Ultrastructural studies on the oil bodies of Marchantia paleacea Bert. I. Early stages of oil-body cell differentiation: origination of the oil body

1978 ◽  
Vol 56 (18) ◽  
pp. 2252-2267 ◽  
Author(s):  
B. Galatis ◽  
P. Apostolakos ◽  
Chr. Katsaros

The differentiation of the idioblastic oil-body cells (OBC's) of Marchantia paleacea begins with the formation of protoplasmic and organelle complement in some thallus cells, which are meristematic in appearance. An increase of cytoplasm quantity and density, a proliferation of rough endoplasmic reticulum (ER) membranes, free ribosomes, dictyosomes, plastids, and mitochondria, as well as the appearance of cytoplasmic microtubules and the establishment of ER–plastid relationships were observed especially. These associations, together with the increased cytoplasm quantity, constitute accurate criteria for the identification of very young OBC's.The above protoplasmic changes are accompanied by the cell polarization; the nucleus is displaced at the one end of the cell and the vacuoles at the other end or peripherally. At these stages, the dictyosomes appear active and produce numerous smooth and coated vesicles.Gradually, at a more or less central area free of vacuoles, a number of ER membranes, dictyosomes, and dictyosome vesicles are preferentially localized. Microtubules fan out from this area toward the cell walls. The oil body (OB) appears in the form of a rudimentary 'vacuole,' at the centre of this area. Its bounding membrane is identical with the one of dictyosome vesicles and quite different from the ones of ER and typical vacuoles. Microtubules are associated with its contour, while rough ER membranes may surround it partly. The nascent OB grows further by the fusion of dictyosome vesicles, a phenomenon demonstrated for the coated vesicles and suggested for the smooth ones. The microtubules form a dense framework around the growing OB, while some of them are detected bridged with its limiting membrane. Actually, these microtubules appear to radiate out from the OB and persist until the first stages of lipophilic material elaboration.From the presented observations it is suggested that the OB's originate by the fusion of dictyosome vesicles through a mechanism in which microtubules play a key role. The ER membranes also seem to participate in the development of the newborn OB.

1978 ◽  
Vol 56 (18) ◽  
pp. 2268-2285 ◽  
Author(s):  
B. Galatis ◽  
Chr. Katsaros ◽  
P. Apostolakos

At the onset of the active synthesis of oil-body (OB) lipophilic material, the oil-body cells (OBC's) appear to have gained a high degree of specialization towards a specific type of secretory cell. They possess a dense ribosomal cytoplasm, an active Golgi apparatus, abundant rough endoplasmic reticulum (ER) membranes, ER-ensheathed chloroplasts, a peculiar compartment encompassed by a membrane resembling the plasmalemma, small vacuoles, and OB-associated microtubules as well as some subplasmalemmal ones. At these stages intimate associations between ER membranes and OB's are established, while another class of cytoplasmic tubules, some of which are associated with microbodies, is formed in the cytoplasm.Initially, some material (matrix) starts being accumulated in the OB compartment as well as on the inner face of its limiting membrane, where it forms a distinct layer. This accumulation is followed by the appearance of minute opaque lipophilic globules. The number and the size of the globules increase considerably, their structure is gradually differentiated, and matrix fills the globule-free space in scale and epidermal OB's. Each of them is not surrounded by a true membrane but is delimited by a thin layer of dense material. Some of the epidermal and a few scale OB's of the young thalli follow a diverse differentiation process and form one or a few large globules surrounded by a very thin layer of matrix. Ultimately, these OB's are destroyed and force the OBC's to break down. The mature inner OB's generally contain small globules, the membrane-associated material, and traces of matrix. A structural diversity exists between the OB's of young and mature thalli. In the latter all the OB's exhibit small globules only.The globules are exclusively elaborated in the OB which is an active cell element; cytoplasmic or plastidic lipophilic material has never been observed entering the OB. After the completion of their development, the OB's occupy most of the cell space; the protoplasm diminishes while the dictyosome and ER activity gradually ceases.The OB's are well preserved with osmium tetroxide fixation or with the double one with glutaraldehyde, performed at 0 °C, 4 °C, or at room temperature for 20 min, followed by osmium tetroxide. On the contrary, a prolonged glutaraldehyde prefixation at room temperature causes a destruction of the OB containing large globules, a partial degradation of the ones containing smaller globules, and removes the matrix almost totally.


