Large Lipid Bodies Research Articles

Ultrastructure of interstitial cells of Cajal at the colonic submuscular border in patients with ulcerative colitis

BACKGROUND & AIMS: Submuscular interstitial cells of Cajal (ICC) are putative pacemaker cells of the colonic external muscle. Although motility disturbances and smooth muscle dysfunction are prevalent in patients with ulcerative colitis (UC), ICC have never been studied in this disease. The aim of this study was to examine the ultrastructure of submuscular ICC in UC. METHODS: Transmission electron microscopy of the colonic submuscular region was performed using specimens from 4 adult patients who had undergone resection for severe UC. The specimens were compared with similarly processed control samples. RESULTS: ICC often showed multiple secondary lysosomes, large confluent lipid bodies, and disrupted aggregates of vacuolated glycogen clusters. Intermediate filaments showed margination and clumping. Intramuscular and submucosal nerve terminals were often swollen. Macrophages were frequent, often close to nerves and ICC. Muscle cells of the innermost circular layer, fibroblast-like cells, and glial cells appeared undisturbed. Other inflammatory cells were inconspicuous. CONCLUSIONS: Alterations of ICC ultrastructure are present in the submuscular pacemaker region of the colon in patients with severe UC. The changes in ICC may result from primary damage or changes secondary to defective muscular function, or they may reflect neuroimmune-mediated metabolic responses. It is suggested that ICC are actively involved in the pathogenesis of motility disturbances in UC. (Gastroenterology 1996 Dec;111(6):1447-55)

Two new male‐sterile mutants ofZea mays (Poaceae) with abnormal tapetal cell morphology

Two new recessive male‐sterile mutants of Zea mays (Poaceae), or maize, were studied to identify the timing of pollen abortion and to examine the involvement of anther wall cell layers. The results of test crosses indicated that these mutants were not allelic with any known male‐sterile mutants of maize. Light and transmission electron microscopy were used to compare pollen development in homozygous male‐sterile mutants to that in fertile heterozygous siblings. In both mutants, microspores abort soon after release from the meiotic tetrad. However, the two mutations have strikingly different phenotypes. Large lipid bodies accumulate in the tapetal cells as the microspores vacuolate and die in the mutant ms25. Large vacuoles appear in both the tapetal cells and the young microspores as they begin to disintegrate in the mutant ms26. Because abnormal tapetal cell morphology is detected in both mutants, it is possible that both of these mutations affect the expression of genes in tapetal cells.

Human uterine mast cells. Isolation, purification, characterization, ultrastructure, and pharmacology.

As part of an ongoing investigation of human mast cell heterogeneity, we have isolated, partially purified, and characterized the uterine mast cell and compared it with mast cells isolated from other organs. The average histamine content of myometrium and leiomyofibroma obtained from hysterectomies was 2.1 +/- 0.3 (mean +/- SEM) microgram/g of tissue (n = 10), and the histamine content of the two tissues did not differ significantly. A mild collagenase, hyaluronidase, and DNase digestion was used to disperse the uterine mast cells, with an average yield of 9.5% (range, 0 to 21%). The average histamine/uterine mast cell was 2.1 +/- 0.2 pg (n = 3), and 61 +/- 7% (n= 3) of the uterine mast cells survived overnight culture. Early purification efforts with Percoll gradients have yielded up to 80% pure uterine mast cells, with an average of 27 +/- 10% (n = 5). Uterine mast cells released histamine in response to the secretogogues anti-IgE and A23187 but did not respond to substance P or to the basophil secretogogues FMLP, C5a, and 12-O-tetradecanoylphorbol-13-acetate. After 1 microgram/ml anti-IgE stimulation, the uterine mast cell appeared to make significant quantities of PGD2 (89 +/- 26 ng/10(6) cells, n = 6) (p less than 0.05), as assayed by RIA. Simultaneously, leukotriene C4 release was 45 +/- 15 ng/10(6) cells, (n = 6) (p less than 0.05), as assayed by RIA. Combined gas-chromatography mass spectroscopy analysis of anti-IgE-stimulated cell supernatants confirmed the production of PGD2. In pharmacologic studies, isobutyl-methylxanthine and isoproterenol blocked anti-IgE-induced histamine release. The uterine mast cell is similar to the lung mast cell in terms of response to secretogogues and release of arachidonic acid metabolites. Ultrastructurally, the uterine mast cell contains scroll granules, crystal granules, combined granules, homogeneously dense granules, and large lipid bodies, many with focal lucencies within them. Particle granules, most frequently present in gut mast cells of mucosal origin, were absent from uterine mast cells. Although certain features are analogous to the ultrastructure of skin or lung mast cells, the combination of structures is distinctive for uterine mast cells.

