Biological Studies Research Articles

In Vivo-Active Soluble Epoxide Hydrolase-Targeting PROTACs with Improved Potency and Stability.

Soluble epoxide hydrolase (sEH) is a bifunctional enzyme involved in fatty acid metabolism and a promising drug target. We previously reported first-generation sEH proteolysis-targeting chimeras (PROTACs) with limited degradation potency and low aqueous and metabolic stability. Herein, we report the development of next-generation sEH PROTAC molecules with improved stability and degradation potency. One of the most potent molecules (compound 8) exhibits a half-maximal degradation concentration in the sub-nM range, is stable in vivo, and effectively degrades sEH in mouse livers and brown adipose tissues. Given the role played by sEH in many metabolic and nonmetabolic diseases, the presented molecules provide useful chemical probes for the study of sEH biology. They also hold potential for therapeutic development against a range of disease conditions, including diabetes, inflammation, and metabolic disorders.

Design, synthesis and biological studies of new isoxazole compounds as potent Hsp90 inhibitors

Heat shock protein 90 (Hsp90), a molecular chaperone, contributes to the preservation of folding, structure, stability, and function proteins. In this study, novel compounds comprising isoxazole structure were designed, synthesized and their potential ability as Hsp90 inhibitors was validated through docking studies. The active site-based compounds were prepared through a multi-step synthesis process and their chemical structures were characterized employing FT-IR, NMR, and mass spectrometry analysis. Cytotoxic and Hsp90 inhibition activities of synthesized compounds were assessed by MTT assay and ELISA kit, respectively. Based on the obtained results, compound 5 exhibited the highest cytotoxicity (IC50; 14 µM) against cancer cells and reduced Hsp90 expression from 5.54 ng/mL in untreated (normal cells) to 1.56 ng/mL in cancer cells. Moreover, molecular dynamics (MD) simulation results indicated its high affinity to target protein and approved its excellent stability which is essential for exerting an inhibitory effect on cancer cell proliferation.

Turkish Astragalus Species: Botanical Aspects, Secondary Metabolites, and Biotransformation.

Astragalus is a widespread genus comprising approximately 3500 species, both annual and perennial, found across Asia, Europe, Africa, and the Americas. In Turkey, it is represented by 63 sections and 485 taxa with a high endemism ratio (51%). In traditional medicine, the roots of various Astragalus species represent very old and well-known drugs used for antiperspirant, diuretic, and tonic purposes, as well as for the treatment of nephritis, diabetes, leukemia, and uterine cancer. The genus Astragalus is the richest source of cycloartane-type compounds, which display a diverse range of bioactivities, such as wound healing, immunomodulatory, antitumor, hepatoprotective, antimutagenic, antiviral, and antiprotozoal activities. Moreover, cycloastragenol, the main sapogenol of many cycloartane-type glycosides found in the Astragalus genus, has gained attention as a potent telomerase activator over the past decade. The preparation of cycloastragenol derivatives could be significant in the near future due to their unique bioactivity. This review covers the botanical aspects of Astragalus L., as well as the phytochemical and biological activity studies conducted on Turkish Astragalus species, with a special focus on cycloartenols. It contains 36 articles reporting the phytochemistry of 29 Astragalus species and 111 new compounds, including 104 triterpene saponins. In addition to the phytochemical studies, this review summarizes the biotransformation studies on Astragalus cycloartanes via endophytic fungi isolated from the tissues of Astragalus species.

