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  • Saccharomyces cerevisiae  (58)
  • phosphorus  (43)
  • Analytical Chemistry and Spectroscopy
  • Chemical Engineering
  • Humans
  • Springer  (103)
  • 1990-1994  (103)
  • 1980-1984
  • 1925-1929
  • 1992  (103)
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Keywords
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  • 1990-1994  (103)
  • 1980-1984
  • 1925-1929
Year
  • 1
    Electronic Resource
    Electronic Resource
    Measurement of total dissolved phosphorus in small volumes of iron rich interstitial water (1992)
    Springer
    Aquatic sciences 54 (1992), S. 1-9 
    Details
    ISSN: 1420-9055
    Keywords: Sediment ; interstitial water ; phosphorus ; iron ; persulfate digestion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract It is shown that sorption of orthophosphate to iron compounds, formed during persulfate digestion, can cause a significant underestimation of total dissolved phosphorus in interstitial waters rich in iron and poor in phosphorus. Labelling the samples with carrier free32PO4 before digestion allows to correct for these losses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00877261
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  • 2
    Electronic Resource
    Electronic Resource
    Potentiation of antifungal activity of sesquiterpene dialdehydes againstCandida albicans and two other fungi (1992)
    Springer
    Cellular and molecular life sciences 48 (1992), S. 1162-1164 
    Details
    ISSN: 1420-9071
    Keywords: Polygodial ; warburganal ; antifungal activity ; Candida albicans ; Saccharomyces cerevisiae ; Pityrosporum ovale ; enhancing effect ; antioxidants ; vitamin C ; BHA ; anethole
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The antifungal activity of two drimane sesquiterpene dialdehydes, polygodial (1) and warburganal (2), alone and in combination with several other substances, was examined against three fungi,Candida albicans, Saccharomyces cerevisiae andPityrosporum ovale employing a broth dilution method. Anethole significantly synergized the activity of the two sesquiterpenoids againstC. albicans andS. cerevisiae however, it had only an, additive effect againstP. ovale. By contrast, two antioxidants, ascorbic acid (vitamin C) and BHA (butylated hydroxyanisole), noticeably enhanced the activity of the sesquiterpenoids againstP. ovale, but had no, effect againstC. albicans andS. cerevisiae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01948015
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  • 3
    Electronic Resource
    Electronic Resource
    Phylogenetic evidence for multiple Alu source genes (1992)
    Springer
    Journal of molecular evolution 35 (1992), S. 7-16 
    Details
    ISSN: 1432-1432
    Keywords: Alu source genes ; Humans ; Gorillas ; Retrotransposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A member of the young PV Alu sub-family is detected in chimpanzee DNA showing that the PV subfamily is not specific to human DNA. This particular Alu is absent from the orthologous loci in both human and gorilla DNAs, indicating that PV subfamily members transposed within the chimpanzee lineage following the divergence of chimpanzee from both gorilla and human. These findings and previous reports describing the transpositional activity of other Alu sequences within the human, gorilla, and chimpanzee lineages provide phylogenetic evidence for the existence of multiple Alu source genes. Sequences surrounding this particular Alu resemble known transcriptional control elements associated with RNA polymerase III, suggesting a mechanism by which cis-acting elements might be acquired upon retrotransposition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00160256
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  • 4
    Electronic Resource
    Electronic Resource
    Phylogenetic analysis of the thiolase family. Implications for the evolutionary origin of peroxisomes (1992)
    Springer
    Journal of molecular evolution 35 (1992), S. 147-155 
    Details
    ISSN: 1432-1432
    Keywords: Thiolase ; Peroxisome evolution ; Bootstrap analysis ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The thiolase family is a widespread group of proteins present in prokaryotes and three cellular compartments of eukaryotes. This fact makes this family interesting in order to study the evolutionary process of eukaryotes. Using the sequence of peroxisomal thiolase from Saccharomyces cerevisiae recently obtained by us and the other known thiolase sequences, a phylogenetic analysis has been carried out. It shows that all these proteins derived from a primitive enzyme, present in the common ancestor of eubacteria and eukaryotes, which evolved into different specialized thiolases confined to various cell compartments. The evolutionary tree obtained is compatible with the endosymbiotic theory for the origin of peroxisomes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00183226
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  • 5
    Electronic Resource
    Electronic Resource
    The evolution of two west African populations (1992)
    Springer
    Journal of molecular evolution 34 (1992), S. 336-344 
    Details
    ISSN: 1432-1432
    Keywords: Humans ; Mitochondrial DNA ; Nuclear polymorphisms ; Heteroplasmy ; Genetic differentiation ; Sickle cell ; Rain forest refuges
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The identification of genetically coherent populations is essential for understanding human evolution. Among the culturally uniform ethnic groups of west Africa, there are two geographically distinct populations with high frequencies of sickle-cell hemoglobin (HbS). Although the HbS mutation in each group is found on distinguishable chromosomes 11, these populations have been assumed to be parts of a single population. Analysis of mitochondrial DNA (mtDNA) in these populations demonstrated that the two populations identified by alternative chromosomes 11 bearing HbS have distinct distributions of mitochondrial genotypes, i.e., they are maternally separate. These studies also showed that, contrary to expectation, the mtDNA of some individuals is heteroplasmic. For nuclear loci, a comparison of the frequency of alternative alleles established that these populations are genetically distinct. Both the mitochondrial and nuclear data indicate that these populations have been separate for approximately 50,000 years. Although HbS in the two populations is usually attributed to recent, independent mutations, the duration of the separation and the observed geographic distribution of the population allow for the possibility of an ancient origin of HbS. Assuming an ancient mutation and considering the known biogeography, we suggest that HbS protected selected populations from malaria in rain forest refuges during the most recent ice age.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00160241
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  • 6
    Electronic Resource
    Electronic Resource
    The determination of phosphonate base scale inhibitors in brines by plasma spectrometry (1992)
    Springer
    Microchimica acta 109 (1992), S. 201-209 
    Details
    ISSN: 1436-5073
    Keywords: phosphonate base scale inhibitor ; brine ; direct current plasma ; inductively coupled plasma atomic emission spectrometry ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The determination of phosphonate base scale inhibitors in brines by direct current plasma (DCP) and inductively coupled plasma atomic emission spectrometry (ICP-AES) is described. The first method is based on a direct nebulization of the brine samples and plasma using the phosphorus line at 213.618 nm. The second method involves extraction of phosphorus as phospho-antimonyl molybdate complex into methylisobutyl ketone (MIBK) phase and analysis of the extract for molybdenum using the Mo 313.260 nm line. Comparison between the proposed methods and an established recommended method [1] shows excellent agreement between the results in addition to the sensitivity and ease of automation provided by AES.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01242475
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  • 7
    Electronic Resource
    Electronic Resource
    The interpretation of Olsen extractable P values in relation to recommendations for the fertilizer requirements of crops (1992)
    Springer
    Nutrient cycling in agroecosystems 32 (1992), S. 223-227 
    Details
    ISSN: 1573-0867
    Keywords: Soil testing ; phosphorus ; relative yield
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A greenhouse experiment, with Okra (Abelmoschus esculentus L.) as the test crop, was conducted on twenty-one soils ranging in Olsen's extractable phosphorus from 1.8 to 15.5µg Pg−1 soil. The experiment was conducted at Punjab Agricultural University, Ludhiana, India. The soils were nonsaline with pH ranging from 7.7 to 8.6. A critical level of 2.55µg Pg−1 soil was predicted by Cate and Nelson's (1971) statistical procedure. Because of a wide range in relative yields, this value did not accurately predict response to applied P. An approach to compute minimum response to applied fertilizer, which is likely to be obtained at a particular Olsen P level, has been presented. It involves calculation of lower 60 percent confidence limits for relative yield and fitting loge-linear regression to the transformed data. The regression was tested on a published data set and was found to hold well.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01048784
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  • 8
    Electronic Resource
    Electronic Resource
    Two post thinning fertilizer trials inPinus radiata in New South Wales, Australia (1992)
    Springer
    Nutrient cycling in agroecosystems 32 (1992), S. 259-267 
    Details
    ISSN: 1573-0867
    Keywords: Nitrogen ; phosphorus ; timber increment ; fertilization ; Pinus radiata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Two trials inPinus radiata growing on different sites in N.S.W. allowed consideration of fertilizer applications after 2nd or 3rd thinning. The trials included factorial applications of N and P at a single thinning intensity plus a further treatment which allowed assessment of different thinning intensities. The most significant growth responses were obtained by application of N and P in combination. The largest response (additional productivity compared with the unfertilized control) occurred 4 years after application and after 7 years there was no additional absolute response for either of the two sites. The largest fertilizer response was 70 m3 ha−1 over 7 years on one site and 36 m3 ha−1 on the other, indicating differences in absolute responses between sites. It was concluded that in planning treatments the most responsive sites near the end of the rotation should be selected to maximise economic returns. Foliage analyses indicated differences between sites at the commencement of the study. It was concluded that either a single year of foliage analyses at study commencement is of value, or sampling every year of the study should be used to analyse responses, but a single year of analysis during or at the end of the study would not be of value.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01050363
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  • 9
    Electronic Resource
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    The genetics of nuclear pre-mRNA splicing: a complex story (1992)
    Springer
    Antonie van Leeuwenhoek 62 (1992), S. 35-46 
    Details
    ISSN: 1572-9699
    Keywords: introns ; pre-mRNA splicing ; RNA processing ; Saccharomyces cerevisiae ; yeast genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The occurrence of introns in nuclear precursor RNAs (pre-mRNAs) is widespread in eukaryotes, and the splicing process that removes them is basically the same in yeasts as it is in higher eukaryotes. Splicing takes place in a very large, multi-component complex, the spliceosome, and biochemical studies have been complicated by the large number of splicing factors involved. This review describes how genetic approaches used to study RNA splicing inSaccharomyces cerevisiae have complemented the biochemical studies and led to rapid advances in the field.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00584461
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  • 10
    Electronic Resource
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    Nutrient-chlorophyll trajectories across trophic gradients (1992)
    Springer
    Aquatic sciences 54 (1992), S. 58-76 
    Details
    ISSN: 1420-9055
    Keywords: Eutrophication ; lake management ; phosphorus ; nitrogen ; chlorophyll-a ; slope estimator
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We estimate the response of chl-a (mg · m−3) to changes in concentrations of total phosphorus (TP) by calculating the slopeS = Δchl-a/ΔTP in chl-a =f(TP) graphs. Results show that in years where algae are P-limited oligotrophic lakes respond less (median slope 0.21) to changes in nutrient concentrations than eutrophic lakes, (median slope 0.31) and these again less than hypereutrophic lakes, (median slope 1.02). We find no saturation value for the slope within the TP range considered (6–480 mg · m−3). Chl-a in eutrophic lakes responds more frequently to non-nutrient factors than oligotrophic and hypereutrophic lakes. Results obtained by replacing TP with a new nutrient parameter, TP′ = 0.056 · TP · IN0.226, in which inorganic nitrogen, IN, is factored in, suggest that nitrogen has an influence on chl-a in oligotrophic lakes. Blue-green algae respond less to changes in TP than other algal species, e.g., diatoms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00877264
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  • 11
    Electronic Resource
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    Possibilities and limitations of lake restoration: Conclusions for Lake Lugano (1992)
    Springer
    Aquatic sciences 54 (1992), S. 381-390 
    Details
    ISSN: 1420-9055
    Keywords: Eutrophication ; phosphorus ; lake restoration ; internal restoration measures for lakes ; Swiss lakes ; Lake Lugano (Lago di Lugano)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In most lakes eutrophication is linked to an excessive input of phosphorus. Lake restoration by reduction of P-input (external measure) has led to a considerable drop of the P-concentration in all major Swiss lakes as well as in many other lakes. Internal restoration measures such as artificial mixing, drainage of hypolimnetic water, flushing, aeration, biomanipulation and others serve to improve and accelerate the response of a lake to external measures. For the case of Lago di Lugano, a simple two-box model is employed to demonstrate that a reduction of the P-input to about 25% of the present values is necessary to reach the “P-criterion” (P-concentration below 30 µg/l). Internal measures could possibly accelerate the extremely slow response of the northern basin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00878149
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  • 12
    Electronic Resource
    Electronic Resource
    DNA integration into recipient yeast chromosomes by trans-kingdom conjugation between Escherichia coli and Saccharomyces cerevisiae (1992)
    Springer
    Current genetics 21 (1992), S. 101-108 
    Details
    ISSN: 1432-0983
    Keywords: Trans-kingdom conjugation ; DNA integration ; Saccharomyces cerevisiae ; Escherichia coli
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary IncQ-derived conjugative shuttle vectors, which carried the yeast gene URA3 and/or the yeast autonomously replicating sequence (ARS1), were constructed. Both the ars-plus plasmid pAY205 and the ars-less plasmid pAY201 were successfully transmitted from E. coli to S. cerevisiae by the action of mob and tra. In this trans-kingdom conjugation, plasmid pAY205 could replicate and be retained in transconjugants. Plasmid pAY201 caused the formation of “micro-colonies” of abortive transconjugants due to its transient expression and rapid disappearance. Nevertheless, one per about 103 colonies caused by transmitted pAY201 plasmids were uncurable by integration into the homologous region of a yeast chromosome. Analyses by restriction enzyme mapping and Southern hybridization indicate that this integration is primarily caused by a double crossover during conjugation and not by a single reciprocal recombination.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318467
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  • 13
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    The PAR1 (YAP1/SNQ3) gene of Saccharomyces cerevisiae, ac-jun homologue, is involved in oxygen metabolism (1992)
    Springer
    Current genetics 21 (1992), S. 269-273 
    Details
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Transcriptional activator ; Oxidative stress ; Glutathione
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The PAR1/SNQ3 gene of S. cerevisiae, which increases resistance to iron chelators in multi-copy transformants, is identical to the YAP1 gene, a yeast activator protein isolated as a functional homologue of the human c-jun oncogene by binding specifically to the AP-1 consensus box. The observed H2O2-sensitivity of par1 mutants has been attributed to an increased sensitivity to reduced oxygen intermediates. Accordingly, par1 mutants did not survive an elevated oxygen pressure and were very sensitive to menadione and methylviologene, two chemicals enhancing the deleterious effects of oxygen. The specific activities of enzymes involved in oxygen detoxification, such as superoxide dismutase, glucose 6-phosphate dehydrogenase and glutathione reductase, were decreased in par1 mutants and increased after PAR1 over-expression. As in the case of oxygen detoxification enzymes, the cellular levels of glutathione were similarly affected. These observations indicate that PAR1/YAP1/SNQ3 is involved in the gene regulation of certain oxygen detoxification enzymes. The finding that H2O2 promotes DNA-binding of human c-jun is consistent with a similar function for PAR1/YAP1/SNQ3 and c-jun in cellular metabolism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00351681
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  • 14
    Electronic Resource
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    An yeast nuclear mutation conferring temperature-sensitivity to the mitochondrial tryptophanyl-tRNA synthetase (1992)
    Springer
    Current genetics 21 (1992), S. 281-283 
    Details
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Mitochondrial trp-tRNA synthetase ; Nuclear mutation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The conditional respiratory-deficient Saccharomyces cerevisiae mutant pet-ts2281 was complemented by an yeast genomic DNA library. The gene thus isolated was sequenced and proved to be identical to the known MSW1 sequence encoding mitochondrial tryptophanyl-tRNA synthetase (Myers and Tzagoloff 1985). Compared to the wild-type, the ts2281 mutant allele of MSW1 contained a single T→C transition leading to a Leu→Ser replacement at position 294 of the protein sequence. In addition to this mutational alteration, our sequence data for the wild-type gene differ from the originally published MSW1 sequence at five other DNA positions which affect two locally restricted regions of the polypeptide chain. As expected, at the non-permissive temperature ts2281 cells are specifically defective in mitochondrial trp-tRNA formation and, thus, in overall mitochondrial protein synthesis. In addition, the patterns of cytochrome b mRNA maturation intermediates were distinctly different in ts2281 and wild-type yeast cells. The mutational effect of the observed amino-acid substitution in ts2281 is discussed in terms of weakened hydrogen bonding in the C-terminal half of the MSW1-encoded protein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00351683
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  • 15
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    Starvation for His-tRNAHis in yeast causes translational arrest without a high level of misincorporation of glutamine at histidine codons (1992)
    Springer
    Current genetics 21 (1992), S. 177-182 
    Details
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Aminoacyl-tRNA synthetase mutant ; PGK overexpression ; In vivo misreading
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The hts1.1 temperature-sensitive histidinyl-tRNA synthetase mutation enables Saccharomyces cerevisiae to be starved for His-tRNAHis by upshift to the non-permissive temperature of 38°C. If yeast behaves similarly to bacterial and mammalian cells, this lack of His-tRNAHis should greatly enhance misreading at histidine codons (CAU/CAC) by Gln-tRNAGln, resulting in substitution of the neutral amino acid glutamine in place of histidine, a basic amino acid. Such misreading causes the isoelectric point (pI) of proteins to shift to lower values, and is readily detectable as “stuttering” on two-dimensional (2D) protein gels. By gel analysis of pulse-labelled proteins of hts1.1 yeast cells that were overexpressing phosphoglycerate kinase (PGK), our study sought to detect this specific translational error in PGK protein. It was not detected by this relatively sensitive technique, indicating that missense errors due to glutamine insertion at histidine codons do not occur in yeast at the readily-detectable level found in bacterial and mammalian cells.
