Menthol as an effective inhibitor of quorum sensing and biofilm formation in Candida albicans and Candida glabrata by targeting the transcriptional repressor TUP1.

BACKGROUND: Menthol, a natural quorum sensing molecule, is derived from the Mentha species. Combating pathogenicity by inactivating quorum sensing is an emerging approach. Therefore, our objective was to investigate anti-quorum sensing and anti-biofilm potentials of menthol in Candida albicans and Candida glabrata. METHODS: The antifungal properties of menthol were evaluated using a broth microdilution assay and a time-kill assay, and its effects on quorum sensing-mediated virulence factors, cellular reactive oxygen species (ROS), and biofilm formation were tested by evaluating TUP1 expression levels in both C. albicans and C. glabrata. RESULTS: Quorum sensing-mediated virulence factors and biofilm formation were inhibited by menthol in both C. albicans and C. glabrata. Furthermore, coinciding with elevated ROS levels, mRNAs of the quorum sensing-related gene TUP1 were upregulated in both C. albicans and C. glabrata. CONCLUSIONS: This study highlights the anti-quorum sensing potential of menthol through the inhibition of quorum sensing-mediated virulence factors, ROS generation, and biofilm development by targeting TUP1, which could have potential in the treatment of Candida infections.

Association between dietary intake and risk of ovarian cancer: a systematic review and meta-analysis.

PURPOSE: It is unclear how dietary intake influences the ovarian cancer. The present paper sets out to systematically review and meta-analyze research on dietary intake to identify cases having high- or low-risk ovarian cancer. METHODS: Scopus, PubMed, and Wiley Online Libraries were searched up to the date November 24, 2019. Two reviewers were requested to independently extract study characteristics and to assess the bias and applicability risks with reference to the study inclusion criteria. Meta-analyses were performed to specify the relationship between dietary intake and the risk of ovarian cancer identifying 97 cohort studies. RESULTS: No significant association was found between dietary intake and risk of ovarian cancer. The results of subgroup analyses indicated that green leafy vegetables (RR = 0.91, 95%, 0.85-0.98), allium vegetables (RR = 0.79, 95% CI 0.64-0.96), fiber (RR = 0.89, 95% CI 0.81-0.98), flavonoids (RR = 0.83, 95% CI 0.78-0.89) and green tea (RR = 0.61, 95% CI 0.49-0.76) intake could significantly reduce ovarian cancer risk. Total fat (RR = 1.10, 95% CI 1.02-1.18), saturated fat (RR = 1.11, 95% CI 1.01-1.22), saturated fatty acid (RR = 1.19, 95% CI 1.04-1.36), cholesterol (RR = 1.13, 95% CI 1.04-1.22) and retinol (RR = 1.14, 95% CI 1.00-1.30) intake could significantly increase ovarian cancer risk. In addition, acrylamide, nitrate, water disinfectants and polychlorinated biphenyls were significantly associated with an increased risk of ovarian cancer. CONCLUSION: These results could support recommendations to green leafy vegetables, allium vegetables, fiber, flavonoids and green tea intake for ovarian cancer prevention.

Possible mechanisms of the antifungal activity of fluconazole in combination with terbinafine against Candida albicans.

CONTEXT: Candidiasis is a term describing infections by yeasts from the genus Candida, the majority Candida albicans. Treatment of such infections often requires antifungals such as the azoles, but increased use of these drugs has led to selection of yeasts with increased resistance to these drugs. OBJECTIVE: Combination therapy would be one of the best strategies for the treatment of candidiasis due to increased resistance to azoles. MATERIALS AND METHODS: The antifungal activities of fluconazole and terbinafine were evaluated in vitro alone and in combination using broth microdilution test and time kill study. Eventually the expression level of selected genes involved in ergosterol biosynthesis of Candida was evaluated using semi-quantitative RT-PCR. RESULTS: The obtained results showed the significant MICs ranging from 0.25 to 8 µg/mL followed by FICs ranged from 0.37 to 1 in combination with fluconazole/terbinafine. Our findings have demonstrated that the combination of fluconazole and terbinafine could also significantly reduce the expression of ERG1, 3, and 11 in the cell membrane of Candida in all concentrations tested ranging from 1.73- to 6.99-fold. DISCUSSION AND CONCLUSION: This study was undertaken with the ultimate goal of finding the probable targets of fluconazole/terbinafine in C. albicans by looking at its effects on cell membrane synthesis.

