GeneScan analysis to detect clonality of T-cell receptor γ gene rearrangement in feline lymphoid neoplasms

Lymphoid neoplasms are usually diagnosed on the basis of cytological and histopathological findings. However, in some cases, discrimination of lymphoid neoplasms from reactive lymphoid proliferation is difficult. Polymerase chain reaction (PCR) amplification of the complementarity-determining region (CDR) 3 of the T-cell receptor (TCR) γ gene can be used to assess clonality of T-cell populations as a supportive diagnostic tool for T-cell neoplasms. Because the length variation in the TCRγ CDR3 is relatively small, false positive results may occur in non-neoplastic T-cell populations in the absence of high-resolution analytical methods for PCR products. In the present study, a PCR assay system was developed to detect clonal TCRγ gene rearrangement in feline lymphoid cells using GeneScan analysis. Thirty T-cell neoplasms, 27 B-cell neoplasms, and 34 non-neoplastic tissues were subjected to the newly developed TCRγ gene rearrangement analysis. Clonal TCRγ gene rearrangement was detected in 26 of 30 (87%) T-cell neoplasms, 2 of 27 (7%) B-cell neoplasms, and 1 of 34 (3%) non-neoplastic tissues. To compare GeneScan analysis with conventional PAGE and heteroduplex analysis, 20 clonal and 20 polyclonal samples were subjected to both analyses. Most of the results were concordant between the 2 analyses; however, several clonal peaks (bands) appeared as a single band when analyzed via conventional PAGE with heteroduplex analysis in 4 of the 20 (20%) clonal samples as a result of the difference in resolution. The PCR assay system to detect clonal TCRγ gene rearrangement in feline lymphoid cells, using GeneScan analysis, would be a useful molecular diagnostic tool for feline T-cell neoplasms, with high fidelity.     

An apparatus for collecting total conidia of Blumeria graminis f.sp. hordei from leaf colonies using electrostatic attraction

Conidia from living conidiophores of barley powdery mildew ( Blumeria graminis f.sp. hordei ) on host leaves were collected consecutively using an electrostatic spore collector. The collector consisted of an electrical conductor plate linked to an electrostatic voltage generator and insulator plates placed abreast on a timed conveyer. The conductor plate was negatively charged by the potential supplied from the voltage generator. The negatively charged conductor plate caused dielectric polarization of the insulator plate, and the surface charge on the insulator plate attracted mature conidia abstricted from conidiophores on colonies growing on leaves placed 2 cm from the insulator plate. The surface charge on the insulator plate was proportional to the voltage applied to the conductor plate. Under optimized conditions, abstricted conidia were attracted to the electrostatically activated insulator plates without any detriment to their survival. During a colony's life span of c . 460 h, conidia were released throughout the day and c . 12 × 10⁴ conidia were collected during the lifetime of the colony. This is the first report on the direct quantification of progeny conidia produced by powdery mildew infecting host leaves.     

Effect of dexamethasone on the expression of atrogin‐1/MAFbx in chick skeletal muscle

Expression of atrogin‐1/MAFbx, a muscle‐specific E3 ubiquitin ligase, is high under catabolic conditions, that result in muscle atrophy. Messenger RNA (mRNA) expression of atrogin‐1/MAFbx is increased by the glucocorticoid dexamethasone in mammalian skeletal muscle. This study investigated the effects of dexamethasone on expression of atrogin‐1/MAFbx in skeletal muscle of neonatal chicks and in chick myotubes. Chicks were given a single intraperitoneal injection of dexamethasone at a concentration of 10 mg/kg body weight. Twenty‐four hours after dexamethasone administration, the Pectoralis muscle weight of chicks was decreased. mRNA expression of atrogin‐1/MAFbx in skeletal muscle of chicks was significantly increased by dexamethasone administration. Expression of other proteolytic‐related genes (20S proteasome C2 subunit, m‐calpain large subunit, and cathepsin B) in skeletal muscle of chicks was not increased by dexamethasone administration. Chick myotubes were incubated with dexamethasone (1, 10 or 100 µmol/L) for 6 h. Expression of atrogin‐1/MAFbx mRNA in chick myotubes was increased in the presence of all concentrations of dexamethasone. However, expression of other proteolytic‐related genes (20S proteasome C2 subunit, m‐calpain large subunit and cathepsin B) in chick myotubes was not affected by dexamethasone treatment. These results indicate that dexamethasone enhances atrogin‐1/MAFbx expression in chick skeletal muscle, resulting in increased muscle atrophy.     

化学和生物学处理对玉米秸秆营养价值的影响

分别使用尿素、氨和纷纷素酶等处理于玉米秸，测定了处理前后化学成分变化，并用尼龙袋法测定了秸秆干物质的瘤胃分解特性。表明：与未处理比较，尿素处理组组蛋白质含量显著提高，尿素添加量对其无影响，但贮存15d粗蛋白含量较低；氨处理组（添加3．0％氨）的粗蛋白质含量最高，处理时间无显著差异。酰性洗涤木质素含量氨处理组添加1．5％和3．0％比未处理有下降的趋势（P＜0．05）。干物质的瘤胃内的最大分解率（a b)随添加量提高有增大趋势，但尿素处理组贮存15d有下降趋势；氨处理组贮存期间不见显著值差别，但3．0％氨添加量有升高趋势。纤维素酶在添加和贮藏期间都无显著变化。作为玉米秸秆的营养价值的改善方法，尿素处理（2．65％）30d常温贮存，氨处理（3．0％）15d贮存较为合适。     

不同粗精比日粮对绵羊小肠中瘤胃微生物蛋白质利用的影响

用4 只装有瘤胃瘘管、十二指肠瘘管和回肠瘘管的去势(公母各半)萨福克羊(体重平均为45.5±5.2 kg),在不同粗精比日粮条件下,研究瘤胃细菌、纤毛虫体蛋白质在小肠内的利用情况。结果表明:到达十二指肠的瘤胃细菌和纤毛虫的量,随日粮中精饲料水平的提高而显著减少(P< 0.05)。与此相反,过瘤胃饲料蛋白质的量则显著增加(P< 0.05)。小肠内的细菌利用率显著受日粮变化的影响,而纤毛虫利用率则不易受日粮影响,且显著地高于细菌的利用率(P<0.05)。小肠内被吸收的细菌和纤毛虫对微生物氮的贡献率在全试验组中分别平均约为50% 。     

A review of ghost fishing: scientific approaches to evaluation and solutions

ABSTRACT:   Research on ghost fishing became active in the late 1980s. Ghost fishing has been confirmed for traps, gillnets, trammel-nets and small seine nets. Some lost traps are functional for a long period of time, even in shallow waters. Consequences for gillnets after loss depend on seabed conditions. The ghost fishing function of gillnets remaining on flat seabeds declines rapidly with decreasing heights and increasing visibility. Gillnets left tangled around an artificial reef, for example, three-dimensionally maintain the initial magnitude of ghost fishing for a long period of time, even after badly fouled. There are increasing numbers of researches working on the total number of mortality per gear after gear loss for gillnets and trammel-nets. It has become also possible to estimate the total number of mortality for a unit period of time in a certain fishing sector. This paper reviews research which has provided evidence and quantitative data on ghost fishing, and proposes five items important for future studies on ghost fishing.