bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of tea polyphenols on the activities of soybean trypsin inhibitors and trypsin
Authors: Huang Huihua , Kwok Kin‐Chor , Liang Hanhua
Published: January 2004

Tea polyphenols (TPs) and other materials were extracted from Chinese green tea, and their effects on trypsin inhibitors and trypsin were analysed. TPs were found to have a deactivation effect on both Kunitz trypsin inhibitor (KTI) and Bowman–Birk trypsin inhibitor (BBTI). KTI was more easily deactivated than BBTI by complexing with TPs. The deactivation effect of TPs on KTI and BBTI reached a maximum at a TP/KTI ratio of 25 and a TP/BBTI ratio of 16. However, the deactivation effect of TPs on KTI and BBTI was reduced dramatically when KTI and BBTI were already complexed with trypsin. TPs were also found to inhibit trypsin. The inhibitory activity of TPs, KTI and BBTI on trypsin was found to decrease in the order BBTI > gtTI > gtPs. Complete inhibition of trypsin by TPs could not be achieved. When the TP concentration was increased to about 17 µg ml−1, the residual activity of trypsin was maintained at 400 TU mg−1, equivalent to 32% of the initial trypsin activity. In TP inhibition the KM value for trypsin remained unchanged at 5.88 × 10−4 mol l−1 and Vmax decreased when benzoyl‐DL‐arginine‐p‐nitroanilide (BAPNA) was used as substrate. The pattern of trypsin inhibition by TPs is non‐competitive. Copyright © 2004 Society of Chemical Industry
Relationship between foam parameters obtained by the gas‐sparging method and sensory evaluation of sparkling wines
Authors: Gallart Magdalena , Tomás Xavier , Suberbiola Gabriel , López‐Tamames Elvira , Buxaderas Susana
Published: January 2004

The foams of 51 sparkling wines of different varieties, harvests and aging times were studied both by the Mosalux® gas‐sparging method and by sensory evaluation. The instrumental foam parameters, ie foamability (HM), Bikerman coefficient (Σ) and foam stability time (TS), and the descriptors evaluated in the sensory analysis, principally foam area, foam collar and global impression, were correlated positively. The influence of variety and harvest on the foam characteristics of sparkling wines determined from the Mosalux parameters was also reflected in the assessment by sensory analysis. The instrumental method could be applied to base wines to predict the foaming properties of the resulting sparkling wines. Copyright © 2004 Society of Chemical Industry
Effect of packaging conditions and temperature on viability of microencapsulated bifidobacteria during storage
Authors: Hsiao Hung‐Chi , Lian Wen‐Chian , Chou Cheng‐Chun
Published: January 2004

In this study, Bifidobacterium longum B6 and B infantis CCRC 14633 were microencapsulated in various wall materials, including skim milk, gum arabic, gelatin and soluble starch. The stability of these microencapsulated bifidobacteria held at 25 or 4 °C in glass or polyester bottles with or without deoxidant and desiccant was determined. Microencapsulated cells of B longum B6 were generally more stable than the corresponding microencapsulated cells of B infantis CCRC 14633 under the various storage conditions tested. The presence of deoxidant and desiccant, especially at 25 °C, increased the survival of microencapsulated cells. Furthermore, the survival of bifidobacteria was enhanced when they were stored at 4 °C in glass bottles. It was also found that the wall material affected the survival of microencapsulated bifidobacteria. The viability of B longum B6 and B infantis CCRC 14633 was best when they were encapsulated in skim milk and held at 4 °C in glass bottles. Skim milk‐encapsulated B longum B6 cells showed a relatively low viability reduction of only 0.15–0.20 log (colony‐forming units (cfu g−1)) after 42 days of storage at 4 °C in glass bottles, regardless of the presence of deoxidant and desiccant. A reduction of 0.38–0.76 log (cfu g−1) was noted for skim milk‐encapsulated cells of B infantis CCRC 14633 under similar storage conditions. Copyright © 2004 Society of Chemical Industry
Atmosphere composition effects on Burlat cherry colour during cold storage
Authors: Remón Sara , Ferrer Ana , López‐Buesa Pascual , Oria Rosa
Published: January 2004

Carbon dioxide‐enriched atmospheres are used to reduce the incidence and severity of cherry decay and to extend postharvest life. Freshly harvested Burlat cherries were placed in jars at 5 °C for 10 days and ventilated with five different atmospheres: (a) air, (b) 12% CO2–4% O2, (c) 12% CO2–20% O2, (d) 5% CO2–4% O2, and (e) 5% CO2–20% O2. Samples were analysed when harvested and after 5 and 10 days of cold storage. Best results were obtained with cherries kept in high‐CO2 atmospheres, independently of O2 concentration. In these conditions the cherries present a higher acidity level (0.65 vs 0.60 g malic acid per 100 ml) and a lower anthocyanin content (0.40 vs 0.48 mg g−1). As a consequence of this, h* (18 vs 20.5) and C* (24 vs 39) values are lower, which makes the cherries visually more reddish and less obscure and therefore more attractive for consumers. In addition, cherries kept in high‐CO2 atmospheres present lower levels of peroxidase (469 vs 737 au g−1) and polyphenoloxidase (73 vs 146 au g−1) activities, which favours postharvest stability of colour. Copyright © 2004 Society of Chemical Industry
The effect of drying temperature on the nutritional quality of New Zealand‐grown maize for growing rats
Authors: James Kerry A C , Butts Christine A , Hardacre Allan K , Koolaard John P , Clark Suzanne M , Scott Margaret F
Published: January 2004

