Detection of DNA methylation changes during seed germination in rapeseed （Brassica napus）

DNA methylation is a common yet important modi- fication of DNA in eukaryotic organisms. DNA methy- lation, especially methylation of cytosine (m5C), have both epigenetic and mutagenic effects on various cellu- lar activities such as differential gene exp…     

Patterns of DNA cytosine methylation between haploids and corresponding diploids in rice

In higher plant, about 30% cytosines are methy-lated[1], among which about 90% methylated sites lie in CpG dinucleotide and CpNpG trinucleotide[2]. The me-thylated DNA has inducing and epigenetic effects on cell biological procedures such as gene differen…     

Construct 2D nanostructure of co-adsorbed dipyridyl derivative by stabilization of hydrogen bond and long alkyl chains

The self-assembled structures of 4, 4‘‘-dionoyl-2,2‘‘-dipyridyl and its co-adsorption with stearic acid on highly oriented pyrolytic graphite (HOPG) have been studied by the scanning tunneling microscopy (STM). As a result, 4,4‘‘-dionoyl-2,2‘‘-dipyridyl forms a planar trans conformation in two cases, and through the co-adsorption with stearic acid, 4,4‘‘-dionoyl-2,2‘‘-dipyridyl and stearic acid form a well-ordered nanostructure.     

Enhanced hydrosen production by insertional inactivation of adhE gene in Klebsiella oxytoca HP1

Ethanol is the main byproduct of anaerobic H2-producing fermentation in Klebsiella oxytoca HP1. Two moles of NAD（P）H are consumed to yield one mole of ethanol that may decrease bacterial hydrogen production. In this article the adhE gene that codes for acetaldehyde dehydrogenase was disrupted for the first time. A homologous recombination vector pTA-Str was constructed in which the adhE gene was disrupted by inserting an aminoglycoside-3＇-adenyltransferase （aadA） gene. As expected, the vector includes the insertion 5＇-adhE-aadA-adhE-3＇. The amplified DNA fragment 5＇-adhE-aadA-adhE-3＇ from pTA-Str was transformed into K. oxytoca HP1 and one recombinant was obtained. PCR analysis of the resulting genomic DNA indicated the appropriate deletion and insertion. Compared with the H2-production of wild type K. oxytoca HP1, the hydrogen yield of the mutant increased by 16.07% and ethanol concentration decreased by 77.47%, suggesting that inactivation of the adhE gene in K. oxytoca HP1 is a potential method for enhancing bacterial H2-production.     

Genetic structure and diversity of Oryza sativa L. in Guizhou, China

Preserving many kinds of rice resources and rich variations, Guizhou Province is one of the districts with the highest genetic diversity of cultivated rice （Oryza sativa L.） in China. In the current research, genetic diversity and structure of 537 accessions of cultivated rice from Guizhou were studied using 36 microsetellite markers and 39 phenotypic characters. The results showed that the model-based genetic structure was the same as genetic-distance-based one using SSRs but somewhat different from the documented classification （mainly based on phenotype） of two subspecies. The accessions being classified into indica by phenotype but japonica by genetic structure were much more than that being classified into japonica by phenotype but indica by genetic structure. Like Ding Ying＇s taxonomic system of cultivated rice, the subspecific differentiation was the most distinct differentiation within cultivated rice. But the differentiation within indica or japonica population was different： japonica presented clearer differentiation between soil-watery ecotypes than indica, and indica presented clearer differentiation between seasonal ecotypes than japonica. Cultivated rices in Guizhou revealed high genetic diversity at both DNA and phenotypic levels. Possessing the highest genetic diversity and all the necessary conditions as a center of genetic diversity, region Southwestern of Guizhou was suggested as the center of genetic diversity of O. sativa L. from Guizhou.     

