Matrine and Oxymatrine: evaluating the gene mutation potential using in silico tools and the bacterial reverse mutation assay (Ames test).

The quinolizidine alkaloids matrine and its N-oxide oxymatrine occur in plants of the genus Sophora. Recently, matrine was sporadically detected in liquorice products. Morphological similarity of the liquorice plant Glycyrrhiza glabra with Sophora species and resulting confusion during harvesting may explain this contamination, but use of matrine as pesticide has also been reported. The detection of matrine in liquorice products raised concern as some studies suggested a genotoxic activity of matrine and oxymatrine. However, these studies are fraught with uncertainties, putting the reliability and robustness into question. Another issue was that Sophora root extracts were usually tested instead of pure matrine and oxymatrine. The aim of this work was therefore to determine whether matrine and oxymatrine have potential for causing gene mutations. In a first step and to support a weight-of-evidence analysis, in silico predictions were performed to improve the database using expert and statistical systems by VEGA, Leadscope (Instem®), and Nexus (Lhasa Limited). Unfortunately, the confidence levels of the predictions were insufficient to either identify or exclude a mutagenic potential. Thus, in order to obtain reliable results, the bacterial reverse mutation assay (Ames test) was carried out in accordance with OECD Test Guideline 471. The test set included the plate incorporation and the preincubation assay. It was performed with five different bacterial strains in the presence or absence of metabolic activation. Neither matrine nor oxymatrine induced a significant increase in the number of revertants under any of the selected experimental conditions. Overall, it can be concluded that matrine and oxymatrine are unlikely to have a gene mutation potential. Any positive findings with Sophora extracts in the Ames test may be related to other components. Notably, the results also indicated a need to extend the application domain of respective (Q)SAR tools to secondary plant metabolites.

[Psychotherapeutic consultation at work: associations between company size and psychosomatic health]. / Psychotherapeutische Sprechstunde am Arbeitsplatz: Zusammenhänge zwischen Unternehmensgröße und psychosomatischer Gesundheit.

BACKGROUND: The utilization of psychotherapeutic consultation at work (PT-A) has so far been investigated in large enterprises (LEs). These differ structurally from small(est) and medium-sized enterprises (SMEs). Differences in the user profiles of a PT­A with regard to psychosomatic health, work-related self-efficacy, and work ability depending on company size have hardly been investigated. This study also examined differences in the employees' perception of the psychosocial safety climate (PSC) in the company, which represents management's efforts to promote mental health. METHODS: As part of the Early Intervention in the Workplace intervention study called "friaa", employees from LEs and SMEs interested in a PT­A were surveyed throughout Germany from September 2021 to January 2023. Using t­ and χ2-tests, differences between employees in LEs (n = 439) and SMEs (n = 109) were examined with regard to the ICD-10 F diagnostic code ("International Statistical Classification of Diseases and Related Health Problems"; mental and behavioral disorders), depression (PHQ-9), anxiety (GAD-2), level of functioning (GAF), somatic symptom burden (SSS-8), health (VR-12), ability to work (WAI), self-efficacy (SOSES), and psychosocial safety climate (PSC-4). The association between these variables and especially the PSC­4 were investigated using correlation analysis. RESULTS: Both groups showed similar levels of stress. From the employees' perspective, psychosocial issues were addressed significantly more frequently in LEs than in SMEs with a medium effect size. The study provided initial indications that in LEs there were positive correlations of the PSC­4 with SOSES and WAI and negative ones with PHQ­9 and SSS­8. DISCUSSION: The comparable psychological strain on employees in LEs and SMEs points to the need for behavioral and structural preventive measures regardless of the company size. Mainly in SMEs, organizational communication of psychosocial health should be given greater priority.

[Implementation of psychotherapeutic consultation at work (PT-A): expectations, announcement, and use : Results of the friaa-study]. / Implementierung einer psychotherapeutischen Sprechstunde am Arbeitsplatz (PT-A): Erwartungen, Bekanntmachung und Nutzung : Ergebnisse der friaa-Studie.