The effect of drying temperature (ambient, 58, 80, 110 °C) on the nutritional quality of grain from two New Zealand maize hybrids (P3476, P3730) grown at two locations (Bay of Plenty, Waikato) was studied in growing rats, and the results of the biological evaluation were compared with the physical properties of the grain. Biological evaluation was carried out using 96 rats, with six rats for each of 16 hybrid × location × drying temperature treatments (three rats per analytical replicate). The experimental diets consisted of 94.5% ground grain supplemented with vitamin and salt mixes. The diets were offered at 15 g day−1 over a 5 day balance period. During the balance period, food intake was recorded and total faeces and urine were collected. The faeces and urine from the three rats of each replicate were pooled, and these samples, together with the diets, were analysed for total nitrogen (N) and gross energy. Dietary intake, faecal and urinary output, nutrient balance and nutrient digestibility and metabolisability were calculated for both N and energy. Before drying, the Waikato grain samples had a higher bulk density and the P3476 samples had a greater hardness. Breakage susceptibility for all samples increased with drying temperature. There were no statistically significant effects of drying temperature on the biological indicators used to assess nutritional quality, despite differences in the physical properties of the grain. There were several significant hybrid × location interactions that could be attributed to the P3730 × Bay of Plenty sample, and these interactions gave significant main effects. The findings suggested that significant savings in drying costs and enhanced productivity from the drying plant could be obtained by the feed grain industry, without compromising the nutritional value of the grain, by increasing the grain drying temperature. Copyright © 2004 Society of Chemical Industry
Lipid classes, fatty acid composition and triacylglycerol molecular species in the kernels of pumpkin (Cucurbita spp) seeds
Authors: Yoshida Hiromi , Shougaki Yumi , Hirakawa Yuki , Tomiyama Yuka , Mizushina Yoshiyuki
Published: January 2004

The lipids extracted from the kernels of pumpkin (Cucurbita spp) seeds of three cultivars were classified by thin layer chromatography into six fractions: steryl esters (SEs, 0.5–1.2%), triacylglycerols (TAGs, 92.7–93.4%), free fatty acids (FFAs, 2.9–3.5%), sn‐1,3‐diacylglycerols (1,3‐DAGs, 0.4–0.9%), sn‐1,2‐diacylglycerols (1,2‐DAGs, 0.7–0.9%) and phospholipids (PLs, 1.5%). Fatty acids derivatised as methyl esters were analysed by gas chromatography with flame ionisation detection. Molecular species and fatty acid distributions of TAGs, isolated from the total lipids in the kernels, were analysed by a combination of argentation thin layer chromatography (TLC) and gas chromatography. A modified argentation TLC procedure, developed to optimise the separation of the complex mixture of total TAGs, provided 11 different groups of TAGs, based on both the degree of unsaturation and the total chain length of fatty acid groups. With a few exceptions, SM2 (5.8–20.1%), S2D (8.8–11.2%), M3 (6.7–24.8%), SMD (6.8–16.7%), M2D (16.7–23.6%), SD2 (4.6–15.1%) and MD2 (4.9–18.6%) were the main TAG components. These results suggest that there are significant differences (P < 0.05) not only in fatty acid distributions of acyl lipids but also in molecular species of TAGs among the three cultivars. The differences in pumpkin cultivars could be appreciable, based on the distribution of molecular species in TAGs. However, pumpkin seed kernels could be utilised successfully as a source of edible oils for human consumption. Copyright © 2004 Society of Chemical Industry
Multivariate classification of Montepulciano d'Abruzzo wine samples according to vintage year
Authors: Giaccio Mario , Del Signore Antonella
Published: January 2004

Samples of Montepulciano wines from three different vintages (1994, 1995 and 1996), produced in different locations in the Abruzzo region of Italy using different yeasts and processing procedures, were subjected to 17 different chemical analyses. The data were analysed by principal component analysis (PCA) and linear discriminant analysis (LDA). From a statistical approach it is possible to point out that vintage year, closely connected with climatic conditions, was the factor that best differentiated wines as regards chemical composition, compared with other factors such as place of origin, type of yeast, fermentation vessel, clarification method and time and temperature of maceration. Copyright © 2004 Society of Chemical Industry
Antioxidant activity of water and alcohol extracts of chamomile flowers, anise seeds and dill seeds
Authors: Mohammad Al‐Ismail Khalid , Aburjai Talal
Published: January 2004

The antioxidant activities of water and alcohol extracts of the flowers of chamomile (Matricaria aurea Schultz) and the seeds of anise (Pimpinella anisum L) and dill (Anethum graveolens L) were investigated. The extracts showed marked antioxidant activity in both linoleic acid and liposome model systems. This indicates that the extracts could be used as antioxidants in fat‐containing foods. The water extracts of chamomile flowers and dill seeds showed higher antioxidant activity than butylated hydroxyanisole, whereas the antioxidant activities of the alcohol extracts of all three plants were lower. The water extracts showed higher antioxidant activity than the corresponding alcohol extracts. The antioxidant activity of both water and alcohol extracts decreased in the order chamomile flowers > gtill seeds > gtnise seeds. The extracts also showed good free radical‐scavenging activity, indicating that they act as hydrogen donors. Copyright © 2004 Society of Chemical Industry
The ratios of degradation characteristics of forages in the rumen of dairy cows: effect of variety and stage of maturity
Authors: Yu P , McKinnon JJ , Christensen DA
Published: January 2004

