Ichthyoplankton from the pier area in Limón, Costa Rica

Four sampling stations were set 200-500 m off Limon Port, Costa Rica, at an average depth of 20 m. From October 1996 to May 1997 horizontal subsuperficial trawls were done for 12 minutes at a speed of about 2 Km/h, with a 1,000 microns plancton net. A total of 28 samples were processed and 104 physical-chemistry parameter measurements were taken. Average salinity was 30.1 +/- 3.7 and dissolved oxygen 6.9 +/- 0.6 mg l-1 reflecting good aeration throughout the sampling period. This suggests good mixture and a highly dynamic hydrography. Temperature showed no drastic variations (28.0 +/- 1.7 degrees C), possibly because of the constant mixing with shallow water. The highest larval counts were for November and early January and include families common to reefs and estuaries (Balistidae, Lutjanidae) and to coastal areas (Centropomidae, Gerreidae, Haemulidae, Carangidae, Engraulidae, Hemiramphidae, and representative Pleuronectiformes) existing in a common area.     

Physical-chemical features and determination of pesticides in the lagoon water in Gandoca, Limón, Costa Rica.

Nutrients and chlorophylls concentrations, as well as salinity, temperature and Secchi disk depth were determined from November 1999 to April 2000, at three stations and two depths, at Gandoca lagoon, Gandoca-Manzanillo National Wildlife Refuge, Limón, Costa Rica. Salinity profiles indicated that the lagoon was a salt wedge estuary with a partially mixed region near the mouth. No processes of eutrophication were found. The distribution and abundance of nutrients and chlorophylls showed a slight influence of continental water and water circulation patterns in the lagoon. A preliminary study was done in order to analyze the presence of 20 organochlorated and organophosphorated pesticides along the Gandoca lagoon in February 2000. None of the pesticides were detected by the analysis of residues from liquid-liquid extractions. The absence of the pesticides may be due to the fact that they did not reach the lagoon or, if they did, they were washed away by the strong rains during the sampling period.     

Ethnicity, gene flow, and population subdivision in Limón, Costa Rica

In this paper we examine the effects of ethnicity on the gene flow between two groups living in Limón, Costa Rica. Our main interest is to determine if ethnicity has acted as a barrier to the exchange of genes, and if the groups have remained distinct genetically. We report the admixture estimates, F(st) values, and inbreeding coefficients of the two samples. The data consist of blood samples and surnames obtained from 375 individuals. The subjects' two surnames were analyzed to determine the ethnicity of their parents (individuals carry their father's and mother's first surnames). We used the formula of Crow and Mange ([1965] Eugen Q 12:199-203) to compute F(t), F(n), and F(r) with the surnames. Admixture estimates were computed for both groups using the computer program ADMIX.PAS kindly provided by Jeffrey Long. The estimates for the Hispanic-Limonense group are M1 = 0.5866 European, M2 = 0.3383 Amerindian, and M3 = 0.0751 African ancestry. For the Afro-Limonense group, the admixture estimates indicate M1 = 0.1047 European, M2 = 0.1357 Amerindian, and M3 = 0.7595 African ancestry. The F(st) values are F(st) = 0.00558 for the Hispanic group and F(st) = 0.05137 for the Afro-Limonense group. These F(st) values indicate that the Afro-Limonense group has experienced more genetic drift than has the other group, possibly as a result of its long history of isolation in Costa Rica. Indeed, when plotted along a scaled eigenvector R matrix of Caribbean gene frequencies, the two Limonense groups did not cluster with each other. Thus we conclude that the two ethnic groups have remained distinct breeding populations.     

The mangrove and others vegetation associations in de Gandoca lagoon, Limón, Costa Rica

Six plant associations were identified at Gandoca Lagoon by photointerpretation and field verification: a) mangroves, b) palm trees swamp, and palm trees with Acrostichum aureum and A. danaefolium, c) mixed palm trees, d) very humid tropical rain forest, and e) tropical beach vegetation. The mangroves cover 12.5 ha surrounding the lagoon and extend 2 km up the Gandoca River. Rhizophora mangle (red mangrove) was the dominant species, with Avicennia germinans (black mangrove), Laguncularia racemosa (white mangrove) and Conocarpus erectus (buttonwood) also present. Moving inland the mangroves grade into a tropical rain forest. Gandoca, the largest and best preserved mangrove of Caribbean Costa Rica, tripled its area from 1976 to 2000. Possible causes include sedimentation and the Limón earthquake, which may have subside the lagoon area.     