Arenicolide Family Macrolides Provide a New Therapeutic Lead Combating Multidrug‐Resistant Tuberculosis

AbstractThe emergence of multidrug‐resistant (MDR) and extensively drug‐resistant (XDR) strains of Mycobacterium tuberculosis (Mtb) poses a significant threat to health globally. During searching for new chemical entities regulating MDR‐ and XDR‐Mtb, chemical investigation of the black oil beetle gut bacterium Micromonospora sp. GR10 led to the discovery of eight new members of arenicolides along with the identification of arenicolide A (Ar−A, 1), which was a previously reported macrolide with incomplete configuration. Genomic analysis of the bacterial strain GR10 revealed their putative biosynthetic pathway. Quantum mechanics‐based computation, chemical derivatizations, and bioinformatic analysis established the absolute stereochemistry of Ar−A and arenicolides D−K (Ar−D−K, 2–9) completely for the first time. Biological studies of 1–9 revealed their antimicrobial activity against MDR and XDR strains of Mtb. Ar−A had the most potent in vitro antimicrobial efficacy against MDR‐ and XDR‐Mtb. Mechanistically, Ar−A induced ATP depletion and destabilized Mtb cell wall, thereby inhibiting growth. Notably, Ar−A exerted a significant antimicrobial effect against Mtb in macrophages, was effective in the treatment of Mtb infections, and showed a synergistic effect with amikacin (AMK) in a mouse model of MDR‐Mtb lung infection. Collectively, our findings indicate Ar−A to be a promising drug lead for drug‐resistant tuberculosis.

Arenicolide Family Macrolides Provide a New Therapeutic Lead Combating Multidrug-Resistant Tuberculosis.

The emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains of Mycobacterium tuberculosis (Mtb) poses a significant threat to health globally. During searching for new chemical entities regulating MDR- and XDR-Mtb, chemical investigation of the black oil beetle gut bacterium Micromonospora sp. GR10 led to the discovery of eight new members of arenicolides along with the identification of arenicolide A (Ar-A, 1), which was a previously reported macrolide with incomplete configuration. Genomic analysis of the bacterial strain GR10 revealed their putative biosynthetic pathway. Quantum mechanics-based computation, chemical derivatizations, and bioinformatic analysis established the absolute stereochemistry of Ar-A and arenicolides D-K (Ar-D-K, 2-9) completely for the first time. Biological studies of 1-9 revealed their antimicrobial activity against MDR and XDR strains of Mtb. Ar-A had the most potent in vitro antimicrobial efficacy against MDR- and XDR-Mtb. Mechanistically, Ar-A induced ATP depletion and destabilized Mtb cell wall, thereby inhibiting growth. Notably, Ar-A exerted a significant antimicrobial effect against Mtb in macrophages, was effective in the treatment of Mtb infections, and showed a synergistic effect with amikacin (AMK) in a mouse model of MDR-Mtb lung infection. Collectively, our findings indicate Ar-A to be a promising drug lead for drug-resistant tuberculosis.

Mitochondrial reactive oxygen species-mediated fibroblast activation has a role in tumor microenvironment formation in radiation carcinogenesis.

Cancer risks attributable to low-dose and low-dose-rate radiation are a serious concern for public health. Radiation risk assessment is based on lifespan studies among Hiroshima-Nagasaki A-bomb survivors; however, there are statistical limitations due to a small sample size for low-dose radiation. Therefore, basic biological studies are helpful in understanding the mechanism of radiation carcinogenesis. The detrimental effects of ionising radiation (IR) are caused by reactive oxygen species (ROS)-mediated oxidative DNA damage. IR-induced delayed ROS are produced in the electron transport chain reaction of the mitochondrial complex. Thus, mitochondria are a source of ROS and a primary target for ROS attacks. Consequently, mitochondrial dysfunction is thought to be a key event in the metabolic changes of cancer cells and is important in radiation-induced carcinogenesis. In this paper, we present recent findings on radiation carcinogenesis effect assessment, focusing on mitochondrial function as stress sensors.

