Level of polysomes in cells of Escherichia coli treated with sublethal doses of aminoglycosides

Polysome level was measured in Escherichia coli cells grown in the presence of sublethal doses of four different aminoglycosides which all induce mistranslation: streptomycin, neomycin, kanamycin and gentamycin. No significant variation was noticed as referred to the level of polysomes in normally growing cells. This observation indicates that the erroneous incorporation of amino acids into polypeptide chains does not necessarily result in the release of ribosomes from messenger RNA molecules.     

Effect of gentamycin on insulin release and45Ca net uptake by isolated islets

Summary In isolated islets, gentamycin reduced both the⁴⁵Ca net uptake and insulin release induced by glucose, but failed to inhibit the insulin secretion provoked by the combination of Ba²⁺ and theophylline. This indicates that the inhibitory effect of gentamycin is due to a reduction of Ca²⁺ entry into B-cells instead of to a harmful effect upon the integrity of the effector system, responsible for the extrusion of the insulin containing granules.Supported by a Grant (No. 79/1872) from the São Paulo State Research Foundation (FAPESP), Brazil.     

Aminoglycoside antibiotics: old drugs and new therapeutic approaches

Aminoglycoside antibiotics kill bacteria by binding to the ribosomal decoding site and reducing fidelity of protein synthesis. Since the discovery of these natural products over 50 years ago, aminoglycosides have provided a mainstay of antibacterial therapy of serious Gram-negative infections. In recent years, aminoglycosides have become important tools to study molecular recognition of ribonucleic acid (RNA). In an ingenious exploitation of the aminoglycosides’ mechanism of action, it has been speculated that drug-induced readthrough of premature stop codons in mutated messenger RNAs might be used to treat patients suffering from certain heritable genetic disorders. Received 23 January 2007; received after revision 25 February 2007; accepted 29 March 2007     

Synergistic effect of rabbit specific antiserum and amikacin on the treatment of mice with lethal infection due toKlebsiella pneumoniae

Summary A combination of rabbit specific antiserum and amikacin showed a synergistic effect on the treatment of mice with lethal infections due to a strain ofKlebsiella pneumoniae.     

Action de la castration partielle ou totale sur la croissance et le fonctionnement de l'appareil génital chez le planorbeBiomphalaria glabrata (gastéropode pulmoné)

Summary Total castration increases the weight, delays oviposition and reduces the functioning of the genital organs but partial gonadectomy has no effect. After partial castration, the ovotestis does not regenerate. Partial or total castration has no effect on the wet and dry weight of the genital tracts.     

Effects of L-lysine administration on certain aspects of ascorbic acid metabolism in weanling rats

Summary L-lysine administration to male weanling rats at a dose of 110.4 mg (25% LD₅₀) per 100 g body weight per day for 15 days reduced the liver total ascorbic acid level. The biosynthesis as well as the degradation of L-ascorbic acid was diminished under these conditions. The fall in liver total ascorbic acid level after L-lysine administration was ascribed to its reduced synthesis.Acknowledgment. The authors are thankful to the Council of Scientific and Industrial Research, India, for providing Junior Research Fellowships to Miss J. Basu and Miss K. Sen Gupta.     

Plants as a direct source of fuel

Summary Euphorbia lathyris, a plant which has been proposed as an energy farm candidate yields a total of 35% of its dry weight as simple organic extractables. Chemical analyses of the extracts show that 5% of the dry weight is a mixture of reduced terpenoids, in the form of triterpenoids, and 20% of the dry weight is simple sugars in the form of hexoses. The terpenoids can be converted to a gasoline-like substance and the sugars can be fermented to alcohol. Based on a biomass yield of about 25 dry tons ha^–1 year^–1, the total energy that can be obtained from this plant in the form of liquid fuels is 48 MJ ha^–1 year^–1, 26 MJ in the form of hydrocarbons and 22 MJ in the form of ethanol. A conceptual process study for the large scale recovery ofEuphorbia lathyris products indicates that this crop is a net energy producer. Several lines of investigation have been started to increase the hydrocarbon yield of this plant. Tissue cultures ofE. lathyris have been established and will be used for selection, with the aim of regenerating a superior plant. Biochemical studies have been initiated to elucidate regulation of terpenoid metabolism. Future plans include eventual genetic engineering to select the most desirable plant for hydrocarbon production.This work was supported by the Assistant Secretary for Conservation and Solar Energy, Office of Solar Energy, Solar Applications for Industry Division of the US Department of Energy under Contract No. W-7405-ENG-48.     

