Characterization of two homologous yeast genes that encode mitochondrial iron transporters

Two different yeast genes were identified that when overexpressed suppressed the low iron growth defect of a mutation in the endoplasmic reticulum iron binding enzyme methyl sterol oxidase. These genes were determined to be novel and highly related. The deduced amino acid sequences indicated that both were membrane proteins having two identical histidine-rich motifs. The predicted proteins, while not ABC transporters, are homologous to a widely distributed family of transition metal transporters present in all kingdoms. Subcellular fractionation and fluorescence microscopy localized these gene products to mitochondria. Based on this result we term these genes Mitochondrial Fe Transporters (MFT). Cells with disruptions in both genes show a growth defect on low iron medium, suggesting that these genes have redundant function and can affect cytosolic iron levels. Measurement of mitochondrial iron in cells grown in iron-rich medium overexpressing MFT1 or MFT2 show a 2-5-fold increase in iron compared with mitochondria from control cells. These results suggest that the mitochondria may act as a reservoir for iron that can be mobilized and used for cytosolic purposes.     

Characterization of pyruvate decarboxylase genes from rice

The pdc1 gene encoding pyruvate decarboxylase has been isolated and sequenced from an IR54 rice genomic library. In contrast to a previously isolated intron-less rice genomic pdc, pRgpdc3, this gene contains five intervening introns in the coding region and corresponds to a cDNA clone, pRcpdc1, isolated from an IR54-cDNA library constructed from anaerobically-induced mRNAs. Comparison of the deduced amino acid sequence of this gene with that of the rice pdc2 and pdc3 showed 88% and 89% similarity, and 78% and 79% identity, respectively. Southern blots indicated that more than three genes constitute the pdc gene family in rice. pdc1 is highly inducible under anaerobic conditions. Rice pdc2 is also inducible by anoxia but to a much lesser extent than pdc1.     

Male and female flowers of the dioecious plant sorrel show different patterns of MADS box gene expression

Male and female flowers of the dioecious plant sorrel (Rumex acetosa) each produce three whorls of developed floral organs: two similar whorls of three perianth segments and either six stamens (in the male) or a gynoecium consisting of a fertile carpel and two sterile carpels (in the female). In the developing male flower, there is no significant proliferation of cells in the center of the flower, in the position normally occupied by the carpels of a hermaphrodite plant. In the female flower, small stamen primordia are formed. To determine whether the organ differences are associated with differences in the expression of organ identity genes, cDNA clones representing the putative homologs of B and C function MADS box genes were isolated and used in an in situ hybridization analysis. The expression of RAD1 and RAD2 (two different DEFICIENS homologs) in males and females was confined to the stamen whorl; the lack of expression in the second, inner perianth whorl correlated with the sepaloid nature of the inner whorl of perianth segments. Expression of RAP1 (a PLENA homolog) occurred in the carpel and stamen whorls in very young flower primordia from both males and females. However, as soon as the inappropriate set of organs ceased to develop, RAP1 expression became undetectable in those organs. The absence of expression of RAP1 may be the cause of the arrest in organ development or may be a consequence.     

Identification of two Y-box binding proteins that interact with the promoters of columbid annexin I genes

The aim of this study was to investigate the role of noradrenergic descending nervous pathways in external anal sphincter motility. For this purpose, the effects of intravenously injected adrenoceptor antagonist and agonist on the tonic electrical activity of this sphincter were studied in anesthetized cats. The effects of stimulating the region of the locus coeruleus and the effects of intravenous, intracerebroventricular and intrathecal injection of the above drugs on the electromyographic responses of this muscle to pudendal nerve stimulation were also investigated. The tonic sphincteric activity and the reflex response triggered by electrically stimulating pudendal afferent nerve fibers were inhibited by alpha1-adrenoceptor antagonist nicergoline and enhanced by alpha1-adrenoceptor agonist phenylephrine. Stimulation of the locus coeruleus area either inhibited or enhanced the reflex responses. Intracerebroventricular and intrathecal injection of the alpha2-adrenoceptor agonists, morphine and leu-enkephalin decreased the amplitude of these reflex responses. All the effects of opioids were blocked by naloxone and by spinalization performed at the cervical and lumbar levels. The direct response elicited by stimulating the sphincteric motor axons was not affected either by these drugs or by the brainstem stimulation. These results suggests the existence of a pontine neuronal network controlling the motility of the external anal sphincter via noradrenergic and opioid neurons.     

系列抗稻瘟病水稻亲本抗性基因的经典遗传学分析

以福伊A、谷丰A和全丰A等抗稻瘟病水稻不育系选育系谱中的谷农13、天谷B、福伊B、谷丰B、全丰B为母本,以CO39为轮回亲本的6个近等基因系和感病对照丽江新团黑谷(LTH)为父本,组配了包括亲本(P)、F1、F2 3个世代的遗传材料.以3个稻瘟病菌系进行苗期室内喷雾接菌鉴定,应用经典遗传学分析方法研究该系谱中的5个供试亲本抗瘟基因的遗传及其与CO39近等基因系中抗瘟基因的等位性关系.结果表明,谷农13、天谷B、福伊B、谷丰B和全丰B等5个亲本的抗瘟性由显性基因控制;谷农13、福伊B、谷丰B和全丰B中都含有2对与CO39近等基因系中Pi-1、Pi-2、Pi-3、Pi-4a、Pi-4b不 等位的显性抗稻瘟病基因;天谷B中含有3对显性抗稻瘟病基因,均与Pi-1、Pi-2、Pi-4a、Pi-4b不等位,但有1对与Pi-3等位.     

