bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of titanium (III) citrate as reducing agent on growth of rumen bacteria
Authors: Jones G A , Pickard M D
Published: January 2020

We compared the growth of 10 strains of rumen bacteria in an anaerobic medium reduced with cysteine hydrochloride, dithiothreitol, or titanium (III) citrate. The redox potential of medium reduced with cysteine hydrochloride was -167.8 mV; with dithiothreitol it was -175.8 mV; and with titanium(III) citrate it was -302.4 mV at a concentration of 5 X 10(-4) M titanium and -403.9 mV at 2 X 10(-3) M titanium. Maximum growth of the strains was generally lower with dithiothreitol or titanium(III) citrate than with cysteine hydrochloride, although growth was greater than in medium lacking an added reducing agent. Strains for which cysteine was required or markedly stimulatory grew only poorly with titanium(III) citrate. No strain grew in medium with sodium citrate as the energy source. Titanium(III) citrate could be used to reduce anaerobic media for some rumen bacteria if the exclusion of a sulfur-containing reducing agent is required.
T-2 metabolites in the excreta of broiler chickens administered 3H-labeled T-2 toxin
Authors: Yoshizawa T , Swanson S P , Mirocha C J
Published: January 2020

A method for the detection of T-2 metabolites was developed and applied to analysis of metabolites in excreta of broiler chickens administered 3H-labeled T-2 toxin. The method used acetonitrile extraction and partitioning with petroleum ether followed by chromatography on Amberlite XAD-2, Florisil, and Sep-Pak C18. The recovery of T-2 toxin added to the chicken excreta was 73% at a concentration of 0.2 microgram/g. About 80% of orally administered 3H-labeled T-2 toxin was rapidly metabolized to more polar derivatives and eliminated in the excreta within 48 h. T-2 toxin, HT-2 toxin, neosolaniol, and T-2 tetraol were detected at 0.06 to 1.13% of the total dose, 48 h after administration. Eight unknown derivatives, named TB-1 to TB-8, were quantitatively more significant than the metabolites above. TB-3 and TB-9 represented about 12 and 25% of the total dose, respectively. One of the metabolites (TB-6), 1.5% of the total dose, was identified as 4-deacetylneosolaniol (15-acetyl-3 alpha, 4 beta, 8 alpha-trihydroxy-12, 13-epoxytrichothec-9-ene).
Anaerobic Transfer of Antibiotic Resistance from
Pseudomonas aeruginosa
Authors: Graves James F. , Riggs Hammond G.
Published: January 2020

Pseudomonas aeruginosa
, an opportunistic pathogen that often initiates infections from a reservoir in the intestinal tract, may donate or acquire antibiotic resistance in an anaerobic environment. Only by including nitrate and nitrite in media could antibiotic-resistant and -sensitive strains of
P. aeruginosa
be cultured in a glove box isolator. These anaerobically grown cells remained sensitive to lytic phage isolated from sewage. After incubation with a phage lysate derived from
P. aeruginosa
1822, anaerobic transfer of antibiotic resistance to recipients
P. aeruginosa
PS8EtBr and PS8EtBrR occurred at frequencies of 6.2 × 10
−9
and 5.0 × 10
−8
cells per plaque-forming unit, respectively. In experiments performed outside the isolator, transfer frequencies to PS8EtBr and PS8EtBrR were higher, 1.3 × 10
−7
and 6.5 × 10
−8
cells per plaque-forming unit, respectively. When
P. aeruginosa
1822 was incubated aerobically with
Escherichia coli
B in medium containing nitrate and nitrite, the maximum concentration of carbenicillin-resistant
E. coli
B reached 25% of the total
E. coli
B population. This percentage declined to 0.01% of the total
E. coli
B population when anaerobically grown
P. aeruginosa
1822 and
E. coli
B were combined and incubated in the glove box isolator. The highest concentration of the recipient population converted to antibiotic resistance occurred after 24 h of aerobic incubation, when an initially high donor/recipient ratio (>15) of cells was mixed. These data indicate that transfer of antibiotic resistance either by transduction between
Pseudomonas
spp. or by conjugation between
Pseudomonas
sp. and
E. coli
occurs under strict anaerobic conditions, although at lower frequencies than under aerobic conditions.
Evaluation of Bone Strength During Aflatoxicosis and Ochratoxicosis
Authors: Huff William E. , Doerr John A. , Hamilton Pat B. , Hamann Donald D. , Peterson Robert E. , Ciegler Alex
Published: January 2020

Young chickens were fed graded levels of aflatoxin (0, 0.625, 1.25, 2.5, 5.0, and 10.0 μg/g of diet) or ochratoxin (0, 0.5, 1.0, 2.0, 4.0, and 8.0 μg/g of diet), and the breaking strength, displacement before failure, and diameter of their tibias were determined. Breaking strength was decreased at growth inhibitory levels of aflatoxin (2.5 μg/g) and ochratoxin (2 μg/g), whereas a reduction in diameter required higher levels (5.0 and 4.0 μg/g, respectively). Bones from birds with ochratoxicosis selected to have diameters equal to control bones had lower breaking strength. In an attempt to negate mathematically the effect of decreased diameter and bias in any selection process, stress at time of failure of the bones was calculated and found to be decreased by feeding aflatoxin but not ochratoxin. Total displacement of bones before breaking was increased significantly (
P
< 0.05) by both toxins at the highest levels administered, but this increase was primarily the result of an increase in displacement from the start of failure to complete failure. Increased displacement associated with both toxicoses was equal in bones selected to be of equal diameter or in bones from the same treatment but of different diameters. However, calculation of modulus of elasticity which is corrected for diameter revealed aflatoxin had no effect whereas ochratoxin tripled the effect. These data indicate that the material properties of bones can be altered during mycotoxicoses and suggest yet another way in which mycotoxins are detrimental to animal health.
Are air-conditioning maintenance personnel at increased risk of Legionellosis?
Authors: Goldman W D , Marr J S
Published: January 2020

