bluuebunny/crossref_metadata_2025_split huggingface dataset:
T-DNA mutagenesis in the model plant
Medicago truncatula
: is it efficient enough for legume molecular genetics?
Authors: Brocard L. , Schultze M. , Kondorosi A. , Ratet P. 
Published: January 2007

Abstract

The development of efficient transformation protocols in several legume species has opened the possibility to use T-DNA insertional mutagenesis to investigate legume-specific processes such as symbiosis. A T-DNA mutagenesis approach was initiated in the model legume
Medicago truncatula
by constructing a small collection of 1000
M. truncatula
T-DNA lines, using in vitro-mediated transformation-regeneration protocols. In this T-DNA collection, mutant phenotypes were observed but generally did not result from the disruption of genes by the T-DNA but most probably from somaclonal mutations induced by the in vitro regeneration process or by unsuccessful T-DNA integration events resulting in small (undetectable) insertions or deletions in the genome of the regenerated plants. In addition, a promoter trap approach was also not very successful for gene discovery because aberrant gene fusions were observed in this collection. Therefore, the T-DNA mutagenesis approach in
M. truncatula
seems to be limited by the lack of an efficient in planta transformation protocol that would allow the generation of a large mutant collection suitable for reverse genetic studies. Thus, there is a need for the development of alternative tools for efficient gene disruption in legumes.
The ecology of non-native invasive plant species: are there consistent patterns?
Authors: Inderjit Inderjit , Drake J. A. 
Published: January 2007

Abstract

Non-native invasive species are defined as those naturalized species that are new to a particular region and produce reproductive offspring at considerable distance from their native land. Invasive plants can be introduced accidentally (e.g.
Parthenium hysterophorus
and
Chromolaena odorata
) or deliberately (e.g.
Lantana camara
and
Prosopis juliflora
) and can have profound population, community and ecosystem-level effects. The aim of this paper is to examine how ecological attributes such as disturbance, species diversity and species richness influence invasion patterns. Are there parameters that retrospectively explain a significant amount of variation in invasion outcome? How often do the same parameters correlate with invasion success or failure among different communities, and can these variables be implemented in general models that aim to predict the likelihood of plant invasions? We feel that the chances of detecting any broadly applicable relationship (i.e. general factors that governs habitat invasibility or invasive success) are remote given contemporary approaches to biological invasions. Our conclusion is based on the nature of complex dynamical systems, where generality is possible at some levels of organization and observation but not others. Precise prediction requires a case-by-case study, and even then the outcome of biological invasions can be surprising.
Conservation, Convergence, and Divergence of Light-Responsive, Circadian-Regulated, and Tissue-Specific Expression Patterns during Evolution of the Arabidopsis GATA Gene Family
Authors: Manfield Iain W. , Devlin Paul F. , Jen Chih-Hung , Westhead David R. , Gilmartin Philip M. 
Published: January 2007

Abstract
In vitro analyses of plant GATA transcription factors have implicated some proteins in light-mediated and circadian-regulated gene expression, and, more recently, the analysis of mutants has uncovered further diverse roles for plant GATA factors. To facilitate function discovery for the 29 GATA genes in Arabidopsis (Arabidopsis thaliana), we have experimentally verified gene structures and determined expression patterns of all family members across adult tissues and suspension cell cultures, as well as in response to light and signals from the circadian clock. These analyses have identified two genes that are strongly developmentally light regulated, expressed predominantly in photosynthetic tissue, and with transcript abundance peaking before dawn. In contrast, several GATA factor genes are light down-regulated. The products of these light-regulated genes are candidates for those proteins previously implicated in light-regulated transcription. Coexpression of these genes with well-characterized light-responsive transcripts across a large microarray data set supports these predictions. Other genes show additional tissue-specific expression patterns suggesting novel and unpredicted roles. Genome-wide analysis using coexpression scatter plots for paralogous gene pairs reveals unexpected differences in cocorrelated gene expression profiles. Clustering the Arabidopsis GATA factor gene family by similarity of expression patterns reveals that genes of recent descent do not uniformly show conserved current expression profiles, yet some genes showing more distant evolutionary origins have acquired common expression patterns. In addition to defining developmental and environmental dynamics of GATA transcript abundance, these analyses offer new insights into the evolution of gene expression profiles following gene duplication events.
Abscisic Acid and Stress Signals InduceViviparous1Expression in Seed and Vegetative Tissues of Maize
Authors: Cao Xueyuan , Costa Liliana M. , Biderre-Petit Corinne , Kbhaya Bouchab , Dey Nrisingha , Perez Pascual , McCarty Donald R. , Gutierrez-Marcos Jose F. , Becraft Philip W. 
Published: January 2007

