Co-occurrence of antibiotic,biocide, and heavy metal resistance genes in bacteria from metal and radionuclide contaminated soils at the Savannah River Site

Contaminants such as heavy metals may contribute to the dissemination of antimicrobial resistance (AMR) by enriching resistance gene determinants via co-selection mechanisms. In the present study, a survey was performed on soils collected from four areas at the Savannah River Site (SRS), South Carolina, USA, with varying contaminant profiles: relatively pristine (Upper Three Runs), heavy metals (Ash Basins), radionuclides (Pond B) and heavy metal and radionuclides (Tim’s Branch). Using 16S rRNA gene amplicon sequencing, we explored the structure and diversity of soil bacterial communities. Sites with legacies of metal and/or radionuclide contamination displayed significantly lower bacterial diversity compared to the reference site. Metagenomic analysis indicated that multidrug and vancomycin antibiotic resistance genes (ARGs) and metal resistance genes (MRGs) including those associated with copper, arsenic, iron, nickel and zinc were prominent in all soils including the reference site. However, significant differences were found in the relative abundance and diversity of certain ARGs and MRGs in soils with metal/radionuclide contaminated soils compared to the reference site. Co-occurrence patterns revealed significant ARG/MRG subtypes in predominant soil taxa including Acidobacteriaceae, Bradyrhizobium, Mycobacterium, Streptomyces, Verrumicrobium, Actinomadura and Solirubacterales. Overall, the study emphasizes the potential risk of human activities on the dissemination of AMR in the environment.     

Evaluation of non-target effects of OMRI-listed insecticides for management of Drosophila suzukii Matsumura in berry crops

The spotted wing drosophila, Drosophila suzukii Matsumura, is an invasive pest of many fruit crops throughout North America, South America and Europe. The presence of this destructive pest has led to an increase in the number of insecticide applications. While conventional growers have an arsenal of different insecticides at their disposal, organic growers have a limited selection of effective options and rely heavily on applications of Entrust^®, the organic formulation of spinosad. An important part of research is to develop more tools for organic growers and evaluate the effects of insecticides intended to target D. suzukii on natural enemies in the system. The effects of six organic pesticides alone and in combination with three adjuvants and two phagostimulants were tested in laboratory bioassays on three common natural enemies in berry production systems including two predators, Chrysoperla rufilabris and Orius insidiosus, and a parasitoid wasp, Aphidius colemani. Under the IOBC toxicity rating scale, spinosad was rated consistently from slightly harmful to harmful across natural enemy species and residue age (the effects of pesticides over time). Sabadilla alkaloids caused mortality to O. insidiosus equal to that of spinosad. All tested pesticides were at least slightly harmful to A. colemani, and the adjuvant polyether-polymethylsiloxane-copolymer polyether caused mortality that was not significantly different from spinosad. In general, neither the addition of adjuvants nor phagostimulants increased the mortality of the insecticides tested. The exception was polyether-polymethylsiloxane-copolymer polyether, but it is unclear whether it increased the toxicity of the pesticides or was simply toxic itself since it caused high mortality to A. colemani when applied alone. Sublethal effects were measured for two predatory species by measuring eggs laid and % egg hatch. Minimal sublethal effects were observed in C. rufilabris. In contrast, all tested insecticides caused reduced egg hatch in O. insidiosus compared with the control.     

How Well Do Computer-Generated Faces Tap Face Expertise?

The use of computer-generated (CG) stimuli in face processing research is proliferating due to the ease with which faces can be generated, standardised and manipulated. However there has been surprisingly little research into whether CG faces are processed in the same way as photographs of real faces. The present study assessed how well CG faces tap face identity expertise by investigating whether two indicators of face expertise are reduced for CG faces when compared to face photographs. These indicators were accuracy for identification of own-race faces and the other-race effect (ORE)–the well-established finding that own-race faces are recognised more accurately than other-race faces. In Experiment 1 Caucasian and Asian participants completed a recognition memory task for own- and other-race real and CG faces. Overall accuracy for own-race faces was dramatically reduced for CG compared to real faces and the ORE was significantly and substantially attenuated for CG faces. Experiment 2 investigated perceptual discrimination for own- and other-race real and CG faces with Caucasian and Asian participants. Here again, accuracy for own-race faces was significantly reduced for CG compared to real faces. However the ORE was not affected by format. Together these results signal that CG faces of the type tested here do not fully tap face expertise. Technological advancement may, in the future, produce CG faces that are equivalent to real photographs. Until then caution is advised when interpreting results obtained using CG faces.     

