Determination of utilization strategies for hemihydrate phosphogypsum in cemented paste backfill: Used as cementitious material or aggregate.

Due to the prominent advantages of low cost and efficient utilization, cemented hemihydrate phosphogypsum (HPG) backfill is becoming popular in mine goaf treatments in China as a new promising branch of cemented paste backfill (CPB). The HPG gelling activity time dependence determines its role in CPB, that is, whether it is used as a cementitious material or aggregate. Laboratory and field experiments showed that the HPG gelling activity decreases with an increasing aging time due to the gradual HPG conversion from the hemihydrate to the dihydrate form. The HPG conversion can be described by the Avrami equation, and further divided into acceleratory and slow reaction periods. Soluble P2O5 formed insoluble brushite coatings, significantly inhibiting the HPG conversion. Increasing the Al2O3 content and reducing temperature further retarded the HPG conversion. Reducing the temperature inside the stacks by lowering their stacking height delayed the HPG gelling activity decay. At a stacking height of 1.5 m, HPG can be prepared into cementitious materials for common CPB methods within the first 137 h of aging, thereafter it can only be used as an inactive aggregate. Finally, an application case is presented to illustrate the effectiveness of the utilization strategies in guiding the use of HPG in CPB.

Integrative transcriptomic and metabolomic analyses provide insight into the long-term submergence response mechanisms of young Salix variegata stems.

MAIN CONCLUSION: The mechanisms underlying long-term complete submergence tolerance in S. variegata involve enhanced oxidative stress responses, strengthened ethylene and ABA signaling, synthesis of raffinose family oligosaccharides, unsaturated fatty acids, and specific stress-related amino acids. Salix variegata Franch. is a riparian shrub species that can tolerate long-term complete submergence; however, the molecular mechanisms underlying this trait remain to be elucidated. In this study, we subjected S. variegata plants to complete submergence for 60 d and collected stems to perform transcriptomic and metabolomic analyses, as well as quantitative reverse transcription-polymerase chain reaction (qRT-PCR) assays. Results revealed that photosynthesis and the response to light stimulus were inhibited during submergence and recovered after desubmergence. Ethylene and abscisic acid (ABA) signaling could be important for the long-term submergence tolerance of S. variegata. Jasmonic acid (JA) signaling also participated in the response to submergence. Raffinose family oligosaccharides, highly unsaturated fatty acids, and specific stress-related amino acids accumulated in response to submergence, indicating that they may protect plants from submergence damage, as they do in response to other abiotic stressors. Several organic acids were produced in S. variegata plants after submergence, which may facilitate coping with the toxicity induced by submergence. After long-term submergence, cell wall reorganization and phenylpropanoid metabolic processes (the synthesis of specific phenolics and flavonoids) were activated, which may contribute to long-term S. variegata submergence tolerance; however, the detailed mechanisms require further investigation. Several transcription factors (TFs), such as MYB, continuously responded to submergence, indicating that they may play important roles in the responses and adaption to submergence. Genes related to oxidative stress tolerance were specifically expressed after desubmergence, potentially contributing to recovery of S. variegata plants within a short period of time.

Echinococcus shiquicus in Qinghai-Tibet plateau: population structure and confirmation of additional endemic areas.

Echinococcus shiquicus is currently limited to the Qinghai­Tibet plateau, a large mountainous region in China. Although the zoonotic potential remains unknown, progress is being made on the distribution and intermediate host range. In this study, we report E. shiquicus within Gansu and Qinghai provinces in regions located not only around the central areas but also the southeast edge of the plateau and describe their genetic relationship with previous isolates from the plateau. From 1879 plateau pikas examined, 2.39% (95% CI 1.79­3.18) were infected with E. shiquicus. The highest prevalence of 10.26% (4.06­23.58) was recorded in Makehe town, Qinghai province. Overall the prevalence was marginally higher in Qinghai (2.5%, CI 1.82­3.43) than in Gansu (2%, CI 1.02­3.89). The cox1 and nad1 genes demonstrated high and low haplotype and nucleotide diversities, respectively. The median-joining network constructed by the cox1­nad1 gene sequences demonstrated a star-like configuration with a median vector (unsampled haplotype) occupying the centre of the network. No peculiar distinction or common haplotype was observed in isolates originating from the different provinces. The presence of E. shiquicus in regions of the southeast and northeast edges of the Qinghai­Tibet plateau and high genetic variation warrants more investigation into the haplotype distribution and genetic polymorphism by exploring more informative DNA regions of the mitochondrial genome to provide epidemiologically useful insight into the population structure of E. shiquicus across the plateau and its axis.

miR319a/TCP module and DELLA protein regulate trichome initiation synergistically and improve insect defenses in Populus tomentosa.

