Cyclic peptides

Multiple strains of Bacillus spp. were demonstrated to stimulate plant defence responses. However, very little is known about the nature of molecular determinants secreted by these Gram-positive bacteria that are responsible for the elicitation of the induced systemic resistance (ISR) phenomenon. This study shows that the lipopeptides surfactins and fengycins may be involved in this elicitation process. In bean, pure fengycins and surfactins provided a significant ISR-mediated protective effect on bean plants, similar to the one induced by living cells of the producing strain S499. Moreover, experiments conducted on bean and tomato plants showed that overexpression of both surfactin and fengycin biosynthetic genes in the naturally poor producer Bacillus subtilis strain 168 was associated with a significant increase in the potential of the derivatives to induce resistance. In tomato cells, key enzymes of the lipoxygenase pathway appeared to be activated in resistant plants following induction by lipopeptide overproducers. To our knowledge, such lipopeptides constitute a novel class of compounds from non-pathogenic bacteria that can be perceived by plant cells as signals to initiate defence mechanisms.

This study highlights the use of low-cost agro-industrial raw material e date molasses for fermentative production of biosurfactants. Date palm (Phoenix dactylifera L.) is the primary crop in Oman, which shares 82% of all fruit crops production in the country. When date molasses was used as the sole carbon and energy source for biosurfactant production using Bacillus subtilis B20, a product yield of 2.29 AE 0.38 g/l was obtained. The biosurfactant reduced surface tension and interfacial tension from 60 to 25 mN/m to 27 and 5.02 mN/m respectively. It also showed significant stability under a wide range of temperatures, pH and salt concentrations. Additional 9.7% oil was recovered through core-flood studies, accessing the potential of biosurfactant to enhance oil recovery under reservoir conditions. Current studies showed date molasses could be suitable for use in the production of biosurfactant and it has the potential for use in enhancing oil recovery.

The cyanobacteria or "blue-green algae", as they are commonly termed, comprise a diverse group of oxygenic photosynthetic bacteria that inhabit a wide range of aquatic and terrestrial environments, and display incredible morphological diversity. Many aquatic, bloom-forming species of cyanobacteria are capable of producing biologically active secondary metabolites, which are highly toxic to humans and other animals. From a toxicological viewpoint, the cyanotoxins span four major classes: the neurotoxins, hepatotoxins, cytotoxins, and dermatoxins (irritant toxins). However, structurally they are quite diverse. Over the past decade, the biosynthesis pathways of the four major cyanotoxins: microcystin, nodularin, saxitoxin and cylindrospermopsin, have been genetically and biochemically elucidated. This review provides an overview of these biosynthesis pathways and additionally summarizes the chemistry and toxicology of these remarkable secondary metabolites.

Despite significant advances in the management of immunosuppressed patients, invasive fungal infections remain an important life-threatening complication. In the last decade several new antifungal agents, including compounds in pre-existing classes (new generation of triazoles, polyenes in lipid formulations) and novel classes of antifungals with a unique mechanism of action (echinocandins), have been introduced in clinical practice. Ongoing and future studies will determine their exact role in the management of different mycoses. The acceleration of antifungal drug discovery offers promise for the management of these difficult to treat opportunistic infections.

Research in anthelmintic pharmacology faces a grim future. The parent field of veterinary parasitology has seemingly been devalued by governments, universities and the animal industry in general. Primarily due to the success of the macrocyclic lactone anthelmintics in cattle, problems caused by helminth infections are widely perceived to be unimportant. The market for anthelmintics in other host species that are plagued by resistance, such as sheep and horses, is thought to be too small to sustain a discovery program in the animal heallth pharmaceutical industry. These attitudes are both alarming and foolish. The recent history of resistance to antibiotics provides more than adequate warning that complacency about the continued efficacy of any class of drugs for the chemotherapy of an infectious disease is folly. Parasitology remains a dominant feature of veterinary medicine and of the animal health industry. Investment into research on the basic and clinical pharmacology of anthelmintics is essential to ensure chemotherapeutic control of these organisms into the 21st century. In this article, we propose a set of questions that should receive priority for research funding in order to bring this field into the modern era. While the specific questions are open for revision, we believe that organized support of a prioritized list of research objectives could stimulate a renaissance in research in veterinary helminthology. To accept the status quo is to surrender.

