Synergistic effect of Mn doping and hollow structure boosting Mn-CoP/Co2P nanotubes as efficient bifunctional electrocatalyst for overall water splitting.

The sluggish kinetic of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) severely hampers the commercial application of electrochemical water splitting, promoting the urgent exploration of high-efficient bifunctional electrocatalysts. Heteroatom doping and structure engineering have been identified as the most effective strategies to boost the catalytic activity of electrocatalysts. Herein, Mn doping and hollow structure were integrated in the design of Co-based transition metal phosphide catalyst to prepare Mn-CoP/Co2P nanotubes (denoted as Mn-CP NTs) by a facile template-free method. Confirmed by characterization analysis, the introduced Mn species were in high dispersion in the regular CoP/Co2P hollow tubular framework. Such a favorable design in composition and structure effectively boosted the catalytic activity of Mn-CP NTs toward electrochemical water splitting. The Mn-CP NTs showed superior HER and OER activity demonstrated by the low overpotentials of 82 mV (vs HER) and 309 mV (vs OER) at the current density of 10 mA cm-2, as well as the satisfactory durability. When used as both cathode and anode in electrolyzer for overall water splitting, only a low cell voltage of 1.67 V was required for the Mn-CP NTs to drive 10 mA cm-2, accompanied with excellent stability confirmed by over 50 h test.

[Corrigendum] miR­29b overexpression induces cochlear hair cell apoptosis through the regulation of SIRT1/PGC­1α signaling: Implications for age­related hearing loss.

Subsequently to the publication of the above paper, an interested reader drew to the authors' attention that the bar charts shown in Fig. 4A and B, which were intending to have shown the RT­qPCR and western blot analyses of SIRT1 and PGC­1α in HEI­OC1 cells, respectively, under different experimental conditions were apparently identical. Similarly, in Fig. 5, the histograms shown in Fig. 5C and D, which were intending to have shown the RT­qPCR and western blot analyses, respectively, of SIRT1 and PGC­1α in HEI­OC1 cells subjected to different treatments were also apparently identical. The authors have re­examined their data, and realize that the data properly belonging to the protein expression levels had been wrongly used to show the mRNA levels, and therefore Figs. 4A and 5C were presented incorrectly in these figures. The revised versions of Figs. 4 and 5, containing the correct data for the RT­qPCR experiments in Figs. 4A and 5C, are shown on the next page. These errors did not affect the major conclusions reported in the paper. All the authors have agreed to this corrigendum, and thank the Editor of International Journal of Molecular Medicine for allowing them the opportunity to publish this. The authors regret these errors went unnoticed during the compilation of the figures in question, and apologize to the readership for any confusion that this may have caused. [the original article was published in International Journal of Molecular Medicine 38: 1387­1394, 20186 DOI: 10.3892/ijmm.2016.2735].

Atrial Natriuretic Peptide Promotes Neurite Outgrowth and Survival of Cochlear Spiral Ganglion Neurons in vitro Through NPR-A/cGMP/PKG Signaling.

Sensorineural hearing loss (SNHL) is a dominant public health issue affecting millions of people around the globe, which is correlated with the irreversible deterioration of the hair cells and spiral ganglion neurons (SGNs) within the cochlea. Strategies using bioactive molecules that regulate neurite regeneration and neuronal survival to reestablish connections between auditory epithelium or implanted electrodes and SGN neurites would become attractive therapeutic candidates for SNHL. As an intracellular second messenger, cyclic guanosine-3',5'-monophosphate (cGMP) can be synthesized through activation of particulate guanylate cyclase-coupled natriuretic peptide receptors (NPRs) by natriuretic peptides, which in turn modulates multiple aspects of neuronal functions including neuronal development and neuronal survival. As a cardiac-derived hormone, atrial natriuretic peptide (ANP), and its specific receptors (NPR-A and NPR-C) are broadly expressed in the nervous system where they might be involved in the maintenance of diverse neural functions. Despite former literatures and our reports indicating the existence of ANP and its receptors within the inner ear, particularly in the spiral ganglion, their potential regulatory mechanisms underlying functional properties of auditory neurons are still incompletely understood. Our recently published investigation revealed that ANP could promote the neurite outgrowth of SGNs by activating NPR-A/cGMP/PKG cascade in a dose-dependent manner. In the present research, the influence of ANP and its receptor-mediated downstream signaling pathways on neurite outgrowth, neurite attraction, and neuronal survival of SGNs in vitro was evaluated by employing cultures of organotypic explant and dissociated neuron from postnatal rats. Our data indicated that ANP could support and attract neurite outgrowth of SGNs and possess a high capacity to improve neuronal survival of SGNs against glutamate-induced excitotoxicity by triggering the NPR-A/cGMP/PKG pathway. The neuroregenerative and neuroprotective effects of ANP/NPRA/cGMP/PKG-dependent signaling on SGNs would represent an attractive therapeutic candidate for hearing impairment.

