Fungal Candida Albicans Research Articles

A CO2 sensing module modulates β-1,3-glucan exposure in Candida albicans.

Microbial species capable of co-existing with healthy individuals, such as the commensal fungus Candida albicans, exploit multifarious strategies to evade our immune defenses. These strategies include the masking of immunoinflammatory pathogen-associated molecular patterns (PAMPs) at their cell surface. We reported previously that C. albicans actively reduces the exposure of the proinflammatory PAMP, β-1,3-glucan, at its cell surface in response to host-related signals such as lactate and hypoxia. Here, we show that clinical isolates of C. albicans display phenotypic variability with respect to their lactate- and hypoxia-induced β-1,3-glucan masking. We have exploited this variability to identify responsive and non-responsive clinical isolates. We then performed RNA sequencing on these isolates to reveal genes whose expression patterns suggested potential association with lactate- or hypoxia-induced β-1,3-glucan masking. The deletion of two such genes attenuated masking: PHO84 and NCE103. We examined NCE103-related signaling further because NCE103 has been shown previously to encode carbonic anhydrase, which promotes adenylyl cyclase-protein kinase A (PKA) signaling at low CO2 levels. We show that while CO2 does not trigger β-1,3-glucan masking in C. albicans, the Sch9-Rca1-Nce103 signaling module strongly influences β-1,3-glucan exposure in response to hypoxia and lactate. In addition to identifying a new regulatory module that controls PAMP exposure in C. albicans, our data imply that this module is important for PKA signaling in response to environmental inputs other than CO2.IMPORTANCEOur innate immune defenses have evolved to protect us against microbial infection in part via receptor-mediated detection of "pathogen-associated molecular patterns" (PAMPs) expressed by invading microbes, which then triggers their immune clearance. Despite this surveillance, many microbial species are able to colonize healthy, immune-competent individuals, without causing infection. To do so, these microbes must evade immunity. The commensal fungus Candida albicans exploits a variety of strategies to evade immunity, one of which involves reducing the exposure of a proinflammatory PAMP (β-1,3-glucan) at its cell surface. Most of the β-1,3-glucan is located in the inner layer of the C. albicans cell wall, hidden by an outer layer of mannan fibrils. Nevertheless, some β-1,3-glucan can become exposed at the fungal cell surface. However, in response to certain specific host signals, such as lactate or hypoxia, C. albicans activates an anticipatory protective response that decreases β-1,3-glucan exposure, thereby reducing the susceptibility of the fungus to impending innate immune attack. Here, we exploited the natural phenotypic variability of C. albicans clinical isolates to identify strains that do not display the response to β-1,3-glucan masking signals observed for the reference isolate, SC5314. Then, using genome-wide transcriptional profiling, we compared these non-responsive isolates with responsive controls to identify genes potentially involved in β-1,3-glucan masking. Mutational analysis of these genes revealed that a sensing module that was previously associated with CO2 sensing also modulates β-1,3-glucan exposure in response to hypoxia and lactate in this major fungal pathogen of humans.

Immunity to pathogenic mucosal C. albicans infections mediated by oral megakaryocytes activated by IL-17 and candidalysin

The fungus Candida albicans can cause mucosal infections including oropharyngeal candidiasis (OPC) in immunocompromised patients. In humans, an increased risk of fungal infections correlates with thrombocytopenia. However, our understanding of platelets and megakaryocytes in mucosal fungal infections is almost entirely unknown. When megakaryocyte- and platelet-depleted mice were infected with OPC, the tongue showed higher fungal burden, due to decreased neutrophil accumulation. Protection depended on a distinct population of oral-resident megakaryocytes. Interleukin-17, important in antifungal immunity, was required since mice lacking the IL-17 receptor had decreased circulating platelets and their oral megakaryocytes did not expand during OPC. The secretion of the peptide toxin candidalysin activated human megakaryocytes to release platelets with antifungal capacity. Infection with a candidalysin-deficient strain resulted in decreased expansion of tongue megakaryocytes during OPC. This is the first time that a distinct megakaryocyte population was identified in the oral mucosa that is critical for immunity against fungal infection.

Silver and Antimicrobial Polymer Nanocomplexes to Enhance Biocidal Effects.

