Pathotyping of Newcastle disease virus with a filamentous bacteriophage

A filamentous phage bearing the peptide sequence TLTTKLY was isolated from a heptapeptide phage display library against a velogenic Newcastle disease virus (NDV). In order to investigate the potential of this specific phage as an immunological reagent in virus pathotyping, an enzyme-linked immunosorbent assay (ELISA)-based method was developed. This method can differentiate the velogenic strains from the mesogenic and lentogenic strains. An equilibrium-binding assay in solution showed that the interactions between the phage and all the NDV strains gave rise to two widely differing dissociation constants (Kdrel). Based upon the first Kdrel values, NDV strains can be classified into two groups; the first comprises the velogenic strains, and the second consists of the mesogenic and lentogenic strains. These results indicate a high degree of correlation between the binding affinities and pathotyping of NDV strains using the TLTTKLY phage.     

Dietary ganglioside decreases cholesterol content, caveolin expression and inflammatory mediators in rat intestinal microdomains

Membrane microdomains rich in cholesterol and sphingolipids, including gangliosides (GGs), are known to be important regions for cell signaling and binding sites for various pathogens. Cholesterol depletion inhibits the cellular entry of pathogens and also reduces inflammatory signals by disrupting microdomain structure. Our previous study showed that dietary gangliosides increased total ganglioside incorporation while decreasing cholesterol in the intestinal mucosa. We hypothesized that diet-induced reduction in cholesterol content in the intestinal mucosa disrupts microdomain structure resulting in reduced pro-inflammatory signals. Male weanling Sprague-Dawley rats were fed semipurified diets for 2 weeks. Experimental diets were formulated to include either ganglioside-enriched lipid (GG diet, 0.02% gangliosides [w/w of diet] ) or polyunsaturated fatty acid (PUFA diet, 1% arachidonic acid and 0.5% docosahexaenoic acid, w/w of total fat), in a control diet containing 20% fat. Levels of cholesterol, GG, caveolin, platelet activating factor (PAF), and diglyceride (DG) were measured in the microdomain isolated from the intestinal brush border. The GG diet increased total gangliosides by 50% with a relative increase in GD3 and a relative decrease in GM3. Cholesterol content was also reduced by 23% in the intestinal microdomain. These changes resulted in a significant decrease in the ratio of cholesterol to ganglioside. The GG diet and the PUFA diet were both associated with reduction in caveolin, PAF, and DG content in microdomains, whereas no change occurred in the ganglioside profile of animals fed the PUFA diet. Dietary gangliosides decrease the cholesterol/ganglioside ratio, caveolin, PAF and DG content in microdomains thus exerting a potential anti-inflammatory effect during gut development.     

Hydroxyl free radicals generated by vanadyl[IV] induce cell blebbing in mitotic human Chang liver cells

Vanadium has recently been reported to induce interphase and M-phase (mitotic) programmed cell death via the generation of hydroxyl free radicals (OH*). In this paper, the effects of antioxidants on: (a) vanadyl[IV]-generated OH* free radical levels; and (b) cellular glutathione in vanadyl [IV]-treated Chang liver cells were evaluated. The surface morphology of vanadyl-treated mitotic cells was studied by confocal and scanning microscopy. The free radical scavengers zinc chloride, glucose and thiourea reduced the levels of vanadyl-induced OH* free radicals and partially prevented the depletion of cellular glutathione. Concurrent with OH* free radical production, vanadyl-treated telophase cells exhibited excessive cell blebbing and cell shrinkage. The morphological features demonstrated in vanadyl-induced mitotic programmed cell death as a consequence of oxidative stress is novel.     

Changes in CO2 Exchange Rate,Stomatal Conductance,Activities of Photosystems 1 and 2, and Chloroplast Polypeptide Profile Induced by Simulated Acidic Rain

In seedlings of Vigna radiata (L.) R. Wilczek cultivars ADT-1 and CO-5 exposed to acidic showers (H2SO4 : HNO3 : HCl, 4 : 2 : 1, v/v) of different pH (7.0, 5.5, 4.0, and 2.5) for 10 d, net CO2 uptake and stomatal conductance were reduced. The chlorophyll (Chl) a and b contents were reduced but the carotenoid (Car) content increased. In vivo Chl a fluorescence patterns of both the cultivars were altered. No significant change in photosystem (PS) 1 activity was observed except at pH 2.5 where an inhibition was evident. By contrast, PS2 activities declined rapidly with increasing acidity. The room temperature absorption spectra of isolated chloroplasts showed very little changes. SDS-PAGE analysis revealed depletion of 23, 33, and 55 kDa polypeptides. Cultivar CO-5 was more sensitive to acidic rain than cv. ADT-1.     

Biosorption of radionuclides by Rhizopus arrhizus

The sorption of various radionuclides viz. 233U, 239Pu, 241Am, 144Ce, 147Pm, 152+154Eu and 95Zr from aqueous nitrate medium has been studied using biomass Rhizopus arrhizus. The biosorption of 233U and 239Pu was found to be maximum at pH 6-7 whereas for other trivalent actinides and fission products viz. 241Am, 144Ce, 147Pm, 152+154Eu and tetravalent 95Zr, it was more effective at pH 2. This biomass is a promising sorbant for the treatment of radioactive effluents from nuclear industry. © Rapid Science Ltd. 1998     

