Types Of Plastic Research Articles

Differentially expressed microRNAs in brains of adult females may regulate the maternal block of diapause in Sarcophaga bullata

The maternal regulation of diapause is one type of phenotypic plasticity where the experience of the mother leads to changes in the phenotype of her offspring that impact how well-suited they will be to their future environment. Sarcophaga bullata females with a diapause history produce offspring that cannot enter diapause even if they are reared in a diapause inducing environment. Accumulating evidence suggests that microRNAs regulate diapause and, possibly, maternal regulation of diapause. We found significant differences in the abundances of several microRNAs (miR-125–5p, miR-124–3p, miR-31–5p, and miR-277–3p) in brains dissected from adult female S. bullata that had experienced diapause compared to females with no diapause history. We also found moderate differences in the mRNA expression of the circadian-clock related genes, clock, clockwork orange, and period. MiR-124–3p and miR-31–5p are part of a gene network that includes these circadian clock-related genes. Taken together our results suggest the maternal block of diapause in S. bullata is regulated, at least in part, by a network that includes microRNAs and the circadian clock.

Development of toxicity tests for Polyurethane foams

Polyurethanes (PUs) are a special class of polymeric materials that differ significantly from most other types of plastic in many aspects. They can be utilized in a wide range of products, including paints, coatings, elastomers, insulators, elastic fibers, and foams. PU foams are especially important as part of various convenience products. PU products often end up in landfills when they are no longer useful and can release toxic compounds when damaged by humans or microbes. Therefore, the ecotoxicological assessment of PU foams is essential. In this paper, five PU foam samples were prepared with different NCO indices (NCO-0.8, 0.9, 1.0, 1.1, and 1.2) and together with the Control sample (a previously tested non-toxic foam sample) were applied to develop toxicity tests procedure, while intentionally prepared Toxic foam has been used to verify the accuracy of the developed testing procedure. Two test organisms were successfully applied, Sinapis alba (white mustard) seeds and Escherichia coli (non-pathogenic) bacterial model organisms, and toxicity tests were adapted for the examination of PU-derived substances. Regarding Sinapis alba test, the highest NCO index (NCO-1.2) significantly reduced root length by 9.8 % compared to the Control sample. In the bacterial test, it was observed that the samples containing NCO-1.1 and NCO-1.2 had lower colony numbers (5.0 × 108 and 4.9 × 108 CFU/mL respectively) in comparison to the Control plate (9.6 × 108 CFU/mL). All in all, two toxicity tests were successfully adapted for PU foams, and both are applicable in their ecotoxicological assessment.

Chemo-Enzymatic Depolymerization of Functionalized Low-Molecular-Weight Polyethylene.

Polyethylene (PE) is the most commonly used plastic type in the world, contributing significantly to the plastic waste crisis. Microbial degradation of PE in natural environments is unlikely due to its inert saturated carbon-carbon backbones, which are difficult to break down by enzymes, challenging the development of a biocatalytic recycling method for PE waste. Here, we demonstrated the depolymerization of low-molecular-weight (LMW) PE using an enzyme cascade that included a catalase-peroxidase, an alcohol dehydrogenase, a Baeyer Villiger monooxygenase, and a lipase after the polymer was chemically pretreated with m-chloroperoxybenzoic acid (mCPBA) and ultrasonication. In a preparative experiment with gram-scale pretreated polymers, GC-MS and weight loss determinations confirmed ~27% polymer conversion including the formation of medium-size functionalized molecules such as ω-hydroxy acids and α,ω-carboxylic acids. Additional polymer property analyses using AFM showed that enzymatic depolymerization reduced the particle sizes of this mCPBA- and enzyme-treated LMWPE. This multi-enzyme catalytic concept with distinct chemical steps represents a unique starting point for future development of bio-based recycling methods for polyolefin waste.

