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Syntheses of (Pro-Leu-Gly)n and (Leu-Pro-Gly)n, two synthetic polytripeptide analogues of the non-polar regions of collagen, via the corresponding tripeptide p-nitrophenyl-esters are described. The sequential polypeptide (Pro-Leu-Gly)10 was also obtained by solid-phase synthesis. In the following paper, conformational investigations on these polymers, both in solution and in solid state, will be described.  相似文献   

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Zhao S  Jia F  Balke M 《ZooKeys》2011,(94):61-71
Rhantus fengisp. n. from Mount Sejila, Xizang, China is described and illustrated. Laccoporus nigritulus (Gschwendtner, 1936) is redescribed and illustrated; Laccoporus viator Balfour-Browne, 1939, syn. n. is established as its junior subjective synonym.  相似文献   

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The conformational properties of (Pro-Leu-Gly)10, (Pro-Leu-Gly)n and (Leu-Pro-Gly)n were investigated both in solution and in solid state. By circular dichroism studies it was possible to demonstrate the formation of an ordered collagen-like structure for (Pro-Leu-Gly)n in hexafluroisopropanol-water mixtures and in ethylene glycol; (Leu-Pro-Gly)n assumes an ordered conformation only in ethylene glycol; (Pro-Leu-Gly)10 is unordered under all the conditions studied. X-ray diffraction patterns indicated that (Pro-Leu-Gly)n and (Leu-Pro-Gly)n assume a triple helical structure in solid state. In addition, the investigation of (Pro-Leu-Gly)n strongly suggests that this type of structure is a single chain triple helix. The X-ray patterns of (Pro-Leu-Gly)10 do not allow us to ascertain a collagen or polyproline II-like structure for this decatripeptide.  相似文献   

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A new species of Arenopontia (Neoleptastacus) is described on the basis of a single female collected from one sandy beach in Montenegro, Adriatic Sea. With the addition of the new species, the subgenus Neoleptastacus now includes 18 species throughout the world. At the end of this paper there is a key for their determination. Received: 20 March 1999 / Received in revised form: 15 September 1999 / Accepted: 21 September 1999  相似文献   

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The taxonomy of the Metopidae (Ciliophora, Armophorida) remains poorly understood since most of its members have not been studied by modern morphologic and molecular methods. Recent molecular investigations have indicated that the two most species-rich genera, Metopus and Brachonella, are likely nonmonophyletic with at least one well-supported 18S rDNA clade comprised of a species from each of these genera (Brachonella galeata and Metopus violaceus). We investigated these two species with silver impregnation and scanning electron microscopy. Both taxa share important morphologic characteristics not described in other species of Metopus or Brachonella. These synapomorphies include: (1) a diplostichomonad paroral membrane, (2) a bipartite adoral zone with a short buccal part composed of ordinary membranelles and a longer distal part composed of much smaller membranelles bearing a single cilium or none and extending the same length as the perzonal ciliary stripe. We transfer Brachonella galeata (Kahl, 1927) Jankowski, 1964 and Metopus violaceus Kahl, 1926 to genus Atopospira Jankowski, 1964 nov. stat. Pending detailed morphologic and molecular characterization, Brachonella campanula, B. cydonia and B. pyriforma, B. intercedens, and B. lemani remain in Brachonella Jankowski 1964.  相似文献   

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Nine specimens of Apus affinis (J.E. Gray) were studied at Franceville, Haut-Ogooué Province, Republic of Gabon, for the presence of helminth parasites. Two cestode species of the family Dilepididae were recorded. Pseudangularia gonzalezi n. sp. is distinguished from the most similar species P. europaea Georgiev & Murai, 1993 by having elliptical cirrus-sac, longer vagina, longer rostellar sheath and greater diameter of suckers. An identification key to the species of the genus Pseudangularia Burt, 1938 is proposed. The present study is the first record of the genus Pseudangularia in the Afrotropical Region. Our study confirms that, in dilepidids with vaginal sclerites from swifts, breaking off the cirrus after copulation is a frequent phenomenon. The genus Gibsonilepis n. g. is erected as monotypic for Vitta swifti Singh, 1952 (originally described from the same host species in India) and Gibsonilepis swifti n. comb. is proposed. Gibsonilepis n. g. is distinguished from Vitta Burt, 1938 by its highly elongate rostellum, rostellar sheath much bigger than rostellum, relatively small rostellar hooks possessing strongly developed guard, disc-shaped suckers with weak peripheral musculature and flat or convex central part, long and well-expressed neck, highly lobed two-winged ovary (lobes rounded) and presence of a band consisting of rows of spine-like microtriches along posterior margin of each proglottis. This is the first record of G. swifti in the Afrotropical Region. The separation of G. swifti from the genus Vitta (parasites of swallows) suggests that, contrary to previous opinions, no dilepidid genera are shared by Apodidae (swifts) and Hirundinidae (swallows).  相似文献   

