Cortical microtubular structures of the ciliate Lepidotrachelophyllum fornicis Nicholls &Lynn, 1984 and phytogeny of the litostomate ciliates

1985 ◽  
Vol 63 (8) ◽  
pp. 1835-1845 ◽  
Author(s):  
Denis H. Lynn ◽  
Kenneth H. Nicholls

The somatic and oral cortical ultrastructure of Lepidotrachelophyllum fornicis Nicholls &Lynn, 1984 are described. The somatic kinetids are monokinetids whose fibrillar associates include the following: (i) a kinetodesmal fibril which originates near triplets 6, 7, and 8 and extends laterally and to the right at an angle of about 45° to the longitudinal axis of the kinety; (ii) a postciliary ribbon which originates in dense material near triplet 9 and extends posteriorly and to the right; (iii) a primary transverse ribbon which originates near triplets 3, 4, and 5 and extends to the left and anteriorly; (iv) a secondary transverse ribbon which originates near triplet 5 and curves to extend to the lateral left; and (v) a ribbon of rootlet microtubules which originates on the left at the base of the kinetosome. The oral kinetids are dikinetids. The ciliated posterior kinetosome has the following: (i) a postciliary ribbon which extends posteriorly and to the right; and (ii) a transverse ribbon which extends only a short distance anteriorly. The nonciliated anterior kinetosome has the following: (i) a single postciliary microtubule; (ii) a large transverse ribbon which extends into the oral cone; and (iii) near its base a hexagonal nematodesma. The cytopharyngeal apparatus or rhabdos is described and a schematic figure is presented. The cellular mechanisms underlying body shape changes and food vacuole formation and the phylogeny of the class Litostomatea are discussed.


Genetics ◽  
2002 ◽  
Vol 162 (4) ◽  
pp. 1631-1639
Author(s):  
Yo Suzuki ◽  
Gail A Morris ◽  
Min Han ◽  
William B Wood

Abstract The signaling pathway initiated by the TGF-β family member DBL-1 in Caenorhabditis elegans controls body shape in a dose-dependent manner. Loss-of-function (lf) mutations in the dbl-1 gene cause a short, small body (Sma phenotype), whereas overexpression of dbl-1 causes a long body (Lon phenotype). To understand the cellular mechanisms underlying these phenotypes, we have isolated suppressors of the Sma phenotype resulting from a dbl-1(lf) mutation. Two of these suppressors are mutations in the lon-3 gene, of which four additional alleles are known. We show that lon-3 encodes a collagen that is a component of the C. elegans cuticle. Genetic and reporter-gene expression analyses suggest that lon-3 is involved in determination of body shape and is post-transcriptionally regulated by the dbl-1 pathway. These results support the possibility that TGF-β signaling controls C. elegans body shape by regulating cuticle composition.



Author(s):  
Karen S. Young ◽  
K. Han Kim ◽  
Sudhakar Rajulu

Objective This study aims to identify the change in anthropometric measurements during spaceflight due to microgravity exposure. Background Comprehensive and accurate anthropometric measurements are crucial to assess body shape and size changes in microgravity. However, only limited anthropometric data have been available from the astronauts in spaceflight. Methods A new photogrammetry-based technique in combination with a tape-measure method was used for anthropometric measurements from nine crewmembers on the International Space Station. Measurements included circumference and height for body segments (chest, waist, bicep, thigh, calf). The time-dependent variations were also assessed across pre-, in-, and postflight conditions. Results Stature showed a biphasic change with up to 3% increase at the early flight phase, followed by a steady phase during the remaining flight. Postflight measurements returned to a similar level of the preflight. Other linear measurements, including acromion height, showed similar trends. The chest, hip, thigh, and calf circumferences show overall decrease during the flight up to 11%, then returned close to the preflight measurement at postflight. Conclusion The measurements from this study provide critical information for the spacesuit and hardware design. The ground-based assessments for spacesuit fit needs to be revalidated and adjusted for in-flight extravehicular activities from this data. Application These data can be useful for space suit design as well as habitat, vehicle, and additional microgravity activities such as exercise, where the body shape changes can affect fit, performance, and human factors of the overall design.



Author(s):  
Joan C. Lo ◽  
Kathleen Mulligan ◽  
Viva W. Tai ◽  
Heather Algren ◽  
Morris Schambelan
Keyword(s):  


Zootaxa ◽  
2017 ◽  
Vol 4258 (6) ◽  
pp. 581 ◽  
Author(s):  
FRANCIANE CEDROLA ◽  
ROBERTO JÚNIO PEDROSO DIAS ◽  
ISABEL MARTINELE ◽  
MARTA D’AGOSTO

To date the genus Diploplastron comprised only one species of ophryoscolecid ciliate, Diploplastron affine, which is characterized by having two retractable ciliary zones in the anterior end of the body, two slender and juxtaposed skeletal plates on the right side, a rod shape macronucleus, and two contractile vacuoles. During study on the characterization of rumen ciliate community composition in Brazilian domestic sheep, we observed ciliates with atypical morphology but with diagnostic features of genus Diploplastron. This study describes Diploplastron dehorityi, a new species of ophryoscolecid ciliate, that differs from D. affine, primarily, in the morphology of skeletal plates, morphology of nuclear apparatus and body shape. In addition to the similarities between the new species and congener species, D. dehorityi has some morphological similarities to species of genus Eremoplastron.



