Karyological analysis of an interspecific hybrid between the dioecious Silene latifolia and the hermaphroditic Silene viscosa.

The genus Silene is a good model for studying evolution of the sex chromosomes, since it includes species that are hermaphroditic and dioecious, while maintain a basic chromosome number of 2n = 24. For some combinations of Silene species it is possible to construct interspecific hybrids. Here, we present a detailed karyological analysis of a hybrid between the dioecious Silene latifolia as the maternal plant and a related species, hermaphroditic Silene viscosa, used as a pollen partner. Using genomic probes (the genomic in situ hybridization (GISH) technique), we were able to clearly discriminate parental genomes and to show that they are largely separated in distinct nuclear domains. Molecular GISH and fluorescence in situ hybridization (FISH) markers document that the hybrid genome of somatic cells was strictly additive and stable, and that it had 12 chromosomes originating from each parent, including the only X chromosome of S. latifolia. Meiotic analysis revealed that, although related, respective parental chromosomes did not pair or paired only partially, which resulted in frequent chromosome abnormalities such as bridges and irregular non-disjunctions. GISH and FISH markers clearly document that the larger genome of S. latifolia and its largest chromosome component, the X chromosome, were mostly employed in chromosome lagging and misdivision.     

Proteomic analysis of shoot-borne root initiation in maize (Zea mays L.)

Postembryonically formed shoot-borne roots make up the major backbone of the adult maize root stock. In this study the abundant soluble proteins of the first node (coleoptilar node) of wild-type and mutant rtcs seedlings, which do not initiate crown roots, were compared at two early stages of crown root formation. In Coomassie Bluestained 2-D gels, representing soluble proteins of coleoptilar nodes 5 and 10 days after germination, 146 and 203 proteins were detected, respectively. Five differentially accumulated proteins (> two-fold change; t-test: 95% significance) were identified in 5-day-old and 14 differentially accumulated proteins in 10-day-old coleoptilar nodes of wild-type versus rtcs. All 19 differentially accumulated proteins were identified via ESI MS/MS mass spectrometry. Five differentially accumulated proteins, including a regulatory G-protein and a putative auxin-binding protein, were further analyzed at the RNA expression level. These experiments confirmed differential gene expression and revealed subtle developmental regulation of these genes during early coleoptilar node development. This study represents the first proteomic analysis of shoot-borne root initiation in cereals and will contribute to a better understanding of the molecular basis of this developmental process unique to cereals.     

Engineering of PA-IIL lectin from <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> – Unravelling the role of the specificity loop for sugar preference

Background  

Lectins are proteins of non-immune origin capable of binding saccharide structures with high specificity and affinity. Considering the high encoding capacity of oligosaccharides, this makes lectins important for adhesion and recognition. The present study is devoted to the PA-IIL lectin from Pseudomonas aeruginosa, an opportunistic human pathogen capable of causing lethal complications in cystic fibrosis patients. The lectin may play an important role in the process of virulence, recognizing specific saccharide structures and subsequently allowing the bacteria to adhere to the host cells. It displays high values of affinity towards monosaccharides, especially fucose – a feature caused by unusual binding mode, where two calcium ions participate in the interaction with saccharide. Investigating and understanding the nature of lectin-saccharide interactions holds a great potential of use in the field of drug design, namely the targeting and delivery of active compounds to the proper site of action.     

Autophagic cell death induced by TrkA receptor activation in human glioblastoma cells

