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1.
Goats and some sheep synthesize a juvenile hemoglobin, Hb C (alpha 2 beta C2), at birth and produce this hemoglobin exclusively during severe anemia. Sheep that synthesize this juvenile hemoglobin are of the A haplotype. Other sheep, belonging to a separate group, the B haplotype, do not synthesize hemoglobin C and during anemia continue to produce their adult hemoglobin. To understand the basis for this difference we have determined the structural organization of the beta- globin locus of B-type sheep by constructing and isolating overlapping genomic clones. These clones have allowed us to establish the linkage map 5' epsilon I-epsilon II-psi beta I-beta B-epsilon III-epsilon IV- psi beta II-beta F3' in this haplotype. Thus, B sheep lack four genes, including the BC gene, and have only eight genes, compared with the 12 found in the goat globin locus. The goat beta-globin locus is as follows: 5' epsilon I-epsilon II-psi beta X-beta C-epsilon III-epsilon IV-psi beta Z-beta A-epsilon V-epsilon VI-psi beta Y-beta F3'. Southern blot analysis of A-type sheep reveals that these animals have a beta- globin locus similar to that of goat, i.e., 12 globin genes. Thus, the beta-globin locus of B-haplotype sheep resembles that of cows and may have retained the duplicated locus of the ancestor of cows and sheep. Alternatively, the B-sheep locus arrangement may be the result of a deletion of a four-gene set from the triplicated locus.   相似文献   
2.
Size classes of replication units in DNA from sea urchin embryos   总被引:4,自引:1,他引:3       下载免费PDF全文
Sea urchin DNA containing replication structures was isolated from two to four cell stage and blastula stage embryos, and examined by electron microscopy. In addition to the expected eye forms, we also observed molecules with large internal single-stranded gaps. Such structures were not present in DNA devoid of replicating molecules such as that isolated from sea urchin sperm. When the size of eye forms and interbubble distances between the two stages were compared, there was no detectable difference. In both stages, we observed two distinct size classes of bubbles and of interbubble distances. In the case of bubble sizes, the smaller size class was comprised of clustered microbubbles that ranged from 200 base pairs to 1 Kilobase (kb) with a mean of 432 base pairs. The large eye forms measured 1--35 kb with a mean of 6.8 kb. Interbubble distances also yielded two distinct populations, with the smaller class ranging from 400 base pairs to 2.3 kb (mean = 1.1 kb) and the larger population ranging from 2.8 to 36 kb (mean = 10.9 kb). Although other possibilities cannot be entirely excluded, the data support the contention that a substantial fraction of the larger eye-form population arises from the fusion of the clustered microbubbles.  相似文献   
3.
The fate of cadmium in soil is influenced to a great extent by microbial activity. Microorganisms were compared with abiotic soil components for their ability to sorb Cd from a liquid medium. When the same amount (on a dry weight basis) of bacterial cells (Serratia marcescens and Paracoccus sp.), clay (montmorillonite), or sand was separately incubated in 0.05 M phosphate buffer, pH 7.2, containing 10 ppm of Cd (10 μg/ml), bacterial cells removed the largest quantity of Cd. Dead cells sorbed much more Cd from the medium than live cells. A comparative study of Cd removal from the medium by seven soil bacteria and four fungi did not indicate appreciable differences. With increasing microbial biomass, the relative efficiency of 0.1 M NaOH as an extractant of sorbed Cd increased, whereas the extraction efficiency of 0.005 M DTPA (diethylenetriaminepentaacetic acid) decreased. It appeared that NaOH and DTPA extracted different chemical forms of Cd. This assumption was supported by vastly different correlation coefficients in the relative amount of Cd extracted by the two solvents.  相似文献   
4.
Calcrete aquifers from the Yilgarn region of arid central Western Australia contain an assemblage of obligate groundwater invertebrate species that are each endemic to single aquifers. Fine-scale phylogeographic and population genetic analyses of three sympatric and independently derived species of amphipod (Chiltoniidae) were carried out to determine whether there were common patterns of population genetic structure or evidence for past geographic isolation of populations within a single calcrete aquifer. Genetic diversity in amphipod mitochondrial DNA (cytochrome c oxidase subunit I gene) and allozymes were examined across a 3.5 km2 region of the Sturt Meadows calcrete, which contains a grid of 115 bore holes (=wells). Stygobiont amphipods were found to have high levels of mitochondrial haplotype diversity coupled with low nucleotide diversity. Mitochondrial phylogeographic structuring was found between haplogroups for one of the chiltoniid species, which also showed population structuring for nuclear markers. Signatures of population expansion in two of the three species, match previous findings for diving beetles at the same site, indicating that the system is dynamic. We propose isolation of populations in refugia within the calcrete, followed by expansion events, as the most likely source of intraspecific genetic diversity, due to changes in water level influencing gene flow across the calcrete.  相似文献   
5.

