The interweaving roles of mineral and microbiome in shaping the antibacterial activity of archaeological medicinal clays

Ethnopharmacological relevance: Medicinal Earths (MEs), natural aluminosilicate-based substances (largely kaolinite and montmorillonite), have been part of the European pharmacopoeia for well over two millennia; they were used generically as antidotes to ‘poison’. Aim of the study: To test the antibacterial activity of three Lemnian and three Silesian Earths, medicinal earths in the collection of the Pharmacy Museum of the University of Basel, dating to 16th-18th century and following the methodology outlined in the graphical abstract. To compare them with natural clays of the same composition (reference clays) and synthetic clays (natural clays spiked with elements such as B, Al, Ti and Fe); to assess the parameters which drive antibacterial activity, when present, in each group of samples. Materials and methods: a total of 31 samples are investigated chemically (ICP-MS), mineralogically (both bulk (XRD) and at the nano-sized level (TEM-EDAX)); their organic load (bacterial and fungal) is DNA-sequenced; their bioactivity (MIC 60) is tested against Gram-positive, S. aureus and Gram-negative, P. aeruginosa. Results: Reference smectites and kaolinites show no antibacterial activity against the above pathogens. However, the same clays when spiked with B or Al (but not with Ti or Fe) do show antibacterial activity. Of the six MEs, only two are antibacterial against both pathogens. Following DNA sequencing of the bioactive MEs, we show the presence within of a fungal component, Talaromyces sp, a fungus of the family of Trichocomaceae (order Eurotiales), historically associated with Penicillium. Talaromyces is a known producer of the exometabolite bioxanthracene B, and in an earlier publication we have already identified a closely related member of the bioxanthracene group, in association with one of the LE samples examined here. By linking fungus to its exometabolite we suggest that this fungal load may be the key parameter driving antibacterial activity of the MEs. Conclusions: Antibacterial activity in kaolinite and smectite clays can arise either from spiking natural clays with elements like B and Al, or from an organic (fungal) load found only within some archaeological earths. It cannot be assumed, a priori, that this organic load was acquired randomly and as a result of long-term storage in museum collections. This is because, at least in the case of medicinal Lemnian Earth, there is historical evidence to suggest that the addition of a fungal component may have been deliberate

Relationship between hydrothermal fluids and microseismic activity on the south-east coast of Milos Island

Η Μήλος ανήκει creo Ελληνικό ηφαιστειακό τόξο και είναι με'λος ενός αριθμοί; θερμών κηλίδων. Χαρακτηρίζεται από την ύπαρξη γεωθερμικού πεδίου υψηλής ενθαλπίας και από μία μη συνεχή μικροσεισμική δραστηριότητα, που εκφράζεται μέσω τεκτονικών σεισμών και σμηνοσειρών. Αυτή, κατά την περίοδο μελέτης, ήταν πολύ μικρή και περιορισμένη στο ΝΑ τμήμα της νήσου. Από τις χημικές αναλύσεις δεν διαπιστώθηκαν μεταβολές στη σύσταση των υδροθερμικών ρευστών, παρά μόνο μικρές αυξομειώσεις στο Κ, το Ca και το Li και ακόμα μικρότερες για το Mg και το Fe. Αυτό υποδεικνύει την πιθανή ύπαρξη μιας σχέσης μεταξύ μικροσεισμικής δραστηριότητας και μεταβολών στις συγκεντρώσεις κάποιων στοιχείων, η οποία όμως απαιτεί περαιτέρω διερεύνηση για ένα μεγαλύτερο χρονικό διάστημα.Milos island belongs to the Greek volcanic arc and is part of a small number of hot spots in the South Aegean Sea. It is an area that stands out for the diversity in volcanic formations and chemical composition of rocks. The island is characterized by the presence of a high enthalpy geothermal field and a non continuous microseismic activity, expressed both by tectonic earthquakes and swarm activity. During the period of our study (May-December 1999), this activity, which was recorded by a small, portable, seismological network has been very small and limited in the SE part of the island. From the chemical analyses performed, no significant alterations in the composition of the hydrothermal fluids was detected, except from slight changes in the content of K, Ca and Li and even smaller changes in Mg and Fe. This fact certainly implies a possible relation between microseismic activity and alterations in the content of various chemical elements, but it still needs further verification, which means that our research should be prolonged for a time period of at least two year

