Studies on resistance in calves to experimental infection with the nodular worm, Oesophagostomum radiatum (Rudolphi 1803). II. The role of the respective stages of the parasitic life cycle in the stimulation of resistance

1963 ◽  
Vol 14 (5) ◽  
pp. 704 ◽  
Author(s):  
FHS Roberts ◽  
RF Riek ◽  
RK Keith
Keyword(s):  
Life Cycle ◽  
Fourth Stage ◽  
Development Stages ◽  
The Third ◽  
Surgical Implants ◽  
Series Of Experiments ◽  
Parasitic Life Cycle ◽  
Fourth Stage Larva ◽  
Stimulation Of

Investigations are reported which attempted to define the role of the respective stages of the parasitic life cycle ofOesophagostomum radiatum in the stimulation of resistance in calves to reinfection with this parasite. In one series of experiments with calves reared worm-free, infection was restricted to known stages by treatment with an anthelmintic, and in another series by surgical implants of worms. Subsequent reinfection showed that the early development stages of the parasite up to the early fourth stage larva in the gut lumen, and the exsheathing fluid released at the third and fourth ecdyses, were not essential for the stimulation of resistance. The results also suggest that ability to stimulate resistance increases as the worms mature.

The parasitic life-cycle of Haemonchus Placei (Place) Ransom (Nematoda: Trichostrongylidae)

1956 ◽  
Vol 4 (2) ◽  
pp. 146 ◽  
Author(s):  
KC Bremner
Keyword(s):  
Life Cycle ◽  
Small Proportion ◽  
Fourth Stage ◽  
Patent Period ◽  
Gastric Glands ◽  
The Third ◽  
Final Moult ◽  
Parasitic Life Cycle ◽  
Haemonchus Placei

The parasitic life-cycle of Haemonchus placei (Place 1893) Ransom 1911 is described and compared with that of H. contortus (Rudolphi 1803) Cobb 1898. The third ecdysis of H. placei larvae occurred 36-76 hr after infestation, and the fourth and final moult occurred 11-14 days after infestation in the majority of larvae. Many third- and fourth-stage larvae penetrated deeply into the gastric glands of the mucosa. A small proportion of larvae did not develop beyond the early fourth stage, even after the majority had become adult. The pre-patent period of H. placei was estimated to be about 11 days longer than that of H. contortus.

Studies on the life-history of Bunostomum phlebotomum (Railliet, 1900), a hookworm parasite of cattle

Parasitology ◽  
1946 ◽  
Vol 37 (3-4) ◽  
pp. 192-201 ◽  
Author(s):  
J. F. A. Sprent
Keyword(s):  
Infective Larva ◽  
Stage Larva ◽  
Fourth Stage ◽  
Larval Stages ◽  
The Third ◽  
Third Stage ◽  
History Of ◽  
Time Required ◽  
Cutaneous Blood ◽  
Fourth Stage Larva

A description is given of the processes of copulation, formation of the egg and spermatozoon, cleavage, embryogeny and hatching in B. phlebotomum. These processes were found to be essentially similar to those in other strongyle nematodes.The anatomy of the first three larval stages is described and the observations of Conradi & Barnette (1908) and Schwartz (1924) were largely confirmed.Penetration of the skin of calves by the infective larva was observed histologically. The larvae were found to have reached the dermis within 30 min. and to have penetrated the cutaneous blood vessels within 60 min. of application to the skin. The larvae were found in the lung where the third ecdysis was in progress 10 days after penetration of the skin. A description is given of the growth of the third-stage larva in the lung, the changes which take place during the third ecdysis, and the anatomy of the fourth-stage larva.The fourth-stage larvae exsheath in the lungs and travel to the intestine. After a period of growth in which sexual differentiation takes place, the fourth ecdysis occurs and the adult parasite emerges. The time required for the attainment of maturity was found to be somewhere between 30 and 56 days after penetration of the skin.This paper was written at the Ministry of Agriculture and Fisheries Veterinary Laboratories, Wey-bridge, and the writer would like to express his gratitude to the Director, Prof. T. Dalling, also to Dr W. R. Wooldridge, chairman of the Council of the Veterinary Educational Trust for their help and encouragement. The writer's thanks are also due to Dr H. A. Baylis, Prof. R. T. Leiper and Dr E. L. Taylor for their advice and help on technical points, and to Mr R. A. O. Shonekan, African laboratory assistant, for his able co-operation.

