Unraveling Caspofungin Resistance in Cryptococcus neoformans

Design of a cryptococcus neoformans vaccine by subtractive proteomics combined with immunoinformatics

The emergence of Cryptococcus neoformans has posed an undeniable burden to many regions worldwide, with its strains mainly entering the lungs through the respiratory tract and spreading throughout the body. Limitations of drug regimens, such as high costs and limited options, have directed our attention toward the promising field of vaccine development. In this study, the subtractive proteomics approach was employed to select target proteins from databases that can accurately cover serotypes A and D of the Cryptococcus neoformans. Further, two multi-epitope vaccines consisting of T and B cell epitopes were demonstrated that they have good structural stability and could bind with immune receptor to induce desired immune responses in silico. After further evaluation, these vaccines show the potential for large-scale production and applicability to the majority of the population of the world. In summary, these two vaccines have been theoretically proven to combat Cryptococcus neoformans infections, awaiting further experimental validation of their actual protective effects.

Development of a yeast cell based method for efficient screening of high yield tacrolimus production strain

Tacrolimus (FK506) is a widely used and clinically important immunosuppressant drug that can be produced by fermentation of Streptomyces tsukubaensis. The industrial strains are typically obtained through multiple rounds of mutagenesis and screening, a labor-intensive process. We have established an efficient yeast cell based screening method for the evolutionary process of high-FK506-yielding strain. The S. tsukubaensis strains of different FK506 yields were tested for zone of growth inhibition of the wild type and calcineurin mutant (cnb1∆) yeast strains. We found that different FK506 yields correspond well to altered yeast growth inhibitions. Based on the combinational inhibition effects of FK506 with different antifungals that have been frequently reported, we also tested the zone of inhibition by addition of fluconazole, amphotericin B and caspofungin to the medium. In the end, for the best screening performance, we systemically evaluated the strategy when different yeast strains and different antifungals were used according to the clarity, size, and divergence of the inhibition circles. Using different yeast strains and antifungals, we successfully broadened the screening spectrum. An efficient high-FK506-yield S. tsukubaensis screening method has been established and optimized.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03870-y.

Red-shifted and pH-responsive imidazole-based azo dyes with potent antimicrobial activity

A novel route is described to obtain 2-aminoimidazole azo dyes with a unique substituent pattern in the heteroaryl unit that provides halochromic properties, exhibiting vibrant colours that change from magenta to deep blue. Potent antimicrobial properties against infectious yeasts were demonstrated. No cytotoxicity was detected for concentrations lower than 16 μg mL^-1.

Nanotechnology-Based Approaches for Voriconazole Delivery Applied to Invasive Fungal Infections

Invasive fungal infections increase mortality and morbidity rates worldwide. The treatment of these infections is still limited due to the low bioavailability and toxicity, requiring therapeutic monitoring, especially in the most severe cases. Voriconazole is an azole widely used to treat invasive aspergillosis, other hyaline molds, many dematiaceous molds, Candida spp., including those resistant to fluconazole, and for infections caused by endemic mycoses, in addition to those that occur in the central nervous system. However, despite its broad activity, using voriconazole has limitations related to its non-linear pharmacokinetics, leading to supratherapeutic doses and increased toxicity according to individual polymorphisms during its metabolism. In this sense, nanotechnology-based drug delivery systems have successfully improved the physicochemical and biological aspects of different classes of drugs, including antifungals. In this review, we highlighted recent work that has applied nanotechnology to deliver voriconazole. These systems allowed increased permeation and deposition of voriconazole in target tissues from a controlled and sustained release in different routes of administration such as ocular, pulmonary, oral, topical, and parenteral. Thus, nanotechnology application aiming to delivery voriconazole becomes a more effective and safer therapeutic alternative in the treatment of fungal infections.