Comparison under controlled conditions of the life cycle of Lepeophtheirus mugiloidis and Caligus rogercresseyi , parasites of the Patagonian blenny Eleginops maclovinus

2021 ◽  
Author(s):  
Sandra Bravo ◽  
Francisca Erranz ◽  
María Teresa Silva
Keyword(s):  
Life Cycle ◽  
Eleginops Maclovinus ◽  
Controlled Conditions

Laboratory comparison of the relative success of Biomphalaria glabrata stocks which are susceptible and insusceptible to infection with Schistosoma mansoni

Parasitology ◽  
1983 ◽  
Vol 86 (2) ◽  
pp. 335-344 ◽  
Author(s):  
D. J. Minchella ◽  
P. T. Loverde
Keyword(s):  
Life Cycle ◽  
Natural Selection ◽  
Reproductive Success ◽  
Natural Populations ◽  
Biomphalaria Glabrata ◽  
Selective Advantage ◽  
Controlled Conditions ◽  
Plausible Answer ◽  
Major Objection ◽  
Transmit Disease

SUMMARYA method of interrupting the life-cycle of the human blood fluke Schistosoma by increasing the proportion of genetically insusceptible intermediate host snails in natural populations was first proposed nearly 25 years ago. The method assumes that insusceptible snails will be at a selective advantage over susceptible snails when the schistosome parasite is present, and therefore natural selection will act to increase the proportion of alleles for insusceptibility. A major objection to the proposed technique is ‘If insusceptible snails are at a selective advantage, then why are they not predominant in natural populations that transmit disease?’ One explanation of this paradox is that insusceptibility may be associated with a disadvantageous character or a physiological defect. This study tests this hypothesis by measuring the relative reproductive success of susceptible and insusceptible snails under controlled conditions. Results indicate that insusceptible (unsuitable) snails are negatively affected in the presence of either susceptible snails or schistosome parasites. Furthermore, in the presence of both susceptible snails and schistosome parasites, insusceptible snails are selectively disadvantaged compared to susceptible snails. These results obtained under laboratory-controlled conditions suggest a plausible answer as to why insusceptible snails are not predominant in natural populations that transmit disease.

scholarly journals Amblyomma rotundatum (Koch, 1844) (Acari: Ixodidae) two-host life-cycle on Viperidae snakes

2010 ◽  
Vol 19 (3) ◽  
pp. 174-178 ◽  
Author(s):  
Daniel Sobreira Rodrigues ◽  
Ricardo Maciel ◽  
Lucas Maciel Cunha ◽  
Romário Cerqueira Leite ◽  
Paulo Roberto de Oliveira
Keyword(s):  
Life Cycle ◽  
North America ◽  
Relative Humidity ◽  
Total Duration ◽  
Ixodid Tick ◽  
Natural Conditions ◽  
South Central ◽  
Controlled Conditions ◽  
In Captivity ◽  
Host Life

Amblyomma rotundatum is an ixodid tick that infests ectothermic animals and reproduces exclusively by parthenogenesis. This tick has been frequently reported to infest reptiles and amphibians, under natural conditions and sometimes in captivity. It was described in Brazil and several other countries of South, Central and North America. Although many studies have reported aspects of its biology, none of them has used regularly either ophidian as hosts, or controlled temperature, humidity and luminosity for parasitic stages. The objective of this experiment was to study the life cycle of A. rotundatum feeding on Viperidae snakes under room controlled conditions at 27 ± 1 ºC temperature, 85 ± 10% relative humidity and 12:12 hours photoperiod for parasitic stages, and under B.O.D incubator conditions at 27 ± 1 ºC temperature, 85 ± 10% relative humidity and scotophase for non-parasitic stages. The total duration of the life cycle ranged from 56 to 163 days (mean of 105 days). Two-host life cycle was observed for most of the ixodid population studied.