In situ digestive characteristics of neutral detergent fibre (NDF), non‐fibre carbohydrates (NFC) and crude protein (CP) in alfalfa and timothy were determined in the rumen of dairy cows. Two varieties of alfalfa (Pioneer and Beaver) and timothy (Climax and Joliotte) were grown in western Canada and cut at three maturity stages (alfalfa: 1 = early bud, 2 = late bud, 3 = early bloom; timothy: 1 = joint, 2 = pre – bloom head, 3 = full head). Measured ruminal degradation characteristics were soluble fraction (NFC, CP), undegradable fraction (NDF, CP), lag time (NDF) and rate of degradation of the insoluble but degradable fraction (NDF, NFC, CP). All measured characteristics showed large differences between the two forage species (alfalfa vs timothy) and to a lesser extent between the maturity stages and varieties. Mean total rumen available NDF (248.6 vs 282.5 g kg−1 dry matter (DM)), NFC (200.5 vs 106.1 g kg−1 DM) and CP (139.7 vs 44.5 g kg−1 DM) differed (p < 0.01) between alfalfa and timothy. Based on the measured characteristics, degradation ratios were calculated between total rumen available N and carbohydrates (FN/FCHO), soluble N and carbohydrates (SN/SCHO) and rumen available insoluble N and carbohydrates (EN/ECHO). The ratios showed large differences between the two forages species and to a lesser extent between the varieties and stages of maturity. Alfalfa species had significantly higher (p < 0.01) ratios of FN/FCHO (49.8 vs 18.3 g kg−1), SN/SCHO (115.0 vs 36.1 g kg−1) and EN/ECHO (28.3 vs 12.0 g kg−1) than timothy. These results indicate that alfalfa varieties exhibited a superior rumen fermentation ratio (optimum FN/FCHO = 25–33 g N kg−1 carbohydrates). The results also suggest a potential N loss in alfalfa and N shortage in timothy. Comparing the two varieties of alfalfa, no differences (p > 0.05) were found in the ratios of FN/FCHO and EN/ECHO, but a significant difference (p < 0.05) was found in SN/SCHO (132.3 vs 97.6 g kg−1). However, comparing the two varieties of timothy, there were significant differences (p < 0.01) in FN/FCHO (23.8 vs 12.8 g kg−1) and EN/ECHO (15.3 vs 8.7 g kg−1) ratios but not in SN/SCHO ratio (p > 0.05), indicating large differences between legume and grass. As plant maturity advanced from stage 1 to stage 3, there were no significant changes in all ratios in alfalfa and timothy except the EN/ECHO ratio in timothy (14.3, 13.4 and 8.3 g kg−1 at stages 1, 2 and 3 respectively). It was concluded that the degradation characteristic ratios were dependent on species, variety and/or stage of maturity. Such ratios could be used to optimise a dairy diet composition with regard to rumen fermentation. Copyright © 2004 Society of Chemical Industry
Spaghetti cooking quality of waxy and non‐waxy durum wheats and blends
Authors: Grant Linda A , Doehlert Douglas C , McMullen Michael S , Vignaux Nathalie
Published: January 2004

Quality attributes of waxy durum wheat (Triticum turgidum L), milled semolina and cooked spaghetti were examined and compared with those of two non‐waxy durum cultivars. With the exception of kernel hardness, wheat quality characteristics were similar for both waxy and non‐waxy durum. Compared with average values obtained for durum wheat grown in North Dakota (USA) during the crop year 2000, the values obtained for the wheat used in this study were equal or better for most parameters evaluated. Semolina extraction for all samples was lower than the 2000 average of 62.6%. The waxy lines had higher ash, lower speck count, similar protein quantity, lower wet gluten and stronger mixograph curves than the non‐waxy cultivars. Waxy durum semolina had higher lipid content, starch damage, stirring number and flour swelling values. Spaghetti made from waxy durum semolina had shorter cooking time, similar cooking loss and cooked weight and lower firmness values, which would be unacceptable by most standards. Spaghetti made from blends containing 20–80% waxy durum semolina were evaluated. Cooking time and firmness decreased and cooking loss increased as the amount of waxy semolina increased. Acceptable spaghetti was obtained using 20–40% waxy semolina blends, depending on the quality of the non‐waxy blending material. Copyright © 2004 Society of Chemical Industry
Chemical composition and in vitro digestibility of some Spanish browse plant species
Authors: Ammar Hajer , López Secundino , González Jesús S , Ranilla María J
Published: January 2004

Samples of leaves, flowers and fruits of four browse species were collected from uplands in the province of León (northwestern Spain) at different sampling times (from spring till autumn). The browse species were Erica australis (Spanish heath), Cistus laurifolius (laurel‐leaved rock rose), Quercus pyrenaica (hoary oak) and Rosa canina (wild dog rose). A large variability in chemical composition and in vitro digestibility and gas production kinetics was observed among species and among sampling times within each species. The ranking order of the browse plants according to their in vitro digestibility and gas production kinetics was R canina > Q pyrenaica > C laurifolius > E australis. In the leaves of R canina and Q pyrenaica, crude protein content, digestibility and parameters of gas production tended to decrease throughout the growing season (P < 0.05 in most cases), whereas cell wall contents followed the opposite trend. Seasonal variations were less pronounced in the other browse species. There were significant (P < 0.05) correlations between in vitro digestibility and chemical composition of the browse plants, positive with the crude protein content and negative with the fibre fractions. Copyright © 2004 Society of Chemical Industry
Purification and some properties of a cysteine proteinase from sorghum malt variety SK5912
Authors: Ogbonna Augustine C , Obi Samuel KC , Okolo Bartholomew N , Odibo Frederick JC
Published: January 2004