AbstractViviparous1 (Vp1) encodes a B3 domain-containing transcription factor that is a key regulator of seed maturation in maize (Zea mays). However, the mechanisms of Vp1 regulation are not well understood. To examine physiological factors that may regulate Vp1 expression, transcript levels were monitored in maturing embryos placed in culture under different conditions. Expression of Vp1 decreased after culture in hormone-free medium, but was induced by salinity or osmotic stress. Application of exogenous abscisic acid (ABA) also induced transcript levels within 1 h in a dose-dependent manner. The Vp1 promoter fused to β-glucuronidase or green fluorescent protein reproduced the endogenous Vp1 expression patterns in transgenic maize plants and also revealed previously unknown expression domains of Vp1. The Vp1 promoter is active in the embryo and aleurone cells of developing seeds and, upon drought stress, was also found in phloem cells of vegetative tissues, including cobs, leaves, and stems. Sequence analysis of the Vp1 promoter identified a potential ABA-responsive complex, consisting of an ACGT-containing ABA response element (ABRE) and a coupling element 1-like motif. Electrophoretic mobility shift assay confirmed that the ABRE and putative coupling element 1 components specifically bound proteins in embryo nuclear protein extracts. Treatment of embryos in hormone-free Murashige and Skoog medium blocked the ABRE-protein interaction, whereas exogenous ABA or mannitol treatment restored this interaction. Our data support a model for a VP1-dependent positive feedback mechanism regulating Vp1 expression during seed maturation.
Cold Nights Impair Leaf Growth and Cell Cycle Progression in Maize through Transcriptional Changes of Cell Cycle Genes
Authors: Rymen Bart , Fiorani Fabio , Kartal Fatma , Vandepoele Klaas , Inzé Dirk , Beemster Gerrit T.S. 
Published: January 2007

AbstractLow temperature inhibits the growth of maize (Zea mays) seedlings and limits yield under field conditions. To study the mechanism of cold-induced growth retardation, we exposed maize B73 seedlings to low night temperature (25°C /4°C, day/night) from germination until the completion of leaf 4 expansion. This treatment resulted in a 20% reduction in final leaf size compared to control conditions (25°C/18°C, day/night). A kinematic analysis of leaf growth rates in control and cold-treated leaves during daytime showed that cold nights affected both cell cycle time (+65%) and cell production (−22%). In contrast, the size of mature epidermal cells was unaffected. To analyze the effect on cell cycle progression at the molecular level, we identified through a bioinformatics approach a set of 43 cell cycle genes and analyzed their expression in proliferating, expanding, and mature cells of leaves exposed to either control or cold nights. This analysis showed that: (1) the majority of cell cycle genes had a consistent proliferation-specific expression pattern; and (2) the increased cell cycle time in the basal meristem of leaves exposed to cold nights was associated with differential expression of cell cycle inhibitors and with the concomitant down-regulation of positive regulators of cell division.
Rice SCAMP1 Defines Clathrin-Coated,trans-Golgi–Located Tubular-Vesicular Structures as an Early Endosome in Tobacco BY-2 Cells
Authors: Lam Sheung Kwan , Siu Ching Lung , Hillmer Stefan , Jang Seonghoe , An Gynheung , Robinson David G. , Jiang Liwen 
Published: January 2007

