Antibiofilm and cytotoxic metabolites from the entomopathogenic fungus Samsoniella aurantia

• Rita Toshe,
• Syeda J. Khalid,
• Blondelle Matio Kemkuignou,
• Esteban Charria-Girón,
• Paul Eckhardt,
• Birthe Sandargo,
• Kunlapat Nuchthien,
• J. Jennifer Luangsa-ard,
• Till Opatz,
• Hedda Schrey,
• Sherif S. Ebada and
• Marc Stadler

Beilstein J. Org. Chem. 2025, 21, 327–339, doi:10.3762/bjoc.21.23

• activity, inhibiting approximately 70% of Staphylococcus aureus biofilms at concentrations as low as 3.9 µg/mL. Keywords: antibiofilm; antiproliferative; beauvericin; insect pathogen; Samsoniella; Introduction A microbial biofilm represents an assemblage of planktonic cells to overcome hostile living

• conditions on either biotic or abiotic surfaces. Structurally, biofilms are polymicrobial consortia embedded in an extracellular polymeric substance (EPS) that plays a pivotal role in surface adhesion, enhancement of gene exchange, antimicrobial resistance, and protection against host immune and inflammatory

• and five 2-pyridone derivatives that revealed potential antibiofilm activity against Staphylococcus aureus biofilms [7]. These results encouraged us to explore a member of the Cordycipitaceae, in the genus Samsoniella that was segregated from Akanthomyces based on morphological and molecular evidence

Discovery of ianthelliformisamines D–G from the sponge Suberea ianthelliformis and the total synthesis of ianthelliformisamine D

• Sasha Hayes,
• Yaoying Lu,
• Bernd H. A. Rehm and
• Rohan A. Davis

Beilstein J. Org. Chem. 2024, 20, 3205–3214, doi:10.3762/bjoc.20.266

• data analyses. All compounds were assessed for their inhibition on planktonic growth of P. aeruginosa PAO1 in addition to their ability to inhibit the formation of biofilms. None of the tested natural products inhibited planktonic growth or biofilm formation of PAO1 when screened at 50 µM

• published with their antibiotic assessment against numerous bacterial species reported [8][9][10][11]. Our recent publication showed that of the naturally occurring metabolites, compound 3 inhibits the formation of P. aeruginosa PAO1 biofilms (MIC 53.1 µg/mL), whilst 1 and 2 enhanced the antibiotic effect

• undertook the first total synthesis of this natural product, which was successfully achieved in only three steps and respectable yield. All newly identified metabolites were subsequently assessed for their ability to inhibit the growth of planktonic P. aeruginosa PAO1 and formation of biofilms. Results and

A new glance at the chemosphere of macroalgal–bacterial interactions: In situ profiling of metabolites in symbiosis by mass spectrometry

• Marine Vallet,
• Filip Kaftan,
• Veit Grabe,
• Fatemeh Ghaderiardakani,
• Simona Fenizia,
• Aleš Svatoš,
• Georg Pohnert and
• Thomas Wichard

Beilstein J. Org. Chem. 2021, 17, 1313–1322, doi:10.3762/bjoc.17.91

• the algal host and the locally released and exchanged compounds within the algal chemosphere [3]. Bacterial biofilms on macroalgae can be crucial for developing algae and their interactions with other marine organisms. The exchange of resources in this spatially limited region is of high interest for

• is an important part of the MALDI-MSI experiment. MALDI-MS can be used to identify proteins and metabolic signatures [22][23][24] from bacteria and microalgae, as well as biofilms [25]. The primary function of the applied matrix is to improve the quality of the MS spectra, particularly the signal

Pigmentosins from Gibellula sp. as antibiofilm agents and a new glycosylated asperfuran from Cordyceps javanica

• Soleiman E. Helaly,
• Wilawan Kuephadungphan,
• Patima Phainuphong,
• Mahmoud A. A. Ibrahim,
• Kanoksri Tasanathai,
• Suchada Mongkolsamrit,
• Janet Jennifer Luangsa-ard,
• Souwalak Phongpaichit,
• Vatcharin Rukachaisirikul and
• Marc Stadler

Beilstein J. Org. Chem. 2019, 15, 2968–2981, doi:10.3762/bjoc.15.293

• -floating) cells, leading to an occurrence of reinfection once the antibiotic therapy is terminated [3][4][5]. In recent years, efforts to find new molecules that can selectively inhibit biofilms have steadily increased, based on the hypothesis that new agents can effectively disrupt biofilm formation and

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

• (B. subtilis), S. aureus, methicillin-resistant S. aureus (MRSA), and Micrococcus luteus (M. luteus). In the antimicrobial assay, compounds 3 and 5 were observed to interfere with the formation of biofilms commonly associated with S. aureus. When compounds 3 and 5 were evaluated for biofilm

