γ-Secretase Functions through Notch Signaling to Maintain Skin Appendages but Is Not Required for Their Patterning or Initial Morphogenesis

AbstractThe role of Notch signaling during skin development was analyzed using Msx2-Cre to create mosaic loss-of-function alleles with precise temporal and spatial resolution. We find that γ-secretase is not involved in skin patterning or cell fate acquisition within the hair follicle. In its absence, however, inner root sheath cells fail to maintain their fates and by the end of the first growth phase, the epidermal differentiation program is activated in outer root sheath cells. This results in complete conversion of hair follicles to epidermal cysts that bears a striking resemblance to Nevus Comedonicus. Sebaceous glands also fail to form in γ-secretase-deficient mice. Importantly, mice with compound loss of Notch genes in their skin phenocopy loss of γ-secretase in all three lineages, demonstrating that Notch proteolysis accounts for the major signaling function of this enzyme in this organ and that both autonomous and nonautonomous Notch-dependent signals are involved

Leveraging the UAV to support Chinese Antarctic expeditions: a new perspective

Recent developments in Unmanned Aerial Vehicles (UAVs) and their applications in various subjects are of interest to polar communities. Due to the harsh climate and dangerous environment, these regions pose challenges for the expedition teams. Several countries have tested the UAV technology to support Antarctic research and logistics. In this trend paper, we provide insightful reviews and discussions on such a prospective topic. Based on a comprehensive literature survey, we firstly summarize the key research progress of UAV in Antarctic studies. Then the examples of risk scenarios during the field exploration are given, after which several promising applications of the UAVs in safety guarantee are illustrated. In particular, we present a case of site-selection for the Chinese first ice sheet airfield, using the data collected in the 34th Chinese National Antarctic Research Expedition (CHINARE). In the end, we highlight the unique value of the UAVs in the popularization of polar science before concluding the advantages and limitations. Considering their excellent performance, we expect more innovations for UAV’s applications in the following Antarctic expeditions

Increasing Ceftriaxone Resistance in Salmonellae, Taiwan

In Taiwan, despite a substantial decline of Salmonella enterica serotype Choleraesuis infections, strains resistant to ciprofloxacin and ceftriaxone persist. A self-transferable blaCMY-2-harboring IncI1 plasmid was identified in S. enterica serotypes Choleraesuis, Typhimurium, Agona, and Enteritidis and contributed to the overall increase of ceftriaxone resistance in salmonellae

Ellagic Acid, the Active Compound of Phyllanthus urinaria, Exerts In Vivo Anti-Angiogenic Effect and Inhibits MMP-2 Activity

This study aimed to assess the potential anti-angiogenic mechanism of Phyllanthus urinaria (P. urinaria) and characterize the major compound in P. urinaria that exerts anti-angiogenic effect. The water extract of P. urinaria and Ellagic Acid were used to evaluate the anti-angiogenic effect in chorioallantoic membrane (CAM) in chicken embryo and human vascular endothelial cells (HUVECs). The matrix metalloproteinase-2 (MMP-2) activity was determined by gelatin zymography. The mRNA expressions of MMP-2, MMP-14 and tissue inhibitor of metalloproteinase-2 (TIMP-2) were analyzed by reverse transcription polymerase chain reaction (RT-PCR). Level of MMP-2 proteins in conditioned medium or cytosol was determined by western blot analysis. We confirmed that P. urinaria's in vivo anti-angiogenic effect was associated with a reduction in MMP-2 activity. Ellagic acid, one of the major polyphenolic components as identified in P. urinaria by high performance liquid chromatography mass spectrometry (HPLC/MS), exhibited the same anti-angiogenic effect in vivo. Both P. urinaria and Ellagic Acid inhibited MMP-2 activity in HUVECs with unchanged mRNA level. The mRNA expression levels of MMP-14 and TIMP-2 were not altered either. Results from comparing the change of MMP-2 protein levels in conditioned medium and cytosol of HUVECs after the P. urinaria or Ellagic Acid treatment revealed an inhibitory effect on the secretion of MMP-2 protein. This study concluded that Ellagic Acid is the active compound in P. urinaria to exhibit anti-angiogenic activity and to inhibit the secretion of MMP-2 protein from HUVECs

High-speed intravascular photoacoustic imaging of lipid-laden atherosclerotic plaque enabled by a 2-kHz barium nitrite raman laser

Lipid deposition inside the arterial wall is a key indicator of plaque vulnerability. An intravascular photoacoustic (IVPA) catheter is considered a promising device for quantifying the amount of lipid inside the arterial wall. Thus far, IVPA systems suffered from slow imaging speed (~50 s per frame) due to the lack of a suitable laser source for high-speed excitation of molecular overtone vibrations. Here, we report an improvement in IVPA imaging speed by two orders of magnitude, to 1.0 s per frame, enabled by a custom-built, 2-kHz master oscillator power amplifier (MOPA)-pumped, barium nitrite [Ba(NO3)2] Raman laser. This advancement narrows the gap in translating the IVPA technology to the clinical setting