INTRODUCTION: Psychotherapeutic consultation at work (PT-A) offers easily accessible, short-term support for employees experiencing psychological stress. The aim of the study was to evaluate aspects of the implementation regarding announcement, access, and use of the PT­A. METHODS: The study was conducted as part of a randomized controlled trial (RCT) called "Early Intervention in the Workplace". Forty-six company actors answered a questionnaire about how the companies announced the PT­A to their employees, the barriers in the announcement of the PT­A, and the beneficial factors of using the PT­A. The access routes of the 550 participating employees were used from the baseline data of the RCT. Seven company actors were qualitatively interviewed about their expectations of the PT­A and 22 participants of the RCT were interviewed about their experiences accessing and using the PT­A. RESULTS: The company actors hoped that the PT­A would have an impact on all levels of prevention. Most companies announced the PT­A centrally (e.g., flyers and intranet) as well as through individual recommendations (e.g., through the company's social counselling and occupational health professionals). Employees appreciated the opportunity to participate anonymously in the central announcement. Advantages of the supportive access were seen in the accessibility of employees without treatment experience, employees with high levels of suffering, and employees who have not yet recognized their own need for treatment. DISCUSSION: The results suggest that it is useful to announce the PT­A centrally to all employees but also to recommend it personally to affected employees. By using both methods, different PT­A target groups can be reached and the advantages of anonymous participation are retained.

Genotoxicity assessment: opportunities, challenges and perspectives for quantitative evaluations of dose-response data.

Genotoxicity data are mainly interpreted in a qualitative way, which typically results in a binary classification of chemical entities. For more than a decade, there has been a discussion about the need for a paradigm shift in this regard. Here, we review current opportunities, challenges and perspectives for a more quantitative approach to genotoxicity assessment. Currently discussed opportunities mainly include the determination of a reference point (e.g., a benchmark dose) from genetic toxicity dose-response data, followed by calculation of a margin of exposure (MOE) or derivation of a health-based guidance value (HBGV). In addition to new opportunities, major challenges emerge with the quantitative interpretation of genotoxicity data. These are mainly rooted in the limited capability of standard in vivo genotoxicity testing methods to detect different types of genetic damage in multiple target tissues and the unknown quantitative relationships between measurable genotoxic effects and the probability of experiencing an adverse health outcome. In addition, with respect to DNA-reactive mutagens, the question arises whether the widely accepted assumption of a non-threshold dose-response relationship is at all compatible with the derivation of a HBGV. Therefore, at present, any quantitative genotoxicity assessment approach remains to be evaluated case-by-case. The quantitative interpretation of in vivo genotoxicity data for prioritization purposes, e.g., in connection with the MOE approach, could be seen as a promising opportunity for routine application. However, additional research is needed to assess whether it is possible to define a genotoxicity-derived MOE that can be considered indicative of a low level of concern. To further advance quantitative genotoxicity assessment, priority should be given to the development of new experimental methods to provide a deeper mechanistic understanding and a more comprehensive basis for the analysis of dose-response relationships.

First onset of treatment of patients with eating disorders and treatment course: Results of data from a German health insurance company.

OBJECTIVE: This study examines, inpatient treatment costs, and typical treatment courses of patients with an eating disorder using secondary data. METHOD: The data were provided by a German health insurance company (data from 4.2 million members from 2004 to 2010; corresponds to a market share of 6% of all statutorily insured persons in Germany). An age and gender matched control group without an eating disorder diagnosis was assessed for comparisons from the same dataset. RESULTS: Two thousand seven hundred and thirty four cases with an eating disorder diagnosis (anorexia nervosa [AN], bulimia nervosa [BN] or combination [ANBN]) were identified. The inpatient costs of treatment were €5471.15 for BN, €9080.26 for AN, €10,809.16 for ANBN and €339.37 for the control group. Interestingly, there are numerous mild episodes of eating disorders that could be successfully treated solely on an outpatient basis with a short treatment duration. CONCLUSION: Our findings suggest that course and severity of eating disorders can vary from mild to very severe. Data from health insurance companies depict rather different disease and treatment courses than studies on primary data derived from treatment institutions.

Early intervention, treatment and rehabilitation of employees with common mental disorders by using psychotherapeutic consultation at work: study protocol of a randomised controlled multicentre trial (friaa project).