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    URL: http://dx.doi.org/10.1007/BF00336838
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  • 16
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    Genetic mapping of 1,3-β-glucanase-encoding genes in Saccharomyces cerevisiae (1992)
    Springer
    Current genetics 22 (1992), S. 283-288 
    Details
    ISSN: 1432-0983
    Keywords: 1,3-β-glucanase genes ; Saccharomyces cerevisiae ; Chromosomal mapping ; Genetic mapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The map position of three 1,3-β-glucanase-encoding genes in S. cerevisiae has been determined following conventional meiotic and mitotic mapping combined with recombinant DNA techniques. EXG1, EXG2 and SSG1 were localized to chromosomes XII, IV and XV, respectively, by hybridizing the cloned genes to Southern blots of chromosomes sepaated by pulsed-field gel electrophoresis, in conjunction with the rad52-1-dependent chromosome-loss mapping technique. Meiotic tetrad analyses further localized the EXG1 gene 6.1 centimorgans centromere-proximal to CDC25 on the right arm of chromosome XII. EXG2 was positioned between LYS4 and GCN2 on the right arm of chromosome IV, at distances of 6.2 centimorgans from LYS4 and 4.9 centimorgans from GCN2. Finally, the SSG1 locus mapped on the right arm of chromosome XV, about 8.2 centimorgans to the centromere-proximal side of HIS3.
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    URL: http://dx.doi.org/10.1007/BF00317922
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  • 17
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    Direct induction of tetraploids or homozygous diploids in the industrial yeast Saccharomyces cerevisiae by hydrostatic pressure (1992)
    Springer
    Current genetics 22 (1992), S. 371-376 
    Details
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Hydrostatic pressure ; Tetraploidy ; Homozygous diploid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Hydrostatic pressure and a dye plate method were used to investigate the direct induction of tetraploids or homozygous diploids from the industrial diploid or haploid yeast Saccharomyces cerevisiae. Above 200 MPa, hydrostatic pressure greatly inactivated the strains HF399s1 (α haploid), P-540 (a/α diploid), and P-544 (a/α diploid). At the same time, when pressure-treated cells of these strains were spread on a dye plate, some of the visible colonies were stained red/blue or dark blue (variant colonies); the rest stained violet, similar to colonies originating from diploid cells or haploid cells that were not pressure-treated. In addition, above 100 MPa, the formation of variant colonies increased with increasing pressure, and maximized (1x10-1) at 200 and 250 MPa, respectively. The size of almost all variant cells from P-544, P-540, and HF399s1 was visibly increased compared with that of untreated cells and the measured cellular DNA content of P-540 and HF399s1 was double that of untreated cells. Furthermore, based on random spore analysis and mass-matings, induced variants in the diploid strains were found to be tetraploid with an a/a/α/α genotype at the mating-type locus or, in the haploid strains, homozygous diploid with an α/α genotype. From these results we conclude that pressure treatment in combination with a dye plate is a useful method for strain improvement by direct induction of tetraploids or homozygous diploids from industrial strains whether diploid or haploids.
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    URL: http://dx.doi.org/10.1007/BF00352438
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  • 18
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    Mechanism of resistance to sulphite in Saccharomyces cerevisiae (1992)
    Springer
    Current genetics 22 (1992), S. 435-440 
    Details
    ISSN: 1432-0983
    Keywords: Sulphite-resistant mutants ; Sulphite uptake ; Acetaldehyde accumulation ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Growth inhibition and cell killing caused by sulphite were reduced in seven Saccharomyces cerevisiae sulphite-resistant independent mutants, compared to their parental strains. Genetic analysis showed that in the seven mutants resistance was inherited as a single-gene dominant mutation and that all the analyzed mutations were allelic, thus identifying a major gene responsible for sulphite resistance in S. cerevisiae. Two of the mutants, MBS20-9 and MBS30, were further characterized. 35S-sulphite uptake experiments showed that the ability to accumulate sulphite was markedly reduced in the two resistant strains. No difference between resistant and sensitive strains with respect to glyceraldehyde-3-phosphate dehydrogenase sensitivity to sulphite, or to intracellular glutathione content, were revealed. In contrast, the extracellular acetaldehyde concentration was higher in the resistant mutants, both in the presence and in the absence of sulphite.
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    URL: http://dx.doi.org/10.1007/BF00326407
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  • 19
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    Mitochondrial DNA loss by yeast reentry-mutant cells conditionally unable to proliferate from stationary phase (1992)
    Springer
    Current genetics 22 (1992), S. 471-477 
    Details
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Stationary phase ; mtDNA ; Storage carbohydrate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Double-mutant cells of the budding yeast Saccharomyces cerevisiae harboring the gcs1-1 and sed1-1 mutations are conditionally defective (cold-sensitive) only for reentry into the mitotic cycle from stationary phase. If already proliferating at the permissive temperature (29°C), these reentry-mutant cells continue to proliferate when transferred to the restrictive temperature of 14°C, but under these conditions reentry-mutant cells lose mitochondrial DNA (mtDNA). In addition, upon exhaustion of the nutrient supply at 14°C, these reentry-mutant cells entered stationary phase at a decreased cell concentration and did not accumulate the reserve carbohydrates trehalose and glycogen. Both of these deficiencies were due to the loss of mtDNA, as shown by the responses of wild-type cells also lacking mtDNA. Mitochondrial status did not affect other aspects of the reentry-mutant phenotype. Although mitochondrial activity and the accumulation of carbohydrate reserves are typical features of cells in stationary phase, the reentry-mutant phenotype reveals that neither entry into nor exit from stationary phase need involve mitochondrial function.
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    URL: http://dx.doi.org/10.1007/BF00326412
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  • 20
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    Inactivation of the RAD1 excision-repair gene does not affect correction of mismatches on heteroduplex plasmid DNA in yeast (1992)
    Springer
    Current genetics 21 (1992), S. 261-263 
    Details
    ISSN: 1432-0983
    Keywords: Mismatch correction ; Saccharomyces cerevisiae ; Excision repair ; DNA methylation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The efficiency and direction of mismatch correction in the Saccharomyces cerevisiae SUP4-o gene were not altered by an excision-repair defect (rad1). Although excision-repair functions remove methylated adenine from yeast, adenine methylation at a GATC sequence in SUP4-o did not direct the correction of mismatches via excision repair.
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    URL: http://dx.doi.org/10.1007/BF00336851
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  • 21
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    Repair of ultraviolet light damage in Saccharomyces cerevisiae as studied with double- and single-stranded incoming DNAs (1992)
    Springer
    Current genetics 21 (1992), S. 93-94 
    Details
    ISSN: 1432-0983
    Keywords: DNA repair ; Incoming DNA ; Saccharomyces cerevisiae ; Ultraviolet light
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Purified double- and single-stranded DNAs of the autonomously replicating vector M13RK9-T were irradiated with ultraviolet light (UV) in vitro and introduced into competent whole cells of Saccharomyces cerevisiae. Incoming double-stranded DNA was more sensitive to UV in excision repair-deficient rad2-1 cells than in proficient repair RAD + cells, while single-stranded DNA exhibited high sensitivity in both host cells. The results indicate that in yeast there is no effective rescue of UV-incoming single-stranded DNA by excision repair or other constitutive dark repair processes.
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    URL: http://dx.doi.org/10.1007/BF00318465
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    The identification of 18 nuclear genes required for the expression of the yeast mitochondrial gene encoding cytochrome c oxidase subunit 1 (1992)
    Springer
    Current genetics 21 (1992), S. 139-146 
    Details
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Mitochondria ; Cytochrome c oxidase subunit 1 ; RNA processing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Eighteen nuclear mutants of the yeast Saccharomyces cerevisiae, each disturbed in the biosynthesis of the mitochondrially encoded cytochrome c oxidase subunit 1 (cox 1) and each representing a distinct complementation group, have been examined to identify the level at which COX1 expression is affected. RNA blotting revealed that most have a defect in the processing of COX1 precursor-mRNA; only a few are defective in COX1 transcription and/or pre-mRNA stability. In most RNA-processing mutants, the absence of the COX1 messenger results from a defect in the splicing of one or more COX1 introns. In turn, this defect can be ascribed to a mutation in a nuclear gene which is either directly involved in splicing or else acts indirectly by impairing COX1 translation.
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    URL: http://dx.doi.org/10.1007/BF00318473
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    Cloning and mapping of the CYS4 gene of Saccharomyces cerevisiae (1992)
    Springer
    Current genetics 21 (1992), S. 285-289 
    Details
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Cysteine biosynthetic ; CYS4 ; Mapping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A DNA fragment containing the CYS4 gene of Saccharomyces cerevisiae was isolated from a genomic library. The cloned fragment hybridized to the transverse-alternating-field-electrophoresis band corresponding to chromosomes VII and XV. According to the 2 μm DNA chromosome-loss procedure, the cys2 and cys4 mutations, which are linked together and co-operatively confer cysteine dependence, were assigned to chromosome VII. By further mapping involving tetrad analysis, the cys2-cys4 pair was localized between SUP77 (SUP166) and ade3 on the right arm of chromosome VII.
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    Genetic analysis of serine biosynthesis and glucose repression in yeast (1992)
    Springer
    Current genetics 21 (1992), S. 295-300 
    Details
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Serine biosynthesis ; Mutant isolation ; Glucose repression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Serine and glycine biosynthesis in yeast proceed by two pathways; a “glycolytic” pathway, using 3-phosphoglycerate, and a “gluconeogenic” pathway, using glyoxylate. We used a mutation in the cat1 gene to abolish the glucose-repressible “gluconeogenic” pathway and re-isolated two mutants, ser1 and ser2, in the “glycolytic” pathway. The ser1 mutation corresponded to phosphoserine transaminase and ser2 to that of phosphoserine phosphatase. Mutagenesis of a ser1 ser2 cat1 triple mutant facilitated the isolation of a mutation in a new gene, SER10. SER10 appears to be part of a pathway which, under normal growth conditions, is less important in serine biosynthesis. The ser1 ser2 ser10 triple mutants were totally serine auxotrophic on glucose media but serine prototrophic during growth on non-fermentable carbon sources. This phenotype was used to select for possible regulatory mutants that synthesize serine by the gluconeogenic pathway even in the presence of glucose, e.g., with a non-glucose repressible glyoxylate cycle. In an alternative approach to isolate such mutants URA3 and TRP1 expression were placed under the control of the glucose-repressible FBP1 (fructose-1,6-bisphosphatase) promoter. Although both systems resulted in strong selection pressure we could not isolate constitutively derepressed mutants. These results indicate that transcription of glucose-repressible gluconeogenic enzymes is mainly dependent on positive regulatory elements.
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    Complementation of the Saccharomyces cerevisiae srb1-1 mutation: an autoselection system for stable plasmid maintenance (1992)
    Springer
    Current genetics 21 (1992), S. 339-344 
    Details
    ISSN: 1432-0983
    Keywords: Yeast ; Saccharomyces cerevisiae ; Lysis mutants ; Plasmid stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The autonomously replicating plasmid YEpSS1, containing the S. cerevisiae SOD1 and SRB1 genes, was highly unstable in a wild-type strain. When transformed into a fragile srb1-1 mutant host, the same plasmid displayed different characteristics depending on the growth medium used. Both batch and continuous culture experiments demonstrated that the plasmid was very unstable when the transformed strain SLU15 was grown in the presence of an osmotic stabiliser (10% w/v sorbitol). However, in the absence of the osmoticum, nearly 100% of the cells retained the plasmid and produced the Sod1 protein after 80 generations of growth.
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    URL: http://dx.doi.org/10.1007/BF00351692
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    Analysis of the chromosomal DNA polymorphism of wine strains of Saccharomyces cerevisiae (1992)
    Springer
    Current genetics 22 (1992), S. 1-7 
    Details
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Wine yeasts ; Chromosome length polymorphism ; TAFE ; Probe hybridization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Wine yeast strains are characterized by a high chromosomal DNA polymorphism. This can be explained partly by a size difference of different variants of specific chromosomes. This difference can reach up to 45% of the size of the chromosome in question. Two strains, SB1 and Eg8, have a very complex chromosomal pattern and show one band hybridizing with probes from two different chromosomes derived from a reference strain. This is an indication of the presence of “hybrid” chromosomes in these wine strains. The most astonishing result concerns chromosome VIII, frequently present in wine strains in two variant forms. The first normal form has a size of about 580 kb while the second is around 1000 kb. These two forms segregate at meiosis and recombine with a normal chromosome VIII from a laboratory strain. Wine yeasts are thus very different from haploid laboratory strains.
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    6-Azauracil inhibition of GTP biosynthesis in Saccharomyces cerevisiae (1992)
    Springer
    Current genetics 22 (1992), S. 9-11 
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    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; IMP dehydrogenase ; 6-azauracil ; GTP level
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The addition of 6-azauracil to the growth medium causes a strong reduction of the GTP level in the nucleotide pool of Saccharomyces cerevisiae. In-vitro experiments show a strong inhibition of IMP dehydrogenase activity by 6-azaUMP explaining the preceeding effect. PPR2 mutants, previously characterized by an increased sensitivity to 6-azauracil compared to the wildtype, are specifically susceptible to the lowering of the GTP pool, and are able to grow in presence of 6-azauracil when guanine is added to the medium.
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    Construction and growth properties of a yeast strain defective in sterol 14-reductase (1992)
    Springer
    Current genetics 22 (1992), S. 267-272 
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    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Sterol 14-reductase ; Ergosterol ; Fenpropidin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have transformed Saccharomyces cerevisiae with a genomic library contained in the replicative vector pFL44. The resulting transformants were screened for resistance to fenpropidin, a specific inhibitor of sterol 14-reductase. A plasmid was isolated that transformed yeast both to resistance to fenpropidin and to an increased specific activity of sterol 14-reductase. Sterol analysis of transformed cells grown in the presence of increasing concentrations of the inhibitor confirmed that resistance was a consequence of over-production of sterol 14-reductase. By chromosomal gene disruption, we have, for the first time, constructed yeast strains defective in sterol 14-reductase. As expected, since yeast in unable to take up sterols in aerobiosis, the disrupted strains do not grow in the presence of oxygen, even if exogenous sterols are supplied. However, disrupted cells grow in anaerobiosis with exogenous oleic acid and ergosterol supplemens. They also grow in aerobiosis if they bear an additional mutation allowing sterol uptake. In this last growth condition the cells require a “sparking” ergosterol supplementation (25nM) and accumulate ignosterol (ergosta-8, 14-dienol) as the end-product of the sterol pathway. These results reveal that ignosterol is not obviously toxic to yeast membranes and strongly suggest that the molecular basis of the antifungal-activity morpholine and piperidine is directly related to the specific inhibition of ergosterol formation.
