bluuebunny/crossref_metadata_2025 huggingface dataset:
Nodulation Efficiency of Legume Inoculation as Determined by Intrinsic Antibiotic Resistance
Authors: Kremer Robert J. , Peterson Harold L.
Published: January 2020

Patterns of intrinsic resistance and susceptibility to different levels of antibiotics were determined for strains of both fast- and slow-growing rhizobia. These patterns were stable to plant passage when they were used to identify
Rhizobium
strains in nodule suspensions or nodule isolates. The method of identification by intrinsic resistance and susceptibility patterns was reliable for identifying strains in field nodules when strains were first isolated from the nodules to provide a standard inoculum size and then typed on antibiotic-containing media. Other patterns of resistance were encountered during identification of field isolates; these patterns may have resulted from acquired resistance to certain antibiotics or from mixed infections of the nodules. The occurrence of resistance patterns identical to those of inoculant strains among native strains was directly related to the size of the soil population. High strain recovery was associated directly with high rates of inoculation.
Production of Extracellular Pigment by a Mutant of
Monascus kaoliang
sp. nov
Authors: Lin Ching-Fwu , Iizuka Hiroshi
Published: January 2020

A hyperpigment-producing mutant, R-10847, was derived from
Monascus kaoliang
F-2 (ATCC 26264) through a series of mutagenesis steps. The mutant produced a large quantity of
Monascus
pigment when grown in mantou (steamed bread) by solid culture. The mutant produced pigments extracellularly by extruding the pigments outside the cell in a lump together with some viscous substances. The productivity of pigment was about 100-fold greater than that of the wild type. The mutant lost the capability of spore formation, the growth rate decreased, and both the size and quantity of conidia were reduced. The color of the pigment produced by the mutant changed from orange to deep red.
Recognition of Leguminous Hosts by a Promiscuous
Rhizobium
Strain
Authors: Shantharam S. , Wong Peter P.
Published: January 2020

The lima bean (
Phaseolus lunatus
L.) and the pole bean (
Phaseolus vulgaris
L.) are nodulated by rhizobia of two different cross-inoculation groups.
Rhizobium
sp. 127E15, a cowpea-type
Rhizobium
, can induce effective nodules on the lima bean and partially effective nodules on the pole bean.
Rhizobium phaseoli
127K14 can induce effective nodules on the pole bean but does not reciprocally nodulate the lima bean. Root hairs of the lima bean when inoculated with
Rhizobium
sp. 127E15 showed tip curling and swelling and infection thread formation as observed by light microscopy and scanning electron microscopy. When lima bean root hairs were inoculated with
R. phaseoli
127K14, no host-specific responses were observed. Pole bean root hairs that had been inoculated with
R. phaseoli
127K14 or
Rhizobium
sp. 127E15 also showed tip curling and swelling and infection thread formation. Colonization of lima bean root hairs by
Rhizobium
sp. 127E15 and pole bean root hairs by
R. phaseoli
127K14 or
Rhizobium
sp. 127E15 appeared to involve the elaboration of microfibrils. This study showed that when
Rhizobium
sp. 127E15 nodulates a host of a different cross-inoculation group, it elicits the same specific host responses as it does from a host of the same cross-inoculation group.
Resistance of Mycobacterium chelonei-like organisms to formaldehyde
Authors: Hayes P S , McGiboney D L , Band J D , Feeley J C
Published: January 2020

Mycobacterium chelonei-like organisms have been isolated from patients in two outbreaks of peritonitis involving chronic peritoneal dialysis machines routinely disinfected with 2 to 3% formaldehyde. Susceptibility studies revealed that water-adapted M. chelonei-like organism strains could survive 2 h of exposure to 10% formaldehyde.
Isolation of Pittsburgh pneumonia agent from a hospital shower
Authors: Brown A , Yu V L , Magnussen M H , Vickers R M , Garrity G M , Elder E M
Published: January 2020

Tatlockia (Legionella) micdadei, the Pittsburgh pneumonia agent, was isolated from a hospital shower. Although it was not possible, at the current time, to establish an epidemiological link to disease acquisition, this information may be significant because it provides further evidence that a water-associated reservoir of this organism exists within the hospital.
Influence of Acetylene on Growth of Sulfate-Respiring Bacteria
Authors: Payne W. J. , Grant M. A.
Published: January 2020

At a concentration of 20% of the atmosphere of the culture flasks, acetylene inhibited growth and carbon dioxide production by
Desulfovibrio desulfuricans
and
Desulfovibrio gigas.
The bacteria did not reduce acetylene to ethylene, and neither acetylene dicarboxylic acid nor ethylene was inhibitory. At 10%, acetylene was partially inhibitory for the desulfovibrios. At 5%, acetylene impeded the rate but did not limit the extent of growth and catabolism of the desulfovibrios.
Desulfotomaculum ruminis
was affected only negligibly, if at all, by acetylene and ethylene at any of these concentrations.
Reduction of Cytotoxicity in Virus Concentrates from Environmental Samples
Authors: Hejkal Thomas W. , Gerba Charles P. , Rao V. C.
Published: January 2020

The reduction of cytotoxicity in virus concentrates from environmental samples was accomplished by high-speed centrifugation and by filtration of the samples through positively charged depth filters.
Free Ammonia Inhibition of Algal Photosynthesis in Intensive Cultures
Authors: Azov Y. , Goldman Joel C.
Published: January 2020