Effects of methotrexate on the parasitic development of the nematode Dictyocaulus viviparus (Metastrongylidae), and on the immune response of infected guinea-pigs

Parasitology ◽  
1971 ◽  
Vol 63 (1) ◽  
pp. 145-156 ◽  
Author(s):  
R. J. M. Wilson
Keyword(s):  
Immune Response ◽  
Developmental Stages ◽  
Stage Larva ◽  
Immune Mechanism ◽  
Fourth Stage ◽  
Dictyocaulus Viviparus ◽  
The Third ◽  
Effective Immune Response ◽  
Early Developmental ◽  
Fourth Stage Larva

Methotrexate inhibited the growth of D. viviparus by acting either on the moult from the third- to the fourth-stage larva or on the growth of fourth-stage larva itself. Despite these effects of the drug, the early developmental stages of the worms primed the immune mechanism of the host; the inductive phase of antibody production was completed in less than 5 days. An effective immune response, however, was blocked by the continued presence of methotrexate which resulted in delayed elimination of a superinfection and the absence of anaphylactic antibody in the serum. Immune elimination appeared to require a quantitative threshold of worm antigen and host antibody.This work was made possible by the generous supply of infective helminth material from Messrs Allen and Hanbury Ltd, Ware, Herts. I should also like to thank Dr J. H. Humphrey and Dr S. R. Smithers of N.I.M.R. for their helpful discussions.

A Possible Role of the Carotid Body in the Pathogenesis of Cluster Headache

Cephalalgia ◽  
1983 ◽  
Vol 3 (4) ◽  
pp. 241-247 ◽  
Author(s):  
Lee Kudrow
Keyword(s):  
Cluster Headache ◽  
Carotid Body ◽  
Cranial Nerves ◽  
Major Influence ◽  
Peripheral Chemoreceptor ◽  
Afferent Pathways ◽  
The Third ◽  
Cyclic Cluster ◽  
Stimulation Of

An hypothesis regarding the possible role of the carotid body in the pathogenesis of cluster headache is presented. It states: 1. The pathways concerned with cyclic cluster periods may begin centrally involving specific areas in the hypothalamus. The major influence of this physiological change is proposed to be an inhibition of the sympathetic and disinhibition of parasympathetic supplies to the carotid body. The result, whether due to increased vasomotor tonus or interruption of intrinsic sympathetic stimulation, is suggested to cause diminished peripheral chemoreceptor activity. 2. The pathway concerned with onset of spontaneous or induced attacks begins, as proposed, with oxygen desaturation-which, upon reaching threshold levels may induce a hyperactive chemoreceptor response, and stimulate through afferent pathways the nuclei of the 7th and 10th cranial nerves and respiratory centers, via the nucleus solitarius. 3. The consequence of this excitation may involve the third suggested pathway resulting in stimulation of peripheral secretory and other receptors innervated by the cranial nerves.

scholarly journals Mutagenesis at Two Distinct Phosphate-Binding Sites Unravels Their Differential Roles in Regulation of Rubisco Activation and Catalysis

2005 ◽  
Vol 187 (12) ◽  
pp. 4222-4228 ◽  
Author(s):  
Yehouda Marcus ◽  
Hagit Altman-Gueta ◽  
Aliza Finkler ◽  
Michael Gurevitz
Keyword(s):  
Binding Sites ◽  
Phosphate Binding ◽  
Bisphosphate Carboxylase ◽  
Photoautotrophic Growth ◽  
The Third ◽  
Rate Of Photosynthesis ◽  
Rubisco Activation ◽  
Positively Charged ◽  
Stimulation Of

ABSTRACT Orthophosphate (Pi) has two antagonistic effects on ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), stimulation of activation and inhibition of catalysis by competition with the substrate RuBP. The enzyme binds Pi at three distinct sites, two within the catalytic site (where 1P and 5P of ribulose 1,5-bisphosphate [RuBP] bind), and the third at the latch site (a positively charged pocket involved in active-site closure during catalysis). We examined the role of the latch and 5P sites in regulation of Rubisco activation and catalysis by introducing specific mutations in the enzyme of the cyanobacterium Synechocystis sp. strain PCC 6803. Whereas mutations at both sites abolished the Pi-stimulated Rubisco activation, substitution of residues at the 5P site, but not at the latch site, affected the Pi inhibition of Rubisco catalysis. Although some of these mutations substantially reduced the catalytic turnover of Rubisco and increased the Km (RuBP), they had little to moderate effect on the rate of photosynthesis and no effect on photoautotrophic growth. These findings suggest that in cyanobacteria, Rubisco does not limit photosynthesis to the extent previously estimated. These results indicate that both the latch and 5P sites participate in regulation of Rubisco activation, whereas Pi binding only at the 5P site inhibits catalysis in a competitive manner.

