Nitrogen redistribution from the roots in post-anthesis plants of spring wheat

The aim of this study was to investigate post-anthesis N redistribution from the roots to other organs in the wheat plant. Two cultivars of spring wheat (Triticum aestivum L.) Sport and WL were grown to maturity in culture solution with stepwise-decreasing N supply and ¹⁵N before sampling. The N concentration of dry weight in the roots decreased from anthesis to full maturity. At maturity the root N concentration was 5.5 mg g⁻¹ dry weight for Sport and 4.9 mg g⁻¹ dry weight for WL, while the main shoot N concentration was 2.1 mg g⁻¹ dry weight for Sport and 2.2 mg g⁻¹ dry weight for WL. The roots were a major sink for N taken up post-anthesis and contained the main proportion of the ¹⁵N during the whole post-anthesis period. The N redistributed from the roots contributed 24.3% of the total N amount in the grains at maturity in cv Sport and 8.7% in cv WL. For cv Sport, 46.3% of the root N amount was redistributed to other parts of the plant and for WL 25.4%. The tiller grains were supplied with N from the ¹⁵N applied post-anthesis to a higher degree than the main shoot grains. The transport capability was maintained until 12 days after complete yellowness. We concluded that wheat has a great ability to redistribute nitrogen from the root system to the grains.     

The structural definition of adducts of stoichiometry MX:dppx (1:1) M = Cu, Ag, X = simple anion, dppx=Ph2P(CH2)xPPh2, x = 3-6

Single crystal X-ray structural characterizations are recorded for a wide range of adducts of the form MX:dppx (1:1)_(n), M = silver(I) (predominantly), copper(I), X = simple (pseudo-) halide or oxy-anion (the latter spanning, where accessible, perchlorate, nitrate, carboxylate - a range of increasing basicity), dppx=bis(diphenylphosphino)alkane, Ph₂P(CH₂)_xPPh₂, x = 3-6. Adducts are defined of two binuclear forms: (i) [LM(μ-X)₂L], with each ligand chelating a single metal atom, and (ii) [M(μ-X)₂(μ-(P-L-P′))₂M′] where both ligands L and halides bridge the two metal atoms; a few adducts are defined as polymers, the ligands connecting M(μ-X)₂M′ kernels, this motif persisting in all forms. Synthetic procedures for all adducts have been reported. All compounds have been characterized both in solution (¹H, ¹³C, ³¹P NMR, ESI MS) and in the solid state (IR).     

Tripodal polyphosphine ligands in silver (I) coordination chemistry: Mononuclear cf. polynuclear complex dependence vis-a-vis counterion and ligand to metal ratio

1:2, 1:1, 3:2 and 6:2 AgX:L adducts (where L is a tridentate phosphine, in detail: 1,1,1-tris(diphenylphosphinomethyl)ethane (Me-triphos) and bis(2-diphenylphosphinoethyl)phenylphosphine (Ph-triphos), X = O₃SCF₃, O₃SCH₃, BF₄ or O₂CCF₃) have been synthesized and characterized by IR, NMR (¹H, ³¹P and ¹⁹F) and ESI MS spectroscopy. The stoichiometry of the complexes is strongly dependent on the ligand to metal ratio employed and also on the nature of the counterion. ³¹P NMR (solution) data also show the complexes existing in solution, in some cases, however, disproportionating to adducts of different nuclearity. Oligonuclear species have been detected through ESI MS spectroscopy that has been demonstrated as a powerful tool for the identification of the solution species. AgBF₄:Me-triphos (1:2) has been structurally characterized as [Ag(P,P′-Me-triphos)₂](BF₄) · H₂O · 7/2 MeOH, while Ag(O₃SCF₃): Ph-triphos: H₂O (6:2:4) is a spectacular two-dimensional polymer.     

Immunohistochemical characterization of the distribution of galectin-4 in porcine small intestine.

Galectins are an evolutionarily conserved family of 15 different lectins found in various combinations in virtually every type of animal cell. One of the primary galectins expressed in intestinal epithelium is galectin-4, a tandem-repeat galectin with two carbohydrate-recognition domains in a single polypeptide chain. In the current study, we produced an anti-galectin-4 monoclonal antibody (MAb) for determining the distribution of galectin-4 in porcine small intestine to enhance our understanding of where galectin-4 performs its functions in the small intestine. In immunohistochemistry studies, this MAb detected galectin-4 primarily in the cytoplasm of absorptive epithelial cells lining intestinal villi. Mature epithelial cells at the villous tips stained the most intensely with this MAb, with progressively less intense staining observed along the sides of villi and into the crypts. In addition to its cytoplasmic localization, galectin-4 was also associated with nuclei in villous tip cells, indicating that some galectin-4 may migrate to the nucleus during terminal maturation of these cells. In intestinal crypts, a specific subset of cells, which may be enteroendocrine cells, expressed galectin-4 at a relatively high level. Galectin-4 distribution patterns were similar in all three regions (duodenum, jejunum, and ileum) of porcine small intestine.     

HMGB1: endogenous danger signaling

While foreign pathogens and their products have long been known to activate the innate immune system, the recent recognition of a group of endogenous molecules that serve a similar function has provided a framework for understanding the overlap between the inflammatory responses activated by pathogens and injury. These endogenous molecules, termed alarmins, are normal cell constituents that can be released into the extracellular milieu during states of cellular stress or damage and subsequently activate the immune system. One nuclear protein, High mobility group box-1 (HMGB1), has received particular attention as fulfilling the functions of an alarmin by being involved in both infectious and non-infectious inflammatory conditions. Once released, HMGB1 signals through various receptors to activate immune cells involved in the immune process. Although initial studies demonstrated HMGB1 as a late mediator of sepsis, recent findings indicate HMGB1 to have an important role in models of non-infectious inflammation, such as autoimmunity, cancer, trauma, and ischemia reperfusion injury. Furthermore, in contrast to its pro-inflammatory functions, there is evidence that HMGB1 also has restorative effects leading to tissue repair and regeneration. The complex functions of HMGB1 as an archetypical alarmin are outlined here to review our current understanding of a molecule that holds the potential for treatment in many important human conditions.     

