Expansion of CD4(+) CD25(+) Foxp3(+) T cells by bone marrow-derived dendritic cells

Dendritic cells (DCs) are the most important antigen-presenting cells of the immune system and have a crucial role in T-lymphocyte activation and adaptive immunity initiation. However, DCs have also been implicated in maintaining immunological tolerance. In this study, we evaluated changes in the CD4(+) CD25(+) Foxp3(+) T-cell population after co-culture of lymph node cells from BALB/c mice with syngeneic bone marrow-derived DCs. Our results showed an increase in CD4(+) CD25(+) Foxp3(+) T cells after co-culture which occurred regardless of the activation state of DCs and the presence of allogeneic apoptotic cells; however, it was greater when DCs were immature and were pulsed with the alloantigen. Interestingly, syngeneic apoptotic thymocytes were not as efficient as allogeneic apoptotic cells in expanding the CD4(+) CD25(+) Foxp3(+) T-cell population. In all experimental settings, DCs produced high amounts of transforming growth factor (TGF)-beta. The presence of allogeneic apoptotic cells induced interleukin (IL)-2 production in immature and mature DC cultures. This cytokine was also detected in the supernatants under all experimental conditions and enhanced when immature DCs were pulsed with the alloantigen. CD4(+) CD25(+) Foxp3(+) T-cell expansion during co-culture of lymph node cells with DCs strongly suggested that the presence of alloantigen enhanced the number of regulatory T cells (Tregs) in vitro. Our data also suggest a role for both TGF-beta and IL-2 in the augmentation of the CD4(+) CD25(+) Foxp3(+) population.

An unusual, dwarf new species of Neotropical freshwater stingray, Plesiotrygon nana sp. nov., from the upper and mid Amazon basin: the second species of Plesiotrygon (Chondrichthyes: Potamotrygonidae)

A new species of the relatively poorly known Neotropical freshwater stingray genus Plesiotrygon Rosa, Castello & Thorson, 1987 is described from the main channel and smaller tributaries (Ríos Itaya and Pachitea) of the upper Amazon basin in Peru. The first specimen to be collected, however, was from much farther east in Rio Solimões in 1996, just down-river from Rio Purus (specimen unavailable for this study). Plesiotrygon nana sp. nov., is a very distinctive and unusually small species of freshwater stingray (Potamotrygonidae), described here mostly from three specimens representing different size classes and stages of sexual maturity. Plesiotrygon nana sp. nov., is distinguished from its only congener, P. iwamae Rosa, Castello & Thorson, 1987, by numerous unique features, including: dorsal coloration composed of very fine rosettes or a combination of spots and irregular ocelli; very circular disc and snout; very small and less rhomboidal spiracles; short snout and anterior disc region; narrow mouth and nostrils; denticles on dorsal tail small, scattered, not forming row of enlarged spines; adult and preadult specimens with significantly fewer tooth rows; fewer caudal vertebrae; higher total pectoral radials; very small size, probably not surpassing 250 mm disc length or width, males maturing sexually at around 180 mm disc length and 175 mm disc width; distal coloration of tail posterior to caudal stings usually dark purplish-brown; and features of the ventral lateral-line canals (hyomandibular canal very narrow, infraorbital and supraorbital canals not undulated, supraorbital and infraorbital loops small and narrow, supraorbital loop very short, not extending posteriorly to level of mouth, jugular and posterior infraorbital canals short, not extending caudally to first gill slits, subpleural loop very narrow posteriorly; absence of anterior and posterior subpleural tubules). To provide a foundation for the description of P. nana sp. nov., morphological variation in P. iwamae was examined based on all type specimens as well as newly collected and previously unreported material. Two specimens topotypic with the male paratype of P. nana sp. nov., referred to here as Plesiotrygon cf. iwamae, are also reported. Relationships of the new species to P. iwamae are discussed; further characters indicative of Plesiotrygon monophyly are proposed, but the genus may still not be valid. Plesiotrygon nana sp. nov., is commercialized with some regularity in the international aquarium trade from Iquitos (Peru), an alarming circumstance because nothing is known of its biology or conservation requirements.