Mineralogical sources of groundwater fluoride in Archaen bedrock/regolith aquifers: Mass balances from southern India and north-central Sri Lanka

STUDY REGION: The Maheshwaram and Waipally catchments of Andhra Pradesh, India, and the Plonnaruwa catchment of north-central Sri Lanka. STUDY FOCUS: The distribution of F across eight crystalline phases and between the bedrock and the regolith at eleven sites in three catchments is documented. Mineral contributions to F release during weathering and regolith development are quantified. NEW HYDROLOGICAL INSIGHTS FOR THE REGION: An estimate of weathering duration for the in situ regolith in Andhra Pradesh, 250-380 Ka, is close to a previous estimate for southern India. Partial or total destruction of the primary F-bearing bedrock minerals and consistent depletion of F in the remnant minerals result in a much reduced total F content in the regolith. Leaching experiments and field relationships, however, indicate a greater potential for F mobilisation to groundwater from the regolith than the bedrock. Schemes for managed aquifer recharge should beware the risk of mobilising additional F to groundwater

A safe-by-design tool for functionalised nanomaterials through the Enalos Nanoinformatics Cloud platform

Multi-walled carbon nanotubes are currently used in numerous industrial applications and products, therefore fast and accurate evaluation of their biological and toxicological effects is of utmost importance. Computational methods and techniques, previously applied in the area of cheminformatics for the prediction of adverse effects of chemicals, can also be applied in the case of nanomaterials (NMs), in an effort to reduce expensive and time consuming experimental procedures. In this context, a validated and predictive nanoinformatics model has been developed for the accurate prediction of the biological and toxicological profile of decorated multi-walled carbon nanotubes. The nanoinformatics workflow was fully validated according to the OECD principles before it was released online via the Enalos Cloud platform. The web-service is a ready-to-use, user-friendly application whose purpose is to facilitate decision making, as part of a safe-by-design framework for novel carbon nanotubes

Impact of particle size, oxidation state and capping agent of different cerium dioxide nanoparticles on the phosphate-induced transformations at different pH and concentration

The potential hazard posed by nanomaterials can be significantly influenced by transformations which these materials undergo during their lifecycle, from manufacturing through to disposal. The transformations may depend on the nanomaterials’ own physicochemical properties as well as the environment they are exposed to. This study focuses on the mechanisms of transformation of cerium oxide nanoparticles (CeO$_{2}$ NPs) in laboratory experiments which simulate potential scenarios in which the NPs are exposed to phosphate-bearing media. We have experimented with the transformation of four different kinds of CeO$_{2}$ NPs, in order to investigate the effects of nanoparticle size, capping agent (three were uncapped and one was PVP capped) and oxidation state (two consisted mostly of Ce$^{4+}$ and two were a mix of Ce$^{3+}$/Ce$^{4+}$). They were exposed to a reaction solution containing KH$_{2}$PO$_{4}$, citric acid and ascorbic acid at pH values of 2.3, 5.5 and 12.3, and concentrations of 1mM and 5mM. The transformations were followed by UV-vis, zeta potential and XRD measurements, which were taken after 7 and 21 days, and by transmission electron microscopy after 21 days. X-ray photoelectron spectroscopy was measured at 5mM concentration after 21 days for some samples. Results show that for pH 5 and 5mM phosphate concentration, CePO$_{4}$ NPs were formed. Nanoparticles that were mostly Ce$^{4+}$ did not dissolve at 1mM reagent concentration, and did not produce CePO$_{4}$ NPs. When PVP was present as a capping agent it proved to be an extra reducing agent, and CePO$_{4}$ was found under all conditions used. This is the first paper where the transformation of CeO$_{2}$ NPs in the presence of phosphate has been studied for particles with different size, shapes and capping agents, in a range of different conditions and using many different characterisation methods

