Discovery of a novel symbiotic lineage associated with a hematophagous leech from the genus Haementeria.

Similarly to other strict blood feeders, leeches from the Haementeria genus (Hirudinida: Glossiphoniidae) have established a symbiotic association with bacteria harbored intracellularly in esophageal bacteriomes. Previous genome sequence analyses of these endosymbionts revealed co-divergence with their hosts, a strong genome reduction, and a simplified metabolism largely dedicated to the production of B vitamins, which are nutrients lacking from a blood diet. 'Candidatus Providencia siddallii' has been identified as the obligate nutritional endosymbiont of a monophyletic clade of Mexican and South American Haementeria spp. However, the Haementeria genus includes a sister clade of congeners from Central and South America, where the presence or absence of the aforementioned symbiont taxon remains unknown. In this work, we report on a novel bacterial endosymbiont found in a representative from this Haementeria clade. We found that this symbiont lineage has evolved from within the Pluralibacter genus, known mainly from clinical but also environmental strains. Similarly to Ca. Providencia siddallii, the Haementeria-associated Pluralibacter symbiont displays clear signs of genome reduction, accompanied by an A+T-biased sequence composition. Genomic analysis of its metabolic potential revealed a retention of pathways related to B vitamin biosynthesis, supporting its role as a nutritional endosymbiont. Finally, comparative genomics of both Haementeria symbiont lineages suggests that an ancient Providencia symbiont was likely replaced by the novel Pluralibacter one, thus constituting the first reported case of nutritional symbiont replacement in a leech without morphological changes in the bacteriome. IMPORTANCE: Obligate symbiotic associations with a nutritional base have likely evolved more than once in strict blood-feeding leeches. Unlike those symbioses found in hematophagous arthropods, the nature, identity, and evolutionary history of these remains poorly studied. In this work, we further explored obligate nutritional associations between Haementeria leeches and their microbial symbionts, which led to the unexpected discovery of a novel symbiosis with a member of the Pluralibacter genus. When compared to Providencia siddallii, an obligate nutritional symbiont of other Haementeria leeches, this novel bacterial symbiont shows convergent retention of the metabolic pathways involved in B vitamin biosynthesis. Moreover, the genomic characteristics of this Pluralibacter symbiont suggest a more recent association than that of Pr. siddallii and Haementeria. We conclude that the once-thought stable associations between blood-feeding Glossiphoniidae and their symbionts (i.e., one bacteriome structure, one symbiont lineage) can break down, mirroring symbiont turnover observed in various arthropod lineages.

Unoculubranchiobdella sp. (Hirudinea: Ozobranchidae) as a vector for Haemogregarina spp. in freshwater turtles from Brazil.

Species of Haemogregarina are blood parasites known to parasitise vertebrate hosts, including fishes (Haemogregarina sensu lato) and freshwater turtles (Haemogregarina sensu stricto). Their vectors, include gnathiid isopods and leeches, respectively. In turtles, Haemogregarina balli has the best-characterized life cycle in the genus. However, no studies in Brazil have suggested a possible vector for any species of Haemogregarina from freshwater turtles. Therefore, in the present study, we provide insights into a leech vector based on specimens found feeding on two species of freshwater turtles, Podocnemis unifilis and Podocnemis expansa, using morphological and molecular data. In 2017 and 2019, freshwater turtles were collected in Goiás State, Brazil. Hosts were inspected for ectoparasites and leeches were collected from two specimens of P. expansa and nine specimens of P. unifilis. Leeches were subsequently identified as members of the genus Unoculubranchiobdella. Leech histological slides revealed haemogregarine-like structures, similar to post-sporogonic merogony, found near the gills and within the posterior sucker. Molecular analysis of the haemeogregarines resulted in the identification of three species of Haemogregarina: Haemogregarina embaubali, Haemogregarina goianensis, and Haemogregarina brasiliana. Therefore, our findings, based on morphology and DNA data suggest leeches of the genus Unoculubranchiondella as vectors for at least three species of Haemogregarina from Brazilian turtles.

