Mycelia promote active transport and spatial dispersion of polycyclic aromatic hydrocarbons

To cope with heterogeneous subsurface environments mycelial microorganisms have developed a unique ramified growth form. By extending hyphae, they can obtain nutrients from remote places and transport them even through air gaps and in small pore spaces, repectively. To date, studies have been focusing on the role that networks play in the distribution of nutrients. Here, we investigated the role of mycelia for the translocation of nonessential substances, using polycyclic aromatic hydrocarbons (PAHs) as model compounds. We show that the hyphae of the mycelial soil oomycete Pythium ultimum function as active translocation vectors for a wide range of PAHs. Visualization by two-photon excitation microscopy (TPEM) demonstrated the uptake and accumulation of phenanthrene (PHE) in lipid vesicles and its active transport by cytoplasmic streaming of the hyphae ('hyphal pipelines'). In mycelial networks, contaminants were translocated over larger distances than by diffusion. Given their transport capacity and ubiquity, hyphae may substantially distribute remote hydrophobic contaminants in soil, thereby improving their bioavailability to bacterial degradation. Hyphal contaminant dispersal may provide an untapped potential for future bioremediation approaches.     

A system for seismocardiography-based identification of quiescent heart phases: implications for cardiac imaging

Seismocardiography (SCG), a representation of mechanical heart motion, may more accurately determine periods of cardiac quiescence within a cardiac cycle than the electrically derived electrocardiogram (EKG) and, thus, may have implications for gating in cardiac computed tomography. We designed and implemented a system to synchronously acquire echocardiography, EKG, and SCG data. The device was used to study the variability between EKG and SCG and characterize the relationship between the mechanical and electrical activity of the heart. For each cardiac cycle, the feature of the SCG indicating Aortic Valve Closure was identified and its time position with respect to the EKG was observed. This position was found to vary for different heart rates and between two human subjects. A color map showing the magnitude of the SCG acceleration and computed velocity was derived, allowing for direct visualization of quiescent phases of the cardiac cycle with respect to heart rate.     

Simulating Retention in Gas–Liquid Chromatography: Benzene, Toluene, and Xylene Solutes

Accurate predictions of retention times, retention indices, and partition constants are a long sought-after goal for theoretical studies in chromatography. Although advances in computational chemistry have improved our understanding of molecular interactions, little attention has been focused on chromatography, let alone calculations of retention properties. Configurational-bias Monte Carlo simulations in the isobaric–isothermal Gibbs ensemble were used to investigate the partitioning of benzene, toluene, and the three xylene isomers between a squalane liquid phase and a helium vapor phase. The united-atom representation of the TraPPE (transferable potentials for phase equilibria) force field was used for all solutes and squalane. The Gibbs free energies of transfer and Kovats retention indices of the solutes were calculated directly from the partition constants (which were averaged over several independent simulations). While the calculated Kovats indices of benzene and toluene at T=403 K are significantly higher than their experimental counterparts, much better agreement is found for the xylene isomers at T=365 K.     

Effects of cytokine application on glucocorticoid secretion in an animal model for systemic scleroderma

We previously reported on an altered immune-endocrine feedback loop via the hypothalamo-pituitary-adrenal (HPA) axis in Obese strain (OS) chickens afflicted with spontaneous autoimmune thyroiditis. These animals are deficient in plasma corticosterone increase after antigenic challenge or application of cytokine-containing conditioned medium of mitogen-stimulated spleen cells (CM). To investigate whether the impaired ability to respond to cytokines with glucocorticoid-increasing factor (GIF) activity, e.g. interleukin 1 (IL 1), is restricted to OS chickens as a model for an organ-specific autoimmune disease, we extended our experiments to another autoimmune-prone animal strain, the chickens of the University of California at Davis line 200 (UCD-200). These animals develop an inherited inflammatory fibrotic disease that closely resembles human progressive systemic sclerosis (scleroderma). Application of GIF-containing CM to UCD-200 chickens leads to a transient increase in glucocorticoid serum levels within 1-2 hours comparable to that of controls. But, while corticosterone levels in the latter returned to normal baseline levels after 4 hours, they were still elevated in autoimmune chickens. Although the peak of the glucocorticoid hormone serum concentrations was equal to that of controls, UCD-200 had to secrete twice as much adrenocorticotropic hormone to achieve this corticosterone serum level due to an apparent hyporesponsiveness of the adrenal gland to this secretagogue. The altered cytokine-induced glucocorticoid secretion is found in early as well as in chronic, sclerotic stages of the disease. Cellular alterations in the peripheral blood of UCD-200 chickens during the prolonged elevated corticosterone section, i.e. between 2-4 hours after CM application, are characterized by a significant decrease in the percentage of CD4+ and CD8+ cells. Furthermore, a significant increase in B cells up to 24 hours with a maximum after 1 hour was found. The proliferative response to the mitogen concanavalin A of peripheral mononuclear cells was inversely correlated to the serum corticosterone level, showing a permanent decrease of 80-90% after 1-4 hours in autoimmune animals. This functional alteration in UCD-200 was accompanied by an 80% decrease in serum interleukin 2 (sIL 2) activity 4 hours after CM application. Twenty-four hours later an eight-fold increase in sIL 2 rebound activity was found, indicating that the inhibitory effect of corticosterone in UCD-200 chickens is not long-lasting.     

