Neural basis of interactive behaviors in invertebrate animal model systems; impact of anthropogenic environmental changes on nervous system function of local river fauna
We are interested in understanding the neural basis of aggressive/submissive behavior and the establishment of dominance hierarchies, and the manner in which the underlying mechanisms may be modulated. We use as an experimental animal model freshwater prawns of the Macrobrachium genus (primarily rosenbergii and carcinus). Besides providing the well known benefits of other invertebrate model systems (e.g., simpler nervous systems, large identifiable neurons, stereotyped behaviors, etc.), the rosenbergii prawn has the added advantage of establishing dominance hierarchies on the basis of claw morphotype, a fixed characteristic, rather than only the basis of body size. Adult prawns progress through three claw morphotypes (small, yellow and blue) each corresponding to a higher level of dominance within a group.

Our research project integrates a variety of experimental approaches, including immunohistochemistry, confocal microscopy, in situ hybridization, western blot analysis, electrophysiology, and video recorded behavioral observation. We also collaborate with labs that work with proteomics and molecular biology (cloning, RT-PCR, expression). Rotating students can become involved in any of the ongoing projects and get exposed to any or all of these techniques.

We have characterized the location and distribution of various neurotransmitters/modulators (e.g., serotonin, octapamine, dopamine, GABA, glutamate, FMRF, proctolin, etc.) in the central nervous systems (CNS) of all three male and female morphotypes, as well as colocalizations and other forms of interactions among neurotransmitters systems, within each morphotype (e.g., dopamine and serotonin colocalization in single neurons, interactions between serotonin and dopamine neurons and octopamine and FMRF neurons, etc.).

We have used behavioral observation experiments to characterize interactive behaviors amongst morphotypes and have shown that the typical behavior of a morphotype can be manipulated to change into those of another morphotypes through systemic injections of neurotransmitters or agonists and antagonist of specific receptors.

Molecular biology techniques have been used to clone the fist crustacean aminergic receptors (two serotonergic and one octopaminergic). Antibodies and molecular probes have been raised against these cloned receptors and used to map their location and distribution in the prawn’s CNS, using immunohistochemistry, confocal microscopy and in situ hybridization techniques. Quantitative Western blot analysis, real-time RT-PCR, and proteomics techniques are being used to measure levels of expression of these receptors in different regions of the CNS of the three morphotypes of the prawn. [The latter two techniques, proteomics and molecular biology, are conducted in the labs of collaborators].

Other lines of experiments in progress include the expression and characterization of the cloned aminergic receptors, the cloning of other crustacean transmitter and neuropeptide receptors, the use of techniques of differential expression to isolate other target molecules that may be present in higher or lower amounts in each morphotype, and the isolation and identification of water-borne messenger molecules that communicate information on dominance status to animals with a group.

Another project is being developed to study the impact of anthropogenic changes in Puerto Rico urban rivers on behavior and underlying neural circuitry of crustacean species, soon to be expanded to also include other animals, such as insects, reptiles, and amphibians. This project compares the effects of urbanization on Puerto Rican rivers and its aquatic fauna. To do this, we first analyze three representative rivers in which we identify and quantify extraneous chemicals. The animal models, initially lab and local river prawns (rosenbergii and carcinus, respectively), are being exposed to pollutants found in the three rivers and are then being monitored to measure their locomotion and associated behaviors, along with assessment of the integrity of the underlying neural networks.