We surveyed by use of medical questionnaires and blood tests 21 maintenance workers involved with cleaning and servicing cooling towers and evaporative condensers at a large company to determine the frequency of pneumonia and antibody levels against Legionella pneumophila serogroup 1. The 21 high-risk workers were compared with 27 low-risk workers, persons who were not directly involved in service or maintenance for the company. The overall prevalence of titers greater than or equal to 128 for the 21 high-risk workers was 19.0% compared with 22.2% for the low-risk group. There were no significant differences in the history of pneumonia between these groups. Possible explanations for these findings are discussed.
Uric Acid-Degrading Bacteria in Guts of Termites [
Reticulitermes flavipes
(Kollar)]
Authors: Potrikus C. J. , Breznak John A.
Published: January 2020

Uricolytic bacteria were present in guts of
Reticulitermes flavipes
in populations up to 6 × 10
4
cells per gut. Of 82 strains isolated under strict anaerobic conditions, most were group N
Streptococcus
sp.,
Bacteroides termitidis
, and
Citrobacter
sp. All isolates used uric acid (UA) as an energy source anaerobically, but not aerobically, and NH
3
was the major nitrogenous product of uricolysis. However, none of the isolates had an absolute requirement for UA. Utilization of heterocyclic compounds other than UA was limited. Fresh termite gut contents also degraded UA anaerobically, as measured by
14
CO
2
evolution from [2-
14
C]UA. The magnitude of anaerobic uricolysis [0.67 pmol of UA catabolized/(gut × h)] was entirely consistent with the population density of uricolytic bacteria in situ. Uricolytic gut bacteria may convert UA in situ to products usable by termites for carbon, nitrogen, energy, or all three. This possibility is consistent with the fact that
R. flavipes
termites from UA, but they do not void the purine in excreta despite the lack of uricase in their tissues.
Rapid detection of staphylococcal thermonuclease on casings of naturally contaminated fermented sausages
Authors: Emswiler-Rose B S , Johnston R W , Harris M E , Lee W H
Published: January 2020

Staphylococcal food poisoning associated with fermented sausages has been a recurring problem. By testing for thermonuclease by direct application of sausage casing disks on the surface of thermonuclease assay agar plates, possible Staphylococcus aureus growth in fermented sausages could be detected simply and rapidly. Koupal-Deibel deoxyribonucleic acid agar was somewhat superior to toluidine blue deoxyribonucleic acid agar for thermonuclease assay of fermented sausage casings. The sensitivity of the thermonuclease casing test was comparable to that of the extraction procedure, and the thermonuclease casing test results were in complete agreement with the thermonuclease assay results by the extraction procedure. The thermonuclease casing test offers government and industry laboratories a useful screening tool which could significantly reduce the problem of staphylococcal enterotoxins in fermented sausages.
Stabilities of Clostridium botulinum type B and C toxins in ruminal contents of cattle
Authors: Kozaki S , Notermans S
Published: January 2020

Purified L (large) toxins of Clostridium botulinum type B and C are more stable than M (medium) toxins in ruminal contents of cattle. That finding suggests that the stabilities of L toxins are in part responsible for the incidence of intoxication of cattle.
Lignocellulose Mineralization by Arctic Lake Sediments in Response to Nutrient Manipulation
Authors: Federle Thomas W. , Vestal J. Robie
Published: January 2020

Mineralization of specifically labeled
14
C-cellulose- and
14
C-lignin-labeled lignocelluloses by Toolik Lake, Alaska, sediments was examined in response to manipulation of various environmental factors. Mineralization was measured by quantifying the amount of labeled CO
2
released from the specifically labeled substrates. Nitrogen (NH
4
NO
3
) and, to a greater degree, phosphorus (PO
4
−3
) additions enhanced the mineralization of white pine (
Pinus strobus
) cellulose during the summer of 1978. Nitrogen and phosphorus together had no cumulative effect. During the summer of 1979, nitrogen or phosphorus alone had only a slight stimulatory effect on the mineralization of a sedge (
Carex aquatilis
) cellulose; however, together, they had a dramatic effect. This variable response of mineralization to nutrient addition between 1978 and 1979 was probably attributable to year-to-year variation in nutrient availability within the lake. Cellobiose addition and oxygen depletion inhibited the amount of pine cellulose mineralized. Whereas addition of nitrogen to oxygen-depleted treatments had limited effect, addition of phosphorus resulted in mineralizations equal to or greater than that of the controls. Nitrogen had no effect on mineralization of pine or
Carex
lignins. Phosphorus, however, inhibited mineralization of both lignins. With
Carex
lignin, the phosphorus inhibition occurred at a concentration as low as 0.1 μM. The antagonistic role of phosphorus in cellulose and lignin mineralizations may be of significance in understanding the increased proportion of lignin relative to cellulose in decomposing litter.
Effect of disinfectants on pathogenic free-living amoebae: in axenic conditions
Authors: Cursons R T , Brown T J , Keys E A
Published: January 2020

The amoebicidal properties of chlorine, chlorine dioxide, ozone, and deciquam 222 were examined in axenic conditions. Naegleria spp. were found to be more sensitive to chlorine and chlorine dioxide than Acanthamoeba spp. No marked difference in sensitivity to ozone or deciquam 222 could be detected between the pathogenic (A-1) and nonpathogenic (1501) strains of Acanthamoeba and the pathogenic (MsT) and nonpathogenic (P1200f) strains of Naegleria. Methods of disinfection are discussed with reference to suitability of the disinfectants to real conditions.
Interactions and Survival of Enteric Viruses in Soil Materials
Authors: Sobsey Mark D. , Dean Cheryl H. , Knuckles Maurice E. , Wagner Ray A.
Published: January 2020

