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A bacterial strain AM7, isolated from soil and identified as Bacillus circulans, produced two kinds of novel cyclic oligosaccharides. The cyclic oligosaccharides were produced from amylose using a culture supernatant of the strain as the enzyme preparation. The major product was a cyclomaltopentaose cyclized by an alpha-(1-->6)-linkage, cyclo-{-->6)-alpha-D-Glcp-(1-->4)-alpha-D-Glcp-(1-->4)-alpha-D-Glcp-(1-->4)-alpha-D-Glcp-(1-->4)-alpha-D-Glcp-(1-->}. The other minor product was cyclomaltohexaose cyclized by an alpha-(1-->6)-linkage, cyclo-{-->6)-alpha-D-Glcp-(1-->4)-alpha-D-Glcp-(1-->4)-alpha-D-Glcp-(1-->4)-alpha-D-Glcp-(1-->4)-alpha-D-Glcp-(1-->4)-alpha-D-Glcp-(1-->}. We propose the names isocyclomaltopentaose (ICG5) and isocyclomaltohexaose (ICG6) for these novel cyclic maltooligosaccharides having one alpha-(1-->6)-linkage. ICG5 was digested by alpha-amylase derived from Aspergillus oryzae, cyclomaltodextrin glucanotransferase (CGTase) from Bacillus stearothermophilus, and maltogenic alpha-amylase. On the other hand, ICG6 was digested by CGTase from B. stearothermophilus and B. circulans, and maltogenic alpha-amylase. This is the first report of enzymatically produced cyclomaltopentaose and cyclomaltohexaose, which have an alpha-(1-->6)-linkage in their molecules.  相似文献   

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A structural characterization of bound water molecules in the cyclic tetrasaccharide, cyclo-{-->6}-alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->6)-alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->), was carried out by NMR spectroscopy. H-1', 2'-OH, H-3', and 4'-OH of the 3-O-glycosylated residue and H-1 of the 6-O-glycosylated residue were found to cross-relax with protons of bound waters using the double-pulsed field-gradient spin-echo ROESY experiment. In the crystal structure, one water molecule is located in the center of the plate, and its temperature factor is very low, indicating that this water molecule is an intrinsic component.  相似文献   

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Observations and telemetry-surveys of feral Camargue coypus showed dusk- and night-activity. Start and end of activity were correlated with sunset and sunrise respectively but influenced by climate and animals' individual history. A comparison with captive coypus in Britain showed differences caused by the stable social and abiotic environment, food-quality and proximity of feeding- and resting-places in the cage. Resting in close body-contact — frequent in a stable environment — occurred very seldom in Camargue coypus. In this species, two behaviours of the two-oscillator-model for activity-control could occur in different activities.  相似文献   

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Wu Z  Kong F 《Carbohydrate research》2004,339(17):2761-2768
Hexaose, beta-D-Glcp-(1-->3)-[beta-D-Glcp-(1-->6)]-alpha-D-Glcp-(1-->3)-beta-D-Glcp-(1-->3)-[beta-D-Glcp-(1-->6)]-beta-D-Glcp, based dimers were synthesized by twofold glycosidation of the hexaosyl trichloroacetimidate with hexylene 1,6-diol, diethylene glycol and triethylene glycol, respectively. Meanwhile, a triose, beta-1D-Glcp-(1-->3)-[beta-D-Glcp-(1-->6)]-beta-D-Glcp, based trimer was obtained by glycosidation of the triosyl trichloroacetimidate with a glycerol-derived triol scaffold.  相似文献   

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Siderocelis irregularis Hindák, representing a genus Siderocelis (Naumann) Fott that is known from European temperate waters, was identified as a common phytoplankter in Lake Tanganyika. It was found aposymbiotic as well as ingested (possibly endosymbiotic) in lake heterotrophs, mainly Strombidium sp. and Vorticella spp. The morphology and ultrastructure of the species, studied with LM, SEM and TEM, are described with emphasis on the structure of the cell wall and the pyrenoid. Presented at the International Symposium Biology and Taxonomy of Green Algae V, Smolenice, June 26–29, 2007, Slovakia.  相似文献   

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Ooencyrtus nezarae (Hymenoptera: Encyrtidae) is an egg parasitoid of bean bug Riptortus pedestris (Hemiptera: Alydidae) which is a major pest of beans. Females of O. nezarae are attracted to (E)‐2‐hexenyl (Z)‐3‐hexenoate (EZ), one of the components of aggregation pheromone of Rpedestris. Effects of three isomers (ZE, EE and ZZ) of EZ on the attractiveness of O. nezarae were tested using electroantennography (EAG) and field bioassays. EAG analyses revealed that the response of O. nezarae to ZE was significantly higher than those to air, hexane and two other isomers, even though the response was lower than that to EZ. ZE affected the attractiveness of EZ dose‐dependently in the field. Addition of ZE (100 mg) to EZ (10 mg) caused a significant reduction in the catches of O. nezarae females. Single or binary addition of two other isomers (EE and ZZ) to EZ could not decrease or increase significantly the number of O. nezarae catches of EZ. Even though addition of ZZ (10, 50 or 100 mg) to EZ (10 mg) caused dose‐dependent reduction in the number of O. nezarae female catches, the reductions were not significantly different from that of EZ. EZ and its three isomers were not attractive to O. nezarae males at all.  相似文献   

