Detection of Soluble Antigen and DNA of Trypanosoma cruzi in Urine Is Independent of Renal Injury in the Guinea Pig Model

The diagnosis of Chagas disease in humans is generally limited to the detection of specific antibodies. Detection of T. cruzi antigens in urine has been reported previously, but is not used in the diagnosis. In this study, soluble T. cruzi antigens and DNA were detected in urine samples and were associated with kidney injury and systemic detection of the parasite. We used 72 guinea pigs infected with T. cruzi Y strain and 18 non-infected guinea pigs. Blood, kidney, heart and urine samples were collected during the acute phase and chronic phase. Urine samples were concentrated by ultrafiltration. Antigens were detected by Western Blot using a polyclonal antibody against trypomastigote excretory-secretory antigen (TESA). T. cruzi DNA was detected by PCR using primers 121/122 and TcZ1/TcZ2. Levels of T. cruzi DNA in blood, heart and kidney were determined by quantitative PCR. T. cruzi antigens (75 kDa, 80 kDa, 120 kDa, 150 kDa) were detected in the acute phase (67.5%) and the chronic phase (45%). Parasite DNA in urine was detected only in the acute phase (45%). Kidney injury was characterized by high levels of proteinuria, kidney injury molecule-1 (KIM-1) and urea, and some histopathological changes such as inflammation, necrosis, fibrosis and scarce parasites. The detection of antigens and DNA in urine was associated with the presence of parasite DNA in blood and heart and with high levels of parasite DNA in blood, but not with the presence of parasite in kidney or kidney injury. These results suggest that the detection of T. cruzi in urine could be improved to be a valuable method for the diagnosis of Chagas disease, particularly in congenital Chagas disease and in immunocompromised patients.     

Isolation and characterization of new facultative alkaliphilic Bacillus flexus strains from maize processing waste water (nejayote)

Aims: This work describes the isolation and characterization of two new alkaliphilic micro‐organisms present in nejayote. Methods and Results: Samples of fresh industrial nejayote were plated on nejayote medium and incubated for 4 days at 37°C. Isolates were identified based on morphological and physiological characteristics, as well as 16S rDNA sequence analysis. Two gram‐positive strains, NJY2 and NJY4, able to hydrolyse starch, xylan, and gelatin were isolated from nejayote. Comparative sequence analysis of 16S rDNA and phylogenetic studies indicate that the micro‐organisms studied were closely related to members of the Bacillus flexus species. The strains were identified as facultative alkaliphilic salt tolerant bacteria. Isolate NJY2 produced cell associated phenolic acid esterases, able to release ferulic acid from nixtamalised corn bran and ethyl and methyl esters. Conclusions: The isolated strains of B. flexus NJY2 and NJY4 showed important physiological properties to produce high‐value molecules from agroindustrial by‐products. Significance and Impact of the Study: This is the first report about the isolation of alkaliphilic micro‐organisms from nejayote and the first report of phenolic acid esterases synthesised by alkaliphiles. The new alkaliphilic micro‐organisms have potential application in the treatment and transformation of tortilla industry residues.     

Nitrogen and potassium variation on contaminant removal for a vertical subsurface flow lab scale constructed wetland

Lab scale constructed wetlands were used to evaluate organic load removal efficiency. Bioreactors were fed with synthetic wastewater (SW) with varying concentrations of nitrogen and potassium. Reactors were planted with species Phragmites australis. Fed theoretic COD was adjusted to 240.0 mg-O₂ L⁻¹, nitrogen levels were 10 and 40 mg-N L⁻¹ (ammonium sulfate), potassium levels were 5 and 31 mg-K L⁻¹ (potassium monobasic phosphate). The higher biomass yield, for 0.5 and 0.775 N:K ratios, was related with higher organic load removal. The ratio N:K showed significant differences for organic load abatement, when 1:0.5 and 1:0.775 N:K ratios were applied, 96.8% efficiency was obtained, whereas N:K ratio of 1:0.125 had efficiency of 92.1% and N:K ratio of 1:3.1 showed an efficiency of 90.5%. For planted bioreactor E_H decreased in 162.7 mV from sample port to 5 cm down to 35 cm depth, while for the bioreactor without plant showed an E_H decrement of only 17.7 mV.     

