Subcellular distribution of enzymes involved in α-glucan utilization in Klebsiella pneumoniae

The double-isotopic labelling technique was used to identify comprehensively proteins involved in α-glucan catabolism in Klebsiella pneumoniae NCTC 9633. Cells were grown with either glycerol in the presence of ³H-leucine or with glycerol plus maltose in the presence of ¹⁴C-leucine. Each labelled culture was then fractionated into the main subcellular components, i.e. the cytoplasm, periplasm, cytoplasmic and outer membrane. Corresponding fractions derived from ³H-labelled and ¹⁴C-labelled cells were combined, and the proteins were analyzed by polyacrylamide gel electrophoresis under denaturing conditions. Gel slices were then counted for ³H- and ¹⁴C-radioactivity, a positive deviation from the standard ¹⁴C/³H ratio being evidence for the presence of a protein specifically induced by maltose in the culture medium. The protein pattern thus obtained was compared with the properties of proteins comprising a similar pathway for maltodextrin utilization in Escherichia coli K-12. Ample information which has been obtained mainly by genetic analysis is available about maltodextrin-utilizing enzymes in E. coli K-12.

1. Cytoplasm. Neither amylomaltase nor maltodextrin phosphorylase, well-known soluble enzymes, were identifiable by the double-labelling technique, presumably because these enzymes constitute only a very minor portion of all soluble proteins in the cytoplasm.
2. Periplasm. A prominent protein with a mass of 43000 daltons (43 kD) was found similar to the maltose-binding protein of E. coli K-12 (44 kD).
3. Cytoplasmic membrane. At least 2 proteins with a mass between 40 and 50 kD were detected, minor proteins were seen at ≈ 15 and ≈ 20 kD. One or 2 of the proteins may function as a permease catalyzing the active transport of maltodextrins.
4. Outer membrane. The major protein had a mass of 55 kD, other proteins were found with ≈ 18, ≈48, and ≈140 kD. The major protein may have the same function as the maltodextrin pore protein in E. coli K-12 (55 kD), because K. pneumoniae could grow on 10 μM maltose at practically the same rate as on 10 mM maltose. The 140 kD protein is pullulanase.

     

Effects of isoniazid (INH) on the oogenesis of mice

Summary Mutagenic damages in female germ, cells of mice have been tested with the dominant, lethal assay and the cytogenetic analysis of unfertilized M II-oocytes. Concluding one can say that from the experimental data presented here do not show any mutagenic effect of INH on oogenesis of different strains of mice can be stated.     

Ion gradient and photoreceptor sensitivity

Summary In superposition eyes of moths (Deilephila elpenor, Manduca sexta) and a neuropteran (Ascalaphus macaronius) receptor excitation and adaptation depend on the limited store of available ion charges in the extra-cellular space.Na⁺ is the main charge carrier necessary for excitation. Receptor mass responses (measured by extracellular electrodes) can, however, be elicited also after complete removal of Na⁺ from the extra-ommatidial space. Responses are also obtained when Na⁺ is partially replaced by Ca⁺⁺ or Mg⁺⁺. These results suggest that the extra-ommatidial space is separated from the intra-ommatidial (rhabdomeric) extra-cellular space. Ion flow between these spaces is slow. The ion exchange during illumination probably takes place over the rhabdomeric part of the photoreceptor membrane.The Na⁺ concentration in the rhabdomeric extracellular space is about 150 mM, as shown by flame photometry. This result supports the assumption that this space is the common Na⁺ store for the three receptor types (UV, green, violet).Positive (optic lobe positive) DC polarization of the retina causes a reduction in the amplitude of the mass responses to light. After cessation of the polarization the amplitude increases with a time constant similar to that after strong illumination. Negative polarization accelerates the rate of increase in amplitude during dark adaptation, while positive polarization retards the increase. These results suggest that one important factor determining the time course of sensitivity increase during dark adaptation is the reestablishment of the Na⁺ gradient over the rhabdomeric membrane.There is a strong electric coupling between the three receptor types in the ommatidium, since all receptors share the same limited intra-ommatidial extra-cellular ion store. Strong illumination of one receptor reduces the ion gradient (extra- to intracellular) also for the other receptors (not absorbing the light). Thereby the sensitivity of the non-illuminated receptors is also reduced. The electric coupling probably improves the wavelength discrimination by the receptors, by keeping almost constant the relative sensitivity of all three receptor types during shortlasting strong selective adaptation of one or two receptor types.The time course of the resistance change over the receptor membrane (measured extra-cellularly) during and after illumination, suggests that during illumination the Na⁺ influx is reduced, and that the ion gradient over the receptor membrane is at least partially re-established already during the illumination.We are grateful to Dr. A.H. Baumhover (United States Department of Agriculture, Agricultural Research Service, Oxford, North Carolina 27565, USA) for supplying theManduca pupae. The work was supported by the Deutsche Forschungsgemeinschaft, SFB 114 and Rezeptorphysiologie; and by Karolinska Institutets Fonder.     

