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31.
The metabolism of the isomeric decalones 总被引:5,自引:5,他引:0
1. The metabolism of (+/-)-cis-1-, (+/-)-trans-1-, (+/-)-cis-2- and (+/-)-trans-2-decalone in the rabbit has been investigated. 2. (+/-)-cis-2- and (+/-)-trans-2-Decalone were both reduced to racemic secondary alcohols, conformationally related to the ketones administered, and possessing an equatorial hydroxyl group. These alcohols were excreted in the urine as glucuronides in amounts equal to about half the dose administered. The glucuronides were isolated both as triacetyl methyl esters and as sodium salts. The ester obtained after feeding with (+/-)-cis-2-decalone proved to be methyl (cis-cis-2-decalyl tri-O-acetyl-beta-d-glucosid)uronate, whereas (+/-)-trans-2-decalone yielded methyl (trans-cis-2-decalyl tri-O-acetyl-beta-d-glucosid)uronate. The sodium salts were shown to be sodium (cis-cis-2-decalyl glucosid)uronate and sodium (trans-cis-2-decalyl glucosid)uronate. 3. Enzyme hydrolysis of the sodium salts and acid hydrolysis of the esters derived from (+/-)-cis-2-decalone yielded (+/-)-cis-cis-2-decalol, and of those from (+/-)-trans-2-decalone yielded (+/-)-trans-cis-2-decalol. 4. (+/-)-cis-1-Decalone was reduced mainly to (-)-cis-cis-1-decalol and excreted as [(-)-cis-cis-1-decalyl glucosid]-uronic acid. A small amount of the corresponding (+)-isomer was produced, yielding [(+)-cis-cis-1-decalyl glucosid]uronic acid on isolation. Enzyme hydrolysis of these compounds gave the corresponding aglycones; both alcohols possessed an equatorial hydroxyl group. 5. (+/-)-trans-1-Decalone was reduced to (+)-trans-trans-1-decalol, with an equatorial hydroxyl group, and in smaller amount to (+)-trans-cis-1-decalol possessing an axial group. The former alcohol was excreted as [(+)-trans-cis-1-decalyl glucosid]uronic acid, and the latter as [(+)-trans-cis-1-decalyl glucosid]uronic acid. 6. From a knowledge of the conformations, and in some cases the absolute configurations, of the compounds administered and excreted, and by making the assumption that the coenzyme concerned in the reductions is NADH (or NADPH), an explanation of the above findings in terms of steric hindrance and thermodynamic stability is given. 相似文献
32.
Improved Temperature-Gradient Incubator and the Maximal Growth Temperature and Heat Resistance of Salmonella 总被引:2,自引:1,他引:1 下载免费PDF全文
An improved all-metal temperature-gradient incubator produces its gradient by means of a bar permanently installed in a near-vertical position with its lower end in a cool constant-temperature water bath and with thermostatically controlled heaters near its top. Bolts hold the incubator in contact with the temperature-gradient bar, and polyurethane foam insulates the entire assemblage during use. Maximal growth temperatures of 34 representative strains of Salmonella were found to be between 43.2 and 46.2 C. In an agar medium with an initial level of 106 cells per milliliter, no strain survived 50 C for 48 hr. S. senftenberg 775W showed no greater heat resistance at or near 48 C than did other species or other S. senftenberg strains. However, it was considerably more resistant than other strains at 55 C. 相似文献
33.