Seasonal changes in leaf lipids of Diapensia lapponica, with special reference to storage lipid bodies

Seasonal fluctuations in storage lipids in the cushion plant Diapensia lapponica, growing in Northern Finland (70°N 27°E), were studied by microscopy and chemical analysis. Lipid bodies in the mesophyll cells were stained with Sudan Black for quantitative observation by light microscope. Electron microscope observations were made using aldehyde prefixed and osmium tetroxide postfixed sections of leaf blades. Thin layer and gas capillary chromatographic techniques were used to analyse total lipids and total fatty acids in green shoots of Diapensia. Free sugars and starch were extracted separately and determined by the anthrone method.A mesophyll cell was characterized by a large lipid body (storage lipid) in summer but by several small spherules in winter. Total surface area of the cross‐sectioned lipid globules was at its lowest from April to September; the maximal value was in March. The amount of total lipids in the leafy tops of D. lapponica was 91–200 mg g‐1 dry weight. Values were lowest at the end of June, when the total carbohydrate level was at its highest. Accordingly, the decrease in the total lipid level in the early growing season, when new leaves were developing, can be attributed primarily to the increase in the level of carbohydrates, particularly starch. The amount of total fatty acids varied from 21 to 30 mg g‐1 dry weight. The level increased in the early growing season and remained elevated throughout the summer. Like the total lipids, the total fatty acids are derived from structurally different parts of the sclerophyllous leaves, including the well‐developed cuticle and epicuticular wax layer. The discrepancies in the results obtained from microscopic and chemical analyses are discussed.

Histochemical and ultrastructural changes in the haustorium of date (Phoenix dactylifera L.)

During imbibition ofPhoenix dactylifera embryos, all cotyledon cells show the same changes: protein and lipid bodies degrade, smooth endoplasmic reticulum (ER) increases in amount, and dictyosomes appear. At germination, the distal portion of the cotyledon expands to form the haustorium. At this time, epithelial cells have a dense cytoplasm with many extremely small vacuoles. Many ribosomes are present along with ER, dictyosomes, and mitochondria. The parenchyma cells have large vacuoles and a small amount of peripheral cytoplasm. Between 2 and 6 weeks after germination, epithelial cells still retain the dense cytoplasm and many organelles appear: glyoxysomes, large lipid bodies, amyloplasts, large osmiophilic bodies, and abundant rough and smooth ER which appear to merge into the plasmalemma. A thin electron-transparent inner wall layer with many small internal projections is added to the cell walls. Starch grains appear first in the subsurface and internal parenchyma and subsequently in the epithelium. Lipid bodies, glyoxysomes, protein, and osmiophilic bodies occur in the epithelial and subepithelial cell layers but not in the internal parenchyma. At 8 weeks after germination, the cytoplasm becomes electron transparent, vacuolation occurs, lipid bodies and osmiophilic bodies degrade, and the endomembranes disassemble. After 10 weeks, the cells are empty. These data support the hypothesis that the major functions of the haustorium are absorption and storage.