Trichomes are specialized epidermal cells that contribute to plant resistance against herbivores. Their formation is controlled precisely by multiple genetic and environmental signals. Previous studies have shown that microRNA319 (miR319) and gibberellin (GA) signaling are involved in trichome development in Arabidopsis, but little is known about their interaction between these factors. Here we reported that the miR319a/TEOSINTE BRANCHED/CYCLOIDEA/PCF (TCP) module participates in trichome initiation synergistically with GA signaling in Populus tomentosa. We demonstrated that overexpression of miR319a decreased transcription levels of its targeted TCPs and significantly elevated leaf trichome density in transgenic poplar, resulting in decreasing insect herbivory. Conversely, repressing miR319a by short tandem target mimics (STTM) elevated TCP expression levels and decreased trichome density in transgenic plants. The trichome phenotype of 35S:miR319a plants could be abolished by introducing a miR319a-resistant form of TCP19. Furthermore, the miR319a-targeted TCP19 interacted directly with REPRESSOR OF ga1-3 (RGA), a downstream repressor of GA signaling. TCP19 and RGA synergistically inhibited the GLABROUS1 (GL1)-induced expression of trichome marker gene GLABRA2 (GL2), thereby repressing leaf trichome initiation. Our results provide an insight into the molecular mechanism by which miR319/TCP19 module and GA signaling coordinated regulating trichome initiation in P. tomentosa.

MicroRNA6443-mediated regulation of FERULATE 5-HYDROXYLASE gene alters lignin composition and enhances saccharification in Populus tomentosa.

Ferulate 5-hydroxylase (F5H) is a limiting enzyme involved in biosynthesizing sinapyl (S) monolignol in angiosperms. Genetic regulation of F5H can influence S monolignol synthesis and therefore improve saccharification efficiency and biofuel production. To date, little is known about whether F5H is post-transcriptionally regulated by endogenous microRNAs (miRNAs) in woody plants. Here, we report that a microRNA, miR6443, specifically regulates S lignin biosynthesis during stem development in Populus tomentosa. In situ hybridization showed that miR6443 is preferentially expressed in vascular tissues. We further identified that F5H2 is the direct target of miR6443. Overexpression of miR6443 decreased the transcript level of F5H2 in transgenic plants, resulting in a significant reduction in S lignin content. Conversely, reduced miR6443 expression by short tandem target mimics (STTM) elevated F5H2 transcripts, therefore increasing S lignin composition. Introduction of a miR6443-resistant form of F5H2 into miR6443-overexpression plants restored lignin ectopic composition, supporting that miR6443 specifically regulated S lignin biosynthesis by repressing F5H2 in P. tomentosa. Furthermore, saccharification assays revealed decreased hexose yields by 7.5-24.5% in miR6443-overexpression plants compared with the wild-type control, and increased hexoses yields by 13.2-14.6% in STTM6443-overexpression plants. Collectively, we demonstrate that miR6443 modulates S lignin biosynthesis by specially regulating F5H2 in P. tomentosa.

MiR319a-targeted PtoTCP20 regulates secondary growth via interactions with PtoWOX4 and PtoWND6 in Populus tomentosa.

Secondary growth is a key characteristic of trees, which requires the coordination of multiple regulatory mechanisms including transcriptional regulators and microRNAs (miRNAs). However, the roles of microRNAs in the regulation of secondary growth need to be explored in depth. Here, the role of miR319a and its target, PtoTCP20, in the secondary growth of Populus tomentosa stem was investigated using genetic and molecular analyses. The expression level of miR319a gradually decreased from primary to secondary growth in P. tomentosa, while that of PtoTCP20 gradually increased. MiR319a overexpression in seedlings resulted in delayed secondary growth and decreased xylem production, while miR319a knockdown and PtoTCP20 overexpression promoted secondary growth and increased xylem production. Further analysis showed that PtoTCP20 interacted with PtoWOX4a and activated PtoWND6 transcription in vitro and in vivo. Our data show that PtoTCP20 controls vascular cambium proliferation by binding to PtoWOX4a, and promotes secondary xylem differentiation by activating PtoWND6 transcription, thereby regulating secondary growth in P. tomentosa. Our findings provide insight into the molecular mechanisms underlying secondary growth in trees.

