bluuebunny/crossref_metadata_2025 huggingface dataset:
Analyzing Territorial and Sectorial Dimensions of Public–Private Partnerships in Science, Technology, and Innovation policies
Authors: Catalá‐Pérez Daniel , de‐Miguel‐Molina María
Published: December 2020

The performance of innovation systems depends, to a great extent, on the degree of public–private collaboration they involve. Thus, innovation policies often aim to enhance this collaboration through public–private partnerships. These partnerships are a multidimensional phenomenon whose success depends on factors related to each of their dimensions. This paper proposes the use of an analytical model that reflects the multidimensional nature of public–private partnerships and analyses to what extent they are applied in a specific innovation system in order to identify the territorial and sectorial factors that act as barriers or drivers to use them. This model aims to help policy makers design appropriate public–private partnerships in each context. The case under review is the Spanish innovation system, given that this system has been suffering from a structural lack of collaboration for several decades, despite the implementation of policies aimed to foster this. Thus, if the model works, it should be able to identify key factors that influence greater or more restricted use of the different PPP formulas.
Low‐intensity resistance exercise with blood flow restriction and arterial stiffness in humans: A systematic review
Authors: Amorim Samuel , Rolnick Nicholas , Schoenfeld Brad J. , Aagaard Per
Published: December 2020

Low‐intensity resistance exercise with blood flow restriction exercise is an emerging type of exercise recognition worldwide. This systematic review evaluated the effects of low‐intensity resistance exercise performed with concurrent blood flow restriction (LIRE‐BFR) on acute and chronic measures of arterial stiffness in humans. A systematic search in six healthcare science databases and reference lists was conducted. Data selected for primary analysis consisted of post‐intervention changes in arterial stiffness markers. This systematic review included randomized and non‐randomized controlled trials of LIRE‐BFR in humans. 156 articles were initially identified, 15 of which met inclusion criteria. Ten studies were excluded because they did not match predefined arterial stiffness markers. Thus, five articles were included in this review: two acute studies (N = 39 individuals, age = 20‐30 years old, 30.8% women and 69.2% men) and three longitudinal studies (N = 51 individuals, age = 24‐86‐years old, 41.2% women and 58.8% men). Acute LIRE‐BFR demonstrated both positive and negative effects on arterial stiffness in healthy young people. In contrast, longitudinal studies reported neutral effects in healthy young and older people. In conclusion, LIRE‐BFR applied to the upper and lower limbs may acutely induce increases in central blood pressure and pulse wave velocity in healthy young people, whereas LIRE‐BFR for the lower limbs may elicit positive effects related to indirect markers of arterial stiffness. Moreover, longitudinal LIRE‐BFR studies showed no changes in arterial stiffness in young and older people. Hence, LIRE‐BFR should be prescribed with a degree of caution to avoid non‐intended responses in arterial stiffness markers in humans.
Wheat 2‐Cys peroxiredoxin plays a dual role in chlorophyll biosynthesis and adaptation to high temperature
Authors: Mishra Divya , Shekhar Shubhendu , Chakraborty Subhra , Chakraborty Niranjan
Published: December 2020

The molecular mechanism of high‐temperature stress (HTS) response, in plants, has so far been investigated using transcriptomics, while the dynamics of HTS‐responsive proteome remain unexplored. We examined the adaptive responses of the resilient wheat cultivar ‘Unnat Halna’ and dissected the HTS‐responsive proteome landscape. This led to the identification of 55 HTS‐responsive proteins (HRPs), which are predominantly involved in metabolism and defense pathways. Interestingly, HRPs included a 2‐cysteine peroxiredoxin (2CP), designated Ta2CP, presumably involved in stress perception and adaptation. Complementation of Ta2CP in yeast and heterologous expression in Arabidopsis demonstrated its role in thermotolerance. Both Ta2CP silencing and overexpression inferred the involvement of Ta2CP in plant growth and chlorophyll biosynthesis. We demonstrated that Ta2CP interacts with protochlorophyllide reductase b, TaPORB. Reduced TaPORB expression was found in Ta2cp‐silenced plants, while upregulation was observed in Ta2CP‐overexpressed plants. Furthermore, the downregulation of Ta2CP in Taporb‐silenced plants and reduction of protochlorophyllide in Ta2cp‐silenced plants suggested the key role of Ta2CP in chlorophyll metabolism. Additionally, the transcript levels of AGPase1 and starch were increased in Ta2cp‐silenced plants. More significantly, HTS‐treated Ta2cp‐silenced plants showed adaptive responses despite increased reactive oxygen species and peroxide concentrations, which might help in rapid induction of high‐temperature acclimation.
Lagrangian Analysis of Unsteady Partial Cavitating Flow Around a Three-Dimensional Hydrofoil
Authors: Yin Tingyun , Pavesi Giorgio , Pei Ji , Yuan Shouqi , Cavazzini Giovanna , Ardizzon Guido
Published: December 2020