The neurotrophin receptor tropomyosin-related kinase A (TrkA) and its ligand nerve growth factor (NGF) are expressed in astrocytomas, and an inverse association of TrkA expression with malignancy grade was described. We hypothesized that TrkA expression might confer a growth disadvantage to glioblastoma cells. To analyze TrkA function and signaling, we transfected human TrkA cDNA into the human glioblastoma cell line G55. We obtained three stable clones, all of which responded with striking cytoplasmic vacuolation and subsequent cell death to NGF. Analyzing the mechanism of cell death, we could exclude apoptosis and cellular senescence. Instead, we identified several indications of autophagy: electron microscopy showed typical autophagic vacuoles; acridine orange staining revealed acidic vesicular organelles; acidification of acidic vesicular organelles was prevented using bafilomycin A1; cells displayed arrest in G2/M; increased processing of LC3 occurred; vacuolation was prevented by the autophagy inhibitor 3-methyladenine; no caspase activation was detected. We further found that both activation of ERK and c-Jun N-terminal kinase but not p38 were involved in autophagic vacuolation. To conclude, we identified autophagy as a novel mechanism of NGF-induced cell death. Our findings suggest that TrkA activation in human glioblastomas might be beneficial therapeutically, especially as several of the currently used chemotherapeutics also induce autophagic cell death.     

Cytokine profiles of HeLa and human diploid cells induced by different fractions of Vibrio parahaemolyticus cultures exposed to stress conditions

Vibrio (V.) parahaemolyticus is an aquatic halophilic bacteria which produces gastroenteritis and in rare cases septicaemia after the consumption of raw or under-cooked contaminated seafood.The severity of diarrheal illness caused by this bacterium is closely related to the presence of two types of hemolysins (the thermostable direct hemolysin-TDH and TDH related hemolysin-TRH) and also of type III secretion system (TTSS) proteins. The TTSS type 1 induces a wide array of effects on infected HeLa cells such as autophagy, oncosis, cell rounding and lysis. Previous studies have shown that heat shock proteins have the ability to stimulate the production of interleukins in different cellular cultures. In our studies we have stimulated two cellular lines (HeLa and human diploid cells) with different V. parahaemolyticus culture fractions in order to observe the effect on cytokines production. Thus, the purpose of this study was to analyze the expression of IL-1, IL-2, IL-4, IL-6, IL-10 and TNF-alpha induced by the cell treatment with total cellular lysate, periplasmic fractions and culture supernatants extracted from V. parahaemolyticus exposed to normal and also to stress conditions. The ELISA assay of the cytokine profile of the HeLa and HDC cell lines stimulated with different bacterial fractions revealed that in the V. parahemolyticus cultures submitted to osmotic and heat shock stress are accumulating factors (probably heat shock proteins) which are exhibiting immunomodulatory activity, responsible for the induction of a pro-inflammatory response associated with increased levels of IL-6 and TNF-alpha expression, however balanced by the stimulation of the anti-inflammatory cytokine IL-4 synthesis.     

Abundance,distribution, and territory areas of rock-dwelling Lake Tanganyika cichlid fish species

Lake Tanganyika, the second-oldest and second-deepest lake in the world, harbors an impressive cichlid fish fauna counting about 250 endemic species that are characterized by a great level of ecological, morphological, and behavioral specialization. This study describes and compares cichlid fish communities at two rocky shores with differential human impact in the south of Lake Tanganyika. Species inventories and depth-dependent abundances were elaborated. About 41 and 46 sympatric cichlid species were recorded in the two study sites, respectively. Variabilichromis moorii was the most abundant species (29–60% of total number of fishes), followed by Aulonocranus dewindti (3–19%), Tropheus moorii (12%), Ophthalmotilapia ventralis (4–10%), Eretmodus cyanostictus (6–11%), and Cyathopharynx furcifer (0.01–9%). All other species had abundances below 5%. It further emerged that large cichlids such as Petrochromis species, Cyathopharynx furcifer, and Lobochilotes labiatus were very rare at one location, with frequencies of 0.55% or less. Territorial sizes of three particularly abundant species, Variabilichromis moorii, Aulonocranus dewindti, and Tropheus moorii, were assessed by behavioral observations. We distinguished between territorial core areas and total defended area, yielding average core areas between 0.4 (V. moorii) and 1.6 m² (T. moorii), and total defended areas averaging for each species between 1.6 (V. moorii) and 5.0 m² (A. dewindti) with no significant differences between the two study sites. The data on individual densities are also relevant for evolutionary studies, in that they allow more accurate calculations of effective population sizes.     

