bluuebunny/crossref_metadata_2025 huggingface dataset:
Method of soil column preparation for the evaluation of viral transport
Authors: Funderburg S W , Moore B E , Sorber C A , Sagik B P
Published: January 2020

A method for packing soil columns to investigate viral transport phenomena is described. The columns were 10 cm in diameter and ranged from 33 to 100 cm in length. Field conditions of the soil, including bulk density and profile, were reproduced in columns. Ionic gradients resulting from sequential applications of wastewater and distilled water affected the movement of poliovirus I (Chat) through soil. Compared with 33-cm- and 66-cm-length columns, lower concentrations of infectious virions were observed in the percolates from 100-cm soil columns. These results may be attributed to the greater pore volume in the longer columns (the greater volume of soil contained in these columns), whereas the volume of liquid applied was constant for all columns.
Membrane filter procedure for enumeration of Aeromonas hydrophila in fresh waters
Authors: Rippey S R , Cabelli V J
Published: January 2020

A membrane filter method (mA) for the enumeration of Aeromonas hydrophila in natural water samples was developed. The complex, primary medium employs trehalose as a fermentable carbohydrate and ampicillin and ethanol as selective inhibitors. After 20 h of incubation at 37 degrees C, an in situ mannitol fermentation test followed by an in situ oxidase test is used to further differentiate A. hydrophila from other aquatic and terrestrial microorganisms present in freshwaters. The primary medium decreases background microbial growth by about two orders of magnitude. The recoveries on mA medium from suspensions of A. hydrophila prepared from pure cultures and held for 24 h at 15 degrees C exceeded 95% of the recoveries on brain-heart infusion agar spread plates. The confirmation rate for colonies designated A. hydrophila was 98%, whereas 11% of the presumptively negative colonies were, in fact, A. hydrophila. Recoveries of A. hydrophila from fresh, surface water samples exceeded recoveries by the other methods examined.
Protein-to-wet weight relationships in supragingival plaques from caries-prone tooth surfaces
Authors: Gilmour M N , Turner G , Krenzer A K , Zahn L B , Curzon J A
Published: January 2020

The ratio of protein to wet weight in unpooled samples of supragingival plaques from sound and carious tooth surfaces was studied. Protein was assayed by a procedure developed for the study, in order to achieve a sensitivity of 1 microgram with minimum effects upon quantitation from protein composition and nonprotein components. Ratios of protein to wet weight in plaque specimens from caries-free surfaces were almost equally distributed into two main categories of 9.4% and 6.5%. Corresponding values for specimens from carious surfaces were 9.1% and 5.0%. The occurrence of high and of low values among samples from each type of surface indicated that the plaques differed quantitatively in protein, water, or a nonprotein component, possibly extracellular polysaccharide. Although compositional differences between plaques from the two types of surfaces were indicated by the lower ratios of 6.5% from noncarious and 5.0% from carious surfaces, they were not indicated by the higher ratio values, which were similar. These results suggest either that protein-to-wet weight ratios are not related to caries, or that the ratio values are related to caries for some but not all types of plaques.
Exohemagglutinins: new products of vibrios
Authors: Oishi K , Yokoshima S , Tomiyama T , Aida K
Published: January 2020

A number of vibrio strains isolated from marine water produced high units of phytohemagglutinin-like agglutinins. Sugar specificity of the hemagglutinins was different from that of the sugar-binding bacterial toxins and that of the sugar-binding pili on the bacterial cell surfaces.
Glutamate Functions in Osmoregulation in a Marine Bacterium
Authors: Makemson J. C. , Hastings J. W.
Published: January 2020

Beneckea harveyi,
growing in either minimal or complex media increased the total amino acid pool with increasing salinity of the medium. Glutamate was the predominate amino acid involved.
Xylose, Arabinose, and Rhamnose Fermentation by
Bacteroides ruminicola
Authors: Turner Keith W. , Roberton Anthony M.
Published: January 2020

Metabolism and growth yields of
Bacteroides ruminicola
grown on
d
-xylose,
l
-arabinose, and
l
-rhamnose were studied. Growth yields were 62, 68, and 35.5 g (dry weight) per mol of carbohydrate fermented after correction for storage polysaccharide. Experiments with [1-
14
C]arabinose indicated that pentose was fermented by a pentose phosphate cycle plus glycolysis, with some indication of a minor phosphoketolase-type pathway. The product ratios from pentose were similar to those previously described for hexose. Rhamnose was fermented mainly to 1,2-propanediol, succinate, and acetate, although the latter was quantitatively less than expected. Estimates of adenosine 5′-triphosphate (ATP) molar growth yields could not be calculated with any certainty, as ATP generation by electron transport-linked phosphorylation cannot yet be assessed. If ATP were generated by substrate-level phosphorylation reactions alone, ATP molar growth yields for xylose, arabinose, and rhamnose would be 30, 28, and 35 g/mol. If calculations are based on an assumption that two ATP are generated by electron transport-linked phosphorylation per succinate, ATP molar growth yields become 15, 14, and 22 g/mol; if the assumption is also made that the pathway of lactaldehyde reduction is coupled to production of one ATP per 1,2-propanediol by electron transport-linked phosphorylation, the ATP molar growth yield for rhamnose fermentation becomes 14 g/mol. No preference can be expressed between these alternatives at present.
Hyperproduction of tryptophan by Escherichia coli: genetic manipulation of the pathways leading to tryptophan formation
Authors: Tribe D E , Pittard J
Published: January 2020