Greco-Roman mineral (litho)therapeutics and their relationship to their microbiome : the case of the red pigment miltos

This paper introduces a holistic approach to the study of Greco-Roman (G-R) lithotherapeutics. These are the minerals or mineral combinations that appear in the medical and scientific literature of the G-R world. It argues that they can best be described not simply in terms of their bulk chemistry/mineralogy but also their ecological microbiology and nanofraction component. It suggests that each individual attribute may have underpinned the bioactivity of the lithotherapeutic as an antibacterial, antifungal or other. We focus on miltos, the highly prized, naturally fine, red iron oxide-based mineral used as a pigment, in boat maintenance, agriculture and medicine. Five samples (four geological (from Kea, N. Cyclades) and one archaeological (from Lemnos, NE Aegean)) of miltos were analyzed with physical and biological science techniques. We show that: a. Kean miltos and Lemnian earth/miltos must have been chemically and mineralogically different; b. Lemnian miltos must have been more effective as an antibacterial against specific pathogens (Gram + and Gram − bacteria) than its Kean counterpart; c. two samples of Kean miltos, although similar, chemically, mineralogically and eco-microbiologically (phylum/class level), nevertheless, displayed different antibacterial action. We suggest that this may constituteproof of microbial ecology playing an important role in effecting bioactivity and, interestingly, at the more specific genus/species level. From the perspective of the historian of G-R science, we suggest that it may have been on account of its bioactivity, rather than simply its 'red-staining' effect, that miltos gained prominent entry into the scientific and medical literature of the G-R world

Climate Change and Biosphere Response: Unlocking the Collections Vault

Natural history collections (NHCs) are an important source of the long-term data needed to understand how biota respond to ongoing anthropogenic climate change. These include taxon occurrence data for ecological modeling, as well as information that can be used to reconstruct mechanisms through which biota respond to changing climates. The full potential of NHCs for climate change research cannot be fully realized until high-quality data sets are conveniently accessible for research, but this requires that higher priority be placed on digitizing the holdings most useful for climate change research (e.g., whole-biota studies, time series, records of intensively sampled common taxa). Natural history collections must not neglect the proliferation of new information from efforts to understand how present-day ecosystems are responding to environmental change. These new directions require a strategic realignment for many NHC holders to complement their existing focus on taxonomy and systematics. To set these new priorities, we need strong partnerships between NHC holders and global change biologists

A review on nanomaterial-based SERS substrates for sustainable agriculture

The agricultural sector plays a pivotal role in driving the economy of many developing countries. Any dent in this economical structure may have a severe impact on a country's population. With rising climate change and increasing pollution, the agricultural sector is experiencing significant damage. Over time this cumulative damage will affect the integrity of food crops and create food security issues around the world. Therefore, an early warning system is needed to detect possible stress on food crops. Here we present a review of the recent developments in nanomaterial-based Surface Enhanced Raman Spectroscopy (SERS) substrates which could be utilized to monitor agricultural crop responses to natural and anthropogenic stress. Initially, our review delves into diverse and cost-effective strategies for fabricating SERS substrates, emphasizing their intelligent utilization across various agricultural scenarios. In the second phase of our review, we spotlight the specific application of SERS in addressing critical food security issues. By detecting nutrients, hormones, and effector molecules in plants, SERS provides valuable insights into plant health. Furthermore, our exploration extends to the detection of contaminants, chemicals, and foodborne pathogens within plants, showcasing the versatility of SERS in ensuring food safety. The cumulative knowledge derived from these discussions illustrates the transformative potential of SERS in bolstering the agricultural economy. By enhancing precision in nutrient management, monitoring plant health, and enabling rapid detection of harmful substances, SERS emerges as a pivotal tool in promoting sustainable and secure agricultural practices. Its integration into agricultural processes not only augments productivity but also establishes a robust defence against potential threats to crop yield and food quality. As SERS continues to evolve, its role in shaping the future of agriculture becomes increasingly pronounced, promising a paradigm shift in how we approach and address challenges in food production and safety

