丹东河口艳红桃可降解纸袋套袋对果实品质的影响

通过对比试验研究了丹东河口艳红桃可降解纸袋套袋对果实品质的影响,结果表明:艳红桃采用可降解纸袋套袋,能有效防治虫害和桃锈病对果实的危害并能防治裂果病。在果实快速生长期进行套袋和在着色期脱袋增加了果实色泽,提高了其商品性能。     

Untersuchungen zur Assimilatakkumulation im Weizenblatt nach Schwarzrostinfektion

Accumulation of assimilates in stem-rust-infected wheat leaves
Using wheat plants (cv. 'Prelude'), the effects of stem-rust infection on photosynthesis and assimilate partitioning were studied with the aid of the short-lived carbon isotope ¹¹C. Photosynthesis of strongly infected leaf parts declined by about 30 % within 1 day. This rapid inhibition was caused by the formation of appressoria and the growth of infection tubes into the stomata, leading to a reduction in gas exchange. Further decline of photosynthesis to 5–10 % was accompanied by the degradation of chlorophyll. Nevertheless, during sporulation, the dry weight of the infected leaf area increased by about 50 %. With the use of ¹¹C, the reduced export of photosynthate from the infected leaf part and the capture of labelled compounds from the apical leaf section were quantified. The enhanced storage of assimilates in stem-rust-infected leaves can be attributed to the increase in invertase activity.     

Plasma vitellogenin levels in male common carp Cyprinus carpio and crucian carp Carassius cuvieri of Lake Kasumigaura

In order to investigate the possible influence of estrogenic environmental endocrine disruptors on the reproductive activity of fish in Lake Kasumigaura, plasma levels of vitellogenin (VTG), a biomarker of estrogen exposure, were measured in wild and cultured male common carp Cyprinus carpio and wild crucian carp Carassius cuvieri . Testicular histology and plasma steroid hormone levels were also examined. Fish were collected from June 1998 to August 1999. Plasma VTG levels in most fish examined were below a detection limit (40 ng/mL) throughout the sampling period, and a small amount of VTG (43.5 ng/mL–1680 ng/mL) compared to that in females was detected in some fish. Active spermatogenesis in the testis and increased levels of plasma sex steroids were observed in most of the fish examined. Thus, no marked influence of estrogenic chemicals was detected in the reproductive activity of male common carp and crucian carp in Lake Kasumigaura collected from the sampling sites in the present investigation.     

大豆新品种“吉农11号”选育报告

大豆新品种“吉农11号”是以吉农8203—2×哈83-3331为母本,以吉农8330-22为父本,经品种间有性杂交,多年选育而成。2年区域试验结果:平均产量为2 823.3 kg∥hm2,比对照“吉林30号”增产9.2％;1年生产试验结果:平均产量为2 751.0 kg/hm2,比对照“吉林30号”增产14.1％。该品种2002年2月通过吉林省农作物品种审定委员会审定,其主要特点是单产水平高,稳产性好,抗病性强,无褐斑。     

Corynebacterium pseudotuberculosis infection in goats. III. The influence of age

Serological examinations for Gorynebacterium pseudotuberculosis in-fection were carried out in 14 known positive herds and in 1 herd that had beeni recently established through purchase of animals from different herds. Serum samples were collected sequentially on up to 4 occasions from animals during their first year of life. In most herds, these animals were examined clinically for superficial swellings once or twice during the same period.The adult goats in 8 infected herds were examined both clinically and serologically. Age distribution was similar in each of these herds. All serum samples were examined for antibodies against Gorynebac-terium pseudotuberculosis in both the bacterial agglutination test (BAT) and the hemolysis inhibition test (HIT).The proportion of kids which were seropositive in both tests de-creased to zero at 4 months of age. At the age of 11–12 months, the proportion of seropositive animals was about 50 % in the BAT and 30 % in the HIT.When examined when housed for the winter at the age of about 8 months (mean age), the prevalence of animals with superficial swellings was 7 %. At the age of about 1 year (mean age), 29 % of the examined animals had such lesions. In the recently established herd, only a few of the yearlings were seropositive.Titre values in BAT and HIT increased until 6 years of age. Anti-body titre values were significantly lower in yearlings than in older goats in both tests, P < 0.005. No significant difference in the propor-tion of goats with superficial swellings was seen at the different ages.     

Bovine SLC11A1 3' UTR SSCP genotype evaluated by a macrophage in vitro killing assay employing a Brucella abortus strain

