Alteration of surfactant protein A expression in renal cell carcinoma

Surfactant protein-A (SP-A) belongs to a family of collagen-containing C-type lectins called collectins. SP-A is expressed by renal tubule epithelial cells. We investigated the distribution of SP-A in renal cell carcinomas (RCC) using immunohistochemical techniques and western blotting. We used 35 formalin fixed, paraffin embedded (FFPE) RCC tissue samples. We compared results with clinico-pathological parameters of RCC including age, sex, Fuhrman grade, tumor volume, tumor node metastasis (TNM) and clinical stage. SP-A was localized in the glomerulus and renal tubule epithelium in nontumor tissue and strong SP-A immunoreactivity was observed in tumor tissue. SP-A was expressed in the RCC tumor cells (64%) and nontumor cells (34%) in males and RCC tumor cells (90%) and nontumor cells (30%) in females. There was a significant correlation between SP-A immunoreactivity in tumor cells and gender, age, tumor diameter, Fuhrman grade and tumor diameter. Western blot analysis supported the immunohistochemical findings. We present evidence for involvement of SP-A in RCC and suggest that increased SP-A expression in RCC is associated with favorable prognosis.     

Palatability and feeding preferences of Uresiphita maorialis (Lepidoptera: Crambidae) for three Sophora species

In a three-hour bioassay, we tested the palatability and feeding preferences of Uresiphita maorialis (kōwhai moth) for Sophora tetraptera, Sophora microphylla and Sophora prostrata. Palatability tests showed no differences among the Sophora species. Feeding preferences, on the other hand, showed that S. tetraptera and S. microphylla leaves are preferred over S. prostrata leaves. Our results support our field observations in Wellington city parks and gardens showing that S. tetraptera and S. microphylla plants frequently have higher densities of larvae than S. prostrata.     

Market analysis of biosensors for food safety

This paper is presented as an overview of the pathogen detection industry. The review includes pathogen detection markets and their prospects for the future. Potential markets include the medical, military, food, and environmental industries. Those industries combined have a market size of $563 million for pathogen detecting biosensors and are expected to grow at a compounded annual growth rate of 4.5%. The food market is further segmented into different food product industries. The overall food-pathogen testing market is expected to grow to $192 million and 34 million tests by 2005. The trend in pathogen testing emphasizes the need to commercialize biosensors for the food safety industry as legislation creates new standards for microbial monitoring. With quicker detection time and reusable features, biosensors will be important to those interested in real time diagnostics of disease causing pathogens. As the world becomes more concerned with safe food and water supply, the demand for rapid detecting biosensors will only increase.     

Nanowire labeled direct-charge transfer biosensor for detecting Bacillus species

A direct-charge transfer (DCT) biosensor was developed for the detection of the foodborne pathogen, Bacillus cereus. The biosensor was fabricated using antibodies as the sensing element and polyaniline nanowire as the molecular electrical transducer. The sensor design consisted of four membrane pads, namely, sample application, conjugate, capture and absorption pads. Two sets of polyclonal antibodies, secondary antibodies conjugated with polyaniline nanowires and capture antibodies were applied to the conjugate and the capture pads of the biosensor, respectively. The detection technique was based on capillary flow action which allowed the liquid sample to move from one membrane to another. The working principle involved antigen-antibody interaction and direct electron charge flow to generate a resistance signal that was being recorded. Detection from sample application to final results was completed in 6 min in a reagentless process. Experiments were conducted to find the best performance of the biosensors by varying polyaniline types and concentrations. Polyaniline protonated with hydrochloric acid, emeraldine salt and polyaniline protonated with perchloric acid were the three kinds of polyaniline used in this study. The biosensor sensitivity in pure cultures of B. cereus was found to be 10(1) to 10(2)CFU/ml. Results indicated that using emeraldine salt at a concentration of 0.25 g/ml gave the best biosensor performance in terms of sensitivity. The biosensor was also found to be specific in detecting the presence of B. cereus in a mixed culture of different Bacillus species and other foodborne pathogens. The speed, sensitivity and ease-of-use of this biosensor make it a promising device for rapid field-based diagnosis towards the protection of our food supply chain. The phenotypic and genotypic similarities between B. cereus and Bacillus anthracis will also allow this biosensor to serve as an excellent model for the detection of B. anthracis.     

