Morphology, genetic characterization and phylogeny of Moniliformis tupaia n. sp. (Acanthocephala: Moniliformidae) from the northern tree shrew Tupaia belangeri chinensis Anderson (Mammalia: Scandentia).

A new species of Moniliformis, M. tupaia n. sp. is described using integrated morphological methods (light and scanning electron microscopy) and molecular techniques (sequencing and analysing the nuclear 18S, ITS, 28S regions and mitochondrial cox1 and cox2 genes), based on specimens collected from the intestine of the northern tree shrew Tupaia belangeri chinensis Anderson (Scandentia: Tupaiidae) in China. Phylogenetic analyses show that M. tupaia n. sp. is a sister to M. moniliformis in the genus Moniliformis, and also challenge the systematic status of Nephridiacanthus major. Moniliformis tupaia n. sp. represents the third Moniliformis species reported from China.

Molecular characterization and phylogenetic analysis of Argas persicus (Oken, 1818) (Acari: Argasidae) from domestic birds in eastern Algeria.

Argas persicus (the fowl tick) is a species of soft tick commonly associated with poultry farms. It has a wide geographic distribution and colonizes different climate regions. Morphological identification of A. persicus has been reported worldwide, but genetic data regarding its molecular characterization is limited. The present study provides data for morphological identification and genetic characterization of A. persicus collected from domestic birds in traditional farms from east Algeria (Setif region). Additionally, A. persicus samples originating from Gansu province in China were included for comparative molecular study. In total, 1518 ticks collected from 30 infested farms were examined and morphologically identified as A. persicus. Furthermore, the 14 tick samples obtained from China were morphologically identified as A. persicus. Molecular analysis of 30 ticks from Algeria (one tick from each infested farm) and the 14 Chinese samples based on PCR, sequencing, and phylogenetic analysis of three mitochondrial genetic markers (16S rRNA, 12S rRNA, and cox1) confirmed morphological results where all samples belonged to the A. persicus group. However, phylogenetic analysis showed that all Algerian samples and two Chinese samples belong to A. persicus sensu stricto (s.s.), while the remaining Chinese samples represented A. persicus sensu lato (s.l.) (divergent lineage). The present study confirms the occurrence of A. persicus s.s. both in Algeria and China, as well as provides novel molecular data for a distinct Chinese lineage of A. persicus.

The genome-wide characterization and associated cold-tolerance function of the superoxide dismutase in the cold response of the tick Haemaphysalis longicornis.

Accumulating evidence suggests that superoxide dismutase (SOD) is the first line of antioxidant defense in organisms and plays an important role in scavenging reactive oxygen species produced during environmental stress. However, limited information is available regarding the response of SOD genes to cold stress in ticks. Therefore, in the present study, SOD genes were cloned and identified from the genome of Haemaphysalis longicornis, and the function of SOD during the cold response was further explored. Seven SOD genes were characterized: HlCCS1, HlCCS2, HlMSD, HlCSD1, HlCSD2, HlCSD3, and HlCSD4. Bioinformatics analysis showed that HlCCS1 and HlCCS2 are copper chaperones of SODs. HlCSD1-HlCSD4 belong to the Cu/Zn SOD, whereas HlMSD belongs to the Mn SOD gene family. Fluorescence quantitative PCR showed that the expression of HlCCS2, HlMSD, and HlCSD1-3 was upregulated, whereas HlCCS1 and HlCSD4 were downregulated during the cold response of H. longicornis. Western blotting confirmed changes in the relative expression of HlCSD3 and HlMSD in H. longicornis after cold treatment. Mortality of H. longicornis increased significantly after dsRNA injection of HlCCS2, HlMSD, HlCSD1, and HlCSD3. The above results show that SODs have different regulatory functions during the cold response in H. longicornis, and there might be an interaction between treatment temperature and duration. Furthermore, the results lay a foundation for subsequent research on the molecular mechanism of cold tolerance in H. longicornis and shed light on the population distribution and diffusion limit of ticks.

