Does Dream Interpretation Have Any Limits? An Evaluation of Interpretations of the Dream of “Irma's Injection”

Dream interpretative efforts appear unconstrained by methodological standards. An examination of the re-interpretations of Freud's dream of Irma's Injection, the dream specimen of psychoanalysis, illustrates the undisciplined nature of dream interpretation. Reading in from presumed day residues or infantile experiences rather than out from the dream report per se lies at the heart of the problem. The failure to spell out inferences, to link inferences to the dream text, to explain and maintain the relationships in the dream report, and to offer a substitute text for the entire dream text all contribute to the inadequacies of dream interpreatation.     

Nidogen is nonessential and not required for normal type IV collagen localization in Caenorhabditis elegans

Nidogen (entactin) can form a ternary complex with type IV collagen and laminin and is thought to play a critical role in basement membrane assembly. We show that the Caenorhabditis elegans nidogen homologue nid-1 generates three isoforms that differ in numbers of rod domain endothelial growth factor repeats and are differentially expressed during development. NID-1 appears at the start of embryonic morphogenesis associated with muscle cells and subsequently accumulates on pharyngeal, intestinal, and gonad primordia. In larvae and adults NID-1 is detected in most basement membranes but accumulates most strongly around the nerve ring and developing gonad. NID-1 is concentrated under dense bodies, at the edges of muscle quadrants, and on the sublateral nerves that run under muscles. Two deletions in nid-1 were isolated: cg119 is a molecular null, whereas cg118 produces truncated NID-1 missing the G2 collagen IV binding domain. Neither deletion causes overt abnormal phenotypes, except for mildly reduced fecundity. Truncated cg118 NID-1 shows wild-type localization, demonstrating that the G2 domain is not necessary for nidogen assembly. Both nid-1 mutants assemble type IV collagen in a completely wild-type pattern, demonstrating that nidogen is not essential for type IV collagen assembly into basement membranes.     

Ein weiterer Versuch, die Orientierung von Brieftauben durch jahreszeitliche ?nderung der Sonnenh?he zu beeinflussen. Gleichzeitig eine Kritik der Theorie des Versuchs

Zusammenfassung Der Versuch, bei Brieftauben durch zeitweisen Entzug der Sonnensicht eine Orientierungstäuschung hervorzurufen, verlief auch im Herbst 1954 erfolglos. (Negativer Ausfall des ersten Wilhelmshavener Versuchs: K. undA. Rawson, diese Ztschr., dieses Heft, S. 168.)Dieser Ausfall spricht zunächst gegen dieMatthewssche Hypothese der Sonnennavigation, ohne jedoch unbedingt tödlich für sie zu sein (s. Diskussion, S. 176).Unabhängig von der Verschiedenheit der Versuchsergebnisse bedarf die Theorie des Warteversuchs einer Klärung. Durch Sonnenabschluß während der Warteperiode wird zwar eine Abnahme der Sonnenmittagshöhe bewirkt, die, für sich allein wahrgenommen, von den Tauben im Sinne einer Nordversetzung gedeutet werden könnte. Die Bahn aber, welche zum Scheitelpunkt führt, weicht ab von der Sonnenbahn, die am vorgetäuschten Heimatort unmittelbar vor der Warteperiode zu beobachten gewesen wäre. Soll also die Versuchserwartung (südwärts gerichtete Abflüge der Wartetauben unabhängig von der Tageszeit) aufrechterhalten werden, so muß die Navigationshypothese ergänzend präzisiert werden: Die Taube müßte ihre Position nicht nach beobachteten Bahnstückchen, sondern ausschließlich nach den aus ihnen erschlossenen Sonnenmittagspunkten errechnen, und zwar auch dann, wenn sie nie Gelegenheit hatte, die Mittagshöhe selber zu beobachten. Nur durch das Wieder-Vergessen der Bahnbeobachtungen könnte verständlich gemacht werden, daß z. B. frühmorgens am Versuchsort aufgelassene Wartetauben nicht ostwärts, sondern südwärts fliegen. (Hierzu Abb. 4.)Wenn beobachtete Abschnitte der Sonnenbahn ohne Vergleich mit vorher gesehenen Abschnitten zur Gewinnung der Scheitelhöhe taugen sollen, so muß die Taube die Fähigkeit der Kurvenextrapolation a priori besitzen. Da jede Sonnenbahn eine mathematische Individualität ist, kann der Taube dies grundsätzlich zugestanden werden, aber nur innerhalb der Wendepunkte (d. h. im konvexen Bereich der Sonnenbahn). Außerhalb derselben müßte die Taube versagen. Damit sind Anhaltspunkte für die weitere experimentelle Analyse aufgezeigt: Erstens muß in Cambridge geprüft werden, ob eine Korrelation zwischen Tageszeit und Abflugsrichtung (morgens: Ost; mittags: Süd; nachmittags: West) besteht, wie sie nach der Methode des empirischen Bahnvergleichs zu fordern ist. Zweitens kann überall geprüft werden, ob Tauben während des konkaven Verlaufs der Sonnenbahn unorientiert sind, wie nach der rein mathematischen Extrapolationsmethode zu fordern wäre.

