathways as outlined in sequences I and II, respectively (unpublished data).

The lipid composition in higher plants and algae can be modulated by changing growth conditions such as temperature and light intensity. One of the major effects is on the level of fatty acid desaturation. Polyunsaturated fatty acids (PUFAs), especially those of the ω3 family appear to be essential for survival at low temperatures (Wada and Murata, 1989; Browse and Somerville, 1991). While there is an abundance of information pertaining to the effect of environmental conditions on the fatty acid composition of algae (Cobelas, 1989), very little is known concerning the effects on the molecular species composition of the individual lipids. The lipids of higher plants and algae are further divided according to their molecular species composition. The diacylglycerol (DAG) moieties of the prokaryotic species of galactolipids are assembled in the chloroplast and are characterized by the presence of C16 acyl groups at their sn-2 position, while the DAGs of eukaryotic species originate in the cytoplasm and contain C18 acyl groups in their sn-2 position. The aim of the present work was to study the effect of cultivation temperature and biomass density on the molecular species composition of the major galactolipids, MGDG and DGDG, in Porphyridium cruentum.

Aim: Nowadays, there is a great interest in the therapeutic potential of sigma1 receptor ligands for treating different CNS pathologies. Our previous investigations led to identify (R)-RC-33 as a potent and selective S1R agonist. Results: Herein, we report the gram-scale synthesis, pharmacokinetic profile and CNS distribution of (R)-RC-33 in the mouse to determine the most suitable dosage schedule for in vivo administration. For comparative purposes, the same experiments were also performed with PRE-084, the most widely used S1R agonist commonly in pharmacological experiments. Discussion: (R)-RC-33 shows a similar pharmacokinetic profile and a better CNS distribution when compared with PRE-084. Conclusion: (R)-RC-33 may be a promising candidate for in vivo studies in animal models of neurodegenerative diseases.

The fresh-water green alga Parietochloris incisa is the richest plant source of the PUFA arachidonic acid (20:4n-6, AA). To elucidate the biosynthesis of AA in this alga we labeled cultures of P. incisa with radioactive precursors. Pulse chase labeling with acetate resulted in its incorporation via the de novo biosynthesis pathway of FA. However, labeled acetate was also utilized for the elongation of C16 and C18 PUFA. Labeling with [1-14C]oleic acid has shown that the first steps of the lipid-linked FA desaturations utilize cytoplasmic lipids. PC and diacylglyceryltrimethylhomoserine are the major lipids involved as acyl carriers for the delta12 and delta6 desaturations of oleic acid, leading sequentially to linoleic and gamma-linolenic acids. The latter is released from its lipid carrier and elongated to 20:3n-6, which is reincorporated primarily into PE and PC and finally desaturated to AA. Galactolipids, mostly monogalctosyldiacyl-glycerol (MGDG), serve as substrates for the chloroplastic delta12 desaturase and, apparently, the omega3 desaturation, common to higher plants and many green algae. The predominant sequence desaturates the 18:1/16:0 molecular species of MGDG stepwise to the 18:3n-3/16:3n-3 molecular species similar to the prokaryotic pathway of higher plants and green algae.