Mineralogy and petrology of comet 81P/Wild 2 nucleus samples

The bulk of the comet 81P/Wild 2 (hereafter Wild 2) samples returned to Earth by the Stardust spacecraft appear to be weakly constructed mixtures of nanometer-scale grains, with occasional much larger (over 1 micrometer) ferromagnesian silicates, Fe-Ni sulfides, Fe-Ni metal, and accessory phases. The very wide range of olivine and low-Ca pyroxene compositions in comet Wild 2 requires a wide range of formation conditions, probably reflecting very different formation locations in the protoplanetary disk. The restricted compositional ranges of Fe-Ni sulfides, the wide range for silicates, and the absence of hydrous phases indicate that comet Wild 2 experienced little or no aqueous alteration. Less abundant Wild 2 materials include a refractory particle, whose presence appears to require radial transport in the early protoplanetary disk.     

Corridors increase plant species richness at large scales

Habitat fragmentation is one of the largest threats to biodiversity. Landscape corridors, which are hypothesized to reduce the negative consequences of fragmentation, have become common features of ecological management plans worldwide. Despite their popularity, there is little evidence documenting the effectiveness of corridors in preserving biodiversity at large scales. Using a large-scale replicated experiment, we showed that habitat patches connected by corridors retain more native plant species than do isolated patches, that this difference increases over time, and that corridors do not promote invasion by exotic species. Our results support the use of corridors in biodiversity conservation.     

SINGLE‐SHOT TURBO SPIN ECHO PULSE SEQUENCE FINDINGS IN DOGS WITH AND WITHOUT PROGRESSIVE MYELOMALACIA

Progressive myelomalacia is an uncommon type of ischemic, hemorrhagic spinal cord infarction. Diagnosis can be difficult, but prompt recognition is important. We hypothesized that cerebrospinal fluid signal attenuation on magnetic resonance (MR) images would be more extensive in dogs that developed progressive myelomalacia vs. control dogs. A retrospective analytic cohort study was designed. Dogs were included if they presented for acute paraplegia and loss of deep pain perception and had undergone MR imaging using both sagittal single‐shot turbo spin echo (SSTSE) and standard sagittal T2‐weighted fast spin echo (T2W) pulse sequences. Dogs were divided into progressive myelomalacia and control groups for comparisons. All MR examinations were evaluated by three reviewers blinded to patient outcome. Length of cerebrospinal fluid attenuation was recorded as a ratio to the length of the L2 vertebral body in SSTSE and T2W sequences (CSF:L2_SSTSE and CSF:L2_T2, respectively). Length of intramedullary spinal cord hyperintensity was recorded as a ratio to the length of the L2 vertebral body in T2W sequences. A total of 21 dogs were included (five in the progressive myelomalacia group and 16 in the control group). The mean CSF:L2_SSTSE attenuation value was significantly higher in dogs that developed progressive myelomalacia (CSF:L2_SSTSE = 10.7) compared to controls (CSF:L2_SSTSE = 5.4; P = 0.015). A cut off ratio of attenuation >7.4 provided optimal differentiation between groups in this study. Findings supported the conclusion that dogs with CSF:L2_SSTSE ≤ 7.4 are unlikely to develop progressive myelomalacia while dogs with CSF:L2_SSTSE > 7.4 are indeterminate for progressive myelomalacia.     

Nutritional potential of fodder trees on clay and sandy soils

In this paper we focus on the functional role of trees for livestock as fodder in silvopastoral systems, available for (dairy) cows within or around pastures. Farmers often report that cows browse from trees, however, little is known about the nutritional value of different tree species. Therefore, the objective of this study was to assess the effect of soil type and season on the nutritional potential of leaves from Fraxinus excelsior, Alnus glutinosa and Salix viminalis. Leaf samples were collected at 10 sites in the Netherlands on clay and on sandy soils in June, July and September and were analysed for digestibility, crude protein, macro and micro element concentrations. We conclude that the nutritional value of tree leaves differs between the studied tree species. Regarding the seasonal variation, we found a main effect of sampling period on the crude protein, calcium, phosphorus, copper and selenium concentration of leaves. No main effect of soil type was found on the nutritional value of leaves. Significant interactions were found for species × sampling period (digestibility, calcium, sulphur) and species × soil (digestibility, calcium). For the zinc and selenium concentration in tree leaves, a significant species × soil × sampling period interaction was found. We conclude that trees can play a role for supplying protein, and macro and micro elements to livestock, but that it depends on which tree species is used.     

Characterization of the mechanism of action of the fungicide fenpicoxamid and its metabolite UK‐2A

BACKGROUND

Fenpicoxamid is a new fungicide for control of Zymoseptoria tritici, and is a derivative of the natural product UK‐2A. Its mode of action and target site interactions have been investigated.

RESULTS

UK‐2A strongly inhibited cytochrome c reductase, whereas fenpicoxamid was much less active, consistent with UK‐2A being the fungicidally active species generated from fenpicoxamid by metabolism. Both compounds caused rapid loss of mitochondrial membrane potential in Z. tritici spores. In Saccharomyces cerevisiae, amino acid substitutions N31K, G37C and L198F at the Qi quinone binding site of cytochrome b reduced sensitivity to fenpicoxamid, UK‐2A and antimycin A. Activity of fenpicoxamid was not reduced by the G143A exchange responsible for strobilurin resistance. A docking pose for UK‐2A at the Qi site overlaid that of antimycin A. Activity towards Botrytis cinerea was potentiated by salicylhydroxamic acid, showing an ability of alternative respiration to mitigate activity. Fungitoxicity assays against Z. tritici field isolates showed no cross‐resistance to strobilurin, azole or benzimidazole fungicides.

CONCLUSION

Fenpicoxamid is a Qi inhibitor fungicide that provides a new mode of action for Z. tritici control. Mutational and modeling studies suggest that the active species UK‐2A binds at the Qi site in a similar, but not identical, fashion to antimycin A. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Yersinia pestis: examining wildlife plague surveillance in China and the USA

Plague is a zoonotic disease caused by the bacterium Yersinia pestis Lehmann and Neumann, 1896. Although it is essentially a disease of rodents, plague can also be transmitted to people. Historically, plague has caused massive morbidity and mortality events in human populations, and has recently been classified as a reemerging disease in many parts of the world. This public health threat has led many countries to set up wild and domestic animal surveillance programs in an attempt to monitor plague activity that could potentially spill over into human populations. Both China and the USA have plague surveillance programs in place, but the disease dynamics differ in each country. We present data on plague seroprevalence in wildlife and review different approaches for plague surveillance in the 2 countries. The need to better comprehend plague dynamics, combined with the fact that there are still several thousand human plague cases per year, make well-designed wildlife surveillance programs a critical part of both understanding plague risks to humans and preventing disease outbreaks in the future.