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2.
Marianne Bouvier 《American journal of primatology》1988,15(2):129-142
A new technique has been developed for estimating age in rhesus macaques (Macaca mulatta) that is based on mandibular measurements and has several advantages over presently available techniques. First, the new technique is relatively quick and inexpensive because a single measurement or radiograph suffices to produce an age estimate. Second, mandibular growth represents a more continuous phenomenon than either epiphyseal union or dental eruption; therefore, age estimates may be made throughout the period of growth without significant gaps in the process. Finally, the new technique may be used on incomplete or even fragmentary skeletal material because it requires that only a portion of the mandible be preserved. The new technique produces age estimates with a prediction error of ±5.08 months in males and ±7.29 months in females. These errors are only slightly higher than those found previously for dental eruption or epiphyseal union data. 相似文献
3.
Marianne E. Walsh Charles M. Collins Thomas F. Jenkins Alan D. Hewitt Jeff Stark Karen Myers 《Soil & Sediment Contamination》2003,12(5):631-645
Fort Greely, Alaska has an extensive complex of weapon training and testing areas located on lands withdrawn from the public domain under the Military Lands Withdrawal Act (PL106-65). The Army has pledged to implement a program to identify possible munitions contamination. Because of the large size (344,165,000 m2) of the high hazard impact areas, characterization of these constituents will be difficult. We used an authoritative sampling design to find locations most likely to contain explosives-residues on three impact areas. We focused our sampling on surface soils and collected multi-increment and discrete samples at locations of known firing events and from areas on the range that had craters, pieces of munitions, targets, or a designation as a firing point. In the two impact areas used primarily by the Army, RDX was the most frequently detected explosive. In the impact area that was also used by the Air Force, TNT was the most frequently detected explosive. Where detected, the explosives concentrations generally were low (<0.05 mg/kg) except in soils near low-order detonations, where the explosive-filler was in contact with the soil surface. These low-order detonations potentially can serve as localized sources for groundwater contamination if positioned in recharge areas. 相似文献
4.
The biosynthesis of glyantrypine from radiolabelled amino acid precursors has been shown experimentally to involve anthranilic acid, tryptophan and glycine. Low values for percentage incorporation of radiolabel into glyantrypine were partly influenced by a complex array of other novel alkaloids shown by the radiolabelling experiments to be related to glyantrypine. Interpretation of radiolabel incorporation from [14C-carboxyl]-anthranilic acid into microbial metabolites seen to contain an anthranilyl moiety in various biosynthetic arrangements is discussed. The possibility of diversion of anthranilic acid from the kynurenine pathway to glyantrypine biosynthesis is recognised. 相似文献
5.
The effect of retinoic acid (RA) on testosterone metabolism was examined in a prostatic cancer cell line of human origin, PC-3. In cells growing as monolayers as well as in cell homogenates RA causes a dose-dependent inhibition of the 5 alpha-reductase activity, thus preventing the conversion of testosterone into its hormonally active metabolite, dihydrotestosterone. Fifty per cent inhibition of the enzyme activity occurred at an RA concentration of 2 x 10(-5)M. The pattern of inhibition was that of a non-competitive inhibitor. However, when incubations were performed in the presence of varying amounts of NADPH, it turned out that RA exerts its effect by competitive inhibition of the cofactor action. Although the severe toxicity of RA precludes its systemic use as a 5 alpha-reductase inhibitory drug in humans, the possible anti-androgenic effect of other, less toxic, retinoids should be investigated. 相似文献
6.
