Dissociation by Pelota, Hbs1 and ABCE1 of mammalian vacant 80S ribosomes and stalled elongation complexes

No-go decay (NGD) and non-stop decay (NSD) are eukaryotic surveillance mechanisms that target mRNAs on which elongation complexes (ECs) are stalled by, for example, stable secondary structures (NGD) or due to the absence of a stop codon (NSD). Two interacting proteins Dom34(yeast)/Pelota(mammals) and Hbs1, which are paralogues of eRF1 and eRF3, are implicated in these processes. Dom34/Hbs1 were shown to promote dissociation of stalled ECs and release of intact peptidyl-tRNA. Using an in vitro reconstitution approach, we investigated the activities of mammalian Pelota/Hbs1 and report that Pelota/Hbs1 also induced dissociation of ECs and release of peptidyl-tRNA, but only in the presence of ABCE1. Whereas Pelota and ABCE1 were essential, Hbs1 had a stimulatory effect. Importantly, ABCE1/Pelota/Hbs1 dissociated ECs containing only a limited number of mRNA nucleotides downstream of the P-site, which suggests that ABCE1/Pelota/Hbs1 would disassemble NSD complexes stalled at the 3'-end, but not pre-cleavage NGD complexes stalled in the middle of mRNA. ABCE1/Pelota/Hbs1 also dissociated vacant 80S ribosomes, which stimulated 48S complex formation, suggesting that Pelota/Hbs1 have an additional role outside of NGD.     

Environmental Sustainability of Fluid Milk Delivery Systems in the United States

Beverage producers in the United States choose packaging based on cost and consumer preference. Monolayer high‐density polyethylene (HDPE) and gable‐top carton containers have long dominated the U.S. fluid milk market, but pressure for more sustainable packaging is increasing. We present a broad discussion on environmental sustainability of 18 fluid milk containers through life cycle assessment. Because different container types require unique milk processing, distribution, and disposal and incur or avoid milk losses, fluid milk delivery systems (FMDSs) are evaluated, rather than containers in isolation. By assessing FMDSs, a complete measure of containers’ environmental sustainability was obtained. Despite conservative assumptions about milk losses, differences in container size, milk processing, distribution, and container recycling, pair‐wise cradle‐to‐grave comparisons of FMDSs show there are no superior FMDSs. But, 500‐ to 1,000‐milliliter FMDSs are potentially superior to ≥half gallon if they prevent milk losses. Thus, the future of FMDSs in the United States depends on the industry's ability to prevent distribution (12%) and consumption milk losses (20% to 35%). Farm‐gate‐to‐grave comparisons showed that chilled HDPE FMDSs are superior to other plastic and chilled paperboard FMDSs for climate‐change impact, but the result is inconclusive for chilled HDPE to ambient (unrefrigerated) paperboard or plastic pouch FMDS comparisons. Plastic pouch FMDSs show potential to reduce nonrenewable fossil energy, but need to be recyclable. Ambient FMDSs are superior to chilled FMDSs for water depletion. Eight‐ounce paperboard FMDSs are superior to 8‐ounce plastic FMDSs. Thus, alternative FMDSs may improve environmental sustainability of the U.S. postfarm fluid milk supply chain.     

Correlations between characteristics of evoked EEG potentials recorded in a go/no-go paradigm and indices of attention in children

We studied correlations of the parameters of evoked EEG potentials (EPs) with the indices of attention in 30 children (12 years old). The EP were recorded in a two-stimulus go/no-go paradigm; the time of reaction was also measured. The indices of attention were measured using a Burdone test (correction trial) and Schulte’s tables. Optimum characteristics of attention were found in children with high amplitudes of the P2 component, P300 wave, and contingent negative deviation, low amplitudes of the N2 component, and small values of the latencies of the P1-N1-P2 complex. Neirofiziologiya/Neurophysiology, Vol. 37, Nos. 5/6, pp. 452–458, September–December, 2005.     

