scholarly journals TheTrichoplaxmicrobiome: the simplest animal lives in an intimate symbiosis with two intracellular bacteria

2019 ◽  
Author(s):  
Harald R. Gruber-Vodicka ◽  
Nikolaus Leisch ◽  
Manuel Kleiner ◽  
Tjorven Hinzke ◽  
Manuel Liebeke ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Epithelial Cells ◽  
Rough Endoplasmic Reticulum ◽  
New Genus ◽  
Electron Tomography ◽  
Intracellular Bacteria ◽  
Correlative Microscopy ◽  
Fiber Cells ◽  
Single Host ◽  
Key Genes

Summary paragraphPlacozoa is an enigmatic phylum of simple, microscopic, marine metazoans. Although intracellular bacteria have been found in all members of this phylum, almost nothing is known about their identity, location and interactions with their host. We used metagenomic and metatranscriptomic sequencing of single host individuals, plus metaproteomic and imaging analyses, to show that the placozoanTrichoplaxH2 lives in symbiosis with two intracellular bacteria. One symbiont forms a new genus in the Midichloriaceae (Rickettsiales) and has a genomic repertoire similar to that of rickettsial parasites, but does not appear to express key genes for energy parasitism. Correlative microscopy and 3-D electron tomography revealed that this symbiont resides in an unusual location, the rough endoplasmic reticulum of its host’s internal fiber cells. The second symbiont belongs to the Margulisbacteria, a phylum without cultured representatives and not known to form intracellular associations. This symbiont lives in the ventral epithelial cells ofTrichoplax, likely metabolizes algal lipids digested by its host, and has the capacity to supplement the placozoan’s nutrition. Our study shows that even the simplest animals known have evolved highly specific and intimate associations with symbiotic, intracellular bacteria, and highlights that symbioses with microorganisms are a basal trait of animal life.

Ultrastructure of the Genital Duct Epithelium of the Male Port Jackson Shark, Heterodontus-Portusjacksoni

1992 ◽  
Vol 40 (3) ◽  
pp. 257 ◽  
Author(s):  
RC Jones ◽  
M Lin
Keyword(s):  
Endoplasmic Reticulum ◽  
Epithelial Cells ◽  
Golgi Apparatus ◽  
Rough Endoplasmic Reticulum ◽  
Secretory Granules ◽  
Close Association ◽  
Ciliated Cells ◽  
Dense Bodies ◽  
Ductuli Efferentes ◽  
Apical Vesicles

The genital ducts of Heterodontus portusjacksoni are lined by a ciliated epithelium. In the ductuli efferentes the epithelium is low and contains numerous intraepithelial leucocytes which often contain large dense bodies. All epithelial cells are ciliated and are characterised by apical vesicles, vacuoles and glycogen granules, some rough endoplasmic reticulum, dense bodies and lipid droplets, and a Golgi apparatus. The initial segment of the ductus epididymidis is lined by a very tall epithelium of ciliated and non-ciliated cells. The non-ciliated cells contain numerous apical vesicles, a large Golgi apparatus and numerous mitochondria and secretory granules in close association with an extensive endoplasmic reticulum. The terminal segment of the ductus epididymidis is lined by a low columnar epithelium. A proximal region, occupying part of the head of the epididymis, is similar to the epithelium in the ductuli efferentes. Distally, all the epithelial cells are ciliated. They are characterised by considerable dilated endoplasmic reticulum, a Golgi apparatus, apical vesicles, and numerous mitochondria and secretory granules. The secretory tubules of Leydig's glands are lined by a very tall epithelium with non-ciliated cells containing extensive, dilated, rough endoplasmic reticulum, a large Golgi apparatus, and numerous mitochondria and secretory granules. The significance of the structural differentiation of the duct is discussed in relation to the evolution of the mammalian epididymis.

Alpha(S1)-casein is required for the efficient transport of beta- and kappa-casein from the endoplasmic reticulum to the Golgi apparatus of mammary epithelial cells

1999 ◽  
Vol 112 (19) ◽  
pp. 3399-3412 ◽  
Author(s):  
E. Chanat ◽  
P. Martin ◽  
M. Ollivier-Bousquet
Keyword(s):  
Endoplasmic Reticulum ◽  
Epithelial Cells ◽  
Golgi Apparatus ◽  
Rough Endoplasmic Reticulum ◽  
Mammary Epithelial Cells ◽  
Whey Proteins ◽  
Mammary Epithelial ◽  
The Other ◽  
Soluble Form ◽  
Beta Casein

