Redox imbalance induces remodeling of glucose metabolism in Rhipicephalus microplus embryonic cell line

Carbohydrate metabolism not only functions in supplying cellular energy but also has an important role in maintaining physiological homeostasis and in preventing oxidative damage caused by reactive oxygen species. Previously, we showed that arthropod embryonic cell lines have high tolerance to H₂O₂ exposure. Here, we describe that Rhipicephalus microplus tick embryonic cell line (BME26) employs an adaptive glucose metabolism mechanism that confers tolerance to hydrogen peroxide at concentrations too high for other organisms. This adaptive mechanism sustained by glucose metabolism remodeling promotes cell survival and redox balance in BME26 cell line after millimolar H₂O₂ exposure. The present work shows that this tick cell line could tolerate high H₂O₂ concentrations by initiating a carbohydrate-related adaptive response. We demonstrate that gluconeogenesis was induced as a compensation strategy that involved, among other molecules, the metabolic enzymes NADP-ICDH, G6PDH, and PEPCK. We also found that this phenomenon was coupled to glycogen accumulation and glucose uptake, supporting the pentose phosphate pathway to sustain NADPH production and leading to cell survival and proliferation. Our findings suggest that the described response is not atypical, being also observed in cancer cells, which highlights the importance of this model to all proliferative cells. We propose that these results will be useful in generating basic biological information to support the development of new strategies for disease treatment and parasite control.     

Epidemiological surveillance of birth defects compatible with thalidomide embryopathy in Brazil

The thalidomide tragedy of the 1960s resulted in thousands of children being born with severe limb reduction defects (LRD), among other malformations. In Brazil, there are still babies born with thalidomide embryopathy (TE) because of leprosy prevalence, availability of thalidomide, and deficiencies in the control of drug dispensation. Our objective was to implement a system of proactive surveillance to identify birth defects compatible with TE. Along one year, newborns with LRD were assessed in the Brazilian hospitals participating in the Latin-American Collaborative Study of Congenital Malformations (ECLAMC). A phenotype of LRD called thalidomide embryopathy phenotype (TEP) was established for surveillance. Children with TEP born between the years 2000-2008 were monitored, and during the 2007-2008 period we clinically investigated in greater detail all cases with TEP (proactive period). The period from 1982 to 1999 was defined as the baseline period for the cumulative sum statistics. The frequency of TEP during the surveillance period, at 3.10/10,000 births (CI 95%: 2.50-3.70), was significantly higher than that observed in the baseline period (1.92/10,000 births; CI 95%: 1.60-2.20), and not uniformly distributed across different Brazilian regions. During the proactive surveillance (2007-2008), two cases of suspected TE were identified, although the two mothers had denied the use of the drug during pregnancy. Our results suggest that TEP has probably increased in recent years, which coincides with the period of greater thalidomide availability. Our proactive surveillance identified two newborns with suspected TE, proving to be a sensitive tool to detect TE. The high frequency of leprosy and the large use of thalidomide reinforce the need for a continuous monitoring of TEP across Brazil.     

Signaling mechanisms mediating BDNF modulation of memory formation in vivo in the hippocampus

Given that brain-derived neutrophic factor (BDNF) modulates both short-term synaptic function and activity-dependent synaptic plasticity in the adult hippocampus, here we examined signaling mechanisms in vivo in the hippocampus mediating BDNF modulation of long-term memory (LTM) formation of a one-trial fear-motivated learning task in rats. Bilateral infusions of function-blocking anti-BDNF antibody into the CA1 region of the dorsal hippocampus decreased extracellular-signal regulated kinase 2 (ERK2) and CREB activation and impaired LTM retention scores. Inhibition of ERK1/2 activation by PD098059 produced similar effects and also reduced CREB phosphorylation. In contrast, intrahippocampal administration of recombinant human BDNF increased ERK1/2 and CREB activation and facilitated LTM. Activated-p38, activated-PKC isoforms, and activated-AKT were unaltered after BDNF or anti-BDNF infusion. In addition, no changes were found on PKA and PKA catalytic subunits in nuclear samples. Thus, our results suggest that BDNF exerts its role in LTM formation in vivo in CA1 region of the hippocampus, at least in part, via CREB activation. Moreover, BDNF-induced CREB activation appears to be mediated mainly through the activation of ERK1/2 signaling pathway.     