Occurrence of parasitism promoted by Myzobdella lugubris Leidy, 1851 (Annelida: Piscicolidae) in Callinectes bocourti (Crustacea: Portunidae): A report of invasive leech in Brazilian Amazon province.

This study reports the presence of high parasitic load by Myzobdella lugubris Leidy, 1851 in the swimming crab Callinectes bocourti A. Milne-Edwards, 1879 from Amazon mangrove. We sampled the swimming crabs using a baited trap, between January and June 2023, in Santa Maria River, located in the municipality of Curuçá, state of Pará, Brazil (geographical coordinates 0°40'3.705"S, 047°54'43.405"W). After sampling, each swimming crab was individually placed in plastic containers for the count of leeches per individual. In the laboratory, the specimens were sexed, measured (parasite and host) and fixed in 70% alcohol. For the leech species identification, macroscopic techniques were combined with light microscopy (LM) and scanning electron microscopy (SEM). We examined 86 specimens of C. bocourti (75 males and 11 females) in a ratio of 1 M:0.14 F, all infested with leeches. In total, 186 leech specimens were collected, ranging from 1 to 21 leeches per host. Leeches oviposited the cocoons in greater quantities in ventral area of swimming crab carapace (32%), followed by dorsal area of carapace (29.09%), chelipeds (24.34%) and ambulatory legs (14.57%). The presence of M. lugubris is a risk to the health of the host, once it may transmit a range of diseases to aquatic organisms, and subsequently risk to human health.

Not that many leech species after all: Myzobdella lugubris and Myzobdella patzcuarensis (Annelida: Hirudinida) are the same species.

The genus Myzobdella groups five species of leeches parasites of fishes mainly of freshwater but with tolerance to brackish waters. Native distribution of these species includes the New World from North to South America. Myzobdella lugubris Leidy, 1851, the type species of the genus, was briefly described based on specimens from the USA, but subsequently their morphology, known distribution and host range were expanded; however, less is known about the other four species of the genus. As part of a survey focusing on characterizing the diversity of leeches from Mexico, specimens of Myzobdella patzcuarensis (Caballero, 1940), from the type locality of the species were included for the first time in a phylogenetic study. In addition, specimens assigned to Myzobdella from the southeast of Mexico as well as from Nicaragua, were also included. In the resulting phylogenetic tree, our newly generated sequences were found nested in the same clade that M. lugubris; with unresolved relationships and relatively low genetic divergence, suggesting conspecificity. In addition, the internal morphology of the specimens of Myzobdella from Mexico is consistent with the description of M. lugubris. Our morphological examination reveals high degrees of variability in the external pigmentation of the specimens. Based on our results we formally synonymize M. patzcuarensis under M. lugubris.

MOLECULAR PHYLOGENY OF THE LEECH GENUS PONTOBDELLA (HIRUDINIDA: PISCICOLIDAE) WITH NOTES ON PONTOBDELLA CALIFORNIANA AND PONTOBDELLA MACROTHELA.

Leech specimens of the genus Pontobdella (Hirudinida: Piscicolidae) were found off the coast of the state of Oaxaca (Pacific) as well as in Veracruz and Tabasco (Gulf of Mexico), Mexico. Based on the specimens collected in Oaxaca, a redescription of Pontobdella californiana is provided, with emphasis on the differences in the reproductive organs with the original description of the species. In addition, leech cocoons assigned to P. californiana were found attached to items hauled by gillnets and studied using scanning electron microscopy and molecular approaches. Samples of Pontobdella macrothela were found in both Pacific and Atlantic oceans, representing new geographic records. The phylogenetic position of P. californiana is investigated for the first time, and with the addition of Mexican samples of both species, the phylogenetic relationships within Pontobdella are reinvestigated. Parsimony and maximum-likelihood phylogenetic analysis were based on mitochondrial (cytochrome oxidase subunit I [COI] and 12S rRNA) and nuclear (18S rRNA and 28S rRNA) DNA sequences. Based on our results, we confirm the monophyly of Pontobdella and the pantropical distribution of P. macrothela with a new record in the Tropical Eastern Pacific.

