472 research outputs found
The expression of 16KDa γ-zein in Arabidopsis induces proliferation of ER membranes and the formation of unconventional structures
No full textProlamins represent the major seed storage proteins in cereals and are peculiar of these plants, unlike the 7/11S globulins and 2S albumins present in all plants (1). Many prolamins form large insoluble polymers, termed protein bodies (PB), within the ER lumen, where they accumulate (2). In particular, maize prolamins (zeins) are grouped into four classes (α, β, γ, δ) being γ and β evolutively the most ancient and synthesized before α and δ during seed development (3). Three genes encode γ-zein polypeptides, of 16, 27 and 50 kD. The 27 kD γ-zein forms ER-located PB also when expressed in vegetative tissues of transgenic plants, indicating that it contains all the required information to form a PB (4). Its C-terminal region has high homology to 2S albumins, with four conserved intra-chain disulfide bonds, while the N-terminal region contains an amphypathic repeated domain and seven Cys residues (4, 5, 6). The insolubility of 27 kD γ-zein is related to the number of Cys residues in the first domain, that form inter-chain disulfide bonds; substitution of all these Cys with Ser residues leads to full solubility and secretion (7). The role of other structural determinants, such as the repeated domain is however less clear. 16 kD γ-zein almost completely lacks the amphypathic repeats has only four Cys in the N-terminal domain. It may lack also one of the intra-chain disulfide bonds in the C-terminal domain.
Arabidopsis plants constitutively expressing the 27 or the 16 kD polypeptides were produced. Biochemical analysis of leaves showed that 16 kD γ-zein forms polymers that remain in the ER but, unlike the 27 kD polypeptide, is does not form the insoluble PBs with high efficiency.
Comparative ultrastructural observations by TEM showed substantial differences in the ability of the two prolamins to form PBs. As expected, the 27 KDa γ-zein was able to form canonical, round shaped, compact PBs in the ER. Similar structures were rarely seen in leaves expressing 16 kD γ-zein, which instead formed layers of different thickness leaning ER membranes, as also confirmed by immunolabeling experiments. Intriguingly, these membranes abnormally proliferated to form large membranous bodies of different size up to 10-20 μm long in mesophyll cells. Occasionally, in the center of these membranous systems compact structures were present, however very irregular in shape. No other apparent ultrastructural changes were observed in the transformed plants in comparison with wt Arabidopsis.
The above results indicate that 16 KDa γ-zein is competent to polymerize, hence be retained in the ER. However, its polymerization mostly occurs in layers leaning ER membranes, which are somehow induced to proliferate to sustain this unusual process.
1. Shewry et al (1995) Plant Cell 7: 945-956; 2. Herman (2008) Curr Opin Plant Biol 11:672–679
3. Xu and Messing (2009) Theor Appl Genet 119:1397–1412; 4. Geli et al (1994) Plant Cell 6: 1911-1922; 5. Vitale et al (1982) Jof Exp Bot 33: 439-448; 6. Mainieri et al (2004) Plant Physiol 136:3447-3456: 7. Mainieri et al (2014) Front Plant Sci 5:33
A new asphalt binder parameter to predict asphalt concrete fatigue behavior
No full textSubmission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2022-12-01The student, Javier Garcia Mainieri, accepted the attached license on 2020-12-09 at 18:41.The student, Javier Garcia Mainieri, submitted this Thesis for approval on 2020-12-09 at 19:07.This Thesis was approved for publication on 2020-12-10 at 16:55.DSpace SAF Submission Ingestion Package generated from Vireo submission #16111 on 2021-03-04 at 16:33:54Made available in DSpace on 2021-03-05T21:47:36Z (GMT). No. of bitstreams: 2
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Previous issue date: 2020-12-10Embargo set by: Seth Robbins for item 117348
Lift date: 2023-03-05T21:47:41Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemAuthor requested closed access (OA after 2yrs) in Vireo ETD systemLimite
Two-face(s): ionized and neutral gas winds in the local Universe
