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971.
M. Carey Satterfield Kathrin A. Dunlap Duane H. Keisler Fuller W. Bazer Guoyao Wu 《Amino acids》2013,45(3):489-499
Intrauterine growth restriction is a significant problem worldwide, resulting in increased rates of neonatal morbidity and mortality, as well as increased risks for metabolic and cardiovascular disease. The present study investigated the role of maternal undernutrition and l-arginine administration on fetal growth and development. Embryo transfer was utilized to generate genetically similar singleton pregnancies. On Day 35 of gestation, ewes were assigned to receive either 50 or 100% of their nutritional requirements. Ewes received i.v. injections of either saline or l-arginine three times daily from Day 100 to Day 125. Fetal growth was assessed at necropsy on Day 125. Maternal dietary manipulation altered circulating concentrations of leptin, progesterone, and amino acids in maternal plasma. Fetal weight was reduced in nutrient-restricted ewes on Day 125 compared with 100% fed ewes. Compared with saline-treated underfed ewes, maternal l-arginine administration did not affect fetal weight but increased weight of the fetal pancreas by 32% and fetal peri-renal brown adipose tissue mass by 48%. These results indicate that l-arginine administration enhanced fetal pancreatic and brown adipose tissue development. The postnatal effects of increased pancreatic and brown adipose tissue growth warrant further study. 相似文献
972.
The Cyanobacterial Role in the Resistance of Feather Mosses to Decomposition—Toward a New Hypothesis
Cyanobacteria-plant symbioses play an important role in many ecosystems due to the fixation of atmospheric nitrogen (N) by the cyanobacterial symbiont. The ubiquitous feather moss Pleurozium schreberi (Brid.) Mitt. is colonized by cyanobacteria in boreal systems with low N deposition. Here, cyanobacteria fix substantial amounts of N2 and represent a potential N source. The feather moss appears to be resistant to decomposition, which could be partly a result of toxins produced by cyanobacteria. To assess how cyanobacteria modulated the toxicity of moss, we measured inhibition of bacterial growth. Moss with varying numbers of cyanobacteria was added to soil bacteria to test the inhibition of their growth using the thymidine incorporation technique. Moss could universally inhibit bacterial growth, but moss toxicity did not increase with N2 fixation rates (numbers of cyanobacteria). Instead, we see evidence for a negative relationship between moss toxicity to bacteria and N2 fixation, which could be related to the ecological mechanisms that govern the cyanobacteria – moss relationship. We conclude that cyanobacteria associated with moss do not contribute to the resistance to decomposition of moss, and from our results emerges the question as to what type of relationship the moss and cyanobacteria share. 相似文献
973.
Peter Reinhardt Michael Glatza Kathrin Hemmer Yaroslav Tsytsyura Cora S. Thiel Susanne H?ing S?ren Moritz Juan A. Parga Lydia Wagner Jan M. Bruder Guangming Wu Benjamin Schmid Albrecht R?pke Jürgen Klingauf Jens C. Schwamborn Thomas Gasser Hans R. Sch?ler Jared Sterneckert 《PloS one》2013,8(3)
Phenotypic drug discovery requires billions of cells for high-throughput screening (HTS) campaigns. Because up to several million different small molecules will be tested in a single HTS campaign, even small variability within the cell populations for screening could easily invalidate an entire campaign. Neurodegenerative assays are particularly challenging because neurons are post-mitotic and cannot be expanded for implementation in HTS. Therefore, HTS for neuroprotective compounds requires a cell type that is robustly expandable and able to differentiate into all of the neuronal subtypes involved in disease pathogenesis. Here, we report the derivation and propagation using only small molecules of human neural progenitor cells (small molecule neural precursor cells; smNPCs). smNPCs are robust, exhibit immortal expansion, and do not require cumbersome manual culture and selection steps. We demonstrate that smNPCs have the potential to clonally and efficiently differentiate into neural tube lineages, including motor neurons (MNs) and midbrain dopaminergic neurons (mDANs) as well as neural crest lineages, including peripheral neurons and mesenchymal cells. These properties are so far only matched by pluripotent stem cells. Finally, to demonstrate the usefulness of smNPCs we show that mDANs differentiated from smNPCs with LRRK2 G2019S are more susceptible to apoptosis in the presence of oxidative stress compared to wild-type. Therefore, smNPCs are a powerful biological tool with properties that are optimal for large-scale disease modeling, phenotypic screening, and studies of early human development. 相似文献
974.