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ABSTRACT The morphology and morphogenesis of Metopus hasei Sondheim, 1929 and M. inversus (Jankowski, 1964) n. comb, were investigated using live observation, silver impregnation, and scanning electron microscopy. Metopus has a spiral body organization and the ventral margin of the preoral dome bears five specialized ciliary rows, that form the so-called perizonal stripe. Division is homothetogenic, occurs in freely motile (i. e. non-encysted) condition, and includes a partial reorganization of the parental oral apparatus. During division, the complicated cell shape becomes ellipsoidal and all ciliary rows arrange meridionally. Stomatogenesis is entirely somatic (≅ pleurotelokinetal) and commences with the formation of kinetofragments in some dorsolateral kineties. The fragments become the opisthe's adoral membranelles, while the paroral membrane is generated by the left two perizonal ciliary rows, which proliferate kinetids intrakinetally. The perizonal stripe of the opisthe is generated by the three right parental perizonal kineties, which divide, and by two dorsolateral ciliary rows, which are added. The morphogenetic processes, especially the unique mode of formation of the paroral membrane, are used to define the order Metopida Jankowski, 1980 n. stat. more properly. The ontogenetic, ultrastructural, and sequence data available give no clear indication about metopid phylogeny, but definitely exclude metopids from the classical heterotrichs, with which they were classified for more than 100 years. Accordingly, we place the Metopida as incertae sedis in the subphylum Intramac-ronucleata Lynn, 1996.  相似文献   

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New host and locality records are given for Plagiorhynchus (Plagiorhynchus) charadrii (Yamaguti, 1939) Van Cleave, 1951 and P. (Prosthorhynchus) cylindraceus (Goeze, 1782) Schmidt & Kuntz, 1966. The uncertainty of identification of a plover host of P. (P.) charadrii as well as the origins of P. (P.) cylindraceus (found in Australia but not New Zealand) and its occurrence in both bird and mammal hosts are discussed. P. (P.) menurae (Johnston, 1912) Golvan, 1956 is redescribed, including the male, and new host, Menura alberti Bonaparte, and locality records are given. P. (P.) allisonae n. sp. is described from Haematopus ostralegus finschi (Martens) and H. unicolor (Forster) from the South Island of New Zealand. P. (P.) allisonae can be differentiated from its congeners by having a proboscis armature of 18-23 rows of 14-20 hooks, thorns of hooks shorter than simple roots with short manubria, eight tubular cement glands and eggs of 134-154 x 33-36 microm in size. The presence of P. (P.) gracilis Petrochenko, 1958 in Australia is questioned. New host and locality records are given for Porrorchis hylae (Johnston, 1914) Schmidt & Kuntz, 1967 and the northern distribution of P. hydromuris (Edmonds, 1957) Schmidt & Kuntz, 1967 confirmed.  相似文献   

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Analysis of microfossil silica phytoliths is becoming an increasingly important research tool for taxonomists, archaeobotanists, and paleoecologists. Expanded use of phytolith analysis by researchers is dependent upon development of phytolith systematics. In this study phytoliths produced by the inflorescence bracts from four species of wheat, Triticum monoccocum, T. dicoccon, T. dicoccoides, and T. aestivum, and two species of barley, Hordeum vulgare, and H. spontaneum, were analyzed using computer-assisted image and statistical analysis with the intent to develop taxonomic tools to distinguish among the taxa. A classification key based on significant differences among the mean morphometries of the inflorescence phytoliths produced by each species was created and tested. Discriminant analysis of the morphometries of several morphotypes of phytoliths was also conducted to determine whether this computer-assisted statistical procedure could be used as another method to classify the taxa and to determine which morphotypes have measurements that can best be used in discriminant functions. Test results indicated that, at the genus level, both the classification key and discriminant analysis of certain morphotypes of phytoliths were relatively reliable tools for distinguishing among phytoliths produced in the inflorescence bracts of the taxa considered. For distinguishing among the taxa at the species level, the classification key was most reliable. Of the discriminant analyses tested, that based on all the phytolith morphotypes combined was more reliable than those based on only one morphotype.  相似文献   