The new Haemaphysalis longicornis genome provides insights into its requisite biological traits.

Ticks are a large group of blood-feeding arthropods that transmit multiple human and animal pathogens and are hence of importance to public health. The tick Haemaphysalis longicornis is associated with the transmission of multiple human pathogens in Asia, and recently found invading to the United States. Here, we report the sequencing, assembly and annotation of the 3.16 gigabase genome of this species, which is larger than the previous assembled one. The present Haemaphysalis longicornis genome was characterized by 6519 scaffolds, 24,189 protein-coding genes and a high proportion of simple sequence repeats (54.72%). By genomic assembly and comparative genomic analysis, we characterized the key genes that play essential roles in iron metabolism, detoxification, and freeze tolerance of H. longicornis. Furthermore, a total of 79 endogenous viral elements were identified within the genome, which might have had a considerable impact on its evolution. Decoding the H. longicornis genome not only provides insight into the genetic underpinnings of specific biological processes but also offers the basis for the subsequent integrated control of ticks and tick-borne diseases.

Proteomic analysis suggests that monoterpenes in lemongrass disrupt Ca2+ homeostasis in Haemaphysalis longicornis leading to mitochondrial depolarization and cytotoxicity.

Complex mixtures of bioactive ingredients in plant essential oils present complex chemistries which involve different modes of action. An increasing body of scientific reports has recently focused on the acaricidal activities of plant essential oils attributed to their monoterpene components, but information about their underlying molecular mechanism of action is scarce. Here, after the chemical analysis of lemongrass oil, a proteomic analysis of the ovary, salivary gland, and midgut of Haemaphysalis longicornis exposed to Cymbopogon citratus (lemongrass) essential oil was performed via data-independent acquisition mass spectrometry (DIA-MS) technology to further elucidate the molecular mechanisms involved. Pathway analysis reveals the activation of metabolic pathways mediated by oxidoreductases and transferases. Furthermore, the upregulation of various calcium-associated proteins and the upregulation of cytochrome c1, cytochrome c oxidase polypeptide IV, and programmed cell death protein 6-like isoform X1 suggest a cytotoxic mode of action via the formation of reactive oxygen species (ROS), mitochondrial Ca2+ overload, mitochondrial uncoupling, and depolarization, and ATP depletion leading to either apoptotic or necrotic death. Morphological alterations observed after the RNAi of a major detoxification enzyme (glutathione S-transferase) merit further investigation. Hence, the cytotoxic mode of action exhibited by C. citratus oil could be vital for the development of eco-friendly acaricide.

Managing Methane Emissions in Abandoned Coal Mines: Comparison of Different Recovery Technologies by Integrating Techno-Economic Analysis and Life-Cycle Assessment.

Methane emissions from worldwide increasing abandoned coal mines have posed multiple challenges of global warming, energy waste, and explosion risk. This study first profiles the dynamic patterns of coal mine methane emissions in different recovery technologies, methane extraction with drainage (MEWD, mine-water concurrently extracted and treated) and direct methane extraction (DME, noncontrol on mine-water), in two abandoned mines from Ningxia and Inner Mongolia as China's leading coal provinces. Then, we conducted a techno-economic analysis and life-cycle assessment to quantify their comprehensive benefits. The key findings are as follows: (1) MEWD can long recover methane, although the economic profits decrease with declining methane extraction volume. DME can only work for ∼5 years, after which the mine is flooded, where methane is sealed underground and not recoverable. (2) MEWD drains and further treats the mine-water with an additional 29.4-35.9 million CNY cost compared with DME, while MEWD can achieve greater life-cycle environmental benefits with more cumulative methane recovery, whose CO2-eq (GWP-100) and SO2 reductions are 64.4 and 53.4% higher than those of DME. (3) MEWD is more promising for large-scale implementation, where feed-in tariffs and carbon market measures can improve the economics for sustainable management of incremental abandoned mine methane.

The toxicity of the monoterpenes from lemongrass is mitigated by the detoxifying symbiosis of bacteria and fungi in the tick Haemaphysalis longicornis.

