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1.
The gene MUS81 (Methyl methansulfonate, UV sensitive) was identified as clone 81 in a two-hybrid screen using the Saccharomyces cerevisiae Rad54 protein as a bait. It encodes a novel protein with a predicted molecular mass of 72,316 (632 amino acids) and contains
two helix-hairpin-helix motifs, which are found in many proteins involved in DNA metabolism in bacteria, yeast, and mammals.
Mus81p also shares homology with motifs found in the XPF endonuclease superfamily. Deletion of MUS81 caused a recessive methyl methansulfonate- and UV-sensitive phenotype. However, mus81Δ cells were not significantly more sensitive than wild-type to γ-radiation or double-strand breaks induced by HO endonuclease.
Double mutant analysis suggests that Rad54p and Mus81p act in one pathway for the repair of, or tolerance to, UV-induced DNA
damage. A complex containing Mus81p and Rad54p was identified in immunoprecipitation experiments. Deletion of MUS81 virtually eliminated sporulation in one strain background and reduced sporulation and spore viability in another. Potential
homologs of Mus81p have been identified in Schizosaccharomyces pombe, Caenorhabditis elegans and Arabidopsis thaliana. We hypothesize that Mus81p plays a role in the recognition and/or processing of certain types of DNA damage (caused by UV
and MMS) during repair or tolerance processes involving the recombinational repair pathway.
Received: 9 December 1999 / Accepted: 24 February 2000 相似文献
2.
Van Laere KM Hartemink R Beldman G Pitson S Dijkema C Schols HA Voragen AG 《Applied microbiology and biotechnology》1999,52(5):681-688
Bifidobacterium adolescentis, a gram-positive saccharolytic bacterium found in the human colon, can, alongside other bacteria, utilise stachyose in vitro
thanks to the production of an α-galactosidase. The enzyme was purified from the cell-free extract of Bi. adolescentis DSM 20083T. It was found to act with retention of configuration (α→α), releasing α-galactose from p-nitrophenyl galactoside. This hydrolysis probably operates with a double-displacement mechanism, and is consistent with the
observed glycosyltransferase activity. As α-galactosides are interesting substrates for bifidobacteria, we focused on the
production of new types of α-galactosides using the transgalactosylation activity of Bi. adolescentisα-galactosides. Starting from melibiose, raffinose and stachyose oligosaccharides could be formed. The transferase activity
was highest at pH 7 and 40 °C. Starting from 300 mM melibiose a maximum yield of 33% oligosaccharides was obtained. The oligosaccharides
formed from melibiose were purified by size-exclusion chromatography and their structure was elucidated by NMR spectroscopy
in combination with enzymatic degradation and sugar linkage analysis. The trisaccharide α-d-Galp-(1 → 6)-α-d-Galp-(1 → 6)-d-Glcp and tetrasaccharide α-d-Galp-(1 → 6)-α-d-Galp-(1 → 6)-α-d-Galp-(1 → 6)-d-Glcp were identified, and this indicates that the transgalactosylation to melibiose occurred selectively at the C-6 hydroxyl group
of the galactosyl residue. The trisaccaride α-d-Galp-(1 → 6)-α-d-Galp-(1 → 6)-d-Glcp formed could be utilised by various intestinal bacteria, including various bifidobacteria, and might be an interesting pre-
and synbiotic substrate.
Received: 15 March 1999 / Received revision: 8 June 1999 / Accepted: 11 June 1999 相似文献
3.
Ascidians have been used extensively as model animals for experimental embryology. We report here the results of a pilot
study with the aim of developing genetic methods for the ascidian Ciona savignyi. The chemical mutagen N-ethyl-N-nitrosourea (ENU) was used to induce point mutations. F1 animals, produced by using sperm
from ENU-treated animals to fertilize untreated eggs, were grown to reproductive age. Sperm and eggs collected from the hermaphrodite
F1 adults were used to generate self-fertilized F2 broods, which were then screened for recessive, zygotically acting mutations.
Animals carrying potential mutations were outcrossed to wild type to test for the heritability of the phenotypes. We report
on a number of mutants isolated using this method, including several with abnormalities in tail and notochord development.
Received: 15 March 1999 / Accepted: 6 May 1999 相似文献
4.
