Selective recovery of xylanase from Penicillium janthinellum using BDBAC reversed micelles

A xylanase was removed from crude extract of the fungus Penicillium janthinellum under optimized conditions: 0.10M phosphate buffer, pH 7.0, 0.2 M BDBAC (N-benzyl-N-dodeceyl-N-bis (2-hydroxyethyl) ammonium chloride), 7.5% hexanole, 30°C and an agitation time of 1 minute. At 1.42 mg per ml protein concentration, 73% of the xylanase activity was recovered and a 7-fold enrichment factor was obtained. The enzyme had a molecular weight (MW) of 20.1 kDa and the isoelectric point (PI) revealed the presence of two protein bands with a PI of 6.0 and 6.5. The optimum pH and optimum temperature were 4.2 and 50°C, respectively. The low pH differential between the aqueous medium and the protein PI seemed to influence the xylanase transportation into the reversed micelles.     

Prostaglandin F2α promotes ovulation in prepubertal heifers

The objective was to determine the effects of exogenous prostaglandin F_2α (PGF), with or without progesterone treatment, on first ovulation in prepubertal heifers. We tested the hypothesis that PGF has a luteolysis-independent ovulatory effect in cattle. Crossbred Angus heifers (12 to 14 mo old, 250 kg body weight, and an average body condition score of 3 out of 5) were examined by transrectal ultrasonography on two occasions, 11 days apart. Heifers in which a CL was not detected at either examination were considered prepubertal. Heifers were assigned randomly to three experimental groups: (1) PG group (N = 14); heifers were treated with a PGF analog (500 μg cloprostenol im) 5 days after the emergence of a spontaneous (i.e., naturally occurring, noninduced) follicular wave; (2) PPG group (N = 12); heifers were given an intravaginal progesterone-releasing insert (CIDR; Pfizer Animal Health, Montreal, QC, Canada), and a follicular wave was induced with 50 mg of progesterone + 2 mg of estradiol benzoate im, and a PGF analog was given at the time of CIDR removal, on Day 5 of the follicular wave (on average, 8.6 ± 0.5 days after CIDR insertion); and (3) control group heifers were given no treatment (N = 14). Heifers were examined daily by transrectal ultrasonography from the start of the experiment to confirmation that ovulation had occurred, or to 5 days after PGF injection (PG and PPG groups) or until dominant follicles of the next follicular wave reached 8 mm (control group). The percentage of heifers that ovulated within 10 days after wave emergence was higher in PPG (10/12; 83.3%) and PG (11/14; 78.5%) groups than in control (1/14; 7.1%; P < 0.0001). Ovulations occurred 69.6 ± 6 h and 93.8 ± 5 h after PGF treatment in PPG and in PG groups, respectively, whereas only one heifer in the control group ovulated 96 h after Day 5 of follicular wave (P = 0.13). In summary, PGF treatment was associated with ovulation in prepubertal heifers whether or not exogenous progesterone was used as a pretreatment. The hypothesis that PGF will induce ovulation by a luteolysis-independent mechanism was supported.     

Single-chain antibody fragments: Purification methodologies

At present, single-chain variable fragments (scFv) of antibodies are considered one of the most important tools in human therapies. Wide applications of antibodies are being exploited in different medical, pharmaceutical and research areas. These molecules maintain the same binding functionality that full length antibodies but possess several advantageous features as quickness to penetrate the tissues, easy manipulation, fast elimination of their immunocomplex and the possibility of being produced in simple expression systems like bacteria and yeast. The increasing demand in antibody based methodologies is driving advances in the production and purification of genetically engineered antibodies and antibody fragments. While advances in expression systems allow the production of high titers of antibodies, there exist some limits imposed by the downstream methodologies which are not efficient enough to ensure their industrialization.The main aim of this review is to highlight the principal characteristics of single-chain variable fragments of antibodies addressing advances and perspectives on scFv purification.     