In lactating mammary epithelial cells, interaction between caseins is believed to occur after their transport out of the endoplasmic reticulum. We show here that, in alpha(S1)-casein-deficient goats, the rate of transport of the other caseins to the Golgi apparatus is highly reduced whereas secretion of whey proteins is not significantly affected. This leads to accumulation of immature caseins in distended rough endoplasmic reticulum cisternae. Casein micelles, nevertheless, were still observed in secretory vesicles. In contrast, no accumulation was found in mammary epithelial cells which lack beta-casein. In mammary epithelial cells secreting an intermediate amount of alpha(S1)-casein, less casein accumulated in the rough endoplasmic reticulum, and the transport of alpha(S1)-casein to the Golgi occurred with kinetics similar to that of control cells. In prolactin-treated mouse mammary epithelial HC11 cells, which do not express alpha(S)-caseins, endoplasmic reticulum accumulation of beta-casein was also observed. The amount of several endoplasmic reticulum-resident proteins increased in conjunction with casein accumulation. Finally, the permeabilization of rough endoplasmic reticulum vesicles allowed the recovery of the accumulated caseins in soluble form. We conclude that optimal export of the caseins out of the endoplasmic reticulum is dependent upon alpha(S1)-casein. Our data suggest that alpha(S1)-casein interacts with the other caseins in the rough endoplasmic reticulum and that the formation of this complex is required for their efficient export to the Golgi.

scholarly journals Progressive Depletion of Rough Endoplasmic Reticulum in Epithelial Cells of the Small Intestine in Monosodium Glutamate Mice Model of Obesity

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Kazuhiko Nakadate ◽  
Kento Motojima ◽  
Tomoya Hirakawa ◽  
Sawako Tanaka-Nakadate
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Small Intestine ◽  
Epithelial Cells ◽  
Rough Endoplasmic Reticulum ◽  
Defense Mechanism ◽  
Monosodium Glutamate ◽  
Light And Electron Microscopy ◽  
Obese Mice ◽  
Pathological Changes

Chronic obesity is a known risk factor for metabolic syndrome. However, little is known about pathological changes in the small intestine associated with chronic obesity. This study investigated cellular and subcellular level changes in the small intestine of obese mice. In this study, a mouse model of obesity was established by early postnatal administration of monosodium glutamate. Changes in body weight were monitored, and pathological changes in the small intestine were evaluated using hematoxylin-eosin and Nissl staining and light and electron microscopy. Consequently, obese mice were significantly heavier compared with controls from 9 weeks of age. Villi in the small intestine of obese mice were elongated and thinned. There was reduced hematoxylin staining in the epithelium of the small intestine of obese mice. Electron microscopy revealed a significant decrease in and shortening of rough endoplasmic reticulum in epithelial cells of the small intestine of obese mice compared with normal mice. The decrease in rough endoplasmic reticulum in the small intestine epithelial cells of obese mice indicates that obesity starting in childhood influences various functions of the small intestine, such as protein synthesis, and could impair both the defense mechanism against invasion of pathogenic microbes and nutritional absorption.

Alcoholic Hyalin and Cytoplasmic Filaments in Biliary Epithelial Cells

1972 ◽  
Vol 30 ◽  
pp. 260-261
Author(s):  
Odell T. Minick ◽  
Hidejiro Yokoo ◽  
Fawzia Batti
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Liver Disease ◽  
Epithelial Cells ◽  
Rough Endoplasmic Reticulum ◽  
Alcoholic Liver Disease ◽  
Biliary Epithelial Cells ◽  
Cytoplasmic Filaments ◽  
Alcoholic Hyalin ◽  
A Site

Biliary epithelial cells have previously been shown to be a site of alcoholic hyalin (AH) deposition. To learn more of the nature and pathogenesis of this inclusion, the fine structure of proliferating biliary ductules was studied in 20 patients with alcoholic liver disease. The changes were compared with those observed in hepatocytes containing alcoholic hyalin.The ductular cells often displayed dilated cisternae of rough endoplasmic reticulum, prominent Golgi complexes, and an increase in lysosomes. Mitochondria were larger, more numerous and contained more cristae than those usually seen in ductules (Fig. 1). Double nuclei were common. Dense, compact cells, probably degenerative in nature, were often noted.

scholarly journals The involvement of endogenous dolichol in the formation of lipid-linked precursors of glycoprotein in rat liver

1974 ◽  
Vol 138 (2) ◽  
pp. 281-289 ◽  
Author(s):  
H. G. Martin ◽  
Kareen J. I. Thorne
Keyword(s):  
Endoplasmic Reticulum ◽  
Epithelial Cells ◽  
Rat Liver ◽  
Rough Endoplasmic Reticulum ◽  
Intestinal Epithelial Cells ◽  
Subcellular Fractions ◽  
Intestinal Epithelial ◽  
Glycoprotein Synthesis ◽  
Chemical Cleavage ◽  
Rat Tissue

