Aspergillus sp. A31 and Curvularia geniculata P1 mitigate mercury toxicity to Oryza sativa L.

Aspergillus sp. A31 and Curvularia geniculata P1 are endophytes that colonize the roots of Aeschynomene fluminensis Vell. and Polygonum acuminatum Kunth. in humid environments contaminated with mercury. The two strains mitigated mercury toxicity and promoted Oryza sativa L growth. C. geniculata P1 stood out for increasing the host biomass by fourfold and reducing the negative effects of the metal on photosynthesis. Assembling and annotation of Aspergillus sp. A31 and C. geniculata P1 genomes resulted in 28.60 Mb (CG% 53.1; 10,312 coding DNA sequences) and 32.92 Mb (CG% 50.72; 8,692 coding DNA sequences), respectively. Twelve and 27 genomes of Curvularia/Bipolaris and Aspergillus were selected for phylogenomic analyzes, respectively. Phylogenetic analysis inferred the separation of species from the genus Curvularia and Bipolaris into different clades, and the separation of species from the genus Aspergillus into three clades; the species were distinguished by occupied niche. The genomes had essential gene clusters for the adaptation of microorganisms to high metal concentrations, such as proteins of the phytoquelatin-metal complex (GO: 0090423), metal ion binders (GO: 0046872), ABC transporters (GO: 0042626), ATPase transporters (GO: 0016887), and genes related to response to reactive oxygen species (GO: 0000302) and oxidative stress (GO: 0006979). The results reported here help to understand the unique regulatory mechanisms of mercury tolerance and plant development.

Streptomyces griseocarneus R132 expresses antimicrobial genes and produces metabolites that modulate Galleria mellonella immune system.

Actinobacteria is a phylum composed of aerobic, Gram-positive, and filamentous bacteria with a broad spectrum of biological activity, including antioxidant, antitumor, and antibiotic. The crude extract of Streptomyces griseocarneus R132 was fractionated on a C18 silica column and the isolated compound was identified by 1H and 13C nuclear magnetic resonance as 3-(phenylprop-2-enoic acid), also known as trans-cinnamic acid. Antimicrobial activity against human pathogens was assayed in vitro (disk-diffusion qualitative test) and in vivo using Galleria mellonella larvae (RT-qPCR). The methanol fractions 132-F30%, 132-F50%, 132-F70%, and 132-F100% inhibited the Escherichia coli (ATCC 25922) and Staphylococcus aureus (MRSA) growth in vitro the most effectively. Compared with the untreated control (60-80% of larvae death), the fractions and isolated trans-cinnamic acid increased the survival rate and modulated the immune system of G. mellonella larvae infected with pathogenic microorganisms. The anti-infection effect of the S. griseocarneus R132 fermentation product led us to sequence its genome, which was assembled and annotated using the Rast and antiSMASH platforms. The assembled genome consisted of 227 scaffolds represented on a linear chromosome of 8.85 Mb and 71.3% of GC. We detected conserved domains typical of enzymes that produce molecules with biological activity, such as polyketides and non-ribosomal and ribosomal peptides, indicating a great potential for obtaining new antibiotics and molecules with biotechnological application. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-021-02942-1.

Dark septate endophytic fungi mitigate the effects of salt stress on cowpea plants.

The association of plant with microorganisms, such as dark septate endophytic fungi, has mitigated the harmful effects of chemical, physical, and biological agents on the host. The objective of this work was to evaluate the interaction of the dark septate endophytic fungi with cowpea plants under salt stress. Endophytic fungi were isolated from Vochysia divergens root system, and molecular identification of fungi was performed by sequencing the ITS region. We selected and identified Sordariomycetes sp1-B'2 and Melanconiella elegans-21W2 for their ability to infect V. divergens root in vitro with development of typical dark septate fungi structures. Cowpea plants-inoculated or not inoculated with Sordariomycetes sp1-B'2 and M. elegans 21W2-were cultivated in 5-L pots under greenhouse conditions and submitted to four different electrical conductivities of irrigation water (1.2, 2.2, 3.6, and 5.0 dS m-1). The salinity caused decrease in leaf concentration of K and increased leaf concentration of calcium, sodium, and chlorine; and no influence of dark septate endophytic fungi was observed in these responses. On the other hand, root colonization with Sordariomycetes sp1-B'2 and M. elegans 21W2 resulted in improved nutrition with N and P in cowpea under salt stress, favoring the growth and rate of liquid photosynthesis. However, such positive responses were evident only at moderate levels of salinity.

