Impact of the immune profiles of hypertensive patients with and without obesity on COVID-19 severity.

BACKGROUND: Comorbidities such as obesity, hypertension, and diabetes are associated with COVID-19 development and severity, probably due to immune dysregulation; however, the mechanisms underlying these associations are not clear. The immune signatures of hypertensive patients with obesity with COVID-19 may provide new insight into the mechanisms of immune dysregulation and progression to severe disease in these patients. METHODS: Hypertensive patients were selected prospectively from a multicenter registry of adults hospitalized with COVID-19 and stratified according to obesity (BMI ≥ 30 kg/m²). Clinical data including baseline characteristics, complications, treatment, and 46 immune markers were compared between groups. Logistic regression was performed to identify variables associated with the risk of COVID-19 progression in each group. RESULTS: The sample comprised 213 patients (89 with and 124 without obesity). The clinical profiles of patients with and without obesity differed, suggesting potential interactions with COVID-19 severity. Relative to patients without obesity, patients with obesity were younger and fewer had cardiac disease and myocardial injury. Patients with obesity had higher EGF, GCSF, GMCSF, interleukin (IL)-1ra, IL-5, IL-7, IL-8, IL-15, IL-1ß, MCP 1, and VEGF levels, total lymphocyte counts, and CD8+ CD38+ mean fluorescence intensity (MFI), and lower NK-NKG2A MFI and percentage of CD8+ CD38+ T cells. Significant correlations between cytokine and immune cell expression were observed in both groups. Five variables best predicted progression to severe COVID-19 in patients with obesity: diabetes, the EGF, IL-10, and IL-13 levels, and the percentage of CD8+ HLA-DR+ CD38+ cells. Three variables were predictive for patients without obesity: myocardial injury and the percentages of B lymphocytes and HLA-DR+ CD38+ cells. CONCLUSION: Our findings suggest that clinical and immune variables and obesity interact synergistically to increase the COVID-19 progression risk. The immune signatures of hypertensive patients with and without obesity severe COVID-19 highlight differences in immune dysregulation mechanisms, with potential therapeutic applications.

New Insights on the Mechanisms of Myocardial Injury in Hypertensive Patients With COVID-19.

PURPOSE: Myocardial injury is common in hypertensive patients with 2019 coronavirus disease (COVID-19). Immune dysregulation could be associated to cardiac injury in these patients, but the underlying mechanism has not been fully elucidated. METHODS: All patients were selected prospectively from a multicenter registry of adults hospitalized with confirmed COVID-19. Cases had hypertension and myocardial injury, defined by troponin levels above the 99th percentile upper reference limit, and controls were hypertensive patients with no myocardial injury. Biomarkers and immune cell subsets were quantified and compared between the two groups. A multiple logistic regression model was used to analyze the associations of clinical and immune variables with myocardial injury. RESULTS: The sample comprised 193 patients divided into two groups: 47 cases and 146 controls. Relative to controls, cases had lower total lymphocyte count, percentage of T lymphocytes, CD8+CD38+ mean fluorescence intensity (MFI), and percentage of CD8+ human leukocyte antigen DR isotope (HLA-DR)+ CD38-cells and higher percentage of natural killer lymphocytes, natural killer group 2A (NKG2A)+ MFI, percentage of CD8+CD38+cells, CD8+HLA-DR+MFI, CD8+NKG2A+MFI, and percentage of CD8+HLA-DR-CD38+cells. On multivariate regression, the CD8+HLA-DR+MFI, CD8+CD38+MFI, and total lymphocyte count were associated significantly with myocardial injury. CONCLUSION: Our findings suggest that lymphopenia, CD8+CD38+MFI, and CD8+HLA-DR+MFI are immune biomarkers of myocardial injury in hypertensive patients with COVID-19. The immune signature described here may aid in understanding the mechanisms underlying myocardial injury in these patients. The study data might open a new window for improvement in the treatment of hypertensive patients with COVID-19 and myocardial injury.

