Thiosugars. X. Novel Nucleoside Analogues Derived from 4-Thio-L-lyxofuranose

Abstract

1-O-Acetyl-2,3,5-tri-O-benzyl-4-thio-L-lyxofuranose 1 was transformed into O-benzyl- and O-acetyl-protected 1-(4-thio-L-lyxofuranosyl) nucleoside derivatives by use of the TMSOTf method. Debenzylation with boron tribromide or deacetylation with sodium methoxide yielded the corresponding pyrimidine (7–11, 17, 18, 26 and 27) and purine (29 and 34) nucleoside analogues. The anomeric configurations were determined by NMR spectroscopy and, in the case of the 5-halo- (7–9) and nitrouridine derivative 11 and the 6-methylcytidine derivative 27, by X-ray structural analyses. – The unprotected nucleosides were not antivirically inhibitory at 250 µM.     

Folsomia (Collembola: Isotomidae) of China. II. heterocellata group

An annotated list of species of the Folsomia heterocellata group recorded in China is given. Folsomia cephalota n. sp., F. dorsomediaseta n. sp., F. longiseta n. sp., F. manubriopilosa n. sp., F. longdeica n. sp., and F. plenosensilla n. sp. are characterized by having a simple maxillary palp, four prelabral setae and no eyes. They differentiate mainly by characteristics of the furca. We report other species of the group which are recorded for the first time in China: Folsomia tianshanica Martynova, 1969, F. pseudovtorovi Potapov & Gulgenova, 2013, and F. pseudodecemoculata Stebaeva, 1971. This excludes F. wanxianensis Ji, Ding & Chen, 2007, for which we provide morphological remarks based on the type material. The group is mainly distributed in the central part of China (Chongqing, Gansu, southern part of Inner Mongolia, Ningxia and Shaanxi provinces). A key to all blind species with a simple maxillary palp is given.     

Fatty Acid n-Propyl and Ethyl Esters in the Volatile Oil from Dentcorn,Zea mays L. var. indentata,Silage

(+)-Marmelo Lactones A(VA) and B (VB) were synthesized from erythro-γ-methyl-l-glutamic acid (IA) and threo acid (IB), respectively. The absolute configurations of natural marmelo lactones were thus determined to be (2R, 4S) for (+)-marmelo lactone A and (2R, 4R) for ( – )-marmelo lactone B.     

Contributions to the Flora of Spitsbergen,especially of Red bay,from the Collections of W. S. Bruce,F.R.S.G.S., Naturalist to the Prince of Monaco's Expeditions of 1898 and 1899

Background: Prescribed burning in peatlands is controversial due to concerns over damage to their ecological functioning, particularly regarding their key genus Sphagnum. However, empirical evidence is scarce.

Aims: The aim of the article is to quantify Sphagnum recovery following prescribed burns.

Methods: We completed nine fires at a raised bog in Scotland, achieving a range of fire severities by simulating drought in some plots. We measured Sphagnum cover and chlorophyll fluorescence F_v/F_m ratio (an estimate of photosynthetic capacity) up to 36 months post-fire.

Results: Cover of dominant Sphagnum capillifolium was similar in unburnt and burnt plots, likely due to its high moisture content which prevented combustion. Burning decreased S. capillifolium F_v/F_m 5 months after fire from 0.67 in unburnt plots to 0.44 in low fire severity plots and 0.24 in higher fire severity (drought) plots. After 22 months, F_v/F_m in burnt plots showed a healthy photosynthetic capacity of 0.76 and no differences between severity treatments. Other Sphagnum species showed similar post-fire recovery though their low overall abundance precluded formal statistical analysis.

Conclusions: S. capillifolium is resilient to low–moderate fire severities and the same may be true for a number of other species. This suggests that carefully applied managed burning can be compatible with the conservation of peatland ecosystem function.     

Pohlia andrewsii J. Shaw in the U.S.S.R.

Abstract

P. andrewsii appears to be widespread in the arctic regions of the U.S.S.R. and also in mountains of southern Siberia, the Altai Mountains. Except in the mountains of Central and Northern Europe the range of P. andrewsii does not overlap with P. annotina and P. camptotrachela.     

Abraracourcix curvivenatus n. gen. n. sp. from the Lowermost Eocene Oise amber (Hemiptera: Fulgoromorpha: Ricaniidae)

An extinct genus Abraracourcix n. gen. with A. curvivenatus n. sp. is described based on the specimen from the Lowermost Eocene Oise amber. The venation characters and possible hostplant relationships, as well as taxonomic position and biogeographical pattern of recent Pochazoides generic group are discussed.     

