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Genetics May 1974Methods are described for the isolation, complementation and mapping of mutants of Caenorhabditis elegans, a small free-living nematode worm. About 300 EMS-induced...
Methods are described for the isolation, complementation and mapping of mutants of Caenorhabditis elegans, a small free-living nematode worm. About 300 EMS-induced mutants affecting behavior and morphology have been characterized and about one hundred genes have been defined. Mutations in 77 of these alter the movement of the animal. Estimates of the induced mutation frequency of both the visible mutants and X chromosome lethals suggests that, just as in Drosophila, the genetic units in C. elegans are large.
Topics: Animals; Chromosome Mapping; Crosses, Genetic; Female; Genes, Lethal; Genetic Complementation Test; Genetic Linkage; Genetics, Behavioral; Male; Mesylates; Movement; Mutation; Nematoda; Nervous System Physiological Phenomena; Phenotype; Recombination, Genetic; Reproduction; Sex Chromosomes
PubMed: 4366476
DOI: 10.1093/genetics/77.1.71 -
Molecules (Basel, Switzerland) Jul 2020Superelectrophiles are reactive species that often carry multiple positive charges. They have been useful in numerous synthetic methods and they often exhibit highly... (Review)
Review
Superelectrophiles are reactive species that often carry multiple positive charges. They have been useful in numerous synthetic methods and they often exhibit highly unusual reactivities. Recent advances in superelectrophile chemistry are discussed in this review.
Topics: Aza Compounds; Cyclization; Electrochemistry; Mesylates; Quinolones
PubMed: 32707680
DOI: 10.3390/molecules25143281 -
Science (New York, N.Y.) Nov 2021To date, it remains challenging to selectively migrate a carbonyl oxygen within a given molecular scaffold, especially to an adjacent carbon. In this work, we describe a...
To date, it remains challenging to selectively migrate a carbonyl oxygen within a given molecular scaffold, especially to an adjacent carbon. In this work, we describe a simple one- or two-pot protocol that transposes a ketone to the vicinal carbon. This approach first converts the ketone to the corresponding alkenyl triflate, which can then undergo the palladium- and norbornene-catalyzed regioselective α-amination and ipso-hydrogenation enabled by a bifunctional hydrogen and nitrogen donor. The resulting “transposed enamine” intermediate can subsequently be hydrolyzed to produce the 1,2-carbonyl–migrated product. This method allows rapid access to unusual bioactive analogs through late-stage functionalization.
Topics: Amination; Carbon; Catalysis; Chemistry, Pharmaceutical; Hydrogen; Hydrogenation; Ketones; Mesylates; Molecular Structure; Norbornanes; Oxygen; Palladium; Technology, Pharmaceutical
PubMed: 34735246
DOI: 10.1126/science.abl7854 -
International Journal of Environmental... Mar 2022One of the most promising avenues of biofuel research relates to using waste as a starting feedstock to produce liquid or gaseous energy carriers. The global production...
One of the most promising avenues of biofuel research relates to using waste as a starting feedstock to produce liquid or gaseous energy carriers. The global production of waste glycerol by the refinery industry is rising year after year. The aim of the present study was to examine the effect of ethyl methane sulfonate (EMS) on the growth rates and intracellular lipid accumulation in heterotrophically-cultured microalgae, grown on waste glycerol as the carbon source. The strain E20, produced by incubating a reference strain in EMS for 20 min, was found to perform the best in terms of producing biomass (0.054 g/dm·h) and accumulating intracellular bio-oil (0.021 g/dm·h). The selected parameters proved to be optimal for E20 biomass growth at the following values: temperature 27.3 °C, glycerol level 249.0 g/dm, oxygen in the culture 26%, and yeast extract concentration 45.0 g/dm. In turn, the optimal values for lipid production in an E20 culture were: temperature 24.2 °C, glycerol level 223.0 g/dm, oxygen in the culture 10%, and yeast extract concentration 10.0 g/dm. As the process conditions are different for biomass growth and for intracellular lipid accumulation, it is recommended to use a two-step culture process, which resulted in a lipid synthesis rate of 0.41 g/dm·h.
