Microplastic Materials for Inhalation Studies: Preparation by Solvent Precipitation and Comprehensive Characterization.

Assessing the inhalation hazard of microplastics is important but necessitates sufficient quantity of microplastics that are representative and respirable (<4 µm). Common plastics are not typically manufactured in such small sizes. Here, solvent precipitation is used to produce respirable test materials from thermoplastics polyurethane (TPU), polyamide (PA-6), polyethylene terephthalate (PET), and low-density polyethylene (LDPE).

Altering glycopeptide antibiotic biosynthesis through mutasynthesis allows incorporation of fluorinated phenylglycine residues.

Glycopeptide antibiotics (GPAs) are peptide natural products used as last resort treatments for antibiotic resistant bacterial infections. They are produced by the sequential activities of a linear nonribosomal peptide synthetase (NRPS), which assembles the heptapeptide core of GPAs, and cytochrome P450 (Oxy) enzymes, which perform a cascade of cyclisation reactions. The GPAs contain proteinogenic and nonproteinogenic amino acids, including phenylglycine residues such as 4-hydroxyphenylglycine (Hpg).

Role of Carbon, Nitrogen, Phosphate and Sulfur Metabolism in Secondary Metabolism Precursor Supply in spp.

The natural soil environment of is characterized by variations in the availability of nitrogen, carbon, phosphate and sulfur, leading to complex primary and secondary metabolisms. Their remarkable ability to adapt to fluctuating nutrient conditions is possible through the utilization of a large amount of substrates by diverse intracellular and extracellular enzymes. Thus, fulfill an important ecological role in soil environments, metabolizing the remains of other organisms.

Next Generation Risk Assessment approaches for advanced nanomaterials: Current status and future perspectives.

This manuscript discusses the challenges of applying New Approach Methodologies (NAMs) for safe by design and regulatory risk assessment of advanced nanomaterials (AdNMs). The authors propose a framework for Next Generation Risk Assessment of AdNMs involving NAMs that is aligned to the conventional risk assessment paradigm. This framework is exposure-driven, endpoint-specific, makes best use of pre-existing information, and can be implemented in tiers of increasing specificity and complexity of the adopted NAMs.

Bioinformatics and machine learning to support nanomaterial grouping.

Nanomaterials (NMs) offer plenty of novel functionalities. Moreover, their physicochemical properties can be fine-tuned to meet the needs of specific applications, leading to virtually unlimited numbers of NM variants. Hence, efficient hazard and risk assessment strategies building on New Approach Methodologies (NAMs) become indispensable.

Desorption of Polycyclic Aromatic Hydrocarbons from Microplastics in Human Gastrointestinal Fluid Simulants-Implications for Exposure Assessment.

Microplastics have been detected in various food types, suggesting inevitable human exposure. A major fraction may originate from aerial deposition and could be contaminated by ubiquitous pollutants such as polycyclic aromatic hydrocarbons (PAHs). While data on the sorption of pollutants to microplastics are abundant, the subsequent desorption in the gastrointestinal tract (GIT) is less understood.

Toxicological inhalation studies in rats to substantiate grouping of zinc oxide nanoforms.

Background: Significant variations exist in the forms of ZnO, making it impossible to test all forms in in vivo inhalation studies. Hence, grouping and read-across is a common approach under REACH to evaluate the toxicological profile of familiar substances. The objective of this paper is to investigate the potential role of dissolution, size, or coating in grouping ZnO (nano)forms for the purpose of hazard assessment.

Everything falls apart: How solids degrade and release nanomaterials, composite fragments, and microplastics.

To ensure the safe use of materials, one must assess the identity and quantity of exposure. Solid materials, such as plastics, metals, coatings and cements, degrade to some extent during their life cycle, and releases can occur during manufacturing, use and end-of-life. Releases (e.

A Screening Approach to the Safe-and-Sustainable-by-Design Development of Advanced Insulation Materials.

Herein, a Safe-and-Sustainable-by-Design (SSbD) screening strategy on four different inorganic aerogel mats and two conventional mineral wools for ranking purposes is demonstrated. Given that they do not consist of particles, the release is first simulated, addressing three occupational exposure scenarios, realistic for their intended use as building insulators. No exposure to consumers nor to the environment is foreseen in the use phase, however, aerosols may be released during mat installation, posing an inhalation risk for workers.

Tracking Dynamic Chemical Reactivity Networks with High-Resolution Mass Spectrometry: A Case of Microplastic-Derived Dissolved Organic Carbon.

Chemical degradation testing often involves monitoring the loss of a chemical or the evolution of a single diagnostic product through time. Here, we demonstrate a novel approach to tracing complex degradation networks using mass-spectrometry-based methods and open cheminformatics tools. Ester- and ether-based thermoplastic polyurethane (TPU_Ester and TPU_Ether) microplastics (350 μm) and microplastics-derived dissolved organic carbon (MP-DOC) were photoweathered in a simulated marine environment and subsequently analyzed by liquid chromatography coupled to high-resolution mass spectrometry.

The power of centrifugation: How to extract microplastics from soil with high recovery and matrix removal efficiency.

Understanding the occurrence and transformation of microplastics when released into the environment is essential for risk assessment. The use of biodegradable polymers in agriculture can help to reduce microplastic accumulation in soil, since released fragments of such materials are not persistent and are further transformed into CO and biomass (Wohlleben et al., 2023).