Probability Density Functions Describing 24-Hour Inhalation Rates for Use in Human Health Risk Assessments: An Update and Comparison

Inhalation rates are used for quantifying inhalation health risks. The time-activity-ventilation (TAV) approach has had longstanding acceptance for estimating inhalation rate (IR) as a time-weighted average across a number of activity levels comprising a typical day. Probability density functions (PDFs) describing 24-hour inhalation rates were updated in this study by incorporating supplemental minute volume (V _i ) and time-activity (t _i ) data published since the time of the previous study and by correlating V _i with metabolic equivalents (METs) for the physical activities at the time of measurement. The metabolic correlations are an improvement over the previous study because they enable interpolation to fill data gaps where V _i data are sparse or absent for certain age groups at specific levels of physical activity. The updated PDFs were developed using Monte Carlo simulation and can be described with log normal distributions. The updated PDFs were compared with IR distributions developed through two other approaches: the metabolic energy conversion (MEC) approach; and the doubly labeled water (DLW) approach. Compared to the previous TAV estimates, this study's PDFs suggest lower IR for toddlers and teenagers, higher IR for adults and seniors, and similar IR for infants and children.     

Identification of inhibitors for MDM2 ubiquitin ligase activity from natural product extracts by a novel high-throughput electrochemiluminescent screen

High-throughput screening technologies have revolutionized the manner in which potential therapeutics are identified. Although they are the source of lead compounds for ~65% of anticancer and antimicrobial drugs approved by the Food and Drug Administration between 1981 and 2002, natural products have largely been excluded from modern screening programs. This is due, at least in part, to the inherent difficulties in testing complex extract mixtures, which often contain nuisance compounds, in modern bioassay systems. In this article, the authors present a novel electrochemiluminescent assay system for inhibition of MDM2 activity that is suitable for testing natural product extracts in high-throughput screening systems. The assay was used to screen more than 144,000 natural product extracts. The authors identified 1 natural product, sempervirine, that inhibited MDM2 auto-ubiquitination, MDM2-mediated p53 degradation, and led to accumulation of p53 in cells. Sempervirine preferentially induced apoptosis in transformed cells expressing wild-type p53, suggesting that it could be a potential lead for anticancer therapeutics.     

Summer meeting 2007 - the problems with fresh produce: an overview

In Fall 2006, four separate outbreaks of foodborne illness associated with the consumption of fresh produce occurred in the United States. In follow-up investigations, spinach, lettuce, and tomatoes were identified as the vehicles of illness. Epidemiologic investigations subsequently focused on finding the specific growing regions using traceback records. While the areas most likely involved in the outbreaks have been identified, the specific mode of contamination remains unconfirmed. Suspected risk factors in these cases include: proximity of irrigation wells and surface waterways exposed to faeces from cattle and wildlife; exposure in fields to wild animals and their waste materials; and improperly composted animal manure used as fertilizer. Difficulty in deciphering these and other on-farm routes of contamination is due to the sporadic nature of these events. Hence, evidence to support these contamination modes is based largely on experimental studies in the laboratory and field. Still at issue is the relevance of internalization of pathogens, whether this occurs through the roots and plant vascular tissues of vegetables and fruits or through plant surfaces into cracks and crevices. Potential for these events, conditions under which the events occur, and pathogen survival following these events, are questions that still need to be answered. Answers to these questions will ultimately affect the type of interventions needed for application postharvest. Currently, many chemical and biological interventions can reduce surface pathogens and minimize cross-contamination, however, they are largely ineffective on internalized pathogens. In the event internalization is a significant route of contamination in the field, physical interventions (irradiation and high pressure) may be needed to minimize risk. Ultimately, risk assessment studies will be useful tools in developing risk management strategies for the produce industry.     

Postmortem diagnosis and toxicological validation of illicit substance use.

The present study examines the diagnostic challenges of identifying ante-mortem illicit substance use in human postmortem cases. Substance use, assessed by clinical case history reviews, structured next-of-kin interviews, by general toxicology of blood, urine and/or brain, and by scalp hair testing, identified 33 cocaine, 29 cannabis, 10 phencyclidine and nine opioid cases. Case history identified 42% cocaine, 76% cannabis, 10% phencyclidine and 33% opioid cases. Next-of-kin interviews identified almost twice as many cocaine and cannabis cases as Medical Examiner (ME) case histories, and were crucial in establishing a detailed lifetime substance use history. Toxicology identified 91% cocaine, 68% cannabis, 80% phencyclidine and 100% opioid cases, with hair testing increasing detection for all drug classes. A cocaine or cannabis use history was corroborated by general toxicology with 50% and 32% sensitivity, respectively, and with 82% and 64% sensitivity by hair testing. Hair testing corroborated a positive general toxicology for cocaine and cannabis with 91% and 100% sensitivity, respectively. Case history corroborated hair toxicology with 38% sensitivity for cocaine and 79% sensitivity for cannabis, suggesting that both case history and general toxicology underestimated cocaine use. Identifying ante-mortem substance use in human postmortem cases are key considerations in case diagnosis and for characterization of disorder-specific changes in neurobiology. The sensitivity and specificity of substance use assessments increased when ME case history was supplemented with structured next-of-kin interviews to establish a detailed lifetime substance use history, while comprehensive toxicology, and hair testing in particular, increased detection of recent illicit substance use.