BACKGROUND: Common mental disorders are one of the leading causes for sickness absence and early retirement due to reduced health. Furthermore, a treatment gap for common mental disorders has been described worldwide. Within this study, psychotherapeutic consultation at work defined as a tailored, module-based and work-related psychotherapeutic intervention will be applied to improve mental health care. METHODS: This study comprises a randomised controlled multicentre trial with 1:1 allocation to an intervention and control group. In total, 520 employees with common mental disorders shall be recruited from companies being located around five study centres in Germany. Besides care as usual, the intervention group will receive up to 17 sessions of psychotherapy. The first session will include basics diagnostics and medical indication of treatment and the second session will include work-related diagnostics. Then, participants of the intervention group may receive work-related psychotherapeutic consultation for up to ten sessions. Further psychotherapeutic consultation during return to work for up to five sessions will be offered where appropriate. The control group will receive care as usual and the first intervention session of basic diagnostics and medical indication of treatment. After enrolment to the study, participants will be followed up after nine (first follow-up) and fifteen (second follow-up) months. Self-reported days of sickness absence within the last 6 months at the second follow-up will be used as the primary outcome and self-efficacy at the second follow-up as the secondary outcome. Furthermore, a cost-benefit assessment related to costs of common mental disorders for social insurances and companies will be performed. DISCUSSION: Psychotherapeutic consultation at work represents a low threshold care model aiming to overcome treatment gaps for employees with common mental disorders. If successfully implemented and evaluated, it might serve as a role model to the care of employees with common mental disorders and might be adopted in standard care in cooperation with sickness and pension insurances in Germany. TRIAL REGISTRATION: The friaa project was registered at the German Clinical Trial Register (DRKS) at 01.03.2021 (DRKS00023049): https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00023049 .

[Providing Rapid Help for Mental Strain at the Workplace: Psychosomatic Consultation in the Workplace]. / Rasche Hilfe bei psychischen Belastungen am Arbeitsplatz: Die Psychosomatische Sprechstunde im Betrieb.

BACKGROUND: Psychosomatic consultation in the workplace (PSIW) is an offer for employees who are under mental and psychosomatic strain. Core elements are early diagnosis and short-term psychotherapy with the aim of improving the care for mentally stressed employees. This article provides a characterization of patients and presents initial data on the effects of short-term psychotherapy. MATERIALS AND METHODS: From 05/2016 to 12/2019, basic data were collected from all employees seeking help. Socio-demographic data, previous treatments, work ability, depression (PHQ-9), anxiety (GAD-7), somatic symptoms (PHQ-15), assessment of psychological state and attitudes towards treatment options were collected by self-report before and (if applicable) after a short-term intervention. RESULTS: A total of 672 employees from 20 companies (49% male) were mostly referred to PSIW by the company physician. Adjustment disorders and depressive disorders each accounted for almost one-third of diagnoses. A quarter of the employees presenting at PSIW were on sick leave at the time of referral. The most frequent recommendations were short-term intervention at PSIW, followed by outpatient psychotherapy. A total of 343 (51%) employees completed the questionnaires, of which 187 (55%) of them received short-term psychotherapy. The symptoms improved significantly across all scales. Satisfaction with PSIW was very high. CONCLUSIONS: PSIW is an innovative care concept in the work context, which is well accepted and effective in various sectors. Close cooperation with company stakeholders such as occupational health physicians is important for a successful outcome.

Methyleugenol DNA adducts in human liver are associated with SULT1A1 copy number variations and expression levels.

