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Showing papers by "National University of Singapore published in 1991"


Journal ArticleDOI
TL;DR: The finding that soya products may protect against breast cancer in younger women is of interest since these foods are rich in phyto-oestrogens.

794 citations


Journal ArticleDOI
01 Mar 1991
TL;DR: It is shown that, for excessive overshoot in the set-point response, set- point weighting can reduce the overshoot to specified values, and the original Ziegler-Nichols tuning formula can be retained, and it is also shown thatSet-point weighting is superior to the conventional solution of reducing large overshoot by gain detuning or set- Point filtering.
Abstract: The accuracy of the Ziegler-Nichols tuning formula is reviewed in the context of PID and PI autotuning. For PID autotuning, it is shown that, for excessive overshoot in the set-point response, set-point weighting can reduce the overshoot to specified values, and the original Ziegler-Nichols tuning formula can be retained. It is also shown that set-point weighting is superior to the conventional solution of reducing large overshoot by gain detuning or set-point filtering. However, for excessive set-point undershoot, the tuning formula will have to be modified. For PI autotuning, it is shown that the Ziegler-Nichols tuning formula is inadequate and has to be completely revised. The application of set-point weighting and the modification of the tuning formula can be based simply on the knowledge of the normalised gain or normalised deadtime of the process. These heuristic refinements, when incorporated, will give appreciable improvement in the performance of autotuners.< >

701 citations


Journal Article
TL;DR: Comparison of the average excesses by a method of repeated sampling with random permutations revealed no significant difference in effects among populations, indicating that a given apo E allele acts in a relatively uniform manner in different populations despite differences in genetic background and environmental factors.
Abstract: Application of uniform methods for measuring the apolipoprotein (apo) E polymorphism and plasma cholesterol levels in nine populations (Tyrolean, Sudanese, Indian, Chinese, Japanese, Hungarian, Icelandic, Finnish, and Malay) revealed significant heterogeneity among them in apo E type frequencies and mean cholesterol levels The major apo E types in all populations were E3/2 (frequency range from 70% in Indians to 169% in Malays), E3/3 (frequency range from 398% in Sudanese to 721% in Japanese), and E3/4 (frequency range from 113% in Japanese to 359% in Sudanese) Mean cholesterol levels ranged from 1442 mg/dl in the Sudanese to 2285 mg/dl in the Icelandics Two-way analysis of variance of the effect of population and apo E type on cholesterol levels showed no significantly interaction effect, indicating that the effects of apo E type on cholesterol levels do not differ significantly among the populations The overall average excess for the epsilon 2 allele was -1412 mg/dl (range -3163 to -882 mg/dl); for the epsilon 3 allele, 004 mg/dl (range -187 to 158 mg/dl; and for the epsilon 4 allele, 814 mg/dl (range -171 to 1331 mg/dl) Despite the apparent heterogeneity in these values, especially for the epsilon 4 allele, comparison of the average excesses by a method of repeated sampling with random permutations revealed no significant difference in effects among populations These data indicate that a given apo E allele acts in a relatively uniform manner in different populations despite differences in genetic background and environmental factors

525 citations


Posted Content
TL;DR: In this paper, it was shown that unless the permanent component is a random walk, the spectral density of increments in GNP at frequency zero does not identify the magnitude of permanent component.
Abstract: Much macroeconometric discussion has recently emphasized the economic significance of the size of the permanent component in GNP. Consequently, a large literature has developed that tries to estimate this magnitude measured, essentially, as the spectral density of increments in GNP at frequency zero. This paper shows that unless the permanent component is a random walk this attention has been misplaced: in general, that quantity does not identify the magnitude of the permanent component. Further, by developing bounds on reasonable measures of this magnitude, the paper shows that a random walk specification is biased towards establishing the permanent component as important.

243 citations


Journal ArticleDOI
TL;DR: A levonorgestrel-releasing IUD and the Copper T 380Ag IUD were in randomized comparison for seven years in five clinics, representing the most effective reversible contraceptive methods yet studied in long-term randomized trials.