A cysteine proteinase from sorghum malt variety SK5912 was purified by a combination of 4 M sucrose fractionation, ion‐exchange chromatography on Q‐ and S‐Sepharose (fast flow), gel filtration chromatography on Sephadex G‐100 and hydrophobic interaction chromatography on Phenyl Sepharose CL‐4B. The enzyme was purified 8.4‐fold to give a 13.4% yield relative to the total activity in the crude extract and a final specific activity of 2057.1 U mg−1 protein. SDS—PAGE revealed two migrating protein bands corresponding to apparent relative molecular masses of 55 and 62 kDa, respectively. The enzyme was optimally active at pH 6.0 and 50 °C, not influenced across a relatively broad pH range of 5.0–8.0 and retained over 60% activity at 70 °C after 30‐min incubation. It was highly significantly (P < 0.001) inhibited by Hg2+, appreciably (P < 0.01) inhibited by Ag+, Ba2+ and Pb2+ but highly significantly (P < 0.001) activated by Co2+, Mn2+ and Sr2+. The proteinase was equally highly significantly (P < 0.001) inhibited by both iodoacetate and p‐chloromercuribenzoate and hydrolysed casein to give the following kinetic constants: Km = 0.33 mg ml−1; Vmax = 0.08 µmol ml−1 min−1. Copyright © 2004 Society of Chemical Industry
Headspace solid‐phase microextraction for characterization of fragrances of lemon verbena (Aloysia triphylla) by gas chromatography‐mass spectrometry
Authors: Kim Nam‐Sun , Lee Dong‐Sun
Published: January 2004

Natural fragrances from lemon verbena (Aloysia triphylla) were studied by headspace solid phase microextraction (HS‐SPME) techniques followed by gas chromatography‐mass spectrometry (GC‐MS), with six different fibre coatings being tested to evaluate the extraction efficiencies of several selected compounds. A total of 14 compounds were identified in the fragrances of lemon verbena. Geranial and neral were detected as major components and α‐pinene, β‐pinene, β‐caryophyllene, and curcumene as minor components. Enantiomeric analysis of chiral compounds from lemon verbena was carried out on a chiral column. α‐Pinene, limonene, and camphor in the fragrances emitted from lemon verbena were found in the (+), (–), and (–) forms, respectively.
Validation of a thermal decomposition mechanism of formaldehyde by detection of CH2O and HCO behind shock waves
Authors: Friedrichs Gernot , Davidson David F. , Hanson Ronald K.
Published: January 2004

The thermal decomposition of formaldehyde was investigated behind shock waves at temperatures between 1675 and 2080 K. Quantitative concentration time profiles of formaldehyde and formyl radicals were measured by means of sensitive 174 nm VUV absorption (CH2O) and 614 nm FM spectroscopy (HCO), respectively. The rate constant of the radical forming channel (1a), CH2O + M → HCO + H + M, of the unimolecular decomposition of formaldehyde in argon was measured at temperatures from 1675 to 2080 K at an average total pressure of 1.2 bar, k1a = 5.0 × 1015 exp(‐308 kJ mol−1/RT) cm3 mol−1 s−1. The pressure dependence, the rate of the competing molecular channel (1b), CH2O + M → H2 + CO + M, and the branching fraction β = k1a/(kA1a + k1b) was characterized by a two‐channel RRKM/master equation analysis. With channel (1b) being the main channel at low pressures, the branching fraction was found to switch from channel (1b) to channel (1a) at moderate pressures of 1–50 bar. Taking advantage of the results of two preceding publications, a decomposition mechanism with six reactions is recommended, which was validated by measured formyl radical profiles and numerous literature experimental observations. The mechanism is capable of a reliable prediction of almost all formaldehyde pyrolysis literature data, including CH2O, CO, and H atom measurements at temperatures of 1200–3200 K, with mixtures of 7 ppm to 5% formaldehyde, and pressures up to 15 bar. Some evidence was found for a self‐reaction of two CH2O molecules. At high initial CH2O mole fractions the reverse of reaction (6), CH2OH + HCO ⇌ CH2O + CH2O becomes noticeable. The rate of the forward reaction was roughly measured to be k6 = 1.5 × 1013 cm3 mol−1 s−1. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 157–169 2004
Kinetics and mechanism of the catalytic dehydration of HCO3− by zinc(II) complexes of tripod ligands
Authors: Ge Qingchun , Guo Yanhe , Lin Hai , Lin Huakuan , Zhu Shourong
Published: January 2004

The kinetics of the catalyzed dehydration of HCO3− by zinc(II) containing tripod complexes has been studied at 25°C using the stopped‐flow technique. The direction of reaction curve was changed in aqueous solution when the pH of the solution was greater than 7.5. The pH‐profile of rates of the dehydration reactions indicates that only the aqua complex catalyzes the dehydration of HCO3− via a ligand substitution process. The second‐order rate constants for the dehydration of HCO3− catalyzed by complexes Zn3L1, Zn3L2, Zn3L3, and Zn3L4 are 0.96, 2.53, 12.05, and 6.99 mol−1 dm3 s−1 respectively. At the same time, the pKa values 7.60, 7.16, 7.51, and 7.42 for the deprotonation of the Zn(II)‐bound water in the four catalysts were obtained, which are consistent with those that resulted from pH titrations, i.e. 7.47, 7.25, 7.52, and 7.38 respectively. The mechanism is proposed and the results are compared with other model complexes of carbonic anhydrase. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 197–203, 2004
Behavioral model of a noisy VCO for efficient time‐domain simulation
Authors: Centurelli Francesco , Ercolani Alessandro , Scotti Giuseppe , Tommasino Pasquale , Trifiletti Alessandro
Published: January 2004