This study employs an incompressible homogeneous flow framework with a transport-equation-based cavitation model and shear stress transport turbulence model to successfully reproduce the unsteady cavitating flow around a three-dimensional hydrofoil. Cavity growth, development, and break-off during the periodic shedding process are adequately reproduced and match experimental observations. The predicted shedding frequency is very close to the experimental value of 23 ms. By monitoring the motions of the seeding trackers, growth-up of attached cavity and dynamic evolution of U-type cavity are clearly displayed, which indicating the trackers could serve as an effective tool to visualize the cavitating field. Repelling Lagrangian coherent structure (RLCS) is so complex that abundant flow patterns are highlighted, reflecting the intricacy of cavity development. The formation of cloud cavities is clearly characterized by the attracting Lagrangian coherent structure (ALCS), where bumbling wave wrapping the whole shedding cavities indicates the rotating transform of cavities, and stretching of the wave eyes shows the distortion of vortices. Generation of the re-entrant jet is considered to be not only associated with the adverse pressure gradient due to the positive attack angle but also the contribution of cloud cavitating flow, based on the observation of a buffer zone between the attached and cloud cavities.
Design optimization of sub-5 nm node nanosheet field effect transistors to minimize self-heating effects
Authors: Ding Fei , Wong Hiu-Yung , Liu Tsu-Jae King
Published: December 2020

In this work, self-heating effects (SHE) in nanometer-scale metal-oxide-semiconductor field-effect transistor structures—namely, FinFETs (FFs), nanosheet gate-all-around FETs (NSFs), and nanowire gate-all-around FETs (GAAFs)—are investigated via three-dimensional device electrothermal simulations using technology computer-aided design software tools. Initially, transistor design parameter values are set so that their on-state currents are similar for the same operating voltage (VDD). It is found that NSFs and GAAFs are more susceptible to SHE and that p-channel transistors have higher peak internal temperatures than do their n-channel counterparts due to the poor thermal conductivity of the silicon-germanium used as the p-type source/drain material. Subsequently, the on-state currents of FFs, NSFs, and GAAFs are compared under the constraint of identical peak internal temperature, which is required to ensure long-term reliability, revealing that NSFs and GAAFs offer no performance advantage over FFs under this constraint. Design optimization of p-channel NSFs for minimal SHE is subsequently investigated. It is found that with such optimization, NSFs operating at lower VDD (for similar SHE) can achieve similar on-state current as FFs.
Impact of Two Preservice Teachers’ Value Orientations on Their Interpretation and Delivery of the Skill Themes Approach
Authors: May Leah K. , Curtner-Smith Matthew D.
Published: December 2020

Purpose: To determine the impact of two preservice teachers’ value orientations on their interpretation and delivery of the skill themes approach. Method: The short form of the value orientations inventory and five qualitative techniques were used to collect data. Participants’ value orientations inventory profiles were illustrated graphically. Interpretive data were analyzed using analytic induction and constant comparison. Findings: Results from the short form of the value orientations inventory indicated that Meagan prioritized social responsibility, learning process, and disciplinary mastery, while Jared favored social responsibility, self-actualization, and ecological integration. Qualitative data largely supported these value orientation profiles and indicated that the preservice teachers’ approaches to teaching skill themes differed and were influenced by their pedagogical beliefs. Moreover, qualitative data illustrated how Meagan’s and Jared’s value orientations and interpretations of the skill themes approach had changed and developed. Conclusions: These findings emphasize the importance of preservice teachers engaging in philosophical reflection on the connections between their beliefs and their interpretations of curriculum models.
Critical Role of MetR/MetB/MetC/MetX in Cysteine and Methionine Metabolism, Fungal Development, and Virulence of Alternaria alternata
Authors: Gai Yunpeng , Li Lei , Ma Haijie , Riely Brendan K. , Liu Bing , Li Hongye
Published: December 2020

The transcription factor METR, regulating methionine metabolism, is essential for ROS tolerance and virulence in many phytopathogenic fungi. However, the underlying regulatory mechanism of METR involved in this process is still unclear.
The Aerogenic Response of
Escherichia coli
and Strains of
Aerobacter
in EC Broth and Selected Sugar Broths at Elevated Temperatures
Authors: Fishbein Morris
Published: December 2020

Gas formation by 116 strains of
Escherichia coli
and 104 strains of
Aerobacter
was determined in a specially constructed and accurately controlled water bath employing EC, lactose, maltose, sucrose, glucose, levulose, and galactose broths at temperatures ranging from 44.5 to 46.5 C.

Greatest gas activity occurred in EC broth. In the range 44.9 to 45.5 C over 92% of the
E. coli
cultures formed gas, but the
Aerobacter
strains dropped from 68 to 2%. A natural point of separation of the two groups occurred at 45.5 C.

Inhibition of the gas-forming mechanism rather than death is the universal response of the
Escherichia
organisms to these temperatures. The inhibition increases with rising temperatures and is readily reversible. At 46.5 C, 64.5% of all the
Escherichia
cultures were inhibited and 69.1% of all the cultures were actually viable.

In EC broth it was found that as a group atypical
E. coli
(-+--) were the most resistant gas-positive types. Least resistant in EC broth was a group of known typical fecal isolates of
E. coli
(++--). Of intermediate resistance between the two groups was the large body of typical
E. coli
(++--) organisms.

Certain individual strains of
E. coli
excelled in the production of gas in the variety of sugar broths tested at elevated temperatures. The
Aerobacter
strains did not exhibit this property.

