Automated high-content imaging for cellular uptake, from the Schmuck cation to the latest cyclic oligochalcogenides

• Rémi Martinent,
• Javier López-Andarias,
• Dimitri Moreau,
• Yangyang Cheng,
• Naomi Sakai and
• Stefan Matile

Beilstein J. Org. Chem. 2020, 16, 2007–2016, doi:10.3762/bjoc.16.167

• for the thiol-mediated uptake, beginning with a dynamic covalent disulfide exchange with exofacial thiols, followed by either endocytosis or the direct crossing of membranes into cytosols through successive thiolate–disulfide exchange reactions or micellar pores (Figure 5b) [61]. Anionic glutamate was

Synthesis of monophosphorylated lipid A precursors using 2-naphthylmethyl ether as a protecting group

• Jundi Xue,
• Ziyi Han,
• Gen Li,
• Khalisha A. Emmanuel,
• Cynthia L. McManus,
• Qiang Sui,
• Dongmian Ge,
• Qi Gao and
• Li Cai

Beilstein J. Org. Chem. 2020, 16, 1955–1962, doi:10.3762/bjoc.16.162

• continued rise of problematic bacterial infections. Notably, the LPS pathogenicity is almost entirely due to lipid A because it leads to immunostimulatory effects when LPS dissociates from bacterial membranes within a host [5]. While these immunostimulatory effects can be beneficial in the setting of

Design, synthesis and application of carbazole macrocycles in anion sensors

• Alo Rüütel,
• Ville Yrjänä,
• Sandip A. Kadam,
• Indrek Saar,
• Mihkel Ilisson,
• Astrid Darnell,
• Kristjan Haav,
• Tõiv Haljasorg,
• Lauri Toom,
• Johan Bobacka and
• Ivo Leito

Beilstein J. Org. Chem. 2020, 16, 1901–1914, doi:10.3762/bjoc.16.157

• sensor development, the results obtained in this work emphasize the importance of evaluating the binding behavior of receptors in real sensor membranes. Keywords: anion sensors; carboxylates; ionophores; macrocycles; sensor prototype; Introduction In 2013, Otto S. Wolfbeis asked the supramolecular

• different types of materials such as glass, crystal, or polymer. pH electrodes with glass membranes are the most used ISEs and produce highly selective responses over a wide range of concentrations. Polymeric membranes have gained popularity due to their robustness, the ability to fine-tune their properties

• prototypes The sensor prototype preparations were done similarly to our previously published method for an acetate-selective solid-contact electrode [32]. Three macrocyclic receptors with different ring sizes were chosen as ionophores: MC005, MC009, and MC012. Ion-selective membranes (ISMs) were prepared

Cascade trifluoromethylthiolation and cyclization of N-[(3-aryl)propioloyl]indoles

• Ming-Xi Bi,
• Shuai Liu,
• Yangen Huang,
• Xiu-Hua Xu and
• Feng-Ling Qing

Beilstein J. Org. Chem. 2020, 16, 657–662, doi:10.3762/bjoc.16.62

• SCF3, 0.88 for CF3, and 0.61 for SMe) [1] that helps permeation across biological membranes. Furthermore, the strong electron-withdrawing properties of the SCF3 group (Hammett constants: σp = 0.50, σm = 0.40) [2] with respect to metabolic stability have attracted considerable interest in pharmaceutical

Light-controllable dithienylethene-modified cyclic peptides: photoswitching the in vivo toxicity in zebrafish embryos

• Sergii Afonin,
• Oleg Babii,
• Aline Reuter,
• Volker Middel,
• Masanari Takamiya,
• Uwe Strähle,
• Igor V. Komarov and
• Anne S. Ulrich

Beilstein J. Org. Chem. 2020, 16, 39–49, doi:10.3762/bjoc.16.6

• bacterial membranes, with considerable side-effects also on eukaryotic cell membranes [27][28]. Compared to the ring-closed (deactivated, OFF) photoform, the ring-open (active, ON) isomer of 2 indeed displayed a much stronger in vitro toxicity against several tumor cell lines [29][30]. Using the

