观赏李树——龙引紫叶李的选育

为提高北方城市园林的绿化水平,丰富寒地园林植物的种质资源,1991年黑龙江省农业科学院园艺分院引入俄罗斯紫叶李,经过多年的田间和生产试验观察,选育出抗寒性强、观赏价值较高的李树新品种。该品种叶片为紫红色,花为粉色,果实鲜红色;幼树茎干紫色、光滑,树姿较直立,可作为北方生态型园林城市的景观树种。2009年3月通过黑龙江省农作物品种审定委员会审定,命名为“龙引紫叶李”。     

Dependence of heterochromatic histone H3 methylation patterns on the Arabidopsis gene DDM1

The Arabidopsis gene DDM1 is required to maintain DNA methylation levels and is responsible for transposon and transgene silencing. However, rather than encoding a DNA methyltransferase, DDM1 has similarity to the SWI/SNF family of adenosine triphosphate-dependent chromatin remodeling genes, suggesting an indirect role in DNA methylation. Here we show that DDM1 is also required to maintain histone H3 methylation patterns. In wild-type heterochromatin, transposons and silent genes are associated with histone H3 methylated at lysine 9, whereas known genes are preferentially associated with methylated lysine 4. In ddm1 heterochromatin, DNA methylation is lost, and methylation of lysine 9 is largely replaced by methylation of lysine 4. Because DNA methylation has recently been shown to depend on histone H3 lysine 9 methylation, our results suggest that transposon methylation may be guided by histone H3 methylation in plant genomes. This would account for the epigenetic inheritance of hypomethylated DNA once histone H3 methylation patterns are altered.     

引进国外蓝莓品种的组织培养及快繁技术研究

以从保加利亚引进的蓝莓品种B91和B92的未萌动枝条为试验材料,进行了顶芽、茎尖和茎段的萌发与分化、茎段的继代丛生与快繁、试管苗生根与移栽等技术的研究。结果表明：对未萌动枝条进行预处理能明显提高接种效率;WPM＋ZEA 2.0 mg.L-1是接种茎段的适宜培养基,WPM＋ZEA 1.0 mg.L-1是大量产生丛生芽的快繁培养基,1/2 WPM＋IBA 2.0 mg.L-1＋NAA 0.5 mg.L-1是生根的理想培养基;在温室中草炭、河砂和园土按1∶1∶1混合,经过硫粉调酸后是试管苗移栽的较好基质;移植到示范果园的试管苗长势旺盛。     

Ileocolic junction resection in dogs and cats: 18 cases

There is limited veterinary literature about dogs or cats with ileocolic junction resection and its long-term follow-up. To evaluate the long-term outcome in a cohort of dogs and cats that underwent resection of the ileocolic junction without extensive (≥50%) small or large bowel resection. Medical records of dogs and cats that had the ileocolic junction resected were reviewed. Follow-up information was obtained either by telephone interview or e-mail correspondence with the referring veterinary surgeons. Nine dogs and nine cats were included. The most common cause of ileocolic junction resection was intussusception in dogs (5/9) and neoplasia in cats (6/9). Two dogs with ileocolic junction lymphoma died postoperatively. Only 2 of 15 animals, for which long-term follow-up information was available, had soft stools. However, three dogs with suspected chronic enteropathy required long-term treatment with hypoallergenic diets alone or in combination with medical treatment to avoid the development of diarrhoea. Four of 6 cats with ileocolic junction neoplasia were euthanised as a consequence of progressive disease. Dogs and cats undergoing ileocolic junction resection and surviving the perioperative period may have a good long-term outcome with mild or absent clinical signs but long-term medical management may be required.