bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Glucose, pH, and Dissolved-Oxygen Tension on
Bacillus cereus
Growth and Permeability Factor Production in Batch Culture
Authors: Spira W. M. , Silverman G. J.
Published: January 2020

The production of a
Bacillus cereus
enterotoxin, measured as rabbit skin permeability factor (PF), in response to differences in glucose availability, pH, and dissolved oxygen tension was studied in a 1-liter batch fermentor system. Glucose had to be present for toxigenesis to occur. In uncontrolled fermentation an increasing inhibition of PF production and growth occurred as pH dropped occurred below 6.5. Optimum pH for toxigenesis was 7.0 to 7.5, and fermentations maintained at this level yielded 10- to 20-fold more PF than comparable uncontrolled fermentations. PF production was appreciably diminished at or below pH 6.0 and at or above pH 8.5. Peak PF titer was associated with a drop in acid output, and the titrant utilization profile could be used as an indication of this point. Productivity was greatest in the early exponential phase of growth and decreased to zero at the transition phase. Differences in dissolved oxygen tension affected both the maximum productivity early in the fermentation and the rate of its decrease as growth progressed. The optimum dissolved oxygen tension for toxigenesis was 0.002 atm, and the most rapid growth occurred at 0.10 atm. Productivity and growth were reduced under anerobic conditions, whereas a hyperoxic environment severely reduced productivity, but not growth. Postexponential-phase loss of toxic activity coincided with a rapid increase in cellular oxygen demand. Neither was inhibited by the presence of glucose. However, PF loss was completely prevented by stringent oxygen limitation. Extracellular proteolytic activity did not appear to be responsible for the loss of toxic activity.
Moniliformin, a metabolite of Fusarium moniliforme NRRL 6322: purification and toxicity
Authors: Burmeister H R , Ciegler A , Vesonder R F
Published: January 2020

Fusarium moniliforme NRRL 6322 produced about 600 mg of recoverable moniliformin, a mycotoxic metabolite, per kg of corn grit medium. The moniliformin was extracted from the grits with methanol, purified by preparative thin-layer chromatography, and crystallized from ether. The 50% lethal dose for chicken embryos was 2.8 microgram per egg. For 1-day-old chicks dosed with moniliformin by crop intubation and for female and male mice injected intraperitoneally, the 50% lethal doses were 5.4, 20.9, and 29.1 mg per kg of body weight, respectively. The toxin did not cause a reaction on mouse skin.
Electrode System for the Determination of Microbial Populations
Authors: Matsunaga Tadashi , Karube Isao , Suzuki Shuichi
Published: January 2020

Determinations of microbial populations were carried out by using a new electrode system composed of two electrodes. Each electrode was constructed from a platinum anode and a silver peroxide cathode. The anode of the reference electrode was covered with cellulose dialysis membrane. The response time of the electrode system was 15 min in culture broth, and current differences between the two electrodes were proportional to populations of microbial cells in cultures of
Saccharomyces cerevisiae
and
Lactobacillus fermentum
. Current differences were reproducible; the average relative error was 5%. Furthermore, cell populations of
S. cerevisiae
in a fermentor could be continuously estimated by using this electrochemical method.
Isolation and characterization of large treponemes from the bovine rumen
Authors: Ziołecki A
Published: January 2020

Ten strains of strictly anaerobic spiral organisms were isolated in pure culture from a 10(-7) dilution of bovine rumen contents. Three strains were studied in detail. These strains morphologically resembled previously isolated and described rumen treponemes except the new isolates were larger, 0.7 micrometer wide and 12 to 25 micrometer long. They rapidly fermented pectin and, less readily, L-arabinose, inulin, and sucrose. Acetic and formic acid were the main fermentation products from pectin; small amounts of succinic acid were also formed.
Germ Tube Growth Inhibitor from
Cronartium comandrae
Aeciospores
Authors: Eppstein Deborah A. , Tainter F. H.
Published: January 2020

Two compounds showing self-inhibitory action during germination of aeciospores of the comandra blister rust fungus (
Cronartium comandrae
Pk.) were extracted from these aeciospores by shaking with 0.2 M NH
4
HCO
3
(pH 7.8) for 4 h. One of these, the germination self inhibitor (D. A. Eppstein and F. H. Tainter, Phytopathology
66
:1395-1397, 1976), was removed from the ammonium bicarbonate buffer by using chloroform. The water layer which remained contained a substance which, at ca. 10
−4
M concentration, had no apparent effect on germ tube emergence but which inhibited normal germ tube growth. Linear germ tube growth ceased or a dendritic or vesicular pattern of growth resulted, depending on the concentration of inhibitor added to extracted germinating spores. The germ tube growth inhibitor appears to be a peptide with a molecular weight of ca. 2,000.
Tremorgenic toxins produced by soil fungi
Authors: Patterson D S , Roberts B A , Shreeve B J , MacDonald S M , Hayes A W
Published: January 2020

Penitrem A or an unknown tremorgenic toxin, "X," was produced by 10 of 60 fungal isolates obtained from a pasture involved in an outbreak in cattle and sheep resembling migram and ryegrass staggers. Tremorgenic properties of extracts containing penitrem A or toxin X were confirmed by bioassay.
Selective antibacterial action of 2-mercaptoethanol on propionibacteria in skin cultures
Authors: Mattern K L , Evans C A , Lara J C
Published: January 2020