Response to oxidative stress as a welfare parameter in swine

In pigs, the genetic selection for lean, large muscle blocks and fast growth has been linked to an increased prevalence of metabolic diseases such as porcine stress syndrome and mulberry heart disease. These diseases are associated with cardiovascular inadequacy, which may lead to oxidative stress. In the present study, reactive oxygen metabolites (ROMs) and the anti-oxidant power (OXY) in sera of different swine groups were investigated. The following groups were selected (each around 80 kg body weight): wild boars (WB), Cinta Senese (CS), and Landrace x Large White (LxLW), the latter as both specific pathogen-free (SPF) and intensively farmed animals. In addition, a group of LxLW agonic sows (AS) was also investigated; this group is known to be under oxidative stress. Two colorimetric micro-methods were used to measure ROMs and OXY; ROMs were expressed as mM H(2)O(2) and OXY as microM HOCl neutralised. Between groups, average ROM and OXY values were found to be significantly different by one-way ANOVA (P < 0.001). ROM levels were lower in WB (13.41 +/- 1.85) and CS (19.27 +/- 1.68), and highest in LxLW (42.00 +/- 1.36). OXY values ranged from 260.10 +/- 22.13 (WB) to 396.90 +/- 9.83 (LxLW). Only one swine group (the CS group) showed a significant, positive correlation between ROM and OXY values. The AS group even showed a negative correlation between ROM and OXY values. These results imply satisfactory environmental coping occurred only within the CS group. Results are discussed in the light of animal welfare legislation, food safety and consumers' protection.     

Synthesis and antimycobacterial properties of N-substituted 6-amino-5-cyanopyrazine-2-carboxamides

A series of fifteen new compounds related to pyrazinamide (PZA) were synthesized, characterized with analytical data and screened for antimycobacterial, antifungal and antibacterial activity. The series consists of 6-chloro-5-cyanopyrazine-2-carboxamide and N-substituted 6-amino-5-cyanopyrazine-2-carboxamides, derived from the previous by nucleophilic substitution with various non-aromatic amines (alkylamines, cycloalkylamines, heterocyclic amines). Some of the compounds exerted antimycobacterial activity against Mycobacterium tuberculosis equal to pyrazinamide (12.5-25 μg/mL). More importantly, 6-chloro-5-cyanopyrazine-2-carboxamide and 5-cyano-6-(heptylamino)pyrazine-2-carboxamide were active against Mycobacterium kansasii and Mycobacterium avium, which are unsusceptible to PZA. Basic structure-activity relationships are presented. Only weak antifungal and no antibacterial activity was detected.     

Emerging from the ice-fungal communities are diverse and dynamic in earliest soil developmental stages of a receding glacier

We used amplicon sequencing and isolation of fungi from in-growth mesh bags to identify active fungi in three earliest stages of soil development (SSD) at a glacier forefield (0–3, 9–14, 18–25 years after retreat of glacial ice). Soil organic matter and nutrient concentrations were extremely low, but the fungal diversity was high [220 operational taxonomic units (OTUs)/138 cultivated OTUs]. A clear successional trend was observed along SSDs, and species richness increased with time. Distinct changes in fungal community composition occurred with the advent of vascular plants. Fungal communities of recently deglaciated soil are most distinctive and rather similar to communities typical for cryoconite or ice. This indicates melting water as an important inoculum for native soil. Moreover, distinct seasonal differences were detected in fungal communities. Some fungal taxa, especially of the class Microbotryomycetes, showed a clear preference for winter and early SSD. Our results provide insight into new facets regarding the ecology of fungal taxa, for example, by showing that many fungal taxa might have an alternative, saprobial lifestyle in snow-covered, as supposed for a few biotrophic plant pathogens of class Pucciniomycetes. The isolated fungi include a high proportion of unknown species, which can be formally described and used for experimental approaches.