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101.
Workneh F  Yang XB 《Phytopathology》2000,90(12):1375-1382
ABSTRACT Since the early 1990s, Sclerotinia stem rot, caused by Sclerotinia sclerotiorum, has caused considerable damage to soybean production in the north-central United States. To determine the extent of its distribution and associated factors, investigations were conducted in 1995 and 1996 in Illinois, Iowa, Minnesota, Missouri, and Ohio. Investigations also were conducted in 1997 and 1998 in Iowa, Minnesota, and Missouri. In each state, soybean fields were randomly selected in collaboration with the National Agricultural Statistics Service. From each field, 20 soybean stems 20 cm long (from the base) in 1995 and 1996 and full-length stems in 1997 and 1998 were sampled in a zigzag pattern. During the 4-year period, stem samples were collected from 1,983 fields and assessed for the presence or absence of the disease. Of the five states, Sclerotinia stem rot was most prevalent in north-central Iowa and southern Minnesota. Sclerotinia stem rot was not detected in Missouri during the 4-year investigation period. The disease was most prevalent in 1996 and least prevalent in 1995. The prevalence of the disease was strongly related to cumulative departures from normal maximum and minimum temperatures in July and August. The disease was more prevalent when yearly temperatures were below normal than when they were above normal. In 1996, a year with a cooler-than-normal summer, the disease was detected farther south than in 1995. In both years, the prevalence of the disease was exponentially related to latitudinal positions of the fields (R(2) = 0.93 and 0.83 for 1995 and 1996, respectively) reflecting the effect of the north-south variations in temperature. During the 4-year period, there was no relationship between precipitation and the prevalence of the disease. The lack of relationship may suggest that there was no shortage of moisture since it is one of the primary factors for disease development. The prevalence of Sclerotinia stem rot was less in no-till than in minimum-till or conventional-till fields (P = 0.001 and 0.007, respectively) and greater in minimum-till than in conventional-till fields (P = 0.07). Fields that had Sclerotinia stem rot, however, did not differ in incidence of the disease regardless of the tillage system.  相似文献   
102.
3月3日,美国乙醇工业协会(EIA)公布了12月美国乙醇产量报告,另外,近期报道称甲基叔丁基醚(MTBE)将停止使用,在此对乙醇产业市场和玉米消费以及今年剩余时间里可能会影响该产业的因素进行略为详尽的研究。图1显示出美国乙醇产业持续强劲增长的状况。3月3日EIA公布的2005年12月报告显示:美国每天乙醇产量为28万桶,再次创下月度高点。2005年美国乙醇产量为9300万桶(39亿加仑),全年平均日产量为25.5万桶。2005年乙醇产量高于2004年的8100万桶(34亿加仑),2004年日产量为22.1万桶。12月份数据显示当月用于乙醇生产的玉米用量约为1.29亿蒲式耳,…  相似文献   
103.
An 8-year-old, entire male crossbreed dog had a 2-day history of abdominal pain and straining to urinate and defecate. A diagnosis of urolithiasis with urinary retention, and probable prostatitis was made. The dog was treated with fluids and enrofloxacin. Five days later, ultrasonography of the prostate showed two hypoechoic areas compatible with abscesses. Twelve hours later, the patient started to urinate from the rectum during micturition and urethrorectal fistula was diagnosed. The omentalization of the prostatic abscesses and castration were performed and calculi were removed. The urethrorectal fistula was treated conservatively with an indwelling urinary catheter, a low residue diet and antibiotics. The dog recovered uneventfully without recurrence of the fistula.  相似文献   
104.
Diarrhoea caused by enterotoxigenic Escherichia coli (ETEC) expressing F4 (F4ab, F4ac and F4ad) fimbriae is a significant cause of mortality and morbidity in newborn and weaned pigs. The locus controlling susceptibility towards ETEC F4ab/ac has been mapped to SSC13q41, in which TFRC (transferrin receptor) was localized and considered as a positional candidate gene for ETEC F4ab/ac receptor. In this study, we determined susceptibility/resistance to ETEC F4ab/ac in a total of 755 F2 animals from a White Duroc x Erhualian intercross using a microscopic enterocyte adhesion assay. We identified two TFRC polymorphisms (SNPs 591 A>G and 632 A>G) in a single exon after comparative sequencing analysis of 2371-bp amplicons containing the complete coding region of TFRC using RNA of eight full-sib F2 animals with susceptible and resistant phenotypes. The intron sequences flanking the two exon polymorphisms were obtained, revealing an intron polymorphism (SNP 291 C>T). We genotyped the 19 founder animals of the White Duroc x Erhualian intercross for the identified polymorphisms, showing that only the 291 C>T polymorphism is a highly informative marker. We further genotyped all 59 F1 and 755 F2 animals for the 291 C>T polymorphism, and the association of this polymorphism with susceptibility/resistance to ETEC F4ab/ac in these F2 animals was evaluated by the transmission disequilibrium test. The result showed that the 291 C>T polymorphism is not a causal mutation, however, has a significant linkage disequilibrium with the ETEC F4ab/ac, especially F4ac receptor locus.  相似文献   
105.
