共查询到20条相似文献,搜索用时 15 毫秒
1.
Masaru Ohsaku Junya Izumi Akiar Imamura 《International journal of biological macromolecules》1984,6(5):234-240
In order to investigate the relationship existing between the electronic structures of collagen and its biochemical functions in vivo, the semiempirical CNDO/2 SCF MO calculations were carried out on several model polymers of collagen, (Gly-Pro)n, (Gly-Hyp)n, (Ala-Pro)n, (Ala-Hyp)n, (Gly-Pro-Gly)n, (Gly-Hyp-Gly)n, (Gly-Pro-Pro)n and (Gly-Pro-Hyp)n. Geometries of the skeleton of these polymers were assumed to be the same as those of poly(l-proline) I (cis) and II (trans) and the calculations were performed only on infinite polymers in a single chain. The results show that the cis form is always more stable than the trans form for all the polymers treated. This energy difference between the cis and trans forms depends, for example, on the kind of amino acid residue, Gly or Ala, but this could not be seen in the Pro or Hyp residue. The flexibility or mobility of the collagen structure was explained using the energy difference between the cis and trans forms of the polymers, i.e. the cis-trans conversion of the collagen was discussed in connection with the energy difference. The reason why the collagen has the constitution of (Gly-Pro-Hyp)n is briefly discussed. 相似文献
2.
Craig C. McLauchlan Michael P. Weberski Jr. Bradley A. Greiner 《Inorganica chimica acta》2009,362(8):2662-1093
The complexes (Tpms)VCl2(DMF) (1), and (Tpms)VOCl(DMF) (2), have been synthesized and characterized. Complex 2 has also been structurally characterized via X-ray diffractometry. The vanadium(IV) center possesses a square pyramidal/distorted octahedral geometry with a facially coordinating Tpms− ligand in a κ3-N,N,O coordination mode. The complex is the first structurally characterized example of a vanadium(IV) complex with Tpms−. Complex 2 shows catalytic activity towards oxidation of 3,5-di-tert-butyl catechol and also exhibits phosphatase inhibition characteristics on alkaline phosphatase. Tpms− = trispyrazolylmethanesulfonate; DMF = N,N-dimethylformamide. 相似文献
3.
Ivan Kanev 《Systematic parasitology》1994,28(2):125-144
The life-cycle of Echinostoma revolutum (Froelich, 1802) Dietz, 1909 has been completed experimentally beginning with infected snails collected at the type-locality, near Erlangen, Germany. Based on the specimens obtained, each stage of the life-cycle has been redescribed. Important taxonomic features are discussed and hitherto unknown characteristics are described. Synonyms for E. revolutum are: Fasciola revoluta Froelich, 1802; Echinostoma paraulum Dietz, 1909; E. audyi Lie & Umathevy, 1965; and E. ivaniosi Mohandas, 1973. Adults and larvae described as E. revolutum in other works are found to be identical with Echinostoma echinatum (Zeder, 1803), E. trivolvis (Cort, 1914), E. jurini (Skvortsov, 1924), E. caproni Richard, 1964, Moliniella anceps (Molin, 1859), Echinochasmus beleocephalus (Linstow, 1873) and other echinostome species. For nearly a century, incorrect morphological, biological, life-cycle and host information has been attributed to E. revolutum, and at times these data have contributed to the diagnoses of the species. Occasionally, authors actually working with E. revolutum have ascribed their results to other species. Based on extensive experimental life-cycle studies beginning with infected snails from type-localities, it is shown that (1) the first intermediate host is a lymnaeid snail; (2) the second intermediate hosts are various pulmonate and prosobranch snails, mussels, frogs and freshwater turtles; (3) the final hosts are birds; (4) E. revolutum cercariae and adults have 37 collar spines; (5) the species occurs only in Europe and Asia; (6) Cercaria echinata Siebold, 1937, Echinostoma echinatum (Zeder, 1803) and E. jurini (Skvortsov, 1924) are the closely related 37-spined allies in Europe; and (7) species specific characteristics are expressed only in the larvae and the host-parasite relationships. The adults of E. revolutum cannot be identified using morphological criteria and it is proposed that worms with 37 collar spines belonging to the genus Echinostoma and occurring in naturally infected birds in Europe and Asia be referred to an “E. revolutum group.” 相似文献
4.
5.
Sarcophaga (Sarcorohdendorfia) gracilior (Chen, 1975) is documented from specimens collected in Hubei Province, China, using morphological characters and wing interference patterns (WIPs). The female of S. (S.) gracilior is described for the first time, the male is redescribed, and both sexes are photographed. The distribution of the species is updated. 相似文献
6.
