Multiple Independent Origins of Apicomplexan-Like Parasites

The apicomplexans are a group of obligate animal pathogens that include Plasmodium (malaria), Toxoplasma (toxoplasmosis), and Cryptosporidium (cryptosporidiosis) [1]. They are an extremely diverse and specious group but are nevertheless united by a distinctive suite of cytoskeletal and secretory structures related to infection, called the apical complex, which is used to recognize and gain entry into animal host cells. The apicomplexans are also known to have evolved from free-living photosynthetic ancestors and retain a relict plastid (the apicoplast), which is non-photosynthetic but houses a number of other essential metabolic pathways [2]. Their closest relatives include a mix of both photosynthetic algae (chromerids) and non-photosynthetic microbial predators (colpodellids) [3]. Genomic analyses of these free-living relatives have revealed a great deal about how the alga-parasite transition may have taken place, as well as origins of parasitism more generally [4]. Here, we show that, despite the surprisingly complex origin of apicomplexans from algae, this transition actually occurred at least three times independently. Using single-cell genomics and transcriptomics from diverse uncultivated parasites, we find that two genera previously classified within the Apicomplexa, Piridium and Platyproteum, form separately branching lineages in phylogenomic analyses. Both retain cryptic plastids with genomic and metabolic features convergent with apicomplexans. These findings suggest a predilection in this lineage for both the convergent loss of photosynthesis and transition to parasitism, resulting in multiple lineages of superficially similar animal parasites

Characterization of new cristamonad species from kalotermitid termites including a novel genus, Runanympha

Cristamonadea is a large class of parabasalian protists that reside in the hindguts of wood-feeding insects, where they play an essential role in the digestion of lignocellulose. This group of symbionts boasts an impressive array of complex morphological characteristics, many of which have evolved multiple times independently. However, their diversity is understudied and molecular data remain scarce. Here we describe seven new species of cristamonad symbionts from Comatermes, Calcaritermes, and Rugitermes termites from Peru and Ecuador. To classify these new species, we examined cells by light and scanning electron microscopy, sequenced the symbiont small subunit ribosomal RNA (rRNA) genes, and carried out barcoding of the mitochondrial large subunit rRNA gene of the hosts to confirm host identification. Based on these data, five of the symbionts characterized here represent new species within described genera: Devescovina sapara n. sp., Devescovina aymara n. sp., Macrotrichomonas ashaninka n. sp., Macrotrichomonas secoya n. sp., and Macrotrichomonas yanesha n. sp. Additionally, two symbionts with overall morphological characteristics similar to the poorly-studied and probably polyphyletic ‘joeniid’ Parabasalia are classified in a new genus Runanympha n. gen.: Runanympha illapa n. sp., and Runanympha pacha n. sp

Molecular characterization and phylogeny of four new species of the genus Trichonympha (Parabasalia, Trichonymphea) from lower termite hindguts

Members of the genus Trichonympha are among the most well-known, recognizable and widely distributed parabasalian symbionts of lower termites and the wood-eating cockroach species of the genus Cryptocercus. Nevertheless, the species diversity of this genus is largely unknown. Molecular data have shown that the superficial morphological similarities traditionally used to identify species are inadequate, and have challenged the view that the same species of the genus Trichonympha can occur in many different host species. Ambiguities in the literature, uncertainty in identification of both symbiont and host, and incomplete samplings are limiting our understanding of the systematics, ecology and evolution of this taxon. Here we describe four closely related novel species of the genus Trichonympha collected from South American and Australian lower termites: Trichonympha hueyi sp. nov. from Rugitermes laticollis, Trichonympha deweyi sp. nov. from Glyptotermes brevicornis, Trichonympha louiei sp. nov. from Calcaritermes temnocephalus and Trichonympha webbyae sp. nov. from Rugitermes bicolor. We provide molecular barcodes to identify both the symbionts and their hosts, and infer the phylogeny of the genus Trichonympha based on small subunit rRNA gene sequences. The analysis confirms the considerable divergence of symbionts of members of the genus Cryptocercus, and shows that the two clades of the genus Trichonympha harboured by termites reflect only in part the phylogeny of their hosts

