Sesquiterpene and Sorbicillinoid Glycosides from the Endophytic Fungus Trichoderma longibrachiatum EN-586 Derived from the Marine Red Alga Laurencia obtusa.

An unusual sesquiterpene glycoside trichoacorside A (1) and two novel sorbicillinoid glycosides sorbicillisides A (2) and B (3), together with a known compound sorbicillin (4), were isolated and identified from the culture extract of an endophytic fungus Trichoderma longibrachiatum EN-586, obtained from the marine red alga Laurencia obtusa. Trichoacorside A (1) is the first representative of a glucosamine-coupled acorane-type sesquiterpenoid. Their structures were elucidated based on detailed interpretation of NMR and mass spectroscopic data. The absolute configurations were determined by X-ray crystallographic analysis, chemical derivatization, and DP4+ probability analysis. The antimicrobial activities of compounds 1-4 against several human, aquatic, and plant pathogens were evaluated.

Recent Progress in Enhancing Fungal Disease Resistance in Ornamental Plants.

Fungal diseases pose a major threat to ornamental plants, with an increasing percentage of pathogen-driven host losses. In ornamental plants, management of the majority of fungal diseases primarily depends upon chemical control methods that are often non-specific. Host basal resistance, which is deficient in many ornamental plants, plays a key role in combating diseases. Despite their economic importance, conventional and molecular breeding approaches in ornamental plants to facilitate disease resistance are lagging, and this is predominantly due to their complex genomes, limited availability of gene pools, and degree of heterozygosity. Although genetic engineering in ornamental plants offers feasible methods to overcome the intrinsic barriers of classical breeding, achievements have mainly been reported only in regard to the modification of floral attributes in ornamentals. The unavailability of transformation protocols and candidate gene resources for several ornamental crops presents an obstacle for tackling the functional studies on disease resistance. Recently, multiomics technologies, in combination with genome editing tools, have provided shortcuts to examine the molecular and genetic regulatory mechanisms underlying fungal disease resistance, ultimately leading to the subsequent advances in the development of novel cultivars with desired fungal disease-resistant traits, in ornamental crops. Although fungal diseases constitute the majority of ornamental plant diseases, a comprehensive overview of this highly important fungal disease resistance seems to be insufficient in the field of ornamental horticulture. Hence, in this review, we highlight the representative mechanisms of the fungal infection-related resistance to pathogens in plants, with a focus on ornamental crops. Recent progress in molecular breeding, genetic engineering strategies, and RNAi technologies, such as HIGS and SIGS for the enhancement of fungal disease resistance in various important ornamental crops, is also described.

Chromenol Derivatives as Novel Antifungal Agents: Synthesis, In Silico and In Vitro Evaluation.

Herein we report the synthesis of some new 1H-1,2,4-triazole functionalized chromenols (3a-3n) via tandem reactions of 1-(alkyl/aryl)-2-(1H-1,2,4-triazole-1-yl) with salicylic aldehydes and the evaluation of their antifungal activity. In silico prediction of biological activity with computer program PASS indicate that the compounds have a high novelty compared to the known antifungal agents. We did not find any close analog among the over 580,000 pharmaceutical agents in the Cortellis Drug Discovery Intelligence database at the similarity cutoff of 70%. The evaluation of antifungal activity in vitro revealed that the highest activity was exhibited by compound 3k, followed by 3n. Their MIC values for different fungi were 22.1-184.2 and 71.3-199.8 µM, respectively. Twelve from fourteen tested compounds were more active than the reference drugs ketoconazole and bifonazole. The most sensitive fungus appeared to be Trichoderma viride, while Aspergillus fumigatus was the most resistant one. It was found that the presence of the 2-(tert-butyl)-2H-chromen-2-ol substituent on the 4th position of the triazole ring is very beneficial for antifungal activity. Molecular docking studies on C. albicans sterol 14α-demethylase (CYP51) and DNA topoisomerase IV were used to predict the mechanism of antifungal activities. According to the docking results, the inhibition of CYP51 is a putative mechanism of antifungal activity of the novel chromenol derivatives. We also showed that most active compounds have a low cytotoxicity, which allows us to consider them promising antifungal agents for the subsequent testing activity in in vivo assays.

miRNA Mediated Regulation and Interaction between Plants and Pathogens.