Chemo‐Enzymatic Depolymerization of Functionalized Low‐Molecular‐Weight Polyethylene

Polyethylene (PE) is the most commonly used plastic type in the world, contributing significantly to the plastic waste crisis. Microbial degradation of PE in natural environments is unlikely due to its inert saturated carbon‐carbon backbones, which are difficult to break down by enzymes, challenging the development of a biocatalytic recycling method for PE waste. Here, we demonstrated the depolymerization of low‐molecular‐weight (LMW) PE using an enzyme cascade that included a catalase‐peroxidase, an alcohol dehydrogenase, a Baeyer Villiger monooxygenase, and a lipase after the polymer was chemically pretreated with m‐chloroperoxybenzoic acid (mCPBA) and ultrasonication. In a preparative experiment with gram‐scale pretreated polymers, GC‐MS and weight loss determinations confirmed ~27% polymer conversion including the formation of medium‐size functionalized molecules such as ω‐hydroxy acids and α,ω‐carboxylic acids. Additional polymer property analyses using AFM showed that enzymatic depolymerization reduced the particle sizes of this mCPBA‐ and enzyme‐treated LMWPE. This multi‐enzyme catalytic concept with distinct chemical steps represents a unique starting point for future development of bio‐based recycling methods for polyolefin waste.

Comparison of the pyrolysis behavior of PC, ABS and PC/ABS

Three types of plastics—polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS), and PC/ABS blend—were studied in this work. Kinetic analyses were performed using the Flynn-Wall-Ozawa (FWO) and Kissinger–Akahira–Sunose (KAS) methods. The evolved volatiles during the pyrolysis of each material were analyzed, and the pyrolysis behavior was proposed using in-situ tools such as thermogravimetric analyzer-Fourier transform infrared spectroscopic (TG-FTIR) and gas chromatographic separation and mass spectrometry detection (Py-GC/MS). The three samples were also pyrolysed in a fixed bed reactor to elucidate the impact of secondary reaction. For PC, the activation energy increases as the reaction progresses. PC primarily generated CO2 and oxygenated compounds. For ABS, the activation energy experienced a slight decrease once the depolymerization reaction initiates, while a reversed trend can be observed at higher conversion rates. ABS pyrolysis mainly produced nitrogen-containing compounds and mono-aromatics. In the case of PC/ABS blend, a distinctive two-stage decomposition mechanism was observed. The interaction between PC and ABS in the blend promoted the formation of N/O-containing compounds. Additionally, this interaction enhanced the production of lighter phenols at the expense of bisphenol A, while ABS was not affected markedly. Stronger re-condensation and cracking reactions in the fixed bed system, facilitated the formation of poly-aromatics and lighter phenols (p-cresol and 4-ethylphenol) at the expense of bisphenol A during the pyrolysis of PC. In contrast, styrene from ABS decomposition was weakly affected by the secondary reaction. The intensified secondary reactions occurring the sample bed of the fixed bed experiments can also enhance the interaction between volatiles from ABS and PC, forming more heterocyclic N-compounds.

Biotoxicity of silver nanoparticles complicated by the co-existence of micro-/nano-plastics

Silver nanoparticles (AgNP) and polystyrene (PS) plastics have been broadly utilized in various field, e.g., food storage, packaging materials, and medical therapies. However, investigation on the potential biotoxicity induced by the co-exposure to AgNP and PS plastics remains understudied. Thus, we performed this study to examine the toxicological profile of the co-exposure to AgNP and PS in mice. Biochemical and microbial characterizations were performed in mice receiving 90-day oral gavage feeding to examine the hepatotoxicity, neurotoxicity, inflammatory responses, gut microbial alterations. It has been found that the presence of plastic particles aggravates the toxicity of silver nanoparticle materials. Regardless of the plastic type and size, energy and choline metabolisms will be altered by the co-exposures. Moreover, microplastics may induce cell damage by modulating fatty acid peroxidation in unison with stimulating inflammatory responses. Due to the smaller size of nanoplastics, they may pass through blood-brain barrier to induce neuronal damage and increase vascular risks. Changes in the microbial functional abundances are sensitive to the microplastics doses. These results support the necessity of reducing the co-exposure between AgNP and multiscale plastics, and advocate further developments of biodegradable package materials to improve food safety.