2004 ◽  
Vol 279 (44) ◽  
pp. 45540-45545 ◽  
Author(s):  
Peter J. Eastmond

Castor bean endosperm contains a well known acid lipase activity that is associated with the oil body membrane. In order to identify this enzyme, proteomic analysis was performed on purified oil bodies. A ∼60-kDa protein was identified (RcOBL1), which shares homology with a lipase from the filamentous fungusRhizomucor miehei. RcOBL1 contains features that are characteristic of an α/β-hydrolase, such as a putative catalytic triad (SDH) and a conserved pentapeptide (GXSXG) surrounding the nucleophilic serine residue. RcOBL1 was expressed heterologously inEscherichia coliand shown to hydrolyze triolein at an acid pH (optima ∼4.5). RcOBL1 can hydrolyze a range of triacylglycerols but is not active on phospholipids. The activity is sensitive to the serine reagent diethylp-nitrophenyl phosphate, indicating that RcOBL1 is a serine esterase. Antibodies raised against RcOBL1 were used to show that the protein is restricted to the endosperm where it is associated with the surface of oil bodies. This is the first evidence for the molecular identity of an oil body-associated lipase from plants. Sequence comparisons reveal that families of OBL1-like proteins are present in many species, and it is likely that they play an important role in regulating lipolysis.


1958 ◽  
Vol 38 (3-4) ◽  
pp. 174-196 ◽  
Author(s):  
Paul Ashbee

The ruined and gutted barrow called Tregulland Burrow, when totally excavated, proved to have had a complex structure. Stake holes denoting withdrawn stakes, an infilled ‘ritual’ pit, a satellite grave containing a cremation and arrowheads, and most probably the central grave pit, were the features of the first phase of its construction. A cairn-ring, with a buttressing bank, the soil for which was dug from an encircling ditch, and its turf covering, comprised the second. A great slab bearing cup-marks and an ‘eyebrow’ motif, also other lesser cup-marked and ornamented slabs, were incorporated in cairn-ring and bank. Cup-marked stones recovered from the disturbed central area suggested the one-time existence of a stone-built grave incorporating such elements. After this second phase the barrow centre was open and arena-like, and a food vessel and a cremation were put in close by the cairn-ring. All was finally enveloped by material from the depths of the ditch. Poorly built walling or turves retained the final mound.


2021 ◽  
Vol 10 (20) ◽  
pp. 4668
Author(s):  
Luciano Quaranta ◽  
Carlo Bruttini ◽  
Giovanni De Angelis ◽  
Silvia Montescani ◽  
Alberto Ardizzone ◽  
...  

Purpose: To compare the number of hyper-reflective retinal spots (HRS) in optical coherence tomography (OCT) images of healthy controls and patients affected with primary open angle glaucoma (POAG). Methods: Thirty patients affected with POAG and 34 healthy controls were recruited and underwent raster OCT examination of the macular region. Among the acquired B-scans, the one with the lowest foveal thickness was selected, and a central area of 3000 μm was defined (region of interest, ROI), in order to identify HRS. HRS were defined as small point-like hyper-reflective elements, detectable at the visual inspection of the OCT image. HRS were independently counted by two investigators in the ROI of each OCT scan. Results: Inter-rater agreement for HRS counting was good to excellent (ICC = 0.96, 95% CI: 0.83–0.99). More HRS were found in the OCT images from glaucoma patients, in comparison with healthy controls (average value: 90.5 ± 13.02 and 74.72 ± 11.35, for glaucoma and healthy subjects, respectively; p < 0.01). Significant correlations between the average number of HRS and visual field mean deviation (MD, p = 0.01) and pattern standard deviation (PSD, p < 0.01) were found. Conclusions: OCT images from glaucoma patients showed a higher number of HRS when compared with healthy controls. As HRS have been hypothesized to be a sign of neuroinflammation, these results may support the role of neuroinflammation in glaucoma etiopathogenesis.


