Displaying publications 1 - 20 of 1561 in total

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  1. Identification of potential hot spots in the carboxy-terminal part of the Epstein-Barr virus (EBV) BNLF-1 gene in both malignant and benign EBV-associated diseases: high frequency of a 30-bp deletion in Malaysian and Danish peripheral T-cell lymphomas
    Sandvej K, Peh SC, Andresen BS, Pallesen G
    Blood, 1994 Dec 15;84(12):4053-60.
    PMID: 7994023
    In this study, we have sequenced the C-terminal part of the Epstein-Barr virus (EBV)-BNLF-1 gene encoding for the latent membrane protein-1 from tissues of EBV-positive Danish Hodgkin's disease (HD) and of Danish and Malaysian peripheral T-cell lymphomas (PTLs) and from tonsils of Danish infectious mononucleosis (IM). Our study showed that some of the 7 single-base mutations and the 30-bp deletion previously detected between codons of amino acid 322 and 366 in the BNLF-1 gene of the nasopharyngeal carcinoma cell line CAO were present in all Malaysian PTLs and in 60% of the Danish PTLs. In HD and the IM cases, the mutations were present in about 30%. The 30-bp deletion and the single base mutations occurred independently, and mutations were detectable in the majority of EBV type B-positive cases. These findings suggest that the 30-bp deletion and the 7 single-base mutations in the C-terminal part of the CAO-BNLF-1 gene do not characterize a new EBV type A substrain. Rather, some of the positions of single base mutations and the 30-bp deletion are hot spots that may have mutated independently through the evolution of EBV strains.
    Matched MeSH terms: Gene Expression Regulation, Viral
  2. Significantly increased activated T cells are associated with declining CD4 cells in human immunodeficiency virus positive patients
    Dhaliwal JS, Balasubramaniam T, Quek CK, Arumainnathan S, Nasuruddin BA
    Ann Acad Med Singap, 1995 Nov;24(6):785-8.
    PMID: 8838981
    A cross-sectional study on the expression of 6 lymphocyte markers was carried out on 481 patients with human immunodeficiency virus (HIV) and 79 normals after stratification based on absolute CD4 counts. The data were stratified according to the following groups: (I) 1201 to 1600, (II) 801 to 1200, (III) 401 to 800 and (IV) 0 to 400 (x 10(6) CD4 cells per mm3). The mean percentages of the subsets before stratification showed that HIV patients had increased percentages of CD3+ (75.7 against 66.9), CD3+CD8+ (52.2 against 32.3) and CD3+HLA-DR+ (36.1 against 14.4) cells and lower percentages of CD19 (10.3 against 13.3) and natural killer cells (13.7 against 20.4) when compared to controls in the same group. A definite trend, however, was only seen in CD3+CD8+ (47.4, 50.0, 54.0, 57.5 for groups I, II, III and IV respectively) and CD3+HLA-DR+ (29.1, 32.9, 38.4, 43.9 for groups I, II, III and IV respectively).
    Matched MeSH terms: Gene Expression Regulation
  3. Cloning and characterization of cDNAs encoding three isoforms of phospholipase A2 in Malayan spitting cobra (Naja naja sputatrix) venom
    Armugam A, Earnest L, Chung MC, Gopalakrishnakone P, Tan CH, Tan NH, et al.
    Toxicon, 1997 Jan;35(1):27-37.
    PMID: 9028006
    cDNAs encoding three phospholipase A2 (PLA2) isoforms in Naja naja sputatrix were cloned and characterized. One of them encoded an acidic PLA2 (APLA) while the others encoded neutral PLA2 (NPLA-1 and NPLA-2). The specific characteristics of APLA and NPLA were attributed to mutations at nt139 and nt328 from G to C and G to A, respectively, resulting in amino acid substitutions from Asp20 and 83 in APLA to His20 and Asn83 in NPLA. Amino acid sequencing of purified protein also showed the presence of this Asp20 and His20 in APLA and NPLA, respectively. The cDNA encoding one of the PLA2 (NAJPLA-2A), when expressed in Escherichia coli, yielded a protein that exhibited PLA2 activity.