Thermal transformations of manufactured nanomaterials as a proposed proxy for ageing

Ageing is an important part of a manufactured nanomaterial\u27s life cycle and can be considered as a transformation over time. It is particularly relevant to nanomaterials (NMs) because they are more reactive than their bulk counterparts and therefore are likely to undergo more significant or faster transformations with time. The conditions upon exposure of a NM to the environment, e.g. temperature, humidity and redox, will all individually affect ageing, as well as time. In experimental simulations, time has to be substituted by a proxy that makes timescales more realistic. Thermal ageing accelerates the normal ageing processes of NMs and thus elevated temperatures can be used to simulate prolonged ageing, allowing access to information on the long-term effects of NM ageing within a shorter time. Similar approaches are utilised in experimental simulation of protein fibrillation, for example, where processes that naturally occur over decades are accelerated to days or hours. In this work, time and temperature dependent studies were carried out on a fully characterised library of laboratory synthesised comparable polyvinylpyrrolidone (PVP) capped NMs (with core compositions of ceria, copper oxide and zinc oxide) and a commercially available uncoated cerium dioxide NM, to assess their transformations. Specifically, physical and chemical changes were studied on NMs exposed to various temperatures (25, 45, 65 and 80 °C) for a period of 4 weeks. The size, zeta potential, agglomeration/aggregation and valence state of the NMs were studied through dynamic light scattering (DLS), zeta potential, ultra-violet visible light spectroscopy (UV-VIS), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS), as a function of time. Results generally show a decrease in NM stability with increasing temperature and time. Changes in the NM size and core oxidation state were noted with increasing temperature/time. These changes varied depending on the NM core composition. Additionally the PVP capping, despite stabilising the NM dispersion, still allowed the NM core to be influenced by external factors, thus indicating likely ageing-related reduction in efficiency, though to a lesser extent than the uncapped particles. Overall the experiments recorded a complex picture of transformations as a function of time/temperature highlighting the complexity of NMs\u27 ageing

Impact of particle size, oxidation state and capping agent of different cerium dioxide nanoparticles on the phosphate-induced transformations at different pH and concentration

The potential hazard posed by nanomaterials can be significantly influenced by transformations which these materials undergo during their lifecycle, from manufacturing through to disposal. The transformations may depend on the nanomaterials’ own physicochemical properties as well as the environment they are exposed to. This study focuses on the mechanisms of transformation of cerium oxide nanoparticles (CeO2 NPs) in laboratory experiments which simulate potential scenarios in which the NPs are exposed to phosphate-bearing media. We have experimented with the transformation of four different kinds of CeO2 NPs, in order to investigate the effects of nanoparticle size, capping agent (three were uncapped and one was PVP capped) and oxidation state (two consisted mostly of Ce4+ and two were a mix of Ce3+/Ce4+). They were exposed to a reaction solution containing KH2PO4, citric acid and ascorbic acid at pH values of 2.3, 5.5 and 12.3, and concentrations of 1mM and 5mM. The transformations were followed by UV-vis, zeta potential and XRD measurements, which were taken after 7 and 21 days, and by transmission electron microscopy after 21 days. X-ray photoelectron spectroscopy was measured at 5mM concentration after 21 days for some samples. Results show that for pH 5 and 5mM phosphate concentration, CePO4 NPs were formed. Nanoparticles that were mostly Ce4+ did not dissolve at 1mM reagent concentration, and did not produce CePO4 NPs. When PVP was present as a capping agent it proved to be an extra reducing agent, and CePO4 was found under all conditions used. This is the first paper where the transformation of CeO2 NPs in the presence of phosphate has been studied for particles with different size, shapes and capping agents, in a range of different conditions and using many different characterisation methods