Modulation of the Biocatalytic Properties of a Novel Lipase from Psychrophilic Serratia sp. (USBA-GBX-513) by Different Immobilization Strategies.

In this work, the effect of different immobilization procedures on the properties of a lipase obtained from the extremophilic microorganism Serratia sp. USBA-GBX-513, which was isolated from Paramo soils of Los Nevados National Natural Park (Colombia), is reported. Different Shepharose beads were used: octyl-(OC), octyl-glyoxyl-(OC-GLX), cyanogen bromide (BrCN)-, and Q-Sepharose. The performance of the different immobilized extremophile lipase from Serratia (ESL) was compared with that of the lipase B from Candida antarctica (CALB). In all immobilization tests, hyperactivation of ESL was observed. The highest hyperactivation (10.3) was obtained by immobilization on the OC support. Subsequently, the thermal stability at pH 5, 7, and 9 and the stability in the presence of 50% (v/v) acetonitrile, 50% dioxane, and 50% tetrahydrofuran solvents at pH 7 and 40 °C were evaluated. ESL immobilized on octyl-Sepharose was the most stable biocatalyst at 90 °C and pH 9, while the most stable preparation at pH 5 was ESL immobilized on OC-GLX-Sepharose supports. Finally, in the presence of 50% (v/v) tetrahydrofuran (THF) or dioxane at 40 °C, ESL immobilized on OC-Sepharose was the most stable biocatalyst, while the immobilized preparation of ESL on Q-Sepharose was the most stable one in 40% (v/v) acetonitrile.

Salifodinibacter halophilus gen. nov., sp. nov., a halophilic gammaproteobacterium in the family Salinisphaeraceae isolated from a salt mine in the Colombian Andes.

Two morphologically similar halophilic strains, named USBA 874 and USBA 960T, were isolated from water and sediment samples collected from the Zipaquirá salt mine in the Colombian Andes. Both isolates had non-spore-forming, Gram-stain-negative and motile cells that grew aerobically. The strains grew optimally at 30 °C, pH 7.0 and with 25 % NaCl (w/v). The isolates showed almost identical 16S rRNA gene sequences (99.0 % similarity). The predominant quinones of USBA-960T were Q-8, Q-7 and Q-9. The major cellular fatty acids were C19 : 0 cyclo ω8c, C18 : 0 and C16 : 0. According to 16S rRNA gene sequencing, the closest phylogenetic relatives are Salinisphaera species (similarity between 93.6 and 92.3 %), Abyssibacter profundi OUC007T (88.6 %) and Oceanococcus atlanticus 22II-S10r2T (88.7 %). In addition, the result of genome blast distance phylogeny analysis between strains USBA 874 and USBA 960T, Salinisphaera halophila (YIM 95161T), Salinisphaera shabanensis (E1L3AT), Salinisphaera orenii (MK-B5T) and Salinisphaera japonica (YTM-1T) was 18.5 %. Other in silico species delineation analyses also showed low identity such as ANIb and ANIm values (<69.0 and <84.0 % respectively), TETRA (<0.81) and AAI values (<0.67). Genome sequencing of USBA 960T revealed a genome size of 2.47 Mbp and a G+C content of 59.71 mol%. Phylogenetic analysis of strains USBA 874 and USBA 960T indicated that they formed a different lineage within the family Salinisphaeraceae. Based on phenotypic and chemotaxonomic characteristics, phylogenetic analysis and DNA-DNA relatedness values, along with identity at whole genome level, it can be concluded that strains USBA 960T and USBA 874 represent a novel genus of the family Salinisphaeraceae and the name Salifodinibacter halophilus gen. nov., sp. nov. is proposed. The type strain is USBA 960T (CMPUJ U095T=CECT 30006T).

Bioactive Potential of Extracts of Labrenzia aggregata Strain USBA 371, a Halophilic Bacterium Isolated from a Terrestrial Source.

