Thermal and water source effects upon the stability of enteroviruses in surface freshwaters

1989 ◽  
Vol 35 (4) ◽  
pp. 474-480 ◽  
Author(s):  
Christon J. Hurst ◽  
William H. Benton ◽  
Kim A. McClellan
Keyword(s):  
Bacterial Growth ◽  
Incubation Temperature ◽  
Water Source ◽  
Inactivation Rate ◽  
Human Enterovirus ◽  
Strongly Correlated ◽  
Artificial Lake ◽  
Viral Inactivation ◽  
Term Survival ◽  
Incubation Temperatures

The long-term survival of three human enterovirus serotypes, Coxsackievirus B3, echovirus 7, and poliovirus 1 was examined in samples of surface freshwater collected from five sites of physically different character. These were an artificial lake created by damming a creek, a small groundwater outlet pond, both a large- and a medium-sized river, and a small suburban creek. Survival was studied at temperatures of −20, 1, and 22 °C. The average amount of viral inactivation was 6.50–7.0 log10 units over 8 weeks at 22 °C, 4–5 log10 units over 12 weeks at 1 °C, and 0.4–0.8 log10 units over 12 weeks at −20 °C. The effect of incubation temperature upon viral inactivation rate was statistically significant (p < 0.00001). As determined by pairing tests, survival was also significantly related to both viral serotype and water source at each of the three incubation temperatures (p ≤ 0.05). Efforts were made to determine whether the rate of viral inactivation observed at the different incubation temperatures was related to characteristics inherent to the water that was collected from the different locations. The characteristics examined included physical and chemical parameters, indigenous bacterial counts, and the amount of bacterial growth that the waters would support (measured as the maximum number of generations which seeded bacteria could undergo after being placed into either pasteurized or sterile-filtered water samples). Analysis of viral inactivation rate versus these characteristics revealed three apparent effectors of viral persistence. These were (i) hardness and conductivity, both of which strongly correlated with one another; (ii) turbidity and suspended solids content, both of which strongly correlated with one another; and (iii) the number of generations of bacterial growth that a sample was capable of supporting, which also correlated with hardness and conductivity.Key words: virus, survival, inactivation rate, water.

FUNGI IN FOODS V. RESPONSE OF NATURAL POPULATIONS TO INCUBATION TEMPERATURES BETWEEN 12 AND 32 C1

1973 ◽  
Vol 36 (8) ◽  
pp. 434-435 ◽  
Author(s):  
John A. Koburger
Keyword(s):  
Bacterial Growth ◽  
Incubation Temperature ◽  
Natural Populations ◽  
Incubation Temperatures

The effect of incubation temperatures from 12 to 32 C on yeast and mold counts was determined using both antibiotic and acidified media to control bacterial growth. Highest counts were obtained on the antibiotic medium. Lowest counts occurred with both media at 32 C. Little difference in recovery was apparent in the range of 12 to 27 C, with the fungi responding in a similar manner in both media to shifts in incubation temperature.

Behaviour of Coli Phages in Oxidation Ponds

1985 ◽  
Vol 17 (10) ◽  
pp. 219-227 ◽  
Author(s):  
T. Omura ◽  
H. K. Shin ◽  
A. Ketratanakul
Keyword(s):  
Laboratory Experiments ◽  
Field Investigation ◽  
Host Cells ◽  
Coliform Bacteria ◽  
Alkaline Ph ◽  
Viral Inactivation ◽  
Effects Of Temperature ◽  
Oxidation Ponds ◽  
Incubation Temperatures ◽  
Inactivation Efficiency

Coliphages are among the most promising indicators of viral inactivation efficiency of wastewater treatment. Therefore, it is important to investigate the behaviour of coliphages in oxidation ponds from the viewpoint of predicting the inactivation of infectious viruses. In this study, numbers of coliphages were measured in oxidation ponds consisting of a series of facultative and maturation ponds. In parallel with this investigation, the effects of temperature and pH on the behaviour of coliphages were examined in the laboratory, employing three species of coliform bacteria as host cells. The field investigation showed that there was positive correlation between counts of coliphages and those of coliform bacteria, and that more than 99% of coliphages were inactivated. The inactivation efficiency of coliphages in the facultative pond was much higher than in the maturation pond. The results of the laboratory experiments indicated that at 30°C more than 99% of the coliform group were destroyed in 7 days of incubation and that coliphages counts increased from 105/100 ml to 107/100 ml with a lag time of 3 days. Greater reduction of the coliform count was obtained at higher incubation temperatures. It was observed that the coliphages possessed greater ability to attack coliform bacteria at acidic rather than alkaline pH.

