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A reactive rotational molding (RRM) process was developed to obtain a PA6 by activated anionic ring-opening polymerization of epsilon-caprolactam (APA6). Sodium caprolactamate (C10) and caprolactam magnesium bromide (C1) were employed as catalysts, and difunctional hexamethylene-1,6-dicarbamoylcaprolactam (C20) was used as an activator. The kinetics of the anionic polymerization of !-caprolactam into polyamide 6 was monitored through dynamic rheology and differential scanning calorimetry measurements. The effect of the processing parameters, such as the polymerization temperature, different catalyst/activator combinations and concentrations, on the kinetics of polymerization is discussed. A temperature of 150°C was demonstrated to be the most appropriate. It was also found that crystallization may occur during PA6 polymerization and that the combination C1/C20 was well suited as it permitted a suitable induction time. Isoviscosity curves were drawn in order to determine the available processing window for RRM. The properties of the obtained APA6 were compared with those of a conventionally rotomolded PA6. Results pointed at lower cycle times and increased tensile properties at weak deformation.

The objective of the present study was to investigate multiphase systems based on polylactic acid (PLA) and polyamide 11 (PA11) from blends to multilayers. Firstly, PLA/PA11 blends compatibilized with a multifunctionalized epoxide, Joncryl, were obtained through reactive extrusion, and the thermal, morphological, rheological, and mechanical behaviors of these materials were investigated. The role of Joncryl as a compatibilizer for the PLA/PA11 system was demonstrated by the significant decrease in particle size and interfacial tension as well as by the tensile properties exhibiting a ductile behavior. Based on these findings, we were able to further clarify the effects of interdiffusion and diffuse interphase formation on the structure, rheology, and mechanics of compatible multilayered systems fabricated with forced-assembly multilayer coextrusion. The results presented herein aim to provide a deeper understanding of the interfacial properties, including the rheological, mechanical, and morphological behaviors, towards the control of the interface and confinement in multilayer polymers resulting from coextrusion, and also to permit their use in advanced applications.

In the present study, the recycled post-consumption polyethylene terephthalate (PET) flakes were investigated as possible raw materials for the production of food packaging. After heating at 220 °C for 1 h, a steaming stage was conducted as a control test to assess the quality of the product. Different samples were characterized by 1 H-NMR, FT-IR, DSC/TGA analysis, viscosity index (VI), and trace metals analysis. The results showed that the recycled post-consumed PET flakes' properties were generally conform to the standard norms of PET except the color of some flakes turned to yellow. Subsequently, a complementary study was undertaken to assess whether the material could be possibly reused for food packaging. For this purpose, rheological, thermal, and mechanical characterizations were performed. The results of the comparative study between the virgin and the recycled PET flakes concluded that the PET recycling affected the rheological properties but did not have any significant effect on their thermal and mechanical characteristics. Hence, it was deduced that the post-consumed PET flakes could be reused as a packaging material except food products.

The plastic materials used for packaging are increasing leading to a considerable amount of undegradable solid wastes. This work deals with the reduction of conventional plastics waste and the natural resources preservation by using cellulosic polymers from renewable resources (alfa and luffa). Plasticized starch films syntheses were achieved at a laboratory scale. These natural films showed some very attractive mechanical properties at relatively low plasticizers levels (12 to 17 % by weight). Furthermore, mixtures including polylactic acid polymer (PLA) and cellulose fibers extracted from alfa and luffa were investigated by melt extrusion technique. When used at a rate of 10 %, these fibers improved the mixture mechanical properties. Both developed materials were biodegradable, but the plasticized starch exhibited a faster biodegradation kinetic compared to the PLA/cellulose fibers. These new materials would contribute to a sustainable development and a waste reduction.

