scholarly journals Acetylation of peptides inhibits their degradation by rumen micro-organisms

1992 ◽  
Vol 68 (2) ◽  
pp. 365-372 ◽  
Author(s):  
R. J. Wallace
Keyword(s):  
Rumen Fluid ◽  
Inhibitory Effect ◽  
Peptidase Activity ◽  
Ammonia Production ◽  
Terminal Amino ◽  
Sheep Rumen ◽  
A Minor ◽  
Micro Organisms ◽  
Proteins And Peptides

Proteins and peptides were acetylated using acetic anhydride in order to block their N-terminal amino groups and thereby to prevent their hydrolysis by rumen microbial aminopeptidases. The effects of acetylation on peptide breakdown and ammonia production were determined by incubating unmodified and acetylated substrates with sheep rumen micro-organisms in vitro. Ammonia production from casein and lactalbumin was affected little by acetylation, but acetylation of the corresponding enzymic hydrolysates caused ammonia production to be more than halved after 3.6 h incubation. Estimation of peptides remaining in rumen fluid showed that the decreased ammonia production was a consequence of peptides being hydrolysed more slowly. Acetylated Ala-Ala, Ala-Ala-Ala (Ala3), Leu-Gly-Gly, Phe-Gly-Gly and Val-Gly-Ser-Glu survived incubation with rumen fluid in vitro for 6 h, whereas almost none of the corresponding unmodified peptides was present at 6 h. The protection afforded to larger pure peptides was less reliable: for example, 72% of acetylated bradykinin was hydrolysed after 1 h.N-Acetyl Ala3had only a minor inhibitory effect on the breakdown of Ala3and Ala4, suggesting that although acetyl peptides were broken down more slowly than unmodified peptides they did not inhibit peptidase activity.

Repeatability of in vitro digestibility assays of forages when using fresh, frozen or freeze-dried cow faeces instead of sheep rumen liquor as sources of micro-organisms

1995 ◽  
Vol 1995 ◽  
pp. 110-110 ◽  
Author(s):  
S Akhter ◽  
E Owen ◽  
M K Theodorou ◽  
S L Tembo ◽  
E R Deaville
Keyword(s):  
Freeze Drying ◽  
Rumen Fluid ◽  
In Vitro Digestibility ◽  
Two Stage ◽  
Freeze Dried ◽  
Fresh Frozen ◽  
Sheep Rumen ◽  
Micro Organisms

Previous studies (El Shaer, Omed and Axford, 1987; Akhter, Owen, Fall, O'Donovan and Theodorou, 1994) with the two-stage in vitro procedure of Tilley and Terry (1963) have shown a high correlation between digestibilities of forages as determined using either sheep rumen liquor, sheep faeces or cow faeces as the microbial inoculum. In the first study of the of the present investigation one objective was to examine the repeatability of these digestibility measurements when made on different occasions. A second objective was to assess whether the correlations between faecal and rumen fluid based inocula could be improved if microorganisms were obtained from pairs rather than individual animals. The objective in the second study using forages of known in vivo digestibility, was to investigate the effect of freezing or freeze-drying of faeces on the repeatability of digestibilities of forages determined in vitro using micro-organisms from cow faeces.

scholarly journals A comparative study of ruminal activity in Churra and Merino sheep offered alfalfa hay

1997 ◽  
Vol 65 (1) ◽  
pp. 121-128 ◽  
Author(s):  
M. J. Ranilla ◽  
M. D. Carro ◽  
C. Valdés ◽  
F. J. Giráldez ◽  
S. López
Keyword(s):  
Cell Wall ◽  
Rumen Fluid ◽  
Merino Sheep ◽  
Rumen Ph ◽  
Sheep Rumen ◽  
Fermentation Parameters ◽  
Micro Organisms ◽  
Kinetics Of

AbstractA study was carried out to compare the fermentation parameters and kinetics of digestion of a range of different foods in the rumen of two breeds of sheep (Churra and Merino). Ten mature sheep (five Churra and five Merino), each fitted with a rumen cannula, were used in this study. In situ rumen degradability of both dry matter (DM) and cell wall was greater in Churra than in Merino sheep, the breed differences being significant for most of the foods used in the study (P < 0·05). These differences were greater when the foods had a higher cell wall concentration and this could be related to differences in the ruminal environment. However, when the foods were incubated with rumen fluid their in vitro organic matter (OM) degradability was similar in both breeds. Rumen pH was higher (P < 0·05) and ammonia concentrations were lower (P < 0·05) in Churra than in Merino sheep. Rumen volatile fatty acid concentrations tended to be higher in Merino than in Churra sheep, though differences were only significant just before feeding (P < 0·05). The ratio acetate: propionate was higher in the Churra than Merino breed before and 12 h after feeding (P < 0·05). Protozoa numbers in rumen liquid were similar for both genotypes. The greater degradation of forages in the rumen of Churra sheep is discussed in relation to the possible higher activity of fibre-degrading micro-organisms and the greater buffering capacity of the rumen contents against fermentation acids, which could result in more favourable conditions for the microbial degradation of foods in the rumen.

