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BackgroundThe presence of animal reservoirs in Schistosoma japonicum infection has been a major obstacle in the control of schistosomiasis. Previous studies have proven that the inclusion of control measures on animal reservoir hosts for schistosomiasis contributed to the decrease of human cases. Animal surveillance should therefore be included to strengthen and improve the capabilities of current serological tests.Methodology/Principal FindingsThioredoxin peroxidase-1 (SjTPx-1) and four tandem repeat proteins (Sj1TR, Sj2TR, Sj4TR, Sj7TR) were initially evaluated against human sera. The previous test showed high sensitivity and specificity for antibody detection against SjTPx-1 and Sj7TR. In this study, the immunodiagnostic potential of these recombinant proteins was evaluated using enzyme-linked immunoassay on 50 water buffalo serum samples collected in Cagayan, the Philippines as compared with the soluble egg antigen (SEA). For specificity, 3 goat serum samples positive with Fasciola hepatica were used and among the antigens used, only SEA showed cross-reaction. Stool PCR targeting the S. japonicum 82 bp mitochondrial NAD 1 gene was done to confirm the true positives and served as the standard test. Twenty three samples were positive for stool PCR. SjTPx-1 and Sj1TR gave the highest sensitivity among the recombinant proteins tested for water buffalo samples with 82.61% and 78.26% respectively which were higher than that of SEA (69.57%).Conclusions/SignificanceThese results prove that SjTPx-1 works both for humans and water buffaloes making it a good candidate antigen for zoonotic diagnosis. Sj1TR showed good results for water buffaloes and therefore can also be used as a possible candidate for detecting animal schistosome infection.

Estimation of turbulence intensity with a fast-response thermistor is examined by comparing the energy dissipation rate from a Fastip Probe, model 07 (FP07), thermistor with from a shear probe, both of which are attached to a free-fall microstructure profiler with the fall rate of 0.6–0.7 m s−1. Temperature gradient spectra corrected with previously introduced frequency response functions represented by a single-pole low-pass filter yields with a bias that strongly depends on turbulence intensity. Meanwhile, the correction with the form of a double-pole low-pass filter derives less bias than of single-pole low-pass filter. The rate is compatible with when the double-pole correction with the time constant of 3 × 10−3 s is applied, and 68% of data are within a factor of 2.8 of in the wide range of = 10−10–3 × 10−7 W kg−1. The rate is still compatible with even in the anisotropy range, where the buoyancy Reynolds number is 20–100. Turbulence estimation from the fast-response thermistor is thus confirmed to be valid in this range by applying the appropriate correction to temperature gradient spectra. Measurements with fast-response thermistors, which have not been common because of their poor frequency response, are less sensitive to the vibration of profilers than those with shear probes. Hence, measurements could be available when a fast-response thermistor is attached to a CTD frame or a float, which extends the possibility of obtaining much more turbulence data in deep and wide oceans.

Anemia is a typical symptom during visceral leishmaniasis (VL). We performed a systematic analysis of the literature on anemia in VL to understand the prevalence, severity, and possible mechanisms. Anemia is very common in VL patients with an overall prevalence higher than 90 %. The degree of anemia in VL is moderate to severe (hemoglobin level ∼7.5 g/dl), and the status can be recovered by treatment with antileishmanial drugs within a certain period of time. Possible pathogeneses of anemia in VL based on clinical observations included anti-RBC antibodies, dysfunction in erythropoiesis, and hemophagocytosis in the bone marrow or spleen, while hemolysis is a more likely cause than dyserythropoiesis. In hamsters with experimental VL, hemophagocytosis induced by immune complex and changes on erythrocyte membrane is speculated as the pathogenesis for anemia. In contrast, our recent study on murine VL indicated that hemophagocytosis contributes to anemia in contrast to lower contribution of anti-RBC antibodies or dysfunction in erythropoiesis. Together, hemophagocytosis is most likely associated with anemia in VL, and elucidation of the immunological mechanisms may lead to development of novel interventions to manage the symptom.

