Oxidative stress causes a decline in lysosomal integrity during hypothermic incubation of rat hepatocytes

Oxidative stress during cold preservation has been identified as a significant cause of cell injury but the process by which injury occurs is poorly understood. We examined loss of lysosomal integrity as a possible cause of cell injury during extended cold storage of isolated rat hepatocytes. After 21 h of hypothermia, there was a marked decline in lysosomal integrity, which was correlated with an increase in lipid peroxidation. When lipid peroxidation was prevented with the antioxidant Trolox (a vitamin E analog) or the iron chelator desferrioxamine, lysosomal integrity was preserved. In contrast, increasing lysosomal iron with ferric chloride caused an increase in lipid peroxidation and decreased lysosomal integrity. Loss of lysosomal integrity during cold preservation in this experimental model was consistent with iron-initiated oxidative stress. The progressive loss of lysosomal integrity during hypothermic incubation has the potential to affect liver function after transplantation.     

Kinetic analysis of nanoparticle‐protein interactions using a plasmon waveguide resonance

A plasmon waveguide resonance (PWR) sensor is proposed for studying the interaction between gold nanoparticles and proteins. The ability of the PWR sensor to operate in both TM and TE Polarizations, i.e. its polarization diversity, facilitates the simultaneous spectroscopy of the nanoparticles surface reactions using both polarizations. The response of each polarization to streptavidin‐biotin binding at the surface of gold nanoparticles is investigated in real time. Finally, using the principles of multimode spectroscopy, the nanoparticle's surface reactions are decoupled from the bulk solution refractive index variations.

Schematic diagram of the NP‐modified PWR sensor     

The spatial relationship of the viral and H-2 antigens recognized by anti-viral CTLs

With the use of monospecific rabbit anti-G protein and mouse monoclonal anti-H-2K^k, we have analyzed the spatial relationship of the serologically defined H-2K^k antigens and the major surface glycoprotein (G protein) of vesicular stomatitis virus (VSV) to those antigens recognized by B10.A (k, d) anti-VSV cytotoxic T lymphocytes (CTLs). The ability of monoclonal anti-H-2K^k or rabbit anti-G protein to inhibit specifically the cytolytic activity of B10.A anti-VSV CTLs indicates that the G protein and the H-2K^k molecules are in close proximity to the viral and H-2K^k antigens recognized by the anti-VSV (CTLs. By the method of sequential immunoprecipitation, we also demonstrated that only 10–30 percent of the serologically defined G and H-2K^k molecules are in theG-H-2K ^k complexes.Abbreviations used in this paper Con A Concanavalin A - cpm counts per minure - CTLs cytotoxic T lymphocytes - E: T ratio effector: target ratio - G major surface glycoprotein of VSV - MHC major histocompatibility complex - MOI multiplicity of infection - NP40 Nonidet-P40 - PAGE polyacrylamide gel electrophoresis - PBS phosphate-buffered saline - SaCI Staphylococcus aureus, Cowan I strain - SDS sodium dodecyl sulfate - UV ultraviolet light     

Factors associated with Diaphorina citri immigration into commercial citrus orchards in São Paulo State,Brazil

Seasonality often influences multiple aspects of vector-borne plant diseases. With respect to the management of plant disease vectors, an understanding of the factors driving seasonal changes in vector flight activity may improve management outcomes by facilitating more proactive application of control measures. One of the most challenging issues for citrus Huanglongbing management is to forecast when disease primary spread by bacteriliferous Diaphorina citri will occur. We monitored the temporal patterns of immigrating psyllids, using upwards of 1,200 traps spread among 9 citrus farms and checked on a weekly basis over 4 years. This dataset was analysed with a set of hierarchical models to estimate the effect of climatic variables on citrus foliage production (i.e. flush), and effects of climatic variables and citrus foliage dynamics on D. citri catches over the season. The results showed substantial seasonal variability in immigrating D. citri abundance, with the critical dispersal/migration period occurring between end of winter and spring. During this period, 65% of the total psyllids were collected on sticky traps. Seasonality of immigrating D. citri coincided with changes in certain climate variables, with negative effects of humidity and daily maximum temperatures, and a positive effect of rainfall amount in prior weeks. Maximum temperature and both daily minimum temperature and rainfall during prior weeks were also associated with new citrus flush production, which itself was positively related to immigrating D. citri abundance. Based on these results, citrus growers should be aware and intensify the frequency of psyllid control tactics (i.e. insecticide and/or kaolin sprays) during this period in order to prevent Ca. L. asiaticus transmission. These results are an important step towards developing the predictive framework needed to refine D. citri and huanglongbing management.     