A new species of Neotropical freshwater stingray of the genus Potamotrygon Garman, 1877 from the Río Madrede Díos, Peru (Chondrichthyes: Potamotrygonidae)

Potamotrygon tatianae sp. nov., is described from Río Madre de Díos, Peru, upper Rio Madeira basin. The new species is distinguished from all congeners by a unique combination of characters, including its dorsal color pattern formed by a relatively slender, highly convoluted, beige to dark brown vermicular pattern, a single row of dorsal tail spines, and a relatively longer tail posterior to caudal stings. Potamotrygon tatianae sp. nov., occurs sympatrically with other species of Potamotrygon (P. falkneri, P. orbignyi and P. motoro). From the similar species P. falkneri, P. tatianae sp. nov., is further distinguished by the absence of circular, reniform, and oval spots, by its proportionally much longer tail, by having dorsal tail spines in one irregular row, and by features of the ventral lateral-line canal, dermal denticles and neurocranium. From P. orbignyi, the new species is distinct by lacking a reticulate pattern on dorsal disc and by the presence of two angular cartilages. From P. motoro, P. tatianae sp. nov., is further separated by the lack of ocelli formed by strong black concentric rings, by the more flattened aspect of its head and disc, and by having smaller and more numerous teeth. The discovery of a new species that so closely resembles a congeneric form in color pattern, a feature highly variable within the latter, highlights the importance of examining large series of individuals and of detailed morphological analyses in revealing the potentially highly cryptic nature of the diversity within the family.

A new genus and a new species of Clausiidae (Crustacea, Copepoda) parasitic on Dipolydora armata (Polychaeta, Spionidae) in Brazil

A new genus and species of parasitic copepod (Clausiidae), Spionicola mystaceus, associated with the polychaete Dipolydora armata (Spionidae) is described and figured. The new copepod has an elongate body, 5-segmented antennule, 2-segmented rami on legs 1 and 2, 2 spines representing leg 3, no leg 4, leg 5 well developed and reduced armature elements on feeding limbs. The host is a mollusk-shell borer, collected off São Sebastião Island, State of São Paulo, Brazil.

A new species of Trichogenes from the rio Itapemirim drainage, southeastern Brazil, with comments on the monophyly of the genus (Siluriformes: Trichomycteridae)

A new species of the formerly monotypic genus Trichogenes is described from a high-altitude stream of the rio Itapemirim system, an isolated Atlantic drainage in the State of Espírito Santo, southeastern Brazil. Trichogenes claviger, new species, differs from all other trichomycterids by the sexually dimorphic posterior process of the opercle, much elongated in males; the terminal mouth; the deeply bifurcated anterior neural spines and the presence of a large anterodorsal claw-like process on the neural arches of the anterior four free vertebrae. The new species also differs from its only congener, T. longipinnis, by a number of additional traits, including the the lack of branched anal-fin rays in specimens of any size; the broader than long posterior nostril; the deeper head (head depth 72.9-86.6% HL); the presence of a fine dark line along the base of the anal fin; the lack of dark spots on cheeks; the shape of the interopercle; the presence of odontodes on a bony expansion on the posterodorsal margin of the interopercle; the fewer vertebrae (35); the absence of an antorbital; and the fewer pleural ribs (eight). Small juveniles of the new species are also strikingly different from those of all other Trichomycteridae, including T. longipinnis, having a very large lateral eye, an upturned mouth, and compressed head. Trichogenes claviger occurs in shaded sectors of a blackwater sluggish stream with sandy substrate and patchy accumulations of vegetable debris, a habitat markedly different from the rocky torrential environment known for T. longipinnis. A comparison of the internal anatomy of the two species provides the basis for a hypothesis of a monophyletic Trichogenes. Data from the new species further support a sister-group relationship between Trichogeninae and Copionodontinae, as well as the position of that clade as sister group to all remaining Trichomycteridae.

Redescription of Hanleya brachyplax (Polyplacophora, Hanleyidae) from the south-southeastern Brazilian coast

Hanleya brachyplax Simone & Jardim in Rios, 2009 is described in detail. The species occurs off the southeastern and south coast of Brazil (São Paulo and Santa Catarina states) in depths from 250 to 408 m. It differs from its congeners in having uniform white valves; wide intermediate valves; the tail valve with straight profile in the antemucronal area, and a concave postmucronal surface; and a cream-colored girdle, covered by non-articulated spines. An anatomical investigation was also performed, showing the main muscle groups; the presence of gills in the posterior third of the pallial groove; auricle with six orifices; a very flat kidney, restricted to the posterior half of the animal; and a simple esophageal region. The odontophore has a single pair of long cartilages. The buccal musculature is also described.

A new species of Baurusuchus (Crocodyliformes, Mesoeucrocodylia) from the Upper Cretaceous of Brazil, with the first complete postcranial skeleton described for the family Baurusuchidae

The present work describes a new species of Baurusuchidae from Upper Cretaceous sediments of the Bauru Basin, and provides the first complete postcranial description for the family. Many postcranial features observed in the new species are also present in other notosuchian taxa, and are thus considered plesiomorphic for the genus. These are: long cervical neural spines; robust deltopectoral crest of the humerus; large proximal portion in the radiale that contacts the ulna; ulnare anterior distal projection; supra-acetabular crest well developed laterally; post-acetabular process posterodorsally deflected; presence of an anteromedial crest in the femur; fourth trocanter of femur posteriorly positioned; tibia with a laterally curved shaft; calcaneum tuber posteroventrally oriented; osteoderms ornamented with grooves and imbricated in the tail. On the other hand, we found the following sacral and carpal features to be unique among all mesoeucrocodylians analyzed: transverse processes of sacral vertebrae dorsolaterally deflected; presence of a longitudinal crest in the lateral surface of sacral vertebrae; pisiform carpal with a condyle-like surface. The majority of these cited features corroborates a cursorial locomotion for the new species described in the present study, suggesting that members of the family Baurusuchidae were also cursorial species.