Topics: Biofuels; Biomass; Docosahexaenoic Acids; Ethyl Methanesulfonate; Glycerol; Methane; Oxygen; Stramenopiles
PubMed: 35270800
DOI: 10.3390/ijerph19053108 -
Proceedings of the National Academy of... Sep 2019Dimethylsulfide (DMS), a gas produced by marine microbial food webs, promotes aerosol formation in pristine atmospheres, altering cloud radiative forcing and...
Dimethylsulfide (DMS), a gas produced by marine microbial food webs, promotes aerosol formation in pristine atmospheres, altering cloud radiative forcing and precipitation. Recent studies suggest that DMS controls aerosol formation in the summertime Arctic atmosphere and call for an assessment of pan-Arctic DMS emission (EDMS) in a context of dramatic ecosystem changes. Using a remote sensing algorithm, we show that summertime EDMS from ice-free waters increased at a mean rate of 13.3 ± 6.7 Gg S decade (∼33% decade) north of 70°N between 1998 and 2016. This trend, mostly explained by the reduction in sea-ice extent, is consistent with independent atmospheric measurements showing an increasing trend of methane sulfonic acid, a DMS oxidation product. Extrapolation to an ice-free Arctic summer could imply a 2.4-fold (±1.2) increase in EDMS compared to present emission. However, unexpected regime shifts in Arctic geo- and ecosystems could result in future EDMS departure from the predicted range. Superimposed on the positive trend, EDMS shows substantial interannual changes and nonmonotonic multiyear trends, reflecting the interplay between physical forcing, ice retreat patterns, and phytoplankton productivity. Our results provide key constraints to determine whether increasing marine sulfur emissions, and resulting aerosol-cloud interactions, will moderate or accelerate Arctic warming in the context of sea-ice retreat and increasing low-level cloud cover.
Topics: Aerosols; Arctic Regions; Atmosphere; Climate; Ecosystem; Ice Cover; Mesylates; Oceans and Seas; Phytoplankton; Seasons; Seawater; Sulfides
PubMed: 31501321
DOI: 10.1073/pnas.1904378116 -
MSphere Oct 2021Tannerella forsythia is a Gram-negative oral pathogen known to possess an O-glycosylation system responsible for targeting multiple proteins associated with virulence at...
Tannerella forsythia is a Gram-negative oral pathogen known to possess an O-glycosylation system responsible for targeting multiple proteins associated with virulence at the three-residue motif (D)(S/T)(A/I/L/V/M/T). Multiple proteins have been identified to be decorated with a decasaccharide glycan composed of a poorly defined core plus a partially characterized species-specific section. To date, glycosylation studies have focused mainly on the two S-layer glycoproteins, TfsA and TfsB, so the true extent of glycosylation within this species has not been fully explored. In the present study, we characterize the glycoproteome of by employing FAIMS-based glycopeptide enrichment of a cell membrane fraction. We demonstrate that at least 13 glycans are utilized within the glycoproteome, varying with respect to the presence of the three terminal sugars and the presence of fucose and digitoxose residues at the reducing end. To improve the localization of glycosylation events and enhance the detection of glycopeptides, we utilized trifluoromethanesulfonic acid treatment to allow the selective chemical cleavage of glycans. Reducing the chemical complexity of glycopeptides dramatically improved the number of glycopeptides identified and our ability to localize glycosylation sites by ETD fragmentation, leading to the identification of 312 putative glycosylation sites in 145 glycoproteins. Glycosylation site analysis revealed that glycosylation occurs on a much broader motif than initially reported, with glycosylation found at (D)(S/T)(A/I/L/V/M/T/S/C/G/F). The prevalence of this broader glycosylation motif in the genome suggests the existence of hundreds of potential O-glycoproteins in this organism. Tannerella forsythia is an oral pathogen associated with severe forms of periodontal disease characterized by destruction of the tooth's supporting tissues, including the bone. The bacterium releases a variety of proteins associated with virulence on the surface of outer membrane vesicles. There is evidence that these proteins are modified by glycosylation, and this modification is essential for virulence in producing disease. We have utilized novel techniques coupled with mass spectrometry to identify over 13 glycans and 312 putative glycosylation sites in 145 glycoproteins within . Glycosylation site analysis revealed that this modification occurs on a much broader motif than initially reported such that there is a high prevalence of potential glycoproteins in this organism that may help to explain its role in periodontal disease.
