St. Michael in the Arts

The objective of this thesis is to gather together under one cover samples of the many ways St. Michael is portrayed by creative artists in various locales and at different periods of time. The first chapter is a condensation of the literature used for the study showing the characteristics attributed to St. Michael. He is portrayed as an Archangel existing in Heaven as the militant leader of the angels of God. He is purported to have appeared on earth as messenger of God, and is often considered judge and caretaker of man\u27s soul after death. St. Michael is to have existed prior to the creation of the world and is scheduled to reappear at the end of the world. Chapter two contains selected photographic reproductions of twenty works of visual art including drawings, paintings, and sculpture. The works range from classic art to folk art from such generally well-known artists as Raphael and Dürer to relatively obscure and unknown artists. The variety of works cover a period of time from the tenth to the twentieth centuries in Asia, Europe, and America. In the third chapter music that has been composed with St. Michael as its inspiration is shown. A cantata, an organ solo, a vocal trio, a children\u27s song, hymnody, and portions of liturgical services were selected as examples. Literature that refers to the Archangel is discussed in chapter four. St. Michael is mentioned in biblical, apocryphal, and apocalyptic literature. He is included in some of the works of Milton, Yeats, and Longfellow and, in addition, is a useful topic for more contemporary writings

The Distribution of Cadmium, Chromium and Lead in Crabs, Clams and Oysters from Calcasieu Estuary, Louisiana

In November 1978, specimens of oysters (Crassostrea virginica), clams (Rangia cuneata), crabs (Callinectes sapidus) and water and sediment samples were collected from Calcasieu Estuary, Louisiana. The concentrations of cadmium, chromium and lead were determined in the samples with an inductively coupled argon plasma direct reading emission spectrophotometer. Crab claw muscle, gill and carapace tissues were analyzed separately. Oysters and clams were separated into shell and whole soft tissue samples which were analyzed separately. The concentration order of the metals in crab carapace and in oyster shells was similar to that of the sediments, (Pb\u3eCr\u3eCd). The sediments and exoskeletons seem to be indicative of long-term conditions and/or of an adsorptive concentrating mechanism being present. Concentration order of the metals in water samples, in crab claw muscle and gill tissues, and in clam whole soft tissues were similar (Cr\u3ePb\u3eCd). These findings suggest that soft tissues of clams and crabs are indicative of the short-term availability of these metals to the biota and/or the presence of an absorptive concentration mechanism. It was expected that oyster soft tissues would provide similar results, however, they did not. Results show that C. sapidus, R. cuneata and C. virginica don\u27t concentrate cadmium, chromium and lead uniformly in all anatomical body regions. Concentration of these metals seemed to be evident in the estuarine food chain in which crabs, in most cases, concentrated metals to greater extents than did clams and oysters. The possibility of a synergistic mechanism concentrating metals in each species was noted. Concentrations of cadmium, chromium and lead were independent of body weights

The effect of host heterogeneity and parasite intragenomic interactions on parasite population structure

Understanding the processes that shape the genetic structure of parasite populations and the functional consequences of different parasite genotypes is critical for our ability to predict how an infection can spread through a host population and for the design of effective vaccines to combat infection and disease. Here, we examine how the genetic structure of parasite populations responds to host genetic heterogeneity. We consider the well-characterized molecular specificity of major histocompatibility complex binding of antigenic peptides to derive deterministic and stochastic models. We use these models to ask, firstly, what conditions favour the evolution of generalist parasite genotypes versus specialist parasite genotypes? Secondly, can parasite genotypes coexist in a population? We find that intragenomic interactions between parasite loci encoding antigenic peptides are pivotal in determining the outcome of evolution. Where parasite loci interact synergistically (i.e. the recognition of additional antigenic peptides has a disproportionately large effect on parasite fitness), generalist parasite genotypes are favoured. Where parasite loci act multiplicatively (have independent effects on fitness) or antagonistically (have diminishing effects on parasite fitness), specialist parasite genotypes are favoured. A key finding is that polymorphism is not stable and that, with respect to functionally important antigenic peptides, parasite populations are dominated by a single genotype

Parasitylenchus nearcticus sp.n. (Tylenchida : Allontonematidae) parasitizing Drosophila (Diptera : Drosophilidae) in North America

#Parasitylenchus nearticus sp. n. (#Tylenchida : #Allantonematidae) est décrit comme parasite de #Drosophila recens (#Diptera : #Drosophilidae) récolté dans les Adirondacks Moutains, Etat de New York, Etats-Unis d'Amérique. Cette nouvelle espèce est comparée à la seule espèce connue - en Grande-Bretagne - du genre #Parasitylenchus, et une clé des #Allantonematidae parasites de #Drosophilidae est présentée. Les femelles des deux générations parasites montrent un dimorphisme dans la forme du stylet et des glandes pharyngiennes. #P. nearcticus sp. n. stérilise les femelles de #D. recens$, ayant ainsi un impact sur l'écologie des populations de son hôte. (Résumé d'auteur

