Martina Marchetti

Epl1, the major secreted protein of Hypocrea atroviridis on glucose, is a member of a strongly conserved protein family comprising plant defense response elicitors.

We used a proteomic approach to identify constitutively formed extracellular proteins of Hypocrea atroviridis (Trichoderma atroviride), a known biocontrol agent. The fungus was cultivated on glucose and the secretome was examined by two‐dimensional gel electrophoresis. The two predominant spots were identified by MALDI MS utilizing peptide mass fingerprints and amino acid sequence tags obtained by postsource decay and/or high‐energy collision‐induced dissociation (MS/MS) experiments, and turned out to be the same protein (12 629 Da as determined with MS, pI 5.5–5.7), probably representing the monomer and the dimer. The corresponding gene was subsequently cloned from H. atroviridis and named epl1 (eliciting plant response‐like), because it encodes a protein that exhibits high similarity to the cerato‐platanin family, which comprises proteins such as cerato‐platanin from Ceratocystis fimbriata f. sp. platani and Snodprot1 of Phaeosphaeria nodorum, which have been reported to be involved in plant pathogenesis and elicitation of plant defense responses. Additionally, based on the similarity of the N‐terminus to that of H. atroviridis Epl1, we conclude that a previously identified 18 kDa plant response elicitor isolated from T. virens is an ortholog of epl1. Our results showed that epl1 transcript was present under all growth conditions tested, which included the carbon sources glucose, glycerol, l‐arabinose, d‐xylose, colloidal chitin and cell walls of the plant pathogen Rhizoctonia solani, and also plate confrontation assays with R. solani. Epl1 transcript could even be detected under osmotic stress, and carbon and nitrogen starvation.

Biological Variation of the Platelet Proteome in the Elderly Population and Its Implication for Biomarker Research

Knowledge about the extent of total variation experienced between samples from different individuals is of great importance for the design of not only proteomics but every clinical study. This variation defines the smallest statistically significant detectable signal difference when comparing two groups of individuals. We isolated platelets from 20 healthy human volunteers aged 56–100 years because this age group is most commonly encountered in the clinics. We determined the technical and total variation experienced in a proteome analysis using two-dimensional DIGE with IPGs in the pI ranges 4–7 and 6–9. Only spots that were reproducibly detectable in at least 90% of all gels (n = 908) were included in the study. All spots had a similar technical variation with a median coefficient of variation (cv) of about 7%. In contrast, spots showed a more diverse total variation between individuals with a surprisingly low median cv of only 18%. Because most known biomarkers show an effect size in a 1–2-fold range of their cv, any future clinical proteomics study with platelets will require an analytical method that is able to detect such small quantitative differences. In addition, we calculated the minimal number of samples (sample size) needed to detect given protein expression differences with statistical significance.

Characterization of the bga1-encoded glycoside hydrolase family 35 β-galactosidase of Hypocrea jecorina with galacto-β-d-galactanase activity

The extracellular bga1‐encoded β‐galactosidase of Hypocrea jecorina (Trichoderma reesei) was overexpressed under the pyruvat kinase (pki1) promoter region and purified to apparent homogeneity. The monomeric enzyme is a glycoprotein with a molecular mass of 118.8 ± 0.5 kDa (MALDI‐MS) and an isoelectric point of 6.6. Bga1 is active with several disaccharides, e.g. lactose, lactulose and galactobiose, as well as with aryl‐ and alkyl‐β‐d‐galactosides. Based on the catalytic efficiencies, lactitol and lactobionic acid are the poorest substrates and o‐nitrophenyl‐β‐d‐galactoside and lactulose are the best. The pH optimum for the hydrolysis of galactosides is ∼ 5.0, and the optimum temperature was found to be 60 °C. Bga1 is also capable of releasing d‐galactose from β‐galactans and is thus actually a galacto‐β‐d‐galactanase. β‐Galactosidase is inhibited by its reaction product d‐galactose and the enzyme also shows a significant transferase activity which results in the formation of galacto‐oligosaccharides.

Adaptive cellular mechanisms in response to glutamine-starvation.

Glutamine (Gln) utilising cells suffer from Gln-starvation during critical illness when plasma Gln levels are decreased. This study investigates whether such cells activate adaptive mechanisms. Monocytic U937 cells were cultured at 0.6 and 0.2 mM Gln for up to four days. Within the first day a decrease of ATP (78% of control), intracellular free Gln (13%), Hsp70 (74%) and proliferation rate (79%) was observed. A prolonged culture at 0.6 mM Gln for additional three days led to a recovery of ATP (97%), Hsp70 (91%) and proliferation (92%). The intracellular free Gln increased only to 41%. At 0.2 mM Gln, however, all levels remained decreased. The activation of the metabolic sensor AMP activated kinase (AMPK) increased immediately in Gln-starving cells but regained normal values only in cells cultured at 0.6 mM. A proteomic analysis identified 23 proteins, which were affected by Gln starvation including metabolic enzymes, proteins involved in synthesis and degradation of RNA and proteins, and stress proteins. These data show that Gln-utilising cells activate adaptive mechanisms in response to Gln-starvation, which enable them to overcome a Gln shortage. At very low Gln concentrations, these adaptive mechanisms are not sufficient to countervail the lack of the amino acid.

Synthesis of new tricyclic spirobispidines via ring closing metathesis reaction

New tricyclic spiro compounds based on 3,7-diazabicyclo[3.3.1]-nonane (bispidine) were synthesized by ruthenium-catalyzed ring closing metathesis reactions. The constitution of the newly formed double bond depending on the chain length and various conditions of the RCM reaction was analyzed.

Mass spectrometry of proteinous allergens inducing human diseases

Publisher Summary This chapter explores the role of mass spectrometry in the identification of particular allergens and of the reaction the human body stages to the flowers and other parts of the elderberry tree. Nine patients with a long history in summer hay fever were tested for symptoms after inhalative and dietary contact with elderberry products. All of them reported rhinoconjunctivitis; four of them even exhibited asthmatic symptoms. As patients may be exposed to the allergens hailing from Sambucus nigra via the oral route—flowers and fruits have been used in plant remedies and food for centuries—it has been of special interest that one patient developed upper-airway obstruction when drinking elderberry juices. Four patients showed strong reactions after skin prick tests (SPT), medium response was observed in two cases, and negative results were received for three persons including the patient exhibiting airway obstruction. IgE serum levels measured by radioallergosorbent tests (RAST) also varied significantly. In some cases no serum IgE was detectable; in another case up to 4080 kU/L was measured. The fuzzy characteristic of the immuno-detected spots after 2D gel electrophoresis pointed out that the allergy elicitor may be just one protein, posttranslationally modified, such as by carbohydrate moieties, or that the immunological response results from highly homologous proteins with just minor variation in their polypeptide sequence.