Atrial Natriuretic Peptide Improves Neurite Outgrowth from Spiral Ganglion Neurons In Vitro through a cGMP-Dependent Manner.

The spiral ganglion neurons (SGNs) are the primary afferent neurons in the spiral ganglion (SG), while their degeneration or loss would cause sensorineural hearing loss. As a cardiac-derived hormone, atrial natriuretic peptide (ANP) plays a critical role in cardiovascular homeostasis through binding to its functional receptors (NPR-A and NPR-C). ANP and its receptors are widely expressed in the mammalian nervous system where they could be implicated in the regulation of multiple neural functions. Although previous studies have provided direct evidence for the presence of ANP and its functional receptors in the inner ear, their presence within the cochlear SG and their regulatory roles during auditory neurotransmission and development remain largely unknown. Based on our previous findings, we investigated the expression patterns of ANP and its receptors in the cochlear SG and dissociated SGNs and determined the influence of ANP on neurite outgrowth in vitro by using organotypic SG explants and dissociated SGN cultures from postnatal rats. We have demonstrated that ANP and its receptors are expressed in neurons within the cochlear SG of postnatal rat, while ANP may promote neurite outgrowth of SGNs via the NPR-A/cGMP/PKG pathway in a dose-dependent manner. These results indicate that ANP would play a role in normal neuritogenesis of SGN during cochlear development and represents a potential therapeutic candidate to enhance regeneration and regrowth of SGN neurites.

HDAC inhibitor sodium butyrate prevents allergic rhinitis and alters lncRNA and mRNA expression profiles in the nasal mucosa of mice.

Our previous study demonstrated that intranasal administration of histone deacetylase inhibitor sodium butyrate (NaB) exhibits therapeutic effects on a mouse model of allergic rhinitis (AR). However, whether NaB is effective on AR when administered orally and prophylactically, as well as its potential effects on gene expression, remained unknown. The present study aimed to investigate the preventive effect of NaB on AR when added to the diet of newly weaned mice and to evaluate the changes in long non­coding (lnc)RNA and mRNA expression profiles in the nasal mucosa. Mice were randomly divided into three groups as follows: i) Control (C) group, (no treatment); ii) AR group [treated with ovalbumin (OVA)]; and iii) NaB + AR group (treated with OVA and NaB). The NaB + AR group was administered NaB in their feed (30 g/kg chow), whereas the other two groups were fed normal feed between 3 and 6 weeks of age. At 7 weeks of age, OVA administration was initiated to induce AR in the AR and NaB + AR groups. Following model establishment, behavioral assessments, western blotting and gene expression analysis were performed. NaB exhibited a preventive effect in the murine AR model, diminished the increases in histone deacetylase 1 (HDAC1) and HDAC8 expression and increased OVA­induced acetylation of histone H3 at lysine 9. In addition, NaB increased the AR­associated low expression of interleukin 2 (IL­2), interferon Î³ and IL­17 and decreased the expression of IL­4, IL­5 and transforming growth factor ß1. Gene Ontology and pathway analyses revealed the top 10 pathways among the groups. Octamer­binding transcription factor 1, ecotropic viral integration site 1 and paired box 4 were predicted to be target genes of lncRNA (NONMMUT057309). Thus, NaB may exhibit a preventive effect on AR. Additionally, the lncRNA and mRNA expression profiles in the nasal mucosa of mice with AR differed significantly following NaB treatment. These results may provide insights into the pathogenesis of AR and suggest new treatment targets.

