Thesis--Copenhagen. / On cover: I kommission hos G.E.C. Gad. "Historie.-Litteratur": p. [11]-16. "Litteraturfortegnelse": p. [xxxi]-xxxvi.

Thesis--Copenhagen. / On cover: I kommission hos G.E.C. Gad. "Historie.--Litteratur": p. [11]-16. "Litteraturfortegnelse": p. [xxxi]-xxxvi.

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 123-127).

This project focused on improving the in vitro rearing methods of Toxoneuron nigriceps, an important biological control agent of Heliothis virescens, by supplementing the rearing media with the host hemolymph. T. nigriceps larvae of different ages were incubated in the artificial rearing media. The growth (increase in length and width), development (molting), and survival of the incubated larvae were observed. Changes in osmotic pressure of the rearing media before and after incubation were evaluated. The protein profiles of day 1, 3 and 5 hemolymph samples of the parasitized and unparasitized H. virescens fifth instar larvae, used in the artificial rearing media, were determined. Host hemolymph improved the growth and development of T. nigriceps larvae in the artificial rearing media except in the case of new and early first instar larvae. Osmotic pressure of all media showed a significant decrease after the incubation of the larvae except media incubated with the new first instar larvae indicating that the older larvae absorbed and utilized more of the nutrients from the rearing media than the younger larvae. Growth and development was higher in the semisolid media than in the liquid media. In the artificial rearing media, the late first instar T. nigriceps larvae molted to second instars and a few of them molted to third instars. The early and late second instar larvae incubated in the artificial media also grew well and molted to third instars. Some of the in vitro reared third instar larvae demonstrated behavioral changes that could be expressed as the preparation for cocoon formation or pupation, however neither a cocoon nor pupation occurred. No qualitative differences in the protein titers were detected between hemolymph of the parasitized and unparasitized fifth instar H. virescens larvae. There was a significant increase in the protein concentration in both unparasitized and parasitized H. virescens larvae as the age increased. This increase in the protein concentration showed a positive effect on the growth and development of T. nigriceps larvae indicating that availability of nutrients was an important factor for the growth of T. nigriceps larvae in vitro.

This study sought to examine the physiological correlates of migratory flight performance the North American migratory grasshopper Melanoplus sanguinipes Fabricius (Orthoptera: Acrididae) with a focus on mechanisms of resource allocation, the dynamics of hemolymph proteins, their interface with immune function, and the mechanism of flight-enhanced oogenesis. The performance of long duration flights has been shown previously to be of reproductive benefit to females who make them. Examination of possible mechanisms of resource compensation for the costs of flight showed no significant increase in either feeding, mating or digestion in females who performed long duration flight. A comparison of two populations of M. sanguinipes from Arizona and Colorado showed significant variation in body size, diapause regulation as well as internal and external morphology. The two populations did not differ in taxonomic characters or in short sequences of genomic and mitochondrial DNA. The follicle cell epithelium of ovaries from M. sanguinipes was examined for its relationship to juvenile hormone III (JH III). JH III induces patency in vitro in intercellular spaces of M. sanguinipes follicular epithelium as well as the characteristic apical endocytosis at the follicle cell oocyte interface. Exogenous JH III treatment of females on day 7 in lieu of flight reduced the threshold for induction of patency to 10-7 M JH III from 10-5 M JH III. These results indicate that JH III can act as a prime to the pump of oogenesis. An HPLC/LC-MS peptidomic survey of the hemolymph of M. sanguinipes following flight performance showed the presence of and changes in serine protease inhibitors. These peptides regulate numerous protease cascades involved in reproduction and immunity which suggested that flight might have a more broad impact than previously thought. Males who performed these flights showed a higher probability of surviving a bacterial challenge. The duration of flight performance was positively correlated in males with increases in titers of the hemolymph lipoproteins apolipophorin I and hexemerin. The exchangeable apolipophorin III showed no variation in correlation with flight. Females were not affected by flight performance in terms of hemolymph protein titers or the probability of surviving a bacterial challenge. These results suggest that the lipid transport system plays an important role in the immune response of this insect. / text

Thesis (M.S.) in Food Science and Human Nutrition--University of Maine, 2008. / Includes vita. Includes bibliographical references (leaves 104-107).