Antimicrobial resistance has become a major problem over the years and threatens to remain in the future, at least until a solution is found. Silver nanoparticles (Ag-NPs) and antimicrobial polymers (APs) are known for their antimicrobial properties and can be considered an alternative approach to fighting resistant microorganisms. Hence, the main goal of this research is to shed some light on the antimicrobial properties of Ag-NPs and APs (chitosan (CH), poly-L-lysine (PLL), ε-poly-L-lysine (ε-PLL), and dopamine (DA)) when used alone and complexed to explore the potential enhancement of the antimicrobial effect of the combination Ag-NPs + Aps. The resultant nanocomplexes were chemically and morphologically characterized by UV-visible spectra, zeta potential, transmission electron microscopy, and Fourier-transform infrared spectroscopy. Moreover, the Ag-NPs, APs, and Ag-NPs + APs nanocomplexes were tested against Gram-positive Staphylococcus aureus (S. aureus) and the Gram-negative Escherichia coli (E. coli) bacteria, as well as the fungi Candida albicans (C. albicans). Overall, the antimicrobial results showed potentiation of the activity of the nanocomplexes with a focus on C. albicans. For the biofilm eradication ability, Ag-NPs and Ag-NPs + DA were able to significantly remove S. aureus preformed biofilm, and Ag-NPs + CH were able to significantly destroy C. albicans biofilm, with both performing better than Ag-NPs alone. Overall, we have proven the successful conjugation of Ag-NPs and APs, with some of these formulations showing potential to be further investigated for the treatment of microbial infections.

Synthesis, properties and applications of sulfur doped (CdO)1-x(Mn3O4)x (x = 0.0/0.25/0.50/0.75/1.0) nanocrystals

Studies have been made to understand the effect of anionic doping (with 2.5 wt% sulfur) on the physicochemical properties and photocatalytic, and antimicrobial activity applications of the interesting and useful (CdO)1-x(Mn3O4)x (x = 0.0/0.25/0.50/0.75/1.0) nanocrystals (synthesized by a microwave-assisted solvothermal method, and annealed at 650 °C). X-ray diffraction, electron microscopic (SEM/TEM) and EDX spectral analyses have shown that the synthesized samples are of high phase purity having spherical shaped morphology with crystallite sizes in the range of 11–22 nm. UV–visible spectral (in the wavelength range 200–800 nm) and AC electrical measurements (in the temperature range 40–160 °C and with frequency range 100 Hz–1 MHz) have indicated tuning of optical and electrical properties on doping. Capability in photocatalytic degradation (with Methylene Blue dye under UV–visible light irradiation) and antimicrobial activity (against gram positive Bacillus Subtiles, gram negative Escherichia Coli and fungus Candida Albicans) have also been studied for the 10 samples (including the 5 un-annealed samples) considered.

Different wavelengths of laser: are they significant for treatment of denture stomatitis?: an in-vitro study

BackgroundDenture stomatitis (DS) is an inflammatory disorder that affects the mucosal surface underneath the dentures and frequently causes oral mucosal irritation, discomfort, and altered taste perception, which prevents people from consuming enough nutrients. One of the main causes of DS is an overgrowth of the fungus Candida albicans (C. albicans). A possible alternative treatment for Candida infections is thought to be laser therapy. The aim of this study was to evaluate how different wavelengths of laser would affect growth and pathogenic properties of Candida albicans.MethodsA concentration of 106 viable cells/ml of Candida albicans were used in the preparation process. Four groups were created from the specimens. Culturing of the control group was completed with no intervention. The other 3 groups received laser radiation for 60 seconds at a power of 1W. The 2nd and 3rd groups were irradiated with diode laser at a wavelength of 940 nm and 980 nm respectively. The 4th group was irradiated with Nd-YAG laser at a wavelength of 1064 nm. Turbidimetric growth was defined as variations in the optical density of fungal growth. These measures were made at three different times: baseline, 48 hours, and 72 hours.ResultsIn both groups of diode laser, the growth of Candida albicans showed no remarkable differences at baseline, after 48 and 72 hours using a power of 1 W and duration of 60 seconds. The Nd-YAG group showed significant increase in optical density after 48 hrs then significant decrease after 72 hrs. The optical density values in the control group showed no notable difference between the control and diode study groups at different time periods. However, the Nd:YAG group showed a statistically significant difference compared to the control and the 2 diode laser groups.ConclusionsDifferent laser parameters have a different effect on growth and pathogenic properties of Candida albicans. Diode laser therapy with wavelengths 940 and 980 nm used in continuous mode with power of 1 W for duration of 60 seconds can result in proliferation of Candida albicans instead of destroying them. Nd:YAG laser, used in pulsed mode, with power of 1 W for a duration of 60 seconds can be used to destroy Candida albicans and therefore, can be used as an effective treatment for denture stomatitis.