Previous studies revealed the potential of Labrenzia aggregata USBA 371 to produce cytotoxic metabolites. This study explores its metabolic diversity and compounds involved in its cytotoxic activity. Extracts from the extracellular fraction of strain USBA 371 showed high levels of cytotoxic activity associated with the production of diketopiperazines (DKPs). We purified two compounds and a mixture of two other compounds from this fraction. Their structures were characterized by 1D and 2D nuclear magnetic resonance (NMR). The purified compounds were evaluated for additional cytotoxic activities. Compound 1 (cyclo (l-Pro-l-Tyr)) showed cytotoxicity to the following cancer cell lines: breast cancer 4T1 (IC50 57.09 ± 2.11 µM), 4T1H17 (IC50 40.38 ± 1.94), MCF-7 (IC50 87.74 ± 2.32 µM), murine melanoma B16 (IC50 80.87 ± 3.67), human uterus sarcoma MES-SA/Dx5 P-pg (-) (IC50 291.32 ± 5.64) and MES-SA/Dx5 P-pg (+) (IC50 225.28 ± 1.23), and murine colon MCA 38 (IC50 29.85 ± 1.55). In order to elucidate the biosynthetic route of the production of DKPs and other secondary metabolites, we sequenced the genome of L. aggregata USBA 371. We found no evidence for biosynthetic pathways associated with cyclodipeptide synthases (CDPSs) or non-ribosomal peptides (NRPS), but based on proteogenomic analysis we suggest that they are produced by proteolytic enzymes. This is the first report in which the cytotoxic effect of cyclo (l-Pro-l-Tyr) produced by an organism of the genus Labrenzia has been evaluated against several cancer cell lines.

Colombian Andean thermal springs: reservoir of thermophilic anaerobic bacteria producing hydrolytic enzymes.

Anaerobic cultivable microbial communities in thermal springs producing hydrolytic enzymes were studied. Thermal water samples from seven thermal springs located in the Andean volcanic belt, in the eastern and central mountain ranges of the Colombian Andes were used as inocula for the growth and isolation of thermophilic microorganisms using substrates such as starch, gelatin, xylan, cellulose, Tween 80, olive oil, peptone and casamino acids. These springs differed in temperature (50-70 °C) and pH (6.5-7.5). The predominant ion in eastern mountain range thermal springs was sulphate, whereas that in central mountain range springs was bicarbonate. A total of 40 anaerobic thermophilic bacterial strains that belonged to the genera Thermoanaerobacter, Caloramator, Anoxybacillus, Caloranaerobacter, Desulfomicrobium, Geotoga, Hydrogenophilus, Desulfacinum and Thermoanaerobacterium were isolated. To investigate the metabolic potential of these isolates, selected strains were analysed for enzymatic activities to identify strains than can produce hydrolytic enzymes. We demonstrated that these thermal springs contained diverse microbial populations of anaerobic thermophilic comprising different metabolic groups of bacteria including strains belonging to the genera Thermoanaerobacter, Caloramator, Anoxybacillus, Caloranaerobacter, Desulfomicrobium, Geotoga, Hydrogenophilus, Desulfacinum and Thermoanaerobacterium with amylases, proteases, lipases, esterases, xylanases and pectinases; therefore, the strains represent a promising source of enzymes with biotechnological potential.

Draft genome and description of Consotaella salsifontis gen. nov. sp. nov., a halophilic, free-living, nitrogen-fixing alphaproteobacterium isolated from an ancient terrestrial saline spring.

