Rapid reactions of spruce cells to elicitors released from the ectomycorrhizal fungus Hebeloma crustuliniforme, and inactivation of these elicitors by extracellular spruce cell enzymes

Elicitors released from hyphae or cell walls of the ectomycorrhizal fungus Hebeloma crustuliniforme (Bull. ex Fries.) Quél. induced in suspension-cultured cells of Picea abies (L.) Karst. a set of fast reactions: (i) an immediate efflux of Cl^– into the medium, followed by a K⁺ efflux; (ii) an influx of Ca²⁺ (measured as accumulation of ⁴⁵Ca²⁺ in the cells); (iii) a phosphorylation of a 63-kDa protein and dephosphorylation of a 65-kDa protein (detectable by 4 min after elicitor application); (iv) an alkalinization of the medium, and (v) a transient synthesis of H₂O₂. The removal of extracellular Ca²⁺ by EGTA delayed the elicitor-induced alkalinization. A further reduction of this response could be achieved by TMB-8 an inhibitor of Ca²⁺ release from intracellular stores. Moreover, the inhibition of protein kinase activity by staurosporine prevented the extracellular alkalinization completely. However, the effectiveness of the elicitors in inducing the extracellular alkalinization was strongly impaired by constitutively secreted enzymes of spruce cells which cleaved the elicitors to inactive fragments. It is suggested that in ectomycorrhizae the efficacy of elicitors released from fungal cell walls is controlled by apoplastic enzymes of the host; the plant itself is able to reduce the activity of fungal elicitors on their way through the plant cell wall. But those elicitors which finally reach the plasma membrane of host cells induce reactions that are similar to the early defense reactions in plant-pathogen interactions.Abbreviations DW dry weight - FW fresh weight - TMB-8 3,4,5 trimethoxybenzoic acid 8-(diethylamino)-octyl ester We thank Prof. M. Zenk (Universität München, Germany) for providing spruce cell cultures, and Dr. I. Kottke (Universität Tübingen, Germany) for isolates of Hebeloma crustuliniforme Tü 704. We are also thankful to Dr. W. Mayer (Universität Tübingen) for valuble discussions. This work was supported by Deutsche Forschungsgemeinschaft. B. Zitterell-Haid was financed by Graduiertenkolleg Interaktion in Waldökosystemen (supported by Deutsche Forschungsgemeinschaft) and G. Hebe by a scholarship of the Landesgraduiertenförderungsgesetz.     

The biosynthesis of the lantibiotics epidermin,gallidermin, Pep5 and epilancin K7

Lantibiotics are antibiotic peptides that contain the rare thioether amino acids lanthionine and/or methyllanthionine. Epidermin, Pep5 and epilancin K7 are produced by Staphylococcus epidermidis whereas gallidermin (6L-epidermin) was isolated from the closely related species Staphylococcus gallinarum. The biosynthesis of all four lantibiotics proceeds from structural genes which code for prepeptides that are enzymatically modified to give the mature peptides. The genes involved in biosynthesis, processing, export etc. are found in gene clusters adjacent to the structural genes and code for transporters, immunity functions, regulatory proteins and the modification enzymes LanB, LanC and LanD, which catalyze the biosynthesis of the rare amino acids. LanB and LanC are responsible for the dehydration of the serine and threonine residues to give dehydroalanine and dehydrobutyrine and subsequent addition of cysteine SH-groups to the dehydro amino acids which results in the thioether rings. EpiD, the only LanD enzyme known so far, catalyzes the oxidative decarboxylation of the C-terminal cysteine of epidermin which gives the C-terminal S-aminovinylcysteine after addition of a dehydroalanine residue.Abbreviations Dha 2,3-didehydroalanine - Dhb 2,3-didehydrobutyrine - Lan lanthionine - Melan methyllanthionine     

Genetic Analysis of the Epidermal Differentiation Complex (EDC) on Human Chromosome 1q21: Chromosomal Orientation, New Markers, and a 6-Mb YAC Contig

