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101.
Alterations in microbial culture conditions may trigger the production of diverse bioactive secondary metabolites. While applying various culture conditions and monitoring secondary metabolite profiles using LC/MS, hormaomycins B and C (1 and 2) were discovered from a marine mudflat-derived actinomycete, Streptomyces sp., collected in Mohang, Korea. The planar structures of the hormaomycins, which bear structurally-unique units, such as 4-(Z)-propenylproline, 3-(2-nitrocyclopropyl)alanine, 5-chloro-1-hydroxypyrrol-2-carboxylic acid and β-methylphenylalanine, were established as the first natural analogues belonging to the hormaomycin peptide class. The absolute configurations of 1 and 2 were deduced by comparing their CD spectra with that of hormaomycin. These hormaomycins exhibited significant inhibitory effects against various pathogenic Gram-positive and Gram-negative bacteria. 相似文献
102.
Budong Qian Reinder De Jong Richard Warren Aston Chipanshi Harvey Hill 《Agricultural and Forest Meteorology》2009,149(6-7):1022-1031
A study to forecast regional spring wheat (Triticum aestivum L.) yields on the Canadian Prairies was conducted, based on simulated daily water use and soil water contents derived from the National Drought Model. Empirical linear regression models were calibrated from 1976 to 2006 spring wheat yield data for this purpose. Potential predictors assessed were mainly those indicators related to water stress conditions at different crop growth stages. Stepwise regression and cross-validation were employed for the selection of the predictors in multivariate linear regression models used for forecasting spring wheat yields from seeding to harvest. The cross-validated “forecasts” for 1976–2006, using data up to harvest, explained 77%, 64%, 63% and 70% of yield variances, respectively, for Alberta, Saskatchewan, Manitoba and the entire Prairie region. Root mean squared error of the “forecasts” ranged from 8% to 11% of the average yields. The prediction accuracy earlier in the season was often lower than later in the season. Usable prediction accuracy was found by the middle of the growing season (around heading or anthesis), but only marginally effective at seeding time, especially so for Saskatchewan. 相似文献
103.
Hak Jin Kim Yong Woo Kim In Sook Lee Jong Woon Song Yeon Joo Jeong Seon Hee Choi Kyung Un Choi Kuen Tak Suh Byung Mann Cho 《Acta veterinaria Scandinavica》2009,51(1):30
Background
To test the hypothesis that triolein emulsion will increase vascular permeability of skeletal muscle.Methods
Triolein emulsion was infused into the superficial femoral artery in rabbits (triolein group, n = 12). As a control, saline was infused (saline group, n = 18). Pre- and post-contrast T1-weighted MR images were obtained two hours after infusion. The MR images were qualitatively and quantitatively evaluated by assessing the contrast enhancement of the ipsilateral muscles. Histologic examination was performed in all rabbits.Results
The ipsilateral muscles of the rabbits in the triolein group showed contrast enhancement, as opposed to in the ipsilateral muscles of the rabbits in the saline group. The contrast enhancement of the lesions was statistically significant (p < 0.001). Histologic findings showed that most examination areas of the triolein and saline groups had a normal appearance.Conclusion
Rabbit thigh muscle revealed significantly increased vascular permeability with triolein emulsion; this was clearly demonstrated on the postcontrast MR images. 相似文献104.
Marian E.H. Bos Mirjam Nielen Guus Koch Annemarie Bouma Mart C.M. De Jong Arjan Stegeman 《Preventive veterinary medicine》2009,88(4):278-285
To optimize control of an avian influenza outbreak knowledge of within-flock transmission is needed. This study used field data to estimate the transmission rate parameter (β) and the influence of risk factors on within-flock transmission of highly pathogenic avian influenza (HPAI) H7N7 virus in the 2003 epidemic in The Netherlands. The estimation is based on back-calculation of daily mortality data to fit a susceptible-infectious-dead format, and these data were analysed with a generalized linear model. This back-calculation method took into account the uncertainty of the length of the latent period, the survival of an infection by some birds and the influence of farm characteristics. After analysing the fit of the different databases created by back-calculation, it could be concluded that an absence of the latency period provided the best fit. The transmission rate parameter (β) from these field data was estimated at 4.50 per infectious chicken per day (95% CI: 2.68–7.57), which was lower than what was reported from experimental data. In contrast to general belief, none of the studied risk factors (housing system, flock size, species, age of the birds in weeks and date of depopulation) had significant influence on the estimated β. 相似文献
105.
