Purification and characterization of RNA polymerase I from a higher plant.

RNA polymerase I was purified from chromatin isolated from auxin-treated soybean hypocotyl. Purification was achieved by using Agarose A-1.5m gel filtration, DEAE-cellulose, CM-sephadex, and phosphocellulose chromatography, and sucrose density gradient centrifugation. With denatured calf thymus DNA as template, the enzyme has a high specific activity (200-300 nmol/mg/30 min at 28 degrees C) which is comparable to other RNA polymerase I enzymes purified from animals and yeast. While the gel profiles indicate that purification to homogeneity (greater than 90%) may not have been achieved, the enzyme appears to be composed of possibly 7 subunits, several of which are similar to the subunits of yeast RNA polymerase I. The putative subunits and molar ratios are 183 000 (1), 136 000 (1), 50 000 (0.5), 46 000 (0.5), 40 000 (0.5), 33 000 (0.2), and 28 000 (2). The purified enzyme strongly prefers a completely denatured template such as poly(dC).     

Clinical manifestations of taeniasis in Taiwan aborigines.

From 1974 to 1989, a total of 24,500 aborigines at 67 villages in ten mountainous districts/towns in Taiwan were examined for the Taiwan Taenia infection and 12% were found to be infected. In order to define the clinical manifestations of taeniasis caused by the Taiwan Taenia, 1661 aborigines in ten mountainous districts were surveyed. The overall clinical rate was 76%. The clinical rate was highest among Atayal aborigines (81%), followed by Bunun (66%) and Yami (61%) aborgines and lowest among Ami aborigines (40%). Among 1153 infected people, 10% had passed gravid segments in the faeces for less than 1 year, 24% for 1-3 years, 17% for 4-5 years, 23% for 6-10 years, 16% for 11-20 years, 7% for 21-30 years, and 3% over 30 years. Twenty-six occurrences of gastrointestinal and neurological symptoms were reported by 1258 infected persons. Passing proglottides in the faeces (95%) was the most frequent sign, followed by pruritis ani (77%), nausea (46%), abdominal pain (45%), dizziness (42%), increased appetite (30%), headache (26%), etc.     

Reaction mechanism of surfactant‐sensitized chemiluminescence of bis(2,4,6‐trichlorophyenyl) oxalate and hydrogen peroxide induced by gold nanoparticles

The chemiluminescence (CL) of bis(2,4,6‐trichlorophyenyl) oxalate with hydrogen peroxide in the present of cationic surfactant and gold nanoparticles was studied. The CL emission was obviously enhanced in the presence of surfactant at a suitable concentration, with a synergetic catalysis effect exhibited. Different sizes of gold nanoparticles (15 and 50 nm) showed different effects on CL intensity. Mechanisms of the CL reaction and sensitization effect are discussed. Copyright © 2008 John Wiley & Sons, Ltd.     

In vitro propagation of Alstroemeria ‘Alsaan’

Plantlets were regenerated from Alstroemeria Alsaan rhizome tips cultured in vitro on solid and liquid media based on Murashige and Skoog salt formulation. The quality of the cultures was superior when intact rather than longitudinally sliced rhizome tips were used as explants and when a temperature of 8°C rather than 22°C was used at the initiation stage. More roots were produced on rhizome tips containing a rhizome apical meristem than on rhizome sections lacking such a meristem. Most (90%) of the rooted plantlets were successfully acclimatized and developed into true-to-type flowering plants.     

An electron microscopic study of retinal degeneration in Sprague-Dawley rats

Retinal degeneration in untreated, female Sprague-Dawley rats was studied by electron microscopy and horseradish peroxidase tracer technique. The degeneration appeared to have started at a very young age. The severity of the defect varied from a decrease of photoreceptor nuclei to total loss of receptor cells and the pigment epithelium. In mild degeneration some regions of the retinal pigment epithelium became bilayered and the basal plasma membrane became flattened or formed elaborate infoldings. Breaks in Bruch's membrane occurred in severe degeneration. Degeneration of the pigment epithelium allowed permeation of tracer material from the choroid into the retina.     

Characterization ofR. fredii QB1130, a strain effective on commercial soybean cultivars

Summary Two rhizobial strains (QB1130 and C3A) from northeast China were identified asRhizobium fredii on the basis of growth rate, media acidification and growth on a wide range of carbon substrates. The strains were shown to be distinct from USDA 191 on the basis of plasmid number and size. Bothnif and commonnod genes were located on the 295 kb plasmid of strains QB1130 and USDA 191, while onlynif genes were identified on this plasmid in C3A. When used to inoculate four commercial soybean (Glycine max) cultivars, one of the strains (C3A) was found to be ineffective, while the other (QB1130) was at least as effective as USDA 191, a strain ofR. fredii reported to be widely effective on North American cultivars of soybean. Further, QB1130 was capable of more effective nodulation of cowpea or the uncultivated soybean line, Peking, than either USDA 191 or the slow-growingBradyrhizobium japonicum USDA 16. Strain QB1130 should be useful for studies directed at improving symbiotic performance in soybean, or for studies of the comparative physiology and genetics of FG and SG strains on a single host.     

