Helminth infections in faecal samples of wolves Canis lupus L. from the western Beskidy Mountains in southern Poland

Eighty-nine samples of grey wolf (Canis lupus L.) faeces were collected between 2002 and 2004 from two areas in the western Beskidy Mts (south Poland). Helminth eggs were observed in 56.2% of faeces examined. These included: Alaria alata (2.2%), taeniid eggs (11.2%), Toxocara canis (5.6%), Toxascaris leonina (1.1%), Eucoleus aerophilus (14.6%), Ancylostoma caninum (12.3%), Uncinaria stenocephala (37%) and unidentified roundworm eggs of the family Strongyloididae (1.1%). Eucoleus aerophilus is recorded for the first time from Poland. The results are compared with the helminth fauna of other wolf populations in Europe.     

Amino-caprolactam derivatives as gamma-secretase inhibitors

A series of amino-caprolactam sulfonamides were developed from a screening hit. Compounds with good in vitro and in vivo gamma-secretase activity are reported.     

Putative type IV secretion genes in Bacillus anthracis

Although the physiology of Bacillus anthracis, the causative agent of anthrax, has been studied extensively, we still do not know how toxins are dispatched from the bacterial cell. Here, by means of distant homology and genome context analyses, we identify genes encoding putative type IV secretion system-related elements on the B. anthracis plasmids pXO1 and pXO2 and in the chromosome. We argue that this type IV secretion system-like system could be responsible for anthrax toxin secretion, although we also discuss the possibilities of its involvement in the processes of sporulation, germination or conjugation.     

Crystal structure of RNase T, an exoribonuclease involved in tRNA maturation and end turnover

The 3' processing of most bacterial precursor tRNAs involves exonucleolytic trimming to yield a mature CCA end. This step is carried out by RNase T, a member of the large DEDD family of exonucleases. We report the crystal structures of RNase T from Escherichia coli and Pseudomonas aeruginosa, which show that this enzyme adopts an opposing dimeric arrangement, with the catalytic DEDD residues from one monomer closely juxtaposed with a large basic patch on the other monomer. This arrangement suggests that RNase T has to be dimeric for substrate specificity, and agrees very well with prior site-directed mutagenesis studies. The dimeric architecture of RNase T is very similar to the arrangement seen in oligoribonuclease, another bacterial DEDD family exoribonuclease. The catalytic residues in these two enzymes are organized very similarly to the catalytic domain of the third DEDD family exoribonuclease in E. coli, RNase D, which is monomeric.     

Cell surface properties as factors involved in Proteus vulgaris adhesion to stainless steel under starvation conditions

The purpose of these investigations was to evaluate the influence of limited nutrient availability in the culture medium on Proteus vulgaris biofilm formation on surfaces of stainless steel. The relationship between the P. vulgaris adhesion to the abiotic surfaces, the cellular ATP levels, cell surface hydrophobicity and changes in the profiles of extracellular proteins and lipopolysaccharides was examined. In all experimental variants the starvation conditions induced the bacterial cells to adhere to the surfaces of stainless steel. Higher ATP content and lower cell surface hydrophobicity of P. vulgaris cells was observed upon nutrient-limited conditions. Under starvation conditions a reduction in the levels of extracellular low molecular weight proteins was noticed. High molecular weight proteins formed the conditioning layer on stainless steel plates, making the bacteria adhesion process more favorable. The production of low molecular weight carbohydrates promoted more advanced stages of P. vulgaris biofilm formation process on the surfaces of stainless steel upon starvation.     

Pioglitazone induces de novo ceramide synthesis in the rat heart

Ceramide (CER) is an important mediator of lipotoxicity in the heart. It was found that Zucker diabetic fatty rats develop an age-dependent accumulation of myocardial CER leading to cardiomyocyte apoptosis. However, administration of peroxisome proliferator-activated receptor (PPAR) gamma agonist decreased the content of CER and prevented cardiomyocyte apoptosis [Zhou et al. Proc Natl Acad Sci USA 2000;97:1784-9]. These data suggest that PPARgamma activators affect myocardial CER metabolism. Therefore, the aim of our study was to examine the effects of pioglitazone, a selective PPARgamma agonist, on the content of CER and its metabolites and on the activity of key enzymes of CER metabolism in the heart. The experiments were conducted on rats fed either a standard chow (STD) or a high-fat diet (HFD) for 21 days. Each group was divided into two subgroups: control and treated with pioglitazone for 14 days. Surprisingly, administration of PPARgamma agonist significantly increased myocardial CER content in both STD and HFD rats. In the latter group an elevation in the amount of sphingomyelin was also observed. In STD rats pioglitazone treatment increased the activity of neutral sphingomyelinase and acid ceramidase. However, in HFD group the compound did not affect the activity of the aforementioned enzymes. Interestingly, the activity of serine palmitoyltransferase in both STD and HFD rats increased two-fold after pioglitazone treatment. We conclude that pioglitazone induced accumulation of CER in rat myocardium as a result of augmented CER synthesis de novo. However, in the STD group increased activity of neutral sphingomyelinase could also contributed to this effect.     

