Genotoxic Potential of Thymol on Honey Bee DNA in the Comet Assay

Thymol is a natural essential oil derived from the plant Thymus vulgaris L. It is known to be beneficial for human and animal health and has been used in beekeeping practice against Varroa mite for years. In this study, the genotoxic and antigenotoxic potential of thymol were evaluated on the honey bee (Apis mellifera L.) continuous cell line AmE-711 for the first time. Using the Comet assay, three increasing concentrations (10, 100, and 1000 µg/mL) of thymol were tested. Negative control (non-treated cells) and positive control (cells treated with 100 µM H₂O₂) were also included. The absence of thymol cytotoxicity was confirmed with the Trypan blue exclusion test. Thymol in the concentration of 10 µg/mL did not increase DNA damage in AmE-711 honey bee cells, while 100 and 1000 µg/mL concentrations showed genotoxic effects. For testing the antigenotoxic effect, all concentrations of thymol were mixed and incubated with H₂O₂. The antigenotoxic effect against was absent at all concentrations (10, 100, 1000 μg/mL) tested. Moreover, thymol enhanced the H₂O₂-induced DNA migration in the Comet assay. The obtained results indicate genotoxic effects of thymol on cultured honey bee cells suggesting its careful application in beekeeping practice to avoid possible negative effects on honey bees.

Geometry and Segmentation of Cerberus Fossae, Mars: Implications for Marsquake Properties

The NASA InSight mission to Mars successfully landed on 26 November 2018 in Elysium Planitia. It aims to characterize the seismic activity and aid in the understanding of the internal structure of Mars. We focus on the Cerberus Fossae region, a giant fracture network ∼1,200 km long situated east of the InSight landing site where M ∼3 marsquakes were detected during the past 2 years. It is formed of five main fossae located on the southeast of the Elysium Mons volcanic rise. We perform a detailed mapping of the entire system based on high-resolution satellite images and Digital Elevation Models. The refined cartography reveals a range of morphologies associated with dike activity at depth. Width and throw measurements of the fossae are linearly correlated, suggesting a possible tectonic control on the shapes of the fossae. Widths and throws decrease toward the east, indicating the long-term direction of propagation of the dike-induced graben system. They also give insights into the geometry at depth and how the possible faults and fractures are rooted in the crust. The exceptional preservation of the fossae allows us to detect up to four scales of segmentation, each formed by a similar number of 3-4 segments/subsegments. This generic distribution is comparable to continental faults and fractures on Earth. We anticipate higher stress and potential marsquakes within intersegment zones and at graben tips.

Exposure of honey bee larvae to thiamethoxam and its interaction with Nosema ceranae infection in adult honey bees

During their lifetime honey bees (Apis mellifera) rarely experience optimal conditions. Sometimes, a simultaneous action of multiple stressors, natural and chemical, results in even greater effect than of any stressor alone. Therefore, integrative investigations of different factors affecting honey bees have to be carried out. In this study, adult honey bees exposed to thiamethoxam in larval and/or adult stage and infected with Nosema ceranae were examined. Newly emerged bees from colonies, non-treated or treated with thiamethoxam, were organized in six groups and kept in cages. Thiamethoxam treated bees were further exposed to either thiamethoxam or Nosema (groups TT and TN), or simultaneously to both (group TTN). Newly emerged bees from non-treated colonies were exposed to Nosema (group CN). From both, treated and non-treated colonies two groups were organized and further fed only with sugar solution (groups C and TC). Here, we present the expression profile of 19 genes in adult worker honey bees comprising those involved in immune, detoxification, development and apoptosis response. Results showed that gene expression patterns changed with time and depended on the treatment. In group TC at the time of emergence the majority of tested genes were downregulated, among which nine were significantly altered. The same gene pattern was observed on day six, where the only significantly upregulated gene was defensin-1. On day nine most of analyzed genes in all experimental groups showed upregulation compared to control group, where upregulation of antimicrobial peptide genes abaecin, defensin-1 and defensin-2 was significant in groups TT and TTN. On day 15 we observed a similar pattern of expression in groups TC and TT exposed to thiamethoxam only, where most of the detoxification genes were downregulated. Additionally RNA loads of Nosema and honey bee viruses were recorded. We detected a synergistic interaction of thiamethoxam and Nosema, reflected in lowest honey bee survival.

