Immunohistochemical demonstration of carbonic anhydrase

Summary Rabbits were immunized using human erythroxyte carbonic anhydrase B (HCA B) purified. by the modified methods of Armstrong et al. (1966) and Bernstein and Schraer (1972). The globulin fraction was isolated by ammonium sulphate precipitation. The anti-HCA B globulin was specific, when judged using the double diffusion technique of Ouchterlony and immunoelectrophoresis. No cross reaction with human erythrocyte carbonic anhydrase C was found, but cross reactions with erythrocyte carbonic anhydrase from rat, mouse and guinea pig were observed. Fluorescein isothiocyanate conjugated goat anti-rabbit globulin was used for the localization of HCA B in tissue sections and erythrocytes on slides.     

Intracellular resistance correlates with initial stage of frost hardening in willow (Salix viminalis)

Distributed model parameters of shoots of five clones of willow ( Salix viminalis ) were examined with electrical impedance analysis at the end of the growing season and with cold acclimation. The parameters were compared with regard to frost hardiness, linoleic (18:2) and linolenic (18:3) fatty acids, unsaturation/saturation ratio of fatty acids and dry weight content. The intracellular resistance (r_i) correlated best with changes in frost hardiness. The value of r_i rose from 1–2 Ω m in non-hardened to about 12 Ω m in hardened samples. In the initial stages of frost hardening, a linear relationship was found between r_i and frost hardiness and levels of 18:2 fatty acid, and an inverse relationship between r_i and levels of 18:3 fatty acid. The unsaturation/saturation ratio of fatty acids rose fairly rapidly in the initial stage of hardening. The dry weight content increased stepwise during the experimental period, and less steadily than r_i. In addition, equivalent circuit parameters changed in the prehardening phase, and were probably connected with cell differentiation and lignification. Frost hardiness by the visual method and by extracellular resistance, determined after controlled freezing tests, correlated well in the initial stages of hardening until about − 10°C but deviated upon further hardening.     

In vitro experimental studies of sialyl Lewis x and sialyl Lewis a on endothelial and carcinoma cells: crucial glycans on selectin ligands

Extravasation from the blood of malignant tumour cells that form metastasis and leukocytes that go into tissues require contact between selectins and their sialyl Lewis x and sialyl Lewis a (sLex and sLea respectively) decorated ligands. Endothelial cells have been shown to express sLex epitopes in lymph nodes and at sites of inflammation, and this is crucial for the selectin-dependent leukocyte traffic. Besides the ability to synthesize sLex on sialylated N-acetyllactosamine via the action of α(1,3)fucosyltransferase(s), endothelial cells can also degrade sLex to Lewis x through the action of α(2,3)sialidase(s). In addition, several epithelial tumors possess the machinery to synthesize sLex, which facilitates their adhesion to endothelial E- and P-selectin. This revised version was published online in November 2006 with corrections to the Cover Date.     

Kinetic analysis of deoxyribonuclease I cleavages in the nucleosome core: evidence for a DNA superhelix

The location of the DNase I-sensitive sites along the DNA of the 140 base-pair nucleosome core have been determined by using DNase I to digest nucleosome cores labelled at either the 5′ or 3′ ends of their DNA. The frequency of enzyme attack at each site has also been determined from a kinetic analysis of this data. It is found that most of the sites spaced 10n bases apart (where n is an integer) on a single strand of the DNA are attacked, but at widely differing rates.It is proposed that the pattern of relative rates of attack reflects the common protection or exposure of sites on the two turns of a DNA super helix which has about 80 base-pairs per turn and can be correlated with X-ray crystallographic studies. Furthermore, the asymmetric distribution of frequencies of attack from one end of a strand to the other can be interpreted in terms of a left-handed super helix.     

Alcohol detoxification accelerated by oxygenated drinking water.

The liver eliminates ethanol through several oxygen dependent processes. Since the liver receives most of its blood flow through the portal vein, it should be possible to increase its oxygen tension by augmenting the oxygen saturation of the portal vein. We therefore studied elimination of ethanol administered intravenously to three monkeys who received strongly oxygenated drinks at 20 to 30 minute intervals during the whole experiment. From these drinks dissolved oxygen was presumably released in the stomach and upper intestine and arrived to the liver along the portal vein. As a consequence of this treatment the elimination rate of ethanol increased 60 % on the average. The increase was significant on the level of p < 0.02. The production of acetaldehyde also increased but less significantly. Measurements of oxygen tensions in the portal blood of two anaesthetized dogs indicated 7 and 8 % increases lasting for 10 and 15 minutes after infusion of oxygenated water into the stomach.     

TESS3: fast inference of spatial population structure and genome scans for selection

Geography and landscape are important determinants of genetic variation in natural populations, and several ancestry estimation methods have been proposed to investigate population structure using genetic and geographic data simultaneously. Those approaches are often based on computer‐intensive stochastic simulations and do not scale with the dimensions of the data sets generated by high‐throughput sequencing technologies. There is a growing demand for faster algorithms able to analyse genomewide patterns of population genetic variation in their geographic context. In this study, we present TESS3 , a major update of the spatial ancestry estimation program TESS . By combining matrix factorization and spatial statistical methods, TESS3 provides estimates of ancestry coefficients with accuracy comparable to TESS and with run‐times much faster than the Bayesian version. In addition, the TESS3 program can be used to perform genome scans for selection, and separate adaptive from nonadaptive genetic variation using ancestral allele frequency differentiation tests. The main features of TESS3 are illustrated using simulated data and analysing genomic data from European lines of the plant species Arabidopsis thaliana.