Limited Tryptic Proteolysis of the Benzodiazepine Binding Proteins in Different Species Reveals Structural Homologies

Peptide mapping can be used to elucidate further the structural similarities of the benzodiazepine binding proteins in different vertebrate species. Crude synaptic membrane preparations were photoaffinity-labeled with [3H]flunitrazepam and subsequently degraded with various concentrations of trypsin. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by fluorography allowed a comparison of the molecular weights of photolabeled peptides in different species. Tryptic degradation led to a common peptide of 40K in all species investigated, a finding indicating that the benzodiazepine binding proteins are structurally homologous in higher bony fishes and tetrapods.     

Oenothera mitochondrial orf454, a gene involved in cytochrome c biogenesis corresponds to orf169 and orf322 of Marchantia

We have characterized a mitochondrial gene in Oenothera, designated orf454, capable of encoding a component of the cytochrome c biogenesis system. This open reading frame is interrupted by an intron of 941 nucleotides showing high similarity to a group II intron residing in the rpl2 gene. RNA editing, which is observed at 18 cytidine positions within the orf454 reading frame, improves the similarity to protein-coding sequences in bacteria and higher plants and removes the last 16 amino acids. orf454 also shows high sequence similarity to two overlapping reading frames (orf169 and orf322) of Marchantia mitochondria. These ORFs belong to an operon-like cluster of genes in the liverwort that is not conserved in Oenothera mitochondria. However, in bacteria these reading frames are organized like the Marchantia gene cluster. It has been shown by genetical analysis in Rhodobacter capsulatus that these genes are essential for cytochrome c biogenesis. Genes of bacterial operons — ccl1 in Rhodobacter and yejR and nrfE in Escherichia coli — show high sequence similarity to the mitochondrial reading frames orf577 and orf454 of Oenothera. orf454, which we describe here, is homologous to the C-terminal region of these bacterial genes, while the previously described orf577 is homologous to the N-terminal region.     

Population,formal genetics,and linkage relations of the phosphoglycolate phosphatase (PGP)—E.C.3.1.3.18

Summary One hundred and sixty-seven blood donors, 26 families with 72 offspring and 12 motherchild couples were studied for the phosphoglycolate phosphatase polymorphism. In hemolysates, the isozymes are stable for at least five weeks. The distribution of observed phenotypes in the population study did pot diverge from the expected values according to Hardy-Weinberg law. In the family study, the formal genetic model of three alleles—PGP ¹, PGP ² and PGP ³ at one autosomal locus-could be confirmed. Among 33 individuals from a Mongoloid population PGP 1 was observed in 100%. This observation lead us to the conclusion, based also on recent data in Negroid populations (Barker and Hopkinson 1978), that phosphoglycolate phosphatase may be a more recent polymorphism of Caucasoid populations. Linkage studies with the hp locus an chromosome 16 resulted in 19 meiotic divisions of 4 informative families in a lod score peak of 0.23 at =0.25 being inconclusive. The inclusion of the PGP system in paternity testing is also discussed.     

Mapping of the gene for X-chromosomal split-hand/split-foot anomaly to Xq26–q26.1

A large inbred kindred from Pakistan in which an isolated type of split-hand/split-foot anomaly is transmitted as an X-chromosomal trait has previously been described. An X/autosomal translocation and an X-chromosomal rearrangement have been excluded by cytogenetic studies. In order to map the gene responsible for this disorder, linkage analysis has been performed by using 14 highly polymorphic DNA markers distributed over the whole X chromosome. Two-point linkage analysis between the disease locus and X-chromosomal marker loci gives maximal lod scores at = 0.00 with the loci DXS294 (Z _max= 5.13) and HPRT (Z _max= 4.43), respectively, suggesting that the gene for the X-chromosomal split-hand/split-foot anomaly is localized at Xq26–q26.1.     

