E1 E2 Research Articles

Optical properties and the electronic structure of Co2TiGe and Co2TiSn Heusler alloys

The frequency dependences of the real part e1(ω) and imaginary part e2(ω) of the complex dielectric constant of the Heusler alloys Co2TiGe and Co2TiSn have been studied in the spectral range of 0.1–5 eV. It has been established that the interband electron transitions play a dominant role in the formation of the optical properties of these alloys. An anomalous behavior of the optical properties in the IR range of spectrum, namely, the absence of the Drude component of the optical conductivity σ(ω), has been revealed. The results of the studies have been discussed based on the calculations of the electronic structure of the alloys.

Apontic directly activates hedgehog and cyclin E for proper organ growth and patterning

Hedgehog (Hh) signaling pathway and Cyclin E are key players in cell proliferation and organ development. Hyperactivation of hh and cyclin E has been linked to several types of cancer. However, coordination of the expression of hh and cyclin E was not well understood. Here we show that an evolutionarily conserved transcription factor Apontic (Apt) directly activates hh and cyclin E through its binding site in the promoter regions of hh and cyclin E. This Apt-dependent proper expression of hh and cyclin E is required for cell proliferation and development of the Drosophila wing. Furthermore, Fibrinogen silencer-binding protein (FSBP), a mammalian homolog of Apt, also positively regulates Sonic hh (Shh), Desert hh (Dhh), Cyclin E1 (CCNE1) and Cyclin E2 (CCNE2) in cultured human cells, suggesting evolutionary conservation of the mechanism. Apt-mediated expression of hh and cyclin E can direct proliferation of Hh-expressing cells and simultaneous growth, patterning and differentiation of Hh-recipient cells. The discovery of the simultaneous expression of Hh and principal cell-cycle regulator Cyclin E by Apt implicates insight into the mechanism by which deregulated hh and cyclin E promotes tumor formation.

MLN4924 (Pevonedistat), a protein neddylation inhibitor, suppresses proliferation and migration of human clear cell renal cell carcinoma

Neddylation is a post-translational protein modification associated with cancer development. MLN4924 is a neddylation inhibitor currently under investigation in multiple phase I studies on various malignancies, and its clincal name is Pevonedistat. It has been documented that MLN4924 blocks Cullins neddylation and inactivates CRLs and, in turn, triggers cell-cycle arrest, apoptosis, senescence and autophagy in many cancer cells. In this study, we investigated the anti-tumor effect of MLN4924 in human clear cell renal carcinoma (ccRCC). Levels of both Nedd8 activating enzyme E1 and Nedd8-conjugating enzyme E2 were higher in ccRCC tissues and RCC cancer cells than in normal. Moreover, MLN4924 treatment led to rapid inhibition of Cullin1 neddylation and notably suppressed growth and survival as well as migration in a dose-and time-dependent manner. Mechanistic studies revealed that MLN4924 induced the accumulation of a number of CRL substrates, including p21, p27 and Wee1 to trigger DNA damage and induce growth arrest at the G2/M phase. MLN4924 also induced anti-migration and anti-invasion by activating E-cadherin and repressing Vimentin. Taken together, this study provides the first evidence that neddylation pathway is overactive in ccRCC and that MLN4924 induces dose-dependent anti-proliferation, anti-migration, anti-invasion in ccRCC cells. The study thus indicates that MLN4924 has potential therapeutic value for the clinical treatment of renal cancer.

The role of prostaglandins E1 and E2, dinoprostone, and misoprostol in cervical ripening and the induction of labor: a mechanistic approach.

Prostaglandins play a critical role in cervical ripening by increasing inflammatory mediators in the cervix and inducing cervical remodeling. Prostaglandin E1 (PGE1) and prostaglandin E2 (PGE2) exert different effects on these processes and on myometrial contractility. These mechanistic differences may affect outcomes in women treated with dinoprostone, a formulation identical to endogenous PGE2, compared with misoprostol, a PGE1 analog. The objective of this review is to evaluate existing evidence regarding mechanistic differences between PGE1 and PGE2, and consider the clinical implications of these differences in patients requiring cervical ripening for labor induction. We conducted a critical narrative review of peer-reviewed articles identified using PubMed and other online databases. While both dinoprostone and misoprostol are effective in cervical ripening and labor induction, they differ in their clinical and pharmacological profiles. PGE2 has been shown to stimulate interleukin-8, an inflammatory cytokine that promotes the influx of neutrophils and induces remodeling of the cervical extracellular matrix, and to induce functional progesterone withdrawal. Misoprostol has been shown to elicit a dose-dependent effect on myometrial contractility, which may affect rates of uterine tachysystole in clinical practice. Differences in the mechanism of action between misoprostol and PGE2 may contribute to their variable effects in the cervix and myometrium, and should be considered to optimize outcomes.