• Crooke-Rosado JL*, Diaz-Mendez SC, Claudio-Roman YE, Rivera NM, Sosa MA (2021) De novo assembly of the freshwater prawn Macrobrachium carcinus brain transcriptome for identification of potential targets for antybody and in situ probe development. Plos ONE D-21-00863, pending minor revisions.
• Colón-Cruz L*, Kristofco L, Crooke-Rosado J*, Acevedo A*, Torrado A, Brooks BW, Sosa MA, Behra M (2018) Alterations of larval photo-dependent swimming responses (PDR): New endpoints for rapid and diagnostic screening of aquatic contamination. Ecotoxicol Environ Saf. Jan;147:670-680. doi: 10.1016/j.ecoenv.2017.09.018. PMID: 28934711
• Bravo-Rivera C, Diaz-Ríos M, Aldarondo-Hernández A, Santos-Vera B, Ramos-Medina L, De Jesús-Burgos MI, Bravo-Rivera H*, Torrado A, Cabezas-Bou E, Cruz-Lopez F, Colón-Mercado J, Otero-Rivera J, Rolon-Reyes K, Mendez-Gonzalez M, Ferrer-Acosta Y, Zayas-Santiago A, Tejeda F, Merced A, Quintero-Martinez Z, Landivar A, Colon-Cruz Luis*, Crooke-Rosado J*, Rivera-Aponte D, Acevedo-Canabal A*, Sosa-Lloréns M, Quijano-Rivera,Eduardo (2018) NeuroBoricuas: a novel approach for incorporating neuroscience education in schools of Puerto Rico. 4th International Conference on Higher Education Advances (HEAd’18), Universitat Politecnica de Valencia, Valencia, DOI: http://dx.doi.org/10.4995/HEAd18.2018.8223
•  Ortiz-Colón AI*, Piñero LE, Rivera NM, Sosa MA (2016) Assessment of concentrations of heavy metals and phthalates in two urban rivers of the Northeast of Puerto Rico. J Environ Anal Toxicol, 6:2 pii: 1000353
• Jezzini SH, Reyes-Colón D, Sosa MA (2014) Characterization of a prawn OA/TA receptor in Xenopus oocytes suggests functional selectivity between octopamine and tyramine. PLOS One, Oct 28;9(10):e111314. doi: 10.1371/journal.pone.0111314. PMID:25350749
• Reyes-Colón D, Vázquez-Acevedo N, Rivera NM, Jezzini S, Rosenthal J, Ruiz-Rodriguez EA, Baro DJ, Kohn A, Moroz L, Sosa MA (2010) Cloning and distribution of a putative octopamine/tyramine receptor in the central nervous system of the freshwater prawn Macrobrachium rosenbergii. Brain Res. 1348:42-54. PMID: 20558147
• Vázquez-Acevedo N, Rivera NM, Torres-González AM, Rullan-Matheu Y, Ruíz-Rodríguez EA, Sosa MA (2009) GYRKPPFNGSIFamide (Gly-SIFamide) modulates aggression in the freshwater prawn Macrobrachium rosenbergii. Biol Bull. 217(3):313-326. PMID: 20040755
• Vázquez-Acevedo N, Reyes-Colón D, Ruiz-Rodríguez EA, Rivera NM, Rosenthal J, Kohn AB, Moroz LL, Sosa MA (2009) Cloning and immunoreactivity of the 5-HT1Mac and 5-HT2Mac receptors in the central nervous system of the freshwater prawn Macrobrachium rosenbergii. J Comp Neurol 513(4):399-416.
• Sosa MA, Spitzer N, Edwards DH, Baro DJ. (2004) A crustacean serotonin receptor: Cloning and distribution in the thoracic ganglia of crayfish and freshwater prawn. J Comp Neurol, 473: 526-537.
• Clark MC, Dever TE, Dever JJ, Xu P, Rehder V, Sosa MA, Baro DJ (2004). Arthropod 5-HT2 receptors: A neurohormonal receptor in Decapod crustaceans that displays agonist independent activity resulting from an evolutionary alteration of the DRY motif. J Neurosci, 24:3421-3435.
• Sosa MA, Baro DJ (2002) Amine effects on aggression in the giant tropical freshwater prawn Macrobrachium rosenbergii. In: The Crustacean Nervous System, (K. Wiese, ed.). Springer-Verlag Berlin-Heidelberg, pp. 143-155.
• Perez Nivia L, Sosa MA, Kuffler DP (1997) Growth cones turn up concentration gradients of diffusible peripheral target-derived factors. J. Exp. Neurol., 145:196-202.
• Blagburn JM, Sosa MA, Blanco RE (1996) Specificity of identified central synapses in the embryonic cockroach: appropriate connections form before the onset of spontaneous afferent activity. J. Comp. Neurol., 373:511-528.
• Sosa MA, Blagburn JM (1995) Competitive interactions between supernumerary and normal sensory neurons in the cockroach are mediated through a change in quantal content and not quantal size.  J.  Neurophysiol., 104(4):1573-1582.
• Zengel JE, Sosa MA, Poage RE, Mosier DR (1994) Role of intracellular Ca2+ in stimulation-induced increases in transmitter release at the frog neuromuscular junction.  J.  Gen.  Physiol., 104(2):337-355.
• Zengel JE, Sosa MA (1994) Changes in MEPP frequency during depression of evoked release at the frog neuromuscular junction. J. Physiol. (London), 477.2:267-277.
• Zengel JE, Lee DT, Sosa MA, Mosier DR (1993) Effects of calcium channel blockers on stimulation-induced changes in transmitter release at the frog neuromuscular junction. Synapse, 15:251-262.
• Sosa MA, Zengel JE (1993) Effect of glycerol treatment on transmitter release at the frog neuromuscular junction. Brain Res., 621:17-24.
• Sosa MA, Zengel JE (1993) Use of mu-conotoxin GIIIA for the study of synaptic transmission at the frog neuromuscular junction. Neurosci. Lett., 157(1-2):235-238.
• Zengel JE, Sosa MA, Poage RE (1993) Omega-conotoxin reduces facilitation of transmitter release at the frog neuromuscular junction. Brain Res., 611:25-30.