The effect of light and darkness on the production of cercariae of Schistosoma haematobium from Bulinus globosus

1987 ◽  
Vol 61 (4) ◽  
pp. 291-296 ◽  
Author(s):  
K. M. Raymond ◽  
A. J. Probert
Keyword(s):  
Schistosoma Haematobium ◽  
Continuous Illumination ◽  
Light Conditions ◽  
Dark Treatment ◽  
Bulinus Globosus ◽  
Normal Light ◽  
Peak Emission ◽  
Evening Peak ◽  
Second Peak ◽  
Effect Of Light

ABSTRACTThe cercariae of Schistosoma haematobium showed a diurnal periodicity of emergence from Bulinus globosus in a twelve hour light/dark cycle. Peak emission occurred at 11.00 hrs with a smaller peak at 20.00 hrs, following the start of the period of darkness. In continuous illumination this second peak was not seen, indicating that only the morning peak is circadian in origin. The evening peak occurs in response to dark treatment and can be produced by periods of darkness ranging from eight seconds to one hour. The longer the period of dark treatment the longer the rise in output is maintained on return to light conditions. Subjection of snails to periods of dark treatment during the normal light period caused a reduction in the evening peak with the largest effect seen following the longest period of darkness. An increased output of cercariae was seen following fifteen minutes exposure to a range of light intensities, the largest increase occurring at 10 000 and 7000 lux and complete darkness. The rapidity of this reaction to variations in light intensity suggests that the cercariae of S. haematobium are showing emergence in response to shadows.

scholarly journals Mastomys natalensis (Smith, 1834) as a natural host for Schistosoma haematobium (Bilharz, 1852) Weinland, 1858 x Schistosoma bovis Sonsino, 1876 introgressive hybrids

2021 ◽  
Author(s):  
Boris A.E.S. Savassi ◽  
Gauthier Dobigny ◽  
Jonas R. Etougbétché ◽  
Thalasse T. Avocegan ◽  
François T. Quinsou ◽  
...  
Keyword(s):  
Definitive Host ◽  
Schistosoma Haematobium ◽  
Rattus Rattus ◽  
Introgressive Hybridization ◽  
Mastomys Natalensis ◽  
New Host ◽  
Time Period ◽  
Schistosoma Bovis ◽  
Bulinus Globosus ◽  
Internal Transcribed Spacer Rdna

AbstractCercarial emission of schistosomes is a determinant in the transmission to the definitive host and constitutes a good marker to identify which definitive host is responsible for transmission, mainly in introgressive hybridization situations. Our goal was to test the hypothesis that micro-mammals play a role in Schistosoma haematobium, S. bovis, and/or S. haematobium x S. bovis transmission. Small mammal sampling was conducted in seven semi-lacustrine villages of southern Benin. Among the 62 animals trapped, 50 individuals were investigated for Schistosoma adults and eggs: 37 Rattus rattus, 3 Rattus norvegicus, 9 Mastomys natalensis, and 1 Crocidura olivieri. Schistosoma adults were found in four R. rattus and two M. natalensis, with a local prevalence reaching 80% and 50%, respectively. Two cercarial chronotypes were found from Bulinus globosus experimentally infected with miracidia extracted from naturally infected M. natalensis: a late diurnal and nocturnal chronotype, and an early diurnal, late diurnal, and nocturnal chronotype. The cytochrome C oxidase subunit I mtDNA gene of the collected schistosomes (adults, miracidia, and cercariae) belonged to the S. bovis clade. Eleven internal transcribed spacer rDNA profiles were found; four belonged to S. bovis and seven to S. haematobium x S. bovis. These molecular results together with the observed multi-peak chronotypes add M. natalensis as a new host implicated in S. haematobium x S. bovis transmission. We discuss the origin of the new chronotypes which have become more complex with the appearance of several peaks in a 24-h day. We also discuss how the new populations of offspring may optimize intra-host ecological niche, host spectrum, and transmission time period.

scholarly journals Effect of light conditions on anatomical and biochemical aspects of somatic and zygotic embryos of hybrid larch (Larix × marschlinsii)

2015 ◽  
Vol 115 (4) ◽  
pp. 605-615 ◽  
Author(s):  
Patrick von Aderkas ◽  
Caroline Teyssier ◽  
Jean-Paul Charpentier ◽  
Markus Gutmann ◽  
Luc Pâques ◽  
...  
Keyword(s):  
Zygotic Embryos ◽  
Light Conditions ◽  
Hybrid Larch ◽  
Effect Of Light

The effect of soil temperature and light on sprouting and rooting of root cuttings of hybrid aspen clones

2005 ◽  
Vol 35 (11) ◽  
pp. 2671-2678 ◽  
Author(s):  
N Stenvall ◽  
T Haapala ◽  
S Aarlahti ◽  
P Pulkkinen
Keyword(s):  
Soil Temperature ◽  
Populus Tremuloides ◽  
Hybrid Aspen ◽  
Light Conditions ◽  
Dark Treatment ◽  
Sand Mixture ◽  
Negative Effect ◽  
Soil Temperatures ◽  
Time Required ◽  
Better Than