Antimicrobial Evaluation of Anthraquinones and Preanthraquinone from the Root Extract of Aloe kefaensis

The aim of this study was to isolate antimicrobial compounds from the roots of Aloe kefaensis, a plant endemic to Ethiopia and used to treat various microbial infections by traditional healers. The air-dried and powdered plant material was sequentially extracted with petroleum ether, dichloromethane, acetone, and methanol. Then, each solvent extract was evaluated for its in vitro antimicrobial activity against four bacterial (Escherichia coli, Bacillus cereus, Salmonella typhimurium, and Staphylococcus aureus) and one fungal (Candida albicans) strains using the agar disk diffusion method. Superior antimicrobial activity was exhibited against all the strains by dichloromethane extract, with the highest activity observed against S. typhi (inhibition zone diameter of 23.0 mm at 200 mg/mL). Due to similarity in their TLC profile, the acetone and dichloromethane extracts were combined and subjected to silica gel column chromatography for fractionation and isolation of the compounds. Separation of these extracts using silica gel column chromatography resulted in four anthraquinones: deoxyerythrolaccin (1), chrysophanol (2), laccaic acid D-methyl ester (3), and 3, 8-dihydroxy-1-methylanthraquinone-2-carboxylic acid (4) and one preanthraquinone, aloesaponol II (5). The structure of these compounds was established using NMR (1D and 2D) spectroscopic analysis and comparison with reported literature data. The isolated compounds were evaluated for antimicrobial activity and showed varying degrees of potency. Compounds 2 and 4 showed the highest activity against Salmonella typhimurium at 10 mg/mL, with a zone of inhibition of 28.5 and 25.0 mm, respectively, in comparison to gentamicin (26.0 mm inhibition zone diameter at 10 mg/mL). Therefore, this strong antimicrobial activity of the extracts and isolates supports the traditional usage of Aloe kefaensis to treat microbial diseases.

RFX transcription factor in the human-associated yeast Candida albicans regulates adhesion to oral epithelium.

Adhesion to mucosal surfaces is a critical step in many bacterial and fungal infections. Here, using a mouse model of oral infection by the human fungal pathobiont Candida albicans, we report the identification of a novel regulator of C. albicans adhesion to the oral mucosa. The regulator is a member of the regulatory factor X (RFX) family of transcription factors, which control cellular processes ranging from genome integrity in model yeasts to tissue differentiation in vertebrates. Mice infected with the C. albicans rfx1 deletion mutant displayed increased fungal burden in tongues compared to animals infected with the reference strain. High-resolution imaging revealed RFX1 transcripts being expressed by C. albicans cells during infection. Concomitant with the increase in fungal burden, the rfx1 mutant elicited an enhanced innate immune response. Transcriptome analyses uncovered HWP1, a gene encoding an adhesion protein that mediates covalent attachment to buccal cells, as a major RFX1-regulated locus. Consistent with this result, we establish that C. albicans adhesion to oral cells is modulated by RFX1 in an HWP1-dependent manner. Our findings expand the repertoire of biological processes controlled by the RFX family and illustrate a mechanism whereby C. albicans can adjust adhesion to the oral epithelium.

Antimicrobial, Antioxidant Activities, and Phytochemical Characterization of Acacia nilotica and Hibiscus sabdariffa

Antibiotic abuse has caused the emergence of an alarming number of resistant pathogens. Hence, there is an urgent need for novel agents. Most of the Sudanese people in rural areas rely on traditional medicine for the treatment of many infectious diseases. This study was carried out to investigate the antimicrobial antioxidant activities and phytochemical contents of Hibiscus sabdariffa fruits and Acacia nilotica pods. Antimicrobial assays of the ethanolic extracts of both plants showed that they exhibit diverse inhibitory activity against Gram-positive Staphylococcus aureus, and three Gram-negative bacteria Salmonella typhi, Klebsiella and Escherichia coli, and one fungi Candida albicans, with the zone of inhibition ranging from 16 to 20 mm in length. The antioxidant activity of A. nilotica was about 91 %; it was highly significant compared with the standard (Propyl gallate) which gave (94%). While the extract of H. sabdariffa showed weak antioxidant activity. Phytochemical screening of A. nilotica indicates the presence of phenols, tannins, flavonoids, triterpenes, and saponins, while alkaloids were absent. The extract H. sabdariffa was rich in phenols, flavonoids, and alkaloids, but no tannins, triterpenes, or saponins were detected. These findings provide scientific evidence to support the traditional medicinal uses of these extracts and indicate the promising potential of these plants for medicinal purposes.