Fabrication and characterization of novel biodegradable films based on tomato seed mucilage and gelatin plasticized with polyol mixtures

This research evaluates the potential of tomato seed mucilage (TSM) –gelatin (Ge) in producing edible films. Edible films were made using various ratios of TSM to Ge (1:0, 0.33:0.66, 0.66:0.33, and 0:1). Moreover, the effects of including three types of plasticizers, namely, glycerol (Gly), sorbitol (Sor), and polyethylene glycol (PEG) were investigated. The findings indicated that adding Ge did not affect the thickness of the films (p>0.05). However, it significantly increased the tensile strength (TS) and Young's modulus while reducing the elongation at break (EB) (p˂0.05). A higher TSM ratio significantly increased total color difference (ΔE) and yellowness index while decreasing film lightness and whiteness index (WI) (p˂0.05). The contact angle significantly decreased with the TSM ratio increases and Ge decreases (p˂0.05). Moreover, this led to higher opacity, solubility, moisture content, oxygen permeability, water vapor permeability (WVP), swelling, and moisture absorption (p˂0.05). Adding a plasticizer had no effect on the films' opacity, contact angle, and thickness. The Gly-containing film featured the highest EB, solubility, moisture content, swelling, WVP, oxygen permeability, and moisture absorption. The Sor-containing film had the highest TS. TSM concentration was directly correlated with increased film heterogeneity and surface roughness. X-ray diffraction peaks became sharper by increasing TSM concentration and including PEG, while Gly inclusion produced ordered broad peaks.

Above- and below-ground field study on the impacts of conventional and alternative mesoplastics on Hordeum vulgare growth and soil invertebrate communities

Plastic plays an important role in agriculture, but its use has become a concerning source of pollution. While new (bio)degradable, alternative plastics are being developed and used as mulching films, their ecological impacts, in particular under field conditions, are not well understood. Furthermore, there is a notable lack of knowledge on how plastic pollution affects soil invertebrate communities. Most existing studies primarily focus on microplastics, often neglecting the impacts of mesoplastics. This study therefore compared the separate effects of two conventional (polyethylene and polypropylene) and two alternative (polyethylene containing biodegradable additives and compostable polylactic acid) mesoplastic films on plant performance (biomass, seed yield) and soil mesofaunal assemblages in a field experiment. The mesoplastics were applied at 0.1% (w/w), prior to soil being planted with Hordeum vulgare (spring barley), which was grown to maturity, for 11 weeks. Generally, there were no measurable differences between the conventional and alternative plastic treatments, however, barley exposed to mesoplastics showed reduced biomass, seed yield, and chlorophyll content, along with increased oxidative stress. Soil fauna, particularly Collembola, had lower richness and abundance when exposed to both plastic types, but assemblage structure and composition remained unchanged after 11 weeks. This study is pivotal in highlighting that both conventional and alternative plastics can similarly affect plant health and soil ecosystems. The evidence provided is essential for refining future risk assessments of agricultural plastic pollution and underscores the urgent need for more sustainable practices and materials in agriculture.

The Structural and Functional Responses of Rhizosphere Bacteria to Biodegradable Microplastics in the Presence of Biofertilizers.

Biodegradable microplastics (Bio-MPs) are a hot topic in soil research due to their potential to replace conventional microplastics. Biofertilizers are viewed as an alternative to inorganic fertilizers in agriculture due to their potential to enhance crop yields and food safety. The use of both can have direct and indirect effects on rhizosphere microorganisms. However, the influence of the coexistence of "Bio-MPs and biofertilizers" on rhizosphere microbial characteristics remains unclear. We investigated the effects of coexisting biofertilizers and Bio-MPs on the structure, function, and especially the carbon metabolic properties of crop rhizosphere bacteria, using a pot experiment in which polyethylene microplastics (PE-MPs) were used as a reference. The results showed that the existence of both microplastics (MPs) changed the physicochemical properties of the rhizosphere soil. Exposure to MPs also remarkably changed the composition and diversity of rhizosphere bacteria. The network was more complex in the Bio-MPs group. Additionally, metagenomic analyses showed that PE-MPs mainly affected microbial vitamin metabolism. Bio-MPs primarily changed the pathways related to carbon metabolism, such as causing declined carbon fixation/degradation and inhibition of methanogenesis. After partial least squares path model (PLS-PM) analysis, we observed that both materials influenced the rhizosphere environment through the bacterial communities and functions. Despite the degradability of Bio-MPs, our findings confirmed that the coexistence of biofertilizers and Bio-MPs affected the fertility of the rhizosphere. Regardless of the type of plastic, its use in soil requires an objective and scientifically grounded approach.