Diagnosis and therapeutic monitoring of inborn errors of metabolism in 100,077 newborns from Jining city in China.

BACKGROUND: Mandatory newborn screening for metabolic disorders has not been implemented in most parts of China. Newborn mortality and morbidity could be markedly reduced by early diagnosis and treatment of inborn errors of metabolism (IEM). Methods of screening for IEM by tandem mass spectrometry (MS/MS) have been developed, and their advantages include rapid testing, high sensitivity, high specificity, high throughput, and low sample volume (a single dried blood spot). METHODS: Dried blood spots of 100,077 newborns obtained from Jining city in 2014-2015 were screened by MS/MS. The screening results were further confirmed by clinical symptoms and biochemical analysis in combination with the detection of neonatal deficiency in organic acid, amino acid, or fatty acid metabolism and DNA analysis. RESULTS: The percentages of males and females among the 100,077 infants were 54.1% and 45.9%, respectively. Cut-off values were established by utilizing the percentile method. The screening results showed that 98,764 newborns were healthy, and 56 out of the 1313 newborns with suspected IEM were ultimately diagnosed with IEM. Among these 56 newborns, 19 (1:5267) had amino acid metabolism disorders, 26 (1:3849) had organic acid metabolism disorders, and 11 (1:9098) had fatty acid oxidation disorders. In addition, 54 patients with IEM were found to carry mutations, and the other 2 patients had argininemia. CONCLUSIONS: Fifty-six cases of metabolic disorders in Jining were confirmed via newborn screening (NBS) by MS/MS. Early diagnosis and treatment are crucial for the survival and well-being of affected children. A nationwide NBS program using MS/MS is recommended, especially in poor areas of China.

Segmental relaxation behavior of polystyrene chains in the cores of collapsed dry micelles tethered on the micelle film surface by a poly(acrylic acid) corona.

We present an experimental investigation of the segmental relaxation behavior of polystyrene (PS) chains that are confined in a micellar core tethered by a poly(acrylic acid) (PAA) block corona on the dry film surface, along with various core density and molecular weight of PS block from below to well above the entanglement molecular weight. The results show that the onset temperature of PS chain rearrangement (T(onset)), which was much lower than the T(bulk)(g) of the corresponding PS block and higher than T(film)(g) of ultrathin PS films with corresponding thickness and molecular weights, generally increases with increasing density of the micelle core. It was found that the difference in ΔT(onset) with increasing relative density ρ/ρmin obtained from PS154-b-PAA49 and PS278-b-PAA47 micelles was large, while these from PS278-b-PAA47 and PS404-b-PAA63 was negligible, suggesting that entanglement has considerable influence on the density dependence of the T(onset) of PS chains under confinement in the micelle core on the film surface.

Mechanical Stretch α-Cyclodextrin Pseudopolyrotaxane Elastomer with Reversible Phosphorescence Behavior.

Polyethylene glycol chains in two terminals of the naphthalene functional group are threaded into α-cyclodextrin cavities to form the pseudopolyrotaxane (NPR), which not only effectively induces the phosphorescence of the naphthalene functional group by the cyclodextrin macrocycle confinement, but also provides interfacial hydrogen bonding assembly function between polyhydroxy groups of cyclodextrin and waterborne polyurethane (WPU) chains to construct elastomers. The introduction of NPR endows the elastomer with enhanced mechanical properties and excellent room temperature phosphorescent (RTP) emission (phosphorescence remains in water, acid, alkali, and organic solvents, even at 160 °C high temperatures). Especially, the reversible mechanically responsive room temperature phosphorescence behavior (phosphorescence intensity increased three times under 200% strain) can be observed in the mechanical stretch and recover process, owing to strain-induced microstructural changes further inhibiting the non-radiative transition and the vibration of NPR. Therefore, changing the phosphorescence behavior of supramolecular elastomers through mechanical stretching provides a new approach for supramolecular luminescent materials.

Water/Light Multiregulated Supramolecular Polypseudorotaxane Gel with Switchable Room-Temperature Phosphorescence.