DOUBLE-DOPED CALCIUM PHOSPHATE COATINGS WITH ANTIMICROBIAL EFFICACY FOR BIODEGRADABLE METAL BIOMEDICAL IMPLANTS

Over the last decades, biodegradable metals emerged as promising materials for various biomedical implant applications, aiming to reduce the use of permanent metallic implants and, therefore, to avoid additional surgeries for implant removal. However, among the important issue to be solved is their fast corrosion - too high to match the healing rate of the bone tissue. The most effective way to improve this characteristic is to coat biodegradable metals with substituted calcium phosphates. Tricalcium phosphate (β-TCP) is a resorbable bioceramic widely used as synthetic bone graft. In order to modulate and enhance its biological performance, the substitution of Ca2+ by various metal ions, such as strontium (Sr2+), magnesium (Mg2+), iron (Fe2+) etc., can be carried out. Among them, copper (Cu2+), manganese (Mn2+), zinc (Zn2+) etc. could add antimicrobial properties against implant-related infections. Double substitutions of TCP containing couples of Cu2+/Sr2+ or Mn2+/Sr2+ ions are considered to be the most perspective based on the results of our study. We established that single phase Ca3−2x(MˊMˊˊ)x(PO4)2 solid solutions are formed only at x ≤ 0.286, where Mˊ and Mˊˊ—divalent metal ions, such as Zn2+, Mg2+, Cu2+, Mn2+, and that in case of double substitutions, the incorporation of Sr2+ ions allows one to extend the limit of solid solution due to the enlargement of the unit cell structure. We also reported that antimicrobial properties depend on the substitution ion occupation of Ca2+ crystal sites in the β-TCP structure. The combination of two different ions in the Ca5 position, on one side, and in the Ca1, Ca2, Ca3, and Ca4 positions, on another side, significantly boosts antimicrobial properties. In the present work, zinc-lithium (Zn-Li) biodegradable alloys were coated with double substituted Mn2+/Sr2+ β-TCP and double substituted Cu2+/ Sr2+ β-TCP, with the scope to promote osteoinductive effect (due to the Sr2+ presence) and to impart antimicrobial properties (thanks to Cu2+ or Mn2+ ions). The Pulsed Laser Deposition (PLD) method was applied as the coating's preparation technique. It was shown that films deposited using PLD present good adhesion strength and hardness and are characterized by a nanostructured background with random microparticles on the surface. For coatings characterization, Fourier Transform Infrared Spectroscopy, X-ray Diffraction, and Scanning Electron Microscopy coupled with Energy Dispersive X-ray and X-ray Photoelectron Spectroscopy were applied. The microbiology tests on the prepared coated Zn-Li alloys were performed with the Gram-positive (Staphylococcus aureus, Enterococcus faecalis) and Gram-negative (Salmonella typhimurium, Escherichia coli) bacteria strains and Candida albicans fungus. The antimicrobial activity tests showed that Mn2+/Sr2+ β-TCP -coated and Cu2+/Sr2+ β-TCP coated Zn-Li alloys were able to inhibit the growth of all five microorganisms. The prepared coatings are promising in improving the degradation behavior and biological properties of Zn-Li alloys, and further studies are necessary before a possible clinical translation.

Activation of CD4+CD25+CD45+ T-lymphocytes by Candida albicans in vitro in patients with leukoplakia associated with candidal stomatitis

The mechanisms and patterns of T-lymphocyte activation in response to the effects of Candida albicans are currently insufficiently studied. Therefore, the study of of lymphocytes expressing CD4, CD25, CD45 against the background of precancer and cancer of the oral mucosa is very relevant. The purpose of the study was to study the in vitro effect of Candida albicans on the expression of CD4+CD25+CD45+ T-lymphocytes in the blood of patients with candidal stomatitis with and without leukoplakia. Material and methods. The study involved 93 patients with candidal stomatitis (with and without leukoplakia) aged from 36 to 79 years with chronic and recurrent candidiasis. 30 patients with leukoplakia without candidal stomatitis aged from 38 to 71 years old. The control group consisted of 30 patients aged from 34 to 75 years without candidal stomatitis and leukoplakia. Leukocytes from peripheral blood patients were incubated for 24 hours at 37°C with 2.5 μl of Candida albicans (experimental sample) and with 2.5 μl of buffered saline (control sample). The cells were then phenotyped with CD4+CD25+CD45+ monoclonal antibodies. Conclusions. In the control sample, CD25 expression was higher in the groups of patients with candidiasis (with and without leukoplakia). The expression of activation markers – CD25+-increased on patient lymphocytes in the experimental sample. There were more activated T lymphocytes in response to stimulation by fungi of the genus Candida albicans (p<0.05), compared to lymphocytes in the control sample. The main increase was observed in the group of patients with leukoplakia, candidal stomatitis and endothelial dysplasia, in which Treg lymphocytes were determined. These data confirm the presence of a pronounced response of CD4+ T lymphocytes to fungi of the genus Candida albicans in patients with candidal stomatitis.

