Life history of the bird cherry-oat aphid, Rhopalosiphum padi (Homoptera: Aphididae), on transgenic and untransformed wheat challenged with barley yellow dwarf virus

The life history of Rhopalosiphum padi (L.) was monitored on transgenic and untransformed (soft white winter wheat plants that were infected with Barley yellow dwarf virus (BLDV), noninfected, or challenged with virus-free aphids under laboratory conditions. Two transgenic soft white winter wheat genotypes (103.1J and 126.02) derived from the parental variety Lambert and expressing the barley yellow dwarf virus coat protein gene, and two untransformed varieties, virus-susceptible Lambert and virus-tolerant Caldwell, were tested. B. padi nymphal development was significantly longer on the transgenic genotypes infected with BYDV, compared with noninfected transgenic plants. In contrast, nymphal development on Lambert was significantly shorter on BYDV-infected than on noninfected plants. Nymphal development on noninfected Lambert was significantly longer than on noninfected transgenics. No significant difference in nymphal development period was detected between virus-infected and noninfected Caldwell. Aphid total fecundity, length of reproductive period, and intrinsic rate of increase were significantly reduced on BYDV-infected transgenic plants compared with BYDV-infected Lambert. In contrast, reproductive period, total adult fecundity, and intrinsic rate of increase on noninfected Lambert were significantly reduced compared with noninfected transgenics. Transgenic plants infected with BYDV were inferior hosts for R. padi compared with infected Lambert. However, noninfected transgenics were superior hosts for aphids than noninfected Lambert. Moderate resistance to BYDV, as indicated by a significantly lower virus titer, was detected in the transgenic genotypes compared with the untransformed ones. Results show for the first time that transgenic virus resistance in wheat can indirectly influence R. padi life history.     

Selective method of isolating mutants sensitive to ultraviolet radiation from a culture of Rhodopseudomonas sphaeroides

The method of penicillin selection used after UV-irradiation (lambda = 254 nm) allows one to select UV-sensitive mutants (uvs-mutants) of the phototrophous bacterium Rhodopseudomonas sphaeroides induced by nitrosomethylurea with an effectiveness greater by an order of magnitude. Over 30% of the uvs-mutants obtained using this method had an elevated sensitivity not only to far-UV (F-UV, lambda = 254 nm) but also to near-UV (N-UV, lambda greater than 280 nm) UV-irradiation. No correlation was found in the degree of sensitivity to F-UV and N-UV-irradiation of the uvs-mutants. Mutants highly sensitive to the lethal action of N-UV were isolated.     

Spectral and photometric characteristics of different batches of auramine O (OO)]

The spectra of absorption and fluorescence of Auramine O (OO) specimens in water solution and in cells, stained with Schiff-type auramine-SO2 reagents for DNA, were investigated. Using different specimens of the stain the accuracy and sensitivity of the cytofluorometric method were estimated by the next parameters: the value of the useful signal from the nucleus (no), the value of the production of no by the time constant of fading (tau), the value of proportion of the signal to the background (no/nphi) and, in addition, the value of the variation coefficient under the measurement of the rat liver tetraploid cells. The purity of the dye was shown to interfere largely with accuracy and sensitivity of the above method. Auramine 00 of the Reanal production appeared to have the best photometricl characteristics. For this, the maxima of the absorption spectrum in the 320--700 nm region in the solution and in the cell were 371 and 433 nm, and 375 and 436 nm, resp. The maximum of the fluorescence spectrum was found 521 nm and 526 nm, resp. for the solution (0.02%) and for the Auramine-SO2 treated cells. Moreover, an isomer of Auramine O (00) -- Auramine G can be used for detection and photometrical measurement of DNA and glycogen after the Feulgen and PAS reactions, resp.     

Competition between introduced <Emphasis Type="Italic">Bradyrhizobium japonicum</Emphasis> strains and indigenous bradyrhizobia in Minnesota organic farming systems

