Forgive and Forget: Differences between Decisional and Emotional Forgiveness

To forgive and forget is a well-known idiom, which has rarely been looked at empirically. In the current experiment, we investigated differences between emotional and decisional forgiveness on forgetting. The present study provides the first empirical support that emotional forgiveness has a strong influence on subsequent incidental forgetting. Specifically, our results demonstrate that emotional forgiveness leads to substantially higher levels of forgetting in respect to offense relevant traits compared to both decisional forgiveness and no forgiveness. This provides evidence for our hypothesized effect that only individuals who have emotionally forgiven a transgression, and not those who just decided to forgive, subsequently forget offense relevant traits attributed to the transgressor.     

Generation of New Hairless Alleles by Genomic Engineering at the Hairless Locus in Drosophila melanogaster

Hairless (H) is the major antagonist within the Notch signalling pathway of Drosophila melanogaster. By binding to Suppressor of Hairless [Su(H)] and two co-repressors, H induces silencing of Notch target genes in the absence of Notch signals. We have applied genomic engineering to create several new H alleles. To this end the endogenous H locus was replaced with an attP site by homologous recombination, serving as a landing platform for subsequent site directed integration of different H constructs. This way we generated a complete H knock out allele H ^attP, reintroduced a wild type H genomic and a cDNA-construct (H ^gwt, H ^cwt) as well as two constructs encoding H proteins defective of Su(H) binding (H ^LD, H ^iD). Phenotypes regarding viability, bristle and wing development were recorded, and the expression of Notch target genes wingless and cut was analysed in mutant wing discs or in mutant cell clones. Moreover, genetic interactions with Notch (N ⁵⁴¹⁹) and Delta (Dl ^B2) mutants were addressed. Overall, phenotypes were largely as expected: both H ^LD and H ^iD were similar to the H ^attP null allele, indicating that most of H activity requires the binding of Su(H). Both rescue constructs H ^gwt and H ^cwt were homozygous viable without phenotype. Unexpectedly, the hemizygous condition uncovered that they were not identical to the wild type allele: notably H ^cwt showed a markedly reduced activity, suggesting the presence of as yet unidentified regulatory or stabilizing elements in untranslated regions of the H gene. Interestingly, H ^gwt homozygous cells expressed higher levels of H protein, perhaps unravelling gene-by-environment interactions.     

Cytokeratin domains involved in heterotypic complex formation determined by in-vitro binding assays

Cytokeratins are constituent proteins of intermediate filaments (IFs) that form heterotypic tetrameric IF subunits containing two polypeptide chains of each of the two cytokeratin subfamilies, i.e. the acidic (type I) and the basic (type II). To locate the molecular domains involved in the formation of these heterotypic complexes, we have developed a binding assay in which total cellular or cytoskeletal polypeptides, or proteolytically prepared cytokeratin fragments, are separated by one-, or two-dimensional gel electrophoresis, blot-transferred on to nitrocellulose paper and probed with radio-iodinated purified cytokeratin polypeptides or fragments thereof, using buffers of various ionic strengths with or without 4 M-urea. Using these polypeptides in the binding assay, specific heterotypic binding was observed between complementary cytokeratin polypeptides of the two subfamilies (but not with other IF proteins) and between the corresponding alpha-helical rod domain fragments. Both rod coils 1 and 2 of the type II cytokeratin 8 bound to the rod (coils 1 and 2) fragment of type I cytokeratins, and this binding occurred at both low and high ionic strengths. The results obtained indicate that: (1) the binding between cytokeratin polypeptides of the complementary type is stronger and more selective than interactions of cytokeratins with other IF and non-IF proteins; (2) both the head and the tail portions of the proteins are not required for heterotypic complex formation; (3) the complementarity information located in the alpha-helical portions of the rod domain, and in short sequences immediately flanking them, is sufficient to discriminate between the two types of cytokeratins and to secure the formation of heterotypic cytokeratin complexes; (4) both coils 1 and 2 of the rod can contribute to this association; and (5) the formation of the heterotypic cytokeratin complex is not critically dependent upon ionic interactions. Our results are further compatible with the concept that the heterotypic binding takes place between cytokeratin homodimer coiled-coils.     

Optimizing purebred selection for crossbred performance using QTL with different degrees of dominance

A method was developed to optimize simultaneous selection for a quantitative trait with a known QTL within a male and a female line to maximize crossbred performance from a two-way cross. Strategies to maximize cumulative discounted response in crossbred performance over ten generations were derived by optimizing weights in an index of a QTL and phenotype. Strategies were compared to selection on purebred phenotype. Extra responses were limited for QTL with additive and partial dominance effects, but substantial for QTL with over-dominance, for which optimal QTL selection resulted in differential selection in male and female lines to increase the frequency of heterozygotes and polygenic responses. For over-dominant QTL, maximization of crossbred performance one generation at a time resulted in similar responses as optimization across all generations and simultaneous optimal selection in a male and female line resulted in greater response than optimal selection within a single line without crossbreeding. Results show that strategic use of information on over-dominant QTL can enhance crossbred performance without crossbred testing.     