Green Synthesis of New Spiropyrrole Derivatives by Employing Activated Carbonyl Compounds and Graphen Oxide Decorated on Ag@CuO/ZnO NPs or CuO/ZnO NPs: Theoretical and Biological Study

ABSTRACTThis study focused on investigating the synthesis of new spiropyrrole derivatives with high yields. The two nanocatalyst CuO/ZnO@Graphen Oxide nanocomposites (CuO/ZnO@GO NCs) and Ag/CuO/ZnO@Graphen Oxide (Ag@CuO/ZnO@GO NCs) were employed in a multicomponent reaction at room temperature to synthesize new compounds. The reaction involved isatins, N‐alkyl isatins, and ninhydrin as activated carbonyl compounds, ammonium acetate, ethyl 2‐arylamino‐4‐dioxo‐4‐arylbutanoates, hydrazonoyl chloride, or ethylbromopyruvate in water. Also, the catalytic activity of the green synthesized CuO/ZnO@GO and Ag@CuO/ZnO@GO was evaluated in the reduction of organic pollutants such as 4‐nitrophenol (4‐NP) in water at mild conditions. The results indicated that the biosynthesized MNCs have very high and effective catalytic activity for organic pollutants within a few seconds. The newly synthesized spiro compounds demonstrate antioxidant activity as a result of two assessment processes conducted by its NH group. In addition, the antibacterial activity of newly created spiro compounds was assessed using a disk distribution method, involving two types of Gram‐negative bacteria. These compounds were found to limit the growth of Gram‐positive bacteria as well. Also, to better understand the reaction mechanism, density functional theory (DFT)–based quantum chemical methods have been applied. The advantages of this technology encompass rapid response times, high product yields, and uncomplicated catalyst and product separation via simple procedures.

Myocarditis in children. Modern aspects of diagnostics

Introduction. A review of the current literature on the features of the diagnosis of myocarditis in children is presented. Myocarditis is an acute or chronic inflammatory myocardial disease characterized by a variety of clinical manifestations, nonspecific symptoms and physical data. With insufficient number of informative diagnostic tests, there is a challenge for practitioners at all stages of medical care. Aim of the review is to comprehensively present the features of the clinical diagnosis of myocarditis in children. The presence of myocarditis should be assumed in situations where children, regardless of the age, first developed symptoms of heart failure (HF), as well as in the presence of a clinic of viral infections accompanied by respiratory or abdominal symptoms, combined with the development of tachycardia, hypotension or cardiac arrhythmias, even in the absence of cardiomegaly. Myocarditis should be clinically suspected at the stage when the necessary decisions should be made about the patient’s routing, the formation of a complex of diagnostic examinations and the start of therapy. Magnetic resonance imaging (MRI) of the heart is today the non-invasive gold standard for the diagnosis of myocarditis that allows detecting myocarditis within 2–3 weeks after the first symptoms appear. Endomyocardial biopsy can be used for accurate morphological diagnosis of myocarditis in children. Molecular biological and genetic studies that determine the severity and outcome of the disease are important for the diagnosis of myocarditis in children. Conclusion. Based on the literature data and own experience in diagnosing myocarditis, the authors have developed an original diagnostic algorithm to make the right medical decision in case of suspected acute myocarditis in children.

Emergence of hypervirulent and carbapenem-resistant Klebsiella pneumoniae from 2014 - 2021 in Central and Eastern China: a molecular, biological, and epidemiological study