AbstractWe recently identified multivesicular bodies (MVBs) as prevacuolar compartments (PVCs) in the secretory and endocytic pathways to the lytic vacuole in tobacco (Nicotiana tabacum) BY-2 cells. Secretory carrier membrane proteins (SCAMPs) are post-Golgi, integral membrane proteins mediating endocytosis in animal cells. To define the endocytic pathway in plants, we cloned the rice (Oryza sativa) homolog of animal SCAMP1 and generated transgenic tobacco BY-2 cells expressing yellow fluorescent protein (YFP)–SCAMP1 or SCAMP1-YFP fusions. Confocal immunofluorescence and immunogold electron microscopy studies demonstrated that YFP-SCAMP1 fusions and native SCAMP1 localize to the plasma membrane and mobile structures in the cytoplasm of transgenic BY-2 cells. Drug treatments and confocal immunofluorescence studies demonstrated that the punctate cytosolic organelles labeled by YFP-SCAMP1 or SCAMP1 were distinct from the Golgi apparatus and PVCs. SCAMP1-labeled organelles may represent an early endosome because the internalized endocytic markers FM4-64 and AM4-64 reached these organelles before PVCs. In addition, wortmannin caused the redistribution of SCAMP1 from the early endosomes to PVCs, probably as a result of fusions between the two compartments. Immunogold electron microscopy with high-pressure frozen/freeze-substituted samples identified the SCAMP1-positive organelles as tubular-vesicular structures at the trans-Golgi with clathrin coats. These early endosomal compartments resemble the previously described partially coated reticulum and trans-Golgi network in plant cells.
Theindeterminate gametophyte1Gene of Maize Encodes a LOB Domain Protein Required for Embryo Sac and Leaf Development
Authors: Evans Matthew M.S. 
Published: January 2007

AbstractAngiosperm embryo sac development begins with a phase of free nuclear division followed by cellularization and differentiation of cell types. The indeterminate gametophyte1 (ig1) gene of maize (Zea mays) restricts the proliferative phase of female gametophyte development. ig1 mutant female gametophytes have a prolonged phase of free nuclear divisions leading to a variety of embryo sac abnormalities, including extra egg cells, extra polar nuclei, and extra synergids. Positional cloning of ig1 was performed based on the genome sequence of the orthologous region in rice. ig1 encodes a LATERAL ORGAN BOUNDARIES domain protein with high similarity to ASYMMETRIC LEAVES2 of Arabidopsis thaliana. A second mutant allele of ig1 was identified in a noncomplementation screen using active Mutator transposable element lines. Homozygous ig1 mutants have abnormal leaf morphology as well as abnormal embryo sac development. Affected leaves have disrupted abaxial–adaxial polarity and fail to repress the expression of meristem-specific knotted-like homeobox (knox) genes in leaf primordia, causing a proliferative, stem cell identity to persist in these cells. Despite the superficial similarity of ig1-O leaves and embryo sacs, ectopic knox gene expression cannot be detected in ig1-O embryo sacs.
Initiation of actinorhodin export in Streptomyces coelicolor
Authors: Tahlan Kapil , Ahn Sang Kyun , Sing Anson , Bodnaruk Tetyana D. , Willems Andrew R. , Davidson Alan R. , Nodwell Justin R. 
Published: January 2007

SummaryMany microorganisms produce molecules having antibiotic activity and expel them into the environment, presumably enhancing their ability to compete with their neighbours. Given that these molecules are often toxic to the producer, mechanisms must exist to ensure that the assembly of the export apparatus accompanies or precedes biosynthesis. Streptomyces coelicolor produces the polyketide antibiotic actinorhodin in a multistep pathway involving enzymes encoded by genes that are clustered together. Embedded within the cluster are genes for actinorhodin export, two of which, actR and actA resemble the classic tetR and tetA repressor/efflux pump‐encoding gene pairs that confer resistance to tetracycline. Like TetR, which represses tetA, ActR is a repressor of actA. We have identified several molecules that can relieve repression by ActR. Importantly (S)‐DNPA (an intermediate in the actinorhodin biosynthetic pathway) and kalafungin (a molecule related to the intermediate dihydrokalafungin), are especially potent ActR ligands. This suggests that along with the mature antibiotic(s), intermediates in the biosynthetic pathway might activate expression of the export genes thereby coupling export to biosynthesis. We suggest that this could be a common feature in the production of many bioactive natural products.
Interleukin‐8 and glucose in amniotic fluid, fetal fibronectin in vaginal secretions and preterm labor index based on clinical variables are optimal predictive markers for preterm delivery in patients with intact membranes
Authors: Yoneda Satoshi , Sakai Masatoshi , Sasaki Yasushi , Shiozaki Arihiro , Hidaka Takao , Saito Shigeru 
Published: January 2007