Studies in Neotropical Burseraceae. II. Generic limits in New World Protieae and Canarieae

Trattinnickia is closely related toDacryodes and is transferred to the tribe Canarieae. Additional characters are proposed to supplement the weak characters that traditionally have been used to separateCrepidospermum andTetragastris fromProtium. The assumed “intermediate” genusParaprotium is shown to be an unnatural assemblage and is here merged withProtium. This revised concept of generic limits in the Neotropical Protieae and Canarieae leads to the following new combinations:Tetragastris occhionii (Rizzini) Daly,Protium pilosum (Cuatrec.) Daly,Protium nitidifolium (Cuatrec.) Daly,Protium vestitum (Cuatrec.) Daly, andDacryodes cuspidata (Cuatrec.) Daly. A key to the Neotropical genera of Burseraceae is provided.     

I. Introduction

Background: Past research and ecological theory supports the hypothesis that alpine plants should be predominantly clonal, long-lived and reproduce by seed infrequently.

Aims: To challenge the entrenched view that alpine seedling establishment is uncommon and perhaps unsuccessful in maintaining alpine plant populations.

Methods: We looked for patterns in seedling establishment across a stress gradient of alpine sites and tested the notion that natural seedling recruitment would be reduced at higher altitudes due to a combination of stressful environmental conditions such as frosts, wind and extended snow cover.

Results: Seedlings were common at all study sites and there was a partial trend in mean seedling density with altitude. Seedling emergence was best predicted by a combination of altitude, plant litter and soil wilting point. Many seedlings survived to become established plants (37–61%) but there was no significant relationship between establishment and altitude. There was low similarity between the seedling flora and the standing vegetation, suggesting that patterns in seedling establishment are unlikely to be driving the patterns in the standing vegetation assemblage.

Conclusions: Although Australian alpine species predominantly reproduce vegetatively, this study shows that many plants depend on recruitment from seed in order to become established.     

New Acyclic Quinoxaline Nucleosides. Synthesis and Anti-Hiv Activity

A series of acyclonucleosides substituted 1-(4,5-dihydroxypentyl) (13-8) and 2-(4,5-dihydroxypentyloxy)quinoxalines (19-24) were synthesized by the sharpless asymmetric dihydroxylation of the derivatives 1-6 and 7-12, respectively. Treatment of the quinoxaline base 26 with (R)-2,2-dimethyl-1,3-dioxolan-4-ylmethyl-p-toluenesulfonate (27) in the presence of NaH/DMF furnished 28. Acid hydrolysis of 28 gave 1-(2,3-dihydroxypropyl)-6,7-dimethyl-quinoxaline-2-one (29). Alternatively, 29 was prepared by sharpless dihydroxylation of 30. All the compounds were evaluated for their in vitro anti-HIV-1 and HIV-2 in MT-4 cell and found inactive, except 29, which showed inhibition of HIV-1 with EC₅₀ value of 0.15 ± 0.1 μg/ml and a therapeutic index (SI) of 73.     

Calymperes schmidtii Broth. in J. Schmidt and C. subintegrum Broth. in J. Schmidt,two distinct species from Malesia

Abstract

Calymperes schmidtii Broth. in J. Schmidt and C. subintegrum Broth. in J. Schmidt, hitherto regarded as conspecific, are shown to represent distinct species.     

Bryophytes of St Helena,South Atlantic Ocean. 1. Three new species of Cololejeunea (Jungermanniales,Lejeuneaceae), C. dianae sp. nov., C. sanctae-helenae sp. nov. and C. grossestyla sp. nov.

Abstract

Three new species of Cololejeunea, C. dianae M. Wigginton, C. sanctae-helenae M. Wigginton and C. grossestyla M. Wigginton are described and illustrated from St Helena, South Atlantic Ocean. Details of their distributions are provided, and differences between the new taxa and other species of Cololejeunea are discussed. This is also the first report of the genus Cololejeunea from St Helena.     

Plagiochila atlantica F. Rose,sp. nov.—P. amhagiosa auct.

Abstract

The Irish plant which, following Mitten, has commonly been referred to as Plagiochila ambagiosa Mitt. is specifically different from the type of P. ambagiosa, and is therefore described as Plagiochila atlantica F. Rose, sp. nov. It is now known from very restricted areas in Western Ireland, Western Scotland and North-western France.     

