Association of RNase mitochondrial RNA processing enzyme with ribonuclease P in higher ordered structures in the nucleolus: a possible coordinate role in ribosome biogenesis.

RNase mitochondrial RNA processing enzyme (MRP) is a nucleolar ribonucleoprotein particle that participates in 5.8S ribosomal RNA maturation in eukaryotes. This enzyme shares a polypeptide and an RNA structural motif with ribonuclease P (RNase P), a nuclear endoribonuclease originally described in the nucleus that processes RNA transcripts to generate their mature 5' termini. Both enzymes are also located in mitochondria. This report further characterizes the relationship between RNase MRP and RNase P. Antisense affinity selection with biotinylated 2'-O-methyl oligoribonucleotides and glycerol gradient fractionation experiments demonstrated that small subpopulations of RNase MRP and RNase P associate with each other in vivo in macromolecular complex, possibly 60-80S preribosomes. This latter notion was supported by fluorescence in situ hybridization experiments with antisense oligonucleotides that localized that RNA components of RNase MRP and RNase P to the nucleolus and to discrete cytoplasmic structures. These findings suggest that small subpopulations of RNase MRP and RNase P are physically associated, and that both may function in ribosomal RNA maturation or ribosome assembly.

GABAergic feedforward projections from the inferior colliculus to the medial geniculate body.

A novel and robust projection from gamma-aminobutyric acid-containing (GABAergic) inferior colliculus neurons to the media] geniculate body (MGB) was discovered in the cat using axoplasmic transport methods combined with immunocytochemistry. This input travels with the classical inferior colliculus projection to the MGB, and it is a direct ascending GABAergic pathway to the sensory thalamus that may be inhibitory. This bilateral projection constitutes 10-30% of the neurons in the auditory tectothalamic system. Studies by others have shown that comparable input to the corresponding thalamic visual or somesthetic nuclei is absent. This suggests that monosynaptic inhibition or disinhibition is a prominent feature in the MGB and that differences in neural circuitry distinguish it from its thalamic visual and somesthetic counterparts.

Sterol regulation of acetyl coenzyme A carboxylase: a mechanism for coordinate control of cellular lipid.

Transcription from the housekeeping promoter for the acetyl coenzyme A carboxylase (ACC) gene, which encodes the rate-controlling enzyme of fatty acid biosynthesis, is shown to be regulated by cellular sterol levels through novel binding sites for the sterol-sensitive sterol regulatory element binding protein (SREBP)-1 transcription factor. The position of the SREBP sites relative to those for the ubiquitous auxiliary transcription factor Sp1 is reminiscent of that previously described for the sterol-regulated low density lipoprotein receptor promoter. The experiments provide molecular evidence that the metabolism of fatty acids and cholesterol, two different classes of essential cellular lipids, are coordinately regulated by cellular lipid levels.

Coordinate regulation of Bacillus subtilis peroxide stress genes by hydrogen peroxide and metal ions.

The Bacillus subtilis mrgA gene encodes an abundant DNA-binding protein that protects cells against the lethal effects of H2O2. Transcription of mrgA is induced by H2O2 or by entry into stationary phase when manganese and iron levels are low. We have selected for strains derepressed for transcription of mrgA in the presence of Mn(II). The resulting cis-acting mutants define an operator site just upstream of the mrgA promoter. Similar sequences flank the promoters for the catalase gene, katA, and the heme biosynthesis operon, hemAXCDBL. Like mrgA, transcription of the katA and hem genes is repressed by Mn(II), which thereby potentiates the killing action of H2O2. We identified two classes of trans-acting mutants derepressed for mrgA transcription in the presence of Mn(II): some exhibit a coordinate derepression of MrgA, catalase, heme biosynthesis, and alkyl hydroperoxide reductase and are H2O2 resistant, while others have reduced catalase activity and are H2O2 sensitive. These data indicate that the peroxide stress response of B. subtilis is regulated by a repressor that senses both metal ion levels and H2O2.

The impact of a future solar minimum on climate change projections in the Northern Hemisphere

Solar variability represents a source of uncertainty in the future forcings used in climate model simulations. Current knowledge indicates that a descent of solar activity into an extended minimum state is a possible scenario. With aid of experiments from a state-of-the-art Earth system model, we investigate the impact of a future solar minimum on Northern Hemisphere climate change projections. This scenario is constructed from recent 11 year solar-cycle minima of the solar spectral irradiance, and is therefore more conservative than the 'grand' minima employed in some previous modeling studies. Despite the small reduction in total solar irradiance (0.36 W m^-2), relatively large responses emerge in the winter Northern Hemisphere, with a reduction in regional-scale projected warming by up to 40%. To identify the origin of the enhanced regional signals, we assess the role of the different mechanisms by performing additional experiments forced only by irradiance changes at different wavelengths of the solar spectrum. We find that a reduction in visible irradiance drives changes in the stationary wave pattern of the North Pacific and sea-ice cover. A decrease in UV irradiance leads to smaller surface signals, although its regional effects are not negligible. These results point to a distinct but additive role of UV and visible irradiance in the Earth's climate, and stress the need to account for solar forcing as a source of uncertainty in regional scale projections.

