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1.
2.
The rudimentary locus of Drosophila melanogaster 总被引:7,自引:0,他引:7
W A Segraves C Louis S Tsubota P Schedl J M Rawls B P Jarry 《Journal of molecular biology》1984,175(1):1-17
3.
Cycling of soil carbon in the first year after a clear-felling was compared with that before the felling in a Japanese red
pine forest in Hiroshima Prefecture, west Japan. The daily mean temperature at the soil surface in summer was increased after
the felling in comparison to that before felling, and the water content of both the A0 layer and the surface mineral soil was decreased due to the loss of the forest canopy. The rate of weight loss of the A0 layer was reduced after felling. However, accumulation of the A0 layer rapidly decreased because of the lack of litter supply to the forest floor. Low soil respiration after felling was
mainly caused by the cessation of root respiration. Analysis of annual soil carbon cycling was then conducted using a compartment
model. The relative decomposition rate of the A0 layer decreased whereas that of humus and dead roots in mineral soil increased to some extent after felling. The accumulation
of carbon in mineral soil, however, increased slightly due to the supply of humus from roots killed by the felling. 相似文献
4.
Colicin E2 was partially purified from Escherichia coli W3110. This preparation was remarkably stabilized by bovine serum albumin in a solution at neutral pH, as shown by dilution experiments and tests on heat stability of colicin. One killing unit of colicin E2 was estimated to correspond to one molecule of colicin E2, on the assumption of a molecular weight of 60,000. 相似文献
5.
H Yamamoto M D Miller H Tsubota D I Watkins G P Mazzara V Stallard D L Panicali A Aldovini R A Young N L Letvin 《Journal of immunology (Baltimore, Md. : 1950)》1990,144(9):3385-3391
CD8+ CTL inhibit the replication of HIV and simian immunodeficiency virus of macaques (SIVmac) in PBL and, therefore, are likely to play an important role in containing the spread of the AIDS virus in infected individuals. We have generated a series of gag-specific lytic T lymphocyte clones from PBL: of an SIVmac-infected rhesus monkey. These T cell clones are CD3+CD8+ and are MHC class I-restricted in their target specificity. They are, therefore, CTL. Interestingly, all gag-specific CTL clones, as well as the gag-specific lytic activity of PBL of this monkey, demonstrated specificity for a single 25 amino acid fragment of the SIVmac gag protein. Moreover, they were restricted in their lytic function by a single MHC class I allele. These findings illustrate a powerful method for cloning AIDS virus-specific T lymphocytes and demonstrate a remarkably restricted epitope specificity of this AIDS virus-specific CTL response. 相似文献
6.
7.
Haruo Takeshita Toshihiro Yasuda Daita Nadano Reiko Iida Masao Nakanaga Etsuko Tenjo Kazumi Sawazaki Koichiro Kishi 《Human genetics》1994,94(3):224-230
The main isozyme patterns of desialylated blood plasma or serum -l-fucosidase (FUCA) were found to be almost identical to those of semen, urine, placental extracts, and leukocyte lysates, when detected by polyacrylamide gel isoelectric focusing, and activity staining using the fluorogenic substrate 4-methylumbelliferyl--l-fucopyranoside. Three phenotypes (1, 2-1, and 2) determined from plasma samples were identical to the phenotypes from urine and leukocyte lysates from the same individuals. A population study of plasma samples collected from 485 Japanese individuals indicated that the frequencies of the FUCA11
* and FUCA12
* alleles were 0.7505 and 0.2495, respectively. The mean plasma enzyme activities (+SD) of the three phenotypes were 318.8 ± 116.7 nmol/ml per h for type 1, 268.0 ± 108.3 nmol/ml per h for type 2-1, and 233.2 ± 84.4 nmol/ml per h for type 2. The mean activities of types 1 and 2 suggest that, on average, the FUCA11
* gene product in plasma has about 1.4 times the activity of FUCA12
*. 相似文献
8.
In previous studies a novel lectin-like glycoprotein was isolated from silkworm faeces and shown to recognize sugar chains, especially mannose on the cell surface as an epitope, and to cause aggregation of various types of cells in suspension. However, this substance caused detachment and aggregation of only some types of plated cells, such as QM-RSV cells, which are quail myoblasts transformed with a temperature-sensitive mutant of Rous sarcoma virus (ts-RSV) at 35.5 °C, a permissive temperature for RSV. As described here, during studies on the mechanism of cell detachment and aggregation of QM-RSV cells by this new lectin, some novel biological activities of the lectin were recognized. This lectin was found to bind to immunoglobulins (Ig) specifically at specific amino acid sequences, not via recognition of their molecular conformation. It also recognized the neural cell adhesion molecule (NCAM), which is one of the members of the Ig-superfamily that have Ig-like domains. Furthermore, it had a strong mitogenic effect on lymphocytes, and also caused about 3-fold of phagocytosis by macrophages within 24 hr after its addition. 相似文献
9.
Synonymous substitution rates in mitochondrial and nuclear genes of Drosophila were compared. To make accurate comparisons, we considered the following: (1) relative synonymous rates, which do not require
divergence time estimates, should be used; (2) methods estimating divergence should take into account base composition; (3)
only very closely related species should be used to avoid effects of saturation; (4) the heterogeneity of rates should be
examined. We modified the methods estimating synonymous substitution numbers to account for base composition bias. By using
these methods, we found that mitochondrial genes have 1.7–3.4 times higher synonymous substitution rates than the fastest
nuclear genes or 4.5–9.0 times higher rates than the average nuclear genes. The average rate of synonymous transversions was
2.7 (estimated from the melanogaster species subgroup) or 2.9 (estimated from the obscura group) times higher in mitochondrial genes than in nuclear genes. Synonymous transversions in mitochondrial genes occurred
at an approximately equivalent rate to those in the fastest nuclear genes. This last result is not consistent with the hypothesis
that the difference in turnover rates between mitochondrial and nuclear genomes is the major factor determining higher synonymous
substitution rates in mtDNA. We conclude that the difference in synonymous substitution rates is due to a combination of two
factors: a higher transitional mutation rate in mtDNA and constraints on nuclear genes due to selection for codon usage.
Received: 27 November 1996 / Accepted: 8 May 1997 相似文献
10.