Data on natural enemies of psyllids are rare and can usually be found in papers about economically significant species. During an investigation of psyllid fauna in Serbia, natural enemies were investigated, too. True bugs were the most numerous among them. From 28 psyllid species, 21 species of true bugs from families Anthocoridae and Miridae were reared. Seven species of Anthocoridae were identified: Anthocoris amplicollis (Horváth, 1839), Anthocoris confusus Reuter, 1884, Anthocoris nemoralis (Fabricius, 1794), Anthocoris nemorum (Linnaeus, 1761), Orius majusculus Reuter, 1884, Orius minutus (Linnaeus, 1758) and Orius niger Wolff, 1811. The following 14 species of Miridae were identified: Atractotomus mali Meyer-Dür, 1843, Campylomma verbasci (Meyer-Dür, 1843), Deraeocoris flavilinea (A. Costa, 1862), Deraeocoris ruber (Linnaeus, 1758), Deraeocoris lutescens (Schilling, 1836), Heterocordylus genistae (Scopoli, 1763), Hypseloecus visci (Puton, 1888), Malacocoris chlorizans Panzer, 1794, Miris striatus (Linnaeus, 1758), Orthotylus marginalis Reuter, 1884, Psallus assimilis Stichel, 1956, Psallus quercus Kirschbaum, 1856, Psallus flavellus Stichel, 1933 and Pseudoloxops coccinea (Meyer-Dür, 1843). The aim of the research was to provide list of true bugs recorded as predators of psyllids in order to preserve their diversity and significance, especially on cultivated plants. 相似文献
7.
Om P. Mishra Nicholas Simmons Sonia Tyagi Ralph Pietrofesa Vladimir V. Shuvaev Roman A. Valiulin Philipp Heretsch K.C. Nicolaou Melpo Christofidou-Solomidou 《Bioorganic & medicinal chemistry letters》2013,23(19):5325-5328
Secoisolariciresinol diglucosides (SDGs) (S,S)-SDG-1 (major isomer in flaxseed) and (R,R)-SDG-2 (minor isomer in flaxseed) were synthesized from vanillin via secoisolariciresinol (6) and glucosyl donor 7 through a concise route that involved chromatographic separation of diastereomeric diglucoside derivatives (S,S)-8 and (R,R)-9. Synthetic (S,S)-SDG-1 and (R,R)-SDG-2 exhibited potent antioxidant properties (EC50 = 292.17 ± 27.71 μM and 331.94 ± 21.21 μM, respectively), which compared well with that of natural (S,S)-SDG-1 (EC50 = 275.24 ± 13.15 μM). These values are significantly lower than those of ascorbic acid (EC50 = 1129.32 ± 88.79 μM) and α-tocopherol (EC50 = 944.62 ± 148.00 μM). Compounds (S,S)-SDG-1 and (R,R)-SDG-2 also demonstrated powerful scavenging activities against hydroxyl [natural (S,S)-SDG-1: 3.68 ± 0.27; synthetic (S,S)-SDG-1: 2.09 ± 0.16; synthetic (R,R)-SDG-2: 1.96 ± 0.27], peroxyl [natural (S,S)-SDG-1: 2.55 ± 0.11; synthetic (S,S)-SDG-1: 2.20 ± 0.10; synthetic (R,R)-SDG-2: 3.03 ± 0.04] and DPPH [natural (S,S)-SDG-1: EC50 = 83.94 ± 2.80 μM; synthetic (S,S)-SDG-1: EC50 = 157.54 ± 21.30 μM; synthetic (R,R)-SDG-2: EC50 = 123.63 ± 8.67 μM] radicals. These results confirm previous studies with naturally occurring (S,S)-SDG-1 and establish both (S,S)-SDG-1 and (R,R)-SDG-2 as potent antioxidants and free radical scavengers for potential in vivo use. 相似文献
8.
Ostracod association from the Upper Triassic (Tropites dilleri zone of the Carnian stage) of the sedimentary succession (Mufara Formation) exposed along the east side of Monte Scalpello (Catenanuova, central eastern Sicily) has been studied for the first time. The specimens, silicified, are rare but well preserved and often consist of complete carapaces. They belong to eight families: Healdiidae, Cavellinidae, Bairdiidae, Acratiidae, Bythocyprididae, Pontocyprididae, Judahellidae, Glorianellidae. Twenty-three taxa have been listed; the family Bairdiidae is the most represented among all the others with fifteen species. Four species are new: Bairdia scaliae n. sp., Acratia maugerii n. sp., “Anchistrocheles” gemmellaroi n. sp. and Judahella? montanarii n. sp. Other species are left in open nomenclature because of the lack of specimens. 相似文献
9.
