Antidepressant effect of taurine in diabetic rats

Clinical and preclinical studies have shown that diabetic individuals present more depressive behaviors than non-diabetic individuals. Taurine, one of the most abundant free amino acids in the central nervous system, modulates a variety of biological functions and acts as an agonist at GABA_A receptors. Our objective was to assess the antidepressant effect of taurine in diabetic rats. Additionally, we studied the effect of taurine on weight gain, water and food intake, and blood glucose levels in diabetic and non-diabetic rats. Male Wistar rats were divided into control (CTR) and streptozotocin-induced diabetic (STZ) groups and were administered daily 0, 25, 50 or 100?mg/kg of taurine (n?=?10 per subgroup) intraperitoneally. After 28?days of treatment, the animals were exposed to the forced swimming test, and their behaviors were recorded. Weight gain, water and food intake, and blood glucose levels were measured weekly. Our results showed that STZ rats had a higher immobility duration than CTR rats, and taurine decreased this depressive-like behavior in STZ rats at doses of 25 and 100?mg/kg. Both of these doses of taurine also decreased water intake and improved weight gain in STZ rats. All doses of taurine decreased the water intake in CTR rats. Taurine, at a dose of 100?mg/kg, decreased food intake and blood glucose levels in STZ rats. Because taurine is a GABA agonist and both amino acids are lower in the plasma of diabetic and depressive individuals, we hypothesize that taurine may represent a new adjuvant drug for the treatment of depression in diabetic individuals.     

Lipid transfer proteins in coffee: isolation of Coffea orthologs,Coffea arabica homeologs,expression during coffee fruit development and promoter analysis in transgenic tobacco plants

The aim of the present study was to perform a genomic analysis of non-specific lipid-transfer proteins (nsLTPs) in coffee. Several nsLTPs-encoding cDNA and gene sequences were cloned from Coffea arabica and Coffea canephora species. In this work, their analyses revealed that coffee nsLTPs belong to Type II LTP characterized under their mature forms by a molecular weight of around 7.3 kDa, a basic isoelectric points of 8.5 and the presence of typical CXC pattern, with X being an hydrophobic residue facing towards the hydrophobic cavity. Even if several single nucleotide polymorphisms were identified in these nsLTP-coding sequences, 3D predictions showed that they do not have a significant impact on protein functions. Northern blot and RT-qPCR experiments revealed specific expression of Type II nsLTPs-encoding genes in coffee fruits, mainly during the early development of endosperm of both C. arabica and C. canephora. As part of our search for tissue-specific promoters in coffee, an nsLTP promoter region of around 1.2 kb was isolated. It contained several DNA repeats including boxes identified as essential for grain specific expression in other plants. The whole fragment, and a series of 5′ deletions, were fused to the reporter gene β-glucuronidase (uidA) and analyzed in transgenic Nicotiana tabacum plants. Histochemical and fluorimetric GUS assays showed that the shorter (345 bp) and medium (827 bp) fragments of nsLTP promoter function as grain-specific promoters in transgenic tobacco plants.     

Phenotypic plasticity to light of two congeneric trees from contrasting habitats: Brazilian Atlantic Forest versus cerrado (savanna)

The Brazilian Atlantic Forest is a typically multi-layer tropical forest, while cerrado (savanna) is a patchy habitat with different physiognomy. Despite these differences, both habitats have high light heterogeneity. Functional traits of Dalbergia nigra and D. miscolobium from the Atlantic Forest and cerrado, respectively, were evaluated under shade (25% of full sunlight) and full sunlight in a nursery experiment. We hypothesised that both species should benefit from high phenotypic plasticity in relation to light. Plasticity was estimated using the relative distance phenotypic index (RDPI). D. miscolobium had lower shoot growth under both light conditions, suggesting it has low competitive capacity in the forest environment, which could explain its limited ability to expand over areas of Atlantic Forest. The studied species exhibited photoprotection strategies under high light and improved light capture under low light. Stomatal conductance, ETR(max) (maximum electron transport rate), PPFD(sat) (saturating photosynthetically active photon flux density), chlorophyll and carotenoid content had higher RDPI than stem morphological traits. Although both species showed considerable phenotypic plasticity, D. miscolobium had higher RDPI for eight of 11 evaluated traits. This high plasticity could be one of the factors that explain the occurrence of this species in a wide range of environmental conditions, from open grassland to dense woodlands, and it could also reflect its adaptation to high light. D. nigra also had considerable plasticity and good growth performance in both shade and full sunlight, but its absence in areas of cerrado suggests that factors other than light limit its occurrence in these habitats.     

Non-redox-active small-molecules can accelerate oxidative protein folding by novel mechanisms

Multi-disulfide-bond-containing proteins acquire their native structures through an oxidative folding reaction which involves formation of native disulfide bonds through thiol-disulfide exchange reactions between cysteines and disulfides coupled to a conformational folding event. Oxidative folding rates of the four-disulfide-bond-containing protein bovine pancreatic ribonuclease A (RNase A) in the presence of the synthetic redox-active molecule, (+/-)-trans-1,2-bis(2-mercaptoacetamido)cyclohexane (BMC), and in combination with non-redox-active trimethylamine-N-oxide (TMAO), and trifluorethanol were determined by HPLC analysis. The data indicate that regeneration of RNase A is enhanced 2-fold by BMC (50 microM) and 3-fold upon addition of TMAO (0.2 M) and TFE (3% v/v) relative to control experiments performed in the absence of small-molecules. Examination of the native tendency of the fully-reduced polypeptide and the stability of key folding intermediates suggests that the increased oxidative folding rate can be attributed to native-like elements induced within the fully-reduced polypeptide and the stabilization of native-like species by added non-redox-active molecules.     

