155 research outputs found
Olfactory proteins mediating chemical communication in the navel orangeworm moth, Amyelois transitella.
BackgroundThe navel orangeworm, Amyelois transitella Walker (Lepidoptera: Pyralidae), is the most serious insect pest of almonds and pistachios in California for which environmentally friendly alternative methods of control--like pheromone-based approaches--are highly desirable. Some constituents of the sex pheromone are unstable and could be replaced with parapheromones, which may be designed on the basis of molecular interaction of pheromones and pheromone-detecting olfactory proteins.MethodologyBy analyzing extracts from olfactory and non-olfactory tissues, we identified putative olfactory proteins, obtained their N-terminal amino acid sequences by Edman degradation, and used degenerate primers to clone the corresponding cDNAs by SMART RACE. Additionally, we used degenerate primers based on conserved sequences of known proteins to fish out other candidate olfactory genes. We expressed the gene encoding a newly identified pheromone-binding protein, which was analyzed by circular dichroism, fluorescence, and nuclear magnetic resonance, and used in a binding assay to assess affinity to pheromone components.ConclusionWe have cloned nine cDNAs encoding olfactory proteins from the navel orangeworm, including two pheromone-binding proteins, two general odorant-binding proteins, one chemosensory protein, one glutathione S-transferase, one antennal binding protein X, one sensory neuron membrane protein, and one odorant receptor. Of these, AtraPBP1 is highly enriched in male antennae. Fluorescence, CD and NMR studies suggest a dramatic pH-dependent conformational change, with high affinity to pheromone constituents at neutral pH and no binding at low pH
Local star-forming galaxies build up central mass concentration most actively near
To understand in what mass regime star-forming galaxies (SFGs) build up
central mass concentration most actively, we present a study on the
luminosity-weighted stellar age radial gradient ()
distribution of low-redshift SFGs using the MaNGA Pipe3D data
available in the SDSS DR17. The mean age gradient is negative, with
log Gyr/, consistent with the inside-out
disk formation scenario. Specifically, SFGs with positive
consist of at log, while this fraction rises
up to its peak () near log and then decreases
to at log. At fixed , SFGs with
positive typically have more compact sizes and more
centrally concentrated star formation than their counterparts, indicative of
recent central mass build-up events. These results suggest that the build-up of
central stellar mass concentration in local SFGs is mostly active near
. Our findings provide new insights on the origin of
morphological differences between low-mass and high-mass SFGs.Comment: 10 pages, 8 figures, accepted by Ap
Deep Imaging of the HCG 95 Field.I.Ultra-diffuse Galaxies
We present a detection of 89 candidates of ultra-diffuse galaxies (UDGs) in a
4.9 degree field centered on the Hickson Compact Group 95 (HCG 95) using
deep - and -band images taken with the Chinese Near Object Survey
Telescope. This field contains one rich galaxy cluster (Abell 2588 at
=0.199) and two poor clusters (Pegasus I at =0.013 and Pegasus II at
=0.040). The 89 candidates are likely associated with the two poor clusters,
giving about 50 60 true UDGs with a half-light radius kpc
and a central surface brightness mag arcsec. Deep
'-band images are available for 84 of the 89 galaxies from the Dark Energy
Camera Legacy Survey (DECaLS), confirming that these galaxies have an extremely
low central surface brightness. Moreover, our UDG candidates are spread over a
wide range in color, and 26% are as blue as normal star-forming
galaxies, which is suggestive of young UDGs that are still in formation.
Interestingly, we find that one UDG linked with HCG 95 is a gas-rich galaxy
with H I mass detected by the Very Large Array,
and has a stellar mass of . This
indicates that UDGs at least partially overlap with the population of nearly
dark galaxies found in deep H I surveys. Our results show that the high
abundance of blue UDGs in the HCG 95 field is favored by the environment of
poor galaxy clusters residing in H I-rich large-scale structures.Comment: Published in Ap
Spectroscopic Confirmation of two Extremely Massive Protoclusters BOSS1244 and BOSS1542 at
We present spectroscopic confirmation of two new massive galaxy protoclusters
at , BOSS1244 and BOSS1542, traced by groups of Coherently
Strong Ly Absorption (CoSLA) systems imprinted in the absorption
spectra of a number of quasars from the SDSS III and identified as
overdensities of narrowband-selected H emitters (HAEs). Using MMT/MMIRS
and LBT/LUCI near-infrared (NIR) spectroscopy, we confirm 46 and 36 HAEs in the
BOSS1244 and BOSS1542 fields, respectively. BOSS1244 displays a South-West (SW)
component at and another North-East (NE) component at
with the line-of-sight velocity dispersions of km
s and km s, respectively. Interestingly, we find that
the SW region of BOSS1244 contains two substructures in redshift space, likely
merging to form a larger system. In contrast, BOSS1542 exhibits an extended
filamentary structure with a low velocity dispersion of km s
at , providing a direct confirmation of a large-scale cosmic
web in the early Universe. The galaxy overdensities on the
scale of 15 cMpc are , , and for the
BOSS1244 SW, BOSS1244 NE, and BOSS1542 filament, respectively. They are the
