In vitro OKT3-induced mitogenesis in selenium-deficient patients on a diet for phenylketonuria

Patients with phenylketonuria (PKU) are frequently deficient in the essential trace element selenium (Se), because of their very low protein diet. Using two approaches to investigate T-cell response to proliferative signaling, viz, mitogenesis caused by the monoclonal antibody OKT3 and the plant lectin phytohaemagglutinin (PHA), we demonstrated significantly reduced responses to optimal concentrations of OKT3 in a group of PKU patients with reduced serum Se compared with a normal group (p = 0.0005) and with a group of PKU patients whose serum Se was normal (p = 0.0023). The response of the Se-deficient group to optimal levels of PHA did not differ from that of the normal controls or from that of Se-normal PKU patients. A dose-dependent relationship between serum Se levels and mitogenic response was evident for OKT3 (r = 0.34, p = 0.0154), but not for PHA (r = -0.02, p = 0.9086). We suggest that the reduced response to OKT3 mitogenesis in Se-deficient PKU patients is possibly the consequence of impaired Se-dependent metabolic activity, which affects mitogenic signaling via the T cell antigen receptor (TCR/CD3) complex.     

Stature variation in the British American Colonies: French and Indian War records, 1755-1763

Personnel records kept by military units of American colonials during the French and Indian War (1755-1763) are analyzed for relationships between environmental factors and stature. A robust American economy and direct access to high-quality food were apparently critical to tallness of this white American male sample. American-born men were taller at all ages than those who had migrated from Europe. January temperatures, rural versus urban birth, and ethnicity also showed stature relationships within the American-born group; thermal effects were by far the strongest of the non-nutritional factors.     

Dihydrotetrabenazine Binding and Monoamine Uptake in Mouse Brain Regions

The objective of the present study was to estimate extracellular pH (pHe) and intracellular pH (pHi) during near-complete forebrain ischemia in the rat, and to evaluate the relative importance of lactic acidosis and rise in tissue Pco2 (Ptco2) in causing pHe and pHi to fall. The animals, which were ventilated, normoxic, normocapnic, and normothermic, were subjected to 15 min of ischemia, either without or with 30-60 min of recirculation. Ptco2 was measured with a tissue electrode, pHe with a double-barrel liquid ion-exchanger microelectrode, changes in extracellular fluid (ECF) volume by impedance measurements, tissue CO2 content by a microdiffusion technique, and labile tissue metabolites by enzymatic fluorometric methods. Ischemia caused Ptco2 to rise to between 95 and 190 mm Hg (mean 149 mm Hg), and pHe to fall by 0.45-1.05 units (mean 0.70 units). During recovery, Ptco2 normalized within 5 min and pHe after 15-30 min. During ischemia, high-energy phosphates were depleted and tissue lactate content increased to 15 mumol X g-1. The total CO2 content (Tco2) was minimally or moderately reduced (normal, 11.9 mumol X g-1; range of ischemic values, 7.9-12.1 mumol X g-1), this range probably reflecting variable amounts of remaining blood flow. Impedance measurements demonstrated that ECF volume during ischemia was reduced to 55% of control, with gradual normalization during the first 15-30 min of recirculation. From values for Ptco2, Tco2, [HCO3-]e, and ECF volume, [HCO3-]i and pHi could be calculated. These values pertain to an idealized homogeneous intracellular compartment, and the methods used cannot detect whether different intracellular compartments diverge in their acid-base responses.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparative study of methods for the quantification of fungal spores at the leaf surfaces ofPopulus xeuramericana

Summary The removal of fungal spores, urediniospores ofMelampsora medusae and conidia ofPestalozzia sp., from the leaf surfaces ofPopulus xeuramericana (Dode) Guinier cv. I-488 was assessed using three cultural techniques conventionally employed in phylloplane studies. The method of removal and the original density of spore deposition, but not the interaction of these factors, were significant determinants of variability in spore removal. Irrespective of the original density of deposition, the leaf print method was the most, and the leaf washing technique the least, efficient means of spore removal from the leaf surface. Factors which could contribute to this difference in efficiency are discussed.     

