Screening for decolorizing basidiomycetes in Mexico

A survey to isolate native white rot basidiomycetes from Northeast Mexico was conducted in the forests of the Sierra Madre Oriental in the state of Nuevo León. A total of 92 isolates from at least 20 different genera, were screened on Bran-Flakes solid plate cultures for the production of ligninolytic oxidases and/or peroxidases with guaiacol and o-anisidine as substrates; their lignin depolymerizing potential using the polymeric dye Poly R 478; their ability to decolorize anthraquinonic (Remazol Brilliant Blue Reactive), azo (Acid Red 44) and triphenylmethane (Crystal Violet) dyes. Among all fungi tested, 15 isolates showed extensive decolorization of the three dyes within a week and gave a positive reaction in guaiacol and o-anisidine tests. Nine of them were also efficient degraders of Poly R-478. Two isolates (CS5 and CU1) showed decolorization of all dyes within 5 days, comparing favorably with reference strains of P. chrysosporium, Pleurotus ostreatus, and Bjerkandera adusta. Decolorization was associated with laccase activity in both isolates and reached 90% or more for all dyes within 24 h in 8-day-old liquid cultures. The coupling of pairs 2,4-dichlorophenol + 4-aminoantipyrine and 3-dimethylaminobenzoic acid + 3-methyl-2-benzothiazolinone hydrazone, strongly suggest that the laccases of both strains correspond to those considered of high redox potential. These strains are considered good candidates for bioremediation of dye polluted effluents due to their ligninolytic potential and decolorizing performance.     

Screening of Brazilian basidiomycetes for antimicrobial activity

A total of 103 isolates of basidiomycetes, representing 84 species from different Brazilian ecosystems, were evaluated for their antifungal and antibacterial activity in a panel of pathogenic and non-pathogenic microorganisms. Tissue plugs of the fruiting bodies were cultivated in liquid media and the whole culture extracted with ethyl acetate. Crude extracts from Agaricus cf. nigrecentulus, Agrocybe perfecta, Climacodon pulcherrimus, Gloeoporus thelephoroides, Hexagonia hydnoides, Irpex lacteus, Leucoagaricus cf. cinereus, Marasmius cf. bellus, Marasmius sp., Nothopanus hygrophanus, Oudemansiella canarii, Pycnoporus sanguineus, Phellinus sp., and Tyromyces duracinus presented significant activity against one or more of the target microorganisms. Eight isolates were active only against bacteria while three inhibited exclusively the growth of fungi. Two extracts presented wide antimicrobial spectrum and were active against both fungi and bacteria. Differences in the bioactivity of extracts obtained from isolates from the same species were observed.     

Design,synthesis and evaluation of carbazole derivatives as potential antimicrobial agents

Five series of novel carbazole derivatives containing an aminoguanidine, dihydrotriazine, thiosemicarbazide, semicarbazide or isonicotinic moiety were designed, synthesised and evaluated for their antimicrobial activities. Most of the compounds exhibited potent inhibitory activities towards different bacterial strains (including one multidrug-resistant clinical isolate) and one fungal strain with minimum inhibitory concentrations (MICs) between 0.5 and 16 µg/ml. Compounds 8f and 9d showed the most potent inhibitory activities (MICs of 0.5–2 µg/ml). Furthermore, compounds 8b, 8d, 8f, 8k, 9b and 9e with antimicrobial activities were not cytotoxic to human gastric cancer cell lines (SGC-7901 and AGS) or a normal human liver cell line (L-02). Structure–activity relationship analyses and docking studies implicated the dihydrotriazine group in increasing the antimicrobial potency and reducing the toxicity of the carbazole compounds. In vitro enzyme activity assays suggested that compound 8f binding to dihydrofolate reductase might account for the antimicrobial effect.     

Screening of Bifidobacterium strains isolated from human faeces for antagonistic activities against potentially bacterial pathogens

As probiotic bacteria, strains belonging to the genus Bifidobacterium colonise the gastro-intestinal tract of humans and animals at the time of birth, and they are found in young as well as in adult individuals in great numbers. Moreover, they can interact with the development of enteric infections by the production of antimicrobial metabolites. In this work 281 strains of bifidobacteria were anaerobically isolated from human faecal samples, supplied by volunteers of different ages (youngs, adults, elders), and preliminarly described by microscopic observation. All strains were screened by the fructose 6-phosphate phosphoketolase (F6PPK) test in order to confirm their classification within the genus Bifidobacterium. Selected strains were used to evaluate their antagonistic activities against Escherichia coli, Salmonella thyphimurium, Staphylococcus lentus, Enterococcus faecalis, Acinetobacter calcoaceticus, Sphingomonas paucimobilis, Listeria monocytogenes, Yersinia enterocolitica, Bacillus cereus, Clostridium sporogenes. Experiments were performed in vitro by different methods based on the observation of growth inhibition in Petri dishes. The strains that showed the highest inhibiting activities were compared by SDS-PAGE for total cell proteins, using type strains of human origin as references. Representative isolates were metabolically characterised by the BIOLOG system; a specific database was created with strains obtained from our collection and a statistical evaluation for metabolic patterns was carried out.     