Parental mean ages and birth order in different types of congenital heart defects

Summary This study has shown that in some of the most common congenital cardiac malformations, such as valvular aortic stenosis, coarctation of the aorta, pulmonary stenosis, atrial and ventricular septal defect and tetralogy of Fallot the mean parental age and the birth order are not involved in the genesis of these lesions. A birth-order effect was only found in patent ductus arteriosus. First-born children are significantly affected more often than later-born siblings. The maternal as well as the paternal mean age is lower in this cardiac lesion. This suggests toward causative factors which may be present mainly during the first pregnancy and in primogenitures. Hypoxia could be one of these factors. If is postulated that in the presence of a polygenetically determined predisposition to this condition hypoxia may prevent closure of the ductus arteriosus. These investigations show that the original method of Haldane-Smith cannot be used for the analysis of the birth order effects on congenital malformations of the heart since the sibships are often incomplete. A corrective method described by Vogel is a good aid for such investigations.

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Zusammenfassung Bei einer Reihe häufiger Herzfehler—valvulären Aortenstenosen, Aortenisthmusstenosen, Pulmonalstenosen, Vorhof-und Ventrikelseptumdefekten und der Fallotschen Tetralogie—sind das elterliche Alter sowie die Stellung in der Geburtenreihe nach unseren Untersuchungen ohne Bedeutung für die Mißbildungsentstehung. Dagegen haben wir das Vorliegen eines Geburtenordnungseffektes beim Ductus arteriosus Botalli bestätigen können. Erstgeborene Kinder werden signifikant häufiger betroffen. Es ist sowohl das durchschnittliche Alter der Probandenväter als auch das der Mütter herabgesetzt. Daraus darf man folgern, daß weder ein väterlicher noch ein mütterlicher Effekt, sondern vielmehr ein Effekt, der mit der Erstschwangerschaft und Erstgeburt als solcher zusammenhängt, vorliegt. Als Erklärung hierfür bietet sich die Sauerstoffmangelhypothese an. Ein relativer Sauerstoffmangel post partum ist vermutlich am besten geeignet, bei entsprechender polygen determinierter Erkrankungsbereitschaft den Schließungsprozeß des Ductus arteriosus Botalli zu hemmen.Aus unseren Untersuchungen hat sich weiterhin ergeben, daß das Originalverfahren von Haldane-Smith für Untersuchungen der Geburtenordnung bei angeborenen Herzfehlern ungeeignet ist, da in den Familien der Probanden die Geschwisterreihen öfter nicht abgeschlossen sind, was eine Voraussetzung für die Anwendung dieser Methode ist. Dagegen bewährt sich eine Korrektur des Haldane-Smith-Verfahrens für unabgeschlossene Geschwisterreihen nach Vogel.

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This investigation was supported by the Deutsche Forschungsgemeinschaft, SFB 89 Kardiologie.     

Reference Intervals for N-Terminal Pro-B-Type Natriuretic Peptide in Amniotic Fluid between 10 and 34 Weeks of Gestation

Background

In adult and pediatric cardiology, n-terminal pro-B-type natriuretic peptide (nt-proBNP) serves as biomarker in the diagnosis and management of cardiovascular dysfunction. Elevated levels of circulating nt-proBNP are present in fetal conditions associated with myocardial pressure or volume load. Compared to fetal blood sampling, amniocentesis is technically easier and can be performed from early pregnancy onwards. We aimed to investigate amniotic fluid (AF) nt-proBNP concentrations in normal pregnancies between 10 and 34 weeks of gestation.

Methods

Nt-proBNP and total protein (TP) was measured in AF by chemiluminescence assay (photometry, respectively). To adjust for a potential dilutional effect, the AF-nt-proBNP/AF-TP ratio was analyzed. Reference intervals were constructed by regression modeling across gestational age.

Results

132 samples were analyzed. A negative correlation between AF-nt-proBNP/AF-TP ratio and gestational age was observed. Curves for the mean and the 5% and 95% reference interval between 10 and 34 weeks of gestation were established.

Conclusion

In normal pregnancy, nt-proBNP is present in AF and decreases during gestation. Our data provide the basis for research on AF-nt-proBNP as biomarker in fetal medicine.