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B Piechulla

Publications and source records attributed to B Piechulla.

At least 19 recordsLinked to original sources
PubMed2006

Localization of methyl benzoate synthesis and emission in Stephanotis floribunda and Nicotiana suaveolens flowers.

The emission of fragrances can qualitatively and quantitatively differ in different parts of flowers. A detailed analysis was initiated to localize the floral tissues and cells which contribute to scent synthesis in STEPHANOTIS FLORIBUNDA (Asclepiadaceae) and NICOTIANA SUAVEOLENS (Solanaceae). The emission of scent compounds in these species is primarily found in the lobes of the corollas and little/no emission can be attributed to other floral organs or tissues. The rim and centre of the petal lobes of S. FLORIBUNDA contribute equally to scent production since the amount of SAMT (salicylic acid carboxyl methyltransferase) and specific SAMT activity compensate each other in the rim region and centre region. IN SITU immunolocalizations with antibodies against the methyl benzoate and methyl salicylate-synthesizing enzyme indicate that the adaxial epidermis with few subepidermal cell layers of S. FLORIBUNDA is the site of SAMT accumulation. In N. SUAVEOLENS flowers, the petal rim emits twice as much methyl benzoate due to higher total protein concentrations in the rim versus the petal centre; and, both the adaxial and abaxial epidermis house the BSMT (salicylic acid/benzoic acid carboxyl methyltransferase).

Apocynaceae↗
PubMed2006

Effects of phytoestrogen extracts isolated from rye, green and yellow pea seeds on hormone production and proliferation of trophoblast tumor cells Jeg3.

BACKGROUND: Phytoestrogens are a diverse group of non-steroidal plant compounds. Because they have chemical structures similar to estrogens they are able to bind on estrogen receptors in humans. OBJECTIVES: In this study, we tested the effects of crude phytoestrogen extracts from rye (Secale cereale), green pea (Pisum sativum) and yellow pea seeds (Pisum sativum cv.) on cell proliferation and the production of progesterone in trophoblast tumor cells of the cell line Jeg3. METHODS: Isoflavone extracts from green and yellow pea seeds and lignan extracts from rye seeds were obtained, using different extraction methods. Isolated extracts were incubated in different concentrations with trophoblast tumor cells. Untreated cells were used as controls. At designated times, aliquots were removed and tested for estradiol and progesterone production. In addition, we tested the effects of the phytoestrogen extracts on cell proliferation. RESULTS: Cell proliferation is significantly inhibited by potential phytoestrogens isolated from rye, green and yellow pea seeds in trophoblast tumor cells of the cell line Jeg3. We found a correlation between the effects of proliferation and production of estradiol in isoflavone extracts from green and yellow pea seeds in Jeg3 cells. In addition, higher concentrations of isoflavones isolated from green pea seeds and lignans from rye showed also a inhibition of progesterone production whereas higher concentrations of rye lignans elevated estradiol production in Jeg3 cells. CONCLUSION: A useful indicator test system for potential phytoestrogens could be established. Based on the obtained results it is proposed that green and yellow pea seeds contain measurable concentrations of isoflavones and rye seeds contain lignans which can be isolated and used for special human diet programs.

Cell Line, Tumor↗
PubMed2001

Visual representation by atomic force microscopy (AFM) of tomato spotted wilt virus ribonucleoproteins.

Atomic force microscopy (AFM) allows the observation of biological material without fixation procedures. Here we present AFM images of ribonucleoproteins (nucleocapsids) derived from a plant infecting RNA virus (tomato spotted wilt virus, TSWV), which have been recorded in contact mode. The nucleocapsids, prepared from systemically infected leaves of tobacco, were spreaded on a glass surface and dried in air, and appeared as regularly formed rings, resembling the proposed pseudocircular and panhandle structure of encapsidated genomic RNA. Average values between 1300 and 2200 nm of nucleocapsid lengths could be related to dimensions estimated by electron microscopy, thereby validating a filamentous configuration of the TSWV ribonucleoproteins. However, to our knowledge regular, ring-like forms of ribonucleoproteins have not been obtained by electron microscopy, which rather showed an amorphous structure of the virus particles. Hence, the AFM approach provides a starting point for further detailed studies on TSWV ribonucleoprotein complexes.

Centrifugation, Density Gradient↗
PubMed1999

Circadian expression of the light-harvesting complex protein genes in plants.

Photosynthesis is one of the important processes that enable life on earth. To optimize photosynthesis reactions during a solar day, most of them are timed to be active during the light phase. This includes the components of the thylakoid membranes in chloroplasts. Prominent representatives are the proteins of the light-harvesting complex (LHC). The synthesis of both the Lhc mRNA and the LHC protein occurs during the day and is regulated by the circadian clock, exhibiting the following pattern: increasing levels after sunrise, reaching a maximum around noon, and decreasing levels in the afternoon. To elucidate the involved control elements and regulatory circuits, the following strategies were applied: (1) analysis of promoters of Lhc genes, (2) analysis of DNA binding proteins, and (3) screening and investigation of mutants. The most promising elements found so far that may be involved in mediating the circadian rhythmicity of Lhc mRNA oscillations are a myb-like transcription factor CCA1 (Wang et al. 1997) and the corresponding DNA binding sequence (Piechulla et al. 1998).

