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排序方式: 共有268条查询结果,搜索用时 31 毫秒
1.
L C Stephens D M Cromeens V W Robbins P C Stromberg J H Jardine 《Laboratory animal science》1987,37(3):341-344
Significant morbidity and mortality of South African clawed frogs, Xenopus laevis, can be caused by parasitism of the epidermis by a capillarid nematode. These worms produce an erosive dermatitis that is complicated by infection with gram-negative microorganisms. The nematode apparently has a direct life cycle that can be completed within the epidermis of the frog. These characteristics are suggested by the lack of an intermediate host and failure to detect visceral migration. Another unique feature of the parasite was the presence of larvated eggs, in utero. Some have named the parasite Capillaria xenopodis, whereas others called it Pseudocapillaroides xenopi to distinguish it form the typical members of the genus Capillaria. 相似文献
2.
Definition of the surface antigens of Mycobacterium malmoense and use in studying the etiology of a form of mycobacteriosis 总被引:2,自引:0,他引:2 下载免费PDF全文
M McNeil A Y Tsang J K McClatchy C Stewart I Jardine P J Brennan 《Journal of bacteriology》1987,169(7):3312-3320
Mycobacterium malmoense is the latest of a roster of atypical mycobacteria implicated in pulmonary infections. Yet it lacks recognizable phenotypic features to allow its ready identification. Some 23 clinical isolates of M. malmoense were examined for homologous seroagglutination reactions and characteristic surface antigens. One group showed concordant agglutination interreactions and an identical spectrum of glycolipids and are regarded as M. malmoense sensu stricto. The glycolipids are of the newly found, trehalose-containing lipooligosaccharide class. De-O-acylation followed by high-pressure liquid chromatography revealed one major and several minor oligosaccharides. Partial acidic cleavage to release glycosidically linked trehalose, alpha-mannosidase digestion to demonstrate the presence of a non-reducing-end mannobiose, perdeuteriomethylation, partial acid hydrolysis, reduction, and O ethylation, combined with 1H nuclear magnetic resonance and electron impact and fast-atom bombardment mass spectrometry revealed the structure of the major oligosaccharide as alpha-D-Manp-(1----3) -alpha-D-Manp-(1----[2-alpha-L-Rhap-(1--]4--3)-alpha-L-Rh ap- (1----3)-alpha-D-Glcp-(1----1)-alpha-D-Glcp, in which two of the 2-alpha-L-Rhap residues are O methylated at C-3. (Man, mannose; Rha, rhamnose; Glc, glucose; p, pyranosyl). The structures of the minor oligosaccharides were also determined; they differ at the distal nonreducing end. The dominant oligosaccharide was acylated by octanoate, 2-methyleicosanoate, and 2,4-dimethylpentacosanoate to yield the major species-specific surface antigen of M. malmoense, which we regard as the most characteristic feature of the pathogen. 相似文献
3.
Further novel amido sugars within the glycopeptidolipid antigens of Mycobacterium avium 总被引:3,自引:0,他引:3
C M Bozic M McNeil D Chatterjee I Jardine P J Brennan 《The Journal of biological chemistry》1988,263(29):14984-14991
The individual serovars of the Mycobacterium avium complex, a source of serious and persistent infections in individuals with underlying immune deficiencies, also present an extraordinary set of novel sugar epitopes as part of their type-specific glycopeptidolipid surface antigens. Californium desorption-mass spectrometry has been successfully applied to the holistic glycopeptidolipid antigen of M. avium serovar 12 and its per-O-acetyl derivative, to arrive at the following structure, of molecular mass 1876: (Sequence: see text). The pentasaccharide hapten, released as the tetraglycosyl alditol, was subjected to methylation analysis, absolute configurational analysis, 1H NMR and fast atom bombardment-mass spectrometry to arrive at the structure: 4-(2'-Hydroxy) propionamido-4,6-dideoxy-3-O-Me-Glcp (beta 1----3)-4-O-Me-L-Rhap (alpha 1----3)-L-Rhap (alpha 1----3)-L-Rhap (alpha 1----2)-6-deoxytalitol. Two-dimensional proton correlation spectroscopy was also applied to determine the configuration of the unique distal segment of the oligosaccharide unit. The significance of this structure in the context of the fully elucidated structures of the antigens from 12 of the 31-member M. avium complex is discussed. 相似文献
4.