1974 ◽  
Vol 15 (2) ◽  
pp. 403-406
Author(s):  
ELSE K. HOFFMANN ◽  
L. RASMUSSEN ◽  
E. ZEUTHEN

Cytochalasin B (37 µg per ml) reduces the rate of food vacuole formation, i.e. the rate of phagocytosis, in Tetrahymena pyriformis. Cytochalasin B in this concentration suppresses multiplication rates in a nutrient medium consisting of 2 % proteose peptone, but multiplication is unaffected if this medium is supplemented with glucose and high concentrations of nucleosides. Thus nutrients in high concentrations circumvent the necessity for phagocytosis in Tetrahymena.



Author(s):  
Peter Mitchell

Over 50,000 years ago a Neanderthal hunter approached a wild ass on the plains of northeastern Syria. Taking aim from the right as the animal nervously assessed the threat, he launched his stone-tipped spear into its neck, penetrating the third cervical vertebra and paralyzing it immediately. Butchered at the kill site, this bone and most of the rest of the animal were taken back to the hunter’s camp at Umm el Tlel, a short distance away. Closely modelled on archaeological observations of that vertebra and the Levallois stone point still embedded within it, this incident helps define the framework for this chapter. At the start of the period it covers, human interactions with the donkey’s ancestors were purely a matter of hunting wild prey, but by its end the donkey had been transformed into a domesticated animal. Chapter 2 thus looks at how this process came about, where it did so, and what the evolutionary history of the donkey’s forebears had been until that point. Donkeys and the wild asses that are their closest relatives form part of the equid family to which zebras and horses also belong. Collectively, equids, like rhinoceroses and tapirs, fall within the Perissodactyla, the odd-toed division of hoofed mammals or ungulates. Though this might suggest a close connection with the much larger order known as the Artiodactyla, the even-toed antelopes (including deer, cattle, sheep, and goats), their superficial resemblances may actually reflect evolutionary convergence; some genetic studies hint that perissodactyls are more closely related to carnivores. Like tapirs and rhinoceroses, the earliest equids had three toes, not the one that has characterized them for the past 40 million years. That single toe, the third, now bears all their weight in the form of a single, enlarged hoof with the adjacent toes reduced to mere splints. This switch, and the associated elongation of the third (or central) metapodial linking the toe to the wrist or ankle, is one of the key evolutionary transformations through which equids have passed. A second involves diet since the earliest perissodactyls were all browsers, not grazers like the equids of today.



ESC CardioMed ◽  
2018 ◽  
pp. 44-49
Author(s):  
José M. Pérez-Pomares ◽  
José L. de la Pompa

The heart is the first functional organ of the vertebrate embryo, beginning to beat at around 4 weeks of gestation in humans. Tissue interactions orchestrate the complex patterning, proliferation, and differentiation processes that transform the embryonic cardiac primordium into the adult heart. During heart embryogenesis, cardiac mesoderm progenitor cells originate bilaterally during gastrulation and move rostrally to form the primitive heart tube, which will then loop towards the right and initiate septation to give rise to the mature four-chambered heart. Experimental studies in animal models have revealed the crucial role that a number of highly conserved signalling pathways, involving active molecular cross-talk between adjacent tissues, play in cardiac development, and how the alterations in these signalling mechanisms may cause congenital heart disease affecting the neonate or adult. Here, we describe briefly the knowledge gained on the molecular and cellular mechanisms underlying cardiac chamber and valve development and its implication in disease. This knowledge will ultimately facilitate the design of diagnostic and therapeutic strategies to treat congenital heart disease.



2019 ◽  
Vol 21 (1) ◽  
pp. 65-66
Author(s):  
Sang-Hoon Seol

Double-chambered right ventricle (DCRV) is a cardiac disease of the right ventricular outflow tract obstruction characterized by anomalous muscle bundles that divide the right ventricle into two chambers. It may be also develop over time as an acquired lesion in patients with an abnormally short distance between the moderator band and the pulmonary valve. This report highlights the case of a man with double-chambered right ventricle after ventricular septal defect operation, who presented with syncope J MEDICINE JAN 2020; 21 (1) : 65-66



2007 ◽  
Vol 44 (2) ◽  
pp. 295-300 ◽  
Author(s):  
S. Saghayam ◽  
N. Kumarasamy ◽  
A. J. Cecelia ◽  
S. Solomon ◽  
K. Mayer ◽  
...  


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