NKG2A Expression among CD8 Cells Is Associated with COVID-19 Progression in Hypertensive Patients: Insights from the BRACE CORONA Randomized Trial.

Cardiovascular comorbidities and immune-response dysregulation are associated with COVID-19 severity. We aimed to explore the key immune cell profile and understand its association with disease progression in 156 patients with hypertension that were hospitalized due to COVID-19. The primary outcome was progression to severe disease. The probability of progression to severe disease was estimated using a logistic regression model that included clinical variables and immune cell subsets associated with the primary outcome. Obesity; diabetes; oxygen saturation; lung involvement on computed tomography (CT) examination; the C-reactive protein concentration; total lymphocyte count; proportions of CD4+ and CD8+ T cells; CD4/CD8 ratio; CD8+ HLA-DR MFI; and CD8+ NKG2A MFI on admission were all associated with progression to severe COVID-19. This study demonstrated that increased CD8+ NKG2A MFI at hospital admission, in combination with some clinical variables, is associated with a high risk of COVID-19 progression in hypertensive patients. These findings reinforce the hypothesis of the functional exhaustion of T cells with the increased expression of NKG2A in patients with severe COVID-19, elucidating how severe acute respiratory syndrome coronavirus 2 infection may break down the innate antiviral immune response at an early stage of the disease, with future potential therapeutic implications.

Effects of forage inclusion and cattle breed on apparent digestibility and ruminal pH of steers fed a whole shelled corn-based diet.

Objectives were to evaluate the effects of cattle breed, Holstein or Angus, and forage inclusion on total tract digestibility and ruminal pH in cattle fed a whole shelled corn-based diet. Six Holstein and six Angus steers were assigned to a 2 × 3 factorial arrangement of treatments. Factors included breed, Holstein or Angus, and forage inclusion at 0%, 8%, or 16% forage (dry matter [DM] basis). Steers were fed in a replicated 3 × 3 Latin square, split-plot design. Each period consisted of 14 d diet adaptation followed by 7 d of sample collection. Data were analyzed using the MIXED procedures in SAS (v9.4 SAS Inst. Inc., Cary, NC). Repeated measures were used to analyze changes in ruminal pH over time. There was no interaction of breed × diet (P ≥ 0.19) on dry matter intake (DMI) or digestibility; however, Holstein steers had greater (P = 0.03) DMI than Angus steers. Despite the impact of breed on intake, there was no effect (P ≥ 0.33) of breed on diet digestibility. Digestibility of DM increased (linear; P < 0.01) as forage was removed from the diet, but there were no differences (P ≥ 0.32) in Neutral Detergent Fiber (NDF) and starch digestibility. However, due to the change in diet, NDF intake digested on a grams per day basis increased (P ≤ 0.01) and starch intake digested (g/d) decreased (P = 0.01) as forage inclusion increased. There was a tendency for breed × diet interaction (P = 0.08) on ruminal pH. Holstein steers fed 8% or 16% forage had greater ruminal pH than Holstein steers fed 0% forage; but, ruminal pH of Angus steers was not altered by diet.

In vitro and in situ techniques yield different estimates of ruminal disappearance of barley.

