[
Phytomedicine,
2017]
BACKGROUND: Biofilms contribute to the pathogenesis of many chronic and difficult-to eradicate infections whose treatment is complicated due to the intrinsic resistance to conventional antibiotics. As a consequence, there is an urgent need for strategies that can be used for the prevention and treatment of biofilm-associated infections. The combination therapy comprising an antimicrobial drug with a low molecular weight (MW) natural product and an antimicrobial drug (antifungal or antibacterial) appeared as a good alternative to eradicate biofilms. PURPOSE: The aims of this review were to perform a literature search on the different natural products that have showed the ability of potentiating the antibiofilm capacity of antimicrobial drugs, to analyze which are the antimicrobial drugs most used in combination, and to have a look on the microbial species most used to prepare biofilms. RESULTS: Seventeen papers, nine on combinations against antifungal biofilms and eight against antibacterial biofilms were collected. Within the text, the following topics have been developed: breaf history of the discovery of biofilms; stages in the development of a biofilm; the most used methodologies to assess antibiofilm-activity; the natural products with capacity of eradicating biofilms when acting alone; the combinations of low MW natural products with antibiotics or antifungal drugs as a strategy for eradicating microbial biofilms and a list of the low MW natural products that potentiate the inhibition capacity of antifungal and antibacterial drugs against biofilms. CONCLUSIONS AND PERSPECTIVES: Regarding combinations against antifungal biofilms, eight over the nine collected works were carried out with in vitro studies while only one was performed with in vivo assays by using Caenorhabditis elegans nematode. All studies use biofilms of the Candida genus. A 67% of the potentiators were monoterpenes and sesquiterpenes and six over the nine works used FCZ as the antifungal drug. The activity of AmpB and Caspo was enhanced in one and two works respectively. Regarding combinations against bacterial biofilms, in vitro studies were performed in all works by using several different methods of higher variety than the used against fungal biofilms. Biofilms of both the gram (+) and gram (-) bacteria were prepared, although biofilm of Staphylococcus spp. were the most used in the collected works. Among the discovered potentiators of antibacterial drugs, 75% were terpenes, including mono, di- and triterpenes, and, among the atibacterial drugs, several structurally diverse types were used in the combinations: aminoglycosides, -lactams, glucopeptides and fluoroquinolones. The potentiating capacity of natural products, mainly terpenes, on the antibiofilm effect of antimicrobial drugs opens a wide range of possibilities for the combination antimicrobial therapy. More in vivo studies on combinations of natural products with antimicrobial drugs acting against biofilms are highly required to cope the difficult to treat biofilm-associated infections.
[
J Exp Zool,
1999]
A memorable workshop, focused on causal mechanisms in metazoan evolution and sponsored by NASA, was held in early June 1998, at MBL. The workshop was organized by Mike Levine and Eric H. Davidson, and it included the PI and associates from 12 different laboratories, a total of about 30 people. Each laboratory had about two and one half hours in which to represent its recent research and cast up its current ideas for an often intense discussion. In the following we have tried to enunciate some of the major themes that emerged, and to reflect on their implications. The opinions voiced are our own. We would like to tender apologies over those contributions we have not been able to include, but this is not, strictly speaking, a meeting review. Rather we have focused on those topics that bear more directly on evolutionary mechanisms, and have therefore slighted some presentations (including some of our own), that were oriented mainly toward developmental processes. J. Exp. Zool. (Mol. Dev. Evol. ) 285:104-115, 1999.
[
International Review of Cytology,
1986]
The problem of cell-specific gene expression has long been a major concern to developmental biologists. Why and how specific genes are expressed only in certain differentiated cells and not in others are of vital importance. Many well-documented examples of differentiated cell types expressing quantitative and/or qualitative changes in gene expression now exist. For example, Galau et al. (1976) demonstrated that different sets of genes are expressed during development and in different adult tissues of the sea urchin. More recently, Angerer and Davidson (1984) have used in situ hybridization of specific DNA probes to demonstrate the expression of lineage-specific genes long before morphological differentiation. Other examples include the ovalbumin gene, known to be expressed only in hormone-stimulated oviducts, and the globin genes expressed at various developmental stages in differentiating erythrocytes. Many other examples of cell-specific gene expression are known, including the silk moth chorion proteins, the glue proteins in Drosophila, and a-amylase in mammals. Detailed molecular analysis of genes has provided important information on the mechanisms of gene expression. For example, numerous studies have examined the role of chromatin structure as well as the significance of specific sequences in the transcription and translation of eukaryotic genes. Furthermore, studies of the globin, actin, immunoglobulin, histone, and silk moth chorion genes have demonstrated the existence of gene families with suggested importance for the evolution of new functions for old genes. In addition, the detailed study of multigene families has provided vital information on the mechanisms of cell-specific gene expression as seen, for example, in the temporal and spatial regulation of different members of the actin gene family....