Finally it is suggested that elevated temperature incubation studies of this type be conducted in critically controlled water baths with an ascertained accuracy in the vicinity of 45.5 ± 0.1 C under full load.
A Transparent Solid Medium for Growth Enhancement of
Pasteurella tularensis
Authors: Gaspar Andrew J. , Faber John E.
Published: December 2020

A transparent plating medium capable of initiating early and rapid growth of the SCHU S4 strain of
Pasteurella tularensis
is described. On this medium, colonies 1 mm in diameter were obtained following 29 hr of incubation at high humidity. To obtain this growth enhancement, blood factors were provided in the form of a peptic digest of hemoglobin and a saline wash of red blood cells (rabbit). In the basal medium, the presence of both 0.5%
l
-cysteine-HCl, and sodium thioglycolate, was required to achieve this growth response.
Destruction of Enteric Bacteria in Liquid Egg with β-Propiolactone
Authors: Bruch Carl W. , Koesterer Martin G.
Published: December 2020

Liquid whole egg or egg white, inoculated with
Escherichia coli
1485,
Salmonella senftenberg
ATCC 8400, or
Salmonella typhimurium
84-I, was treated with concentrations of β-propiolactone ranging from 0.05 to 0.3%. Egg white containing 1 × 10
3
to 1 × 10
6
cells of
E. coli
1485 per ml was sterilized in 1 hr at 27 C by lactone concentrations of 0.2 and 0.3%. Egg white containing 1 × 10
5
cells of
S. senftenberg
ATCC 8400 per ml was sterilized in 12 hr at 10 C by 0.1% lactone and in 2 to 3 hr by 0.3% lactone at the same temperature.

Liquid whole egg inoculated with 1 × 10
5
cells of either species of
Salmonella
was sterilized in 4 to 5 hr at 10 C with 0.2% lactone or in 2 to 3 hr by 0.3% lactone at this temperature. A mild heat treatment of either 15 min at 37 C or 1 min at 55 C markedly shortened the exposure times required for sterilization by β-propiolactone at 10 C.

After disinfection was complete, the lactone-treated liquid whole egg was reinoculated with low cell numbers of either species of
Salmonella
to determine the presence of residual lactone or toxic products. Liquid whole egg treated with 0.2% lactone would support the growth of salmonellae after 13 to 14 hr at 10 C. A heat treatment of 45 min at 37 C or 10 min at 55 C immediately after addition of 0.2% lactone allowed growth of the salmonellae in the lactone-treated liquid whole egg. No evidence of residual toxicity from the lactone treatment was found.

The amount of lactone needed to prevent the outgrowth of low cell numbers of either strain of
Salmonella
in liquid whole egg was quantitated. Liquid whole egg containing 0.06 to 0.07% lactone would not support salmonellae growth from inocula of 1 to 10 cells per ml of egg. Lactone concentrations above 0.08% prevented outgrowth of salmonellae inocula of 10 to 200 cells per ml of liquid whole egg.
Microbiological Production of Carotenoids
Authors: Ciegler Alex , Nelson George E. N. , Hall Harlow H.
Published: December 2020

Synthesis of β-carotene by mated strains of
Blakeslea trispora
in shaken-flask culture was considerably enhanced by adding either 5% kerosene after 2 days of fermentation or acid-refined kerosene at the start of fermentation to a grain-based medium that also contained a natural lipid, nonionic detergent, and β-ionone; average yields of 17,500 μg per g of dry fermentation solids (86,000 μg per 100 ml of medium) were attained when refined kerosene was used. Almost all of the carotene was retained within the mycelium. Peak yields were achieved in 5 days.
Tetanus Toxin Production in the Absence of Protein
Authors: Latham William C. , Bent Donald F. , Levine Leo
Published: December 2020

A modification of the Mueller medium for tetanus toxin production is presented, on which an adapted strain produces high yields of toxin (70 to 90 flocculating units per ml) in the absence of animal protein extracts.

The range of iron concentration in the medium was established within which the toxigenic activity of the culture can be made to vary, and the mathematical nature of the variation is presented. Darkening of cultures during incubation indicates departure from optimal conditions. Heat input to the medium during autoclaving, originally undertaken solely for purposes of sterilization, is an important physicochemical factor in the toxigenicity of the culture.
Rearing of Germfree and Monocontaminated Chicks in Rigid Plastic Isolators
Authors: Phillips A. W. , Newcomb H. R. , Lachapelle R. , Balish E.
Published: December 2020

A Plexiglas isolator for rearing germfree vertebrates is described. Plastic components were precut and finished by a Plexiglas supplier. This equipment is relatively inexpensive; moreover, neither special facilities nor skills are required in their construction. Advantages of this type of isolator are: readily dismantled for cleaning, durable, excellent visibility of the interior, and minimal maintenance. In 30 separate groups of animals, 27 of these yielded germfree chicks. Many of these chicks were reared germfree for 4 weeks; and several were maintained for about 2 months, without microbial contamination. Pure cultures of
Candida albicans, Streptococcus faecalis
, and
Clostridium perfringens
were established as monocontaminations in the intestinal tracts of chickens. In contrast,
Alcaligenes faecalis
ATCC 9220 failed to grow in the gut of chicks, following peroral administration of this organism. All chicks described were employed on other experiments, and were killed for various assays at times specified.
The Development of a Nonmicrobial Off-Condition in Fresh Meat
Authors: Shank J. L. , Silliker J. H. , Goeser P. A.
Published: December 2020

It has long been accepted, prima facie, that bacteria are the sole cause of a “sour” condition which is occasionally but persistently found in some fresh beef rounds. Evidence is presented which indicates that this condition often bears no relation to the bacteriology of the muscle involved. It was observed that sour rounds contain elevated quantities of volatile fatty acids. On the basis of experiments in which this condition was artificially induced in vivo, it is suggested that a metabolic block of meat enzymes could account for this build-up of short chain acids.
Biosynthesis of Cephalosporin C
Authors: Demain Arnold L. , Newkirk Joanne F.
Published: December 2020