The entry mode of terpenes into the atmosphere is via volatilization of hydrocarbons from foliage over heavily forested areas besides entering the environment through surface water runoff. Some monoterpenes in essential oils are phytotoxins, acting as plant chemical defenses against bacteria or fungi infections and plant-eating insects. For organisms to survive, their enzymatic systems are activated in response to an assault by potentially harmful compounds. Certain bacterial and fungal genera have developed special abilities to transform toxic terpenes into less toxic derivatives. Here, we investigated the response of the bacterial and fungal community in Haemaphysalis longicornis exposed to Cymbopogon citratus (lemongrass) essential oil (EO) and citronellal. Sequencing of bacterial 16S rRNA and fungal ITS1 regions on an Illumina NovaSeq PE250 sequencing platform was performed for H. longicornis tick samples treated with 15 and 20 mg/mL of lemongrass essential oil and citronellal. The diversity recorded in samples treated with C. citratus EO was higher in comparison to those treated with citronellal but significantly lower in the control samples as reflected by the Shannon diversity index. All major H. longicornis bacterial phyla, including Proteobacteria (93.81 %), Firmicutes (2.58 %), and Bacteroidota (0.99 %) were detected. A switch of dominance from Coxiella to Pseudomonas, which has high biotransformation capacity, was observed in the bacterial community, whereas the phylum Ascomycota (Genera: Aspergillus, Archaeorhizomyces, Alternaria, and Candida) dominated in the fungal community indicating detoxifying symbiosis. Other significantly abundant bacterial genera include Ralstonia, Acinetobacter, Vibrio, and Pseudoalteromonas, while Ganoderma and Trichosporon (yeasts) spp. represented the fungi Basidiomycota. This study expanded the understanding of enzymatic modification of phytotoxic substances by microorganisms, which could provide deeper insights into the mitigation of harmful phytotoxins and the synthesis of eco-friendly derivatives for the control of ticks.

DNA Methylation Variation Is a Possible Mechanism in the Response of Haemaphysalis longicornis to Low-Temperature Stress.

Ticks are notorious ectoparasites and transmit the greatest variety of pathogens than any other arthropods. Cold tolerance is a key determinant of tick abundance and distribution. While studies have shown that DNA methylation is one of the important epigenetic regulations found across many species and plays a significant role in their response to low-temperature stress, its role in the response of ticks to low-temperature stress remains unexplored. Herein, we explored the DNA methylation profile of the tick, Haemaphysalis longicornis, exposed to low-temperature stress (4 °C) using whole-genome bisulfite sequencing (WGBS). We found that approximately 0.95% and 0.94% of the genomic C sites were methylated in the control and low-temperature groups, respectively. Moreover, the methylation level under the CG context was about 3.86% and 3.85% in the control and low-temperature groups, respectively. In addition, a total of 6087 differentially methylated regions (DMRs) were identified between the low-temperature and control groups, including 3288 hypermethylated and 2799 hypomethylated DMRs. Further, Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of differentially methylated genes revealed that most of the DMGs were significantly enriched in binding and RNA transport pathways. Taken together, this research confirmed, for the first time, the whole genome DNA methylation profile of H. longicornis and provided new insights into the DNA methylation changes relating to low-temperature stress in H. longicornis, as well as provided a foundation for future studies on the epigenetic mechanism underlying the responses of ticks to abiotic stress.

Chemical composition of essential oils from Thymus mongolicus, Cinnamomum verum, and Origanum vulgare and their acaricidal effects on Haemaphysalis longicornis (Acari: Ixodidae).

