- About
-
The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
provided by the
Networked Digital Library of Theses and Dissertations.
Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
Search results
Showing 1 to 10 of 10 (0.078 seconds)Spelling suggestions: "subject:"locusta migratorio"" "subject:"locusta migratory""
| 1 |
Cuticle-catalyzed coupling between N-acetylhistidine and N-acetyldopamineAndersen, Svend Olav, Perter, Martin G., Roepstorff, Peter January 1992 (has links)
Several types of insect cuticle contain enzymes catalyzing the formation ofof adducts between N-acetyldopamine (NADA) and N-acetylhistidine (NAH). Two such adducts, NAH-NADA-I and NAH NADA-II, have been isolated and their structures determined.
In one of the adducts the link connecting the two residues occurs between the I-position (ß-position) in the NADA side chain and the 1-N atom (τ-N) in the imidazole ring of histidine. Diphenoloxidase activity alone is not sufficient for formation of this adduct, whereas extracts containing both diphenoloxidase and o-quinone-p-quinone methide isomerase activities catalyze the coupling reaction. The adduct consists of a mixture of two diastereomers and they are presumably formed by spontaneous reaction between enzymatically produced NADA-p-quinone methide and N-acetylhistidine.
The other adduct has been identified as a ring addition product of N-acetylhistidine and NADA. In contrast to the former adduct it can be formed by incubation of the two substrates with mushroom tyrosinase alone.
An adduct between N-acetylhistidine and the benzodioxan-type NADA-dimer is produced in vitro, when the N-acetylhistidine-NADA adduct is incubated with NADA and locust cuticle containing a 1,2-dehydro-NADA generating enzyme system.
Trimeric NADA-polymerization products of the substituted benzodioxan-type have been obtained from in vivo sclerotized locust cuticle, confirming the ability of cuticle to produce NADA-oligomers.
The results indicate that some insect cuticles contain enzymes promoting linkage of oxidized NADA to histidine residues. It is suggested that histidine residues in the cuticular proteins can serve as acceptors for oxidized NADA and that further addition of NADA-residues to the phenolic groups of bound NADA can occur, resulting in formation of protein-linked NADA-oligomers. The coupling reactions identified may be an important step in natural cuticular sclerotization.
|
| 2 |
Proteomic Analysis of the Heat Shock Response in the Nervous System of Locusta migratoriaDEHGHANI, MEHRNOUSH 25 March 2009 (has links)
There is a thermal range for the operation of neural circuits beyond which nervous system function is compromised. Poikilotherms are particularly vulnerable to thermal stress, since their body temperature can fluctuate with ambient temperature. Animals that experience frequent hyperthermia have various coping mechanisms such as the thermoprotective effect of a prior exposure to sublethal temperatures (heat shock response). The molecular mechanisms of this thermoprotection have yet to be understood. This project studies the changes in protein expression in the nervous system of gregarious Locusta migratoria subjected to heat shock. For this purpose, proteins were extracted from metathoracic ganglia (MTG) by different methods and a proteomic map was subsequently obtained by 2-D gel electrophoresis which was compared between control (CON) and heat-shocked (HS) animals. Additionally, the localization pattern of Hsp70 was studied in the MTG of CON and HS gregarious locusts. Although 2-D gels showed changes in the amount of different isoforms of ATP-synthase β, the overall amount of this protein subunit was found to be unchanged. My experiments also revealed no significant change in the distribution of Hsp70 in the MTG of locusts caused by HS. However, new findings show that this protein is constitutively expressed at higher levels in perineurium, glia and tracheal cells than in neurons. In separate experiments, isolated locusts were also examined in order to measure any stress-associated increase of Hsp70 in the tissues of animals not previously exposed to crowding pressure. Quantitative western blots did not show a consistent change of the Hsp70 level in the MTG of isolated locusts following heat shock. Results of my research suggest that the change in the protein profile of the metathoracic ganglion following heat shock, if it exists, is subtle or occurs in very low-abundance proteins whose monitoring requires the application of special techniques. Alternatively, the thermoprotective effect of heat shock on the nervous system might be promoted through other pathways which can change the protein activity at the post-translational level and may work independently from protein synthesis. / Thesis (Master, Biology) -- Queen's University, 2009-03-20 12:28:32.962
|
| 3 |
Effects of Heatshock on the Na+/K+-ATPase in Locusta migratoriaHOU, NICHOLAS YUE 27 September 2011 (has links)
Most vertebrates suffer permanent damage after minutes of anoxia. Many insects however, have part of their life cycle in anoxia or constant hypoxia, such as during their egg-hatching phase, by living as deep burrowers, or at high altitudes. Insects are able to survive in anoxia from hours to days, or even months by developing various strategies through evolution. For example, the locusts (Locusta migratoria) enter a reversible coma during anoxia that is associated with an arrest of ventilation, and a reinitiation of ventilation when returned to normoxia. This coma is correlated with a surge in the concentration of extracellular potassium ions ([K+]o), and recovery from this reversible coma is dependent on re-establishing the functional [K+]o. Prior exposure to a sublethal heatshock (HS)-preconditioning grants locusts a temporary resilience to anoxia; however, the molecular mechanisms of this protection are still unclear.