    Matched MeSH terms: Gene Expression Regulation
  4. Evaluation of five promoters for use in transformation of oil palm (Elaeis guineensis Jacq.)
    Chowdhury MKU, Parveez GKA, Saleh NM
    Plant Cell Rep, 1997 Feb;16(5):277-281.
    PMID: 30727662 DOI: 10.1007/BF01088280
    The efficiency of GUS (β-Glucuronidase) gene expression in embryogenic callus and young leaflets of mature and seedling palm after microprojectile bombardment with five constructs (pEmuGN, pAHC25, pAct1-F4, pGH24 and pBARGUS) was evaluated to identify the most suitable promoter(s) to use in transformation attempts in oil palm. Expression of the GUS gene driven by theEmu, Ubi1, Act1 35S orAdh1 was assayed, both histochemically and fluorometrically, from a total of 200 plates of tissues in eight independent experiments two days after bombardment. A completely randomized experimental design was used for each experiment, and the data analysed by ANOVA and Duncan's Multiple Range Test. The expression level of GUS driven by theEmu orUbi1 promoters was significantly higher than that of the Act], 35S and Adhl promoters in many experiments, and that of theAdhl was significantly lower than those of the other four promoters. Both histochemical and fluorometric data indicate that in embryogenic callus, the expression of theEmu promoter was higher than that of theUbi1 whereas in young leaflets from mature palm the Ubi1 expression was stronger. The performances of the five promoters were also tested in tobacco callus using a fluorometric GUS assay. The activity of the 35S promoter was highest, and significantly different from that of all the other promoters except theEmu, and that of theAct1 promoter was lowest. These results indicate that either theUbil orEmu promoter should facilitate the expression of desired genes in oil palm and aid in development of an efficient stable transformation system.
    Matched MeSH terms: Gene Expression
  5. Detection of human herpesvirus 7 in salivary glands
    Yadav M, Nambiar S, Khoo SP, Yaacob HB
    Arch Oral Biol, 1997 Aug;42(8):559-67.
    PMID: 9347118
    The prevalence and cellular distribution of human herpesvirus 7 (HHV-7) in archival labial salivary glands was analysed for virus-specific DNA sequences by polymerase chain reaction (PCR) and in situ hybridization signals. In addition, the cellular expression of HHV-7-encoded protein was detected by immunohistochemical staining with a virus-specific monoclonal antibody. Eleven of 20 samples were positive for the HHV-7 DNA sequence by PCR. Eighteen of 20 tissues analysed by in situ hybridization showed signals in ductal, serous and mucous cells. Some nuclei of these cells and also the myoepithelial population were positive. In immunolocalization studies, all 20 salivary glands consistently showed HHV-7-expressed protein in the cytoplasm of ductal cuboidal and columnar cells. The protein was also found in the cytoplasm of mucous and serous acinar cells that were immunopositive for HHV-7. The observations are consistent with the suggestion that the labial salivary gland is a site for virus replication, potential persistence and a source of infective HHV-7 in saliva.
    Matched MeSH terms: Gene Expression Regulation, Viral
  6. Six isoforms of cardiotoxin in malayan spitting cobra (Naja naja sputatrix) venom: cloning and characterization of cDNAs
    Jeyaseelan K, Armugam A, Lachumanan R, Tan CH, Tan NH
    Biochim. Biophys. Acta, 1998 Apr 10;1380(2):209-22.
    PMID: 9565688
    Cardiotoxins are the most abundant toxin components of cobra venom. Although many cardiotoxins have been purified and characterized by amino acid sequencing and other pharmacological and biochemical studies, to date only five cardiotoxin cDNAs from Taiwan cobra (Naja naja atra), three cDNAs from Chinese cobra (Naja atra) and two more of uncertain origin (either Chinese or Taiwan cobra) have been reported. In this paper we show the existence of four isoforms of cardiotoxin by protein analysis and nine cDNA sequences encoding six isoforms of cardiotoxins (CTX 1-3, 4a, 4b and 5) from N. n. sputatrix by cDNA cloning. This forms the first report on the cloning and characterization of several cardiotoxin genes from a single species of a spitting cobra. The cDNAs encoding these isoforms, obtained by reverse transcription-polymerase chain reaction (RT-PCR), were subsequently expressed in Escherichia coli. The native and recombinant cardiotoxins were first characterized by Western blotting and N-terminal protein sequencing. These proteins were also found to have different levels of cytolytic activity on cultured baby hamster kidney cells. Four of the isoforms (CTX 1, 2, 4 and 5) are unique to N. n. sputatrix, with CTX 2 being the most abundant species constituting about 50% of the total cardiotoxins. The isoform CTX 3 (20% constitution) is highly homologous to the cardiotoxins of N. n. atra and N. n. naja, indicating that it may be universally present in all Naja naja subspecies. Our studies suggest that the most hydrophilic isoform (CTX 5) could have evolved first followed by the hydrophobic isoforms (CTX 1, 2, 3 and 4). We also speculate that Asiatic cobras could be the modern descendants of the African and Egyptian counterparts.
