Deutungsversuch zur Nahrungsaufnahme eines schnabelverletzten Austernfischers(Haematopus ostralegus)

Zusammenfassung Eine MitteilungFlints über die Nahrungsaufnahme eines schnabelverletzten Austernfischers (Gefangenschaftsvogel) gab Anlaß zu einigen Gedanken darüber, welche angeborenen Verhaltensweisen dem Vogel bei der Erfindung seiner neuen Methode von Nutzen gewesen sein können. — So wird das Aufspießen von Brocken in der Futterschüssel mit dem Erbeuten von Muscheln und Krabben durch Aufspießen verglichen und das Herausschleudern des Bissens als Versuch gedeutet, einen Fremdkörper loszuwerden. Das beachtliche Hinstoßen des Brockens zu einer Rinne im Käfigboden wird als Surrogat für einen im Freileben vorkommenden zielgerichteten Nahrungstransport angesehen und im schließlichen Versenken des überstehenden Schnabelteils in der Rinne zum Fassen der Nahrung wird das normale Nahrungsstochern der Art erblickt. — Es wird eine Hypothese zur mutmaßlichen Entstehung der verblüffenden Umorientierung entwickelt.

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Summary A short note byFlint about the feeding habits of an Oystercatcher(Haematopus ostralegus) in captivity with only three quarters of his under bill gave reason for reflections which of the innate motor patterns of the species might have helped the bird in finding its new method. — At first a morsel of food in the tray is stabbed with the upper bill. This is compared with the stabbing of mussels and crabs. The morsel is then flung out of the tray in the way of getting rid of annoying matter. After this the bit is pushed along the floor towards a slit and right across it. This remarkable performance seems to be a substitute for an oriented food transport directed to a special place occurring under full scope conditions. The sinking of the beak into the cleft in order to seize the food at last may be identical with the usual probing for worms. — A conjecture is given as to how this bewildering reorganization of feeding habits might have come into being.

     

The reversal of phenylarsenoxide inhibition of keto acid oxidation in mitochondrial and bacterial suspensions by lipoic acid and other disulphides

1. Inhibition of pyruvate oxidation in suspensions of Aerobacter aerogenes cells and of isolated mitochondria from rat heart and liver by phenylarsenoxide is prevented by an excess of lipoic acid, whereas inhibition due to certain bivalent cations is not. 2. In both systems inhibition persists when the bacteria and mitochondria are recovered and resuspended in fresh media in the absence of the inhibitor. Persistent inhibition due to preincubation with phenylarsenoxide, but not with the metal ions, is reversed by lipoic acid and by certain other disulphides. 3. 2,3-Dimercaptopropan-1-ol prevents the inhibition of pyruvate oxidation by phenylarsenoxide and by bivalent cations in both mitochondria and bacterial cells. 4. In aerobic suspensions of mitochondria and bacteria disulphides such as lipoic acid are reduced rapidly to dithiols. Reduction is inhibited by Co(2+), Ni(2+), Cd(2+) and Zn(2+), but not by phenylarsenoxide. 5. It is concluded that the inability of lipoic acid to prevent the action of the metal ions on pyruvate oxidation is due to the inhibition of its reduction to the effective dithiol.     

Studies onAzotobacter species in soil

Summary Methods for countingAzotobacter species in soil have been examined. The highest counts were obtained from soil suspensions shaken in sterile distilled water containing 10-g glass beads and plated on to glucose agar. Mannitol has been rejected as a suitable substrate in agar media because it gives lower counts of Azotobacter than glucose, an effect which is further enhanced by drying the agar plates. A clear medium free from precipitated phosphate and CaCO₃ is recommended for the agar-plate method; the Azotobacter count is affected by the phosphate concentration.The agar-plate and dilution-tube methods were compared; the latter is less accurate but more convenient when many soil samples have to be examined.     

Zur Elektronenmikroskopie der Kerneinschlüsse im menschlichen Nebenhodenepithel

Zusammenfassung Es werden verschiedene Typen von Einschlußkörperchen im Karyoplasma der Epithelzellen des menschlichen Nebenhodenepithels beschrieben. Die verschieden strukturierten Kerninklusionen werden als eine Differenzierungsreihe aufgefaßt. Sie beginnt mit kleinen rundlichen Körperchen aus feinfädigem Material und führt über die Ausbildung von Anhäufungen dichter homogener Kugeln zu großen Vakuolen wechselnden Inhaltes.

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Summary Different types of inclusion bodies are described in the karyoplasm of the epithelial cells of the human epididymis. The structural differences between these inclusions are interpreted as being indicative of consecutive stages in the process of their formation. Thus small, spherical bodies consisting of a fine fibrous material are believed to be the initial stages in the formation of the inclusion bodies whereas the dense, homogenous globules are thought to represent a later stage. Large vacuoles containing different materials are regarded as the final stage in this process of differentiation.

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Herrn Professor Dr. W. Bargmann zum 60. Geburtstag gewidmet.

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Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Buchbesprechungen

Ohne Zusammenfassung     

Substitution of Manganese for Tomato Juice in the Cultivation of Lactic Acid Bacteria

Tomato juice was separated by chemical and physical methods into various active fractions, as measured by growth response and acid production by numerous lactic acid bacteria. Incineration of the treated extracts with little apparent loss in activity established the fact that the stimulatory component was of inorganic composition. Of the various cations tested, manganese was the only element that produced biological activity comparable to that of the original extract. Of the 71 strains of lactic acid bacteria tested, 63 strains showed a definite requirement for manganese or tomato juice.     

CYTOTAXONOMY OF TWELVE SPECIES OF HIBISCUS SECTION FURCARIA

Menzel, Margaret Y. (Florida State U., Tallahassee), and F. D. Wilson. Cytotaxonomy of twelve species of Hibiscus section Furcaria. Amer. Jour. Bot. 50(3): 262–271. Illus. 1963.—Metaphase-I chromosome numbers and pairing in 88 accessions showed that H. cannabinus, H. costatus, and H. surattensis are diploid (n = 18); and H. acetosella, H. aculeatus, H. bifurcatus, H.furcellatus, H. meeusei, H. radiatus, H. rostellatus and H. sabdariffa are tetraploid (n = 36), with similar low multivalent frequencies, hence probably allotetraploids each combining 2 well-differentiated genomes. No intraspecific variation in ploidy was found. Fertile, vigorous F₁ hybrids between H.furcellatus and H. bifurcatus showed complete chromosome pairing (n = 36), confirming a close relationship between the parents. Two African strains of H. diversifolius were octoploid (n = 72) with low multivalent frequency and hence probably contain 4 differentiated genomes. At least 4, perhaps 5 or 6, differentiated genome groups are represented in tropical Africa, and at least 2 in the American tropics.