2019 ◽  
Vol 54 (1) ◽  
pp. 27-50
Author(s):  
Sarbani Sharma

While much has been said about the historicity of the Kashmir conflict or about how individuals and communities have resisted occupation and demanded the right to self-determination, much less has been said about nature of everyday life under these conditions. This article offers a glimpse of life in the working-class neighbourhood of Maisuma, located in the central area of the city of Srinagar, and its engagement with the political movement for azadi (freedom). I argue that the predicament of ‘double interminability’ characterises life in Maisuma—the interminable violence by the state on the one hand and simultaneously the constant call of labouring for azadi by the movement on the other, since the terms of peace are unacceptable.


2016 ◽  
Vol 13 (123) ◽  
pp. 20160677 ◽  
Author(s):  
Gustav Waschatko ◽  
Nils Billecke ◽  
Sascha Schwendy ◽  
Henriette Jaurich ◽  
Mischa Bonn ◽  
...  

Plant oleosomes are uniquely emulsified lipid reservoirs that serve as the primary energy source during seed germination. These oil bodies undergo significant changes regarding their size, composition and structure during normal seedling development; however, a detailed characterization of these oil body dynamics, which critically affect oil body extractability and nutritional value, has remained challenging because of a limited ability to monitor oil body location and composition during germination in situ . Here, we demonstrate via in situ , label-free imaging that oil bodies are highly dynamic intracellular organelles that are morphologically and biochemically remodelled extensively during germination. Label-free, coherent Raman microscopy (CRM) combined with bulk biochemical measurements revealed the temporal and spatial regulation of oil bodies in native soya bean cotyledons during the first eight days of germination. Oil bodies undergo a cycle of growth and shrinkage that is paralleled by lipid and protein compositional changes. Specifically, the total protein concentration associated with oil bodies increases in the first phase of germination and subsequently decreases. Lipids contained within the oil bodies change in saturation and chain length during germination. Our results show that CRM is a well-suited platform to monitor in situ lipid dynamics and local chemistry and that oil bodies are actively remodelled during germination. This underscores the dynamic role of lipid reservoirs in plant development.


1996 ◽  
Vol 314 (1) ◽  
pp. 333-337 ◽  
Author(s):  
Mark MILLICHIP ◽  
Arthur S. TATHAM ◽  
Frances JACKSON ◽  
Gareth GRIFFITHS ◽  
Peter R. SHEWRY ◽  
...  

Oil-bodies, from the immature cotyledons of sunflower (Helianthus annuus L.), were difficult to purify to homogeneity using conventional techniques. The major protein contaminants were albumin and globulin storage proteins. A protocol has been developed, therefore, based upon the stringent washing of the oil-body fraction in 9 M urea, which effectively removed almost all the contaminating protein as judged by SDS/PAGE. The urea-washed oil-bodies were enriched in two major proteins of Mr 19000 and 20000. These proteins were oleosins as demonstrated by their amino acid compositions and the sequence analysis of peptides produced by CNBr cleavage. Far-UV CD spectra of the oleosins in trifluoroethanol, trifluoroethanol/water mixtures and as mixed micelles in SDS, were typical of α-helical proteins with α-helical contents of some 55%. The phospholipid content of the urea-washed preparations was less than 0.1% of that required to form a half-unit membrane surrounding the oil-body. The oil-body surface therefore appears to be an unusual and novel structure, covered largely by an oleosin protein coat or pellicle rather than a conventional fluid membrane, half-unit or otherwise.


