Regional specializations of the tegument of the metacercaria ofTimoniella imbutiforme

2000 ◽  
Vol 74 (1) ◽  
pp. 67-72 ◽  
Author(s):  
H.E.M. El-Darsh ◽  
P.J. Whitfield
Keyword(s):  
Oral Sucker ◽  
Outer Surface ◽  
Single Type ◽  
Apical Surface ◽  
Secretory Body ◽  
First Time

AbstractThe ultrastructure of the spinous body tegument of the metacercaria ofTimoniella imbutiforme(Molin, 1859) has recently been described. Other regions of the metacercarial tegument, including those of the oral sucker, pharynx, and nephridiopore, demonstrate considerable specializations. The oral sucker tegument had an aspinous outer syncytial layer that possessed a pimpled apical surface as well as enclosing two types of secretory bodies. The pharyngeal tegument likewise lacked spines, but possessed only one type of secretory body, and a smooth but folded outer surface. The nephridiopore tegument, however, showed the greatest degree of specialization possessing a single type of secretory body specific only to this region of the tegument. Also associated with the syncytium here was a prominent long filamentous glycocalyx, and microtubules which were observed for the first time in this region of the tegument.

Ultrastructural observations on the redial tegument of Paramphistomum epiclitum from the planorbid snail, Indoplanorbis exustus

1992 ◽  
Vol 66 (3) ◽  
pp. 167-176 ◽  
Author(s):  
T. S. Dunn ◽  
P. H. Dang ◽  
G. Mattison ◽  
R. E. B. Hanna ◽  
W. A. Nizami
Keyword(s):  
Outer Surface ◽  
Apical Membrane ◽  
Single Type ◽  
Sensory Receptors ◽  
Secretory Body ◽  
Indoplanorbis Exustus ◽  
Paramphistomum Epiclitum ◽  
Single Nucleus ◽  
Uptake Of Nutrients ◽  
Tegumental Syncytium

ABSTRACTThe morphology of the tegument in the redia of Paramphistomum epiclitum (Digenea: Paramphistomidae) resembles that shown by most larval and adult digeneans; an outer surface syncytium is in continuity with the cytoplasm of in-sunken, nucleated cytons. Although tegumental cytons usually contain a single nucleus, some display up to six nuclei. The tegumental syncytium lining the pharynx of P. epiclitum rediae lack underlying cytons. The apical membrane of the tegument is elaborated by folds and microvilli, which presumably facilitate uptake of nutrients and/or exchange of ions involved in osmoregulation. A single type of secretory body, resulting from the fusion of smaller vesicles produced at Golgi complexes in the cytons, occurs throughout the tegument. Uniciliate sensory receptors occur in the surface syncytium particularly around the oral opening.

scholarly journals First record of a parasitoid, Megaselia (M) scalaris (Diptera: Phoridae) of fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) from India

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Sharanabasappa S. Deshmukh ◽  
S. Kiran ◽  
Atanu Naskar ◽  
Palam Pradeep ◽  
C. M. Kalleshwaraswamy ◽  
...  
Keyword(s):  
Outer Surface ◽  
Spodoptera Frugiperda ◽  
Fall Armyworm ◽  
First Record ◽  
Instar Larva ◽  
Major Threat ◽  
Megaselia Scalaris ◽  
Maize Cultivation ◽  
First Time ◽  
Lepidoptera Noctuidae

AbstractThe fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), has become a major threat in maize cultivation since its invasion to India in 2018. The humpbacked fly, Megaselia scalaris (Loew) (Diptera: Phoridae), was recorded as a laboratory parasitoid of FAW, for the first time in India. Initially, 30–40 maggots of M. (M) scalaris emerged out from the dead pre-pupa and pupa of laboratory-reared FAW. The fly laid up to 15 eggs on the outer surface of 6th instar larva or pre-pupa of the FAW. The incubation period was 1–2 days. The fly had 3 larval instars which lasted 3–4 days and a pupal period of 10–11 days. The adults survived for 6–7 days.

