Antimicrobial Activities of Different Fractions from Mucus of the Garden Snail Cornu aspersum

Achatina fulica haemocyanin-derived peptides as novel antimicrobial agents

Haemocyanin-derived peptides were previously found in semi-purified fractions of mucus secretion from the snail Achatina fulica, which exhibited an inhibitory effect on Staphylococcus aureus strains. Here, an in silico rational design strategy was employed to generate new antimicrobial peptides (AMPs) from A. fulica haemocyanin-derived peptides (AfH). The designed peptides were chemically synthetized using the Fmoc strategy, and their antimicrobial activity against Escherichia coli and S. aureus strains was evaluated using the broth microdilution method. In addition, the cytotoxic activity on Vero, HaCat, and human erythrocyte cells was also determined. The results demonstrated that 15-residue alpha-helical and cationic synthetic peptides exhibited the highest biological activity against Gram-positive strains, with minimum inhibitory concentrations (MIC) in the range from 7.5 to 30 μM. The positive selectivity index suggests a higher selectivity, primarily on the microorganisms evaluated, but not on eukaryotic cells. In this study, A. fulica hemocyanin was identified as an appropriate protein model for the rational design of AMPs against bacteria of public health significance. Further studies are required to evaluate the activity of the peptides on Gram-negative bacteria other than E. coli.

Synergistic Antibacterial Effect of Mucus Fraction from Cornu aspersum and Cirpofloxacin Against Pathogenic Bacteria Isolated from Wounds of Diabetic Patients

Background/Objectives: The treatment of diabetic foot ulcers (DFU) is a challenging medical problem of extreme clinical and social importance, as a consequence of the emerging antibiotic resistance and decreased quality of life of diabetic patients due to impaired wound healing. One of the current trends in world science is the search for biologically active substances derived from living organisms. Biologically active peptides from snail mucus attract considerable scientific interest because of their pleiotropic pharmacological properties. The aim of our study was to evaluate the activity of a combination between a snail mucus protein fraction (MW > 20 kDa) obtained from the garden snail Cornu aspersum and the clinically applied antibacterial chemotherapeutic ciprofloxacin on pathogenic bacterial strains isolated from DFU. Results: The test bacterial strains were characterized as multidrug resistant. The combination between ciprofloxacin and the snail mucus fraction of interest led to additive or synergistic effects depending on the test strain. The mucus fraction exerted a well-pronounced wound-healing effect and no cytotoxicity on normal human fibroblasts and keratinocytes. Methods: The snail mucus was obtained by a patented technology (BG Utility model 2097/2015) and its electrophoretic profile was presented by SDS-PAGE. The bacterial strains were identified and tested for antimicrobial susceptibility (BD Phoenix M50 and Kirby-Bauer assay). The in vitro cytotoxicity of the mucus was evaluated by ISO 10995-5. The antimicrobial activity and combination effects were tested through ISO 20776/1 and the Checkerboard assay. Conclusions: The obtained results are promising and open new horizons for the development of novel combination treatment schemas for healing of infected DFU.

Correction: Dolashki et al. Antimicrobial Activities of Different Fractions from Mucus of the Garden Snail Cornu aspersum. Biomedicines 2020, 8, 315

In the original publication [...].

The Role of Oxidative Stress in the Antifungal Activity of Two Mollusk Fractions on Resistant Fungal Strains

Fungal infections are a significant global public health challenge because of their widespread occurrence, morbidity, and profound social and economic consequences. Antifungal resistance is also an increasing concern, posing a substantial risk to public health. There is a growing interest in searching for new antifungal drugs isolated from natural sources. This study aimed to evaluate the antifungal activity of novel mollusk fractions against fungal strains resistant to nystatin and amphotericin B. In addition, the role of oxidative stress in the mechanism of damage was determined. The mucus from the garden snail Cornu aspersum (MCa/1-20) and the hemolymph fraction from the marine snail Rapana venosa (HLRv/3-100) were obtained and characterized via 12% sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and mass spectrometric -analyses. The results demonstrate that the spores and biomass of both mollusk fractions have a significant fungicidal effect against Penicillium griseofulvum, and Aspergillus niger. Compared to the control group, the release of intracellular proteins and reducing sugars was significantly increased in the treated groups. The data showed increased levels of oxidative stress biomarkers (lipid peroxidation and oxidatively damaged proteins) and a downregulated antioxidant enzyme defense, corresponding to increased antifungal activity. To our knowledge, this is the first study evaluating oxidative stress as a factor in mollusk fractions' antifungal activity.