Immature small ribosomal subunits can engage in translation initiation in Saccharomyces cerevisiae

It is generally assumed that, in Saccharomyces cerevisiae, immature 40S ribosomal subunits are not competent for translation initiation. Here, we show by different approaches that, in wild‐type conditions, a portion of pre‐40S particles (pre‐SSU) associate with translating ribosomal complexes. When cytoplasmic 20S pre‐rRNA processing is impaired, as in Rio1p‐ or Nob1p‐depleted cells, a large part of pre‐SSUs is associated with translating ribosomes complexes. Loading of pre‐40S particles onto mRNAs presumably uses the canonical pathway as translation‐initiation factors interact with 20S pre‐rRNA. However, translation initiation is not required for 40S ribosomal subunit maturation. We also provide evidence suggesting that cytoplasmic 20S pre‐rRNAs that associate with translating complexes are turned over by the no go decay (NGD) pathway, a process known to degrade mRNAs on which ribosomes are stalled. We propose that the cytoplasmic fate of 20S pre‐rRNA is determined by the balance between pre‐SSU processing kinetics and sensing of ribosome‐like particles loaded onto mRNAs by the NGD machinery, which acts as an ultimate ribosome quality check point.     

延缓go／no—go任务操作中猴尾核兴奋性氨基酸水平变化的微透析研究

本研究将脑内在体（ｉｎ ｖｉｖｏ）微透析采样技术和高效液相色谱－荧光检测分析法相结合,监测了猕猴在履行一种延缓ｇｏ／ｎｏ－ｇｏ任务中其尾核内的兴奋性氨基酸水平的变化。在这种行为任务操作中,猴必须根据记忆中保持的暗示信号的位置来发动（ｇｏ）或抑制（ｎｏ－ｇｏ）随后的运动反应,因此具有短时工作记忆性质。我们发现,在这种行为任务操作过程中,猴尾核透析液中的Ｇｌｕ和Ａｓｐ水平较操作前基础水平分别降低（３１     

Analysis of training-induced changes in ethyl acetate odor maps using a new computational tool to map the glomerular layer of the olfactory bulb

Odor quality is thought to be encoded by the activation of partially overlapping subsets of glomeruli in the olfactory bulb (odor maps). Mouse genetic studies have demonstrated that olfactory sensory neurons (OSNs) expressing a particular olfactory receptor target their axons to a few individual glomeruli in the bulb. While the specific targeting of OSN axons provides a molecular underpinning for the odor maps, much remains to be understood about the relationship between the functional and molecular maps. In this article, we ask the question whether intensive training of mice in a go/no-go operant conditioning odor discrimination task affects odor maps measured by determining c-fos up-regulation in periglomerular cells. Data analysis is performed using a newly developed suite of computational tools designed to systematically map functional and molecular features of glomeruli in the adult mouse olfactory bulb. This suite provides the necessary tools to process high-resolution digital images, map labeled glomeruli, visualize odor maps, and facilitate statistical analysis of patterns of identified glomeruli in the olfactory bulb. The software generates odor maps (density plots) based on glomerular activity, density, or area. We find that training up-regulates the number of glomeruli that become c-fos positive after stimulation with ethyl acetate.     

Surprising Effects of Synaptic Excitation

Typically, excitatory synaptic coupling is thought of as an influence that accelerates and propagates firing in neuronal networks. This paper reviews recent results explaining how, contrary to these expectations, the presence of excitatory synaptic coupling can drastically slow oscillations in a network and how localized, sustained activity can arise in a network with purely excitatory coupling, without sustained inputs. These two effects stem from interactions of excitatory coupling with two different forms of intrinsic neuronal dynamics, and both serve to highlight the fact that the influence of synaptic coupling in a network depends strongly on the intrinsic properties of cells in the network.This work was partially supported by the National Science Foundation, under award DMS-0414023     

狭果葶苈高温响应表达序列标签的分离与初步分析

目的:分离与分析白马雪山流石滩地区植物狭果葶苈高温响应基因,研究高山植物高温耐受机制。方法:应用磁珠介导的抑制消减杂交分离差异表达序列标签(EST),通过测序与Blastx比对,用Blast2go程序进行功能注释和代谢路径分析。结果:大部分EST功能与物质能量代谢、生物合成、蛋白和脂肪结合、转移酶活性相关,还有一些胁迫响应的基因。结论:狭果葶苈高温胁迫应答机制是非常复杂的,需要众多基因的参与。     