Conversion of glucose and ammonium salts into tryptophan by mutants of Escherichia coli was examined as part of a feasibility study on the manufacture of tryptophan. This involved construction, largely by transduction, or a variety of multiple-mutation strains with defined genotypes. By comparing the properties of these strains, we were able to define in biochemical terms several changes that significantly enhance process productivity, namely (i) release of the first enzyme of the common pathway of aromatic biosynthesis and the first enzyme of the tryptophan pathway (3-deoxy-D-arabino-heptulosonate 7-phosphate synthase and the anthranilate aggregate, respectively) from inhibition by end products, (ii) blockage of the diversion of chorismate to phenylalanine and tyrosine biosynthesis, and (iii) presence of highly elevated tryptophan pathway enzyme levels, such as result from interference with both repression and attenuation, combined with gene amplification. By using strains carrying appropriate mutations to effect all of these changes, high values of specific productivity were obtained in bath culture (approximately 80 mg/g [dry weight] per h). Furthermore, a pronounced decay in the level of 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase activity was implicated as a cause of declining process producitivity during stationary phase, emphasizing the value of having derepressed levels of this enzyme.
Automated Enzymatic Method for the Determination of Ammonia: Application to Rumen Fluid, Gut Fluid, and Plasma
Authors: Baetz Albert L. , Faidley Terry D. , Allison Milton J.
Published: January 2020

The enzymatic method for the determination of ammonia with glutamate dehydrogenase has been adapted to the AutoAnalyzer. The automated method was applicable for NH
3
measurement in sheep rumen samples, swine gut fluid samples, and bovine plasma. Results were compared with those of the Conway diffusion method and the manual enzymatic method. The automated method allows 30 samples per h to be analyzed routinely. Values were comparable with those with the manual method, but lower than those with the Conway diffusion method.
Bile acid inhibition of Clostridium botulinum
Authors: Huhtanen C M
Published: January 2020

Bile acids and their glycine and taurine conjugates were tested in vitro for inhibition of Clostridium botulinum types A and B. Cholic acid inhibited most strains at 2 mg/ml, whereas chenodeoxycholic acid inhibited all strains at 0.4 mg/ml. Deoxycholic acid inhibited one strain at 0.08 mg/ml and other strains at 0.4 and 2 mg/ml. Lithocholic acid inhibited all strains at 0.016 mg/ml. Glycine conjugates also showed considerable inhibition of some strains, whereas taurine conjugates were inactive.
Rate-Temperature Curves as an Unambiguous Indicator of Biological Activity in Soil
Authors: Radmer Richard J. , Kok Bessel
Published: January 2020

Experiments are described in which we used a mass spectrometer to monitor O
2
uptake of enclosed soil samples as a function of temperature. We found that an Arrhenius plot of the rate of O
2
uptake showed pronounced local maxima attributable to biological activity, whereas similar plots of rates obtained with abiotic soils yielded straight lines. This procedure thus provides a basis for distinguishing biological from chemical activity for reactions, such as O
2
uptake, that can occur via either biological or chemical pathways.
Rapid seven-hour fecal coliform test
Authors: Reasoner D J , Blannon J C , Geldreich E E
Published: January 2020

A rapid 7-h fecal coliform (FC) test for the detection of FC in water has been developed. This membrane filter test utilizes a lightly buffered lactose-based medium (m-7-h FC medium) combined with a sensitive pH indicator system. FC colonies appeared yellow against a light purple background after incubation at 41.5 degrees C for 7 to 7.25 h. Comparison of FC test results showed that the mean verified FC count ratio (7-h FC count/24-h FC count) for surface water samples was 1.08. The mean FC count ratio (7-h FC count/24-h FC count) for unchlorinater wastewater ranged from 1.95 to 5.05. Verification of yellow FC colonies from m-7-h FC medium averaged 97%. Data from field tests on Lake Michigan bathing beach water samples showed that unverified 7-h FC counts averaged 96% of the 24-h FC counts. The 7-h FC test was found to be suitable for the examination of surface waters and unchlorinated sewage and could serve as an emergency test for detection of sewage or fecal contamination of potable water.
Effect of carbon dioxide on growth of Pseudomonas fluorescens
Authors: Gill C O , Tan K H
Published: January 2020

In minimal medium at 30 degrees C, growth of Pseudomonas fluorescens was stimulated when the pressure (p) of CO2 in solution was 100 mm of Hg, but at higher concentrations the growth rate declined linearly with increasing pCO2. All concentrations of CO2 were inhibitory for growth in complex medium, and at 30 degrees C the maximum degree of inhibition was attained when pCO2 was 250 mm of Hg. The degree of inhibition at a constant pCO2 in solution increased with decreasing temperature. The degree of inhibition was directly proportional to temperature for growth in complex medium, but not in minimal medium. The inhibition of cell respiration by CO2 was the same whether cells had been grown in air or in the presence of CO2, indicating that adaptive enzyme synthesis does not occur in response to CO2.
Microbial transformations of natural antitumor agents: conversion of lapachol to dehydro-alpha-lapachone by Curvularia lunata
Authors: Otten S , Rosazza J P
Published: January 2020

Microbial transformation of lapachol, a naturally occurring naphthoquinone, was carried out by Curvularia lunata (NRRL 2178). The fungus brings about oxidative cyclization of the substrate to dehydro-alpha-lapachone, which was isolated and characterized by nuclear magnetic resonance and mass spectral analyses; its structure was verified by chemical synthesis. The metabolite is a naturally occurring chromene possessing antibacterial and antitumor activities.
pH modification of the effects of detergents on the stability of enteric viruses
Authors: Ward R L , Ashley C S
Published: January 2020

