Behavioural responses to dimethyl disulphide by Aleochara bilineata and Aleochara bipustulata

Adult Aleochara bipustulata L. and Aleochara bilineata Gyllenhal (Coleoptera: Staphylinidae) are predatory on immature stages of cabbage root fly Delia radicum (L.) (Diptera: Anthomyiidae). Larvae of the two Aleochara are parasitoids of D. radicum pupae. Female Aleochara lay eggs near D. radicum puparia; the newly‐hatched Aleochara larvae enter puparia and consume the contents. Delia radicum‐infested roots of brassicas give off dimethyl disulphide (DMDS). In the field, DMDS attracts adult Aleochara to pitfall traps but does not enhance the biological control of D. radicum. In the present study, we investigate the behavioural responses of the Aleochara to DMDS in still air, as well as in moving air in a Y‐tube olfactometer, and also investigate the influence of DMDS on host selection. In larvae of both Aleochara species, DMDS induces a restricted‐area search in still air, resulting in elevated frequencies of attack of D. radicum puparia close to a source of DMDS. In the olfactometer, newly‐emerged virgin adults of both sexes of both Aleochara species choose alternatives to DMDS, older recently‐mated females are attracted to DMDS, and older males and older mate‐deprived females show no preference. Mating status of males determines the switch of their response to DMDS from avoidance to indifference. We conclude that DMDS is an important cue for host‐finding, although other cues are involved in mate‐finding. We discuss the implications for use of DMDS to enhance D. radicum mortality and for parasitism of nontarget species if A. bipustulata is introduced to Canada for biological control of D. radicum.     

Stability and resilience of the intestinal microbiota in children in daycare – a 12 month cohort study

Background

We performed a 12-month cohort study of the stability and resilience of the intestinal microbiota of healthy children in daycare in Denmark in relation to diarrheal events and exposure to known risk factors for gastrointestinal health such as travelling and antibiotic use. In addition, we analyzed how gut microbiota recover from such exposures.

Results

We monitored 32 children in daycare aged 1–6?years. Fecal samples were submitted every second month during a one-year observational period. Information regarding exposures and diarrheal episodes was obtained through questionnaires. Bacterial communities were identified using 16S rRNA gene sequencing. The core microbiota (mean abundance >?95%) dominated the intestinal microbiota, and none of the tested exposures (diarrheal events, travel, antibiotic use) were associated with decreases in the relative abundance of the core microbiota. Samples exhibited lower intra-individual variation than inter-individual variation. Half of all the variation between samples was explained by which child a sample originated from. Age explained 7.6–9.6% of the variation, while traveling, diarrheal events, and antibiotic use explained minor parts of the beta diversity. We found an age-dependent increase of alpha diversity in children aged 1–3?years, and while diarrheal events caused a decrease in alpha diversity, a recovery time of 40–45?days was observed.Among children having had a diarrheal event, we observed a 10x higher relative abundance of Prevotella. After travelling, a higher abundance of two Bacteroides species and 40% less Lachnospiraceae were seen. Antibiotic use did not correlate with changes in the abundance of any bacteria.

Conclusion

We present data showing that Danish children in daycare have stable intestinal microbiota, resilient to the exposures investigated. An early age-dependent increase in the diversity was demonstrated. Diarrheal episodes decreased alpha diversity with an estimated recovery time of 40–45?days.

     

2,3-Dideoxy-3-Phthalimidopentoses in the Synthesis of 3′-Amino-2′,3′-Dideoxynucleosides

Abstract

3′-Amino-3′deoxythymidine is a very effective drug in vivo against L 1210 leukemia. It mives 1441 increase in lifespan with very little drug-induced toricitylil. Therefore, it was attractive to synthesize a large series of cuialogues, but unfortunately, such compounds are only achievable through a 1inear synthesis via the corresponding nucleoside which typically is transformed into the 3′-azido derivative and finally reduced.     

Aversive Event Anticipation Affects Connectivity between the Ventral Striatum and the Orbitofrontal Cortex in an fMRI Avoidance Task

Ability to anticipate aversive events is important for avoiding dangerous or unpleasant situations. The motivation to avoid an event is influenced by the incentive salience of an event-predicting cue. In an avoidance fMRI task we used tone intensities to manipulate salience in order to study the involvement of the orbitofrontal cortex in processing of incentive salience. In the task, cues predicting either aversive or neutral avoidable tones were presented. Ventral striatum, amygdala and anterior insula activations were significantly stronger during presentation of cues for aversive than neutral tones. A psychophysiological interaction analysis showed stronger connectivity between the ventral striatum and the orbitofrontal cortex during aversive than neutral conditions. The present study shows an interaction between the ventral striatum, a structure previously linked to negative incentive salience, and the orbitofrontal cortex supporting a role for this region in processing salience. In addition, this study replicates previous findings suggesting that the task is robust.     

Relationships between native small mammals and native and introduced large herbivores

Australia has a range of native and introduced large herbivores that could affect the abundance of small mammals through direct and indirect effects. Here we study the relationship between occurrence of the introduced rusa deer (Rusa timorensis) and the native swamp wallaby (Wallabia bicolor), and the abundance of four species of native small mammals in coastal heath vegetation with varying fire history. The abundance of two species, the brown antechinus (Antechinus stuartii) and bush rat (Rattus fuscipes), was related to occurrence of large herbivores and was dependent also on fire history. Abundance of swamp rats (R. lutreolus) and New Holland mice (Pseudomys novaehollandiae) was not related to the occurrence of any of the large herbivores, and did not depend on fire history. At sites burned within the last 9 years, captures of brown antechinus were negatively related to both deer and wallaby occurrence, and captures of bush rats were negatively related to deer occurrence. However, at sites that burned more than 15 years ago, captures of brown antechinus and bush rats were not related to large herbivore occurrence. Overall there was either no relationship, or a negative one, between small mammals and the large herbivores. This mensurative study has demonstrated relationships between deer and wallabies and small mammals, with fire as an additional important factor. From the results of the current study we put forward a series of hypotheses that need to be tested by future experiments.     

