News Letter on Cestode Research: April – 2019

Estimating effective population size for a cestode parasite infecting three-spined sticklebacks

Remarkably few makes an attempt are created to estimate modern effective population size (Ne) for parasitic species, despite the dear views it can give on the tempo and pace of parasite evolution likewise as coevolutionary dynamics of host–parasite interactions. during this study, we tend to utilised multi-locus microsatellite knowledge to derive single-sample and temporal estimates of up to date Ne for a tapeworm parasite (Schistocephalus solidus) likewise as prickleback hosts (Gasterosteus aculeatus) in lakes across Alaska. in keeping with previous studies, each approaches recovered tiny and extremely variable estimates of parasite and host Ne. we tend to additionally found that estimates of host Ne and parasite Ne were sensitive to assumptions regarding population genetic structure and property. And, whereas previous work on the spiny-finned fish–cestode system indicates that physiographic factors external to stickleback hosts mostly govern genetic variation in S. solidus, our findings indicate that spiny-finned fish host attributes and factors internal to the host – particularly linear unit, genetic diversity and infection – form modern Ne of tapeworm parasites. [1]

Two new cestode species of the family Hymenolepididae Perrier, 1897 (Cyclophyllidea) from passerine birds in Ethiopia, with the erection of Citrilolepis n. g.

Two new flatworm species of the family Hymenolepididae Perrier, 1897 are delineate from birds of the animal order at Wondo Genet, Ethiopia. Passerilepis zimbebel n. sp., a parasite of Terpsiphone viridis (Müller) (Monarchidae), is distinguished from its most similar congeners by its diorchoid rostellar hooks with length 37–38 μm, its median ovary consisting of 3 compact lobes, its compact vitellarium and therefore the variable position of the terminal venereal ducts passing largely dorsally to the poral osmoregulatory canals. Citrilolepis n. g. is erected as taxon for C. citrili n. sp., a parasite of Crithagra citrinelloides (Rüpell) (Fringillidae). The new genus is distinguished from the remaining vertebrate and class genera of the family Hymenolepididae by the presence of various (18) rostellar hooks, unilateral sinistral venereal pores, ventral osmoregulatory canals with thwartwise anastomoses, three (rarely four, in c.10% of proglottides) testes in range with variable positions within the proglottis and therefore the sac-like womb not extending on the far side the osmoregulatory canals. [2]

Transcriptomic profile of two developmental stages of the cestode parasite Mesocestoides corti

Cestode development involves complicated morphological and physiological changes. Here, we tend to performed a differential expression analysis of sequence transcripts between 2 biological process stages of the model flatworm Mesocestoides corti. A RNA-seq-based approach was accustomed compare the transcriptomes of the tetrathyridium (larval, TT) and strobilated worm (ST) stages of the parasite. we tend to found nineteen,053 transcripts, from that ∼45% were complete matches to genes antecedently annotated within the on the market M. corti draft order sequence, ∼24% were thought-about novel isoforms, and ∼24% were thought-about potential novel transcripts. Stage-specific transcripts were found for each TTs (66) and STs (136), together with shared transcripts considerably overrepresented in one stage (342 in TTs, and 559 in STs). Differential expression and sequence metaphysics term enrichment analyzes provided proof of upregulation of various sets of transcripts related to ‘cytoskeleton’, ‘metabolism’ and ‘oxidation-reduction’ processes in every stage, suggesting purposeful involvement of the corresponding genes with stage-specific options. Transcripts and processes enriched within the TT mirror typical larval processes that occur with the parasite in the host, like agamogenesis and budding, yet as active migration from the serosa to the liver and the other way around. In STs, transcripts related to ‘development’, ‘cell growth’, and ‘morphogenesis’ were enriched, together with processes associated with reproduction, delineated  by the upregulation of various transcription factors, supermolecule kinases, and histones. Overall, our results contributed to considerably increase the data on the M. cortigene repertoire and expression profile in 2 biological process stages. purposeful implications for the biology of larval and adult flatworm parasites and for host-parasite interactions are mentioned. [3]

Maturation Divisions of the Ova in the Pseudophyllidean Cestode, Eubothrium crassum (Bloch)

