Effects of experimental Schistocephalus solidus infections on growth, morphology and sexual development of female three-spined sticklebacks, Gasterosteus aculeatus

Parasitology ◽  
2003 ◽  
Vol 126 (4) ◽  
pp. 359-367 ◽  
Author(s):  
I. BARBER ◽  
P. A. SVENSSON

The use of naturally infected hosts in studies attempting to identify parasite-induced changes in host biology is problematical because it does not eliminate the possibility that infection may be a consequence, rather than a cause, of host trait variation. In addition, uncontrolled concomitant infections may confound results. In this study we experimentally infected individual laboratory-bred female three-spined sticklebacks Gasterosteus aculeatus L. with the pseudophyllidean cestode Schistocephalus solidus [Müller], and compared the morphology and growth patterns of infected females with sham-exposed controls over a 16-week period. Fish were fed a ration of 8% body weight per day. Non-invasive image analysis techniques allowed the growth of individual plerocercoids to be tracked in vivo throughout the course of infection, and patterns of host and parasite growth were determined. Females that developed infections diverged morphometrically from unexposed control females and exposed-uninfected females at 6 weeks post-infection, with the width of the body at the pectoral fins giving the earliest indication of infection success. When including the plerocercoid, infected females gained weight more quickly than controls, but when plerocercoid weight was removed this trend was reversed. There was no effect of infection on the increase in fish length. Plerocercoids grew at different rates in individual hosts, and exhibited measurable sustained weight increases of up to 10% per day. Final estimates of plerocercoid weight from morphometric analysis prior to autopsy were accurate to within +/−17% of actual plerocercoid weight. At autopsy, infected female sticklebacks had significantly lower perivisceral fat reserves but had developed significantly larger ovaries than controls. The results are discussed in relation to previous studies examining natural infections, and the value of utilizing experimental infections to examine ecological aspects of host–parasite interactions is discussed.

1946 ◽  
Vol 23 (1) ◽  
pp. 47-70 ◽  
Author(s):  
J. D. SMYTH

A technique has been elaborated that enabled the plerocercoid larvae of Schistocephalus solidus to be removed from the body cavity of Gasterosteus aculeatus without bacterial contamination. Larvae were cultured in plugged test-tubes under completely aseptic conditions in a variety of balanced salines, glucose salines and nutrient peptone broth. The most successful results were obtained with peptone broth at room temperatures (16-19° C) in which plerocercoids remained active and showed normal behaviour for periods up to 300 days. In ¾ strength Locke's solution, which was found by experiment to be approximately isotonic with Schistocephalus (δ = -0.44 ± 0.02° C), the mean period of normal behaviour was 114 days. In the remaining saline and saline-glucose media, the mean viability and period of normal behaviour was considerably less. In the plerocercoid, histological examination revealed that the genitalia are in an immature condition. During cultivation at room temperatures, the genitalia remained in this undifferentiated condition and showed no signs of undergoing spermatogenesis, oogenesis or vitellogenesis. Plerocercoids were induced to develop into sexually mature adults by raising the temperature of cultivation in peptone broth to 40° C. (i.e. the body temperature of the final host in the natural life cycle). Oviposition took place after 48-60 hr. at this temperature, and histological examination revealed that spermatogenesis, oogenesis, vitellogenesis and shell formation had taken place in a normal manner. The viability of artificially matured Schistocephalus was 4-6 days in vitro--a period equivalent to the viability of the adult in vivo. The eversion of the cirris was observed in each proglottid after 40 hr. cultivation at 40° C. During the sexual process the cirris everted and invaginated at the rate of about once per second. Cross-fertilization between segments of the same worm or with segments of another worm was not observed. Except for one specimen in ¾ strength Locke's solution which underwent spermatogenesis and partial vitellogenesis, larvae cultured in salines or glucose salines at 40° C. died within 1-3 days without further development. Attempts to hatch out the eggs produced by the cultivation of larvae in peptone broth at 40° C. proved unsuccessful. Histological examination revealed that spermatozoa had not been taken into the vagina. It was concluded that the eggs were not fertilized owing to the failure of normal copulation to take place.


