Bacteriostatic and bactericidal clays: an overview

Mud matters: exploring the quality and composition of Estonia's curative mud deposits

The study focuses on the current state of curative mud deposits in Estonia as of 2022, examining changes over the past decade and providing essential information on curative mud quality. Total of 64 curative mud samples were collected in 2022, marking the first investigation into hazardous substances such as phenols, petroleum products, and pesticides. The study encompassed analyses of organic and mineral matter content, grain size, microbiology, and heavy metal concentrations, totalling 1649 measurements. Comparisons with previous data revealed stable organic matter concentrations in lake and marine sediments over the last decade. Microbiological contamination in curative mud samples was relatively low, indicating cleanliness. Petroleum product concentrations varied, with Haapsalu at 42 mg/kg, Värska at 118.6 mg/kg, and Käina below the limit of quantification. Phenol concentrations were generally below the limit of quantification, except for Värska. Pesticides were found in Värska samples, but in other sediments, levels were below the limit of quantification. Average heavy metal concentrations in curative mud decreased between 2013-2014 and 2022, remaining below the target value. The study's results are crucial for curative mud-related entrepreneurship in Estonia, facilitating compliance with the new regulatory standards. The comprehensive data obtained will contribute to the consistency and efficacy of curative mud-related practices in the country.

Antibacterial and therapeutic potential of historic deposits of silesian healing clay - terra sigillataSilesiaca

ETHNOPHARMACOLOGICAL RELEVANCE

The increasing evolution of pathogen resistance is a global problem that requires novel solutions. Recently, an increased interest in ethnomedicinal sources can be observed in the derivation of new medicines. The return to traditional medicinal formulations handed down for generations is being followed, but it is necessary to revise them again, taking into account the generally accepted research protocol.

AIM OF THE STUDY

We aimed to evaluate the antimicrobial potential of historical deposits of Silesian healing clay (SHC), used in ethnomedicine against Gram-positive bacteria and to assess their biological activity using a primary dermal fibroblast line (NHDF) and a model monocyte line (THP1).

MATERIALS AND METHODS

Information on medicinal clay deposits that occur in Silesia and are traditionally used in ethnomedicine or ancient medicine and known as terra sigillata Silesiaca or SHC, was selected on available source materials and old prints and maps from the archives of the Polish Geological Institute (Wrocław, Poland). Subsequently, their places of occurrence were identified and traced in the field by taking three deposits from the Silesia territory: Upper Silesia (D1), Opole Silesia (D2), and Lower Silesian (D3) Voivodeships for analysis. Their basic parameters and antimicrobial efficacy against pathogenic bacteria, Gram-positive streptococci and staphylococci, including methicillin-resistant strains, were examined. The study evaluated the effects of clays on growth and vitality using a primary dermal fibroblast line (NHDF) and a monocytic line (THP1). Studies were performed on a cell culture model to determine the effects on tissue regeneration (fibroblasts) and anti-inflammatory effects (monocytes). The study attempted to identify the mechanism of antimicrobial action, especially the textural characteristics and geochemical composition, as well as the environmental reaction (pH).

RESULTS

SHCs were classified into the following textural classes: clay loam (D1), clay (D2), and sand (D3). The tested deposits have antimicrobial properties that reduce the bacterial population (104 CFU) compared to the control (108 CFU). The antimicrobial effect depends on the type of clay and the species or strain of bacteria used. In-house studies clearly showed that Staphylococcus aureus Pcm 2054 and Staphylococcus epidermidis MRSE ATCC 2538 cells were completely adsorbed by clay minerals from clay D3.13. Furthermore, 10% leachates also showed an antimicrobial effect, as a reduction in bacterial populations was observed ranging from 91 to 100%. The results showed stimulation of fibroblast culture proliferation and inhibition of the growth of inflammatory cells (monocytes).

