Thesis--Jena. / Includes bibliographical references (p. [55]-60).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thèse--Université de Paris.

The morphology and histochemistry of the blood cells and tunic of the ascidian Halocynthia aurantium were studied. The nature of the tunic was investigated by both chemical and biochemical means. Quantitative studies of the blood of Halocynthia display ten blood cell types, four of which are concentrated in tunic in higher concentrations than in blood. Of these four, two, including an iron bearing cell, display discrete stable aggregation areas in the body of the tunic, and a third is a phagocyte. Histochemical examination of the tunic and blood cells reveals that the tunic fibers and epidermis stain for acid mucopolysaccharide and protein. The spinous processes on the surface of the tunic do not stain like the epidermis or fibers, but do display some similarity to the blood cell type which aggregates in their proximity. There is a coincidence of absorption spectra of methanol extracts of blood cells and tunic, but no particular blood cell has been indicated as the pigment cell. The blood cells, in the tunic, do not display staining properties which would indicate that they are contributing to the carbohydrate component. Morphological characteristics and histochemical properties of epidermis indicate that it is the major tunic secreting tissue. The histogenetic relationship of various blood cells is discussed on the basis of analogous histochemistry and quantitative hematology. The function of particular blood cell types in the tunic is suggested by the discrete positional relationships of cells and the morphology of the tunic. The chemical composition of tunic is approximately 50% protein and 50% carbohydrate. Amino acid analysis of tunic before and after proteolytic enzyme treatment shows that the protein does not have the characteristics of common connective tissue proteins such as collagen, elastin, or others, and that the protein-polysaccharide link probably involves glucosamine and serine. Five per cent of the dry weight of tunic is hexosamine with both galactosamine and glucosamine present in a ratio of 1 to 4. The carbohydrate component of the tunic releases 75% of its weight as glucose upon acid hydrolysis. This carbohydrate consistently displays a negative P.A.S. reaction and is resistant to several cellulose dispersing reagents. The elemental composition of the carbohydrate reveals a hydrogen content which is too low and an oxygen content which is too high to indicate cellulose. Tunic, pronase treated tunic, and tunic carbohydrate were submitted to cellulase, chitinase, and hyaluronidase digestion. None of these materials are subject to degradation by chitinase or hyaluronidase. Tunic is refractory to cellulase. Pronase treated tunic will release 20% of its weight as glucose upon incubation with cellulase. Tunic carbohydrate component will release 55% of its weight as glucose upon cellulase treatment, although chemical properties indicate that it may be more complex than cellulose. / Science, Faculty of / Zoology, Department of / Graduate

This study investigated the spatial and temporal distribution in species composition and numerical abundance of thaliaceans (Tunicata) in relation to environmental factors in the waters off southern Taiwan between February 2004 and October 2005. In total, 18 thaliacean taxa belonging to 10 genera and 3 families were identified, with the mean abundance of 152 ¡Ó 33 ind./100m3. The abundance of thaliaceans showed clear seasonal change, higher in winter. The five most dominant species were Thalia rhomboides, Pyrosomella verticillata, Doliolum denticulatum, Thalia orientalis and Thalia democratica. They were widespread oceanic species, and together constituted 82 % of the total thaliaceans. The abundance of thaliaceans showed significant negative correlation with temperature. Different predominant thaliacean species showed different correlationship with environmental factors; Thalia rhomboides, Doliolum denticulatum and Thalia orientalis were significant and negatively correlated with temperature. Result of ANOVA test revealed that the abundance of thaliaceans and hydrography had significant seasonal differences in the waters off southern Taiwan, but showed no significant difference among stations. The variation of dominant thaliacean species composition among the water masses was small, implied that the influence of water masses on the distribution of thaliaceans was minor.

Thesis (Ph. D.)--Joint Program in Oceanography (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), 2010. / Department of origin: Biology. "February 2010." Bibliography: p.91-99.

The eukaryote-associated Pseudoalteromonas tunicata produces two pigments and several other bioactive compounds that are able to inhibit a range of marine organisms including bacteria, protozoa, fungi, algal spores and invertebrate larvae. Early studies suggested that the production of bioactive compounds is correlated with pigmentation in P. tunicata. In one of these studies, a transposon mutagenesis library identified a white mutant, wmpD-, which had been disrupted in a gene encoding a component of the type 11 secretion (T2S) machinery. The T2S system is involved in the transport of different extracellular enzymes in many bacteria. In some cases, the T2S pathway also exports proteins that remain attached to the cells. This thesis aimed to investigate the role of the T2S pathway in the production of the pigments and bioactive compounds in P. tunicata. In order to gain insight into this relationship, two proteomics approaches (2D-PAGE and iTRAQ) were applied to investigate the profile of the secreted proteins (or secretome) in P. tunicata wild-type and the white mutant wmpD-. Proteomic analysis using 2D-PAGE revealed that 23 proteins were differentially expressed between P. tunicata Wt and the mutant wmpD-. The identities of some of these proteins could be correlated with the function of the T2S system in P. tunicata. The role of one of the proteins identified using 2D-PAGE was further investigated through the construction of a gene knockout mutant (hiik mutant). The supernatant activity of the hiik mutant was compared to that of P. tunicata Wt, and it was found that the HiiA protease is required to block the activity of antimicrobial peptides, such as cecropins, produced by eukaryotic hosts in the environment. The second proteomics approach (iTRAQ) used in this thesis, enabled the relative quantitation of a number of proteins in the supernatant of P. tunicata Wt and the white mutant wmpD-. Some proteins with no function to date (hypothetical) were absent in the extracellular fraction of the wmpD- mutant, indicating they may be transported to the extracellular environment via the T2S pathway in P. tunicata. The comparative analysis of the secretome also revealed that TonS-related proteins, involved in iron acquisition, were up-regulated in the wmpD- mutant, possibly to compensate for the lack of TonS-dependant receptors in the outer membrane. Assays for iron binding activity showed that P. tunicata Wt seems to release iron binding compounds (or siderophores) constitutively into the supernatant, in contrast to the white mutant wmpD-, which responds to iron limitation by increasing the production of siderophores. Further outer membrane fractionation studies, indicated that the P. tunicata T2S system is likely to be involved in the transport of TonB-dependant receptors to the outer membrane. The overall results discussed in this thesis indicate that the T2S system has an essential role in the general physiology of P. tunicata, as for iron metabolism, as well as in the in the relationship between this bacterium and eukaryotic hosts in the environment.

Thesis (Ph. D.)--University of Oregon, 2002. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 125-138). Also available for download via the World Wide Web; free to University of Oregon users.

Thesis (Ph. D.)--Memorial University of Newfoundland, 1997. / Blbliography: leaves 185-205.

Thesis (Ph. D.)--University of Chicago, Committee on Evolutionary Biology, Jun. 2003. / Includes bibliographical references. Also available on the Internet.