scholarly journals The metabolism of nitrate and nitrite in the sheep. 2. Hydrogen donators in nitrate reduction by rumen micro-organisms in vitro

1951 ◽  
Vol 49 (2) ◽  
pp. 149-153 ◽  
Author(s):  
D. Lewis
Keyword(s):  
Nitrate Reduction ◽  
Nitrate And Nitrite ◽  
Micro Organisms

scholarly journals Inhibitory effects of sulphur compounds, copper and tungsten on nitrate reduction by mixed rumen micro-organisms

1989 ◽  
Vol 61 (3) ◽  
pp. 741-748 ◽  
Author(s):  
Junichi Takahashi ◽  
Nobuyuki Johchi ◽  
Hiroshi Fujita
Keyword(s):  
Nitrate Reduction ◽  
Rumen Fluid ◽  
Sodium Sulphate ◽  
Microbial Reduction ◽  
Inhibitory Effects ◽  
Sulphur Compounds ◽  
The Media ◽  
Micro Organisms ◽  
And Tungsten

1. The inhibitory effects of inorganic and organic sulphur-containing compounds, copper and tungsten on nitrate reduction by mixed rumen micro-organisms were investigated in two in vitro studies.2. Coarsely strained rumen fluid from nitrate-adapted (Expt 1) or non-adapted (Expt 2) Suffolk Down wethers maintained on lucerne (Medicago sativa) cubes was used as an inoculum. In Expt 1, anaerobic incubation was carried out for 24 h for each medium supplemented with 10 mM-sodium nitrate and the following chemicals: 0, 1, 2, 3, 5, 8 and 10 mM-sodium sulphide, 1 and 10 mM-sodium sulphite, 1 and 10 mM-sodium sulphate, 1 and 10 mM-L-cysteine, 1 and 10 mM-DL-methionine, 1 mM-sodium tungstate and I mM-copper sulphate. In Expt 2, 1 and 10 mM-Na2S, 1 and 10 mM-L-cysteine, 1 mM-Na2WO4, and 1 mM-CuSO4were added to incubation media to test for chemical inhibition of microbial reduction of nitrate.3. In Expt 1, the amount of nitrite formed decreased with increasing concentration of sulphide-S added. The additions of L-cysteine, W and Cu suppressed nitrite formation in media from both nitrate-adapted and non-adapted sheep.4. In contrast to the effects of sulphide, L-cysteine and W counteracted, to some degree, nitrate-induced reduction of volatile fatty acid (VFA) production. Addition of Cu to the media resulted in a further depression of VFA production.

Effect of ionophores on in vitro caecal fermentation in rabbits

1997 ◽  
Vol 128 (4) ◽  
pp. 495-498 ◽  
Author(s):  
M. MAROUNEK ◽  
J. šIMŮNEK ◽  
D. DUšKOVÁ ◽  
V. SKŘIVANOVÁ
Keyword(s):  
Czech Republic ◽  
Hydrogen Atmosphere ◽  
Alternative Method ◽  
Micro Organisms ◽  
Caecal Fermentation ◽  
Stimulation Of

Experiments were carried out at Uhříněves, Czech Republic, in 1995 and 1996 to evaluate the effect of salinomycin, monensin, lasalocid and maduramicin on in vitro rabbit caecal fermentation. In cultures supplied with starch, hemicellulose and pectin, all ionophores in the range of concentrations tested (1–10 μg/ml) stimulated methanogenesis. Ionophores at 5 μg/ml increased the production of methane by 26–35% and decreased the production of acetate (P<0·05). Significantly more acetate was produced in mixotrophic acetogenic cultures of caecal micro-organisms with glucose (2 mg/ml) under hydrogen atmosphere than under nitrogen. The H2-dependent formation of acetate was blocked in cultures with ionophores. The stimulation of methanogenesis by salinomycin, monensin, lasalocid and maduramicin can thus be related to the inhibition of acetogenesis, which is an alternative method of H2 utilization in the rabbit caecum.