Draft Genome Sequences of Pseudomonas sp. Strain 382 and Pantoea coffeiphila 342, Endophytic Bacteria Isolated from Brazilian Guarana [Paullinia cupana (Mart.) Ducke].

Pseudomonas sp. strain 382 and Pantoea coffeiphila 342 are two endophytic bacterial strains isolated from Paullinia cupana (guarana) seeds. Their draft genome sizes were 5.96 and 6.38 Mbp, with 315 and 266 scaffolds and 52% and 62% GC content, respectively.

Draft Genome Sequence of the Mercury-Resistant Strain Acinetobacter baumannii I43.

Here, we report the draft genome sequence of the Acinetobacter baumannii strain I43, which is highly resistant to mercury. The Illumina-based sequence analysis revealed a genome of approximately 4,520,353 bp composed of 4,091 coding sequences.

18-Des-hydroxy Cytochalasin: an antiparasitic compound of Diaporthe phaseolorum-92C, an endophytic fungus isolated from Combretum lanceolatum Pohl ex Eichler.

Chemical investigation of the ethyl acetate extract from the endophytic fungus Diaporthe phaseolorum-92C (92C) isolated from the roots of Combretum lanceolatum led to the isolation of 18-des-hydroxy Cytochalasin H (compound 1). The trypanocidal and schistosomicidal activity and cytotoxicity of the extract from 92C were evaluated. The schistosomicidal, leishmanicidal, antimicrobial, and antioxidant actions, as well as the antitumor activity against the breast cancer cells MDA-MB-231 and MCF-7, and the cytotoxicity towards normal human lung fibroblasts GM07492A of compound 1 was tested. The extract from 92C (20 µg/mL) exerted potent trypanocidal activity, reducing 82% of the number of amastigotes and trypomastigotes of Trypanosoma cruzi. Compound 1 at 50 µg/mL killed 50% of Schistosoma mansoni adult worms. Compound 1 reduced the viability of Leishmania amazonenses promastigotes (IC50 = 9.2 µg/mL) and of the cancer cells MDA-MB-231 and MCF-7 (IC50 = 17.5 and 8.88 µg/mL, respectively), presented moderate antioxidant activity, and gave IC50 of 2049.7 ± 39.9 µg/mL for the cytotoxicity towards normal cells GM07492A. This knowledge is highly relevant to the search for new promising compounds for therapeutic purposes.

Bioactive compounds of Aspergillus terreus-F7, an endophytic fungus from Hyptis suaveolens (L.) Poit.

The compounds terrein (1), butyrolactone I (2), and butyrolactone V (3) were isolated from the ethyl acetate extract (EtOAc) of the endophytic fungus Aspergillus terreus-F7 obtained from Hyptis suaveolens (L.) Poit. The extract and the compounds presented schistosomicidal activity against Schistosoma mansoni; at 100 µg/mL for EtOAc extract, 1297.3 µM for compound 1, 235.6 µM for compound 2, and 454.1 µM for compound 3, they killed 100% of the parasites after 72 h of treatment. Compounds 1, 2, and 3 exerted moderate leishmanicidal activity against Leishmania amazonensis (IC50 ranged from 23.7 to 78.6 µM). At 235.6 and 227.0 µM, compounds 2 and 3, respectively, scavenged 95.92 and 95.12% of the DPPH radical (2,2-diphenyl-1-picryl-hydrazyl), respectively. Regarding the cytotoxicity against the breast tumor cell lines MDA-MB-231 and MCF-7, compound 2 gave IC50 of 34.4 and 17.4 µM, respectively, while compound 3 afforded IC50 of 22.2 and 31.9 µM, respectively. At 117.6 µM, compound 2 inhibited the growth of and killed the pathogen Escherichia coli (ATCC 25922). Compounds 1, 2, and 3 displayed low toxicity against the normal line of human lung fibroblasts (GM07492A cells), with IC50 of 15.3 × 103, 3.4 × 103, and 5.8 × 103 µM, respectively. This is the first report on (i) the in vitro schistosomicidal and leishmanicidal activities of the EtOAc extract of A. terreus-F7 and compounds 1, 2, and 3; and (ii) the antitumor activity of compounds 2 and 3 against MDA-MB-231 and MCF-7 cells.