scholarly journals Modeling lipid layers of atopic skin and observation of changes in lipid layer properties with changes in ceramide content

2020 ◽  
Author(s):  
In‐Keun Jung ◽  
Joonho Choi ◽  
Jin Nam ◽  
Kyoung Tai No
Keyword(s):  
Lipid Layer ◽  
Atopic Skin ◽  
Ceramide Content ◽  
Lipid Layers

The tylenchid (Nematoda) egg shell: formation of the egg shell in Meloidogyne javanica

Parasitology ◽  
1976 ◽  
Vol 72 (1) ◽  
pp. 29-39 ◽  
Author(s):  
Michael A. McClure ◽  
A. F. Bird
Keyword(s):  
Endoplasmic Reticulum ◽  
Meloidogyne Javanica ◽  
Distal Portion ◽  
Shell Formation ◽  
Lipid Layer ◽  
Dense Cytoplasm ◽  
Cytoplasmic Bridges ◽  
Pass Through ◽  
Egg Shell ◽  
Lipid Layers

SummaryOogonia of Meloidogyne javanica are radially arranged around a central rachis to which they are attached by cytoplasmic bridges. As the oocytes mature the rachis disappears and the oocytes pass through the oviduct in tandem. The oviduct-spermatotheca valve is constructed of two rows of tightly packed cells of which there are four per row. The nuclei of these cells are large and contain balloon-shaped cytoplasmic invaginations. The spermatotheca is characterized by microtubules which extend to its lumen and by invaginations of plasmalemma. Cells of the distal uterine region contain large intracytoplasmic spaces bordered by endoplasmic reticulum whereas proximal uterine cells have dense cytoplasm and large areas of compact endoplasmic reticulum. Egg-shell formation begins in the spermatotheca with the modification of the oolemma to form the vitelline layer. The chitinous layer begins in the distal portion of the uterus and appears to originate from the egg. Proline-containing protein is incorporated into the chitinous and lipid layers as the egg passes through the mid-region of the uterus and formation of the lipid layer in this region completes egg development.

The tylenchid (Nematoda) egg shell: structure, composition and permeability

Parasitology ◽  
1976 ◽  
Vol 72 (1) ◽  
pp. 19-28 ◽  
Author(s):  
Alan F. Bird ◽  
M. A. McClure
Keyword(s):  
Basic Structure ◽  
Vitelline Membrane ◽  
Chemical Components ◽  
Rotylenchulus Reniformis ◽  
Lipid Layer ◽  
Tylenchulus Semipenetrans ◽  
Different Temperatures ◽  
Egg Shells ◽  
Egg Shell ◽  
Lipid Layers

SummaryThe fine structure of egg shells of four different genera belonging to the order Tylenchida has been examined. The species examined were Meloidogyne javanica, Rotylenchulus reniformis, Tylenchulus semipenetrans and Pratylenchus minyus. They are all similar in their basic structure, being composed of vitelline membrane, chitin and lipid layers, but there is considerable variability in the thickness of these layers.We have retained the conventional nomenclature because of its convenience, but it is clear that these layers have a variety of chemical components. However, they do appear to contain the compounds from which they take their name. Thus chitin occurs in the chitin layer, and lipid in the lipid layer. The latter is removed by the technique used in isolating the shell from the egg. Chemical analysis of the hydrolysis products of these shells has revealed a high (35 %) proline content which appears to be a characteristic of those nematode egg shells which have been examined so far. These analyses and treatment with enzymes indicate that the chitin layer is a chitin–protein complex.Experiments on the permeability of eggs of M. javanica at different temperatures indicate that changes in permeability are not due to the melting of a single lipid with a distinct melting point as had been thought in the past. We have found that Arrhenius activation energies calculated from the two slopes of an Arrhenius plot were 17·8 kcal/mol and 43·0 kcal/mol respectively, the transition from one to the other taking place at 62°C. We think that these changes are due to changes in the properties of lipoprotein membranes in the lipid layer. These membranes appear to be of paramount importance in controlling the permeability of the nematode egg shell.

