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1.
The genus Symbiodinium is the commonly observed symbiotic dinoflagellate (zooxanthellae) that forms mutual associations with various marine invertebrates. Numerous studies have revealed that the genus is comprised of a group of diverse taxa, and information on the phylogenetic relationships among the genus’ members is increasing. In this study, small subunit (SSU) ribosomal RNA (ssrRNA) gene sequences were determined for 15 more Symbiodinium strains from 12 relatively unstudied host taxa (Indo-Pacific tridacnids, cardiids, sponge, and soft coral), 1 hitherto unreported free-living Symbiodinium strain, and 4 other Symbiodinium strains from four other host taxa (Indo-Pacific zoanthid, foraminifer, jellyfish, and mid-Pacific hard coral). Their respective phylogenetic positions were inferred, and strains that are either closely related to or distinct from previously reported Symbiodinium taxa were revealed. The cultured Symbiodinium strains isolated from individuals of six species of tridacnids and three species of cardiids all had identical ssrRNA gene sequences, are closely related to S. microadriaticum Freudenthal, and are indistinguishable from the RFLP Type A strain previously reported. However, the ssrRNA gene sequences of clam symbionts that were obtained via gene cloning were different from those of the cultured isolates and represent strains that are close to the RFLP Type C strains. The Symbiodinium-like dinoflagellate from the Indo-Pacific sponge Haliclona koremella De Laubenfels is distinct from any of the Symbiodinium taxa studied and may be similar to the symbiont previously isolated from the stony coral Montipora patula Quelch. The isolates from the soft coral Sarcophyton glaucum Quoy et Gaimard and from the zoanthid Zoanthus sp. are both very closely related to S. pilosum Trench et Blank. The free-living Symbiodinium isolate is very closely related to the symbiont isolated from the Indo-Pacific foraminifer Amphisorus hemprichii Ehrenberg, which in turn is distinct from the Red Sea strain isolated from a similar host. Theisolate from Cassiopeia sp. is different from S. microadriaticum F., the type species harbored by Cassiopeia xamachana Bigelow, and is instead very closely related to S. pulchrorum Trench isolated from a sea anemone. The symbiont from the stony coral M. verrucosa Lamarck is a sister taxon to the symbionts isolated from the foraminifera Marginopora kudakajimensis Gudmundsson and Sorites orbiculus Forskål. These data suggest that polymorphic symbioses extend from cnidarians to some bivalve, foraminifer, and jellyfish host species.  相似文献   

2.
S Kubota  K Ikeda  J T Yang 《Biopolymers》1983,22(10):2237-2252
A series of sequential polypeptides (LysiRj)n (R is Leu, Ser, or Gly) and random copolypeptides, (Lysx, Leuy)n, were synthesized. Their conformation in NaDodSO4 solution was determined by CD. Only (Lys-Leu)n, (Lys-Ser)n, and (Lys3-Ser)n adopt a stable β-form in the surfactant solution; (Lys-Ser2)n, (Lys-Ser3)n, (Lys2-Ser2)n, and (Lys2-Ser)n have an unstable β-form, which reverts to an unordered form in high NaDodSO4 concentrations, even though both Ser and DodSO-bound Lys+ are β-formers. In contrast, (Lys-Gly)n remains unordered in NaDodSO4 solution. On the other hand, Lys-rich (Lys2-Leu)n forms an unstable helix and (Lys2-Leu2)n a stable helix in NaDodSO4 solution. In 25 mM NaDodSO4 (Lysx, Leuy)n also forms a helix up to x = 75 and reverts to the β-form at x = 90. This compares with the helical conformation of (Lysx, Alay)n up to x = 65 and its β-form at x = 90, suggesting that Leu is an even stronger helix-former than Ala. Our results may provide a plausible explanation for the increase in helicity and disruption of the β-form for many proteins in NaDodSO4 solution, that is, the polypeptide chain of a protein usually favors a helical conformation over a β-form in the presence of excess surfactant.  相似文献   