The superiority of
d
-methionine over
l
-methionine for stimulation of cephalosporin C synthesis in a crude medium was confirmed. The optimal level of
dl
-methionine was 0.5%. Methionine stimulates growth slightly but this is not thought to be the cause of the marked stimulation of antibiotic synthesis. Of a large number of sulfur compounds tested, only
dl
-methionine-
dl
-sulfoxide and S-methyl-
l
-cysteine showed considerable methionine-replacing activity. Lysine and α-aminoadipic acid were inactive.
Paraformaldehyde-Resistant Starch-Fermenting Bacteria in “Starch-Base” Drilling Mud
Authors: Myers G. E.
Published: December 2020

Starch-fermenting bacteria were found in each of 12 samples of nonfermenting starch-base drilling mud examined. Of the 12 samples, 3 contained very active starch-fermenting gram-positive spore-bearing bacilli closely resembling
Bacillus subtilis
. Similar active starch-fermenting bacteria were found in fermenting starch-base drilling mud and in corn starch and slough water used to prepare such mud. The active starch-fermenting microorganisms completely hydrolyzed 1% (w/v) corn starch within 24 hr at 37.5 C. The active starch-fermenting bacteria isolated from fermenting drilling mud were capable of surviving 12 hr of continuous exposure to 0.1% (w/w) paraformaldehyde or 1 hr of continuous exposure to 0.5% (w/w) paraformaldehyde, with no diminution in starch-fermenting ability. The same organisms fermented starch after 3 hr of continuous exposure to 0.5% (w/w) paraformaldehyde, but not after 4 hr of exposure. The phenomenon of rapid disappearance of paraformaldehyde from fermenting drilling mud was observed in the laboratory using a modified sodium sulfite test. Paraformaldehyde, initially present in a concentration of 0.192 lb per barrel of mud, completely disappeared in 9 hr at 22 to 23 C. A significant decrease in paraformaldehyde concentration was detected 0.5 hr after preparation of the mud. It is suggested that the presence of relatively high concentrations of ammonia and chloride in the mud may facilitate the disappearance of paraformaldehyde. The failure of 0.1% (w/w) paraformaldehyde to inhibit the strong starch-fermenting microorganisms isolated from fermenting drilling mud, and the rapid disappearance of paraformaldehyde from the mud, explains the fermentation of starch which occurred in this mud, despite the addition of paraformaldehyde.
Attempts to Freeze Some Bacteriophages to Ultralow Temperatures
Authors: Clark William A. , Horneland Wanda , Klein A. G.
Published: December 2020

A variety of bacteriophages specific for different hosts, including
Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Serratia marcescens, Shigella dysenteriae, Staphylococcus aureus
, and
Vibrio comma
, were frozen at a controlled rate to liquid nitrogen temperatures, and then quick-thawed. Glycerol (10%) was used as a protective additive. Quantitative determinations showed from 10% to virtually 100% recovery in the various cases. Host specificity, plaque morphology, and, in one case, rate of inactivation of phage by homologous antiserum remained unchanged.
Fate of Staphylococci and Enteric Microorganisms Introduced into Slurry of Frozen Pot Pies
Authors: Dack G. M. , Lippitz G.
Published: December 2020

A slurry was prepared from six frozen pot pies diluted 1:5 with distilled water, two chicken, two turkey, and two beef pies of different brands. This slurry formed a reference sample and was placed in sterilized jars, frozen, and used as needed throughout the experiments. A second slurry was prepared in a similar manner from a frozen beef pot pie and a chicken pot pie, and was used as a control in only one experiment. The total count of microorganisms and the number of coliforms,
Escherichia coli
, salmonellae, and coagulase-positive staphylococci per gram were determined. Samples of slurry were inoculated in decimal dilutions with one or more of the following:
Salmonella typhimurium, E. coli
, and a strain of staphylococcus that causes food poisoning. The natural flora was found to exert an inhibitory effect upon the growth of the added microorganisms after incubation at 35 C for 18 hr. The inhibitory effect on growth was in part due to pH. The predominating organism isolated from the natural flora after incubation was a lactobacillus, which, when added in mixture with the test organisms in sterilized slurry, did not exert the profound inhibitory effect observed in the case of the natural flora. Some factors which may be concerned with the inhibition were investigated.
Quantitative Studies of Total Lipids of Pathogenic Fungi
Authors: Al-Doory Yousef , Larsh Howard W.
Published: December 2020

Ten species of dermatophytes and four of the systemic fungi were assayed for total lipids, acetone-soluble fraction, and phospholipid content in different types of cultures. The yeast phase of each of the systemic fungi grown on solid medium exhibited a higher total lipid content than did the mycelial growth in liquid medium, either shake or still. Shake cultures, in all the fungi tested, produced the least lipids. The yeasts were consistently higher also in the acetone-soluble fraction.
Histoplasma duboisii
in the yeast phase and
Microsporum gypseum
produced the greatest amount of phospholipid, and
Blastomyces dermatitidis
in the yeast phase and
M. canis
produced the largest acetone-soluble fraction among the systemic fungi and dermatophytes, respectively.
Survey of Selected Filamentous Fungi for Voges-Proskauer Reactions
Authors: Fields M. L.
Published: December 2020

Of 16 filamentous fungi surveyed for Voges-Proskauer reactants, 81.2% were found to be positive. The total group fell into three classes: those producing considerable acetylmethylcarbinol (AMC), those producing a small amount, and those producing no AMC.
Oidium lactis
had a highly significant effect upon lowering the amount of Voges-Proskauer reactants produced by
Rhizopus nigricans
.
Microbiological Transformation of Terpenes
Authors: Prema B. R. , Bhattacharyya P. K.
Published: December 2020

