Ostreolysin enhances fruiting initiation in the oyster mushroom (Pleurotus ostreatus)

Fruiting initiation in mushrooms can be triggered by a variety of environmental and biochemical stimuli, including substances of natural or synthetic origin. In this work ostreolysin, a cytolytic protein specifically expressed during the formation of primordia and fruit bodies of Pleurotus ostreatus, was applied to nutrient media inoculated with mycelium of P. ostreatus, and its effects on mycelial growth and fructification of the mushroom studied. The addition of ostreolysin slightly inhibited the growth of mycelium, but strongly induced the formation of primordia, which appeared 10 d earlier than in control plates supplemented with bovine serum albumin or with the dissolving buffer alone. Moreover, ostreolysin stimulated the subsequent development of primordia into fruit bodies. However, direct involvement of this protein in the sporulation of the mushroom is unlikely, as it was also detected in large amounts in the non-sporulating strain of P. ostreatus

Characterization and cytotoxic activity of ribotoxin-like proteins from the edible mushroom Pleurotus eryngii

Ribotoxin-like proteins (RL-Ps) represent a novel specific ribonuclease family found in edible mushrooms and are able to inhibit protein synthesis. Here, we report the characterization and cytotoxic effects of four novel RL-Ps, named eryngitins, isolated from fruiting bodies of the king oyster mushroom (Pleurotus eryngii). These proteins induced formation of α-fragment from rabbit ribosomes, characteristic of their enzymatic action. The two 15 kDa eryngitins (3 and 4) are considerably more thermostable than the 21 kDa ones (1 and 2), however their overall structural features, as determined by far-UV CD spectrometry, are similar. Complete in vitro digestibility by pepsin-trypsin, and lack of cytotoxicity towards human HUVEC cells suggest low toxicity of eryngitins, if ingested. However, eryngitins exhibit cytotoxic action against insect Sf9 cells, suggesting their possible use in biotechnological applications as bioinsecticides. This cytotoxicity was not enhanced in the presence of cytolytic protein complexes based on aegerolysin proteins from Pleurotus mushrooms

Marine sponge-derived polymeric alkylpyridinium salts as a novel tumor chemotherapeutic targeting the cholinergic system in lung tumors.

Previous studies have shown that the cholinergic system plays a pivotal rule in small cell lung cancer (SCLC) cell growth through an autocrine loop that activates the nicotinic cholinergic receptor, which together with the activation of this receptor by nicotine links SCLC evolution with tobacco use. Non-small cell lung cancer (NSCLC) is the most common form of lung cancer and is also linked to tobacco use. Here we describe the presence of molecules of the cholinergic system in NSCLC samples and cell lines and investigate the implications of the cholinergic system in cell growth regulation. Cholinoacetyltransferase (ChAT), vesicular acetylcholine transporter (VAChT) and acetylcholinesterase (AChE) were observed in NSCLC tumor biopsies and in NSCLC cell lines. Polymeric alkylpyridinium salts (poly-APS) are AChE inhibitors isolated from the crude extract of the marine sponge, Reniera sarai. These metabolites were characterized as a mixture of two polymers of 3-octylpyridinium, including 29 and 99 monomeric units. Exposure of normal lung fibroblast and NSCLC cell lines to poly-APS revealed a selective cytotoxicity for cancer cells as compared to the normal fibroblast cell lines. FACS analysis indicated poly-APS induced apoptosis in NSCLC cells but not in normal lymphocytes. Non-toxic doses of poly-APS also potently reduced NSCLC cell-cell adhesion in suspension cultures. The limited toxicity of poly-APS on normal cells was confirmed by injection in the caudal vein of mice. No overt effects on health parameters, such as weight gain and physical behavior, were observed, and histological analysis of major organs did not reveal differences between the treated animals as compared to controls. These data demonstrate that NSCLC cells express cholinergic molecules that may be involved in cell growth regulation and that the cholinesterase inhibitor, poly-APS, shows selective toxicity toward NSCLC cells while having no apparent toxicity towards normal cells and tissue in vitro and in vivo

Spatial Distribution and Stability of Cholinesterase Inhibitory Protoberberine Alkaloids from Papaver setiferum

