Creation of a Sog morphogen gradient in the Drosophila embryo.

A variety of genetic evidence suggests that a gradient of Decapentaplegic (Dpp) activity determines distinct cell fates in the dorsal region of the Drosophila embryo, and that this gradient may be generated indirectly by an inverse gradient of the BMP antagonist Short gastrulation (Sog). It has been proposed that Sog diffuses dorsally from the lateral neuroectoderm where it is produced, and is cleaved and degraded dorsally by the metalloprotease Tolloid (Tld). Here we show directly that Sog is distributed in a graded fashion in dorsal cells and that Tld degradation limits the levels of Sog dorsally. In addition, we find that Dynamin-dependent retrieval of Sog acts in parallel with degradation by Tld as a dorsal sink for active Sog.     

Denaturation behaviour of DNA-protein-complexes detected in situ in metaphase chromosomes in suspension by Hoechst 33258 fluorescence.

The denaturation behaviour of DNA-protein complexes in metaphase chromosomes in suspension was analysed in situ by Hoechst 33258 fluorescence. The results indicate that due to the stability of the dye molecule and the product of the molecular extinction coefficient and the quantum yield at different temperatures, Hoechst 33258 is a suitable probe for the detection of double-stranded DNA. Thus, it is possible to monitor the concentration of double-stranded DNA in a suspension by measuring the total fluorescence intensity. The fluorescence denaturation profiles of DNA (calf thymus) were found to be comparable to absorption measurements. The decrease in fluorescence of metaphase chromosomes in suspension with increasing temperature may therefore be used to detect conformational changes of DNA in situ.     

Perlecan and its immunoglobulin like domain IV are abundant in vitreous and serum of the chick embryo.

Perlecan is a highly conserved heparan sulfate proteoglycan in cartilage and basement membranes. We identified chick perlecan and a 90 KD perlecan fragment in vivo using a newly generated monoclonal antibody. Chick perlecan is, like its human and mouse homologue, a hybrid heparan sulfate/chondroitin sulfate proteoglycan with a core protein of 400 KD. Analysis of the 90 KD fragment by Matrix Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) and Capillary LC nano Electrospray Ionization tandem MS (LC nano ESI MS/MS) showed that it belonged to domain IV of the perlecan core protein. We found that full-length perlecan and its domain IV fragment are abundant in embryonic vitreous body and serum. Their expression in vitreous and serum is greatly down-regulated shortly after hatching of the chick. We speculate that the abundance of perlecan in the embryonic circulation and vitreous reflects the ongoing formation of new BMs in the expanding vascular system and the growing retina. In addition, we found that perlecan as a substrate does not support, rather inhibits neurite outgrowth.     

Food provision to nestlings in the Hoopoe Upupa epops: implications for the conservation of a small endangered population in the Swiss Alps

In an attempt to recognize the possible ecological causes of the decline of a population of Hoopoes Upupa epops in the Swiss Alps, we collected data on resource exploitation. The prey provisioned to nestlings by parents was investigated at four breeding sites using photographs (n = 4353, 80% of which enabled prey identification). Molecrickets Gryllotalpa gryllotalpa and Lepidoptera (larvae and pupae) were dominant in nestling diet (93% frequency; 97% biomass). Although Molecrickets were provisioned less frequently (26%) than Lepidoptera (67%), they represented 68% of the total biomass (vs 29% for Lepidoptera). There was an overall negative relationship between the proportion of Molecricket biomass in the diet and the parents' feeding rate, whereas a comparison between broods showed that a higher provisioning activity did not lead to an increase in the biomass supplied to the chicks. A diet based on Molecrickets therefore appears to be energetically advantageous. As Molecrickets are a traditional prey of Hoopoes in central Europe, this might be relevant to other populations. In the study area, Molecrickets occur only on the intensively cultivated plain, whereas the majority of Hoopoe pairs nest at various altitudes on the foothills adjacent to the plain as the latter provides at present almost no suitable nesting sites. Hoopoes breeding higher up on the foothills seem to experience greater provisioning costs and have, on average, lower breeding success. Providing nest sites on the plain is the main conservation measure proposed for the local Hoopoe population. Further attention should also be paid to Molecrickets as these may be crucial for Hoopoes.     

Human Y chromosomes with two fluorescing bands after staining with Quinacrine derivates

Summary After staining with Quinacrine derivates we have observed Y-chromosomes with 2 brightly fluorescing bands in the distal part of the long arm. This pattern of fluorescence was found in 5 men, 4 of them having a long Y.

---

Zusammenfassung Nach Färbung mit Quinacrinderivaten beobachteten wir 2 helle Banden im distalen Abschnitt der langen Y-Arme. Dieses beim Y-Chromosom bisher nicht beschriebene Fluorescenzmuster wurde bei 5 Männern, von denen 4 ein langes Y hatten, gefunden.

---

---

Supported by the Deutsche Forschungsgemeinschaft.

---

Supported by the Landesamt für Forschung.     

De novo translocation t(Yq−; 15p+) in a malformed boy

Summary De novo translocation of an important portion of the long arm of the Y chromosome to the short arm of No. 15 was observed in a mentally defective boy exhibiting several abnormal features: cleft palate, contracted fingers, synostosis of the 4th and 5th metatarsal bones, narrow iliac wings. Endocrinological studies suggest extreme hypogonadism.     

Partielle Trisomie des kurzen Arms eines Chromosoms Nr. 4 in der Folge einer Translokation t(4p-22p+)

Zusammenfassung Eine partielle Trisomie des kurzen Armes eines Chromosoms 4 wurde bei einem 3 Jahre alten mikrocephalen, in seiner geistigen Entwicklung retardierten Kind festgestellt. Diese Aberration ergab sich bei einer reziproken Translokation t(4p-22p+), die bei der Mutter, dem Großvater und 2 Geschwistern vorliegt.

---

Partial trisomy of the short arm of chromosome 4 due to translocation t(4p-22p+)

Summary Partial trisomy of the short arm of chromosome 4 was found in a 3-year-old microcephalic, mentally retarded girl. This aberration resulted from a reciprocal translocation t(4p-22p+) present in the mother, the grandfather and both siblings.

     

Cyclic Expression of A Nuclear Protein In A Dinoflagellate

Nuclei of the dinoflagellate Crypthecodinium cohnii strain Whd were isolated and nuclear proteins were extracted in three fractions, corresponding to the increasing affinity of these proteins to genomic DNA. One fraction contained two major bands (48- and 46-kDa) and antibodies specific to this fraction revealed two major bands by Western blot on nuclear extracts, corresponding to the 46- and 48-kDa bands. The 48-kDa protein was detected in G1 phase but not in M phase cells. An expression cDNA library of C. cohnii was screened with these antibodies, and two different open reading frames were isolated. Dinoflagellate nuclear associated protein (Dinap1), one of these coding sequences, was produced in E. coli and appeared to correspond to the 48-kDa nuclear protein. No homologue of this sequence was found in the data bases, but two regions were identified, one including two putative zinc finger repeats, and one coding for two potential W/W domains. The second coding sequence showed a low similarity to non-specific sterol carrier proteins. Immunocytolocalization with specific polyclonal antibodies to recombinant Dinap1 showed that the nucleus was immunoreactive only during the G1 phase: the nucleoplasm was immunostained, while chromosome cores and nuclear envelopes were negative.