BackgroundIn recent years, the hypervirulent and carbapenem-resistant Klebsiella pneumoniae has been increasingly reported worldwide. The objective of this study was to compare the antibiotic resistance and virulence profiles of carbapenem-resistant hypervirulent K.pneumoniae (CR-hvKP) and hypervirulent carbapenem-resistant K.pneumoniae (hv-CRKP) and identify the prevailing strain in clinical settings.MethodsIn this study, hv-CRKP or CR-hvKP were identified based on the results of whole-genome analysis (WGS), multilocus sequence typing (MLST) and the antimicrobial susceptibility testing. We then compared antibiotic resistance and virulence profiles between CR-hvKP and hv-CRKP through the antimicrobial susceptibility testing and a series of virulence experiments including biofilm formation ability detection method, the resistance test against human serum, siderophore production test, neutrophil phagocytosis assay and Galleria mellonella infection model. Additionally, pathway enrichment analysis was conducted to assess the effect of SNPs on the phenotype.ResultsIn this study, we categorized 17.4% of hypervirulent and carbapenem-resistant K. pneumoniae strains as CR-hvKP and 82.6% as hv-CRKP. Among them, 84.2% (16/19) of CR-hvKP strains harboring carbapenemase genes exhibited lower imipenem and meropenem MIC values compared to hv-CRKP strains. The virulence potential of hv-CRKP and CR-hvKP was confirmed by using virulence experiments in vitro and in vivo, showing that virulence of the CR-hvKP strains was comparable to that of hv-CRKP strains. Notably, the 90 hv-CRKP strains were classified into 3 different ST types and 8 capsule types, each showing varying degrees of resistance and virulence. We observed that subclonal replacement was within the predominant hv-CRKP clone, with the ST11-KL64 strain, characterized by high-level resistance and virulence emerging as the currently prevailing subclone, replacing ST11-KL47. KEGG enrichment analysis showed that pathways associated with the citrate cycle (TCA cycle), glycolysis/gluconeogenesis, glutathione metabolism, two-component regulatory system, and folate metabolism were significantly enriched among the group expressing different levels of capsular polysaccharides.ConclusionsThe hv-CRKP strains exhibited a greater survival advantage in the hospital environment than CR-hvKP strains. Notably, the ST11-KL64 hv-CRKP strain which displayed a high level of resistance and hypervirulence, warrants the most clinical vigilance.Clinical trial numberNot applicable.

Stability of the polarization agent AsymPolPOK in intact and lysed mammalian cells.

Dynamic nuclear polarization (DNP) solid-state NMR enables detection of proteins at endogenous concentrations in cells through sensitivity enhancement from nitroxide biradical polarization agents. AsymPolPOK, a novel water-soluble asymmetric nitroxide biradical, offers superior sensitivity and faster build-up times compared to existing agents like AMUPol. Here, we characterize AsymPolPOK in mammalian HEK293 cells, examining its cellular distribution, reduction kinetics, and DNP performance. We demonstrate that electroporation achieves uniform cellular delivery of AsymPolPOK, including nuclear permeation, with no cytotoxicity at millimolar concentrations. However, the cellular environment rapidly reduces AsymPolPOK to its monoradical form, with one nitroxide center showing greater reduction resistance than the other. While AsymPolPOK maintains high DNP enhancements and short build-up times in lysates, its performance in intact cells depends critically on delivery method and exposure time to cellular constituents. Electroporation yields higher, more uniform enhancements compared to incubation, but prolonged exposure to the cellular environment diminishes DNP performance in both cases. These findings establish the potential of AsymPolPOK as a polarization agent for in-cell DNP NMR while highlighting the need for developing more bio-resistant polarization agents to further advance cellular structural biology studies.

Brain Metastasis in Pediatric Patients with Osteosarcoma.

Brain metastases in pediatric osteosarcoma are infrequent but associated with a dire prognosis. This retrospective study examined six pediatric patients at Johns Hopkins Hospital who developed brain metastases from osteosarcoma between April 2015 and November 2023. Median survival post-brain metastasis was 2.5 months. The patients underwent various treatments, including chemotherapy, surgery, and radiation. Despite these interventions, outcomes were uniformly fatal. Notably, one patient survived over 13 months post-brain metastasis with a treatment regimen of cabozantinib and nivolumab along with surgical resection and radiation, highlighting the potential efficacy of multimodal treatment regimens. This case demonstrated changes in the immune microenvironment, hinting at an anti-tumoral response, although no histologic response was observed. These findings emphasize the critical need for vigilant clinical monitoring, especially in patients with new neurological symptoms. The study highlights the diagnostic challenges and the rapid progression of brain metastases, underscoring the necessity for further research. Prospective studies and clinical trials focusing on novel therapeutic strategies are essential to improve outcomes. Disease biology studies examining tumor features across primary, pulmonary, and brain metastatic sites may offer insights into the mechanisms of metastasis and potential therapeutic targets, providing a foundation for better management of this devastating complication.