The effect of free NH
3
inhibition on short-term photosynthesis was investigated in three microalgal species: the freshwater chlorophyte
Scenedesmus obliquus
, the marine diatom
Phaeodactylum tricornutum
and the marine chlorophyte
Dunaliella tertiolecta.
By performing a series of assays at various concentrations of added NH
4
Cl and culture pH, we demonstrated that the inhibitory compound was free NH
3
and that pH played no role in determining the magnitude of inhibition, other than in establishing the degree of dissociation of nontoxic NH
4
+
to toxic NH
3
. When corrections were made for pH, all three species displayed the same sigmoidal response curve to free NH
3
concentration; 1.2 mM NH
3
led to 50% reduction in photoassimilation of
14
C. Based on literature values, some marine phytoplankton appear to be significantly more sensitive to free NH
3
than were the test species, which are noted for their excellent growth characteristics. However, the combination of low algal biomass and strong pH buffering commonly found in most marine and many freshwater environments probably limits the possibilities for NH
3
toxicity to low alkalinity freshwaters and intensive algal cultures in which NH
4
+
is the main source of N. Such conditions occur commonly in algal wastewater treatment systems.
Use of Congo red-polysaccharide interactions in enumeration and characterization of cellulolytic bacteria from the bovine rumen
Authors: Teather R M , Wood P J
Published: January 2020

The interaction of the direct dye Congo red with intact beta-D-glucans provides the basis for a rapid and sensitive assay system for bacterial strains possessing beta-(1 leads to 4),(1 leads to 3)-D-glucanohydrolase, beta-(1 leads to 4)-D-glucanohydrolase, and beta-(1 leads to 3)-D-glucanohydrolase activities. A close correspondence was observed between cellulolytic activity and beta-(1 leads to 4)-D-glucanohydrolase and beta-(1 leads to 4),(1 leads to 3)-D-glucanohydrolase activities in isolates from the bovine rumen. Many of these isolates also possessed beta-(1 leads to 3)-D-glucanohydrolase activity, and this characteristic may have taxonomic significance.
Ametryne and Prometryne as Sulfur Sources for Bacteria
Authors: Cook Alasdair M. , Hütter Ralf
Published: January 2020

Bacteria were isolated that could utilize quantitatively the s-triazine herbicide prometryne [
N,N
′ -bis(1-methylethyl)-6-(methylthio)-1,3,5-triazine-2,4-diamine] or ametryne [
N
-ethyl-
N
′-(1-methylethyl)-6-(methylthio)-1,3,5-triazine- 2,4-diamine], or both, as a sole source of sulfur for growth. The success of enrichments depended on previous exposure of the soil inoculum to s-triazine herbicides. Deaminoethylametryne [4-(1-methylethyl)amino-6-(methylthio)-1,3,5-triazine-2-(1H)-one], methylsulfonic acid, and sodium sulfate could also be used as sulfur sources. Utilization of a compound was quantified as the growth yield per mole of sulfur supplied. Yields were about 6 kg of protein per mol of sulfur. The product of the desulfuration of an s-triazine was identified as the corresponding hydroxy-derivative. This is the first substantiated report of the utilization of these s-triazines as sulfur sources by bacteria.
Nitrogen Fixation (Acetylene Reduction) Associated with Duckweed (
Lemnaceae
) Mats
Authors: Zuberer D. A.
Published: January 2020

Duckweed (
Lemnaceae
) mats in Texas and Florida were investigated, using the acetylene reduction assay, to determine whether nitrogen fixation occurred in these floating aquatic macrophyte communities. N
2
-fixing microorganisms were enumerated by plating or most-probable-number techniques, using appropriate N-free media. Results of the investigations indicated that substantial N
2
-fixation (C
2
H
2
) was associated with duckweed mats in Texas and Florida. Acetylene reduction values ranged from 1 to 18 μmol of C
2
H
4
g (dry weight)
−1
day
−1
for samples incubated aerobically in light. Dark N
2
fixation was always two- to fivefold lower. 3-(3,4-Dichlorophenyl)-1,1-dimethylurea (7 to 10 μM) reduced acetylene reduction to levels intermediate between light and dark incubation. Acetylene reduction was generally greatest for samples incubated anaerobically in the light. It was estimated that 15 to 20% of the N requirement of the duckweed could be supplied through biological nitrogen fixation. N
2
-fixing heterotrophic bacteria (10
5
cells g [wet weight]
−1
and cyanobacteria (10
5
propagules g [wet weight]
−1
were associated with the duckweed mats.
Azotobacter
sp. was not detected in these investigations. One diazotrophic isolate was classified as
Klebsiella.
Inhibition of Clostridium botulinum by antioxidants, phenols, and related compounds
Authors: Reddy N R , Pierson M D , Lechowich R V
Published: January 2020

A total of 75 compounds, including antioxidants, preservatives, gallic acid and p-hydroxybenzoic acid esters, hydroquinones, hydroxyquinolines, phenol derivatives, and related compounds, were screened for their antibotulinal activity in prereduced Thiotone-yeast extract-glucose broth. The most effective inhibitors of Clostridium botulinum growth and toxin production were long-chain esters of p-hydroxybenzoic acid and gallic acid, antioxidants, and butylphenol derivatives. The antioxidant nordihydroguaiaretic acid at 100 microgram/ml delayed the growth and toxin production for the entire incubation period (7 days). Other antioxidants, such as butylated hydroxytoluene, butylated hydroxyanisole, and tert-butylhydroquinone were also very effective (at 200 to 400 microgram/ml) for the inhibition of C. botulinum growth and toxin production. Toxin was detected, although no detectable growth was found by daily absorbance measurements, in the prereduced medium containing 50 to 400 microgram of 8-hydroxyquinoline, pentylphenol, tert-pentylphenol, 3,5-ditert-butylphenol, 3,5-ditert-butylcatechol, (2-hydroxydiphenyl)methane, or (4-hydroxydiphenyl)methane per ml.
Enhancement by Sodium Dodecyl Sulfate of Pigment Formation in
Serratia marcescens
O8
Authors: Feng J. S. , Webb J. W. , Tsang J. C.
Published: January 2020

