Malnutrition enhances cardiovascular responses to chemoreflex activation in awake rats

Several studies in the literature suggest that low-protein intake is associated with increases in sympathetic efferent activity and cardiovascular disease. Among the possible mechanisms, changes in the neurotransmission of cardiovascular reflexes have been implicated. Therefore, the present study comprised the evaluation of chemoreflex responsiveness in rats subjected to a low-protein diet during the 35 days after weaning. As a result, we observed that malnourished rats presented higher levels of baseline mean arterial pressure and heart rate and exhibited a mild increase in the pressor response to chemoreflex activation. They also exhibited a massive bradycardic response to chemoreflex activation. Interestingly, bilateral ligature of the carotid body arteries further increased baseline mean arterial pressure and heart rate in malnourished animals. The data suggest severe autonomic imbalance and/or change in the central interplay between neural and cardiovascular mechanisms.     

Synthesis and in vitro anti Mycobacterium tuberculosis activity of a series of phthalimide derivatives

New phthalimide derivatives were easily prepared through condensation of phthalic anhydride and selected amines with variable yields (70–90%). All compounds (3a–l) were evaluated against Mycobacterium tuberculosis H₃₇Rv using Alamar Blue susceptibility. The compounds 3c, 3i, and 3l have the minimum inhibitory concentrations (MICs) of 3.9, 7.8, and 5.0 μg/mL, respectively, and could be considered new lead compounds in the treatment of tuberculosis and multi-drug resistant tuberculosis.     

Biologic data of Macaca mulatta, Macaca fascicularis, and Saimiri sciureus used for research at the Fiocruz primate center

Physiological parameters of laboratory animals used for biomedical research is crucial for following several experimental procedures. With the intent to establish baseline biologic parameters for non-human primates held in closed colonies, hematological and morphometric data of captive monkeys were determined. Data of clinically healthy rhesus macaques (Macaca mulatta), cynomolgus monkeys (Macaca fascicularis), and squirrel monkeys (Saimiri sciureus) were collected over a period of five years. Animals were separated according to sex and divided into five age groups. Hematological data were compared with those in the literature by Student's t test. Discrepancies with significance levels of 0.1, 1 or 5% were found in the hematological studies. Growth curves showed that the sexual dimorphism of rhesus monkeys appeared at an age of four years. In earlier ages, the differences between sexes could not be distinguished (p < 0.05). Sexual dimorphism in both squirrel monkeys and cynomolgus monkeys occurred at an age of about 32 months. Data presented in this paper could be useful for comparative studies using primates under similar conditions.     

Combined submerged and solid substrate fermentation for the bioconversion of lignocellulose

A novel two-stage bioreactor has been designed for a combined submerged (SF) and solid substrate fermentation (SSF) of wheat straw. The straw was pretreated with steam, and cellulases from the culture fluid of Trichoderma reesei were adsorbed on it for increased bioconvertibility. SSF was conducted in the top part of the bioreactor by inoculating the straw with a 36-h mycelial culture of T. reesei, or Coriolus versicolor. In the bottom part of the fermenter, Endomycopsis fibuliger was grown in SF. The SF liquor was recirculated through the SSF stage at 24 h intervals to remove glucose and other metabolites that may inhibit growth, and to maintain optimum moisture level and temperature. The removed glucose and other metabolites provided nutrients for the yeast in the SF stage. The combined fermentation resulted in overall higher biomass yield, increased bioconversion, increased cellulase production, and increased digestibility compared with single SSF or SF.     

Characterization of Clostridium thermocellum Isolates Grown on Cellulose and Sugarcane Bagasse

Although plant cell walls may be degraded by microbial free enzymes, many bacteria degrade cellulose via enzyme complexes called cellulosomes. The study of the structures and mechanisms of these large macromolecular complexes is an active and ongoing research topic, with the goal of developing methods to improve lignocellulosic biomass conversion using cellulosomes. The aim of the present work was to evaluate and characterize the holocellulolytic activities produced by two new isolates (ISO1 and ISO2) of the spore-forming thermophilic anaerobic bacterium Clostridium thermocellum, during growth on crystalline cellulose and sugarcane bagasse, in comparison with activities obtained from the C. thermocellum strain CthJW. The pH and temperature values for optimal growth of the isolates were pH 7 and 60 °C, respectively. The isolates produced cellulolytic, xylanolytic, and pectinolytic activities when cultured on crystalline cellulose or sugarcane bagasse, which have never been used previously as the sole carbon source for these bacteria. The profiles of secreted proteins for these isolates, ISO1 and ISO2, were quite different from those obtained for the standard strain CthJW and from each other, as shown by 2D gel electrophoresis maps, and these profiles also depend on the carbon source used. Different protein isoforms were also detected in the maps for all growth conditions and bacterial strains. MALDI-TOF mass spectrometry was used to identify the differentially expressed proteins for ISO1 and ISO2 under growth in the presence of cellulose as carbon source. Twenty-five differentially expressed spots were identified and grouped into 8 functional categories: metabolism (20 %), motor function (20 %), protein synthesis (12 %), oxidative stress (16 %), secretory pathway (12 %), cellulose hydrolysis (4 %), protein folding (4 %), and defense (12 %). Spots 200 and 197, identified as a glycosyl hydrolase family member 9 and as a chaperone GroEL, respectively, were detected for all isolates and are potentially related to cellulosome architecture.     

