棉花纤维突变体胚珠发育过程中主要生化物质的积累特征

采用4种不同类型的棉花纤维突变体和一个正常对照TM-1,分析比较了胚珠发育过程中,纤维和种皮内纤维素,种仁内脂肪、可溶性糖和蛋白质等成份的积累特征及诸成份与纤维素含量的相关关系.结果表明,棉花纤维突变体的胚珠不仅生化物质动态变化有着较大的差异,而且其生化物质的组成差异也很大.纤维突变体的纤维素含量低,种仁蛋白质含量低,脂肪含量高.纤维素含量与种仁内脂肪含量呈显著或极显著正相关;与纤维可溶性糖,纤维蛋白质有显著的相关性,呈显著负相关.     

First report of porcine circovirus type 2 infections in Cuba

To obtain information about the porcine circovirus type 2 (PCV2) infection status of pigs in Cuba and the probable association of PCV2 with other porcine viruses, tissue samples collected from ill pigs were evaluated using polymerase chain reaction (PCR). The PCR analysis showed that 67.7% of the samples (23/34) from seven swine herds of six different geographic regions were detected to be positive for PCV2. Ten of the 23 PCV2 positive samples (43.5%) shown a concurrent infection with porcine parvovirus (PPV) and 17 of 23 PCV2 positive samples (73.9%) exhibited a concomitant infection with classical swine fever virus (CSFV). This study is the first report of PCV2 infecting pigs with different clinical conditions in Cuban swine herds and provides evidence of PCV2 co-infection with PPV and CSFV in the field.     

Comparison of slot blot nucleic acid hybridization, immunofluorescence, and virus isolation techniques to detect bluetongue virus in blood mononuclear cells from cattle with experimentally induced infection.

A slot blot hybridization technique was applied for detection of bluetongue virus (BTV) in blood mononuclear cells (BMNC) obtained from cattle with experimentally induced infection. This technique lacked sensitivity to detect the viral nucleic acid directly in clinical specimens. When aliquots of mononuclear cells from these cattle were cultivated in vitro for 10 days to amplify virus titer, only 33.3% of the samples collected during viremia gave a positive signal in the slot blot hybridization format. By contrast, results for 34.3% of noncultured and 63.3% of cultured mononuclear cell samples collected during viremia were positive by immunofluorescence. The average number of infected cells, as detected by immunofluorescence in the noncultured mononuclear cell samples, was 1 to 5/300,000, and was usually > 10/300,000 in the cultured cell samples. Virus was isolated from all postinoculation blood samples obtained from 4 heifers that were seronegative at the time of inoculation, but was not isolated from any of the preinoculation samples, or from any of the postinoculation samples obtained from 2 heifers that were seropositive at the time of inoculation. When virus isolation was attempted from separated mononuclear cells in 2 heifers, 43.7% of the noncultured and 87.5% of the cultured samples had positive results.     

Elevated carbon dioxide and temperature effects on rice yield,leaf greenness,and phenological stages duration

The present field experiment was conducted during two consecutive cropping seasons in central Portugal to study the effects of simultaneous elevation of carbon dioxide concentration ([CO₂]) (550 μmol mol^?1) and air temperature (+2–3 °C) on japonica rice (Oryza sativa L. “Ariete”) yield, crop duration, and SPAD-values across the seasons compared with the open-field condition. Open-top chambers were used in the field to assess the effect of elevated air temperature alone or the combined effect of elevated air temperature and atmospheric [CO₂]. Open-field condition was assessed with randomized plots under ambient air temperature and actual atmospheric [CO₂] (average 382 μmol mol^?1). Results obtained showed that the rice “Ariete” had a moderate high yielding under open-field condition, but was susceptible to air temperature rise of +2–3 °C under controlled conditions resulting in reduction of grain yield. The combined increase of atmospheric [CO₂] with elevated air temperature compensated for the negative effect of temperature rise alone and crop yield was higher than in the open-field. SPAD-readings at reproductive stage explained by more than 60 % variation the straw dry matter, but this finding requires further studies for consolidation. It can be concluded that potential increase in air temperature may limit rice yield in the near future under Mediterranean areas where climate change scenario poses a serious threat, but long term field experiments are required.     

Species proportions by area in mixtures of Scots pine (<Emphasis Type="Italic">Pinus sylvestris</Emphasis> L.) and European beech (<Emphasis Type="Italic">Fagus sylvatica</Emphasis> L.)

Scots pine (Pinus sylvestris L.) and European beech (Fagus sylvatica L.) dominate many of the European forest stands. Also, mixtures of European beech and Scots pine more or less occur over all European countries, but have been scarcely investigated. The area occupied by each species is of high relevance, especially for growth evaluation and comparison of different species in mixed and monospecific stands. Thus, we studied different methods to describe species proportions and their definition as proportion by area. 25 triplets consisting of mixed and monospecific stands were established across Europe ranging from Lithuania to Spain in northern to southern direction and from Bulgaria to Belgium in eastern to western direction. On stand level, the conclusive method for estimating the species proportion as a fraction of the stand area relates the observed density (tree number or basal area) to its potential. This stand-level estimation makes use of the potential from comparable neighboring monospecific stands or from maximum density lines derived from other data, e.g. forest inventories or permanent observations plots. At tree level, the fraction of the stand area occupied by a species can be derived from the proportions of their crown projection area or of their leaf area. The estimates of the potentials obtained from neighboring monospecific stands, especially in older stands, were poorer than those from the maximum density line depending on the Martonne aridity index. Therefore, the stand-level method in combination with the Martonne aridity index for potential densities can be highly recommended. The species’ proportions estimated with this method are best approximated by the proportions of the species’ leaf areas. In forest practice, the most commonly applied method is an ocular estimation of the proportions by crown projection area. Even though the proportions of pine were calculated here by measuring crown projection areas in the field, we found this method to underestimate the proportion by 25% compared to the stand-level approach.     

