Skin proteomic screening and functional analysis of differential proteins associated with coat color in sheep (Ovis aries).

Objective: Coat color is an important characteristic and economic trait in domestic sheep. In this study, we explored the potential mechanisms and the signaling pathways involved in coat color regulation for sheep. Methods: Isobaric tags for relative and absolute quantification (iTRAQ) technology was used to catalog global protein expression profiles in skin of sheep with black versus white coat color. Immunofluorescence was used to observe the expression localization of differential protein. Western blot and quantitative real time polymerase chain reaction (qRT-PCR) were used to evaluate their role in the coat color formation of sheep. Results: A total of 136 differential proteins were obtained in different coat colors, including 101 up-regulated and 35 down-regulated. Pigmentation function entries were enriched through GO annotation. Tyrosine metabolism and platelet activation signaling pathway were extracted by KEGG analysis. APOA1 (Apolipoprotein A-1) and FGA (Fibrinogen alpha chain) were found to be critical differential proteins by the interaction of differential proteins in the direct-interaction network diagram. Strikingly, twenty candidate differential proteins were screened, from which ACTB (Beta-actin) protein showed higher expression in white sheep skin, while ALB (albumin), APOA1 MAOA (Amine oxidase) and FGA proteins showed higher expression in black sheep skin, which validated by immunofluorescence, western blot and qRT-PCR. Conclusion: Our studies identified several novel proteins that may involved in the coat color formation of sheep. The white and black sheep skin proteome profiles obtained provide a valuable resource for future research to understand the network of protein expression controlling skin physiology and melanogenesis in sheep.

Proteomic Analysis of the Mitochondrial Responses in P19 Embryonic Stem Cells Exposed to Florfenicol.

Florfenicol (FLO) has been shown to elicit diverse toxic effects in plants, insects, and mammals. Previously, our investigations revealed that FLO induced abnormal cardiac development and early embryonic mortality in chicken embryos. However, the effect of FLO on mitochondrial responses in stem cells remains unclear. In this study, we show that FLO significantly diminishes proliferation viability and obstructs the directed differentiation of P19 stem cells (P19SCs) into cardiomyocytes. Proteomic analysis revealed 148 differentially expressed proteins in response to FLO. Functional analysis has pinpointed FLO interference with biological processes associated with oxidative phosphorylation within the mitochondria. In alignment with the results of proteomic analysis, we confirmed that FLO inhibits the expression of both nuclear DNA-encoded and mitochondrial DNA-encoded subunits of the electron transport chain. Subsequent experiments demonstrated that FLO disrupts mitochondrial dynamics and induces the mitochondrial unfolded protein response to maintain mitochondrial homeostasis. These findings collectively highlight the significance of mitochondrial dynamics and the mitochondrial unfolded protein response to mediate the decreased proliferation viability and directed differentiation potential in P19SCs treated with FLO. In conclusion, this study provides a comprehensive overview of mitochondrial responses to FLO-induced cytotoxicity and enhances our understandings of the molecular mechanisms underlying FLO-induced embryonic toxicity.

Expression and tissue distribution analysis of vimentin and transthyretin proteins associated with coat colors in sheep (Ovis aries).

OBJECTIVE: Pigment production and distribution are controlled through multiple proteins, resulting in different coat color phenotypes of sheep. METHODS: The expression distribution of vimentin (VIM) and transthyretin (TTR) in white and black sheep skins was detected by liquid chromatography-electrospray ionization tandem MS (LC-ESI-MS/MS), gene ontology (GO) statistics, immunohistochemistry, Western blot, and quantitative real time polymerase chain reaction (qRT-PCR) to evaluate their role in the coat color formation of sheep. RESULTS: LC-ESI-MS/MS results showed VIM and TTR proteins in white and black skin tissues of sheep. Meanwhile, GO functional annotation analysis suggested that VIM and TTR proteins were mainly concentrated in cellular components and biological process, respectively. Further research confirmed that VIM and TTR proteins were expressed at significantly higher levels in black sheep skins than in white sheep skins by Western blot, respectively. Immunohistochemistry notably detected VIM and TTR in hair follicle, dermal papilla, and outer root sheath of white and black sheep skins. qRT-PCR results also revealed that the expression of VIM and TTR mRNAs was higher in black sheep skins than in white sheep skins. CONCLUSION: The expression of VIM and TTR were higher in black sheep skins than in white sheep skins and the transcription and translation were unanimous in this study. VIM and TTR proteins were expressed in hair follicles of white and black sheep skins. These results suggested that VIM and TTR were involved in the coat color formation of sheep.

