The relationship between airborne pollen and fungal spore concentrations and seasonal pollen allergy symptoms in Cracow in 1997–1999

The investigation of airborne pollen and fungalspore concentrations was carried out in Cracowbetween 1997–1999. For this study thevolumetric method has been employed (Burkard).At the same time the clinical diagnosis ofpollen allergy in 40 patients was obtained onthe basis of an interview, positive skin pricktests with pollen extracts and increasedspecific IgE level. An increase in seasonalallergy symptoms in all patients occurred fromthe middle of May to the middle of August.Eighty eight percent of the patients (35 out of40) were sensitive to Poaceae pollen and about50% of them were additionally sensitive totree and herb pollen excluding grasses. Forpatients with additional allergy to tree pollenthe seasonal symptoms started at the end ofMarch (Betula) while for patients withadditional allergy to herb pollen it wasextended to the middle of September (Artemisia).Five people out of 40 revealed positive skinreactions to Alternaria spores and anincrease in specific IgE level. Positive skinreaction to Cladosporium spores with noincrease in specific IgE level occurred in 2patients. The increase in seasonal allergysymptoms in people sensitive to Alternariaspores noted in July and August could becaused not only by these spores but also byPoaceae pollen.     

Molecular basis of inherited predispositions for tumors

On the basis of literature data and own experience the authors review the current knowledge about the molecular basis of inherited predispositions for tumors. They hypothesize that in the near perspective 5-10 years studies using existing registry data/material and the latest novel technology will allow the identification of the molecular background for the majority of hereditary cancers which will have enormous practical consequences especially for the prevention of malignancies.     

Crystal structures of two homologous pathogenesis-related proteins from yellow lupine

Pathogenesis-related class 10 (PR10) proteins are restricted to the plant kingdom where they are coded by multigene families and occur at high levels. In spite of their abundance, their physiological role is obscure although members of a distantly related subclass (cytokinin-specific binding proteins) are known to bind plant hormones. PR10 proteins are of special significance in legume plants where their expression patterns are related to infection by the symbiotic, nitrogen-fixing bacteria. Here we present the first crystal structures of classic PR10 proteins representing two homologues from one subclass in yellow lupine. The general fold is similar and, as in a birch pollen allergen, consists of a seven-stranded beta-sheet wrapped around a long C-terminal helix. The mouth of a large pocket formed between the beta-sheet and the helix seems a likely site for ligand binding. The shape of the pocket varies because, in variance with the rigid beta-sheet, the helix shows unusual conformational variability consisting in bending, disorder, and axial shifting. A surface loop, proximal to the entrance to the internal cavity, shows an unusual structural conservation and rigidity in contrast to the high glycine content in its sequence. The loop is different from the so-called glycine-rich P-loops that bind phosphate groups of nucleotides, but it is very likely that it does play a role in ligand binding in PR10 proteins.     

Enantioselective chromatography of alkyl derivatives of 5-ethyl-5-phenyl-2-thiobarbituric acid studied by semiempirical AM1 method

Complexation of alkyl derivatives of 5-ethyl-5-phenyl-2-thiobarbituric acid (2-thiophenobarbital) enantiomers by beta-cyclodextrin was investigated by the AM1 method. The inclusion complexes of beta-cyclodextrin with neutral and anionic forms of these enantiomers have been modeled and energetically optimized. The chiral discrimination of enantiomers was analyzed in terms of differences in the interaction energies. The calculated interaction energies between each enantiomer of the investigated 2-thiobarbiturates and beta-cyclodextrin confirm the ability of beta-cyclodextrin to act as a mobile phase additive in reversed-phase HPLC to separate enantiomers by liquid chromatography and rationalize their order of elution.     