Optimization of green microwave-assisted extraction of essential oil from lemon (Citrus limon) leaves: Bioactive, antioxidant and antimicrobial potential

This research delves into the analysis of essential oil derived from Citrus limon leaves cultivated in the northern region of Bangladesh, focusing on their potential attributes. The essential oil was extracted employing a microwave-assisted gravity station without using solvent. Optimization was carried out in terms of time, temperature and power as a function of oil yield. The study revealed the highest oil yield of 2.5 % after 50 min at 110 °C, maintaining a microwave power of 300 watt. Twenty-four (24) phyto-components were identified by Gas Chromatogram- Mass Spectrometer (GC-MS) where d-Limonene (34.10660 %) was dominant compound. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was used to assess the antioxidant activity of essential oil. Notably, essential oil displayed superior DPPH radical scavenging activity (IC50 8.57 ppm) compared to butylated hydroxytoluene (BHT) (IC50 10.63 ppm), a common antioxidant standard. Furthermore, a variety of harmful microorganisms were used to evaluate the antimicrobial efficacy. The extracted essential oil exhibited the strongest antimicrobial effectiveness against bacteria Staphylococcus aureus (ZOI-27.50 mm, MIC-7.8 μL/mL) and the fungi Candida albicans (ZOI-32.83 mm, MIC-1.95 μL/mL). These findings demonstrate the Citrus limon leaves essential oil contains bioactive components with strong antioxidant and antimicrobial properties. The extracted essential oil holds significant potential for applications in the foods, pharmaceuticals and cosmetic industries.

Antibacterial Activity Assessment of Chitosan/Alginate Lavender Essential Oil Membranes for Biomedical Applications.

The demand for natural products in the treatment of dermatological pathologies has boosted the use of bioactive substances such as lavender essential oil (LEO), which stands out for its anti-inflammatory and antioxidant properties and its antimicrobial potential. Biopolymers such as chitosan (CHT) and alginate (ALG) are biodegradable and biocompatible and have proven their viability in biomedical applications such as skin regeneration. The inhibitory effect of LEO on the growth of skin-related bacterial species Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa and the fungus Candida albicans was studied by incorporating 1% v/v LEO encapsulated in CHT, ALG, and CHT/ALG membranes. Despite the verification of the antimicrobial effect of all type of membranes, no synergistic effect was observed following the addition of LEO. S. aureus and P. aeruginosa showed the most growth on the different substrates and C. albicans demonstrated the highest inhibition. This is a first approach using microorganisms isolated from clinical samples or skin microbiota. Further investigation would be advisable using more clinical strains for each microorganism to validate their biomedical applicability.

Evaluation of Antimicrobial Activity and Physical Properties of Vinyl Siloxane Ether Impression Material Modified with Zinc Oxide and Chitosan Nanoparticles: An In-vitro Study

Introduction: The antimicrobial activity and physical properties of Vinyl Siloxane Ether (VSE) impression material, such as dimensional stability, flow, and setting time, play a crucial role in the success of fixed prosthodontics. During impression making, the impression material is exposed to infected blood and saliva, which are potential sources of cross-contamination. Cross-contamination can be decreased or minimised when antimicrobial agents are added to the impression material. The efficacy of nanoparticles like silver, titanium, zinc oxide, and chitosan as antimicrobial agents is continuously researched in dentistry. These particles have the benefit of being small and possessing effective antibacterial characteristics due to their vast surface area, which creates an effective interaction with microbes. Aim: To evaluate and compare the antimicrobial activity and physical properties of VSE impression material incorporated with various concentrations (0.0, 1.0, and 2.5 wt.%) of zinc oxide and chitosan nanoparticles. Materials and Methods: This is an in-vitro study conducted in the Department of Prosthodontics at KIMS Dental College and Hospital, Amalapuram, Andhra Pradesh, India. Ethical Review Board for clinical trials (Material protocol no. 020/ KIMS DENTAL/2022). The study was conducted in the month of June and July of 2022 year. A total of 252 samples were fabricated with VSE impression material and divided into two groups for antimicrobial activity (Staphylococcus aureus, Pseudomonas aeruginosa, and the fungus Candida albicans) and physical properties (dimensional stability, flow, setting time) with 126 samples in each group, respectively. The sample size was estimated using G Power One software with a power of 91% and an alpha error of 5%. Antimicrobial activity was determined using the disk diffusion method, dimensional stability was determined with a stereomicroscope, setting time with a Gillmore apparatus, and flow with a vernier caliper. Data were subjected to one-way Analysis of Variance (ANOVA) (p-value <0.05), T tests, and Tukey post-hoc tests, respectively. A p-value of ≤0.05 was considered statistically significant. Results: Significant changes were noted against Staphylococcus aureus bacteria when VSE was incorporated with 2.5% zinc oxide nanoparticles (p-value=0.010). The highest setting time was found for 2.5% chitosan, and the lowest setting time was for 2.5% zinc oxide (p-value <0.001). Decreased flow was observed with 2.5% chitosan, whereas increased flow was observed with 1% and 2.5% of zinc oxide nanoparticles (p-value=0.016). Enhanced dimensional stability was seen when the impression material was incorporated with 1% and 2.5% of ZnO nanoparticles (p-value <0.001). Conclusion: Based on this in-vitro study, zinc oxide and chitosan nanoparticles can be incorporated into VSE impression material as antimicrobial agents without adversely affecting their properties.