3.
The formation of sperm cells has been examined ultrastructurally in the tricellular pollen grains ofGalium mollugo L. (Rubiaceae).Trichodiadema setuliferum Schwantes (Aizoaceae), andAvena sativa L. (Poaceae). After detachement from the intine the generative cell of all three species lies free within the vegetative cytoplasm. The two sperm cells are built inTrichodiadema andAvena by a single separating wall, while inGalium mollugo two independent walls are formed. However, both mechanisms separate the two male gametes completely.  相似文献   

4.
Summary The location and nucleotide sequence of tobacco chloroplast genes for tRNASer (GGA), tRNAThr (UGU), tRNALeu (UAA) and tRNAPhe (GAA) (trnS-GGA, trnT-UGU, trnL-UAA and trnF-GAA, respectively) have been determined. These genes are located in the 10 kbp BamHI fragment which lies in the middle of the large single-copy region of the chloroplast DNA. The gene order is trnS-trnT-trnL-trnF. The trnS, trnL and trnF are encoded on the same strand while the trnT on the opposite strand. The trnL contains a 503 bp intron like maize and broad bean trnL-UAAs.  相似文献   

5.
Summary The location and nucleotide sequences of tobacco chloroplast genes for tRNAIle (CAU), tRNALeu (CAA), tRNACys (GCA), tRNASer (UGA) and tRNAThr (GGU) (trnI-CAU, trnL-CAA, trnC-GCA, trnS-UGA and trnT-GGU, respectively) have been determined. The trnI and trnL are located in the inverted repeat region. The trnC, trnS and trnT are present in the large single copy region. These five tRNA genes together with the 25 different tRNA genes previously published have been compiled and compared. These 30 tRNA genes corresponding to 20 amino acids are most likely to be all of the tRNA genes encoded in tobacco chloroplast genome.This paper is dedicated to Professor Morio Ikehara on the occasion of his retirement from Osaka University in March 1986.  相似文献   

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8.
The comparative study of the karyotypes of Microcebus (Lemur, Cheirogaleid) and Cebus (Platyrrhini, Ceboid) shows important similarities between nearly all large chromosomes of these two genera. Since a relationship has been previously found between the Karyotypes of Homo and Cebus, a correspondence may be found between many chromosomes of man and those of Lemurs. This study enlarges the filed of comparative cytogenetics at the level of the primate order.  相似文献   

9.
Abstract The karyomorphology of three species in Dipentodon (Dipentodontaceae), Perrottetia (Celastraceae), and Tapiscia (Tapisciaceae), namely Dipentodon sinicus, Perrottetia racemosa, and Tapiscia sinensis, was investigated in the present study. Recent molecular research has discovered close relationships among these three genera, which has led to the establishment of the order Huerteales with Perrottetia being placed in Dipentodontaceae. Herein we report the chromosome numbers of D. sinicus and P. racemosa for the first time, and present their karyotype formulas as 2n= 34 = 22 sm + 12 st (D. sinicus), 2n= 20 = 11 m + 9 sm (P. racemosa), and 2n= 30 = 22 m(2SAT) + 8sm (T. sinensis). Asymmetry of their karyotypes is categorized to be Type 3B in D. sinicus, Type 2A in P. racemosa, and Type 2A in T. sinensis. Each of the species shows special cytological features. Compared with Perrottetia, Dipentodon has a different basic chromosome number, a higher karyotype asymmetry, and different karyomorphology of its interphase nuclei, mitotic prophase, and metaphase. Thus, on the basis of these results, we have reservations regarding the suggestion of placing Dipentodon and Perrottetia together in the family Dipentodontaceae.  相似文献   