2-Mercaptoethanol applied to the surface of agar medium had a selective antibacterial effect on Propionibacterium acnes and Propionibacterium granulosum without interfering with the growth of Peptococcus saccharolyticus or staphylococci in anaerobic cultures of skin or in pure cultures. In aerobic broth culture, 2-mercaptoethanol inhibited aerobes and stimulated anaerobes, consistent with its action as a reducing agent.
Production of surface-active lipids by Corynebacterium lepus
Authors: Cooper D G , Zajic J E , Gerson D F
Published: January 2020

Corynebacterium lepus was grown in 20-liter batch fermentations with kerosene as the sole carbon source. Critical micelle concentration measurements indicated the production of appreciable quantities of biosurfactants. This surface activity of the culture medium was due to lipids, which were extracted and identified. Samples of C. lepus whole broth were taken during a fermentation and monitored for surface tension, amount of surfactant present, and lipid content. The changes in the surfactant measured correlated with concentration changes of several surface-active lipids. An early dramatic increase in surfactant concentration was attributed to the production of a mixture of corynomycolic acids (beta-hydroxy alpha-branched fatty acids). Surface activity at the end of the fermentation was due to a lipopeptide containing corynomycolic acids plus small amounts of several phospholipids and neutral lipids which were identified by thin-layer chromatography.
Radiation Resistance and Injury of
Yersinia enterocolitica
Authors: El-Zawahry Yehia A. , Rowley D. B.
Published: January 2020

The
D
values of
Yersinia enterocolitica
strains IP134, IP107, and WA, irradiated at 25�C in Trypticase soy broth, ranged from 9.7 to 11.8 krad. When irradiated in ground beef at 25 and −30�C, the
D
value of strain IP107 was 19.5 and 38.8 krad, respectively. Cells suspended in Trypticase soy broth were more sensitive to storage at −20�C than those mixed in ground beef. The percentages of inactivation and of injury (inability to form colonies in the presence of 3.0% NaCl) of cells stored in ground beef for 10 days at −20�C were 70 and 23%, respectively. Prior irradiation did not alter the cell's sensitivity to storage at −20�C, nor did storage at −20�C alter the cell's resistance to irradiation at 25�C. Added NaCl concentrations of up to 4.0% in Trypticase soy agar (TSA) (which contains 0.5% NaCl) had little effect on colony formation at 36�C of unirradiated
Y. enterocolitica.
With added 4.0% NaCl, 79% of the cells formed colonies at 36�C; with 5.0% NaCl added, no colonies were formed. Although 2.5% NaCl added to ground beef did not sensitize
Y. enterocolitica
cells to irradiation, when added to TSA it reduced the number of apparent radiation survivors. Cells uninjured by irradiation formed colonies on TSA when incubated at either 36 or 5�C. More survivors of an exposure to 60 krad were capable of recovery and forming colonies on TSA when incubated at 36�C for 1 day than at 5�C for 14 days. This difference in count was considered a manifestation of injury to certain survivors of irradiation.
Increased Susceptibility of Rainbow Trout to Infectious Hematopoietic Necrosis Virus After Exposure to Copper
Authors: Hetrick Frank M. , Knittel Martin D. , Fryer J. L.
Published: January 2020

Exposure of rainbow trout to sublethal levels of copper in water increased their susceptibility to infectious hematopoietic necrosis virus. In most instances, the percent mortality was twice as great in the stressed groups compared with those groups which were not stressed but received the same virus dose. Although the level of copper in the water influenced the mortality rates, the length of exposure did not prove to be critical, as similar results were obtained after 1, 3, 5, 7, or 9 days of exposure. When different virus challenges were employed, the percent mortalities were again greater in the stressed fish at all virus doses tested, and at one dose level mortalities were noted in the stressed group but not in the untreated group.
Extraction and Quantification of Solutes in Solidified Agar Culture Media
Authors: Buynitzky Stephen J. , Howe H. Branch , Shellhorse Yovonne
Published: January 2020

A method is described for determining the concentration of certain solutes in solidified culture media. The method is based upon the finding that under specified conditions the concentration of solute in an agar gel (

C
g

) is related to the concentration of solute in a centrifugally extracted gel supernatant (

C
s

) by the ratio,
C
g
/
C
s
, which is characteristic for each solute. The method avoids direct assays of the gels and instead involves assaying the supernatants from inoculated and uninoculated (control) gels with conventional liquid assay techniques and then calculating solute concentrations in the inoculated gels by use of the

C
g

/

C
s

ratios determined from the controls. Uninoculated agar gels containing known concentrations of various solutes and similar gels inoculated with
Neurospora crassa
or
Escherichia coli
were centrifuged at various times, and the supernatants were assayed for solute concentrations. The solute concentrations in the supernatants from the inoculated gels multiplied by the

C
g

/

C
s

ratios for those solutes determined at the same times for the uninoculated controls gave calculated solute concentrations in the inoculated gels. The differences between these calculated solute concentrations and those initially present in the inoculated gels indicated the amounts of solutes utilized from the gels by the microorganisms at various incubation times.
Determination of the Carbon-Bound Electron Composition of Microbial Cells and Metabolites by Dichromate Oxidation
Authors: Harris Robin F. , Adams Susan S.
Published: January 2020