Tyrosinase inhibitory activities of the compounds isolated from Neolitsea aciculata (Blume) Koidz.

This study was designed to investigate the mushroom tyrosinase inhibitory activity for the constituents isolated from Neolitsea aciculata. The stems of N. aciculata was extracted with aqueous ethanol and subjected to chromatographic separation, which led to the isolation of 11 compounds: methyl linoleate (1), catechin (2), epicatechin (3), afzelin-7-O-glucopyranoside (4), 2′,3′-di-(p-coumaroyl)afzelin (5), 2′-p-coumaroylafzelin (6), feruloyl tyramine (7), β-sitosterol (8), daucosterol (9), oleic acid (10), and trilaurin (11). Their structures were elucidated on the basis of spectroscopic studies as well as by comparison with the data available in the literature. Among these isolates, compounds 5 and 6 were identified as potent mushroom tyrosinase inhibitors with IC₅₀ values of 0.067 and 0.080 mM, respectively. The inhibition kinetics, analysed by Lineweaver–Burk plots, indicated that compounds 5 and 6 are competitive tyrosinase inhibitors when using l-tyrosine as a substrate. Notably, compounds 1–11 were isolated for the first time from this plant. These results provide evidence that this plant might be a potential source of anti-melanogenesis agents.     

A New Lignan Amide,Grossamide, from Bell Pepper (Capsicum annuum var. grossurri)

Two new phenolic amides, grossamide (7) and N-cis-feruloyl tyramine (2), have been isolated from the roots of bell pepper (Capsicum annuum var. grossum) together with p-aminobenzaldehyde (1), N-trans-feruloyl tyramine (3), N-trans-p-coumaroyl tyramine (4), N-trans-feruloyl octopamine (5), and N-trans-p-coumaroyl octopamine (6).     

Synthesis and Antileishmanial Activity of 3-Imidazolylalkylindoles. Part I

The present study was designed to investigate conazoles as new antileishmanial agents. Several 3-imidazolylalkylindoles were prepared under mild reaction conditions and pharmacomodulation at N1 and C5 of the indole ring and at the level of the alkyl chain (R) was carried out starting from the corresponding 3-formylindoles 7–10. All target imidazolyl compounds 38–52 were evaluated in vitro against Leishmania mexicana promastigotes; ketoconazole, amphotericin B and meglumine antimoniate were used as references. Eight out of fifteen compounds (40, 43, 44, 47, 48, 50, 51 and 52) exerted similar activity to ketoconazole, with IC₅₀ values in the range of 2.10–3.30?μg/mL. However the most potent compound, 1-(2-bromobenzyl)-3-(1H-imidazol-1-ylmethyl)-1H-indole (38), exhibited IC₅₀ value (0.011±0.003?μg/mL) 270-fold lower than that of ketoconazole. Four compounds (38, 43, 50 and 52) were also tested against intracellular amastigotes of L. mexicana; compound 38 exhibited the highest activity with an IC₅₀ value of 0.018±0.004?μg/mL.     

A review of the Malagasy endemic genus Cyrtolophus Fairmaire and description of Pseudocyrtolophus n. gen. (Coleoptera: Scarabaeidae: Rutelinae: Adoretini)

Summary

After lectotype designations for both names, the synonymy between Cyrtolophus grandicornis Fairmaire, 1895 and Cyrtolophus viduus Ohaus, 1912, n. syn., is proposed. Pseudocyrtolophus n. gen. is described to accommodate Cyrtolophus limbicollis Ohaus, 1912, its type species, and a second species, Pseudocyrtolophus australis n. sp., which is described and compared to its most related species. The lectotype of Cyrtolophus limbicollis is designated. All species are illustrated. A map showing their distribution in Madagascar is given.     

Validation of Hygrohypnum Lindb. sect. Dilatatae Szafr.

Abstract

A number of chemical habitat parameters for the species Scorpidium scorpioides, S. cossonii and S. revolvens were investigated in three areas in northern and southern Sweden. S. revolvens occurs in a much narrower range of some parameters, especially pH and conductivity, than the other two species. When pH and conductivity are considered together, S. revolvens and S. cossonii are almost completely mutually exclusive.     

