The Pea Crab, Pinniza longpies, is commensal with the tube building polychaete, Axiothella rubrocincta. This worm constructs U-shaped tubes in san-mud substrata of bays and estuaries along the Pacific coast. The pronounced lateral elongation and diminutive size of p. Longpies enable it to move easily in the narrow tube with the worm. The species has occasionally been found with other polychaetes, including Pectinaria and Pista. According to Schmitt et al (1973) Pinnixa longpies range from Tomales Bay to Laguna Beach in California. There are no published accounts regarding the biology of this commensal crab. The present paper reports in detail on the larval development of P. longpies as reared under laboratory conditions. These results are compared with previous descriptions of Pinnotherid larvae.

A handful of rat species are among the most pervasive mammal species across the globe, primarily because of their close relationship with humans. The processes involved in this relationship, commensalism, are described in detail. Two rat species, Rattus rattus and Rattus exulans, are the focus of this thesis and their biology and taxonomy are described and discussed. Their modern distributions are the direct result of some of the earliest and most extensive human migration events in human history. The archaeology of the Pacific and Indian Oceans is described and migration vectors and spheres of interaction are identified. These possible patterns of human migration and exchange networks provide testable hypotheses that can be investigated using the subject rat species as proxies for long distance human movement. Modern and archaeological tooth samples of R. exulans and modern samples of R. rattus are analysed using geometric morphometrics. The results reveal important aspects of human migration and differences between these species' biology. R. exulans was likely to have been transported out of Island Southeast Asia at a very early date. Human colonisation of the Pacific occurred in a series of complex pulses and pauses that are clearly reflected in the R. exulans data. For the first time it is possible to demonstrate, within one dataset, the multiple origins and directions of colonisation across the Pacific. The R. rattus data provides a striking comparison, showing very different results that allude to a different level of modern gene-­‐ flow and therefore a difference in behaviour and biology. The results provide a framework for comparison with future archaeological material. The results presented and hypotheses raised have immediate application to existing archaeological material and areas of interest. Further commensal species should be examined following similar lines of questioning as applied here.

Thesis--Auburn University, 2007. / Abstract. Vita. Includes bibliographic references (p.57-63).

Bacteria of the Neisseria are predominately commensal, though N. gonorrhoeae and N. meningitidis are capable of causing disease. Both of these species often asymptomatically colonize humans, a trait reminiscent of their commensal cousins. The factors that shift the balance between asymptomatic carriage and disease are unknown. Pathogenic Neisseria use retractile surface structures called Type IV pili to coordinate community behavior and to initiate and sustain infection. Previously, the contributions of pilus retraction have been studied by deleting the pilus retraction motor, PilT. Recent findings suggest the speed and force exerted by pilus retraction is responsive to environmental cues. By examining several PilT mutants that maintain the ability to retract pili, I show retraction, per se, is not required for N. gonorrhoeae social interactions with bacteria or with human cells. Furthermore, Type IV pilus retraction by the commensal N. elongata affects the host cell differently than retraction by N. gonorrhoeae. These observations collectively suggest pilus retraction properties shape the host cell response to Neisseria colonization and could tip the balance of asymptomatic colonization to symptomatic disease.

Thesis (M.S.)--University of Alabama at Birmingham, 2007. / Description based on contents viewed May 30, 2008; title from title screen. Includes bibliographical references (p. 31-43).

