The MrCYP52 Cytochrome P450 Monoxygenase Gene of Metarhizium robertsii Is Important for Utilizing Insect Epicuticular Hydrocarbons

Fungal pathogens of plants and insects infect their hosts by direct penetration of the cuticle. Plant and insect cuticles are covered by a hydrocarbon-rich waxy outer layer that represents the first barrier against infection. However, the fungal genes that underlie insect waxy layer degradation have received little attention. Here we characterize the single cytochrome P450 monoxygenase family 52 (MrCYP52) gene of the insect pathogen Metarhizium robertsii, and demonstrate that it encodes an enzyme required for efficient utilization of host hydrocarbons. Expressing a green florescent protein gene under control of the MrCYP52 promoter confirmed that MrCYP52 is up regulated on insect cuticle as well as by artificial media containing decane (C10), extracted cuticle hydrocarbons, and to a lesser extent long chain alkanes. Disrupting MrCYP52 resulted in reduced growth on epicuticular hydrocarbons and delayed developmental processes on insect cuticle, including germination and production of appressoria (infection structures). Extraction of alkanes from cuticle prevented induction of MrCYP52 and reduced growth. Insect bioassays against caterpillars (Galleria mellonella) confirmed that disruption of MrCYP52 significantly reduces virulence. However, MrCYP52 was dispensable for normal germination and appressorial formation in vitro when the fungus was supplied with nitrogenous nutrients. We conclude therefore that MrCYP52 mediates degradation of epicuticular hydrocarbons and these are an important nutrient source, but not a source of chemical signals that trigger infection processes

Genomic perspectives on the evolution of fungal entomopathogenicity in Beauveria bassiana

The ascomycete fungus Beauveria bassiana is a pathogen of hundreds of insect species and is commercially produced as an environmentally friendly mycoinsecticide. We sequenced the genome of B. bassiana and a phylogenomic analysis confirmed that ascomycete entomopathogenicity is polyphyletic, but also revealed convergent evolution to insect pathogenicity. We also found many species-specific virulence genes and gene family expansions and contractions that correlate with host ranges and pathogenic strategies. These include B. bassiana having many more bacterial-like toxins (suggesting an unsuspected potential for oral toxicity) and effector-type proteins. The genome also revealed that B. bassiana resembles the closely related Cordyceps militaris in being heterothallic, although its sexual stage is rarely observed. A high throughput RNA-seq transcriptomic analysis revealed that B. bassiana could sense and adapt to different environmental niches by activating well-defined gene sets. The information from this study will facilitate further development of B. bassiana as a cost-effective mycoinsecticide

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

GWTC-2.1: Deep extended catalog of compact binary coalescences observed by LIGO and Virgo during the first half of the third observing run

The second Gravitational-Wave Transient Catalog, GWTC-2, reported on 39 compact binary coalescences observed by the Advanced LIGO and Advanced Virgo detectors between 1 April 2019 15:00 UTC and 1 October 2019 15:00 UTC. Here, we present GWTC-2.1, which reports on a deeper list of candidate events observed over the same period. We analyze the final version of the strain data over this period with improved calibration and better subtraction of excess noise, which has been publicly released. We employ three matched-filter search pipelines for candidate identification, and estimate the probability of astrophysical origin for each candidate event. While GWTC-2 used a false alarm rate threshold of 2 per year, we include in GWTC-2.1, 1201 candidates that pass a false alarm rate threshold of 2 per day. We calculate the source properties of a subset of 44 high-significance candidates that have a probability of astrophysical origin greater than 0.5. Of these candidates, 36 have been reported in GWTC-2. We also calculate updated source properties for all binary block hole events previously reported in GWTC-1. If the 8 additional high-significance candidates presented here are astrophysical, the mass range of events that are unambiguously identified as binary black holes (both objects \geq 3M_\odot) is increased compared to GWTC-2, with total masses from \sim 14M_\odot for GW190924_021846 to \sim 182M_\odot for GW190426_190642. Source properties calculated using our default prior suggest that the primary components of two new candidate events (GW190403_051519 and GW190426_190642) fall in the mass gap predicted by pair-instability supernova theory. We also expand the population of binaries with significantly asymmetric mass ratios reported in GWTC-2 by an additional two events (the mass ratio is less than 0.65 and 0.44 at 90% probability for GW190403_051519 and GW190917_114630 respectively), and find that 2 of the 8 new events have effective inspiral spins \chi_\mathrm{eff} > 0 (at 90\% credibility), while no binary is consistent with \chi_\mathrm{eff} \lt 0 at the same significance. We provide updated estimates for rates of binary black hole and binary neutron star coalescence in the local Universe

Multi-messenger Observations of a Binary Neutron Star Merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ∼ 1.7 {{s}} with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of {40}-8+8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 {M}ȯ . An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ∼ 40 {{Mpc}}) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ∼10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ∼ 9 and ∼ 16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta.</p

Monitoring water bodies over whole Africa at 250 m resolution : multi-annual analysis of various spatio-temporal dynamics

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Monitoring water bodies over whole Africa in near real time : detection algorithms and preliminary results

Detecting water bodies in nearly real time over the whole Africa is a challenge addressed by the Geoland-2 project (GMES). This information was found critical by end-users for natural resource management as well as for environmental monitoring. Non-permanent water bodies dynamic is also expected to be affected by climate change and requires appropriate system development for operational monitoring. In the framework of Geoland-2 project, a water bodies detection algorithm has been developed in two version. The Version1 (1km of spatial resolution) is the result of combination of three existing products in order to have the best information available. The Version2 (250m of spatial resolution) is the detection result of a method based on a standardized multispectral transformation (developed by Pekel et al., 2010), the new algorithm is suited to detect the water occurrence in various ecological conditions and appears to be more generic than classification approaches. Implementation of this algorithm allowed processing multi-year 250 m surface reflectance time series acquired by the MODIS instruments. Both versions are designed to be operational in nearly real time and to be externally validaded