The effect of detergents on the stability of enteric viruses was found to be highly dependent on pH. This was demonstrated primarily with two ionic detergents, sodium dodecyl sulfate (an anionic detergent) and dodecyltrimethylammonium chloride (a cationic detergent). Both detergents were shown to be potent virucidal agents for reovirus, but the effects of sodium dodecyl sulfate were minimal near neutrality and much more pronounced at low than at high pH values. Dodecyltrimethylammonium chloride was extremely virucidal at high pH's but had little observable effect on reovirus stability at low pH values. In contrast, both detergents protected enteroviruses against heat at neutral and alkaline pH's. However, as was found with reovirus, sodium dodecyl sulfate was extremely virucidal at pH values below 5, even when the virus samples were incubated in ice. At different pH's the effects of detergents on the stabilities of coliphages T4, f1, and Q beta were qualitatively similar to those found with reovirus. Differences in viral stability in these experiments appeared to be due to the effects of pH on the ionic states of the viral capsid proteins.
Stimulation of L-asparate beta-decarboxylase formation by L-glutamate in Pseudomonas dacunhae and Improved production of L-alanine
Authors: Shibatani T , Kakimoto T , Chibata I
Published: January 2020

The formation of L-asparate beta-decarboxylase by Pseudomonas dacunhae was compared on media containing a variety of organic acids and amino acids as a carbon source. Although the enzyme was formed constitutively when the organism was grown on basal medium or on that containing tricarboxylic acid cycle intermediates, it was induced twofold by L-glutamate and repressed one-tenth by L-serine. L-Glutamine, L-proline, L-leucine, glycine, and L-threonine also showed induction effects lower than that of L-glutamate. L-Glutamate derepressed the serine effect. This glutamate effect was observed effect was observed with other microoganisms, e.g., Achromobacter pestifer and Achromobacter liquidum. Since the intermediates from L-glutamate metabolism had no effect, this induction effect was specific to L-glutamate. The formation of some glutamate-related enzymes was measured and is discussed in relation to the formation of L-asparate beta-decarboxylase. L-Asparate beta-decarboxylase was purified to an electrophoretically homogenous state from L-glutamate-grown cells of P. dacunhae, and some properties were compared with those of the enzyme from fumarate-grown cells. The two enzymes were identical in disc electrophoresis, molecular weight, and some enzymatic properties. The industrial production of L-alanine from L-aspartic acid acid was improved by using the culture broth with highly induced L-asparate beta-decarboxylase (9.4 U/ml of broth).
Carboxymethyl Cellulose Decomposition by Intestinal Bacteria of Cockroaches
Authors: Cruden Diana Loeb , Markovetz A. J.
Published: January 2020

The amounts of carboxymethyl cellulase present in the midguts and hindguts of two species of cockroaches were determined. Numbers of colonies from the guts which digested carboxymethyl cellulose, visualized by flooding plates with cetyltrimethylammonium bromide after incubation, were counted. The numbers indicated the presence of a resident, multiplying population of predominantly anaerobic carboxymethyl cellulose-digesting bacteria in both species of cockroaches. Anaerobic and facultatively anaerobic species of bacteria were isolated, and their carboxymethylcellulase activities were assayed.
Catabolism of 5-chlorosalicylate by a Bacillus isolated from the Mississippi River
Authors: Crawford R L , Olson P E , Frick T D
Published: January 2020

A strain of Bacillus brevis isolated from a polluted section of the Mississippi River was shown to utilize 5-chloro-2-hydroxybenzoate (5-chlorosalicylate) as a sale source of carbon and energy. Enzymic analyses of cell-free extracts prepared from 5-chlorosalicylate-grown cells demonstrated that the initial step in the pathway involved cleavage of the aromatic ring between C1 and C2 by a specific 5-chlorosalicylate 1,2-dioxygenase. Loss of chloride from the growth substrate occurred after ring fission and was probably enzyme mediated. An intermediate chlorolactone apparently lost chloride by enzymatic hydrolysis with formation of maleylpyruvate. Maleylpyruvate was further degraded by both glutathione-dependent and glutathione-independent mechanisms, with these reactions being identical to the terminal reactions of the gentisate pathway. It was suggested that this novel 5-chlorosalicylate pathway may have evolved by recruitment of enzymes from an ancestral gentisate pathway.
Comparative Study of Different Iron Compounds in Inhibition of
Sphaerotilus
Growth
Authors: Chang Yueh , Pfeffer John T. , Chian Edward S. K.
Published: January 2020

The effectiveness of iron compounds on growth inhibition of
Sphaerotilus
species was compared. In this study, two strains of
Sphaerotilus
were tested with different iron concentrations in a synthetic sewage (S-medium) as formulated by Lackey and Wattie (Sewage Works J.
12
:669-684, 1940). For both strains, >80% inhibition of the maximum respiration rate was obtained by the following levels of soluble iron concentrations at pH 6.0: iron citrate, 20 mg/liter as Fe; iron cysteine, 5 mg/liter as Fe; and ferrous sulfate, 10 mg/liter as Fe. At a pH of 6.7 with iron citrate (20 mg/liter as Fe), inhibition of both strains was in excess of 50%. Insoluble iron compounds, such as iron hydroxides and ferrous carbonate, were found to be much less effective than the soluble iron compounds as inhibitors of these two strains. Aged iron hydroxide (500 mg/liter as Fe) produced a 70% inhibition in the maximum respiration rate while fresh iron hydroxide (52 mg/liter as Fe) and ferrous carbonate (500 mg/liter as Fe) produced a 20% inhibition. Chemical analyses of the iron-inhibited
Sphaerotilus
strains showed a close relationship between the inhibition of the organism's growth and the amount of iron sorbed by the organism.
Luminous Enteric Bacteria of Marine Fishes: a Study of Their Distribution, Densities, and Dispersion
Authors: Ruby E. G. , Morin J. G.
Published: January 2020

