Suicide phenomenon in mesophilic aeromonads as a basis for species identification.

The acetic acid-mediated suicide phenomenon in mesophilic aeromonads in conjunction with tests for aerogenicity and esculin hydrolysis served as the basis for species identification. Of 210 Aeromonas isolates tested at 30 degrees C, 88 were identified as Aeromonas hydrophila (nonsuicidal, aerogenic, esculin positive), 52 were identified as A. sobria (suicide variable, aerogenic, esculin negative), and 70 were identified as A. caviae (suicidal, anaerogenic, esculin positive). These identifications paralleled those achieved by biochemical criteria.

Anaerobic digestion of organic fraction of municipal solid wastes--digester performance.

The anaerobic digestion of source separated organic fraction of municipal solid wastes was studied by using a stirred 3 cubic meter working volume reactor fed on a semicontinuous basis. The behaviour and performance of the digester at various organic loading rates was illustrated with particular regard to turnover of the gas production rate during a cycle in the digester feed.

Energy balances of eight volunteers fed on diets supplemented with either lactitol or saccharose.

1. Complete 24 h energy and nitrogen balances were measured for eight subjects both while consuming a basal diet supplemented with 49 g saccharose/d (diet S) and while consuming the same basal diet but supplemented with 50 g lactitol monohydrate/d (diet L). 2. The subjects ate the two diets for 8 d. Faeces and urine were collected for the final 4 d. Exchange of respiratory gases (oxygen, carbon dioxide, hydrogen and methane) was measured during the final 72 h while the subjects stayed in an open-circuit respiration chamber, 11 m3, and simulated office work. Before eating diet L, subjects ate 50 g lactitol daily for 10 d. 3. On diets L and S, faecal moisture content averaged 0.787 and 0.753 g/g respectively, the difference being significant (P less than 0.05). On diet L, energy and nitrogen digestibilities and energy metabolizability averaged 0.922, 0.836 and 0.881 respectively, and on diet S 0.935, 0.869 and 0.896 respectively; the differences were also significant (P less than 0.05). Urinary energy losses and N balances were not significantly different for the two diets. 4. In all subjects only traces of methane were produced but hydrogen production differed significantly (P less than 0.05) for diets L and S, being 2.3 and 0.4 litres (normal temperature and pressure)/d respectively. 5. Intakes of metabolizable energy (ME) were corrected, within subjects, to energy equilibrium and equal metabolic body-weight. The corrected ME intakes did not show differences between diets. However, when on diet L the subjects were probably less active than when on diet S because differences within subjects of ankle actometer counts between diets showed a high correlation with the corresponding differences in corrected ME intakes (r 0.92). Further correction of ME intake toward equal actometer activity showed a significant (P less than 0.05) difference between diets: for maintaining energy equilibrium 5.6 (SE 0.8; P less than 0.05)% more ME from diet L was needed than from diet S. The reliability of this 5.6% difference depends on whether or not one ankle actometer gives an accurate picture of the subject's physical activity. 6. The energy contribution to the body is clearly smaller from lactitol than from saccharose, certainly due to the effect of lactitol on digestion, and probably also due to the effect on the utilization of ME.

Hematologic effects of the high-energy endocardial ablation technique.

Ablation of atrioventricular conduction is now widely accepted in the management of supraventricular arrhythmias. Reports of high temperatures, high pressures, and gas production suggest that there may be adverse effects on the blood, the electrode, and the cardiovascular system. In this investigation, using samples of fresh, heparinized pig blood, we measured hemolytic damage, the liberated gas volume and composition, and electrode erosion associated with high-energy electrical ablation. The blood was tested in a 10 liter tank at room temperature. Impulses of 10 to 400 J were applied to new USCI No. 6F bipolar pacing electrodes using both positive and negative polarities. Voltage and current waveforms were recorded. The volume of gas liberated with cathodal electrodes was 0.50 microliter/J up to 50 J and 0.29 microliter/J above 100 J. It was composed predominantly of hydrogen and nitrogen, with carbon dioxide and oxygen. With positive electrodes, the gas volume was linearly related to energy at 4.34 microliter/J up to 200 J and also contained carbon monoxide. The hemolysis was directly proportional to impulse energy for both cathodal and anodal electrodes, being 1.37 microliter/J and 4.48 microliters/J, respectively. Electrode erosion was substantial but clinically acceptable. We conclude that there are marked differences in the energy conversion processes and, where the same energy can achieve a comparable clinical effectiveness, there are advantages in using a cathodal electrode polarity. It is also advisable to use lower energies.

[Gas chromatographic-mass spectrometric analysis of gases produced by Trichomonas vaginalis in vitro].

Five strains of Trichomonas vaginalis were independently inoculated into Cysteine-Peptone-Liver infusion-Maltose medium (CPLM medium), and gases in the culture bottle were qualitatively analysed at five days after the inoculation by gas chromatography mass spectrometry (GC-MS). Methane, ethane and carbon dioxide were commonly found in the gases produced during the culture of Trichomonas vaginalis in vitro. Carbon monoxide was also found in the gases from 4 of 5 strains. Small amount of both ethylene and propane was also noted in 3 of 5 strains. These gaseous molecules were supposed to be produced by Trichomonas vaginalis in vitro, presumably by the catabolism of amino acids. It was also suggested that these gases, including methane, ethane, carbon dioxide, carbon monoxide, ethylene and propane, were responsible for the foamy discharge found in the vagina of patients with Trichomonas vaginalis.

Rapid single-tube confirmatory test for Escherichia coli.