Coexistence of genetically different Varroa destructor in Apis mellifera colonies

The aim of this study was to investigate the genetic diversity of Varroa destructor parasitizing Apis mellifera colonies and to test for possible host-parasite association at the mitochondrial DNA (mtDNA) level. Six A. mellifera haplotypes (including a novel C2aa) and five haplotypes of V. destructor were detected in 29 analyzed colonies from eight sampling sites in Serbia. We revealed the presence of the K and S1 haplotypes as well as KS1 and KP1 heteroplasmic mite individuals in all localities, while the P1 haplotype was only found in four sampling sites. Significant differences in V. destructor genetic diversity were found at both apiary and colony levels, with mite haplotypes coexisting in almost all tested colonies. In addition, a significant correlation between the number of analyzed mites per colony and the number of identified V. destructor haplotypes was observed. However, no significant host-parasite relationship was found, suggesting that mites bearing different haplotypes as well as those heteroplasmic individuals are well adapted to the host, A. mellifera, independently of the identified haplotype present in each colony. Our results will contribute to future population and biogeographic studies concerning V. destructor infesting A. mellifera, as well as to better understanding their host-parasite relationship.

Efficacy of plant-derived formulation “Argus Ras” in Varroa destructor control

Varroa destructor is the most important honey bee parasite. There are various methods used in the control of this mite, but none of them meets all requested criteria, to be safe, effective and easy to apply. The objective of this study was to evaluate the varroacidal efficacy of newly created plant-derived formulation Argus Ras (mixture of extracts of Sophora flavescens, Ginkgo biloba, Gleditsia chinensis and Teucrium chamaedrys) in a field trial. The investigation was conducted on 240 Apis mellifera colonies equalized in respect of brood amount, adult bee population and food reserves. Efficiency was evaluated by applying Argus Ras consecutively with two other acaricides, amitraz and oxalic acid. Average acaricidal efficacy of Argus Ras was 80.89%, being higher of other previously tested essential oils. Besides, it showed a potential in knocking down the mites resistant to other acaricides. It should not be neglected that Argus Ras requires a smaller number of treatments and financial investments than other formulations used for the control of Varroa mites.

Haplotype identification and detection of mitochondrial DNA heteroplasmy in Varroa destructor mites using ARMS and PCR-RFLP methods

In the present study, amplification refractory mutation system (ARMS) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods were used for identification of recently described Serbia 1 (S1) and Peshter 1 (P1) mitochondrial haplotypes of Varroa destructor. Based on single nucleotide polymorphisms (SNPs) within cytochrome oxidase 1 (cox1) and cytochrome b (cytb) gene sequences, a total of 64 adult V. destructor females were analyzed from locations where the S1 and P1 haplotypes had been detected previously. Results of haplotype identification obtained by ARMS and PCR-RFLP methods were completely consistent with the sequencing data. Furthermore, in some analyzed samples the occurrence of site heteroplasmy at haplotype-defining sites was detected, as it was confirmed by double peaks in the sequence chromatograms. Neither mites with simultaneous nucleotide variability, nor those with combined SNP and heteroplasmy in cox1 and cytb were found. Given that this is the first occurrence of site heteroplasmy in V. destructor, the origin of this phenomenon and possible specific traits of heteroplasmic mites have yet to be determined.

Dabigatran for the Treatment and Secondary Prevention of Venous Thromboembolism; A Cost-Effectiveness Analysis for the Netherlands

Background

Dabigatran was proven to have similar effect on the prevention of recurrence of venous thromboembolism (VTE) and a lower risk of bleeding compared to vitamin K antagonists (VKA). The aim of this study is to assess the cost-effectiveness (CE) of dabigatran for the treatment and secondary prevention in patients with VTE compared to VKAs in the Dutch setting.

