Detection of Predation Using qPCR: Effect of Prey Quantity, Elapsed Time, Chaser Diet, and Sample Preservation on Detectable Quantity of Prey DNA

Using quantitative PCR that amplified a prey-specific mtDNA 214 bp amplicon from the COI mitochondrial gene of the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), prey eggs of known age and number were fed to larvae of the generalist predator lady beetle Coleomegilla maculata (De Geer) (Coleoptera: Coccinellidae), to elucidate the effects of time and diet since consumption, number of prey eggs, and methods for sample fixation and preservation, on the quantity of target DNA detected. Signal was strongly attenuated directly after cessation of feeding, even when predators were immediately frozen at -20°C. However, the quantity of target detected was significantly related to the number of eggs consumed and the time elapsed since eating. Decrease in detected prey DNA was consistent with a negative exponential model. The target DNA sequence disappeared from starved predators (quantitative half-life estimate of 59 min) more slowly than those fed potato aphids after consuming the target prey eggs (half-life estimate 16 min), whereas those fed C. maculata eggs as a chaser were intermediate in the rate at which they degraded the target prey DNA sequence. Fixative protocols are of critical importance in proper use of the qPCR technique. Among seven methods tested, storing the predator immediately in 70% ethanol prechilled to -20°C yielded the highest amount of target sequence, 22.8% of that recovered directly from a single intact prey egg. Samples frozen without solvent at -80°C and -20°C yielded only 6.0% and 2.3% of the target DNA respectively, and room temperature ethanol and ethylene glycol-based antifreeze averaged below 1% recovery of target DNA. Nevertheless, target prey was detected in more than 80% of antifreeze-stored predators. Predators killed and held at room temperature for 4 h or 5 days yielded no target prey DNA in 18 of 20 cases. These results emphasize both the value and the complexities of application of the qPCR technique to field predation studies

Hoplia equina (Coleoptera: Scarabaeidae) and Nontarget Capture Using 2-Tetradecanone-Baited Traps

Using bucket traps baited with 2-tetradecanone, the sex pheromone of Hoplia equina LeConte, an important pest of cranberries in Massachusetts, we investigated the effect of trap height, color, pheromone load, and lure aging on male capture, as well as captures of nontarget arthropods including pollinators. Male capture was inversely related to height of traps over the four heights tested (0, 20, 60, and 100 cm). Captures increased with increasing pheromone load over the doses of 0, 100, 300, and 600 μg, but captures at the highest load, 1,000 μg, were not significantly different from 300 or 600 μg. H. equina captures were strongly diurnal, with a flight period spanning ≈6 wk starting in mid-June. Vane color of traps (white, yellow, green, blue, red, black) did not affect H. equina capture but significantly influenced capture of nontargets, including pollinators. A bucket trap with the funnel opening at 20 cm, and green (or red) vanes, baited with 600 μg of 2-tetradecanone, was the optimal design for high male capture and low nontarget capture. The low-cost capture of over 50,000 H. equina on a 2.4-ha commercial bog in Massachusetts with this lure-trap combination indicates the feasibility of mass trapping for managing established infestations of H. equin

Lateralization of mesial temporal lobe epilepsy with chronic ambulatory electrocorticography