The applicability of the silver sulfate-acid dichromate oxidation (chemical oxygen demand) method for determining the carbon-bound electron compositions of microbial cells, substrates, and metabolic by-products was evaluated. An approach for approximating the carbon-bound electron composition of microbial cells from CHN data is also presented. Ten aliphatic and aromatic carboxylic acids, 17 amino acids, and 8 sugars generally gave 96 to 101% (mainly ≥98%) recovery with 0.0625 N dichromate (digestion mixture of 10 ml of sample-10 ml of 0.25 N dichromate-20 ml of Ag
2
SO
4
-amended concentrated H
2
SO
4
). Recoveries of nicotinic acid (5%) and methionine (65%) were incomplete; arginine (125%) and two purine and three pyrimidine bases (105 to 120%) were overestimated. The validity of 0.0625 N dichromate for determining the carbon-bound electron composition of bacterial cells was supported by theoretical analysis of the carbon-bound electron composition of hypothetical bacterial cell material (defined monomer composition) and by the compatibility of elemental and dichromate oxidation-derived carbon-bound electron compositions of typical bacterial cells.
Tandem Coagulase/Thermonuclease Agar Method for the Detection of
Staphylococcus aureus
Authors: Boothby J. , Genigeorgis C. , Fanelli M. J.
Published: January 2020

In optimizing previously reported coagulase agar media to obtain a rapid, reliable, and inexpensive coagulase test agar, variations in plasmas, pH, buffer system, fibrinogen, and fibrinolytic inhibitor were investigated. The agar with the following composition was determined best for the demonstration of coagulase production by
Staphylococcus aureus
: 25 ml of 15% bovine fibrinogen (fraction I, type I, citrated, Sigma Chemical Co.), 25 ml of rehydrated rabbit plasma (coagulase plasma ethylenediaminetetraacetic acid, Difco), 10.0 mg of soybean trypsin inhibitor (Schwarz/Mann), and 450 ml of brain heart infusion agar (Difco). In additional studies involving 7 different temperatures and 11 heating times, the thermal destruction of microbial nucleases on plate count agar and coagulase test agar was investigated. Heating the plates for 2.5 h at 65°C destroyed all heatlabile nucleases, but not thermonucleases of
S. aureus.
A tandem agar plate method for the identification of
S. aureus
was developed. Coagulase and thermonuclease activity of 50 colonies can be detected on a single agar plate. Suspect
S. aureus
colonies isolated on various selective media are transferred to coagulase test agar, the plates are incubated at 37°C for 18 h, and the coagulase reaction is recorded. The plates are then heated at 65°C for 2.5 h, overlaid with toluidine blue-metachromatic diffusion agar, and reincubated at 37°C for 3 h, and the thermonuclease reaction is recorded. Studies based on 88 enterotoxigenic
S. aureus
strains and 133 and 48 suspect
S. aureus
strains isolated from fresh salami mixtures on mannitol salt and tellurite-polymyxin-egg yolk agars, respectively, demonstrated 100% agreement between the tandem agar plate method and standard coagulase and thermonuclease tests. Overall, the tandem agar plate method is a rapid and convenient approach contributing to the identification of
S. aureus
from foods.
Differentiation of aflatoxins from territrems
Authors: Ling K H , Yang C K , Huang H C
Published: January 2020

Three methods were adopted for differentiation of aflatoxins B1 and B2 from territrems A and B. They were as follows. (i) Then-layer chromatography coupled with chemical confirmation. A significant decrease in the Rf value of trifluoroacetic acid-treated aflatoxin B1 developed in chloroform-acetone (85:15, vol/vol) was satisfactory in differentiating this toxin from the other three. (ii) High-pressure liquid chromatography monitored synchronously at two wavelengths, 365 and 335 nm. The ratio derived from this double-wavelengh detection could serve as an indicator of the presence of each toxin. (iii) Velasco's flurotoxin meter method, which is used for the determination of aflatoxins within the range of 0 to 50 ng/ml, was not significantly affected by territrems even when they were present in quantities at the microgram-per-milliliter level.
Grouping of Lactic Streptococci by Gel Electrophoresis of Soluble Cell Extracts
Authors: Jarvis A. W. , Wolff J. M.
Published: January 2020

Soluble cell proteins obtained from 35 strains of lactic streptococci were examined by gel electrophoresis. A mathematical analysis of the densitometer scans of the gels enabled strains to be grouped according to their overall similarity. Strains which were known to be variants of the same parent strain fell into the same group, supporting the validity of the method. It is suggested that strains which are alike according to their gel electrophoretic patterns when grown under standard conditions have an overall phenotypic similarity and that this indicates a similarity in genotype. The relevance of this to selection of strains of lactic streptococci for cheesemaking is discussed.
Spoilage association of chicken skin
Authors: Daud H B , McMeekin T A , Thomas C J
Published: January 2020

The bacterial succession on the skin of broiler chicken carcasses stored at 2 degrees C was traced, and the ability of representative isolates to produce off-odors was determined by using sterile leg and breast muscle sections. Off-odors were identified by olfactory and chemical means. The inability of peptone-iron agar to detect sulfide-producing strains was noted.
Thermal stress of Pseudomonas fluorescens in complex media
Authors: McCoy D R , Ordal Z J
Published: January 2020

Pseudomonas fluorescens (P7) cells were stressed by incubation at 43 degrees C for 2 h. The stress induced a 9-h lag in replication after the return of the temperature of the culture to 25 degrees C. Stressed cells demonstrated a sensitivity to diluents and plating media during the recovery period. Data from utilization of selective inhibitors suggested that ribonucleic acid and protein, but not deoxyribonucleic acid, syntheses were required for recovery by the cells. The cells lost uracil- and leucine-labeled material as a result of the stress, further suggesting that ribonucleic acid and protein damage had occurred. Membrane damage was indicated by sensitivity to sodium dodecyl sulfate near the end of the lag period. Membrane damage was also suggested by the failure of cells to incorporate labeled material from the recovery medium. The lesions induced in this foodlike system are compared with those previously reported for a minimal media model system (Gray et al., Appl. Microbiol. 26:78-85, 1973; Gray et al., Appl. Environ. Microbiol. 33:1074-1078, 1977).
Degradation of poliovirus by adsorption on inorganic surfaces
Authors: Murray J P , Laband S J
Published: January 2020