In vitro and in silico studies of alpha glucosidase inhibition and antifungal activity of coffea canephora husk.

The coffea canephora husk, a protected agricultural crop, is abundant in Vietnam. Examining the effects of C. canephora husk compounds on α-glucosidase and antifungal drug activity was the primary objective of this research. A cholestane-type steroid, coffeacanol A (1), was extracted from the ethyl acetate extract. Three cholestane-type derivatives (2-4) and three additional known compounds (5-7) were separated, and we used a variety of chromatographic techniques to identify a total of six substances. We used NMR to determine the chemical structures of these substances. Extensive HR-MS-ESI analysis and NMR experimental data were used to confirm the structure of the novel metabolite (1). The cholestane-type steroid was initially discovered in the Coffea canephora husk, marking the first instance in the coffee plant family to reveal chemical structures (1-7). The inhibition of α-glucosidase was found to be significantly higher in all compounds tested, with the exception of compounds (2) and (5). In vitro, the positive control showed the lowest inhibition, and the range of IC50 values was calculated to be 27.4 to 96.5 μM, which is lower than the IC50 value of 214.50 μM for the acarbose control. With an IC50 value of 27.4 μM, compound (7) showed the greatest capacity to inhibit α-glucosidase among the test compounds. The 3TOP and 2VF5 enzyme crystal structures were used for in silico docking investigations and validations of compounds (1-7). In silico calculations to explain how compound (7) shows high activity in vitro via the enzyme inhibition mechanism by residual amino acids, like Gly 1102 (B chain) and Glu 1095 (B chain), and their relative interaction with compounds (7) and acarbose. Compound (7) exhibited the best antifungal activity against Candida albicans fungus among three fungi, namely Candida albicans, Trichophyton mentagrophytes, and Trichophyton rubrum, with a MIC value of 25 μM. Compound (7) and fluconazole combined to form similar interactions in the contact ligand model, including the functional group, capping group, and linker part, which interacted fully with the 2VF5 enzyme, leading to effective in vitro inhibition.

Phytoconstituents profiling of indigenous herbal drugs and its in vitro microbial, in silico biological examination against Severe acute respiratory syndrome coronavirus 2

Background: Habb-E-Shifa, Hamdard Sualin, and Hamdard Joshanda traditional herbal medicines may promote host resistance against infection by bacteria, viruses, and fungi which are easily accessible at inexpensive with no complexity. These herbal medicines are used to cure sore throat, cough, fever, lung cancer, and asthma patients in developing South Asian countries. These traditional herbal medicines acted a crucial role in the prevention and control of coronavirus disease 2019 (COVID-19). Aims and Objectives: This research article aimed at conducting phytochemistry, antimicrobial activity, COVID-19 docking and some spectroscopic (Infrared, Ultraviolet, 13C-Nuclear Magnetic Resonance (13C-NMR), 1H-NMR, and Mass Spectra) characterizations of the polyherbal drugs were carried out. Additionally, In-vitro and In-silico analyses were performed to measure activity against COVID-19. High Performance - Liquid Chromatography (HPLC), Gas Chromatography - Mass Spectrometry (GC-MS), antimicrobial, and docking studies were carried out. The preliminary phytochemical assay and bioactive compounds were screened using HPLC and GC-MS. The study is an attempt to assess the promising effects of selected polyherbal indigenous drugs such as Habb-E-Shifa, Hamdard Sualin, and Hamdard Joshanda phytoconstituents against the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Materials and Methods: The extract of the selected polyherbal formulations showed high-to-moderate preventive effects on the growth inhibition in the pathogenic bacterium, namely Streptococcus oralis, Staphylococcus aureus, Propionibacterium acnes, Pseudomonas aeruginosa, Escherichia coli, and Proteus vulgaris, and three fungal Candida albicans, Aspergillus fumigatus,and Aspergillus niger. Further docking study evaluates the pharmacological activity of bioactive chemical compounds with SARS-CoV-2 NSP5 (PDB ID: 7nxh) and SARS-CoV-2 Omicron spike protein with human angiotensin-converting enzyme 2 (ACE-2) (PDB ID: 7wk6). Results: In this study, for the first time, we attempted to examine some spectroscopic characterization of selected herbals. The total phenol content (1.66, 1.55, and 1.13 mg/mL) and total flavonoid content (4.92, 0.49, and 0.50 mg/mL) were present in the extracted samples of Habb-E-Shifa (H), Hamdard Joshanda (J), and Hamdard Sualin (S). Studies on COVID-19 docking infer the affinity of the herb's chemical components toward COVID-19 protease and ACE-2 receptor by establishing excellent binding capacity in complex formation. The results confirmed that polyherbal drugs harbor biological activities and thereby highlight that these extracts can serve as a remedy for antimicrobial and COVID-19. Conclusions: The research article confirms the remarkable potential in exhibiting antimicrobial activity against Gram-positive, Gram-negative bacteria and fungi. These herbal medicines such as Habb-E-Shifa (H), Hamdard Joshanda (J), and Hamdard Sualin (S) showed a vital role against SARS-CoV-2 Omicron spike protein with human ACE2 (7wk6) and amino acids of SARS-CoV-2 NSP5 (7nxh). Our study provides obvious evidence supporting dietary therapy and herbal medicine as potentially effective against SARS-CoV-2. Based on present studies, these herbal products can be introduced as preventive and therapeutic agents fight against coronavirus.

