Antimicrobial activity of pomegranate peel extracts as affected by cultivar.

BACKGROUND: Some studies have reported that different parts of the pomegranate fruit, especially the peel, may act as potential antimicrobial agents and thus might be proposed as a safe natural alternative to synthetic antimicrobial agents. The high tannin content, especially punicalagin, found in pomegranate extracts, has been reported as the main compound responsible for such antimicrobial activity. Because the pomegranate peel chemical composition may vary with the type of cultivar (sweet, sour-sweet and sour), pomegranates may also differ with respect to their antimicrobial capacity. RESULTS: The extract from PTO8 pomegranate cultivar peel had the highest antimicrobial activity, as well as the highest punicalagins (α and ß) and ellagic acid concentrations. In the results obtained from both antibacterial and antifungal activity studies, the sour-sweet pomegranate cultivar PTO8 showed the best antimicrobial activity, and the highest ellagic acid concentrations. CONCLUSION: The results of the present study suggest that ellagic acid content has a significant influence on the antimicrobial activity of the pomegranate extracts investigated. The pomegranate peel of the PTO8 cultivar is a good source of antifungal and antibacterial compounds, and may represent an alternative to antimicrobial agents of synthetic origin. © 2016 Society of Chemical Industry.

Responsiveness of entomopathogenic fungi to menadione-induced oxidative stress.

Entomopathogenic fungi are predisposed to ROS induced by heat and UV-A radiation when outside the insect host. When inside the host, they are subject to phagocytic cells that generate ROS to eliminate invading pathogens. The oxidative stress tolerance of the entomopathogenic fungi Aschersonia aleyrodis (ARSEF 430 and 10276), Aschersonia placenta (ARSEF 7637), Beauveria bassiana (ARSEF 252), Isaria fumosorosea (ARSEF 3889), Lecanicillium aphanocladii (ARSEF 6433), Metarhizium acridum (ARSEF 324), Metarhizium anisopliae (ARSEF 5749), Metarhizium brunneum (ARSEF 1187 and ARSEF 5626), Metarhizium robertsii (ARSEF 2575), Tolypocladium cylindrosporum (ARSEF 3392), Tolypocladium inflatum (ARSEF 4877), and Simplicillium lanosoniveum (ARSEF 6430 and ARSEF 6651) was studied based on conidial germination on a medium supplemented with menadione. Conidial germination was evaluated 24 h after inoculation on potato dextrose agar (PDA) (control) or PDA supplemented with menadione. The two Aschersonia species (ARSEF 430, 7637, and 10276) were the most susceptible fungi, followed by the two Tolypocladium species (ARSEF 3392 and 4877) and the M. acridum (ARSEF 324). Metarhizium brunneum (ARSEF 5626) and M. anisopliae (ARSEF 5749) were the most tolerant isolates with MIC 0.28 mM. All fungal isolates, except ARSEF 5626 and ARSEF 5749, were not able to germinate at 0.20 mM.

A detailed comparative study between chemical and bioactive properties of Ganoderma lucidum from different origins.

A detailed comparative study on chemical and bioactive properties of wild and cultivated Ganoderma lucidum from Serbia (GS) and China (GCN) was performed. This species was chosen because of its worldwide use as medicinal mushroom. Higher amounts of sugars were found in GS, while higher amounts of organic acids were recorded in GCN. Unsaturated fatty acids predominated over saturated fatty acids. GCN revealed higher antioxidant activity, while GS exhibited inhibitory potential against human breast and cervical carcinoma cell lines. No cytotoxicity in non-tumour liver primary cell culture was observed for the different samples. Both samples possessed antibacterial and antifungal activities, in some cases even better than the standard antimicrobial drugs. This is the first study reporting a comparison of chemical compounds and bioactivity of G. lucidum samples from different origins.

The ectopic expression of a pectin methyl esterase inhibitor increases pectin methyl esterification and limits fungal diseases in wheat.

Cell wall pectin methyl esterification can influence plant resistance because highly methyl-esterified pectin can be less susceptible to the hydrolysis by pectic enzymes such as fungal endopolygalacturonases (PG). Pectin is secreted into the cell wall in a highly methyl-esterified form and, here, is de-methyl esterified by pectin methyl esterase (PME). The activity of PME is controlled by specific protein inhibitors called PMEI; consequently, an increased inhibition of PME by PMEI might modify the pectin methyl esterification. In order to test the possibility of improving wheat resistance by modifying the methyl esterification of pectin cell wall, we have produced durum wheat transgenic lines expressing the PMEI from Actinidia chinensis (AcPMEI). The expression of AcPMEI endows wheat with a reduced endogenous PME activity, and transgenic lines expressing a high level of the inhibitor showed a significant increase in the degree of methyl esterification. These lines showed a significant reduction of disease symptoms caused by the fungal pathogens Bipolaris sorokiniana or Fusarium graminearum. This increased resistance was related to the impaired ability of these fungal pathogens to grow on methyl-esterified pectin and to a reduced activity of the fungal PG to hydrolyze methyl-esterified pectin. In addition to their importance for wheat improvement, these results highlight the primary role of pectin despite its low content in the wheat cell wall.