The action of
Aspergillus niger
on mono- and sesqui-terpenic hydrocarbons, such as carane, 3-carene, α-santalene, and humulene was studied in shake cultures. Carane, Δ3-carene, and humulene proved to be rather resistant to oxygenation by the experimental strain of
A. niger
. Carene yielded a hydroxyketone, C
10
H
14
O
2
, in poor yields after prolonged fermentation. The sesqui-terpene hydrocarbon, α-santalene, was degraded mainly to an acid,
tere
-santalic acid. Two hydroxylated products were also obtained from α-santalene, viz., tere-santalol and an alcohol, C
15
H
24
O.
Incidence of
Clostridium perfringens
in American Foods
Authors: Strong Dorothy H. , Canada James C. , Griffiths Bertie B.
Published: December 2020

Food samples were examined for the presence of
Clostridium perfringens
. A medium described by Mossel and later modified by Angelotti et al. was used for the detection and enumeration of
C. perfringens
. The incidence of
C. perfringens
observed in the foods examined was 6.1%.
C. perfringens
was recovered from 2.7% of the commercially prepared frozen foods, 3.8% of fruits and vegetables, 5.0% of spices, 1.8% of home-prepared foods, and 16.4% of raw meat, poultry, and fish.
Effect of Heat on Spores of Rough and Smooth Variants of
Bacillus stearothermophilus
Authors: Fields M. L.
Published: December 2020

Spores of variants of
Bacillus stearothermophilus
were subjected to activating and lethal temperatures. Spore suspensions which were incubated longer contained a higher percentage of spores of the rough variant. The effect of sublethal heat on spore suspensions containing mixed variants (rough and smooth) was difficult to measure at sublethal temperatures (110 C), since the rough variant was not as heat-resistant. While the rough variant was activated in a shorter time, the smooth variant was not activated; when the smooth variant was activated, the rough was killed. A higher percentage of the smooth variant was forced into dormancy after being held at 50 C for 30 hr than the rough variant. When mixed populations were subjected to a lethal temperature (120 C), the curves only reflected the smooth variant. Since the curves which represented the smooth variant or mixtures containing the smooth variant were not linear, this was thought to be due to activation overbalancing the lethal effect. This research emphasized the importance of variants in explaining differences in spore resistance among spore suspensions of the same strain.
Enzyme Production by Species of
Cephalosporium
Authors: Pisano M. A. , Oleniacz W. S. , Mason R. T. , Fleischman A. I. , Vaccaro S. E. , Catalano G. R.
Published: December 2020

The culture filtrates of ten species of
Cephalosporium
, which had been grown under conditions of submerged culture, were tested for enzymatic activity against each of seven substrates. The latter included casein, gelatin, milk, hemoglobin, human plasma clots, starch, and
N
-acetyl-β-D-glucosaminide. All organisms tested were active, but to varying degrees. The most pronounced activities were obtained against the proteinaceous substrates. Two unidentified species of
Cephalosporium
exhibited the highest over-all activities, but no one organism predominated for all enzymatic functions. The ability of a filtrate to degrade a specific substrate was not always correlated with its ability to attack other substrates. The fibrinolytic properties of three of the cephalosporia were of particular interest. α-Amylase activity was not significant. The results obtained suggest the possible use of selected species of
Cephalosporium
as sources of a variety of microbial enzymes.
Enhancement of β-Carotene Synthesis by Citrus Products
Authors: Ciegler Alex , Nelson George E. N. , Hall Harlow H.
Published: December 2020

β-Ionone, a stimulatory compound in the microbiological production of β-carotene by mated cultures of
Blakeslea trispora
, could be replaced with low-cost agricultural by-products (citrus oils, citrus pulp, or citrus molasses) with as good or better carotene yields. Peak yields (81 to 129 mg of carotene per g of dry solids) were achieved in 5 days. The various citrus products tested did not change the pigments produced; all
trans
-β-carotene remained the pre-dominant pigment. The acid-hydrolyzed soybean meal and corn used in previous production media could be replaced with unhydrolyzed cottonseed embryo meal and corn in a medium that also contained a natural lipid, deodorized kerosene, nonionic detergent, and a precursor.
Multicomponent Substrate Utilization by Natural Populations and a Pure Culture of
Escherichia coli
Authors: Gaudy A. F. , Gaudy Elizabeth T. , Komolrit K.
Published: December 2020

A heterogeneous population, typical of activated sludge, and a prototrophic strain of
Escherichia coli
were used to test for sequential substrate removal in a glucose-sorbitol medium. Each culture was preacclimated to sorbitol and was studied in the two-component medium under growing and nonproliferating conditions. In all four systems, glucose blocked sorbitol removal. Since large initial inocula were used, the suppression of sorbitol metabolism could not be totally due to repression of enzyme synthesis. The results indicate that glucose may affect the functioning of an existing enzyme system in addition to its established effect on enzyme synthesis. From an applied standpoint, the results indicate that an activated sludge may be completely and immediately prevented from eliminating a waste constituent to which it is acclimated.
Preservation of Bacteria by Circulating-Gas Freeze Drying
Authors: Wagman Jack , Weneck Edward J.
Published: December 2020