The epidermal differentiation complex (EDC) unites a remarkable number of structurally, functionally, and evolutionarily related genes that play an important role in terminal differentiation of the human epidermis. It is localized within 2.05 Mb of region q21 on human chromosome 1. We have identified and characterized 24 yeast artificial chromosome (YAC) clones by mapping individual EDC genes, sequence-tagged site (STS) markers (D1S305, D1S442, D1S498, D1S1664), and 10 new region-specific probes (D1S3619–D1S3628). Here we present a contig that covers about 6 Mb of 1q21 including the entire EDC. Fluorescencein situhybridization on metaphase chromosomes with two YACs flanking the EDC determined its chromosomal orientation and established, in conjunction with physical mapping results, the following order of genes and STSs: 1cen–D1S442–D1S498–S100A10–THH–FLG–D1S1664–IVL–SPRR3–SPRR1–SPRR2–LOR–S100A9–S100A8–S100A7–S100A6–S100A5–S100A4–S100A3–S100A2–S100A1–D1S305–1qtel. These integrated physical, cytogenetic, and genetic mapping data will be useful for linkage analyses of diseases associated with region 1q21 and for the identification of novel genes and regulatory elements in the EDC.     

Membrane topology and mutational analysis of the TolQ protein of Escherichia coli required for the uptake of macromolecules and cell envelope integrity.

TolQ is a 230-amino-acid protein required to maintain the integrity of the bacterial envelope and to facilitate the import of both filamentous bacteriophage and group A colicins. Cellular fractionation experiments showed TolQ to be localized to the cytoplasmic membrane. Bacteria expressing a series of TolQ-beta-galactosidase and TolQ-alkaline phosphatase fusion proteins were analyzed for the appropriate enzyme activity, membrane location, and sensitivity to exogenously added protease. The results are consistent with TolQ being an integral cytoplasmic membrane protein with three membrane-spanning regions. The amino-terminal 19 residues as well as a small loop in the 155 to 170 residue region appear exposed in the periplasm, while the carboxy terminus and a large loop after the first transmembrane region are cytoplasmic. Amino-terminal sequence analysis of TolQ purified from the membrane revealed the presence of the initiating formyl methionine group, suggesting a rapid translocation of the amino-terminal region across the cytoplasmic membrane. Analysis of various tolQ mutant strains suggests that the third transmembrane region as well as parts of the large cytoplasmic loop are necessary for activity.     

Thiophene synthesis and distribution in young developing plants of Tagetes patula and Tagetes erecta

Thiophene synthesis and accumulation were investigated in organsof Tagetes patula and T. erecta. Thiophene accumulation startedrapidly in germinating seedlings of both species. Roots andhypocotyls were the major thiophene accumulating organs and5-(3-buten-1-ynyl)-2, 2-bithienyl (BBT) and 5-(4-acetoxy-1-butynyl)-2,2 -bithienyl (BBTOAc) were the major accumulated compounds.Higher thiophene concentrations were reached in Tagetes patulathan in T. erecta. Accumulation patterns for individual thiopheneswere different within organs, between organs and between bothspecies. Within hypocotyls of Tagetes patula, thiophene concentrationswere high in the epidermis and the vascular tissue and low inthe parenchymatic tissues of cortex and pith. Synthesis of thiopheneswas high in the roots and hypocotyls and very low in the leaves.Transport of thiophenes from the roots into the shoot occurred,but the rate of transport was too low to explain the high concentrationsin the hypocotyl. It is concluded that for the main part thiophenesare accumulated where they are synthesized. Key words: Tagetes, hiophenest, synthesis, accumulation, secondary metabolites     

Investigation of the dithiocarbamate-induced coupling of allylidene and carbonyl ligands on a tungsten center

Reaction of the allylidene tungsten complex [W(CPhCHCHMe)Br₂(CO)₂(4-picoline)] (1) with the dithiocarbamates MS₂CNR₂ (a: M=Na, R=Et; b: M=Na, R=Me; c: M=Li, R=Ph) in THF at 50 °C affords the vinylketene tungsten complexes [W(S₂CNR₂)₂(OCCPhCHCHMe)(CO)] (2a–c). At lower temperatures, four reaction intermediates (3–6) may be discerned. Spectroscopic studies indicate that these compounds contain η⁴-allyldithiocarbamate ligands which are generated by addition of dithiocarbamate across the metal-carbon double bond of the allylidene-tungsten unit in 1. The structures of [W(S₂CNEt₂)₂(OCCPhCHCHMe)(CO)] (2a) and of one intermediate, [W(η⁴-Et₂NCS₂CPhCHCHMe)(S₂CNEt₂)(CO)₂] (5a) were elucidated by X-ray crystallography.