Nocarimidazoles C and D, antimicrobial alkanoylimidazoles from a coral-derived actinomycete Kocuria sp.: application of ¹J_C,H coupling constants for the unequivocal determination of substituted imidazoles and stereochemical diversity of anteisoalkyl chains in microbial metabolites

• Md. Rokon Ul Karim,
• Enjuro Harunari,
• Amit Raj Sharma,
• Naoya Oku,
• Kazuaki Akasaka,
• Daisuke Urabe,
• Mada Triandala Sibero and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 2719–2727, doi:10.3762/bjoc.16.222

• the same as those for 1 (Table 1). The antimicrobial activity of 1–4 was tested against Gram-positive bacteria Kocuria rhizophila and Staphylococcus aureus, Gram-negative bacteria Escherichia coli and Rhizobium radiobacter, a yeast Candida albicans, and two fungi Glomerella cingulata and Trichophyton

• rubrum (Table 2). All compounds exhibited moderate activity against Gram-positive bacteria with MICs of 6.25–12.5 μg/mL but were inactive against Gram-negative bacteria. The compounds 1–4 were also active against the yeast and fungi, with MIC values ranging from 6.25–25 μg/mL. In addition, the compounds

4-Hydroxy-3-methyl-2(1H)-quinolone, originally discovered from a Brassicaceae plant, produced by a soil bacterium of the genus Burkholderia sp.: determination of a preferred tautomer and antioxidant activity

• Dandan Li,
• Naoya Oku,
• Yukiko Shinozaki,
• Yoichi Kurokawa and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 1489–1494, doi:10.3762/bjoc.16.124

• rutaceous plants [9]. Examples from microbes include chymase inhibitors SF2809-I to VI from an actinomycete of the genus Dactylosporangium [10], a quorum sensing signaling molecule 2,4-dihydroxyquinoline (DHQ, 4) from Gram-negative bacteria Pseudomonas aeruginosa and Burkholderia thailandensis, [7], and 4-O

• aureus FDA209P JC-1 (Gram-positive bacterium), Rhizobium radiobacter NBRC14554, Ralstonia solanacearum SUPP1541, Tenacibaculum maritimum NBRC16015 (Gram-negative bacteria), Candida albicans NBRC0197, and Saccharomyces cerevisiae S100 (yeasts). Oxidative burst, which is a transient production of massive

Fabclavine diversity in Xenorhabdus bacteria

• Sebastian L. Wenski,
• Harun Cimen,
• Natalie Berghaus,
• Sebastian W. Fuchs,
• Selcuk Hazir and
• Helge B. Bode

Beilstein J. Org. Chem. 2020, 16, 956–965, doi:10.3762/bjoc.16.84

• against the tested Gram-positive and Gram-negative bacteria in the other strains analyzed (Table 3). Whether this bioactivity is due to individual members of the fabclavines or whether all of them have a comparable activity must be studied in the future after the isolation of the individual derivatives

• . Nevertheless, synergistic effects with other compound classes, enhancing the overall inhibitory activity, cannot be excluded. As an example, X. indica and X. cabanillasii showed an additional bioactivity against Gram-negative bacteria even without fabclavine production (Table 3). This bioactivity might be

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

• Gram-positive bacteria, Gram-negative bacteria, HeLa cells, and human erythrocytes) and were able to rationalize the specific impact of our modifications onto cell selectivity indices. Though all compounds demonstrated distinctly different cell toxicities in the ring-open and the ring-closed photoforms

Synthesis of C-glycosyl phosphonate derivatives of 4-amino-4-deoxy-α-ʟ-arabinose

• Lukáš Kerner and
• Paul Kosma

Beilstein J. Org. Chem. 2020, 16, 9–14, doi:10.3762/bjoc.16.2

• mechanisms of pathogenic Gram-negative bacteria against antibiotics, such as polymyxin B and colistin [3]. The main effect of Ara4N incorporation into the lipid A part – and, less frequently, into the inner core region of LPS [4] – is thought to originate from blocking the electrostatic interaction of

Skeletocutins M–Q: biologically active compounds from the fruiting bodies of the basidiomycete Skeletocutis sp. collected in Africa

• Tian Cheng,
• Clara Chepkirui,
• Cony Decock,
• Josphat C. Matasyoh and
• Marc Stadler

Beilstein J. Org. Chem. 2019, 15, 2782–2789, doi:10.3762/bjoc.15.270

• determined in serial dilution assays using several microorganisms, as described previously [8][9]. Herein, Gram-positive bacteria used were B. subtilis DSM10, MRSA DSM11822, S. aureus DSM346, M. luteus DSM20030, and Mycobacterium smegmatis (M. smegmatis) ATCC700084, Gram-negative bacteria were Escherichia

