PubMed

Baicalein protects PC12 cells from Aβ25-35-induced cytotoxicity via inhibition of apoptosis and metabolic disorders. Life Sci. 2020 Feb 26;:117471 Authors: Gao L, Zhou F, Wang KX, Zhou YZ, Du GH, Qin XM Abstract AIMS: This study aimed to explore the protective effects and possible mechanisms of baicalein on Aβ25-35-induced toxicity. MAIN METHODS: Thioflavin-T (Th-T) dye was used to determine the effects of baicalein on Aβ25-35 aggregation in vitro. PC12 cells were stimulated with Aβ25-35, then the effects of baicalein on apoptosis, mitochondrial membrane potential (MMP), adenosine triphosphate (ATP), mitochondrial respiratory complex I, reactive oxygen species (ROS) and nitric oxide (NO) levels were determined. Moreover, LC-MS metabolomics approach was used to detect metabolic changes induced by baicalein in Aβ25-35-injured PC12 cells. KEY FINDINGS: The results showed that baicalein could inhibit the aggregation of Aβ25-35 in vitro. Furthermore, pretreatment with baicalein significantly prevented Aβ25-35-induced cell apoptosis, as manifested by increasing the levels of MMP, ATP and mitochondrial respiratory complex I, decreasing the contents of ROS and NO. LC-MS metabolomics revealed that baicalein can regulate 5 metabolites, mainly involving two metabolic pathways, arginine and proline metabolism, nicotinate and nicotinamide metabolism. SIGNIFICANCE: Our study revealed that baicalein has a protective effect on Aβ25-35-induced neurotoxicity in PC12 cells, which may be related to inhibition of apoptosis and metabolic disorders. PMID: 32112868 [PubMed - as supplied by publisher]

Related Articles A UV-B-responsive glycosyltransferase, OsUGT706C2, modulates flavonoid metabolism in rice. Sci China Life Sci. 2020 Feb 25;: Authors: Zhang F, Guo H, Huang J, Yang C, Li Y, Wang X, Qu L, Liu X, Luo J Abstract Although natural variations in rice flavonoids exist, and biochemical characterization of a few flavonoid glycosyltransferases has been reported, few studies focused on natural variations in tricin-lignan-glycosides and their underlying genetic basis. In this study, we carried out metabolic profiling of tricin-lignan-glycosides and identified a major quantitative gene annotated as a UDP-dependent glycosyltransferase OsUGT706C2 by metabolite-based genome-wide association analysis. The putative flavonoid glycosyltransferase OsUGT706C2 was characterized as a flavonoid 7-O-glycosyltransferas in vitro and in vivo. Although the in vitro enzyme activity of OsUGT706C2 was similar to that of OsUGT706D1, the expression pattern and induced expression profile of OsUGT706C2 were very different from those of OsUGT706D1. Besides, OsUGT706C2 was specifically induced by UV-B. Constitutive expression of OsUGT706C2 in rice may modulate phenylpropanoid metabolism at both the transcript and metabolite levels. Furthermore, overexpressing OsUGT706C2 can enhance UV-B tolerance by promoting ROS scavenging in rice. Our findings might make it possible to use the glycosyltransferase OsUGT706C2 for crop improvement with respect to UV-B adaptation and/or flavonoid accumulation, which may contribute to stable yield. PMID: 32112268 [PubMed - as supplied by publisher]

