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1.
Globoseries glycosphingolipids of human meconium   总被引:2,自引:0,他引:2  
Globoside and an extended globoseries glycosphingolipid with a blood group H determinant were isolated from pooled human meconia and structurally characterized by mass spectrometry, proton NMR spectroscopy, and degradational techniques using GC and GC-MS analyses. Both species contained mainly phytosphingosine and hydroxy fatty acids characteristic for human intestinal epithelial cells. With the same techniques also minor amounts of globoside with sphingosine and nonhydroxy fatty acids and a novel globoseries tetraglycosyl ceramide with a terminal N-acetylglucosamine were isolated and structurally characterized.  相似文献   

2.
The glycoasparagines in urine of a patient with aspartylglycosaminuria   总被引:1,自引:0,他引:1  
The isolation and analysis of 2-acetamido-N-(4'-l-aspartyl)-2-deoxy-beta-d- glucopyranosylamine and 13 higher-molecular-weight derivatives from the urine of a patient with aspartylglycosaminuria is described. Some structural information is presented for nine of these compounds.  相似文献   

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Ammonoids had high evolutionary rates and diversity throughout their entire history and played an important role in the high‐resolution sub‐division of the Mesozoic, but much of their palaeobiology remains unclear, including the brooding habitat. We present our study of the first recorded ammonite embryonic shell clusters preserved with calcified embryonic aptychi in situ within the body chambers of mature macroconch shells of the Early Aptian (Early Cretaceous) ammonite Sinzovia sazonovae. The following support the idea that the clusters are egg masses, which developed inside ammonite body chambers: the absence of post‐embryonic shells and any other fossils in these clusters, the presence of the aptychi in all embryonic shell apertures and peculiarities of adult shells preservation. These facts confirm earlier speculations that at least some ammonoids could have been ovoviviparous and that, like many modern cephalopods, they could have reproduced in mass spawning events. The aptychi of ammonite embryonic shells are observed here for the first time, indicating that they were already formed and calcified before hatching. Our results are fully congruent with the peculiar modes of ammonoid evolution: quick recovery after extinctions, distinct evolutionary rates, pronounced sexual dimorphism and the nearly constant size of embryonic shells through ammonoid history. We assume that adaptation to ovoviviparity may be the reason for the presence of these features in all post‐Middle Devonian ammonoids.  相似文献   

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The first fossil remains of marmosets, an isolated incisor, premolar, and molar, all similar in size toCallithrix species, have been discovered in the middle Miocene La Venta fauna of Colombia. The M1 is referred to a new genus and species,Micodon kiotensis, characterized by a fully developed hypocone and low occlusal relief. The P4 and I1 resemble those ofCallithrix, suggesting a close affinity with callitrichin marmosets. In combining small size with a four-cusped morphology,Micodon demonstrates the shortcomings of typological definitions of platyrrhine families and suggests that small body size may have preceded the tricuspid molar pattern in marmoset evolution. The 14- to 15-Ma date for the La Venta suggests that marmosets are an at least moderately ancient radiation, contrary to estimates based upon the molecular clock.  相似文献   

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The acoustic ecology of marine fishes has traditionally focused on adults, while overlooking the early life-history stages. Here, we document the first acoustic recordings of pre-settlement stage grey snapper larvae (Lutjanus griseus). Through a combination of in situ and unprovoked laboratory recordings, we found that L. griseus larvae are acoustically active during the night, producing ‘knock’ and ‘growl’ sounds that are spectrally and temporally similar to those of adults. While the exact function and physiological mechanisms of sound production in fish larvae are unknown, we suggest that these sounds may enable snapper larvae to maintain group cohesion at night when visual cues are reduced.  相似文献   

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The oldest and most common parasite for which we have direct evidence, in the New World, is Enterobius vernicularis. Numerous archaeological sites, especially in the arid American southwest, have yielded fecal samples positive for pinworm ova, some of these dating back 10,000 yr. Reports of pinworm from the Old World are scarce. This article reports the first evidence of pinworm infection from Roman-occupied (30 BC-AD 395) Egypt.  相似文献   

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Antiserum directed against the alditol derivative of the human milk monosialyloligosaccharide sialyltetrasaccharide a [D. F. Smith, P. A. Prieto, and B. V. Torres (1985) Arch. Biochem. Biophys. 241, 298-303] is used to detect a new ganglioside in human meconium by direct binding on nitrocellulose filters of the sialyl[3H]oligosaccharide alditol obtained from gangliosides after ozonolysis and alkali fragmentation. The sialyl[3H]oligosaccharide is purified by affinity chromatography on a column containing anti-sialyltetrasaccharide a antibodies. The affinity-purified sialyl[3H]oligosaccharide cochromatographs with the 3H-labeled alditol derivative of authentic sialyltetrasaccharide a from human milk. Results of sequential enzyme degradation of the pure sialyl[3H]oligosaccharide and cochromatography of the digestion products with standards are consistent with the presence in meconium of a monosialylganglioside with the structure NeuAc alpha 2-3Gal beta 1-3GlcNAc beta 1-3Gal beta 1-4Glc-ceramide. This ganglioside is presumably the biosynthetic precursor of the sialyl-Lea ganglioside [G. C. Hansson and D. Zopf (1985) J. Biol. Chem. 260, 9388-9392], which is also a component of human meconium.  相似文献   