Objectives were to compare in vitro and in situ disappearance of dry matter (DM), neutral detergent fiber (NDF), and starch of traditional (unprocessed and rolled) and hulless (unprocessed) barley. Experiment 1: three barley sources were compared using in vitro techniques. The sources were: 1) traditional barley that was not processed, 2) traditional barley processed through a roller mill, and 3) hulless barley that was not processed. For in vitro incubation, each barley source was ground through a 1-mm screen. Ground barley sources were weighed into bags (25 micron porosity) and incubated in ruminal fluid from two steers fed 80% rolled corn for 3, 6, 12, 24, 48, or 72 h. Intact bags were assayed for NDF; remaining bags were opened and the residual was removed and analyzed to determine disappearance of DM and starch. Experiment 2: the barley sources used in Exp. 1 were compared using in situ techniques. For in situ analysis, each barley source was ground in a Wiley mill with no screen to mimic mastication. Artificially masticated samples were weighed into Dacron bags (50 ± 10 micron porosity) and incubated in eight ruminally fistulated steers (n = 8) for 3, 6, 12, 24, 48, and 72 h. Residual contents were analyzed to determine in situ disappearance of DM, NDF, and starch. Data were analyzed using the MIXED procedures of SAS (9.4 SAS Institute, Cary, NC) with repeated measures. DM disappearance was greatest (P < 0.05) for hulless barley in vitro and for rolled barley in situ, regardless of time postincubation. For both trials, NDF disappearance was greatest (P < 0.05) for hulless barley, regardless of time postincubation. Starch disappearance at all time points was greatest (P < 0.05) for rolled barley in situ. Starch disappearance was greater (P < 0.05) for hulless barley at 6 h of in vitro incubation compared to rolled and unprocessed barley, whereas starch disappearance in vitro was comparable (P = 0.60) between barley sources. When the grains were compared in vitro, minor differences were noted, presumably because barley sources were finely ground prior to incubation. Compared to in vitro estimates, in situ techniques had greater variation in ruminal degradation estimates. Differences observed between in situ and in vitro techniques are driven largely by differences between the procedures. Although laboratory methods are widely used to estimate ruminal degradation, these techniques did not provide comparable estimates of ruminal degradation of barley.

Individual selection of the first backcross generation of passion fruit potentially resistant to the fruit woodiness disease.

The REML/BLUP procedure has been successfully used for genetic progress through individual selection of high-yielding passion fruit genotypes resistant to the Cowpea aphid-borne mosaic virus. This study was thus developed to estimate genetic parameters and predict the gain obtained from individual selection of genotypes in a population derived from backcrosses in passion fruit. The experiment was set up as a randomized block design with four replicates, involving five full-sib families (genotypes from the first backcross). Variance components and the genetic values were estimated for eight agronomic traits via the REML/BLUP procedure. For all traits, genotypic variance between the genotypes from the first backcross showed little contribution to the phenotypic variance. The low heritability estimates obtained for the traits are overcome via individual BLUP estimates. Therefore, it was possible to obtain considerable gains with individual selection for the variables fruit length, average fruit weight, and pulp weight (19.50 to 14.04%; 22.93 to 17.97%; and 10.08 to 7.95%, respectively). For the traits showing lower gains, it is possible to obtain gains indirectly by selecting genotypes for correlated traits. Because this population derives from the first backcross generation, agronomic traits still must be recovered.

Prediction of water intake to Bos indicus beef cattle raised under tropical conditions1.

Water is the most important nutrient in animal nutrition; however, water intake is rarely measured. The objective of this study was to determine whether previously published water intake (WI) equations for beef cattle would accurately predict WI from four experiments conducted under tropical conditions. The experiments were conducted from 2013 to 2015. Nellore (Bos indicus) growing bulls (Exps. 1, 2, and 3) and heifers (Exp. 4) were used in the feedlot trials. In all experiments, animals were fed for ad libitum DMI. The WI, animal performance, diet composition, and environmental data were collected. The prediction of WI using the current published WI equations was evaluated by regressing predicted and measured WI values. The regression was evaluated using the two-hypothesis test: H0: ß0 = 0 and H0: ß1 = 1 and Ha: not H0. If both null hypotheses were not rejected, it was concluded that the tested equation accurately estimated WI. To develop a WI prediction equation based on the input variables, a leave-one-out cross-validation method was proposed. The proposed equation was evaluated using similar methodology described above. All previously published eight equations overestimated WI of cattle used in the four experiments conducted in southeast Brazil. A possible explanation for the overestimate of WI is that previously published WI equations were generated from data collected from predominantly Bos taurus cattle raised under temperate climates. From the data collected from experiments conducted with Nellore cattle in southeast Brazil, the proposed equation (WI = 9.449 + 0.190 × MBW + 0.271 × TMAX -0.259 × HU + 0.489 × DMI, where the MBW is the metabolic BW (kg0.75), TMAX is the maximum temperature (°C), HU is the humidity (%) and DMI in kg/d), more accurately to predicts WI of cattle raised under tropical conditions.

