伪狂犬病病毒吉林分离株感染BHK-21细胞的超微结构变化

以猪伪狂犬病病毒(PRV)吉林分离株PRV-JL感染体外培养的BHK-21细胞为模型,通过透射电镜对PRV的形态发生学和宿主细胞超微结构的动态变化规律进行研究。结果显示,PRV能导致BHK-21细胞圆缩,并发生细胞融合,形成合胞体;电镜观察到的病毒粒子呈球形或椭圆形,成熟的病毒粒子直径大小为140~210 nm,未成熟病毒粒子直径为90~150 nm,多呈中空状,部分呈致密核芯。病毒吸附于细胞后以膜融合的方式进入细胞,在胞核内复制,装配好的病毒粒子以出芽的方式离开细胞核,获得最初的囊膜,进入胞浆;在胞浆内的病毒粒子又利用高尔基体的膜结构合成第2层囊膜,形成完整的病毒粒子;最后包裹有完整病毒粒子的高尔基囊泡与细胞膜发生融合,将病毒粒子释放到细胞外。感染细胞超微结构变化主要表现为:细胞胞浆空泡增多,内质网扩张,线粒体增生、嵴肿胀、脱落,最后空泡化,整个细胞裂解、破碎。     

Apigenin di-C-glycosides (ACG) content and composition in grains of bread wheat (Triticum aestivum) and related species

Apigenin di-C-glycosides (ACGs) are present in the grain of bread wheat and other related cereals primarily as one or two sets of Wesseley-Moser isomers containing either arabinose and glucose (ACG1) or arabinose and galactose (ACG2) on the A ring of apigenin. These compounds may contribute to the yellow colour of wheat-based products made under alkaline conditions and in addition, have possible roles in a number of plant physiology processes and human health. The aims of this investigation were to survey genetic variation for ACG content and composition in hexaploid bread wheat (Triticum aestivum L.) and to examine ACGs in the putative progenitors of hexaploid wheat and available genetic stocks as a first step towards understanding the mechanisms involved in their biosynthesis and genetic control. Substantial variation in both grain ACG content and the ratio, ACG1/ACG2, were identified within bread wheat cultivars and related species. Genotype controlled the major portion of the variation. ACG content appeared to be a multigenic trait whereas variation in ACG1/ACG2 was associated with a limited number of chromosomes, in particular chromosomes 1B, 7B and 7D. The results suggest that it should be possible to manipulate both ACG content and composition traits through breeding.     

Jasmonic acid alleviates negative impacts of cadmium stress by modifying osmolytes and antioxidants in faba bean (Vicia faba L.)

We examined the role of jasmonic acid (JA) in faba bean under cadmium (Cd) stress, which reduces the growth, biomass yield, leaf relative water content (LRWC) and pigment systems. Hydrogen peroxide (H₂O₂) and lipid peroxidation (malondialdehyde [MDA]) levels increased by 2.78 and 2.24-fold, respectively, in plants under Cd stress, resulting in enhanced electrolyte leakage. Following foliar application to Cd-treated plants, JA restored growth, biomass yield, LRWC and pigment systems to appreciable levels and reduced levels of H₂O₂, MDA and electrolyte leakage. Proline and glycine betaine concentrations increased by 5.73 and 2.61-fold, respectively, in faba bean under Cd stress, with even higher concentrations observed following JA application to Cd-stressed plants. Superoxide dismutase, catalase, ascorbate peroxidase and glutathione reductase levels rose by 87.47%, 130.54%, 132.55% and 37.79%, respectively, with Cd toxicity, with further enhancement of antioxidant activities observed following foliar application of JA. Accumulation of Cd in roots, shoots and leaves was also minimized by external supplementation of JA. In conclusion, JA mitigates the negative impacts of Cd stress in faba bean plants by inhibiting the accumulation of Cd, H₂O₂ and MDA, and by enhancing osmolyte and antioxidant activities that reduce oxidative stress.     

