Effects of liquid metabolite combinations produced by Lactobacillus plantarum on growth performance, faeces characteristics, intestinal morphology and diarrhoea incidence in postweaning piglets

A study was carried out to investigate the effects of feeding liquid metabolite combinations produced by Lactobacillus plantarum strains on growth performance, diarrhoea incidence, faecal pH, microfloral counts, short-chain fatty acids (SCFA) and intestinal villus height and crypt depth of postweaning piglets. A total of 120 piglets (26 days old) were randomly assigned evenly into five treatment groups treated with same basal diet: (1) −ve control (free antibiotic); (2) + ve control (0.03% of chlortetracycline); (3) Com 1 (0.3% metabolite of TL1, RG11 and RI11 strains); (4) Com 2 (0.3% metabolite of TL1, RG14 and RS5 strains); (5) Com 3 (0.3% metabolite of RG11, RG14 and RI11 strains). After 5 weeks, the average daily feed intake was not significantly different (P > 0.05) among the treatments and feed conversion ratio was the highest (P < 0.05) in the −ve control group. In addition, diarrhoea incidence was reduced when piglets were fed with metabolite combinations. Faecal lactic acid bacteria (LAB) counts were significantly higher (P < 0.05) in metabolite treatment groups than in the groups without metabolites. However, the treatment of Com 2 metabolite resulted lower (P < 0.05) faecal pH and Enterobacteriaceae (ENT) than the −ve control group. In contrast, total faecal SCFA of Com 2 were significantly higher (P < 0.05) than the −ve control group. The villus height of duodenum was higher (P < 0.05) in the + ve control and Com 2 groups as compared to −ve control group. The results obtained in this study showed that feeding metabolite combinations could improve growth performance, and increase the population of gut LAB and faecal SCFA of postweaning piglets

The effects of irisin on the rat thoracic aorta: histological study

Irisin, a polypeptide hormone that is released from skeletal muscle in response to exercise found to improve endothelial functions, protect against endothelial injuries and change blood pressure which also affected blood vessels. The aim of this study is to study the histological changes of the rat thoracic aorta in response to irisin injection. Thirty rats were used. Then divided into two groups; the control group without irisin injection, and the irisin injected group was subdivided into four subgroups with different irisin concentrations (20, 40 and 160 nM, respectively) twice a week for four weeks, the control group and each subgroup consisted of 6 rats each. After 4 weeks all rats were sacrificed, and the descending thoracic aorta was treated for histological evaluation. Sections were stained with Hematoxylin and Eosin (H and E) and orcein stains. Morphometric measurement included: intima-media thickness (IMT), number of elastic lamellae and number of smooth muscle cells nuclei. Histological study has shown that intraperitoneal injection of different concentrations of irisin (20, 40 and 160 nM) in rats has increased intima-media thickness, number of smooth muscle cell’s nuclei, and increase the number of elastic lamellae in media layer of the thoracic aorta in a dose dependent manner. Irisin has significantly affected the morphology of the wall of the rat thoracic aorta indicating a role for irisin in influencing the growth factors of the thoracic aorta walls and activate smooth muscle cells in the thoracic aorta layers

Unsupported electrospun membrane for water desalination using direct contact membrane distillation

In this project, an unsupported electrospun poly(vinylidene fluoride)-co-hexafluoropropylene (PVDF-HFP) membrane was used for water desalination using direct contact membrane distillation (DCMD). The membrane was electrospun using a laboratory-scale machine with multiple nozzles that was developed in-house. Critical process parameters, including the applied voltage and polymer concentration, were optimized to obtain bead-free electrospun membranes with fiber diameters less than 300 nm. To improve the membrane thermal stability and performance, the selected electrospun membrane was heat-pressed at 160°C. The untreated and heat-pressed membranes were tested in a DCMD setup at different feed temperatures (60, 70, and 80°C) and feed flow rates (0.4, 0.6, and 0.8 L/min), while maintaining the permeate temperature and flow rate at 20°C and 0.2 L/min, respectively. The modified electrospun membrane exhibited a very high permeate flux (>37.5 kg/m2/h) and a salt rejection rate of 99.99% at a feed temperature of 70°C. The performance of the heat-pressed unsupported PVDF-HFP electrospun membrane was nearly identical to a commercially available polytetrafluoroethylene (PTFE) supported membrane. These promising results demonstrate that relatively low-cost electrospun membranes can be easily produced and successfully used in DCMD to minimize the capital cost and increase the energy efficiency of the process.Peer reviewe

Carboxyl Group of Glu113 Is Required for Stabilization of the Diferrous and Bis-Fe IV

The diheme enzyme MauG catalyzes a six-electron oxidation required for posttranslational modification of a precursor of methylamine dehydrogenase (preMADH) to complete the biosynthesis of its protein-derived tryptophan tryptophylquinone (TTQ) cofactor. Crystallographic studies have implicated Glu113 in the formation of the bis-Fe(IV) state of MauG, in which one heme is Fe(IV)=O and the other is Fe(IV) with His-Tyr axial ligation. An E113Q mutation had no effect on the structure of MauG, but significantly altered its redox properties. E113Q MauG could not be converted to the diferrous state by reduction with dithionite, but was only reduced to a mixed valence Fe(II)/Fe(III) state, which is never observed in wild-type (WT) MauG. Addition of H(2)O(2) to E113Q MauG generated a high valence state that formed more slowly and was less stable than the bis-Fe(IV) state of WT MauG. E113Q MauG exhibited no detectable TTQ biosynthesis activity in a steady-state assay with preMADH as the substrate. It did catalyze the steady-state oxidation of quinol MADH to the quinone, but 1000-fold less efficiently than WT MauG. Addition of H(2)O(2) to a crystal of the E113Q MauG-preMADH complex resulted in partial synthesis of TTQ. Extended exposure of these crystals to H(2)O(2) resulted in hydroxylation of Pro107 in the distal pocket of the high-spin heme. It is concluded that the loss of the carboxylic group of Glu113 disrupts the redox cooperativity between hemes that allows rapid formation of the diferrous state, and alters the distribution of high-valence species that participate in charge-resonance stabilization of the bis-Fe(IV) redox state