Methyleugenol is a rodent hepatocarcinogen occurring in many herbs and spices as well as essential oils used for flavoring. Following metabolic activation by cytochromes P450 (CYPs) and sulfotransferases (SULTs), methyleugenol can form DNA adducts. Previously, we showed that DNA adduct formation by methyleugenol in mouse liver is dependent on SULT1A1 expression and that methyleugenol DNA adducts are abundant in human liver specimens. In humans, SULT1A1 activity is affected by genetic polymorphisms, including single-nucleotide polymorphisms (SNPs) and copy number variations (CNVs). Here we investigated the relationship between individual methyleugenol DNA adduct levels and SULT1A1 in human liver samples. Using isotope-dilution ultraperformance liquid chromatography coupled with tandem mass spectrometry, we quantified methyleugenol DNA adducts in 121 human surgical liver samples. Frequent CNVs, including deletions (f = 3.3%) and duplications (f = 36.4%) of SULT1A1, were identified using qPCR and TaqMan assays in the donors' genomic DNA. SULT1A1 mRNA and protein levels were quantified using microarray data and Western blot analysis, respectively. Methyleugenol DNA adducts were detected in all 121 liver samples studied. Their levels varied 122-fold between individuals and were significantly correlated to both mRNA and protein levels of SULT1A1 (r s = 0.43, and r s = 0.44, respectively). Univariate and multivariate statistical analysis identified significant associations of SULT1A1 CNVs with mRNA (p = 1.7 × 10-06) and protein (p = 4.4 × 10- 10) levels as well as methyleugenol DNA adduct levels (p = 0.003). These data establish the importance of SULT1A1 genotype for hepatic methyleugenol DNA adducts in humans, and they confirm a strong impact of SULT1A1 CNVs on SULT1A1 hepatic phenotype.

Simultaneous detection of multiple DNA adducts in human lung samples by isotope-dilution UPLC-MS/MS.

Recent studies have demonstrated that various DNA adducts can be detected in human tissues and fluids using liquid chromatography connected to tandem mass spectrometry (LC-MS/MS). However, the utility of a single DNA adduct as a biomarker in risk assessment is debatable because humans are exposed to many genotoxicants. We established a method to measure DNA adducts derived from 16 ubiquitous genotoxicants and developed an analytical technique for their simultaneous quantification by ultra performance liquid chromatography (UPLC)-MS/MS. Methods for the enrichment of the analytes from DNA hydrolysates and chromatographic separation preceding mass spectrometric analysis were optimized, and the resultant technique was used for the simultaneous analysis of the 16 DNA adducts in human lung biopsy specimens. Eleven adducts (formed by benzo[a]pyrene, 1-methylpyrene, 4-aminobiphenyl, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, 1-methoxy-3-indolylmethylglucosinolate, 5-hydroxymethylfurfural, and malondialdehyde) were not detected in any tissue sample (limits of detection: 0.02-7.1 adducts/10(8) nucleosides). 3,N(4)-etheno-2'-deoxycytidine and 1,N(6)-etheno-2'-deoxyadenosine, formed from 2,3-epoxyaldehydes of endogenous lipid peroxidation products, were present in all subjects (16.9-115.3 and 27.2-179/10(8) nucleosides, respectively). The same was true for N(2)-(trans-methylisoeugenol-3'-yl)-2'-deoxyguanosine, the major adduct of methyleugenol (1.7-23.7/10(8) nucleosides). A minor adduct of methyleugenol and two adducts of furfuryl alcohol were detected in several pulmonary specimens. Taken together, we developed a targeted approach for the simultaneous mass spectrometric analyses of 16 DNA adducts, which can be easily extended by adducts formed from other mutagens. The method allowed one to detect adducts of furfuryl alcohol and methyleugenol in samples of human lung.

Formation of hepatic DNA adducts by methyleugenol in mouse models: drastic decrease by Sult1a1 knockout and strong increase by transgenic human SULT1A1/2.

