46 research outputs found
Proteomic analysis reveals the diversity and complexity of membrane proteins in chickpea (Cicer arietinum L.)
Background
Compartmentalization is a unique feature of eukaryotes that helps in maintaining cellular homeostasis not only in intra- and inter-organellar context, but also between the cells and the external environment. Plant cells are highly compartmentalized with a complex metabolic network governing various cellular events. The membranes are the most important constituents in such compartmentalization, and membrane-associated proteins play diverse roles in many cellular processes besides being part of integral component of many signaling cascades.
Results
To obtain valuable insight into the dynamic repertoire of membrane proteins, we have developed a proteome reference map of a grain legume, chickpea, using two-dimensional gel electrophoresis. MALDI-TOF/TOF and LC-ESI-MS/MS analysis led to the identification of 91 proteins involved in a variety of cellular functions viz., bioenergy, stress-responsive and signal transduction, metabolism, protein synthesis and degradation, among others. Significantly, 70% of the identified proteins are putative integral membrane proteins, possessing transmembrane domains.
Conclusions
The proteomic analysis revealed many resident integral membrane proteins as well as membrane-associated proteins including those not reported earlier. To our knowledge, this is the first report of membrane proteome from aerial tissues of a crop plant. The findings may provide a better understanding of the biochemical machinery of the plant membranes at the molecular level that might help in functional genomics studies of different developmental pathways and stress-responses
EhMAPK, the Mitogen-Activated Protein Kinase from Entamoeba histolytica Is Associated with Cell Survival
Mitogen Activated Protein Kinases (MAPKs) are a class of serine/threonine kinases that regulate a number of different cellular activities including cell proliferation, differentiation, survival and even death. The pathogen Entamoeba histolytica possess a single homologue of a typical MAPK gene (EhMAPK) whose identification was previously reported by us but its functional implications remained unexplored. EhMAPK, the only mitogen-activated protein kinase from the parasitic protist Entamoeba histolytica with Threonine-X-Tyrosine (TXY) phosphorylation motif was cloned, expressed in E. coli and functionally characterized under different stress conditions. The expression profile of EhMAPK at the protein and mRNA level remained similar among untreated, heat shocked and hydrogen peroxide-treated samples in all cases of dose and time. But a significant difference was obtained in the phosphorylation status of the protein in response to different stresses. Heat shock at 43°C or 0.5 mM H2O2 treatment enhanced the phosphorylation status of EhMAPK and augmented the kinase activity of the protein whereas 2.0 mM H2O2 treatment induced dephosphorylation of EhMAPK and loss of kinase activity. 2.0 mM H2O2 treatment reduced parasite viability significantly but heat shock and 0.5 mM H2O2 treatment failed to adversely affect E. histolytica viability. Therefore, a distinct possibility that activation of EhMAPK is associated with stress survival in E. histolytica is seen. Our study also gives a glimpse of the regulatory mechanism of the protein under in vivo conditions. Since the parasite genome lacks any typical homologue of mammalian MEK, the dual specificity kinases which are the upstream activators of MAPK, indications of the existence of some alternate regulatory mechanisms of the EhMAPK activity is perceived. These may include the autophosphorylation activity of the protein itself in combination with some upstream phosphatases which are not yet identified
Overview of the Dark Energy Spectroscopic Instrument
The Dark Energy Spectroscopic Instrument (DESI) is under construction to
measure the expansion history of the Universe using the Baryon Acoustic
Oscillation technique. The spectra of 35 million galaxies and quasars over
14000 square degrees will be measured during the life of the experiment. A new
prime focus corrector for the KPNO Mayall telescope will deliver light to 5000
fiber optic positioners. The fibers in turn feed ten broad-band spectrographs.
We present an overview of the instrumentation, the main technical requirements
and challenges, and the current status of the project.Comment: 11 pages, 4 figure
DESI Observations of the Andromeda Galaxy: Revealing the Immigration History of our Nearest Neighbor
DESI Observations of the Andromeda Galaxy: Revealing the Immigration History of our Nearest Neighbor
We present DESI observations of the inner halo of M31, which reveal the
kinematics of a recent merger - a galactic immigration event - in exquisite
detail. Of the 11,416 sources studied in 3.75 hour of on-sky exposure time,
7,438 are M31 sources with well measured radial velocities. The observations
reveal intricate coherent kinematic structure in the positions and velocities
of individual stars: streams, wedges, and chevrons. While hints of coherent
structures have been previously detected in M31, this is the first time they
have been seen with such detail and clarity in a galaxy beyond the Milky Way.
