Spatio-temporal variation in species assemblages in field edges: seasonally distinct responses of solitary bees to local habitat characteristics and landscape conditions

The bees (Hymenoptera: Apiformes) are important pollinators in many ecosystems, but their diversity has declined in Europe during the past century, mainly due to habitat loss. However, some of the habitat requirements of wild bees are met in anthropogenic landscape elements, such as road sides, power-line strips and field edges. Moreover, as the bee species assemblages change throughout the season the habitat requirements of the bee fauna may change accordingly. Understanding such seasonally distinct responses of solitary bees with different phenologies may be of high value for local conservation planning. The purpose of this study was to examine if the habitat quality of field edges for solitary bees change throughout the season, and how this temporal variation relates to local habitat and landscape conditions. By sampling solitary bees in 18 field edges in southeast Norway throughout the season we found that the species richness and abundance of bees was highest in sun exposed field edges, independently of the season. However, we found phenologically distinct responses to the landscape context. Moreover, field edges situated in landscapes with a high proportion of forests and semi-natural landscape elements hosted the most phenologically diverse bee species assemblages. We conclude that in order to fulfil the habitat requirements of bee species assemblages throughout the season, one should conserve and direct habitat restoration schemes towards increasing sun exposure at field edges with a diverse flora and a high proportion of semi-natural areas in the vicinity.     

Toll-Like Receptor 9-Activation during Onset of Myocardial Ischemia Does Not Influence Infarct Extension

Aim

Myocardial infarction (MI) remains a major cause of death and disability worldwide, despite available reperfusion therapies. Inflammatory signaling is considered nodal in defining final infarct size. Activation of the innate immune receptor toll-like receptors (TLR) 9 prior to ischemia and reperfusion (I/R) reduces infarct size, but the consequence of TLR9 activation timed to the onset of ischemia is not known.

Methods and Results

The TLR9-agonist; CpG B was injected i.p. in C57BL/6 mice immediately after induction of ischemia (30 minutes). Final infarct size, as well as area-at-risk, was measured after 24 hours of reperfusion. CpG B injection resulted in a significant increase in circulating granulocytes and monocytes both in sham and I/R mice. Paradoxically, clear evidence of reduced cardiac infiltration of both monocytes and granulocytes could be demonstrated in I/R mice treated with CpG B (immunocytochemistry, myeloperoxidase activity and mRNA expression patterns). In addition, systemic TLR9 activation elicited significant alterations of cardiac inflammatory genes. Despite these biochemical and cellular changes, there was no difference in infarct size between vehicle and CpG B treated I/R mice.

Conclusion

Systemic TLR9-stimulation upon onset of ischemia and subsequent reperfusion does not alter final infarct size despite causing clear alterations of both systemic and cardiac inflammatory parameters. Our results question the clinical usefulness of TLR9 activation during cardiac I/R.     

Soluble Urokinase Plasminogen Activator Receptor as a Marker for Use of Antidepressants

Objectives

Inflammation is involved in the pathogenesis of depression. A few cross-sectional population-based studies have found that depression is associated with increased levels of inflammatory markers. Soluble urokinase plasminogen activation receptor (suPAR) is known to be a stable marker for inflammation. We investigated the bidirectional association between suPAR levels and use of antidepressants.

Methods

suPAR level was measured in 9305 blood donors and analysed in relation to 5-years follow-up data on purchase of antidepressants and hospital diagnoses of depression from a nationwide Danish register.

Results

For men and women without prior use of antidepressants we found a significantly higher risk for incident use of antidepressants with higher suPAR values. For men, the risk of first use of antidepressants increased by 72% from the 1^st to the 4^th quartile (HR = 1.72, 95% CI: 1.11–2.69). For women, it increased by 108% from the 1^st to the 4^th quartile (HR = 2.08, 95% CI: 1.45–2.98). Previous use of antidepressants was also significantly associated with higher suPAR levels (p = 0.002).

Conclusions

High suPAR levels are associated with an increased risk for both previous and future use of antidepressants in healthy men and women. High suPAR are also associated with increased risk for a hospital diagnosis of depression.     

Evolution of interstitial Polychaeta (Annelida)

An update of the systematics is given for the eight most important interstitial polychaete families: Diurodrilidae, Nerillidae, Protodrilidae, Protodriloididae, Saccocirridae, Parergodrilidae, Polygordidae and Psammodrilidae. Additional information and new observations are presented for the Diurodrilidae, Nerillidae and Psammodrilidae. Three new supplementary evolutionary hypotheses for these families are here suggested: (I) basal position of Diurodrilidae in Polychaeta, (2) evolution of Nerillidae in mud, and (3) evolution from meio- to macrofaunal forms of Psammodrilidae.     

