A preliminary study on the use of rapid chemical tests as aids in diagnosing nutrient deficiencies in the Irish Potato     

R. E. Nylund 《American Journal of Potato Research》1948,25(6):216-224

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The influence of sprout-inhibiting and sprout-inducing treatments on the growth and yields of potatoes     

E. A. Pujals  R. E. Nylund  F. A. Krantz 《American Journal of Potato Research》1947,24(2):47-56

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Osteoarthritis: linking nitric oxide and metalloproteinases in canine articular ligament pathology     

Rajamäki MM  Sorsa T 《Veterinary journal (London, England : 1997)》2006,172(3):400-401

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Triggering a cell shape change by exploiting preexisting actomyosin contractions     

Roh-Johnson M  Shemer G  Higgins CD  McClellan JH  Werts AD  Tulu US  Gao L  Betzig E  Kiehart DP  Goldstein B 《Science (New York, N.Y.)》2012,335(6073):1232-1235

Apical constriction changes cell shapes, driving critical morphogenetic events, including gastrulation in diverse organisms and neural tube closure in vertebrates. Apical constriction is thought to be triggered by contraction of apical actomyosin networks. We found that apical actomyosin contractions began before cell shape changes in both Caenorhabitis elegans and Drosophila. In C. elegans, actomyosin networks were initially dynamic, contracting and generating cortical tension without substantial shrinking of apical surfaces. Apical cell-cell contact zones and actomyosin only later moved increasingly in concert, with no detectable change in actomyosin dynamics or cortical tension. Thus, apical constriction appears to be triggered not by a change in cortical tension, but by dynamic linking of apical cell-cell contact zones to an already contractile apical cortex.  相似文献   

影响鸡坏死性肠炎病例复制的关键因素     

袁伟康  戚南山  廖申权  Mudassar Mohiuddin  李跃龙  吕敏娜  吴彩艳  李娟  林栩慧  蔡海明  胡俊菁  于林增  肖文婉  张健騑  曹正  孙芸芸  孙铭飞  顾有方 《中国兽医学报》2021,(1):186-191

坏死性肠炎(necrotic enteritis,NE)是家禽中最重要的肠道疫病之一,呈世界性流行,严重危害养鸡业发展。人工复制鸡坏死性肠炎病例是研究该病发病机制及筛选有效药物的重要手段,然而在实际试验过程中,通常受实验动物、感染菌株、诱导病原等多方面因素影响而难以成功复制病例。鉴于此,现综述了影响鸡坏死性肠炎病例成功复制的关键因素,包括攻毒使用的实验动物、菌株毒素、菌株培养条件、诱导病因等,同时探讨了如何通过调整这些因素来改善人工复制鸡坏死性肠炎病例的严重程度,分析了鸡坏死性肠炎病例的病变评分系统,以期为鸡坏死性肠炎的实验室研究及综合防控提供理论基础。  相似文献   

Influence of 2,4-D on uniformity and specific gravity of potatoes     

D. C. Nelson  R. E. Nylund 《American Journal of Potato Research》1963,40(11):391-395

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Tetrodotoxin sensitivity of the vertebrate cardiac Na+ current     

Vornanen M  Hassinen M  Haverinen J 《Marine drugs》2011,9(11):2409-2422

Evolutionary origin and physiological significance of the tetrodotoxin (TTX) resistance of the vertebrate cardiac Na(+) current (I(Na)) is still unresolved. To this end, TTX sensitivity of the cardiac I(Na) was examined in cardiac myocytes of a cyclostome (lamprey), three teleost fishes (crucian carp, burbot and rainbow trout), a clawed frog, a snake (viper) and a bird (quail). In lamprey, teleost fishes, frog and bird the cardiac I(Na) was highly TTX-sensitive with EC(50)-values between 1.4 and 6.6 nmol·L(-1). In the snake heart, about 80% of the I(Na) was TTX-resistant with EC(50) value of 0.65 μmol·L(-1), the rest being TTX-sensitive (EC(50) = 0.5 nmol·L(-1)). Although TTX-resistance of the cardiac I(Na) appears to be limited to mammals and reptiles, the presence of TTX-resistant isoform of Na(+) channel in the lamprey heart suggest an early evolutionary origin of the TTX-resistance, perhaps in the common ancestor of all vertebrates.  相似文献   

