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81.
Evidence for plasmid-associated crystal toxin production in Bacillus thuringiensis subsp. israelensis 总被引:1,自引:0,他引:1
RM Faust K Abe GA Held T Iizuka LA Bulla CL Meyers 《Canadian Metallurgical Quarterly》1983,9(1):98-103
Three crystalliferous (Cry+) strains of Bacillus thuringiensis subsp. israelensis (serotype 14) that produce parasporal protein crystals toxic to dipteran larvae and several acrystalliferous (Cry-) mutants, either induced or spontaneously derived from a single Cry+ parent, were examined for the presence of covalently closed circular (CCC) DNA in attempts to correlate toxin production with the presence of a specific plasmid. The plasmid profiles of both Cry+ and Cry- variants were analyzed by both a cleared lysate- and a modified Eckhardt lysate-electrophoresis technique. All of the Cry- mutants derived from the Cry+ parental strain had lost a 4.0- to 4.4-megadalton (Mdal) plasmid. Bioassay data confirmed loss of toxin production by the Cry- variants. All three Cry+ strains, including the parent of the Cry- strains, contained CCC plasmids DNAs of the following approximate molecular weights: 4.0 to 4.4, 5.2 to 6.0, and 11.4 to 13.0 Mdal. One Cry+ strain contained an additional CCC plasmid of 6.7 to 7.2 Mdal. The plasmid patterns for several Cry- derivatives differed in other respects from the pattern for their parent strain. The various Cry+ and Cry- strains could be distinguished either by phenotypical differences in antibiotic sensitivity, crystal production, and toxicity, or by differences in their plasmid profiles. 相似文献
82.
83.
Victor Lilly Martin Birch Bryan Garscadden 《Journal of the science of food and agriculture》1980,31(10):1059-1065
Spent brewers' or distillers' grains are normally disposed of either in the wet form, in which they spoil rapidly, or after drying, which is costly. Alternatively, the storage life of wet grains may be extended by ensiling, which involves on-farm control and equipment. This investigation examines the preservation of spent grains by lowering the water activity of the material using molasses and further stabilising the mixture by incorporating an anti-mycotic agent. Investigations at both laboratory-scale and pilot-scale are reported culminating in the successful stabilisation of the wet grains by the incorporation of 30% of beet molasses and 0.3% of potassium sorbate into the grains after preliminary centrifugation. For effective preservation the stabilised grains should be consolidated in plastic bags followed by closing to leave the minimum possible headspace in the bags. 相似文献
84.
85.
CL van Limborgh 《Canadian Metallurgical Quarterly》1980,105(3):96-105
A practitioner should be aware of the most important items regarding feed and water supply that may by a factor in assessing problems on large commercial units or in fancy breeding. A breif introduction on the function of the digestive tract precedes a discussion of the main causes of nutritional disorders which are frequently lethal. The specific mechanism of recirculation (caecotrophy) causing increased vulnerability to variations in the texture of feeds is stressed. Severe intestinal malfunction is readily induced by contaminated and spoiled feed and/or drinking water. These effects are probably underestimated in comparison with specific diseases. Data on nutritional requirements are also presented to the extent to which they are relevant in this context. 相似文献
86.
Sensitivity of the backscattering Mueller matrix to particle shape and thermodynamic phase 总被引:1,自引:0,他引:1
The Mueller matrix (M) corresponding to the phase matrix in the backscattering region (scattering angles ranging from 175 degrees to 180 degrees) is investigated for light scattering at a 0.532-microm wavelength by hexagonal ice crystals, ice spheres, and water droplets. For hexagonal ice crystals we assume three aspect ratios (plates, compact columns, and columns). It is shown that the contour patterns of the backscattering Mueller matrix elements other than M11, M44, M14, and M41 depend on particle geometry; M22 and M33 are particularly sensitive to the aspect ratio of ice crystals. The Mueller matrix for spherical ice particles is different from those for nonspherical ice particles. In addition to discriminating between spherical and nonspherical particles, the Mueller matrix may offer some insight as to cloud thermodynamic phase. The contour patterns for large ice spheres with an effective size of 100 microm are substantially different from those associated with small water droplets with an effective size of 4 microm. 相似文献
87.
