Experimentell- ökologische Untersuchungen über die limitierenden Faktoren des mikrobiellen Ölabbaues im marinen Milieu

Zusammenfassung 1. Die Vermehrungsrate ölabbauender Bakterien und die Intensität des Ölabbaus wird im Seewasser durch Zugabe anorganischer Stickstoff- und Phosphorsalze wesentlich gefördert. In unzureichenden Mengen stellen diese Salze einen sehr wirksamen limitierenden Faktor dar.2. In den daraufhin untersuchten Sedimenten findet keine Förderung des Ölabbaus durch Zufügung anorganischer Stickstoff- und Phosphorsalze statt, obwohl beträchtlich höhere Mengen dieser Salze als im Seewasser vorhanden waren. Vermutlich findet hier eine Begrenzung des Abbaues durch Sauerstoffmangel statt; jedenfalls deutet die Bildung von schwefelwasserstoffhaltigen Zonen auf eine derartige Möglichkeit hin.3. Die Zugabe von Anreicherungskulturen führte nicht generell zu einem verstärkten Ölabbau.4. Gleichzeitig vorhandene, leicht abbaubare organische Substanzen hemmen den Ölabbau sehr stark.5. Niedrige Wassertemperaturen haben einen stark verzögernden Einfluß auf den Ölabbau.6. In Heizöl-Wasser-Gemischen besiedeln die Bakterien fast ausschließlich die Grenzflächen Öl-Wasser.7. Bakterien sind in der Lage, in Petroleum-Wasser-Gemischen das Petroleum weitgehend zu emulgieren und dadurch die Abbauvorgänge zu beschleunigen.

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Experimental-ecological investigations regarding the limiting factors of microbial oil degradation in the marine environment

This contribution deals with model experiments of bacterial oil degradation. It considers oils which are likely to pollute the marine environment. The amounts of different oils resisting bacterial degradation were determined quantitatively. Numbers of oil decomposing bacteria were counted using a MPN (most-probable-number) technique with mineral oils as the only carbon source. The influence of the following factors was determined: inorganic nitrogen- and phosphate salts, enrichment cultures, easily decomposable organic substances (other than oil), and temperature. In most experiments freshly sampled seawater with its natural content of marine bacteria was used. The special distribution of oil decomposing bacteria in oil-water mixtures was investigated. The possible influence of these factors on the degradation of mineral oils in the sea is discussed.

     

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Incidence of peptic ulcer disease in Gothenburg, 1985.

OBJECTIVE--To determine the incidence and age distribution of peptic ulcer disease in adults in Gothenburg. DESIGN--Retrospective study of patients with symptoms over one year. SETTING--All gastroenterology and x ray departments. PATIENTS--Any patient found to have an active ulcer crater during 1985. MAIN OUTCOME MEASURES--Sex, age, past history of gastrointestinal ulcers, and smoking habit. RESULTS--In 1985, 1402 peptic ulcers were diagnosed in 1137 adults. Over half (403; 54%) of the ulcers in men and 393 (60%) ulcers in women were in patients aged over 60. All types of ulcer showed increasing incidence with age. The sex ratio of patients aged 40-50 with peptic ulcers was 1:1. Nearly half (109; 48%) of ulcers diagnosed for the first time in men and 129 (57%) of such ulcers in women were in patients aged over 60. Elderly men and women were also more likely to develop haemorrhage. CONCLUSIONS--In Gothenburg there is a surprisingly high incidence of peptic ulcer disease, which increases considerably with age, possibly explained by the availability of modern diagnostic techniques as 1121 (80%) ulcers had been diagnosed by gastroscopy. Compared with earlier studies there was no difference in the incidence between men and women aged 40-50.     

Extreme differences in charge changes during protein evolution

Summary The maintenance of a proper distribution of charged amino acid residues might be expected to be an important factor in protein evolution. We therefore compared the inferred changes in charge during the evolution of 43 protein families with the changes expected on the basis of random base substitutions. It was found that certain proteins, like the eye lens crystallins and most histones, display an extreme avoidance of changes in charge. Other proteins, like phospholipase A2 and ferredoxin, apparently have sustained more charged replacements than expected, suggesting a positive selection for changes in charge. Depending on function and structure of a protein, charged residues apparently can be important targets for selective forces in protein evolution. It appears that actual biased codon usage tends to decrease the proportion of charged amino acid replacements. The influence of nonrandomness of mutations is more equivocal. Genes that use the mitochondrial instead of the universal code lower the probability that charge changes will occur in the encoded proteins.     

Chromosomal evolution withinPiperaceae

Chromosome numbers for 26 different species of the generaPiper, Peperomia andPothomorphe (Piperaceae) are reported. The basic chromosome numbers are 2n = 26, x = 13 (Piper, Pothomorphe) and 2n = 22, x = 11 (Peperomia), polyploid series are characteristic forPiper andPeperomia. Piper has the smallest chromosomes and prochromosomal interphase nuclei,Peperomia the largest ones and mostly reticulate to euchromatic nuclei.Pothomorphe is intermediate in both characters. The karyomorphological differences betweenPothomorphe andPiper underline their generic separation. Interspecific size variation of chromosomes occurs inPiper andPeperomia. Infraspecific polyploidy was observed inPiper betle. C-banding reveals different patterns of heterochromatin (hc) distribution between the genera investigated. The genome evolution is discussed.     