Antibacterial and antifungal activities of teucrium royleanum (Labiatea)

The crude methanolic extract and subsequent fractions of Teucrium royleanum (Labiatea) were screened for antibacterial and antifungal activities. Against tested pathogens, crude extract and subsequent fractions demonstrated moderate to excellent antibacterial activities. Highest antibacterial activity was displayed by the ethyl acetate fraction against S. typhi (100%), against E.coli (76.7%) and against P. aerugenosa (70.8%) followed by the chloroform fraction against S. typhi (85.7%). Similarly, the crude extract and its subsequent fractions showed mild to excellent activities in the antifungal bioassay with maximum antifungal activity against M. canis (87%) by the chloroform fraction followed by the ethyl acetate (71%) and n-butanol (70%) fractions.     

Degradation of proteinaceous substrates by xylotrophic basidiomycetes

The ability of various xylotrophs to produce extracellular proteolytic enzymes has been studied, with emphasis on medium-related factors regulating their secretion. Direct measurement of proteolytic activity in the culture liquid and postelectrophoresis determination of protease activity in polyacrylamide gel copolymerized with gelatin demonstrated that the secreted enzymes are quantitatively and qualitatively diverse. Activity levels of extracellular proteolytic enzymes strongly depend on pH and contents of protein and carbohydrate in the medium. All secreted proteases notably differed in molecular weight (of 51 kDa or higher and in excess of 95 kDa) and belonged mostly to two classes of proteolytic enzymes (serine proteases and metalloproteinases).     

Ligninolytic activity of tropical rainforest basidiomycetes

A total of 116 strains of Brazilian tropical rainforest basidiomycetes were evaluated in terms of their ability to oxidize the dye rhemazol brilliant blue R (RBBR) and guaiacol. Laccase and peroxidase activities were detected by the drop test using solutions of α-naphthol and pyrogallol, respectively. RBBR and guaiacol oxidation occurred in 96.6 and 87.1% of the strains tested, respectively. One hundred strains oxidized both substrates. In the drop test, most strains presented laccase (96.6%) and peroxidase (92.2%) activity. The quick screening method used here can be useful to identify ligninolytic fungal strains to be used in various biotechnological applications. This revised version was published online in November 2006 with corrections to the Cover Date.     

An efficient synthesis of bis(indolyl)methanes and evaluation of their antimicrobial activities

A versatile and efficient method has been developed for the synthesis of bis(indolyl)methanes by using aluminium triflate (0.5 mol%) as a novel catalyst. Further, some of the synthesized compounds were evaluated for their efficacy as antibacterial and antifungal activities. Most of the compounds have shown moderate to good inhibitory activity.     

Distinct antimicrobial activities in aphid galls on Pistacia atlantica

Gall-formers are parasitic organisms that manipulate plant traits for their own benefit. Galls have been shown to protect their inhabitants from natural enemies such as predators and parasitoids by various chemical and mechanical means. Much less attention, however, has been given to the possibility of defense against microbial pathogens in the humid and nutrient-rich gall environment. We found that the large, cauliflower-shaped, galls induced by the aphid Slavum wertheimae on buds of Pistacia atlantica trees express antibacterial and antifungal activities distinct from those found in leaves. Antibacterial activity was especially profound against Bacillus spp (a genus of many known insect pathogen) and against Pseudomonas aeruginosa (a known plant pathogen). Antifungal activity was also demonstrated against multiple filamentous fungi. Our results provide evidence for the protective antimicrobial role of galls. This remarkable antibacterial and antifungal activity in the galls of S. wertheimae may be of agricultural and pharmaceutical value.     

