Experimental Measurements and Mathematical Modeling of Cytosolic Ca2+ Signatures upon Elicitation by Penta-N-acetylchitopentaose Oligosaccharides in Nicotiana tabacum Cell Cultures

Mrozek K, Niehaus K, Lutter P. Experimental Measurements and Mathematical Modeling of Cytosolic Ca2+ Signatures upon Elicitation by Penta-N-acetylchitopentaose Oligosaccharides in Nicotiana tabacum Cell Cultures. Plants. 2013;2(4):750-788

TICAL - a web-tool for multivariate image clustering and data topology preserving visualization

In life science research bioimaging is often used to study two kinds of features in a sample simultaneously: morphology and co-location of molecular components. While bioimaging technology is rapidly proposing and improving new multidimensional imaging platforms, bioimage informatics has to keep pace in order to develop algorithmic approaches to support biology experts in the complex task of data analysis. One particular problem is the availability and applicability of sophisticated image analysis algorithms via the web so different users can apply the same algorithms to their data (sometimes even to the same data to get the same results) and independently from her/his whereabouts and from the technical features of her/his computer. In this paper we describe TICAL, a visual data mining approach to multivariate microscopy analysis which can be applied fully through the web.We describe the algorithmic approach, the software concept and present results obtained for different example images

Optimal Detection for Diffusion-Based Molecular Timing Channels

This work studies optimal detection for communication over diffusion-based molecular timing (DBMT) channels. The transmitter simultaneously releases multiple information particles, where the information is encoded in the time of release. The receiver decodes the transmitted information based on the random time of arrival of the information particles, which is modeled as an additive noise channel. For a DBMT channel without flow, this noise follows the L\'evy distribution. Under this channel model, the maximum-likelihood (ML) detector is derived and shown to have high computational complexity. It is also shown that under ML detection, releasing multiple particles improves performance, while for any additive channel with $\alpha$-stable noise where $\alpha<1$ (such as the DBMT channel), under linear processing at the receiver, releasing multiple particles degrades performance relative to releasing a single particle. Hence, a new low-complexity detector, which is based on the first arrival (FA) among all the transmitted particles, is proposed. It is shown that for a small number of released particles, the performance of the FA detector is very close to that of the ML detector. On the other hand, error exponent analysis shows that the performance of the two detectors differ when the number of released particles is large.Comment: 16 pages, 9 figures. Submitted for publicatio

A Web2.0 Strategy for the Collaborative Analysis of Complex Bioimages

Loyek C, Kölling J, Langenkämper D, Niehaus K, Nattkemper TW. A Web2.0 Strategy for the Collaborative Analysis of Complex Bioimages. In: Gama J, Bradley E, Hollmén J, eds. Advances in Intelligent Data Analysis X: 10th International Symposium, IDA 2011, Porto, Portugal, October 29-31, 2011. Proceedings. Lecture Notes in Computer Science. Vol 7014. Berlin, Heidelberg: Springer; 2011: 258-269

Proteomic and metabolomic analysis of the carotenogenic yeast Xanthophyllomyces dendrorhous using different carbon sources

Martinez-Moya P, Niehaus K, Alcaino J, Baeza M, Cifuentes V. Proteomic and metabolomic analysis of the carotenogenic yeast Xanthophyllomyces dendrorhous using different carbon sources. BMC Genomics. 2015;16(1): 289.Background: Astaxanthin is a potent antioxidant with increasing biotechnological interest. In Xanthophyllomyces dendrorhous, a natural source of this pigment, carotenogenesis is a complex process regulated through several mechanisms, including the carbon source. X. dendrorhous produces more astaxanthin when grown on a non-fermentable carbon source, while decreased astaxanthin production is observed in the presence of high glucose concentrations. In the present study, we used a comparative proteomic and metabolomic analysis to characterize the yeast response when cultured in minimal medium supplemented with glucose (fermentable) or succinate (non-fermentable). Results: A total of 329 proteins were identified from the proteomic profiles, and most of these proteins were associated with carotenogenesis, lipid and carbohydrate metabolism, and redox and stress responses. The metabolite profiles revealed 92 metabolites primarily associated with glycolysis, the tricarboxylic acid cycle, amino acids, organic acids, sugars and phosphates. We determined the abundance of proteins and metabolites of the central pathways of yeast metabolism and examined the influence of these molecules on carotenogenesis. Similar to previous proteomic-stress response studies, we observed modulation of abundance from several redox, stress response, carbohydrate and lipid enzymes. Additionally, the accumulation of trehalose, absence of key ROS response enzymes, an increased abundance of the metabolites of the pentose phosphate pathway and tricarboxylic acid cycle suggested an association between the accumulation of astaxanthin and oxidative stress in the yeast. Moreover, we observed the increased abundance of late carotenogenesis enzymes during astaxanthin accumulation under succinate growth conditions. Conclusions: The use of succinate as a carbon source in X. dendrorhous cultures increases the availability of acetyl-CoA for the astaxanthin production compared with glucose, likely reflecting the positive regulation of metabolic enzymes of the tricarboxylic acid and glyoxylate cycles. The high metabolite level generated in this pathway could increase the cellular respiration rate, producing reactive oxygen species, which induces carotenogenesis