Plasma membrane imaging with a fluorescent benzothiadiazole derivative

• Pedro H. P. R. Carvalho,
• Jose R. Correa,
• Karen L. R. Paiva,
• Daniel F. S. Machado,
• Jackson D. Scholten and
• Brenno A. D. Neto

Beilstein J. Org. Chem. 2019, 15, 2644–2654, doi:10.3762/bjoc.15.257

• for all tested models. Keywords: benzothiadiazole; bioprobe; cell imaging; fluorescence; mitochondria; molecular architecture; plasma membrane; Introduction The selective staining of plasma membranes is of paramount importance to study cellular processes and events associated with this dynamic

• cellular component. After more than one century of the idea considering cell plasma membranes as lipid bilayers [1], the importance to understand the functions, processes and events associated with plasma membranes is still vital. We are only beginning to understand many of the processes and functions

• related to this component responsible for the boundaries of the cells [2][3][4]. Various details have emerged due to the development of new sensitive molecular probes capable of staining organelles and cell components selectively, however, many open questions remain. Plasma membranes are the natural

Sugar-derived oxazolone pseudotetrapeptide as γ-turn inducer and anion-selective transporter

• Sachin S. Burade,
• Sushil V. Pawar,
• Tanmoy Saha,
• Navanath Kumbhar,
• Amol S. Kotmale,
• Manzoor Ahmad,
• Pinaki Talukdar and
• Dilip D. Dhavale

Beilstein J. Org. Chem. 2019, 15, 2419–2427, doi:10.3762/bjoc.15.234

• cation and anion transport across lipid bilayer membranes plays a crucial role in various biological processes [31][32]. Amongst these, the transport of anions is useful in regulating intracellular pH, membrane potential, cell volume, and fluid transport [33]. Any dysfunction in these processes led to

• [17][18], we investigated the ion transport activity of 1 and 2a across lipid bilayer membranes. In this study, the collapse of the pH gradient (pHout = 7.8 and pHin = 7.0), created across egg yolk ʟ-α-phosphatidylcholine (EYPC) vesicles with entrapped 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium

• interaction. However, the role of the neighboring amido groups cannot be ruled out. Moreover, the hydrophobic outer surface of the transporter helps the anion bound complex to permeate efficiently through the lipid bilayer membranes. Conclusion In conclusion, the intramolecular cyclization of linear di- and

Targeted photoswitchable imaging of intracellular glutathione by a photochromic glycosheet sensor

• Xianzhi Chai,
• Hai-Hao Han,
• Yi Zang,
• Jia Li,
• Xiao-Peng He,
• Junji Zhang and
• He Tian

Beilstein J. Org. Chem. 2019, 15, 2380–2389, doi:10.3762/bjoc.15.230

• recognition between β-D-galactoside and asialoglycoprotein receptor (ASGPr) on cell membranes. The dynamic fluorescence signals and excellent selectivity for detection and imaging of GSH ensure the precise determination of cell states, promoting its potential applications in future disease diagnosis and

• role of ASGPr on HepG2 cell membranes [36][37]. As shown in Figure S4 (Supporting Information File 1), the addition of PNA to the solution of Glyco-DTE resulted in a fluorescence enhancement with an obvious spectral blue-shift, while the addition of another lectin, conconavalin A (Con A), did not cause

• ]. Compared to the conventional sensor, which is vulnerable towards the inherent background signals from the intracellular environment, the photochromic probe provides a smart strategy of well-discrimination from physiological interferences. Apart from the over-expressed ASGPr receptors on cell membranes, the

Synthesis of a dihalogenated pyridinyl silicon rhodamine for mitochondrial imaging by a halogen dance rearrangement

• Jessica Matthias,
• Thines Kanagasundaram,
• Klaus Kopka and
• Carsten S. Kramer

Beilstein J. Org. Chem. 2019, 15, 2333–2343, doi:10.3762/bjoc.15.226

• membranes. Recently, a silicon rhodamine for selective mitochondrial staining was developed by conjugation of the SiR core with ten different amines varying in lipophilicity [46]. The authors showed that the optimal range of clogP values for mitochondrial targeting ranges from 5.50 to 6.33. As mentioned

Isolation and biosynthesis of an unsaturated fatty acid with unusual methylation pattern from a coral-associated bacterium Microbulbifer sp.