Fistulicola plicatus (Cestoda) and Tristoma spp. (Trematoda) on Swordfish from the Northwest Atlantic

1971 ◽  
Vol 28 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Christine Iles
Keyword(s):  
Body Length ◽  
Outer Surface ◽  
Northwest Atlantic ◽  
Xiphias Gladius ◽  
First Time ◽  
Biological Tags

Data on the incidence, location, and morphology of the scolex of Fistulicola plicatus in 24 specimens of swordfish (Xiphias gladius) from the northwest Atlantic are given. The occurrence of normal scolices in tubular sheaths or bladderlike cysts on the outer surface of the rectum is recorded for the first time for this species. The incidence and location on the gills of Tristoma coccineum and T. integrum are given and the possibility of using these monogenetic trematodes as biological tags is discussed. The increase in the number of dorsomarginal rows of comb teeth with body length for immature specimens of T. coccineum is demonstrated.

scholarly journals Coalescence in Subcritical Bellman-Harris Age-Dependent Branching Processes

2013 ◽  
Vol 50 (2) ◽  
pp. 576-591
Author(s):  
Jyy-I Hong
Keyword(s):  
Limit Distribution ◽  
Branching Process ◽  
Branching Processes ◽  
Simple Random Sampling ◽  
Single Type ◽  
Last Common Ancestor ◽  
Death Time ◽  
Age Dependent ◽  
Lines Of Descent ◽  
First Time

We consider a continuous-time, single-type, age-dependent Bellman-Harris branching process. We investigate the limit distribution of the point process A(t)={at,i: 1≤ i≤ Z(t)}, where at,i is the age of the ith individual alive at time t, 1≤ i≤ Z(t), and Z(t) is the population size of individuals alive at time t. Also, if Z(t)≥ k, k≥2, is a positive integer, we pick k individuals from those who are alive at time t by simple random sampling without replacement and trace their lines of descent backward in time until they meet for the first time. Let Dk(t) be the coalescence time (the death time of the last common ancestor) of these k random chosen individuals. We study the distribution of Dk(t) and its limit distribution as t→∞.

Coalescence in Subcritical Bellman-Harris Age-Dependent Branching Processes

2013 ◽  
Vol 50 (02) ◽  
pp. 576-591 ◽  
Author(s):  
Jyy-I Hong
Keyword(s):  
Limit Distribution ◽  
Branching Process ◽  
Branching Processes ◽  
Simple Random Sampling ◽  
Single Type ◽  
Last Common Ancestor ◽  
Death Time ◽  
Age Dependent ◽  
Lines Of Descent ◽  
First Time

We consider a continuous-time, single-type, age-dependent Bellman-Harris branching process. We investigate the limit distribution of the point process A(t)={a t,i : 1≤ i≤ Z(t)}, where a t,i is the age of the ith individual alive at time t, 1≤ i≤ Z(t), and Z(t) is the population size of individuals alive at time t. Also, if Z(t)≥ k, k≥2, is a positive integer, we pick k individuals from those who are alive at time t by simple random sampling without replacement and trace their lines of descent backward in time until they meet for the first time. Let D k(t) be the coalescence time (the death time of the last common ancestor) of these k random chosen individuals. We study the distribution of D k(t) and its limit distribution as t→∞.

scholarly journals Isolation and Characterization of a New Subtype of Borna Disease Virus

2000 ◽  
Vol 74 (12) ◽  
pp. 5655-5658 ◽  
Author(s):  
Norbert Nowotny ◽  
Jolanta Kolodziejek ◽  
Christian O. Jehle ◽  
Angelika Suchy ◽  
Peter Staeheli ◽  
...  
Keyword(s):  
Disease Virus ◽  
Single Type ◽  
The Novel ◽  
Borna Disease Virus ◽  
Diagnostic Assays ◽  
Isolation And Characterization ◽  
First Time ◽  
Reference Strains ◽  
Borna Disease

