Ha-ras-1 alleles in Norwegian lung cancer patients

Summary We have examined DNA restriction fragment length polymorphisms (RFLP) of the Ha-ras-1 gene in DNA from 118 lung cancer patients and 123 unaffected controls. When DNA samples were digested with MspI/ HpaII restriction endonucleases. Southern blot analysis demonstrated 4 common, 4 intermediate and 7 different rare alleles in the combined population after hybridization to the pGDa1 probe. Six of the rare alleles were unique for the lung cancer group and 1 rare allele for the control group. The frequency of rare alleles in lung cancer patients (10/236) was significantly different (P<0.01) from the control group (1/246). The lung cancer group also had a significantly lower frequency of the common 2.57 kb fragment than the controls (P<0.02). The results thus indicate that Ha-ras genotyping may be of value in lung cancer risk assessment.     

Cystic fibrosis typing with DNA probes and screening for ΔF508 deletion in families from Southern France

Summary A sample of 235 individuals from 49 French cystic fibrosis (CF) families with at least one living affected child was typed with probes for restriction fragment length polymorphisms (RFLPs) known to be linked to the CF gene, and was screened for the ΔF508 mutation. Using a combination of six probes, 44 out of the 49 families were sufficiently informative to enable prenatal diagnosis or carrier determination. As in many other populations, linkage disequilibrium was found between the CF locus and the haplotype B (XV2c: allele 1; KM19: allele 2), which accounts for about 78% of CF chromosomes in our families. The ΔF508 deletion was present in 64.3% of CF chromosomes.     

Somatic hybrid plants produced by electrofusion between dihaploid potatoes: BF15 (H1), Aminca (H6) and Cardinal (H3)

In order to regenerate somatic hybrids, mesophyll protoplasts from a dihaploid potato, BF15 (H1), were electrofused with those from two other dihaploid clones, Aminca (H6) and Cardinal (H3). Determination of the ploidy level by flow cytometry showed that 10% of plants regenerated from the fusion experiment with BF15 + Aminca were diploids, 14% triploids, 63% tetraploids and very few were mixoploids or had a higher ploidy level. Using morphological markers and vigour in plant growth, we were able to recover a total of 24 somatic hybrid plants, respectively 20 and 4 hybrids (accounting for 12% and 13% of regenerants) from the fusions BF15 + Aminca and BF15 + Cardinal. Most of the somatic hybrids were at the expected tetraploid level (2n=4x=48). The hybrid nature was confirmed by examining isoenzyme patterns for malate dehydrogenase (MDH) and isocitrate dehydrogenase (ICD).     

The receptor of calcitonin gene-related peptide (CGRP) is present on the membranes of insulinoma

We demonstrate here that membranes prepared from beta cells which release insulin contain specific binding sites for calcitonin gene-related peptide (CGRP). The binding of 125I(His) human CGRP to beta cell membranes was protein concentration, time, temperature and pH dependent. Scatchard analysis of the data revealed a single class of binding sites with an apparent dissociation constant (Kd) of 1.5 nM and a maximal binding capacity of 19 fmol/mg of protein. Chicken CGRP inhibited the label binding whereas salmon calcitonin had only a weak effect. These results suggest that the effect of CGRP on insulin secretion is due to a direct action on beta cells.     

Bacterial siderophores : structure and NMR assignment of pyoverdins Pa,siderophores ofPseudomonas aeruginosa ATCC 15692

Summary In iron-deficient conditions,Pseudomonas aeruginosa ATCC 15692 synthesizes two major siderophores, pyoverdins Pa and pyoverdin Pa B. Two other compounds, pyoverdin Pa A (occurring from hydrolysis of pyoverdin Pa during the culture) and pyoverdin Pa C (occurring artifactually during the purification procedure) were also isolated. All these compounds possess the same partly cyclic peptide chain wherel-Orn(OH · HCO) isN -formyl,N -hydroxy-l-ornithine. The chain is bound to a chromophore derived from 2,3-diamino-6,7-dihydroxyquinoline and having the (S) configuration. The four pyoverdins differ only in the acyl substituent bound to the nitrogen atom bound to carbon C3 of the chromophore. This is succinamide (pyoverdin Pa), succinic acid (pyoverdin Pa A), methyl succinate (pyoverdin Pa C) and 2-oxoglutaric acid (pyoverdin Pa B). The complete¹H- and¹³CNMR assignments, using two-dimensional total correlation NMR spectroscopy (TOCSY) and rotating-frame Overhauser enhancement spectroscopy (ROESY) procedures, as well as¹H-¹³C correlations, are reported. The complete sequence of the peptide using CH-NH correlations was achieved by NMR and confirmed the partly cyclic structure earlier reported using fast-atom-bombardment mass spectrometry (FAB-MS) on the siderophores and their dansylated fragments [Briskot G, Taraz K, Budzikiewicz H (1989)Liebigs Ann Chem: 375–384]. The use of these NMR procedures appears to be a tool of choice and a complementary approach to FAB-MS in the structure determination of some complex pyoverdins.Abbreviations Ser serine - Arg arginine - Thr ethreonine - Lys lysine - OHOrn N -hydroxyornithine - Chr chromophore     

A new recombinant procoagulant protein derived from the cDNA encoding human factor VIII

We have constructed new B domain deletion derivatives of human factor VIII (FVIII) by manipulating the cDNA using recombinant DNA techniques. One of these new derivatives, FVIII delta II, in which amino acids 771(pro)-1666(asp) have been deleted, no longer contains the protease cleavage site at amino acid position 1648(arg)-1649(glu) known to be involved in the initial step of FVIII processing. We have expressed this molecule in both baby hamster kidney (BHK) 21 cells using the vaccinia virus (VV) expression system and have established Chinese hamster ovary (CHO) derived permanent cell lines expressing either recombinant (r)FVIII or FVIII delta II. The characteristics of FVIII delta II have been compared to those of rFVIII and/or plasma derived (pd) FVIII. FVIII delta II has the following properties: (i) it exhibits FVIII procoagulant activity; (ii) it is expressed at 5-fold higher levels than is the complete molecule in comparable systems; (iii) it migrates for the most part as a single major band on SDS-PAGE, in contrast to the complete molecule; (iv) it is activated to a greater extent by thrombin than is either rFVIII or pdFVIII; and (v) it retains the ability to bind von Willebrand factor (vWf).     

Glomerular bypass shunts in the kidney of the Atlantic hagfish,Myxine glutinosa

Summary The vascular pathways associated with the glomerulus of the Atlantic hagfish, Myxine glutinosa have been studied by scanning electron microscopy of corroded resin casts of the vasculature. Although the overall pattern of the renal vasculature did not differ from earlier reports, a previously unreported vascular pathway which arose from the renal artery and bypassed the glomerular capillaries in 28% of glomeruli was clearly demonstrated. Glomerular bypass shunts either ran to join the loose capillary network around Bowman's capsule and thereby drain into the network of vessels associated with the mesonephric duct (ureter), or ran directly into the ureteral system of vessels and subsequently into the posterior cardinal veins. Glomerular bypass shunts which theoretically permit renal arterial blood to bypass the process of filtration may play a role in the regulation of body fluid volume.