Dual-frequency phase conjugation wave generation with the high-order nonlinear effect by nondegenerate six-wave mixing in photorefractive Fe:LiNbO(3)

This paper demonstrates dual-frequency phase conjugation waves via the high-order nonlinear effect by nondegenerate six-wave mixing in iron-doped lithium niobate. In the experiment, two conjugation waves of different frequency are generated. Conjugation wave 1 is similar to nondegenerate four-wave mixing; conjugation wave 2 is completely different. The experiments measure the relationships between two conjugation wave intensities and parameters, respectively, and compare the differences of the two conjugation waves. To explain the experimental results, we assume that there is a fifth-order nonlinear interaction in crystal, and we believe the two conjugation waves are generated via different level nonlinear interactions. The theory agrees with the experimental results.

ATP secretion and extracellular protein phosphorylation by CNS neurons in primary culture

The significant role of secreted ATP in the regulation of neuronal function and the activity of ecto-protein kinases which utilize extracellular ATP to phosphorylate proteins localized at the cell surface have been previously studied in peripheral neurons and in cloned neural cell lines. In the present study we have utilized neostriatal neurons differentiated in primary culture to demonstrate vesicular secretion of ATP and phosphorylation of proteins by extracellular ATP in neurons derived from the central nervous system (CNS). Neostriatal neurons from embryonic mice were maintained in a chemically defined medium for 15-18 days. Functional differentiation was determined by measuring evoked GABA-release. ATP-secretion was measured by luciferin-luciferase assays, and protein phosphorylation by adding gamma-32P-ATP to the extracellular medium. Depolarization by 50 mM KCl induced a Ca++-dependent ATP release, and stimulation by 100 microM veratridine resulted in secretion of ATP that could be blocked by tetrodotoxin. Phosphorylation of specific protein components with apparent molecular mass of 110 Kd, 80 Kd, 55 Kd, 30 Kd and 20 Kd was detected in striatal neurons incubated for 15 min with gamma-32P-ATP added to the medium, but not by labeling intracellular ATP pools with equivalent amounts of radioactivity presented as inorganic 32Pi. These results open for investigation the role of extracellular protein phosphorylation systems in processes underlying the responsiveness of CNS neurons to secreted ATP.

B cell memory to thymus-independent antigens type 1 and type 2: the role of lipopolysaccharide in B memory induction

Several studies have indicated that thymus-independent (TI) antigens, unlike their thymus-dependent (TD) counterparts, are poor at generating memory antibody responses (Immunol. Today 1981. 3:217). In contrast to this view, the present report shows that the TI type 1 (TI-1) antigen, 2,4,6-trinitrophenyl-lipopolysaccharide (TNP-LPS), elicits good secondary responses in rats. These secondary antibody responses are not only greater in magnitude than the primary responses, but display a different pattern of Ig classes with more IgG and IgA antibodies produced. In transfer experiments between congenic strains of rats which differ in their kappa light chain Ig allotype, it is shown that this memory is attributable to persistent B cell clones. The TI-2 antigen, 2,4-dinitrophenyl-hydroxyethyl starch (DNP-HES), given alone did not elicit B cell memory. However, when DNP-HES is presented to the immune system in association with LPS, the pattern of the anti-DNP response is similar to that elicited by TNP-LPS. The capacity to generate TI memory is associated with the appearance of hapten-specific B cells in the marginal zones of the spleen. Hapten-binding cells were induced in the marginal zones following immunization with TNP-LPS, but not by DNP-HES. However, concurrent immunization with DNP-HES and LPS which were not covalently linked was found to induce DNP-binding cells in the marginal zone. There is complete correlation between the appearance of hapten-binding memory B cells in the marginal zone and the capacity of these antigens to induce secondary responses.

Is rapid proliferation in B centroblasts linked to somatic mutation in memory B cell clones?

Antigen-reactive B cells accumulate mutations in the variable (v) regions of their immunoglobulin genes during certain phases of T cell-dependent (TD) antibody responses. This is associated with a rise in the affinity of specific antibody. The time when somatic mutations are accumulating seems to coincide with the presence of germinal centres. This has led to the suggestion that a mechanism leading to a high rate of base pair substitution in immunoglobulin v region genes might operate in centroblasts in germinal centres. The rate of accumulation of mutations in v region genes is likely to relate to the number of specific B cells in cycle and their rate of cell division. The present report provides evidence pointing to centroblasts having a remarkably short cell cycle time of some 6 to 7 hours. This rapid rate of proliferation may explain the clonal expansion which occurs in the early phase of TD antibody responses and the efficiency with which high affinity mutants are subsequently selected.

Alterations in lipid composition and fluidity of liver plasma membranes in copper-deficient rats

In view of the importance of membrane fluidity on cell functions, the influence of phospholipid acyl groups on membrane fluidity, and the changes in lipid metabolism induced by copper (Cu) deficiency, this study was designed to examine the influence of dietary Cu on the lipid composition and fluidity of liver plasma membranes. Male Sprague-Dawley rats were divided into two dietary treatments, namely Cu deficient and Cu adequate. After 8 weeks of treatment, liver plasma membranes were isolated by sucrose density gradient centrifugation. The lipid fluidity of plasma membranes, as assessed by the intramolecular eximer fluorescence of 1,3-di(1-pyrenyl) propane, was significantly depressed by Cu deficiency. In addition, Cu deficiency significantly reduced the content of arachidonic and palmitoleic acids but increased the docosatetraenoic and docosahexaenoic acids of membrane phospholipids. This alteration in unsaturated phospholipid fatty acid composition, especially the large reduction in arachidonic acid, may have contributed to the depressed membrane fluidity. Furthermore, Cu deficiency also markedly altered the fatty acid composition of the triacylglycerols associated with the plasma membranes. Thus, the lipid composition and fluidity of liver plasma membranes are responsive to the animal's Cu status.

