Effect of Feed Restriction on Performance and Postprandial Nutrient Metabolism in Pigs Co-Infected with Mycoplasma hyopneumoniae and Swine Influenza Virus

As nutritional status and inflammation are strongly connected, feeding and nutritional strategies could be effective to improve the ability of pigs to cope with disease. The aims of this study were to investigate the impact of a feed restriction on the ability of pigs to resist and be tolerant to a coinfection with Mycoplasma hyopneumoniae (Mhp) and the European H1N1 swine influenza virus, and the consequences for nutrient metabolism, with a focus on amino acids. Two groups of specific pathogen-free pigs were inoculated with Mhp and H1N1 21 days apart. One group was fed ad libitum, the other group was subjected to a two-week 40% feed restriction starting one week before H1N1 infection. The two respective mock control groups were included. Three days post-H1N1 infection, 200 g of feed was given to pigs previously fasted overnight and serial blood samples were taken over 4 hours to measure plasma nutrient concentrations. Throughout the study, clinical signs were observed and pathogens were detected in nasal swabs and lung tissues. Feed-restricted pigs presented shorter hyperthermia and a positive mean weight gain over the 3 days post-H1N1 infection whereas animals fed ad libitum lost weight. Both infection and feed restriction reduced postprandial glucose concentrations, indicating changes in glucose metabolism. Post-prandial plasma concentrations of the essential amino acids histidine, arginine and threonine were lower in co-infected pigs suggesting a greater use of those amino acids for metabolic purposes associated with the immune response. Altogether, these results indicate that modifying feeding practices could help to prepare animals to overcome an influenza infection. Connections with metabolism changes are discussed.     

Nitroimidazole conjugates of bis(thiosemicarbazonato)Cu(II) - Potential combination agents for the PET imaging of hypoxia

Combination agents comprising two different pharmacophores with the same biological target have the potential to show additive or synergistic activity. Bis(thiosemicarbazonato)copper(II) complexes (e.g. ⁶⁴Cu-ATSM) and nitroimidazoles (e.g. ¹⁸F-MISO) are classes of tracer used for the delineation of tumor hypoxia by positron emission tomography (PET). Three nitroimidazole-bis(thiosemicarbazonato)copper(II) conjugates were produced in order to investigate their potential as combination hypoxia imaging agents. Two were derived from the known bifunctional bis(thiosemicarbazone) H₂ATSM/A and the third from the new precursor diacetyl-2-(4-N-methyl-3-thiosemicarbazone)-3-(4-N-ethylamino-3-thiosemicarbazone) - H₂ATSM/en. Oxygen-dependent uptake studies were performed using the ⁶⁴Cu radiolabelled complexes in EMT6 carcinoma cells. All the complexes displayed appreciable hypoxia selectivity, with the nitroimidazole conjugates displaying greater selectivity than a simple propyl derivative used as a control. Participation of the nitroimidazole group in the trapping mechanism is indicated by the increased hypoxic uptake of the 2- vs. the 4-substituted ⁶⁴Cu-ATSM/A derivatives. The 2-nitroimidazole derivative of ⁶⁴Cu-ATSM/en demonstrated superior hypoxia selectivity to ⁶⁴Cu-ATSM over the range of oxygen concentrations tested. Biodistribution of the radiolabelled 2-nitroimidazole conjugates was carried out in EMT6 tumor-bearing mice. The complexes showed significantly different uptake trends in comparison to each other and previously studied Cu-ATSM derivatives. Uptake of the Cu-ATSM/en conjugate in non-target organs was considerably lower than for derivatives based on Cu-ATSM/A.     

Calculation of effective diffusivities for biofilms and tissues.

In this study we describe a scheme for numerically calculating the effective diffusivity of cellular systems such as biofilms and tissues. This work extends previous studies in which we developed the macroscale representations of the transport equations for cellular systems based on the subcellular-scale transport and reaction processes. A finite-difference model is used to predict the effective diffusivity of a cellular system on the basis of the subcellular-scale geometry and transport parameters. The effective diffusivity is predicted for a complex three-dimensional structure that is based on laboratory observations of a biofilm, and these numerical predictions are compared with predictions from a simple analytical solution and with experimental data. Our results indicate that, under many practical circumstances, the simple analytical solution can be used to provide reasonable estimates of the effective diffusivity.     

