Radiated temperature from thermal imaging is related to feed consumption,growth rate and feed efficiency in grower pigs

Individual feed consumption and animal weight were continuously recorded in grower pigs using an automated feeding system. Infrared images were recorded each time a pig entered the feeding system and infrared thermography provided radiated thermal measurements of the dorsal surface of each animal. Feed was withdrawn and the animals fasted for a period of 24 h three times during the growth of the animals at body weights of approximately 35, 65 and 105 kg. There was a significant reduction of 0.28 °C in the maximum surface temperature (Tmax), and 0.48 °C in the average surface temperature (Tmean) during the periods of fasting. Maximum and average pig temperatures exhibited negative correlations to feed consumption and growth variables. There were negative correlations of residual feed intake (RFI) to Tmax and Tmean radiated temperatures. There were positive correlations of residual gain (RG) and residual intake and gain (RIG) with Tmax and Tmean. The Tmax and Tmean temperature responses to fasting were negatively associated with feed consumption and growth variables. Absolute temperature and temperature response variables were positively associated with RFI and negatively associated with residual intake and gain (RIG). These findings provide support for the concept of radiated heat losses as a measure of metabolic activity and a predictor of growth performance.     

Binding of the plant alkaloid aristololactam-β-d-glucoside and antitumor antibiotic daunomycin to single stranded polyribonucleotides

Background

Interaction of the plant alkaloid aristololactam-β-d-glucoside and the antitumor drug daunomycin with single stranded RNAs poly(G), poly(I), poly(C) and poly(U) has been investigated.

Methods

Biophysical techniques of absorption, fluorescence, competition dialysis, circular dichroism, and microcalorimetry have been used.

Results

Absorption and fluorescence studies have revealed noncooperative binding of ADG and DAN to the single stranded RNAs. The binding affinity of ADG varied as poly(G) > poly(I) > > poly(C) > poly(U). The affinity of DAN was one order higher than that of ADG and varied as poly(G) > poly(I) > poly(U) > poly(C). This binding preference was further confirmed by competition dialysis assay. The thermodynamics of the binding was characterised to be favourable entropy and enthalpic terms but their contributions were different for different systems. The major non-polyelectrolytic contribution to the binding revealed from salt dependent data appears to be arising mostly from stacking of DAN and ADG molecules with the bases leading to partial intercalation to single stranded RNA structures. Small negative heat capacity values have been observed in all the four cases.

Conclusions

This study presents the comparative structural and thermodynamic profiles of the binding of aristololactam-β-d-glucoside and daunomycin to single stranded polyribonucleotides.

General significance

These results suggest strong, specific but differential binding of these drug molecules to the single stranded RNAs and highlight the role of their structural differences in the interaction profile.     

Quantum chemical insight on vibration spectra of silica systems

A set of silicate ions and corresponding lithium salts have been quantum chemically (QC) simulated in a “free molecule” approach. The infrared (IR), inelastic neutron scattering (INS), and Raman spectra have been simulated and fitted to the experimentally registered ones. The complete assignment of the vibrational bands along with the intensities and potential energy distribution has been performed. The applicability of the traditionally used quasimolecule Si–O–Si model to the interpretation of bands near 440–480 cm^? 1 and so-called “Boson” peak near 50 cm^? 1 has been critically discussed.     

A Fourier Transform-Raman Spectroscopic Study of Lichen Strategies on Granite Monuments

The biodeterioration of granite by Lecidea fuscoatra (L.) Ach., Porpidia cinereoatra (Ach.) Hertel & Knoph, and P. macrocarpa (DC.) Hertel & Schwab growing in the same environmental conditions has been studied by using Fourier transform-Raman spectroscopy. Results were significantly different for the three species, with P. cinereoatra being the most active biodeteriorative lichen. This lichen was also the only one in which calcium oxalate and gypsum were identified spectroscopically. Physical disturbances to the substratum were evidenced in all lichens studied by the incoporation of material, such as quartz and feldspar, into their thalli, but this phenomenon varied considerably from species to species. The results indicate that lichen species can adopt different strategies and can have different biodeteriorative effects on granite, independently of environmental conditions and substrate.     