The objective of this study was to gain a deep understanding of composition and compatibilization effects on the properties of entirely sustainably sourced polymer blends based on polylactide (PLA) and polyamide 11 (PA11). Generally, PLA cannot challenge regular commodity polymers due to its weak thermo-mechanical properties and its poor elongation properties. With this work, however, we present a promising route to overcome these drawbacks in order to enhance the processability of PLA: blending the polymer with various compositions of other ductile biopolymers such as PA11, as well as mixing PLA/PA11 blends with various amounts of a chain extender, Joncryl ADR ® -4368, containing reactive epoxy functions, in a laboratory-scale twin-screw extruder. The effects on the rheological, morphological and mechanical properties were investigated. Results showed that a "self compatibilization" between PLA and PA11 chains can occur but it was found to be insufficient, contrary to recent work reported in the literature. The role of Joncryl as a compatibilizer for the PLA/PA11 system has been demonstrated by the significant decrease of particle size and interfacial tension as well as the improvement of ductile properties. Moreover, a new relaxation peak appeared in the relaxation spectrum, indicating the generation of a copolymer at the polymer-polymer interface.

The phytopathogenic bacterium Rhodococcus fascians provokes shoot meristem formation and malformations on aerial plant parts, mainly at the axils. The interaction is accompanied by bacterial colonization of the plant surface and tissues. Upon infection, the two bacterial loci required for full virulence, fas and att, were expressed only at the sites of symptom development, although their expression profiles differed both spatially and temporally. The att locus was expressed principally in bacteria located on the plant surface at early stages of infection. Expression of the fas locus occurred throughout infection, mainly in bacteria that were penetrating, or had penetrated, the plant tissues and coincided with sites of meristem initiation and proliferation. The implications for the regulation of virulence genes of R. fascians during plant infection are discussed.

The application of immunoaffinity chromatography for the purification of Taxus plant and cell extracts prior to the HPLC analysis is described. Polyclonal antibodies raised against 10-deacetylbaccatin III (10-DAB III), paclitaxel's main precursor in plant, were characterised by enzymed-linked immunosorbent assay. Immunoglobulins from selected antisera were immobilised on CNBr-activated Sepharose 4B. The immunoaffinity column was used for the purification of plant and plant cell culture extracts prior to their analysis by HPLC. Immunoaffinity chromatography enabled the selective concentration of taxoids and enhanced sample clean-up.

The gram-positive plant pathogen Rhodococcus fascians provokes leafy gall formation on a wide range of plants through secretion of signal molecules that interfere with the hormone balance of the host. Crucial virulence genes are located on a linear plasmid, and their expression is tightly controlled. A mutant with a mutation in a chromosomal locus that affected virulence was isolated. The mutation was located in gene vicA, which encodes a malate synthase and is functional in the glyoxylate shunt of the Krebs cycle. VicA is required for efficient in planta growth in symptomatic, but not in normal, plant tissue, indicating that the metabolic requirement of the bacteria or the nutritional environment in plants or both change during the interaction. We propose that induced hyperplasia on plants represents specific niches for the causative organisms as a result of physiological alterations in the symptomatic tissue. Hence, such interaction could be referred to as metabolic habitat modification.

Diterpenic alkaloids belonging to taxine (yield: 0.18 % dry weight) and taxoids (paclitaxel, baccatine III and 10-deacetylbaccatine III, cumulated yield: 0.004 % dry weight) were isolated from Taxus baccata L. pollen. Moreover, taxoids conjugated to macromolecules were also detected by ELISA. According to these data and to semi-quantitative measurements of pollen production, a hundred-year-old yew during its flowering time releases several grams of taxanes contained in 16 to 20 kg of pollen. Toxicity assays on mice indicated that any risk of acute toxicity resulting from Taxus pollen inhalation and subsequent taxine absorption is unlikely. On the other hand, anti-paclitaxel IgG were above all detected in sera of subjects displaying hypersensitivity reactions during the pollination periods of Taxus sp. and Betula sp. This natural anti-paclitaxel IgG acquisition by individuals living in the distribution areas of these trees could be at the origin of atopic manifestations. We also postulate that such a natural sensitization could have a marked influence on the tolerance to anticancer taxoids.

Rhodococcus fascians is a plant-pathogenic bacterium that causes malformations on aerial plant parts, whereby leafy galls occur at axillary meristems. The colonization behavior on Nicotiana tabacum and Arabidopsis thaliana plants was examined. Independent of the infection methods, R. fascians extensively colonized the plant surface where the bacteria were surrounded by a slime layer. R. fascians caused the collapse of epidermal cells and penetrated intercellularly into the plant tissues. The onset of symptom development preceded the extensive colonization of the interior. The meristematic regions induced by pathogenic strain D188 were surrounded by bacteria. The nonpathogenic strain, D188-5, colonized the exterior of the plant equally well, but the linear plasmid (pFiD188) seemed to be involved in the penetration efficiency and colonization of tobacco tissues.

