The Gene Encoding Flavanone 3-Hydroxylase is Expressed Normally in the Pale Yellow Flowers of the Japanese Morning Glory Carrying the speckled Mutation Which Produce Neither Flavonol nor Anthocyanin but Accumulate Chalcone, Aurone and Flavanone

The Japanese morning glory carrying the recessive mutable speckledallele with the dominant speckled-activator bears colorlessflowers with fine and round colored spots distributed over thecorolla whereas the plant without the speckled-activator producespale yellow flowers. Previous chemical analysis has indicatedthat a mutation in the gene for flavanone 3-hydroxylase (F3H)is a likely candidate for the speckled allele. However, theF3HmRNA without sequence alteration accumulates normally inthe pale yellow flowers, indicating that the speckled alleleis neither the F3H gene nor a regulatory gene acting on theF3H gene expression. (Received April 4, 1997; Accepted June 2, 1997)     

Changes in plasma thyroid hormones, luteinizing hormone (LH), estradiol, progesterone and corticosterone of laying hens during a forced molt

1. Circulating concentrations of iodothyronines, luteinizing hormone(LH), estradiol(E2), progesterone and corticosterone were measured in hens before, during, and after a forced molt induced by fasting. 2. Corticosterone increased at the onset of molt, peaked at the maximal molt and returned to pre- and post-molt levels. LH, E2 and progesterone declined during the molt, and the decline was coincident with the cessation of egg production. 3. Thyroxine(T4), triiodothyronine (T3) and reverse triiodothyronine(rT3) increased during the molt. The increases of T4 and T3 were not abolished even if the forced molt was conducted in mild weather.     

Reduction in antiviral activity of human interferon-gamma in acidic media with reference to structural change

The fluorescence intensity of a unique tryptophan 36 in human interferon-gamma was drastically decreased below pH 4 with a concomitant decrease of antiviral activity. The region of residues 32-42 of human interferon-gamma was found by calculation to have a low hydrophobicity together with a high helical hydrophobic moment, and the net electric charge of this region having an amphiphilic helical structure changed significantly near pH 4. These results suggest that the region of residues 32-42 plays an important role in exhibiting antiviral activity.     

Stage-specific localization of cytoskeletal actin mRNA in murine seminiferous tubules and intestinal epithelia as demonstrated by in-situ hybridization

Summary In-situ hybridization experiments have been performed using isoactin ( and )-specific riboprobes in various tissues of the rat and mouse. Distribution of the grains of actin mRNAs for both and types was similar throughout sections of the rat testis. Although both mRNAs were evenly distributed in the seminiferous tubule, extremely heavy labeling was observed in about 10% of the seminiferous tubules that could be identified as stage XII of spermatogenesis. At high magnification, grains of the mRNA were found in the cytoplasm of elongating spermatids and in the Sertoli cell cytoplasm at the adluminal side. Much higher density of the grains of mRNA was observed in the neck region of the spermatids at stage XII. Thus, the dense distribution of cytoskeletal actin mRNAs is stage-specific in the tubule during spermatogenesis in the rat. The high expression of both and actin mRNAs was also observed in the epithelial cells of the intestinal crypts.     

Microfibrils: a constitutive component of reticular fibers in the mouse lymph node

Summary Fibrous components other than collagen fibrils in the reticular fiber of mouse lymph node were studied by electron microscopy. Bundles of microfibrils not associated by elastin and single microfibrils dispersed among collagen fibrils were present. The diameter of the microfibrils was 13.29±2.43 nm (n=100). Elastin-associated microfibrils occurred at the periphery of the reticular fiber. Elastin was enclosed by microfibrils, thus forming the elastic fiber, which was clearly demonstrated by tannic acid-uranyl acetate staining. In the reticular fiber of lymph nodes, the elastic fiber consisted of many more microfibrils and a small amount of elastin. These microfibrils, together with the collagen fibrils, may contribut to the various functions of the reticular fibers.     

Regional distribution of DNA and RNA in rat brain: A sensitive determination using high-performance liquid chromatography with electrochemical detection

DNA and RNA contents in 20 brain regions or nuclei of the rat were determined by a highly sensitive method using high-performance liquid chromatography with electrochemical detection. The high DNA and RNA contents were found in the hypothalamic nuclei, especially the median eminence-arcuate nucleus. These results may be available for the preparation of nucleic acids as the regional control.     

Transient expression of the β-glucuronidase gene introduced into barley coleoptile cells by microinjection

A -glucuronidase gene was introduced directly into barley (Hordeum vulgare L. cv. Kobinkatagi) coleoptile cells by microinjection and transient expression of the gene was examined. Inner epidermis tissue of coleoptiles was excised and injected with plasmid DNA, pBI221, carrying cauliflower mosaic virus 35S promoter, -glucuronidase gene, and a nopaline synthase polyadenylation region. Histochemical assay for -glucuronidase production showed positive enzyme activity only in coleoptile cells injected with plasmid DNA. Expression of the -glucuronidase gene was examined chronologically using honogenates of injected coleoptile tissues. Glucuronidase activity first appeared after 6 hr, reached the maximum level 24 hr after injection, and decreased afterwards. These results suggest that microinjection of coleoptile tissues may be a useful approach for the genetic engineering of Gramineae plants in which protoplast regeneration is difficult.     

Characterization of a human immunodeficiency virus neutralizing monoclonal antibody and mapping of the neutralizing epitope.

A monoclonal antibody was produced to the exterior envelope glycoprotein (gp120) of the human T-cell lymphotropic virus (HTLV)-IIIB isolate of the human immunodeficiency virus (HIV). This antibody binds to gp120 of HTLV-IIIB and lymphadenopathy-associated virus type 1 (LAV-1) and to the surface of HTLV-IIIB- and LAV-1-infected cells, neutralizes infection by cell-free virus, and prevents fusion of virus-infected cells. In contrast, it does not bind, or weakly binds, the envelope of four heterologous HIV isolates and does not neutralize heterologous isolates HTLV-IIIRF and HTLV-IIIMN. The antibody-binding site was mapped to a 24-amino-acid segment, using recombinant and synthetic segments of HTLV-IIIB gp120. This site is within a segment of amino acid variability known to contain the major neutralizing epitopes (S. D. Putney, T. J. Matthews, W. G. Robey, D. L. Lynn, M. Robert-Guroff, W. T. Mueller, A. J. Langlois, J. Ghrayeb, S. R. Petteway, K. J. Weinhold, P. J. Fischinger, F. Wong-Staal, R. C. Gallo, and D. P. Bolognesi, Science 234:1392-1395, 1986). These results localize an epitope of HIV type-specific neutralization and suggest that neutralizing antibodies may be effective in controlling cell-associated, as well as cell-free, virus infection.     

Intranuclear microinjection for transformation of tomato callus cells

An efficient method, called the culture plate method, was devised for microinjection of foreign materials into nuclei of tomato callus cells. The culture plate method, used in this study, is advantageous because cells suitable for microinjection can be selected microscopically and the injected cells subsequently cultured in the same plate. With this microinjection system, some foreign materials were injected into nuclei of callus cells without causing detrimental effects. Kanamycin-resistant callus clones were obtained 1 month after injection from single cells whose nuclei were microinjected with a NPT II DNA fragment of the pE2KX plasmid.