Large-scale production of CMP-NeuAc and sialylated oligosaccharides through bacterial coupling 总被引:8,自引:0,他引:8
A large-scale production system of cytidine 5′-monophospho-N-acetylneuraminic acid (CMP-NeuAc) and sialyloligosaccharides was established by a whole-cell reaction through the combination
of recombinant Escherichia coli strains and Corynebacterium ammoniagenes. For the production of CMP-NeuAc, two recombinant E. coli strains were generated that overexpressed the genes of CMP-NeuAc synthetase and CTP synthetase, respectively. C. ammoniagenes contributed to the formation of UTP from orotic acid. CMP-NeuAc was accumulated at 27 mM (17 g/l) after a 27-h reaction starting
with orotic acid and N-acetylneuraminic acid. When E. coli cells that overexpressed the α-(2 → 3)-sialyltransferase gene of Neisseria gonorrhoeae were put into the CMP-NeuAc production system, 3′-sialyllactose was accumulated at 52 mM (33 g/l) after an 11-h reaction
starting with orotic acid, N-acetylneuraminic acid, and lactose. Almost no oligosaccharide byproducts other than 3′-sialyllactose were observed after
the reaction. The production of 3′-sialyllactose at a 5-l jar fermenter scale was almost the same as that at a beaker scale,
which indicated the high potential of the 3′-sialyllactose production on an industrial scale.
Received: 9 July 1999 / Received revision: 17 September 1999 / Accepted: 10 October 1999 相似文献
5.
6.
Kim HS Yoon BD Choung DH Oh HM Katsuragi T Tani Y 《Applied microbiology and biotechnology》1999,52(5):713-721
One yeast strain, SY16, was selected as a potential producer of a biosurfactant, and identified as a Candida species. A biosurfactant produced from Candida sp. SY16 was purified and confirmed to be a glycolipid. This glycolipid-type biosurfactant lowered the surface tension of
water to 29 dyne/cm at critical micelle concentration of 10 mg/l (1.5 × 10−5 M), and the minimum interfacial tension was 0.1 dyne/cm against kerosene. Thin-layer and high-pressure liquid chromatography
studies demonstrated that the glycolipid contained mannosylerythritol as a hydrophilic moiety. The hydrophilic sugar moiety
of the biosurfactant was determined to be β-d-mannopyranosyl-(1 → 4)-O-meso-erythritol by nuclear magnetic resonance (NMR) and fast atom bombardment mass–spectroscopy analyses. The hydrophobic moiety,
fatty acids, of the biosurfactant was determined to be hexanoic, dodecanoic, tetradecanoic, and tetradecenoic acid by gas
chromatography–mass spectroscopy. The structure of the native biosurfactant was determined to be 6-O-acetyl-2,3- di-O-alkanoyl-β-d-mannopyranosyl-(1 → 4)-O-meso-erythritol by NMR analyses. We newly determined that an acetyl group was linked to the C-6 position of the d-mannose unit in the hydrophilic sugar moiety.
Received: 18 December 1999 / Received last revision: 2 June 1999 / Accepted: 4 June 1999 相似文献
7.
S. Nakamori S. Kobayashi T. Nishimura H. Takagi 《Applied microbiology and biotechnology》1999,52(2):179-185
We derived l-methionine-analogue-resistant mutants from Escherichia coli JM109 strain by mutagenesis with N-methyl-N′-nitro-N-nitrosoguanidine and selected the potent l-methionine-overproducing strains by microbioassay using lactic acid bacteria. One of the mutants, strain TN1, produced approximately
910 mg l-methionine/l following the addition of 0.1% yeast extract to fundamental medium containing glucose and ammonium sulfate.
The l-methionine biosynthetic enzymes, cystathionine γ-synthase and cystathionine β-lyase, of the l-methionine-overproducing mutants were little repressed by l-methionine. To analyse the mechanism of l-methionine overproduction in the mutant strains, the metJ gene coding for the E. colimet repressor, MetJ protein, was cloned and sequenced by the polymerase chain reaction. The same single-amino-acid subsitution
(wild-type Ser → Asn) at position 54 was observed in four independent l-methionine-producing mutants. When the wild-type metJ gene was then introduced into strain TN1 having the mutant metJ gene, the level of enzyme synthesis and the l-methionine productivity in the transformants were found to revert to those of the wild-type. It was therefore considered
that only one point mutation in the metJ gene occurred in the l-methionine-producing mutants. These results demonstrate the important role of residue 54 of the MetJ protein in l-methionine overproduction, probably because of the derepression of l-methionine biosynthetic enzymes.