Objective Patients with suspected mesial temporal lobe (MTL) epilepsy typically undergo inpatient video–electroencephalography (EEG) monitoring with scalp and/or intracranial electrodes for 1 to 2 weeks to localize and lateralize the seizure focus or foci. Chronic ambulatory electrocorticography (ECoG) in patients with MTL epilepsy may provide additional information about seizure lateralization. This analysis describes data obtained from chronic ambulatory ECoG in patients with suspected bilateral MTL epilepsy in order to assess the time required to determine the seizure lateralization and whether this information could influence treatment decisions. Methods Ambulatory ECoG was reviewed in patients with suspected bilateral MTL epilepsy who were among a larger cohort with intractable epilepsy participating in a randomized controlled trial of responsive neurostimulation. Subjects were implanted with bilateral MTL leads and a cranially implanted neurostimulator programmed to detect abnormal interictal and ictal ECoG activity. ECoG data stored by the neurostimulator were reviewed to determine the lateralization of electrographic seizures and the interval of time until independent bilateral MTL electrographic seizures were recorded. Results Eighty-two subjects were implanted with bilateral MTL leads and followed for 4.7 years on average (median 4.9 years). Independent bilateral MTL electrographic seizures were recorded in 84%. The average time to record bilateral electrographic seizures in the ambulatory setting was 41.6 days (median 13 days, range 0–376 days). Sixteen percent had only unilateral electrographic seizures after an average of 4.6 years of recording. Significance About one third of the subjects implanted with bilateral MTL electrodes required \u3e1 month of chronic ambulatory ECoG before the first contralateral MTL electrographic seizure was recorded. Some patients with suspected bilateral MTL seizures had only unilateral electrographic seizures. Chronic ambulatory ECoG in patients with suspected bilateral MTL seizures provides data in a naturalistic setting, may complement data from inpatient video-EEG monitoring, and can contribute to treatment decisions. Key Points Ambulatory electrocorticograms were obtained in patients implanted with a responsive neurostimulator and bilateral mesial temporal intracranial electrodes. In patients with bilateral seizures, the average time to record bilateral electrographic seizures in the ambulatory setting was 41.6 days (median 13, range 0–376). Some patients suspected to have bilateral MTL seizures after standard diagnostic localization evaluations had only unilateral electrographic seizures. Chronic ambulatory ECoG samples provide naturalistic data that complement inpatient monitoring, and may contribute information that affects treatment decisions

The mechanism of the amidases: mutating the glutamate adjacent to the catalytic triad inactivates the enzyme due to substrate mispositioning

All known nitrilase superfamily amidase and carbamoylase structures have an additional glutamate thatis hydrogen bonded to the catalytic lysine in addition to the Glu, Lys, Cys “catalytic triad.” In the amidase from Geobacillus pallidus, mutating this glutamate (Glu-142) to a leucine or aspartate renders the enzyme inactive. X-ray crystal structure determination shows that the structural integrity of the enzymeismaintained despite themutation with the catalytic cysteine (Cys-166), lysine (Lys-134), and glutamate (Glu- 59)in positions similar to those of the wild-type enzyme. In the case of the E142L mutant, a chloride ion is located in the position occupied by Glu-142 O 1 in the wild-type enzyme andinteracts with the active site lysine. In the case of the E142D mutant, this site is occupied by Asp-142 O1.In neither case is an atom located at the position of Glu-142 O 2 in the wild-type enzyme. The active site cysteine of the E142Lmutant was found to form aMichael adduct with acrylamide, which is a substrate of the wild-type enzyme, due to an interaction that places the double bond of the acrylamide rather than the amide carbonyl carbon adjacent to the active site cysteine. Our results demonstrate that in the wild-type active site a crucial role is played by the hydrogen bond between Glu-142 O 2 and the substrate amino groupin positioning the substrate with the correct stereoelectronic alignment to enable the nucleophilic attack on the carbonyl carbon by the catalytic cysteine

De novo formation of an aggregation pheromone precursor by an isoprenyl diphosphate synthase-related terpene synthase in the harlequin bug.

Insects use a diverse array of specialized terpene metabolites as pheromones in intraspecific interactions. In contrast to plants and microbes, which employ enzymes called terpene synthases (TPSs) to synthesize terpene metabolites, limited information from few species is available about the enzymatic mechanisms underlying terpene pheromone biosynthesis in insects. Several stink bugs (Hemiptera: Pentatomidae), among them severe agricultural pests, release 15-carbon sesquiterpenes with a bisabolene skeleton as sex or aggregation pheromones. The harlequin bug, Murgantia histrionica, a specialist pest of crucifers, uses two stereoisomers of 10,11-epoxy-1-bisabolen-3-ol as a male-released aggregation pheromone called murgantiol. We show that MhTPS (MhIDS-1), an enzyme unrelated to plant and microbial TPSs but with similarity to trans-isoprenyl diphosphate synthases (IDS) of the core terpene biosynthetic pathway, catalyzes the formation of (1S,6S,7R)-1,10-bisaboladien-1-ol (sesquipiperitol) as a terpene intermediate in murgantiol biosynthesis. Sesquipiperitol, a so-far-unknown compound in animals, also occurs in plants, indicating convergent evolution in the biosynthesis of this sesquiterpene. RNAi-mediated knockdown of MhTPS mRNA confirmed the role of MhTPS in murgantiol biosynthesis. MhTPS expression is highly specific to tissues lining the cuticle of the abdominal sternites of mature males. Phylogenetic analysis suggests that MhTPS is derived from a trans-IDS progenitor and diverged from bona fide trans-IDS proteins including MhIDS-2, which functions as an (E,E)-farnesyl diphosphate (FPP) synthase. Structure-guided mutagenesis revealed several residues critical to MhTPS and MhFPPS activity. The emergence of an IDS-like protein with TPS activity in M. histrionica demonstrates that de novo terpene biosynthesis evolved in the Hemiptera in an adaptation for intraspecific communication

Emerging spin-phonon coupling through cross-talk of two magnetic sublattices.