Aim: Test of Bacillus subtilis strain GA1 for its potential to control grey mould disease of apple caused by Botrytis cinerea. Methods and Results: GA1 was first tested for its ability to antagonize in vitro the growth of a wide variety of plant pathogenic fungi responsible for diseases of economical importance. The potential of strain GA1 to reduce post-harvest infection caused by B. cinerea was tested on apples by treating artificially wounded fruits with endospore suspensions. Strain GA1 was very effective at reducing disease incidence during the first 5 days following pathogen inoculation and a 80% protection level was maintained over the next 10 days. Treatment of fruits with an extract of GA1 culture supernatant also exerted a strong preventive effect on the development of grey mould. Further analysis of this extract revealed that strain GA1 produces a wide variety of antifungal lipopeptide isomers from the iturin, fengycin and surfactin families. A strong evidence for the involvement of such compounds in disease reduction arose from the recovery of fengycins from protected fruit sites colonized by bacterial cells.

The investigation on microcystin topics is increasing due to the related ecological and public health risks. Recent investigation confirms a gap in establishing global patterns relating a particular environment to the bloom occurrence of a species and the production of certain microcystin variants. All the results concerning the environmental effects on the microcystin synthesis of one species must be checked in the light of genome diversity. Thus, the poisoning risks of a bloom depend on the strain causing toxicity. To be more effective, specific water treatment methods are required for blooms of different microcystin producing species (such as colonial and filamentous cyanobacteria found in stratified and unstratified water bodies, respectively). With the increasing number of new microcystin variants discovered, the development of new rapid, inexpensive and sensitive enough monitoring methods to promptly screen simultaneously a great diversity of toxins and also check their toxic effects is becoming necessary.

The genome of plant-associated Bacillus amyloliquefaciens FZB42 harbors an array of giant gene clusters involved in synthesis of lipopeptides and polyketides with antifungal, antibacterial and nematocidal activity. Five gene clusters, srf, bmy, fen, nrs, dhb, covering altogether 137 kb, were shown to direct synthesis of the cyclic lipopeptides surfactin, bacillomycin, fengycin, an unknown peptide, and the iron-siderophore bacillibactin. In addition, one gene cluster encoding enzymes involved in synthesis and export of the antibacterial dipeptide bacilysin is also functional in FZB42. Three gene clusters, mln, bae, and dfn, with a total size of 199 kb were shown to direct synthesis of the antibacterial acting polyketides macrolactin, bacillaene, and difficidin. In total, FZB42 dedicates about 340 kb, corresponding to 8.5% of its total genetic capacity, to synthesis of secondary metabolites. On the contrary, genes involved in ribosome-dependent synthesis of lantibiotics and other peptides are scarce. Apart from two incomplete gene clusters directing immunity against mersacidin and subtilin, only one peptide-like compound has been detected in the culture fluid that inhibits the growth of B. subtilis lacking the alternative sigma factor W.

The investigation on microcystin topics is increasing due to the related ecological and public health risks. Recent investigation confirms a gap in establishing global patterns relating a particular environment to the bloom occurrence of a species and the production of certain microcystin variants. All the results concerning the environmental effects on the microcystin synthesis of one species must be checked in the light of genome diversity. Thus, the poisoning risks of a bloom depend on the strain causing toxicity. To be more effective, specific water treatment methods are required for blooms of different microcystin producing species (such as colonial and filamentous cyanobacteria found in stratified and unstratified water bodies, respectively). With the increasing number of new microcystin variants discovered, the development of new rapid, inexpensive and sensitive enough monitoring methods to promptly screen simultaneously a great diversity of toxins and also check their toxic effects is becoming necessary. r 2004 Elsevier Inc. All rights reserved.

It has been long experimentally demonstrated that human alpha-fetoprotein (HAFP) has an ability to bind immobilized estrogens with the most e±ciency for synthetic estrogen analog À À À diethylstilbestrol (DES). However, the question remains why the human AFP (HAFP), unlike rodent AFP, cannot bind free estrogens. Moreover, despite the fact that AFP was¯rst discovered more than 50 years ago and is presently recognized as a \golden standard" among oncobiomarkers, its three-dimensional (3D) structure has not been experimentally solved yet. In this work using MODELLER program, we generated 3D model of HAFP on the basis of homology with human serum albumin (HSA) and Vitamin DÀbinding protein (VTDB) with subsequent molecular docking of DES to the model structure and molecular dynamics (MD) simulation study of the complex obtained. The model constructed has U-shaped structure in which a cavity may be distinguished. In this cavity the putative estrogen-binding site is localized. Validation by RMSD calculation and with the use of PROCHECK program showed good quality of the model and stability of extended region of four alpha-helical structures that contains putative hormone-binding residues. Data extracted from MD simulation trajectory allow proposing two types of interactions between amino acid residues of HAFP and DES molecule: (1) hydrogen bonding with involvement of residues S445, R452, and E551; (2) hydrophobic interactions with participation of L138, M448, and M548 residues. A suggestion is made that immobilization of the hormone using a long spacer provides delivery of the estrogen molecule to the binding site and, thereby, facilitates interaction between HAFP and the hormone.

