CANADIAN WILTSHIRE BACON: XVIII. EFFECT OF TEMPERATURE AND BACTERIAL GROWTH ON NITRITE CONTENT

1941 ◽  
Vol 19d (3) ◽  
pp. 104-111
Author(s):  
W. Harold White ◽  
N. E. Gibbons
Keyword(s):  
Bacterial Growth ◽  
Effect Of Temperature ◽  
Bacterial Populations ◽  
Nitrite Content

Samples of bacon, with bacterial populations adjusted to two levels, were held at temperatures of 4°, 21°, 38°, and 55 °C. for 20, 40, 80, and 160 hr. Both the total number of organisms and the number capable of reducing nitrate to nitrite were significantly correlated with the nitrite content. Furthermore, the samples adjusted to the high bacterial level usually contained more nitrite after treatment than those from the same hog but containing fewer bacteria. The increase in nitrite, observed here and previously, at temperatures below 55 °C., is attributable primarily to bacterial growth and not to enzymes or other constituents of the bacon.

EFFECT OF TEMPERATURE ON THE PATHOGENESIS OF BACILLUS THURINGIENSIS BERLINER IN LARVAE OF THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA CLEM. (LEPIDOPTERA: TORTRICIDAE)

1994 ◽  
Vol 126 (4) ◽  
pp. 1061-1065 ◽  
Author(s):  
Kees van Frankenhuyzen
Keyword(s):  
Bacillus Thuringiensis ◽  
Bacterial Growth ◽  
Choristoneura Fumiferana ◽  
Larval Mortality ◽  
Lethal Dose ◽  
Spruce Budworm ◽  
Effect Of Temperature ◽  
Vegetative Cells ◽  
Time Required ◽  
Peak Abundance

AbstractThe relationship between temperature and pathogenesis of Bacillus thuringiensis Berliner var. kurstaki in infected larvae of the eastern spruce budworm, Choristoneura fumiferana Clem., was investigated to determine if more rapid death of larvae with an increase in temperature could be accounted for by enhanced bacterial growth. Cumulative mortality of larvae force-fed with a lethal dose of HD-1-S-1980 peaked within 2 days at 25 °C, 3 days at 19 °C, 7 days at 16 °C, and 21 days at 13 °C. The progress of bacterial growth in the larvae was followed from spore germination to cell lysis, and was completed within 4 days at 25 °C, 6 days at 22 °C, 12 days at 19 °C, 14 days at 16 °C, and > 28 days at 13 °C. Peak abundance of vegetative cells in the larvae was observed after 1 day at 25 °C, 2 days at 22 °C, 3 days at 19 °C, 7 days at 16 °C, and 21 days at 13 °C, and thus coincided almost exactly with the time required for maximum larval mortality. This correlation suggests that the observed effect of temperature on progression of larval mortality was due to its effect on the proliferation of vegetative cells in the infected larvae, and that bacterial septicemia makes an important contribution to death.

scholarly journals Heterogeneous ceramide distributions alter spatially resolved growth of Staphylococcus aureus on human stratum corneum

2018 ◽  
Vol 15 (141) ◽  
pp. 20170848 ◽  
Author(s):  
Joseph M. Cleary ◽  
Zachary W. Lipsky ◽  
Minyoung Kim ◽  
Cláudia N. H. Marques ◽  
Guy K. German
Keyword(s):  
Staphylococcus Aureus ◽  
Stratum Corneum ◽  
Bacterial Growth ◽  
Disease Transmission ◽  
Bacterial Species ◽  
Causal Link ◽  
Bacterial Populations ◽  
Human Stratum Corneum ◽  
Spatially Resolved ◽  
Skin Cleansing

