芍药属组间杂交种皮开裂种子的解剖观察与胚培养

【目的】探究芍药属组间杂交种皮开裂种子的内部状态和胚培养成苗表现,为揭示种皮开裂种子的成苗潜力、提高组间远缘杂交育种效率提供参考。【方法】以24个芍药属组间杂交组合种皮开裂的种子为试验材料,解剖后观察并统计胚和胚乳的发育情况,通过离体培养观察胚的萌发和生长规律,分析不同组合种皮开裂种子发育和成苗差异。【结果】芍药属24个组间杂交组合中均出现了种皮开裂的杂交种子,平均种皮开裂率高达61.08%;1 767粒种皮开裂种子中,有11.09%的胚乳已腐烂;胚乳未腐烂种子中,约90%以上种子的胚乳存在不同程度的损伤或病变,24.18%的种子内部未观察到可见胚。对解剖得到的1 185个组间杂种胚进行离体培养发现,有24.73%的胚不萌发,63.47%的胚生长异常,仅有4.47%的胚能正常生长,得到完整植株。胚培养得到的完整植株具备良好的活力,移栽成活率达到86.79%。24个杂交组合种皮开裂种子通过离体胚培养共得到46株移栽成活的组间杂种苗,平均成苗率为2.60%,接近正常组间杂交种子的播种成苗率（2.75%）。【结论】种皮开裂现象在芍药属组间杂交种子中普遍存在,是组间远缘杂交障碍的重要表现之一,用离体胚培养技术能有效克服这类障碍,提高成苗率。     

海鲜菇菌糠微生物发酵及其在肉羊瘤胃降解特性研究

【目的】探究不同微生物菌剂对海鲜菇菌糠发酵效果的影响,并研究其在肉羊瘤胃内降解特性。【方法】以海鲜菇菌糠为主要原料,分别添加0.1%植物乳杆菌、0.1%活菌多复合发酵菌剂、0.1%活菌多复合发酵菌剂＋3%糖蜜以及3%糖蜜,以不添加菌剂和糖蜜的处理为对照组。每处理3个重复,室温厌氧发酵45 d后,取样测定其营养成分（干物质（DM）、粗蛋白（CP）、中性洗涤纤维（NDF）和酸性洗涤纤维（ADF）含量）及发酵品质（pH及乳酸、乙酸、丙酸和丁酸含量）。取发酵效果最佳处理的发酵菌糠和菌糠原料进行瘤胃降解试验,测定发酵前后海鲜菇菌糠DM、CP、NDF和ADF不同发酵时间点（4,8,12,24,48及72 h）的瘤胃降解率,并计算降解参数及有效降解率。【结果】与对照组相比,各试验组CP含量均升高,NDF含量均降低,其中0.1%活菌多复合发酵菌剂＋3%糖蜜处理发酵效果最佳,其CP含量提高了9.69%（P＜0.05）,NDF、ADF和半纤维素含量分别下降了9.12%（P＜0.05）,2.66%和28.71%。各试验组pH较对照组均显著降低（P＜0.05）,乳酸含量均升高,其中0.1%活菌多复合发酵菌剂＋3%糖蜜处理组pH值最低,为3.29,乳酸含量最高（7.84%）,较对照组提高了33.11%（P＜0.05）。0.1%活菌多复合发酵菌剂＋3%糖蜜处理组菌糠DM、CP、NDF和ADF的72 h瘤胃降解率较发酵前分别提高了8.61%,8.58%,14.75%和8.93%（P＜0.05）,有效降解率较发酵前分别提高了7.66%,11.75%,20.74%和3.39%（P＞0.05）。【结论】在海鲜菇菌糠中添加0.1%活菌多复合发酵菌剂＋3%糖蜜能明显提高其营养价值、发酵品质及其在肉羊瘤胃中的降解率。     