Related Articles Haploid genetic screens identify SPRING/C12ORF49 as a determinant of SREBP signaling and cholesterol metabolism. Nat Commun. 2020 Feb 28;11(1):1128 Authors: Loregger A, Raaben M, Nieuwenhuis J, Tan JME, Jae LT, van den Hengel LG, Hendrix S, van den Berg M, Scheij S, Song JY, Huijbers IJ, Kroese LJ, Ottenhoff R, van Weeghel M, van de Sluis B, Brummelkamp T, Zelcer N Abstract The sterol-regulatory element binding proteins (SREBP) are central transcriptional regulators of lipid metabolism. Using haploid genetic screens we identify the SREBP Regulating Gene (SPRING/C12ORF49) as a determinant of the SREBP pathway. SPRING is a glycosylated Golgi-resident membrane protein and its ablation in Hap1 cells, Hepa1-6 hepatoma cells, and primary murine hepatocytes reduces SREBP signaling. In mice, Spring deletion is embryonic lethal yet silencing of hepatic Spring expression also attenuates the SREBP response. Mechanistically, attenuated SREBP signaling in SPRINGKO cells results from reduced SREBP cleavage-activating protein (SCAP) and its mislocalization to the Golgi irrespective of the cellular sterol status. Consistent with limited functional SCAP in SPRINGKO cells, reintroducing SCAP restores SREBP-dependent signaling and function. Moreover, in line with the role of SREBP in tumor growth, a wide range of tumor cell lines display dependency on SPRING expression. In conclusion, we identify SPRING as a previously unrecognized modulator of SREBP signaling. PMID: 32111832 [PubMed - as supplied by publisher]

Related Articles Bacterial glycogen provides short-term benefits in changing environments. Appl Environ Microbiol. 2020 Feb 28;: Authors: Sekar K, Linker SM, Nguyen J, Grünhagen A, Stocker R, Sauer U Abstract Changing nutritional conditions challenge microbes and shape their evolutionary optimization. Here we investigated the role of glycogen in dynamic physiological adaptation of Escherichia coli to fluctuating nutrients following carbon starvation using real-time metabolomics. We found significant metabolic activity remaining after the depletion of environmental glucose that was linked to a rapid utilization of intracellular glycogen. Glycogen was depleted by 80% within minutes of glucose starvation and similarly replenished within minutes of glucose availability. These fast timescales of glycogen utilization correspond to the short-term benefits that glycogen provided to cells undergoing various physiological transitions. Cells capable of utilizing glycogen exhibited shorter lag times than glycogen mutants when starved between different carbon sources. The ability to utilize glycogen was also important for the transition between planktonic and biofilm lifestyles and enabled increased glucose uptake during pulses of limited glucose availability. While wild-type and mutant strains exhibited comparable growth rates in steady environments, mutants deficient in glycogen utilization grew more poorly in environments that fluctuated on minute-scales between carbon availability and starvation. Altogether, these results highlight an underappreciated role of glycogen to rapidly provide carbon and energy in changing environments, thereby increasing survival and competition capabilities in fluctuating and nutrient poor conditions.ImportanceNothing is constant in life and microbes in particular have to adapt to frequent and rapid environmental changes. Here we demonstrate that the internal storage polymer glycogen plays a crucial role for such dynamic adaptations by using real-time metabolomics and single cell imaging. Glycogen depletes within minutes of glucose starvation and similarly replenishes within minutes of glucose availability. Cells capable of utilizing glycogen exhibited shorter lag times than glycogen mutants when starved between different carbon sources. While wild- type and mutant strains exhibited comparable growth rates in steady environments, mutants deficient in glycogen utilization grew more poorly in environments that fluctuated on minute- scales between carbon availability and starvation. These results highlight an underappreciated role of glycogen to rapidly provide carbon and energy in changing environments, thereby increasing survival and competition capabilities in fluctuating and nutrient poor conditions. PMID: 32111592 [PubMed - as supplied by publisher]