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    Identification of UAS elements and binding proteins necessary for derepression of Saccharomyces cerevisiae fructose-1,6-bisphosphatase (1992)
    Springer
    Current genetics 22 (1992), S. 363-370 
    Details
    ISSN: 1432-0983
    Keywords: Saccharomyces cerevisiae ; Fructose-1,6-bisphosphatase ; Glucose repression ; Gene activation ; Gluconeogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Fructose-1,6-bisphosphatase is a key enzyme in gluconeogenesis and the FBP1 gene is not transcribed during growth with glucose. Genetic analysis indicated a positive regulation of FBP1 expression after exhaustion of glucose. By linker-deletion analysis, two upstream activation sites (UAS1 and UAS2) were localized and the respective UAS-binding factors (DAP I and DAP II for derepression activating protein) were identified by gel retardation. UAS1 and UAS2 span about 30 bp each, and are separated by approximately 30 bp. Both UAS sites act synergistically. Although UAS1 showed some similarities to the DNA-binding consensus for the general yeast activator Rap1, competition experiments and DEAE-chromatography proved that DAP I and Rap1 correspond to different proteins. Gel retardation by DAP I depended on carbon sources and did not occur in cells growing logarithmically with glucose, whereas a strong retardation signal was obtained with ethanol-grown cells. The present results suggest that DAP I and DAP II are the final regulatory elements for glucose derepression.
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    The influence of Congo red on the cell wall and (1 → 3)-β-d-glucan microfibril biogenesis in Saccharomyces cerevisiae (1992)
    Springer
    Archives of microbiology 158 (1992), S. 115-126 
    Details
    ISSN: 1432-072X
    Keywords: Saccharomyces cerevisiae ; Yeast cells ; Yeast protoplasts ; Cell wall ; Congo red ; (1 » 3)-β-d-glucan microfibrils ; Cytokinesis ; Reversion of walled protoplasts to cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Congo red was applied to growing yeast cells and regenerating protoplasts in order to study its effects on wall biogenesis and cell morphogenesis. In the presence of the dye, the whole yeast cells grew and divided to form chains of connected cells showing aberrant wall structures on both sides of the septum. The wall-less protoplasts in solid medium with the dye exhibited an abnormal increase in volume, regeneration of aberrant cell walls and inability to carry out cytokinesis or protoplast reversion to cells. In liquid medium, the protoplasts synthesized glucan nets composed mainly of thin fibrils orientated at random, whereas normally, in the absence of dye, the nets consist of rather thick fibrils, 10 to 20 nm in width, assembled into broad ribbons. These fibrils are known to consist of triple 6/1 helical strands of (1 » 3)-β-d-glucan aggregated laterally in crystalline packing. The thin fibrils (c. 4 to 8 nm wide) can contain only a few triple helical strands (c. 1.6 nm wide) and are supposed to be prevented from further aggregation and crystallization by complexing with Congo red on their surfaces. Some loose triple 6/1 helical strands (native elementary fibrils) are also discernible. They represent the first native (1 » 3)-β-d-glucan elementary fibrils depicted by electron microscopy. The effects of Congo red on growth and the wall structure in normal cells and regenerating protoplasts in solid medium can be explained by the presence of a complex which the dye forms with (helical) chain parts of the glucan network and which results in a loss of rigidity by a blocked lateral interaction between the helices.
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    Saccharomyces cerevisiae and Neurospora crassa contain heavy metal sequestering phytochelatin (1992)
    Springer
    Archives of microbiology 157 (1992), S. 305-310 
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    ISSN: 1432-072X
    Keywords: Phytochelatin ; Metallothionein ; Heavy metal detoxification ; Saccharomyces cerevisiae ; Neurospora crassa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In fungi, cellular resistance to heavy metal cytotoxicity is mediated either by binding of metal ions to proteins of the metallothionein type or by chelation to phytochelatin-peptides of the general formula (γ-Glu-Cys)n-Gly. Hitherto, only one fungus, Candida glabrata has been shown to contain both metal inactivating systems. Here we show by unambiguous FAB-MS analysis that both a metallothionein-free mutant of Saccharomyces cerevisiae as well as a wildtype strain synthesize phytochelatin (PC2) upon exposure to 250 μM Cd2+ ions. The presence of Zn and/or Cu ions in the nutrient broth also induces PC2 synthesis in this organism. By 109Cd exchange and subsequent monobromobimane fluorescence HPLC, it could be shown that the presence of Cd2+ in the growth medium also induces phytochelatin synthesis in Neurospora crassa, which contains metallothioneins.
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    Cloning of a cDNA for rape chloroplast 3-isopropylmalate dehydrogenase by genetic complementation in yeast (1992)
    Springer
    Plant molecular biology 18 (1992), S. 557-566 
    Details
    ISSN: 1573-5028
    Keywords: Brassica napus ; chloroplast ; 3-isopropylmalate dehydrogenase ; molecular evolution ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Both insect and mammalian genes have previously been cloned by genetic complementation in yeast. In the present report, we show that the method can be applied also to plants. Thus, we have cloned a rape cDNA for 3-isopropylmalate dehydrogenase (IMDH) by complementation of a yeast leu2 mutation. The cDNA encodes a 52 kDA protein which has a putative chloroplast transit peptide. The in vitro made protein is imported into chloroplasts, concomitantly with a proteolytic cleavage. We conclude that the rape cDNA encodes a chloroplast IMDH. However, Southern analysis revealed that the corresponding gene is nuclear. In a comparison of IMDH sequences from various species, we found that the rape IMDH is more similar to bacterial than to eukaryotic proteins. This suggests that the rape gene could be of chloroplast origin, but has moved to the nucleus during evolution.
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    An EPR and molecular mechanics study of radical adducts of phosphonyl radicals with 2-hydroperfluoro-4-methyl-and 4,4-dimethyl-2-pentene (1992)
    Springer
    Russian chemical bulletin 41 (1992), S. 2008-2011 
    Details
    ISSN: 1573-9171
    Keywords: EPR ; radical ; fluorine ; conformation ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract EPR spectra of radical adducts of phosphonyl radicals with 2-hydroperfluoro-4-methyl- and 4,4-dimethyl-2-pentene have been studied. The molecular mechanics method has been used to determine the preferred conformation of the (CF3)2CF-CF-HCF3P(O)(OMe)2 radical. The eclipsed conformation of the C–P bond and 2p z -orbital of an unpaired electron is stabilized due to steric factor and hyperconjugation.
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    Yeast calmodulin localizes to sites of cell growth (1992)
    Springer
    Protoplasma 166 (1992), S. 110-113 
    Details
    ISSN: 1615-6102
    Keywords: Calmodulin ; Ca2+ ; Cell polarity ; Budding yeast ; Saccharomyces cerevisiae ; Microfilament
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Intracellular localization of calmodulin was examined in the budding yeast,Saccharomyces cerevisiae. Distribution of calmodulin changes in a characteristic way during the cell cycle. Calmodulin localizes to a patch at the presumptive bud site of unbudded cells. It concentrates at the bud tip in small-budded cells, and later it diffuses throughout the entire bud. At cytokinesis, calmodulin is largely at the neck between the mother and daughter cells. Double staining experiments have shown that the location of some polarized actin dots is coincident with that of calmodulin dots. Polarized localization of actin dots is observed in cells depleted of calmodulin, suggesting that calmodulin is not required for localization of the actin dots. Thecdc24 mutant that has a defect in bud assembly at the restrictive temperature fails to exhibit polarized localization of calmodulin, indicating that theCDC24 gene product is responsible for controlling the polarity of calmodulin.
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    Identification of a site required for DNA replication fork blocking activity in the rRNA gene cluster in Saccharomyces cerevisiae (1992)
    Springer
    Molecular genetics and genomics 233 (1992), S. 355-362 
    Details
    ISSN: 1617-4623
    Keywords: Saccharomyces cerevisiae ; Replication fork block ; rRNA gene ; 2 gm Plasmid ; 2D agarose gel electrophoresis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The yeast genome has DNA replication fork blocking sites, that we have named sog sites, in the ribosomal RNA gene (rDNA) cluster. These are located at the 3′ end of the 35S rRNA transcription unit and they block replication fork movement in a direction opposite to that of RNA polymerase I. We cloned this replication blocking site into a YEp-type plasmid and analyzed DNA replication intermediates, using two-dimensional (2D) agarose gel electrophoresis. The blocking activity remained even on a plasmid not involved in 35S rRNA transcription and inhibited fork movement in the same polar fashion as on the yeast chromosome. To define the site further, smaller fragments were subcloned into the YEp-type plasmid. A small 109 by region exhibited sog activity and was located near the enhancer region for 35S rRNA transcription. It overlaps an essential element of the recombinational hot spot HOT1.
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    Molecular structure of the DNA cross-link repair gene SNM1(PSO2) of the yeast Saccharomyces cerevisiae (1992)
    Springer
    Molecular genetics and genomics 231 (1992), S. 194-200 
    Details
    ISSN: 1617-4623
    Keywords: Saccharomyces cerevisiae ; DNA repair ; Nitrogen mustard ; Interstrand cross-links ; Nucleotide sequence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A 3.2 kb yeast DNA fragment containing the DNA interstrand cross-link-specific repair gene SNM1 has been sequenced. Two genes were identified. SNM1 has an open reading frame of 1983 by and codes for a 661 amino acid protein. Hydrophobic analysis shows that the protein is most probably not directly membrane bound. The second gene, UGX1, has an open reading frame of 573 by coding for a polypeptide of 191 amino acid residues. The two genes are arranged head to head and share a 192 by divergent promoter region that contains three TATAAA motives, two for the SNM1 and one for the UGX1 locus. Gene UGX1 has no apparent influence on the sensitivity of the cell to cross-linking nitrogen mustard, as its disruption in wild type does not increase sensitivity to nitrogen mustard and the presence of multiple copies of the gene fails to complement the nitrogen mustard sensitivity phenotype of snm1 disruption mutants. Northern analysis revealed that the expression of SNM1 yields an average of 0.3 copies/cell of a 2.4 kb transcript, while expression of UGX1 yields higher levels of a 0.8 kb poly(A)+ RNA.
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    Chromatin structure of the yeast SUC2 promoter in regulatory mutants (1992)
    Springer
    Molecular genetics and genomics 231 (1992), S. 395-400 
    Details
    ISSN: 1617-4623
    Keywords: SUC2 ; Saccharomyces cerevisiae ; Chromatin ; Micrococcal nuclease ; Promoter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have previously suggested that two positioned nucleosomes are removed from the promoter of the Saccharomyces cerevisiae SUC2 gene upon derepression by glucose starvation. To gain further insight into the changes accompanying derepression at the chromatin level we have studied the chromatin structure of the SUC2 promoter in several mutants affecting SUC2 expression. The non-derepressible mutants snf1, snf2 and snf5 present a chromatin structure characteristic of the repressed state, irrespective of the presence or absence of glucose. The non-repressible mutants, mig1 and ssn6, as well as the double mutant snfs sn6 exhibit an opened chromatin structure even in the presence of glucose. These results suggest that the DNA-binding protein encoded by MIG1 is necessary to produce the characteristic pattern of repressed chromatin and that the SNF1 protein kinase is sufficient to produce the derepressed chromatin pattern. A model is presented for the transitions that result in opening up of the chromatin structure.
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    Functional conservation between Schizosaccharomyces pombe ste8 and Saccharomyces cerevisiae STE11 protein kinases in yeast signal transduction (1992)
    Springer
    Molecular genetics and genomics 235 (1992), S. 122-130 
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    ISSN: 1617-4623
    Keywords: Schizosaccharomyces pombe ; Saccharomyces cerevisiae ; Signal transduction ; Sexual differentiation ; Protein kinase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In fission yeast (Schizosaccharomyces pombe), the mat1-Pm gene, which is required for entry into meiosis, is expressed in response to a pheromone signal. Cells carrying a mutation in the ste8 gene are unable to induce transcription of mat1-Pm in response to pheromone, suggesting that the ste8 gene product functions in the signal transduction pathway. The ste8 + gene encodes a 659 amino acid putative protein kinase, which is identical to the previously identified byr2 suppressor of the ras1 defect. Furthermore, ste8 + is highly homologous to the Saccharomyces cerevisiae STE11 gene, which functions in signal transduction in budding yeast. Expression of the S. cerevisiae STE11 gene in S. pombe ste8 mutants restores the ability to transcribe mat1-Pm in response to pheromone. Also, such cells become capable of conjugation and sporulation. When mat1-Pm is artifically expressed from a heterologous promoter, ste8 mutant cells will enter meiosis. This demonstrates that the meiotic defect of ste8 mutants is due to the absence of the mat1-Pm gene product.
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    The pso4-1 mutation reduces spontaneous mitotic gene conversion and reciprocal recombination in Saccharomyces cerevisiae (1992)
    Springer
    Molecular genetics and genomics 235 (1992), S. 311-316 
    Details
    ISSN: 1617-4623
    Keywords: pso4-1 mutation ; Saccharomyces cerevisiae ; Mitotic recombination ; 8-Methoxypsoralen photoreaction ; his4 gene duplication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Spontaneous mitotic recombination was examined in the haploid pso4-1 mutant of Saccharomyces cerevisiae and in the corresponding wild-type strain. Using a genetic system involving a duplication of the his4 gene it was shown that the pso4-1 mutation decreases at least fourfold the spontaneous rate of mitotic recombination. The frequency of spontaneous recombination was reduced tenfold in pso4-1 strains, as previously observed in the rad52-1 mutant. However, whereas the rad52-1 mutation specifically reduces gene conversion, the pso4-1 mutation reduces both gene conversion and reciprocal recombination. Induced mitotic recombination was also studied in pso4-1 mutant and wild-type strains after treatment with 8-methoxypsoralen plus UVA and 254 nm UV irradiation. Consistent with previous results, the pso4-1 mutation was found strongly to affect recombination induction.
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    The yeast RNA1 protein, necessary for RNA processing, is homologous to the human ribonuclease/angiogenin inhibitor (RAI) (1992)
    Springer
    Molecular genetics and genomics 233 (1992), S. 315-318 
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    ISSN: 1617-4623
    Keywords: RNA1 ; Ribonuclease/angiogenin inhibitor ; Homology ; RNA metabolism ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mutations in theRNA1 gene ofSaccharomyces cerevisiae, which encodes an essential cytosolic protein, affect the production and processing of all major classes of RNA. The mechanisms underlying these effects are not at all understood. Detailed comparative sequence analyses revealed that the RNA1 protein belongs to a superfamily, the members of which contain repetitive “leucine-rich motifs” (LRM). Within this superfamily RNA1 is most closely related to the ribonuclease/angiogenin inhibitor (RAI), which is a tightly binding inhibitor of ribonucleolytic activities in mammals. These results not only provide important clues to the structure, function and evolution of the RNAI protein, but also have intriguing implications for possible novel functions of RAI.
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    The two genes encoding protein synthesis initiation factor eIF-5A in Saccharomyces cerevisiae are members of a duplicated gene cluster (1992)
    Springer
    Molecular genetics and genomics 233 (1992), S. 487-490 
    Details
    ISSN: 1617-4623
    Keywords: Saccharomyces cerevisiae ; Translation ; Initiation factor ; Chromosomal mapping ; Pulsed-field electrophoresis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Translation initiation factor eIF-5A is an abundant protein in which a lysine residue is modified by spermidine to form the amino acid derivative, hypusine. The factor is encoded by two genes in Saccharomyces cerevisiae, called TIF51A and TIF51B, which are regulated reciprocally by oxygen and by heme. TIF51B, also called ANBI, is located on chromosome X in a region called COR. We physically mapped TIF51A and its associated serine tRNA2 gene by the method of chromosome fragmentation and pulsed-field gel electrophoresis. TIF5IA maps 90 kb from the left end of chromosome V in a region called ARC. The COR and ARC regions contain CYCI and CYC7, respectively, and appear to be duplications carrying numerous related genes. The arrangements of related genes in the two regions are incompatible with a duplication mechanism involving a circular intermediate.