Pancreatic insulin secretion in rats fed a soy protein high fat diet depends on the interaction between the amino acid pattern and isoflavones

Obesity is frequently associated with the consumption of high carbohydrate/fat diets leading to hyperinsulinemia. We have demonstrated that soy protein (SP) reduces hyperinsulinemia, but it is unclear by which mechanism. Thus, the purpose of the present work was to establish whether SP stimulates insulin secretion to a lower extent and/or reduces insulin resistance, and to understand its molecular mechanism of action in pancreatic islets of rats with diet-induced obesity. Long-term consumption of SP in a high fat (HF) diet significantly decreased serum glucose, free fatty acids, leptin, and the insulin:glucagon ratio compared with animals fed a casein HF diet. Hyperglycemic clamps indicated that SP stimulated insulin secretion to a lower extent despite HF consumption. Furthermore, there was lower pancreatic islet area and insulin, SREBP-1, PPARgamma, and GLUT-2 mRNA abundance in comparison with rats fed the casein HF diet. Euglycemic-hyperinsulinemic clamps showed that the SP diet prevented insulin resistance despite consumption of a HF diet. Incubation of pancreatic islets with isoflavones reduced insulin secretion and expression of PPARgamma. Addition of amino acids resembling the plasma concentration of rats fed casein stimulated insulin secretion; a response that was reduced by the presence of isoflavones, whereas the amino acid pattern resembling the plasma concentration of rats fed SP barely stimulated insulin release. Infusion of isoflavones during the hyperglycemic clamps did not stimulate insulin secretion. Therefore, isoflavones as well as the amino acid pattern seen after SP consumption stimulated insulin secretion to a lower extent, decreasing PPARgamma, GLUT-2, and SREBP-1 expression, and ameliorating hyperinsulinemia observed during obesity.     

Vmp1 Regulates PtdIns3P Signaling During Autophagosome Formation in Dictyostelium discoideum

Generation and turnover of phosphatidylinositol 3‐phosphate (PtdIns3P) signaling is essential for autophagosome formation and other membrane traffic processes. In both Dictyostelium discoideum and mammalian cells, autophagosomes are formed from specialized regions of the endoplasmic reticulum (ER), called omegasomes, which are enriched in the signaling lipid PtdIns3P. Vacuole membrane protein 1 (Vmp1) is a multispanning membrane protein localized at the ER that is required for autophagosome formation. There are conflicting reports in the literature as to whether Vmp1 is strictly required or not for autophagy‐related PtdIns3P signaling and its hierarchical relationship with Atg1 and PI3K. We have now addressed these questions in the Dictyostelium model. We show that Dictyostelium cells lacking Vmp1 have elevated and aberrant PtdIns3P signaling on the ER, resulting in an increased and persistent recruitment of Atg18 and other autophagic proteins. This indicates that Vmp1 is not strictly essential for the generation of PtdIns3P signaling but rather suggests a role in the correct turnover or modulation of this signaling. Of interest, these PtdIns3P‐enriched regions of the ER surround ubiquitinated protein aggregates but are unable to form functional autophagosomes. vmp1 null cells also have additional defects in macropinocytosis and growth, which are not shared by other autophagy mutants. Remarkably, we show that these defects and also the aberrant PtdIns3P distribution are largely suppressed by the concomitant loss of Atg1, indicating that aberrant autophagic signaling on the ER inhibits macropinocytosis. These results suggest that Atg1 functions upstream of Vmp1 in this signaling pathway and demonstrates a previously unappreciated link between abnormal autophagy signaling and macropinocytosis.      