Author(s):  
David Sedley

Stoicism is the Greek philosophical system founded by Zeno of Citium c.300 bc and developed by him and his successors into the most influential philosophy of the Hellenistic age. It views the world as permeated by rationality and divinely planned as the best possible organization of matter. Moral goodness and happiness are achieved, if at all, by replicating that perfect rationality in oneself, and by finding out and enacting one’s own assigned role in the cosmic scheme of things. The leading figures in classical, or early, Stoicism are the school’s first three heads: Zeno of Citium, Cleanthes and Chrysippus. It is above all the brilliant and indefatigable Chrysippus who can be credited with building Stoicism up into a truly comprehensive system. ‘Early Stoicism’ - the main topic of this entry - is in effect largely identical with his philosophy. No formal philosophical writings of the early Stoics survives intact. We are mainly dependent on isolated quotations and secondary reports, many of them hostile. Nevertheless, the system has been reconstructed in great detail, and, despite gaps and uncertainties, it does live up to its own self-description as a unified whole. It is divided into three main parts: physics, logic and ethics. The world is an ideally good organism, whose own rational soul governs it for the best. Any impression of imperfection arises from misleadingly viewing its parts (including ourselves) in isolation, as if one were to consider the interests of the foot in isolation from the needs of the whole body. The entire sequence of cosmic events is pre-ordained in every detail. Being the best possible sequence, it is repeated identically from one world phase to the next, with each phase ending in a conflagration followed by cosmic renewal. The causal nexus of ‘fate’ does not, however, pre-empt our individual responsibility for our actions. These remain ‘in our power’, because we, rather than external circumstances, are their principal causes, and in some appropriate sense it is ‘possible’ for us to do otherwise, even though it is predetermined that we will not. At the lowest level of physical analysis, the world and its contents consist of two coextensive principles: passive ‘matter’ and active ‘god’. At the lowest observable level, however, these are already constituted into the four elements earth, water, air and fire. Air and fire form an active and pervasive life force called pneuma or ‘breath’, which constitutes the qualities of all bodies and, in an especially rarefied form, serves as the souls of living things. ‘Being’ is a property of bodies alone, but most things are analysed as bodies - even moral qualities, sounds, seasons and so forth - since only bodies can causally interact. For example, justice is the soul in a certain condition, the soul itself being pneuma and hence a body. A scheme of four ontological categories is used to aid this kind of analysis. In addition, four incorporeals are acknowledged: place, void, time and the lekton (roughly, the expressed content of a sentence or predicate). Universals are sidelined as fictional thought constructs, albeit rather useful ones. The world is a physical continuum, infinitely divisible and unpunctuated by any void, although surrounded by an infinite void. Its perfect rationality, and hence the existence of an immanent god, are defended by various versions of the Argument from Design, with apparent imperfections explained away, for example, as blessings in disguise or unavoidable concomitants of the best possible structure. ‘Logic’ includes not only dialectic, which is the science of argument and hence logic in its modern sense, but also theory of knowledge, as well as primarily linguistic disciplines like rhetoric and grammar. Stoic inferential logic takes as its basic units not individual terms, as in Aristotelian logic, but whole propositions. Simple propositions are classified into types, and organized into complex propositions (for example, conditionals) and complete arguments. All arguments conform to, or are reducible to, five basic ‘indemonstrable’ argument formats. The study of logical puzzles is another central area of Stoic research. The Stoics doggedly defended, against attacks from the sceptical Academy, the conviction that cognitive certainty is achieved through ordinary sensory encounters, provided an entirely clear impression (phantasia) is attained. This, the ‘cognitive impression’ (phantasia katalēptikē), is one of such a nature that the information it conveys could not be false. These self-certifying impressions, along with the natural ‘preconceptions’ (prolēpseis) which constitute human reason, are criteria of truth, on which fully scientific knowledge (epistēmē) - possessed only by the wise - can eventually be built. Stoic ethics starts from oikeiōsis, our natural ‘appropriation’ first of ourselves and later of those around us, which makes other-concern integral to human nature. Certain conventionally prized items, like honour and health, are commended by nature and should be sought, but not for their own sake. They are instrumentally preferable, because learning to choose rationally between them is a step towards the eventual goal of ‘living in agreement with nature’. It is the coherence of one’s choices, not the attainment of their objects, that matters. The patterns of action which promote such a life were systematically codified as kathēkonta, ‘proper functions’. Virtue and vice are intellectual states. Vice is founded on ‘passions’: these are at root false value judgments, in which we lose rational control by overvaluing things which are in fact indifferent. Virtue, a set of sciences governing moral choice, is the one thing of intrinsic worth and therefore genuinely ‘good’. The wise are not only the sole possessors of virtue and happiness, but also, paradoxically, of the things people conventionally value - beauty, freedom, power, and so on. However geographically scattered, the wise form a true community or ‘city’, governed by natural law. The school’s later phases are the ‘middle Stoicism’ of Panaetius and Posidonius (second to first century bc) and the ‘Roman’ period (first to second century ad) represented for us by the predominantly ethical writings of Seneca, Epictetus and Marcus Aurelius.


