scholarly journals Not Just Transporters: Alternative Functions of ABC Transporters in Bacillus subtilis and Listeria monocytogenes

2021 ◽  
Vol 9 (1) ◽  
pp. 163
Author(s):  
Jeanine Rismondo ◽  
Lisa Maria Schulz
Keyword(s):  
Bacillus Subtilis ◽  
Listeria Monocytogenes ◽  
Abc Transporters ◽  
Organic Molecules ◽  
Atp Hydrolysis ◽  
The Past ◽  
Wide Range ◽  
Regulatory Functions ◽  
Complex Organic ◽  
Detoxification Mechanisms

ATP-binding cassette (ABC) transporters are usually involved in the translocation of their cognate substrates, which is driven by ATP hydrolysis. Typically, these transporters are required for the import or export of a wide range of substrates such as sugars, ions and complex organic molecules. ABC exporters can also be involved in the export of toxic compounds such as antibiotics. However, recent studies revealed alternative detoxification mechanisms of ABC transporters. For instance, the ABC transporter BceAB of Bacillus subtilis seems to confer resistance to bacitracin via target protection. In addition, several transporters with functions other than substrate export or import have been identified in the past. Here, we provide an overview of recent findings on ABC transporters of the Gram-positive organisms B. subtilis and Listeria monocytogenes with transport or regulatory functions affecting antibiotic resistance, cell wall biosynthesis, cell division and sporulation.

Bio-habitability and life on planets of M-G-type stars

2018 ◽  
Vol 14 (S345) ◽  
pp. 189-193
Author(s):  
Amri Wandel
Keyword(s):  
Liquid Water ◽  
Organic Molecules ◽  
Planetary Surface ◽  
Habitable Zone ◽  
Wide Range ◽  
Complex Organic

AbstractThe recent detection of Earth-sized planets in the habitable zone of Proxima Centauri, Trappist-1, and many other nearby M-type stars (which consist some 75% of the stars) has led to speculations, whether liquid water and life actually exist on these planets. Defining the bio-habitable zone, where liquid water and complex organic molecules can survive on at least part of the planetary surface, we suggest that planets orbiting M-type stars may have life-supporting conditions for a wide range of atmospheric properties (Wandel2018). We extend this analysis to synchronously orbiting planets of K- and G-type stars and discuss the implications for the evolution and sustaining of life on planets of M- to G-type stars, in analogy to Earth.

Alkylation Reactions with Alkylsulfonium Salts

Synthesis ◽  
2021 ◽  
Author(s):  
Ze-Yu Tian ◽  
Yu Ma ◽  
Cheng-Pan Zhang
Keyword(s):  
Organic Molecules ◽  
High Efficiency ◽  
Building Blocks ◽  
Organometallic Reagents ◽  
The Past ◽  
Wide Range ◽  
Catalyzed Reactions ◽  
Metal Catalyzed ◽  
Alkylation Reactions

Application of alkylsulfonium salts as alkyl transfer reagents in organic synthesis has reemerged over the past years. Numerous heteroatom- and carbon-centered nucleophiles, alkenes, arenes, alkynes, organometallic reagents, and others were readily alkylated by alkylsulfonium salts under mild conditions. The reactions feature convenience, high efficiency, readily accessible and structurally diversified alkylation reagents, good functional group tolerance, and a wide range of substrate types, allowing for facile synthesis of various useful organic molecules from the commercially available building blocks. This review summarizes the alkylation reactions using either isolated or in situ formed alkylsulfonium salts via nucleophilic substitution, transition-metal-catalyzed reactions, and photoredox processes.

scholarly journals Organic chemistry in circumstellar envelopes: Setting the stage for prebiotic synthesis

2008 ◽  
Vol 4 (S251) ◽  
pp. 147-156 ◽  
Author(s):  
Lucy M. Ziurys
Keyword(s):  
Organic Molecules ◽  
Prebiotic Synthesis ◽  
Asymptotic Giant Branch ◽  
Interstellar Space ◽  
Circumstellar Envelope ◽  
Circumstellar Envelopes ◽  
Wide Range ◽  
Circumstellar Gas ◽  
Circumstellar Shells ◽  
Complex Organic

