Searching for Euglossa cyanochlora Moure, 1996 (Hymenoptera: Apidae), one of the rarest bees in the world

Euglossa cyanochlora Moure, 1996 (Hymenoptera: Apidae: Euglossina) is known from only two specimens and is considered as one of the rarest bees. An intensive search for this species in its expected area of occurrence in eastern Brazil was carried out during three consecutive summers and involved over 1,000?h of active sampling in 50 sites distributed among 20 forest remnants. Almost 15,000 orchid bee males were attracted to scent baits and collected, but only 24 of them belonged to E. cyanochlora. Some degree of mitochondrial gene (COI, cytB, and 16S) variation was observed in this species. Although no intra-specific variation was identified at the 16S locus, three and six haplotypes were characterized at the COI and cytB genes, respectively. Combined data from field work and molecular analysis suggest that the species southernmost distribution limit is close to its type locality, near Parque Nacional do Monte Pascoal, in southern Bahia. The conservation status of E. cyanochlora is discussed and measures for its protection are here proposed.     

Cytokine Profiles at Admission Can Be Related to Outcome in AIDS Patients with Cryptococcal Meningitis

Cryptococcal meningitis (CM) remains as common life-threatening AIDS-defining illness mainly in resource-limited settings. Previous reports suggested that baseline cytokine profiles can be associated to fungal burden and clinical outcome. This study aimed to evaluate the baseline cytokine profiles in AIDS patients with CM and its relation with the outcome at weeks 2 and 10. Thirty AIDS patients with CM diagnosed by cerebrospinal fluid (CSF) Cryptococcus neoformans positive culture, India ink stain and cryptococcal antigen test were prospectively evaluated. As controls, 56 HIV-infected patients without CM and 48 non-HIV individuals were included. Baseline CSF and sera levels of IL-2, IL-4, IL-8, IL-10, IL-12p40, IL-17A, INF-γ and TNF-α were measured by ELISA. Of 30 CM patients, 24 (80%) were male, median age of 38.1. The baseline CSF high fungal burden and positive blood culture were associated with a positive CSF culture at week 2 (p = 0.043 and 0.029). Most CSF and sera cytokines presented higher levels in CM patients than control subjects (p < 0.05). CSF levels of IL-8, IL-12p40, IL-17A, TNF-α, INF-γ and sera TNF-α were significantly higher among survivors at weeks 2 and 10 (p < 0.05). Patients with increased intracranial pression exhibited CSF IL-10 high levels and poor outcome at week 10 (p = 0.032). Otherwise, baseline CSF log10 IFN-γ and IL-17A were negatively correlated with fungal burden (r = -0.47 and -0.50; p = 0.0175 and 0.0094, respectively). The mortality rate was 33% (10/30) at week 2 and 57% (17/30) at week 10. The severity of CM and the advanced immunodeficiency at admission were related to a poor outcome in these patients. Otherwise, the predominant Th1 cytokines profile among survivors confirms its pivotal role to infection control and would be a prognostic marker in cryptococcal meningitis.     

Asymmetric dispersal and colonization success of Amazonian plant-ants queens

Background

The dispersal ability of queens is central to understanding ant life-history evolution, and plays a fundamental role in ant population and community dynamics, the maintenance of genetic diversity, and the spread of invasive ants. In tropical ecosystems, species from over 40 genera of ants establish colonies in the stems, hollow thorns, or leaf pouches of specialized plants. However, little is known about the relative dispersal ability of queens competing for access to the same host plants.

Methodology/Principal Findings

We used empirical data and inverse modeling—a technique developed by plant ecologists to model seed dispersal—to quantify and compare the dispersal kernels of queens from three Amazonian ant species that compete for access to host-plants. We found that the modal colonization distance of queens varied 8-fold, with the generalist ant species (Crematogaster laevis) having a greater modal distance than two specialists (Pheidole minutula, Azteca sp.) that use the same host-plants. However, our results also suggest that queens of Azteca sp. have maximal distances that are four-sixteen times greater than those of its competitors.

Conclusions/Significance

We found large differences between ant species in both the modal and maximal distance ant queens disperse to find vacant seedlings used to found new colonies. These differences could result from interspecific differences in queen body size, and hence wing musculature, or because queens differ in their ability to identify potential host plants while in flight. Our results provide support for one of the necessary conditions underlying several of the hypothesized mechanisms promoting coexistence in tropical plant-ants. They also suggest that for some ant species limited dispersal capability could pose a significant barrier to the rescue of populations in isolated forest fragments. Finally, we demonstrate that inverse models parameterized with field data are an excellent means of quantifying the dispersal of ant queens.     

Effects of the Nile tilapia (Oreochromis niloticus L.) on the plankton community of a tropical reservoir during and after an algal bloom

Hydrobiologia - The invasive species Nile tilapia is a filter-feeding omnivorous fish that can have a negative effect on zooplankton and phytoplankton resources. However, the strength of its...     

