Biology subjects

Vaca, M.

Publications and source records attributed to Vaca, M..

3 recordsLinked to original sources

bioRxiv2025

Permeabilization with fenchone enhances cryopreservation of Drosophila embryos

The difficulty of cryopreservation has long been a limitation of Drosophila melanogaster as a genetic model organism. Here we report a statistically significant improvement in the efficiency of Drosophila cryopreservation by substituting limonene with the monoterpenoid fenchone in the embryo permeabilization step of a previously published method. We found that fenchone-permeabilized embryos exhibit greater uptake of cryoprotectant compared with those permeabilized by limonene, and a ~6-fold increase in the rate of egg-to-adult survival for wild-type flies. Using this improved protocol, we successfully cryopreserved and revived precious strains after 12 months of storage in liquid nitrogen. These results suggest that fenchone is a superior permeabilizing agent for fly embryo cryopreservation, expanding possibilities for the long-term maintenance of Drosophila and other insect species. Further refinement of this approach may enable cryopreservation to replace continuous culture as the method of choice for routine maintenance of fly stocks.

physiology↗

bioRxiv2024

Genome-wide screen overexpressing mycobacteriophage Amelie genes identifies multiple inhibitors of mycobacterial growth

The genome sequences of thousands of bacteriophages have been determined and functions for many of the encoded genes have been assigned based on homology to characterized sequences. However, functions have not been assigned to more than two-thirds of the identified phage genes as they have no recognizable sequence features. Recent genome-wide overexpression screens have begun to identify bacteriophage genes that encode proteins that reduce or inhibit bacterial growth. This study describes the construction of a plasmid-based overexpression library of 76 genes encoded by Cluster K1 mycobacteriophage Amelie, which is genetically similar to Cluster K phages Waterfoul and Hammy recently described in similar screens and closely related to phages that infect clinically important mycobacteria. 26 out of the 76 genes evaluated in our screen, encompassing 34% of the genome, reduced growth of the host bacterium Mycobacterium smegmatis to various degrees. More than one-third of these 26 toxic genes have no known function, and 10 of the 26 genes almost completely abolished host growth upon overexpression. Notably, while several of the toxic genes identified in Amelie shared homologs with other Cluster K phages recently screened, this study uncovered eight previously unknown gene families that exhibit cytotoxic properties, thereby broadening the repertoire of known phage-encoded growth inhibitors. This work, carried out under the HHMI-supported SEA-GENES project (Science Education Alliance Gene-function Exploration by a Network of Emerging Scientists), underscores the importance of comprehensive overexpression screens in elucidating genome-wide patterns of phage gene function and novel interactions between phages and their hosts.

microbiology↗

bioRxiv2019

Hydrogen peroxide as regeneration-initiation signal that activates pERK to trigger planarian regeneration

Despite the extensive research on molecular pathways controlling the process of regeneration in planarians and other regeneration models, little is known about the actual initiation signals necessary to induce regeneration. Previously the involvement of ROS, EGFR and MAPK/ERK has been demonstrated during planarian regeneration, however the exact interplay has not been yet described. By selectively interfering with major mediators in all three key parts (ROS, EGFR & MAPK/ERK), we were able to identify amputation/wound-induced ROS, and H2O2 specifically, as upstream cue in activating regeneration-initiation. In addition, our results demonstrate new relationships between regeneration related ROS production and MAPK/ERK activation at early regeneration stages, as well as the involvement of the EGFR-signaling pathway. In summary, our results suggest a new and more extensive signaling model with ROS, and H2O2, highlighted as upstream initiation-factor and its important functions in the downstream EGFR-MAPK/ERK pathway during planarian regeneration.

developmental biology↗