Development of Hepatozoon caimani (Carini, 1909) Pess a,De Biasi & De Souza, 1972 in the Caiman Caiman c. crocodilus,the frog Rana catesbeiana and the mosquito Culex fatigans

The sporogony of Hepatozoon caimani has been studied, by light microscopy, in the mosquito Culex fatigans fed on specimens of the caiman Caiman c. crocodilus showing gametocytes in their peripheral blood. Sporonts iniciate development in the space between the epithelium of the insect gut and the elastic membrane covering the haemocoele surface of the stomach. Sporulating oocysts are clustered on the gut, still invested by the gut surface membrane. Fully mature oocysts were first seen 21 days after the blood-meal. No sporogonic stages were found in some unidentified leeches fed on an infected caiman, up to 30 days following the blood-meal. When mosquitoes containing mature oocysts were fed to frogs (Leptodactylus fuscus and Rana catesbeiana), cysts containing cystozoites developed in the internal organs, principally the liver. Feeding these frogs to farm-bred caimans resulted in the appearance of gametocytes in their peripheral blood at some time between 59 and 79 days later, and the development of tissue cysts in the liver, spleen, lungs and kidneys. Transmission of the parasite was also obtained by feeding young caimans with infected mosquitoes and it is suggested that both methods occur in nature. The finding of similar cysts containing cystozoites in the semi-aquatic lizard Neusticurus bicarinatus, experimentally fed with infected C. fatigans, suggests that other secondary hosts may be involved.     

Clinical Profiles and Factors Associated with Death in Adults with Dengue Admitted to Intensive Care Units,Minas Gerais,Brazil

The purpose of our study was to describe the clinical profile of dengue-infected patients admitted to Brazilian intensive care units (ICU) and evaluate factors associated with death. A longitudinal, multicenter case series study was conducted with laboratory-confirmed dengue patients admitted to nine Brazilian ICUs situated in Minas Gerais state, southeastern Brazil from January 1, 2008, to December 31, 2013. Demographic, clinical and laboratory data; disease severity scores; and mortality were evaluated. A total of 97 patients were studied. The in-ICU and in-hospital mortality rates were 18.6% and 19.6%, respectively. Patients classified as having severe dengue according to current World Health Organization classifications showed an increased risk of death in a univariate analysis. Nonsurvivors were older, exhibited lower serum albumin concentrations and higher total leukocyte counts and serum creatinine levels. Other risk factors (vomiting, lethargy/restlessness, dyspnea/respiratory distress) were also associated with death in a univariate analysis. Multivariate analysis indicated that in-hospital mortality was significantly associated with Acute Physiology and Chronic Health Evaluation II and the Sequential Organ Failure Assessment score. The ICU and in-hospital mortality observed in this study were higher than values reported in similar studies. An increased frequency of ICU admission due to severe organ dysfunction, higher severity indices and scarcity of ICU beds may partially explain the higher mortality.     

Small tropical forest trees have a greater capacity to adjust carbon metabolism to long-term drought than large canopy trees

The response of small understory trees to long-term drought is vital in determining the future composition, carbon stocks and dynamics of tropical forests. Long-term drought is, however, also likely to expose understory trees to increased light availability driven by drought-induced mortality. Relatively little is known about the potential for understory trees to adjust their physiology to both decreasing water and increasing light availability. We analysed data on maximum photosynthetic capacity (J_max, V_cmax), leaf respiration (R_leaf), leaf mass per area (LMA), leaf thickness and leaf nitrogen and phosphorus concentrations from 66 small trees across 12 common genera at the world's longest running tropical rainfall exclusion experiment and compared responses to those from 61 surviving canopy trees. Small trees increased J_max, V_cmax, R_leaf and LMA (71, 29, 32, 15% respectively) in response to the drought treatment, but leaf thickness and leaf nutrient concentrations did not change. Small trees were significantly more responsive than large canopy trees to the drought treatment, suggesting greater phenotypic plasticity and resilience to prolonged drought, although differences among taxa were observed. Our results highlight that small tropical trees have greater capacity to respond to ecosystem level changes and have the potential to regenerate resilient forests following future droughts.     