全日制放牧BMY牛的活体采卵-体外胚胎生产-胚胎移植研究

为建立BMY牛的活体采卵(OPU)-体外胚胎生产(IVP)-胚胎移植(ET)快速扩繁技术体系,从人工草地全放牧牛群中选择健康的经产空怀BMY牛作为供体(n=14)集中OPU一次;卵母细胞经TCM-199体外成熟培养(IVM)、Fert-TALP液体外受精(IVF),受精卵用合成输卵管液(SOF)体外培养(IVC)生产胚胎;BMY牛受体(n=81)用CUE-MATETM孕酮阴道栓+EB+FSH+PG方法同期发情处理,对黄体合格的移植OPU-IVP来源鲜胚。研究结果表明:①OPU头均获卵母细胞23.50枚,获10枚以上卵母细胞的供体占85.7%;IVP的平均囊胚数和可用胚数分别为5.21和4.00枚;OPU前8～9d卵巢上有黄体(CL)的供体,头均获卵母细胞数及IVP的囊胚数、可移植胚数、囊胚率和可移植胚率分别比对照组高7.28枚(P<0.05)、7.29枚(P<0.05)、6.00枚(P<0.05)、27.3%(P<0.01)和23.2%(P<0.01);②受体黄体合格率69.1%(56/81),胚胎移植妊娠率37.5%(21/56),产犊率35.7%(20/56);③受体在胚胎移植时注射GnRH,其妊娠率比对照组高16.2%(P>0.05)。结果显示,BMY母牛具有良好的OPU潜力,但个体间差异较大;可通过严格供体选择及改善IVP技术等措施,实现OPU-IVP效率最大化。CUE-MATETM+EB+FSH+PG同期发情处理方法适于在牛规模化胚胎移植(ET)和人工授精(AI)中应用。综合应用OPU、IVP、同期发情和ET技术是加快优良BMY牛扩繁的重要途径之一。     

Aortic rupture causing cardiac tamponade in a 24‐day‐old Friesian colt with concurrent colonic Chlamydiosis and Balantidiasis

A 24‐day‐old Friesian colt died suddenly and a physical examination the morning the foal died showed no abnormalities and serum IgG levels >8.0 g/l. Necropsy examination revealed haemopericardium and a 2 cm transverse tear at the root of the aorta. The foal was also found to have Chlamydophila spp. in the epithelium and Balantidium coli on the mucosal surface of the large colon. An aortic rupture is a novel finding in a foal, colonic Chlamydiosis has not been previously reported in horses and Balantidium coli has not been reported in equids in North America.     

Serobiotypes and virulence genes of Escherichia coli strains isolated from diarrheic and healthy rabbits in Brazil

A total of 178 Escherichia coli isolates from diarrheic and healthy rabbits in the S?o Paulo State (Brazil) were serobiotyped and investigated by PCR for the presence of virulence genes. Among the 90 (50.6%) isolates which possessed the eae gene, 74 were from diarrheic animals and all but one encoded intimin beta. Sixty five (72.2%) of the eae+ isolates had insertion of the locus of enterocyte effacement locus in the pheU locus, 11 (12.2%) in the selC and 14 (15.6%) did not insert in either of these loci. All isolates were negative for genes of the E. coli enterotoxins, Stx1, Stx2, CNF1, CNF2 and EHEC hemolysin. The O132:H2 serotype was dominant, being present in 63 isolates (70%) of the 90 eae+ isolates, and 57 of the 63 isolates of this serotype belonged to biotype 30. PCR detected the gene for AF/R2 fimbriae in 75 (83.3%) of the 90 eae+ isolates. Adherence to HeLa cells was best detected following 6h incubation and a positive fluorescence actin staining (FAS) test was given by 52 isolates. These data show that isolates of E. coli associated with diarrhea in rabbits in Brazil possess the genotype and phenotype typically associated with rabbit enteropathogenic E. coli (EPEC). We conclude that EPEC that possess the eae gene are a common cause of diarrhea in Brazilian rabbit farms and that the pathogenic eae+ AF/R2+ isolates of O132:H2:B30 serobiotype are especially predominant.     

Variability in in vitro macrophage activation by commercially diverse bulk echinacea plant material is predominantly due to bacterial lipoproteins and lipopolysaccharides

We previously reported that the majority of in vitro monocyte/macrophage activation exhibited by extracts of Echinacea and other botanicals depends upon bacterial lipopolysaccharides and Braun-type bacterial lipoproteins. We determined the contribution made by these bacterial components to the overall immune-enhancing activity detected in E. purpurea and E. angustifolia bulk root and aerial material obtained from six major growers/suppliers in North America. Substantial variation in activity (up to 200-fold) was observed in extracts of these materials when tested in two monocyte/macrophage cell lines. The majority of activity was negated by treatment with agents that target bacterial lipoproteins (lipoprotein lipase) and lipopolysaccharides (polymyxin B). Experiments comparing the activity of freeze-dried, freshly harvested Echinacea plants to those harvested and dried using various commercially relevant conditions suggest that postharvesting procedures do not substantially contribute to the variation observed in the commercial material.