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Parental Lines (parental + line)
Kinds of Parental Lines Selected AbstractsTumour cell,dendritic cell fusion for cancer immunotherapy: comparison of therapeutic efficiency of polyethylen-glycol versus electro-fusion protocolsEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 3 2002M. Lindner Abstract Background ,Fusion of tumour cells with dendritic cells (DC) is a powerful new technology to increase tumour vaccine immunogenicity. The aim of this study was to compare fusion protocols with syngenic DCs with respect to the efficiency of polyethylen-glycol-(PEG) and electric pulse-mediated fusions for induction of protective anti-tumour immune responses. As a model we chose a low immunogenic and metastatic murine mammary carcinoma cell line, which mimics clinically relevant tumour features. Methods FACS-staining, chromium release assay, therapeutic immunization, adoptive transfer. Results ,We show that the parental line with low cell surface expression of MHC molecules as well as a lacZ transfectant becomes highly immunogenic upon fusion with DCs. This was true for PEG- as well as for electro-fused cells. Immunization with products of DCs and tumour cells cocultivated for 16 h without the fusing agent PEG also caused induction of profound anti-tumour immunity, while this was not the case when using parental tumour cells or their lacZ transfectants as vaccines. Immune protection against the parental tumour cells after vaccination with fused cells was long-lasting and could be transferred via immune spleen cells into immuno-incompetent nude (nu/nu) mice. Conclusion ,Fusion products of DA3hi mammary carcinoma cells and DCs produced by an electric pulse were similar to those produced by PEG fusion with regard to vaccine potency in prophylactic antitumour immunization assays in vivo. Therefore, both techniques seem to be promising for clinical application. [source] Fungal endophytes in potato roots studied by traditional isolation and cultivation-independent DNA-based methodsFEMS MICROBIOLOGY ECOLOGY, Issue 3 2006Monika Götz Abstract The composition and relative abundance of endophytic fungi in roots of field-grown transgenic T4-lysozyme producing potatoes and the parental line were assessed by classical isolation from root segments and cultivation-independent techniques to test the hypothesis that endophytic fungi are affected by T4-lysozyme. Fungi were isolated from the majority of root segments of both lines and at least 63 morphological groups were obtained with Verticillium dahliae, Cylindrocarpon destructans, Colletotrichum coccodes and Plectosporium tabacinum as the most frequently isolated species. Dominant bands in the fungal fingerprints obtained by denaturing gradient gel electrophoresis analysis of 18S rRNA gene fragments amplified from total community DNA corresponded to the electrophoretic mobility of the 18S rRNA gene fragments of the three most abundant fungal isolates, V. dahliae, C. destructans and Col. coccodes, but not to P. tabacinum. The assignment of the bands to these isolates was confirmed for V. dahliae and Col. coccodes by sequencing of clones. Verticillium dahliae was the most abundant endophytic fungus in the roots of healthy potato plants. Differences in the relative abundance of endophytic fungi colonizing the roots of T4-lysozyme producing potatoes and the parental line could be detected by both methods. [source] Alpha-6 integrin is necessary for the tumourigenicity of a stem cell-like subpopulation within the MCF7 breast cancer cell lineINTERNATIONAL JOURNAL OF CANCER, Issue 2 2008Massimiliano Cariati Abstract The identification of mammary epithelial stem cells raises the hypothesis that these cells may be crucial in the pathogenesis of breast cancer. To further support this, a highly tumourigenic sub-population of cancer cells has recently been identified in primary and metastatic breast cancer samples. In this study, a sub-population of cells displaying features normally attributed to stem cells was identified within the breast cancer cell line MCF-7. This sub-population is capable of growth in anchorage-independent conditions as spherical organoids, displays resistance to proapoptotic agents and significantly greater tumourigenicity than its parental line, with as few as 1,000 cells able to form tumours in immunodeficient mice. Cells within this sub-population can be enriched by serial passages in anchorage-independence, and are characterized by over-expression of the adhesion molecule ,6-integrin. Alpha-6 integrin proves to be required for the growth and survival of these cells, as the knockdown of ITGA6 causes mammosphere-derived cells to lose their ability to grow as mammospheres and abrogates their tumourigenicity in mice. These findings support the existence of a highly tumourigenic sub-population in breast cancer cells. Furthermore, it shows ,6-integrin as a potential therapeutic target aimed at tumour-generating subsets of breast cancer cells. © 2007 Wiley-Liss, Inc. [source] Altered conjugate formation and altered apoptosis of multidrug-resistant human leukemia cell line affects susceptibility to killing by activated natural killer (NK) cellsINTERNATIONAL JOURNAL OF CANCER, Issue 1 2004Robin S. Treichel Abstract Most leukemias that exhibit P-glycoprotein (P-gp)-associated multidrug resistance (MDR) exhibit reduced susceptibility to immune cytotoxicity mediated by natural killer (NK) cells. To explore this phenomenon we investigated N6/ADR, a doxorubicin-selected, P-gp-positive variant of the human acute lymphoblastic leukemia (ALL) cell line NALM6. Each stage of the NK cytolytic pathway, (binding, activation and killing) was evaluated to identify the alterations responsible for the reduced cytotoxicity of the variant relative to its drug-sensitive parental line. The major cause of the decreased susceptibility to NK cytolysis was found to be reduced conjugate formation by the MDR variant. Activation of NK effectors by parental and MDR cells with concomitant release of tumor necrosis factor-alpha (TNF-,) correlated with conjugate formation. N6/ADR was also more resistant than NALM6 to antibody-dependent cellular cytotoxicity and to cytotoxic factors released from NK cells as measured both by 51Cr-release and by DNA fragmentation. This is the first report of a P-gp-positive leukemic line that exhibits reduced