Biology subjects

Rodriguez Lopez, C.

Publications and source records attributed to Rodriguez Lopez, C..

4 recordsLinked to original sources

bioRxiv2026

Diet quality shapes development and feeding circuits in poison frog tadpoles

From birth, offspring must balance internal energy state with the costs of signaling need to caregivers to secure nutrition for growth and healthy development. How diet during this period shapes the developing brain and behavior is a central question in biology, with growing relevance for understanding the developmental origins of metabolic disorders such as obesity. Yet the effects of early nutrition on growth, neural development, and behavior are rarely examined together within a single system. Here, we use poison frog tadpoles as a vertebrate model in which offspring develop outside a womb, can be reared independently under precisely controlled dietary conditions, and display diverse behaviors at a young age. By independently manipulating dietary quantity and quality, we link early nutrition to growth, brain development, and social behavior during ontogeny. Diet quantity increased body size, whereas diet quality accelerated development. Diet quality, but not quantity, shaped behavior: tadpoles fed a natural diet showed increased affiliation during food solicitation and reduced feeding, while aggression and risk avoidance remained unchanged. Diet also affected body and brain development differently, with artificial diets producing larger tadpoles but reduced volume in some brain regions, including areas associated with begging behavior. Anorexigenic urocortin-1 neurons were active during begging behavior and, together with another anorexigenic midbrain population, decreased in abundance under an artificial diet. Functionally, urocortin-1 reduced feeding without directly increasing begging, suggesting it gates socio-positive behavior by suppressing a competing drive rather than initiating it. Together, this work shows that dietary quantity and quality act on distinct developmental processes, with diet quality programming the brain circuits that permit begging behavior while growth is determined by food quantity.

neuroscience↗

bioRxiv2026

A Versatile AAV-TH-SNCA Model to Study Early α-Synuclein Pathology and Intervention

Adeno-associated viral (AAV)-mediated overexpression of human wildtype -synuclein (-syn) in the substantia nigra (SN) is a widely used approach to model Parkinsons disease (PD) in rodents. However, variability in the ability of AAV-based systems to induce nigrostriatal pathology and motor deficits has limited reproducibility across studies, especially in mice. Here, we systematically optimized key vector features - AAV serotype, promoter, viral titer - to establish a highly efficient and reliable mouse model of PD. We compared the tropism and expression efficiency of mixed AAV2/1 and AAV2/rh10 serotypes combined with three promoters - CMV enhancer/chicken {beta}-actin (CBA), human Synapsin (hSYN), and rat Tyrosine Hydroxylase (TH) - to drive human -syn gene (SNCA) expression in nigral dopaminergic neurons. The AAV.TH.SNCA vector, delivered at an optimized titer, achieved selective and sustained -syn overexpression in nigral neurons, resulting in nigro-striatal neurochemical changes and progressive motor deficits preceding overt neuronal loss. Fine tuning -syn expression proved critical for detecting early disease processes: lower AAV.TH.SNCA titer induced early pathological signatures, including -syn hyperphosphorylation and neuroinflammation, whereas higher titers produced robust nigrostriatal degeneration not achieved with other promoter constructs. Notably, we demonstrate that motor and neurochemical impairments can occur prior to dopaminergic cell death, implicating microglial activation and -syn pathology as primary drivers of dysfunction. This observation is consistent with human genetic evidence showing that triplication of the wild-type SNCA gene alone can cause Parkinsonian pathology, highlighting that our model enables the use of a single experimental reagent to investigate the molecular, cellular, and behavioral consequences of controlled increases in -syn expression. This novel AAV.TH.SNCA model provides a powerful and versatile platform for investigating mechanisms of a -syn-mediated neurotoxicity and for evaluating disease modifying interventions targeting early, pre-degenerative stages of PD. HighlightsO_LITitrated -syn expression uncouples early dysfunction from dopaminergic neuron loss C_LIO_LIAAV2/rh10-TH-SNCA model captures prodromal and degenerative PD stages C_LIO_LIMotor deficits arise from -syn pathology and nigral molecular changes before neurodegeneration C_LI

neuroscience↗

bioRxiv2020

Microbial function is related to behavior of an invasive anuran

Gut bacterial communities influence, and are influenced by, the behaviour and ecology of their hosts. Those interactions have been studied primarily in humans and model organisms, but we need field research to understand the relationship between an organisms gut bacteria and its ecological challenges, such as those imposed by rapid range expansion (as in invasive species) and the presence of host-manipulating parasites. Cane toads (Rhinella marina) provide an excellent model system in this respect, because the species ongoing colonization of Australia has enforced major changes in phenotypic traits (including behaviour), and lungworm parasites (Rhabdias pseudosphaerocephala) modify host gut function in ways that enhance the viability of lungworm larvae. We collected female toads from across the species invasive range and studied their morphology, behaviour, parasite infection status and gut bacterial community. Range-core versus range-edge toads differed in morphology, behaviour, gut bacterial composition and predicted gut bacterial function but did not differ in the occurrence of parasite infection nor in the intensity of infection. Toads infected with lungworms differed from uninfected conspecifics in gut bacterial composition and diversity. Our study demonstrates strong associations between gut bacterial community and host ecology and behaviour.

microbiology↗

bioRxiv2020

Dicistronic tRNA-mRNA transcripts in grapevine (Vitis vinifera) display distinct, regional expression patterns that correlate with tRNA expression

Transfer RNAs (tRNA) are crucial adaptor molecules between messenger RNA (mRNA) and amino acids. Recent evidence in plants suggests that dicistronic tRNA-like structures also act as mobile signals for mRNA transcripts to move between distant tissues. Co-transcription is not a common feature in the plant nuclear genome and, in the few cases where polycistronic transcripts have been found, they include non-coding RNA species such as small nucleolar RNAs and microRNAs. It is not known, however, the extent to which dicistronic transcripts of tRNA and mRNAs are expressed in field-grown plants, or the factors contributing to their expression. We analysed tRNA-mRNA dicistronic transcripts in the major horticultural crop grapevine (Vitis vinifera) using a novel pipeline developed to identify dicistronic transcripts from high-throughput RNA sequencing data. We identified dicistronic tRNA-mRNA in leaf and berry samples from 22 commercial vineyards. Of the 124 tRNA genes that were expressed in both tissues, 18 tRNA were expressed forming part of 19 dicistronic tRNA-mRNAs. The presence and abundance of dicistronic molecules was tissue and geographic sub-region specific. In leaves, the expression patterns of dicistronic tRNA-mRNAs significantly correlated with tRNA expression, suggesting that their transcriptional regulation might be linked. We also found evidence of syntenic genomic arrangements of tRNAs and protein coding genes between grapevine and Arabidopsis thaliana, and widespread prevalence of dicistronic tRNA-mRNA transcripts among vascular land plants but no evidence of these transcripts in nonvascular lineages. This suggests that the appearance of plant vasculature and tRNA-mRNA occurred concurrently during the evolution of land plants.

plant biology↗