scholarly journals Targeting the Homoserine Dehydrogenase of Paracoccidioides Species for Treatment of Systemic Fungal Infections

2017 ◽  
Vol 61 (9) ◽  
Author(s):  
Mariane C. Bagatin ◽  
Arethusa L. Pimentel ◽  
Débora C. Biavatti ◽  
Ernani A. Basso ◽  
Erika S. Kioshima ◽  
...  
Keyword(s):  
Tertiary Structure ◽  
Fungal Infections ◽  
Paracoccidioides Brasiliensis ◽  
Pathogenic Fungi ◽  
Dynamics Simulation ◽  
Homoserine Dehydrogenase ◽  
Content Type ◽  
Zinc Database ◽  
Etiological Agents

ABSTRACT This work evaluated new potential inhibitors of the enzyme homoserine dehydrogenase (HSD) of Paracoccidioides brasiliensis, one of the etiological agents of paracoccidioidomycosis. The tertiary structure of the protein bonded to the analogue NAD, and l-homoserine was modeled by homology. The model with the best output was subjected to gradient minimization, redocking, and molecular dynamics simulation. Virtual screening simulations with 187,841 molecules purchasable from the Zinc database were performed. After the screenings, 14 molecules were selected and analyzed by the use of absorption, distribution, metabolism, excretion, and toxicity criteria, resulting in four compounds for in vitro assays. The molecules HS1 and HS2 were promising, exhibiting MICs of 64 and 32 μg · ml−1, respectively, for the Pb18 isolate of P. brasilensis, 64 μg · ml−1 for two isolates of P. lutzii, and also synergy with itraconazole. The application of these molecules to human-pathogenic fungi confirmed that the HSD enzyme may be used as a target for the development of drugs with specific action against paracoccidioidomycosis; moreover, these compounds may serve as leads in the design of new antifungals.

scholarly journals Comparative Genomics of Pneumocystis Species Suggests the Absence of Genes for myo-Inositol Synthesis and Reliance on Inositol Transport and Metabolism

mBio ◽  
2014 ◽  
Vol 5 (6) ◽  
Author(s):  
Aleksey Porollo ◽  
Thomas M. Sesterhenn ◽  
Margaret S. Collins ◽  
Jeffrey A. Welge ◽  
Melanie T. Cushion
Keyword(s):  
Fission Yeast ◽  
Fungal Infections ◽  
Inositol Phosphate ◽  
Pathogenic Fungi ◽  
Phosphate Metabolism ◽  
Transport Pathways ◽  
Content Type ◽  
Inositol Phosphate Metabolism ◽  
Genes Encoding

ABSTRACTIn the context of deciphering the metabolic strategies of the obligate pathogenic fungi in the genusPneumocystis, the genomes of three species (P. carinii,P. murina, andP. jirovecii) were compared among themselves and with the free-living, phylogenetically related fission yeast (Schizosaccharomyces pombe). The underrepresentation of amino acid metabolism pathways compared to those inS. pombe, as well as the incomplete steroid biosynthesis pathway, were confirmed forP. cariniiandP. jiroveciiand extended toP. murina. All threePneumocystisspecies showed overrepresentation of the inositol phosphate metabolism pathway compared to that in the fission yeast. In addition to those known inS. pombe, four genes, encoding inositol-polyphosphate multikinase (EC 2.7.1.151), inositol-pentakisphosphate 2-kinase (EC 2.7.1.158), phosphoinositide 5-phosphatase (EC 3.1.3.36), and inositol-1,4-bisphosphate 1-phosphatase (EC 3.1.3.57), were identified in the two rodentPneumocystisgenomes,P. cariniiandP. murina. TheP. jiroveciigenome appeared to contain three of these genes but lacked phosphoinositide 5-phosphatase. Notably, two genes encoding enzymes essential formyo-inositol synthesis, inositol-1-phosphate synthase (INO1) and inositol monophosphatase (INM1), were absent from all three genomes, suggesting thatPneumocystisspecies are inositol auxotrophs. In keeping with the need to acquire exogenous inositol, two genes with products homologous to fungal inositol transporters, ITR1 and ITR2, were identified inP. cariniiandP. murina, whileP. jiroveciicontained only the ITR1 homolog. The ITR and inositol metabolism genes inP. murinaandP. cariniiwere expressed during fulminant infection as determined by reverse transcriptase real-time PCR of cDNA from infected lung tissue. Supplementation ofin vitroculture with inositol yielded significant improvement of the viability ofP. cariniifor days 7 through 14.IMPORTANCEMicrobes in the genusPneumocystisare obligate pathogenic fungi that reside in mammalian lungs and causePneumocystispneumonia in hosts with weakened immune systems. These fungal infections are not responsive to standard antifungal therapy. A long-termin vitroculture system is not available for these fungi, impeding the study of their biology and genetics and new drug development. Given that all genomes of thePneumocystisspecies analyzed lack the genes for inositol synthesis and contain inositol transporters,Pneumocystisfungi, likeS. pombe, appear to be inositol auxotrophs. Inositol is important for the pathogenesis, virulence, and mating processes inCandida albicansandCryptococcus neoformans, suggesting similar importance within thePneumocystisspecies as well. This is the first report to (i) characterize genes in the inositol phosphate metabolism and transport pathways inPneumocystisspecies and (ii) identify inositol as a supplement that improved the viability ofP. cariniiinin vitroculture.