In this paper, a behavioral model of a noisy oscillator, which allows system simulation with CAD tools and implementation in hardware description languages, is presented. A procedure to extract the parameters of the empirical model from noise measurements, performed by means of a circuit simulator, has been proposed and successfully applied. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 352–355, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11379
Design of multiple U‐shaped slot microstrip patch antenna in Hiper‐LAN band
Authors: Jeong GyeyTeak , Yoon Joong‐Han , Lee Sang Mok , Kwak Kyung‐Sup
Published: January 2004

In this paper, a multiple U‐shaped slot antenna is described, designed, fabricated, and measured for Hiper‐LAN. The design is based on a U‐shaped slot and two inverted U‐shaped slots. To obtain sufficient bandwidth, a foam layer is inserted between the ground plane and substrate. A measured impedance bandwidth approximately 400 MHz or about 7.6% (VSWR ≤ 1.5) referenced to the center frequency is obtained. The gain is measured at 5.43–4.45 dBi. The experimental far‐field patterns are shown to be broad across the pass band, with the 3‐dB beam width in azimuth and elevation at 58.17° and 66.57°, respectively. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 368–370, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11384
Mutual coupling between spherical‐rectangular microstrip antennas
Authors: Burum Niksa , Sipus Zvonimir , Bartolic Juraj
Published: January 2004

The mutual coupling between rectangular microstrip patches mounted on a spherical structure is studied in this paper. The analysis approach is based on the spectral‐domain method of moments (MoM). An approximate method is developed to calculate coupling between currents located on different patches. A laboratory model is built to test different configurations of patches and to validate the calculated results. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 387–391, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11389
Tunable dual‐wavelength linear‐cavity fiber laser by using an external injection‐seeding scheme
Authors: Peng Peng‐Chun , Chi Sien
Published: January 2004

In this paper, we propose and demonstrate a tunable dual‐wavelength fiber laser by using an external injection‐seeding scheme with a Fabry–Perot laser diode. The wavelength tuning range of this tunable dual‐wavelength fiber laser is 12.6 nm, and the optical side‐mode suppression ratio (SMSR) is more than 27 dB. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 406–408, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11394
Analytical noise model of a high‐electron‐mobility transistor for microwave‐frequency application
Authors: Guru Vandana , Vyas H. P. , Gupta Mridula , Gupta R. S.
Published: January 2004

Noise analysis for AlGaAs/GaAs HEMT and AlGaAs/InGaAs/GaAs PHEMT is developed at microwave frequency using an accurate charge control approach. The small‐signal parameters and the drain and gate‐noise sources are calculated to determine the noise coefficients and correlation coefficients. Finally, the minimum noise figure is evaluated by incorporating the extrinsic noise sources and compared with the experimental data, which is in excellent agreement. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 410–417, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11396
A low‐pass filter of wide stopband with a novel multilayer fractal photonic bandgap structure
Authors: Liu Hai‐Wen , Sun Xiao‐Wei , Li Zheng‐Fan
Published: January 2004

A novel multilayer fractal photonic bandgap (PBG) is presented as the substrate for a microstrip line and resulting configuration builds a low‐pass filter (LPF) of wide stop‐band. Experimental results in comparison with the corresponding two filters with monoplayer PBG show that the proposed filter drastically enhances the width of the stop‐band. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 431–432, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11401
Semiconductor optical amplifier cascaded optical single‐sideband modulation with phase pre‐distortion
Authors: Koo Bon‐Jo , Lee Ui‐Soo , Lee Seok , Han Sang‐Kook
Published: January 2004

An optical single sideband modulation with a cascaded semiconductor optical amplifier (SOA) is proposed and experimentally demonstrated. The single sideband‐modulated signal is predicted using the phase predistortion technique in the RF input of the Mach–Zehnder modulator. The predicted results are compared with the measured data and good agreement is reported. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 436–438, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11403
Molecular cloning and expression analysis of vitellogenin in scallop, Patinopecten yessoensis (bivalvia, mollusca)
Authors: Osada Makoto , Harata Masahiko , Kishida Mitsuyo , Kijima Akihiro
Published: January 2004

The present study was undertaken to determine scallop vitellogenin (Vtg) cDNA sequence, to identify Vtg synthesizing cell, and to analyze the regulation of Vtg mRNA expression. Clones containing partial cDNA sequence of Vtg were isolated from cDNA library of the scallop ovary by immunoscreening with the anti‐scallop vitellin (Vn) serum. The deduced amino acid sequence of the clone containing the longest cDNA insert (1,689 bp) was identified as a member of the lipid transport protein family and exhibited about 20–35% identity with Vtgs of other oviparous animals. Northern blot analysis identified a single transcript longer than 10 kb in the ovary. Dot blot analysis of the ovary showed a high amount of Vtg mRNA during the growing stage and the level was retained until spawning stage. In situ hybridization demonstrated the expression of Vtg mRNA in the auxiliary cells closely associated with growing oocytes, suggesting that the synthesis of a major yolk protein in the scallop occurs through hetero‐synthetic pathway without mediation through the blood flow but occurs de novo in the ovary. The content of Vtg mRNA in the ovarian tissue cultured in vitro with vitellogenesis promoting factor (VPF), which strongly promotes Vtg protein synthesis, from the cerebral plus pedal ganglion (CPG) showed no change. The transcription of Vtg mRNA appeared to be promoted by estradiol‐17β (E2) not by VPF although VPF may enhance the translation of Vtg mRNA. Mol. Reprod. Dev. 67: 273–281, 2004. © 2004 Wiley‐Liss, Inc.
Study of newly synthesized proteins during bovine oocyte maturation in vitro using image analysis of two‐dimensional gel electrophoresis
Authors: Coenen Karine , Massicotte Lyne , Sirard Marc‐André
Published: January 2004