Methyleugenol--a natural constituent of herbs and spices--is hepatocarcinogenic in rodent models. It can form DNA adducts after side-chain hydroxylation and sulfation. We previously demonstrated that human sulfotransferases (SULTs) 1A1 and 1A2 as well as mouse Sult1a1, expressed in Salmonella target strains, are able to activate 1'-hydroxymethyleugenol (1'-OH-ME) and 3'-hydroxymethylisoeugenol (3'-OH-MIE) to mutagens. Now we investigated the role of these enzymes in the formation of hepatic DNA adducts by methyleugenol in the mouse in vivo. We used FVB/N mice [wild-type (wt)] and genetically modified strains in this background: Sult1a1 knockout (ko), transgenic for human SULT1A1/2 (tg) and the combination of both modifications (ko-tg). Methyleugenol (50mg/kg body mass) formed 23, 735, 3770 and 4500 N (2)-(trans-methylisoeugenol-3'-yl)-2'-deoxyguanosine adducts per 10(8) 2'-deoxyribonucleosides (dN) in ko, wt, ko-tg and tg mice, respectively. The corresponding values for an equimolar dose of 1'-OH-ME were 12, 1490, 12 400 and 13 300 per 10(8) dN. Similar relative levels were observed for the minor adduct, N (6)-(trans-methylisoeugenol-3'-yl)-2'-deoxyadenosine. Thus, the adduct formation by both compounds was nearly completely dependent on the presence of SULT1A enzymes, with human SULT1A1/2 producing stronger effects than mouse Sult1a1. Moreover, a dose of 0.05 mg/kg methyleugenol (one-fourth of the estimated average daily exposure of humans) was sufficient to form detectable adducts in humanized (ko-tg) mice. Although 3'-OH-MIE was equally mutagenic to 1'-OH-ME in Salmonella strains expressing human SULT1A1 or 1A2, it only formed 0.14% of hepatic adducts in ko-tg mice compared with an equimolar dose of 1'-OH-ME, suggesting an important role of detoxifying pathways for this isomer in vivo.

Abundance of DNA adducts of methyleugenol, a rodent hepatocarcinogen, in human liver samples.

Methyleugenol is a genotoxic carcinogen in mice and rats, the liver being the primary target tissue. Methyleugenol occurs in fennel and many herbs and spices. Furthermore, methyleugenol-containing plant extracts and chemically prepared methyleugenol are used as flavoring agents. We analyzed surgical human liver samples from 30 subjects for the presence of DNA adducts originating from methyleugenol using isotope-dilution ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Twenty-nine samples unambiguously contained the N (2)-(trans-methylisoeugenol-3'-yl)-2'-deoxyguanosine adduct. A second adduct, N (6)-(trans-methylisoeugenol-3'-yl)-2'-deoxyadenosine, was also found in most samples, but at much lower levels, in agreement with the results from experimental models. The maximal and median levels of both adducts combined were 37 and 13 per 10(8) nucleosides (corresponding to 4700 and 1700, respectively, adducts per diploid genome). This is the first demonstration of DNA adducts formed by a xenobiotic in human liver using UPLC-MS/MS, the most reliable method available. It has been estimated for diverse rat and mouse hepatocarcinogens that 50-5500 adducts per 10(8) nucleosides are present after repeated treatment at the TD50 (daily dose that halves the probability to stay tumor-free in long-term studies). We conclude that the exposure to methyleugenol leads to substantial levels of hepatic DNA adducts and, therefore, may pose a significant carcinogenic risk.

Optimized enzymatic hydrolysis of DNA for LC-MS/MS analyses of adducts of 1-methoxy-3-indolylmethyl glucosinolate and methyleugenol.

Mass spectrometric analyses of DNA adducts usually require enzymatic digestion of the DNA to nucleosides. The digestive enzymes used in our laboratory included a calf spleen phosphodiesterase, whose marketing was stopped recently. Using DNA adducted with bioactivated methyleugenol and 1-methoxy-3-indolylmethyl glucosinolate-each forming dA and dG adducts-we demonstrate that replacement of calf spleen phosphodiesterase (Merck) with bovine spleen phosphodiesterase (Sigma-Aldrich) leads to unchanged results. Enzyme levels used for DNA digestion are extremely variable in different studies. Therefore, we sequentially varied the level of each of the three enzymes used. All dose (enzyme)-response (adduct level) curves involved a long plateau starting below the enzyme levels employed previously. Thus, we could reduce the amounts of micrococcal nuclease, phosphodiesterase, and alkaline phosphatase for quantitative DNA digestion by factors of 4, 2, and 333, respectively, compared to our previous protocols. Moreover, we observed significant phosphatase activity of both phosphodiesterase preparations used, which may affect the recovery of adducts with methods requiring digestion to 2'-deoxynucleoside-3'-monophosphates (e.g., (32)P-postlabeling). In addition, the phosphodiesterase from Sigma-Aldrich, but not that from Merck, deaminated dA. This was irrelevant for the dA adducts studied, involving bonding at N(6), but might complicate the analysis of other dA adducts.

Identification of human and murine sulfotransferases able to activate hydroxylated metabolites of methyleugenol to mutagens in Salmonella typhimurium and detection of associated DNA adducts using UPLC-MS/MS methods.