scholarly journals Hydrolysis of14C-labelled proteins by rumen micro-organisms and by proteolytic enzymes prepared from rumen bacteria

1983 ◽  
Vol 50 (2) ◽  
pp. 345-355 ◽  
Author(s):  
R. J. Wallace
Keyword(s):  
Proteolytic Enzymes ◽  
Rumen Fluid ◽  
Performic Acid ◽  
Cross Linking ◽  
Acid Oxidation ◽  
Rumen Bacteria ◽  
Rate Of Hydrolysis ◽  
Micro Organisms ◽  
Hydrolysis Of

1. Proteins were labelled with14C in a limited reductive methylation using [14C]formaldehyde and sodium borohydride.2. The rate of hydrolysis of purified proteins was little (< 10%) affected by methylation and the14C-labelled digestion products were not incorporated into microbial protein during a 5 h incubation with rumen fluid in vitro. It was therefore concluded that proteins labelled with14C in this way are valid substrates for study with rumen micro-organisms.3. The patterns of digestion of14C-labelled fish meal, linseed meal and groundnut-protein meal by rumen micro-organisms in vitro were similar to those found in vivo.4. The rates of hydrolysis of a number of14C-labelled proteins, including glycoprotein II and lectin from kidney beans (Phaseolus vulgaris), were determined with mixed rumen micro-organisms and with proteases extracted from rumen bacteria. Different soluble proteins were digested at quite different rates, with casein being most readily hydrolysed.5. Proteins modified by performic acid oxidation, by cross-linking using 1,6-di-iso-cyanatohexane or by diazotization were labelled with14C. Performic acid treatment generally increased the susceptibility of proteins to digestion, so that the rates of hydrolysis of performic acid-treated proteins were more comparable than those of the unmodified proteins. Cross-linking resulted in a decreased rate of hydrolysis except with the insoluble proteins, hide powder azure and elastin congo red. Diazotization had little effect on the rate of hydrolysis of lactoglobulin and albumin, but inhibited casein hydrolysis and stimulated the breakdown of γ-globulin.

Evaluating the In Vitro Metabolism of Docosahexaenoic Acid in Sheep Rumen Fluid

Lipids ◽  
2012 ◽  
Vol 47 (8) ◽  
pp. 821-825 ◽  
Author(s):  
Noelia Aldai ◽  
Gonzalo Hervás ◽  
Álvaro Belenguer ◽  
Pilar Frutos ◽  
Angel R. Mantecón ◽  
...  
Keyword(s):  
Docosahexaenoic Acid ◽  
Rumen Fluid ◽  
In Vitro Metabolism ◽  
Sheep Rumen

scholarly journals Digestion of grass lipids and pigments in the sheep rumen

1974 ◽  
Vol 32 (2) ◽  
pp. 327-340 ◽  
Author(s):  
R. M. C. Dawson ◽  
Norma Hemington
Keyword(s):  
Small Proportion ◽  
Polar Compounds ◽  
The Other ◽  
Chlorophyll Pigments ◽  
Rapid Decomposition ◽  
Other Hand ◽  
Sheep Rumen ◽  
Micro Organisms

1. Digestion of grass lipids and pigments in the rumen of the sheep has been studied during starvation and following the administration of 14C-labelled grass.2. Both galactolipids contained in chloroplasts are rapidly degraded, although mono-galactosyldiglycerides disappear faster than digalactosyldiglycerides. It was concluded that rumen micro-organisms are mainly responsible for this degradation, although grass itself also contains enzymes which can degrade galactolipids.3. Rumen contents can degrade added 14C-labelled mono- and digalactosyldiglycerides in vitro at a rate sufficient to account for the disappearance of galactolipids in the intact rumen. The initial enzyme attack is probably a successive deacylation to give monogalactosylglycerol and digalactosylglycerol.4. Most of the chlorophyll pigments are rapidly converted into phaeophytins by loss of magnesium. A small proportion of chlorophyll a and more of chlorophyll b remains intact even after 24 h starvation. On the other hand, about half the phaeophytin undergoes further rapid decomposition to yield phylloerythrin.5. Although the grass phospholipids are extensively degraded, β-carotenes and many non-polar compounds, e.g. steroids, appear to undergo little change in the rumen.

