Detection of luciferase gene sequences in nonluminescent bacteria from the Chesapeake Bay

Washed excised roots of rice (Oryza sativa) produced H(2), CH(4) and fatty acids (millimolar concentrations of acetate, propionate, butyrate; micromolar concentrations of isovalerate, valerate) when incubated under anoxic conditions. Surface sterilization of the root material resulted in the inactivation of the production of CH(4), a strong reduction of the production of fatty acids and a transient (75 h) but complete inhibition of the production of H(2). Radioactive bicarbonate was incorporated into CH(4), acetate, propionate and butyrate. About 20-40% of the fatty acid carbon originated from CO(2) reduction. In the presence of phosphate, CH(4) was exclusively produced from H(2)/CO(2), since phosphate selectively inhibited acetoclastic methanogenesis. Acetoclastic methanogenesis was also selectively inhibited by methyl fluoride, while chloroform or 2-bromoethane sulfonate inhibited CH(4) production completely. Production of CH(4), acetate, propionate and butyrate from H(2)/CO(2) was always exergonic with Gibbs free energies <-20 kJ mol(-1) product. Chloroform inhibited the production of acetate and the incorporation of radioactive CO(2) into acetate. Simultaneously, H(2) was no longer consumed and accumulated, indicating that acetate was produced from H(2)/CO(2). Chloroform also resulted in increased production of propionate and butyrate whose formation from CO(2) became more exergonic upon addition of chloroform. Nevertheless, the incorporation of radioactive CO(2) into propionate and butyrate was inhibited by chloroform. The accumulation of propionate and butyrate in the presence of chloroform probably occurred by fermentation of organic matter, rather than by reduction of acetate and CO(2). [U-(14)C]Glucose was indeed converted to acetate, propionate, butyrate, CO(2) and CH(4). Radioactive acetate, CO(2) and CH(4) were also products of the degradation of [U-(14)C]cellulose and [U-(14)C]xylose. Addition of chloroform and methyl fluoride did not affect the product spectrum of [U-(14)C]glucose degradation. The application of combinations of selective inhibitors may be useful to elucidate anaerobic metabolic pathways in mixed microbial cultures and natural microbial communities.     

Stage-specific induction of DNA methyltransferases in olfactory receptor neuron development

DNA methylation-dependent gene silencing, mediated by DNA methyltransferases (DNMTs), is essential for normal mammalian development and its dysregulation has been implicated in neurodevelopmental disorders. Despite this, little is known about DNMTs in the developing or mature nervous system. Here, we show that DNMT1, 3a and 3b are expressed at discrete developmental stages in the olfactory neuron lineage, coincident with key shifts in developmental gene expression. DNMT1 is induced in cycling progenitors and is retained in post-mitotic olfactory receptor neurons (ORNs). DNMT3b is restricted to mitotic olfactory progenitors, whereas DNMT3a is expressed only in post-mitotic immature neurons prior to ORN terminal maturation, coincident with histone deacetylase 2 (HDAC2), a key downstream effector of methylation-dependent chromatin condensation. Similar stage-specific expression of DNMT3b and 3a was also found in other developing sensory and CNS neurons. This suggests that progressive lineage restriction regulated by methylation-dependent silencing could be a highly conserved mechanism shared by multiple lineages in the developing nervous system.     

Identification of jasmonic acid and its methyl ester as gum-inducing factors in tulips

The purpose of this study was to identify endogenous factors that induce gummosis and to show their role in gummosis in tulip (Tulipa gesneriana L. cv. Apeldoorn) stems. Using procedures to detect endogenous factors that induce gum in the stem of tulips, jasmonic acid (JA) and methyl jasmonate (JA-Me) were successfully identified using gas–liquid chromatography–mass spectrometry. Total amounts of JA and JA-Me designated as jasmonates in tulip stems were also estimated at about 70–80 ng/g fresh weight, using deuterium-labeled jasmonates as internal standards. The application of JA and JA-Me as lanolin pastes substantially induced gums in tulip stems with ethylene production. The application of ethephon, an ethylene-generating compound, however, induced no gummosis although it slightly affected jasmonate content in tulip stems. These results strongly suggest that JA and JA-Me are endogenous factors that induce gummosis in tulip stems.     

Identification of nuclear type II [(3)H]estradiol binding sites as histone H4

[3H]Luteolin binds covalently to uterine nuclear type II sites [B. Markaverich, K. Shoulars, M.A. Alejandro, T. Brown, Steroids 66 (2001) 707] and was used to identify this protein(s). SDS-PAGE analyses of [3H]luteolin-labeled type II site preparations revealed specific binding to 11- and 35-kDa proteins. The 11-kDa protein was identified as histone H4 by amino acid sequencing. Western blotting confirmed that the 11- and 35-kDa proteins were acetylated forms of histone H4. Anti-histone H4 antibodies (but not H2A, H2B, or H3 antibodies) quantitatively immunoadsorbed type II binding sites from nuclear extracts. Binding analyses by [3H]estradiol exchange, using luteolin as a competitor, detected specific type II binding activity to histone H4 (but not histones H2A, H2B, or H3) generated in a rabbit reticulocyte lysate translation system and confirmed that histone H4 is the type II site.     