Three taxa of luminous bacteria (
Photobacterium fischeri, P. phosphoreum
, and
Beneckea
spp.) were found in the enteric microbial populations of 22 species of surface- and midwater-dwelling fishes. These bacteria often occurred in concentrations ranging between 10
5
and 10
7
colony-forming units per ml of enteric contents. By using a genetically marked strain, it was determined that luminous cells entering the fish during ingestion of seawater or contaminated particles traversed the alimentary tract and survived the digestive processes. After excretion, luminous bacteria proliferated extensively on the fecal material and became distributed into the surrounding seawater. Thus, this enteric habitat may serve as an enrichment of viable cells entering the planktonic luminous population.
Improved detection of coliforms and Escherichia coli in foods by a membrane filter method
Authors: Sharpe A N , Peterkin P I , Malik N
Published: January 2020

Analytical procedures based on filtration of homogenates through membrane filters, and particularly hydrophobic grid-membrane filters (HGMF), offer definite improvements in the enumeration of Escherichia coli and coliforms in foods. Whereas the counted specimen in pour plates may not usually be greater than 0.1 g, up to 1.0 g of ground beef, green beans, potato, cod, strawberries, or grapes could be filtered and counted on HGMF. Greatly improved limit of detection, reduced interference by noncoliforms, and complete removal of growth inhibitors such as polyphenols were demonstrated for HGMF, using violet red bile and mFC agars. In addition, counting on HGMF eliminated a false-positive reaction caused by sucrose in ice cream.
Zearalenone, deoxynivalenol, and T-2 toxin associated with stalk rot in corn
Authors: Mirocha C J , Schauerhamer B , Christensen C M , Kommedahl T
Published: January 2020

The mycotoxins zearalenone (2.8 micrograms/g), deoxynivalenol (1.5 microgram/g), and T-2 toxin (110 ng/g) have been found in the pith of corn stalks standing in the field. Such contaminated stalks may contribute to mycotoxicoses of farm animals.
Physiological Characteristics Underlying the Distribution Patterns of Luminous Bacteria in the Mediterranean Sea and the Gulf of Elat
Authors: Shilo M. , Yetinson T.
Published: January 2020

Physiological characteristics of luminous bacteria isolated from the Mediterranean and Gulf of Elat were compared to determine their relationship to the specific seasonal and geographic distribution patterns of these bacteria. The effects of temperature on growth rate and yield, relative sensitivity to photooxidation, resistance to high salt concentration (8%), and ability to grow in nutrient-poor conditions appear to control these patterns. The winter appearance of
Photobacterium fischeri
and the succession of winter and summer types of
Beneckea harveyi
in the eastern Mediterranean are explained by different temperature requirements for growth. Sensitivity to photooxidation explains the disappearance of
P. leiognathi
, present in the main body of the Gulf of Elat throughout the year, from the shallow coastal strip.
B. harveyi
is present in this coastal strip which is higher in nutrients and in productivity than the open waters. Competition experiments between
B. harveyi
and
P. leiognathi
in batch and continuous culture indicate that the oligotrophic
P. leiognathi
is outcompeted by
B. harveyi
in rich and even in relatively poor media. The distribution pattern found in the Bardawil hypersaline lagoon is explained by selection of salinity-resistant mutants of
B. harveyi
from the Mediterranean Sea.
Occurrence of Naegleria and Acanthamoeba in aquaria
Authors: De Jonckheere J F
Published: January 2020

Samples from 24 aquaria were incubated at 28, 37, and 45 degrees C for the isolation of Naegleria and Acanthamoeba. Naegleria was the predominant genus (60.9%), whereas Acanthamoeba represented 15.5% of the isolates. No pathogenic N. fowleri was identified, although a high number of strains were closely related to this species. One isolate (Aq/9/1/45D) was compared with an aquarium isolate (PPMFB-6) from Australia. The Belgian isolate was found to be more related to N. fowleri, whereas the Australian isolate was closer to N. gruberi.
Transformation of mercuric chloride and methylmercury by the rumen microflora
Authors: Kozak S , Forsberg C W
Published: January 2020

The microflora in strained rumen fluid did not methylate or volatilize 203Hg2+ at detectable rates. However, there was an exponential decay in the concentration of added CH3Hg+, which was attributed to demethylation. The major product of demethylation was metallic mercury (Hg0), and it was released as a volatile product from the reaction mixture. Demethylation occurred under both anaerobic and aerobic conditions. The rate of demethylation was proportional to the concentration of added CH3Hg+-Hg from 0.02 to 100 microgram of Hg per ml. The presence of HgCl2 had almost no inhibitory effect on the rate of cleavage of the carbon-mercury bond of CH2HgCl, but it completely inhibited volatilization of the Hg formed, when the concentration of HgCl2-Hg reached 100 micrograms/ml. Three of 11 species of anaerobic rumen bacteria catalyzed demethylation. These were Desulfovibrio desulfuricans, Selenomonas ruminantium, and Megasphaera elsdenii. None of the 11 species caused detectable methylation, and only two caused limited volatilization of Hg2+. Three species of bacteria out of 90 fresh aerobic isolates from rumen contents were demethylators: two were identified as Pseudomonas sp., and the third was a Micrococcus sp. Demethylation by the rumen microflora appeared to be carried out by both aerobic and anaerobic bacteria and, on the basis of Hg2+ sensitivity, probably resulted from the activity of two enzymes, a CH3-Hg+ hydrolase and a Hg2+ reductase.
Effect of environmental stress on Clostridium difficile toxin levels during continuous cultivation
Authors: Onderdonk A B , Lowe B R , Bartlett J G
Published: January 2020