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    Dual function of a new nuclear gene for oxidative phosphorylation and vegetative growth in yeast (1992)
    Springer
    Molecular genetics and genomics 232 (1992), S. 58-64 
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    ISSN: 1617-4623
    Keywords: Essential gene ; Respiration ; Mutants ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A new gene essential for cell viability and indispensable for the biogenesis of a functional respiratory chain in Saccharomyces cerevisiae was isolated by complementing a temperature-sensitive mutant. This conditional nuclear mutation selectively affects oxidative phosphorylation at restrictive temperatures. At the molecular level a severe and complex defect inside mitochondria is observed, with drastically reduced levels of mitochondrial transcripts. Surprisingly a null mutation in this nuclear gene in a haploid yeast strain leads to cell death. Spores containing a disrupted copy of the gene exhibit a severe growth defect and cell division stops irreversibly after 3 to 4 days. It is shown that the null and conditional mutants are indeed allelic. This finding demonstrates a dual function of the gene product in oxidative phosphorylation and vegetative growth. The putative protein product, as deduced from the sequence of the relevant reading frame is characterized by a low molecular weight of approximately 14 kDa, a high content of charged amino acids and a very low codon bias index. A transcript of low abundance and with a length of about 600 nucleotides can be assigned to this gene.
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    URL: http://dx.doi.org/10.1007/BF00299137
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    Regulation of the yeast RAD2 gene DNA damage-dependent induction correlates with protein binding to regulatory sequences and their deletion influences survival (1992)
    Springer
    Molecular genetics and genomics 232 (1992), S. 247-256 
    Details
    ISSN: 1617-4623
    Keywords: DNA damage ; Excision repair ; Saccharomyces cerevisiae ; Gene regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the yeast Saccharomyces cerevisiae the RAD2 gene is absolutely required for damage-specific incision of DNA during nucleotide excision repair and is inducible by DNA-damaging agents. In the present study we correlated sensitivity to killing by DNA-damaging agents with the deletion of previously defined specific promoter elements. Deletion of the element DRE2 increased the UV sensitivity of cells in both the G1/early S and S/G2 phases of the cell cycle as well as in stationary phase. On the other hand, increased UV sensitivity associated with deletion of the sequence-related element DRE1 was restricted to cells irradiated in G1/S. Specific binding of protein(s) to the promoter elements DRE1 and DRE2 was observed under non-inducing conditions using gel retardation assays. Exposure of cells to DNA-damaging agents resulted in increased protein binding that was dependent on de novo protein synthesis.
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    URL: http://dx.doi.org/10.1007/BF00280003
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    Expression of yeast cytochrome C1 is controlled at the transcriptional level by glucose, oxygen and haem (1992)
    Springer
    Molecular genetics and genomics 232 (1992), S. 447-459 
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    ISSN: 1617-4623
    Keywords: Saccharomyces cerevisiae ; Cytochrome c 1 ; Promoter dissection ; HAP1, HAP2 transcription factors ; Centromere and promoter-binding factor (CPF1)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The nuclear gene for cytochrome c 1 in Saccharomyces cerevisiae (CYT1) was localized on chromosome XV. Its upstream region was identified by functional complementation. Fusion to the lacZ reporter gene on a CEN plasmid allowed study of the effect of carbon sources and of specific deletion mutations on expression of the gene in yeast transformants. Detailed promoter analysis combined with expression studies in recipient strains defective in regulatory genes identified cis-acting sites and transcription factors involved in the regulated expression of the cytochrome c 1 gene. These analyses showed that, in the presence of glucose, transcription of CYT1 is positively controlled by oxygen, presumably through the haem signal, and mediated by the HAP1-encoded transactivator. It is additionally regulated by the HAP2/3/4 complex which mediates gene activation mainly under glucose-free conditions. Basal transcription is, in part, effected by CPF1, a centromere and promoter-binding factor.
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    URL: http://dx.doi.org/10.1007/BF00266250
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    TheNAM8 gene inSaccharomyces cerevisiae encodes a protein with putative RNA binding motifs and acts as a suppressor of mitochondrial splicing deficiencies when overexpressed (1992)
    Springer
    Molecular genetics and genomics 233 (1992), S. 136-144 
    Details
    ISSN: 1617-4623
    Keywords: Saccharomyces cerevisiae ; Nuclear gene ; Mitochondrial splicing ; Suppression ; RNA binding proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have characterized the nuclear geneNAM8 inSaccharomyces cerevisiae. It acts as a suppressor of mitochondrial splicing deficiencies when present on a multicopy plasmid. The suppressed mutations affect RNA folding and are located in both group I and group II introns. The gene is weakly transcribed in wildtype strains, its overexpression is a prerequisite for the suppressor action. Inactivation of theNAM8 gene does not affect cell viability, mitochondrial function or mitochondrial genome stability. TheNAM8 gene encodes a protein of 523 amino acids which includes two conserved (RNP) motifs common to RNA-binding proteins from widely different organisms. This homology with RNA-binding proteins, together with the intronic location of the suppressed mitochondrial mutations, suggests that the NAM8 protein could be a non-essential component of the mitochondrial splicing machinery and, when present in increased amounts, it could convert a deficient intron RNA folding pattern into a productive one.
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    URL: http://dx.doi.org/10.1007/BF00587571
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    The role of promoter elements of a ribosomal protein gene in Saccharomyces cerevisiae under various physiological conditions (1992)
    Springer
    Molecular genetics and genomics 234 (1992), S. 22-32 
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    ISSN: 1617-4623
    Keywords: cis-acting elements ; Saccharomyces cerevisiae ; Transcriptional regulation ; Ribosomal protein genes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Previous work in our laboratory has shown that the 5′ nontranscribed promoter region of the gene for ribosomal protein (rp) S16A-1 of Saccharomyces cerevisiae, when fused to a lacZ gene, is necessary and sufficient to cause an increase in expression of the heterologous lacZ gene fusion product after cells have been shifted from a glycerol to glucose carbon source. This increase in expression is characteristic of that observed with the native rp gene. We have sought to define more precisely those areas of the promoter that may be involved in the differential expression/regulation of RPS16A-1 when host cells are subjected to a variety of nutritional environments. It has already been demonstrated by others that the promoter regions of most rp genes contain at least one consensus element, designated UASrpg, which is necessary for the transcriptional activation and maintenance of expression of the gene during steady-state growth in rich media. Our main experimental approach has been to create a series of 5′ end deletions in the promoter region of RPS16A-1. The individual truncated promoter fragments were then ligated to a lacZ fusion reporter construct. By assaying the cells for production of β-galactosidase and determining the abundance of lacZ mRNA, we have been able to determined the extent of fusion product expression. We assayed cells under three physiological conditions: steady-state growth in glucose, steady-state growth in glycerol and during sporulation. We report four main findings of our work.
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    URL: http://dx.doi.org/10.1007/BF00272341
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    NPK1, a nonessential protein kinase gene in Saccharomyces cerevisiae with similarity to Aspergillus nidulans nimA (1992)
    Springer
    Molecular genetics and genomics 234 (1992), S. 164-167 
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    ISSN: 1617-4623
    Keywords: Saccharomyces cerevisiae ; Protein kinase ; Nonessential gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A new protein kinase gene [called NPKI (for nonessential protein kinase)] has been found on chromosome I of Saccharomyces cerevisiae between CDC15 and ADE1. The 435 amino acid/48 kDa gene product is very similar to known protein kinases. It is most closely related to the nimA protein of Aspergillus nidulans, displaying 45.9% identity and 63.5% similarity in the protein kinase domain. A 1.4 kb transcript of the NPKI gene was detected. Disruption of the NPKI gene impedes neither growth on glucose or a variety of other carbon sources, nor mating or sporulation.
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    URL: http://dx.doi.org/10.1007/BF00272358
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    ore2, a mutation affecting proline biosynthesis in the yeast Saccharomyces cerevisiae, leads to a cdc phenotype (1992)
    Springer
    Molecular genetics and genomics 234 (1992), S. 193-200 
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    ISSN: 1617-4623
    Keywords: Saccharomyces cerevisiae ; Cell cycle ; Proline ; DNA sequencing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We report here the isolation of temperature-sensitive mutants of the yeast Saccharomyces cerevisiae which exhibit cdc phenotypes. The recessive mutations defined four complementation groups, named ore1, ore2, ore3 and ore4. At the non-permissive temperature, strains bearing these mutations arrested in the G1 phase of the cell cycle. The wild-type allele of the gene altered in ore2 mutants was cloned. The nucleotide sequence of a fragment which can complement the mutation showed the presence of an open reading frame capable of encoding a protein with 286 amino acid residues. The deduced amino acid sequence showed 25% identity with that of the Escherichia coli Δ1-pyrroline-5-carboxylate reductase, an enzyme of the pathway for the biosynthesis of proline. The ore2 mutants, correspondingly, were found to be capable of growing at the non-permissive temperature on a synthetic medium supplemented with proline. In addition, the chromosomal location of the gene and its restriction map were compatible with those previously reported for the PRO3 gene which encodes the S. cerevisiae Δ1-pyrroline-5-carboxylate reductase.
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    URL: http://dx.doi.org/10.1007/BF00283839
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    Positive regulation of the LPD1 gene of Saccharomyces cerevisine by the HAP2/HAP3/HAP4 activation system (1992)
    Springer
    Molecular genetics and genomics 231 (1992), S. 296-303 
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    ISSN: 1617-4623
    Keywords: Saccharomyces cerevisiae ; Lipoamide dehydrogenase ; HAP activation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The LPD1 gene of Saccharomyces cerevisiae, encoding lipoamide dehydrogenase (LPDH), is subject to catabolite repression. The promoter of this gene contains a number of motifs for DNA-binding transcriptional activators, including three which show strong sequence homology to the core HAP2/HAP3/HAP4 binding motif. Here we report that transcription of LPD1 requires HAP2, HAP3 and HAP4 for release from glucose repression. In the wild-type strain, specific activity of LPDH was increased 12-fold by growth on lactate, 10-fold on glycerol and four- to five-fold on galactose or raffinose, compared to growth on glucose. In hap2, hap3 and hap4 null mutants, the specific activities of LPDH in cultures grown on galactose and raffinose showed only slight induction above the basal level on glucose medium. Similar results were obtained upon assaying for β-galactosidase production in wild-type, or hap2, hap3 or hap4 mutant strains carrying a single copy of the LPD1 promoter fused in frame to the lacZ gene of Escherichia coli and integrated at the URA3 locus. Transcript analysis in wild-type and hap2 mutants confirmed that the HAP2 protein regulates LPD1 expression at the level of transcription in the same way as it does for the CYC1 gene. Site-directed mutagenesis of the putative HAP2/HAP3/HAP4 binding site at −204 relative to the ATG start codon showed that this element was required for full derepression of the LPD1 gene on non-fermetable substrates.
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    URL: http://dx.doi.org/10.1007/BF00279803
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    The CDC26 gene of Saccharomyces cerevisiae is required for cell growth only at high temperature (1992)
    Springer
    Molecular genetics and genomics 231 (1992), S. 329-331 
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    ISSN: 1617-4623
    Keywords: Saccharomyces cerevisiae ; Cell division cycle ; CDC26 ; Nuclear division
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have cloned and sequenced the wild-type CDC26 gene and a mutant allele, cdc26-1, of Saccharomyces cerevisiae. Nucleotide sequence analysis revealed that the gene we cloned was the same as SCD26, a dosage-dependent suppressor of cdc26. However, the cloned gene is in fact the CDC26 gene, because a nucleotide substitution in cdc26-1 was found to be a nonsense mutation in this sequence. Disruption of this gene conferred thermosensitive cell growth and the disrupted cdc26 gene could not complement the cdc26-1 mutant allele. Thus, the CDC26 gene is required for cell growth only at high temperature.
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    URL: http://dx.doi.org/10.1007/BF00279807
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    Characterization of a staurosporine- and temperature-sensitive mutant, stt1, of Saccharomyces cerevisiae: STT1 is allelic to PKC1 (1992)
    Springer
    Molecular genetics and genomics 231 (1992), S. 337-344 
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    ISSN: 1617-4623
    Keywords: Saccharomyces cerevisiae ; Staurosporine ; Protein kinase C ; Cell cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Staurosporine is an antibiotic that specifically inhibits protein kinase C. Fourteen staurosporine- and temperature-sensitive (stt) mutants of Saccharomyces cerevisiae were isolated and characterized. These mutants were divided into ten complementation groups, and characterized for their cross-sensitivity to K-252a, neomycin, or CaCl2, The STT1 gene was cloned and sequenced. The nucleotide sequence of the STT1 gene revealed that STT1 is the same gene as PKC1. The STT1 gene conferred resistance to staurosporine on wild-type cells, when present on a high copy number plasmid. STT1/stt1::HIS3 diploid cells were more sensitive to staurosporine than STT1/STT1 diploid cells. Analysis of temperature-sensitive stt1 mutants showed that the STT1 gene product functioned in S or G2/M phase. These results suggest that a protein kinase (the STT1 gene product) is one of the essential targets of staurosporine in yeast cells.
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    URL: http://dx.doi.org/10.1007/BF00292700
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    SCM4, a gene that suppresses mutant cdc4 function in budding yeast (1992)
    Springer
    Molecular genetics and genomics 235 (1992), S. 285-291 
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    ISSN: 1617-4623
    Keywords: Saccharomyces cerevisiae ; Cell cycle ; CDC4 ; Suppression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The gene SCM4 encodes a protein which suppresses a temperature-sensitive allele of the cell division cycle gene CDC4 in Saccharomyces cerevisiae. SCM4 was cloned on a 1.8 kb BamHI fragment of yeast genomic DNA in the high copy-number vector pJDB207, which results in a 50- to 100-fold increase in the level of the 700 nucleotide SCM4 transcript in vivo. The SCM4 gene encodes a 20.2 kDa protein of 187 aminoacids with a clear tripartite domain structure in which a region rich in charged residues separates two domains of largely uncharged amino acids. Although the apparent allele specificity of cdc4 suppression suggests that the CDC4 and SCM4 proteins interact, disruption of SCM4 demonstrates that the gene product is not essential for mitosis or meiosis; however, it may be a member of a family of related, functionally redundant proteins.
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    URL: http://dx.doi.org/10.1007/BF00279372
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    Influence of DNA repair defects (radl, rad52) on nitrogen mustard mutagenesis in yeast (1992)
    Springer
    Molecular genetics and genomics 235 (1992), S. 304-310 
    Details
    ISSN: 1617-4623
    Keywords: Excision repair (RAD1) ; Mutational specificity ; Nitrogen mustard ; Saccharomyces cerevisiae ; Double-strand break repair (RAD52)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Nitrogen mustard (HN2) mutagenesis of a plasmid-borne copy of the Saccharomyces cerevisiae SUP4-o gene was examined in a repair-proficient yeast strain and isogenic derivatives defective for excision (radl) or DNA double-strand break (rad52) repair. The excision repair deficiency sensitized the cells to killing by HN2 and abolished mutation induction. Inactivation of RAD52 had no influence on the lethality of HN2 treatment but diminished the induced mutation frequency by 50% at all doses tested. DNA sequence analysis of HN2-induced SUP4-o mutations suggested that RAD52 contributed to the production of basepair substitutions at G·C sites. The rad52 defect appeared to alter the distribution of G·C → A·T transitions in SUP4-o relative to the distribution for the wild-type strain. This difference did not seem to be due to an effect of RAD52 on the relative fractions of HN2-induced transitions at localized (flanked by A·T pairs) or contiguous (flanked by at least one G·C pair) G·C sites but instead to an influence on the strand specificity of HN2 mutagenesis. In the repair-proficient strain, the transitions showed a small bias for sites having the guanine on the transcribed strand and this preference was eliminated by inactivation of RAD52.
