Biology subjects

Cruz, A.

Publications and source records attributed to Cruz, A..

3 recordsLinked to original sources

bioRxiv2019

Cross-Infectivity of Vorticella across Genera of Mosquitoes for Development of Biological Mosquito Control Strategies

Protozoans in general comprise about one-third of the parasitic species infecting arthropod vectors, the role of free-living ciliates on mosquitoes have been insufficiently studied either due to their low pathogenicity or being facultative parasites. Studies have shown that exposure of Paramecium ciliate protists, like Vorticella species, to first instar Cx. nigripalpus larvae delayed larval development and reduced biomass of emerged adults due to competition for food sources like bacteria and other microbes essential to mosquito growth and survival. Thus, we report on the capacity of a Vorticella protozoans ability to cross-infect host species and parasitize multiple mosquito larvae. The unique adapted behavior with the ability to remain on the exuviae in tree hole habitats provides a novel delivery system to develop products for target species-specific mosquitocides, larvicides, or viricides to be applied and sustained in aquatic systems.

ecology↗

bioRxiv2019

Freezing displayed by others is a learned cue of danger resulting from co-experiencing own-freezing and shock

Social cues of threat are widely reported [1-3], whether actively produced to trigger responses in others, such as the emission of alarm calls, or by-products of an encounter with a predator, like the defensive behaviors themselves, such as an escape flight [4-14]. Although the recognition of social alarm cues is often innate [15-17], in some instances it requires experience to trigger defensive responses [4,7]. One mechanism proposed for how learning from self-experience contributes to social behavior is that of auto-conditioning, whereby subjects learn to associate their own behaviors with the relevant trigger events. Through this process the same behaviors, now displayed by others, gain meaning. [18,19 but see: 20]. Although it has been shown that only animals with prior experience with shock display observational freezing [21-25] suggesting that auto-conditioning could mediate this process, evidence for this hypothesis was lacking. Previously we found that when a rat freezes, the silence that results from immobility triggers observational freezing in its cage-mate, provided the cage-mate had experienced shocks before [24]. Hence, in our study auto-conditioning would correspond to rats learning to associate shock with their own response to it - freezing. Using a combination of behavioral and optogenetic manipulations, here we show that freezing becomes an alarm cue by a direct association with shock. Our work shows that auto-conditioning can indeed modulate social interactions, expanding the repertoire of cues that mediate social information exchange, providing a framework to study how the neural circuits involved in the self-experience of defensive behaviors overlap with the ones involved in socially triggered defensive behaviors.

animal behavior and cognition↗

bioRxiv2019

Non-genetic intra-tumor heterogeneity is a major predictor of phenotypic heterogeneity and ongoing evolutionary dynamics in lung tumors

Impacts of genetic and non-genetic intra-tumor heterogeneity (ITH) on tumor phenotypes and evolvability remain debated. We analyzed ITH in lung squamous cell carcinoma (LUSC) at the levels of genome, transcriptome, tumor-immune interactions, and histopathological characteristics by multi-region profiling and using single-cell sequencing data. Overall, in LUSC genomic heterogeneity alone was a weak indicator of intra-tumor non-genetic heterogeneity at immune and transcriptomic levels that impacted multiple cancer-related pathways including those related to proliferation and inflammation, which in turn contributed to intra-tumor regional differences in histopathology and subtype classification. Genome, transcriptome, and immune-level heterogeneity influenced different aspects of tumor evolution. Tumor subclones had substantial differences in proliferation score, suggestive of non-neutral clonal dynamics. Scores for proliferation and other cancer-related pathways also showed intra-tumor regional differences, sometimes even within the same subclones. Neo-epitope burden negatively correlated with immune infiltration, indicating potential immune-mediated purifying selection on acquired mutations in these tumors. Taken together, our observations suggest that non-genetic heterogeneity is a major determinant of heterogeneity in histopathological characteristics and impacts evolutionary dynamics in lung cancer.

cancer biology↗