Related Articles Enterotype identification and its influence on regulating the duodenum metabolism in chickens. Poult Sci. 2020 Mar;99(3):1515-1527 Authors: Yuan Z, Yan W, Wen C, Zheng J, Yang N, Sun C Abstract Enterotypes are used to describe clusters of specific gut microbial community structures, but few reports exist on the identification of enterotypes in poultry. In addition, there is incomplete understanding on the role of the foregut microbiota in the digestion and absorption of nutrients in poultry. Thus, this study aimed to identify the duodenal enterotypes by examining microbial communities from 206 broilers using 16S rRNA high-throughput sequencing and explore the effects of enterotypes on phenotypic performance and nutrient metabolism with metabolomics. The duodenal microbial communities of the broiler population were partitioned into 3 enterotypes (ET1, ET2, and ET3), and significant differences were observed in α-diversity among the enterotypes (P < 0.01). At the genus level, the ET1 group was over-represented by Bacteroides (9.8%) and Escherichia-Shigella (8.9%), the ET2 group was over-represented by Ochrobactrum (19.4%) and Rhodococcus (14.7%), and the ET3 group was over-represented by Bacillus (23.4%) and Akkermansia (16.2%). The relative abundance of the dominant taxa of each enterotype was significantly higher than that in the other 2 enterotypes (P < 0.01). The results showed that Ochrobactrum and Rhodococcus were positively correlated with cellobiose, alpha-D-glucose, D-mannose, and D-allose (r = 0.429, 0.435, 0.482, and 0.562, respectively; all P < 0.05). Rhodococcus was also positively correlated with tridecanoic acid and glycerol 1-myristate (r = 0.655 and 0.489, respectively; all P < 0.01). In terms of phenotype, the triglyceride level in the ET2 group was significantly higher than that in the ET1 group (P < 0.05), and the subcutaneous fat thickness and abdominal fat weight in the ET2 group were the highest (P > 0.05). Taken together, these results confirmed the presence of enterotypes in broilers and found that the dominant microbes in broilers of the ET2 group might play a major role in the degradation and utilization of plant polysaccharides, which may have an impact on the serum triglyceride level and fat deposition in broilers. These findings lay a foundation for further studies on the gut microbial interactions with the metabolism in broilers and the regulation of the gut microbiota to promote growth and well-being in broilers. PMID: 32111319 [PubMed - as supplied by publisher]

Related Articles A snapshot of microbial diversity and function in an undisturbed sugarcane bagasse pile. BMC Biotechnol. 2020 Feb 28;20(1):12 Authors: Gebbie L, Dam TT, Ainscough R, Palfreyman R, Cao L, Harrison M, O'Hara I, Speight R Abstract BACKGROUND: Sugarcane bagasse is a major source of lignocellulosic biomass, yet its economic potential is not fully realised. To add value to bagasse, processing is needed to gain access to the embodied recalcitrant biomaterials. When bagasse is stored in piles in the open for long periods it is colonised by microbes originating from the sugarcane, the soil nearby or spores in the environment. For these microorganisms to proliferate they must digest the bagasse to access carbon for growth. The microbial community in bagasse piles is thus a potential resource for the discovery of useful and novel microbes and industrial enzymes. We used culturing and metabarcoding to understand the diversity of microorganisms found in a uniquely undisturbed bagasse storage pile and screened the cultured organisms for fibre-degrading enzymes. RESULTS: Samples collected from 60 to 80 cm deep in the bagasse pile showed hemicellulose and partial lignin degradation. One hundred and four microbes were cultured from different layers and included a high proportion of oleaginous yeast and biomass-degrading fungi. Overall, 70, 67, 70 and 57% of the microbes showed carboxy-methyl cellulase, xylanase, laccase and peroxidase activity, respectively. These percentages were higher in microbes selectively cultured from deep layers, with all four activities found for 44% of these organisms. Culturing and amplicon sequencing showed that there was less diversity and therefore more selection in the deeper layers, which were dominated by thermophiles and acid tolerant organisms, compared with the top of pile. Amplicon sequencing indicated that novel fungi were present in the pile. CONCLUSIONS: A combination of culture-dependent and independent methods was successful in exploring the diversity in the bagasse pile. The variety of species that was found and that are known for biomass degradation shows that the bagasse pile was a valuable selective environment for the identification of new microbes and enzymes with biotechnological potential. In particular, lignin-modifying activities have not been reported previously for many of the species that were identified, suggesting future studies are warranted. PMID: 32111201 [PubMed - as supplied by publisher]