Sung-Hoon Park Noton Kumar Dutta Min-Won Baek Dong-Jae Kim Yi-Rang Na Seung-Hyeok Seok Byoung-Hee Lee Ji-Eun Cho Geon-Sik Cho Jae-Hak Park 《Journal of veterinary science (Suw?n-si, Korea)》2009,10(2):141-146
The effect of NaCl plus 3% chitosan on the systolic blood pressure of spontaneously hypertensive rats (SHR) were evaluated and compared with NaCl plus KCl (NaCl, 49.36% + KCl 49.36%) and chitosan or NaCl treatment alone. In SHR, administration of NaCl plus chitosan (44 mM Na/day) for two months significantly decreased the systolic blood pressure greater than of NaCl plus KCl and NaCl alone. NaCl plus chitosan resulted, though not statistically significant, in decreased urinary Na+ excretion and decreased blood urea nitrogen levels. Urinary creatinine of NaCl plus chitosan was slightly decreased compared to 3 treated groups. Serum electrolytes levels, however, remained unchanged. The combination of NaCl and chitosan may be superior to the conventional use of NaCl plus KCl or NaCl alone in the prevention of hypertension. Even though these supplementary diets have demonstrated potential anti-hypertensive effects in the experimental animal model, further research is needed before any recommendations can be made. 相似文献
106.
Verticillium wilt (VW) is one of the important yield-limiting diseases for potato production. To develop resistant clones, the potential for early generation selection was studied using three basic selection methods, individual, family, and within family selection, for two clonal generations. A total of 152 clones were derived from four cross types (2x × 2x, 2x × 4x, 4x × 2x and 4x × 4x). Clones were evaluated for maturity, symptom expression, yield and stem colonization in replicated trials. Heritability and selection response for the traits were estimated for each selection method. Direct selection in the second clonal generation and individual selection showed more gain than that from other methods. Both 2x × 2x and 4x × 2x families were higher yielding and had lower stem colonization scores than 2x × 4x and 4x × 4x crosses. Therefore, 2x × 2x or 4x × 2x crosses between carefully chosen parents with high yield and VW resistance may produce offspring with superior performance. 相似文献
107.
Md Romij Uddin Leonard John Wade Jong Yeong Pyon Md Abdul Mazid 《Journal of Crop Science and Biotechnology》2009,12(1):17-23
An experiment was carried out at the Agronomy Field Laboratory, Bangladesh Agricultural University (BAU), Mymensingh in Old
Brahmaputra Alluvial Flood Plain (AEZ-9) during December 2005 to May 2006 to examine the root growth of different rice cultivars
under various establishment methods. This experiment comprised two sets of treatment (i) three methods of planting viz., dry
direct seeding, wet direct seeding and transplanting, and (ii) six rice cultivars, two inbreds viz., BRRI Dhan 28 and BRRI
Dhan 29, two hybrids, viz., Aalok 6201 and Sonarbangla 1 and two local improved cultivar viz., Habigonj IV and Habigonj VIII.
Cultivars had more remarkable effect on different root parameters i.e. number of roots, root length, root length density,
root biomass, root weight ratio and root shoot ratio of hybrid, inbred and local improved rice cultivars than method of planting.
BRRI Dhan 28 performed the best for most of the parameters. At harvest, BRRI Dhan 29 showed the best rooting behavior among
the cultivars. For both stages hybrid rice cultivars showed intermediate and local improved cultivars performed lower in rooting
behavior. Direct seeding method performed better than transplanting method for most of the root parameters but wet direct
seeding and dry direct seeding methods were identical. Interaction effect between method of planting and cultivar in most
of the root parameters were insignificant. But, BRRI Dhan 28 and BRRI Dhan 29 under wet direct seeding method and Sonarbanngla
1 under transplanting method showed the best rooting performance among the other combinations. 相似文献
108.
