The use of a modified bulk segregant analysis to identify a molecular marker linked to a scab resistance gene in apple

Almost two-hundred random sequence decamer-primers were used to screen a pair of bulked samples and the donor parent Malus floribunda clone 821 for markers linked to the V_f gene conferring resistance to apple scab (Venturia inaequalis (Cke.) Wint.). A single primer was identified which generated a PCR fragment, OPK16/1300, from the donor parent M. floribunda clone 821 and the scab-resistant selections/cultivars bulk, but not from the scab-susceptible recurrent parent bulk. Co-segregation analysis using a segregating apple progeny and polymorphism analysis of individual scab-resistant Coop selections/cultivars confirmed that this marker was linked to the scab-resistance gene V_f with a recombination frequency of 4.3%. OPK16/1300 was then cloned and sequenced. Sequence-specific primers of 25 oligonucleotides based on the marker were synthesized, and used in turn to screen M. floribunda clone 821, scab-susceptible apple cultivars, scab-resistant apple cultivars, and scab-resistant Coop selections. A pair of sequence-specific primers of clone OPK16/1300 amplified a distinct single band of the same size as the RAPD clone. Thus, a sequence characterized amplified region (SCAR) marker was developed which can be used to identify polymorphisms of OPK16/1300 based on the presence or absence of a single band. This revised version was published online in July 2006 with corrections to the Cover Date.     

Alkenyl Glucosinolate Levels in Androgenic Populations of Brassica napus

The levels of individual and total alkenyl glucosinolates in seeds of microspore-derived spontaneous diploid plants from low by high and low by low glucosinolate parent crosses were examined to assess the utility of haploidy in canola breeding. The distributions of lines in the populations supported previous proposals that alkenyl glucosinolate levels are under multigenic control. Levels of all of the individual glucosinolates were positively correlated and were significantly reduced in canola-quality material in comparison to rapeseed-quality material. The populations of microspore-derived lines from low × high crosses were skewed to high glucosinolate levels but the population from a low × low glucosinolate cross had a greater proportion of low glucosinolate lines. The former observations can be explained in terms of the dominance of genes for high glucosinolate levels in Brassica napus. The present findings contradict previous reports that androgenic lines have higher glucosinolate content than the parents and in fact, haploidy may select for low glucosinolate lines when crosses between low glucosinolate parents are used.     

Estimation of intestinal permeability in healthy dogs using the contrast medium iohexol

Background: Iohexol is a nonradioactive marker that has been used successfully to test intestinal permeability in humans with inflammatory bowel disease. There is evidence in dogs that iohexol shares a similar permeability pathway as ⁵¹chromium‐EDTA, the gold standard marker. Objective: The objective of this study was to determine an optimal oral iohexol dosage for an intestinal permeability serum test (IPST) and to use the test to estimate intestinal permeability in healthy dogs. Methods: Eight clinically healthy dogs free of gastrointestinal, liver, and pancreatic disease were used in the study. Dosages of 0.25, 0.5, 1.0, 2.0, and 4.0 mL/kg of Omnipaque‐350 (iohexol) were administered to 2 dogs at weekly intervals. Iohexol concentration was determined in serum samples obtained hourly for 6 hours after administration by high‐performance liquid chromatography. Using the optimal dosage, iohexol was administered to 8 dogs twice, 6–36 days (mean 10 days) apart, and coefficients of variation (CVs) for iohexol concentration were calculated. Results: A dosage of 2.0 mL/kg was chosen as optimal for the IPST, based on ease of iohexol detection in serum, intestinal contrast, and clinical effects of iohexol. Following administration of this dose to healthy dogs, mean (±SD) serum iohexol concentrations were 8.74±4.38, 11.89±5.67, 12.40±5.47, 9.23±5.54, 7.61±5.13, and 5.27±2.67 μg/mL at 1, 2, 3, 4, 5, and 6 hours after iohexol administration, respectively. CVs between the 2 test days were 28–45%. Conclusions: Using the iohexol dosage established in this study, the iohexol IPST was easy to perform as a marker for intestinal permeability in dogs. Further studies to establish reference intervals and evaluate the diagnostic value of the iohexol IPST in dogs with gastrointestinal disease are warranted.     

徐州矿区充填复垦土壤特性实验研究

为了研究矿区复垦土壤的特性、环境质量状况,探寻矿区特殊生态环境中污染物料的时间路径、人工土壤的质量品质,为煤矿塌陷区的充填复垦、环境治理提供依据,采用对复垦场地进行实验研究和数据分析的方法,对不同物料充填复垦场地的土壤特性进行比较分析.结果发现:(1)土壤环境:从渗透性来说,矸石复垦场地的保水性高于粉煤灰复垦场地,土层的保水性高于充填物料层的保水性;从土壤紧实度来说,粉煤灰充填复垦场地充填物料层的紧实度低于土层的紧实度,但都在适宜作物生长的范围内;对照地的土壤紧实度偏高;粉煤灰充填场地的土壤偏碱性;(2)土壤品质:粉煤灰充填土壤能够正常种植小麦、稻、草本的植物、蔬菜等;粉煤灰充填场地的土层虽然是沙土,但比较容易板结,不利于水分的渗透,而底层的粉煤灰保水性比较差;煤矸石充填复垦场地表层覆土厚度不均匀,且煤矸石保水保肥性比较差;(3)充填土壤的适种性和产量分析:粉煤灰回填的土壤适合草本蔬菜类植物的种植,单产与正常产量相当;对于种植稻的田块,保持正常的单产水平;种植小麦的产量受到影响.     

徐州矿区充填复垦土壤特性实验研究

为了研究矿区复垦土壤的特性、环境质量状况,探寻矿区特殊生态环境中的污染物料的时间路径、人工土壤的质量品质,为煤矿塌陷区的充填复垦、环境治理提供依据,采用对复垦场地进行实验研究和数据分析的方法,对不同物料充填复垦场地的土壤特性进行比较分析。结果发现：①土壤环境：从渗透性来说,矸石复垦场地的保水性高于粉煤灰复垦场地,土层的保水性高于充填物料层的保水性;从土壤紧实度来说,粉煤灰充填复垦场地充填物料层的紧实度低于土层的紧实度,但都在适宜作物生长的范围内;比照地的土壤紧实度偏高;粉煤灰充填场地的土壤偏碱性;②土壤品质：粉煤灰充填土壤能够正常种植小麦、稻、草本的植物、蔬菜等;粉煤灰充填场地的土层虽然是沙土,但比较容易板结,不利于水分的渗透,而底层的粉煤灰保水性比较差;煤矸石充填复垦场地表层覆土厚度不均匀,且煤矸石保水保肥性比较差;③充填土壤的适种性和产量分析：粉煤灰回填的土壤适合草本蔬菜类植物的种植,单产与正常产量相当;对于种植稻的田块,保持正常的单产水平;种植小麦的产量受到影响。