AbstractOne of the few carbon-rich environments found in interstellar space is the ejecta of asymptotic giant branch (AGB) stars. Such material, which forms a circumstellar envelope, becomes enriched in carbon due to “dredge-up” phenomena associated with nucleosynthesis. A unique organic synthesis flourishes in the gas phase in these envelopes, and radio and millimeter observations have identified a wide range of C-bearing compounds, including long acetylenic chains such as HC5N, HC7N, C4H, C6H, C8H, C6H−, C8H−, and C3O. Oxygen-rich envelopes also have a non-negligible carbon chemistry, fostering species such as HCN and HCO+. Phosphorus chemistry appears to be active as well in circumstellar shells, as evidenced by the recent detections of HCP, CCP, and PO. Radio observations also indicate that some fraction of the circumstellar molecular material survives into the planetary nebula stage, and then becomes incorporated into diffuse, and eventually, dense clouds. The complex organic molecules found in dense clouds such as Sgr B2(N) may be the products of “seed” material that can be traced back to the carbon-enriched circumstellar gas.

scholarly journals The Detection of a Hot Molecular Core in the Extreme Outer Galaxy

2021 ◽  
Vol 922 (2) ◽  
pp. 206
Author(s):  
Takashi Shimonishi ◽  
Natsuko Izumi ◽  
Kenji Furuya ◽  
Chikako Yasui
Keyword(s):  
Organic Molecules ◽  
Large Magellanic Cloud ◽  
Galactocentric Distance ◽  
Star Forming ◽  
The Past ◽  
Molecular Core ◽  
Low Metallicity ◽  
Molecular Complexity ◽  
Molecular Abundances ◽  
Complex Organic

Abstract Interstellar chemistry in low-metallicity environments is crucial to understand chemical processes in the past metal-poor universe. Recent studies of interstellar molecules in nearby low-metallicity galaxies have suggested that metallicity has a significant effect on the chemistry of star-forming cores. Here we report the first detection of a hot molecular core in the extreme outer Galaxy, which is an excellent laboratory to study star formation and the interstellar medium in a Galactic low-metallicity environment. The target star-forming region, WB 89–789, is located at a galactocentric distance of 19 kpc. Our Atacama Large Millimeter/submillimeter Array observations in 241–246, 256–261, 337–341, and 349–353 GHz have detected a variety of carbon-, oxygen-, nitrogen-, sulfur-, and silicon-bearing species, including complex organic molecules (COMs) containing up to nine atoms, toward a warm (>100 K) and compact (<0.03 pc) region associated with a protostar (∼8 × 103 L ☉). Deuterated species such as HDO, HDCO, D2CO, and CH2DOH are also detected. A comparison of fractional abundances of COMs relative to CH3OH between the outer Galactic hot core and an inner Galactic counterpart shows a remarkable similarity. On the other hand, the molecular abundances in the present source do not resemble those of low-metallicity hot cores in the Large Magellanic Cloud. The results suggest that great molecular complexity exists even in the primordial environment of the extreme outer Galaxy. The detection of another embedded protostar associated with high-velocity SiO outflows is also reported.

Bathocuproine-Enabled Nickel-Catalyzed Selective Ullmann Cross-Coupling of Two sp2-Hybridized Organohalides

Synlett ◽  
2021 ◽  
Vol 32 (16) ◽  
pp. 1657-1661
Author(s):  
Yuqiang Li ◽  
Guoyin Yin
Keyword(s):  
Functional Groups ◽  
Organic Molecules ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Reaction Conditions ◽  
Cross Coupling Reactions ◽  
Wide Range ◽  
Complex Organic

AbstractCross-coupling reactions are essential for the synthesis of complex organic molecules. Here, we report a nickel-catalyzed Ullmann cross-coupling of two sp2-hybridized organohalides, featuring high cross-selectivity when the two coupling partners are used in a 1:1 ratio. The high chemoselectivity is governed by the bathocuproine ligand. Moreover, the mild reductive reaction conditions allow that a wide range of functional groups are compatible in this Ullmann cross-coupling.

