The human neonatal small intestine has the potential for arginine synthesis; developmental changes in the expression of arginine-synthesizing and -catabolizing enzymes

BACKGROUND: Milk contains too little arginine for normal growth, but its precursors proline and glutamine are abundant; the small intestine of rodents and piglets produces arginine from proline during the suckling period; and parenterally fed premature human neonates frequently suffer from hypoargininemia. These findings raise the question whether the neonatal human small intestine also expresses the enzymes that enable the synthesis of arginine from proline and/or glutamine. Carbamoylphosphate synthetase (CPS), ornithine aminotransferase (OAT), argininosuccinate synthetase (ASS), arginase-1 (ARG1), arginase-2 (ARG2), and nitric-oxide synthase (NOS) were visualized by semiquantitative immunohistochemistry in 89 small-intestinal specimens. RESULTS: Between 23 weeks of gestation and 3 years after birth, CPS- and ASS-protein content in enterocytes was high and then declined to reach adult levels at 5 years. OAT levels declined more gradually, whereas ARG-1 was not expressed. ARG-2 expression increased neonatally to adult levels. Neurons in the enteric plexus strongly expressed ASS, OAT, NOS1 and ARG2, while varicose nerve fibers in the circular layer of the muscularis propria stained for ASS and NOS1 only. The endothelium of small arterioles expressed ASS and NOS3, while their smooth-muscle layer expressed OAT and ARG2. CONCLUSION: The human small intestine acquires the potential to produce arginine well before fetuses become viable outside the uterus. The perinatal human intestine therefore resembles that of rodents and pigs. Enteral ASS behaves as a typical suckling enzyme because its expression all but disappears in the putative weaning period of human infants

Role of Serum Brain Derived Neurotrophic Factor and Central N-Acetylaspartate for Clinical Response under Antidepressive Pharmacotherapy

Background: The predictive therapeutic value of brain derived neurotrophic factor (BDNF) and its changes associated with the use of specific antidepressants are still unclear. In this study, we examined BDNF as a peripheral and NAA as a central biomarker over the time course of antidepressant treatment to specify both of their roles in the response to the medication and clinical outcome. Methods: We examined serum BDNF (ELISA kit) in a sample of 76 (47 female and 29 male) depressed patients in a naturalistic setting. BDNF was assessed before medication and subsequently after two, four and six weeks of antidepressant treatment. Additionally, in fifteen patients, N-acetylaspartate (NAA) was measured in the anterior cingulate cortex (ACC) with magnetic resonance spectroscopy (MRS). Over a time course of six weeks BDNF and NAA were also examined in a group of 41 healthy controls. Results: We found significant lower serum BDNF concentrations in depressed patients compared to the sample of healthy volunteers before and after medication. BDNF and clinical symptoms decreased significantly in the patients over the time course of antidepressant treatment. Serum BDNF levels at baseline predicted the symptom outcome after eight weeks. Specifically, responders and remitters had lower serum BDNF at baseline than the nonresponders and nonremitters. NAA was slightly decreased but not significantly lower in depressed patients when compared with healthy controls. During treatment period, NAA showed a tendency to increase. Limitations: A relative high drop-out rate and possibly, a suboptimal observation period for BDNF. Conclusion: Our data confirm serum BDNF as a biomarker of depression with a possible role in response prediction. However, our findings argue against serum BDNF increase being a prerequisite to depressive symptom reduction

Proceedings of the CIKM 2020 Workshops

The study of online inquiry competences (OIC) is an important topic on the information literacy (IL) field. Most of the work has been focused on higher education and high-school students, while less has been done regarding primary education. In this work we investigate the effects of an OIC teaching intervention on search performance of a large group of sixth graders from Finland. Our preliminary results show significant improvements in search performance on the intervened group of students compared to a control group when working on a science research task. This work shed light about the potential benefits of a particular approach to develop OIC on elementary school students.</p

The Beaker phenomenon and the genomic transformation of northwest Europe

From around 2750 to 2500 bc, Bell Beaker pottery became widespread across western and central Europe, before it disappeared between 2200 and 1800 bc. The forces that propelled its expansion are a matter of long-standing debate, and there is support for both cultural diffusion and migration having a role in this process. Here we present genome-wide data from 400 Neolithic, Copper Age and Bronze Age Europeans, including 226 individuals associated with Beaker-complex artefacts. We detected limited genetic affinity between Beaker-complex-associated individuals from Iberia and central Europe, and thus exclude migration as an important mechanism of spread between these two regions. However, migration had a key role in the further dissemination of the Beaker complex. We document this phenomenon most clearly in Britain, where the spread of the Beaker complex introduced high levels of steppe-related ancestry and was associated with the replacement of approximately 90% of Britain’s gene pool within a few hundred years, continuing the east-to-west expansion that had brought steppe-related ancestry into central and northern Europe over the previous centuries

Information Competences and Academic Achievement: A Dataset

Information literacy (IL) is becoming fundamental in the modern world. Although several IL standards and assessments have been developed for secondary and higher education, there is still no agreement about the possible associations between IL and both academic achievement and student dropout rates. In this article, we present a dataset including IL competences measurements, as well as academic achievement and socioeconomic indicators for 153 Chilean first- and second-year engineering students. The dataset is intended to allow researchers to use machine learning methods to study to what extent, if any, IL and academic achievement are related

How landmark suitability shapes recognition memory signals for objects in the medial temporal lobes