227 citations


Journal ArticleDOI
TL;DR: In this article, thermal comfort field experiments were conducted in Singapore in both naturally ventilated high-rise residential buildings and air conditioned office buildings, and each of the 818 questionnaire responses was made simultaneously with a detailed set of indoor climatic measurements, and estimates of clothing insulation and metabolic rate.
Abstract: Thermal comfort field experiments were conducted in Singapore in both naturally ventilated highrise residential buildings and air conditioned office buildings. Each of the 818 questionnaire responses was made simultaneously with a detailed set of indoor climatic measurements, and estimates of clothing insulation and metabolic rate. Results for the air conditioned sample indicated that office buildings were overcooled, causing up to one-third of their occupants to experience cool thermal comfort sensations. These observations in air conditioned buildings were broadly consistent with the ISO, ASHRAE and Singapore indoor climatic standards. Indoor climates of the naturally ventilated apartments during the day and early evening were on average three degrees warmer than the ISO comfort standard prescriptions, but caused much less thermal discomfort than expected. Discrepancies between thermal comfort responses in apartment blocks and office buildings are discussed in terms of contemporary perceptual theory.

225 citations


Journal ArticleDOI
TL;DR: In this paper, a substructure approach is used to estimate the stiffness and damping coefficients of structures from measurement of dynamic responses, and the structures are decomposed into smaller subsystems for which state and observation equations are formulated and solved by the method of extended Kalman filter with a weighted global iteration algorithm.
Abstract: A substructure approach is used to estimate the stiffness and damping coefficients of structures from measurement of dynamic responses. The structures are decomposed into smaller subsystems for which state and observation equations are formulated and solved by the method of extended Kalman filter with a weighted global iteration algorithm. Substructural identification methods with and without overlapping members are proposed. In both methods, the convergence of the structural parameters to the optimal values is improved significantly with less computation time as compared to a complete structural approach. Numerical simulation studies are performed for three types of structures, namely a shear building, a plane frame building and a plane truss bridge. The effects of measurement noise and response observations required for identification of system parameters are also investigated.

204 citations


Journal ArticleDOI
TL;DR: The study indicates the protein-sparing capabilities of young red tilapia, a hybrid of Oreochromis mossambicus and O. niloticus, which increased with increasing dietary lipid content up to 18% and decreased thereafter.

197 citations


Journal ArticleDOI
TL;DR: In this article, the effects of option listing on the returns processes of the underlying securities are examined by looking at a sample of 200 firms which had options listed on them on the CBOE and the AMEX between 1973 and 1983.
Abstract: The effects of option listing on the returns processes of the underlying securities are examined in this paper by looking at a sample of 200 firms which had options listed on them on the CBOE and the AMEX between 1973 and 1983. We find that the listing of options leads to significantly lower variance in the daily returns or the underlying stocks. We also find that prices adjust much more quickly to new information and that the noise component declines after the listing of options. We trace the speedier price adjustment process to increased information collection after the listing and the reduced noise after the listing to a decline in the bid-ask spread after option listing, partially because of increased competition from market-makers on the option market and partially because of increased institutional interest in the stocks after listing.

194 citations


ReportDOI
TL;DR: Using a five-year panel of data for two hundred large U.S. manufacturing firms, this article found that having a subsidiary in a tax haven, Ireland, or one of the "four dragon" Asian countries - all characterized by low tax rates - is associated with lower U. S. tax ratios.
Abstract: It is often claimed that multinational firms avoid taxes by shifting income from high-tax to low-tax countries. Using a five year panel of data for two hundred large U.S. manufacturing firms, we find that U.S. tax liability, as a fraction either of U.S. sales or U.S. assets, is related to the location of foreign subsidiaries in a way that is consistent with tax-motivated income shifting. Having a subsidiary in a tax haven, Ireland, or one of the "four dragon" Asian countries - all characterized by low tax rates - is associated with lower U.S. tax ratios. Having a subsidiary in a high-tax region is associated with higher U.S. tax ratios. These results suggest that U.S. manufacturing companies shift income out of high-tax countries into the U.S., and from the U.S. to low-tax countries. Such behavior certainly lowers worldwide tax liabilities for larger U.S. manufacturing companies and appears to significantly lower their U.S. tax liabilities as well.