There were marked differences in the abilities of eight different soil materials to remove and retain viruses from settled sewage, but for each soil material the behavior of two different viruses, poliovirus type 1 and reovirus type 3, was often similar. Virus adsorption to soil materials was rapid, the majority occurring within 15 min. Clayey materials efficiently adsorbed both viruses from wastewater over a range of pH and total dissolved solids levels. Sands and organic soil materials were comparatively poor adsorbents, but in some cases their ability to adsorb viruses increased at low pH and with the addition of total dissolved solids or divalent cations. Viruses in suspensions of soil material in settled sewage survived for considerable time periods, despite microbial activity. In some cases virus survival was prolonged in suspensions of soil materials compared to soil-free controls. Although sandy and organic soil materials were poor virus adsorbents when suspended in wastewater, they gave ≥95% virus removal from intermittently applied wastewater as unsaturated, 10-cm-deep columns. However, considerable quantities of the retained viruses were washed from the columns by simulated rainfall. Under the same conditions, clayey soil material removed ≥99.9995% of the viruses from applied wastewater, and none were washed from the columns by simulated rainfall.
Comparison of Bacterial Extracellular Polymer Extraction Methods
Authors: Brown Melanie J. , Lester John N.
Published: January 2020

Five different bacterial extracellular polymer extraction methods and a combination of two of these methods were compared on cultures of activated sludge, synthetic activated sludge, and
Klebsiella aerogenes
. High-speed centrifugation was the most effective extraction method for the
K. aerogenes
culture, based on the comparatively small amount of cell disruption and the relatively high extracellular polymer yield. Steaming treatment was the most effective extraction method for the activated sludges, since it released a significant quantity of extracellular polymers from the flocs and caused less cellular disruption than ethylenediaminetetraacetic acid and sodium hydroxide treatments. Sodium hydroxide treatment caused extensive disruption in all cultures. Ultrasonication released low concentrations of extracellular polymers from all cultures. However, it caused no significant cell disruption and therefore may be useful as a preliminary treatment in conjunction with another extraction method.
Thermothrix thiopara:
Growth and Metabolism of a Newly Isolated Thermophile Capable of Oxidizing Sulfur and Sulfur Compounds
Authors: Brannan Daniel K. , Caldwell Douglas E.
Published: January 2020

Thermothrix thiopara
is isolated from hot sulfur springs. It occurs in situ at a temperature of 72�C, a pH of 7.0, and an HS
-
concentration of 17.4 μmol/liter (0.8 ppm). The organism was capable of autotrophic growth. Sulfite, sulfur, and polythionates were formed and subsequently degraded to sulfate during growth with thiosulfate as the sole energy source. Thiosulfate was oxidized by the polythionate pathway, and the stoichiometry of growth on thiosulfate was determined. The organism was also capable of heterotrophic growth in amino acids and simple sugars. A source of reduced sulfur (methionine, glutathione) was required for heterotrophic growth. Growth occurred aerobically or anaerobically with nitrate as a terminal oxidant. Both nitrous oxide and dinitrogen were produced. At 73�C the maximum autotrophic growth rate in batch culture using thiosulfate was 0.56 generation per h. Under the same conditions in continuous culture, washout occurred at a dilution rate of 0.3 to 0.4 per h, corresponding to a cellular growth rate of 0.43 to 0.58 generation per h. This was nearly three times the growth rate for
Thiobacillus denitrificans. T. thiopara
is gram negative. It was also found to be both lysozyme and penicillin susceptible. As a result, this organism cannot be considered an archaebacterium.
Effects of pesticides on the fatty acid and phospholipid composition of Escherichia coli
Authors: Rosas S B , Secco M , Ghittoni N E
Published: January 2020

Cells of Escherichia coli contained an altered phospholipid and fatty acid composition when grown in the presence of some pesticides. Whereas parathion increased the concentration of all phospholipid species without changes in their polar head groups. DDT (dichlorodiphenyltrichloroethane) decreased the proportion of neutral serine-derived phosphatides and dieldrin decreased the proportion of negatively charged phospholipids. The saturated/unsaturated plus cyclopropane fatty acid ratio was increased in all cases. The changes suggested that cells adapted their membrane lipids to compensate for the presence of pesticides in the environment.
Comparative inactivation of viruses by chlorine
Authors: Engelbrecht R S , Weber M J , Salter B L , Schmidt C A
Published: January 2020

The kinetics of inactivation of six enteric viruses plus simian virus 40 and Kilham rat virus by free available chlorine was studied under carefully controlled laboratory conditions. It was found that the different virus types demonstrated a wide range of susceptibility to chlorine disinfection. The rate of inactivation was greater at pH 6 than at pH 10; however, the relative susceptibilities of the different viruses were affected differently by a change in pH, suggesting that the pH influenced both the species of chlorine present and the susceptibility of the different viruses to chlorine. The presence of potassium chloride also affected the susceptibility of viruses to chlorine.
Microbial Degradation of a Macrotetrolide Miticide in Soil
Authors: Sasaki Hiroshi , Suzuki Koji , Ichikawa Tadashi , Sawada Mikio , Iwane Yoshitaka , Ando Kunio
Published: January 2020

