Synthesis and Antiproliferative Activity of 2,5-bis(3′-Indolyl)pyrroles,Analogues of the Marine Alkaloid Nortopsentin

2,5-bis(3′-Indolyl)pyrroles, analogues of the marine alkaloid nortopsentin, were conveniently prepared through a three step procedure in good overall yields. Derivatives 1a and 1b exhibited concentration-dependent antitumor activity towards a panel of 42 human tumor cell lines with mean IC₅₀ values of 1.54 μM and 0.67 μM, respectively. Investigating human tumor xenografts in an ex-vivo clonogenic assay revealed selective antitumor activity, whereas sensitive tumor models were scattered among various tumor histotypes.     

Determination of the Chemical Structures of Tandyukisins B–D,Isolated from a Marine Sponge-Derived Fungus

Tandyukisins B–D (1–3), novel decalin derivatives, have been isolated from a strain of Trichoderma harzianum OUPS-111D-4 originally derived from the marine sponge Halichondria okadai, and their structures have been elucidated on the basis of spectroscopic analyses using 1D and 2D NMR techniques. In addition, their chemical structures were established by chemical transformation. They exhibited weak cytotoxicity, but selective growth inhibition on panel screening using 39 human cancer cell lines.     

Synthesis and application of o,o′-dihydroxyazo dyes and their metal complexes

This paper presents the synthesis of metal complex acid dyes obtained from the reaction of o,o′-dihydroxyazo dyes and chromium and cobalt sulfate. The ¹H-NMR, FT-IR and UV/Visible Spectrophotometer, TLC (Thin Layer Chromatography) and ICP (Ion Chromatography) of the intermediates and the metal complexes were studied and compared. Their properties such as dyeing, fastness and toxicity on nylon were also assessed according to standard methods.     

Antibacterial Activity of 2-(2′,4′-Dibromophenoxy)-4,6-dibromophenol from Dysidea granulosa

2-(2′,4′-Dibromophenoxy)-4,6-dibromophenol isolated from the marine sponge Dysidea granulosa (Bergquist) collected off the coast of Lakshadweep islands, Indian Ocean, exhibited potent and broad spectrum in-vitro antibacterial activity, especially against methicillin resistant Staphylococcus aureus (MRSA), methicillin sensitive Staphylococcus aureus (MSSA), vancomycin resistant Enterococci (VRE), vancomycin sensitive Enterococci (VSE) and Bacillus spp. Minimal inhibitory concentration (MIC) was evaluated against 57 clinical and standard strains of Gram positive and Gram negative bacteria. The observed MIC range was 0.117–2.5 μg/mL against all the Gram positive bacteria and 0.5–2 μg/mL against Gram negative bacteria. The in-vitro antibacterial activity observed was better than that of the standard antibiotic linezolid, a marketed anti-MRSA drug. The results establish 2-(2′,4′-dibromophenoxy)-4,6-dibromophenol, as a potential lead molecule for anti-MRSA and anti-VRE drug development.     

Synthesis and properties of symmetrically substituted 4,4′-bis(1,3,5-triazinyl)-diamino stilbene-2,2′-disulfonic acid derivatives as UV absorbing and fluorescent whitening agents

The fluorescence properties of textiles dyed with optical brighteners have been widely reported in literature. However, little sufficient study has investigated the UV protection properties of textiles dyed with fluorescent whitening agents (FWAs). This study reports the synthesis of a series of stilbene-triazine compounds and their performance on cotton fiber as UV absorbing and FWAs. Triazinyldiaminostilbene compounds were synthesized by reacting 4,4′-diaminostilbene-2,2′-disulfonic acid with 2,4,6-trichloro-1,3,5-triazine to give 4,4′-bis(4,6-dichloro-1,3,5-triazin-2-yl)aminostilbene-2,2′-disulphonic acid. This intermediate was further condensed in two steps with amines by nucleophilic substituents on their triazine moiety. The structure of synthesized compounds were characterized by spectroscopic techniques i.e. IR, UV, elemental analysis and conformed by proton NMR Spectroscopy. These compounds were applied to cotton fiber as fluorescent whitening and UV absorbing agents. Their performances were evaluated with regards to whitening effects, ultraviolet protection factor (UPF), degree of exhaustion and fastness test.     