Biomineralization of Poorly Crystalline Fe(III) Oxides by Dissimilatory Metal Reducing Bacteria (DMRB)

Dissimilatory metal reducing bacteria (DMRB) catalyze the reduction of Fe(III) to Fe(II) in anoxic soils, sediments, and groundwater. Two-line ferrihydrite is a bioavailable Fe(III) oxide form that is exploited by DMRB as a terminal electron acceptor. A wide variety of biomineralization products result from the interaction of DMRB with 2-line ferrihydrite. Here we describe the state of knowledge on the biotransformation of synthetic 2-line ferrihydrite by laboratory cultures of DMRB using select published data and new experimental results. A facultative DMRB is emphasized ( Shewanella putrefaciens ) upon which most of this work has been performed. Key factors controlling the identity of the secondary mineral suite are evaluated including medium composition, electron donor and acceptor concentrations, ferrihydrite aging/recrystallization status, sorbed ions, and co-associated crystalline Fe(III) oxides. It is shown that crystalline ferric (goethite, hematite, lepidocrocite), ferrous (siderite, vivianite), and mixed valence (magnetite, green rust) iron solids are formed in anoxic, circumneutral DMRB incubations. Some products are well rationalized based on thermodynamic considerations, but others appear to result from kinetic pathways driven by ions that inhibit interfacial electron transfer or the precipitation of select phases. The primary factor controlling the nature of the secondary mineral suite appears to be the Fe(II) supply rate and magnitude, and its surface reaction with the residual oxide and other sorbed ions. The common observation of end-product mineral mixtures that are not at global equilibrium indicates that microenvironments surrounding respiring DMRB cells or the reaction-path trajectory (over Eh-pH space) may influence the identity of the final biomineralization suite.     

Mechanism of Ferrous Iron Binding and Oxidation by Ferritin from a Pennate Diatom

A novel ferritin was recently found in Pseudo-nitzschia multiseries (PmFTN), a marine pennate diatom that plays a major role in global primary production and carbon sequestration into the deep ocean. Crystals of recombinant PmFTN were soaked in iron and zinc solutions, and the structures were solved to 1.65–2.2-Å resolution. Three distinct iron binding sites were identified as determined from anomalous dispersion data from aerobically grown ferrous soaked crystals. Sites A and B comprise the conserved ferroxidase active site, and site C forms a pathway leading toward the central cavity where iron storage occurs. In contrast, crystal structures derived from anaerobically grown and ferrous soaked crystals revealed only one ferrous iron in the active site occupying site A. In the presence of dioxygen, zinc is observed bound to all three sites. Iron oxidation experiments using stopped-flow absorbance spectroscopy revealed an extremely rapid phase corresponding to Fe(II) oxidation at the ferroxidase site, which is saturated after adding 48 ferrous iron to apo-PmFTN (two ferrous iron per subunit), and a much slower phase due to iron core formation. These results suggest an ordered stepwise binding of ferrous iron and dioxygen to the ferroxidase site in preparation for catalysis and a partial mobilization of iron from the site following oxidation.     

Monitoring the Interaction between β2-Microglobulin and the Molecular Chaperone αB-crystallin by NMR and Mass Spectrometry: αB-CRYSTALLIN DISSOCIATES β2-MICROGLOBULIN OLIGOMERS*