Chemical acaricides are mainly used in traditional tick control, which leads to the emergence of tick resistance and concurrently results in environmental pollution. In the present study, the chemical constituents of essential oils (EOs) from Thymus mongolicus, Cinnamomum verum, and Origanum vulgare was analyzed, and their potential application was evaluated to control the vector tick Haemaphysalis longicornis, which is widely distributed over vast areas of Eurasia, Australia, and New Zealand. Gas chromatography-mass spectrometry analysis revealed that the phenols thymol and carvacrol accounted for 34.66% and 75.72% of the EOs of T. mongolicus and O. vulgare, respectively, whereas trans-cinnamaldehyde (49.42%) was the main constituent of C. verum EO. Immersion tests showed that the EOs of C. verum and O. vulgare had significant acaricidal activity against larval H. longicornis, with the 50% lethal concentration (LC50) being 16.07 and 18.02 mg/mL, respectively, and the 95% lethal concentration (LC95) being 120.37 and 130.09 mg/mL, respectively. The EOs of O. vulgare and T. mongolicus showed significant acaricidal activity against unfed adult H. longicornis, with LC50 being 43.50 and 44.21 mg/mL, respectively, and LC95 being 113.66 and 137.99 mg/mL, respectively. The fumigant toxicity test showed significant acaricidal activity of the three EOs against both unfed and engorged nymphal and adult H. longicornis. Enzyme assays revealed that the EOs of both C. verum and O. vulgare significantly inhibited glutathione S-transferase activity (P < 0.05). In contrast, the activities of carboxylesterase and multifunction oxidases were significantly inhibited by EOs extracted from all three plants (P < 0.05). Taken together, these findings suggest that plant EOs may serve as an environment-friendly alternative for synthetic acaricides in future tick control.

A retrospective review on ixodid tick resistance against synthetic acaricides: implications and perspectives for future resistance prevention and mitigation.

The ending of the nineteenth-century was characterized by an escalation of ticks and tick-borne diseases that resulted in the death of many cattle. This necessitated the search for an effective means of tick control. Arsenicals were introduced in Australia in 1895, and arsenic-based dipping vats went on to be used for about 40 years until resistance was found in ticks and more effective alternatives - chemical acaricides - were developed after World War II. However, the development of resistance by ticks, environmental persistence, and mammalian toxicity militated against the sustained use of subsequent chemical acaricides. Furthermore, the development of resistance is a phenomenon that would always evolve, and the multiple mechanisms underlying the synthetic acaricides resistance are of great importance for future integrated control of ticks and tick-borne diseases. Hence, this study retrospectively reviewed the development of synthetic acaricides and the underlying mechanisms of tick resistance against synthetic acaricides in the hope of providing the implications and perspectives for resistance prevention and mitigation for future tick control.

Transcriptome profile of Haemaphysalis longicornis (Acari: Ixodidae) exposed to Cymbopogon citratus essential oil and citronellal suggest a cytotoxic mode of action involving mitochondrial Ca2+ overload and depolarization.

Haemaphysalis longicornis is an ixodid tick species of medical and veterinary importance. Investigation into the acaricidal activities of botanicals have increased recently but information about their molecular mechanism of action is scarce. Here, RNA-seq analysis of the ticks exposed to Cymbopogon citratus essential oil and citronellal was performed and the responsive genes were identified. More than 6.39 G clean reads with Q20 ≥ 94.88% were obtained for each H. longicornis sample, with an average GC content of 50.94%. Using the Trinity method, 166,710 unigenes with a mean length of 869 bp and a maximum contig length of 29,156 bp were obtained. The upregulation of genes was concentration-dependent in most of the treated groups. Many genes responsive to C. citratus oil and citronellal were stress-related and they include genes associated with adrenergic signaling/calcium channels, cGMP-PKG signaling, apoptosis, focal adhesion, ECM-receptor interaction, ubiquitin-mediated proteolysis, mTOR signaling pathway, and longevity regulating pathway. The upregulation of genes (CACNAID, ADCY9, TPM1, and MYH6) associated with calcium channels suggests a neurotoxic mode of action, whereas, the upregulation of apoptosis-associated genes (CYC, DRONC, CASP7, CASP9, BCL2L1, bcl-xL, etc.) suggests a cytotoxic mode of action. The metabolism of C. citratus essential oil generates oxidative stress which increases the intra-mitochondrial free Ca2+ and triggers the formation of reactive oxygen species (ROS) that culminates to mitochondrial depolarization, ATP depletion, and either necrotic or apoptotic death. The neurotoxic and cytotoxic effects exhibited by the monoterpenes in H. longicornis is vital and could be exploited for the advancement of acaricide development and eco-friendly tick control.

