Responses of miracidia of Schistosoma mansoni to an equal energy spectrum of monochromatic light

1974 ◽  
Vol 52 (7) ◽  
pp. 857-859 ◽  
Author(s):  
D. G. S. Wright
Keyword(s):  
Energy Spectrum ◽  
Schistosoma Mansoni ◽  
Fresh Water ◽  
Monochromatic Light ◽  
Spectral Intensity ◽  
Percentage Composition ◽  
Light Irradiance ◽  
Equal Energy

An equal energy spectrum of monochromatic light (irradiance = 0.22 μW/cm2) caused miracidia of Schistosoma mansoni to respond maximally in a directed manner to wavelengths of 525 nm and 650 um. Miracidia of S. mansoni responded to wavelengths which make up the greatest percentage composition of spectral intensity in clear fresh water and muddy waters.

Responses of cercariae of Trichobilharzia ocellata to white light, monochromatic light, and irradiance reduction

1974 ◽  
Vol 52 (5) ◽  
pp. 575-579 ◽  
Author(s):  
D. G. S. Wright
Keyword(s):  
Energy Spectrum ◽  
White Light ◽  
Monochromatic Light ◽  
Light Irradiance ◽  
Equal Energy ◽  
Illuminance Level ◽  
Trichobilharzia Ocellata

Cercariae of Trichobilharzia ocellata exhibited a significant directed response to white light starting at an illuminance level of 0.35 lx. When exposed to an equal energy spectrum of monochromatic light (irradiance = 0.22 μW/cm2), the most significant directed response occurred at 500 nm. Swimming in response to illuminance reduction varies inversely as the preadaptation irradiance levels.

Responses of miracidia of Schistosomatium douthitti (Cort 1914) to monochromatic light

1972 ◽  
Vol 50 (2) ◽  
pp. 197-200 ◽  
Author(s):  
D. G. S. Wright ◽  
D. M. Lavigne ◽  
K. Ronald
Keyword(s):  
Energy Spectrum ◽  
Monochromatic Light ◽  
Equal Energy

When exposed to an equal energy spectrum (irradiance = 0.225 W/m2) from 450–650 nm miracidia of Schistosomatium douthitti exhibited a significant directed response to monochromatic light at 500 and 525 nm.

scholarly journals The Spectral Sensitivity of Crayfish and Lobster Vision

1961 ◽  
Vol 44 (6) ◽  
pp. 1089-1102 ◽  
Author(s):  
Donald Kennedy ◽  
Merle S. Bruno
Keyword(s):  
Fresh Water ◽  
Spectral Sensitivity ◽  
Light Adaptation ◽  
Compound Eye ◽  
Monochromatic Light ◽  
Sensitivity Function ◽  
Visual Sensitivity ◽  
Long Wavelength ◽  
Cone Pigments ◽  
Sensitivity Data

(1) The spectral sensitivity function for the compound eye of the crayfish has been determined by recording the retinal action potentials elicited by monochromatic stimuli. Its peak lies at approximately 570 mµ. (2) Similar measurements made on lobster eyes yield functions with maxima in the region of 520 to 525 mµ, which agree well with the absorption spectrum of lobster rhodopsin if minor allowances are made for distortion by known screening pigments. (3) The crayfish sensitivity function, since it is unaffected by selective monochromatic light adaptation, must be determined by a single photosensitive pigment. The absorption maximum of this pigment may be inferred with reasonable accuracy from the sensitivity data. (4) The visual pigment of the crayfish thus has its maximum absorption displaced by 50 to 60 mµ towards the red end of the spectrum from that of the lobster and other marine crustacea. This shift parallels that found in both rod and cone pigments between fresh water and marine vertebrates. In the crayfish, however, an altered protein is responsible for the shift and not a new carotenoid chromophore as in the vertebrates. (5) The existence of this situation in a new group of animals (with photoreceptors which have been evolved independently from those of vertebrates) strengthens the view that there may be strong selection for long wavelength visual sensitivity in fresh water.

