Flower bud opening and senescence in roses (Rosa hybrida L.)

The flower is the most significant and beautiful part of plants. Flowers are very useful organs in plant developmental phenomenon. During flower bud opening, various events takes place in a well defined sequence, representing all aspects of plant development, such as cell division, cellular differentiation, cell elongation or expansion and a wide spectrum of gene expression. The complexity of flower bud opening illustrates that various biological mechanisms are involved at different stages. Senescence represents the ultimate stage of floral development and results in wilting or abscission of whole flower or flower parts. Senescence is an active process and governed by a well defined cell death program. Once a flower bud opens, the programmed senescence of petal allows the removal of a metabolically active tissue. In leaves, this process can be reversed, but in floral tissue it cannot, indicating that a highly controlled genetic program for cell death is operating. The termination of a flower involves at least two, sometimes overlapping, mechanisms. In one, the perianth abscises before the majority of its cells initiate a cell death program. Abscission may occur before or during the mobilization of food reserves to other parts of the plant. Alternatively, the petals may be more persistent, so that cell deterioration and food remobilization occur while the petals are still part of the flower. The overall pattern of floral opening varies widely between plant genera, therefore, a number of senescence parameters have been used to group plants into somewhat arbitrary categories. Opening and senescence of rose flower is still an unsolved jigsaw in the world of floriculture industry and the mechanism behind the onset of the very early events in the sequence still remains to be elucidated. Hence, for advancing the knowledge on the pertinent aspect of bud opening and senescence the literature has been cited under this review.     

Individual and simultaneous treatment with antipsychotic aripiprazole and antidepressant trazodone inhibit sterol biosynthesis in the adult brain

Polypharmacy, or the simultaneous use of multiple drugs to treat a single patient, is a common practice in psychiatry. Unfortunately, data on the health effects of commonly used combinations of medications are very limited. In this study, we therefore investigated the effects and interactions between two commonly prescribed psychotropic medications with sterol inhibiting side effects, trazodone (TRZ), an antidepressant, and aripiprazole (ARI), an antipsychotic. In vitro cell culture experiments revealed that both medications alone disrupted neuronal and astroglial sterol biosynthesis in dose-dependent manners. Furthermore, when ARI and TRZ were combined, exposure resulted in an additive 7-dehydrocholesterol (7-DHC) increase, as well as desmosterol (DES) and cholesterol decreases in both cell types. In adult mice, at baseline, we found that the three investigated sterols showed significant differences in distribution across the eight assessed brain regions. Furthermore, experimental mice treated with ARI or TRZ, or a combination of both medications for 8 days, showed strong sterol disruption across all brain regions. We show ARI or TRZ alone elevated 7-DHC and decreased DES levels in all brain regions, but with regional differences. However, the combined utilization of these two medications for 8 days did not lead to additive changes in sterol disturbances. Based on the complex roles of 7-DHC derived oxysterols, we conclude that individual and potentially simultaneous use of medications with sterol biosynthesis-inhibiting properties might have undesired side effects on the adult brain, with as yet unknown long-term consequences on mental or physical health.     

Measurement of 7-dehydrocholesterol and cholesterol in hair can be used in the diagnosis of Smith-Lemli-Opitz syndrome

7-dehydrocholesterol (7-DHC) and cholesterol (CHOL) are biomarkers of Smith-Lemli-Opitz Syndrome (SLOS), a congenital autosomal recessive disorder characterized by elevated 7-DHC level in patients. Hair samples have been shown to have great diagnostic and research value, which has long been neglected in the SLOS field. In this study, we sought to investigate the feasibility of using hair for SLOS diagnosis. In the presence of antioxidants (2,6-ditert-butyl-4-methylphenol and triphenylphosphine), hair samples were completely pulverized and extracted by micro-pulverized extraction in alkaline solution or in n-hexane. After microwave-assisted derivatization with N,O-Bis(trimethylsilyl)trifluoroacetamide, the analytes were measured by GC-MS. We found that the limits of determination for 7-DHC and CHOL were 10 ng/mg and 8 ng/mg, respectively. In addition, good linearity was obtained in the range of 50–4000 ng/mg and 30–6000 ng/mg for 7-DHC and CHOL, respectively, which fully meets the requirement for SLOS diagnosis and related research. Finally, by applying the proposed method to real hair samples collected from 14 healthy infants and two suspected SLOS patients, we confirmed the feasibility of hair analysis as a diagnostic tool for SLOS. In conclusion, we present an optimized and validated analytical method for the simultaneous determination of two SLOS biomarkers using human hair.     

