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排序方式: 共有185条查询结果,搜索用时 31 毫秒
161.
162.
N. Guillen M. H. Gabor R. D. Hotchkiss L. Hirschbein 《Molecular & general genetics : MGG》1982,185(1):69-74
Summary Nucleoids of non-complementing diploids (Ncd) from protoplast fusion of B. subtilis were isolated. Their purified DNA banded in neutral CsCl gradient as a single unimodal peak of buoyant density 1.711 g/cm3, a value which is similar to that of the DNA purified from the original parental strains, suggesting that methylation of bases is not a significant factor in chromosome inactivation. Nucleoids released from a Ncd clone give two peaks in a sucrose gradient with a characteristic S value for each nucleoid. That is in contrast to nucleoids from the haploid parents whose sedimental patterns show only one peak.Both nucleoid preparations from Ncd strains assayed for transformation activity show the fast sedimenting nucleoid devoid of transformation activity while the slow nucleoid was active in transformation for the alleles carried by the genome which is expressed in vivo. Both nucleoids of the Ncd strains are transcribed in vivo. The RNA associated with the inactive chromosome is synthesized by the RNA polymerase of the active one.This study provides evidence that inactivation of one parental genome in the Ncd strain may be related with the tertiary organization of its DNA. 相似文献
163.
S C Kline R N Hotchkiss M A Randolph A J Weiland 《Plastic and reconstructive surgery》1990,85(2):273-280
The influence of age and maturity on longitudinal skeletal growth was studied using heterotopic limb transplantation with microvascular anastomoses between syngeneic male Lewis rats of different ages. Longitudinal growth of the tibia and growth plate morphology were compared after transplantation between isochronografts (juvenile-to-juvenile and adult-to-adult), heterochronografts (juvenile-to-adult), and unoperated limbs. Four animals comprised each experimental group, except for the juvenile-to-adult heterochronograft group, which had six animals. Limbs were measured at 2-week intervals until sacrifice at 7 weeks. All transplanted limbs demonstrated significant longitudinal growth with maintenance of growth plate morphology and columnar organization. Despite being subjected to an adult hormonal environment, the juvenile tibias transplanted into adult hosts grew 12.0 +/- 1 mm--not significantly different from the unoperated juvenile controls, which grew 12.2 +/- 1 mm. Adult isochronografts showed continued growth of 3.1 mm, which was not significantly different from the unoperated control. Juvenile isochronografts demonstrated decreased growth when compared to unoperated limbs. Maintenance of growth in juvenile limbs transplanted to adults suggests a permissive effect of the hormonal milieu and that ultimate skeletal length is primarily determined by factors inherent in each physis. The use of vascularized transplantation of limbs in syngeneic animals of different ages offers a unique method of altering the hormonal and maturational milieu of the growth plate. 相似文献
164.
Vernon W. Proctor Dana G. Griffin III Arland T. Hotchkiss 《American journal of botany》1971,58(10):894-901
The series Gymnobasalia, a sharply differentiated subgeneric complex within the genus Chara, consists of at least seven morphologically distinct species. All seven species are reproductively isolated from one another. No evidence of even limited hybridization between the seven was encountered. The two dioecious members of the complex occupy restricted and, possibly partially overlapping ranges in South America. Monoecious members are in general more widely distributed but still appear to have originated in Central or South America. The holotype of C. zeylanica Klein ex Willdenow was examined and found to be tetrascutate. For the abundant and widely distributed monoecious-conjoined, octoscutate member of the complex, previously shown to be distinct from C. zeylanica, the earlier name C. haitensis Turpin is here validated. Chara foliolosa Muhl. ex Willdenow is considered conspecific with, but to hold priority over, C. sejuncta Braun. 相似文献
165.
166.
Phylogeny and expression of carbonic anhydrase-related proteins 总被引:1,自引:0,他引:1
Background
Carbonic anhydrases (CAs) are found in many organisms, in which they contribute to several important biological processes. The vertebrate α-CA family consists of 16 subfamilies, three of which (VIII, X and XI) consist of acatalytic proteins. These are named carbonic anhydrase related proteins (CARPs), and their inactivity is due to absence of one or more Zn-binding histidine residues. In this study, we analyzed and evaluated the distribution of genes encoding CARPs in different organisms using bioinformatic methods, and studied their expression in mouse tissues using immunohistochemistry and real-time quantitative PCR. 相似文献167.
Portents for a genetic engineering 总被引:4,自引:0,他引:4
R D Hotchkiss 《The Journal of heredity》1965,56(5):197-202
168.
Y J Sung J H Hotchkiss R E Austic R R Dietert 《Biochemical and biophysical research communications》1992,184(1):36-42
A simple and rapid method was applied for direct measurement of nitric oxide (NO) gas produced by cultured macrophages using a modified chemiluminescence detector, the thermal energy analyzer (TEA). HD11 chicken macrophages (1-3 x 10(6)/ml) were cultured on microcarrier beads (100 mg/ml) in 140 ml air-tight glass jars (5 ml cell suspension per jar) containing 0.5 micrograms/ml of LPS and different concentrations of L-arginine. Headspace gas was sampled at 24 hours of culture via a rubber septum and directly injected into a TEA with a liquid nitrogen trap set at -130 to -140 degrees C. The concentration of NO in the gas sample was quantified using a standard gas mixture of NO (2 microliters/L) in nitrogen. Gas samples from L-arginine-supplemented cultures contained NO (0.028-0.066 pl/microliter), whereas NO was not detected in samples from controls. These results suggest that chicken macrophages synthesize NO gas in a dose-dependent manner relative to L-arginine concentration. 相似文献
169.
Tomczyk Nathan J. Rosemond Amy D. Kominoski John S. Manning David W. P. Benstead Jonathan P. Gulis Vladislav Thomas Steven A. Hotchkiss Erin R. Helton Ashley M. 《Ecosystems》2023,26(5):1018-1032
Ecosystems - Nutrient uptake, storage, and release are critical ecosystem functions that affect carbon processing and food web dynamics. Yet, mechanisms controlling when ecosystems are net sinks or... 相似文献
170.