Clindamycin in the treatment of Babesia gibsoni infections in dogs

This report examines the effectiveness of clindamycin for the treatment of babesiosis in dogs (n=10) experimentally infected with Babesia gibsoni (B. gibsoni). Clindamycin (25 mg/kg body weight, per os, q 12 hours for 14 days) gradually reduced parasitemia levels and induced morphological changes that indicated degeneration of parasites (e.g., segmentation; size reduction; localization in the cell limbic and/or torn state of the nucleus; and swelling, decrease, or disappearance of the cytoplasm) in the majority of dogs. Clindamycin treatment reduced the clinical symptoms characteristic of Babesia infection, including anemia, anorexia, and listlessness. Clindamycin might be useful as a medicine for treatment of B. gibsoni infection.     

Influences of Follicular Size on Parthenogenetic Activation and in Vitro Heat Shock on the Cytoskeleton in Cattle Oocytes

The availability of cow ovaries from the slaughterhouse has been very limited in Taiwan. To maximize the use of cow ovaries for research purposes, whole ovary dissection was performed and the developmental competence of the oocytes derived from different sizes of follicles was assessed by the rates of in vitro maturation (IVM) and parthenogenetic activation of the oocytes in Experiment 1 (Exp 1). Cumulus-oocyte complexes (COCs) derived from small (1-2 mm) and large (3-8 mm) follicles were subjected to standard IVM culture for 24 h. Mature oocytes were selected and then parthenogenetically activated using A23187 (5 microm, 5 min) or thimerosal (200 microm, 10 min) alone or combined with 6-dimethylaminopurine (2.5 mm and 3.5 h, respectively). Activation rates of the oocytes, neither from the large nor small follicles, were affected by different activation treatments (single or combined stimuli). Whereas maturation rates for the oocytes from large follicles were superior to those from small follicles in both the single (59% vs 45%) and combined treatments (76% vs 40%; p < 0.05). To understand how prolonged heat shock (HS) influences cytoskeletal configurations of mature bovine oocytes, in Experiment 2 (Exp 2), matured oocytes derived from large follicles were randomly allocated to different durations of HS treatments at 41.5 degrees C for 0 (C0h, control, n = 12), 1 (HS1h, n = 28), 2 (HS2h, n = 31), and 4 h (HS4h, n = 30). An additional control group was cultured for 4 h without HS (38.5 degrees C, 4 h, n = 35). Alterations in nuclear structures, microtubules (MTs), and microfilaments (MFs) of the oocytes were examined. Abnormalities in the chromosomes, spindle MTs and the percentages of oocytes with cytoplasmic MTs increased with time of HS treatment. The intensity of the MF distribution in the HS oocytes was also altered. Significant changes in the cytoskeleton after HS may be associated with the reduced development under hyperthermia and, perhaps, with the low pregnancy rates of the animals during hot seasons.     

Elevation change of the southern greenland ice sheet

Seasat and Geosat satellite altimeter measurements for the Greenland ice sheet (south of 72 degreesN latitude) show that surface elevations above 2000 meters increased at an average rate of only 1. 5 +/- 0.5 centimeters per year from 1978 to 1988. In contrast, elevation changes varied regionally from -15 to +18 centimeters per year, seasonally by +/-15 centimeters, and interannually by +/-8 centimeters. The average growth rate is too small to determine if the Greenland ice sheet is undergoing a long-term change due to a warmer polar climate.     

Cucumber mosaic cucumovirus incidence in open‐field tomato in the Olympia area and trap captures of alate aphids*

Cucumber mosaic cucumovirus (CMV) has been the most serious pathogen of tomato in Greece for the last 15 years, causing tomato shrinkage, tomato necrosis and tomato fruit necrosis. In an epidemiological study in Eleia county, one of the main centres of production of processing tomato in Greece and one most affected by CMV, it was confirmed that the virus had an extremely high frequency. Disease frequency and severity was found to have a patchy spatial and temporal distribution at county, zone and locality level, during the years and within 1998, the main year of experimentation (and a disastrous year for CMV). Great variation was found in the trends of infection frequencies during the growing season of 1998 in the 15 experimental fields but all were finally 100% or almost 100% infected. The trends of infection frequency in these 15 fields paralleled total captures of alate aphids by a Rothamsted‐type trap, whereas in one of these fields, with a Moericke‐type trap, these parallel captures were composed almost exclusively of Aphis spiraecola.