Improved Photovoltaic Effect of p-i-n Structured BiFeO3 Film Deposited by Radio-Frequency Magnetron Sputtering.

Pure phase polycrystalline BiFeO3 film was deposited onto FTO substrate by RF magnetron sputtering method. SEM result shows that BiFeO3 film has the obvious porosity and large clusters which lead to the poor ferroelectric and photovoltaic properties in FTO/BiFeO3/Ag device. However, these properties are improved in p-i-n structured FTO/TiO2/BiFeO3/HTM/Ag device by incorporating the electron and hole transport materials. The hysteresis loop measurement demonstrates the excellent ferroelectric property with large remnant polarization (2Pr = 180 µC/cm²) and low leakage current. The J-V curve shows the short-circuit current density is dozens of times larger than that of FTO/BiFeO3/Ag device. Moreover, the photovoltaic output depends on the poling field where the positive poling improves the short-circuit current density to -85 µA/cm2 and the negative poling reduces both the photocurrent and photovoltage. It is believed that the ferroelectric polarization plays a dominant role in the photovoltaic effect.

Photovoltaic Effect in BiFeO3 Film Deposited by RF Magnetron Sputtering.

A polycrystalline BiFeO3 film was deposited on ITO substrate by RF magnetron sputtering method. Small crystallite size and compact structure are obtained for BiFeO3 film which has the excellent ferroelectric properties. The measured photovoltaic response reveals an open-circuit voltage of ~0.52 V and a short-circuit current density of ~10 µA/cm² under the illumination of 100 mW/cm² irradiance. Moreover, a tunable photovoltaic effect with light illumination is observed under different voltage sweep mode. High initial sweep voltage can enhance the photovoltaic effect largely, however, the photovoltaic response decreases with the increase of voltage sweep interval. The results indicate the ferroelectric polarization plays an important role in the photovoltaic effect.

Inhibition of DHCR24 increases the cisplatin-induced damage to cochlear hair cells in vitro.

Hearing loss is a common sensory disorder that affects more than 360 million people worldwide, and is primarily caused by the loss of hair cells (HCs). Ototoxic drugs, viral infections, genetic predisposition, aging or noise all damage HCs. 3ß-hydroxysteroid-Δ24 reductase (DHCR24), one enzyme in the cholesterol biosynthetic pathway, is involved in inflammation, oxidative stress and neuroprotection. However, researchers have not determined whether DHCR24 is present in the cochlea and the mechanism by which it exerts its regulatory effect on HC loss. In the present study, we analyzed DHCR24 expression in the postnatal day 1 (P1) rat cochlea and found that DHCR24 was localized in HCs of the organ of Corti. Next, exposure to cisplatin caused HC loss in cochlear organotypic cultures. Then, we inhibited DHCR24 expression with U18666A and observed significantly increased cisplatin-induced damage of cochlear HCs. These findings were consistent with the observed increase in DHCR24 expression in response to cisplatin treatment, and U18666A significantly decreased DHCR24 expression. Finally, DHCR24 inhibition increased the levels of reactive oxygen species and cleaved caspase-3 after cisplatin-induced injury. Collectively, DHCR24 may play a significant role in regulating auditory function and potentially represents a new therapeutic target for the treatment of cisplatin-induced ototoxicity.

Electrical Properties of Ba0.96Ca0.04Ti0.90Sn0.10O3 Lead-Free Ceramics with the Addition of Nano-CeO2.