Bovine or equine faeces as sources of micro-organisms instead of rumen liquor in the Tilley and Terry in vitro digestibility technique for evaluating forages in Tanzania

1998 ◽  
Vol 1998 ◽  
pp. 172-172
Author(s):  
H. Whittall ◽  
E.J. Mtengeti ◽  
L.A. Mtenga ◽  
D.L. Romney ◽  
E. Owen
Keyword(s):  
Developed Countries ◽  
In Vitro Digestibility ◽  
Less Developed Countries ◽  
Considerable Potential ◽  
Tropical Countries ◽  
Laboratory Conditions ◽  
Hind Gut ◽  
Micro Organisms ◽  
Consequent Improvement

Akhter et al.(1994) demonstrated bovine faeces to have considerable potential as a source of microorganisms to replace rumen liquor in the in vitro digestibility method of Tilley and Terry (1963) for evaluating temperate gramminaceous forages, under UK laboratory conditions. In view of the difficulties and costs of maintaining fistulated animals in tropical, less-developed countries, the present study was undertaken in Tanzania to investigate the potential of bovine faeces as a substitute for rumen liquor in the Tilley and Terry technique for evaluating local, gramminaceous forages. Use of equine faeces was also investigated in view of the prevalence of equines in some tropical countries. It was also hypothesised that equines, being hind-gut fermentors, would yield faeces containing more micro-organisms than faeces from bovines, with a consequent improvement in digestibility.

Survival of cryptosporidium parvum, escherichia coli, faecal enterococci and clostridium perfringens in river water: influence of temperature and autochthonous microorganisms

1997 ◽  
Vol 35 (11-12) ◽  
pp. 249-252 ◽  
Author(s):  
G. J. Medema ◽  
M. Bahar ◽  
F. M. Schets
Keyword(s):  
Surface Water ◽  
River Water ◽  
Cryptosporidium Parvum ◽  
Health Hazard ◽  
Influence Of Temperature ◽  
E Coli ◽  
Untreated Water ◽  
Time Required ◽  
Micro Organisms

Oocysts of Cryptosporidium parvum can survive for several months in surface water, one of the main factors determining their success in environmental transmission and thus their health hazard via water. Several factors in the environment, e.g. temperature, presence of predators and exo-enzymes will probably influence oocyst survival. The high persistence of oocysts may also limit the value of traditional faecal indicator bacteria. The aim of this study was to determine the rate at which C parvum oocysts, E coli, faecal enterococci and C perfringens spores die in surface water and the influence of temperature and the presence of autochthonous (micro)organisms on the die-off rate. Microcosms with autoclaved river water were inoculated with the organisms. Microcosms with untreated river water were inoculated with concentrated primary effluent containing the bacteria and with C parvum oocysts. Microcosms were incubated at 5°C or 15°C at 100rpm. Viability of oocysts was monitored by in vitro excystation and dye-exclusion; viability of the bacteria was determined on appropriate selective media. When pseudo first-order die-off kinetics were assumed, the die-off rate of oocysts at 5°C was 0.010 log10/d and at 15°C, 0.006–0.024 log10/d. These rates underestimate die-off since oocyst disintegration was not accounted for. Incubation in autoclaved or untreated water did influence the die-off rate of oocysts at 15°C but not at 5°C. The die-off rate of E coli and enterococci was faster in the non-sterile river water than in autoclaved water at both temperatures. At 15°C, E coli (and possibly E faecium) even multiplied in autoclaved water. In untreated river water, the die-off of E coli and enterococci was approximately 10x faster than die-off of oocysts but die-off rates of C perfringens were lower than those of oocysts. As for oocysts, die-off of the bacteria and spores was faster at 15°C than at 5°C. Oocysts are very persistent in river water: the time required for a 10x reduction in viability being 40–160d at 15°C and 100d at 5°C. Biological/biochemical activity influenced oocyst survival at 15°C and survival of both vegetative bacteria at 5 and 15°C. The rapid die-off of E coli and enterococci makes them less suitable as indicators of oocyst presence in water. As C perfringens survived longer in untreated river water than oocysts, it may prove useful as an indicator of the presence of C parvum.