《Inorganica chimica acta》1988,147(1):99-102
K2PtCl4 reacts with L-lysine and with D,L-diaminiopropionic acid (Dap) forming the neutral complexes [PtCl2(N,O-Lys)]·H20 (1) and [PtCl2(N,O-Dap)], (2) respectively.Compound 1 is monoclinic, space group P21 with a = 11.262(3), b = 11.041(2), c = 9.690(2) Å, β = 102.07(5)°, V = 1178(1) Å3 and Z = 4. Compound 2 is monoclinic, space group P21/n with a = 8.777(1), b = 10.615(2), c = 7.947(1) Å, β = 94.98(3)°, V = 738(1) Å3 and Z = 4. In both compounds, the zwitterionic ligands form an N,O-five membered chelate with the platinum atom. Structures 1 and 2 were refined to R values of 3.3% and 6.3% respectively. 相似文献
10.
The present paper deals with a new species of the genus Lithobius Leach, 1814, Lithobius (Monotarsobius) songi sp. n.(Lithobiomorpha: Lithobiidae) recently discovered in Hebei Province, China. Morphologically it resembles Lithobius (Monotarsobius) holstii (Pocock, 1895) from China and Japan but could be well distinguished from latter by havinga Tömösváry’s organ slightly smaller than the adjoining ocelli, different leg plectrotaxy and tridentate claw of female gonopods. A key to the Chinese Lithobius (Monotarsobius)species is presented. 相似文献
11.
B. Christian Schmidt 《ZooKeys》2015,(527):103-126
The Lacinipolia
vicina (Grote) species complex, previously consisting of Lacinipolia
vicina, Lacinipolia
teligera (Morrison), Lacinipolia
pensilis (Grote), and Lacinipolia
subalba Mustelin is revised to six species: Lacinipolia
vicina (eastern USA), Lacinipolia
teligera (southern Great Plains), Lacinipolia
pensilis (Pacific Northwest and northern Rocky Mountains), Lacinipolia
acutipennis (Grote), stat. rev. (= Lacinipolia
subalba
syn. n.) (western North America), Lacinipolia
sareta (Smith), stat. rev. (Canada and western USA) and Lacinipolia
dimocki, sp. n. (California and Pacific Northwest). Lectotypes are designated for Lacinipolia
vicina, Lacinipolia
teligera and Lacinipolia
pensilis. 相似文献
12.
A short review of main cytogenetic features of insects belonging to the sister neuropteran families Myrmeleontidae (antlions) and Ascalaphidae (owlflies) is presented, with a particular focus on their chromosome numbers and sex chromosome systems. Diploid male chromosome numbers are listed for 37 species, 21 genera from 9 subfamilies of the antlions as well as for seven species and five genera of the owlfly subfamily Ascalaphinae. The list includes data on five species whose karyotypes were studied in the present work. It is shown here that antlions and owlflies share a simple sex chromosome system XY/XX; a similar range of chromosome numbers, 2n = 14-26 and 2n = 18-22 respectively; and a peculiar distant pairing of sex chromosomes in male meiosis. Usually the karyotype is particularly stable within a genus but there are some exceptions in both families (in the genera Palpares and Libelloides respectively). The Myrmeleontidae and Ascalaphidae differ in their modal chromosome numbers. Most antlions exhibit 2n = 14 and 16, and Palparinae are the only subfamily characterized by higher numbers, 2n = 22, 24, and 26. The higher numbers, 2n = 20 and 22, are also found in owlflies. Since the Palparinae represent a basal phylogenetic lineage of the Myrmeleontidae, it is hypothesized that higher chromosome numbers are ancestral for antlions and were inherited from the common ancestor of Myrmeleontidae + Ascalaphidae. They were preserved in the Palparinae (Myrmeleontidae), but changed via chromosomal fusions toward lower numbers in other subfamilies. 相似文献
13.
《Annales de Paléontologie》2001,87(2):99-117
A proboscidean skull from Cheparawa, (Muruyur Formation, Kenya), differs markedly from those of Eurasian Choerolophodon (C. pentelici, C. dhokpathanensis). It is morphologically and metrically close to the holotype of Choerolophodon kisumuensis (MacInnes) a partial skull from Maboko, much of which has been reconstructed in plaster of Paris. The more complete remains of this species now available indicate that it should be placed in a genus separate from Choerolophodon. The new genus Afrochoerodon is erected for it. Choerolophodon ngorora from Ngorora and Fort Ternan (Kenya), Choerolophodon zaltaniensis from Gebel Zelten (Libya) and Choerolophodon chioticus from Chios, Greece, should be transferred to the genus Afrochoerodon. Late Miocene specimens from Nakali, Kenya are probably referrable to the genus Choerolophodon. Fossils from Burji-Soyama (Ethiopia) hitherto assigned to Choerolophodon sp. are excluded from the subfamily Choerolophodontinae. 相似文献
14.
15.
