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1.
J Econ Entomol ; 116(1): 192-201, 2023 02 10.
Article in English | MEDLINE | ID: mdl-36534944

ABSTRACT

We assessed bioactivity of ethanolic extracts from 35 species of Jatropha L. against an ornamental plant pest, the azalea lace bug, Stephanitis pyrioides (Scott). Jatropha extracts were prepared by air-drying stem, root, or whole plant material, grinding the tissue into a fine powder, adding 70% ethanol, and then vacuum filtering the contents. Emulsions included the extract diluted to the desired concentration in de-ionized water and 10% dimethyl sulfoxide (DMSO). Treatments involved pipetting 20 µl of emulsion onto three adult lace bugs in each well of a 96-well microtiter plate. Treated wells served as replicates for each of six extract concentrations and were arranged according to a RCBD. Extracts of Jatropha clavuligera Müll. Arg. and J. ribifolia (Pohl) Ballion from 0.06 to 0.50% were the most acutely bioactive with bug mortality exceeding that of the positive control - azadirachtin, a terpenoid and chief active ingredient in neem oil. At 1.00%, extracts of J. clavuligera, J. ribifolia and azadirachtin killed 100% of bugs within 3 hr. Jatropha clavuligera induced the lowest LC50 and ranked first in insecticidal potency based on ≥98% of bugs dying within 3 hr. Extracts of J. curcas L., J. gossypiifolia L., J. excisa Griseb, and azadirachtin were equally bioactive; although after 3 hr, the three Jatropha species killed bugs faster. When compared with DMSO, all extract emulsions were bioactive against adult bugs. Thus, active ingredients in a new biopesticide could be sourced from the stem, root, or whole plant extracts of at least five Jatropha species.


Subject(s)
Heteroptera , Insecticides , Jatropha , Animals , Insecticides/pharmacology , Dimethyl Sulfoxide , Emulsions , Plant Extracts/pharmacology
2.
Sci Rep ; 10(1): 5634, 2020 Mar 27.
Article in English | MEDLINE | ID: mdl-32221373

ABSTRACT

Femtosecond (fs) x-ray pulses are a key tool to study the structure and dynamics of matter on its natural length and time scale. To complement radio-frequency accelerator-based large-scale facilities, novel laser-based mechanisms hold promise for compact laboratory-scale x-ray sources. Laser-plasma driven undulator radiation in particular offers high peak-brightness, optically synchronized few-fs pulses reaching into the few-nanometer (nm) regime. To date, however, few experiments have successfully demonstrated plasma-driven undulator radiation. Those that have, typically operated at single and comparably long wavelengths. Here we demonstrate plasma-driven undulator radiation with octave-spanning tuneability at discrete wavelengths reaching from 13 nm to 4 nm. Studying spontaneous undulator radiation is an important step towards a plasma-driven free-electron laser. Our specific setup creates a photon pulse, which closely resembles the plasma electron bunch length and charge profile and thus might enable novel methods to characterize the longitudinal electron phase space.

4.
J Econ Entomol ; 110(2): 530-534, 2017 04 01.
Article in English | MEDLINE | ID: mdl-28334255

ABSTRACT

We report on the efficacy of 0.5 M (61,000 ppm) erythritol (E) in Truvia Baking Blend, 10 ppm lufenuron (L), and their combination (LE) to reduce egg and larval densities of wild populations of Drosophila suzukii (Matsumura) infesting fields of rabbiteye blueberries (Vaccinium virgatum) and blackberries (Rubus sp.). Formulations included the active ingredients (lufenuron, erythritol, or both), sugar (in control and erythritol treatments), and Dawn hand-soap applied to plants with pressurized 3-gallon garden spray tanks. The three chemical treatments (E, L, and LE) had no effect on D. suzukii ovipositing in blackberry and blueberry fruit, but they did reduce larval infestation by 75%, particularly densities of first and second instars. Erythritol and lufenuron were equally efficacious compounds as a D. suzukii ovicide and larvicide, but they did not display additive or synergistic activity. Extremely high larval mortality in control fruits show an age structure heavily skewed toward egg output.


Subject(s)
Benzamides/pharmacology , Crop Protection/methods , Drosophila/drug effects , Erythritol/pharmacology , Age Factors , Animals , Blueberry Plants , Insect Control , Mississippi , Ovum/drug effects , Rubus
5.
J Econ Entomol ; 108(6): 2589-98, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26470379