This project investigated the effects of HS-preconditioning on locusts’ ventilation, the total enzymatic activity of the Na+/K+-ATPase, as well as its distribution within the metathoracic ganglion and tested the hypothesis that HS-preconditioning alters locusts’ ventilation and increases the totally Na+/K+-ATPase activity and its concentration within neuronal membranes. I
recorded electromyograms of locusts’ ventilatory motor patterns in the presence and absence of anoxic coma by placing a copper wire electrode on ventilatory muscles 161 or 173 in control and HS-preconditioned animals. In addition, I studied the enzymatic activity of the Na+/K+-ATPase using a pyruvate kinase/lactate dehydrogenase assay and the localization of the Na+/K+-ATPase
using immunohistochemistry in control and HS-preconditioned locusts at different stages of
coma. I found that the ventilatory cycle period was decreased and the ventilatory muscle burst duration was increased after recovery from anoxic coma in HS-preconditioned locusts. I also found that anoxia did not affect the activity or the localization of the Na+/K+-ATPase. However,
HS-preconditioning increased the total activity of the Na+/K+-ATPase and the localization of the Na+/K+-ATPase within the neuronal membranes. From this project, I concluded that HSpreconditioning affected locusts’ ventilatory motor pattern after recover from anoxia and increased the total activity and the neuronal membrane localization of the Na+/K+-ATPase. / Thesis (Master, Biology) -- Queen's University, 2011-09-26 13:14:48.472
|
| 4 |
The Pleiotropic Roles of FGLamide Allatostatins in the African Migratory Locust, Locusta migratoriaRobertson, Lisa 09 August 2013 (has links)
The FGLa/ASTs are one family of allatostatin peptides and share an amidated C-terminal sequence (FGL-amide). The inhibitory effect of FGLa/ASTs on juvenile hormone (JH) biosynthesis in Diploptera punctata led to their discovery, but there is a lack of allatostatic function across most insect species that suggests this function may not be their primary role. Rather, the FGLa/ASTs are implicated as brain/gut peptides, modulating gut physiology. This thesis demonstrates the pleiotropic nature of FGLa/ASTs in Locusta migratoria and emphasizes the role of FGLa/ASTs as brain/gut peptides involved in homeostatic processes.
FGLa/AST-like immunoreactivity (FLI) is associated with the corpus cardiacum (CC) and corpus allatum (CA). FGLa/ASTs increase adipokinetic hormone release from the CC and alter JH biosynthesis from the CA, suggesting roles in energy utilization and in growth and metamorphosis.
Each region of the gut exhibits FLI. The gut is dually innervated: neurons in the abdominal ganglia of the central nervous system (CNS) innervate the posterior gut and some contain FLI, while neurons within the stomatogastric nervous system (STNS) that innervate the anterior gut do not seem to contain FLI, indicating that source of FLI on the gut are cells within the CNS, which may release FGLa/ASTs at the gut to alter aspects of gut physiology. FGLa/ASTs are involved in peristalsis, neural control of foregut contractions, and ileal K+ transport. In particular, FGLa/ASTs inhibit contractions of each gut region and also modulate the rhythmic motor output of a central pattern generator within the ventricular ganglion of the STNS. FGLa/ASTs also inhibit ileal K+ efflux, suggesting a diuretic action and implicating FGLa/ASTs in fluid and ion homeostasis.