conjugate formation as well as increased resistance to NK-mediated killing mechanisms. Our results suggest caution in the use of NK-based immunotherapy as an alternative treatment for multidrug-resistant leukemias. © 2003 Wiley-Liss, Inc. [source] Paxillin modulates squamous cancer cell adhesion and is important in pressure-augmented adhesionJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 6 2006William C. Conway Abstract Paxillin is an adapter protein regulating signaling and focal adhesion assembly that has been linked to malignant potential in many malignancies. Overexpression of paxillin has been noted in aggressive tumors. Integrin-mediated binding through the focal adhesion complex is important in metastatic adhesion and is upregulated by extracellular pressure in malignant colonocytes through FAK and Src activation. Neither head and neck cancers nor paxillin have been studied in this regard. We hypothesized that paxillin would play a role in modulating squamous cancer adhesion both at baseline and under conditions of increased extracellular pressure. Using SCC25 tongue squamous cancer cells stably transfected with either an empty selection vector or paxillin expression and selection vectors, we studied adhesion to collagen, paxillin, FAK, and Src expression and phosphorylation in cells maintained for 30 min under ambient or 15 mmHg increased pressure conditions. Paxillin-overexpressing cells exhibited adhesion 121,±,2.9% of that observed in vector-only cells (n,=,6, P,<,0.001) under ambient pressure. Paxillin-overexpression reduced FAK phosphorylation. Pressure stimulated adhesion to 118,±,2.3% (n,=,6, P,<,0.001) of baseline in vector-only cells, similar to its effect in the parental line, and induced paxillin, FAK, and Src phosphorylation. However, increased pressure did not stimulate adhesion or phosphorylate paxillin, FAK, or Src further in paxillin-overexpressing cells. Metastasizing squamous cancer cell adhesiveness may be increased by paxillin-overexpression or by paxillin activation by extracellular pressure during surgical manipulation or growth within a constraining compartment. Targeting paxillin in patients with malignancy and minimal tumor manipulation during surgical resection may be important therapeutic adjuncts. J. Cell. Biochem. © 2006 Wiley-Liss, Inc. [source] Evaluation of stress- and immune-response biomarkers in Atlantic salmon, Salmo salar L., fed different levels of genetically modified maize (Bt maize), compared with its near-isogenic parental line and a commercial suprex maizeJOURNAL OF FISH DISEASES, Issue 4 2007A Sagstad Abstract The present study was designed to evaluate if genetically modified (GM) maize (Bt maize, event MON810) compared with the near-isogenic non-modified (nGM) maize variety, added as a starch source at low or high inclusions, affected fish health of post-smolt Atlantic salmon, Salmo salar L. To evaluate the health impact, selected stress- and immune-response biomarkers were quantified at the gene transcript (mRNA) level, and some also at the protein level. The diets with low or high inclusions of GM maize, and its near-isogenic nGM parental line, were compared to a control diet containing GM-free suprex maize (reference diet) as the only starch source. Total superoxide dismutase (SOD) activity in liver and distal intestine was significantly higher in fish fed GM maize compared with fish fed nGM maize and with the reference diet group. Fish fed GM maize showed significantly lower catalase (CAT) activity in liver compared with fish fed nGM maize and to the reference diet group. In contrast, CAT activity in distal intestine was significantly higher for fish fed GM maize compared with fish fed reference diet. Protein level of heat shock protein 70 (HSP70) in liver was significantly higher in fish fed GM maize compared with fish fed the reference diet. No diet-related differences were found in normalized gene expression of SOD, CAT or HSP70 in liver or distal intestine. Normalized gene expression of interleukin-1 beta in spleen and head-kidney did not vary significantly between diet groups. Interestingly, fish fed high GM maize showed a significantly larger proportion of plasma granulocytes, a significantly larger sum of plasma granulocyte and monocyte proportions, but a significantly smaller proportion of plasma lymphocytes, compared with fish fed high nGM maize. In conclusion, Atlantic salmon fed GM maize showed some small changes in stress protein levels and activities, but none of these changes were comparable to the normalized gene expression levels analysed for these stress proteins. GM maize seemed to induce significant changes in white blood cell populations which are associated with an immune response. [source] Modulation of F1 hybrid stature without altering parent plants through trans-activated expression of a mutated rice GAI homologuePLANT BIOTECHNOLOGY JOURNAL, Issue 2 2005Ning Su Summary Hybrid breeding, by taking advantage of heterosis, brings about many superior properties to the F1 progeny. However, some properties, such as increased plant height, are not desirable for agronomic purposes. To specifically counter the height increase associated with hybrid progeny, we employed an Arabidopsis model and tested a trans-activation system for specifically expressing a mutated GAI gene only in the F1 hybrid plants to reduce plant stature. A transcriptional activator, the Gal4 DNA-binding domain fused to the acidic activation domain of herpes simplex virus VP16 protein, driven by a maize ubiquitin promoter, was introduced in one parental line. A rice GAI homologue with an N-terminal deletion of the DELLA domain, driven by a promoter that is responsive to the transcriptional activator, was transferred into another parental line. After genetic crossing, trans-activation of the GAI mutant gene resulted in a dwarf phenotype. Over 50 pair-wise crosses between the parental lines were performed, and analyses suggested that the percentage of F1 progeny exhibiting dwarfism ranged from about 25% to 100%. Furthermore, the dwarfism trait introduced in F1 progeny did not seem to affect total seed yield. Our result suggests the feasibility of manipulating F1 hybrid progeny traits without affecting parent plants or the agronomic property of the progeny. [source] Genotype-dependent response to carbon availability in growing tomato fruitPLANT CELL & ENVIRONMENT, Issue 