CONCLUSION

SHCs tested have antimicrobial potential, in particular D2.7, D2.11, and D3.13. The D3.13 deposit had a bactericidal effect against the staphylococci tested. Aqueous solutions of clays also showed bacteriostatic effect. The results obtained in cell culture model tests indicate properties that modulate the healing process - stimulation of fibroblast growth (NHDF line) and inhibition of monocyte growth (THP1 line).

Recent advances and perspectives for intercalation layered compounds. Part 2: applications in the field of catalysis, environment and health

Intercalation compounds represent a unique class of materials that can be anisotropic (1D and 2D-based topology) or isotropic (3D) through their guest/host superlattice repetitive organisation. Intercalation refers to the reversible introduction of guest species with variable natures into a crystalline host lattice. Different host lattice structures have been used for the preparation of intercalation compounds, and many examples are produced by exploiting the flexibility and the ability of 2D-based hosts to accommodate different guest species, ranging from ions to complex molecules. This reaction is then carried out to allow systematic control and fine tuning of the final properties of the derived compounds, thus allowing them to be used for various applications. This review mainly focuses on the recent applications of intercalation layered compounds (ILCs) based on layered clays, zirconium phosphates, layered double hydroxides and graphene as heterogeneous catalysts, for environmental and health purposes, aiming at collecting and discussing how intercalation processes can be exploited for the selected applications.

VMT/ACP/Dextran composite nanosheets against dental caries through promoting mineralization of dentin tubules, pH buffering, and antibacterial

Dental caries is a worldwide public healthcare concern, and is closely related to the acidic environment that caused by bacterial decomposition of food. In this study, a two-step ion exchange liquid-phase stripping method was applied to strip out vermiculite (VMT) nanosheets, then amorphous calcium phosphate (ACP) and dextran were inserted between the VMT nanosheets interlayer to obtain a composite two-dimension nanosheets (VMT/ACP/Dextran). VMT/ACP/Dextran composite nanosheets exhibited excellent biocompatibility and could provide exogenous Ca2+and PO43- from ACP, provide SiO44-, Mg2+, Fe2+ and obtain buffering pH and antibacterial properties from VMT, as well as improve suspension stability and targeting Streptococcus mutans through glucan. The in vitro study showed that the composite materials could promote the mineralization and sealing of dentin tubules by releasing active ions, buffer pH 4.5 (a value close to the pH in the dental plaque environment) to pH 6.6-7.1 (values close to the pH in human saliva) through ion exchange, and exert antibacterial effects by targeting Streptococcus mutans and exerting oxidase like and peroxidase like activities to produce reactive oxygen species (ROS). The in vivo animal study showed that daily cleaning teeth using VMT/ACP/Dextran composite nanosheets could effectively reduce the incidence rate and severity of dental caries in rats. Taking together, the developed VMT/ACP/Dextran composite nanosheets, which integrated the excellent properties of VMT, ACP and dextran, can effectively prevent dental caries through a combination of factors such as buffering acids, antibacterial properties, and promoting calcification, and may be used as an active ingredient for daily oral hygiene or filling materials to prevent and treat dental caries.

Reciprocal Interactions of Abiotic and Biotic Dechlorination of Chloroethenes in Soil

Chloroethenes (CEs) as common organic pollutants in soil could be attenuated via abiotic and biotic dechlorination. Nonetheless, information on the key catalyzing matter and their reciprocal interactions remains scarce. In this study, FeS was identified as a major catalyzing matter in soil for the abiotic dechlorination of CEs, and acetylene could be employed as an indicator of the FeS-mediated abiotic CE-dechlorination. Organohalide-respiring bacteria (OHRB)-mediated dechlorination enhanced abiotic CEs-to-acetylene potential by providing dichloroethenes (DCEs) and trichloroethene (TCE) since chlorination extent determined CEs-to-acetylene potential with an order of trans-DCE > cis-DCE > TCE > tetrachloroethene/PCE. In contrast, FeS was shown to inhibit OHRB-mediated dechlorination, inhibition of which could be alleviated by the addition of soil humic substances. Moreover, sulfate-reducing bacteria and fermenting microorganisms affected FeS-mediated abiotic dechlorination by re-generation of FeS and providing short chain fatty acids, respectively. A new scenario was proposed to elucidate major abiotic and biotic processes and their reciprocal interactions in determining the fate of CEs in soil. Our results may guide the sustainable management of CE-contaminated sites by providing insights into interactions of the abiotic and biotic dechlorination in soil.