Methods

Previously published Markov model was modified and updated to assess the CE of dabigatran and VKAs for the treatment and secondary prevention in patients with VTE from a societal perspective in the base-case analysis. The model was populated with efficacy and safety data from major dabigatran trials (i.e. RE-COVER, RECOVER II, RE-MEDY and RE-SONATE), Dutch specific costs, and utilities derived from dabigatran trials or other published literature. Univariate, probabilistic sensitivity and a number of scenario analyses evaluating various decision-analytic settings (e.g. the perspective of analysis, use of anticoagulants only for treatment or only for secondary prevention, or comparison to no treatment) were tested on the incremental cost-effectiveness ratio (ICER).

Results

In the base-case scenario, patients on dabigatran gained an additional 0.034 quality adjusted life year (QALY) while saving €1,598. Results of univariate sensitivity analysis were quite robust. The probability that dabigatran is cost-effective at a willingness-to-pay threshold of €20,000/QALY was 98.1%. From the perspective of healthcare provider, extended anticoagulation with dabigatran compared to VKAs was estimated at €2,158 per QALY gained. The ICER for anticoagulation versus no treatment in patients with equipoise risk of recurrent VTE was estimated at €33,379 per QALY gained. Other scenarios showed dabigatran was cost-saving.

Conclusion

From a societal perspective, dabigatran is likely to be a cost-effective or even cost-saving strategy for treatment and secondary prevention of VTE compared to VKAs in the Netherlands.

Cytological And Molecular Identification Of Haemogregarina Stepanowi In Blood Samples Of The European Pond Turtle (Emys Orbicularis) From Quarantine At Belgrade Zoo

Blood smears stained with Diff Quick are the initial tool for cytological diagnosis of Haemogregarina spp. However, the development of sensitive and specific molecular methods enabled the detection and identification of parasites in the sample and to clarify the evolutionary relationships of adeleorinid parasites within the Apicomplexa.

The current study was attempted in order to perform cytological investigation and molecular identification of the hemoparasites in thirty European pond turtles (Emys orbicularis) from the quarantine section at Belgrade Zoo, which have been found in poor health condition with massive skin hemorrhages, based on intraerythrocytic parasitic forms on hematological smears and 18S rDNA sequence, respectively.

Different life cycle stages of the Haemogregarina sp. were noticed within the erythrocytes in the peripheral blood. Biochemical analysis indicated lower values of AST and iron in most of the infected turtles while hematological analysis showed a changed hematocrit value, a decrease in the number of red blood cells and low hemoglobin levels. Amplifications of the 18S rDNA sequence of Haemogregarina were detected in 30/30 (100%) turtles with clinical symptoms. The identity of PCR products was confirmed by direct DNA sequencing. Future research concerning H. stepanowi in Serbia should be applied to its definitive host-the leech.

Evaluation of the Antigenotoxic Effects of the Royal Sun Mushroom, Agaricus brasiliensis (Higher Basidiomycetes) in Human Lymphocytes Treated with Thymol in the Comet Assay

The aim of this investigation was to evaluate the possible protective activity of Agaricus brasiliensis (=A. blazei sensu Murrill) ethanol extract against thymol-induced DNA damage in human lymphocytes. Before we studied the possible interaction of thymol and A. brasiliensis extract, each component was tested in the comet assay. Thymol significantly increased DNA damage in human lymphocytes at higher concentrations (20, 50, 100, 150, and 200 µg/mL), whereas no genotoxic effect of A. brasiliensis ethanol extract was observed. In simultaneous treatment with thymol (200 µg/mL) and A. brasiliensis ethanol extract (50, 100, 150, and 200 µg/mL), the latter failed to reduce a thymol-induced DNA damaging effect regardless of the applied concentrations. To confirm that thymol induces DNA damage via reactive oxygen species, we performed cotreatment with quercetin. Cotreatment with quercetin (100 and 500 µmol/L) significantly reduced DNA damage caused by thymol (200 µg/mL), indicating that thymol exhibits genotoxicity mainly through induction of reactive oxygen species.