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    Downstream activating sequence within the coding region of a yeast gene: specific binding in vitro of RAP1 protein (1992)
    Springer
    Molecular genetics and genomics 236 (1992), S. 65-75 
    Details
    ISSN: 1617-4623
    Keywords: Saccharomyces cerevisiae ; SRP1 ; Yeast downstream activating sequence ; RAP1/GRF1 binding sequence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Using a gel retardation assay, a protein factor that specifically interacts with a 33 by intragenic sequence of the highly expressed and glucose-inducible SRP1 gene of Saccharomyces cerevisiae has been detected. This binding site is located in a transcribed region and within the open reading frame (positions +710 to +743 relative to the first base of the initiation codon). A mutant strain carrying a deletion of this binding site showed a dramatic decrease in steady-state levels of SRP1 transcripts. This decline is not the result of a decrease in mRNA stability, since expression of hybrid genes in which the SRP1 promoter was replaced by the heterologous CYC1 promoter was not affected by the binding site deletion. These findings suggest that the 33 by sequence contains a cis-acting downstream activating element which is involved in the transcriptional activation of the SRP1 promoter. Sequence comparisons showed similarities between a site located within the 33 by sequence and the high-affinity consensus binding site of the RAP1/GRF1 (also named TUF) factor and methylation interference experiments confirmed that this site was involved in the protein-DNA interaction. Both the results of competition experiments with upstream activating sequences of ribosomal protein genes (UASrpg), which are targets for RAP1 binding, and determination of the apparent molecular weight of the affinity-purified DNA-binding protein indicated that RAP1 factor recognized the SRP1 33 by element. The 33 by sequence was found to be unable to provide UAS activity when placed upstream of the TATA box and transcription start site.
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    Temperature sensitivity of the cdc9-1 allele of Saccharomyces cerevisiae DNA ligase is dependen on specific combinations of amino acids in the primary structure of the expressed protein (1992)
    Springer
    Molecular genetics and genomics 232 (1992), S. 332-334 
    Details
    ISSN: 1617-4623
    Keywords: Saccharomyces cerevisiae ; cdc9-1 ; DNA ligase ; DNA sequence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In this study we present the characterization of the temperature-sensitive mutant allele cdc9-1 encoding DNA ligase, of Saccharomyces cerevisiae strain A364A by DNA sequencing. Comparison with the published wild-type sequence from strain SKI revealed 13 nucleotide exchanges between these two sequences, which are derived from non-isogenic genetic backgrounds. Only four of these changes, distributed over the whole coding region, lead to amino acid exchanges in the protein chain. Our analysis of the sequence of the wild-type CDC9 allele from strain A364A revealed differences from the isogenic cdc9-1 allele in only two nucleotides: one silent change and one leading to a single amino acid exchange. The latter is therefore responsible for the temperature-sensitive phenotype. A mosaic protein, in which a region carrying this amino acid exchange has been inserted in place of the corresponding part of CDC9 from the non-isogenic strain SKI, is not temperature sensitive. The exchange of a longer stretch of DNA leading to atteration of three amino acids of the protein compared with the original sequence of SKI is required to obtain a temperature-sensitive DNA ligase in this strain, while in strain A364A a single amino acid change is sufficient for expression of a temperature-sensitive protein.
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    The cauliflower mosaic virus 35S promoter is regulated by cAMP in Saccharomyces cerevisiae (1992)
    Springer
    Molecular genetics and genomics 235 (1992), S. 365-372 
    Details
    ISSN: 1617-4623
    Keywords: Saccharomyces cerevisiae ; CaMV 35S promoter ; cAMP ; Transcription factors ; Heterologous expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The cauliflower mosaic virus 35S promoter confers strong gene expression in plants, animals and fission yeast, but not in budding yeast. On investigating this paradox, we found that in budding yeast the promoter acts through two domains. Whereas the upstream domain acts as a silencer, the downstream domain couples expression to the nutritional state of the cells via the RAS/cAMP pathway. Point mutations indicate that two boxes with similarity to the cAMP regulated element (CRE) of mammalian cells mediate this response. Gel retardation assays show that, in both yeast and plant protein extracts, factors bind to this promoter element. Therefore, transcriptional activation appears to be highly conserved at the level of transcription factors and specific DNA target elements in eukaryotes. This offers new ways to investigate gene regulation mechanisms of higher eukaryotes, which are not as amenable to genetic analysis as yeast.
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    Nitrogen and phosphorus cycling in relation to stand age of Ecucalyptus regnans F. Muell (1992)
    Springer
    Plant and soil 142 (1992), S. 157-166 
    Details
    ISSN: 1573-5036
    Keywords: Acacia ; Eucalyptus regnans ; decomposition ; litterfall ; nitrogen ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The N and P contents of the litter layer and the return of these nutrients in litterfall were measured in seven stands of Mountain Ash (Eucalyptus regnans) ranging in age from 5 years to about 250 years. Both annual litterfall and nutrient return were correlated with stand basal area and were high compared with other productive eucalypt forests. In contrast, the fall of dead eucalypt leaves was constant with stand age, demonstrating that sites are fully occupied at an early age. Similarly, amounts of N and P in total leaf fall (overstorey plus understorey) were constant with stand age, except for low amounts in the stand aged 40 years where Acacia spp., important fixers of atmospheric N, were not prevalent. The decomposition constant (k) of organic matter in the litter layer decreased with stand age, from 0.31 year-1 at age 5 years to 0.23 year-1 at age 250 years. These constants also applied to N and P, indicating a tight coupling between organic matter decomposition and release of these nutrients from litter. The litter layer released about 30 kg ha-1 of N at age 5 years, and about 70 kg ha-1 at age 80 years. These results are discussed in relation to growth of Mountain Ash following fire, and the subsequent retention and accumulation of N during stand development.
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    Soil phosphorus status, pH and the manganese nutrition of wheat (1992)
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    Plant and soil 145 (1992), S. 45-50 
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    ISSN: 1573-5036
    Keywords: acidity ; manganese ; pH ; phosphorus ; soil solution wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A pot experiment was carried out in order to test the hypothesis that manganese nutrition of wheat was dependent on the phosphorus status of soil as well as on its pH and manganese status. An arable mineral soil whose lime and phosphorus status had been massively adjusted more than 18 years previously was compared with identical soil not so adjusted. Wheat plants were grown to maturity in these soils. Analyses were carried out on both soil and plant samples at intervals. Data for soil pH, soil solution concentrations of manganese and phosphorus, plant dry weight and tissue concentrations of manganese and phosphorus are presented. Concentrations of manganese were depressed in leaf tissue of plants from limed soils and also in high phosphorus soils. The depressed values for limed treatments were explained in terms of depressed soil solution manganese concentrations resulting from elevated pH. The results for high phosphorus soils could not be related to soil solution composition. It was suggested that high soil phosphorus resulted in elevated plant phosphorus which interfered in the uptake and/or translocation of manganese.
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    A review of phosphorus efficiency in wheat (1992)
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    Plant and soil 146 (1992), S. 163-168 
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    ISSN: 1573-5036
    Keywords: genetic variability ; NIR ; ploidy ; phosphorus ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract More efficient utilization of phosphorus by wheat plants is needed to extend the useful life of the phosphate reserves in the world, to reduce the cost of producing crops, and to improve the value of the grain and the straw produced. In this paper definitions of efficient use of phosphorus by wheat are reviewed, genotypic variation in phosphorus efficiency is reported, some consequences of breeding for greater efficiency are discussed, and ways to select more efficient genotypes are suggested.
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    Influence of plant nutrient concentration on growth rate: Use of a nutrient interruption technique to determine critical concentrations of N, P and K in young plants (1992)
    Springer
    Plant and soil 142 (1992), S. 221-233 
    Details
    ISSN: 1573-5036
    Keywords: critical concentration ; deficiency ; diagnosis ; growth rate ; lettuce ; luxury consumption ; nitrogen ; nitrate ; nutrient requirement ; petiole sap ; phosphorus ; phosphate ; potassium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A method is described for determining the way in which growth rate varies with plant nutrient concentration using a simple nutrient interruption technique incorporating only 2 treatments. The method involves measuring the changes in growth and nutrient composition of otherwise well-nourished plants after the supply of one particular nutrient has been withheld. Critical concentrations are estimated from the relationship between the growth rate (expressed as a fraction of that for control plants of the same size which remained well-nourished throughout) and the concentration of the growth-limiting nutrient in the plants as deficiency developed. Trials of the method using young lettuce plants showed that shoot growth rate was directly proportional to total N (nitrate plus organic N) concentration, and linearly or near-linearly related to K and P concentration over a wide range; the corresponding relationship for nitrate was strongly curvi-linear. Critical concentrations (corresponding to a 10% reduction in growth rate) determined from these results were similar to critical values calculated from models derived from field data, but were generally higher than published estimates of critical concentration (based on reductions in shoot weight) for plants of a similar size. Reasons for these discrepancies are discussed. Nitrate, phosphate or potassium concentrations in sap from individual leaf petioles were highly sensitive to changes in shoot growth rate as deficiency developed, with the slope of the relationships varying with leaf position, due to differences both in their initial concentration and in the rates at which they were utilized in individual leaves. Each nutrient was always depleted more quickly in younger leaves than in older ones, providing earlier evidence of deficiency for diagnostic purposes. Although the plants were capable of accumulating nitrate, phosphate and potassium well in excess of that needed for optimum dry matter production during periods of adequate supply, the rate of mobilization of these reserves was insufficient to prevent reductions in growth rate as the plants became deficient. This brings into question the validity of the conventional concept that luxury consumption provides a store of nutrients which are freely available for use in times of shortage. The implications of these results for the use of plant analysis for assessing plant nutrient status are discussed.
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    Inability to solubilize phosphate in limestone soils—key factor controlling calcifuge habit of plants (1992)
    Springer
    Plant and soil 145 (1992), S. 65-70 
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    ISSN: 1573-5036
    Keywords: calcifuge plants ; phosphorus ; deficient absorption ; Deschampsia flexuosa ; Jasione montana ; Rumex acetosella ; Silene rupestris
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Germination, seedling establishment and growth of calcifuge plants in Swedish limestone soils of Archean and Ordovician age were studied. As previously demonstrated for Viscaria vulgaris, establishment of Rumex acetosella and Silene rupestris did not succeed unless CaHPO4 (at the rate of 10 mmol dm-3 of soil) was supplied. Growth of Deschampsia flexuosa was enhanced by phosphate addition, whereas establishment success of Jasione montana was poor, regardless of phosphate treatment. Establishment and growth in an acidic gneiss soil, used as a reference for the species studied, was good. Total, total inorganic, exchangeable, and soil solution P were considered in all soils and treatments. It is proposed that the calcifuge behaviour of plants is quite often caused by inability to solubilize the native phosphate of limestone soils.
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    Can maize cultivars with low mineral nutrient concentrations in the grains help to reduce the need for fertilizers in third world countries? (1992)
    Springer
    Plant and soil 146 (1992), S. 227-231 
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    ISSN: 1573-5036
    Keywords: cultivars ; grains ; maize ; nitrogen ; phosphorus ; potassium ; tropical climate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract An earlier study revealed considerable genotypic variation in grain N, P and K concentrations (GNC, GPC and GKC, respectively) in tropical maize. The expression of varietal differences in GNC, GPC and GKC, however, may depend on environmental conditions such as the N status of the soil. Two tropical maize hybrids (Suwan 2301 and CP 1) with comparable yielding capacity, but contrasting GNCs, GPCs and GKCs, were therefore grown at four levels of N in a field experiment at Farm Suwan (Thailand, latitude 14.5°N). Suwan 2301 exhibited a higher GNC than did CP 1 at all rates of N, but large differences in GPC and GKC were found only at high N fertilization. This was obviously due to individual grain yield responses of the cultivars to increasing rates of N fertilizer, demonstrating that grain nutrient concentrations are, at least in part, functions of the amount of grain carbohydrates which dilute a genetically and environmentally fixed amount of grain P and K. As compared to Suwan 2301, CP 1 accumulated less N, P and K in the grains at almost all levels of N fertilization, confirming our hypothesis that the cultivation of maize genotypes with low grain mineral nutrient concentrations may help third-world cash-crop farmers to reduce the need for scarce and costly mineral fertilizers. This finding has to be verified at reduced availability of soil −P, −K, and water.
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    Effects of phytoplankton on the elemental composition (C, N, P) of suspended particulate material in the lower river Rhine (1992)
    Springer
    Hydrobiologia 235-236 (1992), S. 479-489 
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    ISSN: 1573-5117
    Keywords: River Rhine ; phytoplankton ; suspended material ; carbon ; nitrogen ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The spatial and temporal distribution of element concentrations were monitored together with chlorophyll a as an indicator of algal density to assess the effect of phytoplankton on the elemental composition (C, N, P) of suspended materials in the lower Rhine. The high concentrations of particulate C, N and P in the river were found to decrease in the delta and to increase again in the estuarine turbidity zone. Phytoplankton blooms increased the concentrations of particulate C, N, and P significantly in the upstream part of the river. In summer 1989, 15–65% of the particulate C and 20–75% of the particulate N were attributable to phytoplankton. Together with published data these observations indicate that in eutrophic rivers, the input of organic materials from the catchment is strongly modified and supplemented by in situ growth of phytoplankton. During seaward transport the phytoplankton and the particulate elements disappeared from the river water concomitantly with the suspended matter, indicating an increased retention of these elements due to sedimentation. In contrast, soluble ammonia, nitrite and phosphate increased in the tidal reaches of the river because of local input in the harbour and city of Rotterdam and because of mineralization. Therefore the total nutrient load of the Rhine estimated at the German/Dutch border does not reflect the actual input into the sea.
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    Iron:phosphorus ratio in surface sediment as an indicator of phosphate release from aerobic sediments in shallow lakes (1992)
    Springer
    Hydrobiologia 235-236 (1992), S. 731-743 
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    ISSN: 1573-5117
    Keywords: Lakes ; sediments ; iron ; phosphorus ; phosphate release
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Analysis of Danish lakes showed that both mean winter and mean summer concentrations of lake water total phosphorus in the trophogenic zone correlated negatively with the total iron to total phosphorus ratio (Fe:P) in surface sediments. No correlation was found between the water total phosphorus concentration and either the sediment phosphorus concentration alone or with sediment calcium concentration. The increase in total phosphorus from winter to summer, which is partly a function of net internal P-loading, was lowest in lakes with high Fe:P ratios in the surface sediment. A study of aerobic sediments from fifteen lakes, selected as representative of Danish lakes with respect to the sediment Fe and phosphorus content, showed that the release of soluble reactive phosphorus was negatively correlated with the surface sediment Fe:P ratio. Analysis of phosphate adsorption properties of surface sediment from 12 lakes revealed that the capability of aerobic sediments to buffer phosphate concentration correlated with the Fe:P ratio while the maximum adsorption capacity correlated with total iron. Thus, the Fe:P ratio may provide a measure of free sorption sites for orthophosphate ions on iron hydroxyoxide surfaces. The results indicate that provided the Fe:P ratio is above 15 (by weight) it may be possible to control internal P-loading by keeping the surface sediment oxidized. Since the Fe:P ratio is easy to measure, it may be a useful tool in the management of shallow lakes.
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    Biogeochemistry of manganese- and iron-rich sediments in Toolik Lake, Alaska (1992)
    Springer
    Hydrobiologia 240 (1992), S. 45-59 
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    ISSN: 1573-5117
    Keywords: arctic lakes ; trace metals ; lake sediments ; manganese ; iron ; phosphorus ; sediment-water flux ; diagenesis ; Toolik Lake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The sediments within Toolik Lake in arctic Alaska are characterized by extremely low rates of organic matter sedimentation and unusually high concentrations of iron and manganese. Pore water and solid phase measurements of iron, manganese, trace metals, carbon, nitrogen, phosphorus, and sulfur are consistent with the hypothesis that the reduction of organic matter by iron and manganese is the most important biogeochemical reaction within the sediment. Very low rates of dissolved oxygen consumption by the sediments result in an oxidizing environment at the sediment-water interface. This results in high retention of upwardly-diffusing iron and manganese and the formation of metal-enriched sediment. Phosphate in sediment pore waters is strongly adsorbed by the metal-enriched phases. Consequently, fluxes of phosphorus from the sediments to overlying waters are very small and contribute to the oligotrophic nature of the Toolik Lake aquatic system. Toolik Lake contains an unusual type of lacustrine sediment, and in many ways the sediments are similar to those found in oligotrophic oceanic environments.