Michael K. Ahlijanian Marianne K. Halford Dermot M. F. Cooper 《Journal of neurochemistry》1987,49(4):1308-1315
The inhibition of adenylate cyclase from rat striatal plasma membranes by guanyl-5'-yl-imidodiphosphate [Gpp(NH)p] and morphine was compared to determine whether Gpp(NH)p-mediated inhibition accurately reflected hormone-mediated inhibition in this system. Inhibition of adenylate cyclase activity by Gpp(NH)p and morphine was examined with respect to temperature, divalent cation concentration, and the presence of Ca2+/calmodulin (Ca2+/CaM). Gpp(NH)p-mediated inhibition was dependent on the presence of Ca2+/CaM at 24 degrees C; the inhibition was independent of Ca2+/CaM at 18 degrees C; and inhibition could not be detected in the presence, or absence, of Ca2+/CaM at 30 degrees C. In contrast, naloxone-reversible, morphine-induced inhibition of adenylate cyclase was independent of both temperature and the presence of Ca2+/CaM. Mg2+ dose-response curves also reinforced the differences in the Ca2+/CaM requirement for Gpp(NH)p- and morphine-induced inhibition. Because Gpp(NH)p-mediated inhibition was independent of Ca2+/CaM at low basal activities (i.e., 18 degrees C, or below 1 mM Mg2+) and dependent on the presence of Ca2+/CaM at higher basal activities (24 degrees C, or above 1 mM Mg2+), the inhibitory effects of Gpp(NH)p were examined at 1 mM Mg2+ in the presence of 100 nM forskolin. Under these conditions, both Gpp(NH)p- and morphine-induced inhibition of adenylate cyclase were independent of Ca2+/CaM. The results demonstrate that the requirement for Ca2+/CaM to observe Gpp(NH)p-mediated inhibition depends on the basal activity of adenylate cyclase, whereas hormone-mediated inhibition is Ca2+/CaM independent under all conditions.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
7.
Indole-3-acetic acid (IAA) and indole-3-ethanol (IEt) were identified in immature seeds of Pinus sylvestris L. by combined gas chromatography-mass spectrometry. Indole-3-methanol was tentatively identified using multiple ion monitoring. Anatomical investigations of seeds, as well as measurements of free and alkali-hydrolysable IAA and IEt, were made during seed development and germination. Levels of free IAA and IEt decreased during seed development. In the later stages of seed maturation most IAA and IEt were present in alkali-hydrolysable forms. Bound IAA and bound IEt rapidly decreased during germination, while levels of free IAA and IEt increased dramatically for a short period. 相似文献
8.
The silicified plates of certain testate amoebae have the necessary characteristics to be useful paleoindicators. These plates are usually abundant and well preserved in sedimentary deposits, where they can be studied using the same preparation techniques developed for other siliceous microfossils. Individual plates can usually be identified to the generic and, in some cases, to the species level. A preliminary survey of plates recorded in the surficial (top centimetre) sediments of 38 Adirondack Mountain (NY) lakes suggests that these testaceans may reflect catchment features (e.g. bog development) more closely than lakewater characteristics. The siliceous, species-specific scales of heliozoans are also shown to preserve in sedimentary profiles. 相似文献
9.
The selenium in mammalian glutathione peroxidase is present as a selenocysteine ([Se]Cys) moiety incorporated into the peptide backbone 41-47 residues from the N-terminal end. To study the origin of the skeleton of the [Se]Cys moiety, we perfused isolated rat liver with 14C- or 3H-labeled amino acids for 4 h, purified the GSH peroxidase, derivatized the [Se]Cys in GSH peroxidase to carboxymethylselenocysteine ([Se]Cys(Cm)), and determined the amino acid specific activity. Perfusion with [14C]cystine resulted in [14C]cystine incorporation into GSH peroxidase without labeling [Se]Cys(Cm), indicating that cysteine is not a direct precursor for [Se]Cys. [14C]Serine perfusion labeled serine, glycine (the serine hydroxymethyltransferase product), and [Se]Cys(Cm) in purified GSH peroxidase, whereas [3-3H]serine perfusion only labeled serine and [Se]Cys(Cm), thus demonstrating that the [Se]Cys in GSH peroxidase is derived from serine. The similar specific activities of serine and [Se]Cys(Cm) strongly suggest that the precursor pool of serine used for [Se] Cys synthesis is the same or similar to the serine pool used for acylation of seryl-tRNAs. 相似文献