外来入侵植物的氮代谢及其土壤氮特征

研究了4种外来入侵植物(五爪金龙、南美蟛蜞菊、金腰箭和马缨丹)和1种本地植物鸡矢藤(对照)的氮代谢及其土壤氮特征.结果表明:外来人侵植物的组织硝酸还原酶活性、根际土壤NH4-N、NO3-N含量、蛋白酶活性和脲酶活性均较高,分别为鸡矢藤的1.65～4.34、1.56～2.15、1.72～3.11、1.43～3.23和1.41～3.33倍,而植物组织硝态氮含量则较低,仅为鸡矢藤的17.5%～50.6%.相关分析表明:植物组织硝酸还原酶活性与根际土壤总氮、NH4-N、NO3-N含量呈显著正相关(P<0.05),与蛋白酶活性和脲酶活性呈极显著正相关(P<0.01).这说明,外来植物入侵使土壤氮代谢加快,氮的生物有效性增强,氮同化能力提高,并且较好地将植物体氮素代谢与土壤氮素代谢协调起来.因此,较强的氮素同化能力与加速土壤氮素的转化可能是植物成功入侵的重要机制之一.     

Pyrroline-5-carboxylate reductase from Cucurbita cotyledons

Pyrroline-5-carboxylate reductase, which required reduced pyridine nucleotide and Δ′-pyrroline-5-carboxylate for proline synthesis, was isolated from pumpkin cotyledons. The enzyme was found in the soluble fraction and had a 4.5-fold greater activity with NADH than NADPH. The enzyme was inhibited by NH₂OH, NADP, ATP and slightly by proline. Glutathione or pyridoxal-5-phosphate had little effect on enzyme activity. The enzyme had a pH optimum between 7·0 and 7·6 and was not inhibited by high concentrations of NADH or Δ′-pyrroline-5-carboxylate.     

Identification of the coding region for the putidaredoxin reductase gene from the plasmid of Pseudomonas putida

The first 12 NH₂-terminal amino acids of the Pseudomonas putida putidaredoxin reductase were shown to be Met-Asn-Ala-Asn-Asp-Asn-Val-Val-Ile-Val-Gly-Thr. Comparison of these data with the DNA sequence of the BamHI-HindIII 197-base fragment derived from the PstI 2.2-kb fragment obtained from the P. putida plasmid showed that the putidaredoxin reductase gene was downstream from the cytochrome P-450 gene and the intergenic region had the 24-nucleotide sequence TAAACACATGGGAGTGCGTGCTAA. The Shine-Dalgarno sequence GGAG was detected in this region. The initiating triplet for the reductase gene was GTG, which normally codes for valine, but in the initiating codon position codes for methionine. From the amino acid sequence and X-ray data comparisons with other flavoproteins, what appears to be the AMP binding region of the FAD can be recognized in the NH₂-terminal portion of the reductase involving residues 5–35.This article was presented during the proceedings of the International Conference on Macromolecular Structure and Function, held at the National Defence Medical College, Tokorozawa, Japan, December 1985.     

