Cortical lipid metabolic pathway alteration of early Alzheimer's disease and candidate drugs screen.

BACKGROUND: Lipid metabolism changes occur in early Alzheimer's disease (AD) patients. Yet little is known about metabolic gene changes in early AD cortex. METHODS: The lipid metabolic genes selected from two datasets (GSE39420 and GSE118553) were analyzed with enrichment analysis. Protein-protein interaction network construction and correlation analyses were used to screen core genes. Literature analysis and molecular docking were applied to explore potential therapeutic drugs. RESULTS: 60 lipid metabolic genes differentially expressed in early AD patients' cortex were screened. Bioinformatics analyses revealed that up-regulated genes were mainly focused on mitochondrial fatty acid oxidation and mediating the activation of long-chain fatty acids, phosphoproteins, and cholesterol metabolism. Down-regulated genes were mainly focused on lipid transport, carboxylic acid metabolic process, and neuron apoptotic process. Literature reviews and molecular docking results indicated that ACSL1, ACSBG2, ACAA2, FABP3, ALDH5A1, and FFAR4 were core targets for lipid metabolism disorder and had a high binding affinity with compounds including adenosine phosphate, oxidized Photinus luciferin, BMS-488043, and candidate therapeutic drugs especially bisphenol A, benzo(a)pyrene, ethinyl estradiol. CONCLUSIONS: AD cortical lipid metabolism disorder was associated with the dysregulation of the PPAR signaling pathway, glycerophospholipid metabolism, adipocytokine signaling pathway, fatty acid biosynthesis, fatty acid degradation, ferroptosis, biosynthesis of unsaturated fatty acids, and fatty acid elongation. Candidate drugs including bisphenol A, benzo(a)pyrene, ethinyl estradiol, and active compounds including adenosine phosphate, oxidized Photinus luciferin, and BMS-488043 have potential therapeutic effects on cortical lipid metabolism disorder of early AD.

Ethical perspective on AI hazards to humans: A review.

This article explores the potential ethical hazards of artificial intelligence (AI) on society from an ethical perspective. We introduce the development and application of AI, emphasizing its potential benefits and possible negative impacts. We particularly examine the application of AI in the medical field and related ethical and legal issues, and analyze potential hazards that may exist in other areas of application, such as autonomous driving, finance, and security. Finally, we offer recommendations to help policymakers, technology companies, and society as a whole address the potential hazards of AI. These recommendations include strengthening regulation and supervision of AI, increasing public understanding and awareness of AI, and actively exploring how to use the advantages of AI to achieve a more just, equal, and sustainable social development. Only by actively exploring the advantages of AI while avoiding its negative impacts can we better respond to future challenges.

SET-mediated epigenetic dysregulation of p53 impairs trichloroethylene-induced DNA damage response.

Trichloroethylene (TCE) was a widely used industrial solvent, and now has become a major environmental pollutant. Exposure to TCE has been found to result in significant damage to the liver, leading to hepatic toxicity. In our previous study, we discovered that a histone chaperon called SET plays a crucial role in mediating the DNA damage and apoptosis caused by TCE in hepatic cells. However, the precise function of SET in the response to DNA damage is still not fully understood. In this study, we evaluated TCE-induced DNA damage of hepatic L-02 cells with SET-knockdown, then analyzed alterations of H3K79me3 and p53 in hepatic cells and carcinogenic mice livers. Results suggested that SET interferes with DNA response via mediating down-regulation of p53 and partially suppressing H3K79me3 under treatment of TCE. To further verify the regulatory cascade, H3K79me3 was reduced and p53 was knocked down in L-02 cells respectively, and extent of DNA damage was evaluated. Reduced H3K79me3 was found leading to down-regulation of p53 which further exacerbated TCE-induced DNA injury. These findings demonstrated that SET-H3K79me3-p53 served as an epigenetic regulatory axis involved in TCE-induced DNA damage response.

Salidroside alleviates cognitive impairment by inhibiting ferroptosis via activation of the Nrf2/GPX4 axis in SAMP8 mice.