Related Articles Untargetted Metabolomic Exploration of the Mycobacterium tuberculosis Stress Response to Cinnamon Essential Oil. Biomolecules. 2020 Feb 26;10(3): Authors: Sieniawska E, Sawicki R, Golus J, Georgiev MI Abstract The antimycobacterial activity of cinnamaldehyde has already been proven for laboratory strains and for clinical isolates. What is more, cinnamaldehyde was shown to threaten the mycobacterial plasma membrane integrity and to activate the stress response system. Following promising applications of metabolomics in drug discovery and development we aimed to explore the mycobacteria response to cinnamaldehyde within cinnamon essential oil treatment by untargeted liquid chromatography-mass spectrometry. The use of predictive metabolite pathway analysis and description of produced lipids enabled the evaluation of the stress symptoms shown by bacteria. This study suggests that bacteria exposed to cinnamaldehyde could reorganize their outer membrane as a physical barrier against stress factors. They probably lowered cell wall permeability and inner membrane fluidity, and possibly redirected carbon flow to store energy in triacylglycerols. Being a reactive compound, cinnamaldehyde may also contribute to disturbances in bacteria redox homeostasis and detoxification mechanisms. PMID: 32111061 [PubMed - as supplied by publisher]

Related Articles Metabolomics Analysis Reveals the Alkali Tolerance Mechanism in Puccinellia tenuiflora Plants Inoculated with Arbuscular Mycorrhizal Fungi. Microorganisms. 2020 Feb 26;8(3): Authors: Yang C, Zhao W, Wang Y, Zhang L, Huang S, Lin J Abstract Soil alkalization is a major environmental threat that affects plant distribution and yield in northeastern China. Puccinellia tenuiflora is an alkali-tolerant grass species that is used for salt-alkali grassland restoration. However, little is known about the molecular mechanisms by which arbuscular mycorrhizal fungi (AMF) enhance P. tenuiflora responses to alkali stress. Here, metabolite profiling in P. tenuiflora seedlings with or without arbuscular mycorrhizal fungi (AMF) under alkali stress was conducted using liquid chromatography combined with time-of-flight mass spectrometry (LC/TOF-MS). The results showed that AMF colonization increased seedling biomass under alkali stress. In addition, principal component analysis (PCA) and orthogonal projections to latent structures discriminant analysis (OPLS-DA) demonstrated that non-AM and AM seedlings showed different responses under alkali stress. A heat map analysis showed that the levels of 88 metabolites were significantly changed in non-AM seedlings, but those of only 31 metabolites were significantly changed in AM seedlings. Moreover, the levels of a total of 62 metabolites were significantly changed in P. tenuiflora seedlings after AMF inoculation. The results suggested that AMF inoculation significantly increased amino acid, organic acid, flavonoid and sterol contents to improve osmotic adjustment and maintain cell membrane stability under alkali stress. P. tenuiflora seedlings after AMF inoculation produced more plant hormones (salicylic acid and abscisic acid) than the non-AM seedlings, probably to enhance the antioxidant system and facilitate ion balance under stress conditions. In conclusion, these findings provide new insights into the metabolic mechanisms of P. tenuiflora seedlings with arbuscular mycorrhizal fungi under alkali conditions and clarify the role of AM in the molecular regulation of this species under alkali stress. PMID: 32110985 [PubMed - as supplied by publisher]

Related Articles Metabolic Profiling of Glucose-Fed Metabolically Active Resting Zymomonas mobilis Strains. Metabolites. 2020 Feb 26;10(3): Authors: Fuchino K, Kalnenieks U, Rutkis R, Grube M, Bruheim P Abstract Zymomonas mobilis is the most efficient bacterial ethanol producer and its physiology is potentially applicable to industrial-scale bioethanol production. However, compared to other industrially important microorganisms, the Z. mobilis metabolome and adaptation to various nutritional and genetic perturbations have been poorly characterized. For rational metabolic engineering, it is essential to understand how central metabolism and intracellular redox balance are maintained in Z. mobilis under various conditions. In this study, we applied quantitative mass spectrometry-based metabolomics to explore how glucose-fed non-growing Z. mobilis Zm6 cells metabolically adapt to change of oxygen availability. Mutants partially impaired in ethanol synthesis (Zm6 adhB) or oxidative stress response (Zm6 cat) were also examined. Distinct patterns of adaptation of central metabolite pools due to the change in cultivation condition and between the mutants and Zm6 reference strain were observed. Decreased NADH/NAD ratio under aerobic incubation corresponded to higher concentrations of the phosphorylated glycolytic intermediates, in accordance with predictions of the kinetic model of Entner-Doudoroff pathway. The effects on the metabolite pools of aerobic to anaerobic transition were similar in the mutants, yet less pronounced. The present data on metabolic plasticity of non-growing Z. mobilis cells will facilitate the further metabolic engineering of the respective strains and their application as biocatalysts. PMID: 32110884 [PubMed - as supplied by publisher]