Organic farmers recognize the importance of rhizobial associations with legume plants to help meet N fertility and plant productivity needs. A field experiment was done at three organic fields in Minnesota to assess the effect of indigenous Bradyrhizobium japonicum ORGS3 and ORGS5 and reference USDA 110 strains on the growth and yield performance of soybean. Soybean genotypes MN1505SP and Lambert inoculated with B. japonicum ORGS3 had significantly greater (P < 0.01) nodule numbers (42.1 ± 2.5), herbage N-contents (4.02 ± 0.01%), dry biomass (12.60 ± 1.45 g), and plant populations (117,890 ± 288.13 plant/acre) compared with the un-inoculated control. Grain yields were not affected by inoculation. Most nodules formed on non-inoculated Lambert (70%) and MN1505SP (53%) were occupied by strain ORGS5. The inoculant strains USDA110 and ORGS5 increased nodule occupancy by 10% on MN1505SP and Lambert. In contrast, strain ORGS3, and the combination of strains ORGS5 plus ORGS3, increased nodules occupancy on Lambert by 23 and 20%, respectively, compared with the control. The majority of nodules on Lambert (59%) and MN1505SP (52%) in the Farmington and Lamberton fields, respectively, were occupied by ORGS5. In contrast, 41 and 45% of nodules formed on Lambert and MN1505SP at Rosemount, respectively, were occupied by strain ORGS3. The lowest percentage of nodules formed on Lambert (4%) and MN1505SP (5%), in the Farmington field, were occupied by USDA110. These results showed that Bradyrhizobium strains ORGS3 and ORGS5 can be used to enhance N fixation and productivity of organically-grown soybeans grown in Minnesota fields.     

One Dimensional Plasmonic Grating: High Sensitive Biosensor

We report a simple 1D grating device fabrication on ～50 nm gold (Au) film deposited on glass, which is employed as a high performance refractive index (RI) sensor by exploiting the surface plasmon polaritons (SPP) excited by the grating device along the Au/analyte interface. A finite element analysis (FEA) method is employed to maximize the sensitivity of the sensor for a fixed period and thickness of a gold film and its close correspondence with experiment has given the insight for high sensitivity and enhanced transmission. Significantly, in the context of economic design and performance, it is shown that an optimally designed and fabricated 1D grating can be as sensitive as 524 nm/RIU (linearity RI?=?1.33303 to 1.47399), which is remarkably higher than existing reports operating in a similar wavelength region.     

Plasmonic Biosensor Based on Triangular Au/Ag and Au/Ag/Au Core/Shell Nanoprisms onto Indium Tin Oxide Glass

Gold–silver core–shell triangular nanoprisms (Au/AgTNPs) were grown onto transparent indium tin oxide (ITO) thin film-coated glass substrate through a seed-mediated growth method without using peculiar binder molecules. The resulting Au/AgTNPs were characterized by scanning electron microscopy, atomic force microscopy, X-ray diffraction, UV–vis spectroscopy, and cyclic voltammograms. The peak of dipolar plasmonic resonance was located at near infrared region of ～700 nm, which showed the refractive index (RI) sensitivity of 248 nm/RIU. Moreover, thin gold shells were electrodeposited onto the surface of Au/AgTNPs in order to stabilize nanoparticles. Compared with the Au/AgTNPs, this peak of localized surface plasmon resonance (LSPR) was a little red-shift and decreased slightly in intensity. The refractive index sensitivity was estimated to be 287 nm/RIU, which showed high sensitivity as a LSPR sensing platform. Those triangular nanoprisms deposited on the ITO substrate could be further functionalized to fabricate LSPR biosensors. Results of this research show a possibility of improving LSPR sensor by using core–shell nanostructures.     

The status of Acleotrema Johnston & Tiegs, 1922 and Heteroplectanum Rakotofiringa, Oliver & Lambert, 1987 (Monogenoidea: Diplectanidae), with the redescription of Acleotrema girellae Johnston & Tiegs, 1922

Acleotrema Johnston & Tiegs, 1922 is resurrected and its diagnosis amended. A. girellae Johnston & Tiegs, 1922 is redescribed based on the lectotype from the Australian Museum (Sydney, Australia). A. kyphosi Yamaguti, 1968 is considered a junior synonym of A. girellae. Heteroplectanum Rakotofiringa, Oliver & Lambert, 1987 is considered a junior synonym of Acleotrema. The nine species of the latter genus are transferred to Acleotrema as: A. diplobulbus (Yamaguti, 1968) n. comb., A. nenue (Yamaguti, 1968) n. comb., A. spiculare (Yamaguti, 1968) n. comb., A. yamagutii (Oliver, 1983) n. comb., A. nenuoides (Rakotofiringa, Oliver & Lambert, 1987) n. comb., A. parastromatei (Rakotofiringa, Oliver & Lambert, 1987) n. comb., A. serrulopenis (Rakotofiringa, Oliver & Lambert, 1987) n. comb., A. tamatavense (Rakotofiringa, Oliver & Lambert, 1987) n. comb. and A. oliveri (León-Règagnon, Pérez-Ponce de León & Garcia- Prieto, 1997) n. comb. An historical account of the species of Acleotrema is presented.     

