Graphene And Carbon Nanotube Nanocomposite For Gene Transfection.

Graphene and carbon nanotube nanocomposite (GCN) was synthesised and applied in gene transfection of pIRES plasmid conjugated with green fluorescent protein (GFP) in NIH-3T3 and NG97 cell lines. The tips of the multi-walled carbon nanotubes (MWCNTs) were exfoliated by oxygen plasma etching, which is also known to attach oxygen content groups on the MWCNT surfaces, changing their hydrophobicity. The nanocomposite was characterised by high resolution scanning electron microscopy; energy-dispersive X-ray, Fourier transform infrared and Raman spectroscopies, as well as zeta potential and particle size analyses using dynamic light scattering. BET adsorption isotherms showed the GCN to have an effective surface area of 38.5m(2)/g. The GCN and pIRES plasmid conjugated with the GFP gene, forming π-stacking when dispersed in water by magnetic stirring, resulting in a helical wrap. The measured zeta potential confirmed that the plasmid was connected to the nanocomposite. The NIH-3T3 and NG97 cell lines could phagocytize this wrap. The gene transfection was characterised by fluorescent protein produced in the cells and pictured by fluorescent microscopy. Before application, we studied GCN cell viability in NIH-3T3 and NG97 line cells using both MTT and Neutral Red uptake assays. Our results suggest that GCN has moderate stability behaviour as colloid solution and has great potential as a gene carrier agent in non-viral based therapy, with low cytotoxicity and good transfection efficiency.

All Green, But Equal? Morphological Traits And Ecological Implications On Spores Of Three Species Of Mosses In The Brazilian Atlantic Forest.

Spores of the tropical mosses Pyrrhobryum spiniforme, Neckeropsis undulata and N. disticha were characterized regarding size, number per capsule and viability. Chemical substances were analyzed for P. spiniforme and N. undulata spores. Length of sporophyte seta (spore dispersal ability) was analyzed for P. spiniforme. Four to six colonies per species in each site (lowland and highland areas of an Atlantic Forest; Serra do Mar State Park, Brazil) were visited for the collection of capsules (2008 - 2009). Neckeropsis undulata in the highland area produced the largest spores (ca. 19 µm) with the highest viability. The smallest spores were found in N. disticha in the lowland (ca. 13 µm). Pyrrhobryum spiniforme produced more spores per capsule in the highland (ca. 150,000) than in lowland (ca. 40,000); longer sporophytic setae in the lowland (ca. 64 mm) than in the highland (ca. 43 mm); and similar sized spores in both areas (ca. 16 µm). Spores of N. undulata and P. spiniforme contained lipids and proteins in the cytoplasm, and acid/neutral lipids and pectins in the wall. Lipid bodies were larger in N. undulata than in P. spiniforme. No starch was recorded for spores. Pyrrhobryum spiniforme in the highland area, different from lowland, was characterized by low reproductive effort, but presented many spores per capsule.

Reduced Lrp6 Expression And Increase In The Interaction Of Gsk3β With P53 Contribute To Podocyte Apoptosis In Diabetes Mellitus And Are Prevented By Green Tea.

In diabetes mellitus (DM), podocyte apoptosis leads to albuminuria and nephropathy progression. Low-density lipoprotein receptor-related protein 6 (LRP6) is WNT pathway receptor that is involved in podocyte death, adhesion and motility. Glycogen synthase kinase 3 (GSK3) interaction with p53 (GSK3-p53) promotes apoptosis in carcinoma cells. It is unknown if GSK3-p53 contributes to podocyte apoptosis in DM. In experimental DM, green tea (GT) reduces albuminuria by an unknown mechanism. In the present study, we assessed the role of the GSK3β-p53 in podocyte apoptosis and the effects of GT on these abnormalities. In diabetic spontaneously hypertensive rats (SHRs), GT prevents podocyte's p-LRP6 expression reduction, increased GSK3β-p53 and high p53 levels. In diabetic SHR rats, GT reduces podocyte apoptosis, foot process effacement and albuminuria. In immortalized mouse podocytes (iMPs), high glucose (HG), silencing RNA (siRNA) or blocking LRP6 (DKK-1) reduced p-LRP6 expression, leading to high GSK3β-p53, p53 expression, apoptosis and increased albumin influx. GSK3β blockade by BIO reduced GSK3β-p53 and podocyte apoptosis. In iMPs under HG, GT reduced apoptosis and the albumin influx by blocking GSK3β-p53 following the rise in p-LRP6 expression. These effects of GT were prevented by LRP6 siRNA or DKK-1. In conclusion, in DM, WNT inhibition, via LRP6, increases GSK3β-p53 and podocyte apoptosis. Maneuvers that inactivate GSK3β-p53, such as GT, may be renoprotective in DM.

