Elucidation of the structure of a possible intermediate in chlorogenic acid biosynthesis in sweet potato root tissue

The structure of a possible intermediate, compound V, in chlorogenicacid biosynthesis in sweet potato root tissue was determinedas ß-1-cinnamoyl-D-glucose. The role of the compoundin chlorogenic acid biosynthesis is also discussed. ¹ This paper constitutes Part 101 of the Phytopathological Chemistryof Sweet Potato with Black Rot and Injury. (Received June 28, 1972; )     

Transient Gene Expression in Plant Cells Mediated by Agrobacterium tumefaciens: Application for the Analysis of Virulence Loci

A simple system is described for detection of the transfer ofT-DNA from Agrobacterium cells to suspension-cultured tobaccoBY-2 cells. A modified reporter gene for rß-glucuronidase(GUS) that contained an intron sequence was introduced intothe T-DNA region such that the GUS protein could be synthesizedin plant cells only after transfer of the T-DNA to plant nuclei.When BY-2 cells were co-cultured with Agrobacterium cells thatcontained the modified reporter gene, transient synthesis ofGUS protein was observed between 36 and 48 h after the onsetof co-culture. The level of GUS activity reached a plateau withinas little as 48 h. This temporal profile of GUS activation suggeststhat the transient activity might have been due to expressionof the GUS gene in the T-DNA that had been transferred to theplant nuclei but had not yet been integrated into the plantchromosomes. Levels of transient GUS activity were also examinedwith various vir mutants of Agrobacterium and in a mutant withan altered chromosomal acvB gene, the gene for a protein thathas been postulated to function outside bacterial cells. Duringco-culture with virB, virD2, virD4 and acvB mutants, GUS activityremained at background levels, and the GUS activity in the caseof the virE2 mutant was thirty-fold lower than with the wildtype. On the basis of these results, we discuss the roles ofthese genes during infection by Agrobacterium of plant cells. ⁴Present address: Biochemistry Laboratory, Kanebo Ltd., 5-3-28Kotobuki-cho, Odawara, Kanagawa, 250 Japan     

Intracellular transport of cholesteryl esters from lysosomes to cytoplasm in macrophages

The mechanism through which nonmembranous lipid inclusion bodies consisting of cholesteryl esters accumulate in the cytoplasm was studied. Most lipid inclusion bodies in macrophages after 24 h incubation with anisotropic cholesteryl oleate liquid crystals were surrounded by a limiting membrane. The limiting membrane, however, could not be observed after further incubation for 48 h in the presence of esterastin, which is known to be an inhibitor of lipase and esterase. Under these conditions, the levels of hydrolysis and re-esterification of cholesteryl esters were less than 15% and 5% of the control ones, respectively. These results suggest that the inclusion bodies were transferred from lysosomes to the cytoplasm, with partial hydrolysis of cholesteryl esters, in addition to through the pathway via microsomes.     

Production and properties of antisera to dexamethasone–protein conjugates (Short Communication)

Antibodies to dexamethasone 21-hemisuccinate conjugated to bovine serum albumin were produced in rabbits. Antisera diluted 1:3000 bound 50% of 90pg of [1,2-(3)H]dexamethasone. The cross-reaction of the antisera with other synthetic and natural corticosteroids was measured.     

Telomere shortening in human HL60 cells by treatment with 3'-azido-2',3'-dideoxynucleosides and telomerase inhibition by their 5'-triphosphates

Telomerase is thought to play an important role in the mechanism of tumor cell immortalization by maintenance of telomere length. To obtain information on the susceptibility of telomerase to nucleoside analogues, the effects of base-modified 3'-azido-2',3'-dideoxynucleoside triphosphates on the enzyme were investigated. It is suggested that the 2-amino group of the nucleotide purine nucleus is important for the inhibitory activity. Telomere shortening caused by long-term treatment with these nucleosides is also described.     

