Biomedical subjects

M J McInerney

Publications and source records attributed to M J McInerney.

At least 37 records · Page 2Linked to original sources

PubMed1990

Substitution of DL-methionine for soybean meal as a winter supplement for gestating cows grazing native range.

A winter grazing study was conducted to determine whether DL-methionine could replace soybean meal as a N supplement for gestating beef cows. During two winters (Trial 1, n = 51; Trial 2, n = 60), crossbred beef cows grazed native foothill range. Three treatment groups were supplemented with either none (CON), DL-methionine (7.5 g Trial 1 and 9 g Trial 2) in .5 kg beet pulp carrier (BPM) or .4 kg soybean meal (SBM). Cows were supplemented individually every other day. Small differences were noted in cow BW, condition score and blood metabolites. Unsupplemented cows lost the greatest amount of BW (P less than .01) in both trials and lost more (P less than .05) condition during Trial 1 than cows fed BPM or SBM supplements. Blood samples were obtained on two consecutive days during each trial (45 d and 25 d prepartum) and analyzed for blood urea N, total bilirubin, creatinine, albumin, total protein and cholesterol. A treatment x day preparatum interaction (P less than .05) was noted for blood urea. Blood urea nitrogen declined as gestation length increased for CON and SBM cows, but blood urea of BPM-supplemented cows remained low and unchanged. In situ forage digestion was measured in 12 ruminally cannulated cows (four/treatment). In both trials, in situ rate of NDF disappearance was greater (P less than .05) for SBM than for BPM. In Trial 2, a treatment x sampling hour interaction was detected for purine concentration of whole ruminal contents; SBM maintained greater purine concentrations throughout the 48-h supplementation cycle than BPM did. Principal component analysis suggested that ruminal ammonia limited the microbial growth response to DL-methionine. Therefore, alternate-day supplementation of DL-methionine plus beet pulp did not effectively substitute for soybean meal in these trials.

Animal Feed↗

PubMed1990

Influence of lasalocid and supplement level on productivity of gestating ewes grazing winter range.

Two winter feeding trials (1985-86; 1986-87) were conducted to evaluate the productivity of gestating ewes fed lasalocid (L) and two supplement levels while grazing Montana winter range. Five hundred range ewes were randomized within age and breed each year and allotted to .15 or .23 kg hd-1.d-1 of a 20% CP supplement and either no L or L at 70 mg hd-1.d-1. Feed treatments began on 18 Dec. approximately 100 d before the first expected lambing date and continued for 84 d. Ewes fed .23 kg of supplement per day gained more (P less than .01) total weight (4.9 vs 4.0 kg) during the 84-d experiment and had higher (P less than .05) grease fleece weights (4.2 vs 4.0 kg) than those fed .15 kg of supplement. Lasalocid had no effect (P greater than .05) on ewe weight change or grease fleece weights. Supplement level had no effect (P greater than .05) on reproduction, lamb mortality and lamb performance. Ewes fed L had a greater (P less than .05) percentage of lambs born per ewe than those not fed L (120.7 vs 112.1%); lamb performance was similar (P greater than .05) between treatments. However, because a greater percentage of lambs were born per ewe starting the experiment, ewes fed L produced more (P less than .05) kilograms of weaned lamb than those not fed L (25.9 vs 23.4 kg). In conclusion, ewes fed L and grazing winter range weaned more kg of lamb than did controls because of an improved lambing percentage.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗

PubMed1990

The effects of ruminal escape protein or fat on nutritional status of pregnant winter-grazing beef cows.

This study was designed to determine the influence of soybean meal supplementation, with or without additional ruminal escape protein or fat, on the nutritional status of pregnant winter-grazing beef cows. During two winters (Trials 1 and 2), approximately 60 prepartum beef cows grazed native foothills range each year. Cows were allotted randomly to five groups and supplemented (g/d) with either none (control); 570 soybean meal (SOY); 450 soybean meal plus 230 blood meal (SOY + BM); 140 soybean meal, 16 urea plus 450 corn gluten meal (SOY + CGM); or 570 soybean meal plus 210 animal fat (SOY + FAT). These supplements were designed to supply similar quantities of ruminal degraded protein while varying in escape protein quantity and source (SOY + BM and SOY + CGM). Condition scores and body weights were determined at trial initiation (mid-December) and conclusion (early March). Eight blood samples obtained over 4 d during three periods (9, 4 and 1 wk prior to parturition) were analyzed for concentrations of glucose, urea nitrogen (N), total bilirubin, creatinine, albumin, total protein and cholesterol. Cows in the control treatment experienced the greatest BW loss in both trials. In Trial 2, escape protein tended to decrease (P less than .06) BW loss compared to SOY, though loss tended to be greater (P less than .08) with SOY + CGM than with SOY + BM. Escape protein can enhance nutritional status when supplemented with .6 kg/d of soybean meal.