Possibility of intrauterine transmission from mother to fetus/newborn: Systematic review and meta-analysis of diagnostic methods to detect SARS-CoV-2 infection.

Several studies have reported vertical transmission of SARS-CoV-2; however, information regarding intrauterine transmission based on diagnostic methods to detect SARS-CoV-2 infection is scarce. A systematic review and meta-analysis was conducted to identify and explore the studies that attempt to ascertain the possibility of intrauterine transmission of SARS-CoV-2 infection according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020) statement. The results demonstrate that SARS-CoV-2 can be transmitted intrauterine, as detected by clinical manifestations (1.00, 95 % CI: 1.00 - 1.00, 0.51, 95 % CI: 0.22 - 0.80), imaging (0.50, 95 % CI: 0.24 - 0.76, 0.03, 95 % CI: 0.00 - 0.17), molecular (1. 00, 95 % CI: 1.00 - 1.00, 0.92, 95 % CI: 0.77 - 1.00), immunological (0.32, 95 % CI: 0.10 - 0.57, 0.34, 95 % CI: 0.11 - 0.61), and histological approaches (0.79, 95 % CI: 0.52 - 0.98) in maternal and fetal/neonatal specimens, respectively. The possibility of intrauterine transmission of SARS-CoV-2 from mother to fetus/newborn was 41 % (95 % CI 0.37 - 0.45). We might confirm/verify the intrauterine transmission of SARS-CoCV-2 from mother to fetus/newborn.

Anti-cancer activity of secreted aspartyl proteinase protein from Candida tropicalis on human cervical cancer HeLa cells.

Cervical cancer is the fourth leading cause of cancer-related death in women worldwide. Microbial products are valuable sources of anti-cancer drugs. The aim of this study was to isolate secreted aspartyl proteinase protein from Candida tropicalis, investigate its inhibitory effect on human cervical cancer HeLa cells, and analyze the expression profiling of selected nuclear stem cell-associated transcription factors. The presence of secreted aspartyl proteinase protein was confirmed by the expression of SAP2 and SAP4 genes in C. tropicalis during the yeast-hyphae transition phase. The enzyme was purified and characterized using the aqueous two-phase system purification method, as well as proteolytic activity and the Bradford and micro-Kjeldahl methods, respectively. The in vitro anti-cancer properties of secreted aspartyl proteinase protein were evaluated by MTT assay, microscopic image analysis, nitric oxide (NO) scavenging activity assay, intracellular reactive oxygen species (ROS) production assay, and RT-qPCR. The isolated C. tropicalis secreted aspartyl proteinase protein exhibited proteinase activity with values ranging from 93.72 to 130.70 µg/mL and 89.88-127.72 µg/mL according to the Bradford and micro-Kjeldahl methods, respectively. Secreted aspartyl proteinase showed effective cytotoxicity in HeLa cell line leading to significant morphological changes. Additionally, it exhibited increased free radical scavenging activity compared to the untreated control group, as evidenced by nitrite inhibition. ROS production increased in HeLa cells exposed to secreted aspartyl proteinase. The expression levels of the nuclear stem cell-associated transcription factors octamer-binding transcription factor 4 (OCT4), sex determining region Y-box 2 (SOX2), and Nanog homeobox (NANOG) were significantly downregulated in the HeLa cells treated with secreted aspartyl proteinase. Secreted aspartyl proteinase protein may be a promising anti-cancer agent, as it effectively affects gene expression and may ultimately reduce the development and progression of cervical cancer. Targeting the genes related to nuclear stem cell-associated transcription factors may provide a novel amenable to cancer treatment.

Possible Molecular Targeting of Biofilm-Associated Genes by Nano-Ag in Candida albicans.