Methyleugenol, a secondary metabolite present in many herbal spices, is carcinogenic in various tissues of mice and rats but negative in standard in vitro mutagenicity tests. Several observations indicate that hydroxylation followed by sulfation is an important activation pathway in the carcinogenicity and DNA adduct formation by methyleugenol and other alkenylbenzenes in animal models. However, sulfation is not taken into account in standard in vitro tests. Therefore, we have studied whether expression of murine or human sulfotransferases (SULTs) in the target strain, Salmonella typhimurium TA100, leads to the activation of hydroxylated metabolites of methyleugenol [(+)-1'-hydroxymethyleugenol, (-)-1'-hydroxymethyleugenol and (E)-3'-hydroxymethylisoeugenol]. Human SULT1A1 (a form expressed at high levels in many tissues) and SULT1C2 (expressed primarily in foetal tissues) activated all three compounds even at very low substrate concentrations. At higher concentrations, activation was also observed with human SULT1A2 and SULT1E1. Murine Sult1a1 required higher substrate concentrations than its human orthologue. Other SULT forms (human 1A3, 1C1, 1C3, 2A1 and 2B1b as well as murine 1d1) did not activate any methyleugenol metabolites studied. Furthermore, we developed isotope-dilution mass-spectrometric methods for the sensitive and specific detection of DNA adducts formed by methyleugenol metabolites. All three hydroxylated metabolites formed the same DNA adducts in S. typhimurium TA100-hSULT1A1: high levels of N (2)-(trans-methylisoeugenol-3'-yl)-2'-deoxyguanosine and modest levels of N (6)-(trans-methylisoeugenol-3'-yl)-2'-deoxyadenosine. Adduct levels correlated with the mutagenic effects induced. No adducts were formed by the test compounds in the SULT-deficient standard strain TA100. In conclusion, several methyleugenol metabolites are activated to DNA-reactive mutagens in S. typhimurium upon incorporation of appropriate sulfation capacity. We have identified human and murine SULT forms able to catalyse this activation. Methods were developed that may be utilised to analyse DNA samples from human tissues specifically for the possible presence of methyleugenol adducts.

Migration as an escape from parasitism in New Zealand galaxiid fishes.

Parasite avoidance is increasingly considered to be a potential driving factor in animal migrations. In many marine and freshwater benthic fish, migration into a pelagic environment by developing larvae is a common life history trait that could reduce exposure to parasites during a critical window of developmental susceptibility. We tested this hypothesis on congeneric fish (family Galaxiidae, genus Galaxias) belonging to a closely related species complex sampled from coastal streams in southeastern New Zealand. Migratory Galaxias have larvae that migrate to pelagic marine environments, whereas the larvae of non-migratory species rear close to adult habitats with no pelagic larval phase. Both migratory and non-migratory fish are hosts to two species of skin-penetrating trematodes that cause spinal malformations and high mortality in young fish. Using generalized linear models within an Akaike information criterion and model averaging framework, we compared infection levels between migratory and non-migratory fish while taking into account body size and several other local factors likely to influence infection levels. For one trematode species, we found a significant effect of migration: for any given body length, migratory fish harboured fewer parasites than non-migratory fish. Also, no parasites of any kind were found in juvenile migratory fish sampled in spring shortly after their return to stream habitats. Our results demonstrate that migration spares juvenile fish from the debilitating parasites to which they would be exposed in adult stream habitats. Therefore, either the historical adoption of a migratory strategy in some Galaxias was an adaptation against parasitism, or it evolved for other reasons and now provides protection from infection as a coincidental side-effect.

Use of transcriptomics in hazard identification and next generation risk assessment: A case study with clothianidin.