Green Synthesis of Antibacterial CuO Nanoparticles Based on the Synergy Between Cornu aspersum Snail Mucus and Ascorbic Acid

Many biologically active compounds have been identified in the mucus of the garden snail Cornu aspersum, which are effective in the treatment of several diseases such as cancer, ulcers, wounds, etc. The incorporation of these compounds into the green synthesis of copper nanoparticles (CuONPs-Muc) was demonstrated in our previous study. Based on the synergistic effect of two reducing agents-C. aspersum snail mucus and ascorbic acid (AsA)-on CuSO4.5H2O, which also act as stabilizers of the resulting compound, a new method for the "green" synthesis of CuONPs-Muc is presented. Using two reducing agents has several advantages, such as forming spherical nanoparticles with a diameter of about 150 nm and reducing the formation time of CuONPs-Muc to 3 h. Analyses by ultraviolet-visible spectroscopy (UV-Vis) and Fourier transform infrared spectroscopy (FT-IR) show the formation of CuONPs-Muc, composed of a mixture of copper and copper oxide. This was confirmed by scanning electron microscopy combined with energy-dispersive spectroscopy (SEM/EDS) and X-ray diffraction (XRD). Another important advantage of CuONPs obtained by the new method with two reducing agents is the stronger inhibitory effect on the bacterial growth of some Gram-positive and Gram-negative bacterial strains, compared to CuONPs-Muc prepared with only one reducing agent, i.e., a fraction of mucus with an MW > 20 kDa.

Key Proteins in Rat Cerebral Cortex: Application of Cornu aspersum Extract as a Neuroprotective Agent in Alzheimer's Type Dementia

Alzheimer's disease (AD) is the most widespread neurodegenerative disorder. Recently, it was found that mucus extract from Cornu aspersum has beneficial effects on memory and cognitive processes in a rat scopolamine model of AD. The present study elucidated the mechanisms of action of standardized mucus snail extract (SE) enriched with a fraction above 20 kDa on Alzheimer-type dementia in rats. Using proteomic analysis on two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) on rat cortex extracts, we compared protein expression in both groups: the first group was treated intraperitoneally with scopolamine (Sco, 2 mg/kg, 11 days) and the second (Sco + SE) group was treated intraperitoneally with Sco (Sco, 2 mg/kg) and protected by SE (0.5 mL/100 g bw) applied daily orally for 11 days. Brain cortex was separated and the expressions of various proteins related to memory and cognitive functions were identified. We found that the expression of Ubiquitin carboxyl-terminal hydrolase isozyme L1, Calbindin, Vacuolar ATP synthase catalytic subunit A, Tropomyosin beta chain, 14-3-3 zeta/delta, Kinesin-1 heavy chain, and Stathmin-4 significantly differs in SE-protected rats as compared to dement animals treated only by Sco, and these brain proteins might be potential therapeutic targets for Alzheimer's-type dementia treatment.

Influence of the extraction method on functional properties of commercial snail secretion filtrates

Snail secretion is a complex mixture of several components, including proteins, glycoproteins, mucopolysaccharides and smaller molecules. Its growing use in nutraceutical, cosmetic and biomedical applications, as well as a component of edible and green packaging to replace chemical plasticizer, implies more affordable and sustainable extraction methods. We chose four extracts obtained from Cornu aspersum snails, different by origin, extraction medium (namely, citric acid, lactic acid or none) and additives and we performed a series of characterizations including the SDS-page, the measure of pH and density, the evaluation of dry matter and of protein content, supported by structural determinations by means of UV-visible and infrared spectroscopy, X-Rays diffraction and thermogravimetric measurements. Biological assays comprising evaluation of cytotoxicity and antibacterial activity were also carried out. All the tests were performed both on the as received snail filtrates and on the samples after proper dialysis to remove preservatives added by manufacturers. The obtained results put into evidence that the properties and composition of the final extract are strongly influenced by the collection method, that can be relevant for the proper use of snail filtrate in specific applications.