193 citations


Journal ArticleDOI
TL;DR: The concept of expanding triangles in English-knowing bilingualism is discussed in this article to enable some comprehension of an otherwise haphazard and infinite array of linguistic diversity involving the functions of English in Singapore.
Abstract: The concept ‘English-knowing bilingualism’ is particularly worthy of exploration in Singapore because of the rapidly evolving special nature of ‘bilingualism’ there and the penetration of English into several domains. The discourse of ‘English-knowing bilinguals’ in two main domains—at home and at school—is examined in terms of the range and depth of functional uses previously suggested. The discourse is explained with a new model, that of ‘expanding triangles’ involving an increasing English-speaking base population and two distinctive English speech clines in Singapore, graded on formality and proficiency considerations. The instrumental, regulative and interpersonal functions of language call for the subvariety of English found at the lower ends of the English speech clines in Singapore. The representative or informative and the heuristic functions have been served by the subvariety at the upper ends of the speech clines. The imaginative or innovative function has been traditionally served by a high variety of English but the lower varieties are also increasingly being used in codified texts such as poems, short stories and plays by Singaporean writers. The concept of expanding triangles in English-knowing bilingualism is detailed in this paper to enable some comprehension of an otherwise haphazard and infinite array of linguistic diversity involving the functions of English in Singapore.

Journal ArticleDOI
TL;DR: This article extends the treatment by considering the uptake of two metal species together, cadmium and zinc, under different experimental conditions and the results are discussed in terms of possible mechanistic interactions.
Abstract: Many microorganisms are capable of sequestering and concentrating heavy metals from their aqueous environment. While much research has beep carried out on the uptake of single species of metal ions, little attention seems to have been given to the study of multimetal ion systems. A mathematical model has previously been developed to describe the uptake of individual metal species by a microorganism. The model proposes two sequential processes: an initial rapid uptake due to cellular surface adsorption and a subsequent slow uptake due to membrane transport of the metal into the cells. This article extends the treatment by considering the uptake of two metal species together, cadmium and zinc, under different experimental conditions. The results are discussed in terms of possible mechanistic interactions.

Journal ArticleDOI
15 Nov 1991-Cell
TL;DR: Two Drosophila receptor-like tyrosine phosphatase genes, DPTP99A and DPTP10D, were characterized and protein products of these genes show distinct expression patterns specific to subsets of developing CNS axons.

Journal ArticleDOI
TL;DR: Analysis of signal transduction pathways of tumor necrosis factor and interleukin 1 in human fibroblasts indicates that IL-1 and TNF activate multiple protein kinases viz. a kinase(s) which activates microtubule-associated protein 2 (MAP-2) kinase, a kinases that phosphorylates the cap-binding protein, and a possibly novel serine/threonine protein kinase.

Journal ArticleDOI
TL;DR: This approach has several significant advantages over other conventional forecasting methods such as regression and Box-Jenkins; besides simplicity, another major advantage is that it does not require any assumption to be made about the underlying function or model to be used.

Journal ArticleDOI
TL;DR: It is proposed that the epithelial specificity of the HPV-16 enhancer is brought about via binding sites for supposed ubiquitous transcription factors, which apparently involves synergism between factors that vary in concentration and may include cell-specific functional differences residing outside the DNA-binding domain of these factors.
Abstract: The enhancer of human papillomavirus type 16 (HPV-16) is considered to be specific for epithelial cells, in particular for cervical carcinoma-derived cell lines. We reexamined this hypothesis with the complete enhancer as well as nonoverlapping subclones and found all clones to be active in epithelial cell lines derived from the epidermis and from carcinomas of the cervix, mammary gland, and colon, but inactive in fibroblast, lymphoma, and embryonal carcinoma cells. Although the virus infects only human mucosal epithelia, enhancer activity was independent of the exact type or of the species of origin of the transfected epithelial cell. In spite of epithelial cell specificity, we found that the activity of the HPV-16 enhancer varied strongly from a cytomegalovirus enhancer and the simian virus 40 enhancer in a cell line-dependent manner. This suggests varying quantitative contributions of enhancer elements rather than regulation by an all-or-none switch. Cell type specificity was maintained by a 91-bp subclone of the 400-bp enhancer. Most of the enhancer activity of this fragment was eliminated by alternative mutations in binding sites for the ubiquitous factors AP-1, nuclear factor 1 (NF1), or TEF-2. These three types of factors bind this 91-bp enhancer without cooperation, although activation appears to be synergistic. Outside the 91-bp fragment, a motif typical for papillomavirus enhancers, namely an octamerlike sequence flanked by an NF1-binding site, contributes to enhancer function, as the activity was strongly reduced upon its deletion. In HPV-16, this motif is bound by the oct-1 factor as well as by a probably novel factor, NFA, whereas a related motif of HPV-11 is recognized only by NFA. On examination, none of the five types of transcription factors involved in HPV enhancer activation was restricted to epithelial cells, but NF1, AP-1, and oct-1 were present in higher concentration in HeLa cells than in fibroblasts. Only NF1 showed some qualitative cell type-specific differences. We propose that the epithelial specificity of the HPV-16 enhancer is brought about via binding sites for supposed ubiquitous transcription factors. The mechanism of this activation apparently involves synergism between factors that vary in concentration and may include cell-specific functional differences residing outside the DNA-binding domain of these factors.

