scholarly journals Transmission of Cyclocoelum mutabile (Digenea) to snails: the influence of temperature on the egg and miracidium

1994 ◽  
Vol 72 (10) ◽  
pp. 1745-1751 ◽  
Author(s):  
Christopher W. McKindsey ◽  
J. Daniel McLaughlin

This study examined the survival and hatching dynamics of eggs of the digenean Cyclocoelum mutabile and the survivorship and infectivity of the miracidia under different temperature regimes. Hatching did not occur at or below 12 °C. Hatching success was similar at 14, 16, and 20 °C (69–73%). Two peaks in hatching were seen. Most eggs hatched within 12 h following immersion in water; a smaller hatching peak occurred about 24 h later. Storing eggs at 12 °C for up to 4 weeks prior to raising the incubation temperature to 14 °C had no effect on hatching success. However, hatching success was dependent on the source of the eggs. Between 62 and 71% of the eggs from faeces and 90–98% of the eggs dissected from flukes hatched under the same protocol. Miracidia hatching from eggs stored for 0–7 weeks at 7 °C prior to hatching at 14 °C did not differ in their infectivity to snails (75–86%). The survivorship of miracidia was higher at lower temperatures and when they were obtained from eggs dissected from the fluke. The longer survival and prolonged infectivity of miracidia at lower temperatures produced the highest transmission efficiency at 14 °C. These results are discussed in relation to the seasonal transmission and ecology of the fluke.

Zygote ◽  
2019 ◽  
Vol 28 (1) ◽  
pp. 80-82
Author(s):  
Raoani Cruz Mendonça ◽  
Sarah Pittigliani Ikebata ◽  
Sérgio Leandro Araújo-Silva ◽  
João Vitor Azevedo Manhães ◽  
Mônica Yumi Tsuzuki

SummaryThe flameback pygmy angelfish Centropyge aurantonotus, highly appreciated and valued by the aquarium market, is heavily harvested and traded. Temperature is one of the abiotic factors that has the most influence on fish development, especially in the early stages of life. For captive production, it is essential to know the appropriate environmental parameters for each species. In this sense, this study aimed to evaluate the influence of temperature on the embryonic development and hatching rates of C. aurantonotus incubated at six different temperatures (20, 22, 24, 26, 28, 30°C). Embryonic development events were very similar in terms of morphological and chronological characteristics compared with other species of the genus Centropyge. Incubation time was inversely proportional to temperature. The treatment at 22°C required twice the time of that required by 30°C treatment for hatching to occur. The best incubation temperature range was 24–28°C. Values below 22°C and at 30°C showed lower hatching rates compared with other treatments. Based on these results, the recommended temperature at which to incubate C. aurantonotus eggs is between 24–28°C.


1991 ◽  
Vol 26 (1) ◽  
pp. 33-38 ◽  
Author(s):  
T. David Reed ◽  
Paul J. Semtner

Tests were conducted at seven constant temperature regimes in controlled environmental chambers to compare population growth parameters of red and green morphs of the tobacco aphid, Myzus nicotianae Blackman. The optimal temperature for population development of both color morphs was 25°C. At 25°C and above, the red morph had three advantages over the green; most striking was the ability to survive to reproductive age. The red morph also developed faster and was more fecund than the green. Although neither morph reproduced at 32°C, longevity of the red morph was 120% greater. Results of this study may help to explain the disproportionate development of populations of the red morph in the field.


1974 ◽  
Vol 54 (4) ◽  
pp. 725-730 ◽  
Author(s):  
DALE SMITH

Oats (Avena sativa L. cv. Froker) were grown to initial panicle emergence in three day/night temperature regimes; H (32/26 C), W (27/21 C), and C (21/15 C). At initial panicle emergence, some plants were transferred to the other regimes until complete panicle emergence. Plants grown continuously in the W regime reached initial panicle emergence in 34 days and complete panicle emergence in 42 days. These stages were reached about a week later in C regime and about 2 wk later in H regime. As compared with plants retained at one temperature to complete panicle emergence, moving plants at initial panicle emergence from H to W or C, or from C to H or W, decreased time to complete panicle emergence by 4 to 6 days. However, complete panicle emergence was delayed 4 to 5 days when plants were moved from W to C or H. Dry matter yields and growth rates (mg/pot/day) of plants grown continuously in the same regime to initial and to complete panicle emergence were highest, and similar, in the W and C regimes, but were significantly lower in the H. As compared with plants retained at one temperature to complete panicle emergence, changing at initial panicle emergence from H to W or C increased dry matter yields and growth rates at complete panicle emergence, whereas changing from W or C to H decreased these parameters. Yields and growth were changed very little by change from W to C or from C to W.