Assessment of infection and sporulation processes of Puccinia menthae on peppermint in controlled conditions

1998 ◽  
Vol 49 (7) ◽  
pp. 1125 ◽  
Author(s):  
J. Edwards ◽  
D. G. Parbery ◽  
P. A. Taylor ◽  
G. M. Halloran
Keyword(s):  
Life Cycle ◽  
Environmental Factors ◽  
Latent Period ◽  
Cold Treatment ◽  
Mentha Piperita ◽  
Leaf Wetness ◽  
Controlled Conditions ◽  
Wide Range ◽  
Maximum Temperatures

The effects of environmental factors on components of the life cycle of Puccinia menthae on Mentha × piperita cv. Tod’s Mitcham were examined. Urediniospore germination required at least 6 h leaf wetness and lasted 4-6 h at temperatures of 5-25ºC. Appressoria, substomatal vesicles, and haustoria were produced 6, 6, and 24 h after inoculation, respectively, at 20ºC. The latent period of infection ranged from 50 days at 5ºC to 10 days at 22ºC. Sporulation occurred over a wide range of temperatures (5-27ºC), the optimum being 15-20ºC. The minimum, optimum, and maximum temperatures for infection were <5, 20, and 27ºC, respectively. Teliospore formation required a minimum of 9 days of cold treatment (4ºC) and the ratio of teliospores to urediniospores produced was inversely proportional to the duration and intensity of light received.

The life cycle and geographical distribution of the monorchiid Proctotrema bartolii (Digenea) in the clam Darina solenoides from the Patagonian coast, Argentina

2012 ◽  
Vol 87 (4) ◽  
pp. 392-399 ◽  
Author(s):  
C. Gilardoni ◽  
M.C. Carballo ◽  
F. Cremonte
Keyword(s):  
Life Cycle ◽  
South America ◽  
Geographical Distribution ◽  
Natural Environment ◽  
Infection Prevalence ◽  
Intermediate Hosts ◽  
San Jose ◽  
Eleginops Maclovinus ◽  
Magellan Region ◽  
Patagonian Coast

AbstractThe life cycle of Proctotrema bartolii Carballo, Laurenti & Cremonte 2011 (Digenea: Monorchiidae) at Fracasso Beach (the type locality) (42°25′S, 64°07′W), Península Valdés, Argentina, was investigated. This digenean uses the clam Darina solenoides (Mactridae) as both the first and second intermediate hosts in the natural environment. The metacercariae were located mainly at the tip of the incurrent siphon, with an infection prevalence of 100%. Experimental infections in other macroinvertebrates, such as the clam Tellina petitiana and the polychaete Glycera americana, were successful, but these and other invertebrates are not naturally infected. Silversides Odontesthes smitti and Odontesthesnigricans (Pisces: Atherinopsidae) and the mullet Eleginops maclovinus (Eleginopidae) act as the definitive hosts of both experimentally and naturally obtained adults. Fish acquire infection by eating either the siphon or the entire clam. Proctotrema bartolii seems to be endemic to the Magellan Region and is distributed where its intermediate clam host is present, from the San José Gulf in Península Valdés to the southern tip of South America.

scholarly journals Life cycle and reproductive patterns of Triatoma rubrovaria (Blanchard, 1843) (Hemiptera: Reduviidae) under constant and fluctuating conditions of temperature and humidity

2005 ◽  
Vol 38 (5) ◽  
pp. 433-437 ◽  
Author(s):  
Miryam P. Damborsky ◽  
María E. Bar ◽  
David Gorla
Keyword(s):  
Life Cycle ◽  
Adult Development ◽  
Reproductive Performance ◽  
Room Temperature ◽  
Cycle Duration ◽  
Climatic Chamber ◽  
Controlled Conditions ◽  
Temperature And Humidity ◽  
Temperature Group ◽  
Life Cycle Duration