LEUKOCYTE MOTILITY: II. EFFECT OF ABSENCE OF GLUCOSE IN MEDIUM; EFFECT OF PRESENCE OF DEOXYGLUCOSE, DINITROPHENOL, PUROMYCIN, ACTINOMYCIN D, AND TRYPSIN ON THE RESPONSE TO CHEMOTACTIC SUBSTANCE; EFFECT OF SEGREGATION OF CELLS FROM CHEMOTACTIC SUBSTANCE

1967 ◽  
Vol 45 (2) ◽  
pp. 269-280 ◽  
Author(s):  
Bruce M. Carruthers
Keyword(s):  
Actinomycin D ◽  
Suppressive Effect ◽  
Inhibitory Effect ◽  
Medium Effect ◽  
Inhibitory Effects ◽  
In Vitro Motility ◽  
Directed Motility ◽  
A Minor ◽  
Chemotactic Effect

The random and directed motility of human leukocytes was studied in vitro. Motility was found not to be dependent upon glucose in the medium. 2-Deoxyglucose was found to inhibit all motility completely. Dinitrophenol had a minor suppressive effect on both random and directed motility. Puromycin at 10−3 M and actinomycin D at 10 μg/ml had a disproportionately great inhibitory effect on directed motility, when compared with minor inhibitory effects on random motility. Actinomycin D at 20 μg/ml and trypsin at 0.1 mg/ml were found to inhibit both types of motility almost completely. Segregation of starch from the field of leukocyte motility was found to abolish its chemotactic effect. Restoration of some chemotactic influence was seen if both starch and leukocytes were present in the segregated area.

Effects of heavy metals and other trace elements on the fermentative activity of the rumen microflora and growth of functionally important rumen bacteria

1978 ◽  
Vol 24 (3) ◽  
pp. 298-306 ◽  
Author(s):  
C. W. Forsberg
Keyword(s):  
Trace Elements ◽  
Rumen Fluid ◽  
Inhibitory Effect ◽  
Rumen Bacteria ◽  
Inhibitory Effects ◽  
Butyrivibrio Fibrisolvens ◽  
Fermentative Activity ◽  
Rumen Microflora ◽  
High Concentrations

The inhibitory effects of high concentrations of essential and non-essential trace elements were tested on the rumen microflora using the rate of fermentation in vitro as the assay. The elements (and the concentration causing 50% inhibition) in decreasing order of toxicity were Hg2+ (20 μg/ml), Cu2+ (21 μg/ml), Cr6+ (70 μg/ml), Se4+ (73 μg/ml), Ni2+ (160 μg/ml), Cd2+ (175 μg/ml), As3+ (304 μg/ml), and As5+ (1610 μg/ml). The elements tested that were either weak or non-inhibitory at concentrations greater than 400 μg/ml included Zn2+, Cr2+, Fe2+, Mn2+, Pb2+, and Co2+. Methylmercury was as inhibitory as mercuric chloride to the fermentation. When the inhibitory effect of Cd2+ was tested on separated bacterial and protozoal fractions, it was more inhibitory to the bacteria. The inhibitory effects of trace elements were also determined for a number of axenic cultures of rumen bacteria. The bacteria which most frequently exhibited the greatest sensitivity were Bacteroides succinogenes, Ruminococcus albus, Bacteroides amytophilus, and Eubacterium ruminantium. Those often exhibiting intermediate sensitivities included Butyrivibrio fibrisolvens, Selenomonas niminantium, and Megasphera elsdenii, while Streptococcus bovis was very refractory to all elements tested. Rumen fluid provided a modest protective effect for the bacteria.

scholarly journals Effect of glucose on fermentation heat in sheep rumen fluid in vitro

1986 ◽  
Vol 56 (1) ◽  
pp. 305-311 ◽  
Author(s):  
A. Arieli
Keyword(s):  
Heat Production ◽  
High Glucose ◽  
Infinite Dilution ◽  
Rumen Fluid ◽  
Heat Production Rate ◽  
Sheep Rumen ◽  
Effect Of Glucose ◽  
Dose Dependent Increase ◽  
Dose Dependent