AbstractAim:  Various predictive markers for preterm delivery have been proposed in previous studies. We investigated which marker is most reliable.Methods:  In 126 patients with preterm labor before 32 weeks of gestation and intact membranes, who had regular uterine contractions with cervical changes effaced ≥50%, we evaluated seven markers: interleukin (IL)‐8, glucose, and granulocyte count in amniotic fluid (AF); fetal fibronectin (fFN) in vaginal secretions; IL‐8 in cervical mucus; cervical length; and preterm labor index (PLI) based on clinical variables. The relationships of these variables to the occurrence of preterm delivery before 34 weeks were examined by logistic regression analysis.Results:  Values for AF IL‐8, AF granulocyte count, fFN in vaginal secretions, and PLI were significantly higher, while the value for AF glucose was significantly lower, in patients delivering before 34 weeks than those in patients delivering at or following 34 weeks (P < 0.0001 for all). The most sensitive marker for predicting delivery before 34 weeks was AF IL‐8 (sensitivity, 67.8%). The most specific markers were AF IL‐8 (specificity, 95.5%) and PLI (specificity, 95.5%). By the logistic regression analysis, AF IL‐8, AF glucose, fFN in vaginal secretions and PLI showed independent relationships with delivery before 34 weeks (P = 0.0009, P = 0.0032, P = 0.0131 and P = 0.0038, respectively).Conclusions:  In preterm labor with intact membranes, AF IL‐8, AF glucose, fFN in vaginal secretions and PLI were highly predictive markers for detecting preterm delivery before 34 weeks.
Morbidity and mortality associated with pre‐eclampsia at two tertiary care hospitals in Sri Lanka
Authors: Dissanayake Vajira H. W. , Samarasinghe Harshana D. , Morgan Linda , Jayasekara Rohan W. , Seneviratne Harshalal R. , Pipkin Fiona Broughton 
Published: January 2007

AbstractAim:  To report the occurrence of morbidity and mortality associated with carefully phenotyped pre‐eclampsia in a sample of nulliparous Sinhalese women with strictly defined disease.Methods:  A phenotyping database of 180 nulliparous women with pre‐eclampsia and 180 nulliparous normotensive pregnant women who were recruited for a study into genetics of pre‐eclampsia was analyzed.Results:  Women who developed pre‐eclampsia had significantly higher systolic blood pressure (SBP; P = 0.002) and diastolic blood pressure (DBP; P = 0.002) at booking (at approximately 13 weeks of gestation). 38.3%, 28.3% and 33.3% of women delivered at <34 weeks, at 34–36 weeks, and at term, respectively. 78% required a cesarean section. Complications included SBP ≥ 160 mmHg (75.5%); DBP ≥ 110 mmHg (83.8%); proteinuria ≥3 + (150 mg/dL) in the urine protein heat coagulation test (87%); renal failure requiring dialysis (2%); platelet counts <100 × 109/L (13%); ≥70 U/L in aspartate and/or alanine aminotransaminase (15%); placental abruption (4%); eclampsia (9%); and one maternal death. Maternal complications indicative of severe disease, apart from the incidence of SBP ≥ 160 mmHg and DBP ≥ 110 mmHg, were not significantly different in early and late‐onset pre‐eclampsia; fetal outcome was better with late‐onset disease. 48% of babies were small for gestational age. Only 80 of 135 babies of women with pre‐eclampsia whose condition could be confirmed at 6 weeks post‐partum were alive.Conclusions:  Pre‐eclampsia in Sinhalese women is associated with severe maternal morbidity and fetal morbidity and mortality, suggesting that modification of the Western diagnostic criteria and/or guidelines for medical care may be necessary. There is an urgent need to improve neonatal intensive care services in Sri Lanka.
Role of endocrine and growth factors on the ovarian surface epithelium
Authors: Wong Alice S. T. , Leung Peter C. K. 
Published: January 2007