Exposure to bisphenol A induces neurotoxicity associated with synaptic and cytoskeletal dysfunction in neuro-2a cells.

Bisphenol A (BPA) has been reported to injure the developing and adult brain. However, the underlying mechanism still remains elusive. This study used neuro-2a cells as a cellular model to investigate the neurotoxic effects of BPA. Microtubule-associated protein 2 (MAP2) and tau protein maintain microtubule normal function and promote the normal development of the nervous system. Synaptophysin (SYP) and drebrin (Dbn) proteins are involved in regulating synaptic plasticity. Cells were exposed to the minimum essential medium (MEM), 0.01% (v/v) DMSO, and 150 µM BPA for 12, 24, or 36 h. Morphological analysis revealed that the cells in the BPA-treated groups shrank and collapsed compared with those in the control groups. CCK-8 and lactate dehydrogenase assay (LDH) assays showed that the mortality of neuro-2a cells increased as the BPA treatment time was prolonged. Ultrastructural analysis further revealed that cells demonstrated nucleolar swelling, dissolution of nuclear and mitochondrial membranes, and partial mitochondrial condensation following exposure to BPA. BPA also decreased the relative protein expression levels of MAP2, tau, and Dbn. Interestingly, the relative protein expression levels of SYP increased. These results indicated that BPA inhibited the proliferation and disrupted cytoskeleton and synaptic integrity of neuro-2a cells.

Exposure to fluoride induces apoptosis in the liver, kidney, and heart of Xenopus laevis by regulating the Caspase-8/3 signaling pathway.

Fluoride compounds are abundant and widely distributed in the environment at various concentrations, which can seriously injure the human body. In this study, we aim to evaluate the effects of excessive fluoride exposure on the liver, kidney, and heart tissues of healthy female Xenopus laevis by administering NaF (0, 100, and 200 mg/L) in drinking water for 90 days. The expression level of procaspase-8, cleaved-caspase-8, and procaspase-3 proteins were determined by Western blot. Compared with the control group, the group exposed to NaF exhibited expression levels of procaspase-8, cleaved-caspase-8, and procaspase-3 proteins that were considerably upregulated at a concentration of 200 mg/L in the liver and kidney. The cleaved-caspase-8 protein expression in the group exposed to a high concentration of NaF was lower than that in the control group in heart. Histopathological results by hematoxylin and eosin staining showed that excessive NaF exposure caused necrosis of hepatocytes and vacuolization degeneration. Granular degeneration and necrosis in renal tubular epithelial cells were also observed. Moreover, hypertrophy of myocardial cells, atrophy of myocardial fibers and disorder of myocardial fibers were detected. These results demonstrated that NaF-induced apoptosis and the mediated death receptor pathway activation ultimately damaged the liver and kidney tissues. This finding offers a fresh perspective on the effects of F-induced apoptosis in X. laevis.

Fluoride exposure disrupts the cytoskeletal arrangement and ATP synthesis of HT-22 cell by activating the RhoA/ROCK signaling pathway.

