Role of Peptides in Rumen Microbial Metabolism - Review -

Wallace, R.J.,Atasoglu, C.,Newbold, C.J. Asian Australasian Association of Animal Productio 1999 Animal Bioscience Vol.12 No.1

Peptides are formed in the rumen as the result of microbial proteinase activity. The predominant type of activity is cysteine ptoteinase, but others, such as serine proteinases, are also present. Many species of protozoa, bacteria and fungi are involved in ptoteolysis; large animal-to-animal variability is found when proteinase activities in different animals are compared. The peptides formed from proteolysis are broken down to amino acids by peptidases. Different peptides are broken down at different rates, depending on their chemical composition and particularly their N-terminal structure. Indeed, chemical addition to the N-terminus of small peptides, such as by acetylation, causes the peptides to become stable to breakdown by the rumen microbial population; the microorganisms do not appear to adapt to hydrolyse acetylated peptides even after several weeks exposure to dietary acetylated peptides, and the amino acids present in acetylated peptides are absorbed from the small intestine. The amino acids present in some acetylated peptides remain available in nutritional trials with rats, but the nutritive value of the whole amino acid mixture is decreased by acetylation. The genus Prevotella is responsible for most of the catabolic peptidase activity in the rumen, via its dipeptidyl peptidase activities, which release dipeptides rather than free amino acids from the N-terminus of oligopeptides. Studies with dipeptidyl peptidase mutants of Prevotella suggest that it may be possible to slow the rate of peptide hydrolysis by the mixed rumen microbial population by inhibiting dipeptidyl peptidase activity of Prevotella or the rate of peptide uptake by this genus. Peptides and amino acids also stimulate the growth of rumen microorganisms, and are necessary for optimal growth rates of many species growing on tapidly fermented substrates; in rich medium, most bacteria use pre-formed amino acids for more than 90% of their amino acid requirements. Cellulolytic species are exceptional in this respect, but they still incorporate about half of their cell N from pre-formed amino acids in rich medium. However, the extent to which bacteria use ammonia vs. peptides and amino acids for protein synthesis also depends on the concentrations of each, such that preformed amino acids and peptides are probably used to a much lesser extent in vivo than many in vitro experiments might suggest.

Back to School on Construction Blasting Rules of Thumb Revisited

Wallace, Jerry Korean Society of Explosives and Blasting Engineer 2001 화약발파 Vol.19 No.4

This article was presented by the author at the ISEE\`s 27th Annual Conference on Explosives and Blasting Technique in January, 2001 in Orlando, Florida. This article has been updated from tits original version. The opinions and ideas expressed are not necessarily those of the International Society of Explosives Engineers or the editorial/publishing staff of the Journal of Explosives Engineering. Your esponse in form of letters to editor is encouraged.

Finding a junction partner for candidate solar cell absorbers enargite and bournonite from electronic band and lattice matching

Wallace, Suzanne K.,Butler, Keith T.,Hinuma, Yoyo,Walsh, Aron American Institute of Physics 2019 JOURNAL OF APPLIED PHYSICS - Vol.125 No.5

Revisiting the Aqueous Solutions of Dimethyl Sulfoxide by Spectroscopy in the Mid- and Near-Infrared: Experiments and Car–Parrinello Simulations

Wallace, Victoria M.,Dhumal, Nilesh R.,Zehentbauer, Florian M.,Kim, Hyung J.,Kiefer, Johannes American Chemical Society 2015 The Journal of physical chemistry B Vol.119 No.46

<P>The infrared and near-infrared spectra of the aqueous solutions of dimethyl sulfoxide are revisited. Experimental and computational vibrational spectra are analyzed and compared. The latter are determined as the Fourier transformation of the velocity autocorrelation function of data obtained from Car-Parrinello molecular dynamics simulations. The experimental absorption spectra are deconvolved, and the excess spectra are determined. The two-dimensional excess contour plot provides a means of visualizing and identifying spectral regions and concentration ranges exhibiting nonideal behavior. In the binary mixtures, the analysis of the SO stretching band provides a semiquantitative picture of the formation and dissociation of hydrogen-bonded DMSOwater complexes. A maximum concentration of these clusters is found in the equimolar mixture. At high DMSO concentration, the formation of rather stable 3DMSO:1water complexes is suggested. The formation of 1DMSO:2water clusters, in which the water oxygen atoms interact with the sulfoxide methyl groups, is proposed as a possible reason for the marked depression of the freezing temperature at the eutectic point.</P>

Behavior, Design, and Modeling of Structural Walls and Coupling Beams - Lessons from Recent Laboratory Tests and Earthquakes

Wallace, John W. Korea Concrete Institute 2012 International Journal of Concrete Structures and M Vol.6 No.1