COMPARISON OF METHODS FOR DETECTION OF MICROSPORIDIA SPECIES OF THE GENUS NOSEMA IN HONEY BEES (APIS MELLIFERA)

Two microsporidia species of the Nosema genus cause nosemosis in the adult honeybee: N. apis and N. ceranae. For diagnostic purposes and the determination of infection level various microscopic and molecular biological methods are used. Th e aim of this research was to compare the reliability of the traditional microscopic assessment and two PCR techniques: simplex- and duplex-PCR. Honey bee samples were taken from 150 colonies. Microscopic examination, performed according to the recommendations of the OIE, revealed Nosema spores in 68.67% samples analysed, whilst with the simplex-PCR method all samples (100.0%) proved positive. On the other hand, duplex-PCR method used for the identifi cation of Nosema species resulted in 84.0% positive samples, all of which were N. ceranae. Our recommendation of the simplex-PCR method for the monitoring of honey bees in fi eld conditions is based on its higher reliability than the microscopic assessment in the detection of low-level infections, as well as its potential for the detection of vegetative Nosema sp. stages; thus the early detection and timely prevention of Nosema infection would be possible. Nosema species identifi cation is simplest and most cost-eff ective if performed with the duplex-PCR analysis. However, the simplex-PCR is more reliable, thus, it is suggested that samples that were negative when assessed with microscopy and duplex-PCR analysis undergo simplex-PCR.

Behaviour of non-standard composition copper bearing anodes from the copper refining process

This paper addresses on investigation the possibility of electrolytic treatment the sulphur acidic waste solution, obtained in the conventional electrolytic copper refining process. Beside the high copper concentration, the high concentration of other metals, in this case nickel, is the main characteristic of these waste solutions. Due to this fact, the copper bearing anodes with non-standard nickel, lead, tin and antimony content were specially prepared for the refining process. Nickel content of all anodes was approximately 7.5 mass%, and the content of lead, tin and antimony was varied. The preliminary results, obtained using the standard electrochemical techniques, have indicated that the copper bearing anodes could be used under the same conditions as well as in the conventional copper refining process. The measurements in constant galvanostatic pulse have pointed out that the all chemical elements from copper bearing anodes were dissolved and only copper was deposited onto the cathode. It was also pointed out that Ni concentration in the base working electrolyte (sulphur acidic waste solution), after 72 h of process, increased to 102 mass% at T(1)=63+/-2 degrees C and up to 122 mass% at T(1)=73+/-2 degrees C, while arsenic concentration decreased to a minimum value.

Comparative studies of the serum lipoproteins and lipids in some domestic, laboratory and wild animals

1. The concentration of lipoproteins and lipids in the sera of several species of healthy adult laboratory animals (guinea-pig, rabbit and rat), domestic animals (cattle, sheep, goat, horse and swine) and wild animals (deer, wild boar, mink and fox) have been investigated under physiological conditions. Special attention was paid to the lipoproteins which are precipitated with heparin-MnCl2 and to the ratio of lipids in separated alpha and beta lipoproteins. 2. Most of the studied animals had significantly lower concentrations of total lipoproteins, beta lipoproteins and cholesterol than those in man (P < 0.001). Only some wild animals (mink and fox) had concentrations of total lipoproteins, beta lipoproteins, phospholipids and cholesterol which were significantly higher than man's (P < 0.001). 3. The ratio of lipids in the separated lipoprotein fractions also differed between the examined animals. Thus, in the sheep, rabbit, guinea-pig and wild boar most of the cholesterol (70-76%) was in beta lipoproteins. However, in the horse (60%), mink (60%), fox (65%), goat (70%) and cattle (73%) the high density lipoprotein fraction was the main carrier of cholesterol. 4. With the exception of the guinea-pig (42%) most of the serum phospholipids were found in the high density lipoprotein fraction.