Search

Biofilm-associated Candida infections threaten public health and show high mortality. The drugs used in treatment are very limited due to reasons such as toxicity, low efficacy, and drug resistance, and new alternatives are needed. The use of natural products of plant origin in the biofilm management draws attention. CA (cinnamaldehyde, cinnamic aldehyde, or 3-phenyl-2-propenal) is an essential oil component that can also inhibit mold growth and mycotoxin production. However, there are some limitations in its use due to its poor solubility and volatility in water. Recently, the combination of natural components and nanoparticle-based drug delivery systems shows positive results. In this study, the effects of PLGA (poly(DL-lactide-co-glycolide)) nanoparticles arrested with CA (CA-PLGA NPs) on C. albicans planktonic and biofilm forms (prebiofilm and postbiofilm) were investigated. According to the results, the amount of active ingredient loaded in CA-PLGA NPs is much lower than the free CA and a strong antifungal effect was obtained even at this rate. Also, the postbiofilm application is more effective than prebiofilm application. PLGA NPs can also be a useful carrier for other essential oils, and their potential in various antifungal, antibiofilm, and biomedical applications should be investigated.

Candida species are opportunistic fungi that can cause mucosal or invasive infections. Especially in biofilm-related infections, resistance is very high to anifungals; therefore more effective treatment strategies are needed. Farnesol(3,7,11-trimethyl-2,6,10-dodecatriene-1-ol) is the quorum sensing (QS) signal molecule and can interact with Candida species both as a QS molecule and as an exogenous agent. The aim of this study was to investigate the effects of farnesol on both the planktonic and biofilm forms of Candida species by colorimetric, microbiological, and electron microscopic methods. Obtained results demonstrated the inhibitory effect of farnesol on the planktonic and biofilm forms of Candida. Farnesol showed a biofilm-enhancing effect at lower concentrations. TEM findings showed the membrane and wall damage, vacuolization, or granulation in cells. SEM images confirmed biofilm reduction in pre-/post-biofilm applications as a result of farnesol treatment. In conclusion, farnesol can be used as an alternative agent to reduce the Candida biofilms, with future studies.

In our study, green synthesis of silver nanoparticles was carried out using a red algae Gelidium corneum extract as reducing agent. The obtained silver nanoparticles were characterized by UV–vis, TEM, XRD, FTIR and ICP-MS measurements. FTIR measurements indicated the possible functional groups responsible for the stabilization and reduction of nanoparticles, while XRD analysis results explained the crystalline structure of the particles with centric cubic geometry. TEM micrographs showed that the size of the nanoparticles was between 20–50 nm. According to the broth microdilution test results, AgNPs showed a high antimicrobial activity with very low MIC values (0.51 μg/ml for Candida albicans yeast and 0.26 μg/ml for Escherichia coli bacteria). The different ultrastructural effects of silver nanoparticles on yeast and bacterial cells were observed by TEM. Antibiofilm efficacy studies were also examined in two stages as prebiofilm and postbiofilm effect. In prebiofilm effect studies, AgNPs (0.51 μg/ ml) exhibited 81% reducing effect on biofilm formation. The highest reduction rate in postbiofilm studies was 73.5% and this was achieved with 2.04 μg/ml AgNPs. Our data support that the silver nanoparticles obtained by this environmentally friendly process have potential to be used for industrial and therapeutic purposes.

In this study, the culture requirements of the Cerrena unicolor OBCC 5005 strain were determined to optimize bioactive exopolysaccharide production in submerged culture. The effects of initial medium pH, carbon and nitrogen sources, inoculum age and amount, and mineral source on exopolysaccharide and mycelial biomass production by the C. unicolor OBCC 5005 strain were studied using a one-factor-at-a-time method. The highest exopolysaccharide production was obtained when culture parameters were used as initial medium pH: 5.5, 5% sucrose, 5% mycological peptone, and 5% of 4-day inoculants in the presence of 5 mM Fe2+. Optimized culture conditions at a flask scale were applied to a 3-L stirred tank reactor. As a result, 7.92 g/L and 7.34 g/L maximum exopolysaccharide production in optimized conditions at flask and stirred-tank reactor scales were achieved, respectively. The present study is the first to prove that C. unicolor can yield high bioactive exopolysaccharide production at flask and stirred-tank reactor scales.

Isophorone (3,5,5-trimethyl-2-cyclohexen-1-one), a monoterpene, and the structurally related 1,8-cineole and camphor, have demonstrated a protective effect against cancer, biological activity against a variety of microorganisms, and anti-oxidant properties. The derivatization of isophorone is, therefore, an important field of xenobiochemistry, pharmacology and toxicology. The aim of this study was to obtain derivatives of isophorone through microbial biotransformation and evaluate the biotransformation metabolites as potential antimicrobial agents. Incubation of isophorone with the fungi Alternaria alternata and Neurospora crassa afforded 4a-hydroxy- and 7-hydroxy-isophorone as transformation metabolites. The antimicrobial activities of isophorone and the metabolites were evaluated in vitro both by using agar dilution and microdilution methods. However, no significant antibacterial activity was observed when compared with those of standard substances.

Isophorone (3,5,5-trimethyl-2-cyclohexen-1-one), a monoterpene, and the structurally related 1,8-cineole and camphor, have demonstrated a protective effect against cancer, biological activity against a variety of microorganisms, and anti-oxidant properties. The derivatization of isophorone is, therefore, an important field of xenobiochemistry, pharmacology and toxicology. The aim of this study was to obtain derivatives of isophorone through microbial biotransformation and evaluate the biotransformation metabolites as potential antimicrobial agents. Incubation of isophorone with the fungi Alternaria alternata and Neurospora crassa afforded 4α-hydroxy- and 7-hydroxy-isophorone as transformation metabolites. The antimicrobial activities of isophorone and the metabolites were evaluated in vitro both by using agar dilution and microdilution methods. However, no significant antibacterial activity was observed when compared with those of standard substances.

WOS: 000209805600629, …