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61.
Tetradecenyl succinic acid (TSA) is the major component of a detergent builder (C12-C14 alkenyl succinic acid), which is inherently biodegradable. 14C-TSA was dosed as a component of sewage sludge into a soil with a history of sludge amendment at final added concentrations of 1.5 and 30 mg (kg soil)-1. In addition, it was dosed to the soil in an aqueous solution to a final added concentration of 30 mg (kg soil)-1. Dose and form were found to have a pronouced effect on the mineralization kinetics. When dosed in a realistic form and concentration (i.e. 1.5 mg (kg soil)-1 as a component of sludge), TSA was mineralized at its highest rate and to its greatest extent, and the mineralization half-life was 2.4 days. When dosed at 30 mg (kg soil)-1 as a component of sludge, mineralization began immediately, and the half-life was 23 days. In contrast, when dosed at this concentration in aqueous solution, the onset of mineralization was preceded by a 13 day lag period and the mineralization half-life was 69 days. Primary biodegradation and mineralization rates of TSA were very similar. Approximately, half the radioactivity was evolved as 14CO2, while the remaining radioactivity became non-extractable, having presumably been incorporated into biomass or natural soil organic matter (humics). This study demonstrated that TSA is effectively removed from sludge-amended soils as a result of biodegradation. Furthermore, it showed the effect that dose form and concentration have on the biodegradation kinetics and the importance of dosing a chemical not only at a relevant concentration but also in the environmental form in which it enters the soil environment. 相似文献
62.
Carmen Sieiro Natalia M. Reboredo Tomás G. Villa 《Journal of industrial microbiology & biotechnology》1995,14(6):461-466
Summary A comparative study has been made of different laboratory and industrial wild-type strains ofSaccharomyces cerevisiae in relation to their flocculation behavior. All strains were inhibited by mannose and only one by maltose. In regard to the stability of these characters in the presence of proteases and high salt concentrations, a relevant degree of variation was found among the strains. This was to such an extent that it did not allow their inclusion in the Flol or NewFlo phenotypes. Genetic characterization of one wild-type strain revealed that the flocculation-governing gene was allelic toFLO1 found in genetic strains.This paper is dedicated to Professor Herman Jan Phaff in honor of his 50 years of active research which still continues. 相似文献
63.
64.
The existence of parentally imprinted gene expression in the somatic tissues of mammals and plants can be explained by a theory of intragenomic genetic conflict, which is a logical extension of classical parent-offspring conflict theory. This theory unites conceptually the phenomena of autosomal imprinting and X-chromosome inactivation. We argue that recent experimental studies of X-chromosome inactivation and andro-genetic development address previously published predictions of the conflict theory, and we discuss possible explanations for the occurrence of random X-inactivation in the somatic tissues of eutherians. © 1995 Wiley-Liss, Inc. 相似文献
65.
Mismatch Repair Genes on Chromosomes 2p and 3p Account for a Major Share of Hereditary Nonpolyposis Colorectal Cancer Families Evaluable by Linkage 总被引:17,自引:1,他引:16
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Minna Nystrm-Lahti Ramon Parsons Pertti Sistonen Lea Pylkknen Lauri A. Aaltonen Fredrick S. Leach Stanley R. Hamilton Patrice Watson Earlene Bronson Ramon Fusaro Jennifer Cavalieri Jane Lynch Stephen Lanspa Tom Smyrk Patrick Lynch Thomas Drouhard Kenneth W. Kinzler Bert Vogelstein Henry T. Lynch Albert de la Chapelle Pivi Peltomki 《American journal of human genetics》1994,55(4):659-665
Two susceptibility loci for hereditary nonpolyposis colo-rectal cancer (HNPCC) have been identified, and each contains a mismatch repair gene: MSH2 on chromosome 2p and MLH1 on chromosome 3p. We studied the involvement of these loci in 13 large HNPCC kindreds originating from three different continents. Six families showed close linkage to the 2p locus, and a heritable mutation of the MSH2 gene was subsequently found in four. The 2p-linked kindreds included a family characterized by the lack of extracolonic manifestations (Lynch I syndrome), as well as two families with cutaneous manifestations typical of the Muir-Torre syndrome. Four families showed evidence for linkage to the 3p locus, and a heritable mutation of the MLH1 gene was later detected in three. One 3p-linked kindred was of Amerindian origin. Of the remaining three families studied for linkage, one showed lod scores compatible with exclusion of both MSH2 and MLH1, while lod scores obtained in the other two families suggested exclusion of one HNPCC locus (MSH2 or MLH1) but were uninformative for markers flanking the other locus. Our results suggest that mismatch repair genes on 2p and 3p account for a major share of HNPCC in kindreds that can be evaluated by linkage analysis. 相似文献
66.