石油添加剂甲基叔丁基醚的污染治理技术研究进展

甲基叔丁基醚是一种石油添加剂,广泛应用于中高档汽油中.其对环境造成的污染和对人体健康造成的危害已日益引起人们的高度重视.本文综述了近年来国外有关甲基叔丁基醚的污染治理技术研究进展,主要是高级氧化技术和微生物降解.已用于处理甲基叔丁基醚的高级氧化技术包括;多相光催化氧化法、紫外光加强的过氧化氢氧化法、臭氧法与臭氧-过氧化氢联合氧化法、超声法与超声-臭氧联合氧化法、芬顿法与光芬顿氧化法、氧气的还原性活化和水的γ射线辐射.微生物降解主要涉及有氧代谢和无氧代谢两大途径.     

A simple method of the preparation of 2′-O-Methyladenosine Methylation of adenosine with methyl iodide in anhydrous alkaline medium

A simple and effective method of the methylation on the 2′-O position of adenosine is described. Adenosine is treated with CH₃I in an anhydrous alkaline medium at 0°C for 4 h. The major products of this reaction are monomethylated adenosine at either the 2′-O or 3′-O position (total of 64%) and the side products are dimethylated adenosine (2′,3′-O-dimethyladenosi, 21%, and N⁶-2′-O-dimethyladenosine, 11%). The ratio of 2′-O- and 3′-O-methyladenosine has been found to be 8 to 1. Therefore, this reaction preferentially favors the synthesis of 2′-O-methyladenosine. The monomethylated adenosine is isolated from reaction mixture by a silica gel column chromatography. Then the pure 2′-O-methyladenosine can be separated by crystallization in ethanol from the mixture of 2′-O and 3′-O-methylated isomers. The overall yield of 2′-O-methyladenosine is 42%.     

Combination of biosorption and photodegradation to remove methyl orange from aqueous solutions

In this study, metal ion‐modified biomass of waste beer yeast was prepared to improve its adsorption capacity for an anionic dye: methyl orange. The adsorption capacities of Fe³⁺‐, Mg²⁺‐, Ca²⁺,‐ and Na⁺‐modified biomass preparations for methyl orange were 90.8, 51.3, 23.0, and 20.6 mg/g, which were 30, 17, 8, and 7 times that of the unmodified biomass, respectively. Adsorption isotherm experiments showed that the Freundlich model gave better fits than the Langmuir model for methyl orange adsorption on Fe³⁺‐, Mg²⁺‐, Ca²⁺‐modified and unmodified biomass, whereas on Na⁺‐modified biomass the Langmuir model gave better fits. The sorption and desorption kinetics of methyl orange on Fe³⁺‐ and Mg²⁺‐modified biomass both fitted well to the pseudo‐second‐order kinetic models, with R≥0.998, and the desorption processes in NaOH solution (pH 12) were very fast in attaining equilibrium, i.e. within 15 min. In order to avoid secondary pollution, the eluent containing the desorbed methyl orange was treated with a photocatalyst: P25. After that, the eluent could be reused, and thus saving a large volume of eluent.     

Methyl jasmonate ameliorates lead toxicity in Oryza sativa by modulating chlorophyll metabolism,antioxidative capacity and metal translocation

Lead (Pb) not only negatively alters plant growth and yield but may also have potentially toxic risks to human health. Nevertheless, the interaction between rice (Oryza sativa L.) plants and the molecular cell dynamics induced by lead-methyl jasmonate (MJ) remains unknown. Here, plants were hydroponically exposed to Pb (150 and 300 µM) alone or in combination with 0.5 and 1 µM MJ. The application of MJ modulated the expression of the HMAs, PCS1, PCS2 and ABCC1 genes, thereby immobilizing the Pb in the roots and lessening its translocation to the aerial parts of the rice plant. The supplementation of MJ improved the growth and yield of Pb-stressed rice by adjusting the proline and chlorophyll metabolism, increasing the phytochelatins (PCs) accumulation and diminishing the accumulation of Pb in the shoots. the application of MJ alleviated the oxidative stress of rice plants exposed to Pb toxicity by enhancing the activity of antioxidant enzymes and enzymes of the glyoxalase system (glyoxalase I and II) and decreasing the endogenous levels of malondialdehyde (MDA), hydrogen peroxide (H₂O₂) and methylglyoxal (MG). Therefore, the results of the present study could provide a molecular insight and cellular interplay scheme for the development of a promising strategy in Pb-contaminated areas to produce healthy food.     

Differential expression profile of membrane proteins in zebrafish (Danio rerio) brain exposed to methyl parathion

Methyl parathion (MP) is a widely used organophosphorus pesticide, which has been related to a broad spectrum of toxic effects on environmental organisms. The present study investigated the changes in the protein profile of enriched membrane fraction from zebrafish (Danio rerio) brain exposed to three concentrations (0.5, 1 and 2 mg/L) of MP. 2-DE revealed that the abundance of 21 protein spots was significantly changed by MP stress. By matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and database search, 16 protein spots were identified as membrane proteins, among which 8 were down-regulated, while 8 were up-regulated. These proteins are mainly involved in oxidative stress response, signal transduction, metabolism, protein synthesis and degradation, neuroplasticity and regeneration as well as synaptic transmission. These results may aid our understanding of the mechanism of MP-induced neurotoxicity and provide the possibility of the establishment of candidate biomarkers of MP.