Plants have evolved diverse molecular mechanisms that enable them to respond to a wide range of pathogens. It has become clear that microRNAs, a class of short single-stranded RNA molecules that regulate gene expression at the transcriptional or post-translational level, play a crucial role in coordinating plant-pathogen interactions. Specifically, miRNAs have been shown to be involved in the regulation of phytohormone signals, reactive oxygen species, and NBS-LRR gene expression, thereby modulating the arms race between hosts and pathogens. Adding another level of complexity, it has recently been shown that specific lncRNAs (ceRNAs) can act as decoys that interact with and modulate the activity of miRNAs. Here we review recent findings regarding the roles of miRNA in plant defense, with a focus on the regulatory modes of miRNAs and their possible applications in breeding pathogen-resistance plants including crops and trees. Special emphasis is placed on discussing the role of miRNA in the arms race between hosts and pathogens, and the interaction between disease-related miRNAs and lncRNAs.

Trichothecenes in Food and Feed, Relevance to Human and Animal Health and Methods of Detection: A Systematic Review.

Trichothecene mycotoxins are sesquiterpenoid compounds primarily produced by fungi in taxonomical genera such as Fusarium, Myrothecium, Stachybotrys, Trichothecium, and others, under specific climatic conditions on a worldwide basis. Fusarium mold is a major plant pathogen and produces a number of trichothecene mycotoxins including deoxynivalenol (or vomitoxin), nivalenol, diacetoxyscirpenol, and T-2 toxin, HT-2 toxin. Monogastrics are sensitive to vomitoxin, while poultry and ruminants appear to be less sensitive to some trichothecenes through microbial metabolism of trichothecenes in the gastrointestinal tract. Trichothecene mycotoxins occur worldwide however both total concentrations and the particular mix of toxins present vary with environmental conditions. Proper agricultural practices such as avoiding late harvests, removing overwintered stubble from fields, and avoiding a corn/wheat rotation that favors Fusarium growth in residue can reduce trichothecene contamination of grains. Due to the vague nature of toxic effects attributed to low concentrations of trichothecenes, a solid link between low level exposure and a specific trichothecene is difficult to establish. Multiple factors, such as nutrition, management, and environmental conditions impact animal health and need to be evaluated with the knowledge of the mycotoxin and concentrations known to cause adverse health effects. Future research evaluating the impact of low-level exposure on livestock may clarify the potential impact on immunity. Trichothecenes are rapidly excreted from animals, and residues in edible tissues, milk, or eggs are likely negligible. In chronic exposures to trichothecenes, once the contaminated feed is removed and exposure stopped, animals generally have an excellent prognosis for recovery. This review shows the occurrence of trichothecenes in food and feed in 2011-2020 and their toxic effects and provides a summary of the discussions on the potential public health concerns specifically related to trichothecenes residues in foods associated with the exposure of farm animals to mycotoxin-contaminated feeds and impact to human health. Moreover, the article discusses the methods of their detection.

Fullerol C60(OH)24 Nanoparticles Affect Secondary Metabolite Profile of Important Foodborne Mycotoxigenic Fungi In Vitro.

Despite the efforts to control mycotoxin contamination worldwide, extensive contamination has been reported to occur in food and feed. The contamination is even more intense due to climate changes and different stressors. This study examined the impact of fullerol C60(OH)24 nanoparticles (FNP) (at 0, 1, 10, 100, and 1000 ng mL-1) on the secondary metabolite profile of the most relevant foodborne mycotoxigenic fungi from genera Aspergillus, Fusarium, Alternaria and Penicillium, during growth in vitro. Fungi were grown in liquid RPMI 1640 media for 72 h at 29 °C, and metabolites were investigated by the LC-MS/MS dilute and shoot multimycotoxin method. Exposure to FNP showed great potential in decreasing the concentrations of 35 secondary metabolites; the decreases were dependent on FNP concentration and fungal genus. These results are a relevant guide for future examination of fungi-FNP interactions in environmental conditions. The aim is to establish the exact mechanism of FNP action and determine the impact such interactions have on food and feed safety.

Surface Dielectric Barrier Discharge plasma: a suitable measure against fungal plant pathogens.