Circadian Rhythm↗
PubMed1998

Identification of tomato Lhc promoter regions necessary for circadian expression.

Expression of the light-harvesting complex protein genes (Lhc) is under the control of a circadian clock. To dissect the molecular regulatory components of the circadian clock a promoter deletion analysis of four tomato Lhc genes was performed in transgenic tobacco plants. The important 5'-upstream promoter regions are present at different positions relative to the transcription start site of Lhc b1*1, b1*2, Lhc a3 and Lhc a4. A short sequence of 47 nucleotides is necessary for conferring circadian Lhc mRNA oscillations. Sequence alignment of the specified promoter regions revealed a novel motif 'CAANNNNATC'. This motif is conserved in 5'-upstream regions of clock controlled Lhc genes and overlaps with a sequence relevant in phytochrome mediated gene expression.

Base Sequence↗
PubMed1995

Diurnal Lhc gene expression is present in many but not all species of the plant kingdom.

The diurnal and circadian expression of light-harvesting genes (Lhc) is well documented for many plant species of the 'Angiospermae' division. Here we present the diurnal mRNA levels of species of the Gymnospermae, Pteridophyta, Bryophyta and Phycophyta divisions. Except for four Coniferophytina species, diurnal Lhc mRNA accumulation is detected in fern, moss and algae, supporting the idea that the concept of 'ciracadian clock'-controlled gene expression is an ancient process. Possible reasons why plants need the 'circadian clock' control mechanism are discussed.

Biological Clocks↗
PubMed1993

Concerted circadian oscillations in transcript levels of nineteen Lha/b (cab) genes in Lycopersicon esculentum (tomato).

Steady-state mRNA levels of nineteen members of the Lha/b (cab) gene family of Lycopersicon esculentum, encoding nine different types of light-harvesting complex (LHC) polypeptides, were determined by primer extension analysis. Each Lha/b gene is expressed and individual mRNAs accumulate to distinct levels. The relative contribution of each Lha/b mRNA to the total Lha/b mRNA levels is very similar in different green organs (leaves, stems, fruits, sepals) and after light treatment of etiolated seedlings. Detailed analysis of Lha/b mRNA accumulation in leaves under light/dark conditions, continuous darkness and continuous light revealed diurnal and circadian oscillations of Lha/b mRNAs for all genes. Only minor instances of divergence from a general expression pattern are apparent. Together these results indicate a concerted expression of all genes, suggesting that similar or identical molecular mechanisms and signal transduction chain control the expression of all Lha/b genes.

Base Sequence↗
PubMed1992

Diurnal and Circadian Light-Harvesting Complex and Quinone B-Binding Protein Synthesis in Leaves of Tomato (Lycopersicon esculentum).

In leaves of tomato (Lycopersicon esculentum), the synthesis of a light-harvesting complex (LHC) polypeptide of photosystem II and the quinone B (Q(B))-binding protein varies at different time points during the day. In vivo labeling with [(35)S]methionine revealed diurnal oscillations of synthesis of these thylakoid membrane proteins. Both proteins are synthesized at elevated levels right after the transition from darkness to light, a maximum is reached around noon, and decreasing levels were measured during the afternoon and night. In addition, in constant darkness both proteins were also synthesized to varied extents at different diurnal time points. Together, these results indicate that the synthesis of a LHC II and the Q(B)-binding protein is under the control of the circadian clock. This circadian oscillation of LHC II protein synthesis correlates with the very well documented circadian Lhc a/b mRNA accumulation.

Journal Article↗
PubMed1991

Determination of steady-state mRNA levels of individual chlorophyll a/b binding protein genes of the tomato cab gene family.

The steady-state levels of mRNA produced by 14 genes encoding members of the tomato chlorophyll a/b binding protein family were quantified. All genes were found to be expressed in leaf tissue, but the mRNAs accumulated to significantly different levels. The transcripts of cab 1A, cab 1B, cab 3A and cab 3B, encoding the Type I LHC proteins of photosystem II, are abundant, while low levels were measured for mRNAs encoding the Type II LHC II and the LHC I proteins. Sequences from the 5' upstream regions (-400 to translational start) of some cab genes were determined in this study, and a total of 16 tomato cab gene promoters for which sequences are now available were analyzed. Significant sequence conservation was found for those genes which are tandemly linked on the chromosome. However, the level of sequence conservation is different for the different cab subfamilies, e.g. 85% similarity between cab 1A and cab 1D vs. 45% sequence similarity between cab 3A and cab 3C upstream sequences. Characteristic GATA repeats with a conserved spacing were found in 5' upstream sequences of cab 1A-D, cab 3A-C, cab 11 and cab 12. The consensus sequence CCTTATCAT, which is believed to mediate light responsiveness, was found at different locations in the upstream sequences of cab 6B, cab 7, cab 8, cab 9, cab 10A, cab 10B and cab 11. In 11 out of 15 genes the transcription initiation site was found to center on the triplet TCA.

