To investigate the formation of polystyrene nanoplastic-plant protein corona and its potential impact on plants, three differently modified polystyrene nanoplastics with an average particle size of 200 nm were taken to interact with the leaf proteins of Impatiens hawkeri for 2 h, 4 h, 8 h, 16 h, 24 h, and 36 h, respectively. The morphological changes were observed by scanning electron microscopy (SEM), the surface roughness was determined by atomic force microscopy (AFM), the hydrated particle size and zeta potential were determined by nanoparticle size and zeta potential analyzer, and the protein composition of the protein corona was identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The proteins were classified in terms of biological processes, cellular components, and molecular functions to study the adsorption selection of nanoplastics to proteins, investigate the formation and characteristics of polystyrene nanoplastic-plant protein corona and predict the potential impact of protein corona on plants. The results showed that the morphological changes of the nanoplastics became clearer as the reaction time extends, as evidenced by the increase in size and roughness and the enhancement of stability, thus demonstrating the formation of protein corona. In addition, the transformation rate from soft to hard protein corona was basically the same for the three polystyrene nanoplastics in the formation of protein corona with leaf proteins under the same protein concentration conditions. Moreover, in the reaction with leaf proteins, the selective adsorption of the three nanoplastics to proteins with different isoelectric points and molecular weights differed, and the particle size and stability of the final formed protein corona also differed. Since a large portion of the protein fraction in protein corona is involved in photosynthesis, it is hypothesized that the formation of the protein corona may affect photosynthesis in I. hawkeri.
Polystyrenes/chemistry* ; Protein Corona/chemistry* ; Microplastics ; Plant Proteins ; Chromatography, Liquid ; Tandem Mass Spectrometry ; Nanoparticles/chemistry*

OBJECTIVE: This study was designed to provide the evidences on the toxicokinetics of microplastics (MPs) and nanoplastics (NPs) in the bodies of mammals. METHODS: 100 nm, 3 μm, and 10 μm fluorescent polystyrene (PS) beads were administered to mice once by gavage at a dose of 200 mg/kg body weight. The levels and change of fluorescence intensity in samples of blood, subcutaneous fat, perirenal fat, peritesticular fat, cerebrum, cerebellum, testis, and epididymis were measured at 0.5, 1, 2, and 4 h after administration using an IVIS Spectrum small-animal imaging system. Histological examination, confocal laser scanning, and transmission electron microscope were performed to corroborate the findings. RESULTS: After confirming fluorescent dye leaching and impact of pH value, increased levels of fluorescence intensity in blood, all adipose tissues examined, cerebrum, cerebellum, and testis were measured in the 100 nm group, but not in the 3 and 10 μm groups except in the cerebellum and testis at 4 h for the 3 μm PS beads. The presence of PS beads was further corroborated. CONCLUSION After a single oral exposure, NPs are absorbed rapidly in the blood, accumulate in adipose tissues, and penetrate the blood-brain/testis barriers. As expected, the toxicokinetics of MPs is significantly size-dependent in mammals.
Male ; Animals ; Mice ; Microplastics ; Plastics ; Genitalia ; Adipose Tissue ; Polystyrenes/toxicity* ; Nerve Tissue ; Mammals

Biological Products ; Compliance ; Ice ; Incubators ; Methods ; Polyethylene ; Polypropylenes ; Polystyrenes ; Product Packaging ; Refrigeration ; Transportation ; Vaccines

BACKGROUND AND OBJECTIVES: Colonization of microorganisms on pollutants is the first indication of the potential ability of microbes to utilize plastic pollutants as a carbon source by sequential biodegradation into usable form for sustenance. The Philippines is considered the third highest country contributing to global mismanaged plastic waste. To locally manage and find a natural and innovative solution to this worldwide concern, this study aimed to evaluate the capacity of Xylaria sp. SDM (sterile dark mycelia) wild type, which was previously reported to colonize polyethylene plastic and mutant strains to colonize polystyrene, a plastic pollutant widely produced in the world. Assessment of the ability of local Xylaria sp. strains to grow, penetrate, and damage the surface and inner structures of polystyrene was investigated using scanning electron microscopy (SEM).

