Endophytic bacteria enhancing growth and disease resistance of potato (Solanum tuberosum L.)

Priming plants by non-pathogenic bacteria allows the host to save energy and to reduce time needed for development of defense reaction during a pathogen attack. However, information on the role of endophytes in plant defense is limited. Here, the ability of endophytic bacteria to promote growth and resistance of potato plants towards infection by the necrotroph Pectobacterium atrosepticum was studied. A Pseudomonas sp. strain was selected due to antagonism towards bacterial pathogens and a Methylobacterium sp. strain because of efficient plant colonization. The aim of this study was to find if there is any correlation between plant growth promotion and induction of resistance by endophytes of potato, as well as to study the putative mechanisms of endophytes interacting with the plant during resistance induction. Both tested strains promoted growth of potato shoots but only the Pseudomonas sp. increased potato resistance towards the soft rot disease. Induction of disease resistance by the Methylobacterium sp. was inversely proportional to the size of bacterial population used for inoculation. The plant antioxidant system was moderately activated during the induction of resistance by the biocontrol strains. qPCR data on expression of marker genes of induced systemic resistance and acquired systemic resistance in endophyte-infected Arabidopsis plants showed activation of both salicylic acid and jasmonate/ethylene-dependent pathways after challenge inoculation with the pathogen. We suggest that some endophytes have the potential to activate both basal and inducible plant defense systems, whereas the growth promotion by biocontrol strains may not correlate with induction of disease resistance.     

An algorithm for online detection of temporal changes in operator cognitive state using real-time psychophysiological data

We consider the problem of on-the-fly detection of temporal changes in the cognitive state of human subjects due to varying levels of difficulty of performed tasks using real-time EEG and EOG data. We construct the Cognitive State Indicator (CSI) as a function that projects the multidimensional EEG/EOG signals onto the interval [0,1] by maximizing the Kullback–Leibler distance between distributions of the signals, and whose values change continuously with variations in cognitive load. During offline testing (i.e., when evolution in time is disregarded) it was demonstrated that the CSI can serve as a statistically significant discriminator between states of different cognitive loads. In the online setting, a trend detection heuristic (TDH) has been proposed to detect real-time changes in the cognitive state by monitoring trends in the CSI. Our results support the application of the CSI and the TDH in future closed-loop control systems with human supervision.     

Acute Clearance of Human Metapneumovirus Occurs Independently of Natural Killer Cells

Human metapneumovirus (HMPV) is a major cause of respiratory disease. The role of NK cells in protection against HMPV is unclear. We show that while HMPV-infected C57BL/6 mice had higher numbers of functional lung NK cells than mock-treated mice, comparing NK cell-depleted and control mice did not reveal differences in lung viral titers, histopathology, cytokine levels, or T cell numbers or function. These data indicate that NK cells are not required for host control of HMPV.     

A theoretical expression for drying time of thin lumber

An analytical expression for the drying time of thin lumber is derived, based on a method presented in this study. The laws of moisture content change in wood as function of mass transfer are used for the theoretical approach. The diffusion equation for moisture content is set up for a three-dimensional block of lumber based on the assumption of uniform initial distribution of moisture throughout the specimen. The boundary condition stipulates that the moisture gradient at the boundary is proportional to the deviation of the moisture content of the slab from the equilibrium value at that temperature. These conditions are used to derive an analytical expression for the time required to get from an initial moisture distribution to a desired final moisture content of thin lumber. For a sample calculation, the result of drying time agrees within 10% with the prediction of previously published analytical formulas for the drying curve.     

Production of N-sulfated polysaccharides using yeast-expressed N-deacetylase/N-sulfotransferase-1 (NDST-1)

Heparan sulfate/heparin N-deacetylase/N-sulfotransferase-1 (NDST-1) is a critical enzyme involved in heparan sulfate/heparin biosynthesis. This dual-function enzyme modifies the GlcNAc-GlcA disaccharide repeating sugar backbone to make N-sulfated heparosan. N-sulfation is an absolute requirement for the subsequent epimerization and O-sulfation steps in heparan sulfate/heparin biosynthesis. We have expressed rat liver (r) NDST-1 in Saccharomyces cerevisiae as a soluble protein. The yeast-expressed enzyme has both N-deacetylase and N-sulfotransferase activities. N-acetyl heparosan, isolated from Escherichia coli K5 polysaccharide, de-N-sulfated heparin (DNSH) and completely desulfated N-acetylated heparan sulfate (CDSNAcHS) are all good substrates for the rNDST-1. However, N-desulfated, N-acetylated heparin (NDSNAcH) is a poor substrate. The rNDST-1 was partially purified on heparin Sepharose CL-6B. Purified rNDST-1 requires Mn(2+) for its enzymatic activity, can utilize PAPS regenerated in vitro by the PAPS cycle (PAP plus para-nitrophenylsulfate in the presence of arylsulfotransferase IV), and with the addition of exogenous PAPS is capable of producing 60-65% N-sulfated heparosan from E. coli K5 polysaccharide or Pasteurella multocida polysaccharide.     

