This paper deals with processing of multichannel remote sensing images for which it is difficult and often impossible to carry out any stage of data processing in an interactive manner and, thus, ...full or, at least, partial automation is needed. Despite of existence of many methods, it is difficult to choose the best or an appropriate one and/or to set its parameters. One reason is that quantitative criteria characterizing efficiency of applicable methods are often unknown, especially for remote sensing data at hand. Thus, it is desirable to have some preliminary prediction of errors or accuracy for data processing methods and to choose a good method and its parameters properly. Here we consider few approaches and describe the results already obtained in recent years.
The mechanism of silencing of testis expressed X-linked Stellate repeats by homologous Y-linked Suppressor of Stellate Su(Ste) repeats localized in the crystal locus was studied. The double stranded ...RNA as a product of symmetrical transcription of Su(Ste) repeat and small interference Su(Ste) siRNA were revealed suggesting the mechanism of RNA interference (RNAi) for Stellate silencing. The relief of Stellate silencing as a result of impaired complementarity between the sequences of putative target Stellate transcripts and Su(Ste) repeats was shown. The role of RNAi mechanism in the silencing of heterochromatic retrotransposon GATE inserted in Stellate cluster was revealed. The studies of cis-effects of Stellate tandem repeats causing variegated expression of juxtaposed reporter genes were extended and the lacZ variegation in imaginal disc was shown. The exceptional case of a non-variegated expression of mini-white gene juxtaposed to Stellate repeats in a construct inserted into the 39C region was shown to be accompanied by trans-activation in homozygous state. Trans-activation effect was retained after transposition of this construct into heterochromatic environment in spite of strong variegation of a mini-white gene.
Structural and functional properties of recombinant IL-4δ2, a naturally occurring splice variant of human IL-4 with a deletion of the loop region 22−37, have been analyzed. IL-4δ2 has α-helical ...structure and most likely preserves the “up−up−down−down” topology typical of the four-helix-bundle cytokines. IL-4δ2 interacts specifically with the α chain of IL-4R and competes effectively with IL-4 for the common binding sites. Thus, IL-4δ2 may act as a regulator of the cytokine net, being the natural antagonist of IL-4. Keywords: interleukin 4 • interleukine receptor • splice variant • cytokine • four-helix-bundle cytokine
The structures of krypton and xenon single crystals have been determined by X-ray diffraction at low temperatures. Both noble gases were crystallized by in situ crystallization techniques and found ...in a face-centered cubic (fcc) type structure. The electron density was reconstructed in both crystals from the X-ray structure amplitudes. It was calculated by full-potential LAPW method at the experimental geometry. A topological electron density analysis and the deformation electron density maps have shown that both Kr and Xe atoms are contracted in the solid state relative to the free atoms and are slightly aspherically polarized to each other, with bridges directed along atom−atom lines. The critical point characteristics indicate the closed-shell interactions in both crystals.
The decapeptide H
2N-Ser-Leu-Thr-Cys-Leu-Val-Lys-Gly-Phe-Tyr-COOH (termed immunorphin) corresponding to the sequence 364–373 of the CH
3 domain of the human immunoglobulin G1 Eu heavy chain and ...displaying a 43% identity with the antigenic determinant of β-endorphin was synthesized. Immunorphin was found to compete with
125I-β-endorphin for high-affinity receptors on murine peritoneal macrophages (
K = 2.5 ± 0.9 × 10
−9 M) and with
3H-morphin for receptors on murine thymocytes (
K
i = 2.7 ± 0.6 × 10
−9 M) and murine macrophages (
K
i = 5.9 ± 0.7 × 10
−9M). In particular two types of receptors to
125I-β-endorphin with
K
d1 = 6.1 ± 0.6 × 10
−9 M and
K
d2 = 3.1 ± 0.2 × 10
−8 M were revealed on macrophages. The second type of receptors interacted with
125I-β-endorphin,
3H-Met-enkephalin,
3H-Leu-enkephalin and
3H-morphin; the first displayed reactivity with
125I-β-endorphin,
3H-morphin and immunorphin. The first type receptors are not present on murine brain cells nor are inhibited by naloxone. A minimum fragment of immunorphin practically completely retaining its inhibitory activity in the competition tests with
125I-β-endorphin for common receptors on thymocytes was found to correspond to the tetrapeptide H
2N-Lys-Gly-Phe-Tyr-COOH (
K
i = 5.6 ± 0.5 × 10
−9 M).
Structural and functional properties of recombinant IL-4delta2, a naturally occurring splice variant of human IL-4 with a deletion of the loop region 22-37, have been analyzed. IL-4delta2 has ...alpha-helical structure and most likely preserves the "up-up-down-down" topology typical of the four-helix-bundle cytokines. IL-4delta2 interacts specifically with the alpha chain of IL-4R and competes effectively with IL-4 for the common binding sites. Thus, IL-4delta2 may act as a regulator of the cytokine net, being the natural antagonist of IL-4.
We have cloned and sequenced the Fc-receptor-encoding gene, fcrV, from a group G streptococcus. Considerable similarity was revealed between the FcRV, FcRA76 and M proteins of group A streptococci in ...their signal sequences and 3' termini, and between the Fc-binding regions of FcRV and FcRA76. The promoter and terminator regions showed no homology with those of the fcrA76 and M protein-encoding genes. The A1-A4 domains of FcrV (protein V) exhibit a heptapeptide repeat motif which is characteristic of alpha-helical coiled-coil proteins. The sequence, Ser-Asn-Arg-Ala-Ala, in the outer position, 'f' of each domain is highly conserved and may be involved in FcR-IgG interactions.
Pig antibodies to the dinitrophenyl group and fragments derived from them by limited proteolysis were studied by temperature-perturbation and solvent-perturbation spectroscopy with particular ...attention to differences between the number of perturbed chromophores in free antibodies and in antibody-hapten complexes. The position of the maxima in the difference spectra show that solvent-perturbed chromophores are exposed to water, but thermally perturbed chromophores are located in a microenvironment the polarity of which corresponds to 25-50% ethylene glycol. A significant fraction of tyrosine residues (65-90%) and tryptophan residues (20-45%) is perturbed by temperature. Much lower fractions, i.e. 35-45% of tyrosine residues and less than 15% of tryptophan residues, are perturbed by 20% glycerol. The numbers of perturbed chromophores in fragments constituting the molecule are lower than or equal to the numbers in the original molecule. The effect of hapten binding is significant only with one of the antibody types, the precipitating antibody. The number of thermally perturbed tyrosine residues is by about 17% lower in the liganded antibody. The absence of an analogous effect in the Fab fragment suggests that the fine conformational mechanism of signal transfer from the binding sites operates only in intact antibody molecules.
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