Background

Neointima forming after stent implantation consists of vascular smooth muscle cells (VSMCs) in 90%. Growth factors TGF-β1, PDGFB, EGF, bFGF and VEGF-A play an important role in VSMC proliferation and migration to the tunica intima after arterial wall injury. The aim of this paper was an analysis of functional polymorphisms in genes encoding TGF-β1, PDGFB, EGF, bFGF and VEGF-A in relation to in-stent restenosis (ISR).

Materials and Methods

265 patients with a stable coronary artery disease (SCAD) hospitalized in our center in the years 2007–2011 were included in the study. All patients underwent stent implantation at admission to the hospital and had another coronary angiography performed due to recurrence of the ailments or a positive result of the test assessing the coronary flow reserve. Angiographically significant ISR was defined as stenosis >50% in the stented coronary artery segment. The patients were divided into two groups–with angiographically significant ISR (n = 53) and without significant ISR (n = 212). Additionally, the assessment of late lumen loss (LLL) in vessel was performed. EGF rs4444903 polymorphism was genotyped using the PCR-RFLP method whilst rs1800470 (TGFB1), rs2285094 (PDGFB) rs308395 (bFGF) and rs699947 (VEGF-A) were determined using the TaqMan method.

Results

Angiographically significant ISR was significantly less frequently observed in the group of patients with the A/A genotype of rs1800470 polymorphism (TGFB1) versus patients with A/G and G/G genotypes. In the multivariable analysis, LLL was significantly lower in patients with the A/A genotype of rs1800470 (TGFB1) versus those with the A/G and G/G genotypes and higher in patients with the A/A genotype of the VEGF-A polymorphism versus the A/C and C/C genotypes. The C/C genotype of rs2285094 (PDGFB) was associated with greater LLL compared to C/T heterozygotes and T/T homozygotes.

Conclusions

The polymorphisms rs1800470, rs2285094 and rs6999447 of the TGFB1, PDGFB and VEGF-A genes, respectively, are associated with LLL in patients with SCAD treated by PCI with a metal stent implantation.  相似文献   
6.

