A new restriction fragment length polymorphism in the haptoglobin gene region

Summary Direct gene analysis of the haptoglobin gene region was carried out by Southern blotting using an Hp cDNA as probe. Two types of polymorphism were observed: one due to intragenic duplication, is characterized by a constant fragment length difference of 1700bp observed with several enzymes and by complete correspondence with the protein molecular weight polymorphism; the second type, due to point mutation, was represented by two additional restriction sites for Eco RI and Pst I, with a frequency comparable to that of other genes. These two mutations segregated together in families, suggesting that the recently described Hp related gene is closely linked to the Hp gene. Moreover, they were completely associated with each other. The evolutionary significance of this finding is discussed.     

Molecular evidence of triplication in the haptoglobin Johnson variant gene

Summary The protein and gene structure of the Hp Johnson variant (Hp3) were analyzed in two related heterozygous individuals. The molecular weight (23kd) and amino acid composition of Hp3 alpha chain were in agreement with the triplicated structure first suggested by Smithies in 1964. Direct gene analysis by Southern blotting showed a three-fold tandem repeat of the same 1.7 kb DNA segment implicated in the Hp2 gene duplication. On the basis of these data a nine exon model for the Hp3 gene is proposed.     

Cloning, characterization, and modeling of a monoclonal anti-human transferrin antibody that competes with the transferrin receptor.

In this report we describe the isolation and characterization of a monoclonal antibody against human serum transferrin (Tf) and the cloning and sequencing of its cDNA. The antibody competes with the transferrin receptor (TR) for binding to human Tf and is therefore expected to bind at or very close to a region of interaction between Tf and its receptor. From the deduced amino acid sequence, we constructed a 3-dimensional model of the variable domains of the antibody based on the canonical structure model for the hypervariable loops. The proposed structure of the antibody is a first step toward a more detailed characterization of the antibody-Tf complex and possibly toward a better understanding of the Tf interaction with its receptor. The model might prove useful in guiding site-directed mutagenesis studies, simplifying the experimental elucidation of the antibody structure, and in the use of automatic procedures to dock the interacting molecules as soon as structural information about the structure of the human Tf molecule will be available.     

Prevention of Carbon Tetrachloride-Induced Lipid Peroxidation in Liver Microsomes from Dehydroepiandrosterone-Pretreated Rats

Dehydroepiandrosterone (DHEA), a lipid soluble steroid, administered to rats (100 mg/kg b.wt) by a single intraperitoneal injection, increases to twice its normal level in the liver microsomes. Microsomes so enriched become resistant to lipid peroxidation induced by incubation with carbon tetrachloride in the presence of a NADPH-regenerating system: also the lipid peroxidation-dependent inactivation of glucose-6-phosphatase and gamma-glutamyl transpetidase due to the haloalkane are prevented. Noteworthy, the liver microsomal drug-metabolizing enzymes and in particular the catalytic activity of cytochrome P₄₅₀IIE1, responsible for the CCl₄-activation, are not impaired by the supplementation with the steroid. Consistently, in DHEA-pretreated microsomes the protein covalent binding of the trichloromethyl radical (CCl₃°), is similar to that of not supplemented microsomes treated with CCl₄. It thus seems likely that DHEA protects liver microsomes from oxidative damage induced by carbon tetrachloride through its own antioxidant properties rather than inhibiting the metabolism of the toxin.     

Insertion mutations at the maizeOpaque2 locus induced by transposable element familiesAc, En/Spm andBg

Eight independently isolated unstable alleles of theOpaque2 (O2) locus were analysed genetically and at the DNA level. The whole series of mutations was isolated from a maize strain carrying a wild-typeO2 allele and the transposable elementActivator (Ac) at thewx-m7 allele. Previous work with another unstable allele of the same series has shown that it was indeed caused by the insertion of anAc element. Unexpectedly, the remaining eight mutations were not caused by the designatedAc element, but by other insertions that are structurally similar or identical to one of two different autonomous transposable elements. Six mutations were caused by the insertion of a transposable element of theEnhancer/Suppressor-Mutator (En/Spm) family. Two mutations were the result of the insertion of a transposable element of theBergamo (Bg) family. Genetic tests carried out with plants carrying the unstable mutations demonstrated that all were caused by the insertion of an autonomous transposable element.     

