Parasite life-cycle studies: a plea to resurrect an old parasitological tradition

2017 ◽  
Vol 91 (6) ◽  
pp. 647-656 ◽  
Author(s):  
I. Blasco-Costa ◽  
R. Poulin
Keyword(s):  
Life Cycle ◽  
Large Scale ◽  
Integrative Taxonomy ◽  
Life Cycles ◽  
Intermediate Hosts ◽  
Parasite Life Cycle ◽  
Quantitative Evidence ◽  
Research Areas ◽  
Food Web Ecology ◽  
And Control

AbstractMany helminth taxa have complex life cycles, involving different life stages infecting different host species in a particular order to complete a single generation. Although the broad outlines of these cycles are known for any higher taxon, the details (morphology and biology of juvenile stages, specific identity of intermediate hosts) are generally unknown for particular species. In this review, we first provide quantitative evidence that although new helminth species are described annually at an increasing rate, the parallel effort to elucidate life cycles has become disproportionately smaller over time. We then review the use of morphological matching, experimental infections and genetic matching as approaches to elucidate helminth life cycles. Next we discuss the various research areas or disciplines that could benefit from a solid knowledge of particular life cycles, including integrative taxonomy, the study of parasite evolution, food-web ecology, and the management and control of parasitic diseases. Finally, we end by proposing changes to the requirements for new species descriptions and further large-scale attempts to genetically match adult and juvenile helminth stages in regional faunas, as part of a plea to parasitologists to bring parasite life-cycle studies back into mainstream research.

scholarly journals Advances of 2nd Life Applications for Lithium Ion Batteries from Electric Vehicles Based on Energy Demand

2021 ◽  
Vol 13 (10) ◽  
pp. 5726
Author(s):  
Aleksandra Wewer ◽  
Pinar Bilge ◽  
Franz Dietrich
Keyword(s):  
Life Cycle ◽  
Lithium Ion Batteries ◽  
Electric Vehicles ◽  
Energy Demand ◽  
Lithium Ion ◽  
Life Cycles ◽  
Future Research ◽  
Research Areas ◽  
Study Results ◽  
The Impact

Electromobility is a new approach to the reduction of CO2 emissions and the deceleration of global warming. Its environmental impacts are often compared to traditional mobility solutions based on gasoline or diesel engines. The comparison pertains mostly to the single life cycle of a battery. The impact of multiple life cycles remains an important, and yet unanswered, question. The aim of this paper is to demonstrate advances of 2nd life applications for lithium ion batteries from electric vehicles based on their energy demand. Therefore, it highlights the limitations of a conventional life cycle analysis (LCA) and presents a supplementary method of analysis by providing the design and results of a meta study on the environmental impact of lithium ion batteries. The study focuses on energy demand, and investigates its total impact for different cases considering 2nd life applications such as (C1) material recycling, (C2) repurposing and (C3) reuse. Required reprocessing methods such as remanufacturing of batteries lie at the basis of these 2nd life applications. Batteries are used in their 2nd lives for stationary energy storage (C2, repurpose) and electric vehicles (C3, reuse). The study results confirm that both of these 2nd life applications require less energy than the recycling of batteries at the end of their first life and the production of new batteries. The paper concludes by identifying future research areas in order to generate precise forecasts for 2nd life applications and their industrial dissemination.

scholarly journals Structural, functional and computational studies of membrane recognition by Plasmodium Perforin-Like Proteins 1 and 2.

2021 ◽  
Author(s):  
Sophie Williams ◽  
Xiulian Yu ◽  
Tao Ni ◽  
Robert Gilbert ◽  
Phillip Stansfeld
Keyword(s):  
Life Cycle ◽  
Lipid Bilayers ◽  
Membrane Binding ◽  
Binding Activity ◽  
Life Cycles ◽  
Site Directed Mutagenesis ◽  
Parasite Life Cycle ◽  
Dynamics Simulations ◽  
Membrane Recognition