Water/light regulated room-temperature phosphorescence (RTP) of polypseudorotaxane supramolecular gel is constructed by threading the poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEG-PPG-PEG) chain with the bromoaromatic aldehyde into mono-(6-ethylenediamine-6-deoxygenated)-ß-cyclodextrin (ECD) cavities and further assembling with negatively charged Laponite XLG (CNS) and diarylethene derivative (DAE) through electrostatic interaction. This hydrogel exhibits significant blue fluorescence emission; instead, after lyophilization to xerogel, the system exhibits both blue fluorescence and yellow RTP based on the rigid network structure of the xerogel, which restricts the vibration of the phosphor and suppresses the nonradiative relaxation process. Interestingly, the addition of excess ECDs to the gel system can enhance the RTP emission. Furthermore, the reversible luminescence behavior can be adjusted by the photoresponsive isomerism of DAE and humidity. This polypseudorotaxane supramolecular gel system provides a novel strategy for constructing tunable RTP materials.

Recycling of phosphate tailings for an efficient hydroxyapatite-based adsorbent to immobilize heavy metal cations.

Hydroxyapatite (HAP) is a promising adsorbent for immobilizing heavy metals in soil and water. However, the preparation and modification of HAP from pure chemicals increases its cost and limits its large-scale practical application. In this study, a hydroxyapatite-based adsorbent (HAPPT) was prepared from phosphate tailing produced in the phosphorus industry to sequester Pb, Cd and Zn from solution. The results showed that HAPPT was composed of HAP and MgO, with a surface area of 27.74 m2/g. The kinetics studies showed that most Pb and Cd were removed from the initial solution in 4 h and the adsorption of Zn increased with increasing contact time. Metals presented higher adsorption capacities at 35 °C than that at 25 °C. The adsorption isotherms showed that HAPPT presented high adsorption capacities for Pb, Cd and Zn in mono-metal solutions. The adsorption capacity of Cd at pH 6 was higher than that at pH 3, but the adsorption for Pb and Zn was similar at both pHs. HAPPT has selectivity for Pb in Pb-Cd-Zn multi-metals solution, and competitive adsorption reduced the adsorption quantity by 53%, 93% and 79% for Pb, Cd and Zn, respectively. The combined results of TEM-EDS, XRD and XPS showed that Pb was immobilized by forming phosphates due to the dissolution of HAP, whereas Cd and Zn were immobilized by forming hydroxide precipitates resulting from the function of MgO in HAPPT. The results of this study provided an efficient adsorbent for the removal of heavy metals in solution and provided a new perspective on the recycling of phosphate tailings in the phosphorus industry.

Adjuvant effect of ginsenoside-based nanoparticles (ginsomes) on the recombinant vaccine against Eimeria tenella in chickens.

An experiment was conducted to study the adjuvant effect of ginsomes on the recombinant profilin in coccidian-infected breeding birds. Three-day-old chickens were vaccinated with Eimeria tenella recombinant profilin antigen (10, 50, and 100 µg per chicken) with or without 50 µg ginsomes per chicken. The boost vaccination was carried out 14 days later. Two weeks after the booster, the chickens were challenged with 1.5 × 10(4) homologous sporulated oocysts. The specific antibody response, lymphocyte proliferation, and IL-1 release from lymphocyte were measured at 1-42 days after boost vaccination. Seven days post-challenge, the rate of survival, body weight gains (BWG) were examined then all chickens were sacrificed and lesion scores and oocysts per gram were monitored to evaluate the protective effects of the vaccination after challenge. Compared with the group of vaccinating with profilin only, groups of 50 and 100 µg antigen plus ginsomes significantly enhanced lymphocyte proliferation and IL-1 secretion. The profilin specific antibody level in the four vaccinated groups was significantly higher than in the control group and in groups vaccinated with profilin containing ginsomes than profilin only. In the groups vaccinated with profilin plus ginsomes, the BWG was significantly higher than that of group of profilin only, but there was no significant difference between profilin plus adjuvant ginsomes, diclazuril medicated and uninfected-unmedicated-unvaccinated control groups. The lesion scores in groups immunized with profilin plus ginsomes was significantly lower than that both of groups unimmunized-challenged-unmedicated control and group vaccinated with profilin only. Oocyst excretion in groups vaccinated with 50 or 100 µg profilin plus ginsomes was lower than that of groups vaccinated with profilin only. These results demonstrate that the adjuvant ginsomes can promote subunit vaccine to induce a strong immune response and protective effects.