Ana M. González-Tizón Verónica Rojo Joaquín Vierna K. Thomas Jensen Emilie Egea Andrés Martínez-Lage 《Helgoland Marine Research》2013,67(1):73-82
The European razor shell Ensis minor (Chenu 1843) and the American E. directus (Conrad 1843) have a diploid chromosome number of 38 and remarkable differences in their karyotypes: E. minor has four metacentric, one metacentric–submetacentric, five submetacentric, one subtelocentric and eight telocentric chromosome pairs, whereas E. directus has three metacentric, two metacentric–submetacentric, six submetacentric, six subtelocentric and two telocentric pairs. Fluorescent in situ hybridisation (FISH) using a major ribosomal DNA probe located the major ribosomal genes on one submetacentric chromosome pair in both species; FISH with a 5S ribosomal DNA (5S rDNA) probe rendered one chromosomal (weak) signal for E. minor and no signal for E. directus, supporting a more dispersed organisation of 5S rDNA compared to the major ribosomal genes. The vertebrate telomeric sequence (TTAGGG) n was located on both ends of each chromosome, and no interstitial signals were detected. In this work, a comparative karyological analysis was also performed between the four Ensis species analysed revealing that the three European species studied so far, namely E. minor, E. siliqua (Linné 1758) and E. magnus Schumacher 1817 show more similarities among them than compared to the American species E. directus. In addition, clear karyotype differences were found between the morphologically similar species E. minor and E. siliqua. 相似文献
16.
Jörg Maletz 《Pal?ontologische Zeitschrift》1996,70(1-2):203-212
The horizontal didymograptid speciesDidymograptus (Expansograptus) suecicus Tullberg,D. (E.) holmi Törnquist andD. (E.) similis (J. Hall) are redescribed using the type material and additional specimens. Their exact proximal structures are revealed for the first time from relief material. All three species can easily be differentiated taxonomically and also show differences in their biostratigrapnic distribution. 相似文献
17.
Species of Laccaria are described from the eastern Himalayas, in the Xizang Autonomous Region of China, more commonly known as Tibet. Specimens were collected during several expeditions over a 12-year time span. Nuclear ribosomal internally transcribed spacer regions 1 and 2 including and 5.8S (ITS) as well as the 5' end of the large subunit (28S) sequence data were generated for 22 specimens from Tibet and analyzed in a dataset of 115 Laccaria samples. The results documented seven species from this region, five of which represent currently undescribed species. The taxonomy of Tibetan Laccaria is discussed, five new species are proposed, and an artificial key that includes extralimital species from Asia is provided. 相似文献
18.
W. J. Kennedy 《Pal?ontologische Zeitschrift》1985,59(3-4):211-222
A revision of the surviving “Barroisiceras” specimens from Cameroon described by SOLGER (1904) suggests thatBarroisiceras brancoi, type species ofSolgerites REESIDE, 1932, including varietiesmitis andarmatus of SOLGER, andBarroisiceras hoberfellneri alstadenensis SOLGER non SCHLüTER are variants of a single species and thatSolgerites is a synonym ofForresteria (Forresteria) REESIDE, 1932, of whichEboroceras BASSE, 1947 also is a synonym. 相似文献
19.
Basu Baul TS Mizar A Chandra AK Song X Eng G Jirásko R Holcapek M de Vos D Linden A 《Journal of inorganic biochemistry》2008,102(9):1719-1730
A series of cis-bis{5-[(E)-2-(aryl)-1-diazenyl]quinolinolato}di-n-butyltin(IV) complexes has been synthesized and characterized by 1H-, 13C-, 119Sn NMR, ESI-MS (electrospray ionization mass spectrometry), IR and 119mSn Mössbauer spectroscopic techniques in combination with elemental analyses. The structures of four di-n-butyltin(IV) complexes, viz., nBu2Sn(L3)2 (3), nBu2Sn(L4)2 (4), nBu2Sn(L5)2 (5) and nBu2Sn(L7)2 · 0.5C6H6 (7) (LH = 5-[(E)-2-(aryl)-1-diazenyl)quinolin-8-ol) were determined by single crystal X-ray diffraction. In general, the complexes were found to adopt a distorted cis-octahedral arrangement around the tin atom. These complexes retain their solid-state structure in non-coordinating solvent as evidenced by 119Sn and 13C NMR spectroscopic results. The in vitro cytotoxicity of di-n-butyltin(IV) complexes (3-8) is reported against seven well characterized human tumour cell lines. The basicity of the two quinolinolato donor N and O atoms of the ligands are discussed in relation to the cytotoxicity data. 相似文献
20.
Christian Lukhaup 《ZooKeys》2015,(502):1-10
A new species, Cherax (Astaconephrops) pulcher
sp. n., from Hoa Creek, close to the village Teminabuan in the southern-central part of the Kepala Burung (Vogelkop) Peninsula, West Papua, Indonesia, is described, figured and compared with the morphologically closest species, Cherax
boesemani Lukhaup & Pekny, 2008. 相似文献