Three methods were used to determine the enhancement by sodium dodecyl sulfate (SDS) of prodigiosin formation in
Serratia marcescens
O8. The results of the agar disk diffusion method indicated that pigment formation was dependent upon the concentration of SDS. Diameters of the pigment zones were proportional to the logarithm of SDS concentrations of 300 to 1,500 μg/ml. When bacteria were grown in broth containing SDS from 0 to 800 μg/ml and the pigment extracts were analyzed spectrophotometrically, a similar enhancement of pigment formation was observed. Finally, these results were confirmed by high-performance liquid chromatographic analysis of the extracts. Prodigiosin appeared to be the sole component with increased synthesis. The possible mechanism of the SDS enhancement effect could be explained by an increase in negative binding sites by the association of SDS with a cell envelope component(s). These binding sites may be required for prodigiosin synthesis.
Microbial transformations of warfarin: stereoselective reduction by Nocardia corallina and Arthrobacter species
Authors: Davis P J , Rizzo J D
Published: January 2020

The microbiological metabolism of warfarin was examined as a model of metabolism in higher organisms, including humans, and to determine the chirality of microbial reductases for application in organic synthesis. Nineteen cultures were examined based on their reported abilities to reduce ketonic substrates, and several were shown to catalyze the desired reaction. Nocardia corallina (ATCC 19070) exhibited complete substrate and product stereoselectivity as it reduced S-warfarin to the corresponding S-alcohol. Arthrobacter species (ATCC 19140) exhibited marked substrate and complete product stereoselectivity since S-warfarin, and to a lesser extent R-warfarin, were reduced to the corresponding S-alcohols. These reductions parallel those reported to occur in mammalian species.
Increased production of aflatoxins by Aspergillus parasiticus Speare in the presence of rubratoxin B
Authors: Moss M O , Badii F
Published: January 2020

The influence of rubratoxin B, a metabolite of Penicillium rubrum Stoll, on the growth and aflatoxin production of a strain of Aspergillus parasiticus Speare grown in the chemically defined medium of Reddy et al. (Appl. Microbiol. 22:393-396, 1971) was studied. After 4 days of incubation on a rotary shaker at 25 degrees C, the presence of 10 microgram/ml caused 45 to 50% reduction in dry weight production, although at the same concentration of rubratoxin B, the reduction of growth after 10 days was only 15%. In the presence of 50 microgram/ml there was a reduction in dry weight production of 94% after 4 days of incubation, and it was still 86% after 8 days. Rubratoxin B concentrations of 50 microgram/ml and higher usually caused a reduction in aflatoxin production in the medium comparable with the reduction in biomass, but at concentrations as low as 10 microgram/ml, there was a pronounced increase in the production of aflatoxins, especially of G1, despite the reduction in biomass. The ecological significance of these observations is discussed.
Scanning electron microscope study of Pseudomonas fragi on intact and sarcoplasm-depleted bovine longissimus dorsi muscle
Authors: Yada R Y , Skura B J
Published: January 2020

Intact bovine longissimus dorsi muscle strips used 24 h postmortem were washed to remove sarcoplasmic fluid or left intact and were either left uninoculated or inoculated with Pseudomonas fragi ATCC 4973. The effects of decreased sarcoplasm concentration on growth of P. fragi and consequent microstructural changes of beef muscle during aerobic storage at 4 degrees C for 12 days were evaluated. P. fragi grew slower on washed muscle than on intact muscle. Scanning electron micrographs revealed surface degradation of both intact inoculated and washed inoculated muscle only in areas of localized colonization. Extracellular fibrils appeared to mediate adhesion of P fragi to the muscle surface as well as cell-to-cell attachment within microcolonies. P. fragi was also observed growing between muscle fibers.
Use of Nitrifier Activity Measurements To Estimate the Efficiency of Viable Nitrifier Counts in Soils and Sediments
Authors: Belser L. W. , Mays E. L.
Published: January 2020

A procedure for estimating the efficiency of the most-probable number (MPN) technique for counting ammonium-oxidizing bacteria was tested on sediments and soils collected from Delaware Inlet, Nelson, New Zealand. The procedure involved estimating the nitrifier populations required to produce observed activities and comparing these estimates with the MPN-countable populations. MPN counts ranged between 0.15 × 10
3
to 3.0 × 10
3
cells g
−1
in sediments and between 4.4 × 10
3
to 19 × 10
3
cells g
−1
in soils. These counts were only 0.1 to 5.0% of the estimated populations that would be required to produce the observed activity. Similar efficiency calculations were made for data already in the literature, and these calculations gave much higher percentages. Thus, we concluded that for the soils and sediments we studied, the MPN counting technique greatly underestimated the populations present and that the efficiency calculation could be used as a counting efficiency index.
Effects of polychlorinated biphenyls and environmental biotransformation products on aquatic nitrification
Authors: Sayler G S , Shiaris M P , Beck W , Held S
Published: January 2020

The effects of polychlorinated biphenyls (PCBs) on nitrification were examined for pure cultures and natural reservoir samples. PCBs at concentrations greater than 10 microgram liter-1 inhibited nitrification, principally ammonium oxidation, in one of two natural reservoir environments. However, this inhibition could not be reproduced in pure high-cell-density cultures or in previously contaminated reservoir waters. A PCB environmental biotransformation product, p-chlorophenylglyoxylic acid, and p-chloromandelic acid had no effect on nitrification.
Production of vomitoxin on corn by Fusarium graminearum NRRL 5883 and Fusarium roseum NRRL 6101
Authors: Vesonder R F , Ellis J J , Kwolek W F , DeMarini D J
Published: January 2020