The phylogeny and evolution apicomplexan parasites

Apicomplexans are a large phylum of obligate animal parasites that contain pathogens such as Plasmodium spp. (the causative agent of malaria) and Toxoplasma gondii. While these medically relevant apicomplexans are the subject of extensive research, the bulk of the diversity of the group, particularly the lineages that infect invertebrates, remain poorly studied and largely ignored in high-throughput sequencing surveys. In this dissertation, I show that these groups are critical to gaining insights into the origins and evolution of the Apicomplexa. I begin by examining the diversity and inferred ecology of the enigmatic apicomplexan-related lineages (ARLs), and show that ARL-V is highly abundant in environmental surveys, and is tightly associated with coral tissue and mucus, suggesting that it represents a core symbiont of coral. In the following chapters, using methods of single-cell transcriptomics, I sequenced the transcriptomes of 15 invertebrate-infecting apicomplexans. Using this dataset, I constructed a robust and taxon-rich multi-gene apicomplexan phylogeny that resolves the deep phylogenetic relationships within the group, and also form a new class of apicomplexans, the Marosporida, that is sister to the Hematozoa and Coccidia. Most unexpectedly, in Chapter 2, I show that certain taxa previously classified as apicomplexans, actually represent convergently evolved animal parasites, suggesting that apicomplexan-like parasites have evolved at least four times independently. In Chapter 3, I examine the presence and function of apicoplasts (remnant plastids) across the diversity of the group using whole genome shotgun sequencing (WGS), and find that the Marosporida contain the smallest, most AT-rich, and gene poor apicoplast genomes sequenced to date. I also present the first evidence of plastids in the gregarines, and show that archigregarines retain the canonical apicomplexan plastid metabolism, whereas only one clade of marine eugregarines retains plastids that solely carry out type II fatty acid biosynthesis. Lastly in Chapter 4, I reconstruct the mitochondrial metabolism in the gregarines and squirmids, and find that eugregarines contain highly reduced respiratory chains, suggesting that they have lost their mitochondrial genomes, and possess limited energy metabolism. Altogether, the data presented here, illustrates the significance of invertebrate-infecting apicomplexans in illuminating the early evolution of the apicomplexans and myzozoans.Science, Faculty ofBotany, Department ofGraduat

A computational complexity-aware model for performance analysis of software servers

Queueing models are routinely used to analyze the performance of software systems. However, contrary to common assumptions, the time that a software server takes to complete jobs may depend on the total number of active sessions in the server. In this paper, we present a queueing model that explicitly takes into account the time, taken by algorithms in the server, that varies with the user population. The model analytically predicts the response time and the "saturation number" of such systems. We validate our model with simulation and further demonstrate its usefulness by suggesting a heuristic technique to "discover" the complexity of algorithms in server software, solely from response time measurement. We applied the discovery technique to a Web-server test-bed, and found that we can identify the asymptotic behavior of processing time as a function of the user population with a fair amount of accuracy. The results show that this promises to be one of the many "black-box analysis" techniques, often found necessary in the real world.© IEE

A combined LIFOpriority scheme for overload control of e-Commerce web servers

E-commerce Web-servers often face overload conditions during which revenue-generating requests may be dropped or abandoned due to an increase in the browsing requests. In this paper we present a simple, yet effective, mechanism for overload control of E-commerce Web-servers. We develop an E-commerce workload model that separates the browsing requests from revenue-generating transaction requests. During overload, we apply LIFO discipline in the browsing queues and use a dynamic priority model to service them. The transaction queues are given absolute priority over the browsing queues. This is called the LIFO-Pri scheduling discipline. Experimental results show that LIFO-Pri dramatically improves the overall Web-server throughput while also increasing the completion rate of revenue-generating requests. The Web-server was able to operate at nearly 60 % of its maximum capacity even when offered load was 1.5 times its capacity. Further, when compared to a single queue FIFO system, there was a seven-fold increase in the number of completed revenue-generating requests during overload. Keywords: E-commerce, overload control, Web-servers, LIFO, priority. 1

Anesthesia management of

Sturge-Weber Syndrome (SWS) is a non-familial neurocutaneous disorder characterized by facial port wine stain and occipital leptoangiomatosis with resulting neurological abnormalities. Ocular involvement is seen in 25–30% cases. We report a case of 12 year old boy having port wine stain on his left side of face with poor left sided vision. Proper examination and anesthetic management of these patients are very important for an anticipated difficult intubation if angiomas involve the airway. Smooth induction and extubation are necessary to avoid increase in intraocular and intracranial pressure