Exercise training in childhood-onset systemic lupus erythematosus: a controlled randomized trial

Introduction

Exercise training has emerged as a promising therapeutic strategy to counteract physical dysfunction in adult systemic lupus erythematosus. However, no longitudinal studies have evaluated the effects of an exercise training program in childhood-onset systemic lupus erythematosus (C-SLE) patients. The objective was to evaluate the safety and the efficacy of a supervised aerobic training program in improving the cardiorespiratory capacity in C-SLE patients.

Methods

Nineteen physically inactive C-SLE patients were randomly assigned into two groups: trained (TR, n = 10, supervised moderate-intensity aerobic exercise program) and non-trained (NT, n = 9). Gender-, body mass index (BMI)- and age-matched healthy children were recruited as controls (C, n = 10) for baseline (PRE) measurements only. C-SLE patients were assessed at PRE and after 12 weeks of training (POST). Main measurements included exercise tolerance and cardiorespiratory measurements in response to a maximal exercise (that is, peak VO₂, chronotropic reserve (CR), and the heart rate recovery (ΔHRR) (that is, the difference between HR at peak exercise and at both the first (ΔHRR1) and second (ΔHRR2) minutes of recovery after exercise).

Results

The C-SLE NT patients did not present changes in any of the cardiorespiratory parameters at POST (P > 0.05). In contrast, the exercise training program was effective in promoting significant increases in time-to-exhaustion (P = 0.01; ES = 1.07), peak speed (P = 0.01; ES = 1.08), peak VO₂ (P = 0.04; ES = 0.86), CR (P = 0.06; ES = 0.83), and in ΔHRR1 and ΔHRR2 (P = 0.003; ES = 1.29 and P = 0.0008; ES = 1.36, respectively) in the C-SLE TR when compared with the NT group. Moreover, cardiorespiratory parameters were comparable between C-SLE TR patients and C subjects after the exercise training intervention, as evidenced by the ANOVA analysis (P > 0.05, TR vs. C). SLEDAI-2K scores remained stable throughout the study.

Conclusion

A 3-month aerobic exercise training was safe and capable of ameliorating the cardiorespiratory capacity and the autonomic function in C-SLE patients.

Trial registration

NCT01515163.     

Towards a framework for the evolutionary genomics of Kinetoplastids: what kind of data and how much?

The current status of kinetoplastids phylogeny and evolution is discussed in view of the recent progresses on genomics. Some ideas on a potential framework for the evolutionary genomics of kinetoplastids are presented.     

Improving model construction of profile HMMs for remote homology detection through structural alignment

Background  

Remote homology detection is a challenging problem in Bioinformatics. Arguably, profile Hidden Markov Models (pHMMs) are one of the most successful approaches in addressing this important problem. pHMM packages present a relatively small computational cost, and perform particularly well at recognizing remote homologies. This raises the question of whether structural alignments could impact the performance of pHMMs trained from proteins in the Twilight Zone, as structural alignments are often more accurate than sequence alignments at identifying motifs and functional residues. Next, we assess the impact of using structural alignments in pHMM performance.     

Automated Entire Thrombus Density Measurements for Robust and Comprehensive Thrombus Characterization in Patients with Acute Ischemic Stroke

Background and Purpose

In acute ischemic stroke (AIS) management, CT-based thrombus density has been associated with treatment success. However, currently used thrombus measurements are prone to inter-observer variability and oversimplify the heterogeneous thrombus composition. Our aim was first to introduce an automated method to assess the entire thrombus density and then to compare the measured entire thrombus density with respect to current standard manual measurements.

Materials and Method

In 135 AIS patients, the density distribution of the entire thrombus was determined. Density distributions were described using medians, interquartile ranges (IQR), kurtosis, and skewedness. Differences between the median of entire thrombus measurements and commonly applied manual measurements using 3 regions of interest were determined using linear regression.

