Digestibility of phosphorous in cereals and co-products for animal feed

Feed ingredients used in swine diets contain various levels and availabilities of nutrients. Nutritional precision evaluation of each ingredient is necessary for formulating diets of pigs. Especially, phosphorous (P) is one of important nutrients for metabolism. However, current data of P digestibility were most apparent digestibility. Therefore, this study was aimed to estimate the coefficient of total tract standardized digestibility (CTTSD) of P in cereals and various co-products used in pig diet. Twelve barrows (initial BW?±?SD, 46.70?±?3.21?kg) were used in this experiment. The experimental design was a 12?×?8 incomplete Latin square with 12 diets and 8 periods. Experimental diets were consisted of barley, wheat, lupine kernel (LK), soybean meal (SBM), almond meal (AM), corn gluten meal (CGM), corn gluten feed from China (CGF-C), corn gluten feed from Korea (CGF-C), wheat bran (WB), rice bran (RB), lupine hull (LH) and P-free diet. The CTTAD of Ca was higher in AM than RB and CGF-K. The LK and CGM showed greater CTTSD of P than RB and LH. In conclusion, our results indicated that the cereals and co-products as P sources were the ideally used as an ingredient in mixed diets of the growing-finishing pigs.     

Purification,characterization and cloning of aldehyde dehydrogenase from <Emphasis Type="Italic">Rhodococcus erythropolis</Emphasis> UPV-1

The enzyme responsible for formaldehyde removal in industrial wastewaters by cells of Rhodococcus erythropolis UPV-1 was identified as a broad-specific aldehyde dehydrogenase (EC 1.2.1.3). The enzyme was purified to electrophoretic homogeneity from ethanol-grown cells with a specific activity of 19.5 U mg⁻¹ protein and an activity recovery of 56%. The enzyme showed an isoelectric point (pI) of 5.3 and was a trimer of 162 kDa consisting of three identical 54-kDa subunits. It was specific for NAD⁺ and showed hyperbolic kinetics for this coenzyme (K _m=90 μM), but sigmoidal kinetics for the aliphatic aldehydes used as substrates. The enzyme affinity for aldehydes increased with their hydrocarbon chain length, ranging from 333 μM for formaldehyde to 85 nM for n-octanal. The corresponding calculated Hill coefficients were in the 1.55–2.77 range. With n-propanal as substrate, the optimum pH and temperature for activity were 9.5–10.0 and 47.5°C, respectively, with an E _a for catalysis of 28.6 kJ mol⁻¹. NAD⁺ protected the enzyme against thermal inactivation, but aldehydes were ineffective. The activity was severely inhibited by p-hydroxymercuribenzoate, indicating that a thiol was essential for catalysis. The 1,524-bp aldhR gene encoding a 507-amino-acid protein was expressed in cells of Escherichia coli M15 as a hexahistidine-tagged protein.     

Differential estradiol requirement for the induction of estrus behavior and the luteinizing hormone surge in two breeds of sheep

For a better understanding of the mechanisms that lead to the preovulatory GnRH/LH surge and estrus behavior, the minimum estradiol (E) requirements (dose and duration) to induce each of these events were determined and compared between two breeds of ewes having either single (Ile de France) or multiple (Romanov) ovulations. The ewes were initially studied during a natural estrus cycle, and were then ovariectomized and run through successive artificial estrus cycles. For these artificial cycles the duration and amplitude of the follucular phase E increase were manipulated by E implants. Under all conditions, the onset of estrus behavior was similar in the two breeds, although its duration was longer in Romanov ewes. While a moderate E signal (6 cm for 12 h) induced an LH surge in 10/10 Ile de France ewes, a larger E signal (12 cm for 12 h) was minimally effective in Romanov ewes (4/10). Additional studies revealed that a small E signal (3 cm for 6 h) induced full estrus behavior in all Romanov ewes but was completely ineffective in Ile de France animals (0/10). Higher doses and mostly longer durations of the E signal (12 cm for 24 h) were required to induce a surge in all the Romanov ewes. These results demonstrate a clear difference in the E requirement for the induction of estrus behavior and the LH surge between breeds of ewes that have different ovulation rates. These data provide compelling evidence that, in one breed, the neuronal systems that regulate both events require different estrogen signals.     

Efficient splicing correction by PNA conjugation to an R6-Penetratin delivery peptide

Sequence-specific interference with the nuclear pre-mRNA splicing machinery has received increased attention as an analytical tool and for development of therapeutics. It requires sequence-specific and high affinity binding of RNaseH-incompetent DNA mimics to pre-mRNA. Peptide nucleic acids (PNA) or phosphoramidate morpholino oligonucleotides (PMO) are particularly suited as steric block oligonucleotides in this respect. However, splicing correction by PNA or PMO conjugated to cell penetrating peptides (CPP), such as Tat or Penetratin, has required high concentrations (5–10μM) of such conjugates, unless an endosomolytic agent was added to increase escape from endocytic vesicles. We have focused on the modification of existing CPPs to search for peptides able to deliver more efficiently splice correcting PNA or PMO to the nucleus in the absence of endosomolytic agents. We describe here R₆-Penetratin (in which arginine-residues were added to the N-terminus of Penetratin) as the most active of all CPPs tested so far in a splicing correction assay in which masking of a cryptic splice site allows expression of a luciferase reporter gene. Efficient and sequence-specific correction occurs at 1μM concentration of the R6Pen–PNA705 conjugate as monitored by luciferase luminescence and by RT-PCR. Some aspects of the R6Pen–PNA705 structure–function relationship have also been evaluated.     

