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Chagas disease, which is found widely in Latin America and has a great impact on public health, is caused by the parasite Trypanosoma cruzi . It is a neglected parasitic disease that urgently requires rapid diagnostic methods. The objective of this study was to develop a SYBR Green real-time quantitative polymerase chain reaction (qPCR) technique for the direct identification and quantification of T. cruzi from experimentally contaminated açai fruit samples. We used discrete typing units, TcI, containing 3.5 × 10 4 cells/mL, to infect the pulp of the açai fruit. This was followed by DNA extraction using a standardized procedure. The DNA samples were quantified and amplified at specific time and temperature intervals. The specificity of the oligoinitiators used in the qPCR assays was estimated by calculating the primer dissociation curve (melting curve) along with a detection threshold using different concentrations of DNA. The method used here demonstrated good efficiency and precision for the detection and quantification of T. cruzi DNA, with a detection limit of 2.65 × 10 -14 g/μL DNA. The qPCR technique presented here could serve as an important tool for the diagnosis of T. cruzi parasites in açai.

There have been significant efforts toward the development of more efficient vaccines for animal health. A strategy that may be used to improve vaccine efficacy is the use of probiotics. Bovine herpesvirus 5 (BoHV-5) is an example of an important animal pathogen for which vaccines have provided only limited protection. In this study, we examined the use of the probiotics Bacillus toyonensis and Saccharomyces boulardii as a potential immune modulator to improve vaccine efficiency. Thirty, 5-month-old lambs were randomly grouped in three lots of 10 each and vaccinated at days 0, 21 and 42 of the experiment. They grazed on the same pasture and were fed ad libitum twice a day with commercial sheep feed supplemented with either B. toyonensis (1×10 6 CFU/g of feed) or S. boulardii (1×10 7 CFU/g of feed), or non-supplemented feed. The probiotic supplementation was suspended day 28; thereafter, the next 35days, they were fed with the same commercial feed as control group. Animals supplemented with probiotics showed a significant (p>0.001) increased seroconversions against BoHV-5, and higher neutralizing antibodies titres (p>0.05) to BoHV-5 than non-supplemented animals. At 63days of experiment, splenocytes from the supplemented sheep had higher mRNA transcription levels of cytokines IL-10 and IL-17A. These results suggest that these probiotics could provide a promising means of improving vaccine efficacy., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Quorum sensing (QS) is a signaling system among bacteria mediated by auto-inducer substances (AI). Whenever the concentration of these molecules reaches a threshold corresponding to a high cell density or quorum, the whole population starts a coordinated expression of specific genes. Studies have shown that epinephrine is also responsible for activating specific bacterial genes. This work aimed to investigate the role of conditioned medium (containing AI), epinephrine and their association on growth, motility, F4 fimbriae and heat-labile toxin (LT) expression on enterotoxigenic Escherichia coli (ETEC, E68). A significant increase in motility, F4 and LT expression, was observed in the ETEC culture supplemented with conditioned medium and epinephrine. These findings suggest that ETEC uses some components of conditioned medium (e.g., AI molecules), host molecules (epinephrine), and their association to modulate the expression of important virulence genes., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Enterotoxigenic Escherichia coli (ETEC) infection is an important cause of diarrhea in both newborn and post-weaning pigs, it is also responsible for economic losses on farms worldwide. Vaccines that use ETEC virulence factors have been well documented, and several vaccines containing inactivated bacteria with protective antigens, or purified (isolated) antigens are available on the market. Vaccination of pregnant sows is widely seen as an effective strategy for the control of the disease. Yet these vaccines very often do not lead to efficient protection. In this study, we produced an ETEC bacterin with the use of quorum sensing (QS), and observed a significant expression of F4 adhesin, and heat-labile toxin (LT) in the cultures when compared to the controls. Mice, and pigs vaccinated with the QS bacterin demonstrated higher antibody titers against these antigens when compared with commercial and control bacterin. Our results suggest that the system might bring promising improvements in ETEC bacterin efficacy., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

In recent years, there been significant progress toward develop more efficient vaccines. Different compounds with adjuvant capacity have been tested; however, no compound has emerged that suitable for universal use. Several efforts have been made to produce effective vaccines against Bovine herpesvirus 5 (BoHV-5), an important cattle pathogen. In this study we examine the use the probiotic Bacillus cereus var. Toyoi as a potential adjuvant to improve BoHV-5 vaccine efficacy. We observed in the supplemented animals a systemic enhanced IgG antibody response toward Th1, and increased IFN-γ, IL-12 and IL-10 cytokines mRNA levels. These results suggest that this probiotic could provide a promising means of improving vaccine efficacy, particularly those vaccines that rely on a cell-mediated immune response., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