Preparative synthesis of dTDP-L-rhamnose through combined enzymatic pathways

dTDP-L-rhamnose, an important precursor of O-antigen, was prepared on a large scale from dTMP by executing an one-pot reaction in which six enzymes are involved. Two enzymes, dTDP-4-keto-6-deoxy-D-glucose 3,5-epimerase and dTDP-4-keto-rhamnose reductase, responsible for the conversion of dTDP-4-keto-6-deoxy-D-glucose to dTDP-L-rhamnose, were isolated from their putative sequences in the genome of Mesorhizobium loti, functionally expressed in Escherichia coli, and their enzymatic activities were identified. The two enzymes were combined with an enzymatic process for dTDP-4-keto-6-deoxy-D-glucose involving TMP kinase, acetate kinase, dTDP-glucose synthase, and dTDP-glucose 4,6-dehydratase, which allowed us to achieve a preparative scale synthesis of dTDP-L-rhamnose using dTMP and glucose-1-phosphate as starting materials. About 82% yield of dTDP-L-rhamnose was obtained based on initial dTMP concentration at 20 mM dTMP, 1 mM ATP, 10 mM NADH, 60 mM acetyl phosphate, and 80 mM glucose-1-phosphate. From the reaction with 20 ml volume, approximately 180 mg of dTDP-L-rhamnose was obtained in an overall yield of 60% after two-step purification, that is, anion exchange chromatography and gel filtration for desalting. The purified product was identified by HPLC, ESI-MS, and NMR, showing about 95% purity.     

Induction and detoxification of maize 1,4-benzoxazin-3-ones by insect herbivores

In monocotyledonous plants, 1,4‐benzoxazin‐3‐ones, also referred to as benzoxazinoids or hydroxamic acids, are one of the most important chemical barriers against herbivores. However, knowledge about their behavior after attack, mode of action and potential detoxification by specialized insects remains limited. We chose an innovative analytical approach to understand the role of maize 1,4‐benzoxazin‐3‐ones in plant–insect interactions. By combining unbiased metabolomics screening and simultaneous measurements of living and digested plant tissue, we created a quantitative dynamic map of 1,4‐benzoxazin‐3‐ones at the plant–insect interface. Hypotheses derived from this map were tested by specifically developed in vitro assays using purified 1,4‐benzoxazin‐3‐ones and active extracts from mutant plants lacking 1,4‐benzoxazin‐3‐ones. Our data show that maize plants possess a two‐step defensive system that effectively fends off both the generalist Spodoptera littoralis and the specialist Spodoptera frugiperda. In the first step, upon insect attack, large quantities of 2‐β‐d ‐glucopyranosyloxy‐4,7‐dimethoxy‐1,4‐benzoxazin‐3‐one (HDMBOA‐Glc) are formed. In the second step, after tissue disruption by the herbivores, highly unstable 2‐hydroxy‐4,7‐dimethoxy‐1,4‐benzoxazin‐3‐one (HDMBOA) is released by plant‐derived β‐glucosidases. HDMBOA acts as a strong deterrent to both S. littoralis and S. frugiperda. Although constitutively produced 1,4‐benzoxazin‐3‐ones such as 2,4‐dihydroxy‐7‐methoxy‐1,4‐benzoxazin‐3‐one (DIMBOA) are detoxified via glycosylation by the insects, no conjugation of HDMBOA in the insect gut was found, which may explain why even the specialist S. frugiperda has not evolved immunity against this plant defense. Taken together, our results show the benefit of using a plant–insect interface approach to elucidate plant defensive processes and unravel a potent resistance mechanism in maize.     

Enantioselective synthesis of (S)-2-amino-4-phenylbutanoic acid by the hydantoinase method

Biosynthesis of (S)-(+)-2-amino-4-phenylbutanoic acid (1) was performed by nonenantioselective hydantoinase and L-N-carbamoylase using racemic 5-[2-phenylethyl]-imidazolidine-2,4-dione (rac-2) as a substrate. The compounds involved in this biocatalysis process could be simultaneously resolved by high-performance liquid chromatography using Chirobiotic T column with a mobile phase of EtOH/H(2)O = 10/90 at pH 4.2-4.5. To our knowledge, this is the first report of the successful production of 1 by the combination of recombinant hydantoinase and L-N-carbamoylase.     