Evaluation of the in vitro and in vivo dimorphism ofSporothrix schenckii,Blastomyces dermatitidis, andParacoccidioides brasiliensisisolates after preservation in mineral oil

2004 ◽  
Vol 50 (6) ◽  
pp. 445-449 ◽  
Author(s):  
Renata Ferretti de Lima ◽  
Marcelly Maria dos Santos Brito ◽  
Guido Manoel Vidal Schäffer ◽  
Osana Cunha de Lima ◽  
Cintia de Moraes Borba
Keyword(s):  
Fungal Infections ◽  
Paracoccidioides Brasiliensis ◽  
Sporothrix Schenckii ◽  
Brain Heart Infusion ◽  
Morphological Differentiation ◽  
Pathogenic Fungi ◽  
Mineral Oil ◽  
Blastomyces Dermatitidis

Morphological differentiation has commanded attention for its putative impact on the pathogenesis of invasive fungal infections. We evaluated in vitro and in vivo the dimorphism from mycelial to yeast-phase of Sporothrix schenckii, Blastomyces dermatitidis and Paracoccidioides brasiliensis isolates, two strains for each species, preserved in mineral oil. S. schenckii strains showed typical micromorphology at 25 °C but one strain was unable to complete the dimorphic process in vitro. After in vivo passage through mice the strains had the ability to turn into yeast-like cells and to form colonies on brain-heart infusion medium at 36 °C. B. dermatitidis strains grew as dirty white to brownish membranous colonies at 25 °C and their micromorphology showed thin filaments with single hyaline conidia. At 36 °C the colonies did not differ from those grown at 25 °C, but produced a transitional micromorphology. P. brasiliensis strains grew as cream-colored cerebriform colonies at 25 °C showing a transitional morphology. B. dermatitidis and P. brasiliensis strains did not turn into yeast-like cells in vivo. The present results demonstrate that B. dermatitidis and P. brasiliensis strains were unable to complete the dimorphic process even after in vivo passage, in contrast to the S. schenckii strain.Key words: pathogenic fungi, in vitro storage, in vivo passage, morphogenesis.

scholarly journals Nanoemulsion as an Effective Treatment against Human-Pathogenic Fungi

mSphere ◽  
2019 ◽  
Vol 4 (6) ◽  
Author(s):  
Alexis Garcia ◽  
Yong Yi Fan ◽  
Sandeep Vellanki ◽  
Eun Young Huh ◽  
DiFernando Vanegas ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Fungal Infections ◽  
Pathogenic Fungi ◽  
Antifungal Drugs ◽  
Solid Organ ◽  
Therapeutic Approaches ◽  
Content Type ◽  
New Therapeutic Approaches ◽  
Development Of Resistance