Water-washed
Serratia marcescens
and
Escherichia coli
were freeze dried in a circulating-gas system at atmospheric pressure. This convective procedure resulted in a substantially higher survival of organisms than could be obtained by the vacuum method of freeze drying. There was little or no decrease in cell viability during convective drying when the residual moisture content was 15% or higher. Below this level, survival declined with decreasing moisture content. A detailed comparison of the convective and vacuum methods indicated that the advantage gained by freeze drying bacteria in air accrues in the early period of sublimation, at which time cells were found to be sensitive to vacuum drying but insensitive to air drying. An explanation for this difference is proposed, based upon the kinetics of water removal in the two processes. In brief, it is suggested that the convective method permits samples to be dried more uniformly; and regional over-drying, which may be deleterious even if transient, is thus avoided in achieving the optimal level of moisture.
Injury and Death of
Streptococcus lactis
due to Freezing and Frozen Storage
Authors: Moss C. Wayne , Speck Marvin L.
Published: December 2020

Cells of
Streptococcus lactis
were harvested in the early stationary phase, washed, and resuspended in either skim milk (10% nonfat milk) or buffered distilled water (0.0003
m
dipotassium phosphate, pH 7.2). Samples of each suspension were frozen and stored at -20 C for intervals up to 28 days. Colony counts of the frozen culture were made using lactic agar and a “restricted” lactic agar medium (Tryptone reduced to 0.5%) to determine injury and death. Death was determined by the difference in plate counts on lactic agar before and after freezing. Injured cells were determined by the difference in plate counts on the two plating media. Greatest injury of the cells occurred during early stages of frozen storage and decreased with time, and death continuously increased. Injury and death were more pronounced when cells were frozen in water than when frozen in 10% nonfat milk solids. Certain cultures survived better when frozen rapidly, whereas with others survival was greater when freezing was slow. Successive freezing, thawing, and propagation of the culture gradually eliminated cells which showed injury by freezing.
Bacterial Utilization of Dodecyl Sulfate and Dodecyl Benzene Sulfonate
Authors: Payne W. J. , Feisal V. E.
Published: December 2020

Two unknown bacterial isolants (C12 and C12B) were obtained from enriched soils and cultured on media containing detergent compounds as sole sources of carbon. Either isolant destroyed the foaming capacity of cultures containing dodecyl sulfate; but C12B, which could grow on dodecyl benzene sulfonate (DBS) whereas C12 could not, did not destroy the foaming capacity of this surfactant. The source of DBS available in quantity was a mixture of isomers derived from kerosene, and the bacteria utilized only one-fifth to one-fourth of this material during growth. Both isolants grew on short- or long-chained organic acids, and resting cells of both rapidly oxidized several long-chain acids and alcohols. Three of five phenyl-placement isomers of DBS (with the phenyl group at carbon 2, 3, or 6 on the alkyl chains) were excellent substrates for growth of C12B, but isomers with phenyl placement at carbon 4 or 5 were toxic and killed the bacteria.
Resistance of Free-Living Nematodes to Staphylococcal Enterotoxin
Authors: Chang Shih L. , Hall Herbert E.
Published: December 2020

The usefulness of free-living nematodes for assaying staphylococcal enterotoxin was evaluated with a 98% pure enterotoxin B on five different nematodes. Included in the evaluation was an enterotoxin B in a crude culture filtrate. The filtrate of a culture of nonenterotoxigenic strains of
Staphylococcus aureus
, the uninoculated respective broth media, and distilled water were used as controls. The purified enterotoxin was found to exert no toxic effects at dosages ranging from 10 to 1,000 μg/ml for as long as 24 hr. Utilization of the toxin-protein by these nematodes was evidenced by their propagation after exposure times longer than 24 hr. The crude filtrate, containing 28 μg of enterotoxin per ml, was detrimental to nematodes to the same degree as the nontoxic filtrate and the uninoculated broths, in that they all caused irritation to external genitalia, motility changes, and death after comparable exposure times. This is in agreement with earlier observations that standard bacteriological fluid media, or broths containing over 1% protein hydrolysate or 1 to 2% salts, exert toxic effects on free-living nematodes.
Production of Pectolytic Enzymes by
Rhizopus stolonifer
Sporangiospores After “Lethal” Gamma Irradiation
Authors: Sommer N. F. , Creasy Min T. , Maxie E. C. , Romani R. J.
Published: December 2020

Irradiated sporangiospores of
Rhizopus stolonifer
excreted pectolytic enzymes, which hydrolyzed pectin and macerated potato tuber discs, into the suspending medium. Pectin glycosidase, but not pectin methylesterase, activity developed regardless of the amount of radiation the spores had received, unless the dose exceeded about 1 megarad. The ability to produce pectolytic enzymes was found to be more radiation-resistant than the potential for colony formation or the ability to germinate. Spores made incapable, through irradiation, of forming colonies continued to produce pectolytic enzymes after a 6-day period following irradiation treatment.
Some Observations on Bacterial Thermal Death Time Curves
Authors: Licciardello J. J. , Nickerson J. T. R.
Published: December 2020

Thermal death rate data were obtained for spores of
Clostridium sporogenes
P.A. 3679 and
Bacillus subtilis
var.
niger
, and for cells of
Salmonella senftenberg
775W. The survival curves for P.A. 3679 were approximately linear, but for
B. subtilis
var.
niger
or
S. senftenberg
775W they were sigmoidal. Decimal reduction times were derived from the regression slopes of the apparent linear portion of the survival curves, and from these a phantom thermal death time (TDT) curve was constructed. In general, the phantom TDT curves were linear for
B. subtilis
var.
niger
and
S. senftenberg
775W and nonlinear for P.A. 3679.
Staphylococci in Competition
Authors: Peterson A. C. , Black J. J. , Gunderson M. F.
Published: December 2020

