Preferential X inactivation in human placenta membranes: Is the paternal X inactive in early embryonic development of female mammals?

Summary In placenta membranes of newborn girls carrying electrophoretically distinguishable G6PD alleles, the maternally derived isozyme is expressed preferentially. This phenomenon cannot be explained by allelic differences in enzyme activity or by somatic selection directed against cells with particular G6PD phenotypes. Instead, it may be that in this tissue X inactivation is nonrandom. Preferential expression of the maternal X chromosome, as has been shown in marsupials and in extraembryonic membranes of rodents and now in man, may reflect the state of activity of the X chromosomes in the early stages of female embryonic development.H.-H. R. is supported by the Deutsche Forschungsgemeinschaft     

Synchronization of Dunaliella cultures

Summary Dunaliella cells exhibit different temperature optima for photosynthesis and cell division. Using this observation a combined light-dark and highlow temperature treatment is given to synchronize cell suspensions.     

A novel labeling procedure of anteiso-fatty acid-containing lipids in staphylococci for investigating the effect of penicillin on lipid release

L-[4,5-3H]isoleucine was introduced to label anteiso-fatty acid (AIFA)-containing lipids in Staphylococcus aureus SG 511. After an overnight incubation in peptone broth in the presence of 37 kBq L-[4,5-3H]isoleucine/ml, 8.5-13% of the total radioactivity applied was found to be incorporated into the cells. 22.4-25.6% of the incorporated radioactivity was found in AIFA-containing lipids extracted by chloroform-methanol-water (2:1:0.2, v/v/v) at pH 2. The interphase contained 70-75% of the incorporated radioactivity. Lipoteichoic acid, extracted by phenol-water (80:20, w/v) contained less than 1% of the incorporated radioactivity, as measured after purification by hydrophobic interaction chromatography on octyl sepharose gel. Within 1 h after addition of 10 micrograms/ml penicillin G to exponentially growing cultures of S. aureus, that led to non-lytic death of the cells, 11.9-18.1% of the incorporated L-[4,5-3H]isoleucine label were released. Lipids containing AIFA were excreted to 5.4-8.4% of total incorporated activity; this amount represents more than 1/4 of the labeled cellular lipids.     

Experimentelle Untersuchung über die Induktionsleistungen der oberen Urmundlippe in älteren Urodelenkeimen

Ohne ZusammenfassungAusgeführt mit Unterstützung der Notgemeinschaft der Deutschen Wissenschaft.     

Über das Reaktionsspektrum von Rezeptoren aus der Riechschleimhaut von Wasserfröschen (Rana esculenta)

Zusammenfassung Aus dem Riechepithel von Rana esculenta wurden mit metallgefüllten Mikropipetten Aktionspotentiale einzelner Rezeptoren abgeleitet (Dauer 4–7 msec, maximale Frequenz 10 Imp./sec). Die Reaktionen von 25 Zellen auf 28 Duftstoffe werden beschrieben.Fast alle daraufhin geprüften Zellen reagieren auf Oenanthaldehyd, Amylacetat, Capronsäureäthylester und Caprylsäureäthylester mit einer Erhöhung der Impulsfrequenz (Grundspektrum). Außerdem haben die Rezeptoren ein variables Beispektrum geringen Umfanges.

---

Odor specificities of receptors in the olfactory epithelium of the frog Rana esculenta

Summary Action potentials from single receptors in the olfactory epithelium of water frogs (Rana esculenta) have been recorded by means of metal filled glass pipettes. The reactions of 25 cells to stimulation with 28 odorous substances are described. All cells so far tested showed an increase in spike frequency when stimulated with heptanal, amyl acetate, the ethyl ester of hexanoic acid, and the ethyl ester of octanoic acid, (basic spectrum). An additional small but variable reaction spectrum (side spectrum) was recorded.

---

---

Herrn Prof. Dr. H. Autrum zum 60. Geburtstag gewidmet.     

Everything’s Relative? Relative Differences in Processing Fluency and the Effects on Liking

Explanations of aesthetic pleasure based on processing fluency have shown that ease-of-processing fosters liking. What is less clear, however, is how processing fluency arises. Does it arise from a relative comparison among the stimuli presented in the experiment? Or does it arise from a comparison to an internal reference or standard? To address these questions, we conducted two experiments in which two ease-of-processing manipulations were applied: either (1) within-participants, where relative comparisons among stimuli varying in processing ease were possible, or (2) between-participants, where no relative comparisons were possible. In total, 97 participants viewed simple line drawings with high or low visual clarity, presented at four different presentation durations, and rated for felt fluency, liking, and certainty. Our results show that the manipulation of visual clarity led to differences in felt fluency and certainty regardless of being manipulated within- or between-participants. However, liking ratings were only affected when ease-of-processing was manipulated within-participants. Thus, feelings of fluency do not depend on the nature of the reference. On the other hand, participants liked fluent stimuli more only when there were other stimuli varying in ease-of-processing. Thus, relative differences in fluency seem to be crucial for liking judgments.