METHODOLOGY: Xylaria sp. strains were cultured in a pH 5.0 mineral medium with 0.5% glucose as carbon source and polystyrene as a co-carbon source, and stored at 25?C for 50 days. At the end of the incubation period, due to irremovable fungal strains on the surface of the polystyrene strips, samples of polystyrene from each strain were subjected to SEM.

RESULTS: On the 20th day of incubation, the presence of mucilaginous sheaths and fungal growth was observed on the surface of treated polystyrene strips. At the end of the 50-day incubation period, scanning electron microscopy (SEM) confirmed fungal growth and colonization, through the presence of mycelial mats and hyphae, of the wild type and mutant strains on the surface and inner structures of polystyrene except the control. Moreover, physical surface damage in the form of holes, cracks, and crevices on polystyrene demonstrated the active burrowing action of Xylaria sp. strains further supporting the potential of this fungus to damage polystyrene plastic.

CONCLUSION: Whereas fungal growth on a polymer surface is necessary but not sufficient to conclude the process of carbon assimilation as the final biodegradation step, the initial colonization of Xylaria sp. strains on polystyrene supports its ability to establish itself and physically damage the pollutant. Hence, this study extended the existing knowledge on the colonizing ability of Xylaria sp. on plastic making it a potential candidate organism to biodegrade plastic waste, which is one of the topmost environmental waste hazards in the world today.

Polystyrenes ; Plastics ; Microscopy, Electron, Scanning

The purpose of our study is to compare the adhesion and biofilm formation abilities of isolates from water discharged from dental unit waterlines (DUWLs). Bacteria were isolated from a total of 15 DUWLs. Twelve isolates were selected for the experiment. To confirm the adhesion ability of the isolates, each isolate was attached to a glass coverslip using a 12-well plate. Plates were incubated at 26℃ for 7 days, and the degree of adhesion of each isolate was scored. To verify the biofilm formation ability of each isolate, biofilms were allowed to form on a 96-well polystyrene flat-bottom microtiter plate. The biofilm accumulations of all isolates formed at 26℃ for 7 days were identified and compared. A total of 56 strains were isolated from 15 water samples including 12 genera and 31 species. Of the 56 isolates, 12 isolates were selected according to the genus and used in the experiment. Sphingomonas echinoides, Methylobacterium aquaticum, and Cupriavidus pauculus had the highest adhesion ability scores of +3 among 12 isolates. Among these three isolates, the biofilm accumulation of C. pauculus was the highest and that of S. echinoides was the third-most abundant. The lowest biofilm accumulations were identified in Microbacterium testaceum and M. aquaticum. Most isolates with high adhesion ability also exhibited high biofilm formation ability. Analysis of adhesion and biofilm formation of the isolates from DUWLs can provide useful information to understand the mechanism of DUWL biofilm formation and development.
Bacteria* ; Bacterial Adhesion ; Biofilms* ; Cupriavidus ; Glass ; Infection Control, Dental ; Methylobacterium ; Polystyrenes ; Sphingomonas ; Water ; Water Microbiology

The purpose of this study is to investigate the correlation of cell surface hydrophobicity (CSH) and biofilm formation or adhesion in Candida albicans (C. albicans) and several pathogenic bacteria. All of C. albicans (n=82) and 7 bacterial species (Escherichia coli, n=25; Klebsiella pneumoniae, n=33; Morganella morganii, n=21; Proteus mirabilis, n=33; Proteus vulgaris, n=12; Pseudomonas aeruginosa, n=31; Staphylococcus aureus, n=31) were isolated clinically. CSH was quantified with microbial adhesion to hydrocarbons. Biofilm formation was determined by tetrazolium salt reduction assay. Adhesion assay was performed by counting colonies after culture the microbes adhered to HeLa cells. Although high CSH-expressing bacterial species showed greater adherence to HeLa cells and larger amounts of biofilm formation on polystyrene, the significant relationships within same species were not shown. In C. albicans, however, strong positive correlations were observed between CSH and biofilm formation (r =0.708; p < 0.05) or cell adhesion (r =0.509; p < 0.05). These results suggest that hydrophobic force of bacteria may play a minor role in adhesion and biofilm formation, but CSH of C. albicans may be an important factor for adherence on surface and biofilm forming process.
Bacteria ; Biofilms* ; Candida albicans* ; Candida* ; Cell Adhesion ; HeLa Cells ; Humans ; Hydrocarbons ; Hydrophobic and Hydrophilic Interactions* ; Klebsiella pneumoniae ; Morganella morganii ; Polystyrenes ; Proteus mirabilis ; Proteus vulgaris ; Pseudomonas aeruginosa ; Staphylococcus aureus

