Identification of a Huperzine A-producing endophytic fungus from Phlegmariurus taxifolius

Molecular Biology Reports - Highly prized huperzine A (Hup A), a natural alkaloid formerly isolated from the Chinese medicinal plant Huperzia serrata, has been widely used for the treatment of...     

Pancreatic ductal adenocarcinomas from Mexican patients present a distinct genomic mutational pattern

Molecular Biology Reports - Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers in humans, with less than 5% 5-year survival rate. PDAC is characterized by a small number of...     

When an advantageous reproductive trait turns bad: Eggs of the threatened fish Genidens barbus as a natural bait in recreational fisheries

This study describes a recreational fishing method focused on marine catfish, Genidens barbus (Endangered-EN), through the adoption of its eggs as a natural bait during its reproductive period in southern Brazilian ecosystems. Male G. barbus perform parental care, collecting eggs released by females after the fertilization process. Owing to this male behavioural pattern during the reproductive period, these individuals are easily caught in recreational fisheries that use eggs of the same species as a natural bait. The current adoption of G. barbus eggs as bait may intensify the fishing pressure on its populations.     

The effects of pesticides on bacterial nitrogen fixers in peanut-growing area

In the peanut production, the applications of herbicides and fungicides are a common practice. In this work, studies done under field conditions demonstrated that pesticides affected negatively the number and nitrogenase activity of diazotrophic populations of soil. Agrochemical effects were not transient, since these parameters were not recovered to pre-treatment levels even 1 year after pesticides application. Results obtained from greenhouse experiments revealed that the addition of herbicide or fungicides diminished the free-living diazotrophs number reaching levels found in soil amended with the pesticides and that the number of symbiotic diazotrophs was not affected by the insecticide assayed. The soil nitrogenase activity was not affected by fungicides and glyphosate. The effect of pesticides on the nitrogen-fixing bacteria diversity was evaluated both in field and greenhouse experiments. Analysis of clone libraries generated from the amplification of soil nifH gene showed a diminution in the genetic diversity of this bacterial community.     

Liposomal temocene (m-THPPo) photodynamic treatment induces cell death by mitochondria-independent apoptosis

Background

The cell death pathway activated after photodynamic therapy (PDT) is controlled by a variety of parameters including the chemical structure of the photosensitizer, its subcellular localization, and the photodynamic damage induced. The present study aims to characterize a suitable m-THPPo liposomal formulation, to determine its subcellular localization in HeLa cells and to establish the cell death mechanisms that are activated after photodynamic treatments.

Methods

Liposomes containing m-THPPo were prepared from a mixture of DPPC and DMPG at a 9:1 molar ratio. In order to procure the best encapsulation efficiency, the m-THPPo/lipid molar ratio was considered. HeLa cells were incubated with liposomal m-THPPo and the subcellular localization of m-THPPo was studied. Several assays such as TUNEL, annexin V/propidium iodide and Hoechst-33258 staining were performed after photodynamic treatments. The apoptotic initiation was assessed by cytochrome c and caspase-2 immunofluorescence.

Results

m-THPPo encapsulated in liposomes showed a decrease of the fluorescence and singlet oxygen quantum yields, compared to those of m-THPPo dissolved in tetrahydrofuran. Liposomal m-THPPo showed colocalization with LysoTracker® and it induced photoinactivation of HeLa cells by an apoptotic mechanism. In apoptotic cells no relocalization of cytochrome c could be detected, but caspase-2 was positive immediately after photosensitizing treatments.

Conclusions

Photodynamic treatment with liposomal m-THPPo leads to a significant percentage of apoptotic morphology of HeLa cells. The activation of caspase-2, without the relocalization of cytochrome c, indicates a mitochondrial-independent apoptotic mechanism.

General significance

These results provide a better understanding of the cell death mechanism induced after liposomal m-THPPo photodynamic treatment.     

New trends in peptide-based anti-biofilm strategies: a review of recent achievements and bioinformatic approaches

Antimicrobial peptides (AMPs) have a broad spectrum of activity and unspecific mechanisms of action. Therefore, they are seen as valid alternatives to overcome clinically relevant biofilms and reduce the chance of acquired resistance. This paper reviews AMPs and anti-biofilm AMP-based strategies and discusses ongoing and future work. Recent studies report successful AMP-based prophylactic and therapeutic strategies, several databases catalogue AMP information and analysis tools, and novel bioinformatics tools are supporting AMP discovery and design. However, most AMP studies are performed with planktonic cultures, and most studies on sessile cells test AMPs on growing rather than mature biofilms. Promising preliminary synergistic studies have to be consubstantiated and the study of functionalized coatings with AMPs must be further explored. Standardized operating protocols, to enforce the repeatability and reproducibility of AMP anti-biofilm tests, and automated means of screening and processing the ever-expanding literature are still missing.