Received: 6 January 1999 / Received last revision: 19 February 1999 / Accepted: 26 February 1999 相似文献
8.
To check the possibilities of the recently developed comet assay, to be used in mechanistic studies in Drosophila melanogaster, neuroblast cells of third instar larvae are used to analyse in vivo, the effect of two repair deficient mutations: mus201, deficient on nucleotide excision repair, and mus308, deficient in a mechanism of damage bypass, on the genotoxicity of methyl methanesulphonate (MMS), ethyl methanesulphonate (EMS) and N-ethyl-N-nitrosourea (ENU). The obtained results reveal: (1) MMS-induced breaks are most probably consequence of N-alkylation damage mediated abasic (AP) site breakage; (2) MMS and at least part of the EMS induced damage leading to DNA strand breaks are efficiently repaired by the nucleotide excision repair mechanism; (3) ENU and part of EMS induced damage need a functional Mus308 protein to be processed, otherwise they can lead to DNA strand breaks. In addition, the results of this work confirm the validity of neuroblast cells to conduct the comet assay, and the usefulness of this assay in in vivo mechanistic studies related to DNA repair in D. melanogaster. 相似文献
9.
Hirozumi K Nakajima H Machida M Yamaguchi M Takeo K Kitamoto K 《Molecular & general genetics : MGG》1999,262(4-5):758-767
We have isolated the arpA gene from Aspergillus oryzae as a homologue of the Neurospora crassa ro-4 gene. In N. crassa, mutations in the ro-4 gene, which encodes a major component of the dynactin complex Arp1, causes curling of hyphae and abnormalities in nuclear
distribution. The arpA gene contains two introns and encodes a polypeptide of 381 amino acids, with a 78% sequence identity to the N. crassa Arp1. Overexpression of the arpA gene causes a defect in nuclear migration into elongating hyphae of germlings in A. oryzae. We constructed arpA disruptant strains of A. oryzae. The arpA null mutants showed poor growth and hyper-branched mycelia, as well as a nuclear distribution defect. Scanning electron microscopy
revealed that the arpA null mutant has an aberrant conidiophore morphology with irregular phialides.
Received: 26 January 1999 / Accepted: 22 July 1999 相似文献
10.
We propose a simple experiment to study delocalization and extinction in inhomogeneous biological systems. The nonlinear
steady state for, say, a bacteria colony living on and near a patch of nutrient or favorable illumination (“oasis”) in the
presence of a drift term (“wind”) is computed. The bacteria, described by a simple generalization of the Fisher equation,
diffuse, divide A→A + A, die A→ 0, and annihilate A + A→ 0. At high wind velocities all bacteria are blown into an unfavorable region (“desert”), and the colony dies out. At low
velocity a steady state concentration survives near the oasis. In between these two regimes there is a critical velocity at
which bacteria first survive. If the “desert” supports a small nonzero population, this extinction transition is replaced
by a delocalization transition with increasing velocity. Predictions for the behavior as a function of wind velocity are made
for one and two dimensions.
Received: 3 August 1998 / Revised version: 17 July 1999 / Published online: 4 July 2000 相似文献
11.
Bretting H Messer M Bornaghi L Kröger L Mischnick P Thiem J 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2000,170(8):601-613
Adult snails synthesize in their albumen glands a polysaccharide which is composed exclusively of D- or D- and L-galactose
(Gal) residues which are interglycosidically linked by 1 → 3 and 1 → 6 bonds. It is the only carbohydrate source for embryos
and freshly hatched snails. Two galactosyltransferases are described in this study which are most likely involved in the biosynthesis
of this polysaccharide. One identified in Helix pomatia acts on oligosaccharides and could be used to synthesize a tetrasaccharide when the branched trisaccharide D-Gal-β-(1 → 3)-[D-Galβ-(1 → 6)]-D-Galβ-1 → OMe
was offered as acceptor. This enzyme, requiring Mg++- and Mn++-ions for activity, introduced a linear β-(1 → 6) linkage at the terminal non-reducing ends and was not detected in Biomphalaria glabrata. The other enzyme, which introduced β-(1 → 6) linkages at subterminal D-Gal residues, thus forming branching points in the
polysaccharide, was found in H. pomatia, Arianta arbustorum and B. glabrata with comparable activities. With the enzyme preparation of H. pomatia, up to four D-Gal residues were introduced into vicinal positions, forming single-membered side chains, if a hexasaccharide
with five linearly β-(1 → 3)-linked D-Gal residues was offered as a acceptor. The multiple-branched structure formed is typical
for snail galactans, making this enzyme a prime candidate for the branching enzyme in galactan synthesis. The enzyme activity
could be solubilized and purified by affinity chromatography. In SDS-polyacrylamide electrophoresis, the Helix- derived eluate displayed two bands (68, 37 kDa) and that of Biomphalaria five bands (68, 63, 17.5; 15; 13 kDa). The purified material showed only 8% of the total activity of the crude extracts,
but it could be shown that a phosphatase present in the crude extract can degrade UDP formed in the transfer reaction and
thus drive the reaction to completion.