BACKGROUND: Fluoride, an environmental contaminant, is ubiquitously present in air, water, and soil. It usually enters the body through drinking water and may cause structural and functional disorders in the central nervous system in humans and animals. Fluoride exposure affects cytoskeleton and neural function, but the mechanism is not clear. METHODS: The specific neurotoxic mechanism of fluoride was explored in HT-22 cells. Cellular proliferation and toxicity detection were investigated by CCK-8, CCK-F, and cytotoxicity detection kits. The development morphology of HT-22 cells was observed under a light microscope. Cell membrane permeability and neurotransmitter content were determined using lactate dehydrogenase (LDH) and glutamate content determination kits, respectively. The ultrastructural changes were detected by transmission electron microscopy, and actin homeostasis was observed by laser confocal microscopy. ATP enzyme and ATP activity were determined using the ATP content kit and ultramicro-total ATP enzyme content kit, respectively. The expression levels of GLUT1 and 3 were assessed by Western Blot assays and qRT-PCR. RESULTS: Our results showed that fluoride reduced the proliferation and survival rates of HT-22 cells. Cytomorphology showed that dendritic spines became shorter, cellular bodies became rounder, and adhesion decreased gradually after fluoride exposure. LDH results showed that fluoride exposure increased the membrane permeability of HT-22 cells. Transmission electron microscopy results showed that fluoride caused cells to swell, microvilli content decreased, cellular membrane integrity was damaged, chromatin was sparse, mitochondria ridge gap became wide, and microfilament and microtubule density decreased. Western Blot and qRT-PCR analyses showed that RhoA/ROCK/LIMK/Cofilin signaling pathway was activated by fluoride. F-actin/G-actin fluorescence intensity ratio remarkably increased in 0.125 and 0.5 mM NaF, and the mRNA expression of MAP2 was significantly decreased. Further studies showed that GLUT3 significantly increased in all fluoride groups, while GLUT1 decreased (p < 0.05). ATP contents remarkably increased, and ATP enzyme activity substantially decreased after NaF treatment with the control. CONCLUSION: Fluoride activates the RhoA/ROCK/LIMK/Cofilin signaling pathway, impairs the ultrastructure, and depresses the connection of synapses in HT-22 cells. Moreover, fluoride exposure affects the expression of glucose transporters (GLUT1 and 3) and ATP synthesis. Sum up fluoride exposure disrupts actin homeostasis, ultimately affecting structure, and function in HT-22 cells. These findings support our previous hypothesis and provide a new perspective on the neurotoxic mechanism of fluorosis.

Fine-Tuned Morphology Based on Two Well-Miscible Polymer Donors Enables Higher Open-Circuit Voltage and Enhanced Stability for Highly Efficient Ternary All-Polymer Solar Cells.

Developing organic solar cells based on a ternary active layer is one of the most effective approaches to improve their photovoltaic performance. However, limited success has been achieved in all-polymer solar cells (all-PSCs). In this study, a ternary all-PSC with improved efficiency and stability is realized by using J71 as the third component to adjust the host system of PBDB-T:PG1. The deeper highest occupied molecular orbital (HOMO) energy level of J71 downshifts the mixed HOMO energy levels of donors. The two polymer donors (PD s) have good miscibility and present Förster resonance energy transfer. When blended with PG1, the optimized morphology is obtained, showing enhanced crystallinity but meanwhile slightly reduced phase separation with improved exciton dissociation and collection efficiency, suppressed charge recombination, and reduced energy loss (0.55 eV). Combining the benefits mentioned above, the ternary all-PSC exhibits an excellent efficiency of 12.8% with simultaneously elevated open-circuit voltage (0.96 V), short-circuit current density (18.4 mA cm-2 ), and fill factor (72.2%). Moreover, the optimized ternary all-PSC shows improved storage and thermal stability. This study demonstrates that the utilization of a ternary all-polymer system based on two well-miscible PD s is an effective strategy to enhance the photovoltaic performance and stability of all-PSCs.

Performance evaluation of rhamnolipids addition for the biodegradation and bioutilization of petroleum pollutants during the composting of organic wastes with waste heavy oil.

Environmental pollution caused by petroleum hydrocarbons is being paid more and more attention worldwide. Surfactants are able to improve the solubility of petroleum hydrocarbons, but their effects on petroleum hydrocarbon degradation in composting systems are still unclear. In this study, the effects on microbial community succession were investigated by adding petroleum hydrocarbons and rhamnolipids during composting of organic wastes. The results showed that the compost and the addition of rhamnolipids could effectively reduce the petroleum hydrocarbon content with an efficiency of 73.52%, compared to 53.81% for the treatment without addition. Network analyses and Structural Equation Model suggested that there were multiple potential petroleum degraders microbes that might be regulated by nitrogen. The findings in this study can also provide an implication for the treatment of petroleum hydrocarbon pollutants from oil-polluted soil, and the technology can be potentially applied on an industrial scale in practice.

Response of fungi-microalgae pellets to copper regulation in the removal of sulfonamides and release of dissolved organic matters.