BACKGROUND: Alzheimer's disease (AD) is a neurogenerative disease and remains no effective method for stopping its progress. Ferroptosis and adaptive immunity have been proven to contribute to AD pathogenesis. Salidroside exhibits neuroprotective and immunomodulatory effects. However, the underlying mechanisms linking salidroside, ferroptosis, and adaptive immunity in AD remain uncertain. PURPOSE: The objective of this study is to explore the neuroprotective effects and the potential molecular mechanisms of salidroside against neuronal ferroptosis and CD8+ T cell infiltration in senescence-accelerated mouse prone 8 (SAMP8) mice. STUDY DESIGN AND METHODS: SAMP8 mice were employed as an AD model and were treated with salidroside for 12 weeks. Behavioral tests, immunohistochemistry, HE and Nissl staining, immunofluorescence, transmission electron microscopy, quantitative proteomics, bioinformatic analysis, flow cytometry, iron staining, western blotting, and molecular docking were performed. RESULTS: Treatment with salidroside dose-dependently attenuated cognitive impairment, reduced the accumulation of Aß plaques and restored neuronal damage. Salidroside also suppressed the infiltration of CD8+T cells, oxidative stress, and inflammatory cytokines, and improved mitochondrial metabolism, iron metabolism, lipid metabolism, and redox in the SAMP8 mice brain. The administration of salidroside decreased iron deposition, reduced TFR1, and ACSL4 protein expression, upregulated SLC7A11, and GPX4 protein expression, and promoted the Nrf2/GPX4 axis activation. CONCLUSION: In conclusion, neuronal ferroptosis and CD8+T cells are involved in the process of cognitive impairment in SAMP8 mice. Salidroside alleviates cognitive impairment and inhibits neuronal ferroptosis. The underlying mechanisms may involve the Nrf2/GPX4 axis activation and reduction in CD8+T cells infiltration. This study provides some evidence for the roles of salidroside in adaptive immunity and neuronal ferroptosis in SAMP8 mice.

Akkermansia muciniphila ameliorates chronic kidney disease interstitial fibrosis via the gut-renal axis.

CONTEXT: Chronic kidney disease (CKD) affects approximately 10% of the global population. The abundance of Akkermansia muciniphila (AKK) is significantly reduced in CKD patients. OBJECTIVE: This study investigated the effects of AKK bacteria on kidney damage and the renal interstitium in rats with CKD. MATERIALS AND METHODS: CKD model 5/6 nephrectomy rats were used. CKD rats were supplemented with AKK (2 × 108 cfu/0.2 mL) for 8 weeks. RESULTS: AKK administration significantly suppressed epithelial-mesenchymal transition (EMT), and high-throughput 16S rRNA pyrosequencing showed that AKK supplementation restored the disordered intestinal microecology in CKD rats. AKK also enhanced the intestinal mucosal barrier function. AKK may regulate the intestinal microecology and reduce renal interstitial fibrosis by enhancing the abundance of probiotics and reducing damage to the intestinal mucosal barrier. CONCLUSION: The results suggest that AKK administration could be a novel therapeutic strategy for treating renal fibrosis and CKD.

Bacteroides plebeius improves muscle wasting in chronic kidney disease by modulating the gut-renal muscle axis.

Chronic kidney disease (CKD) affects approximately 10% of the global population. Muscle atrophy occurs in patients with almost all types of CKD, and the gut microbiome is closely related to protein consumption during chronic renal failure (CRF). This study investigated the effects of Bacteroides plebeius on protein energy consumption in rats with CKD, and our results suggest that Bacteroides plebeius may combat muscle atrophy through the Mystn/ActRIIB/SMAD2 pathway. A total of 5/6 Nx rats were used as a model of muscle wasting in CKD. The rats with muscle wasting were administered Bacteroides plebeius (2 × 108 cfu/0.2 ml) for 8 weeks. The results showed that Bacteroides plebeius administration significantly inhibited muscle wasting in CKD. High-throughput 16 S rRNA pyrosequencing revealed that supplementation with Bacteroides plebeius rescued disturbances in the gut microbiota. Bacteroides plebeius could also enhance the barrier function of the intestinal mucosa. Bacteroides plebeius may modulate the gut microbiome and reduce protein consumption by increasing the abundance of probiotics and reducing damage to the intestinal mucosal barrier. Our findings suggest that Bacteroides plebeius may combat muscle atrophy through the Mystn/ActRIIB/SMAD2 pathway.