Two vomitoxin-producing isolates of Fusarium spp. were grown on cracked corn for 1 to 8 weeks at 15, 20, 25, 28, and 32 degrees C. Maximum production of vomitoxin by Fusarium graminearum Schw. NRRL 5883 occurred at 30 degrees C and 40 days, and that by Fusarium roseum Schw. NRRL 6101 occurred at 26 degrees C and 41 days. These optimum production points were determined from response surface contour graphs in relation to temperature and time. Only small amounts of vomitoxin were produced at 15 and 20 degrees C by each strain. A 133-microgram quantity of vomitoxin, with an indicated purity of 95%, was isolated per gram of corn fermented with F. graminearum NRRL 5883.
Water-to-Air Transfer and Enrichment of Bacteria in Drops from Bursting Bubbles
Authors: Blanchard Duncan C. , Syzdek Lawrence D.
Published: January 2020

An electrostatic induction technique was used to determine both drop size distribution and concentration of bacteria in the film drops produced by bubbles bursting at the surface of a suspension of
Serratia marcescens
. Film drops are produced from the collapse of the thin film of water that just before bursting separates the air in the bubble from the atmosphere. Bubbles of 1.7-mm diameter produced from 10 to 20 film drops which ranged from <2 μm to over 30 μm in diameter. Half the drops were <10 μm. For bubbles rising a distance of less than 2 cm through the bacterial suspension, bacterial enrichment factors in the drops were between 10 and 20. Electrostatic methods can be used to determine the enrichment of bacteria in film drops as a function of bubble size and distance of rise through the bacterial suspension.
Antimicrobial characteristic of insoluble alkylpyridinium iodide
Authors: Nakagawa Y , Yamano Y , Tawaratani T , Kourai H , Horie T , Shibasaki I
Published: January 2020

Insoluble and soluble alkylpyridinium iodides (C8 to C18) were synthesized. The insoluble agents were quaternized 4-vinylpyridine-divinylbenzene copolymers. The insoluble agent [C12(50)] that contained 50% divinylbenzene and had a C12 alkyl chain was selected as the most suitable insoluble agent. C12(50) showed poor durability of the antibacterial activity, but C12(50), which had lost the activity, was refreshed by washing with ethanol. This washing became ineffective after a few cycles of antibacterial treatment and refreshment. Such C12(50) recovered the activity upon 1.0 N NaOH treatment. The antibacterial activity of C12(50) depended on its surface area. It showed high antimicrobial activity against gram-positive bacteria and also showed activity against gram-negative bacteria and yeasts. But the activities of C12(50) and laurylpyridinium iodide solution were different against some microbes. The antibacterial activities of the agents were investigated against Escherichia coli and Micrococcus luteus under various conditions. The activity of C12(50) was higher at a higher temperature or at a lower cell concentration. The activity of C12(50) decreased on addition of NaCl, glucose, or bovine albumin to the cell suspension or in 0.01 M sodium-potassium phosphate buffer. C12(50) showed less activity when cells were mixed with dead cells or the supernatant of dead cells killed in an autoclave. The mode of action of the laurylpyridinium iodide solution against E. coli and M. luteus was similar to that of C12(50) except for the influence of E. coli cell concentration.
Characterization of NADP-dependent 7 beta-hydroxysteroid dehydrogenases from Peptostreptococcus productus and Eubacterium aerofaciens
Authors: Hirano S , Masuda N
Published: January 2020

Peptostreptococcus productus strain b-52 (a human fecal isolate) and Eubacterium aerofaciens ATCC 25986 were found to contain NADP-dependent 7 beta-hydroxysteriod dehydrogenase activity. The enzyme was synthesized constitutively by both organisms, and the enzyme yields were suppressed by the addition of 0.5 mM 7 beta-hydroxy bile acid to the growth medium. Purification of the enzyme by chromatography resulted in preparations with 3.5 (P. productus b-52, on Sephadex G-200) and 1.8 (E. aerofaciens, on Bio-Gel A-1.5 M) times the activity of the crude cell extracts. A pH optimum of 9.8 and a molecular weight of approximately 53,000 were shown for the enzyme of strain b-52, and an optimum pH at 10.5 and a molecular weight of 45,000 was shown for that from strain ATCC 25986. Kinetic studies revealed that both enzyme preparations oxidized the 7 beta-hydroxy group in unconjugated and conjugated bile acids, a lower Km value being demonstrated with free bile acid than with glycine and taurine conjugates. No measureable activity against 3 alpha-, 7 alpha-, or 12 alpha-hydroxy groups was detected in either enzyme preparation. When tested with strain ATCC 25986, little 7 beta-hydroxy-steroid dehydrogenase activity was detected in cells grown in the presence of glucose in excess. The enzyme from strain b-52 was found to be heat labile (90% inactivation at 50 degrees C for 3 min) and highly sensitive to sulfhydryl inhibitors.
Uptake of bacteriophage f2 through plant roots
Authors: Ward R L , Mahler R J
Published: January 2020

A model system was designed to measure viral uptake through the roots of plants and translocation to distal plant parts. For this study, uptake of bacteriophage f2 was measured in corn and bean plants growing in hydroponic solutions. Few phage were detected in plants with uncut roots. However, when roots of both plant types were cut just before exposure to very high concentrations of phage, the amount of phage uptake was several orders of magnitude greater than with uncut roots, but still was considerably less than that which was theoretically possible. Furthermore, cut roots were rapidly repaired, thus inhibiting uptake, and the amount of uptake in plants with cut roots was proportional to phage exposure levels. Finally, phage were transported to all plant parts examined, but their survival times within each portion of the plants appeared to be of limited duration. All of these factors tend to minimize the possible public health significance associated with viral uptake through the root systems of plants.
Transformation of
Streptococcus lactis
Protoplasts by Plasmid DNA
Authors: Kondo Jeffery K. , McKay Larry L.
Published: January 2020