Fabrication of Metallic Superhydrophobic Surfaces with Tunable Condensate Self-Removal Capability and Excellent Anti-Frosting Performance.

Laser fabrication of metallic superhydrophobic surfaces (SHSs) for anti-frosting has recently attracted considerable attention. Effective anti-frosting SHSs require the efficient removal of condensed microdroplets through self-propelled droplet jumping, which is strongly influenced by the surface morphology. However, detailed analyses of the condensate self-removal capability of laser-structured surfaces are limited, and guidelines for laser processing parameter control for fabricating rationally structured SHSs for anti-frosting have not yet been established. Herein, a series of nanostructured copper-zinc alloy SHSs are facilely constructed through ultrafast laser processing. The surface morphology can be properly tuned by adjusting the laser processing parameters. The relationship between the surface morphologies and condensate self-removal capability is investigated, and a guideline for laser processing parameterization for fabricating optimal anti-frosting SHSs is established. After 120 min of the frosting test, the optimized surface exhibits less than 70% frost coverage because the remarkably enhanced condensate self-removal capability reduces the water accumulation amount and frost propagation speed (<1 µm/s). Additionally, the material adaptability of the proposed technique is validated by extending this methodology to other metals and metal alloys. This study provides valuable and instructive insights into the design and optimization of metallic anti-frosting SHSs by ultrafast laser processing.

C1q/TNF-related protein 9 decreases cardiomyocyte hypoxia/reoxygenation-induced inflammation by inhibiting the TLR4/MyD88/NF-κB signaling pathway.

C1q/TNF-related protein 9 (CTRP9) acts as an adipokine and has been reported to exert numerous biological functions, such as anti-inflammatory and anti-oxidative stress effects, in ischemic heart disease. In the present study, the role of CTRP9 in neonatal rat cardiomyocytes (NRCMs) following hypoxia/reoxygenation (H/R) and the underlying mechanism was investigated. Adenoviral vectors containing CTRP9 or green fluorescent protein were transfected into NRCMs. A H/R model was constructed 2 days after transfection by 2 h incubation under hypoxia followed by 4 h of reoxygenation. Lactate dehydrogenase (LDH), creatine kinase (CK) and CK-myocardial band (CK-MB) levels were detected by a biochemical analyzer using biochemical kits. In addition, cell viability was detected using trypan blue staining to determine the extent of cell injury. Inflammatory cytokines TNF-α, IL-6 and IL-10 were measured by ELISA. Western blotting and reverse transcription-quantitative PCR were used to evaluate the expression levels of CTRP9, toll-like receptor 4 (TLR4), myeloid differentiation primary response (MyD88) and NF-κB. The DNA binding activity of NF-κB was also detected using an electrophoretic mobility shift assay. The results indicated that transfection with adenoviral vectors containing CTRP9 could markedly enhance CTRP9 expression. CTRP9 overexpression increased cell viability and decreased the release of LDH, CK and CK-MB. In addition, CTRP9 overexpression reduced TNF-α and IL-6 levels whilst increasing IL-10 levels, but decreased the expression of TLR4, MyD88 and NF-κB. Furthermore, the DNA binding activity of NF-κB under H/R was also decreased by CTRP9 overexpression. In conclusion, the results of the present study suggested that CTRP9 could protect cardiomyocytes from H/R injury, which was at least partially due to the inhibition of the TLR4/MyD88/NF-κB signaling pathway to reduce the release of inflammatory cytokines.

Infantile Colic Treated With Bifidobacterium longum CECT7894 and Pediococcus pentosaceus CECT8330: A Randomized, Double-Blind, Placebo-Controlled Trial.