Synthesis of calix[4]dithiacrown platinum complexes and their catalytic behavior in the hydrosilylation of olefins with triethoxysilane

5,11,17,23-Tetrakis-1′, 1′-dimethylethyl-25,27-dihydroxy-26,28-1″, 7″, 13″-trioxa-4″, 10″-dithiatridecylcene-calix[4]arene (calix[4]dithiacrown-5) and its O-methylated derivate (dimethylcalix[4]dithiacrown-5) were synthesized fromp-tert-butylcalix[4] arene via 1, 3-lower rim functionalization with chloroethyltosylate, followed by ring-closing condensation with β,β/t'-dimercaptoethyl ether in the presence of sodium ethoxide as a base in reflux ethanol under nitrogen atmosphere, followed by methylation with methyltosylate in the presence of NaH as a base in dioxane. It was found that they can coordinate with platinous chloride and the platinous complexes are efficient catalysts for the hydrosilylation of olefins with triethoxysilane. Foundation item: Supported by National Natural Science Foundation of China Biography: CHEN Yuan-yin (1936-), male, Professor.     

Complete nucleotide sequence and genomic organization of Periplaneta fuliginosa densonucleosis virus

We have cloned the replicative form of thePeriplaneta fuliginosa densonucleosis virus (PfDNV) genome and determined its complete sequence. The sequence has 5 454 nucleotides (nt), the genome consists of an internal unique sequence flanked by inverted terminal repeats (201 nt). The first 122 nt at the 5′ end and the terminal 122 nt at the 3′ end of both plus and minus strands can fold into a typical hairpin structure. The genome contains seven major open reading frames (ORFs). The plus strand has 4 ORFs occupying the 5′ half of the plus strand, whereas the others span the 5′ half of the minus strand. Two potential promoters were found at map units (m.u.) 3 and 97. Computer analysis of sequence homologies with other parvoviruses suggests that the plus strand ofPf DNV encodes very likely the nonstructural proteins and the minus strand probably encodes the structural proteins.     

Inhibition of bromophenols against PTP1B and anti-hyperglycemic effect of <Emphasis Type="Italic">Rhodomela confervoides</Emphasis> extract in diabetic rats

Protein tyrosine phosphatase 1B （PTPIB） plays an important role as a negative regulator In insulin signaling pathways. PTPIB is an effective target for the treatment of type 2 diabetes mellitus. Four bromophenol derivatives from red algae Rhodomela confervoides, 2,2＇,3,3＇-tetrabromo-4,4＇,5,5＇-tetrahydroxydiphenyl methane （1）, 3-bormo-4,5-bis（2,3-dibromo-4,5-dihydroxybenzyl） pyrocatechol （2）, bis（2,3-dibromo-4,5-dihydroxybenzyl） ether （3） and 2,2＇,3-tribromo-3＇,4,4＇,5-tetrahydroxy-6＇-ethyloxymethyldiphenylmethane （4） showed significant inhibitory activity against PTPIB （IC50 were 2.4, 1.7, 1.5 and 0.84 μmol/L, respectively） as potential therapeutical agents for the treatment of type 2 diabetes mellitus. The anti-hyperglycemic effects of the ethanol extracts from If. confervoides on streptozotocin-induced diabetes （STZ-diabetes） in male Wistsr rats fed with high fat diet were investigated. The STZ-diabetic rats treated with medium-dose and high-dose alga extracts showed remarkable reductions in fasting blood glucose （FBG） as compared with the STZ-diabetic control. The results indicate that the in vivo anti-hyperglycemic activity of the R. confervoides extracts can be partially attributed to the inhibitory actions against PTPIB of the bromophenol derivatives and that may be of clinical Importance in improving the management of type 2 diabetes mellitus.     

Z3, a novel antisense snoRNA fromSaccharomyces cerevisiae

Small nucleolar RNA (snoRNA) is one of the most important elements participating in eukaryotic ribosomal biogenesis. The present report describes the results of the identification of a novel snoRNA, Z3, from yeast S. cerevisiae. Z3 snoRNA is 106 nts in length. It contains box C, D elements and a 13 nt complementarity to 25S rRNA. This antisense segment, together with the downstream box D, guides a 2′-O-ribose methylation of cytidine acid at position 2956th in yeast 25 S rRNA. Z3 snoRNA, encoded by an independent transcribed gene on the chromosome  of yeast, possesses the same functional elements responsible for the rRNA methylation site as that of the intron-encoded U35 snoRNA of vertebrate.     