Construction of nano slow-release systems for antibacterial active substances and its applications: A comprehensive review

At present, nano-carrier materials with antibacterial activity are of great significance. Due to the widespread resistance of many pathogenic microorganisms, it has seriously threatened human health. The natural antimicrobial substances extracted from fruits and vegetables can significantly improve their stability combined with nano-carrier materials. The resistance of pathogenic microorganisms will be substantially reduced, greatly enhancing the effect of active antimicrobial substances. Nanotechnology has excellent research prospects in the food industry, antibacterial preservation, food additives, food packaging, and other fields. This paper introduces nano-carrier materials and preparation techniques for loading and encapsulating active antibacterial substances in detail by constructing a nano-release system for active antibacterial substances. The antibacterial effect can be achieved by protecting them from adverse external conditions and destroying the membrane of pathogenic microorganisms. The mechanism of the slow release of the bacteriostatic active substance is also described. The mechanism of carrier loading and release is mainly through non-covalent forces between the bacteriostatic active substance and the carrier material, such as hydrogen bonding, π-π stacking, van der Waals forces, electrostatic interactions, etc., as well as the loading and adsorption of the bacteriostatic active substance by the chemical assembly. Finally, its wide application in food and medicine is introduced. It is hoped to provide a theoretical basis and technical support for the efficient utilization and product development of bacteriostatic active substances.

[Microbiome of therapeutic muds used in Tatarstan]

Therapeutic muds (peloids), which are widely used for body healing, improve metabolism and have antibacterial, anti-inflammatory and analgesic effects due to enrichment with necessary microelements and biological active substances. However, the microbiological component of these effects is not well studied.

OBJECTIVE

To characterize the microbiome of therapeutic muds, used in the Tatarstan Republic, by identifying spectrum of cultivated microorganisms, using molecular analysis of bacterial communities, and by determining their biodiversity and functional potential based on revealed genetic determinants.

MATERIAL AND METHODS

The study design of 5 peloids samples (local sapropels and peat deposits of swamp; 3 samples of Crimean sulfide muds) included three main techniques: isolation and taxonomic determination of cultivated microorganisms by time-of-flight mass-spectrometry; molecular analysis of peloids bacterial communities by 16S RNA high-throughput sequencing; identification of functional profiles of communities by their genetic determinant using Global Mapper tool on iVikodak platform.

RESULTS

Experimental studies have confirmed the safety of examined peloids, where non-pathogenic cultivated bacteria belonging mainly to Bacillus and Rhodococcus genera were dominant. Metagenomic analysis showed that Firmicutes, Proteobacteria and Actinobacteria were predominant in all samples in different ratios. It has been established, that there is both the internal biodiversity of each sample and difference between them. The functional profile of microbial communities was determined based on the identification of bacterial genes. It has been revealed that all communities have an ability to synthesize antibiotics, as well as to decompose dangerous xenobiotics - polyaromatic hydrocarbons, cyclic compounds, and dioxins.

CONCLUSION

Various microbial communities, which were identified in the therapeutic muds, contribute both to the clearance of toxicants in the peloids and to the antibacterial properties of the latter. The obtained priority results create a fundamental basis for the subsequent study of the role of peloids' microbiome of different origin in their healing action.