ABSTRACT Infections triggered by pathogenic fungi cause a serious threat to the public health care system. In particular, an increase of antifungal drug-resistant fungi has resulted in difficulty in treatment. A limited variety of antifungal drugs available to treat patients has left us in a situation where we need to develop new therapeutic approaches that are less prone to development of resistance by pathogenic fungi. In this study, we demonstrate the efficacy of the nanoemulsion NB-201, which utilizes the surfactant benzalkonium chloride, against human-pathogenic fungi. We found that NB-201 exhibited in vitro activity against Candida albicans, including both planktonic growth and biofilms. Furthermore, treatments with NB-201 significantly reduced the fungal burden at the infection site and presented an enhanced healing process after subcutaneous infections by multidrug-resistant C. albicans in a murine host system. NB-201 also exhibited in vitro growth inhibition activity against other fungal pathogens, including Cryptococcus spp., Aspergillus fumigatus, and Mucorales. Due to the nature of the activity of this nanoemulsion, there is a minimized chance of drug resistance developing, presenting a novel treatment to control fungal wound or skin infections. IMPORTANCE Advances in medicine have resulted in the discovery and implementation of treatments for human disease. While these recent advances have been beneficial, procedures such as solid-organ transplants and cancer treatments have left many patients in an immunocompromised state. Furthermore, the emergence of immunocompromising diseases such as HIV/AIDS or other immunosuppressive medical conditions have opened an opportunity for fungal infections to afflict patients globally. The development of drug resistance in human-pathogenic fungi and the limited array of antifungal drugs has left us in a scenario where we need to develop new therapeutic approaches to treat fungal infections that are less prone to the development of resistance by pathogenic fungi. The significance of our work lies in utilizing a novel nanoemulsion formulation to treat topical fungal infections while minimizing risks of drug resistance development.

scholarly journals Identification and Predictions Regarding the Biosynthesis Pathway of Polyene Macrolides Produced by Streptomyces roseoflavus Men-myco-93-63

2021 ◽  
Vol 87 (10) ◽  
Author(s):  
Xing Han ◽  
Jiao Wang ◽  
Lianna Liu ◽  
Fengying Shen ◽  
Qingfang Meng ◽  
...  
Keyword(s):  
Fermentation Broth ◽  
Pathogenic Fungi ◽  
Biosynthetic Gene Cluster ◽  
Inhibitory Effect ◽  
Plant Diseases ◽  
Active Metabolites ◽  
Content Type ◽  
Polyene Macrolides ◽  
Alternative Agent

ABSTRACT A group of polyene macrolides mainly composed of two constituents was isolated from the fermentation broth of Streptomyces roseoflavus Men-myco-93-63, which was isolated from soil where potato scabs were repressed naturally. One of these macrolides was roflamycoin, which was first reported in 1968, and the other was a novel compound named Men-myco-A, which had one methylene unit more than roflamycoin. Together, they were designated RM. This group of antibiotics exhibited broad-spectrum antifungal activities in vitro against 17 plant-pathogenic fungi, with 50% effective concentrations (EC50) of 2.05 to 7.09 μg/ml and 90% effective concentrations (EC90) of 4.32 to 54.45 μg/ml, which indicates their potential use in plant disease control. Furthermore, their biosynthetic gene cluster was identified, and the associated biosynthetic assembly line was proposed based on a module and domain analysis of polyketide synthases (PKSs), supported by findings from gene inactivation experiments. IMPORTANCE Streptomyces roseoflavus Men-myco-93-63 is a biocontrol strain that has been studied in our laboratory for many years and exhibits a good inhibitory effect in many crop diseases. Therefore, the identification of antimicrobial metabolites is necessary and our main objective. In this work, chemical, bioinformatic, and molecular biological methods were combined to identify the structures and biosynthesis of the active metabolites. This work provides a new alternative agent for the biological control of plant diseases and is helpful for improving both the properties and yield of the antibiotics via genetic engineering.

scholarly journals Acylhydrazones as Antifungal Agents Targeting the Synthesis of Fungal Sphingolipids