The treatment of candidiasis infections is hindered by the presence of biofilms. Here, we report the biofilm-associated genes as potential molecular targets by silver nanoparticles (nano-Ag) in Candida albicans. Nano-Ag was biosynthesized using Bacillus licheniformis, Bacillus cereus, and Fusarium oxysporum. The physicochemical properties of the microbial-synthesized of nano-Ag are widely characterized by visual observation, ultraviolet-visible spectroscopy, scanning electron microscopy, X-ray diffraction spectroscopy, and Fourier transform infrared spectroscopy. Characterization results revealed the formation of nano-Ag. Antiplanktonic cells and antibiofilm activities of nano-Ag were also demonstrated by minimum inhibition concentrations (MIC), minimum fungicidal concentration (MFC), MFC/MIC ratio, crystal violet staining, 2,3-bis (2-methoxy-4-nitro-5 sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT), and microscopic image analysis. We have analyzed the expressions of biofilm-associated genes in C. albicans treated with different concentrations of nano-Ag based on MIC. The expression profile of BCR1, ALS1, ALS3, HWP1, and ECE1 showed downregulated genes involved in these pathways by the treatment with nanoparticles. Negative regulators, TUP1, NRG1, and TOR1, were upregulated by the treatment of nano-Ag. Our study suggests that nano-Ag affects gene expression and may subsequently decrease the pathogenesis of C. albicans by inhibiting biofilm formation. Molecular targeting of biofilm-associated genes involved in biofilm formation by nano-Ag may be an effective treatment strategy for candidiasis infections.

Antibacterial and Anti-Biofilm Activities of Microbial Synthesized Silver and Magnetic Iron Oxide Nanoparticles Against Pseudomonas aeruginosa.

Pseudomonas aeruginosa is a human bacterial pathogen causing devastating diseases and equipped with various virulence factors like biofilm formation. Common antibiotic treatment has limited efficacy for the P. aeruginosa present in biofilms because of the increased resistance. In this study, we focused our attention on the antibacterial and anti-biofilm activities of various microbial synthesized silver (nano-Ag) and magnetic iron oxide (nano-Fe3O4) nanoparticles against clinical isolates of P. aeruginosa that displayed ceftazidime resistance. The nano-Ag and nano-Fe3O4 represented great antibacterial properties. Nano-Ag and nano-Fe3O4 exhibited a reduction in the biofilm formation by P. aeruginosa reference strain as determined by crystal violet and XTT assays and light microscopy method. Among all, nano-Ag-2 and 7 owing to inherent attributes and mechanisms of resistance in the bacterial biofilm, exhibited anti-biofilm efficacy against ceftazidime resistance clinical isolate of P. aeruginosa. Moreover, nano-Ag and nano-Fe3O4 changed the relative expression of biofilm-associated genes, PELA and PSLA in a concentration dependent manner by P. aeruginosa reference strain. As revealed by qRT-PCR, the expression levels of biofilm-associated genes were downregulated in P. aeruginosa biofilms treated with nano-Ag, while selected biofilm-associated genes were low expressed under treated with nano-Fe3O4. Results of the study demonstrate the potential of microbial synthesized nano-Ag-2 and 7 to act as anti-biofilm agents against ceftazidime resistance clinical isolate of P. aeruginosa. Molecular targeting of biofilm-associated genes by nano-Ag and nano-Fe3O4 may be candidate for new therapeutics against P. aeruginosa diseases.

Biofilm-associated genes as potential molecular targets of nano-Fe3O4 in Candida albicans.

BACKGROUND: There are few effective treatments for Candida biofilm-associated infections. The present study demonstrated changes in the expression of biofilm-associated genes in Candida albicans treated with magnetic iron oxide nanoparticles (denoted as nano-Fe3O4). METHODS: Nano-Fe3O4 was biologically synthesized using Bacillus licheniformis, Bacillus cereus, and Fusarium oxysporum. Additionally, the biologically synthesized nano-Fe3O4 was characterized by visual observation; ultraviolet-visible spectroscopy, scanning electron microscopy, X-ray diffraction spectroscopy, and Fourier transform infrared spectroscopy. The biologically synthesized nano-Fe3O4 was tested for growth and biofilm formation in C. albicans. Furthermore, quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR) was used to study the inhibition of biofilm-associated genes in C. albicans treated with nano-Fe3O4. RESULTS: The production of biologically synthesized nano-Fe3O4 was confirmed using extensive characterization methods. The nano-Fe3O4 inhibited growth and biofilm formation. Nano-Fe3O4 exhibited growth inhibition with minimum inhibition concentrations (MICs) of 50 to 200 µg mL-1. The anti-biofilm effects of nano-Fe3O4 were shown by 2,3-bis (2-methoxy-4-nitro-5 sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT) reduction assay, crystal violet staining, and light field microscopy. The gene expression results showed that the downregulation of BCR1, ALS1, ALS3, HWP1, and ECE1 genes inhibited the biofilm formation in C. albicans. ALS1 reduction was greater than others, with downregulation of 1375.83-, 1178.71-, and 768.47-fold at 2 × MIC, 1 × MIC, and ½ × MIC of nano-Fe3O4, respectively. CONCLUSION: Biofilm-associated genes as potential molecular targets of nano-Fe3O4 in C. albicans may be an effective novel treatment strategy for biofilm-associated infections.