No full textWe present a comprehensive study of the Na I λ5890, 5895 (Na I D) resonant lines in the Sloan Digital Sky Survey (SDSS, DR7) spectroscopic sample to look for neutral gas outflows in the local galaxies. Individual galaxy spectra are stacked in bins of stellar mass (M⋆) and star formation rate (SFR) to investigate the dependence of galactic wind occurrence and velocity as a function of the galaxy position in the SFR-M⋆ plane. While in most cases the interstellar medium (ISM) absorption and emission lines are at the galaxy systemic velocity, in massive galaxies (M⋆ > 5 × M☉) at the high SFR tail (SFR > 10-12 M☉ yr-1) we find evidence of a significant blue-shifted Na I D absorption, which we interpret as evidence of neutral outflowing gas. The occurrence of the blue-shifted absorption in the stacked spectra does not depend on the contribution of the nuclear activity as it is observed at the same significance for purely star-forming (SF) galaxies, active galactic nuclei (AGN), and composite systems at fixed SFR. We confirm, instead, for all classes of objects a clear dependence on the galaxy disc inclination: the blueshift is the largest and the Na I D equivalent width the smallest for face-on galaxies, while the absorption feature is at the systemic velocity for edge-on systems. This indicates that the neutral outflow is mostly perpendicular or biconical with respect to the galactic disc. We also compare the kinematics of the neutral gas with the ionized gas phase as traced by the [OIII]λ5007, Hα, [NII]λ6548, and [NII]λ6584 emission lines in the same galaxy spectra. Differently for the neutral gas phase, all the emission lines show evidence of perturbed kinematics only in galaxies with a significant level of nuclear activity, and they are independent of the galactic disc inclination. This would suggest that, while neutral winds originate from the galactic disc and are powered by SF feedback, ionized outflows are instead due to AGN feedback originating from the black hole accretion disc. In both the neutral and ionized gas phases, the observed wind velocities (of the order of 100-200 kms-1) suggest that the outflowing gas remains bound to the galaxy with no definitive effect on the gas reservoir
"The Borgia collection of Egyptian antiquities: cataloguing as a method"
No full textThe Borgia collection of Egyptian antiquities is one of the two main groups that constitute the Egyptian Collection of the National Archaeological Museum of Naples (MANN). The collection, sold by Camillo Borgia to Joachim Murat in 1815, however, is mainly linked to Cardinal Stefano Borgia (Camillo ‘s uncle) and the Danish scholar Georg Zoëga, who studied and catalogued it.
The scientific accuracy of Zoëga, motivated by the idea that we must present monuments for themselves and for their own contents and not according to individual taste and personal purposes, led him to develop a cataloguing system that made him a pioneer of a highly modern method for studying archaeological materials.
As part of a PhD project on the Egyptian collection of MANN, among whose main objectives is also a new exhibition proposal, consultation of archival documents - and especially of the original writings by Zoëga - is providing fundamental information about the nature and origin of some materials, as well as about their history in the context of European collectors in the late 18th and 19th centuries
Current Research in Egyptology 2017. Proceedings of the Conference held in Naples, 3rd-6th May 2016
No full textEffetti non genomici della 3,5,3’-L-Triiodotironina: induzione delle vie di segnalazione mediate da AMPK/ACC e AKT/PKB nel muscolo gastrocnemio di ratto
No full textDifferential expression of chitin synthase III and IV mRNAs in ascomata of Tuber borchii Vittad
No full textA Fusion between Domains of the Human Bone Morphogenetic Protein-2 and Maize 27 kD γ-Zein Accumulates to High Levels in the Endoplasmic Reticulum without Forming Protein Bodies in Transgenic Tobacco
No full textHuman Bone Morphogenetic Protein-2 (hBMP2) is an osteoinductive agent physiologically involved in bone remodeling processes. A commercialized recombinant hBMP2 produced in mammalian cell lines is available in different clinical applications where bone regeneration is needed, but widespread use has been hindered due to an unfavorable cost/effective ratio. Protein bodies are very large insoluble protein polymers that originate within the endoplasmic reticulum by prolamine accumulation during the cereal seed development. The N-terminal domain of the maize prolamin 27 kD γ-zein is able to promote protein body biogenesis when fused to other proteins. To produce high yield of recombinant hBMP2 active domain (ad) in stably transformed tobacco plants we have fused it to the γ-zein domain. We show that this zein-hBMP2ad fusion is retained in the endoplasmic reticulum without forming insoluble protein bodies. The accumulation levels are above 1% of total soluble leaf proteins, indicating that it could be a rapid and suitable strategy to produce hBMP2ad at affordable costs
SKELETAL MUSCLE MITOCHONDRIAL OXIDATIVE CAPACITY AND UNCOUPLING PROTEIN 3 ARE DIFFERENTLY INFLUENCED BY SEMISTARVATION AND REFEEDING
No full textSKELETAL MUSCLE MITOCHONDRIAL EFFICIENCY AND UNCOUPLING PROTEIN 3 IN OVEREATING RATS WITH INCREASED THERMOGENESIS
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