Perforin-like proteins (PLPs) play key roles in the mechanisms associated with parasitic disease caused by apicomplexans such as Plasmodium (malaria) and Toxoplasma. The T. gondii PLP1 (TgPLP1) mediates tachyzoite egress from cells, while the five Plasmodium PLPs carry out various roles in the life cycle of the parasite and with respect to the molecular basis of disease. Here we focus on Plasmodium vivax PLP1 and PLP2 (PvPLP1 and PvPLP2) compared to TgPLP1; PvPLP1 is important for invasion of mammalian hosts by the parasite and establishment of a chronic infection, PvPLP2 is important during the symptomatic blood stage of the parasite life cycle. Determination of the crystal structure of the membrane-binding APCβ domain of PvPLP1 reveals notable differences with that of TgPLP1, which are reflected in its inability to bind lipid bilayers in the way that TgPLP1 and PvPLP2 can be shown to. Molecular dynamics simulations combined with site-directed mutagenesis and functional assays allow a dissection of the binding interactions of TgPLP1 and PvPLP2 on lipid bilayers, and reveal a similar tropism for lipids found enriched in the inner leaflet of the mammalian plasma membrane. In addition to this shared mode of membrane binding PvPLP2 displays a secondary synergistic interaction side-on from its principal bilayer interface. This study underlines the substantial differences between the biophysical properties of the APCβ domains of Apicomplexan PLPs, which reflect their significant sequence diversity. Such differences will be important factors in determining the cell targeting and membrane-binding activity of the different proteins, in their different developmental roles within parasite life cycles.

scholarly journals The helminth infracommunities of the wood mouse (Apodemus sylvaticus) two years after the fire in Mediterranean forests

2013 ◽  
Vol 50 (1) ◽  
pp. 27-38 ◽  
Author(s):  
I. Torre ◽  
A. Arrizabalaga ◽  
C. Feliu ◽  
A. Ribas
Keyword(s):  
Species Richness ◽  
Life Cycle ◽  
Wood Mouse ◽  
Final Host ◽  
Life Cycles ◽  
Helminth Species ◽  
Mediterranean Forests ◽  
Intermediate Hosts ◽  
Wood Mice ◽  
Short Period

AbstractParasites have been recognized as indicators for natural or man-induced environmental stress and perturbation. In this article, we investigated the role of two non-exclusive hypotheses on the response of helminths of wood mice to fire perturbation: 1) a reduction of the helminth infracommunity (species richness) in post-fire areas due to the temporal lack of worms with indirect (complex) life cycles linked to intermediate hosts that are more specialized than the final host, and 2) an increase of the abundance of helminths with direct (simple) life cycles as a response of increasing abundances of the final host, may be in stressful conditions linked to the post-fire recolonization process.We studied the helminth infracommunities of 97 wood mice in two recently burned plots (two years after the fire) and two control plots in Mediterranean forests of NE Spain. Species richness of helminths found in control plots (n = 14) was twice large than in burned ones (n = 7). Six helminth species were negatively affected by fire perturbation and were mainly or only found in unburned plots. Fire increased the homogeneity of helminth infracommunities, and burned plots were characterised by higher dominance, and higher parasitation intensity. We found a gradient of frequency of occurrence of helminth species according to life cycle complexity in burned areas, being more frequent monoxenous (66.6 %), than diheteroxenous (33.3 %) and triheteroxenous (0 %), confirming the utility of helminths as bioindicators for ecosystem perturbations. Despite the short period studied, our results pointed out an increase in the abundance and prevalence of some direct life cycle helminths in early postfire stages, whereas indirect life cycle helminths were almost absent. A mismatch between the final host (that showed a fast recovery shortly after the fire), and the intermediate hosts (that showed slow recoveries shortly after the fire), was responsible for the loss of half of the helminth species.

scholarly journals Introduction

Robotica ◽  
2001 ◽  
Vol 19 (5) ◽  
pp. 465-466
Author(s):  
Gamini Dissanayake
Keyword(s):  
Large Scale ◽  
Autonomous Systems ◽  
Cargo Handling ◽  
Field Robotics ◽  
Research Areas ◽  
Hazardous Environments ◽  
Fusion Safety ◽  
Aerospace Systems ◽  
Safety And Reliability ◽  
And Control

Field robotics is the use of autonomous robotic systems in highly challenging applications areas including; mining, construction, cargo handling, agriculture, subsea and aerospace systems. The focus of field robotics research is on large-scale outdoor autonomous systems in applications that are characterised by relatively unstructured, difficult and often hazardous environments. It draws together the most advanced research areas in robotics, including; navigation and control, sensing and data fusion, safety and reliability, and planning and logistics.