Characterization of two avian reoviruses that exhibit strain-specific quantitative differences in their syncytium-inducing and pathogenic capabilities

This report outlines the experimental, surgical, and prosthodontic protocols for a prospective clinical trial using the Endopore dental implant to replace single maxillary teeth. Twenty patients (10 male, 10 female) ranging in age from 30 to 60 years each received one implant (mean length 10.1 mm), which, after an initial healing period of 4 months, was restored with a single crown. Records collected included radiographs, Periotest mobility measurements, supragingival Plaque Index, and an assessment of peri-implant soft tissue health using pocket probing depths, sulcular bleeding following probing, and probing attachment levels. Radiographs were exposed at predetermined intervals following crown placement (1 and 6 months, and then yearly) in a standardized procedure using a specialized filmholder that attaches to each implant after removal of the crown. At the time of this preliminary report, all of the 20 implants placed had been uncovered and were in function; 16 of the implants had been in function for 6 months or more, 14 had passed 1 year of function, and 3 had passed the 2-year function point. There have been no failures to date.     

Characterization of rice endo-beta-glucanase genes (Gns2-Gns14) defines a new subgroup within the gene family

Because of its importance to cell function, the free-energy metabolism of the living cell is subtly and homeostatically controlled. Metabolic control analysis enables a quantitative determination of what controls the relevant fluxes. However, the original metabolic control analysis was developed for idealized metabolic systems, which were assumed to lack enzyme-enzyme association and direct metabolite transfer between enzymes (channelling). We here review the recently developed molecular control analysis, which makes it possible to study non-ideal (channelled, organized) systems quantitatively in terms of what controls the fluxes, concentrations, and transit times. We show that in real, non-ideal pathways, the central control laws, such as the summation theorem for flux control, are richer than in ideal systems: the sum of the control of the enzymes participating in a non-ideal pathway may well exceed one (the number expected in the ideal pathways), but may also drop to values below one. Precise expressions indicate how total control is determined by non-ideal phenomena such as ternary complex formation (two enzymes, one metabolite), and enzyme sequestration. The bacterial phosphotransferase system (PTS), which catalyses the uptake and concomitant phosphorylation of glucose (and also regulates catabolite repression) is analyzed as an experimental example of a non-ideal pathway. Here, the phosphoryl group is channelled between enzymes, which could increase the sum of the enzyme control coefficients to two, whereas the formation of ternary complexes could decrease the sum of the enzyme control coefficients to below one. Experimental studies have recently confirmed this identification, as well as theoretically predicted values for the total control. Macromolecular crowding was shown to be a major candidate for the factor that modulates the non-ideal behaviour of the PTS pathway and the sum of the enzyme control coefficients.     

Suppressors of an Arabidopsis thaliana phyB mutation identify genes that control light signaling and hypocotyl elongation

Ambient light controls the development and physiology of plants. The Arabidopsis thaliana photoreceptor phytochrome B (PHYB) regulates developmental light responses at both seedling and adult stages. To identify genes that mediate control of development by light, we screened for suppressors of the long hypocotyl phenotype caused by a phyB mutation. Genetic analyses show that the shy (short hypocotyl) mutations we have isolated fall in several loci. Phenotypes of the mutants suggest that some of the genes identified have functions in control of light responses. Other loci specifically affect cell elongation or expansion.     

Characterization of RNA-binding protein genes in cyanobacteria

A number of genes that encode RNA-binding proteins belonging to the RNP family have been identified in cyanobacteria. All of them are predicted to encode small proteins with a single RNA recognition motif, containing both the RNP1 and RNP2 conserved motifs, and a short auxiliary motif which in many cases contains an abundance of glycine residues. Mutagenesis experiments to characterize the function of some of these gene products are being carried out. In Synechococcus sp. PCC 7942, interruption of the rbpA gene results in slower growth with an altered pigment composition.     

A comparison of internal eliminated sequences in the genes that encode two K(+)-channel isoforms in Paramecium tetraurelia

The Foundation for Growth Science has been controlling the use of GH by its registration system, which includes a scoring system for the eligibility for GH treatment according to the diagnostic criteria for GH deficiency (GHD) established by the Study Group for Hypothalamo-pituitary Disorder of the Ministry of Health and Welfare. Until 1995, 28,876 patients with GHD (19,432 boys and 9,444 girls) had been registered as eligible for GH treatment. The number of patients registered in a year increased gradually till 1990 due to the unlimited hGH supply by recombinant techniques and the change in the criteria for GH treatment and the number registered became stable after 1990. The frequency of GH-treated patients is calculated to be 55.2/100,000 persons (72.2/100,000 in boys and 37.1/100,000 in girls) in patients born between 1960 and 1990. The highest frequency was 148.4/100,000 persons (191.7/ 100,000 boys and 103.7/100,000 girls) in 1981, when 2,278 patients (1,508 boys and 770 girls) were born. Eligibility for GH treatment is assessed according to the scoring system which is basically dependent on peak GH values in provocation tests so that standardization of GH values measured with the various commercial GH kits is required to avoid inequality of patients' access to the treatment. In samples obtained by GRF test in 10 normal volunteers, hGH was measured with seven human GH (hGH) kits at a laboratory center. Since the RIA value has been used historically for the diagnosis of GHD, the mean of two RIA measurements was selected as the basis for the standardization procedure and the linear regression formula was used for each hGH kit. After the freely available supply of hGH obtained by recombinant DNA techniques, the role of the Foundation for Growth Science has changed to avoid hGH abuse. Even with this regulation, the frequency of registered patients may indicate a tendency to GH overuse.