海南龙血树类黄酮3′-羟化酶基因(DcF3′H)的克隆与表达分析

类黄酮3′-羟化酶(Flavonoid 3′-hydroxylase,F3′H)是植物黄酮类化合物骨架修饰途径中的关键酶之一,在形成结构多样化的黄酮类化合物中起重要作用。在前期已获得的龙血树转录组数据基础上克隆了1个海南龙血树F3′H基因,命名为DcF3′H。DcF3′H含有的开放阅读框长1 533 bp,编码510个氨基酸。推导的DcF3′H分子量为58 ku,等电点p I为6.59。DcF3′H含有细胞色素P450的保守结构域和CYP基序,与甘蔗、玉米、猕猴桃、小麦、烟草、黄瓜和大豆等植物的F3′H同源性分别为76%、75%、77%、74%、75%、76%和75%。进化树分析表明,DcF3′H与中国水仙亲缘关系较近,与苜蓿和鹰嘴豆的亲缘关系较远。荧光定量表达结果显示:DcF3′H在根、茎、叶、花和果等组织中均有表达,其中在花中表达量最高,根中表达量最低;无机盐诱导剂处理能显著提高DcF3'H的表达量,处理3 d时DcF3′H的表达量提高了5.58倍。此结果将为进一步研究海南龙血树类黄酮3′-羟化酶基因的功能奠定基础。     

Molecular weight and structure units of (1→3, 1→4)-β-glucans in dough and bread made from hull-less barley milling fractions

Milling fractions of hull-less barley, and dough and bread with hull-less barley flour (40%) and wheat flour (60%) were analysed in an investigation of how the properties of (1→3, 1→4)-β-glucan were affected by milling, dough formation and bread making. Calcofluor average molecular weight $({\overline{M}}_{\text{cf}})$ and molecular weight distribution and the cellotriosyl/cellotetraosyl ratio of the (1→3, 1→4)-β-glucan were determined. Four different hull-less barley samples were milled to produce straight-run white flours, shorts, bran and whole-meal flours. The molecular weight distributions were unimodal for all fractions, and the $({\overline{M}}_{\text{cf}})$ range was between 117×10⁴ and 188×10⁴. These parameters were similar for all barleys, although $({\overline{M}}_{\text{cf}})$ was somewhat lower in white flour and bran fractions and somewhat higher in shorts and whole-meal. The cellotriosyl/cellotetraosyl ratio (1.5–1.8) was also similar in all fractions. Doughs and breads were made to study how flour type (sifted or whole-meal barley flour), water content, yeast, mixing time and fermentation time affect (1→3, 1→4)-β-glucan. The molecular weight distribution of (1→3, 1→4)-β-glucan was polymodal with two or three populations for all doughs and breads, and the $({\overline{M}}_{\text{cf}})$ decreased with increasing mixing and fermentation time. These results indicated that (1→3, 1→4)-β-glucan was degraded by endogenous β-glucanases in the barley and/or wheat flour. The molecular weight was not significantly affected by bread-baking and other factors. After mixing and fermentation the cellotriosyl/cellotetraosyl ratio was about 1.7–1.8 and was thus not significantly different from that of the flour blends. Thus to retain high molecular weight (1→3, 1→4)-β-glucan, which is important for its cholesterol-lowering effect, it is thus important to keep the mixing and fermentation time as short as possible when baking hull-less barley bread.     

Interpreting redox potential (Eh) and diffusive fluxes of phosphorus (P) and nitrate (NO3−) from commercial rice grown on histosols

Paddy and Water Environment - In South Florida, approximately 11,000 ha of rice is grown every summer on highly organic histosols. With no added fertilizer inputs of phosphorus (P) or...     

Distribution of (1-3)(1-4)-β-d-glucans in kernels of selected cultivars of naked and hulled barley

The objective of this study was to determine the distribution of (1-3)(1-4)-β-d-glucans in the kernels of three high-glucan lines of naked barley (STH 4561, STH 4671 and STH 4676), a low-glucan line (STH 4572), and two low-glucan comparative cultivars (naked – Rastik, and hulled – Stratus). The content of (1-3)(1-4)-β-d-glucans assayed with the enzymatic method varied within the range from 4.04 to 5.71% dry matter basis. Microspectrophotometric analysis revealed significant differentiation in the structure of the kernels and in the distribution of (1-3)(1-4)-β-d-glucans; it also indicated a necessity of applying such processing methods as are appropriate to the distribution of functional components. The distribution of functional components in the high-glucan lines of naked barley makes them ideal for utilization both in the milling technology and in the production of grits and flakes.     

Butremycin,the 3-Hydroxyl Derivative of Ikarugamycin and a Protonated Aromatic Tautomer of 5′-Methylthioinosine from a Ghanaian Micromonospora sp. K310

A new actinomycete strain Micromonospora sp. K310 was isolated from Ghanaian mangrove river sediment. Spectroscopy-guided fractionation led to the isolation of two new compounds from the fermentation culture. One of the compounds is butremycin (2) which is the (3-hydroxyl) derivative of the known Streptomyces metabolite ikarugamycin (1) and the other compound is a protonated aromatic tautomer of 5′-methylthioinosine (MTI) (3). Both new compounds were characterized by 1D, 2D NMR and MS data. Butremycin (2) displayed weak antibacterial activity against Gram-positive S. aureus ATCC 25923, the Gram-negative E. coli ATCC 25922 and a panel of clinical isolates of methicillin-resistant S. aureus (MRSA) strains while 3 did not show any antibacterial activity against these microbes.     