Chemical synthesis of the pentasaccharide repeating unit of the O-specific polysaccharide from Escherichia coli O132 in the form of its 2-aminoethyl glycoside

• Debasish Pal and
• Balaram Mukhopadhyay

Beilstein J. Org. Chem. 2019, 15, 2563–2568, doi:10.3762/bjoc.15.249

• expensive to get reasonable quantities of material with adequate purity. Therefore, the chemical syntheses of these complex structures become the only option to afford the material for detailed biological studies leading to the exploration of the vaccine potential. Escherichia coli is a Gram-negative

• bacteria present in the guts of human and other warm-blooded animals. It is usually harmless and beneficial to the host’s body, however, there are other variants of E. coli having virulence factors and causing diseases like diarrhea, urinary tract infection, septicaemia etc. E. coli O132 is reported to be

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

• associated with a gorgonian coral Junceella juncea [6], but there is no report on the compounds from stony coral-associated bacteria except our recently published work [7]. Microbulbifer is a genus of Gram-negative bacteria belonging to the class Gammaproteobacteria [8]. Members of this genus are frequently

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

• Escherichia coli were used as representatives for Gram-positive and Gram-negative bacteria. Microbotryum violaceum (Basidiomycete), Eurotium rubrum (Ascomycete), and Mycotypha microspora (Zygomycete) were used as fungal test organisms. Raw extracts were dissolved in MeOH to give a concentration of 1 mg/mL per

New terpenoids from the fermentation broth of the edible mushroom Cyclocybe aegerita

• Frank Surup,
• Florian Hennicke,
• Nadine Sella,
• Maria Stroot,
• Steffen Bernecker,
• Sebastian Pfütze,
• Marc Stadler and
• Martin Rühl

Beilstein J. Org. Chem. 2019, 15, 1000–1007, doi:10.3762/bjoc.15.98

• /mL, for KB3.1 = 7 µg/mL), but was inactive against all test organisms in our standard test panel, comprising selected Gram-positive and Gram-negative bacteria as well as fungi [8]. Compound 4 was inactive in all assays of our test panel, and 3 could not be tested due to the insufficient amount

Towards the preparation of synthetic outer membrane vesicle models with micromolar affinity to wheat germ agglutinin using a dialkyl thioglycoside

• Dimitri Fayolle,
• Nathalie Berthet,
• Bastien Doumeche,
• Olivier Renaudet,
• Peter Strazewski and
• Michele Fiore

Beilstein J. Org. Chem. 2019, 15, 937–946, doi:10.3762/bjoc.15.90

• membrane of Gram-negative bacteria, are considered today as attractive candidates for vaccine delivery. However, they have some disadvantages, they are not easy to produce and are difficult to characterize [2][3]. Moreover, toxic lipopolysaccharides (LPS) present in the outer membrane of most of Gram

• -negative bacteria prevent the medical use of OMV from natural sources [4]. Licensed vaccines based on crude OMV are currently available to contribute to the prevention and to control at least twenty-five infections including pulmonary ones [5]. Developing synthetic vaccines against cancer [6][7] or Gram

• ] or using natural glycolipids from Gram-negative bacteria such as lipid A [4]. This work represents the first step towards the formulation of an heterogeneous, stable systems (under biological conditions) that can be used for several biological purposes including synthetic vaccines, supramolecular

Lectins of Mycobacterium tuberculosis – rarely studied proteins

• Katharina Kolbe,
• Sri Kumar Veleti,
• Norbert Reiling and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2019, 15, 1–15, doi:10.3762/bjoc.15.1

• Abstract The importance of bacterial lectins for adhesion, pathogenicity, and biofilm formation is well established for many Gram-positive and Gram-negative bacteria. However, there is very little information available about lectins of the tuberculosis-causing bacterium, Mycobacterium tuberculosis (Mtb

• ], protozoa [57], and fungi [58], and totally absent in mammals. D-Arabinofuranose can only be found in prokaryotes, for example in Gram-negative bacteria where it is a cytoplasmic intermediate in the biosynthesis of 3-deoxy-D-manno-octulosonic acid (KDO), an essential carbohydrate of the cell wall

• (T4P) are surface-exposed fibers that mediate many functions in both Gram-positive and Gram-negative bacteria, including motility, adhesion to host cells, biofilm formation, DNA uptake, and protein secretion [120][121][122][123][124][125][126][127][128]. Mtb expresses T4P that appear by electron