Macrotetrolide, a miticide consisting of tetranactin, trinactin, and dinactin, was readily biodegradable and hence did not accumulate in soil. [
U
-
14
C]macrotetrolide was rapidly degraded via its constituent hydroxycarboxylic acids to carbon dioxide and water. In culture media, however, the mixture was hydrolyzed to homononactic and nonactic acids by three strains of
Bacillus
sp. and two of
Micrococcus
sp. The latter strains were able to hydrolyze 500 μg of the antibiotic per ml within a few days and to grow in the presence of 4,000 μg of the antibiotic per ml. However, they were unable to assimilate the constituent acids which accumulated in the culture medium.
Improved Filtration Technique for Concentrating and Harvesting Bacteria
Authors: Tanny Gerald B. , Mirelman David , Pistole Thomas
Published: January 2020

An improved technique is described for the filtrative concentration and harvesting of bacterial cultures. A pleated tangential flow filtration unit containing 1,000 cm
2
of 0.2-μm-pore-size microporous membrane was used to rapidly (30 to 50 min) reduce the volume of 5 liters of bacterial culture of approximately 10
9
cells per ml to 0.2 to 0.5 liters of concentrated bacterial suspension. The effects of cell concentration, filtration pressure, and tangential flow rate were examined with respect to the rate of concentration and cell viability. Recovery efficiencies were between 60 and 75%, with no apparent impairment of organism viability. Cell concentration exerted the predominant effect on the filtration rate.
Inactivation of Mycobacterium bovis in meat products
Authors: Merkal R S , Whipple D L
Published: January 2020

The time-temperature combinations necessary to destroy Mycobacterium bovis in meat products were determined. In any given time, M. bovis was destroyed at temperatures 6 to 7 degrees C (ca. 12 degrees F) lower than those necessary for destruction of members of the Mycobacterium avium-Mycobacterium intracellulare complex. Hence, any processing heat adequate to kill M. avium-M. intracellulare-complex organisms will provide a very large safety factor with respect to M. bovis. Benzalkonium chloride treatment of wiener specimens for cultural examination effectively destroyed the normal flora of wiener emulsion without reducing the numbers of M. bovis. Treatment with a phenolic disinfectant followed by formaldehyde vapor was effective in disinfecting equipment contaminated with meat emulsion containing M. bovis.
Variability in gas production by Escherichia coli in enrichment media and its relationship to pH
Authors: Meadows P S , Anderson J G , Patel K , Mullins B W
Published: January 2020

Variability in gas production in multiple subcultures of Escherichia coli was assessed in two selective enrichment media and in lactose peptone water. Considerable variability occurred with all media at 37 and 44 degrees C. Addition of buffer increased gas production and decreased variability. The relationships between pH, growth, and gas production were complex. In buffered media, viable counts increased by 269 x 10(6) to 382 x 10(6)/U of pH fall, whereas in unbuffered media, they increased by 9.45 x 10(6) to 30.37 x 10(6)/U of pH fall. In buffered and unbuffered media, pH fell as gas production rose. However, variability in gas production among individual subcultures was not associated with changes in pH.
Short-Term Effects of South Louisiana and Kuwait Crude Oils on Glucose Utilization by Marine Bacterial Populations
Authors: Alexander Steve K. , Schwarz John R.
Published: January 2020

Two crude oils, South Louisiana and Kuwait, were examined for their impact on glucose utilization by bacterial populations from the Gulf of Mexico. The uptake and mineralization of [
U
-
14
C]glucose was assayed after a 4- to 23-h exposure to various concentrations of added crude oil (0, 0.001, 0.01, and 0.1% [vol/vol]). The effects of oil were determined in a total of 15 sediment and 13 water samples collected from offshore, open-bay, and salt marsh environments. The utilization of glucose by bacterial populations usually was not affected by added oil; in 10 sediment and 11 water samples, oil had no significant effect on either glucose uptake or mineralization. Stimulation by oil was recorded in four sediment samples. Oil inhibition occurred in one sediment and two water samples, but only in the presence of the highest concentration of added oil, i.e., 0.1%. Our data suggest that short-term exposure to either South Louisiana or Kuwait crude oil, even at 0.1%, usually has no toxic effect on glucose utilization by marine bacterial populations.
Effect of Estuarine Sediment pH and Oxidation-Reduction Potential on Microbial Hydrocarbon Degradation
Authors: Hambrick Gordon A. , DeLaune Ronald D. , Patrick W. H.
Published: January 2020

Microbial mineralization rates of two petroleum hydrocarbons, as affected by pH and oxidation-reduction potential, were determined in a Barataria Bay, Louisiana, sediment using
14
C-labeled hydrocarbons. Hydrocarbon mineralization rates were inferred from the activity of respired
14
CO
2
. Sediment pH and oxidation-reduction potential were important factors in governing the population of hydrocarbon-degrading microorganisms in the sediment and subsequent mineralization rates. Highest mineralization rates occurred at pH 8.0, and the lowest occurred at pH 5.0. At all pH levels mineralization decreased with decreasing oxidation-reduction potential (i.e., increasing sediment anaerobiosis). Generally, mineralization rates for octadecane were greater than those for naphthalene. Aerobic microorganisms in the oxidized sediment were more capable of degrading hydrocarbons than anaerobic microorganisms in reduced sediment of the same pH.
Inactivation of poliovirus I (Brunhilde) single particles by chlorine in water
Authors: Sharp D G , Leong J
Published: January 2020

Like the Mahoney strain, the Brunhilde strain of poliovirus aggregated slowly in dilute phosphate-carbonate buffer at pH 6 but not at all at or above pH 7. Infectivity decreased at rates approximately proportional to the concentration of free chlorine present at pH 6 over the entire range of 5 to 40 micrometer. The addition of 0.1 M NaCl to the buffer increased the rate about twofold, but this strain was still twice as resistant as the Mahoney strain. At pH 10, inactivation was much slower than at pH 6, but when 0.1 M NaCl was added, the rate was increased 31-fold, making the OCl- at pH 10 over three times more effective than HOCl at pH 6.
Cholesterol as a limiting factor in the growth of Mycoplasma pneumoniae
Authors: Johnson J K , Somerson N L
Published: January 2020