A free-living, nitrogen-fixing, mesophilic and facultative aerobe, designated strain USBA 369T, was isolated from a terrestrial saline spring of the Colombian Andes. The non-sporulating rods (1.5×0.8 µm) with rounded ends stained Gram-negative and were motile by means of lophotrichous flagella. The strain grew optimally at 30 °C, at pH 6.9-7.5 and with 1.5 % (w/v) NaCl. The major fatty acids detected were C18 : 1ω7c and C19 : 0 cyclo ω8c, and the respiratory lipoquinone ubiquinone 10 (Q-10) was present. The genome consisted of 4.65 Mb with a DNA G+C content of 64.3 mol%. A total of 4371 genes were predicted and, of those, 4300 were protein coding genes and 71 were RNA genes. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain USBA 369T formed a different lineage within the class Alphaproteobacteria, order Rhizobiales, and DNA homology studies with the most closely related genera, Aurantimonas, Aureimonas and Rhizobium (95 % 16S rRNA gene sequence similarity), showed values of <15 %. The phylogenomic analysis provided evidence for clear phylogenetic divergence between strain USBA 369T and the closely related genera. On the basis of the phenotypic, chemotaxonomic and phylogenomic evidence, strain USBA 369T is considered to represent a novel genus and a novel species for which the name Consotaella salsifontis gen. nov., sp. nov. is proposed. The type strain is USBA 369T (=KCTC 22549T=CMPUJ U369T).

Mining lipolytic enzymes in community DNA from high Andean soils using a targeted approach.

Microbial enrichments cultures are a useful strategy to speed up the search for enzymes that can be employed in industrial processes. Lipases have gained special attention because they show unique properties such as: broad substrate specificity, enantio- and regio-selectivity and stability in organic solvents. A major goal is to identify novel lipolytic enzymes from microorganisms living in cold extreme environments such as high Andean soils, of relevance to our study being their capability be used in industrial processes. Paramo and glacier soils from the Nevados National Park in Colombia were sampled and microbial communities enriched through a fed-batch fermentation using olive oil as an inductor substrate. After 15 days of enrichment under aerobic conditions, total DNA was extracted. Subsequently, metagenomic libraries were constructed in the cosmid vector pWEB-TNC™. After functional screening, twenty and eighteen lipolytic clones were obtained from Paramo and Glacier soil enrichments, respectively. Based on lipid hydrolysis halo dimensions, the clone (Gla1) from a glacier enrichment was selected. A gene related to lipolytic activity was subcloned to evaluate enzyme properties. Phylogenetic analysis of the identified gene showed that the encoded lipase belongs to the family GDSL from a Ralstonia-like species. Interestingly, the secreted enzyme exhibited stability at high temperature and alkaline conditions, specifically the preferred conditions at 80 °C and pH 9.0. Thus, with the identification of an enzyme with non-expected properties, in this study is shown the potential of extreme cold environments to be explored for new catalytic molecules, using current molecular biology techniques, with applications in industrial processes, which demand stability under harsh conditions.

Assessment of brain metabolite correlates of adeno-associated virus-mediated over-expression of human alpha-synuclein in cortical neurons by in vivo (1) H-MR spectroscopy at 9.4 T.

In this study, we used proton-localized spectroscopy ((1) H-MRS) for the acquisition of the neurochemical profile longitudinally in a novel rat model of human wild-type alpha-synuclein (α-syn) over-expression. Our goal was to find out if the increased α-syn load in this model could be linked to changes in metabolites in the frontal cortex. Animals injected with AAV vectors encoding for human α-syn formed the experimental group, whereas green fluorescent protein expressing animals were used as the vector-treated control group and a third group of uninjected animals were used as naïve controls. Data were acquired at 2, 4, and 8 month time points. Nineteen metabolites were quantified in the MR spectra using LCModel software. On the basis of 92 spectra, we evaluated any potential gender effect and found that lactate (Lac) levels were lower in males compared to females, while the opposite was observed for ascorbate (Asc). Next, we assessed the effect of age and found increased levels of GABA, Tau, and GPC+PCho. Finally, we analyzed the effect of treatment and found that Lac levels (p = 0.005) were specifically lower in the α-syn group compared to the green fluorescent protein and control groups. In addition, Asc levels (p = 0.05) were increased in the vector-injected groups, whereas glucose levels remained unchanged. This study indicates that the metabolic switch between glucose-lactate could be detectable in vivo and might be modulated by Asc. No concomitant changes were found in markers of neuronal integrity (e.g., N-acetylaspartate) consistent with the fact that α-syn over-expression in cortical neurons did not result in neurodegeneration in this model. We acquired the neurochemical profile longitudinally in a rat model of human wild-type alpha-synuclein (α-syn) over-expression in cortical neurons. We found that Lactate levels were reduced in the α-syn group compared to the control groups and Ascorbate levels were increased in the vector-injected groups. No changes were found in markers of neuronal integrity consistent with the fact that α-syn over-expression did not result in frank neurodegeneration.