Composition and structure of the parasitic fauna of Hypostomus spp. (Loricariidae: Hypostominae) from a Neotropical river in Brazil.

Hypostomus are abundant in Brazilian rivers and streams. In the Ivaí River, the loricariids represent 20.3% of the total species of the basin. Of these 13 species belong to Hypostomus. However, to date, there are no studies on these fish parasitic fauna. Thus, this research aimed to analyze the distribution of the parasitic infracommunity of six species of Hypostomus from the Ivaí River and investigate how the infracommunity is structured in these hosts. One hundred and twenty-eight fish were analyzed, belonging to six sympatric species of Hypostomus (Hypostomus hermanni, H. cochliodon, H. albopunctatus, H. regani, Hypostomus sp.1, and Hypostomus sp.2); of these, 92.9% were parasitized with at least one taxon, totaling 1478 specimens of parasites. The parasitic fauna was composed of the ectoparasites Trinigyrus anthus, T. carvalhoi, Unilatus unilatus (monogeneans), and Placobdella spp. (hirudinea), and the endoparasites Austrodiplostomum compactum (digenean) and Procamallanus annipetterae (nematode). The parasites exhibited similar patterns of infection in all hosts, including a low number of species, low diversity, and numerical dominance of a group of parasites. However, permutational multivariate analysis of variance (PERMANOVA) showed different parasite species compositions among the hosts. Hypostomus cochliodon and H. regani had the highest parasite richness, while Hypostomus sp.1 and Hypostomus sp.2 showed low abundance and intensity of parasitic infections. However, Hypostomus sp.1 showed the highest values of evenness, although the parasite composition in both species did not differ. The results presented herein contribute to increasing the knowledge about the parasitic fauna of Hypostomus spp. from the Ivaí River by presenting new hosts and locality records.

Metazoan endoparasites of Acestrorhynchus lacustris (Actinopterygii: Acestrorhynchidae) from lagoons bordering the upper and middle São Francisco river basin, Brazil.

The endoparasitic fauna of Acestrorhynchus lacustris from eight marginal lagoons of the upper and middle São Francisco river basin, Brazil, is recorded here for the first time. For this, a total of 106 specimens of A. lacustris were collected. Eighteen helminth species were found. The taxa recorded were phylum Platyhelminthes: one metacercaria of Clinostomum sp. (Trematoda: Clinostomidae) and plerocercoid larvae of unidentified species (Eucestoda: Proteocephalidae gen. sp.); phylum Acanthocephala: juvenile of Quadrigyrus sp.; and phylum Nematoda: larvae of Brevimulticaecum sp., Contracaecum sp. Type1, Contracaecum sp. Type2, Hysterothylacium sp., Gnathostoma sp., Spiroxys sp., juvenile and adult specimens of Freitascapillaria sp., Paracapillaria piscicola, Capillariidae gen. sp., Procamallanus (Spirocamallanus) hilarii, Procamallanus (S.) inopinatus, Procamallanus (S.) saofranciscencis, Travassosnema travassosi paranaensis, Cystidicoloides fischeri and Spinitectus rodolphiheringi. Proteocephalidae gen. sp., Contracaecum sp. Type1 and Travassosnema t. paranaensis were present in all eight lagoons with high parasitic indexes. Proteocephalidae gen. sp., Brevimulticaecum sp., Gnathostoma sp., Freitascapillaria sp., P. piscicola, Capillariidae gen. sp., Procamallanus (S.) hilarii, C. fischeri and S. rodolphiheringi are new records for A. lacustris. The known geographical distribution of Gnathostoma sp., Freitascapillaria sp., P. piscicola, Capillariidae gen. sp., Procamallanus (S.) hilarii and Travassosnema t. paranaensis has now been extended to the São Francisco river basin.

Intersegmental Interactions Give Rise to a Global Network.

