374 research outputs found
Curcumin-Loaded Mixed Micelles: Preparation, Characterization, and In Vitro
The objective of this study was to prepare curcumin-loaded mixed Soluplus/TPGS micelles (Cur-TPGS-PMs) for oral administration. The Cur-TPGS-PMs showed a mean size of 65.54 ± 2.57 nm, drug encapsulation efficiency over 85%, and drug loading of 8.17%. The Cur-TPGS-PMs were found to be stable in various pH media (pH 1.2 for 2 h, pH 6.8 for 2 h, and pH 7.4 for 6 h). The X-ray diffraction (XRD) patterns illustrated that curcumin was in the amorphous or molecular state within PMs. The In vitro release test indicated that Cur-TPGS-PMs possessed a significant sustained-release property. The cell viability in MCF-7 cells was found to be relatively lower in Cur-TPGS-PM-treated cells as compared to free Cur-treated cells. CLSM imaging revealed that mixed micelles were efficiently absorbed into the cytoplasm region of MCF-7 cells. Therefore, Cur-TPGS-PMs could have the significant value for the chronic breast cancer therapy
Characterization of a cryptic plasmid pSM429 and its application for heterologous expression in psychrophilic Pseudoalteromonas
<p>Abstract</p> <p>Background</p> <p><it>Pseudoalteromonas </it>is an important genus widespread in marine environment, and a lot of psychrophilic <it>Pseudoalteromonas </it>strains thrive in deep sea and polar sea. By now, there are only a few genetic systems for <it>Pseudoalteromonas </it>reported and no commercial <it>Pseudoalteromonas </it>genetic system is available, which impedes the study of <it>Pseudoalteromonas</it>, especially for psychrophilic strains. The aim of this study is to develop a heterologous expression system for psychrophilic <it>Pseudoalteromonas</it>.</p> <p>Results</p> <p>A cryptic plasmid pSM429 isolated from psychrophilic <it>Pseudoalteromonas </it>sp. BSi20429 from the Arctic sea ice, was sequenced and characterized. The plasmid pSM429 is 3874 bp in length, with a G+C content of 28%. Four putative open reading frames (ORFs) were identified on pSM429. Based on homology, the ORF4 was predicted to encode a replication initiation (Rep) protein. A shuttle vector (<it>Escherichia coli, Pseudoalteromonas</it>), pWD, was constructed by ligating pSM429 and pUC19 and inserting a chloramphenicol acetyl transferase (CAT) cassette conferring chloramphenicol resistance. To determine the minimal replicon of pSM429 and to check the functionality of identified ORFs, various pWD derivatives were constructed. All derivatives except the two smallest ones were shown to allow replication in <it>Pseudoalteromonas </it>sp. SM20429, a plasmid-cured strain of <it>Pseudoalteromonas </it>sp. BSi20429, suggesting that the <it>orf4 </it>and its flanking intergenic regions are essential for plasmid replication. Although not essential, the sequence including some repeats between <it>orf1 </it>and <it>orf2 </it>plays important roles in segregational stability of the plasmid. With the aid of pWD-derived plasmid pWD2, the erythromycin resistance gene and the <it>cd </it>gene encoding the catalytic domain of a cold-adapted cellulase were successfully expressed in <it>Pseudoalteromonas </it>sp. SM20429.</p> <p>Conclusions</p> <p>Plasmid pSM429 was isolated and characterized, and the regions essential for plasmid replication and stability were determined, helping the development of pSM429-based shuttle vectors. The shuttle vectors pWD and its derivatives could be used as cloning vectors for <it>Pseudoalteromonas</it>, offering new perspectives in the genetic manipulation of <it>Pseudoalteromonas </it>strains. With the aid of pWD-derived vector and its host, the erythromycin resistance gene and the <it>cd </it>gene of a cold-adapted protein were successfully expressed, indicating that the potential use of this system for recombinant protein production, especially for cold-adapted proteins.</p
Extracellular Matrix Peptides of Artemia Cyst Shell Participate in Protecting Encysted Embryos from Extreme Environments
BACKGROUND: Many species of the brine shrimp Artemia are found in various severe environments in many parts of the world where extreme salinity, high UV radiation levels, high pH, anoxia, large temperature fluctuations, and intermittent dry conditions are often recorded. To withstand adverse environments, Artemia undergoes an oviparous developmental pathway to release cysts whereas, under favorable conditions, swimming nauplius larvae are formed directly via an ovoviviparous pathway. In the former case these cysts have an extraordinary ability to keep the embryos protected from the harsh environment for long periods. This is achieved through the protection by a complex out-wrapping cyst shell. However, the formation and function of the cyst shell is complex; the details remain largely unclear. PRINCIPAL FINDING: A shell gland-specific gene (SGEG2) was cloned and identified from a suppression subtractive hybridization library. Western blot analysis showed that SGEG2 presumably requires post-translational proteolysis in order to be processed into two mature peptides (SGEG2a and 2b). The three matrix peptides (SGEG1 reported previously, 2a, and 2b) were found to distribute throughout the cyst shell. The results of gene knockdown by RNAi and subsequent resistance to environmental stresses assays indicated that these matrix peptides are required for cyst shell formation and are involved in protecting the encysted embryos from environmental stress. CONCLUSIONS/SIGNIFICANCE: This study revealed that extracellular matrix peptides participate in protecting embryos from extreme salinity, UV radiation, large temperature fluctuations and dry environments, thereby facilitating their survival. The cyst shell provides an excellent opportunity to link the ecological setting of an organism to the underlying physiological and biochemical processes enabling its survival. The cyst shell material has also a high potential to become an excellent new biomaterial with a high number of prospective uses due, specifically, to such biological characteristics