Alteration of the specific infectivity of 3H-labeled ribonucleic acid and 14C-protein labeled poliovirus type 1 by adsorption on inorganic surfaces is investigated by application of kinetic theory to data obtained from sequential extractions of adsorbed virus. Some surfaces, e.g., SiO2, appear to have no significant effect. On the other hand, CuO substantially decreases the specific infectivity of adsorbed preparations. Differences in kinetic plots between 3H-labeled ribonucleic acid and 14C-labeled protein suggest that the inactivation observed involves physical disruption of virions. Van der Waals interactions between solid surfaces and virus are suspected to induce spontaneous virion disassembly. Surface catalyzed disassembly in aquatic and soil environments is implicated as an important mechanism controlling enterovirus dissemination. Methods developed here to evaluate complete recovery of adsorbed virus have potenital application to other degradation studied and problems concerning virus recovery from adsorbents used in virus concentrators.
Automated electrical impedance technique for rapid enumeration of fecal coliforms in effluents from sewage treatment plants
Authors: Silverman M P , Munoz E F
Published: January 2020

Fecal coliforms growing in a selective lactose-based broth medium at 44.5 degrees C generate a change in the electrical impedance of the culture relative to a sterile control when populations reach 10(6) to 10(7) per ml. The ratio of these changes was measured automatically, and the data were processed by computer. A linear relation was found between the log10 of the number of fecal coliforms in an inoculum and the time required for an electrical impedance ratio signal to be detected. Pure culture inocula consisting of 100 fecal coliforms in log phase or stationary phase were detected in 6.5 and 7.7 h, respectively. Standard curves of log10 fecal coliforms in wastewater inocula versus detection time, based on samples collected at a sewage treatment plant over a 4-month period, were found to vary from one another with time. Nevertheless, detection times were rapid and ranged from 5.8 to 7.9 h for 200 fecal coliforms to 8.7 to 11.4 h for 1 fecal coliform. Variations in detection times for a given number of fecal coliforms were also found among sewage treatment plants. A strategy is proposed which takes these variations into account and allows for rapid, automated enumeration of fecal coliforms in wastewater by the electrical impedance ratio technique.
Rapid, single-step most-probable-number method for enumerating fecal coliforms in effluents from sewage treatment plants
Authors: Munoz E F , Silverman M P
Published: January 2020

A single-step most-probable-number method for enumerating fecal coliforms in sewage treatment plant effluents is described. The method requires the use of only one lactose-based medium and a single incubation temperature of 44.5 degrees C, and it can be completed in 18 h or less, as compared with up to 72 h for the standard most-probable-number method. The appearance of growth is the sole criterion used for designating positives, which can be determined either by increases in the electrical impedance ratio of inoculated medium, as compared to an uninoculated control using a Bactometer model 32, or by visual examination of inoculated medium for turbidity. In trials with 53 samples of unchlorinated sewage treatment plant effluent, fecal coliform counts by the single-step most-probable-number method, throughout a range of less than 10 to almost 10(7) fecal coliforms per 100 ml of effluent, were in excellent agreement with counts abtained by the standard most-probable-number procedure. Similar agreement was obtained in comparative trials with 31 chlorinated effluent samples from two sewage treatment plants. Overall, 87% of 452 positives were confirmed as containing fecal coliforms. The applicability of the single-step most-probable-number method to automated sewage treatment plant operations is discussed.
Mechanism of lethal action of 2,450-MHz radiation on microorganisms
Authors: Vela G R , Wu J F
Published: January 2020

Various bacteria, actinomycetes, fungi, and bacteriophages were exposed to microwaves of 2,450 +/- 20 MHz in the presence and in the absence of water. It was found that microorganisms were inactivated only when in the presence of water and that dry or lyophilized organisms were not affected even by extended exposures. The data presented here prove that microorganisms are killed by "thermal effect" only and that, most likely, there is no "nonthermal effect"; cell constituents other than water do not absorb sufficient energy to kill microbial cells.
Mycological survey of selected health foods
Authors: Mislivec P B , Bruce V R , Andrews W H
Published: January 2020

A survey was conducted to compare the total viable fungal content and the number of different mold species encountered in 10 types of health foods labeled organically grown and in the same foods without such a label. The foods were wheat flour, corn meal, brown rice, figs, split peas, pinto beans, soybeans, walnuts, pecans, and peanuts. Results showed no consistent difference in either the total viable fungal content or the number of different mold species encountered between the labeled and unlabeled foods. Two genera of yeasts (Rhodotorula and Saccharomyces) and 22 gener of molds, including more than 65 species, were encountered. The mold flora was dominated by Aspergillus glaucus, Aspergillus niger, Aspergillus flavus, Aspergillus candidus, Penicillium cyclopium, and Penicillium viridicatum. Isolates of the genera Alternaria, Cladosporium, Fusarium, and Helminthosporium also occurred in certain foods. At least 10 toxicogenic species of Aspergillus and Penicillium were encountered. A total of 87 cultures of these species, all isolated from health foods, were screened for laboratory production of their respective toxins. Toxin production potential of these 87 cultures did not differ from that of cultures of the same species isolated from conventional foods.
Human enteroviruses in oysters and their overlying waters
Authors: Goyal S M , Gerba C P , Melnick J L
Published: January 2020