A new peptide in the FMRFamide family isolated from the CNS of the hawkmoth, Manduca sexta 总被引:2,自引:0,他引:2
T G Kingan D B Teplow J M Phillips J P Riehm K R Rao J G Hildebrand U Homberg A E Kammer I Jardine P R Griffin 《Peptides》1990,11(4):849-856
We have purified a FMRFamide-like peptide from extracts of brain-subesophageal ganglion of the moth, Manduca sexta. The purification was monitored with a new, competitive ELISA, and accomplished with ion exchange and reverse-phase HPLC. The peptide structure was determined by a combination of tandem mass spectrometry and automated Edman degradation. The amino acid sequence of the peptide is less than Glu-Asp-Val-Val-His-Ser-Phe-Leu-Arg-Phe-amide (pEDVVHSFLRF-NH2). In a separate purification, an identical peptide was isolated from extracts of brain-associated neurohemal structures. We have named this peptide ManducaFLRFamide, to indicate its homology with other members of the "FMRFamide" family. In bioassays, chemically synthesized peptide increased the force of neurally evoked contractions in the major power-producing flight muscles, the dorsal longitudinal muscles. This observation suggests that hormonally released ManducaFLRFamide may play a role in sustaining or promoting the flight behavior necessary for mate-seeking (in males) or oviposition (in females) in sphingid moths. 相似文献
5.
We have broadly defined the DNA regions regulating esterase6 activity in
several life stages and tissue types of D. melanogaster using P-
element-mediated transformation of constructs that contain the esterase6
coding region and deletions or substitutions in 5' or 3' flanking DNA.
Hemolymph is a conserved ancestral site of EST6 activity in Drosophila and
the primary sequences regulating its activity lie between -171 and -25 bp
relative to the translation initiation site: deletion of these sequences
decrease activity approximately 20-fold. Hemolymph activity is also
modulated by four other DNA regions, three of which lie 5' and one of which
lies 3' of the coding region. Of these, two have positive and two have
negative effects, each of approximately twofold. Esterase6 activity is
present also in two male reproductive tract tissues; the ejaculatory bulb,
which is another ancestral activity site, and the ejaculatory duct, which
is a recently acquired site within the melanogaster species subgroup.
Activities in these tissues are at least in part independently regulated:
activity in the ejaculatory bulb is conferred by sequences between -273 and
-172 bp (threefold decrease when deleted), while activity in the
ejaculatory duct is conferred by more distal sequences between -844 and
-614 bp (fourfold decrease when deleted). The reproductive tract activity
is further modulated by two additional DNA regions, one in 5' DNA (-613 to
-284 bp; threefold decrease when deleted) and the other in 3' DNA (+1860 to
+2731 bp; threefold decrease when deleted) that probably overlaps the
adjacent esteraseP gene. Collating these data with previous studies
suggests that expression of EST6 in the ancestral sites is mainly regulated
by conserved proximal sequences while more variable distal sequences
regulate expression in the acquired ejaculatory duct site.
相似文献
6.
The RBEs of high-energy neutrons given in 9 or 12 fractions for cervical spinal cord injury in rhesus monkeys was determined using photons at 2.2 Gy per fraction as the reference radiation. Because the dose-response functions were not parallel, the RBE was not constant but rather increased with dose or, equivalently, with the probability of myelopathy. This required the development of a novel method of determining the RBE versus level of response. The RBE is presented as a function of probability of myelopathy from 0.1 to 99%. At a 50% incidence of myelopathy, the RBE (+/- 1 SE) was 5.22 +/- 0.15. A difference in the histopathology of lesions induced by photon and neutron treatments was observed. 相似文献
7.
Nucleotide variation at the hypervariable esterase 6 isozyme locus of Drosophila simulans 总被引:2,自引:0,他引:2
Esterase 6 (Est-6/EST6) is polymorphic in both Drosophila melanogaster and
D. simulans for two common allozyme forms, as well as for several other
less common variants. Parallel latitudinal clines in the frequencies of the
common EST6-F and EST6-S allozymes in these species have previously been
interpreted in terms of a shared amino acid polymorphism that distinguishes
the two variants and is subject to selection. Here we compare the sequences
of four D. simulans Est-6 isolates and show that overall estimates of
nucleotide heterozygosity in both coding and 5' flanking regions are more
than threefold higher than those obtained previously for this gene in D.
melanogaster. Nevertheless, the ratio of replacement to exon silent-site
polymorphism in D. simulans is less than the ratio of replacement to silent
divergence between D. simulans and D. melanogaster, which could be the
result of increased efficiency of selection against replacement
polymorphisms in D. simulans or to divergent selection between the two
species. We also find that the amino acid polymorphisms separating EST6- F
and EST6-S in D. simulans are not the same as those that separate these
allozymes in D. melanogaster, implying that the shared clines do not
reflect shared molecular targets for selection. All comparisons within and
between the two species reveal a remarkable paucity of variation in a
stretch of nearly 400 bp immediately 5' of the gene, indicative of strong
selective constraint to retain essential aspects of Est-6 promoter
function.
