Effects of temperature and humidity on the development of eggs ofToxocara canisunder laboratory conditions

2005 ◽  
Vol 79 (4) ◽  
pp. 327-331 ◽  
Author(s):  
M.I. Gamboa
Keyword(s):  
Elevated Temperatures ◽  
Toxocara Canis ◽  
Soil Samples ◽  
Egg Maturation ◽  
Three Samples ◽  
Temperature And Humidity ◽  
Survival And Development ◽  
Effects Of Temperature ◽  
Increasing Temperature

AbstractThe influence of temperature and humidity on the survival and development ofToxocara caniseggs in anin vitromodel system was investigated. Two soil samples were inoculated withT. caniseggs and maintained at 3% and 50% humidity and temperatures of 19–24°C. Nine soil samples were inoculated withT. caniseggs of which three samples were kept at 4°C with humidities at 3%, 15%, and 30%; three were maintained at 21°C and three more were incubated at 34°C, and at the same three humidity levels. Samples were monitored every 7 days for a total of 2 months, for the presence and development of eggs. With increasing temperature, the number of eggs undergoing development increased (P<0.01); the number of deformed eggs decreased, the number of infective eggs increased (P<0.01), and egg maturation was accelerated. A decrease in the survival of infective eggs occurred at 34°C. An increase in humidity produced a rise in the number of developed eggs at all three temperatures (P<0.01). This study suggests that elevated temperatures accelerated the development as well as the degradation of eggs ofT. canis, whereas the range in humidity was directly correlated with egg development.

Observations on the free-living stages of the stomach worm Haemonchus contortus

Parasitology ◽  
1963 ◽  
Vol 53 (3-4) ◽  
pp. 469-481 ◽  
Author(s):  
J. H. Rose
Keyword(s):  
Haemonchus Contortus ◽  
Free Living ◽  
Rate Of Development ◽  
Temperature And Humidity ◽  
Survival And Development ◽  
Effects Of Temperature ◽  
Eggs And Larvae ◽  
Heavy Mortality

Outdoor observations were made on the rate of development of the free-living stages of H. contortus at different times of the year, and on the migratory activities and longevity of the larvae in faeces, on herbage and in soil.The effects of temperature and humidity on the survival and development of eggs and larvae, both in faeces and when separated from the faeces, were studied in the laboratory.The results of these observations are discussed in relation to the heavy mortality of the free-living stages of H. contortus and to the transmission of infection in the field.

Effects of Temperature and Humidity on the Rust-Red Flour Beetle, Tribolium-Castaneum (Herbst) (Coleoptera, Tenebrionidae), in Wheat-Grain

1987 ◽  
Vol 35 (1) ◽  
pp. 43 ◽  
Author(s):  
GG White
Keyword(s):  
Tribolium Castaneum ◽  
Larval Survival ◽  
Population Increase ◽  
Effect Of Temperature ◽  
Wheat Grain ◽  
Mathematical Functions ◽  
Temperature And Humidity ◽  
Survival And Development ◽  
Effects Of Temperature ◽  
Coleoptera Tenebrionidae

Rates of survival and development of the immature stages of Tribolium castaneum (Herbst) (Coleoptera : Tenebrionidae) were determined in wheat grain at constant temperatures from 20 to 37.5�C and constant relative humidities from 25 to 65%. The rates for eggs and pupae were similar to those previously published for T. castaneum in flour, but larval development was slower and mortality greater, except at low temperature and high humidity. The effect of temperature and humidity on rates of fertility and oviposition in young adults were also determined in wheat grain. The patterns of effects of temperature and humidity on oviposition were similar to those previously published for T. castaneum in flour, but the maximum observed oviposition rate was lower. Fertility was significantly reduced when densities of adults were greater than one pair per 250 g. Mathematical functions were fitted to data from the present and previous studies on age-specific survival and fecundity of adults; population growth rate statistics were calculated from life-table parameters defined by these functions. Under optimal conditions within the range of the present study (35�C, 65% RH), the innate capacity for increase rm was 0.84 per week. The limits for population increase, where rm is zero, were largely determined by.the limits for larval survival, which were approximately 35% RH, and 20-22�C at the lower limit and 40�C at the upper limit.

In vitro studies on the environmental biology of Goiodes colchici (Denny) (Mallophaga : Ischnocera) II. The effects of temperature and humidity on water loss

1970 ◽  
Vol 18 (4) ◽  
pp. 391 ◽  
Author(s):  
RT Williams
Keyword(s):  
Water Loss ◽  
Similar Rate ◽  
Weight Changes ◽  
Environmental Biology ◽  
Efficient Control ◽  
Temperature And Humidity ◽  
Survival And Reproduction ◽  
Effects Of Temperature ◽  
Body Lice

Weight changes have been used to assess the effect of various conditions of temperature and humidity on the rates of water loss of pheasant body lice, G. colchici. Both living and dead animals, in 0% R.H., lose water at a low but increasing rate from 32 to 40C; above this temperature, the rate of water loss suddenly increases. Living insects lose water at half the rate of dead ones over this temperature range. At 35C and 0% R.H., all non-moulting stages lose water at a similar rate. Moulting insects lose water at half the rate of non-moulting ones. The threshold humidity for survival of these insects is within the range 52.5-62.5% R.H. The weight of mature animals does not vary at different humidities above the threshold. In general, the patterns of humidity requirements and regulation of water loss of G. colchici do not differ from those of other insects. There is no evidence that the dependence of these animals on temperatures in the 30-40C range for survival and reproduction is connected with more efficient control of water loss under these conditions.