Synthesis of D‐Altritol Nucleosides with a 3′‐O‐Tert‐Butyldimethylsilyl Protecting Group

Four D‐altritol nucleosides with a 3′‐O‐tert‐butyldimethylsilyl protecting group are synthesized (base moieties are adenine, guanine, thymine and 5‐methylcytosine). The nucleosides are obtained by ring opening reaction of 1,5:2,3‐dianhydro‐4,6‐O‐benzylidene‐D‐allitol. Optimal reaction circumstances (NaH, LiH, DBU, phase transfer, microwave irridation) for the introduction of the heterocycles are base‐specific. For the introduction of the 3′‐O‐silyl protecting group, long reaction times and several equivalents of tert‐butyldimethylsilyl chloride are needed.     

Claisen–Schmidt condensation: Synthesis of (1S,6R)/(1R,6S)‐2‐oxo‐N,4,6‐triarylcyclohex‐3‐enecarboxamide derivatives with different substituents in H2O/EtOH

A simple, green, and direct three‐component condensation of acetophenone, aromatic aldehydes with 3‐oxo‐N‐phenylbutanamide (acetoacetanilide) to generate some novel (1S,6R)/(1R,6S)‐2‐oxo‐N,4,6‐triarylcyclohex‐3‐enecarboxamide derivatives was carried out over K₂CO₃ (10 mol%) with high efficiency in water/ethanol as green solvent at room temperature. This protocol proceeded via Claisen–Schmidt condensation and Michael addition. The present methodology offers several advantages, such as short reaction time, high yield, more readily available and inexpensive materials, more environmentally friendly, no need for column chromatography, simple work‐up procedure, and the absence of volatile and hazardous organic solvents.     

One-pot enzymatic production of dTDP-4-keto-6-deoxy-D-glucose from dTMP and glucose-1-phosphate

An enzymatic production method for dTDP-4-keto-6-deoxy-D-glucose, a key intermediate of various deoxysugars in antibiotics, was developed starting from dTMP, acetyl phosphate, and glucose-1-phosphate. Four enzymes, i.e., TMP kinase, acetate kinase, dTDP-glucose synthase, and dTDP-D-glucose 4,6-dehydratase' were overexpressed using T7 promoter system in the E. coli BL21 strain, and the dTDP-4-keto-6-deoxy-D-glucose was synthesized by using the enzyme extracts in one-pot batch system. When 20 mM dTMP of initial concentration was used, Mg2+ ion, acetyl phosphate, and glucose-1-phosphate concentrations were optimized. About 95% conversion yield of dTDP-4-keto-6-deoxy-D-glucose was obtained based on initial dTMP concentration at 20 mM dTMP, 1 mM ATP, 60 mM acetyl phosphate, 80 mM glucose-1-phosphate, and 20 mM MgCl(2). The rate-limiting step in this multiple enzyme reaction system was the dTDP-glucose synthase reaction. Using the reaction scheme, about 1 gram of purified dTDP-4-keto-6-deoxy-D-glucose was obtained in an overall yield of 81% after two-step purification, i.e., anion exchange chromatography and gel filtration.     

Chiral separation of pheniramine-like 3-phenyl-3-heteroarylpropylamines by CE and HPLC methods

Analytical CE and HPLC methods were developed for the chiral separation of halogen-substituted 3-phenyl-3-(2-pyridyl)propylamines 1-4 (1: 3-(4-fluorophenyl) approximately, 2: 3-(3,4-difluorophenyl) approximately, 3: 3-(4-chlorophenyl) approximately, 4: 3-(3,4-dichlorophenyl) approximately ), 3-(4-fluorophenyl)-3-(2-thiazolyl)propylamine (5), and 3-(4-fluorophenyl)-3-(1-benzylimidazol-2-yl)propylamine (6), which are building blocks for the preparation of very potent arpromidine-type histamine H(2) receptor agonists. All amines were enantioseparated by CE with resolutions of at least 1.8 using alpha-, beta-, or gamma-cyclodextrin (CD) as chiral selectors. With heparin as buffer additive for CE the optical antipodes of 1-4 and 6 were separated with resolutions > or = 1.8. On RP-18 columns the separation of the (+)-(S)-acetylmandelic acid amides of racemic 2 (R = 0.9, alpha = 1.07) and the thioureas prepared by addition of 6 to 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl isothiocyanate (R = 2.0, alpha = 1.20) was successful, whereas the diastereomeric ureas prepared from 3 and (+)-(S)-1-(1-naphthyl)ethyl isocyanate could not be resolved. Separation of the diastereomeric isoindoles prepared from 1-5, o-phthaldialdehyde and 2,3,4,6-tetra-O-acetyl-1-thio-beta-D-glucopyranoside was achieved on a RP-18 phase (R > or = 0.4, a > or = 1.02). Direct separation of the enantiomers of 3 and 4 was achieved on a Cyclobond I column (R > or = 0.9, alpha > or = 1.07). alpha- and beta-CD were also useful as mobile phase additives for HPLC (3 and 4: RP-18 column, beta-CD, R > or = 0.4, alpha > or = 1.03; 3: RP-18 column, alpha-CD: R = 0.5, alpha = 1.04).     

