La structure du capital des petites et moyennes entreprises industrielles tunisiennes

L’objectif de cet article est d’étudier la pertinence des différentes théories de financement dans l’explication du choix de la structure du capital au sein des petites et moyennes entreprises industrielles tunisiennes (PMI). Nous avons effectué une analyse empirique sur 300 PMI tunisiennes durant la période allant de 1997 à 2003. Nos résultats montrent que la décision de financement dans ces entreprises pourrait être expliquée par les principales théories de structure du capital (théorie fiscale, théorie de l’endettement optimal et théorie du financement hiérarchique). La théorie du financement hiérarchique semble le mieux convenir pour expliquer la politique de financement des PMI.The principal aim of this paper is to test the relevance of the different financing theories used to explain the capital structure of the Tunisian small and medium enterprises (SME). To establish the main determinants of their capital structure, our study is based on a sample of 300 SME, over a period from 1997 to 2003. Our results show that the financing decision in these companies could be explained by the main capital structure theories: fiscal theory, trade-off theory and pecking order theory. Among all these theories, the pecking order theory seems to fit in the explanation of SMEs debt policy.La puntería principal de este papel es probar la importancia de las diversas teorías del financiamiento usadas para explicar la estructura de capital de las empresas pequeñas y medias tunecinas (PyMEs). Para establecer los determinantes principales de su estructura de capital, nuestro estudio se basa en una muestra de 300 PyMEs, sobre un período 1997-2003. Nuestros resultados demuestran que la decisión del financiamiento en estas compañías se podría explicar por la teoría principal de la estructura de capital: teoría fiscal, teoría de la compensación y pico-tear teoría de la orden. Entre todas estas teorías, la teoría de la orden que picotea se parece caber en la explicación de la política de la deuda de PyMEs.Die Zielsetzung dieses Artikels besteht darin, die Aussagekraft verschiedener Finanzierungstheorien bei der Wahl der Struktur des Kapitals von kleinen und mittleren tunesischen Industrieunternehmen zu untersuchen. Wir haben eine empirische Untersuchung während 1997 bis 2003 bei 300 besagten tunesischen Unternehmen durchgeführt. Die erhaltenen Resultate zeigen auf, dass die Ent-scheidung über die Art der Finanzierung in diesen Unternehmen mit den gängig-sten Finanzierungstheorien (Steuer-Theorie, Theorie der optimalen Verschuldung und Theorie der hierarchischen Finanzierung) erklärt werden kann. Die Theorie der hierarchischen Finanzierung scheint sich am besten zur Erklärung der Finanzierungspolitik zu eignen.Unsere Ergebnisse zeigen, dass die Finanzierungsentscheidungen in die-sen Unternehmen durch die wesentlichen Theorien der Kapitalstruktur erklärt werden könnte (fiskalische Theorie, Theorie der optimalen Verschuldung und hier-archische Finanzierungstheorie). Die hierarchische Finanzierungstheorie ist am besten geeignet, um die Finanzierungspolitik der kleinen und mittleren Industri-eunternehmen zu erklären

Biopriming of Durum Wheat Seeds with Endophytic Diazotrophic Bacteria Enhances Tolerance to Fusarium Head Blight and Salinity

There is growing interest in the use of bio inoculants based on plant growth-promoting bacteria (PGPB) to promote plant growth under biotic and abiotic stresses. Here, we provided a detailed account of the effectiveness of a number of endophytic PGPB strains, isolated from the roots of the halophyte Salicornia brachiata in promoting durum wheat growth and enhancing its tolerance to salinity and fusarium head blight (FHB) disease. Bacillus spp. strains MA9, MA14, MA17, and MA19 were found to have PGPB characteristics as they produced indole-3-acetic acid, siderophores, and lytic enzymes, fixed free atmospheric nitrogen, and solubilized inorganic phosphate in vitro. Additionally, the in vivo study that involved in planta inoculation assays under control and stress conditions indicated that all PGPB strains significantly (p < 0.05) increased the total plant length, dry weight, root area, seed weight, and nitrogen, protein, and mineral contents. Particularly, the MA17 strain showed a superior performance since it was the most efficient in reducing disease incidence in wheat explants by 64.5%, in addition to having the strongest plant growth promotion activity under salt stress. Both in vitro and in vivo assays showed that MA9, MA14, MA17, and MA19 strains were able to play significant PGPB roles. However, biopriming with Bacillus subtilis MA17 offered the highest plant growth promotion and salinity tolerance, and bioprotection against FHB. Hence, it would be worth testing the MA17 strain under field conditions as a step towards its commercial production. Moreover, the strain could be further assessed for its plausible role in bioprotection and growth promotion in other crop plants. Thus, it was believed that the strain has the potential to significantly contribute to wheat production in arid and semi-arid regions, especially the salt-affected Middle Eastern Region, in addition to its potential role in improving wheat production under biotic and abiotic stresses in other parts of the world

Isolation and Characterization of Lytic Pseudomonas aeruginosa Bacteriophages Isolated from Sewage Samples from Tunisia

Bacteriophages could be a useful adjunct to antibiotics for the treatment of multidrug-resistant Pseudomonas aeruginosa infections. In this study, lytic P. aeruginosa myoviruses PsCh, PsIn, Ps25, and Ps12on-D were isolated from Tunisian sewage samples. Phage Ps12on-D displayed an adsorption time of ~10 min, a short latency period (~10 min), and a large burst size (~115 PFU per infected cell) under standard growth conditions. All phages were active at broad temperature (4 °C to 50 °C) and pH (3.0 to 11.0) ranges and were able to lyse a wide variety of P. aeruginosa strains isolated from clinical and environmental samples worldwide. Illumina sequencing revealed double-stranded DNA genomes ranging from 87,887 and 92,710 bp with high sequence identity to Pseudomonas phage PAK_P1. All four phages based on sequence analysis were assigned to the Pakpunavirus genus. The presented characterization and preclinical assessment are part of an effort to establish phage therapy treatment as an alternative strategy for the management of multidrug-resistant P. aeruginosa infections in Tunisia

First Report of Filamentous Phages Isolated from Tunisian Orchards to Control Erwinia amylovora

Newly discovered Erwinia amylovora phages PEar1, PEar2, PEar4 and PEar6 were isolated from three different orchards in North Tunisia to study their potential as biocontrol agents. Illumina sequencing revealed that the PEar viruses carry a single-strand DNA genome between 6608 and 6801 nucleotides and belong to the Inoviridae, making them the first described filamentous phages of E. amylovora. Interestingly, phage-infected cells show a decreased swimming and swarming motility and a cocktail of the four phages can significantly reduce infection of E. amylovora in a pear bioassay, potentially making them suitable candidates for phage biocontrol.status: publishe