拟鹅观草属3种植物的核型研究

对禾本科小麦族拟鹅观草属物种Pseudoroegneria geniculata、P.geniculata ssp.scythica和P.geniculata ssp.pruinifera的核型进行了研究.结果显示:P.geniculata和P.geniculata ssp.scythica为四倍体物种,P.geniculata ssp.pruinifera为六倍体物种;P.geniculata、P.geniculata ssp.scythica和P.geniculata ssp.pruinifera的核型公式分别为2n=4x=28=18m(2sat)+10sm(2sat)、2n=4x=28=28m(2sat)和2n=6x=42=36m(6sat)+6sm(2sat);P.geniculata和P.geniculata ssp.pruinifera为2A核型,而P.geniculata ssp.scythica为1A核型.研究表明:3种植物的核型存在差异;P.geniculata ssp.pruinifera的核型为首次报道,其核型明显不同于P.geniculata和P.geniculata ssp.scythica.     

Revision of the Thalia geniculata complex (Marantaceae)

Within the Thalia geniculata complex, which corresponds to subgen. Arthrothalia Schum., three species have been recognized in recent taxonomic literature, viz. T. geniculata L., T. trichocalyx Gagnepain, and T. welwitschii Ridley. The variation pattern within this complex has been analyzed with the aid of pictorialized scatter diagrams and it is concluded that the entire complex is made up of a single polymorphic species, of which no further subdivision is justified. T. geniculata is redescribed and full synonymy is given.     

Characterization of chromosome-specific S-SAP markers and their use in studying genetic diversity in Aegilops species.

The short interspersed nuclear element (SINE), Au, was used to develop sequence-specific amplified polymorphism (S-SAP) markers for U- and M-genome chromosomes. The markers were localized using Triticum aestivum (wheat)-- Aegilops geniculata and wheat-- Aegilops biuncialis disomic chromosome addition lines. Thirty-seven markers distributed over 6 U and 6 M chromosomes were produced. A genetic diversity study carried out on 37 accessions from Ae. biuncialis, Ae. comosa, Ae. geniculata, and Ae. umbellulata suggested that Ae. biuncialis have arisen from its diploid ancestors more recently than Ae. geniculata. Several earlier studies indicated that the M genomes in polyploid Aegilops species had accumulated substantial rearrangements, whereas the U genomes remained essentially unmodified. However, this cannot be attributed to the preferential insertion of retroelements into the M genome chromosomes. Fourteen markers from a total of 8 chromosomes were sequenced; 3 markers were similar to known plant genes, 1 was derived from a long terminal repeat (LTR) retrotransposon, and 10 markers did not match to any known DNA sequences, suggesting that they were located in the highly variable intergenic regions.     

废烟叶提取液源尼古丁降解菌分离鉴定和特性

【目的】目前造纸法再造烟叶工艺已经成为我国重要的废烟叶处理和利用方式,该工艺中尼古丁的调控是很重要的待解决问题。从废烟叶提取液(Tobacco waste extract,TWE)中筛选高耐受高活性降解尼古丁微生物用来直接处理烟梗或烟末提取液中的尼古丁,可实现对尼古丁指标的调控。【方法】以尼古丁为唯一碳氮源的基本培养基为筛选平板,从废烟叶提取液中筛选降解尼古丁菌株;对分离获得的菌株进行形态、生理生化和16S r RNA基因序列分析比对,鉴定其种属;获得的菌株分别在基本培养基和废烟叶提取液中考察其生长和尼古丁降解效果。【结果】从废烟叶提取液中获得了一株尼古丁降解活性和耐受力较好的降解菌株Pseudomonas sp.JY-Q,且在TWE中也有较强的降解能力。【结论】Pseudomonas sp.JY-Q可用于水体和TWE环境尼古丁的降解,但共存的葡萄糖对其有抑制作用,有待深入研究。     

Obelin from the bioluminescent marine hydroid Obelia geniculata: cloning, expression, and comparison of some properties with those of other Ca2+-regulated photoproteins

