A comparison of the strength of biodiversity effects across multiple functions

In order to predict which ecosystem functions are most at risk from biodiversity loss, meta-analyses have generalised results from biodiversity experiments over different sites and ecosystem types. In contrast, comparing the strength of biodiversity effects across a large number of ecosystem processes measured in a single experiment permits more direct comparisons. Here, we present an analysis of 418 separate measures of 38 ecosystem processes. Overall, 45 % of processes were significantly affected by plant species richness, suggesting that, while diversity affects a large number of processes not all respond to biodiversity. We therefore compared the strength of plant diversity effects between different categories of ecosystem processes, grouping processes according to the year of measurement, their biogeochemical cycle, trophic level and compartment (above- or belowground) and according to whether they were measures of biodiversity or other ecosystem processes, biotic or abiotic and static or dynamic. Overall, and for several individual processes, we found that biodiversity effects became stronger over time. Measures of the carbon cycle were also affected more strongly by plant species richness than were the measures associated with the nitrogen cycle. Further, we found greater plant species richness effects on measures of biodiversity than on other processes. The differential effects of plant diversity on the various types of ecosystem processes indicate that future research and political effort should shift from a general debate about whether biodiversity loss impairs ecosystem functions to focussing on the specific functions of interest and ways to preserve them individually or in combination.     

High gene flow in two thrips‐pollinated South‐East Asian pioneer trees: genetic diversity and population structure of Macaranga hypoleuca and M. beccariana (Euphorbiaceae)

As a result of intensive exploitation, disturbed forests now dominate large areas of lowland tropical rainforest in South‐East Asia. The genus Macaranga comprises some of the most important pioneer tree species of the region, among them M. beccariana and M. hypoleuca, two closely related obligate ant‐plants pollinated by thrips. We used nuclear and plastid DNA markers to address questions of genetic diversity and population structure. Twelve plastid haplotypes were detected among 281 samples, three of which were shared between the two study species. Hybrids between the two species appear to be rare. Overall, genetic diversity in both species was moderate to high, with low levels of population differentiation, consistent with other tropical pioneer trees. Genetic structure was generally more pronounced in plastid than in nuclear data, indicating that gene flow via pollen may be more efficient than via seeds. Thrips apparently also serve as efficient pollinators over long distances, perhaps through a combination of passive dispersal by wind and active search for inflorescences in the target area. Our results indicate that M. beccariana and M. hypoleuca populations from recently disturbed habitats do not yet suffer from reduced genetic diversity or increased inbreeding. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 173 , 606–621.     

Modes of Biomineralization of Magnetite by Microbes

Biomineralization processes have traditionally been grouped into two distinct modes; biologically induced mineralization (BIM) and biologically controlled mineralization (BCM). In BIM, microbes cause mineral formation by sorbing solutes onto their cell surfaces or extruded organic polymers and/or releasing reactive metabolites which alter the saturation state of the solution proximal to the cell or polymer surface. Such mineral products appear to have no specific recognized functions. On the other hand, in BCM microbes exert a great degree of chemical and genetic control over the nucleation and growth of mineral particles, presumably because the biominerals produced serve some physiological function. Interestingly, there are examples where the same biomineral is produced by both modes in the same sedimentary environment. For example, the magnetic mineral magnetite (Fe ₃ O ₄ ) is generated extracellularly in the bulk pore waters of sediments by various Fe(III)-reducing bacteria under anaerobic conditions, while some other anaerobic and microaerophilic bacteria and possibly protists form magnetite intracellularly within preformed vesicles. Differences in precipitation mechanisms might be caused by enzymatic activity at specific sites on the surface of the cell. Whereas one type of microbe might facilitate the transport of dissolved Fe(III) into the cell, another type will express its reductive enzymes and cause the reduction of Fe(III) external to the cell. Still other microbes might induce magnetite formation indirectly through the oxidation of Fe(II), followed by the reaction of dissolved Fe(II) with hydrolyzed Fe(III). The biomineralization of magnetite has significant effect on environmental iron cycling, the magnetization of sediments and thus the geologic record, and on the use of biomarkers as microbial fossils.     

The Formation and Preservation of Synechococcus elongatus Cell Molds in Simulated Silica Sinter: Implications for the Identification of Microfossils

Siliceous sinters that precipitate around modern hot spring systems are able to fossilize the indigenous microbial communities, forming molds that accurately outline the shape of the microorganisms. Over time, the biomass decays, and only silica molds or their infill may remain as evidence of the former living cells. However, little is known regarding the fidelity of such silica molds in terms of size and morphology, and the preservation of critical parameters for the identification of ancient silicified microorganisms by silica molds remains untested. Here we report experiments examining the formation of microbial molds of the cyanobacterium Synechococcus elongatus in silica gel. We demonstrate that post-depositional processes, primarily desiccation, are crucial for obtaining accurate and robust molds, and that initial desiccation acts to strengthen cell molds against further alteration. However, all silica gel treatments systematically created preservational biases (changes in size, additional structures) that may be misleading and may complicate the identification of fossil microorganisms.     

