The taphonomic fate of isorenieratene in Lower Jurassic shales—controlled by iron?

Fossil derivatives of isorenieratene, an accessory pigment in brown‐colored green sulfur bacteria, are often used as tracers for photic zone anoxia through Earth's history, but their diagenetic behavior is still incompletely understood. Here, we assess the preservation of isorenieratene derivatives in organic‐rich shales (1.5–8.4 wt.% TOC) from two Lower Jurassic anoxic systems (Bächental oil shale, Tyrol, Austria; Posidonia Shale, Baden‐Württemberg, Germany). Bitumens and kerogens were investigated using catalytic hydropyrolysis (HyPy), closed‐system hydrous pyrolysis (in gold capsules), gas chromatography–mass spectrometry (GC–MS) and gas chromatography combustion isotope ratio‐mass spectrometry (GC‐C‐IRMS). Petrography and biomarkers indicate a syngenetic relationship between bitumens and kerogens. All bitumens contain abundant isorenieratane, diverse complex aromatized isorenieratene derivatives, and a pseudohomologous series of 2,3,6‐trimethyl aryl isoprenoids. In contrast, HyPy and mild closed‐system hydrous pyrolysis of the kerogens yielded only minor amounts of these compounds. Given the overall low maturity of the organic matter (below oil window), it appears that isorenieratene and its abundant derivatives from the bitumen had not been incorporated into the kerogens. Accordingly, sulfur cross‐linking, the key mechanism for sequestration of functionalized lipids into kerogens in anoxic systems, was not effective in the Jurassic environments studied. We explain this by (i) early cyclization/aromatization and (ii) hydrogenation reactions that have prevented effective sulfurization. In addition, (iii) sulfide was locally removed via anoxygenic photosynthesis and efficiently trapped by the reaction with sedimentary iron, as further indicated by elevated iron contents (4.0–8.7 wt.%) and the presence of abundant pyrite aggregates in the rock matrix. Although the combined processes have hampered the kerogen incorporation of isorenieratene and its derivatives, they may have promoted the long‐term preservation of these biomarkers in the bitumen fraction via early defunctionalization. This particular taphonomy of aromatic carotenoids has to be considered in studies of anoxic iron‐rich environments (e.g., the Proterozoic ocean).     

Ethylene responses in Arabidopsis seedlings include the reduction of curvature values in the root cap

Recently, curvature was described as a new trait useful in the analysis of root apex shape. Treating the root profile as a geometric curve revealed that root apex curvature values are lower in ethylene-insensitive mutants (Cervantes E, Tocino A. Geometric analysis of Arabidopsis root apex reveals a new aspect of the ethylene signal transduction pathway in development. J Plant Physiol 2005;162:1038-45). This fact suggests that curvature is regulated by ethylene. In this work, we have determined the curvature values in embryonic roots of wild-type Columbia as well as in ethylene signal-transduction mutants, and found smaller values in embryos of the mutants. We also report on the evolution of root curvature during early development after seed germination. The line Lt16b that expresses GFP in the cell wall has allowed us to investigate the evolution of curvature values in three successive cell layers of seedling roots by confocal microscopy. Treatment of seedlings with norbornadiene resulted in lower curvature values. Our results show details illustrating the effect of ethylene in root curvature.     

Screening of marine actinobacteria for amylase enzymes inhibitors

Amylase inhibitor producing actinobacteria were isolated and characterized from terrestrial environment and there is no much report found from marine environment, hence in the present study, 17 strains isolated from the rhizosphere sediments of mangroves were tested for their amylase inhibition ability. Seawater requirement test for the growth of actinobacteria found that the strains SSR-3, SSR-12 and SSR-16 requires at least 50% and SSR-6 requires at least 25% seawater for their growth. The inhibition activity of both prokaryotic and eukaryotic amylase was tested by using Bacillus subtilis and Aspergillus niger. The maximum amylase activity (40mm) produced by the A. niger was taken as positive control, when the test actinobacteria strains grown in the medium they inhibited amylase activity and was evidenced by the reduction in inhibition zone (14–37 mm) similarly the amylase produced by the Bacillus subtilis was also recorded maximum (35 mm) amylase activity and was taken as positive control, and the test atinobacterial strains reduced enzyme action(12–33 mm) it varied levals. This indicates that the actinobacteria strains were controlled amylase enzyme activity in both the cases. The strain SSR-10 was highly effective and SSR-8 was less effective in inhibiting eukaryotic amylase produced by A. niger. The strain SSR-2 was effective and SSR-6 showed very less effect in inhibiting the prokaryotic amylase produced by the B subtilis.     

Biodiversitätsforschung – wohin geht die Reise?

Biodiversity and biodiversity politics Extrapolations for a range of indicators suggest that based on current trends, pressures on biodiversity will continue to increase (Global Biodiversity Outlook 4, 2014). Since services of nature, like fertile soil, clear water and clean air are achieved by consortia of organisms rather than by individual species, they are already endangered. This holds, in spite of the fact, that only 10% of the earth's organisms are known to science and that therefore the loss caused by global change cannot be reliably quantified. Today, science develops new methods for recording consortia of coexisting organisms in a habitat. With the Convention on Biological Diversity, biodiversity has become a matter of politics which is welcome with respect to species and habitat conservation, but the concern of biopiracy creates bureaucratic hurdles hindering research. The most recent achievement is IPBES (Intergovernmental Platform on Biodiversity and Ecosystem Services, Bonn), which strives to bring more science into biodiversity politics.     

Personalisierte Medizin – Vision oder Fiktion? Beispiel: Altersdiabetes

Typical civilization diseases, such as type II diabetes, are common, complex in the underlying pathogenic mechanisms, heterogenous in the phenotype and multifactorial due to a wide variety of possible combinations of disease susceptibility or protective genes in different relevant tissues and negative or positive environmental factors. This is in sharp contrast to classical inherited diseases, such as Chorea Huntington, which are often caused by complete loss‐ or gain‐of‐function mutations in a single gene. The causative polymorphisms of susceptibility genes, however, are characterized by relative subtle alterations in the function of the corresponding gene product, which per se do not support the pathogenesis, by high frequency, high expenditure for their identification and rather low predictive value. Consequently, the reliable and early diagnosis of civilization diseases depends on the individual determination of all (or as many as possible) polymorphisms of each susceptibility gene together with the corresponding gene products and the metabolites emerging thereof.     

Wie wachsen Tropenbäume? Jahrringe als Ausdruck von Klimabedingungen und Lebensform

Growth of tropical trees is largely depending on the seasonality of the local climate. In many trees growing in areas with a distinct dry season, cambial activity ceases resulting in the formation of annual rings. In very humid mountain rainforests, trees stop to grow already after short rainless periods. By a combination of increment measurements and wood anatomical analyses, the climatic control of wood formation can be assessed. Intra‐annual wood density variations and content of various stable isotopes enable the climatological interpretation of the “wood signals”.     

耐高温α－淀粉酶在生产超高麦芽糖浆中应用的研究

本文着重研究了耐高温α－淀粉酶与ＢＦ—７６５８α－淀粉酶（即普通中温淀粉酶）在超高麦芽糖浆生产中的区别。使用耐高温α－淀粉酶可使淀粉液化更完全,并且可降低酶的用量,同时生产的超高麦芽糖浆中麦芽糖含量大大提高,具有一定的推广、使用价值。