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71.
Brian A. Bidlingmeyer Steven A. Cohen Thomas L. Tarvin 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1984,336(1)
A new approach to the pre-column derivatization and analysis of amino acids is described. The method is based upon formation of a phenylthiocarbamyl derivative of the amino acids. The derivatization method is rapid, efficient, sensitive, and specific for the analysis of primary and secondary amino acids in protein hydorlyzates. The liquid chromatographic system allows for the rapid, bonded-phase separation with ultraviolet detection of the common amino acids with 12-min analysis time and a 1-pmol sensitivity. 相似文献
72.
73.
The stored poly(A) + RNA from zoospores of the aquatic fungus Blastocladiella emersonii represents 2.5% of the total RNA and has a model MW of 425,000 daltons and an average poly(A) isostich of 32 bases. The poly(A) + RNA also represents 2.5% of the total RNA from early growth phase cells and has a modal MW of 360,000 daltons and an average poly(A) isostich of 38 bases. The poly(A) + RNA from spores and 2-hr plants contains a structure resistant to RNases T1, T2, and A, which can be labeled with 32PO4 and which will bind to DBAE-cellulose. These characteristics strongly suggest that both the zoospore poly(A) + RNA and the 2-hr cell poly(A) + RNA are capped at the 5′ end; and, hence, it is unlikely that capping is involved in the control of protein synthesis during germination.Approximately 80% of the poly(A) + RNA of the spore is located in the membrane-enclosed ribosomal nuclear cap, and more than 90% of the poly(A) + RNA within the cap is found in the 80S monoribosome and heavier fractions.Synthesis of new poly(A) + RNA occurs very early during zoospore germination, and the labeled poly(A) + RNA rapidly enters the newly organized polysomes. The labeling data for early germination also suggest that cytoplasmic polyadenylation occurs. 相似文献
74.
Steven G. Chrysant M.D.Ph.D. Susan M. Townsend B.S. Robert D. Lindeman M.D. Edward D. Frohlich M.D. 《Life sciences》1977,20(12):1953-1960
The possible effects of renal vasoconstriction from anesthesia and surgery on water excretion after hypotonic volume expansion (HVE) were studied in 18 well conditioned anesthetized dogs, with and without the infusion of phenoxybenzamine and acetylcholine into the renal artery of the cannulated kidney. In 6 dogs (Group 1 - Control) whose renal artery was infused with isosmotic saline, HVE resulted in a bilateral increase in GFR and UV (p < .05). ERPF, Cosm, CH2O, UNaV, UKV, RBF, RVR and MAP did not change significantly. In 6 other dogs (Group 2), whose cannulated kidney was infused with phenoxybenzamine 50 μg/min before and during HVE, GFR increased on the infused side while CH2O and UV increased bilaterally (p < .05). ERPF, Cosm, UNaV, UKV, RBF, RVR and MAP were not affected significantly. The addition of ADH, 2 mu/min into the phenoxybenzamine infusate, decreased ERPF, RBF and RVR bilaterally and CH2O on the infused side (p < .05). It had no effect upon GFR, Cosm, UNaV, UKV and MAP. In another 6 dogs, (Group 3), whose cannulated renal artery was infused with acetylcholine (20 μg/min) before and during HVE, CH2O, UV and RVR increased bilaterally (p < .05). ERPF and RBF decreased bilaterally (p < .05), whereas GFR, Cosm, UNaV and MAP were unaffected. UKV decreased on the infused side (p < .05). The addition of ADH (2 mu/min)_into the acetylcholine infusate, decreased CH2O bilaterally and increased Cosm and UKV on the control side (p < .05). It had no effect on ERPF, GFR, UV, UNaV, RBF, RVR and MAP. These observations suggest that anesthesia and surgery produce renal vasoconstriction and this together with increased ADH release, interfere with water excretion by the kidney. Previous renal vasodilation prevents these influences of anesthesia and surgery. 相似文献
75.
An improved chromatographic assay for muramic acid which is sufficiently sensitive for marine sandy sediments is described; it involves acid hydrolysis, thin-layer chromatography, and gas-liquid chromatography. 相似文献
76.
Potassium tris(oxalato)chromate(III) trihydrate (chromium oxalate) has been shown to be a more useful broadening agent than potassium ferricyanide for the spin label 2,2,6,6-tetramethylpiperidine-N-oxy-4-amine (Tempamine) in thylakoid suspensions. Our data show that chromium oxalate is less permeable than ferricyanide, does not inhibit thylakoid electron transport or photophosphorylation, and is not photoreduced by thylakoids. 相似文献
77.
A novel procedure is described for preparing a plasma membrane fraction from skeletal muscle (i.e., sarcolemma). The procedure entails evacuating the myoplasm from muscle slices as a preliminary step to homogenization and fractionation. The evacuated muscle slices are composed of a stroma-containing sarcolemma, which is then homogenized and fractionated, utilizing a sequence of differential and discontinuous sucrose density gradient centrifugations. On the basis of electron microscopy, selective enzyme markers and α-bungarotoxin binding in innervated and denervated muscles, the fraction most enriched with sarcolemma is recovered from the 0.5/0.7 M interface of a discontinuous sucrose gradient. 相似文献
78.
Inhibition of ovulation by RMI 12,936 was associated with suppression of the pro-oestrous peak of hypothalamic dopamine. The antiovulatory effect was not reversed by administration of oestrogen, was partly reversed by progesterone and was fully reversed by oestrogen and progesterone. Hypophysial sensitivity to LH-RH, known to be reduced by RMI 12,936, remained low when ovulation was restored by steroid treatment. Administration of oestrogen did not restore the pro-oestrous peak of hypothalamic dopamine and ovulation was not induced following administration of L-DOPA in RMI 12,936-treated animals. It was concluded that RMI 12,936 is antioestrogenic as well as antiprogestational, that oestrogen is necessary for induction of full hypothalamic-hypophysial responsiveness to progesterone and that a hypothalamic dopaminergic pathway may have a non-essential role in the control of ovulation possibly associated with increasing hypophysial sensitivity to LH-RH. 相似文献
79.
The proportions of carotenoids responsible for column coloration were determined for a population of the sea anemone Bunodosoma granulifera from Grand Cayman using TLC. This population exhibited a very low degree of polymorphism for these proportions, compared to previously sampled populations from Puerto Rico and Curaçao. In addition to the carotenoid pigment system a second system possessing pigments similar to bilins was found for the first time in this genus. This population was also assayed electrophoretically for enzymes encoded by 12 loci. Analysis of these data suggested that the reduced polymorphism for column color may be the result of selection. Although the proportions of carotenoids varied little, the amount of carotenoid per unit of epidermal tissue varied almost four-fold from 0.05 to 0.19 μg/mg dry wt. 相似文献
80.
Steven A. Levine 《Molecular & general genetics : MGG》1977,150(2):205-209
Summary Catalase deficient mutants (kat) ofSalmonella typhimurium have been isolated. The mutationskatA1, katC6 andkatD9 appear to map at about minute 10 on theSalmonella chromosome. ThekatC6 andkatD9 lesions are complemented by theE. coli F128 (lac+ pro+) episome but thekatA1 lesion is not.KatB2 maps at about minute 100. None of the mutants are oxygen sensitive; they grow as well as wild type bacteria, even when aerated. 相似文献