The investigation on microcystin topics is increasing due to the related ecological and public health risks. Recent investigation confirms a gap in establishing global patterns relating a particular environment to the bloom occurrence of a species and the production of certain microcystin variants. All the results concerning the environmental effects on the microcystin synthesis of one species must be checked in the light of genome diversity. Thus, the poisoning risks of a bloom depend on the strain causing toxicity. To be more effective, specific water treatment methods are required for blooms of different microcystin producing species (such as colonial and filamentous cyanobacteria found in stratified and unstratified water bodies, respectively). With the increasing number of new microcystin variants discovered, the development of new rapid, inexpensive and sensitive enough monitoring methods to promptly screen simultaneously a great diversity of toxins and also check their toxic effects is becoming necessary. r 2004 Elsevier Inc. All rights reserved.

The first total synthesis of FR-901375, a novel bicyclic depsipeptide isolated from the fermentation broth of Pseudomonas chloroaphis No. 2522, has been achieved. The synthetic approach involves 13 reaction steps and is achieved in 12% overall yield. The key points in the successful synthetic strategy are a concise asymmetric synthesis of the key building block (3R,4E)-3-hydroxy-7-mercapto-4-heptenoic acid, a mild Mitsunobu macrolactonization step, and an I 2 -mediated deprotection with concomitant disulfide-bridge formation.

The dynamics of cyclic peptide destruxins (dtxs) produced by Metarhizium anisopliae strains V245 and V275 were monitored both on solid and in liquid media. The results showed that both strains did not produce dtxs in large-scale fermenter cultures or solid Czapek Dox (CD) agar. Production of the major dtxs A and B could be determined in both strains when grown

In this work, the potential of Bacillus subtilis strain M4 at protecting plants against fungal diseases was demonstrated in different pathosystems. We provide evidence for the role of secreted lipopeptides, and more particularly of fengycins, in the protective effect afforded by the strain against damping-off of bean seedlings caused by Pythium ultimum and against gray mold of apple in post-harvest disease. This role was demonstrated by the strong biocontrol activity of lipopeptide-enriched extracts and through the detection of inhibitory quantities of fengycins in infected tissues. Beside such a direct antagonism of the pathogen, we show that root pre-inoculation with M4 enabled the host plant to react more efficiently to subsequent pathogen infection on leaves. Fengycins could also be involved in this systemic resistance-eliciting effect of strain M4, as these molecules may induce the synthesis of plant phenolics involved in or derived from the defense-related phenylpropanoid metabolism. Much remains to be discovered about the mechanisms by which Bacillus spp suppress disease. Through this study on strain M4, we reinforce the interest in B. subtilis as a pathogen antagonist and plant defense-inducing agent. The secretion of cyclic fengycin-type lipopeptides may be tightly related to the expression of these two biocontrol traits.

The effects of microcystins (MCs) from cyanobacterial cells on the enzymatic activities of acid and alkaline phosphatases (ACP and ALP) from liver, kidney and gill tissues, and the histopathological changes in freshwater Tilapia fish (Oreochromis sp.) were investigated under laboratory conditions. Fish were exposed to cyanobacterial cells (60.0 mg MC-LR/fish per day) through their diet at different exposure times (14 and 21 days). The cells were fed to the fish in two types of oral administration: mixed with a commercial fish food or crushed into a commercial fish food so that the toxins were released. ACP and ALP activities changed in response to MCs in a time-dependent manner, and these changes were more prominent in liver and kidney. The way the MCs were administered had no influence on the biochemical parameters. Similarly, the most severe histopathological changes were observed in the same two organs, although the gills and intestines were also affected. The parenchymal architecture of the liver was dissolved, and round hepatocytes with the appearance of pyknotic nuclei were detected. Kidney lesions consisted of the dilation of Bowman's space and necrotic epithelial cells with pyknotic nuclei in the tubules. These findings suggest that low and repeated doses of MC-LR from cyanobacterial cells induce toxicity in tilapia fish although no adverse effects were detected q