    Matched MeSH terms: Gene Expression/genetics
  7. Cloning and sequencing of three new putative toxin genes from Clostridium bifermentans CH18
    Barloy F, Lecadet MM, Delécluse A
    Gene, 1998 May 12;211(2):293-9.
    PMID: 9602158
    Three new open reading frames were found downstream from cbm71, a toxin gene from Clostridium bifermentans malaysia (Cbm) strain CH18. The first one (91bp downstream) called cbm72, is 1857bp long and encodes a 71727-Da protein (Cbm72) with a sequence similar to that of Bacillus thuringiensis delta-endotoxins. This protein shows no significant toxicity to mosquito larvae. The two others, cbm17.1 (462bp) and cbm17.2 (459bp), are copies of the same gene encoding Cbm P18 and P16 polypeptides and located 426bp and 1022bp downstream from cbm72, respectively. They encode 17189-Da and 17451-Da proteins with sequences 44.6% similar to that of Aspergillus fumigatus hemolysin; however, they were not hemolytic in the conditions tested.
    Matched MeSH terms: Gene Expression/genetics
  8. Expression of c-erbB3 protein in primary breast carcinomas
    Naidu R, Yadav M, Nair S, Kutty MK
    Br. J. Cancer, 1998 Nov;78(10):1385-90.
    PMID: 9823984
    Expression of c-erbB3 protein was investigated in 104 primary breast carcinomas comprising nine comedo ductal carcinoma in situ (DCIS), 91 invasive ductal carcinomas and four invasive lobular carcinomas using two monoclonal antibodies, RTJ1 and RTJ2. Of the 91 invasive ductal carcinomas, seven contained the comedo DCIS component adjacent to the invasive component. An immunohistochemical technique was used to evaluate the association between expression of c-erbB3 and clinical parameters and tumour markers such as epidermal growth factor receptor (EGFR), c-erbB2, cathepsin-D and p53 in archival formalin-fixed paraffin-embedded tumour tissues. Our results indicated that RTJ1 and RTJ2 gave identical staining patterns and concordant results. It was found that the overexpression of c-erbB3 protein was observed in 67% (6/9) of comedo DCIS, 52% (44/84) of invasive ductal carcinomas, 71% (5/7) of carcinomas containing both the in situ and invasive lesions and 25% (1/4) of invasive lobular carcinomas. A significant relationship (P < 0.05) was observed between strong immunoreactivity of c-erbB3 protein and histological grade, EGFR and cathepsin-D, but not with expression of c-erbB2, p53, oestrogen receptor status, lymph node metastases or age of patient. However, we noted that a high percentage of oestrogen receptor-negative tumours (59%), lymph node-positive tumours (63%) and c-erbB2 (63%) were strongly positive for c-erbB3 protein. We have also documented that a high percentage of EGFR (67%), c-erbB2 (67%), p53 (75%) and cathepsin-D-positive DCIS (60%) were strongly positive for c-erbB3. These observations suggest that overexpression of c-erbB3 protein could play an important role in tumour progression from non-invasive to invasive and, also, that it may have the potential to be used as a marker for poor prognosis of breast cancer.
    Matched MeSH terms: Gene Expression Regulation, Neoplastic*
  9. Cloning, expression, and characterization of recombinant Hev b 3, a Hevea brasiliensis protein associated with latex allergy in patients with spina bifida
    Wagner B, Krebitz M, Buck D, Niggemann B, Yeang HY, Han KH, et al.
    J Allergy Clin Immunol, 1999 Nov;104(5):1084-92.