Ultrastructural Studies on the Microconidia of Botrytis cinerea Pers. and their Phialoconidial Development

AbstractThe genesis and ultrastructure of microconidia of Botrytis cinerea Pers. were studied, using TEM and SEM.Microconidia are produced in flask‐shaped, terminal or lateral phialides. The first microconidium develops holoblastically, subsequent microconidia are formed enteroblastically, in basipetal succession from a fixed conidiogenous locus.Mature microconidia are characterized by a two‐layered spore wall covered by mucilage, a single, sickle‐shaped nucleus, one or two large lipid bodies, a few mitochondria of the cristae‐type, ribosomes, sparse endoplasmatic reticulum close to the plasmalemma and a small amount of cytoplasma. The basal septum which is surrounded by a collar‐like rim is perforated by a simple central pore with a pore plug.Differences in genesis and ultrastructure of microconidia compared with macroconidia are discussed in relation to the function of these two spore types.

Production of Multiple Vacuoles as an Early Event in the Ontogeny of Protein Bodies in Developing Soybean Seeds1

We have made an ultrastructural study of developing soybean seeds, cultivar Wells [Glycine max. (L.) Merr.], using light and electron microscopy in an attempt to resolve the question of protein body ontogeny. Formation of numerous small vacuoles from the central vacuole was observed as early as 17 days after flowering (DAF). The process continued until each cell contained many small vacuoles. There was a close association between development of rough endoplasmic reticulum (RER) and Golgi bodies and the appearance of protein bodies. Proliferation of RER was observed by 34 DAF, and the vacuoles filled with reserve protein to form distinct protein bodies. Many small vesicles were derived from RER and Golgi bodies but these did not appear to develop into protein bodies. These vesicles may be concerned with transport of storage protein to multiple vacuolar sites for deposition of reserve protein into protein bodies. Protein bodies increased both in size and number as the seed developed. At later stages of seed development, around 60 DAF, RER disappeared and many large protein bodies and numerous lipid bodies were visible in cotyledon cells. The results of our study demonstrates the following: (i) early subdivision of the central vacuoles (17 DAF) appears to be the source of protein bodies; (ii) there is no apparent physical connection between the RER and protein bodies; (iii) accumulation of starch and lipid reserves in soybean seed clearly precedes that of storage protein; (iv) appearance of membrane‐bound polyribosomes (not free ribosomes) is consistent with the onset of storage protein; and (v) at physiological maturity, most cell organelles had disappeared.

A physiological study of Panicum maximum infected by Phyllachora paspalicola

Detailed morphological studies of the leaf pathogen Phyllachora paspalicola (tarspot) on its host Panicum maximum Jacq. have been previously described. This research reports physiological changes in leaf tissue infected by P. paspalicola. Aspects of photosynthetic and nitrogen metabolism were studied in healthy and tarspot-infected leaf tissue. Concentrations of glucose, fructose, and sucrose in infected and noninfected leaves were also measured. Gross and net photosynthetic rates declined significantly in tarspot-infected leaves at high disease intensities (>25%). Chlorophyll content declined in leaves exhibiting >25% infection. Transmission electron microscopy revealed disruption of lamellae and formation of large lipid bodies in infected mesophyll and bundle sheath cells. Significant changes in some C4 enzymes, such as NADP malate dehydrogenase, aspartate aminotransferase, ribulose-1,5-bisphosphate carboxylase, phosphoenolpyruvate carboxylase, were noted in tarspot-infected leaves. Small differences in the activities of NADP–malate enzyme and alanine aminotransferase were also observed. Activity of the respiratory enzyme succinate dehydrogenase was also stimulated in intensely infected leaves. An increase in nitrate levels was measured as ascopore sporogenesis occurred. At sporulation and during postsporulation, total nitrogen declined in leaves exhibiting intense infection (>25%). A small increase in glucose and fructose content occurred in leaves exhibiting mature fruiting bodies, whereas a significant (p = 0.05) increase in sucrose content was observed in infected leaves.

