Variability of the immunoglobulin heavy chain constant region locus: a population study

The Immunoglobulin Heavy chain Constant region (IGHC) locus is a multigene family composed of highly homologous segments often involved in unequal crossings over that lead to deleted and duplicated haplotypes. The frequencies of these haplotypes in 558 individuals from Lombardy, Veneto, Puglia and Sardinia were determined by Pulsed Field Gel Electrophoresis (PFGE), followed by Southern blotting with four IGHC probes, and compared with those observed in 110 subjects from Piedmont. Twenty deletions and 60 duplications were characterized, all in heterozygous individuals except for 2 homozygous deletions. The differences in frequency between the five populations were not significant. The deletions/duplications involved one or more genes: GP-A2, A1-E and G4 duplications, and A1-E and GP-A2 deletions were the most common. Four new duplications are described: three, involving the genes from GP to A2, from G2 to G4, and G4, are counterparts of known deletions. The fourth duplication spans from GP to G2. A G1 deleted heterozygous individual never previously described in Italy is reported. All the rearranged haplotypes seem to be the result of unequal crossing over. The difference between the number of duplications and deletions was significant in Sardinia, Lombardy, Puglia and in the total of 668 subjects (P < 0.001). This may be due to selection or genetic drift.     

New polymorphisms and markers in the HLA class I region: relevance to hereditary hemochromatosis (HFE)

Hereditary hemochromatosis (HFE) is an inherited disorder whose gene lies in the proximity of the histocompatability antigen (HLA) class I region, on 6p21.3. Despite efforts in refining the HFE region, a number of informative DNA markers, linked to the disease locus and amenable to use in an assay based on the polymerase chain reaction (PCR) is available. The gene content of this region is high, and the HFE gene has not so far been identified. We have used a strategy based on PCR protocols potentially able to detect both polymorphisms and expressed sequences. This approach has been applied to a 700-kb stretch (approximately) of DNA corresponding to the insert of a Centre d'Etude du Polymorphisme Humain yeast artificial chromosome (225 B1) of the possible candidate region. Five new polymorphisms have been detected among 20 specific fragments isolated. Four of them are tightly linked to the HFE locus. Because of the strong linkage disequilibrium with the disease demonstrated by these markers, they could represent starting points for the identification and characterization of the HFE gene. The remaining non-polymorphic fragments, being amplifiable and in most cases linked to NotI sites, may be useful starting points for the generation of a genomic contig of band 6p21.3 and for gene identification.     

Sugar-binding activity of pea (Pisum sativum) lectin is essential for heterologous infection of transgenic white clover hairy roots by Rhizobium leguminosarum biovar viciae

Legume lectin stimulates infection of roots in the symbiosis between leguminous plants and bacteria of the genus Rhizobium. Introduction of the Pisum sativum lectin gene (psl) into white clover hairy roots enables heterologous infection and nodulation by the pea symbiont R. leguminosarum biovar viciae (R.l. viciae). Legume lectins contain a specific sugar-binding site. Here, we show that inoculation of white clover hairy roots co-transformed with a psl mutant encoding a non-sugar-binding lectin (PSL N125D) with R.l. viciae yielded only background pseudo-nodule formation, in contrast to the situation after transformation with wild type psl or with a psl mutant encoding sugar-binding PSL (PSL A126V). For every construct tested, nodulation by the homologous symbiont R.l. trifolii was normal. These results strongly suggest that (1) sugar-binding activity of PSL is necessary for infection of white clover hairy roots by R.l. viciae, and (2) the rhizobial ligand of host lectin is a sugar residue rather than a lipid.     

Somatic embryogenesis from chickpea (Cicer arietinum L.) inmature cotyledons: The effect of zeatin, gibberellic acid and indole-3-butyric acid

Studies were conduced to test the effects of various cytokinins on somatic embryogenesis from chickpea (Cicer arietinum L.) immature cotyledons. Zeatin (13.7 μmol) added, to B5 basal medium, supplemented with 1.5 % sucrose and 0.2 μmol indole-3-acetic acid, was the most effective cytokinin. Lobular structures obtained from cotyledons cultures were transferred to B5 basal medium supplemented with gibberellic acid and indole-3-butyric acid at different concentrations. The most effective treatment was B5 medium containing 14.4 μmol gibberellic acid plus 1.0 μmol indole-3-butyric acid in which 42.8 % of lobular structures cultured formed normal somatic embryos. High conversion of embryos into plantlets (61.0–65.2 % embryos regenerated plants) was observed when germinated embryos were placed on plant development medium.     

Genetic transformation with thesulI gene; a highly efficient selectable marker forSolanum tuberosum L. cv. ‘Russet Burbank’

Selection of transformed plants is a fundamental requirement for plant molecular breeding. We have developed the use of thesulI gene, whose application has already been described in tobacco [17] for selection in the important potato cultivar Russet Burbank. We found that theSulI marker is highly effective, with efficiency comparable to that ofnptII. Analysis of the effect of thesulI gene on folate metabolism in Russet Burbank under sulfa drug selection demonstrates thatsulI may be an important tool for analysis of folate metabolism in plants.     