The effect of nitrogen source on the in vitro cellulose digestion of chemically treated oat straw and poplar wood

1974 ◽  
Vol 82 (3) ◽  
pp. 571-573 ◽  
Author(s):  
I. O. A. Adeleye ◽  
W. D. Kitts
Keyword(s):  
Ammonium Hydroxide ◽  
Nitrogen Sources ◽  
Energy Fraction ◽  
Digestible Energy ◽  
Dietary Nitrogen ◽  
Microbial Nitrogen ◽  
Appropriate Treatment ◽  
Gross Energy ◽  
Micro Organisms

The gross energy of forages can be classified into three fractions, namely the unavailable fraction, the digestible energy fraction and the potentially digestible energy (PDE) fraction. The PDE fraction can only be made available by appropriate treatment and supplementation (Pigden & Heaney, 1969). In young forages the PDE fraction is relatively insignificant, but as the plant matures, the PDE fraction increases very rapidly. By treating matured forages with delignifying agents, increased nutrient digestibilities have been demonstrated Chandra & Jackson, 1971; Wilson & Pigden, 1964), but no significant improvement on the voluntary intake was achieved unless the treated material was supplemented with a source of nitrogen (Donefer, Adeleye & Jones, 1969). While Zafren (1960) used ammonium hydroxide (NH40H) as the treatment alkali, with the claim that the ammonium acetate resulting from the neutralization of the excess alkali could serve as an extra source of nitrogen in the treated straw, other investigators (Donefer et al. 1969) have adopted the method of supplementing the treated straw with a source of nitrogen. Since the efficiency with which dietary nitrogen is converted to microbial nitrogen in the rumen has a considerable influence on the efficiency the animal as a whole, studies herein reported were carried out to test the effectiveness with which rumen micro-organisms utilize different nitrogen sources in degrading cellulose in vitro.

scholarly journals The Antimicrobial Efficacy of four different Intracanal Medication to Microorganisms existing in the Failure of Endodontic Therapy: An in vitro study

2021 ◽  
Vol 8 (3) ◽  
pp. 01-04
Author(s):  
Jorge Paredes Vieyra ◽  
Fabian Ocampo Acosta ◽  
Francisco Javier Jiménez Enriquez ◽  
Alan Hidalgo Vargas ◽  
Ignacio Manriquez Quintana ◽  
...  
Keyword(s):  
Bacterial Load ◽  
In Vitro Study ◽  
Diffusion Test ◽  
Chemical Combination ◽  
Root Canal System ◽  
Inhibition Zones ◽  
Petri Plate ◽  
Micro Organisms ◽  
And Staphylococcus Aureus

Aim.This study aims to identify the efficacy of different intracanal medication formulations existing in end of endodontic therapy’s failure, and related to strains of Enterococcus faecalis, Pseudomonas aeruginosa, and Staphylococcus aureus in Petri plates. Materials and methods. It was used diffusion test in agar where each Petri plate with the inoculated bacteria. Perforations of approximately 4 mm deep by 5 mm in diameter were made to prepare where the intracanal drug (25 µl) to be tested. The diameters of the bacterial inhibition zones were measured and registered to each tested medication at the period of 24 hours, 48 hours, 7 and 14 days respectively. Results. All the medications promoted inhibition halos. The inhibition halos were represented in mm. A higher elimination of micro-organisms can be significantly achieved through the association of different substances in the formulation of an intra canal medication, with emphasis to Ca (OH)2 combined with nitrofurazone and magnesium oxide respectively. Conclusion. Cleaning and shaping of the root canal system associated with the chemical combination of Ca (OH) 2 with antiseptic pastes or solutions considerably reduce the bacterial load.

scholarly journals Determination of nitrofurantoin and fosfomycin susceptibility among urinary Escherichia coli isolates