A convenient preparation of enantiopure 1,1′-bi-2-naphtholsvia an inclusion complexation in the solid state

Inclusion reaction of racemic 1,1′-bi-2-naphthol and (S)-proline was examined under the solid state and the solid-liquid conditions. The results indicated that a solid mixture of racemic 1,1′-bi-2-naphthol and (S)-proline in a 1∶1 molar ratio was kept at 50–80 °C for 3–4 h, followed by treatment with benzene to give an insoluble solid and a benzene solution, from which (S)-(−)- and (R)-(+)-1,1′-bi-2-naphthols of a modest level of optical purity were obtained. After “kinetic” crystallization, both essentially enantiopure isomers were provided in 15%–35% overall yields, respectively. Foundation item: Supported by the National Natural Science Foundation of China (29972033) and the Key Science Research Foundation of Hubei Province (891P1305) Biography: Shan Zi-xing (1945-), male, Professor, research direction: asymmetric synthesis.     

Hydrothermal plume anomalies along the Central Indian Ridge

Water column turbidity and temperature were investigated along the Central Indian Ridge （CIR） from 25°19＇S to 23°48＇S during a December 2005 cruise on board Chinese PJV DayangYihao. Measurements were made using NOAA＇s MAPR （Miniature Autonomous Plume Recorder） sensors during CTD casts, TV grabber operations, and tow-yo profiles, yielding the following results on hydrothermal plume anomalies： （1） Strong hydrothermal turbidity and temperature anomalies were recorded over the previously discovered Kairei （25°19.2＇S, 70°02.4＇E） and Edmond （23°52.7＇S, 69°35.8＇E） vent fields, with the plume anomalies concentrated at depths of 2150--2300 m and 2700--2900 m, respectively. The maximum height of the turbidity anomalies near the Kairei vent field recorded in December 2005 was slightly below 2100 m, which is consistent with the plume depth measured in June 2001, indicating that the Kairei plume may have maintained its buoyancy flux in the intervening 4.5 years. （2） The water column beneath the Kairei plume has background anomalies of about 0.005ANTU, whereas no such background turbidity anomalies were observed below the Edmond hydrothermal plume. （3） No visible turbidity anomalies were detected from 24°42＇S to 24°12＇S including the Knorr Seamount. Thus 24°12＇S marks the southern end of the hydrothermal plume. （4） Significant turbidity anomalies were observed at four individual sections from 24°12＇S to 23°56＇S at the depth of 2500--3000 m along the eastern rift valley wall. Whether the individual sections of anomalies are connected is still unknown due to the absence of data at the intervening gaps. If the four sections are connected with each other and are linked to the Edmond vent field farther to the north, the total along-axis length of the plume anomaly would be more than 37 km, implying a plume incidence value Ph of 0.38, greater than the predicted Ph of 0.21 --0.25 based on the spreading rate of the Central Indian Ridge.     

Orientational domains at room temperature in La0.33Ca0.67MnO3 perovskite

Orientational domains at room temperature in orthorhombic perovskite La_0.33Ca_0.67MnO₃ were studied by group-theory and observed systematically using transmission electron microscopy. There are six orientational variants (A, A′, B, B′, C andC′) in orthorhombic perovskite La_0.33Ca_0.67MnO₃. Their orthorhombicb _o directions are parallel to thea _p,b _p andc _p directions of the cubic prototypic perovskite, respectively. In each case there are two orientational variants (e.g.,A andA′) with theira _o andc _o axes interchanged. Among the possible 15 boundaries between these 6 variants there are only two types of domain boundaries: (1) m<100>boundariesC′/C, A′/A, andB′/B. (2) m<110>boundaryiesC′/A, C′/A′, C′/B, C′/B′, C/A, C/A′, C/B, C/B′, B′/A, B′/A′, B/A, andB/A′. Foundation item: Supported by the National Natural Science Foundation of China (19974031) and US DOE(DE-AC02-98CH10886) Biography: WANG Ren-hui (1937-), male, Professor.     