Fungal diseases seriously affect agricultural production and the food industry. Crop protection is usually achieved by synthetic fungicides, therefore more sustainable and innovative technologies are increasingly required. The atmospheric pressure low-temperature plasma is a novel suitable measure. We report on the effect of plasma treatment on phytopathogenic fungi causing quantitative and qualitative losses of products both in the field and postharvest. We focus our attention on the in vitro direct inhibitory effect of non-contact Surface Dielectric Barrier Discharge on conidia germination of Botrytis cinerea, Monilinia fructicola, Aspergillus carbonarius and Alternaria alternata. A few minutes of treatment was required to completely inactivate the fungi on an artificial medium. Morphological analysis of spores by Scanning Electron Microscopy suggests that the main mechanism is plasma etching due to Reactive Oxygen Species or UV radiation. Spectroscopic analysis of plasma generated in humid air gives the hint that the rotational temperature of gas should not play a relevant role being very close to room temperature. In vivo experiments on artificially inoculated cherry fruits demonstrated that inactivation of fungal spores by the direct inhibitory effect of plasma extend their shelf life. Pre-treatment of fruits before inoculation improve the resistance to infections maybe by activating defense responses in plant tissues.

Comparison of aquatic hyphomycetes communities between lotic and lentic environments in the Atlantic rain forest of Pernambuco, Northeast Brazil.

Riparian forests are important to aquatic ecosystems and produce large quantities of organic matter that are recycled by the microbial community that includes microscopic fungi. The aim of this study was to unveil and compare the diversity of aquatic hyphomycetes associated to submerged leaf litter of tropical lotic and lentic environments in the Atlantic Forest of Northeast Brazil. Six sampling events were carried out in six points of two study areas: Biological Reserve "Mata da Chuva" (MC) and Environmental Protection Area "Lagoa da Mata" (LM), in Pernambuco, Brazil. Twenty three taxa of hyphomycetes were identified resulting in 87 occurrences. In the lake LM, 13 taxa of hyphomycetes were identified with 34 occurrences and in the MC (stream), 20 taxa with 53 occurrences. Ten species were common to both areas. Diversity indices and fungal biomass (ergosterol) were mostly higher in the lotic system. The fungal community analysis did not show any structure regarding sampling periods or sampling points within an area, however the two areas are different. Although the turbulence of the water is considered important for the development of these aquatic fungi, it is possible to find a diverse community of hyphomycetes and considerable fungal biomass in the lentic environment.

Synthesis and mode of action studies of novel {2-(3-R-1H-1,2,4-triazol-5-yl)phenyl}amines to combat pathogenic fungi.

Due to their high specificity and efficacy, triazoles have become versatile antifungals to treat fungal infections in human healthcare and to control phytopathogenic fungi in agriculture. However, azole resistance is an emerging problem affecting human health as well as food security. Here we describe the synthesis of 10 novel {2-(3-R-1H-1,2,4-triazol-5-yl)phenyl}amines. Their structure was ascertained by liquid chromatography-mass spectrometry, 1 H and 13 C NMR, and elemental analysis data. Applying an in vitro growth assay, these triazoles show moderate to significant antifungal activity against the opportunistic pathogen Aspergillus niger, 12 fungi (Fusarium oxysporum, Fusarium fujikuroi, Colletotrichum higginsianum, Gaeumannomyces graminis, Colletotrichum coccodes, Claviceps purpurea, Alternaria alternata, Mucor indicus, Fusarium graminearum, Verticillium lecanii, Botrytis cinerea, Penicillium digitatum) and three oomycetes (Phytophtora infestans GL-1, P. infestans 4/91; R+ and 4/91; R-) in the concentration range from 1 to 50 µg/ml (0.003-2.1 µM). Frontier molecular orbital energies were determined to predict their genotoxic potential. Molecular docking calculations taking into account six common fungal enzymes point to 14α-demethylase (CYP51) and N-myristoyltransferase as the most probable fungal targets. With respect to effectiveness, structure-activity calculations revealed the strong enhancing impact of adamantyl residues. The shown nonmutagenicity in the Salmonella reverse-mutagenicity assay and no violations of drug-likeness parameters suggest the good bioavailability and attractive ecotoxicological profile of the studied triazoles.