The presence of enteroviruses in oysters and oyster-harvesting waters of the Texas Gulf coast was monitored over a period of 10 months. Viruses were detected in water and oyster samples obtained from areas both open and closed to shellfish harvesting. Viruses were detected periodically in waters that met current bacteriological standards for shellfish harvesting. No significant statistical relationship was demonstrated between virus concentration in oysters and the bacteriological and physiochemical quality of water and shellfish. Viruses in water were, however, moderately correlated with total coliforms in water and oysters and with fecal coliforms in oysters. Total coliforms in water were realted to total coliforms in sediment were related only to total coliforms in sediment. Among the physiochemical characteristics of water, turbidity was related statistically to the organic matter content of water and to fecal coliforms in water. There was a marked effect of rainfall on the bacteriological quality of water. Of a total of 44 water samples, 26 yielded virus in concentrations from 4 to 167 plaque-forming units per 100-gallon (ca. 378.5-liter) sample. Of a total of 40 pools of 10 to 12 oysters each, virus was found in 14 pools at a concentration of 6 to 224 plaque-forming units per 100 g of oyster meat. On five occasions, virus was found in water samples when no virus could be detected in oysters harvested from the same sites. This study indicates that current bacteriological standards for determining the safety of shellfish and shellfish-growing waters do no reflect the occurrence of enteroviruses.
Concentration of poliovirus from tap water using positively charged microporous filters
Authors: Sobsey M D , Jones B L
Published: January 2020

Microporous filters that are more electropositive than the negatively charged filters currently used for virus concentrations from water by filter adsorption-elution methods were evaluated for poliovirus recovery from tap water. Zeta Plus filters composed of diatomaceous earth-cellulose-"charge-modified" resin mixtures and having a net positive charge of up to pH 5 to 6 efficiently adsorbed poliovirus from tap water at ambient pH levels 7.0 to 7.5 without added multivalent cation salts. The adsorbed virus were eluted with glycine-NaOH, pH 9.5 to 11.5. Electropositive asbestos-cellulose filters efficiently adsorbed poliovirus from tap water without added multivalent cation salts between pH 3.5 and 9.0, and the absorbed viruses could be eluted with 3% beef extract, pH 9, but not with pH 9.5 to 11.5 glycine-NaOH. Under water quality conditions in which poliovirus recoveries from large volumes of water were less than 5% with conventional negatively charged filters and standard methods, recoveries with Zeta Plus filters averaged 64 and 22.5% for one- and two-stage concentration procedures, respectively. Electropositive filters appear to offer distinct advantages over conventional negatively charged filters for concentrating enteric viruses from water, and their behavior tends to confirm the importance of electrostatic forces in virus recovery from water by microporous filter adsorption-elution methods.
Comparative study on the antimicrobial effect of 0.5% chlorhexidine gluconate and 70% isopropyl alcohol on the normal flora of hands
Authors: Aly R , Maibach H I
Published: January 2020

A gloved-hand wash method was used to compare the antimicrobial effect of chlorhexidine gluconate alcohol emollient hand wash (HIBISTAT) with that of 70% isopropyl alcohol on the normal flora of the hands (81 subjects) under conditions designed to mimic use by surgeons. Results of the immediate postwash effects on the bacterial counts for all 3 tests days showed that chlorhexidine significantly reduced the normal flora of the hands. When compared with the base line bacterial counts, there was 85, 96, and 98% reduction with chlorhexidine treatment and 84, 93, and 90% reduction with alcohol treatment on days 1,2, and 5, respectively. The difference between chlorhexidine and alcohol treatments was not statistically significant on days 1 and 2, but was significant on day 5 (P less than 0.01). For delayed postwash bacterial counts (for persistent antimicrobial effects), the overall log means were 4.9943 and 5.4684 for chlorhexidine and alcohol treatments, respectively. The difference between the two treatments was significant (P less than 0.01). After the chlorhexidien treatment, there was no significant growth of bacteria over a period of 6 h when compared with the base line bacterial counts.
Catabolism of protocatechuate by Bacillus macerans
Authors: Crawford R L , Bromley J W , Perkins-Olson P E
Published: January 2020

An aerobic endospore-forming bacterium, tentatively identified as a strain (JJ-lb) of Bacillus macerans, was isolated by enrichment on 4-hydroxybenzoate (4HBA), using as an inoculum soil taken from a 50 degrees C Iadho hot spring. Enzymatic analyses of cells grown on succinate and 4HBA indicated that strain JJ-1b degrades 4HBA by way of the novel protocatechuate (PCA) 2,3-dioxygenase pathway. Purification of the PCA 2,3-dioxygenase by affinity chromatography allowed the first observation of the immediate ring fission product of PCA, namely, 5-carboxy-2-hydroxymuconic semialdehyde (CHMS; labmda max at pH 7.0 = 348 nm). An affinity column fraction was obtained that decarboxylated CHMS to 2-hydroxymuconic semialdehyde (HMS; lambdamax at pH 7.0 = 375 nm). Thus, conversion of PCA to HMS is accomplished in two steps, 2,3-fission of the PCA ring followed by enzymatic decarboxylation of the ring fission product, forming HMS.
Chlorine injury and the enumeration of waterborne coliform bacteria
Authors: Camper A K , McFeters G A
Published: January 2020