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    Sources, concentrations and characteristics of organic matter in softwater lakes and streams of the Swedish forest region (1992)
    Springer
    Hydrobiologia 229 (1992), S. 23-41 
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    ISSN: 1573-5117
    Keywords: TOC ; COD ; humic ; colour ; Secchi ; phosphorus ; carbon ; permanganate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 18 Swedish forest lakes covering a wide range of dystrophy were studied in order to quantify and characterize the organic matter in the water with respect to origin (allochthonous or autochthonous), physical state (particulate or dissolved) and phosphorus content. Samples were collected repeatedly during a two-year period with unusually variable hydrological conditions. Water from three different depths and from tributaries was analysed with standard monitoring methods, including water colour, Secchi disk transparency, total organic carbon (TOC), CODCr, CODMn, total phosphorus and molybdate reactive phosphorus. Interrelationships were used to compare different methods and to assess the concentration and composition of organic matter. It is estimated that in remote softwater lakes of the Swedish forest region, autochthonous carbon is typically 〈 5 g m−3. Most lakes in this region receive significant amounts of humic matter originating from coniferous forest soils or peatland in the catchment area. In most humic lakes with a water colour of ≥ 50 g Pt m−3, more than half of the organic carbon in the surface water is of allochthonous origin, and in polyhumic lakes (〉 200 g Pt m−3) the proportion can exceed 90%. Secchi depth readings were related similarly to organic matter from both sources and provided good estimates of TOC with a single optical measurement. Water colour was used to distinguish allochthonous and autochthonous matter. High concentrations of phosphorus were found in humic waters, most of it being molybdate reactive, and probably associated with humic matter rather than as dissolved free inorganic forms. CODMn yielded only 25–60% of TOC and appears to include mainly truly dissolved substances of low molecular weight.
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    Nutrient loading and drainage channel response in a ricefield system (1992)
    Springer
    Hydrobiologia 230 (1992), S. 193-200 
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    ISSN: 1573-5117
    Keywords: nitrogen ; phosphorus ; ricefield system ; drainage channels ; mediterranean Deltas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nitrogen and phosphorus released into the water of a main drainage channel in the Ebro Delta was measured during a period of rice cultivation. An increase in total nitrogen and phosphorus in its different forms in accordance with the increase in cultivated area drained was observed. A significant correlation between the release of nutrients into the water and the nutrient load, for both nitrogen and phosphorus, if we consider the release of nutrients per unit of length of the channel and increased total phosphorus content of the water that flows through it during the period of rice cultivation. Physical and chemical changes in the water as a result of ricefield metabolism may explain the differences observed in nitrogen and phosphorus cycles between Ebro and Rhône Deltas, two mediterranean deltaic systems where a large area with similar drainage system is used for rice cultivation.
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    Changes in water quality in Lake Päijänne following decrease of effluent load from the pulp and paper industry in 1969–1989 (1992)
    Springer
    Hydrobiologia 243-244 (1992), S. 395-403 
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    ISSN: 1573-5117
    Keywords: Lake Päijänne ; pulp mills ; BOD ; phosphorus ; water quality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Lake Päijänne, the second largest lake in Finland, has been seriously polluted since the 1960s due to the effluents from pulp and paper mills, notably the Äänekoski sulphate and sulphite pulp mills situated about 50 km north of the lake, and the sulphite pulp mill and paper mills of Jämsänkoski and Kaipola on Central Lake Päijänne. A sulphite lye evaporation and combustion plant installed at the Jämsänkoski sulphite pulp mill in 1969 reduced the organic pollution of Central Päijänne. Lignin concentration decreased and the oxygen balance improved. The sulphite pulp mill was closed in 1981 and replaced by a thermo-mechanical pulp mill. Eutrophication is the main threat to water quality in Central Lake Päijänne at present. A significant improvement in the water quality, especially in oxygen balance, was achieved in the watercourse of Äänekoski and in Northern Päijänne after replacement of the old sulphite and sulphate pulp mills at Äänekoski by a large sulphate pulp mill with a biological purification plant employing the activated sludge method. The BOD7-loading dropped from 46 to 3–4 t d−1, but the nutrient loading has not decreased sufficiently, and the Äänekoski watercourse and Northern Päijänne are still eutrophic.
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    Bioassay for phosphate demand in phytoplankton from acidified lakes: Lake Njupfatet, an example of phosphate deficiency induced by liming (1992)
    Springer
    Hydrobiologia 246 (1992), S. 99-110 
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    ISSN: 1573-5117
    Keywords: acid lakes ; ATP ; in situ enclosures ; liming ; phosphatases ; phosphorus ; phytoplankton community
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A bioassay was developed, involving steady-state ATP level determinations, for estimation of phosphate demand and deficiency in natural phytoplankton communities. The studies were performed on phytoplankton from the moderately acidified Lake Njupfatet in central Sweden before and after liming. Phytoplankton samples from in situ enclosure experiments with low-dose enrichments of nitrate and phosphate and removal of large (〉 100 µm) zooplankton and from the lake water were collected. The phytoplankton were concentrated by through-flow centrifugation and post-cultured in the laboratory with or without the addition of phosphate. A relative increase in the ATP:chlorophyll a ratio after the phosphate treatment as compared to samples without phosphate enrichment was found to be a highly reproducible indicator of phosphate deficiency in the natural phytoplankton population. In contrast, the absolute ATP:chlorophyll a ratio varied substantially between different sampling occasions. No phosphate deficiency was detected in phytoplankton from the acidic lake or from fertilized in situ enclosures. However, phytoplankton from in situ enclosures without added nutrients showed evidence of phosphate limitation after 21 days incubation. Also, the phytoplankton community developed a significant phosphate deficiency the summer after lake liming. The results from the ATP analyses are compared with chemical data of the lake water, phytoplankton community structure and phosphatase activities in the lake before and after liming. The average total biomass of phytoplankton and the average Tot-P measured during May to September decreased with appr. 30% after liming while Tot-N was essentially unaffected and the phosphatase activities increased by 1000–2000%.
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    Regeneration of inorganic phosphorus and nitrogen from decomposition of seston in a freshwater sediment (1992)
    Springer
    Hydrobiologia 228 (1992), S. 71-81 
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    ISSN: 1573-5117
    Keywords: nutrient regeneration ; phosphorus ; nitrogen ; sediment ; lakes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The mineralization of phosphorus and nitrogen from seston was studied in consolidated sediment from the shallow Lake Arreskov (July and November) and in suspensions without sediment (July). In the suspension experiment, phosphorus and nitrogen were mineralized in the same proportions as they occurred in the seston. During the 30 days suspension experiment, 47 and 43% of the particulate phosphorus and nitrogen, respectively, was mineralized with constant rates. Addition of seston to the sediment had an immediate enhancing effect on oxygen uptake, phosphate and ammonia release, whereas nitrate release decreased due to denitrification. The enhanced rates lasted for 2–5 weeks, while the decrease in nitrate release persisted throughout the experiment. The increase in oxygen uptake (equivalent to 21% of the seston carbon) was, however, only observed in the July experiment. The release of phosphorus and nitrogen from seston decomposing on the sediment surface differed from the suspension experiments. Thus, between 91 and 111% of the phosphorus in the seston was released during the experiments. Due to opposite directed effects on ammonium and nitrate release, the resulting net release of nitrogen was relatively low. A comparison of C/N/P ratios in seston, sediment and flux rates indicated that nitrogen was mineralized faster than phosphorus and carbon. Some of this nitrogen was lost through denitrification and therefore not measurable in the flux of inorganic nitrogen ions. This investigation also suggests that decomposition of newly settled organic matter in sediments have indirect effects on sediment-water exchanges (e.g. by changing of redox potentials and stimulation of denitrification) that modifies the release of mineralized phosphate and nitrogen from the sediment.
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    The influence of flushing on nutrient dynamics, composition and densities of algae and transparency in Veluwemeer, The Netherlands (1992)
    Springer
    Hydrobiologia 233 (1992), S. 187-196 
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    ISSN: 1573-5117
    Keywords: eutrophication ; lake restoration ; flushing ; Veluwemeer ; algal species ; transparency ; phosphorus ; nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Total phosphorus and chlorophyll decreased significantly after reduction of the external phosphorus loading and the start of flushing Veluwemeer with polder water in 1979. Flushing of Veluwemeer has had a large impact on nutrient dynamics. Especially in the first winter, dilution was the main cause of changes in water quality. On a longer term the increase of the inactivation of phosphorus in sediments is important. Oscillatoria agardhii has been brought to the margins of its habitat. Three successive cold winters were an additional causal factor in the disappearance of Oscillatoria agardhii and the dominance of diatoms and green algae from 1985 onwards. Due to higher detritus and inorganic suspended matter concentrations transparency increased less than expected. Since 1985 chlorophyll only contributes for a small percentage to the transparency. In the present situation further improvement of the water quality of Veluwemeer is questionable, as the phosphorus concentration in the lake and the polder water is almost the same. Therefore it is recommanded to shift flushing operations, at least in the winter period, from Veluwemeer towards Wolderwijd.
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    Fixation of phosphorus in lake sediments using iron(III)chloride: experiences, expectations (1992)
    Springer
    Hydrobiologia 233 (1992), S. 211-212 
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    ISSN: 1573-5117
    Keywords: eutrophication ; lake restoration ; phosphorus ; sediments ; internal loading ; chemomanipulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract After a reduction of the external phosphorus loading to a lake, an internal loading from the sediments may delay the improvement of the water quality. The accepted method to combat internal loading is careful dredging of the upper sediment layers (Cooke et al., 1986), but this method is costly and time consuming. Addition of phosphorus binding agents to the sediments might offer an alternative. In the Netherlands the use of aluminum compounds, the most common phosphorus binding agent, for water quality improvement purposes is not favoured. Therefore a sediment treatment with a solution of iron(III)chloride was tested. Iron was chosen because it is considered to be a natural binder of phosphate. 100 g m−2 of Fe3+ were added to the sediments of the shallow (1.75 m average depth) and eutrophic Lake Groot Vogelenzang (The Netherlands) in October and November 1989. The iron(III)chloride solution was diluted 100 times with lake water and mixed with the surface sediments with a water jet. Following the addition the concentrations of total phosphorus (Fig. 1), chlorophyll-a and suspended solids decreased. This improvement of the water quality lasted for three months. After this time the total phosphorus concentration increased again, but remained at a lower level than in spring and summer of 1989. The phosphorus release rate from the sediments as measured from intact sediment cores decreased from 4 to 1.2 mg P m−2 d−1 (n = 5), and the bioavailability of the sediment phosphorus, as measured with bioassays, decreased from 34 to 23% (n = 5) shortly after the treatment. One year after the treatment the release rate was increased to 3 mg P m−2 d−1 (n = 5). Before treatment, the lake was thought to have a residence time of over one year. However, the chloride added to the lake disappeared according to a dilution rate of 0.03 d−1 or a retention time of about 35 days. A high external loading due to rapid flushing with phosphorus-rich water from surrounding lakes possibly prevented a more durable improvement in water quality. Another possibility is that the iron addition has lost its phosphate binding capacity due to reduction or binding with other anions like carbonate or sulphide. Therefore the suitability of the method to reduce internal loading and especially the long term availability of added iron to bind phosphorus needs additional proof. The treatment of the 18 ha area of Lake Groot Vogelenzang took three weeks. The operational costs were about US$ 125000. This is fast and cheap compared to dredging. Application of the technique is limited to those cases where the sediments are not polluted with micro-pollutants and the water depth need not be increased.
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    Phosphorus eutrophication in the SW Frisian lake district 1. Monitoring and assessment of a dynamic mass balance model (1992)
    Springer
    Hydrobiologia 233 (1992), S. 259-270 
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    ISSN: 1573-5117
    Keywords: eutrophication ; lakes ; phosphorus ; chloride ; loading ; dynamic mass balance model ; sensitivity analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In 1984 a frequent monitoring programme was started in the hypertrophic S.W. Frisian lake district, with emphasis on total phosphorus (TP) and chloride (Cl−). The main objectives of the project were: to quantify the phosphorus flows, to gain insight in the process of eutrophication, and to simulate management scenarios. The seasonal variability in the lakes is due mainly to the man-made hydrology: reception of humic-rich polder water in wet periods (winter) and inlet of chloride-rich Usselmeer water in dry periods (summer). The yearly means of TP concentrations in the lakes (Tjeukemeer, Groote Brekken and Slotermeer) ranged from 0.23 to 0.29 mg l−1. However, much higher concentrations (0.9 mg l−1) were found in periods with high inflow of polder water. The simulations with a mass balance showed an acceptable similarity between measured and simulated concentrations of TP as well as of Cl−. Chloride was modelled to verify the accuracy of a hydrodynamic model. A sensitivity analysis of the apparent settling rate in the P model showed that sensitivity was lowest in simulations of Groote Brekken and highest in simulations of Slotermeer, the difference being attributable to the influence of the water residence time. The model was found to be appropriate for simulating management scenarios.
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    A mathematical model of the phosphorus cycle in Lake Loosdrecht and simulation of additional measures (1992)
    Springer
    Hydrobiologia 233 (1992), S. 119-136 
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    ISSN: 1573-5117
    Keywords: model ; simulation ; eutrophication ; phosphorus ; P/C ratio ; lake ecosystem
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The phosphorus cycle in the ecosystem of the shallow, hypertrophic Loosdrecht lakes (The Netherlands) was simulated by means of the dynamic eutrophication model PCLOOS. The model comprises three algal groups, zooplankton, fish, detritus, zoobenthos, sediment detritus and some inorganic phosphorus fractions. All organic compartments are modelled in two elements, carbon and phosphorus. Within the model system, the phosphorus cycle is considered as completely closed. Carbon and phosphorus are described independently, so that the dynamics of the P/C ratios can be modelled. The model has been partly calibrated by a method based on Bayesian statistics combined with a Range Check procedure. Simulations were carried out for Lake Loosdrecht for the periods before and after the restoration measures in 1984, which reduced the external phosphorus loading to the lake from ca. 2 mgP m−2 d−1 to 1 mgP m−2 d−1. The model outcome was largely comparable withthe measured data. Total phosphorus has slowly decreased from an average 130 µgP l−1 to ca. 80 µgP l−1, but chlorophyll-a (ca. 150 µg 1−1, summer-averaged) and seston concentrations (8–15 mgC 1−1) hardly changed since the restoration measures. About two-thirds of the seston consisted of detritus, while the phytoplankton remained dominated by filamentous cyanobacteria. The P/C ratio of the seston decreased from ca. 1.0% to 0.7%, while the P/C ratios of zooplankton, zoobenthos and fish have remained constant and are much higher. The system showed a delayed response to the decreased phosphorus loading until a new equilibrium was reached in ca. five years. Major reasons for the observed resilience of the lake in responding to the load reduction are the high phosphorus assimilation efficiency of the cyanobacteria and the high internal recycling of phosphorus. A further reduction of nutrient loading, perhaps in combination with additional measures like biomanipulation, will be the most fruitful additional restoration measure.
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    Coupling between benthic biomass of Microcystis and phosphorus release from the sediments of a highly eutrophic lake (1992)
    Springer
    Hydrobiologia 235-236 (1992), S. 375-385 
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    ISSN: 1573-5117
    Keywords: Microcystis ; microbial activity ; sediment ; phosphorus ; internal loading
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Variations in microbial biomass and activity in the sediments of hypereutrophic Lake Vallentunasjön were followed during a period of 5 years. The data were compared to the calculated release of phosphorus from the sediments during the same period. A strong co-variation was found between biomass of Microcystis, heterotrophic bacterial activity in the sediments and internal phosphorus loading. These parameters exhibited mainly a declining trend during the investigation period. A pronounced stability of the sediment chemistry, including the fractional composition of the sediment phosphorus, during the studied period indicates that microbial activity affected the phosphorus release from the sediments. Calculations of the percentage of sediment bacteria that was associated to the mucilage of Microcystis colonies imply, together with the specific bacterial production, that Microcystis in the sediment stimulates bacterial production. In the highly phosphorus-saturated sediments of Lake Vallentunasjön this would ultimately lead to an increased release of phosphorus from the sediment. Lake Vallentunasjön does not follow the common pattern of recovery after reduction of external phosphorus loading. The large biomasses and long survival of Microcystis in the sediment are probably important reasons for the delayed recovery of the lake.