Indentured migration and differential gender gene flow: the origin and evolution of the East-Indian community of Limón, Costa Rica

After the emancipation of African slaves in the Caribbean, the labor void left by out-migrating former slaves was filled by in-migrating indentured servants from prepartition India and China. In some areas of the Caribbean such as Trinidad, Suriname, and Guyana, the East-Indian migrants formed large communities. In this article, we report a study based on mtDNA and Y-chromosomal markers of a small East-Indian community from Limón, Costa Rica. The purpose of the project is to determine the place of origin in the Indian subcontinent of the ancestors of our group and the contributions to its gene pool through gene flow by members of other ethnic groups. Both Y-chromosome and mtDNA suggest that the Indo-Costa Ricans descend from migrants primarily from Central India. While both paternal and maternal markers indicate that this group is overwhelmingly of Indian origin, they also indicate that males and females of African, European, and Amerindian origin contributed to it differently. We discuss our results in the historical context of the virtual extinction of Amerindian Caribbean groups, the forced migration of African slaves to the Caribbean, and the gene flow between Amerindians, Europeans, East-Indians, and Africans that eventually produced the Caribbean's currently diverse gene pool.     

Spatial ecology and conservation of two sloth species in a cacao landscape in limón,Costa Rica

The spatial ecology of sloths was studied in an agricultural landscape in Limón Province, Costa Rica. Two sloth species, the three-toed sloth (Bradypus variegatus) and the two-toed sloth (Choloepus hoffmanni), actively used and traveled through a cacao agroforest and its contiguous living fence rows and riparian forests. This agroecosystem was embedded in an agricultural landscape dominated by banana and pineapple plantations and pastures with dispersed trees. The two-toed sloth (C. hoffmanni) was found in 101 tree species and used 34 for food; the three-toed sloth (B. variegatus) was found in 71 tree species and used 15 for food. Choice of preferred species differed between the two sloth species. Trees commonly used by sloths for food and/or refuge in the cacao agroforest included Erythrina poeppigiana, Cecropia obtusifolia, Leucaena leucocephala; in the living fence rows, Cordia alliodora, Erythrina poeppigiana, Ocotea sinuata and Trophis racemosa; in the riparian forests, Coussapoa villosa, Cecropia obtusifolia, Hura crepitans, Pterocarpus officinalis and Spondias mombin; and in the pastures with dispersed trees, Cordia alliodora, Coussapoa villosa, Erythrina poeppigiana, Ocotea sinuata and Hura crepitans. This study demonstrates the importance of the cacao agroforest as well as arboreal elements in other land uses in providing resources for sloth conservation in a larger agricultural landscape.     

Intestinal parasites in white-faced capuchin monkeys Cebus capucinus (Primates: Cebidae) inhabiting a protected area in the Limón province of Northeastern Costa Rica

Deforestation of tropical forests is threatening monkey biodiversity and their health status, dependent of an ecologically undisturbed area. To asses this relationship, we analyzed parasite occurrence in their intestines. The study was conducted at the Estación Biológica La Suerte (EBLS), Limón, Costa Rica. The group of white-faced capuchin monkeys (Cebus capucinus) was observed between March and December of 2006. A total of 75 feces samples were obtained. Once a sample was collected, the eaten plant type was identified to family and species level, and feces were processed in the laboratory to determine parasite incidence. Results showed that Moraceae was the most represented family in the samples. Among parasites, Strongyloides spp. and Acanthocephala were the most common. Positive prevalence of parasites was found similar and independent of sex and age of capuchin individuals. Microsporids were mainly reported in feces associated with Piperaceae. A low presence of these parasites was found in samples associated with Myrtaceae, with possible anti-parasite active components. The occurrence of parasites was relatively high in EBLS, when compared to other regions in Costa Rica. The higher occurrence of parasites observed in capuchins at EBLS may be due to the fact that this rain forest is surrounded by areas affected by human activities. We suggest the promotion of research in neotropical primates parasitology, for a better comprehension of the parasite-host relationship, and in a long term, being able to understand the ecosystems where they coexist, and consequently, preserve the biodiversity of the whole region.     

