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1.
We present a key to distinguish among the described tadpoles of Costa Rican frogs and toads, summarize the reproductive modes present in this group, and present a bibliography of the published illustrations of those tadpoles. 相似文献
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3.
Phylogenetic study of transcortin using monoclonal antibodies 总被引:1,自引:0,他引:1
We produced monoclonal antibodies that recognise three distinct epitopes of human transcortin. These epitopes are present on transcortin of humans with normal and altered transcortin levels, as well as on a variant with lower affinity for cortisol. One epitope is present on transcortin of Old World Monkeys and apes, the others are only present on transcortin of apes. The epitopes are not present on transcortin of other species. These results indicate that human transcortin contains a highly evolved and a more conserved part. 相似文献
4.
The chemistry of the collagen cross-links. The absence of reduction of dehydrolysinonorleucine and dehydrohydroxylysinonorleucine in vivo 总被引:3,自引:2,他引:1
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Two aldimine bonds have been shown to be present as stabilizing cross-links in intact collagen fibres from soft tissues: dehydrohydroxylysinonorleucine as a major component and dehydrolysinonorleucine being present in trace quantities. In the highly insoluble collagens less dehydrohydroxylysinonorleucine is present but the proportion of dehydrolysinonorleucine increases. In elastin the latter aldimine is reduced in vivo to give a more stable cross-link but no comparable reduction could be detected with either of the aldimines present in collagen. 相似文献
5.
pEG plasmid involved in styrene degradation: molecular dimorphism and integration of a segment into the chromosome 总被引:3,自引:0,他引:3
In the Pseudomonas fluorescens strain ST the ability to utilize styrene as the sole carbon source is due to the presence of a plasmid, pEG. In the present report we show that pEG contains two inverted repeat sequences and we present evidence indicating that the catabolic genes are localized in these repeats. The region separating the inverted repeats can assume alternative orientations. In the chromosome of strain ST, a 3 kbp region is homologous to sequences present at one end of the plasmid repeats. This region is present in one copy in the chromosome and could be a specific site for integration of the plasmid. We suggest that this sequence, which is present twice in the pEG plasmid and once in the chromosome, might be a transposon-like element. 相似文献
6.
C Grubben J P Fryns E Smeets H Van den Berghe 《Genetic counseling (Geneva, Switzerland)》1991,2(1):47-54
In this report we present a three-generation family in which five members present the basal cell nevus syndrome. In three of them a Noonan phenotype was present. The basal cell nervus syndrome is another example of a neural crest dysplasia associated with a Noonan-like phenotype. This observation supports the theory that the autosomal dominant mutation causing the neural crest dysplasia may lead to a Noonan-like phenotype. 相似文献
7.
Meng RX Janssen A Nomikou M Zhang QW Sabelis MW 《Experimental & applied acarology》2006,38(2-3):113-124
Predator diet is known to influence antipredator behaviour in prey. Yet, it is not clear how antipredator behaviour is affected
by diet changes of the predator. We studied the effect of previous and present diet of a predatory mite Typhlodromips swirskii on the antipredator response of its prey, the whitefly Bemisia tabaci. An earlier study showed that adult female whiteflies that had experienced predators, had learned to avoid ovipositing on
plants with predators whose previous and present diet consisted of whitefly eggs and immatures. Here, we investigate whether
adult whiteflies also avoid plants with predators whose present and/or previous diet consisted of a non-whitefly food source.
Adult whiteflies were found not to avoid plants with predators whose present diet consisted of pollen and whose previous diet
had consisted of either pollen or whitefly eggs and larvae. They did avoid plants with predators whose present diet consisted
of whiteflies and whose previous diet had consisted of pollen, but to a lesser extent than when previous and present diet
consisted of whiteflies. In a choice experiment, whiteflies discriminated between plants with predators whose present diet
consisted of whiteflies, but that differed in previous diet. Our results show that both previous and present diets of predators
are important in eliciting antipredator behaviour. 相似文献
8.
Mouse neuroblastoma cells grown in medium containing 10 percent fetal bovine serum have negligible amounts of glutathione peroxidase activity. Introduction of selenite to the medium to produce a concentration of 600 nM resulted in a 30-fold increase in the enzyme activity. This increase is directly proportional to the concentration below 60 nM and levels off at concentrations above this value. Selenate produces no increase in enzyme activity when present alone nor does it inhibit induction when present with selenite. Tellurite produces no increase in enzyme activity when present alone but does inhibit induction when present with selenite. 相似文献
9.