Both sulfonamides (SAs) and copper (Cu(II)) were frequently detected together in swine wastewater. In this study, the regulation of Cu(II) on SAs adsorption and release of dissolved organic matters (DOMs) by fungi-microalgae pellets (FM-pellets) were investigated. Aspergillus oryzae pellets were prepared for combination with Chlorella vulgaris and the optimal conditions were at agitation speed of 130 rpm, fungi to microalgae ratio of 10:1 and the combined time of 3 h with the highest combination efficiency of 98.65%. The results showed that adsorption was the main mechanism for SAs removal. FM-pellets exhibited a high SAs adsorption potential within 6 h, and the adsorption capacity of sulfamethazine (SMZ), sulfamonomethoxine (SMM) and sulfamethoxazole (SMX) was 1.07, 0.94 and 1.67 mg/g, respectively. Furthermore, the removal of SMX, SMZ and SMM was greatly promoted from 62.31% to 85.21%, 58.71-67.91% and 64.17-80.31%, respectively, under the presence of 2 mg/L Cu(II) through ion exchange and adsorption bridging. DOMs were analyzed by the parallel factor (PARAFAC) to demonstrate the response mechanism of FM-pellets to Cu(II). Protein-like substances and NADH in DOMs released by FM-pellets formed complexes with Cu(II) to alleviate the damage on the organism. These findings provide new insights into the mechanism and response of Cu(II) in the removal of SAs by FM-pellets.

Molecular Mechanisms Underlying the Inhibition of Proliferation and Differentiation by Florfenicol in P19 Stem Cells: Transcriptome Analysis.

Florfenicol (FLO), which is widely used in veterinary clinics and aquaculture, can disrupt the protein synthesis of bacteria and mitochondria and, thus, lead to antibacterial and toxic effects in plants, insects, and mammals. FLO was found to repress chicken embryonic development and induce early embryonic death previously, but the underlying mechanism is not fully understood. Clarifying the mechanism of FLO-induced embryonic toxicity is important to the research and development of new drugs and the rational use of FLO to ensure human and animal health and ecological safety. In this study, the effects of FLO on pluripotency, proliferation, and differentiation were investigated in P19 stem cells (P19SCs). We also identified differentially expressed genes and performed bioinformatics analysis to obtain hub genes and conducted some functional analysis. FLO inhibited the proliferation and pluripotency of P19SCs and repressed the formation of embryoid bodies derived from P19SCs. A total of 2,396 DEGs were identified using RNA-Seq in FLO-treated P19SCs, and these genes were significantly enriched in biological processes, such as angiogenesis, embryonic organ development, and morphogenesis of organs. Kyoto encyclopedia of genes and genome-based pathway analysis also showed that five relevant pathways, especially the canonical Wnt pathway, were engaged in FLO-induced toxicity of pluripotent stem cells. We further analyzed modules and hub genes and found the involvement of ubiquitin-mediated proteolysis, DNA replication, and cell cycle machinery in regulating the pluripotency and proliferation of FLO-treated P19SCs. In summary, our data suggest that FLO disrupts the signaling transduction of pathways, especially the canonical Wnt pathway, and further inhibits the expression of target genes involved in regulating DNA replication, cell cycle, and pluripotency. This phenomenon leads to the inhibition of proliferation and differentiation in FLO-treated P19SCs. However, further experiments are required to validate our findings and elucidate the potential mechanisms underlying FLO-induced embryonic toxicity.

Acute lead acetate induces neurotoxicity through decreased synaptic plasticity-related protein expression and disordered dendritic formation in nerve cells.

Lead (Pb) is a widespread environmental heavy metal that can damage the cerebral cortex and hippocampus, and reduce the learning and memory ability in humans and animals. In vivo and in vitro models of acute lead acetate exposure were established to further study the mechanism of neurons injury. In this study, 4-week-old female Kunming mice were randomly divided into four groups. Each group was treated with distilled water with different Pb concentrations (0, 2.4, 4.8 and 9.6 mM). Mice were killed, and brain tissues were collected to detect the changes in synaptic plasticity-related protein expression. Furthermore, Neuro-2A cells were treated with 0, 5, 25 and 50 µM lead acetate for 24 h to observe the changes in cell morphology and function. In in vivo experiment, results showed that the expression levels of cytoskeleton-associated and neural function-related proteins decreased in a dose-dependent manner in the mouse brain tissue. In in vitro experiment, compared with the control group, Pb treatment groups were observed with smaller and round cells, decreased cell density and number of synapses. In the Pb exposure group, the survival rate of nerve cells decreased evidently, and the permeability of the cell membrane was increased. Western blot results showed that the expression of cytoskeleton-associated and function-related proteins decreased gradually with increased Pb exposure dose. Confocal laser scanning microscopy results revealed the morphological and volumetric changes in Neuro-2A cells, and a dose-dependent reduction in the number of axon and dendrites. These results suggested that abnormal neural structures and inhibiting expression of synaptic plasticity-related proteins might be the possible mechanisms of Pb-induced mental retardation in human and animals, thereby laying a foundation for the molecular mechanism of Pb neurotoxicity.