Animal Feed↗

PubMed1989

Effects of Organic Acid Anions on the Growth and Metabolism of Syntrophomonas wolfei in Pure Culture and in Defined Consortia.

The effects of organic acid anions on the growth of Syntrophomonas wolfei was determined by varying the initial concentration of the acid anion in the medium. The addition of 15 mM acetate decreased the growth rate of a butyrate-catabolizing coculture containing Methanospirillum hungatei from 0.0085 to 0.0029 per hour. Higher initial acetate concentrations decreased the butyrate degradation rate and the yield of cells of S. wolfei per butyrate degraded. Inhibition was not due to the counter ion or the effect of acetate on the methanogen. Initial acetate concentrations above 25 mM inhibited crotonate-using pure cultures and cocultures of S. wolfei. Benzoate and lactate inhibited the growth of S. wolfei on crotonate in pure culture and coculture. Lactate was an effective inhibitor of S. wolfei cultures at concentrations greater than 10 mM. High concentrations of acetate and lactate altered the electron flow in crotonate-catabolizing cocultures, resulting in the formation of less methane and more butyrate and caproate. The inclusion of the acetate-using methanogen, Methanosarcina barkeri, in a methanogenic butyrate-catabolizing coculture increased both the yield of S. wolfei cells per butyrate degraded and the efficacy of butyrate degradation. Butyrate degradation by acetate-inhibited cocultures occurred only after the addition of Methanosarcina barkeri. These results showed that the metabolism of S. wolfei was inhibited by high levels of organic acid anions. The activity of acetate-using methanogens is important for the syntrophic degradation of fatty acids when high levels of acetate are present.

Journal Article↗

PubMed1989

Mechanisms of microbial movement in subsurface materials.

The biological factors important in the penetration of Escherichia coli through anaerobic, nutrient-saturated, Ottawa sand-packed cores were studied under static conditions. In cores saturated with galactose-peptone medium, motile strains of E. coli penetrated four times faster than mutants defective only in flagellar synthesis. Motile, nonchemotactic mutants penetrated the cores faster than did the chemotactic parental strain. This, plus the fact that a chemotactic galactose mutant penetrated cores saturated with peptone medium at the same rate with or without a galactose gradient, indicates that chemotaxis may not be required for bacterial penetration through unconsolidated porous media. The effect of gas production on bacterial penetration was studied by using motile and nonmotile E. coli strains together with their respective isogenic non-gas-producing mutants. No differences were observed between the penetration rates of the two motile strains through cores saturated with peptone medium with or without galactose. However, penetration of both nonmotile strains was detected only with galactose. The nonmotile, gas-producing strain penetrated cores saturated with galactose-peptone medium five to six times faster than did the nonmotile, non-gas-producing mutant, which indicates that gas production is an important mechanism for the movement of nonmotile bacteria through unconsolidated porous media. For motile strains, the penetration rate decreased with increasing galactose concentrations in the core and with decreasing inoculum sizes. Also, motile strains with the faster growth rates had faster penetration rates. These results imply that, for motile bacteria, the penetration rate is regulated by the in situ bacterial growth rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Anaerobiosis↗

PubMed1989

Formate auxotroph of Methanobacterium thermoautotrophicum Marburg.

A formate-requiring auxotroph of Methanobacterium thermoautotrophicum Marburg was isolated after hydroxylamine mutagenesis and bacitracin selection. The requirement for formate is unique and specific; combined pools of other volatile fatty acids, amino acids, vitamins, and nitrogen bases did not substitute for formate. Compared with those of the wild type, cell extracts of the formate auxotroph were deficient in formate dehydrogenase activity, but cells of all of the strains examined catalyzed a formate-carbon dioxide exchange activity. All of the strains examined took up a small amount (200 to 260 mumol/liter) of formate (3 mM) added to medium. The results of the study of this novel auxotroph indicate a role for formate in biosynthetic reactions in this methanogen. Moreover, because methanogenesis from H2-CO2 is not impaired in the mutant, free formate is not an intermediate in the reduction of CO2 to CH4.

Carbon Radioisotopes↗

PubMed1988

Phospholipid Fatty Acid Composition of the Syntrophic Anaerobic Bacterium Syntrophomonas wolfei.

