Responses of submerged macrophytes to different particle size microplastics and tetracycline co-pollutants at the community and population level.

Microplastics (MPs) and antibiotics are ubiquitous in aquatic ecosystems, and their accumulation and combined effects are considered emerging threats that may affect biodiversity and ecosystem function. The particle size of microplastics plays an important role in their combined effects with antibiotics. Submerged macrophytes are crucial in maintaining the health and stability of freshwater ecosystems. However, little is known about the combined effects of different particle size of MPs and antibiotics on freshwater plants, particularly their effects on submerged macrophyte communities. Thus, there is an urgent need to study their effects on the macrophyte communities to provide essential information for freshwater ecosystem management. In the present study, a mesocosm experiment was conducted to explore the effects of three particle sizes (5 µm, 50 µm, and 500 µm) of polystyrene-microplastics (PSMPs) (75 mg/L), tetracycline (TC) (50 mg/L), and their co-pollutants on interactions between Hydrilla verticillata and Elodea nuttallii. Our results showed that the effects of MPs are size-dependent on macrophytes at the community level rather than at the population level, and that small and medium sized MPs can promote the growth of the two test macrophytes at the community level. In addition, macrophytes at the community level have a stronger resistance to pollutant stress than those at the population level. Combined exposure to MPs and TC co-pollutants induces species-specific responses and antagonistic toxic effects on the physio-biochemical traits of submerged macrophytes. Our study provides evidence that MPs and co-pollutants not only affect the morphology and physiology at the population level but also the interactions between macrophytes. Thus, there are promising indications on the potential consequences of MPs and co-pollutants on macrophyte community structure, which suggests that future studies should focus on the effects of microplastics and their co-pollutants on aquatic macrophytes at the community level rather than only at the population level. This will improve our understanding of the profound effects of co-pollutants in aquatic environments on the structure and behavior of aquatic communities and ecosystems.

Cellulose de-polymerization is selective for bioethanol refinery and multi-functional biochar assembly using brittle stalk of corn mutant.

As lignocellulose recalcitrance principally restricts for a cost-effective conversion into biofuels and bioproducts, this study re-selected the brittle stalk of corn mutant by MuDR-transposon insertion, and detected much reduced cellulose polymerization and crystallinity. Using recyclable CaO chemical for biomass pretreatment, we determined a consistently enhanced enzymatic saccharification of pretreated corn brittle stalk for higher-yield bioethanol conversion. Furthermore, the enzyme-undigestible lignocellulose was treated with two-step thermal-chemical processes via FeCl2 catalysis and KOH activation to generate the biochar with significantly raised adsorption capacities with two industry dyes (methylene blue and Congo red). However, the desirable biochar was attained from one-step KOH treatment with the entire brittle stalk, which was characterized as the highly-porous nanocarbon that is of the largest specific surface area at 1697.34 m2/g and 2-fold higher dyes adsorption. Notably, this nanocarbon enabled to eliminate the most toxic compounds released from CaO pretreatment and enzymatic hydrolysis, and also showed much improved electrochemical performance with specific capacitance at 205 F/g. Hence, this work has raised a mechanism model to interpret how the recalcitrance-reduced lignocellulose is convertible for high-yield bioethanol and multiple-function biochar with high performance.

Microplastics and co-pollutant with ciprofloxacin affect interactions between free-floating macrophytes.

Microplastic and antibiotic contamination are considered an increasing environmental problem in aquatic systems, while little is known about the impact of microplastics and co-pollutant with antibiotics on freshwater vascular plants, particularly the effects of interactions between macrophytes. Here, we performed a mesocosm experiment to evaluate the impact of polyethylene-microplastics and their co-pollutants with ciprofloxacin on the growth and physiological characteristics of Spirodela polyrhiza and Lemna minor and the interactions between these two macrophytes. Our results showed that microplastics alone cannot significantly influence fresh weight and specific leaf area of the two test free-floating macrophytes, but the effects on photosynthetic pigments, malondialdehyde, catalase and soluble sugar contents were species-specific. Ciprofloxacin can significant adverse effects on the growth and physiological traits of the two test macrophytes and microplastic mitigated the toxicity of ciprofloxacin on the two free-floating plants to a certain extent. In addition, our studies showed that microplastics and co-pollutants can influence relative yield and competitiveness of S. polyrhiza and L. minor by directly or indirectly influencing their physiology and growth. Therefore our findings suggest that species-specific sensibility to microplastic and its co-pollutant among free-floating macrophytes may influence macrophyte population dynamics and thereby community structure and ecosystem functioning. And microplastics altered other contaminant behaviours and toxicity, and may directly or indirectly influence macrophytes interactions and community structure. The present study is the first experimental study exploring the effects of microplastics alone and with their co-pollutants on interactions between free-floating macrophytes, which can provide basic theoretical guidance for improving the stability of freshwater ecosystems.