Synthesis and biological evaluation of new active For‐Met‐Leu‐Phe‐OMe analogues containing para‐substituted Phe residues

In the present study, we report synthesis and biological evaluation of the N‐Boc‐protected tripeptides 4a–l and N‐For protected tripeptides 5a–l as new For‐Met‐Leu‐Phe‐OMe (fMLF‐OMe) analogues. All the new ligands are characterized by the C‐terminal Phe residue variously substituted at position 4 of the aromatic ring. The agonism of 5a–l and the antagonism of 4a–l (chemotaxis, superoxide anion production, lysozyme release as well as receptor binding affinity) have been examined on human neutrophils. No synthesized compounds has higher activity than the standard fMLF‐OMe tripeptide to stimulate chemotaxis, although compounds 5a and 5c with ‐CH₃ and ‐C(CH₃)₃, respectively, in position 4 on the aromatic ring, are better than the standard tripeptide to stimulate the production of superoxide anion, in higher concentration. Compounds 4f and 4i , containing ‐F and ‐I in position 4, respectively, on the aromatic ring of phenylalanine, exhibit significant chemotactic antagonism. The influence of the different substitution at the position 4 on the aromatic ring of phenylalanine is discussed. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.     

Forecasting Temporal Dynamics of Cutaneous Leishmaniasis in Northeast Brazil

Introduction

Cutaneous leishmaniasis (CL) is a vector-borne disease of increasing importance in northeastern Brazil. It is known that sandflies, which spread the causative parasites, have weather-dependent population dynamics. Routinely-gathered weather data may be useful for anticipating disease risk and planning interventions.

Methodology/Principal Findings

We fit time series models using meteorological covariates to predict CL cases in a rural region of Bahía, Brazil from 1994 to 2004. We used the models to forecast CL cases for the period 2005 to 2008. Models accounting for meteorological predictors reduced mean squared error in one, two, and three month-ahead forecasts by up to 16% relative to forecasts from a null model accounting only for temporal autocorrelation.

Significance

These outcomes suggest CL risk in northeastern Brazil might be partially dependent on weather. Responses to forecasted CL epidemics may include bolstering clinical capacity and disease surveillance in at-risk areas. Ecological mechanisms by which weather influences CL risk merit future research attention as public health intervention targets.     

Monocyte-Derived Dendritic Cells from Patients with Dermatophytosis Restrict the Growth of Trichophyton rubrum and Induce CD4-T Cell Activation

Dermatophytes are the most common agents of superficial mycoses that are caused by mold fungi. Trichophyton rubrum is the most common pathogen causing dermatophytosis. The immunology of dermatophytosis is currently poorly understood. Recently, our group investigated the interaction of T. rubrum conidia with peritoneal mouse macrophages. We found that macrophages phagocytose T. rubrum conidia resulted in a down-modulation of class II major histocompatibility complex (MHC) antigens and in the expression of co-stimulatory molecules. Furthermore, it induced the production of IL-10, and T. rubrum conidia differentiated into hyphae that grew and killed the macrophages after 8 hrs of culture. This work demonstrated that dendritic cells (DCs) and macrophages, from patients or normal individuals, avidly interact with pathogenic fungus T. rubrum. The dermatophyte has two major receptors on human monocyte-derived DC: DC-SIGN and mannose receptor. In contrast macrophage has only mannose receptor that participates in the phagocytosis or bound process. Another striking aspect of this study is that unlike macrophages that permit rapid growth of T. rubrum, human DC inhibited the growth and induces Th activation. The ability of DC from patients to interact and kill T. rubrum and to present Ags to T cells suggests that DC may play an important role in the host response to T. rubrum infection by coordinating the development of cellular immune response.     

Protist Biodiversity and Biogeography in Lakes From Four Brazilian River–Floodplain Systems

The biodiversity and biogeography of protists inhabiting many ecosystems have been intensely studied using different sequencing approaches, but tropical ecosystems are relatively under‐studied. Here, we sampled planktonic waters from 32 lakes associated with four different river–floodplains systems in Brazil, and sequenced the DNA using a metabarcoding approach with general eukaryotic primers. The lakes were dominated by the largely free‐living Discoba (mostly the Euglenida), Ciliophora, and Ochrophyta. There was low community similarity between lakes even within the same river–floodplain. The protists inhabiting these floodplain systems comprise part of the large and relatively undiscovered diversity in the tropics.