The membrane phospholipid fatty acids (PLFAs) from several cocultures and a pure culture of Syntrophomonas wolfei were determined by capillary column gas chromatography. Cocultures of S. wolfei with a Desulfovibrio sp. contained PLFAs from both organisms, whereas PLFAs from a coculture with Methanospirillum hungatei contained very little biomass to analyze. The pure culture of S. wolfei grown on crotonate provided the best material for analysis of the PLFAs. The predominant PLFAs of S. wolfei were the monounsaturated 16:1omega7c and 16:1omega9c and the saturated 16:0 and 14:0. A low concentration of the diunsaturated 18:2omega6 was detected. The PLFA analysis provides additional information for consideration in the determination of the profile of PLFAs obtained from anaerobic environments. In addition, this information may aid in the understanding of the physiology and phylogeny of S. wolfei and other syntrophic bacteria.

Journal Article↗

PubMed1988

Influence of body condition and lasalocid during late gestation on blood metabolites, lamb birth weight and colostrum composition and production in Finn-cross ewes.

The objective of this experiment was to examine the effects of body condition (BC) and of lasalocid (L) the last 4 wk of gestation on blood metabolite profiles, lamb birth weight and colostrum composition and production. Twenty-eight 3-yr-old Finn-Targhee ewes (73 kg) were assigned randomly within BC grouping (2.5 or 3.5) and individually fed a diet of 90% alfalfa pellets and 10% of a supplement containing either no L (C = control) or L. Gestation and 24-h postlambing weights were higher (P less than .05) for 3.5 BC versus 2.5 BC ewes. Lasalocid had no effect (P greater than .05) on ewe weight. Average number of lambs born within treatment groups were similar (P greater than .05). Total kilograms of lamb born were greater (P less than .10) for 3.5 BC ewes. Body condition 3.5 ewes had greater concentrations of total protein (P less than .10) and albumin (P less than .05) the last 4 wk of gestation than those in the 2.5 BC group. Feeding L decreased (P less than .05) blood urea-N in comparison with C ewes. Colostrum composition and production were not influenced (P greater than .05) by BC, L or number of lambs born. Serum 3-hydroxybutyrate seemed to be a good indicator of energy metabolism; albumin and blood urea-N concentrations reflected dietary protein intake. Lasalocid had a minimal effect on nutrient metabolism and productivity of ewes fed in excess of the NRC (1985) protein and energy requirements.

Animals↗

PubMed1987

Separation of Syntrophomonas wolfei from Methanospirillum hungatii in Syntrophic Cocultures by Using Percoll Gradients.

Percoll gradient centrifugation effectively separated Syntrophomonas wolfei cells from Methanospirillum hungatii cells, resulting in a 70- to 80-fold enrichment of S. wolfei cells relative to M. hungatii cells. The separated S. wolfei cells were viable. Gram quantities of cellular protein which was enzymatically active and had low levels of contamination by the methanogenic cofactor, factor(420), were obtained.

Journal Article↗

PubMed1987

Influence of biostimulation by mature bulls on occurrence of puberty in beef heifers.

The objective of this study was to determine if biostimulation of prepuberal beef heifers by mature bulls would alter proportions of heifers exhibiting puberty, or age or weight at puberty. Angus (A), A X Hereford (H) and Tarentaise X HA heifers (n = 103) were stratified by age and weight within breed-type and location of birth and allotted randomly to the following treatments: 1) heifers exposed to mature bulls (T1; n = 52) or 2) heifers isolated from bulls (T2; n = 51). At the start of the experiment, heifers in T1 and T2 were 287 +/- 2 and 286 +/- 2 d of age, respectively. Male-to-female ratio for T1 was 1:26. Heifers in T1 and T2 were maintained in drylots separated by .5 km. Heifers were observed for estrus twice daily for 152 d. Puberty was characterized by the following criteria: 1) behavioral estrus, 2) presence of a palpable corpus luteum (d 9; estrus = d 0) and 3) a rise in serum progesterone above 1 ng/ml (d 9). Proportions of heifers reaching puberty by 11, 12, 13, 14 and 15 mo of age did not differ (P greater than .10) between treatments. Percentages of heifers reaching puberty by the end of the experiment were 84 and 89% for T1 and T2, respectively. Age and weight at puberty did not differ (P greater than .10) between treatments and averaged 370 +/- 7 d and 293 +/- 4 kg, respectively. Results from this experiment indicated that presence of mature bulls did not alter proportions of beef heifers reaching puberty, or age and weight at puberty.

Animals↗

PubMed1986

Effect of Sterilization by Dry Heat or Autoclaving on Bacterial Penetration through Berea Sandstone.