Evidence for bias in estimates of local genetic structure due to sampling scheme

Traditional population genetic analyses typically seek to characterize the genetic substructure caused by the nonrandom distribution of individuals. However, the genetic structuring of adult populations often does not remain constant over time, and may vary relative to season or life-history stages. Estimates of genetic structure may be biased if samples are collected at a single point in time, and will reflect the social organization of the species at the time the samples were collected. The complex population structures exhibited by many migratory species, where temporal shifts in social organization correspond to a large-scale shift in geographic distribution, serve as examples of the importance that time of sampling can have on estimates of genetic structure. However, it is often fine-scale genetic structure that is crucial for defining practical units for conservation and management and it is at this scale that distributional shifts of organisms relative to the timing of sampling may have a profound yet unrecognized impact on our ability to interpret genetic data. In this study, we used the wild turkey to investigate the effects of sampling regime on estimates of genetic structure at local scales. Using mitochondrial sequence data, nuclear microsatellite data and allozyme data, we found significant genetic structuring among localized winter flocks of wild turkeys. Conversely, we found no evidence for genetic structure among sampling locations during the spring, when wild turkeys exist in mixed assemblages of genetically differentiated winter flocks. If the lack of detectable genetic structure among individuals is due to an admixture of social units as in the case of wild turkeys during the spring, then the F _IS value rather than the F _ST value may be the more informative statistic in regard to the levels of genetic structure among population subunits.     

AMP-activated Protein Kinase Attenuates Nitric Oxide-induced ��-Cell Death

During the initial autoimmune response in type 1 diabetes, islets are exposed to a damaging mix of pro-inflammatory molecules that stimulate the production of nitric oxide by β-cells. Nitric oxide causes extensive but reversible cellular damage. In response to nitric oxide, the cell activates pathways for functional recovery and adaptation as well as pathways that direct β-cell death. The molecular events that dictate cellular fate following nitric oxide-induced damage are currently unknown. In this study, we provide evidence that AMPK plays a primary role controlling the response of β-cells to nitric oxide-induced damage. AMPK is transiently activated by nitric oxide in insulinoma cells and rat islets following IL-1 treatment or by the exogenous addition of nitric oxide. Active AMPK promotes the functional recovery of β-cell oxidative metabolism and abrogates the induction of pathways that mediate cell death such as caspase-3 activation following exposure to nitric oxide. Overall, these data show that nitric oxide activates AMPK and that active AMPK suppresses apoptotic signaling allowing the β-cell to recover from nitric oxide-mediated cellular stress.     

Inhibition of Thrombin Formation by Active Site Mutated (S360A) Activated Protein C

Activated protein C (APC) down-regulates thrombin formation through proteolytic inactivation of factor Va (FVa) by cleavage at Arg⁵⁰⁶ and Arg³⁰⁶ and of factor VIIIa (FVIIIa) by cleavage at Arg³³⁶ and Arg⁵⁶². To study substrate recognition by APC, active site-mutated APC (APC(S360A)) was used, which lacks proteolytic activity but exhibits anticoagulant activity. Experiments in model systems and in plasma show that APC(S360A), and not its zymogen protein C(S360A), expresses anticoagulant activities by competing with activated coagulation factors X and IX for binding to FVa and FVIIIa, respectively. APC(S360A) bound to FVa with a K_D of 0.11 ± 0.05 nm and competed with active site-labeled Oregon Green activated coagulation factor X for binding to FVa. The binding of APC(S360A) to FVa was not affected by protein S but was inhibited by prothrombin. APC(S360A) binding to FVa was critically dependent upon the presence of Arg⁵⁰⁶ and not Arg³⁰⁶ and additionally required an active site accessible to substrates. Inhibition of FVIIIa activity by APC(S360A) was >100-fold less efficient than inhibition of FVa. Our results show that despite exosite interactions near the Arg⁵⁰⁶ cleavage site, binding of APC(S360A) to FVa is almost completely dependent on Arg⁵⁰⁶ interacting with APC(S360A) to form a nonproductive Michaelis complex. Because docking of APC to FVa and FVIIIa constitutes the first step in the inactivation of the cofactors, we hypothesize that the observed anticoagulant activity may be important for in vivo regulation of thrombin formation.     

Trp2313-His2315 of Factor VIII C2 Domain Is Involved in Membrane Binding: STRUCTURE OF A COMPLEX BETWEEN THE C2 DOMAIN AND AN INHIBITOR OF MEMBRANE BINDING*

Factor VIII (FVIII) plays a critical role in blood coagulation by forming the tenase complex with factor IXa and calcium ions on a membrane surface containing negatively charged phospholipids. The tenase complex activates factor X during blood coagulation. The carboxyl-terminal C2 domain of FVIII is the main membrane-binding and von Willebrand factor-binding region of the protein. Mutations of FVIII cause hemophilia A, whereas elevation of FVIII activity is a risk factor for thromboembolic diseases. The C2 domain-membrane interaction has been proposed as a target of intervention for regulation of blood coagulation. A number of molecules that interrupt FVIII or factor V (FV) binding to cell membranes have been identified through high throughput screening or structure-based design. We report crystal structures of the FVIII C2 domain under three new crystallization conditions, and a high resolution (1.15 Å) crystal structure of the FVIII C2 domain bound to a small molecular inhibitor. The latter structure shows that the inhibitor binds to the surface of an exposed β-strand of the C2 domain, Trp²³¹³-His²³¹⁵. This result indicates that the Trp²³¹³-His²³¹⁵ segment is an important constituent of the membrane-binding motif and provides a model to understand the molecular mechanism of the C2 domain membrane interaction.