Competitive adsorption of Alizarin Red S and Bromocresol Green from aqueous solutions using brookite TiO2 nanoparticles: experimental and molecular dynamics simulation

In this work, the effective adsorption and the subsequent photodegradation activity, of TiO2 brookite nanoparticles, for the removal of anionic dyes, namely, Alizarin Red S (ARS) and Bromocresol Green (BCG) were studied. Batch adsorption experiments were conducted to investigate the effect of both dyes' concentration, contact time, and temperature. Photodegradation experiments for the adsorbed dyes were achieved using ultraviolet light illumination (6&nbsp;W, λ = 365&nbsp;nm). The single adsorption isotherms were fitted to the Sips model. The binary adsorption isotherms were fitted using the Extended-Sips model. The results of adsorption isotherms showed that the estimated maximum adsorption uptakes in the binary system were around 140&nbsp;mg&nbsp;g-1 and 45.5&nbsp;mg&nbsp;g-1 for ARS and BCG, respectively. In terms of adsorption kinetics, the uptake toward ARS was faster than BCG molecules in which the equilibrium was obtained in 7&nbsp;min for ARS, while it took 180&nbsp;min for BCG. Moreover, the thermodynamics results showed that the adsorption process was spontaneous for both anionic dyes. All these macroscopic competitive adsorption results indicate high selectivity toward ARS molecules in the presence of BCG molecules. Additionally, the TiO2 nanoparticles were successfully regenerated using UV irradiation. Moreover, molecular dynamics computational modeling was performed to understand the molecules' optimum coordination, TiO2 geometry, adsorption selectivity, and binary solution adsorption energies. The simulation energies distribution exhibits lower adsorption energies for ARS in the range from - 628 to - 1046 [Formula: see text] for both single and binary systems. In addition to that, the water adsorption energy was found to be between - 42 and - 209 [Formula: see text]

Characterization of Electron Tunneling and Hole Hopping Reactions between Different Forms of MauG and Methylamine Dehydrogenase within a Natural Protein Complex

Respiration, photosynthesis and metabolism require the transfer of electrons through and between proteins over relatively long distances. It is critical that this electron transfer (ET) occur with specificity to avoid cellular damage, and at a rate which is sufficient to support the biological activity. A multi-step hole hopping mechanism could, in principle, enhance the efficiency of long range ET through proteins as it does in organic semiconductors. To explore this possibility, two different ET reactions that occur over the same distance within the protein complex of the diheme enzyme MauG and different forms of methylamine dehydrogenase (MADH) were subjected to kinetic and thermodynamic analysis. An ET mechanism of single-step direct electron tunneling from diferrous MauG to the quinone form of MADH is consistent with the data. In contrast, the biosynthetic ET from preMADH, which contains incompletely synthesized tryptophan tryptophylquinone, to the bis-Fe(IV) form of MauG is best described by a two-step hole hopping mechanism. Experimentally-determined values of ET distance matched the distances determined from the crystal structure that would be expected for single-step tunneling and multi-step hopping, respectively. Experimentally-determined relative values of electronic coupling (H(AB)) for the two reactions correlated well with the relative H(AB) values predicted from computational analysis of the structure. The rate of the hopping-mediated ET reaction is also ten-fold greater than that of the single-step tunneling reaction despite having a smaller overall driving force for the reaction. These data provide insight into how the intervening protein matrix and redox potentials of the electron donor and acceptor determine whether the ET reaction proceeds via single-step tunneling or multi-step hopping

Oxidative Damage in MauG: Implications for the Control of High-Valent Iron Species and Radical Propagation Pathways

The di-heme enzyme MauG catalyzes the oxidative biosynthesis of a tryptophan tryptophylquinone (TTQ) cofactor on a precursor of the enzyme methylamine dehydrogenase (preMADH). Reaction of H(2)O(2) with the diferric form of MauG, or reaction of O(2) with diferrous MauG, forms the catalytic intermediate known as bis-Fe(IV), which acts as the key oxidant during turnover. The site of substrate oxidation is over 40 A from the high-spin heme iron where H(2)O(2) initially reacts, and catalysis relies on radical hopping through an interfacial residue, MauG Trp199. In the absence of preMADH, the bis-Fe(IV) intermediate is remarkably stable, but repeated exposure to H(2)O(2) results in suicide inactivation. Using mass spectrometry, we show that this process involves the oxidation of three Met residues (108, 114 and 116) near the high-spin heme through ancillary electron transfer pathways engaged in the absence of substrate. The mutation of a conserved Pro107 in the distal pocket of the high-spin heme results in a dramatic increase in oxidation of these Met residues. These results illustrate structural mechanisms by which MauG controls reaction with its high-valent heme cofactor and limits uncontrolled oxidation of protein residues and loss of catalytic activity. The conservation of Met residues near the high-spin heme among MauG homologues from different organisms suggests that eventual deactivation of MauG may function in a biological context. That is, methionine oxidation may represent a protective mechanism that prevents the generation of reactive oxygen species by MauG in the absence of preMADH