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21.
Alpha-tocopheryl acetate, 1, 2, dihydro-6-ethoxy-2, 2, 4-trimethylquinoline, and butylated hydroxytoluene increased the number of circulating reticulocytes when added to the diet of chickens. Hematocrit values were not reduced and erythrocyte life-spans were not shortened by the antioxidants. The reticulocytosis is attributed to delayed loss of reticular material from the maturing erythrocytes. components.  相似文献   
22.
Many oomycete and fungal plant pathogens are obligate biotrophs, which extract nutrients only from living plant tissue and cannot grow apart from their hosts. Although these pathogens cause substantial crop losses, little is known about the molecular basis or evolution of obligate biotrophy. Here, we report the genome sequence of the oomycete Hyaloperonospora arabidopsidis (Hpa), an obligate biotroph and natural pathogen of Arabidopsis thaliana. In comparison with genomes of related, hemibiotrophic Phytophthora species, the Hpa genome exhibits dramatic reductions in genes encoding (i) RXLR effectors and other secreted pathogenicity proteins, (ii) enzymes for assimilation of inorganic nitrogen and sulfur, and (iii) proteins associated with zoospore formation and motility. These attributes comprise a genomic signature of evolution toward obligate biotrophy.  相似文献   
23.
The white-backed planthopper, Sogatella furcifera (Horváth) (Hemiptera: Delphacidae), is a major pest of rice and has long-range migratory behavior in Asia. Microsatellite markers (simple sequence repeats) have been widely used to determine the origins and genetic diversity of insect pests. We identified novel microsatellite loci for S. furcifera samples collected from Laos, Vietnam, and three localities in Bangladesh from next-generation Roche 454 pyrosequencing data. Size polymorphism at 12 microsatellite loci was verified for 40 adult individuals collected from Shinan, South Korea. The average number of alleles per locus was 7.92. The mean values of observed (Ho) and expected heterozygosities (HE) were 0.615 and 0.757, respectively. These new microsatellite markers will be a resource for future ecological genetic studies of S. furcifera samples across more broad geographic regions in Asia and may assist in estimations of genetic differentiation and gene flow among populations for implementation of more effective management strategies to control this serious rice pest.  相似文献   
24.
Jojoba (Simmondsia chinensis L. [Schneider]) is a wind-pollinated perennial shrub native to the Sonoran Desert. In recent years commercial plantations in Arizona and Catamarca, Argentina have dramatically decreased in size and number, going from 13,000 ha in the early 1980s to about 2,300 ha today. The main reason for this decrease is yields being lower than expected, with low pollination percentages considered the main source of the problem, although use of inferior genetic material has contributed to the problem. Artificial or supplemental pollination has been used successfully in other crops to increase yields, and it was thought that this could also be used for jojoba. A trial was carried out over two seasons in which pollen collected in Arizona, was mechanically applied to commercial fields in Catamarca. The first year yields were significantly (P < 0.05) greater in the fields in which pollen had been applied, than in the controls. The second year yields were not measured. Rather the number of capsules with fruit, aborts, and empty capsules were counted on a number of randomly selected branches. This technique gives a good estimate of yield, and the results showed that pollen application significantly (P < 0.05) increased expected yields. In conclusion, application of supplemental pollen increases jojoba yields and hence should be considered a viable option for commercial plantations. Additional work is required, however, to determine the correct application rate so as to minimize collection costs, and determine when application should take place to optimize efficacy.  相似文献   
25.