We find clear kinematic evidence for shell structures in the Giant Stellar
Stream, the Northeast Shelf and Western Shelf regions. The kinematics are
remarkably similar to the predictions of dynamical models constructed to
explain the spatial morphology of the inner halo. The results are consistent
with the interpretation that much of the substructure in the inner halo of M31
is produced by a single galactic immigration event 1 - 2 Gyr ago. Significant
numbers of metal-rich stars ([Fe/H]) are present in all of the detected
substructures, suggesting that the immigrating galaxy had an extended star
formation history. We also investigate the ability of the shells and Giant
Stellar Stream to constrain the gravitational potential of M31, and estimate
the mass within a projected radius of 125 kpc to be . The results herald a
new era in our ability to study stars on a galactic scale and the immigration
histories of galaxies.Comment: 45 pages, 22 figures, 8 tables; Astrophysical Journal in press; Data
at https://zenodo.org/record/697749
Overview of the instrumentation for the Dark Energy Spectroscopic Instrument
The Dark Energy Spectroscopic Instrument (DESI) embarked on an ambitious 5 yr survey in 2021 May to explore the nature of dark energy with spectroscopic measurements of 40 million galaxies and quasars. DESI will determine precise redshifts and employ the baryon acoustic oscillation method to measure distances from the nearby universe to beyond redshift z > 3.5, and employ redshift space distortions to measure the growth of structure and probe potential modifications to general relativity. We describe the significant instrumentation we developed to conduct the DESI survey. This includes: a wide-field, 3.°2 diameter prime-focus corrector; a focal plane system with 5020 fiber positioners on the 0.812 m diameter, aspheric focal surface; 10 continuous, high-efficiency fiber cable bundles that connect the focal plane to the spectrographs; and 10 identical spectrographs. Each spectrograph employs a pair of dichroics to split the light into three channels that together record the light from 360–980 nm with a spectral resolution that ranges from 2000–5000. We describe the science requirements, their connection to the technical requirements, the management of the project, and interfaces between subsystems. DESI was installed at the 4 m Mayall Telescope at Kitt Peak National Observatory and has achieved all of its performance goals. Some performance highlights include an rms positioner accuracy of better than 0.″1 and a median signal-to-noise ratio of 7 of the [O ii] doublet at 8 × 10−17 erg s−1 cm−2 in 1000 s for galaxies at z = 1.4–1.6. We conclude with additional highlights from the on-sky validation and commissioning, key successes, and lessons learned
Glycyrrhizin ameliorates insulin resistance, hyperglycemia, dyslipidemia and oxidative stress in fructose-induced metabolic syndrome-X in rat model
129-138<span style="font-size:11.0pt;font-family:
" times="" new="" roman";mso-fareast-font-family:"times="" roman";mso-bidi-font-family:="" mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:="" hi"="" lang="EN-GB">This study investigates if glycyrrhizin,<span style="mso-bidi-font-weight:
bold"> a constituent of licorice (Glycyrrhiza
glabra) root, is able to treat the complications (insulin
resistance, hyperglycemia, dyslipidemia and oxidative stress) of metabolic
syndrome. Metabolic syndrome was induced in rats by feeding a fructose-enriched
(60%) diet for six weeks, after which single dose of glycyrrhizin (50 mg/kg
body weight) was administered intraperitoneally. Different biochemical
parameters from blood were estimated during three weeks after treatment. Then
the rats were sacrificed to collect skeletal muscle tissue. Glycyrrhizin
reduced the enhanced levels of blood glucose, insulin and lipids in metabolic
syndrome group. Increased advanced glycation end products of hemoglobin,
glycohemoglobin, hemoglobin-mediated iron release and iron-mediated free
radical reactions (arachidonic acid and deoxyribose degradation) in metabolic
syndrome were inhibited by glycyrrhizin treatment. Reduced activities of
enzymatic antioxidants (superoxide dismutase and catalase) and elevated
oxidative stress markers (malonaldehyde, fructosamine, hemoglobin carbonyl
content and DNA damage) in metabolic syndrome were reversed to almost normal
levels by glycyrrhizin. The decreased levels of peroxisome proliferator
activated receptor (PPAR) and glucose transporter 4 (GLUT4) proteins in
skeletal muscle of metabolic syndrome group were elevated by glycyrrhizin,
indicating improved fatty acid oxidation and glucose homeostasis. </span