Role of vasopressin in stimulation of ACTH secretion by angiotensin II in conscious dogs

1986 ◽  
Vol 251 (1) ◽  
pp. E52-E57
Author(s):  
C. K. Klingbeil ◽  
L. C. Keil ◽  
D. Chang ◽  
I. A. Reid
Keyword(s):  
Angiotensin Ii ◽  
Arginine Vasopressin ◽  
Water Deprivation ◽  
Conscious Dogs ◽  
Ang Ii ◽  
Acth Secretion ◽  
Series Of Experiments ◽  
Stimulation Of ◽  
Acth Release

Three series of experiments were performed in conscious dogs to test the possibility that the stimulation of adrenocorticotropin (ACTH) release by angiotensin II (ANG II) is mediated by arginine vasopressin (AVP). In the first protocol, the effect of ANG II on ACTH release was studied in dogs in which endogenous AVP levels had been increased by water deprivation. Water deprivation for 24 h increased plasma AVP concentration from 3.0 +/- 0.5 to 7.7 +/- 0.5 pg/ml (P less than 0.01) and increased the AVP response to the highest dose of ANG II (20 ng X kg-1 X min-1). Despite these changes, water deprivation failed to increase the ACTH response to ANG II. Next, the contribution of endogenous AVP to the stimulation of ACTH release by ANG II was examined using the V1-receptor antagonist, d(CH2)5Tyr[Met]-AVP (10 micrograms/kg iv). The ACTH response to ANG II in the presence of the AVP antagonist (66.4 +/- 3.1 to 100.1 +/- 15.9 pg/ml) was not significantly less than that in its absence (53.0 +/- 4.8 to 72.2 +/- 11.1 pg/ml). Finally, ANG II and AVP were infused in combination to determine whether there is a synergism between these two peptides in the release of ACTH. In one protocol, AVP and ANG II were infused separately and in combination. The ACTH response to ANG II and AVP in combination (48.7 +/- 6.5 to 61.5 +/- 8.5 pg/ml) was not enhanced compared with the responses to ANG II (59.8 +/- 7.3 to 71.0 +/- 10.1 pg/ml) or AVP (48.8 +/- 5.7 to 55.6 +/- 6.5 pg/ml) alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Life cycle and seasonal dynamics of Cucullanus cirratus O.F. Müller, 1777 (Nematoda, Ascaridida, Seuratoidea, Cucullanidae) in Atlantic cod, Gadus morhua L.

2000 ◽  
Vol 78 (2) ◽  
pp. 182-190 ◽  
Author(s):  
Marianne Køie
Keyword(s):  
Life Cycle ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Experimental Studies ◽  
Fourth Stage ◽  
Mature Adult ◽  
Pyloric Caeca ◽  
The Third ◽  
Total Length ◽  
Third Stage

Mature specimens of Cucullanus cirratus O.F. Müller, 1777 (Cucullanidae) were obtained from the pyloric caeca and intestine of Atlantic cod, Gadus morhua L., from Danish waters. Eggs embryonate in seawater. Third-stage larvae about 400 µm long, with amphids and dereids, hatch from the egg. Experimental studies indicated that third-stage larvae were infective to calanoid and cyclopoid copepods and sand gobies, Pomatoschistus minutus (Pisces, Gobiidae). Larvae entered the haemocoel of copepods but did not grow. In gobies, the third-stage larvae entered the intestinal mucosa and grew to 800 µm in length within 6 months. They were not encapsulated. Experimental infections of cod (8-30 cm long) showed that free-living third-stage larvae are not infective, whereas >700 µm long third-stage larvae from gobies survived in the cod. Third-stage larvae 700-1200 µm long occur in the stomach mucosa, where they develop and moult to fourth-stage larvae. The fourth-stage larvae then migrate to the pyloric caeca and anterior part of the intestine, where they moult and develop to the mature adult stage. No developmental stage became encapsulated. Naturally infected cod (>20 cm total length) harboured moulting third-stage larvae and <2 mm long fourth-stage larvae 2 months post capture. Naturally infected 4- to 5-month-old codlings (8-10 cm total length) harboured 2-3 mm long fourth-stage larvae only, indicating that they acquired the third-stage larvae as planktivorous fry only a few centimetres long. Cucullanus cirratus may have a life-cycle that involves copepod transport hosts and fish (gobies or cod fry) intermediate hosts. Postcyclic development occurs in gadoids when an infected cod is consumed by another cod (cannibalism). Examinations of 350 (8-78 cm total length) naturally infected cod showed that group 1 and older cod are infected throughout the year, with maximum prevalence of third-stage larvae in spring and summer. The greatest prevalence of gravid worms was observed in autumn.