Effect of quorum sensing molecules and natamycin on biofilms of Candida tropicalis and other yeasts isolated from industrial juice filtration membranes.

AIMS: Cells limit the cell number of dense biofilms by releasing self-inhibitory molecules. Here, we aim to assess the effectiveness of yeast quorum sensing (QS) molecules and the antifungal agent natamycin against yeast biofilms of strains commonly isolated from fruit juice ultrafiltration membranes. METHODS AND RESULTS: Yeast QS molecules, such as tyrosol, 2-phenylethanol and farnesol, were detected by solvent extraction and HS-SPME GC-MS in Candida tropicalis cultures. The effect of QS molecules on mono- and multispecies biofilms formed by Rhodotorula mucilaginosa, C. tropicalis, Candida krusei and Candida kefyr was evaluated by plate count and epifluorescence microscopy. Farnesol caused a decrease in cell number and disrupted mono- and multispecies yeast biofilms during adhesion (0·6 mmol l-1 ). 2-phenyl ethanol 1·2 mmol l-1 stimulated biofilm density and increased cell number in both mono- and multispecies biofilms, while tyrosol did not show effects when tested against C. tropicalis biofilms (0·05-1·2 mmol l-1 ). Natamycin caused a strong decrease in cell number and disruption of biofilm structure in C. tropicalis biofilms at high concentrations (0·3-1·2 mmol l-1 ). The combination of farnesol 0·6 mmol l-1 and natamycin at 0·01 mmol l-1 , the maximum concentration of natamycin accepted for direct addition into fruit juices, effectively reduced cell counts and disrupted the structure of C. tropicalis biofilms. CONCLUSION: Farnesol 0·6 mmol l-1 significantly increased the inhibition exerted by natamycin 0·01 mmol l-1 (~5 ppm) reducing biofilm development from juice on stainless steel surfaces. SIGNIFICANCE AND IMPACT OF THE STUDY: These results support the use of QS molecules as biofilm inhibitors in beverages and would certainly inspire the design of novel preservative and cleaning products for the food industry based on combinatory approaches.

Phenazine and 1-Undecene Producing Pseudomonas chlororaphis subsp. aurantiaca Strain KNU17Pc1 for Growth Promotion and Disease Suppression in Korean Maize Cultivars.

In this study, strain KNU17Pc1 was tested for its antifungal activity against Rhizoctonia solani AG-1(IA), which causes banded leaf and sheath blight (BLSB) of maize. KNU17Pc1 was tested further for its broad-spectrum antifungal activity and in vitro plant growth promoting (PGP) traits. In addition, the in vivo effects of KNU17Pc1 on reduction of BLSB severity and seedling growth promotion of two maize cultivars under greenhouse conditions were investigated. On the basis of multilocus sequence analysis (MLSA), KNU17Pc1 was confirmed as P. chlororaphis subsp. aurantiaca. The study revealed that KNU17Pc1 had strong in vitro antifungal activity and was effective toward all in vitro PGP traits except phosphate solubilization. In this study, for the first time, a strain of P. chlororaphis against Colletotrichum dematium, Colletotrichum gloeosporioides, Fusarium oxysporum f.sp. melonis, Fusarium subglutinans and Stemphylium lycopersici has been reported. Further biochemical studies showed that KNU17Pc1 was able to produce both types of phenazine derivatives, PCA and 2-OH-PCA. In addition, solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) analysis identified 13 volatile organic compounds (VOCs) in the TSB culture of KNU17Pc1, 1-undecene being the most abundant volatile. Moreover, for the first time, Octamethylcyclotetrasiloxan (D4), dimethyl disulfide, 2-methyl-1,3-butadiene and 1-undecene were detected in P. chlororaphis. Furthermore, this study reported for the first time the effectiveness of P. chlororaphis to control BLSB of maize. Hence, further studies are necessary to test the effectiveness of KNU17Pc1 under different environmental conditions so that it can be exploited further for biocontrol and plant growth promotion.

Expression of a wheat ß-1,3-glucanase in Pichia pastoris and its inhibitory effect on fungi commonly associated with wheat kernel.

