Polymorphisms within the HLA-DR3 haplotypes

HLA-DR molecules were isolated from eight different HLA-DR3 homozygous B-cell lines by immunoprecipitation with monoclonal antibodies, and they were subsequently analyzed by two-dimensional gel electrophoresis. We found that HLA-DR3 homozygous B-cell lines of consanguineous origin express two types of HLA-DR molecules. One type of HLA-DR molecule was present in all the cell lines tested, whereas the second DR molecule appears to be polymorphic. DNA isolated from the different HLA-DR3 homozygous cell lines was studied by Southern blot analysis to determine whether any DR restriction fragment length polymorphism could be observed. Polymorphisms detected at both the product and genomic level have been compared to each other, and their relations to the serological (HLA-DR) and cellular (HLA-D and LB-Q1) typing data will be discussed.No reprints available     

The Influence of Morphology on Prognosis in Acute Leukemia

The presence of definite cytoplasmic granulation in at least some of the malignant cells was used as the sole criterion to separate 156 patients with acute leukemia into two groups: 110 with myeloblastic (AML), and 46 with lymphoblastic or stem cell leukemia (ALL). The median survival from the onset of symptoms in patients with AML was 20 weeks, and those with ALL 37 weeks. The difference in survival in these two groups is much greater for patients under the age of 25 than for those over the age of 25.     

Appearance and some neurochemical features of nitrergic neurons in the developing quail digestive tract

Using immunocytochemistry, NADPH-diaphorase (NADPHd) histochemistry and electron microscopy, the appearance of nitrergic enteric neurons in different digestive tract regions of the embryonic, neonatal and adult quail was studied in whole mounts and sections. NADPHd was first expressed by embryonic day 4–5 in two distinct locations, namely the mesenchyme of the gizzard primordium and at the caeco-colonic junction. At embryonic day 6, nitrergic neurons had already begun to form a myenteric nerve network in the wall of the proventriculus, gizzard and proximal part of the large intestine and by embryonic day 9, a myenteric network was visualized along the entire digestive tract of the quail. At the level of the stomach, this network was confined to the area covered by the intermediate muscles. By embryonic day 12–13, the NADPHd-positive myenteric neurons in the wall of the distal parts of the blind-ending paired caeca also became organized into ganglia. From this developmental stage on, a submucous nitrergic nerve network, sandwiched between the lamina muscularis mucosae and the luminal side of the outer muscle layer, became prominent in the proventriculus and intestinal walls. In the adult quail, only a minority of the NADPHd-positive neurons stained for vasoactive intestinal polypeptide (VIP) along the intestine. VIP-immunoreactive (IR) cell bodies were frequent in the myenteric plexus but not in the submucous plexus, whereas there were considerable numbers of NADPHd-positive neurons in both these plexuses. Nitrergic fibres were also observed in the outer muscle layer, but were almost absent from the lamina muscularis mucosa and lamina propria, in contrast to the dense VIP-ergic innervation encircling the bases of the intestinal crypts.     

Occurrence,distribution and neurochemical features of small intestinal neurons projecting to the cranial mesenteric ganglion in the pig

The small intestine of the pig has been investigated for its topographical distribution of enteric neurons projecting to the cranial mesenteric ganglion, by using Fast Blue or Fluorogold as a retrogradely transported neuronal tracer. Contrary to the situation in small laboratory animals such as rat and guinea-pig, the intestinofugally projecting neurons in the porcine small intestine were not restricted to the myenteric plexus, but were observed in greater numbers in ganglia of the outer submucous plexus. The inner submucous plexus was devoid of labelled neurons. Retrogradely labelled neurons were mostly found, either singly or in small aggregates, in ganglia located within a narrow border on either side of the mesenteric attachment. For both nerve networks, their number increased from duodenum to ileum. All the retrogradely labelled neurons exhibited a multidendritic uniaxonal appearance. Some of them displayed type-III morphology and stained for serotonin. This study indicates that, in the pig, not only the myenteric plexus but also one submucous nerve network is involved in the afferent component of intestino-sympathico-intestinal reflex pathways. The finding that some of the morphologically defined type-III neurons participate in these reflexes is in accord with the earlier proposal that type-III neurons are supposed to fulfill an interneuronal role, whether intra- or extramurally.     

Effect of dimethylglycine and trimethylglycine (Betaine) on the response of Atlantic salmon (Salmo salar L.) smolts to experimental Vibrio anguillarum infection

Atlantic salmon (Salmo salar L.) were fed on a control diet or experimental diets containing betaine (15 mg g^-1) or dimethylglycine (DMG, I mg g^-1 or 5 mg g^-1). After 10 weeks of feeding, resistance to infection was assessed following inoculation with Vibrio anguillarum. Total blood and differential leucocyte counts were made, and plasma lysozyme and ceruloplasmin were assayed as non-specific humoral factors. The mortality during the bacterial exposure was of the same magnitude in all feeding groups. Betaine or DMG had no effect on the 'basal' levels of plasma total protein, lysozyme or ceruloplasmin, but 3 days postinjection the lysozyme and ceruloplasmin levels were higher in the control group compared with the experimental groups. In both DMG groups, the lymphocyte response took place 1-2 weeks earlier than in the control or betaine supplemented group indicating that DMG has an immunomodulating effect on salmon.     