Hyphae-specific genes: Possible molecular targets for magnetic iron oxide nanoparticles alone and combined with visible light in Candida albicans.

Candida albicans readily develops resistance to fluconazole. Magnetic iron oxide nanoparticles (denoted as MION) and antimicrobial photodynamic therapy are attracting attention as therapeutic agents. This study aims to investigate the inhibitory efficacy of MION alone and combined with visible light against C. albicans and expression analysis of hyphal wall protein 1 (HWP1) and agglutinin-like sequence 1 (ALS1) genes in C. albicans. Antifungal susceptibility testing, photodynamic activity assay, reactive oxygen species (ROS) production assay and gene expression analysis were determined in C. albicans treated with MION alone and combined with visible light. MION at 1 × minimum inhibitory concentration (MIC) level (500 µg/mL) exhibited antifungal activity against C. albicans isolates. Further, 1 × MIC levels of MION alone and combined with visible light displayed remarkable fungicidal effects at 24 and 48 h after treatment. The MION combined with visible light caused the highest levels of ROS production by all C. albicans isolates. The relative RT-PCR data showed significant downregulation of HWP1 and ALS1 genes which are the key virulence genes in C. albicans. Differences in gene expression of  HWP1 and ALS1 were more significant in MION combined with visible light treatments than MION alone. Our study sheds a novel light on facile development of effective treatment of C. albicans especially fluconazole-resistant C. albicans infections. The hyphae-specific genes HWP1 and ALS1 could be probable molecular targets for MION alone and combined with visible light in C. albicans.

Immunogenic Evaluation of MPEG-PCL & PLGA Nanoparticles Containing Klebsiella pneumoniae K2O1 Capsular Antigen in Pulmonary Infection Model of Mice.

Klebsiella pneumoniae can cause destructive changes to human lungs if aspirated. The present study aimed to evaluate the immunogenicity of the carriers of Poly lactic-co-glycolic acid (PLGA) and Methoxypoly(ethylene glycol) Poly(caprolactone) (MPEG-PCL) nanoparticles containing the capsular antigen of Klebsiella pneumoniae K2O1 in a model of pulmonary infection in mice as a vaccine candidate. Capsule antigen was extracted from K.pneumoniae K2O1 strain 1053 ATCC 10031 and transported with PLGA or MPEG-PCL nanoparticles as a vaccine in an animal model. The results of FT-IR and AFM confirmed the presence of antigen functional groups in the nanoparticle structure, and semi-spherical shape of the nanoparticles, respectively. The capsular polysaccharide was also used to evaluate the febrileness of the designed vaccine candidates based on the rabbits' pattern, and mortality due to the vaccine candidates in the mice. No fever was observed, and no mortality was observed in the mice. According to the results, the vaccine candidates designed to control the cause of pulmonary infections were effective in the liver, spleen, and lungs of the animals with the ability to enter the first stage of the clinical trial phase.

In vitro investigation of antifungal activity of allicin alone and in combination with azoles against Candida species.

Candidiasis is a term describing infections by yeasts from the genus Candida, and the type of infection encompassed by candidiasis ranges from superficial to systemic. Treatment of such infections often requires antifungals such as the azoles, but increased use of these drugs has led to selection of yeasts with increased resistance to these drugs. In this study, we used allicin, an allyl sulfur derivative of garlic, to demonstrate both its intrinsic antifungal activity and its synergy with the azoles, in the treatment of these yeasts in vitro. In this study, the MIC(50) and MIC(90) of allicin alone against six Candida spp. ranged from 0.05 to 25 microg/ml. However, when allicin was used in combination with fluconazole or ketoconazole, the MICs were decreased in some isolates. Our results demonstrated the existing synergistic effect between allicin and azoles in some of the Candida spp. such as C. albicans, C. glabrata and C. tropicalis, but synergy was not demonstrated in the majority of Candida spp. tested. Nonetheless, In vivo testing needs to be performed to support these findings.

Systematic Review and Meta-Analysis of the Efficacy of Nanoscale Materials Against Coronaviruses-Possible Potential Antiviral Agents for SARS-CoV-2.