This study was conducted to determine the effect of addition of essential amino acids (EAA) to low-protein diets on N balance in barrows. Thirty barrows (Duroc × Yorkshire) with an initial BW of 36 kg were fed 5 corn- and soybean meal-based diets containing 13.6 to 18.2% crude protein (CP) for 10 d in a randomized complete block design. The 18.2% CP diet was formulated without addition of EAA (Lys, Met or Thr). The other diets contained 13.6 to 16.5% CP and were supplemented with EAA to provide 0.83% true digestible lysine equal to that in the 18.2% CP diet. Fecal, urinary, and total N excretion as well as N retention (g/d) decreased with decreasing dietary CP level (P < 0.01). The apparent digestibility of N was almost the same for the 18.2 and 16.5 CP diets, but the value was 2% higher (P = 0.07) than that for the 13.6% CP diet. These findings indicate that, compared with the 18.2% CP diets, supplementation with three EAA to the lowest-protein diets (13.6 CP) is inadequate for maximum intestinal protein digestion, amino acid absorption, or tissue protein deposition in growing barrows.  相似文献   
106.
107.
Through a detailed case study of a two‐species (Lolium rigidum and Avena sterilis) weed community at contrasting scales, this paper examined factors that affect weed distribution across space and time in a commercial wheat field in north‐east Spain. A. sterilis showed relatively stable spatial distribution and spatial structure of its population over time at large scale, with well‐defined patches, although weed density rose quickly. L. rigidum showed poorly defined patches that were not stable across time. Interaction between species could explain to some degree the spatial distribution at large scale: a negative relationship was detected between the spatial structures of both weed populations. At fine scale, both species showed a clear interaction effect from primary dispersal (more important in A. sterilis) and secondary dispersal from combine harvesting (more important in L. rigidum).  相似文献   
108.
109.
Genetic variability in French dog breeds assessed by pedigree data   总被引:2,自引:0,他引:2  
Pedigree data of nine French dog breeds, namely Barbet (BAR), Basset fauve de Bretagne (BAF), Beauceron (BEN), Berger des Pyrénées (BRP), Bouledogue Français (BUF), Braque Saint‐Germain (BQG), Dogue de Bordeaux (DOB), Epagneul Breton (EPB) and Montagne des Pyrénées (MOP), were analysed. The effective numbers of ancestors of dogs born from 1997 to 2001 were equal to 6.7 (BAR), 40.2 (BAF), 36.5 (BEN), 16.0 (BRP), 37.0 (BUF), 13.1 (BQG), 28.9 (DOB), 33.3 (EPB) and 34.0 (MOP). The expected contributions of the major ancestors were found to be highly unbalanced in the EPB and BRP. The average coefficient of inbreeding of dogs born from 1997 to 2001 with both parents known was equal to 12.4% (BAR), 3.9% (BAF), 5.4% (BEN), 7.2% (BRP), 3.3% (BUF), 6.0% (BQG), 4.1% (DOB), 4.5% (EPB) and 4.0% (MOP). These values were found to be significantly higher than the average coefficient of kinship between the male and the female parents of these animals, except in the BAR and BQG, revealing an usual practice of mating between related animals. The results are discussed in relation with the demographic situation and the use of each breed. The method used to class an endangered breed and the ways to preserve the genetic variability, when necessary, are evoked.  相似文献   
110.
Strategies for robust quantitative comparison between different biological samples are of high importance in experiments that address biological questions beyond the establishment of protein lists. Here, we propose the use of 15N-KNO3 as the only nitrogen source in Arabidopsis cell cultures in order to achieve a metabolically fully labeled cell population. Proteins from such metabolically labeled culture are distinguishable from unlabeled protein populations by a characteristic mass shift that depends on the amino acid composition of the tryptic peptide analyzed. In addition, the metabolically labeled cell extracts are also suitable for comparative quantitative analysis of nitrogen-containing cellular metabolic complement. Protein extracts from unlabeled and from standardized 15N-labeled cells were combined into one sample for joined analytical processing. This has the advantage of (i) reduced experimental variability and (ii) immediate relative quantitation at the level of single extracted peptide and metabolite spectra. Together ease and accuracy of relative quantitation for profiling experiments is substantially improved. The metabolic labeling strategy has been validated by mixtures of protein extracts and metabolite extracts from the same cell cultures in known ratios of labeled to unlabeled extracts (1:1, 1:4, and 4:1). We conclude that saturating metabolic 15N-labeling provides a robust and affordable integrative strategy to answer questions in quantitative proteomics and nitrogen focused metabolomics.  相似文献   
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