2018 ◽  
Vol 62 (5) ◽  
Author(s):  
Cristina Lazzarini ◽  
Krupanandan Haranahalli ◽  
Robert Rieger ◽  
Hari Krishna Ananthula ◽  
Pankaj B. Desai ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Antifungal Agents ◽  
Fungal Infections ◽  
Antifungal Drugs ◽  
Fungal Resistance ◽  
Content Type ◽  
Highly Active ◽  
Pharmacokinetic Properties ◽  
Pass Through

ABSTRACTThe incidence of invasive fungal infections has risen dramatically in recent decades. Current antifungal drugs are either toxic, likely to interact with other drugs, have a narrow spectrum of activity, or induce fungal resistance. Hence, there is a great need for new antifungals, possibly with novel mechanisms of action. Previously our group reported an acylhydrazone called BHBM that targeted the sphingolipid pathway and showed strong antifungal activity against several fungi. In this study, we screened 19 derivatives of BHBM. Three out of 19 derivatives were highly active againstCryptococcus neoformansin vitroand had low toxicity in mammalian cells. In particular, one of them, called D13, had a high selectivity index and showed better activity in an animal model of cryptococcosis, candidiasis, and pulmonary aspergillosis. D13 also displayed suitable pharmacokinetic properties and was able to pass through the blood-brain barrier. These results suggest that acylhydrazones are promising molecules for the research and development of new antifungal agents.

scholarly journals In Vitro Activity of a Novel Antifungal Compound, MYC-053, against Clinically Significant Antifungal-Resistant Strains of Candida glabrata, Candida auris, Cryptococcus neoformans, and Pneumocystis spp.

2019 ◽  
Vol 63 (4) ◽  
Author(s):  
G. Tetz ◽  
M. Collins ◽  
D. Vikina ◽  
V. Tetz
Keyword(s):  
Cryptococcus Neoformans ◽  
Candida Glabrata ◽  
Fungal Infections ◽  
Antifungal Compound ◽  
Candida Auris ◽  
Content Type ◽  
Treatment And Prevention ◽  
Resistant Strains ◽  
Clinically Significant

ABSTRACT An urgent need exists for new antifungal compounds to treat fungal infections in immunocompromised patients. The aim of the current study was to investigate the potency of a novel antifungal compound, MYC-053, against the emerging yeast and yeast-like pathogens Candida glabrata, Candida auris, Cryptococcus neoformans, and Pneumocystis species. MYC-053 was equally effective against the susceptible control strains, clinical isolates, and resistant strains, with MICs of 0.125 to 4.0 μg/ml. Notably, unlike other antifungals such as azoles, polyenes, and echinocandins, MYC-053 was effective against Pneumocystis isolates, therefore being the only synthetic antifungal that may potentially be used against Pneumocystis spp., Candida spp., and Cryptococcus spp. MYC-053 was highly effective against preformed 48-h-old C. glabrata and C. neoformans biofilms, with minimal biofilm eradication concentrations equal to 1 to 4 times the MIC. Together, these data indicated that MYC-053 may be developed into a promising antifungal agent for the treatment and prevention of invasive fungal infections caused by yeasts and yeast-like fungi.

scholarly journals New Triazole NT-a9 Has Potent Antifungal Efficacy against Cryptococcus neoformans In Vitro and In Vivo

2019 ◽  
Vol 64 (2) ◽  
Author(s):  
Ren-Yi Lu ◽  
Ting-Jun-Hong Ni ◽  
Jing Wu ◽  
Lan Yan ◽  
Quan-Zhen Lv ◽  
...  
Keyword(s):  
Cryptococcus Neoformans ◽  
Amphotericin B ◽  
Pathogenic Fungi ◽  
Control Group ◽  
Survival Times ◽  
Content Type ◽  
Fungal Burden ◽  
Wide Range