Effects of Temperature and Humidity on the Germination of Two Pioneer Species in Ecological Restoration

2012 ◽  
Vol 209-211 ◽  
pp. 1265-1268 ◽  
Author(s):  
Di Zhang ◽  
Xi Liu ◽  
Fang Qing Chen
Keyword(s):  
Seed Germination ◽  
Ecological Restoration ◽  
Ecological Engineering ◽  
Treatment Level ◽  
Pioneer Species ◽  
Important Species ◽  
Germination Temperature ◽  
Temperature And Humidity ◽  
Effects Of Temperature ◽  
Increasing Temperature

Seed germination and seedling establishment is a critical stage in the life cycle. Cynodon dactylon and Medicago sativa are two important species using in ecological restoration. Control experiments were employed to test the effects of temperature and humidity on the germination of the two pioneer species. The experiment included three temperature treatment level (15, 20, 25 °C) and four humidity treatment (5, 10, 15, 20 %) with three repeats. Results showed that temperature and humidity had significant effects on the germination of both species seeds. Seed germination of C. dactylon fluctuated with the increasing temperature, but increased with the increasing humidity. The optimal germination temperature and humidity for C. dactylon seeds was 20 °C and 20 % respectively. Seed germination of M. sativa increased with the increasing temperature meanwhile fluctuated with the increasing humidity. The optimal germination temperature and humidity for M. sativa seeds was 25 °C and 10 % respectively. It is critical to provide suitable soil humidity for seed germination in the ecological engineering.

Effects of temperature on slow and fast inactivation of rat skeletal muscle Na+channels

1999 ◽  
Vol 277 (5) ◽  
pp. C937-C947 ◽  
Author(s):  
Robert L. Ruff
Keyword(s):  
Skeletal Muscle ◽  
Potential Temperature ◽  
Resting Potential ◽  
Mammalian Skeletal Muscle ◽  
Slow Inactivation ◽  
Fast Inactivation ◽  
Effects Of Temperature ◽  
Increasing Temperature ◽  
Fast Twitch

Patch-clamp studies of mammalian skeletal muscle Na+ channels are commonly done at subphysiological temperatures, usually room temperature. However, at subphysiological temperatures, most Na+ channels are inactivated at the cell resting potential. This study examined the effects of temperature on fast and slow inactivation of Na+ channels to determine if temperature changed the fraction of Na+ channels that were excitable at resting potential. The loose patch voltage clamp recorded Na+ currents ( I Na) in vitro at 19, 25, 31, and 37°C from the sarcolemma of rat type IIb fast-twitch omohyoid skeletal muscle fibers. Temperature affected the fraction of Na+ channels that were excitable at the resting potential. At 19°C, only 30% of channels were excitable at the resting potential. In contrast, at 37°C, 93% of Na+ channels were excitable at the resting potential. Temperature did not alter the resting potential or the voltage dependencies of activation or fast inactivation. I Na available at the resting potential increased with temperature because the steady-state voltage dependence of slow inactivation shifted in a depolarizing direction with increasing temperature. The membrane potential at which half of the Na+channels were in the slow inactivated state was shifted by +16 mV at 37°C compared with 19°C. Consequently, the low availability of excitable Na+ channels at subphysiological temperatures resulted from channels being in the slow, inactivated state at the resting potential.

Influence of humidity and temperature during exposure on SO2-induced leaf necrosis of Virginia pine and river birch

1987 ◽  
Vol 17 (10) ◽  
pp. 1213-1218 ◽  
Author(s):  
D. M. Umbach ◽  
D. D. Davis
Keyword(s):  
Vapor Pressure ◽  
Vapor Pressure Deficit ◽  
Leaf Conductance ◽  
Negative Slope ◽  
Pine Seedlings ◽  
Temperature And Humidity ◽  
Leaf Necrosis ◽  
Effects Of Temperature ◽  
Increasing Temperature ◽  
The Relationship