Activité gonadotrope d'un extrait d'urines de femmes en ménopause

Summary An extract from pooled postmenopausal urine has been investigated for its gonadotrophic activity. Dose-response curves have been constructed for its total gonadotrophic activity (stimulation of estrogen secretion as reflected by the uterine weight increase in immature mice) and for its ICSH activity (stimulation of androgen secretion as reflected by the ventral prostate weight increase in hypophysectomised immature rats). In hypophysectomised immature rats, the extract produced repair of the interstitial cells of the testes and complete spermatogenesis. It contains, therefore, FSH as well as ICSH activity in comparable amounts, a fact which opens up interesting therapeutic possibilities.     

Elemental sulphur (S<Subscript>8</Subscript>) in higher plants — biogenic or anthropogenic origin

In the course of investigating lipophilic air pollutants in the epicuticular wax ofPinus sylvestris L. needles, elemental sulphur, S₈, was found in all samples. An investigation was conducted to determined the origin of this substance. No correlation between the level of S₈ in the needles and human activities in the sampling area could be found, contrary to what would have been expected of an anthropogenic compound. The internal lipids ofP. sylvestris as well as the epicuticular wax of historical herbarium material and seedlings grown in clean, filtered air, and the epicuticular wax of several other species, both gymnosperms and angiosperms, also contained S₈. Quantitation of S₈ inP. sylvestris gave levels of 7.2±2.9 μg/g wax, 3.8±1.9 μg/g internal lipid and 0.43±0.17 μg/g total needle dry weight. Almost 0.1% of the total sulphur in pine needles is S₈, and approximately half of the total S₈ is found in the wax. The results suggest that S₈ is endogenous in many higher plants. A function for S₈ as part of an antifungal defence system is possible.     

The use of 5-fluorocytosine and ketoconazole in the culture of the erythrocytic stages ofPlasmodium falciparum and some tumor cell lines

Summary In vitro culture systems are often contaminated by bacteria and fungi. It is therefore often necessary to supplement culture media with agents such as penicillin/streptomycin, gentamycin or amphotericin B. The latter cannot be used in the in vitro culture of erythrocytic stages ofP. falciparum, and thus anti-fungal agents have not been regularly used in this system. We describe the prophylactic use of 5-fluorocytosine (5-FC) and ketoconazole (KTZ) in tissue cultures at concentrations up to 300 and 10 g/ml respectively which have no effect on the growth ofP. falciparum (FCR-3 strain). A melanoma cell line (C32) and a line of uterine carcinoma (C41) were also unaffected by similar concentrations of 5-FC and KTZ. When dissolved in complete culture medium (RPMI 1640) with 10% human plasma, the minimum inhibitory concentration of 5-FC for a susceptible strain ofCandida remained below 2 g/ml. These experiments suggest that 5-FC (at 50 g/ml) alone or in combination with KTZ (at 1 g/ml) is a useful addition to the armamentarium of antimicrobials available to the tissue culture biologist for a variety of cell culture systems.     

Spectrum of Aeromonas and Plesiomonas infections in patients with cancer and AIDS

The spectrum of infection with Aeromonas and Plesiomonas included gastroenteritis, bacteremia, biliary tract infection, perirectal infection, and disseminated disease. Most patients (86%) with bacteremia were neutropenic (less than 500 PMN/mm3). Colonization of stools and sputum also occurred. Therapy with aminoglycosides, beta-lactams, trimethoprim/sulfamethoxazole, and the newer quinolones was effective in patients with AIDS and cancer.     

Die zentralnervöse Rangstufe des Blauwals (Sibbaldus musculus Linnaeus)

Summary Macroscopic anatomical investigations on the brain of the Blue Whale (Sibbaldus musculus Linnaeus, total brain weight without dura: 6500 g), show that this species of cetacea has a degree of cerebralization between that of the primitive Southern Right Whale (Eubalaena australis Desmoulins) and that of the Humpback Whale (Megaptera novaeangliae Borowski). Of the Balaenopteridae examined to date, the Blue Whale has the lowest cerebralization.

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Durchgeführt mit Unterstützung des Schweizerischen Nationalfonds zur Förderung der wissenschaftlichen Forschung (Gesuch Nr. 3883/1966).     