Salidroside Alleviates Renal Fibrosis in SAMP8 Mice by Inhibiting Ferroptosis.

Renal fibrosis progression is closely associated with aging, which ultimately leads to renal dysfunction. Salidroside (SAL) is considered to have broad anti-aging effects. However, the roles and mechanisms of SAL in aging-related renal fibrosis remain unclear. The study aimed to evaluate the protective effects and mechanisms of SAL in SAMP8 mice. SAMP8 mice were administered with SAL and Ferrostatin-1 (Fer-1) for 12 weeks. Renal function, renal fibrosis, and ferroptosis in renal tissue were detected. The results showed that elevated blood urea nitrogen (BUN) and serum creatinine (SCr) levels significantly decreased, serum albumin (ALB) levels increased, and mesangial hyperplasia significantly reduced in the SAL group. SAL significantly reduced transforming growth factor-ß (TGF-ß) and α-smooth muscle actin (α-sma) levels in SAMP8 mice. SAL treatment significantly decreased lipid peroxidation in the kidneys, and regulated iron transport-related proteins and ferroptosis-related proteins. These results suggested that SAL delays renal aging and inhibits aging-related glomerular fibrosis by inhibiting ferroptosis in SAMP8 mice.

The Combination of Salidroside and Hedysari Radix Polysaccharide Inhibits Mitochondrial Damage and Apoptosis via the PKC/ERK Pathway.

Background: Beta-amyloid (Aß) peptide is a widely recognized pathological marker of Alzheimer's disease (AD). Salidroside and Hedysari Radix polysaccharide (HRP) were extracted from Chinese herb medicine Rhodiola rosea L and Hedysarum polybotrys Hand-Mazz, respectively. The neuroprotective effects and mechanisms of the combination of salidroside and Hedysari Radix polysaccharide (CSH) against Aß 25-35 induced neurotoxicity remain unclear. Objective: This study aims to investigate the neuroprotective effects and pharmacological mechanisms of CSH on Aß 25-35-induced HT22 cells. Materials and Methods: HT22 cells were pretreated with various concentrations of salidroside or HRP for 24 h, followed by exposed to 20 µm Aß 25-35 in the presence of salidroside or RHP for another 24 h. In a CSH protective assay, HT22 cells were pretreated with 40 µm salidroside and 20 µg/mL HRP for 24 h. The cell viability assay, cell morphology observation, determination of mitochondrial membrane potential (MMP), reactive oxygen species (ROS), and cell apoptosis rate were performed. The mRNA expression of protein kinase C-beta (PKCß), Bax, and Bcl-2 were measured by qRT-PCR. The protein expression levels of cleaved caspase-3, Cyt-C, PKCß, phospho-ERK1/2, Bax, and Bcl-2 were measured by Western blot. Results: CSH treatment increased cell viability, MMP, and decreased ROS generation in Aß 25-35-induced HT22 cells. PKCß and Bcl-2 mRNA expression were elevated by CSH while Bax was decreased. CSH increased the protein expression levels of PKCß, Bcl-2, and phospho-ERK1/2, and decreased those of Bax, Cyt-C, and cleaved caspase-3. Conclusions: CSH treatment have protective effects against Aß 25-35-induced cytotoxicity through decreasing ROS levels, increasing MMP, inhibiting early apoptosis, and regulating PKC/ERK pathway in HT22 cells. CSH may be a potential therapeutic agent for treating or preventing neurodegenerative diseases.

Salidroside attenuates neuronal ferroptosis by activating the Nrf2/HO1 signaling pathway in Aß1-42-induced Alzheimer's disease mice and glutamate-injured HT22 cells.