Efficacy of sheep as a digestibility model for cattle when fed concentrate-based or forage-based diets.

The objectives were to determine the efficacy of sheep as a digestibility model for cattle feeding two diets, forage or concentrate based, under current genetics. Twelve Suffolk wethers were blocked into two periods with six wethers in each period. Within each period, wethers were fed a forage-based diet (n = 3) or a concentrate-based diet (n = 3). Six angus steers were also fed a forage-based diet (n = 3) or a concentrate-based diets (n = 3) in switchback design with two periods. All animals were adapted to diets for a minimum of 3 wk, then feed intake, refusals, and feces were collected. Feed and fecal dry matter (DM), organic matter (OM), neutral detergent fiber (NDF), acid detergent fiber (ADF), and starch were analyzed. Refusals were analyzed for DM. Data were analyzed using Proc Mixed in SAS with diet and species as fixed and period as a random effect. Dry matter intake as percentage of body weight for each animal within each period was used as a covariable. There was an interaction (P < 0.01) between species and diet for DM and OM digestibility. When fed the concentrate-based diet, DM and OM digestibility were similar between wethers and steers (P > 0.18); however, when fed the forage-based diet, DM and OM digestibility was less (P < 0.01) for wethers than steers. Like DM and OM, an interaction (P < 0.05) between species and diet was present for starch digestibility. When fed the forage-based diet, starch digestibility did not differ (P = 0.66) between wethers and steers; however, when fed concentrate-based diet, wethers had a greater starch digestibility (P < 0.05) than steers. There was no interaction (P > 0.45) between species and diet for NDF and ADF digestibility. Regardless of the diet fed, NDF and ADF digestibilities were greater (P < 0.05) in steers than wethers. Present day sheep were not a good model for cattle when fed forage-based diets, but sheep were an acceptable model for cattle when fed concentrate-based diets.

Adverse clinical and obstetric outcomes among pregnant women with different sickle cell disease genotypes.

OBJECTIVE: To compare clinical and obstetric adverse events among pregnant women with sickle cell disease (SCD) according to genotype. METHODS: The present cross-sectional study enrolled women aged 15-49 years with SCD and prior pregnancy attending a hematology center in Recife, Brazil, between September 1, 2015, and April 30, 2016. Associations between sickle cell genotype (HbSS, HbSC, Sß-thalassemia) and adverse events were evaluated. RESULTS: Overall, 89 women were included; 74 (83%) had HbSS genotype, 8 (9%) had HbSC genotype, and 7 (8%) had Sß-thalassemia genotype. Fifty-three (60%) self-reported being of mixed race, and 27 (30%) self-reported they were black. Blood transfusion was observed more frequently among women with HbSS than among those with HbSC genotype (P=0.007). Postpartum adverse events were more frequent in the Sß-thalassemia than in the HbSS group (P=0.030). Fetal intrauterine death occurred only among women with the HbSS genotype (11 [15%]). In the HbSS group, there was a higher frequency of blood transfusion (P=0.004) and lower rate of spontaneous abortion (P=0.001) among women with six or more consultations. CONCLUSION: The HbSS genotype was associated with a higher frequency of blood transfusion. Sß-thalassemia was associated with a higher frequency of postpartum adverse events. Prenatal care was associated with a lower rate of spontaneous abortion in the HbSS group.