Animal motor behaviors require the coordination of different body segments. Thus the activity of the networks that control each segment, which are distributed along the nerve cord, should be adequately matched in time. This temporal organization may depend on signals originated in the brain, the periphery or other segments. Here we evaluate the role of intersegmental interactions. Because of the relatively regular anatomy of leeches, the study of intersegmental coordination in these animals restricts the analysis to interactions among iterated units. We focused on crawling, a rhythmic locomotive behavior through which leeches move on solid ground. The motor pattern was studied ex vivo, in isolated ganglia and chains of three ganglia, and in vivo. Fictive crawling ex vivo (crawling) displayed rhythmic characteristics similar to those observed in vivo. Within the three-ganglion chains the motor output presented an anterior-posterior order, revealing the existence of a coordination mechanism that occurred in the absence of brain or peripheral signals. An experimental perturbation that reversibly abolished the motor pattern in isolated ganglia produced only a marginal effect on the motor activity recorded in three-ganglion chains. Therefore, the segmental central pattern generators present in each ganglion of the chain lost the autonomy observed in isolated ganglia, and constituted a global network that reduced the degrees of freedom of the system. However, the intersegmental phase lag in the three-ganglion chains was markedly longer than in vivo. This work suggests that intersegmental interactions operate as a backbone of correlated motor activity, but additional signals are required to enhance and speed coordination in the animal.

Novel Cysteine Protease Inhibitor Derived from the Haementeria vizottoi Leech: Recombinant Expression, Purification, and Characterization.

Cathepsin L (CatL) is a lysosomal cysteine protease primarily involved in the terminal degradation of intracellular and endocytosed proteins. More specifically, in humans, CatL has been implicated in cancer progression and metastasis, as well as coronary artery diseases and others. Given this, the search for potent CatL inhibitors is of great importance. In the search for new molecules to perform proteolytic activity regulation, salivary secretions from hematophagous animals have been an important source, as they present protease inhibitors that evolved to disable host proteases. Based on the transcriptome of the Haementeria vizzotoi leech, the cDNA of Cystatin-Hv was selected for this study. Cystatin-Hv was expressed in Pichia pastoris and purified by two chromatographic steps. The kinetic results using human CatL indicated that Cystatin-Hv, in its recombinant form, is a potent inhibitor of this protease, with a Ki value of 7.9 nM. Consequently, the present study describes, for the first time, the attainment and the biochemical characterization of a recombinant cystatin from leeches as a potent CatL inhibitor. While searching out for new molecules of therapeutic interest, this leech cystatin opens up possibilities for the future use of this molecule in studies involving cellular and in vivo models.

Testisacs microanatomy and spermatogenesis of Helobdella simplex (Hirudinida: Glossiphoniidae)

The aim of this study was to describe the testisac microanatomy and spermatogenesis of Helobdella simplex (Moore, 1911). The leeches were collected in the Sauce Chico River (Tornquist) during April 2012. The collection of material was carried out manually by checking rocks, logs, leaves and artificial substrates in the river bed. Helobdella simplex has six pairs of testisacs located between the gastric caeca. The testisac wall has two structurally and functionally differentiated cell types: the lining mesothelial cells and the germline cells. The lining cells are flat and form a continuous layer. In H. simplex no ciliated cells were observed into the testisacs, nor the formation of spermatogonia due to detachment of the testicular wall. Cell types were microscopically characterized, and five spermatogenesis stages are described, taking into account the maturation of germinal cells, the morphological changes in the cytophore and phagocytic activity. Testicular phagocytes actively participate during spermatogenesis. They are involved both in the removal of defective cells during the early stages of spermatogenesis and in the removal of the cytophore during the reacting reabsorption. Our study adds the knowledge of spermatogenesis in H. simplex and might be useful to differentiate the stages of development during the reproductive cycle, and to interpret aspects of its population dynamics.(AU)

Testisacs microanatomy and spermatogenesis of Helobdella simplex (Hirudinida: Glossiphoniidae)