ß-1,3-glucanases, the plant PR-2 family of pathogenesis-related (PR) proteins, can be constitutively expressed and induced in wheat crop to enhance its anti-fungal pathogen defense. This study aimed to investigate the inhibitory effect of wheat ß-1,3-glucanase on fungi most commonly associated with wheat kernel. A ß-1,3-glucanase from wheat was successfully expressed in Pichia pastoris X-33 and its biochemical and antifungal properties were characterized herein. The molecular weight of recombinant ß-1,3-glucanase is approximately 33 kDa. ß-1,3-glucanase displays optimal activity at pH 6.5, remaining relatively high at pH 5.5-8.0. The optimal reaction temperature of ß-1,3-glucanase is 50 °C, retaining approximately 84.0% residual activity after heat-treated at 50 °C for 1 h. The steady-state kinetic parameters of ß-1,3-glucanase against laminarin was determined and the Km and Vmax were 1.32 ±â€¯0.20 mg/ml and 96.4 ±â€¯4.4 U mg-1 protein, respectively. The inhibitory effect of purified ß-1,3-glucanase against the seven fungi commonly associated with wheat kernel was assessed in vitro. ß-1,3-glucanase exerted differential inhibitory effects on hyphal growth of Fusarium graminearum, Alternaria sp., A. glaucus, A. flavus, A. niger, and Penicillium sp. Spore formation and mycelial morphology of Alternaria sp., A. flavus, and A. niger were significantly affected by ß-1,3-glucanase (1U). The present results would help elucidate the mechanism underlying the inhibition of wheat ß-1,3-glucanases on pathogens.

Essential oils of Tahiti lemon and cinnamon bark in control of storage fungi and the physiological and sanitary quality of beans / Óleos essenciais de limão Taiti e canela em casca no controle de fungos de armazenamento e na qualidade fisiológica e sanitária de feijão

With the objective to evaluate the efficiency of essential oils of Citrus latifolia (Tahiti lemon) and Cinnamomum zeylanicum (cinnamon bark) in the control of plant pathogens Penicillium sp. and Aspergillus sp. and the quality of the bean seeds, two experiments were conducted. In the first one, the effect of essential oils of C. latifolia and C. zeylanicum was evaluated in vitro development of the fungi Penicillium sp. and Aspergillus sp. and, in the second one, the influence of essential oils on the physiological and sanitary quality of bean seeds. The variables mycelial growth, conidial germination and sporulation of Penicillium sp. and Aspergillus sp. were measured in the first experiment, while the seed germination test, first count of germination, germination speed index (GSI) and sanity test of bean seeds were measured in the second. The essential oil (EO) of C. zeylanicum was more efficient than C. latifolia in the control of Aspergillus sp. and Penicillium sp., but decreased the physiological quality of the beans seeds. The fungal diversity identified in the seed health test was composed by fungi of the genera Aspergillus, Penicillium, Cladosporium, Fusarium, Chaetomium and Rhizopus. The results indicate the potential of the use of these EOs in the seeds treatment.(AU)

Com o objetivo de avaliar a eficiência dos óleos essenciais de Citrus latifolia (limão taiti) e Cinnamomum zeylanicum (canela em casca) no controle dos fitopatógenos Penicillium sp. e Aspergillus sp. e na qualidade das sementes de feijão, foram conduzidos dois experimentos. No primeiro, avaliou-se o efeito dos óleos essenciais de C. latifolia e C. zeylanicum no desenvolvimento in vitro dos fungos Penicillium sp. e Aspergillus sp. e, no segundo, a influência dos óleos essenciais sobre a qualidade fisiológica e sanitária das sementes de feijão. As variáveis crescimento micelial, germinação de conídios e esporulação de Penicillium sp. e Aspergillus sp. foram aferidas no primeiro experimento, enquanto o teste de germinação de sementes, primeira contagem de germinação, índice de velocidade de germinação (IVG) e teste de sanidade de sementes de feijão foram aferidas no segundo. O óleo essencial (OE) de C. zeylanicum foi mais eficiente que C. latifolia no controle dos fungos Aspergillus sp. e Penicillium sp., mas diminuiu a qualidade fisiológica das sementes de feijão. A diversidade fúngica identificada no teste de sanidade de sementes foi composta por fungos dos gêneros Aspergillus, Penicillium, Cladosporium, Fusarium, Chaetomium e Rhizopus. Os resultados indicam o potencial do uso desses óleos essenciais no tratamento de sementes.(AU)

Synthesis, characterization, and evaluation of antifungal and antioxidant properties of cationic chitosan derivative via azide-alkyne click reaction.

