The photoaffinity label [γ-32P]8-N3GTP has been used to identify GTP-binding components in highly purified preparations of GTPase from bovine rod outer segments. These preparations contain two major polypeptides of 37,000 and 39,000 daltons. In the presence of photolyzing radiation, [γ-32P]8-N3GTP is covalently attached to the 37,000 dalton polypeptide. Tryptic peptide mapping of this polypeptide indicates that it is highly related to the 39,000 dalton species that has been previously identified as a GTP-binding component. 相似文献
The 45-kDa alpha subunit of the signal transducing Gs protein complex, which stimulates receptor-coupled adenylate cyclase, incorporated less of the photoaffinity probe, 8N3-[gamma-32P]GTP, in extracts from tumorigenic cell lines in comparison with nontumorigenic cell lines derived from mouse lung epithelium. Immunoblotting experiments using anti-Gs alpha antibodies demonstrated that tumor cells do not have a decreased amount of Gs alpha and photolabeling of tumor cell Gs alpha increased when the rate of nucleotide exchange was promoted. Therefore, tumor cell Gs alpha function may be altered. Consistent with this hypothesis is the observation that the tumor cells exhibited decreased responsiveness to the beta-adrenergic agonist, isoproterenol. Gs alpha photolabeling in growing nontumorigenic cells was reduced to a level resembling that observed in tumor cells, but photolabeling increased when cells became contact-inhibited. This increase in 8N3-[gamma-32P]GTP incorporation into Gs alpha by normal cells at confluence was not seen in the tumorigenic cells. Since Gs alpha photolabeling was inversely proportional to the percentage of [3H]thymidine-labeled nuclei at confluence, we suggest that the altered Gs alpha in tumor cells is involved in the loss of cell growth regulation. 相似文献
Restriction fragment length polymorphisms (RFLPs) were revealed at the porcine casein loci with the following combinations of restriction endonucleases and porcine cDNA clones: αs1,-casein (TaqI); αs2-casein (BamHI); and ß-casein (Sacl). These RFLPs were shown to be under simple monogenic control by segregation analysis of two- and three-generation families. The CASAS1, CASAS2 and CASB casein loci were also shown to be linked with no recombinant haplotypes observed amongst 77 meioses in Large White and Meishan F1 and F2 crosses. No recombinants were observed in a further 106 meioses that were informative for linkage between CASAS1 and CASAS2. 相似文献
Horned beetles are emerging models in the study of coevolution between novel morphologies and behavior. In Onthophagus beetles, large males use horns to fight other males in brood tunnels while small males with higher mobility sneak around the large males to gain access to females. Mating tactics have rarely been described in other dung beetle genera. We studied the horned dung beetle Sulcophanaeus velutinus that exhibits two parallel horns on the prothorax and one on the head. We put two males of different horn lengths, but similar mass, in observation chambers and found that the large male with longer horns won access to the female in physical competition. Speed tests in artificial tunnels show that locomotion is impeded in large males, suggesting an advantage in mobility for males with small horns. This work contributes to the limited existing evidence on the function of alternative morphologies in horned dung beetles taxa. 相似文献
The integration of high-quality, genome-wide analyses offers a robust approach to elucidating genetic factors involved in complex human diseases. Even though several methods exist to integrate heterogeneous omics data, most biologists still manually select candidate genes by examining the intersection of lists of candidates stemming from analyses of different types of omics data that have been generated by imposing hard (strict) thresholds on quantitative variables, such as P-values and fold changes, increasing the chance of missing potentially important candidates.
Methods
To better facilitate the unbiased integration of heterogeneous omics data collected from diverse platforms and samples, we propose a desirability function framework for identifying candidate genes with strong evidence across data types as targets for follow-up functional analysis. Our approach is targeted towards disease systems with sparse, heterogeneous omics data, so we tested it on one such pathology: spontaneous preterm birth (sPTB).
Results
We developed the software integRATE, which uses desirability functions to rank genes both within and across studies, identifying well-supported candidate genes according to the cumulative weight of biological evidence rather than based on imposition of hard thresholds of key variables. Integrating 10 sPTB omics studies identified both genes in pathways previously suspected to be involved in sPTB as well as novel genes never before linked to this syndrome. integRATE is available as an R package on GitHub (https://github.com/haleyeidem/integRATE).
Conclusions
Desirability-based data integration is a solution most applicable in biological research areas where omics data is especially heterogeneous and sparse, allowing for the prioritization of candidate genes that can be used to inform more targeted downstream functional analyses.