• Amit Raj Sharma,
• Enjuro Harunari,
• Tao Zhou,
• Agus Trianto and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2019, 15, 2327–2332, doi:10.3762/bjoc.15.225

• and methylation takes place at C3 to give a putative cationic intermediate. The following proton loss from C3 is probable to give directly 1 in a similar fashion to the glucosylceramide biosynthesis. Branched chain fatty acids are commonly present in cell membranes, and mono-methylation at the iso or

Isolation of fungi using the diffusion chamber device FIND technology

• Benjamin Libor,
• Henrik Harms,
• Stefan Kehraus,
• Ekaterina Egereva,
• Max Crüsemann and
• Gabriele M. König

Beilstein J. Org. Chem. 2019, 15, 2191–2203, doi:10.3762/bjoc.15.216

• enough for use in most natural environments. The central plate is a thin plastic board with 96 through holes that function as compartments, capable of holding inoculated agar plugs. Semipermeable membranes are attached to both sides of this plate, this way covering the through holes and preventing

• contamination by other microbes. These membranes, at the same time, permit diffusion of nutrients and growth factors from the environment through the feeding pores of the upper and lower plates. This way slow growing fungi or to date uncultured fungi can be isolated. To test the FIND technology, we used samples

• fungal part. As the agar solidified, the fungal spore or mycelium was trapped in the chamber and separated from other ones, e.g., competing organisms. Semipermeable membranes were attached to both sides of the central plate and the device was sealed with the upper and lower parts and fixed with screws

N-(1-Phenylethyl)aziridine-2-carboxylate esters in the synthesis of biologically relevant compounds

• Iwona E. Głowacka,
• Aleksandra Trocha,
• Andrzej E. Wróblewski and
• Dorota G. Piotrowska

Beilstein J. Org. Chem. 2019, 15, 1722–1757, doi:10.3762/bjoc.15.168

• (2S,3R)-95 in three standard steps. Ceramide and other sphingolipids are mainly localized in cell membranes and are involved in important cell processes. A series of constrained analogues of ceramide (2S,3R)-96 modified by converting the terminal aminohydroxy fragment into oxazolidin-2-one and

Molecular basis for the plasticity of aromatic prenyltransferases in hapalindole biosynthesis

• Takayoshi Awakawa and
• Ikuro Abe

Beilstein J. Org. Chem. 2019, 15, 1545–1551, doi:10.3762/bjoc.15.157

• bioactive compounds, because the prenylated compounds exhibit better bioactivities due to their improved interactions with biological membranes [3]. The aromatic PTase superfamily involved in the secondary metabolism consists of the ABBA (α-β-β-α barrel)-type [4][5], the dimethylallyltryptophan synthase

Complexation of a guanidinium-modified calixarene with diverse dyes and investigation of the corresponding photophysical response

• Yu-Ying Wang,
• Yong Kong,
• Zhe Zheng,
• Wen-Chao Geng,
• Zi-Yi Zhao,
• Hongwei Sun and
• Dong-Sheng Guo

Beilstein J. Org. Chem. 2019, 15, 1394–1406, doi:10.3762/bjoc.15.139

• non-fluorescent in aqueous solution, but become highly fluorescent in non-polar solvents or when they are bound to proteins and membranes [42][43]. This enhancement is commonly understood in terms of the relocation of the guest into the more hydrophobic environment. The decreased rate constant of

Host–guest interactions between p-sulfonatocalix[4]arene and p-sulfonatothiacalix[4]arene and group IA, IIA and f-block metal cations: a DFT/SMD study

• Valya K. Nikolova,
• Cristina V. Kirkova,
• Silvia E. Angelova and
• Todor M. Dudev