ABSTRACT In the past decades, the incidence of cryptococcosis has increased dramatically, which poses a new threat to human health. However, only a few drugs are available for the treatment of cryptococcosis. Here, we described a leading compound, NT-a9, an analogue of isavuconazole, that showed strong antifungal activities in vitro and in vivo. NT-a9 showed a wide range of activities against several pathogenic fungi in vitro, including Cryptococcus neoformans, Cryptococcus gattii, Candida albicans, Candida krusei, Candida tropicalis, Candida glabrata, and Candida parapsilosis, with MICs ranging from 0.002 to 1 μg/ml. In particular, NT-a9 exhibited excellent efficacy against C. neoformans, with a MIC as low as 0.002 μg/ml. NT-a9 treatment resulted in changes in the sterol contents in C. neoformans, similarly to fluconazole. In addition, NT-a9 possessed relatively low cytotoxicity and a high selectivity index. The in vivo efficacy of NT-a9 was assessed using a murine disseminated-cryptococcosis model. Mice were infected intravenously with 1.8 × 106 CFU of C. neoformans strain H99. In the survival study, NT-a9 significantly prolonged the survival times of mice compared with the survival times of the control group or the isavuconazole-, fluconazole-, or amphotericin B-treated groups. Of note, 4 and 8 mg/kg of body weight of NT-a9 rescued all the mice, with a survival rate of 100%. In the fungal-burden study, NT-a9 also significantly reduced the fungal burdens in brains and lungs, while fluconazole and amphotericin B only reduced the fungal burden in lungs. Taken together, these data suggested that NT-a9 is a promising antifungal candidate for the treatment of cryptococcosis infection.

scholarly journals Enhancing the Promiscuous Phosphotriesterase Activity of a Thermostable Lactonase (GkaP) for the Efficient Degradation of Organophosphate Pesticides

2012 ◽  
Vol 78 (18) ◽  
pp. 6647-6655 ◽  
Author(s):  
Yu Zhang ◽  
Jiao An ◽  
Wei Ye ◽  
Guangyu Yang ◽  
Zhi-Gang Qian ◽  
...  
Keyword(s):  
Catalytic Efficiency ◽  
Dynamics Simulation ◽  
Saturation Mutagenesis ◽  
Divergent Evolution ◽  
Laboratory Evolution ◽  
Content Type ◽  
Hydrolytic Activities ◽  
Geobacillus Kaustophilus ◽  
Amidohydrolase Superfamily

ABSTRACTThe phosphotriesterase-like lactonase (PLL) enzymes in the amidohydrolase superfamily hydrolyze various lactones and exhibit latent phosphotriesterase activities. These enzymes serve as attractive templates forin vitroevolution of neurotoxic organophosphates (OPs) with hydrolytic capabilities that can be used as bioremediation tools. Here, a thermostable PLL fromGeobacillus kaustophilusHTA426 (GkaP) was targeted for joint laboratory evolution with the aim of enhancing its catalytic efficiency against OP pesticides. By a combination of site saturation mutagenesis and whole-gene error-prone PCR approaches, several improved variants were isolated. The most active variant, 26A8C, accumulated eight amino acid substitutions and demonstrated a 232-fold improvement over the wild-type enzyme in reactivity (kcat/Km) for the OP pesticideethyl-paraoxon. Concomitantly, this variant showed a 767-fold decrease in lactonase activity with δ-decanolactone, imparting a specificity switch of 1.8 × 105-fold. 26A8C also exhibited high hydrolytic activities (19- to 497-fold) for several OP pesticides, including parathion, diazinon, and chlorpyrifos. Analysis of the mutagenesis sites on the GkaP structure revealed that most mutations are located in loop 8, which determines substrate specificity in the amidohydrolase superfamily. Molecular dynamics simulation shed light on why 26A8C lost its native lactonase activity and improved the promiscuous phosphotriesterase activity. These results permit us to obtain further insights into the divergent evolution of promiscuous enzymes and suggest that laboratory evolution of GkaP may lead to potential biological solutions for the efficient decontamination of neurotoxic OP compounds.

scholarly journals In VitroandIn VivoEvaluation of APX001A/APX001 and Other Gwt1 Inhibitors againstCryptococcus

