Publications by authors named "Dominik Schmidt"

33 Publications

Effects of Alzheimer-Like Pathology on Homocysteine and Homocysteic Acid Levels-An Exploratory In Vivo Kinetic Study.

Int J Mol Sci 2021 Jan 18;22(2). Epub 2021 Jan 18.

Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Theodor-Stern-Kai 7, 60596 Frankfurt am Main, Germany.

Hyperhomocysteinemia has been suggested potentially to contribute to a variety of pathologies, such as Alzheimer's disease (AD). While the impact of hyperhomocysteinemia on AD has been investigated extensively, there are scarce data on the effect of AD on hyperhomocysteinemia. The aim of this in vivo study was to investigate the kinetics of homocysteine (HCys) and homocysteic acid (HCA) and effects of AD-like pathology on the endogenous levels. The mice received a B-vitamin deficient diet for eight weeks, followed by the return to a balanced control diet for another eight weeks. Serum, urine, and brain tissues of knock-in and C57BL/6J wild type mice were analyzed for HCys and HCA using LC-MS/MS methods. Hyperhomocysteinemic levels were found in wild type and knock-in mice due to the consumption of the deficient diet for eight weeks, followed by a rapid normalization of the levels after the return to control chow. Hyperhomocysteinemic mice had significantly higher HCys in all matrices, but not HCA, compared to wild type control. Higher serum concentrations were associated with elevated levels in both the brain and in urine. Our findings confirm a significant impact of AD-like pathology on hyperhomocysteinemia in the mouse model. The immediate normalization of HCys and HCA after the supply of B-vitamins strengthens the idea of a B-vitamin intervention as a potentially preventive treatment option for HCys-related disorders such as AD.
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http://dx.doi.org/10.3390/ijms22020927DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7831937PMC
January 2021

Responses on Must and Wine Composition of L. cvs. Riesling and Cabernet Sauvignon under a Free Air CO Enrichment (FACE).

Foods 2021 Jan 12;10(1). Epub 2021 Jan 12.

Department of General and Organic Viticulture, Hochschule Geisenheim University, Von-Lade-Strasse 1, 65366 Geisenheim, Germany.

Challenges of climate change on the future grape and wine production are widely discussed in science and in the wine industry with the goal to maintain a consistent must and wine quality in the future. Therefore, the effect of elevated CO (eCO)-as one of the relevant greenhouse gases jointly responsible for a changing climate-was investigated concerning the composition of must and wine made of two grapevine cultivars L. cvs. Riesling and Cabernet Sauvignon within the established VineyardFACE (Free-Air Carbon dioxide Enrichment) experiment. Must and wine analysis were conducted in three consecutive years (2014-2016) by analyzing standard must and wine parameters, e.g., total soluble solids (TSS), pH, total acidity (TA), organic acids (e.g., tartaric acid, malic acid, shikimic acid, citric acid, volatile acid and gluconic acid) or total phenolics (TP). Also, for both cultivars CIELab coordinates (L* for lightness, a* as green/red and b* as blue/yellow components) were used to test colour in young white and red wines. Additionally, total anthocyanins and monomeric indices were analyzed for young wines of the red cultivar Cabernet Sauvignon. With marginal differences between CO treatments, the composition of must and young wines was not found to be negatively influenced by an eCO concentration.
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http://dx.doi.org/10.3390/foods10010145DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7828110PMC
January 2021

Impact of Hyperhomocysteinemia and Different Dietary Interventions on Cognitive Performance in a Knock-in Mouse Model for Alzheimer's Disease.

Nutrients 2020 Oct 23;12(11). Epub 2020 Oct 23.

Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Branch for Translational Medicine and Pharmacology TMP, Theodor-Stern-Kai 7, 60596 Frankfurt am Main, Germany.

Background: Hyperhomocysteinemia is considered a possible contributor to the complex pathology of Alzheimer's disease (AD). For years, researchers in this field have discussed the apparent detrimental effects of the endogenous amino acid homocysteine in the brain. In this study, the roles of hyperhomocysteinemia driven by vitamin B deficiency, as well as potentially beneficial dietary interventions, were investigated in the novel knock-in mouse model for AD, simulating an early stage of the disease.

Methods: Urine and serum samples were analyzed using a validated LC-MS/MS method and the impact of different experimental diets on cognitive performance was studied in a comprehensive behavioral test battery. Finally, we analyzed brain samples immunohistochemically in order to assess amyloid-β (Aβ) plaque deposition.

Results: Behavioral testing data indicated subtle cognitive deficits in compared to C57BL/6J wild type mice. Elevation of homocysteine and homocysteic acid, as well as counteracting dietary interventions, mostly did not result in significant effects on learning and memory performance, nor in a modified Aβ plaque deposition in 35-week-old mice.

Conclusion: Despite prominent Aβ plaque deposition, the model merely displays a very mild AD-like phenotype at the investigated age. Older mice should be tested in order to further investigate potential effects of hyperhomocysteinemia and dietary interventions.
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http://dx.doi.org/10.3390/nu12113248DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7690745PMC
October 2020

Glucagon-like peptide 2 for intestinal stem cell and Paneth cell repair during graft-versus-host disease in mice and humans.

Blood 2020 09;136(12):1442-1455

Department of Medicine I, Faculty of Medicine, Medical Center University of Freiburg (MCUF).

Acute graft-versus-host disease (GVHD) is a life-threatening complication after allogeneic hematopoietic cell transplantation (allo-HCT). Although currently used GVHD treatment regimens target the donor immune system, we explored here an approach that aims at protecting and regenerating Paneth cells (PCs) and intestinal stem cells (ISCs). Glucagon-like-peptide-2 (GLP-2) is an enteroendocrine tissue hormone produced by intestinal L cells. We observed that acute GVHD reduced intestinal GLP-2 levels in mice and patients developing GVHD. Treatment with the GLP-2 agonist, teduglutide, reduced de novo acute GVHD and steroid-refractory GVHD, without compromising graft-versus-leukemia (GVL) effects in multiple mouse models. Mechanistically GLP-2 substitution promoted regeneration of PCs and ISCs, which enhanced production of antimicrobial peptides and caused microbiome changes. GLP-2 expanded intestinal organoids and reduced expression of apoptosis-related genes. Low numbers of L cells in intestinal biopsies and high serum levels of GLP-2 were associated with a higher incidence of nonrelapse mortality in patients undergoing allo-HCT. Our findings indicate that L cells are a target of GVHD and that GLP-2-based treatment of acute GVHD restores intestinal homeostasis via an increase of ISCs and PCs without impairing GVL effects. Teduglutide could become a novel combination partner for immunosuppressive GVHD therapy to be tested in clinical trials.
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http://dx.doi.org/10.1182/blood.2020005957DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7498363PMC
September 2020

Graft-versus-host disease of the CNS is mediated by TNF upregulation in microglia.

