Blue light induced inhibition of seed germination: The necessity of the fruit coats for the blue light response

The seeds (achenes) of Laportea bulbifera require a chilling to break their dormancy and are negatively photoblastic. Their germination is inhibited by both continuous blue light and continuous or prolonged far-red radiation. The germination of de-coated seeds, prepared by removing the fruit coats, however, was strongly inhibited by continuous far-red, but not by continuous blue light. Photoreversible germination by a brief irradiation with red light occurred when the chilled seeds were exposed to prolonged far-red light. These results suggest that far-red light may regulate the germination of L. bulbifera seeds through the phytochrome system which exists in the regions other than fruit coats and that the blue light reaction may be governed by other photoreceptor system(s).     

Reversion from light-induced inhibition of seed germination by respiratory inhibitors

Treating of the dark-imbibed lettuce (Lactuca sativa L.) seeds prior to light irradiation with 1 millimolar KCN or NaN₃ in the dark for 3 hours prevented blue light and far-red light-induced inhibitions of phytochrome-mediated germination. Similarly, salicylhydroxamic acid (SHAM) at 10 millimolar counteracted the blue and far-red light inhibitions, the combined application of KCN and SHAM being more effective than KCN or SHAM alone in some experiments. These respiratory inhibitors slightly inhibited phytochrome-mediated lettuce seed germination. These results indicate that both CN-sensitive, conventional cytochrome oxidase and CN-resistant (SHAM-sensitive), alternative respiration may be involved in the light inhibition or that an appropriate balance of both may be necessary for the light inhibition.     

Dormancy in Dioscorea: Generality of gibberellin-induced dormancy in asexual dormant organs

Effects of GA₃ and CCC application on the sprouting of bulbilsor subterranean dormant organs of 10 species in the genus Dioscoreawere observed. Although the efficiency of both chemicals differedby species, in general GA₃ inhibited and CCC promoted the sproutingof the above dormant organs. In some species, however, dilutedGA₃ (0.003–0.3 µM) has a promotive and diluted CCC(3–30 µM) has an inhibitive effect on sprouting. Effects of GA₃ application on shoot elongation were tested onsprouted bulbils. GA₃ promoted elongation when applied directlyto the shoots and inhibited it when applied to the bulbous parts. These results suggest that GA activates two opposing reactions—sprouting-promotingand sprouting-inhibiting—in these organs. The complicatedrelation between GA₃ or CCC concentrations and sprouting wereexplainable by assuming that the two counteractive reactionswere activated by GA in different degrees. ¹ Present address: Department of Biology, Faculty of Science,Yamagata University, Yamagata 990, Japan. (Received June 21, 1976; )     

Enzyme-amplified enzyme-linked immunosorbent assay for gibberellin A4 based on the NAD-dependent redox cycle

An antiserum against gibberellin A₄ (GA₄) raised in rabbits and its partially purified antibodies were used to develop radioimmunoassay (RIA) and indirect enzyme-linked immunosorbent assays (ELISAs) for GA₄. Of three immunoassays tested, an ELISA based on the NAD-dependent redox cycle (enzyme-amplified ELISA) had highest sensitivity. Levels of methylated GA₄ detected by this most sensitive method ranged from 0.1 fmol/assay (3.5 fg/assay) to 0.1 pmol/assay (3.5 pg/assay) suggesting applicability of this method to the detection of gibberellins in purified plant extracts.     

The RB-related gene Rb2/p130 in neuroblastoma differentiation and in B-myb promoter down-regulation

The retinoblastoma family of nuclear factors is composed of RB, the prototype of the tumour suppressor genes and of the strictly related genes p107 and Rb2/p130. The three genes code for proteins, namely pRb, p107 and pRb2/p130, that share similar structures and functions. These proteins are expressed, often simultaneously, in many cell types and are involved in the regulation of proliferation and differentiation. We determined the expression and the phosphorylation of the RB family gene products during the DMSO-induced differentiation of the N1E-115 murine neuroblastoma cells. In this system, pRb2/p130 was strongly up-regulated during mid-late differentiation stages, while, on the contrary, pRb and p107 resulted markedly decreased at late stages. Differentiating N1E-115 cells also showed a progressive decrease in B-myb levels, a proliferation-related protein whose constitutive expression inhibits neuronal differentiation. Transfection of each of the RB family genes in these cells was able, at different degrees, to induce neuronal differentiation, to inhibit [3H]thymidine incorporation and to down-regulate the activity of the B-myb promoter.     

Plasma B-type Natriuretic Peptide as a Predictor of Cardiovascular Events in Subjects with Atrial Fibrillation: A Community-Based Study

Objectives

Atrial fibrillation (AF) is a significant public health issue due to its high prevalence in the general population, and is associated with an increased risk of cardiovascular (CV) events including systemic thrombo-embolism, heart failure, and coronary artery disease. The relationship between plasma B-type natriuretic peptide (BNP) and CV risk in real world AF subjects remains unknown.