In silico and physico-chemical characterization of cluster formation dynamics in peptide solutions

Although antimicrobial peptides are considered one of the most promising alternatives to conventional antibiotics given the alarming increase in bacterial multidrug resistance, many aspects of their mechanism of action remain unclear, in particular the emergence and role of collective phenomena such as the spontaneous formation of nano-sized unstructured objects (clusters) and their effects on the biodynamics. We study this process using two novel peptides from the mucus of the garden snail Cornu aspersum as an example to reveal its dynamics and bioactivity implications through coordinated in silico and in vitro techniques - molecular dynamics simulations, UV-Vis and fluorescence spectroscopy, and antibacterial activity tests against two representative bacterial strains - one gram-negative (Escherichia coli 3458) and one gram-positive (Bacillus subtilis). The results obtained confirm the impact of the aggregation processes of the peptides on their biological activity and provide insight into possible synergies in their action.

Antibacterial Properties of Peptide and Protein Fractions from Cornu aspersum Mucus

The discovery and investigation of new natural compounds with antimicrobial activity are new potential strategies to reduce the spread of antimicrobial resistance. The presented study reveals, for the first time, the promising antibacterial potential of two fractions from Cornu aspersum mucus with an MW < 20 kDa and an MW > 20 kDa against five bacterial pathogens-Bacillus cereus 1085, Propionibacterium acnes 1897, Salmonella enterica 8691, Enterococcus faecalis 3915, and Enterococcus faecium 8754. Using de novo sequencing, 16 novel peptides with potential antibacterial activity were identified in a fraction with an MW < 20 kDa. Some bioactive compounds in a mucus fraction with an MW > 20 kDa were determined via a proteomic analysis on 12% sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and bioinformatics. High homology with proteins and glycoproteins was found, with potential antibacterial activity in mucus proteins named aspernin, hemocyanins, H-lectins, and L-amino acid oxidase-like protein, as well as mucins (mucin-5AC, mucin-5B, mucin-2, and mucin-17). We hypothesize that the synergy between the bioactive components determined in the composition of the fraction > 20 kDa are responsible for the high antibacterial activity against the tested pathogens in concentrations between 32 and 128 µg/mL, which is comparable to vancomycin, but without cytotoxic effects on model eukaryotic cells of Saccharomyces cerevisiae. Additionally, a positive effect, by reducing the levels of intracellular oxidative damage and increasing antioxidant capacity, on S. cerevisiae cells was found for both mucus extract fractions of C. aspersum. These findings may serve as a basis for further studies to develop a new antibacterial agent preventing the development of antibiotic resistance.

Development of CuO Nanoparticles from the Mucus of Garden Snail Cornu aspersum as New Antimicrobial Agents

Several biologically active compounds involved in the green synthesis of silver and gold nanoparticles have been isolated from snail mucus and characterized. This paper presents a successful method for the application of snail mucus from Cornu aspersum as a bioreducing agent of copper sulfate and as a biostabilizer of the copper oxide nanoparticles (CuONPs-Muc) obtained. The synthesis at room temperature and neutral pH yielded nanoparticles with a spherical shape and an average diameter of 150 nm. The structure and properties of CuONPs-Muc were characterized using various methods and techniques, such as ultraviolet-visible spectroscopy (UV-vis), high-performance liquid chromatography (HPLC), one-dimensional polyacrylamide gel electrophoresis (1D-PAGE), up-conversion infrared spectroscopy Fourier transform (FTIR), scanning electron microscopy combined with energy dispersive spectroscopy (SEM/EDS), Raman spectroscopy and imaging, thermogravimetric analysis (TG-DSC), etc. Mucus proteins with molecular weights of 30.691 kDa and 26.549 kDa were identified, which are involved in the biogenic production of CuONPs-Muc. The macromolecular shell of proteins formed around the copper ions contributes to a higher efficiency of the synthesized CuONPs-Muc in inhibiting the bacterial growth of several Gram-positive (Bacillus subtilis NBIMCC2353, Bacillus spizizenii ATCC 6633, Staphylococcus aureus ATCC 6538, Listeria innocua NBIMCC8755) and Gram-negative (Escherichia coli ATCC8739, Salmonella enteitidis NBIMCC8691, Salmonella typhimurium ATCC 14028, Stenotrophomonas maltophilia ATCC 17666) bacteria compared to baseline mucus. The bioorganic synthesis of snail mucus presented here provides CuONPs-Muc with a highly pronounced antimicrobial effect. These results will expand knowledge in the field of natural nanomaterials and their role in emerging dosage forms.