Jennifer K. Bender Thorsten Wille Kathrin Blank Anna Lange Roman G. Gerlach Junior Research Group 《PloS one》2013,8(8)
The larvae of the wax moth,
Galleria
mellonella
, have been used experimentally to host a range of bacterial and fungal pathogens. In this study we evaluated the suitability of
G
. mellonella
as an alternative animal model of
Salmonella
infection. Using a range of inoculum doses we established that the LD50 of
Salmonella
Typhimurium
strain NCTC 12023 was 3.6 × 103 bacteria per larva. Further, a set of isogenic mutant strains depleted of known virulence factors was tested to identify determinants essential for
S
. Typhimurium
pathogenesis. Mutants depleted of one or both of the type III secretion systems encoded by
Salmonella
Pathogenicity Islands 1 and 2 showed no virulence defect. In contrast, we observed reduced pathogenic potential of a phoQ mutant indicating an important role for the PhoPQ two-component signal transduction system. Lipopolysaccharide (LPS) structure was also shown to influence
Salmonella
virulence in
G
. mellonella
. A waaL (rfaL) mutant, which lacks the entire O-antigen (OAg), was virtually avirulent, while a wzz
ST/wzz
fepE double mutant expressing only a very short OAg was highly attenuated for virulence. Furthermore, shortly after infection both LPS mutant strains showed decreased replication when compared to the wild type in a flow cytometry-based competitive index assay. In this study we successfully established a
G
. mellonella
model of
S
. Typhimurium
infection. By identifying PhoQ and LPS OAg length as key determinants of virulence in the wax moth larvae we proved that there is an overlap between this and other animal model systems, thus confirming that the
G
. mellonella
infection model is suitable for assessing aspects of
Salmonella
virulence function. 相似文献
975.
Johanna Hass Esther Walton Holger Kirsten Jingyu Liu Lutz Priebe Christiane Wolf Nazanin Karbalai Randy Gollub Tonya White Veit Roessner Kathrin U. Müller Tomas Paus Michael N. Smolka Gunter Schumann IMAGEN Consortium Markus Scholz Sven Cichon Vince Calhoun Stefan Ehrlich 《PloS one》2013,8(6)
Patients with schizophrenia and their siblings typically show subtle changes of brain structures, such as a reduction of hippocampal volume. Hippocampal volume is heritable, may explain a variety of cognitive symptoms of schizophrenia and is thus considered an intermediate phenotype for this mental illness. The aim of our analyses was to identify single-nucleotide polymorphisms (SNP) related to hippocampal volume without making prior assumptions about possible candidate genes. In this study, we combined genetics, imaging and neuropsychological data obtained from the Mind Clinical Imaging Consortium study of schizophrenia (n = 328). A total of 743,591 SNPs were tested for association with hippocampal volume in a genome-wide association study. Gene expression profiles of human hippocampal tissue were investigated for gene regions of significantly associated SNPs. None of the genetic markers reached genome-wide significance. However, six highly correlated SNPs (rs4808611, rs35686037, rs12982178, rs1042178, rs10406920, rs8170) on chromosome 19p13.11, located within or in close proximity to the genes NR2F6, USHBP1, and BABAM1, as well as four SNPs in three other genomic regions (chromosome 1, 2 and 10) had p-values between 6.75×10−6 and 8.3×10−7. Using existing data of a very recently published GWAS of hippocampal volume and additional data of a multicentre study in a large cohort of adolescents of European ancestry, we found supporting evidence for our results. Furthermore, allelic differences in rs4808611 and rs8170 were highly associated with differential mRNA expression in the cis-acting region. Associations with memory functioning indicate a possible functional importance of the identified risk variants. Our findings provide new insights into the genetic architecture of a brain structure closely linked to schizophrenia. In silico replication, mRNA expression and cognitive data provide additional support for the relevance of our findings. Identification of causal variants and their functional effects may unveil yet unknown players in the neurodevelopment and the pathogenesis of neuropsychiatric disorders. 相似文献
976.
Kathrin Ströcker Shirley Wendt Wolfgang H. Kirchner Christine Struck 《Arthropod-Plant Interactions》2013,7(5):579-589
The weevils Sitona gressorius and Sitona griseus are specialist herbivores on lupins in Europe. The adult weevils feed on the leaves, and the larvae on the root nodules of the plants. This causes severe damage to lupin crops. In the present study, the feeding preferences of lupin weevil adults on different lupin genotypes were examined with respect to a possible effect of lupin alkaloids on host selection. A total of 12 genotypes from the species Lupinus albus, L. angustifolius, L. luteus, and L. nanus were grown in a field experiment and the feeding damage on the leaves caused by naturally occurring lupin weevil adults was estimated. Additionally, a feeding choice test with S. gressorius adults was performed to examine feeding preferences under laboratory conditions. A gas chromatographic analysis provided information on the alkaloid content and profiles in the leaves of the tested lupin genotypes. In the field experiment, significant differences in the extent of the feeding damage within the 12 lupin genotypes were observed. The dual-choice feeding bioassay did not show discrimination of lupin species, but two L. angustifolius genotypes were significantly less affected than the standard L. luteus “Bornal”. The alkaloid analysis revealed large contrasts in alkaloid concentrations and profiles in the leaves of the tested genotypes. Correlation analysis with the results from the field and laboratory did not indicate a significant influence of the total foliar alkaloid content on the extent of weevil feeding. 相似文献
977.
978.
979.
Ritchie Ho Bernadett Papp Jackson A. Hoffman Bradley J. Merrill Kathrin Plath 《Cell reports》2013,3(6):2113-2126
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980.
Lisa K. McNeil Robert J. Zagursky Shuo L. Lin Ellen Murphy Gary W. Zlotnick Susan K. Hoiseth Kathrin U. Jansen Annaliesa S. Anderson 《Microbiology and molecular biology reviews》2013,77(2):234-252