7 2010MARION PRUDENT ABSTRACT Tomato fruit growth and composition depend on both genotype and environment. This paper aims at studying how fruit phenotypic responses to changes in carbon availability can be influenced by genotype, and at identifying genotype-dependent and -independent changes in gene expression underlying variations in fruit growth and composition. We grew a parental line (Solanum lycopersicum) and an introgression line from Solanum chmielewskii harbouring quantitative trait loci for fresh weight and sugar content under two fruit loads (FL). Lowering FL increased fruit cell number and reduced fruit developmental period in both genotypes. In contrast, fruit cell size was increased only in the parental line. Modifications in gene expression were monitored using microarrays and RT-qPCR for a subset of genes. FL changes induced more deployments of regulation systems (transcriptional and post-transcriptional) than massive adjustments of whole primary metabolism. Interactions between genotype and FL occurred on 99 genes mainly linked to hormonal and stress responses, and on gene expression kinetics. Links between gene expression and fruit phenotype were found for aquaporin expression levels and fruit water content, and invertase expression levels and sugar content. In summary, the present data emphasized age- and genotype-dependent responses of tomato fruit to carbon availability, at phenotypic as well as gene expression level. [source] Unintended changes in protein expression revealed by proteomic analysis of seeds from transgenic pea expressing a bean ,-amylase inhibitor genePROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 18 2009Hancai Chen Abstract Seeds of genetically modified (GM) peas (Pisum sativum L.) expressing the gene for ,-amylase inhibitor-1 (,AI1) from the common bean (Phaseolus vulgaris L. cv. Tendergreen) exhibit resistance to the pea weevil (Bruchus pisorum). A proteomic analysis was carried out to compare seeds from GM pea lines expressing the bean ,AI1 protein and the corresponding ,AI1-free segregating lines and non-GM parental line to identify unintended alterations to the proteome of GM peas due to the introduction of the gene for ,AI1. Proteomic analysis showed that in addition to the presence of ,AI1, 33 other proteins were differentially accumulated in the ,AI1-expressing GM lines compared with their non-GM parental line and these were grouped into five expression classes. Among these 33 proteins, only three were found to be associated with the expression of ,AI1 in the GM pea lines. The accumulation of the remaining 30 proteins appears to be associated with Agrobacterium -mediated transformation events. Sixteen proteins were identified after MALDI-TOF-TOF analysis. About 56% of the identified proteins with altered accumulation in the GM pea were storage proteins including legumin, vicilin or convicilin, phaseolin, cupin and valosin-containing protein. Two proteins were uniquely expressed in the ,AI1-expressing GM lines and one new protein was present in both the ,AI1-expressing GM lines and their ,AI1-free segregating lines, suggesting that both transgenesis and transformation events led to demonstrable changes in the proteomes of the GM lines tested. [source] Microsatellite markers associated with quantitative trait loci controlling antibody response to Escherichia coli and Salmonella enteritidis in young broilersANIMAL GENETICS, Issue 6 2002R. Yunis A unique resource population was produced to facilitate detection of microsatellite markers associated with quantitative trait loci controlling antibody (Ab) response in broiler chickens. Three F1 males were produced by mating two lines divergently selected on Ab response to Escherichia coli vaccination. Each F1 male was mated with females from four genetic backgrounds: F1, high-Ab line (HH), low-Ab line and commercial line, producing three resource families, each with four progeny types. About 1700 chicks were immunized with E. coli and Salmonella enteritidis vaccines. Selective genotyping was conducted on the individuals with highest or lowest average Ab to E. coli and S. enteritidis within each progeny type in each sire family. Twelve markers were significantly associated with Ab to E. coli and six of them were also associated with Ab to S. enteritidis, mostly exhibiting a similar low effect (, 0.35 phenotypic SD) in all progeny types. Four markers exhibited a highly significant and much larger effect (,1.7 SD), but only in progeny of females from the HH, suggesting that a backcross to the high parental line should be preferred over the commonly used F2 population. Results from two markers suggested a quantitative trait locus on chromosome 2 around 400 cM. The marker MCW0083, significant in two sire families, is closely linked to the bone morphogenetic protein 2 (BMP2) gene, known to be associated with the control of T-cell transformation in humans. [source] Distal intestinal gene expression in Atlantic salmon (Salmo salar L.) fed genetically modified maizeAQUACULTURE NUTRITION, Issue 1 2009M.K. FRØYSTAD-SAUGEN Abstract In the current experiment, RNA was isolated from the distal intestine (DI) of Atlantic salmon-fed fishmeal-based diets containing either genetically modified (GM) maize (Bt maize, Mon810®, Monsanto Company, St. Louis, Missouri, USA) or its conventional near-isogenic parental line (non-GM) for 82 days, both at 300 g kg,1 inclusion. From a suppression subtractive hybridization (SSH) cDNA library, 192 clones with similarity to both known and novel Atlantic salmon sequences were identified. Real-time PCR was used to study the differential expression of 10 clones between the dietary groups. Expression of a clone showing high protein similarity to proton-dependent high-affinity oligopeptide transporter was significantly upregulated in fish-fed GM maize compared with fish-fed non-GM maize. No significant differences in expression were observed for the nine other clones showing similarity to the following proteins: heat shock protein 90B, procathepsin B, interferon gamma-inducible protein 30, ferritin heavy subunit, serum lectin isoform/C-type mannose-binding lectin, fatty acid-binding protein/gastrotropin, ATP synthase [H+ transporting, mitochondrial F0 complex, subunit c (ATPSYNT)], sonic hedgehog and translationally controlled tumour protein. In conclusion, only minor differences in DI