Accepted: 23 August 2000 相似文献
12.
Genes controlling hydroxylations of phytosiderophores are located on different chromosomes in barley (Hordeum vulgare L.) 总被引:3,自引:0,他引:3
Jian Feng Ma Shin Taketa Yi-Chieh Chang Takashi Iwashita Hideaki Matsumoto Kazuyoshi Takeda Kyosuke Nomoto 《Planta》1999,207(4):590-596
Phytosiderophores, mugineic acids, have been demonstrated to be involved in Fe acquisition in gramineous plants. In this
study, chromosomal arm locations of genes encoding for biosynthesis of various phytosiderophores were identified in a cultivar
of barley (Hordeum vulgare L. cv. Betzes). Using wheat (Triticum aestivum L. cv. Chinese Spring)-barley (cv. Betzes) ditelosomic addition lines for 4HS and 4HL, a gene for hydroxylation of 2′-deoxymugineic
acid to mugineic acid was localized to the long arm of barley chromosome 4H. To locate the gene for hydroxylation of mugineic
acid to 3-epihydroxymugineic acid, hybrids between the 4H addition line and other wheat-barley addition lines were studied.
Only a hybrid between 4H and 7H addition lines produced 3-epihydroxymugineic acid. The gene was further localized to the long
arm of chromosome 7H by feeding mugineic acid to ditelosomic addition lines for 7HS and 7HL. A new phytosiderophore was discovered
in both 7H and 7HL addition lines, which was identified to be 3-epihydroxy-2′-deoxymugineic acid by detailed nuclear magnetic
resonance studies. These results revealed that in barley there are two pathways from 2′-deoxymugineic acid to 3-epihydroxymugineic
acid: 2′-deoxymugineic acid → mugineic acid → 3-epihydroxymugineic acid and 2′-deoxymugineic acid → 3-epihydroxy-2′-deoxymugineic
acid → 3-epihydroxymugineic acid. Barley genes encoding for the hydroxylations of phytosiderophores are located in different
chromosomes and each gene hydroxylates different C-positions: the long arm of chromosome 4H carries the gene for hydroxylating
the C-2′ position and the long arm of chromosome 7H carries the gene for hydroxylating the C-3 position of the azetidine ring.
Received: 10 August 1998 / Accepted: 30 September 1998 相似文献
13.
Cappello S Liu NX Musselli C Brezicka FT Livingston PO Ragupathi G 《Cancer immunology, immunotherapy : CII》1999,48(9):483-492
Fucosyl-GM1 (Fuc-GM1) [Fucα1 → 2Galβ1 → 3GalNAcβ1 → 4(NeuAcα2-3)Galβ1 → 4Glcβ1 → O-Cer] is a small-cell-lung-cancer (SCLC)-associated ganglioside initially defined by the murine monoclonal antibody F12. On
the basis of its known distribution, Fuc-GM1 is a potential target for active immunotherapy in SCLC patients. Fuc-GM1 has
been extracted and purified from bovine thyroid. The immunogenicity of Fuc-GM1 was tested in mice either alone, mixed with
carrier protein keyhole limpet hemocyanin (KLH) or covalently linked with KLH, plus immunological adjuvant QS-21. The Fuc-GM1-KLH
conjugate plus QS-21 adjuvant was found to be optimal. It induced consistent IgM and IgG enzyme-linked immunosorbent assay
(ELISA) titers against Fuc-GM1. These antibodies were strongly reactive with the strongly Fuc-GM1-positive rat hepatoma cell
line H4-II-E, and they were moderately reactive with the moderately positive human SCLC cell line H146 by flow cytometry and
complement-mediated lysis. Both ELISA and fluorescence-activated cell sorting (FACS) reactions were inhibited with Fuc-GM1or
H4-II-E but not with the structurally related ganglioside GM1 or Fuc-GM1-negative colon cancer cell line LS-C. On the basis
of these results, a vaccine comprising Fuc-GM1-KLH plus QS-21 is being prepared for testing in patients with SCLC.