Snail extract for skin: A review of uses, projections, and limitations

BACKGROUND

Snail mucin is becoming increasingly popular for its wide range of ingredients and potential benefits. Snail extract's widespread appearance in cosmetic formulations encourages an investigation into the medical and cosmetic benefits.

AIMS

This study aims to explore current literature on the variety of snail mucin applications. Specifically, we present a review of the uses, global market estimates and projects, and limitations to snail mucin.

METHODS

A literature search was conducted on PubMed reviewing snail mucin and their application in medical and dermatologic fields examining their uses. Economic reports were also investigated for Global Market estimates.

RESULTS

The therapeutic use of snail mucin in medical fields has been studied as antimicrobial agents, drug delivery vehicles, antitumor agents, wound healing agents, and biomaterial coatings among others. Additionally, the use in cosmetic fields includes antiaging, hydrating, anti-acne, scarring, and hyperpigmentation treatments. It is important to highlight that most studies conducted were preclinical or small clinical studies, stressing the need for additional large-scale clinical trials to support these claims. Investigations into the global market found estimates ranging from $457 million to $1.2 billion with upward projections in the upcoming decade. Limitations include ethical habitats for collection, allergy investigation, and missing clinical studies.

CONCLUSIONS

The findings presented here emphasize the expanding uses of snail mucin and its ingredients alongside a growing market cosmetic industry should consider. We also emphasize the need for appropriate clinical trials into the stated benefits of snail mucin to ensure consumer safety and ethical extraction of mucin.

Cryptomphalus aspersa Egg Extract Protects against Human Stem Cell Stress-Induced Premature Senescence

Cellular senescence is a tightly regulated pathophysiologic process and is caused by replicative exhaustion or external stressors. Since naturally derived bioactive compounds with anti-ageing properties have recently captured scientific interest, we analysed the anti-ageing and antioxidant efficacy of Cryptomphalus aspersa egg extract (CAEE). Its effects on stemness, wound-healing properties, antioxidant defense mechanisms, and DNA damage repair ability of Human Wharton's jelly mesenchymal stem cells (WJ-MSCs) were analysed. Our results revealed that CAEE fortifies WJ-MSCs stemness, which possibly ameliorates their wound-healing ability. Additionally, we show that CAEE possesses a strong antioxidant capacity as demonstrated by the elevation of the levels of the basic antioxidant molecule, GSH, and the induction of the NRF2, a major antioxidant regulator. In addition, CAEE alleviated cells' oxidative stress and therefore prevented stress-induced premature senescence (SIPS). Furthermore, we demonstrated that the prevention of SIPS could be mediated via the extract's ability to induce autophagy, as indicated by the elevation of the protein levels of all basic autophagic molecules and the increase in formation of autophagolysosomes in CAEE-treated WJ-MSCs. Moreover, CAEE-treated cells exhibited decreased Caveolin-1 levels. We propose that Cryptomphalus aspersa egg extract comprises bioactive compounds that can demonstrate strong antioxidant/anti-ageing effects by regulating the Caveolin-1-autophagy-senescence molecular axis.

