NEW ORIGINAL DRUG ROSEOFUNGIN-AS, OINTMENT 2%

В статье приводятся сведения о разработке нового отечественного противогрибкового препарата «Розеофунгин-АС, мазь 2%» для наружного применения на основе оригинального природного полиенового антибиотика розеофунгина. Приводятся данные о продуценте антибиотика, процессе его биосинтеза и получения, его физико-химических свойствах и химической структуре, рассматриваются его антифунгальные и антивирусные свойства, механизм его действия, а также основные этапы разработки противогрибкового препарата - доклинические и I, II и III фазы клинических исследований. This paper provides the information on the development of new domestic antifungal drug Roseofungin-AS, ointment 2% for external use based on the original natural polyene antibiotic roseofungin. Data on the antibiotic producer, the process of its biosynthesis and production, its physicochemical properties and chemical structure are presented, its antifungal and antiviral properties, the mechanism of action as well as the main stages of the antifungal drug development including preclinical and phase I, II, III clinical trials are discussed.

Can Channel-Forming Antibiotics In Complex with Carriers Provide Enhanced Muscle Activity?

The presented review and experimental work provides the data regarding the selective permeability of lipid and cell membranes for ions and organic compounds under the influence of channel-forming polyene compounds with a known molecule structure. It has been shown that the polyene antibiotic levorin А2 with an aromatic structure affects a number of physicochemical parameters of lipid membranes. It was established that the permeability of lipid and cellular membranes for monovalent cations, as well as for monosugar and other neutral molecules increases under the influence of a levorin of А2. The biological activity of levorin А2 and the rate of delivery of molecules to the membranes depend on the surface tension and substrate environment of the membranes. It has been shown that in combination with levorin, dimethyl sulfoxide, and citral, the surface tension of the aqueous solutions surrounding the membrane decreases by half. Comparative data on levorin А2 effects on lipid membranes and muscle cell membranes are presented. It is assumed that levorin А2, being a channel-forming compound, can induce the formation of additional permeability channels in the membranes of muscle cells and, with intense muscle activity, enhance the transfer of cation and energy-dependent substrates through the membranes.

Eliciting the silent lucensomycin biosynthetic pathway in Streptomyces cyanogenus S136 via manipulation of the global regulatory gene adpA

Actinobacteria are among the most prolific sources of medically and agriculturally important compounds, derived from their biosynthetic gene clusters (BGCs) for specialized (secondary) pathways of metabolism. Genomics witnesses that the majority of actinobacterial BGCs are silent, most likely due to their low or zero transcription. Much effort is put into the search for approaches towards activation of silent BGCs, as this is believed to revitalize the discovery of novel natural products. We hypothesized that the global transcriptional factor AdpA, due to its highly degenerate operator sequence, could be used to upregulate the expression of silent BGCs. Using Streptomyces cyanogenus S136 as a test case, we showed that plasmids expressing either full-length adpA or its DNA-binding domain led to significant changes in the metabolome. These were evident as changes in the accumulation of colored compounds, bioactivity, as well as the emergence of a new pattern of secondary metabolites as revealed by HPLC-ESI-mass spectrometry. We further focused on the most abundant secondary metabolite and identified it as the polyene antibiotic lucensomycin. Finally, we uncovered the entire gene cluster for lucensomycin biosynthesis (lcm), that remained elusive for five decades until now, and outlined an evidence-based scenario for its adpA-mediated activation.

Antifungal macrocycle antibiotic amphotericin B — its present and future. Multidisciplinary perspective for the use in the medical practice

This review is devoted to a broad analysis of the results of studies of the effect of macrocyclic antifungal polyene antibiotic amphotericin B on cell membranes. A multi-prolonged study of polyenes showed that some of them can have not only antifungal, but also antiviral and antitumor action. Fungal pathology develops especially quickly and in this case leads to invasive aspergillosis, which contributes to the complication of coronavirus infection in the lungs and even secondary infection with invasive aspergillosis in the context of a global pandemic. The treatment of an invasive form of bronchopulmonary aspergillosis is directly related to the immunomodulatory and immunostimulating properties of the macrocyclic polyene drug amphotericin B. The article presents experimental data on the study of the biological activity and membrane properties of amphotericin B and the effect of its chemically modified derivatives, as well as liposomal forms of amphotericin B on viral, bacterial and fungal infections. The mechanism of action of amphotericin B and its analogues is based on their interaction with cellular and lipid membranes, by forming ion channels of molecular size in them. The importance of these studies is that polyenes are sensitive to membranes that contain sterols of a certain structure. The analysis showed that pathogenic fungal cells containing ergosterol were 10-100 times more sensitive to polyene antibiotics than host cell membranes containing cholesterol. The high sterol selectivity of the action of polyenes opens up broad prospects for the use of polyene antifungal drugs in practical medicine and pharmacology in the treatment of invasive mycoses and the prevention of atherosclerosis. In this connection, it should be noted that polyene antibiotics are the main tool in the study of the biochemical mechanism of changes in the permeability of cell membranes for energy-dependent substrates. Chemical and genetic engineering transformation of the structure of polyene antibiotic molecules opens up prospects for the identification and creation of new biologically active forms of the antibiotic that have a high selectivity of action in the treatment of pathogenic infections.