Many material properties such as superconductivity, magnetoresistance or magnetoelectricity emerge from the non-linear interactions of spins and lattice/phonons. Hence, an in-depth understanding of spin-phonon coupling is at the heart of these properties. While most examples deal with one magnetic lattice only, the simultaneous presence of multiple magnetic orderings yield potentially unknown properties. We demonstrate a strong spin-phonon coupling in SmFeO3 that emerges from the interaction of both, iron and samarium spins. We probe this coupling as a remarkably large shift of phonon frequencies and the appearance of new phonons. The spin-phonon coupling is absent for the magnetic ordering of iron alone but emerges with the additional ordering of the samarium spins. Intriguingly, this ordering is not spontaneous but induced by the iron magnetism. Our findings show an emergent phenomenon from the non-linear interaction by multiple orders, which do not need to occur spontaneously. This allows for a conceptually different approach in the search for yet unknown properties

Complete Genome Sequence of Geobacter sp. Strain FeAm09, a Moderately Acidophilic Soil Bacterium

A moderately acidophilic Geobacter sp. strain, FeAm09, was isolated from forest soil. The complete genome sequence is 4,099,068 bp with an average GC content of 61.1%. No plasmids were detected. The genome contains a total of 3,843 genes and 3,608 protein-coding genes, including genes supporting iron and nitrogen biogeochemical cycling

Pointing control for the SPIDER balloon-borne telescope

We present the technology and control methods developed for the pointing system of the SPIDER experiment. SPIDER is a balloon-borne polarimeter designed to detect the imprint of primordial gravitational waves in the polarization of the Cosmic Microwave Background radiation. We describe the two main components of the telescope's azimuth drive: the reaction wheel and the motorized pivot. A 13 kHz PI control loop runs on a digital signal processor, with feedback from fibre optic rate gyroscopes. This system can control azimuthal speed with < 0.02 deg/s RMS error. To control elevation, SPIDER uses stepper-motor-driven linear actuators to rotate the cryostat, which houses the optical instruments, relative to the outer frame. With the velocity in each axis controlled in this way, higher-level control loops on the onboard flight computers can implement the pointing and scanning observation modes required for the experiment. We have accomplished the non-trivial task of scanning a 5000 lb payload sinusoidally in azimuth at a peak acceleration of 0.8 deg/s$^2$, and a peak speed of 6 deg/s. We can do so while reliably achieving sub-arcminute pointing control accuracy.Comment: 20 pages, 12 figures, Presented at SPIE Ground-based and Airborne Telescopes V, June 23, 2014. To be published in Proceedings of SPIE Volume 914

Biology and Management of Pest Diabrotica Species in South America

The genus Diabrotica has over 400 described species, the majority of them neotropical. However, only three species of neotropical Diabrotica are considered agricultural pests: D. speciosa, D. balteata, and D. viridula. D. speciosa and D. balteata are polyphagous both as adults and during the larval stage. D. viridula are stenophagous during the larval stage, feeding essentially on maize roots, and polyphagous as adults. The larvae of the three species are pests on maize, but D. speciosa larvae also feed on potatoes and peanuts, while D. balteata larvae feed on beans and peanuts. None of these species express a winter/dry season egg diapause, displaying instead several continuous, latitude-mediated generations per year. This hinders the use of crop rotation as a management tool, although early planting can help in the temperate regions of the distribution of D. speciosa. The parasitoids of adults, Celatoria bosqi and Centistes gasseni, do not exert much control on Diabrotica populations, or show potential for inundative biocontrol plans. Management options are limited to insecticide applications and Bt genetically modified (GM) maize. Other techniques that show promise are products using Beauveria bassiana and Heterorhabditis bacteriophora, semiochemical attractants for monitoring purposes or as toxic baits, and plant resistance.Facultad de Ciencias Naturales y Muse