Novel life cycle stages of Colpodella sp. (Apicomplexa) identified using Sam-Yellowe’s trichrome stains and confocal and electron microscopy

Author(s):  
Tobili Y. Sam-Yellowe ◽  
Troy A. Getty ◽  
Kush Addepalli ◽  
Aidan M. Walsh ◽  
Alberto R. Williams-Medina ◽  
...  
Parasitology ◽  
2009 ◽  
Vol 137 (1) ◽  
pp. 13-26 ◽  
Author(s):  
H. BOROWSKI ◽  
R. C. A. THOMPSON ◽  
T. ARMSTRONG ◽  
P. L. CLODE

SUMMARYCryptosporidium parvumis a zoonotic protozoan parasite that mainly affects the ileum of humans and livestock, with the potential to cause severe enteric disease. We describe the complete life cycle ofC. parvumin anin vitrosystem. Infected cultures of the human ileocecal epithelial cell line (HCT-8) were observed over time using electron microscopy. Additional data are presented on the morphology, development and behavioural characteristics of the different life-cycle stages as well as determining their time of occurrence after inoculation. Numerous stages ofC. parvumand their behaviour have been visualized and morphologically characterized for the first time using scanning electron microscopy. Further, parasite-host interactions and the effect ofC. parvumon host cells were also visualized. An improved understanding of the parasite's biology, proliferation and interactions with host cells will aid in the development of treatments for the disease.


2002 ◽  
Vol 76 (3) ◽  
pp. 207-215 ◽  
Author(s):  
A.R. Butcher ◽  
J.K. Brealey ◽  
D.I. Grove ◽  
R.B. Dymock

AbstractBrachylaima cribbiis a recently described species of terrestrial trematode that infects mammals and birds with helicid land snails as its first and second intermediate hosts. The adult worm is 2.5–6.0 mm long by 0.5–0.8 mm wide being a long slender cylindrical worm with oral and ventral suckers in the anterior quarter and genital pore in the posterior quarter. Scanning electron microscopy shows that there is a dense covering of tegumental spines at the anterior end which diminishes towards the posterior extremities of the worm. Development of spines was observed in juvenile and mature adult worms. In young worms 1–3 weeks post infection (wpi) spines appear as buds with a serrated edge each having 1–4 spikes per spine. As the worm ages the spines broaden and by 5 wpi the number of spikes per spine increases to an average of 8.1. The serial development of oral sucker papillae in the cercaria, metacercaria and adult worm was observed with the finding of an elongated papilla with a bifurcated tip on the cercaria becoming a shorter and thicker elongated papilla with a large central stoma on the metacercaria. In the adult worm, this papilla becomes dome-shaped with a small central stoma. For some of these papillae a cilium could be seen extended from the central stoma. Other life-cycle stages illustrated were the hatched egg with an extruded egg membrane minus an operculum and a portion of the branched sporocyst dissected from the digestive gland of the land snailTheba pisanashowing a terminal birth pore. Scanning electron microscopy morphological features of the adult worm observed for the first time in aBrachylaimawere the unarmed cirrus extended from the genital pore with released sperm present and the Laurer's canal opening visible in tegumental folds on the dorsal surface approximately 300 μm posterior to the genital pore.


2020 ◽  
Author(s):  
Joost de Vries ◽  
Fanny Monteiro ◽  
Glen Wheeler ◽  
Alex Poulton ◽  
Jelena Godrijan ◽  
...  

Abstract. Coccolithophores are globally important marine calcifying phytoplankton that utilize a haplo-diplontic life cycle. The haplo-diplontic life cycle allows coccolithophores to divide in both life cycle phases, and has been proposed to allow coccolithophores to expand their niche space. To-date research has however largely overlooked the life cycle of coccolithophores, and has instead focused on the diploid life cycle phase. Through a synthesis of global scanning electron microscopy (SEM) coccolithophore abundance data (n = 2534), we show that the haploid life cycle phase contributes significantly to coccolithophore abundance, constituting ≈18 % of species abundance for which haploid-diploid pairs are defined. Using hypervolumes to quantify the niche space of coccolithophores, we furthermore show that the haploid and diploid life cycle phases inhabit contrasting niches, and that this allows coccolithophores to expand their niche space by ≈17 %. Our results highlight that future coccolithophore research should consider both life cycle stages, as omission of the haploid life cycle phase in current research limits our understanding of coccolithophore ecology.


2009 ◽  
Vol 83 (4) ◽  
pp. 321-331 ◽  
Author(s):  
S. Pina ◽  
J. Tajdari ◽  
F. Russell-Pinto ◽  
P. Rodrigues

AbstractDiphtherostomum brusinae was first recorded by the present study in the north of Portugal. Sporocysts, containing cercariae and encysted metacercariae, were observed in the gonads and digestive gland of the gastropod Nassarius reticulatus. Metacercariae were also found infecting the foot, mantle border and gills of the cockle Cerastoderma edule. The adult form was lodged in the rectum of the definitive host Diplodus sargus. The morphology of the three parasitic stages was studied by light (LM) and scanning electron microscopy (SEM). Despite the close similarity between cercaria and metacercaria, SEM data provided information that allowed their differentiation, namely the presence of a dense crown of microvilli around the oral cavity of the cercariae, which was absent in the metacercariae. In addition, the metacercariae presented a specific pre-acetabular rectangular band with conspicuous triangular spines. The adult showed characteristics of D. brusinae species, in particular the presence of acetabular lips, compact vitellaria and large elliptical eggs. Sequenced ITS1 data clearly demonstrated that the cercariae and metacercarial cysts from N. reticulatus, the cysts from C. edule and the adult isolated from D. sargus were life cycle stages that belonged to the same species, i.e. D. brusinae. Two transmission strategies in the life cycle of this species were observed: (1) cercariae encyst within the sporocysts of N. reticulatus and await ingestion by the definitive host; and (2) N. reticulatus naturally emits cercariae; they encyst in C. edule or the environment and are ingested by the definitive host.


2019 ◽  
Vol 0 (3) ◽  
pp. 53-60 ◽  
Author(s):  
T.Yu. Altufyeva ◽  
◽  
P.A. Ivanov ◽  
G.R. Sakhapova ◽  
◽  
...  

2009 ◽  
Vol 66 (1) ◽  
Author(s):  
Susana Gómez-González ◽  
Lohengrin A Cavieres ◽  
Patricio Torres ◽  
Cristian Torres-Díaz

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3287
Author(s):  
Alireza Tabrizikahou ◽  
Piotr Nowotarski

For decades, among other industries, the construction sector has accounted for high energy consumption and emissions. As the energy crisis and climate change have become a growing concern, mitigating energy usage is a significant issue. The operational and end of life phases are all included in the building life cycle stages. Although the operation stage accounts for more energy consumption with higher carbon emissions, the embodied stage occurs in a time-intensive manner. In this paper, an attempt has been made to review the existing methods, aiming to lower the consumption of energy and carbon emission in the construction buildings through optimizing the construction processes, especially with the lean construction approach. First, the energy consumption and emissions for primary construction materials and processes are introduced. It is followed by a review of the structural optimization and lean techniques that seek to improve the construction processes. Then, the influence of these methods on the reduction of energy consumption is discussed. Based on these methods, a general algorithm is proposed with the purpose of improving the construction processes’ performance. It includes structural optimization and lean and life cycle assessments, which are expected to influence the possible reduction of energy consumption and carbon emissions during the execution of construction works.


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