Sensory Features of Partially Hydrogenated Oil and Their Connection with Melting and Crystalline Characteristics.

Although partially hydrogenated oil (PHO) provides foods with outstanding thick tastes and pronounced "creamy" flavor, the high level of artificial trans-fatty acids (TFA; about 30%) limits its usages around the world in the near future. It is necessary to produce trans-free alternatives with similar tastes to PHO. The relationship between sensory attributes and physicochemical characteristics of PHO and four typical specialty fats were therefore analyzed in the present study. PHO exhibited the highest greasiness score (8.19), accompanying by mild creaminess and aftertaste as well as a weak coolness during swallow, which were resulted from the close-packed arrangements of TFA, its cis-counterparts and other long chain fatty acids. None of artificial trans-fats, mainly anhydrous milk fat, cocoa butter, and coconut oil and its fully hydrogenated counterpart, were similar to PHO in terms of these sensory attributes. The unique fatty acid species of PHO and their arrangements contributed to the relatively smooth solid fat content profile and melting-crystallization curve, as well as forming uniform and dense ß' crystal-structures (Db=1.80). The Pearson correlation analyses relevelled that long chain fatty acids, e.g., t-C18:1 and C18:1, and melting final temperatures were generally positive correlated with greasiness, creaminess and aftertaste; whereas these indices were negatively correlated with coolness. The melting enthalpy was highly connected with coolness, which reflected the endothermic effectiveness during the melting process of fats in the mouth. These indices screened by correlation analyses that were strongly correlated with sensory attributes could provide references for producing trans-free alternatives.

Characteristics and molecular mechanism of adhesion proteins on reused hemodialysis membranes.

In order to study the mechanism of protein adhesion on the Fresenius F6 polysulfone membrane dialyzer, two-dimensional gel electrophoresis, LC-ESI-MS/MS and bioinformatics methods were used to analyze the protein which adhered to the dialyzer membrane. Six of the adhered proteins account for more than 50% of the total 179 proteins, i.e. ficolin precursor, complement C3 precursor, 3 variants of MASP1 and albumin. The results also showed that easily adhered proteins have a greater percentage of acidic amino acids (p < 0.01). The isoelectric point of the 20 proteins with the most deposits is 6.2 +/- 1.08, which is obviously lower than of those with the least deposits (7.56 +/- 1.36, p < 0.01). The dipole moment of a polysulfone membrane molecule has a tendency to absorb molecules with a negative charge. These results are of significance in understanding and improving membrane protein interactions.

[Species and characteristics of protein adsorption on reused hemodialysis membranes].

The aim of this study was to systemically analyze the proteins that adsorbed on the surface of hemodialysis membrane. The Fresenius F6 reused polysulfone dialyzers were selected as the research objects. The methodology we used encompassed the digestion of protein in rinsed solution and the separation of peptide mixture in virtue of RP-HPLC followed by ESI-MS/MS identification in orde to get their adsorption behavior, species and characteristics. The results illustrated that, after being rinsed by reverse osmosis (RO) water, 179 species of the protein adsorbed on the hemodialysis membrane, most of which were acidulous and middle or small weight protein molecules. The data from counting the numbers of peptides showed there were 5 species of high-abundant proteins (the contents being above 5% each), namely Ficolin-2 precursor, Complement C3 precursor (Fragment), Mannan-binding lectin serine protease 1 isoform 2 precursor, Complement-activating component of Ra-reactive factor precursor, and Mannan-binding lectin serine protease 1 isoform 3. These proteins are in close relationship with human immune system; moreover, they are of great significance to the clinical mechanism for cleaning reuse hemodialyzers and to the development of new hemodialysis materials.

[Ingredients of membrane adhesion in reused dialyzer].

Selecting reused polysulfone membrane (PSM) dialyzers as research objects, we mainly analyzed quantitatively the adhesion ingredients which obstructed the passage through the membrane, and we investigated the differences of residual contaminants on the surface of PSM in the cases of various reuse times. The results illustrated that after the completion of dialysis, the dialyzer was first cleaned by reverse osmosis (RO) water to remove the protein adsorpted. Then we used 2% sodium hypochlorite (NaClO) solution to soak it, and the glucose, cholesterol and triglyceride adsorpted were dissolved off. Meanwhile, the quantity of most of adsorption gradually increased with the increase of reuse times.