Saccharomyces cerevisiae V. P. I. Strain No. 1 was found to estimate the growth of Proteus vulgaris V. P. I. Strain No. 3 in a chemically-defined medium when growth curves of the viable counts of the two organisms in pure and in mixed culture were studied. The yeast stimulated the growth of the bacterium without its own numbers being affected, indicating a true commensalism. The stimulation began by the 8th hour of incubation and continued throughout the growth period. The organisms were plated on differential plating media designed to specifically permit the growth of one organism while inhibiting the other. The medium used for P. vulgaris contained bile salts to inhibit the yeast, while the medium used for S. cerevisiae contained penicillin to which the bacterium was sensitive. During the phase of active growth of the yeast, a temporary decrease or dip in viable count occurred to the extent of about 1/2 to 1 log unit, regardless of whether the yeast was in pure of mixed culture. Total counts of the yeast cells (by direct microscopic methods) failed to show any corresponding decrease. A rough correspondence of the appearance of amounts of ethanol detectable by gas chromatography in the medium was observed; however, the factors causing the viable count dip remain obscure. It is possible that clumping of yeast cells is closely connected with this dip. Separation of the yeast and bacterium by a dialysis membrane failed to halt the stimulatory action of the yeast. The ability of P. vulgaris to exhibit a growth response toward nicotinic acid, nicotinamide, or nicotinamide adenine dinucleotide was demonstrated, suggesting that the stimulatory factor formed by the yeast was a compound of this group. The amount of stimulatory factor formed by the yeast in pure culture after 48 hr corresponded to 0.20 µg of nicotinamide adenine dinucleotide/ml. Exhaustive attempts to identify the stimulatory factor by bioautography were unsuccessful; the amount of factor was too slight to be detectable by even this highly sensitive method. Evidence is presented to indicate that the high amount of biotin employed in the defined medium may have resulted in production of only small quantities of nicotinic acid-like factor in comparison to the amounts formed when less biotin was present. / Master of Science

ABSTRACTThis thesis situates the Harry Potter books into the greater body of food studies and into the extant children's literary tradition through an examination of how food can be used to understand cultural identity. Food is a biological need, but because we have created social rules and rituals around food consumption and sharing, there is more to eating than simple nutritional value. The Harry Potter series is as much about overcoming childhood adversity, and good versus evil, as it is about magic, and food in the Harry Potter series is both abundant and relevant to the narrative, context, and themes of the books. Sweets such as candy, puddings, and cakes, help construct both wizard and Muggle identity in addition to serving as a bridge between readers and characters. How the characters use sweets to create and reinforce friendships or exclude those who do not belong is important, especially since children usually lack other cultural capital and, in their worlds, food is reward, treat, and punishment. Examples of this are shown in the scene where Harry first travels on the Hogwarts Express, in the ways the Dursleys deny Harry birthday celebrations, and in how holidays are celebrated by the witches and wizards in the series.The sharing of food in the novels builds tensions, creates bonds, and codes different characters as "acceptable" or "unacceptable" based on their willingness, or refusal, to share food. Teatime and feasting are examples of how food is shared by analogous and disparate groups of people in the series. Tea is served most often by those in subordinate positions of power, but is one way in which the characters can socialize and create community. Feasts at the beginning and end of the school term bookmark the year by immersing students and faculty into a shared world at first, and then by sending them back to their families, aware of their own triumphs and accomplishments. When feasts are used to unite outside groups, such as before the Triwizard Tournament, the ways that different foods are embraced or rejected serve to reinforce identity and inclusion.Using cultural studies methods in conjunction with food studies and Reader-Response critical theory, this thesis argues that food in the Harry Potter series represents the socially constructed identities of the characters within the texts, and also serves to bridge the gap between the readers and the characters.