A novel thermoalkalostable esterase from Acidicaldus sp. strain USBA-GBX-499 with enantioselectivity isolated from an acidic hot springs of Colombian Andes.

Several thermo- and mesoacidophilic bacterial strains that revealed high lipolytic activity were isolated from water samples derived from acidic hot springs in Los Nevados National Natural Park (Colombia). A novel lipolytic enzyme named 499EST was obtained from the thermoacidophilic alpha-Proteobacterium Acidicaldus USBA-GBX-499. The gene estA encoded a 313-amino-acid protein named 499EST. The deduced amino acid sequence showed the highest identity (58 %) with a putative α/ß hydrolase from Acidiphilium sp. (ZP_08632277.1). Sequence alignments and phylogenetic analysis indicated that 499EST is a new member of the bacterial esterase/lipase family IV. The esterase reveals its optimum catalytic activity at 55 °C and pH 9.0. Kinetic studies showed that 499EST preferentially hydrolyzed middle-length acyl chains (C6-C8), especially p-nitrophenyl (p-NP) caproate (C6). Its thermostability and activity were strongly enhanced by adding 6 mM FeCl3. High stability in the presence of water-miscible solvents such as dimethyl sulfoxide and glycerol was observed. This enzyme also exhibits stability under harsh environmental conditions and enantioselectivity towards naproxen and ibuprofen esters, yielding the medically relevant (S)-enantiomers. In conclusion, according to our knowledge, 499EST is the first thermoalkalostable esterase derived from a Gram-negative thermoacidophilic bacterium.

Development of NMR spectroscopic methods for dynamic detection of acetylcholine synthesis by choline acetyltransferase in hippocampal tissue.

Choline acetyltransferase (ChAT) is the key enzyme for acetylcholine (ACh) synthesis and constitutes a reliable marker for the integrity of cholinergic neurons. Cortical ChAT activity is decreased in the brain of patients suffering from Alzheimer's and Parkinson's diseases. The standard method used to measure the activity of ChAT enzyme relies on a very sensitive radiometric assay, but can only be performed on post-mortem tissue samples. Here, we demonstrate the possibility to monitor ACh synthesis in rat brain homogenates in real time using NMR spectroscopy. First, the experimental conditions of the radiometric assay were carefully adjusted to produce maximum ACh levels. This was important for translating the assay to NMR, which has a low intrinsic sensitivity. We then used (15) N-choline and a pulse sequence designed to filter proton polarization by nitrogen coupling before (1) H-NMR detection. ACh signal was resolved from choline signal and therefore it was possible to monitor ChAT-mediated ACh synthesis selectively over time. We propose that the present approach using a labeled precursor to monitor the enzymatic synthesis of ACh in rat brain homogenates through real-time NMR represents a useful tool to detect neurotransmitter synthesis. This method may be adapted to assess the state of the cholinergic system in the brain in vivo in a non-invasive manner using NMR spectroscopic techniques.

Caloramator quimbayensis sp. nov., an anaerobic, moderately thermophilic bacterium isolated from a terrestrial hot spring.