Structure–activity relationships of 6-(aminomethylphenoxy)-benzoxaborole derivatives as anti-inflammatory agent

A series of novel 6-(aminomethylphenoxy)benzoxaborole analogs was synthesized for the investigation of the structure–activity relationship of the inhibition of TNF-alpha, IL-1beta, and IL-6, from lipopolysaccharide stimulated peripheral blood mononuclear cells. Compounds 9d and 9e showed potent activity against all three cytokines with IC₅₀ values between 33 and 83 nM. Chloro substituted analog 9e (AN3485) is considered to be a promising lead for novel anti-inflammatory agent with a favorable pharmacokinetic profile.     

Discovery and structure–activity relationships of 6-(benzoylamino)benzoxaboroles as orally active anti-inflammatory agents

Structure–activity relationships of 6-(benzoylamino)benzoxaborole analogs were investigated for the inhibition of TNF-α, IL-1β, and IL-6 from lipopolysaccharide stimulated peripheral blood mononuclear cells. Compound 1q showed potent activity against all three cytokines with IC₅₀ values between 0.19 and 0.50 μM, inhibited LPS-induced TNF-α and IL-6 elevation in mice and improved collagen-induced arthritis in mice. Compound 1q (AN4161) is considered to be a promising lead for novel anti-inflammatory agent with an excellent pharmacokinetic profile.     

Optimization of potent and selective dual mTORC1 and mTORC2 inhibitors: The discovery of AZD8055 and AZD2014

The optimization of a potent and highly selective series of dual mTORC1 and mTORC2 inhibitors is described. An initial focus on improving cellular potency whilst maintaining or improving other key parameters, such as aqueous solubility and margins over hERG IC₅₀, led to the discovery of the clinical candidate AZD8055 (14). Further optimization, particularly aimed at reducing the rate of metabolism in human hepatocyte incubations, resulted in the discovery of the clinical candidate AZD2014 (21).     

Linear fusigen as the major hydroxamate siderophore of the ectomycorrhizal Basidiomycota Laccaria laccata and Laccaria bicolor

A screening for siderophores produced by the ectomycorrhizal fungi Laccaria laccata and Laccaria bicolor in synthetic low iron medium revealed the release of several different hydroxamate siderophores of which four major siderophores could be identified by high resolution mass spectrometry. While ferricrocin, coprogen and triacetylfusarinine C were assigned as well as other known fungal siderophores, a major peak of the siderophore mixture revealed an average molecular mass of 797 for the iron-loaded compound. High resolution mass spectrometry indicated an absolute mass of m/z = 798.30973 ([M + H]⁺). With a relative error of Δ = 0.56 ppm this corresponds to linear fusigen (C₃₃H₅₂N₆O₁₃Fe; MW = 797.3). The production of large amounts of linear fusigen by these basidiomycetous mycorrhizal fungi may possibly explain the observed suppression of plant pathogenic Fusarium species. For comparative purposes Fusarium roseum was included in this study as a well known producer of cyclic and linear fusigen.     

An enzyme-linked immunosorbent assay for detection of avian influenza virus subtypes H5 and H7 antibodies

Background

Avian influenza virus (AIV) subtypes H5 and H7 attracts particular attention because of the risk of their potential pathogenicity in poultry. The haemagglutination inhibition (HI) test is widely used as subtype specific test for serological diagnostics despite the laborious nature of this method. However, enzyme-linked immunosorbent assays (ELISAs) are being explored as an alternative test method.H5 and H7 specific monoclonal antibodies were experimentally raised and used in the development of inhibition ELISAs for detection of serological response specifically directed against AIV subtypes H5 and H7. The ELISAs were evaluated with polyclonal chicken anti-AIV antibodies against AIV subtypes: H1N2, H5N2, H5N7, H7N1, H7N7, H9N9, H10N4 and H16N3.

Results

Both the H5 and H7 ELISA proved to have a high sensitivity and specificity and the ELISAs detected H5 and H7 antibodies earlier during experimental infection than the HI test did. The reproducibility of the ELISA’s performed at different times was high with Pearson correlation coefficients of 0.96-0.98.

Conclusions

The ELISAs are a potential alternative to the HI test for screening of large amounts of avian sera, although only experimental sera were tested in this study.