摘要：
Ethylene (ET) is a signaling molecule that coordinates responses to a multitude of biotic and abiotic stresses in plants. This is a review of recent advances in our understanding of the regulation of ET biosynthesis, perception, signal transduction, and the cross-talk between the transduction pathways of ET and other signaling molecules such as jasmonates, salicylic acid and abscisic acid in plant defense against biotic and abiotic stresses. (c) 2006 SAAB. Published by Elsevier B.V. All rights reserved.
摘要：
Lysosomal destabilization is a critical event not only for the organelle but also for living cells. However, what factors can affect lysosomal stability is not fully studied. In this work, the effects of phosphatidic acid (PA) on the lysosomal integrity were investigated. Through the measurements of lysosomal beta-hexosaminidase free activity, intralysosomal pH, leakage of lysosomal protons and lysosomal latency loss in hypotonic sucrose medium, we established that PA could increase the lysosomal permeability to K+ and H+, and enhance the lysosomal osmotic sensitivity. Treatment of lysosomes with PA promoted entry of K+ into the organelle via K+/H+ exchange, which could produce osmotic stresses and osmotically destabilize the lysosomes. In addition, PA-induced increase in the lysosomal osmotic sensitivity caused the lysosomes to become more liable to destabilization in osmotic shocks. The results suggest that PA may play a role in the lysosomal destabilization.
摘要：
This paper aimed to study the toxicity of arsanilic acid on rat primary hepatocytes in vitro by a modification of the perfusion method. The conditions included concentrations of 0, 1.085, 10.85, 108.5, 1,085 and 10,850 mg/kg arsanilic acid in RPMI 1,640 medium at rat hepatocytes plates respectively, each group had five repeats at 37°C for 48 h. The rat primary hepatocytes survival ratio, DNA Ladder, activities of glutathione peroxidase (GSH-px), superoxide dismutase (SOD) and catalase (CAT) in hepatocytes, activity of SOD in the medium and the expression of gene bax in hepatocytes were measured at 12 h, 24 h and 48 h respectively. The results showed that arsanilic acid decreased the activities of GSH-px and SOD, and increased the activity of CAT in all dosages, and affected as positive DNA ladder. Although the SOD activities of both hepatocytes and medium in 1.085 mg/L arsanilic acid were significantly lower than the base line at 12 h, CAT activity in 10.85 mg/L arsanilic acid was significantly higher than the base line at 48 h, and all of the DNA ladders were positive, which means 1.085 mg/L arsanilic acid induced apoptosis at 24 h. The gene expression of bax was significantly upregulated in 1.085 mg/L arsanilic acid or higher for 24 h. The parameters in 1,085 mg/L and 10,850 mg/L arsanilic acid had more severe changes than the others at any time indicating that these levels of arsanilic acid were toxic hazards for hepatocyte survival. It was concluded that arsanilic acid induced a dosage- and time-dependent gene expression of bax, 1.085 mg/L arsanilic acid could be involved in rat liver cell apoptosis at 24 h. Arsanilic acid as additives in livestock feed could present potential toxic implications for farm animals.
摘要：
Platinum nanowire (PtNW) can be grown by electrodeposition in polycarbonate membrane, with the average diameter of the nanowires about 250 nm. The PtNW and multiwalled carbon nanotubes (CNT) are then dispersed into chitosan (CHIT) solution. The resulting PtNW-CNT-CHIT material brings new capabilities for electrochemical devices by using the synergistic action of the electrocatalytic activity of PtNW and CNT. By dropping the PtNW-CNT-CHIT film onto the glassy carbon (GC) electrode surface, and after evaporation an amperometric sensor for the determination of indole-3-acetic acid (IAA) was developed. The oxidation current of IAA increased significantly at the PtNW-CNT-CHIT film coated GC electrode, in contrast to that at the CNT-CHIT modified GC. The linear response of the sensor is from 50 ng/ml to 50 μg/ml with a detection limit of 25 ng/mL.
摘要：
The two minor dsRNA bands, previously detected in symptomatic leaves of Raphanus sativus-root cv. Yidianhong [corrected] were subjected to further analysis. cDNA cloning and sequencing revealed that the smaller of the two dsRNA bands is actually a doublet consisting of two co-migrating dsRNA segments and the resulting three segments were designated as RasR 3, RasR 4, and RasR 5. RasR 3 was 1717 bp in length and potentially encoded a protein of about 55.3 kDa, containing all of the six conserved motifs shared by the RNA dependent RNA polymerases of members of the family Partitiviridae. RasR 4 and RasR 5, which co-migrated in the 5% polyacrylamide gel, were 1521 and 1485 bp in length and each encoded a putative protein of unknown function. Their molecular masses, as calculated from the deduced amino acid, were 38.2 and 38.8 kDa, respectively. The 5' UTRs of all three segments shared regions of high sequence similarities, but were distinct from those of the RasR 1 and RasR 2. Taken together, these results along with those described in the previous report, suggest that more than one partitivirus was co-infecting radish leaves.
摘要：
In this study, we investigated the effects of arachidonic acid, a PLA2-produced lipid metabolite, on the lysosomal permeability, osmotic sensitivity and stability. Through the measurements of lysosomal β-hexosaminidase free activity, membrane potential, intralysosomal pH, and lysosomal latency loss in hypotonic sucrose medium, we established that arachidonic acid could increase the lysosomal permeability to both potassium ions and protons, and enhance the lysosomal osmotic sensitivity. As a result, the fatty-acid-promoted entry of potassium ions into the lysosomes via K+/H+ exchange, which could produce osmotic imbalance across their membranes and osmotically destabilize the lysosomes. In addition, the enhancement of lysosomal osmotic sensitivity caused the lysosomes to become more liable to destabilization in osmotic shock. The results suggest that arachidonic acid may play a role in the lysosomal destabilization.