scholarly journals PERAN MEDIA SOSIAL “FACEBOOK” DALAM PROSES PEMBENTUKAN OPINI PUBLIK MENJELANG PEMILIHAN UMUM LEGISLATIF 2019 DI KABUPATEN ACEH JAYA

2019 ◽  
Vol 4 (2) ◽  
Author(s):  
Aminah Aminah
Keyword(s):  
Social Media ◽  
Public Opinion ◽  
Field Research ◽  
Fourth Stage ◽  
The Third ◽  
Reading Material ◽  
Library Research ◽  
Espoused Values ◽  
Third Stage

This research aims to explain about to examine about the role of social media in making public decisions ahead of the legislative election 2019 in the district of Aceh Jaya. The data that is required in writing is obtained through library research and field. Library research done with how to read text books, legislation, and other reading material related to this research. While field research done by interviewing informants. The results of the study showed that the process of forming public opinion cannot be formed by itself. The process of forming public opinion consists of several stages, namely Phase I which is caused by several factors: cultural background, past, espoused values and news that develops. Stage 2 the formation of perception in the community, the third stage is formed, the fourth stage is the consensus, namely the last and last process or agreement on a public opinion. Through Facebook media, the process of forming public opinion is very fast. This happens to the maximum extent possible for people who use social media

scholarly journals First record of Bulimulus tenuissimus (Mollusca) as potential experimental intermediate host of Angiostrongylus cantonensis (Nematoda)

2019 ◽  
Vol 79 (4) ◽  
pp. 686-696 ◽  
Author(s):  
F. G. Martins ◽  
J. S. Garcia ◽  
E. J. L. Torres ◽  
M. A. J. Santos ◽  
C. L. Massard ◽  
...  
Keyword(s):  
Life Cycle ◽  
Intermediate Host ◽  
Amorphous Material ◽  
Angiostrongylus Cantonensis ◽  
Muscular Tissue ◽  
Wild Rodents ◽  
Intermediate Hosts ◽  
Post Exposure ◽  
The Third

Abstract Snails are essential to complete the life cycle of the metastrongylid nematode Angiostrongylus cantonensis, the causative agent of infections in domestic and wild animals, mainly rodents, and also of neural angiostrongyliasis or eosinophilic meningitis in humans. There are many reports of mollusks that can act as intermediate hosts of this parasite, especially freshwater snails and the African giant Achatina fulica. The terrestrial gastropod Bulimulus tenuissimus is widely distributed in Brazil and other species of the same genus occur in Brazil and other countries, overlapping regions in which there are reports of the occurrence of A. cantonensis and angiostrongyliasis. In spite of this, there are no records in the literature of this species performing the role of intermediate host to A. cantonensis. The present study analyzed the experimental infection with first-stage larvae of A. cantonensis, under laboratory conditions, of B. tenuissimus, by using histology and electron microscopy techniques. Three weeks after exposure to L1 larvae, it was possible to recover L3 larvae in small numbers from the infected snails. Developing larvae were observed in the cephalopedal mass (foot), ovotestis, and mantle tissues, being located inside a granulomatous structure composed of hemocyte infiltration, but there was no calcium or collagen deposition in these structures in significant amounts. In the third week post exposure, it was possible observe a sheath around the developing larvae. The infected snails presented reduction in the fibrous muscular tissue in the foot region, loss of the acinar organization in the digestive gland, with increase of amorphous material inside the acini and loss of epithelial pattern of nuclear organization in the acinar cells. However, the ovotestis seemed unaffected by the infection, since there was a large number of developing oocytes and spermatozoa in different stages of formation. The digestion of infected snails allows us the third-stage recovery rate of 17.25%, at 14 days post exposure to the L1. These L3 recovered from B. tenuissimus were used to infect rats experimentally, and 43 days post infection first-stage (L1) larvae of A. cantonensis were recovered from fresh feces. The results presented constituted the first report of the role of B. tenuissimus as an experimental intermediate host to A. cantonensis and shed some light on a possible problem, since the overlapping distribution of B. tenuissimus and A. cantonensis in Brazil and other countries where different species of Bulimulus occur enables the establishment and maintenance of the life cycle of this parasite in nature, with wild rodents as reservoirs, acting as a source of infection to humans, causing neural angiostrongyliasis.

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