Besondere Haarstrukturen der Soricidae (Mammalia,Insectivora) und ihre taxonomische Deutung

Zusammenfassung Die vorliegende Untersuchung befaßt sich mit besonderen Haarfeinstrukturen der Soricidae, wobei geklärt werden soll, ob dem H-förmigen Haarquerschnitt-Profil eine taxonomische Bedeutung zukommt. Wir überprüften deshalb die betreffenden Haarstrukturen mit Hilfe des REM in 8 Gattungen.Das besondere Haarprofil, das auf das Terminalsegment der Grannenhaare beschränkt ist, findet sich bei folgenden Gattungen:Sorex, Neomys, Blarina undCryptotis, alles Vertreter der Subfamilie Soricinae. Sämtliche untersuchten Vertreter der Subfamilie Crocidurinae, d.h.Crocidura, Praesorex, Suncus undSylvisorex weisen ein einfaches Haarprofil auf.Das H-Profil wird als Synapomorphie der Soricinae angesehen und charakterisiert diese als monophyletische Gruppe. Die haarmorphologischen Kriterien ergänzen somit die osteologischen Kriterien von Repenning (1967) und sprechen für die Beibehaltung der von vielen Autoren abgelehnten Subfamilien.

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Special hair structures in Soricidae (Mammalia, Insectivora) and their taxonomic interpretation

Summary The following study should clear up the structures of the H-shaped profile found in the hairs of some shrews and show if it has a taxonomic signification. Therefore we studied the concerned hair structures by scanning electron microscopy in 8 genera.The special hair-shape, which is confined to the terminal segment of guard hairs, is found in the species of the following genera:Sorex, Neomys, Blarina andCryptotis, all members of the subfamily Soricinae. All the examined members of the subfamily Crocidurinae, i.e.Crocidura, Praesorex, Suncus andSylvisorex show a simple hair shape.The H-shaped hair characterizes the Soricinae as a monophyletic unity. Yet, the morphological criteria of hair complete the osteological criteria of Repenning (1967) an plead for the validitiy of the often refuted subfamilies.

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Mit Unterstützung des Schweizerischen Nationalfonds zur Förderung der wissenschaftlichen Forschung (Nr. 3.515.71, 3.821.72, 3.413-0.74)

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Unser Dank gilt Herrn Prof. N. Schönenberger, Herrn Prof.R. Krstic und Frau C. Regamey, die uns bei der histologischen Präparation behilflich waren, insbesondere auch Herrn Dr. T. Jalanti, der uns in die REM-Technik einführte. Kostbares Material wurde uns von Frau A. Geraets (Bonn), Herrn Prof. U. Rahm (Basel) und Herrn Dr. V. Aellen (Genf) zur Verfügung gestellt; auch ihnen sei hierfür herzlich gedankt.     

