Preliminary crystallographic data for cross-linked (lysine7-lysine41)-ribonuclease A

A cross-linked derivative of ribonuclease A, N^ε,N^ε′-(2,4-dinitrophenylene-1,5)-(lysine⁷-lysine⁴¹)-RNase A, has been crystallized by dialysis against 30% ($\text{v}\text{v}$) ethanol/water mixtures buffered at high pH. Single crystals belong to the orthorhombic space group P2₁2₁2₁, $\text{a = 37.2}\text{A}\text{?}\text{, b = 41.2}\text{A}\text{?}\text{, b = 41.2}\text{A}\text{?}$, with one molecule in the Crystallographic asymmetric unit.     

Effects of Nitrate Application on Amaranthus powellii Wats. : I. Changes in Photosynthesis, Growth Rates, and Leaf Area

Physiological effects of different nitrate applications were studied using the C₄ plant, Amaranthus powellii Wats. Plants were grown in a controlled environment chamber and watered daily with nutrient solutions containing 45, 10, 5, or 1 millimolar nitrate. Chloride and sulfate were used to keep the cation and phosphate concentrations constant. Total leaf nitrogen concentration, chlorophyll concentration, specific leaf mass, leaf area, relative growth rate, relative leaf growth rate, unit leaf rate (increase of dry mass per unit leaf area per day), net photosynthetic rate, and incident quantum yield decreased with decreasing nitrate concentration. The per cent decrease of unit leaf rate was similar to the decrease of light-saturated net photosynthetic rate; however, the decrease in relative growth rate was less than that of unit leaf rate because leaf area ratio (leaf area per unit dry mass) increased with decreasing nitrate concentration. Essential mineral concentrations per unit leaf area were about equal among all treatments. Leaf expansion, determined by stomatal density, decreased except for the 1 millimolar treatment which showed relatively more cell expansion but less cell division. Decreased nitrate application was correlated with higher osmotic potentials and lower pressure potentials (determined by pressure-volume curves), whereas leaf water potentials were equal among treatments. Even though total leaf area and shoot mass decreased with decreasing applied nitrate, the increase of the leaf area ratio may be related to selection for the highest possible growth rate.     

Effects of temperature at constant air dew point on leaf carboxylation efficiency and CO2 compensation point of different leaf types

The effect of temperature on photosynthesis at constant water-vapor pressure in the air was investigated using two sclerophyll species, Arbutus unedo and Quercus suber, and one mesophytic species, Spinacia oleracea. Photosynthesis and transpiration were measured over a range of temperatures, 20–39° C. The external concentration of CO₂ was varied from 340 bar to near CO₂ compensation. The initial slope (carboxylation efficiency, CE) of the photosynthetic response to intercellular CO₂ concentration, the CO₂ compensation point (), and the extrapolated rate of CO₂ released into CO₂-free air (R _i) were calculated. At an external CO₂ concentration of 320–340 bar CO₂, photosynthesis decreased with temperature in all species. The effect of temperature on was similar in all species. While CE in S. oleracea changed little with temperature, CE decreased by 50% in Q. suber as temperature increased from 25 to 34° C. Arbutus unedo also exhibited a decrease in CE at higher temperatures but not as marked as Q. suber. The absolut value of R _i increased with temperature in S. oleracea, while changing little or decreasing in the sclerophylls. Variations in and R _i of the sclerophyll species are not consistent with greater increase of respiration with temperature in the light in these species compared with S. oleracea.Abbreviations and symbols A net photosynthetic rate - C and C _i CO₂ concentration in the air and in the intercellular airspace of the leaf, respectively - CE carboxylation efficiency - E transpiration rate - R _i CO₂ release into CO₂-free air estimated from extrapolation to 0 bar CO₂ - T _i leaf temerature - VPD difference in water-vapor pressure between mesophyll and air - CO₂ compensation point     

Thermography as a predictive tool for laser treatment of port-wine stains

The argon laser, which has been proven both useful and safe for port-wine stain therapy, interacts with the hemoglobin of the vessels. In a percentage of cases, this treatment is still inefficient, and there is a lack of correlation between these bad results and clinical or histologic criteria. Thermography, which explores the vascularization of the port-wine stain, leads us to consider port-wine stains from a physical point of view. This very simple test shows no correlation with the clinical parameters of port-wine stain but is closely related to the results obtained with laser therapy. It seems to be a good criterion to estimate the argon laser treatment prognosis.     

A physical and genetic map of the IncFI plasmid ColV2-K94

A restriction enzyme map of the IncFI plasmid ColV2-K94 was generated using EcoRI, BamHI, HindIII, and XhoI; the genetic features of this element were then mapped from previous heteroduplex studies.     