Phytotoxic Effect of Decaying Quackgrass (Agropyron repens) Residues

Weed Science ◽  
1979 ◽  
Vol 27 (6) ◽  
pp. 595-598 ◽  
Author(s):  
T. V. Toai ◽  
D. L. Linscott
Keyword(s):  
Incubation Temperature ◽  
Soil Surface ◽  
Water Soluble ◽  
Water Extracts ◽  
Phytotoxic Activity ◽  
Phytotoxic Effect ◽  
Effects Of Temperature ◽  
Incubation Temperatures ◽  
Toxin Formation ◽  
Agropyron Repens

We studied the effects of temperature (5, 10, 20, and 30 C) on the phytotoxic activity of decaying quackgrass [Agropyron repens (L.) Beauv.] leaves and rhizomes that were incubated in soils for 0, 1, 2, 4, and 6 weeks. Alfalfa (Medicago sativa L.) seeds were grown for 96 h in water, water extracts of control soils, and water extracts of soil with quackgrass rhizomes or leaves. Dried quackgrass rhizomes and leaves contained water-soluble toxins that inhibited alfalfa seedling development and growth. There was a strong interaction between incubation time and temperature on the development of additional toxins by decomposing quackgrass. High incubation temperature (30 C) accelerated toxin formation and ultimate decay. Intermediate temperature (20 C) delayed toxin formation and decay. Low incubation temperatures (5 C and 10 C) prevented formation of additional toxin. In all extracts of quackgrass and soil that had been incubated for 6 weeks, normal alfalfa seedling number equaled that in water. However, seedling growth varied with incubation temperatures.Treatment of quackgrass with glyphosate [N-(phosphonomethyl) glycine] in the greenhouse did not influence the toxicity of decaying quackgrass leaves. The highest toxic effect was noted after 1 week of decay on the soil surface.

Nest temperature´s influence on morphology of Dermochelys coriacea hatchlings incubated in hatcheries in Oaxaca, Mexico

2021 ◽  
Author(s):  
Jesús García-Grajales ◽  
Juan Francisco Meraz ◽  
José Luis Arcos García ◽  
Eustacio Ramírez Méndez
Keyword(s):  
Incubation Temperature ◽  
Carapace Width ◽  
Principal Component ◽  
Dermochelys Coriacea ◽  
Egg Mass ◽  
Natural Environments ◽  
Data Logger ◽  
Geometric Morphometric ◽  
Low Weight ◽  
Incubation Temperatures

The influence of nest incubation temperatures on the carapace shape and morphological traits of Dermochelys coriacea (Vandelli 1761) hatchlings incubated in two hatcheries of Oaxaca, Mexico was evaluated. This study was carried out from October 2016 through May 2017. On each beach, there are community groups consisting of volunteers without association with universities, that protect and relocate the nests to increase hatching success. In each translocated nest, a data logger was placed in the centre of the egg mass. Hatchlings were collected as they emerged from each nest. The carapaces of the hatchlings were photographed and subjected to geometric morphometric analysis; later, hatchlings were weighed and their bodies were measured. The mean temperature of 12 nests in each hatchery were recorded, with no significant differences between hatcheries. The principal component analysis (PCA) revealed an overlapping of the carapace shape under different duration of temperature. Temperature had a significant influence on hatchling morphology. Higher mean incubation temperatures produced hatchlings with low weight, smaller appendage; narrower carapace width and shorter flippers length. Lower mean incubation temperatures produced hatchlings that had greater weight, greater appendage width, wider carapace width and longer flipper length. Results indicate that the D. coriacea hatchlings incubated in hatcheries demonstrate morphology that varies in relation to nest incubation temperature in a similar way to hatchlings produced in natural environments.

scholarly journals Effects of constant incubation regimes on eggs and hatchlings of the egg-laying skink, Oligosoma suteri

2021 ◽  
Author(s):  
◽  
Kelly Maree Hare
Keyword(s):  
Hatching Success ◽  
Incubation Temperature ◽  
Unit Length ◽  
Condition Index ◽  
Egg Laying ◽  
Maternal Influence ◽  
Temperature Dependent ◽  
Sprint Speed ◽  
Fitness Traits ◽  
Incubation Temperatures