10.
The helix–coil transitions of poly(Nε-methyl, Nε-carbobenzoxy-L -lysine), poly(Nδ-methyl, Nδ-carbobenzoxy-L -ornithine), and poly(Nδ-ethyl, Nδ-carbobenzoxy-L -ornithine) in chloroform–dichloroacetic acid and their corresponding decarbobenzoxylated polypeptides in alkaline solutions were followed by optical rotation measurements. The introduction of a methyl or an ethyl group to the side chains of the carbobenzoxy derivatives of poly(L -lysine) and poly(L -ornithine) appeared to weaken the helical conformation at 25°C. The thermodynamic quantities of the three water-soluble polypeptides were calculated from the data on potentiometric titrations at several temperatures. For uncharged coil-to-helix transition, ΔH = ?370 cal/mol and ΔS = ?1.1 eu/mol for poly(Nε-methyl-L -lysine), and ΔH = ?540 cal/mol and ΔS = ?1.6 eu/mol for poly(Nδ-ethyl-L -ornithine) (all on molar residue basis). The absolute values of ΔH and ΔS dropped in the region of pH-induced transition and eventually both quantities became positive. The initiation factor σ was about 2 × 10?3, which was essentially independent of temperature. For poly(Nδ-methyl-L -ornithine) the coil-to-helix transition was not complete even when the polymer was uncharged at high pH.  相似文献   

11.
Some properties of salivary amylases of the adults of Adelphocoris suturalis Jakovlev and Dolycoris baccarum L. were studied in vitro and compared with those of several other heteropteran species. The reducing sugar produced by the action of the salivary amylase of D. baccarum increased in proportion to substrate concentration while the concentration was relatively low (below 0.67% in its final concentration). Its increase stopped at the concentrations from 0.67 to 2.0%, and then it increased again constantly but slowly. The optimum temperature for the action of the enzyme was found to be about 50° (in A. suturalis) and about 40° (in D. baccarum), and the optimal pH was 3.5–4.0 in A. suturalis and 6.0 in D. baccarum. The salivary amylase activity of D. baccarum was scarcely affected by NaCl, KNO3, and other compounds, while the salivary amylase of A. suturalis was strongly activated by NaCl and moderately by KNO3. It seems highly probable that taxonomically related heteropterous insects might well be grouped with respect to the degree of activation of the salivary amylase by Cl- or NO3-.
Zusammenfassung Einige Eigenschaften der Speichelamylase von Adelphocoris suturalis und Dolycoris baccarum wurden im Reagenzglas studiert und mit denen anderer Heteropterenarten verglichen. Die durch die Wirkung der Speichelamylase von D. baccarum produzierten Stärkehydrolysate vermehrten sich im Verhältnis zur Substratkonzentration bei einer verhältnismäßig niedrigen Konzentration (weniger als 0,67% in der Schlußkonzentration). Diese Vermehrung wurde bei einer Konzentration von etwa 0,67 bis 2,0 unterbrochen, um sich dann wieder stetig, aber langsamer fortzusetzen. Die optimale Temperatur für die Wirkung des Fermentes lag für A. suturalis bei etwa 50° und für D. baccarum bei etwa 40°. Die optimale Wasserstoff-Ionenkonzentration betrug für A. suturalis pH 3,5–4,0 und für D. baccarum pH 6,0. Die Aktivität der Speichelamylase von D. baccarum wurde durch NaCl, KNO3 und andere Verbindungen kaum beeinflußt, während die Speichelamylase von A. suturalis durch NaCl stark und durch KNO3 schwach aktiviert wurde. Es wird vermutet, daß, hinsichtlich des Aktivierungsgrades der Speichelamylase durch Cl- und NO3-, systematisch nahe verwandte Heteropterenarten der gleichen Gruppe angehören.