MUCH confusion still exists in generalized accounts of life-histories of parasitic Platyhelminthes regarding the position of the egg at the time of its maturation divisions and so regarding the precise time of fertilization. Indeed, it’s been suggested1 that standard ontogeny doesn’t occur in several cestodes of the Cyclophyllidea, Tetraphyllidea and Trypanorhyncha. in an exceedingly range of digenetic trematodes, on the opposite hand, it’s been fastidiously shown by numerous staff, notably Chen2, Rees3, Stephenson4 and Willmott5, that meiosis within the egg cell is traditional and happens in this a part of the womb straightaway on the far side the central chamber of Mehlis’s secretory organ. The ova go into the womb at this time encircled by nutrient cells and start maturation divisions without delay whereas the shell is being set down round the egg advanced, that includes one egg cell, nutrient cells and spermatozoa. [4]

Aspects of the Ecology of Proteocephalid Cestode Parasites of Hoplobatrachus tigerinus (Daudin, 1803) and Duttaphrynus melanostictus (Schneider, 1799) from YSR (Kadapa) District, Andhra Pradesh, India

Aspects of the Ecology of Proteocephalid flatworm Parasites of Hoplobatrachus tigerinus (Daudin, 1803) and Duttaphrynus melanostictus (Schneider, 1799) from YSR (Kadapa) District, province, India

The Indian bull frog, Hoplobatrachus tigerinus Daudin, 1803 and Asian common batrachian, Duttaphrynus melanostictus Schneider, 1799 are oftentimes found to be infected with the proteocephalid cestodes. The seasonal dynamics of the Proteocephalus sp. was studied in each amphibians throughout February, 2013 to Gregorian calendar month, 2015 from YSR (Kadapa) District, province. Of the entire 300H. tigerinus examined, solely eighteen frogs (6%) were infected with the flatworm, Proteocephalus tigrinus and of the forty six D. Melanostictus examined, solely fifteen frogs (32.6%) were found to be infected with Proteocephalus sp. Intensity of infection ranged from one to 11(n=31) in H. tigerinus and one to two  (n= 19) in D. melanostictus. Monthly population dynamics of cestodesof H. tigerinus and D. melanostictus were analysed in terms of prevalence, mean intensity, mean abundance and index of infection. The impact of surroundings predilection and therefore the impact of season on the parasitic load were analysed. The impact of host size and sex on the intensity of infection was additionally studied. [5]

Reference

[1] Strobel, H.M., Hays, S.J., Moody, K.N., Blum, M.J. and Heins, D.C., 2019. Estimating effective population size for a cestode parasite infecting three-spined sticklebacks. Parasitology, pp.1-14. (Web Link)

[2] Dimitrova, Y.D., Georgiev, B.B., Mariaux, J. and Vasileva, G.P., 2019. Two new cestode species of the family Hymenolepididae Perrier, 1897 (Cyclophyllidea) from passerine birds in Ethiopia, with the erection of Citrilolepis ng. Systematic parasitology, pp.1-19. (Web Link)

[3] Basika, T., Paludo, G.P., Araujo, F.M., Salim, A.C., Pais, F., Maldonado, L., Macchiaroli, N., de Lima, J.C., Rosenzvit, M., Oliveira, G.C. and Kamenetzky, L., 2019. Transcriptomic profile of two developmental stages of the cestode parasite Mesocestoides corti. Molecular and biochemical parasitology, 229, pp.35-46. (Web Link)

[4] Maturation Divisions of the Ova in the Pseudophyllidean Cestode, Eubothrium crassum (Bloch)

DILYS RAWSON
Nature volume 176, page 167 (1955) (Web Link)

[5] Aspects of the Ecology of Proteocephalid Cestode Parasites of Hoplobatrachus tigerinus (Daudin, 1803) and Duttaphrynus melanostictus (Schneider, 1799) from YSR (Kadapa) District, Andhra Pradesh, India

Mannela Hemalatha
Department of Zoology, Yogi Vemana University, Kadapa, 516 003, India

C. Srinivasa Kalyan
Department of Zoology, Yogi Vemana University, Kadapa, 516 003, India

Anuprasanna Vankara
Department of Zoology, Yogi Vemana University, Kadapa, 516 003, India (Web Link)