Radio-gaschromatographische Untersuchungen über die Herkunft der Glykolsäure in photosynthetisch aktiven Chlorella-Suspensionen

Chlorella-Massenkulturen, die bei 27 C im Algenanzuchtthermostaten mit automatischer Verdünnungseinheit mit 1% CO₂ und 21% O₂ im Dauerlicht (310 Mikroeinstein · m^?2 · s^?1) heranwuchsen, sowie teilsynchronisierte Kulturen sind abzentrifugiert, in frischer Nährlösung wieder aufgenommen und schließlich in der Versuchsküvette zehn Minuten mit 101 ppm ¹⁴CO₂ oder 543 ppm ¹⁴CO₂ und jeweils 80% O₂ equilibriert und dann im offenen Gasstrom belichtet worden. Im Dunkeln war in diesen Algen kein Glykolat nachzuweisen. Nach einer kurzen Anlaufphase erreichte die Glykolsäure-Exkretion im Starklicht (1400 Mikroeinstein · m^?2 · s^?1) schnell große Werte. Bei hohen Atmungsraten, die keine (101 ppm CO₂) oder nur eine geringe (543 ppm CO₂) Netto-Photosynthese zuließen, sind im Licht bis zu 37% des assimilierten ¹⁴C im Glykolat wiedergefunden worden. Die spezifische Radioaktivität der Glykolsäure hing von der Kohlendioxid-Konzentration während der ¹⁴CO₂-Fixierung als auch von der Anzucht und Vorbehandlung der Algen ab, überstieg jedoch auch nach 20- bis 30minütiger Photosynthese nicht 28% der spezifischen Radioaktivität des assimilierten ¹⁴CO₂. Da die Kinetik der spezifischen Radioaktivität der 3-PGS außerdem anders verlief als die der Glykolsäure, wird die Glykolsäure in Chlorella vulgaris nicht nur aus soeben assimilierten Intermediaten des Photosynthese-Zyklus, sondern vermutlich auch aus älteren Reservestoffen gebildet. Der Deutschen Forschungsgemeinschaft danken wir für eine großzügige Sachbeihilfe. Fräulein Lieselotte Schäfer sei für ihre bewährte technische Assistenz gedankt.     

Europe‐wide biogeographical patterns in the diet of an ecologically and epidemiologically important mesopredator,the red fox Vulpes vulpes: a quantitative review

相似文献   

Intracellular bacteriolysis triggers a massive apoptotic cell death in Shigella-infected epithelial cells

Infected epithelial cells, which act as a first barrier against pathogens, seldom undergo apoptosis. Rather, infected epithelial cells undergo a slow cell death that displays hallmarks of necrosis. Here, we demonstrate that rapid intracellular lysis of Shigella flexneri, provoked by either the use of a diaminopimelic acid auxotroph mutant or treatment of infected cells with antibiotics of the beta-lactam family, resulted in a massive and rapid induction of apoptotic cell death. This intracellular bacteriolysis-mediated apoptotic death (IBAD) was characterized by the specific involvement of the mitochondrial-dependent cytochrome c/Apaf-1 axis that resulted in the activation of caspases-3, -6 and -9. Importantly, Bcl-2 family members and the NF-kappaB pathway seemed to be critical modulators of IBAD. Finally, we identified that IBAD was also triggered by Salmonella enterica serovar Typhimurium but not by the Gram-positive bacteria, Listeria monocytogenes. Together, our results demonstrate that, contrary to previous findings, epithelial cells are intrinsically able to mount an efficient apoptotic cell death response following infection. Indeed, apoptosis in normal circumstances is masked by powerful anti-apoptotic mechanisms, which are overcome in IBAD. Our results also uncover an unexpected consequence of the treatment of infected cells with certain classes of antibiotics.     

Antiproliferative effects on human tumor cells and rat aortic smooth muscular cells of 2,3-heteroarylmaleimides and heterofused imides

A series of 2,3-heteroarylmaleimides 9 and polyheterocondensed imides 12 were prepared in good yields and short reaction time using a very efficient procedure consisting in the condensation of the corresponding anhydrides and N,N-diethylethylenediamine and microwave heating. The antiproliferative activity of the novel molecules was tested against human tumor cells (NCI-H460 lung carcinoma) and rat aortic smooth muscle cells (SMCs). The IC50 values for the novel molecules ranged from 0.08 to 13.9 microM in SMCs, and from 0.84 to 9 microM in the tumor cell line. The activity profile for compounds 9 and 12 is comparable to that obtained for amonafide in NCI-H460, except for fused imides 12b,i which proved to be about 10-fold more potent. Whereas, in rat SMCs, only the compound 12b was shown to be 10-fold more potent than amonafide. Instead 12c is equipotent to amonafide. These results suggest that the extended pi-system and the kind of heteroatom are essential in the binding with the molecular target.     