To investigate protein synthesis during bovine oocyte maturation in vitro, oocytes were put in culture with 35S‐methionine for 4 hr periods from time zero to 28 hr. Pools of 10 oocytes were then prepared for two‐dimensional gel electrophoresis (2‐DE). For each time interval, three gels were obtained, digitalized, and analyzed to detect proteins. Then, the gel containing the most proteins was chosen as the reference gel and compared with the others. An averaged gel was created with proteins present in at least two gels of the three. Our results indicate that the rate of protein synthesis is higher at the beginning of maturation until the appearance of metaphase I (MI, 8–12 hr) and then it decreases and stays relatively constant. Percentages of initial proteins (0–4 hr) and remaining present during the progression decrease progressively from 100% to 53%. In contrast, when we compare proteins synthesized from the 4 to 8 hr period with proteins from the 8 to 12 or the 12 to 16 hr intervals, percentages of overall protein matching are stable with values of 81 and 79%, respectively. Comparison of proteins from 20 to 24 hr with proteins from 16 to 20 or 24 to 28 hr intervals also gives stable percentages of overall protein matching with values of 83 and 84%, respectively. Furthermore, a higher number of new proteins is observed at 4–8 hr (n = 130) and 16–20 hr (n = 136) of maturation. Thus, three major patterns of protein synthesis were observed during bovine oocyte maturation in vitro: one at the beginning of maturation (0–4 hr), another one in the middle (4–16 hr), and the last one after the completion of MI stage (16–28 hr). Mol. Reprod. Dev. 67: 313–322, 2004. © 2004 Wiley‐Liss, Inc.
MAP kinases regulate unfertilized egg apoptosis and fertilization suppresses death via Ca2+ signaling
Authors: Sadler Kirsten C. , Yüce Özlem , Hamaratoǧlu Fisun , Vergé Valérie , Peaucellier Gérard , Picard André
Published: January 2004

The default fate for eggs from many species is death by apoptosis and thus, successful fertilization depends upon suppression of the maternal death program. Little is known about the molecular triggers which activate this process or how the fertilization signal suppresses the default maternal apoptotic pathway. The MAP kinase (MAPK) family member, ERK, plays a universal and critical role in several stages of oocyte meiotic maturation, and fertilization results in ERK inactivation. In somatic cells, ERK and other MAPK family members, p38 and JNK, provide opposing signals to regulate apoptosis, however, it is not known whether MAPKs play a regulatory role in egg apoptosis, nor whether suppression of apoptosis by fertilization is mediated by MAPK activity. Here we demonstrate that MAPKs are involved in starfish egg apoptosis and we investigate the relationship between the fertilization induced signaling pathway and MAPK activation. ERK is active in post‐meiotic eggs just until apoptosis onset and then p38, JNK and a third kinase are activated, and remain active through execution. Sequential activation of ERK and p38 is necessary for apoptosis, and newly synthesized proteins are required both upstream of ERK and downstream of p38 for activation of the full apoptotic program. Fertilization causes a dramatic rise in intracellular Ca2+, and we report that Ca2+ provides a necessary and sufficient pro‐survival signal. The Ca2+ pathway following fertilization of both young and aged eggs causes ERK to be rapidly inactivated, but fertilization cannot rescue aged eggs from death, indicating that ERK inactivation is not sufficient to suppress apoptosis. Mol. Reprod. Dev. 67: 366–000, 2004. © 2004 Wiley‐Liss, Inc.
Process for the integrated extraction, identification and quantification of metabolites, proteins and RNA to reveal their co‐regulation in biochemical networks
Authors: Weckwerth Wolfram , Wenzel Kathrin , Fiehn Oliver
Published: January 2004

A novel extraction protocol is described with which metabolites, proteins and RNA are sequentially extracted from the same sample, thereby providing a convenient procedure for the analysis of replicates as well as exploiting the inherent biological variation of independent samples for multivariate data analysis. A detection of 652 metabolites, 297 proteins and clear RNA bands in a single Arabidopsis thaliana leaf sample was validated by analysis with gas chromatography coupled to a time of flight mass spectrometer for metabolites, two‐dimensional liquid chromatography coupled to mass spectrometry for proteins, and Northern blot analysis for RNA. A subset of the most abundant proteins and metabolites from replicate analysis of different Arabidopsis accessions was merged to form an integrative dataset allowing both classification of different genotypes and the unbiased analysis of the hierarchical organization of proteins and metabolites within a real biochemical network.
Proteomic analysis of nuclear proteins from proliferative and differentiated human colonic intestinal epithelial cells
Authors: Turck Natacha , Richert Sophie , Gendry Patrick , Stutzmann Jeanne , Kedinger Michèle , Leize Emmanuelle , Simon‐Assmann Patricia , Van Dorsselaer Alain , Launay Jean‐François
Published: January 2004