S B Field A C Upton 《International journal of radiation biology and related studies in physics, chemistry, and medicine》1985,48(1):81-94
The present recommendations of the ICRP (International Commission on Radiological Protection) are almost entirely based on 'stochastic effects' of ionizing radiation, i.e. cancer induction and heritable effects. In a recent report the compatibility of present recommendations with non-stochastic effects has been considered. The present paper is a summary of these findings. 相似文献
10.
Two new species of Eimeria were observed in the feces of captive white-tailed deer fawns, Odocoileus virginianus, from Alabama. The first new species was easily recognized because of its small size. Sporulated oocysts are spherical, average 10.2 by 10.0 microm, and lack a micropyle and oocyst residuum. Oocysts contain a polar granule and elongate-ellipsoidal sporocysts that measure 6.7 by 3.1 microm. A Stieda body is present on the sporocysts. Oocysts were observed in the feces, and gamonts and oocysts were observed in the jejunum of a month-old fawn from Minnesota that died from enteritis due to this species. Oocysts of this small species were present in 5 of the 6 white-tailed deer fawns examined. Oocysts of a second new species are ellipsoidal and average 29.5 by 24.6 microm. The oocyst encloses an oocyst residuum, polar granule, and elongate-ellipsoidal sporocysts that average 16.0 by 9.0 microm. A Stieda body and substieda body are present on the sporocysts. Oocysts of the second new species were present in 4 of the 6 white-tailed deer fawns examined. Oocysts of E. ivensae are ovoid or flask-like and average 32.0 by 20.8 microm. The oocyst wall is rough, contains a micropyle, and encloses elongate-ellipsoidal sporocysts that average 16.5 by 7.8 microm. A Stieda body is present on the sporocysts. Oocysts of E. ivensae were present in 4 of the 6 white-tailed deer fawns. Oocysts of E. odocoilei are spherical or slightly subspherical and measure 24.7 by 21.5 microm. They enclose ovoid sporocysts that average 12.7 by 8.8 microm. A Stieda and substieda body are present on the sporocyst. Oocysts of E. odocoilei were present in 4 of the 6 white-tailed deer fawns. 相似文献
11.
Adjustment of systematic microarray data biases 总被引:6,自引:0,他引:6
Benito M Parker J Du Q Wu J Xiang D Perou CM Marron JS 《Bioinformatics (Oxford, England)》2004,20(1):105-114
MOTIVATION: Systematic differences due to experimental features of microarray experiments are present in most large microarray data sets. Many different experimental features can cause biases including different sources of RNA, different production lots of microarrays or different microarray platforms. These systematic effects present a substantial hurdle to the analysis of microarray data. RESULTS: We present here a new method for the identification and adjustment of systematic biases that are present within microarray data sets. Our approach is based on modern statistical discrimination methods and is shown to be very effective in removing systematic biases present in a previously published breast tumor cDNA microarray data set. The new method of 'Distance Weighted Discrimination (DWD)' is shown to be better than Support Vector Machines and Singular Value Decomposition for the adjustment of systematic microarray effects. In addition, it is shown to be of general use as a tool for the discrimination of systematic problems present in microarray data sets, including the merging of two breast tumor data sets completed on different microarray platforms. AVAILABILITY: Matlab software to perform DWD can be retrieved from https://genome.unc.edu/pubsup/dwd/ 相似文献
12.
《Biochemical and biophysical research communications》1986,136(3):914-920
The phospholipid distribution across red cell membrane bilayer is asymmetrical. Sphingomyelin and phosphatidylcholine are predominantly present in the outer membrane bilayer, whereas only small amounts of phosphatidylethanolamine and no phosphatidylserine are present in the outer membrane bilayer. The present study, using specific phospholipase, chemical probe, and Russell's viper venom clotting time has found that in neonatal red cells a portion of PS is also present in the outer membrane bilayer. 相似文献
13.
We present a new technique for acquiring and analyzing intrinsic signal optical images of brain activity, using continuous stimulus presentation and data acquisition. The main idea is to present a temporally periodic stimulus and to analyze the component of the response at the stimulus frequency. Advantages of the new technique include the removal of heart, respiration, and vasomotor artifacts, a dramatic increase in spatial resolution, and a 30-fold or greater reduction in acquisition time. We also present a novel approach to localizing instantaneous neuronal responses using time-reversed stimuli that is widely applicable to brain imaging. To demonstrate the power of the technique, we present high-resolution retinotopic maps of five visual areas in mouse cortex and orientation maps in cat visual cortex. 相似文献
14.