Rhodococcus fascians infects a wide range of plants, initiating the formation of leafy galls that consist of centers of shoot amplification and shoot growth inhibition. R. fascians is an epiphyte but it also can establish endophytic populations. Bacterial signals involved in symptom development initiate de novo cell division and shoot meristem formation in differentiated tissues. The R. fascians signals exert activities that are distinct from mere cytokinin effects, and the evidence points to a process that adopted cytokinin biosynthetic enzymes to form derivatives with unique activity. Genes implicated in leafy gall formation are located on a linear plasmid and are subject to a highly controlling, complex regulatory network, integrating autoregulatory compounds and environmental signals. Leafy galls are considered as centers with specific metabolic features, a niche where populations of R. fascians experience a selective advantage. Such "metabolic habitat modification" might be universal for gall-inducing bacteria.

Rhodococcus fascians is a Gram-positive bacterium that infects dicotyledonous and monocotyledonous plants, leading to an alteration in the normal growth process of the host. The disease results from the modulation of the plant hormone balances, and cytokinins are thought to play an important role in the induction of symptoms. Generally, on the aerial parts of the plants, existing meristems were found to be most sensitive to the action of R. fascians, but, depending on the infection procedure, differentiated tissues as well gave rise to shoots. Similarly, in roots not only actively dividing cells, but also cells with a high competence to divide were strongly affected by R. fascians. The observed symptoms, together with the determined hormone levels in infected plant tissue, suggest that auxins and molecules of bacterial origin are also involved in leafy gall formation. The complexity of symptom development is furthermore illustrated by the necessary and continuous presence of the bacteria for symptom persistence. Indeed, elimination of the bacteria from a leafy gall results in the further development of the multiple embryonic buds of which it consists. This interesting characteristic offers novel biotechnological applications: a leafy gall can be used for germplasm storage and for plant propagation. The presented procedure proves to be routinely applicable to a very wide range of plants, encompassing several recalcitrant species.

Two new taxoids, 13-deoxo-13 alpha-acetyloxy-7 beta,9 alpha-diacetyl-1,2-dideoxytaxine B[1] and 7 beta-xylosyl-10-deacetyltaxol D [7], were isolated from the stem bark of Taxus baccata cv. stricta. Their structures were elucidated using spectroscopic methods and their bioactivity was evaluated using an in vitro microtubule assembly assay.

Callus cultures of Taxus baccata L. cv. stricta were induced from hypocotyl and leaf explants on Woody Plant medium (hormone-free or additionated with phytohormones). Under continuous dark condition, adventitious roots were regenerated from hypocotyl- and leaf-derived callus cultures. Antibodies raised in rabbits against 10-succinyl-10-deacetylbaccatin III were used for the detection and the semi-quantitative determination of 10-deacetylbaccatin III in Taxus cultures. The presence of 10-deacetylbaccatin III in callus extracts was confirmed by TLC, HPLC using a photodiode array detector and mass spectrometry (CI-MS). The highest equivalent content of the taxoid derivatives (7.83 mg/100 g dry wt.) was detected in an extract from leaf-derived callus.

Polyclonal antibodies raised against 2'-succinyltaxol-bovine serum albumin (BSA) conjugate were used for the immunodetection of bioactive taxoids in chromatographic fractions of the stem bark extract of Taxus baccata. In addition to taxol, cephalomannine, and baccatin III, two taxoids were isolated and their structures were elucidated as 4 alpha,7 beta-diacetoxy-2 alpha,9 alpha-dibenzoxy-5 beta,20-epoxy-10 beta, 13 alpha, 15-trihydroxy-11(15-->1)-abeo-tax-11-ene[5] and taxol C [6] using spectroscopic methods.

