豫综5号玉米群体产量性状轮回选择改良效果分析

以半姊妹和相互半姊妹轮回选择改良的豫综5号5个轮次群体为材料,通过2点产量比较试验,对豫综5号群体产量及穗部性状的改良效果进行了比较研究.结果表明,随着改良轮次的增加,豫综5号群体的单株产量逐轮提高,平均每轮提高6.36%,其中,半姊妹轮回选择改良的3轮群体平均每轮提高6.30%,相互半姊妹轮回选择的改良群体提高5.51%,群体产量的变异系数从15.4%下降到12.8%,基本符合选择预期效果,群体内仍有较丰富的变异,说明2种选择方法对群体单株产量的改良是有效的.对改良群体穗部性状的比较发现,穗长和行粒数分别提高5.27%和9.96%.说明穗长和行粒数的改良效果明显,它们的提高是群体单株产量提高的主要因素.本研究还对相互轮回选择的方法和豫综5号群体改良利用等问题进行了探讨.     

玉米光周期敏感相关性状发育动态QTL定位

玉米是短日照作物,大多数热带种质对光周期非常敏感。光周期敏感性限制了温、热地区间的种质交流。研究玉米光周期敏感性的分子机理,有利于玉米种质的扩增、改良、创新,提高玉米品种对不同光周期变化的适应性。本研究以对光周期钝感的温带自交系黄早四和对光周期敏感的热带自交系CML288为亲本配置的组合衍生的一套207个重组自交系为材料,在长日照环境条件下对不同发育时期的叶片数、株(苗)高变化进行QTL分析。结果表明,双亲间的最终可见叶片数和株高差异很大;发育初期CML288的叶片数和苗高都低于黄早四,而发育后期CML288的叶片数和株高都明显高于黄早四;测定各时期F₇重组自交系间也存在显著差异。利用包含237个SSR标记、图谱总长度1 753.6 cM、平均图距7.40 cM的遗传连锁图谱,采用复合区间作图法,分别检测到控制叶片数和株(苗)高发育的QTL 11个和20个。但是,没有一个条件QTL 能在测定的几个时期都有效应。在长日照条件下,控制叶片数与株(苗)高的非条件与条件QTL主要集中在第1、9和10染色体上,特别是在第10染色体的标记umc1873附近均检测到了影响这两个性状的QTL,且在不同的发育时期单个条件和非条件QTL所解释的表型变异分别为4.34%~25.74%和10.02%~22.57%,表明这一区域可能包含光周期敏感性关键基因。     

温带和热带玉米重组自交系群体的株高QTL分析

以光周期钝感自交系黄早4和光周期敏感自交系CML 288为亲本杂交所衍生的F10代重组自交系为材料,构建了覆盖玉米10条染色体的含有237个SSR标记的遗传连锁图谱;采用复合区间作图法对3种不同长短日照环境下的株高进行QTL定位,在4个地区3个不同的光周期环境下共检测到11个与株高有关的QTL.在第1条染色体1.10区域的1个QTL在各个日照条件下都能够稳定表达;位于第10染色体10.04区域的1个主效QTL PH 10在长日照务件下特异表达,且具有较大的贡献率、效应值和LOD值,推断在该区段上存在控制玉米光周期敏感性的QTL.     

Cyclooxygenase-2 expression is associated with histologic tumor type in canine mammary carcinoma

Cyclooxygenase-2 (COX-2) is an inducible member of the family of cyclooxygenase enzymes that has been implicated in the genesis of numerous cancers. The role of COX-2 in canine mammary neoplasia remains to be more clearly elucidated. The goal of the study reported here was to determine whether a direct association between levels of COX-2 expression and tumor histologic subtype exists in canine mammary carcinoma. Immunohistochemical analysis was performed using a polyclonal antiprostaglandin G/H synthase 2 IgG COX-2 antibody. Sections from the kidneys of young dogs, which stain positive for COX-2 in the macula densa, served as positive controls. Slides were reviewed by a single pathologist, and were evaluated for COX-2 expression according to previously established scales. Positive-staining tumors were given a COX-2 staining distribution (on the basis of the percentage of positive staining cells in five 400x fields) and intensity score according to previously established scales. The product of the COX-2 staining distribution and intensity scores was calculated to create a COX-2 staining index. COX-2 expression was detected in 28 of 50 (56%) samples evaluated. Anaplastic carcinomas had a significantly higher COX-2 staining distribution, intensity, and index, compared with those for adenocarcinomas (P < 0.0001). The overall percentage of positive tumors (56%) was consistent with that of prior studies. To the authors' knowledge, these results indicate, for the first time, a direct association between COX-2 expression and tumor histologic subtype in canine mammary carcinomas. Future research directed at measuring tumor response in canine mammary carcinoma patients treated with a selective COX-2 inhibitor is indicated.     