Vitamin C and quercetin modulate DNA-damaging effect of N-methyl-N′-nitro-N-nitrosoguanidine (MNNG)

The effects of natural compounds, vitamin C and quercetin, present in fruitsand vegetables, on the DNA damaging activity of a food carcinogen N-methyl-N-nitro-N-nitrosoguanidine (MNNG) were examinedusing the comet assay. Vitamin C, at a concentration of 50 M,inhibited MNNG-induced DNA damage in human lymphocytes. Quercetin,up to a concentration of 10 M, increased the extent of DNA damage,but at concentrations above 10 M decreased damage below controlvalues. Furthermore, quercetin had a strong antioxidant activity againstoxidative damage evoked by H₂O₂ at 10 M. The resultsobtained suggest that vitamin C and quercetin may have anti- orpro-oxidative properties depending on the state of the cell.     

Determination of (1→3),(1→4)-β-D-Glucanase Activity by a Calcofluor-Flow Injection Analysis Method

A new methodology for the determination of (1→3),(1→4)-β-d-glucanase activity has been developed. The concentration decay curves corresponding to the depolymerisation of high molecular weight barley (1→3),(1→4)-β-d-glucan by pure (1→3),(1→4)-β-d-glucanase (E.C. 3.2.1.73) fromBacillus subtilisand by crude (1→3),(1→4)-β-d-glucanase from different malts were monitored by the Calcofluor-FIA method. In all cases, the high molecular weight (17Instituto de Agroquı́mica y Tecnologı́a de Alimentos (CSIC)rarr;3),(1→4)-β-d-glucan decay curves fitted very well to an empirical formula describing the change in substrate concentration with time. The curves possess an inflexion point at which the depolymerisation rate of the substrate reaches a maximum. This maximum depolymerisation rate correlates with the initial concentrations of enzyme and substrate,E_oandS_o, and the enzyme kinetic constantsV_mandK_mthrough a hyperbola similar to that of Michaelis-Menten. TheK_mdetermined forB. subtilisβ-glucanase was rather low, about 0·99 g β-glucan/l, when compared with those corresponding to (1→3),(1→4)-β-d-glucanase from different malts, which were, in turn, practically identical at about 2·92 g β-glucan/l. Experiments with barley (1→3),(1→4)-β-d-glucans of different high initial molecular weights showed that initial molecular weight had no influence on the kinetics. Thus, this new methodology permits the determination of (1→3),(1→4)-β-d-glucanase activity in a direct way, i.e. the amount of (1→3),(1→4)-β-d-glucan degraded per amount of enzyme (or malt) per unit of time. Moreover, since it is insensitive to the initial molecular weight of the substrate, it seems to be well-suited for inter-laboratory comparisons of (1→3),(1→4)-β-d-glucanase activities.     

Report of the joint meeting of the Potato Section of EUCARPIA and the Section Breeding and varietal assessment of the EAPR, 3–7 July, 2000, Warsaw (Poland)

Report

Report of the joint meeting of the Potato Section of EUCARPIA and the Section Breeding and varietal assessment of the EAPR, 3–7 July, 2000, Warsaw (Poland)     

Isolation and Total Synthesis of Stolonines A–C,Unique Taurine Amides from the Australian Marine Tunicate Cnemidocarpa stolonifera

Cnemidocarpa stolonifera is an underexplored marine tunicate that only occurs on the tropical to subtropical East Coast of Australia, with only two pyridoacridine compounds reported previously. Qualitative analysis of the lead-like enhanced fractions of C. stolonifera by LC-MS dual electrospray ionization coupled with PDA and ELSD detectors led to the identification of three new natural products, stolonines A–C (1–3), belonging to the taurine amide structure class. Structures of the new compounds were determined by NMR and MS analyses and later verified by total synthesis. This is the first time that the conjugates of taurine with 3-indoleglyoxylic acid, quinoline-2-carboxylic acid and β-carboline-3-carboxylic acid present in stolonines A–C (1–3), respectively, have been reported. An immunofluorescence assay on PC3 cells indicated that compounds 1 and 3 increased cell size, induced mitochondrial texture elongation, and caused apoptosis in PC3 cells.     