Alchemilla austriaca,spec. nova,(Rosaceae) — eine neue Art aus den Ostalpen

Alchemilla austriaca is a new species which belongs to the group ofA. demissa, A. frigens, A. longana, A. longiuscula, A. semisecta, andA. sinuata. The holotype specimen as well as leaf and flower details are illustrated (Figs. 1–3). A complete character analysis is given, differences and similarities of allied species are presented in two tables, and the position of the group within the genus is discussed.A. austriaca so far is known only from the Austrian Alps and mainly from the central ranges (distribution map: Fig. 4). Its wet subalpine and alpine habitats are characterized by species lists.

     

Fine structure of dense-cored vesicles in glomus cells of rat carotid body after fixation with permanganate or glutaraldehyde

Summary Glomus (Type I) cells of the carotid body of adult rats were studied electron microscopically after fixation with potassium permanganate or with glutaraldehyde and osmium tetroxide. Two permanganate fixation methods (using Krebs-Ringer-glucose, pH 7.0, or acetate buffer, pH 5.0) were compared. Numerous dense-cored vesicles were observed only in about one tenth of the glomus cells when neutral permanganate was used for fixation, although all glomus cells showed such vesicles after fixation with glutaraldehyde and osmium tetroxide. Numerous vesicles with a dense core were observed in about one third of the cells after fixation with acid potassium permanganate. With this fixation, small dense-cored vesicles similar to those in adrenergic nerve terminals were occasionally seen in the cytoplasm of glomus cells. It is tentatively concluded that the amine-storing vesicles of the carotid body are different from those in the small intensely fluorescent (SIF) cells and those in adrenergic nerve terminals.     

Serum Glutathione Peroxidase Activity and Blood Selenium in Pigs

Blood serum glutathione peroxidase activity and blood selenium concentration were measured in blood samples from pigs subjected to experimentally induced selenium deficiency and dietary selenium supplementation on graded levels. A highly significant correlation between blood selenium and serum GSH-Px activity in pigs, especially in selenium deficient pigs, was demonstrated. There was also a strong relationship between blood selenium concentration and serum GSH-Px activity in pigs receiving dietary selenium at graded levels. Serum GSH-Px activity exhibited an excellent close-response relationship to dietary selenium. Linear regression analysis showed that the increased serum GSH-Px activity was a function of the dietary selenium concentration. The fitness of serum in monitoring slight changes of the selenium status of pigs with help of the estimation of GSH-Px activity was discussed. The measurement of serum GSH-Px activity seems to provide a useful and rapid means for defining selenium requirements and for identifying selenium deficiency in growing pigs.     

Combined Therapeutic Effect of Dietary Selenium and Vitamin Ε on Manifested Vesd Syndrome in Weaned Pigs

By using a therapeutic dietary supplementation in pigs, which had developed the vitamin Ε and selenium deficiency (VESD) syndrome, the same amounts of α-tocopheryl acetate and selenium were found to be effective as under prophylactic conditions. The experiment thus supported the conclusions that the addition of 5 mg DL-α-tocopheryl acetate/kg and 135 μg selenium/kg to a diet, which contained only traces of vitamin Ε and selenium, represents a level of minimal requirement. Glutathione peroxidase activity in blood serum was used to evaluate the selenium status in pigs. A modified method for determination of tocopherol in fat tissue was described. The addition of 15 mg α-tocopheryl acetate/kg diet was demonstrated to be sufficient to maintain the tocopherol stores in body fat at an unchanged level.     

Studies on the (pro) insulin biosynthesis of islets of Langerhans of sand rats (Psammomys obesus).

By feeding a regular laboratory chow, sand rats (Psammomys obesus) from our breeding colony gained different body weights, though they received approximately the same quantity of calories. Sand rats, reaching a body weight above 160 g (group B) showed significantly increased blood glucose values in contrast to the animals with a body weight under 160 g (group A). Isolated pancreatic islets of these two groups of sand rats were incubated with [3H]-leucine to study the incorporation of this amino acid into proinsulin and insulin. The incorporation into proteins of pancreatic islets of sand rats of group B was stimulated by 0.45 mg and 3.0 mg/ml glucose. In group A there was no further stimulation from 0.45 mg to 3.0 mg/ml glucose. Insulin secretion could be stimulated by glucose in both groups, but the stimulation was stronger in group B than in group A.