Background  

Lung function is a strong predictor of cardiovascular and all-cause mortality. Previous studies suggest that alcohol exposure may be linked to impaired pulmonary function through oxidant-antioxidant mechanisms. Alcohol may be an important source of oxidants; however, wine contains several antioxidants. In this study we analyzed the relation of beverage specific alcohol intake with forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) in a random sample of 1555 residents of Western New York, USA.  相似文献   
7.
Both plant and animal cells contain high molecular weight immunophilins that bind via tetratricopeptide repeat (TPR) domains to a TPR acceptor site on the ubiquitous and essential protein chaperone hsp90. These hsp90-binding immunophilins possess the signature peptidylprolyl isomerase (PPIase) domain, but no role for their PPIase activity in protein folding has been demonstrated. From the study of glucocorticoid receptor (GR).hsp90.immunophilin complexes in mammalian cells, there is considerable evidence that both hsp90 and the FK506-binding immunophilin FKBP52 play a role in receptor movement from the cytoplasm to the nucleus. The role of FKBP52 is to target the GR.hsp90 complex to the nucleus by binding via its PPIase domain to cytoplasmic dynein, the motor protein responsible for retrograde movement along microtubules. Here, we use rabbit cytoplasmic dynein as a surrogate for the plant homologue to show that two hsp90-binding immunophilins of wheat, wFKBP73 and wFKBP77, bind to dynein. Binding to dynein is blocked by competition with a purified FKBP52 fragment comprising its PPIase domain but is not affected by the immunosuppressant drug FK506, suggesting that the PPIase domain but not PPIase activity is involved in dynein binding. The hsp90/hsp70-based chaperone system of wheat germ lysate assembles complexes between mouse GR and wheat hsp90. These receptor heterocomplexes contain wheat FKBPs, and they bind rabbit cytoplasmic dynein in a PPIase domain-specific manner. Retention by plants of the entire heterocomplex assembly machinery for linking the GR to dynein implies a fundamental role for this process in the biology of the eukaryotic cell.  相似文献   
8.
BACKGROUND: The NOGA (Biosense Webster, Markham, ON, Canada) injection catheter is an innovative navigational device that provides an ideal platform for intra-myocardial injection material. However, injection through a long (1.91 m), narrow (27G) nitinol needle could result in deterioration in the integrity and functionality of DNA. METHODS: To test this possibility, DNA in plasmid form (pcDNA3.1) containing the Lac Z transgene (250 micro l) was passed through the NOGA needle using a hand-held 1 cc syringe at a gentle hand injection pressure (43 +/- 3 PSI, 3.0 +/- 0.2 kg/cm(2)) or at maximal manual pressure (90 +/- 6 PSI, 6.3 +/- 0.4 kg/cm(2)), either once or 20 times. This DNA, compared to DNA not passed through the NOGA needle (control), was then used to transfect primary cultures of rat skin fibroblasts (FB) from Fisher 344 rats and the cells were subsequently stained for beta galactosidase (betagal). RESULTS: Transfection efficiency was significantly reduced by passing the DNA through the needle at both 43 +/- 3 PSI (78 +/- 4% of control, n = 10, P < 0.05 versus control) and 90 +/- 6 PSI (66 +/- 4 % of control, n = 10, P < 0.01 versus control, P < 0.02 versus 43 +/- 3 PSI). Passage of the DNA through the NOGA needle 20 times resulted in a transfection efficiency of only 5 +/- 1% of control (n = 20, P < 0.1 x 10(-11) versus control). Capillary Electrophoresis revealed that the reduction in transfection efficiency was due to a conformational change in the DNA from predominantly supercoiled to nicked and linearized DNA. Transfection efficiency as compared with control decreased as the concentration of the DNA solution which was passed through the needle was increased from 0.3 micro g/ micro l to 2.4 micro g/ micro l. Recovery experiments confirmed that the reduction in transfection efficiency was not due to loss of DNA by binding to the NOGA needle. CONCLUSION: These results suggest that DNA is susceptible to shear forces when injected through the NOGA needle even at nominal clinical injection pressures, suggesting that careful and controlled injections will be required to achieve optimal gene integrity and expression.  相似文献   
9.
The surface area of very low density lipoproteins (VLDL) from the serum of 15 healthy donors and the surface area of artificial lipid particles have been estimated. The artificial particles were prepared as a mixture of egg phosphatidylcholine and triolein. Two fluorescent probes - energy donor and acceptor - were placed on the surface, and Forster's nonradiative energy transfer was measured; the transfer efficiency is a function of surface area. The fluorescent probe K-68 (4-[5-(phenyloxazolyl-2)-1-pentadecyl)pyridinium) was used as a donor, and DSP-12 (dimethylamino)styryl-N-dodecylpyridinium) was used as an acceptor. The specific surface area of the artificial lipid particles was estimated to be 0.585 +/- 0.015 nm2 per phosphatidylcholine molecule, which is 15% less than in lipid bilayers. The specific area of VLDL particles was 259 +/- 65 m2 per g of total VLDL. This value is close to the specific area of low density lipoproteins (LDL), and corresponds to the area of a spherical particle 10-12 nm in radius. However, VLDL are assumed to be much larger particles as compared with LDL. Therefore, the new data of the VLDL surface area raise a problem of revision of the existing VLDL models.  相似文献   
10.
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