Differential expression on mitochondrial tryparedoxin peroxidase (mTcTXNPx) in Trypanosoma cruzi after ferrocenyl diamine hydrochlorides treatments

Abstract Resistance to benznidazole in certain strains of Trypanosoma cruzi may be caused by the increased production of enzymes that act on the oxidative metabolism, such as mitochondrial tryparedoxin peroxidase which catalyses the reduction of peroxides. This work presents cytotoxicity assays performed with ferrocenyl diamine hydrochlorides in six different strains of T. cruzi epimastigote forms (Y, Bolivia, SI1, SI8, QMII, and SIGR3). The last four strains have been recently isolated from triatominae and mammalian host (domestic cat). The expression of mitochondrial tryparedoxin peroxidase was analyzed by the Western blotting technique using polyclonal antibody anti mitochondrial tryparedoxin peroxidase obtained from a rabbit immunized with the mitochondrial tryparedoxin peroxidase recombinant protein. All the tested ferrocenyl diamine hydrochlorides were more cytotoxic than benznidazole. The expression of the 25.5 kDa polypeptide of mitochondrial tryparedoxin peroxidase did not increase in strains that were more resistant to the ferrocenyl compounds (SI8 and SIGR3). In addition, a 58 kDa polypeptide was also recognized in all strains. Ferrocenyl diamine hydrochlorides showed trypanocidal activity and the expression of 25.5 kDa mitochondrial tryparedoxin peroxidase is not necessarily increased in some T. cruzi strains. Most likely, other mechanisms, in addition to the over expression of this antioxidative enzyme, should be involved in the escape of parasites from cytotoxic oxidant agents.

Trypanocidal Activity of Flavokawin B, a Component of Polygonum ferrugineum Wedd.

The trypanocidal potential of the natural chalcone flavokawin B, which was isolated from the hexanic extract of Polygonum ferrugineum Wedd., is reported here. Although flavokawin B is widespread, this is the first report about its trypanocidal properties on both Trypanosoma cruzi (IC50 = 9.5 µM, IC50 = 34.7 µM benznidazol, Y strain) epimastigotes and Trypanosoma brucei (IC50 = 4.8 µM, IC50 = 6.4 µM pentamidine, 29-13 strain) procyclic forms, which was also corroborated on T. brucei strain 427 (IC50 = 6.2 µM). In order to learn more about its properties, unspecific cytotoxicity on Hep G2 cells was investigated as well as the trans-splicing inhibitory potential on T. brucei cells. The results shown here point to flavokawin B as a candidate in the search for new agents. It is also cheaper and less toxic than the available drugs to treat trypanosomiasis with a special focus on sleeping sickness disease.

Differential expression on mitochondrial tryparedoxin peroxidase (mTcTXNPx) in Trypanosoma cruzi after ferrocenyl diamine hydrochlorides treatments.

Resistance to benznidazole in certain strains of Trypanosoma cruzi may be caused by the increased production of enzymes that act on the oxidative metabolism, such as mitochondrial tryparedoxin peroxidase which catalyses the reduction of peroxides. This work presents cytotoxicity assays performed with ferrocenyl diamine hydrochlorides in six different strains of T. cruzi epimastigote forms (Y, Bolivia, SI1, SI8, QMII, and SIGR3). The last four strains have been recently isolated from triatominae and mammalian host (domestic cat). The expression of mitochondrial tryparedoxin peroxidase was analyzed by the Western blotting technique using polyclonal antibody anti mitochondrial tryparedoxin peroxidase obtained from a rabbit immunized with the mitochondrial tryparedoxin peroxidase recombinant protein. All the tested ferrocenyl diamine hydrochlorides were more cytotoxic than benznidazole. The expression of the 25.5kDa polypeptide of mitochondrial tryparedoxin peroxidase did not increase in strains that were more resistant to the ferrocenyl compounds (SI8 and SIGR3). In addition, a 58kDa polypeptide was also recognized in all strains. Ferrocenyl diamine hydrochlorides showed trypanocidal activity and the expression of 25.5kDa mitochondrial tryparedoxin peroxidase is not necessarily increased in some T. cruzi strains. Most likely, other mechanisms, in addition to the over expression of this antioxidative enzyme, should be involved in the escape of parasites from cytotoxic oxidant agents.

