Formation of a Tree having a Low Lignin Content

Received 30 September 2001/ Accepted in revised form 26 October 2001     

Expression of adrenocorticotropin-releasing hormone precursor gene in placenta and other nonhypothalamic tissues in man

Adrenocorticotropin-releasing hormone (CRH) is a peptide originally isolated from the hypothalamus. Immunocytochemical and RIA studies have revealed that CRH-like peptide is also localized in human nonhypothalamic tissues and some tumors. To see if CRH is synthesized in these nonhypothalamic tissues and tumors, we examined preproCRH mRNA in these tissues by Northern blot analysis using a cloned human preproCRH gene as a probe. PreproCRH mRNA was detected in human hypothalamus, cerebral cortex, adrenal gland, placenta, pheochromocytoma, and thymic carcinoid. The content of preproCRH mRNA in placenta was apparently greater than that in the whole hypothalamus.     

p-nitrophenyl penta-N-acetyl-beta-chitopentaoside as a novel synthetic substrate for the colorimetric assay of lysozyme

p-Nitrophenyl beta-glycosides of N-acetylchitooligosaccharides (PNP-(GlcNAc)n n = 3-5) were examined as substrates for lysozyme [EC 3.2.1.17]. The enzyme released predominantly p-nitrophenyl N-acetyl-beta-D-glucosaminide (PNP-GlcNAc) from each substrate. Furthermore, the initial rate of PNP-GlcNAc formation in lysozyme-catalyzed hydrolysis of p-nitrophenyl penta-N-acetyl-beta-chitopentaoside (PNP-(GlcNAc)5) was about 350 and 25 times faster than those of p-nitrophenyl tri-N-acetyl-beta-chitotrioside (PNP-(GlcNAc)3) and p-nitrophenyl tetra-N-acetyl-beta-chitotetraoside (PNP-(GlcNAc)4), respectively. From these results, a new colorimetric assay method of lysozyme using PNP-(GlcNAc)5 as a substrate was developed on the basis of the determination of p-nitrophenol liberated from the substrate by lysozyme through a coupled reaction involving beta-N-acetylhexosaminidase (NAHase). The assay system gave a linear dose-response curve in the range of 2-120 micrograms of lysozyme in a 15-60 min incubation. The present assay was not significantly influenced by the ionic strength of the medium and was reproducible. This method using PNP-(GlcNAc)5 as a substrate was shown to be useful for lysozyme assay.     

Induction of 3-Hydroxy-3-methylglutaryl CoA Reductase in Potato Tubers after Slicing, Fungal Infection or Chemical Treatment, and Some Properties of the Enzyme

Intact tubers of potato (Solanum tuberosum L. cv. Irish Cobblerand an interspecific hybrid between S. tuberosum and S. demissumcv. Rishiri) contain a very low activity of 3-hydroxy-3-methylglutaryl(HMG)-CoA reductase. The activity increased first in responseto slicing, and again in response to additional treatments suchas inoculation with an incompatible race of Phytophthora infestans,application of a hyphal wall component of the fungus or HgCl₂solution, and then decreased. Both the first and the secondincreases in activity in response to slicing and additionaltreatment with a hyphal wall component to elicit phytoalexinproduction were inhibited by blasticidin S. Properties of HMG-CoAreductase induced by slicing and by additional treatment withHgCl₂ or fungal inoculation were investigated. ² Present address: Faculty of Home Economics, Nagoya Women'sUniversity, Shioji-cho, Mizuho, Nagoya 467, Japan.     