Ultracentrifugation was used to separate three commercial lots of bovine serum fraction (BSF) into components designed to contain lipoproteins. Each BSF lot and component was tested for ability to support the growth of tree strains of Mycoplasma pneumoniae. In general, the level of growth-promoting activity corresponded to the amount of cholesterol present in the BSF or BSF components rather than to the amount or type of lipoprotein Cholesterol was the limiting nutritional factor of BSF with low growth-promoting activity. The addition of cholesterol and bovine serum albumin to BSF with low activity resulted in growth equal to or greater than that observed for BSF with high growth-promoting activity. When cholesterol was added to agar medium containing BSF of low activity, mycoplasma colonies were greater in number, possessed larger mean diameters, and had centers that were more distinct than those observed when this BSF was used alone. Variability in growth-promoting actions of commercial lots of BSF was eliminated by increasing their cholesterol content to an optimum level. An adjustment of the cholesterol and albumin levels of any serum product used in culture media may provide a simple convenient method to improve growth and isolation of mycoplasmas.
Bacteria Associated with the Gut Tract of Larval Stages of the Aquatic Cranefly
Tipula abdominalis
(Diptera; Tipulidae)
Authors: Klug M. J. , Kotarski S.
Published: January 2020

Scanning electron microscopy, light microscopy, and direct isolations were used to examine the distribution and diversity of bacteria in the gut tracts of larval stages of
Tipula abdominalis
. The animal had an enlarged hindgut which housed a diverse bacterial community in the lumen and directly attached to the gut wall. Distinct localization was noted, with the most dense and most diverse community anterior to the rectum. A distinct architecture of bacteria occurred in this region, characterized by a layering or a “weblike” array of filamentous bacteria overlying mats of bacteria closely associated with the gut wall. Although morphological diversity was high in the hindgut, filamentous bacteria were the dominant morphology observed. The attached microbiota, sloughed during ecdysis, recolonized to the same density and diversity observed before the molt. The majority of the isolatable bacterial types were facultatively anaerobic. The distinct localization and attached nature of the hindgut bacteria and the recolonization after each molt suggest they are indigenous to this region of the gut tract.

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Effect of different growth conditions on the discrimination of three bacteria by pyrolysis gas-liquid chromatography
Authors: Gutteridge C S , Norris J R
Published: January 2020

High-resolution pyrolysis gas-liquid chromatography was applied to three bacteria (Escherichia coli NCTC 9001, Pseudomonas putida (NCIB 9494, and Staphylococcus aureus NCTC 8532) grown under a variety of conditions. Changing the culture medium drastically altered the quantitative aspects of the pyrograms of all three organisms, but the effects of culture time and incubation temperature were less severe. Mathematical analysis of the relative peak heights showed that four peaks could be used to discriminate the three bacteria however they were cultured.
Factors affecting inactivation of Moraxella-Acinetobacter cells in an irradiation process
Authors: Firstenberg-Eden R , Rowley D B , Shattuck G E
Published: January 2020

The effect of various stages of the irradiation processing of beef on the injury and inactivation of radiation-resistant Moraxella-Acinetobactor cells was studied. Moraxella-Acinetobacter cells were more resistant to heat inactivation and injury when heated in meat with salts (0.75% NaCl and 0.375% sodium tripolyphosphate) then in meat without salts. These salts had no effect on radiation resistance. Both radiation- and heat-injured cells were unable to form colonies at 30 degrees C in plate count agar containing 0.8% NaCl. Neither unstressed nor heat-stressed cells were able to multiply in minced beef incubated at 30 degrees C for 12 h. Only after the beef was diluted 1:10 with peptone water were the heat-injured cells able to repair and eventually multiply. Heated cells were more sensitive to radiation inactivation and injury than unheated cells. After repair, the cells regained their resistance to both NaCl and irradiation. Freezing and storage at -40 degrees C for 14 days had only a slight effect on either unstressed or heat-stressed cells.
Restriction and Modification in Group N Streptococci: Effect of Heat on Development of Modified Lytic Bacteriophage
Authors: Sanders M. E. , Klaenhammer T. R.
Published: January 2020

The appearance of lytic bacteriophage against newly introduced starter strains used during commercial cheese manufacture occurs rapidly, and their origin is not well understood. In this study, members of the group N streptococci were examined for the presence of bacteriophage restriction and modification systems. Two streptococcal phages from
Streptococcus cremoris
TR and
Streptococcus lactis
C2 (phage designations tr and c2) showed restricted lytic development on
S. cremoris
799 and KH, respectively. Efficiency of plaquing was 1.9 × 10
−7
for tr plaqued on 799 and 2.1 × 10
−7
for c2 plaqued on KH. After passage through the restrictive hosts, these phages demonstrated high lytic ability for formerly restrictive hosts. Stress of the restrictive host strains at temperatures of 40 to 50°C resulted in a significant increase in the efficiency of plaquing of restricted bacteriophages. Elevated temperatures are encountered during commercial cheese manufacture. The results suggested that the temporary loss of host restriction activity with the resulting modification of nonspecific bacteriophage may contribute directly to the appearance of lytic phage against new starter strains.
Effect of Rice Plants on Nitrogenase Activity of Flooded Soils
Authors: Habte Mitiku , Alexander Martin
Published: January 2020

