Observations on the establishment, growth, and development of Hymenolepis hopkinsi Schiller, 1951 (Cestoda) in the mallard

1975 ◽  
Vol 53 (12) ◽  
pp. 1892-1897
Author(s):  
J. Daniel McLaughlin
Keyword(s):  
Intermediate Host ◽  
Post Infection ◽  
Growth And Development ◽  
Hyalella Azteca ◽  
Constant Size ◽  
The Mean

Most young H. hopkinsi become established in the caeca of 3-week-old mallards 6 h after ingestion. Migration of H. hopkinsi into the caeca is completed within 36 h after infection. Worms increased in size rapidly between 6 h post infection and 7 days post infection, when the worms became gravid. The worms maintained a relatively constant size from day 7 until the termination of the experiment (day 19). Proglottid production begins 12–24 h after infection and the number increases rapidly until day 7. The mean number of proglottids per worm remained relatively constant until the termination of the experiment. Egg packets of H. hopkinsi are passed periodically in the caecal evacuations beginning 7 days after infection. These are infective immediately to the intermediate host Hyalella azteca.

Hyalella azteca (Amphipoda) as an intermediate host of the nematode Streptocara crassicauda

1989 ◽  
Vol 67 (9) ◽  
pp. 2335-2340 ◽  
Author(s):  
Robert J. A. Laberge ◽  
J. Daniel McLaughlin
Keyword(s):  
Life Cycle ◽  
Intermediate Host ◽  
Post Infection ◽  
Anas Platyrhynchos ◽  
Hyalella Azteca ◽  
Domestic Ducks ◽  
Fecal Samples ◽  
Larval Stages ◽  
Second Stage ◽  
Third Stage

The life cycle of Streptocara crassicauda (Creplin, 1829) was studied experimentally in the amphipod Hyalella azteca (Saussure). Of 2946 H. azteca that survived exposure, 699 were infected. Developing larval stages were found almost exclusively in the cephalic haemocoel. At 18–20 °C, moulting first-stage larvae were observed initially on day 11 and moulting second-stage larvae on day 15 post infection. The moult was not synchronous and moulting stages were found for several days after the initial observation. Third-stage larvae were found as early as day 19 post infection. The larval stages found in H. azteca are described. Mature females containing larvated eggs were recovered from domestic ducks (Anas platyrhynchos dom.) 9–21 days post exposure, and eggs were found in fecal samples on day 26. None of the females recovered from ducks 42 days post infection contained larvated eggs.

Growth and development of collagen fibrils in immature tissues from rat and sheep

1981 ◽  
Vol 212 (1186) ◽  
pp. 85-92 ◽  
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Collagen Fibril ◽  
Growth And Development ◽  
Collagen Fibrils ◽  
Diameter Distribution ◽  
Rat Tissues ◽  
Transmission Electron ◽  
The Mean ◽  
Fibril Diameter

The collagen fibril diameter distribution of four immature tissues from both rat and sheep have been determined from transverse sections observed in the transmission electron microscope. In many instances before birth, the form of the distribution for the tissues is both unimodal and sharp and the mean diameters of the distributions lie close to a multiple of 80 Å. For some tissues, the collagen fibril diameter distributions may be resolved into a number of components, each of which represents a population of fibrils with a diameter close to a multiple of 80 Å (8 nm). These data confirm and extend previous observations by the authors that small collagen fibrils all have diameters that are multiples of about 80 Å and that the fibril growth occurs by the accretion of 80 Å units. The form of the collagen fibril diameter distribution at birth is broad for the sheep tissues but narrow for the rat tissues, thus confirming that the range of fibril diameters at this stage of life reflects the differing degree of development of precocious and altricious animals.