A cDNA encoding the Ca2+-regulated photoprotein of the bioluminescent marine hydroid Obelia geniculata was cloned and sequenced. The cDNA is a 774 bp fragment containing two overlapping open reading frames, one of which contained 585 bp encoding a 195 amino acid polypeptide which obviously has the primary structure of the apoprotein of a calcium-regulated photoprotein. Many of the residues are identical to those in other Ca2+-regulated photoproteins: 86% compared with that from Obelia longissima, 76% with that from Clytia (Phialidium), 64% with that from Aequorea, and 64% with that from Mitrocoma(Halistaura). The obelin from O. geniculata was overexpressed in Escherichia coli, refolded from inclusion bodies, and purified. The yield of highly purified recombinant protein was 55-80 mg/L of LB medium. O. geniculata obelin has absorption maxima at 280 and 460 nm and a shoulder at approximately 310 nm. The calcium-discharged protein loses visible absorption but exhibits a new absorption maximum at 343 nm. The bioluminescence of the obelin from O. geniculata is blue (lambda(max) = 495 nm). In contrast, the fluorescence of the calcium-discharged protein is yellow-green (lambda(max) = 520 nm; excitation at 340 nm). This is in sharp contrast to aequorin in which the bioluminescence and fluorescence emission spectra of the calcium-discharged protein are almost identical (lambda(max) = 465 nm). The Ca2+ concentration-effect curve for O. geniculata obelin is similar to those of many other photoproteins: at [Ca2+] below approximately 10(-8) M, calcium-independent luminescence is observed, and at [Ca2+] approximately 10(-3) M, the luminescence reaches a maximum. Between these extremes, the curve spans a vertical range of almost 8 log units with a maximum slope on a log-log plot of about 2.5. In the absence of Mg2+ the rate constant for the rise of bioluminescence determined by the stopped-flow technique is about 450 s(-1). The effects of Mg2+ on the kinetics of bioluminescence are complicated, but at all concentrations studied they are relatively small compared to the corresponding effects on aequorin luminescence. At least with respect to speed and sensitivity to Mg2+, the obelins from both O. longissima and O. geniculata would appear to be more suitable than aequorin for use as intracellular Ca2+ indicators.     

Contributions to the cytòtaxonomy of the Commelinaceae

Representatives of the Tradescantia geniculata alliance (genus Gibasis Rafin.) in cultivation at Kew display considerable cytological and morphological diversity. Chromosome complements consist of either large or small chromosomeS. Plants with small chromosomes have either 2 n = 16 or 2 n = 32, and all form only bivalents at meiosis and have presumed basic numbers of x – 8 and x = 8 or 16 respectively. The 2 n = 32 accessions are considered to represent T.geniculata in its strict sense; the identity of the 2 n =16 plant is uncertain. Plants with large chromosomes have either 2 n = 16 or 2n = 20 and each forms quadrivalents to the extent that they can be considered as cytological autotetraploidS. Basic numbers are then x = 4 and x =5, the lowest yet recorded for the Commelinaceae. The identity of the x = 4 species is uncertain. The x = 5 plants are readily identified as T.karwinskyana.     

Molecular Mechanism of Nicotine Degradation by a Newly Isolated Strain,Ochrobactrum sp. Strain SJY1

A newly isolated strain, SJY1, identified as Ochrobactrum sp., utilizes nicotine as a sole source of carbon, nitrogen, and energy. Strain SJY1 could efficiently degrade nicotine via a variant of the pyridine and pyrrolidine pathways (the VPP pathway), which highlights bacterial metabolic diversity in relation to nicotine degradation. A 97-kbp DNA fragment containing six nicotine degradation-related genes was obtained by gap closing from the genome sequence of strain SJY1. Three genes, designated vppB, vppD, and vppE, in the VPP pathway were cloned and heterologously expressed, and the related proteins were characterized. The vppB gene encodes a flavin-containing amine oxidase converting 6-hydroxynicotine to 6-hydroxy-N-methylmyosmine. Although VppB specifically catalyzes the dehydrogenation of 6-hydroxynicotine rather than nicotine, it shares higher amino acid sequence identity with nicotine oxidase (38%) from the pyrrolidine pathway than with its isoenzyme (6-hydroxy-l-nicotine oxidase, 24%) from the pyridine pathway. The vppD gene encodes an NADH-dependent flavin-containing monooxygenase, which catalyzes the hydroxylation of 6-hydroxy-3-succinoylpyridine to 2,5-dihydroxypyridine. VppD shows 62% amino acid sequence identity with the hydroxylase (HspB) from Pseudomonas putida strain S16, whereas the specific activity of VppD is ∼10-fold higher than that of HspB. VppE is responsible for the transformation of 2,5-dihydroxypyridine. Sequence alignment and phylogenetic analysis suggested that the VPP pathway, which evolved independently from nicotinic acid degradation, might have a closer relationship with the pyrrolidine pathway. The proteins and functional pathway identified here provide a sound basis for future studies aimed at a better understanding of molecular principles of nicotine degradation.     