Convergent synthesis of the pentasaccharide repeating unit of the biofilms produced by Klebsiella pneumoniae

• Arin Gucchait,
• Angana Ghosh and
• Anup Kumar Misra

Beilstein J. Org. Chem. 2019, 15, 431–436, doi:10.3762/bjoc.15.37

• unit of biofilms produced by Klebsiella pneumoniae, has been synthesized using a stereoselective [2 + 3] convergent glycosylation strategy. The β-D-mannosidic moiety has been synthesized using a D-mannose-derived thioglycoside by a two-step activation process. Late stage TEMPO-mediated oxidation of the

• pentasaccharide derivative using phase-transfer reaction conditions furnished the target compound in satisfactory yield. Keywords: beta-D-mannoside; biofilms; D-glucuronic acid; glycosylation; Klebsiella pneumoniae; pentasaccharide; polysaccharide; Introduction Klebsiella pneumoniae (K. pneumoniae) is a Gram

• -antigens [4]. The pathogenicity of K. pneumoniae relies on the structure of the capsular polysaccharides [5]. Besides a large number of polysaccharides present in the capsules, K. pneumoniae secrets a variety of polysaccharides which form biofilms for the protection of the organism from external agents [6

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

• most of HHQ and PQS derivatives showed no or only very weak effects on the growth of S. aureus, NMe-PQS (12) caused a similar growth inhibition as HQNO. However, the AQs did not significantly affect the formation of static biofilms of S. aureus under the conditions tested (see Figure S1, Supporting

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

• bacteria, which is crucial for the formation of well-organized superstructures such as biofilms. In contrast to eukaryotic lectins, bacterial lectins commonly occur in the form of filamentous protein appendages projecting from their surface, known as fimbriae and pili [63]. Fimbriae are present in high

• role of this lectin in bacterial physiology [100]. FHA also promotes the formation of biofilms by mediating cell–substrate and interbacterial adhesions [101]. Singh et al. reported that the products of four genes of the Mtb strain H37Rv: Rv0355, Rv1917, Rv3343, and Rv3350, show varying levels of amino

• shown that MTP is associated with Mtb aggregation and biofilm formation in vitro [116]. The importance of these interactions in patients, however, has yet to be confirmed, as the association of mycobacterial biofilms with bacterial pathogenesis has not yet been conclusively shown in vivo. Besides

Repurposing the anticancer drug cisplatin with the aim of developing novel Pseudomonas aeruginosa infection control agents

• Mingjun Yuan,
• Song Lin Chua,
• Yang Liu,
• Daniela I. Drautz-Moses,
• Joey Kuok Hoong Yam,
• Thet Tun Aung,
• Roger W. Beuerman,
• May Margarette Santillan Salido,
• Stephan C. Schuster,
• Choon-Hong Tan,
• Michael Givskov,
• Liang Yang and
• Thomas E. Nielsen

Beilstein J. Org. Chem. 2018, 14, 3059–3069, doi:10.3762/bjoc.14.284

• the secretion of exotoxins. Furthermore, cisplatin was also demonstrated to eradicate in vitro biofilms and in vivo biofilms in a murine keratitis model. This showed that cisplatin could be effectively used to eradicate biofilm infections which were otherwise difficult to be treated by conventional

• the main cause of fatal infections in patients with cystic fibrosis (CF) [2] and cancer patients [3][4]. The success of P. aeruginosa as a leading pathogen is attributed to its ability to form resilient biofilms, resist antimicrobials and secrete virulence products. Microbial cells resident in

• biofilms are encased by an extracellular matrix, which protects them from antimicrobial treatment and the host’s immune clearance [5]. Clinical P. aeruginosa isolates are mostly multidrug-resistant (MDR) strains [6], with robust ability to form biofilms [7]. P. aeruginosa also secretes virulence factors

Synthesis of pyrrolidine-based hamamelitannin analogues as quorum sensing inhibitors in Staphylococcus aureus

• Jakob Bouton,
• Kristof Van Hecke,
• Reuven Rasooly and
• Serge Van Calenbergh

Beilstein J. Org. Chem. 2018, 14, 2822–2828, doi:10.3762/bjoc.14.260

• ), an inhibitor of the RAP/TRAP (RNAIII-activating protein/target of RAP) quorum sensing system in S. aureus (Figure 1) [12][13][14]. Furthermore, hamamelitannin has been shown to inhibit biofilm formation and to potentiate the activity of antibiotics against staphylococcal biofilms in vitro and in vivo

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

• cells in biofilms with anaerobic conditions [44]. Due to these important virulence mechanisms, which are under direct or indirect control of pqs QS, targeting this master regulatory system with small molecular compounds, thereby blocking P. aeruginosa pathogenicity, is very attractive. However, this

