Genotypic variability and mode of action of Colorado potato beetle (Coleoptera: Chrysomelidae) resistance in seven Solanum species

Accessions from seven wild Solanum species were evaluated in the field for resistance to the Colorado potato beetle, Leptinotarsa decemlineata (Say). The multivariate insect population density data were analyzed using factor analysis. The factors extracted corresponded to relevant phases of the insect's life cycle and provided information on the mode of resistance (antixenosis and antibiosis) of the plant species. S. berthaultii, S. capsicibaccatum, S. jamesii, S. pinnatisectum, and S. trifidum demonstrated both antixenosis and antibiosis but expressed different levels of resistance. The mode of resistance of S. polyadenium seemed to be antibiosis and that of S. tarijense antixenosis. Genetic variability and heritability of insect resistance traits within accessions was trivial or inconsistent for all Solanum species studied.     

Identification of acetic acid bacteria isolated from Indonesian sources,especially of isolates classified in the genus Gluconobacter

Sixty-four strains of acetic acid bacteria were isolated from Indonesian sources such as fruits, flowers, and fermented foods by the enrichment culture at pH 3.5. Forty-five strains were routinely identified as Acetobacter strains because of their oxidation of acetate and lactate to carbon dioxide and water and their Q-9 isoprenolog, corresponding to 70% of all the 64 acetic acid bacteria isolated. Eight isolates were identified as Gluconacetobacter strains because of their oxidation of acetate and lactate and their Q-10 isoprenolog, occupying 13% of all the isolates. The remaining 11 isolates, accommodated in the genus Gluconobacter because of no oxidation of acetate and lactate and because of their Q-10 isoprenolog, accounted for 17% of all the isolates. They were divided into two groups based on DNA base compositions. One comprised the seven isolates, which had high G1C contents of DNA ranging from 60.3 to 63.5 mol% and of which DNAs hybridized with that of the type strain of Gluconobacter oxydans at values of 64-94% of DNA relatedness. The other comprised the remaining four isolates, which had low G+C contents of DNA ranging from 57.5 to 57.7 mol% and of which DNAs hybridized with that of the type strain of Gluconobacter frateurii at values of 63-77% of DNA relatedness. The high values of DNA relatedness, 84 to 96%, were obtained between the type strains of Gluconobacter cerinus and Gluconobacter asaii.     

Arabidopsis Sec21p and Sec23p homologs. Probable coat proteins of plant COP-coated vesicles

Intracellular protein transport between the endoplasmic reticulum (ER) and the Golgi apparatus and within the Golgi apparatus is facilitated by COP (coat protein)-coated vesicles. Their existence in plant cells has not yet been demonstrated, although the GTP-binding proteins required for coat formation have been identified. We have generated antisera against glutathione-S-transferase-fusion proteins prepared with cDNAs encoding the Arabidopsis Sec21p and Sec23p homologs (AtSec21p and AtSec23p, respectively). The former is a constituent of the COPI vesicle coatomer, and the latter is part of the Sec23/24p dimeric complex of the COPII vesicle coat. Cauliflower (Brassica oleracea) inflorescence homogenates were probed with these antibodies and demonstrated the presence of AtSec21p and AtSec23p antigens in both the cytosol and membrane fractions of the cell. The membrane-associated forms of both antigens can be solubilized by treatments typical for extrinsic proteins. The amounts of the cytosolic antigens relative to the membrane-bound forms increase after cold treatment, and the two antigens belong to different protein complexes with molecular sizes comparable to the corresponding nonplant coat proteins. Sucrose-density-gradient centrifugation of microsomal cell membranes from cauliflower suggests that, although AtSec23p seems to be preferentially associated with ER membranes, AtSec21p appears to be bound to both the ER and the Golgi membranes. This could be in agreement with the notion that COPII vesicles are formed at the ER, whereas COPI vesicles can be made by both Golgi and ER membranes. Both AtSec21p and AtSec23p antigens were detected on membranes equilibrating at sucrose densities equivalent to those typical for in vitro-induced COP vesicles from animal and yeast systems. Therefore, a further purification of the putative plant COP vesicles was undertaken.     

Influence of liquid medium and surface morphology on the response of QCM during immobilization and hybridization of short oligonucleotides

With the goal of developing a quartz crystal microbalance (QCM)-based DNA sensor, we have conducted an in situ QCM study along with fluorescence measurements using oligonucleotides (15-mer) as a model single-stranded DNA (ss-DNA) in two different aqueous buffer solutions; the sequence of 15-mer is a part of iduronate-2-sulphate exon whose mutation is known to cause Hunter syndrome, and the 15-mer is thiolated to be immobilized on the Au-coated quartz substrate. The fluorescence data indicate that the initial immobilization as well as the subsequent hybridization with a complementary strand is hardly dependent on the kind of buffer solution. In contrast, the mass increases deducible from the decrease of QCM frequency via the Sauerbrey equation are 2.7-6.2 and 3.0-4.4 times larger than the actual mass increases, as reflected in the fluorescence measurements, for the immobilization and the subsequent hybridization processes, respectively. Such an overestimation is attributed to the trapping of solvent as well as the formation of quite a rigid hydration layer associated with the higher viscosities and/or densities of the buffer solutions. Another noteworthy observation is the excessively large frequency change that occurs when the gold electrode is deposited in advance with Au nanoparticles. This clearly illustrates that the QCM detection of DNA hybridization is also affected greatly by the surface morphology of the electrode. These enlarged signals are altogether presumed to be advantageous when using a QCM system as an in situ probing device in DNA sensors.     