Screening of free-living rhizospheric bacteria for their multiple plant growth promoting activities

Plant growth promoting rhizobacteria (PGPR) are known to influence plant growth by various direct or indirect mechanisms. In search of efficient PGPR strains with multiple activities, a total of 72 bacterial isolates belonging to Azotobacter, fluorescent Pseudomonas, Mesorhizobium and Bacillus were isolated from different rhizospheric soil and plant root nodules in the vicinity of Aligarh. These test isolates were biochemically characterized. These isolates were screened in vitro for their plant growth promoting traits like production of indoleacetic acid (IAA), ammonia (NH(3)), hydrogen cyanide (HCN), siderophore, phosphate solubilization and antifungal activity. More than 80% of the isolates of Azotobacter, fluorescent Pseudomonas and Mesorhizobium ciceri produced IAA, whereas only 20% of Bacillus isolates was IAA producer. Solubilization of phosphate was commonly detected in the isolates of Bacillus (80%) followed by Azotobacter (74.47%), Pseudomonas (55.56%) and Mesorhizobium (16.67%). All test isolates could produce ammonia but none of the isolates hydrolyzed chitin. Siderophore production and antifungal activity of these isolates except Mesorhizobium were exhibited by 10-12.77% isolates. HCN production was more common trait of Pseudomonas (88.89%) and Bacillus (50%). On the basis of multiple plant growth promoting activities, eleven bacterial isolates (seven Azotobacter, three Pseudomonas and one Bacillus) were evaluated for their quantitative IAA production, and broad-spectrum (active against three test fungi) antifungal activity. Almost at all concentration of tryptophan (50-500 microg/ml), IAA production was highest in the Pseudomonas followed by Azotobacter and Bacillus isolates. Azotobacter isolates (AZT(3), AZT(13), AZT(23)), Pseudomonas (Ps(5)) and Bacillus (B(1)) showed broad-spectrum antifungal activity on Muller-Hinton medium against Aspergillus, one or more species of Fusarium and Rhizoctonia bataticola. Further evaluation of the isolates exhibiting multiple plant growth promoting (PGP) traits on soil-plant system is needed to uncover their efficacy as effective PGPR.     

Investigation of biological activities of various 1,2,3-triazole compounds: Their effects on cholinesterase enzymes,determination of antioxidant capacity and antimicrobial activity

1,2,3-triazoles are pharmaceutically significant compounds that have attracted recent interest from medicinal chemists because of their important biological activities. Addressed herein, some 1,2,3-triazoles were synthesized to investigate the inhibitory activities against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes, antioxidant capacity, and antimicrobial effect. The antioxidant profile of 1,2,3-triazoles determined by varied bioanalytical antioxidant methods, including 2,2′-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS^.+), 1,1-diphenyl-2-picrylhydrazil (DPPH·), cupric ion (Cu²⁺) and ferric ion (Fe³⁺) ascorbic acid, butylated hydroxyanisole (BHA), and butylated hydroxytoluene (BHT) were used as the standard compounds. In addition, the antibacterial and antifungal activities of these compounds were investigated against seven bacteria and three fungal species using the hollow agar method. As a result of these studies, it was determined that compound 4 showed the best antimicrobial activity and antioxidant activity close to the standards. Inhibitory effects and kinetic studies of these molecules on cholinesterase enzymes were performed. According to the results obtained, compound 4 showed stronger AChE inhibition and compound 3 stronger BChE inhibition compared to other compounds. In kinetic studies, it was found that AChE showed noncompetitive inhibition by compound 4, and BChE showed competitive inhibition by compound 3.     

耳状网褶菌的化学成分

从野生真菌耳状网褶菌（Paxillus pamuoides Fr.)子实体中分得4个化合物,经光谱和化学方法分别鉴定为（2S,3S,4R,2′R）-2－（2′－羟基二十四碳酰氨基）十八碳－1,3,4－三醇（1）、5α,8α－表二氧－（22E,24R）－麦角甾－6,22－二烯－3β-醇[5α,8α-epidioxy-(22E,24R)-ergosta-6,22-dien-3β－o1,2]、（22E,24R）－麦角甾－4,6,8（14）,22－四烯－3－酮[(22E,24R)-ergosta-4,6,8(14),22-tetraen-3-one,3]和对羟基苯甲酸乙酯（ethyl 4-hydroxybenzoate,4)。其中化合物4作为天然产物属首次报道。化合物1－4为本科真菌中首次分得。     

Antibacterial and antifungal activities of andrachne cordifolia muell

The crude methanolic extract of Andrachne cordifolia Muell. (Euphorbiaceae) and its various fractions in different solvent systems (chloroform, ethyl acetate and n- butanol) were screened for antibacterial and antifungal activities. Crude extract and subsequent fractions demonstrated moderate to excellent antibacterial activities against the tested pathogens. Highest antibacterial activity was displayed by both chloroform and ethyl acetate fractions (100%) followed by the crude extract (68%) against Salmonella typhi. Similarly, crude extract and its subsequent fractions showed mild to excellent activities in antifungal bioassay with maximum (76%) antifungal activity against Microsporum canis by the chloroform fraction followed by the crude extract (65%).     