Melanosomes in Paget's Disease of the Human Nipple

Paget's disease of the nipple is a distinct pathologic entity associated with intraductal and/or invasive carcinoma of the breast. Paget's change in the nipple is observed in 2.5% of breast malignancies. It is associated with progressive clinical changes corresponding to progressive microscopic infiltration of the nipple epidermis by “Paget” cells. The underlying intraductal carcinoma typically involves the lacteriferous sinuses and is often multifocal. Theories regarding the histogenesis of Paget's disease include: 1) ductal carcinoma cells migrating into the nipple epidermis; 2) melanocytes; 3) squamous cells of the nipple; and 4) keratinocytes which differentiate into glandular malignant cells. The histologic characteristics of Paget's disease include nests of large pale cells with granular cytoplasm and hyperchromatic nuclei with prominent nucleoli, in the epidermis of the nipple. The tumors may show continuity with underlying carcinoma of the lacteriferous ducts. Paget cells are characterized ultrastructurally by an electron lucent cytoplasm with numerous polyribosomes, extensive rough endoplasmic reticulum and golgi, numerous large mitochondria, lysosome-like inclusions, lipid bodies, and glycogen particles.

Ultrastructure of carpospores inGastroclonium clavatum (Roth)Ardissone (Rhodymeniales)

Carpospores ofG. clavatum have been studied under the light and electron microscopes. They are wedge-shaped cells of 80–100 μm at their longest diameters. The nucleus is an uncondensed structure provided with a regular outline and a large nucleolus. The plastids constitute heterogeneous populations of organelles differing in size and shape as well as in number and arrangement of the thylakoids. Multiplicating plastids are also present. The mitochondria are small but have well developed cristae. The Golgi apparatus consists of very numerous active dictyosomes. Starch is the main storage substance but some large lipid bodies are also present. Labyrinthine polysaccharide aggregations are present in the carposporial cytoplasm. Multilayered bodies constitute a “sui generis” very conspicuous cell component.

Studies of the powdery-mildew fungus, Leveillula taurica, on green pepper. II. Light and electron microscopic observation of the infection process

Almost all ultrastructural studies of powdery-mildew fungi have been focused on the epiparasitic fungi. In this paper, one of the endoparasitic powdery-mildew fungi, Leveillula taurica (Lev.) Arn., on green pepper (Capsicum annuum L. var. angulosum Mill.) leaves was investigated by light and electron microscopy. Most germinated conidia formed a lobed adhesion body (similar to the appressorium in morphology but different in function) before stomatal invasion. The track of the adhesion body on the leaf epidermis was depressed, and no cuticular perforations were observed in it. After stomatal invasion, infection hyphae grew extensively into the intercellular spaces of the leaves and formed haustoria in the spongy- and palisade-parenchyma cells. The haustorium was flask shaped with a neck arising from the intercellular hypha. The overall profiles of the haustorium resembled those of epiphytic powdery-mildew fungi of other authors; the haustorium was composed of a nucleate central body and many anucleate lobes, and the entire structure was bounded by an extrahaustorial membrane. Papillae consisting of three distinct regions formed against the outer cell walls at the site of penetration. The most obvious alteration in infected host cells was a marked increase in the number of large lipid bodies. Lipid bodies increased in number with time after haustorial formation. They appeared first in the host cytoplasm near the extrahaustorial membrane, then in the extrahaustorial matrix and haustorial body.

Ultrastructure of the Egg Apparatus of Nicotiana tabacum (Solanaceae) Before and After Fertilization

The egg apparatus of Nicotiana tabacum was studied from just before flower opening until 92 h after pollination. Each synergid has a large nucleus and nucleolus and a prominent chalazal vacuole. Numerous mitochondria, plastids with starch, dictyosomes, free ribosomes, and rough endoplasmic reticulum (ER) are present. A cell wall exists only around the micropylar half of the synergids, and each cell has a distinct filiform apparatus. Numerous conspicuous cell-wall evaginations located just chalazal to the hook region extend laterally from the synergids into the central cell. The egg has a chalazally located nucleus with a single nucleolus and a large micropylar vacuole. With the exception of dictyosomes, the same cytoplasmic organelles are present in the egg as in the synergids, but in much lesser amounts. A continuous cell wall is not present around the chalazal end of the egg. Before pollination, numerous large lipid bodies are localized in the outer integumentary cells. Near the time of fertilization ma...