An anaerobic, moderately thermophilic, terminal-spore-forming bacterium, designated strain USBA A(T), was isolated from a terrestrial hot spring located at an altitude of 2683 m in the Andean region of Colombia (04° 50' 14.0″ N 75° 32' 53.4″ W). Cells of strain USBA A(T) were Gram-stain-positive, straight to slightly curved rods (0.9×2.5 µm), that were arranged singly or in pairs, and were motile by means of flagella. Growth occurred at 37-55 °C and pH 6.0-8.0, with a doubling time of 2 h under the optimal conditions (50 °C and pH 7.0). Glucose fermentation in strain USBA A(T) required yeast extract or peptone (each at 0.2 %, w/v). The novel strain fermented sugars, amino acids, Casamino acids, propanol, propionate, starch and dextrin, but no growth was observed on galactose, lactose, xylose, histidine, serine, threonine, benzoate, butyrate, lactate, pyruvate, succinate, methanol, ethanol, glycerol, casein, gelatin or xylan. The end products of glucose fermentation were formate, acetate, ethanol and lactate. Strain USBA A(T) did not grow autotrophically (with CO2 as carbon source and H2 as electron donor) and did not reduce thiosulfate, sulfate, elemental sulfur, sulfite, vanadium (V) or Fe (III) citrate. Growth of strain USBA A(T) was inhibited by ampicillin, chloramphenicol, kanamycin, penicillin and streptomycin (each at 10 µg ml(-1)). The predominant fatty acids were iso-C15 : 0, C16 : 0 and iso-C17 : 0 and the genomic DNA G+C content was 32.6 mol%. 16S rRNA gene sequence analysis indicated that strain USBA A(T) belonged in the phylum Firmicutes and that its closest relative was Caloramator viterbiensis JW/MS-VS5(T) (95.0 % sequence similarity). A DNA-DNA relatedness value of only 30 % was recorded in hybridization experiments between strain USBA A(T) and Caloramator viterbiensis DSM 13723(T). Based on the phenotypic, chemotaxonomic and phylogenetic evidence and the results of the DNA-DNA hybridization experiments, strain USBA A(T) represents a novel species of the genus Caloramator, for which the name Caloramator quimbayensis sp. nov. is proposed. The type strain is USBA A(T) ( = CMPUJ U833(T)  = DSM 22093(T)).

In-depth characterization via complementing culture-independent approaches of the microbial community in an acidic hot spring of the Colombian Andes.

The microbial community of a Colombian high mountain hot spring, El Coquito, was analyzed using three different culture-independent assessments of 16S ribosomal RNA genes: clone libraries, pyrosequencing of the V5-V6 hypervariable region, and microarray. This acidic spring had a diverse community composed mainly of Bacteria that shared characteristics with those from other hot springs and extreme acidic environments. The microbial community was dominated by Proteobacteria, Firmicutes, and Planctomycetes and contained chemotrophic bacteria potentially involved in cycling of ferrous and sulfur-containing minerals and phototrophic organisms, most of which were eukaryotic micro-algae. Despite the presence of a large proportion of novel, unclassified sequences, the taxonomic profiles obtained with each strategy showed similarities at higher taxonomic levels. However, some groups, such as Spirochaetes and Aquificae, were identified using only one methodology, and more taxa were detected with the gene array, which also shared more groups with the pyrosequencing data. Overall, the combined use of different approaches provided a broader view of the microbial community in this acidic hot spring.

Taxonomic and functional assignment of cloned sequences from high Andean forest soil metagenome.

Total metagenomic DNA was isolated from high Andean forest soil and subjected to taxonomical and functional composition analyses by means of clone library generation and sequencing. The obtained yield of 1.7 µg of DNA/g of soil was used to construct a metagenomic library of approximately 20,000 clones (in the plasmid p-Bluescript II SK+) with an average insert size of 4 Kb, covering 80 Mb of the total metagenomic DNA. Metagenomic sequences near the plasmid cloning site were sequenced and them trimmed and assembled, obtaining 299 reads and 31 contigs (0.3 Mb). Taxonomic assignment of total sequences was performed by BLASTX, resulting in 68.8, 44.8 and 24.5% classification into taxonomic groups using the metagenomic RAST server v2.0, WebCARMA v1.0 online system and MetaGenome Analyzer v3.8 software, respectively. Most clone sequences were classified as Bacteria belonging to phlya Actinobacteria, Proteobacteria and Acidobacteria. Among the most represented orders were Actinomycetales (34% average), Rhizobiales, Burkholderiales and Myxococcales and with a greater number of sequences in the genus Mycobacterium (7% average), Frankia, Streptomyces and Bradyrhizobium. The vast majority of sequences were associated with the metabolism of carbohydrates, proteins, lipids and catalytic functions, such as phosphatases, glycosyltransferases, dehydrogenases, methyltransferases, dehydratases and epoxide hydrolases. In this study we compared different methods of taxonomic and functional assignment of metagenomic clone sequences to evaluate microbial diversity in an unexplored soil ecosystem, searching for putative enzymes of biotechnological interest and generating important information for further functional screening of clone libraries.