The aim of this study was to describe the testisac microanatomy and spermatogenesis of Helobdella simplex (Moore, 1911). The leeches were collected in the Sauce Chico River (Tornquist) during April 2012. The collection of material was carried out manually by checking rocks, logs, leaves and artificial substrates in the river bed. Helobdella simplex has six pairs of testisacs located between the gastric caeca. The testisac wall has two structurally and functionally differentiated cell types: the lining mesothelial cells and the germline cells. The lining cells are flat and form a continuous layer. In H. simplex no ciliated cells were observed into the testisacs, nor the formation of spermatogonia due to detachment of the testicular wall. Cell types were microscopically characterized, and five spermatogenesis stages are described, taking into account the maturation of germinal cells, the morphological changes in the cytophore and phagocytic activity. Testicular phagocytes actively participate during spermatogenesis. They are involved both in the removal of defective cells during the early stages of spermatogenesis and in the removal of the cytophore during the reacting reabsorption. Our study adds the knowledge of spermatogenesis in H. simplex and might be useful to differentiate the stages of development during the reproductive cycle, and to interpret aspects of its population dynamics.(AU)

Phase-Specific Motor Efference during a Rhythmic Motor Pattern.

Neuronal circuits that control motor behaviors orchestrate multiple tasks, including the inhibition of self-generated sensory signals. In the hermaphroditic leech, T and P mechanosensory neurons respond to light touch and pressure on the skin, respectively. We show that the low threshold T cells were also sensitive to topological changes of the animal surface, caused by contraction of the muscles that erect the skin annuli. P cells were unresponsive to this movement. Annuli erection is part of the contraction phase of crawling, a leech locomotive behavior. In isolated ganglia, T cells showed phase-dependent IPSPs during dopamine-induced fictive crawling, whereas P cells were unaffected. The timing and magnitude of the T-IPSPs were highly correlated with the activity of the motoneurons excited during the contraction phase. Together, the results suggest that the central network responsible for crawling sends a reafferent signal onto the T cells, concomitant with the signal to the motoneurons. This reafference is specifically targeted at the sensory neurons that are affected by the movements; and it is behaviorally relevant as excitation of T cells affected the rhythmic motor pattern, probably acting upon the rhythmogenic circuit. Corollary discharge is a highly conserved function of motor systems throughout evolution, and we provide clear evidence of the specificity of its targets and timing and of the benefit of counteracting self-generated sensory input.SIGNIFICANCE STATEMENT Neuronal circuits that control motor behaviors orchestrate multiple tasks, including inhibition of sensory signals originated by the animal movement, a phenomenon known as corollary discharge. Leeches crawl on solid surfaces through a sequence of elongation and contraction movements. During the contraction, the skin topology changes, affecting a subpopulation of mechanosensory receptors, T (touch) neurons, but not P (pressure) sensory neurons. In the isolated nervous system, T neurons were inhibited during the contraction but not during the elongation phase, whereas P cells were unaffected throughout crawling. Excitation of T cells during the contraction phase temporarily disrupted the rhythmic pattern. Thus, corollary discharge was target (T vs P) and phase (contraction vs elongation) specific, and prevented self-generated signals to perturb motor behaviors.

Revascularización y reimplante digital. Revisión de conceptos actuales / Digital reimplantation adn revascularization. current concets

El reimplante es la obra maestra del cirujano de mano, donde incluye la técnica microquirúrgica para la anastomosis de arteria, vena y reparación del nervio, la osteosíntesis de los huesos y el manejo de tejidos blandos como los tendones y la piel Indicaciones absolutas, amputación del pulgar, el pulgar es quizás el elemento más importante de la mano, dado que le da funcionalidad a la extremidad, sin importar la movilidad final ni la sensibilidad debe reimplantarse el pulgar. No se debe intentar el reimplante en lesiones aplastantes de los dedos, amputación en más de un nivel, presencia de lesiones que amenacen la vida del paciente, enfermedades graves del paciente, isquemia prolongada, amputaciones en paciente con alteraciones psiquiátricas. Clasificación según Tamai es la mas utilizada. Se explica además como se debe transportar la parte amputada. La técnica microquirúrgica es lo mas importante para el desenlace. La rehabilitación física y posibles complicaciones.