transcriptional gene expression was observed between fish fed the GM and non-GM maize diets. [source] Gene expression in distal intestine of Atlantic salmon (Salmo salar L.) fed genetically modified soybean mealAQUACULTURE NUTRITION, Issue 3 2008M.K. FRØYSTAD Abstract Limited availability of fishmeal leads to exploration of alternative protein sources like soybean meal (SBM). During the last decade, genetically modified (GM) plants have been introduced to the production of soybean crops. In the current experiment RNA was isolated from the distal intestinal section of Atlantic salmon fed either GM SBM or its near-isogenic parental line (non-GM), both at 30% inclusion. From a suppression subtractive hybridization cDNA library, 95 clones were sequenced. Clones with similarity to both known Atlantic salmon genes and novel Atlantic salmon sequences were identified. Real-time polymerase chain reaction was used to study differential expression of seven clones between the dietary groups. The clones were selected based on their relevance to intestinal immune responses and nutrient metabolism. Expression of a serum lectin-like clone was down-regulated in the GM group compared with the non-GM group. No differential expression was observed for six other clones with similarity to actin-related protein 2/3 complex-subunit 3, cysteine-rich intestinal protein, fatty acid binding protein/gastrotropin, ferritin heavy subunit, anterior gradient protein and peptide transporter. In conclusion, only minor differences in distal intestine transcriptional gene expression were observed between fish fed the diets with the non-GM and GM varieties. [source] Nutritional, physiological, and histological responses in Atlantic salmon, Salmo salar L. fed diets with genetically modified maizeAQUACULTURE NUTRITION, Issue 3 2007G.-I. HEMRE Abstract The objective of this study was to evaluate whether standard fish meal diets prepared with increasing levels of genetically modified (GM; 150 and 300 g kg,1) maize (event MON810®) as a starch source, showed any nutritional or physiological adverse effects on Atlantic salmon, Salmo salar L. postsmolt. The diets with low or high inclusions of GM maize and its near-isogenic parental line (nongenetically modified; nGM maize), were balanced with Suprex maize (Reference) to obtain compositional equivalency of diet starch, sugars and all other nutrients. Total starch level in all diets was 160 g kg,1. After 82 days of feeding, fish growth was high in all groups, however fish fed the GM maize showed slight but significant lower feed intake, which was followed by slight but significant lower specific growth rate and final body weights, compared with fish fed nGM maize, none of the groups varied significantly from fish fed the Reference diet. There was no variation in feed conversion ratios (FCR), protein and lipid efficiency ratios (PER and LER), or protein- and lipid-productive values (PPV and LPV) in this study. No significant effect of maize type was detected on apparent digestibility coefficients (ADC) of dry matter, protein or lipid. Hematological analysis and plasma nutrients varied within normal ranges for Atlantic salmon in all diet groups, except for somewhat elevated aspartate aminotransferase (ASAT) values in all groups. Hepatosomatic index (HSI) with values ranging from 1.37 to 1.60, was significantly higher for the high GM maize group compared with the high nGM maize group but not when compared with the Reference diet group. Lowered spleen (SSI) and head-kidney somatic indices (H-KSI) were registered when fed GM compared with nGM maize, the Reference treatment was however, equal to both. Distal intestine somatic index (DISI) was significantly higher for GM maize-fed fish compared with nGM maize-fed fish, but not significantly different from the Reference diet group. Histological evaluation of the mid- and distal intestine, liver, spleen and head-kidney did not reveal any diet-related morphological changes. Maltase activities in the mid- and distal intestinal tissue homogenates were affected by diet, the fish fed high GM maize having higher activities compared with high nGM maize-fed fish. Leucine aminopeptidase (LAP) and alkaline phosphatase (AP) activities were not affected by diet. Sodium-dependent d -glucose uptake in brush border membrane vesicles (BBMV) isolated from pyloric caeca of fish fed high GM maize was significantly higher than that found in fish fed the analogous diet with high nGM maize. Based on the present findings, the conclusions made are: Atlantic salmon smolts fed GM maize (event MON810®), its near-isogenic parental line and suprex maize (Reference diet), all resulted in high growth rates, ADC and feed utilization. Health, when evaluated by means of mortality (low), normal ranges of blood and plasma parameters, except somewhat elevated ASAT values and minor variations in organ sizes, were considered good in all diet groups. The changes in the glucose transport mechanism and intestinal maltase enzyme activity in the gastrointestinal tract warrant further studies. [source] Patterns of spread in an orthotopic mouse model of bladder cancerBJU INTERNATIONAL, Issue 2006J.P. BRENNAN Purpose:, To develop an orthotopic model of muscle-invasive transitional cell carcinoma (TCC) of the bladder which models primary tumour growth and metastasis. Methodology:, Cell lines were derived from the TCC cell line T24 (Tsu-Pr1) using in vivo selection for metastatic ability (Chaffer et al. Clin Exp Metastasis 2005; 22(2): 115,25). Each of these cell lines (Tsu-Pr1 and sub-lines, B1 and B2) was then injected intramurally into the mouse bladder wall (n = 25 × 3). The cell lines were also injected intravesically and intraperitoneally (n = 15 × 3 in each group). Results:, There were no differences between the three sub-lines in primary tumour formation, presence of macroscopic metastases and survival. This model produced more macroscopic and lymph node metastases in comparison with other orthotopic models reported in the literature. After intraperitoneal injection, the B2 cell line produced a higher number of discrete intra-abdominal masses in comparison with the parental line. This is likely to be related to the phenotype of the cells with parental cells being more mesenchymal, versus the B2 sub-line, which has more epithelial characteristics. Conclusion:, The TSU-Pr1 series is a useful, clinically