J Clin Invest 2020 03;130(3):1315-1329

Department of Medicine I, Faculty of Medicine, Medical Center.

Acute graft-versus-host disease (GVHD) can affect the central nervous system (CNS). The role of microglia in CNS-GVHD remains undefined. In agreement with microglia activation, we found that profound morphological changes and MHC-II and CD80 upregulation occurred upon GVHD induction. RNA sequencing-based analysis of purified microglia obtained from mice with CNS-GVHD revealed TNF upregulation. Selective TNF gene deletion in microglia of Cx3cr1creER Tnffl/- mice reduced MHC-II expression and decreased CNS T cell infiltrates and VCAM-1+ endothelial cells. GVHD increased microglia TGF-β-activated kinase-1 (TAK1) activation and NF-κB/p38 MAPK signaling. Selective Tak1 deletion in microglia using Cx3cr1creER Tak1fl/fl mice resulted in reduced TNF production and microglial MHC-II and improved neurocognitive activity. Pharmacological TAK1 inhibition reduced TNF production and MHC-II expression by microglia, Th1 and Th17 T cell infiltrates, and VCAM-1+ endothelial cells and improved neurocognitive activity, without blocking graft-versus-leukemia effects. Consistent with these findings in mice, we observed increased activation and TNF production of microglia in the CNS of GVHD patients. In summary, we prove a role for microglia in CNS-GVHD, identify the TAK1/TNF/MHC-II axis as a mediator of CNS-GVHD, and provide a TAK1 inhibitor-based approach against GVHD-induced neurotoxicity.
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http://dx.doi.org/10.1172/JCI130272DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7269577PMC
March 2020

miR-146a Controls Immune Response in the Melanoma Microenvironment.

Cancer Res 2019 01 13;79(1):183-195. Epub 2018 Nov 13.

Department of Hematology, Oncology and Stem Cell Transplantation, Freiburg University Medical Center, Albert-Ludwigs-University Freiburg, Freiburg, Germany.

MicroRNAs (miR) are small noncoding RNAs that regulate gene expression, posttranscription, and manipulate immune responses in different types of cancers. In this study, we identify miR-146a as a negative regulator of immune activation, comparable to immune-checkpoint molecules. miR-146a levels were increased in melanoma microenvironmental tissue, and mice survived longer and developed less metastases in comparison with wild-type melanoma-bearing mice. T cells isolated from mice revealed higher expression levels of the miR-146a target gene Stat1 and the Stat1-regulated cytokine IFNγ. Neutralization of IFNγ in mice decreased survival and increased melanoma metastasis patterns to those of wild-type mice. , IFNγ reduced melanoma cell migration, cell-cycle activity, and basal metabolic rate. Conversely, IFNγ also increased PD-L1 levels on the melanoma cells, which may counterbalance some of the beneficial effects increasing immune escape . Combined treatment with a miR-146a antagomiR and anti-PD-1 resulted in improved survival over isotype control or anti-PD-1 treatment alone. In summary, these data show that miR-146a plays a central role within the STAT1/IFNγ axis in the melanoma microenvironment, affecting melanoma migration, proliferation, and mitochondrial fitness as well as PD-L1 levels. Additionally, combined inhibition of PD-1 and miR-146a could be a novel strategy to enhance antitumor immune response elicited by checkpoint therapy. SIGNIFICANCE: These findings identify a microRNA-based mechanism by which melanoma cells escape the immune system, providing a new therapeutic strategy to improve the current management of patients with melanoma.
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http://dx.doi.org/10.1158/0008-5472.CAN-18-1397DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6330089PMC
January 2019

Oxygen Consumption by Postfermentation Wine Yeast Lees: Factors Affecting Its Rate and Extent under Oenological Conditions.

Food Technol Biotechnol 2016 Dec;54(4):395-402

Modeling and Simulation Group, Hochschule Geisenheim University, von-Lade-Str. 1, 
DE-65366 Geisenheim, Germany.

Postfermentation wine yeast lees show antioxidant properties based on their ability to consume dissolved oxygen. The oxygen consumption capacity of suspended yeast lees obtained after fermentations with six commercial active dry yeast strains was investigated in model, white and red wines using fluorescence-based oxygen sensors operating in a nondestructive way. In model solution, the oxygen consumption rate of yeast lees was shown to depend on their amount, yeast strain, sulfur dioxide and temperature. It is slightly lower in red than in white wines. It is strongly decreased by current levels of free sulfur dioxide, thus excluding the complementary use of both as antioxidants in wine. However, in 25 randomly sampled white wines produced under commercial conditions, the rate and extent of oxygen consumption during the first six months of postfermentation had no significant correlation with any of these interacting factors, making it difficult to predict the actual antioxidant effect of yeast lees. In these wines, yeast lees consumed 0 to 47% of the dissolved oxygen. Although total oxygen consumption capacity of yeast lees is not a limiting factor under commercial winemaking conditions, their oxygen consumption proceeds at a limited rate that reduces but cannot totally prevent concomitant chemical oxidation of the wine.
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http://dx.doi.org/10.17113/ftb.54.04.16.4651DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5253980PMC
December 2016

Sexual function in adult patients with classic bladder exstrophy: A multicenter study.

J Pediatr Urol 2015 Jun 12;11(3):125.e1-6. Epub 2015 Mar 12.

Department of Urology and Pediatric Urology, University of Ulm, Germany. Electronic address:

Background: The bladder exstrophy-epispadias complex (BEEC) comprises a spectrum of congenital anomalies that represents the severe end of urorectal malformations, and has a profound impact on continence as well as sexual and renal functions.

Objective: The relation between severity of BEEC and its associated functional impairments, on one hand, and the resulting restrictions in quality of life and potential psychopathology determine the patients' outcome. It is important for improving further outcome to identify BEEC-related sources of distress in the long term. Genital function and sexuality becomes an important issue for adolescent and adult BEEC individuals. Hence, the present study focused on sexual function and psychological adaption in patients with BEEC.

Study Design: In a multicenter study 52 patients (13 females, 39 males) with classic bladder exstrophy (BE) with their bladders in use were assessed by a self-developed questionnaire about sexual function, and psychosexual and psychosocial outcome. The patients were born between 1948 and 1994 (median age 31 years).