Observed wall damage in recent earthquakes in Chile and New Zealand, where modern building codes exist, exceeded expectations. In these earthquakes, structural wall damage included boundary crushing, reinforcement fracture, and global wall buckling. Recent laboratory tests also have demonstrated inadequate performance in some cases, indicating a need to review code provisions, identify shortcomings and make necessary revisions. Current modeling approaches used for slender structural walls adequately capture nonlinear flexural behavior; however, strength loss due to buckling of reinforcement and nonlinear and shear-flexure interaction are not adequately captured. Additional research is needed to address these issues. Recent tests of reinforced concrete coupling beams indicate that diagonally-reinforced beams detailed according to ACI 318-$11^1$ can sustain plastic rotations of about 6% prior to significant strength loss and that relatively simple modeling approaches in commercially available computer programs are capable of capturing the observed responses. Tests of conventionally-reinforced beams indicate less energy dissipation capacity and strength loss at approximately 4% rotation.

Recent Factors for and Against Change in Eastern Europe

WALLACE, WILLIAM V. 동국대학교 유럽연구소 1985 유럽硏究 Vol.3 No.-

Investigating Antecedents of Instagram Attachment and Intention to Post Photos on Instagram

Wallace, Racheal Zara,Jun, Soo-Hyun World Association for Triple Helix and Future Stra 2019 Journal of Contemporary Eastern Asia Vol.18 No.1

This study examined effects of the social-psychological motivations to use Instagram (i.e., identity seeking, social interaction) and narcissistic personality on personal attachment to Instagram and intention to post photos on Instagram. Identity seeking, social interaction and narcissistic personality (i.e., grandiose/exhibition) had significant positive effects on personal attachment to Instagram. Identity seeking and social interaction had significant positive effects on intention to post photos on Instagram. However, narcissistic personality had no effect on the intention to post photos on Instagram. The study results support the theory of the extended-self in the digital context. This study also provides useful information to help organizations understand why people use Instagram as well as how to take advantage of Instagram to enhance their services and consumer experiences.

Putting Function into Fashion: Organic Conducting Polymer Fibres and Textiles

Wallace, G.G.,Campbell, T.E.,Innis, P.C. The Korean Fiber Society 2007 Fibers and polymers Vol.8 No.2

Textiles have traditionally been employed over the centuries with great utility in areas as diverse as fashion through to technical textiles. In all these instances the textile itself has been a structural element that once fabricated has limited utility beyond the intended structural and aesthetic application. In recent years there has been a shift towards the incorporation of electronic systems into textile structures. The new paradigm for textiles is the development of systems that not only provide the more traditional aspects of textiles but expands upon this to provide a unique capability to transmit and store information and energy. More importantly these next generation materials will be capable of responding to external stimuli, modifying features of the textile in a direct response to its working environment. A potential route to truly functional electronic textiles is through the application of conducting polymers.

SOME OBSERVATIONS ON THE SUSCEPTIBILITY OF PEPTIDES TO DEGRADATION BY RUMEN MICROORGANISMS

Wallace, R.J.,McKain, N. Asian Australasian Association of Animal Productio 1989 Animal Bioscience Vol.2 No.3

Increasing the Flow of Protein from Ruminal Fermentation - Review -

Wallace, R.J.,Newbold, C.J.,Bequette, B.J.,MacRae, J.C.,Lobley, G.E. Asian Australasian Association of Animal Productio 2001 Animal Bioscience Vol.14 No.6

This review summarizes some recent research into ways of improving the productivity of ruminal fermentation by increasing protein flow from the rumen and decreasing the breakdown of protein that results from the action of ruminal microorganisms. Proteinases derived from the plant seem to be of importance to the overall process of proteolysis in grazing animals. Thus, altering the expression of proteinases in grasses may be a way of improving their nutritive value for ruminants. Inhibiting rumen microbial activity in ammonia formation remains an important objective: new ways of inhibiting peptide and amino acid breakdown are described. Rumen protozoa cause much of the bacterial protein turnover which occurs in the rumen. The major impact of defaunation on N recycling in the sheep rumen is described. Alternatively, if the efficiency of microbial protein synthesis can be increased by judicious addition of certain individual amino acids, protein flow from ruminal fermentation may be increased. Proline may be a key amino acid for non-cellulolytic bacteria, while phenylalanine is important for cellulolytic species. Inhibiting rumen wall tissue breakdown appears to be an important mechanism by which the antibiotic, flavomycin, improves N retention in ruminants. A role for Fusobacterium necrophorum seems likely, and alternative methods for its regulation are required, since growth-promoting antibiotics will soon be banned in many countries.