2020 ◽  
Vol 8 (9) ◽  
pp. 3274
Author(s):  
Rachana Kanaujia ◽  
Amit Kumar ◽  
Malay Bajpai
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Urine Samples ◽  
E Coli ◽  
Tract Infections ◽  
Therapeutic Alternatives ◽  
Micro Organisms ◽  
Staphylococcus Spp

Background: Urinary tract infections (UTIs) are one of the most common infections. For treatment of UTIs, there are limited antibiotics due to increased resistance among uropathogens. Two older antibiotics; Nitrofurantoin and Fosfomycin have become novel oral therapeutic options against uropathogens. Aim of the study was to identify UTI causing micro-organisms and evaluate in-vitro activity of nitrofurantoin and fosfomycin against most common isolated organism (E. coli).Methods: Results of urine samples culture and susceptibility testing over a period of 1 year were analysed and included in this study.Results: Micro-organisms were isolated from 568 urine samples. Most commonly isolated organism was Escherichia coli (40.50%), followed by Klebsiella spp. (20.07%) and Staphylococcus spp. (17.07%). Susceptibility of E. coli to nitrofurantoin and fosfomycin was 91.74% and 65.65% respectively. Conclusion: Good activity of nitrofurantoin and fosfomycin against E. coli indicates that these two drugs are potential therapeutic alternatives for urinary tract infections.

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.

Anaerobes in ejaculates of subfertile men

1995 ◽  
Vol 1 (5) ◽  
pp. 462-478 ◽  
Author(s):  
Waltraud Eggert-Kruse ◽  
Gerhard Rohr ◽  
Wolfram Ströck ◽  
Susanne Pohl ◽  
Beate Schwalbach ◽  
...  
Keyword(s):  
Tract Infection ◽  
Genital Tract ◽  
Anaerobic Bacteria ◽  
Cervical Mucus ◽  
Anaerobic Growth ◽  
Pathogenic Species ◽  
Genital Tract Infection ◽  
Micro Organisms

Abstract The clinical significance of micro-organisms in semen samples of asymptomatic subfertile patients is a matter of constant debate. Usually little attention is paid to anaerobic bacteria as they are sensitive to transportation and culturing, and differentiation is difficult, costly and time-consuming. In the present study, special screening was carried out for anaerobes in ejaculates in addition to the routine microbial cultures of genital secretions of both partners. In addition to standard semen analysis and evaluation of sperm ability to penetrate cervical mucus (CM) in vivo (postcoital testing) and in vitro using a standardized test system, semen samples from 126 randomly chosen males of couples with a median duration of infertility of 4 years were examined for colonization with anaerobic bacteria. All couples were without clinical signs or symptoms of genital tract infection. The special care taken for anaerobic growth in semen samples gave a high rate of positive cultures and showed that nearly all ejaculates (99%) were colonized with anaerobic micro-organisms, and potentially pathogenic species were found in 71% of men. This rate was more than four times higher than that obtained with routine cultures and standard transportation (16%). Anaerobic bacterial growth of ≥106 colony forming units (CFU)/ml was seen in 42% (total range 103-108 CFU/ml). In addition, aerobic growth was found in 96%(≥106 CFU/ml in 21%), potentially pathogenic species in 61% of semen specimens. There were no marked differences in the prevalence of anaerobic micro-organisms in patients with reduced or normal sperm count, motility or morphology. Nor was there any significant difference in anaerobic colonization between samples with impaired or good ability to penetrate CM of female partners (in vivo or in vitro), or the CM of fertile donors in the in-vitro sperm-cervical mucus penetration test (SCMPT) in this asymptomatic group of patients. There was no clear association between microbial colonization and subsequent fertility in vivo within an observation period of 6 months. The results of this study suggest that anaerobic bacteria are often not detected when routine methods for microbial evaluation are used. This should be considered during assisted reproduction and in patients with symptoms of genital tract infection and should lead to further studies in infertile patients where subclinical infection or inflammation is indicated by specific markers in semen samples.

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