扭果花旗杆组织培养与再生体系的建立

【目的】以扭果花旗杆(Dontostemon elegans)根和下胚轴为外植体,建立扭果花旗杆组织培养体系,为后续遗传转化体系的建立提供技术基础。【方法】以MS培养基为基础培养基,利用萘乙酸(NAA)探究根和下胚轴直接诱导不定芽情况,利用2,4 二氯苯氧乙酸(2,4-D)、6-苄氨基嘌呤(6-BA)、NAA、苯基噻二唑基脲(TDZ)、吲哚丁酸(IBA)进行愈伤组织诱导及分化和不定芽生根试验,统计愈伤组织诱导及分化和不定芽生根情况,确定扭果花旗杆组培体系最佳培养基类型。【结果】（1）由根和下胚轴直接诱导不定芽的最适培养基分别为MS+0.3 mg/L NAA和MS+0.6 mg/L NAA,直接诱导不定芽的最佳外植体为根。（2）扭果花旗杆根和下胚轴都能诱导愈伤组织,其中根系诱导愈伤组织速度最快且状态最佳,其次为下胚轴。根系愈伤组织诱导的最佳培养基为MS+1.0 mg/L 2,4-D+0.2 mg/L 6-BA+0.1 mg/L NAA,诱导率可达100.00%;下胚轴愈伤组织诱导的最佳培养基为MS+0.3 mg/L 2,4-D+1.5 mg/L 6-BA+1.5 mg/L NAA,诱导率可达100.00%。（3）根系和下胚轴的最佳愈伤组织分化培养基均为MS+0.5 mg/L 6-BA+0.3 mg/L NAA,分化率分别为100.00%和86.66%。（4）最佳生根培养基为MS+0.5 mg/L IBA,生根率可达50%以上。（5）将组培苗移至土壤后,在光照培养室培养15 d,其存活率可达83.33%。【结论】建立的扭果花旗杆组培体系可获得与实生苗形态一致的组培苗,为扭果花旗杆遗传转化体系的建立奠定了技术基础。     

兔健宝对感染球虫病家兔血液学值的影响

本试验探讨了兔健宝对人工感染球虫病家兔的部分血液学值的影响。结果表明：红细胞及白细胞总数、嗜中性白细胞分别于感染后５～２０天、１０～２５天及５～３０天显著低于对照组（Ｐ＜０．０５）;而淋巴细胞百分率和Ｔ细胞阳转率于感染后５～３０天、１０～３０天显著高于对照组（Ｐ＜０．０５）;嗜酸性白细胞、嗜碱性白细胞和单核细胞无明显差异。由此提示：兔健宝具有减轻家兔感染球虫后的肠道出血,调节机体非特异性免疫应答反应和提高机体特异性免疫应答的活性。     

Metabolic and microbial responses in western crossbred and Meishan growing pigs fed a high-fiber diet

Four Duroc x White composite crossbred (21.8 +/- 1.0 kg BW) and four 12-wk-old Meishan purebred (20.7 +/- 1.6 kg BW) growing barrows were used to determine the relative breed differences in metabolic and microbial responses to a high-fiber diet. The pigs were trained to consume 700 g of a diet containing 35% (as-fed basis) dehydrated alfalfa meal once daily. The pigs' daily intakes of DM, N, GE, NDF, and ADF were 610 g, 16.6 g, 2.64 Mcal, 150 g, and 88 g, respectively. On d 12 after surgical catheterization of the portal vein, ileal vein, and carotid artery, a 3-d total urine and feces collection was conducted. On d 24 after surgery, each pig was placed in an open-circuit calorimeter, and its catheters were connected to a system for simultaneous measurements of oxygen consumption by portal-drained viscera and by whole body, and the net portal absorption of VFA after a 24-h fasting and during a 5-h postprandial period. The VFA measured included acetic, propionic, isobutyric, butyric, isovaleric, and valeric acids. A second 3-d total urine and feces collection was conducted on d 30 after surgery. There were no differences (P = 0.13) between the first and second collections in apparent total-tract digestibility coefficients for nutrients and N retention of pigs. Compared with Duroc x White composite crossbred pigs, Meishan pigs had lower (P = 0.05) apparent digestibility coefficients for DM, N, NDF, hemicellulose, and N retention, but their portal-drained viscera used a greater (P = 0.05) fraction of whole-body oxygen consumption. No differences (P = 0.12) were found between Duroc x White composite crossbred and Meishan pigs in total viable bacteria and cellulolytic bacteria from fecal samples, in vitro digestibility of alfalfa NDF fractions by fecal inocula, whole-body oxygen consumption, net portal absorption of VFA, total energy of absorbed VFA, and the potential of absorbed VFA for meeting the energy needs for whole-body heat production. These results indicate that, in contrast to previous beliefs, the ability of Meishan growing pigs to utilize a high-fiber diet is not superior to that of Duroc x White composite crossbred growing pigs.     

