Correlation of HLA-Cw*06 allele frequency with some clinical features of psoriasis vulgaris in the population of northern Poland

Psoriasis is a common skin disease with a genetic background and significant human leukocyte antigen (HLA) associations. HLA-Cw6 is the most frequently described association, particularly with psoriasis of the early onset type. Few studies of its correlation with various psoriasis clinical phenotypes and severity of the disease have been published so far; none in the Polish population. In this study 78 patients with psoriasis vulgaris were evaluated clinically and subdivided according to the age of onset and the type of psoriasis. A system of disease severity evaluation was applied to each patient. All patients and the control group (70 unrelated persons) were typed for HLA-Cw*06. The results show that Cw*06 allele frequency was higher in psoriatics than in the control group. Our investigation confirms that the Cw*06 allele is positively associated with psoriasis vulgaris of the early onset type, with a positive family history and its more severe form.     

Heavy metal ions inhibition of jack bean urease: potential for rapid contaminant probing

The kinetics of heavy metal ions inhibition of jack bean urease was studied by progress curve analysis in a reaction system without enzyme-inhibitor preincubation. The inhibition was found to be biphasic with an initial, small inhibitory phase changing over the time course of 5-10 min into a final linear steady state with a lower velocity. This time-dependent pattern was best described by mechanism B of slow-binding inhibition, involving the rapid formation of an EI complex that subsequently undergoes slow conversion to a more stable EI* complex. The kinetic parameters of the process, the inhibition constants Ki and Ki* and the forward k5 and reverse k6 rate constants for the conversion, were evaluated from the reaction progress curves by nonlinear regression treatment. Based on the values of the overall inhibition constant Ki*, the heavy metal ions were found to inhibit urease in the following decreasing order: Hg2+ > Cu2+ > Zn2+ > Cd2+ > Ni2+ > Pb2+ > Co2+ > Fe3+ > As3+. With the Ki* values as low as 1.9 nM for Hg2+ and 7.1 nM for Cu2+, 100-1000 times lower than those of the other ions, urease may be utilized as a bioindicator of the trace levels of these ions in environmental monitoring, bioprocess control or pharmaceutical analysis.     

Anatomical and histological changes in the alimentary tract of migrating blackcaps (Sylvia atricapilla): a comparison among fed, fasted, food-restricted, and refed birds

During northward migration, blackcaps that arrive to refuel at stopover sites in Israel's Negev Desert have reduced masses of organs that are important in food digestion and assimilation. We tested several predictions from the general hypothesis that smaller organs of digestion (small intestine and pancreas) and nutrient assimilation (liver) bring about a lower capacity to consume food and that the organs must be restored before blackcaps can feed and digest at a high rate. We used a fasting protocol to create a group of blackcaps with reduced intestine and liver mass (reduced by 45% and 36%, respectively) compared with controls fed ad lib. Because most of the small intestine's biochemical digestive capacity reside in enterocytes found on villi, we predicted and found that reduced intestinal mass in fasted blackcaps related mainly to changes in enterocytes rather than other cells and tissues such as nonabsorptive crypt cells or underlying muscle. Because migrating blackcaps that stop over to feed begin to increase in body mass only 2 d after arrival, we predicted and found a similar recovery period in blackcaps that were first fasted but then refed--the organ mass, structure, function, and ability to consume food was restored after 2 d of feeding. Another group of food-restricted blackcaps (fed at one-third ad lib. level) lost similar amounts of body mass as fasted blackcaps but had much greater capacity to consume food than fasted blackcaps, and so we predicted that they would exhibit little or no reduction in alimentary organs relative to controls fed ad lib. A surprising result was that, as in fasted blackcaps, in food-restricted blackcaps, the decreases in masses of small intestine, liver, and pancreas were proportionally greater than the decreases in body mass or in masses of nonalimentary organs (heart, pectoralis). Food restriction, like fasting, caused a decrease in amount of intestinal mucosa and an alteration in the phenotype of enterocytes. These results are thus not consistent with the general hypothesis, and although they can be rationalized by assuming that blackcaps fed ad lib. have excess digestive capacity, it may also be that the physiological process or processes limiting very high feeding rate lie elsewhere than in the digestive system.     

Toxicity of microcystin from cyanobacteria growing in a source of drinking water

Microcystin-LR (MC-LR) is a cyanobacterial heptapeptide that presents acute and chronic hazards to animal and human health. The morphological changes in mitochondria are the primary effect induced by MC-LR leading to cell death. We investigated the toxicity of cyanobacterial microcystin-containing extract (CEM) on the respiratory complex of mammalian mitochondria from Bos taurus. Cyanobacterial blooms of Microcystis aeruginosa were harvested from Sulejow Reservoir, a source of drinking water in central Poland. The concentration of microcystin-LR (MC-LR(CEM)) in CEM extract was determined by high-performance liquid chromatography (HPLC). Commercially available microcystin-LR (Sigma) was used as a standard (MC-LR(S)); both standard and CEM extract were incubated with mitochondria in different doses and time of exposure. MC-RL(CEM) at 1 nM, maximal acceptable dose of microcystin (WHO) in drinking water, provoked activation of cytochrome c oxidase complex in mitochondria. We suggest that it might be considered as a defensive signal of mitochondria against low concentration of a toxic compound. In contrast 1 iM MC-RL(CME) inhibited the activity of mitochondrial oxidase complex much stronger than the same concentration of standard MC-RL(S) (58% vs. 87% of control activity, P<0.05), and this may cause a similar effect to long-term consumption of water. In conclusion, we affirm that CEM extract is highly toxic, and mitochondria could be used as an indicator of this toxicity in vivo, especially during long-term consumption of water from reservoirs where microcystin is produced.     