2017 ◽  
Vol 234 (2) ◽  
pp. 101-114 ◽  
Author(s):  
Thanh Q Dang ◽  
Nanyoung Yoon ◽  
Helen Chasiotis ◽  
Emily C Dunford ◽  
Qilong Feng ◽  
...  

Altered permeability of the endothelial barrier in a variety of tissues has implications both in disease pathogenesis and treatment. Glucocorticoids are potent mediators of endothelial permeability, and this forms the basis for their heavily prescribed use as medications to treat ocular disease. However, the effect of glucocorticoids on endothelial barriers elsewhere in the body is less well studied. Here, we investigated glucocorticoid-mediated changes in endothelial flux of Adiponectin (Ad), a hormone with a critical role in diabetes. First, we used monolayers of endothelial cells in vitro and found that the glucocorticoid dexamethasone increased transendothelial electrical resistance and reduced permeability of polyethylene glycol (PEG, molecular weight 4000 Da). Dexamethasone reduced flux of Ad from the apical to basolateral side, measured both by ELISA and Western blotting. We then examined a diabetic rat model induced by treatment with exogenous corticosterone, which was characterized by glucose intolerance and hyperinsulinemia. There was no change in circulating Ad but less Ad protein in skeletal muscle homogenates, despite slightly higher mRNA levels, in diabetic vs control muscles. Dexamethasone-induced changes in Ad flux across endothelial monolayers were associated with alterations in the abundance of select claudin tight junction (TJ) proteins. shRNA-mediated knockdown of one such gene, claudin-7, in HUVEC resulted in decreased TEER and increased adiponectin flux, confirming the functional significance of Dex-induced changes in its expression. In conclusion, our study identifies glucocorticoid-mediated reductions in flux of Ad across endothelial monolayers in vivo and in vitro. This suggests that impaired Ad action in target tissues, as a consequence of reduced transendothelial flux, may contribute to the glucocorticoid-induced diabetic phenotype.


Author(s):  
Zdeněk Mačát ◽  
Adam Bednařík ◽  
Martin Rulík

AbstractParasitic relations between animals are very common in wild nature. In this paper, we studied levels of infection in three-spined stickleback with plerocercoids of Schistocephalus solidus from Puck Bay (Baltic Sea, Poland). The total prevalence of infection was 54.2%, while proportion of infected individuals was significantly higher for females than for males. The body width was found to be significantly positively correlated with the number and the weight of parasites. In spite of the increasing deterioration of the Baltic Sea ecosystem by excessive eutrophication and hypoxia, lower prevalence of infection compared to previous published data indicates that there are likely other factors than pollution affecting the life cycle of parasites and the level of parasitism.


Parasitology ◽  
1965 ◽  
Vol 55 (2) ◽  
pp. 257-268 ◽  
Author(s):  
Morag L. O. McCaig ◽  
C. Adrian Hopkins

Schistocephalus plerocercoids in the weight range 2–200mg F.W. recovered from the perivisceral cavity of Gasterosteus aculeatus were cultured in various media. In a medium composed of 25% horse serum, 0·5% yeast extract, 0·65% glucose and Hanks's saline at pH 7·1, 21°C, 95% air +5% CO2, dry weight increases of up to 500% were recorded in 8 days. The specific growth rate of large plerocercoids was only one-tenth of the rate observed in small plerocercoids. A plerocercoid of double the weight of another had approximately half the specific growth rate.Worms after 8 days cultivation were found to have only slightly higher than normal glycogen and water content, and to be able to mature when heated to 40°C. However, the rate of growth slowed to zero by the 24th day in culture at 21°C. Electron microscopic examination showed a ‘deposit’ formed over the microvilli, thin at 8 days but dense after 21 days.The in vivo glycogen and water content of plerocercoids from 3–300 mg F.W. was determined. Glycogen rose from 24% in plerocercoids of 10mg F. W. to 50–55% in plerocercoids over 80mg F. W. The water content was found to mimic precisely this change, falling from 82% to a plateau of 67–69%.We wish to thank Professor Gareth Owen for permission to use the photograph shown in the Plate and for his help while using the electron microscope. It is also a pleasure to thank Miss Patricia Grant for her technical assistance.