During a research program to identify new cholinesterase inhibitors of natural origin, two new 7,8-didehy-droprotoberberine alkaloids (1 and 2) and nine known compounds (3-11) were isolated from the capsules of the common ornamental poppy, Papaver setiferum (previously P. pseudo-orientale). Despite their reported instability, the 7,8-didehydroprotoberberines isolated herein appeared relatively stable, particularly as their trifluoroacetic acid salts. The spatial distributions of the isolated alkaloids were also analyzed using desorption electrospray ionization imaging mass spectrometry. The alkaloids were localized predominantly within the walls and vascular bundles of the capsules, with the highest relative abundances occurring in the lower half of the capsules toward the peduncle. The relative abundances of the alkaloids were also compared across plant development stages. Although most alkaloids did not show clear patterns in their concentration across development stages, the concentration of suspected oxidation products clearly spiked upon plant death. Finally, all isolated natural products were screened for inhibitory activities against a panel of cholinesterases, from both human and animal sources. These studies identified several competitive inhibitors of cholinesterases with potency in the low micromolar range (1-4, 6, 7), offering new lead compounds for the development of cholinesterase inhibitory drugs

New aspects of the relationship between acetylcholinesterase activity and cancer. I: Poly-Aps experiments.

Since the first \u201880s, we found that some tumor types, and in particular lung tumors present increase, or generally change in acetylcholinesterase activity. Acetylcholinesterase is an enzyme associated to the cholinergic signal system, whose classic role is to remove acetylcholine from the receptors. Nevertheless, it is also involved in cell-to-cell communication driving embryonic development and in the regulation of several cellular features, such as apoptosis and cell movements. The presence of molecules related to the cholinergic signal system in the healthy and carcinogenic lung tissues, raised the hypothesis that substances inhibiting or affecting the cholinergic signaling system could exert an anticancer action at least in these tissues. Cytotoxicity tests on immortalized and primary cell lines derived from lung tumor (NSCLC) showed an AChE inhibition-dependent selective reduction of cell viability, statistically significant. The same cells, exposed to non toxic AChE inhibitors exhibited a loss in the mitochondrial potential, characteristic of the early apoptotic events and showed positive response to the annexin V assay, and to the T-terminal assay, that are specific features of the apoptotic event. Moreover, three-dimensional cell cultures (spheroids) of tumor cells, on exposure to AChE inhibitors show a decrease in the membrane-linked oligosaccharides, that are responsible for the adhesivity of the metastatic cells. In this promising picture, the need emerges of further studies aimed at understanding the effects of AChE inhibition on the regulation of acetylcholine release and the effects of AChE inhibitors on the functioning of acetylcholine receptors

Multiple functions of the cholinesterase inhibiting polyalkylpyridinium salts extracted from the marine sponge, Haliclona sarai.

The interest on the Mediterranean sponge Haliclona sarai was raised some years ago by the fact that this sponge appears free from parasites and fouling organisms present in its environment. The study of such a feature was at the beginning due to the interest in finding new and efficient anti-fouling substances for applicative purposes. The characteristic was related to the expression of poly-alkylpyridinium salts (poly- APs), a mixture of two of 3-octylpyridinium polymers, including 29 and 99 monomeric units. The main effect of this compound was represented by the strong specific and non-toxic acetylcholinesterase inhibition in vitro. The substance was first tested for its effect on larval development and settling of incrusting organisms, such as Amphibalanus amphitrite. The experiments confirmed the ability of Poly-APs to prevent settlement of sessile organism, by impinging on the AChE activity. Acetylcholinesterase is an enzyme associated to the cholinergic signal system, but is also involved in cell-to-cell communication driving embryonic development and in the regulation of several cellular features, such as apoptosis and cell movements, and is present in some tumour cells and biopsies. Cytotoxicity tests on immortalized and primary cell lines derived from lung tumour (NSCLC) showed a poly-APS dose-dependent selective reduction of cell viability, statistically significant. The same cells, exposed to the poly-APS salts exhibited a loss in the mitochondrial potential, and positive response to apoptosis assays. What makes the poly-APS salts interesting as anticancer therapy adjuvant is that they, at the concentrations inducing apoptosis in tumour cells, seem to scarcely affect the viability of lymphocytes isolated from healthy patients. In this promising frame, the need emerges for the isolation of synthetic homologs of poly-APS molecules, in order to start a study for the therapeutical application of the drug. Key words: Lung Cancer, Acetylcholinesterase; Apoptosis; Cell Proliferation; Poly-APS 1 Introduction Nature has supplied several active anticancer agents (vinca alkaloids, anthracyclines, epipodophyllotoxin, and taxanes), which have significantly improved th