Photochemical UV/TiO2 treatment of olive mill wastewater (OMW)

Olive mill wastewater (OMW) was treated by photocatalysis using TiO2 under UV irradiation on the laboratory scale. The chemical oxygen demand, the coloration at 330nm, and the level of phenols all showed decreases which, after a 24-h treatment, reached 22%, 57% and 94%, respectively. The differences between these three values indicate the persistence of colourless, non-phenolic compounds. Application of the novel Fictitious Atomic-Group Separation method showed an increase in carbon oxidation state and confirmed that the attack primarily concerns, aromatic moieties. A fine spectroscopic study revealed the occurrence of three successive phases during the degradation process, thought to correspond to three different categories of molecules in the OMW and the presence of pectin compounds.     

TCTP protects from apoptotic cell death by antagonizing bax function

Translationally controlled tumor protein (TCTP) is a potential target for cancer therapy. It functions as a growth regulating protein implicated in the TSC1-TSC2 -mTOR pathway or a guanine nucleotide dissociation inhibitor for the elongation factors EF1A and EF1Bbeta. Accumulating evidence indicates that TCTP also functions as an antiapoptotic protein, through a hitherto unknown mechanism. In keeping with this, we show here that loss of tctp expression in mice leads to increased spontaneous apoptosis during embryogenesis and causes lethality between E6.5 and E9.5. To gain further mechanistic insights into this apoptotic function, we solved and refined the crystal structure of human TCTP at 2.0 A resolution. We found a structural similarity between the H2-H3 helices of TCTP and the H5-H6 helices of Bax, which have been previously implicated in regulating the mitochondrial membrane permeability during apoptosis. By site-directed mutagenesis we establish the relevance of the H2-H3 helices in TCTP's antiapoptotic function. Finally, we show that TCTP antagonizes apoptosis by inserting into the mitochondrial membrane and inhibiting Bax dimerization. Together, these data therefore further confirm the antiapoptotic role of TCTP in vivo and provide new mechanistic insights into this key function of TCTP.     

Evolutionary history of Trypanosoma cruzi according to antigen genes

Trypanosoma cruzi, the agent of Chagas disease is associated with a very high clinical and epidemiological pleomorphism. This might be better understood through studies on the evolutionary history of the parasite. We explored here the value of antigen genes for the understanding of the evolution within T. cruzi. We selected 11 genes and 12 loci associated with different functions and considered to be involved in host-parasite interaction (cell adhesion, infection, molecular mimicry). The polymorphism of the respective genes in a sample representative of the diversity of T. cruzi was screened by PCR-RFLP and evolutionary relationships were inferred by phenetic analysis. Our results support the classification of T. cruzi in 2 major lineages and 6 discrete typing units (DTUs). The topology of the PCR-RFLP tree was the one that better fitted with the epidemiological features of the different DTUs: (i) lineage I, being encountered in sylvatic as well as domestic transmission cycles, (ii) IIa/c being associated with a sylvatic transmission cycle and (iii) IIb/d/e being associated with a domestic transmission cycle. Our study also supported the hypothesis that the evolutionary history of T. cruzi has been shaped by a series of hybridization events in the framework of a predominant clonal evolution pattern.     

Evaluation of an in vitro and in vivo model for experimental infection with Leishmania (Viannia) braziliensis and L. (V.) peruviana

Leishmania (Viannia) braziliensis and L. (V.) peruviana are two parasite species characterized by a very different pathogenicity in humans despite a high genetic similarity. We hypothesized previously that L. (V.) peruviana would descend from L. (V.) braziliensis and would have acquired its 'peruviana' character during the southward colonization and adaptation of the transmission cycle in the Peruvian Andes. In order to have a first appreciation of the differences in virulence between both species, we evaluated an in vitro and in vivo model for experimental infection. A procedure was adapted to enrich culture forms in infective stages and the purified metacyclics were used to infect macrophage cell lines and golden hamsters. The models were tested with 2 representative strains of L. (V.) braziliensis from cutaneous and mucosal origin respectively and 2 representative strains of L. (V.) peruviana from Northern and Southern Peru respectively. Our models were reproducible and sensitive enough to detect phenotypic differences among strains. We showed in vitro as well as in vivo that the L. (V.) braziliensis was more infective than L. (V.) peruviana. Furthermore, we found that in vitro infectivity patterns of the 4 strains analysed, were in agreement with the geographical structuring of parasite populations demonstrated in our previous studies. Further work is needed to confirm our results with more strains of different geographical origin and their specific clinical outcome. However, our data open new perspectives for understanding the process of speciation in Leishmania and its implications in terms of pathogenicity.     