Induction of light emission by luminescent bacteria treated with UV light and chemical mutagens

Intensity of light emission by luminescent bacteria in response to UV irradiation and chemical mutagens was tested. We demonstrated that luminescence of six strains of marine bacteria (belonging to four species: Photobacterium leiognathi, P. phosphoreum, Vibrio fischeri and V. harveyi) is significantly increased by UV irradiation relatively shortly after dilution of cultures. Such a stimulation of luminescence was abolished in cells treated with chloramphenicol 15 min before UV irradiation, indicating that effective gene expression is necessary for UV-mediated induction of light emission. These results suggest that stimulation of luminescence in UV-irradiated bacterial cells may operate independently of the quorum sensing regulation. A significant induction of luminescence was also observed upon treatment of diluted cultures of all investigated strains with chemical mutagens: sodium azide (SA), 2-methoxy-6-chloro-9-(3-(2-chloroethyl)aminopropylamino)acridine x 2HCl (ICR-191), 4-nitro-o-phenylenediamine (NPD), 4-nitroquinolone-N-oxide (NQNO), 2-aminofluorene (2-AF), and benzo[alpha]pyrene. These results support the proposal that genes involved in bioluminescence belong to the SOS regulon. The use of bacterial luminescence systems in assays for detection of mutagenic compounds is discussed in the light of this proposal.     

Further evidence for the importance of lipid bilayers in the interaction between lactate dehydrogenase and phosphatidylserine

Lactate dehydrogenase (LDH) is one of the glycolytic enzymes, which have been proved to have the capability to reverse non-specific adsorption on cellular membranous structures in vitro, as well as on the structural proteins of the contractile system of muscle cells. It has been suggested that this binding may play a physiological role, as it alters the enzyme's kinetic properties. Our previous studies on this enzyme showed that its interaction with some anionic phospholipids reveals similar characteristics and similar effect on the activity of the enzyme to those which had been observed for the interaction with membranous structures. Disruption of the lipid bilayers by nonionic detergent (Tween 20) restored the enzyme activity inhibited by the presence of phosphatidylserine (PS) liposomes. In this study, we used the measurement of enzyme tryptophanyl fluorescence spectra to monitor the interaction and possible changes in the enzyme conformation. The investigation provided further evidence of the importance of the bilayer structure in this interaction. Similarly to the effect on the activity of the enzyme, the addition of Tween 20 diminishes the quenching of the LDH tryptophanyl fluorescence, and finally completely restores the fluorescence.     

A model for regulation of ColE1-like plasmid replication by uncharged tRNAs in amino acid-starved Escherichia coli cells

It has been previously observed that various ColE1-like plasmids replicate differentially in Escherichia coli cells during the relaxed response to amino acid starvation. Here we develop a kinetic model to explain these observations based on the possibility of interaction of the 3' CCA-OH sequence with the UGG triplets in loops of RNA I and RNA II encoded by ColE1-like plasmids. According to our model, when the interaction of uncharged CCA with RNA I is possible, the replication of the ColE1-like plasmid is affected by differences in the concentration of various tRNAs in the starved cell, but it is not affected by the tRNA concentration if the hypothetical pairing occurs between the CCA-OH and RNA II. Using the previously determined parameters for the pBR322 plasmid, the concentration of uncharged tRNAs in the amino acid starved relaxed strains and the assumed efficiency of binding of tRNA and RNA I, we show that our model explains the differences in pBR322 copy number in the relaxed strain starved for several amino acids.     

Characterization of RAD51-independent break-induced replication that acts preferentially with short homologous sequences

Repair of double-strand breaks by gene conversions between homologous sequences located on different Saccharomyces cerevisiae chromosomes or plasmids requires RAD51. When repair occurs between inverted repeats of the same plasmid, both RAD51-dependent and RAD51-independent repairs are found. Completion of RAD51-independent plasmid repair events requires RAD52, RAD50, RAD59, TID1 (RDH54), and SRS2 and appears to involve break-induced replication coupled to single-strand annealing. Surprisingly, RAD51-independent recombination requires much less homology (30 bp) for strand invasion than does RAD51-dependent repair (approximately 100 bp); in fact, the presence of Rad51p impairs recombination with short homology. The differences between the RAD51- and RAD50/RAD59-dependent pathways account for the distinct ways that two different recombination processes maintain yeast telomeres in the absence of telomerase.