Effects of microplastics on the growth, photosynthetic efficiency and nutrient composition in freshwater algae Chlorella vulgaris Beij.

Microplastics, plastic particles and fragments smaller than 5 mm are ubiquitous in various aquatic environments, but the hazards of microplastics with different particle sizes, concentrations and materials are not well understood. This study investigated the toxicity of polyethylene microplastics (PE-MPs) with different concentrations and particle sizes or polystyrene microplastics (PS-MPs) on freshwater algae Chlorella vulgaris Beij (C. vulgaris) for 11 days. Results indicated that the growth, colony formation, photosynthetic pigment contents and soluble intracellular polysaccharides were unaffected, whereas the photosynthetic efficiency and the total soluble protein (TSP) contents were remarkably decreased at 11 d with the increased concentration of PE-MP exposure. The growth, photosynthetic efficiency, soluble intracellular polysaccharides and TSP contents were unaffected after exposure to PE-MPs with different particle sizes or PS-MPs. By contrast, the colony formation and photosynthetic pigment contents were remarkably decreased after exposure to PS-MPs compared with the control or PE-MPs with the same particle size. The C. vulgaris colonization on microplastics was proven by scanning electron microscopy, indicating that the adsorption effects were the main harmful pathways of different microplastics to algal. Our results suggested that microplastics have limited harmful effects on algae, mainly in adsorption and shading.

Epidemiology of Hand, Foot, and Mouth Disease and Genetic Evolutionary Characteristics of Coxsackievirus A10 in Taiyuan City, Shanxi Province from 2016 to 2020.

In recent years, the prevalence of hand, foot, and mouth disease (HFMD) caused by enteroviruses other than enterovirus A71 (EV-A71) and coxsackievirus A16 (CVA16) has gradually increased. The throat swab specimens of 2701 HFMD cases were tested, the VP1 regions of CVA10 RNA were amplified using RT-PCR, and phylogenetic analysis of CVA10 was performed. Children aged 1-5 years accounted for the majority (81.65%) and boys were more than girls. The positivity rates of EV-A71, CVA16, and other EVs were 15.22% (219/1439), 28.77% (414/1439), and 56.01% (806/1439), respectively. CVA10 is one of the important viruses of other EVs. A total of 52 CVA10 strains were used for phylogenetic analysis based on the VP1 region, 31 were from this study, and 21 were downloaded from GenBank. All CVA10 sequences could be assigned to seven genotypes (A, B, C, D, E, F, and G), and genotype C was further divided into C1 and C2 subtypes, only one belonged to subtype C1 and the remaining 30 belonged to C2 in this study. This study emphasized the importance of strengthening the surveillance of HFMD to understand the mechanisms of pathogen variation and evolution, and to provide a scientific basis for HFMD prevention, control, and vaccine development.

Epidemiology of hand, foot, and mouth disease and the genetic characteristics of Coxsackievirus A16 in Taiyuan, Shanxi, China from 2010 to 2021.

Hand, foot, and mouth disease (HFMD) is a common childhood infectious disease caused by human enteroviruses (EV). This study aimed to describe the epidemiological features of HFMD and the genetic characteristics of Coxsackievirus A16 (CVA16) in Taiyuan, Shanxi, China, from 2010 to 2021. Descriptive epidemiological methods were used to analyze the time and population distribution of HFMD and the genetic characteristics of CVA16. Except being affected by the COVID-19 epidemic in 2020, HFMD epidemics were sporadic from January to March each year, and began to increase in April, with a major epidemic peak from May to August, which declined in September, followed by a secondary peak from October to December. The prevalence of EV infection was the highest in children aged one to five years (84.42%), whereas its incidence was very low in children under one year of age (5.48%). Enterovirus nucleic acid was detected by real-time reverse transcription polymerase chain reaction in 6641 clinical specimens collected from patients with HFMD from 2010 to 2021, and 4236 EV-positive specimens were detected, including 988 enterovirus A71 (EV-A71), 1488 CVA16, and 1760 other enteroviruses. CVA16 remains prevalent and has co-circulated with other EVs in Taiyuan from 2010 to 2021. A phylogenetic tree constructed based on the VP1 region showed that all CVA16 strains belonged to two different clades of the B1 genotype, B1a and B1b. They showed a nucleotide similarity of 86.5-100%, and an amino acid similarity of 96.9-100%. Overall, these findings add to the global genetic resources of CVA16, demonstrate the epidemiological characteristics of HFMD as well as the genetic features of CVA16 in Taiyuan City during 2010-2021, and provide supporting evidence for the prevention and control of HFMD.