Copper Toxicity Tolerance in Aegilops and Haynaldia Seedlings

The seedling response to high Cu concentrations (1 and 10 μM CuSO₄ . 5 H₂O) was studied in Aegilops triuncialis, Ae. geniculata, Ae. cylindrica and Haynaldia villosa. The negative effect of Cu on the root growth was recorded at both concentrations, while the shoot growth was inhibited at 10 μM. The most tolerant was Ae. triuncialis, followed by Ae. geniculata. Ae. cylindrica and H. villosa were more sensitive. This revised version was published online in July 2006 with corrections to the Cover Date.     

Nicotine degradation enhancement by <Emphasis Type="Italic">Pseudomonas stutzeri</Emphasis> ZCJ during aging process of tobacco leaves

Nicotine is a key harmful component of tobacco and cigarettes, and the development of low-nicotine cigarettes is of increasing importance in the market. The objectives of this study are to isolate native nicotine-degrading strains and evaluate their feasibility for nicotine reduction during the aging (or fermentation) of tobacco leaves. A novel nicotine-degrading strain was isolated and identified as Pseudomonas stutzeri ZCJ based on its 16S rDNA sequence and morphological-biochemical characteristics. In submerged cultures, P. stutzeri ZCJ could tolerate 4.5 g/L nicotine and completely degrade 1.5 g/L nicotine within 24 h at 37°C and pH 7.4. The addition of glucose (1 g/L) could improve nicotine degradation by P. stutzeri ZCJ in submerged cultures. After submerged culturing, the cell suspension of P. stutzeri ZCJ could be utilized to improve nicotine reduction in tobacco leaves during solid-state fermentation. The nicotine content of tobacco leaves decreased by as much as 32.24% after 7 days of solid-state fermentation by P. stutzeri ZCJ, suggesting the industrial application potential of the native strain to enhance nicotine degradation during the aging of tobacco leaves.     

Conjugate of bovine serum albumin with nicotine

The preparation and characterization of a nicotine-albumin conjugate are reported. The nicotine derivative, 6-(p-aminobenzamido)nicotine, which was coupled to bovine serum albumin(BSA), was synthesized by the following sequence; $\text{1}$-nicotine→6-aminonicotine→6-(p-nitrobenzamido)nicotine→6-(p-aminobenzamido)nicotine. Thirty molecules of conjugated nicotine per molecule of BSA were distinguished by the determination of 6-aminonicotine after hydrolysis. The distribution of the conjugated nicotine on BSA was examined by the stoichiometry of the composed amino acids before and after conjugation, and also by the electrophoretic behavior of the conjugated BSA on a polyacrylamide gel.     

Microbiology and biochemistry of nicotine degradation

Several bacterial species are adapted to nicotine, the main alkaloid produced by the tobacco plant, as growth substrate. A general outline of nicotine catabolism by these bacteria is presented, followed by an emphasis on new insights based on molecular biology and biochemical work obtained with the catabolic plasmid pAO1 of Arthrobacter nicotinovorans. Its 165-kb sequence revealed the genetic structure of nicotine catabolism and allowed the assignment of new enzyme activities to specific gene products, which extends the known biochemical steps of this pathway. Potential implications of the progress in our understanding of bacterial breakdown of nicotine for biotechnological applications are discussed.     

A revised key to larvae of the genus Plectrocnemia (Polycentropodidae: Trichoptera) in Britain, with notes on Plectrocnemia brevis McLachlan

SUMMARY. The key distinguishes the previously unknown larva of Plectrocnemia brevis McLachlan from larvae of the other two British Plectrocnemia species, P. conspersa (Curtis) and P. geniculata McLachlan. Notes are given on the larval habitat, life cycle and identification of the adult of P. brevis.     