A method for the continuous culture of Clostridium difficile has been described. It has been shown that subjecting continuous cultures of this microorganism to environmental stress results in increased levels of toxin in culture medium. Factors found to cause this release include alteration of the Eh from --360 to +100 mV or increasing the temperature from 37 to 45 degrees C. The increased toxin levels were not associated with a change in viable cell density or the numbers of spores present. Additional studies have shown that subinhibitory concentrations of vancomycin and penicillin, but not clindamycin, also cause an increase in toxin levels during continuous culture. The increase in supernatant toxin levels occurs concomitant with a decrease in sonicated cell extract toxin levels. The data suggest that a number of factors can cause a release of toxin from C. difficile into the surrounding medium.
Viral heat resistance and infectious ribonucleic acid
Authors: Larkin E P , Fassolitis A C
Published: January 2020

High-titer suspensions of poliovirus 1 and coxsackievirus B-2 were shown to contain a heat-resistant fraction when heated for 65 min at temperature ranging from 56 to 70 degrees C. The addition of ribonuclease to the heated suspensions eliminated plaque production in the cell cultures, indicating that the resistant fraction was infectious ribonucleic acid that had been liberated from ruptured viruses during the heating process.
Extracellular Polysaccharide of
Erwinia amylovora
: a Correlation with Virulence
Authors: Ayers Arthur R. , Ayers Sandra B. , Goodman Robert N.
Published: January 2020

The extracellular polysaccharides produced as slime or capsule layers by bacterial pathogens of animals and plants have been often implicated as factors essential to pathogenesis. In the present study, virulence of the plant pathogen
Erwinia amylovora
was correlated with the ability to produce extracellular polysaccharide (EPS). EPS production by a series of field isolates and bacterio-phage-resistant mutants differing in the extent to which they cause symptoms in host tissues was examined by quantitation with a modified Laurell rocket immunoelectrophoresis assay. The amount of EPS produced as an easily removed capsular layer or slime on solid nutrient agar approximated the capacity to exhibit symptoms in host inoculation tests. Features common to the virulent isolates are mucoid colony morphology, sensitivity to EPS-specific bacteriophages [Sφ3 and PEal(h)], and ability to produce a characteristic EPS. Mutants selected for resistance to Sφ3 or nonmucoid colony morphology are deficient in EPS production and have lost the ability to multiply in host tissue and cause symptoms. We conclude that EPS may be directly involved in symptom expression and provide a function essential to the growth of the pathogen in host tissues.
Temporal Change in Nitrous Oxide and Dinitrogen from Denitrification Following Onset of Anaerobiosis
Authors: Firestone Mary K. , Tiedje James M.
Published: January 2020

Similar temporal patterns were found in three mineral soils for the composition of the gaseous products of denitrification following the onset of anaerobic conditions. During the early period of anaerobiosis (0 up to 1 to 3 h), N
2
was the dominant product of denitrification. The NO
3
−
→ N
2
O activity then increased, but was not accompanied by a corresponding increase in N
2
O-reducing activity. This resulted in a relatively extended period of time (1 to 3 up to 16 to 33 h) during which N
2
O was a major product. Eventually (after 16 to 33 h), an increase in N
2
O-reducing activity occurred without a comparable increase in the N
2
O-producing activity. The increase in the rate of N
2
O reduction did not occur in the presence of chloramphenicol and required the presence of N
2
O or NO
3
−
during the preceding anaerobic incubation. During the final period (16 to 33, up to 48 h), N
2
was generally the sole product of denitrification, since the rate of N
2
O reduction exceeded the rate of N
2
O production. A similar sequential pattern was also found for a culture of a denitrifying
Flavobacterium
sp. shifted to anaerobic growth. A staggered synthesis of the enzymes in the denitrification sequence apparently occurred in response to anoxia, which caused first a net production of N
2
O followed by consumption of N
2
O.
Procedure for the recovery of airborne human enteric viruses during spray irrigation of treated wastewater
Authors: Moore B E , Sagik B P , Sorber C A
Published: January 2020

Because of the relatively low number of indigenous enteric viruses recovered from secondary wastewater effluents, their presence in air (aerosols) as a result of wastewater spray irrigation requires extensive sampling. Methodology to allow the recovery of indigenous enteroviruses from aerosols generated at an operational wastewater irrigation site was tested under both laboratory and field conditions.
Enzyme recruitment allows the biodegradation of recalcitrant branched hydrocarbons by Pseudomonas citronellolis
Authors: Fall R R , Brown J L , Schaeffer T L
Published: January 2020

Experiments were carried out to construct pseudomonad strains capable of the biodegradation of certain recalcitrant branched hydrocarbons via a combination of alkane and citronellol degradative pathways. To promote the metabolism of the recalcitrant hydrocarbon 2,6-dimethyl-2-octene we transferred the OCT plasmid to Pseudomonas citronellolis, a pseudomonad containing the citronellol pathway. This extended the n-alkane substrate range of the organism, but did not permit utilization of the branched hydrocarbon even in the presence of a gratuitous inducer of the OCT plasmid. In a separate approach n-decane-utilizing (Dec+) mutants of P. citronellolis were selected and found to be constitutive for the expression of medium- to long-chain alkane oxidation. The Dec+ mutants were capable of degradation of 2,6-dimethyl-2-octene via the citronellol pathway as shown by (i) conversion of the hydrocarbon to citronellol, determined by gas-liquid chromatography-mass spectrometry, (ii) induction of geranyl-coenzyme A carboxylase, a key enzyme of the citronellol pathway, and (iii) demonstration of beta-decarboxymethylation of the hydrocarbon by whole cells. The Dec+ mutants had also acquired the capacity to metabolize other recalcitrant branched hydrocarbons such as 3,6-dimethyloctane and 2,6-dimethyldecane. These studies demonstrate how enzyme recruitment can provide a pathway for the biodegradation of otherwise recalcitrant branched hydrocarbons.
Agar Slush as a Method to Insure Homogeneity of Monocentric Fungi in Continuous Culture
Authors: Amon James P. , Arthur Roger D.
Published: January 2020