    PMID: 10550757
    BACKGROUND: Two natural rubber latex proteins, Hev b 1 and Hev b 3, have been described in spina bifida (SB)-associated latex allergy.

    OBJECTIVE: The aim of this study was to clone and express Hev b 3 and to obtain the immunologic active and soluble recombinant allergen for diagnosis of SB-associated latex allergy.

    METHODS: A complementary DNA (cDNA) coding for Hev b 3 was amplified from RNA of fresh latex collected from Malaysian rubber trees (Hevea brasiliensis). PCR primers were designed according to sequences of internal peptide fragments of natural (n) Hev b 3. The 5'-end sequence was obtained by specific amplification of cDNA ends. The recombinant (r) Hev b 3 was produced in Escherichia coli as a 6xHis tagged protein. Immunoblotting and inhibition assays were performed to characterize the recombinant allergen.

    RESULTS: An Hev b 3 cDNA clone of 922 bp encoding a protein of 204 amino acid residues corresponding to a molecular weight of 22.3 kd was obtained. In immunoblots 29/35, latex-allergic patients with SB revealed IgE binding to rHev b 3, as did 4 of 15 of the latex-sensitized group. The presence of all IgE epitopes on rHev b 3 was shown by its ability to abolish all IgE binding to nHev b 3. Hev b 3 is related to Hev b 1 by a sequence identity of 47%. Cross-reactivity between these 2 latex allergens was illustrated by the large extent of inhibition of IgE binding to nHev b 1 by rHev b 3.

    CONCLUSION: rHev b 3 constitutes a suitable in vitro reagent for the diagnosis of latex allergy in patients with SB. The determination of the full sequence of Hev b 3 and the production of the recombinant allergen will allow the epitope mapping and improve diagnostic reagents for latex allergy.

    Matched MeSH terms: Gene Expression
  10. Effect of a carotene concentrate on the growth of human breast cancer cells and pS2 gene expression
    Nesaretnam K, Jin Lim E, Reimann K, Lai LC
    Toxicology, 2000 Oct 26;151(1-3):117-26.
    PMID: 11074306
    Breast cancer is the most common cancer in women worldwide. The growth of breast cancer cells is either hormone-dependent or hormone-independent. Both types are represented in vitro by the estrogen-receptor positive (ER+) MCF-7 and the estrogen-receptor negative (ER-) MDA-MB-231 cell lines, respectively. The pS2 gene is an estrogen-regulated gene and serves as a marker for the ER+ tumours. Carotenoids are pigments with anti-cancer properties besides having pro-vitamin A, antioxidant and free-radical quenching effects. This study was designed firstly, to compare the effect of palm oil carotene concentrate with retinoic acid on the growth of the ER+ MCF-7 and the ER- MDA-MB-231 cells; and secondly to evaluate the effect of the palm oil carotene concentrate on the regulation of pS2 mRNA. The growth experiments were performed with monolayer cells seeded in phenol red free RPMI 1640 culture media and subsequently treated with varying concentrations of either retinoic acid or palm oil carotenoids. The cell numbers were determined at the start of each experiment and then at successive time intervals. The results showed that the palm oil carotene concentrate caused dose-dependent inhibition of estradiol-stimulated growth of MCF-7 cells but did not affect the proliferation of MDA-MB-231 cells. Retinoic acid caused similar, albeit more potent effects, as significant inhibition was observed at lower concentrations than the palm oil carotenoids. In the pS2 gene expression experiment, cell monolayers were treated with the carotene concentrate (10(-6) M), either with or without supplemented estradiol (10(-8) M), and subsequently the RNA was extracted. Northern blotting was performed and the regulation of pS2 mRNA determined using a 32P-labelled pS2 cDNA probe. The results showed that the palm oil carotene concentrate did not affect the expression of pS2 mRNA and are therefore independent of the estrogen-regulated pathway.
    Matched MeSH terms: Gene Expression Regulation, Neoplastic/drug effects*; Gene Expression Regulation, Neoplastic/genetics
  11. Kernel-specific cDNA clones encoding three different isoforms of seed storage protein glutelin from oil palm Elaeis guineensis
    Cha TS, Habib Shah F
    Plant Sci, 2001 Apr;160(5):913-923.