Homologs of the sexually induced gene 1 (sig1) product constitute the stramenopile mastigonemes

The tripartite tubular mastigoneme on the anterior flagellum is a morphological feature that characterizes the stramenopiles. Mastigonemes are significant and potentially informative structures not only from the viewpoint of systematics, but also of cell biology. Nevertheless, few biochemical studies have been reported on stramenopile mastigonemes. The flagella of Scytosiphon lomentaria (Phaeophyceae) were successfully isolated and analyzed using SDS-PAGE followed by protein sequencing. The partial amino acid sequence of one flagellar protein (115kDa) showed high similarity with the sexually induced gene 1 (sig1) product of centric diatoms. A polyclonal antibody against the 115-kDa protein reacted not only to the shaft of mastigonemes in Scytosiphon lomentaria, but also another distinctly different stramenopile flagellate, Sulcochrysis biplastida (Dictyochophyceae). Therefore, we propose that the 115-kDa protein (i.e. Sig1 homologs) is a constituent of the tubular shaft of the mastigoneme.     

Structure and luminescence of sodium and lanthanide(III) coordination polymers with pyridine-2,6-dicarboxylic acid

A series of coordination polymers constructed by sodium, lanthanide(III), and pyridine-2,6-dicarboxylate (dipic),NaLn(dipic)₂ · 7H₂O (Ln = Eu, Gd, Tb), have been prepared under a hydrothermal condition. The crystal structures of the three compounds which are isostructual were determined by single-crystal X-ray diffraction. The two-dimensional layers found in the compounds are built up from six-folded {NaO₆} polyhedra and nine-folded {LnN₂O₇} polyhedra, these being edge-shared each other along the c axis and bridged by carboxylate groups of dipic along the b axis, respectively. This two-dimensional framework provides cavities inside the layer and interlayer spaces outside the layer for accommodation of the two dipic molecules coordinated to a lanthanide(III) ions. The dehydrated materials obtained by heating the as-synthesized crystals at 200 °C held their crystal structure, and absorbed the same amounts of water molecules as those of the as-synthesized crystals upon the exposure of 100% relative humidity at room temperature. The Eu and Tb compounds showed strong red and green emissions, respectively, due to an energy transfer from dipic molecules to trivalent emission ions.     

Real-time imaging of rabbit retina with retinal degeneration by using spectral-domain optical coherence tomography

Background

Recently, a transgenic rabbit with rhodopsin Pro 347 Leu mutation was generated as a model of retinitis pigmentosa (RP), which is characterized by a gradual loss of vision due to photoreceptor degeneration. The purpose of the current study is to noninvasively visualize and assess time-dependent changes in the retinal structures of a rabbit model of retinal degeneration by using speckle noise-reduced spectral-domain optical coherence tomography (SD-OCT).

Methodology/Principal Findings

Wild type (WT) and RP rabbits (aged 4–20 weeks) were investigated using SD-OCT. The total retinal thickness in RP rabbits decreased with age. The thickness of the outer nuclear layer (ONL) and between the external limiting membrane and Bruch''s membrane (ELM–BM) were reduced in RP rabbits around the visual streak, compared to WT rabbits even at 4 weeks of age, and the differences increased with age. However, inner nuclear layer (INL) thickness in RP rabbits did not differ from that of WT during the observation period. The ganglion cell complex (GCC) thickness in RP rabbits increased near the optic nerve head but not around the visual streak in the later stages of the observation period. Hyper-reflective change was widely observed in the inner segments (IS) and outer segments (OS) of the photoreceptors in the OCT images of RP rabbits. Ultrastructural findings in RP retinas included the appearance of small rhodopsin-containing vesicles scattered in the extracellular space around the photoreceptors.

Conclusions/Significance

In the current study, SD-OCT provided the pattern of photoreceptor degeneration in RP rabbits and the longitudinal changes in each retinal layer through the evaluation of identical areas over time. The time-dependent changes in the retinal structure of RP rabbits showed regional and time-stage variations. In vivo imaging of RP rabbit retinas by using SD-OCT is a powerful method for characterizing disease dynamics and for assessing the therapeutic effects of experimental interventions.