Phyllocarida and the origin of the Malacostraca

Tentative homologies with Decapoda are proposed for grooves on the carapace of Echinocaris and Montecaris. Together with F.R. Schram's hoploid trend, reinforced by the discovery of a raptorial limb in Sairocaris, this may strengthen a phyllocarid origin for Eumalacostraca. Both these trends, however, may be parallelisms, and phylogenetic analysis is required. Pleopods are here proved to have been present in additional Archaeostraca, which improves their ancestral condition. E. Dahl's view of the phyllocarids as an evolutionary dead end is falsified from fossils, and the phyllocarids are supported as a stem group of the Malacostraca.     

Synthesis and molecular structure of the all-trans- and the trans-cis-isomers of dichlorodimethyltin complexes of phosphoric triamides

Four new phosphoramidates with formula 4-RC₆H₄C(O)NHP(O)(NH(CH(CH₃)₂)₂, R = H (1), OCH₃ (2), CH₃ (3), Cl (4) and their diorganotin(IV) complexes with formula SnCl₂(CH₃)₂(X)₂, X = 1 (5), 2 (6), 3 (7) and 4 (8) were synthesized and characterized by NMR, IR spectroscopy and elemental analysis. The spectroscopic properties of complexes were compared with those corresponding ligands. The molecular structures for 5, 5·CH₃CN, 6·CH₃CN, 7 and 8 were established by X-ray diffraction analysis and shown that the tin atoms have a distorted octahedral coordination with trans-methyl groups. Two different all-trans and cis-trans isomers were obtained by changing the crystallization solvent system. The existence of CH₃CN in molecular packing of trans-cis isomers might be a packing factor governing the orientation of the ligands. Due to the presence of several hydrogen bond donors and acceptors on compounds, extended hydrogen-bonded networks were observed. The structure of 2 was also determined and possesses two crystallographically independent molecules in asymmetric unit. On forming complex 6·CH₃CN, the ligand 2 shows shortening of CO and P-N bond distances and increasing of PO bond length. Pseudopolymorphism of diorganotins in 5 and 5·CH₃CN is reported for the first time.     

The effect of the rcation/ranion ratio on the structural and chemical properties of N-chloroarenesulfonamidates

A comparative structural study on sodium and potassium N-chloroarenesulfonamidates has been carried out using X-ray diffraction and IR spectroscopy as experimental techniques. As shown by crystallographic studies, the sodium ions tend to incorporate more water oxygen atoms in their coordination spheres than the potassium ions, while the potassium congeners prefer the interaction with sulfonamidate moieties. The marked dissimilarity between the compositions of the coordination spheres as well as the different tendency of the sodium and potassium salts to absorb moisture from the air have been attributed to the different sizes of the sodium and potassium ions. The opposite shifts of the ν_as(SO₂) and ν(SN) bands upon dehydration have been ascribed to an increased polarization of the sulfonyl group by the metal centers. Based on IR spectroscopic observations, a weakening of the N-Cl bonds is suspected in the water-free compounds, which may contribute to the known thermal instability of the dehydrated salts of N-chloroarenesulfonamides. Various sections of IR spectra as well as X-ray powder diffraction patterns have proved to be suitable to identify the water-free and hydrated samples.     

Complete nucleotide sequence of the influenza A/PR/8/34 virus NS gene and comparison with the NS genes of the A/Udorn/72 and A/FPV/Rostock/34 strains.

The nucleotide sequence of the NS gene of the human influenza virus A/PR/8/34 was determined and found to be the same length (890 nucleotides) as the NS gene of another human influenza virus A/Udorn/72 and of the avian isolate A/FPV/Rostock/34. Comparison of the sequences of the NS genes of the two human influenza viruses shows an 8.9% difference whereas the NS gene of the avian isolate differs by only 8% from that of the human strain A/PR/8/34. The extensive sequence similarity among these three genes does not support the notion of species specific homology groups among NS genes of avian and human influenza virus strains. The primary sequence of the A/PR/8/34 NS gene is consistent with the findings that the influenza virus NS gene may code for two overlapping polypeptides. In addition, an open reading frame potentially coding for a polypeptide 167 amino acids in length was found in the negative strand RNA of the A/PR/8/34 virus NS gene.     

Evidence that a mustard seedling responds to the amount of Pfr and not to the Pfr/Ptotratio

Abstract Phytochrome-mediated anthocyanin synthesis of the mustard seedling (Sinapis alba L.) was investigated. Light pre-treated and dark-grown seedlings differing in responsiveness and level of phytochrome (P_tot) were compared. The data obtained support the traditional view that a seedling measures the amount of P_fr. The alternative view that a plant measures the P_fr/P_tot ratio does not seem to be compatible with the data obtained with the mustard seedling.     