Base Sequence↗
PubMed1990

Effect of dark phases and temperature on the chlorophyll a/b binding protein mRNA level oscillations in tomato seedlings.

External parameters (e.g. light/dark alterations and temperature) were tested for their ability to influence the expression pattern of the chlorophyll a/b binding protein (cab) genes and the small subunit of RuBPC/Oase (rbcS) genes. Particular interest was focused on the alterations of diurnal/circadian oscillation patterns of cab mRNA levels. Chlorophyll a/b binding protein and small subunit of RuBPC/Oase mRNA oscillations were observed in tomato seedlings grown without environmental perturbations (constant illumination and temperature), indicating that these genes are controlled by an endogenous rhythm. The rhythmic fluctuation patterns revealed a period of about 32 hours and a weekly expressed amplitude. A several-fold increase of the cab mRNA amplitude and a reduction of the period to about 24 hours (circadian) was monitored after exposure of the tomato seedlings to 3, 6 or 9 hours of darkness. The elevated amplitude disappeared at consecutive days if seedlings were not exposed to further dark phases. A circadian rhythm with clearly expressed cab mRNA amplitudes was also present after the plants had been transferred to darkness at various circadian times. However, under those circumstances the time points of maximum and minimum transcript levels were shifted by respective hours. Alteration of the growth temperature from 24 degrees C to 10 degrees C or 30 degrees C at constant illumination or in a light/dark cycle resulted in a reduction of the amplitudes or of the steady-state mRNA levels. Such extreme temperature changes do not induce or enhance the diurnal cab mRNA oscillations.

Darkness↗
PubMed1990

Effect of Temperature Alterations on the Diurnal Expression Pattern of the Chlorophyll a/b Binding Proteins in Tomato Seedlings.

In the leaves of plants that are grown in the natural environment, the accumulation of mRNAs encoding the chlorophyll a/b binding proteins (CAB) follow a circadian rhythm. It is generally accepted that the day/night (sunset, light/dark) or night/day (sunrise, dark/light) transitions play an important role in the synchronization of the rhythm and the determination of the accumulation amplitude. As the results of the experiments presented in this paper indicate, temperature alterations also support the setting and the arrangement of the rhythm. Apparently, simulating "day/night" temperature alternations influences the tomato (Lycopersicon esculentum) plants to express a typical circadian oscillation pattern of cab mRNAs. This rhythm was sustained in the plants after long-term exposure to an alternating temperature regime. In constant conditions, e.g. continuous illumination at either 18 degrees C or 24 degrees C or in continuous darkness at 24 degrees C, this diurnal fluctuation pattern with a period of about 24 hours remained present for at least 2 days.

Journal Article↗
PubMed1990

Analysis of the diurnal expression patterns of the tomato chlorophyll a/b binding protein genes. Influence of light and characterization of the gene family.

Steady-state mRNA levels of the chlorophyll a/b binding (cab) proteins oscillate substantially during a diurnal cycle in tomato leaves. This accumulation pattern is also observed in complete darkness, supporting the hypothesis that the expression of cab genes is at least partially regulated by an endogenous rhythm ("biological clock"). The amplitude of the cab mRNA accumulation is dependent on the duration of illumination and the circadian phase in which light was applied to the tomato plants. These results at the molecular level correlate well with the photoperiodic phenomenon. The characterization of the expression pattern of individual members of the cab gene family was attempted. Distinct primer extension products were detected using specific oligonucleotides homologous to the cab 1, cab 4, cab 5 and cab 8 genes. Based on this analysis the transcription start sites of these genes were determined to be between position -70 and -9 upstream of the ATG codon. During the diurnal cycle the cab 1 and cab 4 genes exhibit the same expression pattern; no transcripts detected at 3 and 6 a.m., maximum mRNA levels were measured at noon and decreasing levels in the afternoon.

Base Sequence↗
PubMed1988

Light-regulated protein and mRNA synthesis in root caps of maize.