Foods containing large amounts of carbohydrate have frequently been involved in staphylococcal food poisoning. Custard has been considered to be a highly favorable culture medium for staphylococci; however, it may be a selective medium rather than an ideal one. The influence of dextrose, lactose, and sucrose in varying amounts from 0.25 to 18%, and of starch, on the growth of staphylococci in mixed populations with saprophytes was determined. The inhibitory effect of the sugars was much greater on the saprophyte population than on the staphylococci. Of the three sugars, sucrose was most inhibitory to the saprophytes. It greatly decreased their lag periods as the concentration of sugar increased. Dextrose was the least inhibitory; in fact, 0.5% dextrose gave considerable stimulus to saprophyte growth. This sharply repressed staphylococcal growth. Lactose occupied an intermediate position. Rapid onset of the death phase of the staphylococci was observed in all increased sugar concentrations and seemed to be a pH effect rather than a result of competition. Sucrose exerted an inhibitory effect on the growth of saprophytes at and above room temperature. In the presence of 2.5% corn starch, staphylococcal growth in mixed cultures was slightly inhibited, while the death phase was sharply accelerated. Thus, carbohydrates exert their influence on staphylococcal growth in mixed cultures through their effect on the saprophytes by decreasing or increasing competition.
Use of Calcium Dipicolinate for Enumeration of Total Viable Endospore Populations Without Heat Activation
Authors: Busta F. F. , Ordal Z. John
Published: December 2020

A method, based on germination with 50 m
m
CaCl
2
and 40 m
m
sodium dipicolinate (Na
2
DPA), was developed for the determination of total viable counts of bacterial spores requiring heat activation. Incorporation of these germinating agents into Tryptone Glucose Extract Agar permitted plate-count enumeration of essentially 100% of
Bacillus subtilis
strain 5230 spores without a heat treatment. Other spore suspensions were surveyed for their response to CaCl
2
and Na
2
DPA, and for the subsequent removal of the heat-activation requirement for enumeration of maximal populations.
Influence of Inorganic Phosphorus on Oxytetracycline Formation by
Streptomyces rimosus
Authors: Zygmunt Walter A.
Published: December 2020

Production of oxytetracycline by
Streptomyces rimosus
in several chemically defined media containing graded concentrations of inorganic phosphorus was studied in shake flasks. Although high levels of inorganic phosphate have been reported to inhibit oxytetracycline formation, this study indicated that composition of the medium is an important factor in determining whether antibiotic production will be stimulated or inhibited by specific concentrations of inorganic phosphate.
Isolation of Salmonellae From Food Samples
Authors: Silliker J. H. , Deibel R. H. , Fagan P. T.
Published: December 2020

The recovery of salmonellae from egg products was studied, by use of three different enrichment procedures: (i) selenite broth, (ii) selenite broth containing 10% sterile feces, and (iii) the lactose pre-enrichment procedure. Brilliant Green Agar was used throughout as the recovery medium. Although the lactose pre-enrichment methodology promoted
Salmonella
recovery from samples containing small numbers of dormant organisms, the efficiency of this enrichment method is adversely affected by unfavorable coliform-
Salmonella
ratios. Under such conditions, early subculture of lactose broth into selenite broth is indicated. Selenite broth containing 10% sterile feces was more efficient than the lactose pre-enrichment methodology in promoting the growth of “dormant” salmonellae. Albumen adversely affected recovery of salmonellae from selenite broth, whereas whole egg and egg yolk enhanced
Salmonella
recovery from this medium. The selenite-feces medium presents a solution to the major problems encountered in the detection of salmonellae in egg products and offers an approach to a single medium in which food-borne salmonellae will manifest themselves with a minimum of laboratory manipulation.
Use of Chemical Oxygen Demand Values of Bacterial Cells in Waste-Water Purification
Authors: Gaudy A. F. , Bhatla M. N. , Gaudy E. T.
Published: December 2020

Four methods for determining substrate recoveries in studies concerned with the partition of substrate between sludge synthesis and respiration were investigated. An energy balance comparing chemical oxygen demand (COD) removed with the summation of oxygen uptake and the COD of the cells produced yielded average recoveries closer to 100% than any of the other three methods tested. The standard COD test was shown to yield highly reproducible values when used to determine the COD of activated sludge. Although the protein and carbohydrate content of the cells varied with cell age, a concomitant variation in cell COD was not noted.
Rifamycin
Authors: Thiemann J. E. , Hengeller C. , Virgilio A. , Buelli O. , Licciardello G.
Published: December 2020

Five actinophages highly specific for
Streptomyces mediterranei
were isolated from lysed broth cultures. Studies were performed on the effect of plating conditions on plaque formation. The development of phage-resistant strains of
S. mediterranei
not only eliminated the phage but also significantly increased rifamycin yields. The phage-resistant cultures proved to be more unstable than the original sensitive strain. Maintenance of the cultures as frozen vegetative mycelium assured culture stability and reproducibility of the results. Strict aseptic precautions throughout the laboratories and fermentation areas did not eliminate the danger of phage infection; effective control was obtained only with the introduction of resistant strains.
S. mediterranei
phages proved to be highly specific for calcium as an adsorption cofactor; addition of calcium-sequestering agents to sensitive mycelium completely prevented its lysis by the phage. The resistant strains developed were capable of adsorbing the phage and of releasing it without multiplication upon aging of the mycelium. No marked morphological, cultural, or biochemical differences were found among the various phage-resistant strains.
Utilization of a Stable Isotope of Oxygen by
Pseudomonas fluorescens
Authors: Arthur Robert M.
Published: December 2020

