Candida albicans Adaptation on Simulated Human Body Fluids under Different pH

Isobavachalcone exhibits antifungal and antibiofilm effects against C. albicans by disrupting cell wall/membrane integrity and inducing apoptosis and autophagy

Isobavachalcone (IBC) is a natural flavonoid with multiple pharmacological properties. This study aimed to evaluate the efficacy of IBC against planktonic growth and biofilms of Candida albicans (C. albicans) and the mechanisms underlying its antifungal action. The cell membrane integrity, cell metabolic viability, and cell morphology of C. albicans treated with IBC were evaluated using CLSM and FESEM analyses. Crystal violet staining, CLSM, and FESEM were used to assess the inhibition of biofilm formation, as well as dispersal and killing effects of IBC on mature biofilms. RNA-seq combined with apoptosis and autophagy assays was used to examine the mechanisms underlying the antifungal action of IBC. IBC exhibited excellent antifungal activity with 8 μg/mL of MIC for C. albicans. IBC disrupted the cell membrane integrity, and inhibited biofilm formation. IBC dispersed mature biofilms and damaged biofilm cells of C. albicans at 32 μg/mL. Moreover, IBC induced apoptosis and autophagy-associated cell death of C. albicans. The RNA-seq analysis revealed upregulation or downregulation of key genes involved in cell wall synthesis (Wsc1 and Fks1), ergosterol biosynthesis (Erg3, and Erg11), apoptisis (Hsp90 and Aif1), as well as autophagy pathways (Atg8, Atg13, and Atg17), and so forth, in response to IBC, as evidenced by the experiment-based phenotypic analysis. These results suggest that IBC inhibits C. albicans growth by disrupting the cell wall/membrane, caused by the altered expression of genes associated with β-1,3-glucan and ergosterol biosynthesis. IBC induces apoptosis and autophagy-associated cell death by upregulating the expression of Hsp90, and altering autophagy-related genes involved in the formation of the Atg1 complex and the pre-autophagosomal structure. Together, our findings provide important insights into the potential multifunctional mechanism of action of IBC.

Characterization of bacteriophage vB_KleM_KB2 possessing high control ability to pathogenic Klebsiella pneumoniae

Klebsiella pneumoniae is a widespread pathogen of several human diseases. The emergence of multidrug-resistant K. pneumoniae makes the treatment of these diseases a significant challenge. The application of bacteriophages is a potential approach for dealing with the emergence of multidrug-resistant pathogenic bacteria. This study isolates a novel bacteriophage vB_KleM_KB2 that infects the multidrug-resistant clinical isolates of K. pneumoniae. The bacteriophage exhibits a short latent period of 10 min, and can effectively lyse the bacterium within 60 min. Notably, the bacteriophage can completely inhibit the growth of the host bacterium at the initial concentration of 107 CFU/mL with a low multiplicity of infection of 0.001, which proves its high lytic activity. Furthermore, the bacteriophage shows high environmental tolerances, which can facilitate the practical application of the bacteriophage. Analysis of the bacteriophage genome shows that the bacteriophage possesses a novel genome sequence and can represent a new bacteriophage genus. Considering the high lytic activity, short latent period, high stability, and novel genetic background, bacteriophage vB_KleM_KB2 enriches the bacteriophage library and provides a new alternative for controlling the diseases caused by multidrug-resistant pathogenic K. pneumoniae.

Compositional analysis and immunomodulatory activity of blue pigment fraction (BPF) from Laba garlic

Laba garlic is a kind of garlic (Allium sativum L.) product and blue pigment fraction (BPF) is the characteristic fraction of Laba garlic. The objective of the study was to isolate BPF from Laba garlic and explore its stability, composition, antioxidant activity, and immunomodulatory activity. The results suggested BPF was unstable under alkaline conditions. Twenty-four constituents including 9 peptides and 10 saponins were detected in BPF by Q Exactive HF LC/MS anlaysis. BPF showed antioxidant activity in a dose-dependent manner. It also showed effective immunomodulatory activity at a concentration of 5 μg/mL at the cellular level and the morphology of RAW 264.7 cells changed to a polygonal and dendritic-like structure. BPF could significantly increase NO production (P < 0.05), and up-regulate the mRNA levels of TNF-α, IL-6, iNOS and NF-κB in the RT-QPCR analysis. The present study systematically analyzed the compositions of BPF for the first time, and the results suggested that BPF might be a potential immunomodulator candidate, which is beneficial for the development and application of garlic products and natural pigments.

Clinical atrophy patterns of filiform papillae of the tongue and their relationship with the serum levels of iron, vitamin B12 and folic acid in patients with systemic diseases

BACKGROUND

The purpose of the study was to evaluate the clinical patterns of atrophy of the filiform papillae (FP) of the tongue and their relationship with the serum levels of iron and vitamin B₁₂ among patients with systemic diseases, in a tertiary care center.

METHODS

A cross-sectional, analytical, research study was designed. A systematic tongue examination was performed to evaluate the presence and clinical patterns of FP atrophy. We collected epidemiologic, clinical, and laboratory data. Statistical analysis included χ² test, Fisher's exact test, Kruskal-Wallis test, and a logistic regression analysis.