Detection of Leishmania infantum in animals and their ectoparasites by conventional PCR and real time PCR

Visceral leishmaniosis (VL) is a parasitic disease caused by Leishmania infantum, which is primarily transmitted by phlebotomine sandflies. However, there has been much speculation on the role of other arthropods in the transmission of VL. Thus, the aim of this study was to assess the presence of L. infantum in cats, dogs and their ectoparasites in a VL-endemic area in northeastern Brazil. DNA was extracted from blood samples and ectoparasites, tested by conventional PCR (cPCR) and quantitative real time PCR (qPCR) targeting the L. infantum kinetoplast DNA. A total of 280 blood samples (from five cats and 275 dogs) and 117 ectoparasites from dogs were collected. Animals were apparently healthy and not previously tested by serological or molecular diagnostic methods. Overall, 213 (76.1 %) animals and 51 (43.6 %) ectoparasites were positive to L. infantum, with mean parasite loads of 795.2, 31.9 and 9.1 fg in dogs, cats and ectoparasites, respectively. Concerning the positivity between dogs and their ectoparasites, 32 (15.3 %) positive dogs were parasitized by positive ectoparasites. The overall concordance between the PCR protocols used was 59.2 %, with qPCR being more efficient than cPCR; 34.1 % of all positive samples were exclusively positive by qPCR. The high number of positive animals and ectoparasites also indicates that they could serve as sentinels or indicators of the circulation of L. infantum in risk areas.     

Separation of inulinase from Kluyveromyces marxianus using reversed micellar extraction

Inulinase from K. marxianus was extracted into a reversed micelle phase of the cationic surfactant BDBAC (n-benzyl-n-dodecyl-n-bis(2-hydroxyethyl)ammonium chloride) in isooctane/hexanol. The extractions carried out with cells (5.9 g/l) presented a recovery yield of 87% and a purification factor 2.8. Similar values were found for inulinase recovered from the clarified medium (91% recovery yield and 2.8 purification factor). For scaled-up (400-fold) extractions, the recovery of the initial activity reached 77% and the enrichment factor was 2.8.     

Bromelain purification through unconventional aqueous two-phase system (PEG/ammonium sulphate)

This paper focuses on the feasibility of unconventional aqueous two-phase systems for bromelain purification from pineapple processing waste. The main difference in comparison with conventional systems is the integration of the liquid–liquid extraction technique with fractional precipitation, which can decrease the protein content with no loss of biological activity by removing of unwanted molecules. The analysis of the results was based on the response surface methodology and revealed that the use of the desirability optimisation methodology (DOM) was necessary to achieve higher purification factor values and greater bromelain recovery. The use of DOM yielded an 11.80-fold purification factor and 66.38 % biological activity recovery using poly(ethylene glycol) (PEG) with a molar mass of 4,000, 10.86 % PEG concentration (m/m) and 36.21 % saturation of ammonium sulphate.     

The antitumoral, trypanocidal and antileishmanial activities of extract and alkaloids isolated from Duguetia furfuracea

The alkaloid extract and five alkaloids isolated from subterranean stem bark of Duguetia furfuracea (Annonaceae) were investigated for the following activities: antitumoral, trypanocidal and leishmanicidal. Dicentrinone showed weak cytotoxicity, but it had the strongest leishmanicidal activity (IC₅₀ 0.01 μM). Duguetine and duguetine β-N-oxide caused considerable antitumoral activity in every cell lines evaluated, although duguetine was more active against trypomastigote forms (IC₅₀ 9.32 μM) than other alkaloids tested.     

Learning brain dynamics for decoding and predicting individual differences

Insights from functional Magnetic Resonance Imaging (fMRI), as well as recordings of large numbers of neurons, reveal that many cognitive, emotional, and motor functions depend on the multivariate interactions of brain signals. To decode brain dynamics, we propose an architecture based on recurrent neural networks to uncover distributed spatiotemporal signatures. We demonstrate the potential of the approach using human fMRI data during movie-watching data and a continuous experimental paradigm. The model was able to learn spatiotemporal patterns that supported 15-way movie-clip classification (∼90%) at the level of brain regions, and binary classification of experimental conditions (∼60%) at the level of voxels. The model was also able to learn individual differences in measures of fluid intelligence and verbal IQ at levels comparable to that of existing techniques. We propose a dimensionality reduction approach that uncovers low-dimensional trajectories and captures essential informational (i.e., classification related) properties of brain dynamics. Finally, saliency maps and lesion analysis were employed to characterize brain-region/voxel importance, and uncovered how dynamic but consistent changes in fMRI activation influenced decoding performance. When applied at the level of voxels, our framework implements a dynamic version of multivariate pattern analysis. Our approach provides a framework for visualizing, analyzing, and discovering dynamic spatially distributed brain representations during naturalistic conditions.