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    The turnover of river-transported iron, phosphorus and organic carbon in the Öre estuary, northern Sweden (1992)
    Springer
    Hydrobiologia 235-236 (1992), S. 585-596 
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    ISSN: 1573-5117
    Keywords: estuary ; iron ; phosphorus ; organic carbon ; aggregation ; sedimentation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The turnover of iron, phosphorus and organic carbon was followed in the Öre Estuary, northern Sweden, during the spring flood periods of 1989 and 1990. River-supplied material rapidly sediments out of the water column and is primary deposited within the estuary. The removal of iron and phosphorus is complete, with the calculated sedimentation exceeding the total amounts of particulate and dissolved iron and phosphorus supplied by the river. Aggregation of dissolved or colloidal iron-phosphate complexes due to increasing salinity and pH in combination with adsorption on rapidly sedimentating inorganic particles is suggested to explain this estuarine filter effect. Organic carbon is only affected by aggregation and sedimentation to a minor extent.
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    Phosphorus transformations in the epilimnia of small humic forest lakes (1992)
    Springer
    Hydrobiologia 243-244 (1992), S. 105-111 
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    ISSN: 1573-5117
    Keywords: phosphorus ; transformations ; humic forest lake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Research on epilimnetic phosphorus transformations in lakes had led to the establishment of a generalised picture which is promoted in reviews and textbooks. However, it would be wrong to believe that this established view can be applied to all lakes. Certainly the transformations of phosphorus in the summer epilimnia of small, coloured, humic forest lakes in southern Finland show features which deviate markedly from the generally accepted paradigm. (1) The plankton appears to be limited simultaneously by P and N rather than being strongly P limited. (2) Particulate P is typically a rather small fraction of the total P. (3) Molybdate reactive P may be a large part of the total P, although much of this MRP is not free orthophosphate, especially in highly humic lakes. (4) Turnover times for PO4-P are normally long (50–1000 minutes); turnover times appear to be longer in highly humic lakes. (5) Added 32 PO4 passes rapidly to macrozooplankton, apparently with rapid turnover of zooplankton phosphorus. (6) Sedimentation of phosphorus from the typically shallow epilimnion appears high, but may be partially compensated by biological retrieval of phosphorus from the phosphorus-rich hypolimnion.
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    Phytoplankton and zooplankton community structure after nutrient additions to the oligotrophic Lake Hecklan, Sweden (1992)
    Springer
    Hydrobiologia 243-244 (1992), S. 147-155 
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    ISSN: 1573-5117
    Keywords: fertilization ; phosphorus ; nitrogen ; phytoplankton ; zooplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Lake Hecklan, in central Sweden, was fertilized with phosphorus and nitrogen during thermal stratification (late May-early Oct) 1984–1987. The nutrient additions were relatively small and raised the total phosphorus concentrations from 6 to 10 µg l−1. The working hypothesis was that this moderate increase in the phosphorus concentration could increase the phytoplankton biomass without adverse changes in the planktonic community structure. The fertilization increased the phytoplankton biomass from 0.1 to a maximum of 2 mm3 l−1. Chrysophyceae and Cryptophyceae dominated throughout the experimental period. Thus, the phytoplankton composition remained typical for a Swedish forest lake and provided a potential for increased zooplankton growth. An increased growth of zooplankton was indicated by increased biomass of Cladocera and Copepoda in 1984 and 1985, and by increased fecundity of herbivorous zooplankton.
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    Mass balance models for elongated lakes (1992)
    Springer
    Hydrobiologia 243-244 (1992), S. 341-349 
    Details
    ISSN: 1573-5117
    Keywords: mass balance ; modelling ; phosphorus ; sedimentation ; CSTR ; PFR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Mass balance models for elongated lakes have been developed. In these models particular attention is paid to the hydraulic description of the lake and to the description of net sedimentation. The hydraulic description is a linear combination of CSTR and PFR, with a coefficient regulating the degree of mixing. The PFR description was modified so that also additional input along the lake can be considered. Net sedimentation is described either as a first order or a second order reaction. Both voluminal and areal sedimentation is possible in the models. The models were tested against phosphorus balance data for two Finnish lakes. Lake Haukivesi and Lake Päijänne. In both lakes the PFR model with additional input together with second order net sedimentation gave the best fit to observations. The values of the sedimentation coefficients are not universal but vary from lake to lake. They are also dependent on the hydraulic description used in the model. There is a critical point for the monitoring of the lake at which measurements give the same sedimentation coefficient regardless of the hydraulic description.
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    Nutrient dynamics in the floodplain ponds of the Paraná River (Argentina) dominated by the water hyacinth Eichhornia crassipes. (1992)
    Springer
    Biogeochemistry 17 (1992), S. 85-121 
    Details
    ISSN: 1573-515X
    Keywords: nitrogen fixation ; phosphorus ; internal loading ; water hyacinth ; floodplain ; Paraná ; flood-pulse hypothesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Some aspects of nutrient status and dynamics prevailing during low and high water conditions in the fringing floodplain ponds of the Paraná River dominated by the floating macrophyte Eichhornia crassipes are described. During summertime low water conditions, low DIN:DRP ratios (0.16–1.0) and low DIN (0.5–4.8 μmol.liter−1) in the root-zone of the floating meadows suggest that macrophyte growth is limited by nitrogen. DRP concentrations appear to be controlled more by abiotic sorption-dissolution than by biological reactions. Preflood nutrient fluxes from the sediments, as estimated from porewater profiles, show that a minimum of 1.19 and 0.38 mmol.m−2.d−1 of DIN and DRP were regenerated from the sediments, respectively. Heterotrophic N2 fixation is primarily associated with decaying litter (0.4 to 3.2 μmolN2.g−1.d−1). Nutrient recycling from sediments and meadow-litter, and heterotrophic N2 fixation (1.4 mmolN.m−2.d−1) appear sufficient to sustain high floating macrophyte productivity for long periods of time, without invoking large inputs from the river. The high water and early isolation periods are characterized by a very dynamic behavior of DIN, reflecting marked imbalances between N supply and demand by the biota. After hydrologic isolation of the ponds, DIN rapidly decreases to undetectable levels and stays low for the following 3 weeks, presumably as a result of high demand by phytoplankton and sediment bacteria. DIN increases again to high values 3–8 weeks after the flood, following the re-establishment of NH4 + fluxes from the sediments. Compared to DIN, DRP concentrations remain relatively high and change little during and after the flood. Because of their small amplitude and short duration, floods do not appear to stimulate floating macrophyte production in the Paraná.
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    Effects of nitrogen: phosphorus supply ratios on nitrogen fixation in agricultural and pastoral ecosystems (1992)
    Springer
    Biogeochemistry 18 (1992), S. 19-35 
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    ISSN: 1573-515X
    Keywords: Dinitrogen fixation ; nitrogen ; phosphorus ; competition ; legumes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract An analysis of data compiled from the literature confirms a strong inverse relationship between annual rates of nitrogen fixation and the soil nitrogen content in agricultural and pastoral ecosystems. However, this inverse relationship is strongly modified by the rate of application of phosphorus fertilizer, which strongly influences the activities of both symbiotic and non-symbiotic nitrogen fixing organisms. In the case of symbiotic legumes, the response of N-fixation to N and P is in part a result of changes in legume dominance within the plant community. These results, as well as supporting data presented from a review of experiments on nitrogen fixation in a variety of other terrestrial and aquatic ecosystems, provide important support for the hypothesis that phosphorus availability is a key regulator of nitrogen biogeochemistry.
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    Soil nutrient dynamics in response to irrigation of a Panamanian tropical moist forest (1992)
    Springer
    Biogeochemistry 19 (1992), S. 1-25 
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    ISSN: 1573-515X
    Keywords: nitrogen ; phosphorus ; soil fertility ; tropical forest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract We measured concentrations of soil nutrients (0–15 and 30–35 cm depths) before and after the dry season in control and dry-season irrigated plots of mature tropical moist forest on Barro Colorado Island (BCI) in central Panama to determine how soil moisture affects availability of plant nutrients. Dry-season irrigation (January through April in 1986, 1987, and 1988) enhanced gravimetric soil water contents to wet-season levels (ca. 400 g kg−1 but did not cause leaching beyond 0.8 m depth in the soil. Irrigation increased concentrations of exchangeable base cations (Ca2+, Mg2+, K+, Na+), but it had little effect on concentrations of inorganic N (NH4 +C, NO3 − and S (SO4 2−). These BCI soils had particularly low concentrations of extractable P especially at the end of the dry season in April, and concentrations increased in response to irrigation and the onset of the rainy season. We also measured the response of soil processes (nitrification and S mineralization) to irrigation and found that they responded positively to increased soil moisture in laboratory incubations, but irrigation had little effect on rates in the field. Other processes (plant uptake, soil organic matter dynamics) must compensate in the field and keep soil nutrient concentrations at relatively low levels.
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    Genetic and cell biological aspects of the yeast vacuolar H+-ATPase (1992)
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    Journal of bioenergetics and biomembranes 24 (1992), S. 395-405 
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    ISSN: 1573-6881
    Keywords: Vacuolar H+-ATPase ; VMA genes ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract The yeast vacuolar proton-translocating ATPase is a member of the third class of H+-pumping ATPase. A family of this type of H+-ATPase is now known to be ubiquitously distributed in eukaryotic vacuo-lysosomal organelles and archaebacteria. NineVMA genes that are indispensable for expression of the enzyme activity have been cloned and characterized in the yeastSaccharomyces cerevisiae. This review summarizes currently available information on theVMA genes and cell biological functions of theVMA gene products.
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    Whole cell yeast biotransformations in two-phase systems: Effect of solvent on product formation and cell structure (1992)
    Springer
    Journal of industrial microbiology and biotechnology 10 (1992), S. 169-177 
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    ISSN: 1476-5535
    Keywords: l-Phenylacetyl carbinol ; Biotransformations ; Two-phase systems ; Whole cells ; Saccharomyces cerevisiae ; Cell structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary Biotransformation of benzaldehyde and pyruvate to (R)-phenylacetyl carbinol bySaccharomyces cerevisiae was investigated in two-phase aqueous-organic reaction media. With hexane as organic solvent, maximum biotransformation activity was observed with a moisture content of 10%. Of the organic solvents tested, highest biotransformation activities were observed with hexane and hexadecane, and lowest activities occurred with chloroform and toluene. Biocatalyst samples from biphasic media containing hexane, decane and toluene manifested no apparent cell structural damage when examined using scanning electron microscopy. In contrast, cellular biocatalyst recovered from two-phase systems containing chloroform, butylacetate and ethylacetate exhibited damage in the form of cell puncturing after different incubation periods. Phospholipids were detected in reaction media from biocatalytic systems which exhibited cell damage in electron micrographs. Phospholipid release was much lower in the two-phase systems containing toluene or hexane or in 100% aqueous biocatalytic system.
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    Influence of the curing of the killer phenotype inSaccharomyces cerevisiae wine strains on their fermentative behaviour (1992)
    Springer
    World journal of microbiology and biotechnology 8 (1992), S. 147-150 
    Details
    ISSN: 1573-0972
    Keywords: Curing ; fermentative behaviour ; killer ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Fermentative behaviour and cell growth have been studied in grape juice inoculated either with two killerSaccharomyces cerevisiae wild strains or with their Acridine Orange-cured isogenic counterparts. The number of viable cells/ml at the beginning of the fermentation, as well as during exponential growth, were higher in grape juices inoculated with the cured strains. The CO2 production, fermentative rate and ethanol and acetic acid production were also higher in the cured strains, particularly during the stage of active fermentation. These differences, however, were minimal at the end of the fermentations.
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    Production of higher alcohols, ethyl acetate, acetaldehyde and other compounds by 14Saccharomyces cerevisiae wine strains isolated from the same region (Salnés, N.W. Spain) (1992)
    Springer
    World journal of microbiology and biotechnology 8 (1992), S. 539-541 
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    ISSN: 1573-0972
    Keywords: Aroma ; compound ; Saccharomyces cerevisiae ; wine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Fourteen strains of the yeastSaccharomyces cerevisiae were isolated from three wineries in the Salnés wine region (N.W. Spain) at the three different periods of the natural fermentation. Each wild yeast was screened for production of acetaldehyde, ethyl acetate, isobutanol,n-propanol, amylic alcohol and other important enological compounds during laboratory scale fermentations of grape juice. After 25 days at 20°C, the analytical results evidenced variations in the production of acetaldehyde (from 13.1 to 24.3 mg/l), isobutanol (from 27.7 to 51.1 mg/l), amyl alcohols (from 111 to 183 mg/l) and ethyl acetate (from 19.3 to 43.7 mg/l). Although isolated from the same wine region, differences in the wine composition were observed depending on the particular yeast strain used for the vinification experiments.
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    The influence of tillage and cropping-intensity on cereal response to nitrogen, sulfur, and phosphorus (1992)
    Springer
    Nutrient cycling in agroecosystems 31 (1992), S. 15-19 
    Details
    ISSN: 1573-0867
    Keywords: Tillage ; crop rotation ; cereal grain ; wheat ; nitrogen ; sulfur ; phosphorus ; no-till
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Efficient fertilizer use is a prerequisite for achieving optimum crop yield while avoiding environmental contamination. Cereal response to nitrogen (N), sulfur (S), and phosphorus (P) were determined for 6 years under differing tillage [conventional-till (CT) vs. no-till (NT)] and intensity of cropping (cereal/fallow vs. cereal/cereal). Semidwarf white winter wheat (Triticum aestivum L.) alternated yearly with either fallow or spring cereal [barley (Hordeum vulgare L.) or spring wheat] on a Typic Haploxeroll soil in a 415 mm rainfall zone. Fertilizer treatments were no fertilizer (None), N only (N), N plus S (NS), and N plus S plus P (NSP). Average application rate, when applied, was 109 kg N, 18 kg S, and 11 kg P ha−1. Average cereal yield without fertilizer was 1.82 t ha−1. Nitrogen increased grain yield in 6 of 6, S in 4 of 6, and P in 3 of 6 years, with P and S response significant the remaining years at the 10% probability level. Average yield increases were 1.11 t ha−1 for N, 0.93 t ha−1 for S, and 0.47 t ha−1 for P. The NT/CT yield ratio was 0.60, 0.75, 0.93, and 0.95 with None, N, NS, and NSP addition, respectively, indicating that N and S deficiency were more severe in no-till. Limited increase in the NT/CT ratio with P addition indicated that P deficiency was less affected by tillage. Winter wheat always yielded less under NT than CT regardless of fertility, whereas spring cereals reached equality when fertilized with NSP. Annually-cropped wheat yielded 52, 67, 89, and 90% of wheat after fallow with None, N, NS, and NSP, respectively. Thus N and S, but not P, deficiency was more intense with increased frequency of cropping. Adequate fertility was a prime prerequisite for efficient yield in all systems.
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    An economic evaluation of a long-term experiment on phosphorus and manure amendments to sandy Sahelian soils: Using a stochastic dominance model (1992)
    Springer
    Nutrient cycling in agroecosystems 33 (1992), S. 193-202 
    Details
    ISSN: 1573-0867
    Keywords: manure ; Niger ; phosphorus ; Sahelian soils ; stochastic dominance framework
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Poor fertility status of sandy Sahelian soils represents a major constraint to cereal and legume production. Soil amendment options were evaluated, using a stochastic efficiency framework. Dominance analyses showed that in the presence of annual applications of 30 kg N ha−1 and 30 kg K ha−1, efficient soil amendment options comprise of either the annual application of 8.7 kg P ha−1 in the form of single superphosphates in combination with 5 tonnes manure ha−1 applied every three years or the annual application of 17.5 kg P ha−1 in the form of single superphosphates. Choice between these two efficient options depends on the availability of manure, deficiencies in sandy soils and farmer resource endowments.