Área de Conservación Guanacaste,northwestern Costa Rica: Converting a tropical national park to conservation via biodevelopment

The ~30,000 hectare classical Costa Rican Parque Nacional Santa Rosa has used about 35 years and $107 million to be converted to the 169,000 ha government-NGO hybrid Área de Conservación Guanacaste (ACG). This semi-decentralized conservation entity has today a staff of ~150 paraprofessional resident Costa Ricans, biodeveloping at least 650,000 multicellular species (Eucaryotes) into perpetuity for ACG survival through being integrated with its local, regional, national, and international society. ACG began in 1985 as an ongoing exercise of landscape-level ecosystem rescue and restoration of a continuous swath from 6 km out in the Pacific ocean, across dry forested lowlands, up and over the volcanic Cordillera Guanacaste, and down into the rain-forested Caribbean lowlands. It is being impacted by climate change, yet its diverse ecosystems hold hope for major biodiversity survival, albeit in new community assemblages. It quickly became simultaneously a biophysical challenge and an administratively novel challenge in decentralized conservation in a democratic tropical country. ACG specializes at being managed by on-the-job stimulated and trained residents with minimal formal education, searching for ways to involve ACG in its society without damaging its wildness, and pioneering ways to render wild biodiversity to being a welcome member at society's negotiating table. It continues to pay its bills through government subsidy, generous donors, payments for services, project grants, and huge in-kind contributions from mutualisms. ACG hopes that the concept will spread south–south to other tropical countries while they still have some of their wild biodiversity with which to integrate.     

Epinephrine,DNA integrity and oxidative stress in workers exposed to extremely low-frequency electromagnetic fields (ELF-EMFs) at 132 kV substations

Abstract

There is apprehension about widespread use of electrical and electromagnetic gadgets which are supposed to emit electromagnetic radiations. Reports are controversy. These electromagnetic fields (EMFs) have considerable effect on endocrine system of exposed subjects. This study was focused to assess the possible bioeffects of extremely low-frequency (ELF)-EMFs on epinephrine level, DNA damage and oxidative stress in subjects occupationally exposed to 132?kV high-voltage substations. The blood sample of 142 exposed subjects and 151 non-exposed individuals was analyzed. Plasma epinephrine was measured by enzyme-linked immunosorbent assay, DNA damage was studied by alkaline comet assay along with oxidative stress. Epinephrine levels of sub-groups showed mean concentration of 75.22 ± 1.46, 64.43 ± 8.26 and 48.47 ± 4.97 for high, medium and low exposed groups, respectively. DNA damage ranged between 1.69?µm and 9.91?µm. The oxidative stress levels showed significant increase. The individuals employed in the live-line procedures were found to be vulnerable for EM stress with altered epinephrine concentrations, DNA damage and increased oxidative stress.     

Spider diversity across an elevation gradient in Área de Conservación Guanacaste (ACG), Costa Rica

Throughout the Neotropics, temperature and precipitation change with elevation and these changes affect the assemblage of species at any particular elevation. We documented the diversity of litter-inhabiting spiders, (Arachnida: Araneae) along a Costa Rican elevational gradient as it relates to covarying abiotic factors such as temperature and precipitation. The spiders we collected were principally unidentifiable juveniles, and so we used Barcode Index Numbers (BINs) derived from DNA barcodes as proxies for species-level interim names. We contrasted these taxon-based estimates with phylogenetic measures of alpha- and beta-diversity derived from both the mitochondrial DNA barcode region and a multi-gene phylogeny of spiders and found that neither the abundance nor the species richness of spiders was significantly correlated with elevation, temperature, or precipitation. However, we did find that spider assemblages in the upper elevation cloud forests were phylogenetically clustered, (and this pattern was unrelated to whether the phylogenetic patterns were derived mitochondrially or from a multi-gene analysis). One standard explanation for such a pattern is that harsh abiotic conditions in higher elevation forests have selected for particular spider lineages; however, this remains to be tested fully. The diversity of leaf-litter spider species we uncovered was high and further sampling of spider abundance and diversity across the ACG is likely to yield many new species.     

