Microbial transformation of neutral fraction and upgraded neutral fraction of Polish tall oil

Summary Microbial transformations of neutral fraction (NF) and upgraded neutral fraction (UNF) of Polish tall oil byMycobacterium sp. MB 3683 were performed. Final metabolites and yields were compared to bioconversion of pure -sitosterol. Additionally, origin of a new metabolite —5-androsta-3,6,17-trione was proved by transformation of UNF in the presence of labeled -sitosterol.     

Changes of phenolic secondary metabolite profiles in the reaction of narrow leaf lupin (Lupinus angustifolius) plants to infections with Colletotrichum lupini fungus or treatment with its toxin

Plant interactions with environmental factors cause changes in the metabolism and regulation of biochemical and physiological processes. Plant defense against pathogenic microorganisms depends on an innate immunity system that is activated as a result of infection. There are two mechanisms of triggering this system: basal immunity activated as a result of a perception of microbe-associated molecular patterns through pattern recognition receptors situated on the cell surface and effector-triggered immunity (ETI). An induced biosynthesis of bioactive secondary metabolites, in particular phytoalexins, is one of the mechanisms of plant defense to fungal infection. Results of the study on narrow leaf lupin (Lupinus angustifolius L.) plants infected with the anthracnose fungus Colletotrichum lupini and treated with fungal phytotoxic metabolites are described in the paper. The C. lupini phytotoxins were isolated from liquid cultures, purified and partially characterized with physicochemical methods. Accumulation of secondary metabolites on leaf surface and within the tissues of plants either infected, treated with the fungal phytotoxin or submitted to both treatments was studied using GC-MS and LC-MS, respectively. Substantial differences in isoflavone aglycones and glycoconjugate profiles occurred in response to different ways of plant treatment.     

A Cryptic Cytoplasmic Male Sterility Unveils a Possible Gynodioecious Past for Arabidopsis thaliana

Gynodioecy, the coexistence of hermaphrodites and females (i.e. male-sterile plants) in natural plant populations, most often results from polymorphism at genetic loci involved in a particular interaction between the nuclear and cytoplasmic genetic compartments (cytonuclear epistasis): cytoplasmic male sterility (CMS). Although CMS clearly contributes to the coevolution of involved nuclear loci and cytoplasmic genomes in gynodioecious species, the occurrence of CMS genetic factors in the absence of sexual polymorphism (cryptic CMS) is not easily detected and rarely taken in consideration. We found cryptic CMS in the model plant Arabidopsis thaliana after crossing distantly related accessions, Sha and Mr-0. Male sterility resulted from an interaction between the Sha cytoplasm and two Mr-0 genomic regions located on chromosome 1 and chromosome 3. Additional accessions with either nuclear sterility maintainers or sterilizing cytoplasms were identified from crosses with either Sha or Mr-0. By comparing two very closely related cytoplasms with different male-sterility inducing abilities, we identified a novel mitochondrial ORF, named orf117Sha, that is most likely the sterilizing factor of the Sha cytoplasm. The presence of orf117Sha was investigated in worldwide natural accessions. It was found mainly associated with a single chlorotype in accessions belonging to a clade predominantly originating from Central Asia. More than one-third of accessions from this clade carried orf117Sha, indicating that the sterilizing-inducing cytoplasm had spread in this lineage. We also report the coexistence of the sterilizing cytoplasm with a non-sterilizing cytoplasm at a small, local scale in a natural population; in addition a correlation between cytotype and nuclear haplotype was detected in this population. Our results suggest that this CMS system induced sexual polymorphism in A. thaliana populations, at the time when the species was mainly outcrossing.     

Helicobacter pylori infection and antioxidants can modulate the genotoxic effects of heterocyclic amines in gastric mucosa cells

Helicobacter pylori (H. pylori) infection plays an important role in gastric carcinogenesis. This bacterium may induce cancer transformation and change the susceptibility of gastric mucosa cells to various exogenous dietary irritants. The aim of the study was to evaluate the influence of H. pylori infection on the reaction of the stomach cells to a genotoxic effect of heterocyclic amines (HCAs). These well-known mutagens are formed during cooking of protein-rich foods, primarily meat. Taking into account that persons consuming a mixed-western diet are exposed to these compound nearly an entire lifetime and more than half of human population is infected with H. pylori, it is important to assess the combined effect of H. pylori infection and HCAs in the context of DNA damage in gastric mucosa cells, which is a prerequisite to cancer transformation. We employed 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,8-dimethyl-imidazo[4,5-f]quinoxaline (MeIQx) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) because these substances are present in a great amount in cooked and fried meat. Using alkaline comet assay, we showed that the extent of the DNA damage induced by HCAs was significantly higher in H. pylori infected gastric mucosa cells than in non-infected counterparts. We did not observed any difference in the efficiency of repair of DNA lesions induced by HCAs in both type of cells. Vitamin C reduced the genotoxic effects of HCAs in H. pylori infected and non-infected gastric mucosa cells. Melatonin more effectively decreased DNA damage caused by HCAs in H. pylori infected gastric mucosa cells as compared with control. Our results suggest that H. pylori infection may influence the susceptibility of gastric mucosa cells to HCAs and dietary antioxidative substances, including vitamin C and melatonin may inhibit the genotoxic effects of HCAs on gastric mucosa cells and may reduce the risk of carcinogenesis caused by food borne mutagens and H. pylori infection.     