In this work, quaternary ammonium group was introduced into chitosan backbone by cuprous-catalyzed azide-alkyne cycloaddition (CuAAC) to synthesize the cationic chitosan derivative bearing 1,2,3-triazole. The products were identified structurally by FTIR, 1H NMR spectroscopy, XRD, and elemental analysis. The water solubility of chitosan derivatives at different pH values was determined by a turbidity measurement. The antifungal properties of cationic chitosan derivatives against Botryis cinerea, Phomopsis asparagi, Fusarium oxysporum f. sp. niveum, and Fusarium oxysporum f. sp. cucumerium were evaluated using the radial growth assay. Besides, the antioxidant activities of them were also tested by superoxide-radical scavenging and reducing power assays. Compared to chitosan, cationic chitosan derivative bearing 1,2,3-triazole showed the good water solubility especially at alkaline condition, excellent antifungal action with over 70% inhibitory indices against tested fungi at 1.0 mg/mL, and enhanced antioxidant activity with complete scavenging efficiency against superoxide-radical at 1.6 mg/mL because of the introduction of 1,2,3-triazole and quaternary ammonium moieties. These excellent biological properties present a promising prospect for this chitosan derivative in antifungal and antioxidant biomaterials.

Biochars from olive mill waste have contrasting effects on plants, fungi and phytoparasitic nematodes.

Olive mill waste (OMW), a byproduct from the extraction of olive oil, causes serious environmental problems for its disposal, and extensive efforts have been made to find cost-effective solutions for its management. Biochars produced from OMW were applied as soil amendment and found in many cases to successfully increase plant productivity and suppress diseases. This work aims to characterize biochars obtained by pyrolysis of OMW at 300 °C to 1000 °C using 13C NMR spectroscopy, LC-ESI-Q-TOF-MS and SEM (Scanning Electron Microscopy). Chemical characterization revealed that biochar composition varied according to the increase of pyrolysis temperature (PT). Thermal treated materials showed a progressive reduction of alkyl C fractions coupled to the enrichment in aromatic C products. In addition, numerous compounds present in the organic feedstock (fatty acids, phenolic compounds, triterpene acids) reduced (PT = 300 °C) or completely disappeared (PT ≥ 500 °C) in biochars as compared to untreated OMW. PT also affected surface morphology of biochars by increasing porosity and heterogeneity of pore size. The effects of biochars extracts on the growth of different organisms (two plants, one nematode and four fungal species) were also evaluated. When tested on different living organisms, biochars and OMW showed opposite effects. The root growth of Lepidium sativum and Brassica rapa, as well as the survival of the nematode Meloidogyne incognita, were inhibited by the untreated material or biochar produced at 300 °C, but toxicity decreased at higher PTs. Conversely, growth of Aspergillus, Fusarium, Rhizoctonia and Trichoderma fungi was stimulated by organic feedstock, while being inhibited by thermally treated biochars. Our findings showed a pattern of association between specific biochar chemical traits and its biological effects that, once mechanistically explained and tested in field conditions, may lead to effective applications in agriculture.

Synthesis, characterization and antifungal efficacy of chitosan derivatives with triple quaternary ammonium groups.

A novel type of water soluble chitosan derivatives (TQCSPX) were synthesized including 3-aminopyridine (TQCSP1) and 3-Amino-4-methylpyridine (TQCSP2). The theoretical structures of TQCSPX were calculated by Gaussian 09 and confirmed by FT-IR, 1H NMR, 13C NMR, elemental analysis and XRD. The antifungal properties of TQCSPX against Phytophthora capsici (P. capsici), Rhizoctonia solani (R. solani), Fusarium oxysporum (F. oxysporum) and Fusarium solani (F. solani) were evaluated at concentrations ranging from 0.2mg/mL to 0.8mg/mL. Antifungal results indicated that the derivatives have significantly enhanced antifungal activity after quaternized compared with the original chitosan (CS). Moreover, TQCSP1 inhibited the growth of P. capsici with inhibitory indices of 91.94% at 0.8mg/mL. The experimental results demonstrated that the increasing number of the positive charge would improve the antifungal efficiency of chitosan, which may provide a novel direction for the development of fungicides.