<p>The conditions under which reptilian eggs are incubated affect survival probability and physiological attributes of the progeny. The egg-laying skink, Oligosoma suteri, is the only endemic oviparous lizard in New Zealand. No controlled laboratory incubation had previously been undertaken, and thus no information was available on the requirements for successful captive incubation. I studied the effects of incubation regime on the eggs and hatchlings of O. suteri to four months of age. Oligosoma suteri eggs (n = 174) were randomly distributed among three constant incubation temperatures (18°C, 22°C and 26°C) and two water potentials (-120 kPa and -270 kPa). Hatching success and hatchling survival were greatest at 22°C and 26°C, with hatchlings from 18°C incubation suffering from physical abnormalities. Incubation regime and maternal influence did not affect sex of individuals, with equal sex ratios occurring from each incubation treatment. Hatchlings from the 22°C and -120 kPa incubation treatments were larger, for most measurements, and warmer incubation temperatures resulted in increased growth rates. Juveniles from 22°C and 26°C and individuals with greater mass per unit length (condition index) sprinted faster over 0.25 m. Sprint speed was positively correlated with ambient temperature. At four months of age sprint speed decreased in 18°C individuals and individuals incubated at 26°C and -270 kPa compared to their performance at one month. The results suggest that the most successful captive incubation regime for O. suteri is 22°C and -120 kPa. This study also shows that temperature-dependent sex determination does not occur in O. suteri, but that fitness traits are influenced by incubation temperature.</p>

Baseflow recession characterization and groundwater storage trends in northern Taiwan

2017 ◽  
Vol 48 (6) ◽  
pp. 1745-1756 ◽  
Author(s):  
Kun-Ta Lin ◽  
Hsin-Fu Yeh
Keyword(s):  
Water System ◽  
Water Source ◽  
River Basins ◽  
Mean Value ◽  
Strongly Correlated ◽  
Groundwater Storage ◽  
Drainage Time ◽  
Terrestrial Water ◽  
Channel Slope ◽  
Northern Taiwan

Abstract Groundwater is a critical component of the terrestrial water budget and acts as a relatively stable water source in Taiwan. In the present study, river basins' characterization and groundwater storage trends in northern Taiwan are analyzed using the Brutsaert method. As groundwater storage sustains baseflows in a water system during dry periods, it can be assessed directly from the streamflow record. The characteristic drainage time scale value, K, varied between 34 and 84 days, with a mean value of 54 days and a standard deviation of 16 days. From correlation analysis, K is strongly correlated with the main channel slope. Based on annual values of groundwater storage over the period of record, five subbasins showed downward trends, ranging from −0.053 to −0.950 mm/year, and three subbasins exhibited upward trends, ranging from 0.111 to 0.141 mm/year. During the period of 2000–2014, the groundwater storage trends in northern Taiwan had an obvious spatial distribution. River basins with significant negative trends (mean value of −2.729 mm/year) are located in the northeast part of the study area. In contrast, the subbasins in the northwest part all showed positive trends (mean value of 0.944 mm/year) in groundwater storage.

Effect of Temperature on Growth and Alpha Toxin Production by Clostridium perfringens1

1979 ◽  
Vol 42 (11) ◽  
pp. 848-851 ◽  
Author(s):  
Y. PARK ◽  
E. M. MIKOLAJCIK
Keyword(s):  
Growth Phase ◽  
Incubation Temperature ◽  
Ground Beef ◽  
Population Level ◽  
Toxin Production ◽  
Stationary Growth Phase ◽  
Effect Of Temperature ◽  
Alpha Toxin ◽  
Stationary Growth ◽  
Incubation Temperatures

Growth and alpha toxin production by a strain of Clostridium perfringens was determined in Thioglycollate medium, beef broth with ground beef, and beef broth with ground beef and soy protein. Incubation temperatures ranged from 15 to 50 C. In Thioglycollate medium, maximum alpha toxin production occurred at 35 C and was 40 times greater than that observed at 45 C. However, generation time and maximum population were approximately the same at 35 and 45 C. At 15 C, a two log cycle reduction in viable counts occurred within 6 h. Irrespective of incubation temperature, alpha toxin levels in Thioglycollate medium declined as the incubation period was extended beyond the stationary growth phase. In the beef broth with ground beef system which was studied at 35 C only, the organism grew slower and produced less toxin than in Thioglycollate medium. The amount of alpha toxin detected was influenced to a greater extent by the incubation time and temperature, the holding time beyond the stationary growth phase, and the growth medium than by the population level of C. perfringens.

scholarly journals Effects of Temperature and Duration of Preconditioning Cold Treatment on Sclerotial Germination of Claviceps purpurea

Plant Disease ◽  
2016 ◽  
Vol 100 (10) ◽  
pp. 2080-2086 ◽  
Author(s):  
Sai Sree Uppala ◽  
B. M. Wu ◽  
S. C. Alderman
Keyword(s):  
Incubation Temperature ◽  
Cold Treatment ◽  
Kentucky Bluegrass ◽  
Claviceps Purpurea ◽  
Willamette Valley ◽  
Spore Trap ◽  
C Cycle ◽  
Incubation Temperatures ◽  
Ascospore Production ◽  
Sclerotial Germination