Cloning,sequencing and enhanced expression of the Trichoderma reesei endoxylanase II (pI 9) gene xln2

The Trichoderma reesei xln2 gene coding for the pI 9.0 endoxylanase was isolated from the wild-type strain QM6a. The gene contains one intron of 108 nucleotides and codes for a protein of 223 amino acids in which two putative N-glycosylation target sites were found. Three different T. reesei strains were transformed by targeting a construct composed of the xln2 gene, including its promoter, to the endogenous cbh1 locus. Highest overall production levels of xylanase were obtained using T. reesei ALK02721, a genetically engineered strain, as a host. Integration into the cbh1 locus was not required for enhanced expression under control of the xln2 promoter.     

Involvement of fibronectin during epiboly and gastrulation in embryos of the common carp,Cyprinus carpio

Summary The present report firstly describes a pilot study in which, during early development of embryos of the common carp, Cyprinus carpio, the cellular adhesion to fibronectin (FN) was blocked by administration of GRGDS peptide (which binds to the FN-receptor). As this treatment resulted in developmental aberrations, suggesting a functional role for FN, the major part of the work was focussed on the distribution of reactivity of anti-FN antibodies during epiboly and gastrulation. GRGDS treatment had a concentration dependent effect on development. Incubation of embryos in 1.5 mg/ml from the 32-cell stage onwards caused a retardation of epiboly, which did not proceed beyond 60%. The embryos did not show involution, as was confirmed by histological study. These preliminary results suggest that FN is involved in both epiboly and gastrulation of carp embryos. During cleavage, no specific extracellular binding of anti-FN antiserum could be observed. However, binding to a number of cell membranes took place from early epiboly onwards. After the onset of gastrulation, we observed a gradually increasing number of the deepest epiblast cells, showing immunostaining on part of their surface, facing the yolk syncytial layer (YSL) or the involuted cells. During early epiboly, anti-FN binding was restricted to areas in front of the migratory hypoblast cells. Later on, binding was found at the border of hypoblast and epiblast cells. At 100% epiboly, some contact areas of epiblast and hypoblast showed a discontinuous lining of reactivity, whilst other areas appeared devoid of anti-FN binding sites. The results indicate that FN is involved in the migration and guidance of hypoblast cells during gastrulation in carp. Correspondence to: P. Gevers     

Expression of wild-type GBSS transgenes in the off-spring of partially and fully complementedamylose-free transformants of potato

Theamylose-free (amf) potato mutant can easily be complemented through introduction of the wild-type gene coding for granule-bound starch synthase (GBSS). After iodine staining the starch of theamf mutant is red whereas that of the wild type and the complementedamf mutant is blue. The level of complementation of selected transformants and their sexual off-spring after backcrossing withamf was investigated using sporophytic tuber cells and gametophytic microspore cells. Two diploid and two tetraploid transformants with full complementation demonstrated the expected segregation patterns of 1:1 (one active insert) or 3:1 (two independently segregating active inserts) in the microspores and in the F1 offspring based on staining of tubers. All expected genotypes in the F1 generation were found, based on microspore segregation patterns of the individual F1 plants. Two transformants with partial complementation (mixed phenotypes) were investigated. One of them, B1, was tetraploid and duplex for the GBSS insert, which had originated through mitotic doubling of the transformed diploid cells. In the F1 generation three phenotypic classes were found:amf, fully complemented and partially complemented. The latter two classes exist independently of a simplex or duplex gene status. The second transformant with partial complementation, B10, appeared to have a complex molecular composition. One cluster of five transgenes caused the partial complementation. Fully and partially complemented phenotypic classes were found after crossing B10 with theamf mutant. Indications were found that the ploidy level of the tissue in which the genes were introduced and expressed played an important role. Firstly, partial complementation was found after transformation of the diploid and not of the tetraploidamf genotypes. Secondly, the level of complementation was higher in tissue with lower ploidy levels, as illustrated by the colour of the starch inin vitro tubers (2x–4x cells) versus field-grown tubers (16x–64x).     

Region-Specific Cis- and Trans-Acting Factors Contribute to Genetic Variability in Meiotic Recombination in Maize

Understanding the genetic basis for variability in recombination rates is important for general genetic studies and plant-breeding efforts. Earlier studies had suggested increased recombination frequencies in particular F(2) populations derived from the maize inbred A188. A detailed phenotypic and molecular analysis was undertaken to extend these observations and dissect the responsible factors. A heritable increase in recombination in the sh1-bz1 interval was observed in these populations. A factor causing an approximate twofold increase mapped to the A188 Sh1-Bz1 region, behaved as a dominant, cis-acting factor, affected recombination equally in male and female sporogenesis and did not reduce the wellstudied complete interference in the adjacent bz1-wx interval. This factor also did not increase recombination frequencies in the c1-sh1 and bz1-wx intervals, demonstrating independent control of recombination in adjacent intervals. Additional phenotypic analysis of recombination in the c1-sh1 and bz1-wx intervals and RFLP analysis of recombination along chromosomes 7 and 5 suggested that heritable factors controlling recombination in these intervals act largely independently and in trans. Our results show that recombination in these populations, and possibly maize in general, is controlled by both cis- and transacting factors that affect specific chromosomal regions.