Background: Colic is a common condition in infants <4 months of age. Attempts to treat infantile colic with probiotics have shown variable efficacy and overall low evidence of success. In this work, we tested the hypothesis that oral administration of Bifidobacterium longum CECT7894 (KABP042) and Pediococcus pentosaceus CECT8330 (KABP041) mix (1 × 109 colony forming units) would improve the symptoms of infantile colic. Methods: A total of 112 exclusively breastfed or mixed fed infants aged <2 months and meeting the ROME IV criteria for infantile colic were recruited. The infants were randomized in a double-blind, placebo-controlled trial to receive orally administered probiotics (intervention group, IG, n = 48) or placebo (placebo group, PG, n = 42) daily for 21 days. Results: Infants in the IG had significantly shorter crying time (p < 0.001) on day 7 [IG vs. PG, median (25-75th percentile): 38 (3.5-40.5) vs. 62 (40-108) min/day], day 14 [IG vs. PG: 20 (0-40) vs. 50 (30-75) min/day], and day 21 [IG vs. PG: 14 (0-33) vs. 40 (28-62) min/day]. Higher responder ratio and fewer crying/fussing episodes on days 7, 14, and 21 and better stool consistency on day 21 were observed in the IG (p < 0.01) as compared to the PG. Conversely, no significant effects on stool frequency or quality of life were observed. Conclusions: In summary, daily oral administration of B. longum CECT7894 (KABP042) and P. pentosaceus CECT8330 (KABP041) was an effective treatment for shortening crying time due to infantile colic and for improving fecal consistency. This trial was registered retrospectively in December 2019 with a trial number of ISRCTN92431452.

Genetic Evolution and Implications of the Mitochondrial Genomes of Two Newly Identified Taenia spp. in Rodents From Qinghai-Tibet Plateau.

The larva of Taeniidae species can infect a wide range of mammals, causing major public health and food safety hazards worldwide. The Qinghai-Tibet Plateau (QTP), a biodiversity hotspot, is home to many species of rodents, which act as the critical intermediate hosts of many Taeniidae species. In this study, we identified two new larvae of Taenia spp., named T. caixuepengi and T. tianguangfui, collected from the plateau pika (Ochotona curzoniae) and the Qinghai vole (Neodon fuscus), respectively, in QTP, and their mitochondrial genomes were sequenced and annotated. Phylogenetic trees based on the mitochondrial genome showed that T. caixuepengi has the closest genetic relationship with T. pisiformis, while T. tianguangfui was contained in a monophyletic group with T. crassiceps, T. twitchelli, and T. martis. Biogeographic scenarios analysis based on split time speculated that the speciation of T. caixuepengi (∼5.49 Mya) is due to host switching caused by the evolution of its intermediate host. Although the reason for T. tianguangfui (∼13.11 Mya) speciation is not clear, the analysis suggests that it should be infective to a variety of other rodents following the evolutionary divergence time of its intermediate host and the range of intermediate hosts of its genetically close species. This study confirms the species diversity of Taeniidae in the QTP, and speculates that the uplift of the QTP has not only a profound impact on the biodiversity of plants and animals, but also that of parasites.

Pyrolyzed fabrication of N/P co-doped biochars from (NH4)3PO4-pretreated coffee shells and appraisement for remedying aqueous Cr(VI) contaminants.

In this study, an agricultural residue-derived biochar was fabricated by pyrolyzing coffee shells using (NH4)3PO4 pretreatment. The influence of pyrolysis temperature on the structure and properties of biochars was investigated. The elemental analysis, spectroscopic and textural studies showed that the biochars were endued sufficient N and P co-doping and large specific surface area by (NH4)3PO4-pretreatment. The appraisement for remedying aqueous Cr(VI) contaminants demonstrated that the N/P co-doped biochars offered high efficiencies above 95% for aqueous Cr(VI) removal. The mechanism investigation displayed that the adsorption and reduction of Cr(VI) were boosted by the synergistic effect between the hierarchical pore structure and the groups related to oxygen, nitrogen and phosphorus. Moreover, the biochar can be readily regenerated by HCl solution soaking for reuses several times. This work should permit for providing a convenient utilization of coffee shell agricultural residues, and the coffee shell-derived biochars supplied potential for remedying Cr(VI) in effluents.

Coherent toxicity prediction framework for deciphering the joint effects of rare earth metals (La and Ce) under varied levels of calcium and NTA.

