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TUNA FISH (T-30) – A new proficiency testing material for the determination of As and Hg in seafood (1997)

Gawlik, B. ; Druges, Martine ; Bianchi, Michele ; [et al.]

Springer

Fresenius' journal of analytical chemistry 358 (1997), S. 441-445

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ISSN: 1432-1130

Source: Springer Online Journal Archives 1860-2000

Topics: Chemistry and Pharmacology

Notes: Abstract The quality of the aquatic and marine environment can be monitored by the determination of pollutants in organisms living in this environment. Certified reference materials and well-organised proficiency tests are powerful means of ensuring a constant level of quality and verifying the correct application of standardised methods. The preparation of a tuna fish proficiency testing material for the evaluation of quality of As and Hg monitoring in seafood is described. Preparation and characterisation of the material as well as studies on its homogeneity and stability are described. Concentrations of 3.4 ± 0.2 mg/kg total arsenic and 2.91 ± 0.09 mg/kg total mercury have been determined as target values. Moreover indicative values for some trace elements (Cd, Cu, Ni, Pb, Sr) and some major constituents (Al, Br, C, Ca, Cl, Fe, H, K, Mg, N, Na, P, S, Si, Zn) have also been measured.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s002160050443

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Expression of zein in long term cultures of wildtype and opaque-2 maize endosperms (1989)

Manzocchi, Lucia A. ; Bianchi, Michele W. ; Viotti, Angelo

Springer

Plant cell reports 7 (1989), S. 639-643

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ISSN: 1432-203X

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract It has been reported that long term cell cultures from maize endosperms are not completely de-differentiated, maintaining some tissue-specific synthesis. We analyzed the expression of zein (the major storage protein of maize seeds) in cultures derived from wildtype and opaque-2 maize endosperms. In wildtype cultures, our data indicate a severe restriction in zein accumulation, resulting both from reduction of transcription and from post-transcriptional events. No detectable zein proteins and trace amounts of transcripts were found in opaque-2 cultures, which do not therefore exhibit a distinctive opaque-2 phenotype.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00272049

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DNA methylation and tissue-specific transcription of the storage protein genes of maize (1988)

Bianchi, Michele W. ; Viotti, Angelo

Springer

Plant molecular biology 11 (1988), S. 203-214

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ISSN: 1573-5028

Keywords: endosperm development ; DNA methylation ; storage protein genes ; tissue-specific transcription ; Zea mays

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract We investigated the methylation state of a set of storage protein genes of maize, coding for zeins and glutelins, in different somatic tissues and in developing endosperms. These genes, present as multigene families in the maize genome and organized in clusters on different chromosomes, are coordinately and specifically transcribed only in endosperm cells. Southern blot analysis of DNA digested with methylation-sensitive restriction enzymes shows a specific and extensive undermethylation of zein and glutelin sequences in the endosperm, while a common methylated pattern is detected in the different somatic tissues and in the embryo. However, a constant fraction of endosperm DNA (∼35%) is methylated at all zein sequences, which are found to be heavily modified in pollen DNA as well. Undermethylation is extended along a zein cluster and cannot be explained by reduced levels of 5-methylcytosine in endosperm DNA with respect to other tissues. The undermethylated state of storage protein genes is already established at an early stage of endosperm development, when transcripts levels for both genes are almost undetectable.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00015672

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Functional analysis of the regulatory region of a zein gene in transiently transformed protoplasts (1992)

Giovinazzo, Giovanna ; Manzocchi, Lucia A. ; Bianchi, Michele W. ; [et al.]

Springer

Plant molecular biology 19 (1992), S. 257-263

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ISSN: 1573-5028

Keywords: zein promoters ; DNA-binding protein ; protoplast transformation ; GUS transient expression

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract The transcription of zein genes in maize is tissue-specific and developmentally regulated. The 5′ regulatory region of many zein genes contains two promoters, P1 and P2, lying approximately 1000 bases apart. The promoter/enhancer activity of various fragments of the two promoter regions of the zein gene E19 have been analysed by means of transient expression experiments. The results indicate that the various regions differentially affect the expression of the GUS reporter gene activity in protoplasts from tobacco leaves, maize immature endosperms and in vitro endosperm cell cultures. In tobacco protoplasts only the proximal promoter region, P2, activates GUS expression, while in endosperm culture cells only the distant promoter, P1, gives significant activity. The P1 region, both in direct and opposite orientation, stimulates a low level of GUS expression in protoplasts from immature endosperms.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00027347

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Arabidopsis homologs of the shaggy and GSK-3 protein kinases: molecular cloning and functional expression in Escherichia coli (1994)

Bianchi, Michele W. ; Guivarc'h, Dominique ; Thomas, Martine ; [et al.]

Springer

Molecular genetics and genomics 242 (1994), S. 337-345

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ISSN: 1617-4623

Keywords: ASK ; zeste-white 3 ; MCK1 ; PCR ; Glutathione-S-transferase

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract The conservation in evolution of fundamental signal transduction modules offers a means of isolating genes likely to be involved in plant development. We have amplified by PCR Arabidopsis cDNA and genomic sequences related to the product of the shaggy/zeste-white 3 (sgg) segment polarity gene of Drosophila. This regulatory protein is functionally homologous to glycogen synthase kinase-3 in mammals (GSK-3), which regulates, among others, the DNA-binding activity of the c-jun/AP1 transcription factor. Analysis of PCR products led to the identification of five genes; for two of which, corresponding full-length cDNAs, ASK-α and γ (for Arabidopsis shaggy-related protein kinase), were characterized. The encoded proteins were 70% identical to GSK-3 and sgg over the protein kinase catalytic domain and, after production in Escherichia coli, autophosphorylated mainly on threonine and serine residues, but phosphotyrosine was also detected. ASK-α and ASK-γ also phosphorylated phosphatase inhibitor-2 and myelin basic protein, on threonine and serine, respectively. The high conservation of the protein kinases of GSK-3 family, and their action at the transcriptional level, suggest that the ASK proteins have important functions in higher plants.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00280424

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