The influence of centrifugation and incubation temperatures on various veterinary and human chlamydial species

2019 ◽  
Vol 233 ◽  
pp. 11-20 ◽  
Author(s):  
Delia Onorini ◽  
Manuela Donati ◽  
Hanna Marti ◽  
Roberta Biondi ◽  
Aurora Levi ◽  
...  
Keyword(s):  
Chlamydial Species ◽  
Incubation Temperatures

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.

Influence of starter culture type and incubation temperatures on rheology and microstructure of low fat set yoghurt

2009 ◽  
Vol 62 (4) ◽  
pp. 549-555 ◽  
Author(s):  
HABIB ABBASI ◽  
MOHAMMAD EBRAHIMZADEH MOUSAVI ◽  
MOHAMMAD REZA EHSANI ◽  
ZAHRA EMAM d-JOMEA ◽  
MOHARAM VAZIRI ◽  
...  
Keyword(s):  
Starter Culture ◽  
Low Fat ◽  
Incubation Temperatures

scholarly journals Characterization and optimization of extracellular enzymes production by Aspergillus niger strains isolated from date by-products

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Reda Bellaouchi ◽  
Houssam Abouloifa ◽  
Yahya Rokni ◽  
Amina Hasnaoui ◽  
Nabil Ghabbour ◽  
...  
Keyword(s):  
Aspergillus Niger ◽  
Culture Medium ◽  
Extracellular Enzymes ◽  
Enzyme Expression ◽  
Specific Enzyme ◽  
Enzymatic Production ◽  
High Production Rate ◽  
High Production ◽  
Incubation Temperatures ◽  
By Products

Abstract Background This work aims to study the optimal conditions of the fermentation culture medium used for the production of extracellular enzymes (amylase, cellulase, lipase, and protease) from previously isolated Aspergillus niger strains in date by-products. Results The five most powerful isolates selected based on the zone of degradation formed on Petri plates by the substrate were subjected to the quantitative evaluation of their enzymatic production. All five strains showed almost similar API-ZYM profiles, with minor variations observed at the level of some specific enzyme expression. The production of cellulase and amylase was depending on pH and incubation temperatures. ASP2 strain demonstrated the high production rate of amylase (at pH 5 and 30 °C) and cellulase (at pH 6 and 30 °C) for 96 h of incubation. Conclusion The A. niger showed the ability to produce several extracellular enzymes and can be used in the valorization of different agroindustrial residues.

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.

scholarly journals Dual sensor measurement shows that temperature outperforms pH as an early sign of aerobic deterioration in maize silage

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Guilin Shan ◽  
Wolfgang Buescher ◽  
Christian Maack ◽  
André Lipski ◽  
Ismail-Hakki Acir ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Aerobic Metabolism ◽  
Maize Silage ◽  
Aerobic Stability ◽  
Dual Sensor ◽  
Ruminant Diets ◽  
Incubation Temperatures ◽  
Biological Additive ◽  
Real Time Information ◽  
First Time

AbstractHigh quality silage containing abundant lactic acid is a critical component of ruminant diets in many parts of the world. Silage deterioration, a result of aerobic metabolism (including utilization of lactic acid) during storage and feed-out, reduces the nutritional quality of the silage, and its acceptance by animals. In this study, we introduce a novel non-disruptive dual-sensor method that provides near real-time information on silage aerobic stability, and demonstrates for the first time that in situ silage temperature (Tsi) and pH are both associated with preservation of lactic acid. Aerobic deterioration was evaluated using two sources of maize silage, one treated with a biological additive, at incubation temperatures of 23 and 33 °C. Results showed a time delay between the rise of Tsi and that of pH following aerobic exposure at both incubation temperatures. A 11 to 25% loss of lactic acid occurred when Tsi reached 2 °C above ambient. In contrast, by the time the silage pH had exceeded its initial value by 0.5 units, over 60% of the lactic acid had been metabolized. Although pH is often used as a primary indicator of aerobic deterioration of maize silage, it is clear that Tsi was a more sensitive early indicator. However, the extent of the pH increase was an effective indicator of advanced spoilage and loss of lactic acid due to aerobic metabolism for maize silage.