Association between ovarihysterectomy and feline mammary carcinoma

The etiopathogenesis of feline mammary carcinoma is not well understood. Although putative, risk factors include breed, reproductive status, and regular exposure to progestins. An association between age at ovarihysterectomy (OHE) and mammary carcinoma development has not been established. Therefore, a case-control study was performed to determine the effects of OHE age, breed, progestin exposure, and parity on feline mammary carcinoma development. Cases were female cats diagnosed with mammary carcinoma by histological examination of mammary tissue. Controls were female cats not diagnosed with mammary tumors selected from the same biopsy service population. Controls were frequency matched to cases by age and year of diagnosis. Questionnaires were sent to veterinarians for 308 cases and 400 controls. The overall questionnaire response rate was 58%. Intact cats were significantly overrepresented (odds ratio [OR] 2.7, confidence interval [CI] = 1.4-5.3, P < .001) in the mammary carcinoma population. Cats spayed prior to 6 months of age had a 91% reduction in the risk of mammary carcinoma development compared with intact cats (OR 0.9, CI = 0.03-0.24). Those spayed prior to 1 year had an 86% reduction in risk (OR 0.14, CI = 0.06-0.34). Parity did not affect feline mammary carcinoma development, and too few cats had progestin exposure to determine association with mammary carcinoma. Results indicate that cats spayed before 1 year of age are at significantly decreased risk of feline mammary carcinoma development.     

Magnetic resonance imaging of focal splenic and hepatic lesions in the dog

Focal hepatic and splenic lesions in the dog are common, and approximately half of such lesions are malignant. Both incidentally discovered lesions and lesions in patients with known malignancies represent diagnostic dilemmas. Ultrasound often fails to characterize such lesions adequately. This uncertainty may result in unnecessary splenectomies and liver biopsies for benign lesions or noncurative surgery for advanced-stage malignancies. In humans, ultrasound largely has been supplanted by computed tomography and magnetic resonance imaging (MRI) for the characterization of focal hepatic and splenic lesions. The inherently high soft tissue contrast of MRI allows the differentiation of benign from malignant hepatic and splenic lesions in the human patients. In this prospective study, 35 focal lesions of either the spleen (n = 8) or the liver (n = 27) were characterized by MRI in 23 dogs. Lesions were presumptively classified as malignant or benign on the basis of MRI findings. Imaging results then were correlated with histopathologic (29) or cytologic (6) evaluation of the lesions. The overall accuracy in differentiating malignant from benign lesions was 94% (33 of 35 lesions). The overall sensitivity and specificity were 100% (95% CI, 78-100%) and 90% (95% CI, 68-99%), respectively. MRI classified malignant hepatic lesions as hepatocellular carcinoma (HCC) in all confirmed cases and correctly predicted the histologic grade of 5 HCC lesions. These results suggest that MRI is a useful modality for abdominal imaging in veterinary patients, and MRI accurately differentiated benign from malignant focal hepatic and splenic lesions in this sample of patients.     