Antifungal and antibacterial activities of Taxus wallichiana Zucc

Current study was undertaken to evaluate the in vitro antifungal and antibacterial potential of methanol extract and subsequent fractions obtained after partitioning in organic solvents with variable polarity of the aerial parts of the tree Taxus wallichiana Zucc. Traditionally, this plant is often used in folk medicines in Pakistan for treating microbial infections. In order to rationalize the traditional use, methanol extracts of leaf, bark, and heartwood of Taxus wallichiana Zucc. were tested against six bacteria and six fungal strains using the Hole diffusion and macro-dilution methods. All extracts and fractions displayed significant antimicrobial effect. Only three fungal strains, Trichophyton longifusus, Microspoum canis, and Fusarium solani were susceptible to the extracts and fractions with MICs ranging from 0.08 to 200 mg/mL. In case of bacterial strains, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhi were susceptible to the extracts and fractions with MICs ranging from 0.08 to 200 mg/mL. Comparison results were carried out using imipinem, miconazole and amphotericin B as standard antibiotics.     

Estimation of mycelial growth of basidiomycetes by means of chitin determination

After hydrolysis of chitin in 6 M HCl, the glucosamine produced was assayed colorimetrically. The pH of the hydrolysate was adjusted to a value close to three by addition of Na acetate; this procedure avoids the elimination of excess acid by evaporation under reduced pressure or freeze-drying. Under these conditions, the amount of glucosamine determined by the assay represented an average of 90% of the amount which would result from a total hydrolysis of the chitin. The method was used to assay the chitin in the mycelia of basidomycetes obtained in vitro. The measured amount of glucosamine was proportional to the mycelial biomass and allowed the estimation of fungal growth.     

Synthesis and characterization of some hydroxypyridone derivatives and their evaluation as antimicrobial agents

The synthesis, in vitro antimicrobial activities of some novel hydroxy pyridines supported with various pharmacophores is described. Twenty-six out of the tested 58 compounds exhibited variable inhibitory effects on the growth of the tested Gram positive and Gram negative bacteria. The tested compounds revealed better activity against the Gram positive rather than the Gram negative strains. The synthesized hydroxypyridones have shown very significant inhibitory effect against Staphylococcus aureus and Bacillus subtilis. Twelve compounds namely; 5d, 5f, 6a, 6b, 8b, 18b, 18c, 19c, 21d, 22b, 22d and 23d were able to produce appreciable growth inhibitory activity against Candida albicans when compared to Clotrimazole. Among these, 22d proved to be the most potent antifungal agent.     

Fungal proteolytic enzymes: Features of the extracellular proteases of xylotrophic basidiomycetes

Fungal proteolytic enzymes attract the attention of researches due to such features as high diversity, broad substrate specificity, and stability under extreme conditions. Their functional role is also interesting; it includes a number of processes from the hydrolysis of macromolecular substrates under extremely low nitrogen content to initiation and maintenance of pathogenesis. In the present review, the features of the extracellular proteases of xylotrophic basidiomycetes are discussed. This group is important for the functioning of biological communities and participates in the biological destruction of plant debris; moreover, they are widely used as a source of nutrients and medicines. The review stresses the issues of classification of fungal proteases, their biochemical characteristics and physiological role, as well as the regulation of their activity in the course of fungal growth.     

Design,synthesis and evaluation of some 1,3,5-triazinyl urea and thiourea derivatives as antimicrobial agents

In an effort to establish new candidates with improved antimicrobial activities we report here the synthesis and in vitro biological evaluation of various series of compounds (5a-j) and (7a-j) which were evaluated against two Gram positive (S. aureus, B. subtilis), two Gram negative (S. typhosa, E. coli) strains and a yeast-like fungi (C. albicans) using the micro-dilution procedure. Among the synthesized compounds 2-(cyclohexyl amino)-4-(3,4-dimethoxy phenyl ethyl thioureido)-6-(2-chloro phenyl ureido) s-triazine (7e) and 2-(cyclohexyl amino)-4-(3,4-dimethoxy phenyl ethyl thioureido)-6-(4-chloro phenyl ureido) s-triazine (7g) proved to be effective with MIC (0.019 mg ML^?1) against S. typhosa & E. coli respectively.     

新疆具抗菌活性的植物资源

对分属于新疆41科88种高等植物的抗菌活性进行了归纳。这些抗菌植物主要分布在菊科、唇形科、豆科、百合科、蓼科和伞形科。对人体和植物病原菌抗性较强的有土木香(Inula helenium)、苍耳(Xanthium sibiricum)、蓖麻(Ricinus communis)、荆芥(Schizonepeta tenuifolia)、石榴(Punica granatum)、孜然芹(Cuminum cyminum),以及蒿属(Artemisia spp．)、槐属(Sophora spp．)和酸模属(Rumex spp．)植物。新疆植物的抗菌活性成分和结构阐明还需要进行深入的研究。