Experimental life-cycle studies of Raillietiella gehyrae Bovien, 1927 and Raillietiella frenatus Ali, Riley and Self, 1981: pentastomid parasites of geckos utilizing insects as intermediate hosts

Parasitology ◽  
1983 ◽  
Vol 86 (1) ◽  
pp. 147-160 ◽  
Author(s):  
J. H. Ali ◽  
J. Riley
Keyword(s):  
Life Cycle ◽  
Early Development ◽  
Post Infection ◽  
Egg Production ◽  
Fat Body ◽  
Life Cycles ◽  
Stage Larva ◽  
Intermediate Hosts ◽  
Selective Filter ◽  
Complete Development

SUMMARYThe life-cycles of two closely related cephalobaenid pentastomids, Raillietiella gehyrae and Raillietiella frenatus, which utilize geckos as definitive hosts and cockroaches as intermediate hosts, have been investigated in detail. Early development in the fat-body of cockroaches involves 2 moults to an infective, 3rd-stage larva which appears from 42–44 days post-infection. Complete development in geckos involves a further 5 moults in the case of males and 6 for females. Males mature precociously and copulation is a once-in-a-lifetime event which occurs around day 80 post-infection when both sexes are the same size but the uterus of the female is undeveloped. Sperm, stored in the spermathecae, is used to fertilize oocytes which slowly accumulate in the developing saccate uterus. Patency commences when the uterus carries approximately 4000–5500 eggs but only 25–36 % of these contain fully developed primary larvae. Since only mature eggs are deposited, we postulate that the vagina (?) of the female must be equipped with a selective filter that allows through large eggs but retains smaller, immature eggs. Thus the only limit on fecundity is the total number of sperms in the spermathecae and this is precisely the same factor that constrains egg production in the advanced order Porocephalida.

scholarly journals Circulation Pathways of Trematodes of Freshwater Gastropod Mollusks in Forest Biocenoses of the Ukrainian Polissia

2019 ◽  
Vol 53 (1) ◽  
pp. 13-22 ◽  
Author(s):  
E. P. Zhytova ◽  
L. D. Romanchuk ◽  
S. V. Guralska ◽  
O. Yu. Andreieva ◽  
M. V. Shvets
Keyword(s):  
Life Cycle ◽  
Life Cycles ◽  
Trematode Species ◽  
Intermediate Hosts ◽  
Alaria Alata ◽  
Gastropod Mollusks ◽  
Second Intermediate Host ◽  
Host Life ◽  
Taxonomic Groups ◽  
Diversity Of Life

Abstract This is the first review of life cycles of trematodes with parthenitae and larvae in freshwater gastropods from forest biocoenoses of Ukrainian Polissia. Altogether 26 trematode species from 14 families were found circulating in 13 ways in molluscs from reservoirs connected with forest ecosystems of the region. Three-host life cycle is typical of 18 trematode species, two-host life cycle has found in 7 species, and four-host cycles has found in one species. Alaria alata Goeze, 1782, has three-host (Shults, 1972) and four-host cycles. Opisthioglyphe ranae (Froehlich, 1791) can change three-host life cycle to two-host cycle replacing the second intermediate host (Niewiadomska et al., 2006) with the definitive host. Species with primary two-host life cycle belong to Notocotylidae Lühe, 1909, Paramphistomidae Fischoeder, 1901 and Fasciolidae Railliet, 1758 families. Trematodes with three-host cycle have variable second intermediate hosts, including invertebrates and aquatic or amphibious vertebrates. Definitive hosts of trematodes are always vertebrates from different taxonomic groups. The greatest diversity of life cycles is typical for trematodes of birds. Trematodes in the forest biocoenoses of Ukrainian Polissia infect birds in six ways, mammals in three, amphibians in four, and reptiles in one way. The following species have epizootic significance: Liorchis scotiae (Willmott, 1950); Parafasciolopsis fasciolaemorpha Ejsmont, 1932; Notocotylus seineti Fuhrmann, 1919; Catatropis verrucosa (Frölich, 1789) Odhner, 1905; Cotylurus cornutus (Rudolphi, 1808); Echinostoma revolutum (Fröhlich, 1802) Dietz, 1909; Echinoparyphium aconiatum Dietz, 1909; Echinoparyphium recurvatum (Linstow, 1873); Hypoderaeum conoideum (Bloch, 1782) Dietz, 1909; Paracoenogonimus ovatus Kasturada, 1914; Alaria alata Goeze, 1782.