Identification of a new small ubiquitin-like modifier (SUMO)-interacting motif in the E3 ligase PIASy

Small ubiquitin-like modifier (SUMO) conjugation is a reversible post-translational modification process implicated in the regulation of gene transcription, DNA repair, and cell cycle. SUMOylation depends on the sequential activities of E1 activating, E2 conjugating, and E3 ligating enzymes. SUMO E3 ligases enhance transfer of SUMO from the charged E2 enzyme to the substrate. We have previously identified PIASy, a member of the Siz/protein inhibitor of activated STAT (PIAS) RING family of SUMO E3 ligases, as essential for mitotic chromosomal SUMOylation in frog egg extracts and demonstrated that it can mediate effective SUMOylation. To address how PIASy catalyzes SUMOylation, we examined various truncations of PIASy for their ability to mediate SUMOylation. Using NMR chemical shift mapping and mutagenesis, we identified a new SUMO-interacting motif (SIM) in PIASy. The new SIM and the currently known SIM are both located at the C terminus of PIASy, and both are required for the full ligase activity of PIASy. Our results provide novel insights into the mechanism of PIASy-mediated SUMOylation. PIASy adds to the growing list of SUMO E3 ligases containing multiple SIMs that play important roles in the E3 ligase activity.

Application of Dosage Combinations of Evagrow Biofertilizer and Chemical Fertilizer on Soil Characteristics, Growth and Yield of Rice

Research on the effect of dosage combination of Evagrow bio-fertilizer and chemical fertilizers on soil properties, growth and yield of rice has been carried out in the glasshouse, Faculty of Agriculture, Udayana University using factorial experiment with a Randomized Block Design (RBD). The first factor is Evagrow bio-fertilizer in 3 level, i.e. E0 (without bio-fertilizers), E1 (5 g bio-fertilizer/L) E2 (10 grams bio-fertilizer/L). The second factor is chemical fertilizer, which consists of 3 levels: K0 (without chemical fertilizers), K1 (150 kg Urea/ha + 75 kg SP36/ha + 37.5 kg KCl/ha), K2 (300 kg Urea/ha + 150 kg SP36/ha + 75 kg KCl/ha). The results showed that chemical fertilizers give a significant and very significant effect on most of the rice growth and yield parameters. The application of chemical fertilizers K1 and K2 increased yield of dry grain harvest to 52.87% and 102.54% compared to controls. Application of Evagrow bio-fertilizer did not significantly increase growth and yield of rice. There is no interaction between chemical fertilizers and Evagrow bio- fertilizer. Similarly to some of the soil characteristics, biological fertilizer and chemical fertilizer application did not show significant effect on most of the soil characteristics, except on salt levels.Keywords: Evagrow Biofertilizer, Inorganic Fertilizer, Oryza Sativa

IN SILICO STUDY OF CRYO-EM STRUCTURES OF ANTIGEN-ANTIBODY COMPLEX OF CHIKUNGUNYA FOR THE DEVELOPMENT OF DIAGNOSTIC AGENT

Objective: Despite the availability of the commercial rapid tests of chikungunya, the difference of pathogen’s genotypes amongst different countries has created some causes for concern. It is found that the sensitivity of the current chikungunya rapid tests on Asian strain was only 20.5%, as compared to 90.3% when tested on the African phylogroup. Therefore, the development of diagnostics that is specific for the current strain circulating in the country is important to be done. The cryo-electron microscopy (cryo-EM) structures of antigen-antibody complex can be used as an insightful structural basis to the development of the tailored antibody for diagnostics purposes. However, cryo-EM structures usually were resolved in low resolution, thus some sterical clashes between residues are expected. This work aims to refine the cryo-EM structures of E1 E2 of chikungunya virus (CHIKV) in complex with antibody using molecular mechanics method, to calculate the binding energy of antigen-antibody complex, and to compare it with the experimental results.Methods: Thecryo-EM structures were refined in vacuoby short minimization scheme using AMBER 14. The binding energies were calculated using Firedock and MM/GBSA methods.Results:The results showed that the direct calculation of binding energies of cryo-EM structures reflected high repulsive forces. While the calculation on the refined structured showed lower binding energies. Visual inspections on the complex structures also indicated that the refined structures showed better interactions.Conclusion:As a conclusion, the refinement of cryo-EM structures should be useful to gain more insight into the binding mode of interactions between antigenic protein and antibody, at the atomic level.