Microbial communities, biomass, and activities in soils as affected by freeze thaw cycles     

Hannu T. Koponen  Tuula Jaakkola  Minna M. Keinänen-Toivola  Saara Kaipainen  Jaana Tuomainen  Kristina Servomaa 《Soil biology & biochemistry》2006,38(7):1861-1871

Two Finnish agricultural soils (peat soil and loamy sand) were exposed to four freeze-thaw cycles (FTC), with a temperature change from −17.3±0.4 °C to +4.1±0.4 °C. Control cores from both soils were kept at constant temperature (+6.6±2.0 °C) without FTCs. Soil N₂O and CO₂ emissions were monitored during soil thawing, and the effects of FTCs on soil microbes were studied. N₂O emissions were extremely low in peat soil, possibly due to low soil water content. Loamy sand had high N₂O emission, with the highest emission after the second FTC. Soil freeze-thaw increased anaerobic respiration in both soil types during the first 3-4 FTCs, and this increase was higher in the peat soil. The microbial community structure and biomass analysed with lipid biomarkers (phospholipid fatty acids, 3- and 2- hydroxy fatty acids) were not affected by freezing-thawing cycles, nor was soil microbial biomass carbon (MIB-C). Molecular analysis of the microbial community structure with temperature gradient gel electrophoresis (TGGE) also showed no changes due the FTCs. These results show that freezing and thawing of boreal soils does not have a strong effect on microbial biomass or community structure.  相似文献   

Scattered CaSO4-crystallites on needle surfaces after simulated acid rain as an indicator of nutrient leaching     

Satu Huttunen  Minna Turunen  Jaana Reinikainen 《Water, air, and soil pollution》1990,54(1):169-173

Two acid rain experiments were conducted, one at Oulu using transplanted seedlings of Picea abies and Pinus sylvestris, and the other with adult pines at Kevo where test plots were designated in a natural mixed stand of Pinus sylvestris and Betula tortuosa. The acid solution was made by adding H₂SO₄ and HNO3 (vol:vol 2:1, pH adjusted to 3 and 4) to clean water.The Oulu experiment was carried out from 1986 to 1989, and Kevo from 1985 to 1989. No visible injuries related directly to the acid rain treatment could be observed after 3 yr of the experiments, but microscopic examination revealed significant changes in the structure and morphology of the needles. The conifer seedlings treated at pH 3 had significant amounts of scattered CaSO₄ crystallites and characteristic piles and bows on the needle surfaces, as detected with EDS. The number of CaSO₄ crystallites was higher on the surfaces of the spruce needles than those of the pine needles. The current needles had more crystallites than the previous year's needles.  相似文献   

Malting enzyme activities, grain protein variation and yield potentials in the displaced genetic resources of barley landraces of Finland     

Hannu Ahokas  Minna Poukkula 《Genetic Resources and Crop Evolution》1999,46(3):251-260

Thirty-two unimproved landraces of barley ( Hordeum vulgare L.) based on single plant selections in SE Finland were studied. Some of the lines still had ancient features, e.g., rachis brittleness in the tip of the spike. The lines showed 17 different and 16 unique hordein patterns and three lines showed more than one pattern, suggesting heterozygosity, and six different residual grain protein patterns. The three enzyme activities (-amylase, -amylase and -glucanase) of grains germinated aseptically for 120 h were determined. The average activity levels were high compared with a standard of five global barleys and with those determined previously in wild barley (H. vulgare ssp. spontaneum (Koch) Archers et Graebn.) grown in Finland. The ssp. spontaneum sample of 257 accessions showed significantly (P<0.001) less variation in -amylase and significantly (P<0.001) lower mean activity of all three enzymes. The high variation of these chemotypes indicates great potential variation of possible use by breeders has been lost by the disappearance and displacement of local barleys with commercial cultivars since 1950 in Finland before which barley cultivation and adaptation to the local environment had occurred over more than 3000 years. Selection for currently preferable plant characteristics in the descendants of the cross of HA52 (a landrace selection) × Adorra discriminated the hordein pattern of HA52 not being directly selected. The best landraces outyield the standard cultivars especially when there was no lodging. Top yield and small grains appeared to be associated characteristics under the environmental selection pressure, conflicting with the man-made regulations of the EU.  相似文献