scholarly journals Smartphone and Tablet Application (App) Life Cycle Characterization via Apple App Store Rank

2020 ◽  
Vol 4 (1) ◽  
pp. 44-67
Author(s):  
Han Jia ◽  
Chun Guo ◽  
Xiaozhong Liu
Keyword(s):  
Life Cycle ◽  
Least Squares ◽  
Product Life Cycle ◽  
Large Scale ◽  
Ordinary Least Squares ◽  
Heterogeneous Data ◽  
Life Cycles ◽  
Volume Data ◽  
App Store ◽  
Management Domain

AbstractWith the rapid growth of the smartphone and tablet market, mobile application (App) industry that provides a variety of functional devices is also growing at a striking speed. Product life cycle (PLC) theory, which has a long history, has been applied to a great number of industries and products and is widely used in the management domain. In this study, we apply classical PLC theory to mobile Apps on Apple smartphone and tablet devices (Apple App Store). Instead of trying to utilize often-unavailable sales or download volume data, we use open-access App daily download rankings as an indicator to characterize the normalized dynamic market popularity of an App. We also use this ranking information to generate an App life cycle model. By using this model, we compare paid and free Apps from 20 different categories. Our results show that Apps across various categories have different kinds of life cycles and exhibit various unique and unpredictable characteristics. Furthermore, as large-scale heterogeneous data (e.g., user App ratings, App hardware/software requirements, or App version updates) become available and are attached to each target App, an important contribution of this paper is that we perform in-depth studies to explore how such data correlate and affect the App life cycle. Using different regression techniques (i.e., logistic, ordinary least squares, and partial least squares), we built different models to investigate these relationships. The results indicate that some explicit and latent independent variables are more important than others for the characterization of App life cycle. In addition, we find that life cycle analysis for different App categories requires different tailored regression models, confirming that inner-category App life cycles are more predictable and comparable than App life cycles across different categories.

Life History Studies on Trematodes of the Subfamily Reniferinae

Parasitology ◽  
1933 ◽  
Vol 25 (4) ◽  
pp. 518-545 ◽  
Author(s):  
S. Benton Talbot
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Life Histories ◽  
Life Cycles ◽  
Small Fish ◽  
Intermediate Hosts ◽  
Natural Group ◽  
Remarkable Similarity ◽  
Physella Gyrina ◽  
Mother Sporocyst

1. The life histories of Lechriorchis primus Stafford, L. tygarti n.sp. and Caudorchis eurinus n.gen. et sp. have been experimentally completed in three hosts, the first complete life histories to be worked out for species of the subfamily Reniferinae.2. The definitive hosts of the three forms were found to be two species of garter snakes, Thamnophis sauritus and T. sirtalis.3. Three species of snails, Physella gyrina, P. parkeri, and P. ancillaria, have been found to serve as the first intermediate host in the life cycles of Lechriorchis primus and Caudorchis eurinus n.gen. et sp., and two species of snails, Physella gyrina and P. heterostropha, in the life cycle of Lechriorchis tygarti n.sp.4. The tadpoles of two species of frogs, Rana clamitans and R. pipiens, were found to serve as the second intermediate hosts in the life cycles of all three trematodes. The cercariae penetrate larvae of Triturus and small fish, but live only a short time in these animals.5. Every stage in the life history of Lechriorchis primus, including egg, miracidium, mother sporocyst, daughter sporocyst, cercaria, metacercaria, and developmental stages in the definitive host, has been described in detail.6. The mother sporocyst of forms having a stylet cercaria is described for the first time.7. The flame cell pattern of the cercariae of L. primus, L. tygarti n.sp., and Caudorchis eurinus n.gen. et sp. has been determined to be of the “2 × 6 × 3’ type. Also the adult stage of C. eurinus was determined to have the same type.8. It has been pointed out that the life histories of the members of the subfamily are uniform in that their life history stages display a remarkable similarity.9. It has been suggested that this uniform type of life cycle and remarkable similarity of larval stages offer the most logical basis for establishing the subfamily Reniferinae as a natural group.