Self‐renewing tissues such as the intestine contain progenitor proliferating cells which subsequently differentiate. Cell proliferation and differentiation involve gene regulation processes which take place in the nucleus. A human intestinal epithelial cell line model (Caco2/TC7) which reproduces these dynamic processes has been used to perform proteomic studies on nuclear proteins. Nuclei from Caco2/TC7 cells at proliferative and differentiated stages were purified by subcellular fractionation. After two‐dimensional gel electrophoresis separation and ruthenium staining, 400 protein spots were detected by image analysis. Eighty‐five spots corresponding to 60 different proteins were identified by matrix‐assisted laser desorption/ionization mass spectrometry in nuclei from proliferative cells. Comparison of nuclear proteomes from proliferative or differentiated cells by differential display resulted in the identification of differentially expressed proteins such as nucleolin, hnRNP A2/B1 and hnRNP A1. By using Western blot analysis, we found that the expression and number of specific isoforms of these nuclear proteins decreased in differentiated cells. Immunocytochemistry experiments also showed that in proliferative cells nucleolin was distributed in nucleoli‐like bodies. In contrast, hnRNPs A2/B1 and A1 were dispersed throughout the nucleus. This study of the nuclear proteome from intestinal epithelial cells represents the first step towards the establishment of a protein database which will be a valuable resource in future studies on the differential expression of nuclear proteins in response to physiological, pharmacological and pathological modulations.
Mining biomarkers in human sera using proteomic tools
Authors: Zhang Rulin , Barker Lisa , Pinchev Deborah , Marshall John , Rasamoelisolo Michèle , Smith Chris , Kupchak Peter , Kireeva Inga , Ingratta Leslee , Jackowski George
Published: January 2004

One of the major difficulties in mining low abundance biomarkers from serum or plasma is due to the fact that a small number of proteins such as albumin, α2‐macroglobulin, transferrin, and immunoglobulins, may represent as much as 80% of the total serum protein. The large quantity of these proteins makes it difficult to identify low abundance proteins in serum using traditional 2‐dimensional electrophoresis. We recently used a combination of multidimensional liquid chromatography and gel electrophoresis coupled to matrix‐assisted laser desorption/ionization‐quadrupole‐time of flight and Ion Trap liquid chromatography‐tandem mass spectrometry to identify protein markers in sera of Alzheimer's disease (AD), insulin resistance/type‐2 diabetes (IR/D2), and congestive heart failure (CHF) patients. We identified 8 proteins that exhibit higher levels in control sera and 36 proteins that exhibit higher levels in disease sera. For example, haptoglobin and hemoglobin are elevated in sera of AD, IR/D2, and CHF patients. The levels of several other proteins including fibrinogen and its fragments, alpha 2‐macroglobulin, transthyretin, pro‐platelet basic protein, protease inhibitors clade A and C, as well as proteins involved in the classical complement pathway such as complement C3, C4, and C1 inhibitor, were found to differ between IR/D2 and control sera. The sera levels of proteins, such as the 10 kDa subunit of vitronectin, alpha 1‐acid glycoprotein, apolipoprotein B100, fragment of factor H, and histidine‐rich glycoprotein were observed to be different between AD and controls. The differences observed in these biomarker candidates were confirmed by Western blot and the enzyme‐linked immunosorbent assay. The biological meaning of the proteomic changes in the disease states and the potential use of these changes as diagnostic tools or for therapeutic intervention will be discussed.
Environmental stress responses in Lactobacillus: A review
Authors: De Angelis Maria , Gobbetti Marco
Published: January 2004

Environmental stress responses in Lactobacillus, which have been investigated mainly by proteomics approaches, are reviewed. The physiological and molecular mechanisms of responses to heat, cold, acid, osmotic, oxygen, high pressure and starvation stresses are described. Specific examples of the repercussions of these effects in food processing are given. Molecular mechanisms of stress responses in lactobacilli and other bacteria are compared.
Grape berry biochemistry revisited upon proteomic analysis of the mesocarp
Authors: Sarry Jean‐Emmanuel , Sommerer Nicolas , Sauvage François‐Xavier , Bergoin Alexis , Rossignol Michel , Albagnac Guy , Romieu Charles
Published: January 2004

Major soluble proteins of grapevine ripe berries were extracted from six different cultivars including non vinifera, with trichloroacetic acid acetone and resolved in two‐dimensional electrophoresis (2‐DE) gels. About three hundred spots were detected on the 2‐DE map after colloidal blue staining. From 2‐DE map of cv. Gamay mesocarp, 67 proteins were identified (p > 0.95) using matrix‐assisted laser desorption/ionization‐mass spectrometry analysis. About 34%, 19%, and 13% of identified proteins play, respectively, a role in energy metabolism, defense, and stress response and primary metabolism. 2‐DE analysis revealed considerable accumulation of dehydrin, invertase, and a putative transcription factor in the ripe fruit, in addition to pathogenesis‐related proteins such as chitinase and thaumatin‐like proteins previously documented as prevalent proteins in ripe berries. Actual translation of redundant transcripts of unclear function such as Grip31, Grip32, and Grip61 recently cloned in ripe grape berries was confirmed. The relative abundance of UDP‐glucose pyrophosphorylase and vacuolar invertase strongly supported a key role of the apoplastic pathway of sugar loading during ripening. Comparative analysis shows that differences between cultivars were low, but different isoforms of alcohol dehydrogenase and of a transcription factor of hexose transporter were obvious in the six cultivars. Peptide mass fingerprinting suggests that the Adh isoforms would be Adh2/Adh6 or Adh2/Adh7 dimers and unambiguously shows that considerable deletion/insertion inside Adh7 are not cloning artifacts.
Comparing expression level‐dependent features in codon usage with protein abundance: An analysis of ‘predictive proteomics’
Authors: McHardy Alice C. , Pühler Alfred , Kalinowski Jörn , Meyer Folker
Published: January 2004