Better drugs for schistosomiasis

1982 ◽  
Vol 20 (25) ◽  
pp. 98-99
Keyword(s):  
Schistosoma Mansoni ◽  
Intermediate Host ◽  
Fresh Water ◽  
Hepatic Fibrosis ◽  
Tropical Africa ◽  
Confusional State ◽  
Irrigation Systems ◽  
The Brain

Schistosomiasis is becoming more prevalent, especially in tropical Africa, where new irrigation systems are being built in which fresh water snails, the intermediate host of the disease, can thrive. In most areas measures to control the snails have proved unsatisfactory and expensive. Treatment of infected individuals has also been unsatisfactory: the antimonial preparations, niridazole (Ambilhar) and hycanthone (Etrenol)1,2 may be effective but are certainly toxic. Infection (mainly of the intestine) with Schistosoma mansoni and S.japonicum may also lead to hepatic fibrosis with porto-systemic shunting. This further complicates therapy as niridazole, the most widely used drug, cannot be used because the unmetabolised compound reaches the brain and causes a confusional state or psychosis.3

scholarly journals A Cross Sectional Assessment on Distribution of Snail and Risk Factors of Schistosoma Mansoni Infection in Proximity to Water Contact Points in Gorgora Town, Western Dembia District, Northwest Ethiopia.

2020 ◽  
Author(s):  
Aberham Abere ◽  
Ligabaw Worku ◽  
Abebe Genetu ◽  
Dessie Abebaw ◽  
Adane Derso ◽  
...  
Keyword(s):  
Risk Factors ◽  
Schistosoma Mansoni ◽  
Fresh Water ◽  
Health Problem ◽  
Northwest Ethiopia ◽  
Schistosome Infection ◽  
Biomphalaria Pfeifferi ◽  
Water Contact ◽  
Cross Sectional ◽  
Contact Points

Abstract Background: Schistosomiasis is one of the great neglected tropical diseases with socio-economic and health problem worldwide. In Ethiopia numerous studies reported S. mansoni is high among school-age and preschool age children. Though intensive prevalence studies are conducted the snail distribution and infectivity status and human infection rate dynamics in Ethiopian context remains poorly understood. Thus the purpose of the current study was to assess distribution of snail and risk factors of Schistosoma mansoni infection in proximity to water contact points in Gorgora town, Western Dembia District, Northwest Ethiopia. Method: A Community based cross-sectional study was conducted in Gorgora Town from March to May 2020. A total of 385 study participants were selected by systematic random sampling technique. Stool sample was collected and examined by Kato-Katz technique. Malacological survey was done from sampling sites showing signs of human activity near Lake Tana shoreline. Live snails collected in plastic bucket containing water and weed were transported within four hours to the University of Gondar, Medical parasitology laboratory for identification and determination of infection. Data was entered with EPI Data version 4.4.2.1. Data analysis was carried out using SPSS version 20.0 and STATA version 15.0. p-value ≤ 0.05 was reported as statistically significant. Spatial distribution analysis was done using ArcGIS system for Geographical Information System (GIS). Result: The overall prevalence of S. mansoni infection was 36.6% (CI: 32-41.9) with intensity of 30.5%, 27.0% and 42.6% for light, moderate, and heavy, respectively. Among the different fresh water snails collected on the basis of shell morphology 546(%) were Biomphalaria pfeifferi, 310(28.1%) were Bulinus spp, 101(9.1%) were Lymnaea, and 147(13.3%) were Bivalve. Schistosome infection in Biomphalaria spp. was 0.0%. Swimming frequency and proximity to water body were observed to be the most associated risk factor to S. mansoni infection. Conclusion: The study showed that S. mansoni is an ongoing health problem in Gorgora. Different fresh water snails with a potential of transmitting diseases of human and veterinary importance that requires attention had been identified. Longitudinal and molecular study on Biomphalaria pfeifferi infection rate as well as susceptibility to schistosome infection is recommended.

scholarly journals Study on Zooplankton Diversity in A Fresh Water Pond (Raja Bandh) of Jamtara, Jharkhand, India

2021 ◽  
Vol 4 (2) ◽  
Author(s):  
Seema Singh ◽  
Veena Kumari ◽  
Erum Usmani ◽  
Riya Dutta ◽  
Rinki Kumari ◽  
...  
Keyword(s):  
Water Quality ◽  
Population Density ◽  
Quality Assessment ◽  
Fresh Water ◽  
Water Quality Assessment ◽  
Dominant Group ◽  
Percentage Composition ◽  
Ecological Parameter ◽  
Water Pond ◽  
One Year

