Germ cell formation in Drosophila relies on polar granules, which are large ribonucleoprotein complexes found at the posterior end of the embryo. The granules undergo characteristic changes in morphology during development, including the assembly of multiple spherical bodies from smaller precursors. Several polar granule components, both protein and RNA, have been identified. One of these, the protein Oskar, acts to initiate granule formation during oogenesis and to recruit other granule components. To investigate whether Oskar has a continuing role in organization of the granules and control of their morphology, we took advantage of species-specific differences in polar granule structure. The polar granules of D. immigrans fuse into a single large oblong aggregate, as opposed to the multiple, distinct, spherical granules of D. melanogaster embryos. D. immigrans oskar rescues the body patterning and pole cell defects of embryos from D. melanogaster oskar(-) mothers, and converts the morphology of the polar granules to that of D. immigrans. The nuclear bodies, which are structures that appear to be closely related to polar granules, are also converted to the D. immigrans type morphology. We conclude that oskar plays a persistent and central role in the polar granules, not only initiating their formation but also controlling their organization and morphology.

Primordial germ cells (PGCs) form at the posterior pole of the Drosophila embryo, and then migrate to their final destination in the gonad where they will produce eggs or sperm. Studies of the different stages in this process, including assembly of germ plasm in the oocyte during oogenesis, specification of a subset of syncytial embryonic nuclei as PGCs, and migration, have been informed by genetic analyses. Mutants have defined steps in the process, and the identities of the affected genes have suggested biochemical mechanisms. Here we describe a novel PGC phenotype. When Neurl4 activity is reduced, newly formed PGCs frequently adopt irregular shapes and appear to bud off vesicles. PGC number is also reduced, an effect exacerbated by a separate role for Neurl4 in germ plasm formation during oogenesis. Like its mammalian homolog, Drosophila Neurl4 protein is concentrated in centrosomes and downregulates centrosomal protein CP110. Reducing CP110 activity suppresses the abnormal PGC morphology of Neurl4 mutants. These results extend prior analyses of Neurl4 in cultured cells, revealing a heightened requirement for Neurl4 in germ-line cells in Drosophila.

Abstract.Appalachian Corridor H will pass through Beaver Creek watershed in Tucker County, West Virginia. Some of this area has been affected by surface mining of Upper Freeport Coal. The resulting mined lands are currently producing acid mine drainage, and have the potential to produce more if disturbed. In order to document soil development and to predict impacts of disturbance on water quality, a study was initiated to evaluate properties of the minesoils that may be affected by highway construction. Six sampling sites were located on both minesoils and native soils, and both will be disturbed during road construction. Soil profiles were described and horizons were sampled for laboratory analysis. Analyses of pH; total carbon and sulfur; and acid-base accounting were completed for the soils. The pH values ranged from 3.2 to 5.0. Total sulfur was generally low, ranging from 0.01% to 0.64%. Several rock cores drilled along two proposed routes by a private firm were sampled and analyzed by acid-base accounting procedures. The cores indicated generally acidic rock units in this region and the potential of producing additional acidity if unweathered rocks and minesoils are exposed to the atmosphere. The minesoil and core data have been used to assist the West Virginia Division of Highways in locating the corridor through the mined areas.Additional

Abstract:Appalachian Corridor H will pass through Beaver Creek watershed in Tucker County, West Virginia. This is a sensitive area because numerous wetlands and reclaimed mined lands are located in the vicinity of the proposed highway. The West Virginia Division of Highways funded a project to assess the effects of the highway on the watershed. The two major coal beds in the watershed were Bakerstown, a member of the Conemaugh Formation, and Upper Freeport, a member of the Allegheny Formation. Bakerstown was mined and reclaimed in the 1970s, and Upper Freeport was mined and reclaimed in the 1960s. The dominant vegetation on the Bakerstown sites was grasses and legumes with scattered trees, while Upper Freeport sites were uniformly covered with red pine (Pinus resinosa Ait.). In order to document the existing conditions prior to the construction of the highway, a study was initiated to evaluate the properties and genesis of minesoils in the watershed. Six minesoil sampling points were located on Bakerstown sites and six were located on Upper Freeport sites. In addition, six sampling points were located on contiguous native soils. Soil profiles were described and horizons were sampled for laboratory physical and chemical analyses. The native soils were well drained to very poorly drained Inceptisols or Ultisols developed in alluvium or colluvium. Three of the six sampling points had fragipans. Minesoils developing on the Bakerstown sites had A horizons ranging from 3 to 16 cm thick. Sola of these soils ranged in thickness from 15 to 49 cm. Five of the six points had sola ranging from 15 to 33 cm thick. Minesoils on the Upper Freeport sites had A horizons that were 4 to 11 cm thick. Five of the six sampling points had sola ranging from 9 to 35 cm thick. One point had an uncommonly thick solum with Bw horizons described to 99 cm. Minesoils on both sites were classified as Entisols and Inceptisols. Although the depth of minesoil sola forming on the Upper Freeport and the Bakerstown sites was similar, fewer horizons were described per profile in Bakerstown minesoils. We attributed this horizonation difference to differences in parent materials. The rock fragments in Bakerstown minesoils were predominantly sandstones, whereas rock fragments in the Upper Freeport minesoils were a mixture of shale and sandstone.

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