Well dispersed CeO2 nanoparticles are prepared by azeotropic co-precipitation method. (Ba0.96Ca0.04)(Ti0.90Sn0.10)O3 lead-free piezoelectric ceramics doped with nano-CeO2 (x =0 mol%, 0.03 mol%, and 0.07 mol%) and micro-CeO2 (x = 0.03 mol%) are prepared at 1430 °C for 2 h by the conventional solid state sintering method. XRD diffraction indicates that all components have typical perovskite structure. Both doping of nano-CeO2 and micro-CeO2 can inhibit grain growth. And the average grain size decreased apparently with the increase of nano-CeO2 amount. All the samples exhibit typical diffuse phase transition behavior. The optimized electrical performances are obtained at x = 0.03 mol% with d33 = 512 pC/N, kp = 41.5%, and Pr = 14.00 µC/cm².

Outer hair cells isolation from postnatal Sprague-Dawley rats.

Outer hair cells (OHCs) damage is a general phenomenon in clinical disorders such as noise-induced hearing loss and drug-induced hearing loss. In order to elucidate the mechanism underlying these disorders, OHCs - its diseased region needs to be deeply investigated. However, OHCs array on the basilar membrane which contains massive cells with different types. Therefore, to isolate OHCs from this huge population is significant for revealing its pathological and molecular changes during disease processing. In the present study, we tried to isolate OHCs from the commonly used animal model -Sprague-Dawley (SD) rats. By separating outer hair cells from SD rats with different day ages, we found that 9 days after birth was a suitable time for the separation of the OHCs. At this time, the number of OHCs isolated from rats was large, and the cell morphology was typical of cylindrical shape. OHCs isolated using this method are histologically suitable and quantitatively adequate for molecular biological and electrophysiological analyses.

[Recurrent low frequency sensorineural deafness].

Low frequency sensorineural deafness is a common subtype of idiopathic sudden deafness. Certain patients suffered recurrent attacks without vertigo, much alike Meniere's disease. Few of them developed into definite Meniere's disease during long-term follow-up in many clinical studies. Although the pathophysiology of recurrent low frequency deafness is yet unknown, the desease is considered associated with early state of endolymphatic hydrops or migraine. Otologists shall be aware of its clinical course and careful explanation is necessary at time of initial informed consent.

Decreased expression of TERT correlated with postnatal cochlear development and proliferation reduction of cochlear progenitor cells.

Cochlear progenitor cells are considered as one of the best candidates for hair cell regeneration, thus, the regulation of cochlear progenitor cell proliferation has become a focus in this field. Several genes expressed in the inner ear during postnatal development have been demonstrated to be involved in maintaining the proliferative potential of progenitor cells, but the mechanism for regulating the proliferation and differentiation of cochlear progenitor cells remains poorly understood. Telomerase reverse transcriptase (TERT) has rate limiting telomerase activity and the overexpression of TERT has been shown to promote cell proliferation in series of cell lines. The aim of the present study was to evaluate the expression of TERT in the postnatal development of the cochlea and progenitor cells. The results demonstrated that TERT was expressed in the basilar membranes during the first postnatal week. In vitro, TERT expression in progenitor cells reached a maximum at day 4 after culture and decreased as the culture time prolonged or the cell passage number increased. These results led us to hypothesize that TERT may be involved in the development of the cochlea and in maintaining the proliferation ability of progenitor cells.

De novo assembly and functional annotations of the transcriptome of Metorchis orientalis (trematoda: Opisthorchiidae).

Metorchis orientalis is a neglected zoonotic parasite, living in the gallbladder and bile duct of poultry and some mammals as well as humans. In spite of its economic and medical importance, the information known about the transcriptome and genome of M. orientalis is limited. In this study, we performed de novo sequencing, transcriptome assembly and functional annotations of the adult M. orientalis, obtained about 77.4 million high-quality clean reads, among which the length of the transcript contigs ranged from 100 to 11,249 nt with mean length of 373 nt and N50 length of 919 nt. We then assembled 31,943 unigenes, of which 20,009 (62.6%) were annotated by BLASTn and BLASTx searches against the available database. Among these unigenes, 19,795 (62.0%), 3407 (10.7%), 10,620 (33.2%) of them had significant similarity in the NR, NT and Swiss-Prot databases, respectively; 5744 (18.0%) and 4678 (14.6%) unigenes were assigned to GO and COG, respectively; and 9099 (28.5%) unigenes were identified and mapped onto 256 pathways in the KEGG Pathway database. Furthermore, we found that 98 (1.08%) unigenes were related to bile secretion and 5 (0.05%) to primary bile acid biosynthesis pathways category. The characterization of these transcriptomic data has implications for the better understanding of the biology of M. orientalis, and will facilitate the development of intervention agents for this and other pathogenic flukes of human and animal health significance.