• antibiofilm effects of two clinically relevant drugs. When growing biofilms for 48 h in presence or absence of M64 (42), followed by treatment of 10 µg/mL of meropenem or tobramycin for 24 h, the activity of the otherwise ineffective antibiotics could be restored. Especially in the case of meropenem, which

• pathoblockers is quite promising. Specifically, it has been shown that PqsR-targeting QSI are able to increase the susceptibility of P. aeruginosa biofilms against antibiotics [78]. Hence, adjunctive treatment approaches where a conventional backbone antibiotic therapy is potentiated by pathoblocking agents

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

• that, in addition to antimicrobial resistance, forms biofilms, a complex matrix of extracellular polysaccharides, polypeptides and DNA, which act as an additional protective barrier [30]. P. aeruginosa employs two lectins for biofilm formation and host–cell adhesion: proteins LecA and LecB [31][32

• inhalative administration [46]. Despite its LecB-mediated in vivo activity, this compound had no effect on biofilms in vitro at concentrations up to 2000-fold above the Kd; a biofilm reduction by 80% could be achieved at concentrations as high as 100000-fold above Kd (5 mM). For a future systemic application

• , or the formation of bacterial biofilms, can be inhibited. Numerous reviews have detailed these processes addressing various QS pathways [30][72][73]. The antibiotic azithromycin (22), which does not have significant bactericidal activity for P. aeruginosa, but interferes with its quorum sensing

Impact of Pseudomonas aeruginosa quorum sensing signaling molecules on adhesion and inflammatory markers in endothelial cells

• Carmen Curutiu,
• Florin Iordache,
• Veronica Lazar,
• Aurelia Magdalena Pisoschi,
• Aneta Pop,
• Mariana Carmen Chifiriuc and
• Alina Maria Hoban

Beilstein J. Org. Chem. 2018, 14, 2580–2588, doi:10.3762/bjoc.14.235

• central regulator mechanism of virulence expression that contributes to the formation and maintenance of biofilms and tolerance to conventional antimicrobials. QS Signaling molecules (QSSMs) may be recognized and may function also within the host cells, being potentially involved in the progression of the

• Pseudomonas biofilms and even biofilm survival [6]. The las system is indispensable for the development of a normal biofilm, including the differentiation of biofilm-like structures (such as “mushrooms” and "columns") observed in biofilms developed in vitro [7]. Some studies have shown that QS-deficient

• mutant strains initially form biofilms with the same dense structure as wild strains. The mutant strains produce even "mushroom"-like structures similar to wild strains that have as carbon source, glucose, but compared to wild type, mature biofilms (10 or more days of development) produced by QS

Defining the hydrophobic interactions that drive competence stimulating peptide (CSP)-ComD binding in Streptococcus pneumoniae

• Bimal Koirala,
• Robert A. Hillman,
• Erin K. Tiwold,
• Michael A. Bertucci and
• Yftah Tal-Gan

Beilstein J. Org. Chem. 2018, 14, 1769–1777, doi:10.3762/bjoc.14.151

• from the environment by forming biofilms [22][23][24][25][26][27]. The competence regulon in S. pneumoniae is therefore a major regulator of pathogenicity and thus a potential target for attenuating S. pneumoniae infections. S. pneumoniae strains can be divided into two main specificity groups based on

What contributes to an effective mannose recognition domain?

• Christoph P. Sager,
• Deniz Eriş,
• Martin Smieško,
• Rachel Hevey and
• Beat Ernst

Beilstein J. Org. Chem. 2017, 13, 2584–2595, doi:10.3762/bjoc.13.255

• glycosides on mammalian cell surfaces. After this initial contact, they can infect host cells and form biofilms, both of which are key factors for their survival [9][27][28]. Examples of such opportunistic bacterial species binding to mannosides on host cells include Pseudomonas aeruginosa with its membrane

Glyco-gold nanoparticles: synthesis and applications

• Federica Compostella,
• Olimpia Pitirollo,
• Alessandro Silvestri and
• Laura Polito

Beilstein J. Org. Chem. 2017, 13, 1008–1021, doi:10.3762/bjoc.13.100

• -antibiotic conjugates, were prepared and resulted able to overcome antibiotic resistance of microbial biofilms, since CA NPs render streptomycin more accessible to biofilms, thereby more available to interact with biofilm bacteria [89]. Similarly, a novel recyclable E.coli-specific killing GAuNP

Organic chemistry meets polymers, nanoscience, therapeutics and diagnostics

• Vincent M. Rotello

Beilstein J. Org. Chem. 2016, 12, 1638–1646, doi:10.3762/bjoc.12.161

• (through mutation or glycolosis) generate very strong sensor responses, implicating that our sensor responds to changes in glycosylation [86] which is probably also the mechanism in play for our successful determination of biofilms using this platform [87]. Whither next? You can probably tell from the