肾素-血管紧张素系统在调节肾脏活动和慢性肾功能不全中的作用

一、肾内RAS的组成、生物学特征及肾内分布;(一)有关RAS的研究进展;(二)肾脏组织局部的RAS;(三)AngⅡ受体的亚型及其在肾内的分布;二、AngⅡ对肾脏血流动力学的影响;三、AngⅡ对肾脏的非血流动力学效应;(一)AngⅡ的促生长作用及促纤维生成效应;(二)AngⅡ作为促炎症因子的作用;四、有关RAS在肾功能不全中的临床研究     

Signal detection theory applied to three visual search tasks--identification, yes/no detection and localization

Adding distracters to a display impairs performance on visual tasks (i.e. the set-size effect). While keeping the display characteristics constant, we investigated this effect in three tasks: 2 target identification, yes-no detection with 2 targets, and 8-alternative localization. A Signal Detection Theory (SDT) model, tailored for each task, accounts for the set-size effects observed in identification and localization tasks, and slightly under-predicts the set-size effect in a detection task. Given that sensitivity varies as a function of spatial frequency (SF), we measured performance in each of these three tasks in neutral and peripheral precue conditions for each of six spatial frequencies (0.5-12 cpd). For all spatial frequencies tested, performance on the three tasks decreased as set size increased in the neutral precue condition, and the peripheral precue reduced the effect. Larger set-size effects were observed at low SFs in the identification and localization tasks. This effect can be described using the SDT model, but was not predicted by it. For each of these tasks we also established the extent to which covert attention modulates performance across a range of set sizes. A peripheral precue substantially diminished the set-size effect and improved performance, even at set size 1. These results provide support for distracter exclusion, and suggest that signal enhancement may also be a mechanism by which covert attention can impose its effect.     

HCMV IE2-mediated inhibition of HAT activity downregulates p53 function

Targeting of cellular histone acetyltransferases (HATs) by viral proteins is important in the development of virus-associated diseases. The immediate-early 2 protein (IE2) of human cytomegalovirus (HCMV) binds to the tumor suppressor, p53, and inactivates its functions by unknown mechanisms. Here, we show that IE2 binds to the HAT domain of the p53 coactivators, p300 and CREB-binding protein (CBP), and blocks their acetyltransferase activity on both histones and p53. The minimal HAT inactivation region on IE2 involves the N-terminal 98 amino acids. The in vivo DNA binding of p53 and local histone acetylation on p53-dependent promoters are all reduced by IE2, but not by mutant IE2 proteins that lack the HAT inhibition region. Furthermore, the p53 acetylation site mutant, K320/373/382R, retains both DNA binding and promoter transactivation activity in vivo and these effects are repressed by IE2 as well. Together with the finding that only wild-type IE2 exerts an antiapoptotic effect, our results suggest that HCMV IE2 downregulates p53-dependent gene activation by inhibiting p300/CBP-mediated local histone acetylation and that IE2 may have oncogenic activity.     

Isolation and characterization of a cellulolytic <Emphasis Type="Italic">Geobacillus thermoleovorans</Emphasis> T4 strain from sugar refinery wastewater

A novel, cellulolytic, bacterial thermophilic strain, T4, was isolated from sugar refinery wastewater in southern Taiwan. This isolate, a Gram-negative, motile, aerobically growing sporulating rod, can secrete thermostable endocellulase (endo-1,4--D-glucanase, EC 3.2.1.4) and hydrolyze carboxymethylcellulose (CMC), phosphoric acid-swollen cellulose, Avicel, filter paper, and salicin. When strain T4 was grown in CMC medium, the cellulolytic enzyme activity in culture supernatants was stable up to 70°C. More than 10% of the original activity was still detectable after heating to 100°C with a pH 7.0 for 1 h. Based on 16S rDNA sequence analysis, DNA base composition, phenotypic and physiological characteristics, as well as DNA–DNA hybridization, strain T4 was classified as Geobacillus thermoleovorans T4 (DSM 14791 = CCRC 17200). We also demonstrated that the type species G. stearothermophilus (DSM 22 = ATCC 12980) could hydrolyze amorphous and crystalline (filter paper) celluloses at a rate of 13 and 14%, respectively, in comparison with strain T4.     

N-Acetylcysteine ameliorates lipopolysaccharide-induced organ damage in conscious rats

Lipopolysaccharide is strongly associated with septic shock, leading to multiple organ failure. It can activate monocytes and macrophages to release proinflammatory mediators such as tumor necrosis factor- (TNF-), interleukin-1 (IL-1), and nitric oxide (NO). The present experiments were designed to induce endotoxin shock by an intravenous injection ofKlebsiella pneumoniae lipopolysaccharide (LPS, 10 mg/kg) in conscious rats. Arterial pressure and heart rate (HR) were continuously monitored for 48 h after LPS administration. N-Acetyl-cysteine was used to study its effects on organ damage. Biochemical substances were measured to reflect organ functions. Biochemical factors included blood urea nitrogen (BUN), creatinine (Cre), lactic dehydrogenase (LDH), creatine phosphokinase (CPK), aspartate transferase (GOT), alanine transferase (GPT), TNF-, IL-1, methyl guanidine (MG), and nitrites/nitrates. LPS caused significant increases in blood BUN, Cre, LDH, CPK, GOT, GPT, TNF-, IL-1, MG levels, and HR, as well as a decrease in mean arterial pressure and an elevation of nitrites/nitrates. N-Acetylcysteine suppressed the release of TNF-, IL-1, and MG, but enhanced NO production. These actions ameliorate LPS-induced organ damage in conscious rats. The beneficial effects may suggest a potential chemopreventive effect of this compound in sepsis prevention and treatment.