This work provides a comprehensive picture of how FGLa/ASTs play an integral role in nutrient processing, energy mobilization, and growth and metamorphosis to contribute to the overall maintenance of homeostasis. This reinforces the role of FGLa/ASTs as brain/gut peptides and emphasizes their involvement in the flexibility of nervous communication and integration of the endocrine system with the CNS to achieve homeostasis.
|
| 5 |
The Pleiotropic Roles of FGLamide Allatostatins in the African Migratory Locust, Locusta migratoriaRobertson, Lisa 09 August 2013 (has links)
The FGLa/ASTs are one family of allatostatin peptides and share an amidated C-terminal sequence (FGL-amide). The inhibitory effect of FGLa/ASTs on juvenile hormone (JH) biosynthesis in Diploptera punctata led to their discovery, but there is a lack of allatostatic function across most insect species that suggests this function may not be their primary role. Rather, the FGLa/ASTs are implicated as brain/gut peptides, modulating gut physiology. This thesis demonstrates the pleiotropic nature of FGLa/ASTs in Locusta migratoria and emphasizes the role of FGLa/ASTs as brain/gut peptides involved in homeostatic processes.
FGLa/AST-like immunoreactivity (FLI) is associated with the corpus cardiacum (CC) and corpus allatum (CA). FGLa/ASTs increase adipokinetic hormone release from the CC and alter JH biosynthesis from the CA, suggesting roles in energy utilization and in growth and metamorphosis.
Each region of the gut exhibits FLI. The gut is dually innervated: neurons in the abdominal ganglia of the central nervous system (CNS) innervate the posterior gut and some contain FLI, while neurons within the stomatogastric nervous system (STNS) that innervate the anterior gut do not seem to contain FLI, indicating that source of FLI on the gut are cells within the CNS, which may release FGLa/ASTs at the gut to alter aspects of gut physiology. FGLa/ASTs are involved in peristalsis, neural control of foregut contractions, and ileal K+ transport. In particular, FGLa/ASTs inhibit contractions of each gut region and also modulate the rhythmic motor output of a central pattern generator within the ventricular ganglion of the STNS. FGLa/ASTs also inhibit ileal K+ efflux, suggesting a diuretic action and implicating FGLa/ASTs in fluid and ion homeostasis.
This work provides a comprehensive picture of how FGLa/ASTs play an integral role in nutrient processing, energy mobilization, and growth and metamorphosis to contribute to the overall maintenance of homeostasis. This reinforces the role of FGLa/ASTs as brain/gut peptides and emphasizes their involvement in the flexibility of nervous communication and integration of the endocrine system with the CNS to achieve homeostasis.
|
| 6 |
Vliv oxidativního stresu na antioxidační systémy, délku telomer a telomerázovou aktivitu u \kur{Locusta migratoria} / Effect of oxidative stress on antioxidant systems, telomere length and telomerase activity in \kur{Locusta migratoria}VRBOVÁ, Kristýna January 2014 (has links)
Oxidative stress is caused by an imbalance between oxidants and antioxidants. Oxidative stress generated by reactive oxygen species (ROS) or reactive nitrogen species (RNS) occurs when protection of antioxidants fails or when an amount of ROS is too high. Telomeres, regions of repetitive nucleotide sequences at the end of chromosomes, are especially sensitive to oxidative stress because they contain a lot of guanine which is often oxidised. Antioxidants play an important role in protection against oxidative stress. In this thesis I analysed the effect of oxidative stress caused by paraquat on activity of antioxidant enzymes (catalase and superoxide dismutase) and telomere length in Locusta migratoria. I also studied differences in telomere length between locusts of various development stages and telomerase activity in locusts and other Orthoptera.
|
| 7 |
Erythropoietin-mediated neuroprotection in insectsMiljus, Natasa 18 May 2016 (has links)
No description available.
|
| 8 |
Functional characterization and molecular identification of neuroprotective receptors for erythropoietin-like ligandsHahn, Nina 12 December 2021 (has links)
No description available.
|
| 9 |
Neural processing of chemosensory information from the locust legs / Motorische Antworten auf Reizung chemorezeptiver Sensomotorik bei locustaGaaboub, Ibrahim Abdalla 01 November 2000 (has links)
No description available.
|
| 10 |
Development and testing of mycoinsecticides based on submerged spores and aerial conidia of the entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae (Deuteromycotina: Hyphomycetes) for control of locusts, grasshoppers and storage pests / Mycoinsecticides for pest control / Biologische Schädlingsbekämpfung / Mykoinsektiziden für SchädlingsbekämpfungKassa, Adane 14 July 2003 (has links)
No description available.
|
Page generated in 0.0862 seconds