A novel defensin-like peptide contributing to antimicrobial and antioxidant capacity of the tick Dermacentor silvarum (Acari: Ixodidae).

Defensins are the most diverse groups of antimicrobial peptides in invertebrate animals. In ticks, defensins show great potential as targets for tick control, and display future prospect for therapeutic drug development. In the present study, a novel defensin-like gene (Ds-defensin) contributing to the antimicrobial and antioxidant capacity of the tick Dermacentor silvarum was characterized. The full-length of the Ds-defensin gene was 382 bp, which displayed tissue-specific expression and was highly abundant in the salivary glands and carcasses of the adults. It encodes a 71-amino acid defensin-like protein, and the protein precursor is characterized by a 22-amino acid signal peptide and a 34-amino acid mature peptide. The peptide displayed potent activity against most of the tested gram-positive bacteria, including Staphylococcus aureus, S. carnosus and Nocardia asteroides, and one tested gram-negative bacterium, Psychrobacter faecalis. Scanning electron microscopy revealed that the cell wall and surface of treated bacteria became rough and gradually formed pores after a 30-min exposure to the Ds-defensin peptide. Additionally, the peptide also showed significant antioxidant capacity. The above results implied that the defensin-like peptide may play an important role in tick defense and the interaction with microorganisms.

Precise annotation of tick mitochondrial genomes reveals multiple copy number variation of short tandem repeats and one transposon-like element.

BACKGROUND: In the present study, we used long-PCR amplification coupled with Next-Generation Sequencing (NGS) to obtain complete mitochondrial (mt) genomes of individual ticks and unprecedently performed precise annotation of these mt genomes. We aimed to: (1) develop a simple, cost-effective and accurate method for the study of extremely high AT-content mt genomes within an individual animal (e.g. Dermacentor silvarum) containing miniscule DNA; (2) provide a high-quality reference genome for D. silvarum with precise annotation and also for future studies of other tick mt genomes; and (3) detect and analyze mt DNA variation within an individual tick. RESULTS: These annotations were confirmed by the PacBio full-length transcriptome data to cover both entire strands of the mitochondrial genomes without any gaps or overlaps. Moreover, two new and important findings were reported for the first time, contributing fundamental knowledge to mt biology. The first was the discovery of a transposon-like element that may eventually reveal much about mechanisms of gene rearrangements in mt genomes. Another finding was that Copy Number Variation (CNV) of Short Tandem Repeats (STRs) account for mitochondrial sequence diversity (heterogeneity) within an individual tick, insect, mouse or human, whereas SNPs were not detected. The CNV of STRs in the protein-coding genes resulted in frameshift mutations in the proteins, which can cause deleterious effects. Mitochondria containing these deleterious STR mutations accumulate in cells and can produce deleterious proteins. CONCLUSIONS: We proposed that the accumulation of CNV of STRs in mitochondria may cause aging or diseases. Future tests of the CNV of STRs hypothesis help to ultimately reveal the genetic basis of mitochondrial DNA variation and its consequences (e.g., aging and diseases) in animals. Our study will lead to the reconsideration of the importance of STRs and a unified study of CNV of STRs with longer and shorter repeat units (particularly polynucleotides) in both nuclear and mt genomes.

Community structure and diversity of the microbiomes of two microhabitats at the root-soil interface: implications of meta-analysis of the root-zone soil and root endosphere microbial communities in Xiong'an New Area.