In samples of flooded soil containing blue-green algae (cyanobacteria), the presence of rice plants did not influence the nitrogenase activity of the algae. Nitrogenase activity of heterotrophic bacteria was enhanced by the presence of rice plants, but this activity was not affected by changes in plant density. The rate of nitrogen fixation in the rhizosphere, however, varied significantly among the 16 rice varieties tested. A simple method was devised to test the nitrogen-fixing activity in the root zone of rice varieties, and data were obtained showing marked differences in the activities of the 16 varieties. In tests of two varieties with dissimilar rates of nitrogen fixation in their rhizospheres, the variety which had the greater root weight and lesser shoot weight and which supported greater methane formation had the greater nitrogenase activity.
Production of NO
2
-
and N
2
O by Nitrifying Bacteria at Reduced Concentrations of Oxygen
Authors: Goreau Thomas J. , Kaplan Warren A. , Wofsy Steven C. , McElroy Michael B. , Valois Frederica W. , Watson Stanley W.
Published: January 2020

Pure cultures of the marine ammonium-oxidizing bacterium
Nitrosomonas
sp. were grown in the laboratory at oxygen partial pressures between 0.005 and 0.2 atm (0.18 to 7 mg/liter). Low oxygen conditions induced a marked decrease in the rate for production of NO
2
-
, from 3.6 × 10
−10
to 0.5 × 10
−10
mmol of NO
2
-
per cell per day. In contrast, evolution of N
2
O increased from 1 × 10
−12
to 4.3 × 10
−12
mmol of N per cell per day. The yield of N
2
O relative to NO
2
-
increased from 0.3% to nearly 10% (moles of N in N
2
O per mole of NO
2
-
) as the oxygen level was reduced, although bacterial growth rates changed by less than 30%. Nitrifying bacteria from the genera
Nitrosomonas, Nitrosolobus, Nitrosospira
, and
Nitrosococcus
exhibited similar yields of N
2
O at atmospheric oxygen levels. Nitrite-oxidizing bacteria (
Nitrobacter
sp.) and the dinoflagellate
Exuviaella
sp. did not produce detectable quantities of N
2
O during growth. The results support the view that nitrification is an important source of N
2
O in the environment.
Limulus amoebocyte lysate assay for detection and quantitation of endotoxin in a small-volume parenteral product
Authors: Tsuji K , Steindler K A , Harrison S J
Published: January 2020

A Limulus amoebocyte lysate gel-clotting method for the determination of endotoxin in a small-volume parenteral product has been described. Sample dilution with 0.1 M potassium phosphate monobasic buffer (pH 8.0) effectively eliminated assay interference, whereas dilution with water did not. The threshold pyrogenic dose for Escherichia coli EC-2 and O127:B8 endotoxins was determined to be 1.0 ng of endotoxin per kg of body weight. Not more than 1.0 ng of endotoxin (the threshold pyrogenic dose) per the highest recommended human dose or the USP pyrogen test dose per kg of body weight, whichever dose is more stringent, is a logical limit for the quantity of bacterial endotoxin in small-volume parenteral products. Excellent correlation was attained when this criterion was used to compare the Limulus amoebocyte lysate assay with the USP pyrogen test.
Development of ethanol tolerance in Clostridium thermocellum: effect of growth temperature
Authors: Herrero A A , Gomez R F
Published: January 2020

The growth of Clostridium thermocellum ATCC 27405 and of C9, an ethanol-resistant mutant of this strain, at different ethanol concentrations and temperatures was characterized. After ethanol addition, cultures continued to grow for 1 to 2 h at rates similar to those observed before ethanol was added and then entered a period of growth arrest, the duration of which was a function of the age of inocula. After this period, cultures grew at an exponential rate that was a function of ethanol concentration. The wild-type strain showed a higher energy of activation for growth than the ethanol-tolerant derivative. The optimum growth temperature of the wild type decreased as the concentration of the ethanol challenge increased, whereas the optimum growth temperature for C9 remained constant. The results are discussed in terms of what is known about the effects of ethanol and temperature on membrane composition and fluidity.
Propionate-Degrading Bacterium,
Syntrophobacter wolinii
sp. nov. gen. nov., from Methanogenic Ecosystems
Authors: Boone David R. , Bryant Marvin P.
Published: January 2020

A new genus and species of a nonmotile gram-negative rod,
Syntrophobacter wolinii
, is the first bacterium described which degrades propionate only in coculture with an H
2
-using organism and in the absence of light or exogenous electron acceptors such as O
2
, sulfate, or nitrate. It was isolated from methanogenic enrichments from an anaerobic municipal sewage digestor, using anaerobic roll tubes containing a medium with propionate as the energy source in association with an H
2
-using, sulfate-reducing
Desulfovibrio
sp. which cannot utilize fatty acids other than formate.
S. wolinii
produced acetate and, presumably, CO
2
and H
2
(or formate) from propionate. In media without sulfate and with
Methanospirillum hungatei
, a methanogen that uses only H
2
-CO
2
or formate as an energy source, acetate, methane, and, presumably, CO
2
were produced from propionate and only small amounts of
Desulfovibrio
sp. were present. Isolation in coculture with the methanogen was not successful.
S. wolinii
does not use other saturated fatty acids as energy sources.
Penicillium rubrum and Penicillium biforme, new sources of rugulovasines A and B
Authors: Dorner J W , Cole R J , Hill R , Wicklow D , Cox R H
Published: January 2020

An isolate of Penicillium biforme Thom produced rugulovasines A and B. An isolate of Penicillium rubrum Stoll produced rugulovasines A and B and also chlororugulovasines A and B. Both fungi represent new sources of the rugulovasines.
Response of N
2
-Fixing Cyanobacteria to Salt
Authors: Tel-Or Elisha
Published: January 2020

