Microbial biomass, soil ammonium and nitrate in a secondary successional chronosequence.

General EcologyWe studied the microbial biomass, soil ammonium and nitrate in a secondary successional chronosequence. We wanted to know if nitrite, amino-N, or total microbial N content in soils vary with forest stand age. We also wanted to know if there was a relationship between amino-N and ammonium and if there was a relationship between amino-N and nitrate. To assess the soils, we collected a total of 90 samples from the burn plot chronosequence on the University of Michigan Biological Station (UMBS) property. Soils were collected from the 1911, 1936, 1948, 1954, 1980 and 1998 burn plots. Soils were sieved and picked through to remove fine roots and other debris such as twigs and pebbles that could interfere with our date. Soils then were taken to the lab to be homogenized and weighed out. The soils were then separated into fumigated and non-fumigated samples and KCL extractions and chloroform tests were run on the samples. We found that there was no significance across the chronosequence in nitrite, amino-N or total microbial N related to forest age stand. We also found no significant relationship between amino-N and nitrate but we did find a significant relationship between amino-N and ammonium. Future studies should be run to understand how microbes are affecting nutrient cycling in secondary successional chronosequences and the types of microbes present.http://deepblue.lib.umich.edu/bitstream/2027.42/116853/1/Muckenthaler_Kaylin_2015.pd

The ORNL-SNAP shielding program

The effort in the ORNL-SNAP shielding program is directed toward the development and verification of computer codes using numerical solutions to the transport equation for the design of optimized radiation shields for SNAP power systems. A brief discussion is given for the major areas of the SNAP shielding program, which are cross-section development, transport code development, and integral experiments. Detailed results are presented for the integral experiments utilizing the TSF-SNAP reactor. Calculated results are compared with experiments for neutron and gamma-ray spectra from the bare reactor and as transmitted through slab shields

Hyperferritinaemia-cataract syndrome: Worldwide mutations and phenotype of an increasingly diagnosed genetic disorder

The hereditary hyperferritinaemia-cataract syndrome (HHCS) is characterised by an autosomal dominant cataract and high levels of serum ferritin without iron overload. The cataract develops due to L-ferritin deposits in the lens and its pulverulent aspect is pathognomonic. The syndrome is caused by mutations within the iron-responsive element of L-ferritin. These mutations prevent efficient binding of iron regulatory proteins 1 and 2 to the IRE in L-ferritin mRNA, resulting in an unleashed ferritin translation. This paper reviews all 31 mutations (27 single nucleotide transitions and four deletions) that have been described since 1995. Laboratory test showing hyperferritinaemia, normal serum iron and normal transferrin saturation are indicative for HHCS after exclusion of other causes of increased ferritin levels (inflammation, malignancy, alcoholic liver disease) and should prompt an ophthalmological consultation for diagnostic confirmation. Invasive diagnostics such as liver biopsy are not indicated. HHCS is an important differential diagnosis of hyperferritinaemia. Haematologists, gastroenterologists and ophthalmologists should be aware of this syndrome to spare patients from further invasive diagnosis (liver biopsy), and also from a false diagnosis of hereditary haemochromatosis followed by venesections. Patients diagnosed with HHCS should be counselled regarding the relative harmlessness of this genetic disease, with early cataract surgery as the only clinical consequence

The geographical ancestry affects normal hemoglobin values in high-altitude residents

Increasing the hemoglobin (Hb) concentration is a major mechanism adjusting arterial oxygen content to decreased oxygen partial pressure of inspired air at high altitude. Approximately 5% of the world's population living at altitudes higher than 1500 m shows this adaptive mechanism. Notably, there is a wide variation in the extent of increase in Hb concentration among different populations. This short review summarizes available information on Hb concentrations of high-altitude residents living at comparable altitudes (3500-4500 m) in different regions of the world. An increased Hb concentration is found in all high-altitude populations. The highest mean Hb concentration was found in adult male Andean residents and in Han-Chinese living at high altitude, whereas it was lowest in Ethiopians, Tibetans, and Sherpas. A lower plasma volume in Andean high altitude natives may offer a partial explanation. Indeed, male Andean high-altitude natives have a lower plasma volume than Tibetans and Ethiopians. Moreover, Hb values were lower in adult, non-pregnant females than in males; differences between populations of different ancestry were less pronounced. Various genetic polymorphisms were detected in high altitude residents thought to favor life in a hypoxic environment, some of which correlate with the relatively low Hb concentration in the Tibetans and Ethiopians, whereas differences in angiotensin-converting enzyme allele-distribution may be related to elevated Hb in the Andeans. Taken together these results indicate different sensitivity of oxygen dependent control of erythropoiesis or plasma volume among populations of different geographical ancestry, offering explanations for differences in the Hb concentration at high altitude