Extraction, structure, pharmacological activities and applications of polysaccharides and proteins isolated from snail mucus

Snail mucus had medical applications for wound healing as early as ancient Greece and the late Han Dynasty (China). A literature search found 165 modern research papers discussing the extraction methods, chemical compositions, pharmacological activities, and applications of snail mucus. Thus, this review summarized the research progress on the extraction, structure, pharmacological activities, and applications of polysaccharides and proteins isolated from snail mucus. The extraction methods of snail mucus include natural secretion and stimulation with blunt force, spray, electricity, un-shelling, ultrasonic-assisted, and ozone-assisted. As a natural product, snail mucus mainly comprises two polysaccharides (glycosaminoglycan, dextran), seven glycoproteins (mucin, lectin), various antibacterial peptides, allantoin, glycolic acid, etc. It has pharmacological activities that encourage cell migration and proliferation, and promote angiogenesis and have antibacterial, anti-oxidative and anticancer properties. The mechanism of snail mucus' chemicals performing antibacterial and wound-healing was proposed. Snail mucus is a promising bioactive product with multiple medical applications and has great potential in the pharmaceutical and healthcare industries. Therefore, this review provides a valuable reference for researching and developing snail mucus.

Antibacterial Action of Protein Fraction Isolated from Rapana venosa Hemolymph against Escherichia coli NBIMCC 8785

Natural products and especially those from marine organisms are being intensively explored as an alternative to synthetic antibiotics. However, the exact mechanisms of their action are not yet well understood. The molecular masses of components in the hemolymph fraction with MW 50-100 kDa from Rapana venosa were determined using ImageQuant™ TL v8.2.0 software based on electrophoretic analysis. Mainly, three types of compounds with antibacterial potential were identified, namely proteins with MW at 50.230 kDa, 62.100 kDa and 93.088 kDa that were homologous to peroxidase-like protein, aplicyanin A and L-amino acid oxidase and functional units with MW 50 kDa from R. venous hemocyanin. Data for their antibacterial effect on Escherichia coli NBIMCC 8785 were obtained by CTC/DAPI-based fluorescent analysis (analysis based on the use of a functional fluorescence probe). The fluorescent analyses demonstrated that a 50% concentration of the fraction with MW 50-100 kDa was able to eliminate 99% of the live bacteria. The antimicrobial effect was detectable even at a 1% concentration of the active compounds. The bacteria in this case had reduced metabolic activity and a 24% decreased size. The fraction had superior action compared with another mollusc product-snail slime-which killed 60% of the E. coli NBIMCC 8785 cells at a 50% concentration and had no effect at a 1% concentration. The obtained results demonstrate the high potential of the fraction with MW 50-100 kDa from R. venosa to eliminate and suppress the development of Escherichia coli NBIMCC 8785 bacteria and could be applied as an appropriate component of therapeutics with the potential to replace antibiotics to avoid the development of antibiotic resistance.

Assessment of the In Vitro and In Vivo Antitumor Activity of Hemocyanins from Helix aspersa, Helix lucorum, and Rapana venosa in a Graffi Myeloid Tumor Model

Hemocyanins are oxygen-transporting glycoproteins in the hemolymph of some invertebrate species that attracted scientific interest as potential anticancer agents. The present study aims to assess the in vitro and in vivo anticancer activity of hemocyanins isolated from Helix aspersa, Helix lucorum, and Rapana venosa in the Graffi myeloid tumor model. The in vitro antitumor activity of the hemocyanins was determined by a MTT test and cytomorphological analysis by fluorescent and transmission electron microscopy. The in vivo effects of the hemocyanins were examined in hamsters transplanted with Graffi tumor. The serum antibody titers against the tested hemocyanins and tumor antigen were determined by ELISA. Histopathological assessment of the morphological features related to antitumor effect, immune system response, and toxicity in some internal organs was performed. The results of in vitro studies indicated that the tested hemocyanins induced significant antiproliferative and apoptogenic effects. The in vivo investigations demonstrated a protective antitumor effect, expressed in reduced transplantability, suppression of tumor growth and metastasis, reduced mortality, prolonged survival time, and absence of toxic side effects. The present study indicated that the antitumor activity of the studied hemocyanins was due to both immune stimulation and direct effects on the tumor cells, and they displayed their potential as therapeutic agents against hematological malignances.

