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81.
Three-dimensional structure of the adenovirus major coat protein hexon 总被引:19,自引:0,他引:19
The three-dimensional crystal structure of the adenovirus major coat protein is presented. Adenovirus type 2 hexon, at 967 residues, is now the longest polypeptide whose structure has been determined crystallographically. Taken with our model for hexon packing, which positions the 240 trimeric hexons in the capsid, the structure defines 60% of the protein within the 150 X 10(6) dalton virion. The assembly provides the first details of a DNA-containing animal virus that is 20 times larger than the spherical RNA viruses previously described. Unexpectedly, the hexon subunit contains two similar beta-barrels whose topology is identical to those of the spherical RNA viruses, but whose architectural role in adenovirus is very different. The hexon structure reveals several distinctive features related to its function as a stable protective coat, and shows that the type-specific immunological determinants are restricted to the virion surface. 相似文献
82.
Albee AL Burnett DS Chodos AA Eugster OJ Huneke JC Papanastassiou DA Podosek FA Russ GP Sanz HG Tera F Wasserburg GJ 《Science (New York, N.Y.)》1970,167(3918):463-466
The (87)Rb-(87)Sr internal isochrons for five rocks yield an age of 3.65 +/-0.05 x 10(9) years which presumably dates the formation of the Sea of Tranquillity. Potassium-argon ages are consistent with this result. The soil has a model age of 4.5 x10(9) years, which is best regarded as the time of initial differentiation of the lunar crust. A peculiar rock fragment from the soil gave a model age of 4.44 x 10(9) years. Relative abundances of alkalis do not suggest differential volatilization. The irradiation history of lunar rocks is inferred from isotopic measurements of gadolinium, vanadium, and cosmogenic rare gases. Spallation xenon spectra exhibit a high and variable (131)Xe/(126)Xe ratio. No evidence for (129)I was found. The isotopic composition of solar-wind xenon is distinct from that of the atmosphere and of the average for carbonaceous chondrites, but the krypton composition appears similar to average carbonaceous chondrite krypton. 相似文献
83.
Summary One tonne boxes of seed potatoes cv. Désirée contaminated withErwinia carotovora were held in four different types of farm stores. In general, contamination fell rapidly immediately after harvest and rose
later in the storage season. The extent of these changes varied considerably with store type. The greatest reduction was from
a log count of 5.5 to 2.1 after one month storage, followed by a rise to 5.1 prior to planting. No relationship was found
between store temperature, relative humidity and change in contamination. There was some evidence that reduction in contamination
was related to duration of ventilation, and rise in contamination to onset of sprouting. A sample held at a constant 4°C showed
little reduction in contamination, and no rise occurred later in the storage season. 相似文献
84.
JC Jacob EL Gastal MO Gastal GR Carvalho MA Beg OJ Ginther 《Reproduction in domestic animals》2009,44(1):92-99
Data were collected daily from 23 mares during two consecutive interovulatory intervals (IOIs). Several significant (p < 0.05) new observations on temporal relationships were made. The FSH increase that begins before ovulation temporarily plateaued on the day of discharge of follicular fluid into the peritoneal cavity in association with ovulation. During the declining portion of the pre-ovulatory oestradiol surge, an abrupt reduction in the rate of decrease occurred in synchrony with the peak of the LH surge and is consistent with a negative effect of LH on oestradiol. Repeatability within mares was based on the following positive and significant correlations between the two IOIs: (i) length of the interval between ovulations and between ovulation and the beginning of follicle deviation; (ii) diameter of the pre-ovulatory follicle on days -3 to -1; (iii) number of follicles in diameter classes of 2–5 mm (correlation for 22/23 days of the IOI), 5.1–10 mm (18/23 days), 10.1–15 mm (12/23 days) and 15.1–20 mm (12/23 days) and (iv) concentrations of FSH (18/23 days) and LH (22/23 days). The greatest repeatability for the follicle-diameter classes occurred in the 2–5 mm class, and thereafter the repeatability progressively decreased as the diameters for the classes increased. Results demonstrated measurable repeatability within mares for several end points between consecutive IOIs. 相似文献
85.
86.
