Ceftriaxone Attenuated Anxiety-Like Behavior and Enhanced Brain Glutamate Transport in Zebrafish Subjected to Alcohol Withdrawal

Neurochemical Research - Chronic and/or excessive consumption of alcohol followed by reduced consumption or abstention can result in Alcohol Withdrawal Syndrome. A number of behavioral changes and...     

Jaburetox,a urease-derived peptide: Effects on enzymatic pathways of the cockroach Nauphoeta cinerea

Jaburetox is a recombinant peptide derived from one of the Canavalia ensiformis urease isoforms. This peptide induces several toxic effects on insects of different orders, including interference on muscle contractility in cockroaches, modulation of UDP-N-acetylglucosamine pyrophosphorylase (UAP) and nitric oxide synthase (NOS) activities in the central nervous system of triatomines, as well as activation of the immune system in Rhodnius prolixus. When injected, the peptide is lethal for R. prolixus and Triatoma infestans. Here, we evaluated Jaburetox toxicity to Nauphoeta cinerea cockroaches, exploring the effects on the central nervous system through the activities of UAP, NOS, acid phosphatases (ACP), and acetylcholinesterase (AChE). The results indicated that N. cinerea is not susceptible to the lethal effect of the peptide. Moreover, both in vivo and in vitro treatments with Jaburetox inhibited NOS activity, without modifying the protein levels. No alterations on ACP activity were observed. In addition, the enzyme activity of UAP only had its activity affected at 18 hr after injection. The peptide increased the AChE activity, suggesting a mechanism involved in overcoming the toxic effects. In conclusion, our findings indicate that Jaburetox affects the nitrinergic signaling as well as the AChE and UAP activities and establishes N. cinerea as a Jaburetox-resistant model for future comparative studies.     

Exploring the potential of nuclear and mitochondrial sequencing data generated through genome‐skimming for plant phylogenetics: A case study from a clade of neotropical lianas

Few botanical studies have explored the potential of nuclear ribosomal DNA (nrDNA) and mitochondrial DNA (mtDNA) data obtained through genome skimming for phylogeny reconstruction. Here, we analyzed the phylogenetic information included in the nrDNA and mtDNA of 44 species of the “Adenocalymma‐Neojobertia” clade (Bignoniaceae). To deal with intraindividual polymorphisms within the nrDNA, different coding schemes were explored through the analyses of four datasets: (i) “nrDNA contig,” with base call following the majority rule; (ii) “nrDNA ambiguous,” with ambiguous base calls; (iii) “nrDNA informative,” with ambiguities converted to multistate characters; and, (iv) “mitochondrial,” with 39 mitochondrial genes. Combined analyses using the nrDNA and mtDNA data and previously published “plastid” datasets were also conducted. Trees were obtained using Maximum Likelihood and Bayesian criteria. The congruence among genomes was assessed. The nrDNA datasets were shown to be highly polymorphic within individuals, while the “mitochondrial” dataset was the least informative, with 0.36% of informative bases within the ingroup. The topologies inferred using the nrDNA and mtDNA datasets were broadly congruent with the tree derived from the analyses of the “plastid” dataset. The topological differences recovered were generally poorly supported. The topology that resulted from the analyses of the “combined” dataset largely resembles the “plastid” tree. These results highlight limitations of nuclear ribosomal DNA and mitochondrial genes for phylogeny reconstruction obtained through genome skimming and the need to include more data from both genomes. The different topologies observed among genomes also highlight the importance of exploring data from various genomes in plant phylogenetics.     

Natriuretic peptide system: a link between fat mass and cardiac hypertrophy and hypertension in fat-fed female rats

The present study was designed to develop an animal model of hypertension and cardiac hypertrophy associated with obesity in female rats. Furthermore, we studied the involvement of the natriuretic peptide system in the mechanisms of these conditions. Obesity was induced in Wistar rats by a high fat diet and ovariectomy. The rats were divided into four groups: ovariectomized or sham-operated with high-fat diet and ovariectomized or sham-operated with control diet. After 24 weeks of diet, rats were killed, and their tissues were removed. Cardiac atrial natriuretic peptide (ANP), clearance receptor (NPr-C) gene expression was determined by PCR. ANP concentrations were measured in plasma. Ovariectomized fat-fed rats (OF) showed increased body weight, visceral fat depot and blood pressure and decreased sodium excretion compared to other groups. Also, these rats showed higher heart-to-body weight and cell diameters of ventricular cardiomyocytes and lower cardiac ANP mRNA and plasma ANP than the control group. The adipocyte and renal NPr-C mRNA of OF rats were higher than the control group. These data showed that combined ovariectomy and high fat diet elicited obesity, hypertension and cardiac hypertrophy. These results suggest that the impairment of the natriuretic peptide system may be one of the mechanisms involved not only in development of hypertension but also in cardiac hypertrophy associated with obesity in ovariectomized rats.     

