Ornithologische Notizen aus dem Ebrodelta

Zusammenfassung Im Ebrodelta ist, abgesehen von einigen Seen und Sümpfen, nur noch ein schmaler Küstenstreifen landwirtschaftlich ungenutzt. Hier hat sich ein Teil ursprünglichen Vogelreichtums erhalten, und hier wurde seit einigen Jahren eine Reihe faunistischer Erhebungen durchgeführt.Diese erbrachten mehrere erste Brutnachweise für Spanien oder die spanische Mittelmeerküste:Larus ridibundus, Sterna dougallii, St. sandvicensis, Haematopus ostralegus, Limosa limosa, Asio flammeus, Acrocephalus palustris. Als Rast- und Überwinterungsgebiet ist das Delta von großer Bedeutung, z. B. fürEgretta garzetta undPhoenicopterus ruber. Enge Beziehungen zur Camargue sind vielfach erkennbar, vielleicht sogar hinsichtlich der Ausbreitung vonLarus ridibundus undHaematopus ostralegus. Regelmäßige Wintervorkommen vonMarmaronetta angustirostris sind erwähnenswert.Es wird mit einigen bisher unbekannten Brutplätzen von Laro-Limicolen bekanntgemacht, von denen eine Kolonie vonSterna albifrons mit 300–400 Paaren besonders vermerkt sei. Für weitere Arten können Bestandsangaben gemacht werden.Dieses einzige, bedeutende Brut- und Rastgebiet zwischen Camargue und Coto Doñana ist in höchster Gefahr, durch intensivere landwirtschaftliche Nutzung und touristische Erschließung vernichtet zu werden.

---

Resumen Datos ornitologicos sobre el Delta del Ebro. — Sin contar con charcas y marismas, el Delta del Ebro es una franja costera aun no explotada por la agricultura. Gracias a esto una numerosa variedad de aves ha podido mantenerse aprovechando las todavia persistentes condiciones orginarias del medio ambiente. Sobre estas aves se han venido acumulando en los ultimos años un buen acopio de observaciones.Se pudo constatar como nidificantes por primera vez en España o costas mediterranes a las siguientes especies:Larus ridibundus, Sterna dougalli, St. sandvicensis, Haematopus ostralegus, Limosa limosa, Asio flammeus, Acrocephalus palustris. Como lugar de invernada o refugio durante el paso el Delta del Ebro tiene un especial interes, por ejemplo paraEgretta garzetta yPhoenicopterus ruber. Se establecen algunas relaciones con la Camarga principalmente en cuanto a la expansión deLarus ridibundus yHaematopus ostralegus. Se mencionan invernadas regulares deMarmaronetta angustirostris. Se señalan algunos nuevos lugares de cria para Laro-Limicolas, merece destacarse el hallazgo de una colonia deSterna albifrons compuesta por unos 300–400 pares. Para otras especies se dan datos numerieos estimativos.El Delta del Ebro es un lugar unico y de gran importancia, situado entre la Camarga y el Coto de Doñana, que está hoy en peligro de desaparición debido a la colonización intensiva de la agricultura y a la creciente afluencia turistica.

     

Dose-response function for Painter's SCE-model

Summary The replication model for sister chromatid exchange (SCE), when introduced in 1980 by Painter, was claimed to be consistent with the one hit property of SCE. However, the argument offered in favour of the one hit property was based on a defective dose-response function, as shown in this paper, since dose as the independent parameter of any dose-response function was not included in the considerations. This missing part of the model's dose-response function is added and, by using Bessel functions, a formula for the complete dose-response function is presented. A re-examination of the newly derived function shows that, in the model, linearity holds only under certain restricted circumstances.     

Expansion of repetitive DNA into cytogenetically visible elements.

Two cases of amplified repetitive elements accidentally identified in cancer samples are reported. In both cases, repeated DNA that is normally not visible by traditional chromosome banding had increased in amount to become cytogenetically visible. In one case, an addition to the short arm of chromosome 1 was originally diagnosed. However, upon molecular analysis the diagnosis could be corrected to an amplification of the D1Z2 repeat. In the second case, a strongly DAPI-positive band was visible at the top of the short arm of chromosome 22, and the original diagnosis was add(22). Staining for telomeric repeats revealed their presence inside the DAPI-positive element, thus confirming that the element in question was truly added to the end of the chromosome. Curiously, no telomeric repeats could be detected distal to the DAPI-positive element. The identity of the DAPI-positive element could not be established, as it was not stained by any of the specific probes applied, nor in a scanning hybridization with labeled Cot-1 DNA. It thus seems to represent an expansion from some lowly repetitive AT-rich DNA translocated to the tip of chromosome 22.     

Treatment of the Obstructive Sleep Apnea Syndrome

The obstructive sleep apnea syndrome is a disorder of sleep and breathing that is being recognized with increasing frequency. The pathophysiologic consequences range from mild sleepiness to life-threatening cardiovascular and respiratory decompensation. The primary forms of treatment are directed at modifying the upper airway with either an operation or continuous positive airway pressure. Aside from tracheostomy, which is virtually always successful, other forms of treatment have met with varying results. Ancillary therapy, including oxygen, weight loss and drugs, is often helpful but seldom curative. Follow-up sleep studies are necessary to evaluate the effectiveness of treatment. Selecting therapy for a patient with obstructive sleep apnea requires a comprehensive evaluation including polysomnography, special examinations of the upper airway and assessing the cardiopulmonary status. Therapy is based on the severity of disease and must be tailored to each patient.     