The amino acid sequence of the cysteine proteinase CC-III from the latex of the subtropical species Carica candamarcensis Hook has been determined with the exception of seven residues (pos. 180-186). It was deduced from the sequence analysis of the whole chain and peptides obtained by tryptic, chymotryptic, peptic and thermolysinolytic hydrolysis. CC-III consists of 214 amino acid residues. Out of a total of eight cysteine residues, six are located at positions involved in the formation of the three disulfide bridges stabilizing the structure of papain related enzymes. CC-III from Carica candamarcensis is a glycoprotein with the carbohydrate moiety bound to asparagine at position 44. Out of 210 residues compared with the sequences of the four cysteine proteinases of Carica papaya L., CC-III shares 125 identical ones (59.5%) with papain, 142 (67.6%) with papaya proteinase IV, 146 (69.5%) with papaya proteinase III and 156 (74.3%) with chymopapain. All amino acid residues constituting the active site and subsite S2 in chymopapain are conserved in CC-III with the exception of the substitution Leu157--> Val in the latter. This fact as well as the highest degree of identity between CC-III and chymopapain point to a similar specificity of both enzymes and thus CC-III might be a suitable substitute for chymopapain as a chemonucleolytic agent.

A high-sensitive ELISA method was developed for the detection and semi-quantitative determination of 10-deacetylbaccatin III and its structurally related compounds in crude extract of Taxus sp. plants and tissue cultures. The antibodies were raised in rabbits using 7- or 10-succinyl-10-deacetylbaccatin III-BSA conjugate as immunogen. The working range of the assay was from 0.003 to 1.000 ng (0.09 to 31.33 nM) of 10-deacetylbaccatin III per assay. The cross-reacting material in crude plant extract was examined by chromatographic (silica gel CC, HPLC) and immunoassay methods. Study on the evaluation of cross-reacting material in crude Taxus plant extracts showed that at least 80% of the immunosignal correspond to 10-deacetylbaccatin III in the extract. The ELISA method was applied to investigate the 10-deacetylbaccatin III equivalent content in crude extracts of 19 plants species including Taxaceae, Taxodiaceae and Pinaceae species. The 10-deacetylbaccatin III-like structure was only detected in Taxus and Torreya sp. The results indicate that this immunoassay is a useful tool for the rapid screening of species, varieties or individual plants out of a wide population. The distribution of 10-deacetylbaccatin III equivalent content in 9-month old Taxus plantlets cultivated in vitro as well as in callus culture was investigated.

Hairy root cultures of Hyoscyamus muticus were established using Agrobacterium rhizogenes ATCC 15834. In one out of 8 clones established, an unusual root tip formation was observed after transfer of cultures from half-strength Murashige and Skoog (1962) to White's medium (1939). This phenomenon was associated with the production of a fine brownish cell suspension culture. Hairy root development resumed after transfer of the root tips from White to half-strength Murashige and Skoog medium. After plating the isolated brownish cells on hormone-free half-strength Murashige and Skoog or White solid medium, callus proliferation was observed, and then redifferentiation of hairy roots occurred. The polymerase chain reaction analysis of the H. muticus hairy root (clone Z2) revealed that only the tl region of the T-DNA was integrated. The growth and the production of five tropane alkaloids by this clone were examined.

The cysteine-proteinase chymopapain from Carica papaya L. is used for chemonucleolysis of damaged human intervertebral spinal discs. The purification of this enzyme is difficult. To overcome these problems, we were looking for a substitute among the cysteine-proteinases of Carica candamarcensis Hook. The latex from unripe fruits was collected in an aqueous solution of methylethanethiolsulfonate to prevent proteolytic activities. The soluble fraction of the lypophilized product provided four enzymatically active peaks (CC-I-CC-IV) during chromatography on CM-Sephadex C-50 in sodium acetate buffer, pH5.0. They could be further purified by rechromatography under similar conditions. The isolated enzymes have been characterized by PAGE, analysis of the Fourier transform infrared spectra, preliminary studies of their specificities as well as a comparison of the N-terminal amino-acid sequences up to position 43. CC-III proved to be glycosylated. CC-I and CC-III from Carica candamarcensis Hook are suggested to correspond to papain and chymopapain from Carica papaya L., respectively.