Snail Mucus Protective Effect on Ethanol-Induced Gastric Ulcers in Mice

Nowadays, an increased interest in natural compounds with preventive or therapeutic potential for various diseases has been observed. Given the involvement of oxidative stress in the pathogenesis of gastric ulcer (GU) and the wide range of bioactive compounds isolated from snails, this study aimed to investigate the protective effect of Cornu aspersum (Müller, 1774) mucus on ethanol-induced GUs. Male albino mice were divided into Control, Ethanol, Mucus + Ethanol and Mucus + Omeprazole treated groups. The GUs were induced by administration of 96% ethanol (10 mL/kg, per os). One hour before ulcer induction, the mice of Mucus + Ethanol group were pretreated with mucus (20 mg/kg, per os), and the mice of Mucus + Omeprazole group were pretreated with omeprazole (20 mg/kg, per os). Ethanol administration caused grave lesions of gastric mucosa and a significant decrease of glutathione (GSH) and superoxide dismutase (SOD), catalase, and glutathione reductase (GR) activities. In the animals with mucus or omeprazole pre-administration compared to the Ethanol group, the following were observed: only a small number of hemorrhagic fields, significantly reduced GU index with calculated 73% protection by mucus and 78% protection by omeprazole, and significant recovery of mucosal GSH and SOD and GR activities. In addition, the mucus inhibited Helicobacter pylori growth. Thus, the protective effect of C. aspersum mucus on both gastric mucosa and gastric antioxidant potential in ethanol-induced GU model suggests that it may serve as a good tool for prevention of this disease.

Beneficial Effects of Snail Helix aspersa Extract in an Experimental Model of Alzheimer’s Type Dementia

Background: Alzheimer’s disease (AD) is a complex neurodegenerative disease with multifactorial etiology, unsatisfactory treatment, and a necessity for broad-spectrum active substances for cure. The mucus from Helix aspersa snail is a mixture of bioactive molecules with antimicrobial, anti-inflammatory, antioxidant, and anti-apoptotic effects. So far there are no data concerning the capacity of snail extract (SE) to affect neurodegenerative disorders. Objective: The effects of SE from Helix aspersa on learning and memory deficits in Alzheimer’s type dementia (ATD) induced by scopolamine (Sco) in male Wistar rats were examined and some mechanisms of action underlying these effects were evaluated. Methods: SE (0.5 mL/100 g) was applied orally through a food tube for 16 consecutive days: 5 days before and 11 days simultaneously with Sco (2 mg/kg, intraperitoneally). At the end of Sco treatment, using behavioral methods, we evaluated memory performance. Additionally, in cortex and hippocampus the acetylcholinesterase (AChE) activity, acetylcholine and monoamines (dopamine, noradrenaline, and serotonin) content, levels of main oxidative stress markers, and expression of brain-derived neurotrophic factor (BDNF) and cAMP response element-binding protein (CREB) were determined. Results: We demonstrated that, according to all behavioral tests used, SE significantly improved the cognitive deficits induced by Sco. Furthermore, SE possessed AChE inhibitory activity, moderate antioxidant properties and the ability to modulate monoamines content in two brain structures. Moreover, multiple SE applications not only restored the depressed by Sco expression of CREB and BDNF, but significantly upregulated it. Conclusion: Summarizing results, we conclude that complex mechanisms underlie the beneficial effects of SE on impaired memory in Alzheimer’s type dementia.

Effect and Mechanisms of Antibacterial Peptide Fraction from Mucus of C. aspersum against Escherichia coli NBIMCC 8785

Peptides isolated from the mucus of Cornu aspersum could be prototypes for antibiotics against pathogenic bacteria. Information regarding the mechanisms, effective concentration, and methods of application is an important tool for therapeutic, financial, and ecological regulation and a holistic approach to medical treatment. A peptide fraction with MW < 10 kDa was analyzed by MALDI-TOF-TOF using Autoflex™ III. The strain Escherichia coli NBIMCC 8785 (18 h and 48 h culture) was used. The changes in bacterial structure and metabolic activity were investigated by SEM, fluorescent, and digital image analysis. This peptide fraction had high inhibitory effects in surface and deep inoculations of E. coli of 1990.00 and 136.13 mm2/mgPr/µMol, respectively, in the samples. Thus, it would be effective in the treatment of infections involving bacterial biofilms and homogenous cells. Various deformations of the bacteria and inhibition of its metabolism were discovered and illustrated. The data on the mechanisms of impact of the peptides permitted the formulation of an algorithm for the treatment of infections depending on the phase of their development. The decrease in the therapeutic concentrations will be more sparing to the environment and will lead to a decrease in the cost of the treatment.