Ultrastructure of the vitelline follicles of Gorgoderina vitelliloba (Trematoda: Gorgoderidae)

An electron microscope study of the vitelline follicles of Gorgoderina vitelliloba indicates that they contain vitelline cells in various stages of development. Juvenile cells are small and characterised by a little cytoplasm. During differentiation a large amount of granular endoplasmic reticulum develops. In more mature cells, indistinct Golgi complexes give rise to globules of shell protein which migrate to form clusters at the periphery of the cell. Further maturation results in the appearance of large lipid bodies in the vitelline cell cytoplasm. Developing vitelline cells are ensheathed by nurse cell cytoplasm containing numerous small vacuoles which appear to be derived from smooth endoplasmic reticulum. It is suggested that nurse cells may have a role in selection and transport of nutrient material for vitelline cells and that they manufacture precursors of lipid which is subsequently stored as a food reserve in mature vitelline cells. Possible transport sites between parenchymal cells and nurse cells were identified.

Histopathological and ultrastructural comparison of Stemphylium sarcinaeforme and S. botryosum on red clover foliage

As part of a continuing study of non-host resistance, red clover leaves inoculated with the clover pathogen Stemphylium sarcinaeforme, or the closely related alfalfa pathogen S. botryosum, were examined by light and electron microscopy to compare the events occurring in the initial stages of infection. Stemphylium botryosum penetrated leaves primarily via the stomata with resultant death of the guard cells and with varying effects on adjacent epidermal cells. Appressoria were frequently formed, and although they rarely resulted in successful penetrations, the contacted epidermal cells were often markedly affected as judged by toluidine blue staining. Growth of hyphae was intercellular but very limited in its extent. At some infection sites, one to several mesophyll cells underwent extensive plasmolysis and cytoplasmic disruption. Less severely affected mesophyll cells contained large lipid bodies, abundant rough endoplasmic reticulum, and Golgi vesicles and had wall appositions at points of contact with necrotic cells or with hyphae. Stemphylium sarcinaeforme generally penetrated between or directly through the epidermal cells, causing death of the contacted cells. Hyphae grew intercellularly or intracellularly in the palisade tissue and hyphal elongation was considerably more rapid than that of S. botryosum. Palisade cells adjacent to, or containing, the hyphae underwent several different types of cytoplasmic deterioration. Mesophyll cells surrounding these areas showed the same features as comparable cells in tissue infected by S. botryosum. In tissue infected by either fungus, the exterior of host cell walls was coated with a layer of extracellular material.

The ultrastructure of the R.S. zoospore of the Chytridiomycete Physoderma gerhardti

The fine structure of the zoospore of Physoderma gerhardti Schroeter is described. It possesses a single very large lipid body (sometimes accompanied by several smaller ones) situated laterally to the nuclear cap – nucleus complex and is associated with electron-dense material (the microbody) and the single large posteriorly located mitochondrion. The single posterior flagellum proximally terminates in a kinetosome just short of the posterior cone-shaped end of the nucleus. The kinetosome lies in a deep groove in the mitochondrion and is associated with this organelle by striated rootlets. The kinetosome terminates in electron-dense material from which an array of microtubules arises. These microtubules run along the sides of the cone-shaped nucleus and nuclear cap. There is an accessory centriole lying close to and more or less parallel with the kinetosome. The cytoplasm contains a small amount of smooth endoplasmic reticulum and several inclusion bodies in the anterior region and several small vacuoles in the posterior region of the cell. The general internal organization of the zoospore of Physoderma gerhardti more nearly resembles that of a blastocladiaceous fungus than of any chytrid thus far investigated.

Fine structure of a symbiont-bearing colonial radiolarian, Collosphaera globularis, and 14C isotopic evidence for assimilation of organic substances from its zooxanthellae

Collosphaera globularis Haeckel is a colonial radiolarian consisting of numerous radiolarian cells and their dinoflagellate symbionts enclosed within the translucent wall of a hollow gelatinous spheroid. Each radiolarian cell is surrounded by a finely porous, siliceous shell which segregates the host cell body from the zooxanthellae in the peripheral ectoplasm. A large lipid body occurs in the center of each radiolarian cell and is surrounded by a layer of endoplasm containing numerous nuclei with cord-like strands of chromatin, tubular cristae mitochondria, and endoplasmic reticulum. The zooxanthellae are sequestered in large vacuoles within the rhizopodial network. Positive evidence for host assimilation of photosynthetically derived organic substances is presented and may partially explain the remarkable abundance of these organisms in oligotrophic regions of the ocean.

