Genetic diversity of durum wheat as determined by AFLP in fluorescence

The DNA of fifteen Italian cultivars of durum wheat (Triticum turgidum L. ssp. durum) were analyzed by in fluorescence amplified fragment length polymorphism (fAFLP) in order to obtain the characteristic fingerprintings of genotypes and assess their genetic relatedness. Among 64 combinations of fluorescence labelled primers, three different combinations were chosen as producing a total of 6630 AFLP fragments, 2277 (34.3 %) of them being polymorphic. By using this fAFLP methodology a DNA fingerprinting of each durum wheat cultivar was generated for genotype identification. Analysis of the genetic relationships show the low variability among durum wheat cultivars.     

Effect of acetyl-l-carnitine on lipid peroxidation and xanthine oxidase activity in rat skeletal muscle

It has been reported that acetyl-l-carnitine (AcCn) can reduce the degenerative processes in the central nervous system of rats, modify the fluidity of membranes and decrease the accumulation of lipofuscins in neurones. In light of these considerations we have assayed the in vitro effect of acetyl-l-carnitine on spontaneous and induced lipoperoxidation in rat skeletal muscle; in addition, the effect of AcCn on XD/XO ratio was evaluated. The presence of AcCn (10–40 mM) in incubation medium significantly reduced MDA and conjugated diene formation in rat skeletal muscle; moreover, a significant decrease in induced MDA levels was observed when microsomal preparation where incubated in the presence of 10–40 mM AcCn. Since a significant reduction of XO activity was detected in the presence of 10–80 mM AcCn, the reduced lipid peroxidation by AcCn seems to be due to an inhibition of XO activity.     

Relative burden of large CNVs on a range of neurodevelopmental phenotypes

While numerous studies have implicated copy number variants (CNVs) in a range of neurological phenotypes, the impact relative to disease severity has been difficult to ascertain due to small sample sizes, lack of phenotypic details, and heterogeneity in platforms used for discovery. Using a customized microarray enriched for genomic hotspots, we assayed for large CNVs among 1,227 individuals with various neurological deficits including dyslexia (376), sporadic autism (350), and intellectual disability (ID) (501), as well as 337 controls. We show that the frequency of large CNVs (>1 Mbp) is significantly greater for ID-associated phenotypes compared to autism (p = 9.58 × 10(-11), odds ratio = 4.59), dyslexia (p = 3.81 × 10(-18), odds ratio = 14.45), or controls (p = 2.75 × 10(-17), odds ratio = 13.71). There is a striking difference in the frequency of rare CNVs (>50 kbp) in autism (10%, p = 2.4 × 10(-6), odds ratio = 6) or ID (16%, p = 3.55 × 10(-12), odds ratio = 10) compared to dyslexia (2%) with essentially no difference in large CNV burden among dyslexia patients compared to controls. Rare CNVs were more likely to arise de novo (64%) in ID when compared to autism (40%) or dyslexia (0%). We observed a significantly increased large CNV burden in individuals with ID and multiple congenital anomalies (MCA) compared to ID alone (p = 0.001, odds ratio = 2.54). Our data suggest that large CNV burden positively correlates with the severity of childhood disability: ID with MCA being most severely affected and dyslexics being indistinguishable from controls. When autism without ID was considered separately, the increase in CNV burden was modest compared to controls (p = 0.07, odds ratio = 2.33).     

Nesaecrepida infuscata: a biological control agent of the invasive plant Mimosa pigra

Mimosa pigra L. is a serious weed of wetlands of Australia, Asia and Africa. A suite of established biocontrol agents have been introduced in Australia and some Asian countries, but better control is needed. Nesaecrepida infuscata (Schaeffer) (Coleoptera: Chrysomelidae) is a common insect on M. pigra in tropical America. The larvae develop on the roots while the adults feed on the leaves. As both roots and leaves of M. pigra are relatively undamaged in the introduced range, this species has potential to limit the growth, survival and seed production. Furthermore, it is abundant in the dry season and so inflicts damage when most other agents are not active. In host specificity tests, larvae did not develop on any of the 65 test plant species other than M. pigra. Adult feeding on test plant species other than M. pigra was minimal. Based on these results, this insect has been released in Australia.     

Molecular basis of α-thalassemia in Sicily

To evaluate the allelic frequency and genetic diversity of α-thalassemia defects in Sicily, both epidemiological and patient-oriented studies were carried out. For the epidemiological study, phenotypic data were collected on more than 1000 Sicilian individuals. Among them, 427 were explored at the molecular level for nine α-thalassemic variants known to be common in the Mediterranean region. Our data reveal an allele frequency of 4.1% for α⁺-thalassemia matching that of β-thalassemia in this region. The presence of α°-thalassemia (––^MEDI and ––^CAL) was observed only in the group of referred patients. Newly acquired nucleotide sequence data on the deletional breakpoint of ––^CAL allowed us to design a simple PCR-based procedure for exploring this allele. The data also provide additional information concerning the genetic mechanisms involved in such large deletions. Received: 8 August 1996 / Revised: 16 October 1996     

Genetic variations in human fetal globin gene microsatellites and their functional relevance

Short tandem repeats are abundantly present within the genome. They are commonly used as polymorphic markers but their potential functional role is poorly documented. Several of these microsatellites have been described within the β-globin locus and some could be involved in controlling gene expression. Our purpose was to investigate the extent and significance of the (TG)n(CG)m dinucleotide repeat polymorphisms in the two γ-globin gene IVS2s. Two groups of subjects were studied: a group of 63 β-thalassaemic patients presenting either with a severe Cooley’s anaemia (n = 50) or with thalassaemia intermedia (TI, n = 13), and a control group of 60 unrelated healthy individuals. A high heterogeneity of the polymorphic repeats was demonstrated, extending the range of the published alleles from 13 to 22 and allowing a first attempt at making a phenotype/genotype correlation. One specific allele, (TG)₁₃ in the Aγ-gene, was highly enriched in the TI patients (46.1% vs 2.9% of the Cooley’s anaemia cases, P < 0.0002, and 23.3% in the normal controls, P < 0.008) and preferentially observed in TI patients with a high haemoglobin F (Hb F). Transient transfection assays in K562 cells, with the growth hormone gene as a reporter, showed a positive regulatory action mediated by a (TG)₁₃-containing 243 nt IVS2 fragment. Finally, a first set of mobility shift experiments with erythroid (K562 and MEL) and nonerythroid (HeLa) cell lines showed binding of erythroid component(s) in this DNA region and the binding pattern was modified upon induction of MEL cells by DMSO. Thus, our in vivo and in vitro data raise the question of a possible contribution of the γ-gene IVS2s polymorphic microsatellites to the variable Hb F synthesis in the major haemoglobinopathies: a well known, puzzling and still unanswered question. Received: 22 April 1998 / Accepted: 15 December 1998     

Trypanosoma cruzi-specific immune responses in subjects from endemic areas of Chagas disease of Argentina

Trypanosoma cruzi-specific immune responses were evaluated in a total of 88 subjects living in areas endemic of Chagas disease of Argentina by IFN-γ ELISPOT assays and immunoblotting. Positive T. cruzi antigen-induced IFN-γ responses were detected in 42% of subjects evaluated (15/26 positive by conventional serology and 22/62 seronegative subjects). Using immunoblotting, T. cruzi-specific IgG reactivity was detected in all seropositive subjects and in 11% (7/61) of subjects negative by conventional serology. Measurements of T cell responses and antibodies by immunoblotting, in conjunction with conventional serology, might enhance the capability of detection of exposure to T. cruzi in endemic areas.