Spectral sensitivity of the compound eye in butterflies (Heliconius)

Summary The spectral sensitivity of the compound eye in three butterfly species (Heliconius erato, H. numata, H, sara) was tested electrophysiologically in the wavelength region 310 to 650 nm. Sensitivity maxima were found at 370 to 390 nm, 450 to 470 nm, and 550 to 570 nm, for all species. The three sensitivity maxima are suggested to be due to different photoreceptor types effecting wave-length discrimination. An interspecies difference in spectral sensitivity was also found. The difference is suggested to be due to the relative number of photoreceptors of each type. In some of the present experiments a small discontinuity in sensitivity was found at 610 or 630 nm. It is probably caused by a selective reflection of these wavelengths from a tapetum.     

Serum protein determination by high-performance gel-permeation chromatography

A general high-performance gel-permeation chromatography (HPGPC) method was developed to determine protein in human serum with improved sensitivity and speed. The optimum UV wavelength for protein detection was found to be 210 nm, by comparing the protein values obtained by varying the UV wavelength of the HPLC detection system with the protein values obtained from spectrophotometric protein assays, i.e., the bicinchoninic acid (BCA) method and the biuret method. The analysis time was less than 1 min. Since this HPGPC serum protein assay method is simple and rapid, it is expected to be particularly well adapted for use in clinical laboratories.     

Accessibility to bacterial nucleic acids of the intercalating drug aliphatic amino acid ellipticinium derivatives in Escherichia coli and Salmonella typhimurium

The fluorescence of the aliphatic (amino acido)-N2-methyl-9-hydroxyellipticinium (AA-NMHE) derivatives [Auclair, C., Voisin, E., Banoun, H., Bernardou, J., Meunier, B., & Paoletti, C. (1984) J. Med. Chem. 27, 1161-1166], namely, dehydroglycino-NMHE, dehydroalanino-NMHE, dehydrovalino-NMHE, and dehydroleucino-NMHE, has been characterized. The changes in the fluorescence properties of the drugs, including increase in quantum yields, increase in fluorescence lifetimes, and occurrence of energy transfer upon binding to DNA in vitro, have been further investigated. The measurement of the fluorescence increment of AA-NMHE when bound to fluorescent sites inside intact bacteria has been found to be suitable for the determination of the accessibility of the drugs to bacterial nucleic acids according to the method of Lambert and Le Pecq [Lambert, B., & Le Pecq, J.B. (1984) Biochemistry 23, 166-176]. With this methodology, the kinetics of drug uptake, the ability of the drug to reach the bacterial nucleic acids at equilibrium, and the nature of the ligand binding model have been determined in two AA-NMHE-sensitive strains, Escherichia coli BL 101 (Lambert & Le Pecq, 1984) and Salmonella typhimurium TA 98 [Ames, B.N., Lee, F.D., & Durston, W.E. (1973) Proc. Natl. Acad. Sci. U.S.A. 70, 782-786]. The main results obtained are the following: At nonsaturating concentrations, each AA-NMHE exhibits a marked difference in its ability to reach the bacterial nucleic acids. This parameter seems to be correlated with the antibacterial efficiency of the drugs.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison between woody indexing and a rapid hybridisation assay for the diagnosis of little cherry disease in cherry trees*

Sweet cherry (Prunus avium) and sour cherry (Prunus cerasus) trees from orchards in the Kootenay and Okanagan Valleys of British Columbia, Canada were assayed for the presence of little cherry disease by three different methods: Northern blot analysis of double-stranded RNA, woody indexing for fruit symptoms on sweet cherry cv. Lambert, and woody indexing for foliar symptoms on cv. Canindex 1. Results of the three methods were in agreement for 85% of the samples. Of the 78 orchard trees tested, double-stranded RNA isolated from 48 trees hybridised with a radiolabeled cloned probe specific for little cherry disease. When the 48 trees were tested by woody indexing, buds from 41 trees induced fruit symptoms on cv. Lambert, but only 32 yielded foliar symptoms on cv. Canindex 1 under the conditions of the experiment. Of the 30 orchard trees that did not yield a positive response to the Northern blot analysis, 26 samples were negative on cv. Lambert and 26 were negative on cv. Canindex 1. Northern blot analysis of the 78 cv. Lambert indicator trees revealed that there was an absolute correlation between the presence of little cherry disease-associated double-stranded RNA and the development of typical little cherry disease symptoms on the indicator trees. Reliability of woody indexing of orchard samples was impaired by poor transmission of the disease from the inoculating bud to the indicator tree. Woody indexing with cv. Canindex 1 was particularly prone to a large number of apparently erroneous negative results. Of the three protocols used, diagnosis of little cherry disease by Northern blot analysis was found to be the most reliable and offered a greatly accelerated means of diagnosis.     