The available antiviral agents and their potential for the management of coronavirus disease 2019 (COVID-19) outbreak are important interventions. A systematic review and meta-analysis was performed to summarize the available evidence on the efficacy of nanoscale materials against coronaviruses in vitro and in animal models. PubMed, Scopus and Wiley Online Library databases were searched up to 4 March 2020. Studies that developed the efficacy of nanoscale materials against coronaviruses were included. Two reviewers independently extracted study characteristics and assessed risk of bias and applicability in the included studies. Meta-analyses were conducted to determine the overall inhibition efficacy of nanoscale materials against coronaviruses. A total of 21 studies were identified. Positive association was found between efficacy of nanoscale materials and coronaviruses in vitro and in animal models. The inhibition efficacy of nanoscale materials against coronavirus in vitro and in animal models were 1.84 (95% CI: 1.57, 2.15) and 1.66 (95% CI: 1.36, 2.02), respectively. Results of subgroup analysis of selected studies revealed that the nanoscale materials with spherical morphology were found to be more antiviral activity than the other morphologies against Middle East respiratory syndrome-coronavirus (MERS-CoV) and severe acute respiratory syndrome coronavirus (SARS-CoV). Using systematic review and meta-analysis, our results indicate that nanoscale materials are positive affect against coronaviruses. We might clarify the possible potential for the use of nanoscale materials for SARS-CoV-2.

Inhibitory effect of magnetic iron-oxide nanoparticles on the pattern of expression of lanosterol 14α-demethylase (ERG11) in fluconazole-resistant colonising isolate of Candida albicans.

Fluconazole-resistant Candida albicans is a big scary reality. The authors assessed the antifungal effects of magnetic iron-oxide nanoparticles on fluconazole-resistant colonising isolate of C. albicans and determined the expression of ERG11 gene, protein sequence similarity and ergosterol content. C. albicans isolates were characterised and fluconazole resistance is recognised using World Health Organization's WHONET software. Susceptibility testing of magnetic iron-oxide nanoparticles against fluconazole-resistant colonising isolate of C. albicans was performed according to Clinical and Laboratory Standards Institute guidelines. The expression patterns of ERG11 and protein sequence similarity were investigated. Ergosterol quantification has been used to gauge the antifungal activity of magnetic iron-oxide nanoparticles. The findings indicated that 93% of C. albicans isolates were resistant to fluconazole. Magnetic iron-oxide nanoparticles were presented activity against fluconazole-resistant colonising isolate of C. albicans with minimum inhibitory concentration at 250-500 µg/ml. The expression level of ERG11 gene was downregulated in fluconazole-resistant colonising isolate of C. albicans. The results revealed no differences in fluconazole-resistant colonising isolate of C. albicans by comparison with ERG11 reference sequences. Moreover, significant reduction was noted in ergosterol content. The findings shed a novel light on the application of magnetic iron-oxide nanoparticles in fighting against resistant C. albicans.

Synergistic interaction of fluconazole/sodium bicarbonate on the inhibition of Candida glabrata phospholipase gene

Abstract Candida glabrata infections are responsible for deaths of people globally. Fluconazole is known to be less effective against C. glabrata, which developed many strategies to evade being destroyed by fluconazole. To achieve enhanced efficacy of fluconazole against C. glabrata, the interaction of fluconazole with sodium bicarbonate was investigated using the CLSI guidelines. The efficacy of fluconazole alone and in combination with sodium bicarbonate was evaluated using the time-kill and phospholipase production assays. Eventually, the expression of PLB was assessed using semi-quantitative RT-PCR to investigate the inhibitory properties of fluconazole alone and in combination with sodium bicarbonate against C. glabrata. The fluconazole/sodium bicarbonate combination displayed synergistic and antagonistic effects (FICI= 0.375-4.25). In C. glabrata ATCC, SN 152, and SN 164, the fluconazole/sodium bicarbonate combination exhibited a significant fungicidal activity (p< 0.05) but antagonistic effect in the case of SN 283. With exception of SN 283, a significant reduction was noted in phospholipase production in clinical isolates of C. glabrata treated with fluconazole/sodium bicarbonate combination. The PLB was down-regulated significantly by 0.168-0.515 fold in C. glabrata treated with fluconazole/sodium bicarbonate. The results suggested fluconazole/sodium bicarbonate to have a potential synergistic interaction in C. glabrata, and the underlying mechanism may be associated with phospholipase gene

