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Biomedical subjects

F Fons

Publications and source records attributed to F Fons.

4 recordsLinked to original sources
PubMed2006

Biodegradation of phenanthrene, spatial distribution of bacterial populations and dioxygenase expression in the mycorrhizosphere of Lolium perenne inoculated with Glomus mosseae.

Interactions between the plant and its microbial communities in the rhizosphere control microbial polycyclic aromatic hydrocarbons (PAH) biodegradation processes. Arbuscular mycorrhizal (AM) fungi can influence plant survival and PAH degradation in polluted soil. This work was aimed at studying the contribution of the mycorrhizosphere to PAH biodegradation in the presence of ryegrass (Lolium perenne L., cv. Barclay) inoculated with Glomus mosseae (BEG 69) by taking into account the structure and activity of bacterial communities, PAH degrading culturable bacteria as a function of the distance from roots. Ryegrass was grown in compartmentalized systems designed to harvest successive sections of rhizosphere in lateral compartments polluted or not with phenanthrene (PHE). Colonization of roots by G. mosseae (BEG 69) modified the structure and density of bacterial populations in the mycorrhizosphere, compared to the rhizosphere of non-mycorrhizal plants. G. mosseae increased the density of culturable heterotrophic and PAH degrading bacteria beyond the immediate rhizosphere in the presence of PHE, and increased the density of PAH degraders in the absence of the pollutant. Biodegradation was not significantly increased in the mycorrhizosphere, compared to control non-mycorrhizal plants, where PHE biodegradation already reached 92% after 6 weeks. However, dioxygenase transcriptional activity was found to be higher in the immediate mycorrhizosphere in the presence of G. mosseae (BEG 69).

Bacteria↗
PubMed2003

Effects of Gypsophila saponins on bacterial growth kinetics and on selection of subterranean clover rhizosphere bacteria.

Plant secondary metabolites, such as saponins, have a considerable impact in agriculture because of their allelopathic effects. They also affect the growth of soil microorganisms, especially fungi. We investigated the influence of saponins on rhizosphere bacteria in vitro and in soil conditions. The effects of gypsophila saponins on the growth kinetics of rhizosphere bacteria were studied by monitoring the absorbance of the cultures in microtiter plates. Gypsophila saponins (1%) increased the lag phase of bacterial growth. The impact of gypsophila saponins on subterranean clover rhizosphere was also investigated in a pot experiment. The addition of gypsophila saponins did not modify clover biomass but significantly increased (twofold with 1% saponins) the weight of adhering soil. The number of culturable heterotrophic bacteria of the clover rhizosphere was not affected by the addition of gypsophila saponins. Nevertheless, the phenotypical characterization of the dominant Gram-negative strains of the clover rhizosphere, using the Biolog system, showed qualitative and quantitative differences induced by 1% saponins. With the addition of saponins, the populations of Chryseomonas spp. and Acinetobacter spp., the two dominant culturable genera of control clover, were no longer detectable or were significantly decreased, while that of Aquaspirillum dispar increased and Aquaspirillum spp. became the major genus. Aquaspirillum dispar and Aquaspirillum spp. were also the dominant rhizosphere bacteria of Gypsophila paniculata, which greatly accumulates these saponins in its roots. These results suggest that saponins may control rhizosphere bacteria in soil through rhizodeposition mechanisms.

Acinetobacter↗
PubMedDate not supplied

The effects on offspring of premature parturition.

The time of parturition defines the length of the intrauterine period of fetal life, a requisite to achieve adequate adaptation to the external environment. Immaturity, a condition whose severity is inversely related to the length of pregnancy, is the main determinant of the increased morbidity and mortality associated with preterm birth. Despite great advances in medical technology and expertise, mainly after the introduction of the neonatal intensive care units, only one- to two-thirds of infants from the subsets with lower birthweight/gestational age reach survival at discharge. Distinct major neurological and sensorial sequelae, including cerebral palsy, retinopathy of prematurity, and hearing loss, as well as reduced neuropsychological abilities, leading to deficient academic achievement and deterioration of several aspects of health status, are still highly prevalent among the most immature children. Interestingly, decreasing mortality rates, which are not followed by detectable increases of disability, are being observed in recent years. Future advances may be expected from clinical and basic research on uterine contractility and cervical softening. Also, changes in reproductive technology procedures, a main factor in the incidence of multiple pregnancies, and a more refined approach to obstetric care, compose some of the clinical interventions which may reduce the problem.

Developed Countries↗