Photoacoustic and fluorescence measurements of the chilling response and their relationship to carbon dioxide uptake in tomato plants

The response of tomato plants to various chilling treatments was studied using two approaches for the measurement of photosynthetic activity. One involved the use of a portable fluorometer for the measurement of in-vivo chlorophyll fluorescence, while the other employed a newly introduced photoacoustic system which allowed changes in oxygen evolution to be followed in a leaf disc. A strong correlation was found between results obtained by each system and those obtained by a conventional open gas-exchange system for the determination of CO₂ uptake. Both systems of measurements could readily distinguish between the effects of chilling in the dark (at 3° C for 18 h) and chilling at high photon flux density (2000 mol m^-2 s^-1 for 5h at 5° C). Chilling in the dark had practically no effect on the quantum yield of oxygen evolution, chlorophyll fluorescence or CO₂ uptake, while chilling at excessively high photon flux density resulted in a sharp reduction (50–70%) in the quantum yields obtained. The results support the view that photosystem II cannot be the primary site of damage by chilling in the dark, although it is significantly affected by chilling at high light intensity.Abbreviations DCMU 3-(3,4-dichlorophenyl)-1,1-dimethylurea - PA photoacoustic - PFD photon flux density - PSII photosystem II     

Triterpenes from Periandra dulcis roots

Three oleanane triterpenes were isolated from the roots of Periandra dulcis,and identified as 3β-hydroxy-25-al-olean-18-en-30-oic acid (periandric acid I), 3β-hydroxy-25-al-olean-12-en-30-oic acid (periandric acid II) and 3-oxo-25-hydroxy-olean-12-en-30-oic acid. The former two compounds (periandric acids I and II) were identical with the aglycones obtained by hydrolysis of periandrin I and II, respectively and the latter one was a new triterpene.     

On the Recovery of [3H]Noradrenaline from Different Metabolic Compartments of Rat Brain with Respect to the Role of Catechol-O-Methyltransferase

Abstract: Rats were treated with reserpine, desmethylimipramine, or carrier, either alone or in combination with tropolone. Either 10 min (t₁) or 1 h (t₂) after intraventricular injection of [³H]noradrenaline, they were decapitated. The total ³H activity and the recovery of [³H]noradrenaline were determined in tissue extracts from various brain regions. Maximum total ³H activity was measured at t₁ in all tropolone-treated rats; the mean sum of these results served as an estimate of the initial tissue concentration of [³H]noradrenaline. At t₁, 40–50% of the sum of [³H]noradrenaline and its metabolites was recovered unchanged in normal rats; reserpine and DMI reduced the recovery to 18–27%. In all groups, the decline of [³H]noradrenaline was retarded after t₁. Inhibition of catechol-O-methyltransferase by tropolone caused consistently elevated [³H]noradrenaline levels, but did not affect the metabolic rate after t₁ when compared with similarly pretreated, but tropolone-free rats. Thus, if catechol-O-methyltransferase was inhibited during the injection of [³H]noradrenaline, a higher percentage of the amine had been taken up into spaces with a slow noradrenaline turnover. The maximum increase was seen when the neuronal uptake, was inhibited by desmethylimipramine. This supported the hypothesis that an additional extraneuronal space exists, in addition to the known intraneuronal and extraneuronal compartments, which has a slow noradrenaline turnover. The tropolone effect on the noradrenaline recovery possibly shows that there might be a saturable “methylating system,” similar to that described for the periphery, in which catechol-O-methyltransferase is linked to the extraneuronal uptake₂. By affecting the access of noradrenaline to non-neuronal cells it might influence the rate of noradrenaline elimination from the intercellular space.     