The effect of salt on photosynthetic activity, acetylene reduction, and related activities was examined in two species of cyanobacteria,
Nostoc muscorum
and
Calothrix scopulorum
. Photosynthesis was more resistant to high salt concentration than was N
2
fixation. The salt resistance of both activities increased after a period of exposure of the cells to salinity. The transfer of electrons via ferredoxin and ferredoxin-nicotinamide adenine dinucleotide phosphate reductase was found to be extremely sensitive to salt. In comparison, the transfer of reducing power by glucose-6-phosphate dehydrogenase, isocitric dehydrogenase, and photosystem 1 was less affected by NaCl, whereas glutamine synthetase exhibited higher tolerance to salt.
Purification and characterization of polyethylene glycol dehydrogenase involved in the bacterial metabolism of polyethylene glycol
Authors: Kawai F , Kimura T , Tani Y , Yamada H , Kurachi M
Published: January 2020

Polyethylene glycol (PEG) dehydrogenase in crude extracts of a PEG 20,000-utilizing mixed culture was purified 24 times by precipitation with ammonium sulfate, solubilization with laurylbetaine, and chromatography with diethylamino-ethyl-cellulose, hydroxylapatite, and Sephadex G-200. The purified enzyme was confirmed to be homogeneous by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The molecular weight of the enzyme, which appeared to consist of four identical subunits, was 2.4 X 10(5). The enzyme was stable below 35 degrees C and in the pH range of 7.5 to 9.0. The optimum pH and temperature of the activity were around 8.0 and 60 degrees C, respectively. The enzyme did not require any metal ions for activity and oxidized various kinds of PEGs, among which PEG 6,000 was the most active substrate. The apparent Km values for tetraethylene glycol and PEG 6,000 were about 10.0 and 3.0 mM, respectively.
Mineralization of Detrital Lignocelluloses by Salt Marsh Sediment Microflora
Authors: Maccubbin A. E. , Hodson Robert E.
Published: January 2020

Specifically radiolabeled
14
C-(cellulose)-lignocellulose and
14
C-(lignin)-lignocellulose were isolated from labeled cuttings of
Spartina alterniflora
(cordgrass) and
Pinus elliottii
(slash pine). These were used to estimate the rates of mineralization to CO
2
of lignocelluloses of estuarine and terrestrial origin in salt marsh estuarine sediments. The lignin moiety of pine lignocellulose was mineralized 10 to 14 times more slowly than that of
Spartina
lignocellulose, depending on the source of inoculum. Average values for percent mineralization after 835 h of incubation were 1.4 and 13.9%, respectively. For
Spartina
lignocellulose, mineralization of the cellulose moiety was three times faster than that of the lignin moiety. Average values for percent mineralization after 720 h of incubation were 32.1 and 10.6%, respectively. Lignocellulose and lignin contents of live pine and
Spartina
plants were analyzed and found to be 60.7 and 20.9%, respectively, for pine and 75.6 and 15.1%, respectively, for
Spartina
.
Species Composition and Barotolerance of Gut Microflora of Deep-Sea Benthic Macrofauna Collected at Various Depths in the Atlantic Ocean
Authors: Ohwada Kouichi , Tabor Paul S. , Colwell Rita R.
Published: January 2020

The bacterial flora of marine animals collected at depths of 570 to 2,446 m was examined for population size and generic composition, and the barotolerant characteristics of selected bacterial isolates were determined. Total numbers of culturable, aerobic, heterotrophic bacteria were found to be low in animals collected at the greatest ocean depths sampled in this study.
Vibrio
spp. were predominant in 10 of 15 samples examined, and
Photobacterium
spp. and yeasts were the major components of the remainder.
Pseudomonas, Achromobacter
, and
Flavobacterium
spp. comprised minor components of the gut flora of deep-sea fish. Forty-six pure cultures isolated from samples of seven animals were tested for growth or viability after incubation for 1 week under pressures ranging from 100 to 750 atm. Strains of bacteria isolated from samples of fish intestine were more barotolerant than those from the stomach (
P
<0.01). When incubated at a pressure of 600 atm, viability of bacterial cultures originally isolated from fish caught at a depth of 570 m was significantly decreased in comparison with viability of cultures from animals caught at depths of 1,393 and 2,446 m (
P
<0.01). From results of this study, it is concluded that the gut microflora of animals that dwell in the deeper regions of the ocean are adapted to an increased hydrostatic pressure environment, that is, the gut microflora is less inhibited by elevated hydrostatic pressure with increasing depth from which the host animal was collected.
R-plasmid transfer frequencies from environmental isolates of Escherichia coli to laboratory and fecal strains
Authors: Shaw D R , Cabelli V J
Published: January 2020

Multiple-drug-resistant strains of Escherichia coli were isolated from the water at an estuarine site. They represented about 8.3% of the total E. coli population. Fifty-five strains, representing each of the 32 resistance patterns identified, were mated with an E. coli K-12 F- strain. Matings were performed on membrane filters, and the cells were washed to remove any colicins produced by the donors. Thirty-one strains, about 5% of the mean E. coli density in the samples, transferred drug resistance and, hence, posessed conjugative R plasmids. Of these, 80% transferred drug resistance at a frequency of about 10(-4) or less. Nine environmental R+ strains were mated with three fecal recipients. The R-plasmid transfer frequencies to the fecal strains from the environmental donors correlated well with those from a derepressed K-12 R+ laboratory donor. The R+ X K-12 F- lac- transconjugants from 16 environmental strains were "backcrossed" to a lac+ K-12 F- strain. All transfer frequencies were higher in the backcrosses than in the original matings from the environmental donor. Furthermore, 7 of 13 different transconjugants, which accepted plasmids at repressed frequencies of less than 10(-3), donated them at frequencies greater than 10(-2). This suggests that these were derepressed plasmids in a repressed host.
Appraisal of Media and Methods for Assay of Bacteriophages of Lactic Streptococci
Authors: Keogh Barbara P.
Published: January 2020