Contemporary studies have revealed dramatic changes in the diversity of bacterial microbiota between healthy and diseased skin. However, the prevailing use of swabs to extract the microorganisms has meant that only population ‘snapshots’ are obtained, and all spatially resolved information of bacterial growth is lost. Here we report on the temporospatial growth of Staphylococcus aureus on the surface of the human stratum corneum (SC); the outermost layer of skin. This bacterial species dominates bacterial populations on skin with atopic dermatitis (AD). We first establish that the distribution of ceramides naturally present in the SC is heterogeneous, and correlates with the tissue's structural topography. This distribution subsequently impacts the growth of bacterial biofilms. In the SC retaining healthy ceramide concentrations, biofilms exhibit no spatial preference for growth. By contrast, a depletion of ceramides consistent with reductions known to occur with AD enables S. aureus to use the patterned network of topographical canyons as a conduit for growth. The ability of ceramides to govern bacterial growth is confirmed using a topographical skin canyon analogue coated with the ceramide subcomponent d -sphingosine. Our work appears to explain the causal link between ceramide depletion and increased S. aureus populations that is observed in AD. It may also provide insight into disease transmission as well as improving pre-operative skin cleansing techniques.

scholarly journals Sciadopitys verticillata Resin: Volatile Components and Impact on Plant Pathogenic and Foodborne Bacteria

Molecules ◽  
2019 ◽  
Vol 24 (20) ◽  
pp. 3767
Author(s):  
David I. Yates ◽  
Bonnie H. Ownley ◽  
Nicole Labbé ◽  
Joseph J. Bozell ◽  
William E. Klingeman ◽  
...  
Keyword(s):  
Bacterial Growth ◽  
Foodborne Pathogens ◽  
Antimicrobial Properties ◽  
Principal Component ◽  
Gas Chromatography Mass Spectrometry ◽  
Volatile Components ◽  
Sample Treatment ◽  
Bacterial Populations ◽  
Sciadopitys Verticillata ◽  
The Impact

Sciadopitys verticillata (Sv) produces a white, sticky, latex-like resin with antimicrobial properties. The aims of this research were to evaluate the effects of this resin (Sv resin) on bacterial populations and to determine the impact of its primary volatile components on bioactivity. The impact of sample treatment on chemical composition of Sv resin was analyzed using Fourier transform infrared spectroscopy (FTIR) coupled with principal component analysis. The presence and concentration of volatiles in lyophilized resin were determined using gas chromatography/mass spectrometry (GC/MS). Changes in bacterial population counts due to treatment with resin or its primary volatile components were monitored. Autoclaving of the samples did not affect the FTIR spectra of Sv resin; however, lyophilization altered spectra, mainly in the CH and C=O regions. Three primary bioactive compounds that constituted >90% of volatiles (1R-α-pinene, tricyclene, and β-pinene) were identified in Sv resin. Autoclaved resin impacted bacterial growth. The resin was stimulatory for some plant and foodborne pathogens (Pseudomonas fluorescens, P. syringae, and Xanthomonas perforans) and antimicrobial for others (Escherichia coli, Bacillus cereus, Agrobacterium tumefaciens, and Erwinia amylovora). Treatment with either 1R-α-pinene or β-pinene reduced B. cereus population growth less than did autoclaved resin. The complex resin likely contains additional antimicrobial compounds that act synergistically to inhibit bacterial growth.

scholarly journals Adaptation of Fire Blight Forecasting to Optimize the Use of Biological Controls

Plant Disease ◽  
2004 ◽  
Vol 88 (1) ◽  
pp. 41-48 ◽  
Author(s):  
K. B. Johnson ◽  
V. O. Stockwell ◽  
T. L. Sawyer
Keyword(s):  
Bacterial Growth ◽  
Fire Blight ◽  
Disease Risk ◽  
Risk Index ◽  
Growth Index ◽  
Disease Suppression ◽  
Effect Of Temperature ◽  
Effective Population ◽  
Decision Matrix ◽  
Risk Indices