BACKGROUND: Alzheimer's disease (AD) is a neurodegenerative disease. Ferroptosis plays a critical role in neurodegenerative diseases. Nuclear factor E2-related factor 2 (Nrf2) is considered an important factor in ferroptosis. Studies have demonstrated that salidroside has a potential therapeutic effect on AD. The intrinsic effect of salidroside on ferroptosis is unclear. The purpose of this study was to investigate the protective effects and pharmacological mechanisms of salidroside on alleviating neuronal ferroptosis in Aß1-42-induced AD mice and glutamate-injured HT22 cells. METHODS: HT22 cells were injured by glutamate (Glu), HT22 cells transfected with siRNA Nrf2, and Aß1-42-induced WT and Nrf2-/-AD mice were treated with salidroside. The mitochondria ultrastructure, intracellular Fe2+, reactive oxygen species, mitochondrial membrane potential, and lipid peroxidation of HT22 cells were detected. Malondialdehyde, reduced glutathione, oxidized glutathione disulfide, and superoxide dismutase were measured. The novel object recognition test, Y-maze, and open field test were used to investigate the protective effects of salidroside on Aß1-42-induced WT and Nrf2-/-AD mice. The protein expressions of PTGS2, GPX4, Nrf2, and HO1 in the hippocampus were investigated by Western blot. RESULTS: Salidroside increased the cell viability and the level of MMP of Glu-injured HT22 cells, reduced the level of lipid peroxidation and ROS, and increased GPX4 and SLC7A11 protein expressions. These changes were not observed in siRNA Nrf2 transfected HT22 cells. Salidroside improved the ultrastructural changes in mitochondria of HT22 cells and Aß1-42-induced AD mice, but not in Aß1-42-induced Nrf2-/-AD mice. Salidroside increased protein expression levels of GPX4, HO1, and NQO1 and decreased protein expression of PTGS2 in Aß1-42-induced AD mice but not in Aß1-42-induced Nrf2-/-AD mice. CONCLUSIONS: Salidroside plays a neuroprotective role by inhibiting neuronal ferroptosis in Aß1-42-induced AD mice and Glu-injured HT22 cells, and its mechanism is related to activation of the Nrf2/HO1 signaling pathway.

[The relationship between methane production metabolic flux and microorganisms in a microbial electrolytic cell coupled anaerobic digestion].

In this study, voltage was used as a disturbance factor to investigate the relationship between microbial community and methane (CH4) production flux in a microbial electrolytic cell coupled anaerobic digestion (MEC-AD). Metabolic flux analysis (MFA) was used to explore the relationship between the CH4 metabolic flux produced and the microbes. The results showed that both methane production flux and hydrogen production flux changed significantly upon voltage disturbance, while the voltage disturbance had little effect on acetic acid production flux. The maximum CH4 production flux under 0.6 V disturbance was 0.522±0.051, which increased by 77% and 32%, respectively, compared with that of the control group under 1.0 V (0.295±0.013) and under 1.4 V (0.395±0.029). In addition, an average of 15.7%±2.9% of H2 (flux) was used to reduce CO2 to produce CH4 and acetic acid, and an average of 27.7%±6.9% of acetic acid (flux) was converted to CH4. Moreover, the abundance of Lachnospiraceae significantly affected the flux of acetic acid. The flux of CH4 production is positively correlated with the abundances of Petrimonas, Syntrophomonas, Blvii28, and Acinetobacter, and negatively correlated with the abundances of Tuzzerella and Sphaerochaeta. The species that affected the flux of H2 and CH4 were similar, mostly belonging to Bacteroides, Clostridium, Pseudomonas and Firmicutes. Furthermore, the interspecies interaction is also an important factor affecting the MEC-AD methanogenesis flux.

Introducing electrolysis to enhance anaerobic digestion resistance to acidification.

