Effects of recombinant human gamma interferon on intracellular survival of Bordetella pertussis in human phagocytic cells

Abstract Several studies have demonstrated that Bordetella pertussis has the ability to enter and survive intracellularly within human polymorphonuclear leukocytes (PMNL) and human monocytes/macrophages. The effects of human recombinant gamma interferon (IFN-γ) on the survival of B. pertussis in PMNL and human monocytes, and on the oxidative burst activity of PMNL and human monocytes in response to B. pertussis were assessed in this study. IFN-γ partially increased intracellular killing of phagocytosed B. pertussis in human monocytes, as determined by an orange acridine-crystal violet assay. In contrast, IFN-γ did not enhance intracellular killing of B. pertussis in PMNL. No significant increase of superoxide production was noted in human monocytes in response to B. pertussis when stimulated with various concentrations of IFN-γ. The partial increase of B. pertussis killing by IFN-γ within monocytes, together with poor production of superoxide may explain how B. pertussis can survive within human phagocytic cells, and thus cause a more prolonged course of the disease.     

Heritability of adult body height: a comparative study of twin cohorts in eight countries.

A major component of variation in body height is due to genetic differences, but environmental factors have a substantial contributory effect. In this study we aimed to analyse whether the genetic architecture of body height varies between affluent western societies. We analysed twin data from eight countries comprising 30,111 complete twin pairs by using the univariate genetic model of the Mx statistical package. Body height and zygosity were self-reported in seven populations and measured directly in one population. We found that there was substantial variation in mean body height between countries; body height was least in Italy (177 cm in men and 163 cm in women) and greatest in the Netherlands (184 cm and 171 cm, respectively). In men there was no corresponding variation in heritability of body height, heritability estimates ranging from 0.87 to 0.93 in populations under an additive genes/unique environment (AE) model. Among women the heritability estimates were generally lower than among men with greater variation between countries, ranging from 0.68 to 0.84 when an additive genes/shared environment/unique environment (ACE) model was used. In four populations where an AE model fit equally well or better, heritability ranged from 0.89 to 0.93. This difference between the sexes was mainly due to the effect of the shared environmental component of variance, which appears to be more important among women than among men in our study populations. Our results indicate that, in general, there are only minor differences in the genetic architecture of height between affluent Caucasian populations, especially among men.     

Anatomical studies of branchlet abscission related to crown modification in Quercus cerris L.

The basic anatomy of lateral twig insertion onto the main branch in both healthy and damaged Quercus cerris L. trees was studied. An abscission zone is always present: in healthy trees it is formed by a smaller number of cell layers than in damaged ones, where it is more evident with many layers of cells. Cells of the abscission zone are roundish, with many intercellular spaces between them; cell walls are thin, non-lignified and without secondary walls. No starch was found in cells of the abscission zone, where, instead, a few scattered calcium oxalate druses are seen.     

Human alpha 3(VI) collagen gene. Characterization of exons coding for the amino-terminal globular domain and alternative splicing in normal and tumor cells

We recently reported the isolation and sequencing of human cDNA clones corresponding to the alpha 3 chain of type VI collagen (Chu, M.-L., Zhang, R.-Z., Pan, T.-c., Stokes, D., Conway, D., Kuo, H.-J., Glanville, R., Mayer, U., Mann, K., Deutzmann, R., and Timpl, R. (1990) EMBO J. 9, 385-393). The study indicates that the amino-terminal globular domain of the alpha 3(VI) chain consists of nine repetitive subdomains of approximately 200 amino acid residues (N1-N9) and the gene appeared to undergo alternative splicing since some clones lacked regions encoding the N9 and part of the N3 subdomains. In the present study, we report the exon structure for the region encoding the amino-terminal globular domain of the human alpha 3(VI) chain. The nine repetitive subdomains are encoded by 10 exons spanning 26 kilobase pairs of genomic DNA. Eight of the repetitive subdomains (N2-N9) were found to be encoded by separate exons of approximately 600 base pairs each. The only exception is the N1 subdomain which is encoded by two exons of 417 and 146 base pairs. Characterization of the exon/intron structure showed that the cDNA variants were the result of splicing out of exon 9 (encoding the N9 subdomain) and part of exon 3 (encoding the N3 subdomain). Nuclease S1 analysis and the polymerase chain reaction demonstrated that exon 7 (N7 subdomain) was also subject to alternative splicing in normal skin fibroblasts. Examination of these splicing events by nuclease S1 analysis in normal fibroblasts, three different human tumor cell lines, and several human tissues showed that splicing out of exon 9 is much more efficient in normal as compared to tumor cells.     