Results: Twelve of 13 (92%) females and 25 of 39 (64%) males with classic BE had answered the questions on sexual function. Of these, 50% females and 92% males answered that they masturbated. Females had sexual intercourse more frequently. Six (50%) females affirmed dyspareunia whereas only two (8%) males reported pain during erection. Eight (67%) females specified having orgasms. Eighteen (72%) males were able to ejaculate. Two males and none of the females lived in a committed partnership (Figure). Two (15%) females and 13 (33%) males answered all psychosocial questions. The majority of these patients had concerns about satisfactory sexuality and lasting, happy partnerships. A minority of patients of both sexes were willing to answer psychosocial questions. Sexual activity and relationships of many adult BE patients seems to be impaired. Not surprisingly, sexual activity and awareness were different in males and females even in a multi-organ anomaly.

Discussion: To date, one of the main goals of the medical treatment of BEEC/BE patients is to enable normal sexual life and fertility. However, only a few outcome studies have focused on these issues with contradicting results, most of them not using standardized outcome measures. In accordance with other studies, our female BE patients have dyspareunia and most of our male BE patients were able to ejaculate. But the question of normal force of ejaculation, ejaculated volume, or semen analysis remains unanswered. Despite partial confirmation of previous findings, there is inconsistency referring to the outcome measured by the available studies. This might in part be explained by the fact that, other than this study, most previous studies are the result of single-institution experience. Thus, selection bias in the patient sampling due to different a clinical collective in different hospitals may be the consequence. Furthermore, patients' honesty and self-reflection in answering difficult questions regarding their sexual and cosmetic impairments is questionable. In addition, studies include a wide range of age groups and are connected with this life period. Fears and condition-specific anxieties might change over time. Hence, the strengths of this study are the nationwide and treating physician-independent data acquisition as well as the large sample size of adult patients with a very rare congenital malformation. Unfortunately, more detailed analyses on sexual function and current psychosocial situation, for example correlation of data with clinical symptoms such as continence status, was not possible as data were mainly not answered by patients.

Conclusion: To improve the quality of life of patients with BEEC/BE, treatment and follow-up should emphasize physical but also psychological care in these patients. Physicians should further re-evaluate their preconceptions and should take care of the patients throughout their lives.
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http://dx.doi.org/10.1016/j.jpurol.2015.02.001DOI Listing
June 2015

Genome-wide mapping of copy number variations in patients with both anorectal malformations and central nervous system abnormalities.

Birth Defects Res A Clin Mol Teratol 2015 Apr 24;103(4):235-42. Epub 2014 Sep 24.

Institute of Human Genetics, University of Bonn, Bonn, Germany.

Background: Anorectal malformations (ARM) have a prevalence of around 1 in 2500 live births. In around 50% of patients, the malformation is isolated, while in the remainder it arises within the context of complex genetic abnormalities or a defined genetic syndrome. Recent studies have implicated rare copy number variations (CNVs) in both isolated and nonisolated ARM, and identified plausible candidate genes.

Methods: In the present study, array-based molecular karyotyping was performed to identify causative CNVs in 32 sporadic ARM patients with comorbid abnormalities of the central nervous system (CNS). This phenotype was selected to enrich for rare CNVs, since previous research has implicated rare CNVs in both CNS abnormalities and ARM.

Results: In five patients, a probable disease-causing CNV was identified (del6q14.3q16.3, del14q32.2, del17q12q21.2, and two patients with del22q11.21). In three of these patients, the CNVs were de novo. For the remaining two patients, no parental DNA was available. Deletions at 22q11.21 and 6q14.3 have been associated with both CNS abnormalities and ARM. In contrast, deletions at 14q32.2 have only been described in patients with CNS abnormalities, and the del17q12q21.2 is a novel CNV. Expression studies in mice suggest that NEUROD2 and RARA, which reside within the newly identified del17q12q21.2 region, are candidate genes for the formation of microcephaly and ARM.

Conclusion: The present data suggest that CNVs are a frequent cause of the ARM with CNS abnormalities phenotype, and that array-analysis is indicated in such patients.
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http://dx.doi.org/10.1002/bdra.23321DOI Listing
April 2015

Heterozygous FGF8 mutations in patients presenting cryptorchidism and multiple VATER/VACTERL features without limb anomalies.

Birth Defects Res A Clin Mol Teratol 2014 Oct 8;100(10):750-9. Epub 2014 Aug 8.

Department of Clinical Chemistry and Clinical Pharmacology, University of Bonn, Bonn, Germany.

Background: The acronym VATER/VACTERL association describes the combination of at least three of the following cardinal features: vertebral defects, anorectal malformations, cardiac defects, tracheoesophageal fistula with or without esophageal atresia, renal malformations, and limb defects. Although fibroblast growth factor-8 (FGF8) mutations have mainly found in patients with Kallmann syndrome, mice with a hypomorphic Fgf8 allele or complete gene invalidation display, aside from gonadotropin-releasing hormone deficiency, parts or even the entire spectrum of human VATER/VACTERL association.

Methods: We performed FGF8 gene analysis in 49 patients with VATER/VACTERL association and 27 patients presenting with a VATER/VACTERL-like phenotype (two cardinal features).

Results: We identified two heterozygous FGF8 mutations in patients displaying either VATER/VACTERL association (p.Gly29_Arg34dup) or a VATER/VACTERL-like phenotype (p.Pro26Leu) without limb anomalies. Whereas the duplication mutation has not been reported before, p.Pro26Leu was once observed in a Kallmann syndrome patient. Both our patients had additional bilateral cryptorchidism, a key phenotypic feature in males with FGF8 associated Kallmann syndrome. Each mutation was paternally inherited. Besides delayed puberty in both and additional unilateral cryptorchidism in one of the fathers, they were otherwise healthy. Serum hormone levels downstream the gonadotropin-releasing hormone in both patients and their fathers were within normal range.

Conclusion: Our results suggest FGF8 mutations to contribute to the formation of the VATER/VACTERL association. Further studies are needed to support this observation.
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http://dx.doi.org/10.1002/bdra.23278DOI Listing
October 2014

Whole-exome resequencing reveals recessive mutations in TRAP1 in individuals with CAKUT and VACTERL association.

Kidney Int 2014 Jun 23;85(6):1310-7. Epub 2013 Oct 23.

1] Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA [2] Howard Hughes Medical Institute, Chevy Chase, Maryland, USA.