We investigated adaptation of fire blight forecasting concepts to incorporate and optimize the use of biological agents for disease suppression. The effect of temperature on growth of the bacterial antagonists, Pseudomonas fluorescens A506 and Pantoea agglomerans C9-1S, and of the pathogen Erwinia amylovora153N, on pear and apple blossoms was evaluated in growth chamber and screenhouse experiments. New blossoms were inoculated with the strains and subsequent growth was measured over 96 h. Bacterial growth rates on blossoms were described as functions of temperature. A degree hour-based “bacterial growth index” (96-h moving total of degree hours >10°C) was created to assess conduciveness of orchard environments for antagonist colonization. A comparison of this index to a disease risk index indicated that biocon-trol treatments could be timed such that the antagonists could be expected to grow to an effective population size before the disease index shifted from “low” to “moderate” risk. For six pear- and apple-production areas of Oregon and Washington, regression of actual values of the bacterial growth and disease risk indices on index values derived from 4-day temperature forecasts resulted in coefficients of determination that averaged 0.75. The “bacterial growth index” and its estimation via temperature forecasts were incorporated into a decision matrix designed to guide optimal treatment timing.

Expression of resistance in bean pods to an incompatible isolate of Pseudomonas syringae

1977 ◽  
Vol 55 (15) ◽  
pp. 2043-2052 ◽  
Author(s):  
D. M. Webster ◽  
L. Sequeira
Keyword(s):  
Pseudomonas Syringae ◽  
Bacterial Growth ◽  
Ethanolic Extract ◽  
Fresh Weight ◽  
Inoculum Level ◽  
Bacterial Populations ◽  
Progressive Decline ◽  
High Inoculum ◽  
Inhibitory Compounds ◽  
Extract Fraction

Isolates of Pseudomonas syringae from hairy vetch were either virulent (compatible) or avirulent (incompatible) to bean. When bean pods were injected at high inoculum levels (5 × 107 cells/ml), both compatible and incompatible isolates multiplied rapidly and caused water-soaking of injected tissues; populations of both isolates were similar at the end of log phase. Lesions caused by the incompatible isolate turned brown by 3 days after inoculation and did not expand; those caused by the compatible isolate remained water-soaked and expanded into the adjoining, noninoculated tissues. At low inoculum levels (5 × 104 cells/ml), the compatible isolate exhibited the same pattern of multiplication and lesion development as at the high inoculum level. The incompatible isolate, on the other hand, caused necrotic flecking within the injected area by 24 h, and these small lesions remained limited. Appearance of the necrotic flecks was correlated with a progressive decline in bacterial populations; after5 days, the population of incompatible bacteria was about a hundredfold lower than that of compatible ones. Populations of incompatible bacteria within and between the necrotic flecks declined rapidly, indicating the potential accumulation of inhibitors of bacterial growth as a result of an inducible resistance mechanism.The phytoalexin phaseollin reached 280 μg/g fresh weight by 3 days after inoculation of bean pods with incompatible bacteria. However, this compound was not involved in resistance. Neither compatible nor incompatible isolates of the bacterium were significantly inhibited when grown in a medium saturated with phaseollin. When other antibiotic substances in plant extracts were sought, substantial amounts of inhibitory compounds were detected only in the ethanolic extract (fraction soluble in ethyl acetate) of pods previously inoculated with an incompatible isolate of P. syringae. Only low levels of inhibition were obtained from identical extracts of uninfected pods or from pods inoculated with a compatible isolate of P. syringae. Bacterial growth was completely prevented in a bean infusion medium containing 1 g fresh weight equivalent of pod tissue challenged with the incompatible isolate. The active compound(s) was nonfluorescent, had a UV absorption maximum at 286 nm, and gave a positive reaction with reagents for phenolic compounds.

scholarly journals The growth of bacterial colonies and their viable population

1947 ◽  
Vol 45 (1) ◽  
pp. 19-27 ◽  
Author(s):  
Anna Mayr-Harting
Keyword(s):  
Bacterial Growth ◽  
Bacterial Populations ◽  
Fluid Media ◽  
Viable Population

The numerical aspects of bacterial growth have hitherto been investigated chiefly in fluid media and the laws governing the development of bacterial populations in fluid cultures are known in some detail.

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