Frequency-varied conjugation wave generation via nondegenerate four-wave mixing in Fe:LiNbO(3) crystal

This paper demonstrates the frequency-varied conjugation wave generation via nondegenerate four-wave mixing in photorefractive iron-doped lithium niobate crystal. The experiment uses 4880- and 6328-A laser beams as mixing waves. The results are different from nearly degenerate four-wave mixing. The conjugation wave intensity depends on many parameters.

Orally administered kappa as well as mu opiate agonists delay gastrointestinal transit time in the guinea pig

When an orally administered opiate agonist is systemically bioavailable, the relative activity of that opioid in delaying gastrointestinal transit (GIT) depends on its relative action at central and peripheral sites. This in turn depends on the density of opioid receptor specific subtypes at those sites of action in the species under study. In rats the kappa selective agonist U-50,488H has no effect on GIT. We have found that this same agonist is equipotent to mu agonists morphine and 1-methadone in delaying the orocecal transit of a charcoal meal when administered orally to guinea pigs. Thus, both kappa as well as mu receptor subtypes are involved in the mechanisms of opiate induced slowing of GIT in the guinea pig in contrast to the rat. Interspecies differences must be considered when determining the contribution of opiate receptor subtypes to the mechanisms of opiate-induced constipation.

The relationship between Hb Bart's levels in cord blood and the deletions of alpha-globin genes

A relationship between Hb Bart's levels in cord blood and the number of alpha-globin genes has been established by screening cord blood samples from 1,075 newborn babies. Diagnosis was made by gene mapping of DNA samples with restriction endonuclease digestion. The presence of Hb Bart's was determined with a discontinuous microelectrophoresis on cellulose acetate at pH 8.34. The establishment of this relationship allows an early diagnosis of alpha-thalassemia by this simple microelectrophoretic procedure.

Mapping of rat prostatic binding protein genes C1, C2, and C3 to rat chromosome 5 by in situ hybridization

Rat prostatic binding protein genes C1, C2, and C3 were mapped on rat chromosome 5 by in situ hybridization on rat peripheral blood chromosome preparations using three different cDNA probes. Of the grains detected, 15.9%, 25.2%, and 19.6%, respectively, mapped to chromosome 5. For each probe, the label was predominantly located on 5q31, but for C2 and C3 an additional site on 5q21 was found. The results suggest that three genes coding for the different polypeptide chains of rat prostatic binding protein map to the same chromosome and presumably to the same chromosome band.

Optical sine transformation

The phase mask distribution of optical sine transformation (OST) has been calculated according to the optical general transformation theory. To avoid the diffraction loss of the phase mask, the optical waveguide method is used. Computation shows that the optical sine transformation is possible with only one phase mask, i.e., one-half of a cylindrical lens in the 1-D case and one-quarter of a spherical lens in the 2-D case. Experimental results agree with the theoretical prediction. Image compression by OST is also given.

The transforming protein of avian reticuloendotheliosis virus is a soluble cytoplasmic protein which is associated with a protein kinase activity

We have identified the product (p57v-rel) of the transforming gene, v-rel, of avian reticuloendotheliosis virus (REV-T) using antisera generated against nonoverlapping sequences representing the middle and carboxy-terminal regions of the v-rel protein expressed in Escherichia coli (N.K. Herzog and H.R. Bose, Jr., 1986, Proc. Natl. Acad. Sci. USA 83, 812-816). The amino-terminal region of the v-rel protein was also expressed in E. coli and used to generate antisera. The immunoglobulin-enriched fractions of these antisera were used to determine the subcellular location of p57v-rel in REV-T transformed lymphoid cells. Cells were fractionated into nuclear, mitochondrial, microsomal, and cytoplasmic fractions. The majority of p57v-rel was found in the cytoplasm. Examination of REV-T transformed lymphoid cells labeled with 32Pi revealed that the majority of the phosphorylated form of the v-rel protein was also found in the cytoplasm. Indirect immunofluorescence of REV-T transformed cells gave a diffuse cytoplasmic pattern indicating that p57v-rel was not associated with any discrete cellular organelle. The distribution of p57v-rel was similar in REV-T transformed lymphoid cells labeled with [35S]methionine for short and long periods of time, suggesting that p57v-rel is a soluble cytoplasmic protein throughout its lifetime. The v-rel protein was phosphorylated when immune complexes precipitated from transformed cells with the immunoglobulin fractions obtained from antisera against the amino-terminal, middle, and carboxy-terminal regions of v-rel were incubated with [gamma-32P]ATP and Mn2+. The phosphorylation of p57v-rel in the in vitro immune complex kinase assay was inhibited when the immunoglobulin-enriched fraction of these antisera was preincubated with the homologous v-rel fusion proteins. Preincubation with heterologous proteins did not block the phosphorylation of p57v-rel. These observations suggest that p57v-rel is associated with a protein kinase activity. Most of the kinase activity was found in the soluble cytoplasmic fraction of transformed cells. The transforming protein encoded by v-rel is a relatively stable protein with a half-life of approximately 7 to 8 hr in transformed lymphoid cells.