Immunocytochemical studies on prolactin cells in the adenohypophysis of the golden hamster

Mammotrophs or prolactin (PRL) cells were identified in the adenohypophysis of adult golden hamsters by immunocytochemical techniques with a polyclonal anti-PRL, that was proved to be specific to PRL by the dot immunoblotting test. Postembedding immunostaining was performed on Araldite thin sections by immunoperoxidase and immunogold methods. PRL cells were classified into three types according to the different size of the secretory granules. The Type A cells were usually small and angular or oval in shape, and had secretory granules ranging in diameter from 100-230 nm, and showed poorly developed organelles. The Type B and C cells were larger and round or ovoid in shape, contained larger granules, 230-280 nm and 280-570 nm, respectively, and displayed well developed organelles. Immunoreactive PRL cells in the male pituitaries were far less numerous than in the nonpregnant female glands, and were mostly of the Type A and B, whereas in the female the Type C and B cells predominated. In pregnant females, Type C cells became activated and increased in number, while the other two types decreased in proportion. In lactating females, Type A and B cells significantly increased in number at the expense of the Type C cells; meanwhile, the exocytosis of secretory granules was frequently found in all types of PRL cells. The present findings suggest that Type C and B PRL cells, especially the former, are potent in producing and releasing PRL and highly responsive to various physiological stimuli, while Type A cells are probably relatively inert in synthetic activity.     

不同海拔地区种植的水稻地上部干物质的生产和分配

根据1983—1985年“高原水稻高产栽培的生理生态规律研究”中低热的元江(海拔400米左右)、温凉的昆明(约1900米)和冷凉的丽江(约2400米)的资料,以六个处理、十八个小区、三年总平均值,比较了不同海拔地区种植的水稻中地上部干物质生产和分配的总趋势。主要结果如下: 1.全生育期总的干物质生产量以温凉地区最高,低热地区居中,冷凉地区最低。 2.抽穗前干物质生产速率和齐穗期干物重占黄熟期干物重的比例随海拔降低而增加;抽穗期至黄熟期干物质生产速率,以温凉地区最高,低热地区居中,冷凉地区最低,但低热地区低于前期,高海拔地区高于前期,不过冷凉的丽江增加的更多。 3.抽穗前(旗叶完全展开后)叶干重占当时植株总干重的比例,随海拔升高而降低。 4.抽穗期至黄熟期的次库(茎 叶鞘)干重的改变,不同海拔地区种植的水稻表现不同:低热地区减重,温凉地区稍增,冷凉地区明显增加。 5.与高海拔地区种植的水稻相比,在黄熟期低海拔地区的有较高的穗重/总重和穗增重/总增重的比例。另外低海拔地区的穗增重超过总增重。结实率和谷/草比例均随海拔增高而减低。     

NAD-linked aldehyde dehydrogenase for aerobic utilization of L-fucose and L-rhamnose by Escherichia coli.

Mutant analysis revealed that complete utilization of L-fucose and L-rhamnose by Escherichia coli requires the activity of a common NAD-linked aldehyde dehydrogenase which converts L-lactaldehyde to L-lactate. Mutations affecting this activity mapped to the ald locus at min 31, well apart from the fuc genes (min 60) encoding the trunk pathway for L-fucose dissimilation (as well as L-1,2-propanediol oxidoreductase) and the rha genes (min 88) encoding the trunk pathway for L-rhamnose dissimilation. Mutants that grow on L-1,2-propanediol as a carbon and energy source also depend on the ald gene product for the conversion of L-lactaldehyde to L-lactate.     

Characterization of the Erwinia carotovora pelB gene and its product pectate lyase.

The pelB gene encodes pectate lyase B, one of three pectate lyases identified in Erwinia carotovora EC. Pectate lyase B was purified from Escherichia coli containing the pelB gene on a recombinant plasmid. The activity of the protein was optimal at a pH of 8.3. The amino acid composition, N-terminal amino acid sequence, and C-terminal peptide sequence were determined and compared with the polypeptide sequence deduced from the DNA sequence of pelB. Purified pectate lyase B started at amino acid 23 of the predicted sequence, suggesting that a 22-amino-acid leader peptide had been removed. Pectate lyase B of E. carotovora EC and pectate lyase B of E. chrysanthemi EC16 contain 352 and 353 amino acids, respectively (N. T. Keen, S. Tanaki, W. Belser, D. Dahlbeck, and B. Staskawicz, J. Bacteriol. 168:595-606, 1986). The two proteins are 72% homologous on the basis of DNA sequence data, and 75% of the amino acids are identical.