The application of photoinduced electron transfer (PET) for the construction of heterocyclic ring systems is an appealing route in synthetic organic photochemistry. Electronically excited carbonyl chromophors in ketones, aldehydes, amides, or imides are strong electron acceptors that oxidize alkenes, amines, thioethers, or carboxylates. In subsequent steps, the radical anions formed thereof either are operating as secondary electron donors and initiate a photon-driven chain reaction or combine with electrophilic species and form products. These reactions are applied in the synthesis of heterocyclic compounds. The basic structures of these target molecules are bicyclic tertiary amines from the pyrrolizidine, benzopyrrolizidine, and indolizidine families, cyclic oligopeptides, macrocyclic ring systems, and many more. field of organic photochemistry: electron transfer, photoinduced radical reactions, cycloadditions of aromatic compounds, and application of these reactions to organic synthesis. Further research activities concern the use of renewable resources from agricultural origin for the production of fine chemicals and the synthesis of new organic semiconductor materials for microelectronics.

Since RGD peptides (R: arginine; G: glycine; D: aspartic acid) have been found to promote cell adhesion in 1984 (Cell attachment activity of fibronectin can be duplicated by small synthetic fragments of the molecule, Nature 309 , numerous materials have been RGD functionalized for academic studies or medical applications. This review gives an overview of RGD modified polymers, that have been used for cell adhesion, and provides information about technical aspects of RGD immobilization on polymers. The impacts of RGD peptide surface density, spatial arrangement as well as integrin affinity and selectivity on cell responses like adhesion and migration are discussed. r

Bikalga is a Hibiscus sabdariffa seed fermented condiment widely consumed in Burkina Faso and neighboring countries. The fermentation is dominated by Bacillus subtilis group species. Ten B. subtilis subsp. subtilis (six isolates) and Bacillus licheniformis (four isolates) isolated from traditional Bikalga were examined for their antimicrobial activity against a panel of 36 indicator organisms including Gram-positive and Gram-negative bacteria and yeasts. The Bacillus spp. isolates showed variable inhibitory abilities depending on the method used. Both Gram-positive and Gram-negative bacteria were inhibited in the agar spot assay while only Gram-positive pathogens were inhibited in the agar well diffusion assay. Cell free supernatants (CFS) of pure cultures of 3 B. subtilis subsp. subtilis (G2, H4 and F1) strains inhibited growth of Listeria monocytogenes, Micrococcus luteus, Staphylococcus aureus and Bacillus cereus, while CFS of 2 B. licheniformis (E3 and F9) strains only inhibited M. luteus. The antimicrobial substance(s) produced by B. subtilis subsp. subtilis H4 was further characterized. The antimicrobial substance(s) produced by H4 was detected from mid-exponential growth phase. The activity was sensitive to protease and trypsin, but resistant to the proteolytic action of proteinase K and papain. Treatment with α-amylase and lipase II resulted in a complete loss of antimicrobial effect, indicating that a sugar moiety and lipid moiety are necessary for the activity. Treatment with mercapto-ethanol resulted in a significant loss, indicative of the presence of disulfide bridges. The antimicrobial activity of H4 was heat resistant and active at pH 3-10. PCR detection of yiwB, sboA, spoX, albA and spaS, etnS genes and genes coding for surfactins and plipastatins (fengycins) indicated a potential for subtilosin, subtilin and lipopeptide production, respectively. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was carried out and a single band of approximately 4 kDa had antimicrobial activity. Ultra high performance liquid chromatography-time of flight mass spectrometry (UHPLC-TOFMS) analysis of the 4 kDa band allowed identification of surfactin and a protein with a monoisotopic mass of 3346.59 Da, which is dissimilar in size to subtilosin and subtilin. Surfactin is a cyclic lipoheptapeptide, which contains a β-hydroxy fatty acid, but no di-sulfide bridges or sugar residues. The complete loss of activity upon amylase treatment indicates that surfactin was not responsible for the observed antimicrobial effect. However, it cannot completely be ruled out that surfactin acts synergistically with the detected protein, though further investigations are needed to confirm this.