The perennial taxa ofCrucianella (Rubiaceae) in SW. Asia and their eco-geographical differentiation

The perennial taxa ofCrucianella in Asia form a coherent group, apparently diploid (x = 11) and outbreeding throughout, and should be placed into sect.Roseae. This Irano-Turanian group has its centre of diversity in the mountain systems south of the Caspian Sea and reaches with outposts NE. and E. Anatolia, NE. Iraq, S. Iran and C. Asia. Four species and 13 subspecies (within the polymorphicC. gilanica) are recognized, described (partly as new), and illustrated (Figs. 1–6). Conspectus, keys and distribution maps (Figs. 7 and 8) as well as plesio- and apomorphic character states and data on size of areas are provided (Table 1). There is an obvious correlation between more plesiomorphic taxa with smaller areas in the distribution centre of the group, and more apomorphic taxa with larger areas towards its periphery (Fig. 9). These findings are linked to a working hypothesis on the evolution of the group.Dedicated to Prof. DrLothar Geitler on the occasion of his 90th birthday.     

Tumor necrosis factor signal transduction. Tissue-specific serine phosphorylation of a 26-kDa cytosolic protein

Binding of tumor necrosis factor-alpha (TNF-alpha) to its receptor on U937 cells results in rapid and TNF dose-dependent phosphorylation of a cytosolic protein with an apparent molecular mass of 26,000 kDa (p26) and an isoelectric point of 5.6. Half-maximal phosphorylation of p26 was achieved at concentrations of 1.8 ng/ml and was detectable within 20 s of TNF-alpha treatment. p26 is phosphorylated exclusively at serine residues. p26 phosphorylation occurs at 37 degrees C as well as at 14 degrees C, indicating that internalization of the TNF receptor is not required for serine kinase activation. Dephosphorylation of p26 starts 10 min after TNF-induced phosphorylation, suggesting a possible regulatory function of this cytosolic protein within the post-TNF receptor signaling system. p26 is also phosphorylated upon treatment with lymphotoxin. In contrast, both interferon-gamma and lipopolysaccharide fail to induce p26 phosphorylation. Whereas phosphorylated p26 was detected in the TNF-sensitive breast cancer cell line CRL1500, other TNF-responsive tumor cell lines investigated lacked enhanced phosphorylation of p26 in response to TNF, indicating that the 26-kDa phosphoprotein (pp26) may be a cell type-specific second messenger molecule involved in TNF signal transduction in some, but not all, target cells. p26 is also phosphorylated in a subclone of U937 (U937.C27) that responds to TNF-alpha with differentiation, yet is resistant to TNF-alpha-mediated growth inhibition. In contrast, p26 is not phosphorylated in another U937 derivative (U937.G3) that is resistant to both TNF-alpha-induced growth arrest and differentiation, suggesting that pp26 may play a role in the TNF signaling pathway linked to differentiation processes rather than to growth control.     

Inversion of gravitropism by symmetric blue light on the clinostat

Gravitropic stimulation of maize (Zea mays L.) seedlings resulted in a continuous curvature of the coleoptiles in a direction opposing the vector of gravity when the seedlings were rotated on a horizontal clinostat. The orientation of this response, however, was reversed when the gravitropic stimulation was preceeded by symmetric preirradiation with blue light (12.7 mol photons·m^–2). The fluence-response curve of this blue light exhibited a lower threshold at 0.5 mol·m^–2, and could be separated into two parts: fluences exceeding 5 mol·m^–2 reversed the direction of the gravitropic response, whereas for a range between the threshold and 4 mol·m^–2 a split population was obtained. In all cases a very strong curvature resulted either in the direction of gravity or in the opposite orientation. A minor fraction of seedlings, however, curved towards the caryopsis. Furthermore, the capacity of blue light to reverse the direction of the gravitropic response disappeared with the duration of gravitropic stimulation and it depended on the delay time between both stimulations. Thistonic blue-light influence appears to be transient, which is in contrast to the stability observed fortropistic blue-light effects.This work was supported by the Deutsche Forschungsgemeinschaft.     

A cyclic AMP response element mediates repression of tyrosine aminotransferase gene transcription by the tissue-specific extinguisher locus Tse-1

Tyrosine aminotransferase (TAT) gene expression is liver specific and inducible by glucocorticoids and via the cAMP signaling pathway. In fibroblasts and other nonliver cells the gene is subject to negative control by the trans-dominant tissue-specific extinguisher locus Tse-1. We identified a hepatocyte-specific enhancer that is repressed by Tse-1. Two distinct sequence motifs are absolutely essential for function of this enhancer: a cAMP response element (CRE), which is the target for repression by Tse-1, and a hepatocyte-specific element. The specificity of the enhancer is generated by the combination of these two essential elements, which are fully interdependent. In vivo footprinting indicates that Tse-1 acts by affecting protein binding at the CRE. A direct antagonism between Tse-1 and the cAMP signaling pathway suggests that Tse-1 plays a role in control of developmental activation of the TAT gene.