Recently, several studies on the effects of a compound named “chromium malate,” with the proposed formula “Cr2malate3·xH2O” where x = 3.5 or 5, on the health of healthy and diabetic rats have appeared. However, the compound is poorly characterized, and knowing the identity of this material could be important in the interpretation of the previous and of future studies on the effects of this compound in animals. Consequently, the synthesis, characterization, and identity of this material were explored. A combination of spectroscopic, magnetic, and elemental analyses and mass spectral studies reveal that the compound is probably a polymer, not a discrete molecule, and does not have the composition previously reported. The repeating unit of the polymer possesses an antiferromagnetically coupled trinuclear Cr(III) core. The current study suggests that previous reports on chromium malate and its effects in animals must be viewed with caution.
Bear's Hiding Place: Ishi's Last Refuge. 1998. 18 minutes, color. video by Jed Riffe. For more information, contact University of California Extension, Center for Media and Independent Learning, 2000 Center Street. Fourth Floor, Berkeley. CA 94704. 相似文献
The initial steps in taste and olfaction result from the activation by
chemical stimuli of taste receptor cells (TRCs) and olfactory receptor
neurons (ORNs). In parallel with these two pathways is the chemosensitive
trigeminal pathway whose neurons terminate in the oral and nasal cavities
and which are activated by many of the same chemical stimuli that activate
TRCs and ORNs. In a recent single unit study we investigated the responses
of rat chorda tympani and glossopharnygeal neurons to a variety of
bitter-tasting alkaloids, including nicotine, yohimbine, quinine,
strychnine and caffeine, as well as capsaicin, the pungent ingredient in
hot pepper. Here we apply many of these same compounds to cultured rat
trigeminal ganglion (TG) neurons and measure changes in intracellular
calcium [Ca2+]i to determine whether TG neurons will respond to these same
compounds. Of the 89 neurons tested, 34% responded to 1 mM nicotine, 7% to
1 mM caffeine, 5% to 1 mM denatonium benzoate, 22% to 1 mM quinine
hydrochloride, 18% to 1 mM strychnine and 55% to 1 microM capsaicin. These
data suggest that neurons from the TG respond to the same bitter-tasting
chemical stimuli as do TRCs and are likely to contribute information sent
to the higher CNS regarding the perception of bitter/irritating chemical
stimuli.
相似文献
Summary A series of 1,2-dihydro-s-triazines has been studied inLactobacillus casei # 7469-pteroylglutamic acid systems. The active derivatives exhibit a competitive inhibition similar to that of 4-aminopteroylglutamic
acid, but differ from the latter in that inhibition is not relieved by adenine or guanine, and at appropriate concentrations
of inhibitor, is not reversed by excess pteroylglutamic acid. Differences in microbiological activity can be correlated with
certain alterations in the structure of the molecule, maximum activity being exhibited by the 2,2-dimethyl-phenyl- and 2,2-dimethyl-m-chlorophenyl derivatives.
The inhibitory effect of these compounds is reversed·by appropriate concentrations of dihydropteroylglutamic acid, N10-formylpteroylglutamic acid, synthetic and natural citrovorum factor, thymine and thymidine. The similarity in inhibition
indices obtained vs the various forms of pteroylglutamic acid inLactobacillus casei bioassay systems and the correlation with those vs citrovorum factor inStreptococcus faecalis # 8043 andLeuconostoc citrovorum # 8081 bioassay systems suggests that inhibition ofLactobacillus casei is the result of interference with the utilization of citrovorum factor.
Part I: J. Amer. Chem. Soc.74, 855, 1952; Amer. J. Path.28, 599, 1952; II: J. Amer. Chem. Soc. 1955, in press; III: J. Amer. Chem. Soc. 1955, in press; IV: Proc. Soc. Exp. Biol. Med.83, 733, 1953; V: Proc. Soc. Exp. Biol. Med.83, 740, 1953; VI: Proc. Soc. Exp. Biol. Med.83, 742, 1953.
The experimental work for this and studies VIII, IX, and X in this series was done in part at the Laboratorium voor de Gezondheidscleer,
Universiteit van Amsterdam, Nederland, which is directed by Professor DrA. Charlotte Ruys, and these four reports are based upon a thesis submitted by G.E.F. to the Faculteit der Wis-en Natuurkunde, in partial fulfiment
of the requirements for the degree of Doctor of Science. 相似文献