Demonstration of a beta-casomorphin immunoreactive material in the plasma of newborn calves after milk intake

Blood was collected from newborn calves before and after their first milk intake after birth; extracts of plasma were assayed by radioimmunoassay for the presence of beta-casomorphin-7 immunoreactive materials. No beta-casomorphin immunoreactivity was found in samples collected before milk ingestion; however, in samples collected after milk ingestion a beta-casomorphin-7 immunoreactive material was detected. Chromatographic characterization showed that this material was not identical with beta-casomorphin-7 but might rather represent a precursor thereof. The material proved resistant to enzymatic attack during a 30-min incubation period at 37 degrees C in the plasma of newborn calves, whereas beta-casomorphin-7 was degraded under these conditions. A physiological significance of beta-casomorphin-7 eventually cleaved from such a precursor material at any site in the newborn mammal is suggested.     

The regulatory chain in the p36-kd substrate complex of viral tyrosine-specific protein kinases is related in sequence to the S-100 protein of glial cells.

The major cytoplasmic target of various tyrosine-specific protein kinases is a 36-kd protein (p36). This protein can exist as a monomer or as a complex with a small subunit which seems to have a regulatory function. Amino acid sequence analysis of the small subunit from porcine intestine documents a unique polypeptide of 95 residues with a calculated mol. wt. close to 11 kd (p11). Since an immunologically related subunit of the same electrophoretic mobility is also found in the corresponding complex of chicken intestine p11 is well conserved across species. Unexpectedly, the sequence of p11 shows a high homology with the glia-specific protein S-100 whose biological function is not known. Although both proteins are dimers of rather small polypeptides we have not been able to detect in our preparations of p11 the moderate Ca2+ binding known for S-100. Certain implications of this sequence relation are discussed.     

Antifungal therapy of dermatophytosis in guinea pigs and congenitally athymic rats

Guinea pigs and athymic nude (RNU/RNU) rats were used to assess the efficacy of three orally administered antifungal agents — Tolciclate, Tolnaftate, and Ketoconazole — against Trichophyton mentagrophytes dermatophytosis. All three antifungal agents inhibited the test strain of T. mentagrophytes in vitro. Antifungal agents were tested in intervention (oral therapy started 5 days after challenge) or prophylaxis (oral therapy started 5 days before challenge) protocols. Oral treatment of dermatophytosis on guinea pig skin demonstrated that Tolciclate and Tolnaftate alleviated clinical symptoms and shortened the duration of the dermatophytosis, in comparison to nontreated controls. Assessment of antifungal efficacy in the guinea pig model was time consuming (30–35 days) and variability in the duration and severity of clinical symptoms on guinea pig skin was common.Oral therapy of chronically infected athymic rats demonstrated that Tolciclate, Tolnaftate, and Ketoconazole were effective antifungal agents in vivo. Obvious improvement in clinical symptoms of dermatophytosis (i.e. less erythema and fewer lesions) was evident with all three antifungal agents within 10 days of starting oral therapy. By day 20, athymic rats that were treated with either Tolciclate or Ketoconazole showed marked clinical improvement of the chronic dermatophytosis.Chronically infected athymic rats, which lack thymus matured T-cells, are a promising new model to evaluate the efficacy of antifungal agents by culture, histology, and visual observations of clinical symptoms.     

Isolation of sulfited oligosaccharides from glycoproteins treated with alkaline sulfite

The oligosaccharide products resulting from treatment of mucin-type glycoproteins with alkali in the presence of the sulfite anion have been investigated. Treatment of fetuin and of tryptic glycopeptides from the human erythrocyte with this reagent resulted in the release of sulfited oligosaccharides identified as N-acetylsulfohexosamine (HexNAcSO3), alpha-NeuAc-(2----6)-HexNAcSO3, and alpha-NeuAc-(2----3)-Gal-(1----3 or 4)-[GlcNAc-(1----6)]-HexNAcSO3. In addition, 2.7 moles of sialic acid were released per mole of alpha-NeuAc-(2----6)-HexNAcSO3 from fetuin. The sulfohexosamine moiety is formed via unsaturated intermediates from a 3-O-substituted 2-acetamido-2-deoxy-D-galactosyl residue at the carbohydrate-peptide linkage site when this residue is not substituted at O-4 by another sugar residue. A reaction mechanism accounting for the release of the sulfited oligosaccharides from a 3-O- and 6-O-substituted hexosamine is proposed in which the oligosaccharide branch attached to O-6 is obtained as a specific fragment terminating in sulfohexosamine.