Reimplantation is the masterpiece of the hand surgeon, which includes the microsurgical technique for artery anastomosis, vein and nerve repair, osteosynthesis of the bones and the management of soft tissues such as tendons and skin. Absolute indications, Amputation of the thumb: the thumb is perhaps the most important element of the hand because it gives functionality to the limb, regardless of the final mobility or sensitivity it should be reimplanted. Reimplantation should not be attempted in crushing lesions of the fingers. Crush injury of the fingers may have multilevel amputation and microcirculation injury that may not be susceptible of repair. Amputation at more than one level, the presence of life-threatening injuries, serious illnesses of the patient, prolonged ischemia, amputations in a patient with psychiatric disorders. Tamai Classification is the most used. We explain the correct way to transport the amputated part. The microsurgical technique is the most important in order to avoid complications. We also explain the physical therapy and complications.

A new species of Branchellion Savigny, 1822 (Hirudinida: Piscicolidae), a marine leech parasitic on the giant electric ray Narcine entemedor Jordan & Starks (Batoidea: Narcinidae) off Oaxaca, Mexico.

Branchellion spindolaorum n. sp. (Hirudinida: Piscicolidae) is described based on specimens found parasitising the giant electric ray Narcine entemedor Jordan & Starks off the coast of Oaxaca, Mexico. The new species can be clearly distinguished from the other species of Branchellion Savigny, 1822 by the presence of 30 pairs of lateral branchiae and 10 pairs of pulsatile vesicles. The definition of the genus Branchellion is expanded to include species with either 30, 31 or 33 pairs of foliaceous (plate-like) lateral branchiae in the urosome. In addition, we provide for the first time for the genus, scanning electron micrographs of the secondary suckers located on the ventral surface of the posterior sucker. Additionally, partial DNA sequences of the mitochondrial cytochrome c oxidase subunit 1 (cox1) were generated and compared with homologous sequences of other species of the genus. Branchellion spindolaorum n. sp. represents the fourth species of the genus known in the Eastern Pacific and the first record of a leech parasitising N. entemedor.

The salivary transcriptome of Limnobdella mexicana (Annelida: Clitellata: Praobdellidae) and orthology determination of major leech anticoagulants.

Bloodfeeding requires several adaptations that allow the parasite to feed efficiently. Leeches and other hematophagous animals have developed different mechanisms to inhibit hemostasis, one of the main barriers imposed by their hosts. Limnobdella mexicana is a member of the leech family Praobdellidae, a family of host generalists known for their preference to attach on mucosal membranes of mammals, such as those in nasopharyngeal cavities, bladders and ocular orbits. Previous studies have hypothesized a positive relationship between diversity of anticoagulants and diversity of hosts in bloodfeeding leeches. However, orthology determination of putative anticoagulants and the lack of standardization of sequencing effort and method hinder comparisons between publicly available transcriptomes generated in different laboratories. In the present study, we examine the first transcriptome of a praobdellid leech and identify 15 putative anticoagulants using a phylogeny-based inference approach, amino-acid conservation, Pfam domains and BLAST searches. Our phylogenetic analyses suggest that the ancestral leech was able to inhibit factor Xa and that some hirudins that have been reported in previous studies on leech anticoagulants may not be orthologous with the archetypal hirudin.

Leeches from Mexico City, remnants of the ancient lake.