A Hierarchical Network of Four Regulatory Genes Controlling Production of the Polyene Antibiotic Candicidin in Streptomyces sp. Strain FR-008

ABSTRACT The four regulatory genes fscR1 to fscR4 in Streptomyces sp. strain FR-008 form a genetic arrangement that is widely distributed in macrolide-producing bacteria. Our previous work has demonstrated that fscR1 and fscR4 are critical for production of the polyene antibiotic candicidin. In this study, we further characterized the roles of the other two regulatory genes, fscR2 and fscR3, focusing on the relationship between these four regulatory genes. Disruption of a single or multiple regulatory genes did not affect bacterial growth, but transcription of genes in the candicidin biosynthetic gene cluster decreased, and candicidin production was abolished, indicating a critical role for each of the four regulatory genes, including fscR2 and fscR3, in candicidin biosynthesis. We found that fscR1 to fscR4, although differentially expressed throughout the growth phase, displayed similar temporal expression patterns, with an abrupt increase in the early exponential phase, coincident with initial detection of antibiotic production in the same phase. Our data suggest that the four regulatory genes fscR1 to fscR4 have various degrees of control over structural genes in the biosynthetic cluster under the conditions examined. Extensive transcriptional analysis indicated that complex regulation exists between these four regulatory genes, forming a regulatory network, with fscR1 and fscR4 functioning at a lower level. Comprehensive cross-complementation analysis indicates that functional complementation is restricted among the four regulators and unidirectional, with fscR1 complementing the loss of fscR3 or -4 and fscR4 complementing loss of fscR2. Our study provides more insights into the roles of, and the regulatory network formed by, these four regulatory genes controlling production of an important pharmaceutical compound. IMPORTANCE The regulation of antibiotic biosynthesis by Streptomyces species is complex, especially for biosynthetic gene clusters with multiple regulatory genes. The biosynthetic gene cluster for the polyene antibiotic candicidin contains four consecutive regulatory genes, which encode regulatory proteins from different families and which form a subcluster within the larger biosynthetic gene cluster in Streptomyces sp. FR-008. Syntenic arrangements of these regulatory genes are widely distributed in polyene gene clusters, such as the amphotericin and nystatin gene clusters, suggesting a conserved regulatory mechanism controlling production of these clinically important medicines. However, the relationships between these multiple regulatory genes are unknown. In this study, we determined that each of these four regulatory genes is critical for candicidin production. Additionally, using transcriptional analyses, bioassays, high-performance liquid chromatography (HPLC) analysis, and genetic cross-complementation, we showed that FscR1 to FscR4 comprise a hierarchical regulatory network that controls candicidin production and is likely representative of how expression of other polyene biosynthetic gene clusters is controlled.

A natural solution to photoprotection and isolation of the potent polyene antibiotic, marinomycin A

Perfect partners for photoprotection: orally ingestible sporopollenin confers striking photoprotection to the powerful, polyene antibiotic, marinomycin A, as well as enabling its selective extraction.

Heterologous Expression of Full-Length Lanosterol 14α-Demethylases of Prominent Fungal PathogensCandida albicansandCandida glabrataProvides Tools for Antifungal Discovery

ABSTRACTTargeting lanosterol 14α-demethylase (LDM) with azole drugs provides prophylaxis and treatments for superficial and disseminated fungal infections, but cure rates are modest for immunocompromised patients and individuals with comorbidities. The efficacy of azole drugs has also been reduced due to the emergence of drug-resistant fungal pathogens. We have addressed these problems by expressing inSaccharomyces cerevisiaefunctional, hexahistidine-tagged, full-lengthCandida albicansLDM (CaLDM6×His) andCandida glabrataLDM (CgLDM6×His) for drug discovery purposes and determining their X-ray crystal structures. Compared withS. cerevisiaeoverexpressing LDM6×His (ScLDM6×His), the reduced susceptibility of CgLDM6×His to all azole drugs tested correlated with its level of overexpression. In contrast, the reduced susceptibility to short-tailed (fluconazole and voriconazole) but not medium-tailed (VT-1161) or long-tailed azoles (itraconazole and posaconazole) indicates CaLDM6×His works best when coexpressed with its cognate NADPH-cytochrome P450 reductase (CaNcp1A) rather than the host reductase (ScNcp1). Overexpression of LDM or Ncp1 modified the ergosterol content of yeast and affected growth inhibition by the polyene antibiotic amphotericin B. Affinity-purified recombinantCandidaLDMs bind carbon monoxide and show tight type II binding of a range of azole drugs, including itraconazole, posaconazole, fluconazole, and voriconazole. This study provides a practical basis for the phenotype-, biochemistry-, and structure-directed discovery of novel antifungals that target LDMs of fungal pathogens.