Ultraviolet-sensitive ooplasmic factors are responsible for the development of an endoderm-specific alkaline phosphatase in the ascidian embryo

The ascidian egg contains muscle and endoderm determinants that play critical roles in the specification of muscle and endoderm cells, respectively. Endoderm cells of the ascidian embryo express alkaline phosphatase (AP) as a tissue-specific enzyme. We obtained egg fragments from the unfertilized eggs of Ciona savignyi by means of centrifugal force. The largest fragment (red fragments) contained the egg nucleus while other small fragments (black, clear and brown fragments) were anucleate. When inseminated, only red fragments developed into partial embryos, which showed only epidermis cell differentiation and, very rarely, AP activity. When red fragments were fused with other fragments, only black fragments promoted AP expression, suggesting that endoderm determinants were concentrated in the black fragments. A lower dose (1500 J/m²) of ultraviolet (UV) light did not eliminate the AP-promoting ability of black fragments, while this dose significantly repressed the ability to promote the expression of the muscle-marker. A higher dose (4500 J/m²) of UV light markedly reduced the AP-promoting activity of black fragments. These results suggest that factors for endodermal AP development are inactivated by UV irradiation, but are more resistant than muscle determinants.     

Nitric Oxide Induces Phytoalexin Accumulation in Potato Tuber Tissues

We investigated whether nitric oxide (NO) radical could inducephytoalexin production. Treatment of potato tuber tissues with1-hydroxy-2-oxo-3,3-bis(2-aminoethyl)-1-triazene (NOC-18), anNO-releasing compound, induced the accumulation of the potatophytoalexin rishitin. This induction was inhibited by carboxy-2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide(carboxy-PTIO), an NO-specific scavenger, or by Tiron, a radicalscavenger, suggesting a phytoalexin inducing activity for NO. (Received December 7, 1995; Accepted January 4, 1996)     

Antitumor effects of human recombinant interleukin-1α and etoposide against human tumor cells: mechanism for synergismin vitro and activityin vivo

Recombinant human interleukin 1α (rh IL-1α) and etoposide (VP-16) synergize for direct growth inhibition of several human tumor cell linesin vitro. Our previous studies demonstrated that VP-16 increased the number of membrane-associated IL-1 receptors (IL-1Rs) and also enhanced the internalization of receptor-bound rh IL-1α. The purposes of this study were to test our hypothess that these events were critical to the synergy between rhIL-1α and VP-16, to determine whether rhIL-1α and VP-16 synergize to increase superoxide (SO) anion radical productionin vitro since SO anion has been implicated in the toxic effects of IL-1, and to investigate the antitumor efficacy of the combinaton against tumors in vivo. A375/C6 melanoma cells and OVCAR-3 ovarian carcinoma cells were tested with IL-1 receptor antagonist (IL-1ra) before exposure to rhIL-1α, VP-16 and rhIL-1α plus VP-16. The synergistic or antagonistic effects were assessed by MTT assay. SO production was measured by reduction of cytochrome C. Athymic female mice bearing the A375/C6 melanoma were treated by rhIL-1α, VP-16, and rhIL-1α+VP-16. The antitumor effects were evaluated by quantitating tumor growth and survival time. Pretreatment with the IL-1ra abrogated the synergistic effects of rhIL-1α and VP-16. The production of SO radical by A375/C6 cells was increased 2.5 fold by the combination of rhIL-1α and VP-16, and the addition of exogenous SOD blocked the synergy between rhIL-1α and VP-16. However, when A375/S0D15 cells which over-expressed manganese superoxide dismutase (MnSOD) after MnSOD cDNA transfecton were exposed to rhIL-1α and VP-16, in vitro antagonism was observed. In vivo studies demonstrated that the combination of rhIL-1α and VP-16 delayed tumor growth better than either agent alone, although long-term survival was not improved because of substantial toxicity. Our results suggest that the synergistic antitumor effects of IL-1α and VP-16 may be due to IL-1R modulation and increased internalization of IL-1-IL-1R complex by VP-16 treatment, as well as to a subsequent increase in SO anion radical production from the tumor cells exposed to both drugs. Thus, the combnation of IL-1α and VP-16 might prove useful for the treatment of malignant diseasein vivo, if the increased toxicity can be reduced or managed. The US Government’s right to retain a non-exclusive royalty-free license on and to any copyright is acknowledged.