THE ROLE OF EDUCATED LEADERS IN ECONOMIC GROWTH AND DEVELOPMENT: EVIDENCE FROM CENTRAL AFRICAN REPUBLIC AND SINGAPORE

2018 ◽  
Vol 65 (01) ◽  
pp. 81-102
Author(s):  
OLUWOLE OWOYE ◽  
OLUGBENGA A. ONAFOWORA
Keyword(s):  
Economic Growth ◽  
Growth And Development ◽  
Central African Republic ◽  
Economic Growth And Development ◽  
Highly Educated ◽  
Educational Attainments ◽  
Fundamental Causes ◽  
The Mean ◽  
Neoclassical Growth

This paper postulates that highly educated leaders matter in economic growth and development and that this is one of the fundamental causes of the differences in income between countries. To verify this assertion, we examine Central African Republic and Singapore within the neoclassical growth model that incorporates educational attainments of leaders as the functionally relevant explanatory variable. We found the mean years of schooling of educated leaders to be statistically and significantly different in both countries, but more importantly, educational attainments of leaders have a positive and statistically significant effect on economic growth in Singapore, but negative in Central African Republic.

The influence of second intermediate host species on the infectivity of metacercarial cysts of Echinoparyphium recurvatum

1999 ◽  
Vol 73 (2) ◽  
pp. 143-145 ◽  
Author(s):  
A.M. McCarthy
Keyword(s):  
Intermediate Host ◽  
Definitive Host ◽  
Host Species ◽  
Post Infection ◽  
Rana Temporaria ◽  
Biomphalaria Glabrata ◽  
Reproductive Status ◽  
Intermediate Hosts ◽  
Potential Influence ◽  
Second Intermediate Host

The potential influence of second intermediate host species on the infectivity of metacercarial cysts of Echinoparyphium recurvatum to the definitive host Anas platyrhynchos was examined experimentally. Echinoparyphium recurvatum metacercarial cysts were obtained from the following experimentally infected second intermediate hosts 14 days post expsoure to cercariae: Lymnaea peregra; Physa fontinalis; L. stagnalis;Planorbis planorbis; Biomphalaria glabrata; tadpoles of the amphibian Rana temporaria. Metacercarial cysts from each of these hosts were fed, in doses of 50 cysts per individual, to separate groups composed of between four and eight, 3-day-old A. platyrhynchos ducklings. All A. platyrhynchos were necropsied 15 days post-infection and the number, size, and reproductive status of E. recurvatum worms in the intestine was recorded. Analyses of variance on the number (transformed log (x + 1)) and size of worms revealed no significant differences in worms originating from metacercariae formed in the different second intermediate hosts (worm number P > 0.05, and worm size P > 0.05). All worms recovered were found to be gravid. It is therefore concluded that the species of second intermediate host utilized does not influence the infectivity of the metacercarial cyst of E. recurvatum, nor the subsequent establishment and reproductive status of the parasite in A. platyrhynchos.

scholarly journals Effect of generator (exhaust) fumes on the growth and development of Lycopersicum esculentus (tomato)

2016 ◽  
Vol 20 (2) ◽  
pp. 335-340
Author(s):  
M.N. Chukwu ◽  
E.A. Adams
Keyword(s):  
Growth Rate ◽  
Correlation Coefficient ◽  
Analysis Of Variance ◽  
Air Pollutants ◽  
Growth And Development ◽  
Exhaust Fumes ◽  
The Mean ◽  
The Government ◽  
Level Of Significance ◽  
Source Of Pollution

The effects of generator (Exhaust) Fumes on the growth and development of Lycopersicum esculentus were evaluated in this study. It involved sowing ten seeds of L. esculentus in plastic pots. These were allowed to germinate and stabilize for two weeks after which they were exposed to 0.75KVA generator fumes 8 hours a day at the distance of 3 m, 6 m, and 9 m respectively from the source while the control was retained at the planting site. Results were analyzed using analysis of variance (ANOVA) and Pearson’s correlation coefficient at 5% level of significance. Although the mean dry weights of the plants increased as the distance of the plants from the source of pollution increased, only the 3 m treatment led to significant reduction of the growth rate of the seedlings (p < 0.05). The heights of  the plants were adversely affected by the fume emission especially at the distance of 3 m away from the source (p < 0.05). The leaf number per plant increased as the distance of the plants from the source of pollution increased with significant effects on plant from distance of 3 m and 6 m at the later stage of their growth (p < 0.05). Significant differences (p < 0.05) were observed among the plants in the different treatments for the different parameters measured.. Farmers should locate their farmlands at a distance of at least 50 km away from the factories to minimize effect of air pollutants and the government should also place a ban on importation of old generators.Keywords: generator fume, emission, Lycopersicum esculentus, growth, germination