Volatile chemical profiling and distinction of Citrus essential oils by GC analyses with correlation matrix; evaluation of its in vitro radical scavenging and microbicidal efficacy

Leaf volatile oil compositions of five Citrus species viz., Citrus aurantifolia, Citrus limon, Citrus maxima, Citrus medica and Citrus medica * Citrus limon were examined in this study by Gas Chromatography-Flame Ionisation Detector (GC-FID) and Gas Chromatography-Mass Spectrometry (GC–MS) analysis and percentage volatile compositions were compared. Thirty-eight compounds were identified that account for 90 to 99 % of essential oil composition from Citrus species, respectively. GC–MS profiling of essential oils revealed that Citrus leaf oils were predominantly characterized by limonene (15.76±0.01% to 29.36±0.46%) as one of the major constituents. Monoterpenoids (77.38±0.19% to 98.05±0.05%) are the prominent class of constituents present in the volatile oils of four Citrus plants under study whereas in one species (C. maxima), sesquiterpene hydrocarbons (38.97±0.21%) were the dominant category. The data from GC analyses were subjected to correlation study to analyse the correlation between the volatile constituents among the selected Citrus species. These essential oils were initially evaluated for their antioxidant capacity and the leaf oils exhibited promising radical scavenging property with an average IC50 value of 29.15±0.01 μg/mL. This study was further designed to evaluate antimicrobial efficacy of five Citrus leaf essential oils against various pathogenic bacterial and fungal strains. Four examined essential oils gave a comparative antibacterial activity with a minimum inhibitory concentration (MIC) value against tested bacterial strains ranging from 3.62±0.02mg/mLto60.0±0.32mg/mL.Citrus leaf oils were found to be more sensitive to Escherichia coli with MIC values ranged between 3.62±0.03 to 10.15±0.02 mg/mL. These essential oils also exhibited strong inhibitory potential against tested fungal strains, Aspergillus niger and Candida albicans, with MIC ranging from 3.22±0.02 to 28.17±0.04 mg/mL. Out of the five essential oils screened in this study, four of them have shown significant antimicrobial and antioxidant activities which can be attributed to synergistic potential of major monoterpenoid constituents present in these oils viz., geranial, neral, citronellal, nerol, geraniol, geranyl formate rather than the sesquiterpene dominated essential oil. Based on the findings obtained and conclusions derived, it is evident that the selected Citrus leaf essential oils are promising natural agents to fight free radical damage and antibiotic-resistant microbes.

Photoinduced force microscopy as a novel method for the study of microbial nanostructures.

A detailed comparison of the capabilities of electron microscopy and nano-infrared (IR) microscopy for imaging microbial nanostructures has been carried out for the first time. The surface sensitivity, chemical specificity, and non-destructive nature of spectroscopic mapping is shown to offer significant advantages over transmission electron microscopy (TEM) for the study of biological samples. As well as yielding important topographical information, the distribution of amides, lipids, and carbohydrates across cross-sections of bacterial (Escherichia coli, Staphylococcus aureus) and fungal (Candida albicans) cells was demonstrated using PiFM. The unique information derived from this new mode of spectroscopic mapping of the surface chemistry and biology of microbial cell walls and membranes, may provide new insights into fungal/bacterial cell function as well as having potential use in determining mechanisms of antimicrobial resistance, especially those targeting the cell wall.

Dectin-1/SYK Activation Induces Antimicrobial Peptide and Negative Regulator of NF-κB Signaling in Human Oral Epithelial Cells.