The Presence, Persistence and Functional Properties of Plasmodium vivax Duffy Binding Protein II Antibodies Are Influenced by HLA Class II Allelic Variants.

BACKGROUND: The human malaria parasite Plasmodium vivax infects red blood cells through a key pathway that requires interaction between Duffy binding protein II (DBPII) and its receptor on reticulocytes, the Duffy antigen/receptor for chemokines (DARC). A high proportion of P. vivax-exposed individuals fail to develop antibodies that inhibit DBPII-DARC interaction, and genetic factors that modulate this humoral immune response are poorly characterized. Here, we investigate if DBPII responsiveness could be HLA class II-linked. METHODOLOGY/PRINCIPAL FINDINGS: A community-based open cohort study was carried out in an agricultural settlement of the Brazilian Amazon, in which 336 unrelated volunteers were genotyped for HLA class II (DRB1, DQA1 and DQB1 loci), and their DBPII immune responses were monitored over time (baseline, 6 and 12 months) by conventional serology (DBPII IgG ELISA-detected) and functional assays (inhibition of DBPII-erythrocyte binding). The results demonstrated an increased susceptibility of the DRB1*13:01 carriers to develop and sustain an anti-DBPII IgG response, while individuals with the haplotype DRB1*14:02-DQA1*05:03-DQB1*03:01 were persistent non-responders. HLA class II gene polymorphisms also influenced the functional properties of DBPII antibodies (BIAbs, binding inhibitory antibodies), with three alleles (DRB1*07:01, DQA1*02:01 and DQB1*02:02) comprising a single haplotype linked with the presence and persistence of the BIAbs response. Modelling the structural effects of the HLA-DRB1 variants revealed a number of differences in the peptide-binding groove, which is likely to lead to altered antigen binding and presentation profiles, and hence may explain the differences in subject responses. CONCLUSIONS/SIGNIFICANCE: The current study confirms the heritability of the DBPII antibody response, with genetic variation in HLA class II genes influencing both the development and persistence of IgG antibody responses. Cellular studies to increase knowledge of the binding affinities of DBPII peptides for class II molecules linked with good or poor antibody responses might lead to the development of strategies for controlling the type of helper T cells activated in response to DBPII.

Duffy antigen receptor for chemokine (DARC) polymorphisms and its involvement in acquisition of inhibitory anti-duffy binding protein II (DBPII) immunity.

The Plasmodium vivax Duffy binding protein (PvDBP) and its erythrocytic receptor, the Duffy antigen receptor for chemokines (DARC), are involved in the major P. vivax erythrocyte invasion pathway. An open cohort study to analyze DARC genotypes and their relationship to PvDBP immune responses was carried out in 620 volunteers in an agricultural settlement of the Brazilian Amazon. Three cross-sectional surveys were conducted at 6-month intervals, comprising 395, 410, and 407 subjects, respectively. The incidence rates of P. vivax infection was 2.32 malaria episodes per 100 person-months under survey (95% confidence interval [CI] of 1.92-2.80/100 person-month) and, of P. falciparum, 0.04 per 100 person-months (95% CI of 0.007-0.14/100 person-month). The distribution of DARC genotypes was consistent with the heterogeneous ethnic origins of the Amazon population, with a predominance of non-silent DARC alleles: FY*A > FY*B. The 12-month follow-up study demonstrated no association between DARC genotypes and total IgG antibodies as measured by ELISA targeting PvDBP (region II, DBPII or regions II-IV, DBPII-IV). The naturally acquired DBPII specific binding inhibitory antibodies (BIAbs) tended to be more frequent in heterozygous individuals carrying a DARC-silent allele (FY*BES). These results provide evidence that DARC polymorphisms may influence the naturally acquired inhibitory anti-Duffy binding protein II immunity.