Evaluation of BPA effects on autophagy in Neuro-2a cells.

Bisphenol A (BPA), which is used for the industrial production of polycarbonate plastics and epoxy resins, is found in many commercially available products. Plasticizer BPA produces chemical substances worldwide, and knowledge of its effects on humans and animals is increasing. In the present work, the morphology of cells was observed by optical microscopy and phalloidin staining to evaluate the toxic effect of BPA on Neuro-2a cells. Autophagy has an important role in the regulation of cell metabolism. To study the effect of BPA on the autophagy in Neuro-2a cells, the expression distribution of LC3 was detected by immunofluorescence, and the expression levels of p62 and Beclin1 were determined using western blot and quantitative real-time PCR (qRT-PCR), respectively. Optical microscopy and phalloidin staining revealed that the cells became rounded and small and that the dendritic spine of the cells were reduced at high BPA doses. Immunofluorescence analysis demonstrated that the expression of LC3 fluorescence intensity was weak at increasing BPA concentrations. Western blot results showed that the relative expression of protein p62 increased significantly and that the relative expression levels of the Beclin1 and the LC3 proteins significantly decreased with increasing BPA concentration. qRT-PCR results showed that the relative expression level of autophagy-related p62 mRNA increased significantly and that the relative expression level of Beclin1 mRNA decreased significantly with increasing BPA concentration. The above results indicated that BPA treatment exerted dose-dependent toxic effects on Neuro-2a cells, and BPA inhibited the autophagy level of Neuro-2a cells, thereby providing a new perspective in studying the toxic effect of BPA on Neuro-2a cells.

Bisphenol A induces apoptosis in response to DNA damage through c-Abl/YAPY357/ p73 pathway in P19 embryonal carcinoma stem cells.

Bisphenol A (2,2-bis(4'-hydroxyphenyl) propane, BPA) is a well-known endocrine-disrupting compound that is widely used in various daily products and exhibits embryonic development toxicity and genotoxicity. However, the affected signaling pathways involved in embryonic development especially the interactions of involved proteins remain unclear. In our previous study (Ge et al., 2021), BPA induces DNA damage and apoptosis in Xenopus embryos, resulting in multiple malformations of larvae. However, the signaling pathways induced for apoptosis response to DNA damage are still not well elucidated. Here, we systematically elucidated the enriched pathways affected by BPA and illustrated the interactions of involved proteins. Results indicated that BPA affected multiple embryonic development pathways including Hippo, TGF-ß, Wnt, and Notch pathways. Furthermore, the protein-protein interaction network suggested that the c-Abl/YAPY357/p73 pathway may play a key role in apoptosis induction in response to DNA damage. P19 embryonal carcinoma stem cells, as a developmental toxicity model, were treated with different BPA concentrations to establish an in vitro model to verify the role of the c-Abl/YAPY357/p73 pathway in apoptosis. BPA triggered DNA damage and significantly upregulated the expression levels of c-Abl, phosphorylated YAPY357, phosphorylated p73Y99, and cleaved caspase-3 protein (p < 0.05), thus decreasing cell viability and transcriptionally activating the p73 target genes Bax and Puma. These data suggested that BPA activated the c-Abl/YAPY357/p73 pathway in response to DNA damage. Imatinib, an inhibitor of tyrosine kinase c-Abl, significantly downregulated the elevated expression levels of p-YAPY357, p-p73Y99 and cleaved caspase-3 (p < 0.05) caused by BPA and then ameliorated the cell index of P19 cells in the BPA-treated group. Therefore, this substance restrained the phosphokinase activity of c-Abl and suppressed the c-Abl/YAPY357/p73 pathway. Results showed that the c-Abl/YAPY357/p73 pathway served as a mechanism for caspase-3 activation that induced the apoptosis response to DNA damage stress.