Effect of unilateral and bilateral resistance exercise on maximal voluntary strength,total volume of load lifted,and perceptual and metabolic responses

The present study investigated the effect of unilateral and bilateral resistance exercise (RE) on maximal voluntary strength, total volume of load lifted (TVLL), rating of perceived exertion (RPE) and blood lactate concentration of resistance-trained males. Twelve healthy men were assessed for the leg extension one-repetition maximum (1RM) strength using bilateral and unilateral contractions. Following this assessment, an RE session (3 sets of repetitions to failure) was conducted with bilateral and unilateral (both limbs) contractions using a load of 50% 1RM. The TVLL was calculated by the product of the number of repetitions and the load lifted per repetition. RPE and blood lactate were measured before, during and after each set. Session RPE was measured 30 minutes after RE sessions. There was a significant difference in the bilateral (120.0±11.9) and unilateral (135.0±20.2 kg) 1RM strength (p < 0.05). The TVLL was similar between both RE sessions. Although the repetitions decreased with each successive set, the total number of repetitions completed in the bilateral protocol (48) was superior to the unilateral (40) protocol (p < 0.05). In both bouts, RPE increased with each subsequent set whilst blood lactate increased after set 1 and thereafter remained stable (p < 0.05). The RPE and lactate responses were not significantly different between both sessions. In conclusion, a bilateral deficit in leg extension strength was confirmed, but the TVLL was similar between both RE sessions when exercising to voluntary fatigue. This outcome could be attributed to the number of repetitions completed in the unilateral RE bout. The equal TVLL would also explain the similar perceptual and metabolic responses across each RE session.     

三氧化二砷对食管癌细胞增殖和热休克蛋白70表达的影响

目的：研究三氧化二砷（As2O3）对食管癌细胞增殖和热休克蛋白70（HSP70）表达的影响。方法：通过相差显微镜、流式细胞术、免疫细胞化学染色和免疫印迹分析等方法观察As2O3对人食管癌细胞株EC1的作用效果和作用机制。结果：与对照组相比,经2μmol/L和5μmol/Las2O3作用的细胞出现明显的生长抑制,G2/M期细胞比例增加;2μmol/Las2O3作用48h后经Ecl细胞HSP70（heat shock protein70）及HSC70(heat shock cognate protein70)表达均增加。结论：As2O3诱导食管癌细胞G2/M期阻滞抑制细胞增殖和生长;HSP70的升高是细胞对As2O3作用后出现的应激反应,并与细胞周期阻滞相关。     

Electrically active polyaniline coated magnetic (EAPM) nanoparticle as novel transducer in biosensor for detection of Bacillus anthracis spores in food samples

Electrically active polyaniline coated magnetic (EAPM) nanoparticle-based biosensor has been developed for the detection of Bacillus anthracis endospores in contaminated food samples. The 100 nm-diameter EAPM nanoparticles are synthesized from aniline monomer (made electrically active by acid doping) coating the surface of gamma iron oxide cores. The magnetic, electrical, and structural characteristics of the synthesized EAPM nanoparticles have been studied using superconducting quantum interference device (SQUID), four-point probe, and transmission electron microscopy (TEM). Room temperature hysteresis of the synthesized nanoparticles shows a saturation magnetization value of 44.1 emu/g. The EAPM nanoparticles are biologically modified to act as an immunomagnetic concentrator of B. anthracis spores from lettuce, ground beef and whole milk samples and are directly applied to a direct-charge transfer biosensor. The detection mechanism of the biosensor depends on the capillary flow of the captured spores on the biosensor surface along with direct-charge transfer across the EAPM nanoparticles. Experimental results indicate that the biosensor is able to detect B. anthracis spores at concentrations as low as 4.2 x 10(2)spores/ml from the samples. The EAPM-based biosensor detection system is fast and reliable with a total detection time of 16 min.     