© 2017 Elsevier Inc. A role of perirhinal cortex (PrC) in recognition memory for objects has been well established. Contributions of parahippocampal cortex (PhC) to this function, while documented, remain less well understood. Here, we used fMRI to examine whether the organization of item-based recognition memory signals across these two structures is shaped by object category, independent of any difference in representing episodic context. Guided by research suggesting that PhC plays a critical role in processing landmarks, we focused on three categories of objects that differ from each other in their landmark suitability as confirmed with behavioral ratings (buildings \u3e trees \u3e aircraft). Participants made item-based recognition-memory decisions for novel and previously studied objects from these categories, which were matched in accuracy. Multi-voxel pattern classification revealed category-specific item-recognition memory signals along the long axis of PrC and PhC, with no sharp functional boundaries between these structures. Memory signals for buildings were observed in the mid to posterior extent of PhC, signals for trees in anterior to posterior segments of PhC, and signals for aircraft in mid to posterior aspects of PrC and the anterior extent of PhC. Notably, item-based memory signals for the category with highest landmark suitability ratings were observed only in those posterior segments of PhC that also allowed for classification of landmark suitability of objects when memory status was held constant. These findings provide new evidence in support of the notion that item-based memory signals for objects are not limited to PrC, and that the organization of these signals along the longitudinal axis that crosses PrC and PhC can be captured with reference to landmark suitability

Genetic Interaction of an Origin Recognition Complex Subunit and the Polycomb Group Gene MEDEA during Seed Development

The eukaryotic origin recognition complex (ORC) is made up of six subunits and functions in nuclear DNA replication, chromatin structure, and gene silencing in both fungi and metazoans. We demonstrate that disruption of a plant ORC subunit homolog, AtORC2 of Arabidopsis (Arabidopsis thaliana), causes a zygotic lethal mutant phenotype (orc2). Seeds of orc2 abort early, typically producing embryos with up to eight cells. Nuclear division in the endosperm is arrested at an earlier developmental stage: only approximately four nuclei are detected in orc2 endosperm. The endosperm nuclei in orc2 are dramatically enlarged, a phenotype that is most similar to class B titan mutants, which include mutants in structural maintenance of chromosomes (SMC) cohesins. The highest levels of ORC2 gene expression were found in preglobular embryos, coinciding with the stage at which homozygous orc2 mutant seeds arrest. The homologs of the other five Arabidopsis ORC subunits are also expressed at this developmental stage. The orc2 mutant phenotype is partly suppressed by a mutation in the Polycomb group gene MEDEA. In double mutants between orc2 and medea (mea), orc2 homozygotes arrest later with a phenotype intermediate between those of mea and orc2 single mutants. Either alterations in chromatin structure or the release of cell cycle checkpoints by the mea mutation may allow more cell and nuclear divisions to occur in orc2 homozygous seeds

Seasonal Patterns of Nitrogen and Phosphorus Limitation in Four German Lakes and the Predictability of Limitation Status from Ambient Nutrient Concentrations

<div><p>To identify the seasonal pattern of nitrogen (N) and phosphorus (P) limitation of phytoplankton in four different lakes, biweekly experiments were conducted from the end of March to September 2011. Lake water samples were enriched with N, P or both nutrients and incubated under two different light intensities. Chlorophyll <i>a</i> fluorescence (Chla) was measured and a model selection procedure was used to assign bioassay outcomes to different limitation categories. N and P were both limiting at some point. For the shallow lakes there was a trend from P limitation in spring to N or light limitation later in the year, while the deep lake remained predominantly P limited. To determine the ability of in-lake N:P ratios to predict the relative strength of N vs. P limitation, three separate regression models were fit with the log-transformed ratio of Chla of the P and N treatments (Response ratio = RR) as the response variable and those of ambient total phosphorus:total nitrogen (TN:TP), dissolved inorganic nitrogen:soluble reactive phosphorus (DIN:SRP), TN:SRP and DIN:TP mass ratios as predictors. All four N:P ratios had significant positive relationships with RR, such that high N:P ratios were associated with P limitation and low N:P ratios with N limitation. The TN:TP and DIN:TP ratios performed better than the DIN:SRP and TN:SRP in terms of misclassification rate and the DIN:TP ratio had the highest <i>R²</i> value. Nitrogen limitation was predictable, frequent and persistent, suggesting that nitrogen reduction could play a role in water quality management. However, there is still uncertainty about the efficacy of N restriction to control populations of N₂ fixing cyanobacteria.</p></div

Arabidopsis MSI1 is a component of the MEA/FIE Polycomb group complex and required for seed development

Seed development in angiosperms initiates after double fertilization, leading to the formation of a diploid embryo and a triploid endosperm. The active repression of precocious initiation of certain aspects of seed development in the absence of fertilization requires the Polycomb group proteins MEDEA (MEA), FERTILIZATION-INDEPENDENT ENDOSPERM (FIE) and FERTILIZATION-INDEPENDENT SEED2. Here we show that the Arabidopsis WD-40 domain protein MSI1 is present together with MEA and FIE in a 600 kDa complex and interacts directly with FIE. Mutant plants heterozygous for msi1 show a seed abortion ratio of 50% with seeds aborting when the mutant allele is maternally inherited, irrespective of a paternal wild-type or mutant MSI1 allele. Further more, msi1 mutant gametophytes initiate endosperm development in the absence of fertilization at a high penetrance. After pollination, only the egg cell becomes fertilized, the central cell starts dividing prior to fertilization, resulting in the formation of seeds containing embryos surrounded by diploid endosperm. Our results establish that MSI1 has an essential function in the correct initiation and progression of seed development