PURPOSE: The goal of this study was to develop and validate a standardized in vitro pathogenic biofilm attached onto saliva-coated surfaces. METHODS: Fusobacterium nucleatum (F. nucleatum) and Porphyromonas gingivalis (P. gingivalis) strains were grown under anaerobic conditions as single species and in dual-species cultures. Initially, the bacterial biomass was evaluated at 24 and 48 hours to determine the optimal timing for the adhesion phase onto saliva-coated polystyrene surfaces. Thereafter, biofilm development was assessed over time by crystal violet staining and scanning electron microscopy. RESULTS: The data showed no significant difference in the overall biomass after 48 hours for P. gingivalis in single- and dual-species conditions. After adhesion, P. gingivalis in single- and dual-species biofilms accumulated a substantially higher biomass after 7 days of incubation than after 3 days, but no significant difference was found between 5 and 7 days. Although the biomass of the F. nucleatum biofilm was higher at 3 days, no difference was found at 3, 5, or 7 days of incubation. CONCLUSIONS: Polystyrene substrates from well plates work as a standard surface and provide reproducible results for in vitro biofilm models. Our biofilm model could serve as a reference point for studies investigating biofilms on different surfaces.
Bacterial Adhesion ; Biofilms ; Biomass ; Fusobacterium nucleatum ; Fusobacterium ; Gentian Violet ; In Vitro Techniques ; Microscopy, Electron, Scanning ; Polystyrenes ; Porphyromonas gingivalis ; Porphyromonas

PURPOSE: The entry of bacteria or harmful substances through the epithelial seal of human gingival keratinocytes (HGKs) in the junctional epithelium (JE) is blocked by specialized intercellular junctions such as E-cadherin junctions (ECJs). However, the influence of roughened substrates, which may occur due to apical migration of the JE, root planing, or peri-implantitis, on the development of the ECJs of HGKs remains largely unknown. METHODS: HGKs were cultured on substrates with varying levels of roughness, which were prepared by rubbing hydrophobic polystyrene dishes with silicon carbide papers. The activity of c-Jun N-terminal kinase (JNK) was inhibited with SP600125 or by transfection with JNK short hairpin RNA. The development of intercellular junctions was analyzed using scanning electron microscopy or confocal laser scanning microscopy after immunohistochemical staining of the cells for E-cadherin. The expression level of phospho-JNK was assessed by immunoblotting. RESULTS: HGKs developed tight intercellular junctions devoid of wide intercellular gaps on smooth substrates and on rough substrates with low-nanometer dimensions (average roughness [Ra]=121.3±13.4 nm), although the ECJs of HGKs on rough substrates with low-nanometer dimensions developed later than those of HGKs on smooth substrates. In contrast, HGKs developed short intercellular junctions with wide intercellular gaps on rough substrates with mid- or high-nanometer dimensions (Ra=505.3±115.3 nm, 867.0±168.6 nm). Notably, the stability of the ECJs was low on the rough substrates, as demonstrated by the rapid destruction of the cell junction following calcium depletion. Inhibition of JNK activity promoted ECJ development in HGKs. JNK was closely associated with cortical actin in the regulation of ECJs in HGKs. CONCLUSIONS: These results indicate that on rough substrates with nanometer dimensions, the ECJs of HGKs develop slowly or defectively, and that this effect can be reversed by inhibiting JNK.
Actins ; Bacteria ; Cadherins* ; Calcium ; Dental Implants ; Epithelial Attachment ; Humans* ; Immunoblotting ; Intercellular Junctions ; JNK Mitogen-Activated Protein Kinases ; Keratinocytes* ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Peri-Implantitis ; Periodontal Diseases ; Polystyrenes ; Re-Epithelialization ; RNA, Small Interfering ; Root Planing ; Silicon ; Transfection

