Isolation and properties of a soluble sialidase from the culture fluid of Chinese hamster ovary cells

A Soluble sialidase that can degrade recombinant glycoproteinsexpressed in Chinese hamster ovary (CHO) cells has been isolatedand purified to near homogeneity from the cell culture fluidof this host. Purification of     

Actin and spectrin-like (Mr= 260–240 000) proteins in gregarines

In Gregarina blaberae a M_r = 47 000 and a M_r = 260–240 000 doublet polypeptides reacted in immunoblotting: i) with a polyclonal monospecific rabbit antibody to frog muscular actin, a monoclonal anti-actin antibody against chicken gizzard; and ii) with polyclonal and monoclonal antibodies to human erythrocyte β-spectrin, respectively. The M_r = 47 000 actin-like protein is associated with the ghost and a contractille cytoplasmic extract. The presence of an actin-like protein in Gregarina and Lecudina and its cellular distribution in the cortex indicated that the gliding movement might involve an actin-myosin system in contrast to previous studies. Immunofluorescence showed clear differences between the anterior part of Gregarina and Lecudina which illustrated the high cell polarity of these protozoa. The M_r = 260–240 000 doublet was detected in SDS-PAGE from G. blaberae trophozoite ghosts but not in the cytoplasmic extracts or in extracts from sexual stages, indicating that the presence of these spectrin-like proteins is stage-dependent. Visualization of the M_r = 260–240 000 by immunofluorescence showed clear species differences, with rings arranged perpendicular to the longitudinal narrow folds of G. blaberae, with longitudinal lines underlying the folds of L. pellucida and with lines separating the large folds of Selenidium pendula. The cellular distribution is consistent with a stabilizer function of the spectrin-like proteins in the scaffolding of the cortex of gregarines according to the high diversity of the cell-shape and the cell motility systems in gregarines. The presence of spectrin-like proteins in protozoa and particularly in parasites from primitive arthropods indicated that ancestral spectrin genes could the M_r = 260–240 000 form.     

ANTAGONISTIC PLEIOTROPY: AN INTERSPECIFIC DROSOPHILA COMPARISON

Wild-type flies of 12 Drosophila species and semispecies were examined to determine whether correlation patterns between early- and late-life fitness characters predicted for individuals within a population by the antagonistic-pleiotropy hypothesis are reflected in comparisons of related species and semispecies that are known to differ in lifespan. Our goal was to determine whether the hypothesis is relevant to the evolution of life-history differences beyond the population level. Two fitness traits, egg production and percentage mating success, were observed at three ages: onset of reproductive age, one week later, and one month later. Age-dependent patterns of these traits do not consistently conform to predictions of the hypothesis. Species or semispecies that show reproductive vitality early in life need not be short-lived, and long lifespan need not be accompanied by a cost in early reproductive vitality, as measured by mating success and egg production. The two fitness traits can show different age-dependent patterns in the same species or semispecies. Potential explanations for the frequent inconsistency of the data with predictions of the hypothesis are discussed. Results support the idea that the hypothesis is only relevant to the evolution of life-history differences among individuals in the same breeding population confronted by the same environmental constraints.     

UNDERGROUND MORPHOLOGY AND HABITAT RELATIONSHIPS OF THREE PAIRS OF FOREST HERBS

To evaluate the ecological importance of differences in underground morphology, ten individuals per species were excavated for three species pairs in a coniferous forest in the Cascade Mountains of Oregon. The two species of each pair had similar aboveground morphologies, divergent underground morphologies, and different geographical ranges and habitat relationships. Erythronium montanum and Clintonia uniflora have one or two elliptic leaves per ramet but E. montanum has a short, segmented rhizome and only one ramet per genet, whereas C. uniflora spreads vegetatively via long rhizomes. Streptopus roseus and Smilacina stellata have similar, determinant aerial shoots and spread by long rhizomes, but S. stellata has a dimorphic root and rhizome system that allows it to occupy a wider range of habitats. Rubus pedatus and Rubus lasiococcus both spread via stolons, but R. lasiococcus has deeper roots and can occupy drier habitats than R. pedatus. The differences in underground morphology within the species pairs are consistent with the species’ geographical ranges and habitats occupied, and may be causal in determining distribution patterns.     

Expression of {beta}-galactoside {alpha}2,6-sialyltransferase does not alter the susceptibility of human colon cancer cells to NK-mediated cell lysis

The extent of processing of N-linked oligosaccharides and thesialylation of the target cell membranes has been positivelycorrelated with resistance to lysis mediated by NK cells, buta conclusive evidence has never been reached. Colon cancer tissuesexpress an increased activity of ß-ga-lactoside     

Reproductive pattern,perinatal mortality,and sex preference in rural Tamil Nadu,south India: community based,cross sectional study.

OBJECTIVES: To study reproductive pattern and perinatal mortality in rural Tamil Nadu, South India. DESIGN: Community based, cross sectional questionnaire study of 30 randomly selected areas served by health subcentres. SETTING: Rural parts of Salem District, Tamil Nadu, South India. SUBJECTS: 1321 women and their offspring delivered in the 6 months before the interview. MAIN OUTCOME MEASURES: Number of pregnancies, pregnancy outcome, spacing of pregnancies, sex of offspring, perinatal and neonatal mortality rates. RESULTS: 41% of the women (535) were primiparous; 7 women (0.5%) were grand multiparous (> 6 births). The women had a mean age of 22 years and a mean of 2.3 pregnancies and 1.8 live children. The sex ratio at birth of the index children was 107 boys per 100 girls. The stillbirth rate was 13.5/1000 births, the neonatal mortality rate was 35.3/1000, and the perinatal mortality rate was 42.0/1000. Girls had an excess neonatal mortality (rate ratio 3.42%; 95% confidence interval 1.68 to 6.98; this was most pronounced among girls born to multiparous women with no living sons (rate ratio 15.48 (2.04 to 177.73) v 1.87 (0.63 to 5.58) in multiparous women with at least one son alive). CONCLUSIONS: In this rural part of Tamil Nadu, women had a controlled reproductive pattern. The excess neonatal mortality among girls constitutes about one third of the perinatal mortality rate. It seems to be linked to a preference for sons and should therefore be addressed through a holistic societal approach rather than through specific healthcare measures.     

Multiple redundant circadian oscillators within the isolated avian pineal gland

Summary The avian pineal gland contains a circadian pacemaker that oscillates in vitro. Using a flow-through culture system it is possible to measure melatonin production from very small subsections of an individual gland. We have used this technique to attempt to localize the oscillators in the pineal. Progressive tissue reduction did not affect the rhythmicity of cultured pineals. Multiple pieces (up to eight) from a single pineal all were capable of circadian oscillation — establishing directly that a pineal gland contains at least eight oscillators. All pineal pieces were responsive to light, and single light pulses shifted the phase of the melatonin rhythm. Because pieces equivalent to less than one per cent of the whole gland were rhythmic and because the capacity for oscillation was distributed throughout the gland, an individual pineal appears to be composed of a population of circadian oscillators.     

Gas-chromatographic resolution of the enantiomers of 3-(3,4-dihydroxyphenyl)alanine and its α-methyl analog

Methylation of (R,S)-DOPA with diazomethane gave the trimethyl derivative in which the phenolic hydroxy groups and the carboxy group were methylated. N-Methylated side products were also formed. N-Acylation of the racemic trimethyl derivative with (S)-α-methoxy-α-trifluoromethylphenylacetyl chloride gave two diastereomeric amides which were resolved by gas chromatography, the diastereomer derived from (S)-(−)-DOPA cluting first. The procedure was also applied to α-methyl-DOPA.