1983 ◽  
Vol 96 (4) ◽  
pp. 999-1007 ◽  
Author(s):  
R Bollini ◽  
A Vitale ◽  
MJ Chrispeels

Cotyledons of the common bean (Phaseolus vulgaris L.) synthesize large amounts of the reserve protein phaseolin. The polypeptides are synthesized on membrane-bound polysomes, pass through the endoplasmic reticulum (ER) and accumulate in protein bodies. For a study of the biosynthesis and processing of phaseolin, developing cotyledons were labeled with radioactive amino acids, glucosamine and mannose, and isolated fractions (polysomal RNA, polysomes, and rough ER) were used for in vitro protein synthesis. Newly synthesized phaseolin present in the ER of developing cotyledons can be fractioned into four glycopolypeptides by SDS PAGE. In vitro synthesis with polysomal RNA results in the formation of two polypeptides by polysome run-off shows that glycosylation is a co-translational event. The two unglycosylated polypeptides formed by polysome run-off are slightly smaller than the two polypeptides formed by in vitro translation of isolated RNA, indicating that a signal peptide may be present on these polypeptides. Run-off synthesis with rough ER produces a pattern of four polypeptides similar to the one obtained by in vivo labeling. The two abundant glycopolypeptides formed by polysome run-off. This result indicates the existence of a second glycosylation event for the abundant polypeptides. Inhibition of glycosylation by Triton X-100 during chain-completion with rough ER was used to show that these two glycosylation steps normally occur sequentially. Both glycosylation steps are inhibited by tunicamycin. Analysis of carhohydrate to protein ratios of the different polypeptides and of trypsin digests of polypeptides labeled with [(3)H]glucosamine confirmed the conclusion that some glycosylated polypeptides contain two oligosaccharide chains, while others contain only one. An analysis of tryptic peptide maps shows that each of the unglycosylated polypeptides is the precursor for one glycosylated polypeptide with one oligosaccharide chain and one with two oligosaccharide chains.


Genes ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 959
Author(s):  
Weidong Qiang ◽  
Tingting Gao ◽  
Xinxin Lan ◽  
Jinnan Guo ◽  
Muhammad Noman ◽  
...  

We set out to assess the NIH/3T3 cell proliferation activity of Arabidopsis oil body-expressed recombinant oleosin–hEGF–hEGF protein. Normally, human epidermal growth factor (hEGF) is purified through complex process, however, oleosin fusion technology provides an inexpensive and scalable platform for its purification. Under a phaseolin promoter, we concatenated oleosin gene to double hEGF (hEGF–hEGF) with plant-preferred codons in the expression vectors and the construct was transformed into Arabidopsis thaliana (Arabidopsis). The transgenic Arabidopsis was validated by RT–PCR and the content of recombinant protein oleosin–hEGF–hEGF was quantified by western blot. Subsequently, the proliferation assay and transdermal absorption were determined by MTT method and immunohistochemical staining, respectively. First, the expression level of hEGF was recorded to be 14.83-ng/μL oil body and due to smaller size transgenic oil bodies expressing the recombinant oleosin–hEGF–hEGF, they were more skin permeable than those of control. Second, via the staining intensity of transgenic oil bodies was greater than EGF at all time points via immunohistochemical staining in transdermal absorption process. Lastly, activity assays of oil bodies expressed oleosin–hEGF–hEGF indicated that they stimulated the NIH/3T3 cell proliferation activity. Our results revealed oil-body-expressed oleosin–hEGF–hEGF was potential new material having implications in the field of medicine.


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