Fine structure of the phasmid of second-stage juveniles of Heterodera schachtii (Tylenchida: Nematoda)

1985 ◽  
Vol 63 (3) ◽  
pp. 534-542 ◽  
Author(s):  
James G. Baldwin
Keyword(s):  
Phylogenetic Analysis ◽  
Fine Structure ◽  
Comparative Morphology ◽  
Heterodera Schachtii ◽  
Sheath Cell ◽  
Second Stage ◽  
Plant Parasite ◽  
Junctional Complexes ◽  
And Function ◽  
Cell Sheath

The phasmid of infective second-stage juveniles of Heterodera schachtii consists of an external pore, cuticle-lined duct, socket cell, sheath cell, and single dendrite receptor. Specimens vary in detail and two discrete types, designated A and B, can be distinguished, with A being larger and relatively more complex. In both types of phasmids the socket cell is roughly cup shaped, envelops the duct, and partially encloses and forms junctional complexes with the sheath cell. The sheath cell fills the cup of the socket cell and occurs near the proximal end of the duct. In the A phasmid the sheath cell is deeply invaginated, forming a receptor cavity which is continuous with a maze of extracellular channels penetrating the cell; secretions accumulate in the channels and receptor cavity. Conversely, the sheath cell of the B phasmid lacks a receptor cavity and is nonsecretory. The sheath cell of both types of phasmid encloses and forms junctional complexes with a single dentritic process. In the A phasmid the process terminates within the receptor cavity whereas in the B type the tip is embedded within the sheath cell. A typical basal body or rootlets were not observed, although a ciliary region with a circle of eight doublets surrounding three or four singlets occurs slightly proximal to the terminus. Knowledge of phasmid structure of H. schachtii provides a basis for study of phasmid development and function in a plant parasite; it also contributes to understanding comparative morphology for phylogenetic analysis of Heteroderidae.

Pituitary Follicular Cells: Their Origin, Possible Function and Fate

1974 ◽  
Vol 32 ◽  
pp. 34-35
Author(s):  
E. Horvath ◽  
K. Kovacs ◽  
G. Penz ◽  
C. Ezrin
Keyword(s):  
Fine Structure ◽  
Secretory Granules ◽  
Follicular Cells ◽  
Human Pituitary ◽  
Rat Pituitary ◽  
Pituitary Glands ◽  
Junctional Complexes

Follicular structures, in the rat pituitary, composed of cells joined by junctional complexes and possessing few organelles and few, if any, secretory granules, were first described by Farquhar in 1957. Cells of the same description have since been observed in several species including man. The importance of these cells, however, remains obscure. While studying human pituitary glands, we have observed wide variations in the fine structure of follicular cells which may lead to a better understanding of their morphogenesis and significance.

A Family of Genes Clustered at the Triplo-lethal Locus of Drosophila melanogaster Has an Unusual Evolutionary History and Significant Synteny With Anopheles gambiae

Genetics ◽  
2003 ◽  
Vol 165 (2) ◽  
pp. 613-621 ◽  
Author(s):  
Douglas R Dorer ◽  
Jamie A Rudnick ◽  
Etsuko N Moriyama ◽  
Alan C Christensen
Keyword(s):  
Phylogenetic Analysis ◽  
Drosophila Melanogaster ◽  
Anopheles Gambiae ◽  
Evolutionary History ◽  
Codon Bias ◽  
Good Target ◽  
The Family ◽  
Genes Encoding ◽  
And Function ◽  
Gambiae Genome

Abstract Within the unique Triplo-lethal region (Tpl) of the Drosophila melanogaster genome we have found a cluster of 20 genes encoding a novel family of proteins. This family is also present in the Anopheles gambiae genome and displays remarkable synteny and sequence conservation with the Drosophila cluster. The family is also present in the sequenced genome of D. pseudoobscura, and homologs have been found in Aedes aegypti mosquitoes and in four other insect orders, but it is not present in the sequenced genome of any noninsect species. Phylogenetic analysis suggests that the cluster evolved prior to the divergence of Drosophila and Anopheles (250 MYA) and has been highly conserved since. The ratio of synonymous to nonsynonymous substitutions and the high codon bias suggest that there has been selection on this family both for expression level and function. We hypothesize that this gene family is Tpl, name it the Osiris family, and consider possible functions. We also predict that this family of proteins, due to the unique dosage sensitivity and the lack of homologs in noninsect species, would be a good target for genetic engineering or novel insecticides.