Mitochondrial DNA Evidence Supports the Hypothesis that Triodontophorus Species Belong to Cyathostominae.

Equine strongyles, the significant nematode pathogens of horses, are characterized by high quantities and species abundance, but classification of this group of parasitic nematodes is debated. Mitochondrial (mt) genome DNA data are often used to address classification controversies. Thus, the objectives of this study were to determine the complete mt genomes of three Cyathostominae nematode species (Cyathostomum catinatum, Cylicostephanus minutus, and Poteriostomum imparidentatum) of horses and reconstruct the phylogenetic relationship of Strongylidae with other nematodes in Strongyloidea to test the hypothesis that Triodontophorus spp. belong to Cyathostominae using the mt genomes. The mt genomes of Cy. catinatum, Cs. minutus, and P. imparidentatum were 13,838, 13,826, and 13,817 bp in length, respectively. Complete mt nucleotide sequence comparison of all Strongylidae nematodes revealed that sequence identity ranged from 77.8 to 91.6%. The mt genome sequences of Triodontophorus species had relatively high identity with Cyathostominae nematodes, rather than Strongylus species of the same subfamily (Strongylinae). Comparative analyses of mt genome organization for Strongyloidea nematodes sequenced to date revealed that members of this superfamily possess identical gene arrangements. Phylogenetic analyses using mtDNA data indicated that the Triodontophorus species clustered with Cyathostominae species instead of Strongylus species. The present study first determined the complete mt genome sequences of Cy. catinatum, Cs. minutus, and P. imparidentatum, which will provide novel genetic markers for further studies of Strongylidae taxonomy, population genetics, and systematics. Importantly, sequence comparison and phylogenetic analyses based on mtDNA sequences supported the hypothesis that Triodontophorus belongs to Cyathostominae.

Metacercaria Infection Status of Fishborne Zoonotic Trematodes, Except for Clonorchis sinensis in Fish from the Heilongjiang Province, China.

To investigate the metacercarial infections of fishborne zoonotic trematodes (FZT), a total of 6815 freshwater fish (in representing 13 species of 5 families) were collected from Songhua river (n = 2636), Nenjiang river (n = 1935), Mudanjiang river (n = 301), and other lakes or ponds (n = 1943) in 36 representative regions in Heilongjiang Province, China, from August 2012 to December 2015. Metacercariae of four FZT species, that is, Clonorchis sinensis, Metorchis orientalis, Isthmiophora hortensis, and Metagonimus yokogawai, metacercariae were detected in the examination by the artificial digestion method. As the partial data for C. sinensis were previously reported, the remaining three FZT species are to be treated in this study. The overall prevalence of M. orientalis, I. hortensis, and M. yokogawai, metacercariae was 10.54%, 0.28%, and 1.35%, respectively. Metacercariae of M. orientalis were detected in seven fish species, that is, Pseudorasbora parva, Hemiculter leucisculus, Saurogobio dabryi, Rhynchocypris lagowskii, Carassius auratus, Rhodeus ocellatus and Perccottus glehnii. Their prevalences were the highest in false dace, P. parva (26.81%), and in fish from Songhua river (17.94%). Metacercariae of I. hortensis were detected in only one fish species, Misgurnus anguillicaudatus, from Nenjiang river only. Metacercariae of M. yokogawai were detected in three fish species, that is, P. parva, H. leucisculus and S. dabryi. Their prevalences were the highest in sharpbelly, H. leucisculus (6.05%), and in fish from Mudanjiang river (5.65%). This study first demonstrated the existence of M. orientalis, I. hortensis, and M. yokogawai in freshwater fish from Heilongjiang Province, posing a major public health concern. Eight fish species, namely M. anguillicaudatus, P. parva, H. leucisculus, S. dabryi, R. lagowskii, C. auratus, R. ocellatus, and P. glehnii, cannot be eaten raw. Moreover, the findings of this study not only extended the second intermediate host range of FZT, but also improve the information of the distribution of FZT in China.