Parasitology ◽  
1967 ◽  
Vol 57 (2) ◽  
pp. 301-314 ◽  
Author(s):  
C. Arme ◽  
R. Wynne Owen

Infections are described of Gasterosteus aculeatus in a pond at Leeds with the plerocercoid larvae of Schistocephalus solidus.Very heavy infections were found in the summer of 1962 and early 1963; many fish harboured over 50 worms and the maximum was 130.For each individual host the relative percentage parasite-weight to host-weight has been determined (parasitization index). In more than 50% of the fish the P.I. exceeded 25; the maximum value was 68·5. The relationship between P.I., numbers of worms and weight of worms is described.Some effects of parasitization on the host are described; they include gross distension of the body, reduction of liver weight, reduction of packed cell volume of erythrocytes and delay in oocyte maturation. In some heavily parasitized individuals spawning is apparently inhibited.Concurrent infections with the microsporidian Glugea anomala are described.Our thanks are due to Mr A. Rennie, B.Sc., of the Yorkshire Ouse and Hull River Authority for drawing our attention to the source of infected sticklebacks, to Mr A. O. Holliday for the preparation of photographs and to Mr G. R. Standley for assistance in the preparation of the slide shown in PI. 1, fig. 3. We also wish to thank Dr J. N. Ball, Department of Zoology, University of Sheffield, for his helpful comments on the gonads of infected fish, and Professor J. M. Dodd, Department of Zoology, University of Leeds, for providing facilities and much helpful discussion. One of us (C. A.) gratefully acknowledges the receipt of a Science Research Council Research Studentship and Fellowship.


Behaviour ◽  
1995 ◽  
Vol 132 (15-16) ◽  
pp. 1223-1240 ◽  
Author(s):  
Iain Barber ◽  
Felicity A. Huntingford

AbstractIn this paper we review recent experimental work on the effects of the parasite Schistocephalus solidus (Cestoda: Pseudophyllidea) on the feeding behaviour of three-spined sticklebacks (Gasterosteus aculeatus L.). We also discuss how increased feeding motivation and subsequent altered foraging behaviour may be a mechanism for parasite-associated changes in the shoaling behaviour of infected sticklebacks. The presence of S. solidus plerocercoids in the body cavity constricts the stomach, increases the handling time for large prey and consequently reduces the profitability of such prey for infected fish. This is reflected in a switch in dietary preference from large to small prey in the laboratory and in altered stomach contents and impaired nutrient reserves in the wild. By altering their hosts' nutritional state by direct competition for nutrients from digested food (and possibly indirectly by altering diet and reducing competitive ability) and also by altering the fishes' appearance, such parasites have the potential to alter the costs and benefits involved in joining a shoal of conspecifics. Experimental work on the shoaling decisions of S. solidus-infected sticklebacks supports this hypothesis, and such behavioural modification is discussed in the context of the manipulation hypothesis of parasite transmission.


2021 ◽  
Author(s):  
Syed Mohammed Musheer Aalam ◽  
Xiaojia Tang ◽  
Jianning Song ◽  
Jamie N Bakkum-Gamez ◽  
Mark E Sherman ◽  
...  

