The Experts below are selected from a list of 120 Experts worldwide ranked by ideXlab platform
Bryan C Rourke - One of the best experts on this subject based on the ideXlab platform.
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geographic and altitudinal variation in water balance and metabolic rate in a california grasshopper Melanoplus sanguinipes
The Journal of Experimental Biology, 2000Co-Authors: Bryan C RourkeAbstract:The importance of respiratory patterns and the physical properties of cuticular lipids to insect water balance were investigated in natural populations of the grasshopper Melanoplus sanguinipes. I specifically test the hypotheses that patterns of discontinuous ventilation affect water loss and that increased amounts and melting points of cuticular lipid reduce water loss. Using flow-through respirometry, rates of water loss and carbon dioxide release from grasshoppers were quantified at 25, 35 and 42 degrees C. Populations displayed substantial variation, with high-elevation populations exhibiting the greatest water loss and metabolic rates. Behavior leading to discontinuous gas exchange was observed in several populations, but its occurrence decreased dramatically at high temperatures and was not correlated with a reduction in the rate of water loss. The amount and melting point of cuticular lipids were determined for each individual using gas chromatography and Fourier-transform infrared spectroscopy. Increased amounts and higher melting points of cuticular lipids were strongly correlated with lower rates of water loss in populations. I show that discontinuous gas exchange is unlikely to be a mechanism for reducing water loss in these insects and that the lipid properties are primarily responsible for variation in overall water loss rates.
Jane E Allison - One of the best experts on this subject based on the ideXlab platform.
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cerium chloride heptahydrate cecl3 7h2o induces muscle paralysis in the generalist herbivore Melanoplus sanguinipes fabricius orthoptera acrididae fed contaminated plant tissues
Chemosphere, 2015Co-Authors: Jane E Allison, Celine Boutin, David Carpenter, Deanna M Ellis, Jessica L ParsonsAbstract:Abstract Of increasing economic importance are the rare earth elements (REEs). Pollution from mining and processing activity is expected to rise with industrial demand. Plants are known to accumulate REEs, although levels vary with species and soil content. However, the effect on wildlife of ingesting REE contaminated vegetation is not well understood. Here we examined the effect of consuming vegetation with elevated levels of cerium on the generalist grasshopper, Melanoplus sanguinipes (Fabricius). Adults excreted a substantial portion of ingested contamination. However, after only four-days of feeding, accumulation in the body occurred at all doses and paralysis of appendages resulted at the highest doses. Short-term toxicity studies may underestimate the impact of ingesting REE contamination. Metals tend to be low in toxicity; however, their persistence in the environment may be better represented by exposure over longer portions of the life cycle.
Mary Ann Rankin - One of the best experts on this subject based on the ideXlab platform.
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Fluorescein-dextran sequestration in the reproductive tract of the migratory grasshopper Melanoplus sanguinipes (Orthoptera, Acridiidae).
Micron (Oxford England : 1993), 2012Co-Authors: Nathan T. Jones, Tina E. Taub-montemayor, Mary Ann RankinAbstract:The fluid dynamics of the reproductive system of the migratory grasshopper, Melanoplus sanguinipes F. (Orthoptera: Acrididae) was examined by the introduction of fluorescein-dextran (FD) into the hemocoel and observing its tissue specific sequestration. Male grasshoppers were observed to sequester FD first in the apical end of each sperm tube. FD then moved into the vasa deferentia and ejaculatory duct. This suggests that materials, that transit the hemolymph could be a component of the spermatophore in M. sanguinipes. Female grasshoppers were observed to sequester hemolymph FD into vitellogenic oocytes and to sometimes reuptake the FD during the resorption of oocytes in the formation of yellow bodies or corpora lutea. Female M. sanguinipes who performed long duration flight sequestered FD in their oocytes to a greater degree than controls as determined by fluorescence intensity data collected as the mean gray value of the flourescein emission channel. Transfer of hemolymph FD from males to females was observed at the pores along the margin of the operculum of eggs in the female common oviduct following mating. FD has the potential to be an effective tracker of male reproductive secretions and as a tool for the observation of insect reproductive tract development.
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Discovery and characterization of Melanoplus sanguinipes AKH II by combined HPLC and mass spectrometry methods.
Journal of biomolecular techniques : JBT, 2002Co-Authors: Tina E. Taub-montemayor, Jack W. Kent, Klaus D. Linse, Kyung-jin Min, Mary Ann RankinAbstract:Reversed-phase high-performance liquid chromatography (RP-HPLC) allows for fractionation of extract from the corpora cardiaca of insects for examination of bioactivity or immunoreactivity and/or subsequent characterization of the peptides. Using RP-HPLC, we have previously identified an adipokinetic hormone (AKH) from the corpora cardiaca of the migratory grasshopper Melanoplus sanguinipes. This hydrophobic decapeptide has the same primary structure as locust (Locusta migratoria; Lom) AKH I. Initially, only one HPLC peak with the same retention time as Lom-AKH I was detected; however, we found a second putative AKH within this fraction by using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) and micro HPLC tandem electrospray ionization mass spectrometry. Armed with this information, we were able to improve the resolution of the native AKHs by micro HPLC, which allowed us to characterize the peptide. Our results show the power of coupling HPLC and mass spectrometric methods to resolve and identify very similar hydrophobic peptides at the lower picomole level.