Agar granules suspended in the growth medium reduce clumping, which permits the continuous culture of monocentric chytridiomycete fungi.
Autotrophic Growth of
Thiobacillus acidophilus
in the Presence of a Surface-Active Agent, Tween 80
Authors: Kingma J. G. , Silver Marvin
Published: January 2020

Cellular protein, pH, dissolved oxygen concentration, and static surface tension were measured during growth of
Thiobacillus acidophilus
on elemental sulfur in the absence and presence of up to 5,000 mg of Tween 80 per liter. The decrease in pH and the increase in sulfate production were observed to be less accurate measurements of growth when compared with the increase in cellular protein. The doubling time of the bacterium decreased approximately 50% with the addition of 500 mg of Tween 80 per liter. The bacteria did not appear to synthesize any wetting agents as demonstrated by the constant surface tension of the medium during growth. Morphological alterations in the presence of Tween 80 were also observed.
Biodegradation of 1,2,3- and 1,2,4-Trichlorobenzene in Soil and in Liquid Enrichment Culture
Authors: Marinucci A. C. , Bartha R.
Published: January 2020

The biodegradation of radiochemically pure (99%) 1,2,3- and 1,2,4-trichlorobenzene (TCB) in soil was investigated. Experimental difficulties posed by the high volatility and slow biodegradation rate of the TCBs were partially overcome by using a specially designed incubation and trapping apparatus. Evolution of
14
CO
2
from active versus poisoned soil dosed with 50 μg of the individual TCBs per g gave conclusive proof that both isomers are biodegradable. At 20°C, 1,2,4-TCB was mineralized at an approximate rate of 1 nmol/day per 20 g of soil sample, and 1,2,3-TCB was mineralized at one-half to one-third that rate. Mineral fertilizers or cosubstrates failed to increase TCB mineralization rates in soil. Anaerobic conditions had a negative effect on mineralization, and increased temperatures had a positive effect. With increasing 1,2,4-TCB concentrations,
14
CO
2
evolution exhibited saturation kinetics with an apparent

K
m

of 55.5 nmol per g of soil. Recovery of total radioactivity was good from soil containing high organic matter concentrations. From low-organic-matter soil, some of the radioactivity was recovered only on combustion, and overall recovery was lower. In soil-inoculated liquid culture, the cosubstrates glucose and benzene caused a slight stimulation of 1,2,4-TCB mineralization. Cochromatography of known standards with the extracts of soil pretreated with [
14
C]TCBs indicated that 3,4,5-trichlorophenol, 2,6-dichlorophenol and, to a lesser degree, 2,3-dichlorophenol were present in soils incubated with 1,2,3-TCB. 2,4-, 2,5-, and 3,4-dichlorophenol were present in soils incubated with 1,2,4-TCB.
N-demethylation of lergotrile by Streptomyces platensis
Authors: Davis P J , Glade J C , Clark A M , Smith R V
Published: January 2020

Thirty-eight microorganisms were screened for their ability to produce metabolites of the semisynthetic alkaloid, lergotrile. A total of five microorganisms were found to biotransform lergotrile, and N-desmethyl lergotrile was detected as the principal metabolite with most organisms. Streptomyces platensis (NRRL 2364) appeared to form the metabolite in highest yield, and a preparative-scale conversion was accomplished with a recovered yield of 50%. Structure proof was accomplished with comparative thin-layer chromatography, mixed melting point, mass spectrometry, and remethylation to lergotrile.
Sampling Culturable Heterotrophs from Microcosms: a Statistical Analysis
Authors: Kosinski Robert J. , Singleton Freddie L. , Foster Billy G.
Published: January 2020

The contributions of different sources of error in sampling mixed and unmixed bacterial microcosms were evaluated by using analysis of variance. Culturable heterotrophic bacteria from a turbid freshwater impoundment were sampled from 9-liter tanks that were unagitated or mixed with magnetic stirrers or pumps and from dilution bottles that were unagitated or agitated with a mechanical shaker. Axenic cultures of
Enterobacter aerogenes
were also sampled from manually shaken test tubes. In both agitated and unagitated tanks and in unagitated dilution bottles, dilutions made from the same sampling pipette were significantly different, showing a clumping of bacteria on the scale of millimeters. Also, microcosms within a single experiment differed from one another by a large margin. Dilution mean squares and tank or bottle mean squares were homogeneous for all types of tanks and unagitated bottles, indicating that the gentle mixing provided by pumps and stir bars did not reduce either millimeter scale or intermicrocosm variability over what prevailed in unagitated microcosms. By contrast, the vigorously shaken bottles and test tubes showed no millimeter scale variability. Intermicrocosm variability was undetectable in test tubes and two orders of magnitude less in shaken bottles than in unshaken bottles. When these facts are coupled with the inherent statistical advantage of replicating large rather than small experimental units, it is concluded that sampling error in the enumeration of aquatic bacteria in microcosms will be reduced by using numerous, small, violently agitated microcosms with a minimum of subsampling per microcosm.
Intestinal microbial flora of the of the American cockroach, Periplaneta americana L
Authors: Bracke J W , Cruden D L , Markovetz A J
Published: January 2020