Injury induced in Escherichia coli cells by chlorination was studied from a physiological standpoint. Predictable and reproducible injury was found to occur rapidly in 0.5 mg of chlorine per liter and was reversible under nonselective conditions. There was an extended lag period in the growth of chlorinated cells not seen in control suspensions followed by the resumption of logarithmic growth at a rate equaling that of control cells. The aldolase activity of cells chlorinated in vivo was equivalent to that obtained for control cells. Oxygen uptake experiments showed that chlorinated cells underwent a decrease in respiration that was not immediatedly repaired in the presence of reducing agents. This effect was more pronouned in rich media containing reducing agents. Uptake of metabolities was inhibited by chlorine injury as shown with experiments using 14C-labeled glucose and algal protein hydrolysate.
Demonstration of invasiveness of Vibrio parahaemolyticus in adult rabbits by immunofluorescence
Authors: Boutin B K , Townsend S F , Scarpino P V , Twedt R M
Published: January 2020

To determine possible pathogenesis of Vibrio parahaemolyticus-host-organ system interactions, studies of invasiveness were made by a direct fluorescent-antibody method. Broth cultures of live cells isolated from seafish or symptomatic humans were inoculated separately into ligated ileal loops of young New Zealand white rabbits. After suitable incubation, rabbits were sacrificed, and ileal loops and tissue specimens were aseptically removed. Ileal loops were prepared and stained with specific fluorescein-tagged antibody, and organ specimens were cultured for isolation of the inoculated Vibrio strain. All strains tested penetrated into the lamina propria of the ileum and were isolated from the cultured tissue specimens, indicating that the organism is capable of more than a superficial colonization of the gut. The presence of Vibrio in cultured tissue specimens suggests invasion of deeper tissue by either the lymphatic or the circulatory system.
Passage and Survival of Chlamydospores of
Phytophthora cinnamomi
Rands, the Causal Agent of Forest Dieback Disease, Through the Gastrointestinal Tracts of Termites and Wild Birds
Authors: Keast D. , Walsh Leonie G.
Published: January 2020

Chlamydospores of
Phytophthora cinnamomi
Rands have been shown to survive in the intestinal tracts of termites (
Nasutitermes exitiosus
) and two species of forest birds indigenous to West Australian jarrah forests. Viable chlamydospores were recovered from bird feces within the normal rate of passage time for food through the gut. The above factors would allow these creatures to function as vectors for the spores.
Comparative study of the aerobic, heterotrophic bacterial flora of Chesapeake Bay and Tokyo Bay
Authors: Austin B , Garges S , Conrad B , Harding E E , Colwell R R , Simidu U , Taga N
Published: January 2020

A comparative study of the bacterial flora of the water of Chesapeake Bay and Tokyo Bay was undertaken to assess similarities and differences between the autochthonous flora of the two geographical sites and to test the hypothesis that, given similarities in environmental parameters, similar bacterial populations will be found, despite extreme geographic distance between locations. A total of 195 aerobic, heterotrophic bacterial strains isolated from Chesapeake Bay and Tokyo Bay water were examined for 115 biochemical, cultural, morphological, nutritional, and physiological characters. The data were analyzed by the methods of numerical taxonomy. From sorted similarity matrices, 77% of the isolates could be grouped into 30 phena and presumptively identified as Acinetobacter-Moraxella, Caulobacter, coryneforms, Pseudomonas, and Vibrio spp. Vibrio and Acinetobacter species were found to be common in the estuarine waters of Chesapeake Bay, whereas Acinetobacter-Moraxella and Caulobacter predominated in Tokyo Bay waters, at the sites sampled in the study.
Secondary selective enrichment of salmonellae from naturally contaminated specimens by using a selective motility system
Authors: Smeltzer T I , Duncalfe F
Published: January 2020

A selective motility medium was used as a secondary selective enrichment medium to examine specimens naturally contaminated with salmonellae. The medium, incubated at 37 degrees C, was inoculated from either selenite brilliant green sulfa enrichment broth or M�ller-Kauffman tetrathionate broth, both of which had been incubated at 42 degrees C. The use of the selective motility medium resulted in an increase in the number of positive specimens from 65 and 74% to 80 and 82%, when inoculated at 24 and 48 h, respectively, from tetrathionate broth. Tetrathionate broth, when used singly, was significantly better than selenite brilliant green sulfa broth, which detected 55% of positive specimens at both 24 and 48 h. The use of the selective motility medium of Harper and Shortridge (J. Hyg. 67: 181--186, 1969) for the further examination of specimens culturally negative on primary selective enrichment is advocated.
Genetic Evidence for Plasmid-Linked Lactose Metabolism in
Streptococcus lactis
subsp.
diacetylactis
Authors: Kempler G. M. , McKay L. L.
Published: January 2020

It has been previously observed that loss of plasmid pGK4101 occurred concomitantly with loss of lactose-fermenting ability in
Streptococcus lactis
subsp.
diacetylactis
18-16. Transfer of this 41-megadalton plasmid to LM0230, a lactosenegative (Lac
−
) strain of
S. lactis
, required cell-to-cell contact and resulted in a conversion of LM0230 to the Lac
+
phenotype. This confirms the linkage of lactose-fermenting ability to the 41-megadalton plasmid in
S. lactis
subsp.
diacetylactis
and, in addition, demonstrates transfer by a process resembling conjugation in the group N streptococci.
Heterotrophic Uptake Experiments with
14
C-Labeled Histidine in a Histidine-Limited Chemostat
Authors: Sepers Antonie B. J. , Van Es Frank B.
Published: January 2020

