Transformation and plasmacytoid differentiation of EBV-infected human B lymphoblasts by ras oncogenes   总被引：7，自引：0，他引：7  

S Seremetis  G Inghirami  D Ferrero  E W Newcomb  D M Knowles  G P Dotto  R Dalla-Favera 《Science (New York, N.Y.)》1989,243(4891):660-663

The biological effects of ras oncogene activation in B cells were studied by using amphotropic retroviral vectors to introduce H- or N-ras oncogenes into human B lymphoblasts immortalized by Epstein-Barr virus. Expression of both H- and N-ras oncogenes led to malignant transformation of these cells, as shown by clonogenicity in semisolid media and tumorigenicity in immunodeficient mice. In addition, terminal differentiation into plasma cells was detectable as specific changes in morphology, immunoglobulin secretion, and cell surface antigen expression. This combined effect, promoting growth and differentiation in human lymphoblasts, represents a novel biological action of ras oncogenes and has implications for the pathogenesis of terminally differentiated B-lymphoid malignancies such as multiple myeloma.  相似文献   

Spectra, Variability, Size, and Polarization of H2O Microwave Emission Sources in the Galaxy     

Knowles SH  Mayer CH  Cheung AC  Rank DM  Townes CH 《Science (New York, N.Y.)》1969,163(3871):1055-1057

Radio spectral line radiation of water molecules at a wavelength of 1.35 centimeters has been measured from eight sources in the galaxy. The sources are less than I arc minute in diameter, have extremely high brightness temperatures, and show many spectral features. Some spectral features are slightly polarized and some have changed greatly in intensity in a few weeks time.  相似文献   

Search for an Effect of Mass on Frequency during a Close Approach of Pulsar CP 0950 to the Sun     

Sadeh D  Hollinger JP  Knowles SH  Youmans AB 《Science (New York, N.Y.)》1968,162(3856):897-898

Observations of the pulse arrival times from the pulsar CP 0950 were made during August when the line of sight to the pulsar approached within 5 degrees of the sun in order to test a suggested mass-on-frequency effect. The observations do not show evidence for the predicted effect.  相似文献   

High-accuracy ab initio rotation-vibration transitions for water     

Polyansky OL  Császár AG  Shirin SV  Zobov NF  Barletta P  Tennyson J  Schwenke DW  Knowles PJ 《Science (New York, N.Y.)》2003,299(5606):539-542

The spectrum of water vapor is of fundamental importance for a variety of processes, including the absorption and retention of sunlight in Earth's atmosphere. Therefore, there has long been an urgent need for a robust and accurate predictive model for this spectrum. In our work on the high-resolution spectrum of water, we report first-principles calculations that approach experimental accuracy. To achieve this, we performed exceptionally large electronic structure calculations and considered a variety of effects, including quantum electrodynamics, which have routinely been neglected in studies of small many-electron molecules. The high accuracy of the resulting ab initio procedure is demonstrated for the main isotopomers of water.  相似文献   

Galactic water vapor emission: further observations of variability     

Knowles SH  Mayer CH  Sullivan WT  Cheung AC 《Science (New York, N.Y.)》1969,166(3902):221-224

Recent observations of the 1.35-centimeter line emission of water vapor from galactic sources show short-term variability in the spectra of several sources. Two additional sources, Cygnus 1 and NGC 6334N, have been observed, and the spectra of W49 and VY Canis Majoris were measured over a wider range of radial velocity.  相似文献   

Panhandling as an example of the sharing of resources     

Knowles PL 《Science (New York, N.Y.)》1977,198(4319):858-858

  相似文献   

Metastatic hibernomas in transgenic mice expressing an alpha-amylase-SV40 T antigen hybrid gene   总被引：5，自引：0，他引：5  

N Fox  R Crooke  L H Hwang  U Schibler  B B Knowles  D Solter 《Science (New York, N.Y.)》1989,244(4903):460-463

Mice transgenic for a hybrid gene containing the liver promoter of the mouse amylase gene (Amy-1a) fused to the SV40 tumor antigen coding region unexpected developed malignant brown adipose tissue tumors (malignant hibernomas). Expression of the alpha-amylase gene had previously been thought to be confined to the liver parotid, and pancreas; however, analysis of white and brown adipose tissue from nontransgenic mice revealed expression of the endogenous Amy-1a gene in these tissues. Gene constructs driven by the Amy-1a liver promoter thus provide a means of targeting gene expression to the adipocyte cell lineage in transgenic mice. Moreover the high frequency of metastases in the liver, lungs, spleen, heart, and adrenals of these mice provides an experimental system in which to study the development of disseminated malignancy.  相似文献   

Methane production and consumption in a cultivated humisol   总被引：5，自引：0，他引：5  

S. R. Megraw  R. Knowles 《Biology and Fertility of Soils》1987,5(1):56-60

Summary Laboratory studies were conducted on a cultivated humisol containing populations of both methanotrophs and methanogens. The molar ratio CO₂ produced : O₂ consumed :CH₄ consumed was 0.27:1.0:1.0. Methane oxidation showed typical Michaelis-Menten kinetics with apparent K _m values for CH4 and O₂ of 66.2 M and 37.0 M, respectively. The low CO₂ yields and the effects of low dissolved oxygen indicated the presence of aerobic obligate methanotrophs. It is suggested that the methanotrophs in this soil are not entirely dependent on atmospheric CH₄ for growth and survival in situ.  相似文献   

Ecological-genetic investigations in environmentally stressed mature sugar maple (Acer saccharum marsh.) populations     

T H. Geburek  P. Knowles 《Water, air, and soil pollution》1992,62(3-4):261-268

In six mature, environmentally stressed sugar maple (Acer saccharum) populations totalling 350 trees, genetic structures were studied within stands. Genetic variation was electrophoretically analyzed for 12 enzyme systems. The populations revealed Hardy-Weinberg proportions for all 11 polymorphic loci. Observed and conditional heterozygosity were. 141 and 899, respectively. Analysis of fixation indices indicated a slight heterozygote deficiency compared to panmictic conditions. Population differentiation was weak (F _ST =.017). Between healthy and declining subpopulations no significant differences were detected in terms of allozyme variation. However in healthy trees, conditional heterozygosity (H _c) and relative genotypic multiplicity (M _rel) were higher in five out of six populations.  相似文献   

Studies on the role of feline calicivirus in chronic stomatitis in cats.     

J O Knowles  F McArdle  S Dawson  S D Carter  C J Gaskell  R M Gaskell 《Veterinary microbiology》1991,27(3-4):205-219

Two groups of cats were inoculated oro-nasally with one of two isolates of feline calicivirus (FCV) from clinical cases of chronic stomatitis. All cats developed signs typical of acute FCV infection; namely, ocular and nasal discharge, conjunctivitis, and marked oral ulceration. None of the cats shed virus beyond 28 days. Seronegative control cats were then infected with a lower dose of one isolate, but again only acute signs were seen and no carriers produced. The original cats were then re-infected with the heterologous isolate. As before, only signs of acute disease were seen, but the range of clinical signs and severity was reduced. Virus shedding patterns in one group were similar to those seen originally, but in the other the duration was reduced. No chronic stomatitis developed over the 10 months of the study. Serum virus neutralising and serum and salivary class specific immunoglobulin responses were investigated. Although long-term carriers were not induced, no relationship between cessation of virus shedding in an individual animal and systemic and local antibody responses was seen.  相似文献