The effectiveness of flower strips and hedgerows on pest control,pollination services and crop yield: a quantitative synthesis

Floral plantings are promoted to foster ecological intensification of agriculture through provisioning of ecosystem services. However, a comprehensive assessment of the effectiveness of different floral plantings, their characteristics and consequences for crop yield is lacking. Here we quantified the impacts of flower strips and hedgerows on pest control (18 studies) and pollination services (17 studies) in adjacent crops in North America, Europe and New Zealand. Flower strips, but not hedgerows, enhanced pest control services in adjacent fields by 16% on average. However, effects on crop pollination and yield were more variable. Our synthesis identifies several important drivers of variability in effectiveness of plantings: pollination services declined exponentially with distance from plantings, and perennial and older flower strips with higher flowering plant diversity enhanced pollination more effectively. These findings provide promising pathways to optimise floral plantings to more effectively contribute to ecosystem service delivery and ecological intensification of agriculture in the future.     

Nitrogen fixation and diversity of benthic cyanobacterial mats on coral reefs in Curaçao

Coral Reefs - Benthic cyanobacterial mats (BCMs) have increased in abundance on coral reefs worldwide. However, their species diversity and role in nitrogen fixation are poorly understood. We...     

Munc13-4 is essential for cytolytic granules fusion and is mutated in a form of familial hemophagocytic lymphohistiocytosis (FHL3)

Secretion of cytolytic granules content at the immunological synapse is a highly regulated process essential for lymphocyte cytotoxicity. This process requires the rapid transfer of perforin containing lytic granules to the target cell interface, followed by their docking and fusion with the plasma membrane. Defective cytotoxicity characterizes a genetically heterogeneous condition named familial hemophagocytic lymphohistiocytosis (FHL), which can be associated with perforin deficiency. The locus of a perforin (+) FHL subtype (FHL3), observed in 10 patients, was mapped to 17q25. This region contains hMunc13-4, a member of the Munc13 family of proteins involved in vesicle priming function. HMunc13-4 mutations were shown to cause FHL3. HMunc13-4 deficiency results in defective cytolytic granule exocytosis, despite polarization of the secretory granules and docking with the plasma membrane. Expressed tagged hMunc13-4 localizes with cytotoxic granules at the immunological synapse. HMunc13-4 is therefore essential for the priming step of cytolytic granules secretion preceding vesicle membrane fusion.     

Phylogenetic and molecular clock inferences of cyanobacterial strains within Rivulariaceae from distant environments

Heterocyst-forming cyanobacteria are important players at both evolutionary and ecological scales, but to date it has been difficult to establish their phylogenetic affiliations. We present data from a phylogenetic and molecular clock analysis of heterocystous cyanobacteria within the family Rivulariaceae, including the genera Calothrix, Rivularia, Gloeotrichia and Tolypothrix. The strains were isolated from distant geographic regions including fresh and brackish water bodies, microbial mats from beach rock, microbialites, pebble beaches, plus PCC strains 7103 and 7504. Phylogenetic inferences (distance, likelihood and Bayesian) suggested the monophyly of genera Calothrix and Rivularia. Molecular clock estimates indicate that Calothrix and Rivularia originated ～1500 million years ago (MYA) ago and species date back to 400-300 MYA while Tolypothrix and Gloeotrichia are younger genera (600-400 MYA).     

Analysis of Streptomyces coelicolor phosphopantetheinyl transferase, AcpS, reveals the basis for relaxed substrate specificity

The transfer of the phosphopantetheine chain from coenzyme A (CoA) to the acyl carrier protein (ACP), a key protein in both fatty acid and polyketide synthesis, is catalyzed by ACP synthase (AcpS). Streptomyces coelicolor AcpS is a doubly promiscuous enzyme capable of activation of ACPs from both fatty acid and polyketide synthesis and catalyzes the transfer of modified CoA substrates. Five crystal structures have been determined, including those of ligand-free AcpS, complexes with CoA and acetyl-CoA, and two of the active site mutants, His110Ala and Asp111Ala. All five structures are trimeric and provide further insight into the mechanism of catalysis, revealing the first detailed structure of a group I active site with the essential magnesium in place. Modeling of ACP binding supported by mutational analysis suggests an explanation for the promiscuity in terms of both ACP partner and modified CoA substrates.     