ABSTRACT Borna disease virus (BDV), the causative agent of severe meningoencephalitis in a wide variety of animal species, has been considered to be genetically invariable and to form a single type within the genus Bornavirus of the familyBornaviridae. BDV infections are of particular interest, because for the first time a virus infection appears to be linked to human psychiatric disorders. We now describe a new subtype of BDV isolated from a horse which was euthanatized due to severe, incurable neurological disease. The nucleotide sequence of this new strain, named No/98, differs from the reference strains by more than 15%, and the subtype is difficult to detect by standard reverse transcriptase PCR protocols. The nucleotide exchanges of the novel BDV isolate have surprisingly little effect on the primary structures of most viral proteins, with the notable exception of the X protein (p10), which is only 81% identical to its counterpart in reference strains. Our data indicate that the genome of BDV is far more variable than previously assumed and that naturally occurring subtypes may escape detection by currently used diagnostic assays.

scholarly journals Desmoplakin is required for epidermal integrity and morphogenesis in the Xenopus laevis embryo

2018 ◽  
Author(s):  
Navaneetha Krishnan Bharathan ◽  
Amanda J.G. Dickinson
Keyword(s):  
Cell Types ◽  
Secretory Cells ◽  
Apical Surface ◽  
Developmental Defects ◽  
Summary Statement ◽  
Epidermal Morphogenesis ◽  
Cytoskeletal Elements ◽  
First Time ◽  
Desmosomal Protein ◽  
E Cadherin

AbstractDesmoplakin (Dsp) is a unique and critical desmosomal protein, however, it is unclear whether this protein and desmosomes themselves are required for epidermal morphogenesis. Using morpholinos or Crispr/Cas9 mutagenesis we decreased the function of Dsp in frog embryos to better understand its role during epidermal development. Dsp morphant and mutant embryos had developmental defects that mimicked what has been reported in mammals. Such defects included epidermal fragility which correlated with reduction in cortical keratin and junctional e-cadherin in the developing epidermis. Dsp protein sequence and expression are also highly similar with mammals and suggest shared function across vertebrates. Most importantly, we also uncovered a novel function for Dsp in the morphogenesis of the epidermis in X. laevis. Specifically, Dsp is required during the process of radial intercalation where basally located cells move into the outer epidermal layer. Once inserted these newly intercalated cells expand their apical surface and then they differentiate into specific epidermal cell types. Decreased levels of Dsp resulted in the failure of the radially intercalating cells to expand their apical surface, thereby reducing the number of differentiated multiciliated and secretory cells. Dsp is also required in the development of other ectodermally derived structures such as the mouth, eye and fin that utilize intercalating-like cell movements. We have developed a novel system, in the frog, to demonstrate for the first time that desmosomes not only protect against mechanical stress but are also critical for epidermal morphogenesis.Summary StatementCritical desmosomal protein, desmoplakin, is required for proper distribution and levels of cytoskeletal elements and e-cadherin. Thus embryos with decreased desmoplakin have defects in epidermal integrity and morphogenesis.

Dispersion-Assisted Tunable Fluorescence from Carbon Dots

2022 ◽  
Author(s):  
Qian He ◽  
Junkai Ren ◽  
Yaodong Liu
Keyword(s):  
Carbon Dots ◽  
Fluorescence Emission ◽  
Single Type ◽  
Visible Range ◽  
Double Stranded Dna ◽  
Comprehensive Comparison ◽  
Novel Strategy ◽  
Induced Aggregation ◽  
First Time ◽  
Internal Absorption

Abstract In this study, carbon dots (CDs) synthesized by hydrothermal method with amino-rich surface exhibit tunable fluorescence across entire visible range by simply controlling the concentration. A comprehensive comparison has been performed for the first time between concentration-induced aggregation of the single-type CDs and electrostatic-induced agglomeration of opposite-charged CDs in terms of their fluorescence properties. Experimental results show that both the aggregation of CDs and internal absorption filtration are possible causes of the concentration-dependent fluorescence emission. Subsequently, the inter distance of adjacent CDs in their aggregates was enlarged by forming rigid double-stranded DNA (dsDNA) between adjacent CDs through base pairing. It is clear that the contact of CDs induces the changes of fluorescence emission and light absorption. Through a better understanding of the mechanisms behind concentration-induced multicolor emission, this work can provide a novel strategy to develop the advanced applications of CDs.