Morphology, phylogeny, and mitogenomics reveal a new entomopathogenic fungus, Blackwellomyces changningensis (Hypocreales, Clavicipitaceae), from southwestern China

ABSTRACT Two species of Blackwellomyces (Clavicipitaceae, Hypocreales, Ascomycota) were discovered during an investigation of the diversity of entomopathogenic fungi. A new fungus and one known fungal species that were gathered from Yunnan Province were described in this study. Blackwellomyces changningensis, sp. nov. was described using morphology and phylogenetic evidence from 14 mitochondrial protein-coding gene (PCG) data sets (atp6, atp8, atp9, cob, cox1, cox2, cox3, nad1, nad2, nad3, nad4, nad5, nad6, and nad4L) and six nuclear genes (ITS [ITS4 and ITS5], 18S nuc rDNA [18S], 28S nuc rDNA [28S], tef1-α, rpb1, and rpb2). B. changningensis were found parasitic to Lepidoptera larvae and to produce filiform ascospores with septations. The asexual conidia were ovoid to ellipsoid in shape. Phylogenetic analysis and morphological observations concurred that the fungus belonged to a different species within the genus of Blackwellomyces. The foundation for further taxonomic, genetic, and evolutionary biological studies of the genus Blackwellomyces was laid by this work.

Engineering an Ultrasound-Responsive Glycopolymersome for Hepatocyte-Specific Gene Delivery.

The ability to design liver-targeted gene delivery vectors is plagued with difficulties ranging from carrier-mediated cellular toxicity to challenges in encapsulating sensitive nucleic acids. Herein, we present an ultrasound-responsive glycopolymersome strategy for in situ loading of nucleic acids and achieving hepatocyte-specific gene delivery. This glycopolymersome is self-assembled from a block copolymer, N-acetylgalactosamine-grafted poly(glutamic acid)-block-poly(ε-caprolactone) (PGAGalNAc-b-PCL). GalNAc is introduced to afford liver targeting through the selective binding to the asialoglycoprotein receptor overexpressed on hepatocytes. External ultrasound is utilized to assist in encapsulating nucleic acids within the hydrophilic lumen of glycopolymersomes by exploiting their ultrasound responsiveness nature. Biological studies confirmed the successful encapsulation of plasmid DNA (pDNA) and small interfering RNA (siRNA), rapid nuclear internalization, and efficient gene transfection. These findings collectively demonstrated that this ultrasound-responsive glycopolymersome could be exploited as a novel safe and efficient gene vector targeting hepatocytes.

Elaboration of a new 4-(4-nitrophenyl)piperazin-1-ium tetrakis(thiocyanato)-cobalt hydrate: Crystal structure, optical properties, quantum computational investigation, electrical and biological study

The preparation, spectroscopic, biological, and electrical characterization, in addition to the X-ray crystal structure investigation of a novel three-dimensional compound (C10H14N3O2)2 [Co(NCS)4].H2O ((NPP)2[Co(NCS)4].H2O) is reported. The synthesized compound crystallizes in the Pna21 space group. The structure comprises layers of cobalt (II) bridged by terminally bound thiocyanate-N ligand achieving distorted MN4 tetrahedron surroundings around the metal center. The vibrational modes of the functional groups were investigated using FT-IR measurements. Hirshfeld surface (HS) analysis and electronic structures calculations reveal the excellent reactivity and intermolecular interactions in stabilizing complex. The change transfer and NLO parameters were also computed using the DFT method. The study of the optical behavior reveals a high optical property. Explorations of impedance spectroscopy on (NPP)2[Co(NCS)4].H2O reveals fascinating electrical behavior which reveals that the Co complex component can be used as an electronic chip under certain conditions. The thermal analysis was used to confirm the crystal’s thermal stability. The compound’s antimicrobial activity suggested that the Cobalt complex acts as an inhibitor Agent against different types of bacteria.

