A putative multidrug efflux gene,
, was cloned from the
K-12 strain. A drugsensitive strain of
missing the main multidrug efflux pump AcrB was constructed as a host and the yddA gene was knocked out ...in wild-type (WT) and drug-sensitive
Δ
to study the
function. Sensitivity to different substrates of WT
,
Δ
,
Δ
and
Δ
Δ
strains was compared with minimal inhibitory concentration (MIC) assays and fluorescence tests. MIC assay and fluorescence test results showed that YddA protein was a multidrug efflux pump that exported multiple substrates. Three inhibitors,
-vanadate, carbonyl cyanide m-chlorophenylhydrazone (CCCP), and reserpine, were used in fluorescence tests.
-vanadate and reserpine significantly inhibited the efflux and increased accumulation of ethidium bromide and norfloxacin, while CCCP had no significant effect on YddA-regulated efflux. The results indicated that YddA relies on energy released from ATP hydrolysis to transfer the substrates and YddA is an ABC-type multidrug exporter. Functional study of unknown ATP-binding cassette (ABC) superfamily transporters in the model organism
is conducive to discovering new multidrug resistance-reversal targets and providing references for studying other ABC proteins of unknown function.
Abstract
Background
Mesenchymal stem cells (MSCs) have become a promising candidate for cell-based immune therapy for acute rejection (AR) after heart transplantation due to possessing ...immunomodulatory properties. In this study, we evaluated the efficacy of soluble fibronectin-like protein 2 (sFgl2) overexpressing mesenchymal stem cells (sFgl2-MSCs) in inhibiting AR of heart transplantation in mice by regulating immune tolerance through inducing M2 phenotype macrophage polarization.
Methods and results
The sFgl2, a novel immunomodulatory factor secreted by regulatory T cells, was transfected into MSCs to enhance their immunosuppressive functions. After being co-cultured for 72 h, the sFgl2-MSCs inhibited M1 polarization whereas promoted M2 of polarization macrophages through STAT1 and NF-κB pathways in vitro. Besides, the sFgl2-MSCs significantly enhanced the migration and phagocytosis ability of macrophages stimulated with interferon-γ (IFN-γ) and lipopolysaccharide (LPS). Further, the application potential of sFgl2-MSCs in AR treatment was demonstrated by heterotopic cardiac transplantation in mice. The tissue damage and macrophage infiltration were evaluated by H&E and immunohistochemistry staining, and the secretion of inflammatory cytokines was analyzed by ELISA. The results showed that sFgl2-MSCs injected intravenously were able to locate in the graft, promote the M2 polarization of macrophages in vivo, regulate the local and systemic immune response, significantly protect tissues from damaging, and finally prolonged the survival time of mice heart grafts.
Conclusion
sFgl2-MSCs ameliorate AR of heart transplantation by regulating macrophages, which provides a new idea for the development of anti-AR treatment methods after heart transplantation.
The Caofeidian Reclamation Project has been the biggest reclamation project in China so far, in which 310km
2
sea areas were reclaimed along the coast of Hebei Province, and it also bring about many ...problems and defects for large reclaiming area. The study focuses on the influences of the engineering exerted on evolution of the Laolonggou Lagoon with the methods of topographical measurement and surface sediment analysis. The results demonstrate that the topographical changes in the Laolonggou Lagoon had been controlled obviously by the engineering at three stages. Besides, blocking and reopening of the shoal tidal channel also affected the geological environment of the lagoon area. In the aspect of topographical change, the Laolonggou Inlet first experienced deposition after the shoal tidal channel was blocked, followed by short-time eroding for quarrying and cofferdam construction in the east, then depositing slowly after the reclaiming activity ceased, and finally eroding after the shoal tidal channel was reopened. The project, particularly cofferdam construction led to the movement of the Laolonggou Inlet axis from west to east for 50–100m. In the aspect of sediment variation, the reclamation project and hydrodynamic change resulted in the variation in compositions and distribution pattern. The western lagoon area has become land mainly constituted by silt, while the sediments in the eastern area have turned finer in size. After the shoal tidal channel was reopened, the current velocity in the Laolonggou Inlet has been enhanced, making the sediments at the bottom become coarser. The sediments around the Caofeidian foreland went through a process of changing in grain size from fine to coarse and back to fine again, and the sediments are mainly constituted by silt at present.