Cinco novas espécies de Cerambycidae (Insecta: Coleoptera) da Região Neotropical e novos registros

New species are described: Tessaropa elongata sp. nov. from Brazil (Rondônia) has long elytra, a character that distinguishes it from the remaining species with short elytra; Hexoplon immaculatum sp. nov. from Ecuador (Pichincha) is characterized by the red-orange general color and black legs. Eburodacrys inaequalis sp. nov. from Bolivia (Santa Cruz) has elytral apices and same-color femora that cause it to be similar to E. ayri Martins & Galileo, 2006 and E. silviamariae Martins & Galileo, 2006, yet it differs from either species in the black lateral spines and dorsal tubercles of pronotum and the elongate eburneuos maculae of the elytra. Coleomethia bezarki sp. nov. (Costa Rica, Guanacaste) differs from C. australis Hovore, 1987 by male pronotum without rugosities, peduculate metafemora and metatibiae entirely pubescent. Bisaltes (B.) petilus sp. nov. (Costa Rica, Guanacaste, Alajuela) is separated from B. (B.)buquetii Thomson, 1868 and B. (B.) fuchsi Breuning, 1971 by the more slender body appearance, the absence of dark belts on pronotum, and the absence of circular macula in the anterior third of elytra. Notes and new records are provided for: Tetraibion concolor Martins, 2006 (Bolivia: La Paz); Gnomidolon ornaticolle Martins, 1960 (Panama: Colón); Mephritus apicatus (Linsley, 1935) (Brazil: Rondônia).

Description of Micropygomyia brandaoi sp. n. (Diptera: Psychodidae: Phlebotominae), a fossil phlebotomine from the Dominican Republic

The description of Micropygomyia brandaoi, a new species of fossil phlebotomine sand fly, is based on one male specimen obtained from Dominican amber of the Miocene period (20 million years). In this new species, the fifth palpal segment is long, the coxite lacks a setal tuft and the style shows four well-developed spines. This set of characters allowed us to place the new species in the genus Micropygomyia Barretto.

Description of micropygomyia brandaoi sp. N. (diptera: psychodidae: phlebotominae), a fossil phlebotomine from the Dominican Republic

The description of Micropygomyia brandaoi, a new species of fossil phlebotomine sand fly, is based on one male specimen obtained from Dominican amber of the Miocene period (20 million years). In this new species, the fifth palpal segment is long, the coxite lacks a setal tuft and the style shows four well-developed spines. This set of characters allowed us to place the new species in the genus Micropygomyia Barretto

Review of American fossil phlebotominae (Diptera: Psychodidae) with a description of two new species

The objective of this study was to carry out a taxonomic review of fossil American phlebotomine sand flies and describe two new species found in amber in the Dominican Republic. The gonostyle of one of these, Micropygomyia dorafeliciangeliae nov. sp., (=Lutzomyia dorafeliciangeliae, species group oswaldoi), has five spines, similar to that of Micropygomyia paterna (Quate, 1963) (= Lutzomyia paterna, species group oswaldoi), but they may be distinguished by the alpha/gamma ratio, which is <1.0 in the new species and >1 in the latter. Pintomyia dominicana nov. sp. (=Lutzomyia dominicana, species group verrucarum) has four spines on the gonostyle and presents a long bristle on the apex of the paramere, which distinguishes it from the other fossil species. With the description of these two new species, a total of 14 species of the American fossil phlebotomine sand flies has been described, 10 of which belong to the genus Pintomyia. An identification key for male fossil species is presented

Embryonic, Larval, and Juvenile Development of the Sea Biscuit Clypeaster subdepressus (Echinodermata: Clypeasteroida)