Species group taxa of longhorned beetles (Coleoptera,Cerambycidae) described by N. N. Plavilstshikov and their types preserved in the Zoological Museum of the Moscow State University and in the Zoological Institute of the Russian Academy of Sciences,St. Petersburg

The names of all 135 species-group taxa of Cerambycidae described by N. N. Plavilstshikov are listed. Types of all these taxa preserved in the Zoological Museum of the Moscow State University and in the Zoological Institute (St. Petersburg) are catalogued, with lectotypes and paralectotypes designated. New synonymies are proposed: Pseudosieversia rufa (Kraatz, 1879) = Macrorhabdium ruficollis Plavilstshikov, 1915, syn. n.; Pseudo sieversia Pic, 1902 = Macrorhabdium Plavilstshikov, 1915, syn. n.; Agapanthia angelicae Reitter, 1898 = A. jacobsoni Plavilstshikov, 1915, syn. n. Dorcadion arietinum phenax Jakovlev, 1900, stat. n. is a valid name of the taxon known before as D. arietinum strandi Plav. Alosterna tabacicolor subsp. tokatensis Pic, 1901 (= A. t. caucasica Plavilstshikov, 1936, syn. n.) is regarded as a valid name (nomen protectum), and A. chrysomeloides var. subvittata Reitter, 1885 is regarded a nomen oblitum, as well as Cortodera umbripennis var. pallidipes Pic, 1898, while C. ruthena Plavilstshikov, 1936 is nomen protectum. Vadonia bipunctata puchneri Holzschuh, 2007, stat. n. is widely distributed in southern Ukraine and southern Russia from Dnepropetrovsk to Rostov-on-Don, and in the North Caucasus; specimens of this subspecies, as also specimens of V. saucia (Mulsant et Godart, 1855), stat. rest., known from the southern Crimea, constitute a part of the type series of V. bipunctata mulsantiana (Plavilstshikov, 1936).     

Constituents with tyrosinase inhibitory activities from branches of Ficus erecta var. sieboldii King

Phytochemical investigation of the branches of Ficus erecta var. sieboldii King resulted in the isolation of eight constituents: p-hydroxybenzoic acid (1), methyl p-hydroxybenzoate (2), vanillic acid (3), methyl vanillate (4), syringic acid (5), β-sitosterol (6), α-amyrin acetate (7), and ethyl linoleate (8). Their chemical structures were identified via spectroscopic means as well as by comparing their data with literature values. Studies on tyrosinase inhibition activities were conducted for the isolated compounds. Among them, p-hydroxybenzoic acid (1) and methyl p-hydroxybenzoate (2) were identified as active tyrosinase inhibitors with IC₅₀ values of 0.98?±?0.042 and 0.66?±?0.025?mM, respectively, showing comparable activities to that of arbutin (IC₅₀?=?0.32?±?0.015?mM), a standard control. Inhibition kinetics, as analyzed by Lineweaver-Burk plots, indicated that compounds 1 and 2 were competitive inhibitors of diphenolase of mushroom tyrosinase. Notably, isolated compounds 1–8 were reported for the first time as constituents of F. erecta.     

Nucleosides and Nucleotides. 192. Toward the Total Synthesis of Cyclic ADP-Carbocyclic-Ribose. Formation of the Intramolecular Pyrophosphate Linkage by a Conformation-Restriction Strategy in a Syn-form Using a Halogen Substitution at the 8-Position of the Adenine Ring

Abstract

The synthesis of cyclic ADP-carbocyclic-ribose (2), as a stable mimic for cyclic ADP-ribose, was investigated. Construction of the 18-membered backbone structure was successfully achieved by condensation of the two phosphate groups of 19, possibly due to restriction of the conformation of the substrate in a syn-form using an 8-chloro substituent at the adenine moiety. SN2 reactions between an optically active carbocyclic unit 8, which was constructed by a previously developed method, and 8-bromo-N ⁶-trichloroacetyl-2′,3′-O-isopropylideneadenosine 9c gave N-1-carbocyclic derivative, which was deprotected to give 5′,5′-diol derivatives 18. When 18 was treated with POCl₃ in PO(OEt)₃, the bromo group at the 8-position was replaced to give N-1-carbocyclic-8-chloroadenosine 5′,5′-diphosphate derivative 19 in 43% yield. Treatment of 19 with 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride gave the desired intramolecular condensation product 20 in 10% yield. This is the first chemical construction of the 18-membered backbone structure containing an intramolecular pyrophosphate linkage of a cADPR-related compound with an adenine base.