Synonymous codon usage is a commonly used means for estimating gene expression levels of Escherichia coli genes and has also been used for predicting highly expressed genes for a number of prokaryotic genomes. By comparison of expression level‐dependent features in codon usage with protein abundance data from two proteome studies of exponentially growing E. coli and Bacillus subtilis cells, we try to evaluate whether the implicit assumption of this approach can be confirmed with experimental data. Log‐odds ratio scores are used to model differences in codon usage between highly expressed genes and genomic average. Using these, the strength and significance of expression level‐dependent features in codon usage were determined for the genes of the Escherichia coli, Bacillus subtilis and Haemophilus influenzae genomes. The comparison of codon usage features with protein abundance data confirmed a relationship between these to be present, although exceptions to this, possibly related to functional context, were found. For species with expression level‐dependent features in their codon usage, the applied methodology could be used to improve in silico simulations of the outcome of two‐dimensional gel electrophoretic experiments.
Proteome analysis of cultivar‐specific deregulations of Oryza sativa indica and O. sativa japonica cellular suspensions undergoing Rice yellow mottle virus infection
Authors: Ventelon‐Debout Marjolaine , Delalande François , Brizard Jean‐Paul , Diemer Hélène , Van Dorsselaer Alain , Brugidou Christophe
Published: January 2004

We have used two‐dimensional gel electrophoresis with mass spectrometry analysis to study the temporal patterns of protein expression during RYMV (Rice yellow mottle virus) infection in rice cells of two cultivars: IR64, Oryza sativa indica, susceptible, and Azucena, O. sativa japonica, partially resistant to RYMV. Proteomic analysis of nonstressed and RYMV inoculated cells showed statistically significant changes in the relative levels of 40 IR64 proteins and 24 Azucena proteins. Protein identification using mass spectrometry was attempted for all the differentially regulated proteins. This global analysis detected 32 hypothetical “new” proteins. Nineteen differentially regulated proteins were identified for IR64 cultivar, while 13 were identified for Azucena cultivar, including proteins in three functional categories: metabolism, stress‐related proteins, and translation. These data revealed that a number of proteins regulated by abiotic stress response pathway were activated by RYMV in both cultivars (such as salt‐induced protein, heat shock proteins (HSPs), superoxide dismutase (SOD), and others have functions consistent with the susceptibility or partially resistance trait (such as dehydrin, proteins involved in glycolysis pathway).
Differentiation between peptides containing acetylated or tri‐methylated lysines by mass spectrometry: An application for determining lysine 9 acetylation and methylation of histone H3
Authors: Zhang Kangling , Yau Peter M. , Chandrasekhar Bhaskar , New Ron , Kondrat Richard , Imai Brian S. , Bradbury Morton E.
Published: January 2004

Histone acetylation and methylation play a critical role in transcription and gene regulation. Identification of sites of lysine acetylation and methylation in histones or other proteins by mass spectrometry (MS) is of increasing interest. In this paper, we report the use of MS to differentiate between peptides containing acetylated or tri‐methylated lysines. High accuracy matrix‐assisted laser desorption/ionization‐time of flight MS gives better than five parts per million measurement accuracy, which is sufficient to verify acetylation and/or methylation. Electrospray ionization tandem mass spectrometry was used to assign modification sites and to differentiate acetylation from methylation. Typically, an immonium ion at m/z 98 corresponds to a mono‐methylated lysine and an immonium ion at m/z 126 corresponds to an acetylated lysine. The neutral loss ion (MH+‐59) is unique for a tri‐methylated lysine. For a peptide with two or more modification sites of acetylation or tri‐methylation or one site containing partial acetylation and tri‐methylation, the a2‐, b2‐type ion is the characteristic index for an acetylated lysine whereas the b2‐59 ion is indicative of a tri‐methylated lysine in the N‐terminus. The y‐type ions and y‐59 ions are charateristic of an acetylated lysine and a tri‐methylated lysine at the C‐terminus, respectively. We demonstrated that a lysine in a peptide modified by methylation or acetylation can be differentiated by MS using our method. Even if more then one lysine is present in a peptide and different modifications of this amino acid occur, they can be distinguished. This method was successful for the determination of the acetylation and methylation status of lysine 9 of histone H3 in chicken erythrocytes and human HeLa cell lines.
An analysis of the proteomic profile for Thermoanaerobacter tengcongensis under optimal culture conditions
Authors: Wang Jingqiang , Xue Yanfen , Feng Xiaoli , Li Xiaolei , Wang Hao , Li Wei , Zhao Caifeng , Cheng Xiaojie , Ma Yanhe , Zhou Peijin , Yin Jianning , Bhatnagar Aruni , Wang Rong , Liu Siqi
Published: January 2004

The genome of Thermoanaerobacter tengcongensis is estimated to encode 2588 theoretical proteins. In this study, we have vitalized approximately 46% of the theoretical proteome experimentally using a proteomic strategy that combines three different methods, shotgun digestion plus high‐performance liquid chromatography (HPLC) with ion‐trap tandem mass spectrometry (shotgun‐liquid chromatography (LC)/MS), one‐dimensional sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) plus HPLC with ion‐trap tandem mass spectrometry (one‐dimensional electrophoresis (1DE)‐LC/MS), and two‐dimensional gel electrophoresis plus matrix‐assisted laser desorption/ionization‐time of flight‐mass spectrometry (2DE‐MALDI‐TOF‐MS). Of the 1200 proteins identified, as few as 76 proteins were globally found by all three approaches, and notably, most of these proteins were in the soluble fraction. However, there were a number of unique proteins detected by one method only, suggesting that our strategy provides a means toward obtaining a comprehensive view of protein expression profile. Proteins from the major metabolic pathways are strongly represented on the map, and a number of these enzymes were identified by more than one proteomic method. Based upon the proteins identified in the present study, we are able to broaden the understanding of how T. tengcongensis survives under high temperature environment, whereas several of its properties can not be fully explained by genome data.