Effect of silver-induced enlarged hearts during the first four weeks of life on subsequent performance of turkeys     

R P Peterson  L S Jensen  P C Harrison 《Avian diseases》1973,17(4):802-806

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Genetic, agronomic and quality comparisons of two 1AL.1RS. wheat-rye chromosomal translocations   总被引：2，自引：0，他引：2  

R. A. Graybosch    J.-H. Lee    C. J. Peterson    D. R. Porter  O. K. Chung 《Plant Breeding》1999,118(2):125-131

The 1AL.1RS wheat-rye chromosomal translocation originally found in ‘Amigo’ wheat possesses resistance genes for stem rust, powdery mildew and greenbug biotypes B and C, but also has a negative effect on wheat processing quality. Recently, a second 1AL.1RS translocation carrying Gb6, a gene conferring resistance to greenbug biotypes B, C, E, G and I, was identified in the wheat germplasm line ‘GRS1201′. Protein analytical methods, and the DNA polymerase chain reaction were used to identify markers capable of differentiating the 1RS chromosome arms derived from ‘Amigo’ and ‘GRS1201′. The secalin proteins encoded by genes on 1RS chromosome arms differed in ‘Amigo’ and ‘GRS1201′. A 70 kDa secalin was found in the ‘Amigo’1AL.1RS, but did not occur in the ‘GRS1201’1AL.1RS. Polymorphisms detected by PCR primers derived from a family of moderately repetitive rye DNA sequences also differentiated the two translocations. When ‘GRS1201’was mated with a non-1RS wheat, no recombinants between 1RS markers were observed. In crosses between 1RS and non-1RS parents, both DNA markers and secalins would be useful as selectable markers for 1RS-derived greenbug resistance. Recombination between 1RS markers did occur when 1RS from ‘Amigo’ and 1RS from ‘GRS1201’were combined, but in such intermatings, the molecular markers described herein could still be used to develop a population enriched in lines carrying Gb6. No differences in grain yield or grain and flour quality characteristics were observed when lines carrying 1RS from ‘Amigo’ were compared with lines with 1RS from ‘GRS1201′. Hence, differences in secalin composition did not result in differential quality effects. When compared with sister lines with 1AL.1AS derived from the wheat cultivar ‘Redland’, lines with ‘GRS1201’had equal grain yield, but produced flours with significantly shorter mix times, weaker doughs, and lower sodium dodecyl sulphate sedimentation volumes.  相似文献   

Germination and net in vitro growth of peach, almond and peach-almond hybrid embryos in response to mannitol inclusion in the nutrient medium     

Craig A. Ledbetter  Debra E. Palmquist  Sharon J. Peterson 《Euphytica》1998,103(2):243-250

Nine Prunus accessions were evaluated for germination and plantlet growth in an in vitro osmotic screening test using mannitol as an osmoticum. Embryos from diverse peaches, almonds and peach-almond hybrids were cultured in Woody Plant Medium, and in this same medium modified with the inclusion of 350 mM mannitol. Embryos were stratified in vitro for 60 days, induced to germinate for a two week period and then allowed to develop and grow for another 20 days prior to harvest. Fresh weights of both roots and shoots as well as percent germination were recorded at harvest. The main effects of nutrient medium, germplasm type (peach, peach-almond, almond) and specific Prunus accession were all highly significant (P = 0.01) with regard to fresh weight of roots and shoots. Embryo germination was affected significantly by the inclusion of mannitol in the nutrient medium and by the particular germplasm type (P=0.01 and P=0.05, respectively). Significant interactions of nutrient medium × Prunus accession and nutrient medium × germplasm type were also detected for both root and shoot fresh weights. Almond germplasm cultured in Woody Plant Medium with 350 mM mannitol produced significantly more roots and shoots than either peaches or peach-almond hybrids grown in the same medium. Peach-almond hybrid embryos were observed to germinate at a significantly higher frequency than peach embryos when averaged across both media. Results obtained in this study indicate a wide range of average plantlet fresh weight relative to the specific germplasm challenged in the osmotic screen. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

Reduced tillage and increasing cropping intensity in the Great Plains conserves soil C   总被引：5，自引：0，他引：5  