Contribution No. 28 from the Laboratory of Entomology, Obihiro Zootechnical University.  相似文献   

12.
The synthesis and characterization of cloxacillin (clox) complexes with divalent metal ions [Co (II), Cu (II), Ni (II) and Zn (II)] is described. The nature of bonding of the chelated cloxacillin and the structures of the metal complexes have been elucidated on the basis of their physical and spectroscopic data. In all the complexes, the cloxacillin acts as a uninegatively charged bidentate ligand with coordination involving the carboxylate-O and endocyclic-N of the β-lactam ring. The new compounds have been screened for in-vitro antibacterial activity against Escherichia coli (a), Klebsiella pneumonae (b), Proteus mirabilis (c), Pseudomonas aeruginosa (d), Salmonella typhi (e), Shigella dysentriae (f), Bacillus cereus (g), Corynebacterium diphtheriae (h), Staphylococcus aureus (j) and Streptococcus pyogenes (k) bacterial strains. The brine shrimp bioassay was also carried out to study their in-vitro cytotoxic properties. All compounds, respectively, showed a promising activity (90%) against five bacterial species at 10 μg/ml concentration and a significant activity (52%) against the same test bacteria at 25 μg/ml concentration.  相似文献   

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Actinobacterial diversity was investigated in three hot springs [Tengchong Frog Mouth (TFM) hot spring (in Tengchong, China), Kamchatka Robb Flag hot spring (in Kamchatka, Russia), and Nevada Boiling Spring (in Nevada, USA)], a Tengchong Frog Mouth hot spring-derived pond and a soil sample near the TFM hot spring. Culture-independent techniques were employed including denaturing gradient gel electrophoresis and actinobacterial 16S rRNA gene phylogenetic analysis. The three hot springs and the hot spring-derived pond had pH of 6.8 to 7.9 and temperature of 50 to 81°C. Actinobacteria were for the first time found to be very diverse in hot springs with temperature up to 81°C, indicating that they have an unexpected capability of adapting to hot spring environments. A total of 346 actinobacterial clones were obtained from the three hot springs, and these clones were identified as 31 RFLP types, falling into the Actinomycetales (only limit to the Frankineae suborder), the Rubrobacterales, uncultured Candidatus Microthrix, unclassified Actinobacteria, and uncultured Candidate Division OP10. Our data have implications for a better understanding of the distribution of Actinobacteria in hot springs.  相似文献   

15.
The genes for three convertases, PC1 (Nec-1), PC2 (Nec-2), and furin (Fur), have been regionally localized on chromosomes 13, 2, and 7, respectively, by interspecific backcross analysis. These results refine previous localizations by in situ hybridization as well as confirm and extend known regions of homology between mouse and human chromosomes.  相似文献   

16.
We have examined the linkage relationships between five biochemical markers, Acon-1, Ahd-2, Ahd-c, Akp-1, and Hao-1, and 19 other genetic loci in five breeding combinations. The genetic locus that codes for a recently described aldehyde dehydrogenase in the liver (Ahd-c) has been assigned to linkage group X (LG X). Hydroxyacid oxidase is coded for by a locus (Hao-1) that is linked to genes that encode agouti coat color and seminal vesicle proteins in linkage group IV. Alkaline phosphatase (Akp-1) was linked to the locus that encodes the C6 component of complement and this association provisionally defines a new linkage group (LG XI) in the rat. The locus Acon-1 could not be positively assigned to a specific linkage group but the results from one breeding combination suggest that this locus may be included in linkage group II. No linkage relationship could be detected for the aldehyde dehydrogenase coded for by Ahd-2.This work was supported by Grant GM 32580 from the National Institutes of Health, United States Public Health Service.  相似文献   