On the Result of Invariance of the Closure Set of the Real Projections of the Zeros of an Important Class of Exponential Polynomials

In this paper we provide the proof of a practical point-wise characterization of the set RP defined by the closure set of the real projections of the zeros of an exponential polynomial P(z) = Σn j=1 cjewjz with real frequencies wj linearly independent over the rationals. As a consequence, we give a complete description of the set RP and prove its invariance with respect to the moduli of the c′ js, which allows us to determine exactly the gaps of RP and the extremes of the critical interval of P(z) by solving inequations with positive real numbers. Finally, we analyse the converse of this result of invariance.

Philadelphia, Pennsylvania (East), and vicinity, 1955 (Raster Image) (Image 1 of 2)

This layer is a georeferenced raster image of the United States Geological Survey sheet map set entitled: Philadelphia and vicinity, east, 1955 (and west, 1956) (Pennsylvania - New Jersey) by the Geological Survey. It was published in 1958. Scale 1:24,000. Covers Philadelphia and portions of adjacent counties. Mapped by the Geological Survey, U.S. Coast and Geodetic Survey and Army Map Service. Compiled from 1:24,000 scale maps of Langhorne 1953, Hatboro 1952, Ambler 1952, Germantown 1952, Frankford 1950, Beverly 1955, Moorestown 1953, Camden 1949, Philadelphia 1949, Woodbury 1949, Rennemede 1952, and Clementon 1953 7.5 minute quadrangles. This layer is image 1 of 2 total images of the two sheet source map set representing the eastern portion of the map. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Pennsylvania South State Plane Coordinate System NAD27 (in Feet) (Fipszone 3702). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. USGS maps are typical topographic maps portraying both natural and manmade features. They show and name works of nature, such as mountains, valleys, lakes, rivers, vegetation, etc. They also identify the principal works of humans, such as roads, railroads, boundaries, transmission lines, major buildings, etc. Relief is shown with standard contour intervals of 10 and 20 feet. Please pay close attention to map collar information on projections, spheroid, sources, dates, and keys to grid numbering and other numbers which appear inside the neatline. This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection as part of the Imaging the Urban Environment project. Maps selected for this project represent major urban areas and cities of the world, at various time periods. These maps typically portray both natural and manmade features at a large scale. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.

Philadelphia, Pennsylvania, 1983 (Raster Image)

This layer is a georeferenced raster image of the United States Geological Survey sheet map entitled: Philadelphia County, Pennsylvania, produced by the United States Geological Survey ; Commonwealth of Pennsylvania, Department of Environmental Resources, Topographic and Geologic Survey. It was published in 1983. Scale 1:50,000. Compiled from USGS 1:24,000-scale topographic maps. Planimetry revised from aerial photographs taken in 1981 and other source data. Revised information not field checked. Map edited 1982. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Pennsylvania South State Plane Coordinate System NAD27 (in Feet) (Fipszone 3702). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. USGS maps are typical topographic maps portraying both natural and manmade features. They show and name works of nature, such as mountains, valleys, lakes, rivers, vegetation, etc. They also identify the principal works of humans, such as roads, railroads, boundaries, transmission lines, major buildings, etc. Relief is shown with standard contour intervals of 20 feet and spot heights. Please pay close attention to map collar information on projections, spheroid, sources, dates, and keys to grid numbering and other numbers which appear inside the neatline. Includes notes, index to 1:24,000-scale maps, and location map. This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection as part of the Imaging the Urban Environment project. Maps selected for this project represent major urban areas and cities of the world, at various time periods. These maps typically portray both natural and manmade features at a large scale. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.

Philadelphia, Pennsylvania (West), and vicinity, 1956 (Raster Image) (Image 2 of 2)

This layer is a georeferenced raster image of the United States Geological Survey sheet map set entitled: Philadelphia and vicinity, east, 1955 (and west, 1956) (Pennsylvania - New Jersey) by the Geological Survey. It was published in 1958. Scale 1:24,000. Covers Philadelphia and portions of adjacent counties. Mapped by the Geological Survey and U.S. Coast and Geodetic Survey. Compiled from 1:24,000 scale maps of Ambler 1952, Lansdale 1951, Collegeville 1951, Valley Forge 1952, Norristown 1952, Germantown 1952, Philadelphia 1949, Lansdowne 1956, Media 1955, Marcus Hook 1953, Bridgeport 1953, and Woodbury 1949 1953 7.5 minute quadrangles. This layer is image 1 of 2 total images of the two sheet source map set representing the eastern portion of the map. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Pennsylvania South State Plane Coordinate System NAD27 (in Feet) (Fipszone 3702). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. USGS maps are typical topographic maps portraying both natural and manmade features. They show and name works of nature, such as mountains, valleys, lakes, rivers, vegetation, etc. They also identify the principal works of humans, such as roads, railroads, boundaries, transmission lines, major buildings, etc. Relief is shown with standard contour intervals of 10 and 20 feet. Please pay close attention to map collar information on projections, spheroid, sources, dates, and keys to grid numbering and other numbers which appear inside the neatline. This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection as part of the Imaging the Urban Environment project. Maps selected for this project represent major urban areas and cities of the world, at various time periods. These maps typically portray both natural and manmade features at a large scale. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.