Chemical composition and antifungal activity of essential oil from Cicuta virosa L. var. latisecta Celak.

The essential oil extracted from the fruits of Cicuta virosa L. var. latisecta Celak was tested in vitro and in vivo against four foodborne fungi, Aspergillus flavus, Aspergillus oryzae, Aspergillus niger, and Alternaria alternata. Forty-five different components accounting for 98.4% of the total oil composition were identified by gas chromatography-mass spectrometry. The major components were γ-terpinene (40.92%), p-cymene (27.93%), and cumin aldehyde (21.20%). Antifungal activity was tested by the poisoned food technique against the four fungi. Minimum inhibitory concentration against the fungi was 5 µL/mL and percentage inhibition of mycelial growth was determined at day 9. The essential oil had a strong inhibitory effect on spore production and germination in all tested fungi proportional to concentration. The oil exhibited noticeable inhibition on dry mycelium weight and synthesis of aflatoxin B1 (AFB1) by A. flavus, completely inhibiting AFB(1) production at 4 µL/mL. The effect of the essential oil on inhibition of decay development in cherry tomatoes was tested in vivo by exposing inoculated and control fruit to essential oil vapor at a concentration of 200 µL/mL. Results indicated that the essential oil from C. virosa var. latisecta (CVEO) has potential as a preservative to control food spoilage.

Effects of metals on growth and sporulation of aquatic fungi.

Aquatic hyphomycetes are a relevant group of fungi that play a crucial role as intermediaries between plant detritus and invertebrates in clean or metal-polluted streams. In this study, we investigated the effects of Zn, Cu, Ni, and Cd on the growth and sporulation of several aquatic hyphomycete species. Effects of these metals on growth were assessed in solid and liquid media with different compositions [1% malt extract (ME) and a mineral medium supplemented with vitamins and 2% glucose (MK)], and fungal sensitivity to metals was compared. The exposure to Zn or Cd inhibited the sporulation of Heliscus submersus and Tricladium chaetocladium, with these effects being stronger in the latter species. In solid medium, mydelial growth was linear, and, in most cases, metals negatively affected fungal growth. The sensitivity of aquatic hyphomycetes to metals, assessed as the metal concentration inhibiting biomass production in 50% (EC(50)), showed that Ypsilina graminea and Varicosporium elodeae were the most resistant species to Zn, while Alatospora acuminata, H. submersus, and Flagellospora curta appeared to be the most resistant fungus to Cu. Generally, lower toxicity of Zn or Cu than Ni or Cd was found. However, EC(50) values were about 20 times higher in solid than in liquid medium. Changes in nutrient supplies to fungi affected metal toxicity, as shown by higher EC(50) values in MK than ME. Complementarily, fungal tolerance to metals varied with fungal species as well as metal type.

Phytoremediation of petroleum-polluted soils: application of Polygonum aviculare and its root-associated (penetrated) fungal strains for bioremediation of petroleum-polluted soils.

Petroleum-polluted soils are a common disaster in many countries. Bioremediation of oil contamination in soils is based on the stimulation of petroleum-hydrocarbon-degrading fungal and microbial communities. A field study was conducted in a petroleum-contaminated site to find petroleum-resistant plants and their root-associated fungal strains for use in bioremediation of petroleum-polluted soils. Results and observations showed that the amounts of petroleum pollution in nonvegetated soils were several times higher than in vegetated soils. Plants collected from petroleum-polluted areas were identified using morphological characters. Results indicated that seven plant species were growing on the contaminated sites: Alhaji cameleron L. (Fabaceae), Amaranthus retroflexus L. var. retroflexus (Amaranthaceae), Convolvulus arvensis L. (Convolvulaceae), Chrozophora hierosolymitana Spreg. (Euphorbiaceae), Noea mucronata L. (Boraginaceae), Poa sp. (Poaceae), and Polygonum aviculare L. (Polygonaceae). The root-associated fungi of each plant were determined and results showed the presence of 11 species that associated with and also penetrated the roots of plants growing in the polluted areas. Altenaria sp. was common to all of the plants and the others had species-specific distribution within the plants. The largest numbers of fungal species (six) were determined for P. aviculare and Poa sp. in polluted areas. However, the variation of fungal strains in the plants collected from petroleum-polluted areas was greater than for nonpolluted ones. Culture of fungi in oil-contaminated media showed that all the studied fungi were resistant to low petroleum pollution (1% v/v) and a few species, especially Fusarium species, showed resistance to higher petroleum pollution (10% v/v) and may be suitable for bioremediation in highly polluted areas. Bioremediation tests with P. aviculare, with and without fungal strains, showed that application of both the plant and its root-associated fungal strains was more effective than of the plant and fungi separately, and Fusarium species were the most effective. Results indicated that fungal strains had the main role in bioremediation of petroleum-polluted soils, but plant roots enhanced the process.