Deciphering the role of plasticizers and solvent systems in hydrophobic polymer coating on hydrophilic core

The type of plasticizer and the choice of solvent or co-solvents used for coating of a hydrophilic core can greatly impact the permeability, porosity, and mechanical strength of the polymer film. Although, Ethylcellulose (EC) is an old polymer, it is a polymer of choice for modifying the drug release due to its inherent properties. The ability of polymers like EC alone to form a diffusion-controlling membrane with good mechanical properties is limited. To modulate the drug release as per the desired profile and modify the film properties, ethylcellulose is often used with hydrophilic hypromellose (HPMC) along with plasticizers. The main focus of the current study was the identification of an appropriate solvent system and plasticizer for the ethylcellulose-hypromellose polymer combination. The study evaluated the coating solution properties, the feasibility and efficiency of the process, the physical attributes of the tablet, the surface properties of the polymer film, the in-vitro drug release and behavior, and the impact of curing time on surface properties and drug release, among other factors.The isopropyl alcohol-water mixture (9:1) produced a homogeneous film in comparison to films produced by other solvents. Although both hydrophilic and hydrophobic plasticizers produce homogeneous films, hydrophilic plasticizers have a higher rate of drug diffusion than hydrophobic plasticizers. During the tablet curing and stability study, the drug release from the polymeric film coating with triethyl citrate decreased moderately and with polyethylene glycol decreased significantly. The presence of hydrophobic plasticizers, viz., dibutyl sebacate and acetyl tributyl citrate, in the polymeric film coating does not impact drug release. For the combination of ethylcellulose and hypromellose, it was found that a mixture of isopropyl alcohol and water (9:1) worked better as a solvent for coating solutions, and hydrophobic plasticizers lower the risk associated with coating ethylcellulose and hypromellose together.

Quantifying the content of various types of polypropylene in high density polyethylene blends

To enhance the effectiveness of mechanical plastic recycling, it is best to separate different types of plastic during collection and recycling. This ensures the integrity and quality of recycled materials. For instance, the presence of polypropylene (PP) in recycled polyethylene (PE) can result in inconsistent and undesirable material, impacting the quality and performance of the recycled PE. This underscores the need for an analytical technique to accurately detect the presence of PP in recycled PE materials. In this study, we propose a quantitative analysis using a solution-based crystallization elution fractionation (CEF) technique to assess the polypropylene (PP) content in high-density polyethylene (HDPE) blends. The proposed methodology inherently distinguishes between the semi-crystalline PP matrix, including Homo-PP and Random copolymer PP, as well as the non-crystalline copolymer PP, and then quantifies each segment. A series of commercially available Ziegler–Natta catalyzed polymers were used to obtain the calibration curves per different type of PP materials, i.e., Homo-PP and Random copolymer PP. These calibration curves were then utilized to quantify Homo PP and copolymer PP (either semi-crystalline ethylene-propylene or amorphous ethylene-propylene) in different virgin polymer blends. The proposed methodology provides a comprehensive approach to characterizing the polypropylene content within polyethylene systems, especially in the context of qualifying polyolefin recyclate or polymer blends.

Plastic film from the source of anaerobic digestion: Surface degradation, biofilm and UV response characteristics

This study simulates a major environmental scenario involving “organic fertilizer source” plastics, by exploring the key factors influencing the changes in plastic-films during anaerobic digestion (AD), as well as the responses of the anaerobically digested plastics to ultraviolet (UV) radiation exposure. The results demonstrate that the degradation effect of AD on plastics is reflected by their yellowish and ruptured appearance, slightly worn surfaces, hardening and opacity, and fragmentation. AD significantly increases the content of oxygen-containing functional groups and the degree of unsaturation in plastic films, with thermophilic temperature processes proving more effective than those conducted at mesophilic temperatures. Exposure to UV light has been found to amplify the degradative effects, suggesting the potential cumulative impact of AD and UV. Both AD and UV irradiation reduced the hydrophilicity of plastics. In particular, the hydrophobicity of polylactic acid films was completely disrupted under overlay-exposure. Furthermore, microbial populations on plastic surfaces were mainly bacterial. These bacterial populations were primarily influenced by temperature, and moderately by the plastic types. In contrast, archaea were predominantly affected by both temperature and digested substrate. This study offers a theoretical foundation for strategies aimed at preventing and controlling plastic pollution derived from organic fertilizers.