A practical method for overcoming the dormancy of <Emphasis Type="Italic">Taxus baccata</Emphasis> isolated embryos under <Emphasis Type="Italic">in vitro</Emphasis> conditions

Conditions for obtaining an efficient mass propagation procedure to overcome isolated Taxus baccata embryo dormancy were investigated. The protocol herein described was efficient for overcoming the dormancy of T. baccata isolated embryos under in vitro conditions, enabling the conservation and propagation of this species. T. baccata seeds were unable to germinate directly after collection under in vitro conditions. Very good sterility and germination was achieved by soaking seeds in distilled water at a low temperature (+4°C) at least for 48 h instead of leaching them for 7 d under running water, followed by maintaining isolated embryos on the Murashige and Skoog medium (MS) supplemented with 5 g l⁻¹ activated charcoal. That treatment allowed one to shorten the time of the experiment and gave almost 100% sterility. The best germination was observed in darkness, but to obtain worthy seedlings, it was necessary to place cultures in a 16-h photoperiod after a 2-wk incubation. There was no significant difference in germination between seeds collected from different populations of Southern Poland.     

Does the cellular labile iron pool participate in the oxidation of 2',7'-dichlorodihydrofluorescein?

The fluorogenic probe 2',7'-dichlorodihydrofluorescein diacetate (H₂DCF-DA) is widely used for the estimation of oxidative stress in cells. It is known that 2',7'-dichlorodihydrofluorescein (H₂DCF), product of intracellular hydrolysis of H₂DCF-DA, is oxidized to the fluorescent compound, DCF, mainly by hydrogen peroxide (H₂O₂) in the presence of catalysts. The present study was aimed at answering the question whether the labile iron pool (LIP) may contribute to the oxidation of H₂DCF in cellular systems. The membrane-permeable lipophilic iron chelator salicylaldehyde isonicotinoyl hydrazone (SIH) was found to inhibit oxidation of the probe by H₂O₂ dependent on ferrous ions but not by peroxidase or superoxide dismutase in defined in vitro systems. When applied to cells, the probe inhibited considerably oxidation of H₂DCF in V79 Chinese hamster fibroblasts and two murine lymphoma L5178Y(LY) sublines (LY-R, LY-S) differing in LIP level, the extent of inhibition being greater in the LY-R line of higher LIP level. These results demonstrate that LIP is a significant factor determining the rate of intracellular H₂DCF oxidation.     

On flower visitors and true pollinators: The case of protandrous Heracleum sphondylium L. (Apiaceae)

Hogweed (Heracleum sphondylium L.), a common European umbellifer, is very variable in terms of flower and inflorescence morphology. Its flowers are visited by numerous insects, yet little is known about the importance of the particular insect taxa. I observed umbels of two colour morphs (subspecies) of Heracleum sphondylium growing in NE Poland, which were visited by more than 108 insect species during two study seasons. Analysis of the insects' importance suggests that the most efficient pollinators are the medium-sized flies Eriozona syrphoides, and Lucilia spp. (Diptera). Bumblebees Bombus terrestris (Hymenoptera), beetles of genus Stenurella spp. and Dasytes spp. (Coleoptera) and flies Eristalis spp., Meliscaeva cinctella, Phaonia angelicae and Thricops nigrifrons also contribute to pollination of the studied plants, but their efficiency shows considerable seasonal variation. Although the dense umbels of the white flowered H. sphondylium subsp. sphondylium are generally more attractive for insect visitors than the loose yellowish inflorescences of H. sphondylium subsp. sibiricum, these taxa do not seem to attract different sets of the pollinators. For both subspecies, flowers in the staminate phase were visited significantly more often than those in the pistillate phase. Some flower visitors visited the staminate phase only, which suggests they may be parasites rather than pollinators.     

A comparison of the effectiveness, tolerability and safety of high and low carbohydrate diets in women with gestational diabetes

INTRODUCTION: Nutrition therapy is an integral part of the management of gestational diabetes mellitus (GDM). Most women with GDM are treated by nutritional management alone. The goal of our study was to compare low and high carbohydrate diets in their effectiveness, safety and tolerability in women with GDM. MATERIAL AND METHODS: The study group consisted of 30 Caucasian women newly diagnosed with GDM, with a mean age of 28.7 +/- 3.7 years and pregnancy duration of 29.2 +/- 5.4 weeks. The patients were randomised into two groups: those on a low and those on a high carbohydrate diet (45% vs. 65% respectively of energy supply coming from carbohydrates). The presence of urine ketones was controlled every day. After two weeks daily glucose profiles and compliance with the recommended diets were analysed. RESULTS: Glucose concentration before implementation of the diet regimen did not differ between groups. No changes in fasting blood glucose were noticed in the group that had followed a low carbohydrate diet, although a significant decrease in glucose concentration was observed after breakfast (102 +/- 16 vs. 94 +/- 11 mg/dl), lunch (105 +/- 12 vs. 99 +/- 9 mg/dl) and dinner (112 +/- 16 vs. 103 +/- 13 mg/dl) (p < 0.05). In the high carbohydrate diet group fasting and after-breakfast glucose concentration did not change. A significant decrease in glycaemia was noticed after lunch (106 +/- 15 vs. 96 +/- 7 mg/dl) and dinner (107 +/- 12 vs. 97 +/- 7 mg/dl) (p < 0.05). Ketonuria was not observed in either group. Obstetrical outcomes did not differ between groups. CONCLUSIONS: Both high and low carbohydrate diets are effective and safe. A diet with carbohydrate limitation should be recommended to women who experience the highest glycaemia levels after breakfast.