Polyethylene glycol-treated protoplasts prepared from
Streptococcus lactis
LM3302, a lactose-negative (Lac
−
) derivative of
S. lactis
ML3, were transformed to lactose-fermenting ability by a transductionally shortened plasmid (pLM2103) coding for lactose utilization.
Evidence that microorganisms cause inactivation of viruses in activated sludge
Authors: Ward R L
Published: January 2020

Virus loss in activated sludge appeared to be caused by microorganisms. This conclusion is supported by the finding that poliovirus infectivity decreased during incubation in mixed-liquor suspended solids, primarily because of a sedimentable, heat-sensitive component. Furthermore, broth spiked with mixed-liquor suspended solids acquired antiviral activity during incubation.
Nitrogenase Activity Associated with
Halodule wrightii
Roots
Authors: Smith Garriet W. , Hayasaka Steven S.
Published: January 2020

Nitrogen fixation (acetylene reduction) associated with roots of the seagrass
Halodule wrightii
was measured offshore near Beaufort and Moorhead City, N.C. Rates of acetylene reduction were higher in aerobic than in anaerobic assays and were linear for up to 5 days. The temperature range for acetylene reduction was 15 to 35�C with a maximum activity at 35�C. Nitrogenase activity was shown to vary seasonally with highest activities occurring during warmer summer months (23 μg of N
2
fixed per m
2
per day). At in situ temperature, nitrogenase activities associated with surface-sterilized and non-surface-sterilized roots were similar. One morphological bacterial type was isolated from surface-sterilized roots and identified as
Klebsiella pneumoniae
type 4B.
Fluorescein Diacetate Hydrolysis as a Measure of Total Microbial Activity in Soil and Litter
Authors: Schn�rer Johan , Rosswall Thomas
Published: January 2020

Spectrophotometric determination of the hydrolysis of fluorescein diacetate (FDA) was shown to be a simple, sensitive, and rapid method for determining microbial activity in soil and litter. FDA hydrolysis was studied in soil and straw incubated for up to 3 h. Hydrolysis was found to increase linearly with soil addition. FDA hydrolysis by pure cultures of
Fusarium culmorum
increased linearly with mycelium addition both in shake cultures and after inoculation into sterile soil. FDA hydrolysis by
Pseudomonas denitrificans
increased linearly with biomass addition. The FDA hydrolytic activities in soil samples from different layers of an agricultural soil were correlated with respiration. Acetone was found to be suitable for terminating the reaction.
Microbial spoilage of whole sheep livers
Authors: Gill C O , DeLacy K M
Published: January 2020

When liver treated with antibiotics to inhibit microbial growth were held at 10 degrees C, the initial high pH (6.4) declined as lactic acid accumulated throughout the storage period of 10 days. The glycogen content also declined, but the glucose concentration in the tissues remained high. When livers were allowed to spoil at 10 degrees C, distinct but variable floras developed within the tissues, in the drip, and on the upper surface. Deep-tissue floras were composed of anaerobic and facultative organisms (Lactobacillus, Enterobacter, Aeromonas); surface floras were generally dominated by strictly aerobic organisms (Pseudomonas, Acinetobacter); drip floras contained variable proportions of organisms of all three types, but the facultatively anaerobic Enterobacter were usually present as a major component. Spoilage occurred after 4 to 6 days with the development of visible discrete colonies on the upper surface without spoilage odors being evident. Changes in tissue and drip composition due to microbial activity could be detected only when spoilage had reached an advanced stage.
Multiplication of Legionella pneumophila in unsterilized tap water
Authors: Yee R B , Wadowsky R M
Published: January 2020

Naturally occurring Legionella pneumophila, an environmental isolate which had not been grown on artificial medium, was tested for the ability to multiply in tap water. A showerhead containing L. pneumophila and non-Legionellaceae bacteria was immersed in nonsterile tap water supplying this fixture. Also L. pneumophila and non-Legionellaceae bacteria were sedimented from tap water from a surgical intensive care unit. This bacterial suspension was inoculated into tap water from our laboratory. The legionellae in both suspensions multiplied in the tap water at 32, 37, and 42 degrees C. The non-Legionellaceae bacteria multiplied at 25, 32, and 37 degrees C. A water sample which was collected from the bottom of a hot water tank was found to contain L. pneumophila and non-Legionellaceae bacteria. These legionellae also multiplied when the water sample was incubated at 37 degrees C. These results indicate that L. pneumophila may multiply in warm water environments such as hot water plumbing fixtures, hot water tanks, and cooling towers.
Fluorometric Determination of DNA in Aquatic Microorganisms by Use of Hoechst 33258
Authors: Paul John H. , Myers Brenda
Published: January 2020

A method for the determination of microbial DNA in aquatic environments by the use of Hoechst 33258 has been developed. With unsophisticated instrumentation and simple extraction procedures, it is possible to detect from 0.05 to 10 μg of DNA in bacterial cultures or natural water samples. The method is specific for DNA; DNase I treatment of extracts of natural microbial populations removed 95 to 100% of the observed fluorescence. DNA content ranged from 165 ng ml
−1
for relatively eutrophic Potomac River water to 27 ng ml
−1
for coastal Atlantic Ocean water and was correlated to an acridine orange direct count (
r
= 0.90).
Microbial flora of the mouse ileum mucous layer and epithelial surface
Authors: Rozee K R , Cooper D , Lam K , Costerton J W
Published: January 2020