The histidine uptake by bacterial strain HIS 42 was determined with [
U
-
14
C]histidine and through oxygen uptake experiments on samples taken from a histidine-limited chemostat. The uptake of [
U
-
14
C]histidine was characterized by a saturation constant of 12.8 to 78.6 nM histidine. At higher growth rates, the measured maximum uptake rate of histidine was lower than the actual uptake rate in the culture. The percentage of respired substrate (76 to 93%) was about 30 to 40% higher than the comparable value for the culture. The uptake of histidine as analyzed through the measurement of oxygen uptake rates was characterized by a saturation constant of 1.7 to 10.5 μM histidine; the maximum uptake rate was always greater than the actual histidine uptake rate in the culture. By the application of the two cited methods, set up to determine the histidine uptake kinetics, two different uptake processes were analyzed. It appeared that the determination of the histidine uptake through measurement of the oxygen uptake rate showed a better reflection of the actual uptake process of histidine in the culture. With the available data it was impossible to assess a correlation between the uptake of histidine, as determined with [
U
-
14
C]histidine, and the actual metabolism of the bacterial population.
Growth and Polysaccharide Production by
Methylocystis parvus
OBBP on Methanol
Authors: Hou C. T. , Laskin A. I. , Patel R. N.
Published: January 2020

Methylocystis parvus
OBBP, an obligate methylotroph originally isolated as a methane-utilizing bacterium, was cultivated on methanol as a sole source of carbon. After adaptation to high methanol levels, this organism grew on methanol with a maximum specific growth rate of 0.65 h
−1
. The pH optimum for growth was between 7 and 9, and the temperature optimum was between 30 and 37°C. Methanol concentrations higher than 5% (by weight) were toxic. Formaldehyde, at a concentration greater than 1 mM, inhibited growth. Formate was neither a substrate nor an inhibitor. An extracellular viscous heteropolysaccharide was produced during growth. The maximum production of the total biomass was 14.5 g (dry weight) per liter of broth. The dried biomass contained 22% (wt/wt) crude protein and 62% (wt/wt) polysaccharide. The main components of the polysaccharide were
d
-glucose (82%) and
l
-rhamnose (14%).
Decomposition of Blue-Green Algal (Cyanobacterial) Blooms in Lake Mendota, Wisconsin
Authors: Fallon Robert D. , Brock Thomas D.
Published: January 2020

Decomposition of natural populations of Lake Mendota phytoplankton dominated by blue-green algae (cyanobacteria) was monitored by using oxygen uptake and disappearance of chlorophyll, algal volume (fluorescence microscopy), particulate protein, particulate organic carbon, and photosynthetic ability (
14
CO
2
up-take). In some experiments, decomposition of
14
C-labeled axenic cultures of
Anabaena
sp. was also measured. In addition to decomposition, mineralization of inorganic nitrogen and phosphorus were followed in some experiments. Decomposition could be described as a first-order process, and the rate of decomposition was similar to that found by others using pure cultures of eucaryotic algae. Nitrogen and phosphorus never limited the decomposition process, even when the lake water was severely limited in soluble forms of these nutrients. This suggests that the bacteria responsible for decomposition can obtain all of their key nutrients for growth from the blue-green algal cells. Filtration of lake water through plankton netting that removed up to 90% of the algal biomass usually did not cause a similar decrease in oxygen demand, suggesting that most of the particulate organic matter used for respiration of the decomposing bacteria was in a small-particle fraction. Short-term oxygen demand correlated well with the particulate chlorophyll concentration of the sample, and a relationship was derived that could be used to predict community respiration of the lake from chlorophyll concentration. Kinetic analysis showed that not all analyzed components disappeared at the same rate during the decomposition process. The relative rates of decrease of the measured parameters were as follows: photosynthetic ability > algal volume > particulate chlorophyll > particulate protein. Decomposition of
14
C-labeled
Anabaena
occurred at similar rates with aerobic epilimnetic water and with anaerobic sediment, but was considerably slower with anaerobic hypolimnetic water. Of the various genera present in the lake,
Aphanizomenon
and
Anabaena
were more sensitive to decomposition than was
Microcystis.
In addition to providing a general picture of the decomposition process, the present work relates to other work on sedimentation to provide a detailed picture of the fate of blue-green algal biomass in a eutrophic lake ecosystem.
Adenosine 5′-Triphosphate Flux Through the North Inlet Marsh System
Authors: Chrzanowski Thomas H. , Stevenson L. Harold , Kjerfve Bjorn
Published: January 2020

The distribution, fluctuation, and short-term transport of total microbial biomass (measured as adenosine 5′-triphosphate [ATP]) was investigated in a large salt marsh creek. Hourly samples were collected synoptically for 25 h from 10 boats positioned across the 320-m width of the creek. Samples were collected from three depths ranging from 0.2 to 8.0 m. Hourly data obtained from each station were graphed, plotting depth against ATP. Subsequently, interpolated ATP values were generated for every one-tenth depth from the surface to the bottom with the use of an 11-point proportional divider. A total of 2,750 values were generated, and a mean value of 0.865 mg of ATP per m
3
was determined. Maximum levels of ATP were found at high tide and minimal values were found at low tide. The distribution of ATP concentrations was found to be complex, with no suggestion of vertical stratification; however, horizontal divisions were apparent. ATP values corrected for direction of flow or velocity indicated two ebb-directed channels; however, when considered in total, there was a net import of ATP through the interface. The total import of ATP for this 25-h sampling period was calculated to be 3.58 kg, corresponding to a net transport of 39.8 mg of ATP per s through the cross section. Results suggest that detailed characterization of a creek transect in terms of ATP or any similar parameter requires the simultaneous measurements of both the concentration of the parameter in question and the velocity at the time and point from which the sample was taken.
Transfer of R factors to and between genetically marked sublines of Rhizobium japonicum
Authors: Kuykendall L D
Published: January 2020