Illumination of maize roots initiates changes in mRNA levels and in the activities of proteins within the root cap. Using Northern analysis we showed a 5-6 fold increase in the levels of three specific mRNAs and a 14-fold increase in plastid mRNA. This increase is rapid, occurring within 30 minutes of illumination. With prolonged periods of darkness following illumination, messages return to levels observed in dark, control caps. For two species of mRNA illumination results in a reduction in message levels. Light-stimulated increases in the levels of specific mRNAs are proportionally greater than are increases in the activities of corresponding proteins. We suggest that the light-stimulated increase in protein activity in root caps may be preceded by and occur as a consequence of enhanced levels of mRNA. Our work suggests that photomorphogenesis in roots could involve changes in the levels of a wide variety of mRNAs within the root cap.

Adenosine Triphosphatases↗
PubMed1987

Diurnal mRNA fluctuations of nuclear and plastid genes in developing tomato fruits.

Steady-state transcript levels of nuclear (rbcS, cab) and plastid (rbcL, psbA) encoded photosynthesis-specific genes were determined at noon and 05.00 h in different developmental stages of tomato fruits (7-35 days after anthesis). Small alterations are observed in mRNA levels for the small subunit (ssu) and large subunit (lsu) of RuBPC/Oase and the QB-binding protein of photosystem II at these two time-points, while significant steady-state transcript level fluctuations are detectable for the light harvesting complex protein. LHCP II transcripts accumulate during the day, and decline to low levels during the night. In contrast, the LHC II protein levels remain constant during the same period of development. A detailed analysis of transcript levels of the nuclear and plastid genes at 4-h intervals throughout a 38-h period demonstrates that LHCP II mRNA accumulation is highest at noon and lowest at 04.00 h. The transcripts of the ssu and lsu of RuBPC/Oase, photosystem I and II reaction center proteins, as well as the beta-subunit of the mitochondrial ATPase and the beta-subunit of tubulin, accumulate during the night and decrease to low levels in the afternoon. The transcript levels of the genes examined in this study fluctuate with certain periodicities. We suggest that gene expression in developing tomato fruits is at least partially controlled by diurnal rhythms, which are therefore also operational in other organs, besides leaves, of higher plants.

Cell Nucleus↗
PubMed1987

Changes in Photosynthetic Capacity and Photosynthetic Protein Pattern during Tomato Fruit Ripening.

Levels of polypeptides participating in the photosynthetic light and dark reactions have been measured during fruit ripening in tomato. Photosynthetic proteins were identified by Western blot analysis with heterologous antibodies. The concentrations of proteins of photosystem (PS) I (14 kilodaltons), of PSII (47-kilodalton reaction center protein, 32-kilodalton ;Q(B) binding' protein and light harvesting complex proteins), of the photosynthetic electron transport chain (ferredoxin-NADP-oxidoreductase and plastocyanin), and of the stroma (ribulose-1,5-bisphosphate carboxylase) decrease during the ripening process. The 32-kilodalton protein and plastocyanin were detectable in pericarp protein preparations of ripe tomato fruits. Absorbance difference spectrophotometry provided information on the relative concentrations of PSII and PSI reaction centers in leaf and green fruit tissue of tomato. These results indicate that green fruit pericarp of tomato is photosynthetically active. Photosynthetic activity decreases during chloroplast/chromoplast differentiation. This is consistent with changes that occur at the transcript level of photosynthesis-specific proteins during the differentiation process.

Journal Article↗
PubMed1986

Isolation and immunological characterization of the four non-identical subunits of the soluble NAD-linked hydrogenase from Alcaligenes eutrophus H16.

The soluble NAD-linked hydrogenase of Alcaligenes eutrophus H16 is a tetramer consisting of 4 non-identical subunits with molecular weights of 63,000, 56,000, 30,000 and 26,000. Conditions have been elaborated to separate and isolate each of these subunits as a single polypeptide by a preparative scale of polyacrylamide gel electrophoresis in the presence of sodium dodecylsulfate (SDS). Against each of the 4 subunits, polyclonal antibodies were produced. From the crude sera isolated from rabbits, the antibodies (IgG fractions) were purified by Protein A-Sepharose chromatography. By the double immunodiffusion method, comparison of the 4 types of subunits revealed that they are in fact different polypeptides. Subunit 1 (Mr = 63,000) and subunit 2 (Mr = 56,000) only reacted with their own specific antibodies and showed no cross-reaction whatsoever with the antibodies raised against the other subunits. The only immunological relationship among the different subunits was observed with subunit 3 (Mr = 30,000) and subunit 4 (Mr = 26,000); the type of cross-reaction indicated that they are partially identical. A. eutrophus H16 contains, in addition to the soluble hydrogenase, a membrane-bound hydrogenase which is a dimer composed of 2 subunits with Mr of 61,000 and 30,000. Whereas the 2 native enzymes did not show any immunological cross-reaction with the respective antibodies, it was demonstrated by double immunofluorescence labeling on nitrocellulose filters that the larger subunit of the membrane-bound hydrogenase cross-reacted significantly with the antibodies raised against subunit 2 of the soluble hydrogenase.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcaligenes↗