A novel cold active esterase derived from Colombian high Andean forest soil metagenome.

In order to search new lipolytic enzymes and conduct bioprospecting of microbial communities from high Andean forest soil, a metagenomic library of approximately 20,000 clones was constructed in Escherichia coli using plasmid p-Bluescript II SK+. The library covered 80 Mb of the metagenomic DNA mainly from Proteobacteria, Actinobacteria and Acidobacteria. Two clones with lipolytic activity in tributyrin as a substrate were recovered. Clone BAA3G2 (pSK-estGX1) was selected and the entire 4.6 Kb insert sequence was determined. The sequence had a GC content of 70.6% and could be derived from an undescribed Actinobacteria genome. One open reading frame encoded a polypeptide of 210 amino acids (gene estGX1) with a molecular mass of 22.4 kDa that contained the pentapeptide G-P-S-G-G near the N-terminus essential for lipase activity and the putative catalytic triad was identified, also a putative ribosomal binding site located 18 bp upstream the estGX1 ATG start codon was identified. The phylogenetic analysis suggested that the protein belonged to a new lipase family. The secreted enzyme showed a preference for short length fatty acids, with specific activity against p-nitrophenyl-butyrate (0.142 U/mg of total protein), it was cold active with relative activity of 30% at 10°C and moderately thermo active with relative activity of 80% at 50°C and had a pH optimum of 8.0 at 40°C.

One-year mortality after hip fracture surgery: urban-rural differences in the Colombian Andes.

To determine urban-rural differences influencing mortality in patients with hip fracture in Colombian Andes Mountains over a 1-year period. PURPOSE: To identify the urban-rural differences of sociodemographic variables, fracture-related characteristics, and preoperative and postoperative clinical factors associated with 1-year mortality in patients over 60 years old who underwent hip fracture surgery in the Andes Mountains. METHODS: A total of 126 patients with a fragility hip fracture during 2019-2020 were admitted to a tertiary care hospital. They were evaluated preoperatively and followed up until discharge. Those who survived were contacted by telephone at 1, 3, and 12 months. Univariate, bivariate, and Kaplan-Meier analyses with survival curves were performed. Relative risk was calculated with a 95% confidence interval. RESULTS: A total of 32.5% of the patients died within 1 year after surgery, with a significant difference between those who resided in rural areas (43.1%) and those who resided in urban areas (23.5%) (RR 1.70; 95% CI, 1.03 to 2.80, p = 0.036). In the multivariate analysis, anemia (hemoglobin level ≤ 9.0 g/dL during hospitalization) (RR 6.61; 95% CI, 1.49-29.37, p = 0.003), a blood transfusion requirement (RR 1.47; 95% CI, 1.07 to 2.01, p = 0.015), the type of fracture (subtrochanteric fracture (RR = 4.9, 95% CI = 1.418-16.943, p = 0.005)), and postoperative acute decompensation of chronic disease (RR 1.60; 95% CI, 1.01 to 2.53, p = 0.043) were found to be independent predictive factors of 1-year mortality after surgery. CONCLUSIONS: There was a difference in 1-year mortality between patients from rural and urban areas. More studies must be conducted to determine whether rurality behaves as an independent risk factor or is related to other variables, such as the burden of comorbidities and in-hospital complications.

Desulfosoma caldarium gen. nov., sp. nov., a thermophilic sulfate-reducing bacterium from a terrestrial hot spring.