Le microbiote a un impact majeur sur la physiologie de son hôte, cependant notre compréhension des mécanismes régulant la relation hôte/microbiote reste limitée. Nous utilisons un hôte modèle simple, la Drosophile, afin de répondre à ces questions. Durant mon doctorat, je me suis attaché à une étape particulière du cycle de vie de la Drosophile, sa phase larvaire. Celle-ci constitue sa phase de croissance et est influencée par le contexte nutritionnel. Le microbiote influence également cette étape: l’association avec la bactérie Lactobacillus plantarum tempère les effets de la carence alimentaire en soutenant un taux de croissance élevé et une maturation rapide, en modulant chez l’hôte l’activité de l’hormone Ecdysone et de l’insuline. En retour, L.plantarum bénéficie de l’association, les larvesassurant sa persistance dans la niche (la niche étant le substrat nutritif, les larves et les bactéries associées). Pour caractériser les mécanismes mis en jeu dans ce mutualisme nous avons décrit les réponses transcriptomiques et métaboliques de la larve et avons également étudié les perturbations métaboliques de la niche. Nos résultats mettent en avant l’optimisation de l’extraction des acides aminés du substrat comme facteur clef du mutualisme. L.plantarum active l’expression des protéases intestinales de l’hôte via la voie IMD/NF-κB, et bénéficierait en retour d’une quantité d’acides aminés plus importante assurant sa persistance. Ainsi, nos travaux contribuent à l’effort de compréhension desmécanismes régulant l’interaction hôte/microbiote et pourraient conduire à de nombreuses applications thérapeutiques, notamment dans le cadre de déséquilibres nutritionnels. / Symbiotic bacterial populations (also called the “microbiota”) have a dramatic impact on their host’s physiology. However, our understanding of the mechanisms shaping host/microbes mutualism remains limited. We took advantage of Drosophila tractability to characterize the host’s and the microbial factors engaged in mutualism. During my PhD, I focused on the impact of the microbiota during the Drosophila larval phase, which constitutes its juvenile growth period. Drosophila larval phase is influenced by nutrition, but also by symbiotic microbes: specific association with the bacterium Lactobacillus plantarum buffers the deleterious effects of nutrient scarcity on the host’s juvenile growth, by sustaining greater growth rates and hastening maturation. L.plantarum mediate these effects by modulating the activity of the steroid hormone Ecdysone and the Insulin/Insulin-like Signaling pathway in its host. In return, L.plantarum benefits from Drosophila presence, as larvae ensure its long-term persistence in the niche (the niche being the nutritive substrate, the larvae and the bacteria dwelling on it). To characterize the mechanisms engaged in this mutualistic relationship, we described the host’s transcriptomic and metabolic responses to L.plantarum presence and characterized the metabolic perturbations occurring in the niche. Our results put forward the optimization of amino-acids extraction from the nutritive substrate as a cornerstone of mutualism. L.plantarum activates the expression of the host’s digestive proteases via IMD/NF-κB signaling and would benefit in return from an enhanced AA availability, which would help sustaining its long-term persistence. Altogether, our studies contribute to the understanding of the mechanisms regulating host/microbiota interaction and could lead to numerous therapeutic applications, notably aiming at counteracting the deleterious effects of nutritional imbalances.

Precise descriptions and comprehensive taxonomies of species and their ecology are essential in monitoring changes in marine biodiversity at multiple spatial scales. A currently undescribed species of commensal amphipod in the genus Leucothoe is reported from New Zealand, collected from the endemic tunicate Cnemidocarpa bicornuta. This species differs from others in the genus in having a one-articulate first maxilla palp and an apically produced tuberculate lobe on the inner margin of the outer plate of the maxilliped. Previous taxonomic surveys in New Zealand waters did not document this species, indicating that it may be a recent arrival. This research highlights the importance of biodiversity monitoring and taxonomic surveys to record occurrences of undescribed or recently-arrived taxa.

The coexistence of humans and rodents lasts from the beginnings of the history of agriculture. Many rodent populations accepted to synanthropic way of life and as commensals accompany human societies until today. In the first study we wanted to find out, how the evolution of non-commensal rodent species, a Cypriot mouse (Mus cypriacus), was influenced by people. This endemic island species evolved on the Cyprus Island without presence of any mammalian competitors or predators. In last 10.000 years humans arrived on the island, bringing several mammalian species, which affected the environment markedly. A black rat (Rattus rattus) is now dominant species there and presumably it is an important competitor for the Cypriot mouse. We supposed that the mice should avoid its odour. Nevertheless the rats odour was preferred by the mouse, probably as an odour of phylogenetically related species. On the contraty, the odour of domestic cat (species, which is also widespread on the island), was avoided. In conclusion, the long-term isolation from mammalian predators did not affect the antipredatory reactions of the Cypriot mouse. Our next study was focuse on changes in behavioural strategies of different populations of mice: the main question was how the commensal way of life affects their exploratory...