Journal ArticleDOI
TL;DR: Hearing-impaired students may have developed a more alert peripheral vision as a result of their auditory impairment and make greater use of visual communication and need to monitor new information more via the visual channel.
Abstract: Hearing and nonhearing students responded to stimuli presented in their central and peripheral visual fields. No significant difference was found between the reaction times of hearing and nonhearing students in the central visual field condition. However, in the peripheral visual field condition, nonhearing students were significantly faster than hearing students. Hearing-impaired students may have developed a more alert peripheral vision. Perhaps, as a result of their auditory impairment, nonhearing students make greater use of visual communication and need to monitor new information more via the visual channel. Specific suggestions for future research on the development of peripheral vision are discussed.

Journal ArticleDOI
TL;DR: Genomic variability between different viral isolates provides a powerful epidemiological tool for verifying ultrasensitive diagnostic procedures, understanding infectious pathways in individuals and human populations, and studying viral evolution, and suggests that the variants did not originate over a short period in the individual patient but, rather, evolved consecutively while spreading throughout humankind.
Abstract: Genomic variability between different viral isolates provides a powerful epidemiological tool for verifying ultrasensitive diagnostic procedures, understanding infectious pathways in individuals and human populations, and studying viral evolution. The potential of this approach has not yet been exploited for the diagnosis of human papillomaviruses (HPVs) like HPV type 16 (HPV-16), which are involved in genital cancer. Toward this end, we amplified by polymerase chain reaction, cloned, and sequenced a 364-bp noncoding segment of the HPV-16 genome from cell lines, cervical biopsy specimens, and cervical smears. The HPV-16 genomes in the cell lines SiHa and CaSki showed an identical point mutation, and in the SiHa cell line it had an additional 38-bp deletion. Only 4 of 22 cervical lesions biopsied from patients at several hospitals in Singapore contained HPV-16 DNA with the prototype sequence, while the DNAs of the other 18 cervical lesions differed by 1 to 10 mutations. This excludes contaminations with cloned HPV-16 DNA as the source of this DNA. To test whether this diversity was a geographic idiosyncrasy, we analyzed 25 cervical biopsy specimens from Brazil. Eight of these contained the prototype sequence, while 17 were mutated. Altogether, 11 genomic variants were found in the Singaporean samples and 12 genomic variants were found in the Brazilian samples, and only 5 of these occurred identically in both cohorts. All variants could be connected to form a phylogenetic tree, with some branches being specific for each cohort. This suggests that the variants did not originate over a short period in the individual patient but, rather, evolved consecutively while spreading throughout humankind.(ABSTRACT TRUNCATED AT 250 WORDS)

Journal ArticleDOI
TL;DR: The sequence of the SSII-1 toxin was compared with those of known toxins and was found to show regional homology to those of ADP-ribosyltransferase toxins.
Abstract: A cosmid library was prepared from a partial BamHI digest of total DNA from Bacillus sphaericus SSII-1. Two hundred fifty Escherichia coli clones were screened for toxicity against larvae of the mosquito Culex quinquefasciatus. One toxic clone, designated pKF2, was chosen for further study. Two toxic subclones, designated pXP33 and pXP34, obtained by ligating PstI-derived fragments of pKF2 into pUC18, contained the same 3.8-kb fragment, but in opposite orientations. Sequence analysis revealed the presence of an open reading frame corresponding to a 100-kDa protein and the 3' end of a further open reading frame having significant homology to open reading frames of transposons Tn501 and Tn21. The sequence of the SSII-1 toxin was compared with those of known toxins and was found to show regional homology to those of ADP-ribosyltransferase toxins. The distribution of the toxin gene among other B. sphaericus strains was examined.