Automated and manual deprotection methods for allyl/allyloxycarbonyl (Allyl/Alloc) were evaluated for the preparation of side-chain-to-side-chain cyclic peptides. Using a standard Allyl/Alloc deprotection method, a small library of cyclic peptides with lactam bridges (with seven amino acids) was prepared on an automatic peptide synthesizer. We demonstrate that the Guibe method for removing Allyl/Alloc protecting groups under specific neutral conditions [Pd(PPh3)4/PhSiH3)/DCM] can be a useful, efficient and reliable method for preparing long cyclic peptides on a resin. We have also manually synthesized a cyclic glucagon analogue containing 24 amino acid residues. These results demonstrated that properly controlled palladium-mediated deprotection of Allyl/Alloc protecting groups can be used to prepare cyclic peptides on the resin using an automated peptide synthesizer and cyclic peptides with a long chain.

Gene-encoded anti-microbial peptides (AMPs) are widespread in nature, as they are synthesized by microorganisms as well as by multicellular organisms from both the vegetal and the animal kingdoms. These naturally occurring AMPs form a first line of host defense against pathogens and are involved in innate immunity. Depending on their tissue distribution, AMPs ensure either a systemic or a local protection of the organism against environmental pathogens. They are classified into three major groups: (i) peptides with an a-helical conformation (insect cecropins, magainins, etc.), (ii) cyclic and open-ended cyclic peptides with pairs of cysteine residues (defensins, protegrin, etc.), and (iii) peptides with an over-representation of some amino acids (proline rich, histidine rich, etc.). Most AMPs display hydrophobic and cationic properties, have a molecular mass below 25-30 kDa, and adopt an amphipathic structure (a-helix, b-hairpin-like b-sheet, b-sheet, or a-helix/b-sheet mixed structures) that is believed to be essential to their anti-microbial action. Interestingly, in recent years, a series of novel AMPs have been discovered as processed forms of large proteins. Despite the extreme diversity in their primary and secondary structures, all natural AMPs have the in vitro particularity to affect a large number of microorganisms (bacteria, fungi, yeast, virus, etc.) with identical or complementary activity spectra. This review focuses on AMPs forming a-helices, b-hairpin-like b-sheets, bsheets, or a-helix/b-sheet mixed structures from invertebrate and vertebrate origins. These molecules show some promise for therapeutic use.

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Cyclic RGD peptide anchored sterically stabilized liposomes (RGD-SL) were investigated for selective and preferential presentation of carrier contents at angiogenic endothetial cells overexpressing avP.i integrins on and around tumor tissue and thus for assessing their targetabilty. Liposomes were prepared using distearoylphosphatidylcholine (DSPC). cholesterol and distearoylphosphatldylethanolaminepolyethyleneglycol-RGD peptide conjugate (DSPE-PEG-RGD) in a molar ratio 56:39:5. The control RAD peptide anchored sterically stabilized liposoines (RAD-SL) and liposome with 5 mol% PEG (SL) without peptide conjugate which had similar lipid composition were used for comparison. The average size of all liposome preparations prepared was approximately 105 nm and maximum drug entrapment was 10.2 ± 1.1%. In vitro endothelial cell binding of liposomes exhibited 7-fold higher binding of RGD-SL to HUVEC in comparison to the SL and RAD-SL. Spontaneous lung metastasis and angiogenesis assays show that RGD peptide anchored liposomes are sigtiilicantly (p < Q.Oi) effective in the prevention of lung metastasis and angiogenesis compared to free 5-FU. SL and RAD-SL. In therapeutic experiments, 5-FU, SL. RGD-SL and RAD-SL were administered intravenously on day 4 at ihe dose of 10 mg 5-FU/kg body weight I0BI6FIO tumor bearing BALB/cmice resulting in effective regression of tumors compared with free 5-FU, SL and RAD-SL. Results indicate that cyclic RGD peptide anchored sterically stabilized liposomes bearing 5-FU are significantly (j? < 0.01) active against primary tumor and metastasis than the non-targeted sterically stabilized liposomes and free drug. Thus cyclic RGD peptide anchored sterically stabilized liposomes hold potential of targeted cancer chemotherapeutics.

A panel of infectious disease specialists, clinical microbiologists and hospital epidemiologists of the five Swiss university hospitals reviewed the current literature on the treatment of invasive fungal infections in adults and formulated guidelines for the management of patients in Switzerland. For empirical therapy of Candida bloodstream infection, fluconazole is the drug of choice in non-neutropenic patients with no severe sepsis or septic shock or recent exposure to azoles. Amphotericin B deoxycholate or caspofungin would be the treatment option for patients with previous azole exposure. In neutropenic patients, empirical therapy with amphotericin B deoxycholate is considered first choice. In patients with severe sepsis and septic shock, caspofungin is the drug of first choice. For therapy of microbiologically-documented Candida infection, fluconazole is the drug of choice for infections due to C. albicans, C. tropicalis or C. parapsilosis. When infections are caused by C. glab...