Topics: Bacterial Proteins; Glycoproteins; Glycosylation; Mass Spectrometry; Membrane Glycoproteins; Mesylates; Protein Transport; Proteome; Tannerella forsythia; Virulence
PubMed: 34523981
DOI: 10.1128/mSphere.00649-21 -
Journal of the American Chemical Society Jun 2020While phenols are frequent and convenient aryl sources in cross-coupling, typically as sulfonate esters, the direct cross-Ullmann coupling of two different sulfonate...
While phenols are frequent and convenient aryl sources in cross-coupling, typically as sulfonate esters, the direct cross-Ullmann coupling of two different sulfonate esters is unknown. We report here a general solution to this challenge catalyzed by a combination of Ni and Pd with Zn reductant and LiBr as an additive. The reaction has broad scope, as demonstrated in 33 examples (65% ± 11% average yield). Mechanistic studies show that Pd strongly prefers the aryl triflate, the Ni catalyst has a small preference for the aryl tosylate, aryl transfer between catalysts is mediated by Zn, and Pd improves yields by consuming arylzinc intermediates.
Topics: Catalysis; Mesylates; Molecular Structure; Nickel; Palladium; Sulfonic Acids; Tosyl Compounds; Zinc
PubMed: 32486635
DOI: 10.1021/jacs.0c04670 -
BMC Plant Biology Jul 2022Metals such as Zn or Cd are toxic to plant and humans when they are exposed in high quantities through contaminated soil or food. Noccaea caerulescens, an extraordinary...
BACKGROUND
Metals such as Zn or Cd are toxic to plant and humans when they are exposed in high quantities through contaminated soil or food. Noccaea caerulescens, an extraordinary Zn/Cd/Ni hyperaccumulating species, is used as a model plant for metal hyperaccumulation and phytoremediation studies. Current reverse genetic techniques to generate mutants based on transgenesis is cumbersome due to the low transformation efficiency of this species. We aimed to establish a mutant library for functional genomics by a non-transgenic approach, to identify mutants with an altered mineral profiling, and to screen for mutations in bZIP19, a regulator of Zn homeostasis in N. caerulescens.
RESULTS
To generate the N. caerulescens mutant library, 3000 and 5000 seeds from two sister plants of a single-seed recurrent inbred descendant of the southern French accession Saint-Félix-de-Pallières (SF) were mutagenized respectively by 0.3 or 0.4% ethyl methane sulfonate (EMS). Two subpopulations of 5000 and 7000 M2 plants were obtained after 0.3 or 0.4% EMS treatment. The 0.4% EMS treatment population had a higher mutant frequency and was used for TILLING. A High Resolution Melting curve analysis (HRM) mutation screening platform was optimized and successfully applied to detect mutations for NcbZIP19, encoding a transcription factor controlling Zn homeostasis. Of four identified point mutations in NcbZIP19, two caused non-synonymous substitutions, however, these two mutations did not alter the ionome profile compared to the wild type. Forward screening of the 0.4% EMS treatment population by mineral concentration analysis (ionomics) in leaf material of each M2 plant revealed putative mutants affected in the concentration of one or more of the 20 trace elements tested. Several of the low-Zn mutants identified in the ionomic screen did not give progeny, illustrating the importance of Zn for the species. The mutant frequency of the population was evaluated based on an average of 2.3 knockout mutants per tested monogenic locus.