Chemical constituents of Papulaspora immersa, an endophyte from Smallanthus sonchifolius (Asteraceae), and their cytotoxic activity

Papulaspora immersa H. H. Hotson was isolated from roots and leaves of Smallanthus sonchifolius (Poepp. and Endl. ) H. Rob. (Asteraceae), traditionally known as Yacon. The fungus was cultured in rice, and, from the AcOEt fraction, 14 compounds were isolated. Among them, (22E,24R)‐8,14‐epoxyergosta‐4,22‐diene‐3,6‐dione ( 4 ), 2,3‐epoxy‐1,2,3,4‐tetrahydronaphthalene‐c‐1,c‐4,8‐triol ( 10 ), and the chromone papulasporin ( 13 ) were new secondary metabolites. The spectral data of the known natural products were compared with the literature data, and their structures were established as the (24R)‐stigmast‐4‐en‐3‐one ( 1 ), 24‐methylenecycloartan‐3β‐ol ( 2 ), (22E,24R)‐ergosta‐4,6,8(14),22‐tetraen‐3‐one ( 3 ), (?)‐(3R,4R)‐4‐hydroxymellein ( 5 ), (?)‐(3R)‐5‐hydroxymellein ( 6 ), 6,8‐dihydroxy‐3‐methylisocoumarin ( 7 ), (?)‐(4S)‐4,8‐dihydroxy‐α‐tetralone ( 8 ), naphthalene‐1,8‐diol ( 9 ), 6,7,8‐trihydroxy‐3‐methylisocoumarin ( 11 ), 7‐hydroxy‐2,5‐dimethylchromone ( 12 ), and tyrosol ( 14 ). Compound 4 showed the highest cytotoxic activity against the human tumor cell lines MDA‐MB435 (melanoma), HCT‐8 (colon), SF295 (glioblastoma), and HL‐60 (promyelocytic leukemia), with IC₅₀ values of 3.3, 14.7, 5.0 and 1.6 μM , respectively. Strong synergistic effects were also observed with compound 5 and some of the isolated steroidal compounds.     

Female sex pheromone of a nettle caterpillar,Monema flavescens,in China

Monema flavescens Walker (Lepidoptera: Limacodidae) is a multivoltine, generalist moth whose larvae cause serious damage to many types of trees. Pheromone lures prepared according to a study of a Japanese population were found to be ineffective at attracting M. flavescens nettle caterpillars in China, and some studies have shown intraspecific geographical differences in the composition of sex pheromones. We therefore reexamined the sex pheromone composition of M. flavescens in a Chinese population. In this study, the electroantennographically (EAG) active compounds in an extract from Chinese virgin females of M. flavescens were identified as (E)‐8‐decen‐1‐ol (E8‐10:OH), (Z)‐7,9‐decadien‐1‐ol (Z7,9‐10:OH), (Z)‐9,11‐dodecadien‐1‐ol (Z9,11‐12:OH), and (Z)‐9,11‐dodecadienal (Z9,11‐12:Ald) via coupled gas chromatographic‐electroantennographic detection (GC‐EAD) and coupled GC‐mass spectrometry (MS). Pheromone dimorphism might occur in this species, as this mixture of compounds in Chinese females was different from that of E8‐10:OH and E7,9‐10:OH extracted from Japanese females in previous research. In wind tunnel and field tests, the males were significantly attracted to a blend of the pheromone components E8‐10:OH, Z7,9‐10:OH, and Z9,11‐12:OH in a 100:5:4 ratio. The addition of Z9,11‐12:Ald did not change the male response. The optimized three‐component lure blend may provide a useful tool for monitoring and controlling Chinese populations of M. flavescens.