Nimesulide inhibits pathogenic fungi: PGE2-dependent mechanisms

Certain non-steroidal anti-inflammatory drugs can inhibit fungal growth, fungal prostaglandin E2 production, and enzyme activation. This study aims to investigate the antifungal effect of nimesulide against pathogenic filamentous fungi and yeast. The experiments detailed below were also designed to investigate whether the action is dependent on E2 fungal prostaglandins. Our data showed that nimesulide exhibited potent antifungal activity, mainly against Trichophyton mentagrophytes (ATCC 9533) and Cryptococcus neoformans with MIC values of 2 and 62 μg/mL, respectively. This drug was also able to inhibit the growth of clinic isolates of filamentous fungi, such as Aspergillus fumigatus, and dermatophytes, such as T. rubrum, T. mentagrophytes, Epidermophyton floccosum, Microsporum canis, and M. gypseum, with MIC values ranging from 112 to 770 μg/mL. Our data also showed that the inhibition of fungal growth by nimesulide was mediated by a mechanism dependent on PGE2, which led to the inhibition of essential fungal enzymes. Thus, we concluded that nimesulide exerts a fungicidal effect against pathogenic filamentous fungi and yeast, involving the inhibition of fungal prostaglandins and fungal enzymes important to the fungal growth and colonization.     

The Potential Role of Scattered Trees for Ant Conservation in an Agriculturally Dominated Neotropical Landscape

Although biological conservation has traditionally focused on the protection of pristine areas, it is becoming increasingly evident that efforts should also be made toward the maintenance of biological diversity in human‐managed ecosystems. We evaluated the potential role of scattered, remnant trees in enhancing ant diversity in agricultural lands within a biodiversity hotspot, namely the Cerrado savannas of central Brazil. Ant collections were performed in, beneath, and away from the crowns of a native tree species growing in planted pastures, soy fields, and in small (<400 ha) savanna reserves. Significantly more ant species were found beneath than 30 m away from scattered trees. The magnitude of this effect was similar in soy fields and in pastures at all scales of our analyses, except at the landscape scale where the effect was comparatively greater in soy fields. Most of the species that occurred more frequently beneath than away from trees nest on ground, indicating that the conservation value of scattered trees goes beyond the mere protection of arboreal ant species. Soy plantations presented a particular species‐poor ground‐dwelling fauna when compared with savannas, whereas differences in the number and composition of arboreal species were less marked. In contrast, the diversity of arboreal‐ and ground‐dwelling ants recorded in and beneath pasture trees was nearly as high as the one found in savannas. It is suggested that pasture trees can have an important value for ant conservation off reserves, particularly in regions where most of the native vegetation has already been cleared.     

Conservation implications of genetic structure in the narrowest endemic quillwort from the Eastern Amazon

The quillwort Isoëtes cangae is a critically endangered species occurring in a single lake in Serra dos Carajás, Eastern Amazon. Low genetic diversity and small effective population sizes (N _e) are expected for narrow endemic species (NES). Conservation biology studies centered in a single species show some limitations, but they are still useful considering the limited time and resources available for protection of species at risk of extinction. Here, we evaluated the genetic diversity, population structure, N _e, and minimum viable population (MVP) of I. cangae to provide information for effective conservation programs. Our analyses were based on 55 individuals collected from the Amendoim Lake and 35,638 neutral SNPs. Our results indicated a single panmictic population, moderate levels of genetic diversity, and N _e in the order of thousands, contrasting the expected for NES. Negative F_IS values were also found, suggesting that I. cangae is not under risk of inbreeding depression. Our findings imply that I. cangae contains enough genetic diversity to ensure evolutionary potential and that all individuals should be treated as one demographic unit. These results provide essential information to optimize ex situ conservation efforts and genetic diversity monitoring, which are currently applied to guide I. cangae conservation plans.     

Metabolism of a subtropical Brazilian lagoon

Total community, planktonic and benthic metabolisms were measured by using the carbon dioxide production and consumption, the diurnal curve' method and the in situ bottle incubation technique over an annual cycle in two sublagoons of the Saquarema Lagoon, Brazil. Metabolic rates of the phytoplankton-based lagoon were characterized by considerable daytime and daily variability in production and respiration, by a seasonal shift between net autotrophy and heterotrophy and by an annual balance of production (P = 105 ± 65 mmoles/m²/dayn = 25) and respiration (R = 102 ± 50 mmoles/m²/dayn = 25). Total community metabolism was similar throughout the lagoon, but phytoplankton assimilation rates and benthic respiration showed spatial differences. Bottle incubations compared to total community free water respiration suggested that the pelagic community was 2–5 times more active than the benthos