Distribution and Pharmacological Properties of the GABAA/ Benzodiazepine/Chloride Ionophore Receptor Complex in the Brain of the Fish Anguilla anguilla

In the present study, we characterized the distribution and the pharmacological properties of the different components of the GABAA receptor complex in the brain of the eel (Anguilla anguilla). Benzodiazepine recognition sites labeled "in vitro" with [3H]flunitrazepam ([3H]FNT) were present in highest concentration in the optic lobe and in lowest concentration in the medulla oblongata and spinal cord. A similar distribution was observed in the density of gamma-[3H]aminobutyric acid ([3H]GABA) binding sites. GABA increased the binding of [3H]FNT in a concentration-dependent manner, with a maximal enhancement of 45% above the control value, and, vice versa, diazepam stimulated the binding of [3H]GABA to eel brain membrane preparations. The density of benzodiazepine and GABA recognition sites and their reciprocal regulation were similar to those observed in the rat brain. In contrast, the binding of the specific ligand for the Cl- ionophore, t-[35S]butylbicyclophosphorothionate ([35S]TBPS), to eel brain membranes was lower than that found in the rat brain. In addition, [35S]TBPS binding in eel brain was less sensitive to the inhibitory effects of GABA and muscimol and much more sensitive to the stimulatory effect of bicuculline, when compared with [35S]TBPS binding in the rat brain. Moreover, the uptake of 36Cl- into eel brain membrane vesicles was only marginally stimulated by concentrations of GABA or muscimol that significantly enhanced the 36Cl- uptake into rat brain membrane vesicles. Finally, intravenous administration of the beta-carboline inverse agonist 6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylic acid methyl ester (20 mg/kg) and of the chloride channel blocker pentylenetetrazole (80 mg/kg) produced convulsions in eels that were antagonized by diazepam at doses five to 20 times higher than those required to produce similar effects in rats. The results may indicate a different functional activity of the GABA-coupled chloride ionophore in the fish brain as compared with the mammalian brain.     

Sequence analysis and functional characterization of the promoter of the PiceaglaucaCinnamylAlcoholDehydrogenase gene in transgenic white spruce plants

The enzyme Cinnamyl Alcohol Dehydrogenase (CAD) catalyses the last step of lignin monomer synthesis, and is considered as a molecular marker of cell wall lignification in different plants species. Here, we report the isolation and analysis of 5′ flanking genomic DNA regions upstream to the CAD gene, from two conifers, i.e. white spruce (Picea glauca (Moench) Voss) and loblolly pine (Pinus taeda L.). Sequence comparisons with available CAD gene promoters from angiosperms highlighted the conservation of cis-elements matching MYB, WRKY and bHLH binding sites. Functional characterization of the P. glauca CAD promoter used P. glauca seedlings stably transformed with a DNA fragment of 1,163 base pairs (PgCAD) fused to the β-glucuronidase (GUS) gene. Histochemical observations of different vegetative organs of the transgenic trees showed that this sequence was sufficient to drive GUS expression in lignifying tissues, and more specifically in differentiating xylem cells. Quantitative RT-PCR experiments also indicated that the native CAD gene was preferentially expressed in differentiating xylem both in stems and roots. In addition, GUS expression driven by the PgCAD promoter was wound-inducible which was consistent with the accumulation of CAD mRNA in response to jasmonate application and mechanical wounding. The spruce CAD promoter represents a valuable tool for research and biotechnology applications related to xylem and wood. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Effects of cadmium and lead on the accumulation of Ca2+ and K+ and on the influx and translocation of K+ in wheat of low and high K+ status

The effects of cadmium and lead on the internal concentrations of Ca²⁺ and K⁺, as well as on the uptake and translocation of K(⁸⁶Rb⁺) were studied in winter wheat (Triticum aestivum L. a. MV-8) grown hydroponically at 2 levels of K⁺ (100 uM and 10 mM). Cd²⁺ and Pb²⁺ were applied in the nutrient solution in the range of 0.3 to 1000 u.M. Growth was more severely inhibited by Cd²⁺ and in the high-K⁺ plants as compared to Pb^z+ and low-K⁺ plants. Ions of both heavy metals accumulated in the roots and shoots, but the K⁺ status influenced their levels. Ca²⁺ accumulation was increased by low concentrations of Cd²⁺ mainly in low-K⁺ shoots, whereas it was less influenced by Pb²⁺. The distribution of Cd²⁺ and Ca²⁺ in the plant and in the growth media indicated high selectivity for Cd²⁺ in the root uptake, while Ca²⁺ was preferred in the radial and/or xylem transport. Cd²⁺ strongly inhibited net K⁺ accumulation in high-K⁺ plants but caused stimulation at low K⁺ supply. In contrast, the metabolis-dependent influx of K⁺(⁸⁶Rb⁺) was inhibited in low-K⁺ plants, while the passive influx in high-K⁺ plants was stimulated. Translocation of K⁺ from the roots to the shoots was inhibited by Cd²⁺ but less influenced in Pb²⁺-treated plants. It is concluded that the effects of heavy metals depend upon the K⁺-status of the plants.     