Recycling spent water from microalgae harvesting by fungal pellets to re-cultivate Chlorella vulgaris under different nutrient loads for biodiesel production.

Fungal pellet is an emerging material to collect oleaginous microalgae, but rare studies have noticed that harvested water is available resource for the next round of cultivation. To systematically optimize regrowth performances of microalgae Chlorella vulgaris, separated water after harvesting by fungi Aspergillus oryzae was prepared under different N/P ratios. The results showed that chlorophylls and enzymes were significantly affected by the proportion of N and P. Although nutrient deficiency was functioned as a stress factor to restrict carbohydrate and protein synthesis, lipid content was obviously increased by 12.69%. The percentage of saturated fatty acids associated with oxidation stability increased, while this part in fresh wastewater accounted for only 36.96%. The favorable biomass concentration (1.37 g/L) with the highest lipid yield (0.42 g/L) appeared in N/P of 6:1. More strikingly, suitable conditions could save 52.4% of cultivation costs. These experiments confirmed that reusing bioflocculated water could be effectively utilized for biodiesel production.

The complete mitogenome and phylogeny analysis of Pareuchiloglanis longicauda (Yue, 981) (Siluriformes: Sisoridae).

Pareuchiloglanis longicauda, a Sisorid fish that is distributed in the upper Pearl River. In this study, the complete mitogenome of P. longicauda was sequenced using traditional Sanger sequencing approach. The 16,588 bp genome was consisted of 2 rRNAs, 22tRNAs, 13 protein-coding genes (PCGs) and 1 control region. The 13 PCGs started with a traditional ATG and end with stop codon TAA, TAG, TGA, TA or a single T base. Phylogenetic analysis based on 13 PCGs from 22 species using maximum-likelihood method produced three major clades (Clade I, II and III). Unexpectedly, our mitogenome exhibited only 92.12% identity to the previously published one (GenBank accession no. KP872693) with differences mainly located in the gene region. Furthermore, Pareuchiloglanis did not form a monophyletic genus and P. longicauda had the closest relationship with P. macrotrema. The result suggested that more complete mitogenomes are needed to reveal the phylogenetic placement of Pareuchiloglanis in the family Sisoridae.

Evaluation of growth and biochemical responses of freshwater microalgae Chlorella vulgaris due to exposure and uptake of sulfonamides and copper.

Sulfonamides (SAs) and heavy metals are frequently detected together in livestock wastewater. In this study, evaluations regarding their potentially adverse effects on microalgae and according removals were investigated. Results showed that the growth of C. vulgaris was inhibited by SAs and Cu. There was an obvious recovery period in photosynthetic activity (Fv/Fm), indicating that the damage to the photosystem of microalgae was reversible. The co-existence of SAs and Cu significantly affected the biochemical characteristics, including the activities of antioxidant enzyme and the contents of photosynthetic pigments, proteins and polysaccharides. The addition of Cu obviously promoted the removal efficiencies of SMZ, SMX and SMM, which might be ascribed to the bridging effect of Cu in the bioadsorption of SAs. This study is conducive to understand the changes in the biochemical responses of microalgae under the combined impacts of SAs and Cu, and provides a new insight for the simultaneous removals.

Microalgae Chlorella vulgaris and Scenedesmus dimorphus co-cultivation with landfill leachate for pollutant removal and lipid production.

In this study, landfill leachate was pre-treated with NaClO, and then diluted to 5%, 10% and 15% for microalgae growth of Chlorella vulgaris and Scenedesmus dimorphus in the mono- and co-culture modes to investigate the nutrient removal and growth characteristics of microalgae. The results revealed that landfill leachate with the 10% dilution rate was conducive for microalgae growth and exhibited robust biomass growth and the highest nutrient removal efficiency. The co-culture biomass in 10% landfill leachate achieved 0.266 g/L within 10 days and demonstrated the improved nutrient utilisation efficiency of microalgae. In addition, the chemical oxygen demand, ammonia nitrogen, total nitrate and total phosphorus removal efficiencies accordingly reached 81.0%, 80.1%, 72.1% and 86.0% in 10% landfill leachate. Meanwhile, both the enzyme activity and fluorescence parameters proved that the cell activity of co-culture was higher than that of mono-culture.

