Effects of Litter Addition on Ectomycorrhizal Associates of a Lodgepole Pine (Pinus contorta) Stand in Yellowstone National Park

Increasing soil nutrients through litter manipulation, pollution, or fertilization can adversely affect ectomycorrhizal (EM) communities by inhibiting fungal growth. In this study, we used molecular genetic methods to determine the effects of litter addition on the EM community of a Pinus contorta stand in Yellowstone National Park that regenerated after a stand-replacing fire. Two controls were used; in unmodified control plots nothing was added to the soil, and in perlite plots perlite, a chemically neutral substance, was added to maintain soil moisture and temperature at levels similar to those under litter. We found that (i) species richness did not change significantly following perlite addition (2.6 ± 0.3 species/core in control plots, compared with 2.3 ± 0.3 species/core in perlite plots) but decreased significantly (P < 0.05) following litter addition (1.8 ± 0.3 species/core); (ii) EM infection was not affected by the addition of perlite but increased significantly (P < 0.001) in response to litter addition, and the increase occurred only in the upper soil layer, directly adjacent to the added litter; and (iii) Suillus granulatus, Wilcoxina mikolae, and agaricoid DD were the dominant organisms in controls, but the levels of W. mikolae and agaricoid DD decreased significantly in response to both perlite and litter addition. The relative levels of S. granulatus and a fourth fungus, Cortinariaceae species 2, increased significantly (P < 0.01 and P < 0.05, respectively) following litter addition. Thus, litter addition resulted in some negative effects that may be attributable to moisture-temperature relationships rather than to the increased nutrients associated with litter. Some species respond positively to litter addition, indicating that there are differences in their physiologies. Hence, changes in the EM community induced by litter accumulation also may affect ecosystem function.     

Elucidating the role of copper in CHO cell energy metabolism using 13C metabolic flux analysis

¹³C‐metabolic flux analysis was used to understand copper deficiency‐related restructuring of energy metabolism, which leads to excessive lactate production in recombinant protein‐producing CHO cells. Stationary‐phase labeling experiments with U‐¹³C glucose were conducted on CHO cells grown under high and limiting copper in 3 L fed‐batch bioreactors. The resultant labeling patterns of soluble metabolites were measured by GC‐MS and used to estimate metabolic fluxes in the central carbon metabolism pathways using OpenFlux. Fluxes were evaluated 300 times from stoichiometrically feasible random guess values and their confidence intervals calculated by Monte Carlo simulations. Results from metabolic flux analysis exhibited significant carbon redistribution throughout the metabolic network in cells under Cu deficiency. Specifically, glycolytic fluxes increased (25%–79% relative to glucose uptake) whereas fluxes through the TCA and pentose phosphate pathway (PPP) were lower (15%–23% and 74%, respectively) compared with the Cu‐containing condition. Furthermore, under Cu deficiency, 33% of the flux entering TCA via the pyruvate node was redirected to lactate and malate production. Based on these results, we hypothesize that Cu deficiency disrupts the electron transport chain causing ATP deficiency, redox imbalance, and oxidative stress, which in turn drive copper‐deficient CHO cells to produce energy via aerobic glycolysis, which is associated with excessive lactate production, rather than the more efficient route of oxidative phosphorylation. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 31:1179–1186, 2015     

Caring for Caregivers of People Living with HIV in the Family: A Response to the HIV Pandemic from Two Urban Slum Communities in Pune,India

Introduction

In low resource settings, the vast majority of ‘Person/people Living with HIV’ (PLHIV/s) and inadequate healthcare delivery systems to meet their treatment and care needs, caregivers play a vital role. Home based caregivers are often unrecognized with limited AIDS policies and programs focusing on them. We explored the perceptions and norms regarding care being provided by family caregivers of PLHIVs in India.

Methodology

A community based qualitative study to understand the issues pertaining to home based care for PLHIV was conducted in urban settings of Pune city, in Maharashtra, India. Eight Focus Group Discussions (FGDs) among men, women and peer educators were carried out. A total of 44 in-depth Interviews (IDIs) with PLHIVs (20) and their caregivers (24), were conducted using separate guides respectively. Data was analyzed thematically.

