Discovery of dual PKS involved in sclerotiorin biosynthesis in Penicillium meliponae using genome mining and gene knockout.

Fungi of the genus Penicillium section Sclerotiora have as their main characteristic the presence of orange-pigmented mycelium, which is associated with sclerotiorin, a chlorinated secondary metabolite of the azaphilone subclass of polyketides. Sclerotiorin presents anti-diabetes, antioxidant, anti-inflammatory, anti-Alzheimer, antiviral, and antimicrobial activities, which has always attracted the attention of researchers worldwide. During our ongoing search for azaphilone-producing Amazonian fungi, the strain of Penicillium MMSRG-058 was isolated as an endophyte from the roots of Duguetia stelechantha and showed great capacity for producing sclerotiorin-like metabolites. Using multilocus phylogeny, this strain was identified as Penicillium meliponae. Moreover, based on the genome mining of this strain through the reverse approach, a cluster of putative biosynthetic genes (BGC) responsible for the biosynthesis of sclerotiorin-like metabolites (scl cluster) was identified. The knockout of the sclA (highly reducing PKS) and sclI (non-reducing PKS) genes resulted in mutants with loss of mycelial pigmentation and terminated the biosynthesis of sclerotiorin-like metabolites: geumsanol B, chlorogeumsanol B, 7-deacetylisochromophilone VI, isochromophilone VI, ochrephilone, isorotiorin, and sclerotiorin. Based on these results, a biosynthetic pathway was proposed considering the homology of BGC scl genes with the azaphilone BGCs that have already been functionally characterized.

Larvicidal Activities against Aedes aegypti of Supernatant and Pellet Fractions from Cultured Bacillus spp. Isolated from Amazonian Microenvironments.

The Aedes aegypti mosquito is the primary vector of Dengue, Chikungunya and Zika causing major problems for public health, which requires new strategies for its control, like the use of entomopathogenic microorganisms. In this study, bacteria from various Amazonian environments were isolated and tested for their pathogenicity to A. aegypti larvae. Following thermal shock to select sporulated Bacillus spp., 77 bacterial strains were isolated. Molecular identification per 16S RNA sequences revealed that the assembled strains contained several species of the genus Bacillus and one species each of Brevibacillus, Klebsiella, Serratia, Achromobacter and Brevundimonas. Among the isolated Bacillus sp. strains, 19 showed larvicidal activity against A. aegypti. Two strains of Brevibacillus halotolerans also displayed larvicidal activity. For the first time, larvicidal activity against A. aegypti was identified for a strain of Brevibacillus halotolerans. Supernatant and pellet fractions of bacterial cultures were tested separately for larvicidal activities. Eight strains contained isolated fractions resulting in at least 50% mortality when tested at a concentration of 5 mg/mL. Further studies are needed to characterize the active larvicidal metabolites produced by these microorganisms and define their mechanisms of action.

Polycarpol in Unonopsis, Bocageopsis and Onychopetalum Amazonian species: chemosystematical implications and antimicrobial evaluation

Polycarpol, a recurrent lanostane-type triterpene in Annonaceae family, was confirmed by thin layer chromatography and mass spectrometry analysis in the aerial parts (twigs and trunk barks) of Unonopsis duckei R.E. Fr., U. floribunda Diels, U. rufescens (Baill.) R.E. Fr., U. stipitata Diels, Onychopetalum amazonicum R.E. Fr. and Bocageopsis pleiosperma Maas. Its chemotaxonomic significance was discussed for these three genera, as well for the Annonaceae family. In addition, the antimicrobial activity against several strains of microorganisms was evaluated for the first time for this compound, being observed significant antibacterial activity against Staphylococcus aureus (ATCC 6538), Staphylococcus epidermidis (ATCC 1228) and Escherichia coli (ATCC 10538 and ATCC 10799) with minimal inhibitory concentration values between 25 and 50 μg ml−1.

Chemical composition and antimicrobial evaluation of the essential oils of Bocageopsis pleiosperma Maas.

