微量Bradford法测定提纯禽结核菌素蛋白含量   总被引：4，自引：0，他引：4  

程君生  毛开荣  丁家波  蒋玉文 《中国兽药杂志》2007,41(6):9-11

研究用96孔微量板Bradford法测定提纯禽结核菌素蛋白含量。通过不同浓度的待测禽结核菌素与考马斯亮蓝G-250溶液混合后，在595nm光波下测定各孔样品的OD值。微量Bradford法检测禽结核菌素的线性范围是50—1000μg／mL，相关系数为0．999，最低定量限为50μg／mL。试验用3支禽结核菌素国际参照品，分别配制成125、250、500μg／mL三种不同浓度，每支每种浓度测定4次，计算实际测得的蛋白质浓度。结果显示，批内相对标准偏差为1．6％～4．4％；批间相对标准偏差0．7％-2．2％。研究结果表明微量Bradford法可作为测定禽结核菌素蛋白含量的一种方法。  相似文献   

An acute outbreak of teat lesions affecting 38% of a dairy herd in Northland     

KR Petrovski 《New Zealand veterinary journal》2013,61(2):162-163

Extract

Teat lesions are common in dairy cattle in New Zealand. Most of the infectious cases are caused by pseudocowpox virus, but lesions similar to those caused by bovine herpesvirus (BHV)-2 have been described clinically and confirmed serologically in New Zealand (Horner and Raynel 1988). BHV-2 and BHV-4 cause an acute viral disease in cattle known as bovine herpes mammillitis or ulcerative mammillitis (Hillerton et al 2001). Presumptive cases have been reported in New Zealand based on the nature and distribution of lesions (Daniel 1970). The disease is probably endemic in New Zealand but is poorly documented and generally considered to be mild and sporadic. The main differential diagnosis is pseudocowpox, which is often also present in herds affected with bovine herpes mammillitis, and dual infections of individual cattle have been reported (Gibbs et al 1972). To my knowledge, neither BHV-2 nor BHV-4 have yet been isolated in New Zealand.  相似文献   

Quantifying Transport Between the Tropical and Mid-Latitude Lower Stratosphere     

CM Volk  JW Elkins  DW Fahey  RJ Salawitch  GS Dutton  JM Gilligan  MH Proffitt  M Loewenstein  JR Podolske  K Minschwaner  JJ Margitan  KR Chan 《Science (New York, N.Y.)》1996,272(5269):1763-1768

Airborne in situ observations of molecules with a wide range of lifetimes (methane, nitrous oxide, reactive nitrogen, ozone, chlorinated halocarbons, and halon-1211), used in a tropical tracer model, show that mid-latitude air is entrained into the tropical lower stratosphere within about 13.5 months; transport is faster in the reverse direction. Because exchange with the tropics is slower than global photochemical models generally assume, ozone at mid-latitudes appears to be more sensitive to elevated levels of industrial chlorine than is currently predicted. Nevertheless, about 45 percent of air in the tropical ascent region at 21 kilometers is of mid-latitude origin, implying that emissions from supersonic aircraft could reach the middle stratosphere.  相似文献   

Polarization-modulated smectic liquid crystal phases     

Coleman DA  Fernsler J  Chattham N  Nakata M  Takanishi Y  Körblova E  Link DR  Shao RF  Jang WG  Maclennan JE  Mondainn-Monval O  Boyer C  Weissflog W  Pelzl G  Chien LC  Zasadzinski J  Watanabe J  Walba DM  Takezoe H  Clark NA 《Science (New York, N.Y.)》2003,301(5637):1204-1211

Any polar-ordered material with a spatially uniform polarization field is internally frustrated: The symmetry-required local preference for polarization is to be nonuniform, i.e., to be locally bouquet-like or "splayed." However, it is impossible to achieve splay of a preferred sign everywhere in space unless appropriate defects are introduced into the field. Typically, in materials like ferroelectric crystals or liquid crystals, such defects are not thermally stable, so that the local preference is globally frustrated and the polarization field remains uniform. Here, we report a class of fluid polar smectic liquid crystals in which local splay prevails in the form of periodic supermolecular-scale polarization modulation stripes coupled to layer undulation waves. The polar domains are locally chiral, and organized into patterns of alternating handedness and polarity. The fluid-layer undulations enable an extraordinary menagerie of filament and planar structures that identify such phases.  相似文献   

Moon Illusion: An Event in Imaginary Space     

Gruber HE  King WL  Link S 《Science (New York, N.Y.)》1963,139(3556):750-752

The illusion was obtained with artificial moons viewed against a luminous ceiling, and also with an imaginary ceiling induced by first showing a luminous ceiling and then removing it before the moons were introduced.  相似文献   

Heterosis and inheritance of drought tolerance in faba bean, Vicia faba L.     