The Cytotoxic and Proapoptotic Activities of Hypnophilin are Associated with Calcium Signaling in UACC‐62 Cells

Hypnophilin (HNP) is a sesquiterpene that is isolated from Lentinus cf. strigosus and has cytotoxic activities. Here, we studied the calcium signaling and cytotoxic effects of HNP in UACC‐62 cells, a human skin melanoma cell line. HNP was able to increase the intracellular calcium concentration in UACC‐62 cells, which was blocked in cells stimulated in Ca²⁺‐free media. HNP treatment with BAPTA‐AM, an intracellular Ca²⁺ chelator, caused an increase in calcium signals. HNP showed cytotoxicity against UACC‐62 cells in which it induced DNA fragmentation and morphological alterations, including changes in the nuclear chromatin profile and increased cytoplasmatic vacuolization, but it had no effect on the plasma membrane integrity. These data suggest that cytotoxicity in UACC‐62 cells, after treatment with HNP, is associated with Ca²⁺ influx. Together, these findings suggest that HNP is a relevant tool for the further investigation of new anticancer approaches. © 2013 Wiley Periodicals, Inc. J BiochemMol Toxicol 27:479‐485, 2013; View this article online at wileyonlinelibrary.com . DOI 10.1002/jbt.21507     

Antiplasmodial activity study of angiotensin II via Ala scan analogs

Angiotensin II (AII) as well as analog peptides shows antimalarial activity against Plasmodium gallinaceum and Plasmodium falciparum, but the exact mechanism of action is still unknown. This work presents the solid‐phase synthesis and characterization of eight peptides corresponding to the alanine scanning series of AII plus the amide‐capped derivative and the evaluation of the antiplasmodial activity of these peptides against mature P. gallinaceum sporozoites. The Ala screening data indicates that the replacement of either the Ile⁵ or the His⁶ residues causes minor effects on the in vitro antiplasmodial activity compared with AII, i.e. AII (88%), [Ala⁶]‐AII (79%), and [Ala⁵]‐AII (75%). Analogs [Ala³]‐AII, [Ala¹]‐AII, and AII‐NH₂ showed antiplasmodial activity around 65%, whereas the activity of the [Ala⁸]‐AII, [Ala⁷]‐AII, [Ala⁴]‐AII, and [Ala²]‐AII analogs is lower than 45%. Circular dichroism data suggest that AII and the most active analogs adopt a β‐fold conformation in different solutions. All AII analogs, except [Ala⁴]‐AII and [Ala⁸]‐AII, show contractile responses and interact with the AT₁ receptor, [Ala⁵]‐AII and [Ala⁶]‐AII. In conclusion, this approach is helpful to understand the contribution of each amino acid residue to the bioactivity of AII, opening new perspectives toward the design of new sporozoiticidal compounds. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.     

In Silico,In Vitro and In Vivo Toxicological Assessment of BPP-BrachyNH<Subscript>2</Subscript>, A Vasoactive Proline-Rich Oligopeptide from <Emphasis Type="Italic">Brachycephalus ephippium</Emphasis>

BPP-BrachyNH₂ is a proline-rich oligopeptide (PRO) firstly identified in skin secretion of the frog Brachycephalus ephippium, which possess in vitro inhibitory activity of angiotensin-I converting enzyme (ACE) and endothelium-dependent vasorelaxant activity. Considering its potential application in the treatment of cardiovascular diseases, the present work assessed the toxicological profile of the BPP-BrachyNH₂. The in silico toxicity prediction was performed from the best model obtained through the optimization of the FASTA query peptide. This prediction study revealed that BPP-BrachyNH₂ induced high predicted LD₅₀ values for both humans and rats, and then is well-tolerated in the recommended range. The MTT assay was applied for the in vitro cytotoxic evaluation in murine macrophages. In this assay, a decrease of cell viability was not observed. The in vivo acute toxicological study was performed after the intraperitoneal administration of BPP-BrachyNH₂ at doses of 5 and 50 mg/kg. After intraperitoneal administration, no death, alterations in behavioral parameters or weight gain curve was observed, as well as none in the serum biochemical parameters, and gross pathological and histopathological analyses. These observations demonstrates an acceptable safety profile for BPP-BrachyNH₂, leading towards further studies focused on investigation of pharmacological and therapeutical applications for this peptide.