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Summary The sun occlusion experiment as proposed byMatthews was again repeated with a negative result. (First repeat in Wilhelmshaven, also with a negative result: K. andA. Rawson, this volume p. 168.)This does not conform to the sun navigation hypothesis. Some possibilities how to interpret the conflict of results obtained by the two research groups (Cambridge and Wilhelmshaven) are suggested (see p. 176).Apart from the diverging facts, the sun occlusion experiment needs further theoretical clarification. By the experimental procedure a fall of the midday sun altitude is observable and could in fact be interpreted as caused by a north displacement. Yet the curves traced by the sun at the release position (after the occlusion period) and at the false home (before the occlusion period) are very different, except for their common vertex. If the pigeon is supposed to compare a fragment of the seen sun path with a homologous fragment of the remembered sun path, the positional interpretation will diverge the more fromMatthews' solstice home spot, the more the release time differs from noon. E. g., in the early morning time, the observed sun path is parallel to the remembered home sun path with a deviation in azimuth which must be interpreted as caused by a considerable longitudinal (westward) displacement. No difference in midday altitude is detectable to the bird.There is one way to save the expectation of southward departures regardless of time of day: If the pigeon has the gift to extrapolate seen fragments of any sun curve independently of previous experience, it might be argued that only the midday point is furtherly used (even if it was not observed but determined by extrapolation). It also might be assumed that the observed part of the sun curve is promptly erased from the memory of the bird after having led to the completion of the arc. Yet this procedure of determining the midday point, involving pure mathematics without any help of remembered parts of the sun curve, would be conceivable only within the convex-upwards part of the sun path (from 6. a. m. to 6 p. m. local time). So the question is left to further investigation whether pigeons are unorientatet before 6 and after 18 h in the summer half year. On the other hand, it should be ascertained in the Cambridge region if, in the departure of sun-occluded pigions, there is a correlation between initial directions and time of day as would be expected if the pigeon compares sun path fragments. In this case, experimentally treated pigeons released in the early morning hours should steer east; those released about midday, south; those released near sun-set, west.

     

pH-dependent conformational flexibility of the SARS-CoV main proteinase (M(pro)) dimer: molecular dynamics simulations and multiple X-ray structure analyses

The SARS coronavirus main proteinase (M(pro)) is a key enzyme in the processing of the viral polyproteins and thus an attractive target for the discovery of drugs directed against SARS. The enzyme has been shown by X-ray crystallography to undergo significant pH-dependent conformational changes. Here, we assess the conformational flexibility of the M(pro) by analysis of multiple crystal structures (including two new crystal forms) and by molecular dynamics (MD) calculations. The MD simulations take into account the different protonation states of two histidine residues in the substrate-binding site and explain the pH-activity profile of the enzyme. The low enzymatic activity of the M(pro) monomer and the need for dimerization are also discussed.     

Apoptosis of oligodendrocytes via Fas and TNF-R1 is a key event in the induction of experimental autoimmune encephalomyelitis

In experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis, immunization with myelin Ags leads to demyelination and paralysis. To investigate which molecules are crucial for the pathogenesis of EAE, we specifically assessed the roles of the death receptors Fas and TNF-R1. Mice lacking Fas expression in oligodendrocytes (ODCs) were generated and crossed to TNF-R1-deficient mice. To achieve specific deletion of a loxP-flanked fas allele in ODCs, we generated a new insertion transgene, expressing the Cre recombinase specifically in ODCs. Fas inactivation alone as well as the complete absence of TNF-R1 protected mice partially from EAE induced by the immunization with myelin ODC glycoprotein. The double-deficient mice, however, showed almost no clinical signs of EAE after immunization. Histological analysis revealed that demyelination was suppressed in CNS tissue and that lymphocyte infiltration was notably reduced. We conclude that the death receptors Fas and TNF-R1 are major initiators of ODC apoptosis in EAE. Although only moderate reduction of lymphocyte infiltration into CNS tissue was observed, the absence of these receptors appears to confer protection from demyelination and development of clinical disease.     

Cyclohexenyl nucleic acids: conformationally flexible oligonucleotides

Cyclohexenyl nucleic acid (CeNA) is a nucleic acid mimic, where the (deoxy)ribose sugar has been replaced by cyclohexenyl moieties. In order to study the conformation of cyclohexenyl nucleosides by NMR, the HexRot program was developed to calculate conformations from scalar coupling constants of cyclohexenyl compounds, analogous to the methods applied for (deoxy)ribose nucleosides. The conformational equilibria and the values of the thermodynamic parameters are very similar between a cyclohexenyl nucleoside [energy difference between ₂H³ (N-type) and ²H₃ (S-type) is 1.8 kJ/mol and equilibrium occurs via the eastern hemisphere with a barrier of 10.9 kJ/mol] and a natural ribose nucleoside (energy difference between N-type and S-type is 2 kJ/mol and equilibrium occurs via the eastern hemisphere with a barrier of 4–20 kJ/mol). The flexibility of the cyclohexenyl nucleoside was demonstrated by the fast equilibrium between two conformational states that was observed in a CeNA-U monomer, combined with the ₂H³ conformation of the cyclohexene moiety when incorporated into a Dickerson dodecamer and the ²H₃ conformation when incorporated in a d(5′-GCGT*GCG-3′)/d(5′-CGCACGC-3′) duplex, as determined by the NMR spectroscopy. This represents the first example of a synthetic nucleoside that adopts different conformations when incorporated in different double-stranded DNA sequences.