OBJECTIVESTo explore the forensic application value of MPure-12 automatic nucleic acid purification （MPure-12 Method） for DNA extraction by extracting and typing DNA from bloodstains and various kinds of biological samples with different DNA contents.

METHODSNine types of biological samples, such as bloodstains, semen stains, and saliva were collected. DNA were extracted using MPure-12 method and Chelex-100 method, followed by PCR amplification and electrophoresis for obtaining STR-profiles.

RESULTSThe samples such as hair root, chutty, butt, muscular tissue, saliva stain, bloodstain and semen stain were typed successfully by MPure-12 method. Partial alleles were lacked in the samples of saliva, and the genotyping of contact swabs was unsatisfactory. Additional, all of the bloodstains （20 μL, 15 μL, 10 μL, 5 μL, 1 μL） showed good typing results using Chelex-100 method. But the loss of alleles occurred in 1 μL blood volume by MPure-12 method.

CONCLUSIONSMPure-12 method is suitable for DNA extraction of a certain concentration blood samples．Chelex-100 method may be better for the extraction of trace blood samples．This instrument used in nucleic acid extraction has the advantages of simplicity of operator, rapidity, high extraction efficiency, high rate of reportable STR-profiles and lower man-made pollution.

Alleles ; Blood Stains ; Chelating Agents ; DNA/isolation & purification* ; DNA Fingerprinting ; Forensic Medicine/methods* ; Genotype ; Humans ; Male ; Polymerase Chain Reaction/methods* ; Polystyrenes ; Polyvinyls ; Resins, Synthetic ; Saliva ; Semen/chemistry*

The effect of surface charges on the cellular uptake rate and drug release profile of tetrandrine-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (TPNs) was studied. Stabilizer-free nanoprecipitation method was used in this study for the synthesis of TPNs. A typical layer-by-layer approach was applied for multi-coating particles' surface with use of poly(styrene sulfonate) sodium salt (PSS) as anionic layer and poly(allylamine hydrochloride) (PAH) as cationic layer. The modified TPNs were characterized by different physicochemical techniques such as Zeta sizer, scanning electron microscopy and transmission electron microscopy. The drug loading efficiency, release profile and cellular uptake rate were evaluated by high performance liquid chromatography and confocal laser scanning microscopy, respectively. The resultant PSS/PAH/PSS/PAH/TPNs (4 layers) exhibited spherical-shaped morphology with the average size of 160.3±5.165 nm and zeta potential of-57.8 mV. The encapsulation efficiency and drug loading efficiency were 57.88% and 1.73%, respectively. Multi-layer coating of polymeric materials with different charges on particles' surface could dramatically influence the drug release profile of TPNs (4 layers vs. 3 layers). In addition, variable layers of surface coating could also greatly affect the cellular uptake rate of TPNs in A549 cells within 8 h. Overall, by coating particles' surface with those different charged polymers, precise control of drug release as well as cellular uptake rate can be achieved simultaneously. Thus, this approach provides a new strategy for controllable drug delivery.
Antineoplastic Agents, Phytogenic ; administration & dosage ; chemistry ; Benzylisoquinolines ; administration & dosage ; chemistry ; Cell Line, Tumor ; Drug Liberation ; Humans ; Lactic Acid ; chemistry ; Nanoparticles ; adverse effects ; chemistry ; metabolism ; Polyamines ; chemistry ; Polyglycolic Acid ; chemistry ; Polystyrenes ; chemistry ; Static Electricity