A long winter for the Red Queen: rethinking the evolution of seasonal migration

This paper advances an hypothesis that the primary adaptive driver of seasonal migration is maintenance of site fidelity to familiar breeding locations. We argue that seasonal migration is therefore principally an adaptation for geographic persistence when confronted with seasonality – analogous to hibernation, freeze tolerance, or other organismal adaptations to cyclically fluctuating environments. These ideas stand in contrast to traditional views that bird migration evolved as an adaptive dispersal strategy for exploiting new breeding areas and avoiding competitors. Our synthesis is supported by a large body of research on avian breeding biology that demonstrates the reproductive benefits of breeding‐site fidelity. Conceptualizing migration as an adaptation for persistence places new emphasis on understanding the evolutionary trade‐offs between migratory behaviour and other adaptations to fluctuating environments both within and across species. Seasonality‐induced departures from breeding areas, coupled with the reproductive benefits of maintaining breeding‐site fidelity, also provide a mechanism for explaining the evolution of migration that is agnostic to the geographic origin of migratory lineages (i.e. temperate or tropical). Thus, our framework reconciles much of the conflict in previous research on the historical biogeography of migratory species. Although migratory behaviour and geographic range change fluidly and rapidly in many populations, we argue that the loss of plasticity for migration via canalization is an overlooked aspect of the evolutionary dynamics of migration and helps explain the idiosyncratic distributions and migratory routes of long‐distance migrants. Our synthesis, which revolves around the insight that migratory organisms travel long distances simply to stay in the same place, provides a necessary evolutionary context for understanding historical biogeographic patterns in migratory lineages as well as the ecological dynamics of migratory connectivity between breeding and non‐breeding locations.     

Agrobacterium rhizogenes-mediated transformation of scented geranium

A method is described for producing genetically transformed plants from explants of three scentedPelargonium spp. Transgenic hairy root lines were developed fromPelargonium spp leaf explants and microcuttings after inoculation withAgrobacterium rhizogenes strains derived from the agropine A4 strain. Hairy root lines grew prolifically on growth regulator-free medium. Transgenic shoots were regenerated from hairy roots and the plants have been successfully transferred to soil. The phenotype of regenerated plants has been characterized as having abundant root development, more leaves and internodes than the controls, short internodes and highly branched roots and aerial parts. Southern blot analyses have confirmed the transgenic nature of these plants.     

Cyclic biphalin analogues with a novel linker lead to potent agonist activities at mu,delta, and kappa opioid receptors

In an effort to improve biphalin’s potency and efficacy at the µ-(MOR) and δ-opioid receptors (DOR), a series of cyclic biphalin analogues 1–5 with a cystamine or piperazine linker at the C-terminus were designed and synthesized by solution phase synthesis using Boc-chemistry. Interestingly, all of the analogues showed balanced opioid agonist activities at all opioid receptor subtypes due to enhanced κ-opioid receptor (KOR) activity. Our results indicate that C-terminal flexible linkers play an important role in KOR activity compared to that of the other cyclic biphalin analogues with a hydrazine linker. Among them, analogue 5 is a potent (Ki?=?0.27, 0.46, and 0.87?nM; EC₅₀?=?3.47, 1.45, and 13.5?nM at MOR, DOR, and KOR, respectively) opioid agonist with high efficacy. Based on the high potency and efficacy at the three opioid receptor subtypes, the ligand is expected to have a potential synergistic effect on relieving pain and further studies including in vivo tests are worthwhile.     

8,000 years of climate,vegetation, fire and land-use dynamics in the thermo-mediterranean vegetation belt of northern Sardinia (Italy)

Vegetation History and Archaeobotany - Knowledge about the vegetation history of Sardinia, the second largest island of the Mediterranean, is scanty. Here, we present a new sedimentary record...