Endogenous dolichol was shown to function as a natural acceptor of mannose residues by using regenerating rat liver containing [3H]dolichol. When subcellular fractions from this liver were incubated with GDP-[14C]mannose a double-labelled lipid, which represented 30% of the total [14C]mannolipid, could be isolated. This lipid was shown to be identical with the dolichol phosphate mannose formed from exogenous dolichol phosphate, by chromatography, stability to alkali and by chemical cleavage to mannose and dolichol derivatives. It was formed by the rough endoplasmic reticulum and mitochondria. If it is concerned in glycoprotein synthesis this would suggest that it functions in the formation of both secreted and mitochondrial glycoproteins. When both the dolichol and retinol of rat tissue were radioactive they made similar contributions to the synthesis of the lipid by liver microsomal fractions and intestinal epithelial cells.

EFFECTS OF INTRADUCTAL PROLACTIN ON SOME ASPECTS OF THE ULTRA-STRUCTURE AND BIOCHEMISTRY OF MAMMARY TISSUE IN THE PSEUDOPREGNANT RABBIT

1971 ◽  
Vol 49 (3) ◽  
pp. 459-469 ◽  
Author(s):  
T. J. FIDDLER ◽  
MARGARET BIRKINSHAW ◽  
I. R. FALCONER
Keyword(s):  
Endoplasmic Reticulum ◽  
Epithelial Cells ◽  
Rough Endoplasmic Reticulum ◽  
Mammary Epithelial Cells ◽  
Smooth Endoplasmic Reticulum ◽  
Progressive Increase ◽  
Mammary Epithelial ◽  
Mammary Tissue ◽  
Hormone Administration ◽  
Large Numbers

SUMMARY A study of the ultrastructure of the secretory epithelial cells of the mammary gland was carried out in virgin oestrous rabbits, pseudopregnant rabbits and pseudopregnant rabbits injected with prolactin to induce lactogenesis. Ultrastructural modifications of the mammary epithelial cells, from inactivity to active secretion after an intraductal injection of prolactin, are described. The changes produced after prolactin injection were characterized by a progressive increase in endoplasmic reticulum and in ribosomes in the cytoplasm. This was evident after 12–24 h. By the 2nd or 3rd day after hormone administration the cells had differentiated into active secretory epithelium. These cells were characterized by large numbers of ribosomes in the cytoplasm; an extensive development of rough endoplasmic reticulum; development of cisternae from the enlarging rough endoplasmic reticulum; hypertrophy of the Golgi apparatus and smooth endoplasmic reticulum; and the presence of protein granules in the vacuoles which were particularly abundant in the cytoplasm near the duct lumen. The presence of lipid droplets in the cells was less indicative of an active secretory state since they were also observed in mammary tissue from pseudopregnant rabbits. Biochemical investigation of the response of pseudopregnant mammary tissue to intraductal prolactin showed no significant rapid effects on either casein-like protein or lactose biosynthesis, but increases in both substances were observed on the 3rd day after hormone administration.

Ultrastructural Changes Associated with Alcoholic Hyalin in Hepatocytes and Biliary Epithelial Cells

1971 ◽  
Vol 29 ◽  
pp. 572-573
Author(s):  
Odell T. Minick ◽  
Hidejiro Yokoo ◽  
Fawzia Batti
Keyword(s):  
Endoplasmic Reticulum ◽  
Epithelial Cells ◽  
Liver Biopsy ◽  
Alcoholic Hepatitis ◽  
Ultrastructural Changes ◽  
Main Mass ◽  
Biliary Epithelial Cells ◽  
Biopsy Specimens ◽  
Alcoholic Hyalin

To learn more of the nature and origin of alcoholic hyalin (AH), 15 liver biopsy specimens from patients with alcoholic hepatitis were studied in detail.AH was found not only in hepatocytes but also in ductular cells (Figs. 1 and 2), although in the latter location only rarely. The bulk of AH consisted of a randomly oriented network of closely packed filaments measuring about 150 Å in width. Bundles of filaments smaller in diameter (40-90 Å) were observed along the periphery of the main mass (Fig. 1), often surrounding it in a rim-like fashion. Fine filaments were also found close to the nucleus in both hepatocytes and biliary epithelial cells, the latter even though characteristic AH was not present (Figs. 3 and 4). Dispersed among the larger filaments were glycogen, RNA particles and profiles of endoplasmic reticulum. Dilated cisternae of endoplasmic reticulum were often conspicuous around the periphery of the AH mass. A limiting membrane was not observed.

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