Root cuttings from five clones of hybrid aspen (Populus tremula L. × Populus tremuloides Michx.) obtained from 2-year-old stock plants were grown in a peat–sand mixture (soil) at four soil temperatures (18, 22, 26, and 30 °C). Half of the cuttings were grown in light and the rest in darkness. The root cuttings that were grown at the highest soil temperature sprouted and rooted significantly better than the cuttings grown at the lower temperatures. Light did not affect the sprouting of root cuttings but did have a negative effect on their rooting. Moreover, the clones varied significantly in sprouting and rooting percentages, as well as in the time required for sprouting. In general, higher soil temperatures hastened sprouting of the cuttings. Sprouting was also faster in the light than in the dark treatment. Differences in soil temperature, light conditions, or clone had no significant effect on rooting time.

scholarly journals Simulation of population dynamics of Bulinus globosus: Effects of environmental temperature on production of Schistosoma haematobium cercariae

2018 ◽  
Vol 12 (8) ◽  
pp. e0006651 ◽  
Author(s):  
Chester Kalinda ◽  
Moses J. Chimbari ◽  
William E. Grant ◽  
Hsiao-Hsuan Wang ◽  
Julius N. Odhiambo ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Schistosoma Haematobium ◽  
Environmental Temperature ◽  
Bulinus Globosus

scholarly journals Performance of Iris variegata genotypes in different light conditions: Flowering phenology and reproductive output

Genetika ◽  
2015 ◽  
Vol 47 (2) ◽  
pp. 679-694 ◽  
Author(s):  
Uros Zivkovic ◽  
Danijela Miljkovic ◽  
Natasa Barisic-Klisaric ◽  
Aleksej Tarasjev ◽  
Stevan Avramov
Keyword(s):  
Reproductive Output ◽  
Seed Mass ◽  
Flowering Phenology ◽  
Light Treatment ◽  
Biological Research ◽  
Congeneric Species ◽  
Light Conditions ◽  
Flowering Pattern ◽  
Experimental Garden ◽  
Effect Of Light

We analyzed genetic variability and phenotypic plasticity of flowering pattern and reproductive success in 97 clonal genotypes of Iris variegata originating from contrasting light habitats in Deliblato Sands and expressed under different experimental light conditions. Rhizome segments were taken from each of these clones and transplanted in the experimental garden near the Institute for Biological Research in Belgrade. Significant differences between genotypes were found for two traits (start of flowering, average flowering time). Genotypes originating from open and understory habitats significantly differed for three traits (number of flowers, number of capsules/number of flowers, seed mass/capsule). Significant effect of light treatment were found for three traits (number of capsules/number of flowers, seed mass/capsule, average seed mass). Statistically significant correlations between explored traits were generally similar but also to some extent habitat and treatment specific. Comparing these results with research carried out on congeneric species we noted that there are similar responses for some traits, but also significant differences in some components of flowering and fruiting success.

scholarly journals Effect of Mass Chemotherapy and Piped Water on Numbers of Schistosoma Haematobium and Prevalence in Bulinus Globosus in Kwale, Kenya

1988 ◽  
Vol 38 (3) ◽  
pp. 487-495 ◽  
Author(s):  
Shinichi Noda ◽  
Yoshiki Aoki ◽  
Atsuo Sato ◽  
Ngethe D. Muhoho ◽  
John H. Ouma ◽  
...  
Keyword(s):  
Schistosoma Haematobium ◽  
Piped Water ◽  
Bulinus Globosus

scholarly journals The effect of light factor on the development of thallus and generative organs in Chara vulgaris L.

2014 ◽  
Vol 49 (4) ◽  
pp. 397-407 ◽  
Author(s):  
Janusz Maszewski
Keyword(s):  
Mitotic Activity ◽  
Axenic Culture ◽  
Light Period ◽  
Continuous Illumination ◽  
Chara Vulgaris ◽  
The Moment ◽  
Almost All ◽  
Effect Of Light ◽  
Generative Organs

During long-term axenic culture of Chara continuous illumination (L=24) increases mitotic activity of almost all types of cells. In such conditions only initiation of oogonia is inhibited, leading into a strong predomination of male generative organs. Prolonged darkness (L:D=1:23) exerts a mitodepressing effect. Oogonia and antheridia are especially susceptible to the reduction of the light period. Modifications of the elongating growth in various photoperiods are different in the polyploid regions of the vegetative thallus and in haploid cells of the antheridial filaments. Segments of both axial internodes and lateral pleuridia increase their dimensions at L:D=1:23, whereas at L=24 their growth is significantly inhibited. Different reaction is noted in the cells of antheridial filaments: at L=24 they are about 10% longer than in the control (L:D=14:10). The duration of the antheridium aevelopment, from the stage of unicellular filaments to the moment of antheridium opening, is 1.5 days shorter at L=24 as compared with the control. This shortening includes proportionally both the period of divisions within antheridial filaments and the period of spermatozoid differentiation.

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