Glucose and mannitol diffusion in human dura mater

An in vitro experimental study of the control of the human dura mater optical properties at administration of aqueous solutions of glucose and mannitol has been presented. The significant increase of the dura mater optical transmittance under action of immersion liquids has been demonstrated. Diffusion coefficients of glucose and mannitol in the human dura mater tissue at 20 degrees C have been estimated as (1.63 +/- 0.29) x 10(-6)cm(2)/s and as (1.31 +/- 0.41) x 10(-6) cm(2)/s, respectively. Experiments show that administration of immersion liquids allows for the effective control of tissue optical characteristics that make dura mater more transparent, thereby increasing the ability of light penetration through the tissue.     

Maternal effects on offspring depend on female mating pattern and offspring environment in yellow dung flies

Abstract Direct costs and benefits to females of multiple mating have been shown to have large effects on female fecundity and longevity in several species. However, with the exception of studies examining genetic benefits of polyandry, little attention has been paid to the possible effects on offspring of multiple mating by females. We propose that nongenetic effects of maternal matings on offspring fitness are best viewed in the same context as other maternal phenotype effects on offspring that are well known even in species lacking parental care. Hence, matings can exert effects on offspring in the same way as other maternal environment variables, and are likely to interact with such effects. We have conducted a study using yellow dung flies ( Scathophaga stercoraria ), in which we independently manipulated female mating rate, number of mates and maternal thermal environment and measured subsequent fecundity, hatching success, and offspring life-history traits. To distinguish between direct effects of matings and potential genetic benefits of polyandry we split broods and reared offspring at three different temperature regimes. This allowed us to demonstrate that although we could not detect any simple benefits or costs to matings, there are effects of maternal environment on offspring and these effects interact with female mating regime affecting offspring fitness. Such interactions between female phenotype and the costs and benefits of matings have potentially broad implications for understanding female behavior.     

Steady-state assemblages of phytoplankton in four temperate lakes (NE U.S.A.)

For four temperate lakes (Northeast U.S.A.) we identify periods of persistent phytoplankton assemblages and investigate the ecological conditions that correlate to these persistent assemblages. Periods of persistent assemblages, here considered as steady-state phases, were defined according to equilibrium criteria (two or three coexisting species, contributing to 80% of the standing biomass, for at least 2 weeks) defined by Sommer et al. (1993, Hydrobiologia 249: 1–7). For all four lakes, samples were taken weekly during the ice-free season and phytoplankton attributes (biomass, assemblages, diversity, species richness, change rates) and abiotic variables (temperature, I^* – as light mean in the mixing zone – z_mix, and nutrients) were analysed. Chodikee (CH), an eutrophic and rapidly flushed lake, did not show any persistent phase. The remaining three lakes showed single steady-state phases that occurred at varying times during the ice-free season. Steady-state phases occurred during early stratification in late spring in the stably stratified oligotrophic Mohonk Lake (MO), in the late summer stratification in the meso-eutrophic Stissing Lake (ST), and during spring mixing in Wononscopomuc Lake (WO). MO showed a 3-week period with dominance of F assemblage (Botryococcus braunii, Willea wilhelmii and Eutetramorus planctonicus), characteristic for clear epilimnia, tolerant to low nutrient and sensitive to high turbidity. For three weeks, ST had a stable assemblage with dominance of Lo(Woronichinia sp.), common assemblage in summer epilimnion of mesotrophic lakes and sensitive to prolonged or deep mixing; and P, assemblage able to live in eutrophic epilimnia with mild light and sensitive to stratification and silica depletion. In contrast, the mesotrophic Wononscopomuc Lake (WO) showed persistent assemblages during a 4-week period of spring circulation, when a dinoflagellate (Lo) was co-dominant with Nitzschia acicularis (C). The latter species is characteristic for mesotrophic lakes, tolerant to low light and sensitive to stratification and silica depletion. Both Lo and P assemblages, among seven others, had before been quoted, in literature, as dominant in maturing stages. We could not find consistent statistical differences between the periods classified as steady-state and non-steady-state. However, the data demonstrated that prolonged period of both mixing and stratification can maintain dominant assemblages. Although, historically sensed as opposite mechanisms, both mixing and stratification, if persistent, were observed maintaining dominant assemblages because both scenarios are characterized by environmental constancy.     

