作者: Balutowski, Adam ; Hurst, Logan R ; Rivera-Kohr, David A ; Fratti, Rutilio A ; Gokbayrak, Zeynep D ; Calderin, Jorge D. ; Kazmirchuk, Thomas D.D. ; Hurst, Logan R. ; Fratti, Rutilio A. ; Zhang, Chi ; Hrabak, Michael R ; Brett, Christopher L. ; Hrabak, Michael R. ; Kazmirchuk, Thomas D D ; Brett, Christopher L ; Rivera-Kohr, David A. ; Gokbayrak, Zeynep D. ; Calderin, Jorge D

Sphingolipids are essential in membrane trafficking and cellular homeostasis. Here, we show that sphingolipids containing very long-chain fatty acids (VLCFAs) promote homotypic vacuolar fusion in Saccharomyces cerevisiae. The elongase Elo3 adds the last two carbons to VLCFAs that are incorporated into sphingolipids. Cells lacking Elo3 have fragmented vacuoles, which is also seen when WT cells are treated with the sphingolipid synthesis inhibitor Aureobasidin-A. Isolated elo3Δ vacuoles show acidification defects and increased membrane fluidity, and this correlates with deficient fusion. Fusion arrest occurs at the tethering stage as elo3Δ vacuoles fail to cluster efficiently in vitro. Unlike HOPS and fusogenic lipids, GFP-Ypt7 does not enrich at elo3Δ vertex microdomains, a hallmark of vacuole docking prior to fusion. Pulldown assays using bacterially expressed GST-Ypt7 showed that HOPS from elo3Δ vacuole extracts failed to bind GST-Ypt7 while HOPS from WT extracts interacted strongly with GST-Ypt7. Treatment of WT vacuoles with the fluidizing anesthetic dibucaine recapitulates the elo3Δ phenotype and shows increased membrane fluidity, mislocalized GFP-Ypt7, inhibited fusion, and attenuated acidification. Together these data suggest that sphingolipids contribute to Rab-mediated tethering and docking required for vacuole fusion.

2024-02-29·BioMed Research International

Screening Marine Microbial Metabolites as Promising Inhibitors of Borrelia garinii: A Structural Docking Approach towards Developing Novel Lyme Disease Treatment

Article

作者: Alotaibi, Ghallab ; Sattar, Sadia ; Bahauddin, Ammar Abdulraheem ; Basharat, Zarrin ; Al Mouslem, Abdulaziz K

Lyme disease caused by the Borrelia species is a growing health concern in many parts of the world. Current treatments for the disease may have side effects, and there is also a need for new therapies that can selectively target the bacteria. Pathogens responsible for Lyme disease include B. burgdorferi, B. afzelii, and B. garinii. In this study, we employed structural docking-based screening to identify potential lead-like inhibitors against the bacterium. We first identified the core essential genome fraction of the bacterium, using 37 strains. Later, we screened a library of lead-like marine microbial metabolites (

n = 4730

) against the arginine deiminase (ADI) protein of Borrelia garinii. This protein plays a crucial role in the survival of the bacteria, and inhibiting it can kill the bacterium. The prioritized lead compounds demonstrating favorable binding energies and interactions with the active site of ADI were then evaluated for their drug-like and pharmacokinetic parameters to assess their suitability for development as drugs. Results from molecular dynamics simulation (100 ns) and other scoring parameters suggest that the compound CMNPD18759 (common name: aureobasidin; IUPAC name: 2-[(4R,6R)-4,6-dihydroxydecanoyl]oxypropan-2-yl (3S,5R)-3,5-dihydroxydecanoate) holds promise as a potential drug candidate for the treatment of Lyme disease, caused by B. garinii. However, further experimental studies are needed to validate the efficacy and safety of this compound in vivo.

2023-08-25·Journal of natural products

Persephacin Is a Broad-Spectrum Antifungal Aureobasidin Metabolite That Overcomes Intrinsic Resistance in Aspergillus fumigatus.

Article

作者: Srivastava, Shikha ; Wendt, Karen L ; King, Jarrod B ; You, Jianlan ; Cunningham, Chad ; Mattes, Allison O ; Cichewicz, Robert H ; Haldar, Saikat ; Du, Lin

Fungi pose a persistent threat to humankind with worrying indications that emerging and re-emerging pathogens (e.g., Candida auris, Coccidioides spp., drug-resistant Aspergilli, and more) exhibit resistance to the limited number of approved antifungals. To address this problem, our team is exploring endophytic fungi as a resource for the discovery of new antifungal natural products. The rationale behind this decision is based on evidence that endophytes engage with plants in mutualistic relationships wherein some fungi actively participate by producing chemical defense measures that suppress pathogenic microorganisms. To improve the odds of bioactive metabolite discovery, we developed a new hands-free laser-cutting system capable of generating >50 plant samples per minute that, in turn, enabled our team to prepare and screen large numbers of endophytic fungi. One of the fungal isolates obtained in this way was identified as an Elsinoë sp. that produced a unique aureobasidin analogue, persephacin (1). Some distinctive features of 1 are the absence of both phenylalanine residues combined with the incorporation of a novel amino acid residue, persephanine (9). Compound 1 exhibits potent antifungal effects against a large number of pathogenic yeast (including several clinical C. auris strains), as well as phylogenetically diverse filamentous fungi (e.g., Aspergillus fumigatus). In an ex vivo eye infection model, compound 1 outperformed standard-of-care treatments demonstrating the ability to suppress fluconazole-resistant Candida albicans and A. fumigatus at a concentration (0.1% solution) well below the clinically recommended levels used for fluconazole and natamycin (2% and 5% solutions, respectively). In 3D tissue models for acute dermal and ocular safety, 1 was found to be nontoxic and nonirritating at concentrations required to elicit antifungal activity. Natural product 1 appears to be a promising candidate for further investigation as a broad-spectrum antifungal capable of controlling a range of pathogens that negatively impact human, animal, and plant health.

100 项与 Basifungin 相关的药物交易

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