Essential oils from the leaves, twigs and barks of Bocageopsis pleiosperma Maas were obtained by using hydrodistillation and analysed by using gas chromatography coupled to mass spectrometry. Several compounds (51) were detected and identified, being ß-bisabolene the main component in all aerial parts of the plant, with higher concentration in the leaves (55.77%), followed by barks (38.53%) and twigs (34.37%). In order to increase the biological knowledge about the essential oil of Bocageopsis species, antimicrobial activities were evaluated against the microorganisms Escherichia coli, Staphylococcus epidermidis, Enterobacter aerogenes, Candida tropicalis, Candida dubliniensis, Candida glabrata and Candida albicans. The essential oil obtained from the barks exhibited a moderate effect against S. epidermidis ATCC 1228 (MIC = 250 µg/mL), while the other oils did not exhibit antimicrobial activity. These results represent the first report about the chemical composition of B. pleiosperma and the first antimicrobial evaluation with a Bocageopsis species.

Production of 5-hydroxy-7-methoxy-4-methylphthalide in a culture of Penicillium crustosum.

The chemical reactions carried out by microorganisms have been used as a tool in modern chemistry. This paper reports the production of mycophenolic acid and a new phthalide by the endophytic fungus Penicillium crustosum obtained from coffee seeds. The fungus was cultivated in a liquid medium for a period of seven days and after that the culture medium was divided into four treatments: A, B, C and D, to which different organic substances were added. Treatment A was maintained as the control to evaluate the occurrence of biotransformation. Organic acids were added to the culture media of treatments B (ferulic and quinic acids) and C [cinnamic and 3,4-(methylenedioxy) cinnamic acids], and caffeine was added in the treatment D. All these organic compounds were dissolved in DMSO, and the fermentation was maintained for more 13 days, totalizing 20 days. Mycophenolic acid was isolated from the culture with no added acids (treatment A). Mycophenolic acid and a new phthalide, 5-hydroxy-7-methoxy-4-methylphthalide were isolated from treatments B and C, and mycophenolic acid and caffeine (added to the culture medium) were isolated from treatment D. The structures were determined by NMR techniques and confirmed by MS and MS/MS techniques.

Mauritic acid: a new dammarane triterpene from the roots of Mauritia flexuosa L.f. (Arecaceae).

A new dammarane triterpene named mauritic acid (1) was isolated from the roots of Mauritia flexuosa L.f. The complete structural assignment of this new compound was elucidated from spectroscopic methods. Moreover, this compound was evaluated for its cytotoxicity against human cancer cell lines (OVCAR-8, PCM3, NCIH358M and different leukaemia cell strains). The mauritic acid presented significant cytotoxicity against OVCAR-8, PCM3 and NCIH358M cell lines with IC50 3.02, 2.39 and 6.19 µM, respectively. The triterpenes 1 and 2 were also tested for their antimicrobial activity against 15 strains of microorganisms, including fungi and bacteria, with the best minimal inhibitory concentration values ranging from 50.8 to 203.5 µM.

Triterpenes and flavonoids from the roots of Mauritia flexuosa

Mauritia flexuosa L. f., Arecaceae, is an endemic species of South America. This species was studied with the intent to isolate the constituents of its roots. After the fractionation of the n-hexane and methanolic extracts from the roots of M. flexuosa, six triterpenes were obtained: friedelin, taraxerone, lupenyl acetate, lupenone, betulin and betulinic acid, along with three flavonoids: rutin, quercitrin and quercetin. All the compounds were identified by analysis of NMR and MS data and comparison with the literature. All those compounds are been reported for the first time in Mauritia, and the chemosystematic significance of the flavonoids isolated in this genus is discussed.

Co-production of bisphenylpropanoid amides and meroterpenes by an endophytic Penicillium brasilianum found in the root bark of Melia azedarach.

A fungus, isolated from the root bark of Melia azedarach (Meliaceae), from which a series of meroterpenes have been reported, was identified as Penicillium brasilianum based on analysis of the ITS region of ribosomal DNA. From a rice culture of this fungus, the known phenylpropanoid amides brasiliamide A and B were obtained together with and a new, slightly modified congener, along with the meroterpenoids preaustinoid A1, preaustinoid B2 and austinolide. The compounds were isolated by the use of combined chromatographic procedures and identified by physical methods, mainly 1D and 2D NMR experiments, with distinction for 1H{15N} HMBC applied to brasiliamide A. The amides were tested for their antimicrobial activity and showed only weak inhibitory effects, against a set of pathogenic bacteria.

Koninginins, phospholipase A2 inhibitors from endophytic fungus Trichoderma koningii.

