Books and chapters
Wrenger, S.; Reinhold, D.; Faust, J.; Mrestani-Klaus, C.; Brandt, W.; Fengler, A.; Neubert, K.; Ansorge, S.; Effects of Nonapeptides Derived From the N-terminal Structure of Human Immunodeficiency Virus-1 (HIV-1) Tat on Suppression of CD26-Dependent T Cell Growth Adv. Exp. Med. Biol. 477, 161-165, (2002) ISBN: 978-0-306-46826-1 DOI: 10.1007/0-306-46826-3_18
The human immunodeficiency virus-1 (HIV-1) transactivator Tat occurs extracellularly and exerts immunosuppressive effects. Interestingly, Tat inhibits dipeptidyl peptidase IV (DP IV) activity of the T cellactivation marker CD26. The short N-terminal nonapeptideTat(l-9), MDPVDPNIE, also inhibits DP IV activity and suppresses DNA synthesis of tetanus toxoid-stimulated peripheral blood mononuclear cells (PBMC). Here, we present the influence of amino acid exchanges in the first three positions of Tat(l-9). For instance, the replacement of D2 of Tat(l-9) by G or K generated peptides, which inhibit DP IV-catalyzed IL-2(1-12) cleavage nearly threefold stronger. Similar effects were observed on the suppression of DNA synthesis of Tetanus toxoid-stimulated PBMC. This correlation suggests that Tat(l-9)-deduced peptides mediate antiproliferative effects at least in part via specific DP IV interactions and supports the hypothesis that CD26 plays a key role in the regulation of lymphocyte growth.
Books and chapters
Wasternack, C.; Hause, B.; Jasmonates and octadecanoids: Signals in plant stress responses and development Prog. Nucleic Acid Res. Mol. Biol. 72, 165-221, (2002) DOI: 10.1016/S0079-6603(02)72070-9
Plants are sessile organisms. Consequently they have to adapt constantly to fluctuations in the environment. Some of these changes involve essential factors such as nutrients, light, and water. Plants have evolved independent systems to sense nutrients such as phosphate and nitrogen. However, many of the environmental factors may reach levels which represent stress for the plant. The fluctuations can range between moderate and unfavorable, and the factors can be of biotic or abiotic origin. Among the biotic factors influencing plant life are pathogens and herbivores. In case of bacteria and fungi, symbiotic interactions such as nitrogen-fixating nodules and mycorrhiza, respectively, may be established. In case of insects, a tritrophic interaction of herbivores, carnivores, and plants may occur mutualistically or parasitically. Among the numerous abiotic factors are low temperature, frost, heat, high light conditions, ultraviolet light, darkness, oxidation stress, hypoxia, wind, touch, nutrient imbalance, salt stress, osmotic adjustment, water deficit, and desiccation.In the last decade jasmonates were recognized as being signals in plant responses to most of these biotic and abiotic factors. Signaling via jasmonates was found to occur intracellularly, and systemically as well as interorganismically. Jasmonates are a group of ubiquitously occurring plant growth regulators originally found as the major constituents in the etheric oil of jasmine, and were first suggested to play a role in senescence due to a strong senescence-promoting effect. Subsequently, numerous developmental processes were described in which jasmonates exhibited hormone-like properties. Recent knowledge is reviewed here on jasmonates and their precursors, the octadecanoids. After discussing occurrence and biosynthesis, emphasis is placed upon the signal transduction pathways in plant stress responses in which jasmonates act a signal. Finally, examples are described on the role of jasmonates in developmental processes.
Books and chapters
Kutchan, T. M.; Schröder, J.; Selected cell cultures and induction methods for cloning and assaying cytochromes P450 in alkaloid pathways Methods Enzymol. 357, 370-381, (2002) DOI: 10.1016/S0076-6879(02)57695-3
This chapter focuses on selected cell cultures and induction methods for cloning and assaying cytochromes P450 in alkaloid pathways. The biosynthesis of selected members of alkaloid classes for which the enzymatic steps are elucidated in the chapter, such as the monoterpenoid indole alkaloid vindoline and the isoquinoline alkaloids morphine, macarpine, and berberine, involves highly substrate-specific cytochromes P450. Although in vitro enzyme assays have been successfully developed for most of these cytochromes P450, purification to apparent homogeneity of cytochromes P450 from plant tissues has, in many cases, proved elusive because of the low abundance and instability of these proteins. Because many alkaloid biosynthetic pathways can be induced in plant cell culture, the differential expression of cytochrome P450 encoding genes involved in these pathways can be exploited in the cloning of these genes. The protocols described in the chapter are used successfully in the laboratories to clone and functionally express cytochrome P450-encoding cDNAs of alkaloid biosynthesis.
Books and chapters
Being surrounded by putatively hostile microorganisms, but immobile and hence unable to escape, plants constantly need to be prepared for defensive battle. During their coevolution with heterotrophic parasites they have therefore acquired efficient passive, preformed barriers that provide protection against the majority of aggressors. In addition, however, plants have an arsenal of offensive weapons for counterattack at their disposal once the passive bulwark has failed. Usually, this weaponry is launched rapidly and decisively, thus negating any further progression of the invader in order to maintain the plant’s structural and functional integrity.
Books and chapters
Fengler, A.; Brandt, W.; Development and Validation of Homology Models of Human Cathepsins K, S, H, and F Adv. Exp. Med. Biol. 477, 255-260, (2002) ISBN: 978-0-306-46826-1 DOI: 10.1007/0-306-46826-3_27
Models of the tertiary structures of cathepsins K, S, H, and F were constructed by using homology protein modelling methods and refinements by interactive graphics and energy minimisation. The predicted structures yield information regarding their substrate binding sites and indicate the residues surrounding these sites. The ligandbinding sites were characterised and compared with each other by means of calculated molecular electrostatic surface potentials. This will allow designing and development of new ligands specific for these cathepsins in future investigations.
Books and chapters
Faust, J.; Wrenger, S.; Reinhold, D.; Kähne, T.; Lorey, S.; Stöckel-Maschek, A.; Brandt, W.; Mrestani-Klaus, C.; Stiebitz, B.; Fuchs, P.; Ansorge, S.; Neubert, K.; Down regulation of T-cell activation by synthetic dipeptidyl peptidase IV inhibitors with the N.terminal MXP sequence (Bendetti, E. & Predone, C., eds.). 750-751, (2002)
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