Design of peptide inhibitors of human papillomavirus 16 (HPV16) transcriptional regulator E1–E2 formation

Here, we have proposed a new scheme of the computational combinatorial design approach to identify potential inhibitor peptides. It consists of four steps: (i) using “multiple copy simultaneous search” (MCSS) procedure to locate specific functional groups on the protein surface; (ii) the peptide main chain is constructed based on the location of favored N-methylacetamide (NMA) groups; (iii) molecular dynamics simulations of the complex formed between the constructed peptides with the target protein in explicit water molecules are carried to select the peptides with strong binding to the protein and (iv) the sequences of the stable peptides selected from (iii) are aligned and the frequencies of the amino acids at each position of peptide are calculated. Sequence patterns of potential inhibitors are determined based on the frequency of amino acids at each position. It was applied to design peptide inhibitors that bind to the E2 protein of HPV16 so as to disrupt its transcriptional regulator of E1–E2 complex formation. The sequence pattern of these potential inhibitors is in agreement with known inhibitors obtained from phage display, and the MCSS calculations indicate that a hydrophobic pocket on HPV16 E2 plays a significant role in E1–E2 formation and inhibitor-E2 binding.

국제 육상투척 경기대회 여자 원반던지기 선수들의 투사거리에 미치는 운동학적 분석

This research aims to recommend desirable performance enhancement training methods for discus throw to instructors. To accomplish this, we analyzed parameters that may affect the kinematic element of techniques and projection distances of throws by female discus throwers who participated in Mokpo International Athletics Throwing Meeting. We additionally aim to provide scientific baseline data in training process, based on quantitative results. The conclusions are as follows. Based on thee lapsed times per sector, player Insceng was the fastest with 1.167 sec, while player Jungyerim was the slowest with 1.750 sec. In terms of the vertical displacement of the center of the gravity in each situation, player Insceng produced the highest vertical displacemen t increase of 4.49 cm, in sector 1 (E1–E2), compared to the other Korean players, while producing the smallest increase of 5.57 cm, in sector 4 (E4–E5). Insceng from Taiwan produced the highest discus projection height of 146 cm and the highest speed of 38.21 m/sec. at the point of discus release. In terms of twist angles of the body, Insceng produced the smallest angles of 144.08° and -80.55° at points E1 and E4, respectively, while displaying the smallest front and rear inclination angles of 7.149°, 60.36°, and 53.76° at points E2, E3, and E4 , respectively. There was a little difference in the horizontal, front, and rear trajectories of the discuses between player Insceng and the Korean players.

Regulating the Master Regulator: Controlling Ubiquitination by Thinking Outside the Active Site.

The labeling of proteins with ubiquitin/ubiquitin-like (Ubl) proteins is crucial for several physiological processes and in the onset of various diseases. Recently, targeting ubiquitin protein labeling has shifted toward the use of allosteric mechanisms over classical activity-based approaches. Allosteric enzyme regulation offers the potential for greater selectivity and has demonstrated less susceptibility to acquired resistance often associated with active site inhibitors. Furthermore, the isoform diversity among E1 activating, E2 conjugating, E3 ligase, and deubiquitinating (DUB) enzymes offers an ideal platform for modulating activity via allostery. Herein, we have reviewed allosteric inhibitors of the ubiquitin E1-E2-E3 and DUB enzymatic cascade developed over the past decade with a focus on their mechanisms of action. We have highlighted the advantages as well as the challenges associated with designing allosteric modulators of the ubiquitin labeling machinery, and the future promise in targeting these systems using allosteric approaches.

Structural, electronic and optical properties of CsPbX3 (X=Cl, Br, I) for energy storage and hybrid solar cell applications

Abstract Organic-Inorganic perovskites CsPbX3 (X = Cl, Br, I) are investigated for their potential ability and use as solar cells and energy storage materials, using density function theory, generalized gradient approximation and modified Becke-Johnson (TB-mBJ) exchange potential. Structural analysis shows that the lattice constant and unit cell volume varies when CsPbX3 (X = Cl, Br, I) change from cubic phase to tetragonal and orthorhombic structures. The electronic properties show that CsPbCl3, CsPbBr3 and CsPbI3 all are semiconductor in with bandgap between 0.79 eV and 2.54 eV. It is also observed that the bandgap changes when the structure changes. Optical properties show that these materials have a good absorption ability of photons due to their narrow bandgaps. The real e1(ω) and imaginary e2(ω) parts of their dielectric functions show that CsPbCl3, CsPbBr3 and CsPbI3 also possess a great ability of retaining the energy it absorbs. These properties make them very suitable for solar cells and energy storage applications. These materials also behave as superluminescent material at high photon energy.