A morphological study employing scanning and transmission electron microscopy was made by the alimentary tract of the American cockroach, Periplaneta americana L. A. complex microbiota of diverse morphology, which could not be readily dislodged, was observed and found to be restricted to the hindgut, particularly the colon. Numerous filamentous forms were noted, and some are described, including the morphologically distinct Methanospirillum. Flora was noted attached to the cuticular lining and cuticular filaments of the colon, and several spiral forms were observed in the luminal contents from the colon.
Plasmids in Escherichia coli controlling citrate-utilizing ability
Authors: Ishiguro N , Oka C , Hanzawa Y , Sato G
Published: January 2020

The citrate-utilizing ability of 19 out of 22 citrate-positive Escherichia coli strains isolated from pig sewage was transferred via conjugation to E. coli K-12. The conjugal transfer of citrate-utilizing (Cit) abilities was thermosensitive and concurrent with transfer of drug resistance. Weakly citrate-positive colonies were readily obtained in conjugation experiments. Their Cit characters could be transmitted to the other E. coli strains at a similar frequency in the retransfer experiments, and the transconjugants obtained still showed same characteristic growth on Simmons citrate agar plates. The 19 thermosensitive plasmids conferring citrate utilization and drug resistance were Fi-, and 16 of these plasmids belonged to incompatibility group H1. However, occasionally two conjugative plasmids (pOH3122-1 and pOH3124-1) carrying only the citrate utilization were also obtained in the conjugation experiments, and they were Fi+ and compatible with 19 reference R plasmids. In the two citrate-positive E. coli strains, it was suggested that the conjugative Cit plasmid showing Fi+ character and the more thermosensitive H1 plasmid conferring both the Cit character and drug resistance coexisted in the strain. The characterization of citrate utilization plasmids derived from pig farm sewage is discussed.
Influence of Substrate Composition on Marine Microfouling
Authors: Marszalek Donald S. , Gerchakov Sol M. , Udey Lanny R.
Published: January 2020

Glass and metal substrates exposed to subtropical seawater exhibit a characteristic succession of periphytic microorganisms. Substrates which are biologically and physically inert (glass and stainless steel) fouled rapidly and produced a complex, two-tier microfouling layer. Characteristic microorganisms were bacteria, fungi, choanoflagellates, diatoms, ciliates, and microalgae. Active substrates (brass and copper-nickel alloys) were selective for bacteria which secrete extracellular mucoid material, fouled at a slower rate, and were characterized by a less diverse microfouling community. Substrate appears to influence microfouling at all stages of development, especially in the early stages of substrate conditioning, and primary film formation. Primary films may insulate periphytic microorganisms from toxic substrates.
Structural and compositional changes associated with chlorine inactivation of polioviruses
Authors: O'Brien R T , Newman J
Published: January 2020

Chlorine inactivation of polioviruses resulted in the loss of viral ribonucleic acid, converting the viruses from 156S particles to 80S particles. However, it was found that virus inactivation occurred before the ribonucleic acid was released from the virions. Extraction of ribonucleic acid from partially inactivated virus suspensions indicated that chlorine inactivation was due to degradation of the ribonucleic acid before release and that ribonucleic acid loss was a secondary event. The empty 80S capsids had the same isoelectric point and ability to attach to host cells as infective virions. Thus, no major capsid conformational changes occurred during chlorine inactivation.
Transductional construction of a threonine-producing strain of Serratia marcescens
Authors: Komatsubara S , Kisumi M , Chibata I
Published: January 2020

A threonine-producing strain of Serratia marcescens Sr41 was constructed according to the following process. Thr- strain E-60 was derived from strain HNr59 having constitutive levels of threonine-sensitive aspartokinase and homoserine dehydrogenase. Thr+ transductant T-570 was constructed from strain E-60 and phage grown on strain HNr21 having feedback-resistant threonine-sensitive aspartokinase and homoserine dehydrogenase. This transductant lacked both feedback inhibition and repression for the two enzymes. Thr- strain N-11 was derived from strain AECr174 lacking feedback inhibition and repression of lysine-sensitive aspartokinase. Subsequently, the threonine region of strain T-570 was transduced into strain N-11. One of the THR+ transductants, strain T-693, produced markedly high levels of the two aspartokinases and homoserine dehydrogenase, which were insensitive to feedback inhibition. This strain produced about 25 mg of threonine per ml in the medium containing sucrose and urea.
Conversion of Glycerol to Dihydroxyacetone by Immobilized Whole Cells of
Acetobacter xylinum
Authors: Nabe Koichi , Izuo Nobuhiko , Yamada Shigeki , Chibata Ichiro
Published: January 2020

Enzymatic production of dihydroxyacetone (DHA) was studied by immobilization of the whole cells of acetic acid bacteria capable of oxidizing glycerol to DHA.
Acetobacter xylinum
A-9 cells immobilized in a polyacrylamide gel were selected as the most favorable enzyme preparation. The enzymatic properties of immobilized cells converting glycerol to DHA were investigated and compared with those of intact cells. The optimum pH for the immobilized cells was broad (4.0 to 5.5), whereas the intact cells had a narrow pH optimum at 5.5. The thermal stability of the immobilized cells was somewhat higher than that of the intact cells. Apparent
K

m

values for glycerol with both intact and immobilized cells were about equal, 6.3 × 10
−2
to 6.5 × 10
−2
M. The complete conversion of glycerol to DHA was achieved within 40 h under optimum conditions, and pure crystalline DHA was readily isolated from the reaction mixture with over 80% yield.
Neutron Activation Analysis for the Demonstration of Amphibolite Rock-Weathering Activity of a Yeast
Authors: Rades-Rohkohl E. , Hirsch P. , Fränzle O.
Published: January 2020

