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111.
112.
A mathematical model for the interaction ofBdellovibrio and its prey predicted that a relatively high prey density (7×105 cells ml–1) would be required for the establishment of an equilibrium in a mixed population [8]. The present report shows thatBdellovibrio can be maintained in a continuous culture when the prey cell density is much lower (2–5×104 cells ml–1), and closer to that of naturally occurring bacterial populations in sea waters. 相似文献
113.
GTP catabolism induced by sodium azide or deoxyglucose was studied in purine nucleoside phosphorylase (PNP) deficient human B lymphoblastoid cells. In PNP deficient cells, as in control cells, guanylate was both dephosphorylated and deaminated but dephosphorylation was the major pathway. Only nucleosides were excreted during GTP catabolism by PNP deficient cells and the main product was guanosine. The level of nucleoside excretion was largely affected by intracellular orthophosphate (Pi) level. In contrast, normal cells excreted nucleosides only at low Pi level while at high Pi levels, purine bases (guanine and hypoxanthine) were exclusively excreted. PNP deficiency had no effect on the extent of GMP deamination. 相似文献
114.
115.
Diane Willenbrock McNees Roscoe W. Lewis Betty J. Ponzio Raymond F. Sis Frank J. Stein 《Primates; journal of primatology》1984,25(1):103-109
Blood chemistry values were collected over a three-year period from at least 10 colony-born and 24 wild-born apparently normal
common marmosets. BUN, SGOT, creatinine, calcium, phosphorus, alkaline phosphatase, protein, albumin, cholesterol, triglycerides,
uric and glucose values were determined. A statistical comparison of baseline values was made between wild-born, colony-born,
male and female marmosets. Also the same comparison was made between common marmosets and cotton-top tamarins, white lipped
tamarins and human subjects. 相似文献
116.
The clinical records of 27 adolescent children of physicians who were treated in a psychiatric unit for adolescents were studied. Most of the children had been referred by their physician fathers for evaluation of conduct or mood disorders. These referrals were often the focus of family distress. There appeared to be no typical syndrome presented by physicians'' children. Those treating such patients should be especially sensitive to the possibility that parental denial will increase the patient''s resistance to therapy. Family therapy, an effective treatment for psychologic problems in adolescents, is often avoided by physicians. 相似文献
117.
118.
Joseph P. Stein James F. Catterall Paula Kristo Anthony R. Means Bert W. OMalley 《Cell》1980,21(3):681-687
Two thirds of the natural chicken ovomucoid gene has been sequenced, including all exons and the intron sequences surrounding all fourteen intron/ exon junctions. The junction sequences surrounding four of the introns are redundant; however, the sequences surrounding the other three introns contain no redundancies and thus the splicing sites at either end of these three introns are unambiguous. The splicing in all cases conforms to the GT-AG rule. The ovomucoid gene sequence around intron F can be used to predict the cause of an internal deletion polymorphism in the ovomucoid protein, which is an apparent error in the processing of the ovomucoid pre-mRNA. We also compare the structural organization of the ovomucoid gene with the ovomucoid protein sequence to examine theories of the evolution of ovomucoids as well as the origin of intervening sequences. This analysis suggests that the present ovomucoid gene evolved from a primordial ovomucoid gene by two separate intragenic duplications. Furthermore, sequence analyses suggest that introns were present in the primordial ovomucoid gene before birds and mammals diverged, about 300 million years ago. Finally, the positions of the introns within the ovomucoid gene support the theory that introns separate gene segments that code for functional domains of proteins and provide insight on the manner by which eucaryotic genes were constructed during the process of evolution. 相似文献
119.
Stein LS 《The Western journal of medicine》1980,133(2):176-178
120.
Carl L. Keen Bo Lönnerdal Theodore N. Stein Lucille S. Hurley 《Biological trace element research》1980,2(3):221-227
The presence of superoxide dismutase in bovine and human milk was investigated by ultrafiltration, gel filtration, and isoelectric
focusing. Conclusive evidence for the presence of this enzyme in both milks is presented. The molecular weight of the enzyme
was estimated by gel filtration on Sephadex G-100 to be 30,000, which is consistent with reported values for the copper, zinc
form of superoxide dismutase. In addition, enzyme activity was inhibited by cyanide, thus eliminating the possibility that
the enzyme was present in the manganese form. Several isoenzymes were detected by isoelectric focusing in polyacrylamide gel,
and the isoenzyme pattern in bovine milk was the same as that found for bovine plasma, suggesting that milk superoxide dismutase
originates from plasma. It may be that the presence of copper, zinc superoxide dismutase in milk is important for the maintenance
of its oxidative stability. 相似文献