A thermophilic, sulfate-reducing bacterium, designated strain USBA-053(T), was isolated from a terrestrial hot spring located at a height of 2500 m in the Colombian Andes (5° 45' 33.29″ N 73° 6' 49.89″ W), Colombia. Cells of strain USBA-053(T) were oval- to rod-shaped, Gram-negative and motile by means of a single polar flagellum. The strain grew autotrophically with H(2) as the electron donor and heterotrophically on formate, propionate, butyrate, valerate, isovalerate, lactate, pyruvate, ethanol, glycerol, serine and hexadecanoic acid in the presence of sulfate as the terminal electron acceptor. The main end products from lactate degradation, in the presence of sulfate, were acetate, CO(2) and H(2)S. Strain USBA-053(T) fermented pyruvate in the absence of sulfate and grew optimally at 57 °C (growth temperature ranged from 50 °C to 62 °C) and pH 6.8 (growth pH ranged from 5.7 to 7.7). The novel strain was slightly halophilic and grew in NaCl concentrations ranging from 5 to 30 g l(-1), with an optimum at 25 g l(-1) NaCl. Sulfate, thiosulfate and sulfite were used as electron acceptors, but not elemental sulfur, nitrate or nitrite. The G+C content of the genomic DNA was 56±1 mol%. 16S rRNA gene sequence analysis indicated that strain USBA-053(T) was a member of the class Deltaproteobacteria, with Desulfacinum hydrothermale MT-96(T) as the closest relative (93 % gene sequence similarity). On the basis of physiological characteristics and phylogenetic analysis, it is suggested that strain USBA-053(T) represents a new genus and novel species for which the name Desulfosoma caldarium gen. nov., sp. nov. is proposed. The type strain of the type species is USBA-053(T) ( = KCTC 5670(T) = DSM 22027(T)).

Production of Polyunsaturated Fatty Acids and Lipids from Autotrophic, Mixotrophic and Heterotrophic cultivation of Galdieria sp. strain USBA-GBX-832.

A search for extremophile organisms producing bioactive compounds led us to isolate a microalga identified as Galdieria sp. USBA-GBX-832 from acidic thermal springs. We have cultured Galdieria sp. USBA-GBX-832 under autotrophic, mixotrophic and heterotrophic conditions and determined variations of its production of biomass, lipids and PUFAs. Greatest biomass and PUFA production occurred under mixotrophic and heterotrophic conditions, but the highest concentration of lipids occurred under autotrophic conditions. Effects of variations of carbon sources and temperature on biomass and lipid production were evaluated and factorial experiments were used to analyze the effects of substrate concentration, temperature, pH, and organic and inorganic nitrogen on biomass production, lipids and PUFAs. Production of biomass and lipids was significantly dependent on temperature and substrate concentration. Greatest accumulation of PUFAs occurred at the lowest temperature tested. PUFA profiles showed trace concentrations of arachidonic acid (C20:4) and eicosapentaenoic acid (C20:5). This is the first time synthesis of these acids has been reported in Galdieria. These findings demonstrate that under heterotrophic conditions this microalga's lipid profile is significantly different from those observed in other species of this genus which indicates that the culture conditions evaluated are key determinants of these organisms' responses to stress conditions and accumulation of these metabolites.

Genome Sequences of Actinobacteria from Extreme Environments in Colombia.

We sequenced six actinobacterial genomes isolated from a salt mine and from soil in a high-mountain Páramo ecosystem. The strains belonged to the genera Streptomyces, Nesterenkonia, and Isoptericola and were sequenced due to their antimicrobial and cytotoxic activities.

Multivoxel 1H-MR Spectroscopy Biometrics for Preoprerative Differentiation Between Brain Tumors.