相似文献
8.
D S Jardine 《Journal of applied physiology》1992,73(1):329-339
A mathematical model was created to test the hypothesis that a partially covered febrile infant may develop potentially lethal temperature elevation. Infants may be at special risk to develop hyperthermia because, unlike older children, infants may not be able to remove blankets in response to temperature elevation. The model compared heat production (MTsk) with heat loss (Qtot). The difference between these terms is the excess energy (E): MTsk - Qtot = E. In most situations the simulated infant transfers heat to the environment as rapidly as it is produced (E less than 0), so hyperthermia does not result. In some situations, heat production exceeds heat loss (E greater than 0), causing progressive warming. The time was calculated for the simulated infant to progress from 41 to 43.4 degrees C (defined as a lethal end point). In certain circumstances, this may occur in less than 90 min. An infant at high risk of hyperthermia may not appear to be covered by a conspicuous excess of insulation (less than or equal to 3.5 cm may be sufficient). In many situations, heat loss is more closely determined by exposed body surface area than by blanket thickness. These findings have important implications for understanding the antecedents of hyperthermia in infants and may help in understanding the role of hyperthermia in certain pediatric illnesses. 相似文献
9.
Halvor Rollag Thor Ueland Anders ?sberg Anders Hartmann Alan G. Jardine Atul Humar Mark D. Pescovitz Angelo A. Bignamini P?l Aukrust 《PloS one》2013,8(4)
Background
While several studies have examined the general inflammatory responses in relation to cytomegalovirus infection, the identification of the various inflammatory mediators as well as their relative importance is far from clear.Patients and Methods
Solid organ recipients enrolled in an international multicenter trial of cytomegalovirus disease treatment (the VICTOR study) were analyzed (n = 289) (ClinicalTrials.gov ). Plasma markers of inflammation and endothelial cell activation were assessed at baseline by enzyme immunoassays. NCT00431353Results
The major findings were: (i) Plasma levels of the CXC-chemokine interferon-inducible protein-10 (P<0.001) and C-reactive protein (P = 0.046) were independently associated with the presence of cytomegalovirus DNAemia above lower level of quantification. (ii) High levels of CC-chemokine ligand 21 (P = 0.027) and pentraxin 3 (P = 0.033) were independently associated with tissue invasive cytomegalovirus disease as opposed to cytomegalovirus syndrome.Conclusion
Our findings illustrate the complex interaction between cytomegalovirus and the immune system, involving a wide range of inflammatory mediators that could be associated to disease manifestations in cytomegalovirus related disease. 相似文献10.
Cristina M. Jacobi Francisco Villamarín João V. Campos-Silva Timothy Jardine William E. Magnusson 《Journal of fish biology》2020,97(1):265-272
The giant arapaima (Arapaima sp.) has been described as a fish of change in Amazonia because of its important role in the conservation of floodplains, food security and income generation for rural communities. Nonetheless, despite the cultural, ecological and economic importance of arapaima, data on diet are scarce. Aiming to expand knowledge about arapaima diet in western Amazonia, scientific knowledge was integrated with the knowledge of local dwellers. During the low-water period (September 2018) and the falling-water period (June 2019), arapaima stomachs were collected from 11 floodplain lakes in the middle Juruá River. All fishes were measured [TL (total length)] and sexed. Food items from each stomach were categorized as fishes, invertebrates, plants and bone remains and weighed. Also, in the latter period, experienced local fishers were interviewed about arapaima feeding. This integrated approach revealed that young arapaima eat fish and invertebrates but adult arapaima eat fish of a wide range of species, which were mainly of low and intermediate trophic positions. This study reports the first case of cannibalism for arapaima and also shows that during the low-water period, many individuals had empty stomachs or only some small fish-bone remains and/or plant material. Arapaima sex and TL had no influence on the absence of prey in stomach contents. Overall, it can be concluded that local people had consistent ethnobiological knowledge of arapaima feeding ecology that could be useful within management projects in the region. 相似文献