Large BRCA1 and BRCA2 genomic rearrangements in Polish high-risk breast and ovarian cancer families

BRCA1 and BRCA2 are two major genes associated with familial breast and ovarian cancer susceptibility. In Poland standard BRCA gene test is usually limited to Polish founder BRCA1 mutations: 5382insC, C61G and 4153delA. To date, just a few single large genomic rearrangements (LGRs) of BRCA1 gene have been reported in Poland. Here we report the first comprehensive analysis of large mutations in BRCA1 and BRCA2 genes in this country. We screened LGRs in BRCA1 and BRCA2 genes by multiplex ligation-dependent probe amplification in 200 unrelated patients with strong family history of breast/ovarian cancers and negative for BRCA1 Polish founder mutations. We identified three different LGRs in BRCA1 gene: exons 13-19 deletion, exon 17 deletion and exon 22 deletion. No LGR was detected in BRCA2 genes. Overall, large rearrangements accounted for 3.7 % of all BRCA1 mutation positive families in our population and 1.5 % in high-risk families negative for Polish founder mutation.     

Co-expression pattern of dopamine beta-hydroxylase (DβH) and neuropeptide Y (NPY) within sympathetic innervation of ovary and umbilical cord of the European bison (Bison bonasus L.)

Co-expression of dopamine β-hydroxylase (DβH) and neuropeptide Y (NPY) has never been examined in ovary (OV) and umbilical cord (UC) of the European bison (Eb), the endangered wild species. The OV and UC samples were harvested from seasonally eliminated Eb females (45–120 days post coitum). Frozen histological sections were examined by double fluorescent immunohistochemistry (dF-IHC), using the primary mouse anti-DβH monoclonals and rabbit anti-NPY polyclonals and then the immunocomplexes were visualized with FITC and CY3 fluorophores, respectively. Numerous DβH immunoreactive nerve fibers (DβH-IRs) and a little less frequent NPY-IRs were found in the bundle-like structures, innervating mainly perivascular regions of the OV. The NPY-IRs constantly co-expressed DβH, while some DβH-IRs did not express NPY. This specific pattern of innervation was observed both in the stromal and cortical regions of the OV. The simultaneous co-expression of DβH and NPY were also detected in the UC, in which specific single or bundle-like structures ran along the smooth muscles of blood vessels. The spatial-specific co-expression of DβH and NPY in OV and UC, may suggest that these markers are involved in the control of vascularization that regulates nourishing blood circulation required for proper pregnancy maintenance and efficient embryo/fetus development in the Eb.     

Assessment of chemical-crosslink-assisted protein structure modeling in CASP13

With the advance of experimental procedures obtaining chemical crosslinking information is becoming a fast and routine practice. Information on crosslinks can greatly enhance the accuracy of protein structure modeling. Here, we review the current state of the art in modeling protein structures with the assistance of experimentally determined chemical crosslinks within the framework of the 13th meeting of Critical Assessment of Structure Prediction approaches. This largest-to-date blind assessment reveals benefits of using data assistance in difficult to model protein structure prediction cases. However, in a broader context, it also suggests that with the unprecedented advance in accuracy to predict contacts in recent years, experimental crosslinks will be useful only if their specificity and accuracy further improved and they are better integrated into computational workflows.     

Amino acid sequence and homology modeling of obtustatin,a novel non-RGD-containing short disintegrin isolated from the venom of Vipera lebetina obtusa

Disintegrins represent a group of cysteine-rich peptides occurring in Crotalidae and Viperidae snake venoms, and are potent antagonists of several integrin receptors. A novel disintegrin, obtustatin, was isolated from the venom of the Vipera lebetina obtusa viper, and represents the first potent and selective inhibitor of the binding of integrin alpha(1)beta(1) to collagen IV. The primary structure of obtustatin contains 41 amino acids and is the shortest disintegrin described to date. Obtustatin shares the pattern of cysteines of other short disintegrins. However, in contrast to known short disintegrins, the integrin-binding loop of obtustatin is two residues shorter and does not express the classical RGD sequence. Using synthetic peptides, a KTS motif was identified as the integrin-binding sequence. A three-dimensional model of obtustatin, built by homology-modeling structure calculations using different templates and alignments, strongly indicates that the novel KTS motif may reside at the tip of a flexible loop.