The amount of non-cell-associated DNA free in blood plasma from pancreatic cancer patients usually exceeds that from healthy donors. We have evaluated the plasma DNA by gel electrophoresis and measured the variation in length of soluble DNA fragments by electron microscopy in plasma from three patients with pancreatic cancer and from three healthy controls. Whereas electrophoresis of nick-translated DNA isolated from plasma obtained from healthy controls showed autoradiographic bands at sizes equivalent to whole-number multiples (1-5x) of nucleosomal DNA (185-200 bp), in the samples obtained from pancreatic cancer patients, stronger ladder patterns appeared. Likewise, strand length distributions of DNA (DNA-SL) in the two groups differ. The DNA-SL distribution data include 2,752 measurements made from cancer patient plasma and 3,291 for control plasma. The shortest DNA-SL measured approximately 30 nm (approximately 88 bp calculated at 0.34 nm/bp) and the largest approximately 28,000 nm (>80,000 bp), with 50% of all lengths measuring between 100 and 900 nm long. The average plasma DNA-SL in controls (311 nm; median, 273 nm) exceeded that in cancer patients (231 nm; median, 185 nm). Small excesses of DNA at approximately 63, approximately 126, approximately 189, approximately 252, and approximately 315 nm, corresponding to small multiples of lengths associated with nucleosomes, were more prominent in the cancer patient plasma than in the healthy control plasma. This study provides evidence indicating differences in non-cell-associated DNA in plasma between cancer patients and healthy controls and indicates that a significant amount of this DNA is probably derived from apoptosis in neoplastic and/or normal cells.

We tested whether the Steitz et al. [(1974) Proc. Natl. Acad. Sci. U.S.A., 71:593-597] model of lactose repressor (LacR) (14 x 6.0 x 4.5 nm) represented the shape of free or operator-bound LacR in solution. The model predicts a 14 nm length for bound LacR. Direct measurement, using Pt-C shadow width standards, was 9.6 +/- 0.2 nm long. Using the Steitz model, we generated a distribution of measurements and converted them into a distribution of shadow widths using gold ball standards. Direct measurement of LacR produced a narrower shadow width distribution with a larger mean size than the Steitz model predicted. Measurement along two orthogonal axes of negatively stained LacR images generated a size distribution, also converted into a shadow width distribution using the gold ball standards. Since the experimental shadow width distribution exactly matched the shadow width distribution derived theoretically from negatively stained LacR, our negative-stained images are representative of LacR's conformation in solution. Approximately 56% of negatively stained LacR had a V-shaped fold around an axis orthogonal to its length, bringing the DNA binding domains of each dimer adjacent. This open end of the V binds single operator DNA. The other 44% of the LacR tetramer is in the extended form with its DNA binding sites at opposite ends. Although the V-shaped conformation has a closed hinge with the dimers associated along a side, the extended open-hinged state remains important since LacR must bind two distant operator sites for full repression. Our measurements predict the normal presence of both conformations in nearly equal amounts, suggesting that both are equally active in repressing the lac operon.

Previous studies have described the morphology, including the ultrastructure, of primordial germ cells (PGCs), and the cells with which they associate to form the gonadal ridge, in Xenopus laevis. In order to test their capacity for active movement we have studied single, isolated PGCs in vitro. Time-lapse studies of these cells reveal that they are motile, using broad cytoplasmic processes. The fact that these cells are very large and easy to manipulate in vitro makes them an attractive subject of study, particularly with respect to the mechanism of their movement and the surface phenomena which guide them to the site of the gonadal ridge.

Rathke's pouch tissue, from rat embryos of 11-15 days' gestation, was microsurgically removed and transplanted into the hypothalamus of hypophysectomized adult females. The hosts were sacrificed 4 weeks later; brain and target organs were preserved for histological examination. Plasma samples were taken for the radioimmunoassay (RIA) of follicle stimulating hormone (FSH) and luteinizing hormone (LH). The implanted tissue invariably developed along certain lines. Undifferentiated primitive cells were found associated with nervous tissue, dense connective tissue, cartilage and glandular cells. In every age group, some implants became invasive, forming massive growths in the brain. These tumorous properties were principally associated (p less than 0.05) with tissue from 12-day embryos. Pituitary primordia from all ages demonstrated the ability to develop into functional adenohypophyseal tissue. Target organ stimulation indicated a secretion of corticotropin, thyrotropin and somatotropin. FSH and/or LH were detected by RIA in the plasma of 61% of the test animals. We suggest that this system offers unique opportunities for future investigations into the mechanisms that determine whether embryonic epithelial tissue will remain under normal growth control or will become tumorous or even cancerous.