It has been proposed that peg formation in the vascular transition region (TR zone) between the hypocotyl and the root in
Cucurbitaceae seedlings is a gravimorphogenetic phenomenon. Initiation of the peg became visible 36 h after imbibition when
cucumber (Cucumis sativus L. cv. Burpee Hybrid II) seeds were germinated in a horizontal position at 24°C in the dark. Simultaneously, sedimented amyloplasts
(putative statoliths) were apparent in the sheath cells surrounding the vascular strands, and in the cortical cells immediately
adjacent to them, in the TR zone. In contrast, the other cortical cells, some of which were destined to develop into the peg,
contained amyloplasts which were not sedimented. These results suggest that the graviperception mechanism for peg formation
may be like that of statoliths in shoot gravitropism. By 48 h following imbibition, the cells of the TR zone still had sedimented
amyloplasts but had lost their sensitivity to gravity, possibly because of their maturation. 相似文献
67.
Partial sequencing and mapping of clones from two maize cDNA libraries 总被引:11,自引:0,他引:11
68.
Ann-ping Tsou Alan Kosaka Chinh Bach Patti Zuppan Calvin Yee Leonard Tom Robert Alvarez Scott Ramsey Douglas W. Bonhaus Eric Stefanich Lyn Jakeman Richard M. Eglen Hardy W. Chan 《Journal of neurochemistry》1994,63(2):456-464
Abstract: In a number of different cell types, phosphorylation of a 63-kDa protein has been shown to increase rapidly in response to stimuli that lead to an increase in intracellular calcium. Here, a stimulus-sensitive protein at this molecular weight is identified in PC12 cells and rat cortical synaptosomes as phosphoglucomutase. In addition, the added phosphate is shown to be in an oligosaccharide terminating in phosphodiester-linked glucose. In synaptosomes, incorporated radioactivity, following incubation with [14 C]glucose or the [β-35 S]phosphorothioate analogue of UDP-glucose, was found to increase within 5 s of stimulation and return to baseline within 25 s. Despite the many pathways utilizing glucose, this was the only detectable protein glycosylation observed in synaptosomes. These results indicate that cytoplasmic glycosylation is reversible and rapidly regulated, and suggest that phosphoglucomutase undergoes an alteration in function and/or topography in response to increases in intracellular calcium. 相似文献
69.
Michael M. Burrell Peter J. Mooney Margaret Blundy Dawn Carter Fiona Wilson John Green Keith S. Blundy Tom ap Rees 《Planta》1994,194(1):95-101
The aim of this work was to discover whether genetic manipulation of 6-phosphofructokinase [EC 2.7.1.11; PFK(ATP)] influenced the rate of respiration of tuber tissue of Solanum tuberosum L. Transgenic plants were produced that contained the coding sequence of the Escherichia coli pfkA gene linked to a patatin promoter. Expression of this chimaeric gene in tubers resulted in a 14to 21-fold increase in the maximum catalytic activity of PFK(ATP) without affecting the activities of the other glycolytic enzymes. Tubers, and aged disks of tuber tissue, from transformed plants showed no more than a 30% fall in the content of hexose 6-monophosphates; the other intermediates of glycolysis increased threeto eightfold. Fructose-2,6-bisphosphate was barely detectable in aged disks of transformed tubers. The relative rates of 14CO2 production from [1-14C]-and [6-14C]-glucose supplied to disks of transformed and control tubers were similar. Oxygen uptake and CO2 production by aged disks of transformed tubers did not differ significantly from those from control tubers. The same was true of CO2 production, in air, and in nitrogen, for tuber tissue. It is concluded that PFK(ATP) does not dominate the control of respiration in potato tubers.Abbreviations Fru2,6bisP
fructose-2,6-bisphosphate
- FW
freshweight
- GUS
-glucuronidase
- PFK(ATP)
6-phosphofructokinase
- PFK(PPi)
pyrophosphate: fructose-6-phosphate 1-phosphotransferase 相似文献
70.
The metabolism of wild-type Arabidopsis thaliana L. and its mutant TC265 were compared in order to reveal the role of the chloroplast glucose transporter. Plants were grown in a 12-h photoperiod. From 20 to 40 days after germination, starch per gram fresh weight of shoot in the mutant was four times that in the wild type. The extent of this difference did not alter during this period. Stereological analysis showed that the chloroplasts in the mutant were larger than those in the wild type; the thylakoids appeared to be distorted by the high starch content. [U-14C]Glucose and [U-14C]glycerol were supplied, separately, to excised leaves in the dark. [U-14C]Glucose was a good precursor of sucrose in the wild type and mutant; [U-14C]glycerol was a poor precursor of sucrose in both. The distribution of 14C in the wild type was used to calculate that the net flux was from hexose monophosphates to triose phosphates, not vice versa. During the first 4 h of the night the sugar content (75% sucrose, 20% glucose) of the leaves of the mutant dropped sharply, and at all times during the night it was less than that of the wild-type leaves. This drop in sugar coincided with a decrease in the rate of respiration. The growth rate of the mutant was less than that of the wild type. Addition of sucrose restored the rate of respiration at night and increased the rate of growth. It is argued that a major function of the glucose transporter in Arabidopsis chloroplasts is export of the products of starch breakdown that are destined for sucrose synthesis at night.We thank Professor C.R. Somerville for his generous gift of seed of the Arabidopsis mutant TC265. We are also grateful to Mr B. Chapman for assistance with the preparation of the sections for electron microscopy. R.N.T. thanks the Science and Engineering Research Council for a studentship. 相似文献