Performance enhancement of polyaniline-based polymeric wire biosensor

We demonstrate here the performance enhancement of polyaniline-based biosensor using screen-printing technology and pulse mode measurement technique. Screen-printed silver electrodes were made on a nitrocellulose membrane and the distance between the two electrodes was approximately 550 microm. Resistance of the electrodes had an average of 1.4 Omega with a standard deviation of +/-0.4 Omega. The surface of nitrocellulose membrane was modified by glutaraldehyde to immobilize streptavidin. Biotinylated anti-mouse IgG was conjugated with polyaniline-coated magnetic nanoparticles. Formation of polyaniline-coated magnetic nanoparticles was confirmed by a transmission electron microscope image. The polyaniline was used as an electric signal transducer for the monitoring of the biospecific binding event. An electrical response induced by the streptavidin-biotin interaction was measured by pulse mode measurement. This measurement method reduced the resistance caused by interfacial capacitance. Dose-dependent resistance changes were also successfully analyzed by the pulse mode polymeric wire biosensor. Results showed that the pulse mode measurement technique enhanced the performance of the polyaniline-based polymeric wire biosensor by reducing the interfacial effects. This approach could be helpful in samples with high interfering background materials, such as food and clinical specimens.     

Intragenic duplication and divergence in the spectrin superfamily of proteins

Many structural, signaling, and adhesion molecules contain tandemly repeated amino acid motifs. The alpha-actinin/spectrin/dystrophin superfamily of F-actin-crosslinking proteins contains an array of triple alpha-helical motifs (spectrin repeats). We present here the complete sequence of the novel beta-spectrin isoform beta(Heavy)- spectrin (beta H). The sequence of beta H supports the origin of alpha- and beta-spectrins from a common ancestor, and we present a novel model for the origin of the spectrins from a homodimeric actin-crosslinking precursor. The pattern of similarity between the spectrin repeat units indicates that they have evolved by a series of nested, nonuniform duplications. Furthermore, the spectrins and dystrophins clearly have common ancestry, yet the repeat unit is of a different length in each family. Together, these observations suggest a dynamic period of increase in repeat number accompanied by homogenization within each array by concerted evolution. However, today, there is greater similarity of homologous repeats between species than there is across repeats within species, suggesting that concerted evolution ceased some time before the arthropod/vertebrate split. We propose a two-phase model for the evolution of the spectrin repeat arrays in which an initial phase of concerted evolution is subsequently retarded as each new protein becomes constrained to a specific length and the repeats diverge at the DNA level. This evolutionary model has general applicability to the origins of the many other proteins that have tandemly repeated motifs.      

Fluorescent bio-barcode DNA assay for the detection of Salmonella enterica serovar Enteritidis

Salmonella enterica serovar Enteritidis is one of the most frequently reported causes of foodborne illness. It is a major threat to the food safety chain and public health. A highly amplified bio-barcode DNA assay for the rapid detection of the insertion element (Iel) gene of Salmonella Enteritidis is reported in this paper. The biosensor transducer is composed of two nanoparticles: gold nanoparticles (Au-NPs) and magnetic nanoparticles (MNPs). The Au-NPs are coated with the target-specific DNA probe which can recognize the target gene, and fluorescein-labeled barcode DNA in a 1:100 probe-to-barcode ratio. The MNPs are coated with the 2nd target-specific DNA probe. After mixing the nanoparticles with the 1st target DNA, the sandwich structure (MNPs-2nd DNA probe/Target DNA/1st DNA probe-Au-NPs-barcode DNA) is formed. A magnetic field is applied to separate the sandwich from the unreacted materials. Then the bio-barcode DNA is released from the Au-NPs. Because the Au-NPs have a large number of barcode DNA per DNA probe binding event, there is substantial amplification. The released barcode DNA is measured by fluorescence. Using this technique, the detection limit of this bio-barcode DNA assay is as low as 2.15 x 10(-16)mol (or 1 ng/mL).