CONCLUSIONS
The 0.4% EMS treatment population is effectively mutagenized suitable for forward mutant screens and TILLING. Difficulties in seed production in low Zn mutants, obtained by both forward and reverse genetic approach, hampered further analysis of the nature of the low Zn phenotypes.
Topics: Biodegradation, Environmental; Brassicaceae; Cadmium; Ethyl Methanesulfonate; Humans; Metals; Zinc
PubMed: 35869423
DOI: 10.1186/s12870-022-03739-x -
PloS One 2018[18F]FAC (2'-deoxy-2'-[18F]fluoro-β-D-arabinofuranosylcytosine, 1) is a versatile probe for imaging deoxycytidine kinase (dCK) expression levels in vivo. dCK is...
[18F]FAC (2'-deoxy-2'-[18F]fluoro-β-D-arabinofuranosylcytosine, 1) is a versatile probe for imaging deoxycytidine kinase (dCK) expression levels in vivo. dCK is responsible for phosphorylation of deoxycytidine (dC, 2) and other nucleoside analogs, plays a key role in immune activation and has demonstrated to be one of the key enzymes in activating nucleoside based drugs including gemcitabine. Reported synthesis of [18F]FAC is high yielding but is quite challenging requiring bromination using HBr and careful drying of excess HBr which is critical for successful synthesis. Here in we report a simplified trimethylsilyl trifluoromethanesulfonate (TMSOTf) assisted synthesis of [18F]FAC eliminating the need of bromination and drying. [18F]FAC (β-anomer) was synthesized with average isolated decay corrected yield of 10.59 + 4.2% (n = 6) with radiochemical purity of >98% and total synthesis time of 158 + 19 min.
Topics: Cytarabine; Deoxycytidine; Deoxycytidine Kinase; Fluorine Radioisotopes; Mesylates; Radiochemistry; Radiopharmaceuticals; Trimethylsilyl Compounds; Gemcitabine
PubMed: 29715301
DOI: 10.1371/journal.pone.0196784 -
Journal of Aerosol Medicine and... Dec 2022Oral tablets account for the majority of medications used to acutely treat migraine, but relief can be limited by their rates of dissolution and absorption. The nose is... (Review)
Review
Oral tablets account for the majority of medications used to acutely treat migraine, but relief can be limited by their rates of dissolution and absorption. The nose is an attractive alternative route of drug delivery since it provides patient convenience of at-home use, gastrointestinal (GI) avoidance, and rapid absorption of drugs into systemic circulation because of its large surface area. However, the site of drug deposition within the nasal cavity should be considered since it can influence drug absorption. Traditional nasal devices have been shown to target drug delivery to the lower nasal space where epithelium is not best-suited for drug absorption and where there is an increased likelihood of drug clearance due to nasal drip, swallowing, or mucociliary clearance, potentially resulting in variable absorption and suboptimal efficacy. Alternatively, the upper nasal space (UNS) offers a permeable, richly vascularized epithelium with a decreased likelihood of drug loss or clearance due to the anatomy of this area. Traditional nasal pumps deposit <5% of active drug into the UNS because of the nasal cavity's complex architecture. A new technology, Precision Olfactory Delivery (POD), is a handheld, manually actuated, propellant-powered, administration device that delivers drug specifically to the UNS. A dihydroergotamine (DHE) mesylate product, INP104, utilizes POD technology to deliver drug to the UNS for the acute treatment of migraine. Results from clinical studies of INP104 demonstrate a favorable pharmacokinetic profile, consistent and predictable dosing, rapid systemic levels known to be effective (similar to other DHE mesylate clinical programs), safety and tolerability on the upper nasal mucosa, and high patient acceptance. POD technology may have the potential to overcome the limitations of traditional nasal delivery systems, while utilizing the nasal delivery benefits of GI tract avoidance, rapid onset, patient convenience, and ease of use.
Topics: Humans; Dihydroergotamine; Administration, Intranasal; Administration, Inhalation; Migraine Disorders; Technology; Mesylates
PubMed: 36108289
DOI: 10.1089/jamp.2022.0005