Characterisation of uranium(VI) sorption by two environmental fungal species using gamma spectrometry.

Uranium(VI) sorption by two highly uranium-resistant air-borne fungi in a low-pH medium was measured by means of gamma spectrometry. Growth kinetics and stoichiometry of the two fungal species were also studied. Results show acceptable growth rates in synthetic medium with glucose and ammonia as carbon and nitrogen sources, respectively. Typical oxidative metabolism of carbohydrates was found. In vivo uptake of the radionuclide was negligible, but biosorption dry biomass presented a remarkable performance. The fungal strains showed potential for use in bioremediation.

[Detection of fungal metabolites showing toxic activity through Artemia salina bioassay]. / Detección de metabolitos fúngicos con actividad tóxica mediante bioensayo sobre Artemia salina.

The aim of this study was to detect toxic metabolites from fungi contaminating food and medicinal herbs by applying the toxicity assay to Artemia salina. According to toxicity percentages, the extracts were classified as nontoxic (NT), slightly toxic (ST), toxic (T) and highly toxic (HT). Those classified as T and HT were assayed for mycotoxins. Only 6 out of 71 strains were found to be T (8.5%) for A. salina. Penicillium brevicompactum Dierckx, isolated from sausages, was found to be HT, mainly due to the presence of ochratoxin A and two other unidentified metabolites.

Cytotoxic activities of ethyl acetate extract and a metabolite from a Monocillium species.

The ethyl acetate soluble fraction of a cultural broth of a Monocillium species afforded the isolation of 5-hydroxymethylfurfural. Both the extract and 5-hydroxymethylfurfural showed significant cytotoxic activities in a brine shrimp bioassay and the LC(50) values were found to be 14.96 microg/mL and 23.71 microg/mL, respectively.

[Lovastatin effect on ergosterol production and growth of Tolypocladium inflatum 106]. / Vliianie lovastatina na rost i obrazovanie érgosterola kul'turoi Tolypocladium inflatum 106.

The effect of lovastatin on Tolypocladium inflatum 106 was studied. The strain was shown to be highly sensitive to lovastatin when its MIC was determined by the agar diffusion method and under submerged conditions that was considered possible to use the strain as a test culture in screening of new natural compounds with hypolipidemic action and to study its specificity. It was demonstrated that the effect of lovastatin on ergosterol synthesis in T. inflatum 106 was of specific dose-dependent polymodal nature.

[Screening of natural compounds with hypolipidemic activity]. / Skrining prirodnykh soedinenii s gipolipidemicheskoi aktivnost'iu.

In the screening programme for natural hypolipidemic compounds 702 strains of soil microorganisms were tested and 25 of them were selected because of their ability to produce compounds inhibiting sterol synthesis in Hep G2 hepatoma cells. The compounds were estimated in the microbiological model with Tolypocladium inflatum 106 as the test microbe. The 2nd stage of the screening resulted in isolation of 13 strains producing compounds with high hypolipidemic activity, analogous to or higher than the activity of lovastatin in the experimental models.

Screening of entomopathogenic Deuteromycetes for activities on targets involved in degenerative diseases of the central nervous system.

A selection of 32 fungal strains, belonging to 8 genera of entomopathogenic Deuteromycetes collected in various provinces of China, were screened for activities on targets involved in degenerative diseases of the central nervous system. The strains were grown under various fermentation conditions, and a total of 256 different extracts were obtained. The bioassays included functional screens for NMDA antagonistic activity in stably transfected fibroblasts, for neuritogenic activities in PC-12 cells, and tests for MAO inhibitory and radical scavenging properties. Several extracts with promising activities were identified. Some Paecilomyces extracts induced pronounced axonal-like outgrowths in PC-12 cells. In Paecilomyces militaris RCEF 0095, the neuritogenic activity could be linked to yellow pigments. Three Beauveria and Paecilomyces strains showed radical scavenging properties, which could be localized in the extract by a bioautographic assay on TLC. An extract obtained from the mycelium of Paecilomyces tenuipes RCEF 0275 showed moderate MAO inhibitory activity, whereas extracts of Sporothrix chondracris RCEF 0187 antagonized NMDA receptor mediated cell toxicity.