共振瑞利散射测定痕量甲胎蛋白含量研究

用共振瑞利散射光谱研究磷钼杂多酸与甲胎蛋白的相互作用的过程中,发现其结合会引起共振瑞利散射(RRS),最大RRS峰均位于480 nm。在一定浓度范围内,AFP浓度与散射强度成正比,这样就产生了一种新的利用共振光散射强度定量测定甲胎蛋白的方法。本文对该反应体系的适宜反应条件、主要影响因素、散射强度与AFP浓度的关系、方法的灵敏度等,进行了比较研究。发现不同的杂多酸对于甲胎蛋白的检出限(3σ)在5.2~78μg.L-1之间,其中以磷锑钼酸体系灵敏度最高,对于甲胎蛋白(AFP)的检出限为2.5μg.L-1。该方法具有操作简便、灵敏度高、线性范围宽等优点。考察了共存物质的干扰影响,获得了满意的结果。     

Column-switching techniques for high-performance liquid chromatography of ibuprofen and mefenamic acid in human serum with short-wavelength ultraviolet detection

Column-switching techniques for high-performance liquid chromatography of two acidic drugs, ibuprofen and mefenamic acid, in human serum with short-wavelength ultraviolet detection are described. The method involved extraction of the analyte from acidified serum followed by the chromatographic analysis using column switching. Three ODS columns were used each with different mobile phase, utilizing the difference of ion-pair formation or of ionization caused by pH change. The method offered high sensitivity and selectivity, with short-wavelength ultraviolet detection at 221 nm for ibuprofen and at 219 nm for mefenamic acid. The detection limits were 0.5 ng/ml (2.4 pmol/ml) for ibuprofen and 0.1 ng/ml (0.4 pmol/ml) for mefenamic acid using 1 ml of serum, both at a signal-to-noise ratio of 3. With some modifications, the principle of the method would be applicable to other acidic compounds in biological fluids.     

A simple method to determine trypsin and chymotrypsin inhibitory activity

A colorimetric method for serine protease inhibition was modified using N-Acetyl-DL-Phenylalanine beta-Naphthylester (APNE) as the substrate and o-Dianisidine tetrazotized (oD) as the dye. The reaction generated a single peak absorbing at 530 nm for both trypsin and chymotrypsin. Standard curves with increasing enzyme concentrations showed strong linearity. A standard curve for the serine protease inhibitor, Bowman-Birk Inhibitor (BBI), has been made using this modified method. The IC50 for 3 U of trypsin was found to be 33 ng and the IC50 obtained for 3 mU of chymotrypsin was 53 ng. A recombinant BBI (rBBI) gene was constructed, cloned and expressed in the yeast Pichia pastoris. Evaluating samples of rBBI for protease inhibitory activity by the gel activity method failed to quantify the inhibitor amounts, due to high sensitivity for trypsin inhibition and low sensitivity for chymotrypsin inhibition. After development, the results could not be quantified, even to the extent that 1 microl of rBBI could not be detected with chymotrypsin inhibition. Therefore, a modified method for trypsin and chymotrypsin inhibition was used to evaluate the level of rBBI-expression for these same samples. The level of rBBI expression was calculated to be 50-56 ng/microl of media. These amounts fit into the range of values previously obtained by Western blot analysis. This modified method allows us to combine the sensitivity of the gel activity method with the quantification attributes of a Western blot. Thus, the modified method represents a significant improvement in speed, sensitivity and reproducibility over the gel activity method.     

C-terminal truncation of bovine protein disulfide isomerase increases its activity.

Protein disulfide isomerase as usually purified by the method of Lambert and Freedman (Biochem. J., 1983, 213, 225-234) although appeared homogeneous by sodium dodecyl sulfate-polyacrylamide gel electrophoresis can be separated into two major components on a size-exclusion high performance liquid chromatography column or by polyacrylamide gel electrophoresis. These two components have the same N-terminal sequences but the C-terminal sequences are different, suggesting that one is the C-terminal slightly truncated protein. The shortened protein is more active in both the isomerase and the thiol-protein oxidoreductase activities.     