    PMID: 11297788
    The mRNA differential display method was used to identify and isolate cDNAs corresponding to transcripts that accumulate during the period of lipid synthesis, 12-20 weeks after anthesis (WAA) in the kernel of Elaeis guineensis, var. Tenera. We successfully isolated two cDNA clones, KT7 (312 bp) and KT8 (266 bp). Interestingly, both clones show 79% nucleotide sequence identity to each other. This suggests that both clones encode the isoforms of the same protein. We screened the kernel (15 WAA) cDNA library and isolated the clone pKT7 (587 bp) using KT7 as probe, and isolated another isoform with KT8 probe, which designated as pKT9 (900 bp). Clone pKT9 has 93% nucleotide identity to KT8 and only 46% to pKT7 in their 3'-untranslated region. All three clones displayed significant amino acid sequence identity to seed storage protein glutelin from monocotyledon and globulin from dicotyledon plants. The coding sequence of KT8 (106 bp) shows 76 and 97% identity to pKT9 and pKT7, respectively. Therefore, we suggest that clones KT8 and pKT7 are members of the same subfamily (A), while pKT9 belongs to another subfamily (B) of glutelin multigene families. Southern analysis shows that there are at least four members for the subfamily B. Northern analysis shows that these three members of the glutelin family are co-ordinately expressed and developmentally regulated during the development of the kernel. The transcripts begin to accumulate at 12 WAA, increase in 15 WAA and show a significant reduction at 17 WAA.
    Matched MeSH terms: Gene Expression Profiling
  12. Fulltext The association of the HLA class II antigens with clinical and autoantibody expression in Malaysian Chinese patients with systemic lupus erythematosus
    Azizah MR, Ainoi SS, Kuak SH, Kong NCT, Normaznah Y, Rahim MN
    Asian Pac J Allergy Immunol, 2001 Jun;19(2):93-100.
    PMID: 11699726
    The frequency of the HLA class II antigens/alleles (HLA-DR, DQ and DP) were studied in 70 Malaysian Chinese patients with systemic lupus erythematosus (SLE) to examine the contribution of these genes to disease susceptibility, their clinical expression and Immunological responses. This was done using modified PCR-RFLP technique. These samples were then compared with 66 ethnically matched controls. We found a strong association of the DQA1*0102 (p corr = 0.032, rr = 3.39), DQB1*0501 (p corr = 0.003, rr = 4.55), *0601 (p corr = 0.006, rr = 4.22) and DPB1* 0901(p corr = 0.02, rr = 4.58) with SLE. Clinically, we found a strong association of DR2 and DQA1*0301 with renal involvement and DQA1*0102 with alopecia. Immunologically, statistical analysis (Chi-square test ) showed a strong association of DQA1*0102 with anti-Ro/La antibodies while DQA1*0301 was observed to be strongly associated with antibodies to ds DNA. DQA1*0102 was found more frequently in those with a later disease onset (30 years of age or above). From these data we suggest that the HLA class II genes play a role in conferring disease susceptibility and clinical and immunological expression.
    Study site: SLE clinics, Pusat Perubatan Universiti Kebangsaan Malaysia (PPUKM), Kuala Lumpur, Malaysia
    Matched MeSH terms: Gene Expression
  13. Cloning, expression and display of the PreS domain of hepatitis B virus on filamentous bacteriophage M13
    Kok WL, Yusoff K, Nathan S, Tan WS
    J. Biochem. Mol. Biol. Biophys., 2002 Feb;6(1):55-8.
    PMID: 12186783
    The PreS domain of hepatitis B virus (HBV) is believed to be involved in virion assembly and attachment to a hepatocyte receptor during infection. In order to study the functions of this region, we fused it to the g3p protein of bacteriophage M13 that allows the fusion protein to be displayed at the tip of the filament. The fusion protein was detected by the anti-E tag antibody on a Western blot. The polypeptide in a soluble form was produced by transfecting a non-suppressor E. coli host cell with the recombinant phagemid. The soluble protein was detected in cytoplasm, in the periplasmic space and also in the medium. The functional display of the PreS domain would provide an alternative means to study its interactions with the nuleocapsid and hepatocytes.