Congenital abnormalities of the kidney and urinary tract (CAKUT) account for approximately half of children with chronic kidney disease and they are the most frequent cause of end-stage renal disease in children in the US. However, its genetic etiology remains mostly elusive. VACTERL association is a rare disorder that involves congenital abnormalities in multiple organs including the kidney and urinary tract in up to 60% of the cases. By homozygosity mapping and whole-exome resequencing combined with high-throughput mutation analysis by array-based multiplex PCR and next-generation sequencing, we identified recessive mutations in the gene TNF receptor-associated protein 1 (TRAP1) in two families with isolated CAKUT and three families with VACTERL association. TRAP1 is a heat-shock protein 90-related mitochondrial chaperone possibly involved in antiapoptotic and endoplasmic reticulum stress signaling. Trap1 is expressed in renal epithelia of developing mouse kidney E13.5 and in the kidney of adult rats, most prominently in proximal tubules and in thick medullary ascending limbs of Henle's loop. Thus, we identified mutations in TRAP1 as highly likely causing CAKUT or VACTERL association with CAKUT.
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http://dx.doi.org/10.1038/ki.2013.417DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3997628PMC
June 2014

De novo 13q deletions in two patients with mild anorectal malformations as part of VATER/VACTERL and VATER/VACTERL-like association and analysis of EFNB2 in patients with anorectal malformations.

Am J Med Genet A 2013 Dec 16;161A(12):3035-41. Epub 2013 Aug 16.

Institute of Human Genetics, University of Bonn, Bonn, Germany.

Anorectal malformations (ARMs) comprise a broad spectrum of conditions ranging from mild anal anomalies to complex cloacal malformations. In 40-50% of cases, ARM occurs within the context of defined genetic syndromes or complex multiple congenital anomalies, such as VATER/VACTERL (vertebral defects [V], ARMs [A], cardiac defects [C], tracheoesophageal fistula with or without esophageal atresia [TE], renal malformations [R], and limb defects [L]) association. Here, we report the identification of deletions at chromosome 13q using single nucleotide polymorphism-based array analysis in two patients with mild ARM as part of VATER/VACTERL and VATER/VACTERL-like associations. Both deletions overlap the previously defined critical region for ARM. Heterozygous Efnb2 murine knockout models presenting with mild ARM suggest EFNB2 as an excellent candidate gene in this region. Our patients showed a mild ARM phenotype, closely resembling that of the mouse. We performed a comprehensive mutation analysis of the EFNB2 gene in 331 patients with isolated ARM, or ARM as part of VATER/VACTERL or VATER/VACTERL-like associations. However, we did not identify any disease-causing mutations. Given the convincing argument for EFNB2 as a candidate gene for ARM, analyses of larger samples and screening of functionally relevant non-coding regions of EFNB2 are warranted. In conclusion, our report underlines the association of chromosome 13q deletions with ARM, suggesting that routine molecular diagnostic workup should include the search for these deletions. Despite the negative results of our mutation screening, we still consider EFNB2 an excellent candidate gene for contributing to the development of ARM in humans.
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http://dx.doi.org/10.1002/ajmg.a.36153DOI Listing
December 2013

Isolated bladder exstrophy associated with a de novo 0.9 Mb microduplication on chromosome 19p13.12.

Birth Defects Res A Clin Mol Teratol 2013 Mar 29;97(3):133-9. Epub 2013 Jan 29.

Institute of Human Genetics, University of Bonn, Bonn, Germany.

Background: The exstrophy-epispadias complex (BEEC) is a urogenital birth defect of varying severity. The causes of the BEEC are likely to be heterogeneous, with individual environmental or genetic risk factors still being largely unknown. In this study, we aimed to identify de novo causative copy number variations (CNVs) that contribute to the BEEC.

Methods: Array-based molecular karyotyping was performed to screen 110 individuals with BEEC. Promising CNVs were tested for de novo occurrence by investigating parental DNAs. Genes located in regions of rearrangements were prioritized through expression analysis in mice to be sequenced in the complete cohort, to identify high-penetrance mutations involving small sequence changes.

Results: A de novo 0.9 Mb microduplication involving chromosomal region 19p13.12 was identified in a single patient. This region harbors 20 validated RefSeq genes, and in situ hybridization data showed specific expression of the Wiz gene in regions surrounding the cloaca and the rectum between GD 9.5 and 13.5. Sanger sequencing of the complete cohort did not reveal any pathogenic alterations affecting the coding region of WIZ.

Conclusions: The present study suggests chromosomal region 19p13.12 as possibly involved in the development of CBE, but further studies are needed to prove a causal relation. The spatiotemporal expression patterns determined for the genes encompassed suggest a role for Wiz in the development of the phenotype. Our mutation screening, however, could not confirm that WIZ mutations are a frequent cause of CBE, although rare mutations might be detectable in larger patient samples. 19p13.12, microduplication, bladder exstrophy-epispadias complex, array-based molecular karyotyping, in situ hybridization analysis, copy number variations, WIZ gene.
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http://dx.doi.org/10.1002/bdra.23112DOI Listing
March 2013

Assisted reproductive techniques and risk of exstrophy-epispadias complex: a German case-control study.

J Urol 2013 Apr 27;189(4):1524-9. Epub 2012 Nov 27.

Division of Clinical Epidemiology and Aging Research, German Cancer Research Center, Heidelberg, Germany.

Purpose: We assessed the risk of exstrophy-epispadias complex in children conceived by in vitro fertilization or intracytoplasmic sperm injection.

Materials And Methods: Data from the German Network for Congenital Uro-REctal malformations were compared to nationwide data from the German In Vitro Fertilization Register and the German Federal Statistical Office. Odds ratios (95% CI) were determined to quantify associations using logistic regression.

Results: A total of 123 patients with exstrophy-epispadias complex born in Germany between 1997 and 2011 were recruited through participating departments of pediatric urology and pediatric surgery throughout the country as well as the German self-help organizations Blasenekstrophie/Epispadie e.V. and Kloakenekstrophie. All German live births (10,069,986) between 1997 and 2010 comprised the controls. Overall, 12 subjects (10%) and 129,982 controls (1%) were conceived by in vitro fertilization or intracytoplasmic sperm injection. Conception by assisted reproductive technique was associated with a more than eightfold increased risk of exstrophy-epispadias complex compared to spontaneous conception (OR 8.3, 95% CI 4.6-15.0, p <0.001). Separate analyses showed a significantly increased risk of exstrophy-epispadias complex in children conceived by in vitro fertilization (OR 14.0, 95% CI 6.5-30.0, p <0.0001) or intracytoplasmic sperm injection (OR 5.3, 95% CI 2.2-12.9, p <0.0001).

Conclusions: This study provides evidence that assisted reproductive techniques such as in vitro fertilization and intracytoplasmic sperm injection are associated with a markedly increased risk of having a child born with exstrophy-epispadias complex. However, it remains unclear whether this finding may be due to assisted reproduction per se and/or underlying infertility/subfertility etiology or parent characteristics.
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http://dx.doi.org/10.1016/j.juro.2012.11.108DOI Listing
April 2013

Assisted reproductive techniques and the risk of anorectal malformations: a German case-control study.