Mixing time in a down-flow jet loop bioreactor

Mixing time was determined in a down-flow jet loop bioreactor with Newtonian and non-Newtonian fluids. It was observed that the mixing time decreased with an increase in linear liquid velocity, superficial gas velocity, draft tube to column diameter ratio, nozzle diameter and shear thinning of media. The optimum draft tube to column diameter ratio was found to be about 0.44. Correlations were presented for prediction of mixing time.List of Symbols A m² cross sectional area of the column - C kmol/m³ local tracer concentration - A _D m² flow area,A _D =/4 (D _Z ² -D _TO ² ) - D m column diameter - D _E m draft tube diameter - D _TO m outside diameter of the air tube - D _TFL m equivalent flow diameter,D _TFL =(D _Z ² -D _TO ² )^0.5 - D _z m nozzle diameter - g m/s² gravitational acceleration - h % inhomogeneity - H m height of the column - H _B m distance between the lower edge of the draft tube and the impact plate - H _T m distance between the upper edge of the draft tube and the liquid nozzle - K Pa.sⁿ consistency index in power-law model - L _E m length of the draft tube - n flow index in the power-law model - Re _j jet Reynolds number,Re _j =(D _TFL×w₁×_L)/ _eff - t _M s mixing time - t _sg m/s superficial gas velocity based onA - W _l m/s linear liquid velocity based onD _D Greek Letters N/m² shear stress - s shear rate - kg/m³ density of liquid - N/m surface tension of the liquid - Pa.sⁿ viscosity of liquid Indices X concentration at infinite time maximum value of tracer concentration - eff effective - L Liquid - obs observed - pred Predicted     

Fast gel electrophoresis to analyze DNA-protein interactions

A rapid method for electrophoresis of DNA-protein complexes is described. Popular "gel-shift" assays are performed using Pharmacia PhastSystem with its convenience of pre-cast gels and buffer strips and microprocessor-controlled high-resolution separation. Using this system, the products of a DNA binding reaction (DNA-protein complexes) can be separated from "free" DNA in less than one hour. DNA fragments as well as oligonucleotides have been used as targets with partially purified extracts containing sequence-specific DNA binding proteins. We present here a comparison of results of gel-shift assays obtained by conventional techniques and by our rapid "PhastShift" method which reduces the time, effort and technical expertise necessary to obtain reproducible results.     

A scaffoldless technique for self-generation of three-dimensional keratinospheroids on liquid crystal surfaces

We describe a new scaffold-free three-dimensional (3D) cell culture model using cholesteryl ester based lyotropic liquid crystal (LC) substrates. Keratinocytes were deposited randomly on the LC surface where they self-assembled into 3D microtissues or keratinospheroids. The cell density required to form spheroids was optimized. We investigated cell viability using dead/live cell assays. The adhesion characteristics of cells within the microtissues were determined using histological sectioning and immunofluorescence staining. Fourier transform infrared spectroscopy (FTIR) was used to characterize the biochemistry of the keratinospheroids. We found that both cells and microtissues could migrate on the LC surface. The viability study indicated approximately 80% viability of cells in the microtissues up to 20 days of culture. Strong intercellular adhesion was observed in the stratification of the multi-layered microspheroids using field emission-scanning electron microscopy (FE-SEM) and histochemical staining. The cytoskeleton and vinculins of the cells in the microtissues were expressed diffusely, but the microtissues were enriched with lipids and nucleic acids, which indicates close resemblance to the conditions in vivo. The basic 3D culture model based on LC may be used for cell and microtissue migration studies in response to cytochemical treatment.     

Advancing Optical Imaging for Breast Margin Assessment: An Analysis of Excisional Time,Cautery, and Patent Blue Dye on Underlying Sources of Contrast

Breast conserving surgery (BCS) is a recommended treatment for breast cancer patients where the goal is to remove the tumor and a surrounding rim of normal tissue. Unfortunately, a high percentage of patients return for additional surgeries to remove all of the cancer. Post-operative pathology is the gold standard for evaluating BCS margins but is limited due to the amount of tissue that can be sampled. Frozen section analysis and touch-preparation cytology have been proposed to address the surgical needs but also have sampling limitations. These issues represent an unmet clinical need for guidance in resecting malignant tissue intra-operatively and for pathological sampling. We have developed a quantitative spectral imaging device to examine margins intra-operatively. The context in which this technology is applied (intra-operative or post-operative setting) is influenced by time after excision and surgical factors including cautery and the presence of patent blue dye (specifically Lymphazurin™, used for sentinel lymph node mapping). Optical endpoints of hemoglobin ([THb]), fat ([β-carotene]), and fibroglandular content via light scattering (<µ_s’>) measurements were quantified from diffuse reflectance spectra of lumpectomy and mastectomy specimens using a Monte Carlo model. A linear longitudinal mixed-effects model was used to fit the optical endpoints for the cautery and kinetics studies. Monte Carlo simulations and tissue mimicking phantoms were used for the patent blue dye experiments. [THb], [β-carotene], and <µ_s’> were affected by <3.3% error with <80 µM of patent blue dye. The percent change in [β-carotene], <µ_s’>, and [β-carotene]/<µ_s’> was <14% in 30 minutes, while percent change in [THb] was >40%. [β-carotene] and [β-carotene]/<µ_s’> were the only parameters not affected by cautery. This work demonstrates the importance of understanding the post-excision kinetics of ex-vivo tissue and the presence of cautery and patent blue dye for breast tumor margin assessment, to accurately interpret data and exploit underling sources of contrast.     

Sorption of plutonium, americium and fission products from reprocessing effluents using Rhizopus arrhizus

Rhizopus arrhizus biomass removed more than 95% of 239Pu, 241Am, 95Zr, 144Ce and 152+154Eu from different waste streams generated in Purex as well as Truex processes after suitable adjustment of pH. © Rapid Science Ltd. 1998