Eigenschaften des Elektronentransportsystem von Mitochondrien des Protisten Acanthamoeba castellanii Neff. I. Zum Einfluß von Hemmstoffen auf verschiedene Akzeptorsysteme, getested mit einer modifizierten Thunbergtechnik

ZUSAMMENFASSUNG. Die Reduktionsgeschwindigkeit künstlicher Elektronenakzeptoren wurde mittels einer modifizierten Thunbergtechnik in Gegenwart isolierter Mitochondrien des Protisten Acanthamoeba castellanii Neff photometrisch gemessen. Die mit verschiedenen Elektronenakzeptoren und Atmungsketteninhibitoren gewonnenen Meßergebnisse erlauben uns folgendes Bild von der Konstitution der Atmungskette zu entwerfen: a) Der Elektronentransport läuft mindestens bis zum Cytochrom b /Coenzym Q-Komplex auf zwei verschiedenen Wegen ab. b) Eine Stimulierung sowohl des Succinat-Jodnitrotetrazolium-chlorid als auch des NADH-Ferricyanid Reduktasekomplexes unter dem Einfluß von Antimycin A läßt vermuten, daß in der Atmungskette dieses Protisten gewisse Nebengleise des Elektronentransports besonders gangbar sind.
SYNOPSIS. The reduction of artificial electron acceptors by isolated mitochondria of Acanthamoeba castellanii was measured by a modified Thunberg technic. The results with different electron acceptors and respiratory chain inhibitors suggest the following scheme for the constitution of the respiratory chain: a) the chain is divided into 2 different sequences, at least up to the cytochrome b /coenzyme Q complex. b) As seen from the stimulation of the succinate-iodonitrotetrazolium chloride and NADH-ferricyanide reductase complexes by antimycin A, certain alternate pathways of electron transport become more important than the normal one.     

Control of Aspergillus niger infection in varieties of Arachis hypogeae L. by supplementation of zinc ions during seed germination

Three varieties of Arachis hypogeae, GG 11, GG 20 and GG 24, were compared for resistance against A. niger. GG 20 showed the least disease severity. Infection with A. niger resulted in a rapid increase in NADPH oxidase, Glutathione reductase (GR) and salicylic acid in all the three varieties, indicating hyper increase of reactive oxygen species (ROS) and activation of phenyl propanoid pathway. Ferric reducing antioxidant power value was found to be decreasing due to infection in all the three varieties, confirming the role of ROS in pathogenesis. Since A. niger was found to cause pathogenesis by oxidative stress, the treatment of zinc was given as an antioxidant and its effect was studied. The application of zinc inhibited NADPH oxidase and GR activity in the control as well as in the infected GG 11 and GG 24 varieties but induced in the tolerant variety GG 20. Because zinc treatment could control the ROS in GG 11 and GG 24 varieties, disease severity was reduced but in GG 20 variety, zinc treatment aggravated ROS levels and also the disease severity. The protein profile of GG 20 in comparison to GG 11 and GG 24 varieties revealed one oligomeric protein of 110 kD as one of the responsible factors for its resistance. Total oil and its iodine value were found little higher in GG 20 variety than in other two varieties. It was found that the control of ROS could control the A. niger infection in Arachis hypogeae.     

Cd1-型亚硝酸盐还原酶脱氮工程菌的构建与表达

目的用基因工程技术将铜绿假单胞菌PAO1中nirS基因定向克隆至表达载体pQE-30上，使nirS基因得到高效表达。方法根据GenBank公布的nirS碱基序列和表达载体pQE-30的多克隆位点设计引物，以铜绿假单胞菌PAO1的基因组DNA为模板，应用PCR技术扩增目的片段nirS；之后经过BamH I和HindⅢ双酶切，定向克隆到pQE-30上，化学转化DH5α，构建含有重组质粒的转化子pQE30-nirS-DH5α；经酶切和测序鉴定，扩增产物的碱基序列与GenBank公布的序列完全吻合，再将重组质粒pQE30-nirS转化表达菌株SG13009构建脱氮基因工程菌pQE30-nirS-SG-13009（PNS）。最后用SDS-PAGE（IPTG浓度：0．05mmol／L；诱导温度：25℃；诱导时间：2～3h）和His-tag in-gel Stain鉴定cd1-型亚硝酸盐还原酶的分子量与特异性。结果构建了高效表达cd1-型亚硝酸盐还原酶的脱氮基因工程菌PNS。结论Cd1-型亚硝酸盐还原酶能够在脱氮基因工程菌PNS中得到正确和高效的表达。