G. A. Peterson  A. D. Halvorson  J. L. Havlin  O. R. Jones  D. J. Lyon  D. L. Tanaka 《Soil & Tillage Research》1998,47(3-4):207-218

Concern about soil organic matter losses as a result of cultivation has been voiced consistently since the early part of the 20th century. Scientists working in the US. Great Plains recognized that organic matter losses from an already small pool could have major negative consequences on soil physical properties and N supplying capacity. The advent of reduced- and no-till systems has greatly improved our ability to capture and retain precipitation in the soil during the non-crop periods of the cropping cycle, and has made it possible to reduce fallow frequency and intensify cropping systems. The purpose of this paper is to summarize the effects of reduced tillage and cropping system intensification on C storage in soils using data from experiments in North Dakota, Nebraska, Kansas, Colorado, and Texas. Decades of farming with the wheat (Triticum aestivum L.)–fallow system, the dominant farming system in the Great Plains, have accentuated soil C losses. More intensive cropping systems, made possible by the greater water conservation associated with no-till practices, have produced more grain, produced more crop residue and allowed more of it to remain on the soil surface. Combined with less soil disturbance in reduced- and no-till systems, intensive cropping has increased C storage in the soil. We also conclude that the effects of cropping system intensification on soil C should not be investigated independent of residue C still on the surface. There are many unknowns regarding how rapidly changes in soil C will occur when tillage and cropping systems are changed, but the data summarized in this paper indicate that in the surface 2.5 cm of soil, changes can be detected within 10 years. It is imperative that we continue long-term experiments to evaluate rates of change over an extended period. It is also apparent that we should include residue C, both on the surface of the soil and within the surface 2.5 cm, in our system C budgets if we are to accurately depict residue–soil C system status. The accounting of soil C must be done on a mass basis rather than on a concentration basis.  相似文献   

Pleistocene collapse of the west antarctic ice sheet     

RP Scherer  A Aldahan  S Tulaczyk  G Possnert  H Engelhardt  B Kamb 《Science (New York, N.Y.)》1998,281(5373):82-85

Some glacial sediment samples recovered from beneath the West Antarctic ice sheet at ice stream B contain Quaternary diatoms and up to 10(8) atoms of beryllium-10 per gram. Other samples contain no Quaternary diatoms and only background levels of beryllium-10 (less than 10(6) atoms per gram). The occurrence of young diatoms and high concentrations of beryllium-10 beneath grounded ice indicates that the Ross Embayment was an open marine environment after a late Pleistocene collapse of the marine ice sheet.  相似文献   

Treatment of hyperadrenocorticism in dogs: a survey of internists and dermatologists.     

E N Behrend  R J Kemppainen  T P Clark  M D Salman  M E Peterson 《Journal of the American Veterinary Medical Association》1999,215(7):938-943

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Quality Effects of Rye (Secale cerealeL.) Chromosome Arm 1RL Transferred to Wheat (Triticum aestivumL.)     

R. A. Graybosch  C. J. Peterson  O. K. Chung 《Journal of Cereal Science》1999,29(3):211

Quality effects of rye (Secale cerealeL.) chromosome arm 1RL transferred to wheat (Triticum aestivumL.) were characterised by comparison of a group 1R(1B) substitution lines and 1BL.1RS translocation lines. The experimental materials were sister lines derived from the mating Mironovskaya10/NE7060//NE80413. 1R(1B) substitution lines were identified by the presence of ryeomega- andgamma-secalins among 70% ethanol soluble proteins, combined with the presence of high molecular weight (HMW) secalin proteins in total grain protein extracts. Genes on 1RL reduced grain weight, grain hardness, Mixograph time, Mixograph tolerance and SDS sedimentation volumes. 1RL had no effect on flour yield or grain and flour protein concentrations. The HMW secalin proteins encoded by genes on 1RL most probably caused the decline in dough strength seen in 1R(1B) lines relative to that of 1BL.1RS sister lines. Reduced grain hardness might also be related to the presence of HMW secalins, although a role for additional, unidentified genes on 1RL could not be discounted.  相似文献   