The aim of this study was to evaluate the temperature and relative humidity influence in the life cycle, mortality and fecundity patterns of Triatoma rubrovaria. Four cohorts with 60 recently laid eggs each were conformed. The cohorts were divided into two groups. In the controlled conditions group insects were maintained in a dark climatic chamber under constant temperature and humidity, whereas triatomines of the ambiental temperature group were maintained at room temperature. Average incubation time was 15.6 days in the controlled conditions group and 19.1 days in the ambiental temperature. In group controlled conditions the time from egg to adult development lasted 10 months while group ambiental temperature took four months longer. Egg eclosion rate was 99.1% and 98.3% in controlled conditions and ambiental temperature, respectively. Total nymphal mortality in controlled conditions was 52.6% whereas in ambiental temperature was 51.8%. Mean number of eggs/female was 817.6 controlled conditions and 837.1 ambiental temperature. Fluctuating temperature and humidity promoted changes in the life cycle duration and in the reproductive performance of this species, although not in the species mortality.

Development of a Rapid Survey Method of Sampling and Analysis for Asbestos in Ambient Air

1972 ◽  
Vol 30 ◽  
pp. 630-631 ◽  
Author(s):  
R. E. Heffelfinger ◽  
C. W. Melton ◽  
D. L. Kiefer ◽  
W. M. Henry ◽  
R. J. Thompson
Keyword(s):  
Neutron Activation ◽  
Ambient Air ◽  
Survey Method ◽  
Potential Hazard ◽  
Transmission Microscopy ◽  
Comparative Analyses ◽  
Asbestos Fibers ◽  
Controlled Conditions ◽  
Unequivocal Identification ◽  
Identification And Quantification

A methodology has been developed and demonstrated which is capable of determining total amounts of asbestos fibers and fibrils in air ranging from as low as fractional nanograms per cubic meter (ng/m3) of air to several micrograms/m3. The method involves the collection of samples on an absolute filter and provides an unequivocal identification and quantification of the total asbestos contents including fibrils in the collected samples.The developed method depends on the trituration under controlled conditions to reduce the fibers to fibrils, separation of the asbestos fibrils from other collected air particulates (beneficiation), and the use of transmission microscopy for identification and quantification. Its validity has been tested by comparative analyses by neutron activation techniques. It can supply the data needed to set emissions criteria and to serve as a basis for assessing the potential hazard for asbestos pollution to the populace.

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).

A freeze-fracture-etched study of the physarum polycephalum plasma membrane during early formation of the macroplasmodial stage

1993 ◽  
Vol 51 ◽  
pp. 346-347
Author(s):  
Randolph W. Taylor ◽  
Henrie Treadwell
Keyword(s):  
Plasma Membrane ◽  
Life Cycle ◽  
Growth Phase ◽  
Filter Paper ◽  
Physarum Polycephalum ◽  
Freeze Fracture ◽  
Petri Dish ◽  
Wire Screen ◽  
Wide Mouth ◽  
Sterile Filter

The plasma membrane of the Slime Mold, Physarum polycephalum, process unique morphological distinctions at different stages of the life cycle. Investigations of the plasma membrane of P. polycephalum, particularly, the arrangements of the intramembranous particles has provided useful information concerning possible changes occurring in higher organisms. In this report Freeze-fracture-etched techniques were used to investigate 3 hours post-fusion of the macroplasmodia stage of the P. polycephalum plasma membrane.Microplasmodia of Physarum polycephalum (M3C), axenically maintained, were collected in mid-expotential growth phase by centrifugation. Aliquots of microplasmodia were spread in 3 cm circles with a wide mouth pipette onto sterile filter paper which was supported on a wire screen contained in a petri dish. The cells were starved for 2 hrs at 24°C. After starvation, the cells were feed semidefined medium supplemented with hemin and incubated at 24°C. Three hours after incubation, samples were collected randomly from the petri plates, placed in plancettes and frozen with a propane-nitrogen jet freezer.

Sign in / Sign up

Export Citation Format

Share Document