In the current study, the toxicological mechanisms of microcystin-LR and its disadvantageous effects on Daphnia magna were examined. Survival rate, number of newborn, activity of several important enzymes [glutathione S-transferase (GST), lactate dehydrogenase (LDH), phosphatases, and glutathione], accumulated microcystins, and ultrastructural changes in different organs of Daphnia were monitored over the course of 21-day chronic tests. The results indicated that low concentrations of dissolved microcystin had no harmful effect on Daphnia. On the contrary, stimulatory effects were detected. In the presence of toxin at high dosage and for long-term exposure, GST and glutathione levels decreased significantly. The decreased enzyme activity in the antioxidant system probably was caused by detoxification reactions with toxins. And these processes of detoxification at the beginning of chronic tests may enable phosphatases in Daphnia magna to withstand inhibition by the toxins. At the same time, we also found that the LDH activity in test animals increased with exposure to microcystin-LR, indicating that adverse effects occurred in Daphnia. With microcystin given at a higher dosage or for a longer exposure, the effect on Daphnia magna was fatal. In the meantime, microcystin began to accumulate in Daphnia magna, and phosphatase activity started to be inhibited. From the ultrastructure results of cells in D. magna, we obtained new information: the alimentary canal may be the target organ affected by exposure of microcystins to D. magna. The results of the current study also suggested that the oxidative damage and PPI (protein phosphatase inhibition) mechanisms of vertebrates also are adapted to Daphnia. ' 2005 Wiley Periodicals, Inc. Environ Toxicol 20: 323-330, 2005

A computational approach for the design of a molecularly imprinted polymer (MIP) specific for Cyanobacterial toxin microcystin-LR is presented. By using molecular modeling software, a virtual library of functional monomers was designed and screened against the target toxin, employed as a template. The monomers giving the highest binding energy were selected and used in a simulated annealing (molecular dynamics) process to investigate their interaction with the template. The stoichiometric ratio observed from the simulated annealing study was used in MIP preparation for microcystin-LR. The monomers were copolymerized with a cross-linker in the presence of the template. A control (blank) polymer was prepared under the same conditions but in the absence of template. A competitive assay with microcystin-horseradish peroxidase conjugate was optimized and used to evaluate the affinity and cross-reactivity of the polymer. The performance of the artificial receptor was compared to the performance of monoclonal and polyclonal antibodies raised against the toxin. The results indicate that imprinted polymer has affinity and sensitivity comparable to those of polyclonal antibodies (the detection limit for microcystin-LR using the MIP-based assay was found to be 0.1 µg L -1 ), while superior chemical and thermal stabilities were obtained. Moreover, cross-reactivity to other toxin analogues was very low for the imprinted polymer, in contrast to the results achieved for antibodies. It is anticipated that the polymer designed could be used in assays, sensors, and solid-phase extraction.

Two unprecedented cyclic peptides, solomonamides A and B, were isolated from the marine sponge Theonella swinhoei. The structures were elucidated on the basis of comprehensive 1D and 2D NMR analysis and high-resolution mass spectrometry. A combined approach, involving Marfey's method, QM J based analysis, and DFT J/ 13 C calculations, was used for establishing the absolute configuration of the entire molecule. Solomonamide A showed in vivo anti-inflammatory activity.