The iron-sulphur protein Ind1 is required for effective complex I assembly

NADH:ubiquinone oxidoreductase (complex I) of the mitochondrial inner membrane is a multi-subunit protein complex containing eight iron-sulphur (Fe-S) clusters. Little is known about the assembly of complex I and its Fe-S clusters. Here, we report the identification of a mitochondrial protein with a nucleotide-binding domain, named Ind1, that is required specifically for the effective assembly of complex I. Deletion of the IND1 open reading frame in the yeast Yarrowia lipolytica carrying an internal alternative NADH dehydrogenase resulted in slower growth and strongly decreased complex I activity, whereas the activities of other mitochondrial Fe-S enzymes, including aconitase and succinate dehydrogenase, were not affected. Two-dimensional gel electrophoresis, in vitro activity tests and electron paramagnetic resonance signals of Fe-S clusters showed that only a minor fraction (approximately 20%) of complex I was assembled in the ind1 deletion mutant. Using in vivo and in vitro approaches, we found that Ind1 can bind a [4Fe-4S] cluster that was readily transferred to an acceptor Fe-S protein. Our data suggest that Ind1 facilitates the assembly of Fe-S cofactors and subunits of complex I.     

NBP35 interacts with DRE2 in the maturation of cytosolic iron‐sulphur proteins in Arabidopsis thaliana

Proteins of the cytosolic pathway for iron‐sulphur (FeS) cluster assembly are conserved, except that plants lack a gene for CFD1 (Cytosolic FeS cluster Deficient 1). This poses the question of how NBP35 (Nucleotide‐Binding Protein 35 kDa), the heteromeric partner of CFD1 in metazoa, functions on its own in plants. Firstly, we created viable mutant alleles of NBP35 in Arabidopsis to overcome embryo lethality of previously reported knockout mutations. RNAi knockdown lines with less than 30% NBP35 protein surprisingly showed no developmental or biochemical differences to wild‐type. Substitution of Cys14 to Ala, which destabilized the N‐terminal Fe₄S₄ cluster in vitro, caused mild growth defects and a significant decrease in the activity of cytosolic FeS enzymes such as aconitase and aldehyde oxidases. The DNA glycosylase ROS1 was only partially decreased in activity and xanthine dehydrogenase not at all. Plants with strongly depleted NBP35 protein in combination with Cys14 to Ala substitution had distorted leaf development and decreased FeS enzyme activities. To find protein interaction partners of NBP35, a yeast‐two‐hybrid screen was carried out that identified NBP35 and DRE2 (Derepressed for Ribosomal protein S14 Expression). NBP35 is known to form a dimer, and DRE2 acts upstream in the cytosolic FeS protein assembly pathway. The NBP35–DRE2 interaction was not disrupted by Cys14 to Ala substitution. Our results show that NBP35 has a function in the maturation of FeS proteins that is conserved in plants, and is closely allied to the function of DRE2.     

Mapping of the epitope of a monoclonal antibody protecting plasminogen activator inhibitor-1 against inactivating agents.

Plasminogen activator inhibitor-1 (PAI-1) belongs to the serpin family of serine proteinase inhibitors. Serpins inhibit their target proteinases by an ester bond being formed between the active site serine of the proteinase and the P1 residue of the reactive centre loop (RCL) of the serpin, followed by insertion of the RCL into beta-sheet A of the serpin. Concomitantly, there are conformational changes in the flexible joint region lateral to beta-sheet A. We have now, by site-directed mutagenesis, mapped the epitope for a monoclonal antibody, which protects the inhibitory activity of PAI-1 against inactivation by a variety of agents acting on beta-sheet A and the flexible joint region. Curiously, the epitope is localized in alpha-helix C and the loop connecting alpha-helix I and beta-strand 5A, on the side of PAI-1 opposite to beta-sheet A and distantly from the flexible joint region. By a combination of site-directed mutagenesis and antibody protection against an inactivating organochemical ligand, we were able to identify a residue involved in conferring the antibody-induced conformational change from the epitope to the rest of the molecule. We have thus provided evidence for communication between secondary structural elements not previously known to interact in serpins.     

Palp morphology in two species of Prionospio (Polychaeta: Spionidae)

The palp morphology of Prionospio fallax Söderström, 1920 from Sweden and Prionospio cf. saldanha Day, 1961 from Thailand was examined with a scanning electron microscope. Prionospio fallax was also studied in vivo using light-microscopy. Both species have grooved feeding palps, adorned with up to five ciliary characters: frontal cilia, transverse ciliary bands (or bandlets), latero-frontal cirri, lateral cilia and randomly distributed non-motile cirri. All, except the frontal cilia and non-motile cirri, are asymmetrically arranged relative to the long axis of the palps. Prionospio fallax possesses transverse bandlets and the other four groups, while P. cf. saldanha has transverse bands (consisting of several contiguous bandlets), frontal cilia and some randomly scattered cirri. Asymmetrical palp ciliation was previously only known in Marenzelleria viridis (Verril, 1873) and the genus Scolelepis Blainville, 1828. The newly recognised transverse ciliary bands and bandlets are considered to be homologous with the transverse ciliary rows found basally on the palps of Paraprionospio pinnata (Ehlers, 1901). This multistate character (named transverse cilia) may prove useful in elucidating the phylogeny of the Prionospio-complex of genera.