Orphanet J Rare Dis 2012 Sep 15;7:65. Epub 2012 Sep 15.

Division of Clinical Epidemiology and Aging Research, German Cancer Research Center, Heidelberg, Germany.

Background: The use of assisted reproductive techniques (ART) for treatment of infertility is increasing rapidly worldwide. However, various health effects have been reported including a higher risk of congenital malformations. Therefore, we assessed the risk of anorectal malformations (ARM) after in-vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI).

Methods: Data of the German Network for Congenital Uro-REctal malformations (CURE-Net) were compared to nationwide data of the German IVF register and the Federal Statistical Office (DESTATIS). Odds ratios (95% confidence intervals) were determined to quantify associations using multivariable logistic regression accounting for potential confounding or interaction by plurality of births.

Results: In total, 295 ARM patients born between 1997 and 2011 in Germany, who were recruited through participating pediatric surgeries from all over Germany and the German self-help organisation SoMA, were included. Controls were all German live-births (n = 10,069,986) born between 1997 and 2010. Overall, 30 cases (10%) and 129,982 controls (1%) were born after IVF or ICSI, which translates to an odds ratio (95% confidence interval) of 8.7 (5.9-12.6) between ART and ARM in bivariate analyses. Separate analyses showed a significantly increased risk for ARM after IVF (OR, 10.9; 95% CI, 6.2-19.0; P < 0.0001) as well as after ICSI (OR, 7.5; 95% CI, 4.6-12.2; P < 0.0001). Furthermore, separate analyses of patients with isolated ARM, ARM with associated anomalies and those with a VATER/VACTERL association showed strong associations with ART (ORs 4.9, 11.9 and 7.9, respectively). After stratification for plurality of birth, the corresponding odds ratios (95% confidence intervals) were 7.7 (4.6-12.7) for singletons and 4.9 (2.4-10.1) for multiple births.

Conclusions: There is a strongly increased risk for ARM among children born after ART. Elevations of risk were seen after both IVF and ICSI. Further, separate analyses of patients with isolated ARM, ARM with associated anomalies and those with a VATER/VACTERL association showed increased risks in each group. An increased risk of ARM was also seen among both singletons and multiple births.
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http://dx.doi.org/10.1186/1750-1172-7-65DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3519554PMC
September 2012

Involvement of the WNT and FGF signaling pathways in non-isolated anorectal malformations: sequencing analysis of WNT3A, WNT5A, WNT11, DACT1, FGF10, FGFR2 and the T gene.

Int J Mol Med 2012 Dec 7;30(6):1459-64. Epub 2012 Sep 7.

Institute of Human Genetics, University Hospital of Bonn, D-53127 Bonn, Germany.

Anorectal malformations (ARMs) comprise a broad spectrum of anomalies, including anal atresia, congenital anal fistula and persistence of the cloaca. Research suggests that genetic factors play an important role in ARM development. However, few genetic variants have been identified. Embryogenesis is orchestrated by crosstalk of the wingless-type MMTV integration site family (WNT) and fibroblast growth factor (FGF) signaling pathways in a process that involves several intracellular cascades. Studies in mice have implicated several genes from these pathways in the etiology of ARMs. We performed sequencing analysis of seven of these previously reported genes in 78 patients with ARMs occurring within the context of at least one additional congenital anomaly. No associations were identified with variants in WNT3A, WNT5A, WNT11, DACT1, FGF10 or the T gene. In the FGFR2 gene, three novel heterozygous nucleotide substitutions were identified. Further investigations, including the study of family members, revealed that these variants were not causally related to the phenotype in the present ARM cohort. Mutations in the seven investigated genes may nonetheless be a cause of ARMs in rare cases. However, further studies should consider genes encoding other proteins in the WNT/FGF signaling pathways as possible candidates.
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http://dx.doi.org/10.3892/ijmm.2012.1124DOI Listing
December 2012

Unexpected results of a nationwide, treatment-independent assessment of fecal incontinence in patients with anorectal anomalies.

Pediatr Surg Int 2012 Aug;28(8):825-30

Department of Pediatric Surgery and Urology, Centre for Child and Youth Health, Klinikum Bremen-Mitte, Bremen, Germany.

Purpose: To determine the anorectal function in patients with anorectal malformations (ARM) in order to facilitate patient counseling and follow-up.

Methods: Data were collected by the German network for urorectal malformations (CURE-Net) according to the International Krickenbeck consensus. Questionnaires on bowel function and a defecation protocol were completed by the families/patients. The clinical findings were assessed from the patients' clinical records.

Results: Two hundred and ninety-seven patients with ARM were assessed, 175 patients gave complete data on continence, 52 of them were excluded due to mental retardation, age, and earlier type of pullthrough. Complete continence was found in 27 %, perineal fistula in 40 %, rectourethral/vesical in 10 %, vestibular in 24 %, cloaca in 0 %. Krickenbeck grade 1 soiling: 42 %, grade 2 and 3: 31 %. Forty-nine percent of the incontinent patients practiced bowel management, reaching continence in 19 %. The statement of constipation (67 %) was validated with the last clinical findings, showing coprostasis in 46 %, "Not suffering constipation" was confirmed in 61 % and falsified in 29 %.

Conclusion: ARM patients in Germany, as assessed by independent researchers, show a high rate of fecal incontinence and insufficiently treated constipation. Parents should be counseled accordingly and motivated to engage in consequent follow-up. Intensified efforts in the conservative treatment of constipation and fecal incontinence are crucial to improvement.
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http://dx.doi.org/10.1007/s00383-012-3127-1DOI Listing
August 2012

Sexual function in adults with anorectal malformation: psychosocial adaptation. German Network for Congenital Uro-REctal Malformations (CURE-Net).

Pediatr Surg Int 2012 Aug;28(8):789-92

Department of Pediatric Surgery, Charité Universitätsmedizin Berlin, Berlin, Germany.

Purpose: The aim of the German Network for Congenital Uro-REctal Malformations (CURE-Net) is to collect data of affected patients with anorectal malformation (ARM) to investigate molecular causes, clinical implications and psychosocial outcome. The current issue was to examine sexual function and to explore psychosocial adaptation in adults with ARM.

Methods: This qualitative study using narrative inquiry is part of a larger multi-center study of clinical queries and quality of life in patients with ARM. The guided interview focused on analysis of sexual function.