The saccharogenic enzymes present in potato juice were studied. The actions were followed upon the substances present in the juice and upon added sucrose, maltose, and soluble starch. Sucrase and amylase were found to be present in the juice. No indication of a maltase was obtained. The sucrase showed optimum conditions for action at pH 4 to 5, the amylase at pH 6 to 7, both upon the starch present in the juice and upon added soluble starch. The action of a yeast sucrase preparation upon the juice showed the presence of sucrose (or raffinose) in a concentration of the order of magnitude of 1 per cent. 相似文献
15.
C Icard-Liepkalns V A Liepkalns T E Webb 《Biochemical and biophysical research communications》1983,110(1):96-102
Using labelled single copy DNA to cytoplasmic messenger RNA from a glioma cell line, it is shown by the excess RNA hybridization technique that a human glioma and a human fetal brain cell line both contain the mid and low abundancy classes of cytoplasmic messenger RNA. However, the high abundancy class present in the glioma cells is absent from the hybridization profile of the fetal cell line. Most of the nuclear RNA species complementary to this single copy DNA were present in the low abundancy class of both cell types; the mid-abundancy class was present in much lower concentration than in glioma cytoplasmic RNA and the high abundancy class was essentially absent. The extent of formation of S1-nuclease resistant hybrids indicated that some of the messengers which are present in the high abundancy class in the cytoplasm of glioma cells are present in the lower abundancy classes of fetal brain cells. Thus the glioma cells appear to exhibit a higher degree of specialization potential than the embryonic cells. 相似文献
16.
J W Phillips F J Hird 《Comparative biochemistry and physiology. B, Comparative biochemistry》1977,57(2):127-131
1. The hypothesis is advanced that it would be logical for a tissue (liver) to evolve as a gluconeogenic organ in order to recover the lactate produced as a result of rapid and sustained contraction of skeletal muscle. 2. Lactate was present in skeletal muscle of all animals examined and increased following electrical stimulation. It was also present in the blood. 3. Gluconeogenesis from lactate occurred in liver slices of all animals excepting amphibia. However, livers of these animals also contained much glycogen and are probably gluconeogenic. 4. Phosphoenolpyruvate carboxykinase was present in all animals investigated; pyruvate carboxylase was present in all animals excepting the toad. 相似文献
17.
Jesper Hedal Kløverpris Kenneth Baltzer Per H. Nielsen 《The International Journal of Life Cycle Assessment》2010,15(1):90-103
Background, aims and scope
Most life cycle inventory data for crops do not include the ultimate (marginal) land use induced by crop consumption. The aims of this study were to present, document and discuss a method which can solve this problem and, furthermore, to present concrete examples for wheat consumption in Brazil, China, Denmark and the USA. A global scope is applied and the simulated adaptation to increased wheat demand corresponds to a long-term temporal scope under present market conditions with present technology. 相似文献18.
K L Rock L Rothstein C Fleischacker S Gamble 《Journal of immunology (Baltimore, Md. : 1950)》1992,148(10):3028-3033
Ag in the extracellular fluids can be internalized, processed, and presented in association with class I MHC molecules on specialized APC in normal spleen. We examine the fate of these APC after they present Ag to a CTL. When splenocytes present exogenous OVA to CTL, their ability to subsequently present native Ag in association with both class I and class II molecules is inhibited. CTL do not inhibit the ability of splenocytes to present processing independent peptides with class I or class II molecules. Inhibition of Ag presentation is only observed in the presence of the specific Ag recognized by the CTL. This inhibition is MHC-restricted. In the presence of specific Ag, CTL inhibit the ability of APC to present unrelated Ag. However, bystander APC are not affected by activated CTL. Taken together these results indicate that when APC present exogenous Ag to CTL, they are inhibited or killed. The CTL that mediates this activity has a conventional CD4-CD8+ phenotype and utilizes a TCR-alpha beta. The potential significance of these findings and their possible relationship to phenomena associated with Ts cells are discussed. 相似文献
19.
In the present paper the frequencies of individuals without middle phalangeal hair was found as 55.75% in the Tibetan males and 68.61% in females. Sex differences were noticed in the present sample. Populations of Mongoloid affinity seems to have a marked increase in the frequency of individuals without phalangeal hair and the present Tibetan sample reflects this tendency. 相似文献
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