Cercaria vaullegeardi Pelseneer, 1906 (Digenea: Hemiuridae); development and ultrastructure

Parasitology ◽  
1981 ◽  
Vol 83 (3) ◽  
pp. 575-586 ◽  
Author(s):  
B. F. Matthews
Keyword(s):  
Secretory Cell ◽  
Developmental Stages ◽  
Ultrastructural Level ◽  
Mantle Cavity ◽  
Single Type ◽  
Scanning Electron Micrographs ◽  
Delivery Tube ◽  
First Time ◽  
Caudal Gland ◽  
Electron Lucent

SUMMARYCercaria vaullegeardi develops in daughter sporocysts within the digestive gland of the prosobranch Gibbula umbilicalis. On emergence into the host mantle cavity the cercarial body retracts into the cystophorous tail, the ‘encysted’ cercaria being then shed into the sea. The encysted cercaria is described at the ultrastructural level for the first time and developmental stages are redescribed. The cercarial body has no penetration or cystogenous glands: a single type of sub-tegumental secretory cell produces vesicles containing neutral mucopolysaccharides which pass into the tegument at encystment. The immotile cystophorous tail consists essentially of a fibrous caudal cyst and 8 appendages including a delivery tube. Scanning electron micrographs show the surface of tegumental membranes enveloping the caudal cyst to be covered with a honeycomb pattern of indentations derived from electron-lucent vesicles produced by the caudal gland. The fibrous-walled delivery tube comprises proximal and distal sections and a modified terminal end-piece.

scholarly journals Lubiprostone stimulates secretion from tracheal submucosal glands of sheep, pigs, and humans

2009 ◽  
Vol 296 (5) ◽  
pp. L811-L824 ◽  
Author(s):  
N. S. Joo ◽  
J. J. Wine ◽  
A. W. Cuthbert
Keyword(s):  
Short Circuit ◽  
Short Circuit Current ◽  
Gland Secretion ◽  
Single Type ◽  
Surface Epithelium ◽  
Chronic Obstructive ◽  
Apical Surface ◽  
Submucosal Gland ◽  
Anion Secretion ◽  
Secretion Rates

Lubiprostone, a putative ClC-2 chloride channel opener, has been investigated for its effects on airway epithelia (tracheas). Lubiprostone is shown to increase submucosal gland secretion in pigs, sheep, and humans and to increase short-circuit current (SCC) in the surface epithelium of pigs and sheep. Use of appropriate blocking agents and ion-substitution experiments shows anion secretion is the driving force for fluid formation in both glands and surface epithelium. From SCC concentration-response relations, it is shown that for apical lubiprostone Kd = 10.5 nM with a Hill slope of 1.08, suggesting a single type of binding site and, from the speed of the response, close to the apical surface, confirmed the rapid blockade by Cd ions. Responses to lubiprostone were reversible and repeatable, responses being significantly larger with ventral compared with dorsal epithelium. Submucosal gland secretion rates following basolateral lubiprostone were, respectively, 0.2, 0.5, and 0.8 nl gl−1 min−1 in humans, sheep, and pigs. These rates dwarf any contribution surface secretion adds to the accumulation of surface liquid under the influence of lubiprostone. Lubiprostone stimulated gland secretion in two out of four human cystic fibrosis (CF) tissues and in two of three disease controls, chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis (COPD/IPF), but in neither type of tissue was the increase significant. Lubiprostone was able to increase gland secretion rates in normal human tissue in the continuing presence of a high forskolin concentration. Lubiprostone had no spasmogenic activity on trachealis muscle, making it a potential agent for increasing airway secretion that may have therapeutic utility.

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