N-Acylated amino acid methyl esters from marine Roseobacter group bacteria

• Hilke Bruns,
• Lisa Ziesche,
• Nargis Khakin Taniwal,
• Laura Wolter,
• Thorsten Brinkhoff,
• Jennifer Herrmann,
• Rolf Müller and
• Stefan Schulz

Beilstein J. Org. Chem. 2018, 14, 2964–2973, doi:10.3762/bjoc.14.276

• Roseobacter group (Rhodobacteraceae) are important members of many marine ecosystems. Similar to other Gram-negative bacteria many roseobacters produce N-acylhomoserine lactones (AHLs) for communication by quorum sensing systems. AHLs regulate different traits like cell differentiation or antibiotic

Protein–protein interactions in bacteria: a promising and challenging avenue towards the discovery of new antibiotics

• Laura Carro

Beilstein J. Org. Chem. 2018, 14, 2881–2896, doi:10.3762/bjoc.14.267

• selected NSAIDs was determined on four clinically relevant species, two Gram-negative bacteria (E. coli and A. baylyi) and two Gram-positive (S. aureus and B. subtilis). In opposition to Yin’s studies, the latter species showed higher susceptibility than the Gram-negative bacteria with minimal inhibitory

• polymerase III, and thus represent promising leads in the search for PPI inhibitors in bacteria. Filamenting temperature-sensitive protein Z (FtsZ) FtsZ is a prokaryotic tubulin-like protein which plays a crucial role in cell division in both Gram-positive and Gram-negative bacteria [83]. This protein

• between FtsZ and ZipA is essential for cell division in E. coli and other Gram-negative bacteria, and therefore, it has been suggested that disruption of the ZipA/FtsZ interaction can be exploited to develop potential antibacterial molecules [83][86]. The development of a small-molecule antibiotic that

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

• Gram-negative bacteria [38]. They constitute up to 24 strands, require sophisticated assembly machineries for membrane integration [39] and are usually “plugged” by hydrophilic loops and helices that either ensure the binding of small molecules, or their (energy-dependent) transport across the outer

Non-native autoinducer analogs capable of modulating the SdiA quorum sensing receptor in Salmonella enterica serovar Typhimurium

• Matthew J. Styles and
• Helen E. Blackwell

Beilstein J. Org. Chem. 2018, 14, 2651–2664, doi:10.3762/bjoc.14.243

• , host colonization, and biofilm formation at high population densities. This cell–cell signaling process is regulated by N-acyl L-homoserine lactone (AHL) signals, or autoinducers, and LuxR-type receptors in Gram-negative bacteria. SdiA is an orphan LuxR-type receptor found in Escherichia, Salmonella

• to coordinate group beneficial behaviors such as virulence factor production, host colonization, and biofilm formation at high population densities [12]. Gram-negative bacteria typically use N-acyl L-homoserine lactone (AHL) signals for QS, which are produced by LuxI-type synthases and sensed by

The design and synthesis of an antibacterial phenothiazine–siderophore conjugate

• Abed Tarapdar,
• James K. S. Norris,
• Oliver Sampson,
• Galina Mukamolova and
• James T. Hodgkinson

Beilstein J. Org. Chem. 2018, 14, 2646–2650, doi:10.3762/bjoc.14.242

• achieved with beta-lactam-based siderophore conjugates targeting membrane associated penicillin binding proteins (PBPs) [7]. Cefiderocol (S-649266) is a beta-lactam–siderophore conjugate currently in phase III clinical trials which demonstrates enhanced potency against Gram-negative bacteria including

• azotochelin. Catechol-based siderophores can act as xenosiderophores and be recognised for uptake by Gram-negative bacteria and mycobacteria [14][15]. Most commonly benzyl protecting groups are used in the synthesis of catechol siderophores and cleaved in the final step by palladium catalysed hydrogenation

• antibiotic delivery. A library of mono-, bis- and tris-catechol phenothiazine–siderophore conjugates are currently being prepared using this route. Their synthesis and MIC values against pathogenic mycobacteria, Gram-negative bacteria and Gram-positive bacteria, along with compound 11, will be reported in

Targeting the Pseudomonas quinolone signal quorum sensing system for the discovery of novel anti-infective pathoblockers

• Christian Schütz and
• Martin Empting

Beilstein J. Org. Chem. 2018, 14, 2627–2645, doi:10.3762/bjoc.14.241

• infections [2]. Especially in the case of Gram-negative bacteria, an urgent need for novel medicines has been identified while the pipeline of drug candidates is literally running dry and a desirable renaissance of the golden age of antibiotic drug research in ‘big pharma’ is currently not to be seen on the