Structural analysis and evolution of specificity of the SUMO UFD E1-E2 interactions

SUMO belongs to the ubiquitin-like family (UbL) of protein modifiers. SUMO is conserved among eukaryotes and is essential for the regulation of processes such as DNA damage repair, transcription, DNA replication and mitosis. UbL modification of proteins occurs via a specific enzymatic cascade formed by the crosstalk between the E1-activating enzyme, the E2-conjugating enzyme and the E3-ligase. An essential discrimination step in all UbL modifiers corresponds to the interaction between E1 and E2 enzymes, which is mediated by the recruitment of the E2 to the UFD domain (Ubiquitin-Fold Domain) of the E1 enzyme. To gain insights in the properties of this interface, we have compared the structures of the complexes between E1 UFD domain and E2 in human and yeast, revealing two alternative UFD platforms that interact with a conserved E2. Comparative sequence analysis of the E1 UFD domain indicates that the E2 binding region has been conserved across phylogenetic closely related species, in which higher sequence conservation can be found in the E2 binding region than in the entire UFD domain. These distinctive strategies for E1-E2 interactions through the UFD domain might be the consequence of a high selective pressure to ensure specificity of each modifier conjugation system.

Haematological indicators in hybrid mallard ducks (Anas platyrhynchos) with regard to the use of meal from whole white lupin seeds in their diet

The objective of our study was to assess the effect of replacing soybean meal with the meal from whole white lupin seeds (Lupinus albus) of the Zulika variety in diets on selected haematological indicators in 40-day-old fattened hybrid mallard ducks. A total of 180 Cherry Valley ducks were divided into three groups (E1, E2, and control). The control group was fed a diet containing soybean meal. Soybean meal replaced with 50% and 100% meal of white lupin seeds were used in group E1 and group E2, respectively. At the end of the fattening, 12 ducks (6 males and 6 females) were randomly selected from each group for a haematological examination. From the result of this study, it is clear that the effect of the diet was found only on the slightly varying number of white blood cells and on the proportion of monocytes. Ducks of group E2 showed a slight increase in the total number of leukocytes which was accompanied by a decrease in the percentage share of monocytes (P< 0.05). Based on the results, it can be claimed that the replacement of soybean meal with meal from the Zulika variety of whole white lupin seeds in the diet did not have a negative effect on the determined blood indicators. Therefore, whole white lupin seeds were successfully used as the important protein component of the diet for fattening hybrid mallard ducks.

AC conductivity and dielectric relaxation of bulk tris (8-hydroxyquinoline) aluminum organic semiconductor

The frequency dependent conductivity and dielectric behavior of bulk tris (8-hydroxyquinoline) aluminium(III) (Alq3) have been studied in the temperature range (293–473 K) and frequency range (102–5 MHz). The AC conductivity, σac, was found to be proportional to ωs (where ω is the angular frequency). The exponent frequencies was found to be less than unity and decreased by increasing temperature. This behavior suggests that the correlated barrier hopping (CBH) model is the most predominated conduction mechanism. Both the dielectric constant e1 (ω) and dielectric loss e2 (ω) are decreased with the increase of frequency while they are increased with the increase of temperature in the investigated ranges. The complex diagram of electric modulus gives an evidence of existence of the type of Debye relaxation. The relaxation time (τ) and activation energy for relaxation (Ea) were determined.

Construction of regular rate-compatible LDPC convolutional codes

In this paper, we propose a new method to derive a family of regular rate-compatible low-density parity-check (RC-LDPC) convolutional codes from RC-LDPC block codes. In the RC-LDPC convolutional family, each extended sub-matrix of each extended code is obtained by choosing specified elements from two fixed matrices Hk E1 and Hk E2 , which are derived by modifying the extended matrices H E1 and H E2 of a systematic RC-LDPC block code. The proposed method which is based on graph extension simplifies the design, and prevent the defects caused by the puncturing method. It can be used to generate both regular and irregular RC-LDPC convolutional codes. All resulted codes in the family are systematic which simplify the encoder structure and have maximum encoding memories which ensure the property. Simulation results show the family collectively offer a steady improvement in performance with code compatibility over binary-input additive white Gaussian noise channel (BI-AW-GNC).