Protective effects of acerola juice on genotoxicity induced by iron in vivo

Metal ions such as iron can induce DNA damage by inducing reactive oxygen species (ROS) and oxidative stress. Vitamin C is one of the most widely consumed antioxidants worldwide, present in many fruits and vegetables, especially inMalpighia glabra L., popularly known as acerola, native to Brazil. Acerola is considered a functional fruit due to its high antioxidant properties and phenolic contents, and therefore is consumed to prevent diseases or as adjuvant in treatment strategies. Here, the influence of ripe and unripe acerola juices on iron genotoxicity was analyzed in vivo using the comet assay and micronucleus test. The comet assay results showed that acerola juice exerted no genotoxic or antigenotoxic activity. Neither ripe nor unripe acerola juices were mutagenic to animals treated with juices, in micronucleus test. However, when compared to iron group, the pre-treatment with acerola juices exerted antimutagenic activity, decreasing significantly micronucleus mean values in bone marrow. Stage of ripeness did not influence the interaction of acerola compounds with DNA, and both ripe and unripe acerola juices exerted protective effect over DNA damage generated by iron.     

Production and Regeneration of Thiobacillus ferrooxidans Spheroplasts

We have isolated a metabolite of territrem, designated territrem B', from the chloroform extract of a rice culture of Aspergillus terreus 23-1 by using the same isolation procedure as that for territrems A, B, and C. The present isolation procedure gave about 10 mg of territrem B' from 4 kg of rice culture per batch. Analysis of the high-resolution mass spectrum showed that the molecular composition of territrem B' is C29H34O10 (found, 542.2167; required, 542.200). Some results of physicochemical and acute tests are presented in this paper. Single-crystal X-ray diffractometry of territrem B' indicated that the three-dimensional structure of territrem B' has not changed significantly from that of territrem B except for the insertion of one oxygen atom into territrem B to make an additional pyron ring in the E ring. The tremorgenic activity of territrem B' is greatly reduced as tested by intraperitoneal injection in mice.     

Cholesterol trafficking and raft-like membrane domain composition mediate scavenger receptor class B type 1-dependent lipid sensing in intestinal epithelial cells

Scavenger receptor Class B type 1 (SR-B1) is a lipid transporter and sensor. In intestinal epithelial cells, SR-B1-dependent lipid sensing is associated with SR-B1 recruitment in raft-like/ detergent-resistant membrane domains and interaction of its C-terminal transmembrane domain with plasma membrane cholesterol. To clarify the initiating events occurring during lipid sensing by SR-B1, we analyzed cholesterol trafficking and raft-like domain composition in intestinal epithelial cells expressing wild-type SR-B1 or the mutated form SR-B1-Q445A, defective in membrane cholesterol binding and signal initiation. These features of SR-B1 were found to influence both apical cholesterol efflux and intracellular cholesterol trafficking from plasma membrane to lipid droplets, and the lipid composition of raft-like domains. Lipidomic analysis revealed likely participation of d18:0/16:0 sphingomyelin and 16:0/0:0 lysophosphatidylethanolamine in lipid sensing by SR-B1. Proteomic analysis identified proteins, whose abundance changed in raft-like domains during lipid sensing, and these included molecules linked to lipid raft dynamics and signal transduction. These findings provide new insights into the role of SR-B1 in cellular cholesterol homeostasis and suggest molecular links between SR-B1-dependent lipid sensing and cell cholesterol and lipid droplet dynamics.     

Presence of fimH,mrkD, and irp2 Virulence Genes in KPC-2-Producing Klebsiella pneumoniae Isolates in Recife-PE,Brazil

Klebsiella pneumoniae strains can produce different virulence factors, such as fimbrial adhesins and siderophores, which are important in the colonization and development of the infection. The aims of this study were to determine the occurrence of fimH, mrkD, and irp2 virulence genes in 22 KPC-2-producing K. pneumoniae isolates as well as 22 not producing-KPC isolates, from patients from different hospitals in Recife-PE, Brazil, and also to analyze the clonal relationship of the isolates by enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR). The genes were detected by PCR and DNA sequencing. The bla _KPC-2 gene was identified in 22 KPC-positive isolates. On analyzing the antimicrobial susceptibility profile of the isolates, it was detected that polymyxin and amikacin were the antimicrobials of best activity against K. pneumoniae. On the other hand, five isolates exhibited resistance to polymyxin. In the KPC-positive group, was observed a high rate of resistance to cephalosporins, followed by carbapenems. Molecular typing by ERIC-PCR detected 38 genetic profiles, demonstrating a multiclonal spread of the isolates analyzed. It was observed that the virulence genes irp2, mrkD, and fimH were seen to have together a higher frequency in the KPC-positive group. The accumulation of virulence genes of KPC-positive K. pneumoniae isolates, observed in this study, along with the multi-resistance impose significant therapeutic limitations on the treatment of infections caused by K. pneumoniae.