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Two marine urostylid ciliates, Anteholosticha multicirrata n. sp. and Anteholosticha pulchra (Kahl, 1932) Berger, 2003, were collected from South Korea. These species were identified based on morphology, morphogenesis, and SSU rRNA gene sequence comparison. Anteholosticha multicirrata n. sp. is characterized by the following features: body size 90–125 × 30–45 μm in vivo, shape slender to ellipsoidal in outline, with yellow‐greenish cortical granules distributed along and between dorsal kineties and cirri; single contractile vacuole positioned on left at mid‐body; three frontal, five to seven frontoterminal, one buccal, one to two pretransverse and four to six transverse cirri; three complete dorsal kineties; one left and one right marginal cirral row; about 117 macronuclear nodules; and three to four micronuclei observed during morphogenesis. In addition, based on the observations of morphogenesis, we found that A. pulchra has pretransverse cirri, which were not described in detail in previous studies. Nuclear small subunit ribosomal RNA (SSU rRNA) gene was used to analyse their phylogenetic relationship, and the gene tree supports that the genus Anteholosticha is a highly polyphyletic group.  相似文献   

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M W Van Dyke  P B Dervan 《Biochemistry》1983,22(10):2373-2377
The DNA binding sites for the antitumor, antiviral, antibiotics chromomycin, mithramycin, and olivomycin on 70 base pairs of heterogeneous DNA have been determined by using the (methidiumpropyl-EDTA)iron(II) [MPE x Fe(II)] DNA cleavage inhibition pattern technique. Two DNA restriction fragments 117 and 168 base pairs in length containing the lactose operon promoter-operator region were prepared with complementary strands labeled with 32P at the 3' end. MPE x Fe(II) was allowed to partially cleave the restriction fragment preequilibrated with either chromomycin, mithramycin, or olivomycin in the presence of Mg2+. The preferred binding sites for chromomycin, mithramycin, and olivomycin in the presence of Mg2+ appear to be a minimum of 3 base pairs in size containing at least 2 contiguous dG x dC base pairs. Many binding sites are similar for the three antibiotics; chromomycin and olivomycin binding sites are nearly identical. The number of sites protected from MPE x Fe(II) cleavage increases as the concentration of drug is raised. For chromomycin/Mg2+, the preferred sites on the 70 base pairs of DNA examined are (in decreasing affinity) 3'-GGG, CGA greater than CCG, GCC greater than CGA, CCT greater than CTG-5'. The sequence 3'-CGA-5' has different affinities, indicating the importance of either flanking sequences or a nearly bound drug.  相似文献   

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SYNOPSIS. Diophrys scutum , collected from four locations on the New Hampshire coast, ranged from 89–195 7mu; in length, 50–105 μ in width, and 68–88 μ in buccal cavity length. The end of the adoral zone of membranelles (AZM) extends 37–59 μ (average = 45.6 μ) posteriorly in a groove on the right side of the body. Dorsally are five rows of stiff cilia. The silverline system (Chatton-Llvoff technique) appears as a fine meshwork, entirely different from that found in Euplotes or Uronychia . There are two elongate macronuclei (Feulgen reaction) and several micronuclei. Diophrys peloetes n. sp., collected from one location in Alligator Harbor. Florida, ranged from 95–134 μ in length, 62–84 μ in width. and 60–80 μ in buccal cavity length. The terminal portion of the AZM extends posteriorly in a groove 30–44 7mu; (average = 36.8 μ) on the right side of the body. Dorsally are eight rows of stiff cilia. The details of the silverline system are similar to those of D. scutum .
There is insufficient difference in ranges of body length, width. and buccal cavity length to use these characters in separating the two species. However, a statistical analysis shows that the length of the portion of the AZM on the right side of the body in D. scutum is significantly different (longer) from that of D. peloetes. Furthermore, these two species differ not only in number of dorsal ciliary rows, but also in the number of cilia per row. The degree of difference in these two species is similar to that between closely related species in other hypotrich genera, and also to that between some varieties of Paramecium aurelia.  相似文献   

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A survey was conducted to study the morphology of the sandfly fauna in South-Western Pakistan (Balochistan). During the revision of different genera of sandflies the specimens of Phlebotomus papatasi (Scopoli) (N = 720), Ph. bergeroti Parrot (N = 30) and Ph. salehi Mesghali (N = 70) were encountered in various localities. These localities appear to be new records of the subgenus in the literature to date. Ph. bergeroti is reported for the first time from Pakistan and Ph. salehi from Balochistan as well. Characters of these three Pakistanese Phlebotomus are compared with the published data of these species from other countries. Keys for the identification of Pakistanese Phlebotomus are also constructed. Two female Ph. papatasi collected from indoors out of 132 female flies (1.5%) were found positive with flagellate infection in pharynx and midgut. The possible vectorial role of these flies is also discussed. Further surveys are necessary in parts of the country that have not been systematically surveyed.  相似文献   

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