The Diversity,Metabolomics Profiling,and the Pharmacological Potential of Actinomycetes Isolated from the Estremadura Spur Pockmarks (Portugal)

The Estremadura Spur pockmarks are a unique and unexplored ecosystem located in the North Atlantic, off the coast of Portugal. A total of 85 marine-derived actinomycetes were isolated and cultured from sediments collected from this ecosystem at a depth of 200 to 350 m. Nine genera, Streptomyces, Micromonospora, Saccharopolyspora, Actinomadura, Actinopolymorpha, Nocardiopsis, Saccharomonospora, Stackebrandtia, and Verrucosispora were identified by 16S rRNA gene sequencing analyses, from which the first two were the most predominant. Non-targeted LC-MS/MS, in combination with molecular networking, revealed high metabolite diversity, including several known metabolites, such as surugamide, antimycin, etamycin, physostigmine, desferrioxamine, ikarugamycin, piericidine, and rakicidin derivatives, as well as numerous unidentified metabolites. Taxonomy was the strongest parameter influencing the metabolite production, highlighting the different biosynthetic potentials of phylogenetically related actinomycetes; the majority of the chemical classes can be used as chemotaxonomic markers, as the metabolite distribution was mostly genera-specific. The EtOAc extracts of the actinomycete isolates demonstrated antimicrobial and antioxidant activity. Altogether, this study demonstrates that the Estremadura Spur is a source of actinomycetes with potential applications for biotechnology. It highlights the importance of investigating actinomycetes from unique ecosystems, such as pockmarks, as the metabolite production reflects their adaptation to this habitat.     

Survival of Curtobacterium flaccumfaciens pv. flaccumfaciens in weeds

Weeds are important alternative hosts of pathogens, responsible for the survival and spread of phytopathogenic bacteria. Our study evaluated the potential of weeds as hosts of Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff), causal agent of bacterial wilt, one of the main diseases of common beans. Cff survival was evaluated in the phyllosphere and in the rhizosphere of 21 weeds, in four experiments under field conditions, during the years 2018 and 2019. The aerial part of the plant was inoculated by spraying bacterial suspension (10⁷ cfu/ml) of Cff, while the soil of the growing pots was infested with the same suspension. Cff survival was evaluated every 7 days, for 70 days. The identity of the bacterium was confirmed by PCR with the specific primers CffFOR2 and CffREV4, from strains recovered from all samples. Principal component analysis (PCA) showed that high temperatures and rainfall reduced Cff survival in the phyllosphere, while high temperatures reduced the survival of the bacterium in the rhizosphere. Our results demonstrated that Amaranthus viridis (family Amaranthaceae), Conyza bonariensis, Emilia fosbergii, Galinsoga parviflora, Gnaphalium purpureum (Asteraceae), Raphanus sativus, Lepidium virginicum (Brassicaceae), Commelina benghalensis (Commelinaceae), Ipomoea triloba (Convolvulaceae), Cyperus rotundus (Cyperaceae), Senna obtusifolia (Fabaceae), Digitaria insularis (Poaceae), Nicandra physalodes, and Solanum americanum (Solanaceae) are potential hosts for Cff. Their eradication in common bean fields is recommended, especially in fields with a history of bacterial wilt occurrence.     

Environmental Degradation at a Public Park in Southern Brazil as Revealed Through a Genotoxicity Test (MN) on Peripheral Blood Cells from Poecilia vivipara (Teleostei)

The effects of anthropogenic activities on water, environment, and consequently quality of life can be evaluated using genetic, biochemical, and microbiological parameters. Regarding genetic parameters, the micronucleus test is a fast, efficient, inexpensive method for detecting alterations in genetic material induced by a variety of genotoxic agents. In the present study, blood cells from Poecilia vivipara from the Belém River in the city of Curitiba, Paraná, Brazil were evaluated for genotoxic effects stemming from human-produced pollution, as expressed by the micronucleus. The water in the river was evaluated with regard to physiochemical and microbiological parameters as well as for heavy metals. The analysis revealed the presence of copper, zinc, and nickel, with high concentrations of copper. The micronucleus analysis revealed significant differences in relation to the groups (study and control), suggesting a positive relation between the water quality of the Belém River and micronucleus expression as a result of the pollution to which this river is subjected.     

Adsorption of chromium(VI) ions on Brazilian smectite: Effect of contact time,pH, concentration,and calorimetric investigation

The original smectite clay mineral has been collected from Amazon region, Brazil. The compound 2-aminomethylpyridine (AMP) was anchored onto Amazon smectite surface by heterogeneous route. The natural (SMC) and modified (SMC_AMP) smectite samples were characterized by elemental analysis, scanning electron microscopy, N₂ adsorption, X-ray diffraction, and silicon-29 and carbon-13 nuclear magnetic resonance. Due to the increment of basic centers attached to the pendant chains, the metal adsorption capability of the final chelating material, was found to be higher than the precursor. The ability of these materials to remove Cr(VI) from aqueous solution was followed by a series of adsorption isotherms at room temperature and pH 4.0. The maximum number of moles adsorbed was determined to be 1.16 and 1.87 mmol g^− 1 for SMC and SMC_AMP, respectively. In order to evaluate the clay samples as adsorbents in dynamic system, a glass column was fulfilled with clay samples (1.0 g) and it was fed with 2.0 × 10^− 4 mol dm^− 3 Cr(VI) at pH 4.0. The energetic effects caused by metal cation adsorption were determined through calorimetric titrations. Thermodynamics indicated the existence of favorable conditions for such Cr(VI)–nitrogen interactions.     