Assessments and investigation of process parameter impacts on surface roughness, microstructure, tensile strength, and porosity of 3D printed polyetherether ketone (PEEK) materials

Additive manufacturing (AM) is emerging as a competitive technology with promising applications across various sectors, including biomedical, automotive, construction, and dental implants. This study investigates the influence of key process parameters on the surface roughness, microstructure, tensile strength, and porosity of Polyether Ether Ketone (PEEK), a high-performance thermoplastic used in dental prosthetics. Traditionally, metals and ceramics have been the standard for dental restorations, but advancements in computer-aided design (CAD) and computer-aided manufacturing (CAM) have improved accuracy, particularly for implant-supported prostheses. However, conventional methods like CAD-milling face challenges such as material waste and tool wear. AM techniques, such as fused deposition modeling (FDM), offer a solution by constructing objects layer by layer, minimizing waste. This research explores the effects of nozzle temperature on the mechanical properties of 3D-printed PEEK, emphasizing its role in optimizing performance and minimizing issues like porosity. Key factors like surface roughness and microstructure are highlighted as critical to the biocompatibility and longevity of dental restorations. The study identifies the optimal nozzle temperature range for PEEK 380–440 °C, noting that deviations from this range lead to compromised mechanical properties. Overall, the findings provide valuable insights into optimizing the AM process for PEEK in dental applications and suggest that further biological and chemical studies are necessary to fully realize the material's potential in replacing traditional dental restoration materials.

Complexation by γ-cyclodextrin as a way of improving anticancer potential of sumanene

Biological applications of sumanene buckybowl molecule have been widely discussed over the years yet remain still unexplored experimentally. On the other hand, creating cyclodextrin-containing supramolecular assemblies was demonstrated to be a powerful tool in terms of designing effective systems for medicinal chemistry purposes. Here, we show that sumanene molecule exclusively forms 1:1 host-guest complexes with γ-cyclodextrin (γCD) or (2-hydroxypropyl)-γ-cyclodextrin (HP-γCD), as revealed by extensive spectroscopic studies supported with density functional theory (DFT) computations. Based on our preliminary biological studies, we discovered that the formation of such complexes resulted in the improvement of anticancer properties of sumanene, expressed by high cell viabilities in vitro of healthy human mammary fibroblasts (HMF) together with low viabilities of human breast adenocarcinoma cells (MDA-MB-231). Improved pharmacokinetic (ADME-Tox) properties for sumanene@γCD and sumanene@HP-γCD complexes in comparison to native sumanene were also supported by in sillico modeling studies. This work provides the method how to focus the cytotoxic action of sumanene toward cancer cells using supramolecular assembly strategy, paving the way to the further exploration of biological properties of sumanene-containing supramolecular systems with bioactive features and applications of this buckybowl in general.

Cryo-EM structures of the membrane repair protein dysferlin

Plasma membrane repair in response to damage is essential for cell viability. The ferlin family protein dysferlin plays a key role in Ca2+-dependent membrane repair in striated muscles. Mutations in dysferlin lead to a spectrum of diseases known as dysferlinopathies. The lack of a structure of dysferlin and other ferlin family members has impeded a mechanistic understanding of membrane repair mechanisms and the development of therapies. Here, we present the cryo-EM structures of the full-length human dysferlin monomer and homodimer at 2.96 Å and 4.65 Å resolution. These structures define the architecture of dysferlin, ferlin family-specific domains, and homodimerization mechanisms essential to function. Furthermore, biophysical and cell biology studies revealed how missense mutations in dysferlin contribute to disease mechanisms. In summary, our study provides a framework for the molecular mechanisms of dysferlin and the broader ferlin family, offering a foundation for the development of therapeutic strategies aimed at treating dysferlinopathies.