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Neutral reduced oligosaccharides are in general not sufficiently retained to achieve adequate separation and reproducible chromatography using high-pH anion-exchange chromatography. We describe a method to increase the retention using two columns in series. This method has been applied to the separation of oligosaccharides purified from human meconium glycoproteins, obtained as their alditols after alkaline-borohydride release of oligosaccharides. The neutral oligosaccharide alditols were significantly retained upon two CarboPac PA-100 columns, connected in series, and eluted in 80 mM sodium hydroxide between 4 and 10 min. Three sialylated alditols studied were substantially retained and could be eluted in a gradient of 0–500 mM sodium acetate—80 mM sodium hydroxide between 10 and 45 min. The elution patterns were based on their size, charge and linkage, such that oligosaccharide alditol isomers could be separated.  相似文献   

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The urinary excretion of fucose-containing material was found to be highly increased in a patient with fucosidosis type 2. Three structurally related compounds, a disaccharide and two glycoasparagines, were isolated from the urine. The isolation procedure included ultrafiltration, gel chromatography on Sephadex G-25, preparative zone electrophoresis and paper chromatography. From structural studies including optical rotation, sugar analysis, methylation analysis, ninhydrin degradation, reduction with lithium aluminium hydride and partial hydrolysis, the following structures were deduced: formula (see text), where Fucp is fucopyranose, Manp is mannopyranose, Galcp is galactopyranose, GlcNAcp is 2-acetamido-2-deoxyglucopyranose and Asn is asparagine. The yields of these compounds were 1.7, 40, and 6 mg/l, respectively. The origin of the disaccharide and the two glycoasparagines is probably the core region of glycoprotein carbohydrate chains.  相似文献   

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In the course of work on a systematic structural mapping of nonacid glycosphingolipids of human meconia, special attention was given to a major component preliminarily identified as an isomer of neolactotetraosylceramide (paragloboside). This component was isolated in its pure form from meconium of a blood group O individual and subjected to detailed structural analyses, using mass spectrometry and proton NMR spectroscopy on intact permethylated and permethylated-reduced (LiAlH4) derivatives, and gas liquid chromatography on degradational products of native, permethylated, and permethylated-reduced derivatives. The isolated compound was conclusively shown to have the structure Galp beta 1 yields 3GlcNAcp beta 1 yields 3Galp beta 1 yields 4Glcp beta 1 yields 1Cer, and is thus identified as lactotetraosylceramide. The major fatty acids were 2-hydroxy fatty acids with 16 and 20 to 24 carbon atoms, and the bases were sphingosine and phytosphingosine. This glycolipid, although not isolated and structurally characterized before, has long been thought of as a precursor substance of the Lewis active glycolipids and of ABH-active glycolipids with a type 1 saccharide chain.  相似文献   

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Flatz R  Gerber LR 《PloS one》2010,5(11):e13873
Demographic parameters such as birth and death rates determine the persistence of populations. Understanding the mechanisms that influence these rates is essential to developing effective management strategies. Alloparental behavior, or the care of non-filial young, has been documented in many species and has been shown to influence offspring survival. However, the role of alloparental behavior in maintaining population viability has not been previously studied. Here, we provide the first evidence for adoption in California sea lions and show that adoption potentially works to maintain a high survival rate of young and may ultimately contribute to population persistence. Alloparental behavior should have a positive effect on the population growth rate when the sum of the effects on fitness for the alloparent and beneficiary is positive.  相似文献   

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A prokaryotic protein, YtvA from Bacillus subtilis, was found to possess a light, oxygen, voltage (LOV) domain sharing high homology with the photoactive, flavin mononucleotide (FMN)-binding LOV domains of phototropins (phot), blue-light photoreceptors for phototropism in higher plants. Computer-based three-dimensional modeling suggests that YtvA-LOV binds FMN in a similar pocket as phot-LOVs. Recombinant YtvA indeed exhibits the same spectroscopical features and blue-light-induced photochemistry as phot-LOVs, with the reversible formation of a blue-shifted photoproduct, assigned to an FMN-cysteine thiol adduct (Thio383). By means of laser-flash photolysis and time-resolved optoacoustic experiments, we measured the quantum yield of formation for Thio383, Phi(Thio) = 0.49, and the enthalpy change, DeltaH(Thio) = 135 kJ/mol, with respect to the parent state. The formation of Thio383 is accompanied by a considerable volume contraction, DeltaV(Thio) = -13.5 ml/mol. Similar to phot-LOVs, Thio383 is formed from the decay of a red-shifted transient species, T650, within 2 micros. In both YtvA and free FMN, this transient has an enthalpy content of approximately 200 kJ/mol, and its formation is accompanied by a small contraction, DeltaV(T) approximately -1.5 ml/mol, supporting the assignment of T650 to the FMN triplet state, as suggested by spectroscopical evidences. These are the first studies indicating that phototropin-related, blue-light receptors may exist also in prokaryotes, besides constituting a steadily growing family in plants.  相似文献   

20.
Diatoms are considered the most successful and widespread group of photosynthetic eukaryotes. Their contribution to primary production is remarkably significant to the earth''s ecosystems. Diatoms are composed of two orders: Centrales and Pennales. Thus far, viruses infecting centric diatom species have been isolated and characterized; however, viruses infecting pennates have not been reported. Here, we describe the first isolations and preliminary characterizations of two distinct pennate diatom viruses, AglaRNAV (31 nm in diameter, accumulates in the host cytoplasm) and TnitDNAV (35 nm in diameter, accumulates in the host nuclei) infecting Asterionellopsis glacialis and Thalassionema nitzschioides, respectively. Their genomes contain a single-stranded RNA of approximately 9.5 kb, and a closed, circular single-stranded DNA of approximately 5.5 kb harboring a partially double-stranded region, respectively. Further analysis of these viruses may elucidate many aspects of diatom host–virus relationships.  相似文献   

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