20 new pubmed citations were retrieved for your search. Click on the search hyperlink below to display the complete search results: metabolomics These pubmed results were generated on 2020/02/29PubMed comprises more than millions of citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.

27 new pubmed citations were retrieved for your search. Click on the search hyperlink below to display the complete search results: metabolomics These pubmed results were generated on 2020/02/28PubMed comprises more than millions of citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.

23 new pubmed citations were retrieved for your search. Click on the search hyperlink below to display the complete search results: metabolomics These pubmed results were generated on 2020/02/27PubMed comprises more than millions of citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.

33 new pubmed citations were retrieved for your search. Click on the search hyperlink below to display the complete search results: metabolomics These pubmed results were generated on 2020/02/26PubMed comprises more than millions of citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.

Related Articles Synthesis, biochemical, pharmacological characterization and in silico profile modelling of highly potent opioid orvinol and thevinol derivatives. Eur J Med Chem. 2020 Feb 15;191:112145 Authors: Szűcs E, Marton J, Szabó Z, Hosztafi S, Kékesi G, Tuboly G, Bánki L, Horváth G, Szabó PT, Tömböly C, Varga ZK, Benyhe S, Ötvös F Abstract Morphine and its derivatives play inevitably important role in the μ-opioid receptor (MOR) targeted antinociception. A structure-activity relationship study is presented for novel and known orvinol and thevinol derivatives with varying 3-O, 6-O, 17-N and 20-alkyl substitutions starting from agonists, antagonists and partial agonists. In vitro competition binding experiments with [3H]DAMGO showed low subnanomolar affinity to MOR. Generally, 6-O-demethylation increased the affinity toward MOR and decreased the efficacy changing the pharmacological profile in some cases. In vivo tests in osteoarthritis inflammation model showed significant antiallodynic effects of thevinol derivatives while orvinol derivatives did not. The pharmacological character was modelled by computational docking to both active and inactive state models of MOR. Docking energy difference for the two states separates agonists and antagonists well while partial agonists overlapped with them. An interaction pattern of the ligands, involving the interacting receptor atoms, showed more efficient separation of the pharmacological profiles. In rats, thevinol derivatives showed antiallodynic effect in vivo. The orvinol derivatives, except for 6-O-desmethyl-dihydroetorfin (2c), did not show antiallodynic effect. PMID: 32092588 [PubMed - as supplied by publisher]

Related Articles Metabolomic, functional, and ecologic responses of the common freshwater fungus Neonectria lugdunensis to mine drainage stress. Sci Total Environ. 2020 Feb 16;718:137359 Authors: Seena S, Sobral O, Cano A Abstract Metal contamination of watersheds is a global problem. Here, we conducted litter decomposition studies with Neonectria lugdunensis, a cosmopolitan aquatic fungus. Fungal isolates from four reference (non-impacted) and six metal-contaminated streams (due to mine drainage) were exposed to mine drainage and reference stream waters in Central Portugal. Impact of mine drainage waters on N. lugdunensis hyphae was investigated by performing metabolomic profiling of 200 lipids and 25 amino acids (AA) with ultra-high performance liquid chromatography-mass spectrometry. In parallel, functional response of N. lugdunensis isolates was assessed through expression profiles of a functional gene, cellobiohydrolase I (CbhI). Ecological performance via leaf mass loss was also determined. Exposure to mine drainage waters altered the concentration of numerous AA and lipids. Most strikingly, a gradual increase in the concentration of the triacylglycerols (TAG) with shorter acyl chains and lesser unsaturation was observed after the exposure to mine drainage waters. In addition, the changes in the concentration of numerous TAG, lysophosphatidylcholines, and AA were more significant in the isolates from the metal-contaminated streams after exposure to mine drainage water. CbhI gene of the isolates from reference streams was down-regulated by metal stress, while those from metal-contaminated streams remained unaffected. Finally, leaf mass loss was influenced by both exposure to mine drainage waters and the origin of isolates. Overall, our study demonstrates unique functional signatures displayed by fungi under metal stress and the relevant role that fungal AA and lipids play to cope with metal toxicity. PMID: 32092520 [PubMed - as supplied by publisher]