Immunotoxicological effects of dermal application of scum of waste crankcase oil in mice

The scum of waste crankcase oil (SWCO) forms due to weathering of waste crankcase oil, deposited on the surface of water bodies. It is known to attach to the feathers of aquatic birds and cause toxicity to the eggs of nestling birds. The water bodies contaminated with SWCO can also be a source of toxicity to the human beings and animals entering such bodies. Since SWCO used in the present study had an appreciable content of heavy metals like Zn, Pb, Cd, Mn, Cr and Ni, the present investigation was undertaken to study a probable effect on immune system of mice. Animals treated with SWCO at a dose of 0.5, 1.0, 2.0, or 4.0 g/kg body weight for 28 days, had no effect on the weight gain of vital organs. A depressing effect was observed on the cell population of spleen and thymus. The number of primary antibody (IgM) producing cells was significantly depressed in spleen. The IgM antibody titer of serum, reduction of NBT dye by peritoneal exudat cells and mounting of delayed hypersensitivity response were not affected. In view of above immunotoxic effects of SWCO, the waste crankcase oil should be carefully disposed of, away from water bodies.     

Toxicity of argemone oil: Effect on hsp70expression and tissue damage in transgenic Drosophila melanogaster(hsp70-lacZ) Bg 9

The effect of argemone oil on hsp70expression and tissue damage was investigated by studying β-galactosidase activity, Western blotting and hybridization, and trypan blue staining in the larval tissues of transgenic Drosophila melanogaster(hsp70-lacZ)Bg ⁹. Different concentrations of argemone oil were mixed with food and third-instar larvae were allowed to feed on them for different time intervals (2, 4, 24, and 48 h). Argemone oil was found to induce hsp70even in the lowest concentration of the adulterant while maximum tissue damage was observed in the higher two treatment groups. Malpighian tubules and midgut tissue reflected maximum damage as evidenced by both high β-galactosidase activity and trypan blue staining in these tissues. A prior temperature shock treatment to the larvae was enough to protect the larvae from argemone oil-induced tissue damage as evidenced by little or no trypan blue staining. The present study suggests the cytotoxic potential of argemone oil and further strengthens the evidence for the use of hsp70as a biomarker in risk assessment. This revised version was published online in August 2006 with corrections to the Cover Date.     

Structure of a new 2-deoxy-2-[(R)-3-hydroxybutyramido]-D-glucose-containing O-specific polysaccharide from the lipopolysaccharide of Citrobacter gillenii PCM 1542

The O-specific polysaccharide of Citrobacter gillenii PCM 1542 from serotype O-12a,12 b is composed of one residue each of D-glucose, D-GlcNAc, 2-deoxy-2-[(R)-3-hydroxybutyramido]-D-glucose (D-GlcNAcyl) and two GalNAc residues. On the basis of sugar and methylation analyses of the intact and Smith degraded polysaccharides, along with 1D and 2D 1H and 13C NMR spectroscopy, the following structure of the branched pentasaccharide repeating unit of the O-specific polysaccharide was established:This structure differs significantly from that of the O-specific polysaccharide of C. gillenii PCM 1544 from the same serotype O-12a,12 b, which has been established earlier (Kübler-Kielz.shtsls;b, J. et al. Carbohydr. Res. 2001, 331, 331-336). Serological studies confirmed that the two O-antigens are not related and suggested that strains PCM 1542 and 1544 should be classified into different O-serogroups.     

Subcloning,expression, purification,and characterization of recombinant human leptin-binding domain

A subdomain of the human leptin receptor encoding part of the extracellular domain (amino acids 428 to 635) was subcloned, expressed in a prokaryotic host, and purified to homogeneity, as evidenced by SDS-PAGE, with over 95% monomeric protein. The purified leptin-binding domain (LBD) exhibited the predicted beta structure, was capable of binding human, ovine, and chicken leptins, and formed a stable 1:1 complex with all mammalian leptins. The binding kinetics, assayed by surface plasmon resonance methodology, showed respective k(on) and k(off) values (mean +/- S.E.) of 1.20 +/- 0.23 x 10(-5) mol(-1) s(-1) and 1.85 +/- 0.30 x 10(-3) s(-1) and a K(d) value of 1.54 x 10(-8) m. Similar results were achieved with conventional binding experiments. LBD blocked leptin-induced, but not interleukin-3-induced, proliferation of BAF/3 cells stably transfected with the long form of human leptin receptor. The modeled LBD structure and the known three-dimensional structure of human leptin were used to construct a model of 1:1 LBD.human leptin complex. Two main residues, Phe-500, located in loop L3, and Tyr-441, located in L1, are suggested to contribute to leptin binding.