Mapping QTLs for resistance against <Emphasis Type="Italic">Globodera pallida</Emphasis> (Stone) Pa2/3 in a diploid potato progeny originating from <Emphasis Type="Italic">Solanum spegazzinii</Emphasis>

A "F1" diploid population between Solanum tuberosum 2 x and the wild Solanum spegazzinii was studied. It segregated for resistance against the potato cyst nematode Globodera pallida derived from the wild species. The inheritance had a quantitative nature. Linkage maps of AFLP and RFLP markers were constructed for both parents. Three QTLs were identified on the map of the resistant parent on chromosomes V, VI and XII, respectively. The first one had a major effect and explained more than 50% of the total variance of resistance. It is located in a cluster of resistance genes and may be the same locus as Gpa which has been described formerly. The two others explained about 20% of the total variance each. The QTL on chromosome XII is also in a cluster of resistance genes, and in an orthologous position with resistance genes against nematodes in tomato and pepper.     

Enzymatic function of loop movement in enolase: preparation and some properties of H159N,H159A,H159F,and N207A enolases

The hypothesis that His159 in yeast enolase moves on a polypeptide loop to protonate the phosphoryl of 2-phosphoglycerate to initiate its conversion to phosphoenolpyruvate was tested by preparing H159N, H159A, and H159F enolases. These have 0.07%–0.25% of the native activity under standard assay conditions and the pH dependence of maximum velocities of H159A and H159N mutants is markedly altered. Activation by Mg²⁺ is biphasic, with the smaller Mg²⁺ activation constant closer to that of the catalytic Mg²⁺ binding site of native enolase and the larger in the mM range in which native enolase is inhibited. A third Mg²⁺ may bind to the phosphoryl, functionally replacing proton donation by His159. N207A enolase lacks an intersubunit interaction that stabilizes the closed loop(s) conformation when 2-phosphoglycerate binds. It has 21% of the native activity, also exhibits biphasic Mg²⁺ activation, and its reaction with the aldehyde analogue of the substrate is more strongly inhibited than is its normal enzymatic reaction. Polypeptide loop(s) closure may keep a proton from His159 interacting with the substrate phosphoryl oxygen long enough to stabilize a carbanion intermediate.     

Computational methods of analysis of protein-protein interactions

Computational methods play an important role at all stages of the process of determining protein-protein interactions. They are used to predict potential interactions, to validate the results of high-throughput interaction screens and to analyze the protein networks inferred from interaction databases.     

Calcium dysregulation in Alzheimer's disease

Alzheimer disease (AD) is the most common form of adult dementia. Its pathological hallmarks are synaptic degeneration, deposition of amyloid plaques and neurofibrillary tangles, leading to neuronal loss. A few hypotheses have been proposed to explain AD pathogenesis. The beta-amyloid (Abeta) and hyperphosphorylated tau hypotheses suggest that these proteins are the main players in AD development. Another hypothesis proposes that the dysregulation of calcium homeostasis may be a key factor in accelerating other pathological changes. Although Abeta and tau have been extensively studied, recently published data provide a growing body of evidence supporting the critical role of calcium signalling in AD. For example, presenilins, which are mutated in familial cases of AD, were demonstrated to form low conductance calcium channels in the ER and elevated cytosolic calcium concentration increases amyloid generation. Moreover, memantine, an antagonist of the NMDA-calcium channel receptor, has been found to have a beneficial effect for AD patients offering novel possibilities for a calcium signalling targeted therapy of AD. This review underscores the growing importance of calcium ions in AD development and focuses on the relevant aspects of calcium homeostasis.     

The activity of selected glycosidases in salivary gland tumors

The monitoring of the patients after salivary gland tumors surgery is an important clinical issue. Still imperfect diagnostic procedures also remain a challenge for searching new sensitive and specific biomarkers of neoplastic processes in salivary glands. The aim of the presented study was an the assessment of the activity of HEX, with its isoforms HEX-A and HEX-B, GLU, GAL, MAN and FUC in salivary gland tumor tissues in comparison to a healthy salivary gland tissues taken during autopsy. A group of 42 patients with benign and malignant salivary gland tumors, aged 25-65 were examined. Fragments of salivary gland tumor tissue, fragments of healthy tissue removed during autopsy, blood serum and saliva were collected from patients with salivary gland tumors and healthy volunteers. In salivary gland tumor tissue the activity of HEX, HEX-A, HEX-B, GAL, FUC was considerably higher than in comparison to healthy salivary gland tissue and ascending trend of activity of GLU, MAN was also noticed. The activity of all lysosomal exoglycosidases in blood serum in patients with salivary gland tumors was considerably higher in comparison to healthy volunteers blood serum. The considerably higher activity of HEX, HEX-A, GLU, GAL, MAN, FUC and descending trend of activity of HEX-B were noticed in saliva of patients with salivary gland tumors in comparison to healthy volunteers. The assessment of HEX in blood serum and saliva of patients with salivary gland tumor can be possibly used in diagnostics and monitoring of salivary glands tumors.     

Septins enforce morphogenetic events during sexual reproduction and contribute to virulence of Cryptococcus neoformans

Septins are conserved, cytoskeletal GTPases that contribute to cytokinesis, exocytosis, cell surface organization and vesicle fusion by mechanisms that are poorly understood. Roles of septins in morphogenesis and virulence of a human pathogen and basidiomycetous yeast Cryptococcus neoformans were investigated. In contrast to a well‐established paradigm in S. cerevisiae, Cdc3 and Cdc12 septin homologues are dispensable for growth in C. neoformans yeast cells at 24°C but are essential at 37°C. In a bilateral cross between septin mutants, cells fuse but the resulting hyphae exhibit morphological abnormalities, including lack of properly fused specialized clamp cells and failure to produce spores. Interestingly, post‐mating hyphae of the septin mutants have a defect in nuclear distribution. Thus, septins are essential for the development of spores, clamp cell fusion and also play a specific role in nuclear dynamics in hyphae. In the post‐mating hyphae the septins localize to discrete sites in clamp connections, to the septa and the bases of the initial emerging spores. Strains lacking CDC3 or CDC12 exhibit significantly reduced virulence in a Galleria mellonella model of infection. Thus, C. neoformans septins are vital to morphology of the hyphae and contribute to virulence.     

The minimum information required for reporting a molecular interaction experiment (MIMIx)

A wealth of molecular interaction data is available in the literature, ranging from large-scale datasets to a single interaction confirmed by several different techniques. These data are all too often reported either as free text or in tables of variable format, and are often missing key pieces of information essential for a full understanding of the experiment. Here we propose MIMIx, the minimum information required for reporting a molecular interaction experiment. Adherence to these reporting guidelines will result in publications of increased clarity and usefulness to the scientific community and will support the rapid, systematic capture of molecular interaction data in public databases, thereby improving access to valuable interaction data.