Effect of melatonin infusion duration and frequency on gonad, lipid, and body mass in pinealectomized male Siberian hamsters 总被引:2,自引:0,他引:2
The goal of this study was to discriminate between two hypotheses regarding how the circadian rhythm of pineal melatonin (MEL) production transmits photoperiodic information: (1) A circadian rhythm of sensitivity to MEL regulates the hormone's effect; (2) the duration of the MEL signal, rather than its circadian timing, is the critical parameter of the MEL rhythm. The experiment examined the response of pinealectomized (PINX) male Siberian hamsters to 10-hr (short-day-type) versus 6-hr (long-day-type) duration MEL infusions (10 ng/infusion) in cycles with period lengths (T) of 18, 24, 36, and 48 hr. After cannula implantation, animals were moved from LD 16:8 to LD 10:14 (lights-on from 0500 to 1500 hr, EST), where the timed infusions began. Additional T 24 cycles included as controls employed 18-hr MEL, 18-hr saline (SAL), and 10-hr SAL infusions: Body weight and food intake were measured weekly. After 6 weeks, animals were killed; blood samples were taken for radioimmunoassay (RIA) of serum follicle-stimulating hormone (FSH) and prolactin (PRL); and terminal body, epididymal white adipose tissue (EPIWAT), and paired testis weights were recorded. Six-hour MEL infusions failed to induce short-day-type effects, regardless of the period (T) of the infusion cycle. In contrast, compared to SAL and 6-hr MEL infusions, 10-hr MEL resulted in decreases in body, EPIWAT, and testis weights in T 24, but not in T 36 or T 48. In T 18, testis, body, and EPIWAT mass were decreased, but not to the same extent as in T 24. Similarly, daily 18-hr MEL infusions (T24) were less effective as a short-day stimulus than were 10-hr MEL infusions. The effectiveness of 10-hr, but not 6-hr, MEL infusions in T 18 and T 24 is consistent with the duration hypothesis and argues against the circadian hypothesis. Neither hypothesis could have predicted that all infusion cycles of T greater than or equal to 36 hr, regardless of the infusion durations, would fail to elicit short-day-type responses. This outcome suggests a need for relatively frequent (T less than 36 hr) MEL stimulation in addition to the requirement for adequate duration of each MEL infusion. 相似文献
34.
Summary Human recombinant interleukin-1 (HrIL-1) inhibited WEHI-3B cell growth in a dose-related manner (10–10000 U/ml). Prostaglandin E2 at high concentrations (1000 ng/ml) also inhibited cell growth. When added together, HrIL-1 and prostaglandin E2 inhibited WEHI-3B growth in a synergistic manner (HrIL-1 concentrations of 10–10000 U/ml and prostaglandin E2 concentrations of 10–1000 ng/ml). In contrast to the effects of the cyclooxygenase metabolite of arachidonic acid leukotriene C4, a lipoxygenase metabolite, reversed the cytostatic action of HrIL-1. 相似文献
35.
Some pseudomonads produce a toxin that specifically inhibits winter wheat (Triticum aestivum L.) root growth and the growth of several microorganisms. The toxin does not inhibit pea (Pisum sativum) root growth, but the organisms are aggressive root colonizers and their effect on Rhizobium leguminosarum growth, colonization, and nodulation of peas was not known. Peas were grown in Leonard jars in the greenhouse. Pea roots
were inoculated with R. leguminosarum, a toxin-producing Pseudomonas sp., both, or neither (control). The Pseudomonas sp. colonized pea roots more rapidly and in greater number than R. leguminosarum after ten days. In the presence of the Pseudomonas sp., the R. leguminosarum population on the rhizoplane was less at ten days. When the roots were inoculated with both R. leguminosarum and Pseudomonas sp., the number of nodules were greater than when R. leguminosarum was inoculated alone, but nodule dry weight and pea shoot biomass were similar to plants inoculated with only R. leguminosarum. Although these results need confirmation with non-sterile soil and field studies, these preliminary results indicate that
peas will not be affected by wheat root-inhibitory rhizobacteria. 相似文献
36.
E Delorme T Lorenzini J Giffin F Martin F Jacobsen T Boone S Elliott 《Biochemistry》1992,31(41):9871-9876
The erythropoietin (EPO) molecule contains four carbohydrate chains. Three contain N-linkages to asparagines at positions 24, 38, and 83, and one contains an O-linkage to a serine at position 126. We constructed human EPO variants that eliminated the three N-glycosylation sites by replacing the asparagines with glutamines singly or in combination. The O-linked carbohydrate chain was removed by replacing the serine with glutamine, valine, histidine, or alanine. A variant with a double mutation (Gln38,83) and another with a triple mutation (Gln24,38,83) were secreted poorly from COS1 and CHO cells even though RNA encoding these variants was present. All other variants with mutations in N-linked glycosylation sites were secreted normally. Removal of any of the N-glycosylation sites reduced the in vivo but not the in vitro biological activity of the EPO molecule. All the mutations at Ser126, the O-glycosylation site, were secreted normally. In vitro activity was also unaffected except for Ala126 which had a 50-fold decrease. The Val126 variant was tested in vivo, and its specific activity was only slightly less than that of the native EPO, which indicates that the O-linked carbohydrate is not essential for activity. 相似文献
37.