Zooplankton are cosmopolitan in nature and one of the most important ecological parameter in water quality assessment because they help in disposal of sewage and act as natural purifiers of water. Present study was carried out for a period of one-year from July 2018 to June 2019. The present study deals with Zooplankton diversity throughout the year in raja Bandh Pond of Jamtara, Jharkhand. The diversity of various types of zooplankton was studied and the result revealed that the zooplankton was represented by various genera viz., rotifera, cladocera, copepoda and ostracoda. Present study revealed 14 different species of zooplanktons belonging to 4 different classes namely 5 rotifers, 4 cladocerans, 3 copepods and 2 ostracod was observed. Rotifers were the dominant group of Zooplankton recorded with respect to diversity and population density status. Rotifers and Copepoda were the most dominant during summer than followed by Cladocerans and ostracodes. Present study revealed that the annual percentage composition comprises of 38 % rotifer, 26 % copepod, 20 %, cladocera and 16 % ostracoda respectively. Certain species viz, Brachionus sp, Daphnia sp, Cyclops sp, Cypris sp were recorded throughout the year.

Instrumentation for detecting channelling radiation in the high-voltage electron microscope

1983 ◽  
Vol 41 ◽  
pp. 318-319
Author(s):  
J. H. Butler ◽  
C. J. Humphreys
Keyword(s):  
Monochromatic Light ◽  
Incident Beam ◽  
Laboratory Frame ◽  
Relativistic Electrons ◽  
Voltage Electron ◽  
Dipole Emission ◽  
Sinusoidal Oscillations ◽  
Pass Through ◽  
Incident Beam Energy ◽  
Increasing Function

Electromagnetic radiation is emitted when fast (relativistic) electrons pass through crystal targets which are oriented in a preferential (channelling) direction with respect to the incident beam. In the classical sense, the electrons perform sinusoidal oscillations as they propagate through the crystal (as illustrated in Fig. 1 for the case of planar channelling). When viewed in the electron rest frame, this motion, a result of successive Bragg reflections, gives rise to familiar dipole emission. In the laboratory frame, the radiation is seen to be of a higher energy (because of the Doppler shift) and is also compressed into a narrower cone of emission (due to the relativistic “searchlight” effect). The energy and yield of this monochromatic light is a continuously increasing function of the incident beam energy and, for beam energies of 1 MeV and higher, it occurs in the x-ray and γ-ray regions of the spectrum. Consequently, much interest has been expressed in regard to the use of this phenomenon as the basis for fabricating a coherent, tunable radiation source.

Ultrastructural analysis of “Sensory” surface nerve endings and “putative” neurotransmitter sites in Schistosoma mansoni Miracidia

1989 ◽  
Vol 47 ◽  
pp. 962-963
Author(s):  
Betty Ruth Jones ◽  
Steve Chi-Tang Pan
Keyword(s):  
Nervous System ◽  
Life Cycle ◽  
Schistosoma Mansoni ◽  
Snail Host ◽  
Complex Life Cycle ◽  
Rational Approach ◽  
Effective Control ◽  
The Social ◽  
Social And Economic Development ◽  
Basic Biology

INTRODUCTION: Schistosomiasis has been described as “one of the most devastating diseases of mankind, second only to malaria in its deleterious effects on the social and economic development of populations in many warm areas of the world.” The disease is worldwide and is probably spreading faster and becoming more intense than the overall research efforts designed to provide the basis for countering it. Moreover, there are indications that the development of water resources and the demands for increasing cultivation and food in developing countries may prevent adequate control of the disease and thus the number of infections are increasing.Our knowledge of the basic biology of the parasites causing the disease is far from adequate. Such knowledge is essential if we are to develop a rational approach to the effective control of human schistosomiasis. The miracidium is the first infective stage in the complex life cycle of schistosomes. The future of the entire life cycle depends on the capacity and ability of this organism to locate and enter a suitable snail host for further development, Little is known about the nervous system of the miracidium of Schistosoma mansoni and of other trematodes. Studies indicate that miracidia contain a well developed and complex nervous system that may aid the larvae in locating and entering a susceptible snail host (Wilson, 1970; Brooker, 1972; Chernin, 1974; Pan, 1980; Mehlhorn, 1988; and Jones, 1987-1988).

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