Zebrafish: a vertebrate tool for studying basal body biogenesis, structure, and function.

Understanding the role of basal bodies (BBs) during development and disease has been largely overshadowed by research into the function of the cilium. Although these two organelles are closely associated, they have specific roles to complete for successful cellular development. Appropriate development and function of the BB are fundamental for cilia function. Indeed, there are a growing number of human genetic diseases affecting ciliary development, known collectively as the ciliopathies. Accumulating evidence suggests that BBs establish cell polarity, direct ciliogenesis, and provide docking sites for proteins required within the ciliary axoneme. Major contributions to our knowledge of BB structure and function have been provided by studies in flagellated or ciliated unicellular eukaryotic organisms, specifically Tetrahymena and Chlamydomonas. Reproducing these and other findings in vertebrates has required animal in vivo models. Zebrafish have fast become one of the primary organisms of choice for modeling vertebrate functional genetics. Rapid ex-utero development, proficient egg laying, ease of genetic manipulation, and affordability make zebrafish an attractive vertebrate research tool. Furthermore, zebrafish share over 80 % of disease causing genes with humans. In this article, we discuss the merits of using zebrafish to study BB functional genetics, review current knowledge of zebrafish BB ultrastructure and mechanisms of function, and consider the outlook for future zebrafish-based BB studies

The Plastid Genome of Eutreptiella Provides a Window into the Process of Secondary Endosymbiosis of Plastid in Euglenids

Euglenids are a group of protists that comprises species with diverse feeding modes. One distinct and diversified clade of euglenids is photoautotrophic, and its members bear green secondary plastids. In this paper we present the plastid genome of the euglenid Eutreptiella, which we assembled from 454 sequencing of Eutreptiella gDNA. Comparison of this genome and the only other available plastid genomes of photosynthetic euglenid, Euglena gracilis, revealed that they contain a virtually identical set of 57 protein coding genes, 24 genes fewer than the genome of Pyramimonas parkeae, the closest extant algal relative of the euglenid plastid. Searching within the transcriptomes of Euglena and Eutreptiella showed that 6 of the missing genes were transferred to the nucleus of the euglenid host while 18 have been probably lost completely. Euglena and Eutreptiella represent the deepest bifurcation in the photosynthetic clade, and therefore all these gene transfers and losses must have happened before the last common ancestor of all known photosynthetic euglenids. After the split of Euglena and Eutreptiella only one additional gene loss took place. The conservation of gene content in the two lineages of euglenids is in contrast to the variability of gene order and intron counts, which diversified dramatically. Our results show that the early secondary plastid of euglenids was much more susceptible to gene losses and endosymbiotic gene transfers than the established plastid, which is surprisingly resistant to changes in gene content

Erosion and illegibility of images: ‘beyond the immediacy of the present’

The focus of this special journal issue ‘Erosion and Illegibility of Images’ is to explore the relationship of erosion and visibility through contemporary artistic practices at a moment when everything, as Latour suggests, is smashed to pieces. The essays in this issue deploy the notion of erosion as a conceptual tool in order to explore the shifting and depositing of materials, which is observed both on a formal visual level (the breaking up of the image surface) and a critical revaluation of memory, visibility and artistic tools. From an instrumentalist understanding of tools and material, I set out to explore the impact of a radical restriction and limitation of traditional skills and craftsmanship on the artistic process. While recent research has focused predominantly on art theoretical understandings of ruins, the articles collected here aim to interrogate the relationship between artists, artistic tools and the materials of production in contemporary artistic practice by putting them in conversation with each other and scrutinizing interventions such as ‘preservation’, remaking, retro-recuperations and nostalgia work of several kinds

Origins of cellular geometry

Cells are highly complex and orderly machines, with defined shapes and a startling variety of internal organizations. Complex geometry is a feature of both free-living unicellular organisms and cells inside multicellular animals. Where does the geometry of a cell come from? Many of the same questions that arise in developmental biology can also be asked of cells, but in most cases we do not know the answers. How much of cellular organization is dictated by global cell polarity cues as opposed to local interactions between cellular components? Does cellular structure persist across cell generations? What is the relationship between cell geometry and tissue organization? What ensures that intracellular structures are scaled to the overall size of the cell? Cell biology is only now beginning to come to grips with these questions

Factors affecting particleboard pressing time : interaction with catalyst systems /

Cover title.Includes bibliographical references.Mode of access: Internet

Chromatin Clumping in Mature Leukocytes: A Hitherto Unrecognized Abnormality

Abstract A 62-year-old man and a 73-year-old woman were found to have a nuclear abnormality characterized by exaggerated clumping of the chromatin in the mature granulocytic and erythroid cells. The mature granulocytes showed loss of normal segmentation. The abnormality was not noted in other family members and appeared to be related to an atypical leukemic process. The nuclear abnormality was shown to be associated with a defect in cellular production within the marrow. Granulocyte precursors and normoblasts incorporated 3H-TdR but did not divide. Electron microscopy suggested the distribution of more than normal quantities of heterochromatin to mature leukocytes. Ferrokinetic studies disclosed ineffective erythropoiesis. The sharing of this abnormality by the myeloid and erythroid cells suggests a common stem cell origin. A functional defect of phagocytosis and cellular aggregation was demonstrated in the neutrophils, but bacterial killing was not affected. The nuclear anomaly described herein may be a pre-leukemic abnormality. Since this paper was submitted for publication, we have treated two more patients with an identical nuclear defect; an 82-year-old woman and a 79-year-old man. The woman succumbed of acute leukemic transformation, while the man is still alive.</jats:p

Weathering characteristics of particleboard /

Caption title.Includes bibliographical references.Mode of access: Internet