The diversity of the microbial compositions of the root-zone soil (the rhizosphere-surrounding soil) and root endosphere (all inner root tissues) of Pinus tabulaeformis Carr. and Ginkgo biloba L. were evaluated in Xiong'an New Area using high-throughput sequencing; the influence of the soil edaphic parameters on microbial community compositions was also evaluated. Our results showed that both the taxonomic and phylogenetic diversities of the root endosphere were lower than those of the root-zone soil, but the variation in the endosphere microbial community structure was remarkably higher than that of the root-zone soil. Spearman correlation analysis showed that the soil organic matter, total nitrogen, total phosphate, total potassium, ratio of carbon to nitrogen, and pH significantly explained the α-diversity of the bacterial community and that total nitrogen differentially contributed to the α-diversity of the fungal community. Variation partitioning analysis showed that plant species had a greater influence on microbial composition variations than did any other soil property, although soil chemical parameters explained more variation when integrated. Together, our results suggest that both plant species and soil chemical parameters played a critical role in shaping the microbial community composition.

Effects of the essential oil from Cymbopogon citratus on mortality and morphology of the tick Haemaphysalis longicornis (Acari: Ixodidae).

Haemaphysalis longicornis is one of the most prevalent tick species across eastern Asia, Australia, and New Zealand, and has been implicated as a vector of several pathogenic agents. This study evaluated the in vitro acaricidal efficacy of Cymbopogon citratus (lemongrass) essential oil on unfed H. longicornis using the adult and nymph immersion test, and the larval packet test. Six concentrations with three replications each of 10, 20, 30, 40, 50 and 60 mg/mL (adults and nymphs) were used, and 2.5, 5, 10, 20, 40 and 80 mg/mL (larvae), with control group (50% ethanol). The adult and nymph mortality rates were 98 and 100% at 50 mg/mL, and 95 and 100% at 60 mg/mL, respectively, whereas the larval mortality rate was 94 and 96% at 40 and 80 mg/mL, respectively. Mortality of adult, nymph and larva increased significantly in a dose-dependent manner. The LC50 for adult, nymph, and larva, were 29.21 (95% confidence interval 25.90-32.58), 28.18 (23.78-32.25), and 28.06 (25.57-30.90) mg/mL, respectively. Scanning electron microscopy and light microscopy revealed a disjointed sensilla base from the sockets, cuticular cracks, blocked aeropyles, and shrinking of the midgut. These results showed that C. citratus essential oil could be a good eco-friendly alternative control strategy against ectoparasites like ticks due to its high acaricidal efficacy.

Botanical acaricides and repellents in tick control: current status and future directions.

Ticks are obligate blood-sucking ectoparasites and notorious as vectors of a great diversity of, in many instances, zoonotic pathogens which can cause considerable damage to animal and human health. The most commonly used approach for the control of ticks is the application of synthetic acaricides. However, the negative impacts of synthetic acaricides on the treated animals and the environment, in addition to its documented role in the development of resistance has led to the search for safer and more environmentally friendly alternative methods without compromising efficacy. An emerging promising approach for the control of ticks which has attracted much attention in recent years is the use of botanicals. Indeed, botanicals have been widely reported to show diverse effects and great potential as tick repellent and control. Although several excellent reviews have previously focused on this topic, studies on the exploration and application of botanicals to control ticks have expanded rapidly. Herein, we provide an update on the current understanding and status of botanical acaricides and repellents in tick control using recently published articles between 2017 and 2019. We also discuss the challenges and future directions in the application of botanicals in tick control, with a view of providing important clues for designing new integrated tick control methods.

Seasonal abundance and activity of the tick Dermacentor everestianus (Acari: Ixodidae) in the Tibetan Plateau, China.

Dermacentor everestianus is an important vector for several pathogens endemic in the Qinghai-Tibet Plateau. However, knowledge of its seasonal activity and abundance is limited. Hence, the seasonal dynamics of questing and host-feeding D. everestianus were investigated from March 2014 to February 2016 in Damxung County, north of Lhasa City in Tibet. During the 2-year period, questing ticks were collected weekly from two habitats (grassland and shrubs) by flag-dragging. Host-feeding ticks were removed weekly from sheep and their attachment sites were recorded. Plateau pikas (Ochotona curzoniae) captured by traps were examined for immature ticks from May to September 2014. Results revealed that questing D. everestianus were primarily distributed in grassland, whereas host-feeding adults and nymphs were mainly found on sheep, and larvae usually were on plateau pikas. Dermacentor everestianus can complete one generation per year with population overlap between the larvae and nymphs. Adults were mainly observed from February to April with the major peak occurring in late March. Additionally, unfed adults were detected on sheep from August to next February. Nymphs were found from late May to July and reached their peak in late June. Larvae collected during May and June reached peak numbers in late May.