Orbital-angular-momentum dependent speckles for spatial mode sorting and multiplexed data transmission
Characterizing the orbital angular momentum (OAM) of a vortex beam is
critically important for OAM-encoded data transfer. However, in typical
OAM-based applications where vortex beams transmit through diffusers, the
accompanying scattering effect tends to be either deliberately prevented, or
characterized and then modulated actively based on complex wavefront shaping
and interferometry techniques. Here, we aim to investigate the characteristics
of blurred speckles obtained after a vortex beam transmits through a ground
glass diffuser. It is theoretically and experimentally demonstrated that a
cross-correlation annulus can be identified by implementing the
cross-correlation operation between speckle patterns corresponding to vortex
beams with different OAM values. Besides, it is worth noting that, the size of
the cross-correlation annulus is determined by the absolute value of the
topological charge difference between the two corresponding vortex beams. Based
on this mechanism, the OAM modes can be easily sorted from the incoherently
measured OAM-dependent speckles as well as their cross-correlation.
Furthermore, to make full use of the orthogonal feature of the OAM-dependent
speckles, demultiplexing of OAM-encoded data transfer is verified using a
ground glass diffuser. Both 8-bit grayscale and 24-bit RGB OAM-encoded data
transfers are carried out in experiments with superior error rates. We can
conclude that the OAM-dependent speckles can be not only utilized as a
competitive candidate for the OAM mode sorting function in a simple way but
also provide an efficient method for the demultiplexing of OAM-encoded data
transfer in a practical application
Higher Serum Uric Acid Is Associated with Higher Bone Mineral Density in Chinese Men with Type 2 Diabetes Mellitus
Accumulating evidence suggests that oxidative stress is associated with osteoporosis. Serum uric acid (UA) is a strong endogenous antioxidant. Therefore, we investigated the relationship between the serum UA and BMD in Chinese men with T2DM. In this cross-sectional study of 621 men with T2DM, BMDs at lumbar spine (L2–4), femoral neck (FN), and total hip (TH) were measured by dual-energy X-ray absorptiometry (DXA). Serum levels of UA, calcium (Ca), 25-OH vitamin D3 (vitD3), parathyroid hormone (PTH), and creatinine (Cr) were also tested. Data analyses revealed that serum UA levels were positively associated with BMD at all sites (p<0.05) in men with T2DM after adjusting for multiple confounders. The serum UA levels were positively correlated with body weight (r=0.322), body mass index (BMI) (r=0.331), Ca (r=0.179), and Cr (r=0.239) (p<0.001) and were also positively associated with the concentrations of PTH (r=0.10, p<0.05). When compared with those in the lowest tertile of UA levels, men with T2DM in the highest tertile had a lower prevalence of osteoporosis or osteopenia (adjusted odds ratio 0.54, 95% confidence interval [CI] 0.31–0.95). These data suggest that higher serum levels of UA are associated with higher BMDs and lower risks of osteoporosis in Chinese men with T2DM
Structure of cryptophyte photosystem II-light-harvesting antennae supercomplex.
Cryptophytes are ancestral photosynthetic organisms evolved from red algae through secondary endosymbiosis. They have developed alloxanthin-chlorophyll a/c2-binding proteins (ACPs) as light-harvesting complexes (LHCs). The distinctive properties of cryptophytes contribute to efficient oxygenic photosynthesis and underscore the evolutionary relationships of red-lineage plastids. Here we present the cryo-electron microscopy structure of the Photosystem II (PSII)-ACPII supercomplex from the cryptophyte Chroomonas placoidea. The structure includes a PSII dimer and twelve ACPII monomers forming four linear trimers. These trimers structurally resemble red algae LHCs and cryptophyte ACPI trimers that associate with Photosystem I (PSI), suggesting their close evolutionary links. We also determine a Chl a-binding subunit, Psb-γ, essential for stabilizing PSII-ACPII association. Furthermore, computational calculation provides insights into the excitation energy transfer pathways. Our study lays a solid structural foundation for understanding the light-energy capture and transfer in cryptophyte PSII-ACPII, evolutionary variations in PSII-LHCII, and the origin of red-lineage LHCIIs
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