To assess the relative merits of tryptone yeast extract agar, the same medium unbuffered, and medium M17 for the assay of nine bacteriophages of lactic streptococci, comparative plaque counts were made with an overlay of 3 or 9 ml. Four of the phages exhibited no significant difference in plating efficiency between media. The effect of overlay volume varied from strain to strain and was different for different media. The 3-ml overlay created suboptimal atmospheric conditions for those strains which had a special requirement for CO
2
. The use of a 9-ml overlay obviated the need to incubate plates under CO
2
and overcame the problems related to special calcium requirements when tryptone yeast extract agar was used. The organic buffer (disodium β-glycerophosphate) was inhibitory to
Streptococcus cremoris
ML1 and showed no advantage over the inorganic phosphate buffer (K
2
HPO
4
) for most other strains.
Attack on Lignified Grass Cell Walls by a Facultatively Anaerobic Bacterium
Authors: Akin Danny E.
Published: January 2020

A filamentous, facultatively anaerobic microorganism that attacked lignified tissue in forage grasses was isolated from rumen fluid with a Bermuda grass-containing anaerobic medium in roll tubes. The microbe, designated 7-1, demonstrated various colony and cellular morphologies under different growth conditions. Scanning electron microscopy revealed that 7-1 attacked lignified cell walls in aerobic and anaerobic culture. 7-1 predominately degraded tissues reacting positively for lignin with the chlorine-sulfite stain (i.e., sclerenchyma in leaf blades and parenchyma in stems) rather than the more resistant acid phloroglucinol-positive tissues (i.e., lignified vascular tissue and sclerenchyma ring in stems), although the latter tissues were occasionally attacked. Turbidimetric tests showed that 7-1 in anaerobic culture grew optimally at 39°C at a pH of 7.4 to 8.0. Tests for growth on plant cell wall carbohydrates showed that 7-1 grew on xylan and pectin slowly in aerobic cultures but not with pectin and only slightly with xylan in anaerobic culture. 7-1 was noncellulolytic as shown by filter paper tests. The microbe used the phenolic acids sinapic, ferulic, and
p
-coumaric acids as substrates for growth; the more highly methoxylated acids were used more effectively.
In vitro metabolism of T-2 toxin in rats
Authors: Yoshizawa T , Swanson S P , Mirocha C J
Published: January 2020

T-2 toxin was rapidly converted in the 9,000 X g supernatant fraction of rat liver homogenate into HT-2 toxin, T-2 tetraol, and two unknown metabolites designated as TMR-1 and TMR-2. TMR-1 was characterized as 4-deacetylneosolaniol (15-acetoxy-3 alpha, 4 beta, 8 alpha-trihydroxy-12,13-epoxytrichothec-9-ene) by spectroscopic analyses. Since the same metabolites were also obtained from HT-2 toxin used as substrate, it was concluded that T-2 toxin was hydrolyzed preferentially at the C-4 position to give HT-2 toxin, which was then metabolized to T-2 tetraol via 4-deacetylneosolaniol. In addition to HT-2 toxin, 4-deacetylneosolaniol and T-2 tetraol, a trace amount of neosolaniol was transformed from T-2 toxin by rat intestinal strips. In vitro metabolic pathways for T-2 toxin in rats are proposed.
Relative effects of bacterial and protozoan predators on survival of Escherichia coli in estuarine water samples
Authors: McCambridge J , McMeekin T A
Published: January 2020

The relative effect of protozoan and bacterial predators on the survival of Escherichia coli in estuarine water samples was examined. Predacious protozoa exerted their major influence on E. coli destruction during the first 2 days of a 10-day-decline period. Inhibition of protozoa after day 2 had little effect on E. coli survival. Bacterial predators also contributed to E. coli destruction but in natural estuarine water samples were maintained at lower levels due to "grazing" by predacious protozoa.
Incidence of marine bdellovibrios lytic against Vibrio parahaemolyticus in Chesapeake Bay
Authors: Williams H N , Falkler W A , Shay D E
Published: January 2020

The incidence of marine bdellovibrios at selected sampling sites in the Chesapeake Bay during the months of June 1978 and 1979 was studied. Bdellovibrios were isolated from eight of nine sampling stations in the bay. Higher numbers than previously reported with sea or ocean water were recovered in the midregion of the bay.
Fungal Pathogen of
Cladophora glomerata
(Chlorophyta)
Authors: Bott Thomas L. , Rogenmuser Kurt
Published: January 2020

A strain of
Acremonium kiliense
(
Fungi Imperfecti
) produced a water-soluble, dialyzable, heat-stable agent that rendered
Cladophora glomerata
(Chlorophyta) chlorotic and inhibited its growth.
Plasmid-controlled mercury biotransformation by Clostridium cochlearium T-2
Authors: Pan-Hou H S , Hosono M , Imura N
Published: January 2020

A strain of Clostridium cochlearium having methylmercury-decomposing ability was isolated. The ability was cured by the treatment with acridine dye and recovered by the conjugation of the cured strain with the parent strain. The cured strain then showed the activity to methylate mercuric ion as previously reported (M. Yamada and K. Tonomura, J. Ferment. Technol. 50:159-166, 1971). These results and the agarose gel electrophoretic pattern of the deoxyribonucleic acids from the lysates indicate a possible role of plasmids in controlling the mercury biotransformation of the two opposite directions in a single bacterial strain: methylation in the absence of the plasmid and demethylation in the presence of it. A possible mechanism for mercury resistance involving hydrogen sulfide is discussed.