Analysis of outer membrane vesicle associated proteins isolated from the plant pathogenic bacterium Xanthomonas campestris pv. campestris

Sidhu VK, Vorhölter F-J, Niehaus K, Watt SA. Analysis of outer membrane vesicle associated proteins isolated from the plant pathogenic bacterium Xanthomonas campestris pv. campestris. BMC Microbiology. 2008;8(1):87.Background: Outer membrane vesicles (OMVs) are released from the outer membrane of many Gram-negative bacteria. These extracellular compartments are known to transport compounds involved in cell-cell signalling as well as virulence associated proteins, e. g. the cytolysine from enterotoxic E. coli. Results: We have demonstrated that Xanthomonas campestris pv. campestris (Xcc) releases OMVs into the culture supernatant during growth. A proteome study identified 31 different proteins that associate with the OMV fraction of which half are virulence-associated. A comparison with the most abundant outer membrane ( OM) proteins revealed that some proteins are enriched in the OMV fraction. This may be connected to differences in the LPS composition between the OMVs and the OM. Furthermore, a comparison of the OMV proteomes from two different culture media indicated that the culture conditions have an impact on the protein composition. Interestingly, the proteins that are common to both culture conditions are mainly involved in virulence. Conclusion: Outer membrane vesicles released from the OM of Xcc contain membrane- and virulence-associated proteins. Future experiments will prove whether these structures can serve as "vehicles" for the transport of virulence factors into the host membrane

Metabolite profiling of somatic embryos of Cyclamen persicum in comparison to zygotic embryos, endosperm, and testa

Winkelmann T, Ratjens S, Bartsch M, Rode C, Niehaus K, Bednarz H. Metabolite profiling of somatic embryos of Cyclamen persicum in comparison to zygotic embryos, endosperm, and testa. Frontiers in Plant Science. 2015;6: 597.Somatic embryogenesis has been shown to be an efficient in vitro plant regeneration system for many crops such as the important ornamental plant Cyclamen persicum, for which this regeneration pathway of somatic embryogenesis is of interest for the vegetative propagation of parental lines as well as elite plants. However, somatic embryogenesis is not commercially used in many crops due to several unsolved problems, such as malformations, asynchronous development, deficiencies in maturation and germination of somatic embryos. In contrast, zygotic embryos in seeds develop and germinate without abnormalities in most cases. Instead of time-consuming and labor-intensive experiments involving tests of different in vitro culture conditions and plant growth regulator supplements, we follow a more directed approach. Zygotic embryos served as a reference and were compared to somatic embryos in metabolomic analyses allowing the future optimization of the in vitro system. The aims of this study were to detect differences in the metabolite profiles of torpedo stage somatic and zygotic embryos of C. persicum. Moreover, major metabolites in endosperm and testa were identified and quantified. Two sets of extracts of two to four biological replicates each were analyzed. In total 52 metabolites were identified and quantified in the different tissues. One of the most significant differences between somatic and zygotic embryos was that the proline concentration in the zygotic embryos was about 40 times higher than that found in somatic embryos. Epicatechin, a scavenger for reactive oxygen species, was found in highest abundance in the testa. Sucrose, the most abundant metabolite was detected in significantly higher concentrations in zygotic embryos. Also, a yet unknown trisaccharide, was significantly enriched in zygotic embryos

Methoden für die Unterscheidung von ökologisch und konventionell erzeugten Lebensmitteln

Bioprodukte werden heute immer stärker international und über komplexe Wertschöpfungsketten produziert und gehandelt. Dadurch werden Kontrollen, welche die Authentizität der Bio-Produkte zuverlässig gewähren, immer schwieriger. Höhere Preise für Bioprodukte waren in der Vergangenheit zudem Motivation hinter einzelnen Betrugsfällen in der Biobranche. Aus diesem Grund braucht es weitere Methoden, welche die Kontrollen der Zertifizierungsstellen unterstützen und ergänzen. Außer dem analytischen Nachweis von chemisch-synthetischen Pestizidrückständen, der bereits seit geraumer Zeit in der Praxis etabliert ist, gibt es weitere analytische und ganzheitliche Methoden, welche biologische und konventionelle Lebensmittel differenzieren können. Vor diesem Hintergrund war es das Ziel der Studie, die bestehenden oder in der Entwicklung befindlichen differenzierenden Methoden zur Unterscheidung biologisch von herkömmlich erzeugten Nahrungsmitteln zu beschreiben und ihre Praxistauglichkeit zu bewerten. Hierfür wurden eine umfangreiche Literaturstudie sowie ergänzende Expertengespräche durchgeführt

Perceiving molecular evolution processes in Escherichia coli by comprehensive metabolite and gene expression profiling

Transcript and metabolite abundance changes were analyzed in evolved and ancestor strains of Escherichia coli in three different evolutionary condition