Geniposide, a main iridoid glucoside component of gardenia fruit, has been shown to possess anti-inflammatory activity. However, its potential use for acute lung injury (ALI) has not yet been ...studied. The aim of this study was to evaluate the anti-inflammatory properties of geniposide using a mouse ALI model. ALI was induced by intranasal injection of lipopolysaccharide (LPS). Pretreatment of mice with geniposide (20, 40, or 80 mg/kg) resulted in a marked reduction in inflammatory cells and total protein concentration in the bronchoalveolar lavage fluid (BALF) of mice. Levels of inflammatory mediators, including tumour necrosis factor- α (TNF- α), interleukin-6 (IL-6), and interleukin-10 (IL-10), were significantly altered after treatment with geniposide. Histological studies using hematoxylin and eosin (H&E) staining demonstrate that geniposide substantially inhibited LPS-induced alveolar wall changes, alveolar haemorrhage, and neutrophil infiltration in lung tissue, with evidence of reduced myeloperoxidase (MPO) activity. In addition, we investigated potential signal transduction mechanisms that could be implicated in geniposide activity. Our results suggest that geniposide may provide protective effects against LPS-induced ALI by mitigating inflammatory responses and that the compound's mechanism of action may involve blocking nuclear factor-kappaB (NF- κB) and mitogen-activated protein kinases (MAPK) signalling pathway activation.
In the Large High Altitude Air Shower Observatory (LHAASO), the main physics objective of the water Cherenkov detector array (WCDA) is to survey the sky for gamma-ray sources in the energy range of ...100 GeV to 30 TeV. In order to extend the dynamic range of the WCDA, a 1.5-inch photomultiplier tube (PMT) is placed aside the 8-inch PMT in each cell of the WCDA. All of these 1.5-inch PMTs (900 in total) consist of the WCDA dynamic extended system (WCDA++). These PMTs are required to maintain linearity within four orders of magnitude. The performance of the 1.5-inch PMTs with a specially designed bi-readout voltage divider is tested with a PMT test system. Accordingly, the effects of the working high voltage and signal width on the dynamic range of the PMTs are studied. The test results show that the dynamic range with a 5% non-linearity for a driven signal width of 5.5 ns is more than 200 kPEs (photoelectrons). The dark noise count rate is less than 200 Hz for a 1 mV threshold at a PMT gain of 2×105. These results confirm that the PMT performance meets the WCDA++ requirements.
•Photomultiplier tube performance of the WCDA++ experiment is presented.•A bi-readout divider circuit maintains linearity within four orders of magnitude.•The pulse signal width affects the linear maximum number of photoelectrons.•The light intensity does not affect the relation between gain and voltage.
Studies demonstrated that chicken ghrelin mRNA was expressed in immune organs of chicken. However, it was not known for its functions in chicken immune system. This study aimed to investigate the ...effects of ghrelin on infectious bursal disease virus (IBDV)-induced acute inflammatory and bursal injury. Chickens were divided into 4 groups. One group was used as control (“C”). The other three groups incubated with IBDV on the 19th d, of which 2 were injected intraperitoneally with 0.5 nmol (“LG”) or 1.0 nmol (“HG”) ghrelin/100g body weight from 18th to 22nd d, respectively, and one was injected intraperitoneally with PBS (“I”). Results showed that cytokines including interleukin (IL)-6, IL-1β, and IL-8 mRNA expression in I group were upregulated significantly after chickens infected with IBDV from 1 d post-infection (dpi) to 3 dpi (P < 0.05). However, the expression level of IL-6, IL-1β, and IL-8 mRNA in LG and HG groups was 7.3, ∼43.3% as much as that of the I group at 2 dpi and 3 dpi (P < 0.05). Moreover, ghrelin administration attenuated significantly the bursal injury from 1 dpi to 7 dpi and prevents the reduction of bird weight gain at 5 dpi and 7 dpi, which were induced by IBDV (P < 0.05). The results indicated that ghrelin could play an important role in the immune system of chicken.