Occurrence and distribution of muscle spindles in masticatory and suprahyoid muscles of the rat.

The occurrence and distribution of muscle spindles was studied in histochemically and conventionally stained serial cross sections of 6-week-old and adult rat masticatory and suprahyoid muscles. Spindles were present in moderate to large numbers in jaw closers, but they were absent in jaw openers and two of four muscles of an accessory suprahyoid group. In jaw closers, 67% or more of the total spindle population was concentrated relatively distant from the temporomandibular joint, in muscle portions which contained large numbers of extrafusal fibers reacting strongly for oxidative enzymes. Because of their location, spindles in these portions should be stretched more and, subsequently, should respond with a greater afferent discharge at any given muscle length than spindles situated nearer to the joint. Spindles in jaw closers, especially the medial pterygoid and deep masseter, often occurred in clusters and complex forms near the terminal branching of intramuscular nerve trunks. No such concentrations were seen in the two muscles of the accessory suprahyoid group that had spindles. The association in jaw closers of spindles with extrafusal fibers high in oxidative enzyme activity is consistent with the view that spindles are the sensory component of a reflex system that recruits these fibers for finely-graded contractions in response to small internal length-changes of the muscle (Botterman et al., '78); however, in jaw openers and two muscles of the accessory suprahyoid group, the absence of spindles, coupled with the presence of large populations of extrafusal fibers high in oxidative enzyme activity, is not easily reconciled with this concept.     

A study on the minimum number of loci required for genetic evaluation using a finite locus model

For a finite locus model, Markov chain Monte Carlo (MCMC) methods can be used to estimate the conditional mean of genotypic values given phenotypes, which is also known as the best predictor (BP). When computationally feasible, this type of genetic prediction provides an elegant solution to the problem of genetic evaluation under non-additive inheritance, especially for crossbred data. Successful application of MCMC methods for genetic evaluation using finite locus models depends, among other factors, on the number of loci assumed in the model. The effect of the assumed number of loci on evaluations obtained by BP was investigated using data simulated with about 100 loci. For several small pedigrees, genetic evaluations obtained by best linear prediction (BLP) were compared to genetic evaluations obtained by BP. For BLP evaluation, used here as the standard of comparison, only the first and second moments of the joint distribution of the genotypic and phenotypic values must be known. These moments were calculated from the gene frequencies and genotypic effects used in the simulation model. BP evaluation requires the complete distribution to be known. For each model used for BP evaluation, the gene frequencies and genotypic effects, which completely specify the required distribution, were derived such that the genotypic mean, the additive variance, and the dominance variance were the same as in the simulation model. For lowly heritable traits, evaluations obtained by BP under models with up to three loci closely matched the evaluations obtained by BLP for both purebred and crossbred data. For highly heritable traits, models with up to six loci were needed to match the evaluations obtained by BLP.     

Das UV-Sehen der V?gel: Neue Ergebnisse über den spektralen Sehbereich der V?gel

Zusammenfassung Ergebnisse aus einem mikrospektrophotometrischen sowie einem verhaltensphysiologischen Versuchsansatzes zeigen, daß der SonnenvogelLeiothrix lutea einen eigenständigen UV-Zapfentyp besitzt und eine sehr hohe Empfindlichkeit im UV-Teil des Spektrums aufweist. Diese Befunde werden mit den Ergebnissen anderer Autoren verglichen, die zeigen, daß eine Vielzahl von Vogelarten UV-empfindlich ist (entweder mit einem UV-Rezeptor oder eingeschränkt mit einem Violett-Rezeptor). Diese UV-Empfindlichkeit könnten Vögel nützen zur Orientierung am Polarisationsmuster der Sonne, zur Art-und/oder Partnererkennung, bzw. zur Nahrungssuche.

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UV vision in birds: A summary of latest results concerning the extended spectral range of birds

The results of a microspectrophotometric and a behavioural test present evidence that the passeriform birdLeiothrix lutea (Timaliidae) possesses a genuine UV cone type and is highly sensitive in the UV part of the spectrum. Those data are in accordance with results of other tests indicating that a majority of bird species is UV sensitive (either by a UV cone type or somewhat limited by a violet cone typ). Possible use of this extended sensitivity like orientation according to the polarisation pattern of the sky, species and/or mate recognition and food detection are discussed.