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111.
Milk and plasma samples from the Southern fur-seal (Arctocephalus tropicalis gazella) , collected from animals shot between 0 and 26 days post-partum , have been analysed. The aqueous phase of milk (ultracentrifugate) was hyperosmotic to plasma by about 35 m-osmol/kg water but contained no lactose. The osmolality of milk could be accounted for by the ionic content, of which sodium and potassium (in approximately equal amounts) were the main cations. The fat content of the milk was very high (approximately 40%), except in very early lactation (0 and 1 day post-partum). The concentrations of chloride, calcium, magnesium, phosphate and citrate in the aqueous phase are given. Major differences between the composition of fur-seal milk and that of other mammals are pointed out, and discussed in relation to water conservation, energy and fat supply, and prolonged milk storage in this snecies. 相似文献
112.
Ogle Jane W. Lange R. D. Dunn C. D. R. 《In vitro cellular & developmental biology. Plant》1978,14(11):945-950
Summary The in vitro production of the important regulatory of erythropoiesis, erythropoietin (Epo), is reviewed. It is concluded
that it is possible to produce almost routinely small quantities of Epo in tissue culture. Although such procedures offer
the potential to provide large quantities of the hormone for clinical use, the optimum culture conditions and mechanisms for
triggering Epo production have yet to be resolved.
This work was supported by Grants No. 74444 from The John A. Hartford Foundation, and HL 10567 from the National Institutes
of Health. 相似文献
113.
Jane Overton 《Developmental biology》1977,55(1):103-116
The frequency of desmosome formation was examined in aggregates of old cells, which form many junctions, combined with young cells, which form few. Cells of chick corneal epithelium and mouse epidermis, which can be distinguished morphologically, were combined. Desmosomes between these cell types are stable. Further, young cells make more desmosomes than they otherwise would on those surfaces adjoining old cells. Desmosomes increase in number in aggregates while cell sorting is occurring. Cells consistently sort, with those which form most desmosomes lying internally. Gap junctions and intermediate junctions are also present, but are uncommon. A carbohydrate cell-surface coat has regenerated by the time desmosome formation starts. The possible relation of desmosome formation to cell sorting is discussed. 相似文献
114.
Acetylation of the amino terminal serine of the β chains of cat HbB occurs during synthesis of hemoglobin in a mRNA dependent rabbit reticulocyte lysate protein synthesizing system in the presence of acetyl-CoA and cat reticulocyte mRNA. Both of the major cat hemoglobins, the nonacetylated HbA and acetylated HbB, are synthesized efficiently in the rabbit lysate system. The acetylation of HbB-β chains occurs during the biosynthesis of these proteins. Radioautography of tryptic peptide maps reveals that acetylation occurs specifically at the amino terminal serine of HbB-β globin, and not on HbA-β globin or on the α chain common to both hemoglobins A and B. Because of the similarity of the structures of HbA-β and HbB-β globin, it is suggested that the amino terminal residue determines whether the peptide chain is recognized for acetylation by a ribosomal acetyltransferase. 相似文献
115.
116.
Jane Smith Ian Furner Z. R. Sung 《In vitro cellular & developmental biology. Plant》1981,17(4):315-321
Summary The purpose of this study was to optimize growth conditions for a strain of haploid carrot callus and to follow its karyotypic
changes in a long span of time. The strain has been maintained in liquid suspension since September 1977. It has remained
predominantly haploid in its karyotype since that time. The original explant was initiated and subsequently subcultured in
Gamborg's B5 medium. The components of the B5 medium were omitted one at a time and sequentially added back to determine their
minimum, optimum, and maximum nontoxic concentrations. These changes were made in the original formula: the addition of an
organic buffering agent and an increase in the iron and other micronutrient concentrations. Using this slightly modified B5
medium, we assessed the effect on growth by single additions of amino acids, different carbon sources, growth regulators,
and vitamins. No improvement in plating efficiency resulted from addition of any of these compounds. We conclude that there
are factors limiting the plating efficiency of the haploid cells other than these tested, or that single additions will not
make a discernible difference, or that growth promoting factors cannot be exogenously supplemented to cultured cells. 相似文献
117.
Paul F. Hamlyn Rosemary E. Bradshaw Fiona M. Mellon Claro M. Santiago Jane M. Wilson John F. Peberdy 《Enzyme and microbial technology》1981,3(4):321-325
Several commercial polysaccharases have been compared for their ability to liberate protoplasts from fungi. These enzymes were found to contain side activities capable of hydrolysing fungal cell walls. Protoplasts have been commonly isolated from fungi using enzyme systems prepared by workers in their own laboratories. However, these procedures are time consuming and considerable variation may be found between different batches of enzyme. The present study shows that high yields of protoplasts can be prepared from a variety of fungi using relatively cheap commercial enzymes. The yields obtained were normally as good as or better than those previously produced. 相似文献
118.
119.
Henry Taylor Jane Teas Thomas Richie Charles Southwick Ram Shrestha 《Primates; journal of primatology》1978,19(2):343-351
In 1,506 hours of field observations on free-ranging rhesus monkeys in Kathmandu Valley, Nepal, in 1974 and 1975 18 cases
of favorable social interactions between adult males and infants were observed. Eleven of these were brief encounters of play
or grooming; seven were more extended cases of male care. One of the latter was a complete adoption of a neonatal orphan by
a dominant male. This adoption was possessive and restrictive and it resulted in the death of the infant by starvation within
three days. A similar adoption involving the same male occurred in 1976 and it also resulted in the death of the infant. Most
of the favorable male-infant interactions occurred during the winter and spring when the infants were 6 to 12 months of age.
These favorable social interactions involved eight males in six different troops, out of a total of about 48 males in 12 troops
in our study population of approximately 600 monkeys. These observations are discussed in light of current sociobiological
theories. 相似文献
120.
[4-14C]Estrone was injected intramuscularly into two mature laying Rhode Island Red hens. Radioactive steroids and steroid conjugates recovered from the urine on Amberlite XAD-2 columns were fractionated on columns (100 cm) of DEAE-Sephadex A-25 by NaCl gradients. The presences of the following were confirmed, the figures in brackets indicating average proportions as per cent of total radioactivity recovered after Sephadex column chromatography: -the 3-β-glucuronides of estrone (10. 9) and of estradiol-17α plus estradiol-17β(9.8); the 17-β-glucuronides of estradiol-17α plus estradiol-17β (2.1); the 3-sulfates of estrone (14. 5) and of estradiol-17α plus estradiol-17β (27. 4); and the disulfates of estradiol-17α plus estradiol-17β (2. 3). The following additional conjugates were identified:-a β-glucuronide of 16-epiestriol (0.2) and a β-glucuronide of 16-ketoestradiol-17β (0. 2); the 3-sulfates of 16-epiestriol (1. 4), of 17-epiestriol (0. 9), of 16, 17-epiestriol (0. 7), of 16-keto-estradiol-17β (1. 1), and of 2-methoxyestrone (0. 7). Some evidence was obtained for the presence of 16, 17-epoxy-estratrienol-3-sulfate (1.9). 相似文献