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Heritability and physiological correlates of migratory tendency in the grasshopper Melanoplus sanguinipes
Physiological Entomology, 2001Co-Authors: Jack W. Kent, Mary Ann RankinAbstract:. Durations of tethered flights by the North American migratory grasshopper Melanoplus sanguinipes Fabricius are bimodally distributed: most individuals either will not fly, or else will fly for many hours. This observation suggests a simple measure (the ‘one-hour rule’) for distinguishing migrants from non-migrants. This measure is repeatable (repeatability = 0.6–0.7). Using laboratory-reared offspring of grasshoppers from an Arizona population of mixed migratory tendency, a breeding experiment was conducted to determine the heritability of migratory tendency and possible correlated responses to selection on migratory behaviour. When migratory tendency is considered as a threshold trait, the heritability of liability is in the range 0.5–0.6. Most families in the breeding experiment had at least some migrants among their offspring; selection on migratory incidence had a correlated effect on the durations of flights by these individuals. The magnitude of thoracic lipid reserves showed a modest correlated response to selection on migratory behaviour. Thoracic and abdominal lipid reserves in identified migrants are reduced by flight, indicating that lipid is mobilized and consumed during flight in this species.
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Mobilization of lipid and carbohydrate reserves in the migratory grasshopper Melanoplus sanguinipes
Physiological Entomology, 1997Co-Authors: Jack W. Kent, Yueh‐mei Teng, Dipa Deshpande, Mary Ann RankinAbstract:. The North American migratory grasshopper Melanoplus sanguinipes Fabricius (Orthoptera: Acrididae) exhibits heritable variation in predisposition to make long-duration flights, and performance of long-duration flight enhances reproductive output. As a first step in understanding the physiological basis of these phenomena, we examined the mobilization of lipid and carbohydrate reserves during flight and in response to injection of extracts of the corpora cardiaca. Extract of conspecific corpora cardiaca elevates the concentration of haemolymph lipid. Both synthetic locust adipokinetic hormone I (AKH I) and synthetic Locusta migratoria AKH II raise the concentration of lipid in the haemolymph. However, although AKH I is more active than AKH II in locusts, dose-response curves for the two peptides are similar in M.sanguinipes. Neither extract of conspecific corpora cardiaca nor locust AKH I affects haemolymph carbohydrate in this species. Haemolymph carbohydrate and total glycogen reserves are Diminished by tethered flight; in contrast, haemolymph lipid is elevated by flight. Grasshoppers identified as presumptive migrants or non-migrants do not differ significantly in body composition. Total lipid reserves did not decrease measurably after extended flight, even though total reserves of carbohydrate do not appear to be sufficient to maintain the durations of flight performed.
Martin A. Erlandson - One of the best experts on this subject based on the ideXlab platform.
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Protease activity associated with occlusion body preparations of an entomopoxvirus from Melanoplus sanguinipes
Journal of Invertebrate Pathology, 1991Co-Authors: Martin A. ErlandsonAbstract:Abstract An alkaline protease, associated with Melanoplus sanguinipes entomopoxvirus occlusion body preparations, was characterized. The protease had a p H optimum between 8 and 9 and a temperature optimum between 45 and 50°C. Protease activity was inhibited by phenylmethylsulfonyl fluoride, an inhibitor of serine proteases. The protease was shown to have trypsin-like activity based on the hydrolysis of a trypsin-specific synthetic substrate and inhibition by a trypsin-specific inhibitor. The protease was inactivated by heat treatment above 60°C. Heat treatment (>70°C) inhibited complete dissolution of the occlusion bodies and the release of virions in alkaline dissolution buffer. In dissolution buffer, the occlusion body matrix protein, spheroidin (108.8 kDa), was degraded into smaller polypeptides.
Jessica L Parsons - One of the best experts on this subject based on the ideXlab platform.
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cerium chloride heptahydrate cecl3 7h2o induces muscle paralysis in the generalist herbivore Melanoplus sanguinipes fabricius orthoptera acrididae fed contaminated plant tissues
Chemosphere, 2015Co-Authors: Jane E Allison, Celine Boutin, David Carpenter, Deanna M Ellis, Jessica L ParsonsAbstract:Abstract Of increasing economic importance are the rare earth elements (REEs). Pollution from mining and processing activity is expected to rise with industrial demand. Plants are known to accumulate REEs, although levels vary with species and soil content. However, the effect on wildlife of ingesting REE contaminated vegetation is not well understood. Here we examined the effect of consuming vegetation with elevated levels of cerium on the generalist grasshopper, Melanoplus sanguinipes (Fabricius). Adults excreted a substantial portion of ingested contamination. However, after only four-days of feeding, accumulation in the body occurred at all doses and paralysis of appendages resulted at the highest doses. Short-term toxicity studies may underestimate the impact of ingesting REE contamination. Metals tend to be low in toxicity; however, their persistence in the environment may be better represented by exposure over longer portions of the life cycle.