Accumulated SET protein up-regulates and interacts with hnRNPK, increasing its binding to nucleic acids, the Bcl-xS repression, and cellular proliferation.

SET and hnRNPK are proteins involved in gene expression and regulation of cellular signaling. We previously demonstrated that SET accumulates in head and neck squamous cell carcinoma (HNSCC); hnRNPK is a prognostic marker in cancer. Here, we postulate that SET and hnRNPK proteins interact to promote tumorigenesis. We performed studies in HEK293 and HNSCC (HN6, HN12, and HN13) cell lines with SET/hnRNPK overexpression and knockdown, respectively. We found that SET and/or hnRNPK protein accumulation increased cellular proliferation. SET accumulation up-regulated hnRNPK mRNA and total/phosphorylated protein, promoted hnRNPK nuclear location, and reduced Bcl-x mRNA levels. SET protein directly interacted with hnRNPK, increasing both its binding to nucleic acids and Bcl-xS repression. We propose that hnRNPK should be a new target of SET and that SET-hnRNPK interaction, in turn, has potential implications in cell survival and malignant transformation.

Influence of volatile and nonvolatile secondary metabolites from soybean pods on feeding and on oviposition behavior of Euschistus heros (Hemiptera: Heteroptera: Pentatomidae).

Identification of chemical compounds extracted from host plants that act as oviposition stimulants for pest insects has gained importance, because of the compounds' potential use in the manipulation of insect behavior in the field. However, for generalist insects, such as phytophagous pentatomids, the chemical basis for the selection of the host is not well-known. Insect response can vary according to the soybean genotypes. Chemical profile of soybean pods of cultivars 'BRS 213', 'BRS 267', 'BR-16', and 'IAC-100' were compared regarding the feeding preference and oviposition of the stink bug Euschistus heros (F.). In the no-choice test, E. heros females showed longer feeding time on pods of BR-16 (132.6 min), followed by BRS 213 (128.0 min), BRS 267 (122.5 min), and IAC-100 (82.9 min). In the choice test, there was no significant difference in the feeding time among cultivars. In the oviposition test, females deposited 60% of eggs on the pods of BRS 267, followed by BRS 213 (27.3%), BR-16 (8.8%), and IAC-100 (3.9%). The chemical profile of BRS 267 including greater presence of reducing sugars and lack of isoflavone forms might explain the preference of E. heros to oviposite on it compared with the remaining cultivars tested.

In vitro trypanocidal activity of solamargine and extracts from Solanum palinacanthum and Solanum lycocarpum of Brazilian cerrado.

The present investigation was to evaluate the potential trypanocidal activity of crude ethanolic extract of the fruits of Solanum palinacanthum, Solanum lycocarpum and the glycoalcaloid, solamargine. S. palinacanthum and S. lycocarpum fruit powders were submitted to exhaustively extraction with 96% ethanol and solamargine were isolated from the extract of S. palinacanthum. Both extracts and solamargine were analysed for trypanocidal activity by using MTT colorimetric assay. Extracts of S. palinacanthum showed to be more active (IC50 = 175.9 µg.ml-1) than S. lycocarpum (IC50 = 194.7 µg.ml-1). Solamargine presented a strong activity (IC50 = 15.3 µg.ml-1), which can explain the better activity of the both extracts. Benznidazol (IC50 = 9.0 µg.ml-1) is the only drug used to treat Chagas' disease. These findings demonstrate for the first time that ethanol extracts obtained from both fruits of S. palinacanthum and S. lycocarpum and also solamargine have a potential anti-trypanosomal activity.