An experiment was conducted to determine whether using ruminally cannulated cattle affects the estimate of enteric methane (CH(4)) emissions when using the sulfur hexafluoride (SF(6)) tracer technique with samples taken from a head canister. Eleven beef cattle were surgically fitted with several types of ruminal cannula (2C, 3C, 3C+washer, 9C; Bar Diamond, Parma, ID). The 2C and 3C models (outer and inner flanges with opposite curvature) had medium to high leakage, whereas the 9C models (outer and inner flanges with the same curvature) provided minimum to moderate leakage of gas. A total of 48 cow-day measurements were conducted. For each animal, a permeation tube containing sulfur hexafluoride (SF(6)) was placed in the rumen, and a sample of air from around the nose and mouth was drawn through tubing into an evacuated canister (head canister). A second sample of air was collected from outside the rumen near the cannula into another canister (cannula canister). Background concentrations were also monitored. The methane (CH(4)) emission was estimated from the daily CH(4) and SF(6) concentrations in the head canister (uncorrected). The permeation SF(6) release rate was then partitioned based on the proportion of the SF(6) concentration measured in the head vs. the cannula canister. The CH(4) emissions at each site were calculated using the two release rates and the two CH(4):SF(6) concentration ratios. The head and cannula emissions were summed to obtain the total emission (corrected). The difference (corrected - uncorrected) in CH4 emission was attributed to the differences in CH(4):SF(6) ratio at the 2 exit locations. The proportions of CH(4) and SF(6) recovered at the head were greater (P < 0.001) for the 9C cannulas (64% and 66%) compared with the other cannulas, which were similar (P > 0.05; 2C, 6% and 4%; 3C, 17% and 15%; 3C+washer, 19% and 14%). Uncorrected CH(4) emissions were ± 10% of corrected emissions for 53% of the cow-day measurements. Only when more than 80% of the SF(6) escaped via the rumen did the difference between the uncorrected and corrected CH(4) emissions exceed 20%. We concluded that using cannulated cattle introduces more variability into the SF(6) technique used with a head canister, a technique that is already highly variable. Thus, use of cannulated animals is not recommended when using the SF(6) technique with head canister. However, if cannulated cattle are used, the cannulas need to be tight-fitting to minimize leakage, and large animal numbers are needed to overcome the additional variability.  相似文献   
26.
A 2-year-old, spayed female, mixed-breed dog was presented for evaluation of a progressive asymmetric tetraparesis and cranial nerve deficits with a 3-week duration. Computed tomography showed a contrast-enhancing lesion along the left side of the junction of the medulla and the cervical spinal cord. An exploratory surgery determined the presence of an intramedullary lesion of the first cervical spinal cord segment. The mass was removed through a dorsal midline myelotomy. Microscopic examination identified a foreign body granuloma that contained a dense, anisotropic outer wall, supporting the conclusion that the foreign body was of plant origin. The dog recovered to a more improved ambulatory status than prior to surgery.  相似文献   
27.
Femtosecond laser pulses and coherent two-phonon Raman scattering were used to excite KTaO3 into a squeezed state, nearly periodic in time, in which the variance of the atomic displacements dips below the standard quantum limit for half of a cycle. This nonclassical state involves a continuum of transverse acoustic modes that leads to oscillations in the refractive index associated with the frequency of a van Hove singularity in the phonon density of states.  相似文献   
28.
Angle-resolved photoemission experiments reveal evidence of an energy gap in the normal state excitation spectrum of the cuprate superconductor Bi2Sr2CaCu2O8+delta. This gap exists only in underdoped samples and closes around the doping level at which the superconducting transition temperature Tc is a maximum. The momentum dependence and magnitude of the gap closely resemble those of the dx2-y2 gap observed in the superconducting state. This observation is consistent with results from several other experimental techniques, which also indicate the presence of a gap in the normal state. Some possible theoretical explanations for this effect are reviewed.  相似文献   
29.
Five dogs with acquired myasthenia gravis (MG), verified via positive serum acetylcholine (ACh) receptor antibody concentrations, were treated with a drug protocol including azathioprine (AZA). Four of the five dogs were concurrently treated with pyridostigmine. Azathioprine was used as the sole immunosuppressive agent in four dogs. One dog was temporarily treated with a combination of an immunosuppressive dose of prednisone and AZA, then maintained on AZA as the sole immunosuppressive drug. Three patients experienced complete remission of clinical signs within three months of therapy. In the four dogs for which follow-up serum ACh receptor antibody concentrations were available, initial versus final concentrations decreased substantially (81%), coincident with clinical improvement. One dog died suddenly due to a suspected myasthenic crisis before attaining the target dose of AZA. Two of the four surviving dogs were euthanized approximately one and seven years after diagnosis. One of these two dogs was euthanized because of a rib osteosarcoma, and the other dog was euthanized because of paraparesis of undetermined cause. The remaining two dogs were alive and doing well at the time of final follow-up evaluation, approximately six months and one year after diagnosis. The use of AZA as a therapeutic agent for acquired canine MG has not been investigated. The cases presented in this report suggest a potentially important role for AZA in the treatment of acquired MG in dogs.  相似文献   
30.
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