Results: 55 adult patients with ARM (23 females, 32 males, median age 23 years, range from 18 to 56 years) were investigated via standardized case-report forms comprising interview, analysis of medical data and personal questionnaires. In the female patients, 8 (35 %) of them lived alone and 15 (65 %) had sexual intercourse. In the male patients, the majority of 20 (69 %) patients lived alone and 13 (45 %) had sexual intercourse. 6 of the females got pregnant, 5 got 2 or more children. 3 of the men induced 2 or more pregnancies and fathered children.

Conclusion: Besides reconstructing the ARM, another main goal is the preservation of sexual function. According to our data, there seems to be a close relationship between psychosocial development and sexual activity.
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http://dx.doi.org/10.1007/s00383-012-3119-1DOI Listing
August 2012

[Use of operationalized psychodynamic diagnostics in childhood and adolescence in patients with somatic diseases].

Psychother Psychosom Med Psychol 2012 Jul 9;62(7):259-65. Epub 2012 Jul 9.

Klinik für Psychiatrie, Psychosomatik und Psychotherapie des Kindes- und Jugendalters, Charité Universitätsmedizin Berlin.

Psychodynamic findings based on the Operationalized Psychodynamic Diagnostics in Childhood and Adolescence (OPD-CA) in patients with Anorectal Malformations (ARM) in comparison to psychiatric patients were presented focussing the psychic structure. Patients with ARM had significant better psychic structure especially with regard to coping with conflicts and communication of affects. Furthermore typical findings were generated: Patients with ARM had better treatment conditions and more positive relationships. Still they had fewer hypotheses about their disease and greater living burden. Structural strengthes facilitate acceptance and integration of the disease. Nonetheless more attention should be paid to child-oriented psychoeducation for development of age-appropriate hypotheses about the disease. Facing living burden, psychological-psychiatric support should be offered to patients with ARM.
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http://dx.doi.org/10.1055/s-0032-1314784DOI Listing
July 2012

Postoperative complications in adults with anorectal malformation: a need for transition. German Network for Congenital Uro-REctal Malformations (CURE-Net).

Pediatr Surg Int 2012 Aug;28(8):793-5

Department of Pediatric Surgery, Charité Universitätsmedizin Berlin, Berlin, Germany.

Purpose: The aim of the German Network for Congenital Uro-REctal malformations (CURE-Net) is to collect data of affected patients with anorectal malformation (ARM) to investigate molecular causes, clinical implications and psychosocial outcome. The current issue was to examine the transition to adulthood in adults with ARM and to explore condition-related needs and skills required.

Methods: This qualitative study is part of a larger multi-center study of clinical queries and quality of life in patients with ARM. The guided interview focused on the analysis of medical data and personal questionnaires.

Results: Interviews were completed with 55 (23 females, 32 males) participants, age ranging from 18 to 56 years. Twenty-one patients suffered from mucosal prolapse, 18 patients had had megasigmoid/megacolon. Relevant stenosis of the neo-anus occurred in 13 (42 %) males and 4 (18 %) females, permanent neurogenic bladder dysfunction in 10 (32 %) males and 4 (18 %) females, recurrent urinary tract infections in 10 (32 %) males and 13 (59 %) females, latex allergy in 10 (32 %) males and 7 (32 %) females. Thirty-seven (70 %) patients had to be reoperated. Forty-one (75 %) patients needed means of aftercare to achieve social continence.

Conclusion: The study wants to contribute to a better understanding of the challenges of transition for adults with ARM.
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http://dx.doi.org/10.1007/s00383-012-3120-8DOI Listing
August 2012

Inheritance of the VATER/VACTERL association.

Pediatr Surg Int 2012 Jul 12;28(7):681-5. Epub 2012 May 12.

Institute of Human Genetics, University of Bonn, Bonn, Germany.

VATER/VACTERL association refers to the non-random co-occurrence of the following component features: vertebral defects, anal atresia, cardiac malformations, tracheoesophageal atresia, renal abnormalities, and limb defects. Recently, Solomon et al. (Hum Genet 127:731-733, 2010) observed an increased prevalence of component features among first-degree relatives of VATER/VACTERL patients suggesting that in some patients, the disorder may be inherited. To replicate these findings, we investigated 87 VATER/VACTERL patients with the presence of a minimum of three component features and their first-degree relatives (n = 271). No increase in the overall prevalence of component features was observed in first-degree relatives compared to the general population (χ² = 2.68, p = 0.10). Separate analysis for the prevalence of single component features showed a higher prevalence of tracheoesophageal fistula/atresia among first-degree relatives compared to the general population (OR 17.65, 95% CI 2.47-126.05). However, this was based on occurrence in one family only. Our findings suggest that although familial occurrence renders a genetic contribution likely, the overall risk of recurrence among the first-degree relatives of patients with VATER/VACTERL association is probably very low. Since the patients in the present study were young and no offspring could be studied, estimation of the role of de novo mutations in the development of VATER/VACTERL was not possible.
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http://dx.doi.org/10.1007/s00383-012-3100-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4126839PMC
July 2012

German network for congenital uro-rectal malformations: first evaluation and interpretation of postoperative urological complications in anorectal malformations.

Pediatr Surg Int 2011 Oct;27(10):1085-9

Department of Pediatric Surgery, Charité Universitätsmedizin Berlin, Berlin, Germany.

Objective: The aim of the German Network for Congenital Uro-REctal Malformations is to collect data of affected patients with anorectal malformation (ARM) or extrophy-epispadias complex, and to investigate molecular causes, clinical implications, and psychosocial outcome. The current issue was to assess the postoperative sequelae related to lower urinary tract dysfunction in patients with ARM.

Materials And Methods: Two hundred and sixty-seven patients with ARM (112 females, 155 males, median age 6 years, range 0-56 years) were investigated via standardized case report forms comprising interview, analysis of medical data, and personal questionnaires.

Results: Thirty-two patients (12%, 23 males, 9 females) suffered from neurogenic bladder dysfunction, mainly associated with recto-urethral fistula (11 cases, 34%), and recto-vesical fistula (6 cases, 19%). Sixty-eight patients (26%, 35 males, 57 females) have experienced lifetime urinary tract infection, primarily associated with recto-urethral fistula (21 cases, 31%), and vestibular fistula (13 cases, 19%). According to type of operation, the highest number of postoperative urologic problems was reported after abdominosacroperineal pull-through.

Conclusion: Besides reconstructing the ARM, another main goal is the preservation of lower urinary tract function. In our data, there seems to be a close correlation between operative strategies and postoperative complications.
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http://dx.doi.org/10.1007/s00383-011-2951-zDOI Listing
October 2011

Medical predictors of psychological anxieties in VATER patients.

Pediatr Surg Int 2011 Oct;27(10):1079-83

Department of Pediatrics, Pediatric Psychology, University of Bonn, Adenauerallee 119, 53113, Bonn, Germany.