Environmentally Dependent Morphological Variability in Seven Apomictic Microspecies from Alchemilla L. (Rosaceae)

Apomictic microspecies, for example those of the genus Alchemilla, are often difficult to distinguish. Still, their differences are thought to be persistent due to apomixis. Apomicts are argued to have general-purpose genotypes. The present study aims to assess the variation of morphological characters of Alchemilla depending on environmental conditions both in nature and experimentally; to evaluate the efficacy of characters for identifying the different microspecies; to assess the similarity of different microspecies; and to determine if Alchemilla microspecies have general-purpose genotypes that are not dependent on environmental conditions. The variability of selected characters in seven microspecies of Alchemilla was studied in nature and five microspecies were grown in a common garden experiment. The growing conditions of the latter were subjected to various manipulations (fertilization, shading and irrigation). Typical natural habitats of Alchemilla exhibited only small differences. Environmental conditions therefore had little effect on morphological characters. Neither cultivation in the common garden nor manipulation of conditions therein had a significant impact on the discrimination of microspecies. However, the metric characters were larger in the garden relative to those observed in nature, particularly under fertilization. Fertilization affected most characters, whereas shading and irrigation did not. The most effective characters for discriminating between microspecies were the ratios of the metric characters. Two species pairs: A. vulgaris and A. micans, as well as A. glaucescens and A. hirsuticaulis were morphologically close; however, the species within these pairs could still be distinguished. The morphological characters of Alchemilla microspecies were only slightly dependent on the environmental conditions.     

Ovarian Cancer Cell Heparan Sulfate 6-O-Sulfotransferases Regulate an Angiogenic Program Induced by Heparin-binding Epidermal Growth Factor (EGF)-like Growth Factor/EGF Receptor Signaling

Heparan sulfate (HS) is a component of cell surface and extracellular matrix proteoglycans that regulates numerous signaling pathways by binding and activating multiple growth factors and chemokines. The amount and pattern of HS sulfation are key determinants for the assembly of the trimolecular, HS-growth factor-receptor, signaling complex. Here we demonstrate that HS 6-O-sulfotransferases 1 and 2 (HS6ST-1 and HS6ST-2), which perform sulfation at 6-O position in glucosamine in HS, impact ovarian cancer angiogenesis through the HS-dependent HB-EGF/EGFR axis that subsequently modulates the expression of multiple angiogenic cytokines. Down-regulation of HS6ST-1 or HS6ST-2 in human ovarian cancer cell lines results in 30–50% reduction in glucosamine 6-O-sulfate levels in HS, impairing HB-EGF-dependent EGFR signaling and diminishing FGF2, IL-6, and IL-8 mRNA and protein levels in cancer cells. These cancer cell-related changes reduce endothelial cell signaling and tubule formation in vitro. In vivo, the development of subcutaneous tumor nodules with reduced 6-O-sulfation is significantly delayed at the initial stages of tumor establishment with further reduction in angiogenesis occurring throughout tumor growth. Our results show that in addition to the critical role that 6-O-sulfate moieties play in angiogenic cytokine activation, HS 6-O-sulfation level, determined by the expression of HS6ST isoforms in ovarian cancer cells, is a major regulator of angiogenic program in ovarian cancer cells impacting HB-EGF signaling and subsequent expression of angiogenic cytokines by cancer cells.     

Zur Kenntnis des Lichtfeldes der Pflanze und der Blattfarbstoffe

Ohne ZusammenfassungMit 15 Textabbildungen.     

Trends in the Attack Rates,Incidence, and Mortality of Stroke during 1986–2012: Data of Kaunas (Lithuania) Stroke Registry

BackgroundThere is a lack of reliable epidemiological data on longitudinal trends in stroke attack rates, incidence, and mortality in the countries of the Baltic region.AimsThe aim of the present study was to explore the longitudinal trends of stroke in middle-aged urban population of Lithuania during the period of 1986 through 2012.MethodsAll stroke events in the studied population were ascertained and validated according to the standardized criteria outlined by the WHO MONICA Project. The study included all patients in Kaunas (Lithuania) city aged 25 to 64 years who experienced a stroke between 1986 and 2012. Estimates of time-trends of the annual percentage change in stroke attack rates, incidence of stroke, and mortality from this condition were made by applying the Joinpoint regression analysis.ResultsDuring the study period, 9,992 stroke events were registered. The overall proportion of recurrent events was 25.7%. Overall, 18.9% of the events (20.0% in men, and 17.4% in women) were fatal within 28 days. During the period of 1986 to 2012, a flat trend in the incidence of stroke was observed among both male and female middle-aged inhabitants of Kaunas city, while attack rates were increasing due to the increase in recurrent strokes. Both mortality and 28-day case fatality of stroke declined significantly over the study period in both sexes.ConclusionsAn increase both in the incidence and recurrence of stroke among middle-aged men residing in Kaunas city and in the recurrence of stroke among women denotes the inefficiency of measures applied both for primary and secondary prevention of stroke in Lithuania. The revision of current prevention strategies and the introduction of new ones are of paramount importance in order to fight the epidemic of stroke.