Oral epithelial cells serve as the primary defense against microbial exposure in the oral cavity, including the fungus Candida albicans. Dectin-1 is crucial for recognition of β-glucan in fungi. However, expression and function of Dectin-1 in oral epithelial cells remain unclear. We assessed Dectin-1 expression in Ca9-22 (gingiva), HSC-2 (mouth), HSC-3 (tongue), and HSC-4 (tongue) human oral epithelial cells using flow cytometry and real-time polymerase chain reaction. Cell treated with β-glucan-rich zymosan were evaluated using real-time polymerase chain reaction. Phosphorylation of spleen-associated tyrosine kinase (SYK) was analyzed by western blotting. Dectin-1 was expressed in all four cell types, with high expression in Ca9-22 and HSC-2. In Ca9-22 cells, exposure to β-glucan-rich zymosan did not alter the mRNA expression of chemokines nor of interleukin (IL)6, IL8, IL1β, IL17A, and IL17F. Zymosan induced the expression of antimicrobial peptides β-defensin-1 and LL-37, but not S100 calcium-binding protein A8 (S100A8) and S100A9. Furthermore, the expression of cylindromatosis (CYLD), a negative regulator of nuclear factor kappa B (NF-κB) signaling, was induced. In HSC-2 cells, zymosan induced the expression of IL17A. The expression of tumor necrosis factor alpha-induced protein 3 (TNFAIP3), a negative regulator of NF-κB signaling, was also induced. Expression of other cytokines and antimicrobial peptides remained unchanged. Zymosan induced phosphorylation of SYK in Ca9-22 cells, as well as NF-κB. Oral epithelial cells express Dectin-1 and recognize β-glucan, which activates SYK and induces the expression of antimicrobial peptides and negative regulators of NF-κB, potentially maintaining oral homeostasis.

Investigation of Antibacterial and Antifungal Efficacy of Zinc and Silver Nanoparticles Synthesized from Nasturtium officinale

Nanoparticles are nano-sized materials that can be widely used in fields such as medicine, pharmacology, and industry. The use of natural and easily available materials in nanoparticle synthesis is preferred because it is economical. Plants are extremely suitable for the synthesis of nanoparticles due to their natural and easy availability and the large number of components they contain with different properties. For this purpose, silver nanoparticles and zinc nanoparticles (AgNPs and ZnNPs), two different nanoparticles were synthesized from an edible plant, watercress (Nasturtium officinale). SEM (Scanning electron microscopy), SEM-EDX (Scanning electron microscopy-Energy dispersive X-ray), UV-VIS spectroscopy, XRD (X-ray crystallography), and FTIR (Fourier Transform Infrared Spectrophotometer) analyses of these nanoparticles were performed. In addition, the antimicrobial effects of these synthesized nanoparticles were determined by the disk diffusion method. As a result, nanoparticles obtained from Nasturtium officinale were effective on gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa), gram-positive bacteria (Staphylococcus aureus, Streptococcus pyogenes), and fungi (Candida albicans). In particular, AgNPs with broad-spectrum antimicrobial activity were obtained from the watercress. While ZnNPs showed inhibition effects of 49% on K. pneumoniae, 51% on S. aureus, and 62% on C. albicans, AgNPs showed inhibition effects of 93% on P. aeruginosa, 87% on S. aureus, 81% on E. coli, 80% on C. albicans, 72% on K. pneumoniae, and 56% on S. pyogenes. Thus, it has been shown that Nasturtium officinale can be used effectively in the production of new biotechnological products, especially with antimicrobial properties.

Function analysis and characterisation of a novel chitinase, MdCht9, in Musca domestica.

Insect chitinases have been proposed as potential targets for pest control. In this work, a novel group IV chitinase gene, MdCht9, from Musca domestica was found to have multiple functions in the physiological activity, including chitin regulation, development and antifungal immunity. The MdCht9 gene was cloned and sequenced, its phylogeny was analysed and its expression was determined in normal and 20E treated larvae. Subsequently, RNA interference (RNAi)-mediated MdCht9 knockdown was performed, followed by biochemical assays, morphological observations and transcriptome analysis. Finally, the recombinant protein MdCht9 (rMdCht9) was purified and tested for anti-microbial activity and enzyme characteristics. The results showed that MdCht9 consists of three domains, highly expressed in a larval salivary gland. RNAi silencing of MdCht9 resulted in significant down-regulation of chitin content and expression of 15 chitin-binding protein (CBP) genes, implying a new insight that MdCht9 might regulate chitin content by influencing the expression of CBPs. In addition, more than half of the lethality and partial wing deformity appeared due to the dsMdCht9 treatment. In addition, the rMdCht9 exhibited anti-microbial activity towards Candida albicans (fungus) but not towards Escherichia coli (G-) or Staphylococcus aureus (G+). Our work expands on previous studies of chitinase while providing a potential target for pest management.