Genetic barcodes (partial sequences of the mitochondrial cytochrome c oxidase subunit I) were generated for freshwater leeches that inhabit the Mexico Basin, upon which Mexico City and its metropolitan area have developed. Once a continuous lake, the basin has passed through continuous events of artificial desiccation in the last 500 years so that it is currently conformed by a few and highly modified and polluted isolated freshwater bodies. Six species of leeches from three families were collected in five localities. Current sequence databases were able to determine five of the six species collected for this study with the only exception of Haemopis caballeroi, for which no sequence data are available in public repositories. Taxonomic assignment of cocoons was possible via comparison of barcode sequences. We discuss the presence of a population of Erpobdella ochoterenai in Tecocomulco Lake that bares high genetic divergence from its conspecifics, which may indicate it is an undescribed species.

Unusual vaginal bleeding due to a leech bite in a girl from a tropical area: A case report.

This study describes the isolation of a leech following the presentation of unusual vaginal bleeding. Vaginal bleeding in children due to a leech bite is very rare. This is the first report of severe bleeding in a virgin 14-year-old girl from Mashhad, Iran due to the presence of a leech in the vagina.

Serotonin induces or inhibits neuritic regeneration of leech CNS neurons depending on neuronal identity.

Recovery of motor function after central nervous system (CNS) injury is dependent on the regeneration capacity of the nervous system, which is a multifactorial process influenced, among other things, by the role of neuromodulators such as serotonin. The neurotransmitter serotonin can promote neuronal regeneration but there are also reports of it causing restriction, so it is important to clarify these divergent findings in order to understand the direct scope and side effects of potential pharmacological treatments. We evaluated the effect of serotonin on the extent of neuritic outgrowth and morphology of three different neuronal types in the leech Haementeria officinalis during their regeneration in vitro: Retzius interneurons (Rz), annulus erector (AE) motoneurons, and anterolateral number 1 (AL1) CNS neurons. Neurons were isolated and cultured in L15 medium, with or without serotonin. Growth parameters were registered and quantified, and observed differences were analyzed. The addition of serotonin was found to induce AL1 neurons to increase their average growth dramatically by 8.3-fold (P=0.02; n=5), and to have no clear effect on AE motoneurons (P=0.44; n=5). For Rz interneurons, which normally do not regenerate their neurites, the addition of concanavaline-A causes substantial growth, which serotonin was found to inhibit on average by 98% (P=0.02; n=5). The number of primary neurites and their branches were also affected. These results reveal that depending on the neuronal type, serotonin can promote, inhibit, or have no effect on neuronal regeneration. This suggests that after CNS injury, non-specific pharmacological treatments affecting serotonin may have different effects on different neuronal populations.

Spatio-temporal variation and the use of host body surface by ectoparasites of the chelonians Phrynops geoffroanus and Mesoclemmys tuberculata in areas of the Caatinga and Atlantic Forest in northeast Brazil.

Ectoparasites such as hematophagous leeches and monogeneans are common in chelonians, occupying different parts of the body. Thus, the present study aimed to identify and describe the fauna of ectoparasites that infest Phrynops geoffroanus and Mesoclemmys tuberculata to evaluate the effect of host conditions and seasonality (dry and rainy season) on the abundance and composition of ectoparasites. We verified the presence of ectoparasites in 73.2% of the examined turtles, with four species of leeches belonging to Glossiphoniidae, Haementeria brasiliensis sensu Cordero, 1937, Helobdella cf. adiastola, Haementeria sp1., and Haementeria sp2., and one monogenean Polystomatidae, Polystomoides brasiliensis. For both chelonians, we observed a significant difference in the abundance of ectoparasites in relation to sex, biome, and season, which was unrelated to length and mass. Leeches were more frequent in the cavities of the hind limbs in P. geoffroanus, and the anterior limbs of M. tuberculata. The general spatial niche overlap of ectoparasites was high, except for that of the monogenean P. brasiliensis, which did not overlap with those of other leech species. The present study is the first report of the presence of H. brasiliensis and P. brasiliensis parasitizing M. tuberculata, and Helobdella cf. adiastola in a phoretic relationship with P. geoffroanus and M. tuberculata. Finally, the differences in infestation levels may reflect ecological factors, differences in behavioral patterns of the hosts, and different anthropic alterations suffered in the Caatinga and Atlantic Forest biomes.