Methods

The subject of the study (n = 228; mean age = 69 years) was unselected individuals with AF in a community-based population (n = 15,394; AF prevalence rate = 1.5%). The CV event free rate within each BNP tertile was estimated, and Cox regression analysis was performed to examine the relative risk of the onset of CV events among the tertiles. The prognostic ability of BNP was compared to an established risk score for embolic events (CHADS2 score). In addition, to determine the usefulness of BNP as a predictor in addition to CHADS2 score, we calculated Net Reclassification Improvement (NRI) and Integrated Discrimination Improvement (IDI) indices.

Results

During the follow-up period 58 subjects experienced CV events (52 per 1,000 person-years). The event-free ratio was significantly lower in the highest tertile (p < 0.02). After adjustment for established CV risk factors, the hazard ratio (HR) of the highest tertile was significantly higher than that of the lowest tertile (HR = 2.38; p < 0.02). The predictive abilities of plasma BNP in terms of sensitivity and specificity for general CV events were comparable to those of CHADS2 score. Adding BNP to the CHADS2 score only model improved the NRI (0.319; p < 0.05) and the IDI (0.046; p < 0.05).

Conclusion

Plasma BNP is a valuable biomarker both singly or in combination with an established scoring system for assessing general CV risk including stroke, heart failure and acute coronary syndrome in real-world AF subjects.     

A DNA marker closely linked to the <Emphasis Type="Italic">vrs1</Emphasis> locus (row-type gene) indicates multiple origins of six-rowed cultivated barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis> L.)

The origin of six-rowed cultivated barley was studied using a DNA marker cMWG699 closely linked to the vrs1 locus. Restriction patterns of the PCR-amplified product of the cMWG699 locus were examined in 280 cultivated (Hordeum vulgare ssp. vulgare) and 183 wild (H. vulgare ssp. spontaneum) barleys. Nucleotide sequences of the PCR products were also examined in selected accessions. Six-rowed cultivated barleys were divided into two distinct groups, types I and II. Type I six-rowed cultivated barley was distributed widely while type II six-rowed cultivated barley was found only in the Mediterranean region. The type I sequence was also found in a wild barley accession from Turkmenistan whereas the type II sequence was also found in a two-rowed cultivated barley from North Africa and a wild barley from Morocco. These results suggested that the six-rowed type I and II barleys were derived from two-rowed type I and II barleys, respectively, by independent mutations at the vrs1 locus. Received: 3 November 2000 / Accepted: 17 April 2001     

Expression of programmed death 1 ligands by murine T cells and APC

Programmed death 1 (PD-1) is a new member of the CD28/CTLA-4 family, which has been implicated in the maintenance of peripheral tolerance. Two ligands for PD-1, namely, B7-H1 (PD-L1) and B7-DC (PD-L2), have recently been identified as new members of the B7 family but their expression at the protein level remains largely unknown. To characterize the expression of B7-H1 and B7-DC, we newly generated an anti-mouse B7-H1 mAb (MIH6) and an anti-mouse B7-DC mAb (TY25). MIH6 and TY25 immunoprecipitated a single molecule of 43 and 42 kDa from the lysate of B7-H1 and B7-DC transfectants, respectively. Flow cytometric analysis revealed that B7-H1 was broadly expressed on the surface of mouse tumor cell lines while the expression of B7-DC was rather restricted. PD-1 was expressed on anti-CD3-stimulated T cells and anti-IgM plus anti-CD40-stimulated B cells at high levels but was undetectable on activated macrophages or DCs. B7-H1 was constitutively expressed on freshly isolated splenic T cells, B cells, macrophages, and dendritic cells (DCs), and up-regulated on T cells by anti-CD3 stimulation on macrophages by LPS, IFN-gamma, GM-CSF, or IL-4, and on DCs by IFN-gamma, GM-CSF, or IL-4. In contrast, B7-DC expression was only inducible on macrophages and DCs upon stimulation with IFN-gamma, GM-CSF, or IL-4. The inducible expression of PD-1 ligands on both T cells and APCs may suggest new paradigms of PD-1-mediated immune regulation.     

Gas chromatographic-mass spectrometric determination of erythrocyte 3-deoxyglucosone in diabetic patients

To determine if the erythrocyte levels of 3-deoxyglucosone (3-DG) are increased in diabetic patients, and if they correlate with glycemic status, they were measured in diabetic patients without renal disease as well as in healthy subjects. The erythrocyte levels of 3-DG were measured by a selected ion monitoring method of gas chromatography-chemical ionization mass spectrometry using [(13)C(6)]-3-DG as an internal standard. The erythrocyte levels of 3-DG were significantly higher in diabetic patients than in healthy subjects. The erythrocyte concentration of 3-DG was significantly and positively correlated with HbA1c (r=0.84, P<0.001). However, no significant correlation could be found between erythrocyte 3-DG and age, onset age of diabetes, or duration of diabetes in our group of diabetic patients. In diabetes, the production of 3-DG in the erythrocytes is increased via the polyol pathway and/or the Maillard reaction due to hyperglycemia.