RESULTS

A total of 87 patients (83.9% females) were included [median age = 55 (range 20-89) years]. Endocrinopathy (60.9%) was the most frequent comorbidity. We found atrophy of the FP in 90.8% of the patients; the atrophy was mild in 83.5% of the cases, and severe in 16.5%. The most common atrophic patterns were as follows: focalized in 64 (73.6%) cases, "U"-shaped pattern in 60 (69%), and generalized in 30 (34.5%). Geographic tongue and median rhomboid glossitis were observed in 12 (13.8%) and 11 (12.6%) subjects, respectively. Lower titers of serum iron were detected in cases with focal (median = 71 vs. 110 mcg/dl) and generalized (median = 55 vs. 78 mcg/dl) FP atrophy (P = 0.03 and P = 0.009, respectively), than their counterparts. The presence of symptomatology was related to the focal pattern of atrophy (P = 0.038).

CONCLUSIONS

A high frequency of filiform papillary atrophy of the tongue was observed in patients with comorbidities. Some atrophic patterns of the tongue were significantly associated with certain medical conditions.

Antifungal Activity of Mycogenic Silver Nanoparticles on Clinical Yeasts and Phytopathogens

In this study, seven different silver nanoparticles (AgNPs) were obtained using the fungi species from the phylum Ascomycota, Aspergillus tubingensis, Aspergillus spp., Cladosporium pini-ponderosae, Fusarium proliferatum, Epicoccum nigrum, Exserohilum rostratum, and Bionectria ochroleuca, isolated from the Brazilian biodiversity, particularly from the mangrove and Caatinga biomes. The nanoparticles were coded as AgNP-AT, AgNP-Asp, AgNP-CPP, AgNP-FP, AgNP-EN, AgNP-ER, and AgNP-BO and characterized using spectrophotometry (UV-Vis), dynamic light scattering (DLS), zeta potential, transmission electron microcopy (TEM), and Fourier-transform infrared (FTIR) spectroscopy. All the AgNPs presented homogeneous size in the range from 43.4 to 120.6 nm (DLS) and from 21.8 to 35.8 nm (TEM), pH from 4.5 to 7.5, negative charge, and presence of protein coating on their surface. The antifungal activity of the AgNPs was evaluated on clinical strains of Candida albicans, and on the non-albicans species, Candida krusei, Candida glabrata, Candida parapsilosis, Candida tropicalis, and Candida guilliermondii, common in hospital infections, and against the phytopathogens Fusarium oxysporum, Fusarium phaseoli, Fusarium sacchari, Fusarium subglutinans, Fusarium verticillioides, and Curvularia lunata, which are species responsible for serious damage to agriculture production. The AgNPs were effective against the yeasts with MICs ranging from 1.25 to 40 µM and on the phytopathogens with MICs from 4 to 250 µM, indicating the promising possibility of application of these AgNPs as antifungal agents. The results indicated that the physicochemical parameters of the AgNPs, including the functional groups present on their surface, interfered with their antifungal activity. Overall, the results indicate that there is no specificity of the AgNPs for the yeasts or for the phytopathogens, which can be an advantage, increasing the possibility of application in different areas.

Candidacidal and Antibiofilm Activity of PS1-3 Peptide against Drug-Resistant Candida albicans on Contact Lenses

The recent emergence of antibiotic-resistant fungi has accelerated research on novel antifungal agents. In particular, Candida albicans infections are related to biofilm formation on medical devices, such as catheters, stents, and contact lenses, resulting in high morbidity and mortality. In this study, we aimed to elucidate the antifungal and antibiofilm effects of a peptide against drug-resistant C. albicans. α-Helical peptides in which the sequence of KWYK was repeated twice and four times, designated peptide series 1 (PS1)-1 and PS1-3, respectively, were generated, and the candidacidal activities of PS1-1, PS1-3, and fluconazole against drug-resistant C. albicans cells were assessed. The PS1-3 peptide showed higher killing activity than PS1-1 or fluconazole and acted via a membranolytic mechanism. In addition, the PS1-3 peptide exhibited more potent activity than PS1-1 and fluconazole in terms of fungal biofilm inhibition and reduction at the minimum fungicidal concentration on the contact lens surface. Overall, these findings established PS1-3 as a potential candidacidal agent for applications on contact lenses.

Candida Albicans Virulence Factors and Its Pathogenicity

Candida albicans lives as commensal on the skin and mucosal surfaces of the genital, intestinal, vaginal, urinary, and oral tracts of 80% of healthy individuals [...].

Plant-Derived Substances in the Fight Against Infections Caused by Candida Species

Yeast-like fungi from the Candida genus are predominantly harmless commensals that colonize human skin and mucosal surfaces, but under conditions of impaired host immune system change into dangerous pathogens. The pathogenicity of these fungi is typically accompanied by increased adhesion and formation of complex biofilms, making candidal infections challenging to treat. Although a variety of antifungal drugs have been developed that preferably attack the fungal cell wall and plasma membrane, these pathogens have acquired novel defense mechanisms that make them resistant to standard treatment. This causes an increase in the incidence of candidiasis and enforces the urgent need for an intensified search for new specifics that could be helpful, alone or synergistically with traditional drugs, for controlling Candida pathogenicity. Currently, numerous reports have indicated the effectiveness of plant metabolites as potent antifungal agents. These substances have been shown to inhibit growth and to alter the virulence of different Candida species in both the planktonic and hyphal form and during the biofilm formation. This review focuses on the most recent findings that provide evidence of decreasing candidal pathogenicity by different substances of plant origin, with a special emphasis on the mechanisms of their action. This is a particularly important issue in the light of the currently increasing frequency of emerging Candida strains and species resistant to standard antifungal treatment.