A study was undertaken to determine why bacteria could penetrate lengths of consolidated sandstone (Berea) faster when the sandstone was sterilized by autoclaving than when dry heat (150 degrees C, 3 h) was used. Changes in permeability, porosity, and pore entrance size of the rock as a result of autoclaving were not sufficient to explain the differences in penetration times observed, but electron dispersion spectroscopy and electron microscopy of the rock revealed changes in mineral composition and clay morphology. Autoclaved cores contained more chloride than dry-heated cores, and the clays of autoclaved cores were aggregated and irregularly shaped. Therefore, the decreases in bacterial penetration rates caused by autoclave sterilization were probably the result of a change in surface charge of the pores of the rock and of a reduction in surface area of clays available for adhesion. The results implied that dry-heat sterilization was preferable to autoclaving when examining biotic and abiotic interactions in a native-state rock model.

Journal Article↗

PubMed1986

Method for detection of microorganisms that produce gaseous nitrogen oxides.

A method was developed to detect NO- or N(2)O-producing bacteria in solid or liquid medium by their ability to oxidize the redox indicator resazurin from its reduced colorless form to its oxidized pink form. The method was sensitive to as little as 35 nM N(2)O or 0.5 nM NO. Ninety-one percent of the colonies that oxidized resazurin on plates also produced N(2)O in slant cultures. Forty-four percent of the colonies that did not oxidize resazurin did produce N(2)O. This percentage was reduced to 15% when colonies in which the coloration was difficult to discern were picked to slants to determine whether they oxidized the slant. The production of N(2)O preceded the oxidation of resazurin by liquid cultures of Escherichia coli and a sludge isolate. With the denitrifying sewage isolate, the disappearance of N(2)O was followed by the return of resazurin to its reduced state. Wolinella succinogenes was found to produce small amounts of N(2)O from NO(3), which resulted in a transient oxidation of resazurin.

Journal Article↗

PubMed1986

Effect of nitrate on biogenic sulfide production.

The addition of 59 mM nitrate inhibited biogenic sulfide production in dilute sewage sludge (10% [vol/vol]) amended with 20 mM sulfate and either acetate, glucose, or hydrogen as electron donors. Similar results were found when pond sediment or oil field brines served as the inoculum. Sulfide production was inhibited for periods of at least 6 months and was accompanied by the oxidation of resazurin from its colorless reduced state to its pink oxidized state. Lower amounts of nitrate (6 or 20 mM) and increased amounts of sewage sludge resulted in only transient inhibition of sulfide production. The addition of 156 mM sulfate to bottles with 59 mM nitrate and 10% (vol/vol) sewage sludge or pond sediment resulted in sulfide production. Nitrate, nitrite, and nitrous oxide were detected during periods where sulfide production was inhibited, whereas nitrate, nitrite, and nitrous oxide were below detectable levels at the time sulfide production began. The oxidation of resazurin was attributed to an increase in nitrous oxide which persisted in concentration of about 1.0 mM for up to 5 months. The numbers of sulfate-reducing organisms decreased from 10 CFU ml sludge to less than detectable levels after prolonged incubation of oxidized bottles. The addition of 10 mM glucose to oxidized bottles after 14.5 weeks of incubation resulted in rereduction of the resazurin and subsequent sulfide production. The prolonged inhibition of sulfide production was attributed to an increase in oxidation-reduction potential due to biogenic production of nitrous oxide, which appeared to have a cytotoxic effect on sulfate-reducing populations.

Journal Article↗

PubMed1986

Isolation of halotolerant, thermotolerant, facultative polymer-producing bacteria and characterization of the exopolymer.

Over 200 bacterial strains were selected for anaerobic growth at 50 degrees C and extracellular polysaccharide production in a sucrose-mineral salts medium with NaNO(3) and up to 10% NaCl. The predominant cell type was an encapsulated gram-positive, motile, facultative sporeforming rod similar to Bacillus species. Strain SP018 grew and produced the polysaccharide on a variety of substrates at salinities up to 12% NaCl. Good polymer production only occurred anaerobically and was optimal between 4 and 10% NaCl. The ethanol-precipitated SP018 polymer was a charged heteropolysaccharide that contained glucose, mannose, arabinose, ribose, and low levels of allose and glucosamine. The SP018 polymer showed pseudoplastic behavior, was resistant to shearing, and had a higher viscosity at dilute concentrations and at elevated temperatures than xanthan gum. High-ionic-strength solutions reversibly decreased the viscosity of SP018 polymer solutions. The bacterium and the associated polymer have many properties that make them potentially useful for in situ microbially enhanced oil recovery processes.