relevant model of muscle-invasive TCC. In addition, this model may also provide insights into the role of mesenchymal-epithelial transition in the metastatic process. [source] Up-regulation of CD147 and matrix metalloproteinase-2, -9 induced by P-glycoprotein substrates in multidrug resistant breast cancer cellsCANCER SCIENCE, Issue 11 2007Qing-Quan Li Treatment of animals bearing multidrug resistant (MDR) tumor cells with P-glycoprotein (P-gp) substrates could worsen host survival. It is assumed that this is due to increased tumor metastasis. To clarify the mechanism(s) underlying this observation, the MDR human breast cancer cell line, MCF-7/AdrR, and its sensitive parental line, MCF-7, was treated with various concentrations of P-gp substrate drugs (vincristine, paclitoxel, adriamycin) and a P-gp non-substrate drug (bleomycin) in serum-free media. Increased production of CD147, and matrix metalloproteinases (MMP)-2, -9 was observed only in MDR cancer cells exposed to P-gp substrates, as determined using real-time polymerase chain reaction, western blotting and zymography. Correspondingly, P-gp substrates significantly enhanced the in vitro invasion abilities of MCF-7/Adr cells. It was also found that the drug-induced promotion of CD147, and MMP-2, -9 was consistent with increased expression of epidermal growth factor receptor (EGFR) and that inhibition of either EGFR or P-gp activity could significantly interrupt the downstream effects, and so inhibit in vitro invasion abilities motivated by P-gp substrates. These results imply that treatment of MDR tumors with P-gp substrates could adversely affect therapeutic outcomes through modulating the production of CD147, MMP-2, -9, and EGFR, and suggest that this effect may be initiated by the transporter function of P-gp. (Cancer Sci 2007; 98: 1767,1774) [source] The role of various Bcl-2 domains in the anti-proliferative effect and modulation of cellular glutathione levels: a prominent role for the BH4 domainCELL PROLIFERATION, Issue 1 2003R. W. M. Hoetelmans Reduced cell proliferation and increased levels of cellular glutathione (GSH) are characteristic for cells that overexpress the anti-apoptotic Bcl-2 protein. We investigated the influence of various Bcl-2 domains on both these characteristics. Rat CC531 colorectal cancer cells were stably transfected with the human bcl- 2 gene (CCbcl2 cells) or with bcl- 2 gene constructs missing a coding sequence for a func-tional domain, BH1 (CC,BH1 cells), BH3 (CC,BH3 cells), BH4 (CC,BH4 cells) or the transmembrane region (CC,TM cells). We measured GSH levels in exponentially and confluent growing bcl- 2-transfected cell populations. The fraction of S-phase cells during exponential growth was significantly reduced in CCbcl2, CC,BH1, CC,BH3, and CC,TM cells compared with parental CC531, neo-transfected CC531 and CC,BH4 cells. GSH levels in these bcl -2 transfectants were significantly higher than in the parental line measured at 50% confluence; at 100% confluence they reached a similar level as found in parental cells. Independently from the presence of BH1, BH3 or TM domains, overexpression of Bcl-2 reduces cellular proliferation under conditions of increased GSH levels. This apparent link is lost in CC,BH4 cells; these cells are not reduced in cellular proliferation and harbour significantly higher GSH levels than found in the other transfectants. Studies on the subcellular localization revealed an extremely low expression of the Bcl-2 protein lacking the N-terminal BH4 domain in nuclear fractions. Nuclear translocation of Bcl-2 requires the presence of the BH4 domain and seems prominent in reducing cellular proliferation. [source] Host-related life history traits in interspecific hybrids of cactophilic DrosophilaENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 1 2008E. M. Soto Abstract In the genus Drosophila (Diptera: Drosophilidae), interspecific hybridization is a rare phenomenon. However, recent evidence suggests a certain degree of introgression between the cactophilic siblings Drosophila buzzatii Patterson & Wheeler and Drosophila koepferae Fontdevila & Wasserman. In this article, we analyzed larval viability and developmental time of hybrids between males of D. buzzatii and females of D. koepferae, raised in media prepared with fermenting tissues of natural host plants that these species utilize in nature as breeding sites. In all cases, developmental time and larval viability in hybrids was not significantly different from parental lines and, depending on the cross, hybrids developed faster than both parental species or than the slowest species. When data of wing length were included in a discriminant function analysis, we observed that both species can be clearly differentiated, while hybrids fell in two categories, one intermediate between parental species and the other consisting of extreme phenotypes. Thus, our results point out that hybrid fitness, as measured by developmental time and viability, is not lower than in the parental species. [source] Evaluation of Drought-Related Traits and Screening Methods at Different Developmental Stages in Spring BarleyJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 5 2008F. Szira Abstract Despite intensive research and breeding efforts, the physiological and quantitative genetic bases of drought tolerance are still poorly understood. The comparison of results obtained from different sources is also complex, because different testing methods may lead to controversial conclusions. This report discusses various drought stress experiments (hydroponics and in soil) in which the plant tolerance was studied at different developmental stages. Tests were performed in the germination, seedling and adult plant stages on the parental lines of five well-known barley-mapping populations. The results suggest that drought tolerance is a stage-specific trait and changes during the life cycle. The effect of drought stress depended not only on the duration and intensity of water deficiency, but also on the developmental phase in which it began. To induce the same type of stress and to obtain comparable tolerance information from the replications, it is recommended that drought stress should be induced at the same growth stage. Correlations between the traits, commonly associated with improved drought resistance (high relative water content under stress, proline