Effect of Gold Coating on Sensitivity of Rhombic Silver Nanostructure Array

The sensitivity is the most important parameter in the sensing field. Effort was made to study the effect of gold coating on the sensitivity of rhombic silver nanostructure array through numerical simulation using the discrete dipole approximation method. This study shows that thickness of the gold coating can be varied to tune the sensitivity of the rhombic silver nanostructure array. The Au–Ag nanostructure array is found to possess the maximum refractive index sensitivity of 714 nm/RIU when thickness of gold is 20 nm, thickness of silver is 25 nm, and refractive index of the medium is around 1.35. The condition for achieving the maximum refractive index sensitivity can be used for detecting many species of biomolecules and drugs in the future.     

Real-time optical detection of single human and bacterial viruses based on dark-field interferometry

The rapid and sensitive detection and characterization of human viruses and bacteriophage is extremely important in a variety of fields, such as medical diagnostics, immunology and vaccine research, and environmental contamination and quality control. We introduce an optical detection scheme for real-time and label-free detection of human viruses and bacteriophage as small as ~24 nm in radius. Combining the advantages of heterodyne interferometry and dark-field microscopy, this label-free method enables us to detect and characterize various biological nanoparticles with unsurpassed sensitivity and selectivity. We demonstrate the high sensitivity and precision of the method by analyzing a mixture containing HIV virus and bacteriophage. The method also resolves the distribution of small nano-impurities (~20-30 nm) in clinically relevant virus samples.     

Monogeneans from Pangasiidae (Siluriformes) in Southeast Asia: X. six new species of Thaparocleidus Jain, 1952 (Ancylodiscoididae) from Pangasius micronema

The examination of gill parasites from Pangasius micronemao Bleeker, 1847 (Siluriformes, Pangasiidae) in Southeast Asia revealed the presence of nine species of Monogenea. Two (Thoparocleidus brevicochleus Pariselle, Lim & Lambert, 2001 and T. sinespinoe Pariselle, Lim & Lambert, 2001) have been previously described. Among the others, six species, belonging to Thaporocleidus Jain, 1952 (Monogenea, Ancylodiscoididae) as defined by Lim (1996) and Lim et al. (2001), are considered new species: T. tacitus n. sp., T. summagracilis n. sp., T. portentosus n. sp., T rukyonii n. sp., T. durandi n. sp., and T. lebrunce n. sp. The remaining species is represented by too few individuals to be conclusively described.     

An o-toluidine method for detection of carbohydrates in protein hydrolysates

The o-toluidine high-performance thin-layer chromatography (HPTLC) method for detection of reducing sugars has been demonstrated to be a facile method for composition analysis of protein hydrolysates with a maximum sensitivity range of 50-100 pmol. The solution phase reaction of o-toluidine with reducing sugars has been previously used for spectrophotometric detection of glucose at 480-630 nm. In contrast, the heterogeneous reaction of o-toluidine with reducing sugars resolved by thin-layer chromatography produces chromophoric derivatives which have a broad absorbance at 295 nm. Detection of these chromophoric derivatives is achieved by uv diffuse reflectance scanning densitometry. It is demonstrated that detection limits of less than 10 ng can be achieved by using HPTLC plates and is therefore equal or more sensitive for some sugars than recently reported high-pressure liquid chromatography methods using amperometric or fluorescence detection.     

A frequency view of colour: measuring the human sensitivity to square-wave spectral power distributions.

We have measured the chromatic threshold sensitivity to stimuli with spectral composition determined by a periodic function of energy over wavelength. This approach is analogous to frequency studies of spatial vision for the study of colour. A device was constructed permitting the synthesis of illuminants over the entire visible range (400-700 nm) in which phase, frequency and amplitude can be independently controlled. We have used 12 frequencies of square-wave functions (from 0.5 to 3.6 cycles/300 nm) and seven values of phase (between 0 degrees and 180 degrees) to obtain the contrast sensitivity function of the chromatic system in three normal trichromats. The results show maximum sensitivity around 1.5 cycles/300 nm and a high-frequency cut-off at 3.6 cycles/300 nm. These empirical values are compared with the predictions obtained from three current psychophysical models of opponent-colour process.