Expression analysis of drug-resistant gene (blaOXA-51) in carbapenemases producing Acinetobacter baumannii treated with imipenem/sulbactam combination

Drug-resistant Acinetobacter baumannii is a frightening reality. The aim of this study is to examine the expression profiles of blaOXA-51 gene in carbapenemases producing A. baumannii treated with imipenem/sulbactam combination. Carbapenemases producing A. baumannii was identified among clinical isolates of A. baumannii obtained from patients at Shahid Rajaee hospital, Gachsaran, Iran, from January to June 2018. Synergism testing of imipenem/sulbactam on carbapenemases producing A. baumannii was carried out by broth microdilution method. Eventually, the expression of blaOXA-51 gene was carried out to investigate the inhibitory properties of imipenem/sulbactam combination against carbapenemases producing A. baumannii using quantitative real time RT-PCR. Among A. baumannii isolates, 24% were carbapenemases producing A. baumannii. Imipenem/sulbactam combination revealed synergistic and partial synergistic effect for all tested isolates (FIC= 0.313-0.75). Finally, imipenem/sulbactam combination displayed significant down-regulation of blaOXA-51 gene in carbapenemases producing A. baumannii. Imipenem synergizes with sulbactam against carbapenemases producing A. baumannii by targeting of the blaOXA-51 gene.

The anti-obesity effects of Lactobacillus casei strain Shirota versus Orlistat on high fat diet-induced obese rats.

BACKGROUND: Obesity and overweight are major public health problems. Various factors, such as daily nutritional habits, physical inactivity, and genetic, are related to the prevalence of obesity. Recently, it was revealed that the gut microflora may also play an important role in weight management. Thus, this study aimed to determine the anti-obesity effects of Lactobacillus casei strain Shirota (LcS) compared with those of orlistat in an animal model fed a high-fat diet (HFD). DESIGN: Thirty-two male Sprague-Dawley rats were assigned to four groups fed various diets as follows: a standard diet group, HFD group, HFD supplemented with LcS (108109 colony-forming units (HFD-LcS) group, and HFD group treated with Orlistat (10 mg/kg body weight)). After 15 weeks, the weights of organs, body weight, body fat mass and serological biomarkers were measured. In addition, histological analysis of the liver and adipose tissue was performed. RESULTS: Body weight, body mass index, fat mass, leptin and glucose levels were lower, and high-density lipoprotein and adiponectin levels were higher in the HFD-LcS and HFD-orlistat groups than in the HFD group. In addition a significant difference in body fat mass was observed between HFD-LcS group with HFD-orlistat group (19.19±5.76 g vs. 30.19±7.98 g). Although the interleukin-6 level was significantly decreased in the HFD-LcS and HFD-orlistat groups compared with the HFD group, no significant change was observed in other inflammatory biomarkers. CONCLUSION: The results of the present study show that LcS supplementation improves body weight management and the levels of some related biomarkers. In addition, LcS supplementation showed a better result in fat mass and alanine aminotransferase reduction than Orlistat. Further studies are needed to elucidate the anti-obesity effects of LcS, with a longer period of supplementation.

Expression analysis of SIR2 and SAPs1-4 gene expression in Candida albicans treated with allicin compared to fluconazole.

One of the main factors for virulence of fungus such as Candida albicans is the ability to change its morphology from yeast to hyphae. Allicin, one of the volatile sulfur-oil compounds from freshly crushed garlic, has a variety of antifungal activities. In this study, the effect of allicin on growth and hyphae production in C. albicans as compared to fluconazole, an antifungal drug was investigated using survival time in vitro and microscopic image at different time intervals. Additionally, the expression of selected genes involved in hyphae formation and development such as SIR2 and SAP1-4 was evaluated by semi-quantitative RT-PCR and relative real time RT-PCR. Allicin was shown to down-regulate the expression of SIR2 (5.54 fold), similar to fluconazole (3.48 fold) at 2x MIC concentrations. Interestingly, allicin had no effect on SAPs1-4 expression, whereas fluconazole was able to suppress SAP4 expression. Our findings showed that allicin was effective in suppressing hyphae development of C. albicans to an extent that is sometimes equal or more than fluconazole. Moreover, allicin and fluconazole seemed to share a common anti-Candida mechanism through inhibition of SIR2 gene, while fluconazole appeared to also exert its fungistatic effect through another pathway that involved SAP4 suppression.