In vitro biomechanical and biocompatible evaluation of natural hydroxyapatite/chitosan composite for bone repair.

PURPOSE: To evaluate the biomechanical properties and biocompatibility of natural hydroxyapatite/chitosan (HA/CS) composites. METHODS: The natural HA/CS composites with a different proportion of HA and CS were prepared by the cross-linking method, and then the compressive strength, microstructure and pH values of extracts from these composites were measured by SEM and pH meter, respectively. Subsequently, the biocompatibility of the composites was evaluated by means of a series of biological tests, including MTT, acute systemic toxicity, heat source, and hemolysis tests in vitro. RESULTS: The chitosan content in the composites had significantly influenced the mechanical properties and microstructure of the composites. The pH value of the composite extract was approximately 7.0, which was very close to that of human plasma. Furthermore, the natural HA/CS composites showed no cytotoxicity, irritation, teratogenicity, carcinogenicity and special pyrogen. CONCLUSIONS: These results indicated that the natural HA/CS composite may be a potential bone repair material.

Genome-wide pathways analysis of nickel ion-induced differential genes expression in fibroblasts.

To reveal molecular mechanisms of the interaction between Ni2+ and cells, cDNA microarray technology and GenMAPP analysis were utilized to investigate changes of gene expression profile and identify significant biological pathways in mouse fibroblast cells (L-929) treated by 100 microm Ni2+ for 12, 24, 48 and 72 h, respectively. The microarray data was validated by real-time PCR. Methylthiazoltetrazolium (MTT) analysis and flow cytometry experiment were used to assess the cellular response of L-929 cells to Ni2+. It was found that six main biological pathways were affected by Ni2+ with 118 differentially expressed genes involved. Further analysis illuminated that the exposure of cells to Ni2+ may evoke series of cellular responses to hypoxia by regulating hypoxia-inducible gene expression and cause irreversible DNA damage. Cell cycle pathway analysis results showed DNA replication in S phase could be inhibited by Ni2+ which was consistent with the data gained from flow cytometry experiment. Compared to previous researches based on conventional molecular biology experiments, the present work has not only indirectly validated the findings of other groups but also obtained several discoveries related to cell-Ni2+ interaction, such as inhibition of electron transport chain and accumulation of extracellular matrix (ECM) collagens. The routine of the present study not only can analyze gene expression profile but also may provide a more convenient and efficient approach to explain molecular mechanisms of cell-biomaterial interaction.

Studies on the extraction of chromium(III) by emulsion liquid membrane.

This paper presents a comprehensive study on removal of chromium(III) from aqueous waste solution using emulsion liquid membrane (ELM). The study has highlighted the importance of emulsion stability for maximizing the removal of chromium(III). The ELM consists of tri-n-butyl phosphate (TBP) as a carrier, commercial kerosene as organic solvent, sulfonated liquid polybutadiene (LYF) as surfactant agent, sulfuric acid, deionized water or sodium hydroxide as stripping phase. The important factors studied which affected the ELM stability and removal of chromium(III) were the concentrations of surfactant (2-8% w/w), carrier (2-10% w/w), internal phase H(2)SO(4) [pH 0-6], deionized water [pH 6.65] and NaOH (0-0.8% w/w), transfer time (5-35 min) and the effect of volume ratio of the feed solution to the emulsion phase (Rf) (5:1-9:1). At the optimum condition it was possible to remove 99.71-99.83% of chromium(III) by using ELM. LYF was not only the surfactant but also played a key auxiliary effect for TBP combining with chromium(III) by studying on the transport mechanism.