Phenology, behavior, and host-relations of Dermacentor andersoni Stiles in outdoor "rodentaria," and in nature

1968 ◽  
Vol 46 (4) ◽  
pp. 677-689 ◽  
Author(s):  
P. R. Wilkinson
Keyword(s):  
Life Cycle ◽  
Large Scale ◽  
Soil Surface ◽  
Life Cycles ◽  
Unit Weight ◽  
First Year ◽  
Marmota Flaviventris ◽  
New Information ◽  
Approximate Order ◽  
Soil Temperatures

Artificial tick foci or "rodentaria", infested with ovipositing females or larvae, have furnished new information on D. andersoni biology, and a means of mass production of adults for acaricide and other tests. Both a 1-year and a 2-year life cycle were observed, depending on the date the larvae emerged or were put out. Each year, adult ticks wandered near the soil surface in the fall but did not seek hosts or climb up to questing positions until spring. A tendency for the adult ticks to congregate southwards of the point of dropping of the engorged nymphs was discernible.In a large-scale rodentarium involving 24 runways, with four replicates of each of six species of rodents, by far the largest number of adult ticks was produced by Marmota flaviventris, but on a tick per unit weight of rodent basis, this species was low in the approximate order calculated.Adult ticks were ready to feed in mid-December in one trial, but they were inactive in the rodentarium because soil temperatures under the snow were usually about 0 °C, and activity does not begin until about 5 °C. The cycles observed in the rodentaria and the field indicate that both 1- and 2-year life cycles occur in southern British Columbia at an altitude of about 1000 ft. At higher altitudes and latitudes, a 3-year life cycle with overwintering larvae may occur. About 10% of the ticks marked in their first year of activity in 1964 were active the next spring.Female ticks from both 1-year and 2-year cycles were capable of paralyzing sheep.

Parasite risks from raw meat-based diets for companion animals

2020 ◽  
Vol 25 (11) ◽  
pp. 261-267
Author(s):  
Paul A. M. Overgaauw
Keyword(s):  
Life Cycle ◽  
Animal Species ◽  
Companion Animals ◽  
Life Cycles ◽  
Intermediate Hosts ◽  
Prevalence Data ◽  
Raw Meat ◽  
Parasite Infections ◽  
Prevention Method ◽  
Industrialised Countries

In industrialised countries, dogs and cats are more often fed raw meat-based diets. There are microbial hazards associated with raw meat and these can introduce the risk of insufficient nutrition, as a result of nutritional imbalances and deficiencies. A literature review has been carried out to evaluate the risks of parasite infections in companion animals resulting from raw meat-based diets. Parasites present in raw meat use dogs and cats as part of their life cycle, these include protozoa such as Toxoplasma, Sarcocystis, Cystoisospora, Neospora and Hammondia; the nematodes Toxocara spp. and Trichinella; and the tapeworms Taenia spp., Echinococcus granulosus and E. multilocularis. Because of the lack of prevalence data, a valuable risk analysis is difficult. However, the life cycles demonstrate that eating raw meat-based diets and prey animals, can be a route of infection. Such agents can also be present in slaughtered animals. Infections can induce disease in intermediate hosts, but also in humans and other animal species, as an environment can be contaminated with oocysts or eggs. Several parasites can be transmitted via the alimentary route when raw meat-based diets are fed to companion animals. The best prevention method is to feed your companion animals commercial food or to cook meat and organs before feeding.

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