PB2 and hemagglutinin mutations confer a virulent phenotype on an H1N2 avian influenza virus in mice.

We previously obtained mouse-adapted variants of H1N2 avian influenza virus that contained PB2-L134H, PB2-I647L, PB2-D701N, HA-G228S, and M1-D231N mutations. Here, we analyzed the effects of these mutations on viral pathogenicity in a mammalian model. By evaluating the virulence of mouse-adapted H1N2 variants at different generations, we found that the PB2-D701N and HA-G228S mutations both contribute to the virulence of this virus in mammals. Furthermore, we found that the PB2-D701N and HA-G228S mutations both enhance the ability of the virus to replicate in vivo and in vitro and that the PB2-D701N substitution results in an expansion of viral tissue tropism. These results suggest that the PB2-D701N mutation and the HA-G228S mutation are the major mammalian determinants of H1N2 virus. These results help us to understand more about the mechanisms by which influenza viruses adapt to mammals, and monitoring of these mutations can be used in continuous influenza surveillance to assess the pandemic potential of avian influenza virus variants.

Enzymatic and Biological Characterization of Novel Sirtuin Modulators against Cancer.

Sirtuins, a family of nicotinamide adenine dinucleotide (NAD+)-dependent lysine deacetylases, are promising targets for anticancer treatment. Recently, we characterized a novel pan-sirtuin (SIRT) inhibitor, MC2494, displaying antiproliferative effects and able to induce death pathways in several human cancer cell lines and decrease tumor growth in vivo. Based on the chemical scaffold of MC2494, and by applying a structure-activity relationship approach, we developed a small library of derivative compounds and extensively analyzed their enzymatic action at cellular level as well as their ability to induce cell death. We also investigated the effect of MC2494 on regulation of cell cycle progression in different cancer cell lines. Our investigations indicated that chemical substitutions applied to MC2494 scaffold did not confer higher efficacy in terms of biological activity and SIRT1 inhibition, but carbethoxy-containing derivatives showed higher SIRT2 specificity. The carbethoxy derivative of MC2494 and its 2-methyl analog displayed the strongest enzymatic activity. Applied chemical modifications improved the enzymatic selectivity of these SIRT inhibitors. Additionally, the observed activity of MC2494 via cell cycle and apoptotic regulation and inhibition of cell migration supports the potential role of SIRTs as targets in tumorigenesis and makes SIRT-targeting molecules good candidates for novel pharmacological approaches in personalized medicine.

The mitochondrial genome of the ornate sheep tick, Dermacentor marginatus.

The ornate sheep tick, Dermacentor marginatus, is widespread in Europe. Its vector role of various zoonotic pathogens received much attention in these regions. However, the genomic resources of the ticks are limited. In this study, the complete mitochondrial genome of a single female D. marginatus collected in Slovakia was sequenced through the Illumina HiSeq sequencing platform. The mitochondrial genome is 15,067 bp long and contains 13 protein-coding genes, two ribosomal RNA genes and 22 transfer RNA genes. The overall G+C content is 21.6%. The gene order is identical to that of Metastriata ticks. The codon usage pattern is similar with that of other tick species. As in other ticks, two truncated tRNA genes were observed. Two control regions were found between tRNA-Leu and tRNA-Cys, tRNA-Ile and rrnS, respectively. The mitochondrial genome contains three noncoding regions, which is similar to that in D. nitens. The noncoding region located between rrnS and tRNA-Val is shorter than that of other Dermacentor species. Phylogenetic analyses indicate that D. marginatus is clustered with other Dermacentor species. These findings are helpful for exploring the systematics and evolution of ticks in the future.