Pythons metabolize prey to fuel the response to feeding

We investigated the energy source fuelling the post-feeding metabolic upregulation (specific dynamic action, SDA) in pythons (Python regius). Our goal was to distinguish between two alternatives: (i) snakes fuel SDA by metabolizing energy depots from their tissues; or (ii) snakes fuel SDA by metabolizing their prey. To characterize the postprandial response of pythons we used transcutaneous ultrasonography to measure organ-size changes and respirometry to record oxygen consumption. To discriminate unequivocally between the two hypotheses, we enriched mice (= prey) with the stable isotope of carbon (13C). For two weeks after feeding we quantified the CO2 exhaled by pythons and determined its isotopic 13C/12C signature. Ultrasonography and respirometry showed typical postprandial responses in pythons. After feeding, the isotope ratio of the exhaled breath changed rapidly to values that characterized enriched mouse tissue, followed by a very slow change towards less enriched values over a period of two weeks after feeding. We conclude that pythons metabolize their prey to fuel SDA. The slowly declining delta13C values indicate that less enriched tissues (bone, cartilage and collagen) from the mouse become available after several days of digestion.     

Induction of globin mRNA expression by interleukin-3 in a stem cell factor-dependent SV-40 T-antigen-immortalized multipotent hematopoietic cell line

Erythropoiesis requires the stepwise action on immature progenitors of several growth factors, including stem cell factor (SCF), interleukin 3 (IL-3), and erythropoietin (Epo). Epo is required to sustain proliferation and survival of committed progenitors and might further modulate the level of expression of several erythroid genes, including globin genes. Here we report a new SCF-dependent immortalized mouse progenitor cell line (GATA-1 ts SCF) that can also grow in either Epo or IL-3 as the sole growth factor. When grown in SCF, these cells show an "open" chromatin structure of the beta-globin LCR, but do not significantly express globin. However, Epo or IL-3 induce globin expression and are required for its maintainance. This effect of IL-3 is unexpected as IL-3 was previously reported either to be unable to induce hemoglobinization, or even to antagonize it. This suggests that GATA-1 ts SCF cells may have progressed to a stage in which globin genes are already poised for expression and only require signal(s) that can be elicited by either Epo or IL-3. Through the use of inhibitors, we suggest that p38 may be one of the molecules modulating induction and maintenance of globin expression.     

Bone microstructure and developmental plasticity in birds and other dinosaurs

Patterns of bone microstructure have frequently been used to deduce dynamics and processes of growth in extant and fossil tetrapods. Often, the various types of primary bone tissue have been associated with different bone deposition rates and more recently such deductions have extended to patterns observed in dinosaur bone microstructure. These previous studies are challenged by the findings of the current research, which integrates an experimental neontological approach and a paleontological comparison. We use tetracycline labeling and morphometry to study the variability of bone deposition rates in Japanese quail (Coturnix japonica) growing under different experimental conditions. We compare resulting patterns in bone microstructure with those found in fossil birds and other dinosaurs. We found that a single type of primary bone varies significantly in rates of growth in response to environmental conditions. Ranging between 10-50 microm per day, rates of growth overlap with the full range of bone deposition rates that were previously associated with different patterns of bone histology. Bone formation rate was significantly affected by environmental/experimental conditions, skeletal element, and age. In the quail, the experimental conditions did not result in formation of lines of arrested growth (LAGs). Because of the observed variation of bone deposition rates in response to variation in environmental conditions, we conclude that bone deposition rates measured in extant birds cannot simply be extrapolated to their fossil relatives. Additionally, we observe the variable incidence of LAGs and annuli among several dinosaur species, including fossil birds, extant sauropsids, as well as nonmammalian synapsids, and some extant mammals. This suggests that the ancestral condition of the response of bone to environmental conditions was variable. We propose that such developmental plasticity in modern birds may be reduced in association with the shortened developmental time during the later evolution of the ornithurine birds.     

Persistence of Mhc heterozygosity in homozygous clonal killifish,Rivulus marmoratus: implications for the origin of hermaphroditism

The mangrove killifish Rivulus marmoratus, a neotropical fish in the order Cyprinodontiformes, is the only known obligatorily selfing, synchronous hermaphroditic vertebrate. To shed light on its population structure and the origin of hermaphroditism, major histocompatibility complex (Mhc) class I genes of the killifish from seven different localities in Florida, Belize, and the Bahamas were cloned and sequenced. Thirteen loci and their alleles were identified and classified into eight groups. The loci apparently arose approximately 20 million years ago (MYA) by gene duplications from a single common progenitor in the ancestors of R. marmoratus and its closest relatives. Distinct loci were found to be restricted to different populations and different individuals in the same population. Up to 44% of the fish were heterozygotes at Mhc loci, as compared to near homozygosity at non-Mhc loci. Large genetic distances between some of the Mhc alleles revealed the presence of ancestral allelic lineages. Computer simulation designed to explain these findings indicated that selfing is incomplete in R. marmoratus populations, that Mhc allelic lineages must have diverged before the onset of selfing, and that the hermaphroditism arose in a population containing multiple ancestral Mhc lineages. A model is proposed in which hermaphroditism arose stage-wise by mutations, each of which spread through the entire population and was fixed independently in the emerging clones.