Eighty-three patients with rapidly progressing breast cancer (RPBC) were entered into a study of primary chemotherapy (cyclophosphamide, methotrexate, and 5-fluorouracil) and subsequent randomization to surgery or radiotherapy for control of local/regional disease. Eighty-three of these patients with redness, warmth, and edema compatible with clinical "inflammatory breast cancer" served as the focus for our analysis of factors associated with improved survival. The stage-specific disease-free intervals (DFI) of 36 and 21 months were substantially longer than in the earlier series (26 and 16 months) from the same institution. The evaluation of individual prognostic indicators revealed that the initial tumor size and the initial response to chemotherapy were the two independent factors most important in predicting the DFI. The continuing unmaintained 1-year remission in at least 12 patients supports the rationale for aggressive therapy in RPBC or "inflammatory breast cancer."

Two immunostimulating peptides were isolated from human milk proteins by enzymatic digestion, the tripeptide GLF and the hexapeptide VEPIPY. These peptides increased the phagocytosis of human and murine macrophages and protected mice against Klebsiella pneumoniae infection. The present study showed that this activity may be correlated to the presence of specific binding sites on human blood phagocytic cells. The receptor molecules implicated were different for the two peptides. [3H]GLF specifically bound to PMNL and monocytes, whereas [3H]VEPIPY only bound to monocytes. The leukemic promyelocytic cell line HL-60 differentiated into granulocytes or into macrophages (depending on inducer used) coroborated these results. Specific binding of [3H]GLF on plasma membrane preparations of human PMNL (20 degrees C) was saturable and Scatchard analysis indicated two classes of binding sites: high-affinity sites of Kd 2.3 +/- 1.0 nM and Bm 60 +/- 9 fmol/mg protein and low-affinity sites of Kd 26.0 +/- 3.5 nM and Bm 208 +/- 45 fmol/mg protein. [3H]GLF binding was inhibited in a concentration-dependent manner by various analogous peptides, such as LLF, GLY, LLY and RGDGLF, but not by RGD, RGDS, VEPIPY and the chemotactic peptide f-Met-Leu-Phe (f-MLF). Only at high concentrations the direct analog MLF competed with labeled GLF. An important inhibitory effect was also observed with C1q component of the complement whereas C3 and BSA were uneffective. Specific binding of [3H]VEPIPY on monocyte membranes (20 degrees C) was saturable and Scatchard analysis was consistent with one class of binding sites of Kd 3.7 +/- 0.3 nM and Bm 150 +/- 6 fmol/mg protein.

An ELISA-assay for the detection and the semi-quantitative determination of taxane diterpenoids structurally related to taxol found in Taxus sp. has been developed. The antiserum was raised in rabbits using a 2'-succinyltaxol-bovine serum albumin conjugate as immunogen. The working range of the assay was from 1 to 100 ng of taxol. In order to improve the production of taxol, preliminary experiments have been performed on crude extracts of several Taxus sp.; the results indicate that the present immunoassay is an useful tool for the rapid screening of species, varieties or individual plants out of a large population as well as for tissue cultures analysis.

Clinical and radiographic examination of 581 patients with histologically verified breast cancer has permitted us to define a subgroup having a significantly poorer prognosis than other patients. Their condition, called "poussée évolutive" (rapidly progressing), is characterized by rapid tumor growth and/or inflammation adjacent to the tumor. Statistical analysis of the survival of M0 patients (412 of the 581) shows that the diagnosis of "poussée évolutive" provides prognostic information beyond that given by T and N classifications and after delay between initial symptoms and diagnosis have been considered. Six years of clinical experience with this condition are discussed.

Conflicting opinions exist concerning clinical and pathological presentation, as well as evolution and prognosis, of breast cancer in young women. The roles of associated pregnancy and lactation on these parameters is also unclear. These two conditions are studied in the present work through the comparison of two breast cancer patient age groups: patients under the age of 30 (Group A) and premenopausal patients aged 45-49 (Group B). Rapidly growing and/or inflammatory breast cancer (rapidly progressing breast cancer: RPBC)--a special form of Breast Cancer with a poor prognosis very frequent in the Tunisian breast cancer population--was more often present among Group A patients. This difference is a consequence of the more frequent association of this breast cancer group with pregnancy or lactation; nearly all the cases of breast cancer associated with pregnancy or lactation are RPBC. For breast cancer without the pregnancy/lactation association, the younger group generally shows poorer histological grading and more severe evolution. The number of patients in our study is not really sufficient to allow statistically significant conclusions, but it does seem clear that young age and associated pregnancy/lactation are aggravating factors in Tunisian breast cancer patients.