Optical Properties of HVEM Accelerators

1975 ◽  
Vol 33 ◽  
pp. 180-181
Author(s):  
A. Strojnik ◽  
J.W. Scholl ◽  
V. Bevc
Keyword(s):  
Optical Properties ◽  
Electron Accelerator ◽  
Systematic Investigation ◽  
Electron Source ◽  
High Brightness ◽  
The Past ◽  
Wide Range ◽  
Optical Behavior

The electron accelerator, as inserted between the electron source (injector) and the imaging column of the HVEM, is usually a strong lens and should be optimized in order to ensure high brightness over a wide range of accelerating voltages and illuminating conditions. This is especially true in the case of the STEM where the brightness directly determines the highest resolution attainable. In the past, the optical behavior of accelerators was usually determined for a particular configuration. During the development of the accelerator for the Arizona 1 MEV STEM, systematic investigation was made of the major optical properties for a variety of electrode configurations, number of stages N, accelerating voltages, 1 and 10 MEV, and a range of injection voltages ϕ0 = 1, 3, 10, 30, 100, 300 kV).

Pursuit of the Abscopal Effect

2020 ◽  
Vol 04 (04) ◽  
pp. 369-372
Author(s):  
Paul B. Romesser ◽  
Christopher H. Crane
Keyword(s):  
Tumor Immunology ◽  
Antitumor Immunity ◽  
Clinical Success ◽  
Immune Recognition ◽  
Immune Modulators ◽  
Cancer Subtypes ◽  
The Past ◽  
Tumor Irradiation ◽  
Wide Range ◽  
Tumor Recognition

AbstractEvasion of immune recognition is a hallmark of cancer that facilitates tumorigenesis, maintenance, and progression. Systemic immune activation can incite tumor recognition and stimulate potent antitumor responses. While the concept of antitumor immunity is not new, there is renewed interest in tumor immunology given the clinical success of immune modulators in a wide range of cancer subtypes over the past decade. One particularly interesting, yet exceedingly rare phenomenon, is the abscopal response, characterized by a potent systemic antitumor response following localized tumor irradiation presumably attributed to reactivation of antitumor immunity.

The Many Pasts of Detective Fiction

2020 ◽  
Vol 1 (2) ◽  
pp. 157-172
Author(s):  
Thomas Leitch
Keyword(s):  
Detective Fiction ◽  
Golden Age ◽  
Public History ◽  
Detective Novel ◽  
Sherlock Holmes ◽  
Detective Story ◽  
The Past ◽  
Wide Range ◽  
Detective Novels ◽  
The Many

Building on Tzvetan Todorov's observation that the detective novel ‘contains not one but two stories: the story of the crime and the story of the investigation’, this essay argues that detective novels display a remarkably wide range of attitudes toward the several pasts they represent: the pasts of the crime, the community, the criminal, the detective, and public history. It traces a series of defining shifts in these attitudes through the evolution of five distinct subgenres of detective fiction: exploits of a Great Detective like Sherlock Holmes, Golden Age whodunits that pose as intellectual puzzles to be solved, hardboiled stories that invoke a distant past that the present both breaks with and echoes, police procedurals that unfold in an indefinitely extended present, and historical mysteries that nostalgically fetishize the past. It concludes with a brief consideration of genre readers’ own ambivalent phenomenological investment in the past, present, and future each detective story projects.

Nine Centuries of Man

2017 ◽  
Keyword(s):  
Twentieth Century ◽  
Diverse Range ◽  
Gender Expectations ◽  
Court Records ◽  
The Past ◽  
Wide Range ◽  
Police Reports ◽  
Late Twentieth ◽  
Scottish History ◽  
Late Twentieth Century

What did it mean to be a man in Scotland over the past nine centuries? Scotland, with its stereotypes of the kilted warrior and the industrial ‘hard man’, has long been characterised in masculine terms, but there has been little historical exploration of masculinity in a wider context. This interdisciplinary collection examines a diverse range of the multiple and changing forms of masculinities from the late eleventh to the late twentieth century, exploring the ways in which Scottish society through the ages defined expectations for men and their behaviour. How men reacted to those expectations is examined through sources such as documentary materials, medieval seals, romances, poetry, begging letters, police reports and court records, charity records, oral histories and personal correspondence. Focusing upon the wide range of activities and roles undertaken by men – work, fatherhood and play, violence and war, sex and commerce – the book also illustrates the range of masculinities that affected or were internalised by men. Together, the chapters illustrate some of the ways Scotland’s gender expectations have changed over the centuries and how, more generally, masculinities have informed the path of Scottish history

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