SD Gettings RA Lordo KL Hintze DM Bagley PL Casterton M Chudkowski RD Curren JL Demetrulias LC Dipasquale LK Earl PI Feder CL Galli SM Glaza VC Gordon J Janus PJ Kurtz KD Marenus J Moral WJ Pape KJ Renskers LA Rheins MT Roddy MG Rozen JP Tedeschi J Zyracki 《Canadian Metallurgical Quarterly》1996,34(1):79-117
The CTFA Evaluation of Alternatives Program is an evaluation of the relationship between data from the Draize primary eye irritation test and comparable data from a selection of promising in vitro eye irritation tests. In Phase III, data from the Draize test and 41 in vitro endpoints on 25 representative surfactant-based personal care formulations were compared. As in Phase I and Phase II, regression modelling of the relationship between maximum average Draize score (MAS) and in vitro endpoint was the primary approach adopted for evaluating in vitro assay performance. The degree of confidence in prediction of MAS for a given in vitro endpoint is quantified in terms of the relative widths of prediction intervals constructed about the fitted regression curve. Prediction intervals reflect not only the error attributed to the model but also the material-specific components of variation in both the Draize and the in vitro assays. Among the in vitro assays selected for regression modeling in Phase III, the relationship between MAS and in vitro score was relatively well defined. The prediction bounds on MAS were most narrow for materials at the lower or upper end of the effective irritation range (MAS = 0-45), where variability in MAS was smallest. This, the confidence with which the MAS of surfactant-based formulations is predicted is greatest when MAS approaches zero or when MAS approaches 45 (no comment is made on prediction of MAS > 45 since extrapolation beyond the range of observed data is not possible). No single in vitro endpoint was found to exhibit relative superiority with regard to prediction of MAS. Variability associated with Draize test outcome (e.g. in MAS values) must be considered in any future comparisons of in vivo and in vitro test results if the purpose is to predict in vivo response using in vitro data. 相似文献
88.
89.
Leonard J Trejo Roman Rosipal Bryan Matthews 《IEEE transactions on neural systems and rehabilitation engineering》2006,14(2):225-229
We have developed and tested two electroencephalogram (EEG)-based brain-computer interfaces (BCI) for users to control a cursor on a computer display. Our system uses an adaptive algorithm, based on kernel partial least squares classification (KPLS), to associate patterns in multichannel EEG frequency spectra with cursor controls. Our first BCI, Target Practice, is a system for one-dimensional device control, in which participants use biofeedback to learn voluntary control of their EEG spectra. Target Practice uses a KPLS classifier to map power spectra of 62-electrode EEG signals to rightward or leftward position of a moving cursor on a computer display. Three subjects learned to control motion of a cursor on a video display in multiple blocks of 60 trials over periods of up to six weeks. The best subject's average skill in correct selection of the cursor direction grew from 58% to 88% after 13 training sessions. Target Practice also implements online control of two artifact sources: 1) removal of ocular artifact by linear subtraction of wavelet-smoothed vertical and horizontal electrooculograms (EOG) signals, 2) control of muscle artifact by inhibition of BCI training during periods of relatively high power in the 40-64 Hz band. The second BCI, Think Pointer, is a system for two-dimensional cursor control. Steady-state visual evoked potentials (SSVEP) are triggered by four flickering checkerboard stimuli located in narrow strips at each edge of the display. The user attends to one of the four beacons to initiate motion in the desired direction. The SSVEP signals are recorded from 12 electrodes located over the occipital region. A KPLS classifier is individually calibrated to map multichannel frequency bands of the SSVEP signals to right-left or up-down motion of a cursor on a computer display. The display stops moving when the user attends to a central fixation point. As for Target Practice, Think Pointer also implements wavelet-based online removal of ocular artifact; however, in Think Pointer muscle artifact is controlled via adaptive normalization of the SSVEP. Training of the classifier requires about 3 min. We have tested our system in real-time operation in three human subjects. Across subjects and sessions, control accuracy ranged from 80% to 100% correct with lags of 1-5 s for movement initiation and turning. We have also developed a realistic demonstration of our system for control of a moving map display (http://ti.arc.nasa.gov/). 相似文献
90.
Muzamil Y. Want Ellen Karasik Bryan Gillard A. J. Robert McGray Sebastiano Battaglia 《International journal of molecular sciences》2021,22(16)
Immunotherapy initially demonstrated promising results in prostate cancer (PCa), but the modest or negative results of many recent trials highlight the need to overcome the poor immunogenicity of this cancer. The design of effective therapies for PCa is challenged by the limited understanding of the interface between PCa cells and the immune system in mediating therapeutic resistance. Prompted by our recent observations that elevated WHSC1, a histone methyltransferase known to promote progression of numerous cancers, can silence antigen processing and presentation in PCa, we performed a single-cell analysis of the intratumoral immune dynamics following in vivo pharmacological inhibition of WHSC1 in mice grafted with TRAMP C2 cells. We observed an increase in cytotoxic T and NK cells accumulation and effector function, accompanied by a parallel remodeling of the myeloid compartment, as well as abundant shifts in key ligand–receptor signaling pathways highlighting changes in cell-to-cell communication driven by WHSC1 inhibition. This comprehensive profiling of both immune and molecular changes during the course of WHSC1 blockade deepens our fundamental understanding of how anti-tumor immune responses develop and can be enhanced therapeutically for PCa. 相似文献