Critical aspects in dissolution testing of nanomaterials in the oro-gastrointestinal tract: the relevance of juice composition for hazard identification and grouping.

The dissolution of a nanomaterial (NM) in an simulant of the oro-gastrointestinal (OGI) tract is an important predictor of its biodurability . The cascade addition of simulated digestive juices (saliva, stomach and intestine), including inorganic/organic biomacromolecules and digestive enzymes (complete composition, referred to as "Type 1 formulation"), strives for realistic representation of chemical composition of the OGI tract. However, the data robustness requires consideration of analytical feasibility, such as the use of simplified media.

An innovative microplastic extraction technique: The switchable calcium chloride density separation column tested for biodegradable polymers, polyethylene, and polyamide.

Extracting microplastics from complex matrices poses challenges due to the potential impact of harsh chemical treatments on microplastic properties. For fate and hazard assessment reliable techniques are needed to not only quantify the particle number but also to assess the physicochemical properties of environmental microplastics with minimum changes induced by extraction. Here we present the method development for an innovative and non-destructive extraction protocol based on a switchable calcium chloride density separation column.

A novel synthetic inhibitor of polyamine utilization in Streptomyces coelicolor.

In this work, we present the first inhibitor of GlnA2Sc, a gamma-glutamylpolyamine synthetase, which allows Streptomyces coelicolor to detoxify high concentrations of polyamines and to utilize them as a carbon or nitrogen source. GlnA2 belongs to the class of glutamine synthetase-like (GS-like) enzymes that catalyze the glutamylation of different nitrogen-containing compounds. Whereas a number of inhibitors for GS are known, none of them are known to inhibit GlnA2.

Three-tiered approach for standard information requirements for polymers requiring registration under REACH.

Polymers are a very large class of chemicals comprising often complex molecules with multiple functions used in everyday products. The EU Commission is seeking to develop environmental and human health standard information requirements (SIRs) for man-made polymers requiring registration (PRR) under a revised Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) Regulation. Conventional risk assessment approaches currently used for small molecules may not apply to most polymers.

Reply to comment on "which fraction of stone wool fibre surface remains uncoated by binder? A detailed analysis by time-of-flight secondary ion mass spectrometry and X-ray photoelectron spectroscopy" by Hirth , 2021, , 11, 39545, DOI: 10.1039/d1ra06251d".

This is a reply to the Comment of Okhrimenko in the same issue of . We discuss the arguments brought forward by said authors, oppose their objections and show the unchanged validity of our results.

Metabolic engineering of the shikimate pathway in Amycolatopsis strains for optimized glycopeptide antibiotic production.

Glycopeptide antibiotics (GPA) consist of a glycosylated heptapeptide backbone enriched in aromatic residues originating from the shikimate pathway. Since the enzymatic reactions within the shikimate pathway are highly feedback-regulated, this raises the question as to how GPA producers control the delivery of precursors for GPA assembly. We chose Amycolatopsis balhimycina, the producer of balhimycin, as a model strain for analyzing the key enzymes of the shikimate pathway.

NanoDefiner Framework and e-Tool Revisited According to the European Commission's Nanomaterial Definition 2022/C 229/01.

The new recommended definition of a nanomaterial, 2022/C 229/01, adopted by the European Commission in 2022, will have a considerable impact on European Union legislation addressing chemicals, and therefore tools to implement this new definition are urgently needed. The updated NanoDefiner framework and its e-tool implementation presented here are such instruments, which help stakeholders to find out in a straightforward way whether a material is a nanomaterial or not. They are two major outcomes of the NanoDefine project, which is explicitly referred to in the new definition.

Optimization of FK-506 production in Streptomyces tsukubaensis by modulation of Crp-mediated regulation.

FK-506 is a potent immunosuppressive macrocyclic polyketide with growing pharmaceutical interest, produced by Streptomyces tsukubaensis. However, due to low levels synthesized by the wild-type strain, biotechnological production of FK-506 is rather limited. Optimization strategies to enhance the productivity of S.

Photochemical weathering of polyurethane microplastics produced complex and dynamic mixtures of dissolved organic chemicals.

Sunlight exposure can naturally mitigate microplastics pollution in the surface ocean, however it results in emissions of dissolved organic carbon (DOC) whose characteristics and fate remain largely unknown. In this work, we investigated the effects of solar radiation on polyether (TPU_Ether) and polyester (TPU_Ester) thermoplastic polyurethane, and on a thermoset polyurethane (PU_Hardened). The microplastics were irradiated with simulated solar light with a UV dose of 350 MJ m, which corresponds to roughly 15 months outdoor exposure at 31° N latitude.

Optimization of the precursor supply for an enhanced FK506 production in .

Tacrolimus (FK506) is a macrolide widely used as immunosuppressant to prevent transplant rejection. Synthetic production of FK506 is not efficient and costly, whereas the biosynthesis of FK506 is complex and the level produced by the wild type strain, , is very low. We therefore engineered FK506 biosynthesis and the supply of the precursor L-lysine to generate strains with improved FK506 yield.

Grouping of orally ingested silica nanomaterials via use of an integrated approach to testing and assessment to streamline risk assessment.

Background: Nanomaterials can exist in different nanoforms (NFs). Their grouping may be supported by the formulation of hypotheses which can be interrogated via integrated approaches to testing and assessment (IATA). IATAs are decision trees that guide the user through tiered testing strategies (TTS) to collect the required evidence needed to accept or reject a grouping hypothesis.