Molecular Responses of Mouse Macrophages to Copper and Copper Oxide Nanoparticles Inferred from Proteomic Analyses

The molecular responses of macrophages to copper-based nanoparticles have been investigated via a combination of proteomic and biochemical approaches, using the RAW264.7 cell line as a model. Both metallic copper and copper oxide nanoparticles have been tested, with copper ion and zirconium oxide nanoparticles used as controls. Proteomic analysis highlighted changes in proteins implicated in oxidative stress responses (superoxide dismutases and peroxiredoxins), glutathione biosynthesis, the actomyosin cytoskeleton, and mitochondrial proteins (especially oxidative phosphorylation complex subunits). Validation studies employing functional analyses showed that the increases in glutathione biosynthesis and in mitochondrial complexes observed in the proteomic screen were critical to cell survival upon stress with copper-based nanoparticles; pharmacological inhibition of these two pathways enhanced cell vulnerability to copper-based nanoparticles, but not to copper ions. Furthermore, functional analyses using primary macrophages derived from bone marrow showed a decrease in reduced glutathione levels, a decrease in the mitochondrial transmembrane potential, and inhibition of phagocytosis and of lipopolysaccharide-induced nitric oxide production. However, only a fraction of these effects could be obtained with copper ions. In conclusion, this study showed that macrophage functions are significantly altered by copper-based nanoparticles. Also highlighted are the cellular pathways modulated by cells for survival and the exemplified cross-toxicities that can occur between copper-based nanoparticles and pharmacological agents.Manufactured nanoparticles are more and more widely used in more and more consumer products, ranging from personal care products to tires and concrete. Among the nanoparticles, metals and metal oxides represent an important part of the total production and are used in water treatment, as antibacterials, in antifouling paints, and in microelectronics. These varied uses in turn pose the problem of the toxicological evaluation of these nanoparticles (1, 2), and especially of the long-term effects that often come not from simple cell mortality but from altered cellular functions.Macrophages are one of the cell types that deserve special attention in toxicology, because of the variety of their functions. Altered cytokine production can lead to adverse long-term effects, as documented, for example, in the case of asbestos (3). Other dysfunctions of the innate immune system can lead to deregulation of the immune responses and to severe adverse effects, such as a higher incidence of tumors (4).It is therefore not surprising that the immunotoxicology of nanoparticles is a developing field (5–7), and several studies have been devoted to macrophages'' response to nanoparticles. However, most of these studies have been limited to the effect of nanoparticles on cell viability and on cytokine production (e.g. 8–11), although some also studied oxidative stress (12–14) and sometimes other functional parameters (15–17). Very few studies have used the analytical power of proteomics to go deeper into the mechanisms of the response to nanoparticles or metals (reviewed in Ref. 18). A few exceptions are studies on, for example, carbon-based nanoparticles (19) and titanium dioxide (20, 21).Most of the toxicological studies in this field have been focused on a few nanoparticles used either as health products, such as iron oxide (15, 17, 22), or in a variety of consumer products, such as silver (13, 14), silica (9, 12), and titanium dioxide (11, 16, 20, 21).However, many other nanoparticles are being used more and more in industrial applications without extensive toxicological testing. Good examples are indium-tin oxide, used in electronic screens, which appears to be toxic (23), and the copper-based nanoparticles used in high-performance batteries (24), in water depollution (25), and as bactericides as a replacement for nano-silver. Copper and copper oxide induce a strong toxicity (26, 27), coupled with inflammation (28), oxidative stress (29), and genotoxicity (30), at least in epithelial cells.In light of these various effects, we decided to use a combination of a proteomics approach and targeted approaches to address in more molecular detail the responses of macrophages to copper-based nanoparticles (i.e. both metallic copper and copper II oxide).     

我国巢鼠属分类和分子系统学分析

本研究对2018至2021年采集的9号巢鼠(Micromys minutus)标本、22号红耳巢鼠(M. erythrotis)标本和19号待厘定的巢鼠属标本,进行形态分类和分子系统学分析,进一步揭示我国巢鼠属的分类和系统分化问题。待厘定的巢鼠属标本形态特征为：标本体背毛黑棕,体腹毛基灰色,毛尖灰白,体侧毛色具明显区分,尾背部毛色黑棕,尾腹部毛色灰棕色;尾长长于头体长的120%;头骨背面观可见颧弓明显弯曲;颅全长[(18.59 ± 0.48)mm]和颅基长[(17.43 ± 0.48 mm)]较长,腭长[(9.35 ± 0.11)mm]较长,脑颅高[(7.43 ± 0.06)mm]较高。待厘定的巢鼠属标本形态特征与巢鼠和红耳巢鼠均存在差异。待厘定巢鼠属标本与巢鼠和红耳巢鼠之间的遗传距离分别为0.115和0.136,接近于巢鼠与红耳巢鼠之间的遗传距离(0.126)。利用Cyt b基因全序列和核基因IRBP1、RAG1和RAG2序列分别构建的巢鼠属系统发生树均以较高的置信度分化成3个进化支,即巢鼠、红耳巢鼠和待厘定的巢鼠属样本的进化支。形态学和分子系统学分析结果均支持待厘定的巢鼠属标本为独立物种分类单元,对应于文献记载的巢鼠川西亚种(M. m. pygmaeus)。根据产地、遗传距离和形态分化,建议将巢鼠川西亚种提升为种,命名为川西巢鼠(M. pygmaeus comb. nov.)。利用Cyt b基因全序列构建的巢鼠系统发生树分化成6个进化谱系：日韩谱系、欧洲谱系、俄罗斯新西伯利亚谱系、中国东北和俄罗斯远东谱系、中国安徽谱系和中国台湾谱系。     