Characterization of pyroplastics from the North Atlantic

This work describes for the first time the presence of pyroplastics in the Canary Islands (Spain). A total of 300 pyroplastics, identified between 2021 and 2024 in three beaches of the island of Tenerife, present mainly grey and dark colors, a mean weight of 6.8 ± 13.4 g and mean dimensions of 34.2 ± 17.0 mm (X), 24.5 ± 12.2 mm (Y) and 14.4 ± 6.4 (Z). A wide variety of encapsulated and semi-encapsulated materials were also found in the pyroplastics matrix, such as rocks, wood, charcoal and unmelted plastic inclusions. Fourier-transform infrared spectroscopy analysis revealed that polyethylene and polypropylene were the main types of plastic found, 61.3 % and 33.6 %, respectively. However, an important number of pyroplastics composed of more than one polymer were also found, coexisting even mixtures of polyester and polyethylene or polyethylene and styrene-ethylene-butylene-styrene in the same matrix. X-ray fluorescence spectroscopy analysis revealed the presence of a wide range of elements, being remarkable the high concentration of some heavy metals such as Pb and Cr, registering mean concentration values of 205.3 ± 6.3 mg·kg−1 and 51.1 ± 8.9 mg·kg−1, respectively. A good correlation was also found for these two metals in a total of 22 pyroplastics, which could be indicative of the presence of PbCrO4 as additive, widely used in the plastic industry for its bright yellow color, but currently regulated and restricted due to its harmful effects on human and environment health. Also noteworthy is the large variety of remains of marine organisms identified attached to the surface of the pyroplastics, such as algae, bryozoans, arthropods and molluscs, among others, which could indicate that these formations may act as a transport vector for such marine organisms.

Sequential carbonization of pig manure biogas residue into engineered biochar for diethyl phthalate removal toward environmental sustainability

Manure biogas residue has attracted increasing attention in waste recycling but faces substantial challenges because of its low carbon content, high ash content, and high heavy metal content. A novel sequential carbonization approach was proposed for recycling biogas residue; this approach consisted of pre-pyrolysis, activation with Ca(OH)2, and then activation with KOH. Pig manure-derived biogas residue was upcycled into engineered biochar (EB) with a high yield (26 %) and showed excellent performance in removing a typical plasticizer, diethyl phthalate (DEP). The proportion of carbon content greatly increased from 18 % (biogas residue) to 67 % (EB); however, the ash content decreased from 50 % (biogas residue) to 24 % (EB). The concentration of heavy metals decreased, and Zn had the largest decrease from 713 mg kg−1 to 61 mg kg−1 (p < 0.001). The sorption of DEP onto EB was rapid and reached equilibrium within 20 h. The developed specific surface area of EB was 1247 m2/g and provided abundant sorption sites for DEP; additionally, the sorption quantity reached 309 mg/g. The sorption capacity was dominated by surface adsorption. The oxygen-containing functional groups, graphene structure, porous structure, and hydrophobicity of EB contributed to the pore filling, hydrogen bonding, π–π stacking, and partitioning processes. Furthermore, the EB showed excellent practical application potential and great cycling stability. A sequential carbonization strategy was proposed to upcycle manure biogas residue into the EB for DEP removal; moreover, this strategy can aid in the attainment of environmental sustainability, including sustainable waste management and environmental pollution mitigation.