Received: 25 March 1999 / Accepted: 5 August 1999 相似文献
14.
Kengo Sakaguchi Paul V. Harris Robert Kuyk Andrew Singson James B. Boyd 《Molecular & general genetics : MGG》1990,224(3):333-340
Summary The mus308 mutants of Drosophila have previously been demonstrated to be defective in an enzyme that is designated Nuclease 3 (Boyd et al. 1990b). In this study that enzyme is shown to be present in mitochondria of both wild-type flies and embryos. Since the mus308 mutants are hypersensitive to DNA crosslinking agents, Nuclease 3 is potentially required for resistance of the mitochondrial genome to such agents. In support of this hypothesis, electron microscopic studies of mus308 mutant flies that had been exposed to nitrogen mustard revealed an increased frequency of mitochondrial abnormalities. Further investigation of the defect at the enzymological level revealed that the mutants possess a new nuclease activity that is apparently a modified form of the wild-type protein. In the earlier study, enzyme extracts from mus308 mutants were found to lack an enzyme with a pl of approximately 6.2. More precisely defined assay conditions in this study revealed the appearance of a new nuclease activity with a higher pI in extracts from mutants. This observation, together with the finding that only the normal enzyme form is present in heterozygous individuals, supports the hypothesis that the mus308 locus is not the structural gene for the enzyme. Rather, the mus308 gene product is necessary for Nuclease 3 to assume the lower pI. Nuclease 3 has been partially purified and characterized from wild-type embryos. Its activity is stimulated by Mg++ and ATP. Optimum activity is found at a pH of 5.5 and a NaCl concentration of 50–100 mM. Nuclease 3 exhibits a temperature optimum of 42°C and is insensitive to N-ethylmaleimide. The enzyme is probably membrane-associated because it exhibits a strong tendency to aggregate and detergent is required for full solubilization. 相似文献
15.
The enzyme oxaloacetate hydrolase (EC 3.7.1.1), which is involved in oxalate formation, was purified from Aspergillus niger. The native enzyme has a molecular mass of 360–440 kDa, and the denatured enzyme has a molecular mass of 39 kDa, as determined
by gel electrophoresis. Enzyme activity is maximal at pH 7.0 and 45 °C. The fraction containing the enzyme activity contained
at least five proteins. The N-terminal amino acid sequences of four of these proteins were determined. The amino acid sequences
were aligned with EST sequences from A. niger, and an EST sequence that showed 100% identity to all four sequences was identified. Using this EST sequence the gene encoding
oxaloacetate hydrolase (oah) was cloned by inverse PCR. It consists of an ORF of 1227 bp with two introns of 92 and 112 bp, respectively. The gene encodes
a protein of 341 amino acids with a molecular mass of 37 kDa. Under the growth conditions tested, the highest oah expression was found for growth on acetate as carbon source. The gene was expressed only at pH values higher than 4.0.
Received: 9 May 1999 / Accepted: 30 November 1999 相似文献
16.
A non-reducing trisaccharide, α-D-mannopyranosyl-(1 → 4)-α-D-glucuronopyranosyl-(1 → 2)-myo-inositol (MGI) accumulated in the spent medium of cell-suspension cultures of `Paul's Scarlet' rose (Rosa sp.) predominantly during the period of rapid cell growth. This trisaccharide was also produced by cultures of sycamore (Acer pseudoplatanus L.) but not by those of the graminaceous monocots maize (Zea mays L.) and tall fescue grass (Festuca arundinacea Schreb.). When added to cultured Rosa cells, [14C]MGI was neither taken up by the cells nor bound to the cell surface and was not metabolised extracellularly. When D-[6-14C]glucuronic acid was fed to cultured Rosa cells, extracellular [14C]MGI started to appear only after a 5-h lag period, compared with a 0.5-h lag period for labelling of extracelluar polysaccharides.
