No description available.

The host-parasite interface between the branchiobdellid Cambarincola vitrea Ellis and its crayfish host is investigated along ecological, ultrastructural, serological, and endocrinological lines of evidence. Monthly analysis of a natural branchiobdellid from a vernal habitat demonstrates the annelid to be particularly sensitive to changes involving both the physical habitat as well as the host crayfish.

No description available.

An evaluation of host-plant resistance to the wireworm-Diabrotica-Systena (WDS) complex of root-feeding insects in sweetpotatoes was performed on a total of 15 cultivars and advanced lines over the course of 4 years (2017-2020). It was found that sweetpotatoes varieties can differ significantly in amount of damage incurred. Several mechanisms of resistance were proposed and tested: periderm toughness, dry weight percentage, and volatile organic chemical defenses. No significant difference was found amongst the varieties tested concerning the physical properties. Chemical analysis was limited in scope but did show some differences between a susceptible variety when compared to a resistant variety in the volatile chemical composition of the foliage. Finally, a commercial kairomone lure with sticky card for Diabroticites was tested for efficacy when compared to sweep net sampling throughout the season. No correlation could be found amongst the methods in terms of number and species of insects caught by each.

Cellular metabolic and immune pathways can be acted upon by diverse molecular factors. Some examples include small molecules, regulatory proteins or RNAs, intermediary metabolites and hormones. These factors can also be introduced or induced by pathogens during infections. Indeed, it is known that complex interplay exists between metabolism and immunity. However, the ways in which these interactions occur, and the nature of the players are active subjects of research. Herein, three different studies are presented which investigate the roles of three distinct modulators of metabolism and/or immunity. Firstly, a natural product produced by a pathogenic fungus is shown to activate the aryl hydrocarbon receptor and induce the expression of xenobiotic metabolizing enzymes. Secondly, the modulation of lipid metabolism by an immunometabolic antiviral microRNA, microRNA-185, is deconvoluted using activity-based protein profiling (ABPP), transcriptomic and lipidomic analysis. This study also identifies a novel enzymatic target of microRNA-185 which can be targeted pharmacologically to reduce hepatitis C virus infectivity. Finally, a third study investigates the link between a poorly characterized enzyme, lysophospholipase-like 1 (LYPLAL1), and hepatic glucose metabolism using a specific activity-based probe. Overall, the work presented in this thesis makes use of various molecular and chemical biology methods to probe pathways which are acted upon by structurally diverse factors to improve our understanding of host-pathogen interactions and metabolism.

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No description available.

No description available.

This thesis addresses the threat that personal computer faced from malware when the personal computer is connected to the Internet. Traditional host-based security approaches, such as anti-virus scanning protect the host from virus, worms, Trojans and other malwares. One of the issues of the host-based security approaches is that when the operating system is compromised by the malware, the antivirus software also becomes vulnerable. In this thesis, we present a novel approach through using an external device to enhance the host security by offloading the security solution from the host to the external device. We describe the design of the DeviceGuard framework that separate the security solution from the host and offload it to the external device, a Trusted Device. The architecture of the DeviceGuard consists of two components, the DeviceGuard application on the Trusted Device and a DeviceGuard daemon on the host. Our prototype based on Android Development Phone (ADP) shows the feasibilities and efficiency of our approach to provide security features including system file and user data integrity monitoring, secure signing and secure decryption. We use Bluetooth as the communication protocol between the host and the Trusted Device. Our experiment results indicates a practical Bluetooth throughput at about 2M Bytes per second is sufficient for short range communication between the host and the Trusted Device; Message digest with SHA-512, digital signing with 1024 bits signature and secure decryption with AES 256 bits on the Trusted device takes only the scale of 10? and 10? ms for 1K bytes and 1M bytes respectively which are also shows the feasibility and efficiency of the DeviceGuard solution. We also investigated the use of embedded system as the Trusted Device. Our solution takes advantage of the proliferation of devices, such as Smartphone, for stronger system and data security. / Master of Science

Comparative analysis of multiple genomes presents many challenges ranging from management of information about thousands of local similarities to definition of features by combination of evidence from multiple analyses and experiments. This research represents the development stage of a database-backed pipeline for comparative analysis of multiple genomes. The genomes of three recently sequenced species of Brucella were compared and a superset of known and hypothetical coding sequences was identified to be used in design of a discriminatory genomic cDNA array for comparative functional genomics experiments. Comparisons were made of coding regions from the public, annotated sequence of B. melitensis (GenBank) to the annotated sequence of B. suis (TIGR) and to the newly-sequenced B. abortus (personal communication, S. Halling, National Animal Disease Center, USDA). A systematic approach to analysis of multiple genome sequences is described including a data model for storage of defined features is presented along with necessary descriptive information such as input parameters and scores from the methods used to define features. A collection of adjacency relationships between features is also stored, creating a unified database that can be mined for patterns of features which repeat among or within genomes. The biological utility of the data model was demonstrated by a detailed analysis of the multiple genome comparison used to create the sample data set. This examination of genetic differences between three Brucella species with different virulence patterns and host preferences enabled investigation of the genomic basis of virulence. In the B. suis genome, seventy-one differentiating genes were found, including a contiguous 17.6 kb region unique to the species. Although only one unique species-specific gene was identified in the B. melitensis genome and none in the B. abortus genome, seventy-nine differentiating genes were found to be present in only two of the three Brucella species. These differentiating features may be significant in explaining differences in virulence or host specificity. RT-PCR analysis was performed to determine whether these genes are transcribed in vitro. Detailed comparisons were performed on a putative B. suis pathogenicity island (PAI). An overview of these genomic differences and discussion of their significance in the context of host preference and virulence is presented. / Master of Science