Solitary syringoma. Report of five cases and clinicopathologic comparison with microcystic adnexal carcinoma of the skin

Interleukin-1 receptor antagonist (IL-1ra) competes with IL-1 for binding of the IL-1 receptor, but does not elicit a cellular immune response. This study was designed to evaluate the effectiveness of IL-1ra in the immune and inflammatory responses to rat heart allografts. Experimental design was as follows: Group I HTx was syngeneic, BN to BN. The remaining groups were DA (RT 1a) to BN (RT 1n) allogeneic HTx. Group II was transplanted without immunosuppression. Group III received a low-dose IL-1ra regimen via osmotic pump into the peritoneum. Group IV recipients were similarly treated with a higher dose IL-1ra regimen. Group V rats received subtherapeutic cyclosporine (CsA) therapy while Group VI was treated with both CsA and low-dose IL-1ra. Group I rats survived indefinitely. Group II rats rejected their grafts at 5.33 +/- 1.37 days. Group III grafts survived for 7.16 +/- 0.48 days, and Group IV grafts for 8.16 +/- 0.75 days, both significantly longer than in Group II (P < 0.01). Group V animals treated with low-dose CsA had graft survival of 7.7 +/- 1.6 days, but combined therapy with CsA and IL-1ra in Group VI yielded significantly prolonged graft survival of 17.2 +/- 1.3 days (P < 0.0001). Histologic examination in treated recipients revealed delayed appearance of mononuclear cell infiltration. IL-1ra-treated recipients all demonstrated significantly reduced numbers of graft-infiltrating leukocytes; all phenotype subsets were equally affected. This study demonstrates the effectiveness of IL-1ra, in combination with low-dose CsA, in reducing the inflammatory response and rejection in the transplant setting.     

Precise measurement of Birks kB parameter in plastic scintillators

The scintillation response of different types of plastic scintillators to electrons and protons was studied experimentally with high precision. Equivalent electron and proton energies yielding the same amount of light output have been measured. The results were analyzed in terms of a semi-empirical formula proposed by J.B. Birks (1951)     

A semiconserved residue inhibits complex formation by stabilizing interactions in the free state of a theophylline-binding RNA

The theophylline-binding RNA aptamer contains a 15 nucleotide motif that is required for high-affinity ligand binding. One residue within this RNA motif is only semiconserved and can be an A or C. This residue, C27, was disordered in the previously determined three-dimensional structure of the complex, suggesting that it is dynamic in solution. 13C Relaxation measurements are reported here, demonstrating that C27 is highly dynamic in the otherwise well-ordered RNA-theophylline complex. A synthetic complex with an abasic residue at position 27 was found to exhibit wild-type binding affinity (Kd approximately 0.2 microM), indicating that the base of residue 27 is not directly involved with theophylline binding. Surprisingly, the U27 and G27 RNAs were found to bind theophylline with low affinity (Kd values > 4 microM). NMR spectroscopy on the U27 RNA revealed the presence of an A7-U27 base pair in the free RNA that prevents formation of a critical base-platform structural motif and therefore blocks theophylline binding. Similarly, a protonated A7H+-C27 base pair forms in the absence of theophylline at low pH, which explains the unusual pH dependence of theophylline binding of the C27 RNA aptamer. Thus the weak binding for various nucleotides at position 27 arises not from unfavorable interactions in the RNA-theophylline complex but instead from stable interactions in the free state of the RNA that inhibit theophylline binding.     

Identification of a genomic locus containing three slow myosin heavy chain genes in the chicken

Gene technology using polymerase chain reaction (PCR) has markedly advanced in recent year and has been introduced in clinical laboratories. In this paper, the genotypes of genomic DNAs of subjects with cisAB blood group were analysed using three methods, polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP), and the PCR-direct sequencing method, and directly determined using the polymerase chain reaction (PCR) amplification of specific alleles (PASA)-method. The differences among the methods were as follows, PCR-RFLP and PCR-direct sequencing method require 2-step procedures, and are complicated for clinical laboratories. The PASA method is based on the fact that PCR amplification occurs only when the 3' endbase of the primer is matched to sites of the nucleotide substitution of ABO allelic cDNA. Three of five regions of allelic DNAs were co-amplified in a single PCR (multiplex-PCR) in this study. ABO and cisAB blood group genotypes were directly determined, based on the molecular size of allele-specific amplification products. The PASA method requires only about 4 hours from starting PCR to results, making it rapid, simple and useful for detecting the genotype of ABO and cisAB blood groups in comparison with PCR-RFLP and the direct sequencing methods and will allow this procedure to be very versatile and widely used throughout the research and clinical diagnostic communities. The analyses of the nucleotide sequence at nucleotides No. 261, 526, 703, 796 and 803 in 3 major subjects in the cisAB blood group (cisA2B3, cisA1B3 and cisA2B) revealed chimeric structures of the A allele and B allele on the same gene.