Role of <Emphasis Type="Italic">Trypanosoma cruzi</Emphasis> peroxiredoxins in mitochondrial bioenergetics

Trypanosoma cruzi cytosolic (TcCPx) and mitochondrial tryparedoxin peroxidase (TcMPx) play a fundamental role in H₂O₂ detoxification. Herein, mitochondrial bioenergetics was evaluated in cells that overexpressed TcCPx (CPx) and TcMPx (MPx) and in pTEX. In MPx, a higher expression was observed for TcCPx, and the same correlation was true for CPx. Differences in H₂O₂ release among the overexpressing cells were detected when the mitochondrial respiratory chain was inhibited using antimycin A or thenoyltrifluoroacetone. MPx had higher O₂ consumption rates than pTEX and CPx, especially in the presence of oligomycin. In all of the cells, the mitochondrial membrane potential and the ATP levels were similar. Because of the mild uncoupling that was observed in MPx, the presence or induction of a proton transporter in the mitochondrial membrane is suggested when TcMPx is expressed at higher levels. Our results show a possible interplay between the cytosolic and mitochondrial antioxidant systems in a trypanosomatid.     

Construction and validation of two metagenomic DNA libraries from Cerrado soil with high clay content

A challenge of metagenomic studies is in the extraction and purification of DNA from environmental samples. The soils of the Cerrado region of Brazil present several technical difficulties to DNA extraction: high clay content (>55% w/w), low pH (4.7) and high iron levels (146 ppm). Here we describe for the first time the efficient recovery and purification of microbial DNA associated with these unusual soil characteristics and the construction and validation of two metagenomic libraries: a 150,000 clones library with insert size of approximately 8 kb and a 65,000 clones library with insert size of approximately 35 kb. The construction of these metagenomic libraries will allow the biotechnological exploitation of the microbial community present in the soil from this endangered biome.     

Hemoglobin Regeneration Efficiency in Anemic Rats: Effects on Bone Mineral Composition and Biomechanical Properties

This study reports the effects of dietary iron (Fe) deficiency and recovery on bone mineral composition and strength in anemic rats submitted to a hemoglobin (Hb) repletion assay. Weanling male Wistar rats were fed a low-Fe diet (12 mg/kg) for 15 days followed by 2 weeks of Fe repletion with diets providing 35 mg Fe/kg as either ferrous sulfate (n = 8) or ferric pyrophosphate (FP; n = 12). At final day of each period (depletion and repletion), Fe-adequate animals were also euthanized. Iron status (blood Hb, Hb Fe pool, Hb regeneration efficiency), tibia mineral concentrations (Ca, Mg, Fe, Cu, and Zn) and biomechanical properties were evaluated. Iron-deficient rats had lower tibia Fe and Mg levels and bone strength when compared to controls. Yield load and resilience were positively related to tibia Mg levels (r = 0.47, P = 0.02 and r = 0.56, P = 0.004, respectively). Iron repletion did not recover tibia Mg concentrations impaired by Fe deficiency. Moreover, bone elastic properties were negatively affected by FP consumption. In conclusion, bone mineral composition and strength were affected by Fe deficiency, whereas dietary Fe source influenced tibia Mg and resistance in the period during which rats were recovering from anemia.     

DNA strand breakage induced by CuII and NiII, in the presence of peptide models of histone H2B

In the present study we used the plasmid relaxation assay, a very sensitive method for detection of DNA strand breaks in vitro, in order to evaluate the role of peptide fragments of histone H2B in DNA strand breakage induced by copper and nickel. We have found that in the presence of peptides modeling the histone fold domain (H2B_32-62 and H2B_63-93) as well as the N-terminal tail (H2B_1-31) of histone H2B there is an increased DNA damage by Cu²⁺/H₂O₂ and Ni²⁺/H₂O₂ reaction mixtures. On the contrary, the C-terminal tail (H2B_94-125) seems to have a protective role on the attack of ROS species to DNA. We have rendered our findings to the interactions of the peptides with DNA, as well as with the metal.