玉米类LFY基因的克隆及其在不同光周期条件下的表达

采用每天9 h和15 h两种光照条件对热带玉米自交系CML288和温带玉米自交系黄早四进行处理。以玉米茎尖为材料，采用RT-PCR方法，分离到1个1 265 bp的全长cDNA克隆，序列比较表明其为拟南芥LFY基因的同源基因，命名为类LFY（基因登录号为DQ343237）。类LFY与同源基因zfl2、RFL、LFY和FLO的同源性依次为93%、84%、57%和57%。它的DNA序列和推论的蛋白质序列与zfl1同源性最高，其编码的蛋白质与zfl1相比在第28、29和160位分别少1个丙氨酸、脯氨酸和苏氨酸，在188位置多1个甲硫氨酸。该基因在2个供试自交系茎尖中长日照条件下不同生长时期持续表达，短日照条件下生长早期和后期不表达，其功能有待进一步研究。     

Evaluation of factors associated with prolonged hospital stay and outcome of febrile neutropenic patients receiving chemotherapy: 70 cases (1997–2010)

Febrile neutropenia (FN) is an important sequela in veterinary patients receiving chemotherapy. The purpose of this study was to identify factors associated with prolonged hospital stay and outcome in canine patients developing FN secondary to chemotherapy administration. Medical records of 70 dogs treated for FN at the University of Pennsylvania from 1997 to 2010 were retrospectively evaluated. The mean interval between chemotherapy and hospitalization was 7 days. Two‐thirds of treated patients had lymphoma. The majority of patients (70%) received vincristine or doxorubicin prior to the development of FN. Tachycardia at admission, complicating medical issues, G‐CSF use and decreasing neutrophil count after admission were associated with prolonged hospital stay. Hypotension and G‐CSF use were significantly associated with death in‐hospital. Mortality was 8.5%. Identification of factors associated with prolonged hospital stay and mortality in patients with FN may enable the development of risk‐adapted treatment guidelines to minimize chemotherapy‐associated morbidity and mortality.     

Growth Response and Fatty Acid Composition of Juvenile Procambarus clarkii Fed Different Sources of Dietary Lipid

An experiment was conducted to evaluate the effects of feeding various sources of dietary lipidon weight gain, feed conversion, survival and fatty acid composition of juvenile red swamp crawfish, Procam-barus clarkii. Six semi-purified diets containing vitamin-free casein, defatted soybean meal, 0.5% cholinechloride, 0.5 % glycine and 0.5 % cholesterol were supplemented with 6.0 % of either anchovy oil, linseed oil,soybean oil, rapeseed oil, safflower oil or pork lard. Each diet was fed to crawfish (3.07±0.21 g averageweight) in three replicate aquaria for 60 days. Survival rate, weight gain and feed conversion were best forcrawfish fed the diet containing anchovy oil. Crawfish fed the linseed oil diet had the second highest weightgain, followed by crawfish on soybean oil, repaseed oil, safflower oil and pork lard diets, respectively. Feedconversion values were a reflection of weight gain. Results showed that both n-6 and n-3 fatty acids are dietaryessential for juvenile Procambarus clarkii, although n-3 fatty acids promoted faster growth than n-6. Howev-er, highly unsaturated fatty acids (HUFA) (20 : 5n-3 and 22 : 6n-3) had better growth-promoting effect than18 : 3n-3, due probably to the limited ability of crawfish to bioconvert fatty acids to polyenoic forms of longerchain length. The fatty acid composition of the crawfish generally reflected that of the dietary lipids, especial-ly for the diets containing unsaturated fatty acids.     

对温、热带玉米杂交后代RIL的评价及其光周期敏感性研究

分析了温带玉米自交系黄早四、热带玉米自交系CML288及其衍生的F6重组家系(RIL)在中纬度和低纬度生态环境下的生育性状,对来自于同一亲本材料的F6重组家系和F3家系做了比较分析,研究了热带、亚热带玉米光周期敏感性及其相关性状的遗传特点。结果表明:在郑州长日照和三亚短日照条件下,F6重组家系的抽雄期、散粉期、吐丝期、株高、穗位高和叶片数等光周期敏感指数均表现出数量遗传特点。F6重组家系的平均值接近双亲平均值,有一定数量的双向超亲家系;F3家系通过随机选择连续自交到F6代后,生育期稍有提前,植株和穗位降低,变异范围扩大。因此,F6重组家系群体可以用于进行QTL定位分析。长、短日照两种条件下F6重组家系光周期敏感相关性状与F3家系的相关系数极显著,F6重组家系各性状变异范围与F3家系相比均有明显扩大的趋势。说明随着世代数的增加,杂合基因型家系在群体中的比例逐步减小,显性、隐性纯合基因型的家系所占的比例越来越大。