Melanocortins affect multiple physiological responses, including sexual behaviors. Bremelanotide is a synthetic peptide melanocortin analog of α-melanocyte-stimulating hormone that is an agonist at melanocortin receptors MC3R and MC4R. Aim. To evaluate a single intranasal dose of bremelanotide for potential effects on physiological and subjective measurements of sexual arousal and desire in premenopausal women with sexual arousal disorder. Main Outcome Measures. Change in vaginal pulse amplitude during neutral and erotic videos after treatment with bremelanotide or placebo and subjects' perceptions of physiological and sexual response within 24 hours of treatment with bremelanotide or placebo. Methods. Eighteen premenopausal women with a primary diagnosis of female sexual arousal disorder were randomly assigned to receive a single intranasal dose of 20 mg bremelanotide or matching placebo in a double-blind manner during the first in-clinic treatment session, and the alternate medication during the second in-clinic treatment session. During each session, subjects viewed a 20-minute neutral video followed by a 20-minute sexually explicit video. Vaginal photoplethysmography was used to monitor vaginal vasocongestion and questionnaires were used to evaluate perceptions of sexual response within the following 24-hour period. Results. More women reported moderate or high sexual desire following bremelanotide treatment vs. placebo (P = 0.0114), and a trend toward more positive responses regarding feelings of genital arousal occurred after bremelanotide compared with placebo (P = 0.0833). Among women who attempted sexual intercourse within 24 hours after treatment, significantly more were satisfied with their level of sexual arousal following bremelanotide, compared with placebo (P = 0.0256). Vaginal vasocongestion did not change significantly while viewing erotic videos following bremelanotide administration compared with placebo. Conclusion. This preliminary evaluation suggests the potential for bremelanotide to positively affect desire and arousal in women with female sexual arousal disorder and indicates that bremelanotide is a promising candidate for further evaluation in an at-home study. Diamond LE, Earle DC, Heiman JR, Rosen RC, Perelman MA, and Harning R. An effect on the subjective sexual response in premenopausal women with sexual arousal disorder by bremelanotide (PT-141), a melanocortin receptor agonist. J Sex Med 2006;3:628-638.

The effects of microcystins from cyanobacterial cells on various oxidative stress biomarkers in liver, kidney and gill tissues in freshwater tilapia fish (Oreochromis sp.) were investigated under laboratory conditions. Microcystins are a family of cyclic peptide toxins produced by species of freshwater cyanobacteria (blue-green algae). Fish were exposed to the cyanobacterial cells in two ways: mixed with a commercial fish food or crushed into a commercial fish food so that the toxins were released. Two different exposure times were studied: 14 and 21 days. The oxidative status of fish was evaluated by analyzing the level of lipid peroxidation (LPO), as well as the activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR). The findings of the present investigation show that microcystins induce oxidative stress in a time-dependent manner and that the type of administration of the cyanobacterial cells influences the extent of these effects. Thus, the crushed cyanobacterial cells (released toxins) induced the antioxidant defences studied and increased the LPO level to a greater extent than the non-crushed cells. The liver was the most affected organ followed by kidney and gills. These results together with reports that fish can accumulate microcystins mean that cyanobacterial blooms are an important health, environmental and economic problem.

Microcystins are naturally occurring hepatotoxic cyclic heptapeptides produced by some toxic freshwater cyanobacterial species. In this study, crude extract of toxic cyanobacterial blooms from Dianchi Lake in southwestern China was used to determine the effects of microcystins on rape (Brassica napus L.) and rice (Oryza sativa L.). Experiments were carried out on a range of doses of the extract (equivalent

Human sexual response involves a complex sequencing of interrelated mind/body processes. Few treatment options exist that address the complex multilayered etiological determinants of female sexual dysfunction (FSD). Review and evaluate the clinical application of centrally acting agents for the treatment of FSD, with particular emphasis on recently released data on bremelanotide. Review of literature on the treatment of FSD. Approaches to FSD treatment have ranged from psychological counseling through a variety of medical interventions along the physiological pathways of sexual function and dysfunction. Despite a great deal of research, especially into hormonal and vasoactive substances, few therapeutics have broad consistent applicability and have withstood scientific scrutiny. Recent clinical trials have investigated the potential role of agents which act on the central nervous system for the treatment of FSD. While the recent data supporting the therapeutic use of centrally acting agents as a monotherapy for FSD are cautiously encouraging, there would seem to be tremendous promise for these centrally acting compounds to be integrated with treatment approaches that utilize other pathways in a multilayered, individualized approach to care.

Investigation of the MeOH extract obtained from the root of the Ziziphus mauritiana grown in Thailand resulted in the isolation of two 14-and 13-membered cyclic alkaloids, mauritine L (1) and mauritine M (2), and three known cyclopeptide alkaloids, nummularines H (3), B (4) and hemsine A (5). Their structures were elucidated on the basis of extensive NMR spectroscopic analysis. The first single crystal X-ray diffraction study of the 13-membered ring cyclopeptide, nummularine B methiodide (4 0 ), revealed all S configurations on the amino acid residues. The isolated alkaloids exhibited potent antiplasmodial activity against the parasite Plasmodium falciparum with the inhibitory concentration (IC 50 ) ranging from 3.7 to 10.3 lM. Compounds 2 and 3 also demonstrated antimycobacterial activity against Mycobacterium tuberculosis with the MIC of 72.8 and 4.5 lM, respectively.