2018 ◽  
Vol 62 (8) ◽  
Author(s):  
Karen Joy Shaw ◽  
Wiley A. Schell ◽  
Jonathan Covel ◽  
Gisele Duboc ◽  
C. Giamberardino ◽  
...  
Keyword(s):  
Brain Tissue ◽  
Lung Tissue ◽  
Fungal Infections ◽  
Treatment Options ◽  
Content Type ◽  
Fungal Burden ◽  
Geographical Regions ◽  
Current Therapies

ABSTRACTCryptococcal meningitis (CM), caused primarily byCryptococcus neoformans, is uniformly fatal if not treated. Treatment options are limited, especially in resource-poor geographical regions, and mortality rates remain high despite current therapies. Here we evaluated thein vitroandin vivoactivity of several compounds, including APX001A and its prodrug, APX001, currently in clinical development for the treatment of invasive fungal infections. These compounds target the conserved Gwt1 enzyme that is required for the localization of glycosylphosphatidylinositol (GPI)-anchored cell wall mannoproteins in fungi. The Gwt1 inhibitors had low MIC values, ranging from 0.004 μg/ml to 0.5 μg/ml, against bothC. neoformansandC. gattii. APX001A and APX2020 demonstratedin vitrosynergy with fluconazole (fractional inhibitory concentration index, 0.37 for both). In a CM model, APX001 and fluconazole each alone reduced the fungal burden in brain tissue (0.78 and 1.04 log10CFU/g, respectively), whereas the combination resulted in a reduction of 3.52 log10CFU/g brain tissue. Efficacy, as measured by a reduction in the brain and lung tissue fungal burden, was also observed for another Gwt1 inhibitor prodrug, APX2096, where dose-dependent reductions in the fungal burden ranged from 5.91 to 1.79 log10CFU/g lung tissue and from 7.00 and 0.92 log10CFU/g brain tissue, representing the nearly complete or complete sterilization of lung and brain tissue at the higher doses. These data support the further clinical evaluation of this new class of antifungal agents for the treatment of CM.

scholarly journals Echinocandins for the Treatment of Invasive Aspergillosis: from Laboratory to Bedside

2019 ◽  
Vol 63 (8) ◽  
Author(s):  
Marion Aruanno ◽  
Emmanouil Glampedakis ◽  
Frédéric Lamoth
Keyword(s):  
Invasive Aspergillosis ◽  
Fungal Infections ◽  
Heat Shock Protein 90 ◽  
Hyphal Growth ◽  
Content Type ◽  
Complex Interactions ◽  
Drug Classes ◽  
Paradoxical Growth ◽  
Glucan Synthesis

ABSTRACT Echinocandins (caspofungin, micafungin, anidulafungin), targeting β-1,3-glucan synthesis of the cell wall, represent one of the three currently available antifungal drug classes for the treatment of invasive fungal infections. Despite their limited antifungal activity against Aspergillus spp., echinocandins are considered an alternative option for the treatment of invasive aspergillosis (IA). This drug class exhibits several advantages, such as excellent tolerability and its potential for synergistic interactions with some other antifungals. The objective of this review is to discuss the in vitro and clinical efficacy of echinocandins against Aspergillus spp., considering the complex interactions between the drug, the mold, and the host. The antifungal effect of echinocandins is not limited to direct inhibition of hyphal growth but also induces an immunomodulatory effect on the host’s response. Moreover, Aspergillus spp. have developed important adaptive mechanisms of tolerance to survive and overcome the action of echinocandins, such as paradoxical growth at increased concentrations. This stress response can be abolished by several compounds that potentiate the activity of echinocandins, such as drugs targeting the heat shock protein 90 (Hsp90)-calcineurin axis, opening perspectives for adjuvant therapies. Finally, the present and future places of echinocandins as prophylaxis, monotherapy, or combination therapy of IA are discussed in view of the emergence of pan-azole resistance among Aspergillus fumigatus isolates, the occurrence of breakthrough IA, and the advent of new long-lasting echinocandins (rezafungin) or other β-1,3-glucan synthase inhibitors (ibrexafungerp).

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