Lithocholic acid extends longevity of chronologically aging yeast only if added at certain critical periods of their lifespan

Our studies revealed that LCA (lithocholic bile acid) extends yeast chronological lifespan if added to growth medium at the time of cell inoculation. We also demonstrated that longevity in chronologically aging yeast is programmed by the level of metabolic capacity and organelle organization that they developed before entering a quiescent state and, thus, that chronological aging in yeast is likely to be the final step of a developmental program progressing through at least one checkpoint prior to entry into quiescence. Here, we investigate how LCA influences longevity and several longevity-defining cellular processes in chronologically aging yeast if added to growth medium at different periods of the lifespan. We found that LCA can extend longevity of yeast under CR (caloric restriction) conditions only if added at either of two lifespan periods. One of them includes logarithmic and diauxic growth phases, whereas the other period exists in early stationary phase. Our findings suggest a mechanism linking the ability of LCA to increase the lifespan of CR yeast only if added at either of the two periods to its differential effects on various longevity-defining processes. In this mechanism, LCA controls these processes at three checkpoints that exist in logarithmic/diauxic, post-diauxic and early stationary phases. We therefore hypothesize that a biomolecular longevity network progresses through a series of checkpoints, at each of which (1) genetic, dietary and pharmacological anti-aging interventions modulate a distinct set of longevity-defining processes comprising the network; and (2) checkpoint-specific master regulators monitor and govern the functional states of these processes.     

Regulation of Epithelial Differentiation in Rat Intestine by Intraluminal Delivery of an Adenoviral Vector or Silencing RNA Coding for Schlafen 3

Although we stimulate enterocytic proliferation to ameliorate short gut syndrome or mucosal atrophy, less effort has been directed at enterocytic differentiation. Schlafen 3 (Slfn3) is a poorly understood protein induced during IEC-6 enterocytic differentiation. We hypothesized that exogenous manipulation of Slfn3 would regulate enterocytic differentiation in vivo. Adenoviral vector coding for Slfn3 cDNA (Ad-GFP-Slfn3) or silencing RNA for Slfn3 (siSlfn3) was introduced intraluminally into rat intestine. We assessed Slfn3, villin, sucrase-isomaltase (SI), Dpp4, and Glut2 by qRT-PCR, Western blot, and immunohistochemistry. We also studied Slfn3 and these differentiation markers in atrophic defunctionalized jejunal mucosa and the crypt-villus axis of normal jejunum. Ad-GFP-Slfn3 but not Ad-GFP increased Slfn3, villin and Dpp4 expression in human Caco-2 intestinal epithelial cells. Injecting Ad-GFP-Slfn3 into rat jejunum in vivo increased mucosal Slfn3 mRNA three days later vs. intraluminal Ad-GFP. This Slfn3 overexpression was associated with increases in all four differentiation markers. Injecting siSlfn3 into rat jejunum in vivo substantially reduced Slfn3 and all four intestinal mucosal differentiation markers three days later, as well as Dpp4 specific activity. Endogenous Slfn3 was reduced in atrophic mucosa from a blind-end Roux-en-Y anastomosis in parallel with differentiation marker expression together with AKT and p38 signaling. Slfn3 was more highly expressed in the villi than the crypts, paralleling Glut2, SI and Dpp4. Slfn3 is a key intracellular regulator of rat enterocytic differentiation. Understanding how Slfn3 works may identify targets to promote enterocytic differentiation and maintain mucosal function in vivo, facilitating enteral nutrition and improving survival in patients with mucosal atrophy or short gut syndrome.     

Polyclonal antibodies against the human cell surface CD34 marker

A highly efficient and inexpensive laboratory method of production and purification of polyclonal antibodies against the human cell surface CD34 marker was developed. It was demonstrated that unglycosy-lated recombinant protein cloned in E. coli cells and containing the extracellular fragment of the human CD34 antigen maintained the necessary antigenic determinants during isolation from bacteria and during immunization, induced the production of specific polyclonal antibodies, which could recognize the native antigen on the cell surface. The obtained antibodies can be used for CD34⁺ cell phenotyping by the immunocytochemistry and flow cytometry methods.