Leishmania amazonensis recombinants expressing the enhanced green fluorescent protein (egfp) gene or β-galactosidase gene (lacZ) were constructed for drug screening and histopathological analysis. The egfp or lacZ in a leishmanial transfection vector, p6.5, was introduced into L. amazonensis promastigotes, and egfp or lacZ-carrying recombinant L. amazonensis, La/egfp and La/lacZ, respectively, were obtained. Expression of egfp or lacZ in both promastigotes and amastigotes could be clearly visualized by fluorescence microscopy or by light microscopy with 5-bromo-4-chloro-3-indolyl-β-Dgalactopyranoside (X-Gal), respectively. Fluorescence signal and β-galactosidase activity measured by a colorimetric reaction with chlorophenol red β-D-galactopyranoside (CPRG) were well correlated to the numbers of these parasites. The inhibitory concentration (IC 50 ) of a leishmanicidal drug, amphotericin B, in L. amazonensis promastigotes measured using La/egfp and La/lacZ was similar to that measured by conventional methods such as cell counting, thymidine incorporation and colorimetric assay. Furthermore, the fluorescence signal and absorbance of CPRG correlated well with the numbers of La/egfp and La/lacZ amastigotes in macrophages, respectively, suggesting La/egfp and La/lacZ can be a convenient and useful tool for drug screening not only in promastigotes, but also in amastigotes of L. amazonensis. La/lacZ collected from mouse tissues four weeks after the parasite infection were stained well with X-Gal. La/lacZ allowed parasite detection at high sensitivity in the tissues of infected mice and will be useful for following infections in macrophages in vivo. Thus, the marker-transfected Leishmania parasites constructed in this study will be useful for analyses of Leishmania parasites, especially at the intracellular stage.

A new xenicane diterpenoid, cristaxenicin A (1), has been isolated from the deep sea gorgonian Acanthoprimnoa cristata. The structure of 1 was elucidated on the basis of spectral analysis including NMR and MS. The absolute configuration of 1 was determined on the basis of quantum chemical calculation of CD spectra. Cristaxenicin A (1) showed antiprotozoal activities against Leishmania amazonensis and Trypanosoma congolense with IC(50) values of 0.088 and 0.25 μM, respectively.

Hemophagocytosis is a phenomenon in which macrophages phagocytose blood cells. There are reports on up-regulated hemophagocytosis in patients with infectious diseases including typhoid fever, tuberculosis, influenza and visceral leishmaniasis (VL). However, mechanisms of infection-associated hemophagocytosis remained elusive due to a lack of appropriate animal models. Here, we have established a mouse model of VL with hemophagocytosis. At 24 weeks after infection with 1 x 107 Leishmania donovani promastigotes, BALB/cA mice exhibited splenomegaly with an average tissue weight per body weight of 2.96%. In the tissues, 28.6% of macrophages contained phagocytosed erythrocytes. All of the hemophagocytosing macrophages were parasitized by L. donovani, and higher levels of hemophagocytosis was observed in heavily infected cells. Furthermore, more than half of these hemophagocytes had two or more macrophage-derived nuclei, whereas only 15.0% of splenic macrophages were bi- or multi-nuclear. These results suggest that direct infection by L. donovani causes hyper-activation of host macrophages to engulf blood cells. To our knowledge, this is the first report on hemophagocytosis in experimental Leishmania infections and may be useful for further understanding of the pathogenesis.

Turbulence intensity estimated from fast-response thermistors is compared between conductivitytemperature-depth (CTD)-attached and free-fall microstructure profilers, conducted at the same location within 2 h. The agreement is generally good but anomalously overestimated values, deviating from a lognormal distribution, appear sporadically in the CTD-attached method. These overestimated outliers are evident as spiky patches in the raw temperature gradient profiles.