AIM: To investigate growth responses of cobalt-deficient lambs to increasing doses of microencapsulated vitamin B12, and to measure associated changes in serum and liver vitamin B12 concentrations over 243 days. METHODS: From a flock grazing pastures that had low cobalt (Co) levels (about 0.06 mg Co/kg dry matter), 4-6-week-old lambs (n=137) were assigned to four groups and received either no treatment or a subcutaneous injection of 3.0, 4.5 or 6.0 mg of microencapsulated vitamin B12 on Day 1. At approximately monthly intervals, all lambs were weighed and blood samples were collected from a selection (n=10) of monitor animals, up to Day 243. Liver biopsies were also carried out on the monitor lambs (n=8) on Days 1, 124 and 215. RESULTS: The vitamin B12-treated lambs grew significantly faster (p<0.001) than untreated animals. Liveweights after 243 days were 28, 45, 45 and 47 kg for the untreated, 3.0, 4.5 and 6.0 mg vitamin B12-treated lambs, respectively. Of the initial group of untreated lambs, 68% had to be removed before the end of the trial because of substantial weight loss, but none of the treated animals were similarly afflicted. Serum vitamin B12 concentrations increased in all vitamin B12-treated lambs, reaching a peak at Day 25, and those of the 4.5 and 6.0 mg vitamin B12-treated lambs remained significantly higher (except at Day 124) than the untreated lambs to Day 187. However, at Day 124, but not Day 215, the liver vitamin B12 concentrations of treated lambs were two to three times higher than those of controls. CONCLUSIONS: The growth rates of Co-deficient lambs were markedly improved by injection of 3.0, 4.5 or 6.0 mg of microencapsulated vitamin B12, and liveweights were maintained for at least 243 days. Serum vitamin B12 concentrations were related to this growth response; concentrations of <220 pmol vitamin B12/l were associated with a 95% probability that lambs were Co-deficient and would thus respond to Co/vitamin B12 supplementation. Based on these data, the current New Zealand reference criteria for Co deficiency should be reviewed. CLINICAL SIGNIFICANCE: An injection of 3 mg microencapsulated vitamin B122 given to lambs at tailing will treat Co deficiency and will increase and maintain liveweights in a flock for up to 8 months. 相似文献
87.
G H Turnwald R D Pechman J R Turk T N Hribernik H U Cox D R Waldron A Roy L Burnett E Smith 《Journal of the American Veterinary Medical Association》1988,192(1):64-66
Pneumonia caused by Mycobacterium fortuitum was diagnosed in the left lung lobes of a 3-year-old male Samoyed. Unilateral pneumonectomy and antibiotic treatment (primarily amoxicillin trihydrate-clavulanate potassium and kanamycin) were associated with resolution of the pneumonia. In dogs, M fortuitum causes pulmonary disease that radiographically resembles bacterial pneumonia. Therefore, M fortuitum infection should be considered in dogs with radiographic signs of bronchopneumonia that worsen despite antibiotic treatment. 相似文献
88.
Adsorbed protein secondary and tertiary structures by circular dichroism and infrared spectroscopy with refractive index matched emulsions 总被引:1,自引:0,他引:1
Husband FA Garrood MJ Mackie AR Burnett GR Wilde PJ 《Journal of agricultural and food chemistry》2001,49(2):859-866
The secondary structure of protein adsorbed at the emulsion interface has been studied in refractive index matched emulsions using the techniques of circular dichroism (CD) and Fourier transform infrared spectroscopy. Bovine serum albumin (BSA) and bovine beta-lactoglobulin (betalg) stabilized emulsions were studied, and the refractive index was altered by the addition of glycerol or polyethylene glycol. The effect of additive on the solution and adsorbed protein structure in addition to the effect of adsorption time was considered. Both adsorption and glycerol addition alter protein secondary structure; however, the majority of secondary structure remains. Small changes are observed in the secondary structure of adsorbed protein with time. Near-ultraviolet CD studies showed the effect of glycerol and adsorption on the aromatic groups. BSA showed small changes both upon the addition of glycerol to protein in solution and upon adsorption. betalg showed slightly larger changes upon the addition of glycerol to protein in solution and a larger change upon adsorption. 相似文献
89.
Quadrivalent pairing was observed by electron microscopy of the synaptonemal complex in pachytene spermatocytes in seven out of nine F1 Brahman × Hereford hybrid bulls. The presence of this chromosomal abnormality indicates that the carrier bulls were heterozygous for a reciprocal translocation, which could be contributing to the fertility problems of these hybrid cattle. 相似文献
90.