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.

Antimicrobial potentials and phytochemical analysis of desert cotton (A. Javanica) and flax (L. Ustitatissimum).

The present study reveals antimicrobial potentials and phytochemical analysis of A. javanica and L. ustitatissimum. Phytochemical analysis indicated that the tested plants contained a substantial amount of flavonoids, terpenoids and steroids while saponins and tannins were absent in L. ustitatissimum, however, tannins were present in A. javanica. L. ustitatissimum contained maximum total phenolic content of 166.36mg/g in methylated spirit fraction while its ethyl acetate fraction contained highest quantity of flavonoids 27.6mg/g in case of Aerva javanica. Antimicrobial potentials of the subject plants revealed that L. ustitatissimum had maximum antibacterial activity (MIC=4.33µg/ml) while A. javanica was most effective against fungal strains (MIC=2.66µg/ml).

Damage to Trichothecium roseum caused by sodium silicate is independent from pH.

Trichothecium roseum is one of the most important postharvest pathogens in arid and semiarid regions. Sodium silicate (NaSi) and environmental pH have significant inhibitory effects on fungal growth. However, no study has addressed the relationship of NaSi and pH in combination and the effects on T. roseum. In this work, we showed that spore germination, germ tube elongation, and mycelial growth of T. roseum were significantly inhibited by various NaSi concentrations, which had corresponding increasing pHs. Furthermore, these NaSi solutions showed a much greater impact than did pH treatments alone. The pathogenicity of NaSi-treated conidia on a model assay (conidia-inoculated apple fruit) was dramatically reduced, whereas no changes of pathogenicity were evident for the corresponding pH (various sodium hydroxide (NaOH) solutions) treatments. Fluorescent microscopy, using propidium iodide staining, showed damage of the plasma membranes of T. roseum conidia treated with both NaSi and NaOH, although the damage was more severe with NaSi. Leakage of proteins and sugars was significantly higher in NaSi-treated and NaOH-treated conidia than in untreated controls. In addition, serious damage was observed in the conidia exposed to NaSi for longer periods of time. Ultrastructural observations showed that treatment with either NaSi or NaOH caused a plasmolysis state and disorganized organelles. Taken together the results show that NaSi has inhibitory effects on T. roseum and that the inherent higher pH of NaSi solutions of higher concentrations simply acts as an enhancer of the inhibitory effects of NaSi.

Facile heterocyclic synthesis and antimicrobial activity of polysubstituted and condensed pyrazolopyranopyrimidine and pyrazolopyranotriazine derivatives.

Reaction of 6-amino-3-methyl-4-(substituted phenyl)-1,4- dihydropyrano[2,3-c]pyrazole-5-carbonitrile (1) with triethylorthoformate followed by treatment with hydrazine hydrate, formic acid, acetic acid, phenylisocyanate, ammonium thiocyanate and formamide afforded the corresponding pyranopyrimidine derivatives 2-6. Cyclocondensation of 1 with cyclohexanone afforded pyrazolopyranoquinoline 7. One-pot process of diazotation and de-diazochlorination of 1 afforded pyrazolopyranotriazine derivative 8, which upon treatment with secondary amines afforded 9 and 10a- c. Condensation of 2 with aromatic aldehyde gave the corresponding Schiff bases 11a,b, the oxidative cyclization of the hydrazone with appropriate oxidant afforded 11-(4- fluorophenyl))- 2-(4-substituted phenyl)-10-methyl-8,11-dihydropyrazolo-[ 4',3':5,6]pyrano[3,2-e][1,2,4]triazolo[1,5-c]pyrimidines (12a,b). Structures of the synthesized compounds were confirmed by spectral data and elemental analysis. All synthesized compounds were evaluated for antibacterial and antifungal activities compared to norfloxacin and fluconazole as standard drugs. Compounds 9, 10c, 12a and 15 were found to be the most potent antibacterial agents, with activity equal to that of norfloxacin. On the other hand, compound 5 exhibited higher antifungal activity compared to fluconazole.