Related Articles High-Throughput Screening for Engineered Nanoparticles That Enhance Photosynthesis Using Mesophyll Protoplasts. J Agric Food Chem. 2020 Feb 24;: Authors: Wang A, Jin Q, Xu X, Miao AJ, White JC, Gardea-Torresdey JL, Ji R, Zhao L Abstract Certain engineered nanoparticles (NPs) have unique properties that have exhibited significant potential for promoting photosynthesis and enhancing crop productivity. Understanding the fundamental interactions between NPs and plants is crucial for the sustainable development of nano-enabled agriculture. Leaf mesophyll protoplasts, which maintain similar physiological response and cellular activity as intact plants, were selected as model system to study the impact of NPs on photosynthesis. The mesophyll protoplasts isolated from spinach were cultivated with different NMs (Fe, Mn3O4, SiO2, Ag, and MoS2) dosing at 50 mg/L for 2 hours under illumination. The potential maximum quantum yield and adenosine triphosphate (ATP) production of mesophyll protoplasts were significantly increased by Mn3O4 and Fe NPs (23% and 43%, respectively), and were decreased by Ag and MoS2 NPs. The mechanism for the photosynthetic enhancement by Mn3O4 and Fe is to increase the photocurrent and electron transfer rate, as revealed by photoelectrochemical measurement. GC-MS based single cell type metabolomics reveal that NPs (Fe and MoS2) altered the metabolic profiles of mesophyll cells during 2 hours of illumination period. Separately, the effect of NPs exposure on photosynthesis and biomass were also conducted at the whole plant level. A strong correlation was observed with protoplast data; plant biomass was significantly increased by Mn3O4 exposure (57%) but was decreased (24%) by treatment of Ag NPs. The use of mesophyll protoplasts can be a fast and reliable tool for screening NPs to enhance photosynthesis for potential nanofertilizer use. Importantly, inclusion of a metabolic analysis can provide mechanistic toxicity data to ensure the development "safer-by-design" nano-enabled platforms. PMID: 32091884 [PubMed - as supplied by publisher]

Related Articles Transcriptomic and metabolomic profiling of long-lived growth hormone releasing hormone knock-out mice: evidence for altered mitochondrial function and amino acid metabolism. Aging (Albany NY). 2020 Feb 23;12: Authors: Hoffman JM, Poonawalla A, Icyuz M, Swindell WR, Wilson L, Barnes S, Sun LY Abstract Numerous genetic manipulations that extend lifespan in mice have been discovered over the past two decades, the most robust of which has arguably been the down regulation of growth hormone (GH) signaling. However, while decreased GH signaling has been associated with improved health and lifespan, many of the underlying physiological changes and molecular mechanisms associated with GH signaling have yet to be elucidated. To this end, we have completed the first transcriptomic and metabolomic study on long-lived growth hormone releasing hormone knockout (GHRH-KO) and wild-type mice in brown adipose tissue (transcriptomics) and blood serum (metabolomics). We find that GHRH-KO mice have increased transcript levels of mitochondrial and amino acid genes with decreased levels of extracellular matrix genes. Concurrently, mitochondrial metabolites are differentially regulated in GHRH-KO. Furthermore, we find a strong signal of genotype-by-sex interactions, suggesting the sexes have differing physiological responses to GH deficiency. Overall, our results point towards a strong influence of mitochondrial metabolism in GHRH-KO mice which potentially is tightly intertwined with their extended lifespan phenotype. PMID: 32091406 [PubMed - as supplied by publisher]