Beilstein J. Org. Chem. 2019, 15, 1321–1330, doi:10.3762/bjoc.15.131

• , biopharmaceutical, biological, biomimetic (enzyme mimics, transport across membranes, ion channels, etc.) and biomedical (in cancer chemotherapy) applications, reviewed by Atwood et al. [15], Perret et al. [16], Da Silva et al. [17], Nimse et al. [18], Guo et al. [19], Agrawal et al. [20], Yousaf et al. [21]. The

Fabrication, characterization and adsorption properties of cucurbit[7]uril-functionalized polycaprolactone electrospun nanofibrous membranes

• Changzhong Chen,
• Fengbo Liu,
• Xiongzhi Zhang,
• Zhiyong Zhao and
• Simin Liu

Beilstein J. Org. Chem. 2019, 15, 992–999, doi:10.3762/bjoc.15.97

• present in the PCL fiber matrix in an uncomplexed state. The static adsorption behavior of the PCL/CB[7] nanofibers towards methylene blue (MB) was also preliminary investigated. The results indicate that the adsorption of MB onto the nanofibrous membranes fits the second-order kinetic model and Langmuir

• series of CD-functionalized electrospun nanofibers in the forms of CD-pseudopolyrotaxane [11][12], CDs/polymer [13][14][15], CD-ICs/polymer [16][17], and polymer-free CDs [5][18] or CD-ICs [19] have been fabricated. In addition, calix[8]arene (C[8])/polyacrylonitrile (PAN) composite nanofiber membranes

• the PCL/CB[7] (100:50) nanofibers when compared with the neat PCL nanofibers (Figure 1a and 1b). With the increase of CB[7] loading, a few shuttle-shaped beads in the nanofibrous membranes appeared, and the surface of the composite nanofibers became more and more rough or lumpy (Figure 1c–e

Design and synthesis of multivalent α-1,2-trimannose-linked bioerodible microparticles for applications in immune response studies of Leishmania major infection

• Chelsea L. Rintelmann,
• Tara Grinnage-Pulley,
• Kathleen Ross,
• Daniel E. K. Kabotso,
• Angela Toepp,
• Anne Cowell,
• Christine Petersen,
• Balaji Narasimhan and
• Nicola Pohl

Beilstein J. Org. Chem. 2019, 15, 623–632, doi:10.3762/bjoc.15.58

• ]. Cutaneous, the most common form, causes severe nodular and ulcerative skin lesions, while mucocutaneous destroys mucus membranes, and the most deadly form, visceral leishmaniasis, often results in organ failure [6]. L. major, the parasite used in our in vivo model, causes the cutaneous disease. In each

Cyclopropene derivatives of aminosugars for metabolic glycoengineering

• Jessica Hassenrück and
• Valentin Wittmann

Beilstein J. Org. Chem. 2019, 15, 584–601, doi:10.3762/bjoc.15.54

Olefin metathesis in multiblock copolymer synthesis

• Maria L. Gringolts,
• Yulia I. Denisova,
• Eugene Sh. Finkelshtein and
• Yaroslav V. Kudryavtsev

Beilstein J. Org. Chem. 2019, 15, 218–235, doi:10.3762/bjoc.15.21

• attract ongoing attention from both experimentalists and theoreticians due to their intrinsic tendency to self-assemble into diverse microstructures [8][9][10][11]. Technological applications of block copolymers cover lithography [12], photovoltaics [13], membranes [14] and many other areas [15]. Most of

Synthesis and biological activity of methylated derivatives of the Pseudomonas metabolites HHQ, HQNO and PQS

• Sven Thierbach,
• Max Wienhold,
• Susanne Fetzner and
• Ulrich Hennecke

Beilstein J. Org. Chem. 2019, 15, 187–193, doi:10.3762/bjoc.15.18

• OD600 nm of 0.2. Each well contained 1 mL of cell suspension including 100 µM of the AQ derivatives or an equal amount of DMSO. The plates were sealed with optically clear and gas permeable membranes, incubated at 37 °C while shaking and the OD600 nm was measured at certain time points. Experiments were

Olefin metathesis catalysts embedded in β-barrel proteins: creating artificial metalloproteins for olefin metathesis