An ultrastructural and cytochemical study of microbodies in the genus Nitella (Characeae)

Electron microscopy of the cells of the characean alga Nitella flexilis revealed the presence of numerous spherical inclusions which morphologically resemble plant microbodies. The structures have a dense granular matrix and are bounded by a single membrane. Many of the microbodies contain very electron-dense nucleoids that were shown to be alpha-amylase sensitive. In cells of the young apex, microbodies are the most abundant cellular organelle and are intimately associated with dilated cisternae of the endoplasmic reticulum and Golgi complexes, and with large osmiophilic lipid bodies. Although the microbody population appears reduced in mature branchlet cells and internode cells of the main axis, they exhibit a characteristic and frequent association with the chloroplasts. Turnover of microbodies involves some autolytic degradation of the body matrix until complete digestion presumably occurs. Developmental changes of microbodies were monitored with the cytochemical localization of lysosomal aryl sulfatase and acid phosphatase activities. The current study is of interest since catalase, an enzyme marker of microbodies in a variety of tissues, could not be detected using both cytochemical and enzyme assay methods. The functional role of microbodies in Nitella cells is explored in relation to presently available information.

Biochemical and morphologic changes in rat submandibular gland in experimental protein-calorie malnutrition

Prolonged feeding of a low protein diet to young male rats aged about 5 weeks to reproduce the syndrome of protein-calorie malnutrition found in deprived children revealed prominent changes in the submandibular salivary gland. The atrophic edematous gland demonstrated marked involutionary alterations in the acinar cells as well as an arrest of the normal age dependent differentiation and developmental patterns usually observed in the parenchymal cells of the tubular components. Morphologic studies indicated fragmentation and dilatation of the endoplasmic reticulum as well as accumulation of large lipid bodies and the presence of cytoplasmic vacuoles and small, abnormal looking secretory granules. These morphologic indices of impairment in protein synthesis were associated with reduced organ contents of nucleic acids and protein, distorted amino acid pattern, and pronounced disaggregation of the polyribosomes. In view of the importance of the salivary glands and their secretions in the defense mechanisms of the oral tissues, detailed studies are strongly indicated to evaluate any possible role of salivary gland malfunction in the unusually high susceptibility of malnourished children to periodontal disease.

The ultrastructure of wheat leaves I. Changes due to natural senescence and the effects of kinetin and ABA on detached leaves incubated in the dark

Detached wheat leaves incubated in water in darkness rapidly lose starch and are ultrastructurally degenerate by 5 days. Chloroplast ribosomes disappear before cytoplasmic ribosomes and groups of wavy membranes can be detected in both mature and degenerating chloroplasts. Large lipid bodies appear in the cytoplasm and vacuole during senescence, and osmiophilic fibrils and deposits develop in the microbodies. Treatment with kinetin via the transpiration stream markedly delays the loss of starch and maintains, but does not increase, chloroplast and cytoplasmic ribosome populations. ABA accelerates degenerative changes as compared with the water treated control leaves but does not induce any specific ultrastructural effects.

Notes on the ultrastructure of the microconidium and stroma in Sclerotinia sclerotiorum.

An electron microscope study has been done on the structure of microconidia and stroma of Sclerotinia sclerotiorum. The microconidia showed the usual cell organelles already described for other species of this genus, e.g. a large nucleus and large lipid body, a few mitochondria and sparse endoplasmic reticulum. The stromatal ultrastructure presented hyphae with a rich content in lipid bodies and storage vacuoles as food reserve. Simple septa with plugged pores were occasionally seen. Although the existence of two kinds of hyphae, one with abundant food materials and the other type with a degenerated aspect, both hyphae showed a similar thickness in their cell walls approximately 0.2 μ, and the diameter of these hyphae was 1.5–3 μ.