Effects of nanomaterials on metal toxicity: Case study of graphene family on Cd.

The risk of heavy metal cadmium (Cd) on aquatic organisms has drawn widespread attentions, but the effects of nanomaterials (e.g. graphene (G)) on Cd toxicity are rarely clarified. It was known that mixture of contaminants may exhibit more severe impact than the individual metal. Here, we conducted a study systematically on the effects of nanomaterials on the toxicity of Cd to Scenedesmus Obliquus (S. obliquus) with or without the presence of graphene family materials (GFMs) derived from G, such as graphene oxide (GO) and amine-modified graphene (GNH). Our results showed that the influence of GFMs on the acute toxicity of Cd to S. obliquus is in the order of GO > G > GNH based on their EC50 of Cd-GFMs. The effects of GFMs on the cytotoxicity and oxidative damage of Cd to S. obliquus are varied with the concentrations of GFMs. The differences between the effects of GFMs on Cd toxicity may attribute to their different surface oxygen-containing functional groups contained in the nanomaterials. The adsorption capacity of nanomaterials on metal ions, their dispersibility in water and their interaction mode with organisms, may dominate main contributions to their effects on Cd toxicity. Our study aids to clarify the interference of nanoparticles on the ecotoxicity of metals, to avoid the misunderstanding of the potential risk of metals in the complicate water environments.

An integrated multi-omics analysis reveals osteokines involved in global regulation.

Bone secretory proteins, termed osteokines, regulate bone metabolism and whole-body homeostasis. However, fundamental questions as to what the bona fide osteokines and their cellular sources are and how they are regulated remain unclear. In this study, we analyzed bone and extraskeletal tissues, osteoblast (OB) conditioned media, bone marrow supernatant (BMS), and serum, for basal osteokines and those responsive to aging and mechanical loading/unloading. We identified 375 candidate osteokines and their changes in response to aging and mechanical dynamics by integrating data from RNA-seq, scRNA-seq, and proteomic approaches. Furthermore, we analyzed their cellular sources in the bone and inter-organ communication facilitated by them (bone-brain, liver, and aorta). Notably, we discovered that senescent OBs secrete fatty-acid-binding protein 3 to propagate senescence toward vascular smooth muscle cells (VSMCs). Taken together, we identified previously unknown candidate osteokines and established a dynamic regulatory network among them, thus providing valuable resources to further investigate their systemic roles.

The adverse effect of biochar to aquatic algae- the role of free radicals.

The application of biochar in remediation and recovery of heavy metals and/or organic contaminants in water and soil is increasing. However, the adverse effect of biochar to aquatic organisms has not received enough attention. In this study, we conducted a study on the biotoxicity of biochar pyrolyzed from pine needle under oxygen-limited conditions. The toxicity of biochar was expressed with the following endpoints: cell growth, chlorophyll-a (Chl-a), reactive oxygen species (ROS), superoxide dismutase (SOD) content of Scenedesmus obliquus (S. obliquus) and the luminescence of Photobacterium phosphoreum (P. phosphoreum). Here, the effect of free radicals (FRs) contained in biochar was stressed. Our results show that the toxicity of biochar is significantly correlated with the concentration of FRs in biochar particles. Meanwhile, we found the FRs-containing biochar could induce the production of acellular ROS (such as ·OH) in water, which would also induce the production of interior cellular ROS in aquatic organisms. Our findings provide a new insight into the mechanism of toxicity aroused by biochar applications and aid in understanding its potential ecological risk.

Influence of humic substances on the toxic effects of cadmium and SDBS to the green alga Scenedesmus obliquus.

The joint toxicity of chemicals mixture in the aquatic environment was still not well clear. To clarify the joint toxicity of the mixtures of metals and organic pollutants, as well as the influence of dissolved organic matter (DOM) in field water-body on their toxic effects, we conducted the toxicity tests with cadmium (Cd) and sodium dodecyl benzene sulfonate (SDBS) on Scenedesmus obliquus (S. obliquus) with or without the presence of fulvic acid (FA), a typical of DOM. Our results showed Cd was more toxic to S. obliquus than SDBS, and the effects of fulvic acid on SDBS were greater than Cd. The joint toxicity of Cd and SDBS expressed a synergistic effect on S. obliquus, which was observed to be increased with the presence of FA. Our results gave an example for the joint toxicity investigations of organics and metals, aiding to understanding the toxicity of pollutant mixtures in field water bodies containing DOM.

The role of microtubule-associated protein 1B in axonal growth and neuronal migration in the central nervous system.

In this review, we discuss the role of microtubule-associated protein 1B (MAP1B) and its phosphorylation in axonal development and regeneration in the central nervous system. MAP1B exhibits similar functions during axonal development and regeneration. MAP1B and phosphorylated MAP1B in neurons and axons maintain a dynamic balance between cytoskeletal components, and regulate the stability and interaction of microtubules and actin to promote axonal growth, neural connectivity and regeneration in the central nervous system.

[Experiment of rhBMP-2 in posterolateral spinal fusion in aged rabbits].

OBJECTIVE: Posterolateral intertransverse process fusion was performed in aged and young adult female rabbits lumbar spine using recombinant human bone morphogenetic protein-2 (rhBMP-2) and autograft to reveal the function of rhBMP-2 on spinal fusion on aged animals. METHODS: A total of 24 female New Zealand white rabbits included 12 young adult of 6 months and 12 aged of 2-year-old, was divided into 4 groups: (1) young adult autologous iliac crest bone group [ICBG(Y), n=6); (2) young adult rhBMP-2/absorbable collagen sponge (ACS) group [BMP-2(Y), n=6]; (3) aged autologous iliac crest bone group [ICBG(O), n=6]; aged rhBMP-2/ACS group [BMP-2(O), n=6]. All were underwent posterolateral fusion in same day. rhBMP-2 and autologous iliac crest bone was implant bilateral LS-L6 intertransverse processes, respectively. Half of the rabbits were sacrificed at 3.6 weeks following surgery, respectively. The results were assessed by manual palpation, radiographs, computed tomographic scans (3D) and histology. RESULTS: Six weeks after surgery, radiography, computed tomography and histology indicated the different result in healing in the posterolateral fusion using rhBMP-2 compared to ICBG (P < 0.05). Aged BMP-2 group showed significantly higher fusion rates than Aged ICBG group. CONCLUSION: This study demonstrated rhBMP-2 can increase the posterolateral fusion rate and new bone quality in aged rabbitss than autograft, it may take the place of ICBG. But its role is effected by age.