The phenomenon that the anaerobic system is inhibited by acid has always been a bottleneck hindering the application of anaerobic digestion (AD) technology. We tried to introduce electrolysis into AD to improve the acidification resistance, and eventually the productivity of the energy. In a batch fermentation device, the ability of electrochemical anaerobic digestion (EAD) to resist acidification was evaluated in current intensity, electrode potential, AC impedance, microbial community, pH value, and volatile fatty acids (VFAs). The results showed that the average concentration of VFAs in EAD was 32.9% lower than that in AD, the energy efficiency of EAD is 53.25% higher than AD, indicating that EAD has stronger anti-acidification ability and energy conversion efficiency than AD. When the EAD reaches a steady state, the current intensity fluctuates in the range of 7-12 mA, the electrode potential difference is maintained at 600 ± 5 mV, and the internal resistance decreases from 3333.3 ± 16Ω at startup to 68.9 ± 1.4Ω at the steady state, indicating that the EAD has stronger resistance to acidification may be due to the degradation of some VFAs on the electrode surface. Furthermore, the 16S rRNA sequencing analysis showed that the dominant electricity-producing bacteria on EAD anode surface were Clostridium, Hydrogenophaga and Trichloromonas, with a relative abundance of 40.32%, while the relative abundance of electrogenic bacteria in AD bulk solution and EAD bulk solution were about 1/2 and 1/4 that of EAD anode film, suggesting that the electricity-producing bacteria on the electrode surface play an important role in the degradation of VFAs.

Salidroside Attenuates Cognitive Dysfunction in Senescence-Accelerated Mouse Prone 8 (SAMP8) Mice and Modulates Inflammation of the Gut-Brain Axis.

Background: Alzheimer's disease (AD) is a fatal neurodegenerative disease characterized by progressive cognitive decline and memory loss. However, several therapeutic approaches have shown unsatisfactory outcomes in the clinical setting. Thus, developing alternative therapies for the prevention and treatment of AD is critical. Salidroside (SAL) is critical, an herb-derived phenylpropanoid glycoside compound, has been shown to attenuate lipopolysaccharide (LPS)-induced cognitive impairment. However, the mechanism underlying its neuroprotective effects remains unclear. Here, we show that SAL has a therapeutic effect in the senescence-accelerated mouse prone 8 (SAMP8) strain, a reliable and stable mouse model of AD. Methods: SAMP8 mice were treated with SAL, donepezil (DNP) or saline, and cognitive behavioral impairments were assessed using the Morris water maze (MWM), Y maze, and open field test (OFT). Fecal samples were collected and analyzed by 16S rRNA sequencing on an Illumina MiSeq system. Brain samples were analyzed to detect beta-amyloid (Aß) 1-42 (Aß1-42) deposition by immunohistochemistry (IHC) and western blotting. The activation of microglia and neuroinflammatory cytokines was detected by immunofluorescence (IF), western blotting and qPCR. Serum was analyzed by a Mouse High Sensitivity T Cell Magnetic Bead Panel on a Luminex-MAGPIX multiplex immunoassay system. Results: Our results suggest that SAL effectively alleviated hippocampus-dependent memory impairment in the SAMP8 mice. SAL significantly 1) reduced toxic Aß1-42 deposition; 2) reduced microglial activation and attenuated the levels of the proinflammatory factors IL-1ß, IL-6, and TNF-α in the brain; 3) improved the gut barrier integrity and modified the gut microbiota (reversed the ratio of Bacteroidetes to Firmicutes and eliminated Clostridiales and Streptococcaceae, which may be associated with cognitive deficits); and 4) decreased the levels of proinflammatory cytokines, particularly IL-1α, IL-6, IL-17A and IL-12, in the peripheral circulation, as determined by a multiplex immunoassay. Conclusion: In summary, SAL reversed AD-related changes in SAMP8 mice, potentially by regulating the microbiota-gut-brain axis and modulating inflammation in both the peripheral circulation and central nervous system. Our results strongly suggest that SAL has a preventive effect on cognition-related changes in SAMP8 mice and highlight its value as a potential agent for drug development.

Effects of different substrates on microbial electrolysis cell (MEC) anodic membrane: biodiversity and hydrogen production performance.