Genetic variation between and within Triodontophorus brevicauda and Triodontophorus nipponicus revealed by analyses of mtDNA and rDNA gene sequences.

Triodontophorus spp. parasitizes the large intestine of equine, causing strongylid diseases. The present study assessed genetic variation in five gene regions within and between Triodontophorus brevicauda and Triodontophorus nipponicus from Heilongjiang Province and the Inner Mongolia Autonomous region. The five gene markers were three mitochondrial (mt) genes, cytochrome c oxidase subunit I (cox1), NADH dehydrogenase subunit 5 (nad5), cytochrome b (cytb); and two ribosomal RNA genes, the internal transcribed spacer 1 (ITS1) and the internal transcribed spacer 2 (ITS2). Partial (p) sequences of cox1, nad5, cytb and the complete ITS rDNA region were PCR amplified from individual nematodes, and the amplicons were subjected to sequencing in both directions. The size of the three mt genes is identical in both species: 761 bp (p cox1), 505 bp (pnad5) and 562 bp (pcytb); the length of the two ribosomal genes is different: 376 bp and 370 bp (ITS1), and 333 bp and 322 bp (ITS2), respectively. Intraspecific variation between T. brevicauda and T. nipponicus was 0-1.5% and 0-1.1% for pcox1, 0-2.0% and 0-2.0% for pnad5, 0-1.4% and 0-2.2% for pcytb, 0-0.8% and 0-1.1% for ITS1 and 0-0.9% and 0-2.2% for ITS2. Interspecific variation within the nematodes was 13.5-14.3% for pcox1, 15.5-18.7% for pnad5, 16.7-18.6% for pcytb, 11.5-13.1% for ITS1 and 16.0-18.4% for ITS2. Phylogenetic analyses based on the combined mt gene sequences, as well as with the ITS sequences, show each species forming a monophyletic group of individuals. However, samples of different species from the same geographical origin did not always cluster together. These results provide valuable information for further studies of systematics and population genetics of the genus Triodontophorus.

Minocycline attenuates noise-induced hearing loss in rats.

Noise-induced hearing loss (NIHL) is a serious health concern and prevention of hair cell death or therapeutic intervention at the early stage of NIHL is critical to preserve hearing. Minocycline is a semi-synthetic derivative of tetracycline and has been shown to have otoprotective effects in ototoxic drug-induced hearing impairment, however, whether minocycline can protect against NIHL has not been investigated. The present study demonstrated elevated ABR (auditory brainstem response) thresholds and outer hair cell loss following traumatic noise exposure, which was mitigated by intraperitoneal administration of minocycline (45mg/kg/d) for 5 consecutive days. In conclusion, the present study demonstrated that minocycline, a clinically approved drug with a good safety profile, can attenuate NIHL in rats and may potentially be used for treatment of hearing loss in clinic.

Complete mitochondrial genome of parasitic nematode Cylicocyclus nassatus and comparative analyses with Cylicocyclus insigne.