The exon organization of the triple-helical coding regions of the human alpha 1(VI) and alpha 2(VI) collagen genes is highly similar.

The alpha 1(VI) and alpha 2(VI) chains, two of the three constituent chains of type VI collagen, are highly similar in size and domain structure. They are encoded by single-copy genes residing in close proximity on human chromosome 21. To study the evolution of the type VI collagen genes, we have isolated and characterized genomic clones coding for the triple-helical domains of the human alpha 1(VI) and alpha 2(VI) chains, which consist of 336 and 335 amino acid residues, respectively. Nucleotide sequencing indicates that, in both genes, the exons are multiples of 9 bp in length (including 27, 36, 45, 54, 63, and 90 bp) except for those encoding for regions with triple-helical interruptions. In addition, the introns are positioned between complete codons. The most predominant exon size is 63 bp, instead of 54 bp as seen in the fibrillar collagen genes. Of particular interest is the finding that the exon structures of the alpha 1(VI) and alpha 2(VI) genes are almost identical. A significant deviation is that a segment of 30 amino acid residues is encoded by two exons of 54 and 36 bp in the alpha 1(VI) gene, but by a single exon of 90 bp in the alpha 2(VI) gene. The exon arrangement therefore provides further evidence that the two genes have evolved from tandem gene duplication. Furthermore, comparison with the previously reported gene structure of the chick alpha 2(VI) chain indicates that the exon structure for the triple-helical domain of the alpha 2(VI) collagen is strictly conserved between human and chicken.     

Specific antibodies to bovine choline acetyltransferase raised in mice immunised with small amounts of partially purified enzyme

Choline acetyltransferase was purified approximately 18,000-fold from 300 g of bovine caudate nuclei to a specific activity of 21 μmol min mg protein. The overall procedure used was: extraction of the enzyme by high salt concentration, chromatography on carboxy-methyl-Sephadex, precipitation by ammonium sulphate, affinity chromatography on Blue-Sepharose and, finally absorption on hydroxylapatite. When the enzyme absorbed on hydroxylapatite was injected into mice, it provoked reproducibly a transient production of ‘inhibitory’ antibodies, followed by higher antibody titres mainly of ‘non-inhibitory’ type. These responses were elicited by injecting less than a total of 20 μg of immunogen. The highest antibody titre was obtained less than 2 months following the initial immunisation. Species cross reactivity was investigated. This procedure should prove to be of value in the production of monoclonal antibodies to choline acetyltransferase.     

Thiamine and Cholinergic Transmission in the Electric Organ of Torpedo

The electric organ of Torpedo marmorata was found to contain as much as 120 +/- 24 nmol of thiamine per g of fresh tissue. The vitamin was distributed as nonesterified thiamine (32%), thiamine monophosphate (22%), thiamine diphosphate (8%), and an important proportion of thiamine triphosphate (38%). A high level of thiamine triphosphate was found in synaptosomes isolated from the electric organ. In contrast, the synaptic vesicles did not show any enrichment in thiamine, whereas they contained a marked peak of acetylcholine (ACh) and ATP. Thus thiamine seems to be very abundant in cholinergic nerve terminals; its localization is apparently extravesicular, either in the axoplasm or in association with plasma membrane. When calcium was reduced and magnesium increased in the external medium, the efficiency of transmission was diminished, owing to inhibition of ACh release; in a parallel manner the degree of thiamine phosphorylation was found to increase--this condition is known to modify the repartition of ACh between vesicular and extravesicular compartments. Electrical stimulation, which causes periodic variations of the level of ACh and ATP, also caused significant changes in thiamine esters. In addition, related changes of the vitamin and the transmitter were observed under other conditions, suggesting a functional link between the metabolism of thiamine and that of ACh in cholinergic nerve terminals.