Parasympathetic reactivation after repeated sprint exercise

The purpose of this study was to examine the effects of muscular power engagement, anaerobic participation, aerobic power level, and energy expenditure on postexercise parasympathetic reactivation. We compared the response of heart rate (HR) after repeated sprinting with that of exercise sessions of comparable net energy expenditure and anaerobic energy contribution. Fifteen moderately trained athletes performed 1) 18 maximal all-out 15-m sprints interspersed with 17 s of passive recovery (RS), 2) a moderate isocaloric continuous exercise session (MC) at a level of mean oxygen uptake similar to that of the RS trial, and 3) a high-intensity intermittent exercise session (HI) conducted at a level of anaerobic energy expenditure similar to that of the RS trial. Subjects were immediately seated after the exercise trials, and beat-to-beat HR was recorded for 10 min. Parasympathetic reactivation was evaluated through 1) immediate postexercise HR recovery, 2) the time course of the root mean square for the successive R-R interval difference between successive 30-s segments (RMSSD(30s)) and 3) HR variability vagal-related indexes calculated for the last 5-min stationary period of recovery. RMSSD(30s) increased during the 10-min period after the MC trial, whereas RMSSD(30s) remained depressed after both the RS and HI trials. Parasympathetic reactivation indexes were similar for the RS and HI trials but lower than for the MC trial (P < 0.001). When data of the three exercise trials were considered together, only anaerobic contribution was related to HR trial-derived indexes. Parasympathetic reactivation is highly impaired after RS exercise and appears to be mainly related to anaerobic process participation.     

RNA recognition and cleavage by sequence-specific endoribonucleases

Inactivation of RNA molecules by sequence-specific endoribonucleolytic cleavage is a subtle mechanism by which cells regulate gene expression. Sequence-specific endoribonucleases can recognize and cleave particular phosphodiester bonds confined within hundreds/thousands of chemically similar bonds. Here, we present a comparative analysis of the mechanisms used by endoribonucleases to select and cleave their target RNA molecules. This analysis is based on the very recent molecular details obtained from the structural and/or biochemical studies of nine sequence-specific ribonucleases that target messenger, ribosomal, and transfer RNA molecules. This analysis shows that despite the absence of sequence homologies and the wide diversity of biological sources (prokaryotes, archaea and eukaryotes), the sequence-specific ribonucleases studied here adopt limited structural folds, catalyze their cleavage reactions using a common chemistry and involve a very limited set of amino acids for both RNA binding and processing.     

Amperometric and impedimetric characterization of a glutamate biosensor based on Nafion and a methyl viologen modified glassy carbon electrode

An electrochemical biosensor based on a glassy carbon (GC) electrode chemically modified with the perfluorinated cation-exchange polymer Nafion and methyl viologen (MV) is described. The enzyme was immobilized by cross-linking with glutaraldehyde in the presence of bovine serum albumin (BSA), methyl viologen and Nafion. Operating variables such as the enzyme/BSA ratio, cross-linking time in glutaraldehyde vapor, methyl viologen and Nafion percentages were investigated with regard to their influence on the biosensor sensitivity by using glucose oxidase as the enzyme model due to its high stability and low cost. The glutamate biosensor was elaborated by using optimized parameters and its electrochemical properties were investigated by cyclic voltammetry, amperometry and by electrochemical impedance spectroscopy. The glutamate biosensor shows a detection limit of 20 microM and a linear range extended to 0.75 mM. Its selectivity was tested with 15 different amino acids, each with a concentration of 20 microM, 25 microM acetaminophen, 20 microM uric acid and 200 microM ascorbic acid. No amperometric response was observed for the interfering species. This good selectivity allows glutamate detection in biological media without previous separation of the analyte.     

Production and quality of conidia by <Emphasis Type="Italic">Metarhizium anisopliae</Emphasis> var. <Emphasis Type="Italic">lepidiotum</Emphasis>: critical oxygen level and period of mycelium competence

Mycoinsecticides application within Integral Pest Management requires high quantities of conidia, with the proper quality and resistance against environmental conditions. Metarhizium anisopliae var. lepidiotum conidia were produced in normal atmospheric conditions (21 % O₂) and different concentrations of oxygen pulses (16, 26, 30, and 40 %); conidia obtained under hypoxic conditions showed significantly lower viability, hydrophobicity, and virulence against Tenebrio molitor larvae or mealworm, compared with those obtained under normal atmospheric conditions. Higher concentrations of oxygen (26 and 30 %) improved conidial production. However, when a 30 % oxygen concentration was applied, maximal conidial yields were obtained at earlier times (132 h) relative to 26 % oxygen pulses (156 h); additionally, with 30 % oxygen pulses, conidia thermotolerance was improved, maintaining viability, hydrophobicity, and virulence. Although conidial production was not affected when 40 % oxygen pulses were applied, viability and virulence were diminished in those conidia. In order to find a critical time for mycelia competence to respond to these oxidant conditions, oxygen pulses were first applied either at 36, 48, 60, and 72 h. A critical time of 60 h was determined to be the best time for the M. anisopliae var. lepidiotum mycelia to respond to oxygen pulses in order to increase conidial production and also to maintain the quality features. Therefore, oxygen-enriched (30 %) pulses starting at 60 h are recommended for a high production without the impairment of quality of M. anisopliae var. lepidiotum conidia.