Oogenesis and egg-shell formation in Aspiculuris tetraptera Schulz (Nematoda: Oxyuroidea)

Parasitology ◽  
1979 ◽  
Vol 78 (2) ◽  
pp. 131-143 ◽  
Author(s):  
D. A. Wharton
Keyword(s):  
Vitelline Membrane ◽  
Shell Formation ◽  
Perivitelline Space ◽  
Lipid Layer ◽  
Cytoplasmic Inclusions ◽  
Inner Surface ◽  
Egg Shell ◽  
Aspiculuris Tetraptera ◽  
Lipid Layers

SUMMARYThe ovary of Aspiculuris tetraptera has a prominent terminal cap cell. This is considered to be part of the ovarian epithelium. Oogonia detach from the short rachis and increase in size from 6 to 60 μm; accumulating hyaline granules, shell granules and glycogen. The hyaline granules persist in the egg cytoplasm after shell formation has been completed and are considered to be lipoprotein yolk. The shell granules contribute to the non-chitin fraction of the chitinous layer. A classification of the cytoplasmic inclusions of the nematode oocyte is proposed. Upon fertilization a vitelline membrane is formed which constitutes the vitelline layer of the egg-shell. The chitinous layer is secreted in the perivitelline space, between the vitelline layer and the egg oolemma. Upon completion of chitinous layer synthesis, the egg cytoplasm contracts away from its inner surface. The material of the lipid layer is secreted at the surface of the egg cytoplasm and adheres to the inner surface of the chitinous layer. During secretion of the chitinous and lipid layers by the egg cytoplasm, the uterine cells secrete the unit membrane-like external uterine layer and the crystalline internal uterine layer. A complex system of interconnecting spaces develops in the internal uterine layer. This system is open to the exterior via breaks in the external uterine layer. There is no direct involvement of the uterine cells in the formation of this structure.

scholarly journals Characteristics of dry eye patients with thick tear film lipid layers evaluated by a LipiView II interferometer

2021 ◽  
Author(s):  
Yunjin Lee ◽  
Joon Young Hyon ◽  
Hyun Sun Jeon
Keyword(s):  
Dry Eye ◽  
Ocular Surface ◽  
Tear Film ◽  
Sensitivity Analyses ◽  
Lipid Layer ◽  
Ocular Surface Disease Index ◽  
Surface Staining ◽  
Physiologic Condition ◽  
Cautious Interpretation ◽  
Lipid Layers

Abstract Purpose To investigate the characteristics of eyes with dry eye disease (DED) whose lipid layer thickness (LLT) measured 100 nm on a LipiView II interferometer and compare the DED parameters of them to those with LLT below 100 nm. Methods A total of 201 eyes of 102 enrolled DED patients (mean age 56.4 ± 11.8 years) were classified into 3 groups according to their average LLT; < 60 nm as thin-LLT (n = 49), 60–99 nm as normal-LLT (n = 77), and 100 nm as thick-LLT (n = 75). LLT, meiboscore, Schirmer I test, tear film break-up time (TBUT), ocular surface staining (OSS), and ocular surface disease index (OSDI) were assessed. Results The OSS and TBUT were significantly worse in the thick-LLT group than in the normal-LLT group (p = 0.020, and p = 0.028, respectively). The OSDI was significantly higher in the thick-LLT group than in the thin-LLT group (p = 0.006). However, the meiboscore was not different among the three groups (p = 0.33). Age, OSS, and OSDI showed a positive correlation with LLT (r = 0.16, p = 0.023; r = 0.213, p = 0.003; and r = 0.338, p = 0.001, respectively). In sensitivity analyses, eyes with corneal erosions had a significantly higher average LLT (p = 0.015), higher OSDI (p = 0.009), shorter TBUT (p < 0.001), and shorter Schirmer I value (p = 0.024) than those with clear corneas. Conclusion The average LLT of eyes with corneal erosions was thicker than those without erosions, suggesting that the LLT of 100 nm in the eyes with corneal erosions should not be regarded as a stable physiologic condition. Cautious interpretation of LLT along with other dry eye parameters is required.