Correction to: Genes Encoding Cucumber Full-Size ABCG Proteins Show Different Responses to Plant Growth Regulators and Sclareolide

Plant Molecular Biology Reporter - A Correction to this paper has been published: https://doi.org/10.1007/s11105-020-01265-4     

Cytogenetic and Molecular Analyses Reveal a Divergence between Acromyrmex striatus (Roger, 1863) and Other Congeneric Species: Taxonomic Implications

The leafcutter ants, which consist of Acromyrmex and Atta genera, are restricted to the New World and they are considered the main herbivores in the neotropics. Cytogenetic studies of leafcutter ants are available for five species of Atta and 14 species of Acromyrmex, both including subspecies. These two ant genera have a constant karyotype with a diploid number of 22 and 38 chromosomes, respectively. The most distinct Acromyrmex species from Brazil is A. striatus, which is restricted to the southern states of Santa Catarina and Rio Grande do Sul. Several cytogenetic and phylogenetic studies have been conducted with ants, but the karyotypic characterization and phylogenetic position of this species relative to leafcutter ants remains unknown. In this study, we report a diploid number of 22 chromosomes for A. striatus. The phylogenetic relationship between A. striatus and other leafcutter ants was estimated based on the four nuclear genes. A. striatus shared the same chromosome number as Atta species and the majority of metacentric chromosomes. Nuclear data generated a phylogenetic tree with a well-supported cluster, where A. striatus formed a different clade from other Acromyrmex spp. This combination of cytogenetic and molecular approaches provided interesting insights into the phylogenetic position of A. striatus among the leafcutter ants and the tribe Attini.     

Structural and Functional Analyses Reveal Insights into the Molecular Properties of the Escherichia coli Z Ring Stabilizing Protein,ZapC

In Escherichia coli cell division is driven by the tubulin-like GTPase, FtsZ, which forms the cytokinetic Z-ring. The Z-ring serves as a dynamic platform for the assembly of the multiprotein divisome, which catalyzes membrane cleavage to create equal daughter cells. Several proteins effect FtsZ assembly, thereby providing spatiotemporal control over cell division. One important class of FtsZ interacting/regulatory proteins is the Z-ring-associated proteins, Zaps, which typically modulate Z-ring formation by increasing lateral interactions between FtsZ protofilaments. Strikingly, these Zap proteins show no discernable sequence similarity, suggesting that they likely harbor distinct structures and mechanisms. The 19.8-kDa ZapC in particular shows no homology to any known protein. To gain insight into ZapC function, we determined its structure to 2.15 Å and performed genetic and biochemical studies. ZapC is a monomer composed of two domains, an N-terminal α/β region and a C-terminal twisted β barrel-like domain. The structure contains two pockets, one on each domain. The N-domain pocket is lined with residues previously implicated to be important for ZapC function as an FtsZ bundler. The adjacent C-domain pocket contains a hydrophobic center surrounded by conserved basic residues. Mutagenesis analyses indicate that this pocket is critical for FtsZ binding. An extensive FtsZ binding surface is consistent with the fact that, unlike many FtsZ regulators, ZapC binds the large FtsZ globular core rather than C-terminal tail, and the presence of two adjacent pockets suggests possible mechanisms for ZapC-mediated FtsZ bundling.     

Morphological and Genetic Analyses of Hellebore Leaf Spot Disease Isolates from Different Geographic Origins Show Low Variability and Reveal Molecular Evidence for Reclassification into Didymellaceae

Hellebore leaf spot, caused by Coniothyrium hellebori, is the most common fungal disease of Helleborus species not only in botanical and ornamental gardens but also in nurseries. To correct the current lack of knowledge regarding this widely distributed pathogen, this study investigated 25 C. hellebori isolates collected from different countries in North America and Europe, primarily Germany. The morphology, pathogenicity and molecular genetic relationships on the basis of random amplified polymorphic DNA (RAPD) of these isolates were studied. RAPD primers produced a total of 394 bands, of which 40% were polymorphic. Genetic distances were calculated, and a dendrogram with bootstrap analysis was constructed by the unweighted pair group method with arithmetic mean (UPGMA) cluster method. All isolates were identified as C. hellebori, the causal agent of the disease. Two C. hellebori subclades were found, which could not be correlated with the geographic origin of the isolate, but with the plant host species and morphological characteristics. Sequence comparisons of the large subunit and internal transcribed spacer loci between C. hellebori and sequences from GenBank revealed that C. hellebori has to be grouped into the Didymellaceae family and rather belongs to Phoma or Microsphaeropsis than to Coniothyrium. This work represents the first study of this plant pathogen causing severe damage in Helleborus stocks and provides important information for the development of future Helleborus resistance breeding strategies.