No description available.

No description available.

Rhythmic collapse and reinflation of tracheal tubes is a form of active ventilation that augments convective gas exchange in multiple orders of insects. The underlying mechanism driving this phenomenon is not known. Among other things, tracheal tube collapse could be caused by either direct impingement of trachea or by a difference of pressure gradients between the intra-tracheal air and the surrounding hemolymph. To determine the relationship between hemolymph pressure and tracheal tube collapse in the ground beetle (Pterostichus commutabulis), we performed direct measurements of hemolymph pressure inside the beetle's prothorax while simultaneously using synchrotron phase contrast imaging to observe morphological changes in the trachea. We observed that a pressure pulse co-occurred with every tube compression observed throughout the body, suggesting that pulses in hemolymph pressure are responsible for tracheal collapse. To assess the effects of the experimental x-ray conditions imposed on the subjects during imaging, hemolymph pressure was also directly measured in the prothorax of beetles less restricted in non-x-ray trials. To compare the pressure patterns in the two experiments, a novel method of identifying and analyzing pressure pulses was developed and applied to the data sets. The comparison provides the first quantitative characterization of a directly measured hemolymph pressure environment, and demonstrates strong similarities in the pressure patterns recorded in both tests. However, pulses occurring during the x-ray experiments exhibited larger average magnitudes. Further video analysis however shows that collapse of the primary tracheal tubes was observed to occur even in the presence of the smallest simultaneously measured pressure pulse (1.01 kPa), suggesting that collapse of the primary tracheal tubes. / Master of Science

Doctor of Philosophy / Biochemistry / Michael R. Kanost / Insect innate immune responses include prophenoloxidase activation and antimicrobial peptide production. These responses involve extracellular serine proteinase cascades that are regulated by serpins. This work involved the study of serine proteinase 16 (HP16) and serpin-3 from hemolymph of the tobacco hornworm, Manduca sexta. HP16 has an amino-terminal domain with no similarity to any characterized protein and a carboxyl-terminal S1 family serine proteinase domain. HP16 levels in plasma were highest during the wandering, prepupal, and pupal stages. HP16 mRNA levels in fat body were highest at the wandering stage. Injection of bacteria into fifth instar larvae stimulated HP16 expression. To further characterize and investigate the biological function of HP16, recombinant proteins for proHP16, two HP16 mutants, the amino-terminal domain (NT16), and three NT16 mutants were purified. Recombinant HP16 was cleaved at the predicted activation site during expression, and its amino-terminal and catalytic domains remained connected by a disulfide bond. ProHP16 in plasma was apparently activated in the presence of the microbial elicitor, zymosan. Recombinant HP16 formed a complex with serpin-1Z, indicating that it was catalytically active, but no other natural or artificial substrates were identified. Analysis of NT16 and NT16 mutants led to the discovery that multiple disulfide bond arrangements were formed in the recombinant amino-terminal domain of HP16. This work furthered the understanding of HP16 and laid a foundation for subsequent experiments involving the proteolytic activity, regulation, and biological function of HP16. Active serine proteinases in insect hemolymph are often regulated by serpins. Immunoaffinity chromatography was used to identify plasma proteinases that are inhibited by serpin-3. Four serpin-3-proteinase complexes purified from plasma were identified by immunoblot analysis as serpin-3 complexes with HP8, PAP-1, PAP-2, and PAP-3. MALDI-TOF/TOF or ESI-MS/MS analysis after separation by 1D- or 2D-PAGE confirmed serpin-3 complex formation with HP8, PAP-1, and PAP-3. ProHP8 in plasma was activated by exposure to the β-1,3-glucan curdlan and inhibited by serpin-3. Purified recombinant serpin-3 and active HP8-Xa formed an SDS-stable complex in vitro. Identification of serpin-3-proteinase complexes in plasma provides insight into proteinase targets of serpin-3 and extends the understanding of serpin/proteinase function in the immune response of M. sexta.