accumulation, osmoregulation) with stress tolerance indexes, are also presented, while the advantages and disadvantages of the most frequently used screening methods are discussed. [source] A novel form of resistance in rice to the angiosperm parasite Striga hermonthicaNEW PHYTOLOGIST, Issue 1 2006A. L. Gurney Summary ,,The root hemiparasitic weed Striga hermonthica is a serious constraint to grain production of economically important cereals in sub-Saharan Africa. Breeding for parasite resistance in cereals is widely recognized as the most sustainable form of long-term control; however, advances have been limited owing to a lack of cereal germplasm demonstrating postattachment resistance to Striga. ,,Here, we identify a cultivar of rice (Nipponbare) that exhibits strong postattachment resistance to S. hermonthica; the parasite penetrates the host root cortex but does not form parasite,host xylem,xylem connections. ,,In order to identify the genomic regions contributing to this resistance, a mapping population of backcross inbred lines between the resistant (Nipponbare) and susceptible (Kasalath) parents were evaluated for resistance to S. hermonthica. ,,Composite interval mapping located seven putative quantitative trait loci (QTL) explaining 31% of the overall phenotypic variance; a second, independent, screen confirmed four of these QTL. Relative to the parental lines, allelic substitutions at these QTL altered the phenotype by at least 0.5 of a phenotypic standard deviation. Thus, they should be regarded as major genes and are likely to be useful in breeding programmes to enhance host resistance. [source] Ascorbate-dependent hydrogen peroxide detoxification and ascorbate regeneration during germination of a highly productive maize hybrid: Evidence of an improved detoxification mechanism against reactive oxygen speciesPHYSIOLOGIA PLANTARUM, Issue 1 2000Laura De Gara Ascorbate content and the activities of some key enzymes involved in the detoxification from reactive oxygen species were investigated in germinated embryos of two Zea mays L. inbred lines (B73 and Mo17) and of their heterotic F1 hybrid (B73×Mo17). The F1 hybrid showed a higher ascorbate biosynthetic capability owing to a higher activity of l -galactono- , -lactone dehydrogenase (EC 1.6.5.4), the last enzyme in ascorbate biosynthesis. Ascorbate peroxidase (EC 1.11.1.11), ascorbate free radical reductase (EC 1.6.5.4) and dehydroascorbate reductase (EC 1.8.5.1) activities were much higher in the F1 hybrid than in either inbred line, whereas catalase (EC 1.11.1.6) activity was similar in the three genotypes. Native polyacrylamide gel electrophoresis (PAGE) analysis showed three forms of cytosolic ascorbate peroxidase, both in parental lines and in the F1 hybrid. On the other hand, a complex pattern of proteins with dehydroascorbate reductase activity was observed, with the hybrid combining the different dehydroascorbate-reducing proteins expressed by the inbred lines. The possible involvement of the enzymes of the ascorbate system in the phenomenon of hybrid vigour is discussed. [source] Reverse breeding: a novel breeding approach based on engineered meiosisPLANT BIOTECHNOLOGY JOURNAL, Issue 9 2009Rob Dirks Summary Reverse breeding (RB) is a novel plant breeding technique designed to directly produce parental lines for any heterozygous plant, one of the most sought after goals in plant breeding. RB generates perfectly complementing homozygous parental lines through engineered meiosis. The method is based on reducing genetic recombination in the selected heterozygote by eliminating meiotic crossing over. Male or female spores obtained from such plants contain combinations of non-recombinant parental chromosomes which can be cultured in vitro to generate homozygous doubled haploid plants (DHs). From these DHs, complementary parents can be selected and used to reconstitute the heterozygote in perpetuity. Since the fixation of unknown heterozygous genotypes is impossible in traditional plant breeding, RB could fundamentally change future plant breeding. In this review, we discuss various other applications of RB, including breeding per chromosome. [source] A metabolomic study of substantial equivalence of field-grown genetically modified wheatPLANT BIOTECHNOLOGY JOURNAL, Issue 4 2006John M. Baker Summary The ,substantial equivalence' of three transgenic wheats expressing additional high-molecular-weight subunit genes and the corresponding parental lines (two lines plus a null transformant) was examined using metabolite profiling of samples grown in replicate field trials on two UK sites (Rothamsted, Hertfordshire and Long Ashton, near Bristol) for 3 years. Multivariate comparison of the proton nuclear magnetic resonance spectra of polar metabolites extracted with deuterated methanol,water showed a stronger influence of site and year than of genotype. Nevertheless, some separation between the transgenic and parental lines was observed, notably between the transgenic line B73-6-1 (which had the highest level of transgene expression) and its parental line L88-6. Comparison of the spectra showed that this separation resulted from increased levels of maltose and/or sucrose in this transgenic line, and that differences in free amino acids were also apparent. More detailed studies of the amino acid composition of material grown in 2000 were carried out using gas chromatography-mass spectrometry. The most noticeable difference was that the samples grown at Rothamsted consistently contained larger amounts of acidic amino acids (glutamic, aspartic) and their amides (glutamine, asparagine). In addition, the related lines, L88-6 and B73-6-1, both contained larger amounts of proline and ,-aminobutyric acid when grown at Long Ashton than at Rothamsted. The results clearly demonstrate that the environment affects the metabolome and that any differences between the control and transgenic lines are generally within the same range as the differences observed between the control lines grown on different sites and in different years. [source] Modulation of F1 hybrid stature without altering parent plants through trans-activated expression of a mutated rice GAI homologuePLANT BIOTECHNOLOGY JOURNAL, Issue 2 2005Ning Su Summary Hybrid breeding, by taking advantage of heterosis, brings about many superior properties to the F1 progeny. However, some properties, such as