The AutoDock suite at 30

The AutoDock suite provides a comprehensive toolset for computational ligand docking and drug design and development. The suite builds on 30 years of methods development, including empirical free energy force fields, docking engines, methods for site prediction, and interactive tools for visualization and analysis. Specialized tools are available for challenging systems, including covalent inhibitors, peptides, compounds with macrocycles, systems where ordered hydration plays a key role, and systems with substantial receptor flexibility. All methods in the AutoDock suite are freely available for use and reuse, which has engendered the continued growth of a diverse community of primary users and third‐party developers.     

Climate change alters temporal dynamics of alpine soil microbial functioning and biogeochemical cycling via earlier snowmelt

Soil microbial communities regulate global biogeochemical cycles and respond rapidly to changing environmental conditions. However, understanding how soil microbial communities respond to climate change, and how this influences biogeochemical cycles, remains a major challenge. This is especially pertinent in alpine regions where climate change is taking place at double the rate of the global average, with large reductions in snow cover and earlier spring snowmelt expected as a consequence. Here, we show that spring snowmelt triggers an abrupt transition in the composition of soil microbial communities of alpine grassland that is closely linked to shifts in soil microbial functioning and biogeochemical pools and fluxes. Further, by experimentally manipulating snow cover we show that this abrupt seasonal transition in wide-ranging microbial and biogeochemical soil properties is advanced by earlier snowmelt. Preceding winter conditions did not change the processes that take place during snowmelt. Our findings emphasise the importance of seasonal dynamics for soil microbial communities and the biogeochemical cycles that they regulate. Moreover, our findings suggest that earlier spring snowmelt due to climate change will have far reaching consequences for microbial communities and nutrient cycling in these globally widespread alpine ecosystems.Subject terms: Metagenomics, Climate-change ecology, Microbial ecology, Biogeochemistry, Soil microbiology     

TLR9 is required for protective innate immunity in Gram-negative bacterial pneumonia: role of dendritic cells

In this study, experiments were performed to determine the contribution of TLR9 to the generation of protective innate immunity against virulent bacterial pathogens of the lung. In initial studies, we found that the intratracheal administration of Klebsiella pneumoniae in wild-type (WT) BALB/c mice resulted in the rapid accumulation of dendritic cells (DC) expressing TLR9. As compared with WT mice, animals deficient in TLR9 (TLR9-/-) displayed significantly increased mortality that was associated with a >50-fold increase in lung CFU and a >400-fold increase in K. pneumoniae CFU in blood and spleen, respectively. Intrapulmonary bacterial challenge in TLR9-/- mice resulted in reduced lung DC accumulation and maturation as well as impaired activation of lung macrophages, NK cells, and alphabeta and gammadelta T cells. Mice deficient in TLR9 failed to generate an effective Th1 cytokine response following bacterial administration. The adoptive transfer of bone marrow-derived DC from syngeneic WT but not TLR9-/- mice administered intratracheally reconstituted antibacterial immunity in TLR9-/- mice. Collectively, our findings indicate that TLR9 is required for effective innate immune responses against Gram-negative bacterial pathogens and that approaches to maximize TLR9-mediated DC responses may serve as a means to augment antibacterial immunity in pneumonia.