scholarly journals The conformability of two equations for bacterial growth in pork

2011 ◽  
Vol 20 (No. 2) ◽  
pp. 69-73
Author(s):  
M. Miyahara ◽  
T. Matsumoto ◽  
H. Sakurai ◽  
P. Pipek
Keyword(s):  
Exponential Function ◽  
Bacterial Growth ◽  
Growth Curve ◽  
Salt Solution ◽  
Functional Equations ◽  
Physiological Salt Solution ◽  
Initial Number ◽  
Natural Logarithm ◽  
Number Of Bacteria

Pork is now distributed as cut meat, which increases the chance of contamination with bacteria. The rate of bacterial growth can be expressed by an exponential function. In order to find how the number of contaminating bacteria increases, we compared two functional equations for a growth curve. They are logistic: Yt = K (1 + m e–at) (1) and Gompertz: log Yt = log K + (log a)bt (2) equations (where Yt = the number of bacteria at the time t in min, m and a = coefficient, e = natural logarithm, K maximum number of bacteria). 90 ml of physiological salt solution was added to 10 g of pork. It was homogenized for 3 min, then incubated at 35°C for 13 hrs. The number of bacteria was counted every hour. We found from these data that the above two equations can be expressed as follows: Yt = 23 535 (1 + 16269 e–1.1608t) and log Yt = 8.9940 + (–3.1124) × 0.7839t. The theoretical and actual values matched well in equation (1), and the number of bacteria can be predicted accurately using this equation at a given time after incubation. The theoretical and actual values did not match well in equation (2) and its accuracy to predict the number of bacteria was very low except the initial number of bacteria was high.  

scholarly journals A new analysis method for evaluating bacterial growth with microplate readers

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0245205
Author(s):  
Venkata Rao Krishnamurthi ◽  
Isabelle I. Niyonshuti ◽  
Jingyi Chen ◽  
Yong Wang
Keyword(s):  
Bacterial Growth ◽  
Growth Curve ◽  
Fluorescent Proteins ◽  
Growth Curves ◽  
Gompertz Model ◽  
Analysis Method ◽  
Bacterial Cultures ◽  
Derivatives Of ◽  
Number Of Bacteria ◽  
Growth Of Bacteria

Growth curve measurements are commonly used in microbiology, while the use of microplate readers for such measurements provides better temporal resolution and higher throughput. However, evaluating bacterial growth with microplate readers has been hurdled by barriers such as multiple scattering. Here, we report our development of a method based on the time derivatives of the optical density (OD) and/or fluorescence (FL) of bacterial cultures to overcome these barriers. First, we illustrated our method using quantitative models and numerical simulations, which predicted the number of bacteria and the number of fluorescent proteins in time as well as their time derivatives. Then, we systematically investigated how the time derivatives depend on the parameters in the models/simulations, providing a framework for understanding the FL growth curves. In addition, as a demonstration, we applied our method to study the lag time elongation of bacteria subjected to treatment with silver (Ag+) ions and found that the results from our method corroborated well with that from growth curve fitting by the Gompertz model that has been commonly used in the literature. Furthermore, this method was applied to the growth of bacteria in the presence of silver nanoparticles (AgNPs) at various concentrations, where the OD curve measurements failed. We showed that our method allowed us to successfully extract the growth behavior of the bacteria from the FL measurements and understand how the growth was affected by the AgNPs.

scholarly journals DATA ON THE DEVELOPMENT OF HETERAKIS PAPILLOSA IN THE FOWL

1921 ◽  
Vol 34 (3) ◽  
pp. 259-270 ◽  
Author(s):  
H. W. Graybill
Keyword(s):  
Small Intestine ◽  
Salt Solution ◽  
Final Stage ◽  
Minimum Temperature ◽  
Growth And Development ◽  
Room Temperature ◽  
Freezing Temperature ◽  
Physiological Salt Solution ◽  
Natural Conditions ◽  
Short Intervals

In observations on the development of the ova of Heterakis papillosa in cultures, it was found that they failed to develop at a temperature ranging from 2.5–8°C., but developed slowly at a temperature of 11.5–13.5°C. The minimum temperature for development seems to lie between 8° and 11.5–13.5°C. At temperatures ranging in various cultures from 18–29°C. ova developed to their final stage in 7 to 12 days. Undeveloped ova subjected to a freezing temperature for a period of 4 days were viable at the end of that time. Fully developed ones remained alive when exposed out of doors for a period of 7 days at a temperature ranging from 5–62°F. Undeveloped ova survived desiccation at room temperature for a period of 16 days, but not for 41 days. Fully developed eggs were alive after desiccation for 18 days, but not after 49 days. In another instance they were no longer viable after 10 days. Embryos within ova kept in physiological salt solution at room temperature survived during a period of a little over 12 months. Fully developed ova kept in soil outdoors under circumstances approaching natural conditions contained living embryos after a period of 8 months. From a study of a series of artificially infested chickens killed at short intervals it appears that the ova of Heterakis hatch in the small intestine and the larvæ pass by way of the small and large intestines to the ceca where they undergo development to maturity. Larvæ found in the mucosa of the ceca were not in an encysted condition. Feeding of numerous artificially incubated ova may lead to a light infestation, the cause of which has not been definitely determined. A period of 57 days was required for larvæ to reach maturity in a host. The entire cycle from egg to adult requires a minimum time of about 64 days. A brief study of the growth and development of larvæ within the host has been made. No evidence was found of a migration through the tissues. A few penetrate into the mucosa of the ceca.

