Structural characterization of the cell wall D-glucans isolated from the mycelium of Botryosphaeria rhodina MAMB-05

Three D-glucans were isolated from the mycelium of the fungus Botryosphaeria rhodina MAMB-05 by sequential extraction with hot-water and hot aqueous KOH (2% w/v) followed by ethanol precipitation. Following their purification by gel permeation chromatography on Sepharose CL-4B, the structural characteristics of the D-glucans were determined by FT-IR and 13C NMR spectroscopy and, after methylation, by GC-MS. The hot-water extract produced a fraction designated Q1A that was a beta-(1-->6)-D-glucan with the following structure: [Formula: see text] The alkaline extract, when subjected to repeated freeze-thawing, yielded two fractions: K1P (insoluble) that comprised a beta-(1-->3)-D-glucan with beta-D-glucose branches at C-6 with the structure: [Formula: see text] and K1SA (soluble) consisting of a backbone chain of alpha-(1-->4)-linked D-glucopyranosyl residues substituted at O-6 with alpha-D-glucopyranosyl residues: [Formula: see text]     

ZrFsy1, a High-Affinity Fructose/H+ Symporter from Fructophilic Yeast Zygosaccharomyces rouxii

Zygosaccharomyces rouxii is a fructophilic yeast than can grow at very high sugar concentrations. We have identified an ORF encoding a putative fructose/H⁺ symporter in the Z. rouxii CBS 732 genome database. Heterologous expression of this ORF in a S. cerevisiae strain lacking its own hexose transporters (hxt-null) and subsequent kinetic characterization of its sugar transport activity showed it is a high-affinity low-capacity fructose/H⁺ symporter, with K_m 0.45±0.07 mM and V_max 0.57±0.02 mmol h⁻¹ (gdw) ⁻¹. We named it ZrFsy1. This protein also weakly transports xylitol and sorbose, but not glucose or other hexoses. The expression of ZrFSY1 in Z. rouxii is higher when the cells are cultivated at extremely low fructose concentrations (<0.2%) and on non-fermentable carbon sources such as mannitol and xylitol, where the cells have a prolonged lag phase, longer duplication times and change their microscopic morphology. A clear phenotype was determined for the first time for the deletion of a fructose/H⁺ symporter in the genome where it occurs naturally. The effect of the deletion of ZrFSY1 in Z. rouxii cells is only evident when the cells are cultivated at very low fructose concentrations, when the ZrFsy1 fructose symporter is the main active fructose transporter system.     

Vinpocetine attenuates the metabolic dysfunction induced by amyloid β-peptides in PC12 cells

The cytoprotective effect of vinpocetine [14-ethoxycarbonyl-(3α,16α-ethyl)-14,15-eburnamine] was investigated on PC12 cells treated with the amyloid β-peptides (Aβ) for 24 hours. Vinpocetine was shown to protect cells from the inhibition in redox status induced by exposure to Aβ_25–35 and Aβ_1–40, the maximal protection being achieved at a vinpocetine concentration of 40 μM. At this concentration, vinpocetine blocked the inhibition of the mitochondrial respiratory chain complexes II–III and IV and completely abolished the depletion of pyruvate levels induced by toxic concentrations of Aβ peptides. Furthermore, the accumulation of ROS in cells exposed to Aβ_25–35 and Aβ_1–40 evaluated using the fluorescent probe 2′,7′-dichlorofluorescin (DCF), was reduced in the presence of 40 μM vinpocetine. Taken together, the data presented herein demonstrate that vinpocetine protects cells from Aβ toxicity, preventing the generation of oxidative stress due to the excessive accumulation of ROS. This study suggests that vinpocetine can exert neuroprotective properties which might be of importance and contribute to its clinical efficacy in the treatment of Alzheimer's disease or other neurodegenerative disorders in which oxidative stress is involved.     

Glucose-dependent expansion of pancreatic beta-cells by the protein p8 in vitro and in vivo

p8 protein expression is known to be upregulated in the exocrine pancreas during acute pancreatitis. Own previous work revealed glucose-dependent p8 expression also in endocrine pancreatic beta-cells. Here we demonstrate that glucose-induced INS-1 beta-cell expansion is preceded by p8 protein expression. Moreover, isopropylthiogalactoside (IPTG)-induced p8 overexpression in INS-1 beta-cells (p8-INS-1) enhances cell proliferation and expansion in the presence of glucose only. Although beta-cell-related gene expression (PDX-1, proinsulin I, GLUT2, glucokinase, amylin) and function (insulin content and secretion) are slightly reduced during p8 overexpression, removal of IPTG reverses beta-cell function within 24 h to normal levels. In addition, insulin secretion of p8-INS-1 beta-cells in response to 0-25 mM glucose is not altered by preceding p8-induced beta-cell expansion. Adenovirally transduced p8 overexpression in primary human pancreatic islets increases proliferation, expansion, and cumulative insulin secretion in vitro. Transplantation of mock-transduced control islets under the kidney capsule of immunosuppressed streptozotocin-diabetic mice reduces blood glucose and increases human C-peptide serum concentrations to stable levels after 3 days. In contrast, transplantation of equal numbers of p8-transduced islets results in a continuous decrease of blood glucose and increase of human C-peptide beyond 3 days, indicating p8-induced expansion of transplanted human beta-cells in vivo. This is underlined by a doubling of insulin content in kidneys containing p8-transduced islet grafts explanted on day 9. These results establish p8 as a novel molecular mediator of glucose-induced pancreatic beta-cell expansion in vitro and in vivo and support the notion of existing beta-cell replication in the adult organism.     