摘要：
Post-translational modification is central to protein stability and to the modulation of protein activity. Various types of protein modification, such as phosphorylation, methylation, acetylation, myristoylation, glycosylation, and ubiquitination, have been reported. Among them, ubiquitination distinguishes itself from others in that most of the ubiquitinated proteins are targeted to the 26S proteasome for degradation. The ubiquitin/26S proteasome system constitutes the major protein degradation pathway in the cell. In recent years, the importance of the ubiquitination machinery in the control of numerous eukaryotic cellular functions has been increasingly appreciated. Increasing number of E3 ubiquitin ligases and their substrates, including a variety of essential cellular regulators have been identified. Studies in the past several years have revealed that the ubiquitination system is important for a broad range of plant developmental processes and responses to abiotic and biotic stresses. This review discusses recent advances in the functional analysis of ubiquitination-associated proteins from plants and pathogens that play important roles in plant-microbe interactions.
摘要：
A mini-plot field experiment was conducted on a loamy clay Oxisol to compare and evaluate P absorption and transfer in plant organs and P movement in soil profile at three P application depths under the soybean-citrus intercropping versus the monoculture using a 32P tracer technique. Total P absorption (Pt) by soybean and P accumulation (Pa) in soybean organs decreased significantly (P < 0.05) under the intercropping in contrast to the monoculture. With intercropping, when 32P was applied in topsoil (15 cm soil layer), total 32P absorption (32Pt) in soybeans was significantly lower (P < 0.05), but when 32P was applied to deeper soil layers (35 or 55 cm soil layer), 32Pt in soybeans was significantly greater (P < 0.05). The percentage of P in leaves to total P (Pa/Pt) and 32P in leaves to total 32P (32Pa/32Pt) for soybean were ≥ 25% and those of root ≥ 12%. When P was applied in topsoil and 55 cm soil layer, no significant differences were found between intercropping and monoculture for Pt of citrus. The P absorbed by citrus was transferred rapidly to the growing organs of aboveground during the experiment, and the speed of transferring to the growing organs slowed when P was applied to the deeper soil layers. In intercropping, P mobility was heightened in the soil profile, and P in deeper soil layers moved up to topsoil more rapidly.
摘要：
Solvent extraction study of cobalt and nickel were carried out from a chloride solution with a high ratio of Co to Ni using the sodium salt of PC88A as extractant diluted in kerosene. The solution was generated in batches by leaching a tungsten super alloy scraps. The results show that extraction rate of metal ions increases with increase of aqueous phase pH value. The pH0.5 value difference of 1.40 with PC88A indicates the possible separation of cobalt and nickel. Increase of the concentration of the solvent can enhance the percentage extraction of both metal ions. Improvement of temperature is beneficial to extraction separation of cobalt and nickel. Extraction and stripping processes were also studied in a cross-current solvent extraction unit and the results were also given.
作者机构：
[Wang, HB] Department of Environmental Sciences and Engineering, Hunan Agricultural University, Changsha 410128, China;[Xue, ND] State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China, Department of Environmental Sciences and Engineering, Hunan Agricultural University, Changsha 410128, China;[Xu, XB] State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
通讯机构：
[Xu, XB ] ;Chinese Acad Sci, State Key Lab Environm Chem & Ecotoxicol, Ecoenvironm Sci Res Ctr, Beijing 100085, Peoples R China.
摘要：
Background on the generation of the problems of endocrine disrupting pesticides (EDPs) in aquatic environment, characteristics of EDPs, adverse effects and their effect mechanism of EDPs on human and wildlife, the transportation and degradation pathways of EDPs in water and analysis methods of EDPs in water were reviewed. The importance of EDPs in water should be attached to adverse effects on wildlife and human health. It was advised to establish research programs on EDPs in aquatic environment especially in water supply source.
摘要：
The SKP1-Cullin/Cdc53-F-box protein ubiquitin ligases (SCF) target many important regulatory proteins for degradation and play vital roles in diverse cellular processes. In Arabidopsis there are 11 Cullin members (AtCUL). AtCUL1 was demonstrated to assemble into SCF complexes containing COI1, an F-box protein required for response to jasmonates (JA) that regulate plant fertility and defense responses. It is not clear whether other Cullins also associate with COI1 to form SCF complexes, thus, it is unknown whether AtCUL1, or another Cullin that assembles into SCFCOI1 (even perhaps two or more functionally redundant Cullins), plays a major role in JA signaling. We present genetic and physiological data to directly demonstrate that AtCUL1 is necessary for normal JA responses. The homozygous AtCUL1 mutants axr6-1 and axr6-2, the heterozygous mutants axr6/AXR6, and transgenic plants expressing mutant AtCUL1 proteins containing a single amino acid substitution from phenylalanine-111 to valine, all exhibit reduced responses to JA. We also demonstrate that ax6 enhances the effect of coi1 on JA responses, implying a genetic interaction between COI1 and AtCUL1 in JA signaling. Furthermore, we show that the point mutations in AtCUL1 affect the assembly of COI1 into SCF, thus attenuating SCFCOI1 formation.