We investigated multivoxel proton magnetic resonance spectroscopy (1H-MRS) biometrics for preoperative differentiation and prognosis of patients with brain metastases (MET), low-grade glioma (LGG) and high-grade glioma (HGG). In total, 33 patients (HGG, 14; LGG, 9; and 10 MET) were included. 1H-MRS imaging (MRSI) data were assessed and neurochemical profiles for metabolites N-acetyl aspartate (NAA) + NAAG(NAA), Cr + PCr(total creatine, tCr), Glu + Gln(Glx), lactate (Lac), myo-inositol(Ins), GPC + PCho(total choline, tCho), and total lipids, and macromolecule (tMM) signals were estimated. Metabolites were reported as absolute concentrations or ratios to tCho or tCr levels. Voxels of interest in an MRSI matrix were labeled according to tissue. Logistic regression, receiver operating characteristic, and Kaplan-Meier survival analysis was performed. Across HGG, LGG, and MET, average Ins/tCho was shown to be prognostic for overall survival (OS): low values (≤1.29) in affected hemisphere predicting worse OS than high values (>1.29), (log rank < 0.007). Lip/tCho and Ins/tCho combined showed 100% sensitivity and specificity for both HGG/LGG (P < .001) and LGG/MET (P < .001) measured in nonenhancing/contrast-enhancing lesional tissue. Combining tCr/tCho in perilesional edema with tCho/tCr and NAA/tCho from ipsilateral normal- appearing tissue yielded 100% sensitivity and 81.8% specificity (P < .002) for HGG/MET. Best single biomarker: Ins/tCho for HGG/LGG and total lipid/tCho for LGG/MET showed 100% sensitivity and 75% and 100% specificity, respectively. HGG/MET; NAA/tCho showed 75% sensitivity and 84.6% specificity. Multivoxel 1H-MRSI provides prognostic information for OS for HGG/LGG/MET and a multibiometric approach for differentiation may equal or outperform single biometrics.

Correction to: Microbial diversity of saline environments: searching for cytotoxic activities.

The original version of this article (Diaz-Cardenas et al. 2017) unfortunately contained a mistake in Fig. 1. The pie chart of Fig. 1 should explain the distribution of the relative abundance of the Bacteria and Archaea strains isolated at Zipaquirá salt mine: Proteobacteria 39%; Actinobacteria 9%, Bacteroidetes 1%, Archaea 3% and Firmicutes 48% instead of NOMBRE DE CATEGORIA [PORCENTAJE]. The corrected Fig. 1 and caption are given below.

Microbial diversity of saline environments: searching for cytotoxic activities.

In order to select halophilic microorganisms as a source of compounds with cytotoxic activities, a total of 135 bacterial strains were isolated from water and sediment samples collected from the Zipaquirá salt mine in the Colombian Andes. We determined the cytotoxic effects of 100 crude extracts from 54 selected organisms on the adherent murine mammary cell carcinoma 4T1 and human mammary adenocarcinoma MCF-7 cell lines. These extracts were obtained from strains of Isoptericola, Ornithinimicrobium, Janibacter, Nesterenkonia, Alkalibacterium, Bacillus, Halomonas, Chromohalobacter, Shewanella, Salipiger, Martellela, Oceanibaculum, Caenispirillum and Labrenzia. The extracts of 23 strains showed an IC50 of less than 100 µg mL-1. They were subsequently analyzed by LC/MS allowing dereplication of 20 compounds. The cytotoxic effect was related to a complex mixture of diketopiperazines present in many of the extracts analyzed. The greatest cytotoxic activity against both of the evaluated cell lines was obtained from the chloroform extract of Labrenzia aggregata USBA 371 which had an IC50 < 6 µg mL-1. Other extracts with high levels of cytotoxic activity were obtained from Bacillus sp. (IC50 < 50 µg mL-1) which contained several compounds such as macrolactin L and A, 7-O-succinoylmacrolactin F and iturin. Shewanella chilikensis USBA 344 also showed high levels of cytotoxic activity against both cell lines in the crude extract: an IC50 < 15 µg mL-1 against the 4T1 cell line and an IC50 < 68 µg mL-1 against the MCF-7 cell line. Nesterenkonia sandarakina CG 35, which has an IC50 of 118 µg mL-1 against 4T1, is a producer of diketopiperazines and 1-acetyl-ß-carboline. Also, Ornithinimicrobium kibberense CG 24, which has IC50 < 50 µg mL-1, was a producer of diketopiperazines and lagunamycin. Our study demonstrates that these saline environments are habitats of halophilic and halotolerant bacteria that have previously unreported cytotoxic activity.