Pairing problem of generators in Kac-Moody algebras

The following result is proved: in any Kac Moody algebra g(A) , (ⅰ) given any non central element h in the Cartan subalgebra  , or (ⅱ) given any real root vector x β, β∈Δ re . There exists y∈g(A) such that the subalgebra generated by y and h or y and x β contains the derived algebra g′(A) of g(A) .     

In silico identification of silkworm selenoproteomes

Selenium (Se) is an essential trace element in vivo. Its biological function is mainly exerted through selenoproteins. Selenocysteine (Sec), the active site of selenoproteins, is incorporated into the protein at an in-frame TGA codon under the guidance of Sec insertion sequence (SECIS) element in the 3′-untranslated region (UTR) of the gene. In this work, a method was developed and a series of programs were edited by PERL language to in silico identify selenoproteomes from the genome of domesticated silkworm (Bombyx mori). Out of 18510 annotated genes, 6348 was terminated with TGA codons, 249 containing both in-frame TGAs and SECIS elements in the 3′-UTRs. Alignments of those selenoprotein candidates with their cysteine (Cys)-containing homologs revealed that 52 genes had TGA/Cys pairs and similar flanking regions around the in-frame TGAs. Restricted by the patterns of SECIS elements only 5 genes were screened out to fully meet the requirements for selenoproteins. Among them glutathione S-transferase (GST) has been reported as a microbial selenoprotein, the other four are novel selenoproteins annotated as CG6024, CG5195, ATP-binding cassette transporter subfamily A (ABCA), and nuclear VCP-like protein. Derived from the general properties of GST, ABCA and VCP, silkworm selenoproteins may play important roles in redox regulation, Se storage and transportation, as well as cell apoptosis.     

MSAP在水稻害虫白背飞虱中的应用研究

甲基化敏感的扩增多态性分析方法 (MSAP)是在扩增片段长度多态性技术基础上建立起来的主要用来检测样品基因组DNA甲基化情况的一种方法,特别适用于全基因组范围内检测CCGG位点的胞嘧啶甲基化情况,在高等动物和许多植物上已广泛应用,但尚未有在昆虫中应用该方法的报道。从DNA提取、酶切基因组DNA用量、酶切和接头连接时间、电泳图谱显影方法等方面对MSAP方法进行了改进,并在水稻重要害虫白背飞虱上得到成功应用。这为将来在其它昆虫中使用该方法研究基因组DNA甲基化情况提供了一定借鉴和指导价值。且通过比较白背飞虱雌雄性别间和长短翅型间的MSAP图谱,发现雌雄性别间和长短翅型间的基因组DNA甲基化式样都存在明显的差异,说明DNA甲基化可能参与了性别和翅型分化的调节。     

Effect of internal deletion of Myosin II on growth and development ofDictyostelium discoideum

Four deletion mutantDictyostelium myosin II heavy chain genes, MyΔ824-941 (Δ1/ 3S2), MyΔ934-1454 (ΔS2), MyΔ934-1194 (ΔS2-1) and MyΔ1 157–1454 (ΔS2-2), were transformed by standard electfoporation into mhcA-cells (T-null), a mutantDictyostelium cell devoid of endogenous myosin II heavy chain gene. The growth, development and formation of fruiting bodies of cells expressing those mutant myosin II s under suspension culture were investigated by comparison with the wild type cell. The results indicate that internal deletion of myosin II affeds the growth and development ofDictyastelium. Furthermore, the longer the length of deletion, the more serious the defect in phenotype.