Effects of fish heme protein structure and lipid substrate composition on hemoglobin-mediated lipid oxidation

Hemoglobin (Hb) promoted lipid oxidation more effectively in washed tilapia as compared to washed cod in spite of a 2.8-fold higher polyenoic index in the washed cod. This suggested that increasing the fatty acid unsaturation of the substrate did not accelerate the onset of lipid oxidation. Substantial phospholipid hydrolysis in the washed cod was observed, which has the potential to inhibit lipid oxidation. MetHb formation and lipid oxidation occurred more rapidly at pH 6.3 as compared to pH 7.4. Trout Hb autoxidized faster and was a better promoter of lipid oxidation as compared to tilapia Hb. The greater ability of trout Hb to promote lipid oxidation was attributed in part to its lower conformational and structural stability based on secondary and tertiary structure, acid-induced unfolding, and thermal aggregation measurements. It is suggested that the structural instability and lipid oxidation capacity of trout Hb were at least partly due to low hemin affinity. Trout and tilapia Hb were equivalent in their ability to cause lipid oxidation in washed cod muscle heated to 80 degrees C. Apparently, these high temperatures denature both trout and tilapia Hb to such an extent that any differences in conformational stability observed at lower temperatures were negated.     

Phenolic profile of Cydonia oblonga Miller leaves

Cydonia oblonga Miller leaves phenolic compounds were analyzed by reversed-phase HPLC/DAD and HPLC/UV. Qualitative and quantitative analysis of phenolics were carried out in a total of 36 samples of quince leaves from three different geographical origins of Northern (Bragan?a and Carrazeda de Ansi?es) and Central Portugal (Covilh?) and three collection months (June, August, and October of 2006). These leaves presented a common phenolic profile composed by nine compounds: 3- O-, 4- O- and 5- O-caffeoylquinic acids, 3,5- O-dicaffeoylquinic acid, quercetin-3- O-galactoside, quercetin-3- O-rutinoside, kaempferol-3- O-glycoside, kaempferol-3- O-glucoside, and kaempferol-3- O-rutinoside. 5- O-caffeoylquinic acid was the major phenolic compound (36.2%), followed by quercetin 3- O-rutinoside (21.1%). Quince leaves are characterized by higher relative contents of kaempferol derivatives than fruits (pulps, peels, and seeds), especially in what concerns kaempferol-3- O-rutinoside (12.5%). C. oblonga leaves total phenolic content was very high, varying from 4.9 to 16.5 g/kg dry matter (mean value of 10.3 g/kg dry matter), indicating that these leaves can be used as a good and cheap source of bioactive constituents. Significantly differences were observed in 3- O-caffeoylquinic and 3,5- O-dicaffeoylquinic acids contents, according to geographical provenance and harvesting month, suggesting a possible use of these compounds as geographical origin and/or maturity markers.     

Biologic and genetic characteristics of Toxoplasma gondii isolates in free-range chickens from Costa Rica, Central America

The prevalence of Toxoplasma gondii in free-ranging chickens is a good indicator of the prevalence of T. gondii oocysts in the soil because chickens feed from the ground. The prevalence of T. gondii in 144 free-range chickens (Gallus domesticus) from Costa Rica was determined. Antibodies to T. gondii were assayed by the modified agglutination test (MAT), and found in 60 (40.1%) of 144 chickens with titers of 1:5 in 16, 1:10 in 5, 1:20 in 2, 1:40 in 3, 1:80 in 5, and 1:160 or higher in 29. Tissues of all chickens were bioassayed for T. gondii in mice or cats. Hearts and brains of 52 chickens with titers of 1:5 or higher and 16 chickens with doubtful titers were pooled and bioassayed in mice. Tissues from 76 chickens with MAT titers of 1:10 or less were pooled and fed to three T. gondii-free cats. Fecal floats of cats were bioassayed orally in mice but were negative for T. gondii oocysts. T. gondii was isolated by bioassay in mice from 32 chickens with MAT titers of 1:10 or higher. All infected mice from 4 of the 32 isolates died of toxoplasmosis. Genotyping of these 32 isolates using polymorphisms at the loci SAG1, SAG2, SAG3, BTUB and GRA6 revealed five genotypes. Five isolates had type I alleles and one isolate had type III alleles at all loci. The rest 26 isolates contained the combination of type I and II or I and III alleles and were divided into three genotypes. None was found to have genotype II alleles at all five loci. This is the first report of genetic characterization of T. gondii isolates from Costa Rica, Central America.     

An improved protocol for electrotransformation of Corynebacterium pseudotuberculosis

We developed an improved protocol for the electrotransformation of Corynebacterium pseudotuberculosis, testing variations of parameters in the procedures that are routinely used for the preparation of electrocompetent cells of this species, including (i) culture conditions, (ii) cell growth phase, (iii) electroporation solutions and (iv) quantity of plasmid DNA. We obtained the greatest efficiency of transformation when the cells were grown until the stationary phase and then washed with 10% glycerol electroporation solution. The transformation efficiency was inversely proportional to the quantity of plasmid DNA. The transformation efficiency reached 10(5) colony-forming units (cfu)/mug plasmid DNA. This protocol would be useful for genetic studies of C. pseudotuberculosis.