Decomposition ‘hotspots’ in a rewetted peatland: implications for water quality and carbon cycling

The hypothesis that specific components of seawater, such as particulate, dissolved and colloidal organic and inorganic material, render virions non-infective has long been postulated, but never rigorously tested. To address this hypothesis, the plaque assay method was used to derive infective decay rates, k, of two bacteriophages—P1 (marine host: PWH3a) and T4 (enteric host: E. coli B). We compared k values of bacteriophage suspended in serial filtrations of seawater, with and without autoclaving and UV oxidation. Both phages exhibited reduced decay rates in particle-free water (<0.2 μm) compared to <10 μm filtrate. The largest decrease in virion decay rates was achieved by autoclaving the 0.2 μm filtrate. UV oxidation of <0.2 μm filtrate, however, yielded higher decay rates than observed in autoclaved treatments. The lowest k values were seen in ultra-filtered seawater (<10 kDa). Exposure to a wide range of concentrations of Pronase E (a proteolytic enzyme), inorganic clay (kaolinite or montmorillonite), and organic particles (phytoplankton debris) did not promote phage inactivation. P1 infective titers were also not consistently reduced by exposures to axenic cultures of a resistant host mutant (PWH3a-R) and a non-host marine bacterium (MB-5). Finally, phage were exposed to a range of temperatures to derive activation energies required for phage inactivation. Application of the Arrhenius model to inactivation of T4 and P1 yielded activation energies (E _a) of 49 and 40 kJ mol⁻¹, respectively. This is the first comprehensive analysis in which specific seawater components were assayed for their ability to inactivate bacteriophage. Inactivation of these phage does not appear to depend on capsomere denaturation, proteolytic extracellular enzymes, sorption to non-host bacteria, clay particles or particulate organic debris, but is accelerated by naturally occurring particles, which include living organisms, and heat-labile colloids and macromolecules >10 kDa.     

Genetic variation on 9p22 is associated with abnormal ovarian ultrasound results in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial

Background

A recent ovarian cancer genome-wide association study (GWAS) identified a locus on 9p22 associated with reduced ovarian cancer risk. The single nucleotide polymorphism (SNP) markers localize to the BNC2 gene, which has been associated with ovarian development.

Methods

We analyzed the association of 9p22 SNPs with transvaginal ultrasound (TVU) screening results and CA-125 blood levels from participants without ovarian cancer in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO); 1,106 women with adequate ultrasound screening results and available genotyping information were included in the study.

Results

We observed a significantly increased risk of abnormal suspicious TVU results for seven SNPs on 9p22, with odds ratios between 1.68 (95% CI: 1.04–2.72) for rs4961501 and 2.10 (95% CI: 1.31–3.38) for rs12379183. Associations were restricted to abnormal suspicious findings at the first TVU screen. We did not observe an association between 9p22 SNPs and CA-125 levels.

Conclusions

Our findings suggest that 9p22 SNPs, which were found to be associated with decreased risk of ovarian cancer in a recent GWAS, are associated with sonographically detectable ovarian abnormalities. Our results corroborate the relevance of the 9p22 locus for ovarian biology. Further studies are required to understand the complex relationship between screening abnormalities and ovarian carcinogenesis and to evaluate whether this locus can influence the risk stratification of ovarian cancer screening.     

The use of quantitative imaging to investigate regulators of membrane trafficking in Arabidopsis stomatal closure

Expansion of gene families facilitates robustness and evolvability of biological processes but impedes functional genetic dissection of signalling pathways. To address this, quantitative analysis of single cell responses can help characterize the redundancy within gene families. We developed high‐throughput quantitative imaging of stomatal closure, a response of plant guard cells, and performed a reverse genetic screen in a group of Arabidopsis mutants to five stimuli. Focussing on the intersection between guard cell signalling and the endomembrane system, we identified eight clusters based on the mutant stomatal responses. Mutants generally affected in stomatal closure were mostly in genes encoding SNARE and SCAMP membrane regulators. By contrast, mutants in RAB5 GTPase genes played specific roles in stomatal closure to microbial but not drought stress. Together with timed quantitative imaging of endosomes revealing sequential patterns in FLS2 trafficking, our imaging pipeline can resolve non‐redundant functions of the RAB5 GTPase gene family. Finally, we provide a valuable image‐based tool to dissect guard cell responses and outline a genetic framework of stomatal closure.