Clinical and cytokine profile evaluation in Northeast Brazilian psoriasis plaque-type patients

Objective and Design

Psoriasis is a common, enigmatic, and recurrent disease. The precise etiology and pathogenesis of psoriasis are still unclear. Psoriasis has been treated as an inflammatory disorder related to an underlying Th1/Th17-dominated immune response. Interleukins are involved in the development of psoriasis lesions through Th-17-associated inflammation. Th1 and Th17 cytokines are found in skin lesions and in the peripheral blood of psoriasis patients.We sought to analyze serum levels of IL-1-β, IL-8, IL-9, IL-27, IL-29, IL-35, IFN-γ, TNF and TGF-β in patients with psoriasis and healthy control volunteers.

Material

Blood samples were collected from fifty-three patients with psoriasis and thirty-five healthy controls.

Methods

Serum cytokines concentrations were determined using an enzyme-linked immunosorbent assay.

Results

Serum IL-8, IL-9, IL-27, IL-29 and TNF levels were statistically significant in psoriasis patients. Detectable serum IL-9 levels were found in 47 patients of the 53 in the psoriasis group.

Conclusions

Interleukins-8, 27, 29 and TNF levels measured in the serum of psoriasis patients were slightly elevated as compared to healthy controls in a weakly significant way. On the other hand, there were highly significant differences in IL-9 levels between the two groups.

     

Decolourisation of Remazol Brilliant Blue R via a novel Bjerkandera sp. strain

A novel strain of Bjerkandera sp. (B33/3), with particularly high decolourisation activities upon Poly R-478 and Remazol Brilliant Blue R (RBBR) dyes, was isolated. The role of the ligninolytic extracellular enzymes produced by this strain on decolourisation of RBBR was studied in some depth. The basis of decolourisation is an enzyme-mediated process, in which the main enzyme responsible is a recently described peroxidase with capacity for oxidation of manganese, as well as veratryl alcohol and 2,6-dimethoxyphenol in a manganese-independent reaction.     

Barefoot Plantar Pressure Indicates Progressive Neurological Damage in Patients with Human T-Cell Lymphotropic Virus Type 1 Infection

Background

The human T-Cell Lymphotropic Virus Type 1 (HTLV-1) is a retrovirus associated with neurological alterations; individuals with HTLV-1 infection may develop HTLV-1 associated myelopathy / tropical spastic paraparesis (HAM/TSP). Frequent neurological complaints include foot numbness and leg weakness. In this study, we compared the distribution of the body weight on different areas of the foot in HTLV-1 patients with HAM/TSP, asymptomatic HTLV-1 patients, and healthy individuals.

Methodology

We studied 36 HTLV-1 infected patients, who were divided in two groups of 18 patients each based on whether or not they had been diagnosed with HAM/TSP, and 17 control subjects. The evaluation included an interview on the patient’s clinical history and examinations of the patient’s reflexes, foot skin tactile sensitivity, and risk of falling. The pressure distribution on different areas of the foot was measured with baropodometry, using a pressure platform, while the patients had their eyes open or closed.

Main Findings

The prevalence of neurological disturbances—altered reflexes and skin tactile sensitivity and increased risk of falling—was higher in HTLV-1 HAM/TSP patients than in HTLV-1 asymptomatic patients. The medium and maximum pressure values were higher in the forefoot than in the midfoot and hindfoot in both HTLV-1 groups. In addition, the pressure on the hindfoot was lower in HAM/TSP patients compared to control subjects.

Conclusions

The neurological disturbances associated with HTLV-1 infection gradually worsened from HTLV-1 asymptomatic patients to HAM/TSP patients. Baropodometry is a valuable tool to establish the extent of neurological damage in patients suffering from HTLV-1 infection.     

Location,structure and behaviour of C-heterochromatin during meiosis in Dichroplus silveiraguidoi (Acrididae-Orthoptera)

The constitutive heterochromatin of Dichroplus silveiraguidoi, a species which shows an exceptionally low chromosome number (2n=8), was studied at meiosis with a staining technique on normal and hypotonically treated specimens. The results showed: 1) an unusual behaviour of the heterochromatic blocks located in the so-called synaptic region of the sex bivalent (Neo Y-Neo X), which remains paired from early prophase through metaphase I; 2) in normal or in hypotonically treated cells a heterogeneous configuration of the C-heterochromatic blocks was observed. This configuration is characterized by the existence of small positive granules interconnected by euchromatic filaments and is enhanced by treatment with a low ionic strength solution; 3) A weakly positive stained (intermediate) material was demonstrated in the Neo X chromosome; 4) A large amount of heterochromatin is distributed in the form of granular material along the length of the autosomes and as telomeric and centromeric blocks in all chromosomes. The possible evolutionary mechanisms involved and the significance of the C-band heterochromatin demonstrated in this species are discussed.