Radical-Driven Decomposition of Graphitic Carbon Nitride Nanosheets: Light Exposure Matters.

Understanding the transformation of graphitic carbon nitride (g-C3N4) is essential to assess nanomaterial robustness and environmental risks. Using an integrated experimental and simulation approach, our work has demonstrated that the photoinduced hole (h+) on g-C3N4 nanosheets significantly enhances nanomaterial decomposition under •OH attack. Two g-C3N4 nanosheet samples D and M2 were synthesized, among which M2 had more pores, defects, and edges, and they were subjected to treatments with •OH alone and both •OH and h+. Both D and M2 were oxidized and released nitrate and soluble organic fragments, and M2 was more susceptible to oxidation. Particularly, h+ increased the nitrate release rate by 3.37-6.33 times even though the steady-state concentration of •OH was similar. Molecular simulations highlighted that •OH only attacked a limited number of edge-site heptazines on g-C3N4 nanosheets and resulted in peripheral etching and slow degradation, whereas h+ decreased the activation energy barrier of C-N bond breaking between heptazines, shifted the degradation pathway to bulk fragmentation, and thus led to much faster degradation. This discovery not only sheds light on the unique environmental transformation of emerging photoreactive nanomaterials but also provides guidelines for designing robust nanomaterials for engineering applications.

A fungal immobilization technique for efficient harvesting of oleaginous microalgae: Key parameter optimization, mechanism exploration and spent medium recycling.

To confront with energy crisis, microalgae as the promising feedstock have a great potential in exploring renewable energy field, whereas the high costs related to medium preparation and biomass harvesting are the main bottleneck to hinder the development on a large scale. Though cultivation of filamentous fungi for microalgae harvesting is an efficient, sustainable and emerging method, and the studies on specific mechanisms and spent medium recycling for efficiency improvement as well as resource saving through a co-pelletization mode are urgently needed. Hence, in this study, the harvesting process of autotrophic microalgae Chlorella vulgaris by pre-cultured Aspergillus oryzae pellets was investigated systematically. The highest efficiency (99.23%) was obtained within 5 h under the optimized conditions of 30 °C, 130 rpm and fungi:algae ratio of 1:1 on a dry weight basis without demand for pH adjustment (initial value on 9.68). Charge neutralization was not the main mechanisms involved in fungi-algae aggregations, and the functional group changes on cell surfaces as well as secreted metabolites in medium could be mainly responsible for inducing the bioflocculation process. After harvesting, separated water could also effectively support microalgae re-growth. The biomass concentration in medium with 50% recycling was higher than that in fresh medium, while lipid content was increased from 24.37% to 33.97% in fully recycled medium. These results indicated that the pellet-assisted mode for algal harvesting is a promising way to promote biofuel production and resource recycling.

13.4 % Efficiency from All-Small-Molecule Organic Solar Cells Based on a Crystalline Donor with Chlorine and Trialkylsilyl Substitutions.

How to simultaneously achieve both high open-circuit voltage (Voc ) and high short-circuit current density (Jsc ) is a big challenge for realising high power conversion efficiency (PCE) in all-small-molecule organic solar cells (all-SM OSCs). Herein, a novel small molecule (SM)-donor, namely FYSM-SiCl, with trialkylsilyl and chlorine substitutions was designed and synthesized. Compared to the original SM-donor FYSM-H, FYSM-Si with trialkylsilyl substitution showed a decreased crystallinity and lower highest occupied molecular orbital (HOMO) level, while FYSM-SiCl had an improved crystallinity, more ordered packing arrangement, significantly lower HOMO level, and predominant "face-on" orientation. Matched with a SM-acceptor Y6, the FYSM-SiCl-based all-SM OSCs exhibited both high Voc of 0.85 V and high Jsc of 23.7 mA cm-2 , which is rare for all-SM OSCs and could be attributed to the low HOMO level of FYSM-SiCl donor and the delicate balance between high crystallinity and suitable blend morphology. As a result, FYSM-SiCl achieved a high PCE of 13.4 % in all-SM OSCs, which was much higher than those of the FYSM-H- (10.9 %) and FYSM-Si-based devices (12.2 %). This work demonstrated a promising method for the design of efficient SM-donors by a side-chain engineering strategy via the introduction of trialkylsilyl and chlorine substitutions.