Are endogenous sex hormones related to DNA damage in paradoxically sleep-deprived female rats?

The aim of this investigation was to evaluate overall DNA damage induced by experimental paradoxical sleep deprivation (PSD) in estrous-cycling and ovariectomized female rats to examine possible hormonal involvement during DNA damage. Intact rats in different phases of the estrous cycle (proestrus, estrus, and diestrus) or ovariectomized female Wistar rats were subjected to PSD by the single platform technique for 96 h or were maintained for the equivalent period as controls in home-cages. After this period, peripheral blood and tissues (brain, liver, and heart) were collected to evaluate genetic damage using the single cell gel (comet) assay. The results showed that PSD caused extensive genotoxic effects in brain cells, as evident by increased DNA migration rates in rats exposed to PSD for 96 h when compared to negative control. This was observed for all phases of the estrous cycle indistinctly. In ovariectomized rats, PSD also led to DNA damage in brain cells. No significant statistically differences were detected in peripheral blood, the liver or heart for all groups analyzed. In conclusion, our data are consistent with the notion that genetic damage in the form of DNA breakage in brain cells induced by sleep deprivation overrides the effects related to endogenous female sex hormones.     

Ultrastructural description of Euglena pailasensis (Euglenozoa) from Rincón de la Vieja volcano, Guanacaste, Costa Rica

The euglenoids are unicellular eukaryotic flagellates living in a diversity of soils and aquatic environments and ecosystems. This study describes the ultrastructure of an euglenoid isolated from the surface of a boiling mud pool with temperatures ranging from 38 to 98 degrees C and pH 2 - 4. The hot mud pool is located in Area de Pailas de Barro, Las Pailas, Rincón de la Vieja Volcano, Guanacaste, Costa Rica. The morphological characterization of the Euglena pailasensis was performed by SEM and TEM. It was determined that, although the euglenoid was obtained from an extreme volcanic environment, the general morphology corresponds to that of a typical member of Euglena of 30-45 microm long and 8-10 microm wide, with membrane, pellicle, chloroplasts, mitochondria, nucleus, pigments and other cytoplasmic organelles. E. pailasensis is delimited by a membrane and by 40 to 90 pellicle strips. It was observed up to 5 elongated chloroplasts per cell. The chloroplast contains several osmiophilic globules and a pyrenoid penetrated by few thylakoid pairs. The nutritious material is reserved in numerous small paramylon grains located at the center of the cell, mitocondria are characterized by the presence of crests in radial disposition toward the interior of the lumen. It was also observed around the external surface "pili" like filaments originating from the pellicle strips. There is no evidence for the presence of flagella in the ampulla (reservoir/canal area), a fact confirmed by negative staining, and a difference regarding other species of Euglena. The observed ultrastructural characteristics are not sufficient to explain the adaptation of this species to acid and hot environments.     

Primate life history,social dynamics,ecology, and conservation: Contributions from long-term research in Área de Conservación Guanacaste,Costa Rica

Research on non-human primates in the endangered tropical dry forest of Sector Santa Rosa (SSR), Área de Conservación Guanacaste (ACG), was launched in 1983 and is now one of the longest running studies of primates globally. Such continuous study provides a rare opportunity to ask questions that are only answerable through decades-long monitoring of these long-lived monkeys. In turn, the mounting data generated by long-term study, including knowledge of lifetime reproductive success, familial relatedness, comprehensive behavioral and dietary repertoires, and patterns of inter- and intra-annual variation in forest productivity, provide diverse opportunities to researchers, and facilitate studies that are of shorter duration. Here, we review some of the contributions of our longitudinal research on white-faced capuchins and Geoffroy's spider monkeys, together with newer studies on mantled howler monkeys. We begin by synthesizing findings from our research on demography, dispersal, social relationships, and reproduction. These life history and social traits interact with their foraging and sensory ecology, which we review next. We end by highlighting how the longitudinal study of primates in Sector Santa Rosa has made direct and indirect contributions to the conservation of the critically endangered dry forest biome and its inhabitants, as well as to education, community, and forest restoration initiatives. In particular, we focus our review on how long-term research is uniquely positioned to make key contributions spanning different topical areas.     