1978 ◽  
Vol 58 (4) ◽  
pp. 1095-1097 ◽  
Author(s):  
D. M. NAIK ◽  
L. V. BUSCH ◽  
G. L. BARRON

Five strains of Fusarium graminearum isolated from maize in Ontario were evaluated for zearalenone production relative to incubation temperature. All strains produced significant amounts of zearalenone at 25 °C. Toxin production was enhanced by temperature stress (reducing the incubation temperature to 10 °C following a period of growth at 25 °C) in only one of the strains tested.


Author(s):  
Abdulrahman A. Al-Soqeer ◽  
Abdulaziz A. Alqarawi ◽  
Mohamed I. Motawei ◽  
Soleman M. Al-Otayk

Buffelgrass (Cenchrus ciliaris) is widely grown in tropical and sub-tropical arid rangelands around the globe because of its high tolerance to drought and high level of nutrients. In the present study, the seed germination response of 12 buffelgrass genotypes (nine collected accessions and three introduced varieties) was tested to record the various effects of storage duration and temperature treatments on germination. Five constant temperature treatments (15, 20, 25, 30 and 35°C) and two storage durations (12 and 24 months) were used. The studied buffelgrass genotypes responded differently to the different storage durations and temperature regimes, suggesting the importance of genotype assessment under different environments. The highest germination percentages were recorded for genotype BUR-1 at 20°C (45%) after 12 months. No germination occurred after 12 months at low constant temperatures (15°C) for all genotypes except BUR-1, BUR-2 and UIA. Therefore, there is a large genetic variability among buffelgrass genotypes for seed germination, which could permit improvement by selection and breeding.


1986 ◽  
Vol 66 (2) ◽  
pp. 221-227 ◽  
Author(s):  
ZHEGONG FAN ◽  
B. R. STEFANSSON

The effect of temperature on two cytoplasmic male-sterility (CMS) systems in rape (Brassica napus L.) was investigated. These were the nap CMS system with cytoplasm which occurs in most Canadian cultivars and the pol CMS system with cytoplasm from the cultivar Polima. The day/night temperature regimes used were 22/16, 26/20 and 30/24 °C. Two floral characteristics, anther type and stamen length, were influenced by temperature treatments. Male sterility of both CMS systems was expressed consistently at the lowest temperature. The nap male-sterile plants became partially sterile at the second temperature and fully fertile at the highest temperature. The pol male-sterile plants were more stable and became partially sterile only at the highest temperature.Key words: Rape, Brassica napus L., CMS, temperature


Author(s):  
T. Geipel ◽  
W. Mader ◽  
P. Pirouz

Temperature affects both elastic and inelastic scattering of electrons in a crystal. The Debye-Waller factor, B, describes the influence of temperature on the elastic scattering of electrons, whereas the imaginary part of the (complex) atomic form factor, fc = fr + ifi, describes the influence of temperature on the inelastic scattering of electrons (i.e. absorption). In HRTEM simulations, two possible ways to include absorption are: (i) an approximate method in which absorption is described by a phenomenological constant, μ, i.e. fi; - μfr, with the real part of the atomic form factor, fr, obtained from Hartree-Fock calculations, (ii) a more accurate method in which the absorptive components, fi of the atomic form factor are explicitly calculated. In this contribution, the inclusion of both the Debye-Waller factor and absorption on HRTEM images of a (Oll)-oriented GaAs crystal are presented (using the EMS software.Fig. 1 shows the the amplitudes and phases of the dominant 111 beams as a function of the specimen thickness, t, for the cases when μ = 0 (i.e. no absorption, solid line) and μ = 0.1 (with absorption, dashed line).


2010 ◽  
Vol 25 (1) ◽  
pp. 93-105 ◽  
Author(s):  
Daniel Żarski ◽  
Dariusz Kucharczyk ◽  
Wojciech Sasinowski ◽  
Katarzyna Targońska ◽  
Andrzej Mamcarz

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