    Matched MeSH terms: Gene Expression
  14. Induction of a putative metallothionein gene in the blood cockle, Anadara granosa, exposed to cadmium
    Chan MK, Othman R, Zubir D, Salmijah S
    Comp Biochem Physiol C Toxicol Pharmacol, 2002 Feb;131(2):123-32.
    PMID: 11879780
    The relationship between a putative metallothionein gene (MT) and exposure to cadmium (Cd) in blood cockles (Anadara granosa) is reported. In a 96-h dose-response experiment, mortality of cockles was found to proportionately increase in the range of 0.2-5.0 mg/l Cd with a calculated LC(50) of 2.94 mg/l. Exposure to 0.25 mg/l Cd for 16 days caused significant increases (P<0.05) in Cd concentrations in whole tissues, gills and hepatopancreas, and the accumulation of Cd in these tissues increased with the duration of exposure. Two cDNA libraries constructed using the hepatopancreas from control and Cd-treated cockles gave titres of 5.62 x 10(5) and 1.94 x 10(5) pfu/microg vector, respectively. A putative MT gene, AnaMT, of 510 nucleotides in length, was isolated from the treated cDNA library using a heterologous probe MT20 from the blue mussel, Mytilus edulis. Northern analyses using AnaMT as a probe indicated low expression of the MT mRNA in control animals. In cockles treated with 0.25 mg/l Cd for 4 days, MT mRNA level increased to approximately 168%, but declined to 108% at day 8. After 12 and 16 days of Cd treatment, expression of the MT gene was 138% and 187%, respectively, compared to the controls. These observations suggest that induction of the MT gene by a sublethal dose of Cd is rapid, occurring within 4 days of treatment.
    Matched MeSH terms: Gene Expression Regulation
  15. Induced expression of melittin, an antimicrobial peptide, inhibits infection by Chlamydia trachomatis and Mycoplasma hominis in a HeLa cell line
    Lazarev VN, Parfenova TM, Gularyan SK, Misyurina OY, Akopian TA, Govorun VM
    Int J Antimicrob Agents, 2002 Feb;19(2):133-7.
    PMID: 11850166
    As the number of pathogenic microbial strains resistant to different antibiotics increases, amphipathic peptides with antimicrobial activity are promising agents for the therapy of infectious diseases. This work deals with the effect of an amphipathic antimicrobial peptide, melittin, expressed within recombinant plasmid vectors, on infection with urogenital pathogens Chlamydia trachomatis and Mycoplasma hominis in HeLa cell culture. Recombinant plasmid constructs with the melittin gene under the control of the tetracycline-responsive promoter of human cytomegalovirus were obtained. We showed inhibition of C. trachomatis and M. hominis infection after the introduction of recombinant plasmid vectors expressing the melittin gene into the infected cell culture.
    Matched MeSH terms: Gene Expression Regulation/drug effects
  16. Cloning and expression of the phosphoprotein gene of Newcastle disease virus in Escherichia coli
    Kho CL, Tan WS, Yusoff K
    J. Biochem. Mol. Biol. Biophys., 2002 Apr;6(2):117-21.
    PMID: 12186767
    The phosphoprotein (P) gene of a heat stable Newcastle disease virus (NDV) was cloned, sequenced and expressed in Escherichia coli. SDS-PAGE analysis of the recombinant P protein (395 amino acids) and a C-terminal extension derivative (424 amino acids), gave rise to two distinct protein bands with molecular masses of approximately 53-55 and 56-58 kDa, respectively, which are approximately 26-30% heavier than those calculated from the deduced amino acid sequences. The differences in molecular mass on SDS-PAGE are thought to be attributed to the acidic nature of the P protein (pI=6.27) and also the different degrees of phosphorylation in the prokaryotic cell. Amino acid sequence comparison of the P protein among the published NDV strains showed that they were highly conserved particularly at the putative phosphorylation sites.