Effects of light intensity, tank colour and photoperiod on swimbladder inflation success in larval striped bass, Morone saxatilis (Walbaum)   总被引：1，自引：1，他引：0  

D J Martin-Robichaud  R H Peterson 《Aquaculture Research》1998,29(8):539-547

Striped bass, Morone saxatilis (Walbaum), larvae, although physoclistous as adults, initially need to inflate their swimbladders by passing ingested air through a pneumatic duct to the swimbladder. Failure to inflate the swimbladder results in swimbladder atrophy, dysfunctional buoyancy control, deformities, and poor larval survival and growth. The present investigation studied the effects of light intensity, tank colour and photoperiod on the initial swimbladder inflation success of striped bass. In the first experiment, newly hatched larvae were reared for 2 weeks in black or white 350-L circular tanks exposed to incandescent lighting at 163 or 10 lux. Larvae were fed Artemia from 6 days post-hatching (dph). The standard length, and oil globule and yolk areas were measured. Swimbladder condition and evidence of feeding were recorded. To study the effects of photoperiod on inflation, larvae were reared in black tanks exposed to either 8 h:16 h or 16 h:8 h light:dark photoperiods at 139 lux. Striped bass inflated their swimbladders between 6 and 9 dph at 17 ^oC. Inflation success was significantly higher in black tanks (65%) compared with white tanks (42%), but light intensity did not significantly affect swimbladder inflation. Larval growth and food consumption were better in black tanks, primarily because this treatment resulted in more larvae with inflated swimbladders, although larvae with uninflated swimbladders in black tanks were longer at 12 dph than larvae with inflated swimbladders in white tanks. Larvae that successfully inflated their swimbladders fed earlier and exhibited better growth than larvae with noninflated swimbladders. Larvae reared at higher light intensities used up yolk reserves faster. Exposing striped bass larvae to 8 h:16 h light:dark photoperiods resulted in higher inflation rates (55%) compared to larvae reared at 16 h:8 h light:dark photoperiods (30%). Therefore, black tanks and short photoperiods are preferable for early rearing of striped bass larvae to maximize swimbladder inflation success.  相似文献   

Channel Catfish,Ictalurus punctatus,Fed Diets Containing Aflatoxin from Moldy Corn Do Not Experience Increased Mortality After Challenge with Edwardsiella ictaluri     

Bruce B. Manning  David J. Wise  Hamed K. Abbas  Brian C. Peterson 《Journal of the World Aquaculture Society》2011,42(4):598-602

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Preliminary recovery of coastal sharks in the south‐east United States          下载免费PDF全文

Cassidy D Peterson  Carolyn N Belcher  Dana M Bethea  William B Driggers III  Bryan S Frazier  Robert J Latour 《Fish and Fisheries》2017,18(5):845-859

Relative abundance of many shark species in the Atlantic is assessed by compiling data from several independently conducted, but somewhat spatially limited surveys. Although these localized surveys annually sample the same populations, resulting trends in yearly indices often conflict with one another, thereby hindering interpretation of abundance patterns at broad spatial scales. We used delta‐lognormal generalized linear models (GLMs) to generate indices of abundance for seven Atlantic coastal shark species from six fishery‐independent surveys along the US east coast and Gulf of Mexico from 1975 to 2014. These indices were further analysed using dynamic factor analysis (DFA) to produce simplified, broad‐scale common trends in relative abundance over the entire sampled distribution. Effects of drivers including the North Atlantic Oscillation index, the Atlantic Multidecadal Oscillation index, annually averaged sea surface temperature and species landings were evaluated within the DFA model. The two decadal oscillations and species landings were shown to affect shark distribution along south‐east US coast. Estimated common trends of relative abundance for all large coastal shark species showed similar decreasing patterns into the early 1990s, periods of sustained low index values thereafter and recent indications of recovery. Small coastal shark species exhibited more regional variability in their estimated common trends, such that two common trends were required to adequately describe patterns in relative abundance throughout the Gulf of Mexico and Atlantic. Overall, all species’ (except the Gulf of Mexico blacknose shark) time series concluded with an increasing trend, suggestive of initial recovery from past exploitation.  相似文献