• -resistant bacteria such as MRSA [90] and nanocapsule systems work against the biofilms [91] made by these nasties [92]. We have also made a foray into bioorthogonal chemistry, using nanoparticles to encapsulate transition metal catalysts, generating “nanozymes” that can catalyze processes in cells that even

Discovery of an inhibitor of the production of the Pseudomonas aeruginosa virulence factor pyocyanin in wild-type cells

• Bernardas Morkunas,
• Balint Gal,
• Warren R. J. D. Galloway,
• James T. Hodgkinson,
• Brett M. Ibbeson,
• Yaw Sing Tan,
• Martin Welch and
• David R. Spring

Beilstein J. Org. Chem. 2016, 12, 1428–1433, doi:10.3762/bjoc.12.137

• antibiotic-resistant biofilms [7][8][9]. The incidence of multidrug-resistant P. aeruginosa infections is on the rise on a global scale [8][9][10] and this bacterium is now considered to have joined the ranks of the ‘superbugs’ [1]. Thus, there is an urgent need to discover new therapeutic strategies to

Expeditive synthesis of trithiotriazine-cored glycoclusters and inhibition of Pseudomonas aeruginosa biofilm formation

• Meriem Smadhi,
• Sophie de Bentzmann,
• Anne Imberty,
• Marc Gingras,
• Raoudha Abderrahim and
• Peter G. Goekjian

Beilstein J. Org. Chem. 2014, 10, 1981–1990, doi:10.3762/bjoc.10.206

• particular due to the physical barrier created by surface-attached biofilms, thus limiting antibiotic penetration [4][5][6]. A challenging and useful task is therefore to develop novel strategies against PA colonies at this late stage of virulence. Among recent approaches, targeting biofilm formation or

• lectins in the form of glycoclusters [17], poly(glycomer)s [18][19][20][21], and glycodendrimers [22][23][24]. In regards to PA, C-fucosylpeptide dendrimers were shown to inhibit biofilm formation and to efficiently disperse established biofilms in both reference and hospital strains of PA [25][26][27

• ]. Recently, galactosylated peptide dendrimers have shown a strong affinity for lecA while inhibiting or dispersing biofilms [28][29]. This anti-biofilm effect mediated by glycodendrimers validates a new approach to the control PA propagation and infection. In this work and following those lines, we had in

Algicidal lactones from the marine Roseobacter clade bacterium Ruegeria pomeroyi

• Ramona Riclea,
• Julia Gleitzmann,
• Hilke Bruns,
• Corina Junker,
• Barbara Schulz and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2012, 8, 941–950, doi:10.3762/bjoc.8.106

• symbionts [3][4] or associated with molluscs [5]; and can form biofilms [6]. Particularly interesting from an ecological point of view is their association with marine algae, such as dinoflagellates and coccolithophores, which produce large amounts of the sulfur metabolite dimethylsulfoniopropionate (1

Synthetic glycopeptides and glycoproteins with applications in biological research

• Ulrika Westerlind

Beilstein J. Org. Chem. 2012, 8, 804–818, doi:10.3762/bjoc.8.90

• L-fucose IC50 = 11 μM) [106]. The glycopeptide dendrimer was able to completely inhibit P. aeruginosa biofilm formation at a concentration of 50 μM and established biofilms from wild-type strain and clinical isolates could be completely dispersed. In a later study, analogues of FD2 49 were prepared

Conserved and species-specific oxylipin pathways in the wound-activated chemical defense of the noninvasive red alga Gracilaria chilensis and the invasive Gracilaria vermiculophylla

• Martin Rempt,
• Florian Weinberger,
• Katharina Grosser and
• Georg Pohnert

Beilstein J. Org. Chem. 2012, 8, 283–289, doi:10.3762/bjoc.8.30

• peruviana as a model herbivore to monitor the role of the oxylipins in the chemical defence of the algae. This snail is highly abundant on Chilean and Peruvian coasts where G. chilensis is native and can reach population densities of up to 2000 individuals/m2 [7]. E. peruviana is known to graze on biofilms

A bivalent glycopeptide to target two putative carbohydrate binding sites on FimH

• Thisbe K. Lindhorst,
• Kathrin Bruegge,
• Andreas Fuchs and
• Oliver Sperling

Beilstein J. Org. Chem. 2010, 6, 801–809, doi:10.3762/bjoc.6.90

• persistent biofilms. In all cases of bacterial adhesion and of biofilm formation severe health problems can result for the host organism [1][2]. A number of microbial adhesins are known, that co-operate in the adhesion process [3], such as the fimbriae, which are long filamentous adhesive organells on the