Dynamics of AKAP/Calmodulin complex is largely driven by ionic occupancy state

AKAP79/150 is a scaffold protein found in dendritic spines and other neuronal compartments. It localizes and regulates phosphorylation by protein kinase A and C and is, in turn regulated by Ca2+, mediated by Calmodulin (CaM). Thus, the interaction of AKAP79/150 with CaM is of biological interest. A 2017 study used a peptide cross linking coupled to mass spectrometry (XLMS) to identify the CaM binding site on AKAP79/150 and subsequently solved an X-ray crystallography structure of CaM in complex with a short helical AKAP79/150 peptide. The XRD structure revealed an unusual mixed ionic occupancy state of CaM as bound to the AKAP79/150 peptide. In this molecular dynamics-based study, we have explored the motional modes of the CaM-AKAP helix complex under three ionic occupancy conditions. Our results indicate that the dynamics of this CaM backbone is largely dominated by the ionic occupancy state. We find that binding of the AKAP79/150 peptide to CaM is not preferentially stabilized in energetic terms in the Ca2+ state as compared to apo. However, the Mg2+ state is destabilized energetically as compared to the apo state. In addition, in the Ca2+ state, the AKAP79/150 peptide appears to be preferentially stabilized by additional hydrogen bonds. Our simulations suggest that further structural biology studies should be carried out, with a focus on driving the system equilibrium to full Ca2+ occupancy. NMR studies may be able to capture conformational states which are not seen in crystals.

Different transcriptomic and metabolomic analysis of Saccharomyces cerevisiae BY4742 and CEN.PK2-1C strains.

To establish efficient yeast cell factories, it is necessary to understand the transcriptional and metabolic changes among different yeasts. Saccharomyces cerevisiae BY4742 and CEN.PK2-1C strains are originated from different yeast strains and are commonly used as model organisms and chassis cells in molecular biology study and synthetic biology-based natural production. Metabolomic analysis showed that the BY4742 strain produced higher levels of phenylalanine, tyrosine than CEN.PK2-1C, while CEN.PK2-1C produced high levels of indoleacetaldehyde, indolepyruvate. Transcriptomic analysis showed that the two strains showed large differences in the glycolysis pathway and pyruvate metabolism pathway. CEN.PK2-1C had greater glycolysis flux than BY4742, whereas BY4742 has greater flux in the pathway of pyruvate metabolism to produce fumarate. These findings provide a basis knowledge of the metabolomic and transcriptomic differences between BY4742 and CEN.PK2-1C strains, and also provide preliminary information for strain selection for molecular biology study and synthetic biology-based natural product production.

Application of RET Approach for Ratiometric Response Enhancement of ICT Fluorescent Hg2+ Probe based on Crown-containing Styrylpyridinium Dye.

Styrylpyridinium dye bearing azadithia-15-crown-5 ether receptor group SP and 4-alkoxy-1,8-naphthalimide fluorophore were linked using copper-catalyzed azide-alkyne cycloaddition click reaction to afford dyad compound NI-SP. Chemosensor NI-SP exhibited selective ratiometric fluorescent response to the presence of Hg2+ in aqueous solution due to the interplay between resonance energy transfer (RET) and intramolecular charge transfer (ICT) processes occurred upon excitation. The observed switching of the ratio of emission intensities in the blue and red channels R was higher than in the case of monochromophoric styrylpyridine derivative SP showing ratiometric response based on ICT mechanism only. Biological studies revealed that NI-SP penetrates into human lung adenocarcinoma A549 cells and accumulates in cytoplasm and lysosomes. When cells were pre-incubated with mercury (II) perchlorate, the ratio R was increased 2.6 times, which enables detection of intracellular Hg2+ ions and their quantitative analysis in the 0.7-6.0 μM concentration range.