Pellicle ultrastructure demonstrates that Moyeria is a fossil euglenid

An earlier proposal of euglenid affinity for the acritarch Moyeria was based primarily on the pattern of bi-helical striate ornamentation as seen in scanning electron microscopy and light microscopy. Examination of specimens using transmission electron microscopy reveals that the ‘striae’ are actually integral components of the microfossil wall itself, corresponding to the pellicle strips of some euglenid species today. A Silurian specimen from Scotland preserves an articulated wall composed of thickened arches and thinner U-shaped interconnecting segments paralleling that seen in some modern photosynthetic euglenids. A second specimen from the Moyeria holotype section (Silurian of New York State) shows fused articulation, again compatible with some extant euglenids. This evidence is sufficient to transfer Moyeria out of the Incertae sedis group, Acritarcha, and into the Euglenida. This proposal helps establish the morphological basis for the recognition of euglenid microfossils and ultimately provides evidence of a lengthy fossil record of the eukaryotic supergroup Excavata

The Marine Microbial Eukaryote Transcriptome Sequencing Project (MMETSP): Illuminating the Functional Diversity of Eukaryotic Life in the Oceans through Transcriptome Sequencing

Microbial ecology is plagued by problems of an abstract nature. Cell sizes are so small and population sizes so large that both are virtually incomprehensible. Niches are so far from our everyday experience as to make their very definition elusive. Organisms that may be abundant and critical to our survival are little understood, seldom described and/or cultured, and sometimes yet to be even seen. One way to confront these problems is to use data of an even more abstract nature: molecular sequence data. Massive environmental nucleic acid sequencing, such as metagenomics or metatranscriptomics, promises functional analysis of microbial communities as a whole, without prior knowledge of which organisms are in the environment or exactly how they are interacting. But sequence-based ecological studies nearly always use a comparative approach, and that requires relevant reference sequences, which are an extremely limited resource when it comes to microbial eukaryotes

<i>Archaeperidinium saanichi</i> sp nov.: a new species based on morphological variation of cyst and theca within the <i>Archaeperidinium minutum</i> Jörgensen 1912 species complex

In this paper we describe a new species, Archaeperidinium saanichi sp. nov. within the Archaeperidinium minutum Jörgensen 1912 species complex. We examined the morphological variation of the cyst and motile stage by incubation experiments from sediment samples collected in coastal British Columbia (Canada), and compared it to closely related species. The theca of A. saanichi is differentiated from related species by overall size, the asymmetry of the intercalary plates and the right-sulcal plate (S.d.) not touching the cingulum. We provide a key to differentiate all closely related species. A. saanichi can be readily distinguished from A. minutum by a distinctively large cyst with a broad 2a type archeopyle and regularly spaced processes with relatively broad bases and aculeate process tips. Molecular phylogenetic analyses of large and small subunit (LSU and SSU) rDNA sequences demonstrated a close affinity of this species to A. minutum; however, the relatively high level of sequence conservation in dinoflagellate rDNA sequences made these particular markers inadequate for distinguishing one species from the other. Sediment-trap data suggest that A. saanichi has a preference for cooler temperatures and lowered salinities

Russell and Rubinstein's Pathology of Tumors of the Nervous System. Sixth Edition

An increasing number of parasites are being added to the list of those that can be transmitted via food or water and that pose a risk to human health if ingested. These zoonotic infections usually have complicated life cycles requiring a number of hosts for completion or a diversity of cycles of transmission that may interact. The challenge in all control efforts is to break the cycle of transmission that may lead to human infection, which requires the ability to detect and characterize the relevant parasite life cycle stage in food or water. This requires tools that are both sensitive and specific, and often beyond the limitations of conventional techniques such as microscopy