Review: Sperm: Comparative morphology and function related to altered reproductive strategies and fertility in mammals

2018 ◽  
Vol 34 (6) ◽  
pp. 558-565
Author(s):  
Shannon Kate Thompson ◽  
Naseer A. Kutchy ◽  
Samantha Kwok ◽  
Zulfi N.A. Rosyada ◽  
Ikhide G. Imumorin ◽  
...  
Keyword(s):  
Reproductive Strategies ◽  
Comparative Morphology ◽  
And Function

scholarly journals Nuclear receptor nhr-48 is required for pathogenicity of the second stage (J2) of the plant parasite Meloidogyne incognita

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Chao-Jun Lu ◽  
Bao-Yu Tian ◽  
Yi Cao ◽  
Cheng-Gang Zou ◽  
Ke-Qin Zhang
Keyword(s):  
Nuclear Receptor ◽  
Meloidogyne Incognita ◽  
Second Stage ◽  
Plant Parasite

The Biology of Bothrimonus (=Diplocotyle) (Pseudophyllidea: Cestoda): Detailed Morphology and Fine Structure

1974 ◽  
Vol 31 (2) ◽  
pp. 147-153 ◽  
Author(s):  
M. D. B. Burt ◽  
I. M. Sandeman
Keyword(s):  
Electron Microscopy ◽  
Nervous System ◽  
Fine Structure ◽  
Functional Morphology ◽  
Light And Electron Microscopy ◽  
Nerve Fibers ◽  
Fish Host ◽  
Extensive System ◽  
And Function

Light and electron microscopy were used to describe the functional morphology of Bothrimonus sturionis in detail. In particular, the musculature, nervous system, osmoregulatory system, and tegument are dealt with, and the findings compared with those of other workers. The musculature of the scolex consists of several interrelated systems, the structure of each being discussed in relation to its function. Associated with the regular nervous system, considered typical of cestodes, is an extensive system of giant nerve fibers. The osmoregulatory system is unusual in that there are lateral "excretory" pores in many proglottides which open directly to the exterior of the worm. The microtriches of the tegument are long, like those of other primitive cestodes, and are covered by a noncellular sheath while the worm is in its gammarid host. The sheath is lost when the worm becomes established in its fish host; the nature and function of the sheath are discussed.

Para leer la espiritualidad de Agustín. Elementos espirituales

Augustinus ◽  
2020 ◽  
Vol 65 (1) ◽  
pp. 53-78
Author(s):  
Vittorino Grossi ◽  
Keyword(s):  
Holy Spirit ◽  
Saint Augustine ◽  
Second Stage ◽  
Before And After ◽  
The Holy Spirit ◽  
And Function ◽  
Role And Function

The article deals with the key ideas to understand S. Augustine’s Spirituality, setting in its context the figure of the postconstatinian saint, and discussing the topic of the degrees of sanctity in Saint Augustine. Later, it deals with the various spiritual phases in the writings of Saint Augustine, dividing the life of the doctor of Hippo in two moments, before and after his priestly ordination, pointing out in the second stage the role and function of the Holy Spirit as love and principle of holiness. The importance of spiritual man in the period of the anti-Pelagian struggle is also revealed. It also explains what is for Saint Augustine the spirituality of the heart.

Comparative morphology of extant raptorial Mantispoidea (Neuroptera: Mantispidae, Rhachiberothidae) suggests a non-monophyletic Mantispidae and a single origin of the raptorial condition within the superfamily

Zootaxa ◽  
2021 ◽  
Vol 4992 (1) ◽  
pp. 1-89
Author(s):  
ADRIAN ARDILA-CAMACHO ◽  
CALEB CALIFRE MARTINS ◽  
ULRIKE ASPÖCK ◽  
ATILANO CONTRERAS-RAMOS
Keyword(s):  
Phylogenetic Analysis ◽  
Comparative Morphology ◽  
Sister Group ◽  
Sister Group Relationship ◽  
Wing Venation ◽  
Morphological Studies ◽  
Starting Point ◽  
The Family ◽  
Evolutionary Context ◽  
New Interpretation

Adult external morphology of the extant raptorial Mantispoidea (Insecta: Neuroptera: Mantispidae and Rhachiberothidae) is compared emphasizing the morphology of the subfamily Symphrasinae as a key group to understand the phylogenetic relationships among the members of the superfamily. Plega dactylota Rehn, 1939 is thoroughly characterized in order to exemplify the morphology of the Symphrasinae. Additionally, following a review of the literature and examination of comparative material of Dilaridae, Berothidae, Rhachiberothidae and all Mantispidae subfamilies, a new interpretation of the components of the raptorial apparatus (i.e., head, prothorax, grasping forelegs, as well as integumentary specializations) is presented. Also, wing venation for these groups is reinterpreted, and new homology hypotheses for wing venation are proposed based on tracheation and comparative analyses. Given the high morphological divergence on the genital sclerites within the Mantispoidea, plus the confusing previous usage of neutral terminology and terms referring to appendages across taxonomic and morphological studies, we attempt to standardize, simplify, and situate terminology in an evolutionary context under the “gonocoxite concept” (multi-coxopod hypothesis). The remarkable morphological similarity of the genital sclerites of Symphrasinae and Rhachiberothidae (sensu U. Aspöck & Mansell 1994) with the Nallachinae (Dilaridae) was taken as a starting point to understand the morphology of other Mantispidae subfamilies. Based on these morphological comparisons, we provide a revised phylogenetic analysis of Mantispoidea. This new phylogenetic analysis supports a sister group relationship between the family Rhachiberothidae, comprising Rhachiberothinae and Symphrasinae, and the family Mantispidae, including the subfamily Mantispinae and its sister taxa Drepanicinae and Calomantispinae, which may represent a single subfamily. Based on these analyses, raptorial condition probably evolved a single time in these insects and subsequently became diversified in the two sister clades of the raptorial Mantispoidea.  

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