During oncogenesis, pathogenic clones develop which contain cells capable of spreading throughout the body, ultimately compromising vital organ functions and physiology. Understanding how metastatic clones develop and spread is critical for improving cancer treatments. However, our understanding of these processes has been hampered by a paucity of quantitative methodologies to comprehensively map, track and characterize such clones. To address this shortcoming, we have developed a DNA barcoding and next-generation sequencing based system-wide clonal tracking technology integrated with a computational data analysis pipeline called Clone-Initiating Cell (CIC) Calculator. The CIC Calculator interfaces with the CIC Morbus Mandala (CIC-MM) plot, a novel tool to visually comprehend and detect four distinct categories that explains their complex relationships with various tissues/organ sites. Further, we describe machine learning approaches to study CIC number, frequency, and estimate clone size and distribution demonstrating distinct growth patterns, and their inter-relationships and their routes of metastatic spread at clonal resolution. We demonstrate these methodologies, using our novel multifunctional lentiviral barcode libraries, and specifically barcoded tubal-ovarian metastatic OVCAR5 cell lines (engineered to express varying levels of metastasis promoting LRRC15 gene) and co-injected cells in a competitive CIC assay into tubal or ovarian sites in highly immunodeficient NSG mice. DNA was isolated from primary tumors, omental/bowel metastasis and system-wide anatomical site/organs. Amplicon sequencing libraries were constructed with spike-in-control barcodes (serving as internal calibration controls) to estimate absolute clone sizes. The computational pipeline CIC Calculator was then used to deconvolute and filter the data, set stringent thresholds, and generate high-quality information on CIC numbers and frequencies, clone sizes, linkages across sites and classify clones based on their extent of metastatic activity. Using of CIC-MM plot, statistical models and machine learning approaches, we generated high-resolution clonal maps of metastasis for each animal. The information generated included clone types and system-wide metastasis, similar and dissimilar clonal patterns of dominance at heterotopic sites and their routes of metastases. The data revealed previously unknown influences of cellular genotype and their implanted sites on selecting certain clones with specific system-wide clonal patterns, and identified rare LRRC15 expressor clones (classified as CIC.Toti) predisposed to exploit all sites, albeit at varying degrees of dominance. The genomic technology and computational methodology described here are tissue-agnostic. They enable rapid adoption for an investigation into various stages of system-wide metastasis and growth of transplantable malignant cells at the highest clonal resolution.


1964 ◽  
Vol 15 (5) ◽  
pp. 771 ◽  
Author(s):  
BA Panaretto

Ten Border Leicester x Merino ewes were divided into two groups on the basis of a initial calculation of their body composition. Group 1 comprised a group of six moderately fat ewes (fat content < 25% body weight), and group 2 four very fat ewes (fat content >40% body weight). The ewes were undernourished by feeding progressively diminishing quantities of a mixture of lucerne chaff and oats (1:1) until group 1 had lost 38.7 and group 2 33.7% of their initial weight in 150–200 days. Feed intakes and wool growth of the sheep were recorded and calculations were made of the body composition in terms of total body water, fat, protein, and ash as undernutrition progressed. Thiocyanate spaces, haematocrit values, and plasma, blood, and red cell volumes were also measured. Generally the ewes in group 1 exhibited a starvation syndrome which was characterized by the gradual depletion of the fat and protein reserves of the body until fat reserves had been almost completely used. Thiocyanate spaces in these ewes expanded relative to body weight, and the circulatory parameters showed a progressive shrinkage of the red cell volume while plasma volume was maintained. The ewes in group 2 differed markedly in their reaction to undernutrition in that three out of the four passed, after a time, into a phase of inappetence and died while still in a very fat condition.


Parasitology ◽  
1966 ◽  
Vol 56 (4) ◽  
pp. 657-664 ◽  
Author(s):  
Trond Bråten

Investigations on the host specificity of plerocercoids of Schistocephalus solidus were carried out using the technique of surgically transferring plerocercoids from the body cavity of Gasterosteus aculeatus to various other fish. Plerocercoids survived in all cases when transferred from G. aculeatus to other G. aculeatus; when tranferred to Pungitius pungitius the worms survived for long periods but failed to grow. Plerocercoids transferred to Coitus gobio, Nemacheilus barbatula, Phoxinus phoxinus, Salmo trutta, Coregonus clupeoides, Perca fluviatilis, Rutilus rutilus and Esox lucius always died within 2–10 days after being transferred. Electron-microscopic examinations of the tegument of plerocercoids transferred to new hosts showed: in G. aculeatus normal appearance throughout the experiment; in P. pungitius degeneration of the microtrichs after 6 days; and in S. trutta complete destruction of the tegument in 7 days.Plerocercoids of the genus Diphyllobothrium survived the transfer from Gasterosteus aculeatus to Salmo trutta and continued to grow in their new host.Infection of fish with S. solidus by feeding infected copepods and by aspetic injection of procercoids into the body cavity of the fish were also tried. Gasterosteus aculeatus became infected using both these methods but it was not possible to infect Pungitius pungitius.


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