Journal ArticleDOI
TL;DR: The author considers, exclusively, the case in which the fading process fluctuates from one symbol interval to the next, and exact bit error probability results for 2, 4, and 8 DPSK as well as tight upper bounds are derived.
Abstract: Data transmission using M-ary differential phase shift keying (MDPSK) over the nonselective Rayleigh fading channel with diversity reception is considered. While previous studies on error probability mostly assume no fading fluctuation, the author considers, exclusively, the case in which the fading process fluctuates from one symbol interval to the next. Exact bit error probability results for 2, 4, and 8 DPSK as well as tight upper bounds are derived. Some applications of the results are discussed. >

Journal ArticleDOI
TL;DR: This study explores the importance of pro-active client involvement when engaging a consultant to assist with computer system selection in small businesses and finds it to be integral to project success and frequently lacking due to mis-conceptions of small businesses regarding their role.

Journal ArticleDOI
TL;DR: Differences in substrate specificity and responses to effectors and the interdependence between the two domains are likely important properties in the function of this PTPase in signal transduction.
Abstract: Cloning and expression of the homologous domains of the receptor-like tyrosine phosphatase HPTP alpha shows that both domain 1 (D1) and domain 2 (D2) are enzymatically active. The two domains display different substrate specificities with D1 preferentially dephosphorylating MBP approximately RR-src greater than PNPP while D2 favours PNPP much much greater than RR-src and is inactive towards MBP. Each domain has lower activity than an expressed protein containing both domains. Analysis of chimaeric D1/2 proteins suggests that no particular region of D2 is responsible for the low activity of D2 on RR-src and that the specificity differences of D1 and D2 reflect overall sequence dissimilarities. Activities of D1 and D2 are inhibited by zinc, vanadate and EDTA and differentially susceptible to inhibition by heparin and poly(Glu4:Tyr1). Unusually, the activity of the protein containing both domains is stimulated by these polyanions. Regions amino-terminal to each domain are important for catalysis since deletion of these sequences abolishes phosphatase activity. Activity of the double domain polypeptide was also lost upon deletion of the sequence amino-terminal to D1, indicating that inactivation of D1 may suppress D2 activity. Differences in substrate specificity and responses to effectors and the interdependence between the two domains are likely important properties in the function of this PTPase in signal transduction.

Journal ArticleDOI
TL;DR: The establishment, maintenance, and behavior of human tubal cell lines is first presented, followed by their use as cocultures for fertilization and cleavage of embryos and the currently available results of pregnancies after coculture are presented.

Journal ArticleDOI
TL;DR: Seabass larvae fed all-protein-membrane microcapsules from first feeding, either alone or together with rotifers, had a mean survival rate of 2.4%.

Journal ArticleDOI
TL;DR: In this article, a diffusion model was used to study the drying characteristics of sliced tomato specimens and an equation was also developed to estimate the drying time to reach a particular moisture level.

Journal ArticleDOI
TL;DR: In this paper, the ternary systems polysulfone/solvent/water and polyethersulfon/solent/water were determined by a titration method.

Journal ArticleDOI
TL;DR: The promotive effect of AgNO(3) and aminoethoxyvinylglycine (AVG) on in vitro shoot regeneration from cotyledons of Brassica campestris ssp.
Abstract: The promotive effect of AgNO3 and aminoethoxyvinylglycine (AVG) on in vitro shoot regeneration from cotyledons of Brassica campestris ssp. pekinensis in relation to endogenous 1-amino-cyclopropane-1-carboxylic acid (ACC) synthase, ACC, and ethylene production was investigated. AgNO3 enhanced ACC synthase activity and ACC accumulation, which reached a maximum after 3 to 7 days of culture. ACC accumulation was concomitant with increased emanation of ethylene which peaked after 14 days. In contrast, AVG was inhibitory to endogenous ACC synthase activity and reduced ACC and ethylene production. The promotive effect of AVG on shoot regeneration was reversed by 2-chloroethylphosphonic acid at 50 micromolar or higher concentrations, whereas explants grown on AgNO3 medium were less affected by 2-chloroethylphosphonic acid. The distinctive effect of AgNO3 and AVG on endogenous ACC synthase, ACC, and ethylene production and its possible mechanisms are discussed.