The tylenchid (Nematoda) egg shell: structure, composition and permeability

Parasitology ◽  
1976 ◽  
Vol 72 (1) ◽  
pp. 19-28 ◽  
Author(s):  
Alan F. Bird ◽  
M. A. McClure
Keyword(s):  
Basic Structure ◽  
Vitelline Membrane ◽  
Chemical Components ◽  
Rotylenchulus Reniformis ◽  
Lipid Layer ◽  
Tylenchulus Semipenetrans ◽  
Different Temperatures ◽  
Egg Shells ◽  
Egg Shell ◽  
Lipid Layers

The fine structure of egg shells of four different genera belonging to the order Tylenchida has been examined. The species examined were Meloido-gyne javanica, Rotylenchulus reniformis, Tylenchulus semipenetrans and Pratylenchus minyus. They are all similar in their basic structure, being composed of vitelline membrane, chitin and lipid layers, but there is considerable variability in the thickness of these layers.We have retained the conventional nomenclature because of its convenience, but it is clear that these layers have a variety of chemical components. However, they do appear to contain the compounds from which they take their name. Thus chitin occurs in the chitin layer, and lipid in the lipid layer. The latter is removed by the technique used in isolating the shell from the egg. Chemical analysis of the hydrolysis products of these shells has revealed a high (35 %) proline content which appears to be a characteristic of those nematode egg shells which have been examined so far. These analyses and treatment with enzymes indicate that the chitin layer is a chitin-protein complex.Experiments on the permeability of eggs of M. javanica at different temperatures indicate that changes in permeability are not due to the melting of a single lipid with a distinct melting point as had been thought in the past. We have found that Arrhenius activation energies calculated from the two slopes of an Arrhenius plot were 17·8 kcal/mol and 43·0 kcal/mol respectively, the transition from one to the other taking place at 62°C. We think that these changes are due to changes in the properties of lipoprotein membranes in the lipid layer. These membranes appear to be of paramount importance in controlling the permeability of the nematode egg shell.

The tylenchid (Nematoda) egg shell: formation of the egg shell in Meloidogyne javanica

Parasitology ◽  
1976 ◽  
Vol 72 (1) ◽  
pp. 29-39 ◽  
Author(s):  
Michael A. McClure ◽  
A. F. Bird
Keyword(s):  
Endoplasmic Reticulum ◽  
Meloidogyne Javanica ◽  
Distal Portion ◽  
Shell Formation ◽  
Lipid Layer ◽  
Dense Cytoplasm ◽  
Cytoplasmic Bridges ◽  
Pass Through ◽  
Egg Shell ◽  
Lipid Layers

Oogonia of Meloidogyne javanica are radially arranged around a central rachis to which they are attached by cytoplasmic bridges. As the oocytes mature the rachis disappears and the oocytes pass through the oviduct in tandem. The oviduct-spermatotheca valve is constructed of two rows of tightly packed cells of which there are four per row. The nuclei of these cells are large and contain balloon-shaped cytoplasmic invaginations. The spermatotheca is characterized by microtubules which extend to its lumen and by invaginations of plasmalemma. Cells of the distal uterine region contain large intracytoplasmic spaces bordered by endoplasmic reticulum whereas proximal uterine cells have dense cytoplasm and large areas of compact endoplasmic reticulum. Egg-shell formation begins in the spermatotheca with the modification of the oolemma to form the vitelline layer. The chitinous layer begins in the distal portion of the uterus and appears to originate from the egg. Proline-containing protein is incorporated into the chitinous and lipid layers as the egg passes through the mid-region of the uterus and formation of the lipid layer in this region completes egg development.

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