Selectivity of neem to Trichogramma pretiosum Riley and Trichogrammatoidea annulata De Santis (Hymenoptera: Trichogrammatidae)

Trichogramma pretiosum Riley and Trichogrammatoidea annulata De Santis are commonly found in avocado and persimmon orchards in northern Parana state. However, their abundance depends on whether insecticides are used or not to control the key lepidopteran pests Stenoma catenifer (Wals.) (Lepidoptera: Elachistidae) and Hypocala andremona (Stoll) (Lepidoptera: Noctuidae), respectively. The aim of this work was to evaluate the effects of an aqueous neem seed extract (ANSE) at 15, 3 and 1.5 percent, and of an emulsifiable concentrate neem oil (ECNO) at 2.5, 0.5 and 0.25 percent on lifetime parameters of these trichogrammatids as a way of testing the feasibility of integrating the biological and chemical control methods. Chemicals were applied on Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae) eggs before or after parasitization (one, three or five days). ANSE was more deleterious to both parasitoid species than ECNO, regardless of the concentration and the time of application. The chemicals acted on a concentration and time dependent manner. Treating the host with neem before parasitism was less deleterious to wasp emergence, especially for T. annulata. Pre-treatments (24h) of the host eggs with ECNO at concentrations varying from 0.5 percent to 0.25 percent did not affect T. pretiosum longevity, but 2.5 percent reduced T. annulata survival. Feeding wasps with honey mixed with 0.25 percent ECNO negatively affected T. annulata survival.

Naturally acquired antibodies to Plasmodium vivax Duffy binding protein (DBP) in Brazilian Amazon.

Duffy binding protein (DBP), a leading malaria vaccine candidate, plays a critical role in Plasmodium vivax erythrocyte invasion. Sixty-eight of 366 (18.6%) subjects had IgG anti-DBP antibodies by enzyme-linked immunosorbent assay (ELISA) in a community-based cross-sectional survey in the Brazilian Amazon Basin. Despite continuous exposure to low-level malaria transmission, the overall seroprevalence decreased to 9.0% when the population was reexamined 12 months later. Antibodies from 16 of 50 (36.0%) subjects who were ELISA-positive at the baseline were able to inhibit erythrocyte binding to at least one of two DBP variants tested. Most (13 of 16) of these subjects still had inhibitory antibodies when reevaluated 12 months later. Cumulative exposure to malaria was the strongest predictor of DBP seropositivity identified by multiple logistic regression models in this population. The poor antibody recognition of DBP elicited by natural exposure to P. vivax in Amazonian populations represents a challenge to be addressed by vaccine development strategies.

Selectivity of neem to Trichogramma pretiosum Riley and Trichogrammatoidea annulata De Santis (Hymenoptera: Trichogrammatidae).

Trichogramma pretiosum Riley and Trichogrammatoidea annulata De Santis are commonly found in avocado and persimmon orchards in northern Parana state. However, their abundance depends on whether insecticides are used or not to control the key lepidopteran pests Stenoma catenifer (Wals.) (Lepidoptera: Elachistidae) and Hypocala andremona (Stoll) (Lepidoptera: Noctuidae), respectively. The aim of this work was to evaluate the effects of an aqueous neem seed extract (ANSE) at 15, 3 and 1.5%, and of an emulsifiable concentrate neem oil (ECNO) at 2.5, 0.5 and 0.25% on lifetime parameters of these trichogrammatids as a way of testing the feasibility of integrating the biological and chemical control methods. Chemicals were applied on Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae) eggs before or after parasitization (one, three or five days). ANSE was more deleterious to both parasitoid species than ECNO, regardless of the concentration and the time of application. The chemicals acted on a concentration and time dependent manner. Treating the host with neem before parasitism was less deleterious to wasp emergence, especially for T. annulata. Pre-treatments (24h) of the host eggs with ECNO at concentrations varying from 0.5% to 0.25% did not affect T. pretiosum longevity, but 2.5% reduced T. annulata survival. Feeding wasps with honey mixed with 0.25% ECNO negatively affected T. annulata survival.