The mechanism of metal-based antibacterial materials and the progress of food packaging applications: A review

Food packages have been detected carrying novel coronavirus in multi-locations since the outbreak of COVID-19, causing major concern in the field of food safety. Metal-based supported materials are widely used for sterilization due to their excellent antibacterial properties as well as low biological resistance. As the principal part of antibacterial materials, the active component, commonly referred to Ag, Cu, Zn, etc., plays the main role in inhibiting and killing pathogenic microorganisms by destroying the structure of cells. As another composition of metal-based antibacterial materials, the carrier could support and disperse the active component, which on one hand, could effectively decrease the usage amount of active component, on the other hand, could be processed into various forms to broaden the application range of antibacterial materials. Different from other metal-based antibacterial reviews, in order to highlight the detailed function of various carriers, we divided the carriers into biocompatible and adsorptable types and discussed their different antibacterial effects. Moreover, a novel substitution antibacterial mechanism was proposed. The coating and shaping techniques of metal-based antibacterial materials as well as their applications in food storage at ambient and low temperatures are also comprehensively summarized. This review aims to provide a theoretical basis and reference for researchers in this field to develop new metal-based antibacterial materials.

The role of soils in provision of genetic, medicinal and biochemical resources

Intact, 'healthy' soils provide indispensable ecosystem services that largely depend on the biotic activity. Soil health is connected with human health, yet, knowledge of the underlying soil functioning remains incomplete. This review highlights selected services, i.e. (i) soil as a genetic resource and hotspot of biodiversity, forming the basis for providing (ii) biochemical resources and (iii) medicinal services and goods. Soils harbour an unrivalled biodiversity of organisms, especially microorganisms. Some of the abilities of autochthonous microorganisms and their relevant enzymes serve (i) to improve natural soil functions and in particular plant growth, e.g. through beneficial plant growth-promoting, symbiotic and mycorrhizal microorganisms, (ii) to act as biopesticides, (iii) to facilitate biodegradation of pollutants for soil bioremediation and (iv) to yield enzymes or chemicals for industrial use. Soils also exert direct effects on human health. Contact with soil enriches the human microbiome, affords protection against allergies and promotes emotional well-being. Medicinally relevant are soil substrates such as loams, clays and various minerals with curative effects as well as pharmaceutically active organic chemicals like antibiotics that are formed by soil microorganisms. By contrast, irritating minerals, soil dust inhalation and misguided soil ingestion may adversely affect humans. This article is part of the theme issue 'The role of soils in delivering Nature's Contributions to People.

Peloids as Thermotherapeutic Agents

The use of peloids as heat-providing therapeutic systems dates back to antiquity. Such systems consist of a liquid phase and an organic or inorganic solid phase. The latter facilitates the handling, preparation and stability of the solid–liquid system, modifying its organoleptic and phy-sicochemical properties, and improves its efficacy and tolerance. Peloids enable the application of heat to very specific zones and the release of heat at a given rate. The aims of this work are to study 16 reference peloids used in medical spa centers as thermo-therapeutic agents as well as to propose nine raw materials as a solid phase for the preparation of peloids. The physical properties studied are the centesimal composition, the instrumental texture and the thermal parameters. In conclusion, the peloids of the medical spas studied are used as thermotherapeutic agents in the treatment of musculoskeletal disorders, especially in knee osteoarthritis and to a lesser extent in back pain and psoriatic arthropathy. The clinical experience in these centers shows that the main effects of the application of their peloids are the reduction of pain, an increase in the joint’s functional capacity and an improvement in the quality of life. As thermotherapeutic agents, all the peloids of the me-dical spas studied and the pastes (raw materials with distilled water) examined showed a heat flow rate of up to four times lower than that shown by the same amount of water. The raw materials studied can be used as solid phases for the preparation of peloids with mineral waters.