Claviceps purpurea is an important ovary-infecting pathogen that replaces seed with sclerotia in Kentucky bluegrass grown for seed. Sclerotia overwinter in the soil and germinate in the spring to produce ascospores that infect grass seed ovaries. To better understand environmental conditions affecting ascospore production, the effects of preconditioning cold treatment and subsequent incubation temperature on germination of sclerotia were determined in growth chambers under controlled conditions. Preconditioning cold treatment was essential for germination only in treatments where the incubation temperature was high (at least higher than 20°C). At lower incubation temperatures (10 to 20°C), preconditioning also played a role in improving sclerotial germination. Preconditioning at 4°C (in darkness) for 4 to 8 weeks followed by incubation at 10 and 20°C (cycle of 12 h each of darkness and light), or constant 15°C (cycle of 12 h each of darkness and light), was optimal for ergot germination. When sclerotia were preconditioned for 4 weeks or longer, number of incubation days required for initiation of germination was not affected by temperature in the range from 10 to 25°C (cycle of 12 h each of darkness and light), although the duration of germination (or the progress speed of germination) was still affected by temperature. A simple model was developed based on laboratory results and validated with historic spore trap data collected from various Kentucky bluegrass fields in Oregon (Willamette Valley, central Oregon, and Grande Ronde Valley). The prediction model could predict ascospore onset well and explained 55% of variation in the data.

scholarly journals Effects of temperature on the composition and diversity of bacterial communities in bamboo soils at different elevations

2017 ◽  
Vol 14 (21) ◽  
pp. 4879-4889 ◽  
Author(s):  
Yu-Te Lin ◽  
Zhongjun Jia ◽  
Dongmei Wang ◽  
Chih-Yu Chiu
Keyword(s):  
Soil Respiration ◽  
Bacterial Diversity ◽  
Bacterial Communities ◽  
Incubation Temperature ◽  
Principal Component ◽  
Scaling Analysis ◽  
Mountain Areas ◽  
Bacterial Structure ◽  
Incubation Temperatures ◽  
The Impact

Abstract. Bamboo is an important resource distributed in mountain areas in Asia. Little is known about the impact of temperature changes on bamboo soil bacterial communities. In this study, responses of bacterial communities collected at 600, 1200, and 1800 m to different incubation temperatures (15, 20, and 35 °C) were examined using barcoded pyrosequencing and soil analyses. Soil respiration was greater at higher elevation and incubation temperature. The bacterial diversity decreased after 112 days of incubation at 35 °C. Before incubation, Acidobacteria and Proteobacteria were the most abundant phyla in all communities. The relative abundance of Acidobacteria generally decreased after 112 days of incubation at the three temperatures. α-Proteobacteria showed a similar trend, while γ-Proteobacteria increased after incubation, except in samples from 1800 m incubated at 35 °C. Non-metric multi-dimensional scaling analysis revealed structural variability under different incubation times and temperatures. Principal component analysis indicated that the bacterial structure in samples incubated at 35 °C correlated with temperature and soil respiration, while structures in samples incubated at 15 and 20 °C correlated with time. These results suggest that a temperature rise could result in increasing soil respiration and soluble carbon and nitrogen consumption as well as differentially influence bacterial diversity and structure at different elevations.

scholarly journals Time and Temperature Dependent Changes of Platelet Aggregation

1977 ◽  
Author(s):  
K. Breddin ◽  
H.J. Krzywanek
Keyword(s):  
Platelet Aggregation ◽  
Incubation Temperature ◽  
Inhibitory Effect ◽  
Blood Sampling ◽  
Time Interval ◽  
Temperature Dependent ◽  
Aggregation Pattern ◽  
And Performance ◽  
Incubation Temperatures ◽  
Induced Aggregation

ADP-, collagen and epinephrine-induced aggregation change markedly if citrate blood or PRP are kept at different incubation temperatures or/and if the time interval between blood sampling and testing varies. With a growing time interval the response of PRP to ADP, collagen or epinephrine increases. Desaggregation after ADP-aggregation decreases with time. If PRP is incubated at 4°C or 10°C aggregation is increased in comparison with room temperature. At 37°C aggregation is markedly inhibited. This inhibitory effect is almost fully reversible several hours after blood sampling. Corresponding results were obtained with PAT III, measuring spontaneous aggregation tendency. Morphologic platelet changes show some correlation with the time and temperature dependent changes of the aggregation pattern. In clinical studies the time interval between blood sampling and testing and the incubation temperature of PRP should be strictly controlled. If enhanced platelet aggregation is to be studied the time interval between venepuncture and performance of the test should be 30 - 60 min for ADP-or collagen-induced aggregation and between 90 and 360 min for PAT III. PRP should always be kept at 20 - 25°C.

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