A cascading activity-based probe sequentially targets E1-E2-E3 ubiquitin enzymes.

Post-translational modifications of proteins with ubiquitin (Ub) and ubiquitin-like modifiers (Ubls), orchestrated by a cascade of specialized E1, E2 and E3 enzymes, control a wide range of cellular processes. To monitor catalysis along these complex reaction pathways, we developed a cascading activity-based probe, UbDha. Similarly to the native Ub, upon ATP-dependent activation by the E1, UbDha can travel downstream to the E2 (and subsequently E3) enzymes through sequential trans-thioesterifications. Unlike the native Ub, at each step along the cascade, UbDha has the option to react irreversibly with active site cysteine residues of target enzymes, thus enabling their detection. We show that our cascading probe 'hops' and 'traps' catalytically active Ub-modifying enzymes (but not their substrates) by a mechanism diversifiable to Ubls. Our founder methodology, amenable to structural studies, proteome-wide profiling and monitoring of enzymatic activity in living cells, presents novel and versatile tools to interrogate Ub and Ubl cascades.

A novel ubiquitin-protein ligase E3 functions as a modulator of immune response against lipopolysaccharide in Pacific oyster, Crassostrea gigas

Ubiquitination is an important post-translational protein modification and plays a crucial role in various processes such as cell cycle, signal transduction, and transcriptional regulation. In the present study, a novel ubiquitin (Ub)-protein ligase E3 (designed as CgE3Rv1) was identified from Crassostrea gigas, and its ubiquitination regulation in the immune response against lipopolysaccharide (LPS) stimulation was investigated. The open reading frame of CgE3Rv1 gene was of 1455 bp encoding a polypeptide of 484 amino acids with the predicted molecular mass of 54.89 kDa. There were two transmembrane regions and a RING-variant (RINGv) domain identified in CgE3Rv1. CgE3Rv1 shared similar C4HC3 zinc-finger-like motif with those RINGv domain Ub-protein ligases E3s identified from vertebrates and invertebrates, and it was closely clustered with the membrane-associated RING-CH2 (MARCH2) Ub-protein ligases E3s in the phylogenetic tree. The mRNA transcript of CgE3Rv1 was highest expressed in gonads and hemolymph (p < 0.05), and its mRNA expression level in hemocytes was significantly increased at 6 h (p < 0.01) after the stimulation of LPS, while the up-regulated mRNA expression was significantly decreased (p < 0.01) after acetylcholine stimulation. No significant changes of CgE3Rv1 expression were observed after peptidoglycan or mannan stimulation. Immunohistochemistry and in situ hybridization assays revealed that CgE3Rv1 protein and mRNA were dominantly distributed in the gonad. In the hemocytes, CgE3Rv1 was mainly located around the nucleus, and slightly distributed in the cytoplasm and on the cell membrane. Recombinant CgE3Rv1 RINGv domain protein (rCgE3Rv1-RINGv) was confirmed to activate the Ub reaction system in vitro with the aid of Ub-activating enzyme E1 and Ub-conjugating enzyme E2. These results demonstrated that CgE3Rv1 was an Ub-protein ligase E3, which was involved in the immune response against LPS and the interaction with cell surface signal molecules of neuroendocrine-immune system in oysters.

UbiSite: incorporating two-layered machine learning method with substrate motifs to predict ubiquitin-conjugation site on lysines