Block copolymers containing poly (3-hydroxybutyrate-co-3-hydroxyvalerate) and poly (<Emphasis Type="Italic">ɛ</Emphasis>-caprolactone) units: Synthesis,characterization and thermal degradation

Biodegradable block copolymers containing poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and poly (ɛ-caprolactone) (PCL) units (PHCLs) with different contents of PCL block were synthesized successfully by using telechelic hydroxylated PHBV (PHBV-diol) with low molecular weight as a macroinitiator to initiate ring-opening bulk polymerization of ɛ-caprolactone (ɛ-CL). The chemical structure and molecular weight were characterized by 1H NMR, FTIR and GPC. The PHBV and PCL blocks in PHCLs were miscible in amorphous state, and formed separate crystalline phases with lower crystallinity than corresponding homopolymers, which was characterized by DSC and WAXD. The results of TGA showed that PHCLs underwent a two-step thermal degradation process. The thermal degradation process of PCL blocks was significantly different from PCL homopolymers. The activation energies of thermal degradation of PCL blocks calculated by Horowitz and Metzger method were much higher than that of each step of thermal degradation of PCL homopolymers.     

Overexpression and Characterization of a Novel Thermostable β-Agarase YM01-3, from Marine Bacterium Catenovulum agarivorans YM01T

Genome sequencing of Catenovulum agarivorans YM01^T reveals 15 open-reading frames (ORFs) encoding various agarases. In this study, extracellular proteins of YM01^T were precipitated by ammonium sulfate and separated by one-dimensional gel electrophoresis. The results of in-gel agarase activity assay and mass spectrometry analysis revealed that the protein, YM01-3, was an agarase with the most evident agarolytic activity. Agarase YM01-3, encoded by the YM01-3 gene, consisted of 420 amino acids with a calculated molecular mass of 46.9 kDa and contained a glycoside hydrolase family 16 β-agarase module followed by a RICIN superfamily in the C-terminal region. The YM01-3 gene was cloned and expressed in Escherichia coli. The recombinant agarase, YM01-3, showed optimum activity at pH 6.0 and 60 °C and had a K_m of 3.78 mg mL⁻¹ for agarose and a V_max of 1.14 × 10⁴ U mg⁻¹. YM01-3 hydrolyzed the β-1,4-glycosidic linkages of agarose, yielding neoagarotetraose and neoagarohexaose as the main products. Notably, YM01-3 was stable below 50 °C and retained 13% activity after incubation at 80 °C for 1 h, characteristics much different from other agarases. The present study highlights a thermostable agarase with great potential application value in industrial production.     

Synthesis and α-glucosidase inhibitory mechanisms of bis(2,3-dibromo-4,5-dihydroxybenzyl) ether, a potential marine bromophenol α-glucosidase inhibitor

Bis(2,3-dibromo-4,5-dihydroxybenzyl) ether (BDDE), derived from the marine algae, is a potential α-glucosidase inhibitor for type 2 diabetes treatment. In the present study, a synthetic route was established as a valid approach to obtain BDDE. Fluorescence spectra, circular dichroism spectra and molecular docking methods were employed to elucidate the inhibitory mechanisms of BDDE against α-glucosidase. The results showed that BDDE could be prepared effectively and efficiently with the established synthetic methods. Synthetic BDDE bound with α-glucosidase and induced minor conformational changes of the enzyme. The docking results indicated the interaction between BDDE and α-glucosidase was driven by both hydrophobic forces and hydrogen bonds. The docked BDDE molecule was completely buried in the α-glucosidase binding pocket with part of the molecule reaching the catalytic center and overlapping with the position of glucose, and the rest of the molecule extending towards protein surface. This study provides useful information for the understanding of the BDDE-α-glucosidase interaction and for the development of novel α-glucosidase inhibitors.     

A nucleotide substitution at the 5′ splice site of intron 1 of rice HEADING DATE 1(HD1) gene homolog in foxtail millet,broadly found in landraces from Europe and Asia

We investigated genetic variation of a rice HEADING DATE 1(HD1) homolog in foxtail millet.First, we searched for a rice HD1 homolog in a foxtail millet genome sequence and designed primers to amplify the entire coding sequence of the gene. We compared full HD1 gene sequences of 11 accessions(including Yugu 1, a Chinese cultivar used for genome sequencing) from various regions in Europe and Asia, found a nucleotide substitution at a putative splice site of intron 1, and designated the accessions with the nucleotide substitution as carrying a splicing variant. We verified by RT-PCR that this single nucleotide substitution causes aberrant splicing of intron 1. We investigated the geographical distribution of the splicing variant in 480 accessions of foxtail millet from various regions of Europe and Asia and part of Africa by d CAPS and found that the splicing variant is broadly distributed in Europe and Asia. Differences of heading times between accessions with wild type allele of the HD1 gene and those with the splicing variant allele were unclear. We also investigated variation in 13 accessions of ssp. viridis, the wild ancestor, and the results suggested that the wild type is predominant in the wild ancestor.