Sea biscuits and sand dollars diverged from other irregular echinoids approximately 55 million years ago and rapidly dispersed to oceans worldwide. A series of morphological changes were associated with the occupation of sand beds such as flattening of the body, shortening of primary spines, multiplication of podia, and retention of the lantern of Aristotle into adulthood. To investigate the developmental basis of such morphological changes we documented the ontogeny of Clypeaster subdepressus. We obtained gametes from adult specimens by KCl injection and raised the embryos at 26 degrees C. Ciliated blastulae hatched 7.5 h after sperm entry. During gastrulation the archenteron elongated continuously while ectodermal red-pigmented cells migrated synchronously to the apical plate. Pluteus larvae began to feed in 3 d and were similar to 20 d old at metamorphosis; starved larvae died 17 d after fertilization. Postlarval juveniles had neither mouth nor anus nor plates on the aboral side, except for the remnants of larval spicules, but their bilateral symmetry became evident after the resorption of larval tissues. Ossicles of the lantern were present and organized in 5 groups. Each group had 1 tooth, 2 demipyramids, and 2 epiphyses with a rotula in between. Early appendages consisted of 15 spines, 15 podia (2 types), and 5 sphaeridia. Podial types were distributed in accordance to Loven's rule and the first podium of each ambulacrum was not encircled by the skeleton. Seven days after metamorphosis juveniles began to feed by rasping sand grains with the lantern. Juveniles survived in laboratory cultures for similar to 9 months and died with <500 mu m wide, a single open sphaeridium per ambulacrum, aboral anus, and no differentiated food grooves or petaloids. Tracking the morphogenesis of early juveniles is a necessary step to elucidate the developmental mechanisms of echinoid growth and important groundwork to clarify homologies between irregular urchins.

Plasmodium vivax: Induction of CD4(+)CD25(+)FoxP3(+) Regulatory T Cells during Infection Are Directly Associated with Level of Circulating Parasites

Circulation CD4(+)CD25(+)FoxP3(+) regulatory T cells (Tregs) have been associated with the delicate balancing between control of overwhelming acute malaria infection and prevention of immune pathology due to disproportionate inflammatory responses to erythrocytic stage of the parasite. While the role of Tregs has been well-documented in murine models and P. falciparum infection, the phenotype and function of Tregs in P. vivax infection is still poorly characterized. In the current study, we demonstrated that patients with acute P. vivax infection presented a significant augmentation of circulating Tregs producing anti-inflammatory (IL-10 and TGF-beta) as well as pro-inflammatory (IFN-gamma, IL-17) cytokines, which was further positively correlated with parasite burden. Surface expression of GITR molecule and intracellular expression of CTLA-4 were significantly upregulated in Tregs from infected donors, presenting also a positive association between either absolute numbers of CD4(+)CD25(+)FoxP3(+)GITR(+) or CD4(+)CD25(+)FoxP3(+)CTLA-4(+) and parasite load. Finally, we demonstrate a suppressive effect of Treg cells in specific T cell proliferative responses of P. vivax infected subjects after antigen stimulation with Pv-AMA-1. Our findings indicate that malaria vivax infection lead to an increased number of activated Treg cells that are highly associated with parasite load, which probably exert an important contribution to the modulation of immune responses during P. vivax infection.

Bronchus-Associated Lymphoid Tissue (BALT) and Survival in a Vaccine Mouse Model of Tularemia

Background: Francisella tularensis causes severe pulmonary disease, and nasal vaccination could be the ideal measure to effectively prevent it. Nevertheless, the efficacy of this type of vaccine is influenced by the lack of an effective mucosal adjuvant. Methodology/Principal Findings: Mice were immunized via the nasal route with lipopolysaccharide isolated from F. tularensis and neisserial recombinant PorB as an adjuvant candidate. Then, mice were challenged via the same route with the F. tularensis attenuated live vaccine strain (LVS). Mouse survival and analysis of a number of immune parameters were conducted following intranasal challenge. Vaccination induced a systemic antibody response and 70% of mice were protected from challenge as showed by their improved survival and weight regain. Lungs from mice recovering from infection presented prominent lymphoid aggregates in peribronchial and perivascular areas, consistent with the location of bronchus-associated lymphoid tissue (BALT). BALT areas contained proliferating B and T cells, germinal centers, T cell infiltrates, dendritic cells (DCs). We also observed local production of antibody generating cells and homeostatic chemokines in BALT areas. Conclusions: These data indicate that PorB might be an optimal adjuvant candidate for improving the protective effect of F. tularensis antigens. The presence of BALT induced after intranasal challenge in vaccinated mice might play a role in regulation of local immunity and long-term protection, but more work is needed to elucidate mechanisms that lead to its formation.

Active Dendrites Enhance Neuronal Dynamic Range

Since the first experimental evidences of active conductances in dendrites, most neurons have been shown to exhibit dendritic excitability through the expression of a variety of voltage-gated ion channels. However, despite experimental and theoretical efforts undertaken in the past decades, the role of this excitability for some kind of dendritic computation has remained elusive. Here we show that, owing to very general properties of excitable media, the average output of a model of an active dendritic tree is a highly non-linear function of its afferent rate, attaining extremely large dynamic ranges (above 50 dB). Moreover, the model yields double-sigmoid response functions as experimentally observed in retinal ganglion cells. We claim that enhancement of dynamic range is the primary functional role of active dendritic conductances. We predict that neurons with larger dendritic trees should have larger dynamic range and that blocking of active conductances should lead to a decrease in dynamic range.