Los Angeles, California (East), and vicinity, 1953 (Raster Image) (Image 1 of 2)

This layer is a georeferenced raster image of the United States Geological Survey sheep map set entitled: Los Angeles and vicinity, East [and West], California. Edition 1953. It was published in 1956. Compiled from 1:24,000 scale maps of the Azusa 1953, Mt. Wilson 1953, Pasadena 1953, Los Angeles 1953, El Monte 1953, Baldwin Park 1953, La Habra 1950, Whittier 1949, and South Gate 1952 7.5 minute quadrangles. Scale 1:24,000. This layer is image 1 of 2 total images of the two sheet source map set representing the eastern portion of the map set. The image inside the map neatline is georeferenced to the surface of the earth and fit to the California State Plane Zone V Coordinate System NAD27 (in Feet) (Fipszone 0405). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. USGS maps are typical topographic maps portraying both natural and manmade features. They show and name works of nature, such as mountains, valleys, lakes, rivers, vegetation, etc. They also identify the principal works of humans, such as roads, railroads, boundaries, transmission lines, major buildings, etc. Relief is shown with standard contour intervals of 5 and 25 feet. Please pay close attention to map collar information on projections, spheroid, sources, dates, and keys to grid numbering and other numbers which appear inside the neatline. This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection as part of the Imaging the Urban Environment project. Maps selected for this project represent major urban areas and cities of the world, at various time periods. These maps typically portray both natural and manmade features at a large scale. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.

Los Angeles, California (West), and vicinity, 1953 (Raster Image) (Image 2 of 2)

This layer is a georeferenced raster image of the United States Geological Survey sheep map set entitled: Los Angeles and vicinity, East [and West], California. Edition 1953. It was published in 1956. Compiled from 1:24,000 scale maps of the Burbank 1953, Van Nuys 1953, Canoga Park 1952, Topanga 1952, Beverly Hills 1950, Hollywood 1953, Inglewood 1952, and Venice 1950 7.5 minute quadrangles. Hydrography compiled from USC&GS Chart 5144. Scale 1:24,000. This layer is image 2 of 2 total images of the two sheet source map set representing the western portion of the map set. The image inside the map neatline is georeferenced to the surface of the earth and fit to the California State Plane Zone V Coordinate System NAD27 (in Feet) (Fipszone 0405). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. USGS maps are typical topographic maps portraying both natural and manmade features. They show and name works of nature, such as mountains, valleys, lakes, rivers, vegetation, etc. They also identify the principal works of humans, such as roads, railroads, boundaries, transmission lines, major buildings, etc. Relief is shown with standard contour intervals of 5 and 25 feet. Depth curves in feet. Please pay close attention to map collar information on projections, spheroid, sources, dates, and keys to grid numbering and other numbers which appear inside the neatline. This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection as part of the Imaging the Urban Environment project. Maps selected for this project represent major urban areas and cities of the world, at various time periods. These maps typically portray both natural and manmade features at a large scale. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.

San Francisco, California and vicinity, 1954 (Raster Image)

This layer is a georeferenced raster image of the United States Geological Survey sheet map entitled: San Francisco and vicinity, California, 1954. It was published in 1957. Scale 1:24,000. Compiled from 1:24,000 scale maps of the San Quentin 1947, San Rafael 1954, Point Bonita 1954, San Francisco North 1947, and San Francisco South 1947 7.5 minute quadrangles. Hydrography compiled from USC&GS charts 5532 and 5402. The image inside the map neatline is georeferenced to the surface of the earth and fit to the California Zone III State Plane Coordinate System NAD27 (in Feet) (Fipszone 0403). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map. USGS maps are typical topographic maps portraying both natural and manmade features. They show and name works of nature, such as mountains, valleys, lakes, rivers, vegetation, etc. They also identify the principal works of humans, such as roads, railroads, boundaries, transmission lines, major buildings, etc. Relief is shown with contour intervals 25 and 40 feet with supplementary contours at 5 and 20 foot intervals and spot heights. Please pay close attention to map collar information on projections, spheroid, sources, dates, and keys to grid numbering and other numbers which appear inside the neatline. This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection as part of the Imaging the Urban Environment project. Maps selected for this project represent major urban areas and cities of the world, at various time periods. These maps typically portray both natural and manmade features at a large scale. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.