Development ofFasciola hepaticainLymnaea columellainfected with miracidia derived from cattle and marmoset infections

2008 ◽  
Vol 82 (1) ◽  
pp. 81-84 ◽  
Author(s):  
E.A. Mendes ◽  
W.S. Lima ◽  
A.L. de Melo
Keyword(s):  
Survival Rate ◽  
Intermediate Host ◽  
Post Infection ◽  
Fasciola Hepatica ◽  
Bos Taurus ◽  
Snail Host ◽  
Vertebrate Host ◽  
Infection Rates ◽  
Host Origin ◽  
Cattle Faeces

AbstractThe development ofFasciola hepaticafrom two species of definitive hosts, i.e. cattle (Bos taurus) and a marmoset (Callithrix penicillata) in the snailLymnaea columellawas determined based on the production of rediae and cercariae and snail survival rate. More rediae and cercariae at 60–74 days post-infection were produced by snails infected by cattle-derived miracidia (cattle group) than by those infected by marmoset-derived miracidia (marmoset group). Among theL. columellaparasitized by the marmoset group, the survival rate and the percentage of positive snails were higher than among those parasitized by the cattle group. Eggs ofF. hepaticareleased in cattle faeces were significantly bigger than those released in marmoset faeces. Miracidia originating from parasites that completed their development in cattle were more efficient in infecting the intermediate host. These results suggest that vertebrate-host origin influences the eggs produced by the parasite and the infection rates in the snail hostL. columella.

Influence of Sediment on Anthracene Uptake, Depuration, and Biotransformation by the Amphipod Hyalella azteca

1983 ◽  
Vol 40 (3) ◽  
pp. 298-305 ◽  
Author(s):  
Peter F. Landrum ◽  
Donald Scavia
Keyword(s):  
Rate Constant ◽  
Body Burden ◽  
Water Concentration ◽  
Hyalella Azteca ◽  
Benthic Organisms ◽  
Organic Sediment ◽  
Wet Weight ◽  
The Mean ◽  
Organic Sediments ◽  
State Body

Uptake, depuration, and biotransformation rates of anthracene were determined for Hyalella azteca (Amphipoda, Crustacea) in both the presence and the absence of sediment. The mean rate constant ± SE for uptake from water was the same for cases with or without sediment, 255 ± 76 mL∙(g animal wet weight)−1∙h−1. The rate constant for uptake of sediment-associated anthracene was 19 ± 5 g dry sediment∙(g animal wet weight)−1∙h−1 for an organic sediment. Depuration increased by a factor of three in the presence of sediment. Sediment-associated anthracene, compound sorbed to sediment and in pore water, was estimated to contribute 77% of the steady-state body burden. These animals, and presumably other benthic organisms exposed to toxicants in organic sediments, are at higher risk than animals not associated with sediments. Further, bioconcentration factors based on the ratio of body burden to water concentration are overestimates for H. azteca and other benthic organisms that obtain a large proportion of their body burden from sediment.Key words: anthracene, Hyalella azteca, sediment, PAH

scholarly journals Volume and surface changes in vero cell and its nucleus after infection with measles virus: a stereological study

2011 ◽  
Vol 2 (1) ◽  
pp. 18
Author(s):  
Ali Noorafshan ◽  
Mohammad Motamedifar ◽  
Saied Karbalay-Doust
Keyword(s):  
Vero Cell ◽  
Post Infection ◽  
Measles Virus ◽  
Plaque Assay ◽  
Vero Cells ◽  
Uninfected Control ◽  
Mean Cell Volume ◽  
Significant Difference ◽  
Infected Cells ◽  
The Mean