AbstractEpithelial ovarian cancer is a highly fatal disease for which prevention strategies have been limited; in part because of our poor understanding of the underlying biology of its precursor, the ovarian surface epithelium (OSE). The OSE is a single layer of flat‐to‐cuboidal mesothelial cells that covers the surface of the ovary. Despite its inconspicuous appearance in vivo, it is believed that OSE cells actively participate in the cyclical ovulatory rupture and repair process. The continuous rupture of the OSE at ovulation and the subsequent proliferation to repair the wound renders the cells susceptible to genetic damage and malignant transformation. As the ovary is a rich source of multiple hormones, and normal OSE and ovarian carcinomas secrete and have receptors for hormones, growth factors and cytokines, these factors are strong candidates to regulate normal OSE physiology and the transformation and progression of ovarian cancers. In particular, alterations of hormone/growth factor production and receptor expression are common in ovarian tumors. This review summarizes the current knowledge in the field of endocrinology and its relationship to the biology and pathology of the OSE.
Torsion of the normal ovary and oviduct in a pre‐pubertal girl
Authors: Kamio Masaki , Oki Toshimichi , Inomoto Yukiko , Tsuji Takahiro , Yoshinaga Mitsuhiro , Douchi Tsutomu 
Published: January 2007

AbstractWe encountered a 10‐year‐old prepubertal girl with a normal ovary and oviduct torsion. Hemorrhagic infarction of the ovary and oviduct occurred, and these structures were laparoscopically removed. Torsion of the normal ovary and oviduct in a prepubertal girl is discussed.
Allogeneic and autologous ovarian orthotopic transplantation without a vascular pedicle: Morphological, endocrinologic and natural pregnancy assessment
Authors: Petroianu Andy , Alberti Luiz R. , Vasconcellos Leonardo S. 
Published: January 2007

AbstractBackground:  To assess the natural pregnancy of rabbits submitted to bilateral oophorectomy and orthotopic allogeneic or autologous intact and sliced ovarian transplantation without a vascular pedicle, and to determine the morpho‐functional aspects of the transplanted ovaries.Methods:  Fifty‐six female rabbits were studied. The ovaries were removed and orthotopically transplanted or replaced without vascular anastomoses: Group 1 (n = 8), only laparotomy and laparorrhaphy; Group 2A (n = 8), intact ovaries were transplanted on both sides; Group 2B (n = 8), both ovaries were sliced and orthotopically transplanted; Group 2C (n = 8), an intact ovary was transplanted on one side and a sliced ovary on the other side; Groups 3A–C, the ovaries were reimplanted according to the procedure and subgroups described for Group 2. Three months later, the animals were paired with males for copulation. Estradiol, progesterone, FSH and LH hormone levels were assessed. A histological study was carried out, and the number of pregnancies and litters were also determined. Chi‐squared test compared the number of pregnancies and litters. One‐way anova and the Tukey‐Kramer tests compared the hormonal dosages.Results:  Pregnancies occurred in seven rabbits of Group 1, in 37.5% of rabbits in Groups 2A and 3A, in 50% of groups 2B, 3B and 3C, and in 62.5% of group 2C. Hormone levels and histology confirmed the vitality of all ovaries.Conclusions:  Intact or sliced orthotopic allogeneic and autologous ovarian transplantation without a vascular pedicle is viable in rabbits, and preserves their hormonal and fertile functions.
Folic acid prevents neural tube defects: International comparison of awareness among obstetricians/gynecologists and urologists
Authors: Kondo Atsuo , Kamihira Osamu , Gotoh Momokazu , Ozawa Hideo , Lee Tchun Yong , Lin Alex T‐L. , Kim Seung‐Ryong , Lin Ho‐Hsiung 
Published: January 2007

AbstractAim:  It has been suggested that periconceptional intake of folic acid prevents risks of having fetuses afflicted with neural tube defects. We aim to internationally investigate knowledge of the role of folic acid and attitudes toward the life‐style of young women of child‐bearing age among obstetricians/gynecologists and urologists.Methods:  A questionnaire was sent to obstetricians/gynecologists and urologists residing in Japan, South Korea, Taiwan, North America, Europe, Australia and New Zealand by post or e‐mail. The investigation was conducted between December 2002 and November 2004.Results:  A mean of 91% of obstetricians/gynecologists and 56% of urologists are aware of the role of folic acid, where Asian urologists knew less compared to those of North America, Europe, Australia and New Zealand. A majority of doctors always, or occasionally, recommend folic acid supplements or multivitamins, well‐balanced meals, and the cessation of smoking and drinking. An average of 85% of doctors believes information on folic acid should be disseminated to young women.Conclusions:  A majority of obstetricians/gynecologists and urologists know the importance of periconceptional folic acid in reducing the risk of neural tube defects and have been advising young women to improve their lifestyle.