A single-tube confirmatory test that allows a result to be obtained in 4 h has been developed from the single-tube confirmatory test recomended by the Joint Committee of the Public Health Laboratory Service and the Standing Committee of Analysts (PHLS/SCA, 1980). A variety of river, lake and reservoir samples were examined for the presence of E. coli using either most probable number (MPN) or membrane filtration (MF) technique, and the PHLS/SCA recommended confirmatory medium (LTMB) was evaluated against traditional methods. To improve the performance of LTMB, the medium was modified and this modified medium when used in 0.1 ml volumes and incubated for 4 h at 44 degrees C provided 99% agreement with traditional methods.

In vitro digestion of bloat-safe and bloat-causing legumes by rumen microorganisms: gas and foam production.

Leaves of three bloat-safe legumes -- birdsfoot trefoil (Lotus corniculatus L.), sainfoin (Onobrychis viciaefolia Scop.), and cicer milkvetch (Astralagus cicer L.) -- and of three bloat-causing legumes -- alfalfa (Medicago sativa L.), red clover (Trifolium pratense L.), and white clover (Trifolium repens L.) -- were incubated with strained rumen fluid or with mixed rumen fluid and solids. Gas released was measured during the early period (0 to 22 h) of this in vitro digestion. Gas volume was greater with a 1:1 (wt/vol) mixture of solid and fluid rumen contents than with rumen fluid alone. It was greater with whole and chewed leaves from the bloat-causing legumes than with whole leaves from the bloat-safe legumes. However, when leaves were homogenized, volumes of gas from bloat-causing and bloat-safe legumes were similar. More gas was released from homogenized leaves than from the same weight of whole leaves. The amount of foam produced on chewed herbage and homogenized leaves of bloat-causing legumes was greater than on those of bloat-safe legumes. These results are consistent with the rate of disintegration and digestion of legumes by rumen bacteria being an important determinant in pasture bloat. Measurement of gas produced early in in vitro digestion may provide a useful bioassay for evaluating the bloat-causing potential of legumes in breeding selections if variability of the method can be reduced.

[System for cultivation of bacteria to follow up gas production (author's transl)]. / System einer Bakterienkultivierung zur Verfolgung der Gasproduktion.

The construction, workwise and handling of a system for cultivation of bacteria to follow up gas production is described.

[Microflora and the potential capacity for gas formation of the bottom deposits of the Ivan and Arakhlei lakes (the Baikal region)]. / Mikroflora i potentsial'naia sposobnost' k gazoobrazovaniiu donnykh otlozhenii Ivano-Arakhleiskikh ozer (Zabaikal'e).

The number of microorganisms and bacterial biomass in ooze deposits of the Ivano-Arakhleyskiye Lakes (Zabaikalye) decrease unevenly downward the ground column. This decrease is more sharp near the shores. The total number and bacterial biomass of the ground microflora directly depend on the extent of trophicity of the lakes. Gas production in the lakes Irgen, Ivan and Arakhley is accomplished by bacteria and involves exocellular enzymes. The rate of gas production differs among the lakes, along their horizontal layers, and in the vertical cross-section of sediments. The technique for determining the rate of gas production proposed by M. A. Messineva has been successive when applied to the ground of the Ivano-Arakhleyskiye Lakes.

Inhibition of gas vesicle production in Microcyclus aquaticus by L-lysine.

The timing and degree of gas vesicle production in Microcyclus aquaticus was affected by nutritional conditions. If 50 microng L-lysine/ml was added to a glucose-mineral salts medium (DM), the organism did not form gas vesicles. This effect was specific for L-lysine, as neither D-lysine nor meso-diaminopimelic acid prevented gas vesicle production. Cells grown in the presence of L-lysine did not contain any immunologically detectable gas vesicle protein, which indicates that L-lysine affects expression of the structural gene for the gas vesicle protein rather than assembly of the protein into gas vesicles. The addition of L-lysine to cultures in DM did not immediately decrease the rate of gas vesicle assembly, nor did the removal of cells from DM plus L-lysine to DM result in immediate gas vesicle production. Gas vesicle production was also affected by the addition of L-threonine or L-cysteine to culture media or by an increase in the medium's ionic strength. These results are discussed in relation to the aspartic acid pathway of amino acid biosynthesis and effects upon the intracellular L-lysine concentration.

Factors affecting the uptake and metabolism of soluble carbohydrates by the rumen ciliate Dasytricha ruminantium isolated from ovine rumen contents by filtration.

A filtration technique is described whereby metabolically-active suspensions of Dasytricha ruminantium can be isolated from rumen contents with negligible contamination by bacteria or other protozoa. The effects of environmental factors and of the diurnal cycle of the rumen on the uptake and metabolism of soluble carbohydrates by these isolated cells were examined. The principal contribution of the protozoan metabolic end-products to the host ruminant is the supply of lactic, acetic and butyric acids during periods when soluble sugars are in excess.

Clinical aspects of anaerobic infections in the surgical patient.

Oxygen-sensitive anaerobic bacteria comprise the largest group of organisms among the human endogenous microflora. The oral cavity, vagina and colon are the areas where obligate anaerobes are predominant and can be isolated in very high numbers. Sepsis following surgery of any of these organs is frequently due to the escape of endogenous bacteria during the course of the operative procedure. To isolate and successfully identify most of these anaerobic microorganisms from clinical exudate, special collection and bacteriologic techniques are necessary. The acceptable anaerobic collection techniques mentioned above minimize exposure of the clinical specimen to atmospheric oxygen during collection and transfer. Clinical clues indicating anaerobic sepsis include a putrid odor of the exudate and evidence of abscess, necrosis or associated gas formation. The importance and value of the Gram stain in early identification of surgical sepsis is stressed. Treatment of infectious complications includes surgical drainage and specific antibiotics.