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

• Gram-positive bacteria. While Gram-positive bacteria often use peptides as signal molecules, Gram-negative bacteria employ N-acylhomoserine lactones (AHLs) with subtle differences in their chemical structure, as well as other types of autoinducers (Figure 5). Interestingly, the signaling molecule

Synthesis of a leopolic acid-inspired tetramic acid with antimicrobial activity against multidrug-resistant bacteria

• Luce Mattio,
• Loana Musso,
• Leonardo Scaglioni,
• Andrea Pinto,
• Piera Anna Martino and
• Sabrina Dallavalle

Beilstein J. Org. Chem. 2018, 14, 2482–2487, doi:10.3762/bjoc.14.224

• antibacterial activity of compound 1 was tested on Staphylococcus pseudintermedius and Escherichia coli strains chosen as representative of Gram-positive and Gram-negative bacteria. In particular, we demonstrated the ability of compound 1 to inhibit Staphylococcus pseudintermedius strains expressing a multidrug

The enzymes of microbial nicotine metabolism

• Paul F. Fitzpatrick

Beilstein J. Org. Chem. 2018, 14, 2295–2307, doi:10.3762/bjoc.14.204

• closely related to the pyrrolidine pathway, with both found predominantly in Gram-negative bacteria [65]. This pathway is best characterized for Agrobacter tumefaciens S33, Ochrobactrum sp. SJY1, Sphingomonas melonis TY, and Shinella sp. HZN7, but has been identified in other bacteria as well [65][66][67

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

• [9][10]. The two Dec-NH2 analogs designed to fit a leucine zipper (LZ) template [25][26] presented the lowest hemolytic activity against red blood cells and maintained the antimicrobial activity of the parent template molecule vs Gram-positive bacteria, Gram-negative bacteria, and fungi. The authors

• -negative bacteria, fungi, and protozoa. However, both peptides presented high hemolytic activity, which limited their use as potential therapies. Torres et al. synthesized Dec-NH2 analogs with single and double substitutions, which exhibited increased resistance to degradation and lower hemolytic activity

• et al. described decoralin (Dec-Ser-Leu-Leu-Ser-Leu-Ile-Arg-Lys-Leu-Ile-Thr), an α-helical AMP from Oreumenes decoratus wasp venom [24]. In addition, the authors described its amidated analog (Dec-NH2), which displayed higher activity than its parent molecule against Gram-positive bacteria, Gram

Two new 2-alkylquinolones, inhibitory to the fish skin ulcer pathogen Tenacibaculum maritimum, produced by a rhizobacterium of the genus Burkholderia sp.

• Dandan Li,
• Naoya Oku,
• Atsumi Hasada,
• Masafumi Shimizu and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2018, 14, 1446–1451, doi:10.3762/bjoc.14.122

• [21][22][23][24][25], Gram-positive [26][27] and Gram-negative bacteria [28][29][30], and a marine sponge [31]. Among a variety of substituted 4-quinolones, 2-alkyl-4-quinolones are the most common core in antibiotics [32], which were originally discovered as anti-anthrax metabolites produced by

Aminosugar-based immunomodulator lipid A: synthetic approaches

• Alla Zamyatina

Beilstein J. Org. Chem. 2018, 14, 25–53, doi:10.3762/bjoc.14.3

• Alla Zamyatina Department of Chemistry, University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria 10.3762/bjoc.14.3 Abstract The immediate immune response to infection by Gram-negative bacteria depends on the structure of a lipopolysaccharide (LPS, also known as

• major surface antigen of Gram-negative bacteria, a complex heterogeneous glycolipid lipopolysaccharide (LPS, or endotoxin) [2][3], is recognised by a receptor complex composed of Toll-like Receptor 4 (TLR4) and a co-receptor protein myeloid differentiation factor 2 (MD-2) which are expressed by

• mammalian immune cells such as macrophages, monocytes and dendritic cells [4]. LPS represents the major virulence factor of Gram-negative bacteria and is essential for bacterial survival. LPS constitutes the outer leaflet of the outer membrane of Gram-negative bacteria (Figure 1A) and possesses a complex

Binding abilities of polyaminocyclodextrins: polarimetric investigations and biological assays

• Marco Russo,
• Daniele La Corte,
• Annalisa Pisciotta,
• Serena Riela,
• Rosa Alduina and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2017, 13, 2751–2763, doi:10.3762/bjoc.13.271

• , can undergo a transient period of competence after a pretreatment with calcium chloride followed by a short heat or electric shock. The addition of CaCl2 promotes the binding of pDNA to the outer membrane of Gram-negative bacteria. The Ca2+ ions both attract the negatively charged DNA backbone and