To investigate the effects of different substrates on the biodiversity and hydrogen production performance of microbial electrolysis cell (MEC) anodic membranes, the vital electroactive microorganisms (e.g. in MEC hydrogen production) were worth identifying. In the present study, single-factor experiments were performed. Sodium acetate, sodium propionate, sodium butyrate, glucose and starch served as different substrates for MEC anodic culture experiments under the same condition. The effects of different substrates on the bioactivity, biomass and hydrogen production performance of MEC anodic films were analyzed. Also, the effects of different microbial communities on hydrogen production were studied using 16S rRNA sequencing. According to the experimental results, all the five substrates here can serve as hydrogen-producing raw materials for MEC. All indicators revealed that sodium acetate, sodium propionate and sodium butyrate are excellent biofilm culture materials. The serious acidification of glucose and starch was identified at the same substrate concentration, and the environment of the culture medium was difficult to control, which affected the growth and metabolism of electroactive microorganisms. In comparison, sodium acetate was the best, achieving a maximum output of 23.4 mA and a maximum hydrogen content of 25.85%. The other four were ranked as sodium butyrate > sodium propionate > glucose > starch. According to the results of high-throughput sequencing, when sodium acetate, sodium propionate, sodium butyrate, glucose and starch served as substrates, the number of operational taxonomic units reached 464, 728, 636, 784, and 1,083, respectively. Furthermore, when MEC was cultured with sodium acetate, sodium propionate and sodium butyrate as substrates, the electroactive microorganism Desulfuromonas in the Proteobacteria would contribute the most to producing hydrogen. The relative abundance of the five substrates was ranked as sodium acetate > sodium butyrate > sodium propionate > glucose > starch, suggesting that the MEC anodic film cultured with sodium acetate as the substrate exhibited the best hydrogen production performance, and the starch showed the worst. It is noteworthy that Desulfuromonas was the most abundant species according to sequencing results. When glucose and starch served as substrates, they exhibited high biodiversity. The anodic membranes cultured with sodium acetate, sodium propionate and sodium butyrate were not as good as those cultured with glucose and starch, yet the electroactive microorganisms were up-regulated.

Divergent methylation pattern in adult stage between two forms of Tetranychus urticae (Acari: Tetranychidae).

The two-spotted spider mite, Tetranychus urticae Koch has two forms: green form and red form. Understanding the molecular basis of how these two forms established without divergent genetic background is an intriguing area. As a well-known epigenetic process, DNA methylation has particularly important roles in gene regulation and developmental variation across diverse organisms that do not alter genetic background. Here, to investigate whether DNA methylation could be associated with different phenotypic consequences in the two forms of T. urticae, we surveyed the genome-wide cytosine methylation status and expression level of DNA methyltransferase 3 (Tudnmt3) throughout their entire life cycle. Methylation-sensitive amplification polymorphism (MSAP) analyses of 585 loci revealed variable methylation patterns in the different developmental stages. In particular, principal coordinates analysis (PCoA) indicates a significant epigenetic differentiation between female adults of the two forms. The gene expression of Tudnmt3 was detected in all examined developmental stages, which was significantly different in the adult stage of the two forms. Together, our results reveal the epigenetic distance between the two forms of T. urticae, suggesting that DNA methylation might be implicated in different developmental demands, and contribute to different phenotypes in the adult stage of these two forms.

Comparative transcriptomes and reciprocal best hit analysis revealed potential pigment genes in two color forms of Tetranychus urticae.

Tetranychus urticae Koch is a worldwide agricultural pest. There are two color forms: red and green. The molecular mechanism underlying this color variation is unknown. To elucidate the mechanism, we characterized differentially expressed pigment pathway genes shared in the transcriptomes of these two forms using RNA sequencing and reciprocal best hit analysis. Differentially expressed pigment pathway genes were determined by qRT-PCR to confirm the accuracy of RNA-Seq. The transcriptomes revealed 963 differentially expressed genes (DEGs), of which 687 DEGs were higher in the green form. KEGG enrichment analysis revealed carotenoid biosynthesis genes in T. urticae. Reciprocal best hit analysis revealed 817 putative pigment pathway genes, 38 of which were differentially expressed and mainly classified into four categories: heme, melanin, ommochrome and rhodopsin. Phylogenetic analysis of homologous ommochrome genes showed that tetur09g01950 is closely related to Ok. This study revealed putative pigment pathway genes in the two forms of T. urticae, and might provide a new resource for understanding the mechanism of color variation.

Infection Rate Assay by Nested PCR and the Phylogenetic Analysis of Himetobi P Virus in the Main Pests of Rice-Wheat Cropping Systems.