Chemical and mineralogical characteristics of peloids in Turkey

To investigate the physical, chemical, and mineralogical characteristics of peloids, which are being used traditionally and historically across Turkey, and evaluate their suitability and potential for use in peloidotherapy. Five peloid samples were gathered from their places of origin, namely Gölemezli, Dalyan, Köprüköy, Gökçeada, and Dikili. Mineral analysis and physical and chemical analyses including electrical conductivity, density, cations, anions, trace elements, organic matters, and water retention capacity at 105 °C were performed. The peloids contained a combination of clay minerals (mainly montmorillonite, kaolinite, and muscovite) and non-clay minerals (mainly quartz, calcite, dolomite, and albite) except for Gölemezli peloid, which was dominated by calcite. The other minerals (i.e., chloride-serpentine, sphalerite, pyrite, magnesium calcite, cristobalite) were also found in some peloids. Gölemezli, Dalyan, and Köprüköy peloids had high total organic matters, mainly humic substances. The water retention capacity was high in Dalyan, Köprüköy, and Dikili peloids. All peloids had a pH value slightly greater than 7 (range 7.93-8.69). Dalyan, Köprüköy, and Dikili peloids had a high water retention capacity. Dalyan and Gökçeada peloids had a high electrical conductivity, 22.040 and 9.020 μS/cm, respectively. The density of peloids was ranged between 1.240 (Gölemezli) and 1.450 (Gökçeada) g/cm³. Total mineralization of investigated peloids was greater than 1000 mg/L: Köprüköy, 2754.8 mg/L; Gölemezli, 3092.8 mg/L; Dikili, 4044.6 mg/L; Gökçeada, 6576.6 mg/L; and Dalyan, 11782.9 mg/L, mainly sodium, magnesium, calcium, chloride, sulfate, bicarbonate, and metasilicic acid. The levels of trace elements were low (≤ 2.0 mg/L) in all peloids. The peloids contained various amounts of clay minerals (mainly montmorillonite, kaolinite, and muscovite), non-clay minerals (mainly quartz, calcite, dolomite, and albite), organic matters (mainly humic acid), cations (mainly sodium, magnesium, and calcium), anions (mainly chloride, sulfate, and bicarbonate), and insoluble compounds (mainly metasilicic acid). The physical, chemical, and mineralogical properties of peloids suggest their suitability and potential for use in peloidotherapeutic applications.

Mud therapy and rehabilitation - scientific relevance in the last six years (2015 – 2020) Systematic literature review and meta-analysis based on the PRISMA paradigm

Abstract Background. Balneotherapy is a stimulation - adaptation treatment method applied in the forms of bathing, drinking, and inhalation cures performed with natural therapeutic factors, a method which is acting in three main ways: thermally, mechanically, and chemically. Mud or peloids are natural therapeutic factors formed by natural processes under the influence of biological and geological phenomena, which in a finely dissolved state and mixed with water (mud) are used in medical practice in the form of baths or local procedures. Objective. This systematic review aims to rigorously select related articles and identify within their content, the main possible uses of therapeutic mud and physiological mechanisms, to see the main region of scientific interest for pelotherapy, and to discuss the value of mud therapy in rehabilitation medicine. Methods. The working method is based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We searched for open-access articles published in English, between January 2015 and December 2020, from the following databases: Cochrane, Elsevier, NCBI/PubMed, NCBI/PMC, PEDro, and ISI Web of Knowledge/Science (the latter was also used to identify ISI indexed articles). The contextually searched syntax used was ”Pelotherapy/Peloidotherapy/Mud-therapy/ /Fango-therapy AND Rehabilitation”. The selected articles were analyzed in detail regarding pathologies addressed by mud therapy and country scientific relevance for this therapeutic method. The meta-analysis proceeded was designated to estimate the prevalence of various pathologies in the use of mud therapy. Results. Our search identified, first, 394 articles. Based on the successive filtering stages and, respectively, on the classification criteria of the Physiotherapy Evidence Database (PEDro), we finally identified/retained and analyzed 68 articles. Although, in principle, a rigorous method – and we have followed the PRISMA type paradigm – there still might be some missing works of our related article selection. On the other hand, to augment/ consolidate our documentation base, we have used also 40 papers freely found in the literature, and even – aiming, too, at an as exhaustive knowledge underpinning as possible – derogatively, we have also considered some articles which, probably being very new, couldn't yet have reached the PEDro threshold score we have settled. Conclusions. This paper overviews the current state-of-the-art knowledge in the approach of peloidotherapy in rehabilitation, with a focal point on the therapeutic properties of peloids. Keywords: mud-therapy, pelotherapy, peloidotherapy, fango therapy, rehabilitation, balneotherapy, natural therapeutic factors,