The 3' untranslated region (3' UTR) of the bovine natural resistance-associated macrophage gene (NRAMP1 or SLC11A1) was genotyped in Colombian Creole Blanco Orejinegro (BON) (Bos taurus) (n = 140) and Zebu Brahman (Bos indicus) (Z) (n = 20) cattle and their crosses (BON x Zebu Brahman [B x Z] [n = 10]; Zebu Brahman x BON [Z x B] [n = 10]), and in animals from a Holstein x BON (H x B) (n = 10) cross. Direct sequencing and single-strand conformation polymorphism analysis (SSCP) helped in detecting the polymorphic behaviour. The association between resistance to brucellosis infection and SSCP genotype was evaluated using a macrophage in vitro killing assay employing a virulent Brucella abortus strain. The 3' UTR (GT) repeated polymorphism was gentoyped and its association with resistance to brucellosis was evaluated. When all breeds were grouped, a high frequency in the homozygote GT(12) (AA genotype) (0.823) and a very low frequency in the homozygote GT(10) (BB genotype) (0.047) were detected. The BON (0.963), Z x B (0.60) and H x B (1.00) cattle showed high GT(12) allele frequencies, unlike that seen for the B x Z and Zebu cattle (0.3002 and 0.218, respectively). The GT(10) allele was only found in the Zebu cattle (0.391). A significant association (p < 0.001) was found between the B. abortus macrophage in vitro killing assay phenotypes and the bovine SLC11A1 3' UTR genotypes, which suggests that the A allele may be associated with resistance. Because only nine animals had the BB genotype, the results require some confirmation in more extensive populations.     

Gain‐of‐function mutation in PTPN11 in histiocytic sarcomas of Bernese Mountain Dogs

Histiocytic sarcoma (HS) is an aggressive malignant neoplasm of dendritic cell origin that is common in certain breeds of dogs. High prevalence of fatal, disseminated HS has been described in Bernese Mountain Dogs (BMDs). Support for genetic predisposition to develop HS has been presented in several studies, but to date, causative genetic events have not been reported. In addition, no driver mutations have been identified in tumours. Recently, E76K gain‐of‐function mutation in SHP2 encoded by the PTPN11 gene has been described in human histiocytic malignancies. In our study, we identified the PTPN11^E76K in HS of BMDs. Amplification of exon 3 of the PTPN11 gene followed by Sanger sequencing was used to detect the mutation and estimate the prevalence in HS from 30 BMDs, 13 Golden Retrievers and 10 other dog breeds. The overall prevalence of PTPN11^E76K in HS of BMDs was 36.67% compared with 8.69% in other breeds. No mutation was identified in normal tissues from 10 BMDs with HS that carried the mutation and 12 control dogs with no neoplastic disease, including 6 BMDs. Increased immunoreactivity for AKT, phosphorylated ERK1/2 and phosphorylated AKT in a small subset of BMDs with PTPN11^E76K suggests that a gain‐of‐function might be mediated by the ERK and AKT pathways. These data suggest PTPN11^E76K as an important driver mutation of HS in BMDs. This information may not only aid in unravelling the tumourigenic events associated with HS in BMDs, but also help in identifying more promising therapeutic strategies.     

一株牦牛源G6P[11]型牛轮状病毒的分离鉴定及部分基因的序列分析

本研究的目的是分离、鉴定牦牛源牛轮状病毒(bovine rotavirus, BRV)。将经RT-PCR检测BRV阳性的牦牛腹泻粪便样本接种MA-104细胞,进行病毒分离和鉴定,并对其VP4、VP6和VP7完整基因进行测序,分析其分子特征。结果显示:病毒盲传3代后出现细胞病变,至第7代后出现细胞病变的时间稳定,经蚀斑纯化后测得病毒滴度为10^8.39TCID₅₀·mL^-1。分离株经RT-PCR、间接免疫荧光和电镜观察证实为BRV,命名为HY-1株;扩增HY-1株VP4、VP6和VP7完整基因序列,分析表明HY-1株为G6P[11]I2型;系统发育树显示,HY-1株VP4、VP6和VP7节段分别与中国牛源DQ-75株和印度牛源M-1和RUBV319株遗传演化关系最近,可能为重配毒株。与国内的G6型和P[11]型BRV毒株相比,HY-1株的VP4和VP7蛋白重要氨基酸位点变化较大。成功分离得到一株牦牛源BRV,基因型为G6P[11]型,为我国首次报道。     

“黄冠梨”在武威绿洲的引种表现及省力化栽培技术

以"黄冠梨"为试材,采用实地调查、定点观测和田间试验相结合的方法,通过"黄冠梨"在武威绿洲的引种和省力化栽培试验,以期达到早果、丰产、省力化的目的。结果表明:"黄冠梨"在武威绿洲表现为树姿较开张,生长势较强,萌芽率高,早果性和丰产性好;果个较大,果面光洁,外观美,成熟时果皮黄绿色;果肉洁白,可溶性固形物和可溶性糖含量高;肉质细脆多汁,风味酸甜,有浓郁香味,极耐贮藏;品质上等,适应性较强,经济效益显著。"黄冠梨"是综合性状优良的梨品种,适合省力化栽培,在武威绿洲具有良好的发展前景,极具推广价值。     

基于政府与小农散户博弈视角的农产品质量安全规制路径选择

当前小农散户农产品生产是我国农产品质量安全问题集中高发区,成为农产品质量安全治理的重点领域。该研究针对我国农产品质量安全治理存在的问题,从政府与小农散户博弈的视角建立博弈模型,分析政府实行"严管"对农户违法行为的影响,得出"严管"的预期效果是加大农户违法成本、压缩农户违法利润空间、促使农户守法、保障食品安全的结论。但对小农散户农产品质量安全治理的路径选择上,要在适度、完善的立法,严格的执法和明确的司法基础上充分发挥法律的震慑作用的同时,提高监管能力,促进小农散户规范经营,加大宣传教育,增加对小农散户的扶持力度,共同促进我国农产品质量安全水平的提升。