With the development of modern technologies, the exploitation and application of rare earth metals (REMs) have increased parallelly. Consequently, more REMs are entering into the environment and therefore there is a pressing need to assess their potential environmental hazards. Here, a standard toxicity test with wheat (Triticum aestivum) was conducted to investigate the single and mixture toxicity of La and Ce in solutions with different levels of calcium and nitrilotriacetic acid (NTA) and results were deciphered by different modeling approaches. Both La and Ce caused adverse effect to wheat, but the presence of Ca and NTA alleviated their toxicity. The obtained EC50 for [La] or [Ce] changed by more than 28-fold and by 4-fold, respectively, with the increase of Ca or NTA. The biotic ligand model (BLM) explained approximately 93% variation of single La or Ce toxicity. The binding constants obtained were 4.14, 6.67, and 6.59 for logKCaBL, logKLaBL, and logKCeBL respectively. The electrostatic toxicity model (ETM) was proved as effective as the BLM, with R2 = 0.93 for La and R2 = 0.92 for Ce. For La-Ce mixtures, parameters from single toxicity approaches were applied successfully to predict the mixture toxicity with concentration addition (CA) model based on the BLM or ETM theory (R2 = 0.92 and RMSE = 8.56; R2 = 0.90 and RMSE = 9.6, respectively). Thus, the results obtained in this study prove that both ETM and BLM theories are appropriate to predict single and mixture REMs toxicity, providing coherent and promising tools for the risk assessment of REM pollution.

Phytotoxicity of individual and binary mixtures of rare earth elements (Y, La, and Ce) in relation to bioavailability.

Rare earth elements (REEs) are typically present as mixtures in the environment, but a quantitative understanding of mixture toxicity and interactions of REEs is still lacking. Here, we examined the toxicity to wheat (Triticum aestivum L.) of Y, La, and Ce when applied individually and in combination. Both concentration addition (CA) and independent action (IA) reference models were used for mixture toxicity analysis because the toxicity mechanisms of REEs remain obscure. Upon single exposure, the EC50s of Y, La, and Ce, expressed as dissolved concentrations, were 1.73 ±â€¯0.24 µM, 2.59 ±â€¯0.23 µM, and 1.50 ±â€¯0.22 µM, respectively. The toxicity measured with relative root elongation followed La < Y ≈ Ce, irrespective of the dose descriptors. The use of CA and IA provided similar estimates of REE mixture interactions and toxicity. When expressed as dissolved metal concentrations, nearly additive effects were observed in Y-La and La-Ce mixtures, while antagonistic interactions were seen in Y-Ce mixtures. When expressed as free metal activities, antagonistic interactions were found for all three binary mixtures. This can be explained by a competitive effect of REEs ions for binding to the active sites of plant roots. The application of a more elaborate MIXTOX model in conjunction with the free ion activities, which incorporates the non-additive interactions and bioavailability-modifying factors, well predicted the mixture toxicity (with >92% of toxicity variations explained). Our results highlighted the importance of considering mixture interactions and subsequent bioavailability in assessing the joint toxicity of REEs.

Complete mitochondrial genomes confirm the generic placement of the plateau vole, Neodon fuscus.

The plateau vole, Neodon fuscus is endemic to China and is distributed mainly in Qinghai Province. It is of public health interest, as it is, a potential reservoir of Toxoplasma gondii and the intermediate host of Echinococcus multilocularis However, genetic data of this species are lacking, and its name and taxonomy are still a controversy. In the present study, we determined the nucleotide sequence of the entire mitochondrial (mt) genome of N. fuscus and analyzed its evolutionary relationship. The mitogenome was 16328 bp in length and contained 13 protein-coding genes, 22 genes for transfer RNAs (tRNA), two ribosomal RNA genes and two major noncoding regions (OL region and D-loop region). Most genes were located on the heavy strand. All tRNA genes had typical cloverleaf structures except for tRNASer (GCU) The mt genome of N. fuscus was rich in A+T (58.45%). Maximum likelihood (ML) and Bayesian methods yielded phylogenetic trees from 33 mt genomes of Arvicolinae, in which N. fuscus formed a sister group with Neodon irene and Neodon sikimensis to the exclusion of species of Microtus and other members of the Arvicolinae. Further phylogenetic analyses (ML only) based on the cytb gene sequences also demonstrated that N. fuscus had a close relationship with N. irene The complete mitochondrial genome was successfully assembled and annotated, providing the necessary information for the phylogenetic analyses. Although the name Lasiopodomys fuscus was used in the book 'Wilson & Reeder's Mammal Species of the World', we have confirmed here that its appropriate name is N. fuscus through an analysis of the evolutionary relationships.