    Matched MeSH terms: Gene Expression
  17. Molecular characterization and expression of a putative ATPase domain from Eimeria tenella
    Chong SP, Jangi MS, Wan KL
    J. Biochem. Mol. Biol. Biophys., 2002 Apr;6(2):123-8.
    PMID: 12186768
    VCP (Valosin-Containing Protein), a member of the AAA (ATPases Associated to a variety of cellular Activities) family of proteins, possesses a duplicated highly conserved ATPase domain. An expressed sequence tag (EST), representing a clone from the Eimeria tenella merozoite cDNA library, was found to have high similarity to VCP genes from other organisms. A complete sequence derived from the corresponding clone (designated eth060) shows amino acid identity of 42-62% with other members of the VCP subfamily. Sequence analysis identified a putative ATPase domain in the eth060 sequence. This domain was PCR-amplified using gene-specific primers and cloned into a pBAD/Thio-TOPO expression vector. Expression in Escherichia coli demonstrated that the putative ATPase domain, which consists of 414 amino acid residues, produced a fusion protein of approximately 60 kDa in size.
    Matched MeSH terms: Gene Expression
  18. Glyphosate-resistant goosegrass. Identification of a mutation in the target enzyme 5-enolpyruvylshikimate-3-phosphate synthase
    Baerson SR, Rodriguez DJ, Tran M, Feng Y, Biest NA, Dill GM
    Plant Physiol, 2002 Jul;129(3):1265-75.
    PMID: 12114580
    The spontaneous occurrence of resistance to the herbicide glyphosate in weed species has been an extremely infrequent event, despite over 20 years of extensive use. Recently, a glyphosate-resistant biotype of goosegrass (Eleusine indica) was identified in Malaysia exhibiting an LD(50) value approximately 2- to 4-fold greater than the sensitive biotype collected from the same region. A comparison of the inhibition of 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) activity by glyphosate in extracts prepared from the resistant (R) and sensitive (S) biotypes revealed an approximately 5-fold higher IC(50)(glyphosate) for the (R) biotype. Sequence comparisons of the predicted EPSPS mature protein coding regions from both biotypes revealed four single-nucleotide differences, two of which result in amino acid changes. One of these changes, a proline to serine substitution at position 106 in the (R) biotype, corresponds to a substitution previously identified in a glyphosate-insensitive EPSPS enzyme from Salmonella typhimurium. Kinetic data generated for the recombinant enzymes suggests that the second substitution identified in the (R) EPSPS does not contribute significantly to its reduced glyphosate sensitivity. Escherichia coli aroA- (EPSPS deficient) strains expressing the mature EPSPS enzyme from the (R) biotype exhibited an approximately 3-fold increase in glyphosate tolerance relative to strains expressing the mature EPSPS from the (S) biotype. These results provide the first evidence for an altered EPSPS enzyme as an underlying component of evolved glyphosate resistance in any plant species.
    Matched MeSH terms: Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Plant
  19. Use of control analysis to study the regulation of plant lipid biosynthesis
    Ramli US, Baker DS, Quant PA, Harwood JL
    Biochem Soc Trans, 2002 Nov;30(Pt 6):1043-6.
    PMID: 12440968
    Control analysis is a powerful method to quantify the regulation of metabolic pathways. We have applied it to lipid biosynthesis for the first time by using model tissue culture systems from the important oil crops, olive ( Olea europaea L.) and oil palm ( Elaeis guineensis Jacq.). By the use of top-down control analysis, fatty acid biosynthesis has been shown to exert more control than lipid assembly under different experimental conditions. However, both parts of the lipid biosynthetic pathway are important, so that attempts to alter oil yield by manipulating the activity of a single enzyme step are very unlikely to produce significant increases.
    Matched MeSH terms: Gene Expression Regulation, Plant*
  20. Comparative EST analyses provide insights into gene expression in two asexual developmental stages of Eimeria tenella
    Ng ST, Sanusi Jangi M, Shirley MW, Tomley FM, Wan KL
    Exp Parasitol, 2002 11 13;101(2-3):168-73.
    PMID: 12427472
    The protozoan parasite Eimeria tenella has a complex life cycle that includes two major asexual developmental stages, the merozoite and the sporozoite. The expressed sequence tag (EST) approach has been previously used to study gene expression of merozoites. We report here the generation and analysis of 556 ESTs from sporozoites. Comparative analyses of the two datasets reveal a number of transcripts that are preferentially expressed in a specific stage, including previously uncharacterised sequences. The data presented indicate the invaluable potential of the comparative EST analysis for providing information on gene expression patterns in the different developmental stages of E. tenella.
    Matched MeSH terms: Gene Expression Regulation, Developmental/genetics*
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