Potassium-induced relaxation of arteries in hypertension: modulation by extracellular calcium

1989 ◽  
Vol 256 (3) ◽  
pp. H707-H712 ◽  
Author(s):  
G. Rinaldi ◽  
D. F. Bohr
Keyword(s):  
Smooth Muscle ◽  
Plasma Membrane ◽  
Salt Solution ◽  
Binding Sites ◽  
Muscle Relaxation ◽  
Smooth Muscle Relaxation ◽  
Physiological Salt Solution ◽  
Spontaneously Hypertensive ◽  
Na Pump ◽  
Wistar Kyoto

Smooth muscle relaxation due to activation of Na+-K+-adenosinetriphosphatase (ATPase) (K+ relaxation) was studied in isolated tail arteries from stroke-prone spontaneously hypertensive (SHRSP) and Wistar-Kyoto (WKY) rats. Exposure to K+ (7 mM) relaxed a norepinephrine (1 microM) contraction induced in K+-free physiological salt solution (PSS) by 46 +/- 3% in WKY and by 81 +/- 3% in SHRSP. Incubation with monensin (10 microM) augmented the K+-relaxation in WKY to 61 +/- 5%. Incubation with amiloride (10 microM) or with low-Na+ (10 mM) PSS attenuated the K+ relaxation in SHRSP to 34 +/- 3 and 5 +/- 2%, respectively. Incubation with high-Ca2+ (6.6 mM) PSS attenuated the K+ relaxation in WKY to 25 +/- 3% but resulted in only a slight decrease in the relaxation in SHRSP (to 73 +/- 2%). We conclude 1) that a greater Na+ leakiness of the plasma membrane in SHRSP than in WKY while the Na+ pump is inactive in K+-free PSS can explain the greater relaxation observed when the Na+ pump is reactivated and 2) that the Na+ leakiness of the membrane is more attenuated by Ca2+ in the WKY than in the SHRSP. We hypothesize that this Ca2+ effect reflects a normally large amount of this ion that can be bound to and thereby stabilize the membrane of the WKY, decreasing its permeability to Na+. The membrane of the SHRSP is deficient in its Ca2+-binding sites. Hence the added Ca2+ does not further stabilize its membrane.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Sarcoplasmic reticulum and endothelium independently regulate venous smooth muscle [Ca2+]iand contraction

1999 ◽  
Vol 277 (2) ◽  
pp. H749-H755
Author(s):  
Régent Laporte ◽  
Ismail Laher
Keyword(s):  
Smooth Muscle ◽  
Steady State ◽  
Sarcoplasmic Reticulum ◽  
Salt Solution ◽  
Isometric Contraction ◽  
Cyclopiazonic Acid ◽  
Physiological Salt Solution ◽  
Sustained Contraction ◽  
Facial Vein ◽  
State Increase

In rings of rabbit facial vein (RFV), depletion of sarcoplasmic reticulum (SR) Ca2+ by caffeine abolished the subsequent isometric contraction to 25 mM K+ physiological salt solution (25K-PSS). However, the associated steady-state increase of smooth muscle intracellular free Ca2+concentration ([Ca2+]i), measured using fura PE3 and cuvette photometry, was not altered. Treatment with the specific SR Ca2+ pump inhibitor cyclopiazonic acid (30 μM) after caffeine-induced SR Ca2+ depletion restored and greatly augmented the 25K-PSS-induced contraction. This suggests that SR Ca2+ depletion leads to a dissociation of K+-induced [Ca2+]iincrease from contraction that was dependent on Ca2+ pump-mediated SR Ca2+ uptake. Endothelium removal augmented the 25K-PSS-induced [Ca2+]iincrease after caffeine-induced SR Ca2+ depletion. However, this was associated with only a small and transient contraction. Exposure of endothelium-denuded RFV to cyclopiazonic acid after caffeine-induced SR Ca2+ depletion further amplified the 25K-PSS-induced [Ca2+]iincrease, which was associated with a large and sustained contraction. However, the latter [Ca2+]iincrease was still higher than in endothelium-intact RFV. This suggests that the endothelium dampens the [Ca2+]irise associated with K+-induced Ca2+ influx, but independently of Ca2+ pump-mediated SR Ca2+ uptake.

Deformability of thermoplastics in physiological salt solution

1978 ◽  
Vol 14 (2) ◽  
pp. 263-268
Author(s):  
G. I. Roitberg ◽  
R. Z. Rakhimov ◽  
A. K. Valiev
Keyword(s):  
Salt Solution ◽  
Physiological Salt Solution

scholarly journals Influence du pH du milieu au cours de la fécondation sur la survie embryonnaire de la carpe commune (Cyprinus carpio)

1984 ◽  
Vol 62 (5) ◽  
pp. 851-861 ◽  
Author(s):  
P. Roubaud ◽  
Ch. Gillet ◽  
R. Billard
Keyword(s):  
Cyprinus Carpio ◽  
Salt Solution ◽  
Physiological Salt Solution ◽  
Embryonic Survival ◽  
Ph Values ◽  
Normal Fertilization

The effects of environmental pH during fertilization in carp eggs were studied by measuring the percentage of prehatching embryonic survival. These effects, which may be delayed beyond epiboly, were the same when the treatments lasted 15 and 30 min after insemination, and they were not modified either by the addition of a physiological salt solution to the medium or by exposure of the eggs for 10 s before insemination. Among the six types of buffer used, phosphate buffers were particularly toxic which may indicate the role played by calcium during fertilization. Normal fertilization requires that the osmolarity of the medium be lower than or equal to 200 mosmol/kg. Beyond the limits of favorable pH values (7.2 and 9.6), egg tolerance decreased less rapidly in a weakly buffered medium than in a strongly buffered one. In such a medium, there was no resistance at pH 6.2 or 9.9.

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