ABSTRACT

We investigated fitness in natural populations of a managed solitary bee Osmia ribifloris Cockerell (Hymenoptera: Megachilidae) from sites separated from 400 to 2,700 km. Parental wild bees originated in central Texas (TX), central-northern Utah (UT), and central California (CA). They were then intercrossed and raised inside a mesh enclosure in southern Mississippi (MS). Females from all possible mated pairs of O. ribifloris produced F1 broods with 30-40% female cocoons and outcrossed progeny were 30% heavier. Mitochondrial (COI) genomes of the four populations revealed three distinct clades, a TX-CA clade, a UT clade, and an MS clade, the latter (MS) representing captive progeny of CA and UT bees. Although classified as separate subspecies, TX and CA populations from 30° N to 38° N latitude shared 98% similarity in COI genomes and the greatest brood biomass per nest straw (600- to 700-mg brood). Thus, TX and CA bees show greater adaptation for southern U.S. sites. In contrast, UT-sourced bees were more distantly related to TX and CA bees and also produced ∼50% fewer brood. These results, taken together, confirm that adult O. ribifloris from all trap-nest sites are genetically compatible, but some phenotypic variation exists that could affect this species performance as a commercial blueberry pollinator. Males, their sperm, or perhaps a substance in their sperm helped stabilize our captive bee population by promoting legitimate nesting over nest usurpation. Otherwise, without insemination, 50% fewer females nested (they nested 14 d late) and 20% usurped nests, killing 33-67% of brood in affected nests.


Subject(s)
Bees/genetics , DNA, Mitochondrial/chemistry , Genetic Fitness , Phenotype , Animals , Blueberry Plants , Female , Male , Nesting Behavior
6.
Genet Mol Res ; 14(4): 19057-65, 2015 Dec 29.
Article in English | MEDLINE | ID: mdl-26782556

ABSTRACT

Salmonella enterica subsp enterica serovar 4,5,12:i:- has been responsible for many recent Salmonella outbreaks worldwide. Several studies indicate that this serovar originated from S. enterica subsp enterica serovar Typhimurium, by the loss of the flagellar phase II gene (fljB) and adjacent sequences. However, at least two different clones of S. enterica 4,5,12:i:- exist that differs in the molecular events responsible for fljB deletion. The aim of this study was to test the stability of the fljBA operon responsible for the flagellar phase variation under different growth conditions in order to verify if its deletion is a frequent event that could explain the origin and dissemination of this serovar. In fact, coding sequences for transposons are present near this operon and in some strains, such as S. enterica Typhimurium LT2, the Fels-2 prophage gene is inserted near this operon. The presence of mobile DNA could confer instability to this region. In order to examine this, the cat (chloramphenicol acetyltransferase) gene was inserted adjacent to the fljBA operon so that deletions involving this genomic region could be identified. After growing S. enterica chloramphenicol-resistant strains under different conditions, more than 104 colonies were tested for the loss of chloramphenicol resistance. However, none of the colonies were sensitive to chloramphenicol. These data suggest that the origin of S. enterica serovar 4,5,12:i:- from Typhimurium by fljBA deletion is not a frequent event. The origin and dissemination of 4,5,12:i:- raise several questions about the role of flagellar phase variation in virulence.


Subject(s)
Operon , Salmonella typhimurium/genetics , Animals , Anti-Bacterial Agents/pharmacology , DNA Sequence, Unstable , DNA, Bacterial/genetics , Drug Resistance, Bacterial/genetics , Evolution, Molecular , Female , Genes, Bacterial , Mice, Inbred BALB C , Microbial Sensitivity Tests , Mitomycin/pharmacology , Salmonella Infections/microbiology
7.
Rev Sci Instrum ; 82(2): 023705, 2011 Feb.
Article in English | MEDLINE | ID: mdl-21361599

ABSTRACT

A noncontact atomic force microscope (nc-AFM) operating in magnetic fields up to ±7 T and liquid helium temperatures is presented in this article. In many common AFM experiments the cantilever is mounted parallel to the sample surface, while in our system the cantilever is assembled perpendicular to it; the so called pendulum mode of AFM operation. In this mode measurements employing very soft and, therefore, ultrasensitive cantilevers can be performed. The ultrahigh vacuum conditions allow to prepare and transfer cantilevers and samples in a requested manner avoiding surface contamination. We demonstrate the possibility of nc-AFM and Kelvin force probe microscopy imaging in the pendulum mode. Ultrasensitive experiments on small spin ensembles are presented as well.

9.
Rev Rhum Mal Osteoartic ; 59(9): 567-70, 1992 Oct.
Article in French | MEDLINE | ID: mdl-1494739

ABSTRACT

A 52-year-old male developed hypertrophy of the right calf after several bouts of right lumbar pain with sciatica. Electromyography disclosed evidence of demyelination in the territories of the right S1 and S2 roots. Microscopic studies showed both atrophic muscle fibers scattered among fibers of normal caliber and a large number of hypertrophic fibers. Post-sciatica hypertrophy of the calf is a true muscle hypertrophy with muscle weakness. Electromyography may show unusual tracings with repeated complex bursts or continuous activity of motor units. Muscle enzyme levels may be elevated. The size of hypertrophied fibers varies across cases. The cause of the muscle fiber hypertrophy may be either stretching due to the action of antagonists or unusual electrical activity.


Subject(s)
Muscles/pathology , Sciatica/complications , Spinal Nerve Roots , Electromyography , Humans , Hypertrophy/complications , Hypertrophy/physiopathology , Male , Middle Aged , Muscles/physiopathology
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