Leishmania (Leishmania) infantum/chagasi: Histopathological aspects of the skin in naturally infected dogs in two endemic areas

In the New World, visceral leishmaniasis (VL), which is a progressive disease and frequently fatal, is caused by Leishmania (Leishmania) infantum/chagasi. It is endemic in many regions of Brazil and occasionally occurs in non-endemic regions when dogs from an endemic area are introduced. The aim of the present study is to compare different skin infection patterns of dogs from two leishmaniasis endemic areas. A histological analysis of dogs from Campo Grande, Mato Grosso do Sul state, a region where epidemic episodes are currently taking place, showed dermic inflammatory infiltrates, composed of numerous vacuolated parasitized macrophages, few lymphocytes, plasma cells and many degranulated mast cells. In the other region of the study, São Luís, Maranhão state, the skin of dogs presented a remarkable inflammatory reaction composed mainly of plasma cells, lymphocytes and very few parasites. We concluded that there is a difference in the skin lesion patterns of dogs with leishmaniasis that is directly related to the endemic area where the animals live.     

In Candida albicans hyphae,Sec2p is physically associated with SEC2 mRNA on secretory vesicles

Candida albicans hyphae grow in a highly polarized fashion from their tips. This polarized growth requires the continuous delivery of secretory vesicles to the tip region. Vesicle delivery depends on Sec2p, the Guanine Exchange Factor (GEF) for the Rab GTPase Sec4p. GTP bound Sec4p is required for the transit of secretory vesicles from the trans‐Golgi to sites of polarized growth. We previously showed that phosphorylation of Sec2p at residue S584 was necessary for Sec2p to support hyphal, but not yeast growth. Here we show that on secretory vesicles SEC2 mRNA is physically associated with Sec2p. Moreover, we show that the phosphorylation of S584 allows SEC2 mRNA to dissociate from Sec2p and we speculate that this is necessary for Sec2p function and/or translation. During hyphal extension, the growing tip may be separated from the nucleus by up to 15 μm. Transport of SEC2 mRNA on secretory vesicles to the tip localizes SEC2 translation to tip allowing a sufficient accumulation of this key protein at the site of polarized growth.     

Structural and biological characterization of Nattectin, a new C-type lectin from the venomous fish Thalassophryne nattereri

Lectins are glycan-binding receptors that recognize glycan epitopes on foreign pathogens and in the host systems. They can be involved in functions that include innate immunity, development, immune regulation and homeostasis. Several lectins have been purified and characterized from fish species. In this work, using cation-exchange chromatography, a galactose-specific lectin belonging to the family of C-type lectins was isolated from the venom of the Brazilian venomous fish Thalassophryne nattereri. Nattectin is a basic, non-glycosilated, 15 kDa monomeric protein. It exhibits hemagglutination activity that is independent of Ca²⁺. We also demonstrated a lectin activity for Nattectin in the innate immune system, especially in neutrophil mobilization in mice, indicating that marine organisms are source of immunomodulator agents.     

Patient's cells colonize the biofilm of Tenckhoff catheters used in peritoneal dialysis

Peritoneal dialysis (PD) is a renal substitutive therapy based on the infusion of a dialysate in the peritoneum, which induces through an osmotic gradient the ultrafiltration of water and the clearance of blood stream impurities by the peritoneal membrane. The colonization of Tenckhoff catheters (TCs) used in PD by pathogenic microorganisms can lead to peritonitis, and probably catheter removal. Here, optical microscopy and scanning electron microscopy were applied to study biofilm formation in 11 TCs. Biofilms varied in their morphology and thickness. Short-term catheters (6 months) presented thinner deposits (3 μm) with granular or flat morphologies, either on the intraluminal or external surfaces. Bacterial colonies were found on catheters from infected patients. A tendency was observed for long-term catheters (6-8 years) to present thicker biofilms (30-35 μm). Surprisingly, patients' cells colonized the deep layers of the thicker biofilms, forming a complex multicelullar community. It was concluded that the presence of a biofilm is not necessarily related with peritonitis, and biofilm features may correlate to the therapy time.     

RAPD and ISSR markers in the evaluation of genetic divergence among accessions of elephant grass

Considering the expected genetic variability of elephant grass (Pennisetum purpureum), due to its cultivation in different continents, we characterized and estimated the genetic divergences between 46 accessions of elephant grass with different edaphoclimatic adaptations, using RAPD and ISSR markers. We evaluated, comparatively, the consistency of the information achieved with these markers. Twenty-six RAPD and 25 ISSR primers were employed. The RAPD markers produced 185 bands, 72% of which were polymorphic, with a mean of 5.11 polymorphic bands per primer. The 25 ISSR starters produced 216 bands; 76% were polymorphic, with a mean of 6.56 polymorphic bands per primer. The correlation between the genetic distances achieved by the RAPD and ISSR markers was 0.76, which is highly significant by the Mantel test. Based on UPGMA grouping, considering the point of sudden change, five and six groups were formed for the data from the RAPD and ISSR markers, respectively. These markers provided partially concordant groups, indicating that these techniques can provide consistent information and consequently could be used in studies of genetic diversity among accessions.     