Measles virus has no or indistinctive cytopathic effects (CPE) in cell couture system. Employment of some detecting methods like plaque assay or stereologic experiments, as a method of detecting of viral infection in the cells would be applicable. The aim of this study was investigating the early changes in quantitative parameters of measles virus infected Vero cells. Stereological methods using invariator, were applied for the first time to estimate cell and nucleus volume and cell surface of the infected Vero cell line with the measles virus.This method can be applied on other cultured cells.Vero cells grown in tissue culture plates for 48 hours at 36˚C were infected with 100TCID50 of AiK strain of measles virus. Volume and surface of the infected Vero cells were studied at 4, 9 and 25 hours post infection along with uninfected control cells. The mean cell volume and surface of the cells infected with measles virus, increased ~87% and ~50%, respectively, 4 hours post-infection, as compared with the uninfected control. The nuclei did not show any differences. The mean parameters of infected cells in other time intervals showed no significant difference comparing with the control cells. Although there are other specific methods, stereology may be used as an integrated protocol to detect cytophatic changes of the measles virus infected cells early in the permissive cell culture system.

scholarly journals Follow-up of premature children with high risk for growth and development delay: a multiprofessional assessment

2010 ◽  
Vol 8 (2) ◽  
pp. 180-186 ◽  
Author(s):  
Marcia de Freitas ◽  
Ana Merzel Kernkraut ◽  
Simone Maria Amadio Guerrero ◽  
Sonia Teresa Gaidzakian Akopian ◽  
Sandra Harumi Murakami ◽  
...  
Keyword(s):  
Birth Weight ◽  
Growth And Development ◽  
Physical Therapist ◽  
Tertiary Care ◽  
Population Group ◽  
Care Hospital ◽  
Major Development ◽  
Development Delay ◽  
Speech Therapist ◽  
The Mean

ABSTRACT Objective: To describe the activities of a multiprofessional outpatient clinic performed by neonatologist, physiatrist, physical therapist, occupational therapist, speech therapist, audiologist and psychologist, who evaluated the development of premature newborns. Methods: Twenty children born at a tertiary-care hospital (São Paulo, Brazil), between April 2006 and April 2007, with birth weight below 1250 g or less than 32 weeks of gestation, were evaluated. The multiprofessional evaluation included assessment of development using the Bayley III scale, at the corrected age of 3, 6, 9, 12, 18 and 24 months. Results: The mean gestation age at birth was 28.8 weeks; mean birth weight was 1055 g. The mean maternal age was 35 years and the mean length of stay of neonates was 46.3 days. Fifteen percent of children presented impaired sensory motor skills, 20% had hearing abnormalities and 10% motor alterations. Bayley III showed alterations in the communication area in 10% of subjects and in the motor area in 10% of individuals. The parents were oriented to stimulate the child or a specific intervention was suggested. The major development delay was observed between 6 and 18 months of age and the development was improved at 24 months of age. Conclusions: Most children evaluated had improved growth and development at 24 corrected-age months. Further studies with a larger sample are recommended, as well as the possibility to follow this population group up till the primary school.

Hymenolepis diminuta: influence of metacestodes on synthesis and secretion of fat body protein and its ovarian sequestration in the intermediate host, Tenebrio molitor

Parasitology ◽  
1986 ◽  
Vol 93 (1) ◽  
pp. 111-120 ◽  
Author(s):  
Hilary Hurd ◽  
C. Arme
Keyword(s):  
Intermediate Host ◽  
Post Infection ◽  
Fat Body ◽  
Tenebrio Molitor ◽  
Hymenolepis Diminuta ◽  
Body Protein ◽  
Concomitant Reduction ◽  
Fat Bodies

SUMMARYFemale Tenebrio molitor infected with metacestodes of Hymenolepis diminuta exhibit elevated concentrations of female-specific proteins in their haemolymph and the origin of these has been investigated. Following a 4 h in vitro incubation with [14C]leucine, fat bodies from non-infected females secreted 13 times more protein than those from females 12 days post-infection. A comparison of the uptake in vivo of radio-isotope labelled amino acids by ovaries from non-infected and infected beetles of various ages revealed no differences; however, a 51·5% decrease in protein sequestration was detected in females 12 days post-infection. Electrophoresis of homogenates of radio-isotope labelled ovaries demonstrated that the majority of label was associated with vitellin sub-units. It is suggested that the decrease in vitellogenin sequestration associated with infection results in an increase in the haemolymph concentration of these proteins despite a concomitant reduction in their secretion by fat bodies. Both fat body synthesis and ovarian sequestration are under juvenile hormone control and it is proposed that metacestodes of H. diminuta may cause a reduction in the concentration of this hormone in the intermediate host.

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