Subcellular distribution and binding of heavy metals in the untreated liver of the squid; comparison with data from the livers of cadmium and silver-exposed rats

In natural squid liver, about 30% of the total Cd present was found in the cytosolic fraction. A large portion of this Cd was bound to high molecular weight species (mol. wt greater than 70,000). In contrast to Cd, about 60% of the total Ag occurred in the cytosolic fraction; Ag was bound mainly to low molecular weight species (mol. wt less than 20,000).     

Das Körpergewicht der Ratte als Parameter zur Bestimmung der Höhenadaptation

Summary Rats, kept in cages, show a transitory weight loss after exposure to high altitude, due to a reduced food intake. The measurement of the extent and the duration of the weight loss before the weight prior to exposure is regained can be used for the determination of the adaptability. The results of measurements at 3,450 m show that the adaptability decreases with age.

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Die Mittel zur Durchführung der Arbeit wurden von der Max-Planck-Gesellschaft zur Förderung der Wissenschaften, Deutschland, zur Verfügung gestellt.     

Oyster mushroom (Pleurotus ostreatus) reduces the activity of 3-hydroxy-3-methylglutaryl CoA reductase in rat liver microsomes

The effect of dried oyster mushroom (Pleurotus ostreatus) on cholesterol (C) content in serum, in lipoproteins and in liver, and on the activity of 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase in liver microsomes, was studied in male rats (strain Wistar, initial body weight 75 g) fed on low-cholesterol (9 mg/100 g) and high-cholesterol (0.3%) diets. Addition of 5% oyster mushroom to both diets reduced significantly the C-content in serum (by 30%), in very-low- and low-density lipoproteins (in a 11 ratio to the decrease of total serum C) and in liver (by 50%), as well as the activity of HMG-CoA reductase (by more than 30%).     

Alterations in the phospholipid composition ofNocardia polychromogenes during growth

Summary The major phospholipid classes ofNocardia polychromogenes were quantitated at different stages of the growth cycle. Significant differences were observed both in the total lipid phosphorus per g (dry weight) of cells, and in the relative percentages of individual phospholipids. The total amount of lipid-phosphorus increased throughout the growth cycle. Cardiolipin and phosphoinositides contents increased with significant decrease in phosphatidyl ethanolamine and unknown phospholipids.Acknowledgments. This investigation was supported in part by a grant from the Indian Council of Medical Research. Technical assistance of Mr Adarsh Kumar is acknowledged.     

Similarities between metallothionein and low molecular weight testicular cadmium-binding protein

Summary The incorporation of³⁵S-cysteine and³H-glutamic acid was studied in mouse hepatic and renal metallothionein and in testicular cadmium-binding protein of similar molecular weight. Preferential incorporation of³⁵S-cysteine over³H-glutamic acid was observed not only in hepatic and renal metallothionein, but also in testicular cadmium-binding protein. When the antigenic reactivity of these proteins was compared, all three proteins reacted with the metallothionein antibody. These similarities suggest that the low molecular weight testicular cadmium-binding protein is apparently metallothionein.     

Experimenteller Beitrag zur Frage der Klärfaktoraktivierung

Summary After intravenous injection of a³⁵S-labelled heparinoid (N-formyl-chitosan-polysulfuric acid ester) into rabbits, a highly purified clearing factor preparation was obtained from the blood plasma. The heparinoid content of this preparation is approximately 40 times higher, weight for weight, than that of the other plasma proteins.      

Molekül-Massenspektrographie von Naturstoffen. Steroide

Summary The molecular weight of various steroids (sterols, steroidal sapogenins, and alkaloids) as well as the molecular weight distribution in complex mixtures of similar steroids, has been exactly determined by application of molecule mass spectrography. In this technique, negatively-charged (p – 1) ions are formed, usually without further fragmentation. The advantages and new possibilities of this method are discussed.

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I. Mitteilung.     

Increased ALA dehydratase activity and spleen weight in lead-intoxicated rats. A consequence of increased blood cell destruction

Summary Lead was given in the diet (1%) to rats from birth and at different times the animals were studied for delta amino levulinic acid dehydratase (ALAD) activity, spleen weight,⁵⁹Fe incorporation in erythrocytes and⁵¹Cr-labeled erythrocytes survival. The increased ALAD and spleen weight found after lead treatment is explained as a consequence of a shortened survival, which results in a younger age of circulating erythrocytes with higher ALAD activity.Supported by Contract No. 140-76-12 ENV. B. of the E. C. Environmental Research Program.