The interaction at neutral pH between wild-type and a variant form (R3A) of the amyloid fibril-forming protein β₂-microglobulin (β2m) and the molecular chaperone αB-crystallin was investigated by thioflavin T fluorescence, NMR spectroscopy, and mass spectrometry. Fibril formation of R3Aβ2m was potently prevented by αB-crystallin. αB-crystallin also prevented the unfolding and nonfibrillar aggregation of R3Aβ2m. From analysis of the NMR spectra collected at various R3Aβ2m to αB-crystallin molar subunit ratios, it is concluded that the structured β-sheet core and the apical loops of R3Aβ2m interact in a nonspecific manner with the αB-crystallin. Complementary information was derived from NMR diffusion coefficient measurements of wild-type β2m at a 100-fold concentration excess with respect to αB-crystallin. Mass spectrometry acquired in the native state showed that the onset of wild-type β2m oligomerization was effectively reduced by αB-crystallin. Furthermore, and most importantly, αB-crystallin reversibly dissociated β2m oligomers formed spontaneously in aged samples. These results, coupled with our previous studies, highlight the potent effectiveness of αB-crystallin in preventing β2m aggregation at the various stages of its aggregation pathway. Our findings are highly relevant to the emerging view that molecular chaperone action is intimately involved in the prevention of in vivo amyloid fibril formation.     

Coarse Architecture of the Transient Receptor Potential Vanilloid 1 (TRPV1) Ion Channel Determined by Fluorescence Resonance Energy Transfer

The transient receptor potential vanilloid 1 ion channel is responsible for the perception of high temperatures and low extracellular pH, and it is also involved in the response to some pungent compounds. Importantly, it is also associated with the perception of pain and noxious stimuli. Here, we attempt to discern the molecular organization and location of the N and C termini of the transient receptor potential vanilloid 1 ion channel by measuring FRET between genetically attached enhanced yellow and cyan fluorescent protein to the N or C terminus of the channel protein, expressed in transfected HEK 293 cells or Xenopus laevis oocytes. The static measurements of the domain organization were mapped into an available cryo-electron microscopy density of the channel with good agreement. These measurements also provide novel insights into the organization of terminal domains and their proximity to the plasma membrane.     

A New Way to Degrade Heme: THE MYCOBACTERIUM TUBERCULOSIS ENZYME MhuD CATALYZES HEME DEGRADATION WITHOUT GENERATING CO*?

MhuD is an oxygen-dependent heme-degrading enzyme from Mycobacterium tuberculosis with high sequence similarity (∼45%) to Staphylococcus aureus IsdG and IsdI. Spectroscopic and mutagenesis studies indicate that the catalytically active 1:1 heme-MhuD complex has an active site structure similar to those of IsdG and IsdI, including the nonplanarity (ruffling) of the heme group bound to the enzyme. Distinct from the canonical heme degradation, we have found that the MhuD catalysis does not generate CO. Product analyses by electrospray ionization-MS and NMR show that MhuD cleaves heme at the α-meso position but retains the meso-carbon atom at the cleavage site, which is removed by canonical heme oxygenases. The novel tetrapyrrole product of MhuD, termed “mycobilin,” has an aldehyde group at the cleavage site and a carbonyl group at either the β-meso or the δ-meso position. Consequently, MhuD catalysis does not involve verdoheme, the key intermediate of ring cleavage by canonical heme oxygenase enzymes. Ruffled heme is apparently responsible for the heme degradation mechanism unique to MhuD. In addition, MhuD heme degradation without CO liberation is biologically significant as one of the signals of M. tuberculosis transition to dormancy is mediated by the production of host CO.     

Heme-binding properties of heme detoxification protein from Plasmodium falciparum

The heme detoxification protein of the malaria parasite Plasmodium falciparum is involved in the formation of hemozoin, an insoluble crystalline form of heme. Although the disruption of hemozoin formation is the most widely used strategy for controlling the malaria parasite, the heme-binding properties of heme detoxification protein are poorly characterized. In this study, we established a method for the expression and purification of the non-tagged protein and characterized heme-binding properties. The spectroscopic features of non-tagged protein differ from those of the His-tagged protein, suggesting that the artificial tag interferes with the properties of the recombinant protein. The purified recombinant non-tagged heme detoxification protein had two heme-binding sites and exhibited a spectrum typical of heme proteins. A mechanism for hemozoin formation is proposed.