Journal Article↗

PubMed1986

Preparation of cell-free extracts and the enzymes involved in fatty acid metabolism in Syntrophomonas wolfei.

Syntrophomonas wolfei is an anaerobic fatty acid degrader that can only be grown in coculture with H2-using bacteria such as Methanospirillum hungatei. Cells of S. wolfei were selectively lysed by lysozyme treatment, and unlysed cells of M. hungatei were removed by centrifugation. The cell extract of S. wolfei obtained with this method had low levels of contamination by methanogenic cofactors. However, lysozyme treatment was not efficient in releasing S. wolfei protein; only about 15% of the L-3-hydroxyacyl-coenzyme A (CoA) dehydrogenase activity was found in the lysozyme supernatant. Cell extracts of S. wolfei obtained with this method had high specific activities of acyl-CoA dehydrogenase, enoyl-CoA hydratase, L-3-hydroxyacyl-CoA dehydrogenase, and 3-ketoacyl-CoA thiolase. These activities were not detected in cell extracts of M. hungatei grown alone, confirming that these activities were present in S. wolfei. The acyl-CoA dehydrogenase activity was high when a C4 but not a C8 or C16 acyl-CoA derivative served as the substrate. S. Wolfei cell extracts had high CoA transferase specific activities and no detectable acyl-CoA synthetase activity, indicating that fatty acid activation occurred by transfer of CoA from acetyl-CoA. Phosphotransacetylase and acetate kinase activities were detected in cell extracts of S. wolfei, indicating that S. wolfei is able to perform substrate-level phosphorylation.

3-Hydroxyacyl CoA Dehydrogenases↗

PubMed1985

Microbial Penetration through Nutrient-Saturated Berea Sandstone.

Penetration times and penetration rates for a motile Bacillus strain growing in nutrient-saturated Berea sandstone cores were determined. The rate of penetration was essentially independent of permeabilities above 100 mdarcys and rapidly declined for permeabilities below 100 mdarcys. It was found that these penetration rates could be grouped into two statistically distinct classes consisting of rates for permeabilities above 100 mdarcys and rates for those below 100 mdarcys. Instantaneous penetration rates were found to be zero order with respect to core length for cores with permeabilities above 100 mdarcys and first order with respect to core length for cores with permeabilities below 100 mdarcys. The maximum observed penetration rate was 0.47 cm . h, and the slowest was 0.06 cm . h; however, these rates may be underestimates of the true penetration rate, since the observed rates included the time required for growth in the flask as well as the core. The relationship of penetration time to the square of the length of the core suggested that cells penetrated high-permeability cores as a band and low-permeability cores in a diffuse fashion. The motile Enterobacter aerogenes strain penetrated Berea sandstone cores three to eight times faster than did the nonmotile Klebsiella pneumoniae strain when cores of comparable length and permeability were used. A penetration mechanism based entirely on motility predicted penetration times that were in agreement with the observed penetration times for motile strains. The fact that nonmotile strains penetrated the cores suggested that filamentous or unrestricted growth, or both, may also be important.

Journal Article↗

PubMed1985

Anaerobic Production of a Biosurfactant by Bacillus licheniformis JF-2.

Bacillus licheniformis JF-2 anaerobically produced a biosurfactant when grown in a glucose-mineral salts medium containing yeast extract and NaNO(3). Surface tension of the medium was reduced from 70 to 74 mN/m to as low as 28 mN/m due to the production of an anionic biosurfactant.

Journal Article↗

PubMed1984

Respiratory mutants of Azotobacter vinelandii with elevated levels of cytochrome d.

A method is described for the isolation of respiratory mutants of Azotobacter vinelandii with increased amounts of d-type cytochrome by selecting for the inability to reduce tetrazolium red. Five stable mutants were obtained that had six-fold higher levels of cytochrome d, increased amounts of b-type and lower amounts of o-type and c-type cytochromes than the wild-type strain. Spectral alterations in cytochrome alpha 1 were also observed in the mutants. NADH and succinate oxidase activities of membrane particles were about two fold higher in the mutants compared to the wild-type strain. Ascorbate-N,N,N',N'-tetramethyl-p-phenylene diamine oxidase activity was barely detectable in membrane particles of the mutants. These results are consistent with an increase in the amount of the cytochrome d oxidase branch and a decrease in the amount and activity of the cytochrome o, alpha 1 oxidase branch in the mutants. Growth rates under oxygen-excess conditions and respiratory-linked proton translocation ratios of the mutant and wild-type stains were similar as were the photochemical spectral and kinetic properties of cytochrome d.

Azotobacter↗