1. Heat production rate (H) of rumen fluid was measured in a direct calorimeter, Basal H of samples of 15 ml rumen fluid mixed with 45 ml buffer was 0.4 mW/ml rumen fluid.2. Addition of glucose (0.4–6.4 mg/sample) was followed by a dose-dependent increase in H. Maximal H was 1.1 rnW/ml and lasted up to 5 min, returning thereafter to the basal level.3. Expression of fermentation heat (Hf; kJ/mol substrate added) against glucose dose indicated an asymptotic dose response.4. Maximal Hf(at infinite dilution) agreed with stoichiometric calculations whereas minimal Hfsuggested a partial fermentation of the substrate at a high-glucose dose in the rumen environment.

scholarly journals Alpha Interferon and Not Gamma Interferon Inhibits Salmonid Alphavirus Subtype 3 Replication In Vitro

2010 ◽  
Vol 84 (17) ◽  
pp. 8903-8912 ◽  
Author(s):  
Cheng Xu ◽  
Tz-Chun Guo ◽  
Stephen Mutoloki ◽  
Øyvind Haugland ◽  
Inderjit S. Marjara ◽  
...  
Keyword(s):  
Inhibitory Effect ◽  
Cellular Protein ◽  
Alpha Interferon ◽  
Initiation Factor ◽  
Antiviral State ◽  
Antiviral Responses ◽  
Initiation Factor 2 ◽  
A Minor

ABSTRACT Salmonid alphavirus (SAV) is an emerging virus in salmonid aquaculture, with SAV-3 being the only subtype found in Norway. Until now, there has been little focus on the alpha interferon (IFN-α)-induced antiviral responses during virus infection in vivo or in vitro in fish. The possible involvement of IFN-γ in the response to SAV-3 is also not known. In this study, the two IFNs were cloned and expressed as recombinant proteins (recombinant IFN-α [rIFN-α] and rIFN-γ) and used for in vitro studies. SAV-3 infection in a permissive salmon cell line (TO cells) results in IFN-α and IFN-stimulated gene (ISG) mRNA upregulation. Preinfection treatment (4 to 24 h prior to infection) with salmon rIFN-α induces an antiviral state that inhibits the replication of SAV-3 and protects the cells against virus-induced cytopathic effects (CPE). The antiviral state coincides with a strong expression of Mx and ISG15 mRNA and Mx protein expression. When rIFN-α is administered at the time of infection and up to 24 h postinfection, virus replication is not inhibited, and cells are not protected against virus-induced CPE. By 40 h postinfection, the alpha subunit of eukaryotic initiation factor 2 (eIF2α) is phosphorylated concomitant with the expression of the E2 protein as assessed by Western blotting. Postinfection treatment with rIFN-α results in a moderate reduction in E2 expression levels in accordance with a moderate downregulation of cellular protein synthesis, an approximately 65% reduction by 60 h postinfection. rIFN-γ has only a minor inhibitory effect on SAV-3 replication in vitro. SAV-3 is sensitive to the preinfection antiviral state induced by rIFN-α, while postinfection antiviral responses or postinfection treatment with rIFN-α is not able to limit viral replication.

scholarly journals Excretion of purine derivatives by ruminants: recycling of allantoin into the rumen via saliva and its fate in the gut

1990 ◽  
Vol 63 (2) ◽  
pp. 197-205 ◽  
Author(s):  
X. B. Chen ◽  
F. D. DeB. Hovell ◽  
E. R. ØRskov
Keyword(s):  
Fatty Acids ◽  
Uric Acid ◽  
Urinary Excretion ◽  
Volatile Fatty Acids ◽  
Rumen Fluid ◽  
Purine Derivatives ◽  
Complete Destruction ◽  
Series Of Experiments ◽  
Micro Organisms

The saliva of sheep was shown to contain significant concentrations of uric acid (16 (sd) 4.5) μmol/l) and allantoin (120 (sd 16.4) μmol/l), sufficient to recycle purine derivatives equivalent to about 0.10 of the normal urinary excretion. When allantoin was incubated in vitro in rumen fluid, it was degraded at a rate sufficient to ensure complete destruction of recycled allantoin. In a series of experiments in which allantoin was infused into the rumen of sheep fed normally, or into the rumen or abomasum of sheep and the rumen of cattle completely nourished by intragastric infusion of volatile fatty acids and casein, no additional allantoin was recovered in the urine. These losses were probably due to the degradation of allantoin by micro-organisms associated with the digestive tract. It is concluded that all allantoin and uric acid recycled to the rumen via saliva will be similarly degraded. Therefore, the use of urinary excretion of purine derivatives as an estimator of the rumen microbial biomass available to ruminants will need to be corrected for such losses.

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