Effect of error of the quasi-steady-state approximation on the estimation of Km and Vm from a single time curve

For an irreversible, one-substrate enzyme mechanism, post-transient time curves of the substrate and the product are approximately described by different equations of the steady-state type. The magnitude of error of these approximations is shown to be small either at low enzyme/substrate or at low enzyme/ Michaelis-constant ratios. The effect of error on the kinetic parameters estimated from a single time curve is evaluated. It is shown that a set of well-separated substrate con centrations (which are still high relative to the concentration of enzyme) is crucial for obtaining accurate estimates of the parameters.     

Functional interactions between the gene tetanic and the Shaker gene complex of Drosophila

Different phenotypes associated with the tetanic (tta) mutation such as appendage contraction, maternal effect and low viability and fertility are enhanced by one extra dose of the Shaker gene complex (ShC). The tta mutation is lethal with two extra doses of ShC. In addition, tta embryos have a defective nervous system. In this paper, I analyse the interaction between tta and ShC to gain insight into their relationship. Aneuploid analysis suggests that the lethality is due to an interaction of the tta mutation with the maternal effect (ME) region of this gene complex. Mutations in the ME region of ShC partially suppress this interaction. Trans-heterozygous combinations of MEI[l(1)305] and MEIII [l(1)459] mutations causes dominant lethality in a tta background. Trans-heterozygous combinations of an MEII [l(1)1359] mutation with the cited MEI and MEIII mutations are lethal in a tta background. Double mutant combinations and gene dosage experiments, suggest that tta also interacts with the viable (V) region of ShC. These specific genetic interactions indicate that tta and the ME and V regions of ShC are functionally related. These results, together with the previous electrophysiological, molecular and biochemical studies on these mutants suggest an interaction at the protein level. Thus, in the case of the V region, the tta gene product may modulate the activity of the K⁺ channels encoded in this region. Furthermore, the extreme dosage sensitivity of the interaction between tta and ShC suggests a stoichiometric requirement for the different gene products involved, which might be physically associated and form heteromultimers.     

Identification of the major constituents of Hypericum perforatum by LC/SPE/NMR and/or LC/MS

The newly established hyphenated instrumentation of LC/DAD/SPE/NMR and LC/UV/(ESI)MS techniques have been applied for separation and structure verification of the major known constituents present in Greek Hypericum perforatum extracts. The chromatographic separation was performed on a C18 column. Acetonitrile-water was used as a mobile phase. For the on-line NMR detection, the analytes eluted from column were trapped one by one onto separate SPE cartridges, and hereafter transported into the NMR flow-cell. LC/DAD/SPE/NMR and LC/UV/MS allowed the characterization of constituents of Greek H. perforatum, mainly naphtodianthrones (hypericin, pseudohypericin, protohypericin, protopseudohypericin), phloroglucinols (hyperforin, adhyperforin), flavonoids (quercetin, quercitrin, isoquercitrin, hyperoside, astilbin, miquelianin, I3,II8-biapigenin) and phenolic acids (chlorogenic acid, 3-O-coumaroylquinic acid). Two phloroglucinols (hyperfirin and adhyperfirin) were detected for the first time, which have been previously reported to be precursors in the biosynthesis of hyperforin and adhyperforin.     

Allelopathic effects of Ulva pertusa , Corallina pilulifera and Sargassum thunbergii on the growth of the dinoflagellates Heterosigma akashiwo and Alexandrium tamarense

The allelopathic effects of fresh tissue, dry powder and aqueous extracts of three macroalgae, Ulva pertusa, Corallina pilulifera and Sargassum thunbergii, on the growth of the dinoflagellates Heterosigma akashiwo and Alexandrium tamarense were evaluated using coexistence culture systems in which concentrations of the three macroalga were varied. The results of the coexistence assay showed that the growth of the two microalgae was strongly inhibited by using fresh tissue, dry powder and aqueous extracts of the three macroalga; the allelochemicals were lethal to H. akashiwo at relatively higher concentrations of the three macroalga. The macroalgae showing the most allelopathic effect on H. akashiwo and A. tamarense using fresh tissue were U. pertusa and S. thunbergii, using dry powder were S. thunbergii and U. pertusa, and using aqueous extracts were U. pertusa and C. pilulifera. We also examined the potential allelopathic effect on the two microalgae of culture filtrate of the three macroalga; culture medium filtrate initially exhibited no inhibitory effects when first added but inhibitory effects became apparent under semi-continuous addition, which suggested that continuous release of small quantities of rapidly degradable allelochemicals from the fresh macroalgal tissue were essential to effectively inhibit the growth of the two microalgae.     