Parasites lead to evolution of robustness against gene loss in host signaling networks

Many biological networks can maintain their function against single gene loss. However, the evolutionary mechanisms responsible for such robustness remain unclear. Here, we demonstrate that antagonistic host–parasite interactions can act as a selective pressure driving the emergence of robustness against gene loss. Using a model of host signaling networks and simulating their coevolution with parasites that interfere with network function, we find that networks evolve both redundancy and specific architectures that allow them to maintain their response despite removal of proteins. We show that when the parasite pressure is removed, subsequent evolution can lead to loss of redundancy while architecture-based robustness is retained. Contrary to intuition, increased parasite virulence hampers evolution of robustness by limiting the generation of population level diversity in the host. However, when robustness emerges under high virulence, it tends to be stronger. These findings predict an increased presence of robustness mechanisms in biological networks operating under parasite interference. Conversely, the presence of such mechanisms could indicate current or past parasite interference

Temperature is a common climatic descriptor of lachryphagous activity period in Phortica variegata (Diptera: Drosophilidae) from multiple geographical locations

Background: The drosophilid Phortica variegata is known as vector of Thelazia callipaeda, the oriental eyeworm native to Asia that has become an emergent zoonotic agent in several European regions. Unlike almost all other arthropod vectors of pathogens, only P. variegata males feed of lachrymal secretions of animals, ingesting first-stage larvae (L1) of the worm living in the orbital cavities of the host, and allowing with the same behaviour the introduction of infective L3. Despite the increased detection of T. callipaeda in many European countries, information about the length of the lachryphagous activity period of P. variegata and a deep knowledge of the environmental and climatic variables involved are still limited. Methods: We herein present the results of a multicentre study involving five sites from four different countries (Italy, Spain, UK and USA) where canine thelaziosis is endemic and/or where it has already been ascertained the presence of P. variegata. Field data have been obtained on a fortnightly basis from mid-April to the end of November 2018 from a contemporary standardized sampling (same sampling effort and time of collection in all sites) of lachryphagous flies collected around the eyes of a human bait using an entomological net. These data have been associated to data collection of local climatic variables (day length, temperature, wind speed, barometric pressure and relative humidity). Results: Overall, a total of 4862 P. variegata flies (4637 males and 224 females) were collected, with high differences in densities among the different sampling sites. Significant positive correlations were found between P. variegata male density and temperature and wind speed, while negative correlations were observed for barometric pressure and relative humidity. However, the above significant differences are confirmed in each sampling site separately only for the temperature. Conclusions: This multicentre study highlights that temperature is the major common environmental driver in describing the lachryphagous activity of P. variegata in Europe and USA and, therefore, the transmission risk of thelaziosis.[Figure not available: see fulltext.

Wolbachia do not live by reproductive manipulation alone: infection polymorphism in Drosophila suzukii and D. subpulchrella

This is the peer reviewed version of the following article: Hamm, C. A., Begun, D. J., Vo, A., Smith, C. C. R., Saelao, P., Shaver, A. O., Jaenike, J. and Turelli, M. (2014), Wolbachia do not live by reproductive manipulation alone: infection polymorphism in Drosophila suzukii and D. subpulchrella. Mol Ecol, 23: 4871–4885. doi:10.1111/mec.12901, which has been published in final form at http://doi.org/10.1111/mec.12901. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.Drosophila suzukii recently invaded North America and Europe. Populations in Hawaii, California, New York and Nova Scotia are polymorphic for Wolbachia, typically with <20% infection frequency. The Wolbachia in D. suzukii, denoted wSuz, is closely related to wRi, the variant prevalent in continental populations of D. simulans. wSuz is also nearly identical to Wolbachia found in D. subpulchrella, plausibly D. suzukii's sister species. This suggests vertical Wolbachia transmission through cladogenesis (“cladogenic transmission”). The widespread occurrence of 7-20% infection frequencies indicates a stable polymorphism. wSuz is imperfectly maternally transmitted, with wild infected females producing on average 5-10% uninfected progeny. As expected from its low frequency, wSuz produces no cytoplasmic incompatibility (CI), i.e., no elevated embryo mortality when infected males mate with uninfected females, and no appreciable sex-ratio distortion. The persistence of wSuz despite imperfect maternal transmission suggests positive fitness effects. Assuming a balance between selection and imperfect transmission, we expect a fitness advantage on the order of 20%. Unexpectedly, Wolbachia-infected females produce fewer progeny than do uninfected females. We do not yet understand the maintenance of wSuz in D. suzukii. The absence of detectable CI in D. suzukii and D. subpulchrella makes it unlikely that CI-based mechanisms could be used to control this species without transinfection using novel Wolbachia. Contrary to their reputation as horizontally transmitted reproductive parasites, many Wolbachia infections are acquired through introgression or cladogenesis and many cause no appreciable reproductive manipulation. Such infections, likely to be mutualistic, may be central to understanding the pervasiveness of Wolbachia among arthropods