BackgroundThe conjugation of ubiquitin to a substrate protein (protein ubiquitylation), which involves a sequential process – E1 activation, E2 conjugation and E3 ligation, is crucial to the regulation of protein function and activity in eukaryotes. This ubiquitin-conjugation process typically binds the last amino acid of ubiquitin (glycine 76) to a lysine residue of a target protein. The high-throughput of mass spectrometry-based proteomics has stimulated a large-scale identification of ubiquitin-conjugated peptides. Hence, a new web resource, UbiSite, was developed to identify ubiquitin-conjugation site on lysines based on large-scale proteome dataset.ResultsGiven a total of 37,647 ubiquitin-conjugated proteins, including 128026 ubiquitylated peptides, obtained from various resources, this study carries out a large-scale investigation on ubiquitin-conjugation sites based on sequenced and structural characteristics. A TwoSampleLogo reveals that a significant depletion of histidine (H), arginine (R) and cysteine (C) residues around ubiquitylation sites may impact the conjugation of ubiquitins in closed three-dimensional environments. Based on the large-scale ubiquitylation dataset, a motif discovery tool, MDDLogo, has been adopted to characterize the potential substrate motifs for ubiquitin conjugation. Not only are single features such as amino acid composition (AAC), positional weighted matrix (PWM), position-specific scoring matrix (PSSM) and solvent-accessible surface area (SASA) considered, but also the effectiveness of incorporating MDDLogo-identified substrate motifs into a two-layered prediction model is taken into account. Evaluation by five-fold cross-validation showed that PSSM is the best feature in discriminating between ubiquitylation and non-ubiquitylation sites, based on support vector machine (SVM). Additionally, the two-layered SVM model integrating MDDLogo-identified substrate motifs could obtain a promising accuracy and the Matthews Correlation Coefficient (MCC) at 81.06 % and 0.586, respectively. Furthermore, the independent testing showed that the two-layered SVM model could outperform other prediction tools, reaching at 85.10 % sensitivity, 69.69 % specificity, 73.69 % accuracy and the 0.483 of MCC value.ConclusionThe independent testing result indicated the effectiveness of incorporating MDDLogo-identified motifs into the prediction of ubiquitylation sites. In order to provide meaningful assistance to researchers interested in large-scale ubiquitinome data, the two-layered SVM model has been implemented onto a web-based system (UbiSite), which is freely available at http://csb.cse.yzu.edu.tw/UbiSite/. Two cases given in the UbiSite provide a demonstration of effective identification of ubiquitylation sites with reference to substrate motifs.Electronic supplementary materialThe online version of this article (doi:10.1186/s12918-015-0246-z) contains supplementary material, which is available to authorized users.

Genetic diversity revealed by Morphological Descriptors Among Yellow Sarson Germplasm Under Timely and Late Sown Conditions

Thirty-one local germplasm lines of Brassica rapa var. yellow sarson, collected from eastern parts of Uttar Pradesh (India) were evaluated along with two commercial varieties as checks in two environmental conditions (timely sown E1 and late sown E2 conditions). Data collected on 14 morphological characters was subjected to D2 statistics. The 31 germplasm lines were classified into 8 and 12 clusters under E1 and E2, respectively. In E1, cluster I had a maximum of 15 genotypes while cluster III, VII and VIII had only one genotype each, in E2, cluster III had maximum of 15 genotypes whereas cluster IV, V, VII, VIII, X, XI, and XII had only one genotype each. Likewise, the inter-cluster average D2value was maximum (26.81) between cluster III and VIII and minimum between cluster V and I (2.80). Intra-cluster average D2 values ranged from 0.00 to 4.63. In late sown condition, the inter-cluster distance was maximum between IV and II (51.93) and minimum in cluster VI and IX (4.965). Intra-cluster average D2 value ranged from 0.0 to 4.594. The genotypes which occupied distant clusters can be used in hybridization programme as parents to recover more heterotic hybrids. Secondary branchesplant−1, glucosinolatecontent, seed yield, seeds siliqua−1, primary branches plant−1 and siliqua length contributed maximum towards total divergence in timely sown condition whereas secondary branches plant−1, seed yield, primary branches plant−1, glucosinolate content, and main raceme length were the major contributors in late sown conditions.

Proteomic analysis of Bayvarol® resistance mechanisms in the honey bee parasite Varroa destructor

The haemophagous mite, Varroa destuctor is one of the most dangerous threats to the Western honey bee, Apis mellifera. Varroa mites parasitize the larval and adult stages of the honey bee and can have devastating effects on the health of the individual bee and colony. In recent years, varroa have shown resistance to the pyrethroid group of insecticides, including Bayvarol® which has flumethrin as the active ingredient. In the work presented here, changes in the expressed proteomes of mites, either sensitive or resistant to Bayvarol® were observed using 2D-SDS-PAGE and shotgun label-free proteomics. A number of detoxification proteins (e.g., glutathione-s-transferase, flavin-containing monooxygenase) were present at higher levels in the resistant mites, as were some proton pumping proteins (e.g., Na+/K+ ATPase alpha and beta subunit, E1–E2 ATPase protein). A decrease in the abundance of 12 cuticle proteins in the resistant mites was observed indicating that alteration to cuticle structure could be a potential resistance mechanism. A number of structural proteins such as myosin and alpha tubulin were expressed at higher levels in the resistant mites, which could indicate a change to the intracellular structure of the cuticle barrier or a change in the cell shape/surface, rather than the addition of extra cuticle proteins. The results presented here indicate higher levels of protein associated with cellular detoxification in Bayvarol®-resistant varroa mites.