Microcalorimetric assay of acetylcholinesterase

Comparative assays were made in a spectrophotometer and a microcalorimeter for the reaction between acetylcholinesterase (EC 3.1.1.7) and acetylthiocholine. The rate of light absorbance change and the rate of heat flow were measured from similar and simultaneous reactions in spectrophotometer and microcalorimeter, respectively. At the enzyme activity levels studied, i.e., 0.05–0.15 I.U. in calorimetry and 1–4 I.U. in spectrophotometry, the reaction rates were linear and showed first-order kinetics. A highly significant positive correlation was seen between the two methods (r = 0.997). More importantly, spectrophotometric assay with acetylthiocholine (which utilized a secondary reaction with chromagen, dithiobisnitrobenzoic acid) stood in highly significant positive correlation with calorimetric assays (which did not require a chromagen) either with the same substrate (r = 0.976) or with acetylcholine (r = 0.900). It appears that microcalorimetry can be used in preference to spectrophotometry for enzyme kinetic studies to overcome the complexity of reaction mixture and interference problems and with the advantage of using natural substrates.     

Identification of a rice RNA- and microtubule-binding protein as the multifunctional protein, a peroxisomal enzyme involved in the beta -oxidation of fatty acids.

The control of subcellular mRNA localization and translation is often mediated by protein factors that are directly or indirectly associated with the cytoskeleton. We report the identification and characterization of a rice seed protein that possesses both RNA and microtubule binding activities. In vitro UV cross-linking assays indicated that this protein binds to all mRNA sequences tested, although there was evidence for preferential binding to RNAs that contained A-C nucleotide sequence motifs. The protein was purified to homogeneity using a two-step procedure, and amino acid sequencing identified it as the multifunctional protein (MFP), a peroxisomal enzyme known to possess a number of activities involved in the beta-oxidation of fatty acids. The recombinant version of this rice MFP binds to RNA in UV cross-linking and gel mobility shift experiments, co-sediments specifically with microtubules, and possesses at least two enzymatic activities involved in peroxisomal fatty acid beta-oxidation. Taken together these data suggest that MFP has an important role in mRNA physiology in the cytoplasm, perhaps in regulating the localization or translation of mRNAs through an interaction with microtubules, in addition to its peroxisomal function.     

Synthesis of 6(α,β)-aminocholestanols as ergosterol biosynthesis inhibitors

Δ⁷-5-Desaturase catalyses one of the last steps in ergosterol biosynthesis in fungi. Moreover Δ⁵-unsaturation is necessary for the sparking function. Synthesis of three pairs of C-6 epimeric cholestanol derivatives are described as potential growth inhibitors. Preliminary results suggest that 6β-aminocholestanol is a potent antifungal agent.     

Sulfhydryl-reagent inhibition of olfaction in a moth and effects of exposure to pheromone compounds or a pheromone analogue

The effects on olfaction of N-ethylmaleimide (NEM), a specificreagent of free sulfhydryl groups, were studied in the mothMamestra brassicae. The antennae of male M.brassicae bear twotypes of specialist receptor neurons involved in pheromone communication.One type is tuned to (Z)-11-hexadecenyl acetate (Z11-16:Ac),the main pheromone component; the second type is tuned to (Z)-9-tetradecenylacetate (Z9-14:Ac), an interspecific inhibitor not producedby the females of this species. Vapours of NEM irreversiblyinhibited the electro-antennographic (EAG) responses to Z11-16:Acand Z9-14:Ac. When Zll-16:Ac was applied before and during NEMtreatment, the responses to Z9-14:Ac were preserved and someprotection was observed in the responses to Zll-16:Ac. In return,Z9-14:Ac partially prevented the disappearance of responsesto Zll-16:Ac but not to Z9-14:Ac. A third compound, hexadecylacetate (16:Ac), found in the pheromone gland, but not detectedby the antennal receptors, did not prevent the inhibition causedby NEM.     

Crystal structure of human PACRG in complex with MEIG1 reveals roles in axoneme formation and tubulin binding

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