SETDB2 is a H3K9 histone methyltransferase required for accurate chromosome segregation. Its H3K9 histone methyltransferase activity was reported to be associated with chromosomes during metaphase. ...Here, we confirm that SETDB2 is required for mitosis and accurate chromosome segregation. However, these functions are independent of its histone methyltransferase activity. Further analysis showed that SETDB2 can interact with BUBR1, and is required for CDC20 binding to BUBR1 and APC/C complex and CYCLIN B1 degradation. The ability of SETDB2 to regulate the binding of CDC20 to BUBR1 or APC/C complex, and stabilization of CYCLIN B1 are also independent of its histone methyltransferase activity. These results suggest that SETDB2 interacts with BUBR1 to promote binding of CDC20 to BUBR1 and APC3, then degrades CYCLIN B1 to ensure accurate chromosome segregation and mitosis, independently of its histone methyltransferase activity.
The histone methyltransferase SETDB2 interacts with BUBR1 and is required for binding of CDC20 to BUBR1 and APC, thereby mediating degradation of CYCLIN B1 to guarantee accurate chromosome segregation and mitosis exit. This occurs independently of SETDB2's histone methyltransferase activity.
Placenta‐specific protein 1 (Plac1) is a cancer/testis antigen that plays a critical role in promoting cancer initiation and progression. However, the clinical significance and mechanism of Plac1 in ...cancer progression remain elusive. Here, we report that Plac1 is an important oncogenic and prognostic factor, which physically interacts with Furin to drive breast cancer invasion and metastasis. We have shown that Plac1 expression positively correlates with clinical stage, lymph node metastasis, hormone receptor status, and overall patient survival. Overexpression of Plac1 promoted invasion and metastasis of breast cancer cells in vitro and in vivo. Co‐immunoprecipitation and immunofluorescence cell staining assays revealed that interaction of Plac1 and Furin degraded Notch1 and generated Notch1 intracellular domain (NICD) that could inhibit PTEN activity. These findings are consistent with the results of microarray study in MDA‐MB‐231 cells overexpressing Plac1. A rescue study showed that inhibition of Furin and overexpression of PTEN in Plac1 overexpression cells blocked Plac1‐induced tumor cell progression. Taken together, our findings suggest that functional interaction between Plac1 and Furin enhances breast cancer invasion and metastasis and the Furin/NICD/PTEN axis may act as an important therapeutic target for breast cancer treatment.
A mechanism model for placenta‐specific protein 1 (PLAC1) promotes invasion and metastasis of breast cancer. Plac1 physically interacts with Furin, which activates Notch1 intracellular domain/Hes1/PTEN/AKT signaling pathway to promote tumor progression in human breast cancer.
Micro resistance bonding is an essential method to bond micro metal wire and pad for the manufacturing of ever-miniaturized electronic components. However, the bonding quality is unstable due to the ...limited understanding of the interfacial phases. Nano-scale interfacial details of micro resistance bonding Al wire to an Au/Cu pad were investigated by transmission electron microscope (TEM). Metallurgical bonding joints with sufficient interfacial reaction are formed in the Al-Au-Cu system. Under the effect of Joule heat, the center temperature of the bonding structure quickly rose to 868 °C, and the Al element at the interface melted rapidly and reacted with the Au, Cu element forming (Au, Cu)8Al3, (Au, Cu) Al2 and (Cu, Au)3Al8 phases. Moreover, due to the ultrafast cooling speed (1.7 × 104 °C/s), (Cu, Au)3Al8 phase would pre-transform into unstable (Cu, Au)9Al4 (γ phase) phase with body-centred tetragonal (BCT) structure and then form into symmetrical twin structure.
•Al wire was successfully bonded onto Au/Cu pad by ultrafast micro resistance bonding method.•Metallurgical joint was obtained because the sufficient interfacial reaction.•Nano features and composition of the interfacial phases were figured out by TEM.
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