Phylogeographic evidence of crop neodiversity in sorghum

Sorghum has shown the adaptability necessary to sustain its improvement during time and geographical extension despite a genetic foundation constricted by domestication bottlenecks. Initially domesticated in the northeastern part of sub-Saharan Africa several millenia ago, sorghum quickly spread throughout Africa, and to Asia. We performed phylogeographic analysis of sequence diversity for six candidate genes for grain quality (Shrunken2, Brittle2, Soluble starch synthaseI, Waxy, Amylose extender1, and Opaque2) in a representative sample of sorghum cultivars. Haplotypes along 1-kb segments appeared little affected by recombination. Sequence similarity enabled clustering of closely related alleles and discrimination of two or three distantly related groups depending on the gene. This scheme indicated that sorghum domestication involved structured founder populations, while confirming a specific status for the guinea margaritiferum subrace. Allele rooted genealogy revealed derivation relationships by mutation or, less frequently, by recombination. Comparison of germplasm compartments revealed contrasts between genes. Sh2, Bt2, and SssI displayed a loss of diversity outside the area of origin of sorghum, whereas O2 and, to some extent, Wx and Ae1 displayed novel variation, derived from postdomestication mutations. These are likely to have been conserved under the effect of human selection, thus releasing valuable neodiversity whose extent will influence germplasm management strategies.     

Mapping Human Telomere Regions with YAC and P1 Clones: Chromosome-Specific Markers for 27 Telomeres Including 149 STSs and 24 Polymorphisms for 14 Proterminal Regions

A YAC library enriched for telomere clones was constructed and screened for the human telomere-specific repeat sequence (TTAGGG). Altogether 196 TYAC library clones were studied: 189 new TYAC clones were isolated, 149 STSs were developed for 132 different TYACs, and 39 P1 clones were identified using 19 STSs from 16 of the TYACs. A combination of mapping methods including fluorescencein situhybridization, somatic cell hybrid panels, clamped homogeneous electric fields, meiotic linkage, and BLASTN sequence analysis was utilized to characterize the resource. Forty-five of the TYACs map to 31 specific telomere regions. Twenty-four linkage markers were developed and mapped within 14 proterminal regions (12 telomeres and 2 terminal bands). The polymorphic markers include 12 microsatellites for 10 telomeres (1q, 2p, 6q, 7q, 10p, 10q, 13q, 14q, 18p, 22q) and the terminal bands of 11q and 12p. Twelve RFLP markers were identified and meiotically mapped to the telomeres of 2q, 7q, 8p, and 14q. Chromosome-specific STSs for 27 telomeres were identified from the 196 TYACs. More than 30,000 nucleotides derived from the TYAC vector-insert junction regions or from regions flanking TYAC microsatellites were compared to reported sequences using BLASTN. In addition to identifying homology with previously reported telomere sequences and human repeat elements, gene sequences and a number of ESTs were found to be highly homologous to the TYAC sequences. These genes include human coagulation factor V (F5), Wee1 protein tyrosine kinase (WEE1), neurotropic protein tyrosine kinase type 2 (NTRK2), glutathioneS-transferase (GST1), and β tubulin (TUBB). The TYAC/P1 resource, derivative STSs, and polymorphisms constitute an enabling resource to further studies of telomere structure and function and a means for physical and genetic map integration and closure.     

Intralesional injection of immunostimulants in rat and mouse tumors

Summary To study the mechanism of the therapeutic effect of intratumoral injection of immunostimulants in tumors, an experimental model was designed. This model includes six rat tumors and six mouse tumors which can be compared for different parameters: susceptibility or resistance to various immunostimulants injected intralesionally, histological characteristics, and immunogeneicity. This complex model is described in the present paper.Fellow of the Association en faveur du Développement de la Recherche sur le Cancer à Villejuif     

Virus content of leaves of cassava infected by African cassava mosaic virus

African cassava mosaic virus (ACMV) was detected in cassava leaves by ELISA. Some normal constituents of cassava leaves interfered with virus detection but leaf extracts of Nicotiana benthamiana did not. The symptom pattern was determined early in the growth of a leaf and subsequently changed little. ACMV was found only in the yellow or yellow green areas of the mosaic pattern. Virus content of the leaves increased with increasing symptom intensity, but decreased with leaf age and ACMV was not detected in mature leaves. Most whiteflies were found on young growing cassava leaves and the number decreased progressively with leaf age. This distribution will aid both the acquisition and inoculation of the virus.     

Nucleic acid and prion protein interaction produces spherical amyloids which can function in vivo as coats of spongiform encephalopathy agent

The infectious agent of transmissible spongiform encephalopathies (TSE) has been considered to be PrP(SC), a structural isoform of cellular prion protein PrP(C). PrP(SC) can exist as oligomers and/or as amyloid polymers. Nucleic acids induce structural conversion of recombinant prion protein PrP and PrP(C) to PrP(SC) form in solution and in vitro. Here, we report that nucleic acids, by interacting with PrP in solution, produce amyloid fibril and fibres of different morphologies, similar to those identified in the diseased brains. In addition, the same interaction produces polymer lattices and spherical amyloids of different dimensions (15-150 nm in diameters). The polymer lattices show apparent morphological similarity to the two-dimensional amyloid crystals obtained from linear amyloids isolated in vivo. The spherical amyloids structurally resemble "spherical particles" observed in natural spongiform encephalopathy (SE) and in scrapie-infected brains (TSE). We suggest that spherical amyloids, PrP(SC)-amylospheroids, are probable constituents of the coat of the spherical particles found in vivo and the latter can act as protective coats of the SE and TSE agents in vivo.