The type of leg lost affects habitat use but not survival in a non‐regenerating arthropod

Finding shelter and surviving encounters with predators are pervasive challenges for animals. These challenges may be exacerbated after individuals experience bodily damage. Certain forms of damage arise voluntarily in animals; for instance, some taxa release appendages (tails, legs, or other body parts) as a defensive strategy (“autotomy”). This behavior, however, may pose long‐term negative consequences for habitat use and survival. Additionally, these putative consequences are expected to vary according to the function of the lost body part. We tested the effects of losing different functional leg types (locomotor or sensory) on future habitat use and survival in a Neotropical species of Prionostemma harvestmen (Arachnida: Opiliones) that undergo frequent autotomy but do not regrow limbs. Daytime surveys revealed that both eight‐legged harvestmen and harvestmen missing legs roosted in similar frequencies across habitats (tree bark, mossy tree, or fern), and perched at similar heights. Mark–recapture data showed that harvestmen that lost sensory legs roosted in tree bark less frequently, but on mossy trees more frequently. On the contrary, we did not observe changes in habitat use for eight‐legged animals or animals that lost locomotor legs. This change might be related to sensory exploration and navigation. Lastly, we found that recapture rates across substrates were not affected by the type of legs lost, suggesting that leg loss does not impact survival. This potential lack of effect might play a role in why a defensive strategy like autotomy is so prevalent in harvestmen despite the lack of regeneration.     

Efficacy of IgG and F(ab')2 antivenoms to neutralize snake venom-induced local tissue damage as assessed by the proteomic analysis of wound exudate

Proteomic analysis of wound exudates represents a valuable tool to investigate tissue pathology and to assess the therapeutic success of various interventions. In this study, the ability of horse-derived IgG and F(ab')(2) antivenoms to neutralize local pathological effects induced by the venom of the snake Bothrops asper in mouse muscle was investigated by the proteomic analysis of exudates collected in the vicinity of affected tissue. In experiments involving the incubation of venom and antivenom prior to injection in mice, hemorrhagic activity was completely abolished and local muscle-damaging activity was significantly reduced by the antivenoms. In these conditions, the relative amounts of several intracellular and extracellular matrix proteins were reduced by the action of antivenoms, whereas the relative amounts of various plasma proteins were not modified. Because not all intracellular proteins were reduced, it is likely that there is a residual cytotoxicity not neutralized by antivenoms. In experiments designed to more closely reproduce the actual circumstances of envenoming, that is, when antivenom is administered after envenomation, the number of proteins whose amounts in exudates were reduced by antivenoms decreased, underscoring the difficulty in neutralizing local pathology due to the very rapid onset of venom-induced pathology. In these experiments, IgG antivenom was more efficient than F(ab')(2) antivenom when administered after envenomation, probably as a consequence of differences in their pharmacokinetic profiles.     

Cyclooxygenase-2 and kidney failure

Cyclooxygenase (COX)-dependent prostaglandins are necessary for normal kidney function. These prostaglandins are associated with inflammation, maintenance of sodium and water homeostasis, control of renin release, renal vasodilation, vasoconstriction attenuation, and prenatal renal development. COX-2 expression is regulated by the renin-angiotensin system, glucocorticoids or mineralcorticoids, and aldosterone, supporting a role for COX-2 in kidney function. Indeed, COX-2 mRNA and protein levels as well as enzyme activity are increased, along with PGE2, during kidney failure. In addition, changes in COX-2 expression are associated with increased blood pressure, urinary volume, sodium and protein and decreased urinary osmolarity. Intrarenal mechanisms such as angiotensin II (Ang II) production, increased sodium delivery, glomerular hypertension, and renal tubular inflammation have been suggested to be responsible for the increase in COX-2 expression. Although, specific COX-2 pharmacological inhibition has been related to the prevention of kidney damage, clinical studies have reported that COX-2 inhibition may cause side effects such as edema or a modest elevation in blood pressure and could possibly interfere with antihypertensive drugs and increase the risk of cardiovascular complications. Thus, administration of COX-2 inhibitors requires caution, especially in the presence of underlying cardiovascular disease.