海枣曲霉β-半乳糖苷酶的提纯与性质

 通过过聚乙二醇6000-磷酸钾缓冲液双相分离、Sephadex G-100凝胶过滤、DEAE-Sephadex A-50离子交换层析、羟基磷灰石层析及SephadexG-100凝胶过滤等提纯步骤,从海枣曲霉(Aspergillus phoenicis)麦麸培养物抽提液中提纯得到凝胶电泳均一的β-半乳糖苷酶。该酶的最适pH为3.5—4.0,最适温度为60℃(反应15分钟),在pH5.0—8.5之间及60℃以下稳定。在65℃和70℃保温时失活50％的时间分别为27和2分钟。用SDS凝胶电泳法和梯度凝胶电泳法分别测得该酶的分子量为115,000和118,000。薄层凝胶等电聚焦法测得其等电点为pH4.6。     

In vitro response of leaf tissues from Lolium multiflorum — a comparison with leaf segment position,leaf age and in vivo mitotic activity

Summary Immature gramineous leaves provide a convenient system for comparing the response of cells in culture with their state of differentiation. Callusing frequency is compared with leaf segment position, leaf age and in vivo mitotic activity in Lolium multiflorum. (1) In a succession of one millimeter sections from the immature leaf base, callus was formed from the first and second sections but not the third or subsequent sections. The frequency of those explants callusing decreased with distance from the base of the leaf and with leaf age (or leaf extension growth). (2) In vivo, the proportion of cells in mitosis declined from around 10–14% at the base of young leaves to zero at 5 mm from the base and beyond. Mitotic activity also declined in leaves as they aged, and dividing cells were not observed in leaves 30 days from initiation or older. (3) A high frequency of callus formation was associated with a high mitotic index in the explant. But for corresponding mitotic indices, cells further away from the leaf base were less responsive in culture. (4) It is proposed that cells are becoming differentiated even in highly meristematically active regions of the leaf and concomitantly losing their ability to respond in culture.     

Effects of external NaCl on the growth of Atriplex amnicola and the ion relations and carbohydrate status of the leaves

Abstract Atriplex amnicola, was grown in nutrient solution cultures with concentrations of NaCl up to 750 mol m^?3. The growth optimum was at 25–50 mol m^?3 NaCl and growth was 10–15% of that value at 750 mol m^?3 NaCl. Sodium chloride at 200 mol m^?3 and higher reduced the rate of leaf extension and increased the time taken for a leaf to reach its maximal length. Concentrations of Na⁺, K⁺ and Mg²⁺ in leaves of different ages were investigated for plants grown at 25, 200 and 400 mol m^?3 NaCl. Although leaves of plants grown at 200 and 400 mol m^?3 NaCl had high Na⁺ concentrations at young developmental stages, much of this Na⁺ was located in the salt bladders. Leaves excluding bladders had low Na⁺ concentrations when young, but very high in Na⁺ when old. In contrast to Na⁺, K⁺ concentrations were similar in bladders and leaves excluding bladders. Concentrations of K⁺ were higher in the rapidly expanding than in the old leaves. At 400 mol m^?3 NaCl, the K⁺:Na⁺ ratios of the leaves excluding bladders were 0.4–0.6 and 0.1 for rapidly expanding and oldest leaves, respectively. The Na⁺ content in moles per leaf, excluding bladders, increased linearly with the age of the leaves; concurrent increases in succulence were closely correlated with the Na ⁺ concentration in the leaves excluding the bladders. Soluble sugars and starch in leaves, stems and buds were determined at dusk and dawn. There was a pronounced diurnal fluctation in concentrations of carbohydrates. During the night, most plant parts showed large decreases in starch and sugar. Concentrations of carbohydrates in most plant organs were similar for plants grown at 25 and 400 mol m^?3 NaCl. One notable exception was buds at dusk, where sugar and starch concentrations were 30–35% less in plants grown at 400 mol m^?3 NaCl than in plants grown at 25 mol m^?3 NaCl. The data indicate that the growth of A. amnicola at 400 mol m^?3 NaCl is not limited by the availability of photosynthate in the plant as a whole. However, there could have been a growth limitation due to inadequate organic solutes for osmotic regulation.