Background/purpose: Following a recent classification of the VATER Association provided by the CURE-Net consortium (submitted), we investigate medical predictors of psychological stress and anxieties in this particular condition.

Methods: We developed a new set of questionnaires measuring psychological adjustment and quality of life outcome in conditions associated with anorectal and/or urogenital malformation (one self- report form to be completed by patients 7-17 years of age, two parent report forms with one relating to patients with an age range of 0-6 years, resp. 7-17 years of age). The questionnaire "Malformation-related Stress and Anxieties" comprises 26 items belonging to five subscales (I. Functional and cosmetic impairment, II. Intimacy and relationship, III. Social inclusion, IV. Psychological functioning, V. Family functioning). Every item can be responded to with respect to both actual, present problems already experienced as well as to future anxieties anticipating future development and adjustment (a perspective which especially applies in younger patients). Internal consistencies of the scales are good, resp. very good (Cronbach's α = .85 concerning present sources of anxiety scale, resp., .94 concerning future anxieties scale). The items are supplied with a Likert-type 5-point scale. We administered the questionnaire in N = 17 children and adolescents suffering from VATER via parental (proxy) report.

Results: As most medical risk factors affected nearly the entire sample, statistical analysis excluded investigation of differential impact on psychological stress experience and anxieties in subjects exposed versus not exposed. Special attention, therefore, was paid to those medical parameters with the best statistical power to differentiate between individuals of high versus low psychological outcome. Medical predictors differentiating between individuals with high versus low adjustment comprise post-operative infections of the urinary tract (t[15] = -3.78, p = .09), wound infections (t[15] = -3.04, p < .01), stoma complications (t[15] = -2.11, p = .08) (e.g., prolapsed (t[13] = -2.37, p = .05), other treatment complications (t[15] = -2.59, p < .05) and presence of a megacolon (t[13] = -2.44, p = .06).

Discussion And Conclusions: From the perspective of stress psychology, the findings may indicate that particular medical characteristics of a malformation may operate via two different pathways: (a) pathway of severity of a particular medical risk factor: the presence of a megacolon, for example, may restrict quality of life and successful adjustment via multiple and long term functional impairments associated and (b) pathway of subjective predictability and controllability of treatment course. In accordance with theoretical models from stress psychology, the psychological impact of complicating factors such as wound-healing infections is not operating via severity of impairment, but via implicit messages they convey, indicating a low predictability and controllability of course of disease and treatment. As a result, they may increase intensity of worry and anxieties upon further difficulties still to come during future development. As a conclusion, psychological counseling may not only address concrete functional impairments and stressors, but also basic feelings of insecurity, controllability and self-efficacy.
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http://dx.doi.org/10.1007/s00383-011-2953-xDOI Listing
October 2011

Regulation of jasmonate metabolism and activation of systemic signaling in Solanum nigrum: COI1 and JAR4 play overlapping yet distinct roles.

New Phytol 2011 May 1;190(3):640-52. Epub 2011 Feb 1.

Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Jena, Germany.

• Jasmonates are ubiquitous messengers in land plants essential for the activation of defense responses. However, their signaling properties, accumulation and metabolism vary substantially among species. Solanum nigrum is a wild Solanaceous species developed as a model to study defense responses. • Solanum nigrum plants transformed to silence the expression of key genes in jasmonate production (SnLOX3), conjugation (SnJAR4) and perception (SnCOI1) were generated to analyze the function of these genes in jasmonate accumulation and metabolism (studied by a combination of LC-MS/MS and (13) C-isotope labeling methods) and in signaling [studied by the systemic elicitation of leucine aminopeptidase (LAP) activity]. • In contrast with the early single jasmonic acid (JA) burst induced by wounding in wild-type (WT) plants, elicitation with insect oral secretions induced a later, second burst that was essential for the induction of systemic LAP activity, as demonstrated by ablation experiments. This induction was dependent on SnLOX3 and SnCOI1, but not on SnJAR4. In addition, the local accumulation of JA-glucose and JA-isoleucine was dependent on SnCOI1, whereas the accumulation of hydroxylated jasmonates was dependent on both SnCOI1 and SnJAR4. • The results demonstrate that SnLOX3, SnCOI1 and SnJAR4 have overlapping yet distinct roles in jasmonate signaling, differentially controlling jasmonate metabolism and the production of a systemic signal.
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http://dx.doi.org/10.1111/j.1469-8137.2010.03622.xDOI Listing
May 2011

[Comorbidity and psychosocial need in children and adolescents with anorectal malformations].

Prax Kinderpsychol Kinderpsychiatr 2010 ;59(1):38-51

Charité Universitätsmedizin Berlin, Klinik für Psychiatrie, Psychosomatik und Psychotherapie des Kindes und Jugendalters, Berlin.

Anorectal malformations (ARM) are not externally visible and have an uncertain medical course. Only about half of the patients with ARM have satisfactory bowel functions. Studies of ARM have reported reduced quality of life and psychosocial problems in up to 73% of the patients. The aim of the current study was to document the psychiatric comorbidity and the psychosocial need of patients with ARM in a multidimensional diagnostic for the first time. The screening sample (N = 30) included 23 male and 7 female patients aged 4-17 years. The introduced Comprehensive Grading System with a sophisticated perspective of continence and associated problems showed 23 patients suffering severe burden. 70 % of the families confirmed increased psychosocial need. In the diagnostic one third of the patients had psychiatric diagnoses, one third had mild problems and one third had no difficulties. Therefore, a group program should be offered to all patients. To the patients with severe forms of ARM or with increased psychosocial need, the multidimensional diagnostic program including advices and recommendations should be offered. Psychosocial assistance is important to reinforce acceptance and integration of coping with the illness in one's life. Early intervention can prevent psychiatric disorders later in life.
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http://dx.doi.org/10.13109/prkk.2010.59.1.38DOI Listing
April 2010

The structure of the culturable root bacterial endophyte community of Nicotiana attenuata is organized by soil composition and host plant ethylene production and perception.

New Phytol 2010 Jan 10;185(2):554-67. Epub 2009 Nov 10.

Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, 07745 Jena, Germany.