Himetobi P virus (HiPV) is an ssRNA in the family Dicistroviridae that infects rice pests belonging to Hemiptera. To determine its host range, a nested PCR method was designed to detect HiPV in some of the main rice pests (Hemiptera) in eastern China. The incidence of infection in the grain aphid Sitobion avenae Fabricius (Hemiptera: Aphididae) was low (3%), while high incidences of infection occurred in the planthoppers Laodelphax striatellus (Fallén) (Hemiptera: Delphacidae) (100%) and Nilaparvata lugens (Hemiptera: Delphacidae) (51%) and in the leafhoppers Cicadella viridis (Hemiptera: Cicadellidae) (90%) and Nephotettix cincticeps (Hemiptera: Cicadellidae) (57%). Phylogenetic analysis by maximum likelihood tree and median-joining networks implied the HiPVs from the same hosts were genetically close. Neutral equilibrium evolution for the polymorphism data was tested by the Tajima's D test and by Fu and Li's D and F tests. Test values were negative, which indicates a selection on the HiPV haplotypes. We sequenced the complete genome sequence of HiPV to look for evidence of recombination. We identified a recombination event in which two genomes recombined in the region of ORF2. The two open reading frames of the HiPV had been selected with low Ka/Ks ratios compared with two previous genome sequences.

Expression level and immunolocalization of de novo methyltransferase 3 protein (TuDNMT3) in adult females and males of the two-spotted spider mite, Tetranychus urticae.

DNA methylation is an epigenetic mechanism for regulating developmental and other important processes in eukaryotes. Several essential components of the DNA methylation machinery have been identified, such as DNA methyltransferases. In the two-spotted spider mite, Tetranychus urticae Koch, we have identified one DNA methyltransferase 3 gene (Tudnmt3) and tentatively investigated its potential role in adult females and males. Here, to better elucidate the functional role of Tudnmt3, its protein structure, expression and localization were subjected to more detailed analyses. Bioinformatic analyses clearly showed that the structure of TuDNMT3 was highly conserved, with several vital amino acid residues for the activation and stabilization of its confirmation. Western blot analyses revealed that this protein was expressed in both genders, with higher expression in adult females, which was inconsistent with the gene expression, suggesting translational regulation of Tudnmt3. Subsequent immunodetection provided supportive evidence for higher expression of the TuDNMT3 protein in adult females and indicated that this protein was generally localized in the cytoplasm and that its expression was predominantly confined to the genital region of spider mites, strengthening the hypothesis that de novo methylation mediated by Tudnmt3 in gonad development or gametogenesis has a different mechanism from maintenance methyltransferase.

The complete mitochondrial genomes of six species of Tetranychus provide insights into the phylogeny and evolution of spider mites.

Many spider mites belonging to the genus Tetranychus are of agronomical importance. With limited morphological characters, Tetranychus mites are usually identified by a combination of morphological characteristics and molecular diagnostics. To clarify their molecular evolution and phylogeny, the mitochondrial genomes of the green and red forms of Tetranychus urticae as well as T. kanzawai, T. ludeni, T. malaysiensis, T. phaselus, T. pueraricola were sequenced and compared. The seven mitochondrial genomes are typical circular molecules of about 13,000 bp encoding and they are composed of the complete set of 37 genes that are usually found in metazoans. The order of the mitochondrial (mt) genes is the same as that in the mt genomes of Panonychus citri and P. ulmi, but very different from that in other Acari. The J-strands of the mitochondrial genomes have high (∼ 84%) A+T contents, negative GC-skews and positive AT-skews. The nucleotide sequence of the cox1 gene, which is commonly used as a taxon barcode and molecular marker, is more highly conserved than the nucleotide sequences of other mitochondrial genes in these seven species. Most tRNA genes in the seven genomes lose the D-arm and/or the T-arm. The functions of these tRNAs need to be evaluated. The mitochondrial genome of T. malaysiensis differs from the other six genomes in having a slightly smaller genome size, a slight difference in codon usage, and a variable loop in place of the T-arm of some tRNAs by a variable loop. A phylogenic analysis shows that T. malaysiensis first split from other Tetranychus species and that the clade of the family Tetranychoidea occupies a basal position in the Trombidiformes. The mt genomes of the green and red forms of T. urticae have limited divergence and short evolutionary distance.