Furthermore, [14C]MGI continued to accumulate in the medium for at least 20 h after the accumulation of 14C-polymers had ceased. These observations indicate that extracellular MGI was produced from a slowly turning-over pool of
a pre-formed intermediate. Structural considerations indicate that the intermediate could be a glucuronomannan or a phytoglycolipid
(glycophosphosphingolipid). No Rosa polysaccharides could be found that generated MGI in the presence of living Rosa cells. We therefore favour phytoglycolipids as the probable biosynthetic origin of MGI.
Received: 29 April 1999 / Accepted: 13 June 1999 相似文献
17.
The fission yeast gene cps1, which encodes the catalytic subunit of β-glucan synthase, was isolated in a screen for mutants that show an increase in ploidy at the restrictive temperature. cps1 mutants display defects in both polarity and septation at the permissive temperature, and become swollen and multinucleate
at the restrictive temperature. Analysis of the interaction of cps1 with other mutations suggests the existence of a septation checkpoint, which requires the activity of the protein kinase
wee1 for function.
Received: 14 February 1999 / Accepted: 11 May 1999 相似文献
18.
Denis Kiktev Svetlana Moskalenko Olga Murina Agnès Baudin-Baillieu Jean-Pierre Rousset Galina Zhouravleva 《Molecular genetics and genomics : MGG》2009,282(1):83-96
The mechanisms leading to non-lethality of nonsense mutations in essential genes are poorly understood. Here, we focus on
the factors influencing viability of yeast cells bearing premature termination codons (PTCs) in the essential gene SUP45 encoding translation termination factor eRF1. Using a dual reporter system we compared readthrough efficiency of the natural
termination codon of SUP45 gene, spontaneous sup45-n (nonsense) mutations, nonsense mutations obtained by site-directed mutagenesis (76Q → TAA, 242R → TGA, 317L → TAG). The nonsense
mutations in SUP45 gene were shown to be situated in moderate contexts for readthrough efficiency. We showed that readthrough efficiency of
some of the mutations present in the sup45 mutants is not correlated with full-length Sup45 protein amount. This resulted from modification of both sup45 mRNA stability which varies 3-fold among sup45-n mutants and degradation rate of mutant Sup45 proteins. Our results demonstrate that some substitutions in the place of PTCs
decrease Sup45 stability. The viability of sup45 nonsense mutants is therefore supported by diverse mechanisms that control the final amount of functional Sup45 in cells. 相似文献
19.
The Aspergillus niger strain BO-1 was grown in batch, continuous (chemostat) and fed-batch cultivations in order to study the production of the
extracellular enzyme glucoamylase under different growth conditions. In the pH range 2.5–6.0, the specific glucoamylase productivity
and the specific growth rate of the fungus were independent of pH when grown in batch cultivations. The specific glucoamylase
producivity increased linearly with the specific growth rate in the range 0–0.1 h−1 and was constant in the range 0.1–0.2 h−1. Maltose and maltodextrin were non-inducing carbon sources compared to glucose, and the maximum specific growth rate was
0.19 ± 0.02 h−1 irrespective of whether glucose or maltose was the carbon source. In fed-batch cultivations, glucoamylase titres of up to
6.5 g l−1 were obtained even though the strain contained only one copy of the glaA gene.
Received: 5 May 1999 / Received revision: 7 September 1999 / Accepted: 17 September 1999 相似文献
20.
Transient expression and stable transformation of soybean using the jellyfish green fluorescent protein 总被引:13,自引:6,他引:7
Embryogenic soybean [Glycine max (L.) Merrill.] suspension cultures were bombarded with five different gene constructions encoding the jellyfish (Aequorea victoria) green fluorescent protein (GFP). These constructions had altered codon usage compared to the native GFP gene and mutations
that increased the solubility of the protein and/or altered the native chromophore. All of the constructions produced green
fluorescence in soybean cultures upon blue light excitation, although a soluble modified red-shifted GFP (smRS-GFP) was the
easiest to detect based on the brightness and number of foci produced. Expression of smRS-GFP was visible as early as 1.5 h
after bombardment, with peak expression at approximately 6.5 h. Large numbers of smRS-GFP-expressing areas were visible for
48 h postbombardment and declined rapidly thereafter. Stably transformed cultures and plants exhibited variation in the intensity
and location of GFP expression. PCR and Southern hybridization analyses confirmed the presence of introduced GFP genes in
stably transformed cultures.
Received: 23 September 1998 / Revision received: 4 January 1999 / Accepted: 15 January 1999 相似文献