Results

Home based care was perceived as economically viable option available for PLHIVs. ‘Care’ comprised of emotional, adherence, nursing and financial support to PLHIV. Home based care was preferred over hospital based care as it ensured confidentiality and patient care without hampering routine work at home. Women emerged as more vital primary caregivers compared to men. Home based care for men was almost unconditional while women had no such support. The natal family of women also abandoned. Their marital families seemed to provide support. Caregivers voiced the need for respite care and training.

Discussion

Gender related stigma and discrimination existed irrespective of women being the primary family caregivers. The support from marital families indicates a need to explore care and support issues at natal and marital homes of the women living with HIV respectively. Home based care training and respite care for the caregivers is recommended. Gender sensitive interventions addressing gender inequity and HIV related stigma should be modeled while designing interventions for PLHIVs and their family caregivers.     

NMR-based structure of anticancer drug mitoxantrone stacked with terminal base pair of DNA hexamer sequence d-(ATCGAT)2

Mitoxantrone is a promising antitumor drug having considerably reduced cardiotoxicity as compared to anthracyclines. Its binding to deoxyhexanucleotides sequence d-(ATCGAT)₂ has been studied by proton and phosphorous-31 nuclear magnetic resonance spectroscopy. The stoichiometry reveals that 1:1 and 2:1 mitoxantrone-d(ATCGAT)₂ complexes are formed in solution. Significant upfield shifts in 6H/7H, 2H/3H, 11NH, and 12NH protons (～.5?ppm) of mitoxantrone and T6NH imino protons (～.3?ppm) are observed. The phosphorous resonances do not shift significantly indicating that the base pairs do not open at any nucleotide step along the sequence of hexamer. Several inter-molecular Nuclear Overhauser Enhancement connectivities between mitoxantrone and hexanucleotide protons indicate that mitoxantrone chromophore stacks with terminal A1-T6 base pair and side chains involving 12CH₂, 12NH, and 14OH protons are in close proximity of A1, T2, A5, and T6 bases. Absorption and emission spectra show red shift in wavelength maxima, which is characteristic of stacking interaction. At higher mitoxantrone to nucleic acid ratios, electrostatic interactions are dominant. The 2:1 drug/DNA stoichiometric structure obtained by restrained Molecular Dynamics simulations shows considerable distortions in backbone torsional angles and helicoidal parameters although structural fluctuations in 25?ps analysis of trajectory are found to be negligible. Mitoxantrone binds as a monomer at either or both ends of hexamer externally with side chains interacting specifically with DNA. The findings are relevant to the understanding of pharmacological action of drug.     

HIV-1 gp120 induces expression of IL-6 through a nuclear factor-kappa B-dependent mechanism: suppression by gp120 specific small interfering RNA

In addition to its role in virus entry, HIV-1 gp120 has also been implicated in HIV-associated neurocognitive disorders. However, the mechanism(s) responsible for gp120-mediated neuroinflammation remain undefined. In view of increased levels of IL-6 in HIV-positive individuals with neurological manifestations, we sought to address whether gp120 is involved in IL-6 over-expression in astrocytes. Transfection of a human astrocyte cell line with a plasmid encoding gp120 resulted in increased expression of IL-6 at the levels of mRNA and protein by 51.3±2.1 and 11.6±2.2 fold respectively; this effect of gp120 on IL-6 expression was also demonstrated using primary human fetal astrocytes. A similar effect on IL-6 expression was observed when primary astrocytes were treated with gp120 protein derived from different strains of X4 and R5 tropic HIV-1. The induction of IL-6 could be abrogated by use of gp120-specific siRNA. Furthermore, this study showed that the NF-κB pathway is involved in gp120-mediated IL-6 over-expression, as IKK-2 and IKKβ inhibitors inhibited IL-6 expression by 56.5% and 60.8%, respectively. These results were also confirmed through the use of NF-κB specific siRNA. We also showed that gp120 could increase the phosphorylation of IκBα. Furthermore, gp120 transfection in the SVGA cells increased translocation of NF-κB from cytoplasm to nucleus. These results demonstrate that HIV-1 gp120-mediated over-expression of IL-6 in astrocytes is one mechanism responsible for neuroinflammation in HIV-infected individuals and this is mediated by the NF-κB pathway.