PALB2: The hub of a network of tumor suppressors involved in DNA damage responses

PALB2 was first identified as a partner of BRCA2 that mediates its recruitment to sites of DNA damage. PALB2 was subsequently found as a tumor suppressor gene. Inherited heterozygosity for this gene is associated with an increased risk of cancer of the breast and other sites. Additionally, biallelic mutation of PALB2 is linked to Fanconi anemia, which also has an increased risk of developing malignant disease. Recent work has identified numerous interactions of PALB2, suggesting that it functions in a network of proteins encoded by tumor suppressors. Notably, many of these tumor suppressors are related to the cellular response to DNA damage. The recruitment of PALB2 to DNA double-strand breaks at the head of this network is via a ubiquitin-dependent signaling pathway that involves the RAP80, Abraxas and BRCA1 tumor suppressors. Next, PALB2 interacts with BRCA2, which is a tumor suppressor, and with the RAD51 recombinase. These interactions promote DNA repair by homologous recombination (HR). More recently, PALB2 has been found to bind the RAD51 paralog, RAD51C, as well as the translesion polymerase pol η, both of which are tumor suppressors with functions in HR. Further, an interaction with MRG15, which is related to chromatin regulation, may facilitate DNA repair in damaged chromatin. Finally, PALB2 interacts with KEAP1, a regulator of the response to oxidative stress. The PALB2 network appears to mediate the maintenance of genome stability, may explain the association of many of the corresponding genes with similar spectra of tumors, and could present novel therapeutic opportunities.     

The human DEK oncogene regulates DNA damage response signaling and repair

The human DEK gene is frequently overexpressed and sometimes amplified in human cancer. Consistent with oncogenic functions, Dek knockout mice are partially resistant to chemically induced papilloma formation. Additionally, DEK knockdown in vitro sensitizes cancer cells to DNA damaging agents and induces cell death via p53-dependent and -independent mechanisms. Here we report that DEK is important for DNA double-strand break repair. DEK depletion in human cancer cell lines and xenografts was sufficient to induce a DNA damage response as assessed by detection of γH2AX and FANCD2. Phosphorylation of H2AX was accompanied by contrasting activation and suppression, respectively, of the ATM and DNA-PK pathways. Similar DNA damage responses were observed in primary Dek knockout mouse embryonic fibroblasts (MEFs), along with increased levels of DNA damage and exaggerated induction of senescence in response to genotoxic stress. Importantly, Dek knockout MEFs exhibited distinct defects in non-homologous end joining (NHEJ) when compared to their wild-type counterparts. Taken together, the data demonstrate new molecular links between DEK and DNA damage response signaling pathways, and suggest that DEK contributes to DNA repair.     

Surviving winter: Food,but not habitat structure,prevents crashes in cyclic vole populations

Vole population cycles are a major force driving boreal ecosystem dynamics in northwestern Eurasia. However, our understanding of the impact of winter on these cycles is increasingly uncertain, especially because climate change is affecting snow predictability, quality, and abundance. We examined the role of winter weather and snow conditions, the lack of suitable habitat structure during freeze‐thaw periods, and the lack of sufficient food as potential causes for winter population crashes. We live‐trapped bank voles Myodes glareolus on 26 plots (0.36 ha each) at two different elevations (representing different winter conditions) in southeast Norway in the winters 2013/2014 and 2014/2015. We carried out two manipulations: supplementing six plots with food to eliminate food limitation and six plots with straw to improve habitat structure and limit the effect of icing in the subnivean space. In the first winter, all bank voles survived well on all plots, whereas in the second winter voles on almost all plots went extinct except for those receiving supplemental food. Survival was highest on the feeding treatment in both winters, whereas improving habitat structure had no effect. We conclude that food limitation was a key factor in causing winter population crashes.     

A Genetic Deconstruction of Neurocognitive Traits in Schizophrenia and Bipolar Disorder

Background

Impairments in cognitive functions are common in patients suffering from psychiatric disorders, such as schizophrenia and bipolar disorder. Cognitive traits have been proposed as useful for understanding the biological and genetic mechanisms implicated in cognitive function in healthy individuals and in the dysfunction observed in psychiatric disorders.

Methods

Sets of genes associated with a range of cognitive functions often impaired in schizophrenia and bipolar disorder were generated from a genome-wide association study (GWAS) on a sample comprising 670 healthy Norwegian adults who were phenotyped for a broad battery of cognitive tests. These gene sets were then tested for enrichment of association in GWASs of schizophrenia and bipolar disorder. The GWAS data was derived from three independent single-centre schizophrenia samples, three independent single-centre bipolar disorder samples, and the multi-centre schizophrenia and bipolar disorder samples from the Psychiatric Genomics Consortium.

Results

The strongest enrichments were observed for visuospatial attention and verbal abilities sets in bipolar disorder. Delayed verbal memory was also enriched in one sample of bipolar disorder. For schizophrenia, the strongest evidence of enrichment was observed for the sets of genes associated with performance in a colour-word interference test and for sets associated with memory learning slope.

Conclusions

Our results are consistent with the increasing evidence that cognitive functions share genetic factors with schizophrenia and bipolar disorder. Our data provides evidence that genetic studies using polygenic and pleiotropic models can be used to link specific cognitive functions with psychiatric disorders.