Depuration kinetics and accumulation of microplastics in tissues of mussel Mytilus galloprovincialis

Microplastics (MPs) constitute the predominant plastic type in marine environments. Since they occupy the same size fraction of sediment particles and planktonic organisms they are potentially bioavailable to a broad scope of organisms, such as filter feeders, which are particularly vulnerable to MP ingestion. To understand the potential impact of MPs in filter feeders it is essential to clarify the uptake, accumulation patterns and elimination rates with time of MPs. The aim of this study was to determine the depuration dynamics and accumulation in tissues of mussels Mytilus galloprovincialis exposed during 24 h to different size polystyrene MPs (1 μm and 10 μm), and depurated for a maximum of 7 days (T = 24 h, T = 48 h and T = 7 d). Mussels were chemically digested with KOH 10% and filtered to quantify the number of MP ingested, and they were cryostat sliced for MP localization in tissues. Both MP sizes were quantified in all depuration times, but mussels accumulated significantly higher quantities of 10 μm MP throughout depuration compared to 1 μm MP. A significant decrease was observed after 7 d depuration in mussels exposed to 10 μm. Mussels removed the same amount of 1 and 10 μm MP after 7 days depuration. However, the depuration dynamics differed for each size-MPs and showed to be size-dependent. Most of both size MPs were eliminated in the first 24 h, but 1 μm MP showed to pass faster through the digestive tract than 10 μm MP. MPs of 1 μm and 10 μm were localized mainly in the lumen and a few in the epithelium of the digestive tract (stomach, intestine and digestive gland) during the depuration and in the gills after the exposure; as confirmed by Raman spectroscopy. The usage of chemical digestion and histological analysis as complementary techniques show to be suitable to infer the depuration dynamics of MPs in mussels.

Plastics in the Indian economy: a comprehensive material flow analysis

AbstractPlastic is valued for its flexibility to be utilized in different applications, yet it poses a significant threat to our environment because of mismanaged plastic waste. India’s compound annual growth of plastic consumption has been around 7% for a decade. Despite this significant growth, there has not been a comprehensive study of Indian plastic flows since 2000. This work presents a 20-year update, detailing plastic production, consumption by all plastic types and sectors, and the overall material flow for 2018–19 to fill the gap in the data on post-consumer plastic flows. The analysis reveals a total plastic production of 19.3 Mt, 22% of which is Polyethylene as the most wildly used plastic. The total mass of plastic in products distributed in various applications is 23.9 Mt. Key sectors for plastic consumption are Packaging (30%), Textiles (17%), and Buildings and Construction (16%). Plastic waste generation is 15.5 Mt, primarily from packaging and textiles. Only 13% of this plastic gets recycled, 46% is mismanaged, and the rest incinerated or dumped. The study’s unique nationwide, mass-balanced, transparent approach offers a rigorous reference point for decision-makers. Yet, the lack of reliable data is the main barrier to design, implement, and monitor of policy interventions.

Biodegradation of poly(butylene adipate terephthalate) and poly(vinyl alcohol) within aquatic pathway

Understanding the environmental fate of biodegradable plastics in aquatic systems is crucial, given the alarming amount of plastic waste and microplastic particles transported through aquatic pathways. In particular, there is a need to analyze the biodegradation of commercialized biodegradable plastics upon release from wastewater treatment plants into natural aquatic systems. This study investigates the biodegradation behaviors of poly(butylene adipate terephthalate) (PBAT) and poly(vinyl alcohol) (PVA) in wastewater, freshwater, and seawater. Biodegradation of PBAT and PVA assessed through biochemical oxygen demand (BOD) experiments and microcosm tests revealed that the type of aquatic system governs the biodegradation behaviors of each plastic, with the highest biodegradation rate achieved in wastewater for both PBAT and PVA (25.6 and 32.2 % in 30 d, respectively). Plastic release pathway from wastewater into other aquatic systems simulated by sequential incubation in different microcosms suggested that PBAT exposed to wastewater and freshwater before reaching seawater was more prone to degradation than when directly exposed to seawater. On the other hand, PVA displayed comparable biodegradation rate regardless of whether it was directly exposed to seawater or had passed through other environments beforehand. Metagenome amplicon sequencing of 16S rRNA genes revealed distinct community shifts dependent on the type of plastics in changing environments along the simulated aquatic pathway. Several bacterial species putatively implicated in the biodegradation of PBAT and PVA are discussed. Our findings underscore the significant influence of pollution routes on the biodegradation of PBAT and PVA, highlighting the potential for wastewater treatment to facilitate rapid degradation compared to direct exposure to pristine aquatic environments.

Plastic Debris in the Aquatic Environment: An Emerging Substratum for Antimicrobial Resistant (AMR) Biofilms.