Toxicological risk assessment is essential in the evaluation and authorization of different classes of chemical substances. Genotoxicity and mutagenicity testing are of highest priority and rely on established in vitro systems with bacterial and mammalian cells, sometimes followed by in vivo testing using rodent animal models. Transcriptomic approaches have recently also shown their value to determine transcript signatures specific for genotoxicity. Here, we studied how transcriptomic data, in combination with in vitro tests with human cells, can be used for the identification of genotoxic properties of test compounds. To this end, we used liver samples from a 28-day oral toxicity study in rats with the pesticidal active substances imazalil, thiacloprid, and clothianidin, a neonicotinoid-type insecticide with, amongst others, known hepatotoxic properties. Transcriptomic results were bioinformatically evaluated and pointed towards a genotoxic potential of clothianidin. In vitro Comet and γH2AX assays in human HepaRG hepatoma cells, complemented by in silico analyses of mutagenicity, were conducted as follow-up experiments to check if the genotoxicity alert from the transcriptomic study is in line with results from a battery of guideline genotoxicity studies. Our results illustrate the combined use of toxicogenomics, classic toxicological data and new approach methods in risk assessment. By means of a weight-of-evidence decision, we conclude that clothianidin does most likely not pose genotoxic risks to humans.

Metabolic activation of furfuryl alcohol: formation of 2-methylfuranyl DNA adducts in Salmonella typhimurium strains expressing human sulfotransferase 1A1 and in FVB/N mice.

Furfuryl alcohol, formed by acid- and heat-induced dehydration from pentoses, is found in many foodstuffs. It induced renal tubule neoplasms in male B6C3F1 mice and nasal neoplasms in male F344/N rats in a study of the National Toxicology Program (NTP). However, furfuryl alcohol was negative in the standard Ames test and in a battery of in vivo mutagenicity tests. Here, we show that furfuryl alcohol is mutagenic in Salmonella typhimurium TA100 engineered for expression of human sulfotransferase (SULT) 1A1. This finding suggests that furfuryl alcohol is converted by intracellular sulfo conjugation to 2-sulfo-oxymethylfuran, an electrophile reacting with DNA. We detected nucleoside adducts of 2'-deoxyadenosine, 2'-deoxyguanosine and 2'-deoxycytidine in porcine liver DNA incubated with freshly prepared 2-sulfo-oxymethylfuran. The main adducts, N(2)-((furan-2-yl)methyl)-2'-deoxyguanosine (N(2)-MFdG) and N(6)-((furan-2-yl)methyl)-2'-deoxyadenosine (N(6)-MFdA) were synthesized. Their structures were verified by NMR and mass spectrometry. Liquid chromatography-tandem mass spectrometry methods for the quantification of both adducts were devised. N(2)-MFdG and N(6)-MFdA were detected in DNA of furfuryl alcohol-exposed S.typhimurium TA100 expressing SULT1A1 and in DNA of liver, lung and kidney of FVB/N mice that had received ∼390 mg furfuryl alcohol/kg body wt/day via the drinking water for 28 days. In summary, furfuryl alcohol is converted by sulfo conjugation to a mutagen. The detection of N(2)-MFdG and N(6)-MFdA in renal DNA of furfuryl alcohol-treated mice suggests that the neoplasms observed in this tissue in the study of the NTP may have been induced by 2-sulfo-oxymethylfuran.

Encystment site affects the reproductive strategy of a progenetic trematode in its fish intermediate host: is host spawning an exit for parasite eggs?

Each transmission event in complex, multi-host life cycles create obstacles selecting for adaptations by trematodes. One such adaptation is life cycle abbreviation through progenesis, in which the trematode precociously matures and reproduces within the second intermediate host. Progenesis eliminates the need for the definitive host and increases the chance of life cycle completion. However, progenetic individuals face egg-dispersal challenges associated with reproducing within metacercarial cysts in the tissues or body cavity of the second intermediate host. Most progenetic species await host death for their eggs to be released into the environment. The present study investigated temporal variation of progenesis in Stegodexamene anguillae in one of its second intermediate fish hosts and the effect of the fish's reproductive cycle on progenesis. The study involved monthly sampling over 13 months at one locality. A greater proportion of individuals became progenetic in the gonads of female fish hosts. Additionally, progenesis of worms in the gonads was correlated with seasonal daylight and temperature changes, major factors controlling fish reproduction. Host spawning events are likely to be an avenue of egg dispersal for this progenetic species, with the adoption of progenesis being conditional on whether or not the parasite can benefit from fish spawning.

Alkenylbenzenes in Foods: Aspects Impeding the Evaluation of Adverse Health Effects.