RNA degradation compromises the reliability of microRNA expression profiling

Background: MicroRNAs are small non-coding RNAs that post-transcriptionally regulate gene expression and their expression is frequently altered in human diseases, including cancer. To correlate clinically relevant parameters with microRNA expression, total RNA is frequently prepared from samples that were archived for various time periods in frozen tissue banks but, unfortunately, RNA integrity is not always preserved in these frozen tissues. Here, we investigate whether experimentally induced RNA degradation affects microRNA expression profiles. Results: Tissue samples were maintained on ice for defined time periods prior to total RNA extraction, which resulted in different degrees of RNA degradation. MicroRNA expression was then analyzed by microarray analysis (miCHIP) or microRNA-specific real-time quantitative PCR (miQPCR). Our results demonstrate that the loss of RNA integrity leads to in unpredictability of microRNA expression profiles for both, array-based and miQPCR assays. Conclusion: MicroRNA expression cannot be reliably profiled in degraded total RNA. For the profiling of microRNAs we recommend use of RNA samples with a RNA integrity number equal to or above seven

The IronChip evaluation package: a package of perl modules for robust analysis of custom microarrays

<p>Abstract</p> <p>Background</p> <p>Gene expression studies greatly contribute to our understanding of complex relationships in gene regulatory networks. However, the complexity of array design, production and manipulations are limiting factors, affecting data quality. The use of customized DNA microarrays improves overall data quality in many situations, however, only if for these specifically designed microarrays analysis tools are available.</p> <p>Results</p> <p>The IronChip Evaluation Package (ICEP) is a collection of Perl utilities and an easy to use data evaluation pipeline for the analysis of microarray data with a focus on data quality of custom-designed microarrays. The package has been developed for the statistical and bioinformatical analysis of the custom cDNA microarray IronChip but can be easily adapted for other cDNA or oligonucleotide-based designed microarray platforms. ICEP uses decision tree-based algorithms to assign quality flags and performs robust analysis based on chip design properties regarding multiple repetitions, ratio cut-off, background and negative controls.</p> <p>Conclusions</p> <p>ICEP is a stand-alone Windows application to obtain optimal data quality from custom-designed microarrays and is freely available here (see "Additional Files" section) and at: <url>http://www.alice-dsl.net/evgeniy.vainshtein/ICEP/</url></p

Two to Tango: Regulation of Mammalian Iron Metabolism

Disruptions in iron homeostasis from both iron deficiency and overload account for some of the most common human diseases. Iron metabolism is balanced by two regulatory systems, one that functions systemically and relies on the hormone hepcidin and the iron exporter ferroportin, and another that predominantly controls cellular iron metabolism through iron-regulatory proteins that bind iron-responsive elements in regulated messenger RNAs. We describe how the two distinct systems function and how they “tango” together in a coordinated manner. We also highlight some of the current questions in mammalian iron metabolism and discuss therapeutic opportunities arising from a better understanding of the underlying biological principles

The Increase in Hemoglobin Concentration With Altitude Differs Between World Regions and Is Less in Children Than in Adults

To compensate for decreased oxygen partial pressure, high-altitude residents increase hemoglobin concentrations [Hb]. The elevation varies between world regions, posing problems in defining cutoff values for anemia or polycythemia. The currently used altitude adjustments (World Health Organization [WHO]), however, do not account for regional differences. Data from The Demographic and Health Survey (DHS) Program were analyzed from 32 countries harboring >4% of residents at altitudes above 1000 m. [Hb]-increase, (ΔHb/km altitude) was calculated by linear regression analysis. Tables show 95% reference intervals (RIs) for different altitude ranges, world regions, and age groups. The prevalence of anemia and polycythemia was calculated using regressions in comparison to WHO adjustments. The most pronounced Δ[Hb]/km was found in East Africans and South Americans while [Hb] increased least in South/South-East Asia. In African regions and Middle East, [Hb] was decreased in some altitude regions showing inconsistent changes in different age groups. Of note, in all regions, the Δ[Hb]/km was lower in children than in adults, and in the Middle East, it was even negative. Overall, the Δ[Hb]/km from our analysis differed from the region-independent adjustments currently suggested by the WHO resulting in a lower anemia prevalence at very high altitudes. The distinct patterns of Δ[Hb] with altitude in residents from different world regions imply that one single, region-independent correction factor for altitude is not be applicable for diagnosing abnormal [Hb]. Therefore, we provide regression coefficients and reference-tables that are specific for world regions and altitude ranges to improve diagnosing abnormal [Hb]