SRY-negative true hermaphrodites and an XX male in two generations of the same family

Two 46,XX true hermaphrodites and one XX male without genital ambiguities are reported. They coexist in two generations of the same pedigree, with paternal transmission and in the absence of SRY (sex-determining region, Y chromosome). These familial cases provide evidence to support the hypothesis that these disorders are alternative manifestations of the same genetic defect, probably an autosomal dominant mutation (with incomplete penetrance) or an X-linked mutation (limited by the presence of the Y chromosome).     

Preliminary results in HIV-1-infected patients treated with transfer factor (TF) and Zidovudine (ZDV)

The efficiency of HIV-1 specific transfer factor (TF) administration, combined with Zidovudine (ZDV), in asymptomatic persistent generalised lymphadenopaty, or AIDS related complex (ARC) patients was evaluated. Twenty patients were randomly assigned to receive only ZDV (1st group) or ZDV together with HIV-1-specific TF (2nd group). HIV-1-specific TF was administered orally at 2 × 10⁷ cell equivalent daily for 15 days, and thereafter once a week for up to 6 months. There were no significant differences between the two groups in clinical evolution, red blood cells, haemoglobin, lymphocytes, CD20 subset, transaminases,β-2-microglobulin, p24 antigen. White blood cells, CD8 lymphocytes as well as IL-2 levels increased in the second group, while the CD4 subset increased in the first group. The combination treatment with ZDV and TF appeared to be safe and well tolerated. Furthermore, levels of serum cytokines were investigated in 10 patients (8 asymptomatic and 2 ARC) treated with ZDV, and compared with 5 patients of the 2nd group (3 asymptomatic and 2 ARC) treated with ZDV plus HIV-1-specific TF. Peripheral lymphocytes, CD4, CD8 subsets, IL-2, TNFα, IL-6, p24 antigen, IL-2 soluble lymphocyte receptors (sR), CD4sR, CD8sR and ß-2-microglobulin were evaluated at the baseline and at the 3rd month. The CD4 subset was not significantly different in the two groups, whilst IL-2 increased in the 2nd group receiving ZDV plus TF, suggesting an activation of the Th1 secretion pattern.     

Hexose keto-C-glycoside conjugates: design, synthesis, cytotoxicity, and evaluation of their affinity for the glucose transporter glut-1

The design, synthesis, cytotoxicity, and biological evaluation of carbohydrate/C-glycoside conjugates are described. The design concept is predicted on the idea that physiological barriers like the blood brain barrier could be crossed selectively by using glucose or glucose derivative/drug conjugates. The study demonstrates that, (1) carbohydrates and C-glycosides can be bonded at nonanomeric positions by the reaction of carbohydrate triflates with C-glycoside alkoxydes in the presence of DMPU; (2) there is a structure-activity relationship between the cytotoxicity of the conjugate and the nature of the carbohydrate residue; and (3) peracetylated hexose keto-C-glycoside conjugates are the most cytotoxic keto-C-glycosides.     

Somatic embryogenesis inGnetum ula Brongn. (Gnetum edule) (Willd) Blume

Summary Somatic embryos ofGnetum ula (Gnetum edule) an endangered gymnosperm closely related to the angiosperms have been induced in vitro. Megagametophyte tissue with immature embryos was cultured on Murashige and Skoog medium. A mucilaginous, translucent embryogenic callus was obtained with 5 mg/l BA. Callus induced with 2,4-D was non-embryogenic. The embryogenic callus in liquid half strength Murashige and Skoog medium without inorganic nitrates supplemented with 2.5 g/l casein hydrolysate and 0.5 g/l L-glutamine gave rise to immature embryos. The embryos matured when treated with 60 g/l sucrose and 10 mg/l abscisic acid.Abbreviations MS Murashige and Skoog - BA 6-benzylaminopurine - 2,4-D 2,4 - dichlorophenoxyacetic acid - ABA abscisic acid     

Information on Resource Quality Mediates Aggression between Male Madagascar Hissing Cockroaches, Gromphadorhina portentosa (Dictyoptera: Blaberidae)

Male Madagascar hissing cockroaches, Gromphadorhina portentosa Schaum (Dictyoptera: Blaberidae) have a well‐defined dominance hierarchy that has been assumed to explain the outcome of most competitive interactions. We studied whether males of this species would alter their level of aggression towards unfamiliar rivals as a function of changing resource availability and value – two factors that are key to aggression levels in non‐hierarchical species. We quantified male aggression as three variables (aggressive state – behaviours measured by their duration; aggressive act – behaviours measured by their frequency of occurrence; aggressive latency – the latency to first aggressive behaviour, either state or act) and tested for any context‐specific variation within each by manipulating both territorial status (males were either residents or intruders) and access to mates (female present or absent). Both the presence of a female and territorial status affected male aggression towards rivals as measured by duration of aggressive state. Highest levels of aggression were displayed by residents when a female was present. These results show that inter‐male aggression in G. portentosa is tuned to the immediate expected payoff from fighting, and not exclusively aimed at establishing dominance relationships (which can affect future payoffs).