increased plant height, are not desirable for agronomic purposes. To specifically counter the height increase associated with hybrid progeny, we employed an Arabidopsis model and tested a trans-activation system for specifically expressing a mutated GAI gene only in the F1 hybrid plants to reduce plant stature. A transcriptional activator, the Gal4 DNA-binding domain fused to the acidic activation domain of herpes simplex virus VP16 protein, driven by a maize ubiquitin promoter, was introduced in one parental line. A rice GAI homologue with an N-terminal deletion of the DELLA domain, driven by a promoter that is responsive to the transcriptional activator, was transferred into another parental line. After genetic crossing, trans-activation of the GAI mutant gene resulted in a dwarf phenotype. Over 50 pair-wise crosses between the parental lines were performed, and analyses suggested that the percentage of F1 progeny exhibiting dwarfism ranged from about 25% to 100%. Furthermore, the dwarfism trait introduced in F1 progeny did not seem to affect total seed yield. Our result suggests the feasibility of manipulating F1 hybrid progeny traits without affecting parent plants or the agronomic property of the progeny. [source] Microspore mutagenesis of Brassica species for fatty acid modifications: a preliminary evaluationPLANT BREEDING, Issue 5 2008A. M. R. Ferrie Abstract A microspore mutagenesis protocol was developed for Brassica rapa, Brassica napus and Brassica juncea for the production of double haploid lines with novel fatty acid profiles in the seed oil. Freshly isolated Brassica microspores were first cultured with ethyl methane sulphonate (EMS) for 1.5 h. The EMS was removed and the microspores were then cultured according to the standard Brassica microspore culture protocol. This protocol was used to generate over 80 000 Brassica haploid/double haploid plants. Field evaluation of B. napus and B. juncea double haploids was conducted between 2000 and 2003. Fatty acid analysis of the B. napus double haploid lines showed that saturated fatty acid proportions ranged from 5.0% to 7.7%. For B. juncea, saturate proportions ranged from 5.4% to 9.5%. Of the 7000 B. rapa lines that were analysed, 197 lines had elevated oleic acid (>55%), 69 lines had reduced ,-linolenic acid (<8%) and 157 lines had low saturated fatty acid proportions (<5%), when compared with the parental lines. [source] Comparative evaluation of exotic and adapted germplasm of spring wheat for floral characteristics in the Indo-Gangetic Plains of northern IndiaPLANT BREEDING, Issue 6 2007S. K. Singh Abstract Four hundred spring wheat genotypes, comprising exotic and indigenous germplasm and adapted cultivars for commercial cultivation, were investigated during four crop seasons for six floral characteristics related to outcrossing behaviour. Genetic variability and heritability were investigated along with phenotypic correlation coefficients among these characteristics. A significant quantitative variation existed among the characteristics in all three groups. High heritability for stigma length, openness of florets, anther extrusion and duration of floral opening indicated that selection for these characteristics may be effective. The adapted cultivars were found more promising than the exotic and indigenous germplasm. Most of the characteristics showed significantly positive correlation with each other and high correlation was observed between anther and stigma length, and anther extrusion and duration of floral opening. Superiority of varietal mixtures and segregating generations (F3 and F4) of two crosses over parental lines suggested that heterozygosity and heterogeneity can provide yield advantages. Germplasm lines possessing superior expression of floral characteristics may be used to improve yielding ability through enhanced heterozygosity or the development of hybrids. [source] Genetic diversity among parental lines of Indica hybrid rice (Oryza sativa L.) in China based on coefficient of parentagePLANT BREEDING, Issue 6 2006S. Wang Abstract Genetic diversity constitutes the raw material for plant improvement, and provides protection against genetic vulnerability to biotic and abiotic stresses. Diversity of parental lines of indica hybrid rice in China is not well-characterized. The major objective of this study was to quantify genetic diversity of Chinese parental lines of hybrid rice via coefficient of parentage (COP). All 100 parental lines of hybrid rice widely used in hybrid breeding and commercial production during 1976,2003 were studied by COP analysis. The mean COP for the 100 parental lines was low (0.056), indicating a potentially high degree of diversity in Chinese hybrid rice breeding. Forty-nine percent of all pairs of parental lines were completely unrelated by pedigree data. The low mean COP for the parental lines was attributed to a continual incorporation of exotic germplasm (wild rice, japonica and javanica etc.) into the genetic base over time, to the introduction of foreign germplasm from the Philippines (International Rice Research Institute), Korea, the United States, Thailand, and Guyana as breeding stock. The mean COP from 1976 to 1990 was twice as much as that from 1990 to 2003. Cluster analysis was an effective method to discriminate diversity, ten clusters were identified, and maintainer lines, restorer lines and other parental lines with special genetic background were clearly grouped. In addition, restorer lines were further divided into 11 sub-clusters, which basically was in agreement with hybrid rice breeding. Among ten provinces, Hunan, Sichuan and Fujian were outstanding for breeding 54 of 100 parental lines in hybrid rice production, and the genetic diversity of parental lines in Fujian, Sichuan,Guangxi, Hunan and Jiangsu were all narrower than that in Hubei, Guangdong, Zhejiang and Jiangxi. The result of coefficient of parentage analysis for 100 parental lines may promote the management of parental diversity and hybrid rice breeding in China. [source] Identification and characterization of microsatellites in eggplantPLANT BREEDING, Issue 3 2003T. Nunome Abstract The potential of microsatellite markers for use in genetic studies in eggplant, Solanum melongena, has been evaluated. A genomic library of eggplant was screened for GA and GT repeat motifs to isolate microsatellite clones. The frequency of