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    Genetic identification of naturalSaccharomyces sensu stricto yeasts from Finland, Holland and Slovakia (1992)
    Springer
    Antonie van Leeuwenhoek 61 (1992), S. 237-243 
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    ISSN: 1572-9699
    Keywords: electrophoretic karyotyping ; genetics ; Saccharomyces bayanus ; Saccharomyces cerevisiae ; Saccharomyces paradoxus ; taxonomy ; yeast ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Genetic and karyotypic studies of naturalSaccharomyces sensu stricto yeasts from Finland, Holland and Slovakia revealed three wild sibling-species:Saccharomyces cerevisiae, Saccaromyces bayanus andSaccharomyces paradoxus.
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    Alterations in the cell wall ofSaccharomyces cerevisiae induced by the alpha sex factor or a mutation in the cell cycle (1992)
    Springer
    Antonie van Leeuwenhoek 61 (1992), S. 269-276 
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    ISSN: 1572-9699
    Keywords: Saccharomyces cerevisiae ; cell wall ; alpha-factor ; cdc mutant ; chitin ; glucan
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We performed experiments in parallel to study the rate of synthesis of cell wall polysaccharides and the activity of glycosyl transferases inSaccharomyces cerevisiae after arrest of acdc 28 mutant in G1 phase by either addition of alpha-factor or transfer to the non-permissive temperature. Both effectors brought about similar time-dependent increases in the rate of synthesis and deposition of the cell wall polysaccharides chitin, glucan and mannan. These changes in cell wall composition were accompanied by an increase in the specific activities of glucan and chitin synthetases. This increase was inhibited by cycloheximide suggesting that it representedde novo enzyme biosynthesis and not enzyme activation. Our data are consistent with the notion that both alpha-factor and thecdc 28 mutation affect the same stage-specific function that controls the temporal expression of glycosyl transferases.
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    Nuclear transport and nuclear pores in yeast (1992)
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    Antonie van Leeuwenhoek 62 (1992), S. 3-14 
    Details
    ISSN: 1572-9699
    Keywords: Saccharomyces cerevisiae ; nuclear pore complex ; nuclear transport ; nuclear localization sequence ; nucleoporins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The central features of nuclear import have been conserved during evolution. In yeast the nuclear accumulation of proteins follows the same selective and active transport mechanisms known from higher eukaryotes. Yeast nuclear proteins contain nuclear localization sequences (NLS) which are presumably recognized by receptors in the cytoplasm and the nuclear envelope. Subsequent to this recognition step, nuclear proteins are translocated into the nucleus via the nuclear pore complexes. The structure of the yeast nuclear pore complex resembles that of higher eukaryotes. Recently, the first putative components of the yeast nuclear import machinery have been cloned and sequenced. The genetically amenable yeast system allows for an efficient structural and functional analysis of these components. Due to the evolutionary conservation potential insights into the nuclear import mechanisms in yeast can be transferred to higher eukaryotes. Thus, yeast can be considered as a eukaryotic model system to study nuclear transport.
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    Heterologous protein production in yeast (1992)
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    Antonie van Leeuwenhoek 62 (1992), S. 79-93 
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    ISSN: 1572-9699
    Keywords: heterologous gene expression ; non-Saccharomyces yeast ; Saccharomyces cerevisiae ; secretion ; protein production
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The exploitation of recombinant DNA technology to engineer expression systems for heterologous proteins represented a major task within the field of biotechnology during the last decade. Yeasts attracted the attention of molecular biologists because of properties most favourable for their use as hosts in heterologous protein production. Yeasts follow the general eukaryotic posttranslational modification pattern of expressed polypeptides, exhibit the ability to secrete heterologous proteins and benefit from an established fermentation technology. Aside from the baker's yeastSaccharomyces cerevisiae, an increasing number of alternative non-Saccharomyces yeast species are used as expression systems in basic research and for an industrial application. In the following review a selection from the different yeast systems is described and compared.
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    Molecular biology of translation in yeast (1992)
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    Antonie van Leeuwenhoek 62 (1992), S. 47-62 
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    ISSN: 1572-9699
    Keywords: Saccharomyces cerevisiae ; genetics ; translation regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The combination of genetic, molecular and biochemical approaches have made the yeastSaccharomyces cerevisiae a convenient organism to study translation. The sequence similarity of translation factors from yeast and other organisms suggests a high degree of conservation in the translational machineries. This view is also strengthened by a functional analogy of some proteins implicated in translation. Beautiful genetic experiments have confirmed existing models and added new insights in the mechanism of translation. This review summarizes recent experiments using yeast as a model system for the analysis of this complex process.
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    The effects of dredging and fish stocking on the trophic status of shallow, peaty ditches (1992)
    Springer
    Hydrobiologia 233 (1992), S. 225-233 
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    ISSN: 1573-5117
    Keywords: ditches ; fish stock ; dredging ; biomanipulation ; eutrophication ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In the polder ‘Wormer, Jisp and Nek’, which forms part of a grossly eutrophicated region in the province North Holland, the effects of dredging and biomanipulation were studied in ditches. Four areas, including 5.7 ha surface water in total, were dammed up and dredged. It was feasible to remove the loose top-layer of sediments with a high content of phosphorus by modifications of the dredging machine. In two areas the fish stock was managed. The measures resulted in an improvement of the water quality: an increase of the transparency and a decrease of suspended solids, phosphorus, nitrogen and algae. The chlorophyll-a concentration decreased nearly to 100 µg l−1 (summer average). The relative densities of diatoms, green algae and cyanobacteria did not change. The zooplankton community was dominated by small rotifers and crustaceans both before and after restoration measures. Cladocerans were scarcely present. In the second year after the measures, submerged macrophytes developed.
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    Phytoplankton and zooplankton population dynamics and production of a recently formed African reservoir (1992)
    Springer
    Hydrobiologia 237 (1992), S. 47-60 
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    ISSN: 1573-5117
    Keywords: nitrogen ; phosphorus ; underwater light ; primary production ; secondary production
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The study provides a 2.5 year record of Rhenosterkop Dam (KwaNdebele, South Africa) plankton population dynamics and production in relation to physical and chemical changes which occurred during the trophic depression and stabilization phases of the reservoir. The mean volume of the reservoir was 4% of full storage capacity. Water temperatures ranged from 14 °C to 27 °C. Due to inorganic suspensoids, the euphotic zone averaged 2.6 m. An anaerobic zone developed each summer. The nitrogen, soluble reactive phosphorus (SRP) and silica concentrations did not displaya seasonal pattern, but the latter two nutrients declined over the study. The dominant phytoplankton group was the cryptophytes while the zooplankton population was dominated by crustaceans. Chlorophyll a concentrations ranged from 1.1 to 27 mg m−3 and were positively correlated to silica and SRP concentrations and inversely with NH4-N concentrations. Primary production ranged from 22.6 to 375 mgC m−2 h−1; changes in Amax were positively correlated to silica and SRP concentrations. Total zooplankton dry weight biomass varied from 〈0.5 to 〉4 mg l−1. Annual zooplankton (secondary) production was 8 to ∼ 15 gC m−3 a−1; both primary and secondary production were greatest in the first 12 months of study and remained at low levels for the remainder, similar to the trends for silica and SRP. The data indicate that the reservoir shifted from eutrophic to mesotrophic during the study, typical of events in new reservoirs, and that changes in the plankton populations were largely the result of changing nutrient concentrations.
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    Response of early and late semiarid seral species to nitrogen and phosphorus gradients (1992)
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    Plant and soil 140 (1992), S. 127-135 
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    ISSN: 1573-5036
    Keywords: nitrogen ; phosphorus ; root: shoot ratios ; secondary succession ; semiarid ; shrubland ; tissue nitrogen ; tissue phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Above- and below-ground biomass production, nitrogen (N) and phosphorus (P) tissue concentrations, and root: shoot ratios were examined for five species that are characteristic of a semiarid successional sequence under controlled greenhouse conditions. In two simultaneous experiments, seedlings of one forb, two grass, and two shrub species important in a sagebrush successional sere, were subjected to seven levels of N and P. Results of the experiments suggest distinct differences in nutrient response patterns between early and late seral species. Early seral species produced more biomass but had lower tissue nutrient concentrations than late seral species. As N and P availabilities decreased, late seral species displayed characteristics indicative of increasing competitive advantage over those of early seral species. Root: shoot ratios of the five species primarily reflected patterns related to lifeform, but with some early and late seral characteristics. Results from this study 1) confirm that nutrient use pattern, nutrient availability, and seral position relationships characteristic of mesic ecosystems hold equally true for semiarid systems, and 2) suggest that nutrients are important organizing factors in semiarid ecosystems.
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    Stoichiometric relationships among producers, consumers and nutrient cycling in pelagic ecosystems (1992)
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    Biogeochemistry 17 (1992), S. 49-67 
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    ISSN: 1573-515X
    Keywords: algae ; nitrogen ; nutrient ; phosphorus ; regeneration ; zooplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Most ecosystem models consolidate members of food-webs, e.g. species, into a small number of functional components. Each of these is then described by a single state variable such as biomass. When a multivariate approach incorporating multiple substances within components is substituted for this univariate one, a ‘stoichiometric’ model is formed. Here we show that the Nitrogen:Phosphorus ratio within zooplankton herbivores varies substantially intraspecifically but not intraspecifically. By using stoichiometric theory and recent measurements of the N:P ratio within different zooplankton taxa, we calculate large differences in ratios of nutrients recycled by different zooplankton species. Finally, we demonstrate that N:P stoichiometry can successfully account for shifts in N- and P-limitation previously observed in whole-lake experiments. Species stoichiometry merges food-web dynamics with biogeochemical cycles to yield new insights.
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    Nutrient and hydrologic budgets of a great lakes coastal freshwater wetland during a drought year (1992)
    Springer
    Wetlands ecology and management 1 (1992), S. 211-222 
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    ISSN: 1572-9834
    Keywords: freshwater marsh ; freshwater wetland ; Great Lakes ; hydrology ; phosphorus ; water quality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A coastal wetland along Lake Erie (Ohio, U.S.A.) was studied to determine hydrologic and phosphorus budgets and spatial and temporal variation of phosphorus and related chemical parameters. The wetland was influenced by changing Lake Erie water levels, seiches, shifting shoreline sediments, and watershed inflow during a year of severe drought. The water budget for a 7-month period (March – September, 1988) had average inflow of 15 200 m3 day−1 from the watershed and 3.5 m3 day−1 from Lake Erie. The wetland increased in volume by 700 m3 day−1 despite a drought that resulted in 80% more evapotranspiration than rainfall as a barrier beach isolated the wetland from Lake Erie for 77% of the study period. Conductivity decreased by 34% as water flowed through the wetland and turbidity and total suspended solids were variable and statistically similar at inflow and outflow. Average total phosphorus concentrations in the inflow and outflow were also similar (247 and 248 µg P l−1 respectively) although total soluble phosphorus and soluble reactive phosphorus decreased significantly (α=0.05) from inflow to outflow (averages 94 to 45 µg P l−1 and 7.5 to 4.0 µg P l−1 respectively). Nutrient budgets from field data estimate a retention of 36% of the phosphorus, presumably in the sediments (0.8 mg P m−2 day−1). A general nutrient retention model, an estimated deposition rate from a sediment core and a simulation model predicted higher mass retention of phosphorus but similar percentage retention. Sommaire Un marecage qui côtoie le lac Erie (USA) a servi de site expérimental pour en déterminer les budgets d'eau et de phosphore, de même que pour la variation spatiale et temporelle du phosphore et d'autres facteurs chimiques. Le marécage a été influencé par: niveaux d'eau qui changeaient; seiches; sédiments mouvants du littoral; et afflux de la ligne de partage des eaux dans une année de grande sécheresse. Le budget d'eau dans une période de 7 mois (mars–septembre 1988) montre un afflux de 15 200 m3 jour−1 de la ligne de partage, et 3.5 m3 jour−1 du lac Erie. Le volume du marécage a augmenté par 700 m3 jour−1 malgré une sécheresse qui a produit plus d'évapotranspiration (80%) que de pluie pendant qu'une plage-obstacle a isolé le marecage du lac Erie pendant 77% de la période d'observation. La conductivité a diminué par 34% pendant que l'eau coulait, et la turbidité et les TSS ont varié, tout en démontrant des statistiques similaires à l'afflux et au déversement. Les moyennes pour les concentrations du total du phosphore à l'afflux et au déversement ont été similaires (247 and 248 µg P l−1), quoique le TSP et le SRP ont diminué (α=0.05) de l'afflux au déversement (donant des moyennes de 94 à 45 µg P l−1 et de 7.5 à 4.0 µg P l'−1). Les budgets de substances nutritives pour les données suggèrent une reténtion de 36% du phosphore, évidemment dans les sédiments (0.8 mg P m−2 jour−1). Un modèle pour la rétention des nutrients, un taux de déposition, estimé par un noyau de sédiments, et une simulation avaient prédit un plus grand taux de rétention de phosphore, mais un pourcentage similaire pour la rétention.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00244926
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  • 99
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    Rhizome dynamics and resource storage in Phragmites australis (1992)
    Springer
    Wetlands ecology and management 1 (1992), S. 239-247 
    Details
    ISSN: 1572-9834
    Keywords: biomass ; carbohydrates ; nitrogen ; phosphorus ; Phragmites australis ; potassium ; reed ; rhizome ; translocation ; wetland
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Seasonal changes in rhizome concentrations of total nonstructural carbohydrates (TNC), water soluble carbohydrates (WSC), and mineral nutrients (N, P and K) were monitored in two Phragmites australis stands in southern Sweden. Rhizome biomass, rhizome length per unit ground area, and specific weight (weight/ length ratio) of the rhizomes were monitored in one of the stands. Rhizome biomass decreased during spring, increased during summer and decreased during winter. However, changes in spring and summer were small (〈 500 g DW m-2) compared to the mean rhizome biomass (approximately 3000 g DW m−2). Winter losses were larger, approximately 1000 g DW m-2, and to a substantial extent involved structural biomass, indicating rhizome mortality. Seasonal changes in rhizome length per unit ground area revealed a rhizome mortality of about 30% during the winter period, and also indicated that an intensive period of formation of new rhizomes occurred in June. Rhizome concentrations of TNC and WSC decreased during the spring, when carbohydrates were translocated to support shoot growth. However, rhizome standing stock of TNC remained large (〉 1000 g m−2). Concentrations and standing stocks of mineral nutrients decreased during spring/ early summer and increased during summer/ fall. Only N, however, showed a pattern consistent with a spring depletion caused by translocation to shoots. This pattern indicates sufficient root uptake of P and K to support spring growth, and supports other evidence that N is generally the limiting mineral nutrient for Phragmites. The biomass data, as well as increased rhizome specific weight and TNC concentrations, clearly suggests that “reloading” of rhizomes with energy reserves starts in June, not towards the end of the growing season as has been suggested previously. This resource allocation strategy of Phragmites has consequences for vegetation management. Our data indicate that carbohydrate reserves are much larger than needed to support spring growth. We propose that large stores are needed to ensure establishment of spring shoots when deep water or stochastic environmental events, such as high rhizome mortality in winter or loss of spring shoots due to late season frost, increase the demand for reserves.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00244929
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  • 100
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    Electronic Resource
    Bio-availability of iron from spinach (Spanicia oleracea) cultivated in soil fortified with graded levels of iron (1992)
    Springer
    Plant foods for human nutrition 42 (1992), S. 313-318 
    Details
    ISSN: 1573-9104
    Keywords: Iron availability ; phosphorus ; soil iron level ; ascorbic acid ; oxalic acid ; spinach
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In vitro availability of iron along with ascorbic acid, oxalic acid and phosphorus content of two varieties of spinach (Pusa Jyoti and Allgreen) cultivated in soil with different levels of added iron was determined. Addition of graded levels of iron to soil markedly increased the total iron and phosphorus contents and significantly decreased the bio-availability of iron, ascorbic acid and oxalic acid contents of spinach. Ascorbic acid and oxalic acid contents markedly exerted a positive influence while phosphorus exerted a negative influence on the bio-availability of iron.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02194092
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