Epicoccamide, a novel secondary metabolite from a jellyfish-derived culture of Epicoccum purpurascens.

From the inner tissue of the jellyfish Aurelia aurita a marine strain of the fungus Epicoccum purpurascens was obtained. After mass cultivation the fungus was investigated for its secondary metabolite content and found to contain the new, and most unusual tetramic acid derivative, epicoccamide (1). Epicoccamide is quite unusual since it is composed of three biosynthetically distinct subunits; glycosidic, fatty acid and tetramic acid (amino acid). The structure of the new compound was elucidated using spectroscopic methods, mainly 1D and 2D NMR, ESI-MS, and chemical degradations.

A study on the microbiota from olive-mill wastewater (OMW) disposal lagoons, with emphasis on filamentous fungi and their biodegradative potential.

The microbial composition of olive mill wastewater (OMW) from four disposal ponds has been studied. Such OMW samples contained a variable (but high) number of bacteria, yeasts and molds. Among the latest, members of twelve different genera (Acremonium, Alternaria, Aspergillus, Chalara, Fusarium, Lecytophora, Paecilomyces, Penicillium, Phoma, Phycomyces, Rhinocladiella and Scopulariopsis) were found. Members of five genera (Chalara, Fusarium, Paecilomyces, Penicillium and Scopulariopsis) were widely distributed, and they were able to grow efficiently in undiluted OMW as a sole source of nutrients. Strains of Fusarium, Paecilomyces, Penicillium and Scopulariopsis showed a marked capacity for OMW detoxification, depleting its antibacterial activity almost completely.

Impact of phosphate-solubilizing fungi on the yield and phosphorus-uptake by wheat and faba bean plants.

Three fungal isolates (phosphate-dissolvers), Aspergillus niger, A. fumigatus and Penicillium pinophilum were isolated from the rhizosphere of different plants grown in Ismailia and South Sinai Governorates. They effectively solubilized rock phosphate or tricalcium phosphate in Pikovskaya's liquid medium. In pot and column experiments, they significantly reduced pH and increased available phosphorus in the soil treated with either rock phosphate or superphosphate. The yield components of wheat and faba bean plants increased as a result of soil inoculation with the isolated fungi. Penicillium pinophilum was the most efficient isolate. It increased the yield of wheat grains by 28.9 and 32.8% in the soil treated with rock phosphate and superphosphate, respectively. Similarly, it increased the production of faba bean seeds by 14.7 and 29.4% with the same treatments. The uptake of phosphorus by both crops significantly increased due to inoculation of the soil with the tested fungi.

Argifin, a new chitinase inhibitor, produced by Gliocladium sp. FTD-0668. I. Taxonomy, fermentation, and biological activities.

A new chitinase inhibitor, named argifin, was isolated from the cultured broth of a fungal strain FTD-0668. The strain was identified as Gliocladium sp. from morphological characteristics. The IC50 value of argifin against Lucilia cuprina chitinase was 3.7 microM. Argifin arrested the moult of cockroach larvae upon injection into the ventral abdominal part.

Roselipins, inhibitors of diacylglycerol acyltransferase, produced by Gliocladium roseum KF-1040.

Gliocladium roseum KF-1040, a marine isolate, was found to produce a series of new inhibitors of diacylglycerol acyltransferase (DGAT). Four active compounds, designated roselipins 1A, 1B, 2A and 2B, were isolated from the fermentation broth of the producing strain by solvent extraction, ODS column chromatography and preparative HPLC. The highest production of roselipins was observed when cultured in the medium containing natural sea water. Roselipins inhibit DGAT activity with IC50 values of 15 approximately 22 microM in an enzyme assay system using rat liver microsomes.

Effect of the raw extract of Arthrinium strains (Hyphomycetes, Dematiaceae) on the growth of pathogenic bacteria in poultry feed.

Poultry feed contains a significant reservoir of bacteria and is a possible source of Salmonella typhimurium, Staphylococcus aureus and Escherichia coli, which can potentially infect farm animals and humans. The objective of this study was to determine whether the extract obtained from the culture of some Arthrinium species was able to inhibit the growth of these bacteria. The results obtained showed that the raw extracts of Arthrinium aureum, Arthrinium serenensis and Arthrinium phaeospermum inhibited the growth of Escherichia coli in poultry feed. In some cases the percentage inhibition of the growth of Escherichia coli was > 80%. With the raw extract of Arthrinium in poultry feed, the rate of growth of S. typhimurium fell to between 50% and 80%. The raw extract of A. serenensis had the lowest inhibitory activity. S. aureus counts were not affected by any Arthrinium raw extracts.