The toxicity and metabolism of the cyanobacterial toxins microcystin-LR (MCLR), Dhb-microcystin-HtyR and nodularin were investigated in the cysts, nauplii and adults of the brine shrimp Artemia salina . The presence of the phase II detoxication system glutathione S-transferase (sGST) in these stages was shown using different substrates. Exposure of adult A. salina to the toxins led to an elevation of GST activity in vivo. All three toxins were conjugated to glutathione via GST, which has been shown as an initial step of microcystin and nodularin detoxication. #

Microsystin-LR is one of the most widespread and dangerous toxins produced by the freshwater Cyanobacteria. The contamination of water supplies with microcystin-LR has been reported in several areas around the world and the development of an easy-to-use, rapid, robust and inexpensive sensor for this toxin is urgently required. In this work an artificial receptor for microcystin-LR was synthesised using the technique of molecular imprinting. The composition of the molecularly imprinted polymer (MIP) was optimised using computer modelling. The synthesised polymer was used both as a material for solid-phase extraction (SPE) and as a sensing element in a piezoelectric sensor. Using the combination of SPE followed by detection with a piezoelectric sensor the minimum detectable amount of toxin was 0.35 nM. The use of MIP Á/SPE provided up to 1000 fold preconcentration, which was more than sufficient for achieving the required detection limit for microcystin-LR in drinking water (1 nM). This work is the first example where the same MIP receptor has been used successfully for both SPE and the corresponding sensor. #

We report an atomistic physical model for the passive membrane permeability of cyclic peptides. The computational modeling was performed in advance of the experiments and did not involve the use of "training data". The model explicitly treats the conformational flexibility of the peptides by extensive conformational sampling in low (membrane) and high (water) dielectric environments. The passive membrane permeabilities of 11 cyclic peptides were obtained experimentally using a parallel artificial membrane permeability assay (PAMPA) and showed a linear correlation with the computational results with R 2 ) 0.96. In general, the results support the hypothesis, already well established in the literature, that the ability to form internal hydrogen bonds is critical for passive membrane permeability and can be the distinguishing factor among closely related compounds, such as those studied here. However, we have found that the number of internal hydrogen bonds that can form in the membrane and the solvent-exposed polar surface area correlate more poorly with PAMPA permeability than our model, which quantitatively estimates the solvation free energy losses upon moving from high-dielectric water to the low-dielectric interior of a membrane.

The present study describes for the first time the species composition and toxicity of benthic cyanobacteria forming mats on the Nile River and irrigation canal sediments in Egypt. A total of 19 species of cyanobacteria were isolated from these mats during this study. The toxicity of the extracts of these species was investigated using Artemia salina assay, mouse bioassay and enzyme linked immunosorbent assay (ELISA). The results showed that all the 19 benthic species isolated from cyanobacterial mats, were toxic to A. salina. Two of these species, namely Calothrix parietina and Phormidium tenue, caused toxicity to mice with neurotoxic signs appeared within 12 h after injection. Whereas, five species showed hepatotoxic effects to mice within 6 h after injection. The results of ELISA showed that all the extracts which had hepatotoxic effects to mice, contained high levels of microcystins with concentrations ranging from 1.6 to 4.1 mg g K1 dry weight. HPLC analysis for heptotoxic extracts revealed that these extracts contained two peaks corresponding to microcystin-YR and -LR with different proportions. This study suggests that benthic species should be considered along with planktonic species during monitoring of toxic cyanobacteria in water sources, particularly the Nile river which is the main source of drinking water in Egypt. q

DNA gyrase is an attractive and well established target for the development of antibacterial agents. This bacterial enzyme, whose biological function is to control the topological state of DNA molecules, consists of two catalytic subunits; GyrA is responsible for DNA breakage and reunion, while the subunit GyrB contains the ATP-binding site. Coumarins and cyclothialidines are natural products that inhibit the ATPase activity of DNA gyrase by blocking the binding of ATP to subunit GyrB. The mechanism of action of these compounds was exhaustively characterized by biochemical methods and supported by protein crystallography. The abundance of crystallographic data on the N-terminal domain of GyrB in its complexes with various ligands has enabled the structure-based design of novel efficient chemotypes as inhibitors of the ATPase domain. This review summarizes the discovery of ATPase inhibitors of DNA gyrase B in the last decade and their development as potential antibacterial agents.