A survey of homopteran species (Auchenorrhyncha) from coffee shrubs and poró and laurel trees in shaded coffee plantations,in Turrialba,Costa Rica

A survey of homopteran species (Auchenorryncha) was conducted in coffee plantations with no shade (C), and in those with shade of either poró (Erythrina poeppigiana) (CP) or poró plus laurel (Cordia alliodora) (CPL), in Turrialba, Costa Rica. A total of 130 species in ten families were collected, dominated by Cicadellidae (82 species). Species richness was highest in the CP system (88), followed by CPL (74) and C systems (60). Five most common species for all systems were Fusigonalia lativittata, Hebralebra nicaraguensis, Neocoelidia sp., Oliarus sp. and Clastoptera sp. Diversification of the coffee agroecosystem favors some species while limiting others, and have no effect on the majority of species. Thus, only F. lativittata, Neocoelidia sp. and Scaphytopius ca. latidens were well represented in all systems, but were more abundant in coffee shrubs. Additionally, the following were the dominant species in each system: Graphocephala sp. 1 (C), F. lativittata (CP) and H. nicaraguensis (CPL). Four species abundant on laurel trees, including H. nicaraguensis, appeared almost exclusively on these tree species. Species similarity was highest on the CP and CPL systems (51% of the species in common), followed by the C and CP (39%) and the C and CPL systems (38%). These findings show that even disturbed systems can harbor many insect species, so that they deserve attention from conservation advocates and biologists.     

Activation of DNA damage response pathways in human mesenchymal stem cells exposed to cisplatin or γ-irradiation

DNA damaging agents are widely used in treatment of hematogical malignancies and solid tumors. While effects on hematopoietic stem cells have been characterized, less is known about the DNA damage response in human mesenchymal stem cells (hMSCs) in the bone marrow stroma, progenitors of osteoblasts, chondrocytes and adipocytes. To elucidate the response of undifferentiated hMSCs to γ-irradiation and cisplatin, key DNA damage responses have been characterised in hMSCs from normal adult donors. Cisplatin and γ-irradiation activated the DNA damage response in hMSCs, including induction of p53 and p21, and activation of PI3 kinase-related protein kinase (PIKK)-dependent phosphorylation of histone H2AX on serine 139, and replication protein A2 on serine4/serine8. Chemical inhibition of ATM or DNA-PK reduced DNA damage-induced phosphorylation of H2AX, indicating a role for both PIKKs in the response of hMSCs to DNA damage. Consistent with repair of DNA strand breaks, γ-H2AX staining decreased by 24 hours following gamma-irradiation. γ-irradiation arrested hMSCs in the G₁ phase of the cell cycle, while cisplatin induced S-phase arrest, mediated in part by the ATR/Chk1 checkpoint pathway. In hMSCs isolated from a chronic lymphocytic leukemia (CLL) patient, p53 and p21 were induced by cisplatin and γ-irradiation, while RPA2 was phosphorylated on serine4/8 in particular following cisplatin. Compared to peripheral blood lymphocytes or the leukemia cell line K562, both normal hMSCs and CLL-derived hMSCs were more resistant to cisplatin and γ-irradiation. These results provide insights into key pathways mediating the response of bone marrow-derived hMSCs to DNA damaging agents used in cancer treatment.     