most overdense galaxy protoclusters () discovered to date at
. These systems are expected to become virialized at with a total
mass of , and , respectively. Together with
BOSS1441 described in Cai et al. (2017a), these extremely massive overdensities
at exhibit different morphologies, indicating that they are in
different assembly stages in the formation of early galaxy clusters.Comment: 28 pages, 13 figures, 6 tables, accepted for publication in ApJ. The
complete Abstract is presented in the manuscrip
The Pressure Relief and Permeability Increase Mechanism of Crossing-Layers Directional Hydraulic Fracturing and Its Application
AbstractIn order to reduce roof-floor blind area of hydrofracture in underground mines, expand influenced range of fracturing, improve the effect of hydrofracture, a pressure relief and permeability increase model of hydraulic fracturing was built on the basis of analysing the mechanism of crack initiation and the characteristics of fracture development. After discussing the mechanism of directional hydraulic fracturing and carrying out related numerical simulation, a directional hydraulic fracturing technique was proposed. The coal fracture development distribution rule in the process of directional hydraulic fracturing was analysed, and the directional hydraulic fracturing technique was applied in the F15-31010 mining workface of The Twelfth Coal of Pingdingshan Coal Mining Group. The results show that single-drill hole fracturing effective radius rise to 6m under the pressure of 27Mpa, which is 3-5 times more than before, and the average concentration of single-drill hole gas drainage promote to 87.5%, average flow up 55.6% than no-directional hydraulic fracturing. All these suggest that the technology obtains remarkable effect, and has a high application value
Cold-adaptive alkaline protease from the psychrophilic Planomicrobium sp. 547: enzyme characterization and gene cloning
A psychrophilic bacterium strain 547 producing cold-adaptive alkaline protease was isolated from the deep sea sediment of Prydz Bay, Antarctica. The organism was identified as a Planomicrobium species by 16S rRNA analysis. The optimal and highest growth temperatures for strain 547 were 15℃ and 30℃, respectively. The extracellular protease was purified by ammonium sulfate precipitation and DEAE cellulose-52 chromatography. The optimal temperature and pH for the activity of the purified enzyme were 35℃ and pH 9.0, respectively. The enzyme retained approximately 40% of its activity after 2 h of incubation at 50℃. The enzymatic activity was inhibited by 1 mmol/L phenylmethyl sulfonylfluoride (PMSF) and hydrochloride 4-(2-aminoethyl)-benzenesulfonyl fluoride (AEBSF), indicating that it was a serine protease. The presence of Ca2+ and Mn2+ increased the activity of the enzyme. The protease gene with a size of 1 269 bp was cloned from Planomicrobium sp. 547 using primers designed based on the conserved sequences of proteases in GenBank. The Planomicrobium sp. 547 protease contained a domain belonging to the peptidase S8 family, which has a length of 309 amino acid (AA) residues. The alignment and phylogenetic analysis of the AA sequence indicated that the protease belonged to the subtilisin family
Enhanced inflammatory responses to toll-like receptor 2/4 stimulation in type 1 diabetic coronary artery endothelial cells: the effect of insulin
<p>Abstract</p> <p>Background</p> <p>Endothelial inflammatory responses mediated by Toll-like receptors (TLRs), particularly TLR2 and TLR4, play an important role in atherogenesis. While Type 1 diabetes (T1D) promotes the development and progression of atherosclerosis, the effect of T1D on TLR2/4-mediated inflammatory responses in coronary artery endothelial cells (CAECs) remains unclear.</p> <p>Methods</p> <p>We tested the hypothesis that diabetic CAECs have enhanced inflammatory responses to TLR2/4 stimulation. Non-diabetic and diabetic CAECs were treated with TLR2 agonist peptidoglycan and TLR4 agonist lipopolysaccharide. The expression of ICAM-1, IL-6 and IL-8 were analyzed by real-time PCR, immunoblotting and ELISA, and NF-κB activation by immunoblotting and immunostaining. In additional experiments, insulin was added before TLR stimulation to determine whether insulin deficiency alone is responsible for the alteration of TLR2/4-mediated inflammatory responses.</p> <p>Results</p> <p>Stimulation of TLR2 or TLR4 induced NF-κB activation, and the expression of ICAM-1, IL-6 and IL-8. Interestingly, the expression of inflammatory mediators was significantly enhanced in diabetic cells. The enhanced inflammatory responses correlated with augmented NF-κB activation in the absence of a change in TLR2 or TLR4 protein levels. Further, pretreatment of diabetic cells with insulin failed to suppress the enhanced inflammatory responses.</p> <p>Conclusions</p> <p>Diabetic CAECs have enhanced inflammatory responses to stimulation of TLR2 or TLR4, and insulin alone is insufficient to correct the hyper-inflammatory responses. The mechanism underlying the enhanced inflammatory responses appears to be augmentation of pro-inflammatory signaling, rather than up-regulation of levels of TLR2 and TLR4. These findings suggest that diabetic CAECs adopt a hyper-inflammatory phenotype and that this endothelial phenotypic change may predispose coronary artery to atherogenesis.</p
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