Neutron activation analysis was employed in a survey of weathering abilities of rock surface microorganisms. A yeast isolated from an amphibolite of a megalithic grave was found actively to concentrate, in media and in or on cells, iron and other elements when grown in the presence of ground rock. This was demonstrated by comparing a spectrum of neutron-activated amphibolite powder (particle size, 50 to 100 μm) with the spectra of neutron-activated, lyophilized yeast cells which had grown with or without amphibolite powder added to different media. The most active yeast (IFAM 1171) did not only solubilize Fe from the rock powder, but significant amounts of Co, Eu, Yb, Ca, Ba, Sc, Lu, Cr, Th, and U were also mobilized. The latter two elements occurred as natural radioactive isotopes in this amphibolite. When the yeast cells were grown with neutron-activated amphibolite, the cells contained the same elements. Furthermore, the growth medium contained Fe, Co, and Eu which had been solubilized from the amphibolite. This indicates the presence, in this yeast strain, of active rockweathering abilities as well as of uptake mechanisms for solubilized rock components.
Determination of endotoxins in sugar with the Limulus test
Authors: Haskå G , Nystrand R
Published: January 2020

The Limulus amebocyte lysate test has been used for determination of pyrogens in sugar of different qualities. All the samples of domestic white sugar and beet raw sugar produced in Sweden during 1976 had a very low content of endotoxins, less than 10 ng/g of sugar. Imported cane raw sugar was, however, highly contaminated. The highest value obtained corresponds to about 100 mg of Escherichia coli endotoxin per g of raw sugar. Such crude sugar cannot, even after refining, be used for medical purposes. Instead, Swedish beet sugar is used as the raw material for production of invert sugar solutions for parenteral administration. The amount of endotoxin in this sugar is less than 1 ng/g.
Purification, Immobilization, and Some Properties of Glucose Isomerase from
Streptomyces flavogriseus
Authors: Chen W. P. , Anderson A. W.
Published: January 2020

Glucose isomerase (EC 5.3.1.5) produced from
Streptomyces flavogriseus
was purified by fractionation with (NH
4
)
2
SO
4
and chromatography on diethylaminoethyl (DEAE)-cellulose and DEAE-Sephadex A-50 columns. The purified enzyme was homogeneous as shown by ultracentrifugation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Benzyl DEAE-cellulose, triethylaminoethyl-cellulose, and DEAE-cellulose were effective in the immobilization of partially purified glucose isomerase. Several differences in properties were found between purified soluble enzyme, immobilized enzyme (DEAE-cellulose-glucose isomerase), and heat-treated whole cells. Glucose and xylose served as substrate for the enzyme. Whole cells had the highest

K
m

values for glucose and xylose; the soluble enzyme had the lowest values. The optimum temperature for activity of the soluble and immobilized enzymes was 70°C; that for whole cells was 75°C. The pH optimum for the three enzyme preparations was 7.5. Magnesium ion or Co
2+
was required for enzyme activity; an addition effect resulted from the presence of both Mg
2+
and Co
2+
. The enzyme activity was inhibited by Hg
2+
, Ag
+
, or Cu
2+
. The conversion ratio of the enzyme for isomerization was about 50%. The soluble and immobilized enzymes showed a greater heat stability than whole cells. The soluble enzyme was stable over a slightly wider pH (5.0 to 9.0) range than the immobilized enzyme and whole cells (pH 5.5 to 9.0). The molecular weight of the enzyme determined by the sedimentation equilibrium method was 171,000. A tetrameric structure for the enzyme was also indicated. After operating at 70°C for 5 days, the remaining enzyme activity of the immobilized enzyme and whole cells, which were used for the continuous isomerization of glucose in a plug-flow type of column in the presence of Mg
2+
and Co
2+
, was 75 and 55%, respectively. Elimination of Co
2+
decreased operational stability.
In vitro production of Rauscher murine leukemia virus: influence of culture age on biological properties
Authors: Robinson O R , Perry A , Shibley G P , de Maio M
Published: January 2020

Large-scale production and concentration procedures have been standardized to study the biological properties of Rauscher leukemia virus produced from the high-passaged JLS-V9-H mouse bone marrow cell line. Virus produced early (days 4 to 6) in the harvest and refeed cycle contained higher levels of ribonucleic acid-directed deoxyribonucleic acid polymerase activity and was more infectious than Rauscher leukemia virus produced later (days 7 to 10) in the growth period. The peak of virus production as detected by physical assays (virus particle count, protein, and p30 antigen) was highest at day 6, whereas the optimum biological and ribonucleic acid-directed deoxyribonucleic acid polymerase activity occurred 24 h earlier. When product characterization values of each concentrate were adjusted to a specific activity (i.e., per milligram of protein) basis, virus particle counts averaged 4 x 10(11) through days 5 to 9, and the peak infectivity occurred at day 4, whereas ribonucleic acid-directed deoxyribonucleic acid polymerase activity was highest at day 4 (endogenous) and 5 (exogenous). Sodium dodecyl sulfate-polyacrylamide gel analysis revealed only slight differences in the polypeptide pattern of Rauscher leukemia virus harvested from cultures of varying age, although Rauscher leukemia virus produced between days 3 and 5 contained more glycoprotein than either earlier or later harvests.