each repeat motif in the eggplant genome was found to be every 3200 kb for GA repeats and every 820 kb for GT repeats. Sixty-one per cent of GT repeats were found to directly flank AT repeats. A total of 37 polymerase chain reaction (PCR) primer pairs were designed, 23 of which amplified a single product or several products. The level of microsatellite polymorphism was evaluated by using S. melongena lines and related Solanum species. Two to six alleles per primer pair were displayed in the S. melongena lines and two to 13 alleles were displayed in the Solanum relatives. Seven microsatellites showed polymorphism between parental lines of the mapping population and segregated in a codominant Mendelian manner. These microsatellite loci were distributed throughout the linkage map. [source] Asymmetric allele-specific expression in relation to developmental variation and drought stress in barley hybridsTHE PLANT JOURNAL, Issue 1 2009Maria Von Korff Summary In the present study, we analysed allele-specific expression (ASE) in the selfing species barley to assess the frequency of cis -acting regulatory variation and the effects of genetic background, developmental differences and drought stress on allelic expression levels. We measured ASE ratios in 30 genes putatively involved in stress responses in five hybrids and their reciprocals, namely Hordeum spontaneum 41-1/Alexis (HAl), Hordeum spontaneum 41-1/Arta (HAr), Sloop/WI3408 (SW), Tadmor/Sloop (TS) and Tadmor/WI3408 (TW). In order to detect cis -acting variation related to drought and developmental changes, the barley hybrids were grown under control and water-limited conditions, and leaf tissue was harvested at two developmental stages. The analysis demonstrated that more than half of the genes measured (63%) showed allelic differences in expression of up to 19-fold due to cis -regulatory variation in at least one cross by treatment/stage combination. Drought stress induced changes in allelic expression ratios, indicating differences between drought responsive cis -elements. In addition, ASE differences between developmental stages suggested the presence of cis -acting elements interacting with developmental cues. We were also able to demonstrate that the levels and frequency of allelic imbalance and hence differences in cis -regulatory elements are correlated with the genetic divergence between the parental lines, but may also arise as an adaptation to diverse habitats. Our findings suggest that cis -regulatory variation is a common phenomenon in barley, and may provide a molecular basis of transgression. Differential expression of near-isogenic members of the same gene family could potentially result in hybrid lines out performing their parents in terms of expression level, timing and response to developmental and environmental cues. Identification and targeted manipulation of cis -regulatory elements will assist in breeding improved crops with a better adaptation to changing environments. [source] Alloplasmic effects on mitochondrial transcriptional activity and RNA turnover result in accumulated transcripts of Arabidopsis orfs in cytoplasmic male-sterile Brassica napusTHE PLANT JOURNAL, Issue 4 2005Matti Leino Summary Mitochondrial transcription was investigated in a cytoplasmic male-sterile (CMS) Brassica napus line with rearranged mitochondrial (mt) DNA mostly inherited from Arabidopsis thaliana. The transcript patterns were compared with the corresponding male-fertile progenitors, B. napus and A. thaliana, and a fertility-restored line. Transcriptional activities, gene stoichiometry and transcript steady-state levels were analysed for all protein and rRNA coding genes and for several orfs present in the A. thaliana mitochondrial genome. The transcriptional activities were highly variable when comparing the parental species, while the CMS and restored lines displayed similar activities. For several ribosomal protein genes transcriptional activity was reduced while it was increased for orf139 in comparison with the parental species. The differences in transcriptional activity observed could be related to differences in relative promoter strength, as gene stoichiometry between lines was very limited. Transcript steady-state levels were more homogenous than the transcriptional activities demonstrating RNA turnover as a compensating mechanism. In the CMS line higher transcript abundance and novel transcript patterns in comparison with the parental lines were found for several genes. Of those, the transcripts for orf139, orf240a and orf294 were less abundant in the fertility-restored line. These putative CMS-associated transcripts were mapped by cRT-PCR. In conclusion we show that (mt) DNA from A. thaliana was non-correctly transcribed and processed/degraded in the B. napus nuclear background. Furthermore, the introgressed nuclear A. thaliana DNA in the fertility-restored line contributes to a more rapid degradation of transcripts accumulated from A. thaliana derived orfs in the CMS line. [source] Experimental population design for estimation of dominant molecular marker effect on egg-production traitsANIMAL GENETICS, Issue 5 2003M. G. Kaiser Summary A potential limitation of the use of a dominant molecular marker system such as DNA fingerprinting (DFP) is the inability to distinguish homozygous from heterozygous allele state in an individual, and a resulting inaccuracy in estimating effects of the marker alleles. The objective of this study was to accurately estimate the effect of DFP markers on egg-production traits. A BC1 population was produced from two distinct layer lines. Four DFP bands, each originating predominantly in one of the two parental lines, were evaluated for linkage with egg-production quantitative trait loci in the BC1 population. The egg-production traits consisted of eight early period and seven late period measurements. Eight marker-trait linkages were identified out of 60 total statistical tests. By utilizing information on frequency of DFP bands in two parental lines, selecting F1 sires with DFP bands present, and backcrossing to the line lacking these bands, the population design allowed definitive identification of the DFP zygosity in the BC1 resource population hens. In this manner, accurate estimates of marker allele effects on egg-production traits were obtained from the dominant marker system of DNA fingerprinting. [source] |