We have developed new methods to minimize fluid shear during preparation of specimens for electron microscopy and to retain the mucous blanket that covers the tissue surface of the ileum in mice. We also used general stabilization by nonspecific antibodies to minimize the collapse of the mucous layer during dehydration for electron microscopy. These methods allowed us to visualize the gradual progression of the mucous blanket from a thin diaphanous layer in newborn animals to a very thick (ca. 50 micrometers), coherent structure in older animals that contained a mixed population of bacteria and protozoa. Some bacteria, notably filamentous forms, were patently anchored to the epithelial tissue but projected into the mucous blanket, whereas others clearly existed within the mucous blanket and were unattached to the epithelial surface. Similarly, some protozoa were firmly attached to the tissue surface, whereas others were suspended in the viscous mucous blanket. In an adult animal, the mucous blanket was a very thick layer which actually occluded most of the tissue surface and contained a rich variety of bacteria and protozoa.
Formation of Crystalline δ-Endotoxin or Poly-β-Hydroxybutyric Acid Granules by Asporogenous Mutants of
Bacillus thuringiensis
Authors: Wakisaka Yoshiharu , Masaki Emiko , Nishimoto Yoji
Published: January 2020

Parental strains and asporogenous mutants of
Bacillus thuringiensis
subspp.
kurstaki
and
aizawai
produced high yields of δ-endotoxin on M medium, which contained 330 μg of potassium per ml, but not on ST and ST-a media, each of which contained only 11 μg of potassium per ml. On ST and ST-a media, refractile granules were formed instead. These granules had no insecticidal activity against silkworms and were isolated and identified as poly-β-hydroxybutyric acid. Supplementation of the potassium-deficient ST-a medium with 0.1% KH
2
PO
4
(3.7 mM) led to the formation of crystalline δ-endotoxin. The replacement of KH
2
PO
4
with equimolar amounts of KCl, KNO
3
, and potassium acetate or an equivalent amount of K
2
SO
4
had a similar effect, whereas the addition of an equimolar amount of NaH
2
PO
4
or NH
4
H
2
PO
4
did not cause the endotoxin to form. An asporogenous mutant,
B. thuringiensis
subsp.
kurstaki
strain 290-1, produced δ-endotoxin on ST-a medium supplemented with 3 mM or more potassium but formed only poly-β-hydroxybutyric acid granules on the media containing ≤1 mM potassium. These results clearly indicate that a certain concentration of potassium is essential for the fermentative production of δ-endotoxin by these isolates of
B. thuringiensis
. Manganese could not be substituted for potassium. Phosphate ions stimulated poly-β-hydroxybutyric acid formation by strain 290-1. The sporulation of
B. thuringiensis
and several other
Bacillus
strains was suppressed on the potassium-deficient ST medium. This suggests that potassium plays an essential role not only in
Bacillus
cell growth and δ-endotoxin formation but also in sporulation.
Thermal Inactivation of a Deep-Sea Barophilic Bacterium, Isolate CNPT-3
Authors: Yayanos A. Aristides , Dietz Allan S.
Published: January 2020

The barophilic deep-sea bacterium, isolate CNPT-3, was inactivated by exposures to temperatures between 10 and 32�C at atmospheric pressure. Inactivation in samples from warmed cell suspensions was measured as the loss of colonyforming ability (CFA) at 10�C and 587 bars. At atmospheric pressure, there was a slow loss of CFA even at 10�C. The loss of CFA was rapid above 20�C and only slightly affected by high pressures. The first-order rate constants for thermal inactivation fit the Arrhenius equation with an activation energy of 43 kcal (ca. 179.9 kJ)/mol. Light microscopy and scanning transmission electron microscopy revealed morphological changes due to warming of the cells. The changes ensued the loss of CFA. The results supported the hypothesis from an earlier work that indigenous (autochthonous) deep-sea bacteria from cold deep seas are both barophilic and psychrophilic. If ultimately sustained, these characteristics may be useful in designing experiments to assess the relative importance of the autochthonous and allochthonous bacteria in the deep sea. The data were used to evaluate how barophilic bacteria may have been missed in many investigations because of warming of the cells during sample retrieval from the sea or during cultivation in the laboratory. The evaluation revealed the need for temperature and pressure data during retrieval of samples and cultivation in the laboratory. Most deep-ocean microbiology may be possible with thermally insulated equipment for retrieval from the sea and with high-pressure vessels for laboratory incubations.
Possible Role of Coryneform Bacteria in Age Gelation of Ultrahigh-Temperature-Processed Milk
Authors: Keogh Barbara P. , Pettingill G.
Published: January 2020

Two strains of psychrotrophic, gram-positive, proteolytic bacteria isolated from raw milk were identified as
Arthrobacter
or closely related coryneform species. We inoculated raw-milk samples with the strains (one strain per sample) and compared rates of gelation after ultrahigh-temperature processing with that of ultrahigh-temperature-processed controls. The trial indicated that either organism could play a role in age gelation of ultrahigh-temperature-processed milk.
Stimulation of Autotrophic Ammonium Oxidation in Rice Rhizosphere Soil by the Insecticide Carbofuran
Authors: Ramakrishna C. , Sethunathan N.
Published: January 2020

The application of the insecticide carbofuran (technical or formulated) to rice rhizosphere soil suspensions at 10 and 100 ppm (μg/ml) of active ingredient distinctly stimulated the autotrophic oxidation of ammonium. Evidence suggested that
Nitrosomonas
sp. was enriched in the presence of carbofuran. Formulated carbofuran (Furadan 3G) exhibited a more pronounced stimulation of ammonium oxidation than that exhibited by technical-grade (99.5%) carbofuran, a result which was attributed to the CaCO
3
present in the formulation.
Influence of high-fiber diet on bacterial populations in gastrointestinal tracts of obese- and lean-genotype pigs
Authors: Varel V H , Pond W G , Pekas J C , Yen J T
Published: January 2020