A Huszczuk B J Whipp T D Adams A G Fisher R O Crapo C G Elliott K Wasserman D B Olsen 《Journal of applied physiology》1990,68(6):2604-2611
To determine the role of cardiac reflexes in mediating exercise hyperpnea, we investigated ventilatory responses to treadmill exercise in seven calves with artificial hearts and seven controls. In both groups, the ventilatory responses were adequate for the metabolic demands of the exercise; this resulted in regulation of arterial PCO2 and pH despite the absence of cardiac output increase in the implanted group. In this group, there was a small but significant reduction of arterial PO2 by 4 +/- 3 Torr and a rise of blood lactate by 1.1 +/- 1 mmol/l. When cardiac output was experimentally increased in the implanted calves to a level commensurate with that spontaneously occurring in the control calves, ventilation was not affected. However, experimental reductions of cardiac output led to an immediate augmentation of exercise hyperpnea by 4.56 +/- 4.3 l/min and a further significant lactate increase of 1.2 +/- 1.22 mmol/l that was associated with a significant decrease in the exercise O2 consumption (0.32 +/- 0.13 l/min). These observations indicate that neither cardiac nor hemodynamic effects of increased cardiac output constitute an obligatory cause of exercise hyperpnea in the calf. 相似文献
38.
39.
The paper describes the local, national, European and wider-area framework, statutes, and formal and voluntary mechanisms for managing European estuaries. These aspects are discussed in relation to two large and representative estuarine systems, the Tagus, Portugal, and the Humber, on the English North Sea coast As estuaries are sites of many activities and uses, most of which are encouraged or at least condoned, management has the role of preventing and resolving conflicts between those uses and users. Accepted uses of estuaries include the discharge and dumping of waste materials, fin and shell-fisheries, conservation, land reclamation, natural usage, abstraction by industry, and recreation. Estuarine management is now being carried out within the constraints of local and regional government planning, planning and activities of water pollution control bodies, fisheries control bodies, and navigation and port authorities The Tagus and Humber estuaries support all of the above activities and uses, and have controls within a European legislative framework but have differing histories of management and planning in order to resolve conflicts. In addition the Humber is subject to controls placed on North Sea areas. The paper discusses the relevant national and European legislation (Directives) and accepted practices for management. Furthermore, the paper discusses the formulation and practice of estuarine management plans as used by various bodies (nature conservation, water quality and regional authority). It is of particular note that the lessons from these two estuaries are relevant to many other European estuaries. 相似文献
40.
The extreme carboxyl terminus of the equine herpesvirus 1 homolog of herpes simplex virus VP16 is essential for immediate-early gene activation. 总被引:1,自引:1,他引:0 下载免费PDF全文
G D Elliott 《Journal of virology》1994,68(8):4890-4897
Gene 12 of equine herpesvirus 1 (EHV-1), the homolog of herpes simplex virus (HSV) VP16 (alpha TIF, Vmw65), was cloned into a eukaryotic expression vector by PCR and used in transactivation studies of both the EHV-1 and HSV-1 IE1 promoters. Results demonstrated that the product of gene 12 is a potent transactivator of immediate-early gene expression of both viruses, which requires sequences in the upstream HSV-1 promoter for activity. Mutational analysis of the gene 12 open reading frame indicated that removal of the C-terminal 7 amino acids, which contain a short region of homology with the extreme C terminus of VP16, inactivated the protein. Within this region, only a single methionine residue appeared to be essential for activity, implying that gene 12 may have a modular array of organization similar to that of VP16. However, fusion of the gene 12 C terminus to a truncated form of VP16, which contained the complex formation domain, did not restore activity to the HSV-1 protein. These data demonstrate that the EHV-1 immediate-early transactivator may not be functionally colinear with VP16, with transactivation requiring both the C terminus and another region(s) present within the N-terminal portion. 相似文献