River birch and Virginia pine seedlings were exposed to 0.8 or 1.0 ppm SO2 (approximately 2100 and 2600 μg m−3, respectively) for 4 h at temperatures of 16, 24, and 32 °C and at relative humidities of 60, 75, and 90%, in all combinations. Virginia pine seedlings exhibited increased SO2-induced leaf necrosis with increasing temperature and with increasing humidity. For greenhouse-grown Virginia pine seedlings, the relationship between leaf necrosis and vapor pressure deficit was linear with a common negative slope but with different intercepts for each temperature. For Virginia pine seedlings grown outdoors, the relationship between leaf necrosis and vapor pressure deficit was also linear, but both slope and intercept changed with temperature. For river birch, temperature did not greatly affect the overall level of injury; instead, the response to humidity was negligible, linear, or quadratic, depending on temperature and on the conditions under which seedlings were grown. The effects of temperature and humidity on injury to Virginia pine are consistent with an explanation based on changes in leaf conductance; however, such an explanation cannot easily account for the observed response of river birch.

scholarly journals Occurrence and Survival of Livestock-Associated MRSA in Pig Manure and on Agriculture Fields

Antibiotics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 448
Author(s):  
Lӕrke Boye Astrup ◽  
Julie Elvekjӕr Hansen ◽  
Karl Pedersen
Keyword(s):  
Staphylococcus Aureus ◽  
Risk Factor ◽  
Human Exposure ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Soil Samples ◽  
Pig Manure ◽  
Liquid Manure ◽  
Pig Production ◽  
Increasing Temperature

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) is widespread in European pig production, and an increasing number of humans attract infections with this bacterium. Although most infections occur in humans with direct livestock contact, an increasing number of infections occur in humans without any established livestock contact. There have been speculations that at least some of these infections may be connected to the exposure of liquid pig manure for example spread as fertilizers. The present study therefore undertook to measure the presence of LA-MRSA in liquid pig manure and on the surface of soils fertilized with liquid manure and investigate the survival of the bacterium in manure. The results showed that LA-MRSA could be detected in 7 out of 20 liquid manure samples and in 12 out of 186 soil samples. However, the bacterium was not more frequently detected in samples collected after compared to before the spreading of liquid manure on the fields, thus suggesting that other sources of LA-MRSA on agriculture fields likely exist. The decimation time in liquid manure was >32 days at 5 °C in vitro but decreased with increasing temperature. Based on these results, liquid manure does not appear to be an important risk factor for human exposure to LA-MRSA.

A comparison of Toxocara canis embryonation under controlled conditions in soil and hair

2012 ◽  
Vol 87 (1) ◽  
pp. 78-84 ◽  
Author(s):  
J. Devoy Keegan ◽  
C.V. Holland
Keyword(s):  
Direct Contact ◽  
Toxocara Canis ◽  
Soil Samples ◽  
Egg Viability ◽  
Rate Of Development ◽  
Controlled Conditions ◽  
Hair Samples ◽  
Temperature And Humidity ◽  
Two Temperatures ◽  
Paratenic Hosts

AbstractToxocara spp. eggs require a period of time under appropriate environmental conditions to become infective to definitive and paratenic hosts. Temperature and humidity are important factors known to affect the levels of development in soil. We aimed to investigate whether the eggs of T. canis could embryonate in dog hair under controlled conditions of temperature and humidity and, if so, to what degree. No previous work had been carried out on embryonation in hair under controlled conditions. Soil samples exposed to the same conditions as the hair samples were considered a suitable comparison in order to investigate differing levels of development. Development at two temperatures (10°C and 20°C) and the addition of water to samples was investigated over a period of 8 weeks. Importantly, we demonstrated that unembryonated T. canis eggs are capable of development in hair under controlled conditions. The rate of development is lower than that observed in soil, but remains biologically significant in terms of the overall numbers of potentially infective embryonated eggs present. Temperature is responsible for the rate of embryonation while moisture is essential for encouraging development and maintaining egg viability in general. In light of these findings the transmission of Toxocara spp. as a result of direct contact with well-cared-for owned dogs seems unlikely, but should not be ignored.

In vitro studies on the environmental biology of Goiodes colchici (Denny) (Mallophaga : Ischnocera) I. The effects of temperature and humidity on the bionomics of G. colchici

1970 ◽  
Vol 18 (4) ◽  
pp. 379 ◽  
Author(s):  
RT Williams
Keyword(s):  
Egg Production ◽  
Egg Laying ◽  
Adult Longevity ◽  
Environmental Biology ◽  
Chill Coma ◽  
Temperature And Humidity ◽  
Effects Of Temperature ◽  
High Level ◽  
Body Lice

Pheasant body lice, G. colchici, were exposed to various conditions of temperature and humidity, and the consequent variations in adult longevity, egg production, fecundity, and egg resorption recorded. Temperatures in the 30-40C range were found to be essential for normal existence. Above this, animals died within 48 hr. Below this, irrespective of humidity, chill-coma supervened, survival was curtailed, and no eggs were laid. At 30�C, survival was maximal, but few eggs were laid. Due to a high level of fecundity, egg production was maximal at 35C at a high humidity, and survival equalled that at 30C. Levels of fecundity, egg-laying, and survival dropped as the humidity fell, and also as the temperature increased or decreased about 35C. It is evident that survival, fecundity, egg production, and egg-laying are closely geared to temperature and humidity.

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