Microbial diversity of garden snail mucus

The search for new natural compounds for application in medicine and cosmetics is a trend in biotechnology. One of the sources of such active compounds is the snail mucus. Snail physiology and the biological activity of their fluids (especially the mucus) are still poorly studied. Only a few previous studies explored the relationship between snails and their microbiome. The present study was focused on the biodiversity of the snail mucus used in the creation of cosmetic products, therapeutics, and nutraceuticals. The commonly used cultivation techniques were applied for the determination of the number of major bacterial groups. Fluorescence in situ hybridization for key taxa was performed. The obtained images were subjected to digital image analysis. Sequencing of the 16S rRNA gene was also done. The results showed that the mucus harbors a rich bacterial community (10.78 × 1010  CFU/ml). Among the dominant bacteria, some are known for their ability to metabolize complex polysaccharides or are usually found in soil and plants (Rhizobiaceae, Shewanella, Pedobacter, Acinetobacter, Alcaligenes). The obtained data demonstrated that the snail mucus creates a unique environment for the development of the microbial community that differs from other parts of the animal and which resulted from the combined contribution of the microbiomes derived from the soil, plants, and the snails.

Antibacterial, Antibiofilm and Anti-Virulence Activity of Biactive Fractions from Mucus Secretion of Giant African Snail Achatina fulica against Staphylococcus aureus Strains

Staphylococcus aureus is an important etiological agent that causes skin infections, and has the propensity to form biofilms, leading to significant mortality and morbidity in patients with wounds. Mucus secretion from the Giant African snail Achatina fulica is a potential source of biologically active substances that might be an important source for new drugs to treat resistant and biofilm-forming bacteria such as S. aureus. This study evaluated the effect of semi-purified fractions from the mucus secretion of A. fulica on the growth, biofilm formation and virulence factors of S. aureus. Two fractions: FMA30 (Mw >30 kDa) and FME30 (Mw 30−10 kDa) exhibited antimicrobial activity against S. aureus with a MIC₅₀ of 25 and 125 µg/mL, respectively. An inhibition of biofilm formation higher than 80% was observed at 9 µg/mL with FMA30 and 120 µg/mL with FME30. Furthermore, inhibition of hemolytic and protease activity was determined using a concentration of MIC₂₀, and FME30 showed a strong inhibitory effect in the formation of clots. We report for the first time the effect of semi-purified fractions of mucus secretion of A. fulica on biofilm formation and activity of virulence factors such as α-hemolysin, coagulase and proteases produced by S. aureus strains.

Antimicrobial Efficiency of Aloe arborescens and Aloe barbadensis Natural and Commercial Products

Nowadays, there are many commercial products from natural resources on the market, but they still have many additives to increase their biological activities. On the other hand, there is particular interest in natural sources that would have antimicrobial properties themselves and would inhibit the growth and the reproduction of opportunistic microorganisms. Therefore, a comparative antimicrobial study of natural samples of aloe and its commercial products was performed. Qualitative and quantitative determination of antimicrobial efficiency of Aloe arborescens and Aloe barbadensis and its commercial products on fungi, Gram-negative, and Gram-positive bacteria was performed. Samples exhibited antimicrobial activity and slowed down the growth of all tested microorganisms. Research has shown that natural juices and gels of A. arborescens and A. barbadensis are at higher added concentrations comparable to commercial aloe products, especially against microbial cultures of Bacillus cereus, Candida albicans, and Pseudomonas aeruginosa, whose growths were completely inhibited at a microbial concentration of 600 μg/mL. Of particular importance are the findings of the good antimicrobial efficacy of fresh juice and gel of A. arborescens on tested microorganisms, which is less known and less researched. These results show great potential of A. arborescens for further use in medicine, cosmetics, food, and pharmaceutical industries.