Plastic pollution has quadrupled over the past years and has become a global concern due to its direct impact on life forms. The present study analysed whether the plastic debris in aquatic environments could act as the substratum for the antimicrobial-resistant (AMR) bacteria to form biofilm for survival. We have collected various plastic debris (n = 32) from six sites of the Periyar River, the drinking water source for the entire city and one of the most polluted rivers in Kerala (India). The chemical composition of plastics was screened via FTIR analysis and found that they comprised two types, viz., polyethylene and polypropylene. Bacteria isolated from the samples were screened for the AMR characteristics towards eight different classes of antibiotics. All isolates showed 100% resistance towards colistin and obtained the MAR index value of 0.1-0.4 range. Six representative bacterial isolates with high multiple antibiotic resistance (MAR) index were selected and identified by 16sRNA sequencing as Lysinibacillus mangiferihumi, Bacillus pumilus, Bacillus safensis, Bacillus cereus, Bacillus altitudins and Bacillus pumilus. In vitro biofilm formation was experimented on the purchased plastic samples in artificial media and river water using two selected strains, Bacillus pumilus and Bacillus cereus. Significant variations were observed in biofilm growth in different media (P < 0.05) regardless of plastic types (P > 0.05). The extracellular polymeric substances (EPS) and the characteristic holes on the surface morphology were visualized in SEM analysis, thus indicating the conditioning of the plastics by the isolates for biofilm formation.

Myosin XVA isoforms participate in the mechanotransduction-dependent remodeling of the actin cytoskeleton in auditory stereocilia.

Auditory hair cells form precise and sensitive staircase-like actin protrusions known as stereocilia. These specialized microvilli detect deflections induced by sound through the activation of mechano-electrical transduction (MET) channels located at their tips. At rest, a small MET channel current results in a constant calcium influx, which regulates the morphology of the actin cytoskeleton in the shorter 'transducing' stereocilia. However, the molecular mechanisms involved in this novel type of activity-driven plasticity in the stereocilium cytoskeleton are currently unknown. Here, we tested the contribution of myosin XVA (MYO15A) isoforms. We used electron microscopy to evaluate morphological changes in the cytoskeleton of auditory hair cell stereocilia after the pharmacological blockage of resting MET currents in cochlear explants from mice that lacked one or all isoforms of MYO15A. Hair cells lacking functional MYO15A isoforms did not exhibit MET-dependent remodeling in their stereocilia cytoskeleton. In contrast, hair cells that only lack the long isoform of MYO15A exhibited increased MET-dependent stereocilia remodeling, including remodeling in stereocilia from the tallest 'non-transducing' row of the bundle. We conclude that MYO15A isoforms not only enable but also fine-tune the MET-dependent remodeling of the actin cytoskeleton in transducing stereocilia and contribute to the stability of the tallest row.

Impact of Calcium Chloride Addition on the Microstructural and Physicochemical Properties of Pea Protein Isolate-Based Films Plasticized with Glycerol and Sorbitol

Ca2+ can boost protein-protein interactions and, if present at an appropriate level, can potentially improve some physicochemical properties of protein-based gels and films. This study aimed to determine the effects of CaCl2 (0%–0.05% w/w) on the microstructural, optical, water affinity, and mechanical characteristics of glycerol (Gly)- and sorbitol (Sor)-plasticized pea protein isolate (PPI)-based films. CaCl2 caused darkening and a color shift of the films from yellow to yellow-green. Additionally, decreased light transmission, particularly in the UV range, acidification, and reduced moisture content were observed. CaCl2 decreased the water vapor permeability of the Gly plasticized film by an average of 20% with no effect on the Sor-plasticized film. All films were completely soluble in water. CaCl2 negatively impacted the mechanical integrity of the films, reducing the tensile strength of the Gly- and Sor-plasticized films by ~16% and 14%–37%, respectively. Further increases in CaCl2 content (0.1% and 0.2% w/w) led to concentration-dependent microvoids resulting from protein over-crosslinking and/or coagulation. In summary, the incorporation of CaCl2 into PPI-based films did not provide significant benefits and actually worsened key properties, such as transparency and mechanical strength. The type of plasticizer influenced how CaCl2 affected some properties of the PPI-based film.