Pharmacokinetics of nicotine in adult and infant mice

Experiments were done to compare the time-courses of the nicotine concentration in the blood, heart, and brain of infant and adult mice after small and large single doses of radioactive nicotine tartrate. In some experiments the nicotine receptors were blocked with mecamylamine or hexamethonium, and their effects on nicotine levels were measured. The nicotine-induced tremor was allowed visually, and its effects on the heart rate were measured by ECG. In adult mice the peak levels of brain nicotine occurred at 10 min, whereas in infant mice the brain nicotine levels were still rising at 20 min. In the latter the blood and heart nicotine levels were higher than the respective brain levels, and the nicotine level in the brain stem exceeded the hemisphere level. The results were reversed in adult mice. A remarkable accumulation of nicotine in the infant heart was measured. Pretreatment with mecamylamine lowered brain nicotine levels in adult mice, and in infant mice the nicotine levels in blood and heart were lowered as well. This pretreatment abolished the nicotine tremor and its effects on the heart rate similarly in both age groups. This suggests that the difference in nicotine levels after mecamylamine in infant and adult mice may not depend solely on possible differences in circulatory changes but can represent differences in "receptor population" as well. Hexamethonium did not abolish the central depressant effect of nicotine on the heart rate nor did it lower the brain nicotine levels. This supports the view that there is some correlation of the central effects of nicotine and its brain levels.     

尼古丁降解菌SCUEC1菌株的分离及其降解基因

【目的】分离并鉴定1株具有尼古丁降解能力的细菌,研究其尼古丁降解特性并对其降解基因进行分析,为尼古丁微生物降解提供基础。【方法】从烟草种植地土壤中分离1株具有尼古丁降解能力的细菌,通过16S r RNA基因和生理生化特性对该菌株进行鉴定,检测该菌株尼古丁降解率与生长量的关系,并进一步对该菌株进行尼古丁浓度耐受性测定,采用高通量测序技术对菌株进行全基因组测序,BLAST比对分析尼古丁降解相关基因。【结果】筛选到1株具有尼古丁降解能力的细菌,经鉴定命名为根癌土壤杆菌(Agrobacterium tumerficience)SCUEC1菌株,根癌土壤杆菌SCUEC1菌株尼古丁降解率可达到94.81%,该菌株在尼古丁浓度为0.50–5.00 g/L范围内生长良好且有较高的尼古丁降解能力。对根癌土壤杆菌SCUEC1菌株全基因组序列进行BLAST比对分析,推测该菌株的尼古丁降解代谢途径与中间苍白杆菌SYJ1菌株的尼古丁降解途径相似。【结论】本研究揭示了Agrobacterium tumerficienceSCUEC1菌株具备尼古丁降解特性,初步推测出尼古丁降解相关基因和降解代谢途径,为尼古丁微生物降解提供基础。     

Isoenzymes and Taxonomy in Scandinavian Hydroids (Cnidaria, Campanulariidae)

Acid phosphatases, esterases and leucine aminopeptidases were studied in Campanularia integra, Clytia hemisphaerica (the johnstoni form), Laomedea ftexuosa, Gonothyraea loveni, Obelia geniculata, O. longissima and O. dichotoma , using polyacrylamide gel electrophoresis. Species-specific patterns were obtained, notably regarding acid phosphatase, despite strong individual variation. The electrophoretic results combined with differences in morphology and cnidom indicate that O. longissima and O. dichotoma are separate species. The acid phosphatase patterns of the two species and of O. geniculata showed basic similarities, supporting their assignment to a common genus. The profound differences in the acid phosphatase patterns of C. integra and L. flexuosa , may in conjunction with morphological distinction justify their assignment to separate genera. C. integra also included specimens of caliculata morphology: however, these did not deviate in their band patterns. Electrophoretograms of the typical O. dichotoma resembled those of the dubia and plicata forms. Moreover, O. gelatinosa with free Obelia medusae (sensu Hincks 1868) is suggested to be conspecific with O. longissima . The present study indicates that electrophoretic analyses, particularly of acid phosphatases presenting highly reproducible patterns, is a valuable complement to morphological characters when studying the taxonomy in hydroids.     