• Daniel F. Sauer,
• Johannes Schiffels,
• Takashi Hayashi,
• Ulrich Schwaneberg and
• Jun Okuda

Beilstein J. Org. Chem. 2018, 14, 2861–2871, doi:10.3762/bjoc.14.265

• NO transport, storage and sensing as well as heme metabolism [36]) usually constitute eight to ten antiparallel β-strands and tightly packed hydrophobic or hydrophilic barrel interiors [37]. Membrane-bound β-barrels are confined to mitochondrial and chloroplast membranes and the outer membranes of

• point are relatively small and soluble proteins. As introduced vide supra, membrane-spanning porins and transporters of the all-β-barrel type, which are found in cellular outer membranes, constitute substantially larger “barrel” interiors and were thus utilized as scaffolds to house bulky GH-type

Pathoblockers or antivirulence drugs as a new option for the treatment of bacterial infections

• Matthew B. Calvert,
• Varsha R. Jumde and
• Alexander Titz

Beilstein J. Org. Chem. 2018, 14, 2607–2617, doi:10.3762/bjoc.14.239

• systems exist in bacteria [65] and the Gram-negative specific type III secretion system (TTSS) is a focus of current research. TTSS is a major virulence determinant in a number of pathogens, including P. aeruginosa. In TTSS, toxins are secreted from the bacterial cytosol across the bacterial membranes and

Natural and redesigned wasp venom peptides with selective antitumoral activity

• Marcelo D. T. Torres,
• Gislaine P. Andrade,
• Roseli H. Sato,
• Cibele N. Pedron,
• Tania M. Manieri,
• Giselle Cerchiaro,
• Anderson O. Ribeiro,
• Cesar de la Fuente-Nunez and
• Vani X. Oliveira Jr.

Beilstein J. Org. Chem. 2018, 14, 1693–1703, doi:10.3762/bjoc.14.144

• membranes increased significantly when treated with lead peptides compared to controls. Biophysical features such as helicity, hydrophobicity, and net positive charge were identified to play an important role in the anticancer activity of the peptides. Indeed, abrupt changes in peptide hydrophobicity and

• key for their anticancer activity, as they enable membrane binding [20]. Their anticancer activity typically occurs at micromolar concentrations [21] and is not usually accompanied by hemolytic activity probably because there are structural differences between the membranes of red blood cells and

• cancer cells, which are zwitterionic and negatively charged, respectively. Structure–activity relationship studies have identified amphiphilicity and polar angle as the most important physicochemical properties required for ACPs to invade cancer cells or disturb their membranes [22][23]. In 2007, Konno

Drug targeting to decrease cardiotoxicity – determination of the cytotoxic effect of GnRH-based conjugates containing doxorubicin, daunorubicin and methotrexate on human cardiomyocytes and endothelial cells

• Livia Polgár,
• Eszter Lajkó,
• Pál Soós,
• Orsolya Láng,
• Marilena Manea,
• Béla Merkely,
• Gábor Mező and
• László Kőhidai

Beilstein J. Org. Chem. 2018, 14, 1583–1594, doi:10.3762/bjoc.14.136

• environment, due to the electric insulator character of intact surface membranes composed of the phospholipid bilayer. Application of cytotoxic compounds results in disturbed electrophysical integrity (decreasing value of impedance) of surface membranes as a signal of cell death. While cell physiological

Spectroelectrochemical studies on the effect of cations in the alkaline glycerol oxidation reaction over carbon nanotube-supported Pd nanoparticles

• Dennis Hiltrop,
• Steffen Cychy,
• Karina Elumeeva,
• Wolfgang Schuhmann and
• Martin Muhler

Beilstein J. Org. Chem. 2018, 14, 1428–1435, doi:10.3762/bjoc.14.120

• utilization in fuel cells (FCs) converting chemical into electrical energy [5]. In alkaline FCs (AFCs) and proton exchange membrane FCs (PEMFCs), H2 and O2 are converted to H2O, heat and electricity. Since the development of anion exchange membranes the research interest in AFCs has increased again, because