Carvedilol Prevents Ovariectomy-Induced Myocardial Contractile Dysfunction in Female Rat

Carvedilol has beneficial effects on cardiac function in patients with heart failure but its effect on ovariectomy-induced myocardial contractile dysfunction remains unclear. Estrogen deficiency induces myocardial contractile dysfunction and increases cardiovascular disease risk in postmenopausal women. Our aim was to investigate whether carvedilol, a beta receptor blocker, would prevent ovariectomy-induced myocardial contractile dysfunction. Female rats (8 weeks old) that underwent bilateral ovariectomy were randomly assigned to receive daily treatment with carvedilol (OVX+CAR, 20 mg/kg), placebo (OVX) and SHAM for 58 days. Left ventricle papillary muscle was mounted for isometric tension recordings. The inotropic response to Ca²⁺ (0.62 to 3.75 mM) and isoproterenol (Iso 10⁻⁸ to 10⁻² M) were assessed. Expression of calcium handling proteins was measured by western blot analysis. Carvedilol treatment in the OVX animals: prevented weight gain and slight hypertrophy, restored the reduced positive inotropic responses to Ca²⁺ and isoproterenol, prevented the reduction in SERCA2a expression, abolished the increase in superoxide anion production, normalized the increase in p22^phox expression, and decreased serum angiotensin converting enzyme (ACE) activity. This study demonstrated that myocardial contractile dysfunction and SERCA2a down regulation were prevented by carvedilol treatment. Superoxide anion production and NADPH oxidase seem to be involved in this response.     

Susceptibility of Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) adults to fungicides used to control apple diseases

This study evaluated the susceptibility under laboratory conditions of Trichogrammapretiosum Riley adults to fungicides recommended by the Integrated Production of Apple (IPA). The bioassays were carried out using the International Organization for Biological Control (IOBC), West Palearctic Regional Section (WPRS) standard protocols. Twelve selected fungicides were studied in the doses (g or ml active ingredient/100 L) captan 1 (0.115), captan 2 (0.120), kresoxim-methyl (0.010), sulphur 1 (AG) (0.480), sulphur 2 (0.480), folpet (0.105), mancozeb (0.160), pyraclostrobin (0.010), tebuconazole (0.010), tetraconazole (0.005), thiophanate-methyl (0.050) and triforine (0.024). Distilled water was used as the blank treatment and the insecticide triclorfon (0.150) as a positive control. The parasitoids were exposed to dry residues applied on glass plates. The reduction in the capacity of parasitism was used to measure the effect of the chemical in comparison to the blank treatment. Each treatment was replicated four times. The results allowed us to classify the fungicides tested in four categories: 1, harmless (< 30%); 2, slightly harmful (30-79%); 3, moderately harmful (80-99%); and 4, harmful (> 99%). 75% of the tested substances were classified as selective (classes 1 and 2) to the parasitoid. The fungicides captan 1, captan 2, kresoxim-methyl, folpet, pyraclostrobin, tebuconazole, thiophanate-methyl and triforine were harmless; mancozeb was slightly harmful; sulphur 1 (AG) and tetraconazole were moderately harmful and sulphur 2 was harmful. These findings should be taken into account when selecting fungicides to spray apple orchards against fungi diseases to preserve the egg parasitoid T. pretiosum.     

Helicobacter pylori antimicrobial resistance in a pediatric population

Background

The increasing prevalence of Helicobacter pylori (H. pylori) antimicrobial resistance, primarily for clarithromycin decreases the success of treatment. The aim of this study is to determine the local pattern of first‐line antimicrobials resistance and the eradication rate.

Material and Methods

Prospective cohort study of H. pylori infected patients (positive histological or cultural exams) treated at Centro Materno‐Infantil do Norte from January of 2013 to October of 2017. Susceptibility to 4 antibiotics: amoxicilin, metronidazole, clarithromycin, and levofloxacin were analyzed by E‐test (phenotypic resistance). The E‐test was chosen because it is simple and cost‐effective for routine susceptibility testing. Point mutations that confer clarithromycin resistance were surveyed (genotypic resistance). Eradication of H. pylori infection was defined by a negative urea breath test or fecal antigen 6‐8 weeks after the end of treatment.

Results

Of a total of 74 H. pylori infected patients, 16 were excluded because they had previous H. pylori treatment or severe systemic disease. Median age of infection cases was 15 years (3‐17 years). Eradication regimen used in all patients combined the use of 3 antibiotics (amoxicillin and metronidazole or clarithromycin) and proton pump inibhitor for 14 days and was tailored according antimicrobial susceptibility. 79.5% of the patients completed the treatment. The resistance rate for metronidazole and clarithromycin was 3.3% and 23.3%, respectively. There was no resistance for amoxicilin and levofloxacin. The rate of genotypic resistance to clarithromycin was 37.2%. The eradication rate was 97.8%.

Conclusions

The authors found a high resistance rate of H. pylori for clarithromycin in this northern portuguese pediatric center. This factor should determine a change in local current treatment, contraindicating the use of clarithromycin as a first‐line treatment for H. pylori infection in children. The high eradication rate maybe explained for the eradication treatment tailored according antimicrobial susceptibility.     

Babassu palm (Attalea speciosa Mart.) super-dominance shapes its surroundings via multiple biotic,soil chemical,and physical interactions and accumulates soil carbon: a case study in eastern Amazonia

Plant and Soil - Aggressive ruderal plant species pose an increasing problem in anthropically degraded lands. They both affect and are affected by other vegetation and by soil fertility in their...