Differential expression of oil palm pathology genes during interactions with Ganoderma boninense and Trichoderma harzianum.

The expression profiles of Δ9 stearoyl-acyl carrier protein desaturase (SAD1 and SAD2) and type 3 metallothionein (MT3-A and MT3-B) were investigated in seedlings of oil palm (Elaeis guineensis) artificially inoculated with the pathogenic fungus Ganoderma boninense and the symbiotic fungus Trichoderma harzianum. Expression of SAD1 and MT3-A in roots and SAD2 in leaves were significantly up-regulated in G. boninense inoculated seedlings at 21 d after treatment when physical symptoms had not yet appeared and thereafter decreased to basal levels when symptoms became visible. Our finding demonstrated that the SAD1 expression in leaves was significantly down-regulated to negligible levels at 42 and 63 d after treatment. The transcripts of MT3 genes were synthesized in G. boninense inoculated leaves at 42 d after treatment, and the analyses did not show detectable expression of these genes before 42 d after treatment. In T. harzianum inoculated seedlings, the expression levels of SAD1 and SAD2 increased gradually and were stronger in roots than leaves, while for MT3-A and MT3-B, the expression levels were induced in leaves at 3d after treatment and subsequently maintained at same levels until 63d after treatment. The MT3-A expression was significantly up-regulated in roots at 3d after treatment and thereafter were maintained at this level. Both SAD and MT3 expression were maintained at maximum levels or at levels higher than basal. This study demonstrates that oil palm was able to distinguish between pathogenic and symbiotic fungal interactions, thus resulting in different transcriptional activation profiles of SAD and MT3 genes. Increases in expression levels of SAD and MT3 would lead to enhanced resistance against G. boninense and down-regulation of genes confer potential for invasive growth of the pathogen. Differences in expression profiles of SAD and MT3 relate to plant resistance mechanisms while supporting growth enhancing effects of symbiotic T. harzianum.

Comparison between allicin and fluconazole in Candida albicans biofilm inhibition and in suppression of HWP1 gene expression.

Candida albicans is an opportunistic human pathogen with the ability to differentiate and grow in filamentous forms and exist as biofilms. The biofilms are a barrier to treatment as they are often resistant to the antifungal drugs. In this study, we investigated the antifungal activity of allicin, an active compound of garlic on various isolates of C. albicans. The effect of allicin on biofilm production in C. albicans as compared to fluconazole, an antifungal drug, was investigated using the tetrazolium (XTT) reduction-dependent growth and crystal violet assays as well as scanning electron microscopy (SEM). Allicin-treated cells exhibited significant reduction in biofilm growth (p<0.05) compared to fluconazole-treated and also growth control cells. Moreover, observation by SEM of allicin and fluconazole-treated cells confirmed a dose-dependent membrane disruption and decreased production of organisms. Finally, the expression of selected genes involved in biofilm formation such as HWP1 was evaluated by semi-quantitative RT-PCR and relative real time RT-PCR. Allicin was shown to down-regulate the expression of HWP1.

Comparison between efficacy of allicin and fluconazole against Candida albicans in vitro and in a systemic candidiasis mouse model.

The efficacy of allicin compared with fluconazole in alleviating systemic Candida albicans infections was evaluated both in vitro and in vivo through a systemic candidiasis mouse model. Determination of in vitro minimum inhibitory concentrations (MICs) for different C. albicans isolates revealed that both allicin and fluconazole showed different MICs that ranged from 0.05 to 12.5 µg mL(-1) and 0.25 to 16 µg mL(-1) , respectively. A time-kill study showed a significant effect of allicin (P<0.01) against C. albicans, comparable to that of fluconazole. Scanning electron microscopy observation revealed that, similar to fluconazole, allicin produced structural destruction of C. albicans cell surface at low MIC and lysis or puncture at high MIC concentrations. Treatment of BALB/c mice systemically infected with C. albicans showed that although the allicin treatment (at 5 mg kg(-1) day(-1) ) was slightly less efficacious than fluconazole treatment in terms of the fungal load reduction and host survival time, it was still effective against C. albicans in terms of mean survival time, which increased from 8.4 to 15.8 days. These results demonstrate the efficacy of anticandidal effects of allicin both in vitro and in an animal model of candidiasis and affirm the potential of allicin as an adjuvant therapy to fluconazole.