Journal ArticleDOI
TL;DR: The high prevalence rate in this series is at variance with the widely held belief that diverticulosis occurs less frequently in oriental communities, and the distribution of the disease showed a predominance of right-sided disease.
Abstract: Five hundred twenty four consecutive barium enemas done over an 18-month period were reviewed in Singapore to ascertain the prevalence and distribution of diverticular disease in the large bowel. In this study, the prevalence rate was 20 percent, which is comparable to European and American studies but higher than similar studies in Asian countries. However, the distribution of the disease showed a predominance of right-sided disease (70 percent). This is a pattern that is markedly different from that seen in Europe and North America, where the disease involves largely the left side of the large bowel. The high prevalence rate in this series is at variance with the widely held belief that diverticulosis occurs less frequently in oriental communities.

Journal ArticleDOI
TL;DR: It is shown that a novel brain-specific cDNA, neuronal chimaerin (NC), expressed in Escherichia coli, binds phorbol ester with high affinity, stereospecificity and a phospholipid requirement, suggesting an involvement of this domain in protein-lipid interactions.
Abstract: Diacylglycerol (DG) and its analogue phorbol 12-myristate 13-acetate (PMA) activate the ubiquitous phospholipid/Ca2(+)-dependent protein kinase, protein kinase C (PKC), and cause it to become tightly associated with membranes. DG is produced transiently as it is rapidly metabolized by DG kinase (DGK) to phosphatidic acid. Phorbol esters such as PMA are not metabolized and induced a prolonged membrane association of PKC. Until recently, PKC was the only known phorbol ester receptor. We have shown that a novel brain-specific cDNA, neuronal chimaerin (NC), expressed in Escherichia coli, binds phorbol ester with high affinity, stereospecificity and a phospholipid requirement [Ahmed, Kozma, Monfries, Hall, Lim, Smith & Lim (1990) Biochem. J. 272, 767-773]. The proteins NC, PKC and DGK possess a cysteine-rich domain with the motif HX11/12CX2CXnCX2CX4HX2CX6/7C (where n varies between 12 and 14). The partial motif, CX2CX13CX2C, is present in a number of transcription factors including the steroid hormone receptors and the yeast protein, GAL4, in which zinc plays a structural role of co-ordinating cysteine residues and is essential for DNA binding (protein-nucleic acid interactions). The cysteine-rich domain of NC and PKC is required for phospholipid-dependent phorbol is required for phospholipid-dependent phorbol ester binding, suggesting an involvement of this domain in protein-lipid interactions. We have expressed recombinant NC, PKC and DGK glutathione S-transferase and TrpE fusion proteins in E. coli to investigate the relationship between the cysteine-rich motif, HX11/12CX2CX10-14CX2CX4HX2CX6/7C, zinc and phorbol ester binding. The cysteine-rich domain of NC, PKC and DGK bound 65Zn2+ but only NC and PKC bound [3H]phorbol 12,13-dibutyrate. When NC and PKC were subjected to treatments known to remove metal ions from GAL4 and the human glucocorticoid receptor, phorbol ester binding was inhibited. These data provide evidence for the role of a zinc-dependent structure in phorbol ester binding.

Journal ArticleDOI
TL;DR: Of all the Agrobacterium strains tested, A. tumefaciens A208-SE, carrying the disarmed Ti plasmid and a binary vector pROA93, was the most effective for B. juncea transformation.
Abstract: An efficient system for gene transfer into plants of Brassica juncea var. India Mustard, mediated by Agrobacterium tumefaciens. was developed through the manipulation of the culture medium and the use of the appropriate Agrobacterium strain. High frequency shoot regeneration (90–100%) was obtained from hypocotyl explants grown on medium containing 0.9% agarose, 3.3 mg/L AgNO3 and 0.5–2 mg/L BA in combination with 0.01–0.05 mg/L 2,4-D or 0.1–1 mg/L NAA. Of all the Agrobacterium strains tested, A. tumefaciens A208-SE, carrying the disarmed Ti plasmid and a binary vector pROA93, was the most effective for B. juncea transformation. pROA93 carries the coding sequences of the NPTII and the GUS genes, both driven by a common CaMV 35S promoter in two divergent directions. Inoculated explants grown on the selection medium in the presence of 0.5 mg/L BA and 0.1 mg/L NAA gave rise to transgenic shoots at the highest frequency (9%). All Ro transgenic plants were phenotypically normal, but variation in expression patterns of the GUS gene occurred among the transgenic plants in an organ- and tissue-specific manner. Both the NPTII and the GUS genes were transmitted to the R1 seed progeny and showed co-segregation.