Bacterial populations from gastrointestinal tracts of genetically lean and obese pigs fed a low- or high-fiber diet (0 or 50% alfalfa meal, respectively) were enumerated with rumen fluid media and specific energy sources. Total culture counts in rectal samples declined 56 (P greater than 0.05) and 63% (P less than 0.05) in lean and obese animals, respectively, 3 weeks after feeding the high-fiber diet. After 8 weeks, culture counts had risen and were similar to those obtained before alfalfa was fed (0 week). At slaughter, 12 to 17 weeks after feeding the high-fiber diet, total counts from rectal samples of lean pigs continued to rise and were 13% greater than the 0-week counts, whereas counts from obese animals declined 37% (P greater than 0.05). The number of cellulolytic bacteria in rectal samples of lean-genotype pigs fed the high-fiber diet increased 80 and 71% from 0 to 3 weeks and 3 to 8 weeks, respectively. This overall increases from 0 to 8 weeks in lean pigs was significant (P less than 0.05); however, these increases were not seen in obese pigs. These data suggest that the microflora is initially suppressed when exposed to a high-fiber diet and that later some adaptation takes place, apparently more so in lean than in obese pigs. When specific energy sources were used to delineate the distribution of different bacterial populations in the cecum, colon, and rectum, trends could be detected between high- and low-fiber diets. These data also support the concept that bacteria populations from different sites in the large bowel differ.
Enhanced biodegradation of methoxychlor in soil under sequential environmental conditions
Authors: Fogel S , Lancione R L , Sewall A E
Published: January 2020

Ring-U-[14C]methoxychlor [1,1-bis(p-methoxyphenyl)-2,2,2-trichloroethane] was incubated in soil under aerobic and anaerobic conditions. Primary degradation of methoxychlor occurred under anaerobic conditions, but not under aerobic conditions, after 3 months of incubation. Analysis of soil extracts, using gas chromatography, demonstrated that only 10% of the compound remained at initial concentrations of 10 and 100 ppm (wt/wt) of methoxychlor. Evidence is presented that a dechlorination reaction was responsible for primary degradation of methoxychlor. Analysis of soils treated with 100 ppm of methoxychlor in the presence of 2% HgCl2 showed that 100% of the compound remained after 3 months, indicating that degradation in the unpoisoned flasks was biologically mediated. Methanogenic organisms, however, are probably not involved, as strong inhibition of methane production was observed in all soils treated with methoxychlor. During the 3-month incubation period, little or no evaluation of 14CO2 or 14CH4 occurred under either aerobic or anaerobic conditions. Cometabolic processes may be responsible for the extensive molecular changes which occurred with methoxychlor because the rate of its disappearance from soil was observed to level off after exhaustion of soil organic matter. After this incubation period, soils previously incubated under anaerobic conditions were converted to aerobic conditions. The rates of 14CO2 evolution from soils exposed to anaerobic and aerobic sequences of environments ranged from 10- to 70-fold greater than that observed for soils exposed solely to an aerobic environment.
Ecological Consequences of Long-Term Exposure of
Anabaena variabilis
(Cyanophyceae) to Shifts in Environmental Factors
Authors: Collins Carol D. , Boylen Charles W.
Published: January 2020

Cultures of
Anabaena variabilis
were exposed to different light intensities, and the time course of photoadaptation was measured by photosynthetic rate and changes in pigmentation. A shift down in intensity of 284 μEin · m
−2
· sec
−1
caused a temporary decrease in the photosynthetic response followed by gradual adaptation to the new conditions. Final chlorophyll
a
and carotenoid concentrations were reached after 1 day, although other physiological indicators showed that adaptation required 4 days. The parameter
I
k
was shown to be the best indicator of photoadaptation. A shift up in light intensity of the same magnitude also required 4 days for complete photoadaptation by the culture, although chlorophyll and carotenoid concentrations stabilized within 1 day. A shift down in light intensity of 392 μEin · m
−2
· sec
−1
resulted in a temporary attempt to adapt followed by collapse of the population. This demonstrates an apparent threshold in the magnitude of the shift in light intensity which will permit successful adaptation. Simultaneous changes in light intensity and temperature also adversely affected culture populations. Our observations present a possible cause for the decline or prevention of an algal bloom under a fluctuating light regime and suggest that it may be possible to predict this decline as a result of synoptic weather patterns or hydrodynamic influences.
Measurement of aquatic biodegradation rates by determining heterotrophic uptake of radiolabeled pollutants
Authors: Pfaender F K , Bartholomew G W
Published: January 2020

The heterotrophic uptake technique was modified to provide a rapid and simple technique for estimating the rates of biodegradation of organic pollutants under environmental conditions. The methodology is based on an evaluation of uptake into cells and subsequent respiration of radiolabeled organic substrates in short-term experiments. The resulting data can be used to calculate either turnover times or, if multiple concentrations of substrate are used, kinetic parameters. The procedure was applied to assess the biodegradation rates of m-cresol, chlorobenzene, nitrilotriacetic acid, and 1,2,4-trichlorobenzene in fresh, brackish, and marine water samples from the coastal areas of North Carolina. Saturation kinetics for uptake were obtained with each of the compounds tested. Rates of metabolism were shown to be dependent on sample location and time of year.
Emulsan in
Acinetobacter calcoaceticus
RAG-1: Distribution of Cell-Free and Cell-Associated Cross-Reacting Material
Authors: Goldman S. , Shabtai Y. , Rubinovitz C. , Rosenberg E. , Gutnick D. L.
Published: January 2020