Cylicocyclus nassatus is a common and important parasite in the large intestine of equine. In this study, the complete mitochondrial (mt) genome sequence of C. nassatus was determined and comparatively analyzed with Cylicocyclus insigne. The mt genome size of C. nassatus was 13,846 bp, 18 bp longer than that of C. insigne. The circular mt genome includes 12 protein-coding genes, two rRNA genes, 22 tRNA genes and two non-coding regions. All the genes are transcribed in the same direction and gene arrangement is consistent with that of gene arrangement 3 (GA3). The overall sequence difference between the two complete mt genomes was 10.7%. For the 12 protein-coding genes, the comparison between C. nassatus and C. insigne revealed sequence divergence at both the nucleotide (6.3-13.0%) and amino acid (0.8-6.6%) levels. The nucleotide lengths of the 12 protein-coding genes were the same, except for cox3 which was longer in C. insigne. Phylogenetic analysis based on the concatenated amino acid sequence of the 12 protein-coding genes was performed using all the Strongylidae nematodes of the horse available in the GenBank. Phylogenetic analysis showed that C. nassatus and C. insigne clustered together with very high nodal support and the genus Cylicocyclus was closer to the genus Triodontophorus than to genus Strongylus. The mtDNA data determined in this study provides novel genetic markers for further studies on the identification, population genetics and molecular epidemiology of the genus Cylicocyclus.

miR-29b overexpression induces cochlear hair cell apoptosis through the regulation of SIRT1/PGC-1α signaling: Implications for age-related hearing loss.

It has been reported that the degeneration of cochlear hair cells is the typical cause of presbycusis (or age-related hearing loss). However, the molecular mechanisms that mediate cochlear hair cell apoptosis are not yet fully understood and there is no effective treatment for this disorder. MicroRNAs (miRNAs or miRs) have been increasingly shown to be associated with age-related diseases and are emerging as promising therapeutic targets. In this study, we investigated whether miR-29b is involved in the degeneration of cochlear hair cells. To examine our hypothesis, nuclear staining and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) were used to quantify the hair cell counts. RT-qPCR and western blot analysis were used to examine miR-29b/sirtuin 1 (SIRT1)/proliferator-activated receptor-gamma coactivator 1α (PGC­1α) signaling in cochlear hair cells. We found that there was a significant degeneration of cochlear hair cells and a higher expression of miR-29b in aged C57BL/6 mice compared with young mice. There was also an age-related decrease in the expression of SIRT1 and PGC­1α. In the inner ear cell line, HEI-OC1, miR-29b overexpression (by transfection with miR-29b mimic) inhibited SIRT1 and PGC­1α expression, leading to an increase in mitochondrial dysfunction and apoptosis. Moreover, the inhibition of miR-29b (by transfection with miR-29b inhibitor) increased SIRT1 and PGC­1α expression, while it decreased apoptosis. Taken together, our findings support a link between age-related cochlear hair cell apoptosis and miR-29b/SIRT1/PGC­1α signaling, which may present an attractive pharmacological target for the development of novel drugs for the treatment of age-related hearing loss.

Complete mitochondrial genomes of Dermacentor silvarum and comparative analyses with another hard tick Dermacentor nitens.

Ticks are obligate blood-sucking ectoparasites of a wide range of vertebrates. They can transmit a range of pathogens that cause economic losses to livestock production as well as human disease. In the present study, the complete mitochondrial (mt) genome of Dermacentor silvarum was determined. The mt genome is 14,945 bp in length contains 37 genes, including 13 are protein-coding genes (cox1-3, nad1-6, nad4L, cytb, atp6 and atp8), two ribosomal RNA genes and 22 transfer RNA genes. The nucleotide composition of the D. silvarum mt genome was A + T biased at 78.78%; T was the most abundant nucleotide and G the least abundant. The mt genome of D. silvarum was 106 bp longer than that of Dermacentor nitens and the arrangements of two genomes were identical. For the 13 protein-coding genes, comparison between D. silvarum and D. nitens revealed sequence divergence at both the nucleotide (15.46-35.14%) and amino acid (6.05-48.98%) levels. Among them, cox1 was the most conserved gene, while atp8 was the least conserved. The lengths of the 13 protein-coding genes were the same or similar, except for cytb which was significantly longer in D. silvarum than in D. nitens. The mtDNA contained a variable repeat region consisting of a "similar to nad1" motif that was repeated three times, and the "Tick-box" motifs were also found. The overall difference between the nucleotide sequences of the two complete mt genomes was 21.4%. The mtDNA data presented in this study provide a rich resource for further studies on the phylogenetics, population genetics, and molecular epidemiology of ticks.