Oxygen utilization is defined in this investigation as the terminal use of oxygen in respiration, i.e., the formation of water. A culture of
Pseudomonas fluorescens
was allowed to respire in an atmosphere of O
18
. The production of H
2
O
18
was measured during two test runs of 124 and 232 min each. During the first run, 0.505 mmole of H
2
O
18
was produced. The second run produced 0.460 mmole of H
2
O
18
. H
2
O
18
production took place throughout the course of each of the runs.
Assay of Vitamins and Amino Acids With Cultured Tissue Cells and Antimetabolites
Authors: Savchuck W. B. , Merriman M. E. , Lockhart W. L.
Published: December 2020

A survey of growth responses of tissue-culture cells to vitamins and amino acids was undertaken to explore the potentialities of tissue culture in the assay of growth factors. An antagonist of the nutrient was included in each test system to improve its sensitivity. Addition of an antimetabolite was advantageous in the thiamine and phenylalanine assays. Tissue-culture assays of tryptophan and of phenylalanine supplemented with β-2-thienylalanine compared favorably with microbial assays, and may serve as confirmatory or supplementary test systems. The sensitivity of cultured tissue cells to minute amounts of a variety of physiologically active substances suggests their employment in hormone and toxic compound assays.
Production of Hydrogen Sulfide by
Streptomyces odorifer
Authors: Collins R. P. , Gaines H. D.
Published: December 2020

By use of various trapping systems, as well as lead acetate papers,
Streptomyces odorifer
was shown to produce hydrogen sulfide. Other sulfur-containing compounds may be produced by
S. odorifer
, but the amounts obtained were too small for detailed analysis. It was suggested that hydrogen sulfide might be a part of the earthy-odor complex produced by
S. odorifer
.
Modifications of a Device for Maintenance of the Rumen Microbial Population in Continuous Culture
Authors: Slyter L. L. , Nelson W. O. , Wolin M. J.
Published: December 2020

An improved and simplified apparatus for maintaining the rumen microbial population in continuous culture was constructed. All components were easily obtained from commercial sources or were simple to construct. Mechanical difficulties were minimal, and little attention was needed on the part of the operator. The deoxyribonucleic acid (DNA) content of the cultures (100 to 150 μg/ml) varied little during 7 days of continuous culture, and protozoal concentration decreased from 10
5
per ml to a steady-state level of 2 × 10
3
per ml in 4 days. Volatile fatty acid and methane production followed the normal in vivo pattern for 7 days of continuous culture. DNA, protozoal concentrations, and fermentation patterns did not significantly change between 4 and 21 days of continuous culture.
Kinetics of Death of Bacterial Spores at Elevated Temperatures
Authors: Wang Daniel I-C. , Scharer Jeno , Humphrey Arthur E.
Published: December 2020

The kinetics of death of
Bacillus stearothermophilus
spores (FS 7954) suspended in phosphate buffer (pH 7) were studied over a temperature range of 127.2 to 143.8 C and exposure times of 0.203 to 4.150 sec. These short exposure were achieved by use of a tubular flow reactor in which a suspension of spores was injected into a hot flowing stream at the entrance of the reactor. Thermal equilibria of the suspension with the hot stream was achieved within 0.0006 sec. After flow through a fixed length of reactor, the stream containing the spores was cooled by flash vaporization and then assayed for viable count. The death rate data were fitted by a logarithmic expression. However, logarithmic death rate was only approximated in the tail or high-kill regions of exposure. Death rate constants obtained from this portion of the data were found to correlate by Arrhenius as well as Absolute Reaction Rate Theory relationships. Thermal-death time curves were found to correlate the data rather poorly. The activation energy and frequency constant for an Arrhenius relationship fit of the data were found to be 83.6 kcal/gmole and 10
47.2
min
-1
, respectively. The standard enthalpy and entropy changes for an Absolute Reaction Rate Theory relationship fit of the data were found to be 84.4 kcal/gmole and 157 cal/gmole-K, respectively.
Delayed Appearance of Lactobacilli in the Intestines of Chicks Reared in a “New” Environment
Authors: Bare L. N. , Wiseman R. F.
Published: December 2020

Male chicks (1 day old; Vantress × Arbor Acre) were fed a basal folic acid-deficient diet, a 5% uric acid-containing diet with and without 5 mg/lb (453.5 g) of bacitracin and 20 mg/lb of sodium penicillin G, the basal diet supplemented with only the antibiotics, and the basal diet plus 500 μg/lb of folic acid. The chicks were reared in a room which had not been used previously for housing chickens (“new” environment). Bacteriological analyses of the contents of the small intestine revealed a decrease in numbers of streptococci and “anaerobic” bacteria in the chicks receiving dietary antibiotics. No persistent changes were seen in the numbers of coliform bacteria. Lactobacilli were not detected in any of the groups until 3 weeks after feeding.
Viability of
Bacillus subtilis
Spores in Rocket Propellants
Authors: Godding Rogene M. , Lynch Victoria H.
Published: December 2020

The sporicidal activity of components used in liquid and solid rocket propellants was tested by use of spores of
Bacillus subtilis
dried on powdered glass. Liquid propellant ingredients tested were N
2
O
4
, monomethylhydrazine and 1,1-dimethylhydrazine. N
2
O
4
was immediately sporicidal; the hydrazines were effective within several days. Solid propellants consisted of ammonium perchlorate in combination with epoxy resin (EPON 828), tris-1-(2-methyl) aziridinyl phosphine oxide, bis-1-(2-methyl) aziridinyl phenylphosphine oxide, and three modified polybutadiene polymers. There was no indication of appreciable sporicidal activity of these components.