Emulsan is an extracellular polymeric bioemulsifier produced by
Acinetobacter calcoaceticus
RAG-1. Antibodies prepared against purified emulsan inhibited the activity of the polymer in a standard emulsification test. These antibodies were used to develop a sensitive enzyme-linked immunosorbent assay to monitor changes in cell-free emulsan throughout the growth cycle. This assay was also used to detect emulsan associated with the cell surface and to monitor changes in the distribution of cell-free and cell-associated emulsan throughout the growth cycle. Cells in the early exponential phase exhibited relatively large amounts of cell-associated emulsan which decreased rapidly between the midexponential and early stationary phases. This drop in cell-associated material was accompanied by a rise in the concentration of extracellular polymer. Moreover, in agreement with previous results (C. Rubinovitz, D. L. Gutnick, and E. Rosenberg, manuscript in press), production of cell-free emulsan was enhanced in the presence of chloramphenicol. The release of this material from the cell surface in the presence of chloramphenicol apparently involved the synthesis of cell-associated cross-reacting material since the relative amount of such cell-bound polymer remained constant during the treatment with the drug.
Anaerobic Spirochete from a Deep-Sea Hydrothermal Vent
Authors: Harwood C. S. , Jannasch H. W. , Canale-Parola E.
Published: January 2020

An obligately anaerobic spirochete, designated strain GS-2, was selectively isolated from samples collected at a deep-sea (2,550 m) hydrothermal vent of the Galapagos Rift ocean floor spreading center. The morphological and physiological characteristics of strain GS-2 resembled those of
Spirochaeta
strains. However, strain GS-2 failed to grow consistently in any liquid medium tested. In addition, strain GS-2 grew more slowly and to lower yields than other
Spirochaeta
species. The occurrence of obligately anaerobic bacteria in hydrothermal vents indicates that the water in at least some of the vent areas is anoxic. The presence of strain GS-2 shows that these areas are favorable for anaerobic marine spirochetes.
Specificity of the Westerfeld adaptation of the Voges-Proskauer test
Authors: Speckman R A , Collins E B
Published: January 2020

Aliphatic chain compounds at least four carbons long with vicinal carbonyl groups in the 2,3 positions were detected by the Westerfeld test. Acetoin, which has one carbonyl group and an adjacent hydroxyl group, gave positive results, but methyl action (3-hydroxy-3-methyl-2-butanone) was negative, and subsequent tests supported the conclusion that acetoin is oxidized to diacetyl by alpha-naphthol during the Westerfeld test in the absence or presence of air. 2,3-Pentanedione and 2,3-heptanedione gave positive results, but equimolar concentrations of these compounds gave maximal absorbancy readings that were only 35% (2,3-pentanedione) and 31% (2,3-heptanedione) of those obtained with diacetyl or acetoin. Negative results were obtained with pyruvic acid, 2,3-butylene glycol, and carbon ring compounds (1,2-cyclohexanedione, alloxan, and 3,4-dihydroxy-3-cyclobutene-1,2-dione). alpha-Naphtho could not be replaced in the test by beta-naphthol, 1,2,3,4,-tetrahydroxy-1-naphthol, or 5,6,7,8-tetrahydroxy-1-naphthol. Creatine could not be replaced by arginine, guanidine . HCl, or guanidinoacetic acid.
Microbiological quality of frozen cauliflower, corn, and peas obtained at retail markets
Authors: Barnard R J , Duran A P , Swartzentruber A , Schwab A H , Wentz B A , Read R B
Published: January 2020

The microbiological quality of blanched frozen cauliflower, cut corn, and peas at the retail level was determined. At 35 degrees C, mean aerobic plate count (APC) values for cauliflower, corn, and peas, respectively, were 30,000, 6,100, and 4,700 per g; at 30 degrees C, the mean APC values were 45,000, 8,500, and 6,800 per g, respectively. Geometric means for coliform, Escherichia coli, and Staphylococcus aureus counts for all three vegetables were less than 10 per g.
Biodegradation of 2,4,5-trichlorophenoxyacetic acid by a pure culture of Pseudomonas cepacia
Authors: Kilbane J J , Chatterjee D K , Karns J S , Kellogg S T , Chakrabarty A M
Published: January 2020

A pure culture of Pseudomonas cepacia, designated AC1100, that can utilize 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) as its sole source of carbon and energy was isolated. An actively growing culture of AC1100 was able to degrade more than 97% of 2,4,5-T, present at 1 mg/ml, within 6 days as determined by chloride release, gas chromatographic, and spectrophotometric analyses. The ability of AC1100 to oxidize a variety of chlorophenols and related compounds is also reported.
Synergistic Interaction Between
Anabaena
and
Zoogloea
spp. in Carbon Dioxide-Limited Continuous Cultures
Authors: Schiefer G. E. , Caldwell D. E.
Published: January 2020

Flocs consisting of
Anabaena
and
Zoogloea
spp. were used as a model system for the study of planktonic phototroph-heterotroph interactions. In CO
2
-limited continuous culture (3.2 μmol of NaHCO
3
liter
−1
h
−1
, 1.5 μmol of glucose liter
−1
h
−1
, pH 8.5,
D
= 0.026 h
−1
), the biomass of the phototroph increased 8.6-fold due to association. However, direct CO
2
exchange accounted for only a 3.8-fold increase. When the glucose supply rate was increased to 7.5 μmol liter
−1
h
−1
, there was a 26-fold increase in biomass. When CO
2
was supplied in excess, there was no difference due to association. In batch culture, using the same medium, the specific growth rate was 0.029 h
−1
for the phototroph alone and 0.047 h
−1
for the phototroph in association with the heterotroph. The stimulatory effect of the heterotroph was found only under CO
2
-limiting conditions and was directly related to the concentration of organic matter supplied in the medium. Both the biomass and the growth rate of the
Anabaena
sp. were increased by association with the
Zoogloea
sp. Thus, dissolved organic matter may substitute for CO
2
to maximize both growth rate and biomass production by phototrophs when heterotrophic bacteria are present.