Search results for "Locust"
showing 10 items of 38 documents
Locust neuropeptides stimulating sex pheromone production in female European corn borer moth, Ostrinia nubilalis
1990
Abstract The presence of a pheromonotropically active hormone (PBAN-like substance) from locust organs, ( Locusta migratoria ) has been demonstrated. Extracts of brain, corpora cardiaca, corpora allata, suboesophageal ganglia and thoracic ganglia of L. migratoria caused highly pheromonotropic responses in decapitated females of the European corn borer moth ( Ostrinia nubilalis ). The highest activity per unit weight of tissue was found in the corpora cardiaca and corpora allata of the locust followed by the brain plus suboesophageal ganglion of O. nubilalis . Following 8 days of disconnection, separating the corpora allata from the corpora cardiaca and suboesophageal ganglion, the pheromono…
Locust flight metabolism studied in vivo by 31P NMR spectroscopy
1991
Flight metabolism of locusts has been extensively studied, but biochemical and physiological methods have led to conflicting results. For this reason the non-invasive and non-destructive method of 31P NMR spectroscopy was used to study migratory locusts, Locusta migratoria, at rest and during flight. 1. In the flight muscle of resting locusts the ratio of phosphoarginine to ATP was the same whether determined by NMR (1.76) or biochemically, but the NMR-visible content of inorganic phosphate (Pi) was only 40% of ATP, i.e., much lower than total Pi as determined biochemically. This suggests that most of the Pi in flight muscle is not free, and hence not available as substrate or effector for …
Fate and effects of the trehalase inhibitor trehazolin in the migratory locust (Locusta migratoria).
2009
Abstract Trehalose is the main haemolymph sugar in many insect species. To be utilized trehalose must be hydrolysed into its glucose units by trehalase (EC 3.2.1.28). Inhibitors of trehalase have attracted interest as possible pesticides and tools for studying the regulation of trehalose metabolism in insects. To make full use of these inhibitors requires knowledge of their fate and effects in vivo. To this end we have measured trehazolin in locusts using a method based on the specific inhibition of a trehalase preparation. After injection of 20 μg, trehazolin decreased in haemolymph with a half-life of 2.6 days and after 10 days almost 95% had disappeared. Trehazolin did not reach the intr…
Grafiskais romāns kā īpaša stāstījuma forma Nataniēla Vesta darbā “Siseņu diena”
2016
Šajā pētnieciskajā darbā tiek aplūkoti veidi kā detalizēti apraksti, jauna pieeja linearitātei un stāstījuma paņēmieni, proti, sadrumstalotība, montāža un vārdu izlaidums, jeb elipse, rada vizualitātes un gleznainības iespaidu modernista tekstā. Nataniēla Vesta romāns „Siseņu diena” ir piemērs tendencei iztēloties, ka teksta radīšanas paņēmienu izraisītie grafiskie efekti, modernisma literatūrā, veido novatorisku vizuāli-tekstuālu stāstījuma veidu, proti, tādu, kurš līdzinās filmai. Pētījuma mērķis ir noteikt kā romāna gleznainība palīdz autoram radīt jaunu stāstījuma veidu. Pētījumā iegūtie rezultāti var tik izmantoti tālākai literārā modernisma vēstures, kā arī Nataniēla Vesta modernista …
Oscillatory measurements for salad dressings stabilized with modified starch, xanthan gum, and locust bean gum
2006
The rheological properties of low-oil-content food emulsions were analyzed with oscillatory tests within the linear viscoelastic region. The formulations of these salad dressings usually include modified starch because of its low cost and the special creamy texture that it affords. The combination of starch with other natural gums may improve the quality of the product. A reference emulsion containing 4% modified starch and four other formulations in which the starch was partially replaced by xanthan gum (0.4%), locust bean gum (0.4%), and synergistic blends of these gums (0.03 + 0.03% or 0.1 + 0.1%) were formulated. Gels before emulsification were studied for comparative purposes. All syst…
New Method of DNA Isolation from Two Food Additives Suitable for Authentication in Polymerase Chain Reaction Assays
2005
Locust bean gum and guar gum are galactomannans used as additives (E 410 and E 412, respectively) in the food industry as stabilizing agents. Analytical discrimination between the two additives in gums and foods is now feasible by molecular techniques. However, only complex and time-consuming DNA isolation protocols are available to date. We have developed simple improved protocols to obtain enough DNA suitable for PCR amplification from a few milligrams of commercial E 410 and E 412 additives (containing more than 75% polysaccharides). The suspension of additives in water or 10 mM Tris-HCl, pH 8.5, efficiently recovers DNA suitable for authentication in PCR assays. However, the Tris method…
Rheological Characterization of Low-calorie Milk-based Salad Dressings
1992
Oil-in-water emulsions of different quantitative composition, containing milk powder and locust bean gum. as stabilizing agents, showed similar rheological behavior: time-dependent thixotropic character and yield stress. Thixograms obtained for each sample could be modelled through the Hahn equation for the different shear rates. The analysis of the Hahn parameter variation for each sample as a function of shear rate led to a function σ= f(γ, t). Predicted shear stress values had relative errors lower than 10% in 99.9% of the samples studied. Analysis of composition influence on the rheological parameters showed an interactive role of gum, milk and acetic acid concentrations on emulsion con…
A contribution to the study of staling of white bread: effect of water and hydrocolloid
1996
Abstract Staling of white bread at ambient temperature was studied using differential scanning calorimetry and dynamic mechanical thermal analysis. During storage, sample hydration varied slightly, from 0 to 0.4% per day, depending on packaging conditions. An increase in rigidity was observed, which was attributed both to starch retrogradation and to changes in the organization of the amorphous part of crumb. The glass transition temperature of crumb was not significantly modified by these structural changes. Hydrocolloids did not affect the overall shape of the viscoelastic behavior of crumb in the temperature range from −40°C to 80°C, and had a limited influence on the kinetics of starch …
The pattern of histone H4 acetylation on the X chromosome during spermatogenesis of the desert locustSchistocerca gregaria
1996
We have used antibodies directed against histone H4 acetylated at lysine residue 5, 8, 12, or 16 and indirect immunofluorescence microscopy to probe chromosomes from spermatogonia and spermatocytes of the desert locust, Schistocerca gregaria. The autosomes showed bright overall fluorescence, indicative of high levels of H4 acetylation. In contrast, the X chromosome, which is facultatively heterochromatic during spermatogenesis of the locust, remained completely unstained in spermatogonia and secondary spermatocytes and showed only a small terminal fluorescent band in primary spermatocytes. This band probably corresponds to centromere-associated constitutive heterochromatin. Thus, underacety…
Biological Activities of Natural Sesquiterpene Lactones and the Effect of Synthetic Sesquiterpene Derivatives on Insect Juvenile Hormone Biosynthesis
1998
Three natural sesquiterpene lactones have been assayed for their biological activity on locust (Locusta migratoria) nymphs. Since results obtained in vivo pointed to disruptions on juvenile hormone (JH)-regulated physiology, we tested the sesquiterpene lactones and a family of synthetic sesquiterpene derivatives for their ability to disturb the rate of JH biosynthesis by locust corpora allata (CA) in vitro. All the active compounds in vitro share a basic sesquiterpene double-ring structure as well as substituents with different chemical complexities. Compounds that shared an eudesmane base with different oxidation states on C3 and C12 carbon atoms were tested as JH biosynthesis inhibitors. …