A. A. Abdelmula  W. Link  E. Von  Kittlitz D. Stelling 《Plant Breeding》1999,118(6):485-490

Twelve parental lines of faba beans and 27 F₁ hybrids derived from them were field-tested under a dry and a well-watered treatment, at two German locations (Göttingen, Hohenheim) in two years (1995, 1996). Drought was artificially induced using rain shelters from anthesis until maturity. Data were collected on yield under dry (Yd) and well-watered (Yw) conditions. Drought tolerance was assessed as Yd/Yw. The mid-parent heterosis was significant for Yd and Yw, but not for Yd/Yw. Relative heterosis for Yd (52.0%) was greater than for Yw (39.3%). Parental heritability was greater for Yw (0.86) than for Yd (0.61). However, it was similar for both traits in F₁ hybrids (0.65 and 0.66). Principal component analysis showed that F₁ hybrids exhibited the same pattern of adaptation as their parents. The heritability of drought tolerance was 0.48 in F₁ hybrids and 0.70 in parents. Attention should be paid to its negative correlation with yield. Several hybrids combined high tolerance, a favourable pattern of adaptation and appropriate performance.  相似文献   

Comparison of intra- and inter-pool crosses in faba beans (Vicia faba L.). I. Hybrid performance and heterosis in Mediterranean and German environments     

W. Link    B. Schill    A. C. Barbera    J. I. Cubero    A. Filippetti    L. Stringi    E. von  Kittlitz  A. E. Melchinger 《Plant Breeding》1996,115(5):352-360

Two recently detected, promising CMS systems in faba bean have opened up new possibilities in hybrid breeding. This study was conducted to determine hybrid performance and heterosis of 33 intra-pool and 66 inter-pool crosses from a factorial of six European small-seeded (Minor), six European large-seeded (Major), and eight Mediterranean faba bean lines. The parent lines and F₁ crosses were evaluated at two German and seven Mediterranean environments for anthesis, maturity, yield, yield components and plant height. Yield in the Mediterranean environments was 60% of that in the German environments. European Minor lines and their intra-pool crosses were unadapted to Mediterranean environments and yielded only 31 % compared with the Mediterranean lines and their crosses, whereas European Major genotypes yielded 58%. In German environments the European crosses yielded 107% of the Mediterranean crosses. Heterotic yield increase over the parental mean was largest for European Minor x Mediterranean inter-pool crosses, amounting to 95% in the Mediterranean and 73% in German environments. Our results confirmed the expectation of an increased heterosis in inter-pool over intra-pool hybrids and poor adaptation of European genotypes in Mediterranean environments. In the latter, Mediterranean intra-pool hybrids were the most promising, whereas in Germany inter-pool hybrids of the European Minor × Mediterranean type were most promising.  相似文献   

Riboswitches in eubacteria sense the second messenger cyclic di-GMP     

Sudarsan N  Lee ER  Weinberg Z  Moy RH  Kim JN  Link KH  Breaker RR 《Science (New York, N.Y.)》2008,321(5887):411-413

Cyclic di-guanosine monophosphate (di-GMP) is a circular RNA dinucleotide that functions as a second messenger in diverse species of bacteria to trigger wide-ranging physiological changes, including cell differentiation, conversion between motile and biofilm lifestyles, and virulence gene expression. However, the mechanisms by which cyclic di-GMP regulates gene expression have remained a mystery. We found that cyclic di-GMP in many bacterial species is sensed by a riboswitch class in messenger RNA that controls the expression of genes involved in numerous fundamental cellular processes. A variety of cyclic di-GMP regulons are revealed, including some riboswitches associated with virulence gene expression, pilus formation, and flagellum biosynthesis. In addition, sequences matching the consensus for cyclic di-GMP riboswitches are present in the genome of a bacteriophage.  相似文献   

Determining tree water acquisition zones with stable isotopes in a temperate tree-based intercropping system     

Candice M. Link  Naresh V. Thevathasan  Andrew M. Gordon  Marney E. Isaac 《Agroforestry Systems》2015,89(4):611-620

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Yield Stability in Faba Bean,Vicia faba L. 1. Variation Among Inbred Lines*     

W. Link  D. Stelling  E. Ebmeyer 《Plant Breeding》1994,112(1):24-29

Cultivation of faba beans (Vicia faba L.) is hampered by poor yield stability. The genetic variation at the homozygous level for yield stability in the gene pool of the small-seeded and indeterminate European faba beans and the usefulness of auxiliary traits for the improvement of yield stability were investigated. The concept of stability, based on the regression technique, was applied. A sample of 36 faba bean lines was tested in 16 environments and a subsample of eight lines was tested in 11 additional environments. Significant differences were found between lines for yield stability parameters, but the repeatability of the results was limited. Early maturity correlated markedly (r = 0.51^**) with one of the yield stability parameters (deviation from regression). Although lodging resistance was not correlated with the stability parameters, it proved to be a safety factor for performance.  相似文献