Chromosome isolation by flow sorting in Aegilops umbellulata and Ae. comosa and their allotetraploid hybrids Ae. biuncialis and Ae. geniculata

This study evaluates the potential of flow cytometry for chromosome sorting in two wild diploid wheats Aegilops umbellulata and Ae. comosa and their natural allotetraploid hybrids Ae. biuncialis and Ae. geniculata. Flow karyotypes obtained after the analysis of DAPI-stained chromosomes were characterized and content of chromosome peaks was determined. Peaks of chromosome 1U could be discriminated in flow karyotypes of Ae. umbellulata and Ae. biuncialis and the chromosome could be sorted with purities exceeding 95%. The remaining chromosomes formed composite peaks and could be sorted in groups of two to four. Twenty four wheat SSR markers were tested for their position on chromosomes of Ae. umbellulata and Ae. comosa using PCR on DNA amplified from flow-sorted chromosomes and genomic DNA of wheat-Ae. geniculata addition lines, respectively. Six SSR markers were located on particular Aegilops chromosomes using sorted chromosomes, thus confirming the usefulness of this approach for physical mapping. The SSR markers are suitable for marker assisted selection of wheat-Aegilops introgression lines. The results obtained in this work provide new opportunities for dissecting genomes of wild relatives of wheat with the aim to assist in alien gene transfer and discovery of novel genes for wheat improvement.     

Presence of 3-O-methyl-l-xylose in the lipopolysaccharide of Pseudomonas maltophilia N.C.T.C. 10257.

3-O-Methyl-L-xylose was isolated from whole cells of Pseudomonas maltophilia N.C.T.C. 10257. The sugar is a component of lipopolysaccharide from which a polysaccharide also containing L-rhamnose and L-xylose was released by mild acid hydrolysis. 3-O-Methyl-L-xylose was absent from five other strains of Ps. maltophilia and one strain of Pseudomonas geniculata.     

烟碱降解细菌的分离、鉴定及其降解性能的初步研究

从福建三明地区的土壤中分离得到一株能够高效降解烟碱的菌株 ,编号为DN2。该菌经常规的形态、生理生化分析以及 16SrDNA序列同源性分析 ,鉴定为Ochrobactrumintermedium ,属于α_变形杆细菌纲。该菌在 30℃～4 0℃和pH 6 . 0～ 9. 0范围内具有较高的降解活性 ,其最适值分别为 30℃和 6 5 ,烟碱的耐受浓度在无机盐培养基中可达到 4 0 0 0mg L。该菌能够以烟碱为唯一碳源生长 ,对于 5 0 0mg L烟碱的降解速率为 15mg L·h ,36h烟碱降解率为97. 6 5 %。该菌在烟草工业和环境保护上可能具有应用前景。     

Genome analysis of Elytrigia caespitosa, Lophopyrum nodosum, Pseudoroegneria geniculata ssp. scythica, and Thinopyrum intermedium (Triticeae: Gramineae).

To elucidate the genome constitutions of the tetraploid (2n = 4x = 28) species Elytrigia caespitosa, Lophopyrum nodosum, and Pseudoroegneria geniculata ssp. scythica and the hexaploid (2n = 6x = 42) Thinopyrum intermedium, meiotic pairing was studied in these species as well as 10 hybrids. Karyotype analysis with aceto-orcein stained root-tip cells was performed for the four species and the hybrids of T. bessarabicum with E. caespitosa, P. geniculata ssp. scythica, and T. intermedium. Karyotype analysis by Giemsa C-banding was carried out with the three tetraploid species and the two triploid hybrids involving T. bessarabicum. The species behaved as strict allopolyploids. All hybrids were male sterile with few stainable pollen grains. It is concluded from the results that the three tetraploid species have the genome formula JeJeSS and T. intermedium has the formula JeJeJeJeSS. The chromosomes of the Je and S genomes in these species had C-banding patterns differing from each other and from those of the extant diploid species. Based on these findings, the four species investigated should be placed in the same genus or the same section of a genus. However, new combinations are not proposed at this time pending future taxonomic investigation of the genome constitution of Elytrigia repens (L.) Nevski.