Genetic analysis of the bchC and bchA genes of Rhodobacter sphaeroides

Summary This study has identified by sequence analysis a single gene in the bchC locus of Rhodobacter sphaeroides and three genes, designated bchX, Y and Z, in the bchA locus, which was previously thought to contain only a single gene. All four genes may reside within the same operon and are transcribed in the order bchC-X-Y-Z. Complementation analysis of eight transposon insertion mutants within these genes suggests that bchX, Y and Z are essential for the reduction of 2-devinyl-2hydroxyethyl chlorophyllide a and that bchC encodes the 2-desacetyl-2-hydroxyethyl bacteriochlorophyllide a dehydrogenase. Similarity between the putative BchX protein and dinitrogenase reductase proteins suggests that BchX may also be a reductase, supplying electrons for reduction of 2-devinyl-2-hydroxyethyl chlorophyllide a.     

Primary structure of the tms and prs genes of Bacillus subtilis

Summary The nucleotide sequence was determined of a 3211 nucleotide pair EcoRI-PvuII DNA fragment containing the tms and prs genes as well as a part of the ctc gene of Bacillus subtilis. The prs gene encodes phosphoribosylpyrophosphate (PRPP) synthetase, whereas the functioning of the tms and ctc gene products remains to be established. The prs gene contains an open reading frame of 317 codons resulting in a subunit M_r of 34828. An open reading frame comprising the tms gene contained 456 codons resulting in a putative translation product with an M_r of 49554. Comparison of the deduced B. subtilis PRPP synthetase amino acid sequence with PRPP synthetases from Escherichia coli and rat liver showed extensive similarity. The deduced Tms amino acid sequence was found to be 43% similar to the deduced amino acid sequence of ecourfl, a gene of E. coli with unknown function.     

瑞香属和荛花属的数量分类研究

瑞香属和荛花属为瑞香科瑞香亚科的落叶或常绿灌木,中国西南部是瑞香属和荛花属的重要分化中心。全世界共有瑞香属95种、荛花属70种,中国分布有瑞香属52种、荛花属49种。瑞香属和荛花属的分类学研究一直存在不同程度的分歧。花盘形状和果实类型在传统分类中一直是区分瑞香属和荛花属的典型特征,而花盘形态和果实类型在2个属中存在交叉和过渡,部分植物分类学家根据这些特征将两个属进行过不同程度的归并。该研究采用数量分类法对瑞香属77种(变种)和荛花属62种(变种)植物,选取32个形态学性状进行聚类分析和主成分分析。结果表明:聚类分析和主成分分析均显示两属均未形成单系类群。在主成分分析中,前3个主成分分析的贡献值为35.56%,传统分类中用来区分两属的花盘形状、叶序及果实类型等特征对前3个主成分贡献相对较小,因此,传统分类学中对这两个属进行区分的性状并没有典型的分类学意义。同时,聚类图和主成分分析得到的散点图均不能将这两个属区分开来。数量分类研究结果显示两属植物存在明显的交叉,支持瑞香属和荛花属不是两个独立自然类群的观点。     

Physical linkage of the SLG and SRK genes at the self-incompatibility locus of Brassica oleracea

Summary In Brassica oleracea, the pollen-stigma interaction of self-incompatibility is controlled by a single genetically defined locus designated S. Molecular studies have identified two genes that are tightly linked to the classically defined S locus: The S-Locus Glycoprotein (SLG) gene and the S-Receptor Kinase (SRK) gene. In previous RFLP linkage analyses with probes specific for SLG and SRK, we were unable to identify any recombination events between SLG, SRK, and self-incompatibility phenotype. In this paper, we use pulsed-field gel electrophoresis (PFGE) in conjunction with DNA blot analysis to characterize the S-locus region from two highly divergent self-incompatibility genotypes, S ₂ and S ₆. We establish the physical linkage of SLG and SRK in each genotype, and demonstrate that the two genes are separated by a maximum distance of 220 kb in the S ₆ genotype and 350 kb in the S ₂ genotype. Furthermore, a comparison of the data from the two genotypes reveals that a high level of polymorphism exists across the entire S-locus region.