Highly active and thermostable amylases and pullulanases from various anaerobic thermophiles

Summary High concentrations of amylases and pullulanases were formed by continuous cultivation of Thermoanaerobacter finnii, Thermobacteroides acetoethylicus, Thermoanaerobacter ethanolicus and Clostridium thermosaccharolyticum in chemostats under starch limitation. 70% to 98% of these enzymes were transported and released into the culture fluid. These extracellular enzymes were extremely thermostable under aerobic conditions and in the absence of substrate and metal ions. The amylases and pullulanases from the first three organisms had an optimal temperature of 90°C. The enzymes from C. thermosaccharolyticum were most active at 75°C. The pH optima of the amylolytic enzymes from the microorganisms investigated ranged between 5 and 6. The addition of calcium ions in vitro significantly enhanced pullulanase activity from T. finnii and C. thermosaccharolyticum. The influence of other metal ions and cyclodextrins on the activities of the amylolytic enzymes is also described.     

Variability of the turgor pressure of individual cells of the gram-negative heterotroph Ancylobacter aquaticus.

Cells of Ancylobacter aquaticus were observed under phase microscopy in a chamber to which a measured pressure could be applied. The initial collapse pressure (Ca), i.e., the lowest pressure needed to collapse the most pressure-sensitive gas vesicles, was measured for 69 cells. The cells were taken from cultures in low-density balanced exponential growth, and the experiments were performed quickly so that the bacteria were in a uniform physiological state at the time of measurement. The turgor pressure, Pt, is the difference between the pressure, C, that would cause collapse of vesicles when removed from the cell and Ca. In this paper we focus on the variability of Pt from cell to cell. Part of the observed variability of Ca was due to the variability of the collapse pressure of individual vesicles (standard deviation [SD] = 90 kPa), but because there were about 100 vesicles per cell and because a change in refracted light after the fifth vesicle (approximately) collapsed probably could be detected by the human eye, the pressure would only have an SD of 18.6 kPa due to this type of sampling error. The observed SD of Pt was 42 kPa, indicating that turgor pressure did vary considerably from cell to cell. However, the turgor pressure was independent of cell size. Statistical analysis showed that Pt would decrease 6.9 kPa over a cell cycle, but with too large an SD (19.9 kPa) to be significant. This implies that the observed change in Pt over the cell cycle is not statistically significant.     

Expression of antibody cDNA in murine myeloma cells: possible involvement of additional regulatory elements in transcription of immunoglobulin genes

Expression vectors for cDNA of the κ and λ1 chains of a monoclonal antibody directed against creatine kinase were introduced into murine myeloma cells. κ and γ1 cDNA were either under the control of the SV40 early promoter or of the cognate promoters and enhancers of the light- and heavy-chain genes. Secretion of immuno-reactive κ and γ1 chains into the culture medium was demonstrated with the SV40 promoter as well as with the cognate promoters. Expression of y 1 cDNA with the SV40 early promoter was about twice as high as with the heavy-chain promoter and enhancer. Expression of κ cDNA under the control of the S V40 early promoter was about 17 times higher than with the light-chain promoter and enhancer. These expression levels were compared to those of a genomic immunoglobulin (Ig) κ determinant, including introns. Such an entire κ gene led to expression of the light chain at levels double those with the κ cDNA construction using the SV40 promoter and about 35 times as high when using κ cDNA and the cognate promoter and enhancer. This result might indicate that, besides the cognate promoter and enhancer elements, other intragenic elements are involved in the regulation of Ig expression. However, the SV40 early promoter seems to be able to compensate for the absence of these postulated regulatory elements probably located in the introns.     

Responses of wild plants to nitrate availability

Summary Two annual species of Bromus, an invader (B. hordeaceus, ex B. mollis) and a non-invader (B. intermedius), were grown for 28 days in growth chambers, at 5 and 100 M NO ₃ ^- in flowing nutrient solution. No differences between the two species were observed at either NO ₃ ^- level, in terms of relative growth rate (RGR) or its components, dry matter partitioning, specific NO ₃ ^- absorption rate, nitrogen concentration, and other characteristics of NO ₃ ^- uptake and photosynthesis. The effects of decreasing NO ₃ ^- concentration in the solution were mainly to decrease the NO ₃ ^- concentration in the plants through decreased absorption rate, and to decrease the leaf area ratio through increased specific leaf mass and decreased leaf mass ratio. Organic nitrogen concentration varied little between the two treatments, which may be the reason why photosynthetic rates were not altered. Consequently, RGR was only slightly decreased in the 5-M treatment compared to the 100-M treatment. This is in contrast with other species, where growth is reduced at much higher NO ₃ ^- concentrations. These discrepancies may be related to differences in RGR, since a log-linear relationship was found between RGR and the NO ₃ ^- concentration at which growth is first reduced. In addition, a strong linear relationship was found between the RGR of these species and their maximum absorption rate for nitrate, suggesting that the growth of species with low maximum RGR may be partly regulated by nutrient uptake.