Behaviour of oligodendrocytes and Schwann cells in an experimental model of toxic demyelination of the central nervous system

Oligodendrocytes and Schwann cells are engaged in myelin production, maintenance and repairing respectively in the central nervous system (CNS) and the peripheral nervous system (PNS). Whereas oligodendrocytes act only within the CNS, Schwann cells are able to invade the CNS in order to make new myelin sheaths around demyelinated axons. Both cells have some limitations in their activities, i.e. oligodendrocytes are post-mitotic cells and Schwann cells only get into the CNS in the absence of astrocytes. Ethidium bromide (EB) is a gliotoxic chemical that when injected locally within the CNS, induce demyelination. In the EB model of demyelination, glial cells are destroyed early after intoxication and Schwann cells are free to approach the naked central axons. In normal Wistar rats, regeneration of lost myelin sheaths can be achieved as early as thirteen days after intoxication; in Wistar rats immunosuppressed with cyclophosphamide the process is delayed and in rats administered cyclosporine it may be accelerated. Aiming the enlightening of those complex processes, all events concerning the myelinating cells in an experimental model are herein presented and discussed.

Uso de membranas de Nafion para a construção de sensores ópticos para medidas de pH

The behaviour of Nafion® polymeric membranes containing acid-base dyes, bromothymol blue (BB) and methyl violet (MV), were studied aiming at constructing an optical sensor for pH measurement. BB revealed to be inadequate for developing sensing phases due to the electrostatic repulsion between negative groups of their molecules and the negative charge of the sulfonate group of the Nafion®, which causes leaching of the dye from the membrane. On the other hand, MV showed to be suitable due to the presence of positive groups in its structure. The membrane prepared from a methanolic solution whose Nafion®/dye molar ratio was 20 presented the best analytical properties, changing its color from green to violet in the pH range from 0.6 to 3.0. The membrane can be prepared with good reproducibility, presenting durability of ca. 6 months and response time of 22 s, making possible its use for pH determination in flow analysis systems.

Supercritical CO2 recovery of caffeine from green coffee oil: new experimental solubility data and modeling

The caffeine solubility in supercritical CO2 was studied by assessing the effects of pressure and temperature on the extraction of green coffee oil (GCO). The Peng-Robinson¹ equation of state was used to correlate the solubility of caffeine with a thermodynamic model and two mixing rules were evaluated: the classical mixing rule of van der Waals with two adjustable parameters (PR-VDW) and a density dependent one, proposed by Mohamed and Holder² with two (PR-MH, two parameters adjusted to the attractive term) and three (PR-MH3 two parameters adjusted to the attractive and one to the repulsive term) adjustable parameters. The best results were obtained with the mixing rule of Mohamed and Holder² with three parameters.

Flow injection green method for the quantitative analysis of ketoconazole in pharmaceutical preparations

A flow injection method for the quantitative analysis of ketoconazole in tablets, based on the reaction with iron (III) ions, is presented. Ketoconazole forms a red complex with iron ions in an acid medium, with maximum absorbance at 495 nm. The detection limit was estimated to be 1×10--4 mol L-1; the quantitation limit is about 3×10--4 mol L-1 and approximately 30 determinations can be performed in an hour. The results were compared with those obtained with a reference HPLC method. Statistical comparisons were done using the Student's t procedure and the F test. Complete agreement was found at the 0.95 significance level between the proposed flow injection and the HPLC procedures. The two methods present similar precision, i.e., for HPLC the mean relative standard deviation was ca. 1.2% and for FIA ca. 1.6%.

Behaviour of albino and melanic variants of Biomphalaria glabrata Say, 1818 (Mollusca: Planorbidae) following infection by Schistosoma mansoni Sambon, 1907

The behaviour of the albino and melanic variants of Biomphalaria glabrata of Belo Horizonte (MG. Brazil) was studied comparatively, in terms of their respective susceptibilities to infection by Schistosoma mansoni of the same origin, through observation of the elimination of cercariae for a three-month period and the calculation of mortality and infection rates, in control and in infected snails. The number of amoebocytes, granulocytes and hyalinocytes in the circulating hemolymph during different periods of infection was analyzed. The evolution of the infection in the tissues was observed by means of histological cross-sections. The melanic variant showed greater susceptibility to infection and a higher mortality rate. The albino variant showed a higher number of circulating amoebocytes, both granulocytes and hyalinocytes. A higher number of degenerated sporocysts were seen in the histological cross-sections of the albino variant. The results suggest that the melanic variant of B. glabrata was more susceptible to infection by S. mansoni than was the albino variant.