In Seong Choi Seung Gon Wi Se Ra Jung Darshan H. Patel Hyeun-Jong Bae 《Journal of Wood Science》2009,55(5):329-334
β-Glucosidase (β-1,4-D-glucoside glucohydrolase: EC.3.2.1.21) catalyzes the hydrolysis of β-glucosidic bonds between saccharides
and aryl or alkyl groups. A gene encoding β-glucosidase from Bacillus licheniformis KCTC 1918, an anaerobic spore-forming soil bacterium, was cloned and characterized. The structural gene for the β-glucosidase
consists of 1410 bp encoding 469 amino acid residues, and has a molecular weight of 53.4 kDa as estimated by sodium dodecyl
sulfate polyacrylamide gel electrophoresis with 12% separating gel. The enzyme activity was determined against pNPG as a substrate. The enzyme was optimally active at pH 6.0 (citrate-phosphate buffer) and 47°C. β-Glucosidase retained
100% of its original activity for 24 h. The activity of the enzyme was stimulated by glycerol and urea and was decreased by
Ca2+, Cu2+, Hg2+, Mg2+, and Mn2+. In particular, Cu2+ had the strongest negative effect on β-glucosidase activity. The purified β-glucosidase was active against pNPG and cellobiose. When the β-glucosidase was tested for cellulose hydrolysis, the supplement of β-glucosidase with cellulose
increased the glucose yield from pine wood powder by 139.8%. 相似文献
109.
Kim DK Jeong SC Gorinstein S Chon SU 《Plant foods for human nutrition (Dordrecht, Netherlands)》2012,67(1):71-75
The aim of this investigation was to evaluate the biological, alcohol dehydrogenase (ADH) and antiproliferative activities
of different extracts of mungbean seeds and sprouts. All extracts from the sprouts showed higher contents of total phenolics
(TP), total flavonoids (TF), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity than from seeds. The highest
DPPH and tyrosinase inhibition activities were registered in ethyl acetate (EtOAc) extract. ADH activity of methanol (MeOH),
n-hexane (n-hexane) and n-butanol (n-BuOH) extracts from sprouts was significantly higher (P < 0.05) than from seeds. However, the highest ADH activity was found in water extract of seeds. According to 3-(4, 5-dimethylthiazol
-2-yl)-2, 5-diphenyltetrazolium bromide) (MTT) assay, extracts from sprouts were more effective against Calu-6 (human pulmonary
carcinoma) and SNU-601 (human gastric carcinoma) cells than from seeds. EtOAc extract showed the highest antiproliferative
activity in both sprouts and seeds, followed by n-hexane extraction. During sprouting of mungbean, all the studied components
significantly increased. In conclusion, the extracts of sprouts are more effective than from seeds and could be a potential
source of antioxidants linked with health benefits. 相似文献
110.
The dynamics of the friction yarn formation process is described in terms of the dynamic behavior of the process state variables.
Production efficiency and product quality of friction spinning are influenced by these process state variables. This study
was performed with the intention of setting up a dynamic model based on mass balance in order to delineate the dynamic behavior
of the cross-sectional area of the in-process bundle on the friction drum surface and to attain the distribution profiles
of the cross-sectional area in transient state and in steady state as well. Then, simulation results were compared with those
of the experiment, while the input variation was used as a test signal. Theoretical model shows that the bundle thickness
on the friction drum has the dynamic characteristics of an integrating system with interval due to the finite length of the
input fleece zone, and is in good correspondence with the results of the experiment. A periodic change in the fleece feeding
rate led to the fact that there was a specific range of the fluctuation wavelength in the fleece feeding rate, whereas a change
in the in-process bundle thickness completely disappeared or became locally maximized in certain wavelength areas. This could
lead to a magnification or inaction of the perturbations with the corresponding wavelength in the bundle thickness; a bundle
thickness irregularity. Experiments also identified that the theoretical model accurately described the fiber accumulation
dynamics in a friction spinning process. 相似文献