Alkenylbenzenes are naturally occurring secondary plant metabolites, primarily present in different herbs and spices, such as basil or fennel seeds. Thus, alkenylbenzenes, such as safrole, methyleugenol, and estragole, can be found in different foods, whenever these herbs and spices (or extracts thereof) are used for food production. In particular, essential oils or other food products derived from the aforementioned herbs and spices, such as basil-containing pesto or plant food supplements, are often characterized by a high content of alkenylbenzenes. While safrole or methyleugenol are known to be genotoxic and carcinogenic, the toxicological relevance of other alkenylbenzenes (e.g., apiol) regarding human health remains widely unclear. In this review, we will briefly summarize and discuss the current knowledge and the uncertainties impeding a conclusive evaluation of adverse effects to human health possibly resulting from consumption of foods containing alkenylbenzenes, especially focusing on the genotoxic compounds, safrole, methyleugenol, and estragole.

New evidence on a cold case: trophic transmission, distribution and host-specificity in Hedruris spinigera (Nematoda: Hedruridae).

The life cycle of Hedruris spinigera Baylis, 1931 (Nematoda: Hedruridae) is determined here with the first formal identification of the parasite's intermediate host: the crustacean amphipod Paracorophium excavatum Thomson. Adult H. spinigera are redescribed from specimens collected from the stomach of fishes, Retropinna retropinna (Richardson) and Aldrichettaforsteri (Valenciennes), from Lake Waihola, New Zealand. Immature adults of the parasite collected from intermediate hosts (P. excavatum) are also described for the first time. The prevalence, abundance and intensity of infection of H. spinigera in several fish species are quantified along with the occurrence of P. excavatum, the parasite's intermediate host, in fish stomach contents. Although H. spinigera's transmission mode (trophic transmission) and fish diet potentially expose all fish species to infection, some level of host specificity must exist as parasite prevalence, abundance and intensity of infection vary greatly between potential definitive host species. We suggest here that the anatomy of the fish digestive tract and especially that of the stomach plays an important role in host suitability for H. spinigera. While P. excavatum is the only intermediate host in Lake Waihola, H. spinigera was found in six different fish species: Aldrichetta forsteri, Galaxias maculatus (Jenyns), Retropinna retropinna, Rhombosolea retiaria Hutton, Perca fluviatilis Linnaeus and Salmo trutta Linnaeus; although typical hedrurid attachment and mating positions were observed only in R. retropinna and A. forsteri. The limited distribution of H. spinigera is most likely due to that of its different host species (intermediate and definitive), all inhabitants of coastal fresh and brackish waters.

Parasitism in Gambusia affinis: Fitness Effects in an Incipient Matrotroph.

Gambusia affinis (western mosquitofish) serves as a host for a variety of larval and adult parasites. Gambusia affinis is also an incipient matrotroph, exhibiting adjustments in post-fertilization provisioning to some offspring within a brood using recently acquired resources. Nutrient transfer to embryos is expected to limit the loss of embryo mass during development resulting in larger offspring. Since larger offspring are more likely to survive, maternal contributions are expected to increase fitness. The presence of parasites, particularly intestinal helminths, potentially reduces body condition and resources available for developing offspring, thereby reducing host fitness. The effects of parasitism on the fitness of G. affinis were investigated in the present study. Fish were collected from 3 sites monthly from June 2015 through August 2016. All helminth parasites were collected during necropsy and identified. Brood size and embryo developmental stage were recorded for each female fish. Additionally, 10 ova/embryos of each developmental stage from each female fish collected from May through August 2016 were haphazardly selected and individually weighed. From 429 female mosquitofish, 5,072 helminths were collected. Brood size varied among collection sites and was positively influenced by maternal body condition, the number of daylight hours, water temperature, and the intensity of both plerocercoid and adult Schyzocotyle acheilognathi. However, brood size was negatively related to the intensity of Neoechinorhynchus cylindratus cystacanth and an increasing number of days between collection and dissection. Embryo weight increased with the presence of either Camallanidae or Contracaecum multipapulatum, embryo developmental stage, and relative host density. These results indicate that some parasitic helminth species negatively affect the fitness of G. affinis, while some positively affect fitness, and that effect can vary with intensity.