Plasmids R1822 and pRD1 of the P-1 incompatibility group, for which Rhizobium japonicum had not previously been shown to serve as host, were introduced into a strain of R. japonicum. Acquisition of R68 and R68.45 plasmids by this Rhizobium was equivocal. Transfer of R1822 from Pseudomonas aeruginosa and of pRD1 from Escherichia coli to R. japonicum was unambiguous, because the exconjugants subsequently cotransferred the three R-factor resistance determinants (kanamycin, tetracycline, and penicillin) between genetically marked sublines of strain I-110. Under optimal conditions the transfer of R1822 and pRD1 occurred at frequencies of approximately 10(-3) in plate matings of strains bearing as many as five dissimilar genetic markers. In matings with R1822 on membrane filters, recombinants were formed at incidences as high as 4%.
Production of Higher Alcohols During Indonesian Tapé Ketan Fermentation
Authors: Cronk T. C. , Mattick L. R. , Steinkraus K. H. , Hackler L. R.
Published: January 2020

A study was made of the higher alcohols (fusel oils) produced during the Indonesian tapé ketan fermentation using
Amylomyces rouxii
as the principal mold, alone or in combination with yeasts belonging to genera commonly found in the tapé ketan fermentation (
Endomycopsis, Candida
, and
Hansenula
). Total fusel oils increased with length of fermentation. Fusel oils detected in the product distillate included isobutanol and isoamyl and active amyl alcohols. No
n
-propanol was detected. Isobutanol and isoamyl alcohols were formed in the largest amounts.
A. rouxii
alone produced nearly the same quantity of fusel oils (total production, 275 mg/liter at 192 h) as it did in combination with
Endomycopsis burtonii
(total production, 292 mg/liter at 192 h).
A. rouxii
and
Endomycopsis fibuliger
produced fusel oils totaling 72 mg/liter at 32 h and 558 mg/liter at 192 h.
A. rouxii
in combination with
Candida
yeasts produced somewhat more fusel oils, ranging from 590 to 618 mg/liter at 192 h.
A. rouxii
in combination with
Hansenula
yeasts produced the least fusel oils, totaling 143 to 248 mg/liter at 192 h. During the first 36 h, production of fusel oils was higher at 30 and 35°C than at 25°C. At 48 h fusel oil production was slightly higher at 30°C than at 35°C. Beyond 48 h, production of fusel oils was higher at 25°C.
A. rouxii
in combination with
Hansenula anomala
and
Hansenula subpelliculosa
produced considerable ethyl acetate, ranging from 145 to 199 mg/liter at 36 h and 354 to 369 mg/liter at 192 h.
Measurement of Proteolysis in Natural Waters
Authors: Little Jack E. , Sjogren Robert E. , Carson Gerald R.
Published: January 2020

Microbiological proteolysis in Lake Champlain water was measured in situ and in vitro by the spectrophotometric measurement of the rate of release of soluble color from an insoluble azure dye derivative of hide powder. Water samples sterilized by microfiltration were never proteolytic. In situ proteolysis was found to be very dependent upon water temperature (1 to 23°C). No measurable activity was observed below 4°C. The in vitro proteolysis rate at 20°C was found to be 2.3 times the rate at 15°C and 6 times the rate at 10°C. Water taken from beneath the ice-covered lake throughout the winter and tested in the laboratory at 20°C was found to show an increasing proteolytic potential during the winter months. The highest activity was obtained as the ice broke up in early spring. Microbiological proteolysis in water from Burlington Harbor was often four times that found in center lake water. In most experiments proteolysis was inhibited completely by 2 μg of Cu
2+
and inhibited 67% by 0.75 μg/ml. Proteolysis was markedly stimulated by 20 to 40 μg of Casitone or Casamino Acids per ml. The predominant bacteria growing in the proteolysis flasks were species of
Pseudomonas
and
Flavobacterium.
Pure cultures of
Pseudomonas
required traces of Casitone, Casamino Acids, or yeast extract for proteolysis of hide powder azure, whereas those of
Flavobacterium
did not. The requirement could not be met by a mixture of 21 amino acids and eight vitamins.
Phanerochaete chrysosporium
β-Glucosidases: Induction, Cellular Localization, and Physical Characterization
Authors: Smith Mark H. , Gold Michael H.
Published: January 2020

Phanerochaete chrysosporium
produces intracellular soluble and particulate β-glucosidases and an extracellular β-glucosidase. The extracellular enzyme is induced by cellulose but repressed in the presence of glucose. The molecular weight of this enzyme is 90,000. The

K
m

for
p
-nitrophenyl-β-glucoside is 1.6 × 10
−4
M; the

K
i

for glucose, a competitive inhibitor, is 5.0 × 10
−4
M. The

K
m

for cellobiose is 5.3 × 10
−4
M. The intracellular soluble enzyme is induced by cellobiose; this induction is prevented by cycloheximide. The presence of 300 mM glucose in the medium, however, had no effect on induction. The

K
m

for
p
-nitrophenyl-β-glucoside is 1.1 × 10
−4
M. The molecular weight of this enzyme is ∼410,000. Both enzymes have an optimal temperature of 45°C and an

E
act

of 9.15 kcal (ca. 3.83 × 10
4
J). The pH optima, however, were ∼7.0 and 5.5 for the intracellular and extracellular enzymes, respectively.