光照分布不均的米粒数目统计

通过对光照不均匀的米粒灰度图像进行最佳阈值分割和特征提取,获得对米粒数目的自动检测方法。该方法具有较强的光照分布不均和面积大小适应性。经仿真试验,检测结果可以达到97%以上。同时,相较于同类算法,该方法算法简单,运行时间较短。     

Mutations in the juxtamembrane domain of c-KIT are associated with higher grade mast cell tumors in dogs

Mast cell tumors are among the most commonly seen tumors of the skin in dogs and are more highly aggressive than mast cell tumors of other species. Some breeds display a markedly higher incidence of mast cell tumor development than others and appear to have some genetic predisposition. Recently, mutations have been found in canine mast cell tumor tissues and cell lines within the juxtamembrane domain of the protooncogene c-KIT In previous studies utilizing a small number of cases, no association between the presence of a mutation and the breed of dog or grade of the tumor could be identified. An expanded study with a larger sample set was performed to explore this possibility. The juxtamembrane domain of c-KIT was amplified using the polymerase chain reaction from genomic DNA preparations of 88 paraffin-embedded mast cell tumors from selected breeds. Mutations, consisting of duplications and deletions, were found in 12 of the tumors. A significant association was found between the presence of a mutation and a higher grade of tumor but not between breed and grade or between breed and the presence of a mutation.     

Phylogenetic analysis of Trypanosomatina (Protozoa: Kinetoplastida) based on minicircle conserved regions

Phylogenetic relationships within the suborder Trypanosomatina were inferred from the kinetoplast DNA minicircle conserved region sequences. Trees built using distance-matrix (Neighbor-Joining) and maximum parsimony methods showed that the minicircle conserved regions (CRs) provide a sensitive and specific molecular marker suitable for phylogenetic analyses of subspecies and strains of trypanosomatid flagellates, as testified by the subdivision of the genus Leishmania into the subgenera Leishmania. Viannia and Sauroleishmania. However, since Phytomonas and monogenetic parasites of insects represent the earliest diverging groups, the CRs do not seem to be useful for inference of relationships among major lineages of the order Kinetoplastida.     

Effect of virginiamycin supplementation on the performance of young grazing cattle

Three experiments have been conducted to study the effect of virginiamycin in young grazing-bulls (Experiment 1) and heifers (Experiments 2 and 3). Rotational grazing on permanent grassland was practised and animals were supplemented with 1 kg dried sugarbeet pulp per head daily. Control groups did not receive virginiamycin via the supplement, while it was incorporated at 120, 300 and 200 mg kg⁻¹ for the treatment groups in Experiments 1 to 3 respectively.
Average daily liveweight gain was significantly increased from 0·59 to 0·72 kg in Experiment 1 and from 0·73 to 0·81 kg in Experiment 3, but was not affected in Experiment 2 (0·51 vs 0·55 kg). Virginiamycin also increased liveweight gain per ha by 12, 7 and 13%, respectively, for the three experiments. Grazed area per animal was not enlarged to the same extent as the calculated daily energy allowances, which may suggest an improved digestibility and/or rumen fermentation.