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A new case of a Robertsonian translocation diagnosed in an infertile bitch of West Highland White Terrier breed is reported. Cytogenetic analyses were performed with the use of Giemsa staining, Q-, C- and Ag-I banding techniques and FISH with canine whole X chromosome paint. The karyotype of this bitch was described as 77,XX der (8;14)(q10;q10).  相似文献   

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Wu Z  Kong F 《Carbohydrate research》2003,338(17):1727-1735
alpha-D-Manp-(1-->3)-[alpha-D-Manp-(1-->6)]-alpha-D-Glcp-(1-->3)-beta-D-Glcp-(1-->3)-[alpha-D-Manp-(1-->6)]-D-Glcp and alpha-D-Manp-(1-->3)-[beta-D-Glcp-(1-->6)]-alpha-D-Glcp-(1-->3)-beta-D-Glcp-(1-->3)[-alpha-D-Manp-(1-->6)]-D-Glcp were synthesized in a regio- and stereoselective way as the mannose-containing analogues of the immunomodulating beta-D-Glcp-(1-->3)-[beta-D-Glcp-(1-->6)]-alpha-D-Glcp-(1-->3)-beta-D-Glcp-(1-->3)-[beta-D-Glcp-(1-->6)]-D-Glcp.  相似文献   

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(Subject & verb)     
Sara Ann Greenslit 《CMAJ》2010,182(16):E754
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Renewed examinatinon with improved banding techniques of a boy previously reported to have the karyotype 46, XY,del(12)(p11) revealed a translocation 46, XY,t(10;12)(p13;p11), and reexamination of a boy previously reported to have the karyotype 46,XY/46,XY,del(5)(p13) showed the same mosaicism, but with a significantly lower frequency of cells with del(5)(p13), 8% compared with 23% at the time of birth. The decrease of the frequency of cells with chromosome abnormality in mixoploids during the first years of life as found in the present case as well as in prevously reported cases is discussed.  相似文献   

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Predation has important ecological and evolutionary consequences. Evolutionary responses to diversifying selection include genetic differentiation, the evolution of adaptive phenotypic plasticity, and the genetic differentiation of plastic responses between populations. We tested if pumpkinseed sunfish ( Lepomis gibbosus ) respond to predation cues by changing their external body form in functionally sensible ways. We then asked whether predation has influenced the divergence of coexisting littoral and pelagic ecomorphs, by testing for divergent predator-induced responses. Juvenile L. gibbosus of both ecomorphs were reared with and without predation cues supplied by walleye ( Sander vitreus ) feeding on L. gibbosus . Predation cues stimulated increased body depth and dorsal spine length, but no increase in anal spine length or pectoral fin size. The dorsal spines of pelagic ecomorphs also grew longer than did those of littoral ecomorphs, while positive body depth responses were similar in both ecomorphs. This is the second fish taxa in which predator-induced morphological responses have been found, and the first in which divergent responses have been detected between ecomorphs. This suggests that the developmental systems of L. gibbosus ecomorphs have diverged under selection related to predation. We propose that other 'resource polymorphisms' in fishes have evolved under selection arising from a variety of factors, including predation, and not just selection related to resource use.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 90 , 25–36.  相似文献   

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Summary The karyotype of Ateles geoffroyi (Cebidae; Primates; Mammalia) was studied using G- and C-banding techniques, and standardized idiograms are proposed. A polymorphism of chromosome 3 due to a pericentric inversion has been identified for the first time. Genetic analysis of this polymorphism showed Mendelian inheritance.  相似文献   

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Abstract: Generally, lycophytes are not well represented in Anisian floras. Nonetheless, four different genera, each with one species, have been distinguished in the Anisian flora from Kühwiesenkopf (Monte Prà della Vacca), Italy. They were well preserved and yielded leaf cuticles in all four taxa and in situ spores in two of them. Lycopia dezanchei gen. et sp. nov. is the most common form; it is characterized by a dichotomising creeping prostrate rhizome (representing the primary shoot axis) from which arise aerial axes, apically bifurcated and covered with bundles of long leaves. This taxon cannot be attributed to any of the lycophyte orders, but most resembles Lycopodiales. Two representatives of the Isoetales have been found, of which Isoetites brandneri sp. nov. is abundant. This species is characterized by a short stem, which is unusual for this genus. In situ immature microspores and megaspores were found in some specimens. Lepacyclotes bechstaedtii sp. nov. has a quadrilobe corm with fertile scales inserted in whorls or slightly helicoidally. Short sterile leaves arise distally from the corm in some specimens. Selaginellales are very rare in the flora; Selaginellites leonardii sp. nov. is represented by a strobilus that yielded both micro‐ and megaspores. Some sterile fragments have been found associated, but never in organic connection.  相似文献   

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