Related Articles Identification to species level of live single microalgal cells from plankton samples with matrix-free laser/desorption ionization mass spectrometry. Metabolomics. 2020 Feb 24;16(3):28 Authors: Baumeister TUH, Vallet M, Kaftan F, Guillou L, Svatoš A, Pohnert G Abstract INTRODUCTION: Marine planktonic communities are complex microbial consortia often dominated by microscopic algae. The taxonomic identification of individual phytoplankton cells usually relies on their morphology and demands expert knowledge. Recently, a live single-cell mass spectrometry (LSC-MS) pipeline was developed to generate metabolic profiles of microalgae. OBJECTIVE: Taxonomic identification of diverse microalgal single cells from collection strains and plankton samples based on the metabolic fingerprints analyzed with matrix-free laser desorption/ionization high-resolution mass spectrometry. METHODS: Matrix-free atmospheric pressure laser-desorption ionization mass spectrometry was performed to acquire single-cell mass spectra from collection strains and prior identified environmental isolates. The computational identification of microalgal species was performed by spectral pattern matching (SPM). Three similarity scores and a bootstrap-derived confidence score were evaluated in terms of their classification performance. The effects of high and low-mass resolutions on the classification success were evaluated. RESULTS: Several hundred single-cell mass spectra from nine genera and nine species of marine microalgae were obtained. SPM enabled the identification of single cells at the genus and species level with high accuracies. The receiver operating characteristic (ROC) curves indicated a good performance of the similarity measures but were outperformed by the bootstrap-derived confidence scores. CONCLUSION: This is the first study to solve taxonomic identification of microalgae based on the metabolic fingerprints of the individual cell using an SPM approach. PMID: 32090296 [PubMed - in process]

Related Articles Untargeted metabolomics links glutathione to bacterial cell cycle progression. Nat Metab. 2020 Feb;2(2):153-166 Authors: Hartl J, Kiefer P, Kaczmarczyk A, Mittelviefhaus M, Meyer F, Vonderach T, Hattendorf B, Jenal U, Vorholt JA Abstract Cell cycle progression requires the coordination of cell growth, chromosome replication, and division. Consequently, a functional cell cycle must be coupled with metabolism. However, direct measurements of metabolome dynamics remained scarce, in particular in bacteria. Here, we describe an untargeted metabolomics approach with synchronized Caulobacter crescentus cells to monitor the relative abundance changes of ~400 putative metabolites as a function of the cell cycle. While the majority of metabolite pools remains homeostatic, ~14% respond to cell cycle progression. In particular, sulfur metabolism is redirected during the G1-S transition, and glutathione levels periodically change over the cell cycle with a peak in late S phase. A lack of glutathione perturbs cell size by uncoupling cell growth and division through dysregulation of KefB, a K+/H+ antiporter. Overall, we here describe the impact of the C. crescentus cell cycle progression on metabolism, and in turn relate glutathione and potassium homeostasis to timely cell division. PMID: 32090198 [PubMed]

Related Articles Bioactive characteristics of a semi-hard non-starter culture cheese made from raw or pasteurized sheep's milk. 3 Biotech. 2020 Mar;10(3):85 Authors: Saidi V, Sheikh-Zeinoddin M, Kobarfard F, Soleimanian-Zad S Abstract In this study, the effect of pasteurization and use of starter cultures on physicochemical, microbiological and functional properties of a traditional Iranian semi-hard cheese (Lighvan cheese) was evaluated during stages of ripening (1, 60, 120 days). Profiles of polar metabolites were analyzed by gas-chromatography mass-spectrometry (GC-MS). Considerable free amino acids such as gamma-aminobutyric acid (GABA) were found in samples that have higher microbial communities i.e. raw sheep's milk without use of starter cultures and pasteurized sheep's milk cheese with co-culture. However, GABA was not found in pasteurized sheep's milk cheese without starter culture during ripening. Conclusively, the application of the starter culture could reduce the ripening time of sheep's milk cheese and could be an appropriate approach to increase the functionality of the sheep's milk cheese. PMID: 32089980 [PubMed]