Many isolated compounds from endophytic fungus have been useful to human beings, mainly those with medicinal applications and particularly those that can be used in inflammatory processes. Trichoderma fungi produce substances known as koninginins that have great structural similarity to compounds like flavonoids and vitamin E, which are able to inhibit the phospholipase A(2) (PLA(2)). In this work, koninginins A, E and F (KonA, KonE and KonF, respectivamente) isolated from Trichoderma koningii had their capabilities of inhibiting edema-inducing, myotoxic and enzymatic activities of the total venom of Bothrops jararacussu (jararacuçu) snake analyzed, as well as one of its homolog forms of phospholipases A(2) (bjPLA(2)-group IIB) and human secreted PLA(2) protein fusion (hsPLA(2)-group IIA). KonA was not efficient in inhibiting the three activities analyzed in all the tests performed. Nevertheless, KonE and KonF present great capability in inhibiting the effects provoked not only by the venom but also by both PLA(2). The activities inhibition shown by KonE and KonF over the enzymes is significantly higher than those obtained over the total venom. KonE and KonF were slightly more efficient in the inhibition of the group IIB (bjPLA(2)) PLA(2) effects than in the inhibition of the group IIA (hsPLA(2)) PLA(2) effects. KonE and KonF structures are similar to vitamin E and, possibly, the action mode of these molecules is similar to the one produced by the vitamin. These results, apparently, indicate that koninginins E and F, as well as vitamin E, present structural regions that might be used as start points in seeking for new and specific anti-inflammatory drugs against such enzymes.

Bioprospecting highly diverse endophytic Pestalotiopsis spp. with antibacterial properties from Maytenus ilicifolia, a medicinal plant from Brazil.

Thirteen endophytic fungal strains of the genus Pestalotiopsis were isolated from the medicinal plant Maytenus ilicifolia Mart. ex. Reiss (commonly known as "espinheira santa") and their antimicrobial properties were investigated. Two isolates were successful in inhibiting the growth of the tested microorganisms (Escherichia coli, Klebsiella pneumoniae, Micrococcus luteus, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus (MRSA)) using the technique of bioautographic thin-layer chromatography (TLC) agar overlay assay. An analysis based on a polyphasic approach integrating taxonomic information, morphological traits, RAPD markers, and the sequencing of the ITS1-5.8S-ITS2 of the rDNA led to the assignment of the isolates as belonging to the species Pestalotiopsis microspora, Pestalotiopsis vismiae, and Pestalotiopsis leucothoes. Therefore, the present study presents a new approach to the study of endophytic fungi of the genus Pestalotiopsis.

A complete approach for recombinant protein expression training: From gene cloning to assessment of protein functionality*.

A practical course was given to undergraduate biology students enrolled in the elective course "Introduction to Genetic Engineering" at the Federal University of São Carlos (UFSCar), São Paulo, Brazil. The goal of the course was to teach current molecular biology tools applied to a real research situation that could be reported by the students themselves. The purpose was to produce a plant recombinant protein and demonstrate a heretofore unreported biological activity. Cystatins, natural inhibitors of cysteine proteases, were proposed for these studies. Initially, the students searched for plant cystatin cDNA sequences in the NCBI databases and selected the Oryzacystatin I gene (ocI) from rice, Oriza sativa, as the target gene for this study. Total RNA was extracted from rice-germinating seeds and primers containing restriction sites for NdeI and EcoRI were designed based on the ocI cDNA sequence and then used to amplify the open reading frame (ORF). RT-PCR amplification provided a band of the expected size for ocI ORF (309 bp). The PCR product was cut with NdeI and EcoRI restriction enzymes and cloned directly in the pET28a expression vector digested with the same enzymes. A pET28-ocI recombinant clone was selected, checked by sequencing, and used to transform Escherichia coli BL21 (DE3) expression strain. After induction of the bacteria with isopropylthiogalactoside and cellular disruption, the His-tagged OCI protein, present mainly in the soluble fraction, was purified by affinity chromatography in a nickel column. The purified protein was successfully used to inhibit fungal growth (Trichoderma reesei). The results were discussed extensively and the students contributed to the writing of this article, of which they are co-authors.

Three highly oxygenated caryophyllene sesquiterpenes from Pestalotiopsis sp., a fungus isolated from bark of Pinus taeda.

A Pestalotiopis sp. was isolated from the trunk bark of Pinus taeda. The fungus was cultivated in liquid medium and produced three highly oxygenated caryophyllene sequiterpene derivatives, named pestalotiopsolide A, taedolidol and 6-epitaedolidol, respectively. The sesquiterpenes were isolated by silica gel based chromatographic procedures and their structures were elucidated by NMR spectroscopic data.