*A plant's bacterial endophyte community is thought to be recruited from the rhizosphere, but how this recruitment is influenced by the plant's phytohormone signaling is unknown. Ethylene regulates plant-microbe interactions; here, we assess the role of ethylene in the recruitment of culturable endophytic bacteria from native soils. *We grew wild-type Nicotiana attenuata plants and isogenic transformed plants deficient in ethylene biosynthesis (ir-aco1) or perception (35S-etr1) in four native soils and quantified the extent of culturable bacterial endophyte colonization (by plate counting) and diversity (by amplified rDNA restriction analysis and 16S rDNA sequencing). *The endophyte community composition was influenced by soil type and ethylene signaling. Plants grown in organic (vs mineral) soils harbored a more diverse community and plants impaired in ethylene homeostasis harbored a less diverse community than wild-type plants. Wild-type and ethylene signaling-impaired plants fostered distinct bacteria in addition to common ones. In vitro re-colonization by common and genotype-specific isolates demonstrated the specificity of some associations and the susceptibility of 35S-etr1 seedlings to all tested bacterial isolates, suggesting an active process of colonization driven by plant- and microbe-specific genes. *We propose that soil composition and ethylene homeostasis play central roles in structuring the bacterial endophyte community in N. attenuata roots.
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http://dx.doi.org/10.1111/j.1469-8137.2009.03079.xDOI Listing
January 2010

Arabidopsis plant homeodomain finger proteins operate downstream of auxin accumulation in specifying the vasculature and primary root meristem.

Plant J 2009 Aug 24;59(3):426-36. Epub 2009 Mar 24.

John Innes Centre, Norwich Research Park, Norwich, UK.

In Arabidopsis thaliana, auxin is a key regulator of tissue patterning in the developing embryo. We have identified a group of proteins that act downstream of auxin accumulation in auxin-mediated root and vascular development in the embryo. Combined mutations in OBERON1 (OBE1) and OBERON2 (OBE2) give rise to obe1 obe2 double mutant seedlings that closely phenocopy the monopteros (mp) mutant phenotype, with an absence of roots and defective development of the vasculature. We show that, in contrast to the situation in mp mutants, obe1 obe2 double mutant embryos show auxin maxima at the root pole and in the provascular region, and that the SCF(TIR1) pathway, which translates auxin accumulation into transcriptional activation of auxin-responsive genes, remains intact. Although we focus on the impact of obe mutations on aspects of embryo development, the effect of such mutations on a broad range of auxin-related gene expression and the tissue expression patterns of OBE genes in seedlings suggest that OBE proteins have a wider role to play in growth and development. We suggest that OBE1 and OBE2 most likely control the transcription of genes required for auxin responses through the action of their PHD finger domains.
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http://dx.doi.org/10.1111/j.1365-313X.2009.03874.xDOI Listing
August 2009

Optimized virus-induced gene silencing in Solanum nigrum reveals the defensive function of leucine aminopeptidase against herbivores and the shortcomings of empty vector controls.

New Phytol 2008 Jul;179(2):356-65

Max Planck Institute for Chemical Ecology, Department of Molecular Ecology, Hans-KnölI-Strasse 8, D-07745 Jena, Germany.

Virus-induced gene silencing (VIGS) enables high-throughput analysis of gene function in plants but is not universally applicable and requires optimization for each species. Here a VIGS system is described for Solanum nigrum, a wild relative of tomato and potato and a valuable model species for ecogenomics. The efficiency of the two most widely used Tobacco rattle virus (TRV) vectors to silence phytoene desaturase (PDS) in S. nigrum was tested. Additionally, the infiltration method and growth temperatures for gene silencing were optimized and the suitability of different control vectors evaluated. Using leucine aminopeptidase (LAP), a herbivore-induced protein, silencing efficiency and the applicability of silenced plants for herbivore feeding assays were assessed. Vacuum infiltration of seedlings with Agrobacterium carrying the vector, pYL156, proved the most efficient means of silencing genes. Empty-vector controls decreased plant growth but control vectors carrying a piece of noncoding sequence did not. Silencing LAP significantly increased the larval mass of Manduca sexta that fed on silenced plants. This VIGS protocol proved highly successful for S. nigrum, which should include control vectors carrying noncoding sequence as control treatments. Silencing LAP provided the first experimental evidence that LAP has a defensive function against herbivores.
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http://dx.doi.org/10.1111/j.1469-8137.2008.02479.xDOI Listing
July 2008

Native bacterial endophytes promote host growth in a species-specific manner; phytohormone manipulations do not result in common growth responses.

PLoS One 2008 Jul 16;3(7):e2702. Epub 2008 Jul 16.

Max Planck Institute for Chemical Ecology, Jena, Germany.

Background: All plants in nature harbor a diverse community of endophytic bacteria which can positively affect host plant growth. Changes in plant growth frequently reflect alterations in phytohormone homoeostasis by plant-growth-promoting (PGP) rhizobacteria which can decrease ethylene (ET) levels enzymatically by 1-aminocyclopropane-1-carboxylate (ACC) deaminase or produce indole acetic acid (IAA). Whether these common PGP mechanisms work similarly for different plant species has not been rigorously tested.

Methodology/principal Findings: We isolated bacterial endophytes from field-grown Solanum nigrum; characterized PGP traits (ACC deaminase activity, IAA production, phosphate solubilization and seedling colonization); and determined their effects on their host, S. nigrum, as well as on another Solanaceous native plant, Nicotiana attenuata. In S. nigrum, a majority of isolates that promoted root growth were associated with ACC deaminase activity and IAA production. However, in N. attenuata, IAA but not ACC deaminase activity was associated with root growth. Inoculating N. attenuata and S. nigrum with known PGP bacteria from a culture collection (DSMZ) reinforced the conclusion that the PGP effects are not highly conserved.

Conclusions/significance: We conclude that natural endophytic bacteria with PGP traits do not have general and predictable effects on the growth and fitness of all host plants, although the underlying mechanisms are conserved.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0002702PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2444036PMC
July 2008

SERRATE: a new player on the plant microRNA scene.

EMBO Rep 2006 Oct 15;7(10):1052-8. Epub 2006 Sep 15.

Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, UK.

MicroRNAs (miRNAs) function as sequence-specific guides that control gene expression by post-transcriptional gene silencing. Many miRNAs influence plant development by regulating the accumulation of transcripts that encode transcription factors. Mutants defective in miRNA accumulation, such as dcl1, hen1, hyl1 and ago1, have pleiotropic developmental phenotypes. The serrate-1 (se-1) mutant of Arabidopsis also shows a highly pleiotropic phenotype, which overlaps with the phenotypes of mutants defective in miRNA accumulation. Although it has been proposed that SERRATE (SE) functions specifically in miRNA-mediated repression of the leaf polarity genes PHABULOSA and PHAVOLUTA, microarray analysis shows upregulation of many genes known to be the targets of miRNAs in se-1. We show that SE is a general regulator of miRNA levels affecting the processing of primary miRNA to miRNA.
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http://dx.doi.org/10.1038/sj.embor.7400806DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1618363PMC
October 2006