17.
The gastrointestinal morphology was investigated in three mammalian insectivorous species, namely Acomys spinosissimus, Crocidura cyanea, and Amblysomus hottentotus. The aim of the study was to provide a comprehensive morphological comparison between the different species and to explore whether anatomical gastrointestinal adaptations are associated with the insectivorous diet of these species. The shape, proportional length, and proportional surface areas of the different gastrointestinal regions were recorded and compared in the three insectivores. Hematoxylin and Eosin (H&E) and Alcian Blue/Periodic Acid Schiff (AB/PAS) were used for morphological assessment. In all three species, the stomach was simple and uncompartmentalized. The internal aspect of the stomach in A. spinosissimus was hemi‐glandular, containing stratified squamous epithelium in the fundus, with glandular epithelium in the body and pyloric region. However, C. cyanea and A. hottentotus had wholly glandular stomachs. Paneth cells were not observed in the intestinal tracts of C. cyanea and A. hottentotus. Acomys spinosissimus was the only species studied that had a cecum. The proximal colonic region of A. spinosissimus had V‐shaped mucosal folds. Histologically, C. cyanea had villi throughout the entire gastrointestinal tract (GIT), whereas for A. hottentotus villi were not present in the most distal gastrointestinal regions. In both C. cyanea and A. hottentotus, longitudinal mucosal folds were present in the distal part of the colon. The GITs of C. cyanea and A. hottentotus showed little morphological differentiation namely, a simple, glandular stomach and the lack of a cecum. J. Morphol., 2013. © 2013 Wiley Periodicals, Inc.  相似文献   

18.
Antibacterial Schiff bases derived from 1,2,4-triazoles as well as their metal complexes incorporating cobalt(II), nickel(II), copper(II) and zinc(II) have been synthesized and characterized. Physico-chemical studies suggest that an octahedral geometry for the cobalt(II), nickel(II) and zinc(II)and square-planer geometry for the copper(II) complexes. These complexes have been screened for antibacterial activity against three Gram-positive (Staphylococcus aureus, Staphylococcus epidermidis and Bacillus subtilis) and two Gram-negative (Salmonella typhi and Pseudomonas aeruginosa) bacterial strains, and results compared with the activity of the free ligands. The metal complexes were found to be more potent against one or more bacterial strains than the free ligands.  相似文献   

19.
Traditionally, Tinospora cordifolia (Willd.) Hook. F. & Thomson (Menispermaceae), Ocimum sanctum L. (Lamiaceae), Moringa oleifera Lam. (Moringaceae), and Phyllanthus niruri L. (Euphorbiaceae) are some of the commonly used medicinal plants in India for curing ailments ranging from common cold, skin diseases, and dental infections to major disorders like diabetes, hypertension, jaundice, rheumatism, etc. To understand and correlate their medicinal use, trace element studies on the aqueous extract of these medicinal plants have been carried out using particle-induced X-ray emission technique. A 2-MeV proton beam was used to identify and characterize major and minor elements namely Cl, K, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Br, and Sr in them. Results have revealed that these elements are present in varying concentrations in the selected plants. Notable results include very high concentrations of Cl, K, and Ca in all the leaf samples, appreciable levels of Mn in all plants, high Zn content in T. cordifolia, and the aqueous extract of Moringa leaves compared to others and relative higher concentrations of Cr in all the plants.  相似文献   

20.
A 13C-nmr study of the salt-induced helix–coil transition of the basic polypeptides poly(L -lysine) [(Lys)n], poly(L -arginine) [(Arg)n], and poly (L -ornithine) [(Orn)n] was performed to serve as a reference of the helical portion of histones and other proteins. As is the case with pH-induced helix–coil transition, the downfield displacement of the Cα and carbonyl carbon signals are observed in the helical state. The upfield shift of the Cβ signals, on the other hand, is noted in the salt-induced transition. Regardless of the differences in the side chains and also the salts used, very similar helix-induced chemical shifts are obtained for (Lys)n and (Arg)n. However, the displacement of the Cα, Cβ, and carbonyl carbons of (Orn)n in the presence of 4M NaClO4 is found to be almost 50% of that of (Lys)n and (Arg)n. This is explained by the fact that the maximum helical content is about 50%, consistent with the ORD result. Further, the motion of the backbone and side chains of the helical from was estimated by measuring the spin-lattice relaxation time (T1), nuclear Overhauser enhancement (NOE), and line width. In the case of (Lys)n, the motion of the side chains is charged very little in comparison with that of the random coil. Indicating that the aggregation of the salt-induced helix is small in contrast to that of the pH-induced helix. For (Arg)n, however, the precipitate of the helical polymers is mainly due to aggregation.  相似文献   

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