Parapharyngodon duniae n. sp. (Nematoda: Pharyngodonidae) in Phrynohyas venulosa (Anura: Hylidae) from the Area de Conservación Guanacaste, Guanacaste, Costa Rica

Parapharyngodon duniae n. sp. (Nematoda: Pharyngodonidae) in the large intestine of the veined tree frog, Phrynohyas venulosa, from the Area de Conservación Guanacaste in northwestern Costa Rica is described and illustrated. Parapharyngodon duniae n. sp. represents the 34th species assigned to the genus, the 10th species from the Neotropical Realm, and only the third species to parasitize anurans. It is distinguished from the other Neotropical species by having postbulbar ovaries and a prebulbar excretory pore.     

Procyrnea chabaud, 1958 (Nematoda: Habronematoidea: Habronematidae) in birds from the Area de Conservación Guanacaste, Costa Rica, including descriptions of 3 new species

Four species of Procyrnea were collected in birds from the Area de Conservacion Guanacaste, Costa Rica. Procyrnea brevicaudata n. sp. in Crypturellus cinnamomeus resembles P. ficheuri, P. murrayi, P. ameerae, P. dollfusi, and P. aptera in lacking lateral alae but differs from all these species in having 2 longitudinal ridges on the left side of the body, in having a sinistral rather than ventral vulvar opening, and in having dorsally bent rather than straight female tails. Procyrnea mawsonae n. sp., in Buteo magnirostris, is similar to P. strialata in body size and in having 2 transverse striated lateral alae, but differs by having longer and differently shaped spicules, and by lacking a single preanal sessile papilla. Procyrnea mclennanae n. sp., in Heliomaster constantii, is similar to P. strialata (Zhang, 1991) and P. mawsonae n. sp. in having 2 transverse striated lateral alae, but it can be distinguished from P. strialata and P. mawsonae in having 4 rather than 3 small teeth on the interior border of the pseudolabia, in having unequal rather than equal lateral alae, and in having longer spicules. Procyrnea sp., on the basis of a single adult male in Campephilus guatemalensis, resembles P. suraiyae, P. tulostoma, and P. unilateralis in possessing a single and long lateral ala, but can be distinguished from P. suraiyae and P. tulostoma in the length of the left spicule, in the left spicule having a bifid distal end, the right spicule having a rounded distal end rather than both spicules having pointed distal ends, and in having the lateral ala beginning at the lip region instead of posterior to the cervical papillae. It differs from P. uncinipenis in having a spicule ratio of 1:3.5 rather than 1:2.5, in the left spicule having a bifid rather than alate distal end, and in the absence of a single preanal papilla.     

Lytopylus Förster (Hymenoptera, Braconidae, Agathidinae) species from Costa Rica, with an emphasis on specimens reared from caterpillars in Area de Conservación Guanacaste

Twelve species of Costa Rican Lytopylus are treated; these include all species reared from Lepidoptera caterpillars in Area de Conservación Guanacaste, Costa Rica, over 32 years of caterpillar inventory, as well as two species recorded in the literature as occurring in Costa Rica. Ten new species are described, i.e., Lytopylus bradzlotnicki, Lytopylus colleenhitchcockae, Lytopylus gregburtoni, Lytopylus jessicadimauroae, Lytopylus jessiehillae, Lytopylus mingfangi, Lytopylus rebeccashapleyae, Lytopylus robpringlei, Lytopylus sandraberriosae, Lytopylus vaughntani. The following species are transferred to Lytopylus: Metriosoma flavicalcar Enderlein 1920 to Lytopylus flavicalcarcomb. n.; Bassus macadamiae Brice?o and Sharkey 2000 to Lytopylus macadamiaecomb. n.; Metriosoma bicarinatum Enderlein 1920 to Lytopylus bicarinatumcomb. n.; Metriosoma brasiliense Enderlein 1920 to Lytopylus brasiliensecomb. n.; Bassus tayrona Campos 2007 to Lytopylus tayronacomb. n.; Microdus femoratus Cameron 1887 to Lytopylus femoratuscomb. n.; Microdus melanocephalus Cameron 1887 to Lytopylus melanocephaluscomb. n.; Bassus pastranai Blanchard 1952 to Lytopylus pastranaicomb. n.; Agathis nigrobalteata Cameron 1911 to Lytopylus nigrobalteatuscomb. n. Two keys to species of Lytopylus are presented, one interactive and the other static.