The genes coding for 4 snRNAs of Drosophila melanogaster: localization and determination of gene numbers.

Four small nuclear RNAs (snRNAs) have been isolated from Drosophila melanogaster flies. They have been characterized by base analysis, fingerprinting, and injection into Axolotl oocytes. The size of the molecules and the modified base composition suggest that the following correlations can be made: snRNA1 approximately U2-snRNA; snRNA2 approximately U3-snRNA; snRNA3 approximately U4-snRNA; snRNA4 approximately U6-snRNA. The snRNAs injected into Axolotl oocytes move into the nuclei, where they are protected from degradation. The genes coding for these snRNAs have been localized by "in situ" hybridization of 125-I-snRNAs to salivary gland chromosomes. Most of the snRNAs hybridize to different regions of the genome: snRNA1 to the cytological regions 39B and 40AB; snRNA2 to 22A, 82E, and 95C; snRNA3 to 14B, 23D, 34A, 35EF, 39B, and 63A; snRNA4 to 96A. The estimated gene numbers (Southern-blot analysis) are: snRNA1:3; snRNA2:7; snRNA3:7; snRNA4:1-3. The gene numbers correspond to the number of sites labeled on the polytene salivary gland chromosomes.     

The nucleotide sequence of glutamate tRNA4 of Drosophila melanogaster.

The nucleotide sequence of Drosophila melanogaster glutamate tRNA4 was determined to be: pU-C-C-C-A-U-A-U-G-G-U-C-psi-A-G-D-G-G-C-D-A-G-G-A-U-A-U-C-U-G-G-C (m) -U-U-U-C-A-C-C-A-G-A-A-G-G-C-C-C-G-G-G-T-psi-U-C-G-A-U-U-C-C-C-G-G-U-A-U-G-G-G-A-A-C-C-AOH. A partial modified C is found at position 32 in the anticodon loop.     

Development and laboratory-scale testing of a fully automated online flow cytometer for drinking water analysis

Accurate and sensitive online detection tools would benefit both fundamental research and practical applications in aquatic microbiology. Here, we describe the development and testing of an online flow cytometer (FCM), with a specific use foreseen in the field of drinking water microbiology. The system incorporated fully automated sampling and fluorescent labeling of bacterial nucleic acids with analysis at 5-min intervals for periods in excess of 24 h. The laboratory scale testing showed sensitive detection (< 5% error) of bacteria over a broad concentration range (1 × 10(3) -1 × 10(6) cells mL(-1) ) and particularly the ability to track both gradual changes and dramatic events in water samples. The system was tested with bacterial pure cultures as well as indigenous microbial communities from natural water samples. Moreover, we demonstrated the possibility of using either a single fluorescent dye (e.g., SYBR Green I) or a combination of two dyes (SYBR Green I and Propidium Iodide), thus broadening the application possibilities of the system. The online FCM approach described herein has considerable potential for routine and continuous monitoring of drinking water, optimization of specific drinking water processes such as biofiltration or disinfection, as well as aquatic microbiology research in general.     

Hydratations- und Permeabilitätsstudien an unbefruchteten Fucus-Eiern (Fucus vesiculosus L.)

Ohne Zusammenfassung     

Beiträge zur Lichtkeimung von Amarantus caudatus L. und Phacelia tanacetifolia Benth

Ohne ZusammenfassungMit 10 Textabbildungen.     

Untersuchungen über die Symbiose von Tieren mit Pilzen und Bakterien

Ohne ZusammenfassungEs ist mir eine angenehme Pflicht, auch an dieser Stelle der Deutschen Forschungsgemeinschaft, mit deren Unterstützung die vorliegenden Untersuchungen durchgeführt wurden, meinen besten Dank auszusprechen. Zu besonderem Dank fühle ich mich Herrn Prof. Dr. W. Schwartz für die Anregung zu dieser Arbeit, für viele Ratschläge und alle erhaltene Förderung verpflichtet.     

Addition of Nitrogen Increases Variability of Vegetation Cover in an Arid System with Unpredictable Rainfall

Ecosystems - Addition of nitrogen (N) to rangeland that has been degraded through overgrazing or drought can hasten vegetation recovery. Additional N may influence temporal stability of vegetation...     

The effect of hexose ratios on metabolite production in Saccharomyces cerevisiae strains obtained from the spontaneous fermentation of mezcal

Mezcal from Tamaulipas (México) is produced by spontaneous alcoholic fermentation using Agave spp. musts, which are rich in fructose. In this study eight Saccharomyces cerevisiae isolates obtained at the final stage of fermentation from a traditional mezcal winery were analysed in three semi-synthetic media. Medium M1 had a sugar content of 100 g l^?1 and a glucose/fructose (G/F) of 9:1. Medium M2 had a sugar content of 100 g l^?1 and a G/F of 1:9. Medium M3 had a sugar content of 200 g l^?1 and a G/F of 1:1. In the three types of media tested, the highest ethanol yield was obtained from the glucophilic strain LCBG-3Y5, while strain LCBG-3Y8 was highly resistant to ethanol and the most fructophilic of the mezcal strains. Strain LCBG-3Y5 produced more glycerol (4.4 g l^?1) and acetic acid (1 g l^?1) in M2 than in M1 (1.7 and 0.5 g l^?1, respectively), and the ethanol yields were higher for all strains in M1 except for LCBG-3Y5, -3Y8 and the Fermichamp strain. In medium M3, only the Fermichamp strain was able to fully consume the 100 g of fructose l^?1 but left a residual 32 g of glucose l^?1. Regarding the hexose transporters, a high number of amino acid polymorphisms were found in the Hxt1p sequences. Strain LCBG-3Y8 exhibited eight unique amino acid changes, followed by the Fermichamp strain with three changes. In Hxt3p, we observed nine amino acid polymorphisms unique for the Fermichamp strain and five unique changes for the mezcal strains.     

Dynamic occupancy models for analyzing species' range dynamics across large geographic scales

Large‐scale biodiversity data are needed to predict species' responses to global change and to address basic questions in macroecology. While such data are increasingly becoming available, their analysis is challenging because of the typically large heterogeneity in spatial sampling intensity and the need to account for observation processes. Two further challenges are accounting for spatial effects that are not explained by covariates, and drawing inference on dynamics at these large spatial scales. We developed dynamic occupancy models to analyze large‐scale atlas data. In addition to occupancy, these models estimate local colonization and persistence probabilities. We accounted for spatial autocorrelation using conditional autoregressive models and autologistic models. We fitted the models to detection/nondetection data collected on a quarter‐degree grid across southern Africa during two atlas projects, using the hadeda ibis (Bostrychia hagedash) as an example. The model accurately reproduced the range expansion between the first (SABAP1: 1987–1992) and second (SABAP2: 2007–2012) Southern African Bird Atlas Project into the drier parts of interior South Africa. Grid cells occupied during SABAP1 generally remained occupied, but colonization of unoccupied grid cells was strongly dependent on the number of occupied grid cells in the neighborhood. The detection probability strongly varied across space due to variation in effort, observer identity, seasonality, and unexplained spatial effects. We present a flexible hierarchical approach for analyzing grid‐based atlas data using dynamical occupancy models. Our model is similar to a species' distribution model obtained using generalized additive models but has a number of advantages. Our model accounts for the heterogeneous sampling process, spatial correlation, and perhaps most importantly, allows us to examine dynamic aspects of species ranges.