Cereal Callus Cultures: Control of Headspace Gases Can Optimise the Conditions for Callus Proliferation

1992 ◽  
Vol 40 (6) ◽  
pp. 737 ◽  
Author(s):  
SW Adkins
Keyword(s):  
Oryza Sativa L ◽  
Petri Dish ◽  
Triticum Aestivum L ◽  
Callus Cultures ◽  
Gaseous Atmosphere ◽  
Callus Growth ◽  
Culture Vessel ◽  
Rice Callus ◽  
Incubation Temperatures ◽  
Wheat Callus

The protective conditions under which callus cultures are grown to prevent microbial contamination and to reduce tissue desiccation cause the accumulation of volatiles in the vessel headspace and reduce the availability of oxygen for respiration. To demonstrate the importance of the gaseous atmosphere to culture growth a study was undertaken on non-morphogenic rice and wheat callus incubated under a number of environmental conditions. Changes in the gaseous atmosphere above rice (Oryza sativa L.) callus during routine culture in a petri dish suppressed growth and promoted necrosis. Incubating callus under a continuous flow of gas mixtures of known composition suggested that the inhibition of growth was caused by the accumulation of high levels of ethylene and to the rapid depletion of oxygen. In order to evaluate the importance of ethylene accumulation aminoethoxyvinyl glycine (AVG), I-aminocyclopropane-I-carboxylic acid (ACC) and silver nitrate (AgNO3) were added to the nutrient medium and ethylene was measured during callus culture. Ethylene restricted callus growth particularly under high (35°C) compared with moderate (25°C) incubation temperatures and under illuminated compared with dark incubation. Under illuminated incubation at 25°C, AVG ( 5 μM ) and AgNO3 (50 μM) improved rice callus growth by 69 and 54% respectively while ACC (100 μM) decreased growth by 15%. Furthermore, rice callus growth was better in large compared with small culture vessels since ethylene accumulation was reduced. In contrast, wheat (Triticum aestivum L.) callus grew well in the petri dish system and released very little ethylene into the culture vessel headspace. Growth was better under illuminated than darkened conditions and under moderate (25°C) compared with high (35°C) incubation temperatures. Furthermore, wheat callus growth was only marginally better in large compared with small culture vessels. Ethylene was not a restrictive factor of wheat callus growth since only low levels were detected in all conditions of incubation. Better control of ethylene and increased oxygen availability could be a way of increasing cell and tissue production for genetic engineering studies of otherwise recalcitrant species such as rice, and may be a way of improving manipulation of wheat.

Colony initiation in flax rust in axenic culture: involvement of a volatile factor

1979 ◽  
Vol 57 (23) ◽  
pp. 2657-2662 ◽  
Author(s):  
Rosalinda Boasson ◽  
Michael Shaw
Keyword(s):  
Carbon Dioxide ◽  
Axenic Culture ◽  
Conclusive Evidence ◽  
Culture Flask ◽  
Melampsora Lini ◽  
Air Space ◽  
Lag Period ◽  
Axenic Cultures ◽  
Incubation Temperatures

In axenic cultures of flax rust (Melampsora lini) colonies are initiated after a lag period of 12–20 days, depending partly on incubation temperatures. Colony initiation is completely inhibited by removal of a volatile factor which is absorbed by KOH in the air space of the culture flask. The fungus remains sensitive to this inhibition for 8–10 days, i.e., until shortly before visible colonies would normally have developed. While in the presence of KOH, the fungus is not killed; cultures grow normally after removal of the KOH.Although conclusive evidence must await further work, the available data strongly suggest that carbon dioxide is responsible for this effect.

scholarly journals Survival characteristics of Salmonella enterica serovar Enteritidis in chicken egg albumen

2006 ◽  
Vol 134 (5) ◽  
pp. 967-976 ◽  
Author(s):  
H. KANG ◽  
C. LOUI ◽  
R. I. CLAVIJO ◽  
L. W. RILEY ◽  
S. LU
Keyword(s):  
Salmonella Enterica ◽  
Iron Acquisition ◽  
Foodborne Pathogen ◽  
Human Infection ◽  
Salmonella Enterica Serovar Enteritidis ◽  
Factors Affecting ◽  
Chicken Egg ◽  
Egg Albumen ◽  
High Concentrations ◽  
Incubation Temperatures

Salmonella enterica serovar Enteritidis (SE) is a major foodborne pathogen primarily causing human infection through contaminated chicken eggs. To understand how SE survives in chicken egg albumen, we systematically and quantitatively analysed the survival properties of SE in egg albumen and identified factors affecting its survival. Survival assays of SE in egg indicate that egg albumen restricted the growth of SE. A major factor that controlled SE's growth in egg albumen was iron restriction, since egg albumen supplemented with iron allowed SE to grow, and iron acquisition mutants of SE showed decreased survival in egg albumen. In addition, low pH of albumen, high concentrations of bacteria and low incubation temperatures of bacteria with albumen facilitates the survival of SE. Our results suggest that egg albumen uses multiple mechanisms to control SE including iron limitation, surface interaction and possible enzymatic activities.

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.

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