Results

Density distributions varied considerably with medians ranging from 20.0 to 62.8 HU and IQRs ranging from 9.3 to 55.8 HU. The average median of the thrombus density distributions (43.5 ± 10.2 HU) was lower than the manual assessment (49.6 ± 8.0 HU) (p<0.05). The difference between manual measurements and median density of entire thrombus decreased with increasing density (r = 0.64; p<0.05), revealing relatively higher manual measurements for low density thrombi such that manual density measurement tend overestimates the real thrombus density.

Conclusions

Automatic measurements of the full thrombus expose a wide variety of thrombi density distribution, which is not grasped with currently used manual measurement. Furthermore, discrimination of low and high density thrombi is improved with the automated method.     

Isolation and characterization of two binding proteins for advanced glycosylation end products from bovine lung which are present on the endothelial cell surface.

Nonenzymatic glycosylation of proteins, as occurs at an accelerated rate in diabetes, can lead to the formation of advanced glycosylation end products of proteins (AGEs), which can bind to endothelial cells, thereby altering cellular function in a manner which could contribute to the pathogenesis of diabetic angiopathy. In this report, we describe the isolation of two endothelial cell surface-associated proteins which mediate, at least in part, the interaction of AGEs with endothelium. Based on pilot studies demonstrating AGE binding activity with comparable characteristics in bovine endothelial cell and lung extracts, the material from lung was sequentially subjected to chromatography on hydroxylapatite, fast protein liquid chromatography Mono S, and gel filtration. Two distinct polypeptides, approximately 35 and approximately 80 kDa, were purified to homogeneity, each of which bound AGEs as demonstrated by competitive binding assays using cellular binding proteins immobilized on a plastic surface. NH2-terminal sequence analysis indicated that the approximately 35-kDa protein was novel, whereas the NH2-terminal sequence of the approximately 80-kDa protein was identical to that of lactoferrin. Immunocytologic studies using polyclonal antibody prepared to each of the purified polypeptides demonstrated the presence of immunoreactive material on the surface of bovine endothelial cells maintained under serum-free conditions. Furthermore, immunoelectron microscopic studies with antibodies to the approximately 35- and approximately 80-kDa AGE-binding proteins conjugated to different size colloidal gold particles confirmed the presence of the target antigens on the cell surface and suggested that they were closely associated. IgG purified from polyclonal antisera to either the 35- or 80-kDa AGE-binding proteins blocked the binding of 125I-AGE-albumin to the cell surface. These results indicate that endothelial cells express specific cell surface molecules which mediate AGE-endothelial interaction. These polypeptides represent a novel class of cell surface acceptor molecules for glucose-modified proteins which may promote degradation and/or transcytosis of the ligand, and modulation of cellular function.     

Biofilm formation and antimicrobial sensitivity of lactobacilli contaminants from sugarcane-based fuel ethanol fermentation

Industrial ethanol fermentation is subject to bacterial contamination that causes significant economic losses in ethanol fuel plants. Chronic contamination has been associated with biofilms that are normally more resistant to antimicrobials and cleaning efforts than planktonic cells. In this study, contaminant species of Lactobacillus isolated from biofilms (source of sessile cells) and wine (source of planktonic cells) from industrial and pilot-scale fermentations were compared regarding their ability to form biofilms and their sensitivity to different antimicrobials. Fifty lactobacilli were isolated and the most abundant species were Lactobacillus casei, Lactobacillus fermentum and Lactobacillus plantarum. The majority of the isolates (87.8%) were able to produce biofilms in